To obtain an emulsion which gives a film which contains high concentrations of dyes, is excellent in durability and does not peel off even when subjected to a high temperature treatment by subjecting a monomer composition, an oil-soluble dye and a polymerizable group-containing organic silicon monomer to emulsion polymerization in the presence of a polymerization initiator and a reactive emulsifier having a polymerizable group.

A monomer composition preferably contains 70 wt.% (hereinafter referred to as %) or more of a monomer of formula I. An oil-soluble dye preferably has a solubility in an organic solvent at 20°C of 1% or more, a solubility in water at 20°C of 1% or less and a solubility in water at 100°C of 10% or less. An oil-soluble dye is preferably a salt obtained by reacting an anionic dye and a cationic monomer of formula II or a metal complex of azo-based dye. A polymerization initiator is preferably as oil-soluble azo compound. In the formulae, R1 and R3 are each H or CH3; R2 is 3-6C alkyl; R4 to R6 are each 1-8C alkyl, aralkyl or cycloalkyl with the proviso that the total number of carbons is 8 or more; and X is a halogen.