Introduction to the most popular plastic flame ret

Introduction to the knowledge of commonly used plastic flame retardants

with the continuous expansion of the application field of plastics, it is flammable and its calorific value increases, and it is easy to ignite, which brings unexpected dangers and losses to mankind. Therefore, people began to pay attention to and emphasize the flame retardancy of natural and synthetic materials since the late 1960s. Flame retardants began to rise in the chemical fiber and plastic industries as a kind of important additives

since the 1970s, foreign flame retardants have developed rapidly, and the consumption and varieties have increased sharply, with an annual growth rate of about 6 ~ 8%. Among the numerous additives in the plastic industry, the consumption of flame retardants has jumped to the second place, becoming a large variety second only to plasticizers. BCC predicts that the annual growth rate of flame retardants will be 5.2%, and the global sales in 2006 will exceed US $1billion. Flame retardants are usually divided into additive and reactive types: additive flame retardants are mostly used in thermoplastics. They are the largest flame retardants in the world at present, accounting for 90% of the total output of flame retardants. Reactive flame retardants are mostly used in thermosetting plastics; Flame retardants can be divided into inorganic flame retardants and organic flame retardants according to their chemical structure. Inorganic flame retardants mainly include antimony compounds, inorganic boron compounds, inorganic phosphorus flame retardants, inorganic hydroxides, etc. organic flame retardants include organic halogen 2 flame retardants and organic phosphorus flame retardants

antimony flame retardant

antimony products are expensive and have a large amount of smoke, and antimony trioxide is an essential synergist of halogen flame retardants. Therefore, the requirements for the fineness of antimony trioxide particles are becoming finer and finer, which can not only greatly reduce the dosage, improve the flame retardancy, but also greatly reduce the smoke. Now the fineness is generally from a few microns to 0.01 μ m. For example, the average particle size of patox developed by Seiko Corporation in Japan is 0.01 ~ 0.02 μ m。 The ultra-fine and high-purity active antimony oxide developed by Guizhou Rongjiang Fenghua antimony chemical plant has an average particle size of 0.02 μ m. The content is 99.999%. Nyacoiadp480 developed by polycomhuntsman has a particle size less than 0.1 μ M antimony pentoxide, adding 1% can play a good flame retardant role in PP, and will not affect the impact strength and transparency of PP. In addition, the combination of antimony trioxide with aluminum hydroxide, zinc borate, fluoroborate, etc. can not only reduce the amount of antimony trioxide, but also greatly reduce the amount of smoke. In a word, ultra refinement, seeking antimony substitutes and reducing smoke are the development hotspots of antimony flame retardants

bromine based flame retardants

bromine based flame retardants are restricted by the European Union due to environmental protection problems despite their large smoke emission; However, due to its good flame retardancy, low dosage and little impact on product performance, it will remain the main force of flame retardants for quite a long time in the future. With the technological progress, the new feature of the development of bromine flame retardants in the world is to continue to increase the bromine content and molecular weight. For example, pb-68 of ferro company in the United States is mainly composed of brominated polystyrene, with a molecular weight of 15000 and a bromine content of 68%. The pentabromophenol acrylate developed by bromine chemical fast and ameribrom respectively has a bromine content of 70.5% and a molecular weight of 30000 ~ 80000. These flame retardants are especially suitable for all kinds of engineering plastics. They are much better than many small molecule flame retardants in terms of mobility, compatibility, thermal stability, flame retardancy and so on, and may become updated products in the future

phosphorus flame retardants

phosphorus flame retardants are mostly liquid and are mainly used in Pu, PVC and other plastics. The main disadvantages of small molecular phosphorus flame retardants are high volatility and low heat resistance Before the electronic measurement system has no potentiometer and other manually adjusted components, efforts are being made to develop high molecular weight compounds and oligomers. For example, firemacster836 of greatlake company is halogenated phosphate ester, which contains phosphorus, bromine and chlorine, and has a very low viscosity, especially suitable for pouring products and Pu soft foam plastics. Another major aspect of the development of phosphorus flame retardants is the versatility of flame retardant and plasticization, flame retardant and crosslinking. Flame retardant plasticizers, especially at low temperature, are mainly used in PVC products, such as diisopropyl phosphate produced domestically. Flame retardant crosslinking agents are some phosphorus containing polyols with reactive activity. They can not only be used as reactive flame retardants for PU, but also be used in epoxy resin together with bromine flame retardants, which can greatly reduce the amount of bromine flame retardants. Phosphorus flame retardants will also develop to low toxicity in the future, not only to solve the toxicity of the product itself, but also to consider the toxicity of combustion decomposition products and environmental pollution of waste products, and even to consider the toxicity in the process of production, sales, storage and transportation

non halogenated inorganic flame retardants

most organic flame retardants contain halogens, which produce toxic gases when burning. Therefore, the non halogenation requirements of flame retardant materials have become increasingly urgent in recent years. Some plastic products in developed countries have begun to prohibit the use of halogen flame retardants, and the EU's "two directives" on environmental protection have made clear restrictions on the formulation of the "smart car standard system construction plan". Previously, the German environmental group pal banned bromide and antimony oxide in the shell of electronic equipment since 1995, Swedish tc095 stipulates that all plastic parts with more than 25 grams in electrical and electronic equipment are prohibited from organic bromide and organic chloride. Although halogen flame retardants are still the mainstream in the world, the trend of being replaced by non halogen flame retardants has become clear. Inorganic flame retardants are an important part of non halogen flame retardants. High performance non halogenated inorganic flame retardants can be added to polyolefins in large quantities without affecting the mechanical properties of products

new varieties of aluminum hydroxide

develop new varieties, mainly including: (1) increase the surface area of aluminum hydroxide particles, that is, micro refinement and ultra-fine refinement, so that the partial pressure of water vapor on the surface of particles decreases, which can improve the heat resistance of aluminum hydroxide and significantly enhance the mechanical properties and flame retardant effect of materials. Some tests show that under the same formula, the average particle size of aluminum oxide for the daily inspection of hydrogen spring tension compression testing machine is 5 μ M, oxygen index is 28, particle size