ASTM D6778 – 03

Designation: D 6778 – 03 Standard Classification for Polyoxymethylene (POM, Acetal) Molding and Extrusion Materials1 This standard is issued under the fixed designation D 6778; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. 1. Scope* 1.1 This classification covers polyoxymethylene materials suitable for molding and extrusion. This specification allows for the use of polyoxymethylene plastic materials that are recycled, reconstituted, recycled-regrind, recovered, or repro- cessed, or combination thereof, provided that the requirements as stated in this specification are met. It is the responsibility of the supplier and the buyer of recycled, reconstituted, recycled- regrind, recovered, or reprocessed polyoxymethylene plastic materials, or combination thereof, to ensure compliance. (See Guide D 5033). 1.2 The properties included in this classification are those required to identify the compositions covered. There may be other requirements necessary to identify particular character- istics important to specialized applications. These may be specified by using the suffixes as given in Section 5. 1.3 This classification and subsequent line callout are in- tended to provide a means of calling out plastic materials used in the fabrication of end items or parts. It is not intended for the selection of materials. Material selection should be made by those having expertise in the field of plastics design after careful consideration of the design and the performance required of the part, the environment to which it will be exposed, the fabrication process to be employed, the costs involved, and the inherent properties of the material other than those covered by this classification. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 The following precautionary caveat pertains only to the test method portion, Section 11, of this classification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory require- ments prior to use. NOTE 1—This classification is similar to ISO 9988-1 and 9988-2, although the technical content is significantly different. 2. Referenced Documents 2.1 ASTM Standards: 2 D 618 Practice for Conditioning Plastics for Testing D 883 Terminology Relating to Plastics D 1600 Terminology for Abbreviated Terms Relating to Plastics D 3641 Practice for Injection Molding Test Specimens of Thermoplastic Molding and Extrusion Materials D 3892 Practice for Packaging/Packing of Plastics D 4000 Classification System for Specifying Plastic Mate- rials D 5033 Guide for the Development of ASTM Standards Relating to Recycling and Use of Recycled Plastics E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications 2.2 ISO Standards:3 ISO 75-1 Plastics and Ebonite—Determination of Tempera- ture of Deflection under Load—Part 1: General Test Methods ISO 75-2 Plastics—Determination of Temperature of De- flection under Load—Part 2: Plastics and Ebonite ISO 179-1 Plastics—Determination of Charpy Impact Properties—Part 1: Non-instrumented Impact Test ISO 294-1 Plastics—Injection Moulding Of Test Specimens Of Thermoplastic Materials—Part 1: General Principles, and Moulding of Multipurpose and Bar Test Specimens ISO 527-1 Plastics—Determination of Tensile Properties— Part 1: General Principals ISO 527-2 Plastics—Determination of Tensile Properties— Part 2: Test Conditions for Moulding and Extrusion Plastics ISO 1133 Plastics—Determination of the Melt Mass Flow Rate (MFR) and the Melt Volume-Flow Rate (MVR) of Thermoplastics ISO 11357-3 Plastics—Differential Scanning Calorimetry (DSC)—Part 3: Determination of Temperature and En- thalpy of Melting and Crystallization 1 This classification is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials (Section D20.15.18). Current edition approved November 1, 2003. Published January 2004. Originally approved in 2002. Last previous edition approved in 2002 as D 6778 - 02. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 3 Available from American National Standards Institute, 25 W. 43rd St., 4th Floor, New York, NY 10036. 1 *A Summary of Changes section appears at the end of this standard. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. ISO 1183 Plastics—Methods for Determining the Density and Relative Density of Non-Cellular Plastics ISO 3167 Plastics—Multipurpose Test Specimens ISO 9988-1 Plastics—Polyoxymethylene (POM) Moulding and Extrusion Materials—Part 1: Designation System and Basis for Specifications ISO 9988-2 Plastics—Polyoxymethylene (POM) Moulding and Extrusion Materials—Part 2: Preparation of Test Specimens and Determination of Properties TABLE POM Polyoxymethylene Materials, Detail Requirements (Natural and Black Color Only)A,B,C Group Description Class Description Grade Description Flow Rate ISO 1133,D,E G/10 min Melting Point, ISO 11357-3F °C, min Density, ISO 1183, g/cm3 Tensile Strength, ISO 527,G MPa, min Tensile Modulus, ISO 527H MPa, min Charpy Impact Resistance, ISO 179I/ 1eA, kJ/m2, min Deflection Temperature, ISO 75/ Method AfJ 1.82 MPa, °C, min 01 Homopolymer 1 general purpose and high flow 1 <4 170 1.39 to 1.44 65 2400 7.0 80 2 4 to 10 170 1.39 to 1.44 65 2500 6.0 80 3 8 to 19 170 1.39 to 1.44 65 2700 4.5 80 4 19 to 30 170 1.39 to 1.44 65 2700 4.5 85 5 30 to 55 170 1.39 to 1.44 65 2700 4.0 85 G10 10 % glass 170 1.45 to 1.53 80 3500 3.0 150 G25 25 % glass 170 1.55 to 1.63 125 7000 6.0 160 0 other 3 UV stabilized 1 <8 170 1.39 to 1.44 65 2400 7.0 75 2 8 to 19 170 1.39 to 1.44 65 2700 4.5 75 3 19 to 30 170 1.39 to 1.44 65 2700 4.5 75 4 30 to 55 170 1.39 to 1.44 65 2700 4.5 75 0 other 4 impact modified 1 <4 170 1.31 to 1.37 35 800 50.0 50 2 8 to 17 170 1.36 to 1.42 45 1800 8.0 65 3 170 1.32 to 1.38 35 1100 12.0 55 0 other 0 other 02 Copolymer 1 general purpose and high flow 1 <4 160 1.38 to 1.43 58 2000 4.0 80 2 4 to 7 160 1.38 to 1.43 58 2200 3.5 80 3 7 to 11 160 1.38 to 1.43 58 2200 3.5 80 4 11 to 16 160 1.38 to 1.43 58 2000 3.0 80 5 16 to 35 160 1.38 to 1.43 60 2300 3.0 80 6 35 to 60 160 1.38 to 1.43 60 2500 2.5 80 7 60+ 160 1.38 to 1.43 60 2500 2.0 80 G10 10 % glass 160 1.40 to 1.52 70 4000 3.0 150 G15 15 % glass 160 1.45 to 1.55 80 5500 3.0 150 G20 20 % glass 160 1.50 to 1.60 80 6500 3.0 150 G25 25 % glass 160 1.54 to 1.65 80 7300 3.0 150 GE25 25 % glass beads 160 1.50 to 1.70 36 3000 1.0 80 M30 30 % Mineral 160 1.55 to 1.65 40 3500 2.5 80 0 other 2 UV stabilized 1 <4 160 1.38 to 1.43 56 2000 4.0 80 2 4 to 7 160 1.38 to 1.43 56 2000 3.5 80 3 7 to 11 160 1.38 to 1.43 57 2000 3.5 80 4 11 to 16 160 1.38 to 1.43 57 2000 3.0 80 5 16 to 35 160 1.38 to 1.43 58 2100 3.0 80 6 35 to 60 160 1.38 to 1.43 58 2100 2.5 80 7 60+ 160 1.38 to 1.43 58 2100 2.0 80 0 other 3 impact modified 1 11 to 28 155 1.34 to 1.40 46 1800 4.5 70 2 11 to 28 155 1.30 to 1.38 40 1400 4.5 60 3 4 to 12 155 1.34 to 1.40 44 1500 5.0 70 4 4 to 12 155 1.30 to 1.40 35 1300 5.0 60 0 other 4 high modulus 4 11 to 16 165 1.38 to 1.43 64 2700 4.0 80 0 other 03 Terpolymer 1 high melt strength 1 <2 160 1.38 to 1.43 56 2250 3.5 80 0 other 00 Other 0 other 0 other A No descriptions are listed unless needed to describe a special grade under the class. All other grades are listed by requirements. B Refer to 9.1 under Specimen Preparation for source of test pieces. C Data on 4 mm test specimens may be limited and the minimum values may be changed in a later revision after a statistical database of sufficient size is generated. D Flow rate: 190/2.16 (T/M). EFlow rate, g/10 min (MFR) can be converted to flow rate, cc/10 min (MVR) by the relationship MVR = (MFR/density of the melt at 190°C). F Melting point rate 10°C/min. TM second melting curve. G Crosshead speed shall be 50 mm/min 6 10 % unless the specimen exhibits brittle failure (no yield point) and strain at break of <10 % in which case crosshead speed shall be 5 mm/min 6 25 %. H Crosshead speed shall be 1 mm/min. I Notched specimen tested edgewise (method 1eA). J Deflection temperature shall be determined with the specimen in the flatwise position (Method Af). D 6778 – 03 2 TABLE A Detail Requirements: Filled or Reinforced PolyoxymethyleneA,B Designation Order Number Property 0 1 2 3 4 5 6 7 8 9 1 Tensile strength, ISO 527, min, MPaC unspecified 20 35 50 65 90 110 130 150 specify valueD 2 Tensile modulus, ISO 527, min, MPaE unspecified 1500 2500 3500 4500 5500 6500 7500 8500 specify valueD 3 Charpy impact, ISO 179/1eA, min, kJ/m2 unspecified 1.0 2.0 3.0 4.0 6.0 10.0 20.0 40.0 specify valueD 4 Deflection temperature, ISO 75, Method Af, 1.82 MPa, min, °CF unspecified 50 70 90 110 120 130 140 150 specify valueD 5 To be determined unspecified . . . . . . . . . . . . . . . . . . . . . . . . . . . A It is recognized that detailed test values, particularly Charpy impact, may not predict nor even correlate with the performance of parts molded of these materials. B Refer to 9.1 under Specimen Preparation for source of test specimens. C Crosshead speed shall be 50 mm/min 6 10 % unless the specimen exhibits brittle failure (no yield point) and a strain at break of <10 % in which case crosshead speed shall be 5 mm/min 6 25 %. D If specific value is required, it must appear on the drawing or contract, or both. E Crosshead speed shall be 1 mm/min-(method 1eA). F Deflection temperature shall be determined with the specimen in the flatwise position (Method Af). TABLE B Detail Requirements: Special PolyoxymethyleneA,B Designation Order Number Property 0 1 2 3 4 5 6 7 8 9 1 Tensile strength, ISO 527, min, MPaC unspecified 10 20 30 40 50 60 70 80 specify valueD 2 Tensile modulus, ISO 527 min, MPaE unspecified 200 600 1000 1400 1800 2200 2600 3000 specify valueD 3 Charpy impact, ISO 179/1eA, min, kJ/m2 unspecified 1.0 2.0 3.0 4.0 6.0 10.0 20.0 50.0 specify valueD 4 Deflection temperature, ISO 75, Method Af, 1.82 MPa, min, °CF unspecified 40 55 70 80 90 100 110 120 specify valueD 5 To be determined unspecified . . . . . . . . . . . . . . . . . . . . . . . . . . . A It is recognized that detailed test values, particularly Charpy impact, may not predict nor even correlate with the performance of parts molded of these materials. B Refer to 9.1 under Specimen Preparation for source of test specimens. C Crosshead speed shall be 50 mm/min 6 10 % unless the specimen exhibits brittle failure (no yield point) and a strain at break of <10 % in which case crosshead speed shall be 5 mm/min 6 25 %. D If specific value is required, it must appear on the drawing or contract, or both. E Crosshead speed shall be 1 mm/min (method 1eA). F Deflection temperature shall be determined with the specimen in the flatwise position (Method Af). 3. Terminology 3.1 The terminology used in this classification is in accor- dance with Terminologies D 883 and D 1600. 4. Classification 4.1 Unreinforced polyoxymethylene materials are classified into groups in accordance with their composition. These groups are subdivided into classes and grades, as shown in Table POM. NOTE 2—An example of this classification system is as follows. The designation POM0112 indicates the following: POM = polyoxymethylene (acetal) as found in Terminology D 1600, 01 = homopolymer (group), 1 = general purpose and high flow (class), and 2 = requirements given in Table POM (grade). 4.1.1 To facilitate the incorporation of future or special materials, the “other/unspecified” category (0) for group, class, and grade is shown in Table POM. The basic properties can be obtained from Tables A or B, as they apply (see 4.3). 4.2 Reinforced, filled, lubricated and special versions of the polyoxymethylene materials that are not in Table POM are classified in accordance with Table POM and Tables A or B. Table POM is used to specify the group of polyoxymethylene and Table A or B is used to specify the property requirements after the addition of reinforcement, pigments, fillers, or lubri- cants at the nominal level indicated (see 4.2.1). 4.2.1 Reinforced versions of the basic materials are identi- fied by a single letter that indicates the reinforcement used and two digits that indicate the nominal quantity in percent by weight. Thus, a letter designation G for glass-reinforced and 33 for percent of reinforcement, G33, specifies a filled material with a nominal glass level of 33 %. The reinforcement letter designations and associated tolerance levels are shown as follows: Symbol Material Tolerance C carbon and graphite fiber-reinforced 62 % G glass-reinforced 62 % L lubricants (such as, PTFE, graphite, silicone, and molybdenum disulfide) depends upon material and process to be specified M mineral-reinforced 62 % R combinations of reinforcements or fillers, or both 63 % NOTE 3—This part of the classification system uses the percent of reinforcements or additives, or both, in the callout of the modified basic material. The types and percentages of reinforcements and additives D 6778 – 03 3 should be shown on the supplier’s technical data sheet, unless they are proprietary in nature. If necessary, additional callout of these reinforce- ments and additives can be accomplished by use of the suffix part of the system (see 1.2). 4.2.2 Specific requirements for reinforced, filled, lubricated or special polyoxymethylene materials shall be shown by a six-character designation. The designation will consist of the letter A or B and the five digits comprising the cell numbers for the property requirements in the order as they appear in Tables A or B. 4.2.2.1 Although the values listed are necessary to include the range of properties available in existing materials, users should not infer that every possible combination of the properties exists or can be obtained. 4.2.3 When the grade of the basic material is not known or is not important, the use of “0” grade classification will be used for reinforced materials in this system. NOTE 4—An example of this classification for a reinforced polyoxym- ethylene material is as follows. The designation POM0210G25A65380 indicates the following material requirement: POM = Polyoxymethylene (acetal) as found in Terminology D 1600, 02 = Copolymer (group), 1 = General purpose and high flow (class), 0 = Other (grade), G 25 = Glass-reinforced at 25 % nominal level, A = Table A property requirements, 6 = Tensile strength, 110 MPa, min, 5 = Tensile modulus, 5500 MPa, min, 3 = Charpy impact, 3.0 kJ/m2, min, 8 = Deflection temperature, 150°C, min, and 0 = Unspecified. If no properties are specified, the designation would be POM0210G25A00000. 4.3 Table B has been incorporated into this classification to facilitate the classification of special materials where Table POM or Table A does not reflect the required properties. Table B shall be used in the same manner as Table A. NOTE 5—The mechanical properties of pigmented or colored poly- oxymethylene materials can differ from the mechanical properties of natural and black polyoxymethylene material, depending on the choice of colorants and the concentration. The main property affected is ductility, as illustrated by a reduction in impact strength. If specific properties of pigmented materials are necessary, Table B should be employed to specify property requirements. NOTE 6—An example of this classification system for a special poly- oxymethylene material is as follows. The designation POM0110B44250 indicates: POM = Polyoxymethylene (acetal) as found in Terminol- ogy D 1600, 01 = Homopolymer (group), 1 = General purpose and high flow (class), 0 = Other (grade), B = Table B property requirements, 4 = Tensile strength, 40 MPa, min, 4 = Tensile modulus, 1400 MPa, min, 2 = Charpy impact, 2.0 kJ/m2, min, 5 = Deflection temperature, 90°C, min, and 0 = Unspecified. 5. Suffix Requirements 5.1 When additional requirements are needed that are not covered by the basic requirements or cell-table requirements, they shall be indicated through the use of suffixes. 5.2 A list of suffixes can be found in Classification System D 4000 (Table 3) and may be used for additional requirements as appropriate. Additional suffixes will be added to that standard as test methods and requirements are developed and requested. 6. General Requirements 6.1 Basic requirements from property tables of cell tables are always in effect unless superseded by specific suffix requirements, which always take precedence. 6.2 The plastics composition shall be uniform and shall conform to the requirements specified herein. 7. Detail Requirements 7.1 The materials shall conform to the requirements in Tables POM, A, and B and suffix requirements, as they apply. 7.2 For the purposes of determining conformance, all speci- fied limits for a specification (line callout) based on this classification system are absolute limits, as defined in Practice E 29. 7.3 With the absolute method, an observed value or a calculated value is not rounded, but is to be compared directly with the limiting value. 8. Sampling 8.1 Sampling shall be statistically adequate to satisfy the requirements of 12.4. 8.2 A batch or lot shall be constituted as a unit of manufac- ture as prepared for shipment, and may consist of a blend of two or more “production runs.” 9. Specimen Preparation 9.1 Test pieces for relevant test methods shall be based on the injection molded ISO 3167 Type 1A multipurpose test specimen. The following pieces are to be used for the listed relevant test methods. All test pieces are to be tested as molded and conditioned. Annealing is not allowed. Test Piece Relevant Test Method ISO 3167 Type 1A Bar Tensile strength and modulus by ISO 527 80 6 2 mm 3 10 6 0.2 mm 3 4 6 0.2 mm cut from the center portion of ISO 3167 Type 1A Bar Charpy impact resistance by ISO 179/1eA Deflection temperature by ISO 75/Method Af Specimen approximately 10 3 10 3 4 mm cut from center of ISO 3167 Type 1A Bar Density by ISO 1183 9.2 The test specimens shall be molded by injection mold- ing in accordance with Practice D 3641 and ISO 294-1 and ISO 9988-2. Recommended processing conditions are shown in Table 1. 10. Conditioning 10.1 Test specimens shall be conditioned in the standard laboratory atmosphere for a minimum of 16 h (Condition 16/23/50, Practice D 618) before performing the required tests. D 6778 – 03 4 10.2 Conduct tests in the standard laboratory atmosphere of 23 6 2°C and 50 6 5 % relative humidity in accordance with Practice D 618. 11. Test Methods 11.1 Determine the properties enumerated in this classifica- tion by means of the test methods in 1.1. 11.1.1 The number of tests shall be consistent with the requirements of Section 8 and 12.4. 12. Inspection and Certification 12.1 Inspection and certification of the material supplied with reference to a specification based on this classification system shall be for conformance to the requirements specified herein. 12.2 Lot-acceptance inspection shall be the basis on which acceptance or rejection of the lot is made. The lot-acceptance inspection shall consist of melt flow rate or reinforcement content. 12.3 Periodic check inspection with reference to a specifi- cation based on this classification system shall consis