Polyimide (PI) is a high temperature polymer, in 550 ℃ can keep short-term physical properties of major, long-term use of close to 330 ℃ at. In the high temperature resistant engineering plastics, it is one of the most valuable species. It has excellent size and oxidation stability, chemical resistance and radiation resistance, and good toughness and flexibility. Can be widely used in aviation / aerospace, electrical / electronic, automobile, locomotive, precision machinery and automated office machinery etc..
The aromatic heterocyclic structure is very stable with polyimide molecules, which reflects the excellent performance of other polymer materials can not be compared: resistance to tame and low temperature resistance, by biphenyl two anhydride and amine synthesis of benzaldehyde two PI, thermal decomposition temperature up to 600 ℃, is by far one of the higher thermal stability of the polymer in the variety. At such temperatures, short time basically can maintain the original physical properties. Can be used for a long time at 333 ℃, the other at -269 ℃ still not embrittlement; high mechanical strength, tensile strength of benzene type PI film can reach 170MPa, and biphenyl type can reach 400MPa, with the increase of temperature, the change is very small; radiation resistance; dielectric properties; chemical properties of stability, the acid, alkali is stable; in addition, the PI creep resistant ability, excellent friction performance.
In 2003 the global consumption of polyimide is about 35000 tons, about 50 more than the main manufacturers. At present, the consumption America, Western Europe and Japan has more than 20000 tons / year, of which American 13000 tons / year, is expected in 2004, consumption American, Western Europe and Japan will reach 27000 tons / year. America 14, Western Europe 11, Japan has 13 production plant for the production of PI. In addition, Russia, India, South Korea, China, Malaysia and China's Taiwan are a small amount of production and consumption of PI. Polyether imide (Ulterm) accounted for about 70% of the demand American PI, because of its good properties and processing characteristics, tendency and polyethersulfone, polyphenylene sulfide and other aromatic PI competition. Expected global over the next few years on polyimide demand will increased at an annual rate of about 10%.
Our country almost simultaneous with the world began to research and development of polyimide, has been basically formed, research and development of PI format, developed several varieties, such as benzene, trimellitic anhydride type, biphenyl two anhydride type, bisphenol A two anhydride type, single ether anhydride type, BTDA etc., and obtained the preliminary application. Now has nearly 20 manufacturers, production capacity has exceeded 800 tons. The 2002 PI film market, production capacity has reached 750 tons / year, 2003 6 manufacturers will add capacity of 400 tons / year, manufacturers to expand to 26. 4 factories film export, plus copper clad export, the export volume of nearly 70 tons / year. Now the main production manufacturers have Jiande City Solver Polyimide Co., Ltd. In 2001 the domestic output of about 400 tons.
In China, compared with foreign products in many varieties, has a great competitive advantage in price, therefore our country electric edge film market is basically occupied by domestic products, but also the domestic have begun to export products, such as the annual Northwest Research Institute of chemical industry to export 30 tons of BMI to Europe to Asia amide, also has a small amount of products are exported to Shanghai Research Institute of synthetic resin annually.
At present, the thermoplastic polyimide is mainly used for automobile engine parts, oil pump and pump cover, electronic / electrical instrument with high temperature socket, connector, printed circuit board and computer hard disk, carrier, integrated circuit chip inside the aircraft cargo systems.
Polyimide many varieties, but at present the main varieties of polyetherimide (PEI), polyamide imide (PAI) and bismaleimide (BMI) etc.. PEI is currently developing trend is the introduction of two benzene amine structure or other engineering plastic alloy, improve its heat resistance, or the composition of the alloy to improve its mechanical strength and polycarbonate, polyamide engineering plastics; PAI is polyimide varieties with high strength, the current development trend is to enhance the modification, as well as with other plastic alloy;BMI is a bifunctional compounds with maleimide as the active medium, similar to typical thermosetting resin activity and moldability, basically the same as the processing and molding of epoxy resin, is popular at present domestic R & D. In order to improve the application performance of polyimide, polyimide modification, development and application of composite materials and has become a research and development for quite a long time the polyimide hot, such as poly benzene diimide filled with graphite or PTFE, can significantly reduce the friction coefficient, used in automobile thrust washer, high temperature brake pads, windshield wipers, bearings, bushings and washers for aircraft turbine engine gas; polyimide glass fiber or boron fiber, known as super engineering plastic, used in the preparation of jet engine components;Silicon containing polyimide materials, can give good solubility, permeability, impact resistance, weatherability, adhesion; in addition to fluorinated polyimide.
Japan's NISSAN (Nissan) chemical company plans to improve its polyimide resin for LCD manufacturing yield exponentially. The company invested about 2000000000 yen ($18400000), in 2005 the first or second quarter, the polyimide resin device production capacity in Chiba to expand to 460 tons / year. In addition, the company also plans to spend 1000000000 yen, the micro chip production device in the Toyama county yield progress 60%. NISSAN's goal is, to 2007, the sales of products from 16000000000 in 2003 to about 50% yen progress. The polyimide resin is a kind of heat resistant super materials, help to display high-definition images in LCDs.
By Jiande City Solver Polyimidae Co., Ltd. provides funding support for research and development of a cutting-edge materials thermoplastic polyimide development success. This kind of special engineering plastics has ended the product of our country rely on imports situation for a long time, to fill the domestic blank. The thermoplastic polyimide not only has excellent mechanical properties, dielectric properties and heat resistance, corrosion resistance, wear resistance and other characteristics, but also overcomes the defects of the majority of polyimide insoluble and difficult processing, heat processing showed good characteristics, can by hot pressing molding, extrusion molding and injection method, composite and carbon fiber, glass fiber, PTFE, graphite, further stretching, progress of self-lubricating and wear-resisting properties of materials.The material can be made into a film, also can be molded into pipe, bar, and precision parts with complex structure, so it is an ideal material can replace metal, ceramic, thermosetting resin, low temperature thermoplastic plastics and difficult processing polyimide under given conditions. At present, the techn. At present, the technology has realized industrialization completely, and the formation of 200 tons / year plant capacity, the production of thermoplastic polyimide products can be used in automobile and aircraft engine, communication equipment, construction machinery, industrial machinery, commercial equipment, electronics and microelectronics, analysis and medical equipment and transmission and textile equipment etc. China's chemical industry, will promote the upgrading of products, so as to enhance the market competitiveness.
China's defense industry development and polyimide mainly with rapid development, research and application in some areas has reached the world level. The gap between advanced countries and abroad, mainly in small scale, is currently the largest domestic production plant for 100 tons / year, the developed countries is basically a kiloton size; China's product quality is poor, not stable, performance application; degree of fine product is not enough, few varieties, at present mainly in the poly pyromellitic polyimide films primarily, application fields are mainly film and plastic mold, and the varieties of foreign products variety, such as film, molding, coating, adhesive, coating, foam and fiber etc.. China should develop the existing varieties at the same time, vigorously develop the polyetherimide, poly diphenyl tetramethyl imide, thermoplastic polyimide and Polyethylene double main resin varieties imide larger amount.