Insulation material is the basis and guarantee for the development of electrical products. It plays a particularly important role in the development of electrical machinery and electrical industry. The development and progress of insulation materials depends on the development of polymer materials and directly restricts and influences the development and progress of electrical products. .
Insulating materials are the key to the advanced technology of electrical products, and also an important guarantee for the long-term safe and reliable operation of electrical products. Therefore, it is required to continuously develop new varieties of insulating materials and improve product performance and quality to meet the needs of the continuous development of electrical products.
After more than 50 years of development, China's insulation materials industry has initially formed an industrial system with relatively complete products, complete supporting facilities, and considerable production scale and scientific research strength. Especially in the past 20 years, the variety of insulating materials has developed rapidly, the quality has been greatly improved, and the product level has reached a new height.
Before the 20th century, insulating materials were basically derived from natural materials or their products. The earliest electric motors used silk, cotton yarn and cotton cloth as insulation materials. In order to improve water resistance and the like, natural resin such as shellac is impregnated with vegetable oil or pitch.
At the beginning of the 20th century, due to the development of organic synthesis and polymer chemistry, humans made the first synthetic polymer, phenolic resin, which was also an important invention in the field of insulating materials. Once the phenolic resin was introduced, it was quickly widely used, and it was made into a phenolic resin-based impregnating varnish, plastic, impregnated fiber product and laminate. Urea-formaldehyde resins, aniline-formaldehyde resins, melamine-formaldehyde resins, glycerin resins, and the like have appeared in the future.
Since the 1930s, polyvinyl chloride, polyethylene, polytetrafluoroethylene, neoprene, polyvinyl acetal have been developed. After the 1950s, organosilicone, polyester film, unsaturated polyester resin, epoxy resin and other industrial production, while glass fiber, powder mica products began industrial production, promoting the development of insulation materials. With the development of modern polymer chemistry and industry, the development of new insulating materials based on synthetic polymers has really begun. The polymers that appeared in the previous paragraph were successively applied to insulating materials, and rapidly developed new types of insulating materials, such as solvent-free paints for motors.
Impregnation; film composite products as slot insulation of motors; powder mica products are rapidly developed and used in large high-voltage generators; sulfur hexafluoride is available and used in high-voltage electrical appliances.
In the 1970s, while the polymer industry was further developing into large-scale industrialization, the new F-class and H-class insulating material systems began to appear in the insulating materials industry, and polyimide, polyamideimide, and poly were successively developed. Heat-resistant insulating varnishes such as imide, polymaleimide, and polydiphenyl ether, adhesives and films, and modified epoxy, unsaturated polyester, aramid fiber paper and composite materials thereof New product. The heat resistance grade of electrician products has risen to B grade in large quantities, and new F-class and H-class insulation materials have been adopted in special motors such as metallurgy, cranes and locomotive motors.
After entering the 1980s, China carried out large-scale independent development of Class F and Class H insulation materials to improve performance, such as the appearance of modified diphenyl ether, modified bismaleimide, modified polyester Amine enameled wire lacquer, polyamideimide enamel coated wire lacquer, polyimide enamel coated wire lacquer, F grade, H grade glass fiber products, high performance polyimide film, F grade epoxy powder mica tape. Solventless impregnating resins and fast drying impregnating varnishes have developed rapidly. The use of less rubber powder mica tape and VPI (vacuum pressure impregnation) impregnating resin began.
Modern application of nanotechnology to develop nano-insulation materials. Nanotechnology can be used in many fields, including the field of insulating materials. The nano-scale (ranging from 1 to 100 nm) powder is uniformly dispersed in the polymer resin, and it is also possible to form or add nano-scale crystal grains or non-grain substances inside the polymer, and to form nano-scale micropores. Or bubbles. Due to the structural characteristics of nano-sized particles, the composite materials exhibit a series of unique and singular properties, making nanomaterials into a promising new material field. At present, research in this area has been carried out in China. For example, the preparation of polyimide/montmorillonite nanocomposite film by Sichuan University has been successful. The application of nanomaterials is bound to be a new and different performance that many traditional insulating materials cannot achieve, opening up the development prospects of new materials and new technologies.