Epoxy coating baking techniques

How can we both save energy and ensure the baking quality of epoxy coatings

Epoxy coating is one of the most excellent coatings for metal, and is also the earliest and most common internal coating used in the domestic steel barrel industry. One of the main film forming materials for epoxy coatings is epoxy resin.

The reactive epoxy group in the epoxy resin structure can be cross-linked and cured with various organic compounds to form a strong three-dimensional network structure. Epoxy-based coatings use this property of epoxy resin to make a variety of coatings with different properties. Among all the materials that can be cross-linked and cured with epoxy resins, the epoxy resin and cross-linked butanol-etherified phenolic resin form the best coating and corrosion resistance. However, the cross-link curing reaction between epoxy resin and butanol-etherified phenolic resin must be started above 180°C, and if it is only this temperature, it must be maintained for more than 45 minutes. The cross-link curing reaction under this condition can ensure that only three parts of water are released, no other by-products are released in the process, the shrinkage is small, and the cross-linked and cured can have a good and firm dense mesh structure film. This can further enhance the coating's adhesion, mechanical properties, corrosion resistance and chemical resistance.

However, the problem is that such reaction conditions cannot be met by our steel drum industry. Therefore, most of the barrel plants use a method to increase the temperature and shorten the time. However, due to the differences in the baking equipment and baking conditions of each barrel factory, It is also very difficult to detect whether the epoxy resin and the phenolic resin are completely reacted under such temperature and time conditions, so it is difficult to ensure that the crosslinking reaction is complete, and it is difficult to ensure that the performance of the epoxy coating is fully reflected.

How can we not only ensure the complete reaction of epoxy resin and phenolic resin, but also enable the reaction conditions to be effectively controlled. Adding 5% of the 1491 accelerator to the epoxy coating allows the epoxy resin and phenolic resin to react completely at 180°C for 15 minutes (if the temperature exceeds 210°C, the reaction can be completed in 2 minutes). In this way, not only can the baking conditions of the epoxy coating be effectively controlled, the performance of the epoxy coating can be ensured, but also the baking temperature can be reduced, energy can be saved, and the barrel plant without high-temperature baking conditions can also be produced. Epoxy coated steel drums.

Source: China Tinplate Printing Network