Tire cord adhesion test

Both static and dynamic tests are employed to evaluate the adhesion strength of cord-mbber composites. The major static tests used in tire industry are H-adhesion, 90/180° peel test, tire cord adhesion test (TCAT) and co-axial shear pull-out test (CSPT). Although these methods are... 

FIGURE 12.20 Tire cord adhesion test specimens and scan area of fracture surfaces. (From Chandra, A.K., Mukhopadhyay, R., and Bhowmick, A.K., Polym. Test., 15, 13, 1996. With permission.)... 

Pullout Tests. The method to determine the adhesion between the dipped cords and the SBR vulcanizate was the tire cord adhesion test (L/,75), Figure 1. Here, two cords are embedded (to a depth of 10 mm) into opposite ends of a rubber block (76 mm x 13 mm x 6.4 mm). Samples are then cured 23 min at 155 °C and allowed to rest 1 day. Bond strengths are determined by clamping the two free cord ends in an Instron and pulling at the rate of 50 mm/min. 

One of the main points of debate w ith the above methods is the stress distribution due to gripping the rubber block. Nicholson ct al. [41.42] used a test with two cords embedded in the block of rubber and avoided holding the block in one grip of the testing machine. Further analysis was made by Brodsky [43], who used three cords. Ellul and Emerson [44.45] used cords embedded in steel enclosed rubber cylinders with alternatively hot and cold bonding. Ridha et al. [46] have calculated the stress fields in tire cord adhesion test pieces, and Mollet [47] has compared the various methods. 

Ellul, M.D. and Emerson, R.J. (1988a). A new pull-out test for tire cord adhesion-Part I, Hot bonding. Rubber Chem. Technol. 61, 293-308. 

McCarvill and Bell ° have described the use of torsional test for the determination of adhesive joint strength, and dynamic loss has been used to measure tire cord adhesion to rubber. Holographic method has been suggested as one non-destructive method for... 

Although this paper does not deal with the tire cord adhesives, the use of the steel belt in the newer radial tires and in truck tires has Indicated a need for better adhesive systems and methods of testing the steel cord to rubber adhesion. ... 

Wire cords are particularly subject to degradation of their adhesion values by moisture. To combat this, halogenated butyl (HIIR) is used in tire innerliners because of its property of low air and water vapor diffusion rates. Moisture is present in most air pumps and many tires are mounted with water left in the tire on mounting. For these reasons tires and tire compounds are tested extensively at simulated aging conditions in the laboratory and on test vehicles before they are sold to the customer. 

Tire cords are characterized for their physical, adhesion, and fatigue properties for use in tires. These characterizations are conducted under normal and varying test conditions to predict their performance during tire operation. Various test methods used to characterize tire cords are described. 

Standard Test Method for Adhesion Between Steel Tire Cords and Rubber. Steel cords are vulcanised into a block of mbber and the force necessary to pull the cords linearly out of the mbber is measured as adhesive force. ASTM method D2229-93a can be used for evaluating mbber compound performance with respect to adhesion to steel cord. The property measured by this test method indicates whether the adhesion of the steel cord to the mbber is greater than the cohesion of the mbber, ie, complete mbber coverage of the steel cord or less than the cohesion of mbber (lack of mbber coverage). 

ASTM D4776, 2004. 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, 2002. 

The adhesion of textile or metal cord to polymers is essentially restricted to rubbers used in tires and to some extent in belting. The basic form of static test consists of measuring the force to pull a cord out of a block of rubber into which it has been vulcanized, and it is apparent that the result is critically dependent on the efficiency with which the test piece was molded. The measured force is also dependent on the amount that the rubber deforms during the test. 

Adhesion is represented by the force required to pull an embedded cord through and out of a rubber block in the H-Test, T-Test, and U-Test. " In these methods, the force is affected by the embedded length of the cord, the rate of loading, and the temperature of the test sample. Measurements are frequently made at 100-130°C, since temperature in a running tire may be this high. Fig. 4 illustrates these pull-out tests. 

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