Conductive plastic is a functional polymer material that mixes resin and conductive materials and is processed by plastic processing. It is mainly used in electronics, integrated circuit packaging, electromagnetic wave shielding and other fields.
Conductive plastics not only have a rapid development in the application of antistatic additives, computer anti electromagnetic screens and smart windows, but also have a wide application prospect in the fields of light-emitting diodes, solar cells, mobile phones, micro TV screens and even life science research. In addition, the combination of conductive plastics and nanotechnology will also promote the rapid development of molecular electronics.
1、 Main uses and types of conductive plastics
(1) In the field of electronics and electrical appliances, it is used as anti-static turnover box, IC and LCD tray, IC package, chip carrier, film bag, etc. used in the production of precision electronic components such as integrated circuit, chip and sensor sheath.
(2) The shell and structural parts of explosion-proof products, such as the shell and structural parts of electrical products used in coal mines, oil tankers, oil fields, dust and combustible gases.
(3) Semi conductive shielding material used in medium and high voltage cables. (4) EMI shielding shell of electrical products in the fields of telecommunications, computers, automation systems, industrial electronic products, consumer electronic products, automotive electronic products and so on.
(5) Conductive plastics usually include conductive PP, conductive PE, conductive ABS, conductive PS, conductive MPPO, conductive PPO, conductive PPE, conductive nylon PA, conductive PBT, conductive PC, conductive PPS, conductive Pei, conductive Pu, conductive TPR, conductive TPV, conductive TPE, conductive ABS, conductive EVA, conductive K glue, conductive PC / ABS, conductive PC / PBT, conductive PVC / ABS, conductive EPDM, conductive sis, conductive SBS, conductive PMMA, conductive POM, conductive PPR, conductive PPA Conductive rubber, etc.
2、 Development of conductive plastics at home and abroad
Anti static filling type
The advantage of antistatic agent filled products is that the coloring of products is not limited. Among them, low molecular antistatic agent has little effect on the performance of products, and its surface resistivity is 1010-1013 Ω. However, the electrical properties of low molecular antistatic agent filled products will gradually lose with the passage of time. At present, the main development trend abroad is to develop and produce polymer antistatic agent. Polymer antistatic agent can also be called permanent antistatic agent. It will not lose its conductivity after washing or long-term use like low molecular antistatic agent. The main varieties of polymer antistatic agents are polyether type, quaternary ammonium salt type, sulfonic acid type, acid graft copolymer and ionic type. The main manufacturers include Sanyo Huacheng, Sumitomo Jinghua, Sumitomo science industry and first industrial pharmaceutical in Japan, Ciba Jinghua and Clariant in Switzerland, Waco and Great Lakes in the United States, etc. The addition amount of high molecular antistatic agent is 5-15 times that of low molecular antistatic agent. At the same time, we should also consider its compatibility with resin, so as to select the appropriate compatibilizer. Due to the restriction of cost, its application is limited to a certain extent. At present, low molecular antistatic agents, especially ionic antistatic agents, are mainly used in China, which are easy to crack and are greatly affected by environmental humidity.
Carbon filled
This series of fillers are mainly conductive carbon black, graphite and carbon fiber, and the volume resistivity of the finished product is 102-109 Ω· cm. Among them, carbon black filling is the mainstream. The reason why carbon black filled conductive polymers are widely used is that the price of conductive carbon black is relatively low; Second, because carbon black can have a large choice according to different conductivity requirements, the resistance value of its finished products can vary in a wide range between 102-109 Ω; Third, the conductivity is long-lasting and stable; Therefore, it is an ideal antistatic material.
However, its finished products are limited to black and have a great impact on the material properties, so it needs supporting modification technology. In order to improve and improve the toughness of conductive plastics and maintain better physical properties and excellent and stable conductive properties.
Metal filled
This kind of conductive plastic is mainly used for electromagnetic wave shielding. In recent years, due to the development of integrated circuit and large-scale integrated circuit technology, digital electronic machines have developed from industrial use to civilian goods. In order to improve the processing capacity, the electronic circuits and components used are more and more integrated, miniaturized and high-speed, and the signal level is reduced, which makes the electromagnetic wave invaded from the outside close to the control signal. In addition, electronic equipment also radiates electromagnetic waves, so it is easy to cause misoperation, image and sound interference of electronic machines. In the 1980s, most of the shells of electronic machines used plastic materials instead of metal. This is because the plastic shell has the advantages of light weight, high strength, corrosion resistance, easy processing, high production efficiency and low total cost. However, plastic is an insulator, which can completely transmit electromagnetic waves. Therefore, endowing plastic shell with electromagnetic wave shielding ability has become a very urgent topic to be studied.

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