BTC offers silicate solutions of alkali metals which act as stabilizers for the use in versatile applications. Silicates are also known as water glass or liquid glass. Silicate solutions of alkali metals are known mainly as sodium silicate or potassium silicate. Mainly alkali silicates provide alkalinity beside other properties like adhesion (binding) or stabilisation. The silicate composition and the used alkali metal (sodium, potassium or others) determine the final property of the silicate.
Alkali silicates as stabilizers are often used in
- bleaching formulations;
- detergents & cleaners.
Properties of our stabilizing silicates
Alkali silicates are characterized by their weight ratio of xSiO2:yAlk2O (silica:alkali-metal ratio), which is often documented as molar ratio, or water glass modul. The final BTC silicate products depend on the alkali silicate lumps as base material and the further processing to get the final aqueous silicate solution.
Depending on the used molar weight and water content the silicate solutions are different in viscosity, density and pH-value. Generally all silicates are considered as alkaline (pH >9) solutions. With increasing alkali metal content the pH value increases and the adhesion and binding properties are also enhanced.
Potassium silicates differ in the following properties from sodium silicates:
- they provide less tackiness;
- no-efflorescence occurs;
- they show good solubility;
- they offer high temperature binding properties.
However sodium silicates solutions are economically more attractive if not specific properties like flame colour or no-efflorescence is needed.
Both, aqueous potassium and sodium silicates, are
- purely inorganic (inorganic silica-polymer solution);
- UV-light, thermal and chemical resistant;
- non-toxicological (they show no allergenic or mutagenic potential);
- food-contact approved;
- free of preservatives.
Silicate solutions are sustainable products and thus they are used in many versatile applications.
Portil® is a solid silicate grade produced by a spray drying process. It has an amorphous structure and is easily soluble in case it has to be dissolved again in water.
Applications of our stabilizing silicates
Soluble silicates are reactive raw materials. In almost all applications and uses, liquid silicates are finally converted into a solid silicate which is reversible unless an acidification occurs which leads to a gelling or hardening of irreversible character.
Because silicate solutions contain differently protonated silica-anions (H2SO42-, H3SO4-) a buffer system is provided in an alkaline environment. Such a buffering is a stabilizing effect. It is used in bleaching processes which contain chlorine, or an oxygen-based oxidizing additive. Such processes are used in
- pulp and paper;
- detergents and cleaners;
- hair-bleaching formulations.
Silicate based paints or plaster for mineral surfaces are combined with different other ingredients like polymer dispersion, pigments, wetting agents besides others. The inorganic silicate solution must be stabilized in such a formulation to avoid viscosity increasement or coagulation. The addition of an APEO-free, cationic additive like Cycloquart®, improves the electrolyte tolerance and coagulation is hindered. In addition the in-can viscosity of a finished formulation will remain at a workable level.
Further products used in combination with our silicates
Explore also our
- Complexing agents > for bleach stabilisation in the pulp industry
- Dispersions & additives > for architectural coatings, wood coatings and decorative colours
- Construction chemicals > for ceramic tile adhesives, flooring adhesives, sealants, mortar, building coatings, additives
BTC Europe is BASF's European sales organization for small and medium-sized customers focused on specialty chemicals. Our silicates are used in a variety of industries as
- anorganic binders and additives
- for corrosion inhibition in water systems (pipes)
- for pulp and paper
- as flame retardant
- as binder for coatings for mineral surfaces