The specular gloss measurement of the mirrored aluminum plate was measured using a gloss meter to determine the specular gloss of the coating at geometric angles of 20°, 60° and 85°. The 60° method is suitable for all gloss ranges, but for very glossy or near-glossy coatings, the 20° or 85° rule is more suitable. The 20° method improves the discrimination ability for high-gloss coatings. It is suitable for coatings with a 60° gloss of more than 70 units. The 85° method can improve the discrimination ability for low-gloss coatings. It is suitable for 60° gloss of less than 30 units. Coating.
This test method is not suitable for determining the gloss of metal-containing pigment coatings. The gloss meter used in this test consisted of a light source portion and a receiving portion. The light source directs a parallel or slightly concentrated beam of light through the lens toward the surface of the coating. The reflected light is concentrated by the receiving portion of the lens, absorbed by the photocell through the field diaphragm, and then measured by the receiver measuring instrument. The value measured by the receiver meter is proportional to the luminous flux through the field of view of the receiver.
The gloss is measured by the test method, and the sample used must be a coating on a flat surface. If the substrate is slightly bent or partially uneven, the measurement result may be seriously affected. In addition, the film thickness of the sample to be used must meet the specified requirements. The level of the surface to be inspected should be the same as that of the product. The surface must be clean and cannot be touched by hand because these factors will affect the measurement results.
In addition to the above specified 20°, 60° and 85° geometric angles, some instruments also use geometric angles of 45° and 75° to determine the specular gloss of the outer surface of the product. When measuring specular gloss, the appropriate geometric angle should be chosen for measurement.