Idemitsu Petrochemical Co., Ltd.

Kazuo Minato

Kazuhisa Kaneda

Nobuo Kusamoto

Takao Inokuchi

Tohru Nishi

Yasuji Kawamura

Haruki Kai

Fumio Imaizumi

Toshitaka Kanai

A powdered leather which is composed of at least 85% by weight of cortex, at most 2% by weight of oil and fat, and at most 0.5% by weight of Na.sup.+ and Ca.sup.2+ ions capable of being eluted by water and which has an average particle size (D.sub.50) of at most 7 .mu.m, a standard deviation of the average particle size being at most 3 .mu.m. With this powdered leather, it is possible to thin films, coatings, fibers, etc. which would hardly be deteriorated with time. The powdered leather is produced by providing a powdered leather raw material, grinding the raw material into coarse particles, drying the coarse particles, defatting the dried coarse particles using a solvent, removing the residual solvent from the defatted coarse particles, rinsing the resultant coarse particles, dewatering the rinsed coarse particles, swelling the dewatered coarse particles in steam, redrying the swelled coarse particles, pulverizing the redried coarse particles, classifying the pulverized particles into fine powder and coarse powder, and repulverizing the fine powder so as to have an average particle size (D.sub.50) of at most 7 .mu.m.

Powdered leather and method of producing the same

A cylindrical stabilizing means (stabilizer) for resin bubbles useful to perform shaping of tubular films without causing the fluctuation or breakage of resin bubbles even in case where a take up velocity of the tubular film is relatively large, cooling of tubular body of molten resin extrudated from a die is not sufficient or amount of extrudate from a die is relatively large, is provided. Said stabilizing means has penetration holes on the circumferential wall close to the annular slit 16 of die, which communicate with an opening of the tip of the means, and also has continuous deep grooves of a depth of 0.5 mm or more extending from the portion of the circumferential wall close to said annular slit to the opening of the tip, which grooves are formed on the whole outer circumferential wall having fine concave and convex engraved patterns of the difference of height or depth of from 0.1 mm to 0.5 mm.

Stabilizer for resin bubbles

Growing community of inventors

Tokyo, Japan

Kazuo Minato