A film forming polyurethane dispersion is described comprising a biodegradable polyurethane which is built from at least the following components:a) at least one aliphatic, araliphatic and/or cycloaliphatic polyisocyanate, with an NCO functionality in a range of from 1.8 to 4, preferably of from 2 to 3.b) at least one polyol having a number-average molecular weight Mn of ≥ 330 and ≤ 6000 g/mol, or preferably of ≥ 350 and ≤ 5000 g/mol and a hydroxyl functionality of ≥ 1.5 and ≤ 4,c) optionally at least one amino-functional compound which has at least two isocyanate-reactive amino groups,d) optionally at least one alcohol which has at least two hydroxyl groups and a molar mass of ≥ 62 and ≤ 399 g/mol,e) optionally at least one compound which has one group that is reactive towards isocyanate groups,wherein the polyurethane provides a biodegradation rate according to OECD Guideline 301 B in water of at least 50 % in 28 days. Also the use of the film forming polyurethane dispersion to increase the biodegradation rate of a cosmetic is describes as well as a method to use the polyurethane dispersion for shaping hair styles is described.
