Summary
- FEP is rated better with
- Mineral acids (+80 points); Ketones and aldehydes (+79 points); Oxidising agents and halogens (+71 points); Halogenated hydrocarbons (+58 points); Alkalis (+55 points); Esters and ethers (+43 points); Organic acids (+30 points); Amines and nitrogen compounds (+22 points)
- Within 10 points of each other
- Salts and salt solutions; Alcohols and glycols; 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
PETG
Polyethylene terephthalate glycol (co-polyester)
PETG is a co-polyester for clear containers. Strong acids and alkalis and most organic solvents attack it.
Rated rows: 619. A 55 %, B 23 %, C 4 %, D 18 %
FEP
Fluorinated ethylene propylene
FEP has nearly the chemical resistance of PTFE and can be melt-processed. Its service temperature, about 200 °C, is lower than that of PTFE.
Rated rows: 908. A 99 %, B 0 %, C 1 %, 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 | PETG: rated A or B | FEP: rated A or B |
|---|---|---|
| Mineral acids | 20 % (41 rows) | 100 % (55 rows) |
| Organic acids | 70 % (33 rows) | 100 % (64 rows) |
| Alkalis | 45 % (20 rows) | 100 % (18 rows) |
| Salts and salt solutions | 100 % (159 rows) | 100 % (197 rows) |
| Oxidising agents and halogens | 29 % (38 rows) | 100 % (52 rows) |
| Alcohols and glycols | 100 % (40 rows) | 100 % (57 rows) |
| Phenols | – | 100 % (14 rows) |
| Ketones and aldehydes | 21 % (24 rows) | 100 % (33 rows) |
| Esters and ethers | 57 % (28 rows) | 100 % (69 rows) |
| Amines and nitrogen compounds | 78 % (9 rows) | 100 % (38 rows) |
| Aromatic hydrocarbons | – | 100 % (14 rows) |
| Fuels, mineral oils and aliphatic hydrocarbons | 98 % (65 rows) | 100 % (74 rows) |
| Vegetable and animal oils, fats, essential oils | 100 % (34 rows) | 100 % (47 rows) |
| Halogenated hydrocarbons | 32 % (25 rows) | 90 % (49 rows) |
| Foods and beverages | 100 % (43 rows) | 100 % (46 rows) |
Where the ratings differ most
Rows where the two ratings at 20 °C are at least two grades apart: 121 in total, the first 40 shown.
| Chemical | Concentration | PETG | FEP |
|---|---|---|---|
| 1,2-Dibromoethane | D | A | |
| Acetaldehyde | 40 % | D | A |
| Acetaldehyde | technical grade | D | A |
| Acetic Acid | 100 % | D | A |
| Acetic Acid | 90 % | D | A |
| Acetone | D | A | |
| Acetonitrile | D | A | |
| Acetyl Chloride | 100 % | D | A |
| Acrylonitrile | D | A | |
| Allyl Acetate | 100 % | D | A |
| Allyl Chloride | 100 % | D | A |
| Battery Acid | 38 % | D | A |
| Benzaldehyde | D | A | |
| Benzene | D | A | |
| Benzenesulfonic Acid | saturated | D | A |
| Bitter Almond Oil | D | A | |
| Bromine | D | A | |
| Bromine Vapors | D | A | |
| Bromoform | D | A | |
| Chloral Hydrate | technical grade | 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 |
| Chromic Acid | 20 % | D | A |
| Chromic Acid | 50 % | D | A |
| Cresol | D | A | |
| Cyclohexanone | technical grade | D | A |
| Dichloroacetic Acid | 50 % | D | A |
| Dichloroacetic Acid | technical grade | D | A |
| Dichloroethylene | technical grade | D | A |
| Dichloromethane | D | A | |
| Dichloropropane | 100 % | D | A |
| Diethyl Ketone | D | A | |
| Diisobutyl Ketone | technical grade | D | A |
| Diisopropyl Ketone | D | A | |
| Diphenyl Ether | 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 PETG or FEP more chemical-resistant?
Of 592 chemicals rated for both materials at 20 °C, PETG and FEP share the same rating in 332 rows (56 %). PETG is rated better in 1 rows and FEP in 259 rows.
How do PETG and FEP compare for chemical resistance?
Based on 592 chemicals tested for both: PETG is rated better with –. FEP is rated better with Mineral acids, Ketones and aldehydes, Oxidising agents and halogens, Halogenated hydrocarbons. They perform similarly with Salts and salt solutions, Alcohols and glycols, Fuels, mineral oils and aliphatic hydrocarbons, Vegetable and animal oils, fats, essential oils.
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.