Abstract: Disclosed is a foamable styrenic polymer gel capable of forming a closed-cell foam structure, comprising: a) a flowable melt of a styrenic polymer material comprising greater than 50 percent by weight styrenic monomeric units and about 0.1 to about 40 percent by weight of oxygen-containing monomeric units based upon the total weight of the styrenic polymer material; and b) a blowing agent comprising about 5 weight percent or more carbon dioxide based upon the total weight of the blowing agent. Further disclosed is a process for making the foam structure. The oxygen-containing comonomer content in the styrenic polymer material enables process operating pressures to be significantly reduced when using carbon dioxide as a blowing agent compared to a styrenic polymer material without comonomer content. The foam structure formed is of low density and of good quality.

Abstract: Dense star polymers or dendrimers, modified by capping with a hydrophobic group capable of providing a hydrophobic outer shell, act as molecular nucleating agents. These modified dense star polymers or dendrimers are particularly effective for the production of small cell foams.

Abstract: A process for producing shaped foamable parts from a polymer composition containing polymer and a foaming and curing additive package which includes the steps of:(a) dry blending at least the blowing agent part of the foaming and curing additive package of the composition with a wax powder to produce a dry blend;(b) melt blending the dry blend and any residual parts of the composition at a temperature between the melting point and not more than 10.degree. C., preferably not more than 5.degree. C., above the melting point using a low shear condition to produce a melt blend;(c) molding the melt blend within the temperature and shear conditions of step (b).Foamable parts having good foam characteristics can be made on an industrial scale. The closed-foam cells are even. The foam adheres to metal surfaces.

Abstract: Disclosed is a foamable styrenic polymer gel containing an aqueous blowing agent capable of forming a closed-cell, unimodal foam structure. The gel composes in admixture the flowable melt of a polymer composition having greater than 50 percent by weight of a styrenic polymer and a blowing agent having about 1 percent or more by weight water based upon the total weight of the blowing agent. The styrenic polymer has a degree of water solubility sufficient to ensure formation of a unimodal foam structure instead of a bimodal foam structure. The unimodal cell size distribution provides desirable fabricability and machinability characteristics for the foam structure.

Abstract: Disclosed is a flexibilized, insulative styrenic polymer foam structure comprising a foam of a polymeric composition of a styrenic polymer greater than 50 percent by weight styrenic monomeric units, the foam having relatively larger primary cells with an average cell size range of about 0.05 to about 1.2 millimeters and relatively smaller secondary cells ranging in cell size from about 5 percent to about 50 percent of the average cell size of the primary cells. The primary and secondary cells constitute at least about 90 percent of the total cell volume within the foam structure. Between 1 and 30 percent by number of the cells have microscopic "pinholes" between them. The presence of the pinholes enhances the flexure of the foam structure. Further disclosed is a method of insulating a surface comprising applying to the surface an insulating panel fashioned from the structure of claim 1.

Abstract: Disclosed is an ethylenic polymer foam structure comprising an ethylenic polymer material. The ethylenic polymer material contains a substantially linear ethylenic polymer having: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .gtoreq.(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having about the same I.sub.2 and M.sub.w /M.sub.n. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional stability and foam quality associated with those structures. The foam structures have foam quality similar to those made with conventional LDPE but with enhanced toughness and elasticity. Further disclosed is a process for making the above foam structure and making it in a foam bead form.

Abstract: A foamed cellular material from polyester resins is obtained by extrusion foaming of polyester resins having melt strength higher than 8 centinewton, intrinsic viscosity greater than 0.8 dl/g and complex melt viscosity higher than 25,000 poises.

Abstract: A foamed polyester sheet of this invention has uniform fine cells and a high foaming ratio. Particularly, a sheet containing a polycarbonate resin or a polyarylate resin is excellent in high-temperature stability. The foamed polyester sheet of this invention is suited for use requiring a high-temperature stability, such as a container for an electronic oven, etc.

Abstract: The present invention relates to the continuous production of polyurethane and polyurethane urea elastomers by reaction of polyisocyanates with isocyanate-reactive compounds in a mixing nozzle.

Abstract: A process for producing hollow particles of crosslinked melamine resin having a uniform particles diameter, said process comprising subjecting a water-soluble methyl-etherified-melamine resin precondensate to condensation reaction in the presence of a curing catalyst in an aqueous solution containing a water-soluble polymer with carboxyl groups or water-soluble copolymer of ethylenically unsaturated carboxylic acid monomer, when the reaction liquid becomes turbid, adding to the reaction mixture a substance which dissolves or swells the melamine resin, and continuing the condensation reaction, if necessary.

Abstract: A game ball core comprising a thermoplastic resin or blend of resins, a chemical blowing agent, a nucleating agent, peroxide crosslinking agent and other minor additives is disclosed. The molded cellular core is sufficiently durable to withstand a synthetic cover molding process at elevated temperatures.

Abstract: 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.

Abstract: Disclosed is a process for making a low density, dimensionally-stable, open-cell, extruded propylene polymer foam comprising primarily an expanded propylene polymer material wherein the foam has a blowing agent comprising greater than 85 percent by weight of one or more organic blowing agents based upon the total weight of the blowing agent. The propylene polymer material comprises more than 50 weight percent or more of propylene monomeric units based upon the total weight of the propylene polymer material. The foam has a density about 96 kilograms or less per cubic meter. The foam is greater than 20 percent open cell.

Abstract: An expandable thermoplastic composition is disclosed for extrusion foaming wherein the composition comprises a polyethylene resin; a blowing agent comprising a blend of about 50% by weight of carbon dioxide and about 50% by weight of either normal butane, isobutane, propane, or a mixture of any two or all three hydrocarbons in admixture with the resin in a ratio of about one part blowing agent to about 10 parts resin; zinc oxide nucleation agent in an amount of from about 0.05 to 0.5 kg per 100 kg of the resin; and glycerol monostearate aging modifier in an amount of from about 0.5 to 5 kg per 100 kg of the resin. A process for extrusion foaming of the composition is also disclosed.

Abstract: A process for producing an expandable resin composition for a small diameter electric wire insulated with highly expanded cellular polyethylene which comprises (1) heat-kneading at a temperature higher than 135.degree. C. a mixture comprising: (i) a low density polyethylene having a density ranging from about 0.890 to 0.925 g/ml; (ii) a high density polyethylene having a melting point higher than 130.degree. C.; and (iii) a polyolefin wax having an average molecular weight ranging from about 1500 to 8000 and a melting point ranging from about 100.degree. C. to 160.degree. C.; and (2) heat kneading at a temperature ranging from 120.degree. C. to 130.degree. C. and at a preliminary expansion ratio lower than 5% the mixture of step (1) with a low temperature decomposable chemical blowing agent.

Abstract: Perfluorotripentylamine, perfluoropolyether or another such high-boiling liquid is added as a foaming agent to a thermoplastic fluororesin such as a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin or a tetrafluoroethylene-hexafluoropropylene copolymer resin. Because the vapor pressure of said foaming agent in the molten fluororesin is lower than that of Freon or another such low-boiling foaming agent, the cells in the foam can be made fine and uniform in diameter.

Abstract: Disclosed is a process for obtaining polyester articles, including foamed articles, containing low levels of extractable branching agent. The process comprises: (1) forming a molten mixture comprising (i) a major amount of a first resin composition comprising polyester and from 0 up to about 1 wt. % of a compound capable of branching the polyester, and (ii) a minor amount of a second polyester resin composition comprising at least about 50 wt. % polyester resin and greater than about 2 wt. % of a compound capable of branching the polyester, wherein the relative amounts of (i) and (ii) are such that said molten mixture comprises from about 0.1 wt. % to about 1 wt. % of said branching compound; (2) adding a blowing agent to the molten mixture; and (3) extruding the resultant mixture to obtain a foam. The invention is also directed to the second composition used in the above process, and foamed polyester articles obtained from the process.

Abstract: Disclosed is an ethylenic polymer foam structure comprising an ethylenic polymer material. The ethylenic polymer material contains a substantially linear ethylenic polymer having: a) a melt flow ratio, I.sub.10 I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having about the same I.sub.2 and M.sub.w /M.sub.n. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional stability and foam quality associated with those structures. The foam structures have foam quality similar to those made with conventional LDPE but with enhanced toughness and elasticity. Further disclosed is a process for making the above foam structure and making it in a foam bead form.

Abstract: Foamed propylene polymer articles are prepared by subjecting pre-foamed beads, that consist essentially of propylene polymers having a melt strength from 5 to 40 cN, to thermoforming by sintering.

Abstract: An improved process for production and delivery of a plastisol foam is provided. By the process, plastisol foam is maintained under controlled pressures and conditioned to enhance homogeneity and percent foam. Also provided is a process for intermittently dispensing a fluid such as a plastisol foam, by which drip may be prevented. Additionally provided is novel apparatus for preventing drip.

Abstract: Disclosed is a flexibilized, insulative styrenic polymer foam structure comprising a foam of a polymeric composition of a styrenic polymer greater than 50 percent by weight styrenic monomeric units, the foam having relatively larger primary cells with an average cell size range of about 0.05 to about 1.2 millimeters and relatively smaller secondary cells ranging in cell size from about 5 percent to about 50 percent of the average cell size of the primary cells. The primary and secondary cells constitute at least about 90 percent of the total cell volume within the foam structure. Between 1 and 30 percent by number of the cells have microscopic "pinholes" between them. The presence of the pinholes enhances the flexure of the foam structure. Further disclosed is a method of insulating a surface comprising applying to the surface an insulating panel fashioned from the structure of claim 1.

Abstract: The present invention relates to an improved process for producing, by means of a portable foaming apparatus having a static mixer, a polyurethane foam by reacting a reaction mixture comprised of a polyol, an organic isocyanate, a foaming/frothing agent, and a reaction catalyst, the improvement comprising employing monochlorodifluoromethane as the sole blowing/frothing agent in said reaction in order to produce a CFC-free essentially closed-cell rigid or semi-rigid polyurethane foam. Also claimed is the foam produced by the above process.

Abstract: Foamed propylene polymer articles are prepared by subjecting pre-foamed beads, that consist essentially of propylene polymers having a melt strength from 5 to 40 cN, to thermoforming by sintering.

Abstract: Compositions for producing foamed products which include additives and blowing agents which cause the surface treatment additives to migrate to the surfaces of foamed products. The products produced from the compositions require less additives because the incorporated additives are concentrated at the surfaces thereof.

Abstract: The present invention concerns a process for producing a synthetic resin foam composed of cells having substantially two sizes, one of the sizes being at most 0.3 mm and the other size as being 0.4 to 1 mm, comprising the steps of:forming a mixture of one or more of a water-absorbent high molecular compound, a cell-controlling agent, a synthetic resin, and water; melting the mixture with heating; incorporating a volatile type foaming agent into the mixture under pressure; and extruding the mixture into a lower pressure space to form a foam.

Abstract: An expandable polyolefin composition is disclosed for forming antistatic foam products. The composition includes a polyolefin resin; a hydrocarbyl sulphonate; and an ester of a long-chain fatty acid and polyhydric alcohol. Each of the sulphonate and the ester are present in the composition in an amount sufficient to form a polyolefin product having desirable antistatic properties. A process for extrusion foaming of the composition, and thus formed foam products, are also disclosed.

Abstract: A process for producing structural aromatic polycarbonate thermoplastic foam is provided which involves gas expansion of a melted aromatic polycarbonate thermoplastic resin composition containing an amount of a polytetrafluoroethylene nucleating agent. The thermoplastic resin compositions provided exhibit an improved uniformity of cell structure in the resultant structural thermoplastic foam as a result of the incorporation of the polytetrafluoroethylene nucleating agent. The process and compositions are useful in the production of structural thermoplastic foam articles.

Abstract: A process for producing a biodegradable resin foam, having the steps of mixing a starch polymer containing from 5% by weight to 30% by weight of water, a vinyl alcohol resin containing from 5% by weight to 30% by weight of water, a nonionic surfactant, an inorganic or organic filler, and optionally a thickening agent; optionally adjusting the water content of the mixture, to prepare a composition having from 5% by weight to 30% by weight of water on the whole, based on total weight of the composition; melting and expanding it to prepare a foam, which has a low density and fine closed cells, and shows a good surface condition in a molded body.

Abstract: Process of mixing a fugitive plasticizer, e.g., ethylene carbonate, with moist particulate polyacrylonitrile then removing the water enabling adjustment of the melt viscosity for extrusion of the polyacrylonitrile into film, fiber, pellets and shaped articles. Stretching and heating the extruded polyacrylonitrile film or fiber causes the fugitive plasticizer to exude and vaporize from the film or fiber, carrying with it any remaining acrylonitrile monomer. The resulting film or fiber exhibits substantially increased molecular weight, thus enhancing the tensile strength and barrier properties of the polyacrylonitrile product. The process also produces polyacrylonitrile foam products. A novel cross-linking agent for polyacrylonitrile, divinyloxybutane, is disclosed. Thermostabilizing agents for polyacrylonitrile, N-maleimides and stilbene derivatives, are also disclosed.

Abstract: The present invention relates to a process to produce polystyrene foam comprising mixing a predetermined amount of masterbatch mix and a styrenic polymer, heating this mixture, injecting CO.sub.2 and/or nitrogen, in gas or liquid form, as a blowing agent and subsequently extruding, cooling and drying the resulting polystyrene foam.

Abstract: A thermoplastic molding composition suitable for the preparation of foam is disclosed. The composition comprises a thermoplastic resinous component and a foaming agent which includes A) (i) 0.01 to 4.8% alumina hydrate (aluminum hydroxide) in combination with (ii) 0.01 to 4.8% of an acidic additive or B) 0.01 to 4.8% of the reaction product of said (i) and said (ii), the percentages being relative to the weight of the composition to be foamed. The invention is based on the finding that the foaming of the composition does not lead to any significant reduction in molecular weight of the resinous component or to troublesome discoloration of the foam, even during its re-extrusion.

Abstract: An ultra low density polyolefin foam having a density of about 0.6 to about 1.5 pounds per cubic foot comprising a heat-plastified mixture comprising (1) a non-elastomeric olefin polymer resin selected from the group consisting of ethylene homopolymers, non-elastomeric copolymers of ethylene and a copolymerizable monomer, and propylene homopolymers; (2) an elastomer in an amount of about 3 to about 30 wt. parts per 100 wt. parts of said non-elastomeric olefin polymer resin; (3) polystyrene in an amount of about 1 to about 15 wt. parts per 100 wt. parts of said olefin polymer resin; (4) a stability control agent selected from the group consisting of partial esters of long chain fatty acids with polyols, higher alkyl amines, fatty acid amides, and olefinically unsaturated carboxylic acid copolymers, and (5) a hydrocarbon blowing agent having from 1 to 6 carbon atoms and a boiling point between -175.degree. C. and 50.degree. C.

Abstract: Disclosed is a cross-linked ethylenic polymer foam structure of an ethylenic polymer material of a cross-linked, substantially linear ethylenic polymer. The substantially linear ethylenic polymer having in an uncross-linked state has: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n .gtoreq.(I.sub.10 /I.sub.2)- 4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylenic polymer having about the same I.sub.2 and M.sub.w /M.sub.n. Further disclosed is a process for making the above foam structure.

Abstract: Disclosed is a process for making closed-cell, alkenyl aromatic polymer foam packing bodies. An alkenyl aromatic polymer material is heated to form a melt polymer material. The melt polymer material comprises greater than 50 percent by weight alkenyl aromatic monomeric units. A blowing agent is incorporated into the melt polymer material at an elevated pressure to form a foamable gel. The blowing agent has about 20 weight percent or more based upon the total weight of the first blowing agent selected from the group consisting of carbon dioxide and ethane. The foamable gel is extruded through a die to form a foam strand. The foam strand is pelletized to form a plurality of foam bodies. The bodies are further expanded by exposing them one or more times to heated air or steam. Preferably, the bodies are allowed to age for a preselected period of time after pelletizing and between subsequent expansions.

Abstract: 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.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.

Abstract: The present invention relates to the forming of extruded foam products such as backer rods which are of a cross-linked polyethylene. Disazo condensation color pigments have been found to be particularly suitable as relative fast cross-linking occurs after extrusion. Use of traditional inorganic color pigments substantially impede the cross-linking mechanism. The invention is also directed to a method of forming such cross-linked products.

Abstract: Low density styrene polymer foams having highly desirable physical properties are prepared employing as a blowing agent a mixture of carbon dioxide, lower alcohol and water. The cell size can be effectively controlled by controlling the amount of water in the blowing agent mixture, i.e., small cell or large cell foams can be prepared. A process for preparing such foams is also disclosed.

Abstract: There is disclosed a process for producing alkenyl aromatic foams utilizing a combination of atmospheric and organic gases as blowing agent, preferably using greater than 30% by weight of atmospheric gas, and preferably also using a predetermined about of a masterbatch mix comprising a styrenic polymer, a rubbery block copolymer, and a solid blowing agent. Also disclosed are alkenyl aromatic foams produced by the process which exhibit increased densities, increased thermoforming capabilities, increased post-expansion properties, and increased retainment of the atmospheric and organic gases.

Abstract: The present invention is a styrenic polymer foam blown with solely carbon dioxide and a process for making that styrenic polymer foam. Foam sheet made by this process is especially useful for thermoforming purposes.

Abstract: The present invention relates to an improved process for producing, by means of a portable foaming apparatus having a static mixer, a polyurethane foam by reacting a reaction mixture comprised of a polyol, an organic isocyanate, a foaming/frothing agent, and a reaction catalyst, the improvement comprising employing monochlorodifluoromethane as the sole blowing/frothing agent in said reaction in order to produce a CFC-free essentially closed-cell rigid or semi-rigid polyurethane foam. Also claimed is the foam produced by the above process.

Abstract: The invention relates to a breathable, plastic film, useful as a wall covering material. A low boiling additive, such as water, is added to a plastisol before extrusion. During extrusion and curing of the plastisol into a film or coating, the low boiling additive is volatilized and the resulting evolved gas perforates the forming film. In this manner a permeable plastic film, such as vinyl, is produced.

Abstract: The invention relates to expandable styrene polymers containinga) a styrene polymer,b) and at least one carbon dioxide absorber, mixed or copolymerized with the above, in an amount of from 0.01 to 50% by weight, based on the sum of a) and b), andc) a blowing agent or blowing agent mixture in an amount of from 0.5 to 12% by weight,where the blowing agent or blowing agent mixture comprisesc.sub.1) from 10 to 100% by weight of carbon dioxide andc.sub.2) from 0 to 90% by weight of at least one further blowing agent.The invention furthermore relates to the styrene polymers containing a carbon dioxide absorber, to the styrene polymer foams obtainable from the expandable styrene polymers, and to an improved process for impregnating styrene polymers with carbon dioxide-containing blowing agents or blowing agent mixtures.

Abstract: Improved microcellular and ultramicrocellular materials containing hydrofluorocarbon (HFC) inflatants are disclosed. The inflatants are environmentally more favorable than fully halogenated chlorofluorocarbons (CFCs).

Abstract: Films of thermoplastic polyurethanes (TPU) with a Shore hardness of 75 A to 92 A having 5 to 20% by weight of polyether amide block copolymers and/or polyether ester block copolymers, and their use for adhering to other substrates, particularly for back-foaming with polyurethane foam. The invention also relates to the use of an addition of 5 to 20% by weight of polyether amide block copolymers and/or polyether ester block copolymers to thermoplastic polyurethanes with Shore hardnesses of 75 A to 92 A, based on the weight of the thermoplastic polyurethanes, for decreasing the adhesion and/or interlocking of thermoplastic polyurethanes produced by single layer blown extrusion technique.

Abstract: The present invention is a styrenic polymer foam blown with solely carbon dioxide and a process for making that styrenic polymer foam. Foam sheet made by this process is especially useful for thermoforming purposes.

Abstract: Method and apparatus for producing a molded article of a foamed thermoplastic resin and articles produced thereby. A molten mass of an expandable thermoplastic resin is accumulated in an accumulator while it is prevented from foaming. A quantity of the accumulated foamable melt is extruded through a die orifice having a shape adapted to reflect the shape of the desire finished product. The extruded foamable melt commences foaming as it comes in contact with the atmosphere. As the extruded thermoplastic resin foams, it is pulled vertically downward from the die orifice by gravity. The downward-hanging, foamed, thermoplastic material is captured between the halves of a vertically-oriented mold before the foaming expansion of the foamable melt has been completed. The foamed thermoplastic material is compressed by the vertically-oriented mold into the desired shape.

Abstract: Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material: b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel: c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die: and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.

Abstract: Low density styrene polymer foams having highly desirable physical properties are prepared employing as a blowing agent a mixture of carbon dioxide, lower alcohol and water. The cell size can be effectively controlled by controlling the amount of water in the blowing agent mixture, i.e., small cell or large cell foams can be prepared. A process for preparing such foams is also disclosed.