Evonik Degussa Silanes - Frequently Asked Questions (FAQ's)
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1 Can a surface treated with silane-based water repellents be painted?
Yes and no - the answer depends both on the type of water-repellent and paint formulation used. more...
 
2 How can I remove graffiti from a surface treated with Protectosil ANTIGRAFFITI®?
A surface treated with Protectosil ANTIGRAFFITI® may be easily cleaned with most commercial graffiti removers (follow manufacturers instructions) and a pressure washer. The protective coating remains undamaged even after repeated cleaning cycles.
 
3 How can we improve adhesion to concrete?
Due to its porous structure and the basic surface pH, concrete is a difficult-to-bond substrate. Depending on the resin system silane/silicic ester primers may be required.
 
4 How do I apply Protectosil ANTIGRAFFITI® so that the graffiti protection is permanent?
Depending on the type of substrate, several (usually three) applications of undiluted Protectosil ANTIGRAFFITI® are required to achieve permanent protection. The surface must be allowed to dry completely between applications, this is dependent upon weather conditions but in general 30 - 120 minutes drying time is sufficient. More information is contained in the Technical Information on applying Protectosil ANTIGRAFFITI® (download from Literature page).
 
5 How do we apply the silane to the filler?
Typically the neat silane is sprayed on an agitated filler in a mixer. Temperature, surface moisture, by-products, and dwell times need to be monitored carefully.
 
6 How do we prepare an existing masonry surface for treatment with Protectosil® water repellents?
For normal dirt and grime, pressure-washing with or without a light-duty cleaning agent is typically sufficient. Mold or fungus should be removed with a sodium hypochlorite solution in addition to pressure-washing. Efflorescence and mineral deposits should be removed with a chemical cleaner specifically designed for that purpose, following the application instructions carefully, especially for neutralization and rinsing of the substrate.
 
7 How long must we wait to treat new masonry?
It is recommended that new concrete and masonry be allowed to cure a full 28 days before applying silane-based water repellents.
 
8 How much silane is needed to achieve uniform filler surface coverage?
Usually 1wt.% based on the filler is used for fillers with a surface area of less than 20 m2/g. Higher surface area fillers require a higher silane dosage.
 
9 How much silane should we use to improve adhesion?
Typically 1wt.% based on the formulation is a good initial starting point. However, you need to optimize that through further testing.
 
10 How will contact with water harm the effectiveness of silane-based water repellents?
Alkylslkoxysilanes are water-reactive molecules. This chemical reaction with water, known as hydrolysis, causes the silane-based water repellent to chemically bond with the substrate it is applied to. more...
 

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