The term 'rigid polyurethane insulation'
covers the family of insulation materials based on PUR (polyurethane)
or PIR (polyisocyanurate).
Polyurethane is a generic term, which covers
a wide range of different formulations. The main linkage
formed during polymerisation is the urethane group, but other
linkages such as isocyanurate, urea, and others may be introduced
to a varying degree.
Isocyanurate modified polyurethane foams,
for example, generally show better heat resistance, lower
volatiles production and better char formation than standard
PUR. We call them PIR.
