ASTM_D_3531_-_D_3531M_-_11.pdf

Designation:D3531/D3531M11Standard Test Method forResin Flow of Carbon Fiber-Epoxy Prepreg1This standard is issued under the fixed designation D3531/D3531M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination of the amountof resin flow that will take place from prepreg tape or sheetunder given conditions of temperature and pressure.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.2.1 Within the text,inch-pound units are shown in brack-ets.1.3 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 regulatory limitations prior to use.2.Summary of Test Method2.1 A weighed specimen consisting of two plies a minimumsize of 50-mm 2.0-in.square,oriented in a 0/90 crossplyconfiguration,and sandwiched between bleeder material andrelease film.The sandwich is placed in a platen press heated toeither temperature A,120C 250F,or temperature B,175C350F or another specified temperature.The press is closed toprovide a pressure of 700 kPa 100 psi.The pressure is heldfor 15 min or until the resin gels.The cooled sandwichassembly is removed and the resin that has flowed to the edgesof the specimen is removed and the specimen reweighed.Thechange in weight is expressed as a percent of the originalweight and reported as percent flow.3.Significance and Use3.1 This test method is used to obtain the resin flow ofcarbon fiber-epoxy prepreg tape or sheet material.It is suitablefor comparing lots of material of supposedly the same charac-teristics and also for comparative evaluation of materialsproduced by different vendors using different resin-fiber com-binations.3.2 Composite parts are laminated from prepreg material atvarious pressures and temperatures.Production process designwill require a flow test be run at a temperature and a pressureclose to that of the actual molding conditions.All methods ofmeasuring resin flow are dependent on the size and geometryof the specimen.This test method uses the smallest quantity oftape that will give reproducible results.3.2.1 The percent resin flow of a single fiber and resinsystem at a temperature and pressure varies with the volatilecontent,degree of advancement of epoxy resin,and with theresin content of the prepreg tape or sheet.3.2.2 As volatile content and degree of resin cure(advance-ment)change with time,this test method is useful in comparingthe life of prepreg tape and sheet.4.Apparatus4.1 Cutting Template,square metal,50 by 50 mm 2.0 by2.0 in.,minimum.4.2 Cutting Template,metal,100 by 100 mm 4.0 by 4.0in.,minimum.4.3 Cutting Knife,single edge.4.4 Analytical Balance capable of weighing to the nearest0.001 g 0.000035 oz.4.5 Glass Bleeder Cloth,Style 1581 or 181.4.6 TFE-Fluorocarbon Coated,Woven Separator Cloth,2porous.4.7 Release Film of 0.03 to 0.06 mm 0.001 to 0.002 in.thickness polyester,aluminum,etc.4.8 Platen Press,capable of being heated to 175 6 3C 3506 5F and capable of applying 4000 N 900 lbf.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.03 onConstituent/Precursor Properties.Current edition approved Oct.1,2011.Published November 2011.Originallyapproved in 1976.Last previous edition approved in 2009 as D3531 99(2009).DOI:10.1520/D3531_D3531M-11.2DuPont product TX-1040 or equivalent has been found satisfactory for thispurpose.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Interferences5.1 This test method depends on platen force being suppliedevenly to the specimen.For this to be done,the platen mustload evenly across its surface and not point load to the point ofinitial contact.When bleeder materials are used on the top andbottom of the specimen,the effect of uneven pressure applica-tion is less pronounced than if no bleeder materials are used.Bleeders tend to minimize pressure effects,since if resin flowsinto the bleeder it will do so within a broad pressure range.Sometimes,platen pressure needs to be increased gradually toassure even loading.5.2 The platen flatness must be sufficient for the specimen toload evenly.For this reason the specimen thickness should beat least five times the tolerance of platen flatnes