Tire inner liners

Tire industry Tire inner liners Tire molds Tire reinforcement Tire-reinforcement fib(... 

PIB and various copolymers are called butyl rubber. Butyl rubbers have lower permeability and higher damping than other elastomers making them ideal materials for tire inner liners and engine mounts. 

Nanocomposites are being used in tires, in particular, tire inner liners. Here, less permeable inner layers are achieved by the introduction of clad layers, which allow the use of a thinner inner liner, resulting in an overall lighter tire. Tire inner layers are typically derived from butyl rubber, often halogenated butyl rubber. 

Another approach utilizes highly oriented pyrolytic graphite that is separated into individual graphite sheets as the inner layer material. In each case, the nano-clay or graphite material is present in about 2% by weight in the tire inner liner. 

The most important characteristics of butyl rubber are its low permeability to air and its thermal stability. These properties account for its major uses in inner tubes, tire inner liners, and tire curing bladders. Because of the poor compatibility of butyl with other rubbers (with respect to both solubility and cure), the halobutyls are preferred. The brominated p-methylstyrene-containing butyl rubbers are used in a number of grafting reactions for tire applications and adhesives. Other uses for butyl rubber are automotive mechanical parts (due to the high damping characteristics of butyl), mastics, and sealants.55... 

BromobntyL OBxxon] Brominatedisobu-tylene-isopiene elastomer, for tire inner liners and pharmaceutical stoppers fast curing. 

Butex. [Midwest Rubber Reclaiming] Reclaimed rubber from butyl inner tubes used in tire inner liners, inner tubes, butyl tapes and sealants. 

Chlorobutyl. [Exxon] Chlorinated isobu-tylene-isoprene rubber used fcx tire inner liners, sidewalls, pharmaceutical stoppers. 

Polysar. [Polysar] Isobuq lene/isoprene copolymers, ETOM, or EPM rubbers rubber for use in tire inner liners, pharmaceutical closures, medianical goods, gaskets, seals, hose, premies, insulation, chewing gum base, tank linings, sponge adhesives, set ts. 

Critical to a tire s hfe cycle performance is the ability to maintain air pressure. Tire inner liners 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 20 High performance tire inner liner compoxmd based on bromobutyl rubber... 

T. Maruyama, K. Ishikawa, N. Amino, and M. Ikawa. Organically modified layered clay as well as organic polymer composition and tire inner liner containing same, US patent. 6908958 B2, 2005. 

The most important characteristic of butyl rubber is its low permeability to air. This property accounts for its major use in inner tubes and tire inner liners. Because of the poor compatibility of butyl with other rubbers (with respect to both solubility and cure), the halobutyls are preferred. 

The alkyl phenol disulfides are mainly used in tire inner liners for heat resistance, along with a conventional accelerator system. The R group is f-butyl or amyl. In addition to donating sulfur for cross-linking purposes, these materials can also function as bisphenolic curatives (see Section 13.6). 

Butyl ruhher vulcanizates have tensile strengths up to 2,000 psi, and are characterized hy low permeahility to air and a high resistance to many chemicals and to oxidation. These properties make it a suitable rubber for the production of tire inner tubes and inner liners of tubeless tires. The major use of butyl rubber is for inner tubes. Other uses include wire and cable insulation, steam hoses, mechanical goods, and adhesives. Chlorinated butyl is a low molecular weight polymer used as an adhesive and a sealant. 

The inner liner forms the vital internal membrane which holds the inflation medium at an elevated pressure within the structure of the tire. In early days the liner was a separate tube of natural or butyl, or more particularly, XIIR compound as an integral part of the tire structure. Adhesion levels of butyl compounds can be critically low requiring an insulating or barrier layer of an NR compound to act as an interface between the liner and the casing. 

Polyisoprene rubbers are used in the construction of passenger, truck, and bus tires and inner liners, as well as sealants and caulking compounds, sporting goods, gaskets, hoses, rubber sheeting, gloves, belts, and footwear. 

As the inner liner is processed, the sheets align forming a clad that reduces the ability of air to flow from the tire. 

BR is used in nearly all parts of the tire with the exception of the inner liner it is always blended with natural rubber (NR) or styrene-butadiene rubber (SBR). Apart from the extrudability, in NR blends the Nd-BR polymers exhibit advantages in all important compound and vulcanizate properties. Also, in SBR blends Nd-BR leads to the best vulcanizate properties in comparison with all other types of BR. 

Inner liner formulated to ensure retention of compressed air in tubeless tire, good air retention, moisture impermeabihty, flex fatigue resistance, durability... 

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