New coating functionalities require new test protocols and devices

New developments arise from the demand for sustainable, more qualitative coatings which combine functionalities. The use of new materials in different sectors and stricter regulations in terms of the use of harmful substances, make it necessary for coating and paint manufacturers to regularly adjust their formulas. In order to correctly evaluate newly developed compositions, it is essential to test them by means of methods which both focus on the coating and on the substrate.  

A few examples of new functional coatings, which have conquered the market in no time, are air-purifying or washable paints, self-cleaning coatings for solar panels and water- and dirt-repellent coatings for mobile phones.

A nice example of how tests evolve together with the new developments is the use of cyclic corrosion tests. Whereas in the past a continuous hot salt spray test was used for solvent-based coatings, a switch to cyclic testing, consisting of a salt spray in combination with UV-exposure, took place due to the emergence of water-based primers and hybrid systems. The reason is that it was found that these cyclic tests correlate better with the actual life span of newly developed coatings.

Growing importance of simulation

More and more test methods are being adapted to not only imitate the functionality in a lab environment, but also to be able to make an accelerated simulation of the durability of the coatings. An example is EN1096-5, a test in which the self-cleaning properties of coated glass are evaluated by repeated cycles of soiling, ageing under UV exposure and cleaning with water spray, in order to simulate the effect of sunlight and rain on the pollution.
 
Antibacterial testing which also focus on the leaching of antibacterial additive, simulation of ice adhesion to test anti-ice coatings on wind turbines or innovative methods to better test anti-fouling-coatings for ships are already widely used. In the future, some of these tests will be converted into standards and will be regarded as standards.
 
Sirris recently performed a test on request of a customer to evaluate the photocatalytic activity of a nanocoating following repeated exposure in a QUV-accelerated ageing chamber. Results show that the photocatalytic effect of the coating decreases only to a limited extent, even after a period of 5,000 hours of QUV ageing (ASTM G154 cycle A).

Sirris monitors the market of new tests for you. Do you have questions about specific tests? Contact the Sirris Smart Coating Lab, we will be pleased to help you out.

(Source picture: M2lab)