PEEK Vs. PTFE In The Sealing Industry

PEEK Sealing Ring/PEEK Seal Ring Overview

PEEK sealing ring has good performance, stable size, specification size can be customized, high temperature resistance, abrasion resistance and strong mechanical properties. High temperature resistant PEEK has a high glass transition temperature and melting point (334°C), which is one of the reasons it can be reliably used in applications where heat resistance is required. It has a loaded thermal transition temperature of up to 316°C and a continuous use temperature of 260°C. PEEK in high-performance polymers with other general-purpose plastics can not be compared to the comprehensive performance, with a variety of harsh environments applicable to the performance, has been successfully and widely used in aerospace, automotive, electronic semiconductors, electromechanical and other industries in the requirements of the more demanding occasions. It is the user to carry out new product development, improve product life and reliability of materials.

PEEK main characteristics and advantages

1: High temperature UL certification for long-term use of 260 ℃. Even at temperatures as high as 316 ℃, can still maintain good mechanical properties.

2: Wear-resistant in many high temperature, high load, strong corrosion and other extremely harsh application environment, PEEK polymer and its composite materials have good wear resistance.

3: Self-lubricating with a low coefficient of friction, can be realized without oil lubrication work, can be in oil, water, steam, weak acids and alkalis and other media in the long-term work.

4: Corrosion resistance is insoluble in common solvents, a variety of organic and inorganic chemical reagents, have good corrosion resistance.

5: High strength in plastics with good mechanical strength. It also has high rigidity and surface hardness.

6: Easy to process can be directly processed using the injection molding process to produce parts. Can be turned, milling, drilling, tapping, bonding and ultrasonic welding and other post-processing.

7: Hydrolysis resistance at a temperature of more than 250 ℃ steam or in high pressure water immersion, PEEK products can still work continuously for thousands of hours without significant performance degradation.

8: Flame retardant in the absence of additives, 1.45 mm thickness of PEEK samples of flammability grade UL94V-0.

9: Low smoke and non-toxicity The amount of smoke and poisonous gas is particularly low when burning.

10: Electrical properties in a wide range of temperatures and frequencies, can still maintain a stable, excellent electrical properties.

11: Radiation resistance has a strong resistance to high doses of γ-ray radiation, mechanical properties can be retained intact, can be used as nuclear equipment in the radiation parts.

12: Dimensional stability

PEEK application in automotive seals

One of the main applications of PEEK in automotive manufacturing is the development of seals for use in internal combustion engines. The sealing rings used in engines are critical because they prevent fluids from leaking and contaminants from entering sensitive engine components. The sealing rings must withstand the extreme temperatures generated by combustion while maintaining their shape and sealing ability. PEEK-based seals have been found to have excellent leakage stability at high temperatures, making them ideal for sealing rings in internal combustion engines. In addition, PEEK-based seals have a low coefficient of friction, which helps reduce energy consumption during operation.

PEEK in Automotive Cylinder Head gaskets

Another application is the development of cylinder head gaskets, which require good heat and wear resistance due to their proximity to hot engine components such as cylinders and exhaust systems. Cylinder head gaskets must be able to withstand extreme temperatures without degrading or losing their ability to seal the different chambers within the engine block. A compound based on the combination of PEEK and Polytetrafluoroethylene (PTFE) has been developed specifically for cylinder head gasket applications, and good results have been achieved to date. The material has been found to have good heat, abrasion and tear resistance, as well as excellent replaceability.

The use of PEEK-PTFE compounds in cylinder head gaskets eliminates the risk of contact corrosion, which is a significant problem when using traditional metal gaskets and can cause damage when they come into contact with other engine components. The benefits of using PEEK materials in automotive manufacturing are numerous and significant. For example, the use of seals and gaskets can help improve engine performance by reducing energy consumption through a lower coefficient of friction, and PEEK materials require less maintenance than traditional metal seals and are prone to corrosion and wear.

In summary, the use of high-temperature materials such as PEEK in automotive manufacturing represents a significant technological advancement with great potential to improve vehicle performance and reliability. PEEK-based seals and gaskets have been found to have excellent leakage stability at high temperatures, making them ideal for use in internal combustion engines. Cylinder head gaskets based on PEEK and polytetrafluoroethylene (PTFE) compounds have shown great promise because of their good heat, wear and tear resistance, as well as excellent replaceability.

What makes PEEK a sought-after material for the sealing industry?

As a polymer, PEEK is most often compared to PTFE. The two share a number of similarities, including good temperature resistance, chemical inertness and dielectric strength. However, in terms of pure physical strength, PEEK leads the way in two areas in particular.

First - the absolute strength of the material is much higher. PEEK has higher tensile strength and hardness, and outperforms PTFE in applications requiring dimensional stability over long periods of physical strain. While PTFE does contain fillers such as glass and carbon to increase stiffness, it does not match PEEK in this category.

Second - PEEK has a lower specific weight (1.35 vs. 2.25 for PTFE). Therefore, in applications where the total weight of the component needs to be minimized, PEEK is the winner. one of the applications where PEEK is highly sought after is in the sealing industry. The seals themselves comprise a wide range of polymers, elastomers and metals, each of which relies on the specific properties of the material used to achieve its application.

Types of PEEK seals

Piston ring seals: Piston rings are primarily used to help absorb wear on the outer diameter of the piston shaft. PEEK is hard enough to withstand the extensive wear caused within the piston, but not hard enough to damage the metal part itself. These rings are usually machined from PEEK bushings and have different types of cutouts to aid in installation and performance.

Ball valve seats: Ball valve seats show a major preference for PTFE because they require a soft material that yields easily to the shape of the ball valve. However, a large number of PEEK seats are used in high performance valves where both PTFE and metal are machined to ensure a proper fit. Typically, we see these materials used in valves on oil rigs or in power plants, where the high temperatures indicate the need for a slightly stiffer polymer than PTFE.

Rotary shaft seals: we have developed composite grades of PTFE and PEEK to meet the needs of the rotary shaft seal market. the combination of PTFE and PEEK is a powerful one. pTFE enhances self-lubricating properties while PEEK adds strength. Although they work well together, specific applications do require pure PEEK, which is intended to be used similarly to piston rings, with the exception of radial movement of the shaft. PEEK is again used to be able to withstand wear at high rotational speeds while being soft enough not to damage the metal in case of misalignment or seal failure.

Ball and Butterfly Valve Seats: A number of different materials are used in this application, including PTFE, Delrin and UHMWPE. PEEK is particularly well suited to high pressure and high temperature applications. Butterfly valves are an integral part of any fluid conditioning system, including hydroelectric power plants, oil and gas refineries, and shipping.

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