Cork micro particles used to increase the strength of joints between automotive components

Structural adhesives are a type of glue that guarantee a continuous, simple, economic and resistant fixation, and are used in several industries. In the automotive sector, these have been increasingly applied, due to the increasing demand for multi-material solutions, with improved mechanical properties, lighter, more efficient and cheaper.

However, although they are replacing traditional techniques such as welding, riveting or bolting, they may prematurely fail because of the tension concentration at the ends of the areas bonded together, or, in accordance with technical terminology, in the adhesive joints.

In order to solve this problem, INEGI has developed an innovative technique that uses magnetized cork micro particles to improve tension distribution and create stronger bonds.

"There are several methods to reduce the concentration of tension, one of which is the use of functionally graduated adhesives", explains Ana Queirós, responsible for the project at INEGI. "In this project we propose the use of micro particles in an optimized configuration to reduce tension concentration and improve performance."

The innovation lies in the non-uniform distribution of the reinforcing micro particles. The technique results in "a greater resistance of the adhesive joint, which in turn enables the reduction of weight, a key factor in the automotive sector, as well as the reduction of costs", explains the researcher.

This process is being developed as part of a project coordinated by INEGI, in collaboration with the Universidade Carlos III de Madrid and the Universidade Pontifícia Comillas, which resulted in a spanish patent granted in 2017, regarding the production process of cork micro particles.

The use of this material, besides enabling better mechanical properties in the adhesives, also gives a new use to cork dust, a product underutilized by the cork industry, whose elimination currently implies an extra energy consumption and often results in accidents.

The project now contemplates the development of the adhesive and the optimization of the production process, as well as its experimental validation.

Soon it will advance to a second phase, dedicated to the development of a tool that promotes the graduation of the adhesive joint, with the support of the Ricerche FIAT Center and the company DowDupont.