Influence of biobased polyol type on the properties of polyurethane hotmelt adhesives for footwear joints

Abstract

Polyurethanes, one of the most used polymers worldwide, are strongly dependent of non-renewable fossil resources. Thus, boosting the production of new polyurethanes based on more sustainable raw materials is crucial to move towards the footwear industry decarbonisation. The aim of this study is to synthesise and characterise reactive hotmelt polyurethanes from biomass and CO2-based polyols as bioadhesives for the footwear industry. The influence of biobased polyols on the polyurethane structure, and therefore, on their final properties was analysed by different experimental techniques such us Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Melting viscosity, Softening temperature and T-peel strength test, in order to assess their viability for the upper to sole bonding process. The results obtained indicated that the incorporation of different amounts of the biobased polyols produces changes in the structure and final performance of the polyurethanes. Therefore, adhesion test carried out by the T-peel test 72 h after the upper -to- sole bonding of the sustainable adhesives show high final adhesion values. These sustainable raw materials provide polyurethane adhesives with additional beneficial non-toxicity and sustainable characteristics, without harming their properties during their useful life.

Polyurethane Adhesives with Chemically Debondable Properties via Diels–Alder Bonds

“…The experiments were conducted in an inert nitrogen atmosphere (flow rate = 30 mL min −1 ) at a heating rate of 10 °C/min. The optimal conditions for DSC experiments had been optimised by the authors in a previous work [ 37 ].…”

Valorization of Agricultural Rice Straw as a Sustainable Feedstock for Rigid Polyurethane/Polyisocyanurate Foam Production

“…One of the most well-known PU products is rigid PU foam (RPUF), commonly employed in construction and insulation applications due to its exceptional insulating properties and structural integrity. − PU synthesis entails the reaction between hydroxyl (−OH) groups in polyols and –NCO groups in isocyanates, , (Figure ). The polyol types significantly influence the resulting PU properties. ,− Traditionally, polyols used in PU production are primarily derived from petroleum feedstocks. However, industrial-scale petroleum-based PU production is associated with substantial adverse environmental impacts, contributing to global environmental hazards. , This presents a pressing need to explore alternative and sustainable sources of polyols for PU production considering the environmental and economic challenges associated with petroleum-based polyols.…”