Test Methods For Scrub Resistance

Paints often become soiled, especially near doorways, windows, and in work and play areas. These test methods cover the determination of the relative resistance of different paints to erosion when repeatedly scrubbed during the life of the paint. These test methods cover a procedure for determining the resistance of wall paints to erosion caused by scrubbing, referred to herein after as “scrub resistance.”Two test methods are covered as follows: Test Method A—Cycles-to-failure obtained on test paint. Test Method B—Ratio expressed as a percentage of cycles-to-failure obtained on the test paint to that obtained on a concurrent run with a known reference paint.   Test Method D4213 is a similar scrub resistance test using a weight-loss technique and reporting volumetric film erosion rates.Test Method A measures scrub resistance by the traditional cycles-to-failure concept. Poor correlation in scrub testing can be attributable to among other things variations in the stiffness of the brush bristles, condition of washability tester, application and drying conditions. In an attempt to improve reproducibility, Test Method B has been developed.