polycarbonate
Polycarbonate (polycarbonate)
The abbreviation PC is a colorless and transparent amorphous thermoplastic material. Its name comes from its internal CO3 group.
chemical property
Polycarbonate is acid and oil resistant.
Polycarbonate is not resistant to ultraviolet rays and strong alkali.
physical features
Polycarbonate is colorless, transparent, heat-resistant, impact-resistant and flame-retardant, and has good mechanical properties at ordinary use temperature. Compared with polymethyl methacrylate, polycarbonate has good impact resistance, higher refractive index and good processability, and has UL94 V-0 flame retardant performance without additives. However, the price of polymethyl methacrylate is lower than that of polycarbonate, and large devices can be produced by bulk polymerization. With the continuous expansion of polycarbonate production scale, the price difference between polycarbonate and polymethyl methacrylate is narrowing.
Polycarbonate has poor wear resistance. Some equipment used for wearing polycarbonate needs special surface treatment.
history
Production and application
Polycarbonate is a common material in daily life. Because it is colorless and transparent and has excellent impact resistance, it is commonly used in daily life, such as optical disc, eyepiece, water bottle, bullet-proof glass, goggles, bank bullet-proof glass, headlights and so on. Animal cages, pet cages.
Polycarbonate is also used to make helmets and masks for lunar astronauts. Apple's ipod music player and ibook laptop case are also made of polycarbonate.
Impact on the environment
Food contact
Because of its transparency and toughness, manufacturers and buyers of food storage products like polycarbonate fiber. Compared with Shi Ying glass, polycarbonate fiber is light and fragile. Polycarbonate fiber is mostly used in disposable plastic water bottles and reusable plastic water bottles.
More than 100 studies have discussed the ecological response of bisphenol A leachate from polycarbonate fibers. Howdeshell et al. found that at room temperature, an endocrine interferon bisphenol (C 15H 16O2) (phenolmethane) seems to seep into the water from the polycarbonate fiber animal cage, which may be the reason for the increase of female reproductive organs. Vom Saal and Hughes' paper on the analysis of the impact of low-dose bisphenol A leachate published in August 2005 seems to find a hint that there is a relationship between financial support and conclusions: research funded by industry seems to tend to find no significant impact; Government-funded research often has a significant impact.
Easy to react with other substances.
Alkaline detergents such as sodium oxide should not be used in polycarbonate fiber, otherwise it will lead to the leakage of bisphenol A (C 15H 16O2), a known endocrine interferon (affecting reproductive system).
Polycarbonate PC is also a kind of material used for notebook computer shell. Its raw material is petroleum, which becomes polyester chip particles after being processed by the polyester chip factory, and then becomes finished products after being processed by the plastic factory. From a practical point of view, its heat dissipation performance is better than ABS plastic, and its heat dissipation is relatively uniform. Its biggest disadvantage is that it is fragile, and it will break when it falls.
Manufacturing state
Polycarbonate (PC) is the only transparent product among the five major engineering plastics, and its production capacity has increased rapidly at home and abroad. The global production capacity was about 654.38+850,000 tons in 2000, 2.2 million tons in 2006, 2.65 million tons in 2002 and 2.75 million tons in 2003, and it is expected to increase to 2.9 million tons in 2004 and 2005.
China's PC production capacity has been relatively low for many years, with only three enterprises maintaining production, with a production capacity of less than 5,000 tons/year and an annual output of about 2,000 tons. With the rapid growth of PC demand in China, there is an upsurge of PC joint venture and cooperative production of construction equipment in China. Bayer and Shanghai Huayi Chlor-Alkali Chemical Company have built a 200,000-ton/year plant in Shanghai Chemical Industry Park, and it is estimated that the first phase of the 50,000-ton/year plant will be put into production by the end of 2004. At the beginning of 2006, the second phase of the project reached 654.38+10,000 tons/year. In view of the huge demand of the PC market in China, the PC device will eventually be expanded to 200,000 tons/year. The device production is mainly optical products, which are used to produce CD, DVD discs and automobile lighting systems.
Teijin Chemical Company of Japan is building a factory with an annual output of 50,000 tons of aPC in Jiaxing, Zhejiang, which is expected to be put into operation in April 2005. The main raw material bisphenol A is supplied by Mitsui Chemical of Japan, and chlorine and caustic soda are produced by local enterprises. This product is a general product, which is mainly used to produce electrical components and auto parts. It is planned to add a set of 50,000 tons/year production equipment in 2006. At the same time, the company has built a 65,438+08,000-ton/year aPC and ABS composite device in Gao Qiao Free Trade Zone, which has been put into production at present, and plans to build a second 20,000-ton/year production line in the first half of 2005. Japan's Mitsubishi Gas Chemical Company plans to build a 654.38 million tons/year factory in Sichuan, which is expected to be put into operation in 2007.
In addition, some domestic enterprises cooperate with foreign countries or adopt domestic technology to build large-scale PC production devices, so PC production in China will enter a new stage in the next few years. In 2006, the domestic production capacity will increase to about 250,000 tons/year, and it will reach 500,000-600,000 tons/year in 20 10 ... In view of the huge PC market potential in China, famous foreign PC companies not only cooperate to build production devices in China, but also build large-scale devices in Taiwan Province Province of China, South Korea, Singapore, Thailand and other countries and regions. Investment in a variety of equipment is aimed at the China market. The main development trend of PC production technology is to develop non-phosgene synthesis technology to replace the interfacial polycondensation phosgene method, which is the main synthesis technology at present. GE Plastics and Bayer Company have developed their own non-phosgene production technology and put it into industrial production. In addition, Xu/Chimei, Mitsubishi Chemical/Mitsubishi Gas, Teijin Company and LG Chemical Company have developed non-phosgene technology, and are building or planning to build non-phosgene PC devices. Non-phosgene route will become the main production route of polycarbonate in the future.
market analysis
Since the late 1990s, China's demand for PC has shifted from the initial sand pipe in textile industry to the fields of electronics/electricity, CD-ROM, construction and automobile industry, and the demand has increased sharply. The domestic consumption was about140,000 tons in 1999, but it increased to 380,000 tons in 2003, with an average annual growth rate of about 28%, which was much higher than that of the national economy and other general engineering plastics. Because the domestic output is extremely small, the PCs used in China are mainly imported from abroad. From 1999 to 2003, China's net PC imports were138,000 tons, 235,000 tons, 2120,000 tons, 342,000 tons and 38/kloc-0,000 tons respectively, and a considerable part of smuggled PCs were not included, and the imported finished products were not considered.
From 65438 to 0999 -2003, the rapid growth of PC market in China was mainly driven by the demand for electronic and electrical products, hollow sunshine panels, CD and DVD discs, non-disposable drinking buckets and food containers. At present, the consumption structure of PC in China is roughly as follows: electronic appliances and computer accessories account for about 42%; Hollow sunshine board accounts for about 26.3%; CD and DVD discs are about13.1%; Drinking buckets and food containers account for about10.5%; Composite materials and automobile industry account for about 9. 1%. In the next few years, the original major consumption areas in China will continue to maintain a high-speed growth momentum, and computers and household appliances will continue to grow. In the future, the average annual growth rate of PCs in this field will be about10%-12%; With the construction of railways, highways, airports and cities, the demand for hollow solar panels is still strong. Moreover, in recent years, the economic benefits of domestic enterprises processing and producing panels with PC in the Yangtze River and Pearl River Delta are much better than those of many polymer resin manufacturers. It is estimated that the average annual growth rate of PC demand for hollow solar panels will be about 65,438+02-65,438+05%. At present, China has become the second largest consumer of optical discs in the world, and used to rely entirely on imported optical disc-grade PC production. With the production of Bayer Shanghai CD-ROM PC, the demand for CD-ROM will continue to grow at a high speed of more than 20% in the next few years. Experts predict that the fastest-growing domestic PC demand in the future will be PC-based * * * mixed metal composites, in which the automobile industry will be the main driving force. It is predicted that the average annual growth rate of PC demand in China will remain at 15%-20% in the next few years, and the domestic PC market demand will reach 550,000-650,000 tons/year in 2006. Domestic production capacity is still unable to meet the domestic market demand, and a large number of products will be imported from neighboring countries such as Japan, South Korea and Thailand to supply the domestic market.
The new varieties of PC/ABS alloy are mainly used in automobile industry.
At present, the global PC application has developed in the direction of high functionality and specialization. In view of the rapid development of PC production capacity and market demand in China, especially the construction of many large-scale devices in China and the rapid development of automobile industry, the PC industry in China will enter a new development stage in the next few years, and the most important thing is to speed up the application research of PC.
First of all, domestic production enterprises should make full use of the increase of domestic production capacity and the accumulated experience in plastic modification and plastic alloy to speed up the development, production and application of composite materials such as PC alloy. The most important thing is:
PC/ABS alloy, PC and ABS*** mixture can combine the excellent properties of PC and ABS, on the one hand, it can improve the heat resistance, impact resistance and tensile strength of ABS, on the other hand, it can reduce PC cost and melt viscosity, improve processability, and reduce the sensitivity of internal stress and impact strength of products to product thickness. At present, PC/ABS alloy is developing rapidly, with global output of about 850,000 tons/year and domestic demand of about 200,000 tons/year. Major companies in the world have developed and introduced new varieties of PC/ABS alloys, such as flame retardant, glass fiber reinforcement, electroplating and ultraviolet resistance, which are mainly used in automobile industry, computers, photocopiers and electronic and electrical components. The main domestic research and production companies are Shanghai Jieshijie Company, Changchun Institute of Applied Chemistry of Chinese Academy of Sciences, Lanzhou University and other units.
PC/PBT alloy, alloy material made of PBT and PC***, can improve the fluidity, processability and chemical resistance of PC. Japanese researchers used PC and PBT to prepare PC/PBT mixture in the presence of transesterification catalyst, which has good comprehensive properties and good transparency. Using glass fiber reinforced PC/PBT with refractive index similar to PC not only has excellent comprehensive performance, but also has good transparency, so it can be used as a glass substitute material. At present, foreign PC/PBT alloy products are mainly used in automobile bumpers, packaging film materials, automobile bases and seats. Domestic research has just started.
In addition, PC/PS (polystyrene) alloy, PC/PET (polyethylene terephthalate) alloy, liquid crystal polyester modified PC, PET/PCL (multiblock polyester polymerized from ethylene glycol, low molecular weight polycaprolactone and terephthalic acid) and PC*** were mixed and modified, and poly (1.
Secondly, we should keep up with the international development trend, the research of PC alloy materials is progressing, the application scope of PC is expanding, and the expansion of PC consumption field should be accelerated.
Wide-band light-transmitting optical instrument,
PC sheet is especially suitable for making spectacle lenses. The hardness and scratch resistance of PC can be improved by introducing siloxane groups into the molecular chain of PC. As a kind of high refractive index plastic, PC is used to make the core material of high temperature resistant optical fiber. If the C-H chain in PC molecular chain is replaced by C-F chain, the absorption of visible light can be reduced and the signal loss during transmission can be effectively reduced. In addition, PC has good light transmission, and has a wide range of applications and potential in transparent window materials, curtain walls of high-rise buildings, transparent building materials for airports and stadiums. In the future, the emphasis will be on improving the surface hardness and antistatic properties. PC chip is impact-resistant. Glasses lens thickness: ordinary resin sheet is thick, glass sheet is thick, middle folding resin sheet is thin, PC sheet and high folding resin sheet are thinner, and high folding glass sheet is the thinnest.
Flame-retardant and environment-friendly communication appliances are the focus of flame-retardant PC development in the field of communication appliances in the future. Therefore, pollution-free flame retardant PC materials have become the focus of development. Bromine flame retardants are rarely used because of their toxicity, while halogen-free and environmentally friendly phosphorus flame retardants will obviously reduce the thermal deformation temperature and impact strength of PC, so silicon flame retardants are more suitable. In addition, with the lightweight and miniaturization of communication appliances, higher requirements are put forward for PC materials. At present, PC/ABS alloy is especially suitable for communication appliances and aerospace industry.
The metallized automobile parts have good metallic luster and high strength after PC surface metallization, and are widely used in various automobile parts, but their impact toughness will decrease during electroplating. Therefore, the mixed modification of elastomer and PC dispersed the cracking stress, and its impact toughness would not be reduced even after electroplating. Therefore, electroplating grade PC resin has great development prospects. In addition, PC with metallized surface can also be used as a shielding material for electromagnetic waves and applied to computers.
For food containers with low residue of harmful substances, industrially synthesized PC is bisphenol A. Because a small amount of unreacted monomer bisphenol A remains in the resin during synthesis, it is easy to dissolve out when used as drinking water barrels and food containers, which affects people's health. Therefore, it is necessary to develop sanitary PC resin for the production and use of food containers such as drinking water barrels. As a packaging material and container PC for drinking water barrels, it has a very broad application prospect in China.
Among the anti-crack and embrittlement medical devices, PC has many excellent properties. At present, it has been used in medical devices. Because of its poor chemical resistance, it is easy to cause internal stress cracking in the presence of chemical substances. For example, PC is used in medical devices such as artificial dialyzer and artificial lung to solve the aging phenomenon of cracks caused by high temperature disinfection. If these shortcomings are overcome, the application of PC in medical devices can be rapidly expanded.
The application prospect of food packaging materials and container PC in China is promising.