DIN EN ISO 12137:2012-01

The standard specifies a method for determining, using a curved (loop-shaped or ring-shaped) stylus, the mar resistance of a single coating of a paint, varnish or related product, or the upper layer of a multicoat system. This test has been found to be useful in comparing the mar resistance of different coatings. It is most useful in providing relative ratings for a series of coated panels exhibiting significant differences in mar resistance. This International Standard does not specify a method using a pointed stylus, two of which are specified in DIN EN ISO 1518-1 and DIN EN ISO 1518-2, respectively. The choice between the three methods will depend on the particular practical problem. The coating or system under test is applied at uniform thickness to flat panels of uniform surface texture. After drying/curing, the mar resistance is determined by pushing the panels beneath a curved (loop-shaped or ring-shaped) stylus. The stylus is mounted so that it presses down on the surface of the test panel at an angle of 45°. The load on the test panel is increased in steps until the coating is marred. The Committee responsible for this standard is NA 002-00-07 AA "Allgemeine Prüfverfahren für Beschichtungsstoffe und Beschichtungen" ("General test methods for coating materials and coatings") at DIN.