Polymer based on polyvinyl alcohol and process for their manufacture.

Method for producing an alcohol-based polyvinyl comprising polymer: the progress of a reaction of transesterification of an ester based polyvinyl alcohol in a liquid reaction mixture comprising the ester based polymer, polyvinyl alcohol polymer and a basic compound; precipitation of the polymer based on polyvinyl ester, of which at least one part has been transesterified with the alcohol, out of the liquid reaction mixture; and further progress of the transesterification reaction in the liquid reaction mixture that includes based on polyvinyl ester that has precipitated polymer characterized in that the liquid reaction mixture has a temperature of 75 to 150 when the polymer based on polyvinyl ester , of which at least part has been transesterified, starts to precipitate.