Detailed data collection of conductive coatings

Anti-electromagnetic interference forbidden coating. Commonly known as: conductive paint. Conductive coating is a kind of coating with good conductivity, and composite particles containing copper and silver are used as conductive particles.

Chinese name: Anti-electromagnetic interference forbidden paint commonly known as: conductive paint category: paint properties: introduction, overview, functions, types, working principles, such as copper conductive paint, pure silver conductive paint, nickel conductive paint, introduction overview conductive paint is a special functional paint developed rapidly with modern science and technology, with a development history of about half a century. 1948, the United States announced the patent of making conductive adhesive with silver and epoxy resin, which was the earliest disclosed conductive coating. China also began to study and apply conductive coatings in 1950s. In recent decades, conductive coatings have been used in many military and civilian industrial fields such as electronics, electrical appliances, aviation, chemical industry, printing and so on. Accordingly, the theoretical research of conductive coatings has also developed rapidly, which has promoted the maturity and perfection of application technology. Functional conductive coating is a kind of coating that can be sprayed by adding conductive metal powder to a specific resin raw material. After drying, it can form a paint film and play a conductive role, thus prohibiting electromagnetic interference. Prohibition refers to the metal isolation between two spatial areas to control the induction and radiation of electric field, magnetic field and electromagnetic wave from one area to the other. Specifically, the interference source of components, circuits, components, cables or the whole system is surrounded by the forbidden body to prevent the interference electromagnetic field from spreading outward; Enclose the receiving circuit, equipment or system with a forbidden body to prevent them from being affected by external electromagnetic fields. According to the application characteristics, the types are classified: 1. Coatings used as electrical conductors, such as hybrid integrated circuits, printed circuit boards, keyboard switches, heating coatings for winter heating and automobile glass antifreeze, and antifouling coatings for ships. 2. Radiation protection coatings, such as radio waves and electromagnetic waves. 3. Antistatic coating 4. Others such as electrochromic coatings and photoconductive coatings. For the conductivity of conductive coatings, there are usually three representations: volume resistivity or conductivity; Surface resistivity; Electrostatic attenuation rate. According to the classification of applied materials, intrinsic conductive coatings refer to conductive coatings made of intrinsic conductive polymers as film-forming substances. The preparation methods of conductive polymers for conductive coatings mostly focus on the direct use of conductive polymers as film-forming resins, the use of conductive polymers mixed with other resins, and the use of conductive polymer materials as conductive fillers, among which polyaniline, polypyrrole, polythiophene and polyquinoline are the most typical representatives and are an active research field. Intrinsic conductive coatings are mainly used in anti-corrosion and antistatic coatings, absorbing coatings, electromagnetic shielding coatings and so on. A variety of polyaniline antistatic and anticorrosive coatings have been developed in China. Doped conductive coating refers to adding conductive substances on the basis of polymer, and using the conductive effect of conductive substances, the conductivity of the coating can reach more than10-12s/m. It not only has conductive function, but also has many excellent characteristics of polymer. It can adjust the electrical and mechanical properties of the coating in a wide range according to the needs of use, and has low cost and simplicity, so it is widely used. Doped conductive coating consists of polymer, conductive filler, solvent and additive. Commonly used conductive fillers include metal-based fillers, carbon-based fillers, metal oxide-based fillers, composite fillers and new nano-conductive fillers. (1) Carbon-based conductive coating Carbon-based conductive coating is a kind of functional coating with large dosage, which has the advantages of low cost, light weight, high structure, innocuity and harmlessness. Conductive fillers used as carbon-based conductive coatings mainly include graphite, graphite fiber, carbon fiber, high-temperature calcined petroleum coke, various carbon blacks and silicon carbide. In particular, conductive polymers filled with carbon black have been widely used, because conductive carbon black has the advantages of low price, low density, difficult sedimentation and strong corrosion resistance, but its conductivity is relatively poor; At the same time, because the surface contains a lot of polar groups, it is difficult to disperse and easy to flocculate. One of the simplest and most effective solutions is to add dispersant to reduce the attraction and cohesion between carbon black particles and make them evenly and stably dispersed in the matrix. Carbon-based conductive coatings are usually composed of conductive fillers, matrix resins, additives and solvents. After mechanical mixing, it is coated on the surface of non-conductive substrate to form a special cured film, thus producing conductive effect. (2) Graphite Conductive Coating Graphite is a highly conductive layered material, which can be used as a conductive filler and compounded with conductive polymers to prepare polymer-based composites with excellent conductivity. Graphite coating has good conductivity, low price and simple operation process, which plays an irreplaceable role in the internal and external coating of color tube glass shell. In order to make the coating have good conductivity, high-purity ultrafine graphite must be prepared by deep processing to meet the needs. With the development of nanotechnology, it is more and more popular to prepare conductive polymer materials by combining graphite nanomaterials with matrix. As a new conductive filler, expanded graphite has the advantages of good conductivity, low friction loss and little pollution. Moreover, the addition of expanded graphite can greatly improve the conductivity of polymer materials and reduce the filtration value of conductive penetration, so it has important application value in antistatic coatings and conductive polymer composites. (3) Metal Conductive Coatings The conductivity of metal conductive coatings depends on the type and quantity of metal fillers, the type and quantity of metal fibers and metal powders, and the shape of fillers. Metal fillers mainly include silver powder, nickel powder and copper powder, among which silver powder has good chemical stability, excellent corrosion resistance and high conductivity, and is an early conductive filler developed and applied. However, due to the high price of silver powder, many sets of silver powder are used in the military field, but less for civilian use. Nickel powder is widely used because of its good chemical stability, effective anti-electromagnetic interference and moderate price. Copper powder is cheap and its conductivity is similar to that of silver, but its disadvantage is that copper is easy to be oxidized and its conductivity is unstable. But after special surface treatment, a stable copper-based conductive coating can be obtained. With the improvement of oxidation resistance technology of copper powder, the research of copper-based conductive coatings will be further valued. (4) Nanotubes with conductive coating have large aspect ratio and excellent electrical properties. Adding it into polymer as reinforcing phase can greatly improve the mechanical properties and photoelectric properties of polymer, so it can be used to prepare functional carbon nanotubes/polymer conductive coatings, which can be used in many fields. Nanotube conductive materials and film-forming materials penetrate each other with almost the same particle size, and there is no obvious interface between them, so the anticorrosion performance of nanotube conductive coatings is better than that of general anticorrosive coatings. (5) Because of its excellent electrical properties and light color, metal oxide can make up for the shortcomings of poor corrosion resistance of metal conductive pigments and poor decoration of carbon-based conductive pigments. Commonly used composite fillers include glass beads, copper powder, mica powder coated with silver powder and carbon black coated with nickel powder. Metal oxide conductive pigments mainly include doped tin oxide, zinc oxide, antimony dioxide and so on. Among them, SnO2 _ 2, as the representative, has attracted much attention because of its low density, good stability in air, light color and transparent coating. Working Principle Conductive coatings can make completely insulated nonmetallic or non-conductive surfaces have the characteristics of absorbing, conducting and attenuating electromagnetic waves like metals by spraying and brushing, thus playing the role of prohibiting electromagnetic wave interference. The appearance of conductive coatings effectively solves the problem of electrical connection of nonmetallic surfaces. Conductive coatings are anti-electromagnetic interference coatings made of electroplated silver particles. It is one-component, labor-saving, time-saving and convenient, with good adhesion, smoothness, strong cohesion and no loose particles. It can be used as a coating material for the inner wall of the shell based on metal and composite materials, such as mobile phones, calculators and precision instruments. After drying and curing, the paint layer has stable performance, fine and smooth surface on the workpiece, and has excellent conductivity of pure silver conductive paint. Fine conductive particles ensure the safety of electronic components. In order to ensure the adhesion between the paint and the base surface, under normal circumstances, conductive paint is only recommended to be used on the surface of non-metallic materials such as PC and ABS. If used on unusual surfaces, it may need to be used with primer. For example, copper conductive paint is widely used in the following specific types of products: "silver conductive paint" with silver metal powder added; Adding copper powder is called copper conductive paint "; Adding nickel powder is nickel conductive paint "; Copper conductive paint is the most widely used because it is much cheaper than silver conductive paint. Compared with nickel, the conductivity is much better. Specific indicators can be referred to as follows: Parameter indicator Copper conductive paint product number: 602 Packing specification:1/5120kg/barrel Product description color: gold or silver specific gravity:1.150.05 (ASTM d1475 % Theoretical coating ratio: 8-65438+. cm2 (film thickness not less than 20 microns) Applied conductivity parameter: 1 ohm /20 micron film thickness/distance 10cm. Recommended film thickness: 20-25 microns (ASTM D4 138-94). The drying time is 65438 05 minutes, and the drying time is 65 5℃/34. 6 months /25℃ (intact) pure silver conductive paint Basic introduction Product number: 828 Packing specification:1/5/120kg/barrel Product description: coating characteristic color: silvery white specific gravity:1.30.05 (ASTM d140. Dilution release agent: ethanol/tap water (boiling oil). The boiling oil ratio is 1: 0.5 (weight ratio). The drying time is15min, and the drying time is 65 5℃/3010min. Basic information 6 months /25℃ (intact) Nickel conductive paint ProductNo.: 606 Packing specification:1/5/120kg/barrel Product description: color: dark gray, black gray or silver gray, specific gravity:1.40.05 (ASTM d/kloc-0 % theoretical coverage: 6-8m2/kg (film thickness =25 microns) Technical parameters 25 microns film thickness/distance 10cm Recommended film thickness: 25-30 microns (ASTM D4 138-94) When measuring the test conditions, the film to be sprayed must be completely cooled and dried. The multimeter with digital display should be used for measurement (in general, the gear of the multimeter should be adjusted to