PTFE Polytetrafluoroethylene FEP Coated Sealing Ring FKM Fluororubber

PTFE Polytetrafluoroethylene FEP Coated Sealing Ring FKM Fluororubber, PFA Coated O-Ring Suzhou FEP Coated Sealing Ring Manufacturer, USP Medical Grade FEP Sealing Ring PFA Coated O-Ring Fluororubber FPM

Product Introduction:
Coated sealing rings (PTFE coated rings) organically combine the elasticity and sealing properties of rubber with the chemical resistance of Teflon. They consist of one or more inner cores made of Viton rubber (fluororubber) and a relatively thin outer coating of Teflon FEP (fluorinated ethylene propylene) or Teflon PFA (perfluoroalkoxy). This rubber-Teflon sealing ring offers excellent sealing performance. Rubber O-rings are prone to wear, have poor chemical corrosion resistance, and exhibit low gas permeability resistance. Pure O-rings have higher hardness and can resist compression but have poor elasticity. The outer coating of Teflon FEP/Teflon PFA O-rings provides excellent resistance to swelling and chemical stability (unless attacked by alkali metals, fluorine, and some halides at high temperatures). They maintain good elasticity near the rubber O-ring area. The friction coefficient of FEP/Teflon PFA is very low (only 0.1~0.2), and it has excellent gas permeability resistance. These properties make coated sealing rings suitable for use in harsh environments. Therefore, PTFE coated O-rings can replace expensive rubber O-rings.

Suzhou Yongxin Technology Co., Ltd. is a supplier of sealing components in motion and control systems, providing sealing solutions for transmission control, automation equipment, and aviation. The company sells various seals, hydraulic, pneumatic, and fluid control products and components. In terms of seals, Yongxin offers hydraulic and pneumatic sealing products, including dynamic seals, static seals, sealing rings, oil seals, gaskets, packing, and more.

Function:
The seamless and uniformly dense surface of the Teflon FEP/Teflon PFA outer coating, combined with the rubber inner core, ensures consistent sealing performance of the coated sealing ring. The elasticity and uniformity of the sealing ring remain intact at every point, allowing for repeated installation and use under continuous pressure. As the medium pressure increases, the entire sealing ring is compressed. The coated sealing ring behaves like a high-viscosity liquid, transmitting the pressure applied to it in all directions without reduction.

Main Advantages:
1. Outstanding chemical resistance, suitable for almost all chemical media 2. Excellent corrosion resistance 3. Wide temperature application range 4. Good durability 5. Friction resistance 6. Excellent swelling resistance 7. High-pressure resistance 8. Exceptional sealing durability and long service life

Structural Description:
Coated O-rings combine the chemical resistance of PTFE with the elasticity of rubber. They consist of an outer plastic coating and an inner rubber core, making them resistant to almost all chemical media (except soluble alkali metals, high-temperature fluorine gas, etc.). They are mainly used in pumps and valves, heat exchangers, boilers, filters, reaction vessels, pressure vessels, pipeline flanges, mechanical seals, gas systems, extraction equipment, etc.
Outer plastic materials include three types:
1. (FEP) Fluorinated Ethylene Propylene, temperature range -20°C to 200°C, general-purpose type;
2. (PFA) Perfluoroalkoxy, temperature range -20°C to 260°C, high-temperature resistant type;
3. Double-layer PTFE, temperature range -50°C to 260°C, for special corrosion resistance;
Inner rubber materials mainly include two types:
1. Silicone Rubber (SIL)
2. Fluororubber (FKM)
Others such as Nitrile Butadiene Rubber (NBR) and Ethylene Propylene Diene Monomer (EPDM) require customization.

Material Description:
Teflon FEP and Teflon PFA are essentially similar materials, but Teflon PFA has better high-temperature resistance than Teflon FEP.
Applicable temperature range for Teflon FEP coating: -60°C to 205°C, can be used at high temperatures up to 260°C for short periods. Teflon PFA coating: -60°C to 260°C, can be used at high temperatures up to 300°C for short periods. Solid coated sealing rings are widely used in both static and dynamic sealing applications. Hollow silicone rubber coated sealing rings generally have larger wire diameters and are used in static sealing applications. Their hardness and compression resistance are lower than those of solid coated sealing rings.
The manufacturing of coated sealing rings requires strict quality control. A special process ensures that the Teflon FEP polymer fully adheres to the rubber inner core, and the O-rings meet the required standard tolerances. Documentation indicates our strong commitment to quality for coated ring products, based on performance testing and strict controls to ensure customer satisfaction and safe use. Compared to any other rubber or pure Teflon O-rings, coated sealing rings offer unparalleled sealing performance and long service life, especially in harsh media.

Properties:
The presence of the FEP outer coating gives the coated sealing ring excellent resistance to hardening and brittleness. Meanwhile, the inner core made of silicone rubber or Viton rubber ensures that the sealing ring maintains good elasticity even at high temperatures up to 205°C.
A comparison of the sealing performance of three types of O-ring seals—Kalrez rubber (perfluoroelastomer), Viton rubber, and FEP-coated rings—in devices is shown in the figure. Test results indicate that coated sealing rings, which combine the physical properties of silicone or Viton rubber with the chemical properties of Teflon FEP/Teflon PFA, maintain rubber performance while offering excellent durability.

Chemical Corrosion Resistance
When in contact with Teflon FEP (recommended maximum temperature 204°C/400°F)/Teflon PFA (recommended maximum temperature 260°C/500°F), some highly concentrated chemicals may react. At high temperatures, Teflon FEP/Teflon PFA can be attacked by 80% NaOH and KOH, metal hydrides such as borane (B2H6), aluminum chloride, ammonia (NH3), and some organic acids (NH2) and amines (R=NH). At temperatures up to 250°C/480°F, they can also be affected by 70% chronic oxidation. If used under these conditions, the product must undergo special testing. Apart from the mentioned chemicals, coated rings are generally chemically inert to other substances.
The outer coating of Teflon FEP/Teflon PFA is a fundamental component of the coated ring, providing excellent resistance to chemical attack. Under normal operating temperatures, Teflon FEP/Teflon PFA is only attacked by a few chemicals. Here, only incompatible chemicals are listed, such as some strong alkali metals, fluorine, and some halides, which are not compatible with Teflon FEP/Teflon PFA.

Application Industries:
1. Chemical processing 2. Aircraft manufacturing 3. Pharmaceutical industry 4. Transportation of petroleum and chemicals 5. Oil refining 6. Film industry 7. Refrigeration engineering 8. Food processing industry 9. Paper industry 10. Dye manufacturing 11. Paint spraying 12. Pumps and valves 13. Reaction vessels 14. Mechanical seals 15. Filters 16. Pressure vessels 17. Heat exchangers 18. Boilers 19. Pipeline flanges 20. Gas compressors