Carcass tire applications

Ground mbber has replaced reclaim in many tire applications including treads, carcasses, innerliners, subtreads, and bead components. It is also used in mechanical goods, footwear, solid tires, mats, and retreads. Cryogenically and wet-ground mbbers which are of smaller particle size can be used at moderately bigb levels and still allow compounds to be processible. 

The performance properties of PEN present opportunities for replacement of rayon or polyamide in carcass construction. The use of PEN cord in these applications is currently being evaluated in both Asia and Europe. PEN has demonstrated acceptable flexural fatigue equivalent to polyethylene terephthalate (PET) and rayon. It has equivalent toughness to rayon, which is important for sidewall impact resistance. PEN s superior mechanical properties also afford opportunities to use less fiber in carcass construction enabling production of lighter-weight, more fuel-efficient tires. 

Firestone and Shell started commercial production of cis-polyisoprene by the anionic process in the 1950 s but these plants are no longer in operation now. About the same time, Phillips started the manufacture of polybutadienes by the anionic route and ever since, there has been a steady growth in their use, particularly in the tire-tread as well as tire-carcass formulations. These solution polybutadienes, generally, have low vinyl contents but recently, Phillips has found some interesting applications for medium vinyl polybutadienes as well.14 Polybutadienes with 50-55 percent vinyl contents behave like emulsion polymerized SBR in tire tread formulations and exhibit very similar tread... 

In the category of industrial applications, nylon is the predominant fiber used in the carcass of bias truck, racing car, and airplane tires because of its excellent strength, adhesion to mbber, and fatigue resistance. Nylon is used less in the carcass of radial tires for automobiles and in replacement bias and bias-belted tires because of the development of temporary fiat spots. For this reason, nylon has lost most of this market to polyester. 

Protects against thermo-oxidative degradation in natural and synthetic rubbers as well as plastics. It is commonly used in applications such as tire carcasses, wire breaker retreads, apex, belts, hoses, seals, mechanical goods, footwear and wire. 

Polyisoprene rubbers are used in the construction of automobile tire carcasses and inner liners and truck and bus tire treads. Other important applications are in mechanical goods, sporting goods, footwear, sealants, and caulking compounds. 

There are certain technical limitations in the devulcanization of rubbers, and vulcanization is, in fact, not truly reversible (Pryweller, 1999). The partial devulcanization of scrap rubber will result in a degradation of physical properties. In many cases, this may limit the amount of substitution levels in high-tech applications such as passenger tires. But it can provide the compounder of less stringent products with an excellent low-cost rubber that can be used as the prime rubber or at very high substitution levels. According to Franta (1989), reclaim cannot be used for tread compounds in tires because every addition may decrease their resistance to wear. However, this statement has not been checked in case rubber devulcanized without an addition of chemicals. Considerable amounts of reclaim are consumed for carcasses of bias ply tires for cars if the compounds are of NR for carcasses of radial tires no reclaim is added. On the other hand, reclaim is added to compounds for bead wires and it may also be added to sidewalls. Within the framework of direct recycling options a number of applications for GRT outside the rubber industry have been proposed. Such applications include the use as a tiller in asphalt for the surface treatment of roads and as a rubberized surface for sport facilities. 

MAJOR APPLICATIONS Tire treads, carcass, belts, hoses, gaskets, seals, and protective coatings component in other synthetic rubbers and blends. 

The uncured rubber stock is passed through a series of gaps of decreasing size made by a stand of rotating rolls, and the final roll gap determines the sheet thickness (Fig. 4.31). A variant of this is the use of a calendering process for the production of coated fabric for such applications as carcass plies in tires (Fig. 4.32). 

The applications are primarily tire tread and carcass stock, conveyor belt coverings, V-belts, hose covers, tubing, golf balls, shoe soles and heels, sponges, and mechanical goods. ... 

The most important commercial use of elastomer blends is in the huge tire market. These blends are generally phase separated and represent one of the largest single applications for immiscible or miscible blends. Ckjmpatibilization is achieved via crosslinking reactions across the interface. The use of SBR/PB (polybutadiene) and NR(natural rubber)/PB for tread, NR/SBR/PB and NR/PB for carcass, NR/PB and NR/SBR for sidewall and NR/SBR/PIB... 

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