Toyo Boseki Kabushiki Kaisha

Hitoshi Furusaki

Yoshio Araki

Yoshinao Matsui

Mitsuhiro Harada

Yoshitaka Eto

Keisuke Suzuki

Hirotoshi Sonoda

Shouji Kikuchi

Takashi Hashimoto

Osamu Kimura

Kazuki Yamauchi

Atsushi Hara

A polyester resin comprising a polyester resin chip (A) and a polyester resin fine particle (B) which has the same composition as the (A) and which passes through a 10.5 mesh screen in a proportion of 0.1-300 ppm, wherein a cyclic trimer increases in a proportion of not more than 0.30 wt % upon melting at a temperature of 290.degree. C. for 60 minutes; a polyester resin characterized in that a cyclic trimer increases in a proportion of not more than 0.30 wt % upon melting at a temperature of 290.degree. C. for 60 minutes, and the contents of Na, Ca, Mg and/or Si in the polyeser resin is 0.001-5 ppm and the total of these contents is not more than 10 ppm; and production methods thereof. According to the polyester resin of the present invention, mold such as stretch blow mold, heat setting mold, vacuum forming mold and the like are less stained in sheet forming, bottle forming and the like, so that forming can be continued for a long time to easily produce a multitude of formed articles with superior transparency. As a result, hollow articles having superior transparency and heat resistance of the finish part can be obtained.

Polyester resin and production method thereof

Growing community of inventors

Tsuruga, Japan

Hitoshi Furusaki