New steel barrel weld seam coating
Shanghai Xugong Coating Technology (Yantai) Co., Ltd. Bao Dewen
Bao Dewen lectured in the fifth steel drum technical training class
Hello everyone, I am very grateful to the Steel Bar Committee for providing such a convenient platform to exchange ideas with the elites of the packaging and barrel industry here. This time, the products I introduced are dedicated to our 89 series steel drums. Weld repair coating.
Next, we trace the time back to January 1989, in 1989, the special grease-resistant coating for steel drums developed for printing inks. It was successfully developed in Shanghai Xugong Coating Technology Co., Ltd., according to the first name of the surname of Mr. Xu Guoxing. The letter and paint birth day, named X-891 paint. And after several years, he successfully applied for a patent, the patent number is ZL 01 2 45930.5, which is a unique patent product for domestic steel barrel special coatings.
This is a new type developed based on the anti-corrosion advantages of integrated epoxy coatings, PVF coatings, pure phenolic coatings, polyurethane coatings, polyester coatings and amino alkyd coatings, based on the characteristics of steel drum manufacturing and use. Special coating for steel drums. After ten years of use, it has been found that this coating has good oil and chemical resistance. Because X-891 paint can be cured at room temperature without baking, it is more adaptable and used for barrel baking equipment. In terms of cost, it is undoubtedly energy saving and lowering production costs. Soon it was applied to the inner coating of the open steel drum and the outer coating of the electrogalvanized steel drum.
X-891 coating is a two-component room temperature curing coating. The film formation is achieved by the addition and crosslinking reaction of two components in the coating. The reaction can be carried out at room temperature or under low temperature baking. The reaction is a direct addition reaction, the reaction process has no by-product release, and the shrinkage is small, so that the coating has excellent compactness, and the dense network structure coating film has excellent corrosion resistance. It is mainly used in the following aspects:
1. It is suitable for the inner coating of open steel drums and has wide adaptability. It is transparent and has a variety of colors. Its clear coating has excellent cost performance and high transparency and high gloss; white paint has the same visual and tactile feel as white tiles. In particular, the internal coating of domestic large-mouth steel drums has been widely used. After the X891-1 clear coating is applied to the large-mouth steel barrel made of cold-rolled sheet, the inner wall is like a stainless steel mirror panel, which is bright even when placed in a humid and corrosive environment for several years. The X891-1 steel drum special inner coating was successfully applied to the national ink printing special steel packaging steel drum and the internal coating of the chemical protective barrel of the PLA General Equipment Department.
2. The 891 coating can also be applied to the coating applied on the outer surface of the steel drum. When filling steel products with corrosive chemicals, steel drum users will inevitably splash on the surface of the steel drum, causing the paint on the surface of the steel drum to be corroded and peeled off, which affects the appearance and anti-corrosion of the outer layer of the steel drum. performance. Some barrel mills spray a layer of 891 paint on the painted surface of the painted steel drum, which increases the brightness of the outer paint and greatly enhances the corrosion resistance of the outer paint, making the steel drum corroded. In the gas environment, and when the steel drum is filled with corrosive chemical liquid and splashed onto the surface of the steel drum paint, the paint on the surface of the steel drum is still intact. For example, the 890 steel drum anti-corrosion coating was used on the outer layer of the packaging barrel of the German Henkel surfactant.
3, 891 paint can be used as the weld coating and outer coating of ordinary electrogalvanized steel drum, and can also be used for the weld coating of hot-dip galvanized steel drum under normal conditions. Since the zinc layer of the electrogalvanized steel drum is adsorbed by zinc ions under the action of current, the structure of the zinc layer is not as tight as that of the hot-dip galvanized original zinc steel drum, and there is no dense oxide film on the surface of the original zinc steel drum. The oil film, appearance and anti-oxidation and anti-corrosion performance are poor. After coating a thin layer of transparent 891 paint on the outer surface of the electro-galvanized steel drum, not only the overall anti-oxidation and anti-corrosion performance of the electro-galvanized steel drum is greatly enhanced, but also its The appearance is also bright and gorgeous, and it cures quickly after painting. Because it only needs to be coated with a thin layer, the unit consumption is also very low. As a weld coating for electrogalvanized steel drums, it is available in both colorless transparent and silver, and has excellent oxidation and corrosion resistance.
In recent years, as people pay more and more attention to the environment, electro-galvanized steel drums are gradually replaced by hot-dip galvanized steel drums, but the welds of hot-dip galvanized steel drums are always a difficult problem to solve, so many barrel factories will put 891 paints. It has been used on welds and many barrel mills have been used successfully. However, after all, 891 coating is not a special coating for welds. It has the disadvantages of thin coating, low solid content, relatively long curing time and not comprehensive.
Weld seam coating
As hot-dip galvanized steel drums replace electro-galvanized steel drums faster and faster, X-895 (transparent), X-896 (silver) hot-dip galvanized steel barrel weld coatings are based on X-891 coatings and X-897 (hot-melt) hot-dip galvanized steel barrel weld coating was successfully developed by Xugong Coating Technology (Yantai) Co., Ltd., and 895 and 896 were grafted into the polymer epoxy in the resin used in X-891 coating. The resin is formed by addition reaction of another component in the resin, and the solid content of the coating is greatly increased. This greatly improves the water resistance, oil resistance, solvent resistance, rust resistance, water resistance, oxidation resistance and chemical resistance of the coating, and also greatly improves the adhesion to the weld seam, and inherits the characteristics of room temperature curing.
The difference between the two is that X-895 is a transparent EPU weld coating, which is also the exclusive steel barrel weld coating currently produced in China. The appearance is colorless or light yellow liquid. X-896 is a silver EPU weld coating. This product is a modified version of the 895 product. The main difference is that the component A is a silver liquid, which is closer to the color of the galvanized sheet. After painting on the steel barrel weld It is very close to the color of the steel drum itself, which makes the barrel weld natural and beautiful, and improves the overall consistency of the steel drum. Its performance and construction methods are the same as those of 895.
The X-897 coating is a hot-melt coating. When the steel drum is lowered from the seam welder, it is immediately applied to the hot-welded weld. The hot-melt coating is immediately melted and evenly applied to the weld. The chemical resistance of the coatings is also excellent, but it is easy to leave marks after the corrugation and the ribs, so it is best to blow them with 200 ° C hot air after the corrugations and ribs, or after the corrugations and ribs Heat the weld at the weld.
Schematic diagram of the fill coating system in the weld
X-891, X-895 (transparent) and X-896 (silver) coatings are two-component, room temperature curing coatings. Simply mix the two components in a ratio of 1:1 and mix well. After leaving for 10 minutes, the bubbles generated during the agitation disappear and can be used. Spraying and brushing are very convenient, but it should be noted that the mixed paint of the component A and B is preferably used within four hours. After use, the spray gun, pipe and paint brush should be cleaned immediately to avoid curing on the construction tool; In addition, it should be noted that its component B must be stored in a dark, ventilated, dry, cool place, and should be sealed immediately after use.
The film formation of X-891, X-895 (transparent) and X-896 (silver) coatings is achieved by the addition of two components in the coating. The reaction can be carried out at room temperature, usually at room temperature. 891 coatings in the case of full contact with oxygen, dry at room temperature (25 ° C) for 10 minutes, half an hour means dry, the higher the temperature, the faster the curing, but when the temperature is lower than 10 ° C, the curing time is greatly extended, It is generally fully cured in seven days; 895, 896 paint is dry for ten minutes, dry for twenty minutes, and fully cured for four days; of course, if these paints can be baked at 180 degrees Celsius for fifteen minutes, they will solidify immediately. Whether it is curing at room temperature or curing, the curing reaction is a direct addition reaction, and no by-product is released during the reaction, and the shrinkage is small. Therefore, these kinds of coatings have inherited the characteristics of 891 and have excellent compactness. This dense mesh structure coating has excellent corrosion resistance.
Schematic diagram of the external coating roller coating system
The birth of special weld coatings for steel drums paved the way for the development of steel drum coating technology in China. At present, all countries in the world are improving the environmental protection of steel drum coating technology. Among them, technologies such as steel drum color printing and steel drum laminating are gradually popularizing, and China has begun to develop.
Special weld seam coating for steel drums can not only be used for weld seam coating of galvanized steel drums, but also for residual seam welding of color-coated steel drums and coated steel drums. It is a must for future steel drum production. Preparation materials are also the only way to improve the process. This is a new technology, new product and new process that leads the environmental development of steel drums.
Our above product introduction and process parameters have been supported by relevant companies, and I would like to express my gratitude. If there is anything wrong, please Yazheng. For other unfinished issues in the application of weld refill coating products, please feel free to contact us.
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