Water-based Environmentally Friendly Electromagnetic Shielding Paint And Its Application

With the fast development of electron technology, a series of problems of electromagnetic interference,reveal information,electromagnetic radiation pollution caused by electromagnetic radiation become more and more serious. Consequently we cry for protecting against electromagnetic irradiation systemly. Electromagnetic shielding technology also appears its importance gradually.In the dissertation, the harm of electromagnetic radiation and importance of electromagnetic shielding, the study and the development of the electromagnetic shielding materials, the necessity of waterborne were reviewed. On the base, the research of the waterborne electromagnetic shielding coatings was discussed in order to probe into its engineering application fields and prospects.The results of the study for the electromagnetic shielding coatings showed: the content and dispersion of the fillers, resin, coupling-agent, and solidify technics, thickness were important in the functions.The best batch formula of the study is showed as following: the resin we choosed is the mixture of acrylic acid emulsion and polyurethane emulsion, the proportion is 15:1; The content of the fillers is 20%-30%; m_基/m_颜of T-2 the silver-plated copper powder electro conductive coating is at the range of 0.65-0.7, m_基/m_颜of T-4 is 0.8-0.85; The best dosage of coupling-agent is 1.6%-2%; We choosed HEUR as thickening agent, which mixed HASE to use, the content of HEUR is l%-2%, the content of HASE is 5 percent of HEUR; The range of thickness we choosed is 16-20μm; The content of water is at the range 30-40%; The best solidify technics is solidifing 10min at 60℃.The performances of coatings we studied can accord with correlative standard. In conclusion, the number of contacting particles and the shortest distance among particles are the key factors, which decide the completeness and closely knit degree of the framework.The coatings' performance test results show that: the coating's appearance is smooth and sleekness, its adhesive power reaches to one class, and it is wearable. The coating's stability of the electro conductivity and anti-sedimentation are good after six months storage at normal temperature. The waterborne coatings' electromagnetic shielding efficiency was tested by National Center of Testing Technology, Shanghai , the results showed that the electromagnetic shielding efficiency of T-2 silver-plated copper powder electromagnetic shielding coating is at the range of 62.2 to 70.5dB, while the electromagnetic shielding efficiency of T-4 silver-plated copper powder electromagnetic shielding coating is at the range of 63.2 to 78.1dB, when the frequency from 0.01MHz to 3000MHz.The waterborne coatings are able to bear alkali,acid,wate,weather,high-temperature , and their anti-oxidation is good, the electromagnetic shielding efficiency at wide frequency is fine. The waterborne electromagnetic shielding coatings have excellent electric conductivity and environment-friendly, it is a high-efficiency, cheap, convenient technology tool, so it will be widely applied in the future.