Organic microballoon

Abstract

Inorganic fillers such as silica balloons are used as a lightweight filler for resin moldings. But the specific gravity of these inorganic fillers is about 0.2 at most, so that there is a limit to reduction in weight. The foamed product of organic polymers is obtained as a lightweight substance, but it is hardly put to practical use because of its poor solvent resistance and thermal resistance. The microballoon of the present invention is produced by coating the surface of a hollow particle having the wall film of a thermoplastic high polymer with a thermosetting resin. The present invention provides a microballoon having excellent solvent resistance and thermal resistance as well as a very low specific gravity, and said microballoon is useful as a lightweight filler for resin moldings, aggregate for FRP, ingredient for paints, and the like.

Dependencies are inferred from the claim text.