Polyvinyl alcohol is a water-soluble synthetic polymer. It is the major protective colloid used in PVA adhesives. The properties of the adhesive are strongly influenced by the properties and concentration of the polyvinyl alcohol used in the preparation, or added during compounding. It can be manufactured by acid or alkaline hydrolysis or methanolysis of polyvinyl acetate. It is marked according to its degree of hydrolysis from the parent polyvinyl acetate, and also its solution viscosity.