Polyisocyanurate boardstock and rigid PU panel foam are judged on three axes simultaneously: flame spread and smoke on ASTM E84, thermal conductivity at the rated aging interval, and dimensional stability through freeze-thaw and humid-aging cycles. Move one and the other two shift with it.
MCPU formulates on all three axes at once rather than patching a single failure. That means the flame-retardant package, the cell-opening and nucleation profile, and the crosslink density are chosen together against the index and line speed the plant actually runs.
What this application has to hit
- ASTM E84 Class A / UL 723 flame spread and smoke-developed performance
- Long-term thermal resistance stability (LTTR) at the aged interval
- Fine, closed-cell structure for low k-factor at target density
- Dimensional stability under humid aging and thermal cycling
- Friability and facer adhesion within line tolerance
How MCPU formulates for it
Yellow Jacket™ is developed to replace TCPP at comparable loadings, targeting Class A while removing halogen and cutting the smoke contribution that chlorinated phosphates carry — confirmed on your formulation.
Nucleation and surfactant selection tighten cell size so k-factor improves without raising density, and the isocyanurate index is set to keep char integrity through the burn.
Honey Bee® reactive modifiers can carry renewable content into the B-side without softening the matrix, because the hydroxyls react into the network rather than plasticizing it.
Formulation levers we adjust
| Lever | What it controls |
|---|---|
| Index | Isocyanurate index drives char strength and friability — tuned against facer adhesion. |
| FR package | Reactive vs additive phosphorus balance set by required loading and blend stability. |
| Cell structure | Surfactant and nucleation control k-factor at constant density. |
| Catalysis | Trimer/gel catalyst ratio matched to line speed and exotherm limits. |
Products used here
- Yellow Jacket™ — Halogen-free flame-retardant additive system for rigid PIR & polyurethane foam.
- Honey Bee® — Reactive soy-based polyols and modifiers for resilient, lower-carbon polyurethanes.
- Custom Formulation Development — Bench-to-plant formulation development, reverse engineering, and toll-blended production.