Antimony Flame Retardant

Antimony Flame Retardant

Antimony flame retardants are a kind of additive flame retardants. When used in combination with halogen-based flame retardants, the performance of the flame retardants can be greatly improved. Alfa Chemistry can provide customers with high-quality antimony flame retardant products with various detailed requirements through various production processes.

Typical Products

Antimony trioxide (Sb2O3), colloidal antimony pentoxide (Sb2O5) and sodium antimonate (Na3SbO4) are the main products of antimony flame retardants. Among them, Sb2O3, a typical additive inorganic flame retardant, is widely used.

There are many different grades, such as ordinary grade, superfine grade, high purity white grade, etc. The particle size and chemical reactivity of antimony flame retardants are determined by processing conditions.

Flame Retardant Mechanism

Sb2O3 first melts during the combustion period, with a melting point of 665°C. A protective film is formed on the surface of the material to isolate the air, and the combustion temperature is reduced through an internal endothermic reaction. At high temperature, Sb2O3 is oxidized, diluting the oxygen concentration in the air, thereby achieving flame retardancy effect.

Flame-retardant mechanism of antimony flame retardant in PP-based compositesFlame-retardant mechanism of antimony flame retardant in PP-based composites [1]


Sb2O3 is mainly used for the flame retardant of plastic products, synthetic resins and textile fabrics, and can also be used as a flame retardant for rubber, wood and fibers.

Halogen-free antimony compounds have little flame retardant effect on their own, but when used with halogen-containing organic compounds, they form a very effective antimony/halogen flame retardant synergistic system.

Sb2O3 Toxicity

Regarding its own toxicity, a large number of studies have shown that antimony-containing flame retardants are not very toxic or cause cancer. The Sb2O3 toxicity test results are shown in the table below.

Experimental MethodTest Results
Severe inhalation toxicity (tested with rats)LD50 > 34.6g/kg
Severe contact skin toxicity (tested with rats)LD50 > 20.0g/kg
Eye irritation (stimulated with rats) without rinsing eyes; rinsing eyes for four secondsVery severe if eyes are not rinsed; relatively severe if eyes are rinsed after 4 s of contact.
One-time skin irritation (tested with rats)Little stimulation
Skin allergy (test on human)No allergies found
One-time skin test (on humans)No irritants found

In addition, the antimony-bromine flame retardant has the problem of a large amount of smoke. The current effective suppression method is the antimony-based composite flame retardant or the ultra-fine treatment of antimony oxide.

Research Information

Sb2O3 For Consumer Electronics Applications

Electronic equipment components composed of polymer materials are easily ignited due to their vulnerability to flames. In this study, the researchers produced flame-retardant nanocomposites by enhancing halogen-free inorganic additives for use in components of electronic devices. The results show that magnesite/hydromagnesite and Sb2O3 have a synergistic effect, effectively reducing the flammability of ABS composites to UL94/V-0 rating. [2]

UL 94-V testing results of ABS and ABS compositesUL 94-V testing results of ABS and ABS composites [2]

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  1. Jianlin Xu, et al. (2018). "Influence of montmorillonite on the properties of halogen–antimony flame retardant polypropylene composites," Polymer Composites 40(5), 1930-1938.
  2. Metin Yurddaskal, et al. (2018). "Synergetic effect of antimony trioxide on the flame retardant and mechanical properties of polymer composites for consumer electronics applications," Journal of Materials Science: Materials in Electronics 29, 4557–4563.
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