Coating composition composed of powder re-dispersible in water and containing water-soluble polymer and organosilicon compound as base and production of coating film

PROBLEM TO BE SOLVED: To obtain the subject composition capable of producing hydrophobic coating film excellent in stability and weather resistance and applicable to all kinds of inorganic base material by compounding powder re-dispersible in water and containing water soluble polymer and a specific organic silicon compound as a base. SOLUTION: This coating composition is composed, as a base, of an organosilicon compound containing powder re-dispersible in water and composed of (A) a water-soluble polymer and (B) (i) a low molecular-weight organosilicon compound having a viscosity of ≤5000mm 2 /s at 25°C and (ii) a high molecular-weight organopolysiloxane resin having a viscosity of ≤100,000mm 2 /s at 25°C or solid at normal temperature. A polyvinyl alcohol, which has a degree of saponification of 100-240 and a molecular weight of 15,000-100,000, is preferable as the component A. A compound of formula I [R is a monovalent organic group; R 1 is H or an alkyl; (a)=0-3, (b)=0-4 and (a)+(b)≤4] is preferable as the component (i). A compound consisting of a unit of formula II [R 2 is R; R 3 is R 1 ; (c) and (d) are each 0-3 and (c)+(d)≤3] is preferable as the component (ii). COPYRIGHT: (C)1997,JPO