Water-based polyurethane resin composition and coating composition comprising the same

Abstract

A two-pack type composition which comprises a water-based polyurethane resin coating composition, an internal crosslinking agent, and an external crosslinking agent and which gives a coating film having a higher hardness. The composition gives a coating film improved in gloss even when the external crosslinking agent has been diluted with a high-boiling solvent in order to heighten the mixability of the external crosslinking agent with a main-ingredient emulsion. The two-pack type water-based polyurethane resin composition is characterized by comprising: an ingredient (A) which is a water-compatible polyurethane resin obtained by reacting a diisocyanate compound (a) with a fatty acid having an active-hydrogen group (b) and with a polyol compound (c) to obtain a urethane prepolymer, incorporating a polyfunctional polyisocyanate compound and a succinate type sulfonic acid salt into the prepolymer, neutralizing the mixture, and then subject it to a chain extension reaction; and an ingredient (B) which includes a polyfunctional polyisocyanate compound dispersible in the ingredient (A).

Description

technical field [0001] The present invention relates to a water-based polyurethane resin composition and a coating composition as its excellent application, in particular, to a water-based polyurethane resin coating composition and a manufacturing method thereof. A water-based polyurethane resin coating composition that mixes a succinic acid ester sulfonate as a specific emulsifier to improve the hardness and gloss of the coating film cured at room temperature and has excellent storage stability. Background technique [0002] Urethane resin compositions are widely used in coatings, adhesives or printing inks, molding materials for various industrial materials, and the like due to various excellent physical properties, high functionality, and the like. Among them, as a coating agent, especially a polyurethane resin composition as a coating composition is mainly used in coatings for automotive materials and building materials, etc., but in consideration of environmental prote...

AI Technical Summary

Problems solved by technology

However, when using an internally highly cross-linked low-hydroxyl water-based polyurethane resin, for a two-component composition, in order to reduce the viscosity of the polyfunctional polyisocyanate compound, improve the miscibility, and improve the film-forming properties of the composition, dilute it with a high-boiling point solvent. A polyfunctional polyisocyanate compound is dispersed, but at this time, there is a problem that the gloss of the coating film obtained by applying the two-component composition is greatly reduced

[0005] In addition, as a method of improving the glossiness of the coating film of the two-component water-based polyurethane resin coating composition, there is known a method of blending polyol additives such as ethylene glycol and neopentyl glycol into the aqueous polyurethane resin dispersion. (Refer to Patent Document 3); the method of using a water-dispersible polyisocyanate curing agent having a polyether chain containing an ethylene oxide unit (refer to Patent Document 4), etc. The storage stability, etc. cannot be considered satisfactory

Images