Styrene → Styrene-butadiene-styrene

Participants

Reaction Steps

Into a reaction vessel with a stirrer, 50 kg of cyclohexane, 1,750 g of well dehydrated styrene and 210 g of sec-butyl lithium (10% by weight, cyclohexane solution) were charged to carry out polymerization at 60° C. for 60 minutes. Next, 250 g of tetrahydrofuran was added and 6,500 g of butadiene was also added to carry out polymerization for 60 minutes. Then, 1,750 g of styrene was further added to carry out polymerization for 60 minutes. Thereafter, methanol was added to terminate the reaction. Thus, a styrene-butadiene-styrene type block copolymer was obtained. The block copolymer obtained was subjected to hydrogenation under the same conditions as in Reference Example 1 to give a hydrogenated product of the block copolymer (hereinafter simply referred to as "SEBS"). The SEBS thus obtained had a number average molecular weight of 76,100 and a styrene content of 35% by weight, where the ratio of hydrogenation was 98.9%.

Provenance & Evidence