Method and system for drying wet polytetrafluoroethylene dispersion resin particles

Abstract

The invention belongs to the technical field of organic chemical drying and discloses a method and a system for drying wet polytetrafluoroethylene dispersion resin particles. A drying device, a decontaminating device, a low-temperature air cooling device and hermetical packaging device are connected through a mesh belt conveying device to form a tunnel type continuous processing cyclic conveying loop to orderly and effectively complete procedures of wet feeding, microwave drying, microwave superheat steam drying and decontaminating, cooling and hermetical packaging of polytetrafluoroethylene dispersion resin particles, and consequently high-quality polytetrafluoroethylene dispersion resin particles low in moisture content and impurity residue and free of caking and fiberizing are produced while environmental influences are effectively avoided. In addition, the method and the system are short in material drying period, high in drying system efficiency, easy in automatic feedback control and suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a wet material drying system and method, in particular to a polytetrafluoroethylene dispersed resin particle wet material rapid and continuous drying system and method, belonging to the technical field of organic chemical drying. Background technique [0002] Polytetrafluoroethylene (PTFE) is a polymer compound with excellent high and low temperature resistance and chemical stability, as well as corrosion resistance, high electrical insulation, high flame retardancy and low thermal conductivity. The usual polytetrafluoroethylene products are made of polytetrafluoroethylene suspension resin powder or dispersed resin particles; among them, polytetrafluoroethylene dispersed resin particles are made of monomer tetrafluoroethylene (TFE) with dispersant, The emulsifier and initiator are polymerized in water, the polymerization temperature is 40-80°C, and the pressure is 0.3-2.6MPa. The polytetrafluoroethylene dispersed resin particle...

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Problems solved by technology

[0007] First, in the first drying process, a metal bottom tray is used to load the material. Although according to its patent description, a certain height is maintained between the upper and lower trays so that the microwave can heat the material, but according to the microwave heating theory, the metal bottom plate will reflect and interfere with microwave coupling. It will reduce the microwave heating efficiency, resulting in a longer microwave drying time in this process, and the moisture after drying is still as high as 20%;

[0008] Second, the total drying cycle is still long, and the first and second drying processes, which account for most of the drying cycle, are continuously feeding and discharging air, so air dust pollution is unavoidable for PTFE dispersion resins. Effects on particle quality and stability;

[0009] Third, the temperature maintained in the third process, even the temperature in the whole drying process, does not exceed 155-160°C, which is lower than the boiling point of the main impurities in the material (for example, the boiling point of PFOA with the highest residual ratio is 189-191°C) , it is difficult to achieve the purpose of removing impurities, and ultimately affect the quality indicators such as product color and smoothness;

[0010] On the whole, the existing PTFE dispersed resin particle drying technology or device has problems such as slow drying speed, long drying cycle and high energy consumption, as well as product pollution due to the use of external air, and even agglomeration and fibrosis And affect the quality of finished products and other issues

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