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US 4,598,101 AGranted
Polymer foam, thermoformed shapes thereof and methods of forming same
AssigneeMobil Oil Corporation
InventorsCharles M. Krutchen, Wen-Pao Wu
Life of this patent
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Abstract
A polyphenylene oxide/polystyrene polymer blend foam structure having a density of less than about 20 lbs/ft.sup.3. The method of forming said foam comprising combining the polymer blend with a blowing agent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof in molten form under pressure and extruding the same into a lower pressure region to form the foam.
Claims2
The process of preparing a low density resin blend foam structure comprising:
- (a) providing a blend of polyphenylene oxide and a high impact polystyrene in an extrusion system under pressure and melting the same;
- (b) homogeneously mixing the molten polymer blend with a blowing agent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof, said blowing agent being present in a proportion sufficient to foam the polymer blend to a density less than about 20 lbs./ft.sup.3 ;
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- (c) extruding the melt blend into a lower pressure atmosphere to cause the blowing agent to vaporize yielding a polyphenylene oxide/high impact polystyrene blend foam structure.
1 more element
Dependencies are inferred from the claim text.