Asymmetric dialdimine-containing polyurethane composition

A composition comprising

• a) a polyurethane polymer PUP that is based on at least one polyisocyanate P having aromatic isocyanate groups, at least one polyether diol, and/or at least one polyether triol, and
• b) at least one dialdimine A of the formula (I),
• wherein X is the radical of a diamine DA with two primary amino groups after the removal of these two amino groups;
• and
• Y1 and Y2 are either
• each independently a monovalent hydrocarbon radical having 1 to 12 carbon atoms,
• or together are a divalent hydrocarbon radical which has 4 to 20 carbon atoms;
• and
• Y3 is a monovalent hydrocarbon radical or is a monovalent hydrocarbon radical having at least one heteroatom;
• with the proviso that at least one of the two primary amino groups of the diamine DA is an aliphatic amino group, and the two primary amino groups of the diamine DA differ from one another
• either
• in the number of hydrogen atoms on the carbon atoms (Ca) in the a position to the particular amino group by at least one
• or
• in the number of hydrogen atoms on the carbon atoms (Cb) in the b position to the particular amino group by at least two.