Patent ID: 7439316
Filing Date: 2008-10-21
Classification: C08G

Abstract:
1. A process for the preparation of stable aqueous polycarbodiimide dispersions, to be used as crosslinking agent, which are free of organic solvents, the process comprising the steps of: reacting a polyisocyanate in the presence of a carbodiimide catalyst to form a stable polycarbodiimide; terminating and/or chain extending the polycarbodiimide chain by the addition of a compound containing a hydrophilic group and one or more amine and/or hydroxyl functions during or after the polycarbodiimide formation; and dispersing the resulting compound in water, wherein the pH is adjusted to a value between 9 and 14 by the addition of a base and/or a buffer to the water used for the dispersion and/or to the obtained aqueous dispersion; and wherein said terminating or chain extending with the compound containing a hydrophilic group and one or more amine functions occurs during or after the dispersion of the polycarbodiimide in water.