1、Designation: D 3531 99 (Reapproved 2004)Standard Test Method forResin Flow of Carbon Fiber-Epoxy Prepreg1This standard is issued under the fixed designation D 3531; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、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 SI units are to be regarded asstandard. The values in parentheses are for reference only.1.3 This standard does not purport to address all of thesafet
4、y 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 mi
5、nimumsize of 50-mm (2.0-in.) square 01.57 rad (0 to 90) crosspliedtape is sandwiched between bleeder material and release film.The sandwich is placed in a platen press heated to eithertemperature A, 120C (250F), or temperature B, 175C(350F) or any other temperature specified. The press is closedto p
6、rovide 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
7、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
8、 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 me
9、thods 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, deg
10、ree 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 b
11、y 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.4.5 Glass Bleeder Cloth, Style 1581 or 181.4.6 TFE-Fluorocarbon Coated, Woven Separator Cloth,2porous.4
12、.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).5. Interferences5.1 This test method depends on platen force being suppliedevenly to the specimen. For th
13、is 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 m
14、inimize 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 thicknes
15、s should be1This 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, 2004. Published October 2004. Originallyapproved in 1976. Last previous editi
16、on approved in 1999 as D 3531 99.2DuPont product TX-1040 or equivalent has been found satisfactory for thispurpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.at least five times the tolerance of platen flatness. Specimensthat do
17、 not meet this requirement should have additional plylayers oriented as a repeating unit of the first two plies.5.3 Ply orientation and coupon size directly affects reportedflow. A sample cut with a ply orientation of 0.78 radians (45)will not have the same reported flow as a sample cut with a plyor
18、ientation of 0 radian (0). This is because flow paths arehindered to a different degree based on the different couponsize and orientation.5.4 Temperature should be even across the specimen andwithin the tolerance specified. Temperature influences resinviscosity, which effects flow rate.5.5 Generally
19、, larger coupon sizes reduce lateral flow sinceresin has further to travel to the edge of the specimen. Largercoupon sizes do not greatly influence horizontal flow (withbleeders). However, difficulty in coupon handleability in-creases with increasing coupon size. Also small coupon size of50 mm (2.0
20、in.) square is felt to be the minimum coupon size.A maximum practical size is 100 mm (4.0 in) square.5.6 The matching of angles and footprint from one ply to thenext is critical. Flow differences may be found if the ply layersdo not superimpose on top of each other or are aligned with anangle bias.5
21、.7 It is recommended that the heated platens remain closedunder pressure until resin gelation occurs. Shorter times maycause some of the flowed resin to associate back with thesample rather than the bleeder cloth. Leaving the sample in thepress after gelation has no effect on flow results.6. Test Sp
22、ecimen6.1 A minimum of three specimens shall be tested for eachsample.6.2 The test specimen shall consist of two plies, one at 0 rad(0) and the other at 1.57 rad (90) of 50-mm (2-in.) squareminimum size prepreg sheet.7. Conditioning7.1 Store carbon fiber-epoxy prepreg tape at low tempera-tures, appr
23、oximately 18C (0F), to prolong the usefulness ofthe material. Allow the sealed packages of material to warm toambient temperature before the seal is opened to ensure that thematerial does not absorb moisture from the atmosphere.7.2 Do not expose the material, which usually has somevolatile content,
24、at ambient temperature for long periods oftime before testing is begun.8. Procedure8.1 Cut two pieces 50-mm minimum 61 mm (2.0-in. 60.04 in.) square from the prepreg material. Other sizes may beused, but the two plies shall match within the tolerencesspecified.8.2 Crossply the pieces at 0 to 1.57 ra
25、d (0 to 90) and weighto nearest 0.001 g, recording the weight as W1.8.3 Cut four pieces of Style 1581 glass bleeder cloth of atleast four times the area of the prepeg sample, 100 by 100 mm(4.0 by 4.0 in.) square, minimum.8.4 Cut two pieces of porous TFE-fluorocarbon separatorcloth to the same size a
26、s the bleeder cloth, 100 by 100 mm (4.0by 4.0 in.) square, minimum.8.5 Cut two pieces of release film minimum of 150 mm (6.0in.) square.8.6 Prepare the specimen assembly as follows:8.6.1 Place a 150- by 150-mm (6.0- by 6.0-in.) square pieceof release film on a clean work surface.8.6.2 Apply two piec
27、es of bleeder cloth centered upon the150-mm (6.0-in.) square of release film.8.6.3 Place one piece of porous separator cloth on top of andwith the edges aligned to the edges of the glass bleeder cloth.8.6.4 Place the 50-mm (2.0-in.) square test specimen on thecenter and parallel with the edges of th
28、e porous separator cloth.8.6.5 Cover the specimen with another piece of porousseparator cloth.8.6.6 Cover the assembly with two pieces of the bleedercloth aligned with the edges.8.6.7 Complete the assembly by covering it with a 150-mm(6.0-in.) square piece of release film. All edges should bealigned
29、 and centered on the sheets.8.6.8 Weigh the specimen assembly to nearest 0.001 g andrecord as W2.8.6.9 Insert the assembly into a platen press preheated toeither of the test temperatures (A or B) 63C (65F) or anyother temperature specified. Record the actual platen tempera-tures. Cure this assembly
30、for the gel time recommended by thematerial supplier. Apply pressure of 700 (670) kPa (100 6 10psi) within5sofclosing platens and starting timer. Cure thisassembly for the gel time recommended by the materialsupplier.8.6.10 Remove the layup assembly from the press.8.6.11 Allow assembly to cool to ro
31、om temperature, re-weigh to nearest 0.001 g, record as W3.8.6.12 Separate the resin saturated bleeder materials fromthe composite specimen. Use care in separating the separatormaterial and the specimen to avoid loss of fiber material.8.6.13 Reweigh the specimen to the nearest 0.001 g andrecord as W4
32、.9. Calculation9.1 Calculate the resin flow, RF, as a weight percent of theoriginal prepreg specimen as follows:RF,%5W12 W4W13 100 (1)where:W1= weight of the prepreg specimen, g andW4= weight of the specimen after flow test, g.9.2 Alternatively the resin flow may be calculated as aweight percentage
33、of the volatile-free prepreg, namely:RF volatile2free!,%5W12 W22 W3! 2 W4W12 W22 W3!3 100 (2)where:W2= original weight of specimen assembly, g andW3= weight of specimen assembly after heating, g.10. Report10.1 The report shall include the following:D 3531 99 (2004)210.1.1 Complete identification of
34、the material, including thefiber type, fiber manufacturer, fiber treatment, resin identifica-tion, resin manufacturer, and manufacturer of the prepregmaterial,10.1.2 Ply orientation and stacking sequence,10.1.3 The resin flow in weight percent for each specimenand the average resin flow,10.1.4 The a
35、ctual test temperature,10.1.5 The cure time used, and,10.1.6 Deviations to this method if any.11. Precision and Bias11.1 PrecisionThe precision, defined as the degree ofmutual agreement between individual measurements, can beestimated from the results of a round robin conducted onsamples of prepreg
36、by four laboratories, each laboratorymaking three measurements on each sample. The coefficient ofvariation for the total of twelve measurements having a meanresin flow of 26.1 % was 11.2 %. No modern measure ofprecision is available.11.2 BiasNo estimate of bias can be offered as noaccepted reference
37、 level is available.12. Keywords12.1 carbon fiber-epoxy prepreg; resin flowASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity
38、 of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments
39、 are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not
40、received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3531 99 (2004)3
