NONWOVEN FABRIC FOR BATTERY SEPARATOR AND ITS MANUFACTURE

摘要

PURPOSE:To prevent penetration of grains and obtain a separator having a high liquid holding property and tensile strength by processing nonwoven fabric of an average diameter of less than 5mu produced by melt prone method through heat rolls to let it have a tight structure only for its surface part. CONSTITUTION:Material having insulation property and resistance to electrolyte such as polypropylene is injected from a melt prone nozzle 3 to be put on a net conveyor 4 to form nonwoven fabric 5 of an average diameter of less than 5mu. The nonwoven fabric formed by melt prone method is easy to apply shrinkage work by a thermal process to it. The nonwoven fabric 5 is heat-processed by means of heat rollers 6. Surface distance between the rollers 6 shall be narrower than 30% final thickness of the nonwoven fabric, and the void rate at the surface part of the nonwoven fabric shall be less than 70%, while the apparent void rate for the whole shall be 70-91%. The tensile strength of the nonwoven fabric shall be 1.5kg/2.5cm or over.