Isoprene → 1,3-Butadiene

Polymerization steps (1) to (3) were conducted similarly to Reference Example 1 except that an equimolar mixture of butadiene and isoprene was used instead of isoprene in the polymerization step (2) described in Reference Example 1; the amounts of butadiene and isoprene charged to the reaction vessel were changed so that the content of the butadiene polymer block in the triblock copolymer before hydrogenation are as shown in Table 1; and the polymerization time was changed to 2 hours, 6 hours and 2 hours in the polymerization steps (1) to (3), respectively. The polymerization was conducted to give a triblock copolymer of a butadiene polymer block-copolymer block of butadiene and isoprene-butadiene polymer block. Concerning the triblock copolymer obtained, the number-average molecular weight of the block copolymer, the number-average molecular weight of each of the butadiene polymer block and the copolymer block of butadiene and isoprene, the content of the butadiene polymer block in the block copolymer, and the 1,2-bond content in the butadiene polymer block are shown in Table 1. The triblock copolymer obtained was subjected to hydrogenation as in the step (4) of Reference Example 1 to give a hydrogenated triblock copolymer. The degree of hydrogenation of each of the butadiene polymer block and the copolymer block of butadiene and isoprene in the hydrogenated triblock copolymer, and the glass transition temperature and the heat of crystalline fusion of the hydrogenated copolymer block of butadiene and isoprene are shown in Table 1.

1. customwas used instead of isoprene in the polymerization step (2)

ORD record

ord-083c03015ae044d1a23dec8625ed5d3e

Source dataset

uspto-grants-1999_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05900465