| 摘要 |
A conjugated diene/monovinyl-substituted aromatic compound resinous copolymer such as a styrene/butadiene block copolymer is produced using two additions of the monovinyl-substituted aromatic component and initiator in a manner such that the product has 71 to 81 wt. percent monovinyl-substituted aromatic component and has a ratio based on the number average molecular weight of monovinyl-substituted aromatic component blocks in first and second polymer chains thus produced prior to coupling within the range of 3 to 7. The final product resulting from coupling such polymers has long integral hinge flex life and high hardness. This is accomplished by using no more than 5 millimoles of initiator per mole of monomer in the second addition. |
