Process for preparing printing ink binders, and their use in printing inks

Process for preparing printing ink binders based on reaction products of (a) natural resins, a copolymer (b+c) of (b) polymerizable hydrocarbons having isolated C5 rings and (c) alpha , beta -olefinically unsaturated carboxylic acid units and (d) calcium compounds and, if appropriate, other compounds of metals of group II of the periodic system. The compounds (a) to (c) are reacted to give a product having an acid number of 75 to 150, which is then reacted with metal compounds in such a way that the acid number is reduced by at least one third. Unreacted metal compounds present in the resulting reaction product are then converted by means of acetic acid, via acetates, into salts of the resins. The resulting binders are used for preparing printing inks.