| 摘要 |
PURPOSE:To minimize generation and residue of voids, by a method wherein after a decompressed and defoamed synthetic resin is poured into a material to be impregnated under reduced pressure, the pressure is raised back to a normal pressure, and after decompressed again, it is raised back to a normal pressure and this process is repeated at least once. CONSTITUTION:Seven sheets of polyester non-woven cloth H-8010, 10cmX10cm manufactured by Japan Vilene Co., Ltd. are used in a state of piling-up as a material 3 to be impregnated. After the inside of a vacuum tank 1 is decompressed to degass the air contained in the material to be impregnated, an impregnated synthetic resin 4 is agitated and defoamed by a hopper. After the synthetic resin 4 is gradually poured into an impregnating tub 2 from its bottom until the material 3 to be impregnated is completely covered with, the inside of the vacuum pressure tank 1 is raised back to a normal pressure (1 atmospheric pressure). After decompressed by way of the same condition and procedure as mentioned above, it is raised back to a normal pressure. This process is repeated. By this method, the number of inevitably generating void can be minimized. |
