Frothing of cavity structures in coating layers to reduce specific weight

Possibilities for the in-situ production of cavity structures based on PUR or on aqueous carbonate systems were developed for paper and board coating. The greatest challenge was the nondestructive application of foams and froths, which required individual solutions in each and every case. As a result, a reduction in the specific weight ranging from 15% to 300% could be achieved. The samples obtained exhibited not only a savings in specific weight but also a potential for applications involving thermal insulation properties. Depending on the reaction pathway, it was possible to thus achieve a reduction in specific weight ranging from 15% to 39%. Printability was found to be good, as were the converting properties.