A HIPE foam may including a vinyl-based crosslinked polymer as a base material resin. The vinyl-based crosslinked polymer may be formed by crosslinking a polymer of a styrene-based monomer and/or an acryl-based monomer. An apparent density ρ of the HIPE foam may be 35 kg/m.sup.3 or more and 500 kg/m.sup.3 or less. A molecular weight between crosslinking points of the vinyl-based crosslinked polymer forming the HIPE foam may be 2×10.sup.3 or more and 2×10.sup.5 or less. The HIPE foam may be used as, for example, a machinable material or an impact absorbing material.

A HIPE foam may including a vinyl-based crosslinked polymer as a base material resin. The vinyl-based crosslinked polymer may be formed by crosslinking a polymer of a styrene-based monomer and/or an acryl-based monomer. An apparent density ρ of the HIPE foam may be 35 kg/m.sup.3 or more and 500 kg/m.sup.3 or less. A molecular weight between crosslinking points of the vinyl-based crosslinked polymer forming the HIPE foam may be 2×10.sup.3 or more and 2×10.sup.5 or less. The HIPE foam may be used as, for example, a machinable material or an impact absorbing material.

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 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.

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 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.

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.

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.

A method of freeze-drying comprising rapidly freezing either liquid or supercritical carbon dioxide in and around a material having pores at a rate of at least 0.2° C./min to limit the size of crystals formed from the carbon dioxide so as to avoid the formation of gas bubbles and damage to the pores and exposure of the material to gas-liquid interfaces. During freezing a solid layer primarily of solid carbon dioxide is formed on and surrounding the material by transferring heat with a cryogenic liquid circulating about the material. This solid layer protects the material from gas-liquid interfaces and surface tension before decreasing pressure about the material by venting carbon dioxide.

A method of freeze-drying comprising rapidly freezing either liquid or supercritical carbon dioxide in and around a material having pores at a rate of at least 0.2° C./min to limit the size of crystals formed from the carbon dioxide so as to avoid the formation of gas bubbles and damage to the pores and exposure of the material to gas-liquid interfaces. During freezing a solid layer primarily of solid carbon dioxide is formed on and surrounding the material by transferring heat with a cryogenic liquid circulating about the material. This solid layer protects the material from gas-liquid interfaces and surface tension before decreasing pressure about the material by venting carbon dioxide.