Hot melt pressure sensitive adhesives - based on hydrogenated block copolymers of vinyl! aromatic(s) and butadiene!

摘要

Compsns. consist of mixts. of (a) 100 pts. block copolymer of A-B type, (in which A is a mono-vinyl aromatic block and B a butadiene block), selectively hydrogenated to reduce the olefinic C=C bonds to 5%; B has a 1,2-vinyl content before hydrogenation of 20-70 wt.%; A constitutes 20-50 wt.% of the copolymer, which has Mn 20,000-200,000, (b) 25-300 pts. tackifying resin, and (c) 0-200 pts. rubber extender oil. Used as pressure sensitive adhesives on self-adhesive materials e.g. films, labels, floor and wall coverings, medical plasters and anti-drumming materials. Adhesive has high heat and oxidn. resistance, with lower melt viscosity and better adhesion properties than hydrogenated copolymers of A-B-A type. The bonds show better cohesion than those from unhydrogenated copolymers of A-B type.