Polycarbodiimide crosslinkers

Polycarbodiimides are very efficient crosslinking agents for carboxylic group containing polymers in water, such as polyurethanes, polyacrylates and latexes. They are an environment friendly replacement for the former frequently used polyaziridines and in particular they are non-mutagenic. A great step forward in the development of crosslinkers are the polycarbodiimides containing additional functional groups which contribute to the crosslinking. At applying the polymers in water together with these polycarbodiimides an additional inter-polymer network is formed by the additional functional groups. As a result the film properties, such as the film strength, water and chemical resistance, abrasion properties, of the obtained film are enhanced.The latest developments are solvent-free polycarbodiimide dispersions in water, which are of particular interest when solvent free systems are required.