| 摘要 |
Polyvinyl alcohol prepared by alkaline hydrolysis is stabilized by neutralizing the polyvinyl ester hydrolysate from which it is produced with phosphoric acid and washing the resin with an organic liquid selected from methanol, ethanol, methyl acetate, ethyl acetate and acetone. Specified polyvinyl ester starting materials are polymers and copolymers of vinyl acetate, propionate, butyrate, hexoate and benzoate and copolymers thereof with other vinyl esters such as vinyl stearate, vinyl halides, acrylic and methacrylic acids and esters, and olefins. Examples describe the neutralization with phosphoric acid of (1 to 3, 5 and 7) polyvinyl acetate hydrolysed with sodium hydroxide in methanol with (3) methyl acetate; and (4) a vinyl acetate-vinyl chloride copolymer hydrolysed with sodium hydroxide in methanol; the products being washed with methanol. |
