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 a repair site 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 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 a surface of the repair site and on a nonpolar surface of the plastic sheathing;
• and
• a component K3 being an aqueous emulsion of prehydrolyzed organofunctional silanes,
• wherein the following fractions of the components, specified in each case as solids content are based on a total mass of the solvent-free undercoat:
• component K1 with a fraction of 10 wt % to 60 wt %;
• component K2 with a fraction of 20 wt % to 90 wt %;
• and
• component K3 with a fraction of 0.1 wt % to 10 wt %.

An undercoat composition, comprising:

• 10 wt % to 60 wt % of a water-based rubber dispersion with a rubber from the group of butyl, bromobutyl, isoprene or chloroprene rubber or combinations thereof;
• 20 wt % to 90 wt % of a tackifies comprising a water-based resin dispersion comprising a hydrocarbon resin and/or a natural resin;
• and
• 0.1 wt % to 10 wt % of an aqueous emulsion of prehydrolyzed organofunctional silanes.