Summary
- PP is rated better with
- Phenols (+79 points); Mineral acids (+65 points); Organic acids (+63 points); Oxidising agents and halogens (+29 points); Alkalis (+24 points); Salts and salt solutions (+23 points)
- Acetal (POM) is rated better with
- Aromatic hydrocarbons (+86 points); Halogenated hydrocarbons (+76 points); Fuels, mineral oils and aliphatic hydrocarbons (+33 points); Vegetable and animal oils, fats, essential oils (+25 points); Esters and ethers (+25 points); Ketones and aldehydes (+22 points)
- Within 10 points of each other
- Alcohols and glycols; Amines and nitrogen compounds; Foods and beverages
Points are the difference in the share of rows rated A or B.
The two materials
PP
Polypropylene
Polypropylene resists most acids, alkalis and salt solutions. Concentrated oxidising acids, chlorinated solvents and aromatic hydrocarbons attack it, and it turns brittle below about 0 °C.
Rated rows: 978. A 66 %, B 11 %, C 15 %, D 8 %
Acetal (POM)
Polyoxymethylene (acetal)
Acetal (POM) resists many organic solvents and fuels. Strong acids and oxidising agents degrade it.
Rated rows: 956. A 41 %, B 32 %, C 12 %, D 15 %
Share of rows rated A or B, by chemical class
How often the two ratings agree
Chemical classes were assigned by this site, not by the source. Mixtures and trade products without a clear class are not counted.
By chemical class
| Chemical class | PP: rated A or B | Acetal (POM): rated A or B |
|---|---|---|
| Mineral acids | 70 % (63 rows) | 5 % (63 rows) |
| Organic acids | 97 % (64 rows) | 34 % (64 rows) |
| Alkalis | 100 % (22 rows) | 76 % (21 rows) |
| Salts and salt solutions | 99 % (198 rows) | 76 % (197 rows) |
| Oxidising agents and halogens | 72 % (61 rows) | 43 % (63 rows) |
| Alcohols and glycols | 93 % (59 rows) | 96 % (57 rows) |
| Phenols | 79 % (14 rows) | 0 % (14 rows) |
| Ketones and aldehydes | 69 % (35 rows) | 91 % (35 rows) |
| Esters and ethers | 63 % (71 rows) | 88 % (68 rows) |
| Amines and nitrogen compounds | 79 % (39 rows) | 74 % (38 rows) |
| Aromatic hydrocarbons | 14 % (14 rows) | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 63 % (78 rows) | 96 % (73 rows) |
| Vegetable and animal oils, fats, essential oils | 75 % (48 rows) | 100 % (45 rows) |
| Halogenated hydrocarbons | 4 % (70 rows) | 80 % (70 rows) |
| Foods and beverages | 100 % (46 rows) | 100 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 286 in total, the first 40 shown.
| Chemical | Concentration | PP | Acetal (POM) |
|---|---|---|---|
| Acetic Acid | 100 % | A | D |
| Acetic Acid | 90 % | A | D |
| Aluminum Chloride | solid | A | D |
| Aluminum Chloride | saturated | A | D |
| Ammonium Bifluoride | 50 % | A | D |
| Antimony Pentachloride | A | D | |
| Antimony Trichloride | 90 % | A | D |
| Antimony Trichloride | anhydrous | A | D |
| Antimony Trichloride | aqueous | A | D |
| Arsenic Acid | A | D | |
| Arsenic Acid | aqueous | A | D |
| Arsenic Pentoxide | A | D | |
| Battery Acid | 38 % | A | D |
| Benzyl Alcohol | D | A | |
| Bismuth Chloride | A | D | |
| Bisulfite Liquor | A | D | |
| Bisulfite Liquor with SO2 | saturated | A | D |
| Bromobenzene | D | A | |
| Bromomethane | technical grade | D | A |
| Butene | technical grade | D | A |
| Butylphenol | 100 % | A | D |
| Calcium Bisulfite | saturated | A | D |
| Calcium Bisulfite | aqueous | A | D |
| Calcium Hypochlorite | A | D | |
| Chloric Acid | 20 % | A | D |
| Chloroacetic Acid | A | D | |
| Chloroacetic Acid | 50 % | A | D |
| Chlorodifluoromethane | D | A | |
| Chloromethane (Methyl Chloride) | technical grade | D | A |
| Chromic Acid | 10 % | A | D |
| Dichloroacetic Acid | 50 % | A | D |
| Dichloroacetic Acid | technical grade | A | D |
| Dichlorodifluoromethane (R-12) | D | A | |
| Dichlorodifluoromethane (R-12) | technical grade | D | A |
| Dichlorofluoromethane | 100 % | D | A |
| Diethyl Ether | technical grade | D | A |
| Diphenyl Ether | D | A | |
| Diphyl | D | A | |
| Fluorosilicic Acid | 32 % | A | D |
| Formic Acid | 50 % | A | D |
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
More comparisons
Frequently Asked Questions
Is PP or Acetal (POM) more chemical-resistant?
Of 953 chemicals rated for both materials at 20 °C, PP and Acetal (POM) share the same rating in 391 rows (41 %). PP is rated better in 379 rows and Acetal (POM) in 183 rows.
How do PP and Acetal (POM) compare for chemical resistance?
Based on 953 chemicals tested for both: PP is rated better with Phenols, Mineral acids, Organic acids, Oxidising agents and halogens. Acetal (POM) is rated better with Aromatic hydrocarbons, Halogenated hydrocarbons, Fuels, mineral oils and aliphatic hydrocarbons, Vegetable and animal oils, fats, essential oils. They perform similarly with Alcohols and glycols, Amines and nitrogen compounds, Foods and beverages.
About this data
The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.
A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.