Acetal (PolyOxy-Methylene) Specifications
GENERAL PROPERTIES
 Acetal is the common name for a family of thermoplastics with the chemical
name "PolyOxy-Methylene". Acetal is available in a general purpose copolymer
grade, a homopolymer version (Delrin ®), and
several filled Delrin ® grades. Acetal provides
high strength and stiffness, enhanced dimensional stability, and is easy to
machine. As a semi-crystalline material, acetal is characterized by a low
coefficient of friction and good wear properties. ( see also
Pomalux Static-Control Acetal
and
Semitron ESd 225 Static-Dissipative Acetal
)
FEATURES
• High strength, stiffness, dimensional stability • Very low moisture
absorption • Good wear and abrasion resistance • Wide range chemical
resistance (including many solvents)
ACETAL GRADES
ACETAL COPOLYMER (unfilled)
The copolymer grade offers excellent performance at a slightly lower cost
than Delrin ®. Acetal copolymer may exhibit center
line porosity, but porosity-free material is available. Certain grades are
FDA, USDA, NSF, Canada AG and 3-A Dairy compliant. Low stress levels and
high strength assure flatness and dimensional stability up to a maximum
continuous service temperature of 180°F (80°C). Acetal copolymers are
available in a wide variety of colors, including
RED ,
ORANGE , YELLOW
, GREEN ,
BLUE , VIOLET
, BLACK, WHITE & NATURAL .
DELRIN ® (unfilled)
Delrin ® acetal homopolymer offers slightly higher
mechanical properties than acetal copolymer, but may contain a low density
center (also known as "center line porosity") especially in large
cross-sections. The homopolymer also gives slightly less chemical resistance
than copolymer acetal. For example, Delrin ® is
ideal for small diameter, thin-walled bushings that benefit from the
additional strength and rigidity of homopolymer acetal. Delrin ®
is available BLACK & NATURAL colors.
NOTE: In 2002, DuPont
Company discontinued production of Delrin ® II
550SA resin ... this has been replaced by Delrin ®
511P. For more details use these links to view our .PDF files:
Letter of Explanation •
Delrin 511P resin datasheet •
Delrin II 550SA resin datasheet
DELRIN ® AF (PTFE-filled)
This material is manufactured from Delrin ®
homopolymer resin which has been uniformly filled with a dispersion of PTFE
fibers. Delrin
® AF is a unique thermoplastic material for use in
moving parts in which low friction and long wear life are important. It
retains 90% of the mechanical strength of unfilled acetal homopolymer, while
offering very low friction and almost no "slip-stick" behavior. Delrin
®
AF is BROWN in color.
TYPICAL PROPERTIES of ACETALS
|
| ASTM or UL test |
Property |
Acetal
Copolymer |
Delrin ®
Homopolymer |
Delrin ® AF
PTFE-filled |
| PHYSICAL |
| D792 |
Density (lb/in³)
(g/cm³) |
0.051
1.41 |
0.051
1.41 |
0.054
1.50 |
| D570 |
Water Absorption, 24 hrs (%) |
0.2 |
0.2 |
0.2 |
| MECHANICAL |
| D638 |
Tensile Strength (psi) |
9,500 |
11,000 |
8,000 |
| D638 |
Tensile Modulus (psi) |
400,000 |
450,000 |
435,000 |
| D638 |
Tensile Elongation at Break (%) |
30 |
30 |
15 |
| D790 |
Flexural Strength (psi) |
12,000 |
13,000 |
12,000 |
| D790 |
Flexural Modulus (psi) |
400,000 |
450,000 |
435,000 |
| D695 |
Compressive Strength (psi) |
15,000 |
16,000 |
16,000 |
| D695 |
Compressive Modulus (psi) |
400,000 |
450,000 |
350,000 |
| D785 |
Hardness, Rockwell |
M88 / R120 |
M89 / R122 |
M85 / R115 |
| D256 |
IZOD Impact Notched (ft-lb/in) |
1.0 |
1.0 |
0.7 |
| THERMAL |
| D696 |
Coefficient of Linear Thermal Expansion
(x 10 -5 in./in./°F) |
5.40 |
4.70 |
5.00 |
| D648 |
Heat Deflection Temp (°F / °C)
at 264 psi |
220 / 104 |
250 / 121 |
244 / 118 |
| D3418 |
Melting Point Temp (°F / °C) |
335 / 168 |
347 / 175 |
347 / 175 |
| - |
Max Operating Temp (°F / °C) |
180 / 82 |
180 / 82 |
180 / 82 |
| C177 |
Thermal Conductivity
(BTU-in/ft²-hr-°F)
(x 10 -4 cal/cm-sec-°C) |
1.6
5.5 |
2.5
8.6
|
-
|
| UL94 |
Flammability Rating |
HB |
HB |
HB |
| ELECTRICAL |
| D149 |
Dielectric Strength (V/mil) short time, 1/8" thick |
420 |
450 |
400 |
| D150 |
Dielectric Constant at 1 MHz |
3.8 |
3.7 |
3.1 |
| D150 |
Dissipation Factor at 1 MHz |
0.005 |
0.005 |
0.010 |
| D257 |
Volume Resistivity (ohm-cm) at 50% RH |
10 15 |
10 15 |
3.0 x 10 16 |
NOTE: The information contained herein are typical values intended
for reference and comparison purposes only. They should NOT be used as a
basis for design specifications or quality control. Contact us for
manufacturers' complete material property datasheets.
All values at 73°F (23°C) unless otherwise noted.
DELRIN is a registered trademark of DuPont
|
