Mixture of ethyl esters of different polysilicic acids for the consolidation of construction material
Protectosil SH is a mixture of ethyl esters of different polysilicic acids for the consolidation of construction material.
Protectosil SH is immiscible with water, so hydrolysis therefore requires a co-solvent such as ethanol, methanol or white spirit. Mineral acids, ammonia, titanates or tin compounds are suitable as catalysts.
Protectosil SH is a colorless, low-viscosity liquid with an SiO2 content of 40 %. The polysilicic acids still have a sufficient content of ethoxy groups, which can be activated by acid- or base-catalyzed hydrolysis. Condensation starts even during hydrolysis, with the formation of relatively large polymeric molecules. During storage of these hydrolysates, condensation continues until a gel is formed, the gelation rate depends on the degree of hydrolysis.
The action of the hydrolysates as binders is based on the continuation of the hydrolysis with subsequent gelation and dehydration to give polymeric SiO2 structures.
Protectosil SH is used to deposit silicic acid formed as a result of complete hydrolysis. The resulting silicic acid bonds well to many mineral, inorganic substrates, such as natural stone, brick or terracotta stones. The deposition of a thin SiO2 layer improves the chemical and thermal stability and mechanical properties. In the case of porous mineral substrates Protectosil SH is used for stone consolidation. Depending on the kind of natural stone Protectosil SH is used in specifically developed formulations as a silica source.