Abstract: Foamed thermoplastic polymeric mechanical planarization polishing pads (“MP pads”) made with supercritical fluids are presented. A supercritical fluid foaming agent is dissolved in a thermoplastic polymer. A rapid change in the solubility and volume of the supercritical fluid foaming agent in the thermoplastic polymer results in foaming of the thermoplastic polymer. Foamed thermoplastic polymeric MP pads are advantageously both significantly and uniformly porous.

Abstract: U.S. Pat. No. 6,232,354 issued May 15, 2001 describes an environmentally friendly and commercially practicable process for the production of microcellular polymer foams from amorphous, semi-crystalline and crystalline polymers which involves consolidating the polymer, saturating the polymer with an inert gas at elevated temperature and under elevated pressure, and controllably cooling, i.e. quenching the saturated polymer under a variety of temperature and pressure conditions to produce either a closed or open celled microcellular foam or a high density microcellular foam. It has now been discovered that a process similar to that described in this patent can be used for the production of nanocomposite and molecular-composite foams that exhibit exceptional physical properties.

Abstract: A process for injection-foaming a thermoplastic resin by using an injection molding machine with a two-stage-compression screw, injecting a physical foaming agent into the cylinder of the machine at a pressure lower than the storage pressure of the physical foaming agent, mixing it with a melted resin and expanding the volume of the cavity of the mold at the time of injection, and an injection molding machine and resin composition suitable therefore.

Abstract: This invention relates to compositions of cyclopentane, and a compound selected from the group consisting of hydrofluorocarbons, hydrofluoroethers, or fluorinated sulfur compounds. Specifically these compounds may be selected from the group consisting of tetrafluoroethane, hexafluoropropane, pentafluoropropane, tetrafluoropropane, trifluoropropane, difluoropropane, octafluorobutane, hexafluorobutane, pentafluorobutane, nonafluorobutane, difluorobutane, trifluoro-2-methoxyethane and bis(pentafluoroethyl)sulfide. The compositions, which may be azeotropic or azeotrope-like, may be used as refrigerants, cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, refrigerants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents or displacement drying agents.

Abstract: The present invention provides blowing agent introduction systems and methods for introducing blowing agent into polymeric foam processing systems. The methods may involve introducing one or more doses of blowing agent into polymeric material in an extruder during a plastication period of a molding cycle. Prior to introduction, a dose is confined in an accumulator which, for example, has a volume defined between an inlet valve and an outlet valve. A control system may receive inputs related to system parameters (e.g., pressure of polymeric material in extruder, axial position of screw in barrel, whether screw is rotating, and the like) and based on the inputs coordinates operation of the valves to confine and introduce the blowing agent dose(s). The introduction systems may be used in discontinuous plasticating processes, such as injection molding and blow molding, and can be particularly useful in processes that use precise quantities of blowing agent.

Abstract: It is an object of the present invention to provide a method for manufacturing a high-quality foam that can be produced stably on an industrial scale and that affords excellent thermal insulation as a foam with thin cell membranes, which method ensures uniform molten mixture fluidity, which is an essential condition for achieving consistent foam quality, in the manufacture of a foam by mixing starch as one molten polymer compound with another polymer compound having a different melt viscosity, and to provide a foam manufactured by this method. Water is added to and mixed with a plant-derived fibrous material and starch to manufacture a foam of a plastic resin containing as compositional components starch and a plant-derived fibrous material such as pulverized paper, pulverized wood, or the like.

Abstract: A lightweight member is provided for reinforcing, sealing or baffling structures of articles of manufacture such as automotive vehicles. The lightweight member preferably includes a carrier member having a cellular structure and an expandable material disposed thereon.

Abstract: A foaming agent charging and mixing device comprises at least one mixing device and one foaming agent metering device, wherein the foaming agent charging and mixing device may be arranged between an plasticating screw and a mold. In order to improve the foaming agent charging and mixing device in a manner that the mixing with foaming agent is facilitated and at the same time a risk of obstruction of the foaming agent metering device is avoided, the foaming agent metering device is alternately opened and closed through the mixing device during operation thereof for supplying foaming agent to the plastic melting.

Abstract: An indirect solid free form scaffold manufacturing technique is provided. More particularly, the present invention provides a set of molds, casting methods, mold removals, and surface modification techniques that are compatible with image-based design methods and with solvent, melt, and slurry casting of polymers and ceramics.

Abstract: An apparatus for supplying a resin material to an injection molder comprises a vessel for storing a resin material, gas supplying means for supplying an inert gas to the vessel which is not a super-critical state, and material supplying means for supplying the resin material from the vessel to an injection molder.

Abstract: The invention relates to a process for producing foam webs by foam extrusion of a mixture of a polysulfone or polyether sulfone and a volatile blowing agent, where the blowing agent is water or a mixture of water with an inert gas or organic liquid, e.g. an alcohol or a ketone.

Abstract: A method for production of an extruded, polystyrene-based foam plate wherein a polystyrene-based resin is heated and kneaded together with a blowing agent, a flame retardant and a nucleating agent in an extruder to obtain a foamable molten composition, and the foamable molten composition is extruded through a die attached to an end of the extruder into a lower pressure zone. The blowing agent comprises not smaller than 25% by weight but not greater than 65% by weight, based on the total weight of the blowing agent, of an isobutane-containing saturated hydrocarbon; not smaller than 5% by weight but not greater than 70% by weight, based on the total weight of the blowing agent, of a dimethyl ether-containing ether; not smaller than 5% by weight but not greater than 55% by weight, based on the total weight of the blowing agent, of carbon dioxide; and 0–25% by weight, based on the total weight of the blowing agent, of other blowing agent components.

Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.

Abstract: A process for producing physically foamed injection molded articles is provided. The process involves feeding a propellant-free thermoplastic melt into a cavity followed by delivering a physical propellant directly into the cavity or directly into the melt flowing into the cavity. The pressure exerted on the propellant during the injection stage is greater than that exerted on the propellant during the holding phase.

Abstract: Expanded, substantially non-crosslinked polypropylene resin beads capable of producing a high rigidity foamed molding at a relatively low temperature. The beads are produced by a process including a step of dispersing substantially non-crosslinked polypropylene resin particles in a dispersing medium containing an organic peroxide to obtain a dispersion, a step of heating the dispersion to decompose the organic peroxide and to modify the surface of the surface-modified polypropylene resin particles, and a step of expanding the non-crosslinked, surface-modified polypropylene resin particles using a blowing agent.

Abstract: Provided are compositions comprising HFC-245fa and trans-1,2-dichloroethylene which exhibit relatively high solubility with conventional hydrocarbon lubricants, non-flammability, and relatively constant boiling points. Also provided are uses of such compositions.

Abstract: Continuous polymeric extrusion nucleation systems and methods useful for making polymeric microcellular foamed materials, including crystalline and semi-crystalline polymeric microcellular materials, are provided. Pressure drop rate is an important feature in some embodiments, and the invention provides systems for controlling these and other parameters. One aspect involves a multiple-pathway nucleator that is separated from a shaping die by a residence chamber. Another aspect involves a die for making advantageously thick articles, including a multiple-pathway nucleation section. Microcellular material can be continuously extruded onto wire, resulting in a very thin, essentially closed-cell microcellular insulating coating secured to a wire. Other very thin microcellular products can be fabricated as well.

Abstract: Injection molding systems and methods useful for making microcellular foamed materials are provided as well as microcellular articles. Pressure drop rate and shear rate are important features in some embodiments, and the invention provides systems for controlling these parameters in an injection molding system. Another aspect involves an injection molding system including a nucleator that is upstream of a pressurized mold. Another aspect involves an extrusion system with the reciprocating screw for forming a single phase solution of non-nucleated blowing agent and polymeric material. Another aspect involves very thin walled microcellular material and very thin walled polymeric material. Another aspect provides a method for producing high weight reductions in very thin-walled parts with surfaces that have no noticeable differences from non-foamed parts.

Abstract: Process for manufacturing molded articles made of plastics, cellulose, pulp or wood fibers with cavities, in particular composite parts for light weight construction, by means of tool parts, including the following process steps: a) matrix layer is provided at pre-selected locations with inserts containing gas-creating substances or blowing agents and b) these inserts are activated to create gas in tool parts and thus expand the matrix material. Also disclosed are gas-creating insertion elements for use in the process and made of gas-creating blowing substances enclosed in gas-proof sheaths or inserted into the matrix material in order to form locally limited areas. This process allows the production of particularly light and at the same time solid tool parts, in particular composite parts for light-weight construction.

Abstract: A method for making a resilient material includes providing a particulate polymer, discrete pieces of foam, a foaming agent and a plasticizer. The polymer, foam pieces and plasticizer are mixed and disposed in a mold. The mold is heated to cause melting of the polymer without melting of the foam. After coating of the melted polymer, a heterogeneous resilient cushion is formed with gelated polymer surrounding the discrete foam pieces.

Abstract: The invention provides a method for producing a foamed article comprising the steps of: heating a mixture comprising (a) 100 parts by weight of linear saturated polyester, (b) 0.1 to 10 parts by weight of a mixture as a coupling agent of 0 to 100% by weight of a compound having two epoxy groups in the molecule, and 100 to 0% by weight of a compound having two or more epoxy groups, and (c) 0.01 to 5 parts by weight of a metal salt of a carboxylic acid as a coupling reaction catalyst, at a temperature of a melting point of the polyester or more to provide a melt flow rate of 50 g/10 minutes or less and swell of 10 to 200%, whereby a polyester resin is formed; and heating and foaming the polyester resin using a foaming agent .

Abstract: An extruded styrene resin foam which is produced by using a blowing agent imposing a reduced load on the environment and has outstandingly excellent thermal insulating property and flame retardant property adapted for construction use.

Abstract: A method for producing expanded polypropylene resin particles wherein polypropylene resin particles impregnated with a physical blowing agent are heated along with an aqueous medium and a dispersant and are released and expanded at reduced pressure from the interior of a pressure-tight vessel, wherein the aforementioned aqueous medium has an electrical conductivity of from not less than 0.00 ms/m to not more than 20.00 mS/m. The resulting particles obtained are without inconsistencies caused by differences in the amount of dispersant adhering to the particles or the amount of dispersant added to prevent the particles from fusing together during the heat treatment step of the method.

Abstract: The object of the present invention is to provide a plastic molded material having uniform foamed structure at a low price. To attain said object, a method comprising; mixing particle containing 30 to 70% by weight of water in thermoplastic resin, heating and melting said thermoplastic resin in which said particles containing water are mixed under a high pressure, releasing said high pressure to form foamed structure and cooling to solidify said foamed thermoplastic resin.

Abstract: The invention relates to an improved method for producing foamed material, especially poly(meth)acrylimide foams, which are foamed from polymer plates produced according to the casting method. The two-step method consists of a pre-heating step and at least one foaming step. The product obtained has a significantly smaller compressive strain, measured according to DIN 53425(ASMD 621), than prior art products.

Abstract: Manufacture of molded polyurethane or molded polyurethane containing products, especially thermoplastic products, such as elastomers, flexible foam, and rigid foam using gas assisted injection molding. Preferred polyurethane products are thermoplastic polyurethanes.

Abstract: A process for producing a polymer/filler composite material includes a mixture forming step in which there is obtained a mixture of a flake-like filler and a polymer material, and the mean area (L2), mean thickness (d) and volume fraction (c) of the flake-like filler in the mixture satisfy the following equations (1), (2) and (3): 500 nm2≦L2≦100 &mgr;m2  (1) d≦L/20  (2) 0.2d/L≦c≦4d/L  (3), and a deforming step of applying deformation to the mixture at a strain rate of no greater than 10 s−1.

Abstract: In a method for forming a micro-pattern on a substrate (200), polymer material having a solvent is coated on the substrate, thereby forming a polymer film on the substrate. Then, a mold (204) having a predetermined shape is compressed into the polymer film (202) on the substrate by employing a predetermined compression technique to entail a plastic deformation of the polymer film, thereby patterning the polymer film. This compression procedure is performed at a room temperature, e.g., of about 10 to about 30° C. In the present invention, before the mold (204) is pressed into the polymer film (202), a free volume in the polymer film is previously increased so that a pressure applied on the polymer material needed to plastically deform the polymer film is reduced. Thereafter, etching is performed on the substrate through the use of the patterned polymer film as an etching mask, thereby forming a micro-pattern on the substrate.

Abstract: Non-flying plastic microballoons are produced by bringing unexpanded, expandable plastic microballoons, which have been heated to a temperature lower than an expansion starting temperature thereof, and a mixture of a wetting agent and gas, the mixture having been heated to a temperature at least equal to the expansion starting temperature of the expandable plastic microballoons, into contact with each other to cause expansion of the expandable plastic balloons, and then cooling the resulting expanded plastic balloons.

Abstract: Apparatus and method for the production of expandable plastics granulate (C). A plastics melt (A′) is impregnated by a fluid blowing agent (B), which is, at an elevated pressure within a predetermined pressure range, only partly soluble in the melt. The method comprises the following steps: 1. dispersion of the blowing agent in the melt, 2. retaining of the mixture within a predetermined pressure range for a predetermined retention time, 3. cooling of the melt impregnated by the blowing agent to a temperature which is several degrees Celsius above the solidification temperature of the melt, and 4. granulating the cooled mixture.

Abstract: A process for injection-foaming a thermoplastic resin by using an injection molding machine with a two-stage-compression screw, injecting a physical foaming agent into the cylinder of the machine at a pressure lower than the storage pressure of the physical foaming agent, mixing it with a melted resin and expanding the volume of the cavity of the mold at the time of injection, and an injection molding machine and resin composition suitable therefore.

Abstract: A manufacturing method for a synthetic leather includes a first step of feeding materials of preset volume, a second step of materials foaming (capable to be skipped if unnecessary), a third step of material and mixing injecting to produce liquid mixed materials by instant reaction, a fourth step of conveying two basic cloths, a fifth step of compressing the two basic cloths with the liquid mixed materials producing reaction between the two basic cloths conveyed to an upper portion of two rollers to produce synthetic leather, and a sixth step of winding finished synthetic leather on two winding wheels.

Abstract: According to this invention, thermal expansion microcapsules can be substantially evenly mixed with a base resin and an expected expansion coefficient for the thermal expansion microcapsules can be obtained during resin molding in a mold. Specifically, this invention provides a method for manufacturing a synthetic resin molding using thermal expansion microcapsules in which the thermal expansion microcapsules are mixed with a base resin and the mixture undergoes resin molding in a mold, wherein the thermal expansion microcapsules are granulated with a given binder resin under a temperature condition in which the thermal expansion microcapsules are not thermally expanded; then the mixture is mixed with the base resin; and the mixture undergoes resin molding.

Abstract: A release-controlled pipe and a related manufacturing method comprise several main steps, which are mixing a formulation, first hot melt extrusion and cooling, grinding into pieces, second hot melt extrusion, molding and cooling. The present invention includes the steps of first mixing elastomer pellets and a binder, then pouring the formulation into a melt extruder for extruding and shaping a rod-like extrudate. Then the rod-like extrudate is ground into pieces and placed into a water-filled container and another dry container. The mixture of dry ground pellets, wet ground pellets including water, and a small amount of lubricant is poured into a melt extruder for extruding, and a release-controlled pipe is shaped via a pipe die head and gathered by a winder after cooling.

Abstract: A method for manufacturing opened-cell plastic foams includes a plurality of steps including a step of mixing ethylene vinyl acetate copolymer (EVA) or polyethylene resins (PE), a preset percentage of a blowing agent and a vulcanizing agent, pigment, aids agent, and hollow porcelain balls or hollow micro grains evenly, a step of placing the mixed material in a mold to proceed batch-foaming once or twice. And a step of opening the mold for instant foaming process can let a solid shell of the mixed material with porous chamber structure produce ruptured holes so that the finished product of plastic foams may have good airiness and soft flexibility.

Abstract: A plastic foamed synthetic closure for use with liquid bearing containers which closely simulates natural cork products is realized by incorporating color concentrates into the polymer melt and forming the color concentrates into elongated streaks. The desired emulation is further enhanced by arcuately pivoting the foamed plastic material during the production to form curved or sinusoidal-shaped streaks. This invention also provides manufacturing methods for mass producing individual products in a continuous motion casting system wherein fully complete products are formed in polymer casting members, which receive foam material exiting from the die and allow the foamed material to be formed in a continuous operation in the casting members. Finally, the present invention also teaches a unique system for maintaining and delivering carbon dioxide in its supercritical phase for use as a blowing agent.

Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.

Abstract: The biodegradable acting material is made from starch with various additives such as nucleators and plasticizer. The blowing agent used for foaming of the starch material may be alcohol or water. The material is made by mixing a charge of starch, nucleator and plasticizer to form a flowable mass which is then injected on the fly with the blowing agent, i.e. alcohol and/or water. Thereafter, the flowable mass is extruded through a dye and is either cooled to form a latent-foaming material or is allowed to expand into a foamed state. The starch which is used may be a corn starch, potato starch or the like.

Abstract: A method and apparatus for making a densified skin polymer foam plank comprising providing a polymer foam having a plurality of cells and heating an outer surface of the foam at a heating station. The heating step collapses and melts the cells adjacent the outer surface to form the densified skin having a density greater than a density of the foam before the heating step. Additionally, the method and apparatus may further include extruding the polymer foam from an extruder.

Abstract: Production of extruded styrene resin foams which are excellent in environmental compatibility and retain highly efficient thermal insulation property and have appropriate strength properties is disclosed which is characterized by using as a blowing agent a blowing agent comprising mainly 40% by weight or more and 85% by weight or less, based on the whole amount of the blowing agent, of at least one ether selected from the group consisting of dimethyl ether, methyl ethyl ether and diethyl ether, and 15% by weight or more and 60% by weight or less, based on the whole amount of the blowing agent, of at least one saturated hydrocarbon selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms. The production is further characterized by providing a more desirable cell structure such as a specified shape of cells or the presence of larger and smaller cells.

Abstract: This invention relates to compositions of cyclopentane, and a compound selected from the group consisting of hydrofluorocarbons, hydrofluoroethers, or fluorinated sulfur compounds. Specifically these compounds may be selected from the group consisting of tetrafluoroethane, hexafluoropropane, pentafluoropropane, tetrafluoropropane, trifluoropropane, difluoropropane, octafluorobutane, hexafluorobutane, pentafluorobutane, nonafluorobutane, difluorobutane, trifluoro-2-methoxyethane and bis(pentafluoroethyl)sulfide. The compositions, which may be azeotropic or azeotrope-like, may be used as refrigerants, cleaning agents, expansion agents for polyolefins and polyurethanes, aerosol propellants, refrigerants, heat transfer media, gaseous dielectrics, fire extinguishing agents, power cycle working fluids, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents or displacement drying agents.

Abstract: A process is described for producing foam materials from two-component reactive plastics using carbon dioxide as blowing agent by mixing at least one of the reactive components with carbon dioxide under pressure, mixing the components, at least one of which contains carbon dioxide under pressure, expanding the reactive mixture containing carbon dioxide obtained by mixing, and hardening, wherein the expansion takes place suddenly with the production of high rates of shear. Preferably the rate of flow of the reaction mixture is reduced after expansion.

Abstract: A method for manufacturing a PU (polyurethane) polishing pad is provided. Resins containing active hydrogen functional groups such as polyol resins, polyamine resins, and polythiol resins, and polyisocyanate resins containing —NCO functional groups are mixed to form a foamed PU polishing pad with excellent polishing properties by reaction injection-molding under high pressure, low temperature and auxiliary gas-adding. The PU polishing pad in accompany with an abrasive slurry can be widely used to polish high-level products such as wafers and optical glass.

Abstract: In a process for forming low-density foamed articles, a blend of foamable thermoplastic material and physical foaming agent concentrate is mixed and melted and expanded to form an extruded foam article.

Abstract: A method of making a porous biodegradable polymer is disclosed, which comprises (a) placing a biodegradable polymer and a solvent in a chamber; (b) adding a supercritical fluid to the chamber and maintaining the chamber at a predetermined temperature for a sufficient period of time to allow the supercritical fluid to dissolve into the biodegradable polymer with the help of the solvent; and (c) venting the supercritical fluid and the solvent by reducing the pressure in the chamber, thereby obtaining a porous biodegradable polymer.

Abstract: Nano-sized particles such as nano-clays can be mixed with polymers through either melt compounding or in-situ polymerization. By modifying the particle surface with various surfactants and controlling processing conditions, we are able to achieve either intercalated (partial dispersion) or exfoliated (full dispersion) nano-clay distribution in polymers with the clay content up to 35% by weight. When a blowing agent is injected into the nanocomposite in an extruder (a continuous mixer) or a batch mixer, polymeric foam can be produced. Supercritical carbon dioxide, an environmentally friendly, low-cost, non-flammable, chemically benign gas is used as the blowing agent. This process forms a microcellular foam with very high cell density (>109 cells/cc) and small cell size (<5 microns) can be achieved by controlling the CO2 content, melt and die temperature, and pressure drop rate.

Abstract: The invention relates to a method for manufacturing molded bodies having a blown, foamy structure, wherein a mass (S) comprising a suspension of at least starch, starch derivatives or mixtures thereof in water, is pressurized in or through a mold (23) and the mass (S) heated in the mold (23) in a manner such as to give rise to at least cross-linking of the starch, the starch derivatives or the mixture thereof wherein the mass (S) in the mold (23) is brought at least to the baking temperature, wherein the suspension is at least partially prepared from vegetable material which has not been subjected to an artificial drying step and which, calculated on the dry substance, contains at least 50 wt. % of starch, said vegetable material at least being ground to particles of a suspendable size. The invention further relates to the use of ground vegetable material, which vegetable material has not been subjected to an artificial drying step and, calculated on the dry substance, contains at least 50 wt.

Abstract: The present invention generally relates to processes for preparing extruded foam products and more particularly to a process for producing such products wherein surface defects are minimized. There has been a movement to replace conventional halo-carbon blowing agents in favor of purportedly more environmentally safe halo-carbon free blowing agents such as carbon dioxide, nitrogen, argon, water, air, nitrogen, and helium. However, these halo-carbon free blowing agents, in particular carbon dioxide, have higher foaming rates and higher volatility leading to greater surface defects in the extruded foam. The present invention employs polyethylene wax to reduce or eliminate the occurrence of surface defects where halo-carbon free blowing agents are employed in an extruded foam manufacture process.

Abstract: A method of molding components of a shopping cart using high or low pressure molding processes. The molding processes eliminate sink marks in plastic components of the shopping cart while providing structural integrity thereto. The processes used to mold the components of the shopping cart can create either or both a center channel in the molded components and/or a plurality of voids within the molded components. If hollow channels are formed in the molded components then the plurality of voids will be formed in the walls of such molded component if both processes are used together. The processes used to form the molded components are either (i) a gas assist process which provides a laminar stream of blowing agent into the stream of molten resin after the molten resin is forced into a partially filled mold or (ii) a structural foam molding process which provides a blowing agent blended into the molten resin prior to the molten resin being forced into the mold.

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.