Abstract: A method of forming an article via injection of plastics material into a mould consisting in the steps of: providing a mould tool (11) defining in its closed state a mould cavity, the mould tool being adapted to be partially expandable from an injection volume (FIG. 2) for receiving a load of plastics material to a final, larger volume (FIG.

Abstract: A method for creating a hot melt foamed form for an air induction system. A block of thermal mastic elastomer is melted and blended with nitrogen gas to create a foamed material. The foamed material is applied by robotic techniques over a base material on the surface of a polypropylene glass lower shell. After the foamed material cures, a polypropylene glass cover is applied over the foamed material form to create an air tight dust/water seal. The cover does not adhere to the cured foamed material and is removable when service is necessary. The foam material can also be dispensed into a mold and then transferred to the base, allowing for changes in the shape and profile of the foamed material. This method can also be employed to create an isolation pad on an air induction system to absorb engine shock. The thermal mastic elastomer can also be employed to create a seal between the cover neck of an air induction assembly and a mass air flow sensor.

Abstract: The invention provides systems, methods, and articles useful in the production of foams, and, in particular microcellular foams. The systems include a restriction element that reduces the backflow of polymer melt in an extruder while polymeric material is injected into a mold or ejected from a die. The restriction element is positioned upstream of a blowing agent injection port to maintain the solution of polymer and blowing agent in the extruder above a minimum pressure throughout an injection or ejection cycle, and preferably above the critical pressure required for the maintenance of a single-phase solution of polymer and blowing agent. The systems can be used in injection molding, blow molding, or in any other processing techniques that include injection or ejection cycles. In some embodiments, the systems utilize reciprocating screws for injection or ejection.

Abstract: Low-density, high service temperature polymer foam is extruded by heating a crystalline polymer resin above its crystalline melt point to melt the resin, selecting a blowing agent combination, combining the blowing agent combination with the resin to create a mixture, cooling the mixture to a temperature approaching a freezing temperature for the mixture, and extruding the foam through a die. The blowing agent combination is made up of 50 to less than 100 mole percent of a first blowing agent having a boiling temperature at STP of greater than 310° K, and more than 0 to 50 mole percent of a second blowing agent having a boiling temperature at STP of less than 310° K. The blowing agent combination has an equilibrium solubility vapor pressure in the polymer of less than 45 atm at the foaming temperature and greater than or equal to 1 atm at the glass transition temperature.

Abstract: The present invention relates to a method for producing a foamed article by which a foamed article having a high expansion ratio, having uniform fine cells in a high closed cell ratio and capable of being recycled, which is utilizable as heat insulating materials for construction, cushioning materials for wrapping, cushioning floats for ships, floats for sports and leisure and the like, can be obtained readily and safely using a clean inorganic gas as a foaming agent, and to a foamed article obtained by the method. That is, the present invention provides a method for producing a foamed resin article comprising a melting step of feeding a thermoplastic resin into an extruder and heating it to melt, a kneading step of mixing an inorganic gas with the thermoplastic resin in the extruder to produce a kneaded material, and a foaming step of discharging the kneaded material from a mold having a tubular channel mounted to the end of the extruder to form the foamed article.

Abstract: This invention provides a method for stably adding a predetermined amount of supercritical carbon dioxide at a fixed delivery rate into a forming machine and also a process for producing an expanded thermoplastic resin product by making use of the addition method. Carbon dioxide is charged from a liquefied carbon dioxide cylinder (1) into a predetermined amount deliverable pump (2) while allowing the carbon dioxide to remain in a liquefied state. When the carbon dioxide is pressurized and delivered by the predetermined amount deliverable pump (2), a delivery pressure of the carbon dioxide is controlled at an optional pressure within a range of from a critical pressure (7.4 MPa) of carbon dioxide to 40 MPa to deliver the carbon dioxide without any fluctuation of the amount of the delivery by setting up the pressure of a pressure control valve (3). The carbon dioxide is heated to a critical temperature (31° C.) of carbon dioxide or higher to convert it into supercritical carbon dioxide.

Abstract: A process and apparatus for producing polyurethane foam, comprising bringing together under pressure one or more foam components and a gaseous CO2 auxiliary blowing agent and discharging the combination through a permeable discharge head in the form of plural individual wire meshes sintered together to form at least one composite element having a structure such as to require repeated division, divergence and convergence of flow paths and impingement of the individual flows with the sintered wire mesh and the flows through adjacent pores in three dimensions within its axial thickness, and at which the pressure is reduced for forming a froth, wherein the combination of the foam components and gaseous CO2 is arranged to be in a non-homogeneous state containing gas bubbles prior to passage through the discharge head.

Abstract: The invention includes a process comprising (a) forming a polymeric admixture including at least one polyolefin which has been prepared using a single site catalyst and at least a crosslinking amount of at least one poly(sulfonyl azide) crosslinking agent; (b) shaping the resulting admixture; and (c) heating the resulting shaped admixture to a temperature at least the decomposition temperature of the crosslinking agent. The steps take place in any sequence and optionally include substeps. The single site catalyst is preferably a constrained geometry or metallocene catalyst, but optionally another transition metal catalyst which is not a traditional Ziegler Natta Ti/MgCl2 catalyst such as a vanadium catalyst. The invention further includes all compositions obtainable by the process of the invention as well as all articles formed from these compositions.

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: The invention provides a blowing agent delivery system for introducing a blowing agent into a polymeric foam processing system. The delivery system is designed to discontinuously introduce blowing agent from a continuous source into polymeric material within an extruder. The system, thus, may improve control over blowing agent delivery in discontinuous polymer processing systems such as injection molding or blow molding. In some embodiments, the blowing agent delivery system selectively directs blowing agent flow from the source to the extruder barrel, or through a bypassing passageway. In this manner, blowing agent may be continuously supplied by the source but discontinuously injected into the extruder barrel. During use, the delivery system may cause blowing agent to flow through the bypassing passageway, for example, when the screw stops plasticating polymeric material.

Abstract: The invention relates to a novel process for the manufacture of functionalized polyphenylene ether resins through redistribution with a functionalized phenolic compound in the polyphenylene ether resin polymerization reaction solution without the addition of an added redistribution catalyst or promoter. The invention also relates to the functionalized polyphenylene ether resin made by the process as well as blends and articles containing the functionalized polyphenylene ether resin made by the process.

Abstract: The invention relates to a novel process for the manufacture of very low molecular weight polyphenylene ether resin, typically within the intrinsic viscosity range of about 0.08 dl/g to about 0.16 dl/g as measured in chloroform at 25° C. The method preferably comprises 2,6-dimethylphenol as a monovalent phenol species. The invention also relates to the polyphenylene ether resin made by the process as well as blends and articles containing the polyphenylene ether resin made by the process.

Abstract: The invention relates to a novel process for the manufacture of very low molecular weight polyphenylene ether resin, typically within the intrinsic viscosity range of about 0.08 dl/g to about 0.16 dl/g as measured in chloroform at 25° C. The method preferably comprises 2,6-dimethylphenol as a monovalent phenol species. The invention also relates to the polyphenylene ether resin made by the process as well as blends and articles containing the polyphenylene ether resin made by the process.

Abstract: A method and apparatus for making a chemical mechanical polishing (CMP) article dissolves gas into solidifiable material, and reduces pressure on the solidifiable material to form gas bubbles therein while solidifying the solidifiable material to make a matrix with voids therein. The gas bubbles are preferably formed to define voids interconnected with adjacent voids to thereby define a porous matrix. The porous matrix ensures uniform distribution of the CMP slurry for greater polishing uniformity. The method produces a CMP pad, for example, with very uniform porosity throughout its thickness so that polishing remains uniform as the pad is consumed in use. The gas and the solidifiable material may preferably be non-reactive with one another. The gas may comprise at least one inert gas, such as nitrogen or argon, for example. The solidifiable material may be a polymer-forming liquid and at least one of a curing and cross-linking agent mixed therein.

Abstract: The cylinder head (8) of an injection molding machine has a transverse bore (20), in which is threadedly engaged a gas introduction device (21) connected to a gas bottle (22), having a pressure regulator (23). The device has a body (24) which carries a valve poppet (25) in a complementarily shaped bore (26) opening to the passage through the cylinder head. A spring (27) normally closes the poppet valve. A control valve (28), under control of the system (7) is provided upstream of the poppet valve. Gas is introduced into the injection chamber of the machine after suck back and before screw rotate for feeding plastics material to the injection chamber. On injection, the material is injected with the gas added to it.

Abstract: A method for manufacturing a plastic object may include the steps of: (a) providing an injection moulding device with a mould that includes two mould parts which in a closed position define a mould cavity; (b) providing foaming means for causing foaming in the mould cavity of plastic injected into the mould cavity; (c) providing blocking means for temporarily rendering the foaming means effectively inactive; (d) energizing the blocking means; (e) choosing as plastic a mixture of two plastics, wherein the first plastic is a non-type A plastic and the second plastic is a type A plastic that constitutes a maximum of roughly 30 percent by mass of the mixture, wherein the type A plastic is a plastic with high melt strength compatible with the first plastic, for instance HMS PP which is high-melt-strength polypropylene; (f) causing a formed object to cool to a chosen temperature, opening the mould cavity and removing the cooled object.

Abstract: The present invention is polyurethane dispersion composition that can be mechanically frothed to yield a foam that has good resiliency. Frothed foams of the present invention can be useful in cushioned flooring applications such as attached cushion broadloom, carpet tiles, carpet underlay, or vinyl flooring. Frothed foams of the present invention can also be useful as coatings for various textiles and for diapers.

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 making a polymer foam sheet, which comprises (i) extruding through an annular extrusion die a foamable composition comprising at least one polypropylene polymer and at least one blowing agent, at a pressure, temperature, and extrusion rate sufficient to prevent foaming of the composition prior to exiting the die, under conditions sufficient to form a foam tube having a density of at least 16 kg/m3 and no greater than 200 kg/m3, an open cell content of less than 70 percent, a circumference of at least 1 meter, and a foam thickness of at least 2 mm and no greater than 25 mm, wherein the blowing agent is used in an amount of from 0.2 to 4.

Abstract: A flexible, low density thermoplastic foam and a method for lowering the density and increasing the flexibility of a thermoplastic foam having a melting temperature and being either amorphous with a softening temperature or semicrystalline with a glass transition temperature.

Abstract: The invention includes a process comprising (a) forming a polymeric admixture including at least one polyolefin which has been prepared using a single site catalyst and at least a crosslinking amount of at least one poly(sulfonyl azide) crosslinking agent; (b) shaping the resulting admixture; and (c) heating the resulting shaped admixture to a temperature at least the decomposition temperature of the crosslinking agent. The steps take place in any sequence and optionally include substeps. The single site catalyst is preferably a constrained geometry or metallocene catalyst, but optionally another transition metal catalyst which is not a traditional Ziegler Natta Ti/MgCl2 catalyst such as a vanadium catalyst.

Abstract: A method for continuously producing a rigid polymer foam in rolled form comprising (a) continuously conveying a carrier along a production line, (b) depositing on the carrier a foam-forming mixture, a regulating means being located on the production line to ensure deposition of only enough of the foam-forming mixture for production, after foaming and curing, of a rigid foam having a maximum thickness of less than 1 inch, (c) foaming and curing the deposited foam-forming mixture to produce a rigid foam, and (d) rolling the rigid foam.

Abstract: The invention relates to a novel process for the manufacture of very low molecular weight polyphenylene ether resin, typically within the intrinsic viscosity range of about 0.08 dl/g to about 0.16 dl/g as measured in chloroform at 25° C. The method preferably comprises 2,6-dimethylphenol as a monovalent phenol species. The invention also relates to the polyphenylene ether resin made by the process as well as blends and articles containing the polyphenylene ether resin made by the process.

Abstract: An extrusion system is provided with a screen changer between in-line screw sections. An in-line seal diverts high pressure, high temperature foamable material toward the screen changer. The seal may have reverse flights to provide a visco-dynamic seal. The screw sections and the seal may be located in a common barrel housing. The screw sections and the seal may be integrally rotated as a single in-line unit. A device including an injection valve may be attached to the upstream screw section to introduce a foaming agent into the material being extruded.

Abstract: The present invention relates to foamed products. More particularly, the present invention relates to foamed products comprising a plurality of coalesced extruded strands or profiles or layers of a foamed thermoplastic composition having a low density.

Abstract: The present invention relates to a process for the preparation of a foamed article having a foam density of less than 180 kg/m3 and an average cell diameter of less than 1.5 mm comprising the extrusion of a molten semi-crystalline thermoplastic resin composition in the presence of a foaming agent, with the semi-crystalline thermoplastic resin composition comprising a polymeric epoxide containing at least two epoxide groups being a copolymer of a monomer mixture comprising at least one C10 to C18-olefin and at least one ethylenically unsaturated compound comprising an epoxide group. The process results in the preparation of foamed articles having a regular and homogeneous structure. Another advantage of the present invention is that it is not necessary anymore to add a compound of Group Ia, IIa, or IIIa of the Periodic Table, such as LiCl, to the extrusion process.

Abstract: The present invention is directed to a pre-inked thermoplastic foam which is utilized to form a relief image which includes open cells in the area that is designed to transfer ink and enclosed or sealed cells in the area which is designed to be impermeable to ink or other print medium. The present invention also includes the method of using and manufacturing the pre-inked foam.

Abstract: A plastic foam article 1 produced by extrusion, for example, a plastic foam sheet comprising homopolymers and copolymers of polycyclic olefins, contains at least 10% by volume of open cells 2, 4 which have a polyhedron-like shape and adjoin one another. The deformation-free opening of the cells is brought about by means of an extrusion temperature higher than that for the extrusion of thermoplastic plastic foam articles having a closed-cell structure. This leaves webs 3 of cell walls 5, 6 intact in terms of shape, whether they now have openings 7 or have no through passages, so that the mechanical strength of the cell framework or the three-dimensional matrix is retained.

Abstract: The present invention is directed to a method of obtaining a gas-introduced fiber-reinforced resin injection molding and to a molding obtained by the method. According to the present invention, there can be obtained a lightweight gas-introduced fiber-reinforced resin injection molding containing glass fibers or like fibers having excellent rigidity and strength and improved surface properties.

Abstract: A spinning process using azeotropic compounds as spin agents having essentially zero ozone depletion potential and that are either non-flammable or of very low flammability.

Abstract: A method of producing an extruded plastics foam of enhanced physical strength includes intimately mixing a blowing agent incorporation CO.sub.2, the major portion of which is a natural gas, in a plastics resin melt to form a homogenous resin mix, and extruding the resin mix through an exit die into a region of lower pressure. At the point of extrusion out of the exit die, the temperature of the resin mix is adjusted so that it is below the critical temperature.

Abstract: In one embodiment, the present invention relates to a process for preparing foam board or sheet including the steps of (A) forming a foamable mixture of (1) a major amount of a styrenic polymer having a high melt index, (2) a minor amount of a low melt index styrenic polymer, and (3) a blowing agent containing a major amount of carbon dioxide under a pressure sufficient to prevent prefoaming of the mixture, and (B) foaming the mixture into a region of reduced pressure to form a foam product.

Abstract: A method for extruding foam of a thermoplastic elastomer, which is a blend of olefin rubber and polyolefin resin, includes the steps of mixing the thermoplastic with water, introducing the mix to an extruder, melting and compressing the thermoplastic elastomer and water and extruding the resultant mix as foam. In more detail, a first quantity of thermoplastic elastomer in pellet form is mixed with a second quantity of water. The mixed water and thermoplastic is introduced to an extruder. The thermoplastic elastomer is melted and mixed with the water to a uniform mix of thermoplastic elastomer and water. The mix is extruded through a die, wherein the water expands in a vapor form to create foam cells with the cells having walls of the thermoplastic elastomer.

Abstract: In one embodiment, the present invention relates to a process for preparing a foam product including the steps of (A) forming a foamable mixture of (1) an alkenyl aromatic polymer and (2) a blowing agent under a pressure sufficient to prevent prefoaming of the mixture and (B) foaming the mixture into a region of reduced pressure to form the foam product, wherein the difference between the glass transition temperature of the foamable mixture and the foaming temperature is less than about 62.degree. C.

Abstract: The invention disclosed provides a method for inducing nucleation in a polymer by subjecting the polymer containing dissolved gas to an external stress generated, for example, by applying hydrostatic or mechanical pressure. The applied stress restricts the bubble growth so that the foamed materials have small cells and high cell density. Such microcellular foams can be produced over a wide low temperature range, i.e. from the temperature at which the polymer is conditioned with the blowing agent up to about the glass transition temperature of the polymer-blowing agent system. Stress induced nucleation can also be conducted at higher temperatures i.e. up to about the T.sub.g of the neat polymer, leading to foams with larger cells. A variety of homogeneous and heterogeneous foams can be produced by this technique.

Abstract: Low-density, high service temperature polymer foam is extruded by heating a crystalline polymer resin above its crystalline melt point to melt the resin, selecting a blowing agent combination, combining the blowing agent combination with the resin to create a mixture, cooling the mixture to a temperature approaching a freezing temperature for the mixture, and extruding the foam through a die. The blowing agent combination is made up of 50 to less than 100 mole percent of a first blowing agent having a boiling temperature at STP of greater than 310.degree. K, and more than 0 to 50 mole percent of a second blowing agent having a boiling temperature at STP of less than 310.degree. K. The blowing agent combination has an equilibrium solubility vapor pressure in the polymer of less than 45 atm at the foaming temperature and greater than or equal to 1 atm at the glass transition temperature.

Abstract: An extrusion system for providing a foamed material in which a material such as a polymer material is supplied to an extruder for movement through a rotating screw member. The material is placed in a molten state and a foaming agent, such as a supercritical fluid, is introduced into the extruder at a selected pressure so that a two-phase mixture of the molten material and the foaming agent is formed. The foaming agent is then diffused into and dissolved in the molten material to form a single-phase solution which is forwarded from a solution formation to a nucleation device. A thermodynamic instability is induced through a rapid pressure drop, e.g., higher than 0.9 GPa/s in the nucleation device to nucleate microcells in the solution. A further shaping device, e.g., a die, can be used to produce a foamed material of a desired shape.

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 process for the manufacture of polyurethane foam comprising the steps of (i) mixing at a reaction index of 40 to 400: (a) a polyisocyanate blend comprising at least one polyisocyanate and optionally, additives and fillers; (b) a polyol blend comprising isocyanate reactive components and optionally, water, additional blowing agents, catalysts, surfactants, fillers and other additives; wherein either or both said polyisocyanate blend or said polyol blend contain between 0.3 to about 20 wt. % CO.sub.2 based on the total weight of said polyisocyanate blend and said polyol blend; (ii) introducing and uniformly mixing in liquid form of CO.sub.2 as a blowing agent into either or both said polyisocyanate blend or said polyol blend and maintaining said CO.sub.2 in said liquid form. The present invention also relates to an apparatus, which performs the above-mentioned process.

Abstract: The present invention provides pre-expanded noncrosslinked polyethylene resin beads which are made of a mixed resin, as a base resin, comprising a high-pressure-process low-density polyethylene, a linear low-density polyethylene, and a linear high-density polyethylene and, when analyzed with a differential scanning calorimeter (DSC), give a fusion endothermic curve which is a mountain-shaped curve having a single peak and in which, when the peak point of the mountain-shaped curve is referred to as A, the point of intersection of the perpendicular line drawn to the temperature axis from A and the base line of the fusion endothermic curve is referred to as B, and the two points at which the straight line drawn through the point C interiorly dividing segment AB in the perpendicular line in a ratio of 9:1 and parallel to the temperature axis intersects the fusion endothermic curve are referred to as D and E, then that temperature width of the mountain-shaped curve part which is the length of segment DE is 15.

Abstract: A process and device for the continuous production of slabstock foam by foaming a polyurethane reactive mixture containing carbon dioxide dissolved under pressure, comprising the steps ofa) feeding said polyurethane reactive mixture into a linear extended pressure distribution chamber at a pressure above that of the solubility vapor pressure of said dissolved carbon dioxide,b) reducing pressure to a pressure below said solubility vapor pressure of said dissolved carbon dioxide in a linear extended pressure reduction zone,c) feeding said polyurethane reactive mixture from said pressure reduction zone into a foaming chamber with a widening cross-section of flow to form a foamed reactive mixture, andd) applying said foamed reactive mixture (froth) substantially perpendicularly and free-flowing onto a conveyer belt of a continuous slabstock foam plant.

Abstract: Methods for impregnating polymer beads comprise providing polymer beads in an impregnation chamber at a temperature from about 150.degree. F. to about 200.degree. F. and a pressure of from about 25 psig to about 100 psig, and simultaneously fluidising the polymer beads in the impregnation chamber with an impregnating gas. The gas is delivered to the chamber at a rate sufficient to cause individual polymer beads to be fluidised and for a time sufficient to impregnate the gas in the polymer beads. The apparatus adapted for such methods includes a heater, a compressor and a plurality of vents for supplying a gas to the impregnating chamber to fluidise polymer beads contained therein simultaneously with the heating and pressurising of the beads.

Abstract: A latex leather sheet fabrication method includes the steps of (a) pre-heating natural latex to about 30.degree. C.; (b) flow mixing pre-heated natural latex with a chemical solution containing oleic acid, sulfur and zinc oxide powder by flow mixing for about 1.about.3 hours; (c) mixing the latex mixture with forced air into a foamed viscous liquid; (d) shape-forming the foamed viscous liquid into a hardened foamed sheet material; (e) heating and drying the foamed sheet material into a foamed leather sheet; and (f) air cooling the finished latex leather sheet.

Abstract: The invention relates to a process for producing loose fill in the form of spherical segments having a convex outer surface and a concave inner surface, and the granules formed. It is provided that starch granules are fed into a drum, and that in the drum, a nucleating agent is drum-coated onto the starch granules, and that the starch granules drum-coated with the nucleating agent are fed to an extruder, in which the starch granules are converted from their solid state into a viscous-liquid state. A starch foam created, by furnishing heat, in the extruder by the decomposition of the nucleating agent emerges from a forming opening of the extruder with a curved surface as a result of the difference in speed prevailing over the cross section of the composition, and that the skein of starch emerging from this forming opening is cut off directly at the forming opening, before any considerable expansion has taken place. The thus-created starch particles are received in a storage container.

Abstract: An apparatus and process for producing polymeric foam, wherein reactive foam components and a low-boiling point frothing agent are brought together, sufficient pressure is applied to maintain the frothing agent in a liquid state and the mixture is passed through a permeable discharge head through which the mixture is discharged and wherein the pressure is reduced and froth is formed. The discharge head comprises one or more diffuser elements (80) having a structure such as to require division, divergence and convergence of flow paths in three dimensions within the axial thickness of the diffuser element, considered in the direction of flow therethrough. The diffuser element (80) is made of bonded, or sintered or sintered composite material, such as sintered wire.

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 method of making a polyolefinic foam composition comprising the steps of:(a) feeding a polyolefinic polymer into an extruder;(b) adding a nucleating agent to the resin feed;(c) optionally adding a permeation modifier to the resin feed;(d) plasticating the mixture in an extruder to form a polymeric melt;(e) incorporating a blowing agent of carbon dioxide and optionally one or more members selected from the group consisting of inorganic blowing agents, organic blowing agents, and combinations thereof;(f) incorporating at least one compatibilizing agent into said foamable composition wherein said compatibilizing agent is an oxygenated hydrocarbon that decreases the minimum pressure required to prevent prefoaming while retarding the collapse of foam due to excessive blowing agent migration;(g) uniformly mixing and cooling the foamable composition to a temperature effective for the expansion of the polyolefinic foam; and(h) extruding or ejecting the foamable composition through a die to form a polyolefinic foam.

Abstract: A process for fabricating a foamed plastic product. The process includes a plastic film that is prefoamed in order to introduce lamellar discontinuities such as prefoamed bubbles. The film is pressurized by a gas under a positive pressure causing the gas to diffuse into the film, forming a second film. Further, the second film is inflated in order to form the foamed plastic product. The second film is inflated by heating the second film at a temperature below the melting point of the second film and under a reduced pressure.

Abstract: The invention disclosed provides a method for producing ultramicrocellular polymer foams at low pressures. A polymer is saturated with a blowing agent at low temperatures and pressures within a short time period, due to retrograde vitrification. The blowing agent may be in the form of a gas or a volatile liquid. Polymer-blowing agent combinations are selected to provide a processing temperature/pressure in the area below the positive slope portion of the retrograde vitrification profile of the glass transition temperature of the polymer versus pressure. The polymer thus saturated has an exceptionally high blowing agent content, and is then foamed to produce materials with small cells and high cell density.

Abstract: A method for continuously producing an insulation board comprising a rigid plastic foam core having two major surfaces and a facing material on one or both of the major surfaces, the method including conveying a facing material along a production line, depositing a partially expanded froth foam of a plastic mixture, which contains at least one frothing agent, on the facing material, and further expanding and curing the froth foam in contact wiht the facing material to form the insulation board. The board is particularly useful as roof insulation.