Mould T12G Metopac™ panel sheets

The most important applications are

• ASTM Method D 6441 - Measuring the Hiding Power of Powder Coatings - A wedge-shaped film is applied to a T12G or T12M plate. Dots with a certain film thickness are localised over the black and white areas, the reflectance is measured and the average contrast ratio at this film thickness is calculated. Alternatively, several pairs of black/white dots of the same thickness at different layer thicknesses of the wedge are determined, measured and the calculated contrast ratio is plotted graphically at the corresponding layer thickness in order to find the layer thickness at a contrast ratio of 0.98. In this method, the reflectance is measured with a small diameter aperture (e.g. 4 mm) and the coating thickness is measured with an electronic coating thickness gauge.
• Powder Coatings Institute Method - With this method, the film thickness is determined directly on a T12G plate with a contrast ratio of 0.98. Alternatively, the contrast ratio is determined at a specific coating thickness. Reflectance and film thickness are measured as in ASTM D 6441.
• ASTM Method D 2805 - Hiding Power of Paints by Reflectometry - The film is applied evenly to a plate. The film weight and the reflectance R0 are determined on the black surface, and the reflectance R∞ of the coating is determined using the black and white surfaces. The gravimetric spreading rate at a contrast ratio of 0.98 is then calculated using the Kubelka-Munk equations. The conversion to the volumetric spreading rate or to the coating thickness is easy to perform.

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