The use of citric acid in the production of polyols for rigid PUR-PIR foams

Abstract

The article describes the method of obtaining new, cheaper compounds which can substitute polyols in the production of rigid polyurethane-polyisocyanurate foams (PUR-PIR). Rigid PUR-PIR foams were synthesized, using newly obtained tree compounds (citrates with hydroxyl groups): obtained with using catalyst (T-2-HHT + K), without catalyst (T-2-HHT) and (T-5-HHT). New compounds (T-2-HHT + K, T-2-HHT, T-5-HHT) were prepared from citric acid (1 mol) and glycols, respectively: butane-1.2-diol (3 mol and excess of 30 cm3), butane-1.2-diol (3 mol), pentane-1.5-diol (3 mol) by the esterification reaction in the solution. The industrial Rocopol 551, used as polyol, was gradually substituted for the new compounds in the polyol premix in new foams. The three series of rigid polyurethane-polyisocyanurate foams based on T-2-HHT + K, T-2-HHT, T-5-HHT have been synthesized (F1–F16) and W foam without new compound. Its properties have been determined according to the standards. It has been shown that the addition of T-2-HHT + K, T-2-HHT, T-5-HHT to the foams affects the foams’ density. The influence of the abovementioned compounds on foams’ flammability, thermal properties and others was examined. A decrease in foams’ brittleness by 6.9 % and in oxygen index by 24 % was observed. The examined retention was in the range of 80.9–96.5 %.