Polycarbodiimide and polyurethane cross-linkers for leather finishing

This review focuses on polyurethane and carboxylic acid-carbodiimide cross-linked systems for leather fi nishes. Recently, these cross-links have become very popular in leather finishing. The cross-links in leather finishes improve the strength properties of the finished leather, the excess of cross-links causes brittleness. The multifunctional carbodiimide cross-linkers are useful for leather surface properties improvement. The carbodiimide groups are sensitive to hydrolysis; life time of this functional group during polymerization is enhanced. Water dispersible isocyanates, polyurethane copolymers and polyisocyanate cross-links have applications in new technologies are discussed in this review.