Tire cords properties

The major load-bearing member of cord—mbber composites is the cord, which provides strength and many other critical properties essential for tire performance. Cords in pHes form the stmctural backbone of the tire. The mbber plays the important but secondary role of transmitting load to the cords via shearing stresses at the cord—mbber interface. Other expected performance characteristics of the tire are due to design and manufacturing processes. Table 5 (96) identifies several tire performance characteristics and how they are dependent on tire cord properties. 

Introduced successfully for tires in 1967, glass fibers had properties that made them very attractive for use in tires (5,8). The britdeness of glass fibers, however, imposed some limitations on the final tire cord properties because of the requirement that each fiber be individually coated with a rubbery adhesive to avoid interfilament damage during fabrication and use. This additional treatment step is introduced at the fiber manufacturing stage. For several years fiber glass was used extensively in bias-belted and radial tires, but was ultimately replaced by steel belts in radial tires. 

Some amino resins are used as additives to modify the properties of other materials. For example, a small amount of amino resin added to textile fabric imparts the familiar wash-and-wear quaUties to shirts and dresses. Automobile tires are strengthened by amino resins which improve the adhesion of mbber to tire cord (qv). A racing sailboat may have a better chance to win because the sails of Dacron polyester have been treated with an amino resin (1). Amino resins can improve the strength of paper even when it is wet. Molding compounds based on amino resins are used for parts of electrical devices, botde and jar caps, molded plastic dinnerware, and buttons. 

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). 

Tire compounds, aged and fatigued properties of, 21 811-812 Tire cord, 2 643-644 Tire-derived fuel (TDF), 21 463—464 industrial uses for, 21 465 use in electrical generation, 21 465 use in pulp and paper mills, 21 464 Tire pulverizing, cryogenic, 21 469-470 Tire retreading, 21 479 Tires... 

Whenever a new high strength fiber is developed, its potential for tire cord use is always explored because of the commercial attraction of large volumes available in the tire market. Few materials have emeiged to displace the current two major fibers, nylon and polyester (14). Nonetheless, many examples of fibers offering attractive properties for tire cords have been reported in the literature, eg, polyethylene ketone (17), poly(paraphenylene benzobisoxazole) (18), acrylics (19), and high strength poly (vinyl alcohol) (20) (see Vinyl polymers). 

The high-modulus tire cords within waste rubber have desirable strength retention properties under long-term exposure to aggressive environment. Properties of this tire threads were shown in table 3. 

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