Leather - Test for adhesion of finish
Material
Industry
Our test laboratory performs testing according to DIN EN ISO 11644 in an accredited procedure for the determination of the adhesion of finishes to leather. The standard describes a standardized method for evaluating the bond between the leather surface and the finish layer, as well as between individual layers of a finishing system. The test is used to assess the quality, durability, and suitability for use of finished leathers. It is particularly relevant for pigmented and coated leathers with continuous finish layers, such as those used in the automotive, furniture, footwear, and apparel industries.
The test is particularly suitable for the evaluation of leather surfaces with regard to:
adhesion strength of finishes and coating systems
bond strength of multilayer finishing systems
resistance to mechanical stress
quality and durability of pigmented leather surfaces
process and production control in leather finishing
in our testing lab also failure analysis in cases of delamination, peeling, or flaking of finish layers, including support in complaint investigations
The standard is intended for finished smooth leathers with continuous coatings. However, the method is not suitable for leathers without a continuous finish layer, such as nubuck, suede, aniline, pull-up, or perforated leathers.
Procedure of the Adhesion Test
In this test, a leather specimen with its finished surface is bonded to a rigid adhesion plate. The free leather strip is then peeled from the plate in a tensile testing machine under defined conditions at an angle of approximately 90°. During the test, the finish layer remains fully or partially on the plate. The force required for separation is continuously measured and evaluated as the adhesion strength of the finish.
Among other things, the standard specifies:
defined requirements for adhesives and adhesion plates,
a constant test speed of 100 mm/min, and
the recording of a force-displacement diagram for evaluation of the peeling behavior.
In addition, tests can be performed on pretreated or conditioned specimens, for example after exposure to humidity, heat, or aging, in order to evaluate the behavior of the finish under practical service conditions. The investigation is frequently used in combination with other leather tests such as abrasion, scratch, flex, hydrolysis, or climate cycling tests.