Particulate metal oxide particles comprising a metal oxide core and a coating layer comprising an inorganic material, a silane coupling agent and/or a hydrophobizing agent

Patent metadata

Field	Value
Publication number	US-10869826-B2
Application number	US-201314418999-A
Country	US
Kind code	B2
Filing date	Jul 19, 2013
Priority date	Aug 6, 2012
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

Abstract

A particulate metal oxide has a metal oxide core and a coating layer containing an inorganic material and (i) a quaternary silane coupling agent, and/or (ii) a silane coupling agent and a hydrophobizing agent. Preferred materials are titanium dioxide core particles, an amino organosilane coupling agent and a fatty acid hydrophobizing agent. The particulate metal oxide is suitable for use in forming a dispersion, and the particles and dispersion can be used in an end-use sunscreen composition which is transparent, exhibits effective UV absorption properties, reduced photoactivity, and/or improved skin feel.

First claim

The invention claimed is:

1. Coated metal oxide particles comprising metal oxide core particles each having thereon a coating layer comprising silica, a fatty acid and/or a salt thereof and a silane coupling agent,
wherein
the metal oxide comprises titanium dioxide,
the silane coupling agent comprises at least one hydrolyzable group and an amine group,
the coated metal oxide particles have an E 308 /E 524 ratio of greater than 20, and
the coated metal oxide particles have a BET specific surface area in a range from 75 to 100 m 2 g −1 .

2. The coated metal oxide particles of claim 1 , wherein the fatty acid has 10 to 24 carbon atoms.

3. The coated metal oxide particles of claim 1 , wherein the coating layer comprises 0.5% to 35% by weight of the silica, and/or 0.5 to 20% by weight of silane coupling agent, and/or 0.5% to 20% by weight of fatty acid and/or salt thereof, all based on the weight of the metal oxide core particles.

4. The coated metal oxide particles of claim 1 , comprising 82% to 84% by weight of the metal oxide, 6.5% to 7.5% by weight of the silica, 4% to 5.5% by weight of silane coupling agent, and 4.5% to 6% by weight of fatty acid and/or salt thereof, all based on the total dry weight of the particles.

5. The coated metal oxide particles of claim 1 , having a median volume particle diameter in dispersion of 40 to 55 nm.

6. The coated metal oxide particles of claim 1 , having a BET specific surface area in a range from 85 to 90 m 2 g −1 .

7. The coated metal oxide particles of claim 1 , having a maximum extinction coefficient (E max ) in the range from 50 to 68 l/g/cm.

8. A dispersion comprising the coated metal oxide particles of claim 1 in a liquid dispersing medium, wherein the liquid dispersing medium is a cosmetically acceptable material.

9. The dispersion of claim 8 , which comprises at least 30% by weight of the coated metal oxide particles.

10. The dispersion of claim 8 , which comprises a dispersing agent.

11. A method of making the coated metal oxide particles of claim 1 , comprising:
(i) forming metal oxide core particles, and
(ii) applying a coating layer to the metal oxide core particles comprising silica, the silane coupling agent, and the fatty acid and/or salt thereof.

12. The method of claim 11 , wherein the coating layer is applied sequentially in the order of (1) silica, (2) silane coupling agent, and (3) fatty acid and/or salt thereof.

13. A sunscreen composition comprising the coated metal oxide particles of claim 1 .

14. A method of improving skin feel in a sunscreen composition comprising applying to the skin a composition comprising coated metal oxide particles of claim 1 .

15. The method of claim 14 , wherein the improved skin feel includes a higher degree of lubricity to the skin.

16. A composition comprising:
(i) coated metal oxide particles comprising metal oxide core particles each having thereon a coating layer comprising silica, a fatty acid and/or a salt thereof and a silane coupling agent,
wherein
the metal oxide comprises at least one member selected from the group consisting of titanium dioxide, zinc oxide and iron oxide,
the silane coupling agent comprises at least one hydrolyzable group and an amine group, and
the coated metal oxide particles have a BET specific surface area in a range from 75 to 100 m 2 g −1 ; and

(ii) a liquid medium selected from the group consisting of a C12-C15 alkyl benzoate, a fatty acid glyceride and isohexadecane.

Assignees

• Croda Int Plc

Inventors

• Sayer Robert Michael
• Tooley Ian Robert
• Staniland Paul Martin

Classifications

• A61K8/29 Primary

  Titanium; Compounds thereof · CPC title

• A61K2800/63

  More than one coating · CPC title

• C09C3/08

  Treatment with low-molecular-weight {non-polymer} organic compounds {(C09C3/006, C09C3/048 take precedence)} · CPC title

• A61K8/361

  Carboxylic acids having more than seven carbon atoms in an unbroken chain; Salts or anhydrides thereof · CPC title

• C09C1/3661

  Coating · CPC title