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 foam structure having a density of less than about 20 lbs/ft.sup.3. The method of forming the same comprising forming a homogeneous melt blend under pressure of a polymer member selected from the group consisting of polyetherimide resin particles, polycarbonate resin particles, a polymer blend of polyphenylene oxide and polystyrene in particle form imbibed with a blowing agent, followed by extrusion of the same into a lower pressure atmosphere. A composition comprising said particles imbibed with methylene chloride, chloroform, 1,1,2-trichloroethane or mixtures thereof. A method of thermoforming said foam in sheet form.
Claims6
The process of preparing a low density polymer foam structure, said polymer being a solvent imbibable blend of polyphenylene oxide and a high impact polystyrene comprising:
- (a) providing said polymer blend in particle form imbibed with a solvent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof;
- (b) homogeneously melt blending said particles and solvent in an extrusion system under pressure;
- and
- (c) extruding said melt blend into a lower pressure atmosphere to cause said solvent to vaporize yielding a foam structure said foam structure having a density of less than about 20 lbs./ft.sup.3.
The method of preparing a thermoformed structure of a polyphenyl oxide a high impact polystyrene blend in foam form comprising:
- (a) subjecting a sheet of said foam having a density of less than 20 lbs./ft.sup.3 to a first temperature sufficient to permit a shaped formation to be effected therein;
- (b) effecting a shape in said sheet while it is at said temperature;
- and
- (c) reducing the temperature of said sheet to a second temperature permitting permanent retention of said shape in said sheet at or below said second temperature.
Dependencies are inferred from the claim text.