Ultraviolet and infrared radiation absorbing glass

Details Ultraviolet and infrared radiation absorbing glass Ultraviolet and infrared radiation absorbing glass

2000-01-03

2001-12-04

Sample, David R. (Department: 1755)

Compositions: ceramic

Ceramic compositions

Glass compositions, compositions containing glass other than...

C501S065000, C501S066000, C501S071000

Reexamination Certificate

active

06326324

ABSTRACT:

TECHNICAL FIELD
The present invention relates to an ultraviolet and infrared radiation absorbing glass having a bronze or neutral gray tint.
TECHNICAL BACKGROUND
In order to meet the demand for protection of interior trim of automobiles against deterioration, which has been increasing with the recent trend to luxury of the interior trim, and to reduce the load of air conditioning, a glass having ultraviolet and infrared radiation absorbing power has recently been proposed as an automotive window glass.
For example, a green tinted glass containing a relatively large amount of Fe
2
O
3
and having enhanced heat radiation and ultraviolet radiation absorbing power has been developed for automotive use.
In glasses having a bronze or brown tint, the ultraviolet radiation absorbing power thereof is enhanced by using CeO
2
and TiO
2
at a lower Fe
2
O
3
content than the green tinted glass. For example, the heat radiation absorbing glass having a bronze tint disclosed in JP-A-6-40741 (the term “JP-A” as use herein means an “unexamined published Japanese patent, application”) comprises, in % by weight, basic glass components comprising 68 to 74% SiO
2
, 0.1 to 3% Al
2
O
3
, 2 to 4.5% MgO, 8 to 11% CaO, 11.5 to 16% Na
2
O, 0.5 to 3.0% K
2
O, and 0.1 to 0.4% SO
3
, provided that the sum of SiO
2
and Al
2
O
3
is 68 to 74%, the sum of CaO and MgO is 11 to 15%, and the sum of Na
2
O and K
2
O is 12 to 17%, and coloring components comprising 0.13 to 0.55% total iron oxide in terms of Fe
2
O
3
, 0.2 to 0.6% CeO
2
, and 0.15 to 0.45% TiO
2
, and further comprises 0.3 to 14 ppm CoO and 5 to 20 ppm Se. This glass has a reduction rate (Fe
2+
/Fe
3+
) of 17 to 55%.
The ultraviolet radiation absorbing colored glass disclosed in JP-A-6-345482 is a brown tinted glass which comprises, in % by weight, 65 to 75% SiO
2
, 0.1 to 5% Al
2
O
3
, 1 to 6% MgO, 5 to 15% CaO, 10 to 18% Na
2
O, 0 to 5% K
2
O, 0.05 to 1.0SO
3
, 0.2 to 1.5% CeO
2
, 0 to 1.0% TiO
2
, 0 to 0.0015% CoO, 0.0002 to 0.0012% Se, and 0.2 to 0.4% Fe
2
O
3
, wherein 3 to 15% of the total iron oxide in terms of Fe
2
O
3
is FeO.
The ultraviolet radiation absorbing colored glass disclosed in JP-A-6-345483 is a glass which comprises, in % by weight, 65 to 75% SiO
2
, 0.1 to 5% Al
2
O
3
, 1 to 6% MgO, 5 to 15% CaO, 10 to 18% Na
2
O, 0 to 5% K
2
O, 0.05 to 1.0% SO
3
, 0.4 to 1.0% CeO
2
, 0 to 1.0% TiO
2
, 0.0018 to 0.0030% CoO, 0.0001 to 0.0010% Se, and 0.1 to 0.3% Fe
2
O
3
, wherein 3 to 20% of the total iron oxide in terms of Fe
2
O
3
is FeO.
Furthermore, the gray glass composition disclosed in JF-A-8-48540 is a colored glass composition having a dull gray tint which comprises, in % by weight, 66 to 75% SiO
2
, 0 to 5% Al
2
O
3
, 0 to 5% MgO, 5 to 15% CaO, 10 to 20% Na
2
O, 0 to 5% K
2
O, 0.0003 to 0.0050% CoO, 0.0001 to 0.0015% Se, and 0.30 to 0.70% Fe
2
O
3
(total iron oxide), with the FeO content being up to 0.21%, and which may further contain up to 2.0% CeO
2
, V
2
O
5
, TiO
2
, and MoO
3
.
The above-described conventional ultraviolet and infrared radiation absorbing glasses have an ultraviolet radiation absorbing power imparted by Fe
2
O
3
CeO
2
, and TiO
2
, and by interactions among them. However, in the glasses having a bronze or neutral gray tint obtained by using the coloration of Se, the Fe
2
O
3
content must be reduced to a relatively low level in order to maintain the pink coloration of Se. Consequently, it has been difficult to achieve both a bronze or neutral gray tint and high ultraviolet radiation absorbing power.
That is, there has been the following problems. When the TiO
2
content is increased, the glass tends to be yellowish. Even when the CeO
2
content is increased, the coloration of Se is sometimes insufficient depending on the oxidation and reduction state of the glass, so that the ultraviolet radiation absorbing power is not effectively increased.
This kind of glasses further have a drawback that an increase in the proportion of FeO in total iron oxide tends to result in the above-described problems concerning color tint. In the case of ordinary glasses having a bronze or neutral gray tint and not having high ultraviolet radiation absorbing power, an increase in FeO proportion may impair the infrared radiation absorbing power thereof.
The present invention has been made in the light of the above-described problems associated with the conventional techniques.
An object of the present invention is to provide an ultraviolet and infrared radiation absorbing glass having a bronze or neutral gray tint and having especially high ultraviolet radiation absorbing power and satisfactory infrared radiation absorbing power.
DISCLOSURE OF THE INVENTION
The present invention provides an ultraviolet and infrared radiation absorbing glass comprising, in % by weight:
basic glass components comprising
65 to 80% SiO
2
,
0 to 5% B
2
O
3
,
0 to 5% Al2O
3
,
0 to 10% MgO,
5 to 15% CaO,
10 to 18% Na
2
O, and
0 to 5% K
2
O,
provided that the sum of MgO and CaO is 5 to 15% and the sum of Na
2
O and K
2
O is 10 to 20%;
coloring components comprising
0.20 to 0.30% total iron oxide (T-Fe
2
O
3
) in terms of Fe
2
O
3
,
0.65 to 1.1% CeO
2
,
0.35 to 1.1% TiO
2
,
0.001 to 0.005% CoO, and
0.0003 to 0.0015% Se; and
an additional component comprising
0.02 to 0.30% SO
3
,
wherein 20.5 to 25% of said T-Fe
2
O
3
is FeO in terms of Fe
2
O
3
.
PREFERRED EMBODIMENTS OF THE INVENTION
The ultraviolet and infrared radiation absorbing glass described above preferably contains 0.0005 to 0.005% by weight NiO.
The ultraviolet and infrared radiation absorbing glass preferably contains 0.20 to 0.90% by weight La
2
O
3
.
The ultraviolet and infrared radiation absorbing glass of the present invention preferably has such optical characteristics that the visible light transmission as measured with the CIE standard illuminant A of 70% or more and the total solar energy transmission as measured in a wavelength region of from 300 to 2,100 nm is less than 72%, when the thickness thereof is from 3.25 to 6.25 mm.
Furthermore, the ultraviolet and infrared radiation absorbing glass of the present invention preferably has such optical characteristics that the dominant wavelength thereof as measured with the CIE standard illuminant C is 572 to 580 nm and the total sunlight ultraviolet transmission defined in ISO9050 as measured in a wavelength region of from 297.5 to 377.5 nm is less than 12%, when the glass has a thickness of 3.25 to 6.25 mm.
The reasons for limitations of the composition of the ultraviolet and infrared radiation absorbing glass according to the present invention are explained below. Hereinafter, all percents used for component amounts are by weight. The composition of the glass is based on a glass composition suitable for forming by a float process.
SiO
2
is a main component forming a skeleton of glass. If the SiO
2
content is less than 65%, the glass has poor durability. If the SiO2 content exceeds 80%, the glass is difficult to melt.
Although B
2
O
3
, is a component generally used for improving glass durability or as a melting aid, it also functions to enhance ultraviolet absorption. If the B
2
O
3
content exceeds 5%, not only the decrease of transmission in the ultraviolet region extends to the visible region, often resulting in a yellowish tint, but also troubles arise in glass forming due to vaporization of B
2
O
3
, etc. Accordingly, the upper limit of the B
2
O
3
content should be 5%.
Al203 serves to improve glass durability. If the Al
2
O
3
content exceeds 5%, the glass is difficult to melt. From the standpoint of obtaining a glass having moderately improved durability while preventing the glass from having an elevated melting temperature, the preferred range of Al
2
O
3
content is from 0.1 to 2%.
MgO and CaO both are used for improving glass durability and for regulating a liquidus temperature and viscosity of the glass during forming. If the MgO content exceeds 10%, the liquidus temperature rises. If the CaO content is less than 5% or higher than 15%, the liquidus temperature rises. If the total content of MgO and CaO is less t

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