Improving Coating Performance with Biobased Epoxy Resins Derived from Distilled Tall Oil

By Wumin Yu

Biobased materials are increasingly important in the coatings industry as more companies align their sustainability goals to reduce environmental footprints and develop more eco-friendly products to meet customer needs. However, widespread adoption of biobased materials in coating applications can be challenging due to the lack of available biobased materials that are both cost-effective and performance competitive.

To solve these challenges, we developed a series of cost-competitive bio-based epoxy resins using distilled tall oil (DTO) as the feedstock. DTO, a bio-refinery product derived from crude tall oil, is a byproduct of the pinewood pulping process and is 100% biobased. DTO is a mixture of tall oil fatty acids (TOFA)—mainly oleic acid and linoleic acid—and tall oil rosin acids (rosin)—mainly abietic acid and its isomers.

Figure 1 shows the molecular structures of the main components in DTO. The properties of these novel DTO-based epoxy resins can be tuned by changing the ratio of TOFA to rosin in DTO.

The three DTO-based epoxy resins listed in Table 1 are amber color liquids at room temperature, have a biocontent range of 40% to 50% and an epoxy equivalent weight (EEW) ranging from 500 to 700 g/eq. They are designed for use in applications such as coatings, composites and adhesives, and performance enhancement(s) can be achieved with proper formulation.

This article will demonstrate how these novel DTO-based epoxy resins can help improve miscibility and compatibility, water resistance, adhesion, flexibility, impact resistance, and chemical resistance in 2K epoxy coatings.