Aug 4, 2026 - 3 Minutes
What Is B-Side Shelf Stability and Why Is It Becoming a Bigger Concern?
By Caitlin Baker, Chemist
As the polyurethane (PU) foam industry continues to transition to hydrofluoroolefin (HFO)-based blowing agents, manufacturers are realizing that achieving great initial performance is only part of the equation. Maintaining that performance over time can be just as important.
Materials such as Arkema's Forane® FBA 1233zd help manufacturers meet demanding performance and sustainability goals through ultra-low global warming potential (GWP), excellent insulation efficiency, and compliance with evolving regulations. However, like any advanced HFO-based system, long-term stability of the B-side polyol blend requires careful attention.
The good news? Although shelf-life limitations continue to be a common industry challenge, the right formulation, storage, and handling practices can help improve product stability and reduce the risk of premature degradation.
What Is B-Side Shelf Stability?
Shelf stability refers to a formulation's ability to maintain its original properties and performance over time while in storage.
For polyurethane foam systems, the B-side is a complex blend of polyols, catalysts, surfactants, flame retardants, blowing agents, and other additives. Because so many components are working together, maintaining long-term consistency can be challenging.
B-side stability isn't driven by just one factor. It's a combination of formulation chemistry, storage conditions, and time.
Several factors can contribute to stability decline:
- Moisture uptake
- Phase separation
- Blowing agent behavior
- Catalyst stability
- Temperature and air exposure
- Storage duration
Even small changes in the blend can affect processing and foam performance.
More Than a Lab Issue
It's easy to think of shelf stability as a technical formulation concern, but its impact extends far beyond the laboratory.
As a blend ages, gradual changes can occur within the formulation. Components can interact differently, reactivity can shift, and consistency may become more difficult to maintain. These changes don't always happen suddenly. They can develop over weeks or months in storage.
The result is less predictability in production and greater risk of variability in the final foam.
As HFO-based technologies continue to gain adoption, understanding and managing shelf stability is becoming an increasingly important part of building robust, reliable foam systems.
Next in our series: Why shelf stability matters from an operational and business perspective, and the hidden costs that can come with instability.
Caitlin Baker is a Chemist in the Fluorochemicals group at Arkema’s Technical Center in King of Prussia, PA. She received a B.A. in Biochemistry with minors in Mathematics and Biology and an M.S. in Forensic Science and Law from Duquesne University. Caitlin began her career with Arkema as a summer intern in the Foam Applications group.