Mitsubishi Rayon Company, Limited

Syoji Imao

Munehiro Okumura

Fujio Itani

Masayuki Igawa

Tokuo Shinomiya

Michisuke Edamatsu

Toshi Yoshihara

Yoshiaki Taniyama

Yoshihiro Osajima

Takeshi Uotani

Sirou Mihara

Masahiko Miyanoki

Flake- or sliver-like porous structures of a polymeric material heavily loaded with a finely divided inorganic substance are prepared by spurting a mixture of the polymeric and finely divided inorganic components in a solvent. The products have many fine, irregular voids. The thickness of walls forming such voids is 5.mu. or less. The products are especially useful for producing sheet-like structures therefrom by beating and/or refining them followed by general paper making procedures. The sheets, when calendered, have a high initial modulus and improved dimensional stability.

Flake- or sliver-like porous structure of polymeric material and process

A process is disclosed whereby porous flakes usable for making paper-like sheets are produced by melting a 10 to 75 parts by weight of thermoplastic polymer, dispersing 25 to 90 parts by weight of finely divided inorganic particles in a solvent capable of dissolving the polymer in an amount of 80 to 95% based on a total weight of the polymer, the inorganic particles and the solvent, at room temperature or lower to prepare a slurry. At a temperature at which the polymer can be dissolved in the solvent, the polymer melt is mixed with the slurry which has been preliminarily heated to a temperature pertinent for realizing the above-mentioned dissolving temperature when the heated slurry is mixed with the polymer melt, to prepare a uniform dispersion of the inorganic particles in the polymer solution in the solvent and then, the dispersion is spurted from a closed tank through an orifice, into a zone having a temperature and pressure lower than that of the dispersion, whereby the spurted dispersion is converted to composite porous flakes by rapidly evaporating the solvent.

Process for continuously producing composite porous flakes

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Otake, Japan

Syoji Imao