FR1604583A - Mixtures of alfin polymers and polybutadiene for use in - Google Patents

Abstract

A rubber-based composition contains (a) a rubbery Alfin polymer with a molecular weight of 2,000,000 and (b) is not 5 weight %, based on the weight of (a) + (b), of a polybutadiene containing is not about 85% of cis-1,4 units. The compositions are used for tyre treads. The compositions have excellent wear properties. The tyres have good anti-skid, braking and steering properties. (a) The Alfin polymer is preferably prepared from a C is not >12, particulary A C4-12, diolefine, which may be copolymerised with other diolefinic compounds or with monomers such as styrene; other suitable monomers include 3-furyl- and 3-methoxy-butadine, p-methoxystyrene, vinylnaphthalene and vinylcyclohexane. The copolymers generally contain is not 50 weight % of conjugated olefine. The catalyst contains an alkenylsodium, a sodium alkoxide and a halide of an alkali metal. The molecular weight regulators are particularly 1,4-dihydro-benzene or -naphthalene. Polymerisation is in the presence of a diluent. The (co)polymers preferably have a molecular weight of 200,000-750,000, and a Mooney viscosity of 30-80. When the composition is to be used for tyre treads, the Alfin (co)polymer is preferably diluted with 30-150, generally 80-100, parts of an oil per 100 parts of (co)polymer. (b) The amount of polybutadiene is 5-50 weight %. For tyre treads, the composition also contains a carbon black.