A method for producing reactive fine particles, includes: admixing at least one latent curing agent selected from the group consisting of a urea derivative, an imidazole, a dicyaniamide (DICY), a mixture of any one or more thereof, and a precursor thereof, in a solvent to form a clear solution; spraying the clear solution onto at least one inorganic inert particle selected from the group consisting of a metal oxide, a mineral filler, a natural filler, and a mixture of any one or more thereof, the at least one inorganic inert particle having a specific surface area in the range of about 10 to about 50 m2/g; and removing the solvent to form reactive fine particles that includes a core of inert material coated by a coating layer that includes the at least one latent curing agent.