Among many industrial paints, the adhesion of epoxy zinc rich primers can be said to be very good. However, we often encounter the phenomenon of poor adhesion of the primer and peeling off during construction. This makes people question: Is the adhesion of epoxy zinc rich primer really that good?
To understand this problem, we must first know what factors affect the adhesion of epoxy zinc-rich primers, so that we can solve the problem of poor adhesion in a targeted manner.
There is no doubt that the adhesion of epoxy zinc rich primer is very good. From various construction schemes and construction sites, epoxy zinc-rich primer is the choice of general steel structure primer. So why is the adhesion of epoxy zinc-rich primer worse in some occasions?
1. First, check whether the epoxy zinc-rich primer has expired for too long, or the thinner has been added too much. The general shelf life of paint is one year. If the paint is left on for too long, the paint quality will inevitably change. Add too much thinner or cause the paint to be too thin, and the paint can easily run off, which can be seen during application.
2. During the construction of epoxy zinc rich primer, it is necessary to avoid moisture on the substrate, which requires that it cannot be used in an environment with excessive air humidity, or in some humid areas. When using epoxy zinc rich primer paint, the air humidity should be less than 80%, there should be no water droplets on the substrate, and it should be completely dry. For some very wet and difficult-to-dry substrates, do not use epoxy zinc-rich primers, and can use moisture-curing inorganic zinc-rich primers.
3. The premise of good adhesion of epoxy zinc-rich primer is that the treatment of the substrate is better. The paint has very high requirements on the substrate, and the sanding should be up to sa2.5 level, and there should be no dust or oil stains, which can easily reduce the adhesion of the paint. Therefore, the substrate should be cleaned before construction.
If there is old paint on the substrate, it should be cleaned up, even if the paint film is the best. Paints of different properties react easily, such as between epoxy paint and alkyd paint. Therefore, the general paint construction requires the previous paint layer to be cleaned up.
Poor adhesion of epoxy zinc rich primer paint is rarely due to problems with the paint itself. In most cases, it is a construction problem. Three-point paint and seven-point construction are not casually talked about. From the four influencing factors analyzed above, we can easily see how to solve the problem of poor paint adhesion.