Static electricity of plastics and its prevention
What is static electricity? It refers to a relatively static charge, usually refers to the positive and negative charges on the surface of an object caused by the friction between different objects.
2. Electrostatic discharge: refers to the transfer of electrostatic charges between objects with different electrostatic potentials caused by direct contact or electrostatic induction. Generally, it refers to the phenomenon of discharging through the medium after the energy of the electrostatic field reaches a certain level.
Three causes of static electricity: 1 Microscopic reasons According to the theory of atomic physics, matter is in an electrical equilibrium state when it is electrically neutral. Due to the contact of different material atoms, the gain and loss of electrons cause the material to lose its electrical balance and generate static electricity.
2 Macro reasons: Friction between objects generates heat and excites electron transfer;
Electron transfer due to contact and separation between objects;
Unbalanced distribution of surface charge on objects caused by electromagnetic induction;
The combined effects of friction and electromagnetic induction;
Four plastics are polymer materials, and the surface resistance and volume resistance are all more than 10 to the power of 12. Therefore, good insulation properties are imparted to the plastic material. Because of this reason, he is prone to generate static electricity, because plastic and its products are in production, handling, contact, separation, friction, and collision. It is very possible to involve electromagnetic induction, and it is even impossible to avoid them. That brings about the cause of static electricity. How to prevent effectively is a topic that people have paid attention to and expected for many years.
Five plastic anti-static concept: when the surface resistance of plastics and products: more than 10th power is easy to generate static electricity; between 8-10th power has a certain antistatic performance; between 6-8th power is very good It has the best antistatic performance between 4th to 6th power; when it reaches 4th power or less, it has considerable conductivity and belongs to conductive semiconductor materials. 6. Prevention and control of plastic static electricity: 1 Add some materials that have hygroscopic effect and are harmless to plastics (auxiliaries) to reduce its surface resistance. This is the antistatic agent for plastics. Use the type of antistatic agent selected according to the type of plastic. ; Both ionic and non-ionic are hygroscopic antistatic agents. After adding these additives, rely on such materials to absorb moisture in the air and reduce surface resistance to achieve antistatic performance.
2 Directly using plastic with conductive properties to process its products, this is the origin of conductive plastic (resin). Judging from the current domestic market, most conductive plastics are still in black-colored additive-type conductive plastics; light-colored conductive plastics are still under development.
Seven antistatic agents. Selection of conductive plastics: 1 Antistatic agents are mainly produced in Zhejiang, Shanghai, Beijing and other places. According to the type of plastic, they are divided into PVC PP.PE ABS.HIPS and other types. The prices are tens of yuan / kg. －3%, the general surface resistance value after adding: 10 to the power of 8-10, especially in areas with high humidity, the value is significantly smaller. The effect of foreign imports is better than that of domestic ones, and it can reach 8th power even in relatively dry areas. Due to the action mechanism of this type of antistatic agent, the antistatic performance cannot be improved. The antistatic masterbatch is suitable for most plastic raw materials that are granular and easy to add. Its main ingredients are: carrier + antistatic agent + other additives. . 2 Conductive plastics At present, the common ones in China are made of nano-scale conductive carbon black added with resin. Its varieties include PC PET PP PE ABS HIPS PVC and various plastic alloys, but most of them are black. Rarely seen in light colors. The prices are 16-30 yuan / kg. The main place of origin is Guangdong, Zhejiang, Shandong, Beijing and other places.
3 Light-colored antistatic plastics. Adding nano zinc oxide whiskers in plastics can reduce the surface resistance of plastics, which is currently expensive. It is used less and is being promoted during the trial.
The emergence of antistatic plastics has played a very important role in promoting and developing plastic products, and has also ensured the demand for antistatic products. Especially the packaging of electronic products and plastic products for anti-static occasions. Analysis of the increase in demand from the current situation has a good development momentum!