PURPOSE: To separate the water-soluble impurities from the powder of uncured resin for the encapsulation of semiconductors, by curing the powder under the same conditions as the molding of the product, pulverizing the cured product, and extracting the powder by heating in a closed vessel having inner walls coated with a fluorine-contained resin.
CONSTITUTION: Only the uncured resin powder is put into a mold same as the mold for the molding of a product, and molded and cured preferably at 180°C and 80kg/cm2 for 10min. After the after-cure at 180°C for 3hr, the cured product is pulverized, and put into a stainless steel vessel having a thickness of about 5mm and coated its inner walls with a fluorine-contained resin (e.g. tetrafluoroethylene polymer) with a thickness of about 3mm. Water is poured into the vessel, and stirred. The water-soluble impurities are separated by the extraction in the extractor at 140W220°C for about 2hr.
ENDOU HIROSHI
PHOSPHATE ROCK ANALYSIS=1974
A LITERATURE SURVEY ON APPLICATIONS OF UNISEAL DECOMPOSITION VESSELS IN CHEMICAL ANALYSIS AND RESEARCH 1968-1982