Konica Corporation

Kanebo, Limited

Konishiroku Photo Industry Co., Ltd.

Ichiya Harada

Kazuto Kiyohara

Toshiaki Yamazaki

Takanori Nakadate

Kentaro Noguchi

Shigeru Sakae

Kazuhiro Okuma

Hiroshi Naito

Hiromitsu Araki

Yoshihiro Wada

Toshiyuki Hagiwara

Yoshimichi Ozawa

Michiteru Nakano

Hitoshi Kawamoto

Disclosed are a white polyester composition comprising a polyester containing a titanium dioxide, and the titanium dioxide being one subjected to a heat treatment at a temperature of 350.degree. C. or higher after at least one of an inorganic surface treatment and an organic surface treatment, and a support for photography having a polyester layer comprising the white polyester composition.

White polyester composition and support for photography

There is disclosed a copolyester which comprises at least four compositions of: (A) terephthalic acid, and/or its ester forming derivative (terephthalic acid component) and isophthalic acid and/or its ester forming derivative (isophthalic acid component) with a molar ratio of 30/70 to 70/30; (b) 5 to 15 mole % of a dicarboxylic acid having sulfonate group and/or its ester forming derivative based on the all dicarboxylic acid components; (C) an alicyclic dicarboxylic acid and/or its ester forming derivative; and (D) 50 mole % of ethylene glycol based on the all glycol components; and a polyester film which comprises a subbing layer containing the copolyester provided on at least one side of a polyester film base.

Copolyester and polyester film having said copolyester as subbing layer

A process for producing a polyester resin composition containing at least 10 wt % of a white inorganic pigment dispersed in a polyester resin, which comprises kneading the polyester resin with the white inorganic pigment and thereafter subjecting the blend to a polycondensation reaction at a temperature ranging from the melting point of the polyester up to 300.degree. C. and at a reduced pressure of not higher than 5 Torr, is disclosed.

Process for producing polyester resin composition

A process for producing a titanium dioxide containing polyester resin composition from which a white film useful as a reflective photographic support can be prepared is disclosed. Said process is performed by first supplying a polyester resin and titanium dioxide into a continuous kneading extruder, kneading them in molten state, and supplying an additional charge of the polyester resin to give a desired concentration of the titanium dioxide, wherein the first supplied polyester resin has an intrinsic viscosity of at least 0.40, said titanium dioxide having an average particle size of 0.1-0.5 .mu.m and a water content of no more than 0.5% and having been surface-treated with an aluminum compound and/or a silicon compound, and the concentration of titanium dioxide being in the range of 20-70 wt % when kneaded with the polyester resin in molten state.

A method of manufacturing a photographic reflecting support wherein chips and/or resin scraps of a thermoplastic resin are heat-treated in a vacuum and fed into an extruder to be melted and then extruded in the form of a sheet out of the die of the extruder. The resulting sheet is then cooled and solidified on a cooled casting drum and stretched 6 to 16 times in terms of area, lengthwise and then widthwise or vice versa, or biaxially at the same time, at a temperature within the range of from a temperature not lower than the glass transition point of the thermoplastic resin to a temperature not higher than 150.degree. C. The stretched sheet is then thermoset at a temperature within the range of from a temperature not lower than 170.degree. C. to a temperature of the melting point of the thermoplastic resin and the resulting photographic reflecting support is made from 40 .mu.m to 300 .mu.m in thickness and not higher than 20% in visible-wave-length range transmittance.

Method of manufacturing a photographic reflecting support

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Hino, Japan

Ichiya Harada