5.1 Coatings, particularly the high gloss coatings used on automobiles, boats, toys, etc., are subject of a wide variety of conditions (for example, wiping, cleaning and exposure) during manufacture and service that can mar their surface. The ability of high gloss coatings to maintain their appearance is an important product attribute. This test method provides a way to estimate the ability of high gloss coatings to resist mar damage.
1.1 This test method covers procedures for evaluating the relative mar resistance of a series of high gloss coatings applied to a flat, rigid surface. Wet rub and dry rub abrasion tests are described. To fully characterize a coating's mar resistance, both tests should be run.
Note 1: Dry abrasion mar resistance can also be evaluated by using Test Methods D6037. If a series of very highly mar resistant coatings is being evaluated, Test Methods D6037 will generally provide the better performance discrimination than the dry rub test described here. However, if the equipment described in Test Methods D6037 is not available, the dry rub test described in this test method affords a reasonable alternative. The dry rub test is also useful for evaluating coatings that are not highly mar resistant.
1.2 Mar resistance is assessed by measuring the gloss of the abraded and unabraded areas. Mar resistance is directly related to the coating's ability to retain gloss in abraded areas.
Note 2: The mar resistance values obtained by this test method 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 SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address 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.
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