Use of aqueous polyurethane dispersions is formulations for sports floor coverings

A method for making sports floor coverings comprising applying a formulation to a surface, said formulation comprising aqueous, isocyanate free polyurethane dispersions, wherein said dispersions have a solid matter content of ≧30 percent by weight and a solvent content of ≦10 percent by weight and wherein the polyurethane polymers of said dispersions have a number average molecular mass of 25,000 to 100,000 Daltons, and are obtained from polyols and polyisocyanates having an NCO/OH equivalent ratio of 1.5 to 2.5;

• wherein said dispersions are produced by a production method comprising the steps of:
• a) reacting 10-50 wt % of higher number average molecular weight polyol component (A) (i) having two or more hydroxyl groups reactive with polyisocyanates and a molecular weight of 250 to 20,000 Daltons, and optionally 0.50-5 wt % lower number average molecular weight polyol component (A) (ii) having two or more hydroxy groups reactive with polyisocyanates and having a molecular weight of 60 to 250 Daltons with 5-25 wt % of polyisocyanate component (B), consisting of at least one polyisocyanate homolog with two or more aliphatic or aromatic isocyanate groups, optionally in the presence of a catalyst, to create a polyurethane pre-adduct, then
• b) reacting the polyurethane pre-adduct of step a) with 0.5-5 wt % of lower number average molecular weight and anionic modifiable polyol component (A) (iii) having two or more hydroxy groups reactive with polyisocyanates and one or more carboxy groups inert with respect to polyisocyanates, which in the presence of base may be completely or partially converted into carboxylate groups, to produce the corresponding prepolymer,
• c) reacting the prepolymer of step b) with 0.25-2.5 wt % of a neutralizing component (C) for the complete or partial neutralization of the carboxy groups, followed by or simultaneous with
• d) dispersing the neutralized prepolymer of step c) in 10-60 wt % water, which optionally contains 10-70 wt % of formulation component (F) consisting of filler material, pigments, softeners, fiber materials, and other common additives, following which
• e) reacting the dispersion of step d) with 0.25-2.5 wt % chain extension component (D) consisting of at least one diamine with two amino groups reactive with polyisocyanate, and
• f) optionally reacting the dispersion of step e) with 0.05-0.5 wt % of chain stopping component (E) consisting of at least one monoamine with an amino group reactive with polyisocyanate,
• wherein the wt % values in steps (a)-(f) are based on the overall weight of said dispersions produced.