| 摘要 |
PURPOSE:To obtain a heat insulating thermoplastic resin foam capable of permanently sustaining a low thermal conductivity, by homogeneously dispersing fine powder having a specific value or above of reflectance of infrared rays in cell walls of a thermoplastic resin foam having a homogeneous and fine closed cell foam structure. CONSTITUTION:A heat insulating thermoplastic resin foam, obtained by melting (A) 100pts.wt. thermoplastic resin, preferably styrene based or olefin based resin and (B) 0.5-20pts.wt., preferably 1-12pts.wt. fine powder having >=40% average value of diffusion reflectance of infrared rays at 6-14mu wavelength, preferably graphite powder, preferably having the surface treated with a coupling agent, e.g. silane based or titanium based coupling agent, etc., using a twin-screw extruder, etc., while heating, injecting a foaming agent, preferably flon based foaming agent, kneading the resultant blend, cooling the kneaded blend to a suitable temperature, extruding and expanding the cooled blend into a zone under a low pressure to provide >=15 times expansion ratio and >=80% closed cell ratio and containing the powder (B) homogeneously dispersed in cell walls thereof.
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