Brominated flame retardants

Brominated flame retardants and environmental protection and human health
BFR current production is still one of the largest organic flame retardants, the estimated global total volume up to 250 ~ 300 kt / a, flame retardants in the proportion of 15% to 20%. Now the global electrical and electronic equipment used in fire retardant (FR), is estimated there are still 80 BFR.
BFR has been the production and use of more than 30 years, the current global production of a certain size of the BFR about 70 species, 10 of which the most important thing is bromine ether (DBDPO), Tetrabromobisphenol A (TBBPA) and six Central Bromine Dodecane (HBCD), the former two BFR of the total output of about 50%.
BFR flame-retardant high efficiency, broad application, heat resistance, and excellent hydrolytic stability, to meet a variety of polymer products processing technology and the use of fire retardant requirements, and adequate sources of raw materials, manufacturing processes mature, prices for users Bear. BFR the serious shortcomings in its fire-retardant polymer in the combustion of generating more smoke and toxic gases and corrosive gases, fire-retardant substrate was reduced by the lightfastness, some BFR easy exudation. Secondly, BFR general and antimony and use of such materials to the higher volume of smoke. In particular, since 1986, found that the fire-retardant polymer PBDPO and the pyrolysis and combustion products containing more than bromine Dibenzo Dioxins (PBDD) and multi-bromo dibenzofuran (PBDF), and in recent years That individual BFR (such as PBDPO) itself on the environment and human health of potential harm. Over the years, the European Union that is harmful to a variety of BFR assessment, and in accordance with the RoHS directive, has been provided in July 2006, in the new EU listing of the electrical and electronic products banned five bromine two stupid ether (PeBDPO) and eight Bromine two stupid ether (OBDPO). Although not yet found DBDPO the apparent toxicity. Other BFR assessment has not yet reached firm conclusions, but the current attitude of the people of BFR very carefully, of course, to BFR cast a shadow over the prospects. However, because BFR in the field of fire-retardant important historical status and, in many applications, BFR is still difficult to find suitable substitutes, BFR in these areas is still no alternative choice. Find BFR, especially PBDPO alternatives to the progressive realization of the non-halogenated fire retardant and environmental protection, is a clear trend.
In view of the above, with special paper in the form of questions and answers on the BFR and environmental protection and human health, the issues of concern to people close elaborate.
Q BFR in the use of consumer goods, products can escape from » People can absorb » Whether or not harmful to the health of consumers »
A This is a BFR on whether the health of consumers and potentially dangerous problem. In theory, the use of BFR of consumer goods, of course, consumers may contact BFR, but this possibility minimal. France recently with three BFR (TBBPAV, HBCD or DBDPO) of a range of products have been studied, are not detected from them escaped BFR. However, some researchers did find, containing TBBPA shell in the computer monitor can be tested under the conditions of escape TBBPA, but its volume can almost be ignored. If the display case was non-TBBPA, but its board of TBBPA, then under the same conditions, found no TBBPA escaped.
Generally speaking, fire-retardant products released by the FR and the possibility of escape is usually very small and can not be a hazard to consumers. As for the reaction-FR, their products are no longer the original compound, but generated some other substances, or combination of fire retardant on the substrate (polymer) in the main chain or a side chain, which is not From the products moved to the environment. There is no FR on the human body and produce harmful effects of organisms, found no more because of human exposure to the environment in the FR of the serious consequences arising from the case. According to EU regulations, the vast majority of FR can not be classified as hazardous (or toxic) material.
Q BFR in the production, use, disposal, recycling and the fire can generate PBDD and PBDF?
A BFR in 75, is currently only found PBDPO PBDD and PBDF precursors, and because PBDPO PBDF to generate PBDD and under certain conditions can occur with the formation of its conditions. General in 500 ~ 600 ℃ under anaerobic or hypoxia hot crack, and relatively easy to form PBDD PBDF, and in the following 300 ℃, and PBDF PBDD generated little volume. However, PBDPO and Sb2O3 and use, fire-retardant materials generated at the crack of PBDD and PBDF volume increased. But that is split by the laboratory of the results devices, which split the small thermal conditions and industrial installations burning installations and the scene of the fire conditions are different. City solid waste incineration can also have a small amount of dioxin compounds. BFR will contain plastic and urban solid waste to incineration, and PBDF PBDD did not increase the generation capacity. DBDPO in the processing of plastic workshop, the dioxin concentrations below the relevant German regulations of two orders of magnitude, the study shows that with DBDPO even after several plastic recycling processing, material detected in the volume of PBDD and PBDF Also very small, can still command by the German dioxin (10-9 pole).
FR asked to stay in the environment? »
FOR FR are fairly stable, because they must bear 200 ~ 350 ℃ plastic processing temperature, but also in plastic to maintain throughout the life of fire-retardant, the FR is so unstable can not be used for fire-retardant polymer. From this perspective, some FR stranded in the environment is completely impossible, but stranded in the environment does not mean that they will harm human health and harmful to the environment, depending on volume and was stranded in the nature of stranded FR. In addition, not all of the FR will be stranded in the environment. For example, DBDPO not degradation, but TBBPA and HBCD in the residue and soil degradation.
Asked whether there PBDPO environment and other BFR? Whether they are harmful to the environment and human health »
FOR the environment in some locations, it found PBDPO, but its composition is mainly PeBDPO and other low-bromo two stupid ether. DBDPO OBDPO moved to the remote and less likely. PBDPO found in the areas of sampling, per gram sample of the average levels in the DBDPO only 5 X10-9g, such a concentration on the environment and human health will not have an impact.
DBDPO in the production and use of the premises, the dust is also found in the DBDPO, but even the highest concentration reported, only acceptable toxicity limit the concentration of several hundred thousandth, which will not endanger human health.
Now, the Ministry of Industry and the European Union and the United DBDPO users, the ongoing research to better control and reduce DBDPO escaped to the environment. At the same time is also preparing to launch a similar voluntary study to control and reduce other BFR emissions to the environment.
In the environment has been detected in the BFR also TBBPA and HBCD, their existence depends on the location and quantity of its nature and related products manufacturing, processing and use of locations. Now they are studying the environment and human health effects.
Q BFR is a permanent organic pollutants (POP)? »
A BFR is not POP, and the United Nations has not been included in the POP list. According to the United Nations definition, POP must meet the following four conditions: Persistent (P), bio-accumulation (B), toxicity (T) and long-distance migration (LRT). At present the market with the BFR one of the four have not only have been banned PeBDPO possible that the POP.
Similarly, BFR is not a persistent accumulation of toxic substances. However, BFR is certainly stable, because they have to play in the long-term fire-retardant features. For example, within the walls of fire-retardant insulation board can be used for more than 30 years.
Q DBDPO in the degradation of the environment? PeBDPO »
FOR because PeBDPO has been disabled, so people will worry about DBDPO in the environment degradation for PeBDPO. Netherlands to a recent study pointed out that in the residues on the surface, PeBDPO and other low-bromo stupid ether in the lower and higher concentrations of DBDPO. This shows that, DBDPO degradation is unlikely to PeBDPO and HBDPO (6 bromine two stupid ether). The study also shows that, DBDPO without the possibility of accumulation, or very low. There are a few more independent on DBDPO degradation of the study, provided some valuable DBDPO light of the information. However, in order to fully understand the situation in this respect, the need for further experiments.
Asked what the body found BFR?
Answer in fish, meat, dairy and other food items were found in PBDPO, but its concentration is very low, even though the highest concentration detected from the toxicological point of view, only acceptable limit the concentration of several parts per million .
In the human body also detected a PBDPO and other BFR, but they are far below the concentration can affect human health concentration.
Human milk only found PeBDPO, but its content is only toxic effects can cause the concentration of several hundred thousandth. Found in human milk in the PeBDPO, its content in 50 percent to 70 percent of the 2,2 ', 4,4' - four bromine two stupid ether, followed by 2,2 ', 4,4'5 - five of bromine Stupid ether, both of these compounds are a major part of PeBDPO.
PeBDPO human milk in the content in the 1990s has increased in 1997 reached the highest value, but is now a relatively big drop, declining 30 percent every two years, because in recent years the use of the European PeBDPO reduce its release to the environment The volume of the corresponding lower.
Because DBDPO not easy migration in the environment, it is difficult or not be absorbed by animals, but a recent Swedish study found that the eggs in the presence of trace DBDPO, which has aroused the close attention of relevant departments, and also to conduct a In-depth study.
In addition, fish and birds have been found in the body HBCD, environmental samples HBCD in the concentration is usually very low, generally (10-9 ~ 10-12) g / g. The EU is this assessment.
Be made in the body of any synthetic chemicals, not necessarily the same in the life of the health hazards. Experts believe that in the body appears a certain chemicals are hazardous to health does not necessarily signal, and depends on such chemicals in the body of concentration.
BFR will be asked whether the accumulation of organic tissue »
A majority of BFR is not the biological accumulation, in other words, they will not stay in the body or the accumulation. As BFR the molecular weight, dissolved in the water very low, so they would not normally be absorbed organisms. Only a very small number of industrial BFR (PeBDPO, PBB (PBBs)) may have on the accumulation of. According to the World Health Organization and the European Union on the FR danger of the assessment results, DBDPO accumulation of non-biological.
Q BFR will affect people or animals, endocrine system? »
A BFR will not affect the endocrine system. PeBDPO, HBCD and TBBPA will rat thyroid hormones in the blood changes, but have not yet found a rat poison, and there will be no such hormonal changes in the human body. In addition, the concentration of people to contact the BFR far from sufficient to produce harmful effects.
Q BFR toxic to the nervous system? »
FOR even animals exposed to high concentrations of DBDPO, HBCD and TBBPA in the atmosphere longer period of time, have not found that these animals BFR on the impact of the nervous system. Tests for pregnant female animals, also found no BFR on the fetal nervous system effects.
Asked the EU RoHS directive disabled DBDPO? »
FOR early 2003 the European Union enacted RoHS directive, the disabled and PBDPO is PeBDPO OBDPO, and DBDPO at the time of DBDPO is awaiting the final outcome of harm assessment, the assessment has been completed and found no DBDPO to human health and ecological and environmental hazards . At the same time, the European Union on DBDPO advice to the authorities concerned have been completed. April 19, 2005, the EU member states have a vote, the majority of EU member states will not support DBDPO attributable to disable the scope of the RoHS directive.