1、Designation: D788 16Standard Classification System forPoly(Methyl Methacrylate) (PMMA) Molding and ExtrusionCompounds1This standard is issued under the fixed designation D788; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 The purpose of this classi
3、fication system is to provide amethod of adequately identifying PMMA materials using asystem consistent with that of Classification System D4000.Itfurther provides a means for specifying these materials by theuse of a simple line callout designation.1.2 This classification system covers poly(methyl
4、methacry-late) molding and extrusion compounds. These compounds arepolymers based on methyl methacrylate, and at least 70 % ofthe polymer shall be polymerized from methyl methacrylate.1.3 The properties in this classification system are thoserequired to identify the compositions covered. Other requi
5、re-ments necessary to identify particular characteristics importantto specific applications shall be described by using the suffixesas given in Section 5.1.4 Acrylic molding and extrusion compounds are usedfrequently in applications where extreme clarity and the abilityto retain that clarity and col
6、or under severe weathering andother environmental exposures are of primary significance.While the test specimen properties of this document extend tothe evaluation of nonvirgin materials, the user must takeprecautions to ensure that parts made from these materials meetthe desired end-use requirement
7、s. Accordingly, this specifica-tion allows for the use of those acrylic plastic materials that canbe recycled, reconstituted, and reground provided the follow-ing:1.4.1 The requirements as stated in this specification aremet, and1.4.2 The requirements of the particular end-use applicationare met.1.5
8、 This classification system and subsequent line callout(specification) are not intended for the selection of materials,but only as a means to call out plastic materials to be used forthe manufacture of parts. The selection of these materials is tobe made by personnel with expertise in the plastics f
9、ield inwhich the environment, inherent properties of the materials,performance of the parts, part design, manufacturing process,and economics are considered.NOTE 1This classification system is similar to ISO 8257-1:1987 intitle only. The technical content is significantly different.1.6 The values st
10、ated in SI units are to be regarded asstandard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regu
11、latory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD150 Test Methods for AC Loss Characteristics and Permit-tivity (Dielectric Const
12、ant) of Solid Electrical InsulationD257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1003 Test Method for Haze and Luminous Transmittanceof Transparent PlasticsD1238 Test Method for Melt F
13、low Rates of Thermoplasticsby Extrusion PlastometerD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD3641 Practice for Injection Molding Test Specimens ofThermoplastic Molding and Extrusion MaterialsD3892 Practice for Packaging/Packing of Plastics1This classification system is under the j
14、urisdiction ofASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials.Current edition approved Sept. 1, 2016. Published September 2016. Originallyapproved in 1944. Last previous edition approved in 2014 as D788 14. DOI:10.1520/D078816.2For refe
15、renced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyr
16、ight ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D4000 Classification System for Specifying Plastic Materi-alsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 ISO Standards and Recommenda
17、tions:3ISO 179 PlasticsDetermination of Charpy ImpactPropertiesPart 1: Non-Instrumented Impact TestISO 294 PlasticsInjection Moulding of Test Specimens ofThermoplastic MaterialsPart 1: General Principles, andMoulding of Multipurpose and Bar Test SpecimensISO 306 PlasticsThermoplastic MaterialsDeterm
18、inationof Vicat Softening TemperatureISO 489 PlasticsDetermination of the Refractive Index ofTransparent PlasticsISO 527 PlasticsDetermination of Tensile PropertiesISO 1133 PlasticsDetermination of the Melt Flow Rate ofThermoplasticsISO 3167 PlasticsPreparation and Use of MultipurposeTest SpecimensI
19、SO 8257-1 PlasticsPoly(Methyl Methacrylate) (PMMA)Moulding and Extrusion MaterialsPart 12.3 SAE Standards:4SAE J576 SAE Recommended Practice for Plastic Materialsfor Use in Optical Parts such as Lenses and Reflectors forMotor Vehicle Lighting DevicesSAE J2412 SAE Standard for Accelerated Exposure of
20、Automotive Interior Trim Components Using a ControlledIrradiance Xenon-Arc ApparatusSAE J2527 SAE Performance Based Standard for Acceler-ated Exposure of Automotive Exterior Materials Using aControlled Irradiance Xenon-Arc Apparatus3. Terminology3.1 DefinitionsThe terminology used in this classifica
21、tionsystem is in accordance with Terminologies D883 and D1600.4. Basis of Classification4.1 Poly(methyl methacrylate) molding and extrusion com-pounds are classified into groups in accordance with theircomposition. These groups are subdivided into classes andgrades as shown in Table 3. A complete cl
22、assification mustinclude reference to melt-flow rate, as discussed in 4.2 and5.1.4.4.1.1 To facilitate the incorporation of future or specialmaterials, the “other/unspecified” category (0) for group, class,and grade is given in Table 3.4.1.2 When the grade of the basic material is not shown, oris no
23、t important, the use of “0” grade classification shall beused in this classification system.4.2 The melt-flow rate can vary within a given group, class,and grade and can overlap classes or grades. For this reason,the melt-flow rate shall be specified using Suffix V.4.2.1 Although the values listed i
24、n Suffix V are necessary toinclude the range of properties available in existing materials,users must not infer that every melt-flow rate exists for eachclass or grade.NOTE 2An example of this classification system is as follows:The designation PMMA0112 indicates:PMMA = poly(methyl methacrylate) as
25、found in Terminology D1600,01 = unmodified (group),1 = minimum 77C Vicat, etc. (class) and2 = ultraviolet transmitting (grade).(See Note 4 for a more complete example.)NOTE 3Major industries using these materials now require interna-tionally accepted test methods for product specifications. For this
26、 reason,ISO test methods have been used in Table 3 and elsewhere in thisclassification system where appropriate. Similar ASTM standards havebeen listed in Section 2. Many of these ASTM standards are now or soonwill be equivalent. In future editions, a note in the ASTM standard willindicate the degre
27、e of equivalency with a particular international standard.The corresponding ASTM test method is to be substituted as long as thespecimen size and all other conditions of the test method noted in thisclassification system as applying to the ISO test method are also appliedto the ASTM standard.4.3 Gra
28、de 1 materials are used where special ultraviolettransmission, filtering, or stabilization characteristics are notrequired.4.4 Grade 2 materials are used for those specialized appli-cations in which the greatest amount of transmission of UVlight is required. The transmission properties are given in
29、Table1.4.5 Grade 3 materials (transparent UV stabilized or trans-parent UVabsorbing) are used when either special resistance toslight color change over long exposure times or high-intensityUV radiation is required, or when the material is required tofilter out ultraviolet light. These applications a
30、re varied andrequire specific light transmission or color-stability propertiesto be specified by the user.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from SAE International (SAE), 400 Commonwealth Dr., Warr
31、endale,PA 15096-0001, http:/www.sae.org.TABLE 1 Transmission of Grade 2 Materials at VariousWavelengthsA,BWavelength, nm Transmission, min, %400 86340 85310 70290 50280 26270 12AMeasured with UV spectrophotometer using an integrating sphere and a samplethickness of 3.2 mm.BThese requirements are in
32、addition to the luminous transmittance requirementsgiven in Table 3.TABLE 2 Electrical Properties of Unmodified PMMAPropertyTestMethodRequirementInsulation resistance, min, Mohm D257 1107Dielectric strength min, kV/mmAD149 13.8Dielectric constant at 1 MHz, max D150 4.5Dissipation factor at 1 MHz, ma
33、x D150 0.05AkV/mm 25.4 = V mil.D788 1625. Suffixes5.1 When additional requirements are needed, based on theapplication, that are not covered by the basic cell-tablerequirements, they shall be indicated through the use ofsuffixes. In general, suffixes consist of a suffix letter, whichgives the requir
34、ement needed, a first digit, which gives the testcondition, and a second digit, which gives the specific require-ment.5.1.1 Suffix E = Electrical requirements, as designated bythe following digits:First Digit0 = to be specified by the user.1 = specimen thickness, 3.2 mm, nominal.Second Digit0 = to b
35、e specified by the user.1 = volume resistivity, dielectric constant, and dissipation factormeet property limits as given in Table 2.TABLE 3 PMMA Poly(Methyl Methacrylate) Materials Detail RequirementsNoteThe values listed were developed for natural colors. Colorants or other additives, or both, have
36、 the potential to alterthese properties.Group Description Class DescriptionAGrade DescriptionACharpyImpact,TestMethodISO 179BkJ/m2,minTensileStrength,TestMethodISO 527,DMPa, minLuminousTransmittance,Test MethodD1003,E%, minHaze,TestMethodD1003,E%, maxIndex ofRefraction,TestMethodISO 489ETensileModul
37、us,TestMethodISO 527,CMPa, minVicatSofteningTemperature,Test MethodISO 306,FC, min01 UnmodifiedG1 Formerly 1 General purpose . 58 90 2.5 1.48-1.50 2700 77Grade 5 2 UV transmittingH. 58 90 2.5 1.48-1.50 2700 77(D788 - 84) 3 UV stabilizedI. 58 90 2.5 1.48-1.50 2700 772 Formerly 1 General purpose . 62
38、90 2.5 1.48-1.50 2700 86Grade 6 2 UV transmittingH. 62 90 2.5 1.48-1.50 2700 86(D788 - 84) 3 UV stabilizedI. 62 90 2.5 1.48-1.50 2700 863 Formerly 1 General purpose . 65 90 2.5 1.48-1.50 2700 95Grade 8 2 UV transmittingH. 65 90 2.5 1.48-1.50 2700 95(D788 - 84) 3 UV stabilizedI. 65 90 2.5 1.48-1.50 2
39、700 954 Higher VicatSofteningPoint thanFormerGrade 81 General purpose . 65 90 2.5 1.48-1.50 2700 1042 UV transmittingH. 65 90 2.5 1.48-1.50 2700 1043 UV stabilizedI. 65 90 2.5 1.48-1.50 2700 10402 Impact 1 1 1.2 51 88 4.0 1.48-1.50 2600 95modifiedJ0 Other/unspecified. . . . . . .2 1 2.0 38 88 4.0 1.
40、48-1.50 2500 903 1 4.3 31 88 4.0 1.48-1.50 1700 854 1 3.0 31 88 4.0 1.48-1.50 1700 8503 Heat-ResistancemodifiedK1 1 General purpose . 65 90 2.5 1.48-1.50 2700 1132 UV transmittingH. 65 90 2.5 1.48-1.50 2700 1133 UV stabilizedI. 65 90 2.5 1.48-1.50 2700 1134 Impact modified also tbd 56 88 4.0 1.48-1.
41、50 tbd 1132 1 General purpose . 65 90 2.5 1.48-1.50 2700 1222 UV transmittingH. 65 90 2.5 1.48-1.50 2700 1223 UV stabilizedI. 65 90 2.5 1.48-1.50 2700 1223 1 General purpose . 58 90 2.5 1.48-1.52 2700 1134 1 General purpose . 58 90 2.5 1.48-1.52 2700 12200 Other 0 0 Other/unspecified . . . . . . .AN
42、o descriptions are listed unless needed to describe a special grade or class. All other categories are listed by requirements.BMethod designation shall be ISO 179/1eA. Specimen shall be type 1 (4 by 10 by 80 mm) with a typeAnotch radius of 0.25 mm and shall positioned edgewise for impact.Specimens s
43、hall be conditioned in an oven for 16 hours at a set temperature that is 25C below the Vicat softening temperature.CMethod designation shall be ISO 527-2/1A/1. Specimens shall be type 1A and tested at 1 mm/min. Specimens shall be conditioned in an oven for 16 hours at a settemperature that is 25C be
44、low the Vicat softening temperature.DMethod designation shall be ISO 527-2/1A/5. Specimens shall be type 1A and tested at 5 mm/min. Specimens shall be conditioned in an oven for 16 hours at a settemperature that is 25C below the Vicat softening temperature.ETest specimens are 3.2-mm thick of colorle
45、ss material.FMethod designation shall be ISO 306/B50. Specimens shall be 4 mm thick and 10 mm long by 10 mm wide. Specimens shall be conditioned in an oven for 16 hoursat a set temperature that is 25C below the Vicat softening temperature. After conditioning, they must be placed in a desiccator at 2
46、3 2C immediately after molding forat least 1 hour to prevent water pickup and kept dry until ready for test. Specimens must be tested at a temperature rate of 50C/h with a 50 N load.GUnmodified group materials are polymerized from 70 to 100 % methacrylate monomer and 0 to 30 % acrylic comonomers.HSe
47、e 4.4 for description.ISee 4.5 for description.JImpact-modified materials contain 50 to 95 % unmodified polymer and 5 to 50 % of impact modifier(s), maintaining the requirement that the overall composition of thesematerials is polymers made from monomers, at least 70 % of which are methyl methacryla
48、te.KHeat-resistance modified materials are polymerized from 70 to 95 % methyl methacrylate monomer and 5 to 30 % comonomers.D788 1635.1.2 Suffix H = Heat-stability requirements, as designatedby the following digits:First Digit0 = to be specified by the user.1 = 1000 h at 70 2C.2 = 1000 h at 80 2C.3
49、= 1000 h at 90 2C.Second Digit0 = to be specified by the user.1 = change in tensile strength and impact strength not to exceedlimits as given in Table 4A after aging in an air-circulating ovenat the conditions indicated by the first digit and subsequentconditioning according to Section 12.2 = change in tensile strength, tensile elongation, and impactstrength not to exceed limits as given in Table 4B after agingin an air-circulating oven at the conditions indicated by the firstdigit and subsequent conditioning according to Section 12.5.1.3
