The Dow Chemical Company

John F Vitkuske

Lu H Tung

Corwin J Bredeweg

Ronald R Pelletier

William A Gros

Ronald E Snyder

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.

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

Novel copolymer blends comprising (a) a copolymer of alkenyl aromatic monomers containing from about 10 to about 70 percent by weight of an isopropenyl aromatic monomer, (b) a block copolymer of polystyrene blocks and conjugated diene blocks containing from about 15 to about 50 weight percent conjugated diene, (c) a block copolymer of polystyrene and conjugated diene blocks containing from about 55 to about 80 weight percent conjugated diene, and (d) 15 to 50 weight percent of a semicrystalline polyolefin.

Copolymer blends

Novel copolymer blends comprising (a) a copolymer of alkenyl aromatic monomers containing from about 10 to about 70 percent by weight of an isopropenyl aromatic monomer, (b) a block copolymer of polystyrene blocks and conjugated diene blocks containing from about 50 to about 80 weight percent conjugated diene, and (c) 15 to 50 weight percent of a semicrystalline polyolefin.

Novel copolymer blends comprising (a) a copolymer of alkenyl aromatic monomers containing from about 10 to about 70 percent by weight of an isopropenyl aromatic monomer, (b) a block copolymer having an alkenyl aromatic monomer blocks and polybutadiene blocks containing from about 10 to about 70 percent by weight isopropenyl aromatic monomer in the alkenyl aromatic block and from about 15 to about 50 weight percent butadiene, (c) a block copolymer having alkenyl aromatic monomer blocks and polybutadiene blocks containing from about 10 to about 70 percent by weight isopropenyl aromatic monomer in the alkenyl aromatic monomer and from about 55 to about 80 weight percent butadiene, and (d) a polyolefin.

Block copolymers of the AB(BA).sub.n configuration are employed in the preparation of asphalt blend concentrates. Advantageously asphalt is blended with polymer solution from polymerization reactor and subsequently devolatilized.

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Midland, MI, United States of America

John F Vitkuske