Multistage colored polymer particle and skin care formulations comprising same

A method of treating a selected area of skin, comprising:

• providing a skin care formulation;
• wherein the skin care formulation comprises:
• a dermatologically acceptable carrier;
• an optional additive;
• and
• 0.01 to 10 wt %, based on weight of the skin care formulation, of a multistage colored polymer particle, comprising:
• (i) a core, wherein the core comprises, as polymerized units, 20 to 60 wt %, based on weight of the core, of a monoethylenically unsaturated carboxylic acid core monomer;
• and 40 to 80 wt %, based on weight of the core, of a non-ionic ethylenically unsaturated core monomer;
• (ii) an inner shell, wherein the inner shell comprises, as polymerized units, 90 to 99.9 wt %, based on weight of the inner shell, of a non-ionic ethylenically unsaturated inner shell monomer;
• 0.01 to 9.95 wt %, based on weight of the inner shell, a monoethylenically unsaturated carboxylic acid inner shell monomer;
• 0 to 9.99 wt %, based on weight of the inner shell, of an aliphatic inner shell monomer selected from the group consisting of allyl acrylate, allyl methacrylate and mixtures thereof;
• and 0 to 10 wt %, based on weight of the inner shell, of a first polymerizable dye monomer;
• (iii) an outer shell, wherein the outer shell comprises, as polymerized units, 15 to 99.5 wt %, based on weight of the outer shell, of a non-ionic ethylenically unsaturated outer shell monomer;
• 0.1 to 10 wt %, based on weight of the outer shell, of a monoethylenically unsaturated non-carboxylic acid outer shell monomer;
• 0 to 10 wt %, based on weight of the outer shell, of a second polymerizable dye monomer;
• and 0 to 70 wt %, based on weight of the outer shell, of an aliphatic outer shell monomer selected from the group consisting of allyl acrylate, allyl methacrylate and mixtures thereof;
• wherein the core, when dry, contains at least one void;
• wherein the first polymerizable dye monomer and the second polymerizable dye monomer are the same or different;
• and wherein the multistage colored polymer particle comprises, as polymerized units, 0.015 to 8 wt %, based on weight of the multistage colored polymer particle, of the first polymerizable dye monomer and the second polymerizable dye monomer combined;
• and
• applying the skin care formulation to a selected area of skin.