How to Choose Additives for Coatings and Inks: Key Parameters and Practical Testing

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Additives often play an underappreciated but crucial role in coatings and inks. Even a small amount of the right additive can significantly improve spreadability, resistance to settling, gloss, weather resistance, or even shorten drying time. Conversely, the wrong choice can lead to defects such as bubbles, cracks, or uneven coverage. Selecting additives is not just about chemical composition—it also depends on the specific application, processing conditions, and desired properties of the final product. How can you navigate the range of additives, and what should you test before implementing them in production?

1. Basic Types of Additives for Coatings and Inks

Additives for paints and inks perform a number of key functions that affect both the properties of the product itself and its processability and final appearance. The most common categories include dispersing agents, which ensure uniform dispersion of pigments and fillers, thereby preventing sedimentation and improving colour stability. To adjust rheological properties, thickeners and viscosity modifiers are used, which optimise flow and application of the coating, whether by brush, roller or spraying technique. Defoamers are essential to prevent foaming and bubble formation, while wetting agents improve adhesion to the substrate and even spreading of the coating.

Another important group consists of additives to improve resistance, such as UV stabilisers, which protect the coating from degradation due to sunlight, or anti-corrosion additives for metal surfaces. For inks, specific additives are used to adjust drying speed, abrasion resistance or compatibility with different printing technologies (e.g. inks for digital printing vs. flexographic printing). The selection of the right type of additive depends on the specific application, substrate and desired properties of the final product, such as gloss, mattness, chemical resistance or mechanical strength.

2. Key Selection Parameters: What to Look for in a Supplier

When selecting a supplier of additives for paints and inks, it is crucial to verify several technical and qualitative parameters. The first criterion is the compatibility of the additive with the raw materials used – for example, with binders, solvents or pigments. The supplier should provide detailed technical data sheets with information on chemical stability, pH range, temperature resistance and possible interactions with other components of the formulation. It is also important to verify whether the additives meet safety and legislative requirements, particularly REACH and CLP/GHS regulations, which govern the classification, labelling and packaging of chemical substances.

Another factor is the consistency of quality and the availability of technical support. A reliable supplier should guarantee stable properties of their products across batches and offer support in solving issues such as component separation, changes in viscosity, or loss of additive effectiveness. It is also advisable to verify whether the supplier conducts their own testing and develops new solutions, which can be an advantage for innovative applications. Price should not be the only deciding criterion—low prices may imply compromises in quality or insufficient technical support.

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3. Practical testing of additives: Methods and recommended procedures

Testing additives under laboratory and pilot-scale conditions is essential to verify their effectiveness and compatibility with a specific formulation. The basic step involves preparing test samples with varying concentrations of the additive, which are then evaluated using standard test methods. For dispersing agents, for example, the degree of pigment dispersion is monitored by measuring particle size or conducting sedimentation tests. For thickeners, viscosity and rheological behavior are assessed using rotational viscometers or rheometers.

To verify coating durability, tests such as resistance to UV radiation (accelerated aging), chemical resistance (e.g., to solvents or acids), or mechanical properties (abrasion resistance, flexibility, or impact resistance) are performed. For inks, key tests include adhesion to various substrates, drying speed, and abrasion resistance. It is also recommended to conduct tests under real-world conditions, such as applying the coating to material samples that will be used in practice. Test results should be documented and compared with reference samples without additives or with competitive products.

4. Formulation Optimization: How to Achieve the Desired Properties

Optimizing the formulation of coatings or inks with additives requires a systematic approach and often several iterations of testing. The first step is defining the desired properties of the final product, such as gloss, matte finish, weather resistance, or mechanical strength. Based on these requirements, suitable additives and their concentrations are selected, while also considering the interactions between individual components. For example, a combination of a dispersing agent and a thickener can affect both pigment stability and the viscosity of the coating.

When optimizing, it is advisable to proceed in small steps and monitor the impact of each change on the product's properties. For example, increasing the concentration of a UV stabilizer may improve resistance to degradation but can simultaneously affect the color or gloss of the coating. It is also important to test the long-term stability of the formulation, for instance by storing samples at different temperatures and observing any changes in viscosity, separation, or loss of additive efficacy. Collaboration with an additive supplier that offers technical support and know-how can significantly accelerate the optimization process and yield better results than independent experimentation.

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Impact of Additives on Ecological and Safety Parameters of Coatings and Inks

Selecting additives for coatings and inks today is not just a question of technical efficiency, but also ecological and safety compatibility. Modern manufacturing processes and legislation (e.g., REACH or CLP/GHS regulations) emphasize minimizing risks associated with volatile organic compound (VOC) content, allergens, or toxic components. Additives such as plasticizers, antistatic agents, or biocides must be evaluated not only in terms of functionality but also their impact on the environment and user health. For example, replacing phthalate-based plasticizers with biobased alternatives can reduce VOC emissions by tens of percent without losing the coating's elasticity.

Another important aspect is the compatibility of additives with certifications such as Ecolabel or Blue Angel, which require documentation of raw material origin and biodegradability. When selecting a supplier, it is therefore crucial to verify whether they provide transparent safety data sheets (SDS) and certificates of conformity. Eco-friendly additives often bring additional benefits, such as reduced odor or improved processability under industrial conditions. Investing in "green" additives can thus pay off in the long term, not only in terms of legislation but also brand image.

Economic Aspects of Additive Selection: Costs vs. Added Value

When optimizing costs for coatings and inks, it is tempting to focus on the price of additives as the primary criterion. However, this approach may lead to underestimating the long-term savings that high-quality additives provide. For example, using more effective dispersing agents can reduce the required dosage by 20–30%, which compensates for the higher purchase price. Similarly, additives that enhance resistance to UV radiation or chemicals extend the coating's lifespan, thereby reducing maintenance and repair costs.

A key tool for economic evaluation is testing under real-world conditions, which reveals the true effectiveness of the additive. For example, additives to improve spreadability can reduce material consumption by 5–15 % thanks to more even application. When selecting a supplier, it is therefore important to consider not only the price per kilogram, but also the recommended dosage, stability in the formulation, and technical support. Suppliers offering comprehensive analyses and samples for testing enable more accurate calculation of return on investment.

Trends and Innovations in Coatings and Inks Additives

The field of coatings and inks additives is undergoing dynamic development, reflecting demands for sustainability, digitalisation, and multifunctionality. One of the main trends is the development of additives based on renewable raw materials, such as vegetable oils or waste biomass, which replace traditional petrochemical products. These innovations not only reduce the carbon footprint but often also provide better technical properties, such as higher resistance to weathering.

Another significant direction is the integration of additives with smart functionalities, such as self-cleaning surfaces (utilising photocatalytic effects) or coatings with thermochromic properties that change colour depending on temperature. In the field of inks, demand is growing for additives that increase resistance to abrasion and chemicals, which is crucial for industrial printing or packaging. When selecting a supplier, it is therefore advisable to monitor their investments in research and development, which may indicate their ability to deliver innovative solutions tailored to future market requirements.

Need Help Choosing Additives?

Every additive in our portfolio is accompanied by a detailed technical data sheet and safety data sheet (SDS). Our experts will be happy to advise you on the selection and optimization of formulations for your specific needs. Contact us – or browse our catalog of over 1,300 products right away.