Importance

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Abstract

The present invention is directed to a process for sealing and/or priming concrete by applying to concrete an aqueous polyisocyanate dispersion which has an isocyanate content of at least 0.5% by weight, based on the weight of the polyisocyanate, and is prepared by a) dispersing in water a polyisocyanate which has an isocyanate content of at least 12% by weight and b) optionally reacting the dispersed polyisocyanate with i) a primary or secondary monoamine containing at least one hydroxyl group in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0:1.0 to 0.7:1.0 and/or ii) a polyamine having primary and/or secondary amino groups and a molecular weight of 400 or less in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0:1.0 to 0.4:1.0, provided that when components i) and ii) are both reacted with the dispersed polyisocyanate, component i) is mixed with the dispersed polyisocyanate either before or during the mixing of component ii) and the equivalent ratio of amino groups from both components i) and ii) does not exceed 0.95:1.0. The present invention is also directed to the primed and sealed concrete obtained in accordance with this process.

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First Claim