An aqueous polymer composition comprising (i) 5 to 30 wt.% of polyurethane obtained by the reaction of: (a) 9 to 31 wt.% of at least one polyisocyanate; 0 to 8 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol, containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol not comprised by; where and add up to 57 to 91 wt.%; 0 to 10 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol not comprised by; where,,, and add up to 100%; and (b) at least one chain-extending compound; where the acid value of the resulting polyurethane (i) is between 3 to 40 mg KOH/g; (ii) 70 to 95 wt.% of vinyl polymer comprising (c) 20 to 90 wt.% of vinyl polymer with Tg < 20 °C, as determined according the description; (d) 10 to 80 wt.% of vinyl polymer with Tg ≥ 20 °C; wherein (c) and (d) add up to 100%; where at least one of (c) and (d) contains acid functional groups with an acid value in the range of from 15 to 240 mg KOH/g, as determined according the description; and wherein (i) and (ii) add up to 100%. (i) 5 to 30 wt.% of polyurethane obtained by the reaction of: (a) 9 to 31 wt.% of at least one polyisocyanate; 0 to 8 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol, containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol not comprised by; where and add up to 57 to 91 wt.%; 0 to 10 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol not comprised by; where,,, and add up to 100%; and (b) at least one chain-extending compound; where the acid value of the resulting polyurethane (i) is between 3 to 40 mg KOH/g; (a) 9 to 31 wt.% of at least one polyisocyanate; 0 to 8 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol, containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol not comprised by; where and add up to 57 to 91 wt.%; 0 to 10 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol not comprised by; where,,, and add up to 100%; and 9 to 31 wt.% of at least one polyisocyanate; 0 to 8 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol, containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol containing ionic or potentially ionic water-dispersing groups; 0 to 91 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 501 to 5000 g/mol not comprised by; where and add up to 57 to 91 wt.%; 0 to 10 wt.% of at least one isocyanate-reactive compound with a weight average molecular weight in the range of from 50 to 500 g/mol not comprised by; where,,, and add up to 100%; and (b) at least one chain-extending compound; where the acid value of the resulting polyurethane (i) is between 3 to 40 mg KOH/g; (ii) 70 to 95 wt.% of vinyl polymer comprising (c) 20 to 90 wt.% of vinyl polymer with Tg < 20 °C, as determined according the description; (d) 10 to 80 wt.% of vinyl polymer with Tg ≥ 20 °C; wherein (c) and (d) add up to 100%; where at least one of (c) and (d) contains acid functional groups with an acid value in the range of from 15 to 240 mg KOH/g, as determined according the description; and wherein (i) and (ii) add up to 100%. (c) 20 to 90 wt.% of vinyl polymer with Tg < 20 °C, as determined according the description; (d) 10 to 80 wt.% of vinyl polymer with Tg ≥ 20 °C;