摘要 |
This invention is directed to a process for forming a wettable battery separator comprising a non-woven mat of polyolefin fiber by forming a non-woven mat of polyolefin fiber having a thickness in the range 10 to 40 mils and pore sizes less than 40 microns, contacting the mat with an aqueous solution of a water soluble peroxy compound, e.g. hydrogen peroxide or potassium persulfate at a temperature below 70 DEG C., rinsing the mat in water and thereafter immersing the thus treated mat in an aqueous solution of a hydrophilic vinyl monomer such as acrylic, methacrylic, vinyl sulfonic acid, said solution containing a redox catalyst, e.g. an ion of a transition metal, e.g. ferrous, cerous, cobaltous, or an organic amine, thereby causing a graft polymerization of said hydrophilic vinyl monomer on said polyolefin mat to give a wettable polyolefin battery separator. |