In the complex world of industrial sealing, where failure is not an option, selecting the right material is paramount. For engineers, procurement specialists, and maintenance professionals facing extreme chemical, thermal, and purity challenges, one material consistently stands out: Polytetrafluoroethylene, or PTFE. At Kaxite Sealing, with decades of expertise in high-performance sealing solutions, we specialize in engineering superior PTFE O Ring products that deliver unmatched reliability and longevity.
A PTFE O Ring is not your standard elastomeric seal. While traditional O-rings rely on elasticity to create a seal, PTFE O-rings are typically machined from solid PTFE stock or skived tape. They offer a unique combination of properties that are simply unattainable with rubber or other polymers. Kaxite Sealing's PTFE O-rings are precision-manufactured to exacting tolerances, ensuring a perfect fit and optimal sealing force in your specific application, from semiconductor fabrication to aggressive chemical processing.
The decision to use a PTFE O-ring is driven by application requirements that push the limits of conventional materials. Here are the core advantages that make Kaxite Sealing's PTFE O-rings the preferred choice:
To ensure compatibility and performance, understanding the precise specifications of our PTFE O-rings is crucial. Below is a comprehensive breakdown of the standard parameters and available options at Kaxite Sealing.
| Property | Test Method | Typical Value | Units |
|---|---|---|---|
| Density | ASTM D792 | 2.15 - 2.20 | g/cm³ |
| Tensile Strength | ASTM D638 | 25 - 35 | MPa (psi) |
| Elongation at Break | ASTM D638 | 200 - 350 | % |
| Compression Set (22 hrs @ 25°C) | ASTM D395 | 40 - 60 | % |
| Continuous Service Temperature | - | -200°C to +260°C | °C |
| Thermal Conductivity | ASTM C177 | 0.25 | W/m·K |
| Coefficient of Friction (Dynamic) | ASTM D1894 | 0.05 - 0.10 | - |
Kaxite Sealing manufactures PTFE O-rings in a vast array of standard sizes. Our machining capabilities also allow for fully custom dimensions to meet non-standard gland designs.
| Standard | Inside Diameter (ID) Range | Cross-Section (CS) Range | Tolerance (Typical) |
|---|---|---|---|
| AS-568 (Inch) | 0.029" to 25.00" | 0.040", 0.070", 0.103", 0.139", 0.210", 0.275" | ±0.003" on ID; ±0.002" on CS |
| Metric (ISO 3601) | 1.00 mm to 500 mm | 1.00 mm, 1.50 mm, 2.00 mm, 2.50 mm, 3.00 mm, 4.00 mm, 5.00 mm | ±0.08 mm on ID; ±0.06 mm on CS |
Virgin PTFE can be modified with various fillers to enhance specific properties for specialized applications. Kaxite Sealing offers a range of filled PTFE compounds.
| Grade Name | Primary Filler(s) | Key Enhanced Properties | Typical Applications |
|---|---|---|---|
| Kaxite PTFE-V (Virgin) | None | Maximum chemical purity, best electrical properties, low friction. | Semiconductor, Food & Pharma, Chemical Analysis. |
| Kaxite PTFE-G (Glass) | Glass Fiber | Improved creep resistance, higher compressive strength, better wear resistance. | Heavy-duty static seals, valve seats, compressors. |
| Kaxite PTFE-C (Carbon) | Carbon Graphite | Superior wear resistance, higher thermal conductivity, excellent PV limits. | Dynamic seals, rotary applications, pumps, bearings. |
| Kaxite PTFE-S (Stainless Steel) | Stainless Steel Powder | Greatly increased rigidity, excellent creep resistance, high load bearing. | Flange gaskets, heavy compression loads, anti-extrusion rings. | Kaxite PTFE-B (Bronze) | Bronze Powder | High thermal conductivity, excellent wear resistance, good compressive strength. | Wear pads, bushings, thrust washers, compressor rings. |
Q: Can a PTFE O-ring be used in dynamic sealing applications?
A: Yes, PTFE O-rings are excellent for many dynamic applications due to their extremely low coefficient of friction and outstanding wear resistance, especially when filled with materials like carbon or bronze. They are commonly used in rotary shafts, reciprocating rods, and hydraulic/pneumatic cylinders. The key is proper gland design to account for PTFE's low elasticity and higher compression set compared to rubber. Kaxite Sealing engineers can provide specific design guidance for dynamic use.
Q: How does the compression set of PTFE compare to elastomeric O-rings, and what are the implications?
A: PTFE has a higher compression set (typically 40-60%) than high-performance elastomers like FKM (which can be as low as 10-20%). This means a PTFE O-ring may not recover its original shape as fully after prolonged compression. The implication is that PTFE O-rings rely more on their inherent sealing force and resistance to extrusion rather than on elastic recovery. Gland design must accommodate this characteristic, often using a tighter radial squeeze or backup rings in high-pressure applications to prevent gap extrusion.
Q: Are PTFE O-rings suitable for vacuum service?
A: Absolutely. PTFE is an exceptional material for high and ultra-high vacuum (UHV) applications. Its extremely low outgassing rate, minimal vapor pressure, and resistance to permeation make it ideal. For critical UHV systems, Kaxite Sealing recommends using our virgin, unfilled PTFE-V grade, which has been processed and handled to minimize surface contamination and particulate generation.
Q: What are the limitations of using a PTFE O-ring?
A: While versatile, PTFE O-rings have specific limitations. They are not truly elastic, so they are not ideal for applications requiring significant stretch for installation over a spigot. They have relatively poor radiation resistance compared to some elastomers. Pure PTFE can be susceptible to creep under heavy, continuous load (cold flow), which is why filled grades like PTFE-G or PTFE-S are used for such duties. Additionally, they are not recommended for applications involving molten alkali metals or certain fluorine compounds at high temperatures.
Q: How should PTFE O-rings be installed and handled?
A: Due to their machined nature, PTFE O-rings can be more delicate than molded rubber rings. Avoid using sharp tools for installation. For internal glands, a tapered installation cone is highly recommended. Ensure the gland and seal are clean and free of debris. Unlike rubber, PTFE does not typically require lubrication for installation, but a light film of compatible grease or the system fluid can sometimes aid in positioning. Handle with clean gloves to prevent contamination, especially for purity-critical applications.
Q: Can Kaxite Sealing provide custom-colored PTFE O-rings for identification?
A: Yes. While virgin PTFE is naturally white, Kaxite Sealing can incorporate FDA-compliant pigments to produce PTFE O-rings in various colors (blue, red, yellow, green, etc.) for easy system identification, quality control, or brand color-coding. This is a common request in complex fluid systems with multiple media or in the automotive and aerospace industries.
Q: What is the lead time for custom-sized or large-volume orders of PTFE O-rings?
A: Kaxite Sealing maintains an inventory of popular AS568 and metric sizes in key grades. For standard items, shipment is often within 24-48 hours. For fully custom machined sizes, large production runs, or specialized filler compounds, typical lead times range from 2 to 6 weeks, depending on the complexity and quantity. Our customer service team provides accurate quotes and timelines upon review of your technical specifications.
