To obtain the subject composition excellent in storage stability, capable of providing a coating film excellent in hardness, water resistance, stain resistance, etc., by compounding an emulsion of a specific graft block copolymer with colloidal silica subjected to specific surface treatment.
This composition comprises (A) an emulsion of a graft block copolymer comprising (i) a polymer block composed of dimethylsiloxane as a repeating unit, (ii) a polymer block composed of a vinyl polymerizable monomer as a repeating unit and (iii) a silicon-containing graft cross-linked unit copolymerized with the components (i) and (ii) and (B) colloidal silica subjected to surface treatment with a silane compound of the formula SiR1n+1(OR2)3-n (R1 is H or a 1-10C hydrocarbon; R2 is H or a 1-10C hydrocarbon which may contain an ether bond; (n) is 0-2) (preferably trimethoxymethylsilane) in the ratio of 1-300 pts.wt. of the solid content of the component B based on 100 pts.wt. of the component A. Preferably, the component (ii) contains an alkoxysilyl group and/or silanol group.
FUJIWARA TADAYUKI
SHIMOI YOKO
