Abstract: A foamed isocyanate-based polymer having a cellular structure and containing a superabsorbent material, the polymer being capable of: (i) absorbing at least about 20 times its weight of an aqueous fluid maintained at a temperature of from about 20.degree. to about 25.degree. C., and (ii) retaining at least about 20 times its weight of absorbed aqueous fluid which is bound to the superabsorbent material. A process for producing a foamed isocyanate-based polymer comprising the steps of: providing a substantially uniform mixture comprising an isocyanate, an active hydrogen-containing compound and a superabsorbent material, the superabsorbent material being capable of absorbing at least about 20 times its weight of an aqueous fluid maintained at a temperature in the range of from about 20.degree. to about 25.degree. C.

Abstract: In this invention a new form of polytetrafluoroethylene has been found to be compression moldable to provide strong molded articles. It is also useful as an additive or strength binder. The new form is a compression molding powder comprised of comminuted, sheared particles of expanded porous polytetrafluoroethylene, said particles having a nudular-microfibrillar structure of irregular shape, and a mean particle size between 5 and 500 micrometers, and having a coating of a thermoplastic fluoropolymer on at least a portion of the particle. By irregular shape is meant that the nodes and fibrils do not have an ordered arrangement. The bulk density is about 0.06 to 0.2 g/cc.

Abstract: The present invention provides a method of reinforcing thin rigid plates. The method comprises applying, preferably by spray application, a curable composition onto one side of the rigid plate followed by curing the composition while only in contact with the rigid plate. The curable composition comprises: (i) a thermosetting resinous composition and (ii) expandable microspheres. The composition may optionally contain a particulate reinforcing material selected from the group consisting of milled glass fibers, milled carbon fibers, and mixtures thereof.

Abstract: In the present invention a blend of resin composition and blending technique is optimized to provide a desired balance of node size and fibril length with the additional property of thermal stability in the resulting stretched material.The stretched blend can be described as a polytetrafluoroethylene porous material having a microstructure of nodes interconnected by fibrils in which the material comprises a blend of two different polytetrafluoroethylenes, one polytetrafluoroethylene being a homopolymer of tetrafluoroethylene and the other polytetrafluoroethylene being a modified polymer of tetrafluoroethylene.

Abstract: The invention relates to a process for the production of expanded polyolefin beads by impregnating polyolefin particles with volatile blowing agents in a fluidized bed.

Abstract: The present invention relates to expandable styrene polymers containing recycled polystyrene, having a recycled material content of from 10 to 50% by weight, based on the total weight of the polystyrene, to which alkyldi(2-hydroxyethyl)amines have been added during the polymerization.

Abstract: There is provided a polytetrafluoroethylene (PTFE) porous material which has improved adhesion and improved buckling resistance on bending without a tearing problem along a tubular axial direction.The porous material is composed of a polytetrafluoroethylene and a heat-meltable resin of which melting point is lower than that of the polytetrafluoroethylene, has fibril portions and node portions and characterized in that the fibril portions are mainly of the polytetrafluoroethylene, and the heat-meltable resin mainly constitutes the node portions and hardly constitutes the fibril portions.

Abstract: Polyurethane/urea elastomers having an isocyanate equivalent index below 100, preferably from about 15 to about 80; containing an effective amount of polyisocyanate component, and an effective amount of an isocyanate reactive component comprising at least one polyamine and at least one polyol, wherein said elastomer contains from about 1 to about 199 equivalent percent amine per isocyanate equivalent.

Abstract: A composite material is disclosed which comprises a shaped, expanded body having a closed cellular structure, and a layer of a thermosetting resin directly bonded to a surface of the shaped body, wherein the shaped body is formed of a mixed thermoplastic resin having a xylene-insoluble content of not greater than 1% by weight and containing at least 50% by weight of a polyolefin resin and at least 2% by weight of a polyene polymer having vinyl group-containing side chains.

Abstract: Polyurethane elastomers exhibiting improved green strength while maintaining short demold times are prepared from ultra-low unsaturation polyoxypropylene polyols containing up to 20 weight percent internal random oxyethylene moieties. The elastomers adsorb less than 10 weight percent water at 0.degree. C. The internal polyoxyethylene moiety-containing polyoxypropylene polyols may be used to prepare ultra-low unsaturation polyoxyethylene capped polyols which are haze-free and which may be used to prepare haze-free 4,4'-MDI prepolymers. Multidisperse blends of monodisperse internal oxyethylene moiety-containing polyoxypropylene polyols of ultra-low unsaturation provide yet further improvements in elastomer processing.

Abstract: Expandable rubber-modified styrene resin beads, expanded rubber-modified styrene resin beads, and expanded molded rubber-modified styrene resin articles are described. The expandable beads comprise a rubber-modified styrene resin comprising a styrene resin having dispersed therein 8 to 15% by weight of conjugated diene rubber particles having a 1,4-cis structure in a proportion of not less than 70% and an average particle size of 1.5 to 3.0 .mu.m, the rubber-modified styrene resin having a mineral oil content of not more than 3.0% by weight, and the expandable rubber-modified styrene resin beads containing 1 to 15% by weight of a volatile blowing agent. The expanded molded article has excellent appearance, impact resistance and softness.

Abstract: In this invention a new form of polytetrafluoroethylene has been found to be compression moldable to provide strong molded articles. It is also useful as an additive or strength binder. The new form is a compression molding powder comprised of comminuted, sheared particles of expanded porous polytetrafluoroethylene, said particles having a modular-microfibrillar structure of irregular shape, and a mean particle size between 5 and 500 micrometers, and having a coating of a thermoplastic fluoropolymer on at least a portion of the particle. By irregular shape is meant that the nodes and fibrils do not have an ordered arrangement. The bulk density is about 0.06 to 0.2 g/cc.

Abstract: In this invention a new form of polytetrafluoroethylene has been found to be compression moldable to provide exceptionally strong molded articles. It is also useful as an additive or strength binder. The new form is a compression molding powder comprised of comminuted, sheared particles of expanded porous polytetrafluoroethylene, said particles having a nudular-microfibrilar structure of irregular shape, and a mean particle size between 5 and 500 micrometers. By irregular shape is meant that the nodes and fibrils do not have an ordered arrangement. The bulk density is about 0.06 to 0.2 g/cc.

Abstract: A foamed isocyanate-based polymer having a cellular structure and comprising a non-surface cross-linked superabsorbent polymer, the foamed polymer being capable of: (i) absorbing at least about 10 times its weight of a 0.9 wt./wt. % aqueous NaCl solution maintained at a temperature of from about 20.degree. to about 25.degree. C., and (ii) retaining at least about 10 times its weight of absorbed aqueous NaCl solution which is bound to the superabsorbent polymer. A process for producing the foamed isocyanate-based polymer is also described. The process comprises the steps of: contacting an isocyanate, an active hydrogen-containing compound, an aqueous blowing agent, a catalyst and a non-surface cross-linked superabsorbent polymer, the superabsorbent polymer being capable of absorbing at least about 10 times its weight of a 0.9 wt./wt. % aqueous NaCl solution maintained at a temperature in the range of from about 20.degree. to about 25.degree. C.

Abstract: A process for the preparation of bead-form expandable styrene polymers by polymerizing styrene, if desired in the presence of further comonomers, in aqueous suspension in the presence of organic molecular colloids as suspension stabilizers and conventional styrene-soluble polymerization catalysts and with addition of a blowing agent and, if desired, conventional additives in effective amounts, wherein the aqueous suspension contains at least one olefinically unsaturated carboxylic acid or a water-soluble salt thereof in an amount, based on the organic phase, of from 0.002 to 0.3% by weight of carboxylate anions.

Abstract: A continuous process for making moldable foam beads comprising a non-crosslinked or crosslinked thermoplastic polymer foam are produced by mixing a composition comprising a non-crosslinkable or crosslinkable thermoplastic polymer or a thermoplastic polymer with a crosslinking agent, additives to achieve specific properties, a blowing agent, extruding the admixture under pressure, crosslinking, when applicable, the admixture under pressure, modulating the admixtures temperature to achieve the desired foaming properties, and then expanding the admixture in a zone of lower pressure to form a foam bead that can be molded.

Abstract: The invention relates to a process for the preparation of bead shaped, expandable polystyrene by the polymerization of styrene in an aqueous suspension in the presence of dimeric .alpha.-methylstyrene as a regulator and a C.sub.3 to C.sub.6 hydrocarbon as a blowing agent, whereby one first reports the content of saturated hydrocarbons, having a boiling point between 70.degree. and 170.degree. C., in the styrene and dimeric .alpha.-methylstyrene, and then enough saturated hydrocarbons, having a boiling point from 70.degree. to 170.degree. C., are added before, during or after the polymerization so that their total content in the suspension is from 0.1 to 0.8 weight percent, based on the styrene.

Abstract: A method and apparatus for producing a lightly crosslinked polyolefin foam and articles made therefrom is disclosed. According to the method, a polyolefin resin is lightly crosslinked, mixed with a blowing agent, forwarded as a molten gel admixture through an extruder, cooled, and expelled from a die into a zone of lower pressure, e.g., the atmosphere or a controlled pressure zone, to produce a uniform fine celled expanded shape.

Abstract: A foamed article of styrene type resin, in which base resin particles are styrene type resin particles obtainable by a graft polymerization of a cis-rich polybutadiene with a styrene type monomer, a blowing agent contains n-pentane as its main component and the foamed article shows a density of 0.015-0.040 g/cm.sup.3, an average foam diameter of 60-300 micrometers and a closed cell foam rate of not less than 50%.

Abstract: An expandable styrene polymer comprisinga) from 0 to 90% by weight of a styrene polymer or styrene copolymer other than b) contains at least 50% by weight of copolymerized styrene,b) from 10 to 100% by weight of a styrene/methacrylamide copolymer comprising from 0.5 to 50% by weight of at least one copolymerized N-substituted methacrylamide of the formula I ##STR1## where R.sup.1 and R.sup.2 are identical or different and are hydrogen, C.sub.1 - to C.sub.15 -alkyl, C.sub.6 - to C.sub.16 -cycloalkyl or C.sub.6 - to C.sub.20 -aryl, it being possible, if R.sup.1 and R.sup.2 contain at least 2 carbon atoms, for at least 2 carbon atoms to be linked via hetero atoms, andc) from 1 to 15% by weight, based on the sum of a) and b), of an aliphatic C.sub.3 - to C.sub.9 -hydrocarbon and/or carbon dioxide as blowing agent.

Abstract: The invention relates to expandable styrene polymers for elastic polystyrene foams, comprisinga) from 50 to 90% by weight of polystyrene and/or a styrene copolymer containing at least 50% by weight of copolymerized styrene,b) from 5 to 30% by weight of at least one styrene-soluble elastomer,c) from 5 to 20% by weight of at least one block copolymer containing styrene as one component,d) from 1 to 15% by weight, based on the sum of a), b) and c), of a low-boiling blowing agent, and, if desired,e) conventional additives in effective amounts,where, in the unfoamed polystyrene beads, component b) is in the form of cell particles and component c) is in the form of particles having a mean size of from 0.2 to 2 .mu.m in the polystyrene phase, and to foams and foam moldings produced therefrom.

Abstract: The invention relates to expandable styrene polymers for elastic polystyrene foams, comprisinga) from 75 to 98% by weight of polystyrene and/or a styrene copolymer containing at least 50% by weight of copolymerized styrene,b) from 2 to 25% by weight of at least one styrene-soluble elastomer,c) from 1 to 15% by weight, based on the sum of a) and b), of a low-boiling blowing agent, and, if desired,d) conventional additives in effective amounts,where the unfoamed beads have a structure in which the elastomer phase is dispersed in the polystyrene phase in the form of cell particles, and to foams and foam moldings produced therefrom.

Abstract: A process for producing expandable particles of a melt compounded blend of polyphenylene ether resin and polyolefin resin. A melt compounded blend of polyphenylene ether resin and polyolefin resin, a blowing agent and water are mixed in a pressure vessel to form a dispersion; the dispersion is heated in the sealed pressure vessel to impregnate the blowing agent in the melt compounded blend of resin particles; the dispersion is then cooled in the sealed pressure vessel; and a cooled blowing agent-impregnated, melt compounded blend of resin particles is removed from the reactor. A preferred blowing agent is Freon.RTM. 11. The particles are pre-expanded by heating, and the pre-expanded particles can be foamed in a conventional mold when heat is applied thereto. A resin molding composition comprising a melt compounded blend of heat-pre-expanded, low density, resilient polyphenylene ether resin and polyolefin resin particles having about 95.0 weight percent to about 5.

Abstract: Expandable thermoplastic polymers in particle form comprising a) at least one organic boron-silicon compound, b) at least one thermoplastic polymer and c) a blowing agent, a process for their preparation, and the foams produced using these expandable thermoplastic polymers.

Abstract: The invention relates to expandable styrene polymers for elastic polystyrene foams, comprisinga) from 50 to 75% by weight of polystyrene and/or a styrene copolymer containing at least 50% by weight of copolymerized styrene,b) from 5 to 30% by weight of a styrene-soluble elastomer,c) from 5 to 20% by weight of at least one block copolymer containing styrene as one component,d) from 15 to 50% by weight of at least one polyolefin,e) from 1 to 15% by weight, based on the sum of a) and b), of a low-boiling blowing agent, and, if desired,f) conventional additives in effective amounts,and to foams produced therefrom.

Abstract: A curable, sprayable composition suitable for reinforcing thin rigid plates or sheets such as are used in the assembly of automobiles is provided. The composition comprises a thermosetting resin, expandable microspheres and a particulate reinforcing material selected from the group consisting of milled glass fibers, milled carbon fibers and mixtures thereof.

Abstract: A polymer blend composition comprising:(a) from 0.5 to 99 percent by weight, based on the total weight of (a), (b), and (c), of an aliphatic .alpha.-olefin homopolymer or interpolymer, or an interpolymer of an .alpha.-olefin and a non-aromatic monomer interpolymerizable therewith;(b) from 0.5 to 99 percent by weight, based on the total weight of (a), (b), and (c), of a homopolymer or interpolymer of monovinylidene aromatic monomers, or an interpolymer of monovinylidene aromatic monomer and a monomer interpolymerizable therewith other than an aliphatic .alpha.-olefin; and(c) from 0.5 to 99 percent by weight, based on the total weight of (a), (b), and (c), of a substantially random interpolymer comprising an .alpha.-olefin and a vinylidene aromatic monomer.

Abstract: The present invention relates to uncrosslinked polyethylene particles for the production of expanded particles that can easily and securely produce expanded particles which can be molded without applying a special internal pressure, are excellent in moldability, such as secondary expansion, fusion and dimensional accuracy, and have a high expansion rate and to uncrosslinked polyethylene expanded particles made of said uncrosslinked polyethylene particles. The present uncrosslinked polyethylene particles for the production of expanded particles are resin particles whose base resin is an uncrosslinked polyethylene having a density of over 0.920 g/cm.sup.3 and up to and including 0.940 g/cm.sup.3 and wherein, in the DSC curve that is obtained by using a differential scanning calorimeter in such a manner that after 1 to 10 mg of the resin particles is heated to 200.degree. C. at 10.degree. C./min and then is cooled to room temperature at 10.degree. C./min, heating is again carried out to 200.degree. C. at 10.

Abstract: A method for making a cellular rubber is described, in which water is added to a high water absorption resin, followed by allowing the resulting mixture to stand and form a hydrous gel. The hydrous gel, with or without a foaming agent, is added to a rubber compound and subjected to foaming under conditions sufficient for vulcanization thereby obtaining a cellular rubber having a closed cell structure. Cosmetic puffs using the cellular rubber are also described.

Abstract: The present invention provides improved compositions of expanded polytetrafluoroethylene (PTFE) and similar polymers and methods for forming and using such compositions. In its preferred embodiment, the present invention employs a mixture of PTFE and expandable thermoplastic microspheres. Through application of an energy source to the mixture, a coherent three dimensional expansion of PTFE can be achieved. The expanded mixture has many of the same beneficial properties of mechanically expanded PTFE and numerous properties previously unavailable with expanded PTFE products.

Abstract: A process for producing expandable particles of a melt compounded blend of polyphenylene ether resin and polyolefin resin. A melt compounded blend of polyphenylene ether resin and polyolefin resin, a blowing agent and water are mixed in a pressure vessel to form a dispersion; the dispersion is heated in the sealed pressure vessel to impregnate the blowing agent in the melt compounded blend of resin particles; the dispersion is then cooled in the sealed pressure vessel; and a cooled blowing agent-impregnated, melt compounded blend of resin particles is removed from the reactor. A preferred blowing agent is Freon.RTM. 11. The particles are pre-expanded by heating, and the pre-expanded particles can be foamed in a conventional mold when heat is applied thereto. A resin molding composition comprising a melt compounded blend of heat-pre-expanded, low density, resilient polyphenylene ether resin and polyolefin resin particles having about 95.0 weight percent to about 5.

Abstract: Disclosed is a cross-linked ethylenic polymer foam structure of an ethylenic polymer material of a cross-linked, substantially linear ethylenic polymer. The substantially linear ethylenic polymer having in an uncross-linked state has: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n <(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylenic polymer having about the same I.sub.2 and M.sub.w /M.sub.n. Further disclosed is a process for making the above foam structure.

Abstract: Foamed polyolefin particles are prepared by dispersion foaming of components consisting essentially of polyolefin particles, a liquid dispersing agent and optionally a volatile blowing agent in a reaction system consisting essentially of a reactor equipped with a stirrer containing said components and a discharge jet, comprising the step of:gassing the components of the reactor by injecting an inert gas into the dispersion below the surface of the liquid in the reactor;and simultaneouslydischarging a three phase mixture of liquid dispersing agent, polymer particles and gas through said jet.

Abstract: A foamed elastomeric polymer with a camouflage appearance on its surface and throughout its mass, characterized by distinct, randomly sized regions of various colors, having curved, nonangular borders with substantially no blend of colors, and being free from gas pockets and blisters. A process for manufacturing a foamed elastomeric polymer of the above description.

Abstract: Disclosed herein is a method of producing foamed particles of a polyolefin resin, which are prevented from fusion-bonding among the particles upon their production, and exhibit excellent moldability without impeding fusion bonding property among the foamed particles upon their molding. The method includes dispersing the particles of the polyolefin resin along with a finely particulate silicate mineral as a dispersing agent and at least carbon dioxide as a foaming agent in a dispersion medium in a closed vessel, heating the dispersion to impregnate the resin particles with the foaming agent, and then releasing the resin particles and dispersion medium into an atmosphere of a pressure lower than the internal pressure of the vessel, thereby expanding the resin particles.

Abstract: Porous, polymer particles comprising a functionalized cross-linked copolymer having microporous regions and macroporous regions in the polymer matrix thereof, wherein the functional groups are essentially present only within the macroporous regions, as well as processes for preparing these particles based on a template polymerization technique followed by removal of the template polymer from the particles are disclosed. The particles of the invention are useful in chromatography, and in various analytical, diagnostic techniques and solid state peptide, DNA synthesis.

Abstract: Disclosed is composite hollow particles which are excellent in solvent resistance and mechanical stability and have strong walls and which can be easily synthesized. The composite hollow particles are prepared by uniformly dispersing the following ingredients in an aqueous medium;(a) an ethylenically unsaturated monomer having at least two radical polymerizable double bonds in one molecule,(b) another polymerizable monomer which is different from the monomer (a),(c) organic particles having an average particle size of 0.01 to 5 micrometer,(d) a initiator, and(e) a dispersant,and then dispersion-polymerizing.

Abstract: A foamed elastomeric polymer with a camouflage appearance on its surface and throughout its mass, characterized by distinct, randomly sized regions of various colors, having curved, non-angular borders with substantially no blend of colors, and being free from gas pockets and blisters. A process for manufacturing a foamed elastomeric polymer of the above description.

Abstract: Expandable styrene polymers containinga) from 80 to 99% by weight of polystyrene,b) from 1 to 20% by weight of a styrene-soluble polymer having a softening point above 140.degree. C.,c) from 3 to 10% by weight, based on the sum of a) and b), of a C.sub.3 - to C.sub.6 -hydrocarbon as blowing agent, and, if desired, d) conventional additives,the mixture of components a) and b) having a melt flow index MFI 200/5 of from 15 to 30, have high heat distortion resistance and a high capacity for expansion.

Abstract: A method for improving the expandability of styrenic polymer particles is disclosed. The method comprises copolymerizing a styrenic monomer with an amount of an acrylate monomer effective to improve the expandability of the particles without adversely affecting their heat sensitivity. Polymer foams of low density can be prepared with reduced amounts of blowing agents.

Abstract: Foamable photodegradable suspension polymers of vinyl aromatic monomers may be prepared by dissolving a copolymer of a vinyl aromatic monomer and a vinyl ketone in the vinyl aromatic monomer and suspension polymerizing the resulting mixture. The resulting polymer may be foamed and used in the manufacture of food containers.

Abstract: In foams having a density of from 0.01 to 0.2 g/cm.sup.3 and a cell count of from 2 to 1,000 cells/mm.sup.2 and based on an impact copolymer, the impact copolymer consists ofa) from 1 to 55% by weight of a block copolymer ofa.sub.1) from 35 to 65% by weight of ethylene anda.sub.2) from 35 to 65% by weight of propylene andb) from 45 to 99% by weight of a random copolymer ofb.sub.1) from 0.5 to 6% by weight of ethylene and from 94 to 99.5% by weight of propylene, or ofb.sub.2) from 0.5 to 12% by weight of but-1-ene and 88 to 99.5% by weight of propylene.

Abstract: Substantially homogeneous aqueous suspensions of low density microspheres are presented as contrast media for imaging the gastrointestinal tract and other body cavities using computed tomography. In one embodiment, the low density microspheres are gas-filled. With computed tomography, the contrast media serve to change the relative density of certain areas within the gastrointestinal tract and other body cavities, and improve the overall diagnostic efficacy of this imaging method.

Abstract: Expandable styrene polymers which contain from 10 to 90% by weight of a crosslinked styrene-diene copolymer containing from 2 to 45% by weight of the diene, and from 1 to 10% by weight of a C.sub.3 -to C.sub.6 -hydrocarbon as blowing agent can be processed to give foams which have high resistance to aromatics.

Abstract: Elastomeric low density foamable compositions are described which are prepared from blends comprised of a major amount of a block copolymer comprised of an alkenyl aromatic and a conjugated diene and a minor amount of one or more other thermoplastic resins. Also described are such foamable compositions wherein such blends are comprised of a major amount of a triblock copolymer of the A-B-A type and a minor amount of polystyrene resin and/or polyphenylene ether resin. Also described are processes for preparing such low density foamable compositions and articles made therefrom.

Abstract: Foamable photodegradable suspension polymers of vinyl aromatic monomers may be prepared by dissolving a copolymer of a vinyl aromatic monomer and a vinyl ketone in the vinyl aromatic monomer and suspension polymerizing the resulting mixture. The resulting polymer may be foamed and used in the manufacture of food containers.

Abstract: Microsphere wet cake is mixed with a surface barrier coating effective to prevent agglomeration and surface bonding of the microspheres, and removing water by drying with continuous mixing at high shear. In a subsequent step, by the control of the application of heat and balancing temperature and low shear mixing, it is possible to also control expansion of the microspheres.The surface barrier coating in the present invention is any one of a wide diversity of materials which meet the requirements of the intended function, i.e., to prevent the agglomeration of the microspheres during the process. Suitable materials include, by way of example, dry inorganic pigments or filler materials, and the like, and related organic materials.

Abstract: An oil-resistant, expandable styrene polymer containsa) from 10 to 90% by weight of uncrosslinked polystyrene and/or an uncrosslinked styrene copolymer containing at least 50% by weight of copolymerized styrene,b) from 10 to 90% by weight of a crosslinked styrene polymer which contains at least 0.1% by weight, but less than 2% by weight, of a copolymerized monomer having at least two olefinic double bonds,c) from 1 to 10% by weight, based on the sum of a) and b), of a C.sub.3 - to C.sub.6 -hydrocarbon as blowing agent, and, if desired,d) conventional additives in effective amounts,the mixture of a) and b) having a melt flow index MFI (200.degree. C., 5.0 kp) in accordance with DIN 53 735 of from 1 to 20 [g/10 min].

Abstract: Expandable styrene polymers containinga) from 80 to 99% by weight of polystyrene,b) from 1 to 20% by weight of a styrene-soluble polymer having a softening point above 140.degree. C.,c) from 3 to 10% by weight, based on the sum of a) and b), of a C.sub.3 - to C.sub.6 -hyrocarbon as blowing agent, and, if desired, d) conventional additives,the mixture of components a) and b) having a melt flow index MFI 200/5 of from 15 to 30, have high heat distortion resistance and a high capacity for expansion.

Abstract: A stabilized powdered endothermic blowing agent .[.which.]. is a mixture or a polycarboxylic acid and an inorganic carbonate, .[.and.]. .Iadd.the .Iaddend.polycarboxylic acid and inorganic carbonate each having been surface treated with a component which prevents water from being absorbed thereby. The blowing agent is incorporated into a polymeric concentrate used for producing foamed products.