u00b0 c until the desired acid number is obtained typically this takes from about one to about ten hours the preferred acid number for the product is from about 140 to about 300 more preferred is from about 160 to about 240 other orders of addition and reaction are possible but they are generally suitable for only certain combinations of reactants other combinations tend to give inhomogeneous products the preferred method is the most generally applicable the aromatic ester modified rosin based resins that are described above are utilized in the present invention in the form of aqueous solutions where they are dissolved in water at a ph of about 7 5 or higher preferably a ph of from about 8 0 to about 10 0 the desired ph is obtained by the addition of a fugitive base such as ammonia an amine or an alkanolamine typical amines that can be used include but are not limited to mono di and trialkylamines containing from one to about 12 carbon atoms morpholine and n alkylmorpholines where the alkyl group contains from one to about four carbon atoms typical alkanolamine that are suitable for use in the invention include but are not limited to monoalkanolamines dialkanolamines trialkanolamines alkyldialkanolamines and dialkylalkanolamines containing.