| abstract |
PURPOSE: To obtain a composition having excellent initial bond strength, mainte nance of adhesivity and discoloration stability with elapse of time and suitable as an adhesive by compounding a specific tribranched block copolymer, a dibranched block copolymer and a linear diblock copolymer at specific ratios. n CONSTITUTION: The objective composition is produced by compounding (A) a tribranched block copolymer expressed by formula I (A is aromatic vinyl polymer block; B is conjugated diene polymer block; X is tri or tetrafunctional alkoxysilane coupling agent residue; the weight ratio of A/B is 10/90 to 30/70) and having a molecular weight of 150,000-450,000 with (B) a dibranched block copolymer expressed by formula II (C is A; D is B; Y is 2-3 functional alkoxysilane coupling agent residue; the weight ratio of C/B is 10/90 to 30/70) and having a molecular weight of 100,000-300,000 and (C) a linear diblock copoly mer expressed by formula III (E is A; I is isoprene polymer unit; the weight ratio of E/I is 10/90 to 30/70) and having a molecular weight of 50,000-150,000 at a weight ratio (A/B) of 20/80 to 90/10 and that of (A+B)/C of 45/55 to 80/20. n COPYRIGHT: (C)1991,JPO&Japio |