The Nippon Synthetic Chemical Industry Co., Ltd.

Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha

Mitsubishi Chemical Corporation

Yoshiharu Nagao

Atsushi Ono

Akio Harao

Kouji Yamada

Kenji Ninomiya

Yasufumi Beniya

Keisuke Fujimura

Shuuichi Fukuyama

Hiroshi Takida

Naoki Yamada

Shinji Okamoto

Shinichi Tanaka

Tomonori Yoshida

Shinta Miyazumi

Seiichi Honda

Kenji Kato

Minoru Fujita

Masahiko Taniguchi

Youichi Neki

The invention provides a saponified ethylene-vinyl ester copolymer pellet which can be inhibited from cracking, chipping and generation of fine powder at the time of transport and is excellent in melt moldability. The saponified ethylene-vinyl ester copolymer pellet of the invention is a pellet which is obtained from a resin composition containing a saponified ethylene-vinyl ester copolymer resin and in which an amount of fine powder after an impact crushing test with ball mill is 400 ppm or less with respect to the saponified ethylene-vinyl ester copolymer pellet.

Saponified ethylene-vinyl ester copolymer pellet and method for producing saponified ethylene-vinyl ester copolymer pellet

The present invention provides a saponified ethylene-vinyl ester copolymer product from which a film having reduced fish eyes can be obtained and a method for producing an ethylene-vinyl ester copolymer that is a precursor thereof. At the time of producing the ethylene-vinyl ester copolymer, as a vinyl ester monomer, the oxygen concentration at storage and/or transportation is adjusted to from 2 to 8 ppm and the oxygen concentration at polymerization is adjusted to less than 2 ppm.

Method for producing ethylene-vinyl ester copolymer, and saponified ethylene-vinyl ester copolymer product

An ethylene-vinyl alcohol copolymer alcohol solution comprising an ethylene-vinyl alcohol copolymer and an alcohol having a carbon number of not greater than 4 is brought into contact with an aqueous solution of at least one additive selected from a carboxylic compound, a boron compound and a phosphoric compound to replace a part or all of the alcohol with water, whereby an ethylene-vinyl alcohol copolymer composition containing the additive is prepared. This preparation process makes it possible to efficiently replace the alcohol in the ethylene-vinyl alcohol copolymer alcohol solution with water, and homogeneously incorporate the thermal stabilizer in the composition.

Process for preparing ethylene-vinyl alcohol copolymer composition, and process for producing ethylene-vinyl alcohol copolymer pellets

An ethylene-vinyl alcohol copolymer (EVOH) composition preparation process is provided, which comprises the steps of: feeding an EVOH alcohol solution into a tower type apparatus, the EVOH alcohol solution comprising 100 parts by weight of an EVOH and not less than 300 parts by weight of an alcohol having a carbon number of not greater than 4; bringing the EVOH alcohol solution into contact with water, and feeding out a part of the alcohol together with water from the apparatus to provide an EVOH water/alcohol mixture solution comprising 100 parts by weight of the EVOH, 10 to 200 parts by weight of the alcohol and 50 to 200 parts by weight of water; bringing the EVOH water/alcohol mixture solution into contact with water in an agitator container with stirring, and feeding out a part or all of the alcohol together with water from the container to provide an EVOH composition comprising 100 parts by weight of the EVOH, less than 10 parts by weight of the alcohol and 20 to 100 parts by weight of water. This preparation process makes it possible to efficiently replace the alcohol in the EVOH alcohol solution with water to provide a lower water content EVOH composition.

Method of manufacturing ethylene-vinyl acetate copolymer

The method of treating a saponified ethylene vinyl acetate copolymer (A) with an acid (B) and/or its salt (C) which comprises feeding a saponified ethylene-vinyl acetate copolymer (A&prime;) in which the acid (B) and/or salt (C) has been incorporated in advance to a column reactor from its top, simultaneously feeding an aqueous solution of the acid (B) and/or salt (C) from the bottom of the reactor to thereby effect a countercurrent contact of (A&prime;) with the aqueous solution of (B) and/or (C), withdrawing the excess of the aqueous solution of acid (B) and/or salt (C) from the reactor top, and continuously withdrawing the treated saponified ethylene-vinyl acetate copolymer from the reactor bottom.

Method for continuous treatment of saponified ethylene-vinyl acetate copolymer

The invention provides a process for producing a saponified vinyl acetate polymer (a saponified ethylene-vinyl acetate copolymer in particular) which features a minimum of coloration of molding pellets, a well-inhibited emanation of an odor in melt-molding, a high transparency of the product film and a low incidence of fish-eyes in the film, and a process for producing a vinyl acetate polymer (particularly an ethylene-vinyl acetate copolymer) for use as the starting material for said saponified vinyl acetate polymer having said favorable properties. In accordance with the invention, either vinyl acetate alone or vinyl acetate and one or more other monomers are polymerized in the presence of a hydroxylactone compound and a polymerization catalyst. The resulting vinyl acetate polymer (particularly the ethylene-vinyl acetate copolymer) is then saponified.

Method of producing a vinyl acetate polymer and its saponification product

This invention relates to a halogen-containing thermoplastic resin composition comprising 100 parts by weight of a halogen-containing termoplastic resin (A) and 1 to 100 parts by weight of a graft polymer (B) having a melt index of 1 to 15 g/10 min as determined at a temperature of 190.degree. C. under a load of 2.16 kg and a benzene-insoluble fraction content of not more than 30 percent by weight as obtainable by graft-polymerizing 100 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 50 to 90 percent by weight as a substrate with 5 to 50 parts by weight of at least one monomer which, when polymerized alone, gives a homopolymer with a glass transition temperature of 65.degree. to 150.degree. C. (b2). This resin composition has markedly improved long-run moldability.

Halogen-containing thermoplastic resin composition

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Osaka, Japan

Yoshiharu Nagao