Improved adhesive and polymer for adhesives

摘要

It has been discovered that block copolymers comprising at least two polymer blocks containing a vinyl aromatic hydrocarbon monomer contributed units and at least one polymer block conjugated diene monomer contributed units exhibit desirable adhesive properties. The vinyl aromatic hydrocarbon content ÄSÜ of the instant block copolymers is 25% to 60% by weight and the vinyl content of the conjugated diene portion ÄVÜ is 30% to 70%. The relationship between the vinyl aromatic hydrocarbon content ÄSÜ and the vinyl content of the conjugated diene portion ÄVÜ satisfies the formula: <MATH> According to the instant invention, adhesive compositions may be prepared which contain about 10% to about 50% of the block copolymers, about 20% to about 80% of a compatible tackifying resin; about 10% to about 40% of a platicizing oil; about 0.2% to about 2.5% of various stabilizers and 0% to about 10% of a compatible wax.