Blends of different conjugated diene/monovinyl aromatic copolymers in bituminous based roofing and waterproofing membranes

Claim 1

A composition, suitable for use as a roofing material or as a waterproofing membrane having both high and low temperature desirable properties which comprises a. A first radial conjugated diene/monovinyl aromatic copolymer having a wt. average molecular weight (M w ) above 200,000 and a monomer ratio of from about 50/50 to about 85/15, represented by at least one of the formulas (A-B).sub.x Y or (A-B-A).sub.x Y wherein A represents an non-elastomeric poly(monovinyl aromatic) block containing 8-18 carbon atoms per molecule and B represents an elastomeric poly(conjugated diene) block, said diene contains 4 to 12 carbon atoms per molecule, Y is at least one atom derived from a polyfunctional treating agent used in the formation of the radial polymers and x represents the number of functional groups of said polyfunctional treating agent and is an integer equal to at least 3; b. A second conjugated diene monovinyl aromatic copolymer having an M w below 200,000 and being at least one of radial and linear, when radial the formula thereof being as above given in this claim and it having an M w in the range from 100,000 up to 200,000, and when linear represented by the formula AB, wherein A and B are as above given in this claim and having an M w in the range of from about 100,000 up to 200,000, the ratio of the high and low M w copolymers being in the range 13/1 to 1/13, and c. An asphalt having a penetration grade below about 300 (ASTM D5).