Solvent-free polyrethane-polymer-hybrid-dispersion and use thereof

A solvent-free polyurethane-polymer hybrid dispersion having a high solids content of polymer or formulation constituents, prepared by the process of

• a) preparing polyurethane base dispersion by
• a1) reacting from 2 to 40% by weight of a relatively high molecular weight polyol component (A) (i) having two or more hydroxyl groups reactive toward polyisocyanates and a molecular mass of from 500 to 6,000 Dalton and, optionally from 0.1 to 2% by weight of low molecular weight polyol component (A) (ii) having two or more hydroxyl groups that react with polyisocyanates and a molecular mass of from 60 to 150 Dalton with from 2 to 20% by weight of a polyisocyanate component (B) comprising at least one polyisocyanate, polyisocyanate derivative or polyisocyanate homolog having two or more aliphatic or aromatic isocyanate groups, optionally in the presence of a catalyst,
• a2) reacting the polyurethane preadduct from stage a1), which has completely or partly reacted, with from 0.1 to 2% by weight of a low molecular weight and anionically modifiable polyol component (A) (iii) having a molecular mass of from 50 to 250 Dalton and two or more hydroxyl groups reactive toward polyisocyanates and one or more carboxyl groups inert toward polyisocyanates, which can be completely or partly converted into carboxylate groups in the presence of bases,
• a3) reacting the polyurethane prepolymer from stage a2) with from 0.1 to 1.5% by weight of a neutralizing component (C) for complete or partial neutralization of the carboxyl groups, subsequently or simultaneously
• a4) dispersing the neutralized polyurethane prepolymer from stage a3) in from 10 to 60% by weight of water which, if required, also contains from 0.1 to 70% by weight of a formulation component (F) consisting of fillers, pigments, plasticizers, fiber materials and/or other conventional additives for in situ formulation, and then
• a5) reacting the polyurethane prepolymer dispersion from stage a4) with from 0.1 to 2% by weight of a chain-extending component (D) consisting of at least one polyamine having one or more amino groups reactive toward polyisocyanates and, if required, from 0.05 to 1% by weight of a chain stopper component (E) consisting of at least one monoamine having an amino group reactive toward polyisocyanates, and
• b) subsequently preparing a polyurethane-polymer hybrid dispersion by
• b1) mixing the polyurethane base dispersion from stage a5) with a prepared mixture of from 3 to 60% by weight of a monomer component (G) consisting of one or more monomers having one or more double bonds capable of free radical polymerization and from 0.01 to 1% by weight of initiator component (H) consisting of at least one lipophilic free radical initiator which has a half-life of one hour at a decomposition temperature in the range of from 40 to 170° C., and finally
• b2) carrying out a free radical polymerization of the component (G) within the micelles of the polyurethane base dispersing by the thermal decomposition of the component (H), the solids content of polyurethane polymer comprising components (A) to (E) being adjusted to from 40 to 70% by weight, based on the total amount of polyurethane base dispersion.