Ronald G Snyder

US Patent:

52349993, Aug 10, 1993

Filed:

Nov 26, 1991

Appl. No.:

7/800342

Inventors:

Lu H. Tung - Oakland CA
Ronald R. Pelletier - Midland MI
Ronald E. Snyder - Midland MI
William A. Gros - Baton Rouge LA

Assignee:

The Dow Chemical Company - Midland MI

International Classification:

C08F 832

US Classification:

525314

Abstract:

Disclosed are bituminous blends having improved toughness and elasticity. The blends contain a bituminous binder and a tapered block copolymer formed from a monovinyl aromatic compound and a conjugated diene. Suitable tapered block copolymers include a tapered A-B-A type block copolymer of the A-t-B-t-A configuration, particularly those having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent, and tapered A-B-A type block copolymers of the A-B-t-A configuration having an isolated monovinyl aromatic compound content of about 20 to about 90 weight percent of the total monovinyl aromatic compound in the tapered block copolymer. Further disclosed is a method of making the blends. Further disclosed is a tapered A-B-A type block copolymer having an isolated monovinyl aromatic compound content of about 29 to about 75 weight percent.