COUPLED RESINOUS DIENE COPOLYMER WITH GOOD INTEGRAL HINGE FLEX LIFE AND HIGH HARDNESS

摘要

COUPLED RESINOUS DIENE COPOLYMERWITH GOOD INTEGRAL HINGE FLEX LIFE AND HIGH HARDNESSAbstract of the DisclosureA conjugated diene/monovinyl-substituted aromatic compound resinouscopolymer such as a styrene/butadiene block copolymer is produced using twoadditions of the monovinyl-substituted aromatic component and initiator in amanner such that the product has 71 to 81 wt. percent mono-vinyl-substitutedaromatic component and has a ratio based on the number average molecularweight of monovinyl-substituted aromatic component blocks in first and secondpolymer chains thus produced prior to coupling within the range of 3 to 7.The final product resulting from coupling such polymers has long integralhinge flex life and high hardness. This is accomplished by using no morethan 5 millimoles of initiator per mole of monomer in the second addition.