Adhesion on mineral and metal substrates can be difficult with common adhesive and finishing materials. For example epoxy, isocyanides or acrylic adhesives or coatings that can be used on natural stone or metal surfaces.
To improve the compatibility between these substrates and the formulations based on organic chemistries, Silane adhesion promoters can be used. These are organosilicon molecules, in which the Silane groups can react with the substrate. After which the organic part is available as anchor points for covalent bindings on these difficult surfaces.
Methoxy- or Ethoxy-silane groups are hydrolyzed to an organic alcohol and a very stable silicium – oxygen – substrate bond. These components can be applied as a wash primer, or be mixed in the adhesive or coating formula to improve the adhesion.
Variation in the Silane side can be done by picking ethoxy or methoxy groups. In general, methoxy groups have a faster reaction speed. Ethoxy-types are less fast, increasing the workable time. Also the by-product of ethoxy types is the relatively safe ethanol.
On the organic parts the choice is very large. Most often an epoxy or amino functionality is chosen, because these technologies already have very strong adhesion properties. Another option is to choose a vinyl- or methacrylate group to combine with radical cured coatings like UV-coatings or alkyds.
Next to substrate adhesion it is also possible to crosslink mineral fillers, fibers and pigments in rubber and composites. By integrating the mineral fillers and fibers into the organic molecule phase, improvements of mechanical properties and chemical resistance can be achieved.
In certain types of coating applications it is also possible to use Silanes as cross-linker, where a hydroxyl functionality is used as anchoring point for the Silane reaction.
Whatever your application or technology might be, we are happy to help you pick the correct Silane for your formulation. Samples are available to determine the added value in your system.