| 摘要 |
<p>HIGHLY ACETALIZED, COARSELY GROUND POLYVINYL ACETOACETALSThe invention relates to highly acetalized, coarse-grained polyvinyl acetals with a degree of acetalization of > 80 mol% and an average grain size of ?. 100 pm obtainable by acetalization of partially or fully hydrolyzed polyvinyl esters with a degree of hydrolysis of ?_ 70 mol% with acetaldehyde, characterized by the fact that the acetalization is started at a temperature T1 of 0°C•+20°C and is then continued at a temperature T2 of > +40°C, wherein the temperature T2 is held for a time period of 0.05 to 4 hours and the acetalization is performed in a closed reactor.</p> |
