FILK clarifies which forces act during shrinkage of leather?
It is not new that leather can shrink under changing climatic conditions such as temperature and humidity. That is why the examination of the shrinkage of leather is part of routine tests for numerous applications such as furniture, automotive interiors or shoes. The test takes place on unprocessed or unfixed leathers. However, the forces actual acting within the leather material are not recorded.
However, despite acceptable area shrinkage values, cases occur where leather shrinkage is accompanied by a destructive force, especially when leather is firmly bonded to a stiff component, as for example in the case of leather instrument panels in vehicles by bonding. The shrinking force can destroy an entire component and therefor is a relevant parameter for the suitability of leather for certain application.
Scientists at our institute had dedicated themselves to this phenomenon in a research project. A method was developed to determine the effective shrinkage force under changing climatic conditions. Many other parameters were examined for the interpretation of the measurement results. It was found that the two parameters area shrinkage and shrinkage force correlate with each other, but provide fundamentally different information about the material behaviour. The project results for shrinkage force measurement met with particular interest in the automotive industry, which is why the measurement methodology developed was included in the test specification PPV 5002 of the Stuttgart-based sports car manufacturer Porsche. The testing of PPV 5002 is offered as a testing service in our accredited testing laboratory.