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Three novel UV curable polymeric dyes (UVPDs) based on multifunctional waterborne polyurethanes have been successfully developed to overcome the drawbacks of thermo-curing. The functionality of the UVPDs is tailored by end-capping with 2-hydroxyethyl acrylate (HEA), pentaerythritol triacrylate (PETA) and dipentaerythritol pentaacrylate (DPEPA). The chemical structure, molecular weight and carbon–carbon double bond (CC) content of the UVPDs were investigated. The thermal properties, curing behavior and color properties of the UVPDs are also discussed. It is found that the thermal stability of the UVPDs is improved upon increasing the functionality. The incorporation of chromophores into the polyurethane chain reduces the curing efficiency. The curing behavior observations demonstrate that the UVPDs can cure rapidly upon UV irradiation, especially the ones with higher functionality. A higher degree of cross-linking and better water resistance are obtained when UVPD films are cured with 5% photoinitiator. Furthermore, the UVPDs show outstanding UV light stability. The maximum absorption wavelength and curve trend of the cotton fabrics coated with the UVPDs remain unchanged while the color of the coated cotton fabrics slightly lightens when prolonging the UV curing time. The color fastness to rubbing and washing of the coated cotton fabrics with UVPD10 can be enhanced up to 4–5 grade after curing for 60 s.

A waterborne polyurethane covalently bonded anthraquinone dye chromophore was successfully synthesized via incorporating micromolecule Disperse Red 91 into the polyurethane skeleton. The number- and weight-average molecular weights of the waterborne polyurethane based polymeric dye were about 6.57k and 10.3k, respectively. The maximum absorption wavelengths are 260 nm, 520 nm and 555 nm, which show a hypsochromic effect compared with the corresponding micromolecule dye. Thermal stability and centrifugal stability can be distinctly enhanced after the micromolecule dyes are covalently bonded to the polyurethane skeleton. The solubility of waterborne polyurethane based polymeric dye also offers reversibility and good color stability at different pH values. Thermal migration properties of this polymeric dye are improved by 82.4%, compared to that of a simple mixture of dye and polyurethane. The polymeric dye with enhanced color stability under centrifugation, acid, alkaline and thermal conditions can upgrade the product quality as it is employed in dyeing, coating or printing ink.