Life cycle assessment of UV-Curable bio-based wood flooring coatings

An important recent trend in the paints and coatings industry has been the use of bio-based alternatives to fossil-based building blocks in many applications. This trend is being driven in part by cleaner production and sustainability goals. As bio-based ingredients have been widely shown to present environmental trade-offs along their life cycle, new formulations should ideally be assessed for environmental preference before entering into full-scale production. In this paper, a bio-renewable content (BRC) formulation for wood flooring coating is analyzed using a life cycle assessment (LCA) framework and quantitatively compared to a conventional petrochemical formulation of similar performance across a range of impact categories. This BRC formulation has 50% bio-based ingredients and zero-to-low VOC emissions and was developed by PPG Industries, Inc. The scope of the analysis is cradle-to-gate and includes biomass cultivation and crude oil extraction and refining for renewable and non-renewable chemical inputs, formulation, transport, and application of 1 m2 of each coating, followed by UV-curing. Comparative results show more than 30% reduction in six out of ten impact categories, using the USEPA TRACI 2.1 impact assessment method, with smog formation, acidification, eutrophication and respiratory effects showing increases in environmental impacts, largely due to burdens from bio-based components. Bisphenol A–epichlorohydrin resin and corn-derived itaconic acid are the most impactful chemicals in the composition of conventional and bio-renewable wood flooring coatings, respectively. Energy use from UV-curing does not appreciably contribute to impacts. The contribution of various building blocks to environmental impacts of both coatings are presented in detail, potentially guiding further formulation research and development. Modifying the BRC formulation to use corn stover instead of corn grain for synthesis of sugar-derived chemicals would improve the environmental profile of the BRC formulation, leading to reductions in all impact categories. The results underscore that meeting targets for bio-based content can have multiple secondary benefits to the environment and human health, but these depend on the particular biofeedstock and conversion processes as well as on the petrochemical components that are being replaced.