Why it matters
R-Value is the headline thermal-resistance number on every insulation spec sheet, but it is the inverse of K-Factor (thermal conductivity) — the property formulators actually engineer. In polyisocyanurate (PIR) foam, K-Factor is governed by three things: the gas trapped inside the closed cells, the cell size and uniformity, and how that gas mix changes over time as air diffuses in (LTTR — long-term thermal resistance).
Tightening cell structure and stabilizing the blowing-agent gas is where additive chemistry matters. A poorly-cell-stabilized PIR system will show beautiful initial R-value and degrade two or three points by year five.
How MCPU solves it
Yellow Jacket™ TR is a reactive cell-structure modifier that participates in the urethane reaction during rise, producing finer, more uniform closed cells. The result is a measurably lower K-Factor at the same density, and — more importantly — a flatter aging curve.
Used alongside hydrofluoroolefin (HFO) blowing agents, Yellow Jacket™ TR helps deliver LTTR values that hold up to ASTM C1289-spec aging tests without forcing the formulator to chase higher densities.
Test data & spec snapshot
Representative values — actual performance depends on your formulation. Pilot data available on request.
| Mechanism | Reactive cell-structure modifier |
|---|---|
| Compatible blowing agents | HFO, HFC, water-blown, hybrid |
| Typical loading | 2–6 phpp |
| Effect | Finer, more uniform closed-cell structure |
Typical applications
- Polyiso roofing boardstock targeting LTTR ≥ 6.0 per inch
- Wall insulation panels
- Refrigerated transport panels