Polytetrafluoroethylene (PTFE) has always enjoyed the reputation of "King of Plastics". It has excellent chemical resistance, thermal stability, dielectric properties, non-stick and self-lubricating properties, and has a unique position in plastic materials. According to ACMI statistics, the current global PTFE production capacity is about 320,000 tons/year, of which China accounts for 65.84%, and the production capacity growth is stable. So, so much PTFE is produced every year, how to recycle the waste PTFE?
Due to the stable nature of PTFE, if it is buried deep underground, it may not necessarily be degraded even after 1000 years. The method of incineration will produce toxic gases and pollute the environment. The editor sorted out the current mainstream recycling methods of PTFE, including: mechanical crushing method, radiation cracking method and thermal decomposition method, let's find out together!
Mechanical Pulverization
The mechanical pulverization method refers to cleaning the PTFE waste and pulverizing it with a cutter, ball mill, or airflow pulverizer. The mechanical pulverization method has the characteristics of high efficiency, energy saving, and high return rate, and it is also the easiest way to realize industrial production. The PTFE waste is crushed by mechanical force, and PTFE fine powder with different fineness can be obtained according to different process settings. Because the mechanical pulverization method has high requirements on purity, at present, this method is mainly aimed at defective products, mechanical grinding waste and residual materials in the production process.
Radiolysis
The radiation cracking recovery method is suitable for pure PTFE products, because the additives in PTFE are generally glass fiber, molybdenum disulfide, copper powder, etc. Glass fiber will change color when exposed to high-energy rays. The particle size of the added copper powder is generally about 40 μm, and the high-energy rays cannot further refine the particles to 10-20 μm. Therefore, the radiation cracking method is suitable for defective products, residual materials and scraps during the processing of pure PTFE.
Pyrolysis
Pyrolysis is to use higher temperature to decompose PTFE. This method is difficult to control the types of decomposition products, and also produces many toxic by-products. In the process of recovering useful decomposition products, the requirements for process equipment and parameter settings are relatively high, and the application of this method is generally not encouraged.
