| 摘要 |
PURPOSE:To obtain a curable resin excellent in curability, capable of providing a cured product of excellent chemical resistance and molding shrinkage, and useful as a coating material, an impregnating material, or the like, by condensing a maleimide compound with formaldehyde in the presence of an acidic catalyst. CONSTITUTION:A maleimide compound of formula I (wherein R is H, a 1-12C alkyl, or a 1-12C alkenyl, and A is a 2-3C alkylene), e.g., a compound of formula II, is condensed with formaldehyde in the presence of an acidic catalyst, e.g., sulfuric acid. It is possible to obtain a high-MW (about 1,500-7,000) polymaleimide which has not been obtained heretofore, i.e. a compound of formula III, wherein R and A are as defined above, and n is about 10-50. While a conventional polymaleimide, for example, one obtained by curing N,N'-4,4'-diphenylmethane bismaleimide with a curing agent comprising a polyamine such as 4,4'- diaminodiphenylmethane shows extremely poor curability as compared with an epoxy resin, it becomes possible to obtain a polymaleimide resin of excellent curability by increasing the MW of the resin.
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