Halogens include five elements: Fluorine, Chlorine, Bromine, Iodine and Astatine. Astatine is a radioactive element, and halogens are commonly referred to as fluorine, chlorine, bromine, and iodine. Halogen-free control mainly involves Chlorine and Bromine.
Halogen compounds have received extensive attention due to the following hazards:
1. Some halogen compounds are harmful to the environment and human body: such as halogen-containing persistent organic pollutants POP;
2. Organic solvents containing halogens are ozone layer destroying Substances (ODS)
3. When the halogen-containing plastic encounters high temperature, it will release hydrogen halide (HCl, HBr, etc.), which will form acid fog when it meets water vapor in the air;
4. When halogen-containing plastics are burned, dioxins are produced, which are highly accumulated and highly durable carcinogens;
5. When halogenated plastics burn, a large amount of smoke will be generated, resulting in reduced visibility and affecting the identification of escape paths.
At present, halogen-containing plastics, especially those containing chlorine and bromine, are widely used in the electronic and electrical industry. Halogens in plastics include PVC, plasticizers, flame retardants, etc., while containing other forms of halogens, such as: color powder, pigment and other organic halogens. The most common Flame Retardants are Chlorinated Flame Retardants (CFRs) and Brominated Flame Retardants (BFRs). There are hundreds of types of BFRs, and the price is low, the flame retardant effect is good, and the cost performance is very high, so it has been widely used and recognized. Common flame retardants include organic flame retardants and inorganic flame retardants, organic flame retardants include CFRs, BFRs, phosphorus flame retardants, etc. The inorganic flame retardants include: boron flame retardants, aluminum hydroxide, magnesium hydroxide, red phosphorus, ammonium polyphosphate, antimony oxide and molybdenum compounds, etc., their flame retardancy is low, the addition amount is large, far less than CFRs and BFRs widely used. If the application of BFRs is now completely banned, it is difficult to find a better alternative than BFRs in a short time. At the same time, halogen-containing plastics are facing great difficulties in recycling and disposal, so more and more customers are paying attention to halogen-free.
Standard and regulatory requirements
Regarding the halogen-free requirements, IEC61249-2-21:2003 has provisions for the printed circuit board, the specific requirements are: Bromine < 0.09% (900 ppm), chlorine < 0.09%(900 ppm), the sum of halogens < 1500ppm.
Detection methods are
IPC-TM-650 2.3.28.2; BS EN 14582:2007 standard;
IEC 61249:2003 Part 2.21 (IEC 61189:2006-3);
JY/T 020:1996 General Principles of ion chromatography;
GB/ T9872:1998 Determination of halogens in rubber;
ASTM D 4327:2003 Determination of Common anions in water, etc.
Halogen-free is a trend, although there is currently no uniform regulatory requirements, in the future will be issued relevant. Therefore, as a company, we should reduce the use of halogenated materials and find alternative materials.
