高分散白炭黑.doc

高分散白炭黑.doc 高分散低水分白炭黑 ( ) 135of United States Patent 7,799,304 Dromard , et al. September 21, 2010 Highly-structured silica having a low water uptake, preparation method thereof and uses of same Abstract The invention relates to a highly-structured precipitated silica having a low water uptake and high dispersibility in different pasty or solid matrices or media, elastomers or silicon, and to the preparation method thereof. The invention also relates to the use of said silica, for example, as a reinforcing filler in matrices based on elastomers (clear or semi-clear for shoe soles), in silicon matrices (in particular, for the coating of electric cables), as a filler and/or support and/or vehicle in different compositions (food compositions, cosmetic compositions, pharmaceutical compositions, compositions for the production of paints or paper, compositions for the production of porous membrane separators for batteries) or as a thickening agent in toothpastes. Inventors: Dromard; Adrien(Lyons, FR), Chevallier; Yvonick (Saint-Romain-Au-Mont d'Or, FR), Valero; Remi (Saint Jean de Thurigneux, FR), Petit; Dominique (Saint-Cyr-Au-Mont-d'Or, FR) Assignee: RhodiaChimie (Aubervilliers, FR) Appl. No.: 10/583,417 Filed: December 20, 2004 PCT Filed: December 20, 2004 PCT No.: PCT/FR2004/003313 371(c)(1),(April 26, 2007 2),(4) Date: PCT Pub. WO2005/061384 No.: PCT Pub. July 07, 2005 Date: Foreign Application Priority Data Dec 19, 2003 03 15063 [FR] Apr 08, 2004 04 03700 [FR] ; 423/335 Current U.S. Class:423/339 C01B 33/12 (20060101) Current International Class: 423/335,339 Field of Search: References Cited [Referenced By] U.S. Patent Documents 5968470 October 1999 Persello 6001322 December 1999 Chevallier et al. 6335396 January 2002 Chevallier et al. 7033576 April 2006 Chevallier et al. 2005/0074386 April 2005 Valero et al. Foreign Patent Documents 0 407 Jan., EP 262 1991 WO Apr., WO 95/09127 1995 WO Apr., WO 95/09128 1995 WO Dec., WO 0193803 2001 WO Jul., 0305580 WO 2003 1 Other References S Brunauer et al., "Adsorption of Gases in Multimolecular Layers", J. Chem. Soc, vol. 60, Feb. 1938, pp. 309-319. cited by other. Primary Examiner: Vanoy; Timothy C Assistant Examiner: Rump; Richard M Attorney, Agent or Firm: Buchanan Ingersoll & Rooney PC Claims The invention claimed is: 1. A precipitated silica comprising: a CTAB specific surface of 140 to 230 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, a water uptake of less than 6%, a pH of 3.5 to 7.5, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, and a mean particle size or a median particle diameter of less than 30 .mu.m. 2. A precipitated silica according to claim 1, exhibiting: a CTAB specific surface of 145 to 185 m.sup.2/g, a DOP oil uptake of 315 to 450 ml/100 g, a water uptake of less than 6% and greater than 3%, a pH of 4 to 7, and a level of residual anion, expressed as sodium sulfate, of less than or equal 1.5%. 3. A precipitated silica according to claim 2 exhibiting: a CTAB specific surface of 150 to 185 m.sup.2/g, a DOP oil uptake of greater than 320 to 400 ml/100 g, a water uptake of greater than or equal to 4% and of less than or equal to 5.8%, a pH of 4 to 6, and a level of residual anion, expressed as sodium sulfate, of less than or equal to 1%. 4. A precipitated silica according to claim 3, exhibiting: a CTAB specific surface of 150 to 180 m.sup.2/g, a DOP oil uptake of 340 to 380 ml/100 g, and a level of residual anion, expressed as sodium sulfate, of less than or equal to 0.5%. 5. The silica as claimed in claim 1, wherein the mean particle size or a median particle diameter is less than 20 .mu.m. 6. The silica as claimed in claim 1, having a median particle diameter, after deagglomeration under ultrasound, of at most 35 .mu.m. 7. The silica as claimed in claim 1, having a BET specific surface such that the BET-CTAB difference is at most 30 m.sup.2/g. 8. The silica as claimed in claim 1, having a packing density of at most 0.3 g/ml. 9. The silica as claimed in claim 1, in the form of a powder. 10. A process for the preparation of a silica as claimed in claim 1, comprising the following stages: (a) producing a starting vessel heel with a temperature of between 80 and 100.degree. C., comprising water and a silicate, with a concentration of silicate in said vessel heel, expressed as SiO.sub.2 equivalent, being less than or equal to 15 g/l; (b) adding, at a temperature of between 80 and 100.degree. C., an acidifying agent to bring the pH of the medium to a value of between 7 and 8, to form a medium; (c) in the medium thus produced in stage (b), carrying out, at a temperature of between 80 and 100.degree. C., a simultaneous addition of a silicate and of an acidifying agent, with a respective amounts of silicate and of acidifying agent added over time being specifically chosen so that, throughout the duration of the addition: the pH of the reaction medium remains between 7 and 8 and optionally between 7.2 and 7.8; and the concentration of silicon in the medium, expressed as SiO.sub.2 equivalent, remains less than or equal to 35 g/l; (d) adding, at a temperature of between 80 and 100.degree. C., an acidifying agent to the medium obtained on conclusion of stage (c) so as to bring the medium to a pH of between 3 and 6.5 to obtain an aqueous silica dispersion; (e) filtering the aqueous silica dispersion obtained in stage (d) in order to obtain a filtration cake; (f) drying the filtration cake produced on conclusion of the stage (e), optionally washing it beforehand; and (g) optionally milling or micronizing the silica obtained on conclusion of stage (f); wherein as a result of the process the filtration cake exhibits, prior to the drying of it in stage (f), a loss on ignition at 1000.degree. C. of greater than 82%. 11. Shoe soles comprising the silica as defined in claim 1. 12. A matrix based on silicone(s) comprising the silica as defined in claim 1 as reinforcing filler. 13. A carrier for liquids comprising the silica as defined in claim 1. 14. A dentifrice composition in the paste or gel form comprising the silica as defined in claim 1 as a thickening agent. 15. Battery separators comprising the silica as defined in claim 1. 16. The precipitated silica according to claim 1, wherein the water uptake is greater than 3%. 17. The precipitated silica according to claim 5, wherein the mean particle size or median particle diameter is 5 to 15 .mu.m. 18. The precipitated silica according to claim 17, wherein the mean particle size or median particle diameter is 8 to 13 .mu.m. 19. The precipitated silica according to claim 6, wherein the median particle diameter, after deagglomeration under ultrasound, is at most 25 .mu.m. 20. The precipitated silica according to claim 7, wherein the BET-CTAB difference is at most 10 m.sup.2/g . 21. The precipitated silica according to claim 8, wherein the packing density is 0.04 to 0.3 g/ml. 22. The precipitated silica according to claim 10, wherein the temperature in stage (a) is greater than or equal to 90.degree. C. 23. The precipitated silica according to claim 10, wherein the temperature in stage (b) is 90 to 100.degree. C. 24. The precipitated silica according to claim 10, wherein the pH in stage (b) is 7.3 to 7.7. 25. The precipitated silica according to claim 10, wherein the temperature in stage (c) is 90 to 100.degree. C. 26. The precipitated silica according to claim 10, wherein the temperature in stage (d) is 90 to 100.degree. C. 27. The precipitated silica according to claim 10, wherein the loss on ignition and 1000.degree. C. is 84 to 88%. 28. The precipitated silica according to claim 1, wherein the DOP oil uptake is greater than 310 ml/100 g. 29. The precipitated silica according to claim 10, wherein the loss on ignition and 1000.degree. C. is greater than 84%. 30. A precipitated silica comprising: a CTAB specific surface of 140 to 230 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, a water uptake of less than 6%, a pH of 3.5 to 7.5, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, and a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm. Description This application is an application under 35 U.S.C. Section 371 of International Application Number PCT/FR2004/003313 filed on Dec. 20, 2004. The present invention relates to a novel highly-structured precipitated silica having a low water uptake and to a process for the preparation of said silica. It also relates to its use as reinforcing filler in matrices based on elastomers, in particular clear or semi-clear elastomers, for shoe soles or in silicon matrices, for example intended for the coating of electric cables. It also relates to its use in particular as filler and/or carrier and/or excipient in various compositions, such as food, cosmetic or pharmaceutical compositions, compositions for the manufacture of paints or paper, or compositions intended for the manufacture of separating porous membranes for batteries (battery separators), or as thickener agent in dentifrice formulations. "Precipitated" silicas often exhibit a high affinity for water due in particular to the presence at their surface of water-greedy Si--OH groups. The commonest precipitated silicas generally exhibit water uptakes (according to the test defined below) of greater than 7%, generally of the order of 8 to 10%. A process for preparing a precipitated silica having a low water uptake (of the order of 4 to 6%) forms the subject matter of application WO 03/055801; the silica then obtained generally exhibits a CTAB specific surface (external surface) of 100 to 200 m.sup.2/g and a DOP oil uptake of 150 to 300 ml/100 g; it is indicated that this silica can be used for the reinforcing of silicone-based elastomeric matrices, in particular room temperature or high temperature vulcanizable silicone matrices, or of transparent or translucent elastomeric matrices for shoe soles; it is also mentioned that this silica can also be used as thickening agent in organic or aqueous media, in particular toothpastes. Highly structured precipitated silicas exhibiting a DOP oil uptake of greater than 250 ml/100 g, in particular of the order of 300 to 320 ml/100 g, and a CTAB specific surface (external surface) of 70 to 250 m.sup.2/g have already been provided as thickening or texturing agent in dentifrice compositions (application WO 01/93803); such silicas exhibit a water uptake of greater than 7%, that is to say conventional for precipitated silicas. The Applicant has now found a novel precipitated silica which exhibits good dispersing performances in formulation and which advantageously exhibits a high dispersibility in various solid, in particular elastomeric (clear, semi-clear, silicone), or pasty matrices or media, and in even a high light transmission. This is reflected in particular by a good reinforcing and/or thickening power. This silica is particularly suitable for being employed especially as reinforcing filler in matrices based on elastomers, for example clear or semi-clear elastomers, for shoe soles or in silicone matrices, for example room temperature or high temperature vulcanizable silicone matrices. A particularly advantageous application of this silica consists, inter alia, of its use as thickening agent in dentifrices formulations. A first subject matter of the invention consists of a precipitated silica exhibiting: a CTAB specific surface of 140 to 230 m.sup.2/g, preferably of 145 to 195 m.sup.2/g, more preferably of 145 to 185 m.sup.2/g, very particularly of 150 to 185 m.sup.2/g, in particular of 150 to 180 m.sup.2/g, for example of 155 to 175 m.sup.2/g or of 160 to 180 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, preferably of greater than 310 ml/100 g, more preferably of 315 to 450 ml/100 g, very particularly of 320 to 400 ml/100 g, in particular of 340 to 380 ml/100 g, a water uptake of less than 6% and preferably of greater than 3%, very particularly of greater than or equal to 4% and of less than or equal to 5.8%, a pH of 3.5 to 7.5, preferably of 4 to 7, very particularly of 4 to 6, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, preferably of less than or equal to 1.5%, particularly of less than or equal to 1% and very particularly of less than or equal to 0.5%, a mean particle size or a median particle diameter of less than 30 .mu.m or of between 30 .mu.m and 20 mm. According to a first alternative form of the invention, the silica exhibits a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m. According to a second alternative form of the invention, the silica exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm. The silica according to this second alternative form of the invention very preferably exhibits a CTAB specific surface of 145 to 185 m.sup.2/g, in particular of 150 to 180 m.sup.2/g, very particularly of 155 to 175 m.sup.2/g. The CTAB specific surface is the external surface determined according to standard NFT 45-007 (November 1987). The DOP oil uptake is determined according to standard ISO 787/5, dioctyl phthalate being employed. The affinity of a silica with regard to water, expressed by its "water uptake" characteristic, reflects the more or less marked tendency which water molecules exhibit of being adsorbed on the surface of silica. The principle of the test for measuring this characteristic consists in placing the predried sample of silica under given relative humidity conditions for a predefined period of time; the silica hydrates, which causes the weight of the sample to change from a starting value w (in the dried state) to a final value (w+dw). "Water uptake" of a silica will specifically denote the dw/w ratio, expressed as percentage, calculated for a silica sample subjected to the following conditions during the test: preliminary drying: 8 hours at 105.degree. C.; hydration: 24 hours at 20.degree. C. under a relative humidity of 70%. The experimental protocol employed consists in: exactly weighing approximately 2 g of the test silica; drying the silica thus weighed for 8 hours in an oven adjusted to a temperature of 105.degree. C.; determining the weight w of the dried silica obtained on conclusion of the drying operation; placing the dried silica obtained in a closed container (for example in a desiccator) containing a water/glycerol mixture with a water/glycerol ratio by weight of 35/65, so that the relative humidity of the closed medium is 70%, for 24 hours at 20.degree. C.; determining the weight (w+dw) or the silica obtained subsequent to this treatment for 24 hours at 70% relative humidity, this weight being measured immediately after having removed the silica from the desiccator, so as to avoid a variation in the weight of the silica under the influence of the change in hygrometry between the medium at 70% relative humidity and the atmosphere of the laboratory. The pH of the silica is measured according to standard ISO 787/9 (pH of a 5% by weight suspension of silica in deionized water). The silica according to the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of a powder having a mean particle size or a median particle diameter of at most 20 mm. The silica according to the first alternative form of the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of a powder having a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m. This silica is particularly suitable for being employed as reinforcing filler in matrices based on elastomer(s), in particular clear or semi-clear elastomer(s), for shoe soles or as reinforcing filler in matrices based on silicone(s). The silica according to the second alternative form of the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of powder having a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm. It can in particular be a powder exhibiting a median particle diameter of at least 30 .mu.m, preferably of at least 50 .mu.m, and of less than 350 .mu.m, preferably of less than 180 .mu.m; this silica is particularly suitable for being used as thickening or texturing agent in dentifrice compositions or as reinforcing filler in matrices based on silicone(s). The silica can also concern granules (or other aggregates) exhibiting a mean particle size of between 2 and 20 mm. The mean size of the silica particles can be determined according to standard NF X 11507 (December 1970) by dry sieving and determining the diameter corresponding to a cumulative oversize of 50%. The median diameter of the silica particles can be determined by laser diffraction according to standard NF X 11-666. The particle sizer used is of the Malvern Mastersizer type. Measurement Criteria optical concentration: 12.+-.2% measurement liquid: degassed demineralized water absence of ultrasound absence of dispersant duration of the measurement: 10 seconds The precipitated silica according to the invention generally exhibits a median diameter d50 of the particles, after deagglomeration under ultrasound, of at most 35 .mu.m, preferably of at most 30 .mu.m, very particularly of at most 25 .mu.m, in particular of at most 15 .mu.m, for example of at most 10 .mu.m. The median diameter d50 of the silica after deagglomeration under ultrasound is measured using the Malvern Mastersizer particle sizer according to the following test: The power of the ultrasound in the Malvern Mastersizer particle sizer being adjusted to the maximum graduation of 20, an amount of silica is introduced so as to obtain an optical concentration of 12.+-.2%. The median diameter d50 and the percentage of silica particles with a diameter of greater than 51 .mu.m are measured after having kept the vessel subjected to ultrasound for 60 seconds, the vessel being homogenized by circulation of the suspension using a centrifugal pump. The measurement is recorded 10 seconds after ceasing to apply ultrasound. The ability of the silica according to the invention to disperse or to deagglomerate can also be assessed by a particle size measurement (by laser diffraction) carried out on a suspension of silica deagglomerated beforehand by ultrasonication (splitting of the objects from 0.1 to a few tens of microns). The deagglomeration under ultrasound is carried out using a Vibracell Bioblock (600 W) ultrasound generator equipped with a probe with a diameter of 19 mm. The particle size measurement is carried out by laser diffraction on a Sympatec particle sizer. 2 grams of silica are weighed out into a sample tube (height: 6 cm and diameter: 4 cm) and are made up to 50 grams by addition of deionized water: a 4% aqueous silica suspension is thus produced and is homogenized for 2 minutes with magnetic stirring. Deagglomeration is subsequently carried out under ultrasound as follows: the probe being immersed over a length of 4 cm, the output power is adjusted so as to obtain a deviation of the needle of the power dial indicating 20%. Deagglomeration is carried out for 420 seconds. The particle size measurement is subsequently carried out by introducing, into the vessel or the particle sizer, a volume V (expressed in ml) of the homogenized suspension necessary in order to obtain an optical density of the order of 20. A deagglomeration factor F.sub.D is then given by the equation: F.sub.D=10.times.V/optical density of the suspension measured by the particle sizer (this optical density is of the order of 20). This deagglomeration factor F.sub.D is indicative of the level of particles with a size of less than 0.1 .mu.m which are not detected by the particle sizer. This factor increases as the silica exhibits an increased aptitude for deagglomeration. The value of the median diameter d50which is obtained according to this test decreases as the silica exhibits an increased aptitude for deagglomeration. Preferably, the silica according to the invention has a median diameter d50, after deagglomeration under ultrasound, of less than 6 .mu.m, in particular of less than 5 .mu.m, for example of less than 3.5 .mu.m. The silica according to the invention generally exhibits an ultrasound deagglomeration factor F.sub.D of greater than 5.5 ml, in particular greater than 7.5 ml, for example greater than 11.5 ml. The silicas according to the invention preferably exhibit a BET specific surface such that the BET-CTAB difference is at most 30 m.sup.2/g, preferably at most 25 m.sup.2/g, more preferably at most 20 m.sup.2/g, in particular at most 10 m.sup.2/g. The BET specific surface is determined according to the Brunauer-Emmett-Teller method described in the Journal of the American Chemical Society, vol. 60, page 309, February 1938, corresponding to standard NFT 45007 (November 1987). Furthermore, the silicas according to the invention generally exhibit a packing density, measured according to standard ISO 787/11, of at most 0.3 g/ml, preferably of 0.04 to 0.3 g/ml, more preferably of 0.05 to 0.3 g/ml, in particular of 0.05 to 0.2 g/ml; this packing density can also be between 0.1 and 0.3 g/ml, in particular between 0.1 and 0.27 g/ml, especially between 0.15 and 20.25 g/ml. The loss on ignition (LOI) of the silica of the invention, measured according to standard ISO 3262/11, after treatment at 1000.degree. C., is generally such that the difference between the LOI and the water content is less than 3.2%, preferably less than 3%, very particularly less than 2.7%. The water content is the residual water content measured according to standard ISO 787/2, after heat treatment at 105.degree. C. for 2 hours. The water content of the silica according to the invention, in particular when it is intended to be used as filler in silica matrices, is generally less than 5%, preferably less than 4%, for example at most 3%, of the total weight of the sample. The silica according to the invention can additionally exhibit a level of transmission of at least 70% at a refractive index in glycerol lying between 1.450 and 1.467. The refractive index under consideration is that corresponding to the most transparent suspension (maximum transmission) of this silica in various water-glycerol solutions, which transparency is determined by the transmission at 589 nm with a spectrophotometer. Each suspension is obtained by dispersing 2 g of silica in 18 g of water/glycerol solution and then deaerating under a slight vacuum before reading the transmission (reading carried with the silica-free water/glycerol solution as reference product) on the spectrophotometer and the refractive index on a refractometer. A second subject matter of the invention consists of a process for the preparation of the highly-structured silica having a low water uptake described above, comprising the following successive stages: (a) producing a starting vessel heel with a temperature of between 80 and 100.degree. C., preferably of greater than or equal to 90.degree. C., comprising water and a silicate, the concentration of silicate in said vessel heel, expressed as SiO.sub.2 equivalent, being less than or equal to 15 g/l; (b) adding, at a temperature of between 80 and 100.degree. C., preferably 90 and 100.degree. C., an acidifying agent to bring the pH of the medium to a value of between 7 and 8, preferably to a value of between 7.2 and 7.8 and advantageously between 7.3 and 7.7 (typically to a value substantially equal to 7.5); (c) in the medium thus produced, carrying out, at a temperature of between 80 and 100.degree. C., preferably between 90 and 100.degree. C., the simultaneous addition of a silicate and of an acidifying agent, the respective amounts of silicate and of acidifying agent added over time being specifically chosen so that, throughout the duration of the addition: the pH of the reaction medium remains between 7 and 8 and advantageously between 7.2 and 7.8; and the concentration of silicon in the medium, expressed as SiO.sub.2 equivalent, remains less than or equal to 35 g/l; (d) adding, at a temperature of between 80 and 100.degree. C., preferably between 90 and 100.degree. C., an acidifying agent to the medium obtained on conclusion of stage (c) so as to bring the medium to a pH of between 3 and 6.5; (e) filtering the aqueous silica dispersion obtained; (f) drying the filtration cake produced on conclusion of the filtration, preferably washing it beforehand; (g) optionally milling or micronizing the silica obtained on conclusion of stage (f), said process being characterized in that the filtration cake exhibits, prior to the drying of it in stage (f), a loss on ignition at 1000.degree. C. of greater than 82%, preferably of at least 84%, very particularly of 84 to 88%. The silicates employed in stages (a) and (c) of the process can be chosen from all the common forms of silicates. Advantageously, the silicates used according to the invention are alkali metal silicates, such as, for example, sodium or potassium silicates. Particularly preferably, the silicate of stage (a) is a sodium silicate, as well as that added during stage (c). The sodium silicate employed is then generally characterized by an SiO.sub.2/Na.sub.2O ratio by weight of between 2 and 4, advantageously between 3 and 3.6, this SiO.sub.2/Na.sub.2O ratio by weight preferably being between 3.3 and 3.5 (typically, this ratio is substantially equal to 3.4). The vessel heel of stage (a) of the process is generally provided in the form of an aqueous silicate solution, the concentration of which is characteristically less than or equal to 15 g/l. Typically, the concentration of silicate in the vessel heel of stage (a), expressed as SiO.sub.2 equivalent, is between 1 and 15 g/l. This concentration of silicate in the vessel heel of stage (a), expressed as SiO.sub.2 equivalent, is advantageously less than or equal to 10 g/l and preferably less than or equal to 9 g/l. The vessel heel of stage (a) generally has a pH of the order of 9 to 13. Stage (b) of the process of the invention consists specifically in reducing this value of the pH by addition of an acidifying agent, so as to bring the pH to the medium within the range from 7 to 8, where it has been demonstrated that the reaction for the precipitation of the silica takes place in optimum fashion. The term "acidifying agent" is understood to mean any inorganic or organic acidic compound capable of being able to lead to a reduction in the pH of the vessel heel. Thus, use may advantageously be made, as acidifying agent, of an inorganic acid, such as sulfuric acid, hydrochloric acid or nitric acid, or alternatively of an organic acid, such as acetic acid, formic acid or carbonic acid. Advantageously, no electrolyte is added during the process, in particular in stage (a). The term of "electrolyte" is to be understood here as normally accepted, that is to say that it denotes any ionic or molecular substance which, when it is in solution, decomposes or dissociates to form ions or charged particles (the usual electrolytes are alkali metal and alkaline earth metal salts, in particular the salt of the starting silicate metal and of the acidifying agent, such as sodium chloride in the case of the reaction of a sodium silicate with hydrochloric acid or sodium sulfate in the case of the reaction of a sodium silicate with sulfuric acid). The acidifying agent employed in stage (b) of the process is preferably sulfuric acid, in particular when the silicate present in the starting vessel heel is an alkali metal silicate. Generally, the acidifying agent of stage (b) is most often introduced in the form of an aqueous solution, preferably a dilute aqueous solution, generally with a normality of between 0.25 and 8N. Thus, in stage (b), the reduction in the pH of the medium can advantageously be carried out by addition of an aqueous sulfuric acid solution with a concentration of between 10 and 350 g/l and preferably between 50 and 250 g/l. Whatever the exact nature of the acidifying agent of stage (b), this acidifying agent must be employed so that its addition results in the reduction in the pH of the medium down to a value of between 7 and 8. The amount of acidifying agent to be employed in this context is generally determined in practice by measuring the change in the pH during the addition, the addition of the acidifying agent of stage (b) being continued until the pH reaches the desired value. Furthermore, the addition of stage (b) is preferably carried out gradually, that is to say advantageously, as a general rule, with an addition time of between 3 and 60 minutes, generally at least equal to 5 minutes and preferably at least equal to 10 minutes. However, this addition time is advantageously less than 30 minutes. According to a specific embodiment which can be envisaged for stage (b), this stage can include a maturing process which, if appropriate, is carried out by leaving the medium to change for a period of time generally of between 5 and 30 minutes, preferably at a temperature of between 90 and 100.degree. C., it being understood that, subsequent to this maturing, the pH of the reaction medium is adjusted if necessary, in particular by addition of an acidifying agent, so that, on conclusion of stage (b), the pH of the medium lies within the pH range between 7 and 8 and advantageously within the abovementioned preferred ranges. Subsequent to stage (b), by which the pH of the reaction medium is brought within the preferred region from 7 to 8 and preferably to approximately 7.5, stage (c) of the process consists in continuing the process for the precipitation of silica by introducing additional silicate and by specifically maintaining the pH of the medium within the region between 7 and 8, preferably at a substantially constant value, this constant value then preferably being close to 7.5, that is to say generally between 7.3 and 7.7. To do this, the silicate of stage (c) is introduced in conjunction with an acidifying agent which opposes the increase in pH which would be observed by adding the silicate alone. Preferably, stage (c) of the process of the invention is carried out immediately after obtaining, for the medium, the desired pH in stage (b). The "simultaneous addition" of the silicate and of the acidifying agent which is carried out during stage (c) advantageously consists of a continuous addition of silicate to the medium, during which the pH of the medium is measured and during which the value of this pH is regulated by introduction of the acidifying agent, it being possible, for example, for this introduction of the acidifying agent to be carried out as soon as the pH of the medium becomes greater than a control value of between 7 and 8, this control value generally being set in a vicinity of 7.5. By this means, success is achieved in maintaining, in the medium, a substantial constant value of the pH, that is to say advantageously varying to +/-0.2 pH unit (preferably to +/-0.1 pH unit) around a set value, generally of between 7.3 and 7.7. Alternatively, the simultaneous addition of stage (c) can also consist of a continuous addition of acidifying agent to the medium, the pH then being regulated during the addition by introduction of the silicate, it being possible here again for this introduction with the silicates to be, for example, carried out as soon as the pH of the medium becomes less than a control value of between 7 and 8 generally fixed in the vicinity of 7.5. By this means, success is also achieved in keeping the medium at a substantially constant pH, that is to say advantageously varying to +/-0.2 pH unit (preferably to +/-0.1 pH unit) around a set value generally between 7.3 and 7.7. According to yet another embodiment which can be envisaged, the simultaneous addition of stage (c) can also consist of a continuous addition both of acidifying agent and of silicate with concentrations and flow rates calculated so that, throughout the duration of the addition, the pH of the medium remains between 7 and 8 and preferably between 7.2 and 7.8. In this case, the pH of the medium generally has a tendency to change during stage (c) or remaining within the abovementioned range but it can, in some cases, remain substantially equal to a constant value advantageously of the order of 7.5. In this context, it is generally preferable for, throughout stage (c), the instantaneous flow rates corresponding to the amount of silicate functional groups (expressed as molar equivalent of NaOH) introduced per second (recorded as d.sub.s) and the amount of acid functional groups (as moles) introduced per second (recorded as d.sub.A) to be such that the ratio d.sub.S/d.sub.A remains continuously between 1.01 and 1.09 and preferably between 1.02 and 1.07. Whatever the exact embodiment of stage (c), the silicate and the acidifying agent used are generally identical to those employed in stages (a) and (b). Thus, the silicate of stage (c) is preferably an alkali metal silicate, advantageously a sodium silicate, and the acidifying agent is preferably a strong inorganic acid, generally sulfuric acid. Insofar as, during the simultaneous addition of stage (c), the concentration of silicon in the medium (expressed as SiO.sub.2 equivalent) characteristically has to be kept below or equal to 35 g/l, the silicate introduced into the reaction medium during stage (c) is generally in the form of a dilute aqueous solution, that is to say with a concentration, expressed as SiO.sub.2 equivalent, advantageously of between 10 and 360 g/l, preferably of less than 300 g/l and advantageously of less than 270 g/l, this being very particularly the case when alkali metal silicates, such as sodium silicates, are used. In the same way, the acidifying agent is generally in the form of a dilute aqueous solution which generally has a normality of between 0.25 and 8N and preferably between 0.5 and 4N. Thus, in the specific case of the use of an aqueous sulfuric acid solution as acidifying agent of stage (c), for example, the concentration of the solution is advantageously between 25 and 380 g/l and preferably between 50 and 300 g/l. It should be emphasized that, in view of the use of dilute concentrations in the medium for the precipitation of the silicas, the concentrations of salts in this medium, in particular related to the reaction of the silicate and of the acidifying agent, are characteristically extremely low, which is reflected by a weak ionic strength within the precipitation medium employed. Without wishing to be committed in any way to a specific theory, it appears possible to hypothesize that the control of the pH and of the concentrations employed makes it possible to minimize the formation of surface SiOH groups. So as to further improve the control of the formation of the silica, it is particularly advantageous to carry out the simultaneous addition of stage (c) with silicate and acidifying agent flow rates which are relatively low, that is to say generally with an addition time of stage (c) preferably of between 15 and 300 minutes and preferably between 30 and 100 minutes. This is because such addition times generally result in the production of silicon particles exhibiting extremely low levels of surface Si--OH groups. Generally, stage (c) of the process of the invention is carried out with stirring at a temperature of between 80 and 100.degree. C. and generally at the same temperature as the addition of stage (b). Thus, the operating temperature of stage (c) can advantageously be between 90 and 100.degree. C. and it is preferably of the order of 95.degree. C. According to a specific alternative form of the process, this applying in particular with regard to the preparation of silicas which can be used in applications other than food, dentifrice, cosmetic or pharmaceutical applications, it is possible to introduce, into the reaction medium, during stage (c), preferably at the end of the stage (that is to say, typically during the period corresponding to the final quarter of this stage, generally during the final 5 to 15 minutes of this stage), an aluminum-based compound, preferably a salt of acidic nature, such as an aluminum sulfate, or alternatively a compound of basic nature, such as a sodium aluminate. The amount of aluminum compound introduced in this context is generally such that, within the reaction medium, the Al/SiO.sub.2 ratio is between 0.1 and 1% by weight, this ratio preferably being at most equal to 0.6% and preferably less than or equal to 0.5%. Whatever the exact embodiment of stage (c), the reaction medium is, on conclusion of this stage, specifically at a pH of between 7 and 8 and preferably of the order of 7.5. Depending on the applications envisaged for the silica, stage (d) of acidification of the medium in the pH region from 3 to 6.5 can be varied by the amount of acidifying agent added. Preferably, the pH of the medium reached on conclusion of stage (d) is between 3.2 and 5.5. The acidifying agent of stage (d) can without distinction be identical to or different from that or those employed in stages (b) and (c). Preferably, this acidifying agent of stage (d) is introduced into the medium in the form of an aqueous solution with a normality of between 0.25 and 8N. Advantageously, it is an aqueous sulfuric acid solution generally at a concentration of between 25 and 380 g/l, if appropriate. The combined stages (a), (b), (c) and (d) of the process are preferably carried out at a temperature of between 90 and 100.degree. C., advantageously at a temperature of between 93 and 97.degree. C. and more advantageously still at a temperature substantially equal to 95.degree. C. throughout the process. According to an advantageous alternative form of the process of the invention, the aqueous silica dispersions obtained on conclusion of stages (c) and (d) can be subjected to a maturing stage generally carried out, if appropriate, by leaving the medium, preferably with stirring, at a temperature of between 90 and 100.degree. C. for a period of time which can advantageously be between 15 and 240 minutes and preferably for a period of time of greater than 30 minutes, the temperature during the maturing preferably being substantially constant (if appropriate, advantageously substantially equal to 95.degree. C.) or else increasing (generally stepwise, if appropriate) within the temperature range extending from 90 to 100.degree. C. It should be emphasized that the addition of an aluminum compound, in particular of aluminum sulfate type, which can be envisaged at the end of stage (c) can also be carried out during stage (d) or alternatively during the subsequent maturing stage, when this stage is carried out. Thus, generally, this addition of an aluminum-based compound to the medium can take place between stage (c) and stage (e). Stages (e) and (f) of the process consist overall in recovering a silica in the solid form from the dispersion obtained on conclusion of the preceding stages. Generally, during this stage (e), the dispersion obtained on conclusion of stage (d) and of the optional subsequent maturing stage is filtered through a filter press or is filtered under vacuum using a rotary filter, a belt filter or a flat filter, this filtration resulting in a "silica cake" being obtained. The silica cake obtained is then generally subjected to a washing stage, generally washing with water, preferably with a sufficiently long duration, so as to reduce its content of salts, and it is subsequently subjected in stage (f) to drying, in particular by a suitable atomization, for example using a rotary, nozzle, liquid pressure or two-fluid atomizer. In this context, the silica cake is generally disintegrated beforehand, so as to form a silica slurry with a viscosity sufficiently low to provide for the pumping thereof to the atomizer. According to the invention, this slurry exhibits a loss on ignition at 1000.degree. C. of greater than 82% by weight, preferably of at least 84% by weight, more particularly of 84 to 88% by weight. If appropriate, the disintegrating operation can, for example, be carried out in a known way by subjecting the cake to a mechanical action and optionally to a chemical action (addition of an acid or of an aluminum-based compound). Generally, the slurry of low viscosity resulting from such a disintegration operation is provided in the form of an aqueous silica dispersion which can be directly pumped to an atomizer for stage (f). The dried silicas obtained in conclusion of stage (f) can optionally be subjected to a stage of agglomeration, in particular by direct compression, by wet granulation (that is to say, with use of a binder, such as water), by extrusion and, preferably, by dry compacting. When the latter technique is employed, it can prove to be advantageous, before carrying out the compacting, to deaerate (operation also referred to as predensifying or degassing) the pulverulent products so as to remove the air included in the latter and to provide more uniform compacting. On conclusion of the agglomeration stage, the products can be graded to a desired size, for example by sieving. The compacted precipitated silica capable of being obtained is then advantageously provided in the form of granules. If appropriate, these granules can be provided in the most diverse shapes. The shapes which may be especially mentioned by way of example are spherical, cylindrical, parallelepipedal, tablet, flake, pellet and extrudate of circular or polylobar section. The mean dimensions of these granules are preferably between 2 and 20 mm. The silica obtained on conclusion of stage (f) and then optionally agglomerated preferably exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm. The silica obtained on conclusion of stage (f) and then optionally agglomerated can subsequently be micronized or, preferably, milled. The silica then obtained preferably exhibits a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m. Micronizing can be carried out with a micronizer, such as an air jet mill. Milling can be carried out in particular using a mechanical mill, for example of the ACM, Forplex, type, in particular a classifier hammer mill. The precipitated silicas according to the present invention exhibit a very good aptitude for dispersing. They are particularly suitable, advantageously when they exhibit a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, for example between 8 and 13 .mu.m (silicas according to the first alternative form of the invention), for use as reinforcing filler in matrices based on elastomer(s), in particular clear or semi-clear elastomer(s), for shoe soles, as reinforcing filler in matrices based on silicone(s), in particular high temperature or room temperature vulcanizable silicone elastomer matrices, on which they confer good rheology properties, while providing them with highly satisfactory mechanical properties. The silicas according to the invention have a particular advantageous application in the reinforcing of matrices based on elastomers, in particular clear or semi-clear elastomers, intended for the manufacture of shoe soles; these dispersible silicas make it possible for strong reinforcing of the transparent or translucent matrices used for the preparation of components made of transparent or translucent rubber which are constituents of shoe soles. Advantageously, they make it possible to obtain reinforced matrices having very good transparency. The amount of silica according to the invention which can be used in this type of matrix is generally between 10 and 50%, in particular between 20 and 40%, with respect to the weight of the elastomer(s). The silicas according to the invention have an equally advantageous application in the reinforcing of high temperature vulcanizable pasty or elastomeric organosilicon compositions (matrices) (HTV silicones, for example) or room temperature vulcanizable pasty or elastomeric organosilicon compositions (matrices) intended in particular for an insulation role, in particular the coating of electric cables. Said silicone-based matrices, in particular those intended for an insulation role, can be formed by extrusion, before being crosslinked. The low value for water uptake of the silicas of the invention makes it possible to avoid or to limit the formation of bubbles, in particular during the extrusion. These silica-based matrices can also be formed by molding. The silicas according to the invention advantageously confer, on the silicone matrices, very good electrical and mechanical properties, in particular with regard to tear strength or ultimate strength. The nature of the vulcanizable organopolysiloxane or organopolysiloxanes present in this type of composition and that of the vulcanizing agents and other additives optionally present, as well as the vulcanizing conditions, are well known to a person skilled in the art; they are disclosed in particular in application WO 03/055801. The amount of silica according to the invention which can be employed for the reinforcing of said matrices based on silicones can range from 3 to 20% when silicone pastes are concerned or from 5 to 50%, preferably from 10 to 40%, when a composition of elastomeric nature is concerned. A possible application of the silicas according to the invention lies in their use as carrier for liquids, in particular due to their good absorption capacity and a highly satisfactory flowability. Mention may be made, as liquids, of organic liquids, such as organic acids, surface-active agents, for example of anionic or nonionic type, organic additives for rubber/polymers, or pesticides. Preferably, use is made here, as liquids, in particular of liquid additives, such as flavorings, colorants, liquid food supplements (in particular for the feeding of animals (for example vitamin E, vitamin E acetate or choline hydrochloride)) or preservatives, preferably carboxylic acids (propionic acid, for example). The conditioned compositions comprising at least one liquid absorbed on a carrier formed by a silica according to the invention preferably exhibit a liquid content of at least 50% by weight, in particular of between 50 and 75% by weight, for example between 50 and 65% by weight. Furthermore, the silicas of the invention can be employed as filler and/or carrier and/or excipient in various compositions, such as food, cosmetic or pharmaceutical compositions or compositions for the manufacture of paints or paper. Mention may also be made of the use, for example in an amount of the order of 60% by weight, of the silica of the invention as carrier for solvent and/or for oil in compositions based on polymers intended for the preparation of separating porous membranes for batteries (battery separator); the solvent and/or the oil carried, once extracted after extrusion/calendaring, give rise to a network of pores. The silica according to the invention, advantageously when it exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm (silica according to the second alternative form of the invention), can be incorporated in dentifrice compositions during the preparation of said compositions, which can be provided in the paste or gel form, and can thus make it possible to thicken these compositions or to provide them with the texture. According to the invention, said silica can be used as thickening or texturing agent in a proportion of 0.1 to 20%, preferably of 0.5 to 15%, very particularly of 1 to 10%, by weight of the dentifrice composition. Said dentifrice composition can additionally comprise other normal ingredients, in particular water-insoluble inorganic abrasive agents, optionally other thickening agents, humectants, and the like. Mention may in particular be made, as abrasive agents, of abrasive silicas, calcium carbonate, hydrated alumina, bentonite, aluminum silicate, zirconium silicate or sodium, potassium, calcium and magnesium metaphosphates and phosphates. The total amount of abrasive powder(s) can constitute of the order of 5 to 50% of the weight of the dental composition. Mention may be made, among the other thickening agents, of xanthan gum, guar gum, carrageenans, cellulose derivatives, alginates, in an amount which can range up to 5% of the weight of said composition, and the like. Mention may be made, among the humectant agents, for example, of glycerol, sorbitol, polyethylene glycols, polypropylene glycols or xylitol, in an amount of the order of 2 to 85%, preferably of the order of 3 to 55%, of the weight of dentifrice composition, expressed on a dry basis. In addition, these compositions can comprise in particular surface-active agents, detergent agents, colorants, antibacterials, fluorinated derivatives, opacifiers, flavorings, sweeteners, agents for combating tartar or plaque, bleaching agents, sodium bicarbonate, antiseptics, enzymes or natural extracts (camomile, thyme, and the like). The following examples illustrate the invention without, however, limiting the scope thereof. EXAMPLES 1-3 Model Opaque Toothpaste TABLE-US-00001 sorbitol (Neosorb 70/70 (Roquette Freres)) 45 polyethylene glycol PEG 1500 5 sodium saccharinate 0.2 sodium fluoride 0.08 sodium monofluorophosphate 0.72 water 24.2 abrasive silica (Tixosil 63, sold by Rhodia) 10 silica of the invention 7 titanium dioxide 1 spearmint flavoring 1 foaming agent (30% in water): 5 Texapon Z 95 P (Cognis) Measurement of the Viscosity of a Dentifrice Formulation The viscosity is determined on a tube of paste with a diameter of 25 mm at predetermined periods at 37.degree. C. after preparation of the paste. The measurement equipment used is a Brookfield RVT viscometer equipped with a Helipath device. The TE spindle is used at 5 rpm (revolutions per minute). The measurement is carried out in a downward direction after 90 seconds. Example 1 14 000 g of water and 450 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46. After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 95.degree. C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute). Once the pH of 7.5 was reached, 3045 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 35 grams per minute (duration of addition: 87 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium. Taking stock, 3383 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 40 grams of sulfuric acid solution added per minute. After the period of addition of 87 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.6. Maturing was carried out by leaving the solution to stir for 5 minutes. The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 80.5%, was disintegrated mechanically at a pH of 5.5 and was then dried by rotary atomization. The physicochemical characteristics of the unmilled dry silica obtained are as follows: pH: 5.9 median particle diameter: 80 .mu.m median diameter after ultrasound: 31.0 .mu.m % greater than 51 .mu.m after ultrasound: 18.6 Na.sub.2SO.sub.4 content: 1.6% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 133 m.sup.2/g BET specific surface: 143 m.sup.2/g DOP oil uptake: 305 ml/100 g loss on ignition at 1000.degree. C.: 6.5% residual water content after 2 hours at 105.degree. C.: 3.9% water uptake: 5.8% transmission: 80% at a refractive index of 1.460 packing density (PD): 0.27 g/ml viscosity of the model toothpaste after 4 weeks: 250 mPas Example 2 The operations described in comparative example 1 are repeated, the dried product being milled so as to obtain a median particle diameter of 10 .mu.m. The physicochemical characteristics of the milled dry silica obtained are as follows: pH: 5.9 median particle diameter: 10 .mu.m median diameter after ultrasound: 7 .mu.m % greater than 51 .mu.m after ultrasound: 1.0 Na.sub.2SO.sub.4 content: 1.6% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 133 m.sup.2/g BET specific surface: 143 m.sup.2/g DOP oil uptake: 315 ml/100 g loss on ignition at 1000.degree. C.: 7% residual water content after 2 hours at 105.degree. C.: 4.4% water uptake: 5.9% transmission: 80% at a refractive index of 1.460 packing density (PD): 0.1 g/ml viscosity of the model toothpaste after 4 weeks: 325 mPas Example 3 14 000 g of water and 630 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46. After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 95.degree. C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute). Once the pH of 7.5 was reached, 3600 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 48 grams per minute (duration of addition: 75 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium. Taking stock, 3975 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 53 grams of sulfuric acid solution added per minute. After the period of addition of 90 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.4. Maturing was carried out by leaving the solution to stir for 5 minutes. The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 86%, was disintegrated mechanically at a pH of 5 and was then dried by rotary atomization. The physicochemical characteristics of the unmilled dry silica obtained are as follows: pH: 5.3 median particle diameter: 65 .mu.m median diameter after ultrasound: 22 .mu.m % greater than 51 .mu.m after ultrasound: 3.3 Na.sub.2SO.sub.4 content: 1.0% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 182 m.sup.2/g BET specific surface: 185 m.sup.2/g DOP oil uptake: 340 ml/100 g loss on ignition at 1000.degree. C.: 6.5% residual water content after 2 hours at 105.degree. C.: 3.9% water uptake: 5.7% transmission: 85% at a refractive index of 1.460 packing density (PD): 0.18 g/ml viscosity of the model toothpaste after 4 weeks: 615 mPas Example 4 14 000 g of water and 450 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46. After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 98.degree. C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute). Once the pH of 7.5 was reached, 3150 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 35 grams per minute (duration of addition: 90 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium. Taking stock, 3510 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 39 grams of sulfuric acid solution added per minute. After the period of addition of 90 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.4. Maturing was carried out by leaving the solution to stir for 5 minutes. The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 86.4%, was disintegrated mechanically at a pH of 4.3 and was then dried by rotary atomization. The dried silica was subsequently milled using a classifier hammer mill. The physicochemical characteristics of the silica in the powder form obtained are as follows: pH: 4.6 mean particle size: 12 .mu.m Na.sub.2SO.sub.4 content: 0.25% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 166 m.sup.2/g BET specific surface: 170 m.sup.2/g DOP oil uptake: 365 ml/100 g loss on ignition at 1000.degree. C.: 5% residual water content after 2 hours at 105.degree. C.: 2.5% ater uptake: 5.8% packing density (PD): 0.08 g/ml * * * * * ( 1(135 )35) of的 United States Patent美国专利 7,799,3047,799,304 Dromard , et al.Dromard,罗卓荆。 September 21, 20102010年9月21日, Highly-structured silica having a low water uptake, preparation method thereof and uses of sameHighly-structured水分吸收硅较为低下、制备 ,并同时使用相同 Abstract文摘 The invention relates to a highly-structured precipitated silica having a low water uptake and high dispersibility in different pasty or solid matrices or media, elastomers or silicon, and to the preparation method thereof.本发明涉及一种较为低下了沉淀法白炭黑highly-structured水分吸 收和高分散性馅饼或固体矩阵在不同或媒体、弹性体或硅和制备方法》,制定本办法。The invention also relates to the use of said silica, for example, as a reinforcing filler in matrices based on elastomers (clear or semi-clear for shoe soles), in silicon matrices (in particular, for the coating of electric cables), as a filler and/or support and/or vehicle in different compositions (food compositions, cosmetic compositions, pharmaceutical compositions, compositions for the production of paints or paper, compositions for the production of porous membrane separators for batteries) or as a thickening agent in toothpastes.本发明也涉及到使用说硅石,例如,作为加强填料矩阵基于合成橡胶(透明或semi-clear底为鞋),在硅矩阵(特别是,在涂料电气电缆),作为填料和/或支持和/或汽车在不同成分(食物成分、化妆品成分、药品成分、成分用于生产涂料或纸生产、成分的多孔膜分离器电池)或增稠剂在牙膏。 Inventors:Dromard; Adrien (Lyons, FR), Chevallier; Yvonick (Saint-Romain-Au-Mont d'Or, 发明家FR), Valero; Remi (Saint Jean de Thurigneux, FR), Petit; Dominique : (Saint-Cyr-Au-Mont-d'Or, FR)Dromard;?里昂 (FR);Yvonick(Saint-Romain-Au-Mont,Chevallier d多尔、阻燃),Valero;Remi(圣 琼?德?Thurigneux、阻燃),可爱的;多米尼克(Saint-Cyr-Au-Mont-d多尔FR), Assignee:Rhodia ChimieRhodia Chimie(Aubervilliers, FR)(Aubervilliers FR), 受让人: 李波。Appl.10/583,41710/583,417 号码No.:: 申请December 20, 20042004年12月20日, Filed:: PCT Filed:PCTDecember 20, 20042004年12月20日, 申请: PCT 号PCT/FR2004/003313FR2004/003313 PCT / No.:PCT 码: 371(c)(1),( 2),(4) Date:371(c)April 26, 20072007年4月26日 一、二、()() 日期(4): PCT 酒Pub.PCTWO2005/061384WO2005/061384 吧。号No.: 码: PCT 酒Pub.PCTJuly 07, 20052005年7月7日, 吧。Date: 日期: Foreign Application Priority Data国外申请优先数据 Dec 19, 2003 [FR]12月 03 1506303 15063 19日,2003(FR] Apr 08, 2004 [FR]4月8 04 0370004 03700 号,2004(FR] 目前美国。423/339 ; 423/335423/335 423/339 Current U.S. Class: 的班 : C01B 33/12 (20060101)C01B 33/12(20060101) Current International Class: 当前国际班 : 领域的搜索423/335,339423/335,339 Field of Search:: References Cited引用[Referenced By]引用][ U.S. Patent Documents美国专利资料, 59684705968470 October 19991999年10月 PerselloPersello 60013226001322 December 19991999年12月 Chevallier et al.Chevallier孙俐。 63353966335396 January 20022002年1月 Chevallier et al.Chevallier孙俐。 70335767033576 April 20062006年4月 Chevallier et al.Chevallier孙俐。 2005/00743862005/0074386 April 20052005年4月 Valero et al.Valero孙俐。 Foreign Patent Documents国外专利文档 Jan., 0 407 2620 407 19911991年 EPEP 262 1月, Apr., WO 95/09127我 19951995年 WO我们 们95/09127 4月, Apr., WO 95/09128我 19951995年 WO我们 们95/09128 4月, Dec., WO 0193803我 20012001年 WO我们 们0193803 12月, Jul., WO 03055801 20032003年 WO我们 我们03055801 《 Other References其他参考资料 S Brunauer et al., "Adsorption of Gases in Multimolecular Layers", J. Chem.S Brunauer苏达权 等,“吸附层Multimolecular气体化学”,国立。Soc, vol. 60, Feb. 1938, pp. 309-319. cited by other. 那2卷,第3期,第60岁。309-319. 1938年被其他。 Primary Examiner:主要考官:Vanoy; Timothy CVanoy提摩太C。 Assistant Examiner:助理考官:Rump; Richard M理查德?米臀部。 Attorney, Agent or Firm:律师、代理或公司治理结构:Buchanan Ingersoll & Rooney PC布坎南 英格索尔和鲁尼的电脑 Claims声称 The invention claimed is:这项发明声称是: 1.1。A precipitated silica comprising: a CTAB specific surface of 140 to 230 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, a water uptake of less than 6%, a pH of 3.5 to 7.5, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, and a mean particle size or a median particle diameter of less than 30 .mu.m.一个沉淀法二氧化硅包括:一个溴化十六烷 三甲基铵的比表面积等140到230 m.sup.2 / g,吸收大于DOP油300毫升/ 100克,水资源量的少 于6%,酸碱度的3.5至7.5,剩余的水平负离子,表示为盐,小于或等于2%,和一个平均粒径偏小或 平均粒径小于30 .mu.m。 2.2。A precipitated silica according to claim 1, exhibiting: a CTAB specific surface of 145 to 185 m.sup.2/g, a DOP oil uptake of 315 to 450 ml/100 g, a water uptake of less than 6% and greater than 3%, a pH of 4 to 7, and a level of residual anion, expressed as sodium sulfate, of less than or equal 1.5%.一个沉淀法二氧化硅根据第一条要求,展示:溴化十六烷三甲基铵的比表面积等 145改为185 m.sup.2 / g,油量的315 DOP 450毫升/ 100克,水资源量的少于6%,并且大于3%,酸 碱度的4到7,剩余的维持负离子,表示为盐,小于或等于1.5%。 3.3。A precipitated silica according to claim 2 exhibiting: a CTAB specific surface of 150 to 185 m.sup.2/g, a DOP oil uptake of greater than 320 to 400 ml/100 g, a water uptake of greater than or equal to 4% and of less than or equal to 5.8%, a pH of 4 to 6, and a level of residual anion, expressed as sodium sulfate, of less than or equal to 1%.一个沉淀法二氧化硅根据权利要求2展 示:溴化十六烷三甲基铵的比表面积等150改为185 m.sup.2 / g,吸收大于DOP油320 400毫升/ 100克,水资源量的大于等于4%和小于或等于5.8%酸碱度,4 - 6,一定程度的残余负离子,表示 为盐,小于或等于1%。 4.4。A precipitated silica according to claim 3, exhibiting: a CTAB specific surface of 150 to 180 m.sup.2/g, a DOP oil uptake of 340 to 380 ml/100 g, and a level of residual anion, expressed as sodium sulfate, of less than or equal to 0.5%.一个沉淀法二氧化硅根据权利要求3,展示:溴化十 六烷三甲基铵的比表面积等150到180 m.sup.2 / g,吸油DOP 340 - 380毫升/ 100克,一定程度的 残余负离子,表示为盐,小于或等于0.5%。 5.5。The silica as claimed in claim 1, wherein the mean particle size or a median particle diameter is less than 20 .mu.m.白碳黑做的如权利要求1所,其中所述平均粒径偏小或中值粒径小于 20 .mu.m。 6.6。The silica as claimed in claim 1, having a median particle diameter, after deagglomeration under ultrasound, of at most 35 .mu.m.白碳黑做的如权利要求1所声称,有一个平均粒径、 deagglomeration后应用超声引导下,最多35 .mu.m。 7.7。The silica as claimed in claim 1, having a BET specific surface such that the BET-CTAB difference is at most 30 m.sup.2/g.白碳黑做的如权利要求1所,有BET比表面的区别是 BET-CTAB 30 m.sup.2最多。/ g 8.8。The silica as claimed in claim 1, having a packing density of at most 0.3 g/ml.白碳黑做的如 权利要求1所,有堆积密度号最多0.3曼梯?里。 9.9。The silica as claimed in claim 1, in the form of a powder.白碳黑做的如权利要求1所形成的 粉末。 10.10。A process for the preparation of a silica as claimed in claim 1, comprising the following stages: (a) producing a starting vessel heel with a temperature of between 80 and 100.degree.一个 过程白碳黑做的准备工作,包括如权利要求1所以下阶段:(一)生产开始容器脚跟,80% 100.degree之间的温度。C., comprising water and a silicate, with a concentration of silicate in said vessel heel, expressed as SiO.sub.2 equivalent, being less than or equal to 15 g/l; (b) adding, at a temperature of between 80 and 100.degree.由之硅酸盐、水分和一种比较集中的硅酸盐在该 船跟表示,作为SiO.sub.2相同的,是小于或等于15总帐;(二)温度在增加,100.degree 80之间。C., an acidifying agent to bring the pH of the medium to a value of between 7 and 8, to form a medium; (c) in the medium thus produced in stage (b), carrying out, at a temperature of between 80 and 100.degree.一个acidifying代理人之带来的酸碱度中价值7至8点间,构成中;(三)中这样 产生了在舞台(b),开展、高温中80% 100.degree之间。C., a simultaneous addition of a silicate and of an acidifying agent, with a respective amounts of silicate and of acidifying agent added over time being specifically chosen so that, throughout the duration of the addition: the pH of the reaction medium remains between 7 and 8 and optionally between 7.2 and 7.8; and the concentration of silicon in the medium, expressed as SiO.sub.2 equivalent, remains less than or equal to 35 g/l; (d) adding, at a temperature of between 80 and 100.degree.同时之增加硅酸盐和 一个acidifying代理,各自的大量的硅酸盐和增加acidifying剂的选择被明确,在整个使用期间 另:的酸碱度反应介质7、8间依然存在,并选择720 7.8,之间浓度的硅中表示,作为SiO.sub.2相 同的,仍然是小于或等于35总帐;(d)增加、高温中80% 100.degree之间。C., an acidifying agent to the medium obtained on conclusion of stage (c) so as to bring the medium to a pH of between 3 and 6.5 to obtain an aqueous silica dispersion; (e) filtering the aqueous silica dispersion obtained in stage (d) in order to obtain a filtration cake; (f) drying the filtration cake produced on conclusion of the stage (e), optionally washing it beforehand; and (g) optionally milling or micronizing the silica obtained on conclusion of stage (f); wherein as a result of the process the filtration cake exhibits, prior to the drying of it in stage (f), a loss on ignition at 1000.degree.一个 acidifying代理人之中获得结论舞台(c),带介质的酸碱度和3之间获得水6.5%到硅散布,(e)过滤 水分散了白炭黑在舞台(d)以取得滤饼、(f)干燥过滤蛋糕由结论的舞台(e),可事先清洗;(g)的 micronizing铣削或可获得结论硅阶段(f)。其中作为一个过程结果的过滤蛋糕展览,在干燥的 阶段(层),损失点火在1000.degree。C. of greater than 82%.更大的比之82%。 11.11分。Shoe soles comprising the silica as defined in claim 1.由底鞋如权利要求1所定义的白 炭黑。 12.12。A matrix based on silicone(s) comprising the silica as defined in claim 1 as reinforcing filler.在一个基于矩阵组成的有机硅(s)如权利要求1所定义的白炭黑填充等。 13.13岁。A carrier for liquids comprising the silica as defined in claim 1.包括了液体载体如权利 要求1所定义的白炭黑。 14.14。A dentifrice composition in the paste or gel form comprising the silica as defined in claim 1 as a thickening agent.一个牙膏构成粘贴或凝胶形式包括如权利要求1所定义的白炭黑作为增 稠剂。 15.15。Battery separators comprising the silica as defined in claim 1.硅电池分离器组成的如权利 要求1所定义的。 16.16岁。The precipitated silica according to claim 1, wherein the water uptake is greater than 3%.根据权利要求沉淀法二氧化硅的1,其中的水分吸收大于3%。 17.17日。The precipitated silica according to claim 5, wherein the mean particle size or median particle diameter is 5 to 15 .mu.m.根据权利要求沉淀法二氧化硅的5个,其中所述意味着颗粒粒 径或中位数是5到15个.mu.m。 18.18岁。The precipitated silica according to claim 17, wherein the mean particle size or median particle diameter is 8 to 13 .mu.m.根据权利要求沉淀法二氧化硅的17个,其中所述平均粒径偏 小、中值粒径为8至13 .mu.m。 19.19岁。The precipitated silica according to claim 6, wherein the median particle diameter, after deagglomeration under ultrasound, is at most 25 .mu.m.根据权利要求沉淀法二氧化硅的6个,其 中所述中值粒径、deagglomeration后应用超声引导下,至多25 .mu.m。 20.20。The precipitated silica according to claim 7, wherein the BET-CTAB difference is at most 10 m.sup.2/g .根据权利要求沉淀法二氧化硅的7个,其中所述BET-CTAB差异最长不得超过10 m.sup.2 /克。 21.21岁。The precipitated silica according to claim 8, wherein the packing density is 0.04 to 0.3 g/ml.根据权利要求沉淀法二氧化硅的堆积密度,其中的8号到0.3夺冠是曼梯?里。 22.22个。The precipitated silica according to claim 10, wherein the temperature in stage (a) is greater than or equal to 90.degree.根据权利要求沉淀法二氧化硅的10个,其中所述温度在阶段 (一)大于等于90.degree。C.C。 23.23日。The precipitated silica according to claim 10, wherein the temperature in stage (b) is 90 to 100.degree.根据权利要求沉淀法二氧化硅的10个,其中所述温度在阶段(b)是90到 100.degree。C.C。 24.24岁。The precipitated silica according to claim 10, wherein the pH in stage (b) is 7.3 to 7.7.根据权利要求沉淀法二氧化硅的10个,其中所述pH值阶段(b)是7.3至7.7。 25.25。The precipitated silica according to claim 10, wherein the temperature in stage (c) is 90 to 100.degree.根据权利要求沉淀法二氧化硅的10个,其中所述温度在阶段(c)是90到100.degree。 C.C。 26.26岁。The precipitated silica according to claim 10, wherein the temperature in stage (d) is 90 to 100.degree.根据权利要求沉淀法二氧化硅的10个,其中所述温度在阶段(d)是100.degree 90。 C.C。 27.27岁。The precipitated silica according to claim 10, wherein the loss on ignition and 1000.degree.根据权利要求沉淀法二氧化硅的10个,其中损失点火和1000.degree。C. is 84 to 88%.c相当于84到88%之间。 28.28日。The precipitated silica according to claim 1, wherein the DOP oil uptake is greater than 310 ml/100 g.根据权利要求沉淀法二氧化硅的1,其中所述DOP石油吸收比310毫升/ 100克。 29.29。The precipitated silica according to claim 10, wherein the loss on ignition and 1000.degree.根据权利要求沉淀法二氧化硅的10个,其中损失点火和1000.degree。C. is greater than 84%.c 比为84%。 30.30岁。A precipitated silica comprising: a CTAB specific surface of 140 to 230 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, a water uptake of less than 6%, a pH of 3.5 to 7.5, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, and a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm.一个沉淀法二氧化硅 包括:一个溴化十六烷三甲基铵的比表面积等140到230 m.sup.2 / g,吸收大于DOP油300毫升/ 100克,水资源量的少于6%,酸碱度的3.5至7.5,剩余的水平负离子,表示为盐,小于或等于2%,和 一个平均粒径偏小或中值粒径之间的30 .mu.m和20毫米。 Description描述 This application is an application under 35 U.S.C. Section 371 of International Application Number PCT/FR2004/003313 filed on Dec. 20, 2004.这个应用程序是一份申请35岁以下部分 登上国际申请编号371名PCT / FR2004/003313 12申请20,2004年。 The present invention relates to a novel highly-structured precipitated silica having a low water uptake and to a process for the preparation of said silica.本发明讲述了一种较为低下了沉淀法 白炭黑highly-structured水分吸收和一个过程制备说二氧化硅。 It also relates to its use as reinforcing filler in matrices based on elastomers, in particular clear or semi-clear elastomers, for shoe soles or in silicon matrices, for example intended for the coating of electric cables.这,,涉及到加强它作为填料矩阵,特别是基于液晶弹性体,无色或semi-clear底 鞋或硅矩阵,例如用于电力电缆涂料。 It also relates to its use in particular as filler and/or carrier and/or excipient in various compositions, such as food, cosmetic or pharmaceutical compositions, compositions for the manufacture of paints or paper, or compositions intended for the manufacture of separating porous membranes for batteries (battery separators), or as thickener agent in dentifrice formulations.这也 涉及到使用特别是填料和/或载体和/或赋形剂在不同的作品,例如食品、化妆品或药物成分、 成分用于制造的油漆或纸,或成分用于制造的分离微孔膜电池(电池分隔符),或者像增稠剂代 理的牙膏载体。 "Precipitated" silicas often exhibit a high affinity for water due in particular to the presence at their surface of water-greedy Si--OH groups.“沉淀”重点显示了一种经常对水由于高亲和力的 尤其表面出现在他们water-greedy斯——噢组。The commonest precipitated silicas generally exhibit water uptakes (according to the test defined below) of greater than 7%, generally of the order of 8 to 10%.最常见的沉淀一般重点展示水吸收(根据测试定义下),通常比7%的顺序的8 - 10%。 A process for preparing a precipitated silica having a low water uptake (of the order of 4 to 6%) forms the subject matter of application WO 03/055801; the silica then obtained generally exhibits a CTAB specific surface (external surface) of 100 to 200 m.sup.2/g and a DOP oil uptake of 150 to 300 ml/100 g; it is indicated that this silica can be used for the reinforcing of silicone-based elastomeric matrices, in particular room temperature or high temperature vulcanizable silicone matrices, or of transparent or translucent elastomeric matrices for shoe soles; it is also mentioned that this silica can also be used as thickening agent in organic or aqueous media, in particular toothpastes.准备一个过程较为低下了沉淀法白炭黑水分吸收(为4至6%)的方式应用的题材, 我们03/055801通常可获得展示了一种硅的比表面积溴化十六烷三甲基铵(外部表面)100 ~ 200 m.sup.2 / g和DOP油量的150 - 300毫升/ 100克;它是表明本硅可用于钢筋silicone-based 弹性矩阵的,尤其是室温或高温vulcanizable硅矩阵,或透明或半透明的弹性矩阵在鞋鞋底,也 是说这硅也能用于增稠剂在有机或水介质,尤其是牙膏。 Highly structured precipitated silicas exhibiting a DOP oil uptake of greater than 250 ml/100 g, in particular of the order of 300 to 320 ml/100 g, and a CTAB specific surface (external surface) of 70 to 250 m.sup.2/g have already been provided as thickening or texturing agent in dentifrice compositions (application WO 01/93803); such silicas exhibit a water uptake of greater than 7%, that is to say conventional for precipitated silicas.高度结构DOP展示重点沉淀石油量的大于 250毫升/ 100克的订单,特别是在300到320毫升/ 100克、溴化十六烷三甲基铵的比表面积 等(外部表面)70到250 m.sup.2 / g已经作为增厚或材质代理01/93803牙膏成分(应用占用了 我们的时间),有重点的水分吸收比7%,也就是说传统重点为沉淀。 The Applicant has now found a novel precipitated silica which exhibits good dispersing performances in formulation and which advantageously exhibits a high dispersibility in various solid, in particular elastomeric (clear, semi-clear, silicone), or pasty matrices or media, and in even a high light transmission.申请人已经找到了小说沉淀法二氧化硅显示出良好的分散性能,配方 中,展示了一种高分散性皆在各种固体,尤其是弹性(清楚,semi-clear、有机硅),或馅饼矩阵,在 媒体甚至高光的传播。This is reflected in particular by a good reinforcing and/or thickening power.这反映尤其是通过良好的加强和/或增厚的力量。This silica is particularly suitable for being employed especially as reinforcing filler in matrices based on elastomers, for example clear or semi-clear elastomers, for shoe soles or in silicone matrices, for example room temperature or high temperature vulcanizable silicone matrices.这硅是特别适合于聘用时,特别是加强填料矩 阵液晶基础上,例如透明或semi-clear弹性体,或在硅矩阵底鞋,例如常温和高温vulcanizable 硅矩阵。A particularly advantageous application of this silica consists, inter alia, of its use as thickening agent in dentifrices formulations.一个特别有利的硅的应用,包括采信增稠剂的应用 在牙膏、牙粉载体。 A first subject matter of the invention consists of a precipitated silica exhibiting: a CTAB specific surface of 140 to 230 m.sup.2/g, preferably of 145 to 195 m.sup.2/g, more preferably of 145 to 185 m.sup.2/g, very particularly of 150 to 185 m.sup.2/g, in particular of 150 to 180 m.sup.2/g, for example of 155 to 175 m.sup.2/g or of 160 to 180 m.sup.2/g, a DOP oil uptake of greater than 300 ml/100 g, preferably of greater than 310 ml/100 g, more preferably of 315 to 450 ml/100 g, very particularly of 320 to 400 ml/100 g, in particular of 340 to 380 ml/100 g, a water uptake of less than 6% and preferably of greater than 3%, very particularly of greater than or equal to 4% and of less than or equal to 5.8%, a pH of 3.5 to 7.5, preferably of 4 to 7, very particularly of 4 to 6, a level of residual anion, expressed as sodium sulfate, of less than or equal to 2%, preferably of less than or equal to 1.5%, particularly of less than or equal to 1% and very particularly of less than or equal to 0.5%, a mean particle size or a median particle diameter of less than 30 .mu.m or of between 30 .mu.m and 20 mm.第一个标的的发明包括一个沉淀法二氧化硅展示:溴化十六烷 三甲基铵的比表面积等140到230 m.sup.2 / g,最好是145到195 m.sup.2 / g,更多的最好145 改为185 m.sup.2 / g,非常尤其是150 - 185 m.sup.2 / g,尤其是150到180 m.sup.2 / g,例如155 调整为175 m.sup.2 / g或160至180 m.sup.2 / g,吸收大于DOP油300毫升/ 100克,特别是对 超过310毫升/ 100克,更多的最好3.15 450毫升/ 100克,非常特别320 400毫升/ 100克,尤其 是340 - 380毫升/ 100克,水资源量的少于6%,特别是对大于3%,非常尤其是大于等于4%和 小于或等于5.8%酸碱度,3.5至7.5,特别是对4到7,非常特别4 - 6,等级残留的负离子,表示为 盐,小于或等于2%,特别是对小于或等于1.5%,尤其是小于或等于1%,非常尤其是小于或等于 0.5%,平均粒度或平均粒径小于30 .mu.m或30到.mu.m和20毫米。 According to a first alternative form of the invention, the silica exhibits a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m.根据一项第一种形式的这项发明, 展示了一种硅平均粒径偏小或平均粒径小于30 .mu.m,特别是对不到20 .mu.m,尤其是在5和 15 .mu.m,尤其是长达8 - 13 .mu.m。 According to a second alternative form of the invention, the silica exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm.根据一项第二种形式的这项发明, 展示了一种硅平均粒径偏小或中值粒径之间的30 .mu.m和20毫米。 The silica according to this second alternative form of the invention very preferably exhibits a CTAB specific surface of 145 to 185 m.sup.2/g, in particular of 150 to 180 m.sup.2/g, very particularly of 155 to 175 m.sup.2/g.硅的根据本第二种形式的这项发明很最好表现出溴化十 六烷三甲基铵的比表面积等145改为185 m.sup.2 / g,尤其是150到180 m.sup.2 / g,非常尤其 是155调整为175 m.sup.2 /克。 The CTAB specific surface is the external surface determined according to standard NFT 45-007 (November 1987).溴化十六烷三甲基铵具体表面的外表面按照标准非功能性测试 45-007(1987年11月)。 The DOP oil uptake is determined according to standard ISO 787/5, dioctyl phthalate being employed.吸收DOP油的决定根据标准ISO 787/5,dioctyl被录用酞酸酯类化合物。 The affinity of a silica with regard to water, expressed by its "water uptake" characteristic, reflects the more or less marked tendency which water molecules exhibit of being adsorbed on the surface of silica.亲和力的二氧化硅关于水,表达其“水吸收”的特点,反映出显著的倾向或多或少的水 分子被展出,白炭黑表面吸附于。 The principle of the test for measuring this characteristic consists in placing the predried sample of silica under given relative humidity conditions for a predefined period of time; the silica hydrates, which causes the weight of the sample to change from a starting value w (in the dried state) to a final value (w+dw).测验的原则测量这一特点在于把predried样品在给定相对湿度条件硅预定 一段时间;硅水合物的重量,使样品转一个初始值w(干的状态下)最后一个值(w + dw)。"Water uptake" of a silica will specifically denote the dw/w ratio, expressed as percentage, calculated for a silica sample subjected to the following conditions during the test: preliminary drying: 8 hours at 105.degree.“水吸收硅”指将具体dw / w比率,表示为的百分比,计算出一个硅样品需要具备一 定的条件下在测试:初步干燥:在105.degree 8个小时。C.; hydration: 24 hours at 20.degree.c;水 化:24小时在20.degree。C. under a relative humidity of 70%.相对湿度下之70%。 The experimental protocol employed consists in: exactly weighing approximately 2 g of the test silica; drying the silica thus weighed for 8 hours in an oven adjusted to a temperature of 105.degree.实验协议完全在于:采用重约2克测试硅;烘干硅因此重8小时在炉子里105.degree 调整到温度。C.; determining the weight w of the dried silica obtained on conclusion of the drying operation; placing the dried silica obtained in a closed container (for example in a desiccator) containing a water/glycerol mixture with a water/glycerol ratio by weight of 35/65, so that the relative humidity of the closed medium is 70%, for 24 hours at 20.degree.c;确定权重w的硅干了 干燥的操作结束了,把乾白炭黑在一个密闭的容器(例如在干燥机)含有水/甘油混合水/甘油比 35/65的重量,所以相对湿度封闭的70%,媒体是在20.degree 24小时。C.; determining the weight (w+dw) or the silica obtained subsequent to this treatment for 24 hours at 70% relative humidity, this weight being measured immediately after having removed the silica from the desiccator, so as to avoid a variation in the weight of the silica under the influence of the change in hygrometry between the medium at 70% relative humidity and the atmosphere of the laboratory.c;确定权重(w + dw)或获得治疗硅随后24小时,其重量相对湿度70%被测硅去吃完从干燥机,以避免变化对 硅的重量的影响下hygrometry的变化之间的相对湿度70%介质,气氛实验室。 The pH of the silica is measured according to standard ISO 787/9 (pH of a 5% by weight suspension of silica in deionized water).白炭黑的酸碱度按照标准ISO测量787/9(pH的5%(重 量白炭黑在去离子水暂停)。 The silica according to the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of a powder having a mean particle size or a median particle diameter of at most 20 mm.依本发明的硅则可以珠子的形式,颗粒(或其他蕴)或粉末,最好是有一个平均 粒径偏小或中值粒径最多20毫米。 The silica according to the first alternative form of the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of a powder having a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m.硅的根据第一种形式的这项发明, 则可以珠子的形式,颗粒(或其他蕴)或粉末,最好是有一个平均粒径偏小或中值粒径小于 30 .mu.m,特别是对不到20 .mu.m,尤其是在5和15 .mu.m,尤其是长达8 - 13 .mu.m。This silica is particularly suitable for being employed as reinforcing filler in matrices based on elastomer(s), in particular clear or semi-clear elastomer(s), for shoe soles or as reinforcing filler in matrices based on silicone(s).这硅是特别适合于使用矩阵填料等基于弹性体(s),尤其是透明或 semi-clear弹性体(s),底鞋或加强填料矩阵基于硅(s)。 The silica according to the second alternative form of the invention can be provided in the form of beads, of granules (or other aggregates) or, preferably, of powder having a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm.硅的依照第二个种形式的这项发明, 则可以珠子的形式,颗粒(或其他)或聚集的粉末,最好是有一个平均粒径偏小或中值粒径之间 的30 .mu.m和20毫米。It can in particular be a powder exhibiting a median particle diameter of at least 30 .mu.m, preferably of at least 50 .mu.m, and of less than 350 .mu.m, preferably of less than 180 .mu.m; this silica is particularly suitable for being used as thickening or texturing agent in dentifrice compositions or as reinforcing filler in matrices based on silicone(s).它可以在特定 的是一个粉展示了中值粒径至少3000 .mu.m,特别是对至少50 .mu.m,不超过350 .mu.m,特别 是对不到180 .mu.m;这硅是特别适合于作为增厚或贴图成分或牙膏代理等填料矩阵基于硅 (s)。 The silica can also concern granules (or other aggregates) exhibiting a mean particle size of between 2 and 20 mm.硅也可以关注的颗粒(或其他蕴)展示平均粒度对2 - 20毫米。 The mean size of the silica particles can be determined according to standard NF X 11507 (December 1970) by dry sieving and determining the diameter corresponding to a cumulative oversize of 50%.平均的大小可以确定硅粒子按照标准NF X 11507(12月1970)干燥筛选、确 定对应于一个直径累积特大型50%。 The median diameter of the silica particles can be determined by laser diffraction according to standard NF X 11-666.白炭黑的平均直径粒子激光衍射确定按照标准NF X 11-666。The particle sizer used is of the Malvern Mastersizer type.使用粒度仪的Mastersizer贵国的类型。 Measurement Criteria optical concentration: 12.+-.2% measurement liquid: degassed demineralized water absence of ultrasound absence of dispersant duration of the measurement: 10 seconds测量标准光学专注:12。每升1级+ -.2%测量液体。degassed软化水缺乏超声缺乏分 散剂的持续时间测量:10秒 The precipitated silica according to the invention generally exhibits a median diameter d50 of the particles, after deagglomeration under ultrasound, of at most 35 .mu.m, preferably of at most 30 .mu.m, very particularly of at most 25 .mu.m, in particular of at most 15 .mu.m, for example of at most 10 .mu.m.沉淀白炭黑的一般依本发明第一张摄影作品中值粒径展示了一种颗粒的 deagglomeration后,应用超声引导下,最多35 .mu.m,最好最多30 .mu.m,非常特别最多 25 .mu.m,尤其是最多15 .mu.m,例如最多10 .mu.m。 The median diameter d50 of the silica after deagglomeration under ultrasound is measured using the Malvern Mastersizer particle sizer according to the following test:我的第一张摄影作品中值 粒径的硅的测量应用超声引导下deagglomeration后使用贵国粒度仪Mastersizer根据以下测 试: The power of the ultrasound in the Malvern Mastersizer particle sizer being adjusted to the maximum graduation of 20, an amount of silica is introduced so as to obtain an optical concentration of 12.+-.2%.权力的超声在贵国调整后粒度仪Mastersizer最大毕业的20,相当于 介绍了白炭黑的,得到一种浓度的12。每升1级+ -.2%。 The median diameter d50 and the percentage of silica particles with a diameter of greater than 51 .mu.m are measured after having kept the vessel subjected to ultrasound for 60 seconds, the vessel being homogenized by circulation of the suspension using a centrifugal pump.我的第一张 摄影作品中值粒径的粒子白炭黑的百分比,直径大于51 .mu.m测量让船后受到60秒,超声船 舶被流通”以同质性悬架用离心泵。The measurement is recorded 10 seconds after ceasing to apply ultrasound.测量10秒后,停止应用超声检查。 The ability of the silica according to the invention to disperse or to deagglomerate can also be assessed by a particle size measurement (by laser diffraction) carried out on a suspension of silica deagglomerated beforehand by ultrasonication (splitting of the objects from 0.1 to a few tens of microns).硅的能力去驱散依本发明或deagglomerate也可以经过颗粒粒径测定(激光衍射)进 行deagglomerated悬浮的硅3:18 ultrasonication(分裂的对象从0.1至数十微米)。The deagglomeration under ultrasound is carried out using a Vibracell Bioblock (600 W) ultrasound generator equipped with a probe with a diameter of 19 mm.deagglomeration的应用超声引导下 进行一个Vibracell Bioblock(600 W)超声发电机配备了探头直径19毫米。The particle size measurement is carried out by laser diffraction on a Sympatec particle sizer.粒度测量进行了在激 光衍射Sympatec粒度仪。 2 grams of silica are weighed out into a sample tube (height: 6 cm and diameter: 4 cm) and are made up to 50 grams by addition of deionized water: a 4% aqueous silica suspension is thus produced and is homogenized for 2 minutes with magnetic stirring.两公克的二氧化硅重到样品 管(高度:6厘米,直径为4厘米),决定了要50克添加含去离子水水:硅悬挂4%,就这样产生了均 质两分钟磁性的悸动。Deagglomeration is subsequently carried out under ultrasound as follows: the probe being immersed over a length of 4 cm, the output power is adjusted so as to obtain a deviation of the needle of the power dial indicating 20%.随后Deagglomeration应用超声引导下 进行如下:探测器沉浸在一段4公分,输出功率调整,才能获得偏差电力拨针表示20%。 Deagglomeration is carried out for 420 seconds.Deagglomeration执行为420秒。The particle size measurement is subsequently carried out by introducing, into the vessel or the particle sizer, a volume V (expressed in ml) of the homogenized suspension necessary in order to obtain an optical density of the order of 20.随后的粒度检测进行了介绍,到船只或者粒度仪、卷V(以毫升)的悬 架同质性的先后顺序,以获得一种光密度20的次序。 A deagglomeration factor F.sub.D is then given by the equation: F.sub.D=10.times.V/optical density of the suspension measured by the particle sizer (this optical density is of the order of 20).一个deagglomeration因素被赋予了F.sub.D方程的F.sub.D = 10.times.V /光密度测量中止粒 度仪(这光密度为20)。 This deagglomeration factor F.sub.D is indicative of the level of particles with a size of less than 0.1 .mu.m which are not detected by the particle sizer.这deagglomeration因素象征F.sub.D粒子 与水平的尺寸小于0.1 .mu.m不是粒度仪能探测到的。This factor increases as the silica exhibits an increased aptitude for deagglomeration.这个因素随著硅展品增加deagglomeration资质。 The value of the median diameter d50which is obtained according to this test decreases as the silica exhibits an increased aptitude for deagglomeration.中值粒径的价值得到d50which根据这 个测试会随硅展品增加deagglomeration资质。 Preferably, the silica according to the invention has a median diameter d50, after deagglomeration under ultrasound, of less than 6 .mu.m, in particular of less than 5 .mu.m, for example of less than 3.5 .mu.m.硅较有依本发明中值粒径的第一张摄影作品,在deagglomeration应用超声引导下, 不超过6 .mu.m尤其是少于5 .mu.m,例如小于3.5 .mu.m。 The silica according to the invention generally exhibits an ultrasound deagglomeration factor F.sub.D of greater than 5.5 ml, in particular greater than 7.5 ml, for example greater than 11.5 ml.硅依本发明的一套超声deagglomeration因素通常展览的F.sub.D比5.5毫升,尤其是超过750 毫升,例如比11.5曼梯?里。 The silicas according to the invention preferably exhibit a BET specific surface such that the BET-CTAB difference is at most 30 m.sup.2/g, preferably at most 25 m.sup.2/g, more preferably at most 20 m.sup.2/g, in particular at most 10 m.sup.2/g.依本发明的重点最好有BET比表 面,BET-CTAB最多的区别是30 m.sup.2 / g,最好是在最25 m.sup.2 / g,更有20 m.sup.2最多/ g, 尤其是最长不得超过10 m.sup.2 /克。 The BET specific surface is determined according to the Brunauer-Emmett-Teller method described in the Journal of the American Chemical Society, vol. 60, page 309, February 1938, corresponding to standard NFT 45007 (November 1987).赌注的比表面积等取决于 Brunauer-Emmett-Teller方法描述在《美国化学学会60页,第2月1938年,相应309标准非功 能性测试45007(1987年11月)。 Furthermore, the silicas according to the invention generally exhibit a packing density, measured according to standard ISO 787/11, of at most 0.3 g/ml, preferably of 0.04 to 0.3 g/ml, more preferably of 0.05 to 0.3 g/ml, in particular of 0.05 to 0.2 g/ml; this packing density can also be between 0.1 and 0.3 g/ml, in particular between 0.1 and 0.27 g/ml, especially between 0.15 and 20.25 g/ml.此外,依本发明重点通常有堆积密度、测量根据标准ISO 787/11,最多0.3 g / ml,特 别是对0.04到0.3 g / ml,特别是对0.05 ~ 0.3 g / ml,特别是违反0.05 ~ 0.2 g / ml,这堆积密度之 间也可以0.1 ~ 0.3 g / ml,尤其是0.1 ~之间0.27克/ ml,尤其是号之间20.25 0.15,曼梯?里。 The loss on ignition (LOI) of the silica of the invention, measured according to standard ISO 3262/11, after treatment at 1000.degree.损失的点火认为印记缺失的二氧化硅发明、测量根据标 准ISO 3262/11治疗后,1000.degree。C., is generally such that the difference between the LOI and the water content is less than 3.2%, preferably less than 3%, very particularly less than 2.7%.通常 这样之之间的差别和含水量LOI(小于3.2%,最好是少于3%,非常特别不到2.7%。 The water content is the residual water content measured according to standard ISO 787/2, after heat treatment at 105.degree.水的含量测量残留水份含量按照标准ISO 787/2热处理后,在 105.degree。C. for 2 hours.c为2小时。 The water content of the silica according to the invention, in particular when it is intended to be used as filler in silica matrices, is generally less than 5%, preferably less than 4%, for example at most 3%, of the total weight of the sample.硅的含水量依本发明,特别是当它要被用作填料硅矩 阵,一般少于5%,最好是少于4%,比如在大多数3%的总重量的样品。 The silica according to the invention can additionally exhibit a level of transmission of at least 70% at a refractive index in glycerol lying between 1.450 and 1.467.硅的依本发明更可以有水平 的70%以上的传播在折射率在隔1.450和1.467甘油。 The refractive index under consideration is that corresponding to the most transparent suspension (maximum transmission) of this silica in various water-glycerol solutions, which transparency is determined by the transmission at 589 nm with a spectrophotometer.折射指数低于考虑对应于最 透明悬架的最大传输)白炭黑在各种water-glycerol透明度是解决,确定589传动系统,用 分光光度计之。Each suspension is obtained by dispersing 2 g of silica in 18 g of water/glycerol solution and then deaerating under a slight vacuum before reading the transmission (reading carried with the silica-free water/glycerol solution as reference product) on the spectrophotometer and the refractive index on a refractometer.每个悬架分散了2克白炭黑在18克水/甘油解决方案, 然后在轻微的真空排气阅读之前进行传输(阅读与silica-free水/甘油解决方案的参考产品的 折射率,将分光光度管在refractometer。 A second subject matter of the invention consists of a process for the preparation of the highly-structured silica having a low water uptake described above, comprising the following successive stages: (a) producing a starting vessel heel with a temperature of between 80 and 100.degree.第二个标的的发明包括一个过程制备硅highly-structured较为低下上述水分吸收, 包括以下连续阶段:(一)生产开始容器脚跟,80% 100.degree之间的温度。C., preferably of greater than or equal to 90.degree.c,特别是对大于等于90.degree。C., comprising water and a silicate, the concentration of silicate in said vessel heel, expressed as SiO.sub.2 equivalent, being less than or equal to 15 g/l; (b) adding, at a temperature of between 80 and 100.degree.由之水和 硅酸盐、浓度的硅酸盐在该船跟表示,作为SiO.sub.2相同的,是小于或等于15总帐;(二)温度 在增加,100.degree 80之间。C., preferably 90 and 100.degree.100.degree,最好是90和之。C., an acidifying agent to bring the pH of the medium to a value of between 7 and 8, preferably to a value of between 7.2 and 7.8 and advantageously between 7.3 and 7.7 (typically to a value substantially equal to 7.5); (c) in the medium thus produced, carrying out, at a temperature of between 80 and 100.degree.一个acidifying代理人之带来的酸碱度媒体到一个7至8点间的价 值,最好的价值之间的参与和7.8 7.2(通常是和7.7 7.3之间的价值等额到7.5);(三)中,执行了, 这样产生高温中80% 100.degree之间。C., preferably between 90 and 100.degree.有90%之间之 100.degree。C., the simultaneous addition of a silicate and of an acidifying agent, the respective amounts of silicate and of acidifying agent added over time being specifically chosen so that, throughout the duration of the addition: the pH of the reaction medium remains between 7 and 8 and advantageously between 7.2 and 7.8; and the concentration of silicon in the medium, expressed as SiO.sub.2 equivalent, remains less than or equal to 35 g/l; (d) adding, at a temperature of between 80 and 100.degree.同时之增加硅酸盐和一个acidifying剂,各自的大量 的硅酸盐和增加acidifying剂的选择被明确,在整个使用期间另:的酸碱度间依然存在反应介 质7、8和参与,7.8 7.2之间浓度的硅中表示,作为SiO.sub.2相同的,仍然是小于或等于35总 帐;(d)增加、高温中80% 100.degree之间。C., preferably between 90 and 100.degree.有90%之 间之100.degree。C., an acidifying agent to the medium obtained on conclusion of stage (c) so as to bring the medium to a pH of between 3 and 6.5; (e) filtering the aqueous silica dispersion obtained; (f) drying the filtration cake produced on conclusion of the filtration, preferably washing it beforehand; (g) optionally milling or micronizing the silica obtained on conclusion of stage (f), said process being characterized in that the filtration cake exhibits, prior to the drying of it in stage (f), a loss on ignition at 1000.degree.一个acidifying代理人之中获得结论舞台(c),带介质的酸碱 度和3之间6.5;(e)过滤水硅扩散,得到(f)干燥过滤蛋糕上产生过滤的结论,最好事先清洗;(g) 的micronizing铣削或可获得结论硅阶段(f)说,被描述过程,过滤蛋糕展览,在干燥的阶段(层), 损失点火在1000.degree。C. of greater than 82%, preferably of at least 84%, very particularly of 84 to 88%.更大的2001年之,最好至少84%,非常尤其是84 - 88%。 The silicates employed in stages (a) and (c) of the process can be chosen from all the common forms of silicates.硅酸盐用于阶段(a)和(c)款选择过程可以从所有的硅酸盐的共同形式。 Advantageously, the silicates used according to the invention are alkali metal silicates, such as, for example, sodium or potassium silicates.推进,硅酸盐采用这项发明碱金属硅酸盐,,例如钠或钾 硅酸盐。 Particularly preferably, the silicate of stage (a) is a sodium silicate, as well as that added during stage (c).特别是最好、硅酸盐舞台(a)是一个硅酸钠,以及中加入阶段(c)。The sodium silicate employed is then generally characterized by an SiO.sub.2/Na.sub.2O ratio by weight of between 2 and 4, advantageously between 3 and 3.6, this SiO.sub.2/Na.sub.2O ratio by weight preferably being between 3.3 and 3.5 (typically, this ratio is substantially equal to 3.4).然后采用水玻璃的一 般特点是SiO.sub.2 / Na.sub.2O的重量比2 - 4日和3之间劫掠3.6,该SiO.sub.2 / Na.sub.2O 比体重3.3之间有3.5分,是(通常是,这一比例是大体上就相当于第3.4章)。 The vessel heel of stage (a) of the process is generally provided in the form of an aqueous silicate solution, the concentration of which is characteristically less than or equal to 15 g/l.船舶跟舞台 (一)这一过程一般表格内提供解决方案的硅酸盐水、浓度的出现小于或等于15克/升左右。 Typically, the concentration of silicate in the vessel heel of stage (a), expressed as SiO.sub.2 equivalent, is between 1 and 15 g/l.典型的硅酸盐、浓度及船舶的跟舞台(a)表示,作为SiO.sub.2 相同的,是1到15克/升左右。This concentration of silicate in the vessel heel of stage (a), expressed as SiO.sub.2 equivalent, is advantageously less than or equal to 10 g/l and preferably less than or equal to 9 g/l.这个浓度的硅酸盐麽跟舞台(a)表示,作为SiO.sub.2相同的,皆小于或 等于10克/ l,最好是小于或等于9总帐。 The vessel heel of stage (a) generally has a pH of the order of 9 to 13.船舶跟舞台(a)通常pH为9 到13岁不等。 Stage (b) of the process of the invention consists specifically in reducing this value of the pH by addition of an acidifying agent, so as to bring the pH to the medium within the range from 7 to 8, where it has been demonstrated that the reaction for the precipitation of the silica takes place in optimum fashion.阶段(b)过程的具体的发明包括减少这种价值的酸碱度由再加一个acidifying 剂、,实现对媒体的pH值在范围从7到8,在那里已经证明,反应的硅降水发生在最佳的方式。 The term "acidifying agent" is understood to mean any inorganic or organic acidic compound capable of being able to lead to a reduction in the pH of the vessel heel.本法所称acidifying代理 人”被认为是任何酸性无机或有机化合物能够能减少船只的酸碱度脚跟。Thus, use may advantageously be made, as acidifying agent, of an inorganic acid, such as sulfuric acid, hydrochloric acid or nitric acid, or alternatively of an organic acid, such as acetic acid, formic acid or carbonic acid.因此,使用,皆为acidifying代理,无机酸、硫酸、盐酸、硝酸,或干脆的有机酸, 如醋酸、甲酸或碳酸。 Advantageously, no electrolyte is added during the process, in particular in stage (a).推进,没有电 解质加在这一过程中,特别是在阶段(a)。The term of "electrolyte" is to be understood here as normally accepted, that is to say that it denotes any ionic or molecular substance which, when it is in solution, decomposes or dissociates to form ions or charged particles (the usual electrolytes are alkali metal and alkaline earth metal salts, in particular the salt of the starting silicate metal and of the acidifying agent, such as sodium chloride in the case of the reaction of a sodium silicate with hydrochloric acid or sodium sulfate in the case of the reaction of a sodium silicate with sulfuric acid).称电解质”在这里就是了解一般公认的,也就是说,它表示任何离子及分子生物学的物质, 它,当它在溶液中,分解或dissociates形成离子或带电粒子(通常碱金属电解质和碱性地球金属 盐,特别是在启动盐硅酸盐金属和acidifying剂如氯化钠的情况下的反应或用盐酸水玻璃盐 的情况下的反应水玻璃用硫酸)。 The acidifying agent employed in stage (b) of the process is preferably sulfuric acid, in particular when the silicate present in the starting vessel heel is an alkali metal silicate.acidifying剂的应用 于阶段(b)的过程是比较硫酸,特别是当硅酸盐存在于开始跟是船舶碱金属硅酸盐。Generally, the acidifying agent of stage (b) is most often introduced in the form of an aqueous solution, preferably a dilute aqueous solution, generally with a normality of between 0.25 and 8N.一般来 说,acidifying代理阶段(b)是最常被介绍的形式,最好是水溶液稀溶液,一般用一种常态。8N 0.25之间,Thus, in stage (b), the reduction in the pH of the medium can advantageously be carried out by addition of an aqueous sulfuric acid solution with a concentration of between 10 and 350 g/l and preferably between 50 and 250 g/l.因此,在阶段(b),减少的酸碱度劫掠介质可以增加进 行水硫酸解集10到350总帐,最好,50至250克/升左右。 Whatever the exact nature of the acidifying agent of stage (b), this acidifying agent must be employed so that its addition results in the reduction in the pH of the medium down to a value of between 7 and 8.不管的确切性质acidifying代理的舞台(b),该acidifying代理,我们应该使用它 的增加导致减少的酸碱度中到7至8点间的价值。The amount of acidifying agent to be employed in this context is generally determined in practice by measuring the change in the pH during the addition, the addition of the acidifying agent of stage (b) being continued until the pH reaches the desired value.acidifying代理的数量被聘用决定在此背景下,通常是在实践中通过 测量的pH值的变化在加法,再加上另外的acidifying代理阶段(b)在继续,直到pH达到预期的 价值。 Furthermore, the addition of stage (b) is preferably carried out gradually, that is to say advantageously, as a general rule, with an addition time of between 3 and 60 minutes, generally at least equal to 5 minutes and preferably at least equal to 10 minutes.此外,加入的阶段(b)优先考虑 实施逐渐地,也就是说推进作为一般规则,它带有一个附加和3之间的60分钟,一般至少与5 分钟,最好至少相当于10分钟。However, this addition time is advantageously less than 30 minutes.然而,这除了时间皆不超过30分钟。 According to a specific embodiment which can be envisaged for stage (b), this stage can include a maturing process which, if appropriate, is carried out by leaving the medium to change for a period of time generally of between 5 and 30 minutes, preferably at a temperature of between 90 and 100.degree.根据一项具体体现,可以设想舞台(b),这个阶段的过程可以包括成熟,如果正确, 进行了离开中改变一段时间一般在5,最好是30分钟温度在100.degree 90%之间。C., it being understood that, subsequent to this maturing, the pH of the reaction medium is adjusted if necessary, in particular by addition of an acidifying agent, so that, on conclusion of stage (b), the pH of the medium lies within the pH range between 7 and 8 and advantageously within the abovementioned preferred ranges.它是之明白,同时,成熟,pH的反应中调整如有必要,尤其是通 过再加一个acidifying剂,从而在结论舞台(b),pH值属于介质的7至8点间酸碱度范围内生长 的正好在上述所提到的首选,范围。 Subsequent to stage (b), by which the pH of the reaction medium is brought within the preferred region from 7 to 8 and preferably to approximately 7.5, stage (c) of the process consists in continuing the process for the precipitation of silica by introducing additional silicate and by specifically maintaining the pH of the medium within the region between 7 and 8, preferably at a substantially constant value, this constant value then preferably being close to 7.5, that is to say generally between 7.3 and 7.7.以后的阶段(b),反应的酸碱度囊括在介质的首选地区7到8,最好 是大约7.5、舞台(c)款,继续的过程包括降水过程由白炭黑的引入额外硅酸盐和由专门维护中 酸度的区域内7至8点间,最好是在一个本质上定值,该定值,然后最好接近7.5,也就是说一般 在7.3和7.7。 To do this, the silicate of stage (c) is introduced in conjunction with an acidifying agent which opposes the increase in pH which would be observed by adding the silicate alone.为了做到这一 点,硅酸盐舞台(c)介绍结合一个acidifying剂反对增加可以观察的pH值,通过增加硅酸盐孤 独。Preferably, stage (c) of the process of the invention is carried out immediately after obtaining, for the medium, the desired pH in stage (b).如果有可能的话,阶段(c)款发明的过程进行了获取、 后立即中,你想要的pH值阶段(b)。The "simultaneous addition" of the silicate and of the acidifying agent which is carried out during stage (c) advantageously consists of a continuous addition of silicate to the medium, during which the pH of the medium is measured and during which the value of this pH is regulated by introduction of the acidifying agent, it being possible, for example, for this introduction of the acidifying agent to be carried out as soon as the pH of the medium becomes greater than a control value of between 7 and 8, this control value generally being set in a vicinity of 7.5.“同时除"的硅酸盐和acidifying代理过程中进行的是参与阶段(c) 由一个连续的加硅酸盐给媒体,在此期间的酸碱度测量介质,在此期间的价值的酸碱值应该是 受引进的acidifying代理,它是可行,例如,因为这介绍进行acidifying代理,尽快介质pH值越高, 控制价值比7至8点间,该控制阀门通常被设置在一个地区的为7.5。By this means, success is achieved in maintaining, in the medium, a substantial constant value of the pH, that is to say advantageously varying to +/-0.2 pH unit (preferably to +/-0.1 pH unit) around a set value, generally of between 7.3 and 7.7.用这种方法,成功是在维护,中,也会有相当恒定值的酸碱度,也 就是说参与到+ / -0.2 pH值不同单位(最好是+ / - 0.1 pH单位)在设定值,一般在7.3和7.7。 Alternatively, the simultaneous addition of stage (c) can also consist of a continuous addition of acidifying agent to the medium, the pH then being regulated during the addition by introduction of the silicate, it being possible here again for this introduction with the silicates to be, for example, carried out as soon as the pH of the medium becomes less than a control value of between 7 and 8 generally fixed in the vicinity of 7.5.另外,同时增加阶段(c)也可以由一个连续增加acidifying代 理给媒体的pH然后受管制在增加的引入也会在这里硅酸盐、可能回来外引与硅酸盐,例如, 尽快进行的酸碱度不到一控制中成为7至8点间的价值一般固定的误判为7.5。By this means, success is also achieved in keeping the medium at a substantially constant pH, that is to say advantageously varying to +/-0.2 pH unit (preferably to +/-0.1 pH unit) around a set value generally between 7.3 and 7.7.用这种方法,? ?,成功就是也达到了在保持介质实质性的不断pH 值,也就是说参与到+ / -0.2 pH值不同单位(最好是+ / - 0.1 pH单位)之间在价值和7.7 7.3一 般。 According to yet another embodiment which can be envisaged, the simultaneous addition of stage (c) can also consist of a continuous addition both of acidifying agent and of silicate with concentrations and flow rates calculated so that, throughout the duration of the addition, the pH of the medium remains between 7 and 8 and preferably between 7.2 and 7.8.根据另一个化身,换句 话说,可以同时增加阶段(c)也可以由一个连续增加acidifying剂和两种的硅酸盐和浓度和流 动速率计算,在整个使用期间,而且,pH值间依然存在介质的7号和8号之间,最好720和7.8 级。In this case, the pH of the medium generally has a tendency to change during stage (c) or remaining within the abovementioned range but it can, in some cases, remain substantially equal to a constant value advantageously of the order of 7.5.在这种情况下,pH值中通常改变趋势在阶 段(c)或剩余上述范围内,但它可以,在某些情况下,保持等额一固定值顺序的皆为7.5。In this context, it is generally preferable for, throughout stage (c), the instantaneous flow rates corresponding to the amount of silicate functional groups (expressed as molar equivalent of NaOH) introduced per second (recorded as d.sub.s) and the amount of acid functional groups (as moles) introduced per second (recorded as d.sub.A) to be such that the ratio d.sub.S/d.sub.A remains continuously between 1.01 and 1.09 and preferably between 1.02 and 1.07.在此背景下,一般人都 受过,始终阶段(中)、瞬时流动速率与减少的硅酸盐官能团磨牙(表示为相当于氢氧化钠)推出 (每秒的记录,d.sub.s)以及大量的酸官能团介绍(摩尔的记录,每秒钟d.sub.A)应该是这样 的:d.sub.s / d.sub.A比之间,持续之间,最好1.09 1.01 1.02和1.07。 Whatever the exact embodiment of stage (c), the silicate and the acidifying agent used are generally identical to those employed in stages (a) and (b).不管确切的体现阶段(c)、硅酸盐和 acidifying代理使用一般同应用于阶段(a)和(b)。Thus, the silicate of stage (c) is preferably an alkali metal silicate, advantageously a sodium silicate, and the acidifying agent is preferably a strong inorganic acid, generally sulfuric acid.因此,硅酸盐舞台(c)是比较碱性金属硅酸盐、推进 一个硅酸钠,和acidifying代理人是最好是一种强大的无机酸,一般硫酸。 Insofar as, during the simultaneous addition of stage (c), the concentration of silicon in the medium (expressed as SiO.sub.2 equivalent) characteristically has to be kept below or equal to 35 g/l, the silicate introduced into the reaction medium during stage (c) is generally in the form of a dilute aqueous solution, that is to say with a concentration, expressed as SiO.sub.2 equivalent, advantageously of between 10 and 360 g/l, preferably of less than 300 g/l and advantageously of less than 270 g/l, this being very particularly the case when alkali metal silicates, such as sodium silicates, are used.只要,在同时增加阶段(c)、浓度的硅中(表示为特点SiO.sub.2等同必须继续 低于或等于35总帐、硅酸盐引入反应中在阶段(c)是通常的形式,一稀溶液,也就是说为主的 表示,作为SiO.sub.2相同的,正好在10和360总帐,特别是对不到300总帐和推进低于270总 帐,这是很特别的情况在碱金属硅酸盐二氯异氰尿酸钠,硅酸盐,使用。In the same way, the acidifying agent is generally in the form of a dilute aqueous solution which generally has a normality of between 0.25 and 8N and preferably between 0.5 and 4N.在同样的方式,acidifying 代理人是一般形式的水溶液稀释,一般都有一种常态,8N 0.25之间,最好在0.5和1。Thus, in the specific case of the use of an aqueous sulfuric acid solution as acidifying agent of stage (c), for example, the concentration of the solution is advantageously between 25 and 380 g/l and preferably between 50 and 300 g/l.因此,在具体案例使用水硫酸acidifying剂溶液舞台(c),例如、 浓度的解决方案是推进年龄介于25至380总帐,最好,50至300克/升左右。 It should be emphasized that, in view of the use of dilute concentrations in the medium for the precipitation of the silicas, the concentrations of salts in this medium, in particular related to the reaction of the silicate and of the acidifying agent, are characteristically extremely low, which is reflected by a weak ionic strength within the precipitation medium employed.我们必须强调,针对 使用的稀浓度降水的介质盐浓度、重点,特别是中有关硅酸盐和的反应的特点acidifying剂, 极低,这表现在离子强度弱降水中工作。 Without wishing to be committed in any way to a specific theory, it appears possible to hypothesize that the control of the pH and of the concentrations employed makes it possible to minimize the formation of surface SiOH groups.,除非希望致力于在任何一个特殊的理论学说, 看来可能的猜测,控制的酸碱度和浓度使用使人们有可能减少表面形成SiOH组。 So as to further improve the control of the formation of the silica, it is particularly advantageous to carry out the simultaneous addition of stage (c) with silicate and acidifying agent flow rates which are relatively low, that is to say generally with an addition time of stage (c) preferably of between 15 and 300 minutes and preferably between 30 and 100 minutes.以达到进一步提高控制的白炭 黑的形成,它特别有利于增加同时执行阶段(c)硅酸盐和acidifying剂流动速率相对低,也就是 说一般用时间增加了舞台(c)特别是对15至3分钟,最好是30 ~ 100分钟。This is because such addition times generally result in the production of silicon particles exhibiting extremely low levels of surface Si--OH groups.是因为这种增加时间通常会导致硅的生产粒子展示含量很低 的表面是——噢组。 Generally, stage (c) of the process of the invention is carried out with stirring at a temperature of between 80 and 100.degree.一般来说,阶段(c)款发明的过程进行了温度在激动100.degree 80之 间。C. and generally at the same temperature as the addition of stage (b).c和一般在相同温度下, 作为增加阶段(b)。Thus, the operating temperature of stage (c) can advantageously be between 90 and 100.degree.因此,体温阶段(c)之间100.degree 90和参与。C. and it is preferably of the order of 95.degree.c和它是最好95.degree的次序。C. According to a specific alternative form of the process, this applying in particular with regard to the preparation of silicas which can be used in applications other than food, dentifrice, cosmetic or pharmaceutical applications, it is possible to introduce, into the reaction medium, during stage (c), preferably at the end of the stage (that is to say, typically during the period corresponding to the final quarter of this stage, generally during the final 5 to 15 minutes of this stage), an aluminum-based compound, preferably a salt of acidic nature, such as an aluminum sulfate, or alternatively a compound of basic nature, such as a sodium aluminate.根据一项特定之一种替代形式的过程,该理论应用于特定的关于重点的制备方法可 应用于非食物或者药品、化妆品的牙膏,应用程序,就有可能引进、入反应中,在阶段(c),最好 的最后阶段(也就是说,通常是在“十五”期间的最后一季度相应的这个阶段,一般都是在最后 一5到15分钟的这个阶段),一个aluminum-based复合,最好是碱性的盐,如铝盐的化合物,或干 脆的一些基本性质,如钠铝。The amount of aluminum compound introduced in this context is generally such that, within the reaction medium, the Al/SiO.sub.2 ratio is between 0.1 and 1% by weight, this ratio preferably being at most equal to 0.6% and preferably less than or equal to 0.5%.介绍了铝复合的数量在这种情况下,通常是在反应介质、铝/ SiO.sub.2率0.1 ~ 1%之间体重, 这是比最好在大多数等于0.6%,最好是小于或等于0.5%。 Whatever the exact embodiment of stage (c), the reaction medium is, on conclusion of this stage, specifically at a pH of between 7 and 8 and preferably of the order of 7.5.不管确切的体现阶段 (中)、反应中,在我国现阶段的酸碱度,尤其是在7至8点间,最好的次序为7.5。 Depending on the applications envisaged for the silica, stage (d) of acidification of the medium in the pH region from 3 to 6.5 can be varied by the amount of acidifying agent added.根据应用的设 想的硅、舞台(d)中酸化pH地区3 ~ 6.5会因被大量的acidifying经纪人补充道。Preferably, the pH of the medium reached on conclusion of stage (d) is between 3.2 and 5.5.最好的pH中达成结 论舞台(d)是320之间550。 The acidifying agent of stage (d) can without distinction be identical to or different from that or those employed in stages (b) and (c).acidifying代理的舞台(d)可以毫无区别是相同的或是不同 的工作或者分阶段(b)和(c)。Preferably, this acidifying agent of stage (d) is introduced into the medium in the form of an aqueous solution with a normality of between 0.25 and 8N.如果有可能 的话,这acidifying代理阶段(d)引入介质水溶液的形式与一种常态,8N 0.25之间。 Advantageously, it is an aqueous sulfuric acid solution generally at a concentration of between 25 and 380 g/l, if appropriate.推进,是水硫酸溶液的浓度一般年龄介于25岁至380总帐,如果合 适。 The combined stages (a), (b), (c) and (d) of the process are preferably carried out at a temperature of between 90 and 100.degree.联合阶段(一)、(二),(中)和(d)过程中的温度进行了在一个有90% 100.degree之间。C., advantageously at a temperature of between 93 and 97.degree.参与之温度在 1993和之间的97.degree。C. and more advantageously still at a temperature substantially equal to 95.degree.c和更多的推进仍然处于温度大体上就相当于95.degree。C. throughout the process. 整个过程之。 According to an advantageous alternative form of the process of the invention, the aqueous silica dispersions obtained on conclusion of stages (c) and (d) can be subjected to a maturing stage generally carried out, if appropriate, by leaving the medium, preferably with stirring, at a temperature of between 90 and 100.degree.根据一项有利的一种替代形式过程的发明,水硅乳液 获得结论阶段(中)和(d)可以受到成熟阶段一般执行,如果正确,让中,最好有搅拌、温度在 100.degree 90%之间。C. for a period of time which can advantageously be between 15 and 240 minutes and preferably for a period of time of greater than 30 minutes, the temperature during the maturing preferably being substantially constant (if appropriate, advantageously substantially equal to 95.degree.在一段时间内之可推进是15至240分钟,最好是为一段时间的大于30分钟, 温度在成熟最好被大大常数(如果适宜的话,推进大体上就相当于95.degree。C.) or else increasing (generally stepwise, if appropriate) within the temperature range extending from 90 to 100.degree.c)否则增(一般逐步如果适宜的话,温度范围内延伸至90到100.degree。C.C。 It should be emphasized that the addition of an aluminum compound, in particular of aluminum sulfate type, which can be envisaged at the end of stage (c) can also be carried out during stage (d) or alternatively during the subsequent maturing stage, when this stage is carried out.应该强调,再 加一个铝复合,特别是铝硫酸盐型两种类型,可以设想的最后阶段(c)也可以进行在阶段(d)也 在后来的成熟阶段,这个阶段执行。Thus, generally, this addition of an aluminum-based compound to the medium can take place between stage (c) and stage (e).因此,一般来说,这个再加 一个aluminum-based复合给媒体之间能够进行阶段(中)和阶段(e)。 Stages (e) and (f) of the process consist overall in recovering a silica in the solid form from the dispersion obtained on conclusion of the preceding stages.阶段(e)和(f)的过程包括恢复了总体上 白炭黑在坚实的形式由色散获得结论前阶段。 Generally, during this stage (e), the dispersion obtained on conclusion of stage (d) and of the optional subsequent maturing stage is filtered through a filter press or is filtered under vacuum using a rotary filter, a belt filter or a flat filter, this filtration resulting in a "silica cake" being obtained.一般来说,在这个时期(e),色散获得结论舞台(d)和随后的成熟阶段是可选的过滤压滤 机、真空过滤使用扶轮过滤器,一个带式压滤机还是一套公寓过滤器,该过滤导致“硅饼”获得 了。The silica cake obtained is then generally subjected to a washing stage, generally washing with water, preferably with a sufficiently long duration, so as to reduce its content of salts, and it is subsequently subjected in stage (f) to drying, in particular by a suitable atomization, for example using a rotary, nozzle, liquid pressure or two-fluid atomizer.硅蛋糕的获取是那么普遍受到一洗 阶段,一般用水,最好有一个足够长的时间,从而减少其内容的盐,及事后于阶段(f)干燥、尤其是 通过合适的雾化,比如用你的扶轮、喷嘴雾化、液体压力或摘要本文采用双流体喷雾器。 In this context, the silica cake is generally disintegrated beforehand, so as to form a silica slurry with a viscosity sufficiently low to provide for the pumping thereof to the atomizer.在此背景下, 硅蛋糕通常解体前,浆,形成了硅和提供充分低粘度的抽止喷雾器。 According to the invention, this slurry exhibits a loss on ignition at 1000.degree.依本发明,该浆展 品损失点火在1000.degree。C. of greater than 82% by weight, preferably of at least 84% by weight, more particularly of 84 to 88% by weight.更大的2001年之重量,特别是对至少84%的重 量,终年84岁,尤其是88%重量。 If appropriate, the disintegrating operation can, for example, be carried out in a known way by subjecting the cake to a mechanical action and optionally to a chemical action (addition of an acid or of an aluminum-based compound).如果恰当,分解操作能,例如,进行一个已知的方式,使蛋糕, 并选择机械作用的一种化学作用(加酸或aluminum-based复合)。 Generally, the slurry of low viscosity resulting from such a disintegration operation is provided in the form of an aqueous silica dispersion which can be directly pumped to an atomizer for stage (f).一般来说,浆产生低粘度的操作提供这样一个瓦解的形式硅水分散可直接通往一个雾化喷嘴 舞台(f)。 The dried silicas obtained in conclusion of stage (f) can optionally be subjected to a stage of agglomeration, in particular by direct compression, by wet granulation (that is to say, with use of a binder, such as water), by extrusion and, preferably, by dry compacting.重点干中获得结论舞台(f) 可以随意地受到良好的阶段,尤其是通过直接压缩,以湿法造粒(也就是说,采用粘结剂,比如 水),以挤压,最好是用干紧密。When the latter technique is employed, it can prove to be advantageous, before carrying out the compacting, to deaerate (operation also referred to as predensifying or degassing) the pulverulent products so as to remove the air included in the latter and to provide more uniform compacting.当后者技术被录用,它不能证明是有利,实施前,压 deaerate(运作也称predensifying或脱气)pulverulent产品,拆卸空包括在后者,并提供更均匀的 紧密。On conclusion of the agglomeration stage, the products can be graded to a desired size, for example by sieving.在结束聚集阶段,产品可分级为我们需要的大小,例如筛。The compacted precipitated silica capable of being obtained is then advantageously provided in the form of granules.压匀后能够获得了沉淀法白炭黑然后推进表格内提供的颗粒。If appropriate, these granules can be provided in the most diverse shapes.如果适宜的话,这些颗粒可以提供在我国多 元文化最丰富多彩形状。The shapes which may be especially mentioned by way of example are spherical, cylindrical, parallelepipedal, tablet, flake, pellet and extrudate of circular or polylobar section.我不喜欢它的形状,尤其可以提到通过举例的方法是球形,长圆柱形,parallelepipedal、 片剂、片状、颗粒及”圆形或polylobar的部分。The mean dimensions of these granules are preferably between 2 and 20 mm.平均维度的这些颗粒最好是2 - 20毫米。 The silica obtained on conclusion of stage (f) and then optionally agglomerated preferably exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm.硅得到的结 论舞台(f),然后展示了一种带有可优先平均粒径偏小或中值粒径之间的30 .mu.m和20毫米。 The silica obtained on conclusion of stage (f) and then optionally agglomerated can subsequently be micronized or, preferably, milled.硅得到的结论舞台(f),然后随之能随意地缩小了带有或,最 好是研磨。 The silica then obtained preferably exhibits a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, especially between 8 and 13 .mu.m.可获得的展示了一种硅优先平均粒径偏小或平均粒径小于 30 .mu.m,特别是对不到20 .mu.m,尤其是在5和15 .mu.m,尤其是长达8 - 13 .mu.m。 Micronizing can be carried out with a micronizer, such as an air jet mill.Micronizing都可以进行 与micronizer,如空气气流磨。 Milling can be carried out in particular using a mechanical mill, for example of the ACM, Forplex, type, in particular a classifier hammer mill.铣削都可以完成特定的用机械工厂,例如 ACM,Forplex、类型、特别是分类器锤厂。 The precipitated silicas according to the present invention exhibit a very good aptitude for dispersing.根据沉淀的重点本发明有很好的天赋消散。They are particularly suitable, advantageously when they exhibit a mean particle size or a median particle diameter of less than 30 .mu.m, preferably of less than 20 .mu.m, in particular of between 5 and 15 .mu.m, for example between 8 and 13 .mu.m (silicas according to the first alternative form of the invention), for use as reinforcing filler in matrices based on elastomer(s), in particular clear or semi-clear elastomer(s), for shoe soles, as reinforcing filler in matrices based on silicone(s), in particular high temperature or room temperature vulcanizable silicone elastomer matrices, on which they confer good rheology properties, while providing them with highly satisfactory mechanical properties.他们尤 其适用的,正好当他们有平均粒径偏小或中值粒径小于30 .mu.m,特别是对不到20 .mu.m,尤 其是在5和15 .mu.m,例如长达8 - 13 .mu.m(重点根据第一种形式的这项发明),作为基础上加 强填料矩阵弹性体(s),尤其是透明或semi-clear弹性体(s),鞋大底,做补强填料矩阵基于硅(s), 尤其是高温或常温vulcanizable硅弹性体矩阵,授予良好的流变学性质,而提供十分满意的力 学性能。 The silicas according to the invention have a particular advantageous application in the reinforcing of matrices based on elastomers, in particular clear or semi-clear elastomers, intended for the manufacture of shoe soles; these dispersible silicas make it possible for strong reinforcing of the transparent or translucent matrices used for the preparation of components made of transparent or translucent rubber which are constituents of shoe soles.依本发明的重点有一种特殊的有利的应 用基础上加强矩阵的弹性体,尤其是透明或semi-clear弹性体,用于制造;这些分散底鞋重点加 强,这使得强大的透明或半透明的矩阵用于制备部件都是由透明或半透明的橡胶的鞋的成分 上鞋底。Advantageously, they make it possible to obtain reinforced matrices having very good transparency.推进,他们就有可能获得钢筋矩阵具有很好的透明性。 The amount of silica according to the invention which can be used in this type of matrix is generally between 10 and 50%, in particular between 20 and 40%, with respect to the weight of the elastomer(s).硅的数量依本发明用于这种类型的矩阵一般在10到50%,尤其是在20 - 40%, 对弹性体的重量(s)。 The silicas according to the invention have an equally advantageous application in the reinforcing of high temperature vulcanizable pasty or elastomeric organosilicon compositions (matrices) (HTV silicones, for example) or room temperature vulcanizable pasty or elastomeric organosilicon compositions (matrices) intended in particular for an insulation role, in particular the coating of electric cables.依本发明的重点有一个同样有利的应用于加固的高温vulcanizable馅饼或弹性 的有机成分(矩阵)(硅树脂,例如)方面或常温vulcanizable馅饼或弹性的有机成分(矩阵)目的, 一个特别的角色,特别是绝缘电线的涂料。Said silicone-based matrices, in particular those intended for an insulation role, can be formed by extrusion, before being crosslinked.说,特别是那 些silicone-based矩阵用于一个绝缘作用,可以形成在受到挤压交联剂。The low value for water uptake of the silicas of the invention makes it possible to avoid or to limit the formation of bubbles, in particular during the extrusion.低价值的水分吸收的重点有可能避免的发明使或限制泡沫的 形成,特别是在挤压板。These silica-based matrices can also be formed by molding.这些硅基矩 阵也可以所形成的成型工艺。The silicas according to the invention advantageously confer, on the silicone matrices, very good electrical and mechanical properties, in particular with regard to tear strength or ultimate strength.依本发明的重点,正好与硅矩阵,非常良好的电气和机械性能, 特别是关于抗撕裂强度或终极力量。 The nature of the vulcanizable organopolysiloxane or organopolysiloxanes present in this type of composition and that of the vulcanizing agents and other additives optionally present, as well as the vulcanizing conditions, are well known to a person skilled in the art; they are disclosed in particular in application WO 03/055801.vulcanizable的性质organopolysiloxane或 organopolysiloxanes出现在这种类型的组成和硫化剂和其它添加剂选择性地存在,以及硫化 条件,是众所周知的人;他们技术领域的应用,特别是,揭示03/055801占用了我们的时间)。 The amount of silica according to the invention which can be employed for the reinforcing of said matrices based on silicones can range from 3 to 20% when silicone pastes are concerned or from 5 to 50%, preferably from 10 to 40%, when a composition of elastomeric nature is concerned.硅的 数量依本发明可以用来加强基础上的“矩阵硅树脂的范围可以从3到20%当硅贴有关或从5 到50%,最好是由原来的10天增加到40%,当构成的弹性性质有关。 A possible application of the silicas according to the invention lies in their use as carrier for liquids, in particular due to their good absorption capacity and a highly satisfactory flowability.一 个可能的应用依本发明重点在于他们使用为载体,液体,特别是那些由于其良好的吸收能力, 有十分满意的性能。 Mention may be made, as liquids, of organic liquids, such as organic acids, surface-active agents, for example of anionic or nonionic type, organic additives for rubber/polymers, or pesticides.提到 可以,就像液体、有机液体,如有机酸、表面活性剂,例如与阴离子或非类型、有机添加剂橡胶 /聚合物、或农药。 Preferably, use is made here, as liquids, in particular of liquid additives, such as flavorings, colorants, liquid food supplements (in particular for the feeding of animals (for example vitamin E, vitamin E acetate or choline hydrochloride)) or preservatives, preferably carboxylic acids (propionic acid, for example).如果有可能的话,使用了这里,像液体,尤其是液体添加剂,如味、色 浆、液体食品添加剂(特别是为喂养动物(例如维生素E,维生素E醋酸盐酸胆碱或)、防腐剂, 最好羧基酸(丙酸,例如)。 The conditioned compositions comprising at least one liquid absorbed on a carrier formed by a silica according to the invention preferably exhibit a liquid content of at least 50% by weight, in particular of between 50 and 75% by weight, for example between 50 and 65% by weight.生成分 包括至少一个液体了白炭黑是由一承运人依本发明有液体内容有至少50%的重量,尤其是以 重量介于50 ~ 75%,例如,50至65%重量。 Furthermore, the silicas of the invention can be employed as filler and/or carrier and/or excipient in various compositions, such as food, cosmetic or pharmaceutical compositions or compositions for the manufacture of paints or paper.此外,重点可以利用的这项发明的填料和/或载体和/或赋 形剂在不同的作品,例如食品、化妆品或药物成分或成分用于制造的油漆或纸。 Mention may also be made of the use, for example in an amount of the order of 60% by weight, of the silica of the invention as carrier for solvent and/or for oil in compositions based on polymers intended for the preparation of separating porous membranes for batteries (battery separator); the solvent and/or the oil carried, once extracted after extrusion/calendaring, give rise to a network of pores.也可以用提及的使用、如在一定数量的订单60%的按重量硅的发明为载体,溶剂和/或对 石油的成分基于聚合物用于制备微孔膜分离技术,提供为电池(电池分离器);溶剂和/或油随身 携带,曾榨取挤压后,引起芳/网络的毛孔。 The silica according to the invention, advantageously when it exhibits a mean particle size or a median particle diameter of between 30 .mu.m and 20 mm (silica according to the second alternative form of the invention), can be incorporated in dentifrice compositions during the preparation of said compositions, which can be provided in the paste or gel form, and can thus make it possible to thicken these compositions or to provide them with the texture.硅的依本发明 时,皆呈现出平均粒径偏小或中值粒径之间的.mu.m和20 30毫米(硅根据第二种形式的这项 发明),可以纳入的牙膏成分制备过程中,可说成分提供粘贴或凝胶形式,人们就能使得它有可 能要想使这些成分或为他们提供纹理。 According to the invention, said silica can be used as thickening or texturing agent in a proportion of 0.1 to 20%, preferably of 0.5 to 15%, very particularly of 1 to 10%, by weight of the dentifrice composition.依本发明硅说,可以用作增厚或材质代理0.1到20%的比例,特别是对0.5 ~ 15%, 非常特别为1至10%,的重量牙膏的作文。 Said dentifrice composition can additionally comprise other normal ingredients, in particular water-insoluble inorganic abrasive agents, optionally other thickening agents, humectants, and the like.说的牙膏成分可以另外包括其他普通成分,特别是非水溶性无机磨料剂、选择性地其他增 稠剂、湿润的,等等。 Mention may in particular be made, as abrasive agents, of abrasive silicas, calcium carbonate, hydrated alumina, bentonite, aluminum silicate, zirconium silicate or sodium, potassium, calcium and magnesium metaphosphates and phosphates.可能特别提到,为重点的代理人,磨料磨具、碳 酸钙、水合氧化铝、膨润土、铝硅酸盐、锆硅酸盐或钠、钾、钙、镁metaphosphates和磷酸 盐。The total amount of abrasive powder(s) can constitute of the order of 5 to 50% of the weight of the dental composition.磨料总额粉(s)也可以构成的次序5到50%的重量的牙科组成。 Mention may be made, among the other thickening agents, of xanthan gum, guar gum, carrageenans, cellulose derivatives, alginates, in an amount which can range up to 5% of the weight of said composition, and the like.提到可以在其他增稠剂、黄原胶,瓜尔胶,carrageenans、 纤维素衍生物、alginates,所涉及的范围可以大数量的5%说的重量组成,等等。 Mention may be made, among the humectant agents, for example, of glycerol, sorbitol, polyethylene glycols, polypropylene glycols or xylitol, in an amount of the order of 2 to 85%, preferably of the order of 3 to 55%, of the weight of dentifrice composition, expressed on a dry basis.提到可以,在humectant代理,举例来说,甘油、山梨醇、聚乙烯、聚丙烯油精油精或木糖 醇、订单数量2 - 85%,最好是为3到55%,重量的牙膏组成,表达了在一个乾的基础。 In addition, these compositions can comprise in particular surface-active agents, detergent agents, colorants, antibacterials, fluorinated derivatives, opacifiers, flavorings, sweeteners, agents for combating tartar or plaque, bleaching agents, sodium bicarbonate, antiseptics, enzymes or natural extracts (camomile, thyme, and the like).此外,这些成分包括特别的表面活性剂、洗涤剂剂、色 浆、抗菌药物、氟化衍生物、opacifiers、调味剂、甜料,代理人为对抗鞑靼或斑块,漂白媒介、 碳酸氢钠抗菌剂、酶制剂或天然精华(洋甘菊,百里香,以及类似的等等。 The following examples illustrate the invention without, however, limiting the scope thereof.下面 的例子描述该发明没有,然而,限制其范围。 EXAMPLES 1-3例1 - 3 Model Opaque Toothpaste模型不透明的牙膏 TABLE-US-00001 sorbitol (Neosorb 70/70 (Roquette Freres)) 45 polyethylene glycol PEG 1500 5 sodium saccharinate 0.2 sodium fluoride 0.08 sodium monofluorophosphate 0.72 water 24.2 abrasive silica (Tixosil 63, sold by Rhodia) 10 silica of the invention 7 titanium dioxide 1 spearmint flavoring 1 foaming agent (30% in water): 5 Texapon Z 95 P (Cognis)TABLE-US-00001 70/70(Roquette山梨醇(Neosorb)Freres 45聚乙二醇盯住美元的汇 率机制1500 5钠saccharinate 0.2氟化钠0.08钠monofluorophosphate 0.72水24.2磨料硅 (Tixosil 63岁,卖出)10 Rhodia硅发明7二氧化钛1薄荷香味1发泡剂(30%在水里):5 Texapon Z 95 P(科宁公司) Measurement of the Viscosity of a Dentifrice Formulation测量的粘度牙膏的制定 The viscosity is determined on a tube of paste with a diameter of 25 mm at predetermined periods at 37.degree.摘要黏度是决定了管贴直径25毫米,以预定的时间在37.degree。C. after preparation of the paste.后之准备酱。 The measurement equipment used is a Brookfield RVT viscometer equipped with a Helipath device.测量设备使用的是布鲁克费尔德RVT粘度计配备了Helipath装置。The TE spindle is used at 5 rpm (revolutions per minute).忒主轴用于5转(转每分钟)。The measurement is carried out in a downward direction after 90 seconds.测量进行了后的向下的90秒。 Example 1例如1 14 000 g of water and 450 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46.14万克水和450克一个236总帐(SiO.sub.2 等价)水水玻璃溶液中引入核反应堆配备一个系统用于调节温度和pH和系统与3-bladed搅 拌桨,SiO.sub.2 / Na.sub.2O率的体重(Rw)的水玻璃使用被346。 After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 95.degree.搅拌开始后(250转每分钟)的,容器跟从而形成了95.degree,加热至。C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute).c和pH值被带到7.5,超过11分钟,乘再加一个80总帐水硫酸解 决方案(平均流量61 g /分钟)。 Once the pH of 7.5 was reached, 3045 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 35 grams per minute (duration of addition: 87 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium.一旦pH 7.5号,3045达成交易的总帐(SiO.sub.2等价)水水玻璃溶液(Rw = 346)以一种 恒定的掌柜还35克流量为每分钟另:87分钟的时间),而保持的酸碱度介质价平到7.5(在0.1 pH单位)的媒介之外,每小时80总帐水硫酸解决方案与流量控制测量了按照变更的酸碱度介 质。Taking stock, 3383 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 40 grams of sulfuric acid solution added per minute.以股 票,3383克硫酸解决添加到中,与平均流量硫酸40克解决每分钟增加。 After the period of addition of 87 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.6.期满后加87分钟的硅酸 盐增加,而酸和补充一直持续到的酸碱度有稳定在化学反应中反应物3.6。Maturing was carried out by leaving the solution to stir for 5 minutes.进行了成熟的解决办法离开搅拌约5分 钟。 The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 80.5%, was disintegrated mechanically at a pH of 5.5 and was then dried by rotary atomization.泥浆进行过滤,并最终获得洗在平坦的过滤,然后蛋糕 其损失点火的解体是80.5%,在未来几年内,机械酸碱度,然后被干燥扶轮雾化。 The physicochemical characteristics of the unmilled dry silica obtained are as follows: pH: 5.9 median particle diameter: 80 .mu.m median diameter after ultrasound: 31.0 .mu.m % greater than 51 .mu.m after ultrasound: 18.6 Na.sub.2SO.sub.4 content: 1.6% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 133 m.sup.2/g BET specific surface: 143 m.sup.2/g DOP oil uptake: 305 ml/100 g loss on ignition at 1000.degree.unmilled的 理化特性的干硅如下:得到5.9将头平均粒径的:80后中值粒径.mu.m超声:北纬31.0 .mu.m % 比51 .mu.m超声:1860 Na.sub.2SO.sub.4后内容:按重量1.6%(相对的总重量在干燥状态) 溴化十六烷三甲基铵的比表面积等:133 m.sup.2 / g BET比面板:143 m.sup.2 / g DOP石油吸 收:305毫升/ 100克损失点火在1000.degree。C.: 6.5% residual water content after 2 hours at 105.degree.c:6.5%残留水份含量在2小时后105.degree。C.: 3.9% water uptake: 5.8% transmission: 80% at a refractive index of 1.460 packing density (PD): 0.27 g/ml viscosity of the model toothpaste after 4 weeks: 250 mPasc:3.9%水分吸收:在:80%传输5.8%折射率的堆积密度 1.460(PD):0.27 g / ml粘滞度的模型牙膏mPas 250 4周 Example 2例子2 The operations described in comparative example 1 are repeated, the dried product being milled so as to obtain a median particle diameter of 10 .mu.m.描述的操作比较例子1是重复的,产品正在 干铣削,才能获得中值粒径10 .mu.m。 The physicochemical characteristics of the milled dry silica obtained are as follows: pH: 5.9 median particle diameter: 10 .mu.m median diameter after ultrasound: 7 .mu.m % greater than 51 .mu.m after ultrasound: 1.0 Na.sub.2SO.sub.4 content: 1.6% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 133 m.sup.2/g BET specific surface: 143 m.sup.2/g DOP oil uptake: 315 ml/100 g loss on ignition at 1000.degree.研磨的理化 特性的干燥,取得了如下:硅中值粒径5.9将头:10 .mu.m中值粒径在超声:7 .mu.m %比 51 .mu.m超声:1.0 Na.sub.2SO.sub.4后内容:按重量1.6%(相对的总重量材料在干燥状态)溴化 十六烷三甲基铵的比表面积等:133 m.sup.2 / g BET比面板:143 m.sup.2 / g DOP石油吸收:315 毫升/ 100克损失点火在1000.degree。C.: 7% residual water content after 2 hours at 105.degree.c:7% 2小时后残余含水量在105.degree。C.: 4.4% water uptake: 5.9% transmission: 80% at a refractive index of 1.460 packing density (PD): 0.1 g/ml viscosity of the model toothpaste after 4 weeks: 325 mPasc:4.4%水分吸收:5.9%传输:80%在折射率的堆积密度 1.460(PD)0.1克/ ml粘滞度的模型牙膏mPas 4周:325 Example 3例3 14 000 g of water and 630 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46.14万克水和630克一个236总帐(SiO.sub.2 等价)水水玻璃溶液中引入核反应堆配备一个系统用于调节温度和pH和系统与3-bladed搅 拌桨,SiO.sub.2 / Na.sub.2O率的体重(Rw)的水玻璃使用被346。 After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 95.degree.搅拌开始后(250转每分钟)的,容器跟从而形成了95.degree,加热至。C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute).c和pH值被带到7.5,超过11分钟,乘再加一个80总帐水硫酸解 决方案(平均流量61 g /分钟)。 Once the pH of 7.5 was reached, 3600 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 48 grams per minute (duration of addition: 75 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium.一旦pH 7.5号,3600达成了交易的总帐(SiO.sub.2等价)水水玻璃溶液(Rw = 346)以一 种恒定的掌柜还48克流量为每分钟另:时间75分钟)同时保持介质酸度的价平到7.5(在0.1 pH单位)的媒介之外,每小时80总帐水硫酸解决方案与流量控制测量了按照变更的酸碱度介 质。Taking stock, 3975 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 53 grams of sulfuric acid solution added per minute.以股 票,3975克硫酸解决添加到中,与平均流速53克硫酸解决每分钟增加。 After the period of addition of 90 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.4.期满后增加90分钟,加入 的硅酸盐停止酸和补充一直持续到反应混合物酸度的稳定在了3.4。Maturing was carried out by leaving the solution to stir for 5 minutes.进行了成熟的解决办法离开搅拌约5分钟。 The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 86%, was disintegrated mechanically at a pH of 5 and was then dried by rotary atomization.泥浆进行过滤,并最终获得洗在平坦的过滤,然后蛋糕其损 失点火的解体86%、是在机械酸碱度的5个,并随即被干扶轮雾化。 The physicochemical characteristics of the unmilled dry silica obtained are as follows: pH: 5.3 median particle diameter: 65 .mu.m median diameter after ultrasound: 22 .mu.m % greater than 51 .mu.m after ultrasound: 3.3 Na.sub.2SO.sub.4 content: 1.0% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 182 m.sup.2/g BET specific surface: 185 m.sup.2/g DOP oil uptake: 340 ml/100 g loss on ignition at 1000.degree.unmilled的 理化特性的干硅,取得了如下:将头5.3平均粒径:65 .mu.m中值粒径后.mu.m超声:22比 51 .mu.m”后3.3 Na.sub.2SO.sub.4内容:超声:按重量1.0%(相对的总重量材料在干燥状态)溴 化十六烷三甲基铵的比表面积等:182 m.sup.2 / g BET比面板:185 m.sup.2 / g DOP石油吸 收:340毫升/ 100克损失点火在1000.degree。C.: 6.5% residual water content after 2 hours at 105.degree.c:6.5%残留水份含量在2小时后105.degree。C.: 3.9% water uptake: 5.7% transmission: 85% at a refractive index of 1.460 packing density (PD): 0.18 g/ml viscosity of the model toothpaste after 4 weeks: 615 mPasc:3.9%水分吸收:5.7%传输:在85%折射率的堆积密度 1.460(PD):0.18 g / ml粘滞度的模型牙膏mPas:146 - 4周 Example 4例句四 14 000 g of water and 450 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution were introduced into a reactor equipped with a system for regulating the temperature and pH and with a system for stirring with a 3-bladed propeller, the SiO.sub.2/Na.sub.2O ratio by weight (Rw) of the sodium silicate used being 3.46.14万克水和450克一个236总帐(SiO.sub.2 等价)水水玻璃溶液中引入核反应堆配备一个系统用于调节温度和pH和系统与3-bladed搅 拌桨,SiO.sub.2 / Na.sub.2O率的体重(Rw)的水玻璃使用被346。 After starting to stir (250 revolutions per minute), the vessel heel thus formed was heated to 98.degree.搅拌开始后(250转每分钟)的,容器跟从而形成了98.degree,加热至。C. and the pH was brought to 7.5, over 11 minutes, by addition of an 80 g/l aqueous sulfuric acid solution (mean flow rate of 61 g per minute).c和pH值被带到7.5,超过11分钟,乘再加一个80总帐水硫酸解 决方案(平均流量61 g /分钟)。 Once the pH of 7.5 was reached, 3150 g of a 236 g/l (as SiO.sub.2 equivalent) aqueous sodium silicate solution (Rw=3.46) were added continuously at a constant flow rate of 35 grams per minute (duration of addition: 90 minutes) while maintaining the pH of the medium at a value equal to 7.5 (to within about 0.1 pH unit) by addition to the medium of an 80 g/l aqueous sulfuric acid solution with a flow rate controlled according to the change measured for the pH of the medium.一旦pH为7.5达成交易的,洗地效率达3510号总帐(SiO.sub.2等价)水水玻璃溶液(Rw = 346)以一种恒定的掌柜还35克流量为每分钟另:90分钟的时间),而保持的酸碱度介质价平 到7.5(在0.1 pH单位)的媒介之外,每小时80总帐水硫酸解决方案与流量控制测量了按照变 更的酸碱度介质。Taking stock, 3510 g of the sulfuric acid solution were added to the medium, which corresponds to a mean flow rate of 39 grams of sulfuric acid solution added per minute.以 股票,法兰硫酸克被添加到溶液中,与平均流量的39克硫酸解决每分钟增加。 After the period of addition of 90 minutes, the addition of silicate was halted and addition of acid was continued until the pH of the reaction mixture had stabilized at 3.4.期满后增加90分钟,加入 的硅酸盐停止酸和补充一直持续到反应混合物酸度的稳定在了3.4。Maturing was carried out by leaving the solution to stir for 5 minutes.进行了成熟的解决办法离开搅拌约5分钟。 The slurry obtained was subsequently filtered and washed on a flat filter and then the cake obtained, the loss on ignition of which is 86.4%, was disintegrated mechanically at a pH of 4.3 and was then dried by rotary atomization.泥浆进行过滤,并最终获得洗在平坦的过滤,然后蛋糕 其损失点火的,在机械86.4%解体的中国酸碱度,然后被干燥扶轮雾化。 The dried silica was subsequently milled using a classifier hammer mill.硅干铣削随后用分类器 锤厂。 The physicochemical characteristics of the silica in the powder form obtained are as follows: pH: 4.6 mean particle size: 12 .mu.m Na.sub.2SO.sub.4 content: 0.25% by weight (with respect to the total weight of the material in the dry state) CTAB specific surface: 166 m.sup.2/g BET specific surface: 170 m.sup.2/g DOP oil uptake: 365 ml/100 g loss on ignition at 1000.degree.的理化特性 的获得白炭黑在粉状如下:pH:46意味着颗粒Na.sub.2SO.sub.4内容:12 .mu.m 0.25%重量(相 对的总重量材料在干燥状态)溴化十六烷三甲基铵的比表面积等:166 m.sup.2 / g BET比面 板:170 m.sup.2 / g DOP石油吸收:365毫升/ 100克损失点火在1000.degree。C.: 5% residual water content after 2 hours at 105.degree.c:5% 2小时后残余含水量在105.degree。C.: 2.5% ater uptake: 5.8% packing density (PD): 0.08 g/ml亚之吸收:5.8%升值(PD):堆积密度为0.08克/曼 梯?里 * * * * *