Flame retardant-containing particle, resin composition, fire-extinguishing sheet, and application thereof

Abstract

A flame retardant-containing particle (C) is obtained by polymerizing a monomer (A) in a composition containing: the monomer (A), which contains two or more monomers (A-1) having polymerizable unsaturated double bonds, and a monomer (A-2) having two or more polymerizable unsaturated double bonds; and a phosphorus-based flame retardant (B) dissolved in at least a part of the two or more monomers (A-1). The particle (C) includes a resin layer (D) formed by polymerizing the monomer (A), and the elution rate of the resin layer (D) into an electrolyte is 40 mass% or less.