The Nippon Synthetic Chemical Industry Co., Ltd.

Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha

Akio Harao

Yoshiharu Nagao

Yasufumi Beniya

Keisuke Fujimura

Shinji Okamoto

Kenji Ninomiya

Kenji Kato

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.

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: 

Process for manufacturing composition of solvolysis product of ethylene-vinyl ester 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.

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Osaka, Japan

Akio Harao