Coatings, particularly the high gloss coatings used on automobiles, boats, toys, etc., are subject to a wide variety of conditions (for example, wiping, cleaning, and exposure) that can mar their surface. The ability of these coatings to maintain their appearance is an important product attribute. These test methods provide a way to estimate the ability of high gloss coatings to resist mar damage.

These test methods do not provide fundamental values. However they are suitable for estimating the ability of high gloss coatings to resist mar.

Since the susceptibility of coatings to marring varies widely, the number of cycles that are needed to cause “relevant” mar damage also varies. Usually, 2 to 50 cycles are sufficient.

1.1 Two test methods are included. Test Method A uses a device that contains an abrasive wheel. Test Method B uses a device that contains a wheel that has been fitted with abrasive paper. Either method can be used to evaluate the dry abrasion mar resistance of coatings applied to planar, rigid surfaces. Each test method provides good discrimination between highly mar resistant coatings.

1.2 Mar resistance is assessed by measuring the gloss of abraded and unabraded areas. Mar resistance is directly related to the coating's ability to retain gloss in abraded areas.

Note 1—The mar resistance values obtained by these test methods have no absolute significance. They should only be used to derive relative performance rankings for test panels that have been prepared from the series of coatings that are currently being evaluated. If mar resistance values are quoted between laboratories, it is essential that a common standard be measured and that the values be compared to that standard. Even then, the values should be used with caution.

1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.