Brominated and chlorinated flame retardants

Many brominated flame retardants (BFRs) are persistent and bioaccumulative chemicals that are now present throughout the environment. Polybrominated diphenyl ethers (PBDEs) are one of the most common groups of BFRs and have been used to fireproof a wide variety of materials, including textiles. Some PBDEs are capable of interfering with the hormone systems involved in growth and sexual development. Under EU law, the use of some types 

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There are a relatively small number of producers of halogenated flame retardants, especially for brominated flame retardants, where three producers account for greater than 80% of world production. Table 10 gives estimates of the volumes of brominated and chlorinated flame retardants used worldwide. Volumes of flame retardants consumed in Japan have been summarized (61). Prices of halogenated flame retardants vary from less than 2.00/kg to as high as 13.00/kg. Cost to the user depends on the level of use of the specific flame retardant and other factors such as the use of stabilizers. 

Tomy, G., Ismail, N., Rleskach, K., Marvin, C., ittle, M., Keir, M., Helm, R (2007) Temporal trends of brominated and chlorinated flame retardants in lake trout (Salvelinus namaycush) from Ontario (1979-2004). In Rroceedings of the 4th International Workshop on Brominated Flame Retardants, Amsterdam, The Netherlands, 24-27 April 2007 (unpaginated). 

Ismail, N., Gewurtz, S. B., et al. (2009) Brominated and chlorinated flame retardants in Lake Ontario, Canada, lake trout (Salvelinus namaycush) between 1979 and 2004 and possible influences of food-web changes. Environmental Toxicology and Chemistry, 28(5) 910-920. 

DiGangi J, Blum A, Bergman A, de Wit CA, Lucas, D, Mortimer D, Schecter A, Scheringer M, Shaw SD, Webster TF. (2010, Dec). San Antonio statement on Brominated and Chlorinated flame retardants. Environ Health Perspect., 118(12), A516-A518. 

Brominated and chlorinated flame retardants are sold throughout the world by the major producers or their affiliates. The phosphorus flame retardants are more likely to be sold through regional producers particularly in the Asia/Pacific region. Antimony oxide producers, other than Anzon, are regional, although most of the crude material is sourced from the same place, namely, China. ATH is produced by the major aluminum companies, but is upgraded and treated by other processors who sell to the plastics industry. 

There is a need for good alternatives for brominated flame retardants. Apart from other disadvantages, the heavy metal antimony is necessary for the production of brominated (or chlorinated) flame retardants. Antimony oxides, Sb205 (used in reactive flame retardants) and Sb203, are used as synergists to increase the efficiency of bromine and chlorine. Bromine and chlorine (together), and antimony oxides are used at a ratio of 1 3 [7]. 

Flame letaidancy can be impaited to plastics by incorporating elements such as bromine, chlorine, antimony, tin, molybdenum, phosphoms, aluminum, and magnesium, either duriag the manufacture or when the plastics are compounded iato some useful product. Phosphoms, bromine, and chlorine are usually iacorporated as some organic compound. The other inorganic flame retardants are discussed hereia. 

Bromine as a Reactive Flame Retardant. Bromine and chlorine are the starting materials for all of the commercial compounds described. Bromine is also used in a somewhat different way to impart flame retardancy. That is, it is used to brominate the resin in interest directly. This is practiced commercially in the case of unsaturated polyesters (59). 

The use of aromatic brominated compounds as flame retardants has been a potential source of environmental contamination. Incomplete incineration of these compounds and wastes (plastics, textiles, oils etc...) containing brominated flame retardants caused formation of brominated/chlorinated dibenzodioxines (PBDDs/ PCDDs) and dibenzofurans (PCDFs/PBDFs) (refs. 1 - 4). 

Brominated and chlorinated organic flame-retardants can be analysed using either GC-MS or LC-MS. High resolution systems are required to identify the specific isomers. Quantification by bromine or chlorine content is normally achieved using XRF against standards in the same matrix. 

Additive flame retardants, brominated and chlorinated, 11 461—470 Additive mixing, in color photography, 79 240-241... 

Flame retardants, 11 447-454, 459-479. See also Fire retardant entries Halogenated flame retardants Phosphorus flame retardants antimony compounds in, 3 54 brominated and chlorinated additive, 11 461-470... 

Beryllium and compounds Other chlorinated flame retardants Other brominated flame retardants... 

The order of effectiveness of halogens is I > Br > Cl > F [20]. Iodine-containing organic compounds are too thermally unstable to be melt compounded with polystyrene, and organoflorine comounds are too thermally stable to be effective as flame retardants. This leaves bromine- and chlorine-containing compounds as the most effective flame retardants. 

In the case of flame retardant silicone elastomer, many ingredients such as silica, platinum, and other flame retardant agents are incorporated into the base siloxane polymer. But there is no need to use the halogenated flame retardant agent, for example, bromine or chlorine compounds. This difference is an advantage of silicones compared with other synthetic polymers in terms of health and safety. 

Bromine and chlorine are two reactive halogens that have worked well for flame retardant purposes. Organo-fluorine compounds have not been as effective as flame retardant additives because the carbon-fluorine bond energy is so high that other events dominate at temperatures where halogenated flame retardants operate. ... 

Chlorinated flame retardants are much less effective than the equivalent brominated compounds, and are declining in use. The level of chlorination necessary for sufficient flame retardancy often has a detrimental effect on the desired properties of the polymer. Chlorinated paraffins (aliphatics) are used in plastics, textiles, and coatings. Chlorinated aromatics are not used as FRs. 

CHEMICAL PROPERTIES noncombustible solid reacts vigorously with acids and hot water hydrolyzes in hot acid solution elevated temperatures cause a highly exothermic reaction with water dehydrates liquid or solid amides to nitriles liberates ammonia at elevated temperatures and forms imidodisulfonates forms addition products with formaldehyde and aldehydes readily oxidized by bromine and chlorine has flame retardant properties because heat decomposition produces non-inflammable gases decomposes at 200°C (392°F) at 760 mmHg FP (N/A) LFL/UFL(N/A) AT (N/A). 

Intrinsically non-flammable polymers are few, but phenolic resins have a good reputation both in Are and smoke performance, which has resulted in their becoming increasingly favoured for reinforced plastics structures, for example, underground transport, where such concerns are greatest. Polyether ether ketone (PEEK) is also a low fire and smoke polymer. Unsaturated polyesters, vinyl esters and epoxy resins bum readily, but modified versions are available with improved behaviour. For example, both bromine and chlorine are used extensively in the form of chlorendic (HET) acid, tetrachlorophthalic anhydride (TCPA) and tetrabromo-phthalic anhydride (TBPA) which can be reacted into the polyester in small quantities and can act as permanent (non-migrating) flame retardants. 

The flame-retardant properties of bromine and chlorine compounds are well known. Their effectiveness in a given situation appears to depend very much on the right choice of flame-retardant compound. Since these halogens are believed to exert their effect mainly in the form of hydrogen halide molecules, a great deal depends on the ease with which HCl or HBr is produced from the flame-retardant molecule under pyrolysis conditions. 

Unitex Chemical offers Uniplex FR 44-57, a brominated and chlorinated dioctyl phthalate that acts as a low temperature plasticiser as well as a flame retardant. 

Besides bromine and chlorine, there are a small number of fluorinated ffame retardants. Potassium perffuorobutane sulfonate has been promoted by 3M as a replacement for the brominated flame retardants traditionally used in transparent polycarbonate. It had previously been marketed by Bayer for the same purpose, but the patent had expired. 

Dover Chemical Corp. is a subsidiary of ICC Industries Inc. headquartered in New York City. Dover s products are extremely diverse the chemicals made include brominated and bromo-chlorinated flame retardants, benzophenone and hindered amine light stabilisers, phosphite stabilisers, surfactants, lubricants, metallic stearates, and alkyl phenols. It is also a leading manufacturer of chlorinated hydrocarbon waxes, and there are several chemical products unrelated to plastics. 

Phosphorus containing flame retardants are used as phosphates, phosphonates, phosphines and phosphinic oxides. Halogen-containing phosphate esters such as bromine and chlorine in the form of tris (halogen alkyl) phosphates are popular [33]. The effects of phosphorus and brominated additives on flexible PU foam were compared [179]. Melamine has broad utility as a flame retardant additive in flexible PU foams [180]. 

Brominated and chlorinated FRs can also react synergistically with each other in plastics compounds. Occidental s proprietary chlorinated FR can be used with decabromodiphenyl oxide (DBDPO) to flame retard ABS, and mixtures of chlorinated and brominated FRs can be used in polyolefins. Work on ABS formulations suggests that the highest oxygen index is obtained at a 1 1 chlorine/bromine mixture, which also gives UL 94 V-0 rating at both 3.2mm and 1.6 mm,... 

A halogenated flame-retardant plasticizer is produced by Uniplex, containing bromine and chlorine. It improves low-temperature brittleness and provides lower smoke than conventional brominated phthalate diesters, for use primarily in wire and cable applications of flexible PVC, EPDM, and thermoplastic olefins. 

GE Advanced Materials was formed by the merger of the Plastics, Silicons and Quartz Divisions. In 2004 the LX2 plant was opened at Cartagena in Spain. Product developments include copolymer Lexan DVD and ecologically friendly compounds for electric and electronic components which are non-brominated and non-chlorinated flame retardant and which are intended to conform to WEEE, RoHS and certain voluntary ECO ecological standards. Other markets served include PCB as well as mobile phones and their associated battery cases. 

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