How to Choose Additives for Coatings and Printing Inks: Key Parameters and Practical Testing
The right choice of additives can significantly impact the quality, durability, and application properties of coatings and printing inks. Which parameters should you monitor, and how can you test their effectiveness in real-world conditions?
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Additives in coatings and printing inks often play a key role, despite their minimal share in the overall formulation. They are responsible for the stability of the mixture, improvement of application properties, resistance to external influences, or the aesthetic appearance of the surface. However, selecting the wrong type or dosage can lead to defects such as foam formation, poor adhesion, uneven drying, or reduced resistance to weather conditions. Therefore, it is essential to understand not only the theoretical properties of additives but also their behavior in specific applications. This article focuses on the practical aspects of selecting and testing additives to ensure your products meet customer requirements and regulatory standards.
1. Basic Types of Additives for Coatings and Printing Inks
Additives for coatings and printing inks play a key role in optimizing the properties of final products. Their selection depends on the specific application, required parameters, and processing technology. The most common categories include rheology modifiers, which influence the viscosity and flow of the system. For example, thickeners based on cellulose or synthetic polymers ensure stable consistency, while thinners reduce viscosity for better processability. Another group consists of dispersing agents, which prevent sedimentation of pigments and fillers, thereby improving homogeneity and color stability.
Equally important are additives for modifying surface properties, such as degreasers, wetting agents, or defoamers. These substances eliminate defects like bubble formation, poor adhesion, or uneven spreading. For special applications, additives enhancing resistance to UV radiation, chemicals, or mechanical wear are used. Selecting the right type of additive requires knowledge of chemical compatibility with other system components and the target environment in which the coating or ink will be applied.
2. Key Selection Parameters: What to Consider When Specifying an Additive
When selecting an additive, several technical parameters must be considered that directly affect the performance of the final product. The first criterion is compatibility with the carrier system – the additive must be soluble or dispersible in the solvent or water used without causing undesirable reactions. Furthermore, its impact on viscosity, drying time, and mechanical properties of the coating, such as hardness, flexibility, or abrasion resistance, should be assessed.
Another important factor is the stability of the additive over time and at different temperatures. Some additives may degrade at high temperatures or lose effectiveness during long-term storage. For printing inks, the drying speed and abrasion resistance are also key, while for coatings, weather resistance is often required. It is always advisable to verify whether the additive meets safety and environmental requirements, for example, whether it is registered under the REACH regulation and does not contain prohibited substances.
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3. Practical testing of additives: Methods and recommended procedures
Theoretical knowledge about additives must be verified through practical tests that simulate real-world application conditions. The first step is preparing test samples with varying additive concentrations and comparing them to a reference sample without the additive. To evaluate rheological properties, viscometers or rheometers are used to measure viscosity changes at different shear rates. For printing inks, it is also important to test printing properties such as color transfer to the substrate and print sharpness.
Other key tests include resistance tests against water, chemicals, or UV radiation, which are conducted according to standard testing methods. For example, coatings are often tested for abrasion resistance using abrasive tests or for weather resistance in climate chambers. For additives modifying surface properties, it is advisable to perform wettability and adhesion tests, such as using the contact angle method or cross-hatch test. The results of these tests provide an objective basis for selecting the most suitable additive.
4. How to Choose a Reliable Additive Supplier: Criteria and Tips
Choosing an additive supplier is as important as selecting the product itself. The first criterion should be the technical support and expert advice the supplier offers. A reliable supplier should have in-depth knowledge of their products and their applications to help select the optimal solution for the customer’s specific needs. It is also important to verify whether the supplier has certified laboratories for testing and developing new formulations.
Another factor is the stability of supply and flexibility in orders. The supplier should be able to ensure consistent product quality and deliver the required quantities without unnecessary delays. Last but not least, it is advisable to consider the ecological and safety standards that the supplier adheres to. For example, suppliers registered in the REACH system and complying with CLP/GHS regulations provide a guarantee that their products are safe and legal for use in industrial applications. Before making a final selection, it is recommended to request samples and conduct your own tests to verify the compatibility and performance of additives in the specific application.
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Impact of additives on environmental and safety parameters of coatings and printing inks
The choice of additives significantly influences not only the technical properties of coatings and printing inks but also their impact on the environment and processing safety. Modern formulations increasingly focus on reducing volatile organic compounds (VOC) and replacing traditional additives with more eco-friendly alternatives. For example, biodegradable variants of surfactants are preferred to minimize the burden on wastewater. Similarly, additives for improving spreadability or weather resistance must meet strict REACH and CLP requirements to prevent the release of hazardous substances during application or the service life of the coating.
Safety parameters of additives must be assessed already during the formulation development phase. For instance, corrosion inhibitors based on chromates are gradually being replaced by organic or inorganic alternatives with lower risk due to their toxicity. In printing inks, it is crucial to monitor the content of heavy metals and allergenic substances that may endanger the health of workers or end users. Additive suppliers should provide not only technical data sheets but also safety data sheets with a detailed description of risks and recommendations for safe handling, including information on compatibility with other formulation components.
Cost Optimization: How to Balance Price and Performance of Additives in Industrial Applications
The price of an additive is often a decisive factor, but when selecting, it is necessary to consider the total formulation costs, not just the unit price per kilogram. For example, a more expensive additive with higher efficiency may reduce the required dosage, leading to material savings and lower storage and logistics costs. In coatings, it is worthwhile to compare the costs of additives with their impact on the service life of the coating – for instance, anticorrosive additives can extend surface protection by tens of percent, thereby reducing the frequency of repairs and maintenance.
In industrial applications where coatings or paints are produced in large volumes, it is crucial to test additives under real-world conditions. Laboratory tests often do not reveal all aspects of an additive's behavior in mass production, such as its stability during long-term storage or interactions with other components. Suppliers should offer samples for verification in specific formulations and provide technical support for optimizing dosage. In some cases, comparable performance can be achieved with a cheaper additive if the overall formulation is adjusted, for example, by changing the ratio of binders or fillers.
Trends and Innovations in Coatings and Printing Inks Additives
The development of additives for coatings and printing inks is moving toward multifunctional products that combine several properties in one. For example, modern additives for improving spreadability can simultaneously reduce foaming and enhance scratch resistance. This trend allows for simplified formulations and a reduced number of required components, leading to savings in logistics and production. Another significant direction is the development of additives based on renewable raw materials, such as vegetable oils or cellulose derivatives, which reduce dependence on fossil resources.
In the field of printing inks, additives for digital printing are increasingly being used to improve adhesion to various substrates or enhance resistance to abrasion and chemicals. For water-based coatings, there is growing demand for additives that improve moisture and mold resistance without using isothiazolinone-based biocides, which are under increasing regulatory pressure. Innovations are also focusing on additives for special applications, such as coatings with antibacterial properties or inks for 3D printing, where color accuracy and stability are key.
Need Help Choosing Additives?
GCG Group provides detailed technical data sheets and safety documentation (SDS) for every chemical raw material, including recommendations for specific applications. Our experts will be happy to advise you on selecting additives and optimizing formulations for your specific needs. Contact us – or browse our catalog of over 1,300 products right away.
