Plastic antistatic agentOverview

Plastics have excellent electrical insulation properties. This is because most of their molecular chains are composed of covalent bonds, which can neither ionize nor transfer free electrons. Therefore, once they are charged due to the gain and loss of electrons during friction, it is difficult to disappear through conduction. This is why plastics are easily electrostatically charged.

When the surface resistance of an object is greater than 10 13 ohms, it has no antistatic ability (most plastic products are above 10 15 ohms), but when it is less than 10 10 ohms, it has good antistatic properties. Therefore, in order to reduce the resistance value on the surface of plastic products, some kind of additive must be added. This is the function of antistatic agent.
Because plastic products contain static electricity, they have certain hazards in industrial production, which are manifested in the following aspects:
1. Adsorption of plastic products is serious due to electrostatic dust collection, which not only affects the appearance but also reduces product quality. For example, plastic film packaging is often affected by static interference and is difficult to separate into seals. Film and records are directly affected by dust absorption, which directly affects the clarity and sound quality.
2. Electric shock It is generally believed that when the static voltage is as high as 7,000 volts, people cannot touch it. However, the static voltage generated during the production of film films is often as high as several thousand volts. Another example is that when people are in places where a large number of plastic products are used, they often feel an electric shock.
3. Discharge and combustion Static electricity can cause discharge and combustion. It can be divided into spark discharge and corona discharge. When the gas between the electrodes is completely ionized, spark discharge occurs when a strong current passes between the two electrodes; and when only part of the insulation between the electrodes is destroyed, corona discharge occurs. Corona discharge is mostly continuous and makes a hissing sound, and sometimes it develops into spark discharge.

Although the energy of electrostatic discharge itself is not large, the harm is not small. During the film production process, when the static voltage generated is greater than 4,000 volts, sparks will be released, causing exposure. It is even more dangerous especially in the presence of flammable and explosive materials. There have been records abroad of fires and explosions caused by the use of plastic conveyor belts to transport coal, and there are also reports of oil tankers burning due to electrification of foam plastics. The danger is greater when plastic pipes are used to transport petroleum, organic solvents and other flammable liquids with low conductivity. Because static electricity has so many hazards, antistatic agents have become an additive that cannot be ignored in the plastics industry.

With the development of the plastics industry, antistatic agents have also developed rapidly. There are many ways to classify antistatic agents, usually based on their chemical structure and usage methods. According to the chemical structure, it can be divided into cationic, anionic, non-ionic, zwitterionic, polymeric and semiconductor types; according to the use method, it can be divided into external coating and internal addition; according to performance, it can be divided into temporary and permanent.