Hoechst Aktiengesellschaft

Hans-Dieter Hermann

Matthias Kroggel

Karl-Josef Rauterkus

Polymers with polyvinyl acetal groups, which contain acetalized polyvinyl alcohol groups on polyurethane grafting substrates and which are prepared from graft polymers, containing vinyl alcohol groups on polyurethane grafting substrates, by reaction with aldehydes according to known methods. The aldehydes used can be any known aldehydes capable of acetalization reactions. The polyurethane grafting substrates contain at least 2 urethane groups in the molecule and units from diisocyanates and diols, and polymer radicals of units of vinyl carboxylates having 3 to 20 carbon atoms and/or hydrolysis products thereof and, if appropriate, further monomer units are grafted onto the polyurethane grafting subtrates. The proportion of vinyl alcohol units in the hydrolyzed or partially hydrolyzed graft polymers before the acetalization is &gt;10% by weight. In the acetalized polymer, the content of residual unacetalized vinyl alcohol units is &gt;7.5 mol %, relative to the molar content (=100 mol %) of vinyl alcohol units in the starting graft polyvinyl alcohol before acetalization. Use of the graft polyvinyl acetals as a constituent of coating compositions, as a coating agent constituent for the diverse substrates, as a material for thermoplastically processable moldings and as an interleaving film in laminated glasses.

Graft polymers, containing polyvinyl acetal groups, on polyurethane

Polymers with polyvinyl acetal groups, which contain acetalized polyvinyl alcohol groups on polyurethane grafting substrates and which are prepared from graft polymers, containing vinyl alcohol groups on polyurethane grafting substrates, by reaction with aldehydes according to known methods. The aldehydes used can be any known aldehydes capable of acetalization reactions. The polyurethane grafting substrates contain at least 2 urethane groups in the molecule and units from diisocyanates and diols, and polymer radicals of units of vinyl carboxylates having 3 to 20 carbon atoms and/or hydrolysis products thereof and, if appropriate, further monomer units are grafted onto the polyurethane grafting substrates. The proportion of vinyl alcohol units in the hydrolyzed or partially hydrolyzed graft polymers before the acetalization is &gt;10% by weight. In the acetalized polymer, the content of residual unacetalized vinyl alcohol units is &gt;7.5 mol %, relative to the molar content (=100 mol %) of vinyl alcohol units in the starting graft polyvinyl alcohol before acetalization. The graft polyvinyl acetals may be used as a constituent of coating compositions, as a coating agent constituent for the diverse substrates, as a material for thermoplastically processable moldings and as an interleaving film in laminated glasses.

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Bad Soden am Taunus, Germany

Hans-Dieter Hermann