Mitsui Chemicals, Inc.

Seiji Noda

Junichi Imuta

Shoji Hiraoka

Koji Nakamachi

Satoru Miyazoe

Takayuki Onogi

Hideshi Hori

Fujito Ehara

Kazuo Toyota

Michio Tsugawa

Takeshi Ohmatsuzawa

Kenzaburou Fukutani

Masayuki Sakai

Akiyoshi Shimizu

Akivoshi Shimizu

The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.

Catalyst for polyester production, process for producing polyester using the catalyst, polyester obtained by the process, and uses of the polyester

The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity and a process for producing a polyester using the catalyst. The catalyst for polyester production comprises a solid titanium compound which is obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. The present invention also provides a method to obtain a polyester having a small increase of the acetaldehyde content during the molding. This method comprises bringing a polyester, which is obtained by the use of a titanium compound catalyst and in which the reaction has been completed, into contact with a phosphoric ester aqueous solution or the like having a concentration of not less than 10 ppm in terms of phosphorus atom. The present invention further provides a polyester having excellent transparency and tint and molded products of the polyester such as a blow molded article, a film, a sheet and a fiber. The polyester is obtained by polycondensing an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol or an ester-forming derivative thereof in the presence of a catalyst for polyester production which comprises a polycondensation catalyst component comprising a solid titanium compound and a co-catalyst component comprising a magnesium compound. This polyester has a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a weight ratio (Mg/Ti) of magnesium to titanium of not less than 0.01.

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Seiji Noda