Coating compsn. for porous inorganic substrates, e.g. cement - comprising carboxylated acrylic polymer, crosslinking agent and ultraviolet absorber

摘要

Porous inorganic substrates are coated with a protective compsn. which is permeable to gas and vapor and comprises an aqs. soln. or dispersion of a hydrophilic carboxylate acrylic polymer (I) a crosslinking agent for (I) and (pref. 0.1-2 wt.%) a UV absorber, absorbing in the 2700-3300A range. The compsn. pref. also contains polyethyleneimine (II) or a hydrophilic deriv thereof, amt. of (II) and (I) together forming 10-50 wt.% of the soln. or dispersion. Ratio of (II) or its deriv. to (I) is pref. 1-10:1. Amt of crosslinking agent is pref. 1-10 wt.%. Used for protecting eg concrete, marble, cement, plaster etc. from salt water, polluting gases, graffiti and erosion. The compsns. are transparent and impermeable to electrolytes e.g. salt water and acidic rain water.