Process for the preparation of air-drying aqueous binder emulsions and their use in the formulation of aqueous dipping paints

摘要

The invention relates to a process for the preparation of aqueous binder emulsions drying in the air, based on condensation products of specific emulsifier resins with urethane alkyd resins or urethane oils, which are particularly suitable for the formulation of aqueous dip-coating compositions. The properties necessary for application by coating are achieved by the use of an emulsifier component which is an oligoester of unsaturated fatty acids modified with at least 10 % by weight of (meth)acrylic acid and other comonomers and whose acid number of 70 to 140 mg of KOH/g derives exclusively from the (meth)acrylic acid employed for modification. The emulsifier component is partially condensed with a urethane alkyd resin and/or a urethane oil, an in-situ process for urethanisation of the urethane component in the presence of the emulsifier component and for subsequent condensation also being possible. The neutralising agent employed is preferably ammonia.