In our canning process, use of pre-printed inside the tank iron approach within the coating composition for the food liquid coatings, printing iron when welding seam at the left side to give generally more difficult to stay within the coated side, before many factories seam welded to scraping edge treatment, so as not to affect the weld seam quality. But in the weld seam after welding but also for touch up process is more complicated, but also in quality assurance is not easy. In recent years, the growing popularity of powder paint coating process is increasingly being applied to the canning industry, the canning industry, the powder coating process, while not any new technology, but people really started to pay attention to it is near a few years ago. As early as 20 years ago, the United States, the weld on the inside of the three-piece cans powder coating process has been used for production. Since the powder paint coating is thicker than the paint coating the coating liquid, so the use of powder coating process can more effectively prevent the influence of iron smell of canned food taste and color. At present, the world has at least 800 canning production line using powder coating technology for the production of weld inside.
Currently, the process in the field of canning industry in the application is true cans coating repair and paint the inside of the three-piece cans. After a number of scientific tests show that the coating effect powder coatings are ideal, the use of powder coating products can be used to deal with a variety of canned food, beer, beverages, and aerosols. Some people think that, within a decade, powder coating process will increasingly be applied to the two-piece cans and beverage cans.
Why powder coating process so attractive it? Because the use of more environmentally friendly powder coating, highly reliable environmental performance, but also has good economic benefits. Powder coating is 100% solid material, and liquid paint compared to, in addition to the absence of solvent, the composition exactly the same. When the body is placed in a heated oven, the powder melts to form a continuous film.
Most canning industry uses powder coatings are epoxy or polyester, varnish or paint modification treatment. Coating utilization is very high, so the loss is very small, especially recycling system to collect overspray powder, and the powder overspray adjustments, re-enter the system recycling.
Because the powder coating is solid, so the use of the process such as recycling and clean purify, transport and processing are in the solid state. By powder coating process does not produce liquid coating exist loss, but the loss of the liquid coating is difficult to be controlled, and expensive.
Powder coating in the next few years, could be one of a large number of applications, coating technology. Because of the dry powder coating is 100% solid state, thus in line with the global levels of government to reduce or prohibit the use of VOC paint requirements. For each canning production plant, the use of solvent-free powder coating is one of the tank surface treatment processes effective ways to prevent volatile organic compounds.
For environmental protection, the use of powder coating process of cans and lids, not only beneficial to manufacturing plant, also advantageous for food packaging manufacturers. In order to meet customers' increasingly high quality of the product packaging requirements, food packaging plant has been seeking different, unconventional means of settlement. This canned food containers both meet environmental safety requirements, and easy to produce. If just from the marketing point of view, the use of powder coating process can canned container bottling plant to establish a model of environmentally friendly image. As the flow of environmentally friendly products on the market, the market is very strong sales.
The current new cans closures and three cans of coating repair equipment are based on full automatic control system. Typical powder coating system is the powder made from the powder feeder supply station sucked out, transferred to the recovery, the recovery and recycling of the original powder mixed powder, then mixed with air, and delivered by a pump system to friction gun . When the powder is transferred to the container body or the lid, the gun by friction electrification, electrostatic charge to bring the powder particles, the powder charge in a special way adsorbed onto a uniform spray cans or lids and spray paint all over it full access to the recirculating means is recovered, adjusted and re-use.