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The basic composition of powder coatings is composed of resins, curing agents, pigments and fillers, additives, etc. The quality of the coating film depends on the formulation composition, processing methods and coating conditions, so the powder coating formula is different according to the specific conditions.However,no matter how it changes, the basic composition ratio is similar.
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Resin, which is divided into two types of thermoplastic and thermosetting, is one of the main components of powder coatings. It plays the role of film formation and uniform color displayed, and can be well attached to the substrate,thermoplastic such as polyamide, polyolefin, polychloride Ethylene, polyester, polyvinylidene fluoride, etc, thermosetting such as epoxy, polyester, pure polyester, acrylic, polyurethane, etc.
Curing agent is used in thermosetting powder coatings. During the coating construction process, when reaching at a certain curing condition, it will chemically crosslink with the resin to form a body structure, thereby obtaining a coating film with excellent performance. Generally, curing agent can be roughly divided into three series in line with resins, namely, epoxy curing agent, polyester curing agent, and acrylic curing agent. Generally, the curing agent should be powder, flake or granular light-colored solid.
As an important component of colored powder coatings, pigments are mainly used to cover, decorate and protect the coated object. Generally,powder (or granular) of pigments, insoluble in the base material, are colored substances with optical protection and decoration functions, which can be divided into organic pigments and inorganic pigments. The filler is an inorganic substance that meets the conditions of inactive chemical properties, good stability to light and heat, and does not have covering power and coloring power. Common fillers include barium sulfate, calcium carbonate, talc, wollastonite, and titanium dioxide. It plays a skeleton role in powder coatings, enhances the performance of the coating film, can also reduce the production cost of powder coatings, and can also increase the powdering rate and spraying area of the powder.
In addition to the above main base materials, there is another important substance that obviously affects the appearance and curing degree of powder coatings additives. Powder coating additives are specially used in powder coatings, which is a chemical product to obtain special application performance obtained of coatings by the smooth production of polymer base materials. Powder Coatings Auxiliary can generally be divided into two types: one is to only change the physical properties of the polymer without changing the chemical structure of the polymer, such as defoamers, dry powder flow promoters, etc.; It is the chemical structure of the polymer that has changed more or less, such as curing agents, reactive matting agents, and so on.
Main Application Scope of Powder Coatings
1. Construction industry: in steel doors and windows, hardware, door fittings, explosion-proof doors, anti-theft doors, indoor metal ceilings, ceiling panels, street signs, highway signs, aluminum profiles
2. Pipelines: petroleum transportation pipes, water pipes, sewage pipes, marine pipes, chemical anti-corrosive pipes
3. Automobiles and parts: minivans, buses, tractors, auto parts (including seats, wipers, horns, handles, bracket chassis, baffles, automobile engines, wheels, filters, joysticks, etc.)
4. Metal furniture: office cupboards, writing desks, chairs, beach chairs, iron beds, safes
5. Home appliances: refrigerators, washing machines, air conditioners, microwave ovens, electric fans, sewing machines, lighting
6. Electronic components: capacitors, motor rotors, transformers, coils, instruments and meters, power distribution cabinets
7. Bicycles, motorcycles, complete vehicles and parts, other electromechanical
8. Metal wire mesh and various net rack products: refrigerator shelves, supermarket shelves, bicycle net baskets, etc.
9. Railway, aviation, medical equipment, etc.
?Powder?Coating?Application in Furniture and Household Electrical?Industry
In recent years, due to the rise of household electrical and furniture industry, powder coatings have entered the household electrical market with their bright colors, sturdiness and durability. At the same time, with the complete supporting of powder coating raw materials, production equipment, testing instruments, and spraying equipment,powder coatings industry in China has achieved unprecedented development. It has made great progress in terms of variety, quantity, quality, application and people's cognition. The output in 2003 is nearly 340,000 tons , with an average annual growth rate of more than 15% has become the world's No. A large manufacturer of powder coatings.
?Powder Coatings in the Automotive Industry
Automobile industry is a pillar industry in China. The investment in the next five years is equivalent to 9 times of the 1985’s Plan period. In 2005, the social ownership of automobiles in China will reach 20.6 million. At present, powder coatings are mostly used in the coating of automobile engines, chassis, wheels, filters, joysticks, mirrors, wipers and horns in the automobile industry. In overseas countries, transparent powder coatings have been used as overcoats for car bodies and other vehicles. Automobile assembly plants are also gradually expanding the application of powder coatings. Due to technical limitations, the current knowledge of automotive powder coatings is a monochrome series. In the future, the development of automotive powder coatings will further improve after-resistance, UV resistance, low temperature, thinning and improve decoration. With the development and application of new technologies and stricter environmental protection requirements,it will further expand for the application of powder coatings in the automotive industry .??
?Attractive Prospects for Powder Coatings in Shipbuilding and Pipeline Industries
Acher, chairman of the German Shipbuilding and Marine Technology Federation, pointed out that from now to 2005 will be a period of great development in the world's shipbuilding industry, and the demand for all types of ships in the world will get an great increase by 50%. China is a big ocean country, as well as a great country in shipping and shipbuilding.The steel pipes on ships are distributed in various systems. According to their functions, they can be divided into: seawater pipelines, freshwater pipelines, steam and wastewater pipelines, fuel and oil pipelines, sewage pipelines, etc., generally,when one ship reaches 10,000 tons level, the total length of pipelines systems can reach 30000m. At present, powder coating spraying has been applied to some ship pipelines, and the development momentum is very strong. With the continuous improvement of powder coating technology,it has a very broad development.
?Application of Powder Coatings for Construction Projects and Outdoor Facilities.
In 1913, the United States used epoxy powder coating concrete bars in the construction of the Pennsylvania Bridge. It was found that epoxy powder greatly increased the service life of the concrete bars, effectively protecting the building, and more than doubled of the expected service life.
Powder coating has successfully entered the construction field, such as powder coating of aluminum profiles, aluminum alloy ceilings, security doors, aluminum alloy curtain wall panels, etc. At present, the domestic construction area has 500 million square meters each year. It is beyond all doubts that powder coatings has potential huge business opportunities.?
