Electrically heated transparent glass article and method of making

• US 4,844,985 A
• Filed: 11/02/1988
• Issued: 07/04/1989
• Est. Priority Date: 10/06/1986
• Status: Expired due to Term

• Current Assignee: Automotive Components Holdings LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Pharms, Eugene P., Amberger, Charles J., Hymore, Ronald R.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Yoder, Michele K.
• Application Number:
  US07/266,436
• Time in Patent Office: 244 Days
• Field of Search: 156/99, 156/106, 156/319, 156/100, 427/419.3, 219/203, 428/426, 428/432, 428/699, 428/437, 428/469
• US Class Current: 428/432
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 3/86 the heating conductors being embedded in the transparent or reflecting material H05B3/845 takes precedence
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

In a transparent glass article comprising an electrically conductive, transparent, metal-based coating on a glass substrate and polyvinyl butyral material (PVB) bonded thereto, adhesion between the coating and the PVB is improved by a thin chromium-based film on the metal-based coating interfacing with the PVB. Adhesion is particularly improved in its resistance to exposure to UV radiation. In an electrically heated windshield application, the adhesion is improved by chromium-based film (24) between the metal-based coating (22) on a first glass template (12) and a PVB interlayer (26) mediate the first glass template and a second glass template (28). The glass article is produced according to a method aspect of the invention.

Claims

1. A transparent glass article comprising:

a glass substrate;

an electrically conductive, transparent, metal-based coating on a surface of said glass substrate;

a chromium-based film over the metal-based coating; and

polyvinyl butyral material bonded to said chromium-based film.

2. The transparent glass article of claim 1 wherein said chromium-based film consists essentially of chromium oxide.

3. The transparent glass article of claim 1 wherein said chromium-based film consists essentially of chromium oxide and chromium.

4. The transparent glass article of claim 1 wherein said metal-based coating comprises a first zinc oxide film immediately adjacent said glass substrate, a silver film over said first zinc oxide film and a second zinc oxide film mediate said silver film and said chromium-based film.

5. The transparent glass article of claim 1 wherein said chromium-based film is from about 25 angstroms to about 100 angstroms thick.

6. The transparent glass article of claim 1 wherein said article is an electrically heated windshield of a motor vehicle.

7. An electrically heated windshield for a motor vehicle, which windshield comprises:

a first glass template having an outboard surface and an oppositely facing inboard surface;

an electrically conductive, transparent, metal-based coating on said inboard surface of said first glass template, said metal-based coating comprising a first zinc oxide film immediately adjacent said inboard surface, a silver film over said first zinc oxide film and a second zinc oxide film over said silver film;

a chromium-based film over said second zinc oxide film;

a layer of polyvinyl butyral material substantially coextensive with said first glass template and having an outboard surface bonded to said chromium-based film; and

a second glass template bonded to an inboard surface of said layer of polyvinyl butyral material.

8. The electrically heated windshield of claim 7 wherein said chromium-based film consists essentially of chromium oxide.

9. The electrically heated windshield of claim 7 wherein said chromium-based film consists essentially of chromium oxide and chromium.

10. The electrically heated windshield of claim 7 wherein said chromium-based film is from about 25 angstroms to about 100 angstroms thick.

11. An electrically heated windshield for a motor vehicle, which windshield comprises:

a first glass template having an outboard surface and an oppositely facing inboard surface;

an electrically conductive, transparent, metal-based coating on said inboard surface of said first glass template, said metal-based coating comprising a first zinc oxide film immediately adjacent said inboard surface, a silver film over said first zinc oxide film and a second zinc oxide film over said silver film;

a chromium-based film consisting essentially of chromium oxide and chromium and being from about 25 to 100 angstroms thick over said second zinc oxide film;

a layer of polyvinyl butyral material substantially coextensive with said first glass template and having an outboard surface bonded to said chromium-based film; and

a second glass template bonded to an inboard surface of said layer of polyvinyl butyral material opposite said outboard surface of said layer.

12. A method of making a transparent glass article having improved adhesion between a coated glass substrate and a layer of polyvinyl butyral material, wherein said coated glass substrate comprises a glass substrate and an electrically conductive, transparent, metal-based coating on a surface of said glass substrate, which method comprises the steps of:

(A) providing said coated glass substrate;

(B) coating said metal-based coating of said coated glass substrate with a chromium-based film; and

(C) bonding said polyvinyl butyral material to said coated glass substrate over said chromium-based film using heat and pressure.

13. The method of claim 12 wherein said chromium-based film consists essentially of chromium oxide.

14. The method of claim 12 wherein said chromium-based film consists essentially of chromium oxide and chromium.

15. The method of claim 12 wherein said metal-based coating comprises a first zinc oxide film immediately adjacent said glass substrate;

a silver film over said first zinc oxide film and a second zinc oxide film over said silver film.

16. The method of claim 12 wherein said (B) step comprises coating said metal-based coating of said glass substrate with a chromium-based film about 25 to 100 angstroms thick.

17. The method of claim 12 wherein said article is an electrically heated windshield of a motor vehicle.

18. A method of improving the adhesion between a transparent and electrically conductive coating on a glass vision unit and polyvinyl butyral material which comprises the steps of:

subjecting the transparent and electrically conductive coating on the glass vision unit to a coating operation in which a thin layer of chromium oxide is placed thereover; and

bonding said chromium oxide coated glass vision unit to the polyvinyl butyral material in a bonding operation employing heat and pressure.

19. A method of making an electrically heated windshield for a motor vehicle, which method comprises the steps of:

(A) providing a coated glass substrate comprising a first glass template and an electrically conductive, transparent, metal-based coating on an inboard surface of said first glass template, said metal based coating comprising a first zinc oxide film immediately adjacent said inboard surface, a silver film over said first zinc oxide film and a second zinc oxide over said silver film;

(B) coating said metal-based coating of said coated glass substrate with a chromium-based film consisting essentially of chromium oxide and chromium and being about 25 to 100 angstroms thick;

(C) laminating a layer of polyvinyl butyral material between said first glass template, said inboard surface thereof toward said layer of polyvinyl butyral material, and a second glass substrate, using heat and pressure.

20. A method of making an electrically heated windshield for a motor vehicle, which method comprises the steps of:

(A) placing bus bars and an electrically conductive, transparent, metal-based coating on an inboard surface of said first glass template, said metal-based coating comprising a first zinc oxide film immediately adjacent said inboard surface, a silver film over said first zinc oxide film and a second zinc oxide over said silver film;

(B) coating said metal-based coating of said coated glass substrate and a chromium-based film consisting essentially of chromium oxide and chromium and being about 25 to 100 angstroms thick;

(C) laminating a layer of polyvinyl butyral material between said first glass template, said inboard surface thereof toward said layer of polyvinyl butyral material, and a second glass substrate, using heat and pressure.