Clear glass composition

Details Clear glass composition Clear glass composition

2002-01-28

2003-08-26

Group, Karl (Department: 1755)

Compositions: ceramic

Ceramic compositions

Glass compositions, compositions containing glass other than...

C501S070000

Reexamination Certificate

active

06610622

ABSTRACT:

BACKGROUND OF THE INVENTION
Glass that is fairly clear in color and highly transmissive to visible light (e.g., at least 75% transmissive, or even more preferably at least 80% transmissive) is sometimes desirable. One way of achieving such as glass is to use very pure base glass materials (e.g., substantially free of colorants such as iron). However, base materials with a high degree of purity are expensive and thus not always desirable and/or convenient. In other words, for example, the removal of iron from glass raw materials has certain practical and/or economical limits.
As can be appreciated from the above, glass raw materials (e.g., silica, soda ash, dolomite, and/or limestone) typically include certain impurities such as iron. The total amount of iron present is expressed herein in terms of Fe
2
O
3
in accordance with standard practice. However, typically, not all iron is in the from of Fe
2
O
3
. Instead, iron is usually present in both the ferrous state (Fe
2+
; expressed herein as FeO, even though all ferrous state iron in the glass may not be in the form of FeO) and the ferric state (Fe
3+
). Iron in the ferrous state (Fe
2
+; FeO) is a blue-green colorant, while iron in the ferric state (Fe
3+
) is a yellow-green colorant. The blue-green colorant of ferrous iron (Fe
2+
; FeO) is of particular concern when seeking to achieve a fairly clear or neutral colored glass, since as a strong colorant it introduces significant color into the glass. While iron in the ferric state (Fe
3+
) is also a colorant, it is of less concern when seeking to achieve a glass fairly clear in color since iron in the ferric state tends to be weaker as a colorant than its ferrous state counterpart.
In view of the above, it is apparent that there exists a need in the art for a new glass composition which enables a glass to have fairly clear color and/or high visible transmission, without having to resort to extremely pure (i.e., free of iron) glass raw materials.
SUMMARY OF THE INVENTION
An object of this invention is to provide a glass that has fairly clear color and/or high visible transmission.
Another object of this invention is to provide a glass having a visible transmission of at least 75% (more preferably at least 80%, and most preferably at least 85%), wherein in making the glass a batch therefor includes a base glass (e.g., soda lime silica glass) and in addition comprising (or consisting essentially of in certain embodiments), by weight percentage:
total iron (expressed as Fe
2
O
3
):
0.01 to 0.30%
erbium oxide (e.g., Er
2
O
3
):
0.01 to 0.30%
cerium oxide (e.g., CeO
2
):
0.005 to 0.30%. 
Optionally, other colorants such as neodymium oxide (e.g., Nd
2
O
3
) may also be provided in certain example embodiments. While cerium oxide is preferred in many embodiments, its presence is not a requirement. In other embodiments of this invention, the cerium oxide (e.g., CeO
2
) in the glass batch may be either replaced or supplemented by sodium nitrate (NaNO
3
) as an oxidizer.
Another object of this invention is to fulfill one or more of the above-listed objects and/or needs.
Certain example embodiments of the invention fulfill one or more of the above-listed objects and/or needs by providing a method of making glass, the method comprising:
providing a glass batch comprising:
Ingredient
wt. %
SiO
2
67-75%
Na
2
O
10-20%
CaO
 5-15%
MgO
0-5%
Al
2
O
3
0-5%
K
2
O
0-5%
total iron (expressed as Fe
2
O
3
)
0.01 to 0.30%
erbium oxide
0.01 to 0.30%
cerium oxide and/or a nitrate
0.005 to 2.0% 
neodymium oxide
  0 to 0.15%
melting the batch and forming a resulting glass that has visible transmission of at least 75%, a transmissive a* color value of −1.0 to +1.0, and a transmissive b* color value of −1.0 to +1.5.
Certain other example embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a glass comprising:
total iron (expressed as Fe
2
O
3
)
0.01 to 0.30%
erbium oxide
0.01 to 0.30%
cerium oxide
0.005 to 0.30%. 
Certain other example embodiments of this invention fulfill one or more of the above-listed objects and/or needs by providing a method of making glass, the method comprising providing a glass batch comprising:
total iron (expressed as Fe
2
O
3
):
0.01 to 0.30%
erbium oxide:
0.01 to 0.30%
cerium oxide and/or a nitrate:
0.005 to 2.0%, and
using the glass batch to make glass.
Certain other example embodiment of this invention fulfill one or more of the above-listed objects and/or needs by providing a glass comprising:
total iron (expressed as Fe
2
O
3
)
0.01 to 0.30%, and
erbium oxide
0.01 to 0.30%.
DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THIS INVENTION
Glasses according to different embodiments of this invention may be used, for example, in the automotive industry (e.g., windshields, backlites, side windows, etc.), in architectural applications, for patterned glass applications, solar cell applications, and/or in other suitable applications.
Certain glasses according to this invention utilize soda-lime-silica flat glass as their base composition/glass. In addition to base composition/glass, a unique colorant portion is provided in order to achieve a glass that is fairly clear in color and/or has a high visible transmission. An exemplary soda-lime-silica base glass according to certain embodiments of this invention, on a weight percentage basis, includes the following basic ingredients:
TABLE I
EXAMPLE BASE GLASS
Ingredient
Wt. %
SiO
2
67-75%
Na
2
O
10-20%
CaO
 5-15%
MgO
0-5%
Al
2
O
3
0-5%
K
2
O
0-5%
BaO
0-1%
Other minor ingredients, including various conventional refining aids, such as SO
3
, carbon, and the like may also be included in the base glass. In certain embodiments, for example, glass herein may be made from batch raw materials silica sand, soda ash, dolomite, limestone, with the use of salt cake (SO
3
) and/or Epsom salts (e.g., about a 1:1 combination of both) as refining agents. Preferably, soda-lime-silica based glasses herein include by weight from about 10-15% Na
2
O and from about 6-12% CaO. While a soda-lime-silica base glass set forth above is preferred in certain embodiments of this invention, this invention is not so limited. Thus, other base glasses (e.g., borosilicate glass) may instead be employed in alternative embodiments of this invention.
In addition to the base glass (e.g., see Table 1 above), in making glass according to the instant invention the glass batch includes materials (including colorants and/or oxidizers) which cause the resulting glass to be fairly neutral in color and/or have a high visible light transmission. These materials may either be present in the raw materials (e.g., small amounts of iron), or may be added to the base glass materials in the batch (e.g., cerium, erbium, etc.). In certain preferred embodiments, the resulting glass has visible transmission of at least 75%, more preferably at least 80%, and most preferably at least 85%.
In certain embodiments of this invention, in addition to the base glass, the glass batch includes materials as set forth in Table 2 below (in terms of weight percentage of the total glass composition):
TABLE 2
EXAMPLE GLASS BATCH OF FIRST EMBODIMENT
General
More
Most
Ingredient
(Wt. %)
Preferred
Preferred
total iron (expressed as
0.01-0.30%
0.02-0.20%
0.03-0.15%
Fe
2
O
3
):
erbium oxide (e.g., Er
2
O
3
):
0.01-0.30%
0.02-0.20%
0.03-0.13%
cerium oxide (e.g., CeO
2
):
0.005-0.30% 
0.01-0.18%
0.03-0.12%
The batch is melted and glass formed using the known float process. Optionally, in certain example embodiments of the invention, neodymium oxide (e.g., Nd
2
O
3
) may be added to the batch, as exemplified below in Table 3 according to a second example embodiment of this invention (the material listed in Table 3 are in addition to the base glass described above).
TABLE 3
EXAMPLE GLASS BATCH OF SECOND EMBODIMENT
General
More
Most
Ingredient
(Wt. %)
Preferred
Preferred
total iron (expressed as
0.01-0.30%
0.02-0.20%
0.03-0.15%
Fe
2
O
3
):
erbium oxide (e.g.,
0.01-0.30%
0.02-0.20

Affiliated with

Also associated with

Rating

Clear 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 Clear glass composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clear glass composition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3077786