Abstract: It is an object to provide a resin molded product of a luminous colorant, free of weld lines. The product is obtained by molding a mixture of a luminous coloring agent and a resin by the use of a mold engraved with a pattern having a plane face on an internal surface.

Abstract: A granular resin solid (a) that serves as a nucleus, has a particle size of 0.5 to 7 mm, and is composed of a molding thermoplastic resin, a powdered additive component (b), and a fixing resin (c) composed of a thermoplastic resin are stirred and mixed, the fixing resin (c) is melted by the frictional heat during stirring and mixing, the powdered additive component (b) is made to adhere to the surface of the granular resin solid (a) by the melted fixing resin (c), and the system is cooled while being stirred, which solidifies the fixing resin (c), thereby providing a granular additive with excellent dispersibility and a uniform particle size by an extremely simple method and at low cost.