| 摘要 |
The present disclosure presents an improved coating system of two components consisting on the polymers containing crosslinkable hydroxy and a polyisocyanate crosslinker. The improvement has to do with the use of a hydroxy acrylate/polyurethane prepolymer hybrid finished in hydroxy transport by water, preferably a hydroxy acrylate hybrid in combination with a water dispersible polyisocyanate. The coating composition of two components can be prepared by: a) forming a polyurethane prepolymer finished in water dispersible isocyanate containing carboxy, b) adding at least an acrylic monomer containing a hydroxy group to the polyurethane prepolymer finished in water dispersible isocyanate, containing carboxy to form a prepolymer/monomer mixture, c) adding an alkanolamine to the prepolymer/monomer mixture for introducing hydroxy functionality to the polyurethane prepolymer; d) dispersing the prepolymer/monomer mixture in water, e) adding an oil soluble initiator of free radicals and a chai n extender containing hydroxy to the aqueous dispersion, f) polymerization of the acrylic monomers and completing the chain extension within the prepolymer when heating the aqueous dispersion, and g) mixing the resulting hybrid dispersion with a water dispersible polyisocyanate.
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