Innovative solutions for flame retardants in polyurethane foams

In our homes, polyurethane (PU) foams are often found in upholstered furniture, which can represent a large fire risk. In this application, the addition of flame retardants can decrease the rate of heat generation, rate of fire growth and fire spread.

While there is a wide range of foamed materials with very different properties (from flexible to rigid foams), PU foams usually exhibit a low resistance to temperature changes provoked by a source of heat. This means that the heat does not dissipate deeply but rather stays in the surface layer. Simply put: the surface of the foam reaches high temperature quickly and ignites easily.

Traditional flame retardants, such as aliphatic chlorophospates or aliphatic phosphates, are used as flame retardants for PU foams. However, they can be quite volatile. This does not undermine their efficiency, but it does mean that they can end up migrating in the environment.

We decided to look for effective solutions to tackle this migration issue. We found that the best way to proceed was to use polymeric or reactive flame retardants for PU foams, because of their respective characteristics.

Indeed, the potential of polymeric molecules to migrate from foam is very low due to their large size, which also makes them unlikely to penetrate living organisms’ cells. On the other hand, reactive flame retardants are built directly into the PU polymer chains, making it impossible to migrate from the polymer into the environment.

Polymeric and reactive flame retardants are also extremely cost-efficient. They can cut use dosage and, as a result, cost in use becomes similar and even more favourable than traditional flame retardants. Overall, these are two innovative solutions that are good for the environment and for health, while ensuring the highest level of fire safety.