The Necessity of Flame Retardant Polyurethane Foam

In annual fire incidents, a significant proportion of ignitions are caused by foam, including sofa fires and various ignitions from soft packaging. These incidents occur far too frequently. How can we fundamentally eliminate or reduce such events?

One effective approach is to start from the source materials, much like treating the root cause of an illness. Adding flame retardants to polyurethane foam can effectively prevent ignition.

Now, let's understand flame-retardant foam:

Flame-retardant foam, also known as fire-resistant foam, has a chemical name of polyurethane foam material, which is divided into soft foam (mainly used for furniture) and rigid foam (mainly used for insulation). Generally, it is a fireproof material synthesized by adding various flame retardants to polyurethane.

The product's fire-retardant effect meets the requirements of ASTM Standard 117 and national standards. The usage method is the same as regular foam.

The combustion of polymers is a very complex and intense oxidation reaction. The process occurs as the polymer is continuously heated by an external heat source, initiating a free radical chain reaction with oxygen in the air. This releases some heat, further intensifying the degradation of the polymer, generating more flammable gases, and making the combustion more severe.

There are two methods for the flame retardancy of fire-resistant foam:

One is to chemically introduce flame-retardant elements or groups containing flame-retardant new elements into the molecular structure of the foam. The other method is to add compounds containing flame-retardant elements to the foam. The former method uses flame-retardant substances called reactive flame retardants, while the latter method uses substances called additive flame retardants.

Currently, the vast majority of flame retardants used in foam are additive flame retardants, while reactive flame retardants are mainly used in thermosetting resins such as epoxy resins and polyurethanes. The primary function of flame retardants is to interfere with the three basic elements required for combustion: oxygen, heat, and fuel. This can generally be achieved through the following means:

Flame retardants can produce heavier non-flammable gases or boiling liquids that cover the surface of the foam, interrupting the connection between oxidation and fuel.

By absorbing heat through decomposition or sublimation, flame retardants reduce the surface temperature of the polymer.

Flame retardants generate a large amount of non-flammable gases, diluting the concentration of flammable gases and oxygen in the combustion area.

Flame retardants capture radical free radicals, interrupting the chain reaction of oxidation.