Patent ID: 7999050

Claim:
A method of making an aqueous polymer dispersion comprising reacting, in a reactor, a. a non-halogenated acetoacetate group containing monomer, b. at least one additional monomer, c. a base to neutralize the acidic monomer, and d. a molecular weight reducing agent in an amount less than about 0.7 weight percent based on the total weight of the monomers of a molecular weight reducing agent, wherein at least a portion of the base is fed to the reactor during reaction and less than 50% of the base is present in the reactor at the start of the reacting step, and wherein the base is added during the reacting step in an amount such that the pH is not higher than 7 and such that the aqueous polymer dispersion viscosity is lower than an aqueous polymer dispersion prepared in the same way but without the base added during the reacting step.