| 摘要 |
<p>To obtain aqueous paints with which paint films which have excellent paint film properties such as water resistance and resistance to chemical attack, and excellent finished appearance can be obtained, and which have excellent painting operability and storage stability. An unsaturated bond-containing acrylic based copolymer (a) obtained by reacting an acrylic based copolymer (a1) of acid value 35-120 mg.KOH/gram, hydroxy group value 50-150 mg.KOH/gram, glass transition temperature -20 - +50 °C and number average molecular weight 4500-9000 and an unsaturated monomer mixture (a2), which has functional groups which can react with hydroxy groups, in a mol ratio of a2/a1 = 0.4-1.5, and a monomer composition (b) compounded in such a way that the acid value is not more than 15 and the hydroxy group value is 50-150 are reacted in the proportions by weight of a/b = 10/90 - 60/40 to produce a water dispersible acrylic based graft copolymer which has an acid value of 10-30, a hydroxy group value of 50-150, a glass transition temperature of -20 - +50 °C and number average molecular weight 10000-100000, in which side chains comprising the aforementioned b are graft polymerized on the main chains comprising the aforementioned a, and this copolymer is dispersed in an aqueous medium and an aqueous paint is obtained.</p> |
