Pressure-sensitive adhesives exhibiting an improved shear strength at elevated temperatures

Abstract

The invention relates to pressure-sensitive adhesive layers produced from aqueous dispersions consisting of polymers with isocyanate-reactive groups and of surface-deactivated solid isocyanates whose shear strength can be improved by elevated temperatures. In a first step, a property profile results after water is removed by drying at drying temperatures (a) ranging from 20° C. to 95° C. Said property profile can be influenced in a second step, by a thermal treatment (b) on the single or double-sided-pressure-sensitive adhesive tape or transfer tape or on the finished bonding, in order to improve shear strength (or rather to render it less inclined to creeping) with an acceptable loss of surface adhesiveness. The duration of the thermal treatment (b) ranges from a m of 5 seconds at 135° C. (or higher temperatures) to a maximum of 30 minutes at 90° C. (measured in the layer). The maximum temperature of the thermal treatment (b) exceeds the drying temperature (a) by at least 40° C. The cross-linked pressure-sensitive adhesive layers are used in high-performance adhesives, which are creep-resistant at high temperatures, in adhered joints in assembling and manufacturing processes, in adhesive tape configurations used in the field of fastenings, which can be statically subjected to stresses. They can also be used for fastening bondings with increased temperature stability and shear strength.

Dependencies are inferred from the claim text.