Abstract: Styrene polymer foam particles of from 10 to 30 kg/m.sup.3 in density are obtained by foaming styrene polymers which, per kg, contain from 0.7 to 3 moles of blowing agent mixture composed of from 60 to 90 mol % of water and from 10 to 40 mol % of the C.sub.4 - or C.sub.5 -hydrocarbon with the aid of microwaves.

Abstract: A pre-expanded particle of a non-crosslinked linear low density polyethylene having an average cell diameter as large as 120 to 1,200 .mu.m which can be molded, without further imparting an expandability prior to molding or without aging under pressure, by heating in a closed mold permeable to a fluid heating medium such as steam to form a well bonded unitary cellular molded article having a good appearance, a high expansion ratio and improved heat resistance and mechanical property with a slight volumetric shrinkage.

Abstract: Pre-formed particles of an uncrosslinked, linear low-density polyethylene have a crystalline structure characterized in that two endothermic peaks appear on a DSC curve obtained by differential scanning calorimetry of the pre-foamed particles (said DSC curve having been obtained by heating 1-5 mg of the pre-foamed particles to 220.degree. C. at a rate of 10.degree. C./min by a differential scanning calorimeter) and the energy at the endothermic peak on the higher-temperature side is 5 J/g or more. A process for the production of the pre-foamed particles of the uncrosslinked, linear low-density polyethylene is also disclosed.

Abstract: A process for post-treating pre-expanded polyolefin resin particles which comprises charging in a vessel pre-expanded polyolefin resin particles which are pre-expanded by using an inflammable blowing agent, supplying an inert gas into the vessel, and then discharging the inert gas with the inflammable blowing agent gas extracted from the pre-expanded polyolefin resin particles, from the vessel. According to the process of the invention, the inflammable blowing agent can be extracted efficiently, safely and in a short time from the pre-expanded polyolefin resin particles which are pre-expanded by using the inflammable blowing agent. Consequently, the spontaneous cambustion of the particles can be completely avoided even if sparks are generated on the surface of the pre-expanded particles, therefore, it becomes easy to handle the pre-expanded polyolefin resin particles because the particles can be dried and transported by a pneumatic conveyer.

Abstract: The present invention provides polypropylene resin pre-expanded beads formed by shrinking polypropylene resin pre-expanded beads originally having a bulk density of not higher than 0.0930 g/cc to give then a bulk volume ratio of 10-75% at the normal temperature and the normal pressure, a manufacturing method thereof and an expansion-molding method with the aforementioned pre-expanded beads. According to this invention, it is possible to greatly reduce storing and transporting costs per unit weight of pre-expanded beads.

Abstract: Expandable polymers in particle form for the preparation of foams having high heat distortion resistance contain from 20 to 94.9% by weight of a styrene polymer, from 0.1 to 75% by weight of a polyphenylene ether and from 5 to 20% by weight of a blowing agent mixture of aliphatic or cycloaliphatic hydrocarbons on the one hand and aromatic hydrocarbons, alcohols, ketones, ethers, esters and/or chlorohydrocarbons on the other hand.

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: Enhanced hiding power for opacifiers in paints, inks, and other coatings is provided by employing the opacifiers, such as TiO.sub.2, ZnO, talc, CaCo.sub.3, and the like, adhered to or embedded in the surface of thermoplastic microspheres. The composite opacifier-microsphere material is readily formed with a preselected specific gravity, so that there is little tendency for the material to separate. In addition, the composite behaves in the coating as a opacifier-air interface, having a very high difference in refractive indices, and exceptional hiding power. The high volume to weight ratio of the composite affords very attractive economic advantages, effectively reducing the weight proportion of opacifiers required in the formulations, and other related advantages.

Abstract: Enhanced hiding power for opacifiers in paints, inks, and other coatings is provided by employing the opacifiers, such as TiO.sub.2, ZnO, talc, CaCo.sub.3, and the like, adhered to or embedded in the surface of thermoplastic microspheres. The composite opacifier-microsphere material is readily formed with a preselected specific gravity, so that there is little tendency for the material to separate. In addition, the composite behaves in the coating as a opacifier-air interface, having a very high difference in refractive indices, and exceptional hiding power. The high volume to weight ratio of the composite affords very attractive economic advantages, effectively reducing the weight proportion of opacifiers required in the formulations, and other related advantages.

Abstract: Syntactic foam graphic arts print media are provided which are particularly suitable for application to a substrate using high speed mechanical printing processes. The invention involves adding to a basic print medium a minor amount of pre-expanded, nonfriable, thermoplastic polyvinylidene chloride based microspheres substantially heat stable between about -20.degree. C. and 175.degree. C., having a particle size to about 10 to 100 microns in diameter, to produce syntactic foams having unlimited shelflife stability. The print media thereby produced may be applied to any known substrate in any desired graphic pattern.

Abstract: Enhanced hiding power for opacifiers in paints, inks, and other coatings is provided by employing the opacifiers, such as TiO.sub.2, ZnO, talc, CaCO.sub.3, and the like, adhered to or embedded in the surface of thermoplastic microspheres. The composite opacifier-microsphere material is readily formed with a preselected specific gravity, so that there is little tendency for the material to separate. In addition, the composite behaves in the coating as a opacifier-air interface, having a very high different in refractive indices, and exceptional hiding power. The high volume to weight ratio of the composite affords very attractive economic advantages, effectively reducing the weight proportion of opacifiers required in the formulations, and other related advantages.

Abstract: Enhanced hiding power for opacifiers in paints, inks, and other coatings is provided by employing the opacifiers, such as TiO.sub.2, ZnO, talc, CaCo.sub.3, and the like, adhered to or embedded in the surface of thermoplastic micorspheres. The composite opacifier-microsphere material is readily formed with a preselected specific gravity, so that there is little tendency for the material to separate. In addition, the composite behaves in the coating as a opacifier-air interface, having a very high difference in refractive indices, and exceptional hiding power. The high volume to weight ratio of the composite affords very attractive economic advantages, effectively reducing the weight proportion of opacifiers required in the formulations, and other related advantages.

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 process of forming hollow microspheres containing carbon or a polymer which is a carbon precursor. The process comprises forming a solution in a liquid solvent of a polymer having the following properties (a) a molecular weight of at least 10,000 and a long chain structure; (b) an ability to be coagulated by or precipitated from the solution by a non-solvent for the polymer; (c) an ability to form a continuous stretchable film when coagulated or precipitated from solution; (d) a chemical structure which is infusible or capable of being rendered infusible, and (e) a high carbon yield of at least 30% by weight upon being carbonized in a non-reactive atmosphere. An insoluble particulate blowing agent is incorporated into the solution and the solution is then divided into droplets and the droplets are introduced into a liquid bath containing a suitable non-solvent for the polymer.

Abstract: A process for producing pre-expanded particles of a thermoplastic resin, wherein said particles are polyolefin resin particles which are obtained by polymerizing an olefin in the presence of a Ziegler-Natta catalyst, said polyolefin resin particles containing no more than 1% by weight of particles having a particle diameter of 105 .mu.m or smaller and having a particle size distribution represented by equation:R(Dp)=100exp[-(Dp/De).sup.n ]wherein Dp represents a particle diameter (.mu.m) of polymer particles; R(Dp) represents a cummulative weight percentage; De represents an absolute size constant that is a particle diameter (.mu.m) corresponding to R(Dp)=36.8% by weight; and n represents a distribution constant, in which De is 300 or more, and n is 2.5 or more. Pre-expanded polyolefin resin particles free from scatters of cell diameter or particle diameter and having a high expansion ratio can be obtained without using pelletized polymer particles or pulverized pellets of polymer particles.

Abstract: Microsphere wet cake is mixed with a processing aid efective to prevent agglomeration and surface bonding of the microspheres, and thereafter removing water by drying with continuous mixing, optionally also under reduced pressure, i.e. vacuum drying. By the control of the application of heat and balancing temperature and the mixing, and optionally also the reduced pressure, it is possible to also control expansion of the microspheres from substantially none to substantially theoretical limits of expansion.The processing aid 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: Prefoamed particles consisting essentially of an ethylene/propylene random copolymer, wherein said prefoamed particles are obtained by foaming particles of an ethylene/propylene random copolymer containing 1 to 4% by weight of random-copolymerized ethylene at a temperature in the range of from Tm - 15.degree. C. to Tm - 5.degree. C. (in which Tm is a temperature at which to terminate melting of the copolymer) and within the range of 141.degree. to 151.degree. C., and wherein said prefoamed particles have a crystal structure characterized in that in a DSC curve obtained by heating 1 to 3 mg of the copolymer prefoamed particles to 220.degree. C. at a heating rate of 10.degree. C./min. with a differential scanning calorimeter, there appear a peak (characteristic peak) characteristic of the copolymer and another peak (high temperature peak) at a higher temperature than a temperature at which the characteristic peak appears.

Abstract: Microsphere wet cake is mixed with a processing aid effective to prevent agglomeration and surface bonding of the microspheres, and thereafter removing water by drying with continuous mixing, optionally also under reduced pressure, i.e. vacuum drying. By the control of the application of heat and balancing temperature and the mixing, and optionally also the reduced pressure, it is possible to also control expansion of the microspheres from substantially none to substantially theoretical limits of expansion.The processing aid 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: A process for producing expanded particles of a styrene-acrylonitrile-butadiene copolymer is disclosed, comprising dispersing styrene-acrylonitride-butadiene copolymer particles in water in a closed vessel, feeding a volatile blowing agent to the aqueous dispersion in the closed vessel, heating the aqueous dispersion to a temperature higher than a glass transition point of the copolymer particles by at least 20.degree. C. to impregnate the volatile blowing agent into the copolymer particles, and opening one end of the closed vessel to release the aqueous dispersion containing the expandable copolymer particles into a low pressure zone having a pressure lower than the inner pressure of the closed vessel. The resulting expanded particles have a degree of expansion of from 10 to 50.

Abstract: Expandable and expanded plastic materials having a majority of alkyl acrylate monomeric repeat units are disclosed. These materials when expanded have a volume expansion of at least 60 and maintain that volume expansion for a period of at least 30 minutes under expansion conditions after reaching the volume expansion of 60. Expandable and expanded plastic materials having a majority of alkyl acrylate monomeric repeat units and an inhibitor for the monomer(s) and a crosslinker incorporated into the plastic material upon monomer polymerization are also disclosed. Also disclosed are expandable and expanded plastic materials having a majority of alkyl acrylate monomeric repeat units with blowing agents of 2,2-dimethylbutane, 2,3-dimethylbutane or mixtures of one or both with 1-chloro-1,1-difluoroethane or mixtures of at least 30 percent of one or both with other volatile blowing agents.

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 or expandable particles which are 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: Pellets of a chlorinated vinyl chloride resin composition comprising inorganic materials, a solvent and a blowing agent; a pre-expanded particle of a chlorinated vinyl chloride resin comprising inorganic materials and a solvent and a process for preparing the pre-expanded particle of the chlorinated vinyl chloride resin containing inorganic materials which comprises kneading a chlorinated vinyl chloride resin, inorganic materials and a solvent, pelletizing the kneaded mixture impregnating a physical blowing agent into the resulting pellets and pre-expanding the pellets. The present invention makes it possible to be contained a large amount of inorganic materials in a chlorinated vinyl chloride resin by forming a uniform gel phase of the chlorinated vinyl chloride resin and the solvent and wrapping inorganic materials in the gel phase. A foamed article produced by employing pre-expanded particles of the chlorinated vinyl chloride resin containing inorganic materials has an excellent heat resistance, i.e.

Abstract: A process for forming hollow microspheres containing carbon or a polymer which is a carbon precursor. The process comprises forming a solution in a liquid solvent of a polymer having the following properties (a) a molecular weight of at least 10,000 and a long chain structure; (b) an ability to be coagulated by or precipitated from the solution by a non-solvent for the polymer; (c) an ability to form a continuous stretchable film when coagulated or precipitated from solution; (d) a chemical structure which is infusible or capable of being rendered infusible, and (e) a high carbon yield of at least 30% by weight upon being carbonized in a non-reactive atmosphere. An insoluble particulate blowing agent is incorporated into the solution and the solution is then divided into droplets and the droplets are introduced into a liquid bath containing a suitable non-solvent for the polymer.

Abstract: A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing the dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40.degree. C. According to the process of the present invention, there can be obtained pre-expanded thermoplastic resin particles with a large average diameter of cells. By molding the pre-expanded particles obtained by the present invention, molded articles which are small in dimensional shrinkage and excellent in surface appearance can be obtained without imparting expandability to the particles or aging the particles under pressure prior to molding.

Abstract: An expansion-molded article of a polypropylene resin is produced by filling pre-foamed particles of the polypropylene resin, which have a crystalline structure featuring an inherent peak inherent to the polypropylene resin and a high-temperature peak on the temperature side higher than the temperature corresponding to the inherent peak on a DSC curve obtained by differential scanning calorimetry of the pre-foamed particles and a bulk density of 0.04 g/cm.sup.3 or higher and require melting energy of 8-12 J/g at the high-temperature peak, in a mold without applying any pretreatment to the pre-foamed particles to build up an internal pressure therein, and then heating the pre-foamed particles, whereby the pre-foamed particles are caused to expand into the expansion-molded article conforming with the mold. The pre-foamed particles may alternatively have a bulk density lower than 0.04 g/cm.sup.3 and require melting energy of at least 8 J/g.

Abstract: Particulate styrene polymers containing blowing agents are prepared by a process in which an aliphatic hydrocarbon of 7 to 9 carbon atoms is added in an amount of from 0.01 to 0.5% by weight, based on the styrene polymer, before, during or after the polymerization. The particulate styrene polymers can be processed to foam blocks and moldings having a satisfactory smooth surface.

Abstract: Improved reexpandable shrunken foam bodies of styrene-acrylonitrile type resin possessing an ability to reexpand to the original volume of the highly foamed state when left standing at room temperature under atmospheric pressure and a method for the manufacture of such reexpandable shrunken foam bodies.The aforementioned shrunken foam bodies are obtained by causing a styrene-acrylonitrile type resin to contain a prescribed large amount of a specific foaming agent exhibiting a slow gas permeation speed to the base resin and possessing the boiling point exceeding a fixed lower limit, heating the resin with steam thereby setting it to foam highly, and releasing the foamed resin into the atmosphere to be cooled and shrunk therein.The aforementioned shrunken foam bodies are convenient for the purpose of transportation and storage. They are useful as fillers intended to absorb shocks and insulate heat.

Abstract: Pellets of a chlorinated vinyl chloride resin composition comprising inorganic materials, a solvent and a blowing agent; a pre-expanded particle of a chlorinated vinyl chloride resin comprising inorganic materials and a solvent and a process for preparing the pre-expanded particle of the chlorinated vinyl chloride resin containing inorganic materials which comprises kneading a chlorinated vinyl chloride resin, inorganic materials and a solvent, pelletizing the kneaded mixture, impregnating a physical blowing agent into the resulting pellets and pre-expanding the pellets. The present invention makes it possible to be contained a large amount of inorganic materials in a chlorinated vinyl chloride resin by forming a uniform gel phase of the chlorinated vinyl chloride resin and the solvent and wrapping inorganic materials in the gel phase. A foamed article produced by employing pre-expanded particles of the chlorinated vinyl chloride resin containing inorganic materials has an excellent heat resistance, i.e.

Abstract: Pellets of a chlorinated vinyl chloride resin composition comprising inorganic materials, a solvent and a blowing agent; a pre-expanded particle of a chlorinated vinyl chloride resin comprising inorganic materials and a solvent and a process for preparing the pre-expanded particle of the chlorinated vinyl chloride resin containing inorganic materials which comprises kneading a chlorinated vinyl chloride resin, inorganic materials and a solvent, pelletizing the kneaded mixture, impregnating a physical blowing agent into the resulting pellets and pre-expanding the pellets. The present invention makes it possible to be contained a large amount of inorganic materials in a chlorinated vinyl chloride resin by forming a uniform gel phase of the chlorinated vinyl chloride resin and the solvent and wrapping inorganic materials in the gel phase. A foamed article produced by employing pre-expanded particles of the chlorinated vinyl chloride resin containing inorganic materials has an excellent heat resistance, i.e.

Abstract: Foamed particles of propylene-type polymer of substantially non-crosslinked type, wherein the propylene-type polymer particles have a Melt Index of from 0.1 to 20, said polymer is at least one member selected from the group consisting of:(a) a soft polypropylene homopolymer having an <mmmm> partial rate of a stereoregular pentad partial rate by .sup.13 C-NMR Spectrum of from 45 to 85% and a fusion heat quantity of from 5 to 22 cal/g; and(b) a random copolymer of propylene and an .alpha.-olefin having a carbon number of 4 or more, or a random copolymer of propylene, an .alpha.-olefin having a carbon number of 4 or more, and ethylene, in which the content of the .alpha.-olefin having a carbon number of 4 or more is from 7 to 30 mol %, the content of ethylene is 5 mol % or less, and the cold xylene-soluble matter of said copolymer is from 15 to 60 wt %, said polymer particles being foamed with the use of an evaporation type blowing agent.

Abstract: Polystyrene beads or beads of other thermoplastic material are expanded to a consolidated foam structure in a hollow cavity of a marine float or other structure by providing the beads with a uniform coating of a saturated brine solution or other aqueous solution of water-soluble salt and exposing the solution to microwave energy to boil the solutioln and thereby heat the beads to cause expansion and fusion to a foam structure.

Abstract: A pre-expanded particle of a propylene resin having two melting temperatures as determined by DSC, the heat of fusion for the peak based on the higher melting temperature being 0.5 to 2.3 cal/g. By using the pre-expanded particles of the propylene resin of the invention, foamed articles having excellent surface appearance, small dimentional shrinkage can be easily obtained without the procedure for giving the internal pressure.

Abstract: Porous particles of vinyl resin are disclosed where said particles are non-spherical in shape, highly porous, skinless and friable. Processes are also disclosed for producing these novel particles. The particles are preferably PVC and exhibit an ability to absorb large amounts of plasticizer in a short time.

Abstract: Pre-foamed particles are produced by dispersing resin particles, which contain nucleocells, in a dispersing medium in a closed vessel, heating the contents to a temperature of the softening point of the particles or higher and holding the contents at the temperature for a predetermined period of time while pressurizing the contents with an inorganic gas, and then opening the vessel at one end thereof so as to release the particles and medium into an atmosphere of a pressure lower than the internal pressure of the vessel, thereby causing the resin particles to foam. The above production process provides good pre-foamed particles with ease and without failure. It is also possible to avoid deleterious effects due to the swelling action of foaming agents.

Abstract: In a process for preparing pre-expanded particles of a thermoplastic resin which comprises releasing into a low pressure zone an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent, the dispersion being maintained at an elevated temperature under pressure in a pressure vessel, the improvement which comprises releasing the dispersion through an orifice having a ratio of the length to the average diameter of 4 to 100. According to the present invention, the pre-expanded particles having cells which are uniform in diameter and have an average dimeter of not less than 200 .mu.m can be obtained, and therefore the articles molded in a mold from the pre-expanded particles are small in the shrinkage and strain, are excellent in the appearance, and are increased in the productivity.

Abstract: Microsphere wet cake is mixed with a processing aid effective to prevent agglomeration and surface bonding of the microspheres, and thereafter removing water by drying with continuous mixing, optionally also under reduced pressure, i.e. vacuum drying. By the control of the application of heat and balancing temperature and the mixing, and optionally also the reduced pressure, it is possible to also control expansion of the microspheres from substantially none to substantially theoretical limits of expansion.The processing aid 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: A pre-expanded particle of a propylene resin having two melting temperatures as determined by DSC, the heat of fusion for the peak based on the higher melting temperature being 0.5 to 2.3 cal/g. By using the pre-expanded particles of the propylene resin of the invention, foamed articles having excellent surface appearance, small dimentional shrinkage can be easily obtained without the procedure for giving the internal pressure.

Abstract: A process is disclosed for the production of expanded particles of polymeric material wherein unexpanded particles of the material are contacted with a nitrogen-containing inorganic gas under a first pressure condition to impregnate the particles with the gas. The gas impregnated particles are heated to a temperature higher than the softening point of the material, and dispersed into a liquid medium. The resulting dispersion is subjected to a lower pressure to expand the particles. The expanded particles may be used as prefoamed particles for the molding of foamed articles.

Abstract: Propylene-base random copolymer particles suitable for use in the production of pre-foamed particles are obtained by heating starting copolymer particles of ethylene-propylene random copolymer to the crystallization temperature thereof and then quenching them in a medium at a temperature of (the crystallization temperature-30.degree. C.) or lower. Pre-foamed particles produced using the copolymer particles contain large cells are columnar in shape with an average diameter D of 1.7 mm or less and an L/D.gtoreq.1. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.

Abstract: A process for producing propylene random copolymer resin foamed particles is disclosed. The process comprises dispersing propylene-ethylene random copolymer resin particles having an ethylene content of from 1 to 12% by weight in water in a closed vessel, feeding an inorganic gas into the closed vessel to raise the pressure within the closed vessel to at least 5 Kg/cm.sup.2 G, heating the dispersion to a temperature above the melting point of said copolymer resin particles but not higher than that by 25.degree. C. or more, opening a discharge port provided in the closed vessel below the water surface, and releasing the copolymer resin particles together with water as a dispersing medium into an atmosphere having a lower pressure than in the closed vessel. A foamed product produced by molding the foamed particles has firm bondage among the particles and excellent mechanical strength.

Abstract: An energy absorber suitable for use as a bumper core or the like is formed of an expansion-molded article of prefoamed particles. The prefoamed particles use, as the base resin thereof, a resin obtained by impregnating high-density polyethylene with an aromatic vinyl monomer and polymerizing the monomer. The absorber has a density (.rho.) of 0.015-0.15 g/cm.sup.3 and satisfies the following relation:E.sub.20 /.rho..gtoreq.45 kg.multidot.cm/gwherein E.sub.20 (kg.multidot.cm/cm.sup.3) means the quantity of energy absorbed upon 70% compression at 20.degree. C. and .rho. has the same meaning as defined above.

Abstract: Pre-foamed particles are formed of a polyethylene resin obtained by crosslinking a linear super-low density polyethylene having a density of 0.880-0.914 g/cm.sup.3 and a melt flow rate of 0.01-10 g/10 minutes. The gel content of the pre-foamed particles is 0.06-45%.

Abstract: A high temperature, flame resistant polyimide foam material and methods of making open and closed cell, rigid and flexible foams from common precursors. An aromatic tetracarboxylic dianhydride is reacted with an amino acid and an alcohol or mixture of alcohols to produce an N-substituted imido acid ester. The product is then reacted with an aromatic diamine. The resulting liquid is dried, ground to a course powder, ad classified into sizes from 0.25 mm to 2 mm by sieving. The powder is suitable for foaming without further modificaiton, by exapansion at 100 to 3000 in a closed mold to form a well consolidated, uniform, mostly closed cell product. When expanded unrestrictedly, open cell flexible or rigid consolidated foams are produced, depending on choice of alcohol(s). The foams have excellent resistance to heat and flame, and bond well to glass prepreg to form rigid structures.

Abstract: The present disclosure is directed to foam particles of a linear, uncrosslinked ethylenic resin which can be expansion molded by heating in its uncrosslinked state. The present disclosure is also concerned with a process for preparing foam particles of a linear uncrosslinked ethylenic resin and a process for the in-mold foam molding of said resin particles.

Abstract: Expandable styrene polymer particles which have anti-static and anti-lumping properties during expansion and after molding into an article are produced by adding 0.1 to 0.4 parts of dialkyl bisalkoxylated quaternary ammonium salts per 100 parts of polymer particles by coating of the expandable polymer particles with the salts. The salts may be added as sole antistatic agent or in addition to the known internal additives which impart fastcool and antilump properties.

Abstract: Substantially non-crosslinked polypropylene resin foamed particles having a bulk density of from 8 to 100 g/l and a particle diameter of from 1 to 5 mm, the polypropylene resin is composed of from 5 to 30% by weight of a room-temperature xylene soluble matter having an ethylene content of from 20 to 80% by weight and from 70 to 95% by weight of a room-temperature xylene insoluble matter having a main melting peak temperature of from 130.degree. to 158.degree. C. The foamed particles provide a foamed product having well-balanced properties, such as low-temperature moldability, heat resistance, recovery from compression, and the like.

Abstract: Expandable styrene polymer particles which have anti-static and anti-lumping properties during expansion and after molding into an article are produced by adding 0.1 to 0.4 parts of trialkyl alkylalkoxylated quaternary ammonium salts, per 100 parts of polymer particles by coating of the expandable polymer particles with the salts. The salts may be added as sole antistatic agent or in addition to the known internal additives which impart fast-cool and anti-lump properties.

Abstract: A pre-expanded particle suitable for foaming in a mold comprising non-crosslinked linear low density polyethylene which has a characteristic property that an inclination of slope line obtained on a graph when logarithmic values of melt tension of the polyolefin are plotted as ordinate and reciprocals of absolute temperature at which the melt tension is measured are plotted as abscissa is not more than 1,500 is provided. A foamed article produced from the pre-expanded particles has an excellent appearance, a flat surface and good mechanical strength, and is useful for wrapping material, insulating material, a container or a fender of cars.

Abstract: Prefoamed crosslinked propylene-type resin particles prepared by using as a base resin a propylene random copolymer whose amount of heat of crystallization determined by a DSC method is 19 to 10 cal/g. The prefoamed particles have a gel fraction of 1 to 65%. Also provided is a molded article of a crosslinked propylene-type resin which is a fused aggregate of the aforesaid prefoamed particles in which the number of cells, N per mm.sup.2, and the density, d (g/cm.sup.3), have the relation represented by the expression 2<N.sup.1/2 /d.sup.1/3 <45.

Abstract: For use in an automobile bumper, a core material composed of a molded article of prefoamed polyolefin resin particles. The core material has a density of 0.05 to 0.15 g/cm.sup.3 and the relation represented by the following expressionE.sub.20/.rho. .gtoreq.20 kg-cm/gwherein E.sub.20 is the amount of energy absorption (kg-cm/cm.sup.3) when the core material is compressed to 50% at 20.degree. C., and .rho. is the density (g/cm.sup.3) of the core material.