Method of making moisture vapor permeable and water resistant rubbery materials

Claim 1

IN THE METHOD OF MAKING A POROUS SHEET MATERIAL COMPRISING DEPOSITING ON A BASE A RELATIVELY THIN LAYER OF A NON-AQUEOUS VULCANIZABLE RUBBER COMPOSITION CONTAINING RUBBER SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER, RUBBERY HOMOPOLYMER OF A DIENE, A RUBBERY COPOLYMER OF AT LEAST ONE DIENE AND AT LEAST ONE COPOLYMERIZABLE MONOMER HAVING A SINGLE CARBON TO CARBON DOUBLE BOND AND SELECTED FROM THE GROUP CONSISTING OF ISOBUTYLENE, STYRENE, METHYL STYRENE, METACHLOROSTYRENE, ACRYLONITRILE, METHACRYLONITRILE, ALPHA CHLOROACRYLONITRILE, METHYL ACRYLATE, ETHYL ACRYLATE, BUTYL ACRYLATE, METHYL METHACRYLATE, ETHYL METHACRYLATE AND 2-VINYL PYRIDINE, A RUBBERY ORGANIC POLYSULIFIDE POLYMER AND A RUBBERY POLYACRYLATE AND MIXTURELS THEREOF, SAID DIENE BEING SELECTED FROM THE GROUP CONSISTING OF OPEN-CHAIN CONJUGATED DIENE HYDROCARBONS AND OPEN-CHAIN CONJUGATED DIENE HYDROCARBONS HAVING ONE ATOM OF HYDROGEN REPLACED WITH CHLORINE AND SAID DIENE HAVING FROM '' TO 8 CARBON ATOMS AND MIXED THEREWITH A FINELY-DIVIDED, SOLID, NON-HYGROSCOPIC MATERIAL SOLUBLE IN A NON-SOLVENT FOR SAID RUBBER COMPOSITON, VULCANIZING SAID LAYER, AND REMOVING SAID FINELY-DIVIDED MATERIAL FROM SAID LAYER BY TREATING SAID LAYER WITH A SOLVENT WHICH IS A SOLVENT FOR SAID FINELYDIVIDED MATERIAL AND WHICH IS A NON-SOLVENT FOR SAID RUBBERY COMPOSITION, THE IMPROVEMENT IN WHICH SAID FINELYDIVIDED MATERIAL IS PRESENT IN SAID COMPOSITION IN AN AMOUNT OF FROM ABOUT 20 TO 90 PARTS BY WEIGHT PER 100 PARTS BY WEIGHT OF SAID RUBBER IN SAID COMPOSITION AND IN WHICH SAID FINELY-DIVIDED MATERIAL HAS A PARTICLE SIZE WHEREIN ESSENTIALLY ALL OF THE PARTICLES OF SAID MATERIAL PASS THROUGH ABOUT A 65 MESH USS SCREEN AND A PREDOMINANT AMOUNT OF SAID PARTICLES PASS THROUGH ABOUT A 100 MESH USS SCREEN TO PRODUCE PORES IN SAID COMPOSITION WHICH PERMIT VAPOR PERMEABILITY AND RESIST THE PASSAGE OF WATER.