Curing bladders

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). 

Resin Cure. Resin cure systems yield carbon—carbon cross-links and, consequendy, thermally stable materials. Butyl mbber vulcanised with resins are used as tire-curing bladders, and have a life of 300—700 curing cycles at steam temperature of 175°C at about 20 m/cycle. 

The main applications of butyl rubber are in wire and cable applications, inner tubes, inner liners in tubeless tyres, tyre curing bladders, and pharmaceutical closures, the latter utilising the low... 

The compounded rubber stock will be further processed for use. The process could be injection or transfer molding into a hot mold where it is cured. Tire curing bladders are made in this fashion. Extrusion of the rubber stock is used to make hose or tire treads and sidewalls. Another common process is calendaring, in which a fabric is passed through rolls where rubber is squeezed into the fabric to make fabric-reinforced rubber sheets for roofing membranes or body plies for tires. The actual construction of the final product can be quite complex. For example, a tire contains many different rubber components some of which are cord or fabric reinforced. All of... 

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... 

Major polymer applications belting, steam hose, curing bladders, O-rings, shock and vibration products, structural caulks and sealants, water-barrier applications, roof coatings, and gas-metering diaphragms... 

Building on technologies first developed in Germany in the early 1930s, Robert M. Thomas and William J. Sparks, both employees of Standard Oil (now ExxonMobil Chemical), patented a new synthetic rubber in 1937. Butyl rubber is characterized by a very saturated linear polymer chain, leaving little space between molecules for transmission of air, vapors, moisture, or water. As such, butyl rubber was successfully used during World War II as a substitute for natural rubber in the manufacture of tire inner tubes and curing bladders. 

Uses Rubber for use in tire inner tubes/liners/curing bladders, pharmaceutical closures, mech. goods, conveyor belts/hosing antivibration mounts food/drug seals adhesives in closure-sealing gaskets for food containers in food-contact articles for repeated use... 

Rodgers, B., Jacob, S., Curry, C., and Sharma, B.B. (2009) Butyl rubber curing bladder resin vulcanization systems compositions and optimization. Paper 107. Presented at a Meeting of the American Chemical Sodely Rubber Division, Pittsbmgh PA. 

Butyl rubber is used to make innertubes and curing bladders (see Butyl Rubber). Butyl polymers are about eight times more resistant to air permeability compared to natural rubber and have excellent resistance to heat, steam, and water. This accounts for its use in gaskets and diaphragms for hot water and steam services. In addition, butyl rubber can be compoimded to have low resilience properties and has found use in high damping mounts for engines, motors, and similar devices (6,17,18). 

Applications conveyor belts, curing bladders, hoses, membranes, pharmaceutical stoppers, seals, tank liners, tire innerlines, tire non-staining sidewalls ... 

Star-branched butyl rubber is used for inner tubes, nonstaining sidewaUs, coverstrips for white sidewaUs, body mounts, and curing bladders. Duradene solution-SBR grades... 

TABLE 18 Curing bladder recipe based on butyl rubber ... 

Acetylene carbon black is derived from the pyrolysis (thermal decomposition) of acetylene gas. The production volumes of acetylene black are extremely low compared to the billions of pounds of furnace blacks produced annually. Acetylene blacks are basically used where special compounding applications are needed, such as improved thermal conductivity. One of the larger areas of use is in the production of tire-curing bladders (because of the need for better thermal conductivity). 

Generally, the remaining 10% of ruhher compounds have cure systems based mostly on peroxide curatives. However, a small number of compounds based on halogen-ated elastomers (such as polychloroprene) have cure systems based on metal oxides. Also, resin cures are used in special cases to cure some compounds such as curing bladders for tires. 

PF curing resin is used with hutyl compounds to impart excellent heat resistance. Thus butyl-ruhher-based compounds with these curing resins can be used to make curing bladders that can withstand many repeated heats in curing tires. 

TYPICAL FORMULATIONS Tire curing bladder lubricant ... 

Sulphur curing systems provide long service in air at 100°C or less quinoid systems give vulcanisates with greater stability than sulphur systems and are suitable for short-term or intermittent service in air at temperatures up to ISO C extended service in air at 150-200 °C demands resin cures. Tyre curing bladders, for example, are virtually always made from resin cured butyl rubber. However, at high temperatures in the absence of air, e.g. in super heated, deaerated steam, properly cured butyl rubbers perform exceptionally well, irrespective of curing system. 

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