Development of Plastic Flame Retardant Technology
Advances in Plastic Flame Retardant Technology Cheng Zhiling Chen Wenjie (Resin Institute, Sinopec Corp., Zibo, Shandong 255400) 100% Polyester Mesh Fabric,Warp Mesh Fabric,Tulle Mesh Fabric,Mesh Knitted Fabric Dongguan Chuanchen Crafts Product Co., Ltd. , https://www.chuanchentextile.com
The field of plastics applications continues to expand, but it is flammable and has a high calorific value and is easily ignited, giving humans unexpected dangers and losses. Therefore, from the late 1960s, people began to pay attention to and emphasized the flame retardance of natural and synthetic materials. Flame retardants began to be the first class of important additives first in the chemical fiber and plastics industries. Since the 1970s, foreign flame retardants have begun to develop rapidly, and consumption and varieties have risen sharply, growing at an annual rate of 6% to 8%. Among the many additives in the plastics industry, the consumption of flame retardants has risen to the second place, becoming the second largest category of plasticizers. BCC expects the annual growth rate of flame retardant to be 5.2%, and it will reach US$924 million in sales in 2000. Flame retardants are generally divided into additive and reactive types. Additive flame retardant is mostly used in thermoplastics. It is the largest flame retardant in the world and accounts for 90% of total flame retardant production. Reactive flame retardants are mostly used in thermosetting plastics. Flame retardants can be divided into inorganic flame retardants and organic flame retardants according to chemical structure. Inorganic flame retardants include antimony compounds, inorganic boron compounds, inorganic phosphorus flame retardants, inorganic hydroxides, and the like. Organic flame retardants include organic halogen flame retardants and organic phosphorus flame retardants.
1 Development of flame retardant technology
1.1. Development of Antimony Flame Retardant The price of antimony trioxide is high, and the amount of fuming is large. Antimony trioxide is an indispensable synergist for halogen flame retardants. Therefore, the fineness of antimony trioxide must be finer and finer. , not only can greatly reduce the amount, improve the flame retardant, but also greatly reduce the amount of smoke. The current fineness is generally several microns to 0.01 μm. For example, the Patox average particle size developed by Seiko Co., Ltd. in Japan is 0.011 to 0.02 μm. Guizhou Qianjiang Fenghua Chemicals Factory recently successfully developed ultra-fine and high-purity active yttrium oxide with an average particle size of 0.02 μm and a content of 99.999%. Nya colADP480 PolycomHuntsman developed a particle size of less than 0. 1μm antimony pentoxide, and 1% may well play a role in PP flame retardant, and will not have the impact strength, transparency and the like PP impact. In addition, the use of antimony trioxide and aluminum hydroxide, zinc borate, borofluoride and other compounding, not only can reduce the amount of antimony trioxide, but also greatly reduce the amount of smoke. In short, ultra-finishing, seeking alternatives and reducing the amount of smoke is a hot spot for the development of antimony fire retardants.
1. 2 Development of Brominated Flame Retardants Although brominated flame retardants have a large amount of smoke, they are still flame-retardant, have a small amount of use, and have little effect on product performance. Therefore, they are still flame-retardant for quite some time to come. The main agent. With the advancement of technology, the new feature of the international development of brominated flame retardants is to continue to increase the bromine content and increase the molecular weight. For example, PB-68 from Ferro Inc. in the United States contains brominated polystyrene, a molecular weight of 15,000, and a bromine content of 68%. Polypentabromophenol acrylate developed by Bromo Chemical and Ameribrom, respectively, has a bromine content of 70 5% and a molecular weight of 30,000 to 80,000. These flame retardants are particularly suitable for all types of engineering plastics, and are much better than many small molecule flame retardants in terms of mobility, compatibility, thermal stability, flame retardancy, etc., and may become future replacement products.
1.3 Development of Phosphorous Flame Retardants Phosphorus-based flame retardants are mostly liquids and are mainly used in plastics such as PU and PVC. The main disadvantage of small molecular phosphorus flame retardants is their high volatility and low heat resistance. Efforts are being made to develop high molecular weight compounds and oligomers, such as the company Firemac ster836 GreatLake halogenated phosphate, containing phosphorus, bromine, chlorine, has a very low viscosity, particularly suitable for casting articles and the soft PU foam plastics [ 1]. Multi-functionalization with flame retardant and plasticization, flame retardance and cross-linking is another major aspect of the development of phosphorus-based flame retardants. Flame-retardant plasticizers (especially plasticizers at low temperatures) are mainly used in PVC products, such as domestic production of diisopropyl phenyl phosphate. Flame-retardant cross-linking agents are reactive phosphorus-containing polyols that can be used not only as a reactive flame retardant for PU, but also as a brominated flame retardant for use in epoxy resins, which can greatly reduce bromine flame retardancy The amount of agent. Phosphorus flame retardants in the future but also to the development of low toxicity, not only solved the toxicity of the product itself, but also consider the burning and decomposition products of toxic waste and environmental pollution, even considering the toxicity of production, sales, storage and transportation process problem.
1.4 Non-halogenated Inorganic Flame Retardant Development Most organic flame retardants contain halogens and emit large amounts of fumes when burned, resulting in toxic gases. Therefore, non-halogenated flame retardant materials have become more and more urgent in recent years. Some plastic products in some developed countries have begun to ban the use of halogen flame retardants. German environmental group PAL stipulates that bromide and bismuth oxide have been deactivated in the enclosure of electronic equipment since 1995. Sweden TC095 stipulates that organic bromide and organic chlorides are forbidden in all electrical and electronic equipment that exceeds 25 g in plastic parts. Although halogen flame retardants are still dominant in foreign countries, the trend of being gradually replaced by non-halogen flame retardants has become clear in the future. Inorganic flame retardants are an important part of non-halogen flame retardants. High-performance, non-halogenated inorganic flame retardants can be added in large quantities to polyolefins without affecting the mechanical properties of the product.
1. 4. 1 new aluminum hydroxide varieties
1.4.1.1 Develop new heat-resistant varieties (1) Increase the surface area of ​​aluminum hydroxide particles, ie, miniaturization and ultra-micronization, so that the partial pressure of water vapor on the surface of the particles can be reduced, and the heat resistance of aluminum hydroxide can be improved. Make the material mechanical properties, flame-retardant effect significantly enhanced. Experiments have shown that when the average particle size of aluminum hydroxide is 5 μm in the same formulation, the oxygen index is 28, and when the particle size is less than 1 μm, the oxygen index reaches 33 [2]. The new varieties Micral1000 and Micral1500 developed by American Solem Company have nominal particle diameters of 1.0 μm and 1.5 μm, respectively, and narrow particle size distribution, which can improve injection molding and extrusion processing. Hydrax series aluminum hydroxide from Climax Corporation of the United States has five varieties, each with a very narrow particle size distribution range. Alcoa's S-13 ultrafine aluminum hydroxide particle size in 0. 2 ~ 0. .5