Sekisui Plastics Co., Ltd.

Sekisui Kaseihin Kogyo Kabushiki Kaisha

Ikuo Morioka

Hideyasu Matsumura

Hiroyuki Yamagata

Mutsuhiko Shimada

Yasutaka Tsutsui

Yukio Aramomi

Takaaki Hirai

Hiroyuki Ueno

Minoru Fujishima

Naokuni Inada

Expandable polystyrenic resin particles having superior resistance to cracking of a molded foam product, having superior retention of blowing agent and maintaining expandability over a long period of time, a production process thereof, and a molded foam product are provided. These expandable polystyrenic resin particles contain a volatile blowing agent in polystyrenic resin particles obtained by impregnating and polymerizing a styrenic monomer in polyolefin resin particles to form a polystyrenic resin, wherein together with the styrenic monomer being used at 140 to 600 parts by weight to 100 parts by weight of the polyolefin resin particles, the average thickness of the surface layer observed in scanning electron micrographs obtained by immersing sections cut into halves through the center from the surface of the resin particles in tetrahydrofuran followed by extracting the polystyrenic resin component and capturing cross-sections of said sections is 15 to 150 &#x3bc;m, and the volatile blowing agent is contained at 5.5 to 13.0% by weight.

Expandable polystyrenic resin particles and production process thereof, pre-expanded particles and molded foam product

A pre-expanded beads of olefin-modified polystyrene-based resin comprising a pie-expanded beads of a polystyrene-based resin modified with a polyolefin-based resin, wherein a styrene-based monomer forming a polystyrene-based resin in the beads is used in the range of 100 to 1,000 parts by weight relative to 100 parts by weight of a polyolefin-based resin, a bulk density of each bead is 0.012 to 0.20 g/cm, and an absorbance ratio at 698 cmand 2850 cm(D/D) obtained from an infrared absorption spectrum of each bead surface measured by ATR method infrared spectroscopy is in the range of 0.1 to 2.5.

Pre-expanded particle of olefin-modified polystyrene resin, process for producing the same, and molded foam

The present invention provides a process for producing a molded foam article of a crystalline aromatic polyester resin. The process is characterized by heating the surface temperature of a mold for cavity-molding to the temperature within a range of from (td&plus;35) to (Tg&plus;57)&deg;C. (Tg is a glass transition temperature of the crystalline aromatic polyester resin prepuffs), thereby to mold prepuffs, and cooling the surface of the mold to a temperature not lowered than Tg for at least 20 seconds.

Method for producing foamed-in-mold product of aromatic polyester based resin

A foamed styrene resin material has a density .rho. of 0.02 to 0.008 and a melt tension of the styrene resin of 5 to 40 gf. The relation between an average cell diameter d (.mu.m) and the density .rho. is given by the expression: ##EQU1## and a relation between a thermal conductivity .lambda. (kcal/m.multidot.h.multidot..degree. C.) and the density .rho. given by the expression: ##EQU2## Accordingly, the foamed styrene resin material has a low thermal conductivity and excellent insulating property in spite of a low density (high expansion ratio foam) thereof.

Foamed styrene resin material and heat insulating material using the

A foamed article of styrene type resin, in which base resin particles are styrene type resin particles obtainable by a graft polymerization of a cis-rich polybutadiene with a styrene type monomer, a blowing agent contains n-pentane as its main component and the foamed article shows a density of 0.015-0.040 g/cm.sup.3, an average foam diameter of 60-300 micrometers and a closed cell foam rate of not less than 50%.

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Nara, Japan

Ikuo Morioka