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 Copolymer
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!
High Standards And Procurement From Reliable U.S. Manufacturers
Industrial Plastic Supply Inc. is ISO-9001:2015 certified. This benefits our customers since this certification communicates that we take quality and consistency seriously. We distinguish ourselves by providing Acetal Copolymer rods and sheets of exceptional quality over and over again so customers don’t have to wonder what they are getting when they do business with us.
American sourcing is another point of pride. In a time of global trade, a distributor may choose to do business with suppliers outside the U.S.. However, we believe that American quality and standards are top of the line. As such, our Acetal Copolymer is sourced from U.S. manufacturers. Our business partners – customers and vendors alike – can take pride knowing that their investments and dealings with Industrial Plastic Supply benefits U.S. customers, employees, and communities.
U.S. Sourcing Advantage
The benefit to customers in sourcing plastic from U.S. producers is more than patriotic or sentimental. Fact is, supply chains are more delicate than many of us imagine. Whether due to natural disasters, materials shortages, or politics, supply chains can fray and even snap. When that happens, price predictability and long-term supply/shipping agreements are thrown into disarray. Customers don’t want to hear excuses and “maybes” after they have signed contracts, paid money, and anticipate Acetal Copolymer products.
We pride ourselves on stocking and providing quality North American made Acetal Copolymer produced under the trade names: Tecaform® AH, Sustarin® C and ZL® 900. Each of these quality brand names are widely known for exceptional quality, consistency and durability.
Why Acetal Copolymer Is A Good Investment
Acetal Copolymer Performance Plastic
Acetal Copolymer is FDA compliant, opening up its use for food processing and packaging. The material is also stiff, resilient, and abrasion-resistant to a very high degree. Industrial Plastic Supply provides Acetal Copolymer materials in natural (white), black, and blue. Its stiffness and ability to hold shape under harsh conditions means that Acetal Copolymer sheets and rods can be shaped with standard cutting tools. This quality Copolymer Acetal material is FDA and NSF approved.
There are several special grades of Acetal that are formulated for tough food processing applications. Acetal Copolymer is available in a food grade blue for optical detection during food processing. This eliminates broken parts from getting into finished food products. There are also ultra detectable grades that are visual, x-ray and metal detectable for high end food processing applications. Contact us for more information on these special materials.
Automotive, Aerospace, and Medical Use
This plastic has exceptional ability to hold shape under stress, making it an excellent product in automotive and aerospace hardware. Gears, rollers, fuel lines, pumps and medical equipment all make use of Acetal Copolymer. However, care must be taken that the Acetal Copolymer is not exposed to temperatures above roughly 230 Fahrenheit (110 Celsius).
Safety Considerations
There are several factors to keep in mind when handling Acetal Copolymer:
Upon intense heating, Acetal Copolymer releases formaldehyde and carbon monoxide.
If machining or grinding, small Acetal Copolymer dust particles pose an inhalation and explosion hazard.
Prolonged exposure to UV light degrades Acetal Copolymer exposed surfaces and may change physical resilience.
Therefore, proper procedures must be taken when handling and machining this material. This is something Industrial Plastic Supply Inc. takes very seriously, not just for compliance reasons but also for the health and well being of our employees, customers, and ultimately the end-users.
Contact Industrial Plastic Supply for Acetal Copolymer
Industrial Plastic Supply Inc. is proud to be a distributor of Acetal Copolymer and other polymers. Contact us today for a quote and details about products, delivery, prices, and more. Call us @ 866-832-9315
Gehr Plastics Announces Huge 24″ Diameter Acetal Rod
Gehr Plastics is an industry leader in large high performance plastic materials. They announced at this years IAPD Conference in San Diego, the new production of 24″ diameter (600mm) Natural Copolymer Acetal Rod.
Being an industry leader is more than making the largest material, it is also about making the best quality material. Gehr Plastics is ISO 9001 and ISO 14001 approved and certified, guaranteeing a consistently high quality product. The product line that Gehr Plastics produces is also quite large. The materials include: ABS, Acetal (POM-C and POM-H), HDPE, Kynar, Noryl, Nylon, PEEK, PEI, Polypropylene, Polysulfone, PPO, PVC (Type 1, Type 2 and CPVC), PVDF and Ultem materials. All of these materials are available in a wide range of sizes, and yes, some of the largest.
Gehr Plastics Long History
Gehr Plastics has been leading the industry in innovation since 1932, and is now in the third generation of family owned and operation. From the wide range of materials to the extremes in size range, this is cutting edge performance from a family run company. They also released a web-app for picking plastic materials, Gehr Plastic Selection Tool, and it is also available for mobile devices. This comparison tool compares not only plastics, but metals as well, for a great look at the best physical properties for an application.
While quality and size are keystones to excellence, Gehr Plastics is also interested in materials that the rest of the industry has not
Large Cast Nylon Type 6 Rod
considered. Over the last several years, Gehr has produced some PLA materials (made from plants) and even a Clear Nylon Rod for higher temperature sight-glass applications. These are just a few of the cutting edge areas that Gehr Plastics is leading in this industry.
Industrial Plastics is Master Distributor
Gehr Plastics materials are sold through a tight network of Master Distributors throughout the United States. Industrial Plastic Supply, Inc. of Anaheim, CA is proud to be one of the top selected suppliers of these innovative materials. Contact us for any of these high quality and wide size range materials, call us @ 866-832-9315 or send us a note here.
Delrin® Homopolymer Acetal compared with Acetal Copolymer
Many of our clients assume that Delrin® rod and Acetal rod are the same thing. This is not true.
Yes, all Dupont Delrin® rod is Homopolymer Acetal rod, but not all Acetal rod is Delrin® rod.
Delrin® is the trade name for Homopolymer Acetal made by Dupont. Dupont™ Delrin ® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.
This is the most recognized of all trade names for Acetal materials, but not the only available Acetal material. The Copolymer Acetal resin is produced by a wide variety of large plastic manufacturers, BASF is probably one of the largest and most well known. Some main resin names are: BASF Ultraform® H4320, Kepital® F10-02, Hostaform® M25 and many others.
While Delrin® Homopolymer Acetal is a wonderful material, in a larger cross sections Homopolymer can exhibit center line porosity, or ‘soft centers’. This can sometimes be seen with the naked eye, and is a darker white in a normally milky white natural colored material. This center line porosity can cause problems in some applications. This porosity can cause leakage of fluid if under pressure, or soft center’s of homopolymer rod and sheet.
This should not stop you from considering Delrin® Homopolymer Acetal though. Many other properties of the homopolymer resins are superior to the copolymer resins. These properties are:
General Property
ASTM Test
Typical Value Unfilled Homo-Polymer
Typical Value Unfilled Co-Polymer
Specific Gravity
D792
1.42
1.40
Tensile Strength Yield
D638
9,600 – 11,000
9,000 – 10,200
Tensile Modulus
D638
450,000
400,000
Izod Impact – Notched
D256
1.2
1.0
Hardness – Rockwell
D785
M94
M90
Deflection Temp @ 264psi
D648
257
220
Deflection Temp @ 66 psi
D648
347
335
Water Absorption @ 24 hrs
%
0.24
0.25
Co. Thermal Expansion
D696
6.83X10-5
5.4X10-5
Some key properties for homopolymer acetal are: higher tensile strength, increased Izod impact, higher deflection temperatures and it is slightly harder. The co-efficient of thermal expansion is a bit higher, and needs to be considered when designing a new part. Extruded Delrin® brand homopolymer resin material also comes in several resin variations, including: Delrin® 150 and Delrin® 507, contact us for details. Dupont™ Delrin® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.
Many of our clients prefer the homopolymer rod and sheet for small machined parts. This is due to the increase in a few key properties, and of course brand recognition. Some of our major brand names for quality Copolymer Acetal (POM-C) sheet and Rod include: Tecaform AH®, Sustarin C®, ZL 900® and Pomalux®.
Both resins meet the standard ASTM-D-6778, and the cancelled specs, L-P-395 and ASTM-D-4181. Contact us for certification and specifications you may require.
The Acetal family of plastic resins are excellent for wear resistance, great mechanical strength, and superior machining properties. It is available in a huge range of sizes and shapes. Click here for more details on Acetal – Homopolymer Acetal Rod, and sometimes referred to as plastic dowel. We also have the capacity to supply colored Acetal Copolymer or Delrin® Homopolymer Acetal rod; click here from more details on the colored Acetal material.
Similar materials to Acetal Copolymer – Homopolymer Acetal are Nylon Rod, PET Rod and Noryl® Rod. Most materials are available as round rod, square rod, bar, strip, sheet and plate.
Please contact us for more details on these and other plastic materials. For a comparison chart of plastic materials click here: Plastic Materials Selection Guide
**Note: Delrin® is a registered Trademark of Dupont
Acetal Copolymer and ABS (Acrylonitrile-Butadiene-Stryene) have some similar properties but are really very different materials. They similarities are: high impact strength, ease of machining with standard cutting tools and good mechanical properties. They are also both FDA compliant and are both good substitutes for brass. They also have great water absorption resistance and good electrical properties. Both materials are good for some of the same applications but certainly not all. Listed below are some of the major differences.
ABS Sheet and Rod Information
ABS comes as Natural (straw) and Black color in Plate, Slab, Sheets and Rods, and thin sheet (.040″ – .250″) it is available as White or Black with a textured surface one side. It can be cut from 48″ X 96″ sheets into strip, panels or pieces.
ABS is formable. ABS is a great thermo-formable material while Acetal is not. Acetal is used more for machined parts such as gears and screws. ABS is great for molding and shaping parts from vacuum to heat forming. Excellent for model building and prototype projects.
ABS is easily bondable (similar to PVC). ABS can be bonded or welded to itself. Because Acetal is self lubricating, it is not possible for anything to stick to it unless etching is done – therefor it is not bondable.
ABS is a great material for painting and silk screening. While Acetal can not be painted or silk screened unless it has undergone Corona Treating (a flame surface treatment), but if treated will nice paint or screened surface.
ABS has better chemical resistance than Acetals. Both are attacked by acids like sulfuric, but ABS has a wider range of resistance to chemicals like aqueous acids, alkaline and alcohol. Acetal will degrade when exposed to such chemicals as chlorine and alkaline.
Specialty grades of ABS are available, including: Glass Filled, Static Dissipating, and Fire Retardant Grades (like Royalite – R59)
ABS Typical Properties Table
General Property
ASTM Test
Value
Specific Gravity
D7921
1.08 – 1.25
Tensile Strength
Yield D638
4,100
Izod Impact – Notched
D256
7.7
Hardness – Rockwell
D785
R105
Deflection Temp @ 264psi
D648
177
Co. Thermal Expansion
D696
5.3X10-54.6 -5.5X10-5
Acetal Copolymer and Homopolymer Sheet and Rod Information
ABS Resin Structure
Acetal is the better machining plastic, considered the best machining plastic material. Because of its durability and wear resistance, Acetal is an excellent choice for producing a wide variety of parts that require high wear resistance over a wide period of time. When machining to tight and specific tolerances, Acetal is ideal.
Acetal has low co-efficient of friction. Due to its self lubricating properties, it is a great material for sliding and wear applications. This material provides years of maintenance free bushings and bearings.
Acetal sheet is produced from .062″ – over 6″ thick and sheet sizes of up to 48″ X 120″ as standard. The standard color for Acetal and Delrin is Natural (a deep milky white) and Black. Some colors are available as Medical Grade, and can be obtained in limited sizes. These sheet are available cut to: slabs, blocks, plates, slabs and blocks.
Acetal (Polyoxymethylene) can be both a homopolymer and a copolymer. The homopolymer acetal has a repeating chain of one atom while the Acetal copolymer has two atoms forming a repeating chain. Dupont™ Delrin® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.
Acetal – Delrin Properties Table
General Property
ASTM Test
Typical Value Unfilled Homo-Polymer
Typical Value Unfilled Co-Polymer
Specific Gravity
D792
1.42
1.40
Tensile Strength Yield
D638
9,600 – 11,000
9,000 – 10,200
Tensile Modulus
D638
450,000
400,000
Izod Impact – Notched
D256
1.2
1.0
Hardness – Rockwell
D785
M94
M90
Deflection Temp @ 264psi
D648
257
220
Deflection Temp @ 66 psi
D648
347
335
Water Absorption @ 24 hrs
%
0.24
0.25
Co. Thermal Expansion
D696
6.83X10-5
5.4X10-5
ABS and Acetal – Similar, but very different materials
Both of these materials possess excellent qualities and have a wide range of different uses. Acetal is great for machining, while ABS is great for forming and bonding. They both can be used for machined parts and are great choices for food contact and electrical applications. These two materials are both strong and durable plastics, but one might be better than the other for a specific job. When picking the right plastic, it is important to compare plastics and their specific properties to make sure the material won’t fail and that your job will be successful.
Contact us for additional information, call us at 866-832-9315 or contact us here. Consider Industrial Plastic Supply for all your plastic needs, we want to be your go-to plastic supplier.
**Note: Delrin® is a registered Trademark of Dupont
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