Fire retardants are substances that are used to stop or slow down the spread of fire or minimize its intensity. This function is usually achieved by chemical reactions that inhibit the flammability of fuels. These chemical compounds can also delay the combustion of chemical reactions and cool fuel through physical action.
Fire retardants are available as fire retardant gels, foams, and powder to be used with water. They sometimes come as sprays or coatings to be applied to objects. The specific ingredients of fire retardant vary depending on the type and intended application.
There are many types of fire retardants, each with its own formulations and purpose. Here are the most common fire retardants and their composition.
Nitrogen-Based Fire Retardants
Fire retardants made from nitrogen incorporate nitrogen compounds which help reduce the flammability of materials. Common examples of nitrogen-based fire retardants include guanidine phosphate, melamine cyanurate, and melamine.
Phosphorus–Based Fire Retardants
Phosphorus-based fire retardants are designed to prevent combustion. Common ingredients in phosphorus-based fire retardants include ammonium polyphosphate, and phosphorus-based esters like triphenyl phosphate.
Halogenated Fire Retardants
Halogenated fire retardants are composed of halogen elements such as chlorine or bromine. They function by reducing the flammability of materials and retarding the spread of fire. This is often achieved by producing halogen radicals when exposed to high temperatures, which interact with combustion radicals and interrupt the chemical reactions that sustain fire.
Tetrabromobisphenol A (TBBPA), polybrominated Diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD) are commonly used.
Inorganic Fire Retardants
Inorganic fire retardants are added to products to reduce flammability and slow down the spread of fire. Unlike carbon-based fire retardants, inorganic fire retardants are composed of minerals and non-carbon-based compounds. They work by forming a protective layer, producing water vapor, or diluting the concentration of flammable gasses.
Inorganic fire retardants include phosphate-based retardants that contain various compounds like diammonium phosphate and ammonium polyphosphate. Halogen-based fire retardants include chlorine and bromine compounds that work by releasing halogen radicals when exposed to heat.
Hydroxide-based flame retardants include magnesium hydroxide and aluminium hydroxide, which work by releasing water vapor when heated. Borate-based fire retardants include zinc borate, which functions as a flame retardant by releasing water molecules and creating a protective glass-like layer once heated.
Zinc borate also serves as an anti-corrosion agent in polymer and coating applications. This substance prevents the degradation of materials or products caused by chemicals, moisture, and environmental elements, extending the lifespan of products.
Zinc borate is a preferred option for textiles, wood preservatives, and building materials thanks to its fungicidal and mold-inhibiting properties.
Although fire retardants offer several benefits when incorporated into certain materials, there are potential health effects associated with these substances. These may include reproductive toxicity, thyroid disruption, cancer, and immunotoxicity.
Contact Bisley International
At Bisley International, we supply a wide range of flame retardants, including zinc borate. Contact us today to learn more about our fire retardants and place your order.