Patent ID: 6534561
Filing Date: 2003-03-18
Classification: A61L,C08K

Abstract:
A continuous film or layer formed from a thermoplastic composition comprising:a thermoplastic polymer or mixture of polymers having a viscosity higher than 5000 poise at a temperature of 20Â° C. above the DSC melting point of said polymer or mixture of said polymers and at a frequency of 1 rad/sec, said thermoplastic polymers selected from the group consisting of polyurethanes, poly-ether-amides block copolymers, polyethylene-acrylic acid copolymers, polyethylene oxide and its copolymers, poly lactide and copolymers, polyamides, polyester block copolymers, sulfonated polyesters, poly-ether-ester block copolymers, poly-ether-ester-amide block copolymers, polyacrylates, polyacrylic acids, ionomers, polyethylene-vinyl acetate with a vinyl acetate content of more than 28 weight %, polyvinyl alcohol and its copolymers, polyvinyl ethers and their copolymers, poly-2-ethyl-oxazoline, polyvinyl pyrrolidone and its copolymers, and mixtures thereof, a suitable compatible hydrophilic plasticiser or blend of hydrophilic plasticisers, wherein said thermoplastic composition has a viscosity of from 50 poise to 4000 poise at a frequency of 1 rad/s at a temperature of 210Â° C. or less and a viscosity of less than 2000 poise at a frequency of 1000 rad/s at a temperature of 210Â° C. or less, wherein said compatible hydrophilic plasticisers are selected from the group consisting of acids, esters, amides, alcohols, polyalcohols, and mixtures thereof, and wherein said continuous film or layer is liquid impervious and has a water vapour transmission rate of at least 300 g/m2Â·24h, said water vapour transmission rate measured at 23Â° C. according to the ASTM E-96 â€œUpright Cupâ€  method.