Water-borne coatings: “Controlled conditions are preferred but not compulsory”
Dominique Vandenberghe, technical service manager epoxy coatings, fibers & textiles, at Westlake gives insights into trends and challenges in water-borne coatings.
Where is research and development in water-based coatings currently focusing on?
Dominique Vandenberghe: A key driver within Westlake Epoxy R&D is to develop new products with more sustainable attributes and for safer use. For coating applications, an important focus area remains the reduction of VOC emissions to improve air quality, targeting to entirely remove those emissions. This is what we are covering with our “Aquareous” epoxy range.
Besides, we are always striving to develop water-borne epoxy systems with enhanced performances and functionalities, that enable coating manufacturers to produce paints with a longer service life, faster return to service and higher protection level. This will ultimately result in improved efficiency and reduction in material and energy demands.
In the current commercial environment, another important element is cost reduction and improved reliability of supply. Consequently, there is a stronger focus on local production, implementation of alternative production sites and second supply options.
What would you say are the final hurdles in the switch from solvent-based systems to water-based alternatives?
Vandenberghe: Water-borne epoxy performance has advanced significantly over the past forty years, and they can certainly provide equal or even better performances than traditional solvent-borne systems. There are indeed still some remaining challenges when transitioning from solvent-borne to wate-rborne coatings. These challenges fall into two primary categories: formulation development and application properties.
In formulation development, the main challenges are robustness, cost, user-friendliness and ease of formulation. Formulating water-borne paints is often more complex and a good formulation knowledge is critical to develop stable paints that can be easily applied and that show superior film performance. To this end, Westlake Epoxy is developing products, such as our new enabling curing agent, that support the reduction of the number of components in the final paint and thus simplify formulation.
Regarding application properties, water-borne epoxy coatings are challenged when uncontrolled harsh conditions are present. This is the case when the end-use requires application at lower temperatures (<10°C) and higher relative humidity (>80% r.h.). Under these conditions, the reactivity of the two-part epoxy/amine system slows down, and the high relative humidity makes it more difficult for the water to evaporate from the coatings.
Although those challenges are recognised, the advantages that water-borne systems bring, such as low VOC levels, improved worker safety and high performance, often compensate these constraints. Also, water-borne epoxy systems are ideal for application in confined spaces, shop primers, etc. This demonstrates that controlled conditions are preferred but not compulsory.
How would you describe the market for water-borne coatings raw materials at the moment?
Vandenberghe: The demand for water-borne systems in medium and long term keeps increasing. This demand trend is clearly linked to the ongoing transition from solvent-borne systems, mainly in the transportation and general industry coatings segments.
At the same time, the raw material and logistical constraints combined with price volatility and higher energy costs had a significant impact on water-borne epoxy supply in 2021 and 2022. Nevertheless, this situation is not limited to epoxies. Depending on the recovery of global economy, we are expecting an improvement by the end of 2023 at the earliest, most likely during the first half of 2024.
You will be speaking at the EC Conference Biobased & Waterbased Coatings in November what can participants expect from your talk?
Vandenberghe: We will show our newly developed water-borne epoxy resins and amine curing agents, that can be effectively combined to tailor water-borne coatings to specific application requirements and meet the highest standards for corrosion and mechanical protection, while maintaining ease of formulation, meeting stringent VOC legislation, and increasing workers safety.
Event tip
Meet Dominique Vandenberghe at the EC Conference Bio-based & Waterbased in Berlin. The event on November 22 and 23 offers a hand-picked programme with two joint keynotes, 18 presentations by top-notch speakers in two parallel sessions on two of the hottest topics in coatings.
