Resin composition for high water resistance sheet molding compound, high water resistance sheet molding compound, and high water resistance bathtub

The invention discloses a resin composition for a high water resistance sheet molding compound, a high water resistance sheet molding compound, and a high water resistance bathtub. The resin composition is prepared by mixing 60-90 parts by weight of an unsaturated polyester resin, 10-40 parts by weight of a low shrink agent, 30-180 parts by weight of an inorganic filler, 20-40 parts by weight of short glass fibers, 1-2 parts by weight of an initiator, 2-10 parts by weight of an internal release agent, 1-10 parts by weight of a surface modification agent, 0.5-2 parts by weight of a thickening agent, 0-1 part by weight of a polymerization inhibitor, and 0-10 parts by weight of styrene, wherein the unsaturated polyester resin is a composition comprising one or a plurality materials selected from an o-phenyl type unsaturated resin, a meta-phenyl type unsaturated resin, an epoxy vinyl ester unsaturated resin and a vinyl resin, the unsaturated resin contains carboxyl groups, and the amount of the carboxyl groups is 0.001-0.002% of the total weight of the resin. The high water resistance bathtub of the present invention has excellent water resistance performance.