How pigment loading impacts coating quality and performance

What happens to a coating once it’s applied, dried and cured?

If you are a consumer, you probably don’t give much thought to that – and why would you? A coating is supposed to have a long application life while protecting the surface and looking as good as the day it was applied. If it’s doing that, the coating is performing well.

As a paint and coatings manufacturer, you know the quality of your product is very important and reflects on your company’s image and reputation in the market. But coatings don’t always protect as they were designed to, or keep their visual appeal. And sometimes, the cause of the problem is added before the coating even leaves the production plant or paint store, in the form of your colorant.

When lower-quality colorants cause problems
Colorants add more than just color to a paint or coating. They can add biocides, resins and other materials that can impact the coating in its final applied state. These components are necessary to stabilize the color in many colorant formulations, but they can also negatively impact the final properties of the applied coating. Higher-quality colorant manufacturers understand the impact of the colorant formulations on the final coating.

As a general rule, the price and the quality of colorants are driven by the amount of pigment in the colorant. A lower-cost colorant most likely has a lower level of pigment and higher levels of fillers, as well as lower-quality stabilizing components in its formulation. This can mean a higher risk of poor quality and performance due to the negative impact of the mill-base components.

Using lower-cost, lower-quality colorants that aren’t highly loaded with pigment can be most problematic in coatings that require high performance and durability. While the price may be less, the coating can fail to adhere properly to surfaces, causing flaking and peeling in a short period of time. Or it might fade quickly or not display the intended level of gloss or reflectivity, which is evident as soon as the coating is exposed to exterior conditions.

Whether the end use is industrial or architectural, the solution for coatings manufacturers is to use colorants that contains the highest level of pigment while maintaining other important characteristics such as rheology. Today’s manufacturers can utilize colorants with higher pigment loading in a wide variety of coatings applications, from household paints to heavy-duty industrial coatings for use on bridges and offshore oilrigs. Here are a few factors to keep in mind when selecting and using highly loaded colorants for your application.

1. Pigment load affects price. When you consider purchasing colorants with higher loading, you can’t simply compare costs based on equal weight or volume. Total colorant cost must be calculated based on equal tinting strength. For example, a colorant with 25 percent pigment may have a price that is half as much as a colorant that is 50 percent pigment. However, you would use half the amount of the colorant loaded with 50 percent pigment, so the as-used costs would be equal.

2. Accuracy and consistency are essential. When adding a colorant to a coating during manufacturing (in plant), it’s critical that the colorants used to tint the bases are consistent from lot to lot. If colorants are not consistent, or the colorants are not added in the ratio specified by the formula, you must adjust the final color with additional colorant, which drives up cost and increases the risk of making an error that makes the batch unusable for sale. Mistints can sometimes be corrected, but doing so adds more cost to the material. Consistency is extremely important for paint bases that are tinted at the point of sale (POS). Technology allows POS dispensing equipment to accurately add highly loaded colorants in doses as small as 1/576th of an ounce or less. Dispensing smaller colorant amounts allows manufacturers to achieve pinpoint coloring accuracy while utilizing highly loaded pigment dispersions, reducing the risk of mistints and the cost of subsequent corrections.

3. Don’t go it alone. Colorant suppliers have years of experience developing colorant technology to meet coatings manufacturers’ requirements for tinting their bases, whether in plant or at the point of sale. The more information about your coloring needs that you can share with your colorant supplier, the easier it will be for your partner to deliver a solution that’s compatible with your coatings requirements.

Chromaflo Technologies is a leading provider of high-quality colorant technologies for the architectural and industrial coatings industries. Contact us at (440) 997-5137 to discuss your colorant requirements.