MICROPOROUS POLYOLEFIN MEMBRANES AND METHOD OF THEIR PRODUCTION Russian patent published in 2011 - IPC B01D71/26 B01D67/00 C08J5/22 C08J9/00 B29C55/02 B29D7/01 

FIELD: process engineering.

SUBSTANCE: invention relates to production of microporous polyolefin membranes used as separators in storage batteries and filters. Proposed method comprises the following stages: mixing in melting polyolefin and membrane forming solvent, extruding obtained solution and cooling extrudate to produce gel mould, first two-axis membrane expansion at temperature from polyolefin dispersion crystallisation temperature to dispersion crystallisation temperature of +30°C, thermosetting of expanded gel mould, removal of solvent, second one-axis membrane expansion at temperature of polyolefin dispersion crystallisation to of polyolefin dispersion crystallisation of +40°C.

EFFECT: larger pores, higher air permeability, mechanical strength and compression strength.

4 cl, 1 tbl, 9 ex