Synthetic resin containing quaternary ammonium groups, its preparation, and pigment paste produced using this resin

A water-dilutable synthetic resin containing quaternary ammonium groups, which furthermore contains one or more basic secondary or tertiary amino groups or secondary and tertiary amino groups per quaternary ammonium group, and is an adduct of

• (A) a quaternary ammonium salt having a molecular weight of about 175-1200, which is prepared by reacting
• (a) an organic compound possessing two or more basic amino groups per molecule, one of which is a primary group and is protected as a ketimine by prior reaction with a ketone, and the remaining basic amino groups are tertiary groups with
• (b) from 15 to 100 mol %, based on the nitrogen atoms of component (a), of an organic or inorganic acid and
• (c) from 15 to 100 mol %, based on the nitrogen atoms of component (a), of one or more monoepoxide compounds, and, if required, eliminating the protective group hydrolytically, and
• (B) a resin which has a mean molecular weight M.sub.w of from 300 to 6000 and contains on average from 1.5 to 3.0 epoxide groups per molecule, and, if necessary,
• (C) one or more monofunctional organic compounds whose functional group is capable of undergoing an addition reaction with an epoxide, with the exception of tertiary amines and their salts.