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On the Bottleneck Period of Epoxy Primer for Color Coated Board

Update:11 Jan 2020
Summary:

With the rapid development of the color coated plate in […]

With the rapid development of the color coated plate industry, the development of color plate coatings with excellent performance to meet the needs of advanced and diversified products has become a hot topic at home and abroad. Among them, the formulation of a primer with good adhesion and flexibility, and good matching with the topcoat is very important to improve the performance of color plate coatings. The electro-galvanized sheet is used as the substrate, and the product obtained by baking with organic paint is an electro-galvanized color-coated sheet. Because the zinc layer of the electro-galvanized sheet is thin, the zinc content is usually 20 / 20g / m2, so this product is not suitable for use Make walls, roofs, etc. outdoors. However, because of its beautiful appearance and excellent processing performance, it can be mainly used in home appliances, audio, steel furniture, interior decoration and so on.
Because there are many influencing factors, the preparation of the primer is a complicated process. Recently, domestic researchers have used orthogonal experiments to determine the influence of various factors on the performance of epoxy primers, so that the optimal formula can be reasonably determined in fewer steps. Advantages and excellent adhesion performance. According to experts, they focused on six factors affecting the selection of the base-to-base ratio, the amount of cross-linking agent, the catalyst, the defoaming agent, the surfactant reducing agent and the wetting and dispersing agent. The cross-linking curing agent selected was urea-formaldehyde resin SM-526. Experiments have shown that the amount of cross-linking curing agent has the greatest influence on the adhesion of the paint film, and also has a large effect on the bending and MEK resistance. It has no significant effect on the hardness of the paint film.Due to the variety and quality of domestic coil coatings lagging behind foreign products, Chinese manufacturers have to use expensive imported coatings when producing color plates, which greatly affects the development of China's color plate industry. For this reason, experts call for the domestic industry to break through the bottleneck of epoxy primer for color coated boards as soon as possible.
At 15%, except for the same hardness as the other 3 levels, other properties are poor; at 20%, the MEK wipe resistance and bending performance are the best, and the adhesion is average (average 1.3); at 25%, the MEK wipe resistance of the paint film And the best hardness, the other two properties are poor. In consideration of the processability of color plates, the researchers chose to use 20% of the crosslinking curing agent. Experts said that the above research has made a good start, but further research is needed to truly break through the bottleneck of epoxy primer for color coated boards. In the experiment, the influence of the four kinds of dosage on the hardness is not obvious (the average value is 5.0); the adhesion is the best when the amount of cross-linking curing agent is 10% (the average value reaches 0.3), the MEK resistance is relatively poor, and the bending performance is better .

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