Manchester, UK (April 2012) – Elcometer are pleased to announce the launch of their new Amine Blush Test Kits which have been designed solely for use in the quick and immediate qualitative identification of amine blush (carbamates) on the surface of coatings.
The Elcometer 139 Amine Test Kits are available in two versions; a swab test – ideal for on-site analysis and a chip screen test – allowing physical coating chips or shaving samples to be sent
either to a third party or to a laboratory for further analysis.
Whilst existing test methods rely on detecting changes in pH values on the surface and associating this with the presence of amine blush, it has been shown that this test principle is flawed - giving both false positives and false negatives as pollutants such as acid rain affect pH values of the surface.
“The Elcometer 139 Amine Test Method uses a chemical test to specifically test for amine blush (carbamates) and therefore does not give rise to false responses” stated John Fletcher, Elcometer’s Technical Support Manager. “A test method which gives false positives or negatives can cause significant unnecessary cost in the re-coating process. Following extensive field trials, the Elcometer 139 Amine Blush Test Kits have been shown to be entirely reliable. You can even use a colorimeter to assess the level of concentration.”
About Amine Blush
When using amine cured epoxy resin coatings in a multi-layer system, if the original coating cures in a low ambient temperature and / or in a high humidity environment, problems - referred to in the industry as amine blush - can develop.
Amines that have migrated to the coating surface can react with the carbon dioxide (CO2) present in the air, ultimately resulting in the formation of carbamates (amine blush) on the surface of the coating. In some instances, this can be observed as an oily film on the surface but is often invisible to the eye.
The presence of amine blush (carbamates) will cause inter-coat adhesion failures if a further coat is applied without prior removal of amine blush. It is therefore essential to establish if the coating exhibits the phenomenon of amine blush when determining if an amine cured epoxy coating can be over coated.
For more information on the Elcometer 139 Amine Blush Test Method or amine blush, please contact Elcometer.