Bromine-based environmentally friendly flame retardants are mainly bromine and chlorine-containing flame retardants. Bromine-containing flame retardants include aliphatic, cycloaliphatic, aromatic, and aromatic-aliphatic brominated compounds. Decabromodiphenyl ether, decabromodiphenylethane, brominated epoxy resin, and tetrabromobis are commonly used. Phenol A, hexabromocyclododecane, octabromo ether, etc. Among these, decabromodiphenyl ether, decabromodiphenylethane, and tetrabromobisphenol A are used in large amounts. Chlorine-containing flame retardants are mainly chlorinated paraffins. The advantages of brominated flame retardants are that they have almost no effect on the mechanical properties of the composite material. According to the flame retardant mechanism, the content of hydrogen bromide in the gas can be significantly reduced, and the flame retardants are compatible with matrix resins, even in harsh Under the conditions of no appearance. Their decomposition temperature is mostly around 200 ~ 300 ℃, which matches the decomposition temperature of various polymers, so it can play a flame retardant effect at the best time, when the gas phase and the agglomeration are the same, with a small amount of addition, the effect is good Good name.

Decabromodiphenyl ether The most talked about recently is that polybrominated diphenyl ether (PBDPO) will produce toxic carcinogenic polybromobenzoxanthene (PBDD) and polybrominated dibenzofuran (PBDF) when burned. For this reason, the world-renowned brominated flame retardant manufacturers have tested decabromodiphenyl ether flame retardants through a neutral agency, which shows that these products can pass strict German dioxin regulations and US Environmental Protection Agency regulations, that is, no The dangers of PBDD and PBDF. Therefore, DecaBDE flame retardants are still selling well in the United States, Japan and some European countries, and are used in a variety of polymers. The real carcinogenic products are octabromodiphenyl ether and pentabromodiphenyl ether. Decabromodiphenyl ether production in China has the fastest annual growth rate and the largest use. It is expected to produce nearly 25,000 tons this year, and foreign imports will not change much, so this year decabromodiphenyl ether will face Supply exceeds demand. The quality of some domestic decabromodiphenyl ethers is compared with imported products. The disadvantages are higher free bromine content, higher iron impurity content, and poor long-term storage stability. Although some factories have made improvements, they still need to do post-processing to be as good as imported products in quality.

Decabromodiphenylethane It is the best substitute for decabromodiphenyl ether developed in China in recent years. China's decabromodiphenylethane has grown rapidly in recent years, with an average annual growth rate of 80%, becoming the main force of the new generation of brominated flame retardants. Due to the dispute over decabromodiphenyl ether, scientists in the field of flame retardant research at home and abroad have been forced to find alternatives. The production process of Decabromodiphenylethane first introduced by Albemarle in the United States has become increasingly perfect. It is worth mentioning that, because of the application and production patent application of 8010 by Yabao, China's research and production units have been slow to carry out research in this area. However, it was found that the scope of Yabao's patents was outside China Can be produced and used in China, but it cannot be exported and patented. After learning about this situation, China's research on 8010 has begun in full swing. At present, it has industrial scale production in Shandong and Jiangsu, and the product quality has reached the technical specifications of Yabao Company in the United States. As an updated product of decabromodiphenyl ether, 8010 will be on the big stage of the flame retardant industry and become the main force of brominated flame retardants. China's decabromodiphenylethane has been successfully tested on an industrial scale at the end of the previous year. Last year Has begun to enter the market in batches. Decabromodiphenylethane has the same molecular weight and bromine content as decabromodiphenyl ether, so the flame retardancy is basically the same. However, decabromodiphenylethane has better heat resistance, light resistance and less dialysis than ten. Brominated diphenyl ether, the most valuable is that its flame retardant plastic can be recycled, which is a feature that many brominated flame retardants do not have. In addition, because the molecular structure of decabromodibenzyl has no ether structure, it will not form toxic polybrominated benzoxanthine (PBDD) and polybrominated dibenzofuran (PBDF), so its use will not be discussed There is a problem of polybrominated dioxins. Decabromodiphenylethane has been successfully developed and is welcomed by domestic manufacturers of flame retardant materials. Because it can replace similar foreign products, forcing the sales price of foreign products in the Chinese market to drop significantly (by 50%), the current price is only 3,000 yuan / ton higher than decabromodiphenyl ether. Decabromodiphenylethane is very competitive in the flame retardant market due to its excellent properties and is a flame retardant with wide application prospects. In addition, the comprehensive utilization of its by-product hydrobromic acid is a problem that needs attention.

Brominated epoxy resins As a newer flame retardant, brominated epoxy resins have received increasing attention in domestic and foreign markets. Because of its excellent melting rate, high flame retardant efficiency, and excellent thermal stability, it can also make the flame retardant material have good physical and mechanical properties without frost, so it is widely used in PBT, PET, ABS, nylon 66 and other engineering plastics, thermoplastics and PC / ABS plastic alloys in flame retardant treatment. Brominated epoxy resins are classified into three types: low, medium, and high according to their relative molecular masses. They can also be divided into EP and EC types based on the end group structure. They can be used in different plastic materials. Various domestically produced brominated epoxy resins with different molecular weights have already entered the flame retardant market. Manufacturers can choose matching brominated epoxy resins according to flame retardant standards to produce flame retardant materials with good heat resistance, light resistance, and good impact strength. The successful development of flame retardant brominated epoxy resin makes the flame retardant technology of thermosetting resin the best choice. Previously, brominated epoxy resins produced in China had low bromine content and small molecular weight, but were only used as insulation potting materials, and most of them were used in the copper-clad laminate industry. The flame-retardant brominated epoxy resin developed in the previous year is a bromine-containing epoxy polymer flame retardant with a high bromine content and a large molecular weight, which is different from the former. It is a white or almost white powder with a high Thermal stability and thermal aging performance, good processability, no dialysis, high UV stability and non-corrosive. According to the needs of different users, it can be synthesized into products with different molecular weights (molecular weights of about 6000, about 10,000, about 20,000, and about 30,000). According to the molecular weight of the flame retardant treated polymer, the matching brominated epoxy is selected. Resin, can achieve the best flame retardant effect and excellent comprehensive performance. At present, the production of this product in China has replaced similar foreign products, forcing the price of similar foreign products in China to be reduced.

Tetrabromobisphenol A In recent years, the production of tetrabromobisphenol A in China has developed abnormally and has reached a point of serious oversupply. The international environmental organization's disapproval of tetrabromobisphenol A has caused international manufacturers to reduce production. Therefore, many orders have rushed to China, forming a false demand market. As a result, many tetrabromobisphenol A factories of various sizes and scales were launched. After the supply and demand were balanced, the small tetrabromobisphenol A small factories were closed one after another, and those enterprises with excessive production capacity sought tetrabromo The development of bisphenol A downstream products, which is the current status of tetrabromobisphenol A production. Tetrabromobisphenol A is the world's largest and most widely used flame retardant. It can be widely used as a reactive flame retardant to produce brominated epoxy resins, phenolic resins, and bromine-containing polycarbonates. Other complex flame retardants can also be used as additive flame retardants for ABS and HIPS. The toxicity assessment of tetrabromobisphenol A and the risk reduction strategies of major European producing countries have a great impact on the production of tetrabromobisphenol A in China. See the attachment for details.

Hexabromocyclododecane (HBCD) products have three different crystal forms: alpha crystal form, beta crystal form, and gamma crystal form. How to make the α-crystal products with good heat resistance account for the largest proportion in the mixed system, and increase the melting point and heat stability of HBCD products is the first task for HBCD producers. How to choose three different crystal forms is very particular about the production process. How to control the amount of CDP, the amount of different solvents and Br2 will make the reaction product contain three kinds of mixtures in different proportions. In addition, the particle size distribution of hexabromocyclododecane should be in a relatively stable range. Excessive particle size distribution will affect its use effect. This is the aspect of hexabromocyclododecane to be improved in our country. The thermal stability of hexabromocyclododecane affects its use in the processing of flame-retardant products. Heat-resistant hexabromocyclododecane imported from abroad can maintain a stable structure at the general polymer processing temperature. And once burned, it does not produce too much smoke. HBCD with high heat resistance can be used alone or in combination with antimony trioxide in HIP, SEPS, XPS, PP and other homopolymers and copolymers.

At present, the domestic quality of octabromoether is basically equivalent to that of foreign countries. We must pay attention to improving the shape of the product. Foreign countries have changed from traditional powder to granular. In the past two years, major domestic manufacturers have also produced granular octabromoether. progress.

Brominated polystyrene The development of brominated polystyrene is similar to that of brominated epoxy resins. It is also a fast-growing flame retardant variety in recent years. Brominated polystyrene has the advantages of large molecular weight, good thermal stability, good dispersibility and compatibility in polymers, easy processing, and no frost. It is mainly used in thermoplastic resins such as PA, PBT, and PET. Brominated polystyrenes are named brominated polystyrenes and polybrominated styrenes according to their synthetic routes. It can be seen from the name that brominated polystyrene is completed by brominating polystyrene; polybrominated Styreneization is accomplished by first protecting styrene with ethylenic bonds, then brominating, recovering the olefinic bonds, synthesizing brominated styrene, and polymerizing again. From the use of solvents in the synthesis process, they can be divided into solvent methods and non-solvent methods. Because the solvent method consumes less bromine, it is usually synthesized by the solvent method. The polystyrene used for brominated polystyrene before bromination can be polystyrene pellets. Products produced from this raw material have a lighter color; recycled polystyrene plastic foam can also be used. It is dissolved in dichloroethane, filtered to remove impurities, and then brominated, which plays an environmental protection role and reduces costs. The main reaction in the entire synthesis process involves the bromination step. The bromination can be brominated by liquid bromine under the action of a catalyst, or by first synthesizing bromine chloride and then brominating. When using bromine as a brominating agent, a suitable low temperature should be used, and attention should be paid to the recovery of hydrogen bromide. A more active transition metal element should be appropriately used as a catalyst. When bromine chloride is used as a brominating agent, a medium-activity catalyst should be used. To control the reaction speed. In both synthetic methods, care must be taken to avoid the bromination of fatty carbon and inhibit free radical reactions, otherwise the thermal stability of the product will be reduced and product performance will be affected. Brominated polystyrene was a new product introduced abroad in the 1980s, entered the Chinese market in the 1990s, and began domestic research in the late 1990s, but did not achieve true industrial-scale production. The currently produced brominated polystyrene has a partial color. Yellow, poor stability. This is because polystyrene is a high molecular weight polymer, and bromine is a large elemental monomer. Its substitution reaction will encounter steric hindrance, and its bromination process is difficult. grasp. At present, domestic research units are using new processes to achieve industrialized scale production in combination with production units. Polybrominated styrene It is a polymer of brominated styrene. Brominated styrene monomer (such as dibromostyrene or tribromostyrene) is prepared first, and then this monomer is homopolymerized to obtain homopolymer bromostyrene or copolymerized with other monomers to obtain copolymerization. The copolymer may have functional groups, which can improve the compatibility of the copolymer with certain resins, thereby improving the heat resistance and fluidity of the flame retardant material, and preventing the material from foaming. This product has good whiteness and high thermal stability, but the process for the synthesis of brominated styrene is complicated. The equipment used is similar to the reactor with spiral propelling and different reaction temperature zones.

Tetrabromobisphenol A carbonate oligomer This is an additive type aromatic bromine flame retardant. It is produced by the reaction of tetrabromobisphenol A with phosgene. Because phosgene is dangerous, its storage, transportation, and production are very dangerous. Therefore, solid triphosgene is now used instead. Since triphosgene is also converted into phosgene in the reaction to participate in the reaction, it is necessary to pay attention to safety in production. Diphenyl carbonate has been reported to replace phosgene to produce tetrabromobisphenol A carbonate oligomers. Tetrabromobisphenol A carbonate oligomers are mainly used in flame retardant ABS, PBT, PET, PC, PC / ABS blends, polysulfones, PET / PBT blends, and SAN. Brominated carbonate oligomers are reinforced and unreinforced P