Methods for determining the number of closed cells in rigid sprayed polyurethane foam

Abstract

Polyurethane foams are currently the most effective thermal insulation materials, polyisocyanurates have low combustibility. Predicting the number of closed cells forming a gas-filled matrix in the finished polymer is necessary to improve the quality and durability of rigid sprayed polyurethane foam (SPF) and also be able to determine their quantity in finished coatings using standardized techniques. Depending on the number of closed cells, the polyurethane coatings are classified into certain levels in European documents. The methods of determining the volume percentage of open and closed cells of polyurethane foam, the problems of applying these methods, measuring equipment and their errors are analyzed in the article. The authors analyzed the international standard ISO 4590 for determining the volume percentage of open and closed cells spread in the EU countries and the American standard ASTM D 6226 for the purposes of harmonization of European standards with the developed national standard for PUR insulation and polyisocyanurate (PIR), sprayed on the site of production.