Application status and Prospect of high temperatur

2022-09-21
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Application status and Prospect of high temperature resistant coatings for modern small household appliances

application status and Prospect of high temperature resistant coatings for modern small household appliances

November 11, 2019

broad market demand and high profits have promoted the rapid development of the small household appliance industry. Production lines have been spread throughout rice cookers, electric magnetic furnaces, electric frying pans, hair dryers and electric kettle, and small household appliances have become a necessity for today's families. Most small household appliances work in high temperature environment. In order to better protect their working parts, the basic properties of high temperature resistance and wear resistance are also proposed for the coating. At the same time, better decorative and other properties can also better meet the market demand for coatings

Yu Kai said that silicone coating

silicone coating is the earliest and most widely used high temperature resistant coating for small household appliances in China. It has a wide variety and mature preparation technology. Organosilicon coating is mainly composed of organosilicon resin. The organosilicon resin has a complex staggered structure with sample specifications, stable chemical properties and good high temperature resistance. The working temperature of most small household appliances is usually below 300 ℃, and the maximum temperature resistance of silicone coating can also reach 300 ℃. From the perspective of temperature resistance, silicone coating is a very suitable high temperature resistant coating for small household appliances

in order to meet the actual needs of a small number of small household appliances whose working temperature exceeds 300 ℃, the coating manufacturer has modified the silicone coating. The basic modification principle is to reduce the content of hydroxyl and other high-temperature resistant components, increase the proportion of Si-O-Si bond and inorganic salt high-temperature resistant components. Combined with the advanced processing technology of modern composite materials, the high-temperature resistance effect of silicone coating has been significantly improved, even up to 600 ℃

silicone coatings not only have good high temperature resistance, but also have strong adhesion, high coating hardness, simple application process and low cost. These advantages make silicone coatings shine in the domestic small household appliance market and are favored by small household appliance enterprises. However, the shortcomings of silicone coatings are also obvious, mainly in the following aspects:

(1) back adhesion phenomenon. The coating prepared by silicone coating intensifies the molecular thermal movement at high temperature, and the structure will soften. When contacting with sharp objects, the silicone coating attached to the surface of small household appliances is prone to scratch and other damage to the coating

(2) safety problems. There are some toxic components in the silicone coating, which will gradually diffuse from the interior to the surface through infiltration, especially the coating directly in contact with food, which may have potential food safety hazards

(3) ultra high temperature resistance. With the further improvement of the service temperature of some household appliances, the working temperature of small household appliances is even as high as 600 ℃. How to further improve the service temperature of silicone coating has become an urgent problem to be solved. At present, a few large-scale silicone coating manufacturers with R & D strength in China are conducting relevant research and have made some progress, but there is still a distance from practical application

fluorocarbon coating

fluorocarbon coating, as a new material, although its practical application time at home and abroad is not long, its excellent high temperature resistance, strong corrosion resistance, self-cleaning, strong adhesion and super weather resistance have attracted extensive attention. The main component of fluorocarbon coating is fluororesin, which has very stable chemical properties and excellent high temperature resistance. Small household appliances coated with fluorocarbon paint can be used continuously at 260 ℃ without change, and fluorocarbon paint is insoluble in oil, will not react with food, and has good safety

fluorocarbon coating has obvious advantages, but its disadvantages are also prominent. Its shortcomings are mainly manifested in its own temperature resistance, hardness and construction. The hardness of fluorocarbon coating under normal temperature is only h, that is to say, the fluorocarbon coating under normal temperature does not need a shovel, steel wire brush, and even can scratch the fluorocarbon coating only with fingernails. For example, the fluorocarbon used in electric irons is now used by Inner Mongolia (Naiman) Jing'an nonferrous metal materials Co., Ltd., Inner Mongolia Shangtai Industrial Co., Ltd The capacity replacement plan of the construction project of Inner Mongolia Hangfeng Special Alloy Co., Ltd. is announced. The coating is often scratched and damaged by sharp objects such as buttons. Fluorocarbon coating can work stably at 260 ℃, and it is easy to melt above this temperature. The low hardness of fluorocarbon coating determines that the construction of fluorocarbon coating is difficult and the process conditions are difficult to control. How to maintain the adhesion and smoothness of fluorocarbon coating in the bonding process is particularly important

future development direction of high-quality fluorocarbon coatings:

(1) solve the current problems of solvent based high temperature resistance, hardness and harsh construction conditions

(2) green environmental friendly waterborne fluorocarbon coating

(3) nano materials are compounded with fluorocarbon coatings to improve the density and other comprehensive properties of the coatings

powder coating

powder coating has been widely recognized as "4E" (efficiency, excellence, economics and economy) coating because of its advantages of no organic solvent, no pollution, high utilization rate and low energy consumption. Powder coatings can be divided into thermoplastic powder coatings and thermosetting powder coatings according to different film-forming substances. Thermosetting powder coating is usually used in small household appliances. Its principle is to use resin with small molecular weight and curing agent to cross-link at high temperature to form macromolecular coating. Polyester powder coating, acrylic powder coating, epoxy powder coating and polyurethane powder coating are widely used in the field of small household appliances

powder coatings have developed rapidly in recent years, with more and more types and excellent properties. Compared with low-cost small household appliances, the use cost of powder coatings is still very high. It is hoped that coating manufacturers can develop low-cost and high-performance powder coatings suitable for small household appliances

at present, UV curable coatings with all switches turned off (UV) have also appeared in the market. The principle is to use UV light-emitting initiators to crosslink unsaturated bond groups in photosensitive resins to form body structure coatings. Although the production process of UV curable coating is simple, it can not be widely used in the field of small household appliances due to its high price and poor thermal stability

source: Proceedings of 2019 China powder coating and coating industry annual meeting

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