PRODUCTION OF POROUS MEMBRANE

• Main Authors: ITO HIDEAKI, KAKIHARA HAJIME
• Format: Patent
• Language: English
• Published: 26.03.1999
• Edition: 6
• Subjects: ADHESIVES; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; CORRECTING FLUIDS; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; DYES; FILLING PASTES; GENERAL PROCESSES OF COMPOUNDING; HUMAN NECESSITIES; HYGIENE; INKS; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MEDICAL OR VETERINARY SCIENCE; METALLURGY; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; POLISHES; THEIR PREPARATION OR CHEMICAL WORKING-UP; USE OF MATERIALS THEREFOR; WOODSTAINS; WORKING-UP

PROBLEM TO BE SOLVED: To obtain a membrane having good through-pores by applying an emulsion comprising a lowly water-soluble membraneforming polymeric material, a lowly water-miscible organic solvent having a boiling point lower than that of water and water to a support, evaporating the organic solvent by drying, releasing the obtained membrane from the support and removing the surface layer by dissolution in an acid or an alkali. SOLUTION: An emulsion prepared by mixing a lowly water-soluble membrane-forming polymeric material such as a polylactate with a lowly water- miscible organic solvent being capable of dissolving the polymeric material and having a boiling point lower than that of water (e.g. chloroform) and water is applied to a support such as made of teflon. The organic solvent is first evaporated from the wet film, and the water is evaporated from it to bring the film into the state in which the sites where water particles have been present are vacant. Then, the membrane is heated to 120-150 deg.C, and the membrane having many pores are released from the support, and the surface layer on the side having been in contact with the support is removed by dissolution in an acid or an alkali aqueous solution to obtain a polymer membrane having good air permeability.