Kaxite Sealing manufactures expanded PTFE (ePTFE) gaskets from 100% virgin PTFE with a microporous node-and-fibril structure. Soft, highly compressible and creep-resistant — they seal rough, pitted, warped and glass-lined flanges where solid PTFE and compressed fibre gaskets fail. We die-cut, CNC-machine, laminate and envelope in thicknesses 0.5–3.0 mm, density 0.7–1.2 g/cm³, service range -240 to +260 °C. Procurement teams choose us for factory-direct bulk pricing, documented traceability and 5–7 day lead times.
The microporous ePTFE structure flows into grooves, scratches, pitting and warping that rigid PTFE cannot bridge. Restores sealing integrity on legacy, glass-lined and enamel flanges without machining or flange replacement.
Stress relaxation below 20% (ASTM F38) with compression set 30–50% (ASTM F36). Combined with high recovery, bolted joints stay tight through thermal cycling, vibration and differential flange expansion — no repeated re-torquing.
100% virgin PTFE with no fillers, binders or plasticisers. Inert to strong acids, bases, solvents and oxidising agents. Compliant with FDA 21 CFR 177.1550 and USP Class VI for food and pharmaceutical service.
Resin, expansion, lamination, die-cutting and CNC machining all run inside our Ningbo plant. No trading layer, so your ePTFE gasket price stays stable even on repeat bulk orders.
Sheet stock for on-site cutting, precision die-cut gaskets to ANSI/DIN/JIS flanges, laminated tape for uneven flanges, and ePTFE envelopes for spiral-wound constructions. Send a drawing — we return custom ePTFE gaskets.
Batch records, density and tensile test reports, plus full resin-lot traceability from PTFE to finished gasket. Third-party testing (SGS, TÜV) on request. Pre-shipment photo verification on bulk orders.
Die-cut, CNC-machined or laminated from 100% virgin expanded PTFE. The microporous structure conforms to irregular and slightly damaged flange surfaces, providing effective sealing at lower bolt loads than solid PTFE. Available as flat sheet gaskets, laminated tape wraps, envelopes for spiral-wound constructions, or custom shapes to drawing. Density 0.7–1.2 g/cm³, thickness 0.5–3.0 mm, service range -240 to +260 °C, pH 0–14. Non-flammable and self-extinguishing (ASTM F202).
| Property | Test Standard | Typical Value | What It Means for You |
|---|---|---|---|
| Specific Gravity | ASTM D792 | 0.7 – 1.2 g/cm³ | Lower density = higher compressibility and conformability |
| Tensile Strength (MD) | ASTM D638 | 15 – 25 MPa | Withstands handling and installation without tearing |
| Elongation at Break | ASTM D638 | 100 – 300 % | Highly flexible, stretches without damage |
| Compression Set | ASTM F36 (22 h @ 25 °C) | 30 – 50 % | Good recovery for long-term seal retention |
| Stress Relaxation | ASTM F38 | < 20 % | Maintains bolt load over years of service |
| Thermal Conductivity | ASTM C518 | ~ 0.25 W/m·K | Provides thermal insulation between flanges |
| Service Temperature | — | -240 to +260 °C | From cryogenic LNG to process steam |
| pH Range | — | 0 – 14 | Full acid-to-alkali chemical inertness |
| Fire Safety | ASTM F202 | Non-flammable, self-extinguishing | Approved for fire-risk service |
MOQ negotiable for trial and prototype orders. Free cut samples of standard thickness and density available for material evaluation.
5–7 business days for custom die-cut and CNC-machined gaskets from stock sheet. Longer for molded or special constructions.
FOB Ningbo / Shanghai, CIF and DDP available. T/T and L/C terms confirmed at quotation. Flat-packed cartons or pallets for bulk orders.
Inspection report with every shipment. FDA 21 CFR 177.1550, USP Class VI, RoHS and REACH declarations with full resin-lot traceability.
Filled PTFE is virgin PTFE blended with glass, carbon or bronze to improve creep resistance or hardness — but fillers can reduce pure chemical inertness. ePTFE is 100% virgin PTFE that is mechanically stretched into a microporous structure. This gives ePTFE superior conformability, lower sealing stress requirements and better flexibility without compromising chemical resistance. For sealing uneven or damaged flanges, ePTFE is generally the better choice.
Yes — this is one of their key strengths. The soft, fibrous structure conforms to and fills surface imperfections that cause leaks with harder, more rigid gasket materials. For heavily damaged flanges, we often recommend a slightly thicker ePTFE sheet or a laminated tape wrap to ensure adequate material bridges the gaps. That said, for long-term reliability flange repair or replacement is always preferred where possible.
Installation torque depends on flange material (soft cast iron vs. hard steel), surface finish, gasket thickness and bolt size. As a general guideline for standard raised-face flanges we recommend a target compressive stress on the gasket face of 10,000 to 15,000 psi, typically achieved with standard ASME bolt torque values. Always follow a star-pattern tightening sequence in multiple passes to achieve even compression.
ePTFE is resistant to virtually all industrial chemicals — strong acids, strong bases, solvents and oxidising agents. The only known exceptions are molten alkali metals (sodium, potassium), certain fluorine compounds, and fluorine gas at elevated temperature and pressure. For 99% of industrial applications ePTFE provides unmatched chemical compatibility.
Thickness selection balances flange condition, pressure and gap-filling needs. Standard smooth flanges in standard pressure service: 1.5 mm is common. Low-pressure or delicate flanges: 0.8 or 1.0 mm may be suitable. Uneven, scratched or warped flanges: 2.0 or 3.0 mm provides more material to conform and fill voids. Higher pressure service also benefits from optimised thickness to manage creep.
Yes. Our ePTFE gaskets are manufactured from 100% virgin PTFE resin that complies with FDA 21 CFR 177.1550 for food contact and is certified to USP Class VI for biocompatibility. They are also suitable for potable water service. They do not leach contaminants and are tasteless and odourless, making them ideal for sanitary processing, biotechnology and food & beverage industries.
ePTFE has an exceptionally long, virtually indefinite shelf life when stored properly. Unlike elastomers it is not susceptible to degradation by moisture, oxidation or UV light. Store gaskets in a cool, dry place away from direct sunlight and extreme heat, keep them in their original packaging until use, and avoid stacking heavy objects on top of sheets or gaskets to prevent permanent deformation.
Yes. Our CNC and die-cutting capabilities allow integrated features such as alignment ears, bolt-hole cutouts to ANSI/DIN/JIS patterns, and any custom outer profile from your drawing. We also supply laminated tape wraps for on-site application on large or irregular flanges, and ePTFE envelopes for spiral-wound gasket constructions.
Send us your flange standard, gasket ID/OD, thickness, density grade, quantity or finished-part drawing. Our export team replies within 24 hours and confirms lead time, packaging and documentation before you place a bulk order.
