Slush molding process
AssigneeE. I. Du Pont de Nemours and Company
InventorsKarlheinz Hausmann, George K. Kodokian, George W. Prejean
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Abstract
A slush molding process in which the moldable thermoplastic composition powder dosed to the mold is prepared by blending ethylene carboxylic acid copolymers or ionomers with ethylene/glycidyl acrylate or methacrylate copolymer and cross-linking promoter at a temperature and for a time that does not cause significant cross-linking prior to dosing to mold, which is held for sufficient time and temperature to cause cross-linking in-situ, and optionally, other additives including release agents.
Claims10
A method of slush molding having steps of dosing a powder to a mold heated to a given temperature thus obtaining layer of partially or completely melted powder on the mold, heating mold to complete melting, cooling mold with suitable cooling means to form a film, and stripping film from mold, said method characterized by:
- a) said powder dosed to mold comprising
- i) 5-95% by weight of an acid copolymer comprising at least 50% by weight of ethylene, 1-35% by weight of an unsaturated carboxylic acid, and 0-49% by weight of a moiety selected from at least one of alkyl acrylate, alkyl methacrylate, vinylether, alkylene, carbon monoxide and sulphur dioxide;
- ii) 95-5% by weight of a cross-linking copolymer comprising at least 50% by weight of ethylene, 0.5-25% by weight of at least one reactive moiety selected for the group consisting of
- (i) an unsaturated epoxide of 4-11 carbon atoms,
- (ii) an unsaturated isocyanate of 2-11 carbon atoms,
- (iii) an alkoxy or alkyl silane wherein the alkyl group is from 1-12 carbon atoms,
- (iv) an alkyl halide, and
- (v) oxazoline, and
- 0-49% by weight of a moiety selected from at least one of an alkyl acrylate, alkyl methacrylate, vinylether, alkylene, carbon monoxide and sulphur dioxide, where the alkyl and ether groups are of 1-12 carbon atoms;
- and
- iii) a cross-linking promoter;
- wherein said powder is made by blending the components for a time at a temperature below that at which substantial cross-linking occurs;
- and
- b) mold is heated to complete melting at a sufficient temperature and is held for sufficient time to cross-link the melted film in-situ.
Dependencies are inferred from the claim text.