Optically transparent UV-protective coatings

• US 6,355,189 B1
• Filed: 02/16/2000
• Issued: 03/12/2002
• Est. Priority Date: 10/03/1986
• Status: Expired due to Fees

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Basil, John D., Hunia, Robert M., Lin, Chia-Cheng
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US09/504,453
• Time in Patent Office: 755 Days
• Field of Search: 252/582, 252/588, 252/589, 106/287.12, 106/287.13, 106/287.14, 106/287.15, 106/287.16, 106/287.18
• US Class Current: 252/588
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence

Abstract

An ultraviolet radiation resistant coating is disclosed comprising cerium oxide in an inorganic oxide matrix formed by the hydrolysis and condensation of an organoalkoxysilanie and/or other metal alkoxide in combination with the reaction product of cerium oxide and tetraalkylsilicate.

Claims

1. A method of preparing an optically transparent ultraviolet resistant coating composition comprising the steps of:

a. at least partially hydrolyzing an alkoxide of the general formula R_xM(OR′

)<sub>z−

x</sub> 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 except when M is silicon; and

b. adding to said at least partially hydrolyzed alkoxide a reaction product of tetraalkylsilicate and cerium oxide.

2. A method according to claim 1, wherein said alkoxide comprises the general formula R_xSi(OR′

)<sub>4−

x</sub> and R′

is selected from the group consisting of methyl, ethyl, propyl and butyl.

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

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

-glycidoxypropyl trimethoxysilane.

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

7. A method according to claim 6, wherein said particles have an average particle size of less than 10 nanometers.

8. A method according to claim 1, further comprising the step of adding silica to said partially hydrolyzed alkoxide.

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

10. A method according to claim 9, wherein said silica particles have an average particle size of 10 to 20 nanometers.

12. A method according to claim 6, wherein said cerium oxide colloidal particles in aqueous dispersion is present in an amount of about 10 to 30 percent by weight.

11. A method of preparing an optically transparent ultraviolet resistant coating composition comprising the steps of:

a. at least partially hydrolyzing an alkoxide of the general formula R_xM(OR′

)<sub>z−

x</sub> 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 except when M is silicon; and

b. adding to said at least partially hydrolyzed alkoxide a reaction product of tetraalkylsilicate and cerium oxide formed from combining tetraalkylsilicate and cerium oxide, increasing the pH, and adding water.