Patent ID: 8906451

Claim:
A method for producing coated water-soluble particles in a manner to form two or more coating layers on surfaces of water-soluble particles, comprising: bringing water-soluble particles into a rolling state in a rotary pan or a tumbler, thereafter supplying a first coating material that comprises a polyol component and an isocyanate component to provide first coating bodies that have coating layers formed of the first coating material that has not been sufficiently cured, while maintaining the rolling state of the water-soluble particles, and thereafter additionally supplying a second coating material to surfaces of the first coating bodies to provide second coating bodies that have coating layers of the second coating material, while maintaining the rolling state of the water-soluble particles, wherein supplying the second coating material starts within a time range represented by T x that satisfies the following relational expression: 0.5≦( T x −T 0 )/( T a −T 0 )≦3.0, wherein T 0 is a time at which, after finishing supplying the first coating material, the first coating bodies begin adhering to each other to form aggregated particles and T a is a time at which the volume of the aggregated particles reaches a maximum.