1、Designation: D3294 09Standard 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.1.2 This specification also establishes requirements formolded basic shapes made from molding and extrusion mate-rials. This specification is for produ
4、cts 300 mm (12 in.) or lessin a dimension parallel to and 12.7 mm (0.5 in.) or greater inthe dimension perpendicular to the direction of the appliedmolding pressure.1.3 The values stated in SI units are to be regarded as thestandard.1.4 The following precautionary caveat pertains only to thetest met
5、hod 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 applicability of regulatory l
6、imita-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 Insulating Materialsa
7、t Commercial Power FrequenciesD618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated
8、 Terms Relating toPlasticsD1708 Test Method for Tensile Properties of Plastics byUse of Microtensile SpecimensD3892 Practice for Packaging/Packing of PlasticsD4591 Test Method for Determining Temperatures andHeats of Transitions of Fluoropolymers by DifferentialScanning CalorimetryE94 Guide for Radi
9、ographic ExaminationIEEE/ASTM SI-10 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 uni
10、formblend of two or more production runs of one size sheet ormolded basic shape.3.2 Abbreviations:Abbreviations are in accordance withTerminology D1600.4. Classification4.1 This specification covers the following four types ofmolded basic sheets and shapes:4.1.1 Type IPremium; normally used for exac
11、ting electri-cal, mechanical, or chemical applications.4.1.2 Type IIGeneral purpose; for electrical, mechanical,and chemical applications not requiring premium material.4.1.3 Type IIIMechanical Grade; for non-critical chemi-cal, electrical, and mechanical applications.4.1.4 Type IVUtility; having no
12、 electrical requirementsand with mechanical properties at a lower level.4.2 Types 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.1This specification is under the jurisdiction of ASTM Committee D20 onPlas
13、tics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials (Section D20.15.12).Current edition approved Nov. 1, 2009. Published December 2009. Originallyapproved in 1974. Last previous edition approved in 2003 as D3294 - 03. DOI:10.1520/D3294-09.2For referenced ASTM stand
14、ards, 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Inter
15、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 Class Bthermal dimensional change not exceeding5.0 %.4.3
16、.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.SpecificationStandard Number : Type : Grade : Class :
17、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 Type, Grade, and Class in the appropriate specifiedpro
18、perties, 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.3Provision for Special Notes is included sothat other information shall be provided when required. Anexample
19、 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 in thisspecification shall be ordered stating the ty
20、pe, 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. Requirements Requirements7.1 The sheet covered by this s
21、pecification 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 when tested by the test methods given in
22、 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 specified in the contract or order.8.2 The to
23、lerance 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, but oftenhave occasional spots. Types II, III, and IV are typically white,but will vary to light gray or light brown. For Types II, III, a
24、ndIV occasional small gray, brown, or black spots shall not beconsidered 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
25、 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
26、outine lot inspection tests shall consist of all the testsspecified in Table 1, Table 2,orTable 3.11.2 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 state
27、d in the test method, single determination 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
28、 Appendix X1 provideadditional information. The data shown are informational onlyand shall not be used for specification purposes.3See the ASTM Form and Style Manual. Available from ASTM InternationalHeadquarters.TABLE 1 Physical and Electrical Requirements for PTFE SheetsATypesTensileStrengthA(min)
29、 psiElonga-tionA(min)PercentDielectricStrengthB(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
30、13.6EPTFE sheet used for tank lining 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 2
31、40 850 2.14 to 2.19III 1500 75 250 2.13 to 2.20D3294 09212. 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 least four h prior to test.12.2 Stand
32、ard 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 important.13. Test Methods13.1 Visual and D
33、imensional 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 ormolded basic shapes shall be inte
34、rpreted 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 strength and elongation in accordance w
35、ith 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 of thin cardboardbetween said hard su
36、rface and sample.13.2.2 Testing shall be at a speed of 50.8 mm (2 in.)/min.13.2.3 Determine elongation 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
37、the micro-specimen as speci-fied in 13.2.1 prepare specimens by turning a 0.8-mm (132-in.)thick-walled 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
38、 the tube. Lathe-turn the tube insuch a manner that the specimen is taken from the center of theoriginal wall thickness. In the case of a rod, remove the outer1.6 mm (116 in.) before finish turning the outer diameter of theTABLE 3 Nominal Thickness and Tolerances for PTFE SheetsThicknessInchToleranc
39、eInchThicknessInchToleranceInchThicknessInchToleranceInch132 +0.01514 +0.030 114 +0.1020.005 0.015 0.051116 +0.01538 +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
40、 1 +0.0870.011 0.043NOTE 1Dimensions in millimetres.FIG. 1 Microtensile DieISOD3294 093tube. 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 thickness, fivemicro-specimens with the stee
41、l 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. Fromsheets 15.9 mm (58 in.) and over in th
42、ickness, 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.) bymachining, tool marks shall be
43、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, theelectrodes shall be 63.5 mm (14
44、 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 electrodes with rounded edges.13.3.3
45、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 detergent)4tothe water in order to redu
46、ce 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 temperaturethroughout.13.5.2 Significance and
47、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 cleaner.5Remove theexcess cleaner an
48、d permit the surface to dry for at least 5 min.13.5.4 Deposit a film of penetrant5on 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
49、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 penetrant. Retained areas ofpenetrant that appear cloudy or hazy indicate porosity. Occa-sional superficial flaws in PTFE sheet or moldings shall not beinterpreted as porosity.13.5.6 Precision and BiasThe precision and bias for thispenetrant-die test will be determined.13.6 Dimensional StabilityDetermine the thermal dimen-sional change o
