Tohcello Co., Ltd.

Mitsui Chemicals, Inc.

Tomoyoshi Hakamata

Akira Nomoto

Osamu Nakamura

Yoshihisa Inoue

Kou Tsurugi

Isao Hara

Yoshihiro Yamamoto

Hiroyoshi Watanabe

Nobuhiro Tanabe

A method for producing a solution containing at least an unsaturated carboxylic acid-modified vinyl alcohol polymer is characterized by reacting a vinyl alcohol polymer and an unsaturated carboxylic acid compound in the presence of an acid catalyst soluble in the reaction system or a solid acid catalyst, and a gas barrier film is obtained by using the same. An example thereof is a method for producing a solution (A) containing an unsaturated carboxylic acid-modified vinyl alcohol polymer (b), the method comprising following two steps of: (1) a reaction step in which the unsaturated carboxylic acid-modified vinyl alcohol polymer (b) is formed by reacting a vinyl alcohol polymer and an unsaturated carboxylic acid compound (a) in the presence of an acid catalyst soluble in the reaction system; and (2) an ion exchange step in which at least the acid catalyst of acidic compounds is removed by an anion exchange resin.

Method for producing unsaturated carboxylic acid-modified vinyl alcohol polymer, and gas barrier film or gas barrier laminate using the same

The gas-barrier film of the present invention basically comprises a polymer of a polyvalent metal salt of an unsaturated carboxylic acid compound which gives an infrared absorption spectrum in which the ratio of the absorbance Aat around 1,700 cmattributable to V C&#x2550;O of the carboxylic acid group to the absorbance A at around 1,520 cmattributable to V C&#x2550;O of the carboxylate ion, A/A, is lower than 0.25, and this gas-barrier film and a gas-barrier layered body having the film can be manufactured by applying a solution of a polyvalent metal salt of an unsaturated carboxylic acid compound having a degree of polymerization lower than 20 to at least one side of a substrate layer and then polymerizing the polyvalent metal salt of the unsaturated carboxylic acid compound.

Gas-barrier film, gas-barrier layered body, and process for producing same

Disclosed is an excellent gas barrier laminate whose gas-barrier property has little dependency on temperature and which hardly causes fracture even when the laminate is stretched. A gas barrier film comprising a polymer (A) of an unsaturated carboxylic acid compound monovalent metal salt (a), wherein the polymer (A) contains a modified vinyl alcohol polymer (B); a gas barrier laminate comprising a base layer and the gas barrier film formed on at least one surface of the base layer; and a method for production of a gas barrier laminate comprising the steps of: coating a solution of an unsaturated carboxylic acid compound monovalent metal salt (a) having a polymerization degree less than 20 on at least one surface of a base layer, wherein the solution contains a modified vinyl alcohol polymer (B); performing the polymerization to form a layer of the polymer (A) of the unsaturated carboxylic acid compound monovalent metal salt (a) containing the modified vinyl alcohol polymer (B).

Gas barrier film, gas barrier laminate and method for manufacturing film or laminate

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Ibaraki, Japan

Tomoyoshi Hakamata