Chlorinated isobutylene isoprene rubber

CIIR Chlorinated isobutylene-isoprene rubber (chlorobutyl rubber)... 

ACRONYMS PIB, HR (isobutylene isoprene rubber), ClIIR (chlorinated HR), BrIIR (brominated IIR) ... 

Chlorobutyl rubber is chlorinated isobutylene-isoprene. It has the same general properties as butyl rubber but with slightly higher allowable operating temperatures. 

Synonyms Butyl rubber, chlorinated Chlorinated butyl rubber Chlorinated isobutylene/isoprene copolymer Chlorobutyl rubber CNR... 

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) and brominated (BUR) versions of isobutylene isoprene rubber (HR) can be blended with other elastomers to improve adhesion between HIIR compounds and those based on general purpose elastomers, and improve vulcanization kinetics [16]. 

Butyl rubber (HR) contains isobutylene as the parent material to which small proportions of butadiene or isoprene are added. Commercial butyl rubber may contain 5% butadiene as a copolymer. Chlorobutyl rubber (CIIR) is chlorinated isobutylene-isoprene. Both rubbers have the same general properties except that chlorobutyl rubber has a slightly higher allowable operating temperature. 

Establishments primarily engaged in manufacturing synthetic rubber by polymerization or copolymerization. An elastomer for the purpose of this classification is a rubber-like material capable of vulcanization, such as copolymers of butadiene and styrene, or butadiene and acrylonitrile, polybutadienes, chloroprene rubbers, and isobutylene-isoprene copolymers. Butadiene copolymers containing less than 50 percent butadiene are classified in Industry 2821. Natural chlorinated rubbers and cyclized rubbers are considered as semifinished products and are classified in Industry 3069. 

Butyl rubber, brominated. See Isobutylene/isoprene copolymer, brominated Butyl rubber, chlorinated. See Isobutylene/isoprene copolymer, chlorinated Butyl salicylate... 

Chlorinated butyl rubber. See Isobutylene/isoprene copolymer, chlorinated Chlorinated dioctyl terephthalate. See Dioctyl terephthalate chlorinated Chlorinated hydrochloric ether. See 1,1-Dichloroethane... 

Polysar 3350-, Polysar 4220, Polysar 4300. See Polystyrene, high-impact Polysar Butyl 100-3 Polysar Butyl 302 Polysar Butyl XL-20, Polysar Butyl XL-10,00, Polysar Butyl XL 30102 Polysar Butyl XL 40302 Polysar Butyl XL 41106 Polysar Butyl XL 54006 Polysar Butyl XL 68102. See Isobutylene/isoprene copolymer Polysar Chlorobutyl 1240-Pharma. See Isobutylene/isoprene copolymer, chlorinated Polysar EPDM 227 Polysar EPDM 345 Polysar EPDM 346 Polysar EPDM 545 Polysar EPDM 585 Polysar EPDM 847X Polysar EPDM 847 Polysar EPDM 865 Polysar EPDM 965. See EPDM rubber... 

Isobutylene/isoprene copolymer Isobutylene/isoprene copolymer, brominated Isobutylene/isoprene copolymer, chlorinated D-Mannitol 2,2 -Methylenebis 6-(1-methylcyclohexyl)-p-cresol Natural rubber Oleyl alcohol... 

Isobutylene/isoprene copolymer, chlorinated rubber, aerospace components Fluorosilicone elastomer rubber, antivibration mounts Isobutylene/isoprene copolymer, chlorinated rubber, automotive EPM rubber... 

Isobutylene/isoprene copolymer, chlorinated rubber, food-contact Sperm oil... 

Exxon butyl rubber and its chlorinated analog, chlorobutyl rubber are isobutylene-isoprene copolymers. They are basically inert, nonpolar, stable elastomers which exhibit outstanding resistance to attack by a great many different chemicals. 

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). 

Butyl rubber and other isobutylene polymers of technological importance iaclude various homopolymers and isobutylene copolymers containing unsaturation achieved by copolymerization with isoprene. Bromination or chlorination of the unsaturated site is practiced commercially, and other modifications are beiag iavestigated. 

Halogenated Butyl Rubber. Halogenation at the isoprene site ia butyl mbber proceeds by a halonium ion mechanism leading to a double-bond shift and formation of an exomethylene alkyl haUde. Both chlorinated and brominated mbber show the predominate stmcture (1) (>80%), by nmr, as described eadier (33,34). Halogenation of the unsaturation has no apparent effect on the isobutylene backbone chains. Cross-linked samples do not crystallize on extension due to the chain irregularities introduced by the halogenated isoprene units. 

The most industrially significant polymerizations involving the cationic chain growth mechanism are the various polymerizations and copolymerizations of isobutylene. In fact, about 500 million pounds of butyl rubber, a copolymer of isobutylene with small amounts of isoprene, are produced annually in the United States via cationic polymerization [126]. The necessity of using toxic chlorinated hydrocarbon solvents such as dichloromethane or methyl chloride as well as the need to conduct these polymerizations at very low temperatures constitute two major drawbacks to the current industrial method for polymerizing isobutylene which may be solved through the use of C02 as the continuous phase. 

Nearly 500 million pounds of butyl rubber are produced annually in the USA via cationic copolymerization of isobutylene and small amounts of isoprene [134]. The industrial methods for polymerizing isobutylene are plagued by two major drawbacks - the use of toxic chlorinated hydrocarbon solvents and the need to carry out these polymerizations at very low temperatures. Each of these drawbacks may be circumvented through the use of carbon dioxide as the continuous phase for polymerization. 

Butyl rubber consists mostly of isobutylene (95-98%) and about 2-5% isoprene units. 1 The isoprene unit is halogenated by either chlorine or bromine to obtain the corresponding halobutyl rubbers. Despite the superior elastomeric properties of halobutyl, the elastomer can easily undergo dehydrohalogenation leading to crosslinfang, and the isoprene unsaturation is subject to ozone cracking. To remedy these problems and to improve the halobutyl properties, a new class of elastomer poly(isobutylene-co-p-methylstyrene) [poly (IB-PMS)] was developed. Unlike butyl rubber, it contains no double bonds and therefore cannot be crosslinked unless otherwise functionalized. The chemical structures of butyl rubber and poly (IB-PMS) copolymers are shown below. 

Characteristic examples of industrial fast chemical reactions are the electrophilic polymerisation of isobutylene [7], its copolymerisation with isoprene [10], chlorination of olefins [17] and butyl rubber [18], ethylene hydrochlorination [17], sulfation of olefins [19], neutralisation of acidic and basic media [20], isobutene alkylation (production of benzines) [21-23], and so on. These examples of fast liquid-phase reactions and a variety of such processes assume a formal approach for their calculation and modelling, based on material and heat balance in the industrial implementation of respective products. It is a priori acknowledged that is not difficult to achieve an isothermic mode for fast chemical exothermic processes if you are aware of the process behaviour and can control it. 

Elastomers can be divided into two general categories, natural rubber and synthetic rubbers. Synthetic elastomers in turn are either termed general purpose rubbers (GPR) or special purpose rubbers. Natural rubber is generally obtained from southeast Asia or Africa. Synthetic rubbers are produced from monomers obtained from the cracking and refining of petroleum. The most common monomers are styrene, butadiene, isoprene, isobutylene, ethylene, propylene, and acrylonitrile. There are monomers for specialty elastomers which include acrylics, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohy-drin, ethylene-acrylic, ethylene-octene rubber, ethylene-propylene rubber, flu-oroelastomers, polynorbornene, polysulfides, sihcone rubber, thermoplastic elastomers, urethanes, and ethylene-vinyl acetate. 

The only cationic polymerization of major technological importance is the synthesis of butyl rubber by copolymerization of isobutylene with small quantities of isoprene at low temperature (e.g. — 90 C) using Lewis acid initiators (e.g. AlCy.and chlorinated solvents (e.g. chloromethane). 

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