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

FIELD: chemistry.

SUBSTANCE: present invention relates to methods of producing microporous polyolefin membranes used as separators in accumulator batteries and in various filters. The method of producing the membranes comprises the following steps: mixing molten polyolefin and a membrane-forming solvent, extrusion of the obtained melt and cooling the extruded article to a gel form, first biaxial stretching at temperature ranging from crystallisation point of the polyolefin dispersion of +15°C to crystallisation point of the dispersion of +40°C, removing the solvent, second monoaxial stretching of the membrane with removal of the solvent at temperature ranging from crystallisation point of the polyolefin dispersion to crystallisation point of the polyolefin dispersion of +40°C.

EFFECT: obtaining microporous polyolefin membranes having large pore diametre, excellent air-permeability, mechanical strength and compression strength.

6 cl, 1 tbl, 17 ex