| 摘要 |
<p>A process is provided for making an aqueous dispersible, polyurethane or poly(urethane-urea) polymer which has internal pendant, siliconate anions. The aqueous dispersion is prepared from a reaction product of 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 organo silane and also has at least one hydrolyzed or hydrolyzable groups associated with the silicone atom. Optionally, a hydrophilic additive may also be a comonomer in preparing the reaction product. The polymeric reaction product is formed at temperatures less than 200 DEG C. at atmospheric pressure. The polymeric reaction product is combined with water to form an oil-in-water dispersion and the pH of the aqueous dispersion is maintained at least about 7, when the silyl concentration on the reaction product is at least about 0.1 weight percent based on the water in the dispersion. The polymer can be a prepolymer that is chain extended in the aqueous dispersion. The aqueous dispersion can also be prepared from a prepolymer that is devoid of any organosilane used as a comonomer but where the prepolymer is dispersed and chain-extended with an organosilane that is difunctional in the isocyanate polyaddition reaction. The aqueous dispersion of the polyurethane resin is used in coating myriad substrates such as inorganic oxide substrates.</p> |
