Mitsubishi Chemical Corporation

Mitsubishi Kasei Corporation

Kazuyoshi Mino

Katsuji Tanaka

Yoshihiro Fujimori

Toshiyuki Hamano

Takashi Nakamura

Hitoshi Matsumoto

Takuji Hirahara

Michiko Yoshida

Shuuji Anno

Yuka Nakazima

Disclosed are a polyester mainly composed of an aromatic dicarboxylic acid as an acid component and an aliphatic diol as a diol component, wherein the content of an antimony element in the polyester is from 50 to 350 ppm, the number of metallic antimony particles having a diameter of 0.5 &mgr;m or more is 30,000 or more per 100 mg of polyester, the ratio of the number of fine particles having a diameter of 0.5 &mgr;m to less than 0.6 &mgr;m is 70% or more, and the L value in hue is 80 or more; a stretch blow molded product formed of the polyester; and a method for producing a polyester mainly composed of an aromatic dicarboxylic acid as an acid component and ethylene glycol as a diol component which comprises adding a preliminary mixed catalyst solution of an antimony compound and a trivalent phosphorus compound as a catalyst, the catalyst solution having a haze of 10% or less, at a stage showing an acid value of 1,000 eq/ton or less before initiation of melt polymerization.

Polyester, stretch blow molded product formed thereof and method for producing polyester

A polyester which is characterized in that

Polyester and process for its production

A process for producing polyethylene terephthalate comprises the following steps 1 and 2:

Process for producing polyethylene terephthalate

A copolyester comprising a dicarboxylic acid component comprising (a) 80 to 99.5 mol % of terephthalic acid or an ester forming derivative thereof and (b) 0.5 to 4.5 mol % of a phenylenedioxy diacetic acid or an ester forming derivatives thereof and a diol component is described. Hollow containers and stretched film produced from the copolyester are further described. The copolyester has a high transparency, superior gas barrier property, mechanical strength, water resistance and heat resistance. In addition, since the copolyester has a low oligomer content, it scarcely contaminates a mold used in molding process, which leads to a high productivity. The molded article produced from the copolyester can be used widely as packaging materials including various films, sheets and containers. Moreover, since a molded article having superior properties is obtained form the copolyester alone, it is possible to manufacture various packaging materials without using a complicated apparatus and complicated process.

Copolyester and hollow container and oriented film comprising the

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Yokohama, Japan

Kazuyoshi Mino