Since the scientific and technological breakthrough of the 12th Five Year Plan, the technology and equipment of the rubber and plastic sealing industry have been greatly improved, and the product quality has also been greatly improved. However, with the continuous development of mechanical equipment for application sites with the extreme environment and harsh conditions, such as space exploration, polar scientific research, marine, and desert wind farm construction, deep well drilling and deep-sea operation, nuclear energy utilization, etc., it is required that the seal can adapt to the working conditions with higher pressure, faster speed, higher / lower temperature, lighter mass and greater impact. Therefore, the material research and development, manufacturing process, quality control and production scale of silicone rubber sealing products under extreme working conditions have become the development trend in the future.
Sealing of aviation hydraulic system
“Aviation equipment” is one of the high-end equipment innovation projects. In important national strategic plans such as “made in China 2025” and “medium and long term development plan of civil aviation industry (2013-2020)”, it is clearly pointed out to vigorously promote the development of aviation materials and basic components, develop advanced airborne equipment and systems, and form an independent and complete aviation industry chain. The airborne hydraulic system covers all parts of various aviation equipment such as large aircraft, helicopter and UAV. It undertakes the important work of aircraft control system, retraction and release system, wheel brake and ground steering driving. It is a key system to ensure the safe flight and landing of aviation equipment. Rubber plastic seal is the key basic part to ensure the safe and reliable operation of airborne hydraulic system.
With the progress of technology, the airborne hydraulic system is developing towards the direction of light weight, small volume, high pressure, high power and variable pressure, which requires the hydraulic sealing system to have a more compact structure and smaller section. At the same time, it has higher requirements for high pressure resistance, high temperature resistance, impact resistance and low friction and wear. For example, the pressure of the hydraulic seal system has been increased from 21 MPa to 35 MPa, and the pressure of 56 MPa and higher has also entered the research stage; The reciprocating speed is required to exceed 5 m / s, and the instantaneous speed can be up to 15 m / S; High and low temperature resistance is required to meet the wide temperature range of – 55 ~ 135 ℃. These changes have brought severe challenges to seals with high reliability requirements.
2.2 Sealing of deep sea drilling and production platform
Petrochemical deep-water regional development technology is one of the key technologies in China’s energy industry. As an important equipment unit of offshore deep-water oil and gas exploration and development, the sealing of offshore drilling and production platform has attracted the attention of many countries . Working in the harsh marine environment, the offshore drilling and production platform is not only affected by the loads such as ocean current, ocean wave, buoyancy, the external pressure of seawater, and platform movement, but also affected by many factors such as internal drilling fluid pressure, drill pipe friction, tension and so on; In addition, it is installed and connected by multiple components, and it needs to be removed and installed frequently with the drilling relocation of the platform and the change of sea conditions. Therefore, the safety and reliability of offshore drilling and production platform seal should be put in the first place in the design; Considering the convenience of use, the seal shall also have the characteristics of easy maintenance, simple operation, and strong adaptability. Deep-sea engineering equipment has special two-way sealing requirements for the sealing system. It is necessary not only to prevent the oil, gas, and other media in the equipment from leaking into the seawater but also to prevent the seawater from flowing back into the equipment. Especially in the deep-sea environment, the influence of pressure and seawater corrosion should be fully considered. The sealing temperature is as high as 177 ℃, the pressure is 103.4 MPa, and the content of hydrogen sulfide is as high as 20% (volume fraction), which is also a new challenge for the rubber and plastic sealing industry.
2.3 Sealing of new energy battery
“Energy-saving and new energy vehicles” is one of the high-end equipment innovation projects “made in China 2025”, and its technical core lies in the development of battery technology. At present, new energy vehicle batteries mainly include lithium iron phosphate batteries, ternary lithium batteries, and hydrogen fuel cells.
No matter what kind of new energy battery is used, the seal is essential. It is a key basic component related to battery life and safety. Lithium batteries contain a variety of metals and organic solvents such as an electrolyte. The electrolyte has considerable corrosivity and chemical toxicity. Electrolyte leakage will not only cause battery explosion and combustion but also produce toxic chemical gases and pollute the environment. Hydrogen fuel cell requires a high-pressure (35 ~ 70 MPa) storage system and fuel cell stack, and its safety is the key to the development of hydrogen fuel cell. Therefore, the sealing ring of the new energy battery is very important for the safety of the battery.
The battery silicone seal materials of new energy vehicles shall meet the requirements of insulation, strong corrosion-resistance, high-temperature resistance (≥ 200 ℃), impact resistance, and vibration resistance; The seal of hydrogen fuel cell also needs pressure resistance, low-temperature resistance, and good gas barrier. At present, the sealing reliability of domestic power lithium batteries is not high, and the service life can not meet the increasing requirements of battery life; Hydrogen fuel cell seals are mainly monopolized by foreign countries. However, in general, the battery technology of new energy vehicles is changing with each passing day, while the research in the field of battery sealing has just started, lacking systematic research, and foreign automobile sealing giants have not formed a monopoly position. Therefore, to carry out the research on the key technology of battery sealing simultaneously with new energy vehicle batteries is not only the need for the development of the sealing industry, but also the best time to build a complete industrial chain of new energy vehicles.
2.4 Semiconductor seal
Semiconductors play an irreplaceable role in the development of global science and technology and economy. With the rapid development of the Internet of things, 5g communication, and artificial intelligence, the demand for P semiconductors is increasing. China has become a major global semiconductor market, with demand accounting for more than 60%, and is the global semiconductor growth engine. However, the self-sufficiency rate of China’s semiconductor products is less than 30%, and the semiconductor industry is still in its infancy, which is far from developed countries such as Europe, America, Japan, and South Korea.
Among the more than 1000 processes in the semiconductor manufacturing process, the seal should ensure the harsh cleanliness and high vacuum of the environment and should withstand high temperature and the erosion of various chemicals, toxic gases, and plasma. It is the core and basic component of semiconductor production equipment. At present, it depends on the H port. Once foreign countries restrict the export of relevant products to China, it will greatly slow down the development of China’s semiconductor industry, which should be paid enough attention to by the domestic rubber and plastic sealing industry.
