| 摘要 |
PURPOSE:To obtain a separator with excellent resistances to alkali and to acid which almost completely blocks the penetration of electrode-composing materials, by subjecting a graft-copolymer of a thermoplastics film and a vinyl monomer to cross- linking. CONSTITUTION:The separator of a battery is prepared from a cross-linked graft- copolymer which is made from a thermoplastic film such as a polyethylene film, and a vinyl monomer such as acrylic acid or methacrylic acid. For instance, polyethylene pellets are formed into a film of 25mu thickness, which is subjected to an irradiation of 20 megarad in the air under an electronic ray of 2 million V, 20mA. The film is immersed in a methanol solution containing 30% of methacrylic acid, before the film is immersed in a boiling water to remove the homopolymer of methacrylic acid, thus obtaining a grafted film with the grafted rate of 72%. The thus obtained grafted film is again immersed in a methanol solution containing an epoxy resin and triethylenediamine at 60 deg.C, thereby obtaining a cross-linked grafted-film. |
