A core-shell composite pigment with rutile TiO2 intensification for UV inhibition

Abstract Organic pigments generally have bright colors but poor ultraviolet (UV) resistance. To improve the UV resistance and extend the applications, a core-shell composite pigment with rutile TiO2 intensification for UV inhibition is proposed by a facile sol-gel method in this work. A core-shell structure, with a homogeneous sol-gel TiO2 shell containing additional nanosized rutile TiO2 particles and with the pigment as the core, was established taking advantage of UV resistance of TiO2 and binding ability of sol-gel. While the sol-gel TiO2 shell alone has already shown obvious ultraviolet shielding effect, as tested over different sol-gel aging times and TiO2 loadings, the UV resistance of the fluorescent pigments was further enhanced by binding the nanosized rutile TiO2 in the sol-gel shell. At a sol-gel TiO2 to rutile TiO2 ratio of 2:1, the UV exposure time is extended about eight times compared with that of the original pigment and twice as that of the modified pigment with pure sol-gel TiO2 for the same color change. Therefore, the novel core-shell composite pigment intensified with nanosized rutile TiO2 particles is proved to be efficient in improving the UV resistance of organic pigments.