Method of forming an inorganic oxide coating on a monolith article

Patent metadata

Field	Value
Publication number	US-12201969-B2
Application number	US-202217820290-A
Country	US
Kind code	B2
Filing date	Aug 17, 2022
Priority date	Aug 27, 2021
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A method of forming an inorganic oxide coating on a monolith article to produce a coated monolith article suitable for the treatment of an exhaust gas comprises spraying, as a dry particulate aerosol, inorganic particles and a silicone resin to form a coating layer. The present invention also provides an uncalcined porous monolith article for use in forming a monolith article for the treatment of an exhaust gas. The uncalcined monolith article comprises a dry particulate composition comprising inorganic particles and a silicone resin.

First claim

The invention claimed is:

1. A method of forming an inorganic oxide coating on a monolith article for the treatment of an exhaust gas, the method comprising:
providing a porous monolith article comprising a plurality of channels for the passage of an exhaust gas, each channel having a gas-contacting surface;
spraying onto the gas-contacting surface, as a dry particulate aerosol, inorganic particles and a silicone resin to form a coating layer; and
calcining the coating layer to provide a coated monolith article.

2. The method according to claim 1 , wherein the monolith article is a catalytic wall-flow filter.

3. The method according to claim 1 , wherein either:
(i) the inorganic particles are sprayed onto the gas-contacting surface as a first dry particulate aerosol to form an inorganic particle layer and the silicone resin is then sprayed onto the inorganic particle layer as a second dry particulate aerosol to form the coating layer; or
(ii) a mixture of the inorganic particles and silicone resin is sprayed onto the gas-contacting surface as a dry particulate aerosol to form the coating layer.

4. The method according to claim 1 , wherein the silicone resin has a molecular weight of greater than 10,000, and less than 200,000.

5. The method according to claim 1 , wherein the silicone resin has a glass transition temperature (Tg) of greater than 30° C. and less than 80° C.

6. The method according to claim 1 , wherein the silicone resin has the formula [R x SiX y O z ] n , wherein R is an alkyl or aryl, X is a functional group bonded to silicon, and wherein z is more than 1 and less than 2.

7. The method according to claim 6 , wherein y is less than 1 and/or wherein y is less than x.

8. The method according to claim 6 , wherein the silicone resin has a degree of crosslinking of greater than 65%, and less than 80%.

9. The method according to claim 6 , wherein R is one or more of C 1 -C 6 alkyls and phenyl.

10. The method according to claim 6 , wherein X is one or more of OH and C 1 -C 6 alkoxy.

11. The method according to claim 1 , wherein the silicon dioxide content of the silicone resin is greater than 80 wt %.

12. The method according to claim 1 , wherein the inorganic particles are selected from the group consisting of zeolites, refractory oxides, and their mixtures.

13. The method according to claim 12 , wherein the inorganic particles are refractory oxide particles comprising calcium aluminate, fumed alumina, fumed silica, fumed titania, fumed zirconia, fumed ceria, alumina aerogel, silica aerogel, titania aerogel, zirconia aerogel, ceria aerogel or a mixture thereof.

14. The method according to claim 1 , wherein the inorganic particles have a d 50 by volume of greater than 0.2 μm and less than 25 μm.

15. The method according to claim 1 , wherein a mixture of the inorganic particles and silicone resin is sprayed onto the gas-contacting surface as a dry particulate aerosol to form the coating layer, and wherein in the mixture, the ratio of inorganic particles to silicone resin, by weight, is greater 0.9, and less than 2.5.

16. The method according to claim 1 , wherein calcining comprises heating to a temperature of at least 400° C., and at most 530° C.

17. The method according to claim 1 , wherein the monolith article comprises one or more platinum group metals.

18. The method according to claim 1 , wherein the dry particulate aerosol is formed from a dry particulate composition having a tapped density of less than 1.5 g/cm 3 .

Assignees

• Johnson Matthey Plc

Inventors

• Arulraj Kaneshalingam
• Bellham Peter
• De Bruin Alexander
• Chandler Guy Richard
• Corrigan Chris
• Marvell David
• Turner John

Classifications

• B01J35/56

  Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths · CPC title

• B01J37/082

  Decomposition and pyrolysis · CPC title

• B01J37/0219 Primary

  the coating containing organic compounds · CPC title

• B01J29/7015

  CHA-type, e.g. Chabazite, LZ-218 · CPC title

• B01J29/7007

  Zeolite Beta · CPC title