April 29, 2025

Flame-retardant additives: what they are and why they really matter

From halogenated compounds to intumescent systems, an overview of the ingredients that make polymers safe, balancing performance, regulations, and sustainability.
 

Why is flame retardancy crucial in plastics?

Polymeric materials exposed to intense heat can ignite and sustain self-combustion, releasing significant thermal energy. This process not only maintains the flame but also promotes the spread of fire to adjacent materials.

To counteract this, flame-retardant additives are used—substances that alter the polymer’s combustion behavior. Their function is to interrupt the thermo-oxidation process through chemical or physical mechanisms that block the reaction or prevent contact between oxygen and the molten polymer.

Types of flame-retardant additives: how they work

Intrinsically flame-resistant polymers are rare.

PEEK and PPS, for instance, have a chemical structure that limits flammability. However, most polymers require specific additives to meet industry standards, such as UL94 or the Glow-Wire Test for household appliances.
Common solutions include:

• Halogenated additives, like bromine-based compounds. These release free radicals that block oxidation reactions in the flame. Effective, but subject to restrictions for environmental and health reasons.
• Physical barrier additives, like red phosphorus, which forms an insulating char layer, or intumescent systems that create an expanded solid foam to shield underlying materials from heat.
• Synergists that enhance the main additive’s effectiveness—e.g., metal oxides, nitrogen compounds, and other co-additives. These too are under international scrutiny for environmental and safety concerns.

Toward greener solutions: halogen-free and red phosphorus-free additives

The industry is shifting toward safer formulations aligned with regulations like REACH and RoHS.
Halogen-free (HFFR) and red phosphorus-free solutions are spreading, offering reliable fire protection with reduced ecotoxicological impact. However, these alternatives may present challenges such as:

• Lower thermal stability
• Compromised mechanical properties
• Reduced compatibility with some engineering plastics

Conclusion: choosing the right additive with awareness

Choosing the right flame-retardant additive requires a strategic balance between fire performance, polymer matrix integration, regulatory compliance, and environmental responsibility.

In a market increasingly focused on safety and sustainability, innovative, efficient, and green additive solutions provide a real competitive edge.

At LATI, we can support you with this too. Submit your request here.