PROCESS FOR PREPARING POLYVINYL BUTYRAL WITH IMPROVED PROPERTIES.

摘要

The preparation of polyvinylbutyral is commonly effected by the acetalization of polyvinyl alcohol with n-butyraldehyde, either in an organic solvent or in water. By varying the reaction conditions it is possible to obtain the polyvinylbutyral in a coarse-grain or fine-grained form. The production of polyvinylbutyral having improved properties is possible by using a polyvinylbutyral having a content of from 17 to 24% by weight of vinyl alcohol units as starting material for an after-treatment in the presence of an organic sulfonic acid having an emulsifying effect. The polyvinylbutyral obtained is particularly suitable for the manufacture of compound sheets.