Abstract
We found that the best evaluation method of the adhesiveness of the shellac basing cements for electron tube is to keep the electron tube for 24 hours in a closed vessel, having a humidity of about 80%, and then conduct the 22kg-cm torque test.
The followings are our conclusions about the improvement of the adhesiveness of shellac basing cements:
(1) The base is assembled after the shellac resin solutions have been coated on the surface of glass bulb.
(2) The minimum temperature of 158°C is necessary for the baking of the shellac cements.
(3) Dow Corning DC-804 silicone resin equal to 6% of the shellac resin in the basing cements is useful as an additive of basing cements.
