B is a polymer block of a conjugated diene, the average molecular weight of the block being between about 15,000 and about 250,000; 3. the total blocks A being 10 to 35% by weight of the copolymer; B. 50 to 200 parts by weight of tackifying resin; C. 10 to 45 parts by weight of naphthenic plasticizer oil wherein the naphthenic content of the plasticizer oil based upon carbon content lies between 5