Metal Content Reduced: New-Generation Water-Based Driers

Alkyd coatings are predominantly used in industrial applications for long-term surface protection. When alkyds dry through air contact alone, the drying process is irregular and requires a very long time. For rapid and effective drying of alkyds, the use of drying agents is therefore essential. Drying agents are organometallic in structure; they consist of octoate or naphthenate compounds of metals such as cobalt, manganese and zinc. Cobalt and lead octoates are the most widely used and most effective surface drying agents in modern industry due to their oxidation catalyst properties. On the other hand, in view of the environmental damage caused by cobalt and lead-containing drying agents and in response to European regulations, their use is being questioned or reduced to minimal levels for environmental reasons. This trend towards restricted use is encouraging the adoption of alkyds emulsified in water. In water-based alkyd systems, reduced solutions of harmful metals in drying agents are also being pursued. For example, ECOS ND® 15 is a water-based drying agent containing only 4% cobalt with polymer-modified properties. At the same application rates, it has the same effect as a cobalt drying agent and is a specialized product. As a result, it has passed REACH toxicity tests with compliance. When the product is compared with a standard product containing 12% cobalt octoate, it has been observed that their drying and hardening processes are equivalent. Beyond low-metal-content drying agent products, different metal content water-based auxiliary drying agents provide additional benefits alongside their main function. Alternative water-based alkyds with less environmental impact and film properties that are as bright and strong as alkyd resin, and consequently water-based drying agents, will play an important role in future products. Cobalt octoate is one of the most widely used drying agents in the Turkish market. Due to its oxidation catalyst properties, it is a powerful surface drying agent. Due to its rapid and active drying properties, it must be used with secondary or auxiliary drying agents. The water-based adaptation of such surface drying agents, Valirex® Co 9 Aqua, is a surface drying agent solution for alkyds emulsified in water. Valirex® Zr 12 Aqua containing zirconium octoate is a very effective auxiliary drying agent. In formulations where Valirex® Co 9 Aqua is used, it is recommended to use it as a secondary drying agent together with Valirex® Ca 4 Aqua. Products such as Valirex® Ca 4 Aqua containing calcium octoate and Valirex® Mix 353 Aqua containing barium octoate are auxiliary drying agent products. Due to their very strong wetting properties, they have the effect of correcting surface defects that occur during drying. They are gloss and film adjusters. When used together with Valirex® Co 9 Aqua, they prevent fillers from bonding with active cobalt, making film drying more effective. Drying agents containing lithium octoate such as Valirex® Mix 265 Aqua and Valirex® Mix 3703 Aqua are alkyd resin hardeners. This hardening process provides the product with protective properties against external weather conditions. Valirex® Mix 265 Aqua and Valirex® Mix 3703 will serve as important building blocks for a product strategy more resistant to external facade conditions. Since the applied films of final products containing effective drying agents such as lithium or cobalt will only trigger oxygen-based drying on the surface portions, the content amounts in the final product and the choice of auxiliary drying agents used together are very important criteria. In the production process, the ratios of the designated drying agents to each other are important. As an alternative to this, pre-mixed products such as Valirex® Mix 353 Aqua, Valirex® Mix 265 Aqua and Valirex® Mix 3703 contribute to the production speed of safe products. Regarding water-based drying agents, particularly in industrial applications for long-term protection purposes, water-emulsified alkyd products and water-based drying agents are gaining ground against the declining trend of non-water-based resins and cobalt-type metals. At this point, water-based and reduced-metal drying agents will become an increasingly important area without causing product performance loss. The Turkish paints and coatings industry currently supplies non-water-based coating and paint products. The drying agent industry is developing its technologies in this field as well. With special metal types and new solvent solutions, drying agent products are being supplied that increase performance, bring additional benefits and even create cost advantages that exceed technical specifications. Among the new generation of non-water-based drying agents, one of the most important products in this regard is Valirex® Ca 10 d60. It is a high-performance auxiliary drying agent with increased metal/acid ratio through new solvent selection. Valirex® Ca 10 d60 has an overbased property. Overbasing, as is known, is the neutralization of the anion with the dominant ratio of metal in the metal/acid chemical ratio in metal salts. In this way, an equilibrium is achieved and the system stores the metal salt at the nano level within itself.

Mustafa Kuru - Key Account Manager, Industry - Kemiropa