Abstract: A foamed, non-crosslinked resin particle having a bulk density of not greater than 0.045 g/cm.sup.3 and an average cell diameter of at least 200 .mu.m. The non-crosslinked resin includes a polypropylene resin to which a vinyl comonomer is graft-polymerized in such an amount that the weight ratio of the polypropylene resin to the grafted polymer of the vinyl comonomer is in the range of 97:3 to 65:35. The foamed resin particles are produced by grafting a vinyl comonomer to polypropylene resin particles at a temperature of less than 90.degree. C. in the presence of a specific radical polymerization initiator to obtain modified polypropylene resin particles and, then, expanding the modified polypropylene resin particles. The initiator used requires a temperature of not higher than 70.degree. C. for obtaining a half life of 10 hours.

Abstract: Disclosed herein is an molded article of foamed and expanded beads of a propylene resin, which is obtained by heating and molding the foamed beads of the propylene resin, wherein the apparent density of the molded article is 0.11 to 0.45 g/cm.sup.3, a value obtained by dividing its maximum bending strength (kgf/cm.sup.2) determined in accordance with JIS K 7221 by the apparent density (g/cm.sup.3) is at least 160 (kgf/cm.sup.2)/(g/cm.sup.3), and the average number of cells at its section is within a range of 5 to 100 cells/mm.sup.2.

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: 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: Disclosed herein is a method of producing foamed particles of an ethylene-based resin, which have a high expansion ratio and are free from the formation of fine cells, by dispersing particles of the uncrosslinked ethylene-based resin, which are obtained using, as a base resin, an ethylene/.alpha.-olefin copolymer containing, as a comonomer component, 1.0-10 wt. % of an .alpha.-olefin having 4-10 carbon atoms, in a dispersion medium in the presence of a foaming agent in a closed vessel, heating the resultant dispersion to impregnate the resin particles with the foaming agent, and then releasing the resin particles into a region of a pressure lower than the internal pressure of the vessel at a foaming temperature not lower than the softening temperature of the resin particles, thereby expanding the resin particles.

Abstract: A filling apparatus for filling foamed particles of a thermoplastic resin into a mold. The apparatus includes a weigh hopper equipped with a weighing means, a foamed particle feeder adapted to control the amount of the foamed particles of the thermoplastic resin to be fed to the weigh hopper according to the weight of the foamed particles contained in the weigh hopper, a particle feed hopper adapted to temporarily keep a fixed weight of the foamed particles, which have been weighed in the weigh hopper, a holding hopper which acts as a pressurized tank, and a filling machine for filling the foamed particles into a mold. The filling apparatus allows for the successive weighing and pressurized containment of the foamed particles prior to being fed into the mold cavities.

Abstract: Prefoamed synthetic resin particles are produced by dispersing foamable resin particles in a dispersing medium within a closed vessel, said foamable resin particles containing a water-soluble inorganic substance and a blowing agent therein, and then releasing the foamable resin particles and the medium into an atmosphere of a pressure lower than that inside the vessel, whereby the thus-released foamable resin particles are allowed to undergo foaming.

Abstract: A process for the production of expanded resin particles is disclosed, wherein an aqueous dispersion containing expandable particles of a polyolefin resin is discharged at a temperature higher than the softening point of the resin from a high pressure condition to a low pressure condition to expand the expandable particles and wherein the expandable particles contain fine particles of an inorganic material coated with an agent selected from isopropyltriisostearic titanate, tetraoctadecyl titanate, acetoalkoxyaluminum diisopropylates, stearic acid, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane and vinyltriethoxysilane.