Polyetheretherketone (PEEK) is a special engineering plastic with high heat resistance, which has high heat resistance among thermoplastics, and has excellent mechanical strength, electrical properties and radiation resistance. It can be extruded, Processing methods such as injection and pressing are processed into shapes, and profiles can also be processed by mechanical processing methods. PEEK has been widely used in special industries, such as aerospace parts, special mechanical parts, military structural parts, military electronic parts, nuclear power and other high-tech fields
Since the directly produced polyetheretherketone contains a large amount of inorganic ions, when used in electronic and electrical applications, the presence of inorganic ions will reduce the insulation performance of polyether ether ketone, and the purpose will be harmful to semiconductors and conductor materials during use. Corrosion is caused, and then leakage occurs or the performance of the device deteriorates, resulting in a decrease in stability or failure of the device. Therefore, it is necessary to reduce the inorganic ion content in polyetheretherketone when it is used in electronic and electrical applications.
Polyether ether ketone PEEK refining process Existing process analysis
(1) Acetone refining process
Transfer the crude PEEK resin in the silo to the acetone refining kettle through the pneumatic conveying system, add a certain amount of 95% acetone, use steam to indirectly heat the refining kettle to 56 ° C, and carry out constant temperature stirring. Acetone is used as the extraction agent to extract the crude product Diphenyl sulfone, after stirring for a period of time, the material is automatically layered, the upper layer is diphenyl sulfone acetone solution, the lower layer is PEEK resin, sodium fluoride and a small amount of undissolved diphenyl sulfone, and the upper layer solution (containing diphenyl sulfone Phenylsulfone, acetone) are pressed into the acetone distillation kettle (atmospheric pressure, temperature 56°C) through a filter screen, and acetone is added to the acetone refining kettle for extraction (used to dissolve undissolved diphenylsulfone). This process is repeated about 8 times , to obtain qualified salt-containing PEEK resin. The steam from the acetone distillation tank is condensed by the primary and secondary condensers (the freezing water deep condensation efficiency is 90%), and then the liquid acetone is refluxed to the acetone intermediate tank and reused in the refining tank. Recycled acetone was used for the first 7 times of acetone refining process, and fresh acetone was used for the last time.
(2) Water purification process
Transfer the salt-containing PEEK resin into the water refining kettle, add a certain amount of deionized water to the water refining kettle, heat to 90°C, stir at constant temperature for 1 hour to dissolve the sodium fluoride, and let it stand for a while. Then open the valve of the high brine storage tank, feed nitrogen to filter the sodium fluoride in the water refining kettle to the high brine storage tank, repeat this process 2 times, most of the sodium salts are removed, then close the high brine storage tank valve, The high-salt wastewater in the tank is pumped into the three-effect evaporator for atmospheric pressure evaporation and desalination. The three-effect evaporator uses steam as the heat source.
Add a small amount of phosphoric acid solution into the water refining tank to rinse (phosphoric acid is mainly to adjust pH), after stirring and rinsing, open the valve of the phosphoric acid intermediate tank, and use nitrogen to filter the dilute phosphoric acid solution in the water refining tank into the phosphoric acid intermediate tank for recycling.
Then add deionized water again in the water washing kettle to continue refining (a small amount of sodium fluoride), this process repeats about 6 times, until the conductivity of the aqueous solution is 10us/cm, the filtrate after this part of washing is discharged into the refined water reuse storage tank . The deionized water in the reuse water storage tank can be reused as the purified water in the next batch of pre-process. Remove the wet product PEEK resin of sodium fluoride into the next step.
(3) Centrifugation process
The wet PEEK resin after water purification is transferred to a centrifuge for airtight centrifugation to obtain PEEK resin, which is to be dried.
(4) Drying process
The centrifuged wet PEEK resin is transferred into a double-cone rotary vacuum dryer by vacuum suction for vacuum drying (about 140°C).
In the existing polyetheretherketone PEEK refining process, there are often unit operations such as multiple solvent washings, multiple filtrations, multiple heating and water washing, and drying. These unit operations are usually performed by refining kettles, water washing kettles, filter presses or Unit equipment such as centrifugal filter, washing tank and dryer operate independently, and various unit equipment are connected into a large device with a long process, and materials are transported between equipment through pipelines or other methods. Each unit operation corresponds to the corresponding unit equipment, and the equipment is dispersed. Large, the leakage of the equipment connection will cause material and environmental pollution.
In order to overcome the defects in the existing purification technology of polyetheretherketone (PEEK), a new conical filter, washing and drying three-in-one multifunctional equipment (patent number: ZL202022908020.2) developed by Wuxi ZhangHua can meet the requirements of fully automatic polyetheretherketone (PEEK) ) purification process requirements, this method can not only obtain polyether ether ketone with low inorganic ion content, but also can effectively recycle and reuse the purification treatment agent. Compared with the current method, it has time-saving, energy-saving and purified polyether The ether ketone resin has the characteristics of high quality, and has the advantages of simple process and easy operation.
Conical filter, washing and drying three-in-one technical features
(1) The production system process is fully enclosed
Due to the innovative application of the fully enclosed material conveying system, the fully enclosed production process from the beginning of crystallization to the end of subpackaging can be fully realized. The three-in-one conical filter, washing and drying system is a fully enclosed system, and the production process is more in line with GMP requirements.
(2) Safety and environmental protection
Due to the conical three-in-one fully enclosed operation, it can completely avoid the pollution of the operating environment air by solvents during the production process, and at the same time reduce the occurrence of operator poisoning accidents caused by contact with toxic substances. This advantage is even more important today when the calls for environmental protection and labor protection are rising day by day.
(3) High-speed washing, because this equipment can re-stir and suspend the filter cake during the washing operation, so that the filter cake can be washed very thoroughly.
(4) Operate under pressure or vacuum to realize solid-liquid separation. When filtering, the filter cake is evenly distributed, and the solid-liquid separation effect is good.
(5) When the material is heated in the container, it clings to the inner wall of the container and rotates from bottom to top with the inner heating ribbon to the upper part of the container, and then vortexes downward along the main axis.
The material is always dispersed and moved throughout the drying process, ensuring balanced heating.
(6) Clean production. The conical filter, washing and drying three-in-one can operate in a closed manner, and is equipped with a dust collector to completely collect the dust generated after drying, which can meet the production and operation requirements of high cleanliness.
(7) The product yield is high, and the solvent recovery is complete. Because the entire production system is a fully closed system operation, materials and solvents can be completely recovered 100%, avoiding waste caused by material omission, legacy and solvent volatilization, which has great economic benefits, especially in the treatment of materials and the use of solvents Even more so at higher values.
(8) High degree of automation and easy to master.
Each process is carried out in stages, and the safety measures are complete. The operators can complete the operation after simple training, and the work intensity is greatly reduced.
(9) For highly corrosive materials, the interior of the equipment can be lined with corrosion-resistant materials. The stirring shaft, mechanical seal and discharge ball valve components are made of special alloys with excellent corrosion resistance.
(10) Stirring, mixing, and beating can be carried out in the body before filtration, and various technological operations such as cleaning, regeneration, and drying can be carried out in the body after filtration.
It has the characteristics of simplifying the process flow, improving production efficiency, preventing material pollution, convenient material replacement, and mechanical and electrical integration. At the same time, the plant area of the whole production process is greatly reduced, and the basic investment cost of customers is reduced.