POLYVINYL ACETAL RESIN FOR COATING AND INK, AND COATING AND INK COMPOSITIONS

摘要

It is an object of the invention to provide a polyvinyl acetal resin for lacquer and ink, which can suppress the occurrence of coloring and a foul odor of the polyvinyl acetal resin itself even when no antioxidant is used at all therein, and a lacquer and ink composition which has excellent color and the high stability of viscosity in storing it for long periods. The invention provides a polyvinyl acetal resin for lacquer and ink synthesized by acetalization reaction of polyvinyl alcohol and an aldehyde, wherein a polymerization degree is 100 to 3,000, a proportion of a residual acetyl group is 25 mol% or less and a proportion of a residual hydroxyl group is 17 to 35 mol%; a content of the residual aldehyde is 100 ppm or less, a content of residual butyric acid is 100 ppm or less, a content of residual 2-ethyl-2-hexenal is 100 ppm, and a content of a residual acid catalyst is 300 ppm or less, and no antioxidant is remained at all therein.