All those plastic bits and pieces in your car’s dashboard, all those metres of cabling in your office building, all those foam cushions in your comfy chair, and every bit of protective workwear on a factory floor-they all contain flame retardants. Those are the chemicals that hold the line between conventional combustible stuff and a devastating inferno, and I can’t think of any safety engineer more essential.
This guide provides insights into what flame retardants are, how they work, types of flame retardants, the applications of Flame Retardants in different industries, and a huge regulatory decision that will change the game for the industry. This guide will be useful to anyone interested in polymer technology or working as a polymer engineer or compliance officer in compliance and will provide enough of the right information to make their work easier.
What Are Flame Retardants?
Flame retardants are chemical formulations that are added or applied to materials (mainly plastics, textiles, foams, and coatings) to increase their fire resistance and slow the growth of a fire. Flame retardants are not fireproofing chemicals; they delay the time to the start of a fire, slow the spread of flames and provide more time for occupants to escape.
There are four principles that flame retardants can operate by.
- Gas phase radical trap: FR liberates active species (phosphorus or halogen radicals) that break the chain reaction in a flame by scavenging the highly reactive H and OH radicals that are actually maintaining the burning condition.
- Condensed-phase char production: FR supports the creation of a carbonaceous char layer on the surface of the material, serving as a barrier to prevent the flame from contacting unburned material.
- Endothermic cooling: Certain FRs (such as metal hydroxides) undergo endothermic decomposition, which helps to cool the fire by absorbing heat and expanding water vapor while also reducing the concentration of flammable gases.
- Intumescence: The formulation of the FR system makes the material foam, forming an insulating, expanded char which protects the substrate from heat and flame; this is the mechanism used by advanced phosphorus-nitrogen systems such as PPM Triazine.
The Halogenated vs. Halogen-Free Debate
The Conversation at the Heart of Flame Retardants Today. Brominated and chlorinated flame retardants were the industry standard for decades, owing to their remarkably high performance at extremely low loadings. However, their known impacts on the environment and human health have prompted a worldwide regulatory reaction:
EU RoHS Directive: Limits certain brominated FRs (PBBs, PBDEs) in electrical and electronic devices.
- REACH regulation in the European Union: The following halogenated flame retardants are classified as SVHCs, or as restricted substances in Annex XVII.
- Stockholm Convention: Some, for example, brominated flame retardants, are subject to specific control under the Stockholm Convention on POPs, which is a list of chemicals that have to be removed or restricted.
- OEM demands: All globally leading car and electronics manufacturers (BMW, Apple, Samsung, and Volvo) are now demanding completely halogen-free materials for their procurement.
- Halogen-free flame retardant consumption is on the rise indeed. The real question for the majority of users is not “Should I go halogen-free?” but “Which one?”
Key Applications of Flame Retardants
Electronics and Electrical
RCBs: Laminates, cable insulation, and connectors; enclosures for batteries; enclosures for phones and notebooks. Many examples of the impact of RoHS migration with 100% of consumer electronics made from halogen-free FRs. The growth of EVs will lead to a nuclear-level increase in demand for battery pack fire safety.
Construction and Building
Building insulation-EPS, XPS, PU cladding boards, roofing membranes, pipe insulation, building insulation, and fire ratings in building codes (Euroclass and ASTM E84 and BS 476-are all about flame performance.
Automotive and Transport
Interior, under-hood or under-body traction mats; foams for seats, headliners; EV battery encapsulation, wire harness cover and pads and spools; interior car components such as sidewalls, armrests and headliner, ceiling pads, pet barriers, inside and outside shields, light strips for doors and dashboards.
Textiles and Furnishings
Protective clothing, military uniforms, plane seats, hotel curtains, Mattress ticking, upholstery. The use of FR is driven by standards such as EN 11612 (protective clothing), BS 5852 (furniture), and FAR 25.853 (aircraft interiors).
Railway and Aerospace
Cladding materials, flooring, cable ducting, and seat materials: EN 45545 (railway fire safety) and FAR 25.853 are among the most rigorous flame, smoke, and toxicity (FST) standards in any industry.
PPM Triazine: A Next-Generation Halogen-Free Flame Retardant
There are several halogen-free alternatives, one of which is the technologically advanced PPM Triazine (CAS 93058-67-4), a polymeric nitrogen synergist formulated by MCA Technologies, Switzerland, which acts as a synergist in conjunction with ammonium polyphosphate (APP) to form a highly effective intumescent FR system.
What distinguishes it from other classes of conventional nitrogen synergists (melamine, simple triazines): 1. The large molecular weight of the PPM triazine polyamide matrix. This polymeric structure prevents 3 persistent problems typical for other small-molecule agents: sublimation in high-temperature processing, toxic ammonia release from self-condensation, mould deposits or plate-out on finished parts.
Case Study: Automotive Interior Manufacturer Transitions to Halogen-Free Flame Retardants
Background: A leading automotive supplier of polypropylene interior parts for a European OEM had been ordered to change its plastic materials from brominated fire retardants to halogen-free options in 18 months in order to comply with the changes in the OEM’s new material requirements for parts as well as with the changes in EU regulations.
The Problem: The present brominated FR system gave UL 94 V0 at 12% loading with acceptable retention of mechanical properties. First attempts at using aluminium trihydroxide (ATH) gave ~55% loading necessary for near V0, but this reduced impact strength by 60%, making the parts very brittle for crash safety performance. A melamine nitrogen system resulted in processing difficulties, with ammonia odour, surface residues, and mould fouling.
The Solution: The engineers opted to go with an intumescent system of 75% ammonium polyphosphate + 25% PPM triazine HF at 23% total loading. The polymeric nature of PPM triazine addressed the sublimation and ammonia issues that were brought on by smaller-molecule systems.
Key Takeaway: PPM Triazine provided V0, halogen-free performance at less than half of the ATH loading, while maintaining the mechanical properties critical to automotive crash performance. Total cost increase was circa 8-10% of the addition to the FR line item, although this was mitigated by no retooling of the application to maintain the existing cycle time and avoid the mechanical failures seen with the alternative fire performance.
Factors to Consider Before Buying Flame Retardants
- Target: What fire safety standard does your part need to comply with (UL 94, LOI, EN 45545, FAR 25.853, etc.)? Find the UL/fire safety standard you need to comply with, go back to the FR system.
- Halogen-free requirement: Where halogen-free is a customer or end-market requirement, it can instantly limit you to phosphorus-, nitrogen-, metal hydroxide-, or silicon-based systems.
- Mechanical property impact: Increased FR loading results in a decrease in impact, tensile, and elongation performance. Select systems that can meet the desired fire rating at the lowest loading to minimise these losses.
- Processing compatibility: The FR should meet your processing temperature, shear, and molding/extrusion parameters for the volume and rate required for the specific polymer without exhibiting degradation or discolouration, or gumming the equipment.
- Smoke and Toxicity: In-box applications (defense, aerospace, electronics), the volume of smoke and toxic gas emission can be equally as important as the flame retardance of the plastic.
- Supplier insight: select a supplier that provides far more than the FR additive-they should be able to support you with formulation guidance, technical expertise, and regulatory compliance.
Sourcing Flame Retardants: PPM Triazine from Anar Chemicals
Anar Chemicals LLP holds the sole license to manufacture and sell PPM Triazine from Anar Chemicals, Switzerland, under the brand name MCA Technologies as PPM Triazine for the Indian market. PPM Triazine is supplied in India by Anar Mcat Advanced Electronic Chemicals Pvt. Ltd., an Indian joint venture company, which is a 50/50 partnership between Anar Chemicals LLP and MCA Technologies GmbH.
Frequently Asked Questions About Flame Retardants
Q: What are flame retardants?
Flame retardants are chemical formulations that are incorporated into the structure of a material (Plastics, Textiles, Foams, Coatings, Building & Construction Products) to prevent or delay the spread of fire. They achieve this by disrupting the chemical reaction (by trapping radicals in the gas phase, forming a char in the condensed phase, or cooling through endothermic reactions or a mixture of both).
Q: What is the difference between halogenated and halogen-free flame retardants?
Halogenated flame retardants contain bromine or chlorine chemistry and form a chemical bond with combustion radicals, the propagation phase of the fire, in the gas phase. Halogenated fire retardants provide high levels of flame resistance at low loading levels but give off toxic smoke, corrosive gases, and very high levels of toxic environmental pollutants when exposed to fire.
Q: Why is the industry shifting to halogen-free flame retardants?
The trend is driven by tougher rules and regulations (EU RoHS, REACH, WEEE); the toxicity of smoke during building and vehicle fires; the durability of halogenated compounds in the ecosystem; and OEM requirements for supply chains to use HF materials. The trend is particularly strong in electronics, automotive, and building.
Q: What is PPM Triazine and how does it work?
PPM Triazine (CAS 93058-67-4) is an MCA Technologies patented polymeric nitrogen synergist. It is compatible with ammonium polyphosphate (APP), producing an intumescent fire retardant system. As the polyurethanes and polyesters are exposed to high temperatures, the material foams, crosslinks, and carbonizes to produce an extremely dense “fire shield” which is multi-functional, preventing the ingress of heat, lowering oxygen levels, and preventing the polymer from dripping.
Q: What UL 94 ratings can be achieved with flame retardants?
Rating depends on the FR system and loading level. Metal hydroxide systems for 20-25% loading at PPM Triazine+APP give UL 94 V0 in polypropylene at 1.6 mm. For the same rating, a metal hydroxide system would need 50-60% loading, which could lower mechanical properties. In general, halogenated systems get V0 at 10-20% loading.
Q: Which industries use Flame Retardants most?
These include electronics (PCBs, cables, casings), building and construction (insulation, cladding, structural and architectural coatings), automotive (interior parts, EV battery packs, wiring looms), textiles (protective clothing, interior furnishings), and train and aerospace (interior panels, seats). All industries in which fire safety requirements are in place.
Q: Where can I buy halogen-free Flame Retardants in India?
Anar Chemicals LLP (anarchem.com) is the sole licensee of MCA Technologies, Switzerland, for manufacturing and marketing PPM Triazine, the more sustainable solution for halogen free flame retardant based on phosphogen nitrogen technology. They are ISO 9001:2015, ISO 14001:2015 & ISO 45001:2018 certified, with over 40 years of experience.