Rubber seals are important basic components of mechanical products, with high manufacturing accuracy requirements. With the rapid growth of automobile manufacturing and vehicle ownership in China, seal products require high-precision technology and equipment support in both structure and material. In recent years, some enterprises in the professional production of seals in China have adapted to market positioning, timely adjusted their industrial and product structures, and rapidly developed and grown. While rapidly increasing production value and output, significant investment has also been made in production and testing experimental equipment.

Domestic and international technological development trends

Development Trends of Rubber and Plastic Sealing Materials

Research on the formulation and processing technology of special rubber materials commonly used in rubber seals, such as nitrile, hydrogenated nitrile, fluororubber, acrylic rubber, and polytetrafluoroethylene, and improving the material's applicability and utilization rate remains a key focus of work. The application of nanomaterials will enhance the mechanical properties and special functions of rubber and plastic materials. One of the first four national standards for nanomaterials issued and implemented by the National Standardization Committee on April 1st this year is the "nano zinc oxide" standard for rubber.

Special engineering elastomers replace low performance oil resistant rubber; Surface treatment of rubber glossy surface; In recent years, some progress has been made in the modification of rubber materials and the application of liquid rubber materials through nanotechnology. Especially in recent times, the application of some new materials has greatly promoted rubber sealing technology.

In China, relatively weak thermoplastic elastomers (TPE) are used in seals, which have the physical properties of vulcanized rubber and the processability of thermoplastic resins. The molding process does not require vulcanization and is therefore considered as the third-generation rubber. TPO, TPV, and TPU, among the main varieties, have been widely used worldwide. TPV has an average annual growth rate of 15% in automotive applications and is generally a fully crosslinked compound of EPDN and PP. It combines high tensile strength, oil and heat resistance, and can withstand 150 ℃ hot oil working conditions for a long time. It can be used to replace EPDM in the production of automotive seals and other products; Currently, TPO is mainly composed of EPDM and polyethylene components, and the production processes include mechanical blending and dynamic vulcanization. TPO produced by dynamic vulcanization method. The rubber component is as high as 60-70%, with wear resistance, ozone resistance, high tear strength, and small compression deformation. Its comprehensive performance is superior to EPDM vulcanized rubber.

The United States, Western Europe, and Asia are all continuing to build TPO production facilities; TPU has excellent processing properties of plastics and physical properties of rubber, with excellent wear resistance, low temperature resistance, and radiation resistance. It has made great progress in industries such as automotive, aerospace, medical and health, daily necessities, and military supplies. TPU can be widely used in automotive shock absorbers, bushings, bushings, airbags, and other components.

New materials launched by domestic and foreign enterprises

1. Perfluororubber FFKM

High temperature resistance (250 ℃~320 ℃), gas resistance and strong chemical corrosion resistance, good elasticity, low compression permanent deformation, good elasticity and other advantages, suitable for some very harsh working conditions. Applied in industries such as chemical, food, printing, and semiconductor. Parker, Evco and other companies have launched.

2. Fluoroplastic coated rubber products

Fluorinated plastics such as FEP (fluorinated propylene) and PFA (perfluorinated compound) are coated with rubber O-rings and rubber gaskets (such as plate heat exchanger seals) to improve the medium resistance of rubber products (solvents, strong acids, strong alkalis). Companies such as Shanghai Yigang, EVCO, and Fluorten have launched this product.

3. Unique polyurethane material

PU 92 AU 21100 has good lubricity and can withstand ultra-low temperatures up to 20K (-253 ℃) for application in ultra-low temperature conditions. Exclusive launch by Simrit

4. Composite and Modification of Polytetrafluoroethylene (PTFE)

In order to overcome the disadvantages of PTFE such as poor cold flow and thermal conductivity, and reduce product wear, PTFE material is used as the matrix and compounded with carbon fiber, polyimide (PI), polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and other materials to develop oil-free lubrication seals (piston rings, guide rings, packing rings), which are widely used in medium and high pressure oil-free lubrication compressors. This type of seal developed by Guangyan Sealing is used in many well-known compressors in China.

The application of expanded polytetrafluoroethylene is a new material formed by stretching and puffing expanded polytetrafluoroethylene, which is strong, porous, and highly fibrotic. It not only maintains the unique chemical stability, extremely low friction coefficient, and wide operating temperature of polytetrafluoroethylene itself, but also its microfiber internal structure gives its products unimaginable toughness.

New product structure

In recent years, with the increasing emphasis on sealing technology, new sealing structures have emerged continuously, meeting the domestic market demand in terms of technical level, quality level, cost-effectiveness, and pushing towards the international market.

1. New oil seal: This oil seal is equipped with a sensor for testing the leakage of the rotating seal, which can be used for online status detection of equipment leakage. It is exclusively launched by Simrit;

2. Evd sealing system: After the wear and deformation of the oil cylinder seal, a dedicated device adjusts the internal pressure of the seal (elastic body) to eliminate leakage, which is used for equipment with very high reliability requirements (such as servo oil cylinders and hydraulic oil cylinders). Launched by Hunger Corporation;

3. The spindle with the new SETCO AirShieldTM seal integrates the advantages of friction seal and labyrinth seal. Compressed air is sent tangentially into the circulation groove of the fixed front bearing seat, forming a closed labyrinth together with the main shaft. Air flows around the spindle in the slot. The motion similar to vortex will generate uniform pressure and disperse the airflow at a uniform flow rate. It is combined with a flexible sealing lip, and the leaked airflow will blow away the dirt from the main shaft, mainly from the bearing;

4. Structural innovation of PTFE seals: PTFE seals have derived many new structures, which are applied in reciprocating seals, rotary seals, static seals, such as AQ seals, PTFE V-rings, flood seals, and other sealing systems for main seals.

There are new developments in manufacturing equipment and testing instruments

The production equipment and testing technology for seals are developing towards automation, low cost, and high reliability.

On the rubber mixing equipment, equipped with an automatic batching and fully automated mixing process control internal mixing machine system, it effectively achieves energy saving and high efficiency, reduces environmental pollution, and produces high-quality rubber compounds. In order to improve the mixing effect and efficiency, manufacturers focus their research on the shape of the mixer rotor. Kobe Steel Plant and Faurecia Corporation in Japan have developed 4WH and ST rotor internal mixers respectively, while Mitsubishi Heavy Industries' GK-E rotor focuses on production efficiency.

In terms of molding technology, efficient, advanced, and high-quality rubber injection molding processing technology is widely used abroad. The screw reciprocating injection machine for producing small products and the screw plunger injection machine for producing large-sized products effectively improve the appearance quality and performance of seals and save raw materials. Paker Company produces O-rings and uses injection molding machines to produce products with very small burrs. Combined with three processes of liquid nitrogen freezing trimming, plastic particle trimming, and water stone washing, the product appearance has reached a considerable level.

In terms of vulcanization process equipment, many domestic seal manufacturers have equipped vacuum flat plate machines and injection machines, and ordinary flat plate vulcanization machines have also been modified with circulating oil heating to ensure process stability.

Austria's Aikonomos company has made significant breakthroughs in the traditional production of sealing rings. The company's machining equipment for producing seals can use machining to produce seals, suitable for the production of seals from various materials, and its market share is expanding year by year.

At the same time, manufacturers also attach great importance to the secondary development of design software, and have good ability to analyze the processing flowability of mold cavity materials. In terms of processing and manufacturing, CNC equipment molds have been widely used with high precision, and the apparent quality has reached a considerable level. Greatly promoted the technological development of China's rubber and plastic sealing industry.

In terms of detection technology, the latest development is the use of optical systems, such as Freudenbezy's third-generation new optical system developed by KMK, which completely replaces manual detection and successfully integrates the quality inspection of seals into the production process. This image processing system achieves extremely high detection speed and accuracy, and can detect the smallest defects on the surface of seals, such as cracks, bubbles, impurities, and slip lines.

Domestic seal companies have also introduced oil seal detection devices mainly based on measuring the tension of oil seal lips, and gas sensitive detectors (Italy) that measure the sealing performance of oil seal lips by detecting changes in air pressure. They have a high detection rate and can detect 1200-1800 oil seals per hour.

Numerical control machine tools have been widely used in processing and manufacturing, and professional mold manufacturing companies have basically achieved full control. The precision and apparent quality of the mold have reached a relatively high level. At present, many domestic rubber seal enterprises have also equipped themselves with CNC machining equipment, accumulating a lot of experience in mold design and processing application CAD/CAM.

Suggestions for the development of the sealing industry

While developing seven major equipment manufacturing industries including basic equipment, energy equipment, transportation equipment, raw material industry equipment, modern agricultural equipment, environmental protection equipment, and green manufacturing technology and equipment, and strengthening research on basic processes and common technologies, the mechanical industry will also take micro and nano manufacturing technology as the starting point to implement the scientific development concept of green manufacturing, expand and extend the connotation of services, and make the manufacturing industry move towards advanced levels. In order to adapt to the development goals of the machinery industry, enterprises in the rubber and plastic seal industry should pay attention to brand awareness, environmental awareness, and standardization. Strengthen the research and development of independent intellectual property products, and promote the progress of common technologies in the industry.

Establish national brands and promote advanced services

At present, our industry is still dominated by a large quantity and wide range of ordinary structural products, with a high degree of homogenization. In terms of brand building, we don't have a well-known brand like "Parker" or "Busak Shamban", and we don't even have a nationally renowned trademark. Without a strong brand effect, it is difficult for users to distinguish the quality level of products from various enterprises. So, when choosing similar products, price is often the main factor, leading to a vicious cycle of mutual suppression within our industry and decreasing profit margins.

Strengthen the application of green manufacturing technology

Green manufacturing technology is the technical foundation for implementing ISO14001; Adopting green design technology; Adopting clean energy to eliminate or reduce harmful emissions; Adopting energy-saving processes to improve energy utilization efficiency; Adopting precision molding technology to improve material utilization rate; Non toxic and low toxicity process materials and processes minimize harmful emissions; Low vibration, low noise, and low radiation process equipment; Waste recycling and reuse; End of pipe treatment and compliance with emission standards.

◆ Standardization system construction

The construction of a standardized system is an important component of enterprise production, operation, and management. It is a necessary condition for organizing modern socialized mass production, a prerequisite for achieving specialized production, and conducive to accelerating the research and development of new products, shortening production cycles, saving raw materials and energy consumption for enterprises. It is an important guarantee for stabilizing and improving product quality, the foundation for achieving scientific and modern management, an important way for continuous improvement, an important measure to ensure production safety and strengthen environmental management, and to establish information systems, utilize information technology, and achieve technological progress.

Accelerate specialized and distinctive production

Currently, most rubber and plastic sealing enterprises in China are focusing on achieving immediate benefits. As long as it meets the needs of customers, regardless of the size of the scale or the amount of revenue, do whatever is needed and do whatever is needed. As for industry division of labor, personal characteristics, and strengths, they are often not very concerned. A uniform industry environment has been formed, with low-level repetition and no prominent competitive advantage, making it difficult to form the best economic benefit model. Restricting the development of enterprises and industries, which is not conducive to long-term development. Therefore, while seeking current economic benefits, enterprises should also have a long-term vision and accelerate the realization of specialized and characteristic production.

◆ Improve the technology research platform

The Chinese government attaches great importance to and encourages the construction of technology research platforms, because all rapidly developing new technologies rely on technology research platforms to play a huge role. This is still relatively weak in basic industries. China has established standardization committees and hydraulic and pneumatic seal industry associations for rubber and plastic seals, but has not yet established a national level rubber and plastic seal engineering technology research and development center and its technological innovation system. There is a lack of industry technology platforms, which makes it difficult for many host factories to find technical support in a timely manner.

In summary, with the rapid development of China's machinery industry, especially the automotive industry and electronic communication industry, the rubber and plastic seal industry in China has gained irreplaceable practical significance and profound implications for industry development.

In the new international environment, the global rubber seal product manufacturing base will continue to shift to China. The rubber seal industry in China will also usher in a period of leapfrog development, and will make greater contributions to the development of China's new industrialization.