FOERFARANDE FOER FRAMSTAELLNING AV FENOLSKUM UPPVISANDE CELLVAEGGAR SOM AER VAESENTLIGEN FRIA FRAAN PERFORERINGAR OCH SPRICKOR ORSAKADE AV VATTEN

摘要

The present invention is directed to a method of preparing a phenolic foam that has cell walls which are substantially free of perforations. The method comprises using certain anhydrous aryl sulfonic acids as the foaming and curing catalysts. The useful anhydrous aryl sulfonic acids are those which have a pKa of less than about 2.0 and which change the compatibility of the phenolic resole with water. The preferred anhydrous aryl sulfonic acid is a combination of toluene sulfonic acid and xylene sulfonic acid. The invention is also directed to a phenolic foam having cell walls which are substantially free of perforations and to foamable phenolic resole compositions for preparing the phenolic foam.