PROCESS FOR PREPARING AQUEOUS POLYURETHANE DISPERSIONS

摘要

1. A process for the continuous production of aqueous polyurethane dispersions by mixing of a product, which has been obtained by reaction of polyisocyanates with compounds having a molecular weight in the range from 400 to 10,000 and containing at least two isocyanate-reactive groups, optionally using other starting products and/or additives, with water which may contain additives, characterized in that the mixing of the polyisocyanate reaction product with water takes place in a co-current reactor, one of the components to be mixed or a mixture containing one of the two components to be mixed being compressed to a system pressure in the range from 20 to 500 bar and expanded through a coaxially arranged nozzle 1 into the short-time mixing tube 2 and being mixed with the other component or with a mixture containing the other component.