ASTMD4745.pdf

/ITT _tlH|ilp Designation:D 4745-06(lltl.Vltlalt,NTE3,tATONALStandard Specification for1.Scope*l.l This specification covers polytetrafluoroethyleneGTFE)filled molding compounds made with virgin PTFEresins defined in Specification J-)4$94,except Types I,IY Vand VI.Norl;l-This specifioation can be used as a model lor other PTFEcompounds having particulate fillers that can survive the sinteringtemperatures of FrlltrE as can those listed in this specification.Thisspecilication is restricted to virgin PTtrE base resin for technical leasons.Recycled or reprocessed matedal cannot be processed successlully.Nors 2-The properties measured on commercially labricated partsrnay differ frorn the listed values for santples prepared by the proceduresgiven in this specification,depending on part geomelry and processingparameters.Nors 3-There is no ISO equivalent to this specification.1.2 The values stated in SI units are to be regarded asstandard.1.3 The following statement applies to the test methodportion,Section 1 j,of this specification:This stundard dctesnat purport to address all of the sufery concerns,if any,associated*ith its use.If is the responsibilitt of the user ttf this,ttandatd to establi,sh ctppropriate safe4t 6714 heaLth practice,sand determine the applicabilin-o.f regulatory Limitations priorta,use.See i.5 and Nalc.1 itrr a specific warning statement.2.Referenced Documents2.1 ASTM Stundurtls:2I)L:1S Practice lbr Conditioning Plastics for TestingI.):.8 Test Method for Tensile Properties of Plasticsl.)l*)Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by Displacementl)8Bt Terminology Relating to PlasticsI This speciication is under the.jurisciiction ol ASTM Ci:mmittee I)20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThernloplasficMaferials.Current edition approved Dec.l.2006.Published December 2006 Originallyapproved in 1991.Last previous edition approved in 2001 as D4745-01I For referenced ASTM standards.visit the ASTM website.www.astnl.org,orcontact ASTM Customer Service at sewiceasttrt.org,Por Annuol Rook of ASTMStandarcls volLrme infbrmation,refer to the standards Documenl Strmmary page onthe ASTM website.l)160 Terminology for Abbreviated Terms Relating toPlasticsD l8t-5 Test Methods for Apparent Density,Bulk Faotor,and Pourability of Plastic Materials).189 Practice for Packaging/Packing of Plasticstli.$8q4 Speciication for Polytetrafluoroethylene(PTFE)Cranular Molcling and Ram Extrusion MaterialsD 5140 Guide fbr Writing Material Standards in the Clas-sifrcation D 4000 FormatE I I Speciflcation for Wire Cloth and Sieves for TestingPurposesE 691 Practice for Condrrcting an Interlaboratory Study toDetermine the Precision of a Test MethodIEEE/ASTM SI-10 Standard for Use of the Internationalsysrem of units(SI):The Modern Metric systenrl3.Terminology3.1 DeJinitions-The terminology given in Terminologyi-$itr is applicable to this specification unless otherwisespecifiecl.3.2 Definitiorts of Terms Specifc to This Standard:3.2.1 bulk density,n-the mass in kilograms per cubicmetre oi resin compound measured under the conditions of thetest.3.2.2 filled compound,n-blend of PTFE resin as the rnatrixand particulate fillers,generally glass,other inorganic,metal-lic,or polyneric materials that withstancl the sintering tem-perature of PTFE(321 to 380C).3.2.3 free-flow-resins(pelletiz,ed),n-generally made bytreatment of linely divided resins to produce iiee-flowingagglonerates.3.2.4 lot,n-one production run or a uniform blend of twoor more production runs.3.2.5 pigmerfied contpound,n-a compound in which apigrnent is added for colorant purposes only.3.2.6 s t anda rd flov,re s ins(no n p e I le tize d),n-finely di vi dedresin with an average parlicle size less than 100 pm.iAvailable fiom ASTN4 International Heaclctuarters,100 tsanWest Conshohocken.PA 19428Sold loilHS Standards Store Purchase,412573Nol for Resale.02105/2008 07r48i33 lrSTFilled Compounds of Polytetrafluoroethylene(PTFE)Molding and Extrusion MaterialslThis standard is issued under the fixed designation D 4745;the number immediately tbllorving(he Llesignation indicates the year otoriginal adoption or,in the case of revision.the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indrcates an editorial changc since the lasl revision or reapprovalxA Summary of Changes section appears at the end of this standard.Copyright O ASTIM lnternational,1 00 Barr Harbor Drive.PO Box C700,West Conshohocken,PA 1 9428-2959,United States.pyfight ASTM Inlernalional)vided by IHS under license wih ASTMrepfoduclion or nelworking pemitted withoul license from IHSHarbur Drive,($Jp o 474s-ooTABLE 1 TFE Compounds,Type l,Standard Flow(Nonpelletized)Molded Parts(Molded and Sintered)Raw ResinBulk Density,min,g/LSpecilicGravity,SpecificGravity,min maxTensile StrengthElongatron,min,%min,MPamrn,psl123A567815%glass fiber25%glass fiber35%glass fiber5%glass flber and 5%MoS,15 9o glass fiber and 5%MoSz10%graphite15%graphrte25 L carbon and graPhite32 ok ca(bon and graphlte4O/bronze60 k b(onze55 ok brcnze and 5%MoS250%stainless steel4004254503503753503003503255006507005002.1502.1 502.2002.1 502.1502.1 002.1001,9501.9002.9003.8003,5003.2002.252.2502.3002.3002.3002.2002.1002.1 003.2004.0004.0003.60019.615.710.320.717.217,9to.o11.06.917.213.810.317.2284022741500300025002600240Q1 6001 000250020001 50025002502001502502002251008050175140BO1501011IJ3.3 Abbretiations-Lbbreviations are in accordance withTerminology ll i(dX)PTFE is lhe acronym for polytetrailuo-roethylene.4.Classification4.1 This specification covers the following two types ofPTFE compounds:4.1.1 Tr-pe 1-Nonpelletized material,for general-putposecompression molding.4.1.2 hpe/I-Pelletized or free-flowing material for mold-ing.automatic molding,or ram extrusion4.2 Thirteen grades of each type distinguished by the natureof the filler(s)are listecl in Tnbk:s 1-14.3 A one-line system may be used to specily materialscovered by this specification.The system uses predefined cellsto refer to specifii aspects of this specification as the followingillustrates:Specf ication;SPecialBlock:Notes5.Ordering Information5.1 The filled compounds of PTFE uray be ordered using thetype,(see 4.1)and the gracle(see reference lirbi*I and Tabls:),o.*t.y may be orclerecl using the designation of thesuppliers.6.Requirements6.1 The PTFE compounds covered by this specificationshallbeunilbrm(fillerarrdresinparticlesevenlydistributed)and shall contain no foreign material.6.2 The PTFE compounds shall conform to the requtre-ments prescribed iniilb:s l-:i when tested by the proceduresspecifiid herein.1ahlc I andIlrblu:i list recluirements for Typet.lrUc I and f*hlc I reference requirements for Type II6.3 Other PTFE cornpounds are commercially available butare not described in this specification.7.Sampling7.1 Sampling shall be statistically adequate to satisfy therequirements of|3.-18.Number of Tests8.1 Routine lot inspection tests shall consist ofthose carriedout to determine the requirements specified in.Ilii:lc or,lli.llle:.1 depending on type.Periodic tests shall include using all thetests to determine the requirements in lnbl*-1,depending ontype.8.2 The requirements listed inirrlcs-11,as they apply aresufftcient to establish conforrnity of a material to this specifi-cation.Whenthenumberoftestspecimensisnotstatedinthetest rnethocl,single determinations may be made If more thansingle determinations are made on specimens from separatepoiiont of the same sample,the results shall be avelaged Theiingle or average result shall conform to the requirementsprescribed in this specification.9.Test Specimens9.1 Test specimetrs shall be cut from billets molded inaccordance with the iollowing procedures An acceptablealternate procedure for molding the test plaque is described inSpecification D+891Example:SpecificationD 4745-974.3.1 For this example,the line callout would be Specifica-tion D 4145-91,II 2,and would specify a pelietized orfree-flowing fi llecl composition of polytetrafluoroethylene thathas all of tle proper-ties listed for that type,and grade in theappropriate specided properlies,tables,or both,in the specifi-coilo,i iOentltted.A comma is used as the separator between thestanclard number ancl the type.Separators are not lleededbetween the type.grade,and classa A provision for specialnotes is inctuitet so that other information can be providecwhen required.An example woull be in SpecificationD3295_iJla where dirnensions and tolerances ae specifiecl1br each AWC size within type and class When special notesare used,they should be preceded by a commaa See the,STM Form antl Stvle ManuaL available fronr ASTMovnqhl ASTM Inlernalional)vd;d by IHS under lcense wilh ASTi4;e;roou;tioo o.neuorklng permineo wilhoul lcense irom lHsaSold to:lHS Slandards Slore Purchas,412573Nol for Resale,02105/2008 07r48 33 MSTI Ieadq urrters($P o 4r45-ooTABLE 2 TFE Compounds,Type ll,Free-Flow(Pelletized)Molded Parts(Molded and Sinlered)Raw ResinBulk Density,min,g/LSpecilic Gravity,Speciic Gravitymin maxTensile StrenglhElongation,min,%min,MPamrn,psl134567I910.111315%glass fiber25%glass fiber35%glass fiber5%glass fiber and 5%MoSa15%glass fiber and 5%MoSz10%graphite15%graphite25 k carbon and graphite32 7 ca(bon and graphite4O/bronze60 7o bronze55 1o brcnze and 5%MoS?50%stainless steel625625650575600600DCU5005007509009008502.1502.1502.2002.1502.1 502.1002.1 00L9501.9002.9003.8003.5003.2002.252.2502.3002.3002.3002.2202.2002.1002.1 003.2004.0004.0003.60013.8?.48.313.813.810.38.36.913.810.36.913,820001 8001 2002500200020001 50012001 00020001 5001 00020002001801002201801501002020856060100TABLE 3 Required Filler ContentMass,%Tolerance,-r:,7o1251340to341o2526 to 6061 10 759.2 Test Billets:9.2.1 Prior to molding,screen the material through a2.0-mm hand sieve.9.2.2 Preform solid test billets in a mold(see l-i3 l)h-avinga cross-seclional area not greater than 258 cm2 4 in2 andof sufficient height to contain the sample Clearance should besultcient o ensure escape of entrapped air during pressingThe billet length may be varied in accordance with the amountof testing to be clone.A mold length of 250 mm 98 inprocluces:a billet approximately 75 mm 12 Lo 3 inl lottgFowder-charge weight may be variecl in accordance with thedensityofthematerial.ThebilletlerrgthshouldnotexceedT5mm 3 in.9.2.3 Assemble the mold.Add the resin to the mold takingcare not to ill within 13 mn 0.5 in of the top of the cavitylnseft the top plug and apply hand pressule,making cer-tain thatthe pusher is centered in the mold Place the mold in ahyclraulic press ancl remove the support ring or spacers Do notallow the two end plugs to bottom on the mold shell Apply aninitial load to the mold of 3.45 MPa 500 psi+l0 o/o and holdfor 1 to 2 min lncrease the loacling smoothly to the finalpre forming pressure in 3 to 5 nin Use 207 MPa 3000 psi|foriompounds containing up to 4 7c by weight filler Use 345MP;t5000 psil fbr compounds containing 5 to 25 a/o by weightor less filler and 6it9 MPa ti0000 psil for composite corn-pounds containing more than 26 o/o fillet Hold under maximump,.u.tbr2to5min.Releasethepressuregraduallywithclutapparellt movement of the press platens Then open the pressI.nlouthetoppusherfrclmthemoldandforcetheprefortnverticallyclutoftherncllcl,rrsingacontinuclus,smoothmove-ment.9.2.4 Place the preform in a sintering oven and suter lnaccordancewiththeproceduresin!iihlt:lUseProcedureBfor compounds containing rrolybdenum disulfide fillerpynghl ASTM Inlemalional)vded by IHS under lcense wilh ASTlvlfepfod;ction or nelworking pormifled withoul license from IHSSTEEL UOLD 4 in2 ctoss seclionale rea.AgprcriBtely 57 612.25 ir.l l.D305 m(U ir.)to 380 m(15 ln.lons)FlG.1 Preforming of PTFE ComPosite Test BilletTABLE 4 Sintering Procedures for Test BilletsProcedure AProcedure Blnitial temperature,C(+)ARate o heating,C/h fF/hlHold temperature,C FHold time,minRate ot cooling,C/h f F/hlFinal temperature,C fFlTime to cool to room temperature,hA Oven can be opened safely at these temperalures9.3 Sectioning,Test Billet:9.3.1 Remove and discard the top and bottom 2-mm%o insection of the billet.Obtain transverse test specimens frclm asnear the center of the billet as possibie9.3.2 Prepate flve test specimens,1-f 025 mm 0040 t0.010 in.l in thickness fbr the determination of tensile strengthancl elongation and cut a piece of suitable thickness for densitymeasurements.This piece should be approximately cubical in3Sold to:lHS Standards Store Purchas 412573Noi for Resale,02/05/2008 07:48r33 MSTAmbient60.t 5 108:l370:t 6 698:t24Ar560:t 5 l108ri95 i 6 203:f24Ambient60t51108r360:!6 L6B0 I1019l 60r101 95:i240:[phone] I24101101el101,($fp o Azls-aoshape,weighing at least l0 g.All sttrfaces must be smooth.Take care to avoid wedge-shape cuts.9.4 The altenrative test billet is described in SpecificationD.3HtJ4.9.5 Safety Warning-At normal processing temperatures,PTFE liberates vapors that may be harmful.Provide adequateventilation in areas where PTFE cotnpounds are exposed toelevated ternperatures.Avoid contaminating smoking materialswith PTFE compounds.10.Conditioning Test SpecimensI0.1 For density and tensile prclperties the test specirnensshall be conditioned in accordance with Procedure A ofPractice D 6t8 for a period of at least 4 h prior to test.L1.Test Conditionsl1.l Tests shall be conducted aL23+2C V3Ar 4F1.Since the resin does not absorb water,the maintenance o1constant humidity during testing is not required12.Test Methods12.1 Filler Content.12.1.1 Scope-This burn-out procedure for filler contenlmay be used for determining the amount of a filler in acompound.The procedure shall be carried out in an inertatmosphere,especially when fillers that react with PTFE andoxygerl in the air are present.This reaction produces volatileproducts that cause incorrect results.12.1.2 The equipment used is a tube Iurnace suitable lor useat 680-r 25C 1250-r 50F1.The lurnace should have acombustion tube made of ceramic or Vycor glass Two nickelor platinum combustion boats should be used to enable the testto run in duplicate.A system is needed to supply a constantpurge of dry nitrogen through the furnace at a rate of 10 to 50nil/min.12.1.3 Scrub the pyrolysis gases with a base,such as a dih-rtesolution of sodium hvdroxide,and vent to the outside atmo-sphere.NorE 4-Take care to avoid leakage of fumes into the work area.Takeprecautions to avoid the inhalation of,or exposure to gases frorn thepyrolysis sincc these gases may be hazardous.12.1.4 Add approximately 2 g of the sample to each of thecombustion boats,using standard quantitative labclratoryweighing practices.Place boats and samples into the furnace.Heat and hold at 680-f 25C fi250 j-50Fj until completedegradation of the PTFE has occumed.One hour is sufficienttime.Maintain an inert atmosphere during the heating,pyroly-sis,and cooling steps.Calculate the percentage of hller as thenet weight of the residue multiplied by 100,divi