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Influence of pH, concentration of sodium lactate as an additive and ultrasonic treatment on synthesis of zinc phosphate white pigments
Author(s) -
Onoda H.,
Haruki M.,
Toyama T.
Publication year - 2014
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/ics.12129
Subject(s) - zinc , zinc phosphate , nuclear chemistry , chemistry , zinc nitrate , pigment , phosphoric acid , phosphate , photocatalysis , sodium nitrate , inorganic chemistry , mineralogy , organic chemistry , catalysis
Summary 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 Zn 3 (PO 4 ) 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.