Expanded polypropylene beads are prepared from composite particles using a high-temperature and high-pressure kettle type foaming method. The composite particles include a core layer and a skin layer. The core layer includes one or more of the following components, for example in percentage by mass: 20-40% of polypropylene A, 60-80% of polypropylene B, 0-20% of polypropylene C and 0-10% of a thermal-conductive additive. The skin layer includes one or more of the following components, for example in percentage by mass: 40-80% of polypropylene D and 20-60% of polypropylene E. The composite particles are of a multi-layer structure with the skin layer covering the core layer. A resin of the skin layer is easy to sinter at low temperature and in compatibility with a main substrate resin of the core layer. The core layer resin adopts a selected mixture, which promotes molding expansibility.

Expanded polypropylene beads are prepared from composite particles using a high-temperature and high-pressure kettle type foaming method. The composite particles include a core layer and a skin layer. The core layer includes one or more of the following components, for example in percentage by mass: 20-40% of polypropylene A, 60-80% of polypropylene B, 0-20% of polypropylene C and 0-10% of a thermal-conductive additive. The skin layer includes one or more of the following components, for example in percentage by mass: 40-80% of polypropylene D and 20-60% of polypropylene E. The composite particles are of a multi-layer structure with the skin layer covering the core layer. A resin of the skin layer is easy to sinter at low temperature and in compatibility with a main substrate resin of the core layer. The core layer resin adopts a selected mixture, which promotes molding expansibility.

Expanded polypropylene beads comprising a polypropylene composition (C) having: a) a melt flow rate (MFR2) in the range from 1.5 to 15.0 g/10 min; b) a melting temperature (Tm) in the range from 135 to 158° C.; and c) a loss tangent (tan δ) in the range of 2.00 to 4.00 wherein the polypropylene composition (C) comprises more than 90.0 wt.-%, of a long chain branched copolymer of propylene (c-PP) comprising up to 8.0 wt.-% of comonomer(s) selected from ethylene and C.sub.4 to C.sub.10 alpha olefins, a method for the preparation of said beads, in addition to a method of forming molded articles from said beads, and the molded articles obtained thereby.

Expanded polypropylene beads comprising a polypropylene composition (C) having: a) a melt flow rate (MFR2) in the range from 1.5 to 15.0 g/10 min; b) a melting temperature (Tm) in the range from 135 to 158° C.; and c) a loss tangent (tan δ) in the range of 2.00 to 4.00 wherein the polypropylene composition (C) comprises more than 90.0 wt.-%, of a long chain branched copolymer of propylene (c-PP) comprising up to 8.0 wt.-% of comonomer(s) selected from ethylene and C.sub.4 to C.sub.10 alpha olefins, a method for the preparation of said beads, in addition to a method of forming molded articles from said beads, and the molded articles obtained thereby.

A molded article of polyolefin-based resin expanded beads having excellent appearance and further suppressed color unevenness is provided.

Polyolefin-based resin expanded beads obtained by expanding polyolefin-based resin particles including one or two or more metal borates selected from zinc borate and magnesium borate, wherein the particles of the metal borate has an arithmetic average particle diameter based on the number of 1 μm or more, and a number rate of the particles of the metal borate having a particle diameter of 5 μm or more is 20% or less. A method for producing polyolefin-based resin expanded beads by releasing expandable polyolefin-based resin particles containing one or two or more metal borates selected from zinc borate and magnesium borate and a physical blowing agent dispersed in an aqueous medium in a closed vessel together with the aqueous medium from the closed vessel to a low pressure region than an inside of the closed vessel to expand the expandable polyolefin-based resin particles, the method comprising: using a metal borate having an arithmetic average particle diameter based on the number of 1 μm or more and a number rate of the particles having a particle diameter of 5 μm or more of 20% or less as the metal borate.

A molded article of polyolefin-based resin expanded beads having excellent appearance and further suppressed color unevenness is provided.

Polyolefin-based resin expanded beads obtained by expanding polyolefin-based resin particles including one or two or more metal borates selected from zinc borate and magnesium borate, wherein the particles of the metal borate has an arithmetic average particle diameter based on the number of 1 μm or more, and a number rate of the particles of the metal borate having a particle diameter of 5 μm or more is 20% or less. A method for producing polyolefin-based resin expanded beads by releasing expandable polyolefin-based resin particles containing one or two or more metal borates selected from zinc borate and magnesium borate and a physical blowing agent dispersed in an aqueous medium in a closed vessel together with the aqueous medium from the closed vessel to a low pressure region than an inside of the closed vessel to expand the expandable polyolefin-based resin particles, the method comprising: using a metal borate having an arithmetic average particle diameter based on the number of 1 μm or more and a number rate of the particles having a particle diameter of 5 μm or more of 20% or less as the metal borate.

A thermally expandable sheet includes: a first thermally expansive layer that is formed on one side of a base and contains a first thermally expandable material; and a second thermally expansive layer that is formed on the first thermally expansive layer and contains a second thermally expandable material, wherein the second thermally expandable material further contains white pigment.

A supported elastomeric foam (100) includes an elastomeric matrix (102) formed of an elastomer and including a reinforcement region (104) and a foamed region (106). The foamed region includes gas filled cells (108) in the elastomer, and the reinforcement region includes a porous layer (204) having an interconnected network of pores at least partially imbibed with the elastomer. The foam can include an adhesive at a surface of the foam. A compressible seal (802) including a compressible body, which can be elastomeric foam, can also include a pattern of discontinuous adhesive regions about which the compressible body can deform to form a sea. The supported elastomeric foam can form a gas tight seal in an interface when placed under minimal compression.

A supported elastomeric foam (100) includes an elastomeric matrix (102) formed of an elastomer and including a reinforcement region (104) and a foamed region (106). The foamed region includes gas filled cells (108) in the elastomer, and the reinforcement region includes a porous layer (204) having an interconnected network of pores at least partially imbibed with the elastomer. The foam can include an adhesive at a surface of the foam. A compressible seal (802) including a compressible body, which can be elastomeric foam, can also include a pattern of discontinuous adhesive regions about which the compressible body can deform to form a sea. The supported elastomeric foam can form a gas tight seal in an interface when placed under minimal compression.

VDF-co-(TFE or TrFE) polymers having a molecular weight of at least about 1,000,000 g/mol and a melt temperature less than about 240° C. The VDF copolymer contains at least about 50 mol % VDF monomer and may include an amount of at least one other monomer. The VDF copolymer may be used to form a membrane that has a node and fibril structure. The membrane has a percent porosity of at least 25%. A VDF-co-(TFE or TrFE) polymer membrane may be formed by lubricating the VDF copolymer, subjecting the lubricated polymer to pressure at a temperature below the melting point of the VDF copolymer to form a preform material, and expanding the preform material at a temperature below the melting temperature of the VDF copolymer. Dense VDF copolymer articles, filled VDF copolymer membranes, and VDF copolymer fibers are also provided.