IDT UNIFLUOR 7551 Gasket VS Garlock Gylon 3500 Gasket
author: www.qishine.com
2026-06-05
I. Introduction
IDT UNIFLUOR-7551 gaskets and Garlock Gylon 3500 gaskets are similar in appearance. Both are based on biaxially oriented PTFE filled with silica, and both address cold flow, resist extreme temperatures, and withstand highly corrosive media. So, from a purely material performance perspective, what exactly are the differences between them?
IDT UNIFLUOR-7551 gaskets and Garlock Gylon 3500 gaskets are similar in appearance. Both are based on biaxially oriented PTFE filled with silica, and both address cold flow, resist extreme temperatures, and withstand highly corrosive media. So, from a purely material performance perspective, what exactly are the differences between them?
II. Product Background and Core Differences
1. IDT UNIFLUOR 7551
A high-grade biaxially oriented PTFE-based sealing material filled with silica. It offers excellent chemical resistance, good mechanical strength, and improved resistance to cold flow. It provides universal sealing performance across the entire pH range, and is particularly suitable for strong acids (except hydrofluoric acid), as well as other media such as fuels, steam, and chlorine.
1. IDT UNIFLUOR 7551
A high-grade biaxially oriented PTFE-based sealing material filled with silica. It offers excellent chemical resistance, good mechanical strength, and improved resistance to cold flow. It provides universal sealing performance across the entire pH range, and is particularly suitable for strong acids (except hydrofluoric acid), as well as other media such as fuels, steam, and chlorine.
Unifluor 7551 Gasket: a high-end biaxially oriented ptfe-based sealing material filled with silica
It is a non-asbestos, environmentally friendly sealing material suitable for temperatures from -200°C to +250°C and pressures up to 80 bar. The product holds FDA, BAM (German Federal Institute for Materials Research), and Germanischer Lloyd certifications, covering applications in cryogenic temperatures, highly corrosive media, and high-purity oxygen.
Widely used in petrochemicals, pharmaceuticals and food, shipbuilding, power plants, air separation, cryogenic media, and high-risk media.
2. Garlock Gylon 3500
Gylon 3500 is made from modified PTFE and silica filler through a unique compression molding process. Its key advantage is that the silica filling completely resolves the cold flow issue of traditional PTFE, maintaining stable torque after bolt tightening. It supports a wide temperature range from -268°C to +250°C (short-term up to 260°C) and a maximum working pressure of 1200 PSI (approx. 83 bar). It is suitable for strong acids (except hydrofluoric acid), solvents, hydrocarbons, steam, chlorine, and other aggressive media.
Gylon 3500 is made from modified PTFE and silica filler through a unique compression molding process. Its key advantage is that the silica filling completely resolves the cold flow issue of traditional PTFE, maintaining stable torque after bolt tightening. It supports a wide temperature range from -268°C to +250°C (short-term up to 260°C) and a maximum working pressure of 1200 PSI (approx. 83 bar). It is suitable for strong acids (except hydrofluoric acid), solvents, hydrocarbons, steam, chlorine, and other aggressive media.
Gylon 3500 Gasket: Modified PTFE + Silica Filler
III. Comprehensive Comparison: Composition, Process, and Engineering Performance
| Comparison Aspect | IDT UNIFLUOR® 7551 | Garlock Gylon 3500 |
| Product Type | High-performance sealing gasket (flat gasket) | High-performance sealing gasket (sheet/die-cut) |
| Material Composition | Modified PTFE + silica filler | Modified PTFE + silica filler |
| Manufacturing Process | Biaxial orientation | Compression molding |
| Color | Light tan / beige | Tan |
| Temperature Range | -200°C to +260°C | -268°C to +250°C |
| Max Pressure | 80 bar (for 2mm thickness) | Approx. 83 bar (1200 PSI, for 1.6mm thickness) |
| Cold Flow Resistance | Excellent | Excellent (industry benchmark) |
| FDA Certification | Yes | Yes |
| Cryogenic Suitability | Excellent (supports -200°C) | Excellent (supports -268°C) |
| Special Certifications | BAM (oxygen/ethylene oxide), Germanischer Lloyd | ABS (American Bureau of Shipping), USDA |
| Typical Applications | Steam, hydrocarbons, strong acids, cryogenic media, oxygen | Strong acids, solvents, chlorine, steam, cryogenic media |
Unifluor 7551 Gasket vs Gylon 3500 Gasket
IV. Engineering Application Recommendations and Selection Guide
When deciding between IDT 7551 and Gylon 3500, consider the following three dimensions:
When deciding between IDT 7551 and Gylon 3500, consider the following three dimensions:
Temperature Limits
- Cryogenic limits (-200°C to -268°C): Both are suitable for cryogenic service. If your media is liquid hydrogen (-253°C) or liquid helium, Gylon 3500’s -268°C lower limit offers an advantage. For liquid nitrogen (-196°C) or LNG (-162°C), IDT 7551’s -200°C is fully sufficient.
- Cryogenic limits (-200°C to -268°C): Both are suitable for cryogenic service. If your media is liquid hydrogen (-253°C) or liquid helium, Gylon 3500’s -268°C lower limit offers an advantage. For liquid nitrogen (-196°C) or LNG (-162°C), IDT 7551’s -200°C is fully sufficient.
- High-temperature limits: IDT 7551 has a recommended continuous operating temperature of 200°C, with short-term capability up to 260°C. Gylon 3500 has a continuous operating limit of 250°C. Both have comparable performance in high-temperature ranges, with little practical difference.
Pressure and Safety
- IDT 7551 has a maximum pressure of 80 bar, while Gylon 3500 is rated at 83 bar — essentially identical.
- Special certifications: IDT 7551 holds BAM certification. For applications involving high-purity oxygen, ethylene oxide, or other explosive media, choosing a BAM-certified product is safer and more compliant.
- IDT 7551 has a maximum pressure of 80 bar, while Gylon 3500 is rated at 83 bar — essentially identical.
- Special certifications: IDT 7551 holds BAM certification. For applications involving high-purity oxygen, ethylene oxide, or other explosive media, choosing a BAM-certified product is safer and more compliant.
Chemical Resistance and Certifications
- Hydrofluoric acid (HF): Because both materials contain silica (SiO₂), neither is resistant to HF. If the medium contains HF, alternative materials (such as pure PTFE or carbon‑fiber‑filled gaskets) should be used.
- Food and pharmaceutical: Both have FDA certification and can be used in food contact. Gylon 3500 has a longer history and deeper data accumulation in the pharmaceutical industry.
- Hydrofluoric acid (HF): Because both materials contain silica (SiO₂), neither is resistant to HF. If the medium contains HF, alternative materials (such as pure PTFE or carbon‑fiber‑filled gaskets) should be used.
- Food and pharmaceutical: Both have FDA certification and can be used in food contact. Gylon 3500 has a longer history and deeper data accumulation in the pharmaceutical industry.
V. Summary
In industrial projects, IDT UNIFLUOR-7551 acts as a “system engineer” for electrochemical protection of pipelines. Its complete kit design ensures full isolation of the flange circuit, making it a faithful guardian of cathodic protection systems. Garlock Gylon 3500, on the other hand, is a “sealing guard” for demanding sealing applications. Its wide temperature range, cold flow resistance, strong corrosion resistance, and FDA certification make it irreplaceable in chemical, food, cryogenic, and many other harsh environments.
In industrial projects, IDT UNIFLUOR-7551 acts as a “system engineer” for electrochemical protection of pipelines. Its complete kit design ensures full isolation of the flange circuit, making it a faithful guardian of cathodic protection systems. Garlock Gylon 3500, on the other hand, is a “sealing guard” for demanding sealing applications. Its wide temperature range, cold flow resistance, strong corrosion resistance, and FDA certification make it irreplaceable in chemical, food, cryogenic, and many other harsh environments.
Qishine is ideal choice for EPC companies and project contractors.
Website: www.qishine.com
Email: qishine@qishine.com
Tel: 0592-5225595
WhatsApp: +86 15960259563
+86 15985833169
Website: www.qishine.com
Email: qishine@qishine.com
Tel: 0592-5225595
WhatsApp: +86 15960259563
+86 15985833169
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