Our engineers went to the Hebei customer factory to carry out on-site installation and commissioning of the equipment.

Hebei customers purchased a UHMWPE rod extruder and an UHMWPE polymer tube extruder. Our engineers went to the customer site to install and debug the equipment. The installation process was very smooth and the equipment production quality was good.

The commissioning process was smooth, and the equipment was running well during the trial run. Our company also provided customers with recycled raw materials for testing, which saved customers from unnecessary waste during trial operation. Our engineers also provide guidance and training to the technical staff of the customer. The customer is very satisfied with our service.

Our engineers went to the customer site to install the dry grinding and returning machine.

Our engineers went to the customer site to install the dry grinding and returning machine.

The customer ordered a dry grinding and returning equipment from our company to dry-recycle the ptfe waste. Our ptfe waste recycling equipment consists of three machines, namely 1. washing machine 2. dry mill 3. electric sieve mill, the output can reach 40KG per hour.

1. Washing machine: Wash the waste in the washing machine, wash it with detergent, forcibly stir it, wash it once in half an hour, and wash 100-120 kg at a time.

2. Dry mill: put the cleaned PTFE waste into the dry mill and produce 30-40 kg/hour.

3. Electric sifting machine: After the dry grinding, the powder is placed in the automatic sifting machine. There are different mesh sizes such as 100 mesh, 80 mesh and 40 mesh, which can meet different needs. The powder with large particle size after sieving can continue to be placed. Grinded in a dry mill.

Belgian customers order six sintering.furnaces from us

Belgian customers order six sintering.furnaces from us

After careful consideration by many parties, the customer finally selected our products. After the customer visited the factory, they fully affirmed the strength of our company. The customer recognized the quality and service of our equipment, and finally chose to order 6 sintering.furnaces in our company. Our company can produce all kinds of ovens and sintering.furnaces such as: high temperature sintering.furnaces, PTFE oven, natural gas sintering.furnaces, vacuum sintering.furnaces, stainless steel oven, PTFE rotary sintering.furnaces, trailer type sintering.furnaces, etc. Our sintering.furnaces has double safety system, program control, It can automatically heat and cool down, can set 56 section temperature, has time control and ultra-high temperature double safety protection, good insulation performance, uniform furnace temperature, can set sintering curve, timing value and temperature value. The working temperature error in the furnace is ±1 °C, and there is no error within 1000 hours of operation. The inside of the hearth and the turntable made of stainless steel will not rust.

Company website:www.sukoptfe.com

Preparation technology of PTFE fiber

Carrier spinning method
Wet spinning
Wet spinning of PTFE usually in viscose or polyvinyl alcohol (PVA) as the carrier, mix with PTFE powder or emulsion dispersion, and add a small amount of boric acid, make spinning solution , perform wet spinning, spinning head placed in sodium sulfate and ammonium sulfate coagulation bath, dope from the nozzle in the coagulation bath solidified into fiber, fiber after leaching roller soft water leaching, again after oil roller and drying roller respectively, in 380 ~ 400 ℃ high temperature sintering, remove PVA carrier carbide, stretch to make PTFE fiber under 350 ℃. This method of spinning spend process cumbersome, high processing cost and energy consumption and time-consuming. Guo Yu-hai and others invented a highly efficient rapid method of preparation of PTFE fiber. This method will first evenly mix low relative molecular mass of volatile organic solvent with water, in under the condition of stir with PVA, continue to stir until completely dissolved, mixture of PVA water solution. Then the PVA water solution and persulfate, PTFE dispersion mixing uniformity, dope. Then borate or boric acid dissolved in water, with alkaline pH adjustment as alkaline, mixture coagulation bath. Finally adopt the wet spinning equipment of conventional , the spinning fluid conveying to the nozzle, through metering pump metering, direct spinning in the coagulation bath, then drying, sintering and stretch, the PTFE fiber is made.

Dry spinning

This method is PTFE gel realized by dry spinning. PTFE is first concentrated dispersion and PVA blended, add gel regulator boric acid or Borate salts and alkalis adjust the pH to alkaline, whisking to a sudden increase in the viscosity and gel formation, are spinning solution. And then dry them using conventional spinning equipment, gas pressure or screw spinning liquid to the spinning head, measured in metering pumps, dry spinning, and then dried, prepared mixture of PTFE and PVA fiber. Finally using conventional sintering and stretching equipment, will be mixed sintering to remove PVA fiber, finally after stretching process stretching, PTFE fiber preparation.

Carrier spinning method is the most mature method of preparing PTFE fiber, and has been one of the few companies to realize industrialization. Among them, Japan toray company USES mass fraction 60%, the average particle size was 0. 3 microns of PTFE, and the mass fraction of 2% sodium alginic acid aqueous solution of the emulsoid mixed spinning, the fiber by coagulation, bath again after washing, drying, and under 380 ℃ hot stretching, removal of alginic acid sodium, gain PTFE fiber, its monofilament linear density of 0. 67 dtex and fracture strength of l. 25 cN/dtex, elongation at break of up to 59%, the method of spinning dope spinnability better than with viscose as carrier of PTFE dope spinnability. Showa industries, the use of the 114 mass fraction of 60% PT – 100 FE dispersed emulsion and cellulose of mass fraction of 8.9% viscose spinning solution spinning, after solidification of the nascent fibers by water, squeeze liquid, with 0. 05 mol/L Na0H processing, and the fiber heat treatment under 280 ℃ and hot stretching under 320 ℃, the final heat treatment 72 h under 320 ℃, the fiber’s breaking strength for 1. 16 cN/dtex elongation at break was 16.1%. In addition, Beijing demonstration plant will be 60% mass fraction of PTFE emulsion and 10% mass fraction of PVA solution in proportion of 1:1.5 the spinning solution spinning, after solidification of the fiber by acetal, washing, drying, sintering and stretch to PTFE fiber system.

Cutting film splitting method
Cutting film crack method in the early 1970 s by the Austrian Lenzing company development and industrialization, in the preparation of PTFE fiber, need to make PTFE powder sinter cylindrical PTFE parison, cutting it up with a certain thickness of the film, and then by serrated tool divided into silk, above the melting point (327 ℃) sintering, then through stretching and end up with PTFE fiber heat treatment. This method can get the fiber with microporous structure, and high strength. Multifilament can be used as the sealing filler material, short fibers, can be used in the needle felt.

In addition, the PTFE film or sheet can also be cut into tiny width, and then direct tensile narrow fabric made of high strength PTFE fibers. But it is difficult to maintain uniform obtained by cutting along the longitudinal direction through the narrow width of the fabric, and narrow fabric tends to end part of fibril, so much stretch in narrow fabric PTFE fibers easily broken or through partial cutting in the longitudinal direction of the film are filament PTFE membrane orientation. Along the membranes of the longitudinal direction and in the transverse direction of the film with a z shape or linear-convex shape embossed and cut, the resulting filament including individual fibrils partially broken rule the network structure. PTFE fibers produced this way the individual fibrils with small average size and uniform size.

Japan Asahi of into Corporation through cutting film crack legal into has high stretch strength, and resistance chemical performance excellent of PTFE yarn. will containing hole rate 48% of PTFE film tear into 222 dtex of fiber, again on its added twist to 750 twist/m, in 440 ℃ and 1 000 m/min Xia stretch, get of fiber line density for 55 dtex, and containing hole rate 1%, modulus up to 294 cN/dtex.

Paste extrusion spinning method
Paste extrusion spinning usually PTFE powder 16% ~ 25% with mass fraction of volatile lubricants mixes, tune into a paste, made of shaped prefabricated embryos, and under certain pressure through a spinneret with a strip of die extrusion spinning, and then by drying, sintering, high stretch under high temperature, non-uniform white yarn. In addition, can also squeeze film extrusion equipment or thin strips, then by a rolling process to remove additives, and longitudinal cutting, drawing and fluffy after processing, are PTFE fibers were made by paste extrusion of thin wall, small diameter and permeability of PTFE hollow fiber. PTFE powder in conditions below its melting point made of PTFE hollow fiber, and then fired 10 min at 350 ℃, 250 ℃ under 400%, was 0.76 mm inner diameter and wall thickness of 0.10 mm, diameter of less than 0.15 mm hollow fibers.

In 1997, M. Shimizu proposes a method for preparing high strength and PTFE fibers by paste extrusion. Added to the PTFE powder mass fraction 20% of lubricants, embryo, extrusion, gained single wire, heated treatment and then 350 ℃ 1.5h, and 387 ℃ to 50 mm/min of speed stretching 10 times, received strength as much as 1.56 ~ 2.82 GPa PTFE fibers.

The PTFE powder was mixed with a lubricant (isoparaffin oil Isopar-E) to form a paste, standing at 0 ℃ 180 h at 40 ℃ cure 30 h, make the mix full wetting and swelling, then press embryo and extrusion , handle 2 h under 340 ℃, and then to 0. 5 c/min speed down to room temperature, finally stretching to get in a 370 c PTFE fiber, 3.5 ~ 4.0 cN/dtex the fracture strength, elongation at break is 22%.

Melt spinning method

Melt spinning is PTFE content to 4% ~5% of perfluorinated ethylene copolymer of perfluoro-n-propyl ether mixed spinning melt, after spinning by screw extrusion machines pump quantitative pressure injection hole, making it into a fine stream into the air, and cooling in the spinning channel into the wire. PTFE fibers high strength of this method, but PTFE supermolecular structure changes after melting, leading to its ductility disappeared and molecular chain orientation stretch is blocked, together with PTFE high viscosity and apparent flexibility, PTFE melt fiber prepared by screw extruder for direct comparison difficult, difficult to achieve industrialization. Plunger extrusion method can overcome this difficulty. The plunger in the extrusion process, due to extremely low surface energy of PTFE and wall-slip phenomenon, reduce unnecessary shear in the flow process, so they can be on PTFE melt spinning. Li Min and other person in Donghua university, are prepared by the PTFE fibre with high molecular weight. Tervoort by high relative molecular mass such as PTFE and PTFE mixed with low relative molecular mass, melt processing, preparing PTFE filament. Properties of PTFE fibers produced this way worse than that of pure PTFE fiber with high molecular weight.

The Manufacturing Process of PTFE

Making the TFE

1 Manufacturers of PTFE begin by synthesizing TFE. The three ingredients of TFE, fluorspar, hydrofluoric acid, and chloroform are combined in a chemical reaction chamber heated to between 1094-1652°F (590-900°C). The resultant gas is then cooled, and distilled to remove any impurities.

Suspension Polymerization

2 The reaction chamber is filled with purified water and a reaction agent or initiator, a chemical that will set off the formation of the polymer. The liquid TFE is piped into the reaction chamber. As the TFE meets the initiator, it begins to polymerize. The resulting PTFE forms solid grains that float to the surface of the water. As this is happening, the reaction chamber is mechanically shaken. The chemical reaction inside the chamber gives off heat, so the chamber is cooled by the circulation of cold water or another coolant in a jacket around its outsides. Controls automatically shut off the supply of TFE after a certain weight inside the chamber is reached. The water is drained out of the chamber, leaving a mess of stringy PTFE which looks somewhat like grated coconut.

3 Next, the PTFE is dried and fed into a mill. The mill pulverizes the PTFE with rotating blades, producing a material with the consistency of wheat flour. This fine powder is difficult to mold. It has "poor flow," meaning it cannot be processed easily in automatic equipment. Like unsifted wheat flour, it might have both lumps and air pockets. So manufacturers convert this fine powder into larger granules by a process called agglomeration. This can be done in several ways. One method is to mix the PTFE powder with a solvent such as acetone and tumble it in a rotating drum. The PTFE grains stick together, forming small pellets. The pellets are then dried in an oven.

4 The PTFE pellets can be molded into parts using a variety of techniques. However, PTFE may be sold in bulk already pre-molded into so-called billets, which are solid cylinders of PTFE. The billets may be 5 ft (1.5 m) tall. These can be cut into sheets or smaller blocks, for further molding. To form the billet, PTFE pellets are poured into a cylindrical stainless steel mold. The mold is loaded onto a hydraulic press, which is something like a large cabinet equipped with weighted ram. The ram drops down into the mold and exerts force on the PTFE. After a certain time period, the mold is removed from the press and the PTFE is unmolded. It is allowed to rest, then placed in an oven for a final step called sintering.

5 The molded PTFE is heated in the sintering oven for several hours, until it gradually reaches a temperature of around 680°F (360°C). This is above the melting point of PTFE. The PTFE particles coalesce and the material becomes gel-like. Then the PTFE is gradually cooled. The finished billet can be shipped to customers, who will slice or shave it into smaller pieces, for further processing.

Dispersion polymerization

6 Polymerization of PTFE by the dispersion method leads to either fine powder or a paste-like substance, which is more useful for coatings and finishes. TFE is introduced into a water-filled reactor along with the initiating chemical. Instead of being vigorously shaken, as in the suspension process, the reaction chamber is only agitated gently. The PTFE forms into tiny beads. Some of the water is removed, by filtering or by adding chemicals which cause the PTFE beads to settle. The result is a milky substance called PTFE dispersion. It can be used as a liquid, especially in applications like fabric finishes. Or it may be dried into a fine powder used to coat metal

Belgian customers order six sintering.furnaces from us

After careful consideration by many parties, the customer finally selected our products. After the customer visited the factory, they fully affirmed the strength of our company. The customer recognized the quality and service of our equipment, and finally chose to order 6 sintering.furnaces in our company. Our company can produce all kinds of ovens and sintering.furnaces such as: high temperature sintering.furnaces, PTFE oven, natural gas sintering.furnaces, vacuum sintering.furnaces, stainless steel oven, PTFE rotary sintering.furnaces, trailer type sintering.furnaces, etc. Our sintering.furnaces has double safety system, program control, It can automatically heat and cool down, can set 56 section temperature, has time control and ultra-high temperature double safety protection, good insulation performance, uniform furnace temperature, can set sintering curve, timing value and temperature value. The working temperature error in the furnace is ±1 °C, and there is no error within 1000 hours of operation. The inside of the hearth and the turntable made of stainless steel will not rust.

Company website:www.sukoptfe.com

PTFE Shaft Seals

Where High-Speed Seals Are Found

High speed rotary shaft seals are found in many applications.  Examples would include cryogenic deflashing equipment, vacuum pumps, torpedo shaft seals, gas turbine engine starters, and submersible dredge pumps.  AC/DC motors often require high speed shaft seals, and can be found in items like CNC tool spindles and dental or surgical instruments.  

Smooth Operation

Another key issue with high speed seals is the need for smooth operation, which means avoiding problems like stick-slip.  PTFE is an ideal material for avoiding stick-slip, and supports smooth, quiet operation.

Friction

Friction can make or break a high-speed seal.  At high speeds, the effects of friction have a greater impact on seal performance.  Shaft seals need to have extremely low friction, and since some applications may prohibit the use of lubricants, there is a good chance that the ideal polymer material for a high-speed seal will be self-lubricating.  

PTFE is ideal for addressing this challenge because it has the lowest coefficient of friction of any material known to man, and is also self-lubricating.  

Elevated Temperatures

One of the main challenges in high speed shaft seals is controlling temperatures.  High speed leads to increased heat generation.  Heat generation leads to dimensional changes, which means that a high-speed seal needs to have a small coefficient of thermal expansion to ensure dimensional stability.  

Another goal is to conduct heat away from seal, which means that along with a small coefficient of thermal expansion the seal material needs to have a high coefficient of thermal conductivity.  Not all heat can be conducted away, however.  A high-speed seal needs to be made of a material that can handle higher temperatures.  

PTFE can perform well in temperatures up to 500°F.  It has good thermal conductivity which can be greatly improved using carbon fillers, and has a low coefficient of thermal expansion which can be enhanced through fillers such as glass and carbon.

Efficiency

As already mentioned, high speed shaft seals are often used with AC/DC motors.  These are often small and may be battery powered, making efficiency a very important factor.  If losses can be minimized, efficiency can be maximized and have a positive effect on battery life.  A low friction material that promotes smooth operation is vital for these types of applications, and PTFE certainly fits that bill.