Articles comprising porous coatings

Patent metadata

Field	Value
Publication number	US-9545161-B2
Application number	US-16064407-A
Country	US
Kind code	B2
Filing date	Feb 12, 2007
Priority date	Feb 14, 2006
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

The invention relates to an article comprising a substrate and a nano-porous coating, wherein the reflectivity of the article is less then 2%, and whereby the amount of sodium measured in the coating by XPS is less then 1 wt %, and further to a method of making the article.

First claim

The invention claimed is:

1. A method of making an article with anti-reflective properties comprising the steps of:
(i) reacting nano-particles with an amount of surface modifying agent;
(ii) pre-hydrolysing an inorganic binder;
(iii) mixing the surface modified particles from step (i) with the pre-hydrolysed binder from step (ii) to form a coating composition;
(iv) applying the coating composition to a substrate that includes hygroscopic sodium salt compounds;
(v) forming a cured coating by curing the coating composition and causing the hygrosopic sodum salt compounds to migrate into the cured coating at a curing temperature of between about 200° C. to about 700° C. and causing the hygroscopic sodium salt compounds to migrate into the cured coating;
(vi) washing the cured coating with water or a solvent for the hygroscopic sodium salt compounds for about 30 seconds sufficient to remove the hygroscopic sodium salt compounds from the cured coating and thereby obtain an article having a reflectivity of less than 2% after storage for 28 days and having an amount of sodium measured in the coating by XPS of less than 1 wt %.

2. The method according to claim 1 , wherein the curing temperature of step (v) is between 200° C. and 500° C.

3. The method according to claim 1 , wherein the reflectivity of the article is less than 1%.

4. The method according to claim 1 , wherein the substrate is glass.

5. The method according to claim 4 , wherein the substrate comprises between 0 and 7 wt % of sodium oxide.

6. The method according to claim 1 , which further comprises providing a blocking layer between the coating and the substrate.

7. The method according to claim 6 , wherein the blocking layer comprises CeO 2 .

8. The method according to claim 1 , wherein the coating has an arithmetic average roughness of about 2 to about 50 nm.

9. A method of making an article with anti-reflective properties comprising the steps of:
(i) forming a coating composition by reacting nano-particles with an inorganic binder selected from the group consisting of alkoxy silanes, alkoxy zirconates, alkoxy aluminates, alkoxy titanates, alkyl silicates, sodium silicates and mixtures thereof;
(ii) applying the coating composition to a substrate that includes hygroscopic sodium salt compounds;
(iii) obtaining a cured coating by curing the applied coating composition at a curing temperature between about 200° C. to about 700° C. to form a porous coating and causing the hygroscopic sodium salt compounds to migrate into the cured coating; and
(iv) washing the cured coating with water or a solvent for the hygroscopic sodium salt compounds for about 30 seconds sufficient to remove the hygroscopic sodium salt compounds and thereby obtain an article having a reflectivity of less than 2% after storage for 28 days and having an amount of sodium measured in the coating by XPS of less than 1 wt %.

10. The method according to claim 9 , wherein the curing temperature of step (iii) is between 200° C. and 500° C.

11. The method according to claim 9 , wherein the reflectivity of the article is less than 1%.

12. The method according to claim 9 , wherein the substrate is glass.

13. The method according to claim 12 , wherein the substrate comprises between 0 and 7 wt % of sodium oxide.

14. The method according to claim 9 , which further comprises providing a blocking layer between the coating and the substrate.

15. The method according to claim 14 , wherein the blocking layer comprises CeO 2 .

16. The method according to claim 9 , wherein the coating has an arithmetic average roughness of about 2 to about 50 nm.

17. The method according to claim 9 , wherein the inorganic binder is tetra alkoxy silane.

18. The method according to claim 9 , wherein the inorganic binder is present in the coating composition in an amount of 1% to 40%, by weight of solids.

19. The method according to claim 9 , wherein step (iv) comprises drying the cured coating in ambient air for about 1 hour after washing.

20. The method according to claim 9 , wherein step (iv) is practiced by washing the cured coating with a dilute acid solvent for hygroscopic salt compounds selected from the group consisting of formic acid, acetic acid, benzoic acid, sulphuric acid, nitric acid, hydrochloric acid and phosphoric acid.

Assignees

• Thies Jens Christoph
• Vrijaldenhoven Patrick Wilhelmus Antonius
• Langermans Hermanus Adrianus
• Dsm Ip Assets Bv

Inventors

• Thies Jens Christoph
• Vrijaldenhoven Patrick Wilhelmus Antonius
• Langermans Hermanus Adrianus

Classifications

• G02B1/11 Primary

  Anti-reflection coatings · CPC title

• Y10T428/31507

  Of polycarbonate · CPC title

• A47G1/06 Primary

  Picture frames (making from paper B31D) · CPC title

• Y10T428/24355

  Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] · CPC title

• Y10T428/31786

  Of polyester [e.g., alkyd, etc.] · CPC title