Gas permeable membrane
AssigneeE. I. Du Pont de Nemours and Company
InventorJohn Chu Chen
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Abstract
Disclosed is a blended composition comprising a humidity-dependent composition having a ratio of wet cup permeance to dry cup permeance greater than 10 and a crystallizable polymer sufficiently permeable to oxygen, carbon dioxide and water vapor, 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 10° C. between 0° C. and 40° C. Also disclosed are packaging materials comprising the blended composition and methods for storing respiring materials using the packaging materials.
Claims21
A blended composition comprising or produced from a humidity-dependent composition and a crystallizable polymer wherein
- the humidity-dependent composition has a ratio of wet cup permeance to dry cup permeance greater than 10, measured according to ASTM E 96-00 at a temperature of 23° C.;
- 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 crystallizable polymer has a first order transition point Tm from 0° C. to 40° C. and a heat of fusion of at least 5 J/g and is sufficiently permeable to oxygen, carbon dioxide, and/or water vapor;
- and the polymeric material exhibiting an increase in permeability to at least one of oxygen, carbon dioxide or water vapor by a factor of at least 2.5 over a temperature range of 10° C. between 0° C. and 40° C.
Dependencies are inferred from the claim text.