Patent ID: 7476712

Claim:
A film which consists essentially of a polyvalent metal salt of a carboxylic acid which is the reaction product of carboxyl groups of a poly(carboxylic acid) polymer (A) with a polyvalent metal compound (B), wherein the poly(carboxylic acid) polymer (A) is a homopolymer of an α,β-monoethylenically unsaturated carboxylic acid or copolymer of at least two types of α,β-monoethylenically unsaturated carboxylic acids or a mixture of at least two such polymers, wherein said α,β-monoethylenically unsaturated carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and crotonic acid, wherein the film exhibits a peak ratio (A 1560 /A 1700 ) of a height A 1560 of an absorption peak at a wave number of 1560 cm −1 to a height A 1700 of an absorption peak at a wave number of 1700 cm −1 as determined by infrared absorption spectrum of the film which is at least 0.25, and wherein the film is soluble in a 1 N aqueous hydrochloric acid solution and/or a 1 N aqueous sodium hydroxide solution at room temperature for 24 hours.