Mobil Oil Corporation

Mobil Oil Co

Wen-Pao Wu

Charles M Krutchen

Edward A Colombo

Phillip A Williams

James E Blythe

A polystyrene resin in foam form having a basis weight of less than about 20 g/100 in.sup.2 and a density of about 6 lbs./ft.sup.3 or less, the foam precursor of which is either a polystyrene having a melt index of about 8 or more or a polystyrene in combination with a minor proportion of any other material which will result in a melt index of about 8 or more. A method of forming such a polystyrene resin foam structure includes combining the resin in molten form under pressure with the blowing agent of at least approximately 100% carbon dioxide and extruding the mixture through a die into an atmosphere of reduced pressure to form the foam structure.

High melt index polystytene foam and method

High melt index polystyrene foam and method

A thermoforming oven for the convection heating of a continuous web of a thermoplastic foam or film material which is being advanced through the oven towards a thermoformer. Moreover, there is disclosed to a method for the improved and more uniform convective heating of a thermoplastic foam or film material which is advanced through a thermoforming oven. A countercurrent flow of a gaseous heating medium is regulated and directed so as to impart the greatest degree of uniformity of temperature thereto during heating and blow-up to the thermoplastic material being advanced in an intermittent manner through the convective oven.

Convective thermoforming oven

A method for forming a molded thermoplastic foam structure comprising partially filling a mold with solvent imbibed particles of a thermoplastic resin, pressurizing said mold under conditions such as to prevent vaporization of said blowing agent during subsequent polymer melting, heating said polymer to a flowable state, releasing the mold pressure to permit foaming of the melt and expansion of the foamed polymer within the mold.

Thermoplastic foam molding

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.

Polymer foam, thermoformed shapes thereof and methods of forming same

Polymer foam, thermoformed shapes thereof and method of forming same

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.

Polymer foam, thermoformed shaped thereof and methods of forming same

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 imbided with methylene chloride, chloroform, 1,1,2-trichloroethane or mixtures thereof. A method of thermoforming said foam in sheet form.

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Victor, NY, United States of America

Wen-Pao Wu