The present invention is concerned with expanded propylene resin beads including a core layer being in a foamed state and constituted of a propylene-based resin composition (a) and a cover layer constituted of an olefin-based resin (b), the propylene-based resin composition (a) satisfying the following (i) and (ii), and the olefin-based resin (b) satisfying the following (iii) or (iv). (i) A mixture of 75% by weight to 98% by weight of a propylene-based resin (a1) having a melting point of 100 C. to 140 C. and 25% by weight to 2% by weight of a propylene-based resin (a2) having a melting point of 140 C. to 165 C. (ii) A difference between the melting point of the resin (a2) and the melting point of the resin (a1) is 15 C. or more. (iii) A crystalline olefin-based resin having a melting point TmB that is lower than a melting point TmA of the composition (a) and having a relation of 0 C.<[TmATmB]80 C. (iv) A non-crystalline olefin-based resin having a softening point TsB that is lower than TmA and having a relation of 0 C.<[TmATsB]100 C.

The present invention is concerned with expanded propylene resin beads including a core layer being in a foamed state and constituted of a propylene-based resin composition (a) and a cover layer constituted of an olefin-based resin (b), the propylene-based resin composition (a) satisfying the following (i) and (ii), and the olefin-based resin (b) satisfying the following (iii) or (iv). (i) A mixture of 75% by weight to 98% by weight of a propylene-based resin (a1) having a melting point of 100 C. to 140 C. and 25% by weight to 2% by weight of a propylene-based resin (a2) having a melting point of 140 C. to 165 C. (ii) A difference between the melting point of the resin (a2) and the melting point of the resin (a1) is 15 C. or more. (iii) A crystalline olefin-based resin having a melting point TmB that is lower than a melting point TmA of the composition (a) and having a relation of 0 C.<[TmATmB]80 C. (iv) A non-crystalline olefin-based resin having a softening point TsB that is lower than TmA and having a relation of 0 C.<[TmATsB]100 C.

A method of producing a polyamide foam molded article is provided. The method includes: loading polyamide pre-expanded particles containing water in a water content ratio of 0 mass % or more and 12 mass % or less, into a mold; heating the polyamide pre-expanded particles with saturated steam at a temperature equal to or lower than a molding temperature minus 5? C. for 30 seconds or more and 90 seconds or less, the molding temperature being 100? C. or higher; and then thermally fusing the polyamide pre-expanded particles with saturated steam at the molding temperature.

To provide a modified PTFE excellent in heat resistance. The modified polytetrafluoroethylene comprises a polymer having units based on tetrafluoroethylene and a polymer having units based on a fluorine-free monomer, wherein the endothermic amount ratio R calculated by a prescribed method is at least 0.65.

To provide a modified PTFE excellent in heat resistance. The modified polytetrafluoroethylene comprises a polymer having units based on tetrafluoroethylene and a polymer having units based on a fluorine-free monomer, wherein the endothermic amount ratio R calculated by a prescribed method is at least 0.65.

The invention relates to a process for the manufacture of thermally expandable thermoplastic microspheres. The process comprises, providing a mixture of monomeric materials suitable for polymerisation to form a thermoplastic polymer and at least one blowing agent, providing to the mixture a colloidal silica that is surface-modified with at least hydrophobic organosilane groups and forming an emulsion. A polymerisation is performed to form the thermally expandable thermoplastic microspheres. The invention further relates to thermally expandable thermoplastic micro spheres, expanded micro spheres and their use in the manufacture of products.

The invention relates to a process for the manufacture of thermally expandable thermoplastic microspheres. The process comprises, providing a mixture of monomeric materials suitable for polymerisation to form a thermoplastic polymer and at least one blowing agent, providing to the mixture a colloidal silica that is surface-modified with at least hydrophobic organosilane groups and forming an emulsion. A polymerisation is performed to form the thermally expandable thermoplastic microspheres. The invention further relates to thermally expandable thermoplastic micro spheres, expanded micro spheres and their use in the manufacture of products.

The invention relates to a process for the production of prefoamed poly(meth)acrylimide (P(M)I) particles which can be further processed to give foam mouldings or composites. A feature of this process is that a polymer granulate is first heated and thus prefoamed in an apparatus by means of IR radiation of a wavelength suitable for this purpose. Said granulate can be further processed in subsequent steps, e.g. in a press mould with foaming to give a moulding or a composite workpiece with foam core.

The invention relates to a process for the production of prefoamed poly(meth)acrylimide (P(M)I) particles which can be further processed to give foam mouldings or composites. A feature of this process is that a polymer granulate is first heated and thus prefoamed in an apparatus by means of IR radiation of a wavelength suitable for this purpose. Said granulate can be further processed in subsequent steps, e.g. in a press mould with foaming to give a moulding or a composite workpiece with foam core.

Provided is an expanded propylene resin bead including a core layer in a foamed state, which includes a propylene-based resin composition (a) satisfying the following (i) and (ii); and a cover layer which includes an olefin-based resin (b) satisfying the following (iii) or (iv): (i) the propylene-based resin composition (a) is a mixture of 65% by weight to 98% by weight of a propylene-based resin (a1) having a melting point of 145 C. to 165 C. and a flexural modulus of 1,200 MPa or more and 35% by weight to 2% by weight of a propylene-based resin (a2) having a melting point of 100 C. to 145 C. and a flexural modulus of 800 MPa to 1,200 MPa; (ii) a difference in a melting point between the resin (a1) and the resin (a2) is 5 C. to 25 C.; (iii) the olefin-based resin (b) is a crystalline olefin-based resin having a melting point (TmB) that is lower than a melting point (TmA) of the composition (a) and being in a relation of (0 C.<[TmA-TmB]80 C.); and (iv) the olefin-based resin (b) is a non-crystalline olefin-based resin having a softening point (TsB) that is lower than the TmA and being in a relation of (0 C.<[TmATsB]100 C.).