Gray glass composition

• US 6,274,523 B1
• Filed: 09/15/1995
• Issued: 08/14/2001
• Est. Priority Date: 11/16/1993
• Status: Expired due to Fees

• Current Assignee: Vitro Flat Glass LLC (Compagnie De Saint-Gobain)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Haskins, David R., Longobardo, Anthony V., Shelestak, Larry J., Krumwiede, John F.
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US08/529,039
• Time in Patent Office: 2,160 Days
• Field of Search: 501/70, 501/71
• US Class Current: 501/71
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 4/02 for coloured glass

Abstract

The present invention provides a glass composition having a neutral gray color and a luminous (visible) transmittance within a range that allows the glass to be used as privacy glazing in a vehicle. The glass of the present invention has a standard soda-lime-silica flat glass base composition and uses iron, cobalt and selenium, and optionally nickel, as the colorants. It has also been found that a nickel-free, neutral gray colored glass with a luminous transmittance (C.I.E. illuminant A) of up to 40% at a thickness of 3.9 millimeters may be attained by using as colorants: 0.59 to 0.99 wt. % of the total glass Fe₂O₃ (total iron), no greater than 0.30 wt. % FeO; 60 to 180 PPM CoO and 5 to 30 PPM Se. It has been found that a nickel-bearing, neutral gray colored glass with a luminous transmittance (C.I.E. illuminant A) of up to but less than 40% at a thickness of 3.9 millimeters may be attained by using as colorants: 0.35 to 1.1 wt. % of the total glass Fe₂O₃ (total iron), no greater than 0.30 wt. % FeO; 60 to 180 PPM CoO; 1 to 30 PPM Se; and 25 to 550 PPM NiO.

Claims

1. A neutral gray colored glass composition having a base glass portion comprising:

2. The composition as in claim 1 wherein the FeO concentration is from 0.181 to 0.24 weight percent and the Se concentration is from 14 to 24 PPM.

14. A glass sheet made from the composition as recited in claim 1.

15. The glass sheet as in claim 14 wherein the sheet has a thickness between 3 to 6 mm.

16. The glass sheet as in claim 14 wherein the color of the glass has dominant wavelengths in the range of 502 to 540 nanometers and an excitation purity of no higher than 8% at a thickness of 3.9 millimeters.

17. The glass sheet as in claim 16 wherein the color of the glass has dominant wavelengths in the range of 502 to 540 nanometers and an excitation purity of no higher than 3 percent.

3. A neutral gray colored glass composition having a base glass portion comprising:

4. The composition of claim 3 wherein the color of the glass has dominant wavelengths in the range of 485 to 560 nanometers and the corresponding complementary wavelengths and an excitation purity of no higher than 8% at a thickness of 3.9 millimeters.

5. The composition of claim 4 wherein the glass has an excitation purity of no higher than 3 percent.

6. The composition as in claim 3 wherein the FeO concentration is from 0.181 to 0.24 weight percent and the Se concentration is from 14 to 24 PPM.

7. A neutral gray colored glass composition having a base glass portion comprising:

8. The composition of claim 7 wherein the color of the glass has dominant wavelengths in the range of 502 to 580 nanometers and an excitation purity of no higher than 8% at a thickness of 3.9 millimeters.

9. The composition of claim 8 wherein the color of the glass has dominant wavelengths in the range of 502 to 540 nanometers and an excitation purity of no higher than 3 percent.

10. The composition as in claim 7 further including additional ultraviolet absorbing material.

11. The composition as in claim 10 wherein said ultraviolet absorbing material is an oxide of material selected from a group consisting essentially of cerium, vanadium, titanium and molybdenum and combinations thereof in an amount up to 2.0 wt. % of the glass composition.

12. The composition as in claim 11 wherein said ultraviolet absorbing material includes TiO₂ in an amount from 0.1 to 1.0 wt. %.

13. The composition as in claim 12 wherein said TiO₂ is in an amount from 0.2 to 0.5 wt. %.

18. A neutral gray colored glass composition having a base glass portion comprising:

19. The composition as in claim 18 wherein the Fe₂O₃ concentration is from 0.71 to 0.94 weight percent, the FeO concentration is from 0.181 to 0.24 weight percent, the CoO concentration is from 98 to 150 PPM and the Se concentration is from 14 to 24 PPM and the NiO concentration is at least 50 PPM and the glass is characterized by dominant wavelengths in the range of 502 to 580 nanometers and an excitation purity of no higher than 8% at a thickness of 3.9 millimeters.

20. The composition as in claim 18 further including an additional ultraviolet absorber which is an oxide of a material selected from a group consisting essentially of cerium, vanadium, titanium and molybdenum and combination thereof in an amount up to 2.0 wt. % of the glass composition.

21. The composition as in claim 20 wherein said ultraviolet absorber includes TiO₂ is in an amount from 0.1 to 1.0 wt. %.