NQG³- Dry Facades Thanks To Nano Quartz Grid Technology

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-11-26 11:39

Nano-quartz grid technology (NQG) has been used for facade paints by Caparol for more than eight years. The company's researchers have now decisively developed the technology further. As NQG³ technology (read: NQG to the power of three), it has a number of improvements

NQG products have always combined the advantages of silicone resin and silicate paints, on the one hand chalk stability and flexibility, on the other hand surface hardness and durability. The three-dimensional nano-quartz lattice leads to a hardness that almost completely excludes the thermoplasticity of the binder, even at high summer temperatures. This significantly reduces the tendency to become contaminated, i.e. the adherence of dirt particles, fine dust and spores. Anything that sticks to the façade at short notice will be released when the next wind and rain come in. Swelling of the binder is avoided, protective function and color brilliance are retained.

A new measuring method made it possible to precisely observe, analyze and record the drying behavior of coated surfaces. By evaluating the measured values and various test series, the next stage in the development of nano-quartz lattice technology could be reached. NQG³ has been proven to offer the fastest drying time thanks to intelligent moisture management. Any moisture that occurs is absorbed by NQG³ and distributed over a large area in the top layer. The largest possible surface and shallow penetration guarantee the fastest possible drying. The very short idle times in which the NQG³ products are moist reduce the risk of algae and fungal attack.

The NQG³ technology

With the nano-quartz-lattice technology, nanoscale silicate particles are firmly and inseparably connected to the remaining binder particles during the production of the organic binder. This results in a stable binder structure with inorganic pigments, which ensures longer color stability. Now the new NQG generation is there with an improved formulation and even faster drying. The drying time of the facade is a decisive factor, especially for minimizing algae and fungal attack.

The “capillary-hydroactive” drying management of the NQG³ color works as follows: moisture is distributed on the surface and is largely kept away from the facade (figure on the left). At the same time, water vapor can escape and the moisture evaporates on the surface (figure on the right). The surface structure of NQG facade paints enables a more even distribution of weather-related moisture. This effect leads to faster evaporation, since moisture cannot accumulate. Capillary hydrophobicity ensures that moisture is largely kept away from plaster and masonry and the conditions for microbial infestation are significantly worsened.

During the development of the NQG³ technology, comparative tests were carried out against high-quality facade paints (without nano-quartz grids) that are customary on the market. Because the declared claim is to prove the product promise "even faster drying". This aspect is particularly important to avoid algae and fungal attack. In order to substantiate the effect, laboratory tests were first developed with specially developed measuring systems in which NQG³ showed up to 30% faster drying after intensive watering than the comparison colors.

This was measured and visualized spectroscopically using a special infrared camera. The darker the color, the more moisture there is on the surface. In the next step on larger, plastered test panels, the difference was clearly visible even without measuring devices. An official order measurement is currently being carried out by the Fraunhofer LBF (Laboratory for Durability) for the project. The declared goal is certification in the form of a scientific study.

NQG³ in the test

So far, it has been difficult to examine the drying process of facade coatings and to optimize them under realistic conditions. In order to be able to see water with the naked eye at all, a supposedly quick drying was sometimes demonstrated on smooth, non-absorbent surfaces and with splash water. However, tests have nothing in common with the real scenarios in which condensation and driving rain put an equal load on the coating. In addition, a fine structuring of the surface changes the drying behavior fundamentally, since the water settles almost invisibly between the grains.

NIR measurement method

A measurement process developed at Caparol now enables customers and developers to view drying on real substrates and under various conditions for the first time. The process uses the characteristic signature of water in the near infrared (NIR), as is also used in astrophysics to explore water in space: While water is transparent to our eyes, occurs in the near infrared (NIR) at a wavelength of 1450 nanometers of strong absorption - you could say that water is colored here.

With a NIR camera specially modified for Caparol, this water signature can be measured and displayed live. Water deposits between the grain and even capillary-bound water are clearly visible. Another advantage is the penetration depth of the measuring process of typically up to 70 micrometers. This is particularly important because it is precisely in this layer close to the surface that water is still available for the growth of algae and fungi, although the surface already suggests a dry surface for the human eye.

The trial farming

The absorption caused by water initially results in an image in grayscale, which can be displayed in high contrast in the false color representation familiar from thermography cameras with a color gradient from violet to light yellow. Dry areas are shown in yellow tones, water drops in purple (see pictures).

The performance of the new generation of NQG³ facade coatings is shown here using the comparative drying of Thermosan NQG³ as a high-quality hydrophobic facade paint. The condensation outweighs the driving rain over the duration of the exposure. The long-term falling below the dew point places special demands on facade coatings.

Under the conditions of natural condensation, samples of a complete ETICS structure were initially moistened slowly. The drying (redrying) was then measured. The dew initially forms fine drops on the surface of both coatings, which grow and settle in the structure of the surface. Even during condensation, the NQG³ technology leads to a more even distribution of the water on the surface. As soon as no more moisture is added, the remaining drops spread and the resulting large surface ensures that the coating dries quickly and evenly. After 16 minutes, there are therefore no water drops on the surface in this test. Another picture is shown with the hydrophobic coating:The beading effect prevents the water from being distributed on the surface and causes it to contract into large drops. However, the fine structure of the surface prevents the drops from running off. The consequence: after 44 minutes, the last drops of water have disappeared from the surface.

Over the lifespan of a facade, the longer service life of water shown increases the risk of algae and fungi. Once again, Caparol's research helps the craft make decisive technical progress with innovative ideas. We are now able to visualize and contain the main cause of the algae and fungal infestation.

These are the advantages

Clean longer: Small, hard quartz particles prevent dirt from sticking to the surface.

The proven NQG technology is based on a hard surface with a mineral character that does not tend to thermoplasticity and remains hard even in extreme sunlight. This significantly reduces contamination by sticking dirt particles, fine dust and spores. Anything that remains on the facades for a short time will be washed off when the next rain hits. Swelling of the binder is avoided, protective function and color brilliance are retained.

Faster dry: Moisture is distributed on the surface and evaporates quickly. This deprives algae and fungi of their livelihood.

Moisture is transported outside even faster - with NQG³, facades dry measurably faster. This has been scientifically proven with specially developed measurement and test methods in multi-stage comparative tests. You can read detailed information about the drying tests in the NQG³ section of the experiment.

Beautiful for longer: A stable binder structure with extremely lightfast inorganic pigments creates long-term color stability.

With the nano-quartz-lattice technology, nanoscale silicate particles bond inseparably with the remaining binder particles during the production of the organic binder. The color-stable inorganic pigments are firmly integrated in the grid. The advantages are minimal chalking, long color stability and high color brilliance.