Fineness refers to the size or uniformity of dispersion , expressed in microns (μm). The quality of paint fineness can affect the gloss, water permeability and storage stability of paint film. Due to different varieties, the required fineness of primer and topcoat is different.
At present, the most commonly used method for measuring fineness is the scraper Fineness Meter. It is constructed as a polished flat plate made of tool alloy steel. There are grooves on the board, and there are scale marks on the edge of the groove, which are divided into several specifications such as 0-50 microns, 0-100 microns and 0-150 microns; there is also a scraper with both edges polished. When in use, drop the sample into the deepest , so that it can fill the groove with a little excess; use both hands to hold the scraper perpendicular to a flat plate, and pull it from the deep part of the groove to the shallow part at an appropriate speed (Usually takes three seconds), so that the sample fills the groove without leaving any residual paint on the plate, and immediately (generally no more than six seconds) observe the position where the particles in the groove are evenly exposed to the light at an angle of 3 mines. Write down the reading on the scale line, which is the fineness of the test. This method is easy to operate, easy to clean, and has a fast test speed. It is suitable for production control, but it should be noted that the consistency of the sample should meet the requirements of the product standard to avoid errors during the test.
