Introduction and Applications of Antistatic Coatings

Electrostatic dissipative coatings are a type of functional coating with specific conductive properties. Their primary function is to rapidly and safely discharge static electric charges generated or accumulated on the surface of objects by reducing the surface resistance of the coating, thereby mitigating risks such as fires, explosions, or equipment malfunctions caused by electrostatic discharge. These coatings are widely used in environments where flammable and explosive substances are present or where sensitivity to static electricity is a concern.

I. Core Characteristics of Antistatic Coatings

The performance of antistatic coatings is primarily evaluated based on the following key indicators, which also represent their core distinguishing features from conventional coatings:

• Surface resistance This is the most critical performance indicator; typically, the surface resistivity of the coating should be within 10. ⁵ ~10 ⁹ Ω, for example: The surface resistivity of the antistatic coating applied to the inner wall of oil tanks must be less than 1.0 × 10. ⁹ Ω, the volume resistivity should be less than 1.0 × 10. ⁸ Ω·cm.

• Conductive stability The coating’s conductive performance must remain stable over the long term and be unaffected by environmental factors such as temperature, humidity, medium corrosion, friction, and wear, thereby preventing “loss of conductivity” during use.

II. Main Application Scenarios for Antistatic Coatings

1. Tank and Vessel Industry

This is one of the most critical application scenarios for antistatic coatings, particularly for equipment used to store flammable and explosive media:

• Applicable devices Liquid storage tanks for gasoline, diesel, ethanol, solvents (such as methanol and acetone), as well as gas storage tanks for liquefied petroleum gas (LPG) and natural gas.

• Principle of operation During the loading, unloading, and mixing of materials in storage tanks, friction between the medium and the tank walls can easily generate static electricity. If a non-conductive lining or ordinary coating is used, static charges will continue to accumulate. Conductive anti-static coatings, however, can safely conduct these charges to the grounding system, thereby preventing static discharge from igniting the medium.

Inner wall of steel storage tank

2. Transportation sector

Primarily used as a carrier for transporting flammable and explosive goods, it prevents accidents caused by static electricity during transportation.

• Applicable carrier Tank trucks (including tank bodies and internal linings), liquefied natural gas transport tankers, and hazardous material transport containers.

• Key requirements In addition to antistatic properties, the coating must also exhibit resistance to impact and abrasion as well as oil permeation resistance, ensuring that the coating remains intact and its conductive performance does not degrade during long-term transportation.

Pipeline lining

3. Electronics and Precision Manufacturing Industry

For electrostatic-sensitive electronic components, avoid static damage to equipment or impairment of product quality:

• Applicable scenarios Electronic factory floors, equipment housings (such as those for semiconductor manufacturing equipment), and circuit board handling containers.

• Performance requirements It must meet the “low static voltage” requirement (typically kept below 50V). At the same time, the coating must possess dust-resistant and cleanable properties (capable of withstanding wiping with cleaning agents such as alcohol) to prevent contamination of electronic components.

4. Chemical and Pharmaceutical Industry

Equipment that comes into contact with flammable, explosive, or electrostatic-sensitive media during the production process:

• Applicable devices Reactor vessels (with internal linings), conveying pipelines (especially those used for solvents and resins), and dust collection hoppers in the pharmaceutical industry (where friction between dust and hopper walls can easily generate static electricity).

• Specially adapted The corrosion-resistant, antistatic coating (such as acid-resistant or alkali-resistant coatings) must be selected based on the chemical properties of the medium to prevent the coating from being corroded by the medium and losing its antistatic function.

III. Key Technologies and Classification of Antistatic Coatings

The conductive performance of antistatic coatings primarily depends on the addition of conductive fillers. Depending on the type of conductive filler and the specific application scenario, they can be categorized into the following main types:

1. Carbon-based antistatic coating

• Core conductive filler Carbon-based materials such as graphite, carbon black, and carbon nanotubes.

• Technical features It exhibits stable electrical conductivity, low cost, and strong compatibility (capable of being combined with various resin systems such as epoxy and polyurethane). However, certain carbon black fillers may affect the coating’s appearance (e.g., causing a darker color), so it is necessary to adjust the formulation to strike a balance between electrical conductivity and aesthetic requirements.

2. Metal-based antistatic coating

• Core conductive filler Metal powders or metal fibers such as copper powder, silver powder, and nickel powder.

• Technical features It boasts high electrical conductivity, and certain metallic fillers can impart a degree of decorative appeal to the coating. However, metallic fillers are prone to oxidation, so their corrosion resistance must be enhanced through surface treatments (such as coating with a passivation layer). As a result, the cost of these coatings is higher than that of carbon-based coatings.

3. Conductive Coating for Composite Systems

• Core conductive filler Combining carbon-based and metal-based fillers (e.g., carbon black + nickel powder) or integrating conductive fillers with inorganic non-metallic fillers.

• Technical features It can integrate the advantages of different fillers—for example, balancing the stability of carbon-based fillers with the high conductivity of metal-based fillers—while leveraging inorganic fillers to enhance the coating’s wear resistance and weatherability. The formulation design is complex and the cost is relatively high.

IV. Major Development Trends

• Eco-friendly As environmental protection policies become increasingly stringent, solvent-based antistatic coatings are gradually transitioning to waterborne and solvent-free formulations. For example, waterborne epoxy antistatic coatings can significantly reduce VOC emissions and have already been applied in settings such as electronic manufacturing facilities and food-grade storage tanks.

• Functional integration In addition to antistatic properties, coatings need to integrate more functionalities, such as “antistatic + ultra-high temperature resistance” (suitable for battery storage tanks in the new energy sector) and “antistatic + antibacterial” (suitable for cleanroom equipment in the pharmaceutical industry).

• Intelligentization Develop a “self-healing antistatic coating” by incorporating microcapsule-based repair agents. When tiny cracks appear in the coating, the microcapsules rupture and release the repair agents, automatically sealing the cracks and maintaining continuous electrical conductivity. At the same time, explore “online monitoring of conductive performance” technology: by embedding sensors, continuously monitor changes in the coating’s resistance in real time to promptly warn of potential failure risks.