DEFINITION

Polyvinyl Alcohol is a water-soluble synthetic resin, represented by the formula (C₂H₄O) _n , in which the average value of n lies between 500 and 5000. It is prepared by 85%–89% hydrolysis of polyvinyl acetate. The apparent viscosity, in mPa·s, at 20°, of a 4% (w/w) aqueous solution is NLT 85.0% and NMT 115.0% of that stated on the label.