Abstract: This invention relates to a flame retardant additive which does not become slimy when brought in contact with warm water. The flame retardant additive comprises a first compound composed of a nitrogen-containing heterocycle compound and a phosphate, and this first compound is surface treated with at least one hydrophobic compound comprising an organosilicon compound.

Abstract: A novel coating composition comprising a non-halogen flame retardant for use with car interior materials such as car seats, car mats, and ceiling materials is provided. This coating composition has physical properties comparable to those of the coating agents comprising a conventional halogen flame retardant, and has solved the problems of insufficient heat resistance and warm water resistance associated with the ammonium polyphosphate having its surface treated with a functional group-containing organosilicon resin. A car interior material coated with this coating composition is also provided.