Abstract
The acid number of printing varnishes is one of the most important characterestics which affect the rheological property of printing inks. On the other hand, printing vehicles are different things from edible and cosmetic oils, ibecause, while the latters are rarely affected by remaining a small amount of water and/or soaps after acid refining, the former is seriously affected by remaining those. So I tried to depress the acid number of the printing varnishes (heat-bodied linseed oils) by esterification with glycerin, in stead of saponification with NaOH alkali solution.
As results, it was revealed the printing varnish having lower acid number and useful for printing could be obtained by thermal esterification with glycerin without any special operation like as agitation.
