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
What is the difference between Noryl and PPO (or Modified PPO)?
Noryl® is a trade name for Sabic Plastics (formerly GE Plastics) for their Modified PPO (Modified PolyPhenyleneOxide). Sabic is the world leader in engineering and mechanical plastic resins.
This resin is a remarkably versatile material. PPO exhibits unusually low moisture absorption and great machinability. Noryl® is an excellent choice for water filtration and fluid handling parts. Noryl has excellent impact resistance, long term dimensional stability and is light weight. Noryl® has exceptional electrical properties (properties boosted by lack of water absorption). It can be thermoformed and machined to tight tolerances. It carries a UL flammability rating between UL 94-HB to UL 94 V-1. The primary specification covering PPO (Noryl®) is ASTM-D-4349.
Sabic Noryl is available in two standard unfilled varieties, EN-185 and EN-265. The number indicates the heat deflection temperature of the material. This material is easy to machine, holds tolerances well, and is great for water immersion applications. A complete data sheet is found here.
We stock this material in both sheet and rod. The standard natural color for Noryl is opaque Black and is stocked as the EN-265 grade of resin. Noryl® is also available as a glass filled material which enhances both the mechanical and thermal properties of the resin. Chemical attack from water, most salt solutions, acids and bases is also minimal with Noryl®.
Nylon Tube and Tubing can be made from Nylon 6 or 6/6
Nylon is one of the most popular and widely used plastic materials. From the carpet in your home to the yellow Nylon rope you have in your garage, Nylon is a tough and very wear resistant material. This self lubricating mechanical plastic material is very stiff and extremely durable. This material can be machined easily, and is a key industrial plastic resin.
Nylon 6 and Nylon 6/6 Tubing
While Nylon is a common plastic material, in the extrusion and cast grades, it is not a normal stock item for many factories. Nylon can be produced in a huge range of sizes. The cast process enables the range of sizes of a Cast Nylon Tube (Type 6) to be almost unlimited. The extrusion process is a bit more restrictive, which can produce very small sizes to larger sizes of Extruded Nylon Type 6/6 Tubing up to about 2.0″ OD. The properties of these materials are similar, and are listed here. Also, in the case of the Cast Type 6 Nylon Tube, many additives can be mixed into the casting mixture to increase many critical properties. Examples of these additives can yield: Glass Filled Nylon Tube, FDA Approved Oil Filled Cast Nylon Tubing, Cast Nylon MD Tube (molybdenum disulfide), Solid Lubricant Filled Cast Nylon Tube, and a few additional variations. These same filled items are also available in Cast Nylon Rod, Cast Nylon Sheets and Cast Nylon Plates (all made from the same Cast Nylon Type 6 resin). This casting process allows for a wide range of sizes and configurations, from round rod, cast sheet, tubular bar to near net shapes and covers on metal rollers and gears.
Why use Tubular Nylon (Nylon Tubular Bar)
There are numerous reasons to use a Nylon Tubular shaped material.1. Vast range of sizes to fit most requirements2. Large reduction of waste due to near net shape3. Great reduction of machining time due to matching size to finished needs4. Lower cost due to reduced material and reduced machining time
The difference between Nylon 6 Tubing and Nylon 6/6 Tube
The main differences are the base resin. The Nylon 6 tubing is a cast resin, and the Nylon 6/6 tube is an extrusion grade resin. Both materials are still Nylon, just a different grade of resin. The properties are also very similar, look here for specific Nylon resin properties. The other difference is that the Cast Type 6 Nylon is normally in larger sizes. This is because the cast version is poured as a liquid into molds or rigid tooling, and is done one at a time. This process, while it makes a very high quality part, is a more expensive manufacturing method, and is not cost effective in small or thin cross sections.The extrusion grade of Nylon, the Type 6/6 Nylon is heat processed in large batches. This process requires set up and large runs, and is very cost effective in these large production runs. In addition, the cross sections for the heat processed Nylon 6/6 can not be excessively large. The extruded Nylon 6/6 is therefor done sizes up to about 3″, as larger pieces are more expensive and require extra stress relieving to prevent warping.
Cast Nylon Versatility
The Cast Nylon manufacturing in the USA is very advanced. The production facilities can produce amazing and diverse sizes and shapes in the grades listed above. One of the unique versions of Cast Nylon is in the Glass Filled Nylon Tube, Glass Filled Nylon Rod and Glass Filled Nylon Sheet range. The percentage of glass fill can be custom blended to meet your specific needs, and can also contain additional fillers like MD, Oil or pigments. Many grades of Nylon are also available for very specific applications, like: bearings, sheaves, pulleys, wear plates, food processing applications, FDA approved grades, color matched for identification and many more. Other plastic materials used in these same applications include: Acetal Copolymer, PET (Polyester), PTFE and more.Contact us today for additional information on this or any other plastic sheet, rod or tube material. E-mail us here, or call us toll free at 866-832-9315, or visit our main web page at: iPlasticSupply.com
Gehr Plastics has been a major global manufacturer in the plastic sheet and rod industry since 1932. During this period, Gehr has become a leader in a variety of product lines, and also become known for very large sizes in both sheet and rod. Currently Gehr can produce Acetal rod up to 20″ in diameter and sheets up to 8″ thick. Some of the many plastic materials the Gehr produces:
Radel Rod is produced in many medical grade colors
Being innovative also means looking forward. Gehr was selected as the Bioplastics manufacturer of the year in 2008, partly for the new line of plastic materials which have a bio base. These materials have a variety of bio based forms, including: a PLA base, Cellulose based, Polyamide and Wood – Plastic Composite (WPC). One such material is ECOGEHR PLA-L which is a blend of polylactic (polylactic acid), some lignine, fatty acid and wax. This biopolymer is new to our industry and can be used in temperatures ranging from -22 °F to +140 °F.This complete line of materials is one of the only available in the plastic industry to be comprised of many renewable raw materials. Gehr leads the way in this exceptional and innovative product line.
ClearGehr Polyamide Rod
This brand new product is a Clear Polyamide rod. The outside surface is as extruded, and can be polished. This enables the production of a relatively clear sight glass quality material with most of the high end properties of Polyamide – Nylon material. We have supplied this material for small machined parts where neither Polycarbonate nor Acrylic would work well. Because of the natural inherit chemical resistance of Polyamide, this high end ClearGehr rod can out perform all normal transparent plastics. Give us a call to see if this new innovative product will work in your difficult application.
FDA Approved Wear Grade Acetal
Have you been looking for an extended wear Acetal material (like the PTFE filled Acetals – Delrin AF), but need it to be FDA approved? Then perhaps you should consider WearGehr. This proprietary filled Acetal material has excellent wear resistance, and retains the FDA approval of the base Acetal, unlike the PTFE filled Acetal materials which are not FDA approved. It is made in a blue color for easy identification, also it remains very machinable. Contact us for more information on this excellent high tech material.Call us at 866-832-9315 or send us a note here.
This question was very easy to answer, up until now.
First: what is Zytel 42? It is a Natural Nylon 6/6 extrusion grade plastic resin. An extremely popular and heavily used material for machinable and durable plastic parts. For as far back as we can find information, this Zytel 42 Nylon 6/6 resin has been used in numerous food contact and food processing machine components.
We have just received notice that Dupont will be making some changes to their formula for this Nylon grade. For years we have provided our clients with Dupont Zytel 42 Nylon resin extruded into sheet, rod and other profiles. The Dupont announcement states that the Zytel 42 will no longer have a food grade rating – FDA approval. They will produce a new resin called Zytel 42FG, which will have all the approvals we always had with the Zytel 42.
Why in the world would a company do such a thing? Our guess is that this is a cleaver way to increase prices significantly without a standard and blatant price increase. Let’s just hide it in a new resin package.
Zytel 42 – will still be available, but without the FDA approval
Zytel 42FG – the ‘new’ resin will carry the FDA approval, but at much higher price
Nylon Food Grade still available
These huge Cast Nylon Blocks 12″ X 12″ X 48″
What is the difference between the old Zytel 42 and the new Zytel 42FG? From what we have read so far, nothing. It is probably the same material, new name. The ‘new’ Zytel 42 is actually the new ‘dumbed’ down resin – they just took away the Food Grade label, maybe took out an ingredient or two, and viola, new Zytel 42 – non Food Grade Nylon.
This news has spread quickly through our industry. As mentioned above, we have provided this material in this grade for over 36 years for Food Grade/FDA Approved applications.
The main reason for this article is to get the news out the the marketplace. Engineers and designers have been specifying this resin for their applications, and now, with out much notice, the product they assume is Food Grade will no longer be acceptable for these applications. It is unclear at this point whether the extrusion plants will be producing product from both resins, or opting to use one or the other. It appears that Nylon Food Grade resins my become a special, or that all materials may becomes standard as Nylon Food Grade.
Is Nylon Food Grade Resin Important To You?
This is the question we find ourselves asking. Does the end user think of Nylon when they are looking for an FDA approved plastic? Or, do they consider Acetal Copolymer, Acetal Homopolymer, Polyethylene, and other materials first? Do you think of Nylon rod, bar, sheet and slab as mechanical materials to use when making gears, wear strips, and other non FDA applications?
Please take a moment and let us know you thoughts. We value your input – it will help us in evaluating the direction we want to go with our inventory.
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