Silanes, Siloxanes & Silicates
As bridges between organic and inorganic materials, silanes have a broad application spectrum, including as adhesion promoters.
Silanes are the starting point and chief building blocks of silicone production. Pioneering European silicone production, WACKER started to manufacture silanes in 1950. They are produced in WACKER’s integrated production system via direct synthesis from silicon and methyl chloride (Müller-Rochow synthesis). Silicates are then made from tetrafunctional silanes.
Special silanes can be used as building blocks in chemical and pharmaceutical syntheses. WACKER offers a large variety of organofunctional and non-functional silanes.
Organofunctional silanes are hybrid compounds that combine the functionality of a reactive organic group with the inorganic functionality of an alkyl silicate in a single molecule. As a result, organofunctional silanes can be used as molecular bridges between organic and inorganic materials. This bridging property of organofunctional silanes is crucial in many fields of application and in a wide range of industries. Organofunctional silanes are colorless, clear, mobile liquids that are soluble in organic solvents, including anhydrous alcohol in certain cases.
- Adhesion promoter and coupling agent for better anchorage of coatings, adhesives and sealants to many different substrates
- Surface modifier to optimize compatibility and permit the chemical bonding of inorganic fillers to organic polymers
- Curing agent for organic polymers, e.g., in moisture-curing adhesives and sealants or paints and coatings.
- Water scavenger in moisture-curing polymers
- Crosslinker for polyethylene, for manufacturing heat-resistant pipes or insulating cable sheathing
- Hydrophobic agents for the protection of construction materials
- Silylating agents
- Construction material
WACKER’s portfolio includes a variety of product formulations based on silanes, allowing application-specific solutions. Mixtures of silanes and siloxanes are used to create the desired balance between penetration characteristics and surface effects.
- Hydrophobic agents for the protection of masonry and construction materials
- Protection of infrastructure against the ingress of harmful salts
- Protection of concrete against destructive chemical processes
- Admix applications in dry mixes and concrete
- Damp-proofing against rising damp
- Construction chemicals
- Construction materials
The creamy consistency of silanes allows them to be easily applied onto vertical surfaces in measurable quantities and results in an increased contact time between the silane and surface. This ensures better penetration characteristics and ultimately improved performance.
Silane-based emulsions can be diluted with water or easily incorporated into water-based formulations without high shear mixing.
In addition, silane-based powders are ideal for achieving tailor-made hydrophobicity in dry-mix applications.
Silicates are derived from oligo-silicic acids and differ from silicones by their content of residual alcohol groups. Further curing takes place by the addition of catalysts, such as sulfuric acid. Silicates include all salts and esters of silicic acid.
Organic silicates, such as esters of monosilicic and disilicic acids, can only be produced synthetically. Inorganic silicates, with the exception of alkali silicates (waterglass), are an important group of naturally occurring silicon-oxygen compounds (silicate materials).
- Stone conservation
- Binders for zinc-rich coatings
Potassium methyl siliconate is a highly alkaline aqueous solution. Diluted with water, it is used for the in-plant water-repellent impregnation of heavy clay products, such as roof tiles, floor tiles and flower pots. After the water has evaporated, the potassium methyl siliconate reacts with atmospheric carbon dioxide (CO2) to form K2CO3 and the water-repellent active agent poly(methyl silicic acid).
- Hydrophobic agents for clay-based materials, such as bricks and roof tiles
- Surface treatment of gypsum-fiber boards
- Impregnation of insulation materials (perlite, expanded clay, etc.)
- pH adjustment in water-based coatings
- pH control in the production of polymer dispersions
- Construction materials
1,1,1,3,3,3-Hexamethyldisilazane is available as a colorless liquid with a purity of min. 97.0%, min. 98.0% or min. 99.0%. It can be used as a universal silylating agent, for example, for the derivatization of alcohols, carboxylic acids, amines and amides.
- Universal silylating agent, e.g. for the derivatization of alcohols, carboxylic acids, amines and amides