ISO 6272-1:2011 describes a method for evaluating the resistance of a dry film of paint, varnish or related product to cracking or peeling from a substrate when it is subjected to a deformation caused by a falling weight, with a 20-mm-diameter spherical indenter, dropped under standard conditions.
NOTE The terms impact and impact resistance are used in the title and text of ISO 6272-1, but an important characteristic of the apparatus used is that it should produce rapid deformation rather than a true impact.
The method described can be applied
- either as a pass/fail test, the test being carried out from one drop height and with a specified mass, so as to test compliance with a particular specification;
- or as a classification test, to determine, by gradually increasing the drop height and/or the mass, the minimum mass and/or drop height for which the coating cracks or peels from its substrate.