| 摘要 |
An aqueous dispersible, isocyanate-containing polymer or prepolymer or chain extended polymer is provided which has internal pendant, reactable silane groups and which can also have internal dispersing aids. The aqueous dispersible, isocyanate-containing polymer, prepolymer, or chain extended polymer produces an aqueous dispersion of a polyurethane polymer having pendant reactable siliconate anions. The isocyanate-containing polymer is prepared from polyisocyanates, organic compounds with at least 2 active hydrogens, and organosilane which is at least monofunctional in reaction with isocyanate groups on at least one organic moiety of the organosilane. The organosilane also may have hydrolyzed or hydrolyzable groups associated with the silicone atom. The prepolymer is formed at temperatures less than 200 DEG C. at atmospheric pressure in a one shot or two step process. The polymer is combined with water to form an oil-in-water dispersion, and, if it is a prepolymer, the molecular weight is increased through chain extension. The pH of the aqueous dispersion of the polyurethane is maintained at least around 7 when the silyl concentration of the polymer is greater than 0.1 weight percent of the water in the dispersion. The aqueous dispersion can also be prepared from a prepolymer that is devoid of any organosilane used as a comonomer and where the prepolymer is dispersed and chain-extended with the difunctional organo silane. The aqueous dispersion of the polyurethane resin is used in coating myriad substrates such as inorganic oxide substrates.
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