1、Designation: D3531/D3531M 16Standard 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 revisio
2、n. 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 U.S. Department of Defense.1. Scope1.1 This test method covers the determination of
3、 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, e
4、achsystem 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
5、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. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD3878 Terminology for Composite Mate
6、rials3. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites. TerminologyD883 defines terms relating to plastics. In the event of aconflict between terms, Terminology D3878 shall have prece-dence over other standards.3.2 Symbols:3.2.1 RFresin
7、flow3.2.2 W1weight of the prepreg specimen prior to flow test3.2.3 W2weight of the specimen assembly prior to heating3.2.4 W3weight of the specimen assembly after heating3.2.5 W4weight of the prepreg specimen after flow test4. Summary of Test Method4.1 Aweighed specimen consisting of two plies a min
8、imumsize 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 to
9、provide 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 a
10、nd reported as percent flow.5. Significance and Use5.1 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
11、by different vendors using different resin-fiber com-binations.5.2 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 met
12、hods 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.5.2.1 The percent resin flow of a single fiber and resinsystem at a temperature and pressure varies with the volatilecontent, degr
13、ee of advancement of epoxy resin, and with theresin content of the prepreg tape or sheet.5.2.2 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.1This test method is under the jurisdiction of ASTM C
14、ommittee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.03 onConstituent/Precursor Properties.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1976. Last previous edition approved in 2011 as D3531 11. DOI:10.1520/D3531_D3531M-16.2F
15、or referenced ASTM standards, 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
16、0, West Conshohocken, PA 19428-2959. United States16. Interferences6.1 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
17、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 b
18、e increased gradually toassure even loading.6.2 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 flatness. Specimensthat do not meet this requirement should have additional plylayers ori
19、ented as a repeating unit of the first two plies.6.3 Ply orientation and coupon size directly affects reportedflow. A sample cut with a ply orientation of 45 will not havethe same reported flow as a sample cut with a ply orientationof 0. This is because flow paths are hindered to a differentdegree b
20、ased on the different coupon size and orientation.6.4 Temperature should be even across the specimen andwithin the tolerance specified. Temperature influences resinviscosity, which effects flow rate.6.5 Generally, larger coupon sizes reduce lateral flow sinceresin has further to travel to the edge o
21、f 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 in. square is felt to be the minimum coupon size.A maximum practical size is 100 mm 4.0 i
22、n square.6.6 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.6.7 It is recommended that the heated platens remain closedunder pressure until resin gelatio
23、n 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.7. Apparatus7.1 Cutting Template, square metal, 50 by 50 mm 2.0 by2.0 in., minimum.7.2 Cutting Templat
24、e, metal, 100 by 100 mm 4.0 by 4.0in., minimum.7.3 Cutting Knife, single edge.7.4 Analytical Balance capable of weighing to the nearest0.001 g 0.000035 oz.7.5 Glass Bleeder Cloth, Style 1581 or 181.7.6 TFE-Fluorocarbon Coated, Woven SeparatorCloth,3porous.7.7 Release Film of 0.03 to 0.06 mm 0.001 to
25、 0.002 in.thickness polyester, aluminum, etc.7.8 Platen Press, capable of being heated to 175 6 3C 3506 5F and capable of applying 4000 N 900 lbf.8. Test Specimen8.1 A minimum of three specimens shall be tested for eachsample.8.2 The test specimen shall consist of two plies, one at 0and the other at
26、 90 of 50-mm 2-in. square minimum sizeprepreg sheet.9. Conditioning9.1 Store carbon fiber-epoxy prepreg tape at lowtemperatures, approximately 18C 0F, to prolong the use-fulness of the material. Allow the sealed packages of materialto warm to ambient temperature before the seal is opened toensure th
27、at the material does not absorb moisture from theatmosphere.9.2 Do not expose the material, which usually has somevolatile content, at ambient temperature for long periods oftime before testing is begun.10. Procedure10.1 Cut two pieces 50-mm 61 mm 2.0-in. 6 0.04 in.square, minimum, from the prepreg
28、material. Other sizes maybe used, but the two plies shall match within the tolerencesspecified.10.2 Crossply the pieces at 0 to 90 and weigh to nearest0.001 g 0.000035 oz, recording the weight as W1.10.3 Cut four pieces of Style 1581 glass bleeder cloth of atleast four times the area of the prepeg s
29、ample, 100 by 100 mm4.0 by 4.0 in. square, minimum.10.4 Cut two pieces of porous TFE-fluorocarbon separatorcloth to the same size as the bleeder cloth, 100 by 100 mm 4.0by 4.0 in. square, minimum.10.5 Cut two pieces of release film minimum of 150 mm6.0 in. square.10.6 Prepare the specimen assembly a
30、s follows:10.6.1 Place a 150- by 150-mm 6.0- by 6.0-in. squarepiece of release film on a clean work surface.10.6.2 Apply two pieces of bleeder cloth centered upon the150-mm 6.0-in. square of release film.10.6.3 Place one piece of porous separator cloth on top ofand with the edges aligned to the edge
31、s of the glass bleedercloth.3DuPont product TX-1040 or equivalent has been found satisfactory for thispurpose.D3531/D3531M 16210.6.4 Place the 50-mm 2.0-in. square test specimen onthe center and parallel with the edges of the porous separatorcloth.10.6.5 Cover the specimen with another piece of poro
32、usseparator cloth.10.6.6 Cover the assembly with two pieces of the bleedercloth aligned with the edges.10.6.7 Complete the assembly by covering it with a150-mm 6.0-in. square piece of release film.All edges shouldbe aligned and centered on the sheets.10.6.8 Weigh the specimen assembly to nearest 0.0
33、01 g0.000035 oz and record as W2.10.6.9 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 for the gel time recommended by thematerial supplier. Apply press
34、ure of 700 670 kPa 100 6 10psi within5sofclosing platens and starting timer. Cure thisassembly for the gel time recommended by the materialsupplier.10.6.10 Remove the layup assembly from the press.10.6.11 Allow assembly to cool to room temperature, re-weigh to nearest 0.001 g 0.000035 oz, record as
35、W3.10.6.12 Separate the resin saturated bleeder materials fromthe composite specimen. Use care in separating the separatormaterial and the specimen to avoid loss of fiber material.10.6.13 Reweigh the specimen to the nearest 0.001 g0.000035 oz and record as W4.11. Calculation11.1 Calculate the resin
36、flow, RF, as a weight percent of theoriginal prepreg specimen as follows:RF,%5W12 W4W13100 (1)where:W1= weight of the prepreg specimen, g oz andW4= weight of the specimen after flow test, g oz.11.2 Alternatively the resin flow may be calculated as aweight percentage of the volatile-free prepreg, nam
37、ely:RF volatile 2 free!,%5W12 W22 W3! 2 W4W12 W22 W3!3100 (2)where:W2= original weight of specimen assembly, g oz andW3= weight of specimen assembly after heating, g oz.12. Report12.1 The report shall include the following:12.1.1 Complete identification of the material, including thefiber type, fibe
38、r manufacturer, fiber treatment, resinidentification, resin manufacturer, and manufacturer of theprepreg material,12.1.2 Ply orientation and stacking sequence,12.1.3 The resin flow in weight percent for each specimenand the average resin flow,12.1.4 The actual test temperature,12.1.5 The cure time u
39、sed, and,12.1.6 Deviations to this method if any.13. Precision and Bias13.1 PrecisionThe precision, defined as the degree ofmutual agreement between individual measurements, can beestimated from the results of a round robin conducted onsamples of prepreg by four laboratories, each laboratorymaking t
40、hree 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.13.2 BiasNo estimate of bias can be offered as no ac-cepted reference level is available.14. Keywords14.1 carbon
41、 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 of any such patent rights, and the riskof
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