POM (hom.)

Polyoxymethylene is a semi-crystalline thermoplastic polymer that is also
known as polyacetal. POM is available as a homopolymer and as
copolymer with oxyethylene groups for improved thermal stability. It has
a high crystallinity, very good wear resistance and low friction coefficient,
high toughness and excellent chemical and moisture resistance.
Particularly useful in gears and snap-fit connections.

Specific properties
Density: 1.41 g/cm3

Mechanical properties: High strength and Young's Modulus and good toughness
down to -40 °C. Low creep and very good long term fatigue resistance.
Excellent dimensional stability, also in moist environments.

Thermal properties: Tg = -76 / -60 °C, Tm = 164 / 170 °C, depending on
co-monomer content, maximum use temperature 90-120 °C.
POM will decompose at high temperatures (over 238 °C).

Chemical resistance: Very good resistance to many organic liquids
(fuel, oil, brake and transmission fluids). Very low water absorption and
good resistance to strong alkalis (copolymers), but less resistance to
strong acids.

Colour/surface
White, slightly translucent. Can easily be coloured. Low gloss effect,
soft touch grades available for automotive interior applications.

Processing
Injection mouldable using a melt temperature of 180 °C to max. 230 °C.
Mould temperature between 50 °C and 120 °C, higher mould
temperatures lead to tougher and stiffer parts with less post-shrinkage.
POM has a relatively high shrinkage (around 2 %) due to the high
crystallinity.
POM can be painted and welded with various methods, but bonding
does not lead to strong interfaces due to the good chemical resistance.

Applications
-Consumer: Gears, springs and bearings in domestic appliances,
printers and hand tools, toys, shower heads, electrical tooth brush,
clock and watch components, tea/coffee/espresso machines.
-Transport: Fuel caps, fuel pumps and fuel lines in cars, windshield
wiper components, heating and air conditioning control systems,
handles, loudspeaker grilles, suspension stabiliser links and seat
belt components.
-Industry: Gears, pumps, irrigation equipment, valves, pipe
couplings, conveyor links.
-Medical: Insulin syringe, powder inhaler.