Patent ID: 7838123

Claim:
An article comprising a structure component and a monolithic film wherein the monolithic film is a variable vapor barrier; the structural component is a wall, ceiling, roof, insulation, or sheathing material; the barrier has a moisture permeance of less than 0.1 perms at less than 50% average humidity and a moisture permeance greater than 10 perms at greater than 60% average humidity; the film is made from a composition and has a ratio of wet cup permeance to dry cup permeance greater than 100, measured according to ASTM E 96-00 at a temperature of 73° F. (23° C.); wet cup permeance is determined at an average relative humidity of 75% and dry cup permeance is determined at an average relative humidity of 25%; the composition consists essentially of or is produced from one or more E/X/Y copolymers and one or more organic acids having fewer than 36 carbon atoms, or salts thereof; E is derived from ethylene, X is present in about 2 to about 35 weight % of the copolymer and is derived from at least one C 3 to C 8 α,β-ethylenically unsaturated carboxylic acid, and Y is present in 0 to about 35 weight % of the copolymer and is derived from a softening comonomer, or ionomers of the E/X/Y copolymers; the organic acid or salt thereof is present in the composition from about 1 to about 50 weight % of the composition and the organic acid is optionally substituted with from one to three substituents independently selected from the group consisting of C 1 -C 8 alkyl group, OH group, and OR 1 group; each R 1 is independently C 1 -C 8 alkyl group, C 1 -C 6 alkoxyalkyl group, or COR 2 group; each R 2 is independently H or C 1 -C 8 alkyl group; and greater than 70% acidic groups in the E/X/Y copolymer and the organic acid are nominally neutralized with metal ions; and the metal ions comprise at least 50 mole % sodium ions and the balance of the metal ions are other alkali metal ions.