English name of PTFE: Polytetrafluoroethene Abbreviation: PTFE
Aliases are: PTFE, tetrafluoroethylene, plastic king, F4, teflon and transliteration Teflon, Teflon, Teflon, etc.
PTFE is a special engineering plastic, and it is a material with corrosion resistance in the world today, and is known as the “Plastic King”. The main features are high and low-temperature resistance, corrosion resistance, high insulation, aging resistance, and self-lubricating. Its uses involve aerospace, electronics, chemicals, machinery and equipment, food and medical treatment, pumps, valves, pipelines, vehicles, ships, air compressors, etc., and become an indispensable material for solving many key technologies in modern industry.
The inert F atom in the PTFE molecule shields and protects the C-C bond, and the C-F bond is highly stable, and the molecular chain is difficult to be destroyed. It is a very stable structure. This molecular structure also explains the following excellent properties of PTFE.
Corrosion resistance: Except for a few solvents such as molten alkali metals and all-alkanes above 300℃, it can withstand the long-term corrosion of any other chemicals.
High and low-temperature resistance: can be used at -180+260℃ for a long time.
High lubrication: The friction coefficient is the smallest among solid materials, even ice can’t compare to it.
Non-sticking: The smallest surface tension among solid materials, without sticking to anything.
Weather resistance: the longest aging resistance life among plastics.
Non-toxic: The material can be used as an artificial blood vessel, non-toxic and non-allergic, and is a food and pharmaceutical grade material.
Insulation performance: A thick film of the newspaper is enough to withstand 1500V high voltage.
In addition, PTFE also has the characteristics of non-moisture absorption, non-flammability, and extremely stable to oxygen and ultraviolet rays.

Reinforced polytetrafluoroethylene (RPTFE) performance introduction

Reinforced polytetrafluoroethylene is also called modified, compounded, blended, and filled polytetrafluoroethylene. Referred to as RPTFE
Although PTFE has excellent comprehensive properties, it has disadvantages such as low mechanical strength, large linear expansion coefficient, poor wear resistance, poor creep resistance, and poor thermal conductivity. Under complicated working conditions such as mechanical strength, such as being used in the valve sealing industry, its actual limit safe use temperature is generally within -70~+150℃. In order to overcome these shortcomings, PTFE resin can be filled with reinforcing agents to improve the mechanical properties of the material and expand its application range.
Commonly used reinforcing agents are glass fiber, graphite, carbon fiber, carbon powder, polyphenylester, polyimide, molybdenum disulfide, ceramic powder, para-polystyrene, bronze powder, stainless steel powder, coloring agent and so on. According to the requirements of different working conditions, different proportions of reinforcing agents are prepared and mixed into PTFE. The material blending effect is similar to mixing sand and stones into cement. The mechanical strength of the blended material after filling is greatly enhanced, which can increase the wear resistance of PTFE by about 1000 times; increase the creep resistance by 1.5 to 4.5 times; bending The modulus of elasticity is increased by 2 to 3 times; the hardness is increased by 10% to 30%; the thermal conductivity is increased by 2 to 5 times; the linear expansion coefficient is reduced by about 1/2. Because PTFE is white, the color of the filled PTFE changes with the reinforcing agent, the density also fluctuates slightly, and the chemical properties also have the properties of fillers.
The improving effect of enhancer on polytetrafluoroethylene
Mainly improve performance
Carbon fiber, tin bronze powder, etc.
Improve mechanical strength, wear resistance, high-temperature resistance, and thermal conductivity.
Graphite, molybdenum disulfide, etc.
Improve lubricity, thermal conductivity and electrical conductivity.
Glass fiber, silicon powder, etc.
Improve mechanical strength and wear resistance.
Polyphenyl ester, polyimide, para-polyphenyl, etc.
Improve mechanical strength, high-temperature resistance, wear resistance, and not easy to damage the abrasive.
Although the cost of RPTFE is higher than that of PTFE, RPTFE has excellent mechanical properties, which obviously improves the service life of the whole machine and reduces the maintenance rate, thereby reducing the later cost investment. It is recommended to purchase RPTFE in consideration of long-term benefits.

Performance introduction of expanded polytetrafluoroethylene (E-PTFE)

Expanded PTFE English name: expanded PTFE, referred to as E-PTFE
E-PTFE material is a low-density pure PTFE product manufactured by a unique processing technology. He maintains some of the original properties of PTFE and has the flexibility that PTFE does not have. It is mainly used for sealing enamel, glass, plastic, potholes, pipes, containers, reactors, etc., especially for sealing equipment that requires corrosion resistance, high and low-temperature resistance, and brittle materials. The fields of use include chemical, aerospace, pharmaceutical, food and beverage industries.
E-PTFE has changed the shortcomings of ordinary PTFE materials such as excessive hardness, poor recovery, large thermal expansion coefficient, and easy failure after creep. E-PTFE has sponge-like flexibility, high compressibility, excellent acid and alkali corrosion resistance, non-aging, creep resistance, self-lubricating, low friction coefficient and high tensile strength. The microscopic E-PTFE is composed of countless homogeneous, dense, soft and strong multi-directional fibers. It has a unique high-density fiber structure. After pressure, the fibers will entangle each other and become a tighter and uniform structure, airtight, watertight, and The leakage performance is good, and it can maintain an excellent tightness under severe corrosive environment and high temperature.

Introduction to the performance of colored polytetrafluoroethylene

The natural color of PTFE is milky white, while colored PTFE is because of the PTFE base material filled with auxiliary materials. Excipients can be divided into two categories according to their purpose: enhancers and toners.
Toner: It is filled with toner in PTFE, which can be freely mixed into black, yellow, red, green, blue PTFE, etc. The toner only changes the color of PTFE. The filling ratio is very small. The original performance of PTFE can be ignored temporarily. Theoretically, the toner should affect the chemical stability, insulation, tensile strength and other mechanical properties of PTFE. , Some special occasions require attention, so I will ignore it for the time being. Colored PTFE is suitable for customers who have requirements for visual color.

Imported PTFE

Polytetrafluoroethylene (PTFE) resin was accidentally discovered by American scientists in the laboratory in 1936. Until now, there are less than 20 countries in the world that can produce PTFE, most of which are developed countries. my country mastered the production technology and put it into production in the 1960s. It has now become a major PTFE consumer. The supply of low- and medium-end products has exceeded demand, but many high-end products still need to be imported from developed countries.
At present, the main importing countries of PTFE raw materials and products in my country are the United States, Japan, and European countries. Due to transportation costs and supply cycle reasons, it is most common for my country to import PTFE products from Japan, and Japan’s imported PTFE products are of high quality and meet domestic high-end demand.
According to the feedback from end customers, the products exhibited creep resistance and high and low temperature stability under actual application conditions with mechanical strength, imported materials are better than domestic materials.
It is worth mentioning that although the mechanical properties of RPTFE will be significantly better than imported PTFE, the added enhancer will reduce the chemical stability and insulation properties of PTFE. For some food, medical, and chemical industries, pure PTFE is still needed. , And the performance of imported PTFE is better than domestic PTFE, suitable for high-end customer requirements.

Surface treatment and bonding of PTFE

Polytetrafluoroethylene (PTFE) is an engineering plastic with excellent comprehensive properties, and has become one of the important materials indispensable for cutting-edge science and modern industry. At the same time, PTFE material is recognized as a material that is difficult to bond due to its stable chemical properties, low surface energy, and difficult surface wetting. The way to solve this problem is to treat its surface to improve its surface adhesion, so that PTFE has a wider range of applications.
There are many surface treatment methods for PTFE, including sodium-naphthalene solution treatment method, plasma treatment method, electrolytic reduction method, high temperature melting treatment method, radiation grafting treatment method, metal evaporation method, etc. No matter which processing technology is used, it is to improve the bonding characteristics of the PTFE material surface. After surface treatment of PTFE materials by these methods, suitable adhesives can be selected according to working conditions to realize the bonding of PTFE to PTFE, metal, plastic, rubber, cement and other materials.
Among them, the sodium-naphthalene solution treatment method is the most effective, simplest, fastest, easy and cheap method among several methods recently studied. The method of operation is: sodium transfers the outermost electrons to the empty orbital of naphthalene to form anion radicals, and then forms ion pairs with Na+, releasing a large amount of resonance energy, forming a mixed solution of dark green metal organic compounds. These solutions are very active and can chemically react with PTFE, destroy the CF bond in the PTFE molecule, tear off part of the fluorine atoms on the surface, leave a carbonized layer on the surface and introduce some such as CO, C=C, OH , COOH and other polar groups. These polar groups increase the surface energy of PTFE, reduce the contact angle, and improve the wettability, thereby changing from difficult to sticky to sticky.