Summary
- PVC Flexible is rated better with
- Mineral acids (+36 points); Organic acids (+26 points); Alkalis (+24 points); Salts and salt solutions (+20 points)
- Acetal (POM) is rated better with
- Ketones and aldehydes (+91 points); Alcohols and glycols (+88 points); Esters and ethers (+84 points); Halogenated hydrocarbons (+80 points); Fuels, mineral oils and aliphatic hydrocarbons (+79 points); Amines and nitrogen compounds (+74 points)
- Within 10 points of each other
- Oxidising agents and halogens; Foods and beverages
Points are the difference in the share of rows rated A or B.
The two materials
PVC Flexible
Flexible (plasticised) polyvinyl chloride
Flexible PVC shares the solvent weaknesses of rigid PVC, and any liquid that extracts the plasticiser also hardens it. It is generally less resistant than rigid PVC.
Rated rows: 344. A 45 %, B 1 %, C 17 %, D 37 %
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 | PVC Flexible: rated A or B | Acetal (POM): rated A or B |
|---|---|---|
| Mineral acids | 41 % (27 rows) | 5 % (63 rows) |
| Organic acids | 60 % (25 rows) | 34 % (64 rows) |
| Alkalis | 100 % (11 rows) | 76 % (21 rows) |
| Salts and salt solutions | 96 % (81 rows) | 76 % (197 rows) |
| Oxidising agents and halogens | 47 % (17 rows) | 43 % (63 rows) |
| Alcohols and glycols | 8 % (26 rows) | 96 % (57 rows) |
| Phenols | – | 0 % (14 rows) |
| Ketones and aldehydes | 0 % (9 rows) | 91 % (35 rows) |
| Esters and ethers | 4 % (25 rows) | 88 % (68 rows) |
| Amines and nitrogen compounds | 0 % (12 rows) | 74 % (38 rows) |
| Aromatic hydrocarbons | – | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 17 % (23 rows) | 96 % (73 rows) |
| Vegetable and animal oils, fats, essential oils | – | 100 % (45 rows) |
| Halogenated hydrocarbons | 0 % (31 rows) | 80 % (70 rows) |
| Foods and beverages | 93 % (14 rows) | 100 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 160 in total, the first 40 shown.
| Chemical | Concentration | PVC Flexible | Acetal (POM) |
|---|---|---|---|
| 1-Ethylhexanol | D | A | |
| Acetophenone | D | A | |
| Acetylene | 100 % | D | A |
| Amyl Acetate | D | A | |
| Aniline | D | A | |
| Benzaldehyde | D | A | |
| Bitter Almond Oil | D | A | |
| Bromomethane | technical grade | D | A |
| Butanetriol | 100 % | D | A |
| Butanol | technical grade | D | A |
| Butyl Glycol | 100 % | D | A |
| Chlorobenzene | D | A | |
| Chlorodifluoromethane | D | A | |
| Chloroethane (Ethyl Chloride) | D | A | |
| Chloromethane (Methyl Chloride) | technical grade | D | A |
| Chromic Acid | 20 % | A | D |
| Chromic Acid | 50 % | A | D |
| Cyclohexanol | technical grade | D | A |
| Cyclohexanone | technical grade | D | A |
| Dibutyl Phthalate (DBP) | D | A | |
| Dichlorodifluoromethane (R-12) | D | A | |
| Dichlorodifluoromethane (R-12) | technical grade | D | A |
| Dichlorofluoromethane | 100 % | D | A |
| Diethyl Ether | technical grade | D | A |
| Dioxane | D | A | |
| Diphenyl Ether | D | A | |
| Epichlorohydrin | 100 % | D | A |
| Ethyl Acetate | 100 % | D | A |
| Ethyl Glycol | 100 % | D | A |
| Ethylbenzene | D | A | |
| Ethylene Dichloride | D | A | |
| Ethylenediamine | technical grade | D | A |
| Formamide | technical grade | D | A |
| Formic Acid | 98-100 % | A | D |
| Furfuryl Alcohol | technical grade | D | A |
| Hydrocyanic Acid (Hydrogen Cyanide) | technical grade | A | D |
| Hydrocyanic Acid (Hydrogen Cyanide) | aqueous | A | D |
| Iodine Tincture | D | A | |
| Ferric Chloride (Iron(III) Chloride) | saturated | A | D |
| Isobutyl Acetate | 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 PVC Flexible or Acetal (POM) more chemical-resistant?
Of 336 chemicals rated for both materials at 20 °C, PVC Flexible and Acetal (POM) share the same rating in 108 rows (32 %). PVC Flexible is rated better in 86 rows and Acetal (POM) in 142 rows.
How do PVC Flexible and Acetal (POM) compare for chemical resistance?
Based on 336 chemicals tested for both: PVC Flexible is rated better with Mineral acids, Organic acids, Alkalis, Salts and salt solutions. Acetal (POM) is rated better with Ketones and aldehydes, Alcohols and glycols, Esters and ethers, Halogenated hydrocarbons. They perform similarly with Oxidising agents and halogens, 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.