How to Choose Adhesive or Sealant Based on Materials and Application Conditions: A Guide for Industrial Manufacturers

Photo: Aditi Toys / Unsplash

Choosing an adhesive or sealant for industrial joints is not just a matter of price, but primarily about compatibility with materials and operating conditions. The wrong choice can lead to joint failure, loss of strength, or even product damage. Key parameters such as adhesion to different surfaces, resistance to temperature, humidity, or chemicals, as well as mechanical properties (e.g., flexibility vs. rigidity) determine whether the product will withstand the required load. This article will help you navigate the selection criteria and avoid common mistakes that increase production costs or compromise quality.

Basic Types of Adhesives and Sealants: How to Navigate the Offer

Choosing the right adhesive or sealant starts with understanding the basic categories and their properties. Adhesives are divided into physically setting (e.g., dispersion, hot-melt, or contact adhesives), chemically curing (epoxies, polyurethanes, acrylates), and special types (e.g., anaerobic or UV adhesives). Sealants include silicone, polysulphide, polyurethane, or acrylate variants, each with different elasticity, temperature resistance, or chemical resistance. A key criterion is the curing method: while physically setting adhesives dry by solvent evaporation or cooling, chemically curing adhesives react to moisture, heat, or UV radiation and form stronger bonds.

For industrial applications, the mechanical resistance of the bond is also crucial. For example, epoxy adhesives excel in high strength and temperature resistance (up to 200 °C) but are brittle. Polyurethane adhesives and sealants, on the other hand, offer flexibility and vibration resistance, making them ideal for bonding materials with different thermal expansion coefficients (e.g., metal and plastic). When selecting an adhesive, working conditions must also be considered: some adhesives require precise dosing and mixing, while others are sensitive to moisture or dust during application.

Materials and their specific requirements: What are you bonding?

Different materials require different bonding approaches. Metal surfaces (steel, aluminium) often need adhesives with high strength and temperature resistance, such as epoxies or anaerobic adhesives. Plastics are divided into easily bondable (PVC, polycarbonate) and difficult-to-bond (polyethylene, polypropylene), where surface pretreatment (plasma treatment, chemical primers) or special adhesives based on cyanoacrylates or polyurethanes are necessary. Glass requires transparent bonds with UV resistance, which is why UV adhesives or silicone sealants are often used.

In composite materials (fiberglass, carbon fibers), compatibility with the matrix is key – for example, epoxy adhesives work well with epoxy resins in composites. Wood and paper require adhesives with good penetration and fast setting, such as dispersion or hot-melt adhesives. When bonding different materials (e.g., metal + plastic), it is necessary to choose an adhesive that compensates for differences in thermal expansion and mechanical stress, such as flexible polyurethane systems.

Photo: Homa Appliances / Unsplash

Application conditions and operating environment: What must the adhesive withstand?

Operating conditions significantly influence the selection of adhesives or sealants. In exterior applications, resistance to UV radiation, moisture, and temperature fluctuations is critical – silicone or polysulfide sealants and special epoxies with UV stabilizers perform well here. In industrial environments with high temperatures (above 150 °C), ceramic adhesives or silicone systems are suitable, while for refrigeration applications (below -20 °C), polyurethane or special low-temperature flexible epoxy adhesives are used.

Chemical resistance is crucial in the food, pharmaceutical, or chemical industries, where adhesives must comply with REACH standards and resist acids, alkalis, or solvents. For vibrational stress (e.g., in the automotive industry), flexible polyurethane or MS polymer sealants are ideal. Processing time is also an important factor: fast-curing adhesives (cyanoacrylates, UV adhesives) shorten production cycles but require precise application. Conversely, two-component adhesives allow for longer processing times but require mixing and accurate dosing.

How to Choose a Supplier and What to Watch Out For

The right supplier of chemical raw materials should offer not only a wide range of adhesives and sealants but also technical support and test samples. Look for a partner who understands your industry and can recommend tailored solutions – for example, for the automotive industry, construction, or electronics. Certification of products according to current standards (REACH, CLP/GHS) and the availability of safety data sheets are also important. Experienced suppliers also provide training for adhesive application and processing, which minimizes the risk of errors in production.

When selecting a supplier, also consider logistical capabilities such as delivery speed, availability of stock, and flexibility in orders. For specialized applications, collaboration with a supplier offering in-house development laboratories for testing and formula customization is advantageous. Do not forget the economic aspects either: the price per kilogram is not the only criterion—yield, joint durability, and application costs (e.g., the need for surface pretreatment or special equipment) are also important.

Photo: TruckRun / Unsplash

Mechanical stress and joint durability: How to account for load and service life

When selecting an adhesive or sealant, it is crucial to consider the type of mechanical stress the joint will be exposed to. Static loads, such as the dead weight of a structure, require adhesives with high tensile and shear strength, such as epoxy or polyurethane systems. These materials achieve strengths of up to 30 MPa and are suitable for metal or composite joints in mechanical engineering or construction. Conversely, dynamic stresses, such as vibrations or repeated impacts, require flexible adhesives with high fatigue resistance, such as modified acrylates or silicone sealants.

The lifespan of a joint depends not only on the type of adhesive but also on its compatibility with the substrate and operating conditions. For example, cyanoacrylate-based adhesives cure quickly but have limited resistance to moisture and temperature fluctuations. For long-term applications in outdoor or humid environments, polyurethane or MS polymer sealants are more suitable, as they retain their elasticity and strength even after years. Always verify whether the manufacturer declares resistance to creep and material fatigue according to standard test methods.

Application Technology and Processability: How to Optimize the Manufacturing Process

The choice of adhesive or sealant is closely linked to the application technology and processability requirements. Manual application requires products with a longer open time and easy processability, such as low-viscosity two-component epoxies or one-component polyurethane sealants. In contrast, automated lines with robotic application need adhesives with precisely defined viscosity, rapid curing, and minimal shrinkage, such as UV-curable acrylates or heat-activated systems.

An important factor is also the temperature and humidity during application. Some adhesives, such as anaerobic or cyanoacrylate adhesives, require specific conditions for optimal curing. Polyurethane sealants, on the other hand, can react with atmospheric moisture, which affects their workability and curing time. Before deploying in production, always conduct compatibility tests with your equipment and verify whether the supplier provides technical support for process optimization. Also, pay attention to safety – some adhesives contain volatile organic compounds (VOCs) or require personal protective equipment.

Ecological and Safety Aspects: How to Meet Legislative Requirements and Sustainability

The selection of an adhesive or sealant must take into account not only technical parameters but also ecological and safety requirements. The REACH and CLP/GHS regulations set obligations for the classification, labelling, and packaging of chemical substances, including adhesives. For example, epoxy systems often contain substances classified as sensitising or toxic, which require special measures during handling and storage. Conversely, water-based adhesives or products based on natural resins may be more environmentally friendly and safer for workers' health.

Sustainability is becoming an increasingly important criterion, especially in the automotive, furniture, or construction industries. Look for suppliers who offer adhesives with low VOC content, phthalate-free products, or those with certification for recyclable materials. Some modern systems, such as bio-based polyurethanes or adhesives based on vegetable oils, combine high performance with an ecological profile. Before selecting a product, verify whether the supplier provides safety data sheets (SDS) and technical documentation in compliance with current legislation, and whether they can advise on optimizing the process in terms of safety and sustainability.

Need help with your selection?

Every adhesive or sealant in the GCG Group portfolio is accompanied by detailed technical data sheets and safety data sheets (SDS), which contain all the necessary information for correct application. Our experts will be happy to advise you on selecting a product tailored precisely to your materials and operating conditions. Contact us – or browse our catalogue of over 1,300 products right away.