Development and application of the hottest polymer

Development and application of polymeric brominated flame retardants recently, the EU exemption from decabromodiphenyl ether (DECA BDE) will undoubtedly have a far-reaching impact on the export of China's electronic and electrical industry. However, if the high purity of decabromodiphenyl ether cannot be guaranteed, it may still face the restrictions of relevant foreign environmental protection regulations. Polymeric brominated flame retardants have the characteristics of controllability, compatibility and stability, which can provide excellent flame retardancy of engineering plastics. Compared with other environmentally friendly flame retardants, they have greater advantages

flame retardants are a kind of functional additives that can effectively prevent the combustion of polymer materials and inhibit the generation of smoke and toxic and harmful gases. The most cost-effective varieties are brominated flame retardants, such as decabromodiphenyl ether, hexabromocyclododecane, etc

although the EU ROHS ban explicitly banned polybrominated biphenyls and polybrominated diphenyl ethers, and then exempted Decabrominated diphenyl ethers on October 15, 2005, the use of Decabrominated diphenyl ethers is not the only option, nor is it all the best choice, but only a choice with high cost performance. Bromine flame retardants similar to plastic bags are widely found in vegetable markets, snack bars and other places. The development way out should be based on the premise of green production and application, and start with the research of product structure to develop environmentally friendly flame retardants with high comprehensive cost performance. Albemarle, chemturo, ICL (formerly DSBG) and other companies have successively produced environmental friendly brominated flame retardants on a large scale, which can replace the limited polybrominated biphenyls and polybrominated diphenyl ethers

development status of flame retardants

the future development of flame retardants is to develop products that can better meet the following requirements: low price, easy to use, little impact on the physical properties of resin substrates, and friendly to the environment (recyclable, reusable, no corrosive and toxic substances). In terms of sales volume or sales volume, organic halides and inorganic compounds are the main flame retardants in the world. In the past 20 years, the output of organic halogen-containing flame retardants has always been increasing, but the corrosive and asphyxiating gases produced by the combustion of these flame retardants have a great negative impact on their use

the average annual growth rate of China's plastic products output is 10%, and the development momentum is not reduced. With the increase of the total amount of plastic products, the requirements for their safety and environmental protection performance are becoming increasingly stringent. The proportion of flame-retardant plastic products has increased rapidly, and safety and environmental protection regulations have also been issued frequently. In recent years, the total consumption of flame retardants in China has continued to increase. The annual average consumption growth rate can reach about 15%, far higher than the global average. Although the total output of flame retardants in China has increased rapidly, it still cannot meet domestic demand. It is estimated that in the next five years, the average annual growth rate of China's consumption of flame retardants will reach 12%. By 2008, the total demand will reach 110000-120000 tons. The national demand for flame retardants is expected to reach more than 170000 tons in 2005 and 200000 tons in 2010

impact of laws and regulations on the development of brominated flame retardants

brominated flame retardants (BFR) is the largest consumption of organic flame retardants, with a total global consumption of 250~300kt/a, accounting for 15%~20% of the total amount of flame retardants. At present, 80% of the flame retardants used in electronic and electrical products in the world are BFR

bfr has been produced and used for more than 30 years. At present, there are more than 70 kinds of BFR produced on a global scale, mainly decabromodiphenyl ether (DBDPO), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD). The output of the former two accounts for 50% of the total output of BFR

bfr has high flame retardant efficiency, wide application area, good heat resistance, excellent hydrolytic stability, and can meet the requirements of a variety of polymer processing processes and flame retardant products. It also has sufficient sources of raw materials, mature manufacturing processes, and low prices. However, there are also serious defects. Its flame-retardant polymers generate more smoke, toxic gases and corrosive gases during combustion, which reduces the photostability of the flame-retardant substrate, and some BFRs are easy to exude. Secondly, BFR is generally used together with antimony oxide, which makes the combustion smoke of the material higher

bfr has many disadvantages, but because of its high cost performance, BFR occupies a decisive position in the field of flame retardation. In many application fields, it is difficult to find a substitute for BFR

for this reason, developed countries and regions such as Europe, America and Japan have successively issued many laws and regulations to force users to use non-toxic and environment-friendly flame retardants, so as to achieve the goal of harmlessness of downstream products through the restrictions of laws and regulations

polymeric brominated flame retardants are the way out for the development of brominated flame retardants

although the problem of decabromodiphenyl ether, which has plagued the flame retardant industry for many years, has been solved, we still have to face the potential harm brought by brominated flame retardants. Although the use of decabromodiphenyl ether is no longer restricted by laws and regulations, its bromide saturated thermoplastic elastomer SEBS is still taboo because its soft segment is saturated olefinic structure

technicians in the flame retardant industry in various countries are also considering solutions, trying to find truly non-toxic and environment-friendly flame retardants or substitutes for brominated flame retardants at present

phosphorus flame retardants are the main products considered by insiders, although phosphorus halogen-free flame retardant pc/abs alloy, halogen-free flame retardant PA and halogen-free flame retardant PC have been successfully developed. DOPO, BDP, RDP, px-200, 201 and 202 are all representative products of this kind of flame retardants. However, the price of these halogen-free flame retardant materials is high, and their physical properties have decreased to a certain extent. It is still necessary to optimize their properties and reduce costs

silicon based flame retardants are another kind of non-toxic flame retardants of concern. The flame retardant is very effective in preventing PC combustion, and the physical properties of flame retardant PC are very close to those of non flame retardant PC, but the price has no great competitive advantage

in addition to the method of adding flame retardants, the molecular design of resins and the design of resin materials with flame retardant properties are also one of the flame retardant methods of polymers. Or copolymerization or blending and other material modification can achieve the flame retardant effect of the material itself. If PS is blended with PPO, the flame retardancy of PS can be improved even without adding flame retardant. The copolymer of PC and polysiloxane has excellent flame retardancy and almost the same physical properties as typical PC

in addition, the purpose of flame retardation can also be achieved by compounding nano inorganic materials with resin substrates, and nano inorganic materials also have a good reinforcing effect, increasing the disintegration speed of polymer materials under natural conditions, expanding the contact area with organic mold, which is conducive to environmental degradation. Research by Cornell University and the National Bureau of technology and standards (nitc) has proved that the peak heat release rate (HRR) of intercalated polymer/clay nanocomposites prepared from PC, PA6 and PP Grafted with maleic anhydride and clay is much lower than that of pure polymers. The reduction of heat release rate of ps/clay nanocomposites can be compared with PS with high content of decabromodiphenyl ether/antimony trioxide (a commonly used flame retardant of PS). For nanocomposites, only a small amount (3%~6%) of inorganic matter can be added to obtain flame retardancy. Nanocomposites with intercalation structure can be prepared by melt blending PS with montmorillonite modified by bis (dimethyl) bis (octadecyl) ammonium halide. The clay is treated with alkyl ammonium salt to remove the sodium ion on the clay, that is, it forms a hydrophilic clay instead of an organic one. Cone calorimeter measurement shows that the reason why resin/clay nanocomposites have flame retardancy is that it can form a carbon layer during thermal decomposition, which can be used as an insulating layer to slow down the escape of combustible fuels from polymers

although there are a large number of halogen-free flame retardant schemes, there is a common problem, that is, the price of new flame retardant materials is higher than that of bromine flame retardant materials. Therefore, bromine based non-toxic flame retardants have also become a way to replace the existing bromine based flame retardants with potential hazards. Polymerized brominated flame retardants have better solved the problem that the original brominated flame retardants may produce polyhalogenated dibenzo dioxane and polyhalogenated dibenzo furan, and become a new type of environmental friendly flame retardants

status quo of polymeric brominated flame retardants

polymeric brominated flame retardants are mainly brominated polymers obtained by polymerization of bromide monomers or bromination of polymers. This kind of polymer itself has extremely excellent flame retardancy, which can be endowed with the flame retardancy of polymer materials through addition and blending

types of polymeric brominated flame retardants

at present, polymeric brominated flame retardants are mainly brominated polystyrene (BPS), polybrominated styrene, brominated epoxy oligomer (BeO), brominated polycarbonate oligomer (BCO), poly (pentabromobenzoyl acrylate), PPBA, etc. Through molecular weight control, a series of flame retardants suitable for different resin matrices can be formed

brominated polystyrene is one of the main varieties of polymeric brominated flame retardants, including oligomers of polybrominated styrene (PBS) and brominated styrene. The main products on the market include saytex hp-3010, hp-7010 and pyro-chek 68pb of Albemarle company; ICL's fr803p, F-2000, F-2100, f-2200, f-2400, f-3100, phenoxy terminated carbon oligomer of TBBA, fr-1025; Bc-58, bc-52, etc. of chemturo

main characteristics of polymeric brominated flame retardants:

· polymeric brominated flame retardants are polymer additives, which have good compatibility with polymers and do not precipitate

· excellent photothermal stability. For example, the weight loss rate of saytex hp-3010 and hp-7010 of Albemarle under N2 protection and 320 ℃ for 60min is only 5%. Hp-3010 is heated to 340 ℃ under the protection of N2, and the molecular weight remains 80%

· no polyhalogenated dibenzo dioxane and polyhalogenated dibenzan will be generated

· non toxic, including its terminal application products, and there are no prohibitions worldwide

· good fluidity and process adaptability. For example, the MFR of hp-3010 reaches 67g/10min (235 ℃, 2.16kg)

· it is easier to form thin-walled and complex products, which is conducive to shortening the forming cycle and improving production efficiency

· recyclable and reusable

· it can reach the most stringent flame retardant standard UL94, class V-0

by controlling the degree of polymerization, the molecular weight of oligomers can be effectively controlled to form oligomers with different softening temperatures, which can meet the needs of different substrates

application of polymeric brominated flame retardants in engineering plastics (ETP)

polymeric brominated flame retardants can be applied to various resin substrates, especially to PA, PBT, ABS, abs/pc and other engineering plastic materials. On the premise of providing excellent flame retardancy to materials, polymeric bromine flame retardants not only have little impact on the mechanical properties of materials, but also help to enhance the fluidity and processability of resins

application of polymeric brominated flame retardants in PA

polymeric brominated flame retardants can be used in connectors on electronic circuit boards, electrical switches, auto parts, etc. When hp-3010, hp-7010, 68-pb of Albemarle company and polymeric brominated flame retardants of ICL company are used in 30% glass fiber reinforced PA66, polymeric brominated flame retardants have a good retention of Izod impact strength of the material, while PPBA brominated flame retardants have a significant improvement of Izod impact strength of 30% glass fiber reinforced PA6. Hp-3010 can double the Izod impact strength of 30% glass fiber reinforced PA66. However, the use of brominated polystyrene has a great impact on Gardner's impact strength, and there are obvious