Factors affecting the antistatic effect of plastics

The function of antistatic agents is to reduce their surface resistance. Reduce or eliminate electrostatic charge on plastic surfaces. Therefore, the antistatic effect of plastics is affected by many factors.

For the internal mixing type, the compatibility between the antistatic agent and the plastic directly affects the antistatic performance of the plastic. If the compatibility is too good, it will be difficult for the antistatic agent molecules to migrate due to intermolecular attraction; if the compatibility is too poor, the antistatic agent will quickly precipitate on the surface, causing excessive bleeding, which not only affects the appearance and processability of the product, but also shortens the antistatic validity period. Therefore, in actual use, antistatic agents and plastics must have moderate compatibility.

When the surface antistatic agent is depleted, the internal antistatic molecules can seep out of the surface in time to restore the antistatic effect. Generally, ionic antistatic agents should be used for polar resins, and non-ionic antistatic agents with low polarity should be used for weak or non-polarizing resins.

The glass transition temperature (T) of plastic directly affects the migration speed of antistatic molecules. For plastics below room temperature, due to the strong movement of the linking molecules, it is conducive to the surface migration of internal antistatic agent molecules. For example, the antistatic properties of PE, PP and other plastics are easier to maintain, while for some plastics above room temperature, such as PS, PVC, ABS, etc. Because its molecular chains are already in a frozen state, it is difficult for antistatic agents to migrate to the surface.

The interaction between antistatic agents and other plastic agents will also affect the performance of their antistatic properties. Such as adding antistatic agent and lubricant at the same time. The interaction between antistatic agents and halogen-free flame retardants must be considered when combining them. In addition, the crystallinity of plastics, the amount of antistatic agent added, and many external factors, especially the relative temperature of the environment, have varying degrees of impact on the antistatic effect of plastics.