Development of Low-Color Alkyd Resins with High Content of Biobased Succinic Acid
Although alkyd resins are considered to be a biobased, sustainable system due to the use of glycerol and fatty acids, there is increasing pressure to further improve the biobased, sustainable footprint of these resins. One significant opportunity to improve the biobased carbon content of alkyd formulations is by replacement of aromatic diacids and anhydrides with organic acids from renewable, non-petrochemical feedstocks. Ecoat and BioAmber have initiated a study on the partial replacement of petro-based phthalic anhydride (PA) by BioAmber’s biobased succinic acid in pentaerythritol alkyd resins (Penta resins). The preliminary findings suggest biobased SA can replace between 20-35% of the PA, producing a polyester alkyd resin with improved b* color values while maintaining adequate drying time and Persoz hardness values when formulated into matt-based alkyd paints. This study builds further on the commercial introduction of Ecoat’s Secoia® 1404 biobased alkyd binder emulsion.
Biobased succinic acid (Bio-SA) has emerged as one of the most competitive of the new biobased chemicals. As a platform chemical, Bio-SA provides researchers and product developers a valuable and sustainable chemical building block to enable innovative development of differentiated high-performance materials. Bio-SA and its derivatives, such as polyester polyols, have demonstrated performance advantages in polyurethanes, with several recent articles published on this topic.1,2 Given the similarity in the chemistries, it was reasonable to extend the technology from polyesters for polyurethane to polyesters in alkyd-based coatings. Although SA can be produced from petro chemical feedstocks, this process is inherently energy intensive and requires C4 petrochemical raw materials, which are under increased price pressures due to decreasing supplies and refining capacity. On the other hand, BioAmber has produced Bio-SA on a commercial scale since 2010, and is currently building the world’s largest biobased succinic acid plant in Sarnia, Ontario Canada.3 The fermentation of glucose to bio-succinic acid is a process that has a greatly enhanced life cycle analysis (LCA), improved greenhouse gas (GHG) reduction and energy utilization. The fermentation of sugar feedstocks results in excellent utilization of the sugar-based carbon and sequestration of CO2 to produce Bio-SA in high yield and purity (Figure 1).