Process for decreasing the acidic content of polymethylene-poly-phenyl-polyisocyanates mixtures

摘要

The subject of the patented process is the decrease of the acidic content of polymethylene-poly-phenyl-polyisocyanates mixtures by the application of acid sorption material of mineral origin. This acid sorption material is an alkaline mineral with large specific surface area or a synthetically produced inorganic compound, which can be used in the form of powder, granule or other forms of similar nature. The treatment is made by effectively contacting the PMDI and the acid sorption material, and by their subsequent separation. The resulted mixture is proper for the production of polyurethanes.