Scientific name

Polyformaldehyde

Colour

POM is a dense and smooth light yellow or white material with a high surface hardness and high gloss. The thin-walled part becomes semi transparent. It is a crystalline polymer with high crystallinity.

Combustion characteristics

Flammable and can continue to burn after leaving the flame. The upper end of the flame is golden yellow and the lower end is blue. During combustion, molten droplets occur and a strong pungent odor of formaldehyde is emitted.

Advantages

The biggest advantage of POM is its high surface hardness and density, low wear, fatigue and impact resistance, low friction coefficient, and self-lubricating. Therefore, it is the preferred material for manufacturing gears. POM has high mechanical strength and rigidity. Although it has a high shrinkage rate, its size is stable. POM has good dielectric properties, solvent resistance, and no stress cracking. POM is resistant to torsion and immediately returns to its original state after external force is removed.

Disadvantages

The biggest drawback of POM is its inability to withstand high temperatures and poor thermal stability. POM is not resistant to light exposure, including visible and invisible light. POM has poor acid resistance and is not resistant to acid erosion.

Injection molding performance

POM is a crystalline plastic with a clear melting point. It melts at 175 ℃ and decomposes at 240 ℃. The general processing temperature is 190 ℃ -220 ℃. Its processing range is very narrow; It does not absorb water and generally does not require drying during injection molding. However, products with high quality requirements can be dried at 60 ℃ for 1-2 hours. The temperature should not be too high, otherwise non dyed products will change color. It has poor acid resistance and cannot be dyed with acidic dyes. When changing the material washing machine, PP and PE should be used as intermediate carriers.

Applications

Production of gears, springs, bearings, shaft sleeves, connecting rods, impellers, and blades.