| abstract |
This disclosure provides for new polyisocyanurate (PIR) foams that exhibit improved flame retardant properties and thermal barrier properties, and which can pass certain thermal barrier tests in the absence of a protective covering such as specified in the thermal barriers codes. In an aspect, it has been unexpectedly discovered that when a relatively high viscosity and high functionality polyisocyanate is used with a high aromatic content polyester polyol and an HFO and/or HCFO blowing agent, and a flame retardant compound, unexpectedly good flame retardant polyisocyanurate foams can be generated, for example, when a high A-side:B-side volume ratio (v:v) and a relatively high Isocyanate Index (ISO Index) are used in the process. |