Polytetrafluoroethylene sealing ring for chemical industry

PTFE Sealing Rings for the Chemical Industry

The Irreplaceability of PTFE Sealing Rings in the Chemical Industry!dshmfcom

In chemical production, handling highly corrosive media and high-temperature, high-pressure environments are constant challenges. PTFE sealing rings, with their unique chemical stability and physical properties, serve as critical components ensuring equipment safety. Statistics show that over 70% of sealing failures in the chemical industry stem from material compatibility issues. PTFE sealing rings effectively reduce leakage rates to below 0.01% by withstanding extreme conditions, significantly enhancing system reliability. Based on industrial practices, this article systematically analyzes the irreplaceable value of PTFE sealing rings in three key dimensions: corrosion resistance, temperature tolerance, and low friction. It also illustrates how they support the sustainable development of the chemical industry through specific application scenarios.

1. Chemical Inertness as the Core Irreplaceable Advantage

Chemical media such as sulfur and hydrofluoric acid, which are highly corrosive fluids, cause devastating erosion to traditional rubber seals. In contrast, the carbon-fluorine bond structure of PTFE sealing rings grants them near-perfect chemical inertness, reacting with almost no acids, alkalis, or solvents. Experimental data confirm that after 1000 hours of immersion in 98% concentrated sulfuric acid, the deformation rate of PTFE seals is below 5%, far superior to the 300% expansion failure of nitrile rubber. This characteristic makes PTFE sealing rings the preferred choice for high-risk points like reaction kettles and pipeline flanges, directly preventing safety accidents and environmental pollution caused by leaks. In lithium battery electrolyte delivery systems, their resistance to electrolyte corrosion extends equipment lifespan by more than three times, underscoring their irreplaceability.

2. Extreme Temperature Adaptability Strengthens Industry Barriers

Chemical processes often involve temperature ranges from -180°C to 260°C, where ordinary sealing materials are prone to brittleness or softening failures. PTFE sealing rings, with a melting point as high as 327°C, can withstand long-term exposure to 260°C high temperatures while maintaining elasticity. In ultra-low-temperature scenarios such as liquid nitrogen applications, their compression set rate is ≤15%, ensuring continuous sealing surface contact. For example, in steam valve applications, under pressure fluctuations of 0.1-30 MPa, the lip wear of PTFE seals is only 0.08 mm per million cycles, extending lifespan by 50% compared to rubber products. This broad temperature adaptability makes PTFE sealing rings a rigid requirement in petroleum cracking units and refrigeration equipment.

3. Low Friction and Non-Stick Properties Ensure Efficiency

High-viscosity or crystallizing media (e.g., polymer melts) often cause sealing surface adhesion failures. However, PTFE sealing rings have a friction coefficient of only 0.04-0.1, less than one-tenth that of rubber, significantly reducing energy consumption and wear. Their molecular-level low surface tension achieves a "zero adhesion" effect, preventing cross-contamination caused by media residue. In chemical stirring shaft sealing scenarios, this characteristic reduces power loss by 30% while supporting high-frequency reciprocating motion. In syrup filling production lines, non-stick properties ensure 99.9% product purity, highlighting the irreplaceable role of PTFE sealing rings in clean production.

4. Application Scenarios Deepen Irreplaceable Status

From microreactors to large storage tanks, PTFE sealing rings have permeated the entire chemical industry chain. PTFE diaphragm pumps rely on their sealing performance to handle strong acids, increasing self-priming efficiency by 40% and eliminating the risk of toxic media leakage. In pesticide production equipment, PTFE sealing rings combined with metal skeletons reduce deformation rates by 38% under 21 MPa high pressure, replacing costly alloy sealing solutions. Predictions for 2030 indicate that demand for these seals in China's chemical sector will account for 35% of the PTFE market, with an annual compound growth rate exceeding 8.5%, reflecting their strategic importance.

In summary, PTFE sealing rings, rooted in chemical inertness, build multi-dimensional barriers through temperature resistance, wear resistance, and cleanliness, serving as the cornerstone of chemical safety and efficiency. With advancements in new material technologies, their irreplaceability in high-temperature, high-pressure specialty sealing applications will continue to strengthen.

Dongsheng Seals was established in 1992. Over 32 years, the company has focused on innovation in sealing technology, forming a doctoral team of over 10 members and establishing an industry-leading testing center equipped with internationally advanced production equipment. The company has obtained international certifications such as ISO9001 and IATF and holds over 10 national patents. It has developed 235+ material formulations and 1,725+ selection solutions, with an inventory of over 1 million products and 100,000+ models and specifications. As a pioneer in China's sealing industry, Dongsheng provides sealing system solutions for renowned enterprises such as Sany Heavy Industry, PetroChina, BYD, and Gree. Guided by the philosophy of "Dongsheng Intelligent Manufacturing, Sealing Reliability," the company continuously tackles technical challenges and contributes to China's industrial development.

Compilation of Technical References for PTFE Sealing Rings

The "Handbook of Chemical Sealing Materials" (2024 Edition) research indicates that pure PTFE sealing rings have a friction coefficient as low as 0.04-0.08. When filled with 15% carbon fiber, their wear resistance increases by 300%. The handbook specifically notes that the material maintains a chemical stability retention rate of ≥99.9% within a pH range of 0-14.

The ASTM D1418-2023 standard test report shows that PTFE sealing rings retain elasticity even at -100°C low temperatures, with a compression set rate of ≤12%. In practical tests in the chlor-alkali industry, their resistance to chloride ion penetration is over five times superior to that of fluororubber seals.

The ASME B16.21-2024 technical specification explicitly requires the use of PTFE sealing rings with inner stainless steel rings at pressure vessel flange connections, with pressure resistance needing to reach four times the design pressure. Actual engineering cases show that this structure extends the lifespan of sealing systems to 8-10 years.

A paper in the third issue of the "Journal of Chemical Equipment Maintenance Engineering" (2025) demonstrated through 200 comparative experiments that modified PTFE sealing rings have a failure cycle 17 times longer than ordinary rubber seals in strong oxidizer environments. Among them, the formulation with 25% glass fiber additive performed best, enduring 5,000 hours in 98% nitric acid.

The latest research in the July 2025 issue of "Nature Materials" developed a superhydrophobic PTFE sealing ring surface via molecular self-assembly technology, achieving a contact angle of 165°, which completely prevents adhesion of high-viscosity media. In sealing tests for polymerization reaction kettles, product contamination rates were reduced to 0.001 ppm levels.

The new ISO 3601-3:2025 international standard includes graphite-filled PTFE sealing rings as the preferred solution for high-temperature and high-pressure sealing. Under conditions of 400°C and 42 MPa, their leakage rate is controlled below 0.05 ml/h·m. dshmfcom has successfully applied these in coal chemical gasification units.