Hardener is also called curing agent or modifier. Topcoat curing agent is a substance that accelerates the stability of topcoat. It will have a certain effect on the surface gloss of topcoat. For industries with high requirements, it is necessary to strictly measure the gloss change before and after the topcoat curing agent is used. If after using the topcoat curing agent, the topcoat gloss does not meet the requirements, you need to adjust the topcoat curing process.
Paint surface gloss is the visual impression obtained when evaluating a surface. The more light directly reflected, the more obvious the gloss feeling. Gloss mainly depends on the specular reflection ability of the object surface and has a certain relationship with the surface roughness. The curing of paint is a chemical process such as condensation, closed-loop, addition or catalysis, which causes the thermosetting resin to undergo an irreversible change process. This process will affect the paint structure and the surface flatness.
With a precise gloss meter, the gloss before and after the curing process of the topcoat can be detected. Through comparative analysis, a more suitable topcoat curing agent can be selected. In order to better detect and control the change of gloss before and after curing, we can use Linshang gloss meter.
Most gloss meters measure the surface reflectance of an object, which is called a specular gloss meter. The measurement results are different depending on the angle of incidence selected during the measurement. The larger the angle of incidence, the greater the specular reflectance and the higher the gloss. That is why high-gloss materials should be measured with a high-gloss measuring instrument at a 20-degree angle; otherwise, the lower the specular reflectance, the lower the gloss. Use a gloss meter with an 85-degree angle. It can be seen that the level of gloss depends not only on the surface characteristics of the object, but also on the measuring angle of the instrument.
Therefore, it is best to use the same gloss meter when testing the gloss of the topcoat curing agent before and after curing. A single set of data is difficult to support the effect of the topcoat curing agent on gloss and multiple experimental tests should be performed.
Like Linshang universal 60-degree gloss meter LS192, with a measurement range of 1000GU, both high-gloss and low-gloss cured paint can be tested, because gloss is a relative value. It can be used when there is no uniform standard in the applied industry. If the industry has a uniform standard, it is best to use the same angle of testing. Therefore, when selecting the measurement angle, you should choose differently according to different situations.