Innerliner

Quinone dioximes, alkylphenol disulfides, and phenol—formaldehyde reaction products are used to cross-link halobutyl mbbers. In some cases, nonhalogenated butyl mbber can be cross-linked by these materials if there is some other source of halogen in the formulation. Alkylphenol disulfides are used in halobutyl innerliners for tires. Methylol phenol—formaldehyde resins are used for heat resistance in tire curing bladders. Bisphenols, accelerated by phosphonium salts, are used to cross-link fluorocarbon mbbers. 

Butyl and Halobutyl Rubber. Butyl mbber is made by the polymerization of isobutylene a small amount of isoprene is added to provide sites for curing. It is designated HR because of these monomers. Halogenation of butyl mbber with bromine or chlorine increases the reaction rate for vulcanization and laminates or blends of halobutyl are feasible for production of mbber goods. It is estimated that of the - 100 million kg of butyl (UR) and halobutyl (HIIR) mbber in North America, over 90% is used in tire apphcations. The halogenated polymer is used in the innerliner of tubeless tires. Butyl mbber is used to make innertubes and curing bladders. The two major suppHers of butyl and halobutyl polymers in North America are Exxon and Bayer (see ELASTOLffiRS,SYNTHETIC-BUTYLrubber). 

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. 

A typical automobile tyre consists of several parts (Fig. 5). The tread and sidewall make up the outside of the tyre. The tread is the portion of the tyre that comes into contact with the road, whereas the sidewall, or wall, is the side of the tyre that connects the tread and the bead. The tread is reinforced from underneath by the belt, which comprises a set of fabrics and/or wires. The plies, found in association with the belt, are layers of rubber-coated cords, which are typically made of fabric, polymer, fibreglass, or steel. The set of belts and plies is often collectively referred to as the cord, or cord body, of the tyre. The cords of the tyre wrap around the bead, the part of the tyre that rests on the tyre rim. The bead consists of both mbber bead filler and a series of steel bead wires. The last major part of the tyre, the innerliner, is a low-permeability... 

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 sidewall compound is compounded to protect the ply and must possess resistance to weathering, ozone, abrasion, and tearing while providing excellent flex fatigue resistance. The innerliner compound must provide good air-permeation resistance and resist moist/hot air aging. The inside of a hot... 

Halogenation of the isoprenyl unit provides enhanced cure reactivity to the rubber molecule, increases the covulcanizability and adhesion to unsaturated tire elastomers, and opens the field of tubeless tire innerliners. 

Halobutyls, which can easily covulcanize with high-unsaturation rubbers, are used in innerliners for tubeless tires as component for sidewalls of passenger-car tires and for heat-resistant truck inner tubes. Other applications involve a variety of sealant tapes, caulks, and pharmaceutical closures. 

Halobutyl rubber (HIIR) is used primarily in tire innerliner and white sidewalls. These elastomers are best for tire air retention owing to lower air permeability as well as aging and fatigue resistance. The chlorinated (CIIR)... 

Critical to a tire s life cycle performance is the ability to maintain air pressure. Tire innerliners composed of halobutyl-based compounds exhibit very low air and moisture permeability. Therefore, tires built with the proper selection of compounds can reduce the rate of premature failure, again delaying entry into the scrap tire and solid waste streams. 

Table 9.36 illustrates how the incorrect selection of a tire innerliner polymer will lead to more rapid deterioration in tire performance properties. Replacement of chlorobutyl with natural mbber or reclaimed butyl will lead to a more rapid loss in tire air pressure and loss in overall tire performance (Niziolek, 2000). 

The tire is a complicated composite product consisting of tread, undertread, carcass, innerliner, bead, and sidewall. Many different types of rubber and carbon black reinforcement are used in manufacturing tires. Therefore, GRT is a blend of various rubbers and carbon blacks. Accordingly, in using GRT powder and devulcanized GRT in new tire manufacturing, many factors should be considered. Evidently, scrap tire powder can be used as a filler for virgin rubbers and devulcanized GRT can be used in blends with virgin rubbers. This market consumed approximately 1.354 x 10 tons of scrap tire rabber in 2009 (US Scrap Tire Markets, 2009). 

Bromobutyl rabber is relatively impermeable to air and moisture and it is often a major portion of the tire innerliner composition. The addition of the starch/plasticizer dispersion composite further reduces the already low air permeability of the butyl rubber-based com-positioa Starches with high softening points are difficult to incorporate it into rabber composition without plasticizer. ... 

Automotive Door Innerliners, Utility Camper Hardtops and Doors Shelves Motorcycle Windshields, Shrouds,... 

Buttons and bows -Zipper -Innerliner Sewing machine lubricating oils... 

Now dynamically vulcanized rubber-plastic blends are poised to enter the realm of automobile tires. A TPV comprising a PA thermoplastic phase with isobutylene-co-p-methylstyrene (BIMSM) rubber can be used as an innerliner, outperforming either historical butyl rubber or the more classical halobutyl and its blend with natural rubber. These and future developments are targeting down-gauging of the barrier film thickness to simultaneously reduce both tire weight and reduced air permeation. A five-to-tenfold reduction in the latter is claimed to be feasible along with improved tire performance (Tsou 2007). 

Table 4.11 Model formulations for an automobile tire innerliner and summary of properties. . ...

Halogenated butyl rubber greatly extended the usefulness of butyl rubber by providing much higher vulcanization rates and improving the compatibility with highly unsaturated elastomers, such as natural rubber and styrene-butadiene rubber (SBR). These properties permitted the production of tubeless tires with chlorinated or brominated butyl innerliners. The retention of air pressure (5) and low intercarcass pressure (6) extended tire durability. 

N650 High modulus, high hardness, low die swell, smooth extrusion Tire innerliners, carcass, belt, sidewall compounds, seals, friction compounds, sheeting... 

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