The process for forming closed cell expanded low density polyethylene foam includes the steps of: providing a mixture including low density polyethylene pellets and an effective amount of hydrocarbon scavenger additives or degassing agents, such as glycerides; adding a primary blowing agent comprising one of liquid propane, liquid butane, and combinations thereof, to the mixture and gasifying the blowing agent to expand the low density polyethylene; forming the expanded low density polyethylene into sheets, curing the expanded low density polyethylene until 80%, generally at least 99%, of the primary blowing agent is dissipated from cells within the expanded low density polyethylene forming evacuated closed cell low density polyethylene sheets.

An expanded bead having a through hole and including a foamed core layer which defines the through hole therein and which is constituted of a resin composition containing two kinds of polypropylene-based resins having different melting points, and a cover layer covering the foamed core layer and constituted of a polyolefin-based resin. The expanded bead gives a DSC curve in which an endothermic peak intrinsic to the resin composition and another endothermic peak on a higher temperature side thereof appear in a specific heat of fusion ratio. Molded articles include a multiplicity of the expanded beads.

Polymer foams based on polyetherimides (PEIs) fulfill the legal specifications demanded by the aviation industry for aircraft interiors. Specifically, the demands on fire characteristics, stability to media and mechanical properties constitute a great challenge here. According to related art, suitable polymer foams are produced as semi-finished products. Reprocessing to give shaped articles is uneconomic in terms of time and material exploitation, for example by virtue of large amounts of cutting waste. The material is suitable in principle and can be processed to give particle foam mouldings. These mouldings can be produced without reprocessing in short cycle times and, hence, economically. Furthermore, this gives rise to new means of functional integration, for example by direct incorporation of inserts etc. in the foam, and with regard to freedom in terms of design.

A thermoplastic olefinic elastomer expanded bead, which is an expanded bead including a thermoplastic olefinic elastomer as a main component, wherein the expanded bead has an average particle diameter of 0.5 to 5 mm, the expanded bead has a heat of fusion of 60 to 80 J/g, and a difference [Tm−Tc] between a melting point (Tm) and a crystallization temperature (Tc) of the expanded bead is 20° C. or lower.

The present invention relates to an expanded beads molded article containing a block copolymer of a polyethylene block and an ethylene-α-olefin copolymer block and having a density of 30 kg/m.sup.3 or more and less than 150 kg/m.sup.3 and a modulus of repulsion elasticity of 60% or more. The sole member of the present invention includes the expanded beads molded article of the present invention.

The present disclosure provides a composite material layer including a core layer and a shell layer. The core layer includes foamed elastomers. The shell layer encapsulates the core layer and continuously covered surfaces of the foamed elastomers, wherein the shell layer includes a material having light absorption. The melting point of the core layer is higher than the melting point of the shell layer.

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 method of producing a polyethylene resin expanded molded product includes filling a mold with expanded polyethylene resin particles, wherein an internal pressure of 0.12 to 0.16 MPa is applied to the expanded polyethylene resin particles in the mold, and forming the polyethylene resin expanded molded product by heating the expanded polyethylene resin particles and fusing the expanded polyethylene resin particles. The expanded polyethylene resin particles includes 100 parts by weight of a polyethylene resin, 0.08 to 0.25 parts by weight of a cell nucleating agent, 0.3 to 0.8 parts by weight of a polyhydric alcohol fatty acid ester, and 0.01 to 10 parts by weight of a hydrophilic compound, each of the expanded polyethylene resin particles having a weight of 2.5 to 3.5 mg. The polyethylene resin expanded molded product has a density of 0.017 to 0.021 g/cm.sup.3 and a thickness of 10 to 40 mm.

Provided are composite particles in which reinforcing fibers adhere to the surface of thermoplastic resin expanded beads via a thermosetting resin being in an uncured state, a cured product of the composite particles, an in-mold molded article of the composite particles, a laminate of the composite particles and a reinforcing fiber sheet material, a composite of the composite particles, and a method for producing composite particles.

Low-density thermoplastic expandable microspheres are disclosed. Various low-density structures, in particular, sandwich panels, based on foam prepared from the low-density microspheres, are also disclosed. Process of preparing low-density polymeric microspheres, per se, and the corresponding low-density structures, based on the microsphere foam, are also disclosed.