Waterborne MDI Emulsion WMD-50

WMD-50 is a self-emulsifying MDI-based polyisocyanate crosslinker designed for aqueous systems. Unlike HDI trimer crosslinkers that require special hydrophilic modification to disperse in water, WMD-50 is pre-emulsified and can be stirred directly into waterborne acrylic or polyurethane dispersions at 5–15% addition level (on total solids). The NCO groups react with hydroxyl groups in the binder (ambient cure at >15°C) as well as with water (forming CO2 and amine, then urea crosslinks). Pot life is 4–8 hours in the mixed formulation. Compared to aziridine crosslinkers, WMD-50 provides better chemical resistance; compared to carbodiimide, it provides better thermal resistance. Key applications: waterborne shoe adhesives, paper-aluminum foil laminates, and wood floor coatings where VOC limits preclude solventborne systems.