Compositions: ceramic – Ceramic compositions – Glass compositions – compositions containing glass other than...
Reexamination Certificate
1995-09-15
2001-08-14
Group, Karl (Department: 1755)
Compositions: ceramic
Ceramic compositions
Glass compositions, compositions containing glass other than...
C501S070000
Reexamination Certificate
active
06274523
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention involves a neutral gray colored glass that has a luminous transmittance that makes it highly desirable for use as privacy glazing in vehicles, e.g. in the rear portions of vans. In particular, the glass of the present invention has a luminous transmittance range of up to 45 percent. The desired color and performance is attained by using iron, cobalt, selenium and/or nickel as colorants. In addition, the glass of the present invention generally exhibits lower infrared and total solar energy transmittance than typical green glasses used in automotive applications to reduce heat gain in the interior of the enclosure. The glass is also compatible with flat glass manufacturing methods.
Various heat-absorbing glass substrates are known in the art. The primary colorant in typical green tinted automotive glasses is iron, which is usually present in both the Fe
2
O
3
and FeO forms. As is conventional, the total amount of iron present in a glass is expressed herein as Fe
2
O
3
, regardless of the form actually present. Typical green tinted automotive glass has about 0.5 percent by weight total iron with the ratio of FeO to total iron being about 0.25.
Some glasses, e.g. U.S. Reissue Pat. No. 25,312 to Duncan et al. and U.S. Pat. No. 4,339,541 to Dela Ruye, produce a gray color in the glass by including nickel oxide, cobalt oxide and selenium as colorants. However, inclusion of nickel-containing materials must be carefully controlled because the presence of nickel during the melting process sometimes leads to the formation of nickel sulfide stones in the glass. Additional potential problems faced when using nickel include haze formation on the glass surface due to reduction of the nickel in the tin bath and change in the glass color when it is heat treated.
To avoid this problem, nickel-free colored glasses containing iron oxide, cobalt oxide, and selenium were developed, as disclosed in U.S. Pat. No. 3,296,004 to Duncan et al., U.S. Pat. No. 3,723,142 to Kato et al. and British Patent Specification 1,331,492 to Bamford. In U.S. Pat. No. 4,104,076 to Pons, instead of nickel, Cr
2
O
3
or UO
2
are used in combination with iron oxide, cobalt oxide, and selenium to produce gray glass. More recent nickel-free gray glasses are disclosed in U.S. Pat. No. 5,023,210 to Krumwiede et al. and U.S. Pat. No. 5,278,108 to Cheng et al. and EP 536 049 to Alvarez-Casariego, et al., which use iron oxide, cobalt oxide and selenium, as colorants. Krumwiede et al. and Alvarez-Casariego et al. further disclose that chromic oxide may be used as an additional colorant.
Many of the commercially available gray glasses are too dark to be used in the forward vision area of a vehicle. In addition, the glasses may also be too dark to allow safety lighting mounted in the interior of the vehicle from being seen from the exterior of the vehicle. It would be desirable to have a neutral gray glass that provides a dark gray color for use in privacy areas of a vehicle while allowing adequate safety lighting illumination and have a consistent color and further that is compatible with commercial flat glass manufacturing techniques.
SUMMARY OF THE INVENTION
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 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 Fe
2
O
3
(total iron), no greater than 0.30 wt. % FeO; 60 to 180 PPM CoO and 5 to 30 PPM Se. In one embodiment, the glass composition includes 0.75 to 0.86 wt% Fe
2
O
3
; 0.18 to 0.25 wt. % FeO; 108 to 144 PPM CoO and 13 to 24 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 45% at a thickness of 3.9 millimeters may be attained by using as colorants: 0.35 to 1.1 wt. % of the total glass Fe
2
O
3
(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. In one embodiment, the glass composition includes 0.71 to 0.94 wt. % Fe
2
O
3
, 0.181 to 0.24 wt. % FeO, 98 to 150 PPM CoO, 14 to 24 PPM Se, and a minimum of 50 PPM NiO.
The dominant wavelength of the glasses in the present invention may vary somewhat in accordance with particular color preferences. In the present invention, it is preferred that the glass be a neutral gray color characterized by dominant wavelengths in the range of 480 to 580 nanometers, preferably 485 to 560 nanometers, with an excitation purity of no higher than 8%, preferably no higher than 3%.
REFERENCES:
patent: Re. 25312 (1963-01-01), Duncan et al.
patent: 1957279 (1934-05-01), Linke
patent: 2524719 (1950-10-01), Tillyer
patent: 2688565 (1954-09-01), Raymond
patent: 2860059 (1958-11-01), Molter et al.
patent: 2892726 (1959-06-01), Smith et al.
patent: 3294556 (1966-12-01), Harrington
patent: 3294561 (1966-12-01), Duncan et al.
patent: 3296004 (1967-01-01), Duncan
patent: 3300323 (1967-01-01), Plumat et al.
patent: 3411934 (1968-11-01), Englehart et al.
patent: 3498806 (1970-03-01), Hammer et al.
patent: 3628932 (1971-12-01), Inoue et al.
patent: 3660061 (1972-05-01), Donley et al.
patent: 3723142 (1973-03-01), Kato et al.
patent: 3967040 (1976-06-01), Plumat et al.
patent: 4101705 (1978-07-01), Fischer et al.
patent: 4104076 (1978-08-01), Pons
patent: 4129434 (1978-12-01), Plumat et al.
patent: 4190452 (1980-02-01), Fischer et al.
patent: 4294881 (1981-10-01), Meyer et al.
patent: 4308319 (1981-12-01), Michelotti et al.
patent: 4336303 (1982-06-01), Rittler
patent: 4339541 (1982-07-01), Dela Ruye
patent: 4521454 (1985-06-01), Kandachi et al.
patent: 4617206 (1986-10-01), Haisma et al.
patent: 4719126 (1988-01-01), Henery
patent: 4719127 (1988-01-01), Greenberg
patent: 4728353 (1988-03-01), Thomas et al.
patent: 4792536 (1988-12-01), Pecoraro et al.
patent: 4798616 (1989-01-01), Knavish et al.
patent: 4866010 (1989-09-01), Boulos et al.
patent: 4873206 (1989-10-01), Jones
patent: 4971843 (1990-11-01), Michelotti et al.
patent: 5023210 (1991-06-01), Krumwiede et al.
patent: 5030593 (1991-07-01), Heitoff
patent: 5070048 (1991-12-01), Boulos et al.
patent: 5264400 (1993-11-01), Nakaguchi et al.
patent: 5278108 (1994-01-01), Cheng et al.
patent: 5308805 (1994-05-01), Baker et al.
patent: 5318931 (1994-06-01), Nakaguchi et al.
patent: 5346867 (1994-09-01), Jones et al.
patent: 5364820 (1994-11-01), Morimoto et al.
patent: 5393593 (1995-02-01), Gulotta et al.
patent: 5411922 (1995-05-01), Jones
patent: 5478783 (1995-12-01), Hruby et al.
patent: 5582455 (1996-12-01), Casariego et al.
patent: 596334 (1990-04-01), None
patent: 735187 (1966-05-01), None
patent: 0 297 404 (1989-01-01), None
patent: 0 349 909 (1990-01-01), None
patent: 0 452 207 (1991-04-01), None
patent: 0 482 535 (1992-04-01), None
patent: 0 536 049 (1993-04-01), None
patent: 2082647 (1971-12-01), None
patent: 2270215 (1975-04-01), None
patent: 2 331 527 (1975-11-01), None
patent: 2690437 (1993-10-01), None
patent: 1331492 (1973-09-01), None
patent: 1512704 (1978-06-01), None
patent: 2071082 (1981-09-01), None
patent: 56-41579 (1981-09-01), None
patent: 91/07356 (1991-05-01), None
patent: 91/11402 (1991-08-01), None
Glass Colors, V, Examples of the Composition of Colored Glasses, Kocik et al., Fachberichte, Sprechsaal, vol. 121, No. 1, (1988), pp. 42-44 (No month).
JP-57 106 537, Entitled “Bronze Color Plate Glass”, Patent Abstracts of Japan, vol. 6, No. 197, Oct. 1982.
“The Behavior of Selenium and Its Compounds During the Melting of a Vitrifiable Batch”, by S.A. Glaverbel, Sep. 1967.
“Iron-selenium black glass”, A. Paul, Department of Glass Technology, University of Sheffield (No Date).
“Oxidation-Red
Haskins David R.
Krumwiede John F.
Longobardo Anthony V.
Shelestak Larry J.
Group Karl
PPG Industris Ohio, Inc.
Siminerio Andrew C.
Stachel Kenneth J.
LandOfFree
Gray glass composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gray glass composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gray glass composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2440754