China’s first sea-crossing high-speed railway between Fuzhou and Xiamen is coming, on which the cable-stayed bridge has been built successfully with the help of PTFE polytetrafluoroethylene, the king of plastics. Let’s talk about an application of PTFE that is little known to you.
Taicheng Xite Bridge is one of the bridges between Fujian and Xiamen High-speed Railway. The bridge is designed as an unbalanced rotating cable-stayed bridge with a total weight of 38,000 tons. The total length of the rotating part is 221.3 meters, which is the largest unbalanced rotating cable-stayed bridge of high speed railway in China in terms of tonnage.
How does such a huge object with such a tonnage complete a “gorgeous transformation”? This can’t be done without a high-performance fluoropolymer: teflon sliders. How can a small Teflon slide make a 10,000-ton bridge turn freely?
The basic principle of the rotating body is to set the ball hinge sliding layer between the upper and lower structure of the rotating body which is resistant to high pressure and has a small coefficient of friction. The ball hinge is composed of upper ball hinge, modified teflon slider and lower ball hinge, with the upper and lower ball hinges located in the upper and lower turntable.
In simple terms, the principle is similar to that of a stone grinding disc, where the base does not move and the upper part rotates around the grinding center. So the friction force between the ball hinges needs to be overcome during the traction rotation. How to reduce the frictional resistance is the key technical problem in the construction of the rotating body.
PTFE slider plays such a vital role due to its excellent self-lubrication, lowest dynamic and static friction coefficient, and wear and pressure resistance. After completing the installation of PTFE slider, the upper and lower ball hinges and the central shaft are coated with teflon powder grease lubrication medium, which can minimize the friction. In addition, the rotating shaft has PTFE tube, which can reduce the friction generated in the process of turning the body. Such a small PTFE slider should have such amazing energy!
Features of PTFE
● High temperature resistance
Its working temperature can reach up to 250 ℃.
● Low temperature resistance
It has good mechanical toughness at low temperature; even if the temperature drops to -196 ℃, it can keep 5% elongation.
● Corrosion resistance
It’s inert to most chemicals and solvents, and can resist strong acids and alkalis, water and various organic solvents.
● Good weather resistance
It has the best aging life among plastics.
● High lubrication
PTFE has the lowest coefficient of friction among solid materials.
● Non-adhesive
It has the lowest surface tension among solid materials, and does not adhere to any substance.
Applications of the king of plastics
PTFE can be made into sheets, tubes, rods, films, fibers and coatings according to product classification, and is widely used in various fields such as chemical, petroleum, textile, electrical and electronic, medical, mechanical and aerospace.
● Medical
PTFE is water resistant, physiologically inert, and non-adhesive, so it is used in many tissue repair materials and artificial organ materials, such as artificial blood vessels, and heart repair membranes, etc. PTFE can be sterilized using any method, and will not degrade when heated under high pressure or treated with various disinfectants. Therefore, it is widely used in medical devices such as sutures, sterile pads, and injection needles.
● Electronic and electrical
PTFE has excellent dielectric properties and extremely high thermal stability, and is an irreplaceable electrical insulation material, playing an important role in the field of electrical and electronic insulation. For example, PTFE glass lacquer cloth is used to produce high temperature and high frequency insulation materials, which can be used in satellite communications and computers; PTFE film is used to make capacitors as an insulation layer, padding and cables between instruments; PTFE thin-walled tubes of different calibers can be used for lead wire sleeves, heat shrinkage tubes and spiral tubes, and insulated lead pipes for generators, etc.
In the field of 5G communications, PTFE is also widely used in base station filters, high-frequency high-speed PCB/FPC, 5G chip process and high-frequency connectors and cables. Currently, the 5G filters used by major communication equipment vendors are still made of metal cavity filters, which use many PTFE components for support and insulation.
● Mechanical
For any kind of machine and equipment, lubrication should be conducted for mutual sliding surface during the operation to reduce the friction factor, reduce the wear and heat of the parts, ensure the normal operation capacity, accuracy and power consumption of machine and equipment. PTFE’s low coefficient of friction and self-lubricating properties allow it to be used in the manufacture of bearings, piston rings, machine tool guides and sealing materials, but it is usually used in precision instruments or acid and alkali resistant environments because it’s expensive.
● Textile
Expanded PTFE (e-PTFE) film is laminated with common fabrics to make waterproof and moisture permeable laminated fabrics. Its excellent characteristics of high strength, low shrinkage, non-stick and anti-UV aging enable e-PTFE fiber to become the fabric of choice for outdoor sports clothing. In addition, it is often made into firefighting suits, astronaut suits, medical protective suits, military combat suits, sleeping bags and lightweight tents.
● Automotive & transport
In the automotive oil seal material, it can isolate the parts that need lubrication in the transmission parts from the outgoing parts to prevent the leakage of lubricating oil. PTFE breathable film is used in automotive lights to balance the pressure inside and outside the lights and prevent the pollution brought by water, dust, and automotive fluids, etc.
● Chemical
PTFE, by virtue of its corrosion resistance, is used as an anti-corrosion material to make various anti-corrosion parts, such as pipes, valves, pumps and pipe fittings. For chemical equipment, it can make lining and coating for reactors, distillation towers and anti-corrosion equipment.
Find the best PTFE manufacturer
To make the most use of PTFE products, you’d better choose the best производитель ПТФЭ and SuKo, a China well-known PTFE tube manufacturer, is you best choice. Expert in PTFE/UHMWPE extrusion and products in various types and models, Suko stays forefront of the Tetrafluorohydrazine industry with technology innovation,profession and intelligence both domestically and abroad.
