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.
Photocatalytically active zinc oxide is used as a white pigment for cosmetics, leading to decomposition of a certain degree of sebum on the skin upon exposure to the ultraviolet radiation in sunlight. Herein, as novel white pigments for use in cosmetics, zinc phosphates were prepared from zinc nitrate and various phosphate compounds, viz., phosphoric acid, sodium di-hydrogen phosphate, disodium hydrogen phosphate, sodium pyrophosphate, or sodium triphosphate. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were evaluated. The obtained materials had Zn/P ratios corresponding to those of zinc orthophosphate Zn 3 (PO 4 ) 2 , zinc pyrophosphate Zn 2 P 2 O 7 , and zinc triphosphate Zn 5 (P 3-O 10 ) 2 . The photocatalytic activity of these zinc phosphate particles was low; thus, these pigments should not induce decomposition of sebum on the skin. All samples prepared in this study exhibited high reflectance within the range of visible light.
Abstract:Zinc oxide, which has photocatalytic activity, is used as a white pigment for cosmetics, resulting in a certain amount of sebum on the skin to be decomposed by the ultraviolet radiation in the sunlight. In this work, zinc phosphates as novel white pigments for use in cosmetics were prepared from zinc nitrate and sodium dihydrogen phosphate, and then ball-milled under various conditions. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were studied. The zinc phosphate particle size was decreased by mechanical treatment. In particular, the sample treated with sodium lactate solution had much smaller particles. The milled zinc phosphates exhibited less photocatalytic activity than zinc oxide, and thus should not decompose sebum on the skin. The milled zinc phosphates showed sufficiently high reflectance within the range of visible light to act as novel white pigments. The sample treated with sodium lactate solution had higher water retention than the sample treated with water. Further, the slip resistance and roughness of the powder particles decreased as a result of treatment with sodium lactate solution.
In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid at various Zn/P ratios as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were studied. Samples prepared at Zn/P = 2/1, 3/2, and 1/1 indicated XRD pattern of Zn3(PO4)2•4H2O. The plane particles were observed in SEM images of sample prepared at Zn/P = 2/1, 3/2 and 1/1. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials prepared at Zn/P = 2/1, 3/2 and 1/1 and their thermal products at 100 °C showed a high reflectance within the range of visible light. Samples prepared at high Zn/P ratio indicated small MIU value.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.