Method for making closed-cell soft ethylenic polymer blend foams and foams thus obtained

Claim 1

A method for making soft ethylenic polymer resin blend foams having substantially closed-cell structure, dimensional stability, and flexural modulus less than about 150 psi which comprises forming under heat and pressure a flowable gel composition of: (A) an ethylenic polymer resin blend having low stiffness less than about 20,000 psi consisting essentially of (1) 40 to 90 percent by weight of a copolymer consisting essentially of ethylene and 3 to 15 percent by weight based on copolymers of a monoethylenically unsaturated carboxylic acid, containing no salt thereof, in admixture with (2) 10 to 60 percent by weight of a copolymer consisting essentially of ethylene and 5 to 45 percent by weight based on copolymer of at least one monoethylenically unsaturated non-ionic comonomer; and (B) at least one C 2-4 fluorocarbon blowing agent having normal boiling point between -30 to 30 ° C and a value for the critical quantity (T b -0.5V c ) of between 110 to 145, where T b is the normal boiling point temperature of the fluorocarbon in degrees Kelvin and V is its critical volume in cubic centimeters per gram-mole, there being up to 0.35 gram--mole of blowing agent per 100 grams of resin blend in the flowable gel, and extruding the gel to ambient air atmosphere whereby the blowing agent forms gas cells in the polymer resin blend.

Claim 2

A method for making soft ethylenic polymer resin blend foams having substantially closed-cell structure, dimensional stability, and flexural modulus less than about 150 psi which comprises forming under heat and pressure a flowable gel composition of: (A) an ethylenic polymer resin blend having low stiffness less than about 20,000 psi consisting essentially of (1) 40 to 90 percent by weight of a copolymer consisting essentially of ethylene and 3 to 15 percent by weight based on copolymers of a monoethylenically unsaturated carboxylic acid, containing no salt thereof, in admixture with (2) 10 to 60 percent by weight of a copolymer consisting essentially of ethylene and 5 to 45 percent by weight based on copolymer of at least one monoethylenically unsaturated non-ionic comonomer; and (B) at least one C 2-4 fluorocarbon blowing agent having normal boiling point between -30 to 30 ° C and a value for the critical quantity (T b -0.5V c ) of between 110 to 145, where T b is the normal boiling point temperature of the fluorocarbon in degrees Kelvin and V is its critical volume in cubic centimeters per gram-mole, there being up to 0.35 gram--mole of blowing agent per 100 grams of resin blend in the flowable gel, and extruding the gel to ambient air atmosphere whereby the blowing agent forms gas cells in the polymer resin blend.