1、Designation: D4776/D4776M 10D4776/D4776M 18Standard 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 origina
2、l adoption or, 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 of reinforcing
3、 cords that are bonded to rubber compounds. This testmethod is applicable to textile cord structures from both natural and manmade fibers, other than steel. For adhesion testing of steeltire cords, refer to Test Method D2229.1.2 This test method is primarily used to evaluate tire cords, using a suit
4、able 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 oneconsistent form of tire cord and one consistent rubber compound. This test method may be used to evaluate cords in i
5、ndustrial hoseand belting products and other cord reinforced rubber products.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the
6、 other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health,
7、 and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of Internati
8、onal Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1566 Terminology Relating to Rubber
9、D2229 Test Method for Adhesion Between Steel Tire Cords and RubberD4393 Test Method for Strap Peel Adhesion of Reinforcing Cords or Fabrics to Rubber CompoundsD6477 Terminology Relating to Tire Cord, Bead Wire, Hose Reinforcing Wire, and Fabrics3. Terminology3.1 Definitions:3.1.1 For defintionsdefin
10、itions of terms relating to tire cord, bead wire, hose wire, and tire cord fabrics, refer to TerminologyD6477.3.1.1.1 The following terms are relevant to this standard: adhesion, adhesion, in tire fabrics, cord, curing, H-test adhesion,industrial yarn, reinforcing cord, rubber, rubber compound, as u
11、sed in the manufacture of rubber articles, vulcanization.3.1.2 For definitions of other terms relating to rubber, refer to Terminology D1566.3.1.3 For definitions of other textile terms related to textiles, refer to Terminology D123.1 This test method is under the jurisdiction ofASTM Committee D13 o
12、n Textiles and is the direct responsibility of Subcommittee D13.19 on Industrial Fibers and MetallicReinforcementsCurrent edition approved Jan. 1, 2010Jan. 1, 2018. Published January 2010February 2018. Originally approved in 1988. Last previous edition approved in 20042010 asD4776 04D4776 10. 1. DOI
13、: 10.1520/D4776-10.10.1520/D4776-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an A
14、STM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In
15、all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A cord specimen is sandwiched between two la
16、yers of rubber compound test stock in a form resembling an “H,” placed ina heated mold, and cured at a specified temperature and pressure. The test specimen sandwich is then cut to create an H-testspecimen consisting of a single cord with each end embedded in the center of a tab end of the rubber te
17、st block (Fig. 1). The testspecimen is placed in the grips of the tensile tester, and then the grips are separated. The maximum force obtained is the H-testadhesion force.5. Significance and Use5.1 Test Method D4776 for the determination of the H-test adhesion of reinforcing cords to rubber compound
18、s may be used forthe acceptance testing of commercial shipments of reinforcing cords but caution is advised since information aboutbetween-laboratory precision is incomplete. Comparative tests as directed in 5.1.1 may be advisable.5.1.1 In cases of dispute arising from the differences in reported te
19、st results when using Test Method D4776 for acceptancetesting of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is statisticalbias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. A
20、s a minimum, thetwo parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material ofthe type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. Theaverage results from the two lab
21、oratories should be compared using Students t-test for unpaired data and an acceptable probabilitylevel chosen by the two parties before testing begins. If a bias is found, either its cause must be found and corrected or the purchaserand the supplier must agree to interpret future test results in li
22、ght of the known bias.5.2 This test method is used to measure the force required to extract the cord from a rubber compound test block.5.3 This test method is designed to test the adhesion of textiles that are bonded to rubber compounds. Variables that maycontribute to differences in results of this
23、 test method include adhesive type, adhesive application procedure, adhesive cure, fibertype, construction of cords, rubber type, rubber cure, and rubber thickness.5.3.1 The deleterious effect of ozone in combination with atmospheric moisture on the ability of adhesives to bond with rubberrequires a
24、ssiduous protection of cords prior to embedment.FIG. 1 H-Test SpecimenD4776/D4776M 1825.4 The expected range of values which characterize acceptable adhesion can be determined in any cord-rubber combinationwith experience. For this reason, the purchaser normally establishes a minimum level of adhesi
25、on to be obtained by the supplierin either the suppliers laboratory or the purchasers laboratory using either the suppliers standard rubber compound or thepurchasers rubber compound.5.5 Another procedure for testing adhesion of cords to rubber compounds isTest Methods D4393 .This procedure has been
26、usedextensively in the trade for acceptance testing. Results obtained by this method cannot be used interchangeably since there is nooverall correlation between them.6. Apparatus and Materials6.1 Tensile Testing MachineAlthough a constant-rate-of-extension (CRE) tensile testing machine is preferred,
27、 a constant-rate-of-traverse (CRT type, pendulum type) may be used. The specification and methods of calibration and verification of thesemachines shall conform to Specification D76. The testing machine shall be equipped with an autographic recorder (rectilinearcoordinates preferred) or an interface
28、 computer. There is a distinct difference between the CRE and CRT type testing machines.Consequently, they cannot be used interchangeably unless a mathematical correlation has been established and agreed upon by thepurchaser and supplier.6.2 Curing Press, capable of maintaining a minimum pressure of
29、 3.5 MPa 500 psi over the total area of the mold surface,equipped with 300 by 300 mm 12 by 12 in. platens or larger, and capable of a platen temperature control within 63C 65Fof the temperature specified for curing the rubber compound.6.3 MoldsThe design of the molds shall be as shown in Fig. 2. The
30、 dimensions of the test specimen are controlled by thespecifications and tolerances of the mold. The dimensions of the mold (6.40 mm 0.250 in. embedment) in Fig. 2a shall be usedfor cords with a dtex of 1100/2 denier larger than 1000/2 or less. The dimensions of the mold (9.52 mm 0.375 in. embedment
31、)in Fig. 2b shall be used for cords with a dtex larger than 1100/2 denier larger than 1000/2. The slot size for each mold shall be1.17 mm 6 0.13 mm 0.046 in. 6 0.005 in.6.4 Specimen GripsThe design of the specimen grips shall be as shown in Fig. 3. Two grips are required.6.5 Tensioning MassesThe mas
32、ses may be of the hook type, or designed in such a manner that they can be clamped to thecord. In any event, the total mass shall be 50 g.6.6 Sheeted Rubber Compound, (sometimes called skim stock), supported on a non hygroscopic non-hygroscopic backing, suchas a plasticizer-free plastic material. Po
33、lyethylene film has been found to be satisfactory. The thickness of the rubber stock requiredto fill the mold properly shall be determined by experience. As a guide, the thickness of the rubber stock should be not less than8 % greater than one-half of the mold cavity depth. In any event, the thickne
34、ss is agreed upon between the purchaser and supplier.NOTE 1The important dimension is shown by an asterisk and shall not be altered. All other dimensions are included as guides and may be alteredif desired.Dimension mm in.A 1.6 .06B 12.5 .50C 25.0 1.00D 40.0 1.50E 7.0 .28F 14.0 .56G 4.0 .16FIG. 3 Sp
35、ecimen Grips for H-TestD4776/D4776M 1836.6.1 Rubber stock properties are best maintained by storage in a cool, dry atmosphere. Excessive rubber stock moisture maylower adhesion of some fiber/rubber composites.6.6.2 Rubber compounds exhibit wide variations in shelf life (properties suitable for good
36、adhesion results) dependent uponboth composition and storage condition. Rubber compounds are usually replaced after three months; however, some may requirereplacement within a few weeks. In any event, storage conditions and shelf life should be specified by the supplier of the rubbercompound.6.7 Tim
37、ers, having 60 min capacity, 12 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 release lubricant may be applied to the empty mold to facilitate test blockremoval. Excess lubri
38、cant shall be wiped from the mold and particularly from the slots provided for the cords. The lubricant shouldnot be applied when exposed cord is in the area, and should only be used when absolutely necessary. Use of mold release lubricantshould be reported on the test report.3 Available from Fisher
39、 Pen Co., Forest Park, IL.NOTE 1The mold as shown will produce 30 specimens. It may be fabricated to produce a larger or smaller number, but the dimensions that governthe 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 outs
40、ide dimensions (“K” and“ L” as the mold.NOTE 3Mold dimension tolerances are XX.X mm 6 .3 mm XX.XX in. 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
41、 25.40 1.000G 25.4 1.00 25.4 1.00H 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-TestD4776/D4776M 184NOTE 1The use of mold release lubricant is not recommended. The mold should be covered permanently with Teflon or, prefera
42、bly, with a stainlessstell reinforced nonstick cating such as Excalibur.7. Sampling7.1 Lot SampleAs a lot sample for acceptance testing, take at random the number of primary sampling units directed in anapplicable material specification or other agreement between the purchaser and the supplier. Cons
43、ider shipping cases of cord tobe the primary sampling units. Exercise caution in sampling and handling so that samples receive minimum exposure to ambientatmosphere and light prior to rubber embedment. This can be accomplished by storing the sample in a sealed, black plastic bag.Rayon is particularl
44、y sensitive to moisture pick-up (which negatively affects adhesion) and should be handled accordingly.NOTE 2A realistic specification or other agreement between the purchaser and the supplier requires taking into account the variability betweenprimary shipping units and within primary shipping units
45、 so as to provide a sampling plan with meaningful producers risk, consumers risk, acceptablequality level, and limiting quality level.7.2 Laboratory SampleTake at random the number of packages per shipping case in the lot sample directed in an applicablematerial specification or other agreement betw
46、een the purchaser and the supplier.7.3 Test SpecimensPrepare 15 specimens, or other number as agreed upon between the purchaser and the supplier, from eachsample as directed in Section 8.8. Preparation of Test Specimens8.1 Cut the rubber stock in strips 6 mm 0.25 in. wide and 150 mm 6.0 in. long, le
47、aving the protective film attached. Thismay be done with shears or with a clicker die.8.1.1 Some laboratories have fabricated larger molds to accommodate a greater number of test specimens. In those laboratories,the length of the rubber stock must be adjusted accordingly.8.2 A mold preheated to the
48、curing temperature is preferred.NOTE 3When a preheated mold is used, the specimens must be loaded and placed in the curing press within 3 min. The use of a preheated mold willalter the curing conditions (time and temperature) of the rubber.8.3 Remove the protective film from the rubber test strips,
49、then place the individual rubber test strips in the mold cavities withthe protective film side on top.8.4 Place the cords in the cord slots by cutting cord test specimens allowing sufficient overhang for attaching masses and tiea 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 betouched by the bare hand. Attach a 50 g mass on one knotted end of the test cord. Two cords may be ti
