Silica-filled PTFE gaskets are made by adding silicon dioxide filler to PTFE resin through a specialized manufacturing process. Silica filling significantly improves PTFE's cold flow/creep behavior and bolt torque retention while maintaining PTFE's excellent chemical resistance.
These gaskets are ideal sealing materials for strong acids, solvents, hydrocarbons, chlorine, and cryogenic service.
|
Problem |
Consequences |
How Silica-Filled Gaskets Solve the Problem |
|
Creep and leakage of PTFE gaskets in strong acid service (sulfuric, hydrochloric, and nitric acids) |
Frequent replacement, production interruption, safety risks |
Silica-filled structure significantly reduces cold flow and improves bolt torque retention |
|
Frequent failure of seals in organic solvent pipelines |
Leakage, environmental pollution, product loss |
Silica-filled gaskets are resistant to most solvents |
|
Chlorine pipeline seals failing to meet standards, resulting in excessive fugitive emissions |
Environmental penalties, safety hazards |
TA-Luft (VDI 2440) certified; meets fugitive emission standards |
|
Embrittlement and leakage of conventional PTFE gaskets in cryogenic service (LNG, liquid oxygen) |
Seal failure, equipment downtime |
Suitable for temperatures as low as -268°C; designed for cryogenic applications |
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Product Form |
Description |
|
Sheets |
Standard size: 1500×1500mm; thicknesses: 1.6mm (1/16"), 3.2mm (1/8"), etc. |
|
Cut Gaskets |
Custom-cut to any flange size. |
Typical Color: Fawn, Brown
|
Comparison Item |
Silica-Filled |
BaSO₄-Filled |
Glass Microsphere Filling |
Glass Fiber-Filled |
|
Strong Acids (except HF) |
★★★★★ Best |
★★★★☆ Good |
★★★★☆ Good |
★★★★☆ Good |
|
Organic Solvents |
★★★★★ Best |
★★★★☆ Good |
★★★★☆ Good |
★★★★☆ Good |
|
Strong Caustics |
★★★☆☆ Moderate |
★★★★★ Best |
★★★☆☆ Limited |
★☆☆☆☆ Not suitable |
|
Hydrofluoric Acid (HF) |
❌ NOT compatible |
★★★★★ Suitable (up to 48%) |
❌ Not Compatible |
❌ NOT compatible |
|
Chlorine |
★★★★★ Excellent |
★★★★★ Excellent |
★★★★☆ Good |
★★★★☆ Good |
|
Cryogenic Service (-268°C) |
★★★★★ Best |
★★★★★ Best |
★★★★☆ Good |
★★★★☆ Good |
|
Creep Resistance |
★★★★★ Excellent |
★★★★★ Excellent |
★★★★☆ Good |
★★★★☆ Good |
|
Best Applications |
Strong Acids, Solvents, Chlorine, Cryogenic |
Caustics, HF |
Low Torque, Uneven Flanges |
High Wear, High Pressure |
Quick Decision:
Strong acids, solvents, chlorine, cryogenic → Choose Silica-Filled
Strong caustics, HF → Choose BaSO₄-Filled
Uneven flanges, low torque → Choose Glass Microsphere
High pressure, high wear → Choose Glass Fiber-Filled
|
Comparison Item / Comparison |
Silica-Filled PTFE Gasket |
Conventional PTFE Gasket |
Customer Value |
|
Creep Resistance |
★★★★★ Excellent (minimal cold flow) |
★★☆☆☆ Poor (significant cold flow) |
Bolts retain torque longer; seals last longer |
|
Bolt Torque Retention |
★★★★★ Excellent |
★★☆☆☆ Poor |
Reduced need for retightening; lower maintenance costs |
|
Strong Acid Resistance |
★★★★★ Excellent (except HF) |
★★★★★ Excellent |
Equally excellent performance |
|
Temperature Range |
-268°C to +260°C-268°C is the minimum rated limit for cryogenic service (liquid helium); continuous operating temperature depends on actual working pressure & flange condition. |
-200°C to +260°C |
Suitable for cryogenic conditions |
|
Max Pressure |
83 bar (1200 PSI) |
Lower |
Suitable for higher pressures |
|
Typical Seal Life |
3–5 years |
1–2 years |
2–3 times longer service life |
|
Material Cost |
30–50% higher |
(Lower) |
Lower total cost of ownership |
|
Advantages |
Description |
Customer Value |
|
Preferred for strong acid applications |
Excellent performance in corrosive media such as strong acids (except HF), solvents, and hydrocarbons |
Suitable for corrosive environments such as chemical and petrochemical processing |
|
Excellent creep resistance |
Minimized cold flow, significantly reduced creep relaxation, and excellent bolt torque retention |
Reduces the need for re-tightening and lowers maintenance frequency |
|
Suitable for cryogenic service |
Continuous use temperature: -200°C to +260°C. |
Suitable for cryogenic applications (e.g., LNG, liquid oxygen) |
|
High pressure rating |
Maximum pressure: 83 bar (1200 PSI) |
Compatible with higher-pressure-class flanges |
|
TA-Luft certified |
Complies with TA-Luft (VDI 2440) fugitive emission control requirements |
Environmentally compliant and audit-ready |
|
FDA compliant |
Complies with FDA 21 CFR 177.1550 and USDA requirements |
Suitable for the food and pharmaceutical industries |
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Parameter |
Parameter / Value |
|
Material |
PTFE + Silica (SiO₂) |
|
Color |
Fawn, Brown |
|
Density |
2.1–2.3 g/cm³ |
|
Minimum Temperature |
-268°C (-450°F) |
|
Maximum Temperature |
260°C (500°F) |
|
Maximum Pressure |
83 bar (1200 PSI) |
|
pH Range |
0–14 |
|
Gasket Factor (m) |
2.5 |
|
Max P×T (1/16") |
12,000 bar·°C |
|
Max P×T (1/8") |
8,600 bar·°C |
|
Sheet Size |
1500×1500mm, etc. |
|
Thickness Range |
1.6mm (1/16"), 3.2mm (1/8"), etc. |
⚠️ Not Suitable For:
❌ Hydrofluoric acid (HF) service — silica reacts with HF; use Barium Sulfate Gasket or virgin PTFE
❌ Strong caustics (NaOH, KOH) — use Barium Sulfate Gasket
|
Industry |
Typical Applications |
Key Requirements |
|
Chemical & Petrochemical |
Strong acid piping, solvent systems, hydrocarbon lines |
Resistance to strong acids and solvents |
|
Chlor-Alkali |
Chlorine piping seals |
Chlorine resistance |
|
Cryogenic Service |
LNG, liquid oxygen, cryogenic piping |
Low-temperature resistance down to -268°C |
|
Pharmaceutical |
Sterile equipment seals, clean piping |
FDA compliant |
|
Food & Beverage |
Food-grade piping seals |
FDA/USDA compliant |
|
Power Generation |
Steam systems, water treatment |
Temperature and pressure resistance |
|
Marine |
Marine piping flange seals |
ABS certification |
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Case Studies |
Challenge |
Solution |
Result |
|
Strong Acid Piping at a Chemical Plant in the USA |
Conventional PTFE gaskets creeping and leaking under concentrated sulfuric acid service, replaced every 8-12 months, annual maintenance >$20,000 |
Replaced with silica-filled PTFE gaskets |
3 years continuous service, zero leakage — maintenance cost reduced by 70% |
|
Solvent System at a Petrochemical Plant in Germany |
Solvent piping flanges leaking frequently, fugitive emissions exceeding limits, facing environmental fines |
Used silica-filled PTFE gaskets (TA-Luft VDI 2440 certified) |
TA-Luft certified, fugitive emissions compliance, passed environmental audit |
A: Silica-filled PTFE gaskets contain silica filler, significantly improved creep resistance (cold flow minimized), excellent bolt torque retention, wider temperature range ( -268°C to +260°C ), higher pressure rating ( 83 bar ).
Conventional PTFE gaskets have excellent chemical resistance but significant cold flow.
Choose silica-filled for: Strong acids, solvents, hydrocarbons, chlorine, cryogenic service.
Choose conventional PTFE for: General chemicals, non-critical applications. Silica-filled costs 30-50% more but offers 2-3x longer seal life, lower total cost.
A: The key difference is media compatibility.
Silica-filled gaskets perform better in strong acids and organic solvents, but are NOT compatible with hydrofluoric acid (HF) or strong caustics.
Barium sulfate-filled gaskets are compatible with HF (up to 48%) and strong caustics — the preferred choice for caustic and HF service.
Quick decision:
Strong acids, solvents, chlorine, cryogenic → Choose Silica-Filled.
Strong caustics, HF, toxic chemicals → Choose Barium Sulfate-Filled.
For specific selection advice, please provide your media, temperature, and pressure.
A: Yes. Silica-filled PTFE gaskets meet FDA 21 CFR 177.1550 and USDA food contact requirements.
PTFE is non-toxic, tasteless, odorless, and does not contaminate media. Please specify FDA-compliant grade when ordering.
A: Temperature: Continuous use temperature: -200°C to +260°C.
Pressure: Up to 83 bar (1200 PSI).
Chemical resistance: pH 0-14.
⚠️ NOT compatible with hydrofluoric acid (HF) or strong caustics.
For application-specific data, please provide your media, temperature, and pressure, we will calculate for you.
A: MOQ: Small-batch customization supported.
Lead time: Standard specifications 24-48 hours shipping; custom sizes 7-15 working days.
Samples: Free samples supported (available to both new and existing customers, shipping collect).
Payment terms: T/T (recommended).
Quality: Material certificates available for every batch.
Address
No.1028, Qiersan Street, Andong Town, Cixi City, Zhejiang Province, China
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