Halogen-free PP flame retardants are mainly composed of phosphorus and nitrogen-based flame retardants. They are characterized by being halogen-free, environmentally friendly, having good temperature resistance, and available in various models. They are widely used in electronics, automobiles, new energy, construction, and rail transportation, and are suitable for polyolefin materials such as PP, glass fiber reinforced PP, PE, TPE, TPU, and EVA. They meet UL 94 V-0 (0.75mm), 1581 VW-1, GWIT 750℃, GWFI 960℃ glow wire, 70℃×168-hour immersion test (UL746C), RoHS, and REACH requirements. The characteristics and processing precautions of halogen-free PP flame retardants are as follows.

I. Characteristics

1. Flame-retardant products feature smooth surfaces, strong resistance to exudation, excellent water resistance, superior migration resistance, excellent electrical properties, and low smoke and toxicity. There is no hydroplaning during extrusion.

2. Good UV stability, high thermal stability, good dispersibility, fine particle size, resulting in smooth surfaces, low density, low smoke emission, and strong charring ability in flame-retardant products.

3. Halogen-free PP flame retardants can retard glass fiber reinforced PP, exhibiting excellent machinability, low overall cost, and high cost-effectiveness.

4. Flame-retardant products exhibit low mold corrosion, low density, and low smoke emission. When applied to polyolefins, toughening systems such as POE can be used without affecting flame retardancy.

II. Processing Precautions

1. Fillers or colorants such as talc, barium sulfate, and wollastonite may adversely affect halogen-free PP flame retardants; the addition amount needs to be adjusted according to experiments. Calcium carbonate, talc, and phthalocyanine green can lead to a decrease in flame retardant efficiency or even inactivation.

2. Do not add screens during extrusion processing, as this can easily lead to foaming. A certain degree of vacuum must be maintained during twin-screw extrusion.

3. The addition of low-quality carbon black, fillers, and certain organic pigments can affect the flame retardant properties of the product. It is recommended to use ink black to prepare black products.

4. Only coupling agent needs to be added during use. If customers need to add other additives, a small-scale test should be conducted beforehand.

5. The processing temperature of the twin-screw extruder can be adjusted according to the specific model and decomposition temperature of the halogen-free PP flame retardant. The initial temperature should be kept as low as possible during extrusion processing, and the maximum processing temperature should not exceed the decomposition temperature of the flame retardant.

6. Keep the product dry during processing. If it accidentally gets damp, it can still be used after drying until the moisture content is below 0.25%.

There are many formulations of halogen-free PP flame retardants. Each formulation has different decomposition temperatures, particle sizes, prices, phosphorus and nitrogen content, fillers, flame retardant mechanisms, advantages and disadvantages, and dosage requirements. Different flame retardant specifications are required to achieve the ideal flame retardant effect, depending on the flame retardant rating, polymer material, and the physical and chemical properties of the product. For detailed technical specifications and usage questions, please contact our technical department.