An aqueous polyurethane resin dispersion, the polyurethane resin is obtainable by reacting an allophanate based isocyanate according to general formula I or II, optionally a polyether diol, a polyol containing a quaternary N-atom or tertiary amino group and a polyol selected from the group consisting of polyester polyol, polyether polyol, polycarbonate polyol, a polyacrylate polyol, a polyolefin and a polyamide polyol. The polyurethane resin is suitable as a resin in treatment liquids of substrates and images made by inkjet printing.

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