Water Repellents

Facades (coated and non-coated) need to be protected against exterior defects i.e. acidic rains, air pollution, microorganism growth, harmful gases, freeze-thaw cycles etc. water, as a vehicle (or as a cause) of many harmful substances is playing a key role in facades damage. So, by protecting from water, a big step is taken to protect the facades. Silicone derivatives are widely used for exterior (and interior) applications to give hydrophobic properties. Silicone hydrophobic agents are used in 2 applications; masonry applications, and coatings.

water repellents

Masonry protection

All masonry materials are hydrophilic and most of them are porous, which let water in and out. Many harmful gases can go in and cause decoloration, corrosion or alkali passivation (in concrete). Salts crystals -which grow in size, along with freeze thaw cycles change the volume inside the masonry materials which result to weaken the construction. In concrete, alkali passivation causes corrosion of reinforcement that increases the volume of reinforcement and consequently damage to concrete.

Silicone impregnating agents are delivered in different forms; solvent thinkable liquids, emulsion, and creamy. They penetrate into the substrate and form silicone networks. They don’t form a film and have no impact on shininess of the substrate. Silicone impregnating agents are durable for decades even when exposed to severe conditions.

In interior applications gypsum based plasterboards are widely used. Gypsum is highly water absorbent. Unlike cementitious substrates, the number of products that waterproof gypsum, is very limited.

Façade coatings protection

Concrete and cement plastered walls are very popular for exterior. Concrete is a porous and highly hydrophilic substance, any coating that are being applied on concrete surfaces should not interfere the breathability of concrete. In other words, the coating itself should be breathable too. On other hand, to reach high breathability of a coating the pigments (and fillers) to resin ratio should increase, which leads to pick-up dirt and absorb more water.

Silicone resins and silicone additives are designed to improve the durability of organic coatings on facades. Silicone resins bring silicone skeleton to the paint which is very stable under UV and weather conditions for a long time without yellowing and degradation.

Silicone additives gives water repellency to the coating which leads to minimum dirt pick-up and air pollution defects.

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