Composite resin particles comprising 50 to 800 parts by mass of a polystyrene-based resin with respect to 100 parts by mass of a polyolefin-based resin, wherein: when transmission electron microscope (TEM) images obtained by photographing cross-sections of the composite resin particles using a TEM at a magnification of 1,000 are subjected to a binarization processing and areas in the obtained binarized images which correspond to a cross-sectional area of 437.584 μm.sup.2 of the composite resin particles are subjected to image analysis, the polystyrene-based resin satisfies the following requirements: (1) the number of dispersed particles is 180 or more; (2) the maximum of the areas of dispersed particles is 200 μm.sup.2 or less; and (3) the coefficient of variation in dispersion is 100% or more, and the composite resin particles exhibit an inner morphology that includes a mixture of sea-island structure regions and co-continuous structure regions.

Expandable styrene composite polyolefin-based resin particles which comprise styrene composite polyolefin-based resin particles containing a polyolefin-based resin and 100 to 400 parts by mass of a styrene-based resin with respect to 100 parts by mass of the polyolefin-based resin and comprise butane/pentane in a mass ratio of 80/20 to 50/50 as a volatile blowing agent.

Expandable styrene composite polyolefin-based resin particles which comprise styrene composite polyolefin-based resin particles containing a polyolefin-based resin and 100 to 400 parts by mass of a styrene-based resin with respect to 100 parts by mass of the polyolefin-based resin and comprise butane/pentane in a mass ratio of 80/20 to 50/50 as a volatile blowing agent.

An expanded polypropylene resin particle includes a polypropylene resin composition that serves as a base material resin. The polypropylene resin composition includes a first polypropylene resin having a melting point of 140° C. or less, a second polypropylene resin having a melting point of 145° C. or more, and a polyethylene resin having a melting point of 120° C. to 135° C. The first polypropylene resin accounts for 50 to 75 weight %, the second polypropylene resin accounts for 25 to 50 weight %, and the polyethylene resin accounts for 1 to 10 weight %, wherein the weight % is based on a total amount of the first polypropylene resin, the second polypropylene resin, and the polyethylene resin.

An expanded polypropylene resin particle includes a polypropylene resin composition that serves as a base material resin. The polypropylene resin composition includes a first polypropylene resin having a melting point of 140° C. or less, a second polypropylene resin having a melting point of 145° C. or more, and a polyethylene resin having a melting point of 120° C. to 135° C. The first polypropylene resin accounts for 50 to 75 weight %, the second polypropylene resin accounts for 25 to 50 weight %, and the polyethylene resin accounts for 1 to 10 weight %, wherein the weight % is based on a total amount of the first polypropylene resin, the second polypropylene resin, and the polyethylene resin.

An intumescent polymer is provided for molding fire-retardant structures. Expandable graphite is mixed in a polymer matrix to form the intumescent polymer. The expandable graphite is treated with silane to improve the strength of the polymer. Other ingredients may also be included within the polymer, including an acid source, blowing agent, char forming agent, an inorganic filler and a cross-linking agent.

An intumescent polymer is provided for molding fire-retardant structures. Expandable graphite is mixed in a polymer matrix to form the intumescent polymer. The expandable graphite is treated with silane to improve the strength of the polymer. Other ingredients may also be included within the polymer, including an acid source, blowing agent, char forming agent, an inorganic filler and a cross-linking agent.

Foamed pellets contain a thermoplastic polyurethane obtainable or obtained by reacting a polyisocyanate composition (IC), containing at least one aliphatic diisocyanate having a number-average molecular weight of less than 200 g/mol, at least one chain extender (CE1), and a polyol composition (PC). A process can be used for the production of such foamed pellets. The foamed pellets can be used for the production of a molded body.

Foamed pellets contain a thermoplastic polyurethane obtainable or obtained by reacting a polyisocyanate composition (IC), containing at least one aliphatic diisocyanate having a number-average molecular weight of less than 200 g/mol, at least one chain extender (CE1), and a polyol composition (PC). A process can be used for the production of such foamed pellets. The foamed pellets can be used for the production of a molded body.

A modified expanded bead that includes an expanded bead which includes a specific base polymer (β) and a coating layer which includes a specific base polymer (α). The coating layer covers at least part of an outer surface of the expanded bead. The melting point Tα of the base polymer (α) and the melting point Tβ of the base polymer (β) satisfy a relationship of 0≤Tα−Tβ≤20. When the modified expanded bead is cut into two halves along a cutting plane to form two half portions and thereafter one of the two half portions is cut along planes perpendicular to the cutting plane to form ten small pieces, outermost pieces among the ten small pieces have a xylene-insoluble content (B) which is less than a xylene-insoluble content (A) in the half portion and the xylene-insoluble content (A) is 10-80% by mass.