MICROPOROUS POLYOLEFIN MEMBRANE, METHOD OF ITS PRODUCTION, STORAGE BATTERY SEPARATOR AND STORAGE BATTERY

摘要

FIELD: process engineering. ^ SUBSTANCE: invention relates to production of microporous polyolefin membranes to be used in storage battery separators. Membrane comprises polyethylene resin and features (a) trip temperature of 135C or lower whereat air permeability on heating at 5C/min rate reaches 1ù105 s/100 cm3, (b) maximum shrinkage at 40%-smelting or less in crosswise direction at 135-145C that is determined thermo mechanically at load of 2 gf at temperature increase rate of 5C/min and (c) melting point of 150C or higher whereat air permeability measured at subsequent heating after reaching trip temperature becomes, again, equal to 1ù105 s/100 cm3 Membrane is produced by mixing polyethylene resin melt with membrane-forming solvent in two-screw extruder in extruding produced solution through die. Cooling is performed to produce gel sheet. Said sheet is stretched at 1-80%/s-rate to provide 100%-length before stretching, and solvent is removed from sheet. ^ EFFECT: better trip melting properties of proposed membrane. ^ 4 cl, 6 dwg, 1 tbl, 9 ex