In the RFQs for surface protection for the chemical industry, there is a specific demand for the application of a functional coating called Halar, under which the fluoroplastic ECTFE manufactured by Solvay is hidden. This requirement is mainly due to the general knowledge of Halar ECTFE in the chemical industry as a corrosion resistant coating.
There is, however, another variant of surface treatment with comparable properties to Halar ECTFE. This alternative is the application of ETFE in both variants: ETFE Ultra + and ChemResist rotational lining. In our paper we compare both types of surface treatment and explain their differences.
If you are interested in other ways to protect the surfaces, check out our complete surface treatment portfolio.
Although both types of surface treatments have the same maximum working temperature (150 °C), there are differences in limit values. The melting point of Halar ECTFE is 240 °C and the melting point of the ETFE coating is 260 °C. ETFE has lower low-temperature brittleness than Halar ECTFE. Thus, standard temperature resistance is the same, ETFE is safer at higher temperature fluctuations.
The chemical resistance of both types of coatings is also closely related to the temperature and concentration of the medium with which the coating is in contact. ETFE resists a wider range of chemicals at higher working temperatures than Halar ECTFE. If we compare different types of chemicals and their particular effects on individual coatings, ETFE only fails when exposed to strong acids or bases at very high temperatures. Halar ECTFE loses its chemical resistance when in contact with acids, bases and halogens at high temperatures. Furthermore, amines, esters, ketones and solvents are a problem for the Halar ECTFE.
|Bases||Suitable||Cracks may appear|
|Organic solvents||Suitable||Blisters may appear|
The comparison of the two coatings is based on laboratory tests (we provide the test results table to our customers for their assessment). However, it is always advisable to test the selected coating directly at the factory, since all variables cannot be captured by laboratory testing. For this purpose, we provide our customers with sufficient amount of samples.
Another factor that plays a role in protecting the surface against aggressive chemicals is the method of applying a layer of the selected coating and its sufficient thickness. Only if the applied layer is non-porous throughout its whole surface it can provide the highest protection. Rudolf Gutbrod GmbH, with over 50 years of experience in surface protection not only for the chemical and pharmaceutical industries, is able to apply this high-quality coating. In addition, after each application, the entire coated surface is checked by a porosity test to detect any quality issues. BALTRO as a representative of Rudolf Gutbrod GmbH for CZ, SK, PL and Baltic States is able to provide its customers with this service and help to find a surface protection solution.
Both types of coatings have similar electrical properties. In terms of mechanical properties, ETFE has a smoother surface and is more resistant to cracking.
In addition, ETFE fluoroplastic can be applied to the inner surfaces of a variety of components using unique technology ChemResist, about which you can read in a separate article.
ETFE is usually also a cheaper solution. In addition, there is a shortage of Halar ECTFE on the world market in 2019 and 2020.
By comparing ETFE and Halar ECTFE with standardized tests, ETFE is considered to be generally better and safer surface protection option for the chemical industry. Despite the mentioned advantages of ETFE solutions, we often find that customers have to insist on Halar (eg. due to the technical documentation they cannot change). Therefore, we can offer coating with both ETFE and Halar ECTFE.