PURPOSE: To impart rubber elasticity to a coating film to thereby improve its scratch resistance and its resistance to yellowing due to a curative without detriment to its acid resistance by incorporating particles of a vinyl polymer having specific sructural units into the coating film.
CONSTITUTION: A vinyl monomer is polymerized in a lowly polar org. solvent such as an aliph. or arom. hydrocarbon to form a dispersion stabilizer. In the resulting soln. is polymerized a monomer or a group of monomers represented by formula I (wherein R1 to R5 are each H or methyl; m is 0-2; n is 0--10; p is 0 or 1; q is 0-3; and r is 0-3), giving the objective improver which is a nonaq. polymer dispersion comprising 40-90wt.% org. solvent, 10-50wt.% particles of a vinyl polymer having structural units of which at least 30wt.% are units represented by formula II (wherein R1 to R5, m, n, p, q, and r are each the same as in formula I), and 5-40wt.% dispersion stabilizer which is sol. in the solvent and stabilizes the dispersion of the particles. The improver is compounded with other necessary ingredients to give a coating material.
MONMA YASUHIRO
SUGIHARA YASUSHI
