| 摘要 |
The invention relates to highly shear-thinning polyvinyl acetals, characterized in that their solution viscosity decreases by at least 30 % in a 30 % by weight solution in methyl ethyl ketone with a shearing rate ranging from 1 to 100 s<SUP>-1</SUP>. The invention also relates to a method for producing highly shear-thinning polyvinyl acetals by acetalizing partially saponified or completely saponified vinyl ester polymers with = 50 mol % vinyl alcohol units with one or more aldehydes, optionally in the form of their hydrates, hemiacetals or full acetals, characterized in that the aldehyde portion is completely added by metering within a period of no longer than 15 minutes. |
