Semnificație și scop
5.1 The contrast at the specified film thickness is a useful hiding power parameter for production control and procurement specifications.

5.2 The greater the hiding power, the less paint is required per unit area to obtain sufficient hiding power. Prin urmare, knowledge of hiding power is important for coating costs and comparing coating values.

ASTM D 6441-1999 Metodă de testare standard pentru determinarea puterii de acoperire a acoperirilor cu pulbere

Scopul
1.1 These test methods determine and report the hiding power of powder coatings based on two parameters:

1.1.1 Metoda de testare A — Contrast at a given film thickness

1.1.2 Metoda de testare B — Film thickness at 0.98 (98%) contrast.

Notă 1: The measurement parameters follow powder coating industry practice by measuring the hiding power with respect to film thickness, rather than the “spread rate” function used in test methods D344 and D2805 and other hiding power test methods.

Notă 2: Hiding power is defined in luminosity as spread rate at 0.98 contrast. Please refer to terms D16, D2805 and the definitions of diffusivity and hiding power in the Paints and Coatings Testing Manual.

Notă 3: A contrast ratio of 0.98 is generally accepted by the paint industry as “full” coverage for reflective coverage measurements. But visually and photologically, it is still slightly incomplete.

ASTM D 6441-1999 Metodă de testare standard pentru determinarea puterii de acoperire a acoperirilor cu pulbere

1.2 These test methods include determination of the hiding power of electrostatic sprayed powder coatings.

1.3 These test methods determine the hiding power by measuring with reflectometer and thickness gauge. They are restricted to coatings with a minimum CIE-Y reflectivity of 15%.

1.4 Valorile exprimate în unități SI ar trebui considerate standard. Valorile date în paranteze sunt doar pentru referință.

1.5 Acest standard nu este destinat să abordeze toate problemele de siguranță, dacă există, asociat cu utilizarea acestuia. It is the responsibility of users of this standard to establish appropriate safety and health practices and to pre-determine the applicability of regulatory restrictions prior to use.