The present invention provides expanded beads of thermoplastic polyurethane, wherein the thermoplastic polyurethane constituting the expanded beads is an ether-based thermoplastic polyurethane, and a difference (T.sub.1−T.sub.2) between a melting peak temperature (T.sub.1) and a melting peak temperature (T.sub.2) is from 0 to 8° C., wherein the melting peak temperature (T.sub.1) is a melting peak temperature at the time of first heating in a DSC curve obtained by heating the expanded beads from 20° C. to 260° C. at a heating rate of 10° C./min, the melting peak temperature (T.sub.2) is a melting peak temperature at the time of second heating in a DSC curve obtained by cooling from 260° C. to 20° C. at a cooling rate of 10° C./min after the first heating and further heating again from 20° C. to 260° C. at a heating rate of 10° C./min, and the DSC curves are obtained by the heat flux differential scanning calorimetry in conformity with JIS K7121-1987. The expanded beads of thermoplastic polyurethane not only have excellent surface appearance and fusion bonding properties but also have a low shrinkage factor.

Expanded beads are those including a mixture of an olefin-based thermoplastic elastomer and a polyethylene-based resin, wherein a melt flow rate MFR(I) of the olefin-based thermoplastic elastomer is 2-10 g/10 min; a difference ((MFR(II))−(MFR(I))) between a melt flow rate MFR(II) of the polyethylene-based resin and the melt flow rate MFR(I) of the olefin-based thermoplastic elastomer is 1-35 g/10 min; and a content of the polyethylene-based resin in the mixture is 3-40% by weight.

Expanded beads are those including a mixture of an olefin-based thermoplastic elastomer and a polyethylene-based resin, wherein a melt flow rate MFR(I) of the olefin-based thermoplastic elastomer is 2-10 g/10 min; a difference ((MFR(II))−(MFR(I))) between a melt flow rate MFR(II) of the polyethylene-based resin and the melt flow rate MFR(I) of the olefin-based thermoplastic elastomer is 1-35 g/10 min; and a content of the polyethylene-based resin in the mixture is 3-40% by weight.

A method for manufacturing semi-conductive polypropylene resin foamed particles of the present invention comprises the steps of: allowing carbon nanotubes to be adsorbed on surfaces of polypropylene resin composition pellets to manufacture carbon nanotube-adsorbed pellets (CNT-PP); and foaming the carbon nanotube-adsorbed pellets (CNT-PP) to form foamed particles.

A method for manufacturing semi-conductive polypropylene resin foamed particles of the present invention comprises the steps of: allowing carbon nanotubes to be adsorbed on surfaces of polypropylene resin composition pellets to manufacture carbon nanotube-adsorbed pellets (CNT-PP); and foaming the carbon nanotube-adsorbed pellets (CNT-PP) to form foamed particles.

Disclosed herein is a process for the production of poly(meth)acrylimide materials. Therein, a granulated copolymer of (meth)acrylic acid and (meth)acrylonitrile is prefoamed and imidated by thermal treatment in a single step to provide poly(meth)acrylimide particles.

Disclosed herein is a process for the production of poly(meth)acrylimide materials. Therein, a granulated copolymer of (meth)acrylic acid and (meth)acrylonitrile is prefoamed and imidated by thermal treatment in a single step to provide poly(meth)acrylimide particles.

The invention refers to a method for producing expanded polymer pellets, which comprises the following steps: melting a polymer comprising a polyamide; adding at least one blowing agent; expanding the melt through at least one die for producing an expanded polymer; and pelletizing the expanded polymer. The invention further concerns polymer pellets produced with the method as well as their use, e.g. for the production of cushioning elements for sports apparel, such as for producing soles or parts of soles of sports shoes. A further aspect of the invention concerns a method for the manufacture of molded components, comprising loading pellets of an expanded to polymer material into a mold, and connecting the pellets by providing heat energy, wherein the expanded polymer material of the pellets or beads comprises a chain extender. The molded components may be used in broad ranges of application.

The invention refers to a method for producing expanded polymer pellets, which comprises the following steps: melting a polymer comprising a polyamide; adding at least one blowing agent; expanding the melt through at least one die for producing an expanded polymer; and pelletizing the expanded polymer. The invention further concerns polymer pellets produced with the method as well as their use, e.g. for the production of cushioning elements for sports apparel, such as for producing soles or parts of soles of sports shoes. A further aspect of the invention concerns a method for the manufacture of molded components, comprising loading pellets of an expanded to polymer material into a mold, and connecting the pellets by providing heat energy, wherein the expanded polymer material of the pellets or beads comprises a chain extender. The molded components may be used in broad ranges of application.

A foaming resin composition of the present invention contains an aromatic vinyl-based resin and zinc oxide, wherein the size ratio (B/A), in which peak A is a 370 nm to 390 nm region and peak B is a 450 nm to 600 nm region, of zinc oxide is approximately 0.01 to approximately 1 when photoluminescence is measured, and the BET surface area thereof is approximately 1 m.sup.2/g to approximately 10 m.sup.2/g.