Patent ID: 8057872

Claim:
A multilayer structure comprising or produced from at least two layers wherein The first layer comprises a humidity-dependent composition having a ratio of wet cup permeance to dry cup permeance of at least 10 when measured according to ASTM E 96-00 at a temperature of 23Â° C.; wherein the wet cup permeance is determined at an average relative humidity of 75% and the dry cup permeance is determined at an average relative humidity of 25%; and The second layer comprises a crystallizable polymer having a first order transition point T m from 0Â° C. to 40Â° C. and a heat of fusion of at least 5 J/g, and said crystallizable polymer being sufficiently permeable to oxygen, carbon dioxide and water vapor and the polymeric material exhibiting an increase in permeability to at least one of oxygen and carbon dioxide by a factor of at least 2.5 over a temperature range of 10Â° C. between 0Â° C. and 40Â° C.