Expandable methyl methacrylate resin particles capable of providing a foamed molded product which has excellent surface quality and with which a residue hardly remains after burning are provided. The expandable methyl methacrylate resin particles contain a base resin and a blowing agent. The base resin includes, as constitutional units, a specific amount of a methyl methacrylate unit, a specific amount of an acrylic ester unit, and a specific amount of a constitutional unit derived from a crosslinking agent. The expandable methyl methacrylate resin particles have a volume-average particle size of 0.30 mm to 0.50 mm.

The present invention aims to provide a masterbatch for foam molding which can be suitably used in molding involving high shear force or molding requiring low molding temperature and which can provide a foam molded article having a high expansion ratio and good appearance quality. The present invention also aims to provide a foam molded article formed from the masterbatch for foam molding. Provided is a masterbatch for foam molding, containing: a base resin; and a thermally expandable microcapsule, the masterbatch having a true specific gravity of 0.80 g/cm.sup.3 or more and a Mooney viscosity ML 1+4 (100° C.) of 20 to 90, the base resin containing an EPDM resin, the masterbatch containing the thermally expandable microcapsule in an amount of 40 to 300 parts by weight relative to 100 parts by weight of the base resin.

The present invention aims to provide a masterbatch for foam molding which can be suitably used in molding involving high shear force or molding requiring low molding temperature and which can provide a foam molded article having a high expansion ratio and good appearance quality. The present invention also aims to provide a foam molded article formed from the masterbatch for foam molding. Provided is a masterbatch for foam molding, containing: a base resin; and a thermally expandable microcapsule, the masterbatch having a true specific gravity of 0.80 g/cm.sup.3 or more and a Mooney viscosity ML 1+4 (100° C.) of 20 to 90, the base resin containing an EPDM resin, the masterbatch containing the thermally expandable microcapsule in an amount of 40 to 300 parts by weight relative to 100 parts by weight of the base resin.

Polyamide-based resin expanded beads having a crystallite size of more than 8 nm as measured by X-ray diffraction method are provided.

A foamable polypropylene composition, and foamed polypropylene and a preparation method therefor are provided. The polypropylene composition comprises polypropylene, a polypropylene modifier, a foaming agent, and an optional nucleating agent. A preparation method for the polypropylene modifier comprises: enabling polar monomer grafted polypropylene to be in contact with a component A to react and carrying out extruding pelletizing, wherein a polar monomer in the polar monomer grafted polypropylene can chemically react with the component A; the polar monomer is selected from at least one of dimethylamino methacrylate, epoxy acrylate, trimeric acrylic isocyanurate, and acrylamide; and the component A is selected from at least one of polyisocyanate, polyethylene oxide, and an amido-containing substance. The foamed polypropylene has an obtained foaming ratio of 12 times or more, and also has high tensile and flexural properties.

A foamable polypropylene composition, and foamed polypropylene and a preparation method therefor are provided. The polypropylene composition comprises polypropylene, a polypropylene modifier, a foaming agent, and an optional nucleating agent. A preparation method for the polypropylene modifier comprises: enabling polar monomer grafted polypropylene to be in contact with a component A to react and carrying out extruding pelletizing, wherein a polar monomer in the polar monomer grafted polypropylene can chemically react with the component A; the polar monomer is selected from at least one of dimethylamino methacrylate, epoxy acrylate, trimeric acrylic isocyanurate, and acrylamide; and the component A is selected from at least one of polyisocyanate, polyethylene oxide, and an amido-containing substance. The foamed polypropylene has an obtained foaming ratio of 12 times or more, and also has high tensile and flexural properties.

Molded articles contain a foam composed of a thermoplastic elastotner (TPE-1). The foam has a storage modulus (G modulus) at 25° C. and 1 Hz within the range from 0.01 to 0.5 MPa, a molding density within the range from 20 to 400 kg/m.sup.3, and a comfort factor of greater than 4. A process produces molded articles of this kind, and the molded article can be used for producing floors, mattresses, seating furniture, bicycle saddles, car seats, motorcycle seats, components of a shoe, shoe inserts, packaging, shock absorbers, protectors, fall protection mats, elastic insulating material, or sealing material.

The present invention relates to: a polyolefin-based resin foam including a polyolefin-based resin and a conductive filler containing carbon nanotubes and carbon black, wherein the weight ratio of the carbon nanotubes to the carbon black is about 1:1.5 to about 1:5; and a molded product produced therefrom. The polyolefin-based resin foam according to the present invention includes the carbon nanotubes and the carbon black in an appropriate ratio, and thus a molded product having good bondability and exhibiting low surface resistance and surface resistance deviation can be produced by molding the same.

The invention concerns a process and a device for producing a particle foam part. The method comprises the steps of feeding foam particles into a mould space of a mould, welding the foam particles in the mould space under application of a predetermined pressure, wherein the foam particles comprise a proportion of at least 10% by weight of recycled, shredded foam particles and the welding of the foam particles takes place by means of electromagnetic waves.

The invention concerns a process and a device for producing a particle foam part. The method comprises the steps of feeding foam particles into a mould space of a mould, welding the foam particles in the mould space under application of a predetermined pressure, wherein the foam particles comprise a proportion of at least 10% by weight of recycled, shredded foam particles and the welding of the foam particles takes place by means of electromagnetic waves.