Polyisocyanurate (PIR)
Polyisocyanurate (PIR) is formed as a result of the chemical reaction between the PMDI (polymeric methyl diphenyl isocyanate) or MDI and polyol. The amount of the mixture of MDI and polyol components differs polyisocyanurate from polyurethane.
The amount of MDI used in PIR production and the amount of the flame retardant catalyst are higher. PIR is composed of isocyanurates chains which have higher
chemical stability at high temperatures. PIR’s flammability and smoke generation is very low compared to polyurethane. It creates excellent thermal insulation due to its closed cell structure. PIR should be used at maximum 80-90°C. Its maximum resistance temperature is 100-110°C. After this temperatures, it loses its function.
| PIR Laboratory Values | Value |
|---|---|
| Application Temperature (°C) | -40 ~ +90 |
| Thermal Conductivity Coefficient (l-W/mK) | 0,020 |
| Compressive Strength - 10% expanded (N/mm²) | 0,15 – 0,20 |
| Bending Strength (N/mm²) | 0,24 – 0,30 |
| Water Absorption (after 168 hours - %) | 0,05 – 0,20 |
| Steam Diffusion Resistance ( µ ) | 55 – 60 |
| Fire Class | B1 (DIN 4102) |
| Closed Cell Content | 91-95% |