White standard paint
Patent No. U.S. 6,555,608 B2
Kabushiki Kaisha Topcon, Tokyo, Japan, has been granted a patent for a white standard paint that is comprised of barium sulfate, a binder and a solvent. Polyvinyl alcohol is used as an ingredient of the binder. The polyvinyl alcohol has a polymerization degree ranging from 900 to 1100 and a saponification degree ranging from 86 mol percent to 90 mol percent, wherein the barium sulfate has a purity degree of 99.9% or more.