The Dow Chemical Company

Ronald E Snyder

Lu H Tung

Ronald R Pelletier

William A Gros

John F Vitkuske

James G Galloway

Jesse S Roeck

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.

Tapered block copolymers

Bituminous compositions and method of making

Disclosed are bituminous blends having improved toughness and elasticity. The blends contain an emulsion of a bituminous binder and an emulsion of 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 styrene content of about 20 to about 90 weight percent of the total monovinyl aromatic compound in the tapered block copolymer. Also disclosed is a method of applying the blends to various surfaces.

Bituminous compositions and methods of application to surfaces

The present invention provides for a method of converting an anionic latex to a cationic latex by the addition of a steric stabilizer and a cationic surfactant. The invention also provides for a method of using the cationic latex prepared by the conversion, in an asphalt emulsion. The converted latex provides improved torsional recovery properties to the cured asphalt emulsion.

Latex conversion to cationic form use, for example in cationic asphalt

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Midland, MI, United States of America

Ronald E Snyder