1、Designation: D4776/D4776M 10Standard Test Method forAdhesion of Tire Cords and Other Reinforcing Cords toRubber Compounds by H-Test Procedure1This standard is issued under the fixed designation D4776/D4776M; the number immediately following the designation indicates theyear of original adoption or,
2、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.1. Scope1.1 This test method covers the measurement of adhesion ofreinforcing cords that are
3、bonded to rubber compounds. Thistest method is applicable to textile cord structures from bothnatural and manmade fibers, other than steel. For adhesiontesting of steel tire cords, refer to Test Method D2229.1.2 This test method is primarily used to evaluate tire cords,using a suitable tire cord adh
4、esive and a suitable rubbercompound. This test method is also used to evaluate (1) tirecord adhesives, and (2) the process of adhesive reaction on thecord using one consistent form of tire cord and one consistentrubber compound. This test method may be used to evaluatecords in industrial hose and be
5、lting products and other cordreinforced rubber products.1.3 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
6、 from the two systems may result in non-conformancewith the standard.1.4 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
7、applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1566 Terminology Relating to RubberD2229 Test Method for Adhesion Between Steel Tire Cordsand RubberD4393
8、Test Method for Strap Peel Adhesion of ReinforcingCords or Fabrics to Rubber CompoundsD6477 Terminology Relating to Tire Cord, Bead Wire,Hose Reinforcing Wire, and Fabrics3. Terminology3.1 Definitions:3.1.1 For defintions of terms relating to tire cord, bead wire,hose wire, and tire cord fabrics, re
9、fer to Terminology D6477.3.1.1.1 The following terms are relevant to this standard:adhesion, adhesion, in tire fabrics, cord, curing, H-test adhe-sion, industrial yarn, reinforcing cord, rubber, rubber com-pound, as used in the manufacture of rubber articles, vulcani-zation.3.1.2 For definitions of
10、other terms relating to rubber, referto Terminology D1566.3.1.3 For definitions of other textile terms related to textiles,refer to Terminology D123.4. Summary of Test Method4.1 A cord specimen is sandwiched between two layers ofrubber compound test stock in a form resembling an “H,”placed in a heat
11、ed mold, and cured at a specified temperatureand pressure. The test specimen sandwich is then cut to createan H-test specimen consisting of a single cord with each endembedded in the center of a tab end of the rubber test block(Fig. 1). The test specimen is placed in the grips of the tensiletester,
12、and then the grips are separated. The maximum forceobtained is the H-test adhesion force.5. Significance and Use5.1 Test Method D4776 for the determination of the H-testadhesion of reinforcing cords to rubber compounds may beused for the acceptance testing of commercial shipments ofreinforcing cords
13、 but caution is advised since informationabout between-laboratory precision is incomplete. Compara-tive tests as directed in 5.1.1 may be advisable.5.1.1 In cases of dispute arising from the differences inreported test results when using Test Method D4776 foracceptance testing of commercial shipment
14、s, the purchaser andthe supplier should conduct comparative tests to determine ifthere is statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation of1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct
15、 responsibility of Subcommittee D13.19 on Tire Cord and FabricsCurrent edition approved Jan. 1, 2010. Published January 2010. Originallyapproved in 1988. Last previous edition approved in 2004 as D4776 041. DOI:10.1520/D4776-04E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
16、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.bias. As a mini
17、mum, the two parties should take a group of testspecimens which are as homogeneous as possible and whichare from a lot of material of the type in question. The testspecimens should then be randomly assigned in equal numbersto each laboratory for testing. The average results from the twolaboratories
18、should be compared using Students t-test forunpaired data and an acceptable probability level chosen by thetwo parties before testing begins. If a bias is found, either itscause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results in light of thekn
19、own bias.5.2 This test method is used to measure the force required toextract the cord from a rubber compound test block.5.3 This test method is designed to test the adhesion oftextiles that are bonded to rubber compounds. Variables thatmay contribute to differences in results of this test methodinc
20、lude adhesive type, adhesive application procedure, adhe-sive cure, fiber type, construction of cords, rubber type, rubbercure, and rubber thickness.5.3.1 The deleterious effect of ozone in combination withatmospheric moisture on the ability of adhesives to bond withrubber requires assiduous protect
21、ion of cords prior to embed-ment.5.4 The expected range of values which characterize accept-able adhesion can be determined in any cord-rubber combina-tion with experience. For this reason, the purchaser normallyestablishes a minimum level of adhesion to be obtained by thesupplier in either the supp
22、liers laboratory or the purchaserslaboratory using either the suppliers standard rubber com-pound or the purchasers rubber compound.5.5 Another procedure for testing adhesion of cords torubber compounds is Test Methods D4393 . This procedure hasbeen used extensively in the trade for acceptance testi
23、ng.Results obtained by this method cannot be used interchange-ably since there is no overall correlation between them.6. Apparatus and Materials6.1 Tensile Testing MachineAlthough a constant-rate-of-extension (CRE) tensile testing machine is preferred, aconstant-rate-of-traverse (CRT type, pendulum
24、type) may beused. The specification and methods of calibration and verifi-cation of these machines shall conform to Specification D76.The testing machine shall be equipped with an autographicrecorder (rectilinear coordinates preferred) or an interfacecomputer. There is a distinct difference between
25、the CRE andCRT type testing machines. Consequently, they cannot be usedinterchangeably unless a mathematical correlation has beenestablished and agreed upon by the purchaser and supplier.6.2 Curing Press, capable of maintaining a minimum pres-sure of 3.5 MPa 500 psi over the total area of the moldsu
26、rface, equipped with 300 by 300 mm 12 by 12 in. platensor larger, and capable of a platen temperature control within63C 65F of the temperature specified for curing therubber compound.6.3 MoldsThe design of the molds shall be as shown inFig. 2. The dimensions of the test specimen are controlled bythe
27、 specifications and tolerances of the mold. The dimensionsof the mold (6.40 mm 0.250 in. embedment) in Fig. 2a shallbe used for cords with a dtex of 1100/2 denier larger than1000/2 or less. The dimensions of the mold (9.52 mm 0.375in. embedment) in Fig. 2b shall be used for cords with a dtexlarger t
28、han 1100/2 denier larger than 1000/2. The slot size foreach mold shall be 1.17 mm 6 0.13 mm 0.046 in. 6 0.005in.6.4 Specimen GripsThe design of the specimen gripsshall be as shown in Fig. 3. Two grips are required.6.5 Tensioning MassesThe masses may be of the hooktype, or designed in such a manner t
29、hat they can be clamped tothe cord. In any event, the total mass shall be 50 g.6.6 Sheeted Rubber Compound, (sometimes called skimstock), supported on a non hygroscopic backing, such as aplasticizer-free plastic material. Polyethylene film has beenfound to be satisfactory. The thickness of the rubbe
30、r stockrequired to fill the mold properly shall be determined byexperience.As a guide, the thickness of the rubber stock shouldbe not less than 8 % greater than one-half of the mold cavitydepth. In any event, the thickness is agreed upon between thepurchaser and supplier.6.6.1 Rubber stock propertie
31、s are best maintained by stor-age in a cool, dry atmosphere. Excessive rubber stock moisturemay lower adhesion of some fiber/rubber composites.6.6.2 Rubber compounds exhibit wide variations in shelflife (properties suitable for good adhesion results) dependentupon both composition and storage condit
32、ion. Rubber com-pounds are usually replaced after three months; however, somemay require replacement within a few weeks. In any event,FIG. 1 H-Test SpecimenD4776/D4776M 102storage conditions and shelf life should be specified by thesupplier of the rubber compound.6.7 Timers, having 60 min capacity,1
33、2 min intervals.6.8 Marking Pen, silver ink for rubber.36.9 Shears, for trimming.6.10 Gloves, of temperature resistant material.6.11 Mold Release Lubricant , A suitable mold releaselubricant may be applied to the empty mold to facilitate testblock removal. Excess lubricant shall be wiped from the mo
34、ldand particularly from the slots provided for the cords. Thelubricant should not be applied when exposed cord is in thearea, and should only be used when absolutely necessary. Useof mold release lubricant should be reported on the test report.NOTE 1The use of mold release lubricant is not recommend
35、ed. Themold should be covered permanently with Teflont or, preferably, with astainless stell reinforced nonstick cating such as Excaliburt.7. Sampling7.1 Lot SampleAs a lot sample for acceptance testing,take at random the number of primary sampling units directedin an applicable material specificati
36、on or other agreementbetween the purchaser and the supplier. Consider shippingcases of cord to be the primary sampling units. Exercisecaution in sampling and handling so that samples receiveminimum exposure to ambient atmosphere and light prior torubber embedment. This can be accomplished by storing
37、 thesample in a sealed, black plastic bag. Rayon is particularlysensitive to moisture pick-up (which negatively affects adhe-sion) and should be handled accordingly.NOTE 2A realistic specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybe
38、tween primary shipping units and within primary shipping units so as toprovide a sampling plan with meaningful producers risk, consumers risk,acceptable quality level, and limiting quality level.7.2 Laboratory SampleTake at random the number ofpackages per shipping case in the lot sample directed in
39、 anapplicable material specification or other agreement betweenthe purchaser and the supplier.7.3 Test SpecimensPrepare 15 specimens, or other num-ber as agreed upon between the purchaser and the supplier,from each sample as directed in Section 8.3Available from Fisher Pen Co., Forest Park, IL.NOTE
40、1The mold as shown will produce 30 specimens. It may befabricated to produce a larger or smaller number, but the dimensions thatgovern the specimen size shall not be altered.NOTE 2A mold cover plate must be provided. It should be 9.5 mm.38 in. thick and the same outside dimensions (“K” and“ L” as th
41、e mold.NOTE 3Mold dimension tolerances are XX.X mm 6 .3 mm XX.XXin. 6 .01 in. or XX.XX mm 6 .13 mm XX.XXX in. 6 .005 in.Dimension 2a 2bmm in. mm in.A 12.70 .500 15.88 .625B 17.5 .69 17.5 .69C 6.35 .250 9.52 .375D 3.17 .125 3.17 .125E 34.9 1.38 34.9 1.38F 25.40 1.000 25.40 1.000G 25.4 1.00 25.4 1.00H
42、 1.17 0.046 1.17 0.046J 6.40 .250 6.40 .250K 149.2 5.88 177.8 7.00L 9.5 .38 9.5 .38M 196.8 7.75 196.8 7.75FIG. 2 Mold for H-TestNOTE 1The important dimension is shown by an asterisk and shallnot be altered. All other dimensions are included as guides and may bealtered if desired.Dimension mm in.A 1.
43、6 .06B 12.5 .50C 25.0 1.00D 40.0 1.50E 7.0 .28F 14.0 .56G 4.0 .16FIG. 3 Specimen Grips for H-TestD4776/D4776M 1038. Preparation of Test Specimens8.1 Cut the rubber stock in strips 6 mm 0.25 in. wide and150 mm 6.0 in. long, leaving the protective film attached.This may be done with shears or with a c
44、licker die.8.1.1 Some laboratories have fabricated larger molds toaccommodate a greater number of test specimens. In thoselaboratories, the length of the rubber stock must be adjustedaccordingly.8.2 A mold preheated to the curing temperature is preferred.NOTE 3When a preheated mold is used, the spec
45、imens must be loadedand placed in the curing press within 3 min. The use of a preheated moldwill alter the curing conditions (time and temperature) of the rubber.8.3 Remove the protective film from the rubber test strips,then place the individual rubber test strips in the mold cavitieswith the prote
46、ctive film side on top.8.4 Place the cords in the cord slots by cutting cord testspecimens allowing sufficient overhang for attaching massesand tie a knot in both ends. Take care to prevent the loss of cordtwist. The portion of the cord that is embedded in rubber mustnot be touched by the bare hand.
47、 Attach a 50 g mass on oneknotted end of the test cord. Two cords may be tied togetherand used to fill adjacent slots; a 100 g mass is used in this case(Fig. 4). Place one end of the knotted test specimen so that itis snubbed firmly against the cord slots on one side of the mold.8.5 After all the co
48、rd slots are filled, remove the protectivefilm from the additional strips of rubber and place them in themold cavities on top of the cords. The side from which theprotective film was removed will be down. Identify eachspecimen with a silver ink marking pen.8.6 Place the cover plat on the mold, then
49、remove themasses and place the mold in a preheated press. Adjust thepressure to a minimum of 3.5 MPa 500 psi with reference tothe mold surface. Vulcanize for the specified time at thespecified pressure and temperature. Immediately remove themold assembly from the hot curing press.8.7 Remove mold cover plate then carefully remove theconstructed rubber and cord test pad from the test mold cavityand cool at room temperature. Condition prepared specimens at24 6 1
