Nippon Polyurethane Industry Co., Ltd.

Iku Ohki

Naotaka Izumi

Mitsushige Ikemoto

Takeshi Morishima

Takaki Jono

Mitsuru Chiba

A aqueous modified polyisocyanate intended to be dispersed in an aqueous medium for use and obtained by reacting an HDI derivative with (A) a modifying agent composed of a methoxy polyoxyalkylene glycol mainly comprising an ethylene oxide unit, (B) a modifying agent composed of a hydroxyl group-terminated polyoxyalkylene glycol produced by using an alcohol having 8 or more carbon atoms as an initiator and mainly comprising a propylene oxide unit, and (C) a modifying agent composed of an ester compound having at least one hydroxyl group with an alkali metal salt of sulfonic acid introduced therein, wherein the concentration (calculated value) of the alkali metal salt of sulfonic acid derived from the modifying agent (C) is 1.5 to 25 &#x3bc;mol/g. The aqueous modified polyisocyanate is not only excellent in dispersion stability in water but also excellent in stability of the isocyanate group in water even under temperature conditions of 35 &#xb0; C. or higher.

Aqueous modified polyisocyanate, non-yellowing coating composition, and adhesive composition

[PROBLEMS] The invention is to provide an aqueous one-component coating agent that is environmentally friendly and safe, and is excellent in productivity and storage stability, and also in alkali resistance and solvent resistance of a coated film. [MEANS FOR SOLVING PROBLEMS] The problems are solved by providing a method for producing polyurethane emulsion for an aqueous one-component coating agent, comprising: reacting an organic diisocyanate (a1), a high molecular weight polyol (a2) and a low molecular weight glycol containing a carboxyl group (a3) to produce an isocyanate-terminated urethane prepolymer having a carboxyl group (A); mixing the urethane prepolymer (A) with a polyisocyanate containing a nonionic polar group (B); neutralizing the carboxyl group in the system with a neutralizing agent (C); and subjecting the mixture to emulsification in water and chain extension with water or an amine.

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Yokohama, Japan

Iku Ohki