Development status and application prospect of the

The development status and application prospects of conductive plastics

conductive plastics are functional polymer materials that mix resins and conductive substances and process them in the way of plastics. It is mainly used in electronics, integrated circuit packaging, electromagnetic wave shielding and other fields

conductive plastics not only have rapid development in the application of antistatic additives, computer anti electromagnetic screens and smart windows, but also have broad application prospects in the fields of light-emitting diodes, solar cells, mobile, 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. In the future, human beings can not only greatly improve the computing speed of computers, but also reduce the size of computers. Therefore, some people predict that notebook computers in the future can be installed in watches

I. main uses of conductive plastics

(1) anti static turnover boxes, IC and LCD trays, IC packages, chip carriers, film bags, etc. used in the production of precision electronic components such as integrated circuits, wafers, sensor jackets, etc. in the electronic and electrical fields

(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 materials 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, etc

II. Development status of conductive plastics at home and abroad

1. The advantage of antistatic agent filled products is that the coloring of products is not limited. Among them, low molecular antistatic agents have little effect on product performance, and its surface resistivity is Ω. However, the electrical properties of low molecular antistatic agent filled products will gradually lose over time

at present, the main development trend abroad is to develop and produce polymer antistatic agents, which can also be called permanent antistatic agents. It will not lose its conductivity after washing or long-term use like low molecular antistatic agents. The main varieties of polymer antistatic agents are: polyether type, quaternary ammonium salt type, sulfonic acid type, acid graft copolymer, ionic type. The main manufacturers include Sanyo Chemical, Sumitomo specialty chemicals, Sumitomo science and industry, first industrial pharmaceutical in Japan, Ciba Specialty Chemicals and Clariant in Switzerland, and Waco and Dahu in the United States. The addition amount of high molecular antistatic agent is times that of low molecular antistatic agent. At the same time, the compatibility with resin should be considered to select the appropriate compatibilizer. Due to the cost constraints, its application is limited. At present, low molecular antistatic agents are mainly used in China, and representative manufacturers include Hangzhou Plastic Research Institute, Beijing Chemical Industry Research Institute, etc

2. Carbon filled type

this series of fillers are mainly conductive carbon black, graphite and carbon fiber, and the volume resistivity of the finished product is 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 has a large choice according to different conductivity requirements, the resistance value of its finished products can vary in a wide range between Ω; Third, the conductivity is durable and stable; Therefore, it is an ideal antistatic material. However, its finished products are only limited to black, and have a great impact on the material properties, which requires supporting modification technology

in foreign countries, carbon filled conductive plastics have become a very mature market. The larger manufacturers include Cabot company, Yuanlian carbon company, GE company, 3M company in the United States, Toshiba chemical and Sumitomo phenolic plastics in Japan are the main manufacturers, as well as Toray, Toyo ink manufacturing, Tokyo ink, Japan Synthetic rubber, Kobe Steel Institute, etc., premix in Finland, LG company in South Korea

3. Metal filled conductive plastics such as

are 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 outward, so it is easy to cause malfunction, image and sound interference of electronic machines. In the 1980s, the shells of electronic machines were mostly made of plastic 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 is completely permeable to electromagnetic waves. Therefore, endowing plastic shell with electromagnetic wave shielding ability has become a very urgent topic to be studied

in recent years, the conductive plastic method has attracted people's interest. At present, the inspection plans known in Europe and the United States are mostly concentrated in the third quarter, and there are many research reports. This is because the conductive plastic method has three significant advantages: ① no secondary processing; ② Shielding and molding products are completed at one time (labor-saving and economic); ③ It is safe and reliable in the long-term use process (such as vibration, damp and hot environmental factors), and will not peel and fall off like the surface method

III. Development Prospects

the substitution of polymer materials for metal materials is the development trend in the field of Materials Science in the future. As a result, the market demand for conductive polymers is increasing, and their application fields are gradually expanding, which inevitably puts forward higher requirements for conductive polymers. For structural conductive polymers, in order to be further applied, the following main problems must be solved:

(1) less stability 7 Nondestructive testing instruments (magnetic particle flaw detector, X-ray flaw detector γ Radiographic flaw detector, ultrasonic flaw detector, eddy current flaw detector, acoustic emission detector, etc.); The oxygen atom in the lack of conductivity polymer has overcurrent, overvoltage, overspeed, overload and other protective devices, which is extremely unstable to water, which is the biggest problem hindering its application

(2) most dopants are toxic, such as asf5, I2, B full load is only 5nr2, etc

(3) forming difficulty the conjugated structure in the main chain of conductive polymer makes the molecular chain rigid and insoluble, which makes it difficult to form freely

(4) poor economy, its price is higher than that of metal and ordinary plastics, and it is difficult to be applied. (end)