Flame retardants (FR) are used in plastic components to make them fire resistant. Their use is critical when plastic is in contact with electric currents over 24 volts, as they inhibit combustion in case of a short circuit, or when it is exposed to live flames.

There are two types of flame retardants:

• Halogen-based: these FRs use halogenated molecules that use highly reactive elements like chlorine or bromine; decabromodiphenyl oxide is the most commonly used. These elements are very efficient flame retardants, but can be very harmful when released as gas.
• Halogen-free: these FRs include alumina trihydrate (ATH), magnesium hydroxide (MDH), phosphorus compounds and melamine cyanide. Halogen-free additives must be incorporated in larger amounts than halogen-based FRs, thus impacting on the polymer’s mechanical properties, which can in turn change the part’s geometry.

Salmon has both types of flame retardant in its portfolio. We have three grades of MDH, two are a mineral called brucite with different particle sizes, and the other is a synthetic grade, with higher purity and concentration. FKMT are market leaders in China in the production of MDH, and the only producer in the world that produces both mineral-based and synthetic grades. For these products we work with our trusted partner KMT. KMT are market leaders in China in the production of MDH, and the only producer in the world that produces both mineral-based and synthetic grades.

To meet existing demand for halogen-based FRs, we also supply zinc bromide, which acts as a smoke suppressor. This is an important additive for PVC formulations, as this polymer can otherwise release very toxic fumes when combusted, which can be very dangerous in closed spaces.

We also supply two bromide-based compounds, which are added in much smaller quantities than halogen-free flame retardants. For these products we work with Oceanchem, who have been developing products for this sector since the 1990s. The demand for flame retardants has grown considerably in recent years as a direct result of the growth of electrical products, from house goods to EVs. At the same time, increased awareness of the dangers of the burning of PVC compounds, these have been progressively replaced with polyolefins, which use MDH and ATH as flame retardants. The market is steadily shifting from halogen-based to halogen-free FRs.