Chlorinated Butyl Rubber Compounds

Vulcanization rates are higher than for normal butyl rubber because the presence of allylic halide increases the reactivity of the unsaturated sites. Brominated butyl rubber shows higher vulcanization rates than chlorinated butyl rubber. Halogenated butyl rubbers can be vulcanized with various reagents, e.g. diamines, dihydroxy aromatic compounds and zinc oxide. 

The chloride is used to manufacture silicones, tetramethyl lead and triptane (2,2,3 trimethylbutane). Lesser uses include the manufacture of butyl rubber, higher halogenated methanes, methyl cellulose, quaternary ammonium compounds, methyl mercaptan, methionine, fungicides and pesticides (primarily the Me-arsenate herbicides). Recently the chlorinated fluorocarbons have replaced CH3CI as high volume refrigerants and propellants (ref. 32) Tables 12 and 13 list the chemical and physical properties and potential numbers of workers exposed to the monohalomethanes. 

Methyl chloride is the only chlorinated methane with good growth. The principal use for methyl chloride is in the manufacture of chlorosilanes (89%) for the silicone industry. Other smaller uses are for methyl cellulose ether, quaternary ammonium compounds, herbicides, and butyl rubber. 

FKM vulcanizates have excellent heat resistance, giving continuous service for 1000 hr at 220°C. Useful service is even possible at 250°C. These elastomers are also highly resistant to weathering and ozone attack. FKM vulcanizates are resistant to swelling in hot oils and aliphatic compounds. They also are resistant to aromatics, chlorinated hydrocarbons, and motor fuels. In addition, they are very resistant to most mineral acids. The gas-permeability resistance of FKM vulcanizates even exceeds that of butyl rubber vulcanizates. 

Most compounders use a combination of physical and chemical antiozonants and achieve excellent protection in this way. For more severe ozone-resistance problems, there are, of course, a number of specialty elastomers that are saturated and therefore completely ozone-resistant ethylene/propylene rubber, chlorinated and chlorosulfonated polyethylene, ethylene/vinyl acetate, ethylene/acrylic esters, butyl rubber, SEES, plasticized PVC, butyl acrylate copolymers, polyepichlorohydrin and copolymers, polyetherester block copolymer, polyurethane, and silicone. 

Acrylate styrene acrylonitrile Acrylate modified styrene acrylonitrile Acrylic acid ester rubber Acrylonitrile butadiene rubber or nitrile butadiene rubber Acrylonitrile butadiene styrene Acrylonitrile styrene/chlorinated polyethylene Acrylonitrile methyl methacrylate Acrylonitrile styrene/EPR rubber or, acrylonitrile ethylene propylene styrene Alpha methyl styrene Atactic polypropylene Butadiene rubber or, cis-1,4-polybutadiene rubber or, polybutadiene rubber Butadiene styrene block copolymer Butyl rubber Bulk molding compound Casein formaldehyde Cellulose acetate Cellulose acetate butyrate Cellulose acetate propionate Cellulose nitrate Chlorinated polyethylene Chlorinated polyvinyl chloride Chloro-polyethylene or, chlorinated polyethylene. 

Chlorinated polyethylene (CPE) n. Any polyethylene modified by simple chemical substitution of chlorine on the hnear backbone chain, CPEs range from rubbery amorphous elastomers at 35-40% Cl to hard, semicrystalline materials at 68-75% Cl. They are sometimes included with chlorinated natural and butyl rubbers under the term chlorinated rubbers. Certain CPEs are used as modifiers in PVC compounds to obtain better flexibihty and toughness, particularly low-temperature toughness, greater latitude in compounding, and ease of processing. 

Phenylmercuric borate is 0.08 % soluble in water. Mercury is in this compound covalently bound to the phenyl group. It is incompatible with many anions, including halides. However a 0.004 % solution is compatible with up to 0.7 % sodium chloride. The active concentration is 0.002 %, but a concentration up to 0.004 % may be used to compensate losses by adsorption on the membrane filter, etc. Eye drop bottles with chlorine and bromine butyl rubber droppers cannot be used with phenylmercuric salts, because a precipitate will be formed. An alternative is packaging the eye drops in a bottle with a polypropylene dropper (see Sect. 24.4.2). Phenylmercuric borate causes few hypersensitivity reactions, but with prolonged use, there might be a risk of mercury deposition in the lens. 

Nitrile rubber is used preferably for contact adhesives with improved plasticizer resistance. Polyisobutylene is used in pressure-sensitive adhesives. Butyl rubber is sometimes added to pressure-sensitive and hot-melt adhesives, although it is mainly used in sealing compounds. Epoxy resins and reactive (meth)acrylate adhesives (reactive adhesives) are modified with polychloroprene, butyl, and nitrile rubber. Chlorinated rubber is added in small quantities to contact adhesives and also to rubber-to-metal bonding agents for improving the adhesion properties. 

Resin cures utilise phenol-formaldehyde resins with reactive methylene groups and a small added amount of either a chlorinated rubber, e.g., polychloroprene, or stannous chloride. If halogenated phenolic resins are used the additional source of a halogen may not be required. Resin cures give butyl compounds excellent heat stability and are used to good effect where this is required, e.g., in tyre curing bags which have to resist service at 150 °C in a steam atmosphere. 

Butyl diglycol [112-34-5] [2-(2-butoxyethoxy)ethanol, diethylene glycol monobutyl ether] is a clear, colorless, neutral liquid with a pleasantly mild odor. It is miscible with water and organic solvents, including aliphatic compounds. Butyl diglycol has a high solvency for cellulose nitrate, cellulose ethers, chlorinated rubber, poly(vinyl acetate), polyacrylates, and some oils, as well as for many synthetic resins, natural resins, and dyes. Polystyrene, poly(vinyl chloride), fats, and most oils are not dissolved. 

Butyl Ethylhexyl Phthalate n (butyl octyl phthalate, BOP) A mixed ester of butanol and 2-ethylhexanol, widely used as a primary plasticizer for PVC compounds and plastisols, in which it performs like dioctyl phthalate in most respects. It is also compatible with vinyl chloride-acetate copolymers, cellulose nitrate, ethyl cellulose, polystyrene, chlorinated rubber, and at lower concentrations, with polymethyl methacrylate. 

Cauotchoucs BR-1675 and SEPC-60 in ratio (85 15) compose formula of serial rubbers for diaphragm production, in experimental rubber SEPC-60 was substituted for similar amount of CEPDC-2. It is well known, that chlorine-containing compounds have the ability to activate resin curing of butyl cauotchouc, which is the main elastomer component of membraneous rubbers [1]. 

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