The Dow Chemical Company

John M Corbett

Chung P Park

Warren H Griffin

Richard E Skochdopole

Anthony L Scaggs

Frederick J Dechow

Charles R Bearden

Fred W Neumann

A flame retardant polymeric composition comprising a monoalkenyl aromatic polymer having polymerized therein from about 5 to about 25 mole percent of an imide having appended, to the nitrogen atom, a bromine substituted aliphatic hydrocarbon radical. The composition is formed by melt blending a copolymer of a monoalkenyl aromatic monomer and an ethylenically-unsaturated anhydride with a brominated, primary aliphatic amine.

Polymeric compositions possessing improved flammability resistance

High quality plastic foam and the like expanded products and articles are made by incorporating a blowing agent in an acid-containing alkenyl aromatic polymer, such as a copolymer of styrene and acrylic acid; extruding while cross-linking the polymer with a polyfunctional cross-linking agent.

Making cross-linked styrene polymer foam

Anhydride-containing thermoplastic polymers are foamed with ammonium carbonate, ammonium bicarbonate and ammonium oxalate to provide foams having good heat distortion characteristics and undesirable organic blowing agents are avoided.

Thermoplastic foam and process for the preparation thereof

Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resins having low stiffness, especially comprising copolymers consisting essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises the ethylenic polymer and a volatile mixed blowing agent. The starting polymers are preferably copolymers of ethylene and vinyl acetate having stiffness less than about 20,000 psi. The mixed blowing agents are particularly characterized as mixtures of dichlorodifluoromethane and at least one fluorocarbon constituent A, as defined. Exemplary mixtures contain (I) dichlorodifluoromethane and (II) from 35 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.

Soft ethylenic polymer foams

Cellular resin bodies having apparent density less than about 30 pounds per cubic foot, where the resin has highly crosslinked three-dimensional ethylenic polymer structure having amic acid groups and/or cyclic imide linkages, are made by reaction of polyisocyanates with certain polymerizable ethylenically unsatured dicarboxylic acid cyclic anhydrides illustrated by maleic anhydride, and water. Mixture of the reactants and heating cause chemical interaction, evolution of carbon dioxide, ethylenic polymerization of intermediate reaction product, crosslinking, foaming and hardening of the resin. Cell formation is caused by carbon dioxide and water vapor in the resin reaction product. Resin foam products are infusible and insoluble in usual solvents and resist ignition and burning in air.

Method for making crosslinked resin foams from an ethylenically

Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resins having low stiffness, especially comprising copolymers consisting essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises the ethylenic polymer and a volatile mixed blowing agent. The stating polymers are preferably copolymers of ethylene and vinyl acetate having stiffness less than about 20,000 psi. The mixed blowing agents are particularly characterized as mixtures of at least one fluorocarbon constituent I and at least one fluorocarbon constituent II, as defined. Exemplary mixtures contain (I) 1,2-dichloro-1,1,2,2-tetrafluoroethane and (II) from 25 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.

A monovinylidene aromatic polymer foam having reduced propensity to ignite is produced by (1) foaming a copolymer of monovinylidene aromatic monomer and an ethylenically unsaturated carboxylic anhydride wherein a portion of the copolymer contains halogen moiety and (2) subsequently crosslinking the copolymer foam by contacting it with a crosslinking agent such as alkylene polyamine. The resultant copolymer foam does not melt or drip upon exposure to flame.

Crosslinked styrene polymer foam having suppressed ignition properties

By the introduction of pendant phthalate, isophthalate or terephthalate half ester groups thermosettable vinyl ester resins can be successfully frothed using certain silicone frothing agents.

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Newark, OH, United States of America

John M Corbett