| 摘要 |
PURPOSE:To enable manufacture of a prepreg sheet containing no bubbles, by a method wherein a woven fabric base material is led to a drying chamber by dipping the same into low-density varnish after dipping of the same into a solvent and led the same to the drying chamber by dipping the same into high-density in succession. CONSTITUTION:Woven fabrics rolled in a roll-like state is pulled out, dipped into a room temperature or warmed solvent and then air in the woven fabrics is replaced with the solvent. Successively, the woven fabrics impregnated with the solvent is dipped into low-density varnish whose viscosity is 0.5 poise or lower, led to a drying chamber by pulling out of the varnish and performs the first time impregnation with the varnish and scattering of the solvent. Successively, the same is dipped into high-density varnish whose viscosity is 0.5-50 poise, dried after a thickness of the same has been squeezed with a pair of rolls and a prepreg sheet of desired resin content is obtained. As the solvent with which original yarn is impregnated is scattered at the first time drying, generation of bubbles within the original yarn due to scattering of the solvent at the second time drying does not happen and a production rate of the prepreg sheet can be increased by raising a drying temperature. |
