Silanes and Siliconates
Dow pioneered the development of silanes – and the synergy of organic and silicon chemistries – more than 60 years ago. Today, they remain instrumental in allowing new materials to be developed in a wide variety of industries with greater reliability and improved performance. And Dow continues to be a leader in developing and supplying silane solutions.
A silane is a molecule comprised of one central silicon atom with four attachments. These substituent groups can be nearly any combination of nonreactive, inorganically reactive, or organically reactive groups. Silanes are the smallest silicon-based molecules, ensuring good depth of penetration into substrates. A silane that contains at least one carbon-silicon bond structure is known as an organosilane. In many applications, the term “silane” is a generic term typically referring to an organofunctional alkoxysilane. Here, the terms silane, alkoxysilane and organofunctional alkoxysilane are used interchangeably. They react with themselves and any hydroxyl (OH) groups within the substrate, often when moisture is present, forming a silicone resin network. This formation of strong chemical bonds provides durability.
Functions and Benefits
- Coupling Agent
- Adhesion Promoter
- Hydrophobing and Dispersing Agent
- Moisture Scavenger
- Silicate Stabilizer
Water Repellents and Surface Protection
Nature can be a tough adversary – water intrusion, sunlight, wind and abrasion, infiltration of organisms, or even accidental stain damage. Silanes can give water- and stain-repellent properties to surfaces. Alkoxysilyl groups attached to these silanes allow them to penetrate, cure in and bond to many inorganic substrates. These unique properties allow for versatile and durable solutions to protect against harmful water- and oil-borne elements.
Paints, Inks, and Coatings
The unique capabilities of silanes make them ideal for high-performance paints and coatings, as do their ability to withstand physical, chemical, environmental and thermal degradation. They can be used in waterborne or solventborne formulations, are compatible with most binder systems, are suitable for low-VOC, sustainably formulated products and are versatile and easy to use.
The use of silanes in coatings can provide improvements in adhesion; resistance to moisture, chemicals, ultraviolet (UV) rays and abrasion; and improved dispersion of fillers. Silanes are also used as intermediates to produce silicates and siliconates via reaction with metal hydroxide. These materials are used in protective finishes, such as zinc-rich primers, masonry treatments for water repellency, or compounded directly into concrete coatings for improved physical properties and water repellency.