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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