阅读说明：本技术 玻璃板和其制造方法 (Glass plate and method for producing same ) 是由 土屋博之 黑岩裕 小野和孝 小川朝敬 松尾优作 于 2020-04-07 设计创作，主要内容包括：本发明提供一种新的玻璃板,其可利用于高频器件的基板或窗材料,且高频带下的传播损耗或传输损耗小。所述玻璃板是10GHz的介电损耗角正切为tanδA、玻璃化转变温度为Tg℃的玻璃板,在将使上述玻璃板升温至(Tg+50)℃、接着以100℃/分钟降温至(Tg－150)℃时的介电损耗角正切设为tanδ100时,满足(tanδ100－tanδA)≥0.0004。(The present invention provides a novel glass plate which can be used as a substrate or a window material for a high-frequency device and has a small propagation loss or transmission loss in a high-frequency band. The glass plate is a glass plate having a dielectric loss tangent of tan delta A at 10GHz and a glass transition temperature of Tg, and satisfies (tan delta 100-tan delta A) of not less than 0.0004, when the dielectric loss tangent is tan delta 100 when the glass plate is heated to (Tg +50) DEG C and then cooled to (Tg-150) DEG C at 100 ℃/min.)

1. A glass plate having a dielectric loss tangent of tan delta A and a glass transition temperature of Tg at 10GHz,

(tan delta 100-tan delta A) of not less than 0.0004 is satisfied, where tan delta 100 is a dielectric loss tangent at 10GHz when the glass plate is heated to (Tg +50) ° C and then cooled to (Tg-150) ° C at 100 ℃/min.

2. Glass sheet according to claim 1, wherein the relative dielectric constant at 10GHz is ε rA,

when the relative dielectric constant of 10GHz after the glass plate is heated to (Tg +50) DEG C and then cooled to (Tg-150) DEG C at 100 ℃/min is defined as ε r100, the glass plate satisfies 0.95 ≦ (ε r 100/. epsilon.rA) ≦ 1.05.

3. Glass sheet according to claim 1 or 2, wherein the area of the main face is 350cm²The above.

4. The glass sheet according to any one of claims 1 to 3, wherein the dielectric loss tangent at 10GHz is 0.009 or less.

5. The glass plate according to any one of claims 1 to 4, wherein the relative dielectric constant at 10GHz is 6.8 or less.

6. The glass plate according to any one of claims 1 to 5, wherein the difference in dielectric loss tangent at 10GHz at any two positions separated by 40mm or more is 0.0005 or less.

7. The glass plate according to any one of claims 1 to 6, wherein the difference in relative dielectric constant at 10GHz between any two points separated by 40mm or more is 0.05 or less.

8. The glass plate as claimed in any one of claims 1 to 7, wherein SiO is contained in an amount of 30 to 85% by mole on an oxide basis₂。

9. Glass sheet according to any one of claims 1 to 8, wherein,

contains, expressed in mole percent on an oxide basis:

SiO₂ 57～70％、

Al₂O₃ 5～15％、

B₂O₃ 15～24％、

Al₂O₃+B₂O₃ 20～40％、

Al₂O/(Al₂O₃+B₂O₃) 0.1～0.45、

MgO 0～10％、

CaO 0～10％、

SrO 0～10％、

BaO 0～10％、

Li₂O 0～5％、

Na₂O 0～5％、

K₂o0-5%, and

R₂0-5% of O, wherein R is alkali metal.

10. Glass sheet according to any one of claims 1 to 8, wherein,

contains, expressed in mole percent on an oxide basis:

SiO₂ 55～80％、

Al₂O₃ 0～15％、

SiO₂+Al₂O₃ 55～90％、

B₂O₃ 0～15％、

MgO 0～20％、

CaO 0～20％、

SrO 0～15％、

BaO 0～15％、

MgO+CaO 0～30％、

MgO+CaO+SrO+BaO 0～30％、

Li₂O 0～20％、

Na₂O 0～20％、

K₂0 to 20% of O, and

R₂0-20% of O, wherein R is alkali metal.

11. The glass plate according to any one of claims 1 to 9, which is used for a substrate of a high-frequency device that processes a high-frequency signal of 3.0GHz or higher.

12. Glass sheet according to any of claims 1 to 8 and 10 for use in glazing materials.

13. A method for producing a glass sheet according to any one of claims 1 to 12, comprising the following steps in this order:

a melting and molding step of melting a glass raw material, molding the obtained molten glass into a plate shape,

a temperature lowering step of lowering the temperature of the molten glass formed into a plate shape to a temperature of (Tg-300) DEG C or less with respect to a glass transition temperature Tg (DEG C) to obtain a glass blank plate, and

a heat treatment step of raising the temperature of the obtained glass blank plate from the temperature of (Tg-300) DEG C or lower to a range of (Tg-100) DEG C to (Tg +50) DEG C without exceeding (Tg +50) DEG C and lowering the temperature again to (Tg-300) DEG C or lower;

the heat treatment step is performed 1 or 2 or more times,

the heat treatment step 1 is carried out until the temperature of the glass blank plate exceeds (Tg-300) DEG C, then the glass blank plate passes through the highest temperature Temax DEG C in the range of (Tg-100) DEG C to (Tg +50) DEG C and is below (Tg-300) DEG C again,

the total time during which the temperature of the glass blank sheet is in the range of (Tg-100) DEG C to (Tg +50) DEG C in the entire heat treatment process is K or more represented by the following formula (1) using the maximum temperature Tmax DEG C of the glass blank sheet in the entire heat treatment process, and the unit of K is minutes,

in each of the heat treatment steps, when the time from the last time when the maximum temperature Temax ℃ starts to decrease in temperature to the last time when the temperature reaches (Tg-110) DEG C is t1, the following formula (2) is satisfied, and the unit of t1 is minutes,

k [ { (Tg +50) -Tmax }/10] +15 formula (1)

{ Temax- (Tg-110) }/t 1. ltoreq.10 formula (2).

14. The method for manufacturing a glass sheet as defined in claim 13, wherein the temperature of the glass raw sheet does not exceed (Tg-110) c again after being lowered from the maximum temperature Temax c to below (Tg-110) c for the first time in each of the heat treatment steps.

15. The method for producing a glass sheet as defined in claim 13 or 14, wherein, in each of the heat treatment steps, when any 2 times between the last time when the temperature of the maximum temperature Temax ℃ is decreased and the last time when the temperature of the maximum temperature Temax ℃ is passed through (Tg-110) ° C are t2 and t3, and t2 < t3, the unit of t2 and t3 is minutes,

the difference between the timings of t2 and t3 is 1 minute or more,

when the temperature of the glass raw plate at t2 is Te2 and the temperature of the glass raw plate at t3 is Te3, the following formula (3) is satisfied,

(Te 2-Te 3)/(t 3-t 2) is less than or equal to 10, formula (3).

16. The method for producing a glass sheet as defined in any of claims 13 to 15, wherein an average cooling rate from (Tg +50) ° c to (Tg-100) ° c in the cooling step exceeds 10 ℃/min.

17. The method for producing a glass sheet as defined in any of claims 13 to 16, wherein an average cooling rate in the cooling step is 10 to 1000 ℃/min.

Technical Field

The present invention relates to a glass sheet and a method for producing the same.

Background

Devices that utilize radio waves (hereinafter referred to as "radio wave-utilizing devices") such as radars and mobile phones are used on a daily basis indoors in vehicles and buildings, such as automobiles. In particular, recently, radio wave utilization devices using radio waves in a high frequency band (microwave to millimeter wave), more specifically, a gigahertz band, for example, 3 to 300GHz region, have been actively developed.

As a circuit board used for such radio wave-utilizing devices for high frequency applications (hereinafter referred to as "high frequency devices"), an insulating substrate such as a resin substrate, a ceramic substrate, or a glass substrate is generally used. In order to ensure characteristics such as quality and strength of a high-frequency signal, it is required to reduce transmission loss due to dielectric loss, conductor loss, and the like in an insulating substrate used in a high-frequency device.

On the other hand, glass sheets used as window materials for vehicles such as automobiles and buildings are required to have high visible light transmittance, high ultraviolet and solar shielding performance, and good visual appearance. Patent document 1 discloses an ultraviolet and infrared absorbing glass made of soda-lime-silica glass having a specific composition.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2002-348143

Disclosure of Invention

However, in view of the fact that millimeter-wave radars are mounted in vehicles such as automobiles and electronic devices are used in buildings, glass plates used as window materials for these are also required to reduce propagation loss and transmission loss in the same manner as insulating substrates for high-frequency devices.

Accordingly, an object of the present invention is to provide a novel glass plate which can be used as a substrate and a window material for a high-frequency device and has a small propagation loss and a small transmission loss in a high-frequency band, and a method for manufacturing the same.

The present invention relates to the following.

1. A glass plate having a dielectric loss tangent of tan delta A and a glass transition temperature of Tg at 10GHz,

(tan. delta.100-tan. delta.A) ≥ 0.0004 is satisfied where tan. delta.100 is a dielectric loss tangent at 10GHz when the glass plate is heated to (Tg +50) ° C and then cooled to (Tg-150) ° C at 100 ℃/min.

2. The glass plate according to 1 above, wherein the relative dielectric constant at 10GHz is ε rA,

when the relative dielectric constant of 10GHz after the glass plate is heated to (Tg +50) DEG C and then cooled to (Tg-150) DEG C at 100 ℃/min is made to be epsilon r100, the glass plate satisfies the condition of 0.95 to (epsilon r 100/epsilon rA) to 1.05.

3. The glass plate according to the above 1 or 2, wherein the area of the main surface is 350cm²The above.

4. The glass plate according to any one of the above 1 to 3, wherein a dielectric loss tangent at 10GHz is 0.009 or less.

5. The glass plate according to any one of the above 1 to 4, wherein a relative dielectric constant at 10GHz is 6.8 or less.

6. The glass plate according to any one of the above 1 to 5, wherein a difference in dielectric loss tangent at 10GHz at any two positions separated by 40mm or more is 0.0005 or less.

7. The glass plate according to any one of the above 1 to 6, wherein the difference in relative permittivity at 10GHz between any two points separated by 40mm or more is 0.05 or less.

8. The glass plate as described in any of the above 1 to 7, wherein SiO is contained in an amount of 30 to 85% by mole based on an oxide₂。

9. The glass sheet as claimed in any one of the above 1 to 8,

contains, expressed in mole percent on an oxide basis:

SiO₂ 57～70％，

Al₂O₃ 5～15％，

B₂O₃ 15～24％，

Al₂O₃+B₂O₃ 20～40％，

Al₂O/(Al₂O₃+B₂O₃)0.1～0.45，

MgO 0～10％，

CaO 0～10％，

SrO 0～10％，

BaO 0～10％，

Li₂O 0～5％，

Na₂O 0～5％，

K₂o0 to 5%, and

R₂0 to 5% of O (R ═ alkali metal).

10. The glass sheet as claimed in any one of the above 1 to 8,

contains, expressed in mole percent on an oxide basis:

SiO₂ 55～80％，

Al₂O₃ 0～15％，

SiO₂+Al₂O₃ 55～90％，

B₂O₃ 0～15％，

MgO 0～20％，

CaO 0～20％，

SrO 0～15％，

BaO 0～15％，

MgO+CaO 0～30％，

MgO+CaO+SrO+BaO 0～30％，

Li₂O 0～20％，

Na₂O 0～20％，

K₂o0 to 20%, and

R₂0 to 20% of O (R ═ alkali metal).

11. The glass plate according to any one of the above 1 to 9, which is used for a substrate of a high-frequency device for processing a high-frequency signal of 3.0GHz or higher.

12. The glass sheet according to any one of the above items 1 to 8 and 10, which is used for a window material.

13. A method for producing a glass sheet as defined in any one of 1 to 12 above, comprising the steps of:

a melting and molding step of melting a glass raw material, molding the obtained molten glass into a plate shape,

a temperature lowering step of lowering the temperature of the molten glass formed into a plate shape to a temperature of (Tg-300) DEG C or less with respect to the glass transition temperature Tg (DEG C) to obtain a glass blank plate, and

a heat treatment step of raising the temperature of the obtained glass blank plate from the temperature of (Tg-300) DEG C or lower to a range of (Tg-100) DEG C to (Tg +50) DEG C without exceeding (Tg +50) DEG C and lowering the temperature again to (Tg-300) DEG C or lower;

the above heat treatment step is carried out 1 or 2 or more times,

the heat treatment step 1 time is a step in which the temperature of the glass blank plate exceeds (Tg-300) DEG C, and then passes through a maximum temperature Temax DEG C in the range of (Tg-100) DEG C to (Tg +50) DEG C until the temperature of the glass blank plate becomes (Tg-300) DEG C again or less,

the total time during which the temperature of the glass blank sheet is in the range of (Tg-100) DEG C to (Tg +50) DEG C in the entire heat treatment step is K (minutes) or more represented by the following formula (1) using the maximum temperature Tmax DEG C of the glass blank sheet in the entire heat treatment step,

in each of the heat treatment steps, the time from the last time when the temperature of the maximum temperature Temax ℃ is lowered to the last time when the temperature of (Tg-110) DEG C is passed is t1 (minutes), and the following formula (2) is satisfied.

K [ { (Tg +50) -Tmax }/10] +15 formula (1)

{ Temax- (Tg-110) }/t1 ≦ 10 formula (2)

14. The method for manufacturing a glass sheet as described in claim 13, wherein the temperature of the glass blank sheet is lowered from the maximum temperature Temax ℃ to below (Tg-110) ℃ for the first time in each of the heat treatment steps, and then does not exceed (Tg-110) ℃ again.

15. The method for producing a glass sheet as described in 13 or 14, wherein in each of the heat treatment steps, when any 2 times between the last time when the temperature of the maximum temperature Temax ℃ is decreased and the last time when the temperature of the maximum temperature Temax ℃ is decreased to (Tg-110) ° C are t2 (min), t3 (min), and t2 < t3,

the difference between the times of t2 and t3 is 1 minute or more,

when the temperature of the glass raw plate at t2 is Te2 and the temperature of the glass raw plate at t3 is Te3, the following formula (3) is satisfied.

(Te 2-Te 3)/(t 3-t 2) is less than or equal to 10 formula (3)

16. The method for producing a glass sheet as defined in any of claims 13 to 15, wherein an average cooling rate from (Tg +50) DEG C to (Tg-100) DEG C in the cooling step exceeds 10 ℃/min.

17. The method for producing a glass sheet as defined in any of claims 13 to 16, wherein an average cooling rate in the cooling step is 10 to 1000 ℃/min.

According to the glass plate of the present invention, the absorption of high-frequency electromagnetic waves is small, and high transmittance can be achieved. By using such a glass plate for a circuit board, a practical high-frequency device such as an electronic device, etc., with reduced propagation loss and transmission loss can be provided. Further, when the glass plate is used for windows of vehicles such as automobiles and buildings, electromagnetic waves can be propagated without significant attenuation when millimeter-wave radars are mounted in the vehicles or when electronic devices are used in the buildings.

Detailed Description

The present invention will be described in detail below, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented within a range not departing from the gist of the present invention. "to" indicating a numerical range is used to include numerical values described before and after the range as a lower limit value and an upper limit value. Unless otherwise specified, "%" indicating the composition of the glass plate is a value represented by a mole percentage based on oxides.

< glass plate >

The glass plate of the present embodiment satisfies the relationship of (tan. delta.100-tan. delta.A) ≥ 0.0004, where tan. delta.100 is a dielectric loss tangent at 10GHz, the glass transition temperature is Tg, and the dielectric loss tangent at the time of raising the temperature of the glass plate to (Tg +50) ° C and then lowering the temperature to (Tg-150) ° C at 100 ℃/min is tan. delta.100.

The dielectric loss tangent (hereinafter, may be abbreviated as "tan. delta.") of a glass plate is a value represented by ε "/ε', which is a relative dielectric constant, and ε" is a dielectric loss. As the value of tan δ is smaller, absorption of electromagnetic waves in the frequency band is smaller, and high transmittance can be achieved.

In the present specification, the dielectric loss tangent and the relative permittivity are values measured by the method specified in IEC61189-2-721(2015) with the measurement frequency of 10 GHz.

Generally, the value of tan δ can be adjusted by varying the glass composition. However, the present inventors have found a method capable of adjusting the value of tan δ without changing the glass composition. Thus, even with the same composition, a glass having a smaller tan δ value than conventional glasses can be obtained.

When glass is produced, glass having different densities can be obtained by changing the cooling rate. Specifically, if the cooling rate is high, the glass state becomes low density (thick), and if the cooling rate is low, the glass state becomes high density (dense). The density in the glass state is related to the value of tan δ in the high frequency band.

That is, if the density of the glass state is high and dense, the transmittance of electromagnetic waves in a high frequency band can be improved (absorption is reduced), and the value of tan δ in the high frequency band becomes small. The high frequency band in this specification is usually 3.0GHz or more, particularly 3.5GHz or more, and the actual verification is performed at 10 GHz.

The glass plate of the present embodiment has a smaller value of tan δ a at a high frequency band than a conventional glass plate having the same composition. This can be judged by the above-mentioned value of (tan. delta.100-tan. delta.A). That is, if the value of tan δ 100 when a glass plate having a dielectric loss tangent of tan δ A of 10GHz is heated to (Tg +50) ° C and then cooled to (Tg-150) ° C at 100 ℃/min is larger than the value of tan δ A [ (tan δ 100-tan δ A) > 0], the glass plate obtained at a cooling rate of less than 100 ℃/min has a high density and exhibits high permeability.

Further, by satisfying the relationship that the value of (tan δ 100-tan δ a) is 0.0004 or more [ (tan δ 100-tan δ a) ≥ 0.0004], it can be said that the value of tan δ a is sufficiently smaller than that of a conventional glass plate having the same composition, and exhibits high permeability to electromagnetic waves in a high frequency band.

In this manner, the tan δ A of the glass sheet may satisfy the relationship of (tan δ 100-tan δ A) ≥ 0.0004, but in order to exhibit further high permeability, (tan δ 100-tan δ A) ≥ 0.0005 is preferable, and (tan δ 100-tan δ A) ≥ 0.0006 is more preferable.

The upper limit of (tan. delta.100-tan. delta.A) is not particularly limited, but for the purpose of shortening the heat treatment time and improving the productivity, it may be (tan. delta.100-tan. delta.A) ≦ 0.001, or (tan. delta.100-tan. delta.A) ≦ 0.0008, or (tan. delta.100-tan. delta.A) ≦ 0.0007, or (tan. delta.100-tan. delta.A) ≦ 0.0006.

The difference in dielectric loss tangent tan δ of 10GHz at any two locations of the glass plates spaced apart by 40mm or more is preferably 0.0005 or less, more preferably 0.0004 or less, and still more preferably 0.0003 or less. When the difference in dielectric loss tangent tan δ is 0.0005 or less, the in-plane distribution of the dielectric loss tangent is small, and it can be said that the glass plate is homogeneous without temperature decrease unevenness, and therefore, the glass plate is preferable. Here, "two arbitrary places spaced by 40mm or more" means two arbitrary places spaced by 40mm or more on the same plane.

The lower limit of the difference in dielectric loss tangent tan δ of 10GHz at any two locations spaced apart by 40mm or more on the glass plate is not particularly limited, and may be 0.0001 or more.

When the relative dielectric constant at 10GHz when the glass sheet is heated to (Tg + 50). degree.C.and then cooled to (Tg-150). degree.C.at 100 ℃/min is defined as ε r100, the relative dielectric constant ε rA at 10GHz of the glass sheet preferably satisfies the relationship of 0.95. ltoreq. (. epsilon.r 100/. epsilon.rA). ltoreq.1.05, and the value represented by (. epsilon.r 100/. epsilon.rA) is more preferably 0.98 or more, and still more preferably 0.99 or more. Further, it is more preferably 1.03 or less, still more preferably 1.02 or less, and particularly preferably 1.01 or less.

Unlike the value of tan δ a, the relative dielectric constant ∈ r of the obtained glass sheet can be made substantially constant even if the temperature decrease rate in the production of the glass sheet is changed. Therefore, the loss of the device can be reduced without greatly changing the design of the high-frequency device.

The difference in relative permittivity ε rA at 10GHz between any two locations spaced apart by 40mm or more in the glass plate is preferably 0.05 or less, more preferably 0.04 or less, and still more preferably 0.03 or less. When the difference in relative permittivity ε rA is 0.05 or less, the in-plane distribution of relative permittivity becomes small, and it is preferable that the glass plate be homogeneous without temperature decrease unevenness. The lower limit of the difference in relative permittivity ε rA at 10GHz between any two locations spaced apart by 40mm or more in the glass plate is not particularly limited, and may be 0.01 or more.

The glass plate having such characteristics can be preferably used as a substrate or a window material of a high-frequency device, and a high-frequency device which processes a high-frequency signal of 3.0GHz or more, particularly 3.5GHz or more is more preferable.

The glass plate preferably contains 30 to 85% of SiO in terms of mole percentage based on oxides₂. Alkali-free glass is more preferable as the substrate for high-frequency devices, and soda-lime glass is more preferable as the window material.

Specific preferred glass compositions for each application are as follows.

When the glass plate is used as a substrate of a high-frequency device, the following composition is more preferable as expressed by mole percentage based on oxide.

SiO₂ 57～70％

Al₂O₃ 5～15％

B₂O₃ 15～24％

Al₂O₃+B₂O₃ 20～40％

Al₂O/(Al₂O₃+B₂O₃)0.1～0.45

MgO 0～10％

CaO 0～10％

SrO 0～10％

BaO 0～10％

Li₂O 0～5％

Na₂O 0～5％

K₂0 to 5% of O, and

R₂0 to 5% of O (R ═ alkali metal element)

Hereinafter, each composition will be described.

SiO₂The network-forming substance is preferably contained in an amount of 57% or more because it can improve glass-forming ability and weather resistance and can suppress devitrification. SiO 2₂The content of (b) is more preferably 58% or more, still more preferably 60% or more, and still more preferably 61% or more. In addition, if SiO₂The content of (b) is preferably 70% or less because the meltability of the glass can be improved. The content thereof is more preferably 68% or less, still more preferably 66% or less, still more preferably 65% or less, particularly preferably 64% or less, and most preferably 63% or less.

Al₂O₃Is a component which exhibits effects such as improvement in weather resistance, improvement in Young's modulus, suppression of phase separation of glass, and reduction in thermal expansion coefficient. If Al is present₂O₃When the content of (B) is 5% or more, Al content can be sufficiently obtained₂O₃The effects of (1) are thus preferable. Al (Al)₂O₃The content of (b) is more preferably 6% or more, still more preferably 7% or more, and still more preferably 8% or more. In addition, if Al is present₂O₃The content of (b) is preferably 15% or less because the glass has good melting property and the like. The content thereof is more preferably 14% or less, still more preferably 13% or less, and still more preferably 12% or less.

B₂O₃Is a component for improving the meltability, and the content thereof is preferably 15% or more. Since this component is also a component capable of reducing the dielectric loss tangent in the high frequency region, the content thereof is more preferably 16% or more, still more preferably 17% or more, and still more preferably 17.5% or more. On the other hand, from the viewpoint of obtaining good chemical resistance, B is₂O₃The content of (b) is preferably 24% or less, more preferably 23% or less, and further preferably 22% or less.

From the viewpoint of the melting property of the glass, Al₂O₃And B₂O₃Total content of (Al)₂O₃+B₂O₃) More preferably 20% or more, and particularly preferably 25% or more. In addition, from the viewpoint of improving the low dielectric loss properties of the glass sheet while maintaining the melting properties of the glass, the total content is preferably 40% or less, more preferably 37% or less, still more preferably 35% or less, and particularly preferably 33% or less.

MgO is a component that increases the young's modulus without increasing the specific gravity, and can increase the specific elastic modulus, thereby reducing the problem of deflection, increasing the fracture toughness value, and improving the glass strength. Further, MgO is also a component for improving the melting property, and can suppress the thermal expansion coefficient from becoming too low. It may not contain MgO, but when MgO is contained, it is preferably 0.1% or more, more preferably 0.2% or more, further preferably 1% or more, and further preferably 2% or more. From the viewpoint of suppressing the devitrification temperature increase, the content of MgO is preferably 10% or less, more preferably 9% or less, further preferably 8% or less, further preferably 7% or less, further preferably 6% or less, particularly preferably 5% or less, particularly preferably 4% or less, and most preferably 3% or less.

CaO is a component which has a characteristic of increasing the specific elastic modulus next to MgO in alkaline earth metals without excessively lowering the strain point, and also improves the meltability in the same manner as MgO. Further, this component is also characterized in that the devitrification temperature is less likely to be increased than that of MgO. CaO may not be contained, but when CaO is contained, it is preferably 0.1% or more, more preferably 0.2% or more, further preferably 0.5% or more, further preferably 1% or more, and particularly preferably 2% or more. The content thereof is preferably 10% or less, more preferably 8% or less, further preferably 7% or less, further preferably 6% or less, further preferably 5% or less, particularly preferably 4% or less, and particularly preferably 3% or less, from the viewpoint of preventing devitrification during glass production without increasing the average thermal expansion coefficient excessively and suppressing an increase in devitrification temperature.

SrO is a component that improves the meltability of the glass without increasing the devitrification temperature of the glass. SrO may not be contained, but when SrO is contained, it is preferably 0.1% or more, more preferably 0.2% or more, further preferably 0.5% or more, further preferably 1% or more, and particularly preferably 2% or more. In addition, from the viewpoint of preventing the specific gravity from becoming too large and also suppressing the average thermal expansion coefficient from becoming too high, the content thereof is preferably 10% or less, more preferably 9% or less, still more preferably 8% or less, still more preferably 7% or less, still more preferably 6% or less, particularly preferably 5% or less, particularly preferably 4% or less, particularly preferably 3% or less, and most preferably 2.5% or less.

BaO is a component which does not increase the devitrification temperature of the glass and improves the meltability. BaO may not be contained, but when BaO is contained, it is preferably 0.1% or more, more preferably 0.2% or more, further preferably 1% or more, and particularly preferably 2% or more. The content is preferably 10% or less, more preferably 8% or less, further preferably 5% or less, and further preferably 3% or less, from the viewpoint of increasing the specific gravity, decreasing the young's modulus, increasing the relative permittivity, and excessively increasing the average thermal expansion coefficient.

ZnO is a component for improving chemical resistance, but may be easily separated into phases and may increase the devitrification temperature. Therefore, the content of ZnO is preferably 0.1% or less, more preferably 0.05% or less, even more preferably 0.03% or less, even more preferably 0.01% or less, and particularly preferably substantially not contained. Substantially no ZnO means, for example, less than 0.01%.

From the viewpoint of improving acid resistance and suppressing phase separation to obtain a glass having excellent uniformity, { Al }₂O₃/(Al₂O₃+B₂O₃) The molar ratio is preferably 0.1 or more. Further, from the viewpoint of enhancing the young's modulus, the molar ratio is more preferably 0.3 or more, still more preferably 0.33 or more, still more preferably 0.35 or more, and particularly preferably 0.38 or more. In addition, the molar ratio is preferably 0.45 or less, more preferably 0.4 or less, further preferably 0.35 or less, and further preferably 0.3 or less, from the viewpoint of reducing the dielectric loss in a high frequency region of 10GHz or more, preferably more than 30 GHz.

Mixing Al₂O₃The contents of MgO, CaO, SrO and BaO are respectively set as [ Al ] and [ CaO ], [ SrO ] and [ BaO ] respectively₂O₃]、[MgO]、[CaO]、[SrO]、[BaO]From the aspect of acid resistance, the alloy is composed of { [ Al ]₂O₃]－([MgO]+[CaO]+[SrO]+[BaO]) The value represented by (b) is preferably more than-3, more preferably-2 or more, still more preferably-1 or more, and particularly preferably-0.5 or more. In addition, from the viewpoint of suppressing devitrification of the glass, the glass is composed of { [ Al ]₂O₃]－([MgO]+[CaO]+[SrO]+[BaO]) The value represented by (i) is preferably less than 2, more preferably 1.5 or less, still more preferably 1.0 or less, and particularly preferably 0.5 or less.

From the viewpoint of lowering the surface devitrification temperature and improving the glass productivity, the content molar ratio represented by { (SrO + BaO)/RO } is preferably 0.64 or more, more preferably 0.7 or more, further preferably 0.75 or more, and particularly preferably 0.8 or more. Since raw materials of SrO and BaO are expensive, the molar ratio is preferably 0.85 or less, and more preferably 0.8 or less, from the viewpoint of reducing the raw material price. Here, RO represents the total amount of MgO, CaO, SrO, and BaO.

R₂O represents the total amount of alkali metal oxide. Examples of the alkali metal oxide include Li₂O、Na₂O、K₂O、Rb₂O、Cs₂And O. Due to the inclusion of Rb in the alkali metal oxide in the glass₂O、Cs₂O is rare, so R₂O is usually Li₂O、Na₂O and K₂Total content of O (Li)₂O+Na₂O+K₂O)。

The glass sheet may contain no alkali metal oxide, and when the glass sheet contains an alkali metal oxide, excessive raw material purification is not required, whereby the glass sheet can be practically melted and the glass sheet can be produced with high productivity, and the thermal expansion coefficient of the glass sheet can be adjusted. Therefore, when the alkali metal oxide is contained, the total (R) thereof₂O) content is preferably 0.001% or more, more preferably 0.002% or more, further preferably 0.003% or more, and particularly preferably 0.005% or more. From the viewpoint of improving the low dielectric loss of the glass sheet, the total content thereof is preferably 5% or less, more preferably 3% or less, further preferably 1% or less, further preferably 0.2% or less, further preferably 0.1% or less, and particularly preferably 0.05% or less.

As alkali metal oxides, Li₂The content of O is preferably 0 to 5%, more preferably 0.1% or more, further preferably 0.2% or more, and further preferably 4% or less, further preferably 3% or less. Na (Na)₂The content of O is preferably 0 to 5%, more preferably 0.1% or more, further preferably 0.2% or more, and further preferably 4% or less, further preferably 3% or less. K₂The content of O is preferably 0 to 5%, more preferably 0.1% or more, further preferably 0.2% or more, further preferably 4% or less, and further preferablyIs 3% or less.

In addition to the above, Fe may be contained in order to reduce the resistance value in the melting temperature region, for example, the resistance value of 1500 ℃. When Fe is contained, it is expressed as Fe₂O₃The conversion is preferably 0.01% or more, and more preferably 0.05% or more. However, if the Fe content is too large, the transmittance in the visible region may decrease, and therefore the Fe content may be Fe₂O₃The conversion is preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.1% or less.

The beta-OH value as an index of the water content in the glass is preferably 0.05mm in view of the low resistance value in the temperature range in which the glass raw material is melted, for example, around 1500 ℃ and the suitability for melting the glass by electric heating^-1Above, more preferably 0.1mm^-1Above, more preferably 0.2mm^-1Above, particularly preferably 0.3mm^-1The above. In addition, the beta-OH value is preferably 1.0mm from the viewpoint of reducing bubble defects in the glass^-1Hereinafter, more preferably 0.8mm^-1Hereinafter, more preferably 0.6mm^-1The thickness is preferably 0.5mm or less^-1The following.

In the present specification, the β -OH value is a maximum value β of absorbance measured by measuring the absorbance of a glass sample for light having a wavelength of 2.75 to 2.95 μm_maxDivided by the thickness (mm) of the sample.

In order to improve the fining of the glass sheet, it may contain SnO selected from the group₂Cl and SO₃At least one component of (a). Mixing SiO₂、Al₂O₃、RO、R₂Total content of O (SiO)₂+Al₂O₃+RO+R₂O) is 100% in terms of mass percentage based on oxides, and the total content (SnO)₂+Cl+SO₃) The content of the inorganic filler may be 0.01 to 1.0 mass% in terms of mass percentage. The total content is preferably 0.80% by mass or less, more preferably 0.50% by mass or less, and still more preferably 0.30% by mass or less. The total content is preferably 0.02 mass% or more, more preferably 0.05 mass% or more, and still more preferablyIs 0.10 mass% or more.

In order to improve the acid resistance of the glass, Sc may be contained₂O₃、TiO₂、ZnO₂、Ga₂O₃、GeO₂、Y₂O₃、ZrO₂、Nb₂O₅、In₂O₃、TeO₂、HfO₂、Ta₂O₅、WO₃、Bi₂O₃、La₂O₃、Gd₂O₃、Yb₂O₃And Lu₂O₃At least one component (hereinafter, referred to as "minor component"). However, if the content of the minor constituent is too large, the homogeneity of the glass is lowered and phase separation is likely to occur, and therefore the total content of the minor constituents is 1.0% or less in terms of the molar percentage based on the oxide. The composition may contain only 1 kind of the above-mentioned minor components, or may contain 2 or more kinds.

F may be contained for the purpose of improving the melting property, lowering the strain point, lowering the glass transition temperature, lowering the annealing point, and the like. However, in order to prevent a large number of bubble defects in glass, SiO is used₂、Al₂O₃、RO、R₂Total content of O (SiO)₂+Al₂O₃+RO+R₂O) is preferably 1 mass% or less in terms of mass percentage, when represented as 100 mass% based on the oxide.

When the glass sheet is used as a window material, the following composition is more preferable as expressed in terms of mole percentage based on oxides.

SiO₂ 55～80％

Al₂O₃ 0～15％

SiO₂+Al₂O₃ 55～90％

B₂O₃ 0～15％

MgO 0～20％

CaO 0～20％

SrO 0～15％

BaO 0～15％

MgO+CaO 0～30％

MgO+CaO+SrO+BaO 0～30％

Li₂O 0～20％

Na₂O 0～20％

K₂0 to 20% of O, and

R₂0 to 20% of O (R ═ alkali metal element)

Hereinafter, each composition will be described.

SiO₂And Al₂O₃Is a component that contributes to an improvement in young's modulus and thereby easily secures strength required for window materials for architectural and automotive applications.

SiO prevents thermal cracking due to excessive average linear expansion coefficient while ensuring weather resistance₂The content of (b) is preferably 55% or more, more preferably 57% or more, further preferably 60% or more, further preferably 63% or more, further preferably 65% or more, particularly preferably 68% or more, and most preferably 70% or more. In addition, the content is preferably 80% or less, more preferably 78% or less, further preferably 75% or less, and most preferably 74% or less, from the viewpoint of preventing an increase in viscosity at the time of melting of the glass and facilitating production of the glass.

Al₂O₃Is a component which ensures weather resistance and prevents thermal cracking due to an excessively large average linear expansion coefficient. May not contain Al₂O₃But contains Al₂O₃In this case, the content is preferably 0.01% or more, more preferably 0.05% or more, and still more preferably 0.1% or more. Further, the viscosity of the glass was adjusted to 10 to prevent the viscosity from increasing during melting of the glass²The temperature of dPa · s (hereinafter referred to as T2) and the glass viscosity were 10⁴The content of dpas is preferably 15% or less, more preferably 10% or less, further preferably 5% or less, further preferably 1% or less, and particularly preferably 0.5% or less, from the viewpoint of keeping the temperature of dPa · s low (hereinafter referred to as T4) and facilitating the production of glass, and from the viewpoint of improving the radio wave transmission characteristics.

To obtain good radio wave transmittanceSurface starting of SiO₂And Al₂O₃Total content of (SiO)₂+Al₂O₃) Preferably 55 to 90 percent. Further, from the viewpoint of ensuring weather resistance and preventing the average linear expansion coefficient from becoming excessively large, the total content is more preferably 57% or more, still more preferably 60% or more, still more preferably 65% or more, particularly preferably 70% or more, and most preferably 72% or more. In addition, from the viewpoint of keeping T2 and T4 low and facilitating the production of glass, the total content is more preferably 85% or less, still more preferably 80% or less, still more preferably 78% or less, and particularly preferably 75% or less.

B₂O₃Is a component which improves the melting property and glass strength and also improves the radio wave transmittance. On the other hand, this component is a component which easily volatilizes an alkali element during melting and molding and may possibly deteriorate the quality of the glass, and if it is contained excessively, the average linear expansion coefficient becomes small and physical strengthening becomes difficult. Thus, B₂O₃The content of (b) is preferably 15% or less, more preferably 10% or less, further preferably 8% or less, further preferably 5% or less, further preferably 3% or less, particularly preferably 1% or less, and most preferably substantially not contained. Here, the substantial absence means that B is not contained except for the case where B is mixed as an inevitable impurity₂O₃。

MgO promotes melting of the glass raw material and improves weather resistance. On the other hand, from the viewpoint of preventing devitrification and improving the radio wave transmittance, the content of MgO is preferably 20% or less, more preferably 15% or less, further preferably 8% or less, further preferably 4% or less, particularly preferably 1% or less, and most preferably 0.5% or less, or may not be contained.

CaO, SrO, and BaO are components that can reduce the dielectric loss tangent of the glass and also improve the melting property of the glass, and 1 or more of them may be contained.

The content of CaO may be preferably 3% or more, more preferably 6% or more, further preferably 8% or more, further preferably 10% or more, and particularly preferably 11% or more, in the case where CaO is contained, from the viewpoint of reducing the dielectric loss amount of glass, further improving the radio wave transmittance, and also improving the meltability (lowering T2 and T4). The content is preferably 20% or less from the viewpoint of avoiding an increase in the specific gravity of the glass and maintaining low brittleness and strength, and more preferably 15% or less, still more preferably 14% or less, still more preferably 13% or less, and particularly preferably 12% or less from the viewpoint of further low brittleness.

The SrO content is preferably 15% or less, more preferably 8% or less, further preferably 3% or less, further preferably 1% or less, and particularly preferably substantially no SrO, from the viewpoint of avoiding an increase in the specific gravity of the glass and maintaining low brittleness and strength. Here, the substantial absence of SrO means that SrO is not contained except for the case where SrO is mixed as an inevitable impurity.

From the viewpoint of avoiding an increase in the specific gravity of the glass and maintaining low brittleness and strength, the content of BaO is preferably 15% or less, more preferably 5% or less, further preferably 3% or less, further preferably 2% or less, particularly preferably 1% or less, and most preferably substantially no BaO. Here, the substantial absence of BaO means that BaO is not contained except for the case where BaO is mixed as an inevitable impurity.

The total content of MgO, CaO, SrO and BaO (MgO + CaO + SrO + BaO) may be 0% (not included), but is preferably more than 0%, more preferably 0.5% or more, further preferably 5% or more, further preferably 8% or more, particularly preferably 10% or more, and most preferably 11% or more, from the viewpoint of lowering the glass viscosity during production, lowering T2 and T4, and improving the young's modulus. From the viewpoint of improving the weather resistance, the total content is preferably 30% or less, more preferably 17% or less, further preferably 16% or less, further preferably 15% or less, particularly preferably 14% or less, and most preferably 13% or less.

Further, in order to prevent deterioration of the quality of the glass due to devitrification during melting or molding of the glass, the total content of MgO and CaO (MgO + CaO) is preferably 30% or less, more preferably 25% or less, still more preferably 20% or less, still more preferably 15% or less, and particularly preferably 13% or less. The total content may be 0% (not included), but is preferably 1% or more, more preferably 2% or more, further preferably 5% or more, further preferably 8% or more, and particularly preferably 10% or more, from the viewpoint of preventing the viscosity of the glass from becoming too high at the time of melting and molding and making the production difficult.

Li₂O is a component for improving the meltability of the glass, and contributes to the enhancement of the glass strength by increasing the Young's modulus. May not contain Li₂O but by containing Li₂O is chemically strengthened, and is also effective for improving radio wave transmittance in some cases. Therefore, containing Li₂In the case of O, the content is preferably 0.1% or more, more preferably 1% or more, further preferably 2% or more, further preferably 3% or more, and particularly preferably 4% or more. Further, since devitrification or phase separation may occur during glass production, and the production may become difficult, the content thereof is preferably 20% or less, more preferably 16% or less, further preferably 12% or less, further preferably 8% or less, particularly preferably 7% or less, and most preferably 6.5% or less.

Na₂O and K₂O is a component for improving the melting property of the glass, and the content of at least one of O and O is 0.1% or more, whereby T2 can be easily suppressed to 1750 ℃ or less and T4 can be easily suppressed to 1350 ℃ or less. In addition, if Na₂O and K₂When the total content of O is small, the average linear expansion coefficient may not be increased, and heat strengthening may not be performed. Further, by containing Na together₂O and K₂O, which can improve weather resistance while maintaining meltability. Further, it is sometimes effective to improve the radio wave transmittance.

May not contain Na₂O but by containing Na₂Since O can chemically strengthen in addition to the above-described effects, the content thereof is preferably 0.1% or more, more preferably 1% or more, further preferably 3% or more, further preferably 5% or more, and particularly preferably 6% or more. In addition, from the prevention of the mean linear expansion systemThe content is preferably 20% or less, more preferably 16% or less, further preferably 14% or less, further preferably 12% or less, particularly preferably 10% or less, and most preferably 8% or less, from the viewpoint that the number becomes too large and thermal cracking is easily caused.

May not contain K₂O but by containing K₂O is preferably 0.1% or more, more preferably 0.9% or more, further preferably 2% or more, further preferably 3% or more, and particularly preferably 4% or more. In addition, the content is preferably 20% or less, more preferably 16% or less, further preferably 14% or less, further preferably 12% or less, particularly preferably 10% or less, and most preferably 8% or less, from the viewpoint of preventing the average linear expansion coefficient from becoming too large and easily thermally cracked and preventing the weather resistance from being lowered. In view of radio wave transmittance, K is used₂With the content of O in the above range, a high radio wave transmittance can be obtained.

Thus, by reacting Na₂O and K₂O is contained in the above range, and the average thermal expansion coefficient can be adjusted to a desired value, and thus the composition can be suitably used as a window material having good compatibility with other members such as black ceramics and an interlayer film.

R₂O represents the total amount of alkali metal oxide. Inclusion of Rb in alkali metal oxides in glasses₂O、Cs₂The case of O is rare, therefore, R₂O is usually Li₂O、Na₂O and K₂Total content of O (Li)₂O+Na₂O+K₂O)。

The alkali metal oxide may not be contained, but the alkali metal oxide is a component which lowers the viscosity of the glass during glass production and lowers T2 and T4. Therefore, the total content thereof is preferably more than 0%, more preferably 1% or more, further preferably 5% or more, further preferably 6% or more, further preferably 8% or more, particularly preferably 10% or more, particularly preferably 11% or more, and particularly preferably 12% or more. From the viewpoint of improving the weather resistance, the total content is preferably 20% or less, more preferably 19% or less, still more preferably 18.5% or less, still more preferably 18.0% or less, particularly preferably 17.5% or less, and most preferably 17.0% or less.

When the alkali metal oxide is contained, it is preferable to contain Na₂O is (Na) in order to sufficiently obtain the effect of lowering the dielectric loss tangent₂O/R₂O) is more preferably 0.01 or more, and still more preferably 0.98 or less. The molar ratio is more preferably 0.05 or more, still more preferably 0.1 or more, still more preferably 0.2 or more, particularly preferably 0.3 or more, and most preferably 0.4 or more. The molar ratio is more preferably 0.8 or less, still more preferably 0.7 or less, particularly preferably 0.6 or less, and most preferably 0.55 or less.

When the alkali metal oxide is contained, K is preferably contained₂O is (K) from the viewpoint of sufficiently obtaining the effect of improving the radio wave transmittance₂O/R₂O) is more preferably 0.01 or more, and still more preferably 0.98 or less. The molar ratio is more preferably 0.05 or more, still more preferably 0.1 or more, still more preferably 0.2 or more, particularly preferably 0.3 or more, and most preferably 0.4 or more. The molar ratio is more preferably 0.8 or less, still more preferably 0.6 or less, and particularly preferably 0.55 or less.

The total content (R) of the alkali metal oxides in order to improve the radio wave transmittance₂O,%) multiplied by the MgO content (%) (R)₂O×MgO，％²) Preferably reduced. (R)₂O × MgO) is preferably 100%²Below, more preferably 80%²Hereinafter, more preferably 66%²The content of the monomer is preferably 60% or less²The content is preferably 50% or less²The content is preferably 40% or less²Below, most preferably 30%²The following. Further, from the viewpoint of improving the productivity of the glass, it is preferably 1%²Above, more preferably 3%²Above, more preferably 5%²The following.

ZrO₂Is to reduce the viscosity of the glass during meltingAnd (3) a component which promotes melting and improves heat resistance and chemical durability. On the other hand, if the content is too large, the temperature of the liquid phase may rise. Thus, ZrO₂The content of (b) is preferably 5% or less, more preferably 2.5% or less, further preferably 2% or less, more preferably 1% or less, particularly preferably 0.5% or less, and particularly preferably substantially not contained. The term "substantially free" as used herein means that ZrO is not contained except for the case where ZrO is mixed as an inevitable impurity₂。

Among the above components, (SiO) is used for producing a glass plate from an easily available glass raw material and also for easily securing the weather resistance of the glass plate₂+Al₂O+MgO+CaO+SrO+BaO+Li₂O+Na₂O+K₂O) is preferably 85% or more, more preferably 88% or more, further preferably 90% or more, further preferably 92% or more, further preferably 95% or more, particularly preferably 98% or more, and most preferably 99.5% or more. The total content may be 100%, and is more preferably 99.9% or less in view of the addition of a coloring agent, a refining agent, or the like to the glass plate.

In order to improve the fining of the glass sheet, it may contain SnO selected from the group₂Cl and SO₃At least one component of (a). Mixing SiO₂、Al₂O₃、RO、R₂Total content of main component of O (SiO)₂+Al₂O₃+RO+R₂O) is 100% in terms of mass percentage based on oxides, and the total content (SnO)₂+Cl+SO₃) The content of the inorganic filler may be 0.01 to 1.0 mass% in terms of mass percentage. The total content is preferably 0.80% by mass or less, more preferably 0.50% by mass or less, and still more preferably 0.30% by mass or less. The total content is preferably 0.02 mass% or more, more preferably 0.05 mass% or more, and still more preferably 0.10 mass% or more.

Preferred modes of the glass transition temperature Tg, T2, T4, devitrification temperature, young's modulus, acid resistance, alkali resistance, expansion coefficient (average expansion coefficient), strain point, density, plate thickness, and main surface area of the glass plate when the glass plate is used as a substrate for a high-frequency device are as follows.

The glass transition temperature Tg is preferably 580 ℃ or higher, more preferably 600 ℃ or higher, from the viewpoint of preventing deformation of the substrate in the manufacturing process of the high-frequency device. In addition, from the viewpoint of facilitating the production of the glass plate, the temperature is preferably 750 ℃ or lower, and more preferably 720 ℃ or lower. The glass transition temperature Tg is determined in accordance with JIS R3103-3: 2001, measured value.

From the viewpoint of facilitating the production of the glass sheet, T2 is preferably 1950 ℃ or lower, more preferably 1700 ℃ or lower. In addition, from the viewpoint of reducing convection of the molten glass and making it difficult to damage the glass melting equipment, it is preferably 1500 ℃ or higher.

From the viewpoint of protecting the production equipment, T4 is preferably 1350 ℃ or lower, and more preferably 1300 ℃ or lower. In addition, if the amount of heat taken into the molding equipment by the glass is reduced, the amount of heat input into the molding equipment needs to be increased, and from this point of view, 1100 ℃ or higher is preferable.

T2 and T4 are values measured by a rotary high temperature viscometer.

The devitrification temperature is preferably 1350 ℃ or less, more preferably 1300 ℃ or less, from the viewpoint of reducing the temperature of the members of the molding equipment and extending the life of the members at the time of molding the glass sheet. The lower limit of the devitrification temperature is not particularly limited, and may be 1000 ℃ or higher, or 1050 ℃ or higher. The devitrification temperature is an average value of the highest temperature at which crystals are precipitated on the surface and inside of the glass and the lowest temperature at which crystals are not precipitated, which are observed by optical microscope observation of a sample after heat treatment in an electric furnace in which crushed glass particles are placed in a platinum dish and heat-treated for 17 hours at a constant temperature.

The Young's modulus is preferably 50GPa or more, and more preferably 55GPa or more, in view of suppressing the deflection when the glass plate is subjected to a manufacturing process of a high-frequency device. The upper limit of the Young's modulus is not particularly limited, and may be 100GPa or less. The young's modulus is a value measured by an ultrasonic pulse young's modulus measuring apparatus.

Acid resistance means that the glass plate is placed in an aqueous acid solution (6 wt% HNO)₃+5wt％H₂SO₄And 45 ℃ C. when the glass composition was immersed in the solution for 170 seconds, the amount of the glass composition eluted per unit surface area was determined. The amount of elution indicating acid resistance is preferably 0.05g/cm so that the surface is not roughened when the glass surface is cleaned with an acid solution²Hereinafter, more preferably 0.03g/cm²The following. The lower limit of the amount of elution is not particularly limited, and may be 0.001g/cm²The above.

The alkali resistance means the amount of elution of the glass component per unit surface area when the glass sheet is immersed in an aqueous alkali solution (1.2 wt% NaOH, 60 ℃) for 30 minutes. The amount of elution indicating alkali resistance is preferably 0.10g/cm so that the surface is not roughened when the glass surface is washed with an alkaline solution²Hereinafter, more preferably 0.08g/cm²The following. The lower limit of the amount of elution is not particularly limited, and may be 0.001g/cm²The above.

The expansion coefficient is a value of an average thermal expansion coefficient measured by a thermal expansion meter at a temperature range of 50 to 350 ℃. From the viewpoint of more appropriately adjusting the difference in thermal expansion coefficient between the semiconductor package and another member when the semiconductor package is configured as a high-frequency device, the average thermal expansion coefficient is preferably 20 × 10^-7(K^-1) Above, more preferably 25 × 10^-7(K^-1) The above. In addition, the average thermal expansion coefficient is preferably 60 × 10^-7(K^-1) Hereinafter, more preferably 50 × 10^-7(K^-1) The following.

From the viewpoint of heat resistance, the strain point is preferably 500 ℃ or higher, and more preferably 550 ℃ or higher. Further, it is preferably 800 ℃ or lower from the viewpoint of ease of relaxation. The strain point is a value measured according to JIS R3103-2 (2001).

For light weight, the density is preferably 2.8g/cm³The following. The lower limit of the density is not particularly limited, and may be 2.0g/cm²The above. The density is a value measured by the archimedes method.

From the viewpoint of ensuring the strength as a substrate, the plate thickness is preferably 0.05mm or more, more preferably 0.1mm or more, and further preferably 0.3mm or more. From the viewpoint of reduction in thickness, reduction in size, improvement in production efficiency, and the like, it is preferably 2.0mm or less, more preferably 1.5mm or less, still more preferably 1.0mm or less, still more preferably 0.7mm or less, and particularly preferably 0.5mm or less.

When the glass plate is used as a substrate of a high-frequency device, the area of the main surface of the glass plate is preferably 80cm²Above, more preferably 350cm²Above, more preferably 500cm²Above, more preferably 1000cm²Above, more preferably 1500cm²Above, particularly preferably 2000cm in the following order²Above 2500cm²Above 3000cm²Above 4000cm²Above 6000cm²Above 8000cm²Over 12000cm²Above 16000cm²Above 20000cm²Above 25000cm²The above. On the other hand, the area of the main surface of the substrate is preferably 5000000cm²The following. Even in this area, the in-plane distribution of the dielectric loss tangent is small, and the glass plate is homogeneous. Therefore, the present invention can be applied to manufacture of a high-frequency device having a large area and a window for transmitting high frequency, which have not been realized in the past. The area of the main surface of the substrate is more preferably 100000cm²Hereinafter, more preferably 80000cm²More preferably 60000cm²Hereinafter, 50000cm is particularly preferable²Hereinafter, more preferably 40000cm²Hereinafter, 30000cm is most preferable²The following.

Preferred examples of the glass transition temperature Tg, T2, T4, devitrification temperature, young's modulus, acid resistance, alkali resistance, expansion coefficient (average expansion coefficient), strain point, density, sheet thickness, and main surface area of the glass sheet when the glass sheet is used as a window material are as follows. The measurement methods of the respective physical properties are the same as those used for the substrate for a high-frequency device.

From the viewpoint of bending the glass, the glass transition temperature Tg is preferably 500 ℃ or higher, and more preferably 520 ℃ or higher. From the viewpoint of air-cooling reinforcement, the temperature is preferably 620 ℃ or lower, and more preferably 600 ℃ or lower.

From the viewpoint of facilitating the production of the glass sheet, T2 is preferably 1550 ℃ or lower, more preferably 1480 ℃ or lower. Further, from the viewpoint of reducing convection of the molten glass and making it difficult to damage the glass melting equipment, 1250 ℃ or higher is preferable.

From the viewpoint of protecting the production equipment, T4 is preferably 1200 ℃ or lower, and more preferably 1100 ℃ or lower. Further, if the amount of heat taken into the molding equipment by the glass is reduced, the amount of heat input into the molding equipment needs to be increased, and from this point of view, it is preferably 900 ℃ or higher.

The devitrification temperature is preferably 1100 ℃ or lower, and more preferably 1000 ℃ or lower, from the viewpoint of reducing the temperature of the members of the molding equipment and extending the life of the members at the time of molding a glass sheet. The lower limit of the devitrification temperature is not particularly limited, and may be 900 ℃ or higher.

From the viewpoint of suppressing the deflection, the Young's modulus is preferably 50GPa or more, and more preferably 55GPa or more. The upper limit of the Young's modulus is not particularly limited, and may be 100GPa or less.

Regarding the acid resistance, the amount of elution described above is preferably 0.1g/cm in order not to roughen the surface when the glass surface is washed with an acid solution²Hereinafter, more preferably 0.05g/cm²The following. The lower limit of the amount of elution is not particularly limited, and may be 0.001g/cm²The above.

Regarding the alkali resistance, the amount of elution shown above is preferably 0.20g/cm in order to prevent the surface from being roughened when the glass surface is washed with an alkaline solution²Hereinafter, more preferably 0.10g/cm²The following. The lower limit of the amount of elution is not particularly limited, and may be 0.001g/cm²The above.

As the thermal expansion coefficient, the average thermal expansion coefficient in the temperature range of 50 to 350 ℃ is used. The average thermal expansion coefficient is preferably 60 × 10 from the viewpoint of facilitating air-cooling reinforcement^-7(K^-1) Above, more preferably 70 × 10^-7(K^-1) The above. In addition, if the average thermal expansion coefficient is too large,it is preferable from this point of view that it does not suffer thermal shock, and it is 130X 10^-7(K^-1) Hereinafter, it is preferably 110 × 10^-7(K^-1) The following.

From the viewpoint of heat resistance, the strain point is preferably 450 ℃ or higher, more preferably 500 ℃ or higher. Further, from the viewpoint of ease of relaxation, it is preferably 700 ℃ or lower. The strain point is a value measured according to JIS R3103-2 (2001).

When the density is increased, the weight becomes heavy, making handling during transportation difficult, and from this viewpoint, the density is preferably 2.8g/cm³The following. The lower limit of the density is not particularly limited, and may be 2.0g/cm²The above.

From the viewpoint of securing rigidity as a window material, the plate thickness is preferably 1.0mm or more, more preferably 1.5mm or more. Further, from the viewpoint of weight reduction, it is preferably 6.0mm or less, and more preferably 5.0mm or less.

When the glass sheet is used as a window material, the area of the main surface of the glass sheet is preferably 350cm²Above, more preferably 500cm²Above, more preferably 1000cm²Above, more preferably 1500cm²Above, particularly preferably 2000cm in the following order²Above 2500cm²Above 3000cm²Above 4000cm²Above 6000cm²Above 8000cm²Over 12000cm²Above 16000cm²Above 20000cm²Above 25000cm²The above.

On the other hand, the area of the main surface of the window material is usually 6000000cm²The following. Even with such a large area, the in-plane distribution of the dielectric loss tangent is small, and the glass plate is homogeneous. Therefore, the present invention is suitable for manufacturing a high-frequency device having a large area and a window for transmitting high frequency, which has not been realized in the related art. In order to ensure the homogeneity of the glass sheet, it is preferable to control the area of the main surface, and therefore, the area of the main surface of the window material is more preferably 100000cm²Hereinafter, more preferably 80000cm²More preferably 60000cm²Hereinafter, 50000cm is particularly preferable²Hereinafter, more preferably 40000cm²Hereinafter, 30000cm is most preferable²The following.

Both tan delta A and epsilon rA are preferably small. This makes it possible to apply the present invention to a large-area high-frequency device, a window for transmitting high frequency, and the like, which have not been realized in the past. the tan δ a is preferably 0.009 or less, more preferably 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, further preferably 0.004 or less, particularly preferably 0.0035 or less, further preferably 0.003 or less, and most preferably 0.0025 or less in this order.

The lower limit of tan δ a is not particularly limited, but is 0.0001 or more, more preferably 0.0004 or more, further preferably 0.0006 or more, further preferably 0.0008 or more, and most preferably 0.001 or more, from the viewpoint of the availability of glass plate production. Epsilon rA is preferably 6.8 or less, more preferably 6.5 or less, 6.0 or less, 5.5 or less, 5.2 or less, and 4.9 or less in this order, further preferably 4.7 or less, particularly preferably 4.5 or less, further preferably 4.4 or less, and most preferably 4.3 or less.

The lower limit of ∈ rA is not particularly limited, but is 3.5 or more, more preferably 3.6 or more, still more preferably 3.7 or more, particularly preferably 3.8 or more, further preferably 3.9 or more, and most preferably 4.0 or more, from the viewpoint of the availability of glass sheet production.

< method for producing glass plate >

The method for manufacturing a glass plate of the present embodiment includes the following steps in order: a melting and molding step of melting a glass raw material and molding the obtained molten glass into a plate shape; a temperature lowering step of lowering the temperature of the molten glass molded into a plate shape to a temperature of (Tg-300) DEG C or less with respect to a glass transition temperature Tg (DEG C) to obtain a glass blank plate; and a heat treatment step of raising the temperature of the obtained glass blank plate from the temperature of (Tg-300) DEG C or lower to a range of (Tg-100) DEG C to (Tg +50) DEG C without exceeding (Tg +50) DEG C and lowering the temperature again to (Tg-300) DEG C or lower.

The heat treatment step is performed 1, 2 or 3 or more times.

The heat treatment step 1 time is a step in which the temperature of the glass blank plate exceeds (Tg-300) DEG C, and then passes through the maximum temperature Temax DEG C in the range of (Tg-100) DEG C to (Tg +50) DEG C until the temperature of the glass blank plate becomes (Tg-300) DEG C or less again.

In the entire heat treatment step, the total time during which the temperature of the glass blank sheet is in the range of (Tg-100) DEG C to (Tg +50) DEG C is K (minutes) or more represented by the following formula (1) using the maximum temperature Tmax DEG C of the glass blank sheet in the entire heat treatment step.

In each of the heat treatment steps, the time from the last time when the temperature of the maximum temperature Temax ℃ is lowered to the last time when the temperature of (Tg-110) DEG C is passed is t1 (minutes), and the following formula (2) is satisfied.

K [ { (Tg +50) -Tmax }/10] +15 formula (1)

{ Temax- (Tg-110) }/t1 ≦ 10 formula (2)

Thus, the glass plate described in < glass plate > can be obtained.

(melting and Molding Process)

The melting and molding step is a step of melting a glass raw material and molding the obtained molten glass into a sheet shape, and a conventionally known method can be used without particular limitation. An example thereof is shown below.

Glass raw materials are prepared so as to have a target glass plate composition, and the raw materials are continuously charged into a melting furnace, and preferably heated to about 1450 to 1750 ℃ to obtain molten glass.

The raw material may be a halide such as an oxide, a carbonate, a nitrate, a sulfate, a hydroxide, or a chloride. In the case where the step of bringing the molten glass into contact with platinum is present in the melting and refining step, there are cases where minute platinum particles are eluted into the molten glass and mixed as foreign matter into the resulting glass sheet, but the use of the nitrate raw material has an effect of preventing the formation of platinum foreign matter.

As the nitrate, strontium nitrate, barium nitrate, magnesium nitrate, calcium nitrate, or the like can be used. More preferably, strontium nitrate is used. The particle size of the raw material may be suitably from a raw material having a relatively large particle diameter of several hundred μm to such an extent that no melting residue is produced to a raw material that no melting residue is producedA raw material having a relatively small particle diameter of about several μm which is scattered during transportation and does not aggregate into secondary particles. Mitochondria can also be used. The water content of the raw material may be appropriately adjusted to prevent scattering of the raw material. The degree of oxidation-reduction of beta-OH or Fe (redox { Fe) } can also be adjusted appropriately²⁺/(Fe²⁺+Fe³⁺) }) and the like.

Next, a fining process for removing bubbles from the obtained molten glass may be performed. The clarification step may be carried out by defoaming under reduced pressure, or defoaming may be carried out by heating to a temperature higher than the melting temperature of the raw material. As a clarifying agent, SO may be used₃Or SnO₂。

As SO₃A source, preferably a sulfate of at least 1 element selected from the group consisting of Al, Li, Na, K, Mg, Ca, Sr, and Ba. More preferably an alkali metal sulfate, wherein Na₂SO₄The effect of increasing the size of bubbles is remarkable and the initial melting property is good, and therefore, this is particularly preferable. In addition, the sulfate may be a sulfate of an alkaline earth metal, in which CaSO₄·2H₂O、SrSO₄And BaSO₄The effect of increasing the size of bubbles is remarkable, and more preferable.

As the clarifying agent in the defoaming method under reduced pressure, a halogen such as Cl or F is preferably used.

As the Cl source, a chloride of at least 1 element selected from Al, Mg, Ca, Sr and Ba is preferable, and a chloride of an alkaline earth metal is more preferable, wherein SrCl₂·6H₂O and BaCl₂·2H₂O is particularly preferable because it has a remarkable effect of increasing bubbles and is low in deliquescence.

As the F source, a fluoride of at least 1 element selected from the group consisting of Al, Na, K, Mg, Ca, Sr and Ba is preferable, and a fluoride of an alkaline earth metal is more preferable, wherein CaF₂The effect of increasing the meltability of the glass raw material is remarkable, and more preferably.

In SnO₂The tin compound represented by the formula produces O in the glass melt₂A gas. From SnO in molten glass at a temperature of 1450 ℃ or higher₂Reduction to SnO to produce O₂Gas of havingThe effect of enlarging the bubble to grow. When manufacturing a glass plate, the glass raw material is heated to about 1450 to 1750 ℃ for melting, so that bubbles in the molten glass become larger more effectively.

Next, a forming step of forming a molten glass, preferably a molten glass from which bubbles have been removed in a fining step, into a sheet to obtain a glass ribbon is performed.

As the forming step, there can be applied a known method of forming glass into a plate shape, such as a float method of forming a glass ribbon by flowing molten glass onto a molten metal such as tin to form a plate shape, an overflow down-draw method (melting method) of causing molten glass to flow downward from a gutter-shaped member, or a slit down-draw method of causing molten glass to flow downward from a slit.

The molten glass may be directly subjected to the subsequent temperature reduction step without being molded into a plate shape.

(temperature reduction Process)

The molten glass obtained in the molding step is cooled to a temperature of (Tg-300) DEG C or less with respect to the glass transition temperature Tg (DEG C) to obtain a glass blank plate. The average cooling rate in this case is not particularly limited, and any average cooling rate can be used, but for example, from the viewpoint of preventing devitrification of the glass, it is preferably 10 ℃/min or more, and more preferably 40 ℃/min or more. Further, from the viewpoint that no strain is generated in the glass in the temperature lowering step, it is preferably 1000 ℃/min or less, and more preferably 100 ℃/min or less. The average cooling rate from (Tg +50) DEG C to (Tg-100) DEG C is preferably more than 10 ℃/min, and more preferably 15 ℃/min or more.

The average cooling rate is an average value obtained from the refractive index when the cooling rates at the center and the end portions of the glass sheet are different from each other. The cooling rates at the center and the end portions can be measured from the refractive index, respectively.

(Heat treatment Process)

After the temperature reduction step, the obtained glass blank plate is subjected to a heat treatment in which the temperature is increased from the above-mentioned temperature of (Tg-300) or lower to a range of (Tg-100) DEG C to (Tg +50) DEG C and the temperature is reduced to (Tg-300) DEG C or lower without exceeding (Tg +50) DEG C. The heat treatment step may be performed only 1 time, 2 times, or 3 or more times.

The heat treatment step 1 is carried out until the temperature of the glass blank plate exceeds (Tg-300) DEG C, and then the glass blank plate passes through the maximum temperature Temax DEG C in the range of (Tg-100) DEG C to (Tg +50) DEG C until the temperature of the glass blank plate becomes (Tg-300) DEG C or less again.

The rate of temperature increase from the time when the temperature exceeds (Tg-300) ℃ to the time when the temperature reaches the range of (Tg-100) to (Tg +50) ℃ in the 1-time heat treatment step is not particularly limited. The temperature may be raised and lowered repeatedly until the temperature reaches the range of (Tg-100) DEG C to (Tg +50) DEG C, or may be maintained at a constant temperature.

The total time during which the temperature of the glass raw plate is within the range of (Tg-100) DEG C to (Tg +50) DEG C in the entire heat treatment step is K (minutes) or more represented by the following formula (1) using the maximum temperature Tmax DEG C of the glass raw plate in the entire heat treatment step.

K [ { (Tg +50) -Tmax }/10] +15 formula (1)

When the heat treatment step is performed 2 or more times, the total time during which the temperature of the raw glass plate is in the range of (Tg-100) DEG C to (Tg +50) DEG C is the total time of the 1 st heat treatment step and the time of the heat treatment steps after the 2 nd heat treatment step during which the temperature of the raw glass plate is in the range of (Tg-100) DEG C to (Tg +50) DEG C. When the total time for which the temperature of the glass blank is in the range of (Tg-100) DEG C to (Tg +50) DEG C is K (minutes) or more, the radio wave transmittance is improved.

The total time for which the temperature of the glass blank is in the range of (Tg-100) DEG C to (Tg +50) DEG C is preferably (K +5) minutes or more, and more preferably (K +10) minutes or more. The upper limit is not particularly limited, but in order to improve productivity, the time is preferably (K +60) minutes or less, more preferably (K +45) minutes or less, and still more preferably (K +30) minutes or less.

The temperature distribution of the glass blank is not particularly limited as long as the total time in the range of (Tg-100) DEG C to (Tg +50) DEG C is K (minutes) or more. That is, the temperature may be raised to a range of (Tg-100) DEG C to (Tg +50) DEG C during 1 heat treatment step, then lowered to a temperature exceeding (Tg-300) DEG C and below (Tg +50) DEG C, and again raised to a range of (Tg-100) DEG C to (Tg +50) DEG C, and the temperature may be raised and lowered repeatedly. In addition, the temperature may be kept constant.

In order to improve the radio wave transmittance, the lower limit of the temperature range is (Tg-100) deg.C, preferably (Tg-90) deg.C or more, and more preferably (Tg-80) deg.C or more. In order to prevent glass deformation, the upper limit of the temperature range is (Tg +50) deg.C, preferably (Tg +40) deg.C or less, and more preferably (Tg +35) deg.C or less.

In each heat treatment step, the time from the last time when the temperature of the maximum temperature Temax ℃ is lowered to the last time when the temperature of (Tg-110) DEG C is passed is t1 (minutes), and the following formula (2) is satisfied. When the heat treatment step is performed 1 time, the Temax ℃ is the same as the Tmax ℃. When the heat treatment step is performed 2 or more times, the maximum temperature among 2 or more Temax ℃ is the Tmax ℃.

{ Temax- (Tg-110) }/t1 ≦ 10 formula (2)

The temperature distribution of the glass blank plate is varied, and in addition to the above-described case where the temperature is raised to the range of (Tg-100) DEG C to (Tg +50) DEG C, then the temperature is lowered to the temperature exceeding (Tg-300) DEG C and below (Tg +50) DEG C, and then the temperature is raised again to the range of (Tg-100) DEG C to (Tg +50) DEG C, there is a case where the temperature is changed by raising or lowering the temperature in the range of (Tg-100) DEG C to (Tg +50) DEG C, and the temperature is maintained at a constant temperature in the range of (Tg-100) DEG C to (Tg +50) DEG C.

In the various temperature distributions, when the maximum temperature Temax ℃ is reached only once, the last time the temperature is decreased from the maximum temperature Temax ℃ is the time. In addition, when there are two or more times, the time of the last time is referred to. Further, the time when the sample is held at the maximum temperature Temax ℃ for a certain time is the last time the holding is completed.

The same applies to the time point when the temperature finally passes (Tg-110). degree.C. That is, the temperature may be repeatedly raised or lowered after the last time the temperature is lowered from the maximum temperature Temax ℃ to (Tg-300) ° c or lower, or may be maintained at a constant temperature. When the number of passes through (Tg-110) DEG C is 1 while the temperature is lowered to (Tg-300) ° C or lower, the time of the last pass through (Tg-110) ° C is the time of the pass through (Tg-110) ° C. When the temperature is increased again to exceed (Tg-110) DEG C after passing through (Tg-110) DEG C once and the temperature is decreased again, the time point when the temperature is finally decreased passes through (Tg-110) DEG C is referred to. When the sample is held at (Tg-110) ℃ for a certain period of time, this means the last time the holding is completed.

The temperature distribution in the heat treatment step other than the above is not particularly limited.

In each heat treatment step, it is preferable that the temperature of the glass raw plate is lowered from the maximum temperature Temax ℃ to a temperature lower than (Tg-110) ℃ for the first time and then does not exceed (Tg-110) ℃ again, from the viewpoint of shortening the production process.

In each heat treatment step, when t2 (minutes), t3 (minutes), and t2 < t3 are set as 2 times from the last time when the temperature of the maximum temperature Temax ℃ is decreased to the last time when the temperature is decreased to (Tg-110) ° c, the time difference between t2 and t3 is 1 minute or more, the temperature of the glass preform at t2 is Te2, and the temperature of the glass preform at t3 is Te3, the following formula (3) is preferably satisfied.

(Te 2-Te 3)/(t 3-t 2) is less than or equal to 10 formula (3)

In the above equation (3), it is preferable that the temperature decrease rate at the time t1 is not excessively high, and that a sufficient heat treatment time can be secured by satisfying the relationship of the equation (3).

The value represented by (Te 2-Te 3)/(t 3-t 2) is more preferably 9 or less, and still more preferably 8 or less. The lower limit is not particularly limited, and may be 0.1 or more in order to prevent the time required for producing the glass sheet from becoming excessively long.

In the final heat treatment step, when the average cooling rate at the center of the glass raw sheet is VC (DEG C/min) and the average cooling rate at the edge is VE (DEG C/min) when the temperature is reduced from the maximum temperature Temax ℃ to (Tg-300) DEG C or less, the ratio VC/VE is preferably as close to 1 from the viewpoint of the homogeneity of the obtained glass sheet. Specifically, it is preferably 0.8 or more, more preferably 0.9 or more, and further preferably 1.2 or less, more preferably 1.1 or less, and most preferably 1.

The glass plate of the present embodiment is obtained by directly cooling the glass blank plate to (Tg-300) ° c or lower in the heat treatment step to room temperature (for example, to 50 ℃ or lower).

The temperature reduction to room temperature is not particularly limited, and for example, the average temperature reduction rate from (Tg-300) DEG C to 50 ℃ is preferably 0.5 ℃/min or more, and preferably 50 ℃/min or less. Further, natural cooling may be performed without temperature control.

The method for producing a glass plate is not limited to the above embodiment, and variations, improvements, and the like within a range in which the object of the present invention can be achieved are included in the present invention.

For example, when a glass plate is produced, the glass can be formed into a plate shape by a press molding method in which molten glass is directly molded into a plate shape. After the glass sheet is obtained, any treatment or processing such as air-cooling strengthening treatment, chemical strengthening treatment, polishing, and the like may be performed.

In melting and refining of the glass raw material, not only the melting vessel made of refractory material but also a crucible made of platinum or an alloy containing platinum as a main component (hereinafter, referred to as "platinum crucible") may be used as the melting vessel and/or the refining vessel.

In the melting step when a platinum crucible is used, the raw material is prepared so as to have a composition of the glass plate to be obtained, and the platinum crucible containing the raw material is heated, preferably to around 1450 to 1700 ℃. Then, the molten glass was stirred for 1 to 3 hours with a platinum stirrer inserted.

In the forming step in the manufacturing process of a glass plate using a platinum crucible, the molten glass may be made into a plate or block by flowing it onto a carbon plate or into a mold frame, for example.

By using the glass plate thus obtained as a substrate for a high-frequency device, the propagation loss of a high-frequency signal can be reduced, and the characteristics such as the quality and strength of the high-frequency signal can be improved. Therefore, the substrate made of the glass plate can be applied to a high-frequency device that processes a high-frequency signal of 3.0GHz or more, and can also be applied to a high-frequency device that processes a signal of various high-frequency bands having frequencies of 3.5GHz or more, 10GHz or more, 30GHz or more, and 35GHz or more.

The high-frequency device is not particularly limited, and examples thereof include a high-frequency device (electronic device) such as a semiconductor device used in communication equipment such as a mobile phone, a smartphone, a portable information terminal, and a Wi-Fi device, a radar device such as a Surface Acoustic Wave (SAW) device and a radar transceiver, and an antenna device such as a liquid crystal antenna.

In addition to the above, the glass sheet is also suitable as a window material for vehicles such as automobiles and buildings. That is, the high-frequency device that processes the high-frequency signal may be installed in a vehicle, like a millimeter-wave radar. In many cases, the communication device is used in a building like a communication device or a base station. Therefore, it is also very useful to reduce the propagation loss of the high-frequency signal in the above window material.

When a glass plate is used as a window material, the glass plate may be formed into a curved shape by forming the glass plate into a curved shape by gravity molding, press molding, or the like, in addition to a glass plate formed into a flat shape by a float method or a melting method, and may be used by being deformed arbitrarily depending on the installation place.

The glass constituting the glass plate is not particularly limited to soda lime glass, aluminosilicate glass, alkali-free glass, and the like, and may be appropriately selected according to the application. Further, the tempered glass may have a compressive stress layer on the surface of the glass and a tensile stress layer in the glass. As the tempered glass, chemically tempered glass and air-cooled tempered glass (physically tempered glass) can be used.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[ examples 1 to 4]

Glass raw materials having a composition shown as composition 1 in table 1 were charged into a platinum crucible, and heated and melted at 1650 ℃ for 3 hours in an electric furnace to obtain molten glass. During melting, a platinum stirrer was inserted into a platinum crucible and stirred for 1 hour to homogenize the glass. The molten glass is poured onto a carbon plate and formed into a plate shape (melting and forming step).

Thereafter, the plate-like molten glass was placed in an electric furnace at a temperature of about (Tg +50) ° c, held at the temperature for 1 hour, and then cooled to room temperature at an average cooling rate of 1 ℃/minute to obtain a glass blank plate (cooling step).

Subsequently, the temperature was raised to 630 ℃ at 10 ℃ per minute, and the temperature was held at 630 ℃ for the time period described in "holding time (minutes)" in Table 2. Thereafter, the temperature was lowered from 630 ℃ to (Tg-300 ℃) in an electric furnace at an average cooling rate shown in Table 2, and the glass plate was naturally cooled to room temperature (heat treatment step). Examples 1 to 3 are examples, and example 4 is a comparative example.

The physical properties of the obtained glass sheet were measured by the following procedures.

The results are shown in tables 1 and 2 together with the composition. In the table, the blank column of the composition indicates that the additive was not intentionally added, and the blank column of the physical properties indicates that the measurement was not performed.

[ glass transition temperature Tg (. degree. C.) ]

The glass transition temperature was measured using a thermal dilatometer (model TD5000SA, manufactured by MAC Co., Ltd.) in accordance with JIS R3103-3: 2001 were measured.

[T2、T4(℃)]

The viscosity of the glass was measured to calculate T2 and T4. Specifically, the viscosity of the glass was measured by using a rotary high temperature viscometer (manufactured by OPTKIGYO Co., Ltd., RVM-550) according to ASTM C965-96 (2002). As a standard sample, the viscosity of glass was corrected by MIST717a, and T2 and T4 were calculated.

[ devitrification temperature ]

The devitrification temperature was measured by placing the crushed glass particles in a platinum dish, heat-treating the glass particles in an electric furnace controlled at a constant temperature for 17 hours, and observing the heat-treated sample through an optical microscope (model ME600, manufactured by Nikon) to obtain an average value of the maximum temperature at which crystals are precipitated on the surface and inside of the glass and the minimum temperature at which crystals are not precipitated.

[ Young's modulus ]

Young's modulus was measured according to JIS R1602 (1995) using an ultrasonic pulse Young's modulus measuring apparatus (manufactured by Olympus, 38 DL-PAUS).

[ acid resistance ]

For acid resistance, glass samples were placed in aqueous acid (6 wt% HNO)₃+5wt％H₂SO₄45 ℃ C. for 170 seconds, and the amount of elution of the glass component per unit surface area (mg/cm) was evaluated²)。

[ alkali resistance ]

For alkali resistance, a glass sample was immersed in an aqueous alkali solution (1.2 wt% NaOH, 60 ℃) for 30 minutes to evaluate the amount of elution of the glass component per unit surface area (mg/cm)²)。

[ average coefficient of thermal expansion ]

The thermal expansion coefficient was measured at a temperature of 50 to 350 ℃ in accordance with JIS R3102 (1995) using TMA (model TD5000SA, manufactured by MAC). The average value of the linear expansion coefficient at 50 to 350 ℃ is determined as the average thermal expansion coefficient from the results.

[ Strain Point ]

The strain point was measured according to JIS R3103-2 (2001).

[ Density ]

The density was measured according to JIS Z8807 (2012).

[ dielectric loss tangent tan. delta ]

The dielectric loss tangent tan. delta.A at 10GHz of the obtained glass plate was measured by the SPDR method using a 10GHz resonator (product of OWED, 10GHz resonator) in accordance with IEC61189-2-721 (2015).

The dielectric loss tangent tan δ 100 at 10GHz after the glass plate was heated to (Tg +50) ° C and cooled to (Tg-150) ° C at 100 ℃/min was measured in the same manner.

In the table, Δ tan δ represents a value of (tan δ 100-tan δ a).

[ relative dielectric constant ε r ]

The relative dielectric constant ε rA of the obtained glass plate at 10GHz was measured by the SPDR method using a 10GHz resonator (product of OWED, 10GHz resonator) in accordance with IEC61189-2-721 (2015).

The relative dielectric constant ε r100 of 10GHz was measured after the temperature of the glass plate was raised to (Tg +50) ° C and lowered to (Tg-150) ° C at 100 ℃/min.

[ Table 1]

TABLE 1

[ Table 2]

TABLE 2

[ examples 5 to 8]

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 2 in table 1 was used, and the temperature was increased to 597 ℃ at 10 ℃/min, the glass material was held at 597 ℃ for the time shown in "holding time (min)" in table 3, and the temperature was decreased to (Tg-300) ℃ at the average temperature decreasing rate shown in table 3 in the electric furnace in the subsequent heat treatment step. Examples 5 to 7 are examples, and example 8 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 3 together with the composition.

[ Table 3]

TABLE 3

[ examples 9 to 12]

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 3 in table 1 was used, and the temperature was raised to 653 ℃ at 10 ℃/min, the glass material was held at 653 ℃ for the time shown in "holding time (min)" in table 4, and the temperature was lowered to (Tg-300) ℃ in the electric furnace at the average temperature lowering rate shown in table 4. Examples 9 to 11 are examples, and example 12 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 4 together with the composition.

[ Table 4]

TABLE 4

[ examples 13 to 16]

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 4 in table 1 was used, and the temperature was raised to 675 ℃ at 10 ℃/min, the glass material was held at 675 ℃ for the time shown in "holding time (min)" in table 5, and the temperature was lowered to (Tg-300) ℃ at the average temperature lowering rate shown in table 5 in the electric furnace in the subsequent heat treatment step. Examples 13 to 15 are examples, and example 16 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 5 together with the composition.

[ Table 5]

TABLE 5

[ examples 17 to 20]

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 5 in table 1 was used, and the temperature was increased to 760 ℃ at 10 ℃/min, the glass material was held at 760 ℃ for the time shown in "holding time (min)" in table 6, and the temperature was decreased to (Tg-300) ℃ in the electric furnace at the average temperature decreasing rate shown in table 6. Examples 17 to 19 are examples, and example 20 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 6 together with the composition.

[ Table 6]

TABLE 6

Examples 21 to 24

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 6 in table 1 was used, and the temperature was increased to 760 ℃ at 10 ℃/min, the glass material was held at 760 ℃ for the time shown in "holding time (min)" in table 7, and the temperature was decreased to (Tg-300) ℃ in the electric furnace at the average temperature decreasing rate shown in table 7. Examples 21 to 23 are examples, and example 24 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 7 together with the composition.

[ Table 7]

TABLE 7

Examples 25 to 28

A glass plate was obtained in the same manner as in example 1, except that the glass material having the composition shown as composition 7 in table 1 was used, and the temperature was increased to 700 ℃ at 10 ℃/min, the glass material was held at 700 ℃ for the time shown in "holding time (min)" in table 8, and the temperature was decreased to (Tg-300) ℃ at the average temperature decreasing rate shown in table 8 in the electric furnace in the subsequent heat treatment step. Examples 25 to 27 are examples, and example 28 is a comparative example.

The physical properties of the obtained glass plate were measured under the same conditions as in example 1. The results are shown in tables 1 and 8 together with the composition.

[ Table 8]

TABLE 8

[ examples 29 to 31]

A glass material having a composition shown in composition 4 in table 1 was molded into a sheet shape by a glass melting furnace and a molding machine (melting and molding step).

Thereafter, the molten glass formed into a sheet at 700 ℃ was cooled to room temperature by slow cooling equipment at an average cooling rate of 50 ℃/min to obtain a glass raw sheet of 37cm × 47cm and a thickness of 1.1mm (cooling step).

Next, a glass plate was obtained in the same manner as in example 1, except that the temperature was increased to Tmax ℃ in table 9 at 10 ℃/min, the temperature was maintained at Tmax ℃ for the time period indicated in "holding time (min)" in table 9, and the temperature was decreased to (Tg-300) ° c in an electric furnace at the average temperature decrease rate indicated in table 9. Examples 29 to 31 are examples.

When the average cooling rate at the center of the glass blank sheet is VC (c/min) and the average cooling rate at the edge is VE (c/min), the temperature of the electric furnace is adjusted so that the ratio VC/VE becomes 1.1 or less. Here, the end of the glass raw plate means a position 10cm from the end of the glass raw plate.

The relative dielectric constant and the dielectric loss tangent of the obtained glass plate were measured under the same conditions as in example 1, and the approximate center and 4 positions in the vicinity of the angle of the plate were measured, and the maximum value and the minimum value thereof were recorded. The results are shown in Table 9.

In addition, the minimum value of Δ tan δ and the maximum value of ∈ r100/∈ rA are shown in table 9. Table 9 shows the difference between tan δ a at two points where the difference between tan δ a is largest and ∈ rA at two points where the difference between ∈ rA is largest among 4 points near the center and corners of the plate.

[ Table 9]

TABLE 9

Examples 32 to 34

A glass raw material having a composition shown as composition 6 in table 1 was molded into a sheet shape by a glass melting furnace and a molding machine (melting and molding step).

Thereafter, the 800 ℃ plate-like molten glass was cooled to room temperature by slow cooling equipment at an average cooling rate of 800 ℃/min to obtain a glass raw plate of 37cm × 47cm and a thickness of 1.1mm (cooling step).

Next, a glass plate was obtained in the same manner as in example 1, except that the temperature was increased to Tmax ℃ in table 10 at 10 ℃/min, the temperature was maintained at Tmax ℃ for the time indicated in "holding time (minutes)" in table 10, and the temperature was decreased to (Tg-300) ° c in an electric furnace at the average temperature decrease rate indicated in table 10. Examples 32 to 34 are examples.

When the average cooling rate at the center of the glass blank sheet is VC (c/min) and the average cooling rate at the edge is VE (c/min), the temperature of the electric furnace is adjusted so that the ratio VC/VE becomes 1.1 or less. Here, the end of the glass raw plate means a position 10cm from the end of the glass raw plate.

The relative dielectric constant and the dielectric loss tangent of the obtained glass plate were measured under the same conditions as in example 1, and the approximate center and 4 positions in the vicinity of the angle of the plate were measured, and the maximum value and the minimum value thereof were recorded. The results are shown in Table 10.

In addition, the minimum value of Δ tan δ and the maximum value of ∈ r100/∈ rA are shown in table 9. Table 10 shows the difference between tan δ a at two points where the difference between tan δ a is largest and epsilon rA at two points where the difference between epsilon rA is largest among 4 points near the approximate center and corners of the plate.

[ Table 10]

Watch 10

The present invention has been described in detail with reference to the specific embodiments, but it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. It should be noted that the present application is based on japanese patent application filed on 12/4/2019 (japanese patent application 2019-. In addition, all references cited herein are incorporated by reference in their entirety.