title: Influence of pH, concentration of sodium lactate as an additive and ultrasonic treatment on synthesis of zinc phosphate white pigments.
abstract: Zinc oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid at pH 5 and 7 with and without the addition of sodium lactate and ultrasonic treatment as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, colour phase, moisture retention and smoothness of the zinc phosphates were studied. The obtained materials had a Zn/P ratio of about 1.5, which corresponds to zinc orthophosphate Zn3 (PO4 )2 . Samples prepared with ultrasonic treatment indicated the high ratios of large particles in scanning electron microscopy images and particle-size distributions. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials obtained and their thermal products at 100°C showed a high reflectance within the range of visible light. The slipping resistance and roughness of the powder were enough low for use in cosmetics.
authors.affiliation: Department of Informatics and Environmental Sciences, Kyoto Prefectural University, 1-5, Shimogamo Nakaragi-cyo, Sakyo-ku, Kyoto, 606-8522, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Onoda
authors.forename: M
authors.initials: M
authors.lastname: Haruki
authors.forename: T
authors.initials: T
authors.lastname: Toyama
mesh_terms: D004396:Coloring Agents / Q000138:chemical synthesis* / Q000737:chemistry; D003358:Cosmetics / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D010710:Phosphates / Q000138:chemical synthesis* / Q000737:chemistry; D019354:Sodium Lactate / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014463:Ultrasonography; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D003358:Cosmetics; D010710:Phosphates; D017967:Zinc Compounds; C043952:zinc phosphate; D019354:Sodium Lactate
keywords: particle shape; photocatalytic activity; water retention; white pigment; zinc phosphates