METHOD OF PRODUCTION OF SEMI-PERMEABLE CELLULOSE ACETATE MEMBRANE Russian patent published in 2007 - IPC B01D67/00 B01D71/16 

FIELD: production of membranes; separation of liquids in microbiological, biochemical and pharmaceutical industries.

SUBSTANCE: proposed method includes preparation of molding solution by dissolving cellulose acetate in mixture of organic solvent, precipitant, water and plasticizer, application of molding solution on moving surface and drying. Molding solution thus prepared is subjected to thermostatting continued for 14-16 h at temperature of 23-26°C. Application of molding solution and molding are performed in confined working space at relative humidity of 15-50% and additional introduction of precipitant and organic solvent mixture into confined molding and evaporating space taken at ratio of (0.3-0.5) : (0.5-1.0) parts by mass in the amount of 1000-6000 mg per m³ of confined working space. During molding, rate of air flow is maintained at level between 0.8 and 0.9 m/s. Ratio of maximum size of pores to their minimum size does not exceed 1.3.

EFFECT: reduced ratio of maximum size of pores to their minimum size.

2 cl, 5 ex