METHOD FOR PROTECTING CONCRETE BUILDING STRUCTURES FROM CORROSIVE EFFECTS OF UREA Russian patent published in 2023 - IPC C04B41/62 

FIELD: protecting concrete building structures.

SUBSTANCE: method for protecting concrete building structures from the corrosive effects of urea includes the sequential application of two impregnating compositions to the concrete surface, the first of which is a composition containing urea-formaldehyde pre-condensate - a 75-80 wt.% aqueous solution of methylol urea and formaldehyde with a molar ratio of urea:formaldehyde equal to 1:(2.7-3.3) and acid agent, taken at the following ratio, wt.%: urea-formaldehyde precondensate 99-99.99; acid agent 0.01-1. The second impregnating composition is applied as the second layer: an aqueous solution containing 35-42 wt.% urea and 3-10 wt.% vinyl acetate dispersion.

EFFECT: increase in the service life of the applied anti-corrosion coatings, as well as elimination of highly toxic formaldehyde emissions into the atmosphere when applying a protective composition.

1 cl, 3 ex