Abstract: The present invention provides polymer particles being capable of stably maintaining a hydrophobic protecting agent for skin and/or hair and a method of treating fibers by the polymer particles. It is polymer particles having a volume average particle diameter of 0.001 to 30 &mgr;m, which comprises an organic high-molecular polymer (a) as the wall membrane and a hydrophobic-protecting agent for skin and/or hair (b) as the core material, or chitosan and a polymer of an organic acid having reactive vinyl group and/or a salt thereof as the membrane wall and the protecting agent (b) as the core material; a fiber-treating agent comprising said polymer particles; fiber having said polymer particles present continuously or discontinuously on the surface thereof; or a fiber-treating method which comprises bringing said polymer particles or said fiber-treating agent into contact with fiber.

Abstract: The present invention provides polymer particles being capable of stably maintaining a hydrophobic protecting agent for skin and/or hair and a method of treating fibers by the polymer particles. It is polymer particles having a volume average particle diameter of 0.001 to 30 &mgr;m, which comprises an organic high-molecular polymer (a) as the wall membrane and a hydrophobic -protecting agent for skin and/or hair (b) as the core material, or chitosan and a polymer of an organic acid having reactive vinyl group and/or a salt thereof as the membrane wall and the protecting agent (b) as the core material; a fiber-treating agent comprising said polymer particles; fiber having said polymer particles present continuously or discontinuously on the surface thereof; or a fiber-treating method which comprises bringing said polymer particles or said fiber-treating agent into contact with fiber.