Tetrafunctional initiator
AssigneeNOVA Chemicals Inc.
InventorsSteven M. Krupinski, Robert J. Gorka
Life of this patent
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Abstract
The melt of polyvinyl aromatic polymers comprising from 10 to 45 weight % of star branched polymer prepared using a combination of thermal and tetra functional peroxide initiation has an improved melt strength permitting better foam formation for extrusion foam blown with conventional blowing agents and inert gases including CO2 and an improved tensile strength for oriented polystyrene (OPS) articles, e.g. blown film or extruded sheet.
Claims20
A polymer composition comprising C8-12 vinyl aromatic polymer prepared by polymerization in the presence of from 0.01 to 0.1 weight % of a tetra functional peroxide initiator of the formula:
- wherein R1 is selected from the group consisting of C4-6 t-alkyl radicals and R is a neopentyl group, in the absence of a cross linking agent, comprising:
- i) from 60 to 100 weight % of one or more C8-12 vinyl aromatic monomers;
- and
- ii) from 0 to 40 weight % of one or more monomers selected from the group consisting of C1-4 alkyl esters of acrylic or methacrylic acid and acrylonitrile and methacrylonitrile;
- which polymer may be grafted onto or occluded within from 0 to 12 weight % of one or more rubbery polymers selected from the group consisting of:
- iii) co- and homopolymers of C4-5 conjugated diolefins;
- and
- iv) copolymers comprising from 60 to 85 weight % of one or more C4-5 conjugated diolefins and from 15 to 40 weight % of a monomer selected from the group consisting of acrylonitrile and methacrylonitrile, said vinyl aromatic polymer comprising about 10 to about 50 weight % of a star branched polymer.
An oriented polystyrene article comprising from C8-12 vinyl aromatic polymer prepared by polymerization in the presence of from 0.01 to 0.1 weight % of tetra functional peroxide initiator of the formula:
- wherein R1 is selected from the group consisting of C4-6 t-alkyl radicals;
- and R is a neopentyl group, in the absence of a cross linking agent, comprising:
- i) from 60 to 100 weight % of one or more C8-12 vinyl aromatic monomers;
- and
- ii) from 0 to 40 weight % of one or more monomers selected from the group consisting of C1-4 alkyl esters of acrylic or methacrylic acid and acrylonitrile and methacrylonitrile;
- which polymer may be grafted onto or occluded within from 0 to 12 weight % of one or more rubbery polymers selected from the group consisting of:
- iii) co-and homopolymers of C4-5 conjugated diolefins;
- and
- iv) copolymers comprising from 60 to 85 weight % of one or more C4-5 conjugated diolefins and from 15 to 40 weight % of a monomer selected from the group consisting of acrylonitrile and methacrylonitrile,
- said vinyl aromatic polymer comprising about 10 to about 50 weight % of a star branched polymer.
Dependencies are inferred from the claim text.