| 摘要 |
PROBLEM TO BE SOLVED: To obtain a prepreg which is useful for laminated sheets for electric applications by preparing the prepreg using a fibrous base material and a thermosetting resin varnish, placing the prepreg between releasing films and smoothening the surfaces with heat and pressure. SOLUTION: A fibrous base material, for example, glass fiber-woven cloth, nonwoven fabric, pulp paper and the like is impregnated with (A) a thermosetting resin varnish, and the thermosetting resin in the component A, for example, a phenolic resin, an unsaturated polyester resin, an epoxy resin, or an imide resin, is cured till the stage B (B) to be the main body of prepreg. The main body (B) is placed between a couple of releasing films and press-heated with rollers, then peeled off from the releasing sheets. For example, glass cloth is impregnated with an epoxy resin and cured till the B-stage and the prepreg is put between a couple of releasing film prepared by impregnating glass cloth with a fluororesin and hot-pressing them through hot-pressing rollers, then releasing the films after cooling to give the objective prepreg. |
