| 摘要 |
The invention relates to an energy-saving and time intensive method for producing polyvinyl acetals, which also has economical advantages for, in particular, the thermoplastic processing of polymers. According to the inventive method, at least one polyvinyl alcohol and/or a vinyl alcohol-copolymer is reacted with at least one carbonyl compound of formula R<SUP>1</SUP>C(O)R<SUP>2</SUP> in the presence of an acid catalyst, wherein R<SUP>1 </SUP>and R<SUP>2</SUP>independently represent hydrogen, COOH, COOM, an optionally, substituted alkyl group having 1 - 10 carbon atoms or an optionally substituted aryl group having 6 12 carbon atoms and M is a metal cation or, an optionally alkylated ammonium cation. The inventive method is characterised in that the reaction takes place in the presence of at least one hydrophobic softener which was has a distinct effect on the heat-modification of the polymers. The obtained plasticised polyvinyl acetals are dried using considerably low energy and/or over a short period of time and are characterised by an accelerated softener receiving element. The invention relates to the production of polyvinyl acetals which are used, in particular, for the extrusion of films for producing safety composite glass. |
