ASTM D6441-05(2024) pdf - Standard Test Methods For Measuring The Hiding Power Of Powder Coatings

ASTM D6441-05(2024) pdf - Standard Test Methods For Measuring The Hiding Power Of Powder Coatings.
 These test methods determine and report the hiding power of a powder coating with respect to two parameters:
1.1.1 Test Method A—Contrast Ratio at a given film thickness
1.1.2 Test Method B—Film thickness at 0.98 (98 %) contrast ratio.
1.2 These test methods cover the determination of the hiding power of powder coatings applied by electrostatic spraying.
1.3 These test methods determine hiding power by means of reflectometric and thickness gauge measurements. They are limited to coatings having a minimum CIE-Y reflectance of 15 %.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
NOTE 1: The measured parameters follow powder coating industry practice by measuring hiding power in relation to film thickness, rather than the “Spreading Rate” function employed in Test Methods D344 and D2805 and other hiding power test methods.
NOTE 2: Hiding power is photometrically defined as the spreading rate at 0.98 contrast ratio. See definitions of spreading rate and hiding power in Terminology D16, D2805, and the Paint and Coatings Testing Manual.