Currently, an additive anti-static masterbatch is used in a limited number of polymers, mainly polyethylene and polypropylene (film, sheet, injection molded products, containers, and especially packaging materials). Applications for polyvinyl chloride (e.g., discography) are relatively low because estimates of the application in this area are still divergent.
1. Anti-static masterbatch applied in vinyl polymers
In recent years, the application of anti-static masterbatch in styrene polymers (polystyrene, impact-resistant polystyrene) has been increasing. Unlike polyolefins, the dosage of antistatic agents in these substrates must be as high as 4% for good activity. Thus, with the exception of special products such as video casings, instrument casings, etc., cost factors limit this application.
In what is commonly known as engineering plastics (including polyethylene terephthalate, polycarbonate, and polysulfone) and polyacrylates, additive anti-static masterbatch has not found any use for two main reasons. First, these materials are formed at high, sometimes very high temperatures; Second, many of these materials have important intrinsic properties (such as the transparency of polymethacrylate and polycarbonate) that cannot be compromised under any circumstances.
For products used in environments where there is a risk of fire or explosion, filling with carbon black is increasingly used to obtain high electrical conductivity. For example, packaging materials for explosives, transmission belts for tunnels, and plastic floor materials for public activity places and chemical production plants.
2. The anti-static masterbatch used for packaging materials must be non-toxic
A product that is not harmful to human health is a further requirement for packaging materials coated with anti-static masterbatch. Since there are antistatic molecules on the surface of the plastic, contact with the food it is packaged in is unavoidable. In the case of polyethylene and polypropylene, due to the low content of antistatic agents, it will not cause any serious problems and can meet the requirements of national regulatory bodies on the use of additives.
It is well known that the limits established by these institutions are based on the amount of anti-static masterbatch migration and the analysis of the identified product. Plastics with high anti-static masterbatch, such as styrene polymers, often exceed specified limits. However, some anti-static masterbatches, such as sodium alkyl sulfonate, allow them to be used in special types of plastics, such as crystallized polystyrene, because of their low migration capacity. Other types of plastics (e.g., impact-resistant polystyrene) are prohibited due to excessive migration of anti-static masterbatch.