FIELD: chemistry.
SUBSTANCE: method for preparation of functionalised, bound or star-block copolymer used in sulphur-cured rubber composition containing carbon char and having in cured state decreased hysteresis with at least one of said blocks containing polyisoprene and at least one other block consisting of diene elastomer different from polyisopren with mole content of repeating units of one or more of conjugated dienes exceeding 15% includes: copolymerisation of one or more monomers containing at least one conjugated diene different from polyisoprene with catalitycal system containing hydrocarbon solvent halogenated or unhalogenated metal-organic compound A of the group IIIA metal, alkaline-earth metal compound B and polymer initiator C containing bound C-Li formed by unfunctionalised monolythium-containing polyisopren intended for formation of the said block or every polyisoprene block and (ii) adding to the product of the said polymerisation of the functionalising, binding or star-shape forming agent containing acetoxy group of formula Rn-Sn-(O-CO-R')4n> whereat n is integer natural number from 0 to 4 and R and R' each represents following groups: alkyl, cycloalkyl, aryl, aralkyl, same or different, for functionalisation or binding or forming of star-shape structure of the said block consisting of dien elastomer different from polyisopren. The said one or more polyisopren blocks have number average molecular mass Mn1 from 2500 to 20000 g/mole, the said one or more dien elastomer blocks have number average molecular mass Mn2 from 65000 to 350000 g/mole. Functionalised, bound or star-block copolymer, curable or cured rubber composition with lowered hysteresis in cured state, containing reinforcing filler completely or partially consisting of carbon char and containing aforementioned functionalised, bound or star-block copolymer are described also. Pneumatic tyre tread containing aforementioned rubber composition is described as well as pneumatic tyre containing described above tread.
EFFECT: hysteresis decrease of cured the rubber composition.
36 cl, 5 ex
