Polycarbonate is a polymer having organic functional groups linked together by carbonate groups. The most commonly used are thermoplastics with long molecular chains. The properties of many polycarbonates depend on their molecular mass and structure. As the molecular weight increases, the polymer becomes more rigid. In addition, by mixing it with other polymers (such as ABS and polyester), properties can be changed. Due to its excellent properties, such as transparency, impact resistance, and heat resistance.
The most common manufacturing process is based on the reaction of bisphenol A (BPA or Bis-A) and phosgene in the interfacial polymerization process. However, the phosgene process has many disadvantages, including the toxicity of phosgene, low boiling point solvents, and a large amount of wastewater. Many companies have independently developed and are using non-phosgene processes. They all use the same overall method, where the polymerization relies on the transesterification of diphenyl carbonate (DPC) and bisphenol-A. This is commonly referred to as the melting process.
Alfa Chemistry provides customers with a balanced filtration method for the polycarbonate production process, using advanced proprietary technology to enhance filtration performance and promote the continuous operation of the truly optimized process. Regardless of the process route used-phosgene, non-phosgene or biological, we offer a variety of solutions to suit every step of your production process.
Raw Material Filtration
Alfa Chemistry's balanced filtration method starts with the filtration of raw materials and polycarbonate solutions. Our polymer-based disposable filter product portfolio provides many solutions for the effective filtration of phosgene gas and bisphenol A (BPA, phenol, caustic, additives, solvents, and catalysts). The pleated sintered metal mesh filter is an excellent solution with absolute rated media and high surface area filtration. Advanced sintering design can achieve higher dirt holding capacity, thereby extending the operating life and reducing maintenance frequency. The filter solution is easy to clean and has a strong structure that can be used for a long time.
The prepolymer filter is located downstream of the reactor and can be customized as a 2.5-10 micron PMF folded metal fiber filter or a 0.2 micron folded PTFE filter, depending on the end-use of the polymer. Our prepolymer filter uses hard sintered true random fiber media, tapered hole geometry, and high porosity, which has a high dirt holding capacity and can efficiently remove large agglomerates and hard contaminants.
Polymer Melt Filtration
Melt filtration is the final polymer filtration step of the polycarbonate process and is essential to ensure the highest quality of the final product. The melt filtration system solution adopts CPF technology and a diverter valve, which can realize continuous operation.
In addition, the segmented filter element design uses a unique composite metal medium (PMF) to sinter random fibers, metal powder, and metal mesh together to provide the most effective and consistent filtration. This advanced filtration system provides flexibility because it can also be used for optical or general-purpose polymer production.
As a global leader in high-tech polymer filtration solutions, our filtration solutions have been widely used by most major industry players to produce various polycarbonate grades. Please contact our team of filtration experts to learn more about how industry-leading filtration technology can improve your polymer production process.