Summary
- PTFE is rated better with
- Phenols (+100 points); Mineral acids (+95 points); Organic acids (+66 points); Oxidising agents and halogens (+57 points); Amines and nitrogen compounds (+26 points); Salts and salt solutions (+24 points); Alkalis (+24 points); Halogenated hydrocarbons (+20 points); Esters and ethers (+12 points)
- Within 10 points of each other
- Alcohols and glycols; Ketones and aldehydes; Aromatic hydrocarbons; Fuels, mineral oils and aliphatic hydrocarbons; Vegetable and animal oils, fats, essential oils; Foods and beverages
Points are the difference in the share of rows rated A or B.
The two materials
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 %
PTFE
Polytetrafluoroethylene
PTFE is resistant to almost every chemical in this list. The known exceptions are molten alkali metals, elemental fluorine and some fluorinating agents at elevated temperature.
Rated rows: 981. A 98 %, B 2 %, C 0 %, D 0 %
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 | Acetal (POM): rated A or B | PTFE: rated A or B |
|---|---|---|
| Mineral acids | 5 % (63 rows) | 100 % (63 rows) |
| Organic acids | 34 % (64 rows) | 100 % (64 rows) |
| Alkalis | 76 % (21 rows) | 100 % (22 rows) |
| Salts and salt solutions | 76 % (197 rows) | 100 % (198 rows) |
| Oxidising agents and halogens | 43 % (63 rows) | 100 % (63 rows) |
| Alcohols and glycols | 96 % (57 rows) | 100 % (58 rows) |
| Phenols | 0 % (14 rows) | 100 % (14 rows) |
| Ketones and aldehydes | 91 % (35 rows) | 100 % (35 rows) |
| Esters and ethers | 88 % (68 rows) | 100 % (74 rows) |
| Amines and nitrogen compounds | 74 % (38 rows) | 100 % (39 rows) |
| Aromatic hydrocarbons | 100 % (14 rows) | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 96 % (73 rows) | 100 % (78 rows) |
| Vegetable and animal oils, fats, essential oils | 100 % (45 rows) | 100 % (48 rows) |
| Halogenated hydrocarbons | 80 % (70 rows) | 100 % (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: 261 in total, the first 40 shown.
| Chemical | Concentration | Acetal (POM) | PTFE |
|---|---|---|---|
| Acetic Acid | 100 % | D | A |
| Acetic Acid | 90 % | D | A |
| Acetyl Chloride | 100 % | D | A |
| Aluminum Chloride | solid | D | A |
| Aluminum Chloride | saturated | D | A |
| Ammonium Bifluoride | 50 % | D | A |
| Antimony Trichloride | 90 % | D | A |
| Antimony Trichloride | anhydrous | D | A |
| Antimony Trichloride | aqueous | D | A |
| Aqua Regia | D | A | |
| Arsenic Acid | D | A | |
| Arsenic Acid | aqueous | D | A |
| Arsenic Pentoxide | D | A | |
| Battery Acid | 38 % | D | A |
| Benzenesulfonic Acid | saturated | D | A |
| Bismuth Chloride | D | A | |
| Bisulfite Liquor | D | A | |
| Bisulfite Liquor with SO2 | saturated | D | A |
| Bromic Acid | concentrated | D | A |
| Bromine | D | A | |
| Bromine Vapors | D | A | |
| Bromine Water | saturated | D | A |
| Bromoform | D | A | |
| Butylphenol | 100 % | D | A |
| Butyric Acid | D | A | |
| Calcium Bisulfite | saturated | D | A |
| Calcium Bisulfite | aqueous | D | A |
| Calcium Hypochlorite | D | A | |
| Calcium Hypochlorite | aqueous | D | A |
| Chloric Acid | 10 % | D | A |
| Chloric Acid | 20 % | D | A |
| Chlorine | 10 % wet | D | A |
| Chlorine | 97 % | D | A |
| Chlorine Gas | D | A | |
| Chlorine Water | D | A | |
| Chloroacetic Acid | D | A | |
| Chloroacetic Acid | 50 % | D | A |
| Chloroform | 100 % | D | A |
| Chlorosulfonic Acid | technical grade | D | A |
| Chromic Acid | 10 % | D | A |
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 Acetal (POM) or PTFE more chemical-resistant?
Of 953 chemicals rated for both materials at 20 °C, Acetal (POM) and PTFE share the same rating in 390 rows (41 %). Acetal (POM) is rated better in 3 rows and PTFE in 560 rows.
How do Acetal (POM) and PTFE compare for chemical resistance?
Based on 953 chemicals tested for both: Acetal (POM) is rated better with –. PTFE is rated better with Phenols, Mineral acids, Organic acids, Oxidising agents and halogens. They perform similarly with Alcohols and glycols, Ketones and aldehydes, Aromatic hydrocarbons, Fuels, mineral oils and aliphatic hydrocarbons.
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.