Articles - Leather Technology Magazine Nº73

Comparative study of test methods for measuring the wear and tear (or wear) resistance of leathers for the automotive industry

Comparative study of test methods for measuring the wear and tear (or wear) resistance of leathers for the automotive industry

Key words: leathers, automotive upholstery, wear and tear resistance, abrasion

ABSTRACT

Introduction
Those persons who buy a leather-upholstered car do it largely because they consider leather to be a noble, distinguished and attractive material. Leather upholstery is a long-lasting item, but its continued use may cause the loss of some of its original qualities.
According to Baumann, the value of a piece of leather is defined by two different kinds of properties: aesthetic values and properties of use.
Among the latter is the resistance to wear and tear (or wear) which allows the determination of the durability of a piece of upholstery through its service life.
A leather-upholstered seat is subject to:
- the daily rubbing or friction of the passengers’ clothes and of the exposed parts of their bodies (hands, hair, etc.);
- repeated flexure accompanied by leather stretching due to the passengers’ movements, the degree of which depends on the passengers’ weight and height.
To assess the wear and tear/wear resistance, automotive companies include different test methods in their specifications for leather. Many of these methods not only are applied soon after leather is finished but also allow, by temperature and/or humidity ageing processes, to predict with some degree of accuracy how the finish will evolve after a certain period of time.
The objective of this work is to compare the methods most commonly used to measure the wear and tear/wear resistance of leather, linking the results with the chemical products utilized in its finishing.

Conclusions
a. The applicability of the different methods employed to measure the resistance to abrasion or to wear and tear depends on the material itself and the type of finish.
b. The size of the samples, their preparation (sewed or not sewed), the test speed, the weight applied and the number of cycles are so variable and diverse that it is not possible to infer the result that would be obtained by one method using a previous result obtained by the other.
c. The Taber test proves to be inadequate to differentiate between wear-resistant and not wear-resistant leather.
d. The most far-reaching test method that best reveals wear resistance, allowing differentiation between wear-resistant and not wear-resistant leather, is the Gakushin method.