(1) A large amount of dust is generated during the production and coating process of powder coatings. It can be treated by adding dust removal equipment, but some ultrafine dust (usually <10μm) is still discharged into the atmosphere. Dust and noise during the production process often become factors that disturb the public. In this context, it is a general trend for powder coating companies to enter chemical parks. As the deadline for coating companies to enter chemical parks approaches, some non-standard powder coating companies will also face a survival crisis.
(2) Item 485 of the "Environmental Protection Comprehensive List (2017 Edition) (Draft for Comments)" recently issued by the Ministry of Environmental Protection lists powder coatings containing TGIC curing agent as "double high" (high pollution, high environmental risk) products. Although there are some "TGIC-free" products on the market, such as HAA (commonly known as Primid products) and PT910. and HAA is the most mature TGIC alternative product on the market, to this day, its performance indicators such as heat resistance and thick film are still not comparable to TGIC coatings. Some alternative products only reduce toxicity (such as MT239), but also reduce the activity of the curing agent. Therefore, there is no complete TGIC alternative product at present.
(3) The powder coating industry still uses a large amount of lead chrome yellow and molybdenum chrome red pigments. These heavy metal-containing pigments may cause harm or potential danger to the human body. Developed countries have laws to restrict the use of toxic and hazardous substances. For example, North America, Europe, Australia, New Zealand, Japan, and South Korea have legislated to limit the content of lead in coatings. my country's legislation on restricting the use of heavy metal pigments in coatings will also be increasingly improved. However, high-cost alternatives (such as high-performance organic pigments, metal mixed phase pigments, ceramic pigments, etc.) make the already overburdened powder coating production cost control even worse. But it is gratifying that the replacement of these pigments is a problem that the entire coating industry needs to face, not just a problem of the powder coating industry. I believe that with collective efforts, there will be a solution.
(4) The curing of powder coatings requires high temperature conditions. The latest powder coating technology must also be cured at above 120°C. High-temperature curing consumes more energy and is at a disadvantage compared to other coatings in terms of energy saving.
(5) Most non-metallic substrates, such as concrete and stone, cannot be powder coated for corrosion protection at present, but technical breakthroughs have been made on some plastic substrates and MDF boards, and powder coating on non-metallic substrates is expected in the future.
(6) It is also difficult to achieve powder coating for very large metal parts (such as steel structures, containers, etc.) or metal parts with extremely complex shapes. For large workpieces, to achieve powder coating, an extremely large curing device is required, which is unrealistic. The revolution of coating equipment in the future is expected to solve the problem of coating large workpieces, such as flame spraying. In addition, for workpieces with particularly complex shapes, the "Faraday cage" generated during powder electrostatic spraying makes it difficult for complex internal corners and grooves to absorb powder, and the coating effect is unacceptable. Only environmentally unfriendly hot-dip galvanizing or cold-dip galvanizing processes can be used for corrosion protection. In the future, the coating of these complex workpieces can consider the application of powder fluidized bed technology to solve the "dead zone" coating problem on the workpieces. This requires the joint efforts of coating companies and coating equipment manufacturers to overcome difficulties.
(7) Powder coatings have received too little attention in the overall coatings industry. The attention and research enthusiasm of colleges and universities and research institutions for powder coatings are far lower than other environmentally friendly coatings such as water-based and high-solid coatings. At present, there is no special powder coating major, and the coating major in colleges and universities rarely involves powder coating knowledge. This may be because powder proofing research and development requires a complete set of small production equipment, while liquid coatings can be carried out with only small test devices such as polymerization bottles. In addition, powder coatings do not seem to belong to the "famous and upright" in the coatings industry, because the powder form is more similar to ultra-fine plastic particles, that is, "plastic powder", rather than the form of "coating concept"; its processing method and some additives and pigments used are more similar to plastic processing, especially thermoplastic powder coatings. Powder coatings are a school of their own in the coatings industry, lacking overall interaction with the coatings industry, which is not conducive to the advancement of powder coating technology.
(8) There are many private powder coating companies that are eager for quick success and quick profits. Long-term vicious competition with low prices is not conducive to the long-term development of powder coatings.
