Kureha Corporation

Kureha Kagaku Kogyo K.k.

Toshihiko Ono

Yoshinori Suzuki

Kazuyuki Yamane

Yoshikatsu Satake

Takenori Tose

Haruyasu Yamaji

Hiroyuki Sato

Shigeru Suzuki

Yukio Ichikawa

Fuminori Kobayashi

Kazuhiko Sunagawa

Yuki Hokari

Yoshinobu Itoh

Junji Nakajima

Nanako Saigusa

Yuta Yamadoi

Hiromitsu Miura

Daisuki Itoh

In a method for producing a cyclic ester according to an embodiment of the present invention, a mixture (I) containing an aliphatic polyester, a specific polyalkylene glycol diether, and a sulfonic acid compound as a thermal stabilizer is prepared and heated in predetermined conditions to obtain a mixture (II) in a state of solution. Furthermore, heating of the mixture (II) is continued to distill, together with the polyalkylene glycol diether, a cyclic ester formed by the depolymerization reaction, and thus a distillate (III) is obtained. The cyclic ester is recovered from the distillate (III). At this time, a specific solubilizing agent is added to at least one of the mixture (I) or (II). In this production method, the sulfonic acid compound as the thermal stabilizer is contained in the mixtures (I) and (II) and the distillate (III).

Method for producing cyclic ester

Provided is a method for producing a high purity &#x3b1;-hydroxycarboxylic acid dimeric cyclic ester while heavy-component formation from an &#x3b1;-hydroxycarboxylic acid oligomer is suppressed. An &#x3b1;-hydroxycarboxylic acid dimeric cyclic ester is obtained by performing a depolymerization reaction in the coexistence of an inorganic acid or an inorganic acid salt or a mixture thereof; and an organophosphorus compound.

Method for producing &#x3b1;-hydroxycarboxylic acid dimeric cyclic ester

The object of the present invention is to provide a glycolide production method capable of further increasing the production rate of glycolide. The glycolide production method according to the present invention includes adding metal iron to an aqueous glycolic acid solution, subjecting glycolic acid contained in the aqueous glycolic acid solution to which the metal iron is added, to dehydrating polycondensation to obtain a glycolic acid oligomer, and heating and depolymerizing the glycolic acid oligomer to obtain glycolide.

Glycolide production method

The invention provides a production process of glycolide comprising the respective steps of: Step 1 of heating a mixture containing a glycolic acid oligomer and a high boiling polar organic under normal or reduced pressure to reflux the mixture and at that time, conducting a total reflux operation in a reflux time within a range of 0.1 to 20 hours under conditions that substantially the whole amount of a distillate distilled out of a reflux system containing the mixture is refluxed into the reflux system; Step 2 of heating the mixture after the total reflux operation or a mixture obtained by adding the high boiling polar organic solvent to a glycolic acid oligomer component recovered from the mixture after the total reflux operation to conduct depolymerization; and Step 3 of collecting glycolide from a co-distillate.

Production process of glycolide

An aromatic polyester resin composition, comprising: a melt-kneaded product of 99-70 weight parts of an aromatic polyester resin and 1-30 wt. parts (providing a total of 100 wt. parts together with the aromatic polyester resin) of a polyglycolic acid resin, wherein the composition is characterized by a transesterification rate C(%) of 20-60% determined by formula (1) below based on a peak integration ratio of methylene group in polyglycolic acid appearing at &#x3c3;4.87 ppm with reference to tetramethylsilane according toH-NMR measurement:(%)=(1&#x2212;()/())&#xd7;100&#x2003;&#x2003;(1),wherein I (A): a peak integration ratio of the methylene group of the polyglycolic acid main chain with respect to the alkylene group of the aromatic polyester main chain calculated from the components weight ratio; and I (B): a peak integration ratio of the methylene group of polyglycolic acid main chain to the alkylene group of the aromatic polyester main chain in the resin composition. As a result, the aromatic polyester resin composition obtained by adding a relatively small amount of polyglycolic acid resin is provided with a good harmony of gas-barrier property and transparency.

Aromatic polyester resin composition and process for production thereof

Crystalline polyglycolic acid wherein a difference between the melting point Tm and the crystallization temperature Tcis not lower than 35&#xb0; C., and a difference between the crystallization temperature Tcand the glass transition temperature Tg is not lower than 40&#xb0; C. A production process of polyglycolic acid modified in crystallinity, comprising applying heat history to crystalline polyglycolic acid at a temperature of not lower than (the melting point Tm of the crystalline polyglycolic acid+38&#xb0; C.). A polyglycolic acid composition comprising crystalline polyglycolic acid and a heat stabilizer, wherein a difference (T&#x2212;T) between the temperature Tat 3%-weight loss on heating of the polyglycolic acid composition and the temperature Tat 3%-weight loss on heating of the crystalline polyglycolic acid is not lower than 5&#xb0; C.

Crystalline polyglycolic acid, polyglycolic acid composition and production process thereof

A poly(arylene sulfide) resin composition comprising in admixture a poly(arylene sulfide) resin and at least one nickel compound selected from the group consisting of (a) nickel carbonates, (b) nickel hydroxide, (c) organic carboxylates of nickel and (d) nickel oxide is provided. According to the resin composition of the invention, the metal corrosiveness of the poly(arylene sulfide) resin upon and after its molding or forming is sufficiently inhibited without deteriorating the excellent heat resistance, mechanical properties, processability and the like inherent in the resin.

Poly (arylene sulfide) resin composition

A poly(arylene sulfide) resin composition in which the tendency of a poly(arylene sulfide) resin to cause metals making up molds, processing machinery, metal parts of inserts and the like to corrode has been inhibited, and which has good processability includes the poly(arylene sulfide) resin and, as a corrosion inhibitor, at least one substance selected from the group consisting of a metallic simple substance of molybdenum, oxoacids of molybdenum, alkali metal salts of the oxoacids of molybdenum, alkaline earth metal salts of the oxoacids of molybdenum, the ammonium salts of the oxoacids of molybdenum, the zinc salts of the oxoacids of molybdenum, a metallic simple substance of tungsten, oxoacids of tungsten, alkali metal salts of the oxoacids of tungsten, alkaline earth metal salts of the oxoacids of tungsten, the ammonium salts of the oxoacids of tungsten and the zinc salts of the oxoacids of tungsten. The corrosion inhibitor being incorporated in a proportion within a range of 0.01-10 parts by weight per 100 parts by weight of the poly(arylene sulfide) resin.

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Tokyo, Japan

Toshihiko Ono