| 摘要 |
PURPOSE:To provide a filler for resin, composed of uncrushed powder of fused silica having low alkali content, having excellent electrical insulation property, capable of being compounded in a resin in high concentration, and useful as a sealing material of electronic parts and insulation material of electrical parts. CONSTITUTION:The objective filler is composed of uncrushed powder of fused silica having an alkali content of <=0.5wt% and obtained by blasting powder of e.g. quartzite, quartz, silica sand, etc. having a diameter of <=500 together with combustible gas and oxygen into a vertical furnace and fusing instantaneously at >=1,700 deg.C.
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