This part of ISO 6272 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 term “impact resistance” is included in the title of this part of ISO 6272, but one 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 the minimum mass and/or drop height for which the coating cracks or peels from its substrate by gradually increasing the drop height and/or the mass.