The market for UV coatings continues to experience substantial growth, driven by increased environmental awareness and improvements in the coatings themselves with new component technologies continuously being introduced.
The environmental friendliness of UV comes from the fact that the coatings are 100-percent curable formulations. That means there is no drying process, which in turn means no solvent evaporation. UV formulations contain reactive monomers and photoinitiators that cure with exposure to UV light. This has led to UV replacing many solvent-based applications because it reduces volatile organic compounds (VOCs) released in the drying process.
Traditional solvent-based coatings give off organic materials into the atmosphere (VOCs), which can be detrimental to the health of the people applying the coatings as well as being bad for the environment more broadly. Water-based coatings help reduce VOCs, but they often require a good deal of energy to dry.
The Greener Alternative
From an environmental standpoint, UV coatings are often preferred since they do not emit VOCs and need only a low level of energy to dry. With these factors and VOC regulation compliance in mind, formulators are considering solvent changes or moving to UV-curable inks and coatings, which are increasingly seen as a preferred alternative.
The Importance of the Dispersant
Dispersants are a key part of UV coatings. Using the right dispersant can improve UV coatings cost and performance by increasing the stability and lowering the viscosity. It can also improve appearance benefits (color performance), such as enhanced optical density so the same color strength can be achieved at lower pigment content. This delivers cost savings as the same amount of pigment can cover a larger area.
Some dispersants for UV coatings provide enhanced optical properties, including gloss and color strength. They also enable formulators to switch to UV technology by providing stability in the ink or coating when using a variety of reactive monomers and oligomers. The dispersant should enable other components in the formulation to be the best they can, meaning getting the best colors out of the pigment to deliver the strongest final color on the painted/printed surface.
The Millbase
The milling step of pigment dispersing is another area where benefits can be achieved. The combination of higher pigmentation levels in the millbase and improved pigment utilization in the final coating provides valuable cost benefits.
The process of milling is expensive, so the more pigment that can be put into the millbase and the stronger a color it gives, the less millbase is needed per area of surface to cover.
The dispersant physical form impacts its suitability in production. 100% active pastes and extremely viscous liquids are not desirable because they can be difficult for formulators to handle in their plants, which leads to wasted leftovers in the IBC/drums. So some formulators are forced to use hot rooms to melt or lower the viscosity of dispersant products before use.
Lubrizol offers 100% active, lower viscosity products to reduce or remove the need for hot rooms. Overall, Lubrizol has optimized its dispersants so they are easy to pour and flow at room temperature.
Contact us to learn more about our dispersants for UV coatings and how they can increase stability, lower viscosity and improve color performance.
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