Comparative life cycle assessment of safety shoes toe caps manufacturing processes

Toe caps are fundamental components of safety footwear used to prevent injuries, which can be caused by falling objects. They can be realized by exploiting different materials (metal, composites, and polymers) and manufacturing processes (stamping, injection molding, compression molding, etc.). However, they have always to fulfill the stringent requirements of safety regulations. In addition, in order to guarantee ergonomic use, they must be as light as possible. It was estimated that at least 300 million pairs of safety footwear, with 600 million of toe caps, end up in landfill or are incinerated every year. This huge amount of wastes generates a high environmental impact, mainly attributable to toe caps manufacturing processes. In this context, it is important to develop new solutions aimed at minimizing the environmental impacts of toe caps manufacturing processes. Furthermore, the reuse of carbon fiber prepreg scraps has been recognized as a valid method to produce effective toe caps. In this paper, the life cycle assessment (LCA) methodology was exploited to perform a detailed analysis of the environmental impacts associated with toe caps obtained by reclaiming prepreg scraps. The results, in terms of cumulative energy demand, global warming potential, and ReCiPe endpoints, were compared to those obtained by LCA of toe caps in steel, aluminum alloy, polycarbonate, and glass fiber reinforced composite. The analysis demonstrated that toe caps in steel present the lowest environmental footprint but they are the heaviest ones. The reclaim process for carbon fiber prepreg scraps can be a valid alternative to produce sustainable and lightweight toe caps for safety footwear.