ADDITIVES | POLYAMIDES
Right: Clariant has developed melamine-free Exolit AP 422 A flame retardant in anticipation of the current and future regulatory challenges around melamine
dispersion and stability, smoke suppression, and anti-dripping properties, along with better flow and processability which improves processing efficien- cy in injection moulded and extruded parts. Chinese FR manufacturer Zhejiang Wansheng,
which recently opened a new 400,000 m² factory in Shandong province, has launched WSFR3104, its first solid halogen-free FR for use in PA. The company says in 30% glass fibre-filled PA 66, the new additive shows improved flame retardant efficiency and better mechanical properties compared to competitive products. In tests, compounds with WSFR3104 were capable of reaching GWIT 775° C in combination with UL94- V0 at 0.8 mm thickness at addition levels consider- ably lower than combinations of ADP, melamine polyphosphate, and zinc borate. After recycling 100% of the compound three times in a twin-screw extruder, all properties remained intact. Full-scale production is expected to begin in 2026. Due to growing concerns regarding the safety of triphenyl phosphate (TPP), a by-product of the production process, the company has also signifi- cantly reduced its use in its existing FR additives WSFR-BDP and WSFR-RDP, and invested in further purification steps in the production of these additives. The improved WSFR-RDP-L was recently launched with a TPP content well below the 0.1% threshold. Fraunhofer LBF said it is looking for partners in Germany for the HFFR-Up2Cycle project which is aiming to upgrade PCR materials, including recycled PA, with halogen-free flame retardants to improve their flame retardancy and enhance their long-term mechanical and thermal properties. For more than two decades, Exolit OP flame
retardants from Clariant have combined robust FR performance with excellent material properties and best-in-class sustainability. This is one area in which
54 COMPOUNDING WORLD | April 2025
the company is always looking to improve and is constantly evolving its portfolio to meet the challenges of its customer base. “Take electrical cars as an example, as they bring completely new challenges to compounds,” said Sebastian Hoerold, Head of Application Develop- ment for Additives Polymer Solutions at Clariant. “These include the need for a Comparative Tracking Index (CTI) of 600 V and above, sufficient resistivity against water and other fluids, as well as keeping flame retardancy and electrical properties after heat aging to name a few. Polyamide com- pounds that contain Exolit OP can meet all these technical challenges and in addition, help custom- ers to achieve certain sustainability targets. A study from Fraunhofer LBF has shown that PA GF com- pounds containing Exolit OP 1400 maintain their UL 94 V-0 rating when recycled back into produc- tion streams multiple times. It is maintained as well throughout an aging time of 1,000 hours at 120° C simulating for post-consumer recycling.”
Melamine alternative The most recent addition to the range is the melamine-free Exolit AP 422 A, billed as a “safer and forward-thinking solution” that provides superior fire resistance and meets the stringent demands of modern industries. In anticipation of the current and future regulatory challenges around melamine, which was classified as a Substance of Very High Concern (SVHC) in 2023, Clariant has been proactively working on this innovative solution for several years, developing an SVHC-free alternative to the existing melamine- containing Exolit AP 422 flame retardant. “Exolit AP 422 A responds to key market trends
around tightening fire safety standards, environ- mental and health concerns, regulatory compliance needs, operational efficiency demands, and the
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IMAGE: CLARIANT
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