Delrin is the brand name for an acetal plastics, first developed and brought to market by DuPont in 1956. Delrin was commercially synthesized by DuPont, marking the transition from its discovery to large-scale commercial production.
It is highly regarded for its exceptional strength, wear resistance, and ease of machining. Delrin is valued for its versatility and suitability across a broad range of industries and applications.
So, what is Delrin? Why does it stand out among numerous materials? Delrin is considered an excellent material due to its superior properties, making it an outstanding choice for various demanding applications.
This article will delve into the characteristics of Delrin, its applications, and its significant role in the industry. We help you weigh up Delrin plastic as an alternative in your material selection.
Basic Definition Of Delrin
Delrin®, also known as polyoxymethylene (POM) or acetal homopolymer, is a semi-crystalline, engineering-grade thermoplastic widely used create highly precise parts.
Its molecular structure consists of repeating oxymethylene units (-CH₂O-), which endow it with high crystallinity and outstanding physical characteristics.
Because Delrin-made parts work well in moist or wet environments, it’s an excellent choice for products such as pump and valve components. In addition, it can be used for water management controls, faucets, and many kitchen appliances for similar reasons.
The origin of Delrin can be traced back to the American company DuPont. In the 1950s, DuPont pioneered the development and commercialization of this material, introducing the homopolymer version of POM under the registered trademark “Delrin.”
Delrin, stands out from other acetal plastics due to its unique semi-crystalline molecular structure. This uniform orientation provides enhanced stiffness and superior mechanical strength, making it a preferred choice for high-performance applications.
Material Properties Of Delrin
Delrin exhibits a wide operating temperature range, typically from -40°C to 120°C, allowing it to perform reliably in both lower temperatures and elevated temperatures without permanently deforming.
Its superior density contributes to its overall durability and mechanical strength, making it delrin ideal for parts exposed to demanding conditions.
In addition to its excellent mechanical properties, Delrin possesses outstanding chemical resistance, particularly against many chemicals and neutral chemicals, though it is less resistant to strong acids and oxidizing agents.
This chemical resistance helps prevent degradation and bacterial growth, which is crucial for applications in wet environments.
The thermal properties of Delrin, including its melting point around 175°C and good thermal stability during the cooling process, enable it to maintain dimensional stability and resist warping during manufacturing processes such as injection molding and extrusion.
Delrin’s plastic properties also include a low friction coefficient and high wear resistance, making it suitable for pump and valve components, fuel system components, and electrical insulator parts. Its resistance to corrosion further extends the lifespan of parts in harsh industrial applications.
Moreover, Delrin can be machined to create thin walls and complex shapes without compromising its strength, allowing for versatile design options in custom parts like knife handles and zip fasteners.
Overall, the combination of these material properties makes Delrin a highly reliable choice for a broad range of industrial, automotive, medical, and consumer goods applications.
Delrin Properties Table | |
|---|---|
Properties | Value |
Density（g/cm³） | 1.41 |
Melting Point(°C) | 175 |
Tensile Strength(MPa) | 70 |
Elongation at Break（%） | 25–40 |
Glass Transition Temperature(°C) | -60 |
Shrinkage Rate（%） | 1.8–2.2 |
Coefficient of Friction | 0.25 |
Advantage Of Delrin Material
Delrin serves as an excellent alternative for metal due to its wear resistance, high-tensile strength, low friction, and superior resistance to warping.
Delrin is ideal for applications that require high strength, stiffness, and resistance to moisture and chemicals, making it suitable for demanding industrial and mechanical environments.
Below are the primary benefits of Delrin plastic:
Superior Mechanical Properties
Delrin boasts high tensile strength (approximately 70 MPa), exceptional rigidity, and excellent fatigue resistance, with mechanical properties approaching those of certain metals.
This enables it to replace traditional metal components in the production of gear wheels, bearings, springs, and other parts requiring high strength and stiffness.
Excellent Dimensional Stability
Thanks to its high crystallinity and low water absorption, Delrin maintains high precision and shape stability under varying temperature and humidity conditions.
Its good dimensional stability makes it a preferred material in precision manufacturing, such as for instrument components and connectors.
High Wear Resistance
Delrin’s low friction coefficient and superior wear resistance make it excel in sliding or frictional applications.
It delivers long-term performance without the need for additional lubrication, an advantage that is particularly pronounced in formulations containing polytetrafluoroethylene (PTFE) lubricants (e.g., Delrin 500TL), making it ideal for high-wear scenarios.
Disadvantages Of Delrin Material
The drawbacks of Delrin primarily focus on its chemical resistance, thermal performance, and environmental adaptability, which limit its applications under extreme conditions.
Limited Heat Resistance
The long-term usage temperature of Delrin is typically between 80°C and 100°C. Although it can temporarily withstand up to 230°C after stabilization treatment, prolonged exposure to high temperatures can lead to performance degradation and even decomposition, releasing formaldehyde gas. This makes it unsuitable for continuous high-temperature applications.
Poor Flame Retardancy
Delrin’s flame retardancy is relatively weak, with a UL94 flammability rating of only HB (slow burning in horizontal testing). It is prone to burning and lacks self-extinguishing properties in environments with high fire risk. Therefore, other materials should be considered for applications requiring high fire resistance.
Tendency for Thermal Oxidative Aging
Under conditions where high temperatures and oxygen coexist, Delrin is prone to thermal oxidative aging, leading to brittleness or performance degradation. Although adding antioxidants can mitigate this issue, additional formulation optimization is needed to extend its service life.
Manufacturing Process Of Delrin Plastic
Delrin is one of the most popular manufacturing materials because of its unique combination of strength, durability, and versatility.
Compared to other plastics, Delrin stands out for its superior machinability and consistent performance in demanding environments, making it a preferred choice for many engineering applications.
The creation of Delrin parts involves several established manufacturing processes, each customized to meet the specific needs of the final product.Selecting the right plastic for each manufacturing process is crucial to ensure optimal performance and results.
Below is an overview of the primary methods and key considerations in the production of Delrin components.
Injection Molding
Delrin Injection molding is the most common method for producing delrin parts, especially for high-volume production of complex shapes.
This method allows for high precision, tight tolerances, and the ability to produce intricate geometries like gears, clips, and housings. Delrin’s low viscosity when molten ensures good flowability, making it ideal for detailed designs.
Due to Delrin’s high crystallinity (up to 70%), it exhibits a shrinkage rate of 1.8%–2.2%. Mold design must account for this to avoid dimensional inaccuracies.
Additionally, maintaining proper mold temperature (typically 80°C–100°C) and avoiding overheating (above 230°C) are critical to prevent decomposition, which can release formaldehyde gas.
CNC Machining
CNC machining is often employed for low volume production or to create high performance engineering components from extruded Delrin stock (e.g., rods or sheets).
Using computer-controlled tools, Delrin is cut, drilled, or milled into the desired shape. Common machined parts include bearings, valve components.
This process is ideal for producing custom parts with tight tolerances and complex geometries, ensuring excellent dimensional stability and surface finish.
Extrusion
Extrusion is used to create continuous shapes such as rods, sheets, or tubes, which can later be machined into final parts.
Extruded Delrin stock shapes are ideal for secondary machining processes, offering flexibility for custom parts like bushings or spacers.
Uniform cooling is essential to prevent internal stresses or warping due to Delrin’s high crystallinity. The extrusion process also requires careful temperature control to avoid thermal degradation.
Applications Of Delrin Plastic
Delrin’s applications span across industries such as industrial manufacturing, consumer goods, automotive, medical, and electronics, with its success attributed to its excellent balance of strength, wear resistance, and processability.
Examples of products that benefit from Delrin’s properties include food containers, medical instruments, and sports equipment, in addition to other consumer and industrial items.
Industrial Applications
Delrin is widely used in the industrial sector to manufacture parts requiring high precision and durability. Its low abrasion resistance and wear-resistant properties make it an ideal choice for gears, bearings, door systems, and pump components.
Consumer Goods
In consumer goods (6.0.2), Delrin is commonly used for zippers and fasteners. It is also widely utilized in the production of zip fasteners, where its durability and reliability make it ideal for manufacturing zippers, clips, and buckles in various consumer products.
Automotive Industry
In automotive manufacturing, Delrin’s lightweight nature and chemical resistance make it a preferred alternative to metal. It is commonly used in fuel system components, safety restraint devices, window regulator gears, and door lock mechanisms.
Additionally, Delrin is used in loudspeaker grilles for automotive and consumer audio systems, providing both durability and acoustically transparent properties essential for high-quality sound performance.
Electrical Insulation
Delrin’s insulating properties and dimensional stability make it an ideal material for connectors, switches, and electrical insulator parts in the electronics industry, maintaining performance across varying temperature and humidity conditions.
Delrin vs Nylon
Choosing the right material is crucial for ensuring product performance and durability in demanding environments.
Delrin and Nylon are both commonly used engineering plastics, but they have significant differences in moisture absorption and wear resistance.
Delrin has an extremely low moisture absorption rate (0.2%-0.5%), allowing it to maintain excellent dimensional stability in wet environments.
In contrast, Nylon has a higher moisture absorption rate (for example, Nylon 6 can absorb 1.5%-3%), which can lead to dimensional swelling and performance degradation after moisture absorption, potentially becoming an issue in high-precision applications.
Delrin has a lower coefficient of friction and higher wear resistance, particularly excelling in self-lubricating properties compared to Nylon. While Nylon also has some wear resistance, its higher friction coefficient makes it more prone to wear under high loads or unlubricated conditions.
Both Delrin and Nylon are resistant to UV light, making them suitable for outdoor or UV-exposed applications.
Therefore, Delrin is more suitable for sliding parts such as gears and bearings, while Nylon is more commonly used in scenarios requiring a certain level of toughness and impact resistance, such as ropes or gaskets.
Additionally, Delrin has higher rigidity, whereas Nylon offers greater flexibility and impact resistance, making each material suitable for different applications. For more information, please click to read “Delrin vs Nylon.”
Conclusion
Delrin, a versatile thermoplastic, excels in injection molding due to its superior mechanical properties, low friction, and high wear resistance, making it ideal for precision engineering components.
Its excellent dimensional stability and low moisture absorption ensure reliability across diverse environments, though it has limitations in high-temperature and chemical exposure.
Widely used in automotive, electronics, and consumer goods, Delrin is a top choice for durable parts.
Considering switching from metal to plastic components? Contact FOWMOULD! With 40 years of expertise, we offer cost-effective, customized Delrin injection molding solutions tailored to your needs.