Bayhydrol XP 2558 Polyurethane Bayer MaterialScience Polyurethane (PU) - Polyurethane dispersions (PUDs) Coatings >> Waterborne water Bayhydrol XP 2558 is a cosolvent free aliphatic, anionic polyurethane dispersion. It is used as a binder in the formulation of water-reducible coatings and sealers. The product is characterized by high resistance to yellowing, very good wet film transparency and very good abrasion resistance (taber). Films are hard but flexible. Post-curing of such coatings with Bayhydur®, for example, brings additional advantages and results in waterborne two-component coatings with significantly higher mechanical and chemical resistance. The mixing ratio of mill base to hardener is generally 10:1. Compatibility with affordable PAC dispersions is good but must be tested on a case-bycase basis.. As with any product, use of Bayhydrol XP 2558 in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability. Aliphatic, anionic polyurethane dispersion. Offers high resistance to yellowing. Provides very good wet film transparency and very good abrasion resistance. Possesses higher mechanical and chemical resistance.