Creating chemistry for a sustainable future

Novel Formaldehyde-Free and Melamine-Free Resin for Stoving Coatings

Typical one-component stoving coatings have concerns with GHS regulations for melamine and formaldehyde both within the SDS classifications of the coating itself and emission concerns once the coating is applied.  We present herein a novel formaldehyde-free and melamine-free thermal crosslinking coating technology for use in typical stoving coating applications, including metal packaging and general industrial.  With our approach, a dual-functional carboxylic-acid and alcohol-based dispersion when coated, under the addition of heat, forms an “acrylic dispersion-modified” polyester with a high level of crosslinking while releasing only water.  No additional crosslinkers or biocide are needed, and the finished coating produces similar hardness and mechanical properties when compared to amino-resin crosslinked systems.  Our studies have shown excellent adhesion to metal (including aluminum) and glass with exceptional over-coatability.

Balancing Open Time and Rain Resistance with Diffusing Wave Spectroscopy and Conventional Application Tests

Sufficient open time for an architectural coating is required for painting efficiency that delivers an aesthetically pleasing outcome. Open time can vary widely for an exterior coating because the wet coat may experience extreme weather conditions from humidity and temperature changes to varying wind speeds. Additionally, the open time of the coating can be influenced by solids, pigment volume concentration, polymer composition, rheology modifiers, additives like humectants, and solvents.

This study is focused on developing new polymers to formulate exterior paints with balanced open time and improved early rain resistance. Early rain resistance and open time are seemingly diametrically opposed properties, and it is difficult to improve early rain resistance without negatively influencing open time. Rain resistance was tested by conventional shower head test method as previously reported. Open time is tested by conventional ASTM D7488 and Gardco Quadracycle drying time.  

Further insight on open time was gained by a novel test method using diffusing wave spectroscopy which provides information on critical steps of the film formation such as water evaporation, skinning, and dry through. Diffusing wave spectroscopy accurately detects minimal changes in open time to understand the influence of polymer structure on open time which is essential for developing new polymers.

In this study, statistical design of experiments identified structural factors that can influence open time and rain resistance. New prototypes were developed with balance of early rain resistance and open time enabled by the novel insight.

Formulating bio-based polyols for low-VOC, solvent-borne protective coatings

Protective coating performance has been dominated by solvent-based chemistries, of particular interest, the use of 2K polyurethanes as topcoats providing resistance properties, weathering resistance, and visual aesthetics. The challenge facing the industry is the continual requirement for lowering VOC contributions from applied systems as well as reducing product carbon footprint. We address this issue in this presentation via formulation of 2K polyurethane coatings with 100% solids, bio-based polyols which offer low viscosity and strong reactivity to afford higher solids and lower VOC formulations than conventional formulations. Demonstration of the ability to formulate solely with these polyols as well as using them as blend partners demonstrates the utility and flexibility to formulate over a broad range of performance requirements. 

Novel Bi-modal High Solid Polymer Dispersions and their Formulation in Architectural Coatings

Over the past few decades, the performance of water-based architectural paint has consistently improved. However, latex polymer dispersions used in water-based coatings are typically limited to 45-50% polymer solids. This is due to the close packing limit of the dispersed polymer particles and a sharp increase in viscosity at solid contents much beyond 50%. Consequently, this restricts the formulation options for water-based coatings, including achievable volume solids, rheology profile, and wet and dry film thickness. Additionally, conventional latex dispersions necessitate the transportation and storage of large quantities of water, and higher solid polymer dispersions could help reduce freight costs and/or enhance storage tank capacities.

Here we present advancements in creating novel bi-modal latex dispersions that allow for over 60% polymer solid content. Furthermore, we explore new formulation possibilities in architectural coatings accessible with bi-modal high solid dispersions to achieve higher film build and maximize hiding performance. At the same time, we balance application feel, flow and leveling, and sag resistance for various application methods, including brush and roller applications.

Novel Acrylic Emulsion for Matte Coatings without Matting Agents

Typically matting agents are used in the coating formulations to develop ultra-low gloss coating surface.  In the present work, we have developed a matte coating surface without matting agents. An advanced acrylic emulsion that can inherently diffuse the incoming incident light rays was successfully developed with a “novel emulsion polymerization process”. The process allowed to develop acrylic emulsion with multimode particle size distribution and polymer chains with gradient Tg, gradient Mw and gradient hydrophobic to hydrophilic polymeric chains.  This unique polymer characteristics created two stage stratification during film forming process namely 1) Emulsion particle size dependent stratification before particle rupture 2) Acrylic polymer chain stratification after particle rupture.  This two-stage stratification effectively diffused the light rays by creating micro-rough coating surface without using any external matting agents.  The cured film exhibited less than 10GU at 60° angle.

Investigating the Link Between Lab Test Results and Real-World Exposure: A Study on Grain Cracking Performance of Architectural Paints

Correlating paint film integrity in the lab with wood grain crack resistance in real world exposure is a challenging task. Previously in 2020, we reported on early correlations between adhesion and film mechanics, that when combined could fit a grain cracking predictive model to outdoor weathering (Nicholas Foley, et al., 2020). In this study, we sought to further challenge our own model by greatly expanding our study to include approximately 80 more paints on various substrates. Our aim was to elucidate potential correlations between paint film mechanical properties and real world exposure performance and test the validity of our early model.

Through our analysis, we have identified several significant factors and developed a mathematical model. While still in its early stages, this model shows promise in providing insights into the performance of paints under real world exterior conditions. Further refinement and validation of this model could have significant implications for the paint industry. Such a model can enhance the durability and quality of wood coatings and accelerate the development timeline.