A review of environmental assessments of biobased against petrochemical adhesives

Kurzfassung/Abstract

Bio-based adhesives could be an important addition to dispersion- and solvent-based adhesives due to increasing environmental and health requirements. This could also improve the environmental impact of many composite products. This review aims to examine whether adhesive technologies have already been investigated for their environmental impact and if so, which biomass has been used for which type of adhesive. For this purpose, corresponding studies were conducted and a total of 563 different peer-reviewed articles on adhesives were identified. These articles were then evaluated in a 2-step screening process. Articles in which adhesives themselves, and not just composite products, have already been examined concerning their environmental impact have been analyzed in detail to determine whether adhesive technologies based on renewable raw materials have significantly better environmental performance than conventional reference products. The results provide a comprehensive critical overview of the latest developments in the industry. It becomes clear that the environmental performance of industrial bio-based adhesives is still very controversial and mostly based on assumptions of theoretical and unproven products. The fact that many of the conversion technologies used are still only tested in the laboratory or in the pilot phase and have not yet been implemented to an industrially relevant extent still represents a significant obstacle to the implementation of novel bio-based value chains and leads to additional uncertainties in the decision-making process. However, 70 % of the theoretical adhesives or existing adhesives, which also consist of only a fraction of renewable raw materials, show equally good or better environmental performance. Especially the impact categories global warming and human toxicity indicate a high potential for improvement. In addition, it becomes clear that vegetable oils and starch are particularly suitable as biomass for the green production of adhesives. Although the literature shows a theoretical potential for industrial bio-based adhesives, the market is still immature and is based on a low development of bio-based adhesive options. Against this background, it must be the aim of further scientific work to fill this specific gap by modeling the life cycle of bio-based adhesives from an environmental and economic perspective, which shows the results clearly and transparently and thus also guarantees a good basis for decision-makers.