Plastic is a widely used material due to its easy handling and recyclability. It may be engineered or found in natural form. However, engineered plastic comes in two main types: acetal and Delrin. Some people favor Delrin due to its advanced properties. Conversely, some consider acetal a reliable option. So, the difference in opinion among the masses raises debate on acetal vs Delrin.

 

Due to their similar origins, many people mix them and consider them equal. Right? But this is a misconception. Several differences set Delrin and acetal apart from each other. Knowing those contrasts is crucial before their final selection. Are you new to the concept of Delrin and acetal? This guide is a simple solution to your equation and confusion. So let’s get started!

 

Overview of Acetal

 

Acetal is a synthetic or simply an artificial thermoplastic. The scientific name of this plastic is polyoxyethylene (POM). But how is this plastic manufactured? Let me explain its production process in simple words. It is manufactured through polymerization of formaldehyde. Formaldehyde is a colorless gas.

 

Several formaldehyde monomers are bonded in the polymerization process to form a long chain. This long chain is called the polymer or acetal. Once the polymer is produced, it undergoes an injection molding process. Here, it is transformed into definite shapes and products. Through such a detailed process, acetal gets extra rigidity and strength. Let’s discuss the properties of acetal.

 

Properties of Acetal

 

  • Color and Appearance: As I mentioned above, formaldehyde is colorless. So, almost all grades of acetal are opaque or white. But you can customize it using different colors to improve aesthetics.
  • Mechanical Strength: Acetal has higher mechanical strength. It does not deform easily under high pressure. Moreover, the polymerization process makes acetal stronger. It can easily withstand heavy loads.
  • Low Friction and Wear Resistance: Acetal has a lower friction coefficient. It means that the acetal can easily slide or rotate against other surfaces. So, this property prevents it from unwanted wear and tear.
  • Dimensional Stability: Acetal maintains its dimensions in all environments. When heat is applied, it retains the original dimension during its manufacturing. So it does not shrink or expand in temperature fluctuation areas.
  • Surface Finish: Acetal naturally has a smooth surface, which helps maintain low friction. However, you can also apply other finishes to enhance its smoothness further. 

 

Types of Acetal 

 

Here is a brief introduction to three common types of acetal plastic. 

 

  • Homopolymer Acetal (POM-H): “Homo” means the same. As the name indicates, this acetal type has similar monomers. In simple words, it is manufactured using repeating units of only formaldehyde. Due to the same building blocks, homopolymer acetal has more even surfaces. Therefore, it is used in fuel components systems, gears, and handles.
  • Co-polymers Acetal (POM-C): “Co” means different. So, this type of acetal is made using different monomers along with formaldehyde. Mostly, manufacturers prefer ethylene oxide as an extra monomer. Ethylene oxide adds chemical resistance and flexibility more than homopolymer acetal. It is used in bushings, kitchen appliances, and electrical connectors.
  • Modified Acetal: As the name suggests, this type of acetal is modified in several ways. HOW? Several additives are added to enhance its properties. Those include glass fibers, UV stabilizers, and lubricants, which are the most commonly used additives. These additives give the acetal more strength, UV resistance, and reduced friction.  

 

Overview of Delrin

 

Delrin is a special type of engineered plastic first manufactured by an American company named DuPont. It also belongs to the polyoxyethylene family, but it is an advanced acetal form. But remember that all Delrin is acetal, but not all acetal is Delrin. The reason lies in their difference in the manufacturing process.

 

The manufacturing process of Delrin involves polymerization. However, polymerization in its manufacturing is anionic, which ensures high crystallinity. All the monomers in Delrin are entirely made of formaldehyde. There is no single different monomer. Therefore, it maintains a more uniform crystalline structure than acetal.

 

This uniform structure enhances all its properties. For example, it is more durable, strong, chemical-resistant, and impact-resistant. Due to its improved properties, Delrin stands out for different heavy-duty operations. It is used in the automotive, aerospace, and electronic industries. Let’s discuss the common properties of Delrin plastic. 

 

Properties of Delrin

 

  • Electrical Properties: Delrin is a poor conductor of electricity. The reason lies in its compact and uniform structure, which does not allow electricity to pass. In other words, Delrin is a good insulator. So, you can use it to protect electrical appliances.
  • Dimensional Stability: Due to uniformity in structure, Delrin is extraordinary in dimensional stability. During its manufacturing process, it absorbs moisture from its surroundings. So, it maintains its size and shape for a long time. Moreover, in temperature fluctuation, Delrin does not expand or contract.
  • Thermal Properties: Delrin has a higher melting point than other plastics. Thus, it does not quickly melt and can withstand heat without losing strength. Moreover, Delrin has a low coefficient of thermal expansion. Hence, it does not readily expand on cold winter days.
  • Mechanical Properties: Delrin has top-notch mechanical properties. For example, its tensile strength is more significant, so it does not break easily when pulled. Moreover, it has high rigidity and low friction.
  • Processing Properties: Delrin is straightforward to process. Though it is a rigid material, it offers easy machining. For example, Delrin can be processed using milling, drilling, turning, and cutting operations. Moreover, it is easy to inject into molds to create complex shapes. 

 

Grades of Delrin

 

Delrin comes in various grades to meet specific applications. Each grade possesses unique properties. Take a closer look at them!

 

  • Delrin 150: This grade of Delrin perfectly balances various properties. For example, it has high mechanical strength and rigidity. Moreover, it has low friction resistance to prevent wear and tear. Thus, Delrin 150 is mainly used for general purposes, such as gear and consumer products.
  • Delrin 511P: This grade is manufactured with enhanced mechanical properties. It possesses excellent tensile strength and resistance to routine stress. It is also known as a high-strength grade.
  • Delrin 500AF: It is a highly self-lubricant grade. During its manufacturing, Teflon fibers are added. These fibers provide extra lubrication and reduce friction. So, it is used in bearing, sliding components, and conveyor parts.
  • Delrin 570: Commonly known as glass-filled Delrin, it imposes high strength. It is manufactured using glass fibers. These fibers add stability and stiffness. Moreover, they are less prone to deformation under heavy loads.
  • Delrin 525GR: This grade is the combination of two grades. It contains glass fiber and self-lubricants. So, you can get stiffness and low friction at the same time. Moreover, thermal stability is more improved in this grade. 

 

What are the Differences Between Acetal and Delrin?

 

Delrin and acetal share the same family tree but are still very different. Let’s explore the main differences between Acetal and Delrin plastics. 

 

1- Composition

 

The main difference lies in the composition of both types of plastic. As I said above, both belong to the same origin, but their final composition varies in many ways. For example, acetal includes formaldehyde monomers with other types of monomers. In simple words, its composition involves co-polymers.

 

Different types of monomers are introduced to resist moisture absorption and heat. Conversely, Delrin is also a formaldehyde polymer but does not include other monomers. It is manufactured using the same and repeating unit of formaldehyde. Simply put, it involves homogenous compositions. So, Delrin is more prone to moisture absorption. 

 

2- Durability and Strength

 

Due to different compositions, acetal and Delrin offer differences in durability and strength. If we debate over acetal, it involves co-polymers. So it is more resistant to heat and moisture. However, the mechanical strength of acetal is slightly compromised due to the mixed composition. It is less rigid and less stiff than Delrin. Still, it is more resistant to cracking and wrapping.

 

Conversely, Delrin has uniformity in its structure. It is made with the same repeating units, so this plastic’s strength and durability are highly improved. For example, Delrin can withstand heavy mechanical loads. Moreover, the tensile strength is also significant. So it does not easily break under stress. Such higher strength increases its durability and lasts for a long time. 

 

3- Tensile Strength

 

Tensile strength refers to withstand pulling force. In easy words, tensile strength is the ability of any material to withstand high stress without deforming. So, both acetal and Delrin behave differently in terms of tensile strength. For example, acetal can withstand a pulling force of 8,000–9,500 psi. This has a significant tensile strength compared to other plastics.

 

However, it is not recommended for heavy-duty stress environments. Conversely, Delrin maintains uniformity in its structure. So, Delrin’s tensile strength is about 10,000–12,000 psi, which is more significant than acetal’s. It can withstand high pulling forces without deforming or losing its structural integrity. 

 

Quick Highlight: Delrin maintains its tensile strength only in dry places. When you use it in a moist environment, it absorbs the moisture and loses its tensile strength. Although acetal has low tensile strength, it maintains this strength even in humidity. 

 

4- Chemical Resistance

 

The chemical resistance of a material indicates its ability to withstand chemical exposure. Both types of plastic offer excellent chemical resistance compared to other plastics. However, a slight difference arises due to their composition. When discussing acetal, it can withstand organic solvents such as alcohols and hydrocarbons.

 

Moreover, it also shows resistance to acids and bases, even in moisture. But when acetal is exposed to strong oxidizing agents, it starts deteriorating. On the reverse side, Delrin plastic shows superior resistance to all types of chemicals. In dry conditions, it can also withstand strong oxidizing agents. However, in a wet environment, it shows structural degradation. 

 

5- Temperature Tolerance 

 

Temperature tolerance is another factor that differentiates acetal and Delrin. For example, acetal shows resistance up to Around 90°C (194°F) in high temperatures. Above this temperature, it starts melting and loses its structural reliability. Moreover, in low temperatures, it can withstand -40°C or -40°F. Acetal shows shrinkage above this temperature.

 

On the other hand, Delrin is a clear winner in temperature tolerance. Its maximum heat resistance is up to 120°C (248°F) temperature. In contrast, it does not shrink in low temperatures below -40°C. This high tolerance is due to its dimensional stability. So, you can use Delrin in applications that require high-temperature tolerance. 

 

6- Porosity

 

Porosity is the presence of tiny holes in a material’s surface. These holes can affect its strength and dimensional stability. Acetal has zero porosity, which means its surface has no small holes. The reason lies in its manufacturing process. Added processes such as finishing make its structure more uniform by eliminating holes.

 

Therefore, due to its low porosity, acetal’s moisture absorption capacity is very low. Conversely, Delrin also contains low porosity but is higher than acetal. This means small holes can change Delsin’s dimensional stability in moisture. Therefore, with its high strength and durability, it is best used for dry applications.  

 

7- Applications

 

Due to variations in the composition, the usability of acetal and Delrin varies for different purposes. The typical applications of acetal include:

 

  • Acetal is used to produce fitting valves due to its lack of moisture absorption.
  • Use in engine compartments due to resistance to fuel and oil.
  • It is used in consumer goods such as toothbrush handles due to its lightweight nature.
  • Acetal is used in medical devices such as drug delivery systems and laboratory equipment.

 

However, Delrin is more versatile regarding properties such as rigidity and strength. So, its applications are typical where precision is a significant concern.

 

  • Aerospace industries use Drilin to make door latches and aircraft interiors.
  • It is used in high-precision components such as gears, cams, and levers.
  • You can find Delrin in ski bindings and fishing reel parts to provide high strength.
  • Delrin is an FDA-approved material. So, most industries use it in food-processing equipment. 

 

8- Cost and Affordability 

 

Cost is another distinguishing factor between Delrin and acetal. Acetal involves a simple production process with two or more types of polymers. Using co-polymers eliminates the demand for purity, reducing added treatment costs. Moreover, it is produced worldwide, which creates competitive pricing. So, overall, acetal is low-cost and more affordable.

 

On the other hand, Delrin is an exclusive product of DuPont, so the brand’s name enhances its prices. Moreover, Delrin’s production process is slightly complex. It involves all homopolymers, which demand purity and uniformity. Lastly, improved properties such as strength, durability, and precision make Delrin expensive. 

 

Choosing the Right Material

 

Choosing between Delrin and acetal is a critical decision. However, it is crucial to select the right material to prevent unwanted outcomes. Let’s explore when to choose Delrin and when to choose acetal.

 

  • The first step is understanding the requirements of your project. Understand the environmental condition in which you want to use Delrin or acetal.
  • For a moist environment, acetal is a reliable option. The reason lies in its zero porosity. However, you should go for Delrin for dry conditions and more strength.
  • If your project demands customization, Delrin is the best suited for you. As you know, it comes in various grades. All those grades offer unique charactertics. On the flip side, for simple projects, you should prefer acetal.
  • Lastly, keep your budget in mind. If you have a tight budget and your project is not concerned with higher mechanical strength, acetal is your go-to option. However, if you are concerned with strength and reliability, you should go for Delrin. Although it demands higher prices, it offers long-term cost-effectiveness with its durability.

 

Conclusion 

 

Delrin and acetal are two different types of engineered plastic. Although they belong to the same family, they vary in many aspects. In this article, I have explored the main differences between Delrin and acetal. For example, Delrin stands out in strength and durability than acetal.

 

Moreover, Delrin’s temperature resistance is also higher than that of acetal. However, due to its low porosity, acetal wins in moisture absorption. It can withstand chemical exposure in wet places. So, each type offers unique properties. Choosing the right option depends on your budget and project requirements. 

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