ASTM D3531-99

Standard Test Method for Resin Flow of Carbon Fiber-Epoxy Prepreg

SCOPE
1.1 This test method covers the determination of the amount of resin flow that will take place from prepreg tape or sheet under given conditions of temperature and pressure.
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Oct-1999
• ICS: 83.120 - Reinforced plastics
• Technical Committee: D30 - Composite Materials
• Drafting Committee: D30.03 - Constituent/Precursor Properties

Relations

• Replaced By: ASTM D3531-99(2004) - Standard Test Method for Resin Flow of Carbon Fiber-Epoxy Prepreg
• Effective Date: 01-Oct-2004
• Referred By: ASTM D5687/D5687M-20 - Standard Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparation
• Effective Date: 10-Oct-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 3531 – 99
Standard Test Method for
Resin Flow of Carbon Fiber-Epoxy Prepreg
This standard is issued under the fixed designation D 3531; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope measuring resin flow are dependent on the size and geometry
of the specimen. This test method uses the smallest quantity of
1.1 This test method covers the determination of the amount
tape that will give reproducible results.
of resin flow that will take place from prepreg tape or sheet
3.2.1 The percent resin flow of a single fiber and resin
under given conditions of temperature and pressure.
system at a temperature and pressure varies with the volatile
1.2 The values stated in SI units are to be regarded as
content, degree of advancement of epoxy resin, and with the
standard. The values in parentheses are for reference only.
resin content of the prepreg tape or sheet.
1.3 This standard does not purport to address all of the
3.2.2 As volatile content and degree of resin cure (advance-
safety concerns, if any, associated with its use. It is the
ment) change with time, this test is useful in comparing the life
responsibility of the user of this standard to establish appro-
of prepreg tape and sheet.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Apparatus
2. Summary of Test Method 4.1 Cutting Template, square metal, 50 by 50 mm (2.0 by
2.0 in.), minimum.
2.1 A weighed specimen consisting of two plies a minimum
4.2 Cutting Template, metal, 100 by 100 mm (4.0 by 4.0
size of 50-mm (2.0-in.) square 0–1.57 rad (0 to 90°) crossplied
in.), minimum.
tape is sandwiched between bleeder material and release film.
4.3 Cutting Knife, single edge.
The sandwich is placed in a platen press heated to either
4.4 Analytical Balance capable of weighing to the nearest
temperature A, 120°C (250°F), or temperature B, 175°C
0.001 g.
(350°F) or any other temperature specified. The press is closed
4.5 Glass Bleeder Cloth, Style 1581 or 181.
to provide a pressure of 700 kPa (100 psi). The pressure is held
4.6 TFE-Fluorocarbon Coated, Woven Separator Cloth,
for 15 min or until the resin gels. The cooled sandwich
porous.
assembly is removed and the resin that has flowed to the edges
4.7 Release Film of 0.03 to 0.06 mm (0.001 to 0.002 in.)
of the specimen is removed and the specimen reweighed. The
thickness polyester, aluminum, etc.
change in weight is expressed as a percent of the original
4.8 Platen Press, capable of being heated to 175 6 3°C (350
weight and reported as percent flow.
6 5°F) and capable of applying 4000 N (900 lbf).
3. Significance and Use
5. Interferences
3.1 This test method is used to obtain the resin flow of
5.1 This method depends on platen force being supplied
carbon fiber-epoxy prepreg tape or sheet material. It is suitable
evenly to the specimen. For this to be done, the platen must
for comparing lots of material of supposedly the same charac-
load evenly across its surface and not point load to the point of
teristics and also for comparative evaluation of materials
initial contact. When bleeder materials are used on the top and
produced by different vendors using different resin-fiber com-
bottom of the specimen, the effect of uneven pressure applica-
binations.
tion is less pronounced than if no bleeder materials are used.
3.2 Composite parts are laminated from prepreg material at
Bleeders tend to minimize pressure effects, since if resin flows
various pressures and temperatures. Production process design
into the bleeder it will do so within a broad pressure range.
will require a flow test be run at a temperature and a pressure
Sometimes, platen pressure needs to be increased gradually to
close to that of the actual molding conditions. All methods of
assure even loading.
5.2 The platen flatness must be sufficient for the specimen to
load evenly. For this reason the specimen thickness should be
This test method is under the jurisdiction of ASTM Committee D-30 on
Composite Materials and is the direct responsibility of Subcommittee D30.03 on
Constituent/Precursor Properties.
Current edition approved Oct. 10, 1999. Published February 2000. Originally DuPont product TX-1040 or equivalent has been found satisfactory for this
published as D 3531-76. Last previous edition D 3531-76 (1995). purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 3531
at least five times the tolerance of platen flatness. Specimens 8.5 Cut two pieces of release film minimum of 150 mm (6.0
that do not meet this requirement should have additional ply in.) square.
layers oriented as a repeating unit of the first two plies.
8.6 Prepare the specimen assembly as follows:
5.3 Ply orientation and coupon size directly affects reported
8.6.1 Place a 150- by 150-mm (6.0- by 6.0-in.) square piece
flow. A sample cut with a ply orientation of 0.78 radians (45°)
of release film on a clean work surface.
will not have the same reported flow as a sample cut with a ply
8.6.2 Apply two pieces of bleeder cloth centered upon the
orientation of 0 radian (0°). This is because flow paths are
150-mm (6.0-in.) square of release film.
hindered to a different degree based on the different coupon
8.6.3 Place one piece of porous separator cloth on top of and
size and orientation.
with the edges aligned to the edges of the glass bleeder cloth.
5.4 Temperature should be even across the specimen and
8.6.4 Place the 50-mm (2.0-in.) square test specimen on the
within the tolerance specified. Temperature influences resin
center and parallel with the edges of the porous separator cloth.
viscosity, which effects flow rate.
8.6.5 Cover the specimen with another piece of porous
5.5 Generally, larger coupon sizes reduce lateral flow since
separator cloth.
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