Abstract: A method for making low density (0.8-2 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent, the process emitting blowing agent during processing in an amount of from only about 0.3 to about 2.5 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commerically viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: The invention relates to an azeotrope with a minimum boiling point, capable of being employed as a refrigerating fluid replacing trifluorobromomethane (Halon 1301) in industrial refrigeration systems at very low temperature with single-stage compression.The azeotrope according to the invention is a mixture of 1,1,1-trifluoroethane (HFA 143a) and of propane (R290). At the normal boiling point (approximately -53.4.degree. C. at 1.013 bars), its 1,1,1-trifluoroethane content is approximately 70.6 mass % and that of propane 29.4 %.This azeotrope can also be employed as an aerosol propellant or as a blowing agent for plastic foams.

Abstract: The polymerization in aqueous suspension of at least one vinylaromatic monomer is carried out in the presence, relative to the vinylaromatic monomer, of approximately 0.01% to 0.06% by weight of at least one polyethylene wax and of approximately 0.005% to 0.1% by weight of at least one nonionic surface-active agent which has an HLB value of between 7 and 16.Materials obtained from expandable beads prepared according to this polymerization process.

Abstract: Foam sheets of high heat distortion resistance contain a) from 80 to 99% by weight of a styrene polymer and b) from 1 to 20% by weight of poly(2,6-dimethyl-1,4-phenylene oxide), and, if desired, conventional additives and are produced by extrusion using a low-boiling blowing agent.

Abstract: Novel, expandable polymeric blends comprising at least one vinylaromatic monomer-acylonitrile resinous material, an effective amount of at least one blowing agent, and from about 0.2 to about 1.0 percent by weight, based on the weight of resinous material, of an expansion aid consisting essentially of triethylene glycol. The triethylene glycol expansion aid unexpectedly reduces the amount of expansion agent required to expand the composition, particularly to low density products, without adversely affecting the final properties of the foamed product.

Abstract: Disclosed is an extruded, low density, non-outgassing ethylenic polymer foam containing 30-85% open cells and the remainder closed cells and having an essentially integral surface. The foam possesses superior compression recovery and lower compression resistance when compared with similarly comprised ethylenic closed cell foams and superior moisture resistance and handling characteristics when compared to open cell foams.

Abstract: A process for making high-purity foam moldings without the use of organic blowing agents involves the use of inorganic gases such as carbon dioxide, nitrogen, air and other pneumatogens.The process involves the simultaneous impregnation and purification of the polymers with or without foaming. If foaming is not done in the extractor, the polymeric particles can be foamed in pre-expanders or expanded and molded in downstream equipment.

Abstract: Foam particles of propylene polymers which have shrunk from 40 to 95% of their original volume and have a bulk density of from 10 to 30 g/1 can be expanded if they are treated with air or nitrogen under superatmospheric pressure, subsequently decompressed. If desired post-foamed by heating and, after aging, re-treated with air or nitrogen under superatmospheric pressure, subsequently decompressed and aged under atmospheric pressure until the pressure in the cells has dissipated.

Abstract: A biodegradable shaped product comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a biodegradable packaging material comprising an expanded, low density, closed cell starch product, the starch having at least 45% by weight amylose content and the expanded product having a bulk density of less than about 2.0 lb/ft.sup.3, a resiliency of at least about 50%, and a compressibility of from about 100 to 800 g/cm.sup.2.

Abstract: A biodegradable shaped product comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a biodegradable packaging material comprising an expanded, low density, closed cell starch product, the starch having at least 45% by weight amylose content and the expanded product having a bulk density of less than about 2.0 lb/ft.sup.3, a resiliency of at least about 50%, and a compressibility of from about 100 to 800 g/cm.sup.2.

Abstract: A process for producing expandable thermoplastic resin beads which comprises suspending in an aqueous medium interpolymer beads comprising a polyphenylene ether resin and a polymerized vinyl aromatic monomer such as styrene, polymerizing the vinyl aromatic monomer in the presence of a polymerization catalyst to interpolymerize the vinyl aromatic monomer with the polyphenylene ether and, optionally, adding a cross-linking agent, to form interpolymerized thermoplastic resin beads, and introducing a blowing agent under pressure into the thermoplastic resin beads. The resulting resin beads have excellent foamability and molding fusability, and a foamed shaped article having superior thermal stability can be prepared from these beads.

Abstract: Foams having high compressive strength are obtained by extrusion of a mixture of a styrene polymer and from 3 to 9% by weight of a blowing agent consisting of from 80 to 100% by weight of CO.sub.2 and from 0 to 20% by weight of one or more halohydrocarbons or hydrocarbons which are gaseous at room temperature, the mixture being extruded into a zone under from 0.1 to 2 bar gage pressure and the foam being allowed to stabilize under this pressure.

Abstract: A process for manufacturing expandable polystyrene pellets having a bulk density of about 36 lbs/cubic foot which upon expansion results in expanded articles having a bulk density of about 0.8 lbs/cubic foot and having substantiallly uniform cell formation is an interior portion thereof.

Abstract: Volatile substances in polyphenylene ether or polyphenylene ether/polystyrene compositions are substantially reduced by extruding the resins in a single pass using a plurality of stages including water injection and vacuum venting.

Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.

Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.

Abstract: A process for producing expandable thermoplastic resin beads which comprises suspending in an aqueous medium interpolymer beads comprising a polyphenylene ether resin and a polymerized vinyl aromatic monomer such as styrene, polymerizing the vinyl aromatic monomer in the presence of a polymerization catalyst to interpolymerize the vinyl aromatic monomer with the polyphenylene ether and, optionally, adding a cross-linking agent, to form interpolymerized thermoplastic resin beads, and introducing a blowing agent under pressure into the thermoplastic resin beads. The resulting resin beads have excellent foamability and molding fusability, and a foamed shaped article having superior thermal stability can be prepared from these beads.

Abstract: This invention relates to preparation of polyamide-imide foam by extruding foamable composition comprising polyamide-imide and volatiles into a confined expansion zone, expanding the composition therein and cooling the result. The resulting foams are essentially open-celled and exhibit good strength, insulating properties and other desirable features.

Abstract: The invention comprises a blowing agent composition useful in the production of insulating styrenic foams comprising ethylchoride, propane and a halogenated ethane selected from the group consisting of 1,1,1-trifluoro-2-fluoroethane, 1-chloro-1,1-difluoro-2,2,2-trifluoroethane 1-chloro-1,1-difluoroethane (FC-142b) and mixtures thereof. The invention further comprises a method to produce dimensionally stable insulating styrenic foams using the blowing agent composition. The blowing agent composition has a significantly reduced ozone reactivity potential compared to previous commercial styrenic foam blowing agents.

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: Cured polyimide foam is exposed to an atmosphere of steam at elevated temperature and pressure for a period of time sufficient to convert the foam into a non-flexible, non-resilient recurable cellular material. Preferably the process is conducted such that the cellular material is recurable to a flexible resilient foam having tensile strength properties similar to the tensile strength properties of the original cured polyimide foam subjected to the process. Before recuring, the non-flexible, non-resilient recurable cellular material may be shaped or contoured, and then recured. For example, by impressing shaped articles into the recurable material followed by recuring, shipping/storage containers for the articles are readily produced.

Abstract: The invention relates to polyethylene compositions comprising 20-98 wt. % branched polyethylene (a) with a density of between 915 and 940 kg/m.sup.3 and a melt flow index of between 0.05 and 40 dg/minute, prepared by a high pressure radical process, and 2-80 wt. % substantially linear polyethylene (b) with a density of between 850 and 915 kg/m.sup.3, a melt flow index of between 0.05 and 25 dg/minute and a DSC crystallinity at 23.degree. C. of at least 10%, prepared with the aid of a transition metal catalyst, the difference between the highest crystallization temperature of branched polyethylene (a) and the highest DSC crystallization temperature of linear polyethylene (b) being at most 10.degree. C. and the mixture having a modulus of elasticity of at most 280 N/mm.sup.2 and objects made therefrom. These polyethylene compositions, when processed to foamed objects, have a high resistance to high temperatures as well as a high flexibility.

Abstract: The process of enabling foam moldings to expand further than otherwise by impregnating the expanded sheet with inorganic gases such as carbon dioxide, nitrogen, air and other pneumatogens prior to reheating to effect expansion.

Abstract: A method of making thermal insulating products comprising porous, lightweight, high temperature resistant inorganic particles in a polyimide foam matrix and the product thereof. A polyimide precursor powdered is mixed with about equal weight of flake-like porous inorganic particles to substantially uniformly coat the particles with powder. The mixture is placed in a mold and compressed slightly. The assembly is heated to the foaming temperature of the polyimide precursor for a period suitable to produce uniform foaming. Then the temperature is raised to the curing and crosslinking temperature of the precursor for a time period sufficient to produce complete cure. A high temperature and flame resistant, light weight, highly insulating product results. If desired, protective sheets of material may be bonded to selected product surfaces during or after the molding operation.

Abstract: A volatile foaming agent for thermoplastic foam is a blend of about 65 to 75 weight percent chlorodifluoro-methane and from about 25 to 35 weight percent pentane.

Abstract: A method of manufacturing lightweight shapes from polyimide foam in which density discontinuities such as cavities, varying cell size, or swirl marks are substantially eliminated. A block or bun of polyimide foam is prepared in a conventional manner which results in a high density rind and other discontinuities. The foam is chopped into fine flakes in a chopper with a continuous flow of air to prevent electrostatic attachment of the flakes to the chopper and ducting. The flakes are mixed with a quantity of polyimide precursor and then heated to cause the precursor to bond the flakes into a uniform mass having highly uniform and predictable density. This is a very economical process since portions of the original bun may be used which would ordinarily be discarded. An alternative method is described whereby the flakes can be bonded together by using the precursor in the form of a partially cured foam either as a binder, or by making the flakes of partially cured foam.

Abstract: A process for the production of optionally foamed moldings having a compact surface by the reaction in closed molds of a mixture of(a) organic polyisocyanates,(b) compounds containing isocyanate-reactive groups and having a molecular weight of 62 to about 10,000 and(c) mold release agents based on salts of (i) saturated or unsaturated aliphatic or cycloaliphatic carboxylic acids or carboxylic acid mixtures containing (on a statistical average) at least 8 carbon atoms per molecule and (ii) tertiary amines,characterized in that the release agents (c) used are salts in which the amine component (ii) is based on tertiary monoamines or mixtures of tertiary monoamines corresponding to the following formula ##STR1## in which R.sub.1 represents a saturated or unsaturated aliphatic hydrocarbon radical containing at least 12 carbon atoms and R.sub.2 and R.sub.

Abstract: Alkenyl aromatic thermoplastic synthetic resinous elongate foam bodies having a machine direction, a traverse direction and closed noninterconnecting gas-containing cells are prepared using 1,1-difluoro-1-chloroethane as a blowing agent. These foam bodies have an average cell size of 0.05 to 2.0 millimeters, a minimum cross-sectional dimension of at least 0.25 inch, a cross-sectional area of at least 8 square inches, a water vapor permeability not greater than 1.8 perm inch, a density not exceeding 2.4 pounds per cubic foot, and an absolute dimensional stability of less than 4 percent in any direction when measured by the test designated ASTM D2126/C578. Also disclosed is a method for preparing such foam bodies, other alkenyl aromatic thermoplastic synthetic resinous elongate foam bodies having the same criteria, except a density from 2.4 to 5.0 pounds per cubic foot and a method for preparing such greater density foam bodies.

Abstract: The process of making foam moldings without the use of organic blowing agents involves the use of inorganic gases such as carbon dioxide, nitrogen, air, solid carbon dioxide and other pneumatogens. Because of the rapidity with which these gases diffuse out of the polymer particles, it is necessary to pre-expand the particles and then reimpregnate the particles with the same or different gas.

Abstract: Polyolefin foams which have a density of from 30 to 300 g/l, do not exhibit after-shrinkage and possess taut cells are prepared by letting down a polyolefin/blowing agent gel, the latter first being let down to 0.1-10 bar gage pressure and the foam being kept at this pressure until it has cooled to at least 20.degree. C. below the expansion temperature.

Abstract: The use in otherwise conventional polyolefin extrusion foaming process of a stability control agent, in conjunction with certain binary or tertnary mixed blowing agent systems containing 1,2-dichlorotetrafluoroethane provides closed-cell olefin polymer foam articles having increased maximum cross-sections, smooth skins and good dimensional stability.

Abstract: A method and apparatus are provided for producing a mixture of plastics materials which are capable of being foamed with propellants. The method permits plastics materials, which require considerably different processing conditions, to be fused, homogenized and mixed with a propellant in an extruder. By feeding a high-molecular weight high-temperature resistant plastics material into the extruder through a first feed opening and subsequently feeding a low-molecular weight, low-temperature-resistant plastics material into the extruder through a second feed opening disposed downstream of the first feed opening but where the first plastics material is in a fused and homogeneous state and by introducing the propellant through a third feed opening downstream of the second feed opening, the desired homogenisation of the two plastics materials and propellant is ensured.

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: Described are ways of improving the yields of specification grade polyimide foam on a consistent basis from one run to the next, by use of improved microwave-based foaming processes. In one such process, the microwave radiation is directed upon the top, sides and ends of the body of polyimide precursor and of the foam structure as it is developing, but the extent to which such radiation impinges upwardly into the bottom of said body and said foam structure is curtailed, preferably by means of a metallic shield located below the precursor and developing foam structure. Mechanisms by which the shields function to provide the improvements of the process are discussed, and methods based thereon are set forth.

Abstract: A process for producing expandable thermoplastic resin beads which comprises suspending in an aqueous medium interpolymer beads comprising a polyphenylene ether resin and a polymerized vinyl aromatic monomer such as styrene, polymerizing the vinyl aromatic monomer in the presence of a polymerization catalyst to interpolymerize the vinyl aromatic monomer with the polyphenylene ether and, optionally, adding a cross-linking agent, to form interpolymerized thermoplastic resin beads, and introducing a blowing agent under pressure into the thermoplastic resin beads. The resulting resin beads have excellent foamability and molding fusability, and a foamed shaped article having superior thermal stability can be prepared from these beads.

Abstract: The present invention discloses a vinylidene chloride resin type in-mold foam molding having a broad cross-sectional area and a free shape, which is useful as thermal insulating plate materials or as anti-shock molded vessels, and also to foam particles, which are or expandable particles convenient for the preparation thereof. The present invention is also related to a series of advantageous foaming techniques for completion of such a molding.

Abstract: A biodegradable packaging material comprising an expanded high amylose starch product having at least 45% by weight amylose content, said expanded product having a low density, closed cell structure with good resilience and compressibility.Another embodiment provides a method of preparing a low density, biodegradable packaging material comprising extruding a starch having at least 45% by weight amylose content, in the presence of a total moisture content of 21% or less by weight, at a temperature of from 150.degree. to 250.degree. C.

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 low density extruded structural foam of closed cell structure having good compressive strength comprising a engineered thermoplastic resin, alone, or containing a flame retarding agent and/or nucleating agent, optionally combined with a vinyl aromatic resin, and a blowing agent is produced by feeding said resin, or composition, into a primary extruder wherein mixing, adding a blowing agent which is essentially insoluble in the resin at room temperature but soluble in the melt and further mixing, then optionally passing the mixture to a second, cooling extruder, passing said extruded mixture through a die, then expanding and foaming said composition into a foam article.

Abstract: The present invention is directed to a polyisocyanate comprising the reaction product of(a) an isocyanate selected from the group consisting of methylenebis(phenylisocyanate), polymethylenepoly(phenylisocyanate), and mixtures thereof, and(b) a polyester polyol having a hydroxyl functionality of from 2 to 3 and a molecular weight of from about 750 to about 3500, said polyester polyol prepared by reacting neopentyl glycol and adipic acid,the isocyanate group content of said reaction product from about 14% to about 28% by weight. The invention is also directed to a RIM process using such prepolymers.

Abstract: A foam of a polyolefin/polystyrene resin mixture obtained by mixing a polyolefin resin and a polystyrene resin in the presence of a hydrogenated styrene/butadiene block copolyer, and subjecting the resultant mixed resinous composition to extrusion foaming, wherein;(1) said hydrogenated styrene/butadiene block copolymer comprises, as components before hydrogenation, 10 to 38% by weight of styrene and butadiene with a content of 1,2-bond type butadiene of 20 to 50% by weight based on butadiene, and;(2) said foam comprises a thin surface skin portion showing a value of 0.65 or more of the surface structural index S represented by the following formula:S=t/T.gtoreq.0.65wherein t and T each represent a total light-transmission evaluated according to the method of ASTM D1003 with respect to a surface skin layer and an inner layer of the foam,is found to have the cushioning properties (or the foam properties) that enables elastic cushioning of a large load.

Abstract: Cups have been molded from expandable styrene polymer particles having a portion or all of the blowing agent replaced by isopentane. Cups molded from these beads were coffee leak tested and generally exhibited enhanced retention of coffee.

Abstract: Closed-celled foams of high compressive strength are obtained by extruding a mixture of a styrene polymer and from 8 to 16% by weight of a blowing agent mixture containing from 2 to 20% by weight of ethyl chloride, from 2 to 20% by weight of carbon dioxide, from 20 to 80% by weight of dichlorodifluoromethane and from 10 to 60% by weight of monochlorodifluoromethane.

Abstract: A multicolored foam product and a method for the preparation thereof. Heat-plastified foamable gel of a thermoplastic resin or resins containing blowing agents are combined with different coloring materials added sequentially and extruded through an orifice of a die which is extended in length to facilitate laminar flow in the resin. This resin is expanded to form a multicolored layered foam product, such as multicolored foam planking, in a single extrusion. Multicolored foam planking produced is suitable for use as the body material for surfboards, body boards, and other recreational products.

Abstract: According to a method of manufacturing a foamed polypropylene resin sheet of this invention, a composition comprising as a resin component a mixture of 80 to 20 wt % of a crystalline propylene-ethylene block copolymer containing 20 wt % or less of ethylene and having a melt index (MI) of 2 or less and 20 to 80 wt % of a crystalline propylene-ethylene block or random copolymer containing 5 wt % or less of ethylene and having an MI of 6 to 20 or a polypropylene homopolymer having an MI of 6 to 20 is used. A pair of molding roll dies is horizontally arranged at a point separated from the center of an apex of an extrusion foaming die when a foamed sheet is to be extrusion-molded. A distance between the center of the roll and the apex of a base lip is set to fall within a range of (R.sup.2 +25).sup.1/2 to (R.sup.2 +144).sup.1/2 where R is a radius of the molding roll die.

Abstract: The present invention provides that, in a process for production of foamed articles of a polyproplene resin which comprises compressing pre-expanded beads of propylene resins under a gaseous pressure, filling a mold capable of closing but incapable of sealing with the compressed beads, then venting from the mold and heating and fusing with steam thereby to produce the molded article in the shape of the mold, the improvement wherein the pre-expanded beads of the polypropylene resins having two melting points when measured by differential scanning calorimetry and having a quantity of the peak fusion heat QH based on a melting point at a high temperature peak of the two melting points being 0.3 to 3.5 cal/g are introduced compressively into the mold so that a compressive rate is 10 to 60%.

Abstract: Improved closed cell foams particularly suitable for use in packaging applications comprising a plurality of coalesced strands or profiles of a foamed thermoplastic composition.

Abstract: This invention relates to a method and apparatus for improving not only the quality of the production of molded foamable thermoplastic resin particles converted into fusion-bonded materials but also the output by protecting the resin from atmospheric pressure by pressurizing the particles and heating the particles to soften the same.

Abstract: A method is disclosed of making dimensionally stable, expanded polystyrene foam patterns comprising: (a) expanding a supply of beads comprised of polystyrene and a thermally responsive expanding agent, the expansion being accomplished in one or more stages by use of a gaseous heating agent (steam) to define a fused pattern body of the expanded beads, and (b) subjecting the fused pattern body to subatmospheric pressure (in the range of 5-20" of Hg) for a period of about 0.5-6 hours but no more than sufficient to accelerate and complete the migration of the trapped expanding agent out of the pattern body. The expanding agent can be selected from the group consisting of various forms of pentane or butane.

Abstract: The present invention is directed to a process for the production of polyurethane moldings by reacting a reaction mixture comprising(a) an organic polyisocyanate(b) a compatible polyol blend comprising(i) at least one polyether polyol having a hydroxyl functionality of from 2 to 8, and a molecular weight of from 350 to below 1800, and(ii) at least one hydroxyl functional organic material containing from 2 to 8 hydroxyl groups and having a molecular weight below 350, components (i) and (ii) being used in a weight ratio of component (b)(i) to (b)(ii) of from about 10:1 to about 1:10, and(iii) no more than 45% by weight based on the weight of component (b) of an active hydrogen containing compound having a molecular weight of 1800 or more,said reaction mixture being processed as a one-shot system by the RIM process at an isocyanate index of from about 70 to about 130.