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US 4,666,946 AGranted
Expandable polypropylene interpolymer particles
AssigneeAtlantic Richfield Company
InventorKent D. Fudge
Life of this patent
Estimating the term…
Abstract
Blends of polypropylene-poly(vinyl aromatic monomer) interpolymer with certain polymers and/or rubbers can be impregnated with blowing agents to give products which can be expanded under atmospheric steam conditions to give low density, fine cell structure foam particles.
Claims7
A process for producing expandable polypropylene particles comprising
- (a) forming a mixture of
- (1) 75-96% by weight of mixture of a polypropylene-poly(vinyl aromatic monomer) interpolymer made by polymerizing 40 to 80% by weight based on interpolymer of a vinyl aromatic monomer in the presence of an aqueous suspension of a copolymer of propylene and sufficient olefin co-monomer to give said copolymer a melting peak of less than 150.degree. C., and
- (2) 4-25% by weight of mixture of a polymer selected from the group consisting of polyethylene, ionomers, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, chlorinated polyethylenes, chlorosulfonated polyethylenes, ethylene-propylene-diene monomer rubbers, styrene-butadiene block copolymers, ethylene-propylene rubbers, and polyethylene-poly(vinyl aromatic monomer) interpolymer;
- (b) blending said mixture with 0-5% by weight based on blend of a lubricant and cell control agent and 0.005 to 0.5% based on blend of a peroxide at a temperature 175.degree. to 185.degree. C. to visc break the interpolymer of section (a) (1) above;
- (c) grinding, extruding and pelletizing said blend to form particles;
- (d) impregnating said blend with 3 to 20% by weight of blend of a blowing agent and 0-5% by weight of blend of a solvent, to give expandable blend particles which can be expanded under atmospheric steam conditions to fine cell structure foams of density less than 2.0 pounds per cubic foot.
3 more elements
A process for producing expandable polypropylene particles comprising
- (a) forming a mixture of
- (1) 75-96% by weight of mixture of a polypropylene-poly(vinyl aromatic monomer) interpolymer made by polymerizing 40 to 80% by weight based on interpolymer of a vinyl aromatic monomer in the presence of an aqueous suspension of a copolymer of propylene and sufficient olefin co-monomer to give said copolymer a melting peak of less than 150.degree. C., said interpolymer having been visc-broken to a higher melt flow;
- and
- (2) 4-25% by weight of mixture of a polymer selected from the group consisting of polyethylene, ionomers, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, chlorinated polyethylenes, chlorosulfonated polyethylenes, ethylene-propylene-diene monomer rubbers, styrene-butadiene block copolymers, ethylene-propylene rubbers, and polyethylene-poly(vinyl aromatic monomer) interpolymer;
- (b) blending said mixture with 0-5% by weight based on blend of a lubricant and cell control agent and 0 to 0.5% based on blend of a peroxide at a temperature of 175.degree. to 185.degree. C. to visc break the interpolymer of section (a) (1) above;
- (c) grinding, extruding and pelletizing said blend to form particles;
- (d) impregnating said blend with 3 to 20% by weight of blend of a blowing agent and 0-5% by weight of blend of a solvent, to give expandable blend particles which can be expanded under atmospheric steam conditions to fine cell structure foams of density less than 2.0 pounds per cubic foot.
4 more elements
Dependencies are inferred from the claim text.