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Acetal Copolymer vs Delrin® Homopolymer Properties

Acetal Copolymer vs Delrin® Homopolymer Properties

Comparing Acetal Copolymer to Dupont Delrin

Comparing Acetal Copolymer to Dupont Delrin

Acetal Copolymer vs Dupont Delrin® Homopolymer: Properties and Benefits of Each

Industrial Plastic Supply, Inc. has been supplying a vast inventory of plastics to a wide customer base since 1975. Today, we put the spotlight on two products that are incredibly similar, but have key differences that result in each performing optimally in certain applications: the Acetal Copolymer and the Delrin® Homopolymer

Both of these acetal materials are incredibly similar, with similar beneficial properties. They are both compliant with FDA, ITAR, and RoHS standards. Both are very stiff plastics with excellent dimensional stability in average environments. They are self-lubricating, easy to cut with standard tools, and abrasion and wear resistant. The major differences between them however are a result of their differing structures.

What Is Polyoxymethylene

Polyoxymethylene (also known as POM for short) is an important and commonly used engineering plastic material. There are two distinct types of POM; the first is Homopolymer Acetal and is commonly called Dupont Delrin®. The other is Copolymer Acetal and is referred to by the trade names Celcon®, Sustarin® C, Tecaform®, Ultraform®, Kepital® and many others. Both versions of POM are very popular thermoplastic materials. They both are commonly used for parts that need to be stiff, dimensionally stable and have low surface friction. 

Delrin® Homopolymer

The homopolymer possesses much more regularity in its structure, with a repeated, crystalline pattern throughout the plastic. As a result of its strong, crystalline makeup, the Delrin® Homopolymer has superior physical properties, such as better fatigue and creep resistance, and bearing properties. Also, it has better short-term heat resistance compared to the acetal copolymer, with a much higher melting point.

However, this homopolymer does experience minor and inherent center-line porosity. This is basically a band area of tiny porous holes along the center of a rod or sheet. Depending on the severity of the porosity, these holes could weaken a finished part or cause other problems with its performance. 

Acetal CopolymerDupont Delrin compared to Copolymer Acetal

We’ve found that our customers tend to gravitate towards the acetal copolymer when they require a wider processing window, lower costs, and better long-term resistance to heat and alkaline environments. The acetal copolymer is not as crystalline in its structure, which causes it to not only have a generally lower melting point, but when incorporated with other materials, also increases the tolerance for high melting temperatures. 

The less crystalline structure of the copolymer means that this plastic isn’t quite as strong. However, its mixed molecular structure has several benefits. The acetal copolymer has improved resistance to oxidation, improved chemical resistance, and much better long-term resistance to heat. That difference in chemical resistance is much more pronounced with exposure to hot water, especially chlorinated water. The acetal copolymer survives much longer than the homopolymer in these conditions.

Final Thoughts

Both the Acetal Copolymer and the Delrin® Homopolymer have their benefits. Depending on your application and requirements, you can choose the best acetal based plastic for your needs. In need of a supplier of plastics and plastic materials? Check out the rest of Industrial Plastic Supply today!

Acetal Copolymer

Acetal Copolymer

Acetal Copolymer and Dupont Delrin Rod Tecaform AH, Sustarin C and ZL-900

Acetal Materials

Acetal Copolymer / Dupont Delrin® 150SA Homopolymer


Which Acetal material should you use? (POM)

  • Both Acetal Copolymer and Delrin® 150SA Homopolymer are FDA Compliant
  • Both are very stiff and have excellent dimensional stability
  • Are Self Lubricating, Abrasion Resistance, and Excellent Wear properties
  • Available in Natural, Black and Blue. Custom colors also available.
  • Cuts extremely well with standard cutting tools
  • Delrin® AF (PTFE Filled), Glass Filled, and Specialty Grades Available
  • Delrin® 150SA Homopolymer have similar properties and frequently replace: Noryl®Nylon®, and PET or PBT materials
  • Acetal and Delrin® are High Tech Performance Plastics

Some reasons to choose Homopolymer vs. Copolymer

Both Acetal (POM) grades have very similar properties. Our clients seem to prefer the Dupont brand name Homopolymer materials because of the superior physical properties. The issues that lead clients to the Copolymer is a slightly lower cost, and the minor inherent center-line porosity in the Delrin® 150SA Homopolymer grade.

Dupont™ Delrin ® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.

The Delrin® 150SA is a brand name of Dupont, and it is often referred to as POM-H or Acetal Homopolymer. Common brand or trade names for extruded Acetal sheet and rod materials include: Tecaform® AH, SUSTARIN® C, ZL® 900-C, Pomalux®, Unital®, Mechatec Acetal®, Acetron® and many more. This excellent mechanical plastic material is also referred to as: Acetal Copolymer rod, Copolymer Acetal rod, Copolymer Plastic Rod, Acetal Copolymer vs Acetal Homopolymer, Homopolymer Acetal rod, Acetal Homopolymer rod, and many others.

Specializing in Wholesale Acetal and Delrin Engineering Plastics, Mechanical Plastics and High Performance Plastics

**Note:  Delrin® is a registered Trademark of Dupont

**See also: Alignable Acetal – Delrin Page

 

10-inch-Black-Acetal-Rod

Why you should use Acetal/ Delrin®

  • Both the Dupont Delrin® and Acetal Copolymer are FDA Compliant
  • They are very stiff and have excellent dimensional stability
  • Are self-lubricating, abrasion-resistant, and have excellent wear properties
  • Cuts extremely well with standard cutting tools
  • Delrin® AF (PTFE Filled), Glass Filled and Specialty Grades Available
  • Delrin® Rod and Plate have similar properties and frequently replace: Noryl®Nylon and PET materials

Some reasons to choose Homopolymer vs. Copolymer

Both POM grades have very similar properties. Our clients seem to prefer the Acetal over the Homopolymer materials due to the inherent center-line porosity in the Delrin® Homo-polymer version. This means, that along the center of a rod, or the middle of a sheet, there is a band of area with tiny porous holes. This can weaken or cause problems with a finished part, and in extreme cases, you may see blow by or leakage at this center line. While Delrin® is a brand name, it is a POM Homo-polymer.

The most requested and popular item we supply is the Acetal; the POM Copolymer resin made by one of the other big resin manufacturers – like BASF or Celanese/Tacona.

Both Delrin and Acetal are ITAR compliant, and Delrin and Acetal are RoHS compliant.

The most requested and popular item we supply is the Acetal; the POM Co-polymer resin made by one of the other big resin manufacturers – like BASF or Celanese/Tacona.

Both of these premium performance plastic resins are readily available. If you would prefer the Delrin® brand Sheet or Rod, drop us a line, send us an email – we will be happy to ship the requested material for you. We don’t make judgments on the suitability of material for your application, we just supply what you, our clients ask for. Please, just let us know ahead of time if you have a preference. There are a few other names we hear when people are looking for Delrin®, like Delron, Delran, Delrun, Delren, and many more. Just let us know, and we will be happy to supply a high quality Delrin® brand or Copolymer Acetal product.

Want more information on the differences?  Acetal Compared With Delrin®  and Use The Best Wholesale Acetal Rod and Delrin® Rod Supplier. Natural Acetal Copolymer Rod Now Available up to 24″ in Diameter

Still not sure Delrin® or Acetal is the proper material for your application, consult our free Plastic Materials Selection Guide.

Industrial Plastic Supply proudly stocks Acetal and Dupont Delrin 150SA from these premium manufacturers:

Ensinger® Plastics for Dupont Delrin 150SA and Tecaform AH Copolymer Acetal

Rochling® Plastics for Dupont Delrin 150SA and Sustarin C Copolymer Acetal

Z/L Plastics® for Dupont Delrin 150SA and ZL® 900 series Copolymer Acetal

And many more ‘American Made’ quality plastic manufacturers.

Both Delrin and Acetal are ITAR compliant, and Delrin and Acetal are RoHS compliant.

Acetal materials are excellent machining materials – a favorite of machinists. Works like a soft brass, and has exceptional dimensional stability. It comes as a stress relieved material, however if you plan to do extensive machining, you may need to stress relieve the parts prior to final pass. Rods are machined well in lathe and mill, sheets are machined or cut in most common machine tools.

  • Excellent Machining
  • Low co-efficient of Friction
  • Very low moisture resistance

The work horse of the mechanical plastics family, it is one of the most popular grades of material we supply. Other brand or trade names: Pomalux®, Acetron®, Ensital®, Unital®, Tecaform®, Ultraform®, Celcon®, BASF®, Hostaform®, Ticona®, and Dupont Delrin®. Occasionally we are asked for the difference between Acetal and HDPE – here is an explanationApplications – Frequently used in:

  • Wear and Slide machined parts from Rod and Plate
  • FDA, NSF, 3-A, and USDA Compliant Machined Parts
  • Easily machined parts for water / moisture environments
  • Critical tolerance and dimensionally stable parts
  • 185 degrees F Continuous Temperature Environments
  • Rod and Rods, Sheet and Sheets for numerous applications

Acetal Sheet and Rod Specifications:

In stock we normally carry one of these resins: BASF Ultraform® H4320, Kepital® F10-02, or Hostaform® M25. Current Certifications and Specifications used for Acetal – Delrin®: FDA, USDA, NSF, ASTM D6778 Superseded or out dated Specifications for Acetal – Delrin®: L-P-392, ASTM D4181

Materials Available As

Delrin® Sheet – Delrin®Plate or Acetal Sheet – Acetal Plate: .062″ – 6.0″ up to 48″ X 120″ in Natural (White) and Black.

Acetal sheet and Acetal Plate thickness normally in stock: .125″, .187″, .250″, .312″, .375″, .500″, .625″, .750″, .875″, 1.0″, 1.250″, 1.500″, 1.750″, 2.0″, 2.250″, 2.500″, 2.750″, 3.0″, 3.250″, 3.50″, 3.750″, 4.0″, 4.50″, 5.0″ and larger

Delrin® AF Sheet and Plate: .062″ – 3.0″ thick in 24″ X 48″, brown in color

Delrin® AF Rod: .250″ – 10″ diameter rod in up to 120″ lengths, brown in color

Film: .005″ – .062″ up to 24″ wide in Natural (White) and Black (minimums may apply)

Acetal Rod and Rods: .125″ – 10″ diameter in Natural (White) and Black up to 120″ lengths For Colored Acetal – Delrin Rod® Read Here.

Acetal Rod diameters normally in stock: .125″, .187″, .250″, .312″, .375″, .437″, .500″, .562″, .625″, .750″, .875″, 1.0″, 1.125″, 1.250″, 1.375″, 1.500″, 1.625″, 1.750″, 2.0″, 2.250″, 2.500″, 2.750″, 3.0″, 3.250″, 3.50″, 3.750″, 4.0″, 4.50″, 5.0″ and many more – up to 20.0″ diameter rod is available!

Special Formulations: Conductive, Static Dissipative, PTFE-TFE Filled, Glass Reinforced, Custom Sizes, Formulations, or Colors Occasionally we are asked for the difference between Acetal and HDPE – here is an explanation.

Typical Resin Properties:

General PropertyASTM TestTypical Value Unfilled Delrin® Homo-PolymerTypical Value Unfilled Co-PolymerTypical Value Delrin® AF
Specific GravityD7921.421.401.50
Tensile Strength YieldD6389,600 – 11,0009,000 – 10,2007,600
Tensile ModulusD638450,000400,000400,000
Izod Impact – NotchedD2561.21.00.9
Hardness – RockwellD785M94M90M89
Deflection Temp @ 264psiD648257220260
Deflection Temp @ 66 psiD648347335347
Water Absorption @ 24 hrs%0.240.250.20
Co. Thermal ExpansionD6966.83X10-55.4X10-55.0X10-5
Acetal Copolymer Sheet and Rod

Properties are for evaluation purposes only. This information is not to be construed as a warranty, guarantee or assurance that you may achieve the same results. Materials made from different resin types, manufacturing techniques and manufacturers will react differently. The information should be used to compare against other materials only, and each user should make his own tests to determine suitability. No warranty as to this materials suitability are either expressed nor implied.

Are HDPE sheet and Homopolymer Acetal Sheet The Same Materials?

Are HDPE sheet and Homopolymer Acetal Sheet The Same Materials?

Is HDPE Sheet and Acetal Homopolymer Sheet the same?

Here is another popular question asked by our clients. Is HDPE the same as Acetal Copolymer  / Delrin Acetal Homopolymer?
No, they are two totally different materials. Although the natural color of both is a milky white to opaque white, and they do look a bit similar, they are not. (HDPE is milky white to almost translucent depending on thickness, and the Acetal materials are a more opaque white to slightly milky – once again depending on thickness . See picture below of .500″ thick samples of HDPE and Acetal sheets)HDPE compared to Delrin Acetal Homopolymer sheet

HDPE and Acetal – Some Differences

The HDPE sheet and rod is a softer material, and is commonly known for its FDA certification and used in numerous food applications, such as: one gallon milk jugs, cutting boards, colored water glasses/cups, and many, many more. While it can be machined, because it is a bit softer and lighter, the tolerances it can be machined to are not very tight. It is not bondable, so it makes a great non-stick surface for sticky foods and adhesives.


The Acetal Copolymer and the premium Delrin® Acetal Homopolymer also have FDA certification, and are used heavily in the food processing industry. This material is a more mechanical material and is used in bearing and wear applications, cams, feeder screws, etc. This material is can be machined to tight tolerances, and will wear for long periods without lubrication. Due to its exceptional wear properties, it is not bondable, thus requiring mechanical fastening or threads to assemble. It has a very low water absorption, and you will find it in your toilet tank as the white moving parts in the filler mechanism. It is an extremely popular material for machinists, as it works much like soft brass.


While HDPE Sheet and Acetal Sheet look similar, they perform quite a bit differently.

While both materials are FDA approved, are machinable and can be used to make rigid wear resistant parts, they are two different resins and have drastically different physical properties. Another major difference is in the weight of these items, HDPE sheet and rod material weighs about 35% less than the Acetal sheet and rod material. Please check the data sheets for more information to assist in proper material selection. Acetal Data Sheet and HDPE Sheet Data

Acetal is commonly known as: Delrin Homopolymer Acetal, Tecaform AH,Ensital, Unital, Pomalux, Ultraform and many more.

HDPE is also known as: Ultraethylux, Densetec, Polystone G, Fortiflex, Versadur, Hostalen, and many more.

Contact us for more details on the HDPE and Acetal families of plastic materials, e-mail us or call 866-832-9315
Topic: HDPE sheet and Delrin Sheet (Acetal Sheet)