butyl rubber


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Related to butyl rubber: Polyisobutylene

butyl rubber:

see rubberrubber,
any solid substance that upon vulcanization becomes elastic; the term includes natural rubber (caoutchouc) and synthetic rubber. The term elastomer is sometimes used to designate synthetic rubber only and is sometimes extended to include caoutchouc as well.
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Butyl Rubber

 

a synthetic rubber that is a product of the copolymerization of isobutylene (I) and a small quantity (1-5 percent) of isoprene (II); it has the general formula

Butyl rubber is obtained by the cationic copolymerization of monomers in a solution of methyl chloride or ethyl chloride at temperatures of about -100° C (the catalyst is aluminum chloride). Butyl rubber is a product of light-yellow color with a density of 920 kg/m3 (0.92 g/cm3), insoluble in alcohols, ethers, ketones, dichlorethane, aniline, and nitrobenzene and resistant to the action of water. Butyl rubber is characterized by low gas permeability, second in this respect only to polysulfide rubber: the coefficients of gas permeability for butyl rubber by hydrogen, oxygen, and nitrogen are 55 × 10-18, 9.9 × 10-18, and 2.47 × 10-18 m2/(sec . newton/m2), or 5.5 × 10-8, 0.99 × 10-8, and 0.247 × 10-8cm2/(sec. kg-force/cm2), respectively. The absence of double bonds in the majority of mers of the macromolecules of butyl rubber accounts for the resistance of butyl rubber to the action of oxygen, ozone, and light and, at the same time, also for the retarded vulcanization of the rubber. (So-called chlorbutyl rubber and brombutyl rubber, which significantly exceed initial butyl rubber in rapidity of vulcanization, are obtained by halogenization of butyl rubber.)

Butyl rubber is vulcanized by means of sulfur (in this case ultra-accelerators are used), dinitroso compounds, and alkyl-phenol-formaldehyde resins.

The capacity of butyl rubber to crystallize upon stretching makes it possible to obtain high-strength pure resins from it. Upon the introduction of active fillers (mainly carbon black), the strength is unchanged or in some cases even decreased, but the other physicochemical properties of cured rubbers made from butyl rubber are increased (see Table 1).

Table 1. Properties of pure and black-filled cured rubbers made from Soviet-made butyl rubber
 PureBlack-filled
1 TM-2 is a Soviet instrument for measuring microhardness
Tensile strength [MN/m2 (kgf/cm2)].............23 (230)23 (230)
Modulus when stretched 500% [MN/m2 (kgf/cm2)].............1.2(12)11 (110)
Tear resistance (kN/m or kgf/cm)985
Hardness according to TM-2 (arbitrary units)13065

The principal merits of cured rubbers made from butyl rubber are their resistance to the action of many aggressive mediums, including alkalies, hydrogen peroxide, and certain vegetable oils; high dielectric properties [specific volume electric resistance, 1014 ohms m (1016 ohms cm); dielectric permeability, 2.1-2.3], which are maintained after prolonged immersion of the cured rubbers in water; gas impermeability; and heat resistance. The cured rubbers made from butyl rubber that have the greatest heat resistance are those that are vulcanized with aklyl-phenol-formaldehyde resins. The disadvantages of cured rubbers made from butyl rubber are low rebound elasticity at room temperature (˜ 10 percent), high residual compressive strain, and high heat buildup under dynamic influences.

Butyl rubber is manufactured in the form of briquettes weighing about 30 kg. The commercial brands of butyl rubber include BK (USSR), Enjay Butyl and Bucar Butyl (USA), Esso Butyl (England), and Plastugil Butyl (France). The most important field of usage of butyl rubber is in tire production. In addition, butyl rubber is used in the manufacture of rubberized fabrics, various rubber products that are resistant to high temperatures and aggressive mediums, and so on. The production capacity for butyl rubber in the capitalist countries in 1970 was about 360, 000 tons.

butyl rubber

[′byüd·əl ‚rəb·ər]
(materials)
A synthetic rubber made by the polymerization of isoprene and isobutylene.

butyl rubber

Synthetic rubber that is made by the polymerization of isoprene and isobutylene; provides good resistance to aging, weathering, and high levels of moisture.
References in periodicals archive ?
Commenting on the halogenated butyl rubber unit, Mr Nikhil Meswani, Executive Director, RIL, said, "RSEPL's halogenated butyl rubber plant will be well-poised to capitalise on the significant surge in regional demand in tyre and pharmaceutical industries.
Increasing utilization of butyl rubbers for end-use applications such as tyre & tubes, various mechanical automotive components e.
Butyl rubber is of prime importance due to its wide ranging applications.
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The expansion is part of the firm's commitment to help meet increasing demand for butyl rubber and indicates the company's recent advances in process technology.
Next, the scientists blended the mixture into liquid butyl rubber.
The cost reductions will clearly be available in truck tyres which use a lot more butyl rubber.
Tire-curing bladder is commonly made of resin-cured butyl rubber because of its excellent thermal stability and air impermeability.
The ear pads are made of a soft and pliable butyl rubber material for an acoustic seal and the best hearing protection.
Four two-piece isolators--with a micro-cellular upper and butyl rubber lower--are fitted between the frame and body for greater road isolation.
The MBU-13/P oxygen hose is constructed of butyl rubber, has chemical resistant properties and can withstand temperatures of 275[degrees]F.
ExxonMobil Chemical Butyl Polymers business is the world's leader in butyl technology, services and products, with more than 65 years of butyl rubber experience.