POLYACETALS
PolyacetalS (POM)
Polyacetals (POM), also called polyoxymethylene or polyformaldehyde, are semi-crystalline thermoplastics formed by the polymerization of formaldehyde.
Both pure homopolymers (POM-H) and co-polymers (POM-C) are commonly used. In the case of co-polymers, ring ethers are incorporated into the POM molecular chain which particularly improve the chemical resistance in the alkaline range and the hydrolysis resistance.
POM basically have good stiffness and hardness and barely absorbs water. They have good sliding properties, and their electrical or dielectric properties are quite independent of humidity and temperature. POM is food-compatible and is offered in special, biocompatible grades.
POM can easily be processed thermoplastically and are often used as a semi-finished product for machining, as they are dimensionally stable, show good chip breakage and allow high surface qualities. Due to their recovery behavior, POM like to use for so-called "snap-fit" connections, i.e. elements that snap/fit into a suitable counterpart.
Main features
- good mechanical properties
- high resilience
- heat resistant up to 100°C
Due to their universal properties, POM is used in bulk without being reinforced. Nevertheless, various modifications are available. Especially for tribological applications there are types optimized with solid lubricants.
POM Co-Polymers
POM-C has established itself as the standard because of its good processability. In contrast to POM-H, the material is more resistant to hydrolysis, thermal oxidative degradation and chemical alkalis. Overall, POM-C tends to have lower microporosity than POM-H with large cross-sections.
Type |
DIN-Designation |
Description |
Data Sheet
|
FDA |
Acetron® C |
POM-C |
standard type
|
PDF
|
PDF
|
Acetron® C-TF |
POM-C TF20 |
with PTFE powder
|
PDF |
-
|
Acetron® C-GF |
POM-C GF25 |
reinforced with glass fiber
|
PDF |
-
|
Acetron® MD |
POM-C |
magnetic detectable |
PDF |
PDF
|
Acetron® AST |
POM-C |
antistatic |
PDF |
-
|
Semitron® ESD 225 |
POM-C |
electrostatic dissipative |
PDF |
-
|
POM Homo-Polymers
POM-H is usually made from the original raw material Delrin®. The material has slightly better mechanical properties than POM-C. In addition, the coefficient of thermal expansion is somewhat lower and the wear resistance higher than for POM-C.
Type |
DIN-Designation |
Discription |
Data Sheet
|
FDA |
Acetron® H |
POM-H |
standard type
|
PDF |
- |
Acetron® H-AF |
POM-H TF15 |
with PTFE fibers
|
PDF |
- |
FDA = suitable for food contact according to FDA
Components made of natural-colored Acetron® C and Acetron® MD can be delivered with statement of suitability for contact with food according to Regulation (EC) 1935/2004.
Information on the available semi-finished product dimensions is available here!
Back to the overview of engineering plastics click here!
