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 ?
Unlike curing of devulcanized carbon black-filled EPDM [17] and unfilled butyl rubber [29], the rubber derived from devulcanized tire-curing bladder does not exhibit minimum torque on curing curves.
The Butyl Rubber industry development trends and marketing channels are analyzed.
Butyl rubber has excellent impermeability to air and moisture, which leads directly to the most important application of this polymer: the inner liner in automobile tires.
The cost reductions will clearly be available in truck tires which use a lot more butyl rubber.
The subject has received little attention, mainly because of the assumed hydrophobic nature of most matrix elastomers, including butyl rubber.
Halogenated butyl rubber (HIIR) is a modification of butyl rubber (IIR), in other words, IIR is the raw material of HIIR.
Key statement: A tire having a decorative sidewall feature, the decorative sidewall feature being based upon a rubber composition, the rubber composition comprising between 15 and 25 parts by weight per 100 parts by weight of rubber (phr) of a highly unsaturated diene elastomer, between 60 and 80 phr of a butyl rubber and between 5 and 15 phr of an EPDM elastomer characterized as having an ethylene content of between 65 wt.
Henkel now offers a significantly more durable alternative with its Terostat 285 sealant based on butyl rubber.
The largest investment project yet from Lanxess, its 400 million [euro] 100,000 tonnes capacity butyl rubber plant to be built in Singapore, has been delayed due to the global economic crisis.
TEK-RAP was the first of its kind to use a co-extruded polyethylene butyl rubber coating system for external protection of line pipe.
The importance of butyl rubber is linked to the role it played as a replacement for tire inner tubes and curing bladders during World War II.
A general improvement in compatibility and adhesion with general purpose rubbers is also observed upon halogenating regular butyl rubber.