Concrete preparation with aqueous solution of product from polyether with polymethylene polyphenyl polyisocyanate

摘要

The structural strength properties of concrete and its resistance to sealing are improved by incorporating into the concrete-forming mixture an aqueous solution obtained by admixing polymethylene polyphenyl polyisocyanates with less than a stoichiometric amount of a polyethylene glycol (MW 600 to 3000) or polypropylene glycol tipped with 15 to 85 percent ethylene oxide (MW 1000 to 3500) and, within a short time of completing the admixture but during the period where said mixture is completely soluble in water, dissolving said mixture in water. Optionally, a difunctional extender is added to the solution so obtained in an amount less than that required to react with all the excess isocyanate groups.