Ion-exchanged abrasion resistant coatings

• US 5,035,745 A
• Filed: 06/29/1990
• Issued: 07/30/1991
• Est. Priority Date: 06/29/1990
• Status: Expired due to Term

• Current Assignee: PPG Industries Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Incorporated (Nouryon BV)
• Inventors: Lin, Chia-Cheng, Basil, John D., Hunia, Robert M.
• Primary Examiner(s): Morris, Theodore
• Assistant Examiner(s): Brunsman, David M.
• Application Number:
  US07/546,076
• Time in Patent Office: 396 Days
• Field of Search: 106/287.14, 106/287.16, 106/287.17, 106/287.19, 106/634, 106/287.12, 106/287.13, 106/287.18
• US Class Current: 106/287.16
• CPC Class Codes: C08G 77/34 Purification
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 183/04 Polysiloxanes

Abstract

An abrasion resistant and ultraviolet radiation resistant coating is disclosed comprising an inorganic oxide matrix formed by the hydrolysis and condensation of an alkoxysilane and/or other metal alkoxide, further comprising cerium oxide for ultraviolet radiation resistant and/or silica for improved abrasion resistance. A partially hydrolyzed silane sol containing colloidal cerium oxide is ion-exchange with an anion exchange resin in one embodiment. In another a partially hydrolyzed silane sol containing colloidal silica is ion-exchanged to remove sodium ions prior to adding the colloidal ceria resulting in improved properties in the coating composition and resultant coating.

Claims

1. An optically transparent coating composition for protecting a substrate from ultraviolet radiation comprising an ion-exchanged reaction mixture which comprises

a. a partially hydrolyzed alkoxide of the general formula R_X M(OR'"'"')_z-x wherein R is an organic radical, M is selected from the group consisting of silicon, aluminum, titanium, zirconium and mixtures thereof, R'"'"' is a low molecular weight alkyl radical, z is the valence of M and x is less than z and may be zero;

and

b. a colloidal oxide selected from the group consisting of silica and cerium oxide and mixtures thereof.

2. A composition according to claim 1, wherein said alkoxide comprises the general formula R_X Si(OR'"'"')_4-x and R'"'"' is selected from the group consisting of methyl, ethyl, propyl, and butyl.

3. A composition according to claim 2, wherein R is selected from the group consisting of alkyl, vinyl, phenyl, methoxyethyl, γ

-glycidoxypropyl and γ

-methacryloxypropyl, and x is 1.

4. A composition according to claim 3, wherein said alkoxide comprises methyl triethoxysilane.

5. A composition according to claim 3, wherein said alkoxide comprises γ

-glycidoxypropyl trimethoxysilane.

6. A composition according to claim 1, wherein said cerium oxide comprises colloidal particles in aqueous dispersion.

7. A composition according to claim 1, further comprising silica.

8. A composition according to claim 7, wherein said silica comprises colloidal particles in aqueous dispersion.

17. A method according to claim 1, wherein said silica comprises colloidal particles in aqueous dispersion.

18. A method according to claim 17, wherein said silica particles have an average particle size of 10 to 20 microns.

9. A method of preparing an optically transparent abrasion resistant coating composition comprising the steps of:

a. at least partially hydrolyzing an alkoxide of the general formula R_X M(OR'"'"')_z-x wherein R is an organic radical, M is selected from the group consisting of silicon, aluminum, titanium, zirconium and mixtures thereof, R'"'"' is a low molecular weight alkyl radical, z is the valence of M and x is less than z and may be zero;

b. adding colloidal silica to form a silane-silica sol; and

c. ion-exchanging the silane-silica sol to remove sodium ions.

10. The method according to claim 9, wherein the coating composition is made resistant to ultraviolet radiation by the additional steps of:

d. adding to said at least partially hydrolyzed alkoxide a colloidal dispersion of cerium oxide; and

e. ion-exchanging the silane/silica/cerium oxide sol.

11. A method according to claim 10, wherein said alkoxide comprises the general formula R_X Si(OR'"'"')_4-x and R'"'"' is selected from the group consisting of methyl, ethyl, propyl and butyl.

12. A method according to claim 11, wherein R is selected from the group consisting of alkyl, vinyl, phenyl, methoxyethyl, γ

-glycidoxypropyl and γ

-methacryloxypropyl, and x is 1.

13. A method according to claim 12, wherein said alkoxide comprises methyl triethoxysilane.

14. A method according to claim 12, wherein said alkoxide comprises γ

-glycidoxypropyl trimethoxysilane.

15. A method according to claim 10, wherein said cerium oxide comprises colloidal particles in aqueous dispersion.

16. A method according to claim 15, wherein said particles have an average particle size of 5 to 15 microns.