The relevant knowledge of PCB

1. The raw materials

 

At the beginning of the 20th century to the late 1940 s, is the infancy of the PCB substrate material industry development. It mainly displays in: the development characteristic of this period with the resin substrate material, reinforced material and insulating substrate, get a preliminary exploration on technology. These are the most typical substrate material for printed circuit board, copper clad with the advent of development, create the necessary conditions. On the other hand, in order to foil etching method (subtraction method) manufacturing circuit PCB manufacturing technology for the mainstream, the initial establishment and development. It is copper clad on the determination of the structure, characteristic, has played a decisive role.

 

2. polychlorinated biphenyl

 

PCB polychlorinated biphenyls (PCBS) in 1929 until the late 70 s north American business using a synthetic organic compounds, while Canada not the chemical processing production, but also has been widely used in electrical equipment insulation, heat exchangers, water systems and other special applications.

 

After decades after people realize the polychlorinated biphenyls (PCBS) on the global environment pollution, which is a mixture of various chlorinated biphenyl, has a great harm to human body. The Canadian government has taken measures to try to eliminate the PCB, but happened in Canada in 1977 illegal import, processing and sales of the phenomenon of PCB, and the PCB in 1985 illegal released into the natural environment, and the Canadian constitution allows owners continue to use the PCB equipment until the life period of equipment. Canada since 1988, the provincial government began for PCB storage, transportation and destruction of the rules.

 

PCB is not easy to break down in a natural environment, but also spread very far, PCB in production and processing, use, transport and waste disposal process into the air, soil and river and sea, small Marine organisms and fish breathe to PCB, and they have become great Marine food, as a result, PCB went into the body of the all sea life, including mammals of Marine biology. The accumulation of PCB in the Marine organism far beyond it in the water content, almost is the number of thousands of times.

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