Patent ID: 6197889
Filing Date: 2001-03-06
Classification: C08F

Abstract:
An elastomeric block copolymer of the structure(A-(B/A)).sub.n -A,X-[(B/A)-A).sup.n ].sub.m+1, orY-[(B/A)-A).sub.n ].sub.m+1,where A is a vinylaromatic block forming a hard phase, (B/A) is a random copolymer block of vinylaromatic monomer and of diene forming a soft phase, X is the radical of an (m+1)-functional initiator, Y is the radical of an (m+1)-functional coupling agent and m and n are natural numbers from 1 to 10,whereinthe elastomeric block copolymer has a monomer composition comprising 25-60% by weight of diene and 75-40% by weight of vinylaromatic compound,the glass transition temperature T.sub.g of block A is above 25.degree. C. and that of block (B/A) is below 25.degree. C., andthe proportion of the hard phase in the elastomeric block copolymer is from 5 to 40% by volume and the relative amount of 1,2 linkages of the polydiene, based on the sum of 1,2- and 1,4-cis/trans-linkages, is less than 15%.