A method for the production of cellular plastic particles comprising the steps: providing a plastic material in the form of compact plastic material particles, loading of the compact plastic material particles with at least one blowing agent under the influence of pressure, expanding the plastic material particles loaded with at least one blowing agent to produce cellular plastic particles under the influence of temperature.

A method for preparing cellular plastic particles comprising the steps: providing a plastic material in the form of pre-expanded plastic material particles, loading of the pre-expanded plastic material particles with a blowing agent under the influence of pressure, expanding the pre-expanded plastic material particles loaded with a blowing agent for the production of cellular plastic particles, in particular cellular plastic particles with lower density, under the influence of temperature, wherein the expanding of the plastic material particles loaded with blowing agent under the influence of temperature is carried out by irradiating the plastic material particles loaded with blowing agent with high-energy thermal radiation, in particular infrared radiation.

An apparatus and a method for expanding a slurry of thermally expandable thermoplastic microsphere is disclosed. The apparatus and method expand the slurry of thermally expandable thermoplastic microsphere without any direct contact to a fluid heat transfer medium. The apparatus and method utilize a distribution pipe attached to an outlet pipe.

A method for producing polyethylene-based resin foamed particles includes a first-step foaming process. The first-step foaming process includes: producing an aqueous dispersion by dispersing polyethylene-based resin particles in an aqueous dispersing medium in a sealed vessel, adding a carbon dioxide-containing foaming agent to the aqueous dispersion in the sealed vessel, heating and pressurizing the aqueous dispersion in the sealed vessel, and releasing the aqueous dispersion in the sealed vessel to a pressure region where a pressure is lower than an internal pressure of the sealed vessel. The foaming ratio in the first-step foaming process is 10 to 18 times. The polyethylene-based resin particles have a polyethylene-based base resin and a melting point of 105 to 125 C., a tan of 0.3 to 0.7, and a complex viscosity of 5000 to 20000 Pa.Math.s.

Decorative foamed articles are prepared from foamed pellets, beads, particles, or other articles of a thermoplastic elastomer infused with a supercritical fluid in a pressurized container, then rapidly depressurized and heated either by immersion in a heated fluid that can rapidly heat the article or with infrared or microwave radiation to heat and foam the pellets, beads, particles, or other articles that are then molded into the articles. The pellets are dyed with a nonionic or anionic dye one of: (1) before being infused with the supercritical fluid, (2) during being infused with the supercritical fluid by a nonionic or anionic dye dissolved or dispersed in the supercritical fluid, which optionally comprises a polar liquid, (3) during immersion in the heated fluid, where the heated fluid contains the dye, or (4) after being foamed.

Carbon black-containing composite resin pre-expanded particles comprising 100 to 400 parts by mass of a polystyrene-based resin with respect to 100 parts by mass of a carbon black-containing polyolefin-based resin; having a carbon black content of 0.5 to 5.0% by mass and a bulk density of 0.015 to 0.25 g/cm.sup.3; and having an outermost layer of 30 to 80 pm after undergoing the following tests: (a) one of the carbon black-containing composite resin pre-expanded particles is sliced into a 1-mm slice in such a way that cross-section surfaces of cells are exposed on both surfaces of the slice; (b) the obtained slice is immersed in toluene at 25 C. for 24 hours to extract a polystyrene-based resin component as described above; (c) the cross-section surface of the slice is then subjected to magnified photographing by a microscope; (d) the obtained microscope image is observed.

A polypropylene-based resin expanded bead having a tubular shape with a through-hole, containing a foamed core layer constituted by a polypropylene-based resin and a fusion-bonding layer covering the foamed core layer. An average hole diameter d of the through-hole in the expanded bead is less than 1 mm, and a ratio d/D of the average hole diameter d to an average outer diameter D of the expanded bead is 0.4 or less, a mass ratio of the foamed core layer and the fusion-bondable layer is foamed core layer:fusion-bondable layer=99.5:0.5 to 85:15, and the polypropylene-based resin constituting the foamed core layer has a flexural modulus of 800 MPa or more and less than 1200 MPa and a melting point Tmc of 150? C. or lower.

Thermoplastic resin foamed particles of the present invention including more than one functional additive selected from inorganic powder and inorganic fibers each includes a core layer formed of a thermoplastic resin and a coating layer in a foamed state formed of a thermoplastic resin, the mass ratio of the coating layer to the core layer is 99:1 to 50:50, the content (X) of the functional additive in the core layer is 5 to 90% by mass, and the content of the functional additive in the coating layer is smaller than the content (X) of the functional additive in the core layer. By this way, thermoplastic resin foamed particles from which a homogeneous foamed particle molding having excellent dimension stability, fusibility and appearance can be obtained while containing functional additive are provided.

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.

A method for producing polypropylene-based resin expanded beads includes dispersion, blowing agent impregnation, and foaming steps. Beads used in the dispersion step include a core layer having a polypropylene-based resin as a base material resin, and a fusion-bonding layer covering core layer; the beads fusion-bonding layer includes carbon black and a NOR-type hindered amine; a carbon black blending ratio is adjusted to 0.5 wt % or more and 5 wt % or less; and an amine blending ratio of the beads is adjusted to 0.03 wt % or more and 0.5 wt % or less; the polypropylene-based resin expanded beads have a surface on which a fusion-bonding layer is located; the fusion-bonding layer includes the carbon black and hindered amine; a carbon black blending ratio is 0.5 wt % or more and 5 wt % or less; and a blending ratio of the hindered amine is 0.03 wt % or more and 0.5 wt % or less.