Integral reverse osmosis membrane with highly pressed woven fabric support member

Claim 1

IN A PROCESS FOR MANUFACTURING SEMI-PREMEABLE INTERGAL CELLULOSIC FILM MEMBRANES SUITABLE FOR USE IN REVERSE OSMOSIS PROCESS, WHICH PROCESS COMPRISES THE STEPS OF A. CASTING IN THE FORM OF A FILM A CONCENTRATED CELLULOSIC DOPE ONTO AN ELONGATED, PREMEABLE, CASTING AND MEMBRANE SUPPORT FABRIC, B. EXPOSING SAID FILM TO A GASEOUS ATMOSPHERE FOR A SUFFICIENT PERIOD OF TIME DEVELOP AN INCIPIENT ACTIVITE LAYER AT THE SURFACE OF THE RESULTING PARTIALLY EVAPORATED LAYER OF DOPE EXPOSED TO SAID GASEOUS ATMOSPHERE, C. THEREAFTER DIVERTING THE ELONGATED FABRIC ON WHICH IS COATED SAID LAYER OF DOPE INTO WATER TO THEREBY CAUSE SAID PARTIALLY EVAPORATED LAYER OF DOPE TO GEL AND FROM A WET MEMBRANE, AND D. THEREAFTER REMOVING TE RESULTING WET MEMBRANE AND FABRIC FROM SAID BATH AS A SUBSTANTIALLY NONSEPARABLE SEMIPERMABLE LAMINATE, SAID CONCENTRATED DOPE BEING COMPRISED OF A BLEND OF AT LEAST ONE CELLULOSIC FILM-FORMING SELECTED FROM THE GROUP CONSISTING OF SOLUBLE FILM-FORMING CELLULOSE ESTER, ETHERS AND MIXED ESTER ETHERS AND AT LEAST ONE PORE-PRODUCING MATERIAL, SAID BEING DISSOLVED IN A VOLATILE, WATER MISCIBLE SOLVENT PROTION IN WHICH SAID FABRIC IS INSOLUBLE, THE IMPROVEMET THEREIN BEING WHERE THE FABRIC COMPRISES SUBSTANTIALLY UNSIZED WRAP AND FILL STRANDS OF SUBSTANTIALLY CONTINUOUS MULTIFILAMENTS OF FIBER-FORMING CRYSTALLINE ORGANIC THERMOSPLASTIC RESIN, SAID FABRIC BEING HEAT PRESSED TO REDER IT SUBSTANTIALLY COMPLETELY FREE OF INTERSTICES AT TE STRAND INTERSECTION, AND THE SOLVENT CONSISTS ESSENTIALLY OF AN EFFECTIVE AMOUNT OF ACETIC ACID, FORMIC ACID, OR MIXTURE OF ACETIC AND FORMIC ACIDS.