| 摘要 |
<p>A process is provided for improving heat insulating articles which contain silicon dioxide having a surface area of at least 50m2/g, opacifiers and, if desired, inorganic fibers, The improvement involves -treating the surface of the insulating articles with at least one organosilicon compound containing from 1 to 4 silicon atoms to render such surface hydrophobic. The particular organosilicon compound used is selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane and silicon compounds of the formulas (R3Si)aZ and Ra SiZ'4-a ' in which R is selected from the group consisting of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, Z is selected from the group consisting of hydrogen, halogen, OH, -OR', -NR'X, -ONR'2, -SR', -OOCR', -O-, -NX and -S-, Z' is selected from the group consisting of hydrogen, halogen, -OH, -OR', -NR'X, -ONR'2, -SR' and -OOCR', R' is a radical having from 1 to 4 carbon atoms, X is selected from the group consisting of hydrogen and R' and a is 1 or 2. These heat insulating articles not only have hydrophobic properties, but also retain their mechanical strength. The improved heat insulating articles may be employed to insulate heat storage facilities, in stove heating elements, as components to heaters, and for embedding heating coils.</p> |
