Polyoxymethylene (POM), also known as acetal resin, polyacetal, or polyformaldehyde, is a thermoplastic crystalline polymer. Referred to as "super steel" or "sai steel," POM is another engineering plastic with excellent comprehensive properties, following polyamide (nylon). It was first synthesized by DuPont in the United States around 1955 through the polymerization of formaldehyde. POM exhibits high mechanical properties such as strength, modulus, wear resistance, toughness, fatigue resistance, and creep resistance, along with excellent electrical insulation, solvent resistance, and processability.
POM is a linear polymer without side chains, featuring high density and high crystallinity, which grants it outstanding overall performance. It appears pale yellow or white with a smooth, glossy, hard, and dense surface, and can be used continuously within a temperature range of -40°C to 100°C.
POM’s wear resistance and self-lubricating properties are superior to most engineering plastics. It also has good resistance to oils and peroxides, but is not resistant to acids, strong alkalis, or UV radiation from sunlight.
POM has a tensile strength of up to 70 MPa, low water absorption, and good dimensional stability—properties that outperform nylon. Additionally, POM’s high crystallinity provides excellent solvent resistance. Its molecular weight typically ranges from 20,000 to 110,000. The melt has low elasticity and low strength, which may limit its use in some blow molding applications. However, POM crystallizes very quickly, with post-molding shrinkage completing within 48 hours, making it ideal for manufacturing parts requiring fast curing.
POM sealing rings are widely used in various industries due to their excellent physical and chemical properties. The main application sectors are as follows:
Automotive Industry
POM sealing rings play a vital role in the automotive sector. They are used for sealing key components such as automotive pumps, carburetor parts, fuel lines, power valves, universal joint bearings, motor gears, and crankshafts. The high wear resistance and self-lubricating properties of POM sealing rings enable them to operate stably in automotive engines and transmission systems for extended periods, reducing friction and wear, and improving vehicle performance and reliability.
Mechanical Industry
In the mechanical industry, POM sealing rings are widely used in the manufacturing of transmission components such as bearings, gears, and cams, as well as sealing elements like gaskets and oil seals. POM’s high load-bearing capacity and self-lubricating characteristics make it an ideal material for mechanical parts. It can withstand heavy loads and high-speed operation, ensuring the normal operation and extending the service life of mechanical equipment.
Electronics Industry
POM sealing rings are also widely used in the electronics industry. Due to POM’s excellent electrical insulation and processability, they are often used to seal electrical insulators, sockets, switches, connectors, and other electronic components. POM sealing rings ensure the reliability of electrical connections and signal transmission in electronic devices, while preventing interference from external factors such as dust and moisture.
Chemical Industry
In the chemical industry, POM sealing rings are used to manufacture corrosion-resistant pipeline components, pump parts, valves, and more. POM’s chemical resistance allows it to withstand the attack of various chemical substances, ensuring the normal operation and safety of chemical equipment.
Medical Devices
POM sealing rings also find applications in medical device manufacturing. Due to their good biocompatibility and corrosion resistance, they are used to seal various medical equipment such as syringes, infusion sets, and hemodialysis machines. POM sealing rings ensure the sealing performance and safety of medical devices, protecting patients’ health and safety.
Other Industries
In addition to the above sectors, POM sealing rings are widely used in consumer goods such as home appliances, household products, toys, zippers, and mascara wands. POM’s wear resistance, self-lubricating properties, and chemical resistance make it an indispensable sealing material in these products.
In conclusion, polyoxymethylene (POM) material and its derived sealing rings play an important role in multiple industries thanks to their excellent physical and chemical properties.