1、Designation: D 3294 03Standard Specification forPolytetrafluoroethylene (PTFE) Resin Molded Sheet andMolded Basic Shapes1This standard is issued under the fixed designation D 3294; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 workmansh
3、ip, 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 resin molding and extrusionmaterials. This specification is for
4、products 300 mm 12 in. orless in a dimension parallel to and 12.7 mm 0.5 in. or greaterin the 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 me
5、thod 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
6、limita-tions prior to use. Special attention is called to 13.2, 13.3, 13.6,13.8, and A1.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:D 149 Test Method for Dielectric Breakdown Voltage andDielectric Strength of Solid Electrical Insulating Materialsat
7、Commercial Power Frequencies2D 618 Practice for Conditioning Plastics for Testing3D 638 Test Method for Tensile Properties of Plastics3D 792 Test Methods for Specific Gravity (Relative Density)and Density of Plastics by Displacement3D 883 Terminology Relating to Plastics3D 1505 Test Method for Densi
8、ty of Plastics by the Density-Gradient Technique3D 1600 Terminology for Abbreviated Terms Relating toPlastics3D 1708 Test Method for Tensile Properties of Plastics byUse of Microtensile Specimens3D 3892 Practice for Packaging/Packing of Plastics4D 4591 Test Method for Determining Temperatures andHea
9、ts of Transitions of Fluoropolymers by DifferentialScanning Calorimetry5D 4894 Specification for Polytetrafluoroethylene (PTFE)Granular Molding and Ram Extrusion Materials5E 94 Guide for Radiographic Testing6IEEE/ASTM SI-10 American National Standard for Use ofthe International System of Units (SI):
10、 The Modern MetricSystem73. Terminology3.1 Definitions:3.1.1 Definitions are in accordance with Terminology D 883unless otherwise specified.3.1.2 lot, none continuous production run or a uniformblend of two or more production runs of one size sheet ormolded basic shape.3.2 Abbreviations:Abbreviation
11、s are in accordance withTerminology D 1600.4. Classification4.1 This specification covers the following four types ofmolded basic sheets and shapes:4.1.1 Type IPremium; normally used for exacting electri-cal, mechanical, or chemical applications.4.1.2 Type IIGeneral purpose; for electrical, mechanic
12、al,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 electrical requirementsand with mechanical properties at a lower level.1This specification is under the juri
13、sdiction of ASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials (Section D20.15.12).Current edition approved April 10, 2003. Published June 2003. Originallyapproved in 1974. Last previous edition approved in 1997 as D 3294 - 97.2Annual Book
14、 of ASTM Standards, Vol 10.02.3Annual Book of ASTM Standards, Vol 08.01.4Annual Book of ASTM Standards, Vol 08.02.5Annual Book of ASTM Standards, Vol 08.03.6Annual Book of ASTM Standards, Vol 03.03.7Available from ASTM International, 100 Barr Harbor Drive, C700, WestConshohocken, PA 19428.1*A Summar
15、y 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.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
16、 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 Class Bthermal dimensional change not exceeding5.0 %.4.3.3 Class Cno requirement for thermal dimensionalchange.4.4 A one-line
17、 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 : SpecialBlock : : : : Notes:Example: Specification D 3294 03, I I AFor
18、 this example, the line callout would be SpecificationD 3294 03, 11A and would specify premium virgin form ofpolytetrafluoroethylene that has all of the properties listed forthat Type, Grade, and Class in the appropriate specifiedproperties, tables, or both, in the specification identified. Acomma i
19、s used as the separator between the standard Numberand the Type. Separators are not needed between the Type,Grade, and Class.8Provision for Special Notes is included sothat other information shall be provided when required. Anexample would be in Specification D 3295 where dimensionsand tolerances ar
20、e 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 type, grade, and classand that they meet the requirements of this sp
21、ecification.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. Requirements7.1 The sheet covered by this specification shall meet thephysical and electrical requirements specified in Ta
22、ble 1 andparagraph 7.1.1 when tested by the methods given in Section13.7.2 The molded basic shapes covered by this specificationshall meet the physical and electrical requirements specified inTable 2 and 7.1.1 when tested by the test methods given inSection 13.7.2.1 Melting Pointthe melting point of
23、 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 tolerance on length and width shall be plus 6.3 mm14
24、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, andIV occasional small gray, brown, or black spots shall
25、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 of macroscopic voids, cracks, and foreigninclusions.9.3
26、 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 Routine lot inspection tests shall consist of all the tes
27、tsspecified in Table 1, Table 2, or Table 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 stated in the test method, single determination shallbe mad
28、e. If more than single determinations and separate8See the ASTM Form and Style Manual. Available from ASTM InternationalHeadquarters.TABLE 1 Physical and Electrical Requirements for PTFE SheetsATypesTensileStrengthA(min) psiElonga-tionA(min)PercentDielectricStrengthB(min) VoltsPer MillSpecificCGravi
29、tyPorosityDI 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 lining shall be Type I but shall have a specific g
30、ravityof 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 75 250 2.13 to 2.20D3294032portions of the same samp
31、le 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 information. The data shown are informational onlyand shall not be used for specification purposes
32、.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 D 618 for aperiod of at least four h prior to test.12.2 Standard TemperatureUnless otherwise specified,the tests sh
33、all 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 Dimensional InspectionEach of thesample PTFE sheets or mo
34、lded 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 interpreted as neither affecting theporosity nor soundness o
35、f 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 with TestMethod D 638 except as follows:13.2.1 Cut five m
36、icrospecimens 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 cardboardsuch as that used in a tabulating machine between said hardsurface and sampl
37、e. Remove any tool marks resulting fromsample preparation which are not essentially parallel to thelong axis of the specimen by light sanding in a directionparallel to such long axis.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-ti
38、on of 22.2 mm 0.875 in. and expressed as a percentage ofthe initial jaw separation.TABLE 3 Nominal Thickness and Tolerances for PTFE SheetsThicknessInchToleranceInchThicknessInchToleranceInchThicknessInchToleranceInch132 +0.01514 +0.030 114 +0.1020.005 0.015 0.051116 +0.01538 +0.038 112 +0.1180.005
39、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 DieISOD329403313.2.4 Alternative SpecimensWhen the shape of thesampl
40、e does not permit making the dumbbell as specified in13.2.1 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
41、circumference of 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 thetube. Turn both inside and outside surfaces with a fine lathefe
42、ed 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 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
43、 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 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 t
44、o 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 removed by light sanding in alongitudinal direction.13.3 Dielectric StrengthDetermine the dielectric strengthin accordance with Test Method D 149 using five specimensand
45、 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 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 stri
46、ps 0.5 60.05 mm 0.020 6 0.002 in. thick shall be used with 1.6-mm116 -in. diameter electrodes 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 accord
47、ance with Method A of Test MethodsD 792. Add two drops of a wetting agent (liquid detergent)9tothe 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 p
48、orosity is to determine that themolding has received adequate pressure and temperaturethroughout.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 t
49、he entire surface on the molding with foldedpaper wiping tissues wet with a suitable cleaner.10Remove theexcess cleaner and permit the surface to dry for at least 5 min.13.5.4 Deposit a film of penetrant10on 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 su
