The Nippon Synthetic Chemical Industry Co., Ltd.

Keisuke Fujimura

Yasufumi Beniya

Akio Harao

Yoshiharu Nagao

Shinji Okamoto

Satoshi Matsunuma

Nobuaki Sato

Osamu Hommura

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

A method of producing a vinyl alcohol resin having a water content of not higher than 10 wt % by performing a multistage dewatering process by means of a kneading machine. The method permits efficient dewatering of a highly hydrous vinyl alcohol resin to ensure easy production of a lower water content vinyl alcohol resin having a water content of not higher than 10 wt %, thereby reducing production costs.

Method for producing vinyl alcohol resin

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.

A process is provided for producing an ethylene/vinyl alcohol copolymer by which impurities such as catalyst residue and by-products and solvent are removed to a high degree. A high-quality, homogeneous product can be efficiently produced by including a washing step including: introducing a paste containing an ethylene/vinyl alcohol copolymer and an alcohol into a washing tank; applying a shear force to the paste to knead the paste while contacting the paste with washing water so that a surface of the paste is repeatedly displaced by an inner part thereof; and discharging the alcohol to an outside of the tank together with the washing water to obtain a water-containing ethylene/vinyl alcohol copolymer composition having a small alcohol content.

Process for producing ethylene/vinyl alcohol copolymer

Processes for manufacturing a composition of a solvolysis product of an ethylene-vinyl ester copolymer, which comprises: conducting solvolysis of an ethylene-vinyl ester copolymer (A') and a modified ethylene-vinyl ester copolymer (B&#x2032;) comprising a unit derived from a compound represented by the general formula (2) in one system to manufacture the composition of a solvolysis product of an ethylene-vinyl ester copolymer comprising a solvolysis product (A) of the ethylene-vinyl ester copolymer and a solvolysis product (B) of the modified ethylene-vinyl ester copolymer comprising a unit represented by the general formula (1), wherein a ratio of an ethylene content (B&#x2032;)/(A&#x2032;) of copolymer (A&#x2032;) and copolymer (B&#x2032;) in conducting solvolysis is 1 or more, and a blending ratio (B&#x2032;)/(A&#x2032;) of the ethylene-vinyl ester copolymer (A&#x2032;) and the modified ethylene-vinyl ester copolymer (B&#x2032;) is from 50/50 to 1/99 by weight: 

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Osaka, Japan

Keisuke Fujimura