Environmental product development: replacement of an epoxy-based coating by a polyester-based coating

The purpose of this study is to document and assess the environmental impacts associated with two competing powder coating solutions using current life cycle assessment (LCA) methods and available data and to check whether there is a conflict between environmental performance and occupational health issues. Data have been gathered for the manufacture and application of the two different powder coatings. The case study is a cradle-to-gate study, using retrospective data. The data were entered into the SimaPro 7.2.4 LCA software and environmental impacts calculated using IPPC 2007, CML-IA and USEtox (TM) classification and characterisation methods. The USEtox methods were used both with and without interim factors, and this distinction was very important for the ranking of the alternatives. The study was performed using the functional unit: Surface treatment of the "foot-cross" of one H05 5300 office chair for 15 years (the lifetime of the chair), where the reference flow was 172 g of powder coating to fulfil this function. Literature about the known health effects associated with chemicals in the two solutions was also consulted in order to assess whether the main concerns driving the desire to replace the epoxy-based powder coating have been addressed and improved through using the polyester-based alternative. The life cycle environmental impacts evaluated show improvements in the potential environmental impacts analysed due to the substitute polyester-based coating. The results for human toxicity and freshwater ecotoxicity potentials are dependent on the inclusion of interim characterisation factors. Literature sources provide evidence of irritation and sensitisation effects associated with epoxy resin, but not for the polyester resin alternative. Substitution of the epoxy-based coating by a polyester-based alternative reduces the occupational health risk for workers coming into contact with the powder coating. The results show that this substitution has also led to reduced potential environmental impacts: global warming, ozone depletion, photochemical oxidant creation, acidification, eutrophication, human toxicity and freshwater ecotoxicity, when the interim factors for some metals and organics are included in the USEtox calculations.