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Phosphinate flame retardant for polyester injection molding applications

Exolit® OP 1240

Exolit OP 1240 is a flame retardant based on an organic aluminum phosphinate which is a thermally stable white solid without any hazard classification or labeling. It can be easily compounded into polyesters and subsequently processed again to manufacture flame retarded parts used in consumer or industrial products.

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  • Non-hygroscopic, insoluble in water and organic solvents
  • High efficiency due to its high phosphorus content
  • UL 94 V-0 rating down to 0.4 mm thickness
  • Suitable for PET sheet extrusion
  • Suitable for both glass fibre reinforced and unreinforced grades
  • The flame retarded polyester compounds exhibit good physical and excellent electrical properties
  • Good colorability
  • Versatile use with synergists
  • Non-halogenated flame retardant with favorable environmental and health profile
Further safety data and handling information are available from our current Material Safety Data Sheet. For disposal in accordance with the regulations the product should be treated as special waste and taken to a suitable incineration plant.   
Characteristics  Unit Target Value DS¹)  TD²)   Test Method 
Phosphorus  %(w/w) 23.3 - 24.0  

Photometry after oxidizing dissolution; (11/17) or wavelength dispersive X-ray fluorescence spectrometry; (11/23)  
Water / Moisture  %(w/w) max. 0.2  

Thermogravimetry; (11/03)  
Density  g/cm³ 1.35  

at 20° C  
Bulk Density  kg/m³    400 - 600  

Decomposition Temperature  °C  > 300  

(TGA 2% weight loss)  
Average Particle Size (D50)  µm    25 - 50  

¹) Delivery specification: The product is monitored on a regular basis to ensure that it adheres to the specified values. Test methods: Clariant method numbers 11/xx in brackets.
²) Technical data: The technical data are used solely to describe the product and are not subject to regular monitoring.  
Exolit OP 1240 is a flame retardant for thermoplastics and thermosets. Due to its high phosphorus content the product is distinguished by a high efficiency.

Exolit OP 1240 was developed especially for the use in polyesters. It is suitable for both glass fibre reinforced and unreinforced grades. The flame retarded polyester compounds exhibit very good physical and electrical properties.

In PBT, a dosage of 20 % (by wt.) Exolit OP 1240 is usually sufficient to obtain the UL 94 V-0 classification for electrical components (at 1.6 as well as 0.8 mm thicknesses). In PET, less than 15 % are required to pass UL 94 V-0. Synergistic effects are known with other flame retardants like melamine polyphosphate, melamine cyanurate or zinc borates.

Subject to the polymer grade, processing conditions and glass fibre reinforcement the dosage of the flame retardant may vary.
Packaging and Handling
Delivery form
White powder

Exolit OP 1240 is delivered in 20 kg paper bags with PE inliner or 500 kg big bags.

Minimum shelf life is 12 months from the date of shipping when stored according to the said conditions.     
Products that offer outstanding sustainability advantages are awarded Clariant’s EcoTain® label. EcoTain® products significantly exceed sustainability market standards, have best-in-class performance and contribute overall to sustainability efforts of the company and our customers. Find out more about: EcoTain®.
  • Non hazardous, studies on life cycle data available
  • Saves lives and assets as a (halogen free) flame retardant. Supports the attainability of eco-lables for customer products.
  • Phosphorus is on the EU list of critical raw materials but recycling is possible and actively investigated.
  • Very efficient production process with high yield, minimized waste and low water consumption.
  • Extensive work with customers along the value chain, optimizing material performance and evaluating life cycle aspects with stakeholders.




  • Efficient at comparatively low loadings. Synergies with other halogen free flame retardants. High tracking resistance in E&E applications.
Before incorporating Exolit OP 1240, it is important to predry the polyester as usual. If possible, the resulting moisture content should be below 0.05% (by wt.) for PBT and 0.005% for PET. Predrying of Exolit OP 1240 is not necessary. However, predrying (e. g. 4h at 120 °C) is recommended, if even very low moisture contents must be avoided.

Wear and corrosion protected screw elements are recommended when using Exolit OP 1240 in reinforced polyesters.

The mixing and processing methods customary in powder processing of polymers can be used with Exolit OP 1240. The VDI Guideline 2263 “Prevention of dust fires and dust explosions” or the relevant national regulations must be observed. The optimum conditions for incorporating should be determined in each individual case. Care must be taken to ensure homogeneous dispersion of all components. The temperature of the polymer melt should not exceed 320 °C.

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Exolit® OP 1240

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