PURPOSE: To provide an AB-block copolymer based on butadiene, isoprene, and styrene capable of providing a tread of tire excellent in wet surface sliding resistance by copolymerizing butadiene-1,3, isoprene and styrene at a specified mole ratio to manufacture a block A, and adding a catalyst followed by polymerization to manufacture a block B.
CONSTITUTION: A monomer composition consisting of 20-75% butadiene-1,3, 5-50% of isoprene, and 3-30% of styrene is anion-polymerized in an inert organic solvent (e.g.; hexane) under the presence of a catalyst (e.g.; butyl lithium) consisting of a slight quantity of an organic Li compound as occasion demands to manufacture 30-90% of a block A. The above catalyst is added to perform the polymerization to the end, and a block B having average vinyl group content and isoprene group content larger than the block A by 30% is generated, whereby an unsaturated AB-block copolymer based on butadiene, isoprene and styrene is provided.
UARUTERU HERERUMAN
HANSUUBERUNTO FUTSUKUSU
KAARUHAINTSU NORUTOJIIKU
YURUGEN UORUPERUSU
