METHOD FOR PRODUCING CELLULOSE ACETATE MEMBRANE Russian patent published in 2023 - IPC B01D71/16 B01D67/00 

FIELD: polymer industry.

SUBSTANCE: production of porous polymer films, and in particular a method for obtaining microfiltration membranes used for filtering, analyzing and purifying various media in microbiological, biochemical, pharmaceutical and other industries. A method for producing a cellulose acetate membrane includes the preparation of a molding solution by dissolving cellulose acetates in a mixture of an organic solvent, a precipitant, water and a plasticizer, filtration, thermostatic control, applying a molding solution to a moving metal band, molding and drying. One type of cellulose acetate should be with a low content of associated acetic acid, ranging from 53 to 56 wt.%, and another type of cellulose acetate should be high in bound acetic acid, ranging from 57 to 62 wt.%, polysorbate Twin-80 is added to the molding solution, the molding solution is thermostated for 6 hours at a temperature in the range of 28-30°C, and the molding is carried out at the degree of substitution of the vapor-air mixture of solvents and precipitants with prepared air in the range of 15-20 zone molding volumes per hour.

EFFECT: reduction of the ratio of the maximum pore size to their minimum size to a value not exceeding 1.1-1.2, obtaining a uniform structure with a narrow pore size distribution, reducing the confluent growth of test strain colonies on the membrane surface when microorganisms are isolated from water.

2 cl, 1 dwg, 1 tbl, 1 ex