Rubber-plastic seals are important basic components of mechanical products, which require high manufacturing accuracy. With the rapid growth of automobile manufacturing and automobile ownership in China, seals products need high-precision technology and equipment support both in structure and material. In recent years, some enterprises in the professional production of seals in our country conform to the market positioning, adjust the industrial structure and product structure in time, and grow rapidly. At the same time, the production value and output have been increased rapidly, and a great investment has been made in the production and testing experimental equipment.

Development Trend of Technology at Home and Abroad

Development Trend of Rubber-Plastic Sealing Materials

The formulation and processing technology of special rubber-plastic materials such as nitrile-butadiene, hydrogenated nitrile-butadiene, fluorine rubber, acrylate rubber and polytetrafluoroethylene, which are commonly used in rubber-plastic seals, are still the focus of work to improve the applicability and utilization of materials. The application of nano-materials will improve the mechanical properties and special functions of rubber-plastic materials. Among the first four national standards for nanomaterials issued and implemented by the National Standardization Committee on April 1 this year, one is the "nano-zinc oxide" standard for rubber.

Special engineering elastomer replaces low performance oil-resistant rubber; surface treatment of rubber bright surface; modification of rubber and plastic materials by nanotechnology and application of liquid rubber materials have made some progress in recent years. In particular, the recent application of some new materials has greatly promoted the rubber-plastic sealing technology.

The relatively weak thermoplastic elastomer (TPE) used in seals in China has the physical properties of vulcanized rubber and the processing properties of thermoplastic resin. The forming process does not need vulcanization, so TPE is regarded as the third generation of rubber. TPO, TPV and TPU have been widely used in the world: TPV's application in automobiles has increased by 15% annually, generally EPDN and PP's full crosslinking compound, which combines high tensile strength, oil resistance and heat resistance, can endure 150 C hot oil condition for a long time, and can be used to replace EPDM to produce automotive seals and other products; Ethylene propylene terpolymer (EPDM) and polyethylene (PE) are the most commonly used components. The production processes include mechanical blending and dynamic vulcanization. TPO produced by dynamic vulcanization. Rubber components up to 60-70%, wear resistance, ozone resistance, tear strength, compression deformation is small, comprehensive performance is better than EPDM vulcanized rubber.

TPO production facilities are continuing to be built in the United States, Western Europe and Asia. TPU has excellent processing properties of plastics and physical properties of rubber. It has excellent wear resistance, low temperature resistance and radiation resistance. It has made great progress in automotive, aerospace, medical and health, daily necessities, military materials and other industries. TPU can be widely used. For automobile shock absorber cushion, axle liner, bearing bush, bushing, airbag and other parts.

_New materials launched by domestic and foreign enterprises

1. Perfluororubber FFKM

High temperature resistance (250 ~320 C), gas resistance and strong chemical corrosion resistance, good elasticity, low compression permanent deformation, good elasticity and other advantages, adapt to some very harsh working conditions. It is applied in chemical industry, food industry, printing industry and semiconductor industry. Parker, Evco and other companies launched.

2. Fluoroplastics-coated rubber products

Fluoroplastics such as FEP (propylene fluoride) and PFA (perfluorinated compound), covering rubber O-rings and rubber gaskets (such as plate heat exchanger seal), improving the medium resistance of rubber products (solvent, strong acid, strong alkali), were introduced by Shanghai Yigang, EVCO, Fluorten and other companies.

3. Unique Polyurethane Materials

PU 92 AU 21100 has good lubricity, ultra-low temperature resistance up to 20K (- 253 C) and ultra-low temperature resistance. Simrit exclusively launched

4. Compound and Modification of Polytetrafluoroethylene (PTFE)

In order to overcome the shortcomings of PTFE such as poor cold flow and thermal conductivity and reduce product wear, PTFE material was used as matrix to compound with carbon fibers, polyimide (PI), polyether ether ketone (PEEK), polyphenylene sulfide (PPS) and other materials to develop oil-free lubrication seals (piston ring, guide ring, packing ring), which should be widely used in medium and high pressure oil-free compressors. Use. Guangyan Seal developed this kind of seals, used in many well-known compressors in China.

The application of expanded polytetrafluoroethylene (PTFE) and the new materials with strong toughness, porous and high fibrosis formed by stretching and expanding of expanded PTFE not only maintain the unique chemical stability of PTFE itself, extremely low friction coefficient and wide operating temperature, but also make it micro-fibrosis internal structure. The products have more tenacity than imagination.

_New product structure

In recent years, with people's attention to sealing technology, new sealing structures have been emerging, which meet the domestic market demand and promote to the international market in terms of technical level, quality level, cost-effective and other aspects.

1. New type of oil seal: The oil seal is equipped with a sensor to test the leakage of the seal (rotary seal), which can be used for on-line condition detection of equipment leakage. It is exclusively introduced by Simrit.

2. Evd Sealing System: After wear and deformation of cylinder seals, the internal pressure of the seals (elastomer) is adjusted by a special device to eliminate leakage, which is used for equipment with high reliability requirements (such as servo cylinder and hydraulic cylinder). Launched by Hunger Company;

3. The spindle with new SETCO AirShieldTM seal integrates the advantages of friction seal and labyrinth seal. The compressed air is fed tangentially into the circulating groove of the fixed front bearing seat, which together with the spindle forms a closed maze. Air flows around the spindle in the groove. Motion similar to eddy current produces uniform pressure to distribute airflow with uniform flow. It combines with flexible sealing lip, and the discharge air will blow the dirt away from the spindle, mainly the bearing.

4. Structural innovation of PTFE seals: PTFE seals derive many new structures, which are used in reciprocating seals, rotary seals and static seals, such as AQ seals, PTFE-V rings, universal seals and other sealing systems.

New developments in manufacturing equipment and testing instruments

Seals production equipment and testing technology are developing towards automation, low cost and high reliability.

In rubber mixing equipment, equipped with automatic mixer system and automatic control of mixing process, it can effectively achieve energy saving and high efficiency, reduce environmental pollution, and produce high-quality rubber mixtures. In order to improve the mixing effect and efficiency, the manufacturer's research focuses on the rotor shape of the mixer. Kobe Steelmaking Plant and Farrell Co. have developed 4WH and ST rotor mixers respectively. GK-E rotor developed by Mitsubishi Heavy Industries in Japan focuses on production efficiency.

In terms of moulding technology, rubber injection moulding technology with high efficiency, advanced and high quality is widely used abroad. The screw reciprocating injection machine for small products and the screw plunger injection machine for large-sized products can effectively improve the appearance quality and performance of sealing parts and save raw materials. Paker manufactures O-rings, which use injection machines to make products with very small flying edges. With the three processes of liquid nitrogen refrigeration trimming, plastic grain trimming and water-stone washing, the appearance of the products has reached a fairly high level.

In terms of vulcanization process equipment, many domestic sealing parts manufacturers are equipped with vacuum platen press and injection machine, and the ordinary platen vulcanizer is also heated by circulating oil to ensure the process stability.

Austria's Aconomos Company has made great breakthroughs in the traditional manufacturing of sealing rings. The company's machined equipment for seals can be machined to produce seals. It is suitable for the production of seals of various materials. Its market share is expanding year by year.

At the same time, the manufacturer also attaches great importance to the secondary development of the design software. It has good processing fluidity analysis ability of the die cavity materials. The precision of the NC equipment die has been widely used in processing and manufacturing, and the apparent quality has reached a fairly high level. It has greatly promoted the technological development of rubber and plastic sealing industry in China.

In detection technology, the latest development is the use of optical systems, such as Freudenbezy and other companies using the third generation of new optical systems developed by KMK company, which completely replaces manual detection, and successfully integrates the quality detection of seals into the production process. This image processing system achieves a very high detection speed and detection. Accuracy, can detect the smallest defects on the surface of seals, such as cracks, bubbles, impurities and slip lines.

Domestic seals enterprises have also introduced oil seal detection devices based on measuring lip tension of oil seals. The gas-sensitive detector (Italy), which measures lip seal performance by detecting pressure changes, has a high detection rate and can detect 1200-1800 oil seals per hour.

CNC machine tools have been widely used in processing and manufacturing, and professional die manufacturing companies have basically realized full CNC. The precision and apparent quality of the die have reached a fairly high level. At present, many domestic rubber and plastic seals enterprises are equipped with CNC processing equipment, and have accumulated a lot of experience in die design and processing application of CAD/CAM.

Suggestions on the Development of Sealing Industry

While machinery industry develops seven major equipment manufacturing fields, such as basic equipment, energy equipment, transportation equipment, raw material industrial equipment, modern agricultural equipment, environmental protection equipment, green manufacturing technology and equipment, and strengthens research on basic technology and common technology, it will also implement green system from micro-nano manufacturing technology as a starting point. The scientific development concept of manufacturing should extend the connotation of service and make the manufacturing industry advanced. In order to meet the development goals of machinery industry, rubber and plastic seals industry enterprises should pay attention to brand awareness, environmental awareness and standardization. Strengthen the research and development of independent intellectual property products, and promote the common technological progress of the industry.

Establishing National Brand and Promoting Advanced Service

At present, our industry is still dominated by a large number of general structural products with high homogeneity. In terms of brand creation, we do not have a well-known brand like "Parker", "Busak Shamban". We do not even have a well-known brand at the national level. Without excellent brand effect, it is not easy for users to distinguish the product quality level of each enterprise. Therefore, when choosing similar products, price is often the main choice factor, which leads to the vicious circle of mutual pressure within the industry and smaller profit margin.

_Strengthen the Application of Green Manufacturing Technology

Green manufacturing technology is the technical basis for implementing ISO14001; adopting green design technology; adopting clean energy to eliminate or reduce harmful emissions; adopting energy-saving technology to improve energy utilization; adopting precision forming technology to improve material utilization; non-toxic and low toxic process materials and processes to minimize harmful emissions; Vibration, low noise and low radiation process equipment; Waste recycling and reuse; End treatment and standard discharge.
_Standardization System Construction

The construction of standardization system is an important part of enterprise production, operation and management, a necessary condition for organizing modern socialized mass production, a prerequisite for realizing specialized production, is conducive to speeding up the development of new products, shortening the production cycle, saving raw materials and energy consumption, stabilizing and improving product quality. Important guarantee is the basis of realizing scientific and modern management, an important way of continuous improvement, an important measure of ensuring production safety and strengthening environmental management, which is conducive to the establishment of information systems, the use of information technology and the realization of technological progress.

Accelerating Specialized and Characteristic Production

At present, most rubber and plastic sealing enterprises in China focus on immediate benefits. As long as it is the needs of customers, regardless of size, no matter how much revenue, do whatever work, do business. As for the division of labor, their own characteristics and strengths, often do not care. It is difficult to form the best economic benefit model because of the same industry environment of 100 factories, low level repetition and no prominent competitive advantage. It restricts the development of enterprises and industries, and is not conducive to long-term development. Therefore, while seeking the current economic benefits, enterprises should take a long-term view and accelerate the realization of specialized and characteristic production.

Perfecting Technology Research Platform

Our government attaches great importance to and encourages the construction of technological research platforms, because all the new technologies that have been developed at a high speed all rely on technological research platforms to play a huge role. This is still relatively weak in the basic industry. There are Standardization Committee and hydraulic pneumatic seal Industry Association for rubber and plastic seals in our country. There is no national rubber and plastic seal engineering technology research and development center and its technological innovation system. Lack of industry technology platform makes it impossible for many main engine factories to find technical support in time.

In a word, with the rapid development of China's machinery industry, especially the development of automobile industry and electronic communication industry, China's rubber and plastic seals industry has irreplaceable practical significance and far-reaching connotation of industry development.

In the new international environment, the global rubber and plastic seals manufacturing base will continue to shift to China. China's rubber and plastic seals industry will also usher in a leap-forward development period, and will also make greater contributions to the development of China's new industrialization.