Mitsui Chemicals, Inc.

Mitsui Petrochemical Industries, Ltd.

Nippon Paper Industries Co., Ltd.

Masayuki Sakai

Shoji Hiraoka

Koji Nakamachi

Masanobu Ajioka

Masatoshi Takagi

Shinji Ogawa

Hiroji Niimi

Hiroshi Suizu

Yuji Terado

Hiroyuki Suzuki

Yasushi Kotaki

Hitoshi Tsuboi

Junichi Imuta

Shigemi Shiraki

Satoru Miyazoe

Takayuki Onogi

Hideshi Hori

Fujito Ehara

Kazuo Toyota

Michio Tsugawa

Yasuhiro Tanaka

Takeshi Ohmatsuzawa

Kenzaburou Fukutani

Seiji Noda

Ryo Shinagawa

Koji Takahashi

Eiji Takahashi

Hiroshi Kimura

Hiroshi Inoue

Hiroshi Kondo

Akiyoshi Shimizu

Takashi Hiraoka

Hirofumi Harazoe

Kenichi Tominari

Eiichi Kato

Shouji Hiraoka

Masaki Kohsaka

Akivoshi Shimizu

A process for preparing polyester pellets which involves blending polyethylene terephthalate and polyethylene isophthalate copolymer before solid state polymerization, the polyethylene isophthalate copolymer being composed of dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, palletizing the blend and crystallizing the pellets.

Process of making polyester pellets

The invention relates to a process for producing an aliphatic polyester excellent in stability which includes subjecting an aliphatic polyester containing at least 50% of an aliphatic hydroxycarboxylic acid unit, obtainable by solid-phase polymerization under a flowing gas in the presence of a volatile catalyst so as to have a desired weight average molecular weight within the range of 50,000 to 1,000,000, to a heat treatment at a temperature equal to or higher than the reaction temperature of the solid-phase polymerization under a flowing gas with maintaining the aliphatic polyester in a solid state. According to the process of the invention, an aliphatic polyester excellent in stability at molding and storage stability is obtained.

Process for producing aliphatic polyester excellent in stability

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

A process for preparing a polyhydroxycarboxylic acid having a weight average molecular weight of 50,000 to 1,000,000, which comprises a crystallizing step comprising (A) a step of heating pellets of a polyhydroxycarboxylic acid having a weight average molecular weight of 2,000 to 100,000 under stirring to a temperature from glass transition point or higher to a melting point or lower and heating until a defined result is attained, and (B) a step of heating the polyhydroxycarboxylic acid to a temperature of solid phase polycondensation reaction temperature, and a solid phase polycondensation reaction step of reacting the crystallized polyhydroxycarboxylic acid at an endothermic start temperature or lower of an endothermic peak as recognized upon temperature elevation analysis of the crystallized polyhydroxycarboxylic acid by using a differential scanning calorimeter.

Process for preparing polyhydroxycarboxylic acid

A process for producing aliphatic polyester wherein a crystallized aliphatic polyester prepolymer formed from an aliphatic dihydric alcohol and an aliphatic dicarboxylic acid and having a weight-average molecular weight of 2,000 to 100,000 is caused to undergo solid-phase polymerization in the presence of a volatile catalyst to make an aliphatic polyester having a weight-average molecular weight of 50,000 to 1,000,000. This process is more efficient than any prior process calling for a complicated step for catalyst removal, since it enables the removal of the catalyst from the reaction system during and/or after solid-phase polymerization. The polyester is comparable in stability to any aliphatic polyester having any catalyst removed therefrom.

Process for preparing aliphatic 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.

Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5% by mol and constituent units derived from isophthalic acid are 0.5 to 85% by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5% by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75% by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (&deg;C.)), as measured by a differential scanning calorimeter, satisfies the formula &lsqb;1/527&minus;0.0017&middot;ln(1&minus;(m,&plus;m,)/200)&rsqb;,&minus;273<Tm&lE;265; said polyester pellets having a density of not less than 1,350 kg/m,. Also disclosed is a process for preparing the polyester pellets. The polyester pellets are excellent in gas barrier properties, transparency and heat resistance and hardly generate acetaldehyde.

Polyester pellets

The invention provides a process for producing high-molecular aliphatic polyesters capable of being substitutes for general-purpose resins that are required to have high toughness, in a simplified manner and at a high volume efficiency. Specifically, in the process, used as the starting material is an easily-available, low-molecular aliphatic polyester prepolymer to be prepared through polycondensation of inexpensive materials of an aliphatic hydroxycarboxylic acid such as lactic acid, glycolic acid or the like, an aliphatic polyalcohol such as butanediol or the like, and an aliphatic polycarboxylic acid such as succinic acid or the like, and the starting prepolymer is crystallized and thereafter polycondensed in a solid phase in the presence of a catalyst to give the intended, tough and high-molecular aliphatic polyester.

Preparation process of polyester

The invention provides a process for preparing a polyester comprising a liquid phase polycondensation step in which a dicarboxylic acid including terephthalic acid or its ester derivative and a diol including ethylene glycol or its ester derivative are subjected to polycondensation reaction in liquid phase and molten state under heating in the presence of a polycondensation catalyst to produce a polyester (a) having an intrinsic viscosity, as measured in o-chlorophenol, of 0.7 to 1.5 dl/g; a hot water treatment step in which the polyester (a) is contacted with hot water of 60.degree. to 130.degree. C. for 30 minutes to 10 hours; a drying step in which the polyester after the hot water treatment step is dried at a temperature of 110.degree. to 150.degree. C. for 30 minutes to 6 hours; and a heat treatment step in which the polyester after the drying treatment step is heated at a temperature of 160.degree. to 200.degree. C. for 1 to 10 hours; wherein the finally obtained polyester has an acetaldehyde content of not more than 10 ppm. The polyester (a) obtained in the step can be precrystallized in a precrystallization step by keeping it in an atmosphere of a heat-up crystallization temperature (T.sub.c1) to 200.degree. C. for 1 minute to 4 hours, prior to the drying step and the heat treatment step. Further, when the precrystallization step is carried out, the polyester obtained in the step can also be subjected to the heat treatment step and then the hot water treatment step. The process of the invention has advantages that a solid phase polycondensation step can be omitted, and the process can provide a polyester having a low acetaldehyde content as well as reduced tendency to increase acetaldehyde during the molding process. Thus the polyester obtained by the process of the invention is particularly suited as a material for preform and beverage bottles formed from the preform. These bottles do not alter the tastes of the contents therein.

Process for preparing polyester

A packaging laminate material comprises a paper substrate and a polyester resin layer provided on at least the innermost surface side of the substrate, wherein the polyester resin comprises dicarboxylic acid units comprising terephthalic acid and adipic acid and dihydroxy compound units comprising ethylene glycol and a second different dihydroxy compound. The polyester may also contain polyfunctional units derived from a polycarboxylic acid having a valence of 3 or more and/or derived from a polyglycol having a valence of 3 or more. The packaging laminate has a high heat-sealing strength, a small decrease in the heat-sealing strength even after the laminate is subjected to a hot water treatment or a hot hydrogen peroxide treatment, and is excellent in scent (odor) retention properties.

Packaging laminate material

According to the present invention, a process which comprises bringing polyethylene terephthalate having an intrinsic viscosity of at least 0.50 dl/g and a density of 1.38 g/cm.sup.3 or more into contact with water is provided. In the water-treated polyethylene terephthalate obtained in the present invention, amounts of oligomers and acetaldehyde formed at the time of molding said polyethylene terephthalate into molded articles are small, and the contamination of the mold therewith is difficult to occur and further the contents of said molded articles does not change in flavor and fragrance.

Process for treatment of polyethylene terephthalate, polyethylene

According to the present invention, a process which comprises bringing polyethylene terephthalate having an intrinsic viscosity of at least 0.50 dl/g and a density of 1.38 g/cm.sup.3 or more into contact with water is provided. In the water-treated polyethylene terephthalate obtained in the present invention, amounts of oligomers and acetaldehyde formed at the time of molding said polyethylene terephthalate into molded articles are small, and the contamination of the mold therewith is difficult to occur and further the contents of said molded articles does not change in flavour and fragrance.

Ethylene/C.sub.4 -C.sub.20 alpha-olefin copolymers are disclosed which have new characteristics in regard to composition distribution, degree of branching, randomness and crystallinity by DSC melting points. These copolymers have excellent transparency, impact strength, tear strength, blocking resistance, environmental stress cracking resistance, heat resistance and low-temperature heat sealability in a well-balanced combination when they have a density of at least 0.90. When their density is less than 0.90, these copolymers have particularly excellent transparency, impact strength and low-temperature heat sealability, and by incorporating them in various thermoplastic resins, they serve as an excellent modifier for improved impact strength and low-temperature heat sealability.

Linear ethylene copolymer

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Waki-cho, Japan

Masayuki Sakai