Process for producing alkenyl aromatic foams using a combination of atmospheric and organic gases and foams produced thereby

Claim 2

A process for the production of alkenyl aromatic foams, said process comprising: (a) heating an alkenyl aromatic resin to a temperature above its melting point to form a melted alkenyl aromatic resin; (b) adding to the melted alkenyl aromatic resin a masterbatch mix comprised of: (i) encapsulated monosodium citrate and sodium bicarbonate; ii) styrene-ethylene/butylene-styrene block copolymer; (iii) alpha-methyl polystyrene; (iv) white mineral oil; and (v) silica, to form an alkenyl aromatic/masterbatch mix blend; (c) heating the alkenyl aromatic/masterbatch mix blend to a temperature sufficient to form a melted blend; (d) injecting into the melted blend a non-solid blowing agent comprised of a combination of atmospheric gas and organic gas to form an injected melted blend; (e) mixing the injected melted blend to form a mixed injected melted blend; and (f) cooling and extruding the mixed injected melted blend as an alkenyl aromatic foam.

Claim 3

A process for the production of alkenyl aromatic foams, having a density of greater than 2.5 lbs./ft 3 , said process comprising: (a) heating an alkenyl aromatic resin to a temperature above its melting point to form a melted alkenyl aromatic resin; (b) adding to the melted alkenyl aromatic resin a masterbatch mix comprised of: (i) a styrene resin; (ii) a rubbery block copolymer; and (iii)a solid blowing agent to form an alkenyl aromatic/masterbatch mix blend; (c) heating the alkenyl aromatic/masterbatch mix blend to a temperature sufficient to form a melted blend; (d) injecting into the melted blend a non-solid blowing agent comprised of a combination of atmospheric gas and organic gas to form an injected melted blend, wherein the atmospheric gas is present in an amount of at least about 30% by weight based upon the total weight of atmospheric gas and organic gas; (e) mixing the injected melted blend to form a mixed melted blend; (f) cooling the mixed injected melted blend; and (g) extruding the cooled blend at a temperature not below 120° C. as an alkenyl aromatic foam.

Claim 4

A process for the production of alkenyl aromatic foams, having a density of greater than 2.5 lbs./ft 3 , said process comprising: (a) heating an alkenyl aromatic resin to a temperature above its melting point to form a melted alkenyl aromatic resin; (b) adding to the melted alkenyl aromatic resin a masterbatch mix comprised of: (i) a styrene resin; (ii) a rubbery block copolymer; and (iii)a solid blowing agent to form an alkenyl aromatic/masterbatch mix blend; (c) heating the alkenyl aromatic/masterbatch mix blend to a temperature sufficient to form a melted blend; (d) injecting into the melted blend a non-solid blowing agent comprised of a combination of atmospheric gas and organic gas to form an injected melted blend, wherein the atmospheric gas is present in an amount of at least about 30% by weight based upon the total weight of atmospheric gas and organic gas; (e) mixing the injected melted blend to form a mixed melted blend; (f) cooling the mixed injected melted blend; and (g) extruding the cooled blend at a temperature not below 120° C. as an alkenyl aromatic foam.

Claim 5

A process for the production of alkenyl aromatic foams having a density of greater than 6.0 pounds per cubic foot, said process comprising: (a) heating an alkenyl aromatic resin to a temperature above its melting point to form a melted alkenyl aromatic resin; (b) adding to the melted alkenyl aromatic resin a masterbatch mix comprised of: (i) encapsulated monosodium citrate and sodium biocarbonate; (ii) styrene-ethylene/butylene-styrene block copolymer; (iii) alpha-methyl polystyrene; (iv) white mineral oil; and (v) silica, to form an alkenyl aromatic/masterbatch mix blend; (c) heating the alkenyl aromatic/masterbatch mix blend to a temperature sufficient to form a melted blend; (d) injecting into the melted blend a non-solid blowing agent comprised of a combination of atmospheric gas and organic gas to form an injected melted blend; (e) mixing the injected melted blend to form a mixed injected melted blend; (f) cooling the mixed injected melted resin; and (g) extruding the cooled blend as an alkenyl aromatic foam.

Claim 6

A process for the production of alkenyl aromatic foams having a density of greater than 6.0 pounds per cubic foot, said process comprising: (a) heating an alkenyl aromatic resin to a temperature above its melting point to form a melted alkenyl aromatic resin; (b) adding to the melted alkenyl aromatic resin a masterbatch mix comprised of: (i) encapsulated monosodium citrate and sodium biocarbonate; (ii) styrene-ethylene/butylene-styrene block copolymer; (iii) alpha-methyl polystyrene; (iv) white mineral oil; and (v) silica, to form an alkenyl aromatic/masterbatch mix blend; (c) heating the alkenyl aromatic/masterbatch mix blend to a temperature sufficient to form a melted blend; (d) injecting into the melted blend a non-solid blowing agent comprised of a combination of atmospheric gas and organic gas to form an injected melted blend; (e) mixing the injected melted blend to form a mixed injected melted blend; (f) cooling the mixed injected melted resin; and (g) extruding the cooled blend as an alkenyl aromatic foam.