Method of protecting a surface
AssigneeEka Chemicals AB
InventorsMarek Tokarz, Michael Persson, Roman Kozlowski
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Abstract
A method of protecting a porous material sensitive to corrosion caused by pollutants in the atmosphere. The method comprises treating the surface of the material with an agent containing more than 90% by weight of silica sol. The agent contains substantially no solid particles with a diameter exceeding about 1 micron. Porous building materials comprising a layer of gelled silica sol present in the pores below the material surface are prepared by the method.
Claims23
A method for protecting a porous material sensitive to corrosion caused by pollutants present in the atmosphere, comprising treating the surface of the material with an agent, said agent containing (i) substantially no solid particles with a diameter exceeding about 1 micron and (ii) more than 90% by weight of silica sol having an alkali metal content in the sol, expressed as Na.sub.2 O, of less than 0.1% by weight, said silica sol being either anionic, alkaline and stabilized with volatile cations or acidic and stabilized with H.sup.+ ions, to form a layer of gelled silica sol within the pores below the surface of the porous material.
A porous building material comprising a layer of gelled silica sol present in the pores below the material surface substantially uniformly distributed within the pores from the surface to a depth of at least about 2 mm, said silica sol containing less than 0.1% by weight of alkali metal, expressed as Na.sub.2 O and said gelled silica sol containing substantially no particles with a diameter exceeding about 1 micron.
Dependencies are inferred from the claim text.