Ultraviolet/infrared absorbent glass

Details Ultraviolet/infrared absorbent glass Ultraviolet/infrared absorbent glass

2001-02-20

2002-10-22

Group, Karl (Department: 1755)

Compositions: ceramic

Ceramic compositions

Glass compositions, compositions containing glass other than...

C501S070000, C501S071000

Reexamination Certificate

active

06468934

ABSTRACT:

FIELD ON THE INVENTION
The present invention relates to an ultraviolet/infared absorbent glass having a greenish color shade. Particularly, it relates to an ultraviolet/infared absorbent glass which has a high visible light transmittance and light greenish color shade so that it is useful for a window of a vehicle and a building.
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
Recently, a variety of glasses having an ultraviolet/infrared absorptivity and a greenish color shade to be used as a vehicle windshield has been proposed with the view of preventing degradation of luxurious interior materials and reducing cooling load of the vehicle.
For example, an ultraviolet/infrared absorbent glass having a greenish color shade disclosed in Japanese Patent H6-88812B consists of soda-lime glass including colorants consisting of 0.65 to 1.25 wt. % total iron oxide expressed as Fe
2
O
3
, 0.2 to 1.4 wt. % CeO
2
or 0.1 to 1.36 wt. % CeO
2
and 0.02 to 0.85 wt. % TiO
2
.
An ultraviolet/infrared absorbent glass having a relatively light greenish color shade disclosed in Japanese Patent H5-78147A consists of a base glass consisting of 68 to 72 wt. % SiO
2
,1.6 to 3.0 wt. % Al
2
O
3
, 8.5 to 11.0 wt. % CaO, 2.0 to 4.2 wt. % MgO, 12.0 to 16.0 wt. % Na
2
O and 0.5 to 3.0 wt. % K
2
O and colorants comprising 0.58 to 0.65 wt. % total iron oxide expressed as Fe
2
O
3
, 0.1 to 0.5 wt. % CeO
2
and 0.1 to 0.4 wt. % TiO
2
.
An ultraviolet/infrared absorbent glass disclosed in Japanese Patent H8-208266A and Japanese Patent H9-208254A has a relatively high visible light transmittance and a greenish color shade having high see-through visibility.
An ultraviolet/infrared absorbent glass disclosed in Japanese Patent H8-208266A consists of soda-lime-silica glass including colorants comprising 0.52 to 0.63 wt. % total iron oxide expressed as Fe
2
O
3
, 0.9 to 2 wt. % total CeO
2
and 0.2 to 0.6 wt. % TiO
2
wherein the divalent iron oxide expressed as Fe
2
O
3
is 28 to 38 wt. % of the total iron oxide expressed as Fe
2
O
3
.
An ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H9-208254A consists of a base glass comprising 67 to 75 wt. % SiO
2
, 0.05 to 3.0 wt. % Al
2
O
3
, 7.0 to 11.0 wt. % CaO, 2.0 to 4.2 wt. % MgO, 12.0 to 16.0 wt. % Na
2
O, 0.5 to 3.0 wt. % K
2
O, 0.05 to 0.30 wt. % SO
3
and 0 to 1 wt. % SnO
2
and colorants comprising 0.40 to 0.90 wt. % the total iron oxide expressed as Fe
2
O
3
, 1.0 to 2.5 wt. % CeO
2
, 0.1 to 1.0 wt. % TiO
2
, 0.0010 to 0.040 wt. % MnO, 0.0001 to 0.0009 wt. % CoO and 0.0001 to 0.0010 wt. % Cr
2
O
3
.
The colored film-coated glass can be prepared in an ion exchanging process in which ultra fine particles of an inorganic salt including silver or copper transmit into the glass base due to baking the glass applied with the inorganic salt including the silver or the copper on a surface thereof to cause transparent colloidal development, in a metallic film forming process in which a metallic film is flashed onto a glass base due to sputtering, or in a film forming process in which a film of metallic ultrafine particles is formed due to heating a glass base applied with the metallic salt compound dissolved in a solution of metal alcoxide.
Color development due to surface plasmon of metallic ultrafine particles is superior in heat resistance and light resistance and has been used in coloring of glass or earthenware. For example, according to J. Sol-Gel. Sci. Techn. 1,305-312 (1994), a colored film is obtained due to forming fine particles of gold by heating a glass base applied with a solution of alcoxide including chloroaurate and silane.
The aforementioned conventional ultraviolet/infrared absorbent glasses generally have problems as followings.
An ordinary ultraviolet/infrared absorbent glass having a greenish color shade including the glass disclosed in the Japanese Patent H6-88812B is possibly improved in the ultraviolet and infrared absorptivity so far as the visible light transmittance is within a permissive range (for example, more than 70% when the glass is employed for a front windshield of a vehicle.) and has a relatively deep greenish color shade having an excitation purity in a range of 2.4 to 3.3%. However, a glass having a light greenish color shade is sometimes preferred for a window of a vehicle and for a window of a building.
A glass having a possibly high ultraviolet and infrared absorptivity with a high visible light transmittance can be often required for a window of a building.
A glass plate can be employed for a window of a vehicle not only alone but with a variety of coatings applied onto a surface thereof. When the glass has a coating on the surface thereof, the coating reduces the visible light transmittance of the glass plate. Therefore, when the glass has a visible light transmittance having a value that is proximate to a lower limit of the aforementioned permissive range before being applied with a coating, even if the value is in the permissive range (for example, a value of slightly more than 70%), the value of the visible light transmittance easily becomes less than 70% after applying the coating. In this case, the glass can be hardly applied with a desired coating thereon.
The ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H5-78147A has a relatively lighter greenish color shade. The glass having a thickness of 5 mm has a visible light transmittance of 71% at most, which is not sufficiently high. Although the glass has a relatively lighter greenish color shade having an excitation purity of equal to or less than 5%, specifically, the value of the excitation purity is equal to or more than 3.2% and its greenish color shade can not be light enough.
The ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H8-208266A has a relatively high visible light transmittance and includes the total iron oxide expressed as Fe
2
O
3
in a range of 0.52 to 0.63 wt. % and the iron having two valences expressed as Fe
2
O
3
in a range of 28 to 38 wt. % of the total iron oxide. Although the glass provides a high solar rays absorptivity, i.e. a low solar energy transmittance, the visible light transmittance of the glass is in a range of 72.0 to 74.4% when the glass has a thickness of 3.5 mm, in a range of 71.4 to 72.9% when the glass has a thickness of 5 mm, which is not high enough in substantial.
Although the ultraviolet/infrared absorbent glass disclosed in the Japanese Patent H9-208254A has a relatively high see-through visibility and is provided with a high solar rays absorptivity, the visible light transmittance thereof is in a range 65.5 to 67.6% when the glass has a thickness of 5 mm, and it is not high enough in substantial. The excitation purity thereof is equal to or more than 2.9% and the greenish color shade thereof can not be light enough.
DISCLOSURE OF THE INVENTION
An ultraviolet/infrared absorbent glass of a first aspect of the present invention consists of a base glass comprising:
65 to 80 wt. % SiO
2
;
0 to 5wt. % Al
2
O
3
;
0 to 10 wt. % MgO;
5 to 15 wt. % CaO;
10 to 18 wt. % Na
2
O;
0 to 5 wt. % K
2
O;
5 to 15 wt. % a total amount of MgO and CaO;
10 to 20 wt. % a total amount of Na
2
O and K
2
O;
0.05 to 0.3 wt. % SO
3
; and
0 to 5 wt. % B
2
O
3
,
and a colorant including:
0.35 to 0.55 wt. % total iron oxide (T-Fe
2
O
3
) expressed as Fe
2
O
3
;
0.08 to 0.15 wt. % FeO;
0.8 to 1.5 wt. % CeO
2
; and
0 to 0.5 wt. % TiO
2
,
FeO expressed as Fe
2
O
3
being equal to or more than 20 wt. % and less than 27 wt. % of T-Fe
2
O
3
.
An ultraviolet/infrared absorbent glass plate of a second aspect of the present invention is composed of the ultraviolet/infrared absorbent glass of the first aspect wherein the visible light transmittance is equal to or more than 75% when measured by using the CIE illuminant A, the solar energy transmittance is equal to or less than 60%, the ultraviolet transmittance specified by ISO is equal to or less than 15%, the dominant wavelength is between 495 nm and 535 nm when measured by using the CIE illuminant C, and the excitation purity is equal to or less

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