| 摘要 |
PURPOSE:To reduce resin eluate and improve mold release characteristics and thickness accuracy by preparing a prepreg which is made from impregnation in phenol resin varnish and drying after a peripheral portion of a substrate is preimpregnated with an aqueous solution of a mixture of a surfactant and a phenol resin curing accelerating agent. CONSTITUTION:For instance, 10mm. widths on both sides of kraft paper of 1,050mm. wide which is continuously supplied and 20mm. widths at an interval of 1,040mm. vertically to the flow of the base paper are preimpregnated. The impregnation solution is an aqueous solution of a surface active agent and a curing accelerating agent of phenol resin, and the impregnation in the flow direction of the substrate is carried out by dripping and that in the vertical direction is performed by touching of a sponge roll. Then, the substrate is continuously soaked in a vat filled with phenol resin varnish and dried by a drying oven, and a continuous prepreg is obtained. Then, the center of the preimpregnated portion of 20mm. wide in the direction vertical to the flow is cut and a prepreg of which 10mm. peripheral width is preimpregnated and other portions are impregnated with phenol resin can be obtained. The concentrations of the surface active agent and the phenol resin cure accelerating agent of the mixed aqueous solution are recommended to be selected respectively within the scope of 5-70wt%. |
