Antistatic agent mechanism of material, have been born in charge in the process of friction and leakage, and constantly.
Charge leakage mainly through the friction material volume conduction, surface conduction and radiation into the air three ways.
Generally solid volume resistance of the surface resistance is 2 - higher
3 orders of magnitude,
High 100 -
, charged to prevent role mainly controlled by the surface resistivity of polymer material, namely surface conduction in charge leakage is the main, so people usually by means of reducing the surface resistance and improve the surface electric conduction method achieves the goal of preventing static electricity.
The external mechanism of the external antistatic agent of antistatic agent on water, alcohol, or other organic solvent as solvent (
Or dispersing agent)
, with the concentration of 0.
0% of the solution, then antistatic coating on the surface of the plastic, antistatic agent molecular lipophilic group will be adsorbed on the surface of the plastic, the plastic surface with antistatic agent of hydrophilic group, it is easy to absorb moisture from the environment, the water in the plastic surface to form a single molecule of conductive layer (
Such as antistatic agent for ionic compounds, but also have the effect of ion conductive)
, thereby reducing the surface resistance and leakage of accelerating charge;
, on the other hand, due to the plastic surface layer of molecules with antistatic agent and the adsorption of water, so the friction when the friction between the permittivity of the dielectric constant of air significantly high, thereby weakening the clearance of the electric field intensity, reduce the produce of the charge.
Internal function mechanism of the antistatic agent is antistatic agent in the process of resin is added to the resin composition of the surface active agent, compatibility between it and the resin with moderate, and the resin has good mix capacitive, but does not fully compatible, molding process and molding, antistatic agent will gradually migrate to the surface from inside the plastic products.
When adding antistatic agent quantity is high enough,
Add in general for every 100 resin, add 0.
3 copies of internal antistatic agent)
-, internal antistatic agent in the resin
The arrangement of air interface to form the most densely populated, the polarity of the antistatic agent,
All toward air side is arranged to form a single molecular conductive layer, which showed an antistatic property.
Theoretically, as long as on the surface of plastic film to form a single molecular conductive layer, which can produce a good antistatic effect, but the actual test surface, antistatic need migration accumulation on the surface of the plastic antistatic agent amount, far higher than the single molecule layer, covering the surface of the plastic antistatic molecular average for more than ten layers, in order to show the ideal effect of antistatic.
The amount of adding antistatic agent of the people to reach a critical concentration, with the increment of antistatic agent to add people, plastic antistatic ability will be improved obviously, for general polymer compound, critical concentration is about 0.
5 * 10 (
Due to internal antistatic agent in the resin distribution is not uniform, the surface concentration is high, the internal concentration is low, antistatic effect like external antistatic agent, still rely on them within the resin on the surface of the antistatic agent of molecular conductive layer, if due to causes such as tension, friction, washing antistatic agent on the surface of resin molecular layer defect, film antistatic property and reduces, but the inside of the resin antistatic agent molecules will continue to migrate to the surface, the surface defect of the antistatic agent of molecular layer from the inside to get and make the antistatic ability gradually restored.
Therefore, generally speaking, the durability of the antistatic agent internal external antistatic agent is much better.