WO2008038779A1 - Glass composition and glass article using the same - Google Patents

Abstract

Disclosed is a glass composition having a reduced sodium content and having a UV transmittance, a thermal expansion coefficient, a glass transition temperature and a softening point in levels suitable for use as an electrical glass. Specifically disclosed is a glass composition which comprises SiO2, Na2O, K2O, CaO and SO3 as essential ingredients, which is characteristic in the contents of Na2O and K2O, which contains SO3 in an amount of 0.05 to 0.5 mass% inclusive and iron oxides in the total amount of 0.05 to 0.35 mass% inclusive in terms of Fe2O3, and which contains substantially no antimony oxide.

Description

 Specification

 GLASS COMPOSITION AND GLASS ARTICLE USING THE SAME

 Technical field

 [0001] The present invention relates to a glass composition and a glass article for illumination using the same. Specifically, the present invention relates to a glass composition suitable for glass for fluorescent lamps and a glass article for illumination using the same as a glass article.

 Background art

 As a glass for illumination such as a fluorescent lamp, a soda-lime-based glass composition containing 10 to 20% by mass of sodium oxide has been used. Mercury is sealed in the tube of the fluorescent lamp. From time to time, sodium may elute from lighting glass made of soda-lime glass composition.

 [0003] The phenomenon in which the end of a fluorescent lamp is blackened and its life is shortened occurs when the eluted sodium is combined with the above-mentioned mercury and adheres to the inside of the fluorescent lamp. For this reason, it has been proposed to reduce the sodium content in the soda-lime glass composition.

 For example, in the “glass composition for lamp” disclosed in JP-A-11-224649, the total of Na 0, K 2 and Li 2 O is 13% or less.

 [0005] In addition, in the “glass composition suitable for use in fluorescent lamps” disclosed in Japanese Patent Publication No. 11 509514 (W097 / 43223), sodium is reduced in a small amount (Na O <0.1 by weight%). Restricted.

 [0006] Further, in the “illuminating glass composition” disclosed in Japanese Patent Application Laid-Open No. 2003 073142, sodium is substantially contained!

[0007] In a glass composition for a fluorescent lamp, it is not preferable to cause solarization that lowers the transmittance of the glass when irradiated with ultraviolet rays. Some of the publications referring to solarization in glass compositions for fluorescent lamps are described below.

 * Japanese Patent Laid-Open No. 06-092677

 * JP 2001-243914

* JP 2002-137935 * JP 2003-171141 A

[0008] Generally, soda-lime glass compositions inevitably contain iron due to industrial raw materials. Iron oxide contained in the glass acts as a colorant and exists in the form of Fe ²⁺ and Fe ³⁺ . Fe ²⁺ has an absorption peak near the wavelength l lOOnm, and Fe ³⁺ has an absorption near the wavelength 400nm.

[0009] In a glass composition for a fluorescent lamp, transmittance is an important characteristic. Therefore, not only the content of iron oxide contained in the glass but also the ratio of Fe ²⁺ to Fe ³⁺ is important for the transmittance.

 [0010] Some of the publications relating to glass compositions for lighting are described below.

 'Publication No. 09-012332

 'JP-A-10-152340

 * JP 2000-290038

 * JP 2000-315477

 * JP 2005-314169

[0011] In the glass composition disclosed in JP-A-11-224649, the inclusion of Sb 2 O or CeO is permitted, and BaO is contained indispensable. There is no description about SO.

 The glass composition disclosed in JP-T-11 509514 not only restricts sodium, but also allows the inclusion of CeO and essentially contains BaO.

 The glass composition disclosed in Japanese Patent Application Laid-Open No. 2003-073142 contains substantially no sodium, allows the inclusion of Sb 2 O and CeO, and contains BaO as an essential component. There is no description about SO.

 [0012] In the glass composition disclosed in Japanese Patent Application Laid-Open No. 06-092677, Sb 2 O is an essential component, CeO is allowed to be contained, and BaO is essentially contained. There is no description about SO. In the glass composition disclosed in JP-A-2001-243914, CeO is an essential component, Sb 2 O is allowed to be contained, and BaO is essentially contained.

 In the glass composition disclosed in JP-A-2002-137935, CeO is an essential component, Sb 2 O is allowed to be contained, and BaO is essentially contained.

The glass composition disclosed in JP-A-2003-171141 has SbO as an essential component. , Li O is contained in an amount of 0.5 mass% or more.

[0013] The glass composition disclosed in Japanese Patent Application Laid-Open No. 09-013232 permits the inclusion of Sb 2 O and CeO as well as the description about Fe.

 In the glass composition disclosed in JP-A-10-152340, SO or so-called iron ratio is used.

(For example, FeO / total iron oxide) The description of SbO is allowed, and BaO is essential.

 In the glass composition disclosed in Japanese Patent Application Laid-Open No. 2000-290038, the content of PO is allowed without any description regarding SO or so-called iron ratio (for example, FeO / total iron oxide). In the glass composition disclosed in Japanese Patent Application Laid-Open No. 2000-315477, Sb 2 O is an essential component, P 2 O is allowed to be contained, and BaO is essential.

 In the glass composition disclosed in Japanese Patent Application Laid-Open No. 2005-314169, there is no description about SO and so-called iron ratio (for example, FeO / total iron oxide). Sb O and CeO are allowed to be contained, and BaO is optionally contained. .

 Disclosure of the invention

 [0014] The present invention provides a glass composition that can have an ultraviolet transmittance, a thermal expansion coefficient, a glass transition point, and a softening point, which is preferable as a glass for lighting while suppressing the sodium content in the glass composition. The purpose is to provide. Furthermore, the provision of a glass article using this glass composition will be provided.

 [0015] The present invention is a glass yarn composition comprising SiO, Na 0, K 0, CaO and SO as essential components, and is characterized by the content of Na 2 O and KO, particularly SO 0.05% or more and 0.5% or less, and the total iron oxide in terms of Fe 2 O is 0.05% by mass or more and 0.35% by mass or less, and contains substantially no antimony oxide. It is a composition.

[0016] That is, the present invention is expressed in mass%,

 SiO 65% or more, 75% or less,

 Al O 0% or more, less than 5%,

 B O 0% or more, 5% or less,

 Na O> 3%, <12%,

KO 2% or more, 15% or less, Li O 0% or more, less than 5%,

 Na O + K O + Li O 6% or more, 20% or less,

 MgO 0% or more, 10% or less,

 CaO over 5%, 15% or less,

 BaO 0% or more, less than 4%,

 SrO 0% or more, 10% or less,

 ZnO 0% or more, 10% or less,

 MgO + CaO + SrO + BaO + ZnO over 5%, 19% or less,

 SrO + BaO + ZnO 0% or more, 10% or less,

 TiO 0% or more, 0.5% or less,

 ZrO 0% or more, 2.5% or less,

 CeO 0% or more, 0.5% or less,

 SO 0.05% or more, 0.5% or less, and

 Total iron oxide converted to Fe O 0.05% or more, 0.35% or less,

 Comprising

 It is a glass composition characterized by containing substantially no antimony oxide.

 [0017] The present invention suppresses the sodium content in the glass composition. Constructing a fluorescent lamp using this glass composition is effective in preventing blackening of the fluorescent lamp because it prevents elution of sodium.

 [0018] The glass composition of the present invention is preferred as a glass for lighting because solarization is suppressed and it has low ultraviolet light transmittance.

 Furthermore, the present invention is a glass composition having a thermal expansion coefficient, a glass transition point, and a softening point, which is preferable as a lighting glass, and has excellent moldability.

 Brief Description of Drawings

 FIG. 1 is a schematic cross-sectional view of a surface lighting device 1.

 FIG. 2 is a schematic sectional view of the surface illumination device 2.

 FIG. 3 is a partially enlarged perspective view of the surface illumination device 3.

BEST MODE FOR CARRYING OUT THE INVENTION [0020] [Glass composition]

 Below, each component in a glass composition is demonstrated. In addition, each content rate is a mass% display, and the ratio of a component is also a mass ratio.

[0021] (SiO 2)

 SiO is a main component forming a glass skeleton. If the SiO content is less than 65%, the durability of the glass decreases. If it exceeds 75%, it becomes difficult to melt the glass, and the softening point of the glass becomes too high. The lower limit of the SiO content is 65% or more, preferably 67% or more, and more preferably 68% or more. The upper limit of the content of SiO is 75% or less, preferably 73% or less, and more preferably 72% or less. The SiO range is selected from any combination of these upper and lower limits.

[0022] (Al O)

 Al O is an optional component that improves the durability of glass. If the content of Al O exceeds 5%, melting of the glass becomes difficult and the softening point of the glass becomes too high. The lower limit of the content of Al 2 O 3 is 0% or more, more than 0% is preferable, 0.1% or more is more preferable, and 0.5% or more is more preferable. The upper limit of the Al 2 O content is less than 5%, preferably less than 2%, more preferably less than 1.5%, and most preferably less than 1%. The range of Al 2 O is selected from any combination of these upper and lower limits.

[0023] (B O)

 B 2 O is an optional component used to improve the durability of the glass or as a melting aid. Exceeding B 2 O force will cause inconvenience during molding due to volatilization of B 2 O, etc.

The upper limit is 5%. B O also erodes bricks and shortens kiln life.

, It is desirable not to contain substantially.

[0024] (Na O)

Na 2 O is used as a glass melting accelerator. When Na 2 O is 3% or less, the melting promotion effect is poor. When Na 2 O is 12% or more, the durability of the glass is lowered, and sodium elution, which is a problem particularly in glass for fluorescent lamps, increases, which is not preferable. The lower limit of the Na 2 O content is more than 3%, preferably 4% or more, more preferably 6% or more, and further preferably 7% or more. The upper limit of Na O content is less than 12% and not more than 9% Is preferred. The range of Na 2 O is selected from any combination of these upper and lower limits.

[0025] (K O)

 K 2 O is an essential component used as a glass melting accelerator in the present invention, like Na 2 O. If K 2 O is less than 2%, the effect of promoting melting is poor. Since K 2 O is more expensive than Na 2 O, it is not preferable to exceed 15%. The lower limit of the content of K 2 O is 2% or more, preferably 4% or more, and more preferably 6% or more. The upper limit of the content of K 2 O is 15% or less, preferably less than 10% is preferably 9% or less, more preferably 8% or less. The range of K O is selected from any combination of these upper and lower limits.

[0026] (Li O)

 Li 2 O is not an essential component, but it is used as a glass melting accelerator in the same way as Na 2 O and K 2 O. Further, it is an effective component for adjusting the thermal expansion coefficient and low temperature viscosity, and it is preferable to contain even a trace amount. On the other hand, Li O is more expensive than Na 2 O, so 5% or more is not preferable. The lower limit of the Li 2 O content is 0% or more, preferably more than 0%, more preferably 0.05% or more, and most preferably 0.1% or more. The upper limit of the Li O content is less than 5%, preferably 3% or less 1. More preferably 5% or less, more preferably 1% or less, and even more preferably less than 1% Even more preferred is less than 0.5%. Most preferred is less than 0.35%. The range of Li 2 O is selected from any combination of these upper and lower limits.

 [0027] (Na O + K O + Li O)

 If the total force S of (Na 2 O + K 2 O + Li 2 O) is less than 6%, the durability of the glass decreases if it exceeds 20%, the effect of promoting melting. The lower limit of the total of (Na 2 O + K 2 O + Li 2 O) is 6% or more, preferably 10% or more. The upper limit of the total of (Na 2 O + K 2 O + Li 2 O) is 20% or less, preferably 19.5% or less, and more preferably 17.5% or less. The range of (Na 2 O + K 0 + Li 2 O) is selected from any combination of these upper and lower limits.

 [0028] (Na O / K O)

In the present invention, the ratio of Na 2 O to KO (Na 2 O / K Ο) is important. Na O and KO A large ratio is not preferable because sodium elution increases. A small ratio of Na 2 O to KO is not preferable because expensive KO increases.

 In the present invention, the lower limit of Na 2 O / K 2 O is preferably more than 0.2, more preferably 0.6 or more, and more preferably 0.9 or more. The upper limit of Na 2 O / K 2 O is preferably less than 3 and is preferably S, more preferably 1.5 or less, and even more preferably 1.1 or less. The range of Na O / K O is selected from any combination of these upper and lower limits.

[0029] (MgO)

 MgO is not an essential component, but is used to improve the durability of the glass and adjust the devitrification temperature and viscosity during molding. When MgO exceeds 10%, the devitrification temperature rises. The lower limit of the content of MgO is 0% or more, more than 0% is preferable, 2% or more is more preferable, and more preferably more than 4%. The upper limit of the content of MgO is 10% or less, preferably 6% or less, and more preferably 5% or less. The range of MgO is selected from any combination of these upper and lower limits.

[0030] (CaO)

 CaO, like MgO, is an essential component used to improve the durability of the glass and adjust the devitrification temperature and viscosity during molding. If CaO is 5% or less, the meltability deteriorates. If it exceeds 15%, the devitrification temperature rises. The lower limit of the CaO content is more than 5%, more preferably 5.5% or more, more preferably 6% or more, and even more preferably more than 6%. The upper limit of the CaO content is 15% or less, preferably 12% or less, more preferably 10% or less, and still more preferably 8% or less. The range of CaO is selected from any combination of these upper and lower limits.

[0031] (SrO)

 SrO is not an essential component, but it is used to adjust the devitrification temperature and viscosity when forming glass, just like MgO and CaO. The SrO content is set to 10% or less, but when the glass composition is constituted without containing SrO as much as possible, the content is preferably less than 4%, and more preferably less than 1%.

On the other hand, the present invention can be realized even if 4% or more of SrO is contained. In that case, the lower limit of Sr 2 O is preferably 4% or more, more preferably more than 4%. The upper limit of SrO is 7 % Or less is preferred. 6% or less is more preferred. If 4% or more of SrO is included, formability is improved.

[0032] (BaO)

 BaO is not an essential component, but it is used to adjust the devitrification temperature and viscosity when forming glass, just like MgO and CaO. When the content of BaO is large, the density of the glass increases, which is disadvantageous in terms of weight reduction when used as a glass article. Therefore, the upper limit of BaO is less than 4%, more preferably less than 1%. . The glass composition of the present invention is determined by the force to be established without substantially containing BaO.

[0033] (ZnO)

 ZnO is not an essential component, but it is used to adjust the devitrification temperature and viscosity when forming glass, just like MgO and CaO. ZnO tends to be non-homogeneous because it tends to volatilize. When glass is formed by the float process, it tends to agglomerate in the low temperature part after volatilization in the float bath. Aggregation of ZnO may cause surface defects of the glass. Therefore, the content is not more than 10%, preferably not more than 6%, more preferably not more than 5%. I like that!

 [0034] (MgO + CaO + SrO + BaO + ZnO)

 If the total of (MgO + CaO + SrO + BaO + ZnO) is 5% or less, the durability of the glass will decrease. On the other hand, if it exceeds 19%, the devitrification temperature rises or the coefficient of thermal expansion becomes too large. The lower limit of the content of (MgO + CaO + SrO + BaO + ZnO) is more than 5%, preferably 10% or more. The upper limit of the content of (MgO + CaO + SrO + BaO + ZnO) is 19% or less, preferably 16% or less, and more preferably less than 15%. The range of (MgO + CaO + SrO + BaO + ZnO) is selected from any combination of these upper and lower limits.

 [0035] (SrO + BaO + ZnO)

If the amount of (SrO + BaO + ZnO) increases, the expansion coefficient becomes too large, so it is not preferable that the total exceeds 10%. The lower limit of the content of (SrO + BaO + ZnO) is 0% or more. The upper limit of the content of (SrO + BaO + ZnO) is 10% or less, preferably 8% or less, more preferably 6% or less, and even more preferably 5% or less. (SrO + BaO + ZnO) The range is selected from any combination of these upper and lower limits.

[0036] (TiO)

 TiO is not an essential component, but can be added as long as the object of the present invention is not impaired. If the amount of TiO becomes too large, the glass tends to become yellowish. Therefore, the upper limit of the content of TiO is 0.5% or less, preferably less than 0.1%, and less than 0.05%. More preferred. On the other hand, the lower limit of the content of TiO is 0% or more. The range of TiO is selected from any combination of these upper and lower limits.

[0037] (ZrO)

 ZrO is not an essential component, but it is an effective component for improving the durability of the glass and adjusting the devitrification temperature during molding. 2. If it exceeds 5%, it tends to devitrify. ZrO is an expensive raw material and is preferably less than 0.5%. The lower limit of the ZrO content is 0% or more. The upper limit of the content of ZrO is 2.5% or less, preferably less than 0.5%, more preferably less than 0.2%. The ZrO range is selected from any combination of these upper and lower limits.

[0038] (CeO)

 CeO has an action of absorbing ultraviolet rays in glass and is an effective component for suppressing ultraviolet transmittance. The glass composition of the present invention may contain 0.5% or less. However, since solarization occurs due to the irradiation of ultraviolet rays and the visible light transmittance of the glass decreases, it is more preferable that the glass is not substantially contained.

[0039] (SO)

 SO is a component that promotes clarification of glass. If it is less than 0.05%, the clarification effect is insufficient with the normal melting method, and the desirable range is 0.1% or more. On the other hand, if it exceeds 0.5%, SO produced by the decomposition will remain in the glass as bubbles, or bubbles are likely to be generated by reboil. The lower limit of the SO content is 0.05% or more, and preferably 0.1% or more. The upper limit of the SO content is 0.5% or less. The range of SO is selected from any combination of these upper and lower limits.

[0040] (Total iron oxide (T Fe O))

The content of iron oxide is the total iron oxide (T Fe O) is from 0.05% to 0.35%. If the total iron oxide is less than 0.05%, Fe ³⁺ that absorbs in the ultraviolet region becomes too small, and the ultraviolet transmittance increases. On the other hand, if the total iron oxide exceeds 0.35%, Fe ³⁺ , which absorbs light in the visible short wavelength region, and too much Fe ^2+, which absorbs light on the visible long wavelength side, increase the visible light transmittance. Becomes low. The lower limit of the total iron oxide content is 0.05% or more, and preferably 0.1% or more. The upper limit of the content of total iron oxide is 0.35% or less, and preferably 0.25% or less. The range of total iron oxide is selected from any combination of these upper and lower limits.

[0041] (iron ratio)

The iron ratio, which is the ratio of FeO in terms of Fe O to total iron oxide, is sometimes called the FeO ratio. If the FeO ratio is less than 10%, too much Fe ³⁺ has an absorption in the visible short wavelength region, so the visible light transmittance is lowered and the yellow color of the glass becomes too strong. When the FeO ratio exceeds 40%, too much Fe ²⁺ is absorbed on the visible long wavelength side, so that the visible light transmittance is lowered and the blue color of the glass becomes too strong. The lower limit of the iron ratio is preferably 10% or more, more preferably 15% or more. The upper limit of the iron ratio is preferably 40% or less, more preferably 35% or less. The range of the iron ratio is selected from any combination of these upper and lower limits.

 [0042] (antimony oxide)

 Antimony oxide is a component that promotes clarification of glass. When glass containing antimony oxide is formed by the float process, for example, the glass is colored by the reducing atmosphere in the float bath. It is also a component that can be a burden on the environment. Therefore, in the present invention, antimony oxide is not substantially contained.

 In the present invention, “substantially not containing” means that the corresponding component is not actively added, and means that contamination as an unavoidable impurity is allowed. Even when the corresponding component is mixed as an unavoidable impurity, the content is preferably less than 0.1%.

[0044] The glass composition of the present invention may contain components other than the above components and unavoidable impurities as long as the effects of the present invention are not impaired. However, PO is a component that easily volatilizes and may cause defects during molding similar to BO and ZnO. Therefore, in the present invention, it is preferable that P o is not substantially included.

 [0045] For the glass composition of the present invention, a particularly preferred first composition is:

 SiO 65% or more, 75% or less,

 Al O 0.5% or more, less than 2%,

 B O 0% or more, 5% or less,

 Na O 6% or more, 9% or less,

 K O 4% or more, less than 10%,

 Li O 0% or more, less than 1%,

 Na O + K O + Li O 10% or more, 17.5% or less,

 MgO 0% or more, 5% or less,

 CaO over 6%, 12% or less,

 BaO 0% or more, less than 4%,

 SrO 0% or more, less than 4%,

 ZnO 0% or more, 5% or less,

 MgO + CaO + SrO + BaO + ZnO 10% or more, less than 15%,

 SrO + BaO + ZnO 0% or more, 5% or less,

 TiO 0% or more, 0.5% or less,

 ZrO 0% or more, 2.5% or less,

 CeO 0% or more, 0.5% or less,

 SO 0.05% or more, 0.5% or less, and

 Total iron oxide converted to Fe O 0.05% or more, 0.35% or less,

 It is.

 [0046] The first composition achieves a near thermal expansion coefficient and a lower softening point as compared with the current soda lime glass with a lower Na 2 O content than the current soda lime glass.

[0047] In the first composition, AlO is 0.5% or more and less than 1%, NaO is 7% or more and 9% or less, KO is 6% or more and less than 10%, LiO is 0.05. % Or more, less than 0.35%, MgO over 4%, 5% or less, SrO over 0%, less than 1%, TiO force S0% or more, less than 0.05%, ZrO More preferably, the force is S0% or more and less than 0.5%.

[0048] Regarding the glass composition of the present invention, a particularly preferred second composition is:

 SiO 67% or more, 73% or less,

 Al O> 0%, <2%,

 B O 0% or more, 5% or less,

 Na O 4% or more, 9% or less,

 K O 2% or more, 9% or less,

 Li O over 0%, 3% or less,

 Na O + K O + Li O 10% or more, 19.

 MgO over 0%, 6% or less,

 CaO over 5%, up to 10%,

 BaO 0% or more, less than 1%,

 SrO 4% or more, 7% or less,

 ZnO 0% or more, 6% or less,

 MgO + CaO + SrO + BaO + ZnO 10% or more, 19% or less,

 SrO + BaO + ZnO 0% or more, 10% or less,

 TiO 0% or more, 0.5% or less,

 ZrO 0% or more, 2.5% or less,

 CeO 0% or more, 0.5% or less,

 SO 0.05% or more, 0.5% or less, and

 Total iron oxide converted to Fe O 0.05% or more, 0.35% or less,

 It is.

 [0049] The second composition realizes a near thermal expansion coefficient and a lower softening point compared to the current soda lime glass with a lower Na 2 O content than the current soda lime glass! / And a glass composition having excellent formability.

[0050] In the second composition, AlO is 0.1% or more and less than 2%, NaO is 6% or more and 9% or less, LiO is 0.1% or more, 1.5% or less, MgO 2% or more, 6% or less, CaO 5.5% or more, 10% or less, TiO force S0% or more, less than 0.05%, ZrO force or more, less than 0.5% More preferably. Further, Si_〇 ₂ 68% or more, 72% or less, Al ₂ 〇 ₃ 0.5% or more and less than 2%, Na O is more than 7%, 9% or less, KO 4% or more, 8% or less, Li O is 0.1% or more, 1% or less, MgO is 2% or more, 5% or less, CaO is 5.5% or more, 8% or less, and SrO is 4% or more, 6% or less. preferable.

[0051] [Characteristics of glass composition]

 (Transmittance)

 As the glass for illumination, it is desirable that the visible light transmittance is high. Visible light is generated in a fluorescent lamp by using light emitted when the generated ultraviolet light is irradiated on a phosphor on the inner surface of the fluorescent lamp. Thus, ultraviolet rays are generated inside the fluorescent lamp. Since it is necessary to reduce the leakage of ultraviolet rays, the transmittance of wavelengths in the ultraviolet region must be kept low. Ultraviolet rays include light with wavelengths such as 254 nm and 313 nm. In the case of glass, light with a wavelength of 254 nm is hardly transmitted and therefore need not be considered. The transmission of light having a wavelength of 313 nm needs to be controlled, and can be controlled mainly by the contents of Fe 2 O and titanium oxide in the total iron oxide. The transmittance of light with a wavelength of 313 nm (glass thickness: 0.7 mm) is preferably 60% or less, and more preferably 45% or less.

 [0052] (Thermal expansion coefficient)

 When used as lighting glass, the thermal expansion coefficient of the glass needs to be balanced with the thermal expansion coefficient of the sealing glass used. This sealing glass is used for sealing an electrode inserted into the interior in the case of internal electrode type illumination, and is used for laminating sheet glass to form a glass container in the case of a surface illumination device. .

The [0053] commonly used are sealing glass, the thermal expansion coefficient is adjusted normally to balance the representative value of the thermal expansion coefficient of 89 X 10- ⁷ / ° C of the soda-lime glass composition. Therefore, it is desirable that the coefficient of thermal expansion of the lighting glass not be far from this value. Specifically, (89 ± 5) X 10- 7 /. It is desirable in the range of C (89 ± 4) X 10- 7 / ° and more desirable tool in the range of C (89 ± 2) X 10- 7 / ° more Nozomu be in the range of C Good.

 [0054] (softening point, glass transition point)

If the glass container for lighting is tubular, it is molded directly from the molten glass into a tubular shape. Or once formed into a tubular shape, it is heated to a temperature at which it is softened again and reshaped into a U shape. In the case of a surface illumination device, in order to form a glass container for illumination, the plate-like glass may be heated to a temperature at which it is softened again and used for press molding or the like. Therefore, it is preferable that the softening point is low so that the work can be easily performed in the molding by heating and reheating. It is desirable that the softening point is not so high compared to that of the current soda-lime glass composition. Specifically, the softening point is preferably 790 ° C or lower, about 50 ° C higher than the softening point of the soda-lime glass composition, and more preferably 750 ° C or lower, about 10 ° C higher. Furthermore, it is most desirable that the temperature be 740 ° C. or lower, which is lower than the softening point of the current soda-lime glass composition.

 [0055] In addition, since it is often difficult to measure the softening point !, this may be substituted by the glass transition point. In terms of glass transition point, less than 630 ° C is desirable, and less than 600 ° C is more desirable, with 565 ° C or less being most desirable.

 Here, (softening point glass transition point) is a parameter that serves as an index of the cooling rate after re-forming by reheating. The larger the (softening point glass transition point), the faster the glass cooling rate during cooling after re-forming by reheating. Therefore, productivity of remolding is improved. The cooling rate is given as a value obtained by dividing (softening point glass transition point) by the time required for cooling from the softening point to the glass transition point.

 [0057] The (softening point glass transition point) of the glass composition of the present invention has a value equal to or greater than the (softening point-glass transition point) of the current soda-lime glass composition. In the present invention, (softening point-glass transition point) in Examples 1, 3, 4 and 8-42 described later is a value exceeding 184 ° C. On the other hand, in the comparative example, the value is 184 ° C or lower. For this reason, in the said Example, it is possible to enlarge a cooling rate compared with a comparative example. That is, for the glass composition of the present invention, the cooling rate at the time of reshaping can be made equal to or greater than that in the prior art.

 [0058] (Glass forming method)

The glass composition of the present invention can be formed into tubular glass or sheet glass. In particular, the glass composition of the present invention, which is desired to be a float method capable of being manufactured at low cost and in large quantities, can be applied to the float method as a method for forming a sheet glass. Of course, as a fluorescent lamp It is also possible to form a general tubular shape. The specific molding method may be in accordance with a known method.

[0059] (Use of glass composition)

 The glass composition of the present invention, for example, as described above, using a glass article formed into a plate shape by a float method or the like, or a glass article formed into a container shape, and an illumination device such as a fluorescent lamp according to a known method (example: , Surface lighting devices, tubular fluorescent lamps, and the like).

[0060] Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

 Raw material batches (hereinafter sometimes referred to as batches) were prepared so that the glass compositions shown in Tables 1 to 4 were obtained. The raw materials used were those used for normal glass production.

[0061] [Table 1]

[0062] [Table 2] Composition (Poor%) Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16

Si0 ₂ 69.22 71.44 70.38 70.54 70.21 70.27 70.42 70.58

Al ₂ 0 ₃ 1.35 0.67 0.67 0.67 0.67 0.80 0.80 0.81

Li ₂ 0 ― ― One- ―

Na ₂ 0 6.56 8.02 7.99 8.01 7.97 7.99 8.00 8.02

K ₂ 0 6.17 8.13 9.27 8.90 8.86 9.26 8.90 8.53 20 12.73 16.2 17.3 16.9 16.8 17.2 16.9 16.5 gO 3.84 3.91 3.89 4.07 4.05 3.89 4.06 4.24

CaO 7.59 7.74 7.70 7.72 7.13 7.70 7.71 7.73

SrO 4.19 ― ― ― 1.02 One ―

BaO ― ― ― 一 one one one one

ZnO--One------

RO-1 15.61 11.64 1 1.59 1 1.79 12.19 11.59 1 1.78 11.97

RO-2 4.19 0.00 0.00 0.00 1.02 0.00 0.00 0.00

Ti0 ₂ 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02

Zr0 ₂ 1.00 ― ― ― ― ― ―.

Fe ₂ 0 ₃ 0.11 0.11 0.11 0.1 1 0.1 1 0.11 0.11 0.11 so ₃ 0.22 0.25 0.20 0.22 0.23 0.23 0.20 0.21

Ce0 ₂ 1 ― 1 1 ― 1 ―

Sb ₂ 0 ₃ ― ― ― ― ― ― ―

Na ₂ 0 / K ₂ 0 1.1 1.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9

FeO ratio (%) 27.3 25.1 29.7 26.8 28.2 27.8 29.5 28.9 Coefficient of thermal expansion (X 1 CT ⁷ / ° C) 77.0 94.3 94.7 92.5 89.0 95.0 94.0 92.0 Transition point (° C) 590 564 561 561 558 559 563 562 Softening point ( ° c) 786 754 747 749 746 746 749 752 Softening point first transition point (° C) 196 190 186 188 189 187 186 190

UV transmittance (313nm) 47.5 46.7 44.9 44.2 44.0 43.0 43.5 44.1 3]

Composition (% by weight) Example 17 Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 Example 24

_{Si0 2 71.53 71.75 71.05 70.10 70.35 70.61} 70.73 70.88

Al ₂ 0 ₃ 0.67 0.67 0.67 0.80 0.80 0.81 0.81 0.81

Li ₂ 0 0.15 0.49 ― ― 0.15 0.30 0.44 0.30

_{Na 2 0 8.03 8.06 7.98 7.97 7.99} 8.02 7.94 8.05

K ₂ 0 8.14 8.16 8.08 8.85 8.89 8.92 8.78 8.17

_{R 2 0 16.3 16.7 16.1 16.8 17.0} 17.2 17.2 16.5

MgO 3.91 3.93 3.56 4.04 4.06 4.07 4.01 4.26

CaO 7.46 6.84 7.23 7.13 7.15 7.18 7.19 7.43

SrO 1 1 1 1.02 0.51 1 ― ―

BaO ― ― ― ― One one ― ―

ZnO ― 1.33 ― ― ― ― One

RO-1 1 1.38 10.76 12.12 12.19 11.72 11.25 11.20 11.69

RO-2 0.00 0.00 1.33 1.02 0.51 0.00 0.00 0.00

Ti0 ₂ 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02

Zr0 ₂ ― ― ―One one ―― One ―

_{Fe 2 0 3 0.11 0.11 0.11 0.13} 0.13 0.13 0.13 0.20 so 3 0.22 0.22 0.20 0.23 0.22 0.22 0.22 0.22

Ce0 ₂ ― ― ― ― ― ― ―

Sb ₂ 0 ₃ —— One — — —— ——

Na ₂ 0 / K ₂ 0 1.0 1.0 1.0 0.9 0.9 0.9 0.9 1.0

FeO ratio (%) 26.1 26.5 31.3 25.5 28.8 28.7 28.6 27.0 thermal expansion coefficient ^{(X 10- 7 / ° c)} 91.5 89.0 88.5 91.1 91.7 90.2 91.1 92.4 Transition point (° C) 552 532 562 560 550 541 536 546 Softening point ( ° C) 744 726 749 746 739 730 724 735 Softening point one transition point (° C) 192 194 187 186 189 189 188 189

UV transmittance (313nm) 45.9 46.5 47.0 42.3 44.3 44.1 43.2 35.8 Visible light transmittance (%) ― One ― 91.5 91.5 91.3 91.4 ― 4]

Composition (mass%) Example 25 Example 26 Example 27 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5

SiO _z 71.01 71.15 71.28 72.63 71.0 69.8 71.0 69.2

_{ΑΙ 2 θ 3 0.81 0.81 0.81 1.4} 1.7 1.0 1.5 0.1

Li ₂ 0 0.30 0.30 0.45 ― ― 1.6

Na ₂ 0 8.07 8.08 8.00 13.1 13.6 7.4 5.5 8.0

K ₂ 0 7.80 7.42 7.28 0.9 1.0 7.5 4.0 8.1

R ₂ 0 16.2 15.8 15.7 14.0 14.6 16.5 9.5 16.2

MgO 4.33 4.44 4.38 4.0 4.0 2.2 1.0 0.04

CaO 7.59 7.70 7.71 7.91 8.0 6.5 3.0 6.85

SrO 1.0 6.0 ―

BaO ― ― 1― ― ― 2.5 6.0 2.01

ZnO ― ― ― ― ― ― ― 4.2

RO-1 1 1.92 12.13 12.09 1 1.9 12.0 12.2 16.0 13.1

RO-2 0.00 0.00 0.00 0.00 0.0 3.5 12.0 6.2

Ti0 ₂ 0.02 0.02 0.01 0.02 0.03 ― ― 0.4

Zr0 ₂ 1 1 1-

_{Fe 2 0 3 0.20 0.20 0.20 0.1} 1 0.53 one - 0.01

S0 ₃ 0.22 0.21 0.22 0.2 0.17 One ― 0.35

Ce0 ₂ 1 0.5-

Sb ₂ 0 ₃ 0.5 0.5 0.36

B ₂ 0 ₃ 1.0 ―

Na ₂ 0 / K ₂ 0 1.0 1.1 1.1 15.1 13.6 1.0 1.4 1.0

FeO ratio (%) 26.5 26.1 27.0 22.0 24.5 —One ― 3.6 Thermal expansion coefficient (x ¹ 0 ⁷ / ° C) 91.0 88.1 89.8 90.9-94.0 94.0 95.0 Transition point (° C) 551 550 544 563 ― ― 501 570 Softening Point (° C) 736 739 733 740 ― ― 680 Softening point one transition point (° C) 185 189 189 177 ― 1 179

 UV transmittance (313nm) 36.1 35.7 35.2 36.0 ― ― ― 77.1 Visible light transmittance (¾) ― ― ― 91.3 89.3 ―

[0065] (Table;! To 4, in which RO is Na O + KO + Li O, RO-1 is MgO + CaO + SrO + BaO + ZnO, RO-2 is SrO + BaO + ZnO Is shown.)

 [0066] The formulated batch was melted and clarified in a platinum crucible. First, the crucible was held in an electric furnace set at 1500 ° C. for 4 hours to melt the batch. Thereafter, the glass melt was poured onto an iron plate to obtain a plate-like glass body. This glass body was held in another electric furnace set at 650 ° C for 1 hour, and then cooled to room temperature at a cooling rate of 2 ° C per minute. This slowly cooled glass body was used as a sample glass.

 [0067] (Measurement of transmittance)

The transmittance of the obtained sample glass was measured with a spectrophotometer (manufactured by Hitachi, Ltd., U4100) using A light source. The thickness of the glass substrate was 0.7 mm. UV transmission As a measure of the excess rate, the transmittance of light having a wavelength of 313 nm was measured. Further, the visible light transmittance was measured according to the method for measuring visible light transmittance of JIS R 3106.

[0068] (Composition analysis)

 The composition of the obtained sample glass was quantitatively analyzed using fluorescent X-ray analysis and chemical analysis.

 [0069] (Measurement of thermal expansion coefficient)

 The thermal expansion coefficient of some of the obtained sample glasses was measured with a differential thermal dilatometer (manufactured by Rigaku, TAS-100). The sample size is 5 mm in diameter and 17 mm in length. The sample is measured from room temperature to the yield temperature at a heating rate of 5 ° C / min, and the coefficient of thermal expansion is in the range of 50 ° C to 300 ° C. Calculated.

[0070] (Measurement of softening point and glass transition point)

 The intrusion indenter of the obtained sample glass was lowered to a flat sample with a constant load, and the viscosity was calculated from the penetration speed of the indenter to obtain the softening point.

 The glass transition point was determined from the inflection point in the thermal expansion curve determined by the above-described measurement of the thermal expansion coefficient.

[0071] (Measurement of devitrification temperature)

 The sample glass pulverized to a particle size of 1.0 to 2.8 mm is placed in a platinum boat and held in an electric furnace with a temperature gradient for 2 hours. From the maximum temperature at which the crystal appears, devitrification occurs. The temperature was determined.

[0072] (Measurement of molding temperature)

 The viscosity of the glass was determined by the ordinary platinum ball pulling method, and the temperature (forming temperature) at which the viscosity of the glass reached 10000 dPas (10000 poise) was determined.

[0073] The above measurement results are also shown in Tables !! to 4.

[0074] In Examples;! To 27, the Na 2 O content is 4.37% to 10.8%, the Na 2 O / K 0 is 0.3 to 2.6, and the thermal expansion coefficient is (74. ^{7-95. 6) X 10- 7 /} ° C, transition point Ru 532 ° C~622 ° C der. In other words, it has less Na 2 O content than the current soda-lime glass and has properties that are relatively close to it, and it has suitable characteristics as a glass composition for lighting.

[0075] In Example 2;! To 27, the Na 2 O content is 7.94% to 8.08%, and the Na 2 O / K 0 is 0 · 9 ~ 1.1, thermal S tension coefficient force (88. 1-92.4) X IO /. C, transition ^ (force 536. C ~ 551 ° C, softening point 724 ° C ~ 739 ° C. That is, the current soda lime with a much lower Na 2 O content than the current soda lime glass. Compared to glass, it has a very close thermal expansion coefficient and a lower softening point, which makes it particularly suitable as a lighting glass composition.

 [0076] Comparative Example 1 is a general soda-lime glass composition for sheet glass. It contains a large amount of Na 2 O as 13.1% and is outside the glass composition range of the present invention. Also, it contains almost no K 2 O and Na 2 O / K 2 O is 15.1.

 [0077] Comparative Example 2 is a soda-lime-based glass composition containing a large amount of iron for a general plate glass.

 [0078] Comparative Example 3 is the glass composition disclosed in Example 8 of Japanese Patent Application Laid-Open No. 05-314169, and does not contain SO as a fining agent and contains SbO.

 [0079] Comparative Example 4 is a glass composition described in Example 7 of JP-A-11 224649, and is a glass composition having a small content of CaO and a small content of CaO. The Furthermore, as a clarifier, it does not contain SO but contains CeO and SbO.

 [0080] Comparative Example 5 is a glass composition containing Sb 2 O as a fining agent and having a very small FeO ratio.

 [0081] Comparative examples 3 and 4 are examples that do not contain SO. Comparative Examples 3 and 4 both contain Sb 2 O as a fining agent, and Comparative Example 4 further contains CeO. When the glass compositions of Comparative Examples 3 and 4 are molded by the float process, they are colored brown by the reducing atmosphere in the float bath. Furthermore, in Comparative Example 4, it is colored yellow by irradiation with ultraviolet rays.

 In Comparative Example 2, since the iron content is large, the visible light transmittance is 89.3%, which is lower than that in Examples 20-23.

 [0083] Notches were prepared so that the glass compositions shown in Tables 5 and 6 were obtained. Examples 28-42 are glass compositions containing about 4.5% SrO. Comparative Example 6 is a general soda-lime glass composition for sheet glass. It contains a large amount of Na 2 O as 13.12% and is outside the glass composition range of the present invention. Moreover, it contains almost no K 2 O and Na 2 O / K 2 O is 11.82.

[0084] [Table 5] Composition (% by weight) Example 28 Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 Example 35

_{Si0 2 69.35 70.35 68.95 69.33 71.66 72.07} 70.46 70.60

Al ₂ 0 ₃ 0.79 0.81 0.79 0.79 0.80 0.80 0.80 0.80

_{Li 2 0 0.30 0.30 0.29 0.54 0.30} 0.54 0.30 0.30

Na ₂ 0 5.20 8.03 7.88 7.92 7.96 8.01 7.92 7.93

K ₂ 0 7.66 3.58 7.62 6.90 4.63 3.88 5.98 5.83

R ₂ 0 13.16 1 1.91 15.79 15.36 12.89 12.43 14.20 14.06

MgO 3.96 4.02 3.22 3.23 3.25 3.27 3.23 3.24

CaO 7.85 7.96 6.37 6.40 6.44 6.47 6.40 6.41

SrO 4.54 4.61 4.52 4.54 4.57 4.59 4.55 4.55

BaO

 RO-1 16.35 16.59 14.1 1 14.17 14.26 14.33 14.18 14.20

RO-2 4.54 4.61 4.52 4.54 4.57 4.59 4.55 4.55

Ti0 ₂ 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02

Zr0 ₂

Fe ₂ 0 ₃ 0.12 0.13 0.12 0.12 0.13 0.13 0.12 0.12

S0 ₃ 0.21 0.19 0.22 0.21 0.24 0.22 0.22 0.20

Ce0 ₂ ― ― ― ― ― One ―

Sb ₂ 0 ₃

_{Na 2 0 / K 2 0 0.68} 2.24 1.03 1.15 1.72 2.06 1.32 1.36

FeO ratio (%) 19.1 22.3 20.9 Devitrification temperature (° C) 1073 1063 943 930 971 1033 951 960 Molding temperature (c) 1048 1027 1029 1017 1056 1044 1052 1053 Molding temperature One devitrification temperature (° c) -25 -36 86 87 85 1 1 101 93 Thermal expansion coefficient (X 1 0— ⁷ Z ° C) 88.5 85.2 94.2 93.8 84.7 83,7 89.5 88.6 Transition point (° c) 561 555 536 526 546 539 545 543 Softening point (° C) 747 741 724 716 744 735 734 736 Softening point one transition point (° C) 186 186 188 190 1 Θ8 1 Θ6 189 193

UV transmittance (313nm) 1 1 1-1 1 34.7 34.7 36.7 Visible light transmittance (%)---1 1 1 91.5 91.4 91.5 6]

Composition (% by weight) Example 36 Example 37 Example 38 Example 39 Example 40 Example 41 Example 42 Comparative Example 6

Si0 ₂ 70.27 69.55 69.72 69.49 69.61 69.63 69.60 72.05

Alj0 ₃ 0.99 1.81 1.82 1.81 1.82 1.82 1.57 1.38

Li ₂ 0 0.30 0.29 0.39 0.34 0.36 0.43 0.34 0

Na ₂ 0 7.92 7.89 7.91 7.89 7.90 7.91 7.90 13.12

K ₂ 0 5.98 5.96 5.66 5.96 5.81 5.67 6.12 1.1 1

R ₂ 0 14.20 14.14 13.96 14.19 14.07 14.01 14.36 14.23

MgO 3.23 3.22 3.23 3.22 3.22 3.23 3.22 4.02

CaO 6.40 6.38 6.39 6.38 6.38 6.39 6.38 7.98

SrO 4.54 4.53 4.53 4.53 4.53 4.54 4.53 0

BaO

 RO-1 14.17 14.13 14.15 14.13 14.13 14.16 14.13 12.00

RO-2 4.54 4.53 4.53 4.53 4.53 4.54 4.53 0

Ti0 ₂ 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02

Zr0 ₂

Fe ₂ 0 ₃ 0.12 0.14 0.14 0.14 0.14 0.14 0.11 0.1 1 so ₃ 0.23 0.21 0.19 0.22 0.21 0.22 0.20 0.21

Ce0 ₂ ― ― ― ― ― ― ―

Sb ₂ 0 ₃

Na ₂ 0 / K ₂ 0 1.32 1.32 1.40 1.32 1.36 1.40 1.29 1 1.82

FeO ratio (%) 24.7 21.0 20.8 Devitrification temperature (° C) 955 990 1006 986 1008 992 978 978 Molding temperature (° C) 1053 1060 1055 1056 1056 1052 1050 1025 Molding temperature One devitrification temperature (° c) 98 70 49 70 48 60 72 47 Thermal expansion coefficient (X 1 0— ⁷ / ° C) 90.3 88.5 87.7 87.4 87.2 87.4 88.5 87.8 Transition point (° C) 545 551 546 543 544 543 540 556 Softening point (° c) 736 742 738 739 740 737 736 734 Softening point one transition point (° C) 191 191 192 196 196 194 196 178

UV transmittance (313nm) ― ― 1 1 27.8 40.7 42.6 Visible light transmittance 00 ― ― ― ― ― 91.3 91.4 91.6

[0086] (In Tables 5 and 6, RO represents Na O + KO + Li O, RO-1 represents MgO + CaO + SrO + BaO + ZnO, and RO-2 represents SrO + BaO + ZnO. .)

In Examples 28 to 42, the Na 2 O content was 5.20% to 8.03%, the Na 2 O / K Ο was 0 · 68 to 2 • 24, and the thermal expansion coefficient was (83.7− ^{94. 2) X 10- 7 / °} C, transition point of 526 ° C~561 ° C. In other words, it has less Na 2 O content than the current soda-lime glass and has properties that are relatively close to it, and it has suitable characteristics as a glass composition for tube bulbs. In Example 35, the transmittance at a wavelength of 313 nm was 36.7% and the transmittance for visible light was 91.5%. In Example 41, the transmittance at a wavelength of 313 nm was 27.8%, and visible light was visible. Transmittance The power was 3%.

 [0088] Hereinafter, an example in which a glass composition according to the present invention is formed into a plate shape by a float process and a surface illumination device is configured using the glass substrate will be described.

[0089] (Application 1)

 Application Example 1 is a surface illumination device in which a casing is formed using the glass substrate described above. Figure 1 shows a schematic cross-sectional view of a surface illumination device according to Application Example 1. In the surface lighting device 1, first, a flat plate-like first glass substrate 11 and a second glass substrate 12 having a U-shaped cross section are press-molded to join a glass frit 13 to form a container, and the interior is a space. S. A pair of discharge electrodes 14 and 14 are provided at both ends inside the container. Further, phosphors 15 and 15 are coated on the surfaces facing the space S in the first glass substrate 11 and the second glass substrate 12. Furthermore, mercury and an inert gas such as argon are sealed in the space S inside the container.

 [0090] When a voltage is applied to the discharge electrodes 14 and 14, the ultraviolet rays are generated. This ultraviolet light enters the phosphors 15 and 15 and emits visible light, which functions as a lighting device.

 [0091] Since the glass substrate according to the present invention has a reduced sodium content, the surface illumination device 1 configured using the glass substrate has a feature that a blackening phenomenon due to sodium elution hardly occurs.

 [0092] (Application 2)

 Application Example 2 uses the above-mentioned two glass substrates and provides a large number of partition walls between them to form a large number of cells to form a surface illumination device. Figure 2 shows a schematic cross-sectional view of a surface illumination device according to Application Example 2. The surface lighting device 2 holds two glass substrates 21 and 22 at a constant interval, and provides a large number of partition wall portions 23 ··· (where · · · represents a large number) between them, Cell S is constructed. Further, phosphors 25 and 25 are coated on the surfaces of the glass substrates 21 and 22 facing the cell S. Further, the cell S is sealed with mercury and an inert gas such as argon. The surface illumination device 2 is caused to discharge by applying voltage to an electrode (not shown) to function as a light source.

[0093] (Application 3)

Application Example 3 is a surface illumination device having a structure in which a large number of cells are provided as in Application Example 2. application In Example 2, the force S provided with a large number of partition walls to separate a large number of cells, and in Application Example 3, one glass substrate was press-molded to form a large number of ridges, so that the joints became the partition walls. It has been made.

 FIG. 3 shows a partially enlarged perspective view of the surface illumination device 3 according to the application example 3. As shown in FIG. The surface illumination device 3 is configured by first joining a flat plate-like first glass substrate 31 and a second glass substrate 32 formed by press molding into a shape in which a large number of ridges are arranged in parallel to constitute a large number of cells S. is there. At this time, the bonding portion 33 of the second glass substrate 32 bonded to the first glass substrate 31 is a partition wall portion. Further, phosphors 35 and 35 are coated on the surfaces of the glass substrates 31 and 32 facing the cell S. Further, the cell S is filled with mercury and an inert gas such as argon. The surface illumination device 3 is discharged by applying a voltage to an electrode (not shown) to function as a light source.

 Industrial applicability

[0095] A glass article obtained by molding the glass composition of the present invention is useful as an illumination glass such as a phosphor.

Claims

The scope of the claims

 Display in mass%,

 SiO 65% or more, 75% or less,

 Al O 0% or more, less than 5%,

 B O 0% or more, 5% or less,

 Na O> 3%, <12%,

 K O 2% or more, 15% or less,

 Li O 0% or more, less than 5%,

 Na O + K O + Li O 6% or more, 20% or less,

 MgO 0% or more, 10% or less,

 CaO over 5%, 15% or less,

 BaO 0% or more, less than 4%,

 SrO 0% or more, 10% or less,

 ZnO 0% or more, 10% or less,

 MgO + CaO + SrO + BaO + ZnO over 5%, 19% or less,

SrO + BaO + ZnO 0% or more, 10% or less,

 TiO 0% or more, 0.5% or less,

 ZrO 0% or more, 2.5% or less,

 CeO 0% or more, 0.5% or less,

 SO 0.05% or more, 0.5% or less, and

 Total iron oxide converted to Fe O 0.05% or more, 0.35% or less,

Comprising

 A glass composition characterized by being substantially free of antimony oxide. In the glass composition according to claim 1,! /

 The glass composition is expressed in mass%,

 SiO 65% or more, 75% or less,

 Al O> 0%, <2%,

BO 0% or more, 5% or less, Na O 4% or more, 9% or less,

 K O 2% or more, less than 10%,

 Li O 0% or more, less than 5%,

 Na O + K O + Li O 10% or more, 19.

 MgO 0% or more, 6% or less,

 CaO over 5%, up to 12%,

 BaO 0% or more, less than 4%,

 SrO 0% or more, 10% or less,

 ZnO 0% or more, 10% or less,

 MgO + CaO + SrO + BaO + ZnO 10% or more, 19% or less,

 SrO + BaO + ZnO 0% or more, 10% or less,

 TiO 0% or more, 0.5% or less,

 ZrO 0% or more, 2.5% or less,

 CeO 0% or more, 0.5% or less,

 SO 0.05% or more, 0.5% or less, and

 Total iron oxide converted to Fe O 0.05% or more, 0.35% or less,

 A glass composition comprising:

 [3] In the glass composition according to claim 2,

 Al O is 0.5% or more, less than 2%,

 Na O is 6% or more, 9% or less,

 O is 4% or more, less than 10%,

 Li O is 0% or more, less than 1%,

 (Na O + K O + Li O) is 10% or more, 17.5% or less,

 MgO is 0% or more, 5% or less,

 CaO is more than 6%, 12% or less,

 SrO is 0% or more, less than 4%,

 ZnO is 0% or more, 5% or less,

(MgO + CaO + SrO + BaO + ZnO) is 10% or more, less than 15%, and The glass composition, wherein (SrO + BaO + ZnO) is 0% or more and 5% or less.

 In the glass composition according to claim 3, the Al O is 0.5% or more, less than 1%,

 Na O is 7% or more, 9% or less,

 O is 6% or more, less than 10%,

 Li O is 0.05% or more, less than 0.35%, MgO is more than 4%, 5% or less,

 SrO is 0% or more, less than 1%,

 TiO force S0% or more, less than 0.05%, and ZrO force SO% or more, less than 0.5%,

A glass composition.

 The glass composition according to claim 2, wherein the SiO force S67% or more, 73% or less,

 O is 2% or more, 9% or less,

 Li O is more than 0%, 3% or less,

 MgO is more than 0%, 6% or less,

 CaO is more than 5%, 10% or less,

 SrO is 4% or more, 7% or less,

 ZnO is 0% or more and 6% or less, and BaO is 0% or more and less than 1%,

A glass composition.

 In the glass composition according to claim 5, the Al O is 0.1% or more, less than 2%,

 Na O is 6% or more, 9% or less,

 Li O is 0.1% or more, 1.5% or less, MgO is 2% or more, 6% or less,

CaO is 5.5% or more, 10% or less, The TiO force S0% or more, less than 0.05%, and

 ZrO force SO% or more, less than 0.5%,

A glass composition.

 The glass composition according to claim 6,

 SiO force S68% or more, 72% or less,

 Al O is 0.5% or more, less than 2%,

 Na O is 7% or more, 9% or less,

 O is 4% or more, 8% or less,

 Li O is 0.1% or more, 1% or less,

 MgO is 2% or more, 5% or less,

 The CaO is 5.5% or more, 8% or less, and

 SrO is 4% or more, 6% or less,

A glass composition.

 In the glass composition according to claim 1,! /

 A glass composition, wherein the total iron oxide is 0.1% or more and 0.25% or less.

 In the glass composition according to claim 1,! /

 Of the total iron oxide, the ratio force of FeO converted to Fe O 10% -4% of the total iron oxide

A glass composition that is 0%.

 The glass composition according to claim 9,

 FeO percentage force S converted to Fe 2 O in the total iron oxide, 15% to 35% of the total iron oxide

% Glass composition.

 In the glass composition according to claim 1,! /

 The glass composition having a ZrO force SO% or more and less than 0.2%.

 In the glass composition according to claim 1,! /

 The glass composition which the said glass composition does not contain BaO substantially.

 In the glass composition according to claim 1,! /

 The glass composition, wherein the glass composition is substantially free of CeO.

In the glass composition according to claim 1,! / The glass composition, wherein the glass composition contains substantially no BO.

 twenty three

 [15] The glass composition according to claim 1! /,

 The glass composition, wherein the glass composition does not substantially contain ZnO.

[16] In the glass composition according to claim 1,! /

 A glass composition having a light transmittance of 313 nm or less of light of 60% or less when the glass composition has a thickness of 0.7 mm.

[17] The glass composition according to claim 16,

 A glass composition having a transmittance of light of a wavelength of 313 nm of 45% or less when the glass composition has a thickness of 0.7 mm.

[18] In the glass composition according to claim 1,! /

Thermal expansion coefficient in the range of ^{(89 ± 5) X 10- 7} / ° C, the glass composition.

[19] The glass composition according to claim 18,

Thermal expansion coefficient in the range of ^{(89 ± 2) X 10- 7} / ° C, the glass composition.

[20] In the glass composition according to claim 1,! /,

 A glass composition having a softening point of 790 ° C or lower.

[21] The glass composition according to claim 20,

 The glass composition whose softening point is 750 degrees C or less.

[22] In the glass composition according to claim 21,! /

 A glass composition having a softening point of 740 ° C or lower.

[23] A glass article comprising the glass composition according to claim 1 and formed into a plate shape.

24. The glass article according to claim 23, wherein the forming is performed by a float process.

[25] The glass article according to claim 23, which is used for a glass container for lighting.

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 26. The glass article for illumination according to claim 25, wherein the illumination is a fluorescent lamp.

 [27] A glass article comprising the glass composition according to claim 1 and used for a glass container for lighting.

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28. The glass article for illumination according to claim 27, wherein the illumination is a fluorescent lamp. / v: / O / -00ifcl £ /-/-8S80SAVε-