Chemical resistance of filaments
One of the first things you will start with before you start printing on your 3D printer will be choosing your filament. This is a basic and important step, because it does not end with printing the model. And now we come to the important questions - will the print be functional or "just" for decoration? Will the print be exposed to weather, UV rays, rain? Does the print have to withstand contact with acid? All these aspects will decide which filament will be the right one for you. But to make the right decision, you need to know which filaments are chemically resistant to different chemicals. And that's what we're here for!
What exactly is chemical resistance?
It is the ability of a material to withstand damage and degradation that could be caused due to contact and subsequent action by substances (whether in a solid, liquid or gaseous group). Especially in the industrial sector, there are many substances (such as solvents, alcohol or various acids) that are contained in various cleaning agents, adhesives or paints and varnishes. But even common fuels, motor oil or various perfumes can contain substances that will act on the filament and affect its structure.
How chemical resistance will affect the print
Each filament can be resistant to a different chemical, and another can cause major problems for it. If you do not choose the correct filament, chemicals may affect the print. It then loses its properties, it can become soft, deformed and its functionality generally decreases. Which in the final result can also result in damage to the surrounding components and the entire device in which the specific print is used. The fact that you choose a suitably resistant filament plays a crucial role especially when printing packaging materials, models that are intended for outdoor use, and prints that are part of some device and have a functional character.
You can find filaments on the market that are quite chemically resistant. These include PP, PVDF and nylon. Thanks to this, they can be used to print prints that are subsequently used in the chemical and food industry. PVDF (Polyvinylidene fluoride) filament has found its use in the automotive industry. Mainly because of its extreme resistance. Another filament that ranks among the more durable is PET-G. It is resistant to common chemicals, alcohol and weaker acids. It is often used for the production of packaging materials. On the contrary, a filament such as PLA does not withstand the environment in which chemical substances act.
The degree to which a filament is resistant to a particular chemical depends on several factors. Is part of them:
- type of chemical
- duration of chemical action
- concentration of the chemical
- mechanical stress acting on the material
- print quality
- the temperature at the moment the filament is exposed to chemicals
- the ability to absorb a substance
Filament testing
Finding out how a particular filament reacts with chemicals precedes filament testing. The Spanish company BCN3D, which focuses on the development and production of products related to 3D printing, has tested how an organic solvent (specifically Nitro-P) will affect different types of filaments. It is an aggressive solvent that is often used to dilute paints, so it is possible to come into contact with it on a regular basis. 8 types of filament were selected and partially immersed in the solvent for 24 hours. Then there was a comparison of how much the exposure to the chemical affected the appearance and structure of the prints.
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The aim of the experiment was to simulate accidental contact of a print from a 3D printer with a solvent and then evaluate how much this affected the quality of the print. And last but not least, to point out how important it is to choose a suitable filament that will be chemically resistant. The result of the experiment was that some filaments reacted strongly to the solvent and began to change their structure after a few minutes. These included TPU and PLA, which began to absorb the chemical and swell. Other filaments that were significantly affected by contact with the chemical were ABS and PET-G. The ABS print gradually started to dissolve and the PET-G was damaged on the surface. Conversely, the PP and PP GF30 filaments did not show any change in their appearance even after 24 hours. And they proved to be a suitable filament for printing models in the industrial sector. You can see the detailed procedure and results of the experiment here. |
Chemical resistance of filaments
In the table you will find the chemical resistance of different types of filaments. This is an indicative overview because how the print reacts is influenced by the various factors we wrote about above. With acids, it is important which specific acid it is and in what concentration. For example, nitric acid and cheesy acid in high concentration are very aggressive, and all filaments will have problems with it, except prints made of PP (polypropylene).
1 - very resistant, 2 - moderately resistant, 3 - not resistant
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Chemicals |
PLA | PET-G | ABS | ASA | PC | PP |
| water (H2O) | 1 | 1 | 1 | 1 | 1 | 1 |
| acetone | 3 | 3 | 3 | 3 | 3 | 1 |
| acid | 2-3 | 1 | 2 | 1 | 1 | 1 |
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alkaline chemikals substances |
2 | 1 | 1 | 1 | 1 | 1 |
| alcohol | 3 | 2 | 2 | 1 | 2 | 1 |
| salt | 2 | 1 | 1 | 1 | 1 | 1 |
| UV radiation | 2 | 1 | 2 | 1 | 1 | 1 |
| oil | 2 | 1 | 2 | 2 | 1 | 1 |