Production Process Sharing of Flame Retardants: Manufacturing of Anti-Drip Flame Retardant

Production Process Sharing of Flame Retardants: Manufacturing of Anti-Drip Flame Retardant

Process Composition: Substitution, Chlorination, Addition, Washing, Fluorination, Three-Stage Distillation.

I. Substitution
After confirming the production equipment is in normal condition, add a slightly excess amount of PCl₃ into the substitution reactor according to the ratio. Stir the mixture. Recheck that the process gas recovery system is functioning properly, then add pentaerythritol in batches according to the specified ratio. After thorough stirring, initiate heating to start the reaction. Once the pentaerythritol has largely reacted completely, the reaction yields the first intermediate of RX tetrafluoro V100. Subsequently, initiate vacuum to distill and recover the remaining PCl₃ (to be reused in the next batch). After PCl₃ recovery is complete, cool the material inside the substitution reactor.

II. Chlorination
Transfer the substituted material into the chlorination unit for chlorination treatment. The reaction produces the second intermediate of RX tetrafluoro V100. Confirm that the reaction is complete, then transfer the material from the chlorination unit to the addition reactor.

III. Addition
Under vacuum conditions, add the catalyst titanium tetrachloride into the addition reactor. Restore to atmospheric pressure, then slowly add propylene oxide under the liquid surface via dropwise addition. When the addition of propylene oxide is nearly complete, the temperature in the addition reactor begins to decrease slowly. Turn off cooling, continue stirring for several more minutes, then raise the temperature. Recover chloroethane at atmospheric pressure and maintain temperature to ensure nearly complete recovery of chloroethane. The reaction yields industrial-grade RX V100. Transfer the reactor contents to the alkali wash kettle.

IV. Washing
Start stirring in the alkali wash kettle. Add soda ash and water according to the ratio. Slowly raise the temperature to 70°C, then stop stirring and let the mixture settle for 1 hour. Separate the layers and remove the aqueous layer, sending it to the plant's wastewater treatment facility. Transfer the washed, nearly neutral organic layer to the water wash kettle. Start stirring, add water according to the ratio, slowly heat to 70°C, then stop stirring and settle for 1 hour. Separate the layers and remove the aqueous layer, sending it to the plant's wastewater treatment facility.

V. Fluorination
Transfer the organic layer obtained after the second water washing and separation into the fluorination reactor. Under high-speed stirring, slowly add tetrafluoroethylene suspension according to the ratio. After addition is complete, continue stirring for 0.5 to 1 hour to allow full chain combination of the molecular material, forming a uniform and stable industrial-grade RX V100 crude product solution. Then transfer the solution to the three-stage distillation system.

VI. Three-Stage Distillation
Distill off approximately 5% of the lower-boiling point TCPP carried by the industrial-grade RX V100 crude solution from the column top, reducing the TCPP content in the column bottoms product to ≤50 ppm. The three-stage distillation employs a small amount of medium-pressure steam in direct contact with the material for steam stripping, further removing light components and purifying the product (ensuring removal of trace impurities generated during production due to material or operational fluctuations). The final product contains TCPP ≤50 ppm, yielding high-purity RX tetrafluoro V100 anti-drip flame retardant product.

Conclusion
From substitution to three-stage distillation, this seven-step closed-loop process transforms pentaerythritol and tetrafluoroethylene into anti-drip RX tetrafluoro V100 with a purity ≥99.95%. Every drop of propylene oxide and every stream of chlorine gas is precisely utilized under controlled temperature and vacuum gradients, ultimately leaving only a transparent liquid with ultra-low TCPP and high fluorine content. Minimal addition enables molten plastic to form char instantly upon encountering fire and halt dripping within seconds, providing an "invisible fire-resistant armor" for transparent PC, charging station housings, and photovoltaic backsheets.