ASTM D4776-98
(Test Method)Standard Test Method for Adhesion of Tire Cords and Other Reinforcing Cords to Rubber Compounds by H-Test Procedure
Standard Test Method for Adhesion of Tire Cords and Other Reinforcing Cords to Rubber Compounds by H-Test Procedure
SCOPE
1.1 This test method covers the measurement of adhesion of reinforcing cords that are bonded to rubber compounds. This test method is applicable to textile cord structures from both natural and manmade fibers, other than steel. For adhesion testing of steel tire cords, refer to Test Method D 2229.
1.2 This test method is primarily used to evaluate tire cords, using a suitable tire cord adhesive and a suitable rubber compound. This test method is also used to evaluate (1) tire cord adhesives, and (2) the process of adhesive reaction on the cord using one consistent form of tire cord and one consistent rubber compound. This test method may be used to evaluate cords in industrial hose and belting products and other cord reinforced rubber products.
1.3 This test method is written in SI units. The inch-pound units which are provided in this test method are not necessarily exact equivalents of the SI units. Either system may be used in this test method.
1.4 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
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Standards Content (Sample)
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Designation:D4776–98
Standard Test Method for
Adhesion of Tire Cords and Other Reinforcing Cords to
Rubber Compounds by H-Test Procedure
This standard is issued under the fixed designation D 4776; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D 4393 TestMethodforStrapPeelAdhesionofReinforcing
Cords or Fabrics to Rubber Compounds
1.1 This test method covers the measurement of adhesion of
reinforcing cords that are bonded to rubber compounds. This
3. Terminology
test method is applicable to textile cord structures from both
3.1 Definitions:
natural and manmade fibers, other than steel. For adhesion
3.1.1 adhesion, n—the property denoting the ability of a
testing of steel tire cords, refer to Test Method D 2229D 2229.
material to resist delamination or separation into two or more
1.2 This test method is primarily used to evaluate tire cords,
layers.
using a suitable tire cord adhesive and a suitable rubber
3.1.2 adhesion, n—in tire fabrics, the force required to
compound. This test method is also used to evaluate (1) tire
separate a textile material from rubber or other elastomer by a
cord adhesives, and (2) the process of adhesive reaction on the
definite prescribed method.
cord using one consistent form of tire cord and one consistent
3.1.3 curing, n—see the preferred term vulcanization.
rubber compound. This test method may be used to evaluate
3.1.4 industrial yarn, n—a yarn composed of continuous
cords in industrial hose and belting products and other cord
filaments, usually of high breaking tenacity, produced with or
reinforced rubber products.
withouttwist,andintendedforapplicationsinwhichfunctional
1.3 This test method is written in SI units. The inch-pound
properties are of primary importance; for example, in reinforc-
units which are provided in this test method are not necessarily
ing material in elastomeric products (tires, hose, belting), in
exact equivalents of the SI units. Either system may be used in
protective coverings, and in cordage and webbing, etc.
this test method.
3.1.4.1 Discussion—For example, in reinforcing material in
1.4 This standard does not purport to address all of the
elastomeric products (tires, hose, belting), in protective cover-
safety concerns, if any, associated with its use. It is the
ings, and in cordage and webbing, etc.
responsibility of the user of this standard to establish appro-
3.1.5 reinforcing cord, n—a cord made from industrial
priate safety and health practices and determine the applica-
yarns and used to provide added support to other materials,
bility of regulatory limitations prior to use.
suchastires,hose,belting,protectivecoverings,webbings,etc.
2. Referenced Documents 3.1.6 rubber, n—a material that is capable of recovering
from large deformations quickly and forcibly, and can be, or
2.1 ASTM Standards:
already is, modified to a state in which it is essentially
D76 Specification for Tensile Testing Machines for Tex-
2 insoluble (but can swell) in boiling solvent, such as benzene,
tiles
methylethyl ketone, and ethanol-toluene azeotrope.
D 123 Terminology Relating to Textiles
3 3.1.7 rubber compound, n—as used in the manufacture of
D 1566 Terminology Relating to Rubber
rubber articles, an intimate mixture of elastomer(s) with all the
D 2138 Test Methods for Rubber Property—Adhesion to
materials necessary for the finished article.
Textile Cord
3.1.8 cord, n—a twisted or formed structure composed of
D 2229 Test Method for Adhesion Between Steel Tire
one or more single or plied filaments, strands, or yarns of
Cords and Rubber
organic polymer or inorganic materials.
3.1.8.1 Discussion—For the manufacture of pneumatic tires
or other industrial fabrics, the direction of twist used to
ThistestmethodisunderthejurisdictionofASTMCommitteeD-13onTextiles
combine the single or plied yarn elements into a cord construc-
and is the direct responsibility of Subcommittee D13.19 on Tire Cord and Fabrics.
tion is in the direction opposite to that used in the yarns.
Current edition approved March 10, 1998. Published June 1998. Originally
published as D 4776 – 88. Last previous edition D 4776 – 96.
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 09.01.
4 5
Discontinued 1990—Replaced by D 4776, D 4777. Annual Book of ASTM Standards, Vol 07.02.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D4776–98
Frequently, tire and other reinforcing cords consist of a single
yarn strand having little or no twist. These cords as well as
single monofilaments, are used synonymously with twisted and
plied cords in this test method.
3.1.9 vulcanization, n—an irreversible process, usually ac-
complished through the application of heat, during which a
rubber compound through a change in its chemical structure
(for example, cross-linking) becomes less plastic and more
resistant to swelling by organic liquids, and elastic properties
are conferred, improved, or extended over a greater range of
temperature.
3.1.10 For definitions of other textile terms used in this
standard, refer to Terminology D 123D 123. For definitions of
other terms relating to rubber, refer to Terminology
D 1566D 1566.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 H-test adhesion—as used in this test method, the force
to extract either end of a textile cord structure that is embedded
in a rubber compound under specified conditions.
4. Summary of Test Method
4.1 A cord specimen is sandwiched between two layers of
rubber compound test stock in a form resembling an “H,”
placed in a heated mold, and cured at a specified temperature
and pressure. The test specimen sandwich is then cut to create
an H-test specimen consisting of a single cord with each end
embedded in the center of a tab end of the rubber test block
(Fig. 1). The test specimen is placed in the grips of the tensile
tester, and then the grips are separated. The maximum force
obtained is the H-test adhesion force.
FIG. 1 H-Test Specimen
5. Significance and Use
5.3 This test method is designed to test the adhesion of
5.1 Test Method D 4776 for the determination of the H-test
textiles that are bonded to rubber compounds. Variables that
adhesion of reinforcing cords to rubber compounds may be may contribute to differences in results of this test method
used for the acceptance testing of commercial shipments of
include adhesive type, adhesive application procedure, adhe-
reinforcing cords but caution is advised since information sive cure, fiber type, construction of cords, rubber type, rubber
about between-laboratory precision is incomplete. Compara-
cure, and rubber thickness.
tive tests as directed in 5.1.1 may be advisable. 5.3.1 The deleterious effect of ozone in combination with
5.1.1 In cases of dispute arising from the differences in atmospheric moisture on the ability of adhesives to bond with
reported test results when using Test Method D 4776 for rubber requires assiduous protection of cords prior to embed-
acceptance testing of commercial shipments, the purchaser and
ment.
the supplier should conduct comparative tests to determine if 5.4 The expected range of values which characterize accept-
there is statistical bias between their laboratories. Competent
able adhesion can be determined in any cord-rubber combina-
statistical assistance is recommended for the investigation of tion with experience. For this reason, the purchaser normally
bias.As a minimum, the two parties should take a group of test
establishes a minimum level of adhesion to be obtained by the
specimens which are as homogeneous as possible and which supplier in either the supplier’s laboratory or the purchaser’s
are from a lot of material of the type in question. The test
laboratory using either the supplier’s standard rubber com-
specimens should then be randomly assigned in equal numbers pound or the purchaser’s rubber compound.
to each laboratory for testing.The average results from the two 5.5 Other procedures for testing adhesion of cords to rubber
laboratories should be compared using Student’s t-test for compounds are available, such as Test Methods D 4393 or
unpaired data and an acceptable probability level chosen by the D 2138D 4393D 2138. These procedures have been used ex-
two parties before testing begins. If a bias is found, either its tensively in the trade for acceptance testing. The decision on
cause must be found and corrected or the purchaser and the which test procedure to use is determined by agreement
supplier must agree to interpret future test results in light of the betweenthepurchaserandsupplierbasedonhistoricaldataand
known bias. experience of the contractual parties. Results obtained by any
5.2 This test method is used to measure the force required to of these methods cannot be used interchangeably since there is
extract the cord from a rubber compound test block. no overall correlation between them.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D4776–98
6. Apparatus and Materials
6.1 Tensile Testing Machine—Although a constant-rate-of-
extension (CRE) tensile testing machine is preferred, a
constant-rate-of-traverse (CRT type, pendulum type) may be
used. The specification and methods of calibration and verifi-
cation of these machines shall conform to Specification
D76D76. The testing machine shall be equipped with an
autographic recorder (rectilinear coordinates preferred) or an
interface computer. There is a distinct difference between the
CRE and CRT type testing machines. Consequently, they
cannot be used interchangeably unless a mathematical corre-
lation has been established and agreed upon by the purchaser
and supplier.
6.2 Curing Press, capable of exerting a ram force of 135 kN
(30 000 lbf), equipped with 300 by 300 mm (12 by 12 in.)
platens or larger, and capable of a platen temperature control
within 63°C (65°F) of the temperature specified for curing
the rubber compound.
6.3 Molds—The design of the molds shall be as shown in
Fig. 2. The dimensions of the test specimen are controlled by
the specifications and tolerances of the mold. The dimensions
of the mold (6.40 mm [0.250 in.] embedment) in Fig. 2a shall
be used for cords with a dtex of 1100/2 or less.The dimensions
of the mold (9.52 mm [0.375 in.] embedment) in Fig. 2b shall
NOTE 1—The mold as shown will produce 30 specimens. It may be
be used for cords with a dtex larger than 1100/2. The slot size
fabricated to produce a larger or smaller number, but the dimensions that
for each mold shall be 1.17 mm 6 0.13 mm (0.46 in. 6 0.005
govern the specimen size shall not be altered.
in.).
NOTE 2—A mold cover plate must be provided. It should be 9.5 mm
6.4 Specimen Grips—The design of the specimen grips
(.38in.)thickandthesameoutsidedimensions(“K”and“L”)asthemold.
shall be as shown in Fig. 3. Two grips are required.
NOTE 3—Mold dimension tolerances are XX.X mm 6 .3 mm (XX.XX
6.5 Tensioning Masses—The masses may be of the hook
in. 6 .01 in.) or XX.XX mm 6 .13 mm (XX.XXX in. 6 .005 in.).
type, or designed in such a manner that they can be clamped to
Dimension 2a 2b
the cord. In any event, the total mass shall be 50 g. mm in. mm in.
A 12.70 .500 15.88 .625
6.6 Sheeted Rubber Compound, (sometimes called skim
B 17.5 .69 17.5 .69
stock), supported on a non hygroscopic backing, such as a
C 6.35 .250 9.52 .375
plasticizer-free plastic material. Polyethylene film has been
D 3.17 .125 3.17 .125
E 34.9 1.38 34.9 1.38
found to be satisfactory. The thickness of the rubber stock
F 25.40 1.000 25.40 1.000
required to fill the mold properly shall be determined by
G 25.4 1.00 25.4 1.00
experience.Asaguide,thethicknessoftherubberstockshould H 1.17 1.046 1.17 .046
J 6.40 .250 6.40 .250
be not less than 8 % greater than one-half of the mold cavity
K 149.2 5.88 177.8 7.00
depth. In any event, the thickness is agreed upon between the
L 9.5 .38 9.5 .38
purchaser and supplier. M 196.8 7.75 196.8 7.75
6.6.1 Rubber stock properties are best maintained by stor-
FIG. 2 Mold for H-Test
age in a cool, dry atmosphere. Excessive rubber stock moisture
may lower adhesion of some fiber/rubber composites. Storage
6.10 Gloves, of temperature resistant material.
at 25 6 2°C (77 6 4°F) and 30 to 50 % relative humidity has 7
6.11 Mold Release, for ease of specimen release from
been found satisfactory.
mold.
6.6.2 Rubber compounds exhibit wide variations in shelf
life (properties suitable for good adhesion results) dependent 7. Sampling
upon both composition and storage condition. Rubber com-
7.1 Lot Sample—As a lot sample for acceptance testing,
pounds are usually replaced after three months; however, some
take at random the number of primary sampling units directed
may require replacement within a few weeks. In any event,
in an applicable material specification or other agreement
storage conditions and shelf life should be specified by the
between the purchaser and the supplier. Consider shipping
supplier of the rubber compound.
cases of cord to be the primary sampling units. Exercise
6.7 Timers, having 60 min capacity, ⁄2 min intervals.
caution in sampling and handling so that samples receive
6.8 Marking Pen, silver ink for rubber.
minimum exposure to ambient atmosphere and light prior to
6.9 Shears, for trimming.
“Krylon” No. 1349 Industrial Lube, available from Borden, Inc., Columbus,
Available from Fisher Pen Co., Forest Park, IL. OH has been found satisfactory for this purpose.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D4776–98
8.3 Remove the protective film from the rubber test strips,
then place the individual rubber test strips in the mold cavities
with the protective film side on top.
8.4 Place the cords in the cord slots by cutting cord test
specimens allowing sufficient overhang for masses and tie a
knot in both ends. Take care to prevent the loss of cord twist.
The portion of the cord that is embedded in rubber must not be
touched by the bare hand. Attach a 50 g mass on one knotted
end of the test cord. Two cords may be tie
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