Differences Between Acetal Vs Delrin

Introducing Acetal

Acetal polymer, often known as POM, is a plastic that uses several monomers in its CH2O repeating units. Acetal, also known as polyformaldehyde or polymethylene glycol, acts like metals and has several other names. As a result, it can be used as a substitute for metals in plastic machining and other industrial applications.

Acetal’s Characteristics

The following characteristics are typical of acetal plastics, whether they are copolymer or homopolymer.

• Easily recyclable due to its melting point range of 1620°C to 1750°C
• High electrical impedance
• Slow absorption of water
• Low friction coefficient
• Superior toughness and stiffness

Acetal Varieties

Copolymer acetal (POM-C) and homopolymer acetal (POM-H) are two forms of acetal, each having its own set of characteristics.

POM copolymers, on the other hand, have varied monomeric units inside their CH2O repeating units. They are crucial in injection molding and plastic extrusion because of their high dimensional stability, chemical and abrasion resistance. They come in a wide range of colors, from black and blue to red and green and even brown. Celcon®, Duracon®, Hostaform®, Tepcon®, and Ultraform® are all brand names for the same product.

Below, we’ll go into detail about acetal homopolymer, also known as Delrin®, a major brand name, and how it doesn’t change the repeating CH2O units. Homopolymer and copolymer acetals include Acetron®, Kepital® POM, Sustarin® C, Tecaform®, and TenacTM-C, among others.

Intro to Delrin

DuPont markets their acetal homopolymer under the brand name Delrin plastic. It is composed of CH2O units that can be extended or shortened to produce various forms. Putting aside its other qualities, its fast flow rates and high tensile strength make it a common material for plastic machining and injection molding, respectively.

Delrin characteristics

Delrin’s superior mechanical qualities set it apart from acetal copolymer. It’s missing a couple other things as well, though. Read on to learn about Delrin’s characteristics.

• Central or longitudinal areas of low density porosity
• Tolerant of Chemicals
• High flexural modulus and excellent rigidity at both room and increased temperatures.
• Superior strength under stress
• Low-friction, hard material.
• Superb resilience to creeping
• Strong current
• Recyclable
• Exceptional electrical resistance

Delrin Qualities

Delrin comes in a wide variety of grades because of its malleability and the fact that it retains its homopolymer structure when modified. There are different uses and characteristics for each grade. The following are some typical grades that may be applicable to your work.

• Delrin 150 has superior mechanical qualities than those of any other acetal. It is extremely strong and rigid, and it doesn’t distort even when heated to extremes. In addition to being durable, its high lubricity makes it resistant to wear and tear.
• Durable, wear-resistant, and naturally lubricous, Delrin AF 100 (13% PTFE Filled) is an excellent choice for a wide variety of applications. When PTFE (polytetrafluoroethylene) is incorporated into a material, it gains strength and durability.
• Delrin (with 30% glass fill): This grade of Delrin is ideal for producing objects that will be under persistent stress, as it has uneven impact resistance.
• Delrin AF DE588 has enhanced rigidity, strength, and longevity because to the inclusion of 20% PTFE fibers. Submarine components can be made from this crucial Navy material.
• All Delrin grades are exceptionally easy to machine, making them ideal for use in a wide variety of applications. The qualities of the material offer it an alternative to traditional machining materials for use in fast prototyping. The similarity between Delrin and nylon, for instance, is demonstrable. 

Are Delrin and Acetal the Same Thing?

Delrin is not the same as acetal. Acetal belongs to the family of semi-crystalline polymers known as polyoxymethylene (POM). Delrin is the brand name for an acetal homopolymer in which the CH2O units repeat endlessly. Clearly, the acetal plastic vs. Delrin comparison is flawed; instead, the acetal copolymer vs. Delrin comparison is more appropriate. POM with a substituted monomeric unit, such as acetal, is a copolymer that also contains CH2O units.

They share a common ancestor but have very dissimilar estates. The tensile strength of Delrin, for instance, is greater than that of acetal. Because of its reduced thickness, it is the superior choice for building miniature, paper-thin representations of actual structures.

What Sets Acetal Copolymer Apart from Delrin?

Delrin is related to other acetal copolymers. This accounts for their individuality despite its varied merits and uses. Differences between the two types of material are outlined below.

Put together

Since Delrin’s repeating units have end caps, it is classified as a homopolymer. Acetal copolymer, on the other hand, incorporates new monomers at random locations along the chain every 70-100 units.

Therefore, the crystalline structure of both materials is affected by the molecular variations. In this case, the orderly slacking of the polymer gives Delrin its massive crystalline structure, while the copolymer destroys this organization.

Degree of Difficulty

Delrin and acetal have similar levels of hardness, hence the differentiation between them is subtle. And yet, it’s significant. The hardness scale runs from 86 on Delrin to 85 on POM copolymers. Because of this, Delrin will be less likely to wear out or crack when subjected to force. The coefficient of friction will be reduced as well. This means it can readily glide across components.

Chemical Imperviousness

When compared to Delrin, acetal copolymers have greater resistance to high temperatures and caustic solutions with a higher pH value. Therefore, they are superior for use in producing components subjected to these circumstances. Delrin, on the other hand, is immune to the effects of chemicals and can’t be eaten by fungi, insects, or any other living thing.

Acceptable Temperature Range

Delrin may be used in temperatures between -40 degrees Celsius and 120 degrees Celsius, making it a more flexible material than acetal. It retains its toughness even in subzero conditions and is unbreakable under impact. But even at its hottest, it can hold up to 1750 degrees Celsius.

The temperature range at which copolymers can function is up to 100 C. However, they can function at temperatures of up to 1400C for a limited time.

Neither one can withstand temperatures so high.

Combined Flexural and Tensile Yield Strength  

When deciding between acetal and Delrin, flexural yield and tensile strength are also crucial factors to consider. The yield strength of acetal is 9,500 psi, while that of delrin is 11,000 psi. And while acetal has a tensile strength of only 12,000, Delrin’s is 13,000. This demonstrates that both materials may be used to make accurate structural models. Delrin, on the other hand, has a higher strength-to-weight ratio, making it better suited for structural components.

The Concept of Porosity

Delrin can hold tiny bubbles or spaces thanks to its porous or lower-density core. As a result, air and water can easily penetrate the surface. The pores of copolymers are closed. Therefore, they are better suited to creating components for areas where porosity is frowned upon, such as the food and medical industries.

Method of Use

Both are useful in a wide variety of mechanical and industrial contexts. However, there is a catch to these properties. Delrin is more suited for components that require a tough POM material, while acetal is better suited for those that require a POM material with good chemical resistance.

Both plastic and metal can be molded and machined, as well as 3D printed, to create a wide variety of components used in fields as varied as transportation, building, consumer products, electricity, food processing, and packaging.

POM materials are inexpensive, with the going rate for typical copolymers being between $1,500 and $2,500 per ton. Delrin, on the other hand, is more expensive than the others because of its name recognition and superior mechanical qualities.

When to Choose Acetal and When to Choose Delrin

You should be able to make an educated prediction about when to use each material based on their individual characteristics. When to use each resource is discussed below. using quick prototypes.

Burdensome Weights

Strong tensile and yield strengths are shared by both materials. However, due of its greater tensile and yield strength, Delrin is the superior choice for producing components that apply constant heavy load over extended periods of time. Delrin grade should be used when the component is going to be subjected to repeated impact.

Wear and Tear

The frictional resistance of delrin is much smaller. Therefore, it’s the best material to use when creating components that will rub or slide against another metal or plastic. No additional oil or grease is required for use.

Lightweight and Dimensionally Stable

Acetal copolymers are a lightweight option that maintains its shape. A massive crystalline structure is disrupted when the plastic material does not adhere to the ordered pattern of the polymer, reducing the dimensional stability.

Chemical Imperviousness 

When comparing acetal to Delrin, this is a significant difference. Acetal can be used since it is resistant to both basic and acidic conditions. Industrial solvents, lubricants, and agricultural chemicals will have no effect on the component because to its great chemical resistance.

Fire Danger and Temperature

Both forms of plastic should be avoided when creating components that will be subjected to sustained heat of more than 90 degrees Celsius. Don’t soak in water that’s too hot (above 60 degrees Celsius) for too long. In addition, both are extremely combustible and cannot be used in any circumstance that necessitates a flammability grade of HB or higher.