| 摘要 |
<p>PURPOSE:To improve electric properties and drill workability by placing the hollow spherical glass powder having specified specific gravity and average particle diameter in the resin with which the base material of a surface layer is impregnated of the laminate formed under heating and pressurizing after the sheetlike base materials impregnated with thermosetting resin have been laminated. CONSTITUTION:A laminate is formed under heating and pressurizing, after sheetlike base material impregnated with thermosetting resin has been laminated. Then, the hollow spherical glass powder having the specific gravity of 0.8-2 and the average particle diameter of at most 30mum is placed in the resin with which the base material of a surface layer is impregnated. In order to produce said laminate, the prepreg obtained by impregnating the sheetlike base material with thermosetting resin varnish and by drying it, is placed inside of the laminate. On one hand, the prepreg obtained by impregnating said base material with the thermosetting resin compounded with the hollow spherical glass powder having said properties, is placed on the surface of the laminate. Then, the laminate is completed by heating and pressurizing. consequently, while the occurrence of void is suppressed and electric properties are prevented from being lowered, its drill workability is improved.</p> |
