Iodine type polarizing film, method of producing the same and polarizer using the same

摘要

An object of the present invention is to provide an iodine type polarizing film of a polyvinyl alcohol film showing improved durability, and a method of producing the polarizing film. There is provided an iodine type polarizing film of a polyvinyl alcohol film in/on which iodine is adsorbed and oriented, wherein the polyvinyl alcohol film contains a saponin. This polarizing film can be produced by a method of producing a polarizing film comprising uniaxially stretching a polyvinyl alcohol film, dyeing the polyvinyl alcohol film in an aqueous solution containing iodine, impregnating the polyvinyl alcohol film after dyeing in an aqueous solution containing boric acid, and washing with water after the impregnation in an aqueous solution containing boric acid, wherein a saponin is dissolved and contained in the aqueous solutions of the above-mentioned iodine dyeing or later steps.