VW PV 3906 (accredited)

Our test laboratory performs testing according to Volkswagen PV 3906 using accredited procedures. The test specification describes a standardized method for determining the abrasion resistance and rubbing fastness of surfaces using a linear abrasion tester. The method can be applied to painted and coated, self-coloured or flocked surfaces as well as dyed and printed textiles and films.

The test is particularly relevant for surfaces that are exposed to repeated rubbing during use. It enables both the assessment of visible surface changes caused by abrasion and the evaluation of the resistance of the colour to rubbing and staining of other textiles. PV 3906 therefore supports material and surface selection, component development and quality assurance, particularly for automotive applications.

Test procedure according to VW PV 3906

The test is performed using a linear abrasion tester (Crockmeter) or an equivalent device. A defined undyed cotton fabric is used as the rubbing medium and is mounted over the rubbing tool. The number of Crockmeter strokes and the requirements for rubbing fastness are specified in the relevant drawing or standard.
PV 3906 provides for testing with both dry and wet rubbing fabric. For wet testing, the rubbing fabric is wetted under defined conditions and the surface is then subjected to the specified rubbing action. After wet testing, the specimen is cleaned and dried; evaluation is carried out after one hour at room temperature.
Before testing, the specimens are prepared and conditioned accordingly. At least seven days must elapse between production of the specimen, for example by painting or injection moulding, and testing. Before the test, the specimens are conditioned for at least 24 hours under the specified conditions.

Evaluation of abrasion resistance and rubbing fastness

Following the rubbing exposure, the abrasion resistance of the surface is visually assessed under defined lighting and viewing conditions. PV 3906 uses a rating scale from Grade 1 to Grade 4. Grade 1 corresponds to no visible change, while Grade 4 indicates a severe change, such as exposure of the substrate material. For the rubbing fastness of the colour, staining of the rubbing fabric is evaluated. This can be assessed visually using a grey scale or instrumentally using a spectrophotometer. The test therefore enables a differentiated assessment of both the mechanical abrasion behaviour of a surface and possible colour transfer caused by rubbing.

Relation to other standards and test methods

VW PV 3906 is directly related to DIN EN ISO 105-X12, which specifies the determination of colour fastness to rubbing. Specimen preparation and the performance of the rubbing tests are based on this method. DIN EN ISO 105-A03 and DIN EN ISO 105-A04 are additionally referenced for evaluating staining. A further relationship exists with DIN EN ISO 21546, which specifies the determination of the resistance of coatings to scratching using a linear abrasion tester (Crockmeter). The type C rubbing tool defined in this standard is also used for testing according to PV 3906.

Application to automotive surfaces

PV 3906 covers a relatively broad range of non-metallic surfaces. Materials that can be tested include painted and coated plastic surfaces, self-coloured plastic components, flocked surfaces, as well as dyed or printed textiles and films.

The method is therefore particularly suitable for evaluating materials and component surfaces whose visual appearance and colour are expected to be maintained despite repeated contact and rubbing. By combining the assessment of abrasion resistance and rubbing fastness, different aspects of the in-use performance of surfaces can be evaluated under reproducible conditions.