A brief history of insulation development
Insulation material is the basis and guarantee of the development of electrical products, and plays a particularly important role in the development of electrical machinery and electrical industry. The development and progress of insulating materials depend on the development of polymer materials and directly restrict and affect the development and progress of electrical products.
Insulation material is the key to advanced technology of electrical products, and it is also an important guarantee for long-term safe and reliable operation of electrical products. Therefore, insulation materials are required to continuously develop new varieties, improve product performance and quality, so as to meet the needs of the continuous development of electrical products.
After more than 50 years of development, China's insulation industry has initially formed an industrial system with complete products, complete supporting facilities, and considerable production scale and scientific research strength. Especially in the last 20 years, the variety of insulation materials has developed rapidly, the quality has been greatly improved, the product level has reached a new height.
Until the 20th century, insulation was mostly made from natural materials or their products. The earliest electric motors were made of silk, cotton and cotton. In order to improve water resistance, natural resin such as shellac is used to impregnate vegetable oil and asphalt.
In the early 20th century, thanks to the development of organic synthesis and polymer chemistry, the first synthetic polymer, phenolic resin, was made. It is also an important invention in the field of insulating materials. Phenolic resin has been widely used since it came into being. Phenolic resin based impregnating paint, plastic, impregnated fiber products and laminated products have been made. Later appeared urea formaldehyde resin, aniline formaldehyde resin, melamine formaldehyde resin, glycerin resin.
Since the 1930s, the development of polyvinyl chloride, polyethylene, teflon, neoprene rubber, polyvinyl acetal and so on. After the 1950s, the industrial production of silicone resin, polyester film, unsaturated polyester resin, epoxy resin and other industrial production, at the same time, glass fiber, mica products began to 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 really began. The polymers in the previous paragraph were applied in insulation materials one after another, and new insulation materials were rapidly developed. Thin film composite products as the motor groove insulation; Mica products developed rapidly and were used in large high voltage generators. Sulfur hexafluoride appeared and was used in high voltage electrical appliances.
Into the 1970 s, the polymer industry at the same time in the further to the development of large industrial, insulating materials industry began to appear the new F, class H insulation system, have developed the polyimide, polyamide imide, polyimide, poly (maleic imide, diphenyl ether and other heat resistant insulating paint, adhesives and film, as well as the modified unsaturated polyester, epoxy, aromatic polyamide fiber paper and its composites, etc. Series of new products. Electrical products in a large number of heat-resistant grade B, in metallurgy, crane, locomotive motor and other special motors began to use new F class, H class insulation materials.
After entering the 1980 s, China's own development on a large scale of F, H insulation materials, the performance is improved, such as the modified diphenyl ether, modified double maleic imide, modified polyester imide enameled wire paint, polyamide imide enameled wire paint, polyimide enameled wire paint, F, H, glass fiber products, high performance polyimide film, F epoxy powder, mica tape, etc. Solvent-free impregnating resins and quick-drying impregnating paints have developed rapidly. Less mica tape, VPI (vacuum pressure impregnation) impregnated resin began to be used.
Modern application of nanotechnology to develop nano insulation materials. Nanotechnology can be used in many fields, including insulating materials. Nanoscale powder (ranging from 1 to 100nm) can be evenly dispersed in polymer resin, and nanoscale grain or non-grain material can be formed or added inside the polymer, and nanoscale micropores or bubbles can also be formed. Due to the structural characteristics of nanometer particles, composite materials show a series of unique and exotic properties, which make nanometer materials develop into promising new materials. At present, researches in this field have been carried out in China. For example, polyimide/montmorillonite nanocomposite films have been successfully prepared in sichuan university. The application of nanomaterials will open up the development prospect of new materials and new technologies for many new and different properties that traditional insulating materials cannot achieve.