METHOD OF POLYVINYL ALCOHOL SYNTHESIS Russian patent published in 1994 - IPC

FIELD: chemical technology. SUBSTANCE: polyvinyl alcohol is synthesized by saponification of polyvinyl acetate in the form of latex using alkali as a catalyst. Mixing of polyvinyl acetate latex and aqueous solution of saponification catalyst is carried out at 0-22 C. Saponification is carried out at the range 0-80 C. At the end of saponification when process is actually finished concentration of electrolytes is made 2.5 g-equiv./l, not less. To improve polyvinyl alcohol precipitate isolation suspension is heated up to 90-140 C, and aqueous solution of polyvinyl alcohol is poured in. Quantity of pouring in polyvinyl alcohol is 1.2-2.5 wt.-% of polyvinyl alcohol content in suspension. It is possible to heat and add the additional quantity of polyvinyl alcohol aqueous solution simultaneously. Product is used for plastics preparing. EFFECT: improved method of polyvinyl alcohol synthesis. 1 tbl