A new macro molecule called is created polyisocyanurate (PIR) by reaction of isocyanate that is one of the basic polyurethane foam components and isocyanate molecules. Polyisocyanurate is created as a result of chemical reaction between polymeric methyl diphenyl isocyanate or methyl diphenyl isocyanate and polyol and what polyisocyanurate differs from polyurethane is combination amounts of methyl diphenyl isocyanate and polyol components.
Methyl diphenyl isocyanate amount used for PIR production is much and it reacts each other apart from polyol. Then isocyanurate chains whose chemical stability is higher at high temperatures are created. These chains are stronger than normal polyurethane chains.
In compared with PUR, due to difference of its structure, it’s flammability and smoke generation is low. Foam cell structure.