Vinyl ester resin composition that contains minute polymer particles, process for production of same, and cured products of same

1. A method for producing a minute polymer particle-containing vinyl ester resin composition,

the minute polymer particle-containing vinyl ester resin composition comprising a vinyl ester resin, 1 to 100 parts by weight of minute polymer particles based on 100 parts by weight of the vinyl ester resin, and 0 to 100 parts by weight of a vinyl monomer based on 100 parts by weight of the vinyl ester resin, wherein

the minute polymer particles comprise primary particles having a size of 0.05 μm to 1 μm, and

the minute polymer particles are dispersed in the minute polymer particle-containing vinyl ester resin composition, and

the method comprising in the following order:

obtaining a loose agglomerate of minute polymer particles;

obtaining a minute polymer particle dispersion;

obtaining a minute polymer particle-containing polyepoxide;

obtaining a minute polymer particle-containing vinyl ester resin by reacting an ethylenically unsaturated double bond-containing monocarboxylic acid with the minute polymer particle-containing polyepoxide; and

adding the vinyl monomer to the vinyl ester resin.

2. A minute polymer particle-containing vinyl ester resin composition, comprising a vinyl ester resin, 1 to 100 parts by weight of minute polymer particles based on 100 parts by weight of the vinyl ester resin, and 0 to 100 parts by weight of a vinyl monomer based on 100 parts by weight of the vinyl ester resin, wherein

the minute polymer particles comprise primary particles having a size of 0.05 μm to 1 μm,

the minute polymer particles are dispersed in the minute polymer particle-containing vinyl ester resin composition,

the minute polymer particles have a core-shell structure, a shell polymer thereof having a glass transition temperature (Tg) of below 20° C., and

the shell polymer comprises a copolymer of shell forming monomers (B) comprising

5% to 95% by weight of an alkoxyalkyl (meth)acrylate,

0% to 40% by weight of glycidyl (meth)acrylate,

0% to 20% by weight of a polyfunctional vinyl monomer, and

5% to 70% by weight of other vinyl monomers,

each based on 100% by weight of the shell forming monomers (B).

3. The minute polymer particle-containing vinyl ester resin composition according to claim 2 , wherein

the vinyl ester resin is a reaction product of an ethylenically unsaturated double bond-containing monocarboxylic acid and a minute polymer particle-containing polyepoxide which contains 100 parts by weight of a polyepoxide and 1 to 100 parts by weight of the minute polymer particles and in which the minute polymer particles comprise primary particles and are dispersed in the polyepoxide.

4. The minute polymer particle-containing vinyl ester resin composition according to claim 2 , wherein

a (meth)acrylate group is grafted to the minute polymer particles.

5. The minute polymer particle-containing vinyl ester resin composition according to claim 3 , wherein

the reaction product is a reaction product of an ethylenically unsaturated double bond-containing monocarboxylic acid and the minute polymer particle-containing polyepoxide in which the epoxy equivalent weight has been increased by 25 g/eq or more from less than 500 g/eq in the presence of the dispersed minute polymer particles.

6. A cured product, obtained by curing by radical polymerization a curable composition comprising the minute polymer particle-containing vinyl ester resin composition according to claim 2 , wherein

the minute polymer particles are dispersed in the cured product.