As someone who designs plastics, industrially engineers automotive parts, and develops electronics and textiles, you don’t have to be an expert to realize the regulatory pressing issue of flame retardants has been continuing to strengthen for the past 10 years. And the feedback we keep hearing in the marketplace is very clear: No more halogenated flame retardants; we want Halogen Free Flame Retardant (HFFR), or die.
Certainly, it is not as easy as just replacing one additive for a new one. You have to be familiar with the chemistry, the performance compromises, regulatory constraints, and the various product options available. We will try to address all of those questions-particularly when it comes to PPM Triazine, a phosphorus-nitrogen-based HFFR that represents the cutting edge of intumescent flame retardant technology.
What Is a Halogen Free Flame Retardant?
A Halogen Free Flame Retardant (FR) is a fire safety additive that provides flame resistance without the inclusion of any halogen elements (chlorine, bromine, fluorine, or iodine). Flammability safety additives, which incorporate halogenated flame retardants, including chlorinated paraffins, brominated diphenyl ethers, etc., are very efficient at reducing the risk of ignition; however, they have some major disadvantages, as during combustion they give off thick carcinogenic smoke that contains damaging hydrogen halides, dioxins, and furans.
Halogen-free options utilize different chemistries to provide fire retardant qualities. The most commercially successful has been P-N (or phosphorus-nitrogen) synergism that works by intumescence: when subjected to heat or flame the foam burns, foams and creates a thick insulating skin of char, or carbon, on the surface of the material. This char provides a barrier to heat and oxygen, and prevents droplets of molten polymer from forming.
The outcome: Excellent flame retardancy and significantly reduced toxic smoke, no halogenated by-products, safe in accordance with today’s stringent environmental legislation such as REACH, RoHS, and WEEE.
Why the Industry Is Moving to Halogen Free
- Regulations: The EU RoHS Directive restricts some halogenated compounds in electronics. REACH has pre-registrations and regulatory control processes for chemical substances, including FRs, with some halogenated compounds already on the SVHC Candidate List. Halogen-free regulation is increasingly demanded by OEM customers at the supply chain level.
- Toxic smoke issues: In building fires, smoke inhalation remains the primary cause of death-and halogenated flame retardants are a major contributor to smoke toxicity. HFFR systems generate much less toxic and corrosive smoke, increasing survivability in confined areas.
- Bioaccumulation in the environment: Some halogenated FRs are accumulating in the environment as a contaminant and thereby are inherently toxic. HFFRs are not at all.
- Recycling: Halogen-free plastics are better recyclable. It is possible that as flammable products, halogenated products will produce dangerous gases during thermal recycling at the end of life.
PPM Triazine: A Closer Look at Advanced P-N Flame Retardation
PPM Triazine (CAS 93058-67-4) shows higher technical levels than all of the phosphorus-N-based HFFR systems in the market: PPM Triazine has been invented by MCA Technologies, a Swiss company. It is a patent on a new polymeric nitrogen synergist, which can be transformed into an excellent intumescent flame retardant system with APP.
Why it’s different from regular nitrogen synergists (melamine, triazine derivatives) like:
- Large molecular weight: Polymeric, high molecular weight PPM triazine shows NO sublimation during high-temperature processing, NO toxic ammonia release from self-condensation, and NO mould deposits and plate-out when compared to lower molecular weight nitrogen synergists.
- Empirical Performance: 75% APP, 25% PPM Triazine HF with 20-25% total loading will give UL 94 V0 in polypropylene at 1.6 mm, in addition to LOI in excess of 30%.
- Flexibility: It is compatible with polypropylenes, poly-urethanes, rigid and flexible polyurethane foams, epoxy resins, unsaturated polyester resins, and thermoplastic elastomers.
- Low Smoke, Low Toxicity: The process results in low smoke densities and generally the reduction of toxic fumes by thousands of times when compared with halogenated systems and some other competing HFFR technologies.
Applications of Halogen Free Flame Retardants
Electronics and Electrical
PCB laminates, cable insulation, connectors, housings, and enclosures. RoHS compliance is driving near-universal adoption of HFFR in consumer electronics.
Automotive
Interior trim, dashboard components, under-hood parts, battery housings (especially critical for EV battery packs), and wire harnesses. OEMs increasingly specify halogen-free materials.
Construction and Building
Insulation boards, cladding panels, pipe insulation and structural coatings. European and Asian building regulations are becoming more and more concerned with low-smoke, halogen-free products.
Railway and Aerospace
Interior panels, seat upholstery, cable ducting, and flooring. The most common industry standards requiring use of HFFR include EN 45545 (railway) and FAR 25.853 (aerospace).
Textiles
Protective workwear, upholstery, curtains, and mattress ticking. Phosphorus-nitrogen HFFR treatments can achieve self-extinguishing performance with durability through multiple wash cycles.
Case Study: Achieving UL 94 V0 in a Polypropylene Automotive Component with PPM Triazine
Background: An automotive Tier-1 manufacturer, a large European OEM supplying interior trim components to the OEM, needed to convert all PP products from their existing brominated flame retardant system to a halogen-free system in order to comply with the OEM’s material specification. The goal was UL 94 V0 1.6 mm with no dripping together with OEM internal requirements on low smoke emission.
The Problem: First tests with aluminum hydroxide (ATH) in HFFR applications needed loadings well above 55% to get V0 performance, which, in turn, compromised the mechanical properties of the PP compound to the extent that impact strength was compromised by 60% and parts were too brittle to pass the OEM crash safety test. The melamine polyphosphate system also failed due to ammonia odor during processing and surface deposits on the molded parts.
The Solution: The fabric was impregnated with the impregnation intumescent system with the following weight application rates: 75% Ammonium Polyphosphate (APP) + 25% PPM Triazine HF at 23% total loading. The polymeric structure of PPM triazine in this intumescent blend prevented both sublimation and ammonia problems that occurred with the shorter molecule synergists.
Key Takeaway: When loaded at less than half the ATH loading level, the PPM triazine-based intumescent system provided excellent flame retardant performance without compromising the mechanical properties required by the automotive application. This example is typical of the rising trend towards using phosphorus-nitrogen intumescent systems as the preferred HFFR technology for engineering plastics.
Sourcing Halogen Free Flame Retardants: PPM Triazine from Anar Chemicals
Anar Chemicals LLP is licensed by MCA Technologies, Switzerland, as their sole manufacturer and marketer of PPM triazine in India. The product is marketed in India through Anar Mcat Advanced Electronic Chemicals Pvt. Ltd.
Anar Mcat is a 50-50 JV between Anar Chemicals LLP & MCA Technologies GmbH.
Anar Chemicals LLP is a 44-year-old manufacturer of chemicals and the first Indian company to be certified for ISO 9001:2015, ISO 14001:2015 & ISO 45001:2018 Anar Mcat offers technical support in formulation development and assures timely & quality assured supply of PPM Triazine. Please visit the PPM Triazine product page or contact for technical queries or bulk pricing.
Frequently Asked Questions About Halogen Free Flame Retardant
Q: What is a halogen-free flame retardant?
A halogen free flame retardant (HFFR) is a fire-retardant additive that is free of any chlorine, bromine, fluorine, or iodine. Instead, they rely on other chemistries to provide flame-resistant materials such as phosphorus-nitrogen synergism. During combustion, HFFR’s generate a far lower amount of toxic smoke and corrosive gases than their halogenated brethren.
Q: What is PPM Triazine?
Triazine (CAS 93058-67-4) Innovative PPM Triazine (polymer) is a unique compound and halogen-free nitrogen synergist from MCA Technologies, Switzerland. Intumescent flame retardant system consisting of PPM triazine with ammonium polyphosphate (APP). In a fire environment the system undergoes foaming, cross-linking, and forming a solid protective char layer, which acts as a fire shield.
Q: How does phosphorus-nitrogen synergism work in flame retardants?
The phosphorus-based materials generate phosphoric acid when heated, which catalyzes the formation of a char layer on the surface of the substrate. The nitrogen-based materials generate inert gases, which dilute the combustible gases (intumescence) and form foam (intumescence). These two combine to produce a dense, insulating barrier that shields the material from heat transfer, limits oxygen transfer and stops the molten polymer from dripping.
Q: What are the advantages of HFFR versus halogenated flame retardants?
Advantages of HFFRs vastly reduced smoke toxicity, much less corrosive gases generated, offer greatly enhanced survival advantages, do not contain or produce dioxins or furans, meet all current and future environmental regs (RoHS, REACH, WEEE) and are recyclable. The only issue is that, in some cases, higher loadings of HFFR material might be required than with other halogenated systems.
Q: What is the UL 94 rating of PPM Triazine?
Polybutylene combustion drop-in: Most products achieve UL 94 V0 in polypropylene 1.6 mm with typical total loadings of 20-25% as a 75/25 mix of ammonium polyphosphate & PPM triazine HF and over 30% LOI. They will also work in polyurethane foam, unsaturated polyester resins, and epoxy resins with comparable ratings.
Q: Which industries require halogen-free flame retardants?
Primary sectors are electronics and electrical (electrical cables, PCBs, and connectors), automotive (inside and underbonnet parts), construction (cladding and insulation), railway and aerospace (seating and interior panels), and textiles (cushion covers, curtains, and workwear). The European Union (EU) has traditionally had the highest level of regulation and is where the most significant shifts towards HFFRs have occurred (RoHS, REACH).
Q: How much is the halogen-free flame retardant price in India?
Anar Chemicals LLP is the sole licensee for Indian production & marketing of PPM Triazine from MCA Technologies Switzerland, through their dedicated JVC-Anar Mcat Advanced Electronic Chemicals Pvt. Ltd., and is ISO 9001:2015 & 2015, ISO 14001:2015 & ISO 45001:2018 certified. Anar Chemicals LLP is in the business of manufacturing and marketing 5 unique polymers & chemicals.