SEALING COMPOSITION Russian patent published in 2003 - IPC

FIELD: sealing materials. SUBSTANCE: invention relates to sealing compositions ensuring processibility and tightness of the processes of vacuum and vacuum-autoclave molding of products from polycrystalline materials and metals. Composition contains, wt. parts: butyl rubber, 55-65; chlorobutyl rubber, 35-45; colophony, 10-20; softener; carbon white, 25-35; chalk , 140-160; zinc oxide, 4-5; and stearic acid, 2-4. Invention allows increasing stability and reliability of molding process owing to smooth vulcanization process at high temperature (150 C and higher) and also allows using, for manufacturing sealing compositions, less power-consuming and more productive equipment, in particular mixer instead of rollers due to combining high- activity chlorobutyl rubber with low-activity butyl rubber with unsaturation percentage 1.5-2.0%. EFFECT: expanded molding possibilities and reduced production expenses. 2 cl, 2 tbl