Author: Eugene Stukanov, Ph.D., Head of the Laboratory Centre Ltd. "Elastokam" Science and Technology - a joint venture PJSC Nizhnekamskneftekhim and BASF Polyurethanes GmbH.
Polyisocyanurate (PIR) panels are widely used in the construction industry as a thermal insulation with decreased flammability in contrast to conventional PUR foam. The improved fire behavior of PIR panels is a result of polyisocyanurate moieties presence in polymer matrix that can be formed in special conditions including polyol composition (Component A), considerable excess of isocyanate (Component B) and particular production line parameters.
Today polyurethane (PU) and its less flammable brother polyisocyanurate (PIR) are the most effective thermal insulation. It should be noted that the thermal conductivity value (Lambda) is affected by several factors and the cell gas that originates from the use of a particular blowing agent has the highest impact . Blowing agents can be devided into two groups: chemical (water, formic acid) and physical blowing agents (CFCs, HFCs, HCFCs, pentanes, methylal – inert organic substances with low boiling point). Chemical blowing agents react with isocyanates and one the products of such interaction is carbon dioxide. Cell gas formation in case of physical blowing agent is a result of boiling of a liquid during the exothermic reaction of A and B components.