definition
strict definition
polyisocyanurate rigid panels
Hard insulating panels made from polyisocyanurate, a plastic similar to polyurethane.
Polyisocyanurate rigid panels are hard panels for thermal insulation made of polyisocyanurate, a form of plastic very similar to polyurethane but with somewhat better insulating properties.
The panels use polyisocyanurate as the insulating plastic. They are installed as hard sheets rather than as loose fibers or an injected cavity fill.
Polyisocyanurate and polyurethane are related materials but retain separate panel categories. Similar appearance or use does not make their chemical compositions identical.