HYDROPHILIC POLYOLEFIN-BASED POLYMERIC POROUS MATERIAL, ITS PRODUCTION AND APPLICATION THEREOF TO BATTERY SEPARATOR

PROBLEM TO BE SOLVED: To produce the subject porous material, having sufficient hydrophilicity and durability in alkalis and useful for battery separators, etc., by bringing a polymeric porous material into contact with a fluorine gas-containing gas, reacting the porous material therewith and then carrying out the dipping treatment of the resultant material in a hot aqueous solution of an alkali. SOLUTION: This hydrophilic polyolefin-based polymeric porous material is produced by bringing a polyolefin-based polymeric porous material, preferably a nonwoven polyolefin fabric into contact with a fluorine gas-containing gas, reacting the porous material therewith, subsequently carrying out the dipping and treatment of the resultant polyolefin-based polymeric porous material in a hot aqueous solution of an alkali, e. g. an aqueous solution of potassium hydroxide at 50-120 deg.C for >=30min. For example, a mixed gas containing oxygen gas, and concretely comprising 1.3vol.% fluorine gas, 86.8vol.% oxygen gas and 11.9vol.% nitrogen gas is preferably used, and the polyolefin-based polymeric porous material is preferably brought into contact with the mixed gas at 0-80 deg.C for a time within the range of 5 sec to 1hr.