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Hybrid Coatings and Sol-Gel Processes with Dynasylan® |
Dynasylan® organofunctional- and alkylsilanes and silicic acid esters are finding increasing use as raw materials for the synthesis of binder systems. They contribute to the high inorganic content of so-called sol-gel or hybrid coatings, improving the following characteristics:
- mar resistance
- UV resistance
- chemical resistance
- thermal stability
- durability
Hybrid coatings may contain at least two of the following components:
- organic resins
- silicic acid esters
- Dynasylan® organofunctional- and alkylsilanes
- AEROSIL® fumed silica, or other metal oxides
That may be combined in many different ways. The silanes are usually co-hydrolyzed with nanoparticles (e.g. fumed silica, silica sol) in a colloidal sol with additional ingredients such as metal oxides.
Organosilanes, most commonly called silanes can make a huge impact on coatings even in small amounts. They are well established as adhesion promoters and surface modifiers but they are increasingly used in many different ways in coatings. Using the chemistry of silanes in your formulation can help you offer new solutions.
The leader in silanes has focused its latest developments on very effective and easy-to-use silanes that respond to the current industry trends such as waterborne and high-solid solutions to formulate coatings emulsions, but also silane solutions fulfilling several functionalities in a single product.
What is a sol-gel process?
In this context, the sol-gel process is a chemical synthesis route in which Dynasylan® organosilanes generally first react in the presence of water and catalysts to form silanols, in a process called hydrolysis. The silanols condense into silane oligomers, which function as network-forming inorganic nanoparticles. The liquid obtained is called a "sol", which can be considered a nano-composite. When the sol is applied to a substrate (metal, glass, plastic, ceramic), the particles condense further, forming a gel, which, depending on reaction conditions, sets as a generally transparent coating with a film thickness of a few μm (also see C. J. Brinker; G.W. Scherer: "Sol-Gel Science", Academic Press, San Diego 1990).
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