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®.
Next time you are cutting vegetables on your cutting board, the material most likely to be used is Polyethylene. Because it is stain, moisture and odor resistant, Polyethylene is a perfect choice. Other cutting boards made out of wood are more susceptible to bacteria and odors because they lack the properties that Polyethylene sheets offer, such as its chemical resistance and FDA approval for food contact. Polyethylene is a very durable and lightweight material that comes in many forms and is a great for a wide variety of applications.
NSF Approved Cutting Boards
The HDPE is available in .500″ thick in several FDA / NSF approved colors, and is great for use in kitchens where cross contamination is a problem.
The Ultimate Cutting Board
Polyethylene has many names. The most common are HDPE, LDPE, and UHMW. The difference has to with the molecular weight and branching which is when a monomer or atom is replaced by a longer chain of polymers (a long repeating chain of atoms). High Density is commonly used for milk jugs and food containers. Low Density is commonly used for bottles and plastic bags. UHMW, which has higher molecular weight (2-6 million) allows for an even transfer over the length of material which makes it stronger and able to be used for bearing applications due to its great wear resistance. Commonly used in the food and dairy industry, UHMW is a great replacement for other materials and solution to many problems. All of these polymers are derived from the same family but all have certain properties that make them a little different. HDPE provides great chemical resistance, with high impact strength and great energy absorption. LDPE has most of the same properties as High Density but is not as dense at 9.15, opposed to HDPE which is 9.34. It also has a lower tensile strength and easier formability.
UHMW is a strong material that has great durability and low co-efficient making it an ideal for sliding applications. Polyethylene offers a wide range of material choices and properties and has great durability that can be suitable for a number of applications. From the food industry to automotive, the kitchen or the warehouse, whatever your Polyethylene needs are; High Density, Low Density or UHMW, Polyethylene is a great choice.
Typical Resin Properties:
General Property
ASTM Test
Typical Value HDPE
Typical Value LDPE
Typical Value UHMW
Specific Gravity
D792
.941 – .965
.91 – .925
.93 – .94
Tensile Strength Yield
D638
3,800 – 5,500
1,400 – 2,000
6,800
Izod Impact – Notched
D256
2.0 – 3.5
>16
No Break
Vicat Softening Temp
D1525
257ºF
219ºF
260
Hardness – Rockwell
D785
D60 -70
D42 – 50
R64
Continuous Use Temp
–
-100 – 180ºF
174ºF
180ºF
Deflection Temp @ 66 psi
D648
171
124
174
Co. Thermal Expansion
D696
7X10-5
4.6 -5.5X10-5
11.0X10-5
Please contact us for more information on FDA and NSF approved plastic materials. Email us here, or call us at: 866-832-9315
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
A newly released form of Filled PEEK is now available. This PEEK is filled with PTFE and is called Unitrex Lf20, and it is filled with 20% PTFE. This new grade of PTFE Filled PEEK plastic was originally produced by Nytef Plastics. It is an extruded thermoplastic that comes in both rod and sheet form. This grade has significantly improved properties over the standard unfilled grades of PEEK. The PTFE filler provides excellent wear properties and has a very low co-efficient of friction, which makes this a great material for sliding and wear applications, and is made to last for long periods of abuse. Unitrex Lf20 has great machinability and dimensionally stability. It has a wide range of uses in such fields as medical, semi-conductor, and aerospace seals, where standard PEEK is too rigid. These properties enable this material to replace Polyimide (Vespel®) and PCTFE (formerly Kel-F) in many applications of high chemical resistance and the ductility for use in seals. This Filled PEEK works extremely well in Medical, Semi-Conductor and Aerospace Seal applications.
PTFE Filled PEEK vs. PTFE Filled Acetal
Comparable to Lf13 which is 13% PTFE filled Delrin® (Delrin® AF), which is also good for most of the same types of applications but cannot withstand the high temperatures than that of Unitrex Lf20. The PTFE Filled PEEK has a melting point of 650 degrees F while the PTFE Filled Delrin® – Unital® Lf13 has a melt point of 347 degrees F, making both materials high temperature plastics.
Because the Nytef Unitrex Lf20 is filled with PTFE (which has the lowest co-efficient of friction of any plastic), it is ideal for sliding and wear applications. It also has a kinetic and static friction resistance of 0.1 which makes it the perfect choice for jobs were heat from friction should not be generated and part longevity is critical. Unitrex Lf20 offers superior properties to many other plastics, such as high heat and chemical resistance but also great friction resistance along with improved properties to make it a great plastic for a wide spectrum of uses.
Why Change from Vespel SP-1 or PCTFE to Unitrex Lf20?
While this new PTFE Filled PEEK will not replace the Vespel SP-1 and PCTFE in all applications, it certainly will in many applications (see table for comparison). The main reason to make a change is, drum roll please, COST. The Unitrex Lf20 is up to 30% less expensive that the other materials. With similar and comparable properties, consider making the change.
Unitrex® Lf20 also exhibits a far superior chemical resistance to that of its Acetal counterpart due to PEEK having a far better range of chemical resistance to aqueous and organic environments as well as acids and alkalines. Acetal Copolymer tends to degrade when exposed to such chemicals like sulfuric acid and chlorine while PEEK only tends to be attacked by halogens and hydrocarbons such as in crude oils. For additional properties and to compare the Unitrex LF-20 to Dupont Vespel SP-1 and PCTFE see the table below. Here is a copy of the full data sheet on Nytef Unitrex Lf20.
Standard Properties Table
Properties
TestMethod
Unit
UnitrexLF20 Nominal Value
PCTFE(Kel-f) Nominal Value
VespelSP-1 Nominal Value
Specific Gravity
ASTM-D-792
1.42
2.1 – 2.14
1.43
Tensile Strength
ASTM-D-638
psi
11,500
4,800 – 5,300
12,500
Tensile Modulus
ASTM-D-638
psi
460,000
207,000
–
Flexural Modulus
ASTM-D-790
psi
500,000
180,000
450,000
Rockwell Hardness
ASTM-D-785
84-D
90-D
45 – 60 E
Melting Point
DSC
degress F
650
410 – 415
680+
Flammability
UL 94
@ 3.0mm
V-0
V-0
V-0
Kinetic Coef. of Friction
ASTM-D-1894
0.1
–
–
Static Coef. of Friction
ASTM-D-1894
0.1
–
–
For additional details on these and other materials, please contact us here or call us at 866-832-9315
Unitrex and Unital are registered trademarks of Polymer Industries Delrin and Vespel are registered trademarks of E.I. Dupont
Is colored Acetal Copolymer – Delrin® Homopolymer Rod Readily Available?
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.
