Automotive Leather - Determination of loose grain effect
Material
Industry
Our test laboratory performs accredited testing according to VDA 230-205. The standard describes a standardized method for determining the so-called "Loose grain effect" in leather for automotive interior applications. The purpose of the test is to evaluate the bond strength between the grain layer and the fibrous structure, as well as the tendency of leather to develop visible wrinkling, waviness, or bulging on the grain side under mechanical stress.
Test Procedure and Evaluation
In the test procedure, the leather is bent concavely over a half-cylinder (“Halpi”) with a defined radius. The resulting wrinkle formation on the grain side is photographically compared with reference samples and evaluated using a five-grade rating scale. This standardized procedure enables reproducible assessment of the extent of the loose grain effect.
The test is included in numerous material specifications and, in modified form, is also applied to artificial leather, for example in DBL 1200, DBL 5310, BMW TL 9879076.6 (for wrinkle formation of trilaminates in artificial leather), BMW GS 93039 (adapted for artificial leather), and BMW QV 11739234 (adapted).