| 摘要 |
PROBLEM TO BE SOLVED: To provide a polymer foam excellent in surface smoothness and uniformity, to provide an electret using the same, and to provide a method for producing the same. SOLUTION: A constituting material containing a substance capable of producing an acid or base with active energy rays and a compound capable of reacting with the acid or base to decomposition-release a low boiling point evaporable substance is foamed to produce a closed cell-having sheet having an average cell diameter of 0.1 to 10μm and a porosity of 10 to 95% and used for electret. The closed cell-having sheet is subjected to the irradiation of electron beams or to corona discharge to charge the insides of the cells, thus forming the electret. COPYRIGHT: (C)2007,JPO&INPIT
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