What is The Mechanism of Zinc Borate Fire Retardant?

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As an avid reader interested in the latest fire safety technologies, you may wonder about the mechanisms behind modern flame retardants like zinc borate. In this article, we’ll delve into the mechanisms behind zinc borate’s fire retardancy, its synergistic effects with other compounds, and its ability to suppress smoke and reduce heat release.

How Zinc Borate Works as a Fire Retardant

Zinc borate (ZB) is an inorganic compound that acts as a flame retardant by releasing water and forming a protective layer of boron oxide on the surface of combustible materials. When exposed to heat, ZB decomposes endothermically, absorbing energy from the surroundings. This decomposition produces water vapor and boric acid, which then dehydrates to form a molten boron oxide layer.

The water released by ZB dilutes combustible gasses and lowers the flame’s temperature. The boron oxide layer acts as a protective barrier, preventing oxygen from reaching the fuel and suppressing smoke emissions.

ZB can achieve fire retardation independently, but it is often used with ammonium polyphosphate, magnesium hydroxide, and other flame retardant additives to improve performance through a synergistic effect.

Why Zinc Borate Is a Preferred Fire Retardant Additive

Zinc borate is an inorganic compound commonly used as a fire retardant additive due to several advantages over other options.

Thermal Stability

Unlike ammonium polyphosphate and magnesium hydroxide, zinc borate remains stable at high temperatures without decomposing. This allows zinc borate to provide fire protection even when a material is exposed to heat over a long duration.


Zinc borate is a halogen-free flame retardant, meaning it does not produce toxic gasses when exposed to fire. This is an important safety benefit compared to halogenated flame retardants.

Synergistic Effect

Zinc borate synergizes when combined with other flame retardants like aluminum trihydrate. Together, these compounds reduce heat release and flame spread more effectively. This synergistic effect allows lower concentrations of each compound to be used.

Smoke Suppression

Zinc borate inhibits the formation of smoke by preventing the release of volatile organic compounds during combustion. By limiting smoke production, zinc borate improves visibility and safety in the event of a fire.

Order Quality Zinc Borate From Bisley International

To obtain high-quality zinc borate as a flame retardant, purchase raw materials from a reputable supplier like Bisley International. We are an international distributor of industrial chemicals with locations across Australia, New Zealand, Asia, the Middle East, and North America.

We have zinc borate products that are curated to maximum fire retardancy. Contact us today to inquire about our Zinc Borate products and place an order.