Abstract: A one-part activator and blowing agent system for foaming plastics comprising an alkali metal borohydride and a salt hydrate blended in a single pellet or as separate pellets with a dry inert resinous polymer carrier. The one-part system is blended with a resinous polymer and then the blend extruded at a temperature at which the blend becomes molten such that the salt hydrate releases its water of hydration to hydrolyze the borohydride and produce a cellular article.

Abstract: There are provided methods for making heat-resistant, foamed, crystalline plastic materials. For example, polyethylene terephthalate may be foamed with a polycarbonate, extruded into a foamed sheet and this foamed sheet may be thermoformed by being subjected to crystallization annealing. The thermoformed, foamed, crystalline plastic sheets prepared by this process are particularly useful for forming light weight, ovenable food containers.

Abstract: There are provided heat-resistant, foamed, crystalline polyesters, such as polyethylene terephthalate foamed with a polycarbonate and subjected to crystallization annealing, which are particularly useful for forming light weight, ovenable food containers.

Abstract: A molded object having a sponge-like interior surrounded by a skin, molding composition from which it is produced, and the method for producing the article. Copolymers of vinyl-substituted aromatic compounds containing from 8-18 carbon atoms copolymerized with conjugated diene having from 4-12 carbon atoms and polymer chosen from among solid resinous polymers of vinyl-substituted aromatic compounds present in amounts ranging from about 10 to about 75 parts by weight per 100 parts by weight of the copolymer and solid resinous copolymers of ethylene present in an amount of about 5 to about 50 parts by weight per 100 parts by weight of the copolymer are blended with a sufficient amount of polarizing agent to achieve rapid heating through response to microwave treatment, blowing agent in an amount sufficient to provide a sponge-like, rubbery porosity to an article molded therefrom, and, optionally, cellular control agent.

Abstract: Dielectrically heatable polyolefin foams which contain from 3 to 20% by weight of an unsaturated polyester being optionally fully hardened.

Abstract: A crosslinked foam having an expansion ratio of 25 to 60 which comprises a composition containing 100 parts by weight of a resin component consisting of an ethylenevinyl acetate copolymer or a mixture thereof with a thermoplastic resin and 50 to 500 parts by weight of an inorganic powder material.

Abstract: A process for obtaining cellular materials from unsaturated polyester resins reinforced with fillers having a density below 0.7 kg/lt by injecting a liquid foam, made from the resins by mechanical introduction of a gas therein into a closed mold, is described. The liquid foam, obtained from polyester resins including additives and optionally a reinforcement of synthetic, artificial, vegetable or mineral fibres having a length lower than 5 mm, and optionally containing a low boiling foaming agent, is injected voluminized and cross-linked in the hot or in the cold in a closed mold containing a reinforcing agent of synthetic, artificial, vegetable or mineral fibers as a monofilament mat, a cut fibre mat, a mono or bidirectional roving woven mat, rovings, fabrics.

Abstract: Disclosed herein is a process for producing cross-linked polypropylene by subjecting a homogenous mixture of a polypropylene with from about 2 to about 20 weight percent, based upon the weight of the polypropylene, of polybutadiene with a molecular weight of from about 500 to about 10,000 to conditions sufficient to effect cross-linking, for example, through the use of cross-linking agents and/or irradiation. In addition, the process disclosed herein may be utilized to produce cross-linked and foamed polypropylenes.

Abstract: New rigid polyvinyl chloride foam having a density of less than 200 kg/m.sup.3 and having a uniform, fine-celled cell-structure consisting of a rigid vinyl chloride homopolymer containing per 100 parts by weight of polyvinyl chloride 0.1-15 parts by weight of a homo- or copolymer of an alkyl methacrylate having an alkylgroup of 1-10 carbon atoms having a viscosity of the solution .eta..sub.0.1 of between 1.times.10.sup.-6 and 4.times.10.sup.-6 m.sup.2 /s measured at 293 K in 1,2 dichloro ethylene and a method for the preparation of such a new rigid polyvinyl chloride foam.

Abstract: New rigid polyvinyl chloride foam having a density of between 10 and 50 kg/m.sup.3 and having a uniform, fine-celled cell-structure consisting of a rigid vinyl chloride homopolymer containing per 100 parts by weight of polyvinyl chloride 0.1-15 parts by weight of a homo- or copolymer of an alkyl methacrylate having an alkyl group of 1-10 carbon atoms and a method for the preparation of such a rigid polyvinyl chloride foam.

Abstract: The invention provides a flame retardant thermally insulating material which comprises cellular polymer particles and fly ash bound into a coherent mass by a dried synthetic polymer latex binder, and a process for providing between at least two spaced-apart surfaces a flame retardant thermal insulation in the form of such a material. The process has particularly useful application in the field of roof insulation in sloping roofs having spaced-apart outer and inner layers.

Abstract: Disclosed are low density foam planks of ethylenic polymers, which planks have a density of from about 0.8 to about 1.6 pounds per cubic foot, dimensional stability, substantially closed-cell structure, a cross-sectional area of at least six square inches and a minimum cross-sectional dimension of at least 0.5 inch. Such foam planks are made from polyethylene resins (e.g., low density polyethylene) by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises at least one polyethylene resin and at least one volatile blowing agent. The process of making such foam planks is particularly characterized by the improvement wherein the flowable gel is mixed sufficiently to disperse the blowing agent in the gel to an amount from about 13.5 to 35.times.10.sup.4 moles per gram of the ethylenic polymer and such process is especially beneficial in that it enables the preparation of substantially closed-cell polyethylene foams having densities of from 0.

Abstract: An insulating composition comprising in combination a liquid binder, a heat expanded polystyrene material in bead or granular form and a reinforcing pigment, said liquid binder comprising a 95.5 to 50:50 mixture, by weight of an acrylic or vinyl polymer emulsion and an alkali metal silicate, said expanded polystyrene being present in an amount ranging from 5 to 25 percent by weight of said composition.

Abstract: Disclosed are low density foam planks of ethylenic polymers, which planks have a density of from about 0.8 to about 1.6 pounds per cubic foot, dimensional stability, substantially closed-cell structure, a cross-sectional area of at least six square inches and a minimum cross-sectional dimension of at least 0.5 inch. Such foam planks are made from polyethylene resins (e.g., low density polyethylene) by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises at least one polyethylene resin and at least one volatile blowing agent. The process of making such foam planks is particularly characterized by the improvement wherein the flowable gel is mixed sufficiently to disperse the blowing agent in the gel to an amount from about 13.5 to 35+10.sup.-4 moles per gram of the ethylenic polymer and such process is especially beneficial in that it enables the preparation of substantially closed-cell polyethylene foams having densities of from 0.

Abstract: Composition of matter adapted to be foamed into essentially a closed cell structure, preponderance of the cells being less than 500 microns in size and containing a chlorofluoroalkane of 1 to 2 carbon atoms, said composition comprising chlorinated polyvinyl chloride resin, and effective amount of a blowing agent, an effective amount of a nucleating agent, and 5 to 20 parts of a processing aid per 100 parts of said resin, said processing aid has a dilute solution viscosity of greater than 2.5 and is selected from copolymers of styrene and acrylonitrile containing 10 to 40% of acrylonitrile.

Abstract: Substantially closed-cell aliphatic olefin polymer foams having improved dimensional stability are provided by the inclusion therein of from 0.1 to 10 weight percent, based upon the olefin polymer, of certain naphthyl amine compounds.

Abstract: Improved polymeric foams are obtained by the introduction of a beneficial additive to the system by dissolving said additive into a liquid foaming agent which is a solvent therefor, combining the solution with the polymer and extruding the polymer in foamed form.

Abstract: Composition of matter that can be foamed to form an expanded product having density of less than 20 lbs/ft.sup.3 and containing a preponderance of the cells in the size range of less than 500 microns comprising a mixture of chlorinated polyvinyl chloride, 5 to 50 parts by weight of the chlorofluoroalkane of 1 to 2 carbon atoms as a primary blowing agent and 0.01 to 2 parts by weight of azodicarbonamide that is dispersed through the resin and forms cell nuclei from which expanded cells are created, all based on 100 parts by weight of the resin.

Abstract: An elastomeric or thermoplastic polymer, such as polyethylene, is mixed with silane for grafting onto the polyethylene; after grafting the material is extruded around a cable, a conductor, tubing or the like, but just prior to extrusion moist nitrogen is forced into the extruder so that the material will expand to foam, the cells being filled with moist gas so that the cell walls crosslink to stabilize the resulting foam sheath.

Abstract: The dimensional stability of relatively unstable substantially closed-cell low density foams of non-ionic ethylenic polymers (e.g., polyethylene, ethylene/vinyl acetate copolymers, etc.) can be notably improved by the incorporation therein (during the preparation thereof) of from about 5 to about 95 weight percent (based on total polymer weight) of a copolymer of ethylene with from about 3 to about 45 weight percent of a monoethylenically unsaturated carboxylic acid.

Abstract: A blowing agent concentrate comprising a chemical blowing agent and a thermoplastic composition vehicle therefore, said thermoplastic composition being a saturated polyester and/or copolyester having a crystalline melting point between 100.degree. C. and 220.degree. C. and a reduced viscosity of 0.4 dl/g to 1.6 dl/g; the use of such blowing agent concentrate in the formation of foamed articles of high molecular weight polyalkyleneterephthalate which articles can be filled and/or reinforced and/or flame proofed and can contain other additives. Particularly contemplated is the use of such blowing agent concentrate in the formation of glass fiber reinforced structural foam moldings of polyalkyleneterephthalates especially polytetramethylene terephthalates.

Abstract: A process for the production of a foamed thermoplastic composition which comprises blending a minor amount of a foaming agent with a thermoplastic resin in an extruder and comminuting the resultant extrudate.

Abstract: Disclosed is a film or sheet product comprising a closed cell foam comprised of a mixture of low density polyethylene and at least one ethylene polymer containing polar groups, and, optionally, a crystalline olefin polymer in which the mixture contains from about 0.025 to 1 percent by weight of said polar groups. Also disclosed is a method of making this film or sheet product and a wall covering material based thereon.

Abstract: A process for the production of foam materials, particularly polyolefin foam materials, from crosslinked polyolefin scraps involves comminuting and compressing crosslinked polyolefin foam scraps at a temperature lying below the decomposition temperature of a crosslinked agent contained therein, plasticating the resulting comminuted product also at a temperature lying below the temperature of the crosslinked agent, forming a shaped article from the plasticated material and thereafter crosslinking and expanding the shaped article by heating above the decomposition temperature of the crosslinking agent and of a blowing agent contained within said material. The initial foam scraps are obtained during the formation of a crosslinked polyolefin foam containing material.

Abstract: The invention relates to a foamable polymeric polyblend of a matrix copolymer of alkenyl aromatic/alkenyl nitrile monomers having dispersed therein (1) a grafted diene rubber being grafted with said monomers and (2) an alkyl half ester of a styrene/maleic anhydride copolymer. The composition is foamed by the thermal decomposition of said half ester. The foamed polyblend has great utility as a structural foam with said composition providing fast molding cycles and fine cell structure. A method for foaming said polyblend is disclosed.

Abstract: Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resin blends having low stiffness by extrusion foaming, wherein the heat plastified gel comprises the ethylene polymer blend and at least one volatile blowing agent. The blends especially comprise a copolymer of ethylene and monoethylenically unsaturated carboxylic acid and a copolymer of ethylene and at least one monoethylenically unsaturated non-ionic comonomer. The starting ethylenic resin blends are preferably blends of ethylene acrylic acid copolymers and ethylene vinyl acetate copolymers, having stiffness less than about 20,000 psi. Exemplary volatile blowing agents are 1,2-dichlorotetrafluoroethane, 1-chloro-1,2,2,2-tetrafluoroethane and 2,2-difluoropropane.

Abstract: A process for producing a crosslinked and foamed resin sheet which comprises shaping a resinous mixture comprising a thermoplastic synthetic resin and a heat-decomposable blowing agent into a sheet form, applying a high-energy ionizing radiation to the resulting foamable resin sheet to crosslink the resin sheet, and then heating the resulting crosslinked foamable resin sheet to the decomposition temperature of the blowing agent or to a higher temperature; wherein the high-energy ionizing radiation has a range of at least 0.7 .rho.d g/cm.sup.2 in which d is the thickness in cm of the foamable resin sheet, and .rho. is the density in g/cm.sup.3 of the foamable resin sheet, and a low-energy ionizing radiation with a range of not more than 0.6 .rho.d g/cm.sup.2 in which d and .rho. are as defined is applied to the foamable resin sheet before, during or after the application of the high-energy ionizing radiation.

Abstract: A process for working up thermoplastic synthetic resin material, in particular unsorted thermoplastic synthetic resin waste material into an article having the working and processing properties of wood, and in which the material is subjected to a mixing operation in a housing including a screw member, and is fluidized, moulded, cooled in the mould, and removed from the mould. According to the invention, the synthetic resin material is supplied to an extruder without a screen member and without an extrusion nozzle, and kept therein until there is obtained a material that is fluid owing to temperature increase, and which material contains a gas when it leaves the extruder. The material is then passed into a mould having open ends, one of which is connected to the outlet of the extruder.

Abstract: A filament of a thermoplastic synthetic polymer having a plurality of adjacent, separate discontinuous cavities is made by a process wherein a silicone oil and an inert gas or gas-forming substance are dispersed in a polymer melt, and the melt is extruded into a filament. The melt contains up to and including 1% by weight of the silicone oil, based on the weight of the melt, at the time it is extruded and up to and including 10% by weight of an inert gas.

Abstract: A method of producing a low density polyethylene foam by extruding a melt blend containing polyethylene, an ionomer, a nucleating system and two expanding agents having substantially different vapor pressures and solubility in the melt blend.

Abstract: Foamed thermoplastic mixture of ionomers and polyolefin polymers are produced by extruding the mix together with a volatile blowing agent at elevated temperature and pressure. The density of the foamed products is from of 15 to 45 Kg/m.sup.3 and they satisfy the requirements of extrusion foamability, compressive strength or rigidity, thermal resistance and adhesion properties.