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 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)
Which Plastic Sheet or Rod Material is right for me?
Mechanical Acetal Sheet
This not an easy question to answer. Several different factors come into play when choosing the right plastic for your application. Temperature, strength, exposure to the elements and even time spent at elevated temperatures are just a few factors to consider when choosing the right plastic for a particular project or job.
Picking the right plastic for your application is critical for its success and longevity and needed to insure that the material doesn’t fail in critical situations. From the onset it may take a bit of time to choose the right plastic material, but will ultimately pay off in the long run. Simply choosing the cheapest plastic sheet or rod may spell disaster for your project.
Many plastics are resistant to chemical attacks. Some plastics however are not. Two examples of plastic that have low resistance to chemicals are Acetal Copolymer and Nylon. Acetal and Nylon are both a great machining plastics with excellent wear resistance and impact strength. However, when exposed to chlorine or alkaline they tend to become brittle which can cause failure and if used in such instances as plumbing, can lead to major problems such as flooding. Nylon does have good resistance to many chemicals but will degrade when exposed to acids especially sulfuric. A plastic that would work better for applications involving the use of chlorine or acids is UHMW. UHMW has some of the same properties as Acetal such as wear resistance, ease of machining and are both self lubricating. UHMW often is an alternative for Acetal and Nylon, especially when it comes to chemical attacks.
Many plastic sheet and rod materials to choose from
Another plastic that can fail if used in the wrong application is Acrylic. Acrylic is a great plastic for displays and decorative purposes and is a natural replacement for window glass. However, it is brittle and has very low impact strength as opposed to Polycarbonate. Polycarbonate is a great plastic for impact strength, probably the best in the plastic family. It is 25 times stronger than
Massive Selection of Performance Plastic Rod
Acrylic and this makes it ideal for bullet resistant glass and riot shields, while Acrylic would be useless for those critical jobs. However, Acrylic has better U.V. resistance than Polycarbonate Plastic Sheet which makes it better for use outdoors over longer periods of time because it is invisible to sunlight. Another plastic that cannot handle U.V. rays is Polypropylene. Polypropylene unlike Acetal has excellent chemical and moisture resistance. However, unlike Acrylic, it becomes brittle in sunlight and starts to craze or crack when exposed over a period of time while Acrylic would last many years longer. Even though Polypropylene is a very rigid and stiff material, with good impact and crack resistance, if exposed to the elements for a period of time, it will not retain its properties and a chemical chain reaction will cause the material to eventually fail. Polypropylene is great at handling chemicals and food applications which neither Acrylic nor Polycarbonate Sheet are well suited because for this application, because they don’t have good chemical resistance and the standard grades are not approved for handling food.
These are just some examples of the differences between plastic resins and it is important to note that just because one plastic works for one application, it may not work for another. All factors must be considered and taken into account, maybe even some trial and error. This will insure that your project will go smoothly and will be able to last through many years of use, saving time, money and patience.
Contact us for more examples of materials and the differences between specific items. Also, we have a great tool to help you in choosing the proper plastic material for your application, check out our free Plastic Material Selector Guide. We would also welcome your email inquiries or call us at: 866-832-9315.
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
Can we get colored Acetal Copolymer – Delrin® Homopolymer Rod?
We get this question frequently.
The easy answer is yes, however, the most common available colors are Black and Natural (white in color). But to continue the thought, we have several manufacturers that run ‘Medical’ grades of Acetal Copolymer as well as Acetal Homopolymer (ie: Dupont Delrin® 150SA Homopolymer Acetal) in several colors. These materials are special run, but can frequently purchase by the standard length without a custom run. The biggest factor may be the price. The colored version of Acetal Copolymer – Delrin Homopolymer Acetal materials are dramatically more expensive.
Colored Acetal Copolymer – Dupont Delrin® Homopolymer 150SA Rod
While price is a factor, the benefits may out weigh the cost. Many of our clients use these colored rods to help differentiate their product from their competition. With colors that can come close to a logo color or match a machine, these advantages are clearly visible. Having a special color available to machine small to medium runs of your product can save you thousands over molding a new part for trials.
What colors can I get in Acetal Copolymer or Dupont Delrin® 150SA Homopolymer Acetal Rod?The range is a bit limited, but does include: brown, dark blue, dark green, gray, light blue, light green, red, rust and yellow (and of course Natural and Black). For details on the properties of these materials click here: Acetal Copolymer and Dupont Delrin® 150SA Homopolymer Acetal.Dupont™ Delrin® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.
For specifics on your requirement, please contact us for availability and pricing. Email or call 866-832-9315
We can supply both the Acetal Copolymer and the premium Dupont Delrin 150SA Homopolymer acetal from our premium suppliers: Ensinger Plastics, Z/L Plastics, Rochling Engineered Plastics and others in special formulations.
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