1.1 what is halogen-free printed circuit board
According to jpca-es-01-2003 standard: the copper clad laminate with chlorine (C1) and bromine (BR) content less than 0.09% wt (weight ratio) is defined as halogen-free copper clad laminate. (at the same time, total CI + br ≤ 0.15% [1500ppm])
1.2 why should brine be prohibited
Halogen refers to the halogen group elements in the periodic table of chemical elements, including fluorine (f), chlorine (CL), bromine (BR) and iodine (1). At present, flame retardant materials, such as FR4 and CEM-3, are mostly brominated epoxy resin. In brominated epoxy resin, tetrabromobisphenol A, polybrominated biphenyl, polymerized polybrominated diphenyl ether and polybrominated diphenyl ether are the main blocking fuel for copper clad laminates, which are low cost and compatible with epoxy resin. However, studies by relevant institutions have shown that halogen containing flame retardant materials (polybrominated biphenyl PBB: polybrominated diphenyl ether PBDE) will emit dioxin dioxin (TCDD) and benzfuran (benzfuran) when they are burned on fire. They have a large amount of smoke, bad smell, high toxic gases, carcinogenic, and can not be discharged after ingestion, which is not environmentally friendly and affects human health. Therefore, the EU initiated a ban on PBB and PBDE as flame retardants in electronic information products. According to the same document issued by the Ministry of information industry of China, the electronic information products put into the market shall not contain lead, mercury, hexavalent chromium, polybrominated biphenyls or polybrominated diphenyl ether.
Six substances, such as PBB and PBDE, are prohibited by EU law. It is understood that PBB and PBDE are basically not used in the copper clad laminate industry. Bromine flame retardant materials other than PBB and PBDE are mostly used, such as tetrabromobisphenol A, dibromophenol, etc., whose chemical formula is cishizobr4. This kind of copper clad laminate containing bromine as flame retardant is not regulated by any laws and regulations, but this kind of copper clad laminate containing bromine will release a large amount of toxic gas (brominated type) during combustion or electrical fire. When PCB is used for hot air leveling and component welding, the board is exposed to high temperature; 200) will also release a small amount of hydrogen bromide; whether it will also produce dioxins is still under evaluation. Therefore, FR4 board containing tetrabromobisphenol A flame retardant is not prohibited by law and can be used, but it can not be called halogen-free board.