Internal antistatic

Intermetallics Intermolecular forces Internal antistatic agents Internal conversion Internal energy Internal placticizers... 

The incorporation of metal salts of amphoteric surface active agents (Mostat Series) as internal antistatic agents in polypropylene fibers has been reported (95). Metal salts of alanine, amidoamine, and imida2oiine-type amphoteric surface-active agents show excellent performance as internal antistatic agents and also improve the dyeing abiUty of the fibers with acid dyes. 

There are many commercial surface and internal antistatic additives (136). Table 8 Hsts several of the internal antistats along with the polymers for... 

Table 8. Commercially Available Internal Antistatic Agents and the Polymers for Which They Are Recommended ...

Internal antistats are considered permanent antistats. This permanence is based on the concept that most plastic products are disposable, so that the antistat is not required to last long. The antistatic effectiveness of an internal antistat can decrease over time. One study showed large increases in surface resistivity on antistatic bags stored at 71 °C for six months. Antistatic bags stored at room temperature showed only a small increase in surface resistivity (137). Loss of antistatic effectiveness is attributed to the volatility of the antistatic agent. The antistat does not easily wear off the plastic, but it can be removed with solvents and/or repeated wear. 

H. Mammo, The Internal Antistatic Treatment of Thermoplastic Toljmers, 1st International Congress of Static Electricity, Vienna, Austria, May 3—7, 1970. 

The effectiveness of an internal antistatic agent incorporated in the melt depends primarily on its molecular structure. This determines properties vital to the antistatic effect such as polarity and migration. The aliphatic C)4-C,7 chain in the alkanesulfonates imparts the required migration property to polar plastics, whereas the polar group is responsible for their hygroscopic behav-... 

Alkanesulfonates are preferably used as an internal antistatic agent for plastics, but where incorporation into the polymer is not possible they can be applied to the surface of the finished article in the form of a 1 % aqueous solution of the surfactant by spraying or dipping [99]. 

Alkanesulfonates are widely used as an internal antistatic agent for poly(vinyl chloride) (PVC). Since alkanesulfonates cause hazing of unplasticized PVC in the normally used quantities of 1.0 to 1.5 parts per hundred parts resin (phr), its main use is in the manufacture of opaque PVC-calendered film. To produce transparent unplasticized articles, the addition of alkanesulfonates should not exceed 0.3 phr. Figure 40 shows the antistatic effect of alkanesulfonates in PVC. 

For antistatic modification of extruded and injected-molded articles made from unplasticized PVC, internal antistatic agents are unsuitable in the usual amounts (<2 phr). Instead, the external application of the alkanesulfonates solution mentioned above is recommended. 

Alkanesulfonates are an important internal antistatic agent for polystyrene (PS) as well. If it is not possible to apply the pure active surfactant with the intended processing machine, the use of a master batch of alkanesulfonates and an appropriate polystyrene product is recommended. The addition of alkanesulfonates in amounts greater than 0.3 phr can cause hazing also in transparent PS articles. The antistatic effect of alkanesulfonates in PS is demonstrated in Fig. 41. 

Antistatic agents. Static electrical charges may build up on the surface of polymers due to their low electrical conductivity, which may cause dust accumulation and sparking problems. These charges can be dissipated through the addition of external or internal antistatic agents (phosphate and fatty acid esters, sulfated waxes, quaternary ammonium compounds, amines, etc.). 

RO-8,9,20. [Rogers Anti-Stadc) External coadngs or internal antistats fw plastics. 

Statexan. [MUes/Polysar Rubber] Sul-fonated aliphatic hydrocarbon internal antistat or external coating for PVC, PS. 

Internal antistats are compounded directly into the polymer mix prior to processing. They then migrate slowly and continually through the molecular interstices and the bulk polymer to its surface where they absorb the water necessary to prevent accumulation of static charges. In this case, it is necessary to balance the rate of such migration and the rate of surface removal of the antistat to provide long-term protection for the part. 

Antistats can be appiied internally or externally. Internal antistats are compounded into the resin, and act once they migrate to the surface of the poiymer. External antistats are appiied directly on the surface by spraying, or sometimes by dipping the polymer in a solution of the antistatic. Internal antistatic agents can... 

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