Engineering plastics generally refer to plastic materials that can withstand mechanical stress as structural materials and can be used in a wide temperature range and in harsh chemical and physical environments. Engineering plastics can be divided into two categories: general engineering plastics and special engineering plastics. General engineering plastics usually refer to five types of plastics that have been produced in large-scale industrialization and have a wide range of applications, namely polyamide (nylon, PA), polycarbonate (polycarbon, PC), polyoxymethylene (POM), polyester ( Mainly PBT) and polyphenylene ether (PPO). Special engineering plastics refer to plastics with more excellent and unique properties, but most of them have not yet been industrialized on a large scale or have a small production scale and relatively narrow uses, such as polyphenylene sulfide (PPS), polyimide (PI). ), polysulfone (PSF), polyetherketone (PEK), liquid crystal polymer (LCP), etc.
Engineering plastics have excellent properties and can replace metals as structural materials. Therefore, they are widely used in fields such as electronics and electrical, transportation, mechanical equipment and daily necessities, and their status in the national economy is becoming increasingly prominent.
Domestic production development status
The technological development of engineering plastics in my country has a history of nearly 40 years. Although it has a certain technical foundation, it is still in terms of technical level, production capacity and output. In other aspects, there is a huge gap with foreign countries, and some varieties (such as PPO) are basically blank.
In terms of business scale, most of my country's engineering plastics companies have 1,000-ton production equipment or industrial testing equipment, while the annual production capacity of foreign companies is mostly 10,000-ton or more. The huge differences in scale and process level make it difficult for domestic engineering plastics to meet the needs of the domestic market, and product performance and price cannot compete with imported products.
Characteristics and uses
Polyamide (PA) has unique low specific gravity, high tensile strength, wear resistance, good self-lubrication, excellent impact toughness, and has both rigidity and flexibility. It has won people's attention due to its performance. In addition, it is easy to process, has high efficiency, and has a light specific gravity (only 1/7 of metal). It can be processed into various products to replace metal, and is widely used in the automobile and transportation industries. Typical products include pump impellers, fan blades, valve seats, bushings, bearings, various instrument panels, automotive electrical instruments, hot and cold air conditioning valves and other parts. Each car consumes approximately 3.6 to 4 kilograms of nylon products. Polyamide consumes the largest proportion in the automotive industry, followed by electronics and electrical.
Although polycarbonate (PC) is a thermoplastic resin, it has strength similar to that of non-ferrous metals, as well as ductility and toughness. Its impact strength is extremely high and cannot be hit with a hammer. Being destroyed, it can withstand the explosion of the TV screen. Polycarbonate has excellent transparency and can be tinted in any color. Due to the above-mentioned excellent properties of polycarbonate, it has been widely used in various safety lampshades, signal lights, transparent protective panels in stadiums and stadiums, lighting glass, high-rise building glass, automobile reflectors, windshield panels, aircraft cockpit glass, motorcycle Car driving helmet. The markets with the largest usage are computers, office equipment, automobiles, alternative glass and sheet materials, and CD and DVD discs are one of the most promising markets.
Polyoxymethylene (POM) is known as "super steel" because of its superior mechanical and chemical properties, so it can be used as a material that many metal and non-metallic materials are not capable of. Mainly used for various high-precision small module gears, geometrically complex instrument precision parts, taps and gas pipeline valves. Our country uses polyformaldehyde for agricultural sprinkler irrigation machinery, which can save a lot of copper materials.
Polybutylene terephthalate (PBT) is a thermoplastic polyester. Compared with other thermoplastic engineering plastics, non-reinforced PBT has better processing performance and electrical properties. PBT has a low glass transition temperature and can crystallize quickly when the mold temperature is 50°C, resulting in a short processing cycle. Polybutylene terephthalate (PBT) is widely used in the electronics, electrical and automotive industries.
Due to its high insulation and temperature resistance, PBT can be used as flyback transformers for televisions, automobile distribution boards and ignition coils, office equipment casings and bases, various automobile exterior parts, air conditioner fans, electronic stove bases, office equipment Equipment casing.
Polyphenylene ether (PPO) resin has excellent physical and mechanical properties, heat resistance and electrical insulation, low hygroscopicity, high strength, good dimensional stability, and creep resistance at high temperatures. The most outstanding among thermoplastic engineering plastics. It can be used in washing machine compressor covers, vacuum cleaner casings, coffee appliances, hair stylers, massagers, microwave ovens and other small household appliances. Modified polyphenylene ether is also used in television components, connectors for telex terminal equipment, etc.
Demand status and forecast
With the rapid development of my country's national economy, the demand for engineering plastics in various domestic industries is growing rapidly, especially in domestic emerging industries and national pillar industries and new industries. Growth point industries such as electronics, automobiles, transportation, building materials, packaging, medical equipment and human organs require a large amount of engineering plastics with excellent performance, which has led to a rapid increase in the demand for engineering plastics in my country in recent years. In recent years, the demand for engineering plastics in my country has grown rapidly, with an average annual growth rate of 25%. In particular, the average annual growth rate of PBT, nylon, and PPO has exceeded 25%.
Based on the changes in the apparent demand for several engineering plastics in history, and taking into account the world scale and the latest market trends, the demand for five general engineering plastics was predicted. Since there are no good rules to follow in historical demand changes for PBT resin, we forecast the performance of PBT resin in the next few years based on the corrected apparent demand in 1998 and assuming that future demand development will be synchronized with GDP growth. Observe needs. By 2000 and 2005, my country's apparent consumption of general engineering plastics will reach 338,000 tons and 528,000 tons respectively. The average annual growth rate from 1999 to 2005 was 9.8%. After 2003~2004, the apparent consumption of polycarbonate is likely to exceed that of polyamide, becoming the most consumed general engineering plastic in my country. It is estimated that by 2005, the demand for polyamide will be 179,000 tons, polycarbonate will be 205,000 tons, polyoxymethylene will be 126,000 tons, PBT will be 11,900 tons, and modified polyphenylene ether will be 6,600 tons.