Polyvinyl Butyral Resin: Polyvinyl Acetate and Butyraldehyde in Methanol with Acid at 45 °C (Perkins, Union Carbide, US 2,194,613)

In dry methanol with an acid, polyvinyl acetate loses its acetate groups and, in the same pot, the freed alcohol groups take up butyraldehyde. Perkins' one-step process gives the partial polyvinyl butyral that sticks so well to glass. Result: polyvinyl butyral resin, a white powder once precipitated and dried. Source: Perkins, US 2,194,613 (Union Carbide, 1940), Example II. Not given: yield. Picture drawn by Youblob.