How to Apply Antistatic Agents in Electrical

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Plastic components in electrical engineering are often exposed to the risk of static electricity buildup, which can damage sensitive electronic components or cause dangerous discharges. Antistatic additives solve these problems, but their effectiveness depends on proper application. In this article, we will guide you step-by-step on how to prepare the material, select the appropriate additive, and ensure its even distribution in the plastic matrix. The correct procedure minimizes the risk of failure and extends the lifespan of the final products.

1. Selecting the Right Antistatic Additive Based on Plastic Type and Application

The correct selection of an antistatic additive is fundamental to achieving the desired properties of a plastic component. In electrical engineering, internal (integral) antistatics are most commonly used, which are added directly to the polymer matrix during processing. Among the most widespread are quaternary ammonium salts, alkyl sulfonates, or ethoxylated amines, which reduce the surface resistance of the plastic to values between 10^9 and 10^12 Ω. The choice of a specific substance depends on the type of polymer – for example, ethoxylated amines are suitable for polyolefins (PP, PE), while quaternary ammonium compounds are more frequently used for engineering plastics such as PA or PC.

It is also important to consider the requirements of the specific application. For components exposed to high temperatures (e.g., in engines or transformers), thermally stable additives that do not evaporate during processing are suitable. Conversely, for components requiring long-term antistatic effectiveness (e.g., packaging for electronics), substances with low migration are chosen. Always verify the compatibility of the additive with the polymer and other additives in the formulation to avoid issues with material degradation or loss of mechanical properties.

2. Material Preparation and Antistatic Additive Dosage

Before processing, it is necessary to thoroughly dry the plastic material, especially for hygroscopic polymers such as PA or PET. Moisture in the material can negatively affect the dispersion of the additive and reduce its effectiveness. Drying at temperatures of 80–120 °C for 2–4 hours is recommended, depending on the polymer type and granule thickness. For precise dosing of the antistatic agent, it is ideal to use gravimetric dosing equipment, which ensures even distribution of the additive throughout the entire material volume.

The dosage of the antistatic additive typically ranges from 0.1–3 % by weight, with the optimal amount depending on the desired level of antistatic protection and the type of polymer. Too low a concentration will not achieve the desired effect, while too high a concentration may lead to migration of the additive to the surface, causing stickiness or deterioration of mechanical properties. To determine the precise dosage, it is advisable to conduct test series with varying concentrations and verify the surface resistance using standard test methods.

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3. Processing plastics with antistatic additives: Temperature and technological parameters

The processing temperature has a fundamental impact on the effectiveness of the antistatic additive. Excessively high temperatures can cause degradation of the additive, while temperatures that are too low lead to insufficient dispersion in the polymer matrix. For most thermoplastics, processing in the range of 180–260 °C is recommended, with the specific temperature depending on the type of polymer and the additive used. For example, polypropylene (PP) is typically processed at temperatures of 200–240 °C, while polyamide (PA) is processed at 240–280 °C.

Another important parameter is the processing time. If the material remains in the plasticizing screw for too long, it can lead to degradation of the additive, whereas a short processing time will not ensure its uniform dispersion. The optimal time depends on the machine design and the type of additive but generally ranges between 1–3 minutes. To achieve the best possible dispersion, it is advisable to use a screw with a high shear effect or add a compatibilizer to improve the miscibility of the additive with the polymer.

4. Quality Control and Long-Term Stability of the Antistatic Effect

After processing, it is essential to verify the antistatic properties of the finished product. The most common method is measuring surface resistance according to applicable standards, which should achieve values below 10^12 Ω for effective antistatic protection. For more precise evaluation, tests for dust resistance or electrostatic discharge simulation can also be used. For critical applications (e.g., components for medical technology), long-term stability tests are recommended, where the product is exposed to various conditions (humidity, temperature) and the change in surface resistance over time is monitored.

The long-term stability of the antistatic effect depends on the type of additive and the conditions to which the product is exposed. Migrating antistats (e.g., ethoxylated amines) gradually evaporate to the surface, which can lead to a loss of effectiveness after several months. For applications requiring long-term protection, non-migrating additives (e.g., conductive carbon black or special polymers) are therefore recommended, as they ensure stable properties throughout the product's lifespan. Always consider the influence of other factors, such as surface cleaning or mechanical stress, which can weaken the antistatic effect.

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Optimizing the mixing and homogenization of antistatic additives in the melt

Uniform dispersion of the antistatic additive in the plastic matrix is crucial for achieving consistent properties of the final product. When mixing in the melt, attention must be paid to the correct intensity and duration of mixing, which depends on the type of equipment used (e.g., single-screw vs. twin-screw extruder) and the melt viscosity. Generally, higher temperatures reduce viscosity and facilitate additive distribution but also increase the risk of polymer or antistatic agent degradation. It is recommended to start with lower screw speeds (30–60 rpm) and gradually increase to the optimal value, ensuring sufficient homogenization without excessive material stress.

To achieve the best possible homogeneity, it is advisable to use a masterbatch or a pre-prepared mixture of the antistatic additive with a carrier polymer. This minimizes the risk of particle agglomeration and improves dispersion in the melt. For some types of antistatic agents (e.g., ionic liquids), it may be necessary to add a compatibilizer to enhance their bonding with the polymer matrix. Homogeneity is checked using standard test methods, such as microscopic analysis of sample cross-sections or surface resistance measurements at different points on the product.

Impact of Processing Conditions on the Migration of Antistatic Additives to the Surface

The antistatic effect of most additives depends on their ability to migrate to the surface of the plastic part, where they form a thin conductive layer. This process is strongly influenced by processing conditions, particularly temperature and cooling time. If cooling is too rapid (e.g., in a water bath), the antistatic additive may become "frozen" inside the material, significantly reducing its effectiveness. Conversely, slow cooling in air or a temperature-controlled environment allows the additive to gradually diffuse to the surface and form a uniform layer.

Another important factor is the pressure during processing. High pressure in the tool (e.g., during injection molding) can slow down the migration of the additive, while low pressure or vacuum degassing, on the other hand, accelerates migration. For some applications, such as electronic device housings, it is recommended to perform additional annealing after processing (e.g., at 60–80 °C for 24–48 hours) to promote the even distribution of the antistatic layer. This step is particularly important for materials with high crystallinity, where additive migration occurs more slowly.

Solutions to Common Problems in the Application of Antistatic Additives

Various issues may arise during the application of antistatic additives, negatively affecting the quality of the final product. One of the most common is insufficient antistatic effect, which can be caused by poor additive selection, insufficient dosage, or inadequate homogenization. In such cases, it is necessary to verify the compatibility of the additive with the polymer used and check processing parameters, particularly temperature and mixing time. For some polymers (e.g., polyolefins), it may be necessary to increase the additive dosage by 10–20% above the recommended amount.

Another frequent issue is the deterioration of the plastic’s mechanical properties, such as reduced strength or impact toughness. This can be caused by excessive dosing of the antistatic additive or its negative impact on the polymer structure. The solution is to reduce the additive concentration and, if necessary, add modifiers to improve mechanical properties. In transparent applications, haze or color changes may occur, usually indicating incompatibility of the additive with the polymer or its degradation at high temperatures. In such cases, it is advisable to choose a different antistatic additive or adjust the processing conditions.

Need help selecting antistatic additives?

Every application requires an individual approach – GCG Group provides detailed technical data sheets and safety documentation (SDS) for the supplied raw materials and assists in selecting the appropriate type of antistatic additive based on your material and production process requirements. Contact us – or browse our catalogue of over 1,300 products.