Adhesives made from polymer systems

摘要

The present invention relates to an adhesive, comprising at least one polymer system obtained by a process for reducing the melt viscosity of at least one polymer blend starting material, wherein the process comprises the step of treating at least one polymer blend with at least one radical donor under shear stress at a temperature above the softening point of said polymer blend.

主权项

1. An adhesive made by the process of:
(A) degrading a polymer system with a radical donor until the degraded polymer system has a melt viscosity of less than 50% than the non-degraded polymer at 200° C.; and (B) adding a tackifier;
wherein the degraded polymer system of the resulting adhesive consists of (a) 30 to 70 wt % of an elastomeric rubber selected from the group consisting of ethylene-propylene rubber copolymer, ethylene-propylene-diene rubber terpolymer, and mixtures thereof and (b) 30 to 70 wt % a semi-crystalline olefinic polymer or a blend of semi-crystalline olefinic polymers;wherein the semi-crystalline olefinic polymer has a heat of melting from 20 to 95 J/g;wherein the degraded polymer system is present at a level greater than 30 wt %, based on the total weight of the adhesive; andwherein the molecular weight distribution Mw/Mn of the degraded polymer system ranges from 1.6 to 4.0.