Zinc oxide particle, method for producing the same, ultraviolet shielding agent, and cosmetic

Patent metadata

Field	Value
Publication number	US-9775787-B2
Application number	US-201415107823-A
Country	US
Kind code	B2
Filing date	Dec 25, 2014
Priority date	Dec 27, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

It is one of the objects of the present disclosure to provide hexagonal prism-shaped zinc oxide particles having improved ultraviolet shielding ratio at the wavelength of 400 nm or less without impairing the direct transition properties of electronic excitation thereof and having remarkably improved ultraviolet shielding ratio for UV-B radiation and UV-A radiation; and a zinc oxide particle containing a solid solution of a Ti element and/or a Fe element and a Zn element in at least a portion thereof, and having a hexagonal prism shape.

First claim

The invention claimed is:

1. A coated zinc oxide particle comprising a zinc oxide particle and a layer covering a surface of the zinc oxide particle,
wherein the zinc oxide particle has a hexagonal prism shape with an aspect ratio of less than 2.5 and a primary particle diameter of 0.01 μm to 100 μm, and
the layer is formed essentially of Zn 2 TiO 4 and/or ZnFe 2 O 4 .

2. The coated zinc oxide particle according to claim 1 , wherein an amount of a Ti element and/or a Fe element is 5 wt % or more and 30 wt % or less relative to 100 wt % of the zinc oxide particle in terms of TiO 2 and/or Fe 2 O 3 .

3. A method for producing the coated zinc oxide particle according to claim 1 , comprising a step (1-1) of adding an aqueous solution of a titanium salt and/or an iron salt and an alkaline aqueous solution to a water-based slurry of raw zinc oxide particles having a hexagonal prism shape at a temperature of 10° C. to 90° C. while keeping a pH at 9±3, and a step (1-2) of baking the coated zinc oxide particle obtained in the step (1-1).

4. A method for producing the coated zinc oxide particle according to claim 1 comprising a step (2-1) of adding raw zinc oxide particles to an aqueous solution of zinc salt obtained by dissolving a titanium salt and/or an iron salt and heat aging, and a step (2-2) of baking the titanium hydroxide-containing zinc oxide particle and/or iron hydroxide-containing zinc oxide particle obtained in the step (2-1).

5. A coated zinc oxide particle obtained by the method according to claim 3 .

6. An ultraviolet shielding agent comprising the coated zinc oxide particle according to claim 1 .

7. A cosmetic comprising the coated zinc oxide particle according to claim 1 .

Assignees

• Sakai Chemical Industry Co

Inventors

• Sueda Satoru
• Hashimoto Mitsuo
• Wada Mizuho

Classifications

• A61K2800/621

  by inorganic compounds · CPC title

• A61K8/29

  Titanium; Compounds thereof · CPC title

• C01P2004/64

  Nanometer sized, i.e. from 1-100 nanometer · CPC title

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title

• A61Q17/04

  Topical preparations for affording protection against sunlight or other radiation; Topical sun tanning preparations · CPC title