Abstract: A molding process in which a material with an open cell, porous structure 10 is placed, aligned or supported inside a suitable enclosed holding device. Another molding material 20 is subsequently injected into the said holding device while gas and/or pressure is sequentially applied to the said holding device, causing a synergistic interaction and joining between the said materials to take place. During the processing phase, gas is evenly dispersed throughout the porous core, effectively equalizing cavity pressure and permitting an even flow pattern to exist, encapsulating or sandwiching the said porous structure, thus forming a composite material with physical properties which are substantially greater than the individual components.

Abstract: A protector made of thermoplastic resin to which a foaming agent is added is adapted such that no foams are present in the thermoplastic resin forming a predetermined volume area including lock portions mounted on a protector body for integrating the protector body and a lid element but foams are present in the thermoplastic resin forming the area other than the predetermined volume area, whereby a molded part of thermoplastic resin is provided which accomplishes weight reduction and an insured strength at a strength-required area.

Abstract: A carpet pad has pressure sensitive adhesive preapplied on one or both surfaces, for retaining the pad and a carpet in place on a floor by adhesion without the need for stretching. The pad or cushion in one embodiment has a film or sealant on the surfaces of the pad, with pressure sensitive adhesive on at least one of the sealed surfaces for adhering to floor surface or the underside of a carpet. In another embodiment, the pressure sensitive adhesive is a hot melt adhesive, not water-based. The hot melt pressure sensitive adhesive is applied to an uncoated porous padding surface which would be unsuitable for a water-based pressure sensitive adhesive due to excessive wicking-in of such an adhesive. An optional scrim webbing may be applied over the pressure sensitive adhesive, in either embodiment. The scrim webbing adds dimensional stability and also enables the carpet pad to be moved around on a floor or against another surface without sticking, prior to the application of pressure.

Abstract: In a method of preparing a urethane foam article having a high density outer surface layer, of the type wherein a plastic liquid containing isocyanates, polyols, a catalyst, a blowing agent, an assistant and other additives is poured into a mold through a one-shot molding process, while maintaining the mold at a temperature in the range of from 15.degree. to 40.degree. C., a temperature sensitive catalyst is added for causing the isocyanates and the blowing agent to create a difference in chemical reaction between an outer portion of the plastic liquid contacting the mold surface and an inner portion of the plastic liquid held out of contact with the mold surface, thereby retarding the foaming of the outer portion than that of the outer portion.

Abstract: Solutions of segmented polyurethanes are coagulated to form flat circular microporous structures having a substantially continuous pore-free surface and a substantially open pore surface.

Abstract: A process for preparing polyurethane integral skin foam with low ozone depletion potential, which comprises mixing 100 pph of a polyether polyol, 5-50 pph of a chain extender, 0.1-2.0 pph of a surfactant, 0.01-0.20 pph of an amine and 0.01-0.20 pph of an organotin catalyst, 0-3.0 pph of a nucleating agent and 1.0-30 pph of a blowing agent comprising 50 to 100 weight percent of HCFC-123 and 50 to 0 weight percent of HCFC-141b to form a polyol mixture; blending said polyol mixture with isocyanate having an ISO index=0.95 to 1.10 and reacting said blend at a temperature from 0.degree.-70.degree. C. in a mold at a temperature of from 10.degree. to 90.degree. C. for a molding time of 1 to 9 minutes to form a polyurethane integral skin foam, and the product of said process.

Abstract: Asymmetric polyacetylene polymer membranes having both improved selectivity and improved flux are provided by a process which comprises forming a solution containing from about 1 to about 5% by weight of a polyacetylene polymer in any suitable solvent therefor, forming the solution into a thin film and quenching the film in an aqueous bath in the presence of from about 0.002 to about 0.4% by weight of the quench bath of surfactant with an HLB value of 11 to 15. Additionally, the polyacetylene polymer solution contains a swelling agent at about 1% to about 10% by weight of polyacetylene polymer solution.

Abstract: A method is provided for producing an integral skin foam article made up of a skin, foam and core member. According to the method, an expanded layer which is of the same material as the skin is formed on the back of the skin prior to forming the article.

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: This invention concerns cosmetic applicators for low-viscosity liquid cosmetics. In particular, it relates to an applicator surface consisting of a latex foam having a combined structure including closed cells and open cells. The structure has a porosity for the open cell portion increasing from the area adjacent the closed cells toward the other side of the latex foam applicator. The latex foam can be natural or acrylonitrile-butadiene latex foam.

Abstract: A plastic pipe with a hard outer shell lined with an inner shell of soft resilient plastic foam with a smooth central axial passageway adapted to be a conduit for liquid. A method of manufacturing this pipe which comprises simultaneously extruding the material for the outer shell and the foamable material for the inner shell into a pipe forming die.

Abstract: A method of making a foam injection molded article is disclosed wherein corrosion of the mold element is significantly reduced or substantially eliminated. The method comprises dispersing effective amounts of a primary chemical blowing agent of sodium borohydride and an activation system of sodium bicarbonate/citric acid mix into a polymer resin to form a mixture. The mixture is then heated whereby the activation system releases water and the sodium borohydride reacts with the water to produce hydrogen gas. The mixture is subsequently injected into a mold to obtain expansion of the polymer resin to form the foam article. The invention also comprehends a corresponding chemical blowing agent composition.

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: Molded polyurea foam parts having densities of from 200 to 600 kg/m.sup.3 and a compact skin are made by reacting a polyisocyanate component with a polyamine component in a closed mold at an isocyanate index of from 70 to 130. The polyamine component generally includes (1) an aminopolyether having a molecular weight of from 1800 to 12,000 and 2 to 3 isocyanate reactive groups of which at least 90% are aromatically bound primary and/or secondary amino groups, (2) an aromatic diamine, (3) a foaming agent and optionally (4) known auxiliaries and additives. The polyisocyanate component includes any aromatic di- and/or poly-isocyanate. Parts produced by this process have excellent mechanical properties and a well-defined solid skin.

Abstract: A gas separation membrane has a dense separating layer about 10,000 Angstroms or less thick and a porous support layer 10 to 400 microns thick that is an integral unit with gradually and continuously decreasing pore size from the base of the support layer to the surface of the thin separating layer and is made from a casting solution comprising ethyl cellulose and ethyl cellulose-based blends, typically greater than 47.5 ethoxyl content ethyl cellulose blended with compatible second polymers, such as nitrocellulose. The polymer content of the casting solution is from about 10% to about 35% by weight of the total solution with up to about 50% of this polymer weight a compatible second polymer to the ethyl cellulose in a volatile solvent such as isopropanol, methylacetate, methanol, ethanol, and acetone. Typical nonsolvents for the casting solutions include water and formamide.

Abstract: A method of re-shaping polyimide and modified polyimide foam sheets into selected shapes. Polyimide foam sheets can be made by any of a number of methods, some of which produce sheets of selected thicknesses directly and others of which produce blocks or buns of foam which are sliced into sheets. A sheet is placed in a mold having the desired configuration, such as a half-pipe. The sheet is compressed to about 0 to 99% of the original thickness with heating of one or both major surfaces of the sheet to a temperature of from about 250.degree. to 320.degree. C. for about 0.5 to 5 minutes. Upon removal from the mold, the polyimide foam is found to be self-supporting and to have taken on the mold shape. A moisture impervious densified skin is found on the heated side(s).

Abstract: A mold for use in heat expanding prefoamed polystyrene beads to form a part of a predetermined shape is disclosed. The mold comprises a cavity defined by separable mold wall portions. Each mold wall portion has on its exterior a chamber into which a heating medium is introduced to heat the mold walls and also into which cooling medium is introduced to cool the walls. A plurality of nozzles are provided in the mold walls and a corresponding plurality of tubes interconnect the nozzles to a manifold located in the corresponding chamber. A pressurized heating medium is introduced to the manifold whereby the heating medium is injected into the cavity to expand prefoamed polystyrene beads in the cavity. A device is provided on the manifold for the selective removal of condensate from the manifold. The mold construction provides for an economical, readily manufactured unit.

Abstract: A method of producing thermoplastic resin foams is disclosed. The method comprising extruding an expandable resin through a plurality of holes bored in a die in the inside of a frame fitted to the extrusion end surface of the die in an adjacent relation therewith and fusing together the thus-extruded materials while they are expanded and still softened, wherein the inner surfaces of the frame are inclined at an angle of inclination ranging between 5.degree. and 30.degree., so that the cross-sectional area of the frame is increased toward the outer end thereof, and the extruded materials are fused together while kept in contact with the inner surfaces of the frame.

Abstract: Ventilated thermoplastic polymer foam filter rods and the processes for their preparation. The ventilated thermoplastic polymer foam filter rods are characterized by the presence of at least some cells which are bridged by fibrils, the rod being surrounded by a high density skin structure having a discontinuity such as to produce a ventilation of at least 50%. Discontinuity in the skin structure may be produced by skin solvent etching, skin abraiding, skin perforating and skin cutting.

Abstract: The invention relates to a process for the continuous manufacture of foamed sheets of thermoplastic material having an extreme width to thickness ratio, small thickness tolerance, a uniform cell structure and, over the whole cross section on both sides of the sheet a thin, non-foamed outer skin. The plastic, which already contains the foaming agent is, on emerging from a wide-slit nozzle, allowed to foam freely without any restriction and cool. The sheet or strip formed in this manner is then heated locally at the surface and calibrated to final dimension.

Abstract: This apparatus is used to improve the heat distribution on the cavity surface in foam molding dies where a smooth finish on the resin filled foam molded plastic product manufactured by an injection molding process is desired. This invention improves the method for heating the mold cavity using a condensing vapor in a molding die by a channel and slit type orifice means in the mold around a portion of the periphery of the part to be molded. Another channel and slit type orifice means around the remaining periphery is included in the die for removing the condensing vapor or condensate from the mold cavity. During the heating process when condensing vapor is introduced into the mold the sprue opening to the extruder is sealed by a valve means to prevent condensate from collecting therein.

Abstract: A method for making closures resembling natural cork for sealing liquid product containers is described. A strand of expandable plastic material is injected into each mold cavity and is permitted to collect in that cavity in randomly oriented groups of coils which expand to fill the cavity and coalesce to create randomly oriented grain lines on the surface of the closure resembling the appearance of natural cork. Also described are methods of molding the closures which preclude the formation of leakage channels on the closure surface and preferred blends of plastic resins and pigment particles used to achieve the cork-like appearance.

Abstract: An improved article made of foamed glass or similar materials and method of manufacture is disclosed. Thus, a construction panel may be formed to bear weight, withstand weather and take reasonable impact and abuse, because of a tempered outer skin supported inside by a skeletal network of solid poreless material formed about low density pockets of substantially constant size and frequency.These panels are made by continuous pulling of the panels through a heat controlled mold in contact with the surface skin from a continuously fed molten mass into which is injected from the bottom size and frequency controlled foaming agents or gaseous bubbles which rise in the molten mass to a position where they are frozen in place.

Abstract: The instant invention relates to a process for the production of polyurethane foams by reacting polyisocyanates with polyhydroxyl compounds of a specified molecular weight range in the presence of blowing agents and chain lengthening or cross-linking agents and optionally in the presence of catalysts, foam stabilizers and other additives generally known. The improvement resides in(a) the polyisocyanates used containing aliphatically and/or cycloaliphatically bound isocyanate groups;(b) the polyhydroxyl compounds used containing ether groups; and(c) the chain lengthening or cross-linking agents comprising at least in part a member selected from the group consisting of a monoalkoxylated hydrazine, a dialkoxylated hydrazine, a reaction product of a monoalkoxylated or dialkoxylated hydrazine with an aliphatic monoisocyanate in a molar ratio of 1:1. The reaction is carried out in the presence of additional chain lengthening agents having a specified molecular weight.

Abstract: This invention relates to an improved single-stage process for the production of elastic shaped articles having an impervious surface layer by the reaction injection molding technique in which highly reactive systems of polyisocyanates, relatively high molecular weight polyhydroxyl compounds and aromatic polyamines are used.

Abstract: A method of molding articles of plastic having an expanded plastic cellular core using a closable and sealable mold having a sealed mold cavity and including at least one mold core extending into the cavity, comprises, directing the plastic melt material containing a foaming agent into the mold cavity under pressure so as to form a flow front of the melt which progresses through the cavity and which spreads out in all directions and flows around the mold core and tends to form a pocket of gas in the vicinity of the mold core, and venting the cavity adjacent the core so as to remove gas from any gas pocket which may be formed in the vicinity of the core. The apparatus for carrying out the invention includes a vent line which extends from the cavity in the vicinity of the mold core out of the cavity and which has a control valve for opening the vent line to vent any gas which forms in the cavity and which might tend to form a pocket after the buildup of a pressure in the mold cavity.

Abstract: This invention substantially improves the surface finish on resin filled foamed molded plastic products manufactured by injection molding by pre-heating the skin surface of that part of the mold in contact with the part prior to the injection cycle of the machine and then subsequently chilling the mold via internal tube connections to shorten the time needed in the manufacturing cycle for solidifying the part sufficiently for release from the mold.

Abstract: The instant invention is directed to a process for the continuous production of block-shaped foam and to the equipment used therefore. The process of the invention broadly involves the heating of the bottom film prior to application of the foamable mixture. In this way, the undesirable crust generally formed on the bottom of the foam blocks is substantially reduced and/or eliminated.

Abstract: A process for producing an expanded article of a thermoplastic resin by extruding and expanding a foamable resin using an extruder equipped, on a resin channel in a die, with a nozzle having a number of apertures, which comprises flowing a resin mixture stream through an expansion zone while maintaining the resin mixture at a temperature above the melting point thereof, dividing the resin mixture stream into a plurality of separate streams, exiting these streams from the extrusion zone directly into a confined zone, thereby forming a plurality of soft expanded resin strands corresponding in number to the number of strands, bringing the strands into surface contact with each other to fuse and bond them together to form a bonded expanded resin mass while simultaneously removing gases generated in the course of extrusion and expansion, passing the bonded mass into an unconfined zone to permit the mass to further expand while still in a softened condition, passing the further expanded mass into a confined receivi

Abstract: A synthetic foam roofing system having roofing sections with a relatively broad undersurface and exposed surface configured to resemble interlocked and overlapping roofing shingles. Ridge, valley, hip, starter gable and starter course shingles are all constructed in a manner similar to the roofing sections to interface and interlock with the roofing sections. The roofing sections and interfacing components may be affixed by conventional means such as nails and adhesives to roof boards, rafters or over old existing roofing structures utilizing wood batting.

Abstract: An impact energy-absorbing, low density urethane foam for use in automobile bumpers has good moldability and is relatively temperature insensitive, i.e. gives approximately the same physical performance over a wide range of temperatures. This foam is characterized by its good multiple impact performance and low compression set values. The foam is water blown in a closed mold from a quasi-prepolymer system. The molded density is preferably in the range of 5 to 10 PCF.The foam formulation is based on a polymer polyol of a poly (oxypropylene/ethylene) triol reacted with a styrene/acrylonitrile monomer mixture which triol thus modified is reacted with (1) a roughly 1/5 to 1.5/1 weight amount of a hydroxy terminated polybutadiene homopolymer based on polymer polyol, (2) a 50 to 150 equivalent weight polyol crosslinker of 2 to 6 functionality, (3) a MDI glycol or triol quasi-prepolymer, and (4) some water.

Abstract: A bung for closing a wine bottle in the manner of a cork is formed in a conventional injection-moulding machine from ethylene-vinyl acetate copolymer (EVA) with the addition of sodium metabisulphite and sodium bicarbonate. The sodium metabisulphite, which is in stoichiometric excess in relation to the sodium bicarbonate, decomposes to liberate sulphur dioxide. The sodium bicarbonate decomposes to liberate water and carbon dioxide. The bung as moulded accordingly has a foamed core with a liquid-impervious skin. It contains sulphur dioxide, and water enabling the sulphur dioxide to act as an oxygen scavenger when the bung is in use in a wine bottle. The bung therefore provides the bottle with a long shelf life, with no noticeable tainting of the wine.

Abstract: A molding composition is disclosed for forming in a single step a natural sandwich foam product having a cellular core and a thick, densified outer layer. A hard, particulate filler material such as fly ash is admixed with an unreacted, rigid polyurethane foam system, together with a density distribution control agent such as carbon tetrachloride which lowers the viscosity of the admixture. In molding, the mold cavity is charged with the admixture and the foam reaction is permitted to occur with the mold closed. The resultant, filled foam product has a thick outer layer formed adjacent the mold surface of substantially greater density than its core. In the densified layer, both the polyurethane and filler material components of the resultant product are concentrated to provide over three times the density of the core structure. Formulations are set forth which provide substantial layer thickness and an outer surface having a durometer hardness value of 50 or greater over the entire surface area.

Abstract: Shaped synthetic-resin bodies are made in a separable mold by injecting a flowable mass of a synthetic-resin material into the mold cavity. To precool the mass and cause an initial setting at least of the surface thereof, a liquefied gas, i.e. a low-boiling liquid which is in a gaseous state at room temperature and atmospheric pressure, is introduced between the mass and the walls of the cavity. The coolant is discharged from the cavity through at least one controllable cross-section outlet to regulate the contact time between the coolant and the mass. The initially set precooled body is ejected from the mold and is subjected to final cooling and temperature homogenization (tempering), e.g. in a liquid bath.

Abstract: Unitary molded plastic hinged article and method of making in which a fluid molten mixture of heat softenable resin and a blowing agent in substantially unfoamed condition is introduced into an expandable mold cavity to fill the cavity and the mold is expanded to allow foaming of the resin to form at least one foam cored article section while the resin adjacent the mold surface is still fluid and in which the hinge structure is formed by a member adapted to form a thin, flex portion and portions transitional from the thickness of the flex portion to the thickness of a cored article section, the shaping member being slidably disposed in an aperture in the mold with portions of the walls of the aperture exposed within the mold cavity at the time the molten mixture is introduced and the exposed portions of the walls being wiped by the shaping member when the mold is expanded.

Abstract: A tough board of thermoplastic resin foam provided with skin layers on both surfaces thereof and formed of large cells elongated in the direction of the thickness of said board, wherein an intermediate high density layer thicker than 0.1mm lies substantially halfway between the upper and lower surfaces of said board. The board is formed by extruding thermoplastic resin containing dissolved foaming agent as a sheet, cooling the upper and lower surfaces rapidly to form solid skin layers and then slowly cooling while allowing controlled expansion thereof between expansion restricting members.

Abstract: A process for producing cork lines which comprises holding a leader or lers with a pair of metal molds having at the junctional surfaces thereof one or more cavities for forming a float or floats and one or more furrows formed so as to pass through said cavity or cavities for holding said leader or leaders, injecting a molten synthetic resin mixed witha foaming agent into said cavity or cavities to effect molding and foaming of said resin, cooling said metal molds and taking out a flat or floats integrally fixed to said leader or leaders from said metal molds.

Abstract: Foam insulated conductor is produced by heating the conductor to a temperature at which the conductor retains sufficient heat to effect crosslinking and foaming of a polymer composition, followed by extruding the polymer composition onto the conductor, with the crosslinking and foaming being effcted by the retained heat.

Abstract: Disclosed is a method for continuous extrusion coating of a hollow core material with a highly expanded polyolefin resin, which is characterized by subjecting an extruded molten mass of an expandable polyolefin resin to external cooling at the point at which said molten mass begins to foam and supplying said hollow core material with the surface temperature thereof kept below the softening point of said polyolefin resin for thereby enhancing the fastness of adhesion of the highly expanded polyolefin foam with the hollow core material and at the same time facilitating the release of the two materials thus joined.

Abstract: A method of forming a ball core is disclosed. A flowable homogeneous mass of a thermoplastic resin and a blowing agent is injected into the spherical cavity of a mold under temperature and pressure conditions sufficient to activate the blowing agent. The mold is cooled to 32.degree. to 65.degree. F. so as to form a skin on the surface of the mass. The mass is held within the mold cavity for a sufficient time so that the skin has adequate strength to prevent its rupture by blowing agent contained within the mass, upon removal of the mass from the mold cavity. The mass is cooled at an exterior temperature of 32.degree. to 65.degree. F. A ball core for baseballs and softballs is also disclosed.

Abstract: The instant invention is directed to novel mold release agents for polyurethane resins and to the use thereof, particularly in the closed mold forming of polyurethane foams. The mold release agents disclosed herein are applied to the surface of the mold prior to molding and broadly comprise talc dispersed in an emulsion of water and an organic solvent.

Abstract: Foamable synthetic resin materials are plastified and injected into a mold cavity in an amount less than the volume of mold cavity and a body of gas under pressure is charged in the mold cavity in such manner that it is enclosed by said resin materials. When the injected resin materials sets at least at its outer surface layer, the gas is discharged out of the mold cavity so that the foamable resin materials can be expanded in the hollow portion formed by the pressure of the charged gas. Said foamable resin materials may be surrounded by unfoamable resin materials in the mold cavity.

Abstract: An injection molded polymer having limited surface gloss is provided by preparing an admixture of an injection moldable polymer substrate and an additive chosen from among the group consisting of finely divided textile fibers, finely divided hydrocarbon polymers, and blowing agents and injection molding an article from the admixture. In the embodiment of the invention employing blowing agents the admixing is carried out at a temperature below that at which the blowing agent is activated and the injection molding is carried out at a temperature sufficient to activate the decomposition of the blowing agent.

Abstract: A rigid, dimentionally stable, distortion-free article of foamed polyvinyl aromatic resin, having a solid outer skin, is formed by incorporating in a foamable polyvinyl aromatic resin a finely, divided inert solid that has been surface treated to render the solid hydrophobic and then molding the foamable composition under foaming conditions. Foamed polyvinyl aromatic resin articles molded in accordance with the present invention have physical dimensions capable of meeting tolerances in the order of .+-. 0.002 inches and are suitable for use in the manufacture of precision measuring devices and, particularly, frames for level instruments.

Abstract: Plastic blown ware is made by expanding a molten plastic tubular blank into contact with the wall of a mold cavity. This invention evacuates air from the part of the cavity around the outside of the blank to increase the pressure differential across the tube wall during the blowing period and to help prevent the plastic from pulling away from the cavity wall during cooling and shrinkage. The invention makes blown ware by compounding the plastic with a blowing agent and by controlling the bubble size and wall thickness by changing the pressure on opposite sides of the blown article to whatever pressure will permit the gas bubbles and the plastic to expand to the desired size during cooling and setting of the plastic.

Abstract: An impact energy-absorbing, relatively low density, urethane foam for use in automobile bumpers has a high content of urea linkages and is relatively temperature insensitive, i.e. gives approximately the same physical performance over a wide range of temperature. The foam is water blown in a closed mold from a quasi-prepolymer system. The pack factor is preferably in the range of 1.5 to 8 and the molded density is in the range of 5 to 20 lbs./ft..sup.3.The foam formulation is based on a polyol of a poly (oxypropylene/ethylene) triol reacted with a styrene/acrylonitrile monomer mixture which triol thus modified is reacted with (1) a 50 to 150 equivalent weight polyol cross linker of 2 to 6 functionality, (2) a MDI or TDI/glycol or triol quasi-prepolymer and (3) some water.

Abstract: A method of producing foamed thermoplastic resin articles having smooth and glossy surfaces free from swirl marks and hair cracks, which comprises melting a thermoplastic resin containing a condensable blowing agent and an organic chemical blowing agent, injecting, in full shot, the molten resin into a mold cavity to which a pressurized gas is being applied during said injection, terminating the application of the pressurized gas to the mold cavity, enlarging the volume in said molded cavity by movement of a mold wall, and thereafter cooling and solidifying the resin to form the foamed articles.

Abstract: A method of injection molding foamed articles wherein, after the mold is closed and while the mold is held closed, a gas counterpressure is generated within the mold cavity against which a portion of the foamable resin is injected under a pressure which prevents foaming. Thereafter, a shape-forming element adapted to be retracted to be flush with a wall of the mold cavity in the final phase thereof, is advanced to force the nonfoamed material, still against the gas counterpressure, into the remainder of the cavity. After a skin has formed, on the mass within the mold cavity the latter element is retracted to permit foaming, preferably after foaming has been initiated by allowing a portion of the foamable mass to recede into the injection cylinder during the inception of the foaming process.

Abstract: A method for producing foamed thermoplastic resin profiles with an outer skin layer of increased hardness and an inner foam structure which may be used in place of wooden articles. The outer skin has a smooth surface and a good appearance, and the inner portion enclosed by the skin has a uniform foam structure. Also, with this method an improved foaming efficiency can be obtained.

Abstract: A pipeline retard, support, and protection method wherein a fast-setting, expandable, organic spray foam is sprayed at spaced locations in a trench to create support pads and retards in the trench. The foam constituents are mixed in a spray apparatus and directed as a spray foam into the trench where it rapidly expands and stiffens into a layer of foam. Rapid expansion and corresponding rapid stiffening is believed to cause the cells in each layer of the foam structure to be elongated essentially normal to the plane of the layer. This cellular configuration in each layer imparts vertical strength and limited lateral flexibility to the structure. A plurality of layers of foam are sequentially formed in the trench to fabricate the desired structure. The placement of each layer is sequenced so as to permit a membrane to form on the surface of each layer for improved strength and inhibition of water penetration.