The paint adhesion of steel drums is in accordance with the provisions in Appendix A of GB325-2000 “Drums for Packaging Containersâ€, which is qualified by reaching the second level according to the cross hatching method. However, in the course of using the actual users, this level is not up to the requirements. The customer's requirements are much higher than this level. In the course of use, some customers require that the film be wetted by rain, the film adhesion must still reach more than one level, and individual customers will soak the cover of the steel tub with water. After 2-3 hours of draining the water, the adhesion of the paint film is still required to reach more than one level. This has brought new research topics to the manufacturers of steel drums, namely how to further improve the adhesion of paint film on the drum surface. There are also requirements for the paint itself. The dry paint film must have strong water resistance when it is flooded, not softened by water, and the paint film must be dense. There should be no fine pores to ensure that the water does not follow. The pores of the paint film penetrate between the paint film and the steel drum and play a role in the separation between the two. Here are a few points about several aspects that affect the adhesion of paint film on the surface of steel drums.
First of all, the surface of the treated steel drums before the steel drums is oil-free, rust-free, and phosphatized. This is already known to those who produce steel drums. Now we want to talk about one detail, that is, washing after phosphating, After the phosphating of steel drums must be fully washed, it is best to often run water, do not use recycled water, if you use recycled water, but also after processing can be recycled, otherwise, washing is not clean, some of the salt surface after drying The fine particles are attached to the surface of the steel drum. Before the spraying, the steel drum is horizontally dried. You will see a circle of water marks on the surface of the drum. The paint will spray on the fine particles when spraying. Attached to these granules, the adhesion is greatly reduced, and when the external force or bad weather is encountered, the paint film sprayed on the fine particles will fall off.
Second, the temperature and time of paint drying
Domestic steel drum manufacturers need to use a certain amount of energy in order to reduce energy consumption and save production costs in the form of electricity, fuel oil, natural gas or coal. All manufacturers are in the drum paint film. Baking temperature and time work hard, some manufacturers use slightly increase the drying temperature, to shorten the drying time, and some manufacturers do not even increase the paint drying temperature and shorten the drying time, this practice makes the film only The surface is dried and not dried, and the hardness of the paint fails to reach the hardness when it is dry. When there is impact and bump, the paint film will be scratched or partially peeled off.
Dry paint has a good waterproof performance, a certain degree of hardness, but also requires a certain degree of toughness, brittle paint film will peel off.
Again, storage environment and transportation conditions
In short, in the steel drum production process, the washing line, the spraying line, and the drying line are operated as a whole. If there is a problem in a certain part and the production is stopped, the other production lines are also stopped accordingly. In order to ensure the quality of the paint film, it is not allowed. There is a production line that is sick.
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