JP2000086279A - Glass for funnel of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass for the funnel of a cathode-ray tube having a specified X-ray absorption coefficient or above and ensuring a specified amount or less of lead leached in water by providing a specified composition consisting of SrO, BaO and PbO. SOLUTION: The glass contains >=1.0 wt.% SrO and >=1.0 wt.% BaO and has a PbO to (PbO+SrO+BaO+CaO+MgO) weight ratio of <=0.69. The glass has >=40 cm-1 X-ray absorption coefficient at 0.06 nm wavelength and the amount of lead leached from the glass in water is <=1.0 μg/cm2. The glass consists preferably of, by weight, 45-60% SiO2, 0-6% A12O3, 3-11% Na2O, 3-11% K2O, 5-24% PbO, 1-14% SrO, 1-2% Bad, 0-5% Cab, 0-5% MgO, 0-2% ZnO, 0-4% ZrO2, 0-0.9% TiO2 and 0-1% Sb2O3. These components can be quantitatively ensured as industrial resources.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to glass used for a funnel of a cathode ray tube used for television reception, computer terminal display, and the like.

[0002]

2. Description of the Related Art A cathode ray tube is constituted by a panel for displaying an image, a neck for accommodating an electron gun, and a funnel for connecting the two. Each of these three parts is formed into a desired shape in a separate process and then joined to form a cathode ray tube.

In a cathode ray tube, a high voltage is applied to an anode to emit electrons to irradiate the phosphor in order to emit light from the phosphor applied to the inner surface of the panel. Since X-rays are generated at this time, the glass used for the cathode ray tube is required to have an X-ray absorption function. However, these three parts of the glass are required to have different properties besides the X-ray absorption function, and are made of glasses having different compositions. That is, in order to block the generated X-rays and prevent the panel from being colored by the X-rays, SrO or BaO is used as a component for blocking the X-rays, and PbO is not used.
Since the funnel is required to have an X-ray absorption function higher than that of the panel, a large amount of PbO having an X-ray absorption coefficient larger than that of SrO or BaO is used as an X-ray shielding component.

[0004]

Some of the cathode ray tubes whose life has expired are recovered and reused, while others are stored as industrial waste in a controlled place. Among them, the cathode ray tube whose life has been stored and managed outdoors is exposed to long-term rainwater, and glass components may be melted out. In particular, there is a possibility that lead may be dissolved from the conventional funnel or neck glass containing lead.

[0005] In recent years, as a countermeasure against the lead elution problem, a funnel glass having a small amount of lead elution into water has been required. To a glass for a cathode ray tube funnel to reduce the lead elution amount of water, the glass of PbO which is one of the main components in JP 7-206468 was replaced by Bi ₂ O ₃ is,
JP-A-8-290937 proposes a glass to which TiO ₂ is added. However, when the content of Bi ₂ O ₃ or TiO _{2 in} the glass for funnels is increased, the production amount of the cathode ray tube is extremely large, so that problems such as depletion of bismuth resources or titanium resources and soaring of production costs occur. There is a risk.

An object of the present invention is to provide a glass for a funnel, which is used for conventional glass for a funnel of a cathode ray tube and is composed of a component which can be secured quantitatively as an industrial resource, and has a small amount of lead eluted into water.

[0007]

According to the present invention, when the composition is expressed in terms of% by weight on an oxide basis, the content of SrO is 1.0% by weight or more and the content of BaO is 1.0% by weight. Above, and the PbO content of PbO, SrO, BaO,
The weight ratio to the total content of CaO and MgO is 0.6
9 or less, a glass for a cathode ray tube funnel,
A glass for a cathode ray tube funnel having a lead elution amount A of the glass measured by the following method A of 1.0 μg / cm ² or less and an X-ray absorption coefficient at a wavelength of 0.06 nm of 40 cm ⁻¹ or more. (First invention). (Method A) The glass is immersed in distilled ion-exchanged water at 90 ° C. for 20 hours and then taken out. The amount of lead in the distilled ion-exchanged water is measured by inductively coupled plasma emission spectroscopy, and the measured value of the amount of lead divided by the surface area of the glass is defined as the amount of lead elution A.

[0008] The present invention also relates to a method for determining the composition by weight on an oxide basis.
%, The content of SrO is 1.0% by weight.
% Or more, the content of BaO is 1.0% by weight or more, and Z
rO _TwoIs 0.3 wt% or more.
A glass for a channel, which is measured by the following method B.
The lead elution amount B of the glass obtained was 4.0 μg / cm.^TwoBelow
X-ray absorption coefficient at wavelength 0.06 nm is 40c
m^-1Glass for a cathode ray tube funnel,
(Second invention). (Method B) Glass was placed in distilled ion-exchanged water at 90 ° C for 20 hours.
After immersion, the glass is taken out. This distilled ion exchange water
After adding concentrated nitric acid, the amount of lead
Measured by optical analysis and the measured amount of lead
The lead elution amount B is obtained by dividing by the surface area of the lead.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The lead elution amount A in the first invention is
The amount of lead eluted from the glass into distilled ion-exchanged water when the glass was immersed in distilled ion-exchanged water at 90 ° C. for 20 hours was expressed in μg /
It is expressed in cm ² . Here, distilled ion-exchanged water is produced by once distilling tap water and passing it through an ion-exchange resin. The amount of lead is measured by inductively coupled plasma emission spectroscopy (IPC) at the time when seven days have passed since the end of the glass immersion.

The lead elution amount A of the glass for a cathode ray tube funnel of the first invention (hereinafter simply referred to as the glass of the first invention) is 1.0 μg / cm ² or less, and the conventional glass for a cathode ray tube funnel (hereinafter simply referred to as the conventional glass). The amount of lead eluted A (about 1.2 μg / cm ² ) is smaller than
Excellent in terms of environmental protection. Preferably 0.9 μg / c
m ² or less, more preferably 0.7 μg / cm ² or less.

When the composition of the glass of the first invention is expressed in terms of% by weight on an oxide basis, the PbO content of PbO, S
If the weight ratio of the total content of rO, BaO, CaO, and MgO exceeds 0.69, the lead elution amount may be too large. Preferably it is 0.67 or less.

The lead elution amount B in the second invention is measured as follows. (1) Immerse glass (about 5 cm square, about 3 mm thick) in 100 cc of distilled ion-exchanged water at 90 ° C. for 20 hours. (2) Take out the glass from the distilled ion-exchanged water,
Within 4 hours, add 0.3 cc of concentrated nitric acid to the immersion liquid. (3) The amount of lead in distilled ion-exchanged water is measured by IPC seven days after the end of the glass immersion, and this is defined as the weight of the eluted lead. (4) The weight of the eluted lead per unit surface area of the glass is defined as a lead elution amount B (unit: μg / cm ² ).

The lead elution amount B of the glass for a cathode ray tube funnel of the second invention (hereinafter simply referred to as the glass of the second invention) is 4.0 μg / cm ² or less, and the lead elution amount B (4. (About 6 μg / cm ² ), which is excellent in environmental protection. Preferably 3.6 μg / cm
² or less, more preferably 3.0 μg / cm ² or less, particularly preferably 2.3 μg / cm ² or less.

When the lead elution amount A and the lead elution amount B for the same glass are compared, the lead elution amount B is usually larger than the lead elution amount A. The reason is presumed to be as follows. In the measurement of the lead elution amount A, the lead eluted from the glass into the distilled ion-exchanged water,
During the elapse of time until the C measurement, the hydroxide gradually precipitates as a hydroxide, and the lead that has become the hydroxide does not start the measurement of the IPC. On the other hand, in the measurement of the lead elution amount B, nitric acid is added within 24 hours from the end of immersion in the glass, whereby the progress of the hydroxide of lead is suppressed. As a result IP
The amount of lead in the measurement of C is larger in the case of the lead elution amount B than in the case of the lead elution amount A.

When the composition of the glass of the second invention is expressed in terms of% by weight on an oxide basis, if the ZrO ₂ content is less than 0.3% by weight, the lead elution B becomes too large. It is preferably at least 0.4% by weight, more preferably at least 0.5% by weight, further preferably at least 1% by weight, particularly preferably at least 2% by weight.
% By weight or more. Further, it is preferably at most 4% by weight. If it exceeds 4% by weight, the X-ray absorption function may be reduced. It is more preferably at most 3.5% by weight, particularly preferably at most 3% by weight.

The X-ray absorption coefficient of the glass of the first invention and the second invention (hereinafter collectively referred to as the present invention) at a wavelength of 0.06 nm is 40 cm ^-1 or more.
Has a line absorption function. It is preferably at least 50 cm ^-1 , more preferably at least 60 cm ^-1 , particularly preferably at least 65 cm ^-1.
That is all. The X-ray absorption coefficient μ is calculated by the following equation. μ = Σ (f _i × W _i ) × ρ ÷ 100 where f _i is the content (unit:% by weight) of each component constituting the glass as an oxide, and W _i is the wavelength of 0.06 nm. mass absorption coefficient thereof the oxide in (unit: cm ² / g), ρ is the density of the glass (unit: g /
cm ³ ).

In the case where the composition of the glass of the present invention is expressed in terms of weight% on an oxide basis, if the content of SrO is less than 1% by weight, the effect of reducing the lead elution amount becomes small. It is preferably at least 1.5% by weight, more preferably at least 2% by weight, particularly preferably at least 3% by weight.

When the composition of the glass of the present invention is expressed in terms of% by weight on an oxide basis, if the content of BaO is less than 1% by weight, the alkali resistance of the glass is lowered and the weather resistance is deteriorated. Preferably 1.5% by weight or more, more preferably 2% by weight.
% By weight or more, particularly preferably 3% by weight or more.

The softening point of the glass of the present invention is preferably 650 ° C. or higher. If the temperature is lower than 650 ° C., the glass may be deformed at the time of fusing with the neck or frit sealing with the panel. It is more preferably at least 655 ° C, particularly preferably at least 660 ° C. The softening point is preferably 680 ° C. or lower. If it exceeds 680 ° C., the viscosity may increase significantly as the temperature rises, which may make molding more difficult. More preferably 67
0 ° C. or less.

The average linear coefficient of expansion of the glass of the present invention at 0 ° C. to 300 ° C. (hereinafter simply referred to as the coefficient of thermal expansion) is 94 ×.
It is preferably at least 10 ^-7 / ° C.
It is preferably at most ^-7 / ° C. In the case of less than 94 × 10 ⁻⁷ / ° C. or more than 99 × 10 ⁻⁷ / ° C.,
Alternatively, there is a possibility that residual strain is generated between the frit seal and the seal. It is more preferably at least 95 × 10 ⁻⁷ / ° C., and even more preferably at most 98 × 10 ⁻⁷ / ° C. Devitrification temperature (temperature at which crystals precipitate) of the glass of the present invention
Is preferably 1100 ° C. or lower. More preferably, it is 1050 ° C or lower.

The glass of the first invention has a weight percentage of oxide
Substantially the composition expressed by the _{display, SiO 2 45~60, Al 2 O} 3 0~6, Na 2 O 3~11, K 2 O 3~11, PbO 5~24, SrO 1~14, BaO 1 To 21, CaO 0 to 5, MgO 0 to 5, ZnO 0 to 2, ZrO ₂ 0 to 4, TiO ₂ 0 to 0.9, and Sb ₂ O ₃ 0 to 1.

The composition expressed in terms of% by weight on an oxide basis is substantially: SiO ₂ 49-55, Al ₂ O ₃ 0.1-5, Na ₂ O 4-10, K ₂ O 4-10, PbO 15-24, SrO 2-9, BaO 2-11, CaO 0-4, MgO 0-3, ZnO 0-1, ZrO ₂ 0-4, TiO ₂ 0-0.9, Sb ₂ O ₃ 0-1 It is more preferable that Next, the above composition will be described.

When the content of SiO ₂ is less than 45% by weight, the chemical durability is deteriorated, and the lead elution amount may increase.
It is preferably at least 49% by weight. On the other hand, if it exceeds 60% by weight, the working temperature range of the glass becomes small, and crystals may be precipitated on the glass and the transparency may be lost. It is preferably at most 57% by weight, more preferably at most 55% by weight. Here, the working temperature range is a value obtained by subtracting the devitrification temperature from the temperature at which the glass viscosity becomes 10 ⁴ poises (the temperature at which the glass forming operation is started). The likelihood of loss of transparency.

Al ₂ O ₃ is not an essential component, but may be contained up to 6% by weight to improve alkali resistance. It is more preferably at least 0.5% by weight. 6% by weight
If the temperature is higher, the softening point becomes too high, and the viscosity increases with a rise in temperature, so that molding may be more difficult. It is more preferably at most 5% by weight, particularly preferably at most 2% by weight.

When the content of Na ₂ O is less than 3% by weight, the softening point becomes too high, and the viscosity increases with a rise in temperature. It is preferably at least 4% by weight, more preferably at least 6% by weight. If it exceeds 11% by weight, the electric resistance decreases. It is preferably at most 10% by weight, more preferably at most 8% by weight.

K ₂ O is used for the purpose of increasing the electric resistance and adjusting the coefficient of thermal expansion by the mixed alkali effect with Na ₂ O.
It is contained in an amount of 3% by weight or more. It is preferably at least 4% by weight, more preferably at least 5% by weight. However, 11% by weight
If it is too large, the coefficient of thermal expansion becomes too high, and there is a possibility that fusion to the neck or frit sealing to the panel cannot be performed. It is preferably at most 10% by weight, more preferably at most 9% by weight.

PbO is an essential component for improving the X-ray absorption function. If the content is less than 5% by weight, the content of BaO, SrO, or the like must be increased in order to obtain a predetermined X-ray absorption function, and the devitrification temperature may increase. It is preferably at least 14% by weight, more preferably at least 15% by weight. If it exceeds 24% by weight, the elution amount of lead may increase. It is preferably at most 21% by weight, more preferably at most 20% by weight.

If the content of SrO exceeds 14% by weight, the devitrification temperature becomes too high, and crystals may precipitate on the glass and the transparency may be lost. It is preferably at most 9% by weight.
If the content of BaO exceeds 21% by weight, the devitrification temperature becomes too high, and crystals may precipitate on the glass and the transparency may be lost. It is preferably at most 11% by weight.

Although CaO is not an essential component, it may be contained up to 5% by weight in order to adjust the softening point. 5% by weight
If the temperature is higher, the softening point becomes too high, and the viscosity increases with a rise in temperature, so that molding may be more difficult. It is more preferably at most 4% by weight.

Although MgO is not an essential component, it may be contained up to 5% by weight in order to adjust the softening point. 5% by weight
If the temperature is higher, the softening point becomes too high, and the viscosity increases with the temperature rise, so that molding may be difficult.
It is more preferably at most 3% by weight.

Although ZnO is not an essential component, the X-ray absorption function is a component having a low but moderate function as compared with PbO. By substituting with PbO, the X-ray absorption function is maintained to some extent, and at the same time, lead is eluted. It has the effect of suppressing the amount.
If it exceeds 2% by weight, the X-ray absorption function may be too low, and X-rays may leak. It is more preferably at most 1% by weight.

Although ZrO ₂ is not an essential component, the X-ray absorption function is a component having a low but moderate function as compared with PbO. It has the effect of suppressing the amount of elution. If it exceeds 4% by weight, the X-ray absorption function is too low, and X-rays may leak. It is more preferably at most 2% by weight. On the other hand, since the X-ray absorption edge wavelength of Zr is shorter than that of Pb, it is more preferable to contain 0.3 wt% or more.
It is more preferably at least 0.4% by weight, particularly preferably at least 0.5% by weight.

TiO ₂ is not an essential component, but 1200
It is a component for adjusting the viscosity of glass at a temperature of not less than ° C. If the content exceeds 0.9% by weight, the working temperature range of the glass becomes small, and crystals may precipitate on the glass and the transparency may be lost. It is more preferably at most 0.7% by weight, particularly preferably at most 0.5% by weight.

Sb ₂ O ₃ is not an essential component, but has a fining effect of reducing bubbles in the molten glass. 1.0% by weight
Above this, the fining effect does not increase, ie the fining effect saturates.

The composition of the glass of the first invention is substantially the same as the above composition.
It is preferred that the object of the present invention be
Other components such as Fe_TwoO_ThreeEtc.
May be. The total amount of the other components is 5% by weight or less.
Is preferred. In addition, As _TwoO_ThreeIs Sb_TwoO_ThreeSame effect as
But may cause environmental problems.
Use is not preferred.

The glass of the second invention has a weight percentage of oxide
Substantially the composition expressed by the _{display, SiO 2 45~60, Al 2 O} 3 0~6, Na 2 O 3~11, K 2 O 3~11, PbO 5~24, SrO 1~14, BaO 1 To 21, CaO 0 to 5, MgO 0 to 5, ZnO 0 to 2, ZrO ₂ 0.3 to 4, TiO ₂ 0 to 0.9, and Sb ₂ O ₃ 0 to 1. Next, the above composition will be described.

When the content of SiO ₂ is less than 45% by weight, the chemical durability is deteriorated, and the lead elution amount may increase.
It is preferably at least 49% by weight. On the other hand, if it exceeds 60% by weight, the working temperature range of the glass becomes small, and crystals may be precipitated on the glass and the transparency may be lost. It is preferably at most 57% by weight, more preferably at most 56% by weight.

If the content of SrO exceeds 14% by weight, the devitrification temperature becomes too high, and crystals may precipitate on the glass and the transparency may be lost. It is preferably at most 9% by weight, more preferably at most 5% by weight. If the content of BaO exceeds 21% by weight, the devitrification temperature becomes too high, and crystals may precipitate on the glass and the transparency may be lost. Preferably 11
% By weight, more preferably 6% by weight or less.

Although CaO is not an essential component, it may be contained up to 5% by weight in order to adjust the softening point. 5% by weight
If the temperature is higher, the softening point becomes too high, and the viscosity increases with a rise in temperature, so that molding may be more difficult. It is more preferably at most 4% by weight, particularly preferably at most 2% by weight.

Al_TwoO_Three, Na_TwoO, K_TwoO, PbO, Mg
O, ZnO, TiO_TwoAnd Sb_TwoO _ThreeAbout the first
The same as the above description of the composition of the glass of the invention,
Omitted.

[0041] The composition of the glass of the second invention it is preferable that consists essentially of the above components, other components within a range not to impair the object of the present invention In addition, for example, it is contained Fe ₂ O _3, etc. Good. The total amount of the other components is preferably 5% by weight or less. Although As ₂ O ₃ has the same effect as Sb ₂ O ₃ , its use is not preferred because it may cause environmental problems.

[0042]

EXAMPLES In the table, columns from SiO ₂ to Sb ₂ O ₃ are shown by weight%.
A mixture of 500 g of glass was prepared using the reagent raw materials so as to obtain the composition indicated by. Next, the prepared raw material was melted at 1500 ° C. using a platinum crucible, stirred at that temperature for 1 hour, homogenized, and then clarified for 1 hour. After fining, the molten glass was poured into a plate having a width of 5 cm, and then gradually cooled.

The lead elution amount A or lead elution amount B was measured as follows. About 5 cut out from the plate-shaped base glass
A sample having a size of about 7 cm and a thickness of about 7 mm was ground and mirror-polished to obtain a sample having a size of about 5 cm and a thickness of about 3 mm. After washing and drying this, a container made of PFA (tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer) (capacity 5
(00 cc, about 8 cm in diameter, about 11 cm in height) in about 100 cc of distilled ion-exchanged water, and immersed at 90 ° C. for 20 hours.

The lead eluted from the sample glass in the distilled ion-exchanged water (immersion liquid) was quantitatively analyzed using IPC seven days after the end of the glass immersion, and this was divided by the surface area of the sample. Was taken as the lead elution amount A. On the other hand, within 30 hours after removing the sample glass from the distilled ion-exchanged water (immersion liquid), 0.3 cc of concentrated nitric acid was added to the immersion liquid. The lead was quantitatively analyzed by IPC, and the result obtained by dividing the result by the surface area of the sample was defined as the lead elution amount B.

The X-ray absorption coefficient (μ value) at a wavelength of 0.06 nm was determined by calculation from the glass composition, the glass density, and the mass absorption coefficient of each component. The softening point and the coefficient of thermal expansion (α) are JIS R3104 and JIS, respectively.
Measured according to R3102.

The devitrification temperature was measured as follows. Each sample was pulverized, glass particles of about 2 to 3 mm were selected, washed and dried, and then placed on a platinum-made porous boat. This platinum porous boat was placed in a temperature gradient furnace at 700 to 1200 ° C. and heat-treated for 48 hours. Then, the platinum porous boat was taken out and allowed to cool. Observing the glass sample in the platinum perforated boat with a polarizing microscope, finding the boundary position between the place where the crystal is deposited on the glass and the transparency is lost and the place where it is not,
The temperature in the electric furnace corresponding to the boundary position was determined, and this was defined as the devitrification temperature.

Table 1 shows the amount of lead elution A (unit: μg / c).
m ² ), lead elution amount B (unit: μg / cm ² ), PbO ratio calculated from the composition in weight% = (PbO content) /
(Total content of PbO, SrO, BaO, CaO, and MgO), μ value (unit: cm ⁻¹ ), softening point (unit: ° C.),
Thermal expansion coefficient α (unit: 10 ^-7 / ° C), devitrification temperature (unit:
° C). Examples 1 to 9 in the table are Examples of the present invention, Example 10
11 are comparative examples. Example 11 is an example of a currently manufactured representative funnel glass (conventional glass).

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

According to the present invention, the amount of lead in the glass which dissolves in water is smaller than that of the conventional glass for a cathode ray tube funnel, and the cathode ray having a high absorption coefficient of X-rays having a wavelength of 0.06 nm. We can provide glass for tube funnel.

Claims (8)

[Claims] When the composition is expressed in terms of weight% on an oxide basis, the content of SrO is 1.0% by weight or more, the content of BaO is 1.0% by weight or more, and the content of PbO is P
A glass for a cathode ray tube funnel having a weight ratio to the total content of bO, SrO, BaO, CaO, and MgO of 0.69 or less, wherein the lead elution amount A of the glass measured by the following method A is 1 0.0 μg / cm ² or less, and the X-ray absorption coefficient at a wavelength of 0.06 nm is 40 cm.
^-1 or more glass for cathode ray tube funnels. (Method A) The glass is immersed in distilled ion-exchanged water at 90 ° C. for 20 hours and then taken out. The amount of lead in the distilled ion-exchanged water is measured by inductively coupled plasma emission spectroscopy, and the measured value of the amount of lead divided by the surface area of the glass is defined as the amount of lead elution A. 2. The composition, expressed in terms of% by weight on an oxide basis, is substantially: SiO ₂ 45-60, Al ₂ O ₃ 0-6, Na ₂ O 3-11, K ₂ O 3-11, PbO. 5-24, SrO 1-14, BaO 1-21, CaO 0-5, MgO 0-5, ZnO 0-2, ZrO ₂ 0-4, TiO ₂ 0-0.9, Sb ₂ O ₃ 0-1 The glass for a cathode ray tube funnel according to claim 1, which is: 3. The composition, expressed in terms of% by weight on an oxide basis, is substantially: SiO ₂ 49-55, Al ₂ O ₃ 0.1-5, Na ₂ O 4-10, K ₂ O 4-10 PbO 15-24, SrO 2-9, BaO 2-11, CaO 0-4, MgO 0-3, ZnO 0-1, ZrO ₂ 0-4, TiO ₂ 0-0.9, Sb ₂ O ₃₀ The glass for a cathode ray tube funnel according to claim 1, wherein 4. The glass for a cathode ray tube funnel according to claim 2, which contains 0.3 to 2.0% by weight of ZrO ₂ . 5. When the composition is expressed in terms of% by weight on an oxide basis, the content of SrO is 1.0% by weight or more, the content of BaO is 1.0% by weight or more, and the content of ZrO ₂ is A glass for a cathode ray tube funnel having an amount of 0.3% by weight or more, the lead elution amount B of the glass measured by the following method B is 4.0 μg / cm ² or less, and a wavelength of 0.0
Glass for a cathode ray tube funnel having an X-ray absorption coefficient at 6 nm of 40 cm ^-1 or more. (Method B) After immersing the glass in distilled ion-exchanged water at 90 ° C. for 20 hours, the glass is taken out. After adding concentrated nitric acid to the distilled ion-exchanged water, the amount of lead is measured by inductively coupled plasma emission spectroscopy, and the measured value of the amount of lead divided by the surface area of the glass is defined as the amount of lead elution B. 6. The composition, expressed in terms of% by weight on an oxide basis, is substantially: SiO ₂ 45-60, Al ₂ O ₃ 0-6, Na ₂ O 3-11, K ₂ O 3-11, PbO. 5~24, SrO 1~14, BaO 1~21, CaO 0~5, MgO 0~5, ZnO 0~2, ZrO 2 0.3~4, TiO 2 0~0.9, Sb 2 O 3 0 The glass for a cathode ray tube funnel according to claim 5, wherein 7. The cathode ray tube funnel according to claim 1, wherein the content of SrO is 1.5% by weight or more, and the content of BaO is 1.5% by weight or more. Glass. 8. The cathode ray tube funnel according to claim 1, wherein the content of SrO is 2.0% by weight or more and the content of BaO is 2.0% by weight or more. Glass.