Technology 2023

Reality Or Visions?

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Reality Or Visions?
Reality Or Visions?

Video: Reality Or Visions?

Video: Reality Or Visions?
Video: Shirley visions of reality 2013 2023, April
Anonim

Infrared colors, hollow microspheres, nano-hybrid: what do innovative facade coatings really do and what are the limits of new technologies? Franz Xaver Neuer, Caparol Different technologies are being discussed for facade paints in order to prevent major problem areas such as pollution and the growth of fungi and algae in the long term. In the following, we will therefore examine what the innovations actually stand for and what may only be relevant from a marketing perspective. First of all, it should be noted that the mode of action of facade paints is particularly put to the test when revising thermal insulation composite systems (ETICS). Since the thin layer of plaster is thermally almost separate from the actual masonry, the plaster cools down quickly in the cold at night. The plaster heats up quickly in direct sunlight, but heat storage is almost impossible. That is why insulated facades get dirty faster than uninsulated ones. The shell of the house must protect against all influences from inside and outside. Whether water vapor from the inside or rising moisture or salts from the outside: protection functions against everything must be available within the facade system. This also applies to sunlight, heat, frost, rain, dust as well as dirt or chemical and mechanical influences. The technology that can best withstand these influences is the most likely to protect the facade from soiling, fungal or algae growth and weathering. Soiling of facades Facade pollution depends on the structure and chemistry of the surface,the building physics influences as well as the boundary conditions for algae and fungal infestation. If a facade is rough and highly thermoplastic and tends to condense, it will always get dirty more easily than other surfaces. It is therefore important to rule out these adverse factors as much as possible. Extreme hydrophobicity (moisture-repellent effect) tries to prevent moisture from reaching the surface. Practical examples and many test series have shown, however, that this alone is not enough to prevent pollution. This is particularly evident on busy roads with high levels of particulate matter. A possible reason is that the water drops do not “run off” completely, but remain partly on the surface. As a result, fine dust collects on the water surface, which remains on the facade after drying. One solution is to use capillary hydrophobia. When it rains, a thin film of water forms on the surface, so that the ingress of moisture due to the hydrophobized capillary is effectively prevented. The wafer-thin water film enables the surface to dry very quickly and little fine dust can be deposited on it. In addition to capillary hydrophobicity, thermally and hygrically stable binders are required to prevent dirt particles from sticking together. Other parameters to effectively prevent contamination are a finely structured surface that offers as little contact area for dirt as possible, a photocatalytic effect through titanium dioxide,to repel deposited dirt and not to provide a breeding ground for fungi and algae. Temperature increase In order to avoid condensation on the plaster surface, in addition to hydrophobicity, the focus is on falling below the dew point. To do this, the temperature of the facade would have to be kept above the dew point at night. If this were successful, the risk of fouling with algae and fungi would be significantly reduced, especially on insulated facades. The following approaches are considered, among others:the risk of fouling with algae and fungi would be significantly reduced, especially on insulated facades. The following approaches are considered, among others:the risk of fouling with algae and fungi would be significantly reduced, especially on insulated facades. The following approaches are taken into account:

  • IR reflection Infrared (IR) -active colors are supposed to reduce the heat emitted at night by special pigments in the top layer of plaster in order to keep the surface temperature above the dew point. If this is possible until the wee hours of the morning, condensation could be prevented and the risk of fouling reduced. Especially in spring and autumn with warm days and cold nights, it can be seen that the drop below the dew point is reduced and less. However, since the dew point falls below the dew point in the early morning hours, condensation is usually given. This cannot be definitely prevented by IR-active colors.
  • Hollow microbeads as functional fillers In some facade colors, light fillers in the form of hollow spheres made of ceramic, glass or plastic are used. These either create a vacuum, a vacuum or are filled with inert gas. In addition to reducing the weight of the paint, the thermal conductivity is also greatly reduced. In this way, the stored heat should be kept in the paint longer and the plaster layer should not cool down as quickly. Here, too, the condensation on the plaster surface should be prevented as long as possible to prevent infestation with fungus and algae. However, it is easy to imagine that in a paint with dry layer thicknesses of 100 to 150 micrometers, there is only a very low efficiency of this effect.
  • Latent heat accumulators: Phase Changing Materials (PCM) Latent heat accumulators are functional fillers that should be able to store energy (heat) during the day and to release them again after cooling down at night. These are plastic-coated wax balls with an individually adjustable melting and solidification point between zero and thirty degrees Celsius. During the day, the wax beads melt due to the absorption of heat and keep the temperature constant during the melting process. Therefore, there is a cooling process even in this phase. When cooling down at night, this temperature remains constant until the solidification process is completed. The thin layers of paint cool down too quickly. A noticeable effect can only be noticed in higher layer thicknesses through larger quantities of wax beads. The condensation takes place to almost the same extent, so protection against fungi and algae must be guaranteed differently. Use indoors is more conceivable, for example in the form of gypsum plaster or plasterboard.
  • Nano-silver as an alternative for biocidal agents? With regard to the question of whether nano-silver can replace biocides, the first thing to note is that nano-silver has an antibacterial effect. The effectiveness against fungi and algae is only slight and only available through the addition of larger amounts. To prevent a gray cast in the color, only small amounts of nano-silver may be added. Use indoors is more conceivable than on the facade. There are already products that have proven themselves here.

New types of binders New binders also expand the properties and benefits of facade paints. This has been achieved with a silanized pure acrylic by combining the mineral properties of a silicone resin facade paint with the variety of colors of a pure acrylic facade paint. In order to keep up with the application spectrum of silicone resin facade paints, dispersion silicate facade paints were combined with silica sols. This also guarantees adhesion to old organic coatings. These so-called sol-gel silicate paints expand the spectrum of silicate paints and their application. The latest innovation in the binder sector for facade paints is the so-called nano-hybrid. They represent a further improvement in the materials in order to protect facades from contamination for an even longer time. With these new binders, not only facade colors are feasible, but also other materials such as colored stone and pasty plasters. Conclusion Most of the technologies explained are not yet mature today. However, visions are allowed which - like IR-active colors - could play a role in the future. Technologies that target hollow microspheres or latent heat storage are more suitable for indoor use. The new Nano-Hybrid binder for facade paints is an already significant innovation. Its possibilities are far from being exhausted. Fungicides and algicides in facade colors remain indispensable for “critical” objects. Conclusion Most of the technologies explained are not yet mature today. However, visions are allowed which - like IR-active colors - could play a role in the future. Technologies that target hollow microspheres or latent heat storage are more suitable for indoor use. The new Nano-Hybrid binder for facade paints is an already significant innovation. Its possibilities are far from being exhausted. Fungicides and algicides in facade colors remain indispensable for “critical” objects. Conclusion Most of the technologies explained are not yet mature today. However, visions are allowed which - like IR-active colors - could play a role in the future. Technologies that target hollow microspheres or latent heat storage are more suitable for indoor use. The new Nano-Hybrid binder for facade paints is an already significant innovation. Its possibilities are far from being exhausted. Fungicides and algicides in facade colors remain indispensable for “critical” objects. The new Nano-Hybrid binder for facade paints is an already significant innovation. Its possibilities are far from being exhausted. Fungicides and algicides in facade colors remain indispensable for “critical” objects. The new Nano-Hybrid binder for facade paints is an already significant innovation. Its possibilities are far from being exhausted. Fungicides and algicides in facade colors remain indispensable for “critical” objects.

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Some of the technologies described are already implemented in facade colors today. The “Caparol Clean Concept” (CCC), for example, uses capillary hydrophobicity to enable the facade surface to dry quickly. In addition, thermally and hygrically stable binders are used in the CCC products, which prevent dirt particles from sticking together. Other parameters of the CCC are a finely structured surface that offers as little contact area for dirt as possible, a photocatalytic effect due to titanium dioxide to repel the dirt and therefore not provide a breeding ground for algae and fungi. For more information on the Caparol Clean Concept, contact Caparol Tel.: (06154) 71-0 / Fax: -1391 www.caparol.de

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