| 摘要 |
PURPOSE:To improve smoothness of a surface, by a method wherein by making glass paste for forming heat reserving material contain an inorganic blowing agent of a decomposition temperature which is higher than a softening temperature of glass powder, the inorganic blowing agent is made not to be decomposed when it is printed and baked on a base board. CONSTITUTION:An inorganic blowing agent having a decomposition temperature higher than a softening temperature of glass powder is contained in glass paste. The inorganic blowing agent necessarily has the decomposition temperature higher than the softening temperature of the glass powder and various kinds of inorganic blowing agents can be independently or, in a blended manner, utilized. Carbonates such as carcium carbonate, barium carbonate, magnesium carbonate, etc., or silicates such as calcium cilicate or the like and others are concretely exemplified. However, since heat reserving material basically functions as an electrical insulating layer, one containing no alkaline metal is especially preferable. It is preferable that an activity ratio of those inorganic blowing agents is 5:95-30:70 by weight ratio to glass powder, or otherwise their decomposition temperature is especially 50-150 deg.C higher than the softening temperature of glass powder by considering that bubbles can be, in a good state, formed in the heat reserving material.
|
