Abstract

The deployment of composites for lightweight solutions in the automotive market is still emerging due to the production cost of these components and the limited production capacity of current manufacturing technologies.

The development of more reactive formulations for processes that allow to increase production rates and reduce process times to a few minutes are arousing great interest, such as the HP-RTM (high pressure RTM) and the HP-CRTM (RTM compression).

In the case of RTM resins, ultra-fast (2-5min) and low viscosity curing formulations are sought to optimize the curing and injection cycles to the maximum. The technology based on polyurethane resins (PUR) offers against other alternatives the advantage of having great tenacity and resistance to fatigue which makes it especially attractive for elements subject to impacts or cyclic loads such as suspension elements.

This work, based on simulations, has determined an optimal value of the PUR viscosity for RTM. In addition, a preliminary analysis of the curing kinetics of a commercial PUR resin has been carried out. The results indicate that the resin evaluated is not viable for the process due to its high reactivity at the beginning of curing, so that work will continue on the search for more latent PUR solutions for RTM.

Abstract

The industry decarbonization has become in a fundamental challenge for the industries such as automotive or wind power. In this way, the structural components lightening is one of the principal issues for material manufacturers. For this objective, the composites are a competitive alternative, due to their unique relation between their strength and weight. Among the different structural composite part fabrication processes, liquid composite moulding (LCM) is one of the most interesting, due to its efficiency in terms of costs, time and energy consumption.

In this sense, resins with fast cure and low viscosity are gaining attention, among them polyurethanes are of particular interest.

This family of polymers is characterized by its great versatility, among them high-performance thermosetting polyurethanes (PUR). The advantages offered by PUR-based technology are great fatigue resistance, low viscosity and fast cure. However, the commonly used PUR’s for structural applications have some environmentally drawbacks, such as their components petrochemical origin and their low recyclability. For this reason, the aim of this work was the development of a more sustainable PUR formulation with the required mechanical properties for structural applications and suitable processability for LCM processes. Because of that, this work has focused on the analysis, synthesis and characterization of new PUR formulations and also the manufacturing process simulation and optimization.