MULTI-PATH STRUCTURES THAT ARE PERMEABLE TO VAPOR OF MOISTURE AND WATERPROOF TO LIQUIDS WITH GREATER PERMEABILITY TO VAPOR OF HUMIDITY AND DIMENSIONAL STABILITY AND ARTICLES THAT INCLUDE SUCH STRUCTURES.

摘要

A multi-layer moisture vapor permeable, liquid impermeable structure comprising at least a first moisture vapor permeable layer, liquid impervious and at least a second moisture vapor permeable layer, liquid impermeable , said second layer comprising: a thermoplastic polymer or mixture of polymers selected from the group consisting of polyurethanes, poly-ether amide block copolymers, polyethylene-acrylic acid copolymers, poly (ethylene oxide) and their copolymers, polylactide and copolymers, polyamides, polyesters, copolyesters, polyester block copolymers, sulfonated polyesters, polyether ester block copolymers, polyether ester amide block copolymers, polyacrylates, poly (acrylic acid) and derivatives, ionomers , polyethylene-vinyl acetate with a vinyl acetate content of at least 28% by weight, polyvinyl alcohol and its copolymers, polyvinyl ether) and its copolymers, poly-2- ethyl-oxazoline and derivatives, polyvinylpyrrolidone and its copolymers, thermoplastic cellulosic derivatives and mixtures thereof, wherein said second layer further comprises a hydrophilic plasticizer or mixture of suitable compatible hydrophilic plasticizers selected from group consisting of acids, esters, amides, alcohols, polyalcohols or mixtures thereof, characterized in that said first layer has a lower water absorption than the water absorption of said second layer, both water absorptions being measured according to the method of ASTM D 570-81 test.