“What are high solids coatings?”
A common question in the coating world, high solids coatings do have notable benefits over their counterparts. Here’s what you need to know.
High Solids Vs Low Solids
High solids generally refer to a paint that is formulated with a higher resin concentration and lower volatile organic compound (VOC) concentration. High solids coatings are made up of at least 65% solid components that include binders, pigments, and additives. On the other hand, low solids coatings are specifically formulated to contain more solvents. This increased solvent concentration allows for easier application, cheaper manufacturing, and easier storage. However, these solvents evaporate quickly after application causing the coverage area of the coating to be significantly less than that of a high solids coating.
In the diagram above, the low solids formulation contains 50% solvents, resulting in X amount of surface coverage. In the higher solids’ formulation, with 20% solvents, the surface coverage increases by 30%. In a 100% high solids formulation like Ecocoat Kenzo Base, there are no solvents and only 100% pure coating.
Wet Thickness vs Dry Thickness
The difference between the initial application of a coating and the cured coating is referred to as the wet thickness (WT) and dry thickness (DT) of a coating. For 50% solid coatings, since the solvents evaporate after application, the cured coating would require 2 coats to have the same thickness as that of the cured coating for a 100% high solids coating. See the diagram below.
While most low solids coatings rely on solvents for easy application, much research and development have been undertaken to develop 100% solids coatings to allow them to be applied without solvents.
A 100% solids coating also means zero VOCs. The formula is, therefore, more environmentally friendly as less solvent is discharged during the curing process. Solvent-based coatings are considered a major source of harmful VOCs.
Why high solids are not used as much?
High solids coatings are more eco-friendly, durable, cost-effective, and don’t pose much of a threat to human health. However, it is more expensive to manufacture and store, and requires a higher level of technical expertise to apply.