The Waterborne Symposium 2025

Abstract
"When considering flexible coatings, polyurethane often comes to mind. Polyurethane's flexibility is derived from its unique structure, featuring a combination of hard and soft segments, as well as hydrogen bonding within the hard segment. While polyurethane possesses diverse chemical structures and finds applications in various coatings, 2K polyurethane commonly grapples with several limitations, including the handling of often toxic isocyanates, sensitivity to moisture, yielding soft coatings, moderate curing speed, and constraints on coating thickness. Additionally, 2K polyurethane often necessitates the use of solvents to reduce viscosity for ease of application, resulting in high volatile organic compounds (VOC) emissions.

Epoxy systems are not typically associated with flexibility, as they are primarily recognized for their excellent mechanical properties, chemical resistance, and adhesion to substrates. Epoxy coatings have found widespread use in applications aimed at protecting substrates, enhancing resistance to various chemicals, and extending the service life of materials and assets. Compared to 2K polyurethane, epoxy presents advantages in terms of ease of handling, lack of moisture sensitivity, and the ability to formulate low VOC and low emission solutions. Furthermore, epoxy can be rendered flexible by incorporating a substantial amount of long-chain not environmentally and not user-friendly phenolic plasticizers. The need for fast return to service is a driving force in the coatings industry, often leading to the use of accelerators that, while speeding up curing, can compromise flexibility.

This paper introduces a novel EHS friendly flexible epoxy technology designed to bridge the performance gaps in current flexible epoxy systems using sustainable bio-based raw material. It yields coatings with rapid curing capabilities while maintaining high flexibility, even at low temperatures. These coatings exhibit high hardness, excellent substrate adhesion, substantial tensile and tear strength, all while maintaining an environmentally and user-friendly product profile. Catering to the demand for rapid return to service with minimal emissions and extended working time. The paper will also delve into key performance attributes and provide comparisons with 2K polyurethane and conventional epoxy systems.
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Co-Authors: Franklin Leal, and Dan Weinmann

Abstract

Epoxy resins have been used for decades in applications demanding excellent adhesion and corrosion resistance, but historically have not been suitable for coatings where ultraviolet (UV) resistance is needed. A direct-to-metal coating, comprised of a novel modified cycloaliphatic epoxy resin combined with a lower yellowing amine curing agent, was designed to deliver superior performance in corrosion resistance and adhesion. Additionally, this epoxy resin system offers improved gloss retention and color stability compared to standard epoxy coatings. Both the resin and curing agent are optimized to minimize dry time while maximizing hardness development. The relationship between epoxy-amine stoichiometry and coating performance was evaluated to further improve the system. Comparative testing with a commercially available epoxy-polyamide DTM coating showed that the novel epoxy system performs well against the competitive material while significantly improving the UV resistance, as determined by gloss and color retention.
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Abstract

"2K coatings are being heralded as an innovative means to increase the move towards 100% solids materials and reduce the need for thermal curing, thus reducing the energy required for the coating process. While the benefits are indisputable, there are issues associated with these technologies that can make them difficult to process in the manufacturing environment. All of these must be dealt with as part of the application process and, if not properly handled, can result in production delays that reduce throughput, reduce quality, and increase costs. Obviously, this runs counter to the objectives of these advanced technologies.
In this presentation we will:
 define induction time and pot life and the relationship between them.
 discuss the implications these pose to the modern manufacturing process.
 identify novel methods to leverage these properties, turning them from adversaries to allies in the application process.
 identify opportunities to minimize waste, reduce rework, increase throughput, and improve the quality of the coating process."

Bio: Brian Vest, Linda Adamson, Celine Burel

Abstract
"Perfluoro and Polyfluorinated-Alkyl Substances (PFAS) have been extensively utilized across various industries due to their exceptional ability to resist heat, oil, grease, and water. Among these PFAS chemicals, Fluorocarbon Surfactants (FCS) have been particularly effective in waterborne coatings to enhance early ""hot block"" resistance. However, increasing regulatory pressures and risk management considerations are pushing formulators to phase out these substances. This shift necessitates a careful balance between maintaining performance and adopting more sustainable alternatives.

Our study focuses on the development and application of novel phosphate ester wetting agents that offer improved early hot block resistance without the environmental drawbacks associated with fluorocarbon chemistry. These innovative additives are APE-free and have very low or zero VOC content, contributing to better colloidal stability. This stability enhances the wetting, dispersing, and compatibility properties of the final water-based coating. Our data will demonstrate the overall performance of the paint and explore the structure/property relationships that contribute to enhanced anti-blocking performance."

Abstract

Dirt pick-up resistance (DPUR) is a critical property in surface coatings, particularly for outdoor applications. Additives play a crucial role in enhancing DPUR by improving both the visual appearance and durability of coated surfaces. Silicone-based compounds, hydrophobic agents, and nanoparticles have been shown to reduce surface energy, thereby minimizing the adhesion of dirt particles and dirt slurries. In addition, certain polymeric and film-forming additives can improve surface smoothness and reduce porosity, further preventing dirt accumulation. The incorporation of photocatalytic additives has also been explored, leveraging their self-cleaning properties under sunlight exposure. This paper reviews the different types of additives used to enhance DPUR, their mechanisms of action, and their effectiveness with various methods. The optimization of additive in the formulations is key to achieving a balance between surface protection, durability, and environmental considerations, making them necessary in modern surface coating technologies.

Co-Authors:
Tom-Seung Cheung, and Yanjun Luo

Abstract
PFAS compounds provide surface tension (ST) reduction, coefficient of friction (COF) reduction, hydrophobicity, oleophobicity and chemical stability.  These fundamental properties result in applications such as stain resistance, block resistance, oil resistance, lubricity, release, AFFF and many others.  
Siltech have presented previously on replacing PFAS components with organomodified silicones which provide similar and satisfactory performance on ST, COF and hydrophobicity. The difficult challenge is oleophobicity. We have had some success in this category and will report this here. We will emphasize some UV cured acrylate structures which are giving strong performance in this critical category.

Abstract

Stability under low shear storage and shipment conditions can be critical to the stability of waterborne coatings and dispersions against sedimentation and syneresis. Judicious selection of a fit-for-purpose low shear thickener plays a crucial role in preventing sedimentation, especially in cases where dense pigments are incorporated into waterborne formulations. During the application process, traditional thickeners enhance sag resistance and influence leveling to facilitate robust film build. More importantly for longer-term storage, low shear thickeners can prevent syneresis in colorant-tinted coating systems. This presentation introduces an innovative rheology modifier technology based on a novel zirconium complex that eliminates sedimentation and syneresis under extremely low shear conditions associated with coating storage and transport. This technology offers the user-friendly option of post-addition under moderate mixing conditions, in contrast to other rheology modifiers that require neutralization and high-speed mixing processes. This presentation shows results illustrating the valuable outcomes achievable through the utilization of this unique low shear thickener platform.

Abstract

"Regulatory activity in both the EU and USA is targeting a large group of chemicals known as PFAS (per- and polyfluoroalkyl substances). As a result, formulators in many industries are working to replace additive powders based on PTFE and PTFE hybrids with alternative materials that provide the same level of performance.
This presentation will detail a unique nanocomposite approach to eliminate PTFE in surface additives by replacing PTFE with hard, inert, durable materials such as aluminum oxide and ceramics. Data will be presented to show that this portfolio of over 8 additives provides equal or (in most examples) improved surface durability (lubricity, scratch & abrasion resistance) without the use of PTFE."

Abstract

The increasing demand for sustainable solutions in coatings has prompted the development of innovative renewable defoamer technologies. This presentation explores the formulation of a cutting-edge defoamer derived from bio-based resources, focusing on its physical and chemical attributes that optimize defoaming effectiveness without compromise in wetting. The new defoamer achieves significant regulatory compliance and boasts a renewable bio-based content exceeding 75% while being mineral oil- and siloxane-free. This development redefines performance standards for renewable defoamers.

Join us for our fourth annual lightning round style Graduate student poster competition Sponsored by Evonik. Each student will be given five minutes to present his/her poster to the judges and audience and answer questions about their work.

Moderated by Tristan Clemons

Our students will also be available during all the coffee breaks.