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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)

Why You Should Use Homopolymer Acetal or Acetal Copolymer Rod

Why You Should Use Homopolymer Acetal or Acetal Copolymer Rod

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. Dupont is the maker of Dupont Delrin® resins

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 PropertyASTM
Test
Typical Value
Unfilled

Homo-Polymer
Typical Value
Unfilled Co-Polymer
Specific Gravity D7921.421.40
Tensile Strength YieldD6389,600 – 11,0009,000 – 10,200
Tensile ModulusD638450,000400,000
Izod Impact – NotchedD2561.21.0
Hardness – RockwellD785M94M90
Deflection Temp @ 264psiD648257220
Deflection Temp @ 66 psiD648347335
Water Absorption @ 24 hrs
%0.240.25
Co. Thermal ExpansionD6966.83X10-55.4X10-5

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.Comparing Dupont Delrin to Acetal Copolymer

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

Large Plastic Sheet and Plastic Rods from Gehr Plastics

Large Plastic Sheet and Plastic Rods from Gehr Plastics

Large engineering plastic from Gehr Plastics

One of our secret claims to fame

Since 1975 we have provided large diameter plastic rods and thick plastic sheets, plates, slabs and blocks. One of our long time ‘secret’ sources has been Gehr Plastics. Since 1932 the Gehr family has owned and operated the Gehr Plastics company. They are a worldwide leader in semi-finished plastic shapes in thermoplastics, primarily sheet and rod. The headquarters for Gehr Plastics is in Mannheim, in south western Germany. For almost 30 years, Gehr Plastics has had production facilities in the Philadelphia area, providing the USA with the same high quality plastic shapes. When we mention large diameter rod, we mean it! Gehr can produce plastic rod up to almost 20″ diameter in several grades of plastic. They also produce sheet plastics up to 8″ thick, and make the largest materials of most manufacturers of plastic sheets and rods.

At Gehr Plastics, Quality Engineering Plastic Comes First

Our first purchases with Gehr Plastics was in the PVC rod family. Once again, they make huge cross sections in many materials, including the PVC rod. Many manufacturers struggle with large sections of PVC rod because keeping it void free throughout the large diameter is very difficult. Not for Gehr Plastics, they specialize in engineering plastic materials. We have chosen this high quality manufacture for their exceptional product quality. We know the demands of our client base, and only choose the best factories to supply our products. Gehr is definitely one of the premier plastics producers in the world. While the quality of the PVC rod is excellent, the rest of the Gehr Plastics product line is also some of the best plastic semi-finished shapes available in the market place. Here is a list of some of the many materials that Gehr Plastic produces:

Large 14" Diameter Polypropylene rods

14 inch Natural Polypropylene Rod produced by Gehr Plastics, the largest domestic plastic rod currently in production. 12″ diameter UHMW rod from Roechling Plastics, Industrial Plastic Supply is master distributor for both of these manufacturers.

Many of the above items are also available in sheets, plates, slabs or blocks.

Gehr Plastics – one of our engineering plastic partners

We have been proud to offer the complete line of plastic rod, sheet, slab, plate and block from Gehr Plastics, and consider them a highly valued partner in supplying these engineering plastic materials to you, our valued client. For more information on the size range, availability and pricing on these and other plastic materials, click here or call us at 866-832-9315

Topic: Gehr Plastics – Supplier of engineering plastic materials