the units derived from the isoprene in block x when block x is a block of butadiene isoprene copolymer for example when block x is i b i b i b or i bi b bi i the weight ratio of butadiene to isoprene is preferably from 10 90 to 90 10 more preferably from 30 70 to 70 30 in the present multiblock interpolymers block y is a block of random copolymer of conjugated diene and monovinyl aromatic monomer suitable monomers are any conjugated diene and monovinyl aromatic monomer from which the random copolymer rubber block can be obtained the conjugated diene monomer is preferably a c 4 c 6 conjugated diene such as butadiene isoprene 1 3 pentadiene 1 3 hexadiene 2 3 dimethylbutadiene and mixtures thereof more preferably butadiene and isoprene most preferably butadiene the monovinyl aromatic monomer which is preferred in block y includes styrene or alkyl substituted styrene such as vinyl toluene all isomers u03b1 methylstyrene 4 tertiary butylstyrene 4 methylstyrene 3 5 diethylstyrene 3 5 di n butylstyrene 4 n propylstyrene 4 dodecylstyriene and mixtures thereof more preferably the monovinyl aromatic monomer is styrene vinyltoluene u03b1 methylstyrene and mixtures thereof with styrene being most preferred in block y the content of the recurring unit derived from the monovinyl aromatic monomer is generally 10 to 50 percent by weight preferably 15 to 35 percent by weight based on the total weight of block y and correspondingly the content of the recurring unit derived from the conjugated diene is generally 50 to 90 percent by weight preferably 65 to.