When sealing systems face high pressures, aggressive chemicals, or continuous motion, material selection often determines whether the equipment runs reliably or fails prematurely. PEEK Filled PTFE has become a preferred solution for engineers who need more than virgin PTFE can offer. Kaxite Sealing supplies this advanced fluoropolymer compound in a range of stock shapes and precision-machined components, helping industries improve seal life, reduce friction, and control maintenance costs.
PEEK filled PTFE is a modified polytetrafluoroethylene compound in which a percentage of polyetheretherketone, commonly called PEEK, is uniformly dispersed into the PTFE matrix. The addition of PEEK particles changes the mechanical behavior of the base PTFE without sacrificing its well-known chemical inertness. Virgin PTFE is soft, creep-prone, and easily deformed under load. Adding PEEK increases compressive strength, improves wear resistance, and substantially reduces cold flow. The result is a sealing material that performs well in dynamic applications, high-pressure environments, and applications where dimensional stability is critical.
Kaxite Sealing produces PEEK filled PTFE with controlled filler content, typically ranging from 10% to 30% by weight depending on the service conditions. The material can be compression molded, extruded, or sintered into rods, sheets, and tubes. From these stock forms, precision seal rings, backup rings, valve seats, bearings, wear pads, and custom profiles can be machined to tight tolerances.
PEEK filled PTFE offers a balance of properties that is difficult to match with single-component polymers. The PTFE matrix provides a naturally low coefficient of friction and excellent chemical resistance. The PEEK filler contributes mechanical strength, hardness, and thermal stability. This combination makes the material suitable for demanding sealing applications where other thermoplastics may fail.
PEEK filled PTFE is used across industries where reliability and chemical resistance are non-negotiable. Kaxite Sealing works with original equipment manufacturers and maintenance teams to supply machined parts for the following applications:
Because PEEK filled PTFE can be machined to precise dimensions, it is often specified for retrofit projects and custom sealing systems where standard elastomer seals cannot survive the operating environment.
The following table lists typical physical and mechanical properties for Kaxite Sealing PEEK filled PTFE compounds containing 20% PEEK by weight. Actual values may vary slightly depending on filler content, molding method, and part geometry. Custom formulations are available upon request.
| Property | Test Method | Unit | Typical Value |
|---|---|---|---|
| Density | ASTM D792 | g/cm³ | 1.45 – 1.55 |
| Tensile Strength | ASTM D4894 | MPa | 18 – 25 |
| Elongation at Break | ASTM D4894 | % | 150 – 250 |
| Hardness | ASTM D2240 | Shore D | 60 – 70 |
| Compressive Strength at 1% Strain | ASTM D695 | MPa | 9 – 12 |
| Compressive Strength at 25% Strain | ASTM D695 | MPa | 30 – 38 |
| Dynamic Coefficient of Friction | ASTM D1894 | — | 0.08 – 0.15 |
| Continuous Service Temperature | Internal Method | °C | -100 to +260 |
| Melting Point of PTFE Matrix | ASTM D4591 | °C | 327 |
| Thermal Conductivity | ASTM C177 | W/m·K | 0.30 – 0.45 |
| Linear Thermal Expansion | ASTM E831 | 10⁻⁵/°C | 8 – 12 |
| Water Absorption | ASTM D570 | % | <0.05 |
| Flammability Rating | UL 94 | — | V-0 |
| Dielectric Strength | ASTM D149 | kV/mm | 18 – 22 |
Kaxite Sealing can supply PEEK filled PTFE with different PEEK loadings. The table below shows common filler percentages and their typical influence on performance.
| PEEK Filler Content | Hardness Trend | Wear Resistance | Creep Resistance | Common Use |
|---|---|---|---|---|
| 10% | Medium | Improved vs. virgin PTFE | Moderate | Low-load rotary seals, gaskets |
| 15% | Medium-High | Good | Good | Valve seats, backup rings |
| 20% | High | Very good | Very good | Spring-energized seals, compressor rings |
| 25% | High | Excellent | Excellent | High-pressure dynamic seals |
| 30% | Very High | Excellent | Excellent | Severe abrasive service, wear pads |
Kaxite Sealing maintains strict process controls for every batch of PEEK filled PTFE. Raw materials are sourced from qualified suppliers, and each production lot is tested for density, hardness, tensile strength, and filler distribution. Certificates of compliance and material test reports are available with every shipment. For customers in regulated industries, Kaxite Sealing can provide documentation supporting compliance with FDA, EU 10/2011, and RoHS requirements for certain grades. It is important to verify regulatory status for the exact filler content and application before final specification.
PEEK filled PTFE machines well with sharp carbide or polycrystalline diamond tools. Because the PEEK filler is harder than the PTFE matrix, tool wear is slightly higher than when cutting virgin PTFE. Recommended practices include using positive rake angles, moderate cutting speeds, and adequate chip clearance. Coolant is generally not required, but compressed air can help remove chips and control heat. For precision sealing components, Kaxite Sealing uses CNC lathes and milling centers to hold tolerances as tight as ±0.01 mm on critical diameters and ±0.05 mm on thickness. Stress-relieving after rough machining may be performed for parts with complex geometries or large cross-sections to improve dimensional stability.
Q: What is PEEK filled PTFE and how is it different from virgin PTFE?
A: PEEK filled PTFE is a compound made by dispersing polyetheretherketone particles into a polytetrafluoroethylene matrix. Virgin PTFE has exceptional chemical resistance and low friction, but it is soft and prone to creep under load. Adding PEEK raises hardness, compressive strength, wear resistance, and thermal stability. This makes the filled material better suited for dynamic seals, high-pressure backup rings, valve seats, and wear pads where pure PTFE would deform or wear too quickly. The filler does not significantly reduce chemical compatibility because both PTFE and PEEK are highly resistant to aggressive media.
Q: What are the main advantages of using PEEK filled PTFE seals?
A: The main advantages include a low coefficient of friction, excellent resistance to creep and extrusion, wide operating temperature range, and outstanding chemical compatibility. In sealing applications, these properties translate into longer service life, less maintenance, and lower energy losses due to friction. PEEK filled PTFE seals can handle continuous temperatures from -100°C to +260°C and withstand pressures beyond 30 MPa when properly supported by backup rings or spring energizers. The material also resists swelling in most solvents and hydrocarbons, making it a dependable choice for chemical processing, oil and gas, and hydraulic equipment.
Q: Can PEEK filled PTFE be used in food contact or pharmaceutical applications?
A: Yes, certain grades of PEEK filled PTFE can be formulated to meet FDA and EU food contact requirements. However, not every filler loading is automatically food compliant. Kaxite Sealing offers FDA-compliant PEEK filled PTFE grades for applications such as seals in food processing equipment, pharmaceutical mixers, and beverage filling lines. Customers should specify the exact regulatory standard they need, such as FDA 21 CFR 177.1550 or EU 10/2011, so that the correct raw materials and production documentation can be provided. The final component must also be evaluated for the specific food type, temperature, and cleaning chemicals used in the process.
Q: What is the maximum operating temperature for PEEK filled PTFE?
A: The continuous service temperature for PEEK filled PTFE is typically -100°C to +260°C. Short-term exposure to temperatures up to 300°C is possible in some static applications, but the mechanical strength of the PTFE matrix begins to decline above 260°C. When specifying a sealing system, it is also necessary to consider pressure, sliding speed, and chemical environment. Under high load at elevated temperatures, PEEK filled PTFE retains more dimensional stability than virgin PTFE, but the actual temperature limit should always be confirmed by application testing or consultation with Kaxite Sealing engineers.
Q: How does PEEK filled PTFE perform in abrasive or high-pressure environments?
A: PEEK filled PTFE performs significantly better than virgin PTFE in abrasive and high-pressure conditions. The hard PEEK particles reinforce the softer PTFE matrix and resist abrasive wear from particles or rough mating surfaces. Under high pressure, the material is less likely to extrude into clearance gaps, especially when used with proper backup rings or anti-extrusion devices. For dynamic high-pressure seals, a PEEK loading of 20% to 25% is commonly recommended. The exact filler percentage should be matched to the specific pressure, surface finish, and media conditions for optimal performance.
Q: Does Kaxite Sealing offer custom machined PEEK filled PTFE components?
A: Yes, Kaxite Sealing specializes in custom machining of PEEK filled PTFE parts according to customer drawings or reverse-engineered samples. The manufacturing process includes material selection, compression molding or extrusion, CNC turning and milling, deburring, inspection, and packaging. Dimensional tolerances as tight as ±0.01 mm can be achieved on critical sealing surfaces. Small prototype runs and high-volume production are both supported. Customers can provide 2D drawings, 3D CAD models, or physical samples, and Kaxite Sealing will recommend the most suitable PEEK filler content, surface finish, and packaging for the application.
For detailed technical data, sample requests, or engineering support, contact Kaxite Sealing with your operating conditions and performance requirements. The company’s material specialists can help select the appropriate PEEK filled PTFE grade and component design for your sealing application.
