New flame retardants and applications trend towards PIN flame retardants
Tobias Moss, Budenheim (pinfa member), sees PIN flame retardant development continuing to move towards achieving higher fire safety requirements whilst maintaining material performance and achieving sustainability objectives: environmentally friendly (if possible not Classified), low carbon footprint, recyclable. A key performance parameter in many applications is CTI (comparative tracking index), which measures the resistance to travel of current across the surface of a material, and so the risk of short-circuiting or current leakage. CTI is thus a priority in formulating plastics for electrical or electronics applications, especially with high voltage and miniaturisation, including electric vehicles. PIN flame retardants do not release halogen acids, and so can achieve CTI performance around twice as high as halogenated FRs. Budenheim’s PIN FR synergists can increase CTI by +20% to +50% in e.g. PBT. Development of new flame retardant solutions requires close cooperation between end users (OEMs), compounders and FR manufacturers, in order minimise risks for all parties. For example, with Ecobat Budenheim have developed a PIN FR polypropylene produced 100% from post-consumer batteries which achieves UL 94 V-0 (3 mm) with 20% glass fibre.
Marie-Raphaël Morvillier. Adeka (pinfa member) started developing flame retardant solutions some 20 years ago, in response to demand for non-halogenated polymer formulations, with the aims of ensuring chemical safety, low carbon footprint and sustainable supply chain. Adeka’s intumescent PIN flame retardants ensure long-lasting flame retardancy for durable materials and low corrosion in processing (no acid release). Adeka is now developing PIN FR solutions for recycling, including for post-consumer polypropylene (from bottles) and for plastics recycling from end-of-life vehicles. After a broad market survey on recyclates from different waste sources, such as end-of-life electrical equipment, sorted household waste and vehicles globally, Adeka identified representative commercial streams to be upgraded to flame retardant plastics. In collaboration with Galloo plastics (see below), Adeka’s PIN FRs were tested in Galloo’s commercially recovered polypropylene from end-of-life vehicles (95% PP) and UL 94 V-0 (1.6 mm) was achieved with 30% PIN FR loading, with mechanical properties similar to flame retarded virgin PP. The same UL 94 was achieved in post-consumer polypropylene (94% PP; 6% PE, plus low levels of mineral filler and antioxidant), and again mechanical performance was comparable to FR virgin PP.
Micaela Lorenzi, Green Chemicals (pinfa member), underlined the essential role of flame retardants in plastics, because, in case of fire, they increase time for escape, showing a video of fire spread in expanded polystyrene with and without flame retardants. Green Chemicals offer PIN flame retardants because these avoid the health and toxicity problems of halogenated chemicals, they can be produced with European raw materials, they have less negative impacts on UV stability of polymers and on recycling (no release of brominated radicals). PIN FRs avoid the supply and price dependency on China of ATO (antimony trioxide), a necessary synergist for most halogenated FR packages. Green Chemicals offers PIN FR solutions as compacted powders, with PIN FRs, synergists and stabilisers blended into a few % of polymer, ready for processing (optimal flow and mixing, low dusting), for e.g. polypropylene, polyamides, polycarbonate, polyurethanes. Specific solutions for certain polymers include: organic, silicon or boron compounds which can reduce dripping in polyamides (without PFAS anti-drip); a cyclic phosphonate with potassium sulphonate for polycarbonate, achieving UL 94 V-0 (< 2 mm) at 5-7 % loading. Some reactive PIN FR solutions were presented, reducing the required FR loading and limiting risks of leaching or blooming, but further development is needed for different polymers..
Muhammad Aslam, Momentive Performance Materials, presented silicone compounds as synergist enablers for 100% non-halogen fire safety solutions, with PIN flame retardants and without PFAS drip-suppressant. Silicones offer transparency / no coloration, low VOC (volatile organic carbon) emissions, can improve material performance (elongation at break, avoid low temperature brittleness, moisture resistance, UV stability, electrical insulation) and improve processing. Momentive’s liquid silicone fluid PIN FR synergists are compatible with engineering polymers, and at 1 – 4 % dosing improve char formation for PIN FRs, reduce dripping and smoke emission. Examples of formulations in polycarbonate and polyamide were presented, achieving UL 94- V0 or -V1 (1.6 mm) in 100% non-halogen formulations with total PIN FR+ synergist loading of 10 – 15 %.
Interview: Momentive Performance Materials
Muhammad Aslam. Momentive (part of KCC Group) is a global leader in silicone and silane technologies, with a strong corporate commitment to sustainability. Momentive, headquartered in the USA, has 5 000 staff worldwide and a 3 billion €/year turnover. Momentive suppliers specialist silicones for use in polymers for processing aids, impact modifiers, flame retardancy (char generation) and anti-drip. Momentive’s specific silicones, at 1 – 5 % loadings, can replace PTFE (PFAS) as polymer processing aids and as anti-drip agents, and also improve material performance (processing, elongation at break, ductility, low temperature impact resistance). Selection of targeted functional groups on silicones enables tailoring of a wide range of products for specific polymers and applications, reactive or additive, case-by-case according to customer needs, to maximise synergies with the base polymer and with other additives. Two component products (silonol, silicone) can optimise char formation, anti-drip and material performance functionalities. They are generally used with a primary PIN flame retardant, often phosphorus based, enabling optimisation of total FR loading, and offering solutions to customers looking to move away from PFAS anti-drip additives and to implement sustainable PIN flame retardants.
Ronald Wilmer, Oceanchem. The company started in 1953 and is one of major bromine flame retardant producers in China, now also focussing on Non Halogen systems. The company is now developing non-halogenated flame retardant solutions to respond to the market and towards the need of new PIN FRs to replace brominated FRs and to prove that PIN FRs enable low-smoke in many applications. Oceanchem now offers intumescent PIN FRs for polypropylene and polyethylene for automotive and other electrical applications. The company’s PIN FR for glass fibre polypropylene battery casings is used in most Chinese and Korean EVs imported into Europe. Oceanchem is currently furthering work on PIN FRs to address the challenges of discolouration with ageing, anti-drip (non PFAS alternatives to TPFE), improving processing and increasing processing temperature windows, and price.
Interview: INTO Chemicals
Nick Van De Pol. Into Chemicals offers performance FR formulations, combining different FRs, synergists and additives, adapted to customer needs and applications, including for plastics, wood, papers (used in insulating panels), recycled fibres used for insulation. The company can provide solutions to materials fire safety and performance demands where one flame retardant alone cannot. Into Chemicals sees the trend to move away from halogenated flame retardants. Formulation challenges include increasing the effectiveness and lowering loadings for PIN FRs, the question of free melamine in melamine compound FRs and alternatives to melamine as a blowing agent and PIN FRs to achieve UL 94 V-0 low smoke (“b” classes) for building materials.
Masayuki Okoshi, Japan Society of Flame Retardant Materials, summarised developments in flame retardant markets in Japan. Since around 2000, brominated FRs are declining and phosphorus PIN FRs are increasing, but the total national market is stagnating at around 20 million € with a move from commodity FRs to technical engineering solutions. Current FR developments include polymeric, nano- and biobased FRs. A growing PIN FR market is for automobiles, with a push for lightweighting to reduce energy consumption, leading to replacement of metal parts by plastics, and development of demanding fire safety standards for EV batteries. At the same time, recycling is now a priority.
Interview: Japan Society of FR Materials
Masayuki Okoshi. Established in 1996, the Society has some 500 members (individuals), and around 250 company sponsors (of whom one third are OEMs, one third polymer producers and one third flame retardant manufacturers). The Society’s objectives are sharing of information (products, research, regulation, environment), academic research (on FR and fire mechanisms) and communications (symposium, publications …). It is structured as an association, with President and Officers elected by the members. The Society has two committees, on Inorganic and Organic Flame Retardants, made up of volunteer members. The Society publishes a quarterly information newsletter and organises meetings (4 conferences per year, with around 200 participants, open to members and non-members). The annual budget, funding the secretariat is around 130 000 Euros/year. https://sfrm.or.jp/en/
Interview: Pasek Minerales
Jorge Lang-Lenton. Pasek Minerales is developing a process to produce magnesium di-hydroxide (MDH, PIN flame retardant) from Dunite rock mine tailings rich in magnesium silicate. The process separates the mineral components of this secondary material into high added-value and sustainable products, with near zero emissions. Several families of compounds are produced based on silica, magnesium ( magnesium oxide/hydroxide) and different metal hydroxides. The magnesium di-hydroxide obtained is of purity, particle size and geometry to be a quality PIN flame retardant in plastics, in particular for cables. This process has been validated at the laboratory and at the kg pilot scale in in Pasek Minerales’ facilities and scale up to industrial and commercial production is being planned. Pasek Minerales also formulates fire protective mortars made from its mined Dunite. These mortars isolate from fire heat by ceramic heat reflection as well as reducing heat by endothermic reaction (9% weight loss in fire). The mortars also have climate benefits by capturing CO2 (producing magnesium carbonates).
The only presentations concerning halogenated flame retardants were Pieter Hanssen, Lubrizol, on CPVC (PVC with additional chlorine reacted into its molecules) and Daniel De Schryver, Albemarle, presenting brominated flame retardants (for both, see presentations at FriP 2000 in pinfa Newsletter n°109).
Visions from flame retardant applications
Interview: Hutchinson
Raymond Hajj, Materials Development Engineer – Fire-resistant Materials. Hutchinson, established in 1853, has today 40 000 staff worldwide and is a global leader in materials for acoustics & vibration, sealing, fluid and thermal management, sensing & actuation, protection & structure and power transmission. The Group’s vision for the future of mobility emphasizes safety, comfort and sustainability. Hutchinson focuses on developing sustainable materials (revea® range), including materials with emphasis on long-life durability and high performance in extreme temperatures. Hutchinson’s objectives include the development of materials using non-CMR, non-toxic and non-halogenated flame retardants, which can be recyclable and exhibit low smoke and low smoke toxicity in case of fire. Materials must also ensure durability and provide added-value for customers. Current developments include a flame retardant EPDM (ethylene propylene diene monomer rubber) with a UL 94 V-0 rating for e-vehicle battery pack seals and cooling systems, passive fire protection materials for liquified natural gas installations, and aerospace materials for thermal and acoustic insulation. Hutchinson is also looking to develop flame retardant compounds for 3D-printing that achieve good homogeneity, processability and viscosity, while delivering mechanical performance requirements of mobility applications. Some flame-retardant solutions on the market today are inadequate in terms of health and safety, including their impact on processing operators. Hutchinson aims to develop preferable alternatives through its own formulations. The goal is to deliver cost-effective materials that balance performance, processibility and durability, designed to meet the specific needs of customers.
Interview: Metecno Bausysteme GmbH
Meisam Shabanian, Metecno, a manufacturer of polymer foam sandwich panels for building insulation, has switched from PUR (polyurethane) to PIR (polyisocyanurate) foam. PIR offers superior thermal insulation and improved fire resistance at a comparable cost. Currently, the company is focused on advancing fire safety by achieving the BS1-D0 fire classification—a more stringent standard than the current BS2. To achieve this, Metecno is investigating liquid nitrogen-phosphorus (PIN) flame retardant solutions for PIR foams, potentially in combination with mineral compounds to act as smoke suppression catalysts. While traditional flame retardants, such as melamine-phosphorus compounds, expandable graphite, or solid organophosphate FRs, can effectively reduce smoke emissions, they often pose challenges to foam processing. Liquid organophosphate FRs, although available, have not yet demonstrated the ability to meet the BS1-D0 standard. One promising approach involves the chemical modification of polyols using aromatic heterocycles and phosphorus compounds, integrating fire resistance directly into the foam's structure. By adopting cutting-edge chemical modification techniques, it possible to develop PIR foams that meet the highest fire safety regulations while maintaining exceptional thermal performance and processing efficiency.
Interview: SIKA
Sara Fornera, SIKA Thermoplastics division. With 30 000 staff worldwide and 1 000 in R&D, SIKA is a global speciality chemicals company and a leader in development and production of systems and products for bonding, sealing, damping, reinforcing, and protection in construction and industry applications. Sustainability is a core company objective and success factor, leading to focus on flame retardants with minimal environmental concerns and low greenhouse emissions, including in processing. This must be combined with performance, processability, recycling and price. For construction applications durability is essential, and SIKA provides up to 20 years warranties. Recycling is less critical for materials with long durability, but must nonetheless be considered. For roofing membranes (PVC, polyolefins, bitumen), a challenge is to find synergists with low environmental impacts, and there are in particular questions around antimony (ATO) despite its high performance in PVC. The FriP conference shows very active R&D ongoing into flame retardants and SIKA hopes this will deliver continuing improvements in FR sustainability and performance, at prices accessible to customers for volume applications such as construction. construction. See: SIKA in pinfa Newsletters n° 135 and 105.
Interview: Safran Seats
Aditya Ramgobin. Safran Seats is one of the world's leading manufacturers of aircraft seats, for both crew and passengers. 1 million Safran Seats-manufactured aircraft seats are currently in service with air fleets around the world. Requirements are highly demanding, for complexity of seat shell structure (and integrated services such as lights, heating, ventilation, electrical sockets, screens), lightweighting and fire and smoke performance. Heat release is one of the most difficult parameters, as test results can be variable, because they are so demanding. Fire performance of the composites used in seat shells can vary with structural design and cross section, with different additives included in polymers (e.g. colours) and with paints and finishes. This can lead to the need for frequent costly and time-consuming re-testing and re-certification every time specifications are modified or every time a material supplier makes changes. Safran is looking to improve coordination from end-user (airline or aircraft fitting) to materials supplier. Sustainability is a priority for Safran, and moving to environmentally preferable flame retardants poses challenges to find solutions for the necessary materials and fire performance, and can mean re-testing and re-certification
