How to Choose Chemical Raw Materials for Insulation Materials in Electrical Engineering: Answers to Frequently Asked Questions

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The production of insulating materials for electrical engineering requires careful selection of chemical raw materials that must meet demanding requirements for electrical strength, temperature resistance, and long-term stability. Whether it involves resins for encapsulating electronic modules, insulating varnishes for motor windings, or thermoplastics for high-voltage applications, each raw material plays a crucial role in the final properties of the product. In this article, we will focus on the most common questions manufacturers address when selecting and processing these materials—from the influence of additives on electrical properties to ensuring compliance with REACH and CLP regulations.

1. What Properties Must Chemical Raw Materials for Insulation in Electrical Engineering Have?

Insulating materials in electrical engineering must meet strict requirements for dielectric strength, thermal resistance, and mechanical stability. A key property is high dielectric strength, which determines the material's ability to withstand electrical breakdown. Typically, values in the range of tens of kV/mm are required, with specific demands depending on the application – for example, high-voltage cables require higher values than low-voltage components. Thermal resistance is also important, as insulating materials must function long-term in a range from -40 °C to 180 °C (depending on the insulation class). For special applications, such as motors or transformers, resistance to thermal aging and oxidative processes is additionally required.

Other critical parameters include low moisture absorption and chemical stability. Moisture can significantly reduce insulating properties, which is why hydrophobic additives or materials with a closed-cell structure are often used. Chemical resistance is particularly important in environments with aggressive substances, such as oils, solvents, or acids. For dynamic applications, such as in rotating machines, mechanical strength and vibration resistance are also essential. The selection of raw materials must therefore always consider the specific operating conditions and standards, such as REACH or directives for electromagnetic compatibility.

2. What types of chemical raw materials are used for the production of insulating materials?

In electrical engineering, polymers, resins, and special additives are most commonly used for the production of insulating materials. Among the most widespread are epoxy resins, which excel in high dielectric strength and mechanical resistance. They are used, for example, for encapsulating electronic components or manufacturing insulating boards. Polyurethanes and silicones are other popular materials, particularly for applications requiring flexibility and resistance to extreme temperatures. Silicones also exhibit excellent hydrophobic properties, making them ideal for outdoor applications or environments with high humidity.

For thermoplastic insulating materials, polyethylene (PE), polypropylene (PP), or polyvinyl chloride (PVC) are often chosen, which are characterized by easy processability and low cost. High-temperature applications then require materials such as polyetheretherketone (PEEK) or polyimide, which withstand temperatures above 200 °C. To improve properties, additives are added to the base raw materials, for example, flame retardants (based on bromine or phosphorus), UV stabilizers, or fillers such as glass fibers to increase mechanical strength. The selection of a specific raw material depends on the required properties and technological processing possibilities.

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3. How does the selection of raw materials affect the lifespan and reliability of insulating materials?

The service life of insulating material is directly dependent on the quality and compatibility of the chemical raw materials used. For example, an incorrectly chosen additive can accelerate polymer degradation due to heat, UV radiation, or chemicals, leading to cracking, loss of elasticity, or reduced dielectric strength. A typical example is the use of an unsuitable plasticizer in PVC, which evaporates over time and causes material brittleness. Similarly, insufficient resistance to oxidation can lead to the formation of conductive paths on the insulator's surface, increasing the risk of electrical breakdown.

The reliability of insulating material is also influenced by its ability to withstand mechanical stress, such as vibration or cyclic loading. Materials with low strength may deform or crack over time, compromising insulating properties. Another important factor is thermal stability—materials that decompose or release corrosive substances at operating temperatures can damage surrounding components. For long-term reliability, it is therefore essential to select raw materials with proven resistance to all relevant influences and to perform accelerated aging according to standard test methods.

4. What are the most common mistakes when selecting raw materials and how to avoid them?

One of the most common mistakes is underestimating the impact of operating conditions on insulating material. For instance, selecting a raw material based solely on dielectric strength without considering temperature resistance can lead to premature failure in applications with high thermal loads. Similarly, ignoring chemical resistance can cause material degradation in environments with oils or solvents. The solution is to always conduct a thorough analysis of application requirements and consult raw material selection with experts who understand material behavior under real-world conditions.

Another common mistake is insufficient testing of raw material compatibility, especially when combining various additives or fillers. For example, some flame retardants can negatively affect the mechanical properties of a polymer or increase its flammability. Therefore, it is essential to conduct comprehensive testing before final selection, including dielectric strength tests, thermal aging tests, and mechanical resistance tests. It is also important to follow the recommendations of raw material manufacturers and certifications according to applicable standards, such as REACH or CLP, which ensure the safety and quality of materials.

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How to assess the compatibility of chemical raw materials with the required electrical properties?

The selection of chemical raw materials for insulating materials in electrical engineering requires careful evaluation of their electrical properties, particularly dielectric strength, resistivity, and loss factor. Dielectric strength determines the maximum voltage a material can withstand without breakdown – for high-voltage applications, raw materials with high values, such as epoxy resins or polyimides, are key. Resistivity then influences the leakage current, which should be as low as possible to prevent undesirable energy losses. The loss factor (tan δ) indicates how efficiently the material transmits electrical energy without converting it into heat, which is crucial for high-frequency applications.

To verify the compatibility of raw materials with the required parameters, it is essential to conduct standard electrical tests, such as measuring insulation resistance or breakdown voltage tests. The results of these tests must be compared with the technical requirements of the specific application. It is also important to consider the influence of temperature and humidity, which can significantly degrade electrical properties. For example, polyamides or polyester resins may lose their insulating capabilities at high humidity, whereas silicones retain their properties even under extreme conditions.

What certifications and standards should raw materials for electrical insulating materials meet?

Raw materials intended for insulating materials in electrical engineering must meet strict safety and quality standards to ensure their reliability and long-term functionality. A fundamental requirement is registration under the REACH regulation, which governs the use of chemical substances in the EU and ensures their safe application. Furthermore, it is crucial that raw materials comply with the classification under the CLP/GHS regulation, which defines their hazardousness and ensures proper labeling and handling.

For electrical engineering applications, specific certifications are often required, such as compliance with flammability standards (e.g., UL 94 for plastics) or resistance to electric arcing. These certifications confirm that the material can withstand extreme conditions, such as high temperatures or electrical discharges, without degradation or ignition. When selecting raw materials, it is also important to verify whether the manufacturer provides technical data sheets with detailed information on electrical, mechanical, and thermal properties, enabling an accurate assessment of suitability for the specific application.

How to Optimize Costs When Selecting Raw Materials Without Compromising Performance?

Optimizing costs when selecting chemical raw materials for insulating materials in electrical engineering requires a comprehensive approach that considers not only the purchase price but also the total lifecycle costs of the material. One effective way to reduce costs is to choose raw materials with high processability, enabling faster and more energy-efficient production. For example, low-viscosity liquid epoxy resins can shorten processing time and reduce energy consumption during casting or impregnation.

Another key factor is the lifespan and maintenance of the insulating material. Raw materials with high resistance to temperature fluctuations, chemicals, or mechanical stress can reduce the need for frequent replacements and repairs, thereby lowering operating costs in the long term. In some cases, it may be advantageous to invest in premium raw materials, such as fluoropolymers or silicones, which, despite their higher purchase price, offer excellent properties that extend the product's lifespan and minimize the risk of failure. It is also important to consider the possibilities of recycling or reusing materials, which can provide additional savings.

Need advice on selecting raw materials?

Every application requires an individual approach – that is why we provide detailed technical data sheets and safety data sheets (SDS) for each chemical raw material. Our experts will be happy to help you select materials tailored to your requirements for insulating properties, temperature resistance, or processability. Contact us – or browse our catalog of over 1,300 products right away.