Basic introduction Chinese name: insulating paint mbth:aliquametate insulation interpretation: the general name of colloidal solution of film-forming substances in solvents Pinyin: Jueyuanqi field: energy discipline: electric power, materials:: Introduction, That is, application classification, layer curing mechanism, heat resistance classification, composition of insulating paint, base material, flame retardant, pigment, filler, curing agent, additive, solvent, requirements, application classification, impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint, anti-corona paint, acetal paint, weldability, classification, other products and the development trend of insulating paint at home and abroad. The electric insulating paint is briefly introduced. IEC (International Electrotechnical Association) defines dielectric as a polarizable substance, and electrical insulating material as a material with low conductivity, which is used to isolate conductive parts with different potentials. Including insulating paint, impregnated fiber, laminated board, mica products and pressed plastics. Insulating paint, also known as insulating coatings, is a kind of paint with excellent electrical insulation. It has good electrochemical properties, thermal properties, mechanical properties and chemical properties, and is mostly used in varnishes and paints. With the development of science and technology, people gradually realize that insulating materials are indispensable materials for electrical equipment, and their quality is good or bad. Amine adducts, acid drunk derivatives, synthetic resins and other curing agents are added. The economic and technical indicators and operating life of electrical equipment play a key role. In the flame retardant coating based on vinyl resin, it is compared to "the heart of the motor" to add a proper amount of people. Peroxide as initiator. 1907, Becker developed phenolic resin, which marked the birth of electrical insulation materials. Since 1930s, synthetic resins such as acetal resin, neoprene, polyvinyl chloride, polybutene and styrene-butadiene rubber have been synthesized. In the 1940s, the synthesis and industrial production of silicone resin developed H-class insulation materials based on silicone resin. Subsequently, insulating materials such as unsaturated resin and epoxy resin developed rapidly in the 1960s and 1980s, and insulating paints were generally divided into three types. That is, the uses are classified into enameled wire insulation paint, impregnated insulation paint, coated insulation paint, silicon steel sheet insulation paint, adhesive insulation paint and electronic component insulation paint. Layer curing mechanism: dry insulating paint, dry insulating paint and ultraviolet curing insulating paint. Heat-resistant grades are divided into seven categories: Y, A, E, B, F, H and C. Composition of insulating paint Insulating paint consists of binder, flame retardant, curing agent, pigment and filler and solvent. The base material consists of poly-cool resin, poly-phthalimide acetate resin, polyurethane, epoxy resin, bismaleimide resin, silicone resin and other resins. Flame retardant flame retardants are divided into reactive flame retardants and additive flame retardants; It can be divided into inorganic flame retardant and organic flame retardant according to the components. The purpose of adding pigments and fillers to pigments and fillers coatings is to improve the performance of coatings and prepare them into the required colors. Commonly used pigments and fillers include cyanine white, iron oxide red, carbon black, chrome yellow, mica powder, talcum powder, barium sulfate, calcium carbonate, silicon dioxide and so on. Curing agent Curing agent (or initiator) is an indispensable component of most insulating coatings. In the flame retardant coatings based on epoxy resin, curing agents such as amine adducts, acid drunk derivatives and synthetic resins must be added; In vinyl resin flame retardant coatings, proper amount of peroxide should be added as initiator. Additives Additives are one of the indispensable components for manufacturing, storage, construction and performance improvement in insulating coatings, and are the auxiliary components of raw materials. It plays a special role in coatings and plays a very important role in the film-forming process and durability of substrates. According to its action mechanism, it is mainly divided into curing accelerator, surfactant, rheological regulator, stabilizer and antioxidant. Curing accelerator can reduce curing temperature, accelerate curing speed and reduce exothermic peak of curing reaction. Commonly used curing accelerators are Lewis acid, Lewis base and shuttle acid salt. As a medium for manufacturing coatings, solvents can adjust the construction viscosity of coatings to meet the construction performance. The solvent in the coating should not react with the coating components, that is, the solvent used should be relatively inert. Commonly used solvents are aromatic hydrocarbons, alcohols, fibrinolytic agents, ketones and vinegar. Self-drying insulating paint refers to insulating paint that can be dried into a film by itself after brushing. The mechanism of self-drying is generally divided into three categories: one is volatile drying, that is, the solid resin with high molecular weight is dissolved in an appropriate solvent, and the solvent volatilizes after coating, leaving the solid film-forming resin. This insulating paint is easy to apply and dries quickly. However, it has poor solvent resistance and is easy to soften when heated. The second category is oxidative drying. This insulating paint contains dry vegetable oil, and the unsaturated double bonds in the molecular structure of dry vegetable oil will self-oxidize and cross-link under the action of oxygen in the air, thus achieving the purpose of drying. Generally, oily, phenolic resin and drying oil alkyd resin insulating paints belong to oxidation drying insulating paints. This kind of insulating paint belongs to Class A and E insulating materials because of its high vegetable oil content and low heat resistance. It takes a long time to dry, usually one day. The third is curing and drying at room temperature. This insulating paint is crosslinked and cured by chemical reaction at room temperature. This kind of coating is two-component or multi-component, and now it is ready-made. Such coatings are commonly used, such as polyamide resin cured epoxy resin coatings and two-component polyurethane coatings. This coating is chemically crosslinked, so it has good heat resistance, solvent resistance and chemical resistance. Insulating paint, commonly known as: Fanlishui (self-drying, drying, solvent-free) insulating paint is based on polymer, ZS- 109 1 high temperature resistant ceramic insulating coatings. Coatings can be divided into solvent-based with temperature resistance below 600℃ and water-based with temperature resistance of 600- 1700℃. The coating can form a ceramic coating with high volume resistivity on the surface of the coated object and can withstand strong electric field without being broken down. The coating has high mechanical strength, good chemical stability, aging resistance, water resistance and chemical corrosion resistance, as well as mechanical shock and thermal shock resistance. The coating can work continuously at the corresponding working temperature. The most fundamental thing is to rely on strong technological innovation ability and make full use of the latest scientific and technological achievements in the field of chemistry and chemical engineering, mainly including the following points: ① Strictly control the proportion of raw materials in the production process to avoid introducing stray ions, especially alkali metal or alkaline earth metal ions. ②: Try to reduce the content of glass phase and the conductivity of added glass phase to improve the process performance. ③ Strictly control the introduction of valence-changing metal ions such as iron and cobalt to avoid free ions and holes. ④ At the same time, the temperature and atmosphere in the production process should be strictly controlled to avoid electrons and holes generated by redox reaction and crystal defects caused by lattice transformation. This product has been widely used in high-temperature electric furnaces, induction furnaces, high-temperature motors, fire-resistant devices, motors, telecommunications equipment, high-temperature insulation equipment and so on. An important insulating material that can be cured into an insulating film or an insulating whole under certain conditions is generally composed of paint base, solvent or diluent and auxiliary materials. Requirements 1. Excellent insulation performance; 2. Good adhesion and high mechanical strength; 3. Low shrinkage stress; 4. The thermal resistance should meet the different requirements of the transformer; 5. Outdoor or special environment should meet its special requirements, such as radiation protection, corrosion protection and ultraviolet protection; 6. Good manufacturability, such as good operability, non-toxic or low toxicity, short drying time, etc. Classification of uses According to the scope of use, insulating paints can be divided into five categories: impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint and anti-corona paint. Impregnating paint Impregnating paint can be divided into solvent-based paint and solvent-free paint. It is mainly used for impregnating the coils of motors and electrical appliances and filling their gaps and micropores. After curing, a continuous and flat paint film can be formed on the surface of the impregnated object, making it stick into a hard whole. The basic requirements for impregnating varnish are: 1, low viscosity, good fluidity, high solid content, and easy to permeate and fill impregnating materials. 2, fast curing, good drying performance, strong adhesion and good thermal elasticity, and can withstand the centrifugal force when the motor rotates after curing. 3. Excellent electrical performance and chemical stability, moisture resistance, heat resistance and oil resistance. 4. Good compatibility with conductors and other materials. Enamelled wire paint Enamelled wire paint is mainly used for covering insulation of enameled wire core. Because the wire will be subjected to thermal, chemical and various mechanical forces in the process of winding coil and embedding wire, it is required that the enameled wire paint has good coating performance (that is, uniform coating), strong adhesion, smooth and soft surface, good wear resistance and elasticity, good electrical performance, heat resistance, dissolution resistance and no corrosion to conductors. Specifically divided into the following nine types. 1. The main component of acetal paint is polyvinyl formal, which is used to produce enameled wire of oil-filled transformer. 2. The main component of polyurethane paint is polyurethane, which is widely used to produce enameled wires of electronic requirements windings such as electronic transformers, electronic coils, relays, micromotors and high-frequency electrical instruments. 3. The solderable polyesterimide paint has the general properties of polyesterimide paint and can be directly welded at 475℃. 4. Polyester imine paint is the most widely used enameled wire paint, which has excellent thermal properties, usually higher than 180 grade. It can be used alone, and can also be used as a primer to compound with polyamide-imide or nylon paint to produce composite yarn. Widely used in freezers and air-conditioning compressors, explosion-proof motors, power tools, ballasts, dry-type transformers and other occasions with high insulation level. 5. polyester paint is mainly composed of polyester with good comprehensive performance. Used to produce enameled wires for washing machine motors, micromotors, instruments and telecommunications equipment, power tools and general motors. Heat-resistant polyester is modified by SEK, and a large number of primers and polyamideimide are used to produce refrigerant-resistant enameled wires. 6. Polyamide-imide is the most widely used enameled wire paint with high heat resistance (grade 220), which is mostly used as topcoat to produce composite wire to improve the comprehensive performance of enameled wire. Widely used in the production of sealed motors and refrigerant-resistant enameled wires. Some products can also be coated separately. In order to improve the performance of enameled wire, it can also be made into self-lubricating type and filler. It has great application in heavy-duty motor and automobile industry. 7. The thermal grade 240 polyester-imide paint has excellent performance, and the enameled wire is radiation-resistant. 8. Because of its lubricity, nylon paint is generally used for the surface layer of enameled wire. Other performances have also been improved. 9. Self-adhesive coatings mainly include polyamide, epoxy (phenoxy), aromatic polyamide and other different types of self-adhesive coatings according to the different components used. Generally do enameled wire topcoat. Used for bonding and molding deflection coils, transposed wires, voice coils and anisotropic coils. Covering paint Covering paint is used to coat the impregnated coils and insulating parts, and form an insulating protective layer with uniform thickness on its surface, so as to prevent the equipment insulation from mechanical damage and corrosion by atmospheric and chemical substances, and improve the surface insulation strength. Therefore, the covering paint is required to have the characteristics of fast drying, strong adhesion, hard paint film, high mechanical strength, moisture resistance, oil resistance and corrosion resistance. Covering paint is divided into alkyd paint, epoxy paint and silicone paint according to resin types. Compared with alkyd coatings, epoxy coatings have better moisture resistance, mildew resistance, internal dryness and adhesion, and the film hardness is high, which is widely used for surface coating of motor and electrical equipment parts in hot and humid environment. Silicone paint has high heat resistance and can be used as covering paint for class H electrical appliances. Finish paints can be divided into two types according to fillers: varnishes without fillers and pigments and enamels with fillers and pigments. Enamel made of the same resin has higher film hardness, better thermal conductivity, heat resistance and arc resistance than varnish, but other electrical properties are slightly worse, and it is mostly used to coat coils and metal surfaces, while varnish is mostly used to coat the inner surface of electrical appliances on the surface of insulated parts. There are two drying methods of finish: air drying and drying. The air-drying paint of the same resin is worse than the drying paint, and its storage is unstable. It is only suitable for large equipment and parts that are not suitable for baking. When covering paint is used, the viscosity and uniformity of paint, ventilation, baking temperature and environmental cleanliness should be strictly controlled to ensure the dryness and quality of paint film. Enamel must be fully stirred before mixing and use to eliminate precipitation, uneven viscosity or discoloration. Silicon steel sheet paint Silicon steel sheet paint is used to coat silicon steel sheet to reduce eddy current loss of iron core and enhance corrosion resistance. Silicon steel sheet needs to be dried at high temperature for a short time after painting. It is characterized by thin layer, strong adhesion, hardness, smoothness, uniform thickness, oil resistance, moisture resistance and good electrical performance. Corona discharge of anti-corona coating is a kind of discharge phenomenon that blue halo is produced by air ionization in local space with abrupt field strength (such as tip electrode) in extremely uneven electric field. Anti-corona paint is generally composed of insulating paint and non-metallic conductors (carbon black, graphite, etc.). ) powder, mainly used as anti-corona paint for high-voltage coils, such as the coil end with higher voltage in large-scale high-voltage motors. It is required in industry that the surface resistivity of anti-corona coating is stable, the adhesion is strong, the wear resistance is good, the drying speed is fast, and it is resistant to storage. Anti-corona paint can be coated on the surface of coil separately, on asbestos tape and glass tape, on the outer layer of winding wire, or on glass cloth to form main insulation at one time. Acetal lacquer Acetal lacquer is mainly composed of polyvinyl formal, which is used to produce enameled wires of oil-containing transformers. The main component of solderable polyesterimide paint is polyurethane. The enameled wire can be directly welded without removing the paint film. The welding temperature is generally 375 or below, and different thermal levels can be selected as required. Widely used in electronic transformers, electronic coils, relays, micromotors, high-frequency electrical appliances and other electronic requirements for winding enamelled wires. According to the insulation level, Insulating paints can be divided into seven categories: Y, A, E, B, F, H and C ... The details are as follows: Heat resistance grade: maximum allowable working temperature (℃) Y grade: 90℃ Insulation structure consisting of unimpregnated cotton yarn, silk, paper and other materials or their combination A grade: 105℃ Immersed or immersed in liquid dielectric (such as cotton yarn in transformer oil, At 20℃, the insulation structure composed of organic films is synthesized, and the organic enamel and other materials and their combinations are synthesized. Class B:130℃ f:155℃ h: 180℃. The insulation structure of Class C is composed of asbestos and other materials or their combinations:180℃. Other products 1. Strengthening the mechanical strength of electronic transformer Impregnating insulating paint can increase the mechanical strength of transformer and meet the requirements of vibration and impact during transportation and use. At the same time, it can also reduce the noise caused by electromagnetic force in use. 2. Improve the electrical insulation performance of electronic transformer. Impregnating electronic transformer with insulating paint can improve the electrical strength and insulation resistance of transformer insulation system, thus improving its electrical insulation performance and meeting the requirements of transformer electrical insulation performance. 3. Improve the thermal conductivity of electronic transformer. The electronic transformer is impregnated with insulating paint, and the gap between the core and the winding is filled with paint film, which can improve the overall thermal conductivity of the transformer and reduce the temperature rise of the transformer. 4. Improve the appearance of electronic transformer 5. Enhance the environmental adaptability of electronic transformers. Impregnating electronic transformer with insulating paint can enhance the performance of transformer insulation system in terms of moisture-proof, mildew-proof, corrosion-proof, salt spray resistance, ultraviolet protection and other harmful substances, thus enhancing the environmental adaptability of electronic transformer. Development trend of insulating paint In order to solve the problems of heat-resistant temperature and curing speed of H-class solvent-free impregnating insulating paint in China, Wang Xueqiu of East China University of Science and Technology and others made H-class solvent-free impregnating paint with modified diphenyl ether resin as the main raw material. This kind of coating not only has low viscosity, low curing temperature, short curing period and long storage period, but also is cheap, so it is an ideal new material. F-class quick-drying insulating paint prepared by Yu et al. with epoxy resin modified poly-cooling resin and proper amount of crosslinking agent has the characteristics of fast drying, short baking time, low baking temperature and good mechanical and electrical properties, and has been successfully applied to the manufacture and repair of hydro-generator sets and small and medium-sized motors. Shu Xinhua and others studied the production technology of insulating paint. On the basis of the original equipment and raw material ratio of terephthalic acid vinegar exchange process, a new process of atmospheric acetylation of terephthalic acid was adopted to produce 17 3 0 poly-vinegar insulating paint, and the product quality met the standard. Professor Yang of Nanjing University and others invented an H-class low-temperature direct welding polyurethane enameled wire paint, which has high solid content, good heat resistance and low-temperature direct welding performance.
JP-A-5-2 5 0 9 1 8 introduced a polyimide insulating paint, which has good heat resistance and wear resistance, and solved the problem that magnetic wires are easily damaged by wire film guides and molds during high-speed winding. On the basis of the original process, the invention adds a proper amount of blocked isocyanic acid vinegar components, and the blocked cyanic acid components will react with amino groups, residual carboxyl groups, acidic anhydrous substances and the like. To produce a dendritic long-chain alkyl structure. This structure is not only good in lubricity, but also good in solvent resistance, and it is not easy to pollute the guide rail during winding processing. JP-A-3-7 7 7 5 introduces a kind of polyurethane resin coating, which has excellent thermal shock resistance, wet heat resistance and good painting performance, and can be widely used in industrial fields. JP-A-i 1-3 5 8 8 4 discloses the insulation coating technology of polyurethane electrical appliances, which can be directly welded without peeling off the insulation coating. An American patent describes the composition of an insulating paint that can be directly welded at low temperature without affecting other properties. Its direct welding temperature and thermoplastic flow temperature are 23 0℃. The development of foreign insulating paint is obviously higher than that of domestic insulating paint. Foreign insulating paints not only have high heat resistance, but also have many coatings suitable for special purposes. Although China has done a lot of research in recent years, the quality and technical content of coatings need to be further improved.