Preparation of CaCO3/TiO2@SiO2 Pigments by the One-Pot Method: Surface-coated SiO2 Improves the Weatherability of Pigments

In this paper, a CaCO3/TiO2@SiO2 composite pigment (CTS) was prepared by a carbonation reaction using a one-pot method. CTS can reduce the amount of rutile TiO2 needed and improve the weatherability compared with TiO2 and CaCO3/TiO2 (CT). The performance test results showed that the composite pigment with 60% TiO2 has a coating film contrast ratio of 91.05% of pure TiO2, and the oil absorption and whiteness values were also close to those of pure TiO2, indicating that the CTS has good pigment properties. The XPS and infrared results showed that the bonding of CaCO3, TiO2, and SiO2 occurred at the interface. The tight bonding of the three substances was realized through a dehydroxylation reaction on the surface. In addition, the SiO2 layer weaken the photocurrent response of TiO2 in the CTS and reduced the UV absorption of the composite pigment, which slowed the degradation rate of rhodamine B in the composite pigment coatings; thus, the CTS exhibits excellent weatherability performance in coating applications.