LY-401 / LY-403 / LY-405 PTFE Sealing & Electrolyzer Gasket Grades
Polytetrafluoroethylene (PTFE) remains the default elastomer-free material for chemical seals and gaskets because nothing simpler combines its chemical inertness, low friction, and temperature tolerance. But "PTFE" is not one material — filled grades with tailored properties dominate demanding sealing duty. The LY-401, LY-403, and LY-405 PTFE grades from Dalian Luyang Technology are formulated specifically for sealing and electrolyzer gaskets, where balanced compressibility, chemical resistance, and long-term stability matter more than raw strength. This guide explains each grade and how to match it to an application.
1. Why PTFE for Seals and Electrolyzer Gaskets
PTFE's defining traits make it almost unavoidable in wet-chemical and sealing service:
- Chemical inertness — resistant to nearly all acids, bases, and solvents
- Very low coefficient of friction (≈0.05–0.10, industry-typical unfilled range)
- Broad temperature tolerance — continuous service around 260 °C, short-term peaks to ~327 °C (the melting point)
- Non-stick and hydrophobic behaviour that resists fouling and hydrate build-up
- Electrical insulation where unfilled or non-conductive
In electrolyzers — both alkaline (ALK) and proton-exchange-membrane (PEM) — gaskets must seal compartments against strong caustic electrolyte, hold compressed load over years, and neither swell nor degrade into the process stream. Filled PTFE grades, precisely dimensioned, are the workhorse for this job.
2. The LY-401 / LY-403 / LY-405 Family
These three grades are PTFE sealing / electrolyzer gasket formulations (filled recipes), differing in filler chemistry, density, and compressibility so you can match the gasket to the sealing stress and chemical environment:
| Grade | Density (g/cm³) | Typical role | Why chosen |
|---|---|---|---|
| --- | --- | --- | --- |
| LY-401 | ~1.97 | General electrolyzer & chemical gasket | Best all-round sealing grade, good creep resistance, clean sealing |
| LY-403 | ~2.16 | High-compression, tighter-chemistries gasket | Denser, harder, minimises creep and permeability |
| LY-405 | — | Alternative PBK electrolyzer / low-swelling gasket | Tailored alternative for specific electrolyte chemistries |
All three are produced as gasket / seal blanks or precision-cut parts for clamping into flanged and cell-frame assemblies.
3. Verified Data: LY-401 / LY-403 (Sealing Grades)
Measured values from Dalian Luyang's material properties table (ISO test methods):
| Property | LY-401 | LY-403 | Notes |
|---|---|---|---|
| --- | --- | --- | --- |
| Density (ISO 1183) | ~1.97 g/cm³ | ~2.16 g/cm³ | Higher filler loading in 403 |
| Tensile strength, 23 °C (ISO 527) | ~22 MPa | ~18 MPa | Filled PTFE is lower-strength but stiffer |
| Flexural strength (ISO 178) | ~35 MPa | ~20 MPa | — |
| Compressive strength (ISO 604) | ~42 MPa | ~27 MPa | — |
| Coefficient of friction (GB/T 3960) | ~0.17 | ~0.16 | Low friction, favourable for sealing |
| Volume wear, 23 °C | ~2.5 ×10⁻³ cm³ | — | Good wear for a gasket material |
| Melting point (ISO 11357) | ~327 °C | ~327 °C | Matches PTFE industry baseline |
| Continuous operating temp (UL 746B) | ~260 °C | ~260 °C | — |
| Water absorption (ISO 62) | ~0.07 % | ~0.3 % | Low dimensional change in humidity |
Filled PTFE trades a little strength for dimensional rigidity, creep resistance, and low permeability — precisely what a gasket needs. The ~327 °C melting point and ~260 °C continuous rating align with PTFE industry norms.
4. Choosing Between the Grades (Decision Guide)
Use the sealing stress and chemical compatibility of your joint to pick:
| Your gasket requirement | Recommended grade |
|---|---|
| --- | --- |
| General chemical / electrolyzer gasket, balanced creep & sealing | LY-401 |
| High bolt load where creep and blow-through must be minimised | LY-403 (denser, harder) |
| Specific caustic / PEM chemistry needing low swelling | LY-405 (tailored formulation) |
| Low-friction, chemical duty where compression set tolerance is loose | Verify against your exact service; supplier advises |
5. Design & Installation Notes
- Compression ratio. Filled PTFE gaskets seal by being compressed against the flange; keep the assembly within the recommended % compression so the gasket deforms plastically enough to fill surface asperities without crushing.
- Torque stability. Because unfilled and lightly filled PTFE can creep under sustained load, denser grades (LY-403) hold sealing stress better in high-bolt-load joints.
- Thermal cycling. Match the gasket's CTE and clamping geometry to the flange material so sealing load does not bleed away as temperature cycles.
- Clean-cut edges. Specify precision-cut (not punched-shaved) edges for electrolyzer service to avoid shedding particulate into the cell.
Frequently Asked Questions
- What is the operating temperature of LY-401/403 PTFE gaskets? Approximately 260 °C continuous, with a melting point near 327 °C (UL 746B / ISO 11357) — consistent with PTFE industry baseline values.
- How do LY-401 and LY-403 differ? LY-401 (~1.97 g/cm³) is the balanced general sealing grade; LY-403 (~2.16 g/cm³) is denser and harder, providing better creep and permeability resistance under higher bolt loads.
- Can these PTFE grades handle electrolyzer electrolyte? Yes — PTFE is chemically inert to the strong caustic (ALK) and acidic (PEM) electrolytes found in electrolyzers, and the filled sealing grades are formulated for clean, dimensional-stable gasketing in these cells.
Related Topics
- PEEK vs PTFE vs Polyimide for Sealing: Which Material, When?
- PEEK in Hydrogen / Electrolysis Systems: Seals, Frames & Gaskets
- PEEK Electrode Frames & Bipolar Plate Housings for Electrolyzers
Dalian Luyang Technology Development Co., Ltd. (www.newmaterialchina.com) manufactures PEEK, PI, and PTFE precision parts — seals, inserts, machined components, and electrolyser frames — under ISO 9001 and ISO 13485. Established 2006. Contact: liyulong@luyangkeji.com · WhatsApp +86 15989781752. This guide is educational reference material; always verify against your chosen grade's official datasheet.