What is The Best Type of Flame Retardant for You?
Because of legislation and the ever-increasing demands consumers put on products, the plastics and textiles industries have been forced to make many of their products flame retardant. They have added chemicals to help prevent the finished good from bursting into flame. There are many different ways to prevent flames and the different types of flame-retardants are used in different applications because of their flame retarding abilities and other chemical properties.
Endothermic degradation is one method used by certain types of flame-retardants. Endothermic degradation means that the chemical compounds breaks down when introduced to high temperatures and that chemical process absorbs heat and energy from the surrounding materials and environment. While the endothermic reaction is absorbing the heat, the material that is exposed to the flame cools and prevents fire from catching. Examples of chemicals that use this method are hydrates, aluminum hydroxide and magnesium hydroxide. Some plastics manufacturing processes get very hot and these chemicals cannot be used because the operating temperature is above the temperature of degradation.
Intumescents are another type of flame retardant. An intumescent additive is one that swells when exposed to heat. If the intumescent additive is in the plastic or textile coating and is exposed to a flame, the plastic or coating turns into a carbonized foam. The foam acts as a thermal barrier between the burning portion of the product and the portion that has not become fuel yet. This method is called thermal shielding. Using intumescents will not prevent fire from catching, but it will significantly slow the progress of a fire.
The degradation of halogenated compounds is the most common type of flame retardant used. When used in synergy with antimony trioxide, halogen compounds are the most widespread flame retardant used today. Heat will cause brominated or chlorinated compounds to degrade and release hydrogen bromide and hydrogen chloride. The hydrogen bromide and chloride react with the hydrogen and hydroxyl radicals that are present in the ensuing flame to create water and bromine and chlorine radicals. The halogen radicals are far less reactive than the hydrogen and hydroxyl radicals are, so the combustion reaction slows down.
Some plastics are simply diluted with fillers so that there is less combustible material present. Common fillers are talc and calcium carbonate. If there is less combustible material then there will be less heat produced per a particular volume of material when it is burning. This method is sometimes called dilution of fuel.
As necessary as flame retardants are and as many lives as they have saved, there are some environmental and health concerns with certain types. Specifically, brominated flame-retardants are under a lot of scrutiny. Some particular compounds have been banned in Europe like polybrominated diphenyl ethers (PDBEs). However, there have been no concrete scientific studies that show the harmful effects of the vast majority of brominated flame-retardants. Furthermore, there is no other flame retardant that works as well as the halogen/antimony combination.
Most flame retardant products have that feature because some government body mandates it. The flame retardant industry is a regulated one and there are several different standards. When looking for a flame retardant additive, make sure that it meets whatever standard is appropriate for your industry and your country.




