When we have particles that need to be dispersed into a liquid medium or a continuous phase, it is necessary to have additives that can stabilize the dispersion. Large, agglomerated particles need to be broken down into primary particles through the process of wetting and grinding, after which a dispersant additive prevents re-agglomeration and develops opacity or color strength. Dispersant chemicals are a key ingredient in achieving good particle separation and dispersion in paint coatings.
The two functional parts of a dispersant are an anchor, which provides stronger adsorption to the surface of the pigment, and polymer chains, which are stabilizing. Anchors can be single anchors (monomeric) or multi-anchors (polymeric), the latter providing stronger anchoring. In waterborne dispersants, three potential types of stabilization are electrostatic, soluble steric chains, or both (electro steric).
The amount of dispersant required for a specific application is calculated based on the pigment surface area as a percentage additive on weight of pigment (AOWP). Optimum AOWP should be expected to add some amount of viscosity while achieving a maximum of color strength and minimum of particle size. Too little dispersant additive will not achieve optimum results and too much additive will result in unanchored dispersant in solution that will compete with the solvent and add unwanted viscosity.
Hyperdispersant is a term used to focus on the highest performing polymeric technologies. Optimally designed hyperdispersants can achieve the highest possible pigment loadings at the lowest viscosity, the smallest possible particle size with narrower particle distribution, and provide maximum color strength, highest gloss, and long-term coating stability. And of course, optimal hyperdispersants should have minimal impact on coating performance.
Waterborne hyperdispersants in action
Many ideal applications for waterborne hyperdispersants are situations where we are looking for good performance, but not necessarily the highest performance in every area. Examples of these applications are:
- In-plant colorants for architectural and decorative paintings and coatings
- Construction coloration such as concrete, stucco, and façade paint
- Wood finishes
- Leather and textile coatings
- Rubber latex (natural and synthetic)
- Road marking and striping
Finding the right hyperdispersant to fit a specific purpose will ensure the appropriate cost-in-use and prevent wasted money.
Lubrizol Solsperse W430
Watch our Supplier Spotlight Video from April 2022 featuring Jeff Norris, Lubrizol’s Performance Coatings Group Technical Marketing Manager for Hyperdispersants.
In the video, Jeff compares Lubrizol’s Solsperse W430 to other popular additives. Based on the comparisons, Solsperse W430 is shown to be effective on a broad range of pigments and compatible with many resin types, while also reducing cost-in-use and improving performance of coatings.
Interested in the benefits of Solsperse W430?