Silicon Flame Retardant

Silicon flame retardant is a new type of halogen-free flame retardant and a carbon-forming smoke suppressant, which imparts excellent flame retardant and smoke suppression properties to the polymer. Alfa Chemistry offers a range of high-quality silicone-based flame retardants to help you make progress in the field of flame retardant materials.

Classification

Silicon-based flame retardants are divided into two categories: silicone systems and inorganic silicon system.

• Silicone system mainly includes polysiloxanes, such as silicone oil, silicone rubber, various siloxane copolymers, and silicone resins. Among them, organopolysiloxane is the fastest developing.
• Inorganic silicon system mainly includes silicate (such as montmorillonite), silica gel, talc and so on.

Advantages

• Excellent flame retardant and smoke suppression properties
• High flame retardant efficiency
• Low smoke
• Non-toxic
• Halogen free
• No droplet
• Environmentally friendly and will not cause environmental pollution
• Can improve the processability and mechanical strength of the polymer

Flame Retardant Mechanism

Silicone flame retardants achieve their flame retardant effect by generating a cracked carbon layer and improving the oxidation resistance of the carbon layer. After adding silicone flame retardant to the polymer material, the silicone flame retardant will mostly migrate to the surface of the material to form a dense and stable carbon layer containing silicon (the main component SiO₂). This silicon-containing carbon layer not only prevents the escape of combustible substances decomposed by combustion, but also acts as heat insulation and oxygen insulation, preventing the thermal decomposition of polymer materials, and achieving the purpose of flame retardancy, low smoke and low toxicity.

The flame retardant effect of inorganic silicon-based flame retardants belongs to the condensed phase flame retardant mechanism, which is generally considered to be achieved by the barrier and shielding effect of the amorphous silicon or silicide protective layer formed during combustion.

In addition, silicon-based flame retardants will also undergo thermal decomposition when heated. This process needs to absorb a lot of heat, which can slow down or stop the temperature rise of the flame retardant materials.

The flame retardant mechanism of silicone rubber (SR) [1]

Research Information

Silicone Flame Retardant Adhesive

Wen Wang et al. developed a flame retardant adhesive and investigated the shear strength and fire resistance of this silicone-based (SI) plywood (SI/plywood). In this work, a silicon-based elastomer of vinyl-silane treated aluminum hydroxide was used instead of conventional polyurethane-based adhesives. The results show that SI/plywood has higher burn-through resistance and thermal barrier efficiency, as well as lower flame spread and heat release rate, exhibits excellent fire resistance and responsiveness to fire, and improves fire resistance. [1]

Images of the samples during LIFT experiments and the sample residues. (a) PU/plywood tested for 5 min; (b) SI/plywood tested for 5 min; (c) SI/plywood tested for 10 min. [1]

References

1. Chenyang Zhang, et al. (2019). "Preparation of a novel type of flame retardant diatomite and its application in silicone rubber composites," Advanced Powder Technology 30(8), 1567-1575.
2. Wen Wang, et al. (2018). "A novel application of silicone-based flame-retardant adhesive in plywood," Construction and Building Materials 189, 448-459.