1、Designation: D3294 15Standard Specification forPolytetrafluoroethylene (PTFE) Resin Molded Sheet andMolded Basic Shapes1This standard is issued under the fixed designation D3294; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year 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.1. Scope*1.1 This specification establishes requirements and methodsof test for the material, dimensions, and workmanship,
3、 and thephysical and electrical properties of molded sheet in minimumthicknesses of 0.794 mm (132 in.) manufactured from PTFEresin molding materials defined in Specification D4894.1.2 This specification also establishes requirements formolded basic shapes made from molding materials. Thisspecificati
4、on is for products 300 mm (12 in.) or less in adimension parallel to and 12.7 mm (0.5 in.) or greater in thedimension perpendicular to the direction of the applied mold-ing pressure.1.3 The values stated in SI units are to be regarded as thestandard.1.4 The following precautionary caveat pertains on
5、ly to thetest method portion, Section 7, of this specification. Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicabilit
6、y of regulatory limita-tions prior to use. Special attention is called to 13.2, 13.3, 13.6,13.8, and A1.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insu
7、lating Materialsat Commercial Power FrequenciesD374 Test Methods for Thickness of Solid Electrical Insu-lation (Withdrawn 2013)3D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD792 Test Methods for Density and Specific Gravity (Rela-tive Density)
8、 of Plastics by DisplacementD883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsD1708 Test Method for Tensile Properties of Plastics by Useof Microtensile SpecimensD3892 Practice for Packaging/Packing of PlasticsD4591 Test Method for Determining Temperatu
9、res andHeats of Transitions of Fluoropolymers by DifferentialScanning CalorimetryD4894 Specification for Polytetrafluoroethylene (PTFE)Granular Molding and Ram Extrusion MaterialsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE94 Guide for Radiographic ExaminationIEEE/ASTM SI-1
10、0 American National Standard for Use ofthe International System of Units (SI): The Modern MetricSystem3. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Terminology D883unless otherwise specified.3.1.2 lot, none continuous production run or a uniformblend of two or more productio
11、n runs of one size sheet ormolded basic shape.3.2 Abbreviations:3.2.1 Abbreviations are in accordance with TerminologyD1600.4. Classification4.1 This specification covers the following four types ofmolded basic sheets and shapes:4.1.1 Type IPremium; normally used for exactingelectrical, mechanical,
12、or chemical applications.1This specification is under the jurisdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials (Section D20.15.12).Current edition approved Sept. 1, 2015. Published September 2015. Originallyapproved in 1974.
13、Last previous edition approved in 2009 as D3294 - 09. DOI:10.1520/D3294-15.2For referenced 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
14、 ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.2 Type IIGeneral pu
15、rpose; for electrical, mechanical,and chemical applications not requiring premium material.4.1.3 Type IIIMechanical Grade; for non-criticalchemical, electrical, and mechanical applications.4.1.4 Type IVUtility; having no electrical requirementsand with mechanical properties at a lower level.4.2 Type
16、s I, II, and III shall be subdivided into two gradesas follows:4.2.1 Grade 1made only from virgin resin.4.2.2 Grade 2made using reprocessed resin.4.3 The grades shall be further subdivided into three classesas follows:4.3.1 Class Aresistant to thermal dimensional change notexceeding 0.5 %.4.3.2 Clas
17、s Bthermal dimensional change not exceeding5.0 %.4.3.3 Class Cno requirement for thermal dimensionalchange.4.4 A one-line system shall be used to specify materialscovered by this specification. The system uses predefined cellsto refer to specific aspects of this specification, as illustratedbelow.Sp
18、ecificationStandard Number : Type : Grade : Class : SpecialBlock : : : : Notes:Example: Specification D3294 03, I I AFor this example, the line callout would be SpecificationD3294 03, 11A and would specify premium virgin form ofpolytetrafluoroethylene that has all of the properties listed forthat Ty
19、pe, Grade, and Class in the appropriate specifiedproperties, tables, or both, in the specification identified. Acomma is used as the separator between the standard Numberand the Type. Separators are not needed between the Type,Grade, and Class.4Provision for Special Notes is included sothat other in
20、formation shall be provided when required. Anexample would be in Specification D3295 where dimensionsand tolerances are specified for each AWG size within Typeand Class. When Special Notes are used, they shall be precededby a comma.5. Ordering Information5.1 The molded sheet or basic shapes covered
21、in thisspecification shall be ordered stating the type, grade, and classand that they meet the requirements of this specification.6. Materials6.1 The sheet or molded basic shape from Types I, II, III, orIV shall be made from unpigmented PTFE as free of foreignmatter as commercially practical.7. Requ
22、irements7.1 The sheet covered by this specification shall meet thephysical and electrical requirements specified in Table 1 whentested by the methods given in Section 13.7.2 The molded basic shapes covered by this specificationshall meet the physical and electrical requirements specified inTable 2 w
23、hen tested by the test methods given in Section 13.7.2.1 Melting Pointthe melting point of all types of sheetand molded basic shapes shall be 327 6 10C when tested inaccordance with paragraph 13.8.8. Dimensions8.1 The size, shape, dimensional tolerances, and dimen-sional stability shall be as specif
24、ied in the contract or order.8.2 The tolerance on length and width shall be plus 6.3 mm(14 in.), minus 0 mm (0 in.).9. Workmanship, Finish, and Appearance9.1 ColorType I shall be white to translucent. Types II,III, and IV are typically white, but vary to off white or lightgray. For Types II, III, an
25、d IV occasional small gray, brown, orblack spots shall not be considered as cause for rejection.9.2 FinishThe material shall be as free as is commerciallypractical from surface blisters, wrinkles, cracks and othersurface defects that might affect its serviceability. It shall alsobe commercially free
26、 of macroscopic voids, cracks, and foreigninclusions.9.3 Internal DefectsThe moldings shall be as free as iscommercially practical of microscopic voids, cracks, andforeign inclusions.10. Sampling10.1 Sampling shall be statistically adequate to satisfy therequirements of 15.111. Number of Tests11.1 R
27、outine lot inspection tests shall consist of all the testsspecified in Table 1, Table 2,orTable 3.4See the ASTM Form and Style Manual. Available from ASTM InternationalHeadquarters.TABLE 1 Physical and Electrical Requirements for PTFE SheetsATypesTensileStrengthA(min) psiElonga-tionA(min)PercentDiel
28、ectricStrengthB(min) VoltsPer MillSpecificCGravityPorosityDI 4500 300 600 2.15 to 2.18EZero penetrationII 3000 225 500 2.14 to 2.19 Not requiredIII 2000 150 300 2.13 to 2.19 Not requiredIV 1300 75 Not required 2.13 to 2.20 Not requiredASee 13.2.BSee 13.3CSee 13.4DSee 13.6EPTFE sheet used for tank li
29、ning shall be Type I but shall have a specific gravityof 2.19 to 2.22.TABLE 2 Physical and Electrical Requirements for Basic ShapesTypesTensile Strengthpsi (min)Elongation %(min)DielectricStrength Voltsper mil (min)Specific GravityI 4800 325 1200 2.14 to 2.18II 3200 240 850 2.14 to 2.19III 1500 75 2
30、50 2.13 to 2.20IV 1500 75 Not required 2.13 to 2.20D3294 15211.2 The tests listed in Table 1 and Table 2, as they apply,are sufficient to establish conformity of the PTFE sheet or basicshapes to this specification. When the number of test speci-mens is not stated in the test method, single determina
31、tion shallbe made. If more than single determinations and separateportions of the same sample are made, the results shall beaveraged. The single or average result shall conform to therequirements prescribed in this specification.11.3 The properties listed in the Appendix X1 provideadditional informa
32、tion. The data shown are informational onlyand shall not be used for specification purposes.12. Test Conditions12.1 Conditioning of SpecimensUnless otherwise speci-fied in this specification, the test specimens shall be condi-tioned in accordance with Procedure A of Practice D618 for aperiod of at l
33、east four h prior to test.12.2 Standard TemperatureUnless otherwise specified,the tests shall be conducted at the standard laboratory tempera-ture of 23C 6 2C (73.4F 6 3.6F). Since the sheet ormolded basic shape does not absorb water, the maintenance ofconstant humidity during testing is not importa
34、nt.13. Test Methods13.1 Visual and Dimensional InspectionEach of thesample PTFE sheets or molded basic shapes selected inaccordance with Section 10 shall be visually and dimensionallyinspected to verify their compliance with the requirements ofthe standard. Occasional superficial flaws in PTFE sheet
35、 ormolded basic shapes shall be interpreted as neither affecting theporosity nor soundness of the molding. Such flaws arescratches, edge cracks, and the adherence of resin flakes. Suchindications shall not be cause for rejection.13.2 Tensile Strength and ElongationDetermine the ulti-mate tensile str
36、ength and elongation in accordance with TestMethod D638 except as follows:13.2.1 Cut five micro-specimens with the steel rule die andthe dimensions shown in Fig. 1 using a hydraulic or mechani-cal press. When cutting a specimen, back it by a hard surfaceboard such as masonite or equal with a piece o
37、f thin cardboardbetween said hard surface and sample.13.2.2 Testing shall be at a speed of 50.8 mm (2 in.)/min.TABLE 3 Nominal Thickness and Tolerances for PTFE SheetsThicknessInchToleranceInchThicknessInchToleranceInchThicknessInchToleranceInch132 +0.01514 +0.030 114 +0.1020.005 0.015 0.051116 +0.0
38、1538 +0.038 112 +0.1180.005 0.019 0.059332 +0.02012 +0.046 134 +0.1340.005 0.022 0.06718 +0.01658 +0.054 2 +0.1500.008 0.027 0.075532 +0.01834 +0.070 Over 2 +10 %0.009 0.035 10 %316 +0.022 1 +0.0870.011 0.043NOTE 1Dimensions in millimetres.FIG. 1 Microtensile DieISOD3294 15313.2.3 Determine elongati
39、on by using an initial jaw separa-tion of 22.2 mm (0.875 in.) and expressed as a percentage ofthe initial jaw separation.13.2.4 Alternative SpecimensWhen the shape of thesample does not permit making the micro-specimen as speci-fied in 13.2.1 prepare specimens by turning a 0.8-mm (132-in.)thick-wall
40、ed tube from the shape, and cutting dumbbells fromthe tube wall in a direction perpendicular to the appliedmolding pressure, that is, with the long axis of the dumbbellparallel to the circumference of the tube. Lathe-turn the tube insuch a manner that the specimen is taken from the center of theorig
41、inal wall thickness. In the case of a rod, remove the outer1.6 mm (116 in.) before finish turning the outer diameter of thetube. Turn both inside and outside surfaces with a fine lathefeed and sharp tools to permit the smoothest possible finish.13.2.5 Cut sheets 1.6 mm (116 in.) or under in thicknes
42、s, fivemicro-specimens with the steel rule die and the dimensionsshown in Fig. 1 using a hydraulic or mechanical press.Machine sheets thicker than 1.6 mm (116 in.) and thinner than15.9 mm (58 in.) to a thickness of 1.6 6 0.25 mm (116 6 0.010in.) and five specimens from these reduced portions. Fromsh
43、eets 15.9 mm (58 in.) and over in thickness, a slice somewhatthicker than 1.6 mm (116 in.) shall be cut from one edge but notless than 12.7 mm (12 in.) distance from that edge and bothfaces machined to a thickness of 1.6 6 0.25 mm (116 6 0.010in.). In all cases of specimens reduced to 1.6 mm (116 in
44、.) bymachining, tool marks shall be removed by light sanding in alongitudinal direction.13.3 Dielectric StrengthDetermine the dielectric strengthin accordance with Test Method D149 using five specimensand the short-time test under oil, except as follows:13.3.1 When 25.4 mm (1 in.) specimens are used
45、, theelectrodes shall be 63.5 mm (14 in.) in diameter, with edgesrounded to a 0.8 mm (132 in.) radius.13.3.2 If the size of the molding does not permit 25.4 mm (1in.) wide specimens, 12.7 mm (12-in.) discs or strips 0.5 6 0.05mm (0.020 6 0.002 in.) thick shall be used with 1.6-mm(116-in.) diameter e
46、lectrodes with rounded edges.13.3.3 The specimen must extend sufficiently far beyond theelectrode edge so that a flash-over does not occur.13.4 Specific GravityDetermine the specific gravity ontwo specimens in accordance with Method A of Test MethodsD792. Add two drops of a wetting agent (liquid det
47、ergent)5tothe water in order to reduce the surface tension and insurecomplete wetting of the sample.13.5 PorosityDetermine the porosity of Type I sheet ormolded shape by the penetrant test.13.5.1 ScopeThe test for porosity is to determine that themolding has received adequate pressure and temperatur
48、ethroughout.13.5.2 Significance and UseThe significance of this testfor porosity is to indicate if the molding has been properlymanufactured.13.5.3 Use one full size sheet or molding for the porositytest. Degrease the entire surface on the molding with foldedpaper wiping tissues wet with a suitable
49、cleaner.6Remove theexcess cleaner and permit the surface to dry for at least 5 min.13.5.4 Deposit a film of penetrant6on the entire surface ofthe molding and allow to stand for 5 min. If the penetrantappears to dry prematurely, rewet the surface with penetrantand allow to dry for 1 min longer. Then, remove the penetrantby wiping with a tissue and scrub the entire surface thoroughlywith tissues wet with cleaner.13.5.5 When dry, inspect entire surface for indication ofdiscoloration caused by the penet
