| 摘要 |
PROBLEM TO BE SOLVED: To obtain a prepreg sheet capable of giving a void-free laminate though the resin has been internally added instead of being infiltrated and excellent in dimensional stability by using a base sheet and a plurality of thermosetting resin powders having specified gelation times as the principal components. SOLUTION: This sheet is mainly composed of a base fiber, desirably, a glass fiber, a thermosetting resin powder (A) (e.g. a resin powder obtained by melt-blending an epoxy resin, a phenol novolac resin, and an accelerator, and grinding the blend) having an adjusted gelation time of 150-500 sec at 150 deg.C, and a thermosetting resin powder (B) (e.g. a resin powder obtained by heat- treating resin powder A at 150 deg.C and re-grinding the product) having an adjusted gelation time of 0-100 sec at 150 deg.C. It is desirable that the ratio of the base fiber to the total of resin powders A and B is 60:40 to 10:90 by weight and that the ratio of powder A to powder B is 20:80 to 80:20 by weight.
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