Moisture vapor permeable sheet materials

摘要

A moisture vapor permeable sheet material is comprised of a homogeneous admixture of a synthetic polymer material and a protein derivative. The sheet material is moisture vapor permeable and nonpenetrable by liquid water. The sheet material additionally can have coated thereon a pressure sensitive adhesive which is comprised of a synthetic organic polymer adhesive and a soluble protein derivative in solid solution. Sheet material is formed by providing a homogeneous fluid solution of a soluble protein derivative and a synthetic organic polymer in a solvent. The protein derivative has a pH level compatible with the pH level of the organic polymer. Film is formed from the homogeneous fluid solution and the solvent is removed from the film to form the sheet material which is moisture vapor permeable. When the sheet material includes an adhesive, the adhesive is coated as a fluid solution in a solvent on one side of the sheet material.