Abstract: The present invention pertains to improved alkenyl aromatic polymer foams (and processes for their preparation) having increased heat distortion temperature and improved dimensional stability while maintaining good tensile/tear, creep and environmental dimensional change properties.The closed cell low density alkenyl aromatic polymer foams exhibit increased heat distortion temperature, when substantially random interpolymers of about 21 to about 65 mol % styrene are blended in. When these same alkenyl aromatic polymer foams are made without these interpolymers, the heat distortion temperature is not improved.

Abstract: A water vapor permeable, waterproof polyether ester membrane contains 1 to 10% by weight of finely dispersed carbon particles, especially soot particles, having an average size of 5 to 40 nm.

Abstract: Disclosed is a process for the production of an injection-expansion molded, thermoplastic resin product. The process comprises a gas dissolving step, a cooling step, a metering and injection step, and an expansion controlling step. Specifically, a thermoplastic resin is molten in a continuous plasticator (1), supercritical carbon dioxide and/or nitrogen is added as a blowing agent, and the blowing agent and the thermoplastic resin are formed into a mutually-dissolved state. The resultant molten resin composition is cooled within the plasticator while maintaining a pressure equal to or higher than a critical pressure of the blowing agent. The thus-cooled molten resin composition is metered by an injector (7) and is filled in a mold (8). An internal pressure of the mold is lowered beyond the critical pressure of the blowing agent to produce cell nuclei, whereby the cell diameter is controlled. The blowing agent is maintained in a supercritical state up to the metering and injection step.

Abstract: A water vapor permeable, waterproof polyether ester membrane contains 1 to 10% by weight of finely dispersed carbon particles, especially soot particles, having an average size of 5 to 40 nm.

Abstract: The invention relates to a process for preparing expanded articles based on ethylene-chlorotrifluoroethylene copolymers having high dielectric characteristics consisting in mixing the copolymer with 0.5-2% by weight of boron nitride, extruding the blend at 260.degree.-300.degree. C., injecting into the molten blend nitrogen at 50-150 atmospheres and lowering the pressure for obtaining the expanded article.

Abstract: A process for preparing an expanded product of a thermoplastic resin which includes a gas dissolving step of adding supercritical carbon dioxide and/or nitrogen as an blowing agent to a thermoplastic resin, and melting it in the thermoplastic resin, a cooling step of cooling the resulting molten resin composition under a pressure not less than a critical pressure of the blowing agent, a nuclei forming step of discharging the molten resin composition from a die to lower the pressure to a level not more than the critical pressure, and an expansion controlling step of cooling an expanded product of the thermoplastic resin to a level not more than a glass transition temperature or a crystallization temperature of the resin to control a cell diameter of the expanded product.

Abstract: The present invention provides a method for the semi-continuous production of microcellular foam articles. In a preferred embodiment, a roll of polymer sheet is provided with a gas channelling means interleaved between the layers of polymer. The roll is exposed to a non-reacting gas at elevated pressure for a period of time sufficient to achieve a desired concentration of gas within the polymer. The saturated polymer sheet is then separated from the gas channelling means and bubble nucleation and growth is initiated by heating the polymer sheet. After foaming, bubble nucleation and growth is quenched by cooling the foamed polymer sheet.

Abstract: Disclosed is an evacuated and unevacuated microcellular foam containing an infrared attenuating agent (IAA). The evacuated foam has an average cell size of about 70 micrometers or less. The unevacuated foam has an average cell size of 1.0 micrometers or less. The IAA provide a greater proportional reduction in foam thermal conductivity in these foams than in foams of larger cell size. Further disclosed is a method of using the foams.

Abstract: An elongated member, for example, a bowling pin, has a core of foamed plastic material, which has areas of greater density, generally toward the lower end of the bowling pin, so as to provide desired weight distribution along the member. In the bowling pin, providing a denser core area near the bottom lowers the center of gravity. In a baseball bat, the increased density can be provided in the "sweet spot" area, if desired.In producing the variation in density, the mold in which the foamed core is formed is heated in those areas in which the density is to be light and chilled in those areas in which the density is to be increased.In making a baseball or softball bat, a foamed core can be wrapped directly with graphite filament or graphite and glass filaments, or synthetic fibers such as Aramid fibers of the type marketed by Dupont de Nemours as KEVLAR.RTM. either dry wrapped and subsequently embedded in epoxy or the like, or wrapped with adhesive coated fiber that is then cured.

Abstract: Disclosed is a method for providing accelerated release of a blowing agent from a solid, non-perforated plastic foam. The method relates (a) providing the solid, non-perforated plastic foam having the blowing agent and a permeability modifier therein and (b) perforating the foam at its surface to form a multiplicity of channels extending from the surface into the foam. The channels are in gaseous communication with the environment outside the foam and provide accelerated release of blowing agent.

Abstract: A process for making a closed-cell, alkenyl aromatic polymer foam structure having enlarged cell size. An alkenyl aromatic polymer material is heated to form a melt polymer material. An amount of a non-waxy cell size enlarging agent is incorporated into the melt polymer material. The enlarging agent is present in an amount sufficient to enlarge the stabilized cell size of the formed foam structure by 20 percent or more over a corresponding foam structure made without the enlarging agent. Further, the enlarging agent is incorporated in a quantity such that the formed foam structure has physical properties substantially the same degree as the corresponding foam structure. A blowing agent is incorporated into the melt polymer material at an elevated pressure to form a foamable gel. The foamable gel is expanded in a zone of lower pressure to form the foam structure. Further, disclosed is a foam structure corresponding to the above.

Abstract: Disclosed is a method for providing accelerated release of a flammable blowing agent from a plastic foam. The method comprises (a) providing the plastic foam having the blowing agent and a permeability modifier therein and (b) perforating the foam at its surface to form a multiplicity of channels extending from the surface into the foam. The channels are in gaseous communication with the environment outside the foam structures and provide accelerated released of blowing agent.

Abstract: A method of controlling the nucleation of cells in a polymeric foam material includes blending a matrix material with a second phase material which provides sites for bubble nucleation. The selection of the second phase material controls the size and density of the cells.

Abstract: A process for producing a porous pipe is disclosed and includes forming an extrudable mixture comprising elastomer particles, binder component and a solid water carrier component having a composition other than the elastomer particles and the binder component and being associated with sufficient water to provide porosity to a porous pipe produced from the mixture; and extruding the extrudable mixture to conditions effective to form the porous pipe.

Abstract: A supermicrocellular foamed material and a method for producing such material, the material to be foamed such as a polymerplastic material, having a supercritical fluid, such as carbon dioxide in its supercritical state, introduced into the material to form a foamed fluid/material system having a plurality of cells distributed substantially throughout the material. Cell densities lying in a range from about 10.sup.9 to about 10.sup.15 per cubic centimeter of the material can be achieved with the average cell sizes being at least less than 2.0 microns and preferably in a range from about 0.1 micron to about 1.0 micron.

Abstract: A method for producing a filter for use in a fuel flow rate regulating mechanism has a first step of providing a sheet of microcellular polymer material having upper and lower surfaces, each of the surfaces being fused to prevent fuel flow through the surfaces. The sheet of microcellular polymer material also has formations of continuous air bubbles between the upper and lower surfaces. The method for producing a filter has a second step of heat pressing in the direction of thickness to rearrange certain of the air bubbles, redefining same as independent, nonconnected air bubbles. The method for producing a filter has a third step of transversely punching from the sheet a filter element of prescribed configurations.

Abstract: Disclosed is a bimodal, insulative, styrenic polymer foam structure comprising a foam of a styrene polymer material of greater than 50 percent by weight of styrenic monomeric units, the foam having relatively larger primary cells with a cell size range of 0.05 to 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. The bimodal structure has an amount of carbon black sufficient to reduce the thermal conductivity of the structure below that of a corresponding bimodal structure without carbon black. Further disclosed is a process for making the foam structure.

Abstract: A method for producing microcellular foam from a semi-crystalline polymeric material. The material is heated to its melting point at an elevated pressure and then saturated with a uniform concentration of a gas. The pressure is then lowered causing bubble nucleation and growth within the material. The material is then quenched to prevent further foaming. Bubbles on the order of 5 .mu.m in diameter are produced with a bubble density of approximately 10.sup.10 bubbles/cm.sup.3.

Abstract: Foam thermoplastic injection molding apparatus and method produces structurally superior foam injection molded products. The process includes plasticating solid polymer to a polymer melt; accumulating the melt in an accumulator having a telescoping inlet, which allows the first melt which enters to be the first to leave the accumulator; combining a preselected amount of melt with a preselected amount of gas in bubble form to form homogenized polymer foam; shearing the homogenized polymer foam to reduce the size of gas bubbles; and injecting the polymer foam through a special gate assembly into a mold. The gate assembly has a removable nose which remains with the mold, allowing the foam to expand within the mold but not allowing the foam to escape the mold. The process and apparatus allow low molded-in stress products to be produced, and can process recyclable thermoplastics, either single materials or mixtures. Thus, no segregation of materials is required.

Abstract: A thermoplastic plastic granule having an expansion agent uniformly distributed within a plastic polymer-matrix and, containing additionally a cell-forming agent in a finely and uniformly distributed manner. Such thermoplastic granules are used for producing foamed molded bodies in a mold.

Abstract: This invention relates to the use of a special class of sulfonic and phosphonic acids, and salts of the acids, to give improved nucleation for foam extrusion of thermoplastics using either dissolved gas or chemical blowing agents to produce foam.

Abstract: This invention relates to the use of a special class of sulfonic and phosphonic acids, and salts of the acids, to give improved nucleation for foam extrusion of thermoplastics using either dissolved gas or chemical blowing agents to produce foam.

Abstract: A foamed and expanded low density polyethylene sheet or tube possesses both superior buoyancy and thermal resistance characteristics. The sheet or tube is made by a process including mixing a low density polyethylene with a blowing agent, surface activation agent and, preferably, a separation agent, heating the mixture at different temperatures to first melt the mixture and then gasify the blowing agent to expand the polyethylene cells, cooling the melted mass to partially harden and shrink the expanded cells, further expanding the cells by introducing a second gaseous blowing agent, cutting, extruding and cooling the expanded mass, forming a sheet or tube from the cooling mass, and finally cooling the sheet or tube for at least 24 hours. A buoyant, thermal resistant, water-repellent and moisture resistant sheet or tube results, which can be used, for example, as a liner for garments, including sports, business and military garments and other related equipment.

Abstract: Prefoamed particles of a polyolefin resin are produced by dispersing starting particles of the polyolefin resin, which contains a volatile foaming agent, in a dispersant in a pressure vessel, heating the resultant dispersion to a temperature of at least the softening point of the starting particles in said pressure vessel and then opening the vessel at one end thereof so as to release the starting particles and dispersant into an atmosphere of a pressure lower than the internal pressure of the vessel. The release of the starting particles and dispersant is performed while feeding a heating liquid.

Abstract: This invention relates to the use of a special class of sulfonic and phosphonic acids, and salts of the acids, to give improved nucleation for foam extrusion of thermoplastics using either dissolved gas or chemical blowing agents to produce foam.

Abstract: Porous membranes are produced by dissolving a film-forming polymer in a good solvent for the polymer, forming a film of the resulting polymer solution, and forcibly contacting saturated steam or mist-containing steam with at least one surface of said film. Such porous membranes have pores having a narrow pore diameter distribution and extending in a direction substantially perpendicular to the membrane surface at a high surface pore density on at least one surface thereof.

Abstract: The present invention provides a process for production of expansion-molded articles in a mold of a linear low density polyethylene resin which comprises compressing pre-expanded linear low density polyethylene resin beads having two melting points when measured by differential scanning calorimetry and, when the melting point at a low temperature side and the melting point at a high temperature side are designated T.sub.ML and T.sub.MH respectively, between said two melting points and the peak fusion area at said T.sub.ML is designated A.sub.L and the peak fusion area at said T.sub.MH is designated A.sub.H satisfying:5%.ltoreq.A.sub.H /A.sub.L .ltoreq.

Abstract: A method for producing articles of polyurethane or the like wherein a mold of the article shape is positioned to centrifugally receive a polyurethane composition comprising polyisocyanates, polyol, water and fluorocarbons such that the polyurethane molecules striking the wall of the mold are broken to provide a resulting smooth non-porous outer skin for the article and wherein additional polyurethane materials provide a foamed interior for the article. The water serves as a reactive polyol and reacts with the polyisocyanate to create carbon dioxide gas which yields increased expansion pressure which causes the foaming polymer to produce a uniform skin around a cellular inner core.

Abstract: Precursor microporous material comprising a matrix consisting essentially of linear ultrahigh molecular weight polyolefin, a large proportion of finely divided water-insoluble siliceous filler, and interconnecting pores is stretched to increase the porosity and provide regions of stretch-induced molecularly oriented polymer in the matrix.

Abstract: A method of producing a porous material having open pores comprises the steps of preparing an emulsion slurry by vigorously agitating a mixture comprising (i) a glycidyl type epoxy resin, (ii) a first hardener selected from the group consisting of modified polyamine hardeners each being prepared by modifying a polyamine hardener with a modifier, amine hardeners and mixtures thereof, (iii) a second hardener selected from the group consisting of polyamide hardeners, (iv) a filler and (v) water, casting said slurry in a water-impermeable mold, and hardening said slurry while it contains water. A large size molded product having a complicated contour and having open pores whose average pore diameter ranges from 0.2 to 10 microns can be produced with high dimensional accuracy.

Abstract: In a process for pre-expanding thermoplastic resin particles which comprises releasing into a low pressure zone a mixture of water and thermoplastic resin particles containing a volatile blowing agent, the mixture being maintained at an elevated temperature under pressure in a pressure vessel, the improvement which comprises releasing the mixture through a plurality of orifice plates in series in the direction of release of the mixture. According to the process of the present invention, the average cell diameter of the obtained pre-expanded particles is larger than that of the pre-expanded particles obtained by means of conventional methods.

Abstract: A method of forming a foamed plastic article, comprising the steps of: injecting pressurized gaseous bubbles into a stream of heated liquid plastic; feeding the heated liquid, with entrained gas bubbles, into a mold cavity without expanding the bubbles; slowly expanding the mold cavity to permit the gas bubbles to expand and thereby produce a foamed plastic article; controlling the temperature of the mold cavity surfaces so that the plastic material is in a viscous liquid state during at least the major part of the bubble expansion process; and cooling the mold cavity surfaces to a temperature less than the melt point of the plastic.

Abstract: An improved process for producing a molded microcellular elastomer with a reduced number of voids from at least two liquid reactants and a gas, which process comprises introducing into at least one reactant a gas to form an admixture; passing the admixture through a static mixer at superatmospheric pressure; then immediately mixing the admixture with the other reactant at superatmospheric pressure to form a reaction mixture; introducing the reaction mixture into a mold in which the pressure is substantially below the superatmospheric pressures used above; and curing the reaction mixture in the mold to produce a molded microcellular elastomer with a reduced number of large voids.

Abstract: A process for producing a microcellular cast resin product, by casting a water-in-oil emulsion of polymerizable components which will gel and partially polymerize by an exothermic reaction, and placing the partially polymerized casting in a fluid medium maintained at a temperature and pressure such that evaporation of water and monomers is inhibited but sufficient to promote complete polymerization while retaining dispersed water within a microcellular structure. The water content of the emulsion can range from about 1% to about 90% by weight, and the microcellular structure may be either the open cell or the closed cell type.

Abstract: A foamed and expanded low density polyethylene sheet or tube possesses both superior buoyancy and thermal resistance characteristics. The sheet or tube is made by a process comprising mixing a low density polyethylene with a blowing agent, surface activation agent and, preferably, a separation agent, heating the mixture at different temperatures to first melt the mixture and then gasify the blowing agent to expand the polyethylene cells, cooling the melted mass to partially harden and shrink the expanded cells, further expanding the cells by introducing a second gaseous blowing agent, cutting, extruding and cooling the expanded mass, forming a sheet or tube from the cooling mass, and finally cooling the sheet or tube for at least 24 hours. A buoyant, thermal resistant, water-repellent and moisture resistant sheet or tube results, which can be used, for example, as a liner for garments, including sports, business and military garments and other related equipment.

Abstract: A method of forming foamed fibers which comprises the steps of forming a melt of a polymer of fiber-forming molecular weight in which is admixed a blowing agent, and a closed-cell-forming additive, extruding said melt through a spinnerette, quenching said melt downstream of said spinnerette under conditions at which bubbles form in said melt, and drawing said melt as it is quenched to produce a foamed fiber having fine bubbles contained therein is disclosed. The product fibers may contain substantially only closed-cells and/or substantially uniform cross sectional area cells.

Abstract: A foamed and expanded low density polyethylene sheet or tube possesses both superior buoyancy and thermal resistance characteristics. The sheet or tube is made by a process comprising mixing a low density polyethylene with a blowing agent, surface activation agent and, preferably, a separation agent, heating the mixture at different temperatures to first melt the mixture and then gasify the blowing agent to expand the polyethylene cells, cooling the melted mass to partially harden and shrink the expanded cells, further expanding the cells by introducing a second gaseous blowing agent, cutting, extruding and cooling the expanded mass, forming a sheet or tube from the cooling mass, and finally cooling the sheet or tube for at least 24 hours. A buoyant, thermal resistant, water-repellent and moisture resistant sheet or tube results, which can be used, for example, as a liner for garments, including sports, business and military garments and other related equipment.

Abstract: In a method of extruding a plastic product having a foamed core layer and at least one unfoamed skin layer by forcing contiguous flows of a resin through a coextrusion die, one of the flows containing a blowing agent and a nucleating agent for forming the core layer and the second of the flows containing only the blowing agent, for forming the skin layer, the steps of establishing a fluent stream of resin containing the blowing agent, dividing the stream into separate streams which are separately conducted to the coextrusion die to constitute the core-forming and skin-forming flows, respectively, and selectively adding the nucleating agent only to that one of the separate streams which constitutes the core-forming flow. The nucleating agent used can be one which is effectively completely expended when the core layer foams, so that the foamed product is essentially free of active nucleating agent.

Abstract: A process for making molded high resilience polyurethane cellular products which require reduced crushing in preventing the products from substantially shrinking or changing dimensionally upon cooling which comprises: exposing the curing product to atmospheric pressure while in contact with the confines of the mold at a time when the cell walls of the curing polyurethane cellular product have cured sufficiently to develop sufficient strength to partially resist bursting by the pressure of said expansion gases contained within the cell walls upon exposure to atmospheric pressure, but before the cell walls have cured sufficiently to develop sufficient strength so that exposure to atmospheric pressure does not result in a reduction of the crushing force necessary to prevent the products from substantially shrinking or changing dimensionally.

Abstract: In a method of manufacturing silica-free, interconnected porous ceramics, use is made of ceramic material powder which exhibits an expansion phenomenon due to reaction when fired; the ceramic material powder is mixed with binder; the mixture is molded; thereafter the molded mixture is fired and, during the firing process, held for a predetermined period of time at a predetermined temperature which is not lower than a temperature at which maximum expansion occurs in the expansion phenomenon but lower than a temperature at which the firing of the molded mixture is completed; and the firing process is stopped after a lapse of the predetermined period of time.

Abstract: A process for producing porous films which comprises blending 100 parts by weight of a polyolefin resin with 50 to 500 parts by weight of barium sulfate preferably having an average particle diameter of 0.1 to 7 .mu.m, melting the resulting resin composition and forming it into a film, and then stretching the film at least uniaxially by a factor of 1.5 to 7.

Abstract: A process for producing porous films which comprises melting a resin composition consisting essentially of (1) 100 parts by weight of a high-pressure-processed low-density polyethylene resin having a melt index of 0.5 to 7 and a density of 0.915 to 0.935, a linear low-density polyethylene resin having a melt index of 0.5 to 8.5 and a density of 0.915 to 0.935, or a mixture thereof and (2) 50 to 500 parts by weight of barium sulfate having an average particle diameter of 0.1 to 7 .mu.m; forming the molten resin composition into a film; and then stretching the film at least uniaxially by a factor of 1.5 to 7. As the linear low-density polyethylene resin, a copolymer of ethylene and hexene and/or octene is particularly preferred.

Abstract: A process is disclosed for the production of expanded particles of polymeric material wherein unexpanded particles of the material are contacted with a nitrogen-containing inorganic gas under a first pressure condition to impregnate the particles with the gas. The gas impregnated particles are heated to a temperature higher than the softening point of the material, and dispersed into a liquid medium. The resulting dispersion is subjected to a lower pressure to expand the particles. The expanded particles may be used as prefoamed particles for the molding of foamed articles.

Abstract: A process for producing an air-permeable film is described, comprising stretching in at least one direction a film made of a composition comprising 42 to 87 vol % of a polyolefin resin and 58 to 13 vol % of an inorganic filler and further containing an aliphatic alcohol/fatty acid ester of a fatty acid having 10 to 22 carbon atoms and an aliphatic alcohol having 1 to 12 carbon atoms in an amount of 3 to 25 parts by weight per 100 parts by weight of the above composition.

Abstract: Microporous polymeric films having good water vapor transmission rates and hydrostatic resistance to the penetration of liquid water are obtained by stretching a composition consisting of a matrix of a thermoplastic orientable polymer having a hydrophobic surface, a glass transition temperature of less than 25.degree. C., a Vicat softening point of more than about 25.degree. C., an ultimate elongation between those two temperatures of at least 100%, and a flexural modulus of less than 200 MPa and a particulate filler having an aspect ratio of less than 3, an average diameter of 0.05-50 m, a negligible attraction to the matrix polymer, and a surface tension no higher than that of the matrix polymer at the latter's melting temperature.Such films are useful in applications involving separation of liquids and vapors, e.g., in making "breathing" waterproof garments or linings.

Abstract: In a process for producing a polyethylene extruded foam, which comprises melting and kneading a composition of a polyethylene-based resin containing a foaming agent and extrusion-foaming it, a linear low-density polyethylene having a broadness of molecular weight distribution is used as the polyethylene-based resin. The linear low-density polyethylene used has a density of 0.920 to 0.940 g/cm.sup.3, a melt flow rate of 0.3 to 10 g/10 min's and a relationship Mw/Mw.gtoreq.4 between a weight average molecular weight and a number average molecular weight.

Abstract: In the case of a process for producing pourable spherical-segment-shaped packing material particles (18) made of plastic which have an external convex and an internal concave surface, the plastic material is mixed with additives, such as bubble forming agents, coloring pigments and similar agents. The plastic material is fed, by means of a feeding funnel (17) into an extruder (14) through an opening in a bush (13) surrounding the extrusion screw. The plastic material plasticizes over the course of the extruder (14) and, because of the difference in speed existing over the cross section of the mass, comes out of an opening (15) in the die with a bent surface. The plastic material is cut off directly at the opening (15) of the die and before any considerable expansion has taken place. Before the processing of the plastic granules in the extruder (14) a bubble-forming agent (nucleation agent) is applied to their surface in a drum (5).

Abstract: A reticulated hydrophilic foam substrate and bonded active surface particle powder composite filter material is generated by foam polymerization of a prepolymer phase with an aqueous phase. The reticulated hydrophilic foam substrate is characterized by relatively low pressure drop and low resistance to flow through the foam substrate. The prepolymer phase is a hydrophilic polyurethane prepolymer receptive to the aqueous phase for foam polymerization upon mixing with the aqueous phase. The aqueous phase in turn is a pourable and flowable slurry mixture of water, active surface particle powder, and surfactant wetting agent. The aqueous phase includes sufficient water or other evaporable liquid to provide a protective liquid layer or coating over the active surfaces of the powder particles.

Abstract: The foam of the present invention, which has a multi-cellular structure including many wrinkles having one end in the boundary portion where at least three cells are adjacent to one another and extending toward the central portion of the cell wall, is a rigid thermoplastic resin foam having an ultra-low density, a high sound-insulating property, a high heat-insulating property and a high flexibility, and it is suitable for adaption for building construction. The process of the present invention is to provide the aforesaid foam of the present invention by subjecting the foam of a rigid thermoplastic resin to expansion, contraction and aging.

Abstract: A process for making molded flexible polyurethane cellular products which do not substantially shrink or change dimensionally upon cooling is provided by exposing the curing product to atmospheric pressure while in the confines of the mold. Exposure can be accomplished by unlatching the mold or opening a port at an appropriate time after the reaction mixture was introduced into the mold so as to burst the cell walls of the polyurethane product.