FORMIC-ACID AS A CO-BLOWING AGENT IN RIGID POLYURETHANE FOAMS

A valid substitute for CFC-11 (trichlorofluoromethane) for the product ion oi rigid polyurethane foams for thermal insulating materials, with blowing agents having low environmental impact, is nor available yet. HCFC-141b and n-pentane, at present the most utilized physical blowin g agents (PBAs), cannot definitely replace CFCs because of their envir onmental impact and flammability, respectively. The aim of the present work is to investigate the opportunity of employing HCOOH as a chemic al blowing agent (CBA). other than water, which can in some applicatio ns replace physical blowing agents. Advantages and disadvantages have been highlighted after studying the isocyanate-formic acid reaction. E vidently, the introduction of new reactions into the polyurethane chem istry introduces a wide range of opportunities and challenges. (C) 199 8 Elsevier Science Ltd. All rights reserved.