Polyvinyl alcohol is used as an emulsion polymerization, as protective colloid, to make polyvinyl acetate dispersions. This is the largest market application in China. Some other uses of polyvinyl alcohol include:

.Paper adhesive with boric acid in spiral tube winding and solid board production

.Thickener, modifier, in polyvinyl acetate glues 

.Textile sizing agent

.Paper coatings ,release liner 

PVA is unique among polymers (chemical compounds made up of large, multiple-unit molecules) in that it is not built up in polymerization reactions from single-unit precursor molecules known as monomers. Instead, PVA is made by dissolving another polymer, polyvinyl acetate (PVAc), in an alcohol such as methanol and treating it with an alkaline catalyst such as sodium hydroxide. The resulting hydrolysis, or “alcoholysis,” reaction removes the acetate groups from the PVAc molecules without disrupting their long-chain structure. 

Dissolving Device

■Vessel

PVA is usually processed in the form of aqueous solution. Since the solution is slightly acidic (pH 5~7), vessel

should be made of materials, which will not contaminate the solution with corrosive material or rusts. Stainless

steel vessel, enameled containers or polyester tanks are recommended.

The specific gravity of PVA is ranging from 1.26 to 1.31, which is heavier than that of water. Low agitation speed

or unfavorable agitating condition sometimes causes coarse particles to precipitate and to block the outlet of

the dissolving tank. Hence, a flush valve or tank valve is recommended to be installed in the bottom of the vessel to prevent the particles from blocking the discharge line.