Waterborne polyurethanes are mostly milky white.

The whole process of waterborne polyurethane can be divided into two stages. The first stage is pre-stepwise polymerization, that is, the oligomeric diol, the chain extender, the water-based monomer and the diisocyanate are progressively polymerized through the solution to produce an aqueous polyurethane prepolymer having a molecular mass of the order of 1000. The second stage is neutralized after the prepolymer is dispersed in water.

Water based polyurethane, includingpolyurethane aqueous solution, water dispersion and water emulsion three, for the binary colloidal system, polyurethane (PU) particles dispersed in a continuous water phase, also known as water-based PU or waterborne PU.