摘要 |
A polyethylene resin surface is formed on a surface of a nonwoven fabric, which is made of polypropylene resin as a main component material and structured with bonded pieces of the polypropylene resin. The polyethylene resin surface is then subjected to a hydrophilization treatment, such as a radical reaction treatment or a sulfonation treatment. As a result, a secondary battery separator having a high mechanical strength along with a high hydrophilic nature, and a secondary battery using that secondary battery separator are provided. |