Introduction to knowledge of plastics flame retardants
plastics application fields constantly expanding its fuel and higher calorific value and easy to ignite, brings unexpected danger and loss. From the late 60 's people started to pay attention to and emphasis on natural and synthetic materials fire-resistant, flame retardant began as an important auxiliary first in chemical fibers and plastics industry rise.
since the 70 's flame retardant began to develop rapidly in foreign countries, consumption and a sharp rise in annual growth rate of about 6~8%. Flame retardant in the plastics industry a large number of additives consumption has jumped to 2nd place, becoming second only to the large variety of plasticizer. United States commercial communications Corporation (BCC) annual growth rate for flame retardants is expected 5.2%, 2006 global sales of more than $ 1 billion. Flame retardant agents: Add type and response type: Add-type flame retardants for thermoplastics, is currently the world's largest production of flame retardant, flame retardant 90% of the total. Reactive flame retardants used in thermosetting plastics; flame retardants classified according to the chemical structure of organic and inorganic flame retardants flame retardants, inorganic flame retardant mainly antimony compound, inorganic boron compounds, inorganic phosphorus flame retardant, inorganic hydroxides, organic flame retardants include organo-halogen flame retardant agent and organophosphate flame retardants.
flame retardant of antimony
antimony prices high, large amount of smoke, and antimony trioxide is essential collaborative halogen flame retardant agent, antimony trioxide particle fineness required more and more detailed, not only can greatly reduce the amount of increase flame resistance, and the amount of smoke is greatly reduced. Fineness are now several microns to 0.01 μ m, such as Japan's Seiko developed Patox average particle size for 0.01~0.02 μ m. Rongjiang, Guizhou Province Center of activity of antimony products chemical plant and development of ultra high purity antimony oxide, average particle size 0.02 µ m, 99.999%. PolycomHuntsman developed by NyacoIADP480 are particles smaller than 0.1 μ m antimony pentoxide, add 1% to good effect in the PP, and will not affect the PP impact strength, transparency, etc. Antimony trioxide with aluminum hydroxide, zinc Borate, Borate compound such as fluoride, antimony trioxide can be reduced not only the amount of and the amount of smoke is also greatly reduced. In short micro antimony, seeking substitutes and reduce the amount of smoke is developing hot spot of flame retardant of antimony.
brominated flame retardants
brominated flame retardants despite the large amount of smoke, because environmental problems restricted by the EU, but due to the small amount of fire-retardant properties, and little impact on product performance, still in quite a long time for the main force of the flame retardant. As technology advances the international brominated flame retardants on the development of new features is to continue to improve the bromine content and molecular weight increases. United States Ferro company PB-68 mainly composed of brominated polystyrene, molecular weight: 15000, bromine-containing 68%. Bromide chemical company and Ameribrom company developed poly v bromophenol acrylate, containing bromine weight 70.5%\ 30000~80000. These flame retardants are particularly suitable for all types of engineering plastics, migration, compatibility, thermal stability and flame resistance are much better than many small-molecule flame retardant agent, has the potential to become the replacement product.
phosphorus-based flame retardant
phosphorus-based flame retardants are liquid, mainly for PU, PVC and other plastics. Main disadvantages of low molecular weight phosphorus flame retardant is volatile, heat resistance is not high, efforts are being made to develop compounds of high molecular weight oligomers, such as GreatLake Firemacster836 for halogenated phosphate, phosphorus, bromine, chlorine, has a very low viscosity, especially suitable for pouring products and flexible PU foam plastics. Flame retarding and plasticizing, fire-retardant and cross-linking of multi-function is another major aspect of the development of phosphate flame retardants, fire-retardant plasticizer plasticization of especially low temperatures is mainly used in PVC products such as isopropyl phenyl phosphates in domestic production. Flame retarding Crosslinking agent is some class of reactive phosphorus polyols, can be employed as a reactive flame retardant agent for PU and brominated flame retardants used in epoxy resin, greatly reducing the amount of brominated flame retardants. Phosphorus flame retardant to the low toxic in the future development, not only solved the toxicity of the product itself, also taking into account the toxicity of combustion products, and waste pollution, even taking into account in the process of production, sale, storage and transportation of toxic problems.
non-halogenated organic flame retardant
most contain halogen organic flame retardant, smoke produces toxic gases when burned, so non-halogenated flame retardant material have become increasingly urgent in recent years. Developed of some plastic products has began ban using halogen flame retardant agent, EU on environmental of "two a instruction" has made clear limit, previously Germany environment groups PAL from 1995 began in electronic equipment of shell in the disabled bromide of real and the oxidation antimony, Sweden TC095 provides in electrical and the electronic equipment in the General over 25 grams of plastic parts are disabled organic bromide of real and the organic chloride real. Although halogen flame retardant in the world is still dominant, but were replaced by non-halogen flame retardant trend has been clear. Non-halogen flame retardants, inorganic flame retardant is a important part of high performance inorganic non-halogenated flame retardants can be added in polyolefin, and does not affect the mechanical properties of products.
hydrogen oxidation aluminum new varieties
development new varieties, main including: (1) increased aluminum hydroxide particles surface area that micro-refinement and the Super Micro-refinement, makes particles surface steam points pressure declined, can improve aluminum hydroxide heat performance and makes material mechanical performance, and flame retardant effect obviously enhanced, has test showed that also formula situation Xia aluminum hydroxide average grain diameter for 5 μ m Shi, and oxygen index for 28, and grain diameter <1 μ m Shi, and oxygen index reached 33, United States SOLEM company has developed a new variety of Micrai1000 and Micrai1500, the nominal size are 1.0 μ m, 1.5 μ m, and particle size distribution range and improvement of injection and extrusion processes. United States Climax Hydrax series aluminum hydroxide 5 varieties, have a very narrow particle size distribution range. Alcoa's S-13 Super-fine grain size between 0.2~0.5 μ m, strict control of particle size distribution and low Silicon content, as well as with the larger size of aluminium hydroxide mixture, to increase density and lower viscosity. (2) aluminum hydroxide react with high thermal decomposition temperature of the material, synthetic varieties of thermal decomposition temperature is somewhere in between, such as aluminium hydroxide and sodium carbonate crystals breaks down in 300~350℃ a total run off water and carbon dioxide, hydrogen chloride and tobacco has a strong inhibitory effect, are excellent flame retardant PVC and polyolefin. (3) reduction of insoluble aluminum hydroxide ions in particular sodium content, making mass fraction is less than 0.2%, such as: Japan light metal (strain) introduced varieties of high-purity aluminum hydroxide aluminium hydroxide concentration is greater than 99.9%, United States sOLEM company has developed a new variety of low content of sodium oxide ultrafine, large specific surface area, excellent electrical properties, can be used at 290.
new and improved surface varieties
aluminium hydroxide with silane coupling agent and titanate coupling agents and stearic acid (salt) such as surface treatment, this fledgling domestic, foreign new capabilities have been further development of surface modification of aluminum hydroxide agent. Solem company new process of silane treatment and treatment of organic silicone-coated aluminum hydroxide, in PP, PE add up to 60~70% can still be very good processing and physical and fire-retardant properties can improve.
Add a variety of inorganic Synergist. A small amount of flame retardant Synergist makes aluminum hydroxide filled material performance has greatly improved, such as inhibition of dripping, improved mechanical properties. With aluminum hydroxide can play a cooperative role in a wide range of inorganic flame retardant Synergist, mainly metal oxide and boric acid, zinc and phosphorus compounds (red phosphorus, phosphate), Silicon compounds, metal nitrate (nitric acid copper and silver nitrate), ammonium Polyphosphate, etc.
II is hydrogen oxidation magnesium new varieties, main including: (1) has many people think hydrogen oxidation magnesium can for hydrogen oxidation aluminum of substitutes, but due to hydrogen oxidation magnesium internal of physical crystal water, and strong polar, reasons, led to and poly olefin compatible sex poor, although I joint agent I joint Hou mechanical performance has improve but not too obviously, large fill hydrogen oxidation magnesium Yu poly olefin in the technology Shang also not mature. But low filling volume (<30%) of magnesium hydroxide and aluminum hydroxide total time increased with carbonation, and W[Mg (OH) 2]:W[AI (OH) 3]=1:1, and synergy in PE. (2) Morton international industrial chemical and additive company in Versamag702 fatty acids of the proprietary application on magnesium hydroxide, can improve the rheological and mechanical properties of filled polymer, added 50~60% filling the liquidity is still very good. Also useful to control micro-crystal growth method for preparation of magnesium hydroxide solid solution Finemagsn and its structure characterized by a high concentration of Divalent metal ions are mainly located near the Crystal surface and has a high acid resistant, waterproof, and joined in the formula below ordinary high-purity magnesium hydroxide.
expansion type flame retardant agent
expansion flame retardant polymer of research for polymer flame retardant technology opened has a new way, expansion flame retardant polymer basic overcome has traditional flame retardant technology in the of shortcomings, has following advantages: high flame retardant sex, and no melt drops behavior, on long time or repeat exposed in flame in the has better of resistance sex; no halogen, and no oxidation antimony; low smoke, and less HIV, and no corrosion sex gas produced. Expansion type flame retardant agent main components: (1) acid source, General refers to inorganic acid or can in burning heating Shi in in situ generated acid of salts, as phosphate, and sulfuric acid, and boric acid and the phosphate ester,; (2) carbon source, General refers to more carbon of multiple alcohol compounds, as quarter e four alcohol, and ethylene glycol and the phenolic resin,; (3) sent bubble source, containing nitrogen of more carbon compounds, as urea, and double cyanide amine, and polyamide, and urea aldehyde resin,. Study on intumescent flame retardant is mainly for PP, most commercially available in intumescent flame retardant PP, Pu. Such as Montefluos SpinflamMF82, with phosphorus and nitrogen as active collaborative components halogen-and antimony oxide, nitrogen-phosphorus-containing 21%, 18%. Flame retardant PP flame retardant 24% oxygen index of 37, flexural modulus 30~40%. There GreatLake NH-1197, NH-1151 etc. Until the early 90 's before it was committed to the study on flame retardancy of intumescent flame retardant PE and has achieved some good results.
smoke technology of
smoke in the fire are the first and most lethal factor and delaying the timing of fire, statistics show the death toll in the fire is 80% caused by asphyxia, so contemporary, "flame" with "smoke" on par, and for certain polymers such as PVC, "smoke" than "flame retardant" is more important. Halogen-containing polymers and halogen flame retardants and antimony compounds is the main source of smoke, in addition to non-halogenated flame retardant is the main way to reduce the amount of smoke outside, PVC halogen-containing polymers by adding smoke eliminating agent and compound of antimony trioxide is another measure to solve the smoke. Molybdenum is considered to be the best so far of smoke eliminating agent, such as Kegad911A of Shemlnwilliams company is including small amounts of zinc and molybdenum complexes, add 4% to reduce the amount of smoke in the PVC 1/3. Because of the high price of molybdenum, used zinc Borate, Ferrocene, aluminum hydroxide, silica compound and a small amount of molybdenum compound, is a more realistic way to solve the smoke problem, as Climax developed Moly-FR-201 is ammonium molybdate and aluminum hydroxide complexes, added to the PVC 5~10 smoke volume can be reduced by 43%.
microencapsulation flame retardant technology
prevents flame retardant of microencapsulated technology transfer, increase effectiveness, improving the thermal stability of flame retardant, change dosage forms, and many other advantages, of components between complex and synergistic and create multi-functional fire-retardant materials are also very favourable. Currently being explored, such as the Hunan Institute of plastics has developed the microencapsulation red phosphorus masterbatch, successfully used in PE, PP, PS, ABS resin, flame-retardant with good results. Anhui Research Institute of chemical industry development of microencapsulation of bromo phenyl phosphate esters, such as micro-encapsulation of chlorinated paraffin-70, also achieved very good results.
make joint technology
make joint polymer of flame retardant performance than line polymer good have more, so in thermoplastic plastic processing in the added few make joint agent makes polymer into part mesh structure, not only can improved flame retardant agent of dispersion, also conducive to polymer burning Shi in condensed phase produced knot carbon role, effective improve flame retardant performance and can increased products of physical mechanical performance, and resistance waiting, and heat performance,, as in soft quality PVC in the joined few quarter ammonium, makes its heated formed make joint of flame retardant material. Radiation can be used to join metal oxides and Crosslinking method can also make polymers.
direct production of flame retardant monomers technology
directly in front of the polymerization of monomers have flame-retardant, so as to make the resulting polymers flame retardant materials, but also a method of flame retardant.
along with the expansion of the field of development and application of synthetic materials, plastic wood, plastic and steel and cotton development needs of flame-retardant regulations and continuous improvement, flame retardant for plastics demand will increase year by year, should conduct researches in non-halogenated flame retardants on the direction, focusing on halogen-free inorganic flame retardant agents, development of phosphorus-based flame retardant.
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