| 摘要 |
PROBLEM TO BE SOLVED: To improve interlaminar strength by using copolymer composed by graft copolymerizing unsaturated carboxylic acid and/or its anhydride on thermoplastic polymer, and laminating it and a porous layer composed of thermoplastic polymer. SOLUTION: At least one first porous layer composed of copolymer constituted by graft copolymerizing unsaturated carboxylic acid and/or its anhydride on thermoplastic polymer, and at least one second porous layer composed of thermoplastic polymer are laminated and integrated. Acrylic acid, methacrylic acid, or unhydrous maleic acid is preferable for the unsaturated carboxylic acid and/or its anhydride. Polyethylene or polypropylene is most preferable for the first porous layer. The graft ratio should be normally 0.01-10%. The graft copolymerization process is carried out, for example, by irradiating electron radiation, etc. to the thermoplastic polymer, and then heating it in an organic solvent solution composed of the unsaturated carboxylic acid and/or its anhydride. |
