Solvent-free prepaint for corrosion protection at welds and other repair points on cathodically protected and cathodically unprotected, plastic-sheathed steel pipes

A solvent-free undercoat composition for corrosion control at welds and other repair sites on plastic-sheathed steel pipes with and without cathodic protection, the composition comprising:

• a component K1 being a water-based rubber dispersion with a rubber from the group of butyl, bromobutyl, isoprene or chloroprene rubber or combinations thereof, for formation of a barrier layer for isolating the metallic repair site from oxygen, water vapor and water penetrating from externally;
• a component K2 being a water-based resin dispersion comprising a hydrocarbon resin and/or a natural resin, for adhesion on the metallic surface of the repair site and on the nonpolar surfaces of the plastic sheathing;
• and
• a component K3 being an aqueous emulsion of prehydrolyzed organofunctional silanes for accelerating the drying, for improving the adhesion to the metallic surface, particularly at elevated temperatures, and for increasing the resistance to cathodic disbondment.