| 摘要 |
PROBLEM TO BE SOLVED: To provide a separator that has high tightness with an electrode plate and hardly causes a collapsing phenomenon even after repetitive use by sticking fine rubber particles to a nonwoven fabric. SOLUTION: Nitrile rubber, chloroprene rubber or chlorosulfonated polyethylene each of which is high in heat resistance and acid resistance and has appropriate hardness is preferable for fine rubber particles. It is preferable that the particle diameter of the fine rubber particles be 10μm or less, and their adhesion ratio is 0.1-10 wt.%. A nonwoven fabric formed from a glass fiber is suitable. A separator which includes the glass fiber as a main constituent and into which an extremely fine organic fiber such as polyethylene or polypropylene is mixed has both durability and flexibility. It is desirable that the content of the glass fiber having a diameter not more than 4μm be 50 wt.% or more and its average length be 25 mm or less. If the surface of the glass fiber is surface treated by a silane coupling agent, the fine rubber particles are combined strongly together, so that the restoring force of the separator is improved. For a method to have the rubber particles stuck there, a method for mixing them together with the fiber in manufacturing the separator is desirable.
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