polyvinyl acetal: Meaning and Definition of

pol'yvi'nyl ac'etal

1. any of the class of thermoplastic resins derived by the condensation of an aldehyde with polyvinyl alcohol.
2. the slightly yellow, water-insoluble resin produced from partially hydrolyzed polyvinyl acetate and formaldehyde: used chiefly in the manufacture of lacquers, photographic film, and adhesives.