| Chemical Resistance of POM | ||||||
| Chemical Name | Test ConditionsVariety | Variety,% | ||||
Time, Month | Temperature,℃ | Tensile Strength | Quality | |||
POM | Acetal Copolymer | POM | Acetal Copolymer | |||
| Ammonia（10%） | 3 6 | 23 23 | U① | NC② | U | 0.88 |
| Hydrochloric Acid（10%） | 3 6 | 23 23 | U | U | U | U |
| Sodium Hydroxide（40%） | 12 | 23 | U | -2 | U | 0.73 |
| Acetic Acid（6%） | 12 | 23 | NC | 0.6 | 0.8 | 1.13 |
| Acetone | 12 | 23 | -5 | -17 | 4.9 | 3.7 |
| Benzene | 9 6 | 60 49 | -11 | -17 | 4 | 3.9 |
| Carbon Tetrachloride | 12 | 23 | -3 | 2 | 1.3 | 1.4 |
| Ethyl Acetate | 12 | 23 | -7 | -17 | 2.7 | 4.2 |
| Ethanol | 12 | 23 | -5 | -6③ | 2.2 | 2.2③ |
| Brake oil（super 9） | 10 12 | 70 23 | -6 | 3 | 1.6 | 0.53 |
| Motor oil（10W30） | 12 12 | 70 23 | 3 | 5 | -0.2 | 0.04 |
| Unleaded gasoline | 8 8 | 23 40 | -2 -2 | 0.33 0.69 | ||
①U is unsatisfactory; ②NC is no change; ③95% ethanol
Polyoxymethylene resin has high resistance to oils and organic solvents (such as hydrocarbons, alcohols, ketones, esters, benzene, etc.), even at relatively high temperatures, after more than half a year of immersion, it still remains It can maintain high mechanical strength, and its mass change rate is generally below 5%.
POM resin has good resistance to dilute acid, but stress cracking will occur to strong acid, especially sulfuric acid, hydrochloric acid, nitric acid, sulfurous acid, nitrous acid, etc.
The alkali resistance of polyformaldehyde copolymer is obviously better than that of homopolyformaldehyde. This is because the homopolyoxymethylene blocked by esterification will be decomposed by water when it encounters alkali.
Butyric acid end groups, followed by sequential shedding of formaldehyde chains. Generally, homopolyoxymethylene is only safe to use in alkaline solutions with a pH value below 10.
