Solvent resistant thermoplastic polymers

Claim 2

A thermoplastic three-block polymer composition of claim 2 wherein the amount of styrene is about 20 to 35 percent by weight based on the total polymer, the amount of 1,3 butadiene or isoprene is about 50 to 75 percent by weight, and the amount of the acrylonitrile or methacrylonitrile is about 6.5 to 25 percent by weight.

Claim 3

A thermoplastic three-block polymer composition of claim 3 wherein the molecular weight of the styrene block is about 5,000 to 40,000, the molecular weight of the 1,3-butadiene or isoprene block is about 20,000 to 100,000 and the molecular weight of the acrylonitrile or methacrylonitrile block is about 5,000 to 40, 000.

Claim 4

A process for preparing a thermoplastic three-block polymer composition which comprises (a) reacting a vinyl-substituted aromatic hydrocarbon monomer in an inert hydrocarbon solvent and at a temperature between about 20* and 100* C. with about 0.1 to 15 milligrams per gram vinyl-substituted aromatic hydrocarbon monomer of an organolithium compound of the formula R-Li wherein R is an aliphatic, aromatic or cycloaliphatic hydrocarbon radical containing from one to 12 carbon atoms, until substantially all the monomer has polymerized; (b) adding to this reaction mixture a conjugated diene monomer and reacting until substantially complete conversion of the conjugated diene monomer; and (c) lowering the temperature of the reactor to about 10* to -100* C., charging an Alpha , Beta -olefinically unsaturated nitrile monomer so that 0.5 to 20 milligrams initiator per gram nitrile monomer is present and maintaining the polymerization temperature between about 10* and -100* C. until the desired degree of polymerization has been achieved.

Claim 5

The process for preparing a thermoplastic three-block polymer composition of claim 5 wherein the vinyl-substituted aromatic hydrocarbon monomer is styrene, the conjugated diene monomer is selected from the group consisting of 1,3-butadiene or isoprene, and the Alpha , Beta -olefinically unsaturated nitrile monomer is selected from the group consisting of acrylonitrile or methacrylonitrile.

Claim 6

The process for preparing a thermoplastic three-block polymer composition of claim 5 wherein the amount of organolithium initiator employed in step (a) is about 0.5 to 10 milligrams per gram of vinyl-substituted aromatic hydrocarbon monomer charged, the temperature of polymerization of step (a) is about 20* to 60* C. and the temperature of polymerization of step (b) is about 30* to 50* C.

Claim 7

The process for preparing a thermoplastic three-block polymer composition of claim 7 wherein the polymerization temperature of step (c) is between about -10* and 80* C. and the Alpha , Beta -olefinically unsaturated nitrile monomer is charged so that about 1 to 15 milligrams organolithium initiator per gram Alpha , Beta -olefinically unsaturated nitrile monomer is present.

Claim 8

The process for preparing a thermoplastic three-block polymer composition of claim 8 wherein the vinyl-substituted aromatic hydrocarbon monomer is styrene, the conjugated diene monomer is selected from the group consisting of 1,3-butadiene or isoprene, and the Alpha , Beta -olefinically unsaturated nitrile monomer is selected from the group consisting of acrylonitrile or methacrylonitrile.