Laminated glass

Abstract

One embodiment of the present invention relates to laminated glass having a first glass plate, a second glass plate, and an intermediate film sandwiched between the first glass plate and the second glass plate, wherein: the first glass plate and the second glass plate are borosilicate glass; in the first glass plate and the second glass plate, differences in the content of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, Li2O, Na2O, K2O, and Fe2O3 in the glass component, in terms of oxide by mass%, are all 1.0 mass% or less; the thickness t1 of the first glass plate is 3.0 mm or more; and the thickness t2 of the second glass plate is 1.1 mm or more.

Description

Laminated glass

[0001] The present invention relates to laminated glass.

[0002] From the perspective of carbon neutrality, automotive glass is expected to be lightweight to improve fuel and electricity consumption, and strong to extend the product life cycle. Furthermore, products that are easy to recycle after use are also desired.

[0003] Patent Document 1 discloses laminated glass that combines high strength and thinness, in which the inner glass sheet is chemically strengthened glass having a compressive stress layer on its surface and the outer glass sheet is soda-lime glass, which is physically strengthened glass having a compressive stress layer on its surface. Patent Document 2 discloses laminated glass consisting of a chemically strengthened glass sheet having a thickness ranging from 0.5 mm to 1 mm and a non-chemically strengthened glass sheet having a thickness ranging from 1 mm to 2.5 mm. Patent Document 3 discloses soda-lime laminated glass that includes a first glass sheet disposed on the exterior side and a second glass sheet disposed on the interior side, in which the difference between the annealing point temperature and the softening point temperature of the first glass sheet and the second glass sheet is within ±5°C, the second glass sheet has a thickness of 0.5 mm to 1.8 mm, and the thickness of the first glass sheet is 1.1 to 1.4 times the thickness of the second glass sheet.

[0004] International Publication No. 2017 / 183381 Japanese Patent No. 5890518 Japanese Patent No. 7174262

[0005] The laminated glass described in Patent Document 1 has a problem that the recyclability deteriorates when cullet generated during recycling of the laminated glass is mixed in because the laminated glass is made of laminated glass with different compositions. The laminated glass described in Patent Document 2 has a problem that the outer plates are made of thin, chemically strengthened glass, and are insufficient in durability against sharp flying objects. The laminated glass described in Patent Document 3 has a problem that the glass plates are made of soda-lime silicate glass, and are insufficient in durability against sharp flying objects.

[0006] In view of the above problems, an object of the present invention is to provide a laminated glass that is strong and recyclable.

[0007] The present inventors have discovered that by using borosilicate glass as the glass plates of a laminated glass, reducing the difference in the content of glass components between the glass plates, and setting the thickness of the glass plates to a predetermined value or more, it is possible to provide a high-strength, recyclable laminated glass, and have completed the present invention.

[0008] That is, one embodiment of the present invention is a laminated glass having a first glass plate, a second glass plate, and an interlayer film sandwiched between the first glass plate and the second glass plate, wherein the first glass plate and the second glass plate are borosilicate glass, and the SiO contained in the first glass plate is expressed as mass % on an oxide basis. ２ and the SiO content of the second glass plate ２ the difference between the content of Al and the content of Al contained in the first glass plate is 1.0 mass % or less, ２ O ３ and the Al content of the second glass plate ２ O ３ the difference between the content of B and the content of B contained in the first glass plate is 1.0 mass % or less, ２ O ３ and the content of B contained in the second glass plate ２ O ３ a difference between the content of MgO contained in the first glass plate and the content of MgO contained in the second glass plate is 1.0% by mass or less; a difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 1.0% by mass or less; a difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 1.0% by mass or less; a difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 1.0% by mass or less; ２ The content of O and the Li contained in the second glass plate ２ The difference between the content of Na and the content of O contained in the first glass plate is 1.0 mass % or less, ２ The content of O and the Na content of the second glass plate ２ the difference between the content of K and the content of O is 1.0 mass % or less, and２ The content of O and the content of K in the second glass plate ２ The difference between the content of Fe and O contained in the first glass plate is 1.0 mass % or less, ２ O ３ and the Fe content of the second glass plate ２ O ３ the difference between the content of the first glass sheet and the content of the second glass sheet is 1.0 mass % or less, the thickness t1 of the first glass sheet is 3.0 mm or more, and the thickness t2 of the second glass sheet is 1.1 mm or more.

[0009] According to an embodiment of the present invention, it is possible to provide a laminated glass that is strong and recyclable.

[0010] FIG. 1 is a cross-sectional view of an example of laminated glass according to one embodiment of the present invention.

[0011] Hereinafter, embodiments of the present invention will be described in detail. In the following drawings, components and parts that perform the same function may be denoted by the same reference numerals, and duplicated descriptions may be omitted or simplified. In addition, the embodiments shown in the drawings are schematic in order to clearly explain the present invention, and do not necessarily accurately represent the size or scale of an actual product.

[0012] In this specification, the expression "glass is substantially free of" a certain component means that the glass is free of the component except for unavoidable impurities, and that the component is not actively added. Specifically, this means that the content of each of the components in the glass is 10 ppm by mass or less.

[0013] As shown in FIG. 1 , a laminated glass 10 of this embodiment includes a first glass sheet 11, a second glass sheet 12, and an interlayer film 13 sandwiched between the first glass sheet 11 and the second glass sheet 12. The first glass sheet 11 and the second glass sheet 12 are borosilicate glass, and the SiO content of the first glass sheet 11 is expressed as % by mass on an oxide basis. ２ and the SiO contained in the second glass plate 12 ２ the difference between the content of Al and the content of Al contained in the first glass plate 11 is 1.0 mass % or less, ２ O３ and the Al content of the second glass plate 12 ２ O ３ The difference between the content of B and the content of B contained in the first glass plate 11 is 1.0 mass % or less, ２ O ３ and the content of B contained in the second glass plate 12 ２ O ３ a difference between the content of MgO contained in the first glass plate 11 and the content of MgO contained in the second glass plate 12 is 1.0% by mass or less; a difference between the content of CaO contained in the first glass plate 11 and the content of CaO contained in the second glass plate 12 is 1.0% by mass or less; a difference between the content of SrO contained in the first glass plate 11 and the content of SrO contained in the second glass plate 12 is 1.0% by mass or less; a difference between the content of BaO contained in the first glass plate 11 and the content of BaO contained in the second glass plate 12 is 1.0% by mass or less; ２ The content of O and the Li contained in the second glass plate 12 ２ The difference between the content of Na and the content of O contained in the first glass plate 11 is 1.0 mass % or less. ２ The content of O and the content of Na contained in the second glass plate 12 ２ The difference between the content of K and the content of O is 1.0 mass % or less, and the K contained in the first glass plate 11 ２ The content of O and the content of K contained in the second glass plate 12 ２ The difference between the content of Fe and the content of O contained in the first glass plate 11 is 1.0 mass % or less, ２ O ３ and the Fe content of the second glass plate 12 ２ O ３ is 1.0 mass % or less, the thickness t1 of the first glass plate 11 is 3.0 mm or more, and the thickness t2 of the second glass plate 12 is 1.1 mm or more.

[0014] In the laminated glass of this embodiment, the first glass sheet and the second glass sheet are made of borosilicate glass. The borosilicate glass in the laminated glass of this embodiment is an oxide-based glass containing silicon dioxide as a main component and a boron component. The boron component in the borosilicate glass is boron oxide (diboron trioxide (B ２ O ３ The proportion of boron oxide in glass is B ２ O ３ The glass composition of the borosilicate glass in the first glass sheet and the second glass sheet will be described later. In the laminated glass of this embodiment, the first glass sheet and the second glass sheet are made of borosilicate glass, so that the durability of the laminated glass can be improved while suppressing increases in fuel efficiency and electricity cost that would otherwise be associated with an increase in weight.

[0015] In the laminated glass of the present embodiment, the SiO content of the first glass sheet is expressed as mass % on an oxide basis. ２ and the SiO content of the second glass plate ２ the difference between the content of Al in the first glass sheet and that of Al in the second glass sheet is 1.0 mass % or less, ２ O ３ and the Al content of the second glass plate ２ O ３ the difference between the content of B in the first glass plate and the content of B in the second glass plate is 1.0 mass % or less, ２ O ３ and the content of B contained in the second glass plate ２ O ３ the difference between the contents of MgO contained in the first glass plate and the second glass plate is 1.0% by mass or less; the difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 1.0% by mass or less; the difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 1.0% by mass or less; the difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 1.0% by mass or less; ２ The content of O and the Li content of the second glass plate ２The difference between the content of Na and the content of O contained in the first glass plate is 1.0 mass % or less, ２ The O content and the Na content of the second glass plate ２ The difference between the content of K and the content of O is 1.0 mass % or less, and ２ The content of O and the content of K in the second glass plate ２ The difference between the content of Fe and O in the first glass sheet is 1.0 mass % or less, and ２ O ３ and the Fe content of the second glass plate ２ O ３ Since the difference between the contents of the first and second glass sheets is 1.0 mass % or less, there is little difference in composition between the glass sheets, resulting in excellent recyclability. Furthermore, since the thermal properties of the first and second glass sheets are similar, the glass is excellent in bendability, and since the refractive indices are also similar, the visibility of the laminated glass is also excellent.

[0016] The difference between the content of each of the glass components contained in the first glass plate and the content of each of the glass components contained in the second glass plate is preferably 0.6% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, still more preferably 0.2% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass.

[0017] Furthermore, in the laminated glass of this embodiment, the thickness t1 of the first glass plate is 3.0 mm or more and the thickness t2 of the second glass plate is 1.1 mm or more, thereby providing a laminated glass with high strength. In particular, when the laminated glass of this embodiment is used as an automobile window glass, if the glass plate facing the exterior of the vehicle is the first glass plate and the glass plate facing the interior of the vehicle is the second glass plate, having the thickness t1 of the first glass plate facing the exterior of the vehicle of 3.0 mm or more has the advantage of increasing durability against impact objects such as flying stones, and having the thickness t2 of the second glass plate facing the interior of the vehicle of 1.1 mm or more has the advantage of increasing durability against scratches caused by objects hitting the glass on the interior of the vehicle.

[0018] The thickness t1 of the first glass plate is preferably 3.1 mm or more, more preferably 3.2 mm or more, and even more preferably 3.3 mm or more. From the viewpoints of suppressing weight gain of the laminated glass and facilitating bending, the thickness t1 of the first glass plate is preferably 6.0 mm or less, more preferably 5.0 mm or less, even more preferably 4.5 mm or less, even more preferably 4.0 mm or less, particularly preferably 3.8 mm or less, and most preferably 3.6 mm or less. The thickness t2 of the second glass plate is preferably 1.2 mm or more, more preferably 1.3 mm or more, even more preferably 1.4 mm or more, and particularly preferably 1.5 mm or more. From the viewpoint of suppressing weight gain of the laminated glass, the thickness t2 of the second glass plate is preferably 3.0 mm or less, more preferably 2.8 mm or less, even more preferably 2.6 mm or less, even more preferably 2.4 mm or less, particularly preferably 2.2 mm or less, and most preferably 2.0 mm or less.

[0019] The ratio (t1 / t2) of the thickness t1 of the first glass plate to the thickness t2 of the second glass plate is preferably 1.0 to 5.5, more preferably 1.2 to 5.5, from the viewpoint of improving the durability and bending formability of the laminated glass. t1 / t2 is preferably 1.0 or more, more preferably 1.1 or more, even more preferably 1.2 or more, even more preferably 1.5 or more, particularly preferably 1.7 or more, and most preferably 2.0 or more. When the laminated glass of this embodiment is used as an automotive window glass, if the glass plate facing the exterior of the vehicle is the first glass plate and the glass plate facing the interior of the vehicle is the second glass plate, the thickness t1 of the first glass plate facing the exterior of the vehicle is not smaller than the thickness t2 of the second glass plate facing the interior of the vehicle, thereby improving durability against collisions such as flying stones. Furthermore, when the laminated glass of this embodiment is used as an automobile window glass, if the glass plate facing the exterior of the vehicle is the first glass plate and the glass plate facing the interior of the vehicle is the second glass plate, the thickness t1 of the first glass plate facing the exterior of the vehicle is greater than the thickness t2 of the second glass plate facing the interior of the vehicle, thereby improving durability against collisions such as flying stones. Furthermore, t1 / t2 is preferably 5.5 or less, more preferably 5.0 or less, even more preferably 4.5 or less, particularly preferably 4.0 or less, and most preferably 3.5 or less. When t1 / t2 is 5.5 or less, it becomes easy to control the shape of the laminated glass after bending.

[0020] The first glass plate, the second glass plate, and the interlayer film that constitute the laminated glass of this embodiment will be described in detail below.

[0021] <First Glass Sheet and Second Glass Sheet> (Glass Composition) The glass composition of at least one of the first glass sheet and the second glass sheet in this embodiment (hereinafter also simply referred to as the glass sheet of this embodiment) is, in mass % on an oxide basis, 50%≦SiO ２ ≦85% 1.0%≦Al ２ O ３ ≦15% 5.0%≦B ２ O ３≦20% 0.0%≦MgO≦20% 0.0%≦CaO≦20% 0.0%≦SrO≦20% 0.0%≦BaO≦20% 0.0%≦Li ２ O≦20% 0.0%≦Na ２ O≦20% 0.0%≦K ２ O≦20% 0.010%≦Fe ２ O ３ ≦5.0% 1.0%≦R′ ２ O≦20% 0.0%≦RO≦20% (wherein RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is Li ２ O, Na ２ O and K ２ The total content of O is preferably 1.0 to 1.0.

[0022] The glass composition of at least one of the first glass sheet and the second glass sheet is, in mass % on an oxide basis, 65%≦SiO ２ ≦80% 2.0%≦Al ２ O ３ ≦6.0% 10%≦B ２ O ３ ≦17% 0.0%≦MgO≦5.0% 0.0%≦CaO≦5.0% 0.0%≦SrO≦5.0% 0.0%≦BaO≦5.0% 0.0%≦Li ２ O≦5.0% 4.0%≦Na ２ O≦12% 0.0%≦K ２ O≦5.0% 0.020%≦Fe ２ O ３ ≦1.0% 5.0%≦R′ ２ O≦15% 0.0%≦RO≦5.0% (wherein RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is Li ２ O, Na ２ O and K ２ It is more preferable that the total content of O is 1.0 or less.

[0023] A preferred composition range of each component in the glass plate of this embodiment will be described below. Note that the composition range of each component is expressed in mass % based on the oxide unless otherwise specified.

[0024] SiO ２ is a component that contributes to improving the Young's modulus, thereby making it easier to ensure the strength required for vehicle applications, etc. In this embodiment, SiO ２ The content of SiO is preferably 50% or more and 85% or less. ２ By making the content of SiO 50% or more, it is easy to reduce the specific gravity of the glass, and furthermore, it is possible to ensure weather resistance and chemical durability. In addition, it is possible to prevent the average linear expansion coefficient from increasing, and to suppress thermal cracking of the glass. ２ The content of SiO is more preferably 65% ​​or more, further preferably 67% or more, particularly preferably 69% or more, and most preferably 70% or more. ２ By ensuring that the content of SiO is 85% or less, an increase in viscosity during glass melting is suppressed, making glass production easier and improving the formability of window glass for vehicles, particularly windshields, etc. ２ The content is more preferably 80% or less, even more preferably 78% or less, even more preferably 76% or less, particularly preferably 75% or less, and most preferably 74% or less.

[0025] In this embodiment, Al ２ O ３ The content of Al is preferably 1.0% or more and 15% or less. ２ O ３ is 1.0% or more, the alkali metal is coordinated with tetrahedral Al ２ O ３ The formation of Al reduces non-bridging oxygen in the glass, improving weather resistance, discoloration resistance, and chemical durability. In addition, the average linear expansion coefficient does not become too large, suppressing thermal cracking of the glass, and enabling chemical strengthening treatment using ion exchange. ２ O ３ The content of Al is more preferably 2.0% or more, even more preferably 2.1% or more, even more preferably 2.2% or more, particularly preferably 2.3% or more, and most preferably 2.4% or more. ２ O ３By making the Al content 15% or less, an increase in viscosity during glass melting is suppressed, facilitating glass production, and also improving formability for window glass for vehicles, particularly windshields and the like. ２ O ３ The content is more preferably 6.0% or less, even more preferably 5.8% or less, even more preferably 5.5% or less, particularly preferably 5.2% or less, and most preferably 5.0% or less.

[0026] B ２ O ３ As described above, B controls the optical properties of the glass, reduces the specific gravity of the glass, and also contributes to improving the strength and meltability of the glass. ２ O ３ The content of B is preferably 5.0% or more and 20% or less. ２ O ３ By setting the content of B to 5.0% or more, the optical properties of the glass can be controlled, and the specific gravity of the glass can be reduced, and the strength and meltability of the glass can be improved. ２ O ３ The content of B is preferably 10% or more, more preferably 11% or more, even more preferably 12% or more, and particularly preferably 13% or more. ２ O ３ By keeping the content of B to 20% or less, alkali elements are less likely to volatilize during the melting and forming of the glass, and deterioration of the glass quality can be suppressed. In addition, acid resistance and alkali resistance can be improved. ２ O ３ The content is more preferably 17% or less, further preferably 16% or less, particularly preferably 15% or less, and most preferably 14% or less.

[0027] MgO is a component that promotes the melting of glass raw materials and improves weather resistance, discoloration resistance, and Young's modulus. In this embodiment, the MgO content is preferably 0.0% or more and 20% or less. When MgO is contained, its content is more preferably 0.10% or more, even more preferably 0.20% or more, even more preferably 0.50% or more, particularly preferably 0.70% or more, and most preferably 1.0% or more, from the viewpoint of improving meltability and Young's modulus. Furthermore, if the MgO content is 20% or less, the glass is less likely to devitrify, and an increase in viscosity during glass melting is suppressed, facilitating glass production and improving the formability of vehicle window glass, particularly windshields, etc. The MgO content is more preferably 5.0% or less, even more preferably 4.0% or less, particularly preferably 3.0% or less, and most preferably 2.0% or less.

[0028] CaO is a component that improves the meltability of glass raw materials. In this embodiment, the CaO content is preferably 0.0% or more and 20% or less. When CaO is contained, its content is more preferably 0.10% or more, even more preferably 0.20% or more, even more preferably 0.50% or more, particularly preferably 0.70% or more, and most preferably 1.0% or more. This improves the meltability of glass raw materials and the formability of vehicle window glass, particularly windshields, etc. Furthermore, by keeping the CaO content 20% or less, an increase in the density of the glass is avoided, low brittleness is suppressed, and strength is maintained. The CaO content is more preferably 5.0% or less, even more preferably 4.0% or less, particularly preferably 3.0% or less, and most preferably 2.0% or less.

[0029] SrO is a component that improves the meltability of glass raw materials. On the other hand, it is preferable not to actively include SrO because it may increase the specific gravity of the glass or reduce its brittleness, thereby reducing the strength of the glass. In this embodiment, the SrO content is preferably 0.0% or more and 20% or less. When SrO is included in this embodiment, the content is more preferably 0.10% or more, even more preferably 0.20% or more, still more preferably 0.30% or more, particularly preferably 0.40% or more, and most preferably 0.50% or more. This improves the meltability of glass raw materials and the formability of vehicle window glass, particularly windshields, etc. In addition, the SrO content is preferably 20% or less. By setting the SrO content to 20% or less, an increase in the specific gravity of the glass can be suppressed. In addition, an increase in the density of the glass is avoided, low brittleness is suppressed, and strength is maintained. The SrO content is more preferably 5.0% or less, further preferably 3.0% or less, particularly preferably 2.0% or less, and most preferably 1.0% or less.

[0030] BaO is a component that improves the meltability of glass raw materials. However, it is preferable not to actively include BaO because it may increase the specific gravity of the glass or reduce its brittleness, thereby reducing the strength of the glass. In this embodiment, the BaO content is preferably 0.0% or more and 20% or less. When BaO is included, its content is more preferably 0.10% or more, even more preferably 0.20% or more, even more preferably 0.30% or more, particularly preferably 0.40% or more, and most preferably 0.50% or more. This improves the meltability of glass raw materials and the formability of vehicle window glass, particularly windshields, etc. Furthermore, the BaO content is preferably 20% or less. By keeping the BaO content 20% or less, an increase in the specific gravity of the glass can be suppressed. Furthermore, an increase in the density of the glass is avoided, low brittleness is suppressed, and strength is maintained. The BaO content is more preferably 5.0% or less, further preferably 3.0% or less, particularly preferably 2.0% or less, and most preferably 1.0% or less.

[0031] Li ２O is a component that significantly improves the melting property of glass with the addition of a small amount, and also makes it easier to increase the Young's modulus and contributes to the linear expansion coefficient of the glass. ２ The content of O is preferably 0.0% or more and 20% or less. ２ By including O, the viscosity of the glass is reduced, and therefore the formability of window glass for vehicles, particularly windshields, etc. is improved. ２ When O is contained, the content is preferably 0.20% or more, more preferably 0.50% or more, even more preferably 0.70% or more, particularly preferably 1.0% or more, and most preferably 1.2% or more. ２ By making the O content 20% or less, the occurrence of devitrification or phase separation during glass production is suppressed, facilitating production, and the linear expansion coefficient can be reduced, thereby suppressing thermal cracking of the glass. In addition, since lithium raw materials are expensive, there is also the effect of reducing raw material costs. ２ The O content is more preferably 5.0% or less, further preferably 4.0% or less, particularly preferably 3.0% or less, and most preferably 2.0% or less.

[0032] Na ２ O is a component that improves the meltability of glass, and also makes it easier to increase the Young's modulus and contributes to the linear expansion coefficient of glass. The strength of glass can be increased by performing a chemical strengthening treatment by ion exchange of Na ions and K ions. In this embodiment, Na ２ The content of O is preferably 0.0% or more and 20% or less. ２ By including O, the viscosity of the glass is reduced, and therefore the formability of the window glass for a vehicle, particularly the windshield, is improved. ２ When O is contained, the content is more preferably 4.0% or more, even more preferably 4.5% or more, even more preferably 5.0% or more, still more preferably 5.5% or more, particularly preferably 6.0% or more, and most preferably 6.5% or more. ２By keeping the O content at 20% or less, the linear expansion coefficient can be reduced and thermal cracking of the glass can be suppressed. In addition, the glass has improved tarnish resistance, making it suitable for use as glass exposed to the atmosphere for long periods of time, such as vehicle window glass. ２ The O content is more preferably 12% or less, further preferably 11% or less, particularly preferably 10% or less, and most preferably 9.5% or less.

[0033] K ２ O is a component that improves the meltability of glass, and also increases the Young's modulus and contributes to the linear expansion coefficient of glass. ２ The O content is preferably 0.0% or more and 20% or less. ２ By including O, the viscosity of the glass is reduced, and therefore the formability of the window glass for a vehicle, particularly the windshield, is improved. ２ O is Li ２ O and Na ２ Li has the effect of increasing the linear expansion coefficient and specific gravity compared to O. ２ O and Na ２ It is desirable to add a small amount compared to O. ２ When O is contained, the content is more preferably 0.10% or more, further preferably 0.20% or more, particularly preferably 0.30% or more, extremely preferably 0.40% or more, and most preferably 0.50% or more. ２ By keeping the O content at 20% or less, increases in the linear expansion coefficient and specific gravity can be suppressed. ２ The O content is more preferably 5.0% or less, further preferably 4.0% or less, particularly preferably 3.0% or less, and most preferably 2.5% or less.

[0034] In this embodiment, SiO ２ +Al ２ O ３ +B ２ O ３ , i.e., SiO ２ Content and Al ２ O ３ Content and B ２ O ３ The total content is preferably 85% or more. ２ +Al２ O ３ +B ２ O ３ When the SiO content is 85% or more, the specific gravity of the glass decreases, and the weather resistance and tarnish resistance of the glass are improved. In addition, the linear expansion coefficient of the glass can be prevented from becoming too high, making the glass suitable for use as a window glass for vehicles. ２ +Al ２ O ３ +B ２ O ３ is more preferably 87% or more, and particularly preferably 88% or more. ２ +Al ２ O ３ +B ２ O ３ From the viewpoint of improving the meltability of glass raw materials and the formability of vehicle window glass, particularly windshields and the like, the porosity is preferably 97% or less, more preferably 95% or less, even more preferably 94% or less, still more preferably 93% or less, particularly preferably 92% or less, and most preferably 91% or less.

[0035] Fe ２ O ３ may be contained to impart heat-shielding properties. ２ O ３ The content of Fe is preferably 0.010% or more and 5.0% or less. ２ O ３ The content of FeO, which is an oxide of divalent iron, and Fe, which is an oxide of trivalent iron ２ O ３ means the total amount of iron, including Fe ２ O ３ The FeO content converted to Fe ２ O ３ The total content of Fe ２ O ３ When the content of Fe is 0.010% or more, the material can be suitably used in applications where heat insulation properties are required. ２ O ３ The content of is preferably 0.020% or more, more preferably 0.050% or more, even more preferably 0.080% or more, still more preferably 0.10% or more, particularly preferably 0.15% or more, and most preferably 0.20% or more.

[0036] On the other hand, Fe ２ O ３ When the content of Fe is 5.0% or less, heat transfer by radiation is not hindered during production, and the raw materials are easily melted. Furthermore, the light transmittance in the visible range is not reduced, making the glass suitable for applications such as automobile window glass. ２ O ３ The content of is preferably 1.0% or less, more preferably 0.80% or less, further preferably 0.70% or less, particularly preferably 0.60% or less, and most preferably 0.55% or less.

[0037] In addition, the above Fe ２ O ３ The iron ions contained in the ２＋ ] / ([Fe ２＋ ]+[Fe ３＋ ])≦0.80. This improves the transmittance of the glass plate for light in the range of 900 to 1300 nm. ２＋ ] / ([Fe ２＋ ]+[Fe ３＋ If the redox is too low, the heat insulating property of the glass sheet will be deteriorated. On the other hand, if the redox is too high, the glass sheet may not be able to transmit the light of infrared irradiation devices such as lasers and radars, and the ultraviolet absorption property may be reduced. ２＋ ], and [Fe ３＋ ] respectively represent Fe contained in the borosilicate glass of this embodiment. ２＋ , and Fe ３＋ Also, "Fe" means the content of ２＋ ] / ([Fe ２＋ ]+[Fe ３＋ ]) refers to the Fe in the borosilicate glass of this embodiment. ２＋ and Fe ３＋ Fe relative to the total content of ２＋ It means the content ratio of [Fe ２＋ ] / ([Fe ２＋ ]+[Fe ３＋From the viewpoint of improving heat-shielding properties, the value of [Ratio of Redox Value to Calcium Carbonate] is preferably 0.17 or more, more preferably 0.20 or more, even more preferably 0.23 or more, and particularly preferably 0.25 or more. From the viewpoint of reducing the load on equipment under high reduction conditions and suppressing amber coloring caused by high redox when sulfur is used as a fining agent, the value of [Ratio of Redox Value to Calcium Carbonate] is preferably 0.75 or less, more preferably 0.70 or less, even more preferably 0.65 or less, even more preferably 0.60 or less, particularly preferably 0.55 or less, and most preferably 0.50 or less.

[0038] [Fe ２＋ ] / ([Fe ２＋ ]+[Fe ３＋ The Fe content of the sample solution is determined by the following method: After the crushed glass is decomposed at room temperature with a mixture of hydrofluoric acid and hydrochloric acid, a certain amount of the decomposed solution is dispensed into a plastic container, and a hydroxylammonium chloride solution is added to the decomposed solution. ３＋ Fe ２＋ Then, 2,2'-dipyridyl solution and ammonium acetate buffer are added to reduce Fe ２＋ The coloring solution is adjusted to a certain volume with ion-exchanged water, and the absorbance at a wavelength of 522 nm is measured using an absorptiometer. The concentration is then calculated from a calibration curve prepared using the standard solution. ２＋ Calculate the amount of Fe in the sample solution. ３＋ Fe ２＋ Since it is reduced to this Fe ２＋ The amount of "[Fe ２＋ ]+[Fe ３＋ Next, the crushed glass was decomposed at room temperature using a mixture of hydrofluoric acid and hydrochloric acid, and a certain amount of the decomposition solution was dispensed into a plastic container. A 2,2'-dipyridyl solution and an ammonium acetate buffer solution were quickly added to the decomposition solution to remove Fe. ２＋ The coloring solution is adjusted to a certain volume with ion-exchanged water, and the absorbance at a wavelength of 522 nm is measured using an absorptiometer. The concentration is then calculated from a calibration curve prepared using the standard solution, and the Fe concentration is calculated. ２＋ The amount of Fe is calculated. ２＋ The amount of [Fe ２＋ ]. And, the above-obtained [Fe ２＋ ], and [Fe２＋ ]+[Fe ３＋ ] to [Fe ２＋ ] / ([Fe ２＋ ]+[Fe ３＋ ]) is calculated.

[0039] In this embodiment, R' ２ O content, i.e., Li ２ O, Na ２ O and K ２ The total content of O is preferably 1.0% or more. ２ O is Li ２ O, Na ２ O and K ２ O. ２ O content, i.e., Li ２ O, Na ２ O and K ２ When the total O content is 1.0% or more, the Young's modulus is increased, the viscosity of the glass is reduced, and formability is improved, making the glass suitable for vehicle window glass, particularly windshields. Furthermore, the linear expansion coefficient can be increased within a range that does not cause thermal cracking of the glass, and the strength of the glass can be improved by performing an air-cooling tempering treatment. ２ O content, i.e., Li ２ O, Na ２ O and K ２ The total content of O is more preferably 5.0% or more, even more preferably 6.0% or more, even more preferably 6.5% or more, still more preferably 7.0% or more, particularly preferably 7.5% or more, and most preferably 8.0% or more. ２ O content, i.e., Li ２ O, Na ２ O and K ２ From the viewpoint of improving the scorching resistance, the total content of O is preferably 20% or less, more preferably 15% or less, even more preferably 14% or less, particularly preferably 13% or less, and most preferably 12% or less. ２ O, Na ２ O and K ２ In O, Li ２O has the smallest molecular weight and contributes to reducing the weight of the glass, and also contributes greatly to reducing the viscosity of the glass and improving the Young's modulus. ２ O, Na ２ O and K ２ Among O, Li ２ It is preferable that the glass contains O. Furthermore, from the viewpoint of improving the scorch resistance due to the alkali mixing effect and suppressing phase separation and devitrification, it is preferable that the glass contains two or more types of alkali metal components.

[0040] In this embodiment, the RO content, i.e., the total content of MgO, CaO, SrO, and BaO, is preferably 0.0% or more and 20% or less. The RO, which is a glass component, is at least one selected from MgO, CaO, SrO, and BaO. When the RO content, i.e., the total content of MgO, CaO, SrO, and BaO, is 20% or less, the boron coordination number can be controlled while suppressing a decrease in the brittleness of the glass and maintaining the strength of the glass. The RO content, i.e., the total content of MgO, CaO, SrO, and BaO, is more preferably 5.0% or less, even more preferably 4.0% or less, even more preferably 3.0% or less, even more preferably 2.0% or less, particularly preferably 1.5% or less, and most preferably 1.0% or less. Furthermore, from the viewpoint of improving the formability of a vehicle window glass, in particular a windshield, the content of RO, i.e., the total content of MgO, CaO, SrO, and BaO, is more preferably 0.10% or more, further preferably 0.20% or more, still more preferably 0.30% or more, particularly preferably 0.40% or more, and most preferably 0.50% or more.

[0041] The glass plate of this embodiment is made of the above-mentioned SiO ２ , Al ２ O ３ , B ２ O ３ , MgO, CaO, SrO, BaO, Li ２ O, Na ２ O.K. ２ O, FeO and Fe ２ O ３ The composition may contain components other than those mentioned above (hereinafter also referred to as "other components"), and when such components are contained, the total content thereof is preferably 5.0% or less.

[0042] Other components include, for example, ZrO ２ , Y ２ O ３ , TiO ２ , CeO ２ , Nd ２ O ５ , GaO ２ , GeO ２ , MnO ２ , NiO, Cr ２ O ３ , V ２ O ５ , Er ２ O ３ , Au ２ O ３ , Ag ２ O, CuO, CdO, MoO ３ , S.O. ３ , Cl, F, SnO ２ , Sb ２ O ３ These may be metal ions or oxides. Other components may be contained in an amount of up to 5.0% for various purposes (e.g., fining and coloring). If the content of other components exceeds 5.0%, SiO ２ +Al ２ O ３ +B ２ O ３ If the glass is less than 85%, there is a risk of an increase in the specific gravity of the glass and a decrease in weather resistance and discoloration resistance. ２ If the O content is less than 5.0%, the Young's modulus may decrease and the viscosity of the glass may increase. The content of other components is preferably 4.0% or less, more preferably 2.0% or less, even more preferably 1.0% or less, particularly preferably 0.50% or less, and most preferably 0.10% or less. Er ２ O ３ As with Se, As has the effect of adding reddishness to glass, but is a rare element and is expensive, and is not suitable for use in mass production processes such as the float method, roll-out method, and down-draw method described below from the viewpoint of reserves. Therefore, the As content is preferably less than 0.0015%, and it is more preferable that As is not substantially contained. ２ O ３The content of each of Pb and PbO is preferably less than 0.0020%, and more preferably substantially zero.

[0043] In the glass plate of the present embodiment, if NiO is contained, NiS may be generated, which may cause glass breakage, so the NiO content is preferably 0.0080% or less, more preferably 0.0040% or less, and even more preferably 0.0020% or less, and further preferably the glass plate is substantially free of NiO.

[0044] The glass plate of this embodiment is TiO ２ It may contain TiO ２ Since TiO has absorption in the ultraviolet region, it reduces the ultraviolet transmittance Tuv and improves the UV blocking performance. ２ When TiO is contained, its content is preferably 0.010% or more, more preferably 0.040% or more, further preferably 0.075% or more, and particularly preferably 0.15% or more. ２ Since the glass plate of this embodiment contains TiO , the visible light transmittance Tv may decrease and the color of the glass may change from gray to brown. ２ When it is contained, the content is preferably 0.80% or less, more preferably 0.50% or less, further preferably 0.40% or less, and particularly preferably 0.30% or less.

[0045] The glass plate of this embodiment is CeO ２ It may contain CeO ２ Since the glass plate of this embodiment has absorption in the ultraviolet region, it reduces the ultraviolet transmittance Tuv and improves the UV blocking performance. ２ When CeO is contained, its content is preferably 0.010% or more, more preferably 0.020% or more, further preferably 0.040% or more, and particularly preferably 0.070% or more. ２ When the glass plate of the present embodiment contains CeO, solarization occurs due to the absorption of ultraviolet light, which reduces the transmittance in the visible range and may cause the glass to lose its gray color. ２When it is contained, the content is preferably 0.25% or less, more preferably 0.18% or less, further preferably 0.14% or less, particularly preferably 0.10% or less.

[0046] The glass plate of this embodiment is made of Cr ２ O ３ Cr ２ O ３ acts as an oxidizing agent to ２＋ The amount of Cr can be controlled. ２ O ３ When Cr is contained, its content is preferably 0.0020% or more, and more preferably 0.0040% or more. ２ O ３ Since the glass plate of this embodiment is colored with respect to light in the visible range, there is a risk of a decrease in visible light transmittance. ２ O ３ When it is contained, the content is preferably 0.020% or less, more preferably 0.016% or less, further preferably 0.012% or less, and particularly preferably 0.0080% or less.

[0047] The glass plate of this embodiment is SnO ２ It may contain SnO ２ acts as a reducing agent and can control the amount of FeO. ２ When SnO is contained, its content is preferably 0.010% or more, more preferably 0.040% or more, further preferably 0.060% or more, and particularly preferably 0.080% or more. ２ In order to suppress defects caused by SnO in the glass plate of this embodiment, ２ The content of is preferably 0.40% or less, more preferably 0.30% or less, further preferably 0.20% or less, particularly preferably 0.15% or less.

[0048] The glass plate of this embodiment is SO ３ SO ３ acts as a fining agent to improve the bubble quality of the glass. ３When SO is contained, its content is preferably 0.0010% or more, more preferably 0.0040% or more, further preferably 0.0070% or more, and particularly preferably 0.015% or more. ３ If the redox is high, amber coloring may occur and the glass may turn brown. ３ When it is contained, the content is preferably 0.070% or less, more preferably 0.060% or less, further preferably 0.050% or less, and particularly preferably 0.040% or less.

[0049] The glass sheet of this embodiment may contain Cl. Cl acts as a fining agent and improves the bubble quality of the glass. When the glass sheet of this embodiment contains Cl, the Cl content is preferably 0.080% or more, more preferably 0.15% or more, even more preferably 0.20% or more, particularly preferably 0.30% or more, and most preferably 0.40% or more. If the Cl content is high, Cl volatilized from the glass melt may cause the glass to bubble. ２ The gas may corrode surrounding members. When the glass plate of the present embodiment contains Cl, the Cl content is preferably 1.5% or less, more preferably 1.2% or less, even more preferably 1.0% or less, and particularly preferably 0.80% or less.

[0050] <Air-cooled tempering> From the viewpoint of improving strength, at least one of the first glass sheet and the second glass sheet is preferably air-cooled tempered glass. Here, air-cooled tempering is a process for forming a compressive stress layer on the glass surface by thermal tempering. Specifically, a uniformly heated glass sheet is rapidly cooled from a temperature near its softening point, and compressive stress is formed on the glass surface due to the temperature difference between the glass surface and the interior of the glass. The compressive stress is generated uniformly over the entire glass surface, and a compressive stress layer of uniform depth is formed over the entire glass surface. Thermal tempering is more suitable for tempering thick glass sheets than chemical tempering.

[0051] <Chemical Strengthening> From the viewpoint of improving strength, at least one of the first glass plate and the second glass plate is preferably chemically strengthened glass. Here, chemical strengthening is a process in which alkali metal ions (typically Li ions or Na ions) with a small ionic radius on the glass surface are exchanged with alkali metal ions (typically Na ions or K ions) with a larger ionic radius by ion exchange at a temperature below the glass transition point, thereby forming a compressive stress layer on the glass surface. The chemical strengthening treatment method can be performed by a known method, such as an ion exchange method. In the ion exchange method, the glass plate is immersed in a treatment liquid (e.g., potassium nitrate molten salt) and ions with a small ionic radius (e.g., Na ions) contained in the glass are exchanged for ions with a large ionic radius (e.g., K ions), thereby generating compressive stress on the glass surface. The magnitude of the compressive stress on the glass plate surface (hereinafter also referred to as surface compressive stress CS) and the depth DOL of the compressive stress layer formed on the glass plate surface can be adjusted by the glass composition, chemical strengthening treatment time, and chemical strengthening treatment temperature, respectively.

[0052] In particular, when the laminated glass of this embodiment is used as an automobile window glass, if the glass plate facing the outside of the vehicle is the first glass plate and the glass plate facing the inside of the vehicle is the second glass plate, it is preferable that the first glass plate is air-cooled tempered glass and the second glass plate is chemically tempered glass. This is because air-cooled tempered glass with a deep DOL is more resistant to collision objects such as flying stones and is suitable for the first glass plate, and when an object hits the inside of the vehicle, the chemically tempered glass plate can sufficiently increase the strength and is therefore suitable for the second glass plate.

[0053] <Other Properties> (Rigidity Modulus) The rigidity modulus of at least one of the first glass plate and the second glass plate of this embodiment is preferably 23 GPa or more. If the rigidity modulus is 23 GPa or more, the glass is less likely to deform when subjected to an external force. The rigidity modulus is more preferably 25 GPa or more, and even more preferably 27 GPa or more. Furthermore, since deformation occurs when the glass is subjected to an external force, consuming energy and thereby suppressing cracking, the rigidity modulus is preferably 37 GPa or less, more preferably 35 GPa or less, even more preferably 34 GPa or less, and particularly preferably 33 GPa or less. The rigidity modulus may be, for example, 23 GPa or more and 37 GPa or less. The rigidity modulus can be measured by an ultrasonic pulse method based on JIS R1602:1995 "Test Method for Elastic Modulus of Fine Ceramics."

[0054] (Poisson's ratio) The Poisson's ratio of at least one of the first glass plate and the second glass plate in this embodiment is preferably 0.25 or less. A Poisson's ratio of 0.25 or less can reduce stress generated when an external force is applied to the glass. The Poisson's ratio is more preferably 0.24 or less, even more preferably 0.23 or less, particularly preferably 0.22 or less, and most preferably 0.21 or less. The lower limit of the Poisson's ratio is not particularly limited, but may be 0.10 or more. The Poisson's ratio may be, for example, 0.10 or more and 0.25 or less. The Poisson's ratio can be measured by an ultrasonic pulse method based on JIS R1602:1995 "Testing Method for Elastic Modulus of Fine Ceramics."

[0055] (Young's Modulus) The Young's modulus of at least one of the first glass plate and the second glass plate according to this embodiment is preferably 60 GPa or more, more preferably 63 GPa or more, even more preferably 65 GPa or more, particularly preferably 67 GPa or more, and most preferably 70 GPa or more. With the Young's modulus in the above range, the glass has high rigidity and is more suitable for use as vehicle window glass, etc. On the other hand, if the Young's modulus is too high, the glass becomes difficult to deform, and there is a risk that the glass will break due to an inability to absorb the energy of a stone impact. Therefore, the Young's modulus is preferably 85 GPa or less, more preferably 83 GPa or less, even more preferably 80 GPa or less, particularly preferably 79 GPa or less, and most preferably 78 GPa or less. The Young's modulus may be, for example, 60 GPa or more and 85 GPa or less. The Young's modulus can be measured by an ultrasonic pulse method based on JIS R1602:1995 "Test Method for Elastic Modulus of Fine Ceramics."

[0056] (T １１ At least one of the first glass plate and the second glass plate according to this embodiment has a glass viscosity of 10 １１ [dPa s] Temperature T １１ It is preferable that T １１ By keeping the temperature at 670°C or less, bending can be performed at a low temperature. １１ As a method for reducing the temperature to 670°C or less, for example, ２ O ３ , R ２ Increase the content of O and RO, and Al ２ O ３ A method for reducing the content of R ２ Among O, Li ２ At least one of the first glass plate and the second glass plate according to this embodiment may contain T １１ The firing temperature is more preferably 650°C or less, even more preferably 640°C or less, even more preferably 635°C or less, particularly preferably 630°C or less, and most preferably 625°C or less. １１is preferably 560°C or higher, more preferably 570°C or higher, even more preferably 575°C or higher, and particularly preferably 580°C or higher. １１ may be, for example, 560°C or higher and 670°C or lower. １１ can be measured by the beam bending method.

[0057] (T １２ At least one of the first glass plate and the second glass plate according to this embodiment has a glass viscosity of 10 １２ [dPa s] Temperature T １２ It is preferable that T １２ By keeping the temperature at 630°C or less, bending forming can be performed at a low temperature. １２ As a method for reducing the temperature to 630°C or less, for example, ２ O ３ , R ２ Increase the content of O and RO, and Al ２ O ３ A method for reducing the content of R ２ Among O, Li ２ At least one of the first glass plate and the second glass plate according to this embodiment may contain T １２ is more preferably 625°C or less, even more preferably 620°C or less, even more preferably 615°C or less, particularly preferably 610°C or less, and most preferably 605°C or less. １２ is preferably 540°C or higher, more preferably 545°C or higher, even more preferably 550°C or higher, particularly preferably 555°C or higher, and most preferably 560°C or higher. １２ may be, for example, 540°C or higher and 630°C or lower. １２ can be measured by the beam bending method.

[0058] (Average Linear Expansion Coefficient) The average linear expansion coefficient of at least one of the first glass plate and the second glass plate according to this embodiment at 50°C to 350°C is 30 × 10 －７At least one of the first glass plate and the second glass plate according to this embodiment preferably has an average linear expansion coefficient of 30×10 －７ / °C or more, the treatment by air-cooling tempering becomes easy, and the difference in the linear expansion coefficient between the glass and the black ceramic becomes small, thereby suppressing cracking of the black ceramic. ２ O ３ , R ２ Increase the content of O and RO, and Al ２ O ３ The average linear expansion coefficient of at least one of the first glass plate and the second glass plate according to this embodiment at 50°C to 350°C is 35 × 10 －７ / °C or more is more preferable, and 40 x 10 －７ / °C or more is more preferable, and 45 x 10 －７ / °C or more is particularly preferred, and 50 x 10 －７ / °C or more is most preferable. On the other hand, if the average linear expansion coefficient of at least one of the first glass plate and the second glass plate according to this embodiment is too large, thermal stress due to the temperature distribution of the glass is likely to occur in the glass forming process, the annealing process, or the windshield forming process, and thermal cracking of the glass may occur. Furthermore, if the average linear expansion coefficient of at least one of the first glass plate and the second glass plate according to this embodiment is too large, cracking due to heat shock may occur when used as a vehicle window glass or the like. The average linear expansion coefficient of at least one of the first glass plate and the second glass plate according to this embodiment at 50°C to 350°C is 80 x 10 －７ / °C or less, and －７ / °C or less, and 70 x 10 －７ / °C or less is more preferable, and 68 x 10 －７ / °C or less is more preferable, and 65 × 10 －７ / °C or less is particularly preferred, and 63 x 10 －７ / °C or less. The average linear expansion coefficient is, for example, 30 x 10 －７ / ℃ or more 80 x 10 －７ / ° C. or less. The average coefficient of linear expansion can be measured using a differential thermal dilatometer (TMA) according to JIS R3102:1995.

[0059] (Density) The density of at least one of the first glass plate and the second glass plate according to this embodiment is 2.50 g / cm ３ Soda lime glass, which is widely used as vehicle glass, has a density of about 2.51 g / cm ３ However, at least one of the first glass plate and the second glass plate according to this embodiment is made of borosilicate glass, which has a lower density than soda-lime glass, and is therefore lightweight, and from the viewpoints of fuel economy and electric power consumption, can be more suitably used as window glass for vehicles. The density of at least one of the first glass plate and the second glass plate according to this embodiment is 2.48 g / cm ３ More preferably, 2.45 g / cm ３ More preferably, 2.42 g / cm ３ The following is particularly preferred: 2.40 g / cm ３ From the viewpoint of enhancing sound insulation in a vehicle interior, it is most preferable that the density of at least one of the first glass plate and the second glass plate according to this embodiment is 2.20 g / cm or less. ３ More than 2.22 g / cm ３ More preferably, 2.25 g / cm ３ More preferably, 2.27 g / cm ３ More than 2.30 g / cm is particularly preferred. ３ The density is most preferably 2.20 g / cm or more. ３ 2.48g / cm or more ３ The density can be measured by Archimedes' method.

[0060] In addition, in at least one of the first glass plate and the second glass plate according to this embodiment, T ２．５ In at least one of the first glass plate and the second glass plate according to this embodiment, T ４ is preferably 1250°C or less, and T ４ -TＬ is preferably −50° C. or higher. ２．５ is the glass viscosity is 10 ２．５ represents the temperature at which the viscosity becomes dPa s, and T ４ is the glass viscosity is 10 ４ represents the temperature at which the viscosity becomes dPa s, and T Ｌ represents the liquidus temperature of the glass. At least one of the first glass plate and the second glass plate according to this embodiment has a T ２．５ or T ４ If T is higher than these predetermined temperatures, it becomes difficult to produce large glass sheets by a float method, a roll-out method, a down-draw method, or the like. ２．５ is preferably 1600°C or less, more preferably 1550°C or less, further preferably 1500°C or less, particularly preferably 1450°C or less. ４ is more preferably 1225°C or less, further preferably 1200°C or less, particularly preferably 1175°C or less, and most preferably 1150°C or less. ２．５ and T ４ Although there is no particular limitation on the lower limit of T, in order to maintain weather resistance and discoloration resistance, ２．５ is 1300℃ or more, T ４ The T of at least one of the first glass plate and the second glass plate according to this embodiment is 1000° C. or higher. ２．５ The T of at least one of the first glass plate and the second glass plate according to this embodiment is preferably 1350° C. or higher, and more preferably 1380° C. or higher. ４ The temperature is preferably 1020°C or higher, more preferably 1050°C or higher.

[0061] Furthermore, in order to enable production by the float method, the T of at least one of the first glass plate and the second glass plate according to this embodiment is ４ -T Ｌis preferably −50° C. or more. If this difference is smaller than −50° C., devitrification occurs in the glass during glass molding, which may cause problems such as a decrease in the mechanical properties of the glass and a decrease in transparency, making it difficult to obtain high-quality glass. ４ -T Ｌ is more preferably −25° C. or higher, even more preferably 0° C. or higher, and particularly preferably 20° C. or higher.

[0062] In addition, at least one of the first glass plate and the second glass plate according to this embodiment is T ｇ It is preferable that the temperature is 460°C or higher and 600°C or lower. ｇ represents the glass transition temperature. ｇ If the T of at least one of the first glass sheet and the second glass sheet according to this embodiment is within this predetermined temperature range, the glass can be bent within the range of normal manufacturing conditions. ｇ If the T is lower than 460°C, no problem occurs in formability, but the alkali content or alkaline earth content becomes too large, which tends to cause problems such as excessive thermal expansion of the glass and deterioration of weather resistance and tarnish resistance. ｇ If the T of at least one of the first glass sheet and the second glass sheet according to this embodiment is lower than 460°C, the glass may be devitrified in the forming temperature range and may not be able to be formed. ｇ is more preferably 480°C or higher, further preferably 490°C or higher, and particularly preferably 500°C or higher. ｇ If T is too high, a high temperature is required during glass bending, making manufacturing difficult. ｇ is more preferably 595°C or less, further preferably 590°C or less, particularly preferably 585°C or less, and most preferably 580°C or less. ｇ can be measured using TMA according to the standard of JIS R3103-3 (2001).

[0063] (Visible Light Transmittance: Tv) At least one of the first glass plate and the second glass plate according to this embodiment preferably has a visible light transmittance Tv of 75% or more, calculated by measuring the transmittance with a spectrophotometer using a D65 light source in accordance with the provisions of ISO-9050:2003 when converted to a thickness of 2.00 mm. A Tv of 75% or more provides excellent transparency, making it suitable for use as a windshield or door glass for a vehicle. Tv is more preferably 78% or more, and even more preferably 80% or more. The upper limit of Tv is not particularly limited, but is, for example, 91% or less.

[0064] At least one of the first glass plate and the second glass plate according to this embodiment preferably has a low solar transmittance Te and a high visible light transmittance Tv. That is, Tv / Te is preferably 1.05 or more. When Tv / Te is 1.05 or more, the glass exhibits excellent transparency and heat-shielding properties, making it more suitable as a window glass for a vehicle. The upper limit of Tv / Te is not particularly limited, but is, for example, 1.30 or less.

[0065] (Ultraviolet transmittance: Tuv) At least one of the first glass plate and the second glass plate according to this embodiment preferably has low ultraviolet transmittance, and when converted to a thickness of 2.00 mm, the ultraviolet transmittance Tuv defined in ISO-9050:2003 is preferably 65% ​​or less. Tuv is more preferably 60% or less, even more preferably 55% or less, particularly preferably 50% or less, and most preferably 45% or less. Furthermore, Tuv is, for example, 5% or more.

[0066] When moisture is present in at least one of the first glass plate and the second glass plate according to this embodiment, T １１ and T １２ This has the effect of lowering the β-OH value, making it easier to bend the glass. Therefore, it is preferable that at least one of the first glass sheet and the second glass sheet according to this embodiment contains a certain amount of moisture. The moisture in glass can generally be expressed by a value called the β-OH value, and the β-OH value is 0.050 mm －１ More than 0.10 mm is preferable. －１More preferably, 0.15 mm or more －１ More preferably, 0.20 mm or more －１ The above is particularly preferable. β-OH can be obtained from the transmittance of the glass measured using an FT-IR (Fourier transform infrared spectrophotometer) by the following formula: β-OH=(1 / X)log １０ (T Ａ / T Ｂ ) [mm －１ ] X: Sample thickness [mm] T Ａ :Reference wave number 4000cm －１ Transmittance [%] at T Ｂ : Hydroxyl group absorption wave number 3600 cm －１ Minimum transmittance in the vicinity [%]

[0067] On the other hand, if the amount of water in the glass is too large, the network structure of the glass may be affected, and the resistance to flying stones may be deteriorated. Therefore, the β-OH value of at least one of the first glass plate and the second glass plate according to this embodiment is set to 0.70 mm －１ Preferably, 0.60 mm or less －１ More preferably, 0.50 mm or less －１ More preferably, 0.40 mm or less －１ The following are particularly preferred:

[0068] At least one of the first glass plate and the second glass plate according to this embodiment has a thickness of 2.00 mm, and when converted into a thickness of 2.00 mm, the L ＊ is preferably 84.0 or more, more preferably 86.0 or more, even more preferably 88.0 or more, and even more preferably 90.0 or more. ＊ The upper limit is not particularly limited, but is 100.0 or less.

[0069] At least one of the first glass plate and the second glass plate according to this embodiment has a thickness of 2.00 mm, and is measured using a D65 light source in accordance with JIS Z 8781-4:2003. ＊ is preferably −5.0 or more, more preferably −3.0 or more, and even more preferably −2.0 or more. ＊is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.0 or less.

[0070] Furthermore, when the thickness is converted to 2.00 mm, b defined in JIS Z 8781-4:2003 using a D65 light source ＊ is preferably −5.0 or more, more preferably −3.0 or more, and even more preferably −1.0 or more. ＊ is preferably 5.0 or less, more preferably 3.0 or less, even more preferably 2.0 or less, and particularly preferably 1.5 or less. At least one of the first glass plate and the second glass plate according to this embodiment has L ＊ , a ＊ and b ＊ When the thickness is in the above range, the glass has excellent design properties and can be suitably used as a window glass for a vehicle.

[0071] Furthermore, at least one of the first glass plate and the second glass plate according to this embodiment is C ＊ = {(a ＊ ) ２ +(b ＊ ) ２} １／２ C is calculated by ＊ is preferably 3.5 or less, more preferably 3.0 or less, even more preferably 2.5 or less, and particularly preferably 2.0 or less. ＊ The smaller the value, the lower the saturation, and the darker the color of the glass. ＊ The lower limit of is not particularly limited, but is usually 0.0 or more.

[0072] At least one of the first glass sheet and the second glass sheet according to this embodiment is preferably float glass formed by, for example, a known float process, in which a molten glass base is floated on a molten metal such as tin, and strict temperature control is used to form glass with uniform thickness and sheet width, as well as large area glass.

[0073] Alternatively, at least one of the first glass sheet and the second glass sheet according to this embodiment may be glass formed by a known roll-out method or down-draw method, or may be glass having a polished surface and a uniform thickness. Here, the down-draw method is broadly divided into a slot down-draw method and an overflow down-draw method (fusion method), and both are techniques in which molten glass is continuously allowed to flow down from a forming body to form a band-shaped glass ribbon.

[0074] The shape of at least one of the first glass plate and the second glass plate according to this embodiment is not particularly limited. ２ More than 450,000 mm is preferable. ２ More preferably, 900,000 mm or more ２ The above is even more preferable. When the area of ​​the glass sheet is within the above range, it can be adapted to various vehicle models. Furthermore, if the area of ​​the glass sheet is too large, the glass sheet becomes difficult to handle, the temperature distribution during heating becomes non-uniform, the dimensional accuracy after bending becomes poor, and so on, making bending more difficult. Therefore, at least one of the first glass sheet and the second glass sheet according to this embodiment has an area of ​​the main surface of 4,000,000 mm ２ Preferably, less than 3,500,000 mm ２ More preferably, 3,000,000 mm or less ２ The following is even more preferred:

[0075] In the laminated glass 10 of this embodiment, the total thickness of the first glass sheet 11, the second glass sheet 12, and the interlayer film 13 is preferably 4.5 mm or more. A total thickness of 4.5 mm or more ensures sufficient strength. The total thickness is more preferably 4.8 mm or more, even more preferably 5.0 mm or more, even more preferably 5.1 mm or more, particularly preferably 5.2 mm or more, and most preferably 5.3 mm or more. From the viewpoint of weight reduction, the total thickness may be 10 mm or less, preferably 9.0 mm or less, more preferably 8.0 mm or less, even more preferably 7.0 mm or less, particularly preferably 6.5 mm or less, and most preferably 6.0 mm or less. The total thickness may be, for example, 4.5 mm or more and 10 mm or less.

[0076] In the laminated glass 10 of this embodiment, the thickness of the first glass sheet 11 and the second glass sheet 12 may be constant over the entire surface, or may vary from location to location as needed, such as forming a wedge shape in which the thickness of one or both of the first glass sheet 11 and the second glass sheet 12 gradually decreases.

[0077] The first glass sheet 11 and the second glass sheet 12 may have a flat shape or a curved shape having a curvature entirely or partially. If the first glass sheet 11 and the second glass sheet 12 are curved, they may have a single-curve shape, i.e., a curved shape in only one of the vertical or horizontal directions, or a complex-curve shape, i.e., a curved shape in both the vertical and horizontal directions. If the first glass sheet 11 and the second glass sheet 12 are curved, the radius of curvature in the vertical and horizontal directions may be the same or different. If the first glass sheet 11 and the second glass sheet 12 are curved, the radius of curvature in the vertical and / or horizontal directions is preferably 1000 mm or more. The shapes of the main surfaces of the first glass sheet 11 and the second glass sheet 12 are adapted to fit the window opening of the vehicle in which they are installed.

[0078] The interlayer film 13 according to this embodiment is sandwiched between the first glass sheet 11 and the second glass sheet 12. By including the interlayer film 13, the laminated glass 10 according to this embodiment can firmly bond the first glass sheet 11 and the second glass sheet 12 together and can also absorb the impact force when flying debris strikes the glass sheets.

[0079] Various organic resins that are generally used in laminated glass for conventional vehicles can be used for the interlayer film 13. Examples of organic resins include polyethylene (PE), ethylene vinyl acetate copolymer (EVA), polypropylene (PP), polystyrene (PS), methacrylic resin (PMA), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), cellulose acetate (CA), diallyl phthalate resin (DAP), urea resin (UP), melamine resin (MF), unsaturated polyester (UP), polyvinyl butyral (PVB), and polyvinyl formalin. Examples of materials that can be used include polyvinyl alcohol (PVF), polyvinyl alcohol (PVAL), vinyl acetate resin (PVAc), ionomer (IO), polymethylpentene (TPX), polyvinylidene chloride (PVDC), polysulfone (PSF), polyvinylidene fluoride (PVDF), methacrylic-styrene copolymer resin (MS), polyarate (PAR), polyallylsulfone (PASF), polybutadiene (BR), polyethersulfone (PESF), and polyetheretherketone (PEEK). Among these, EVA and PVB are preferred from the viewpoints of transparency and adhesion, and PVB is particularly preferred because it can impart sound insulation properties.

[0080] From the viewpoints of impact force absorption and sound insulation, the thickness of the interlayer film 13 is preferably 0.300 mm or more, more preferably 0.500 mm or more, and even more preferably 0.700 mm or more. From the viewpoint of suppressing a decrease in visible light transmittance, the thickness of the interlayer film 13 is preferably 1.00 mm or less, more preferably 0.900 mm or less, and even more preferably 0.800 mm or less. The thickness of the interlayer film 13 is preferably in the range of 0.300 mm to 1.00 mm, and more preferably in the range of 0.700 mm to 0.800 mm.

[0081] The thickness of the intermediate film 13 may be constant over the entire surface, or may vary from place to place as required.

[0082] If the difference in linear expansion coefficient between the interlayer film 13 and the first glass sheet 11 or the second glass sheet 12 is large, cracks or warping may occur in the laminated glass 10 when the laminated glass 10 is produced through the heating step described below, which may result in poor appearance. Therefore, it is preferable that the difference in linear expansion coefficient between the interlayer film 13 and the first glass sheet 11 or the second glass sheet 12 is as small as possible. The difference in linear expansion coefficient between the interlayer film 13 and the first glass sheet 11 or the second glass sheet 12 may be expressed as the difference between the average linear expansion coefficients within a predetermined temperature range.

[0083] In particular, since the resin constituting the interlayer film 13 has a low glass transition point, a predetermined difference in the average linear expansion coefficient may be set within a temperature range equal to or lower than the glass transition point of the resin material. The difference in the linear expansion coefficient between the first glass sheet 11 or the second glass sheet 12 and the resin material may be set at a predetermined temperature equal to or lower than the glass transition point of the resin material.

[0084] Alternatively, an adhesive layer containing an adhesive may be used for interlayer film 13. The adhesive is not particularly limited, but examples thereof include an acrylic adhesive, a silicone adhesive, etc. When interlayer film 13 is an adhesive layer, a heating step is not required in the process of joining first glass plate 11 and second glass plate 12, and therefore the risk of the above-mentioned cracking or warping occurring is reduced.

[0085] [Other Layers] The laminated glass 10 of the present embodiment may include layers (hereinafter also referred to as "other layers") other than the first glass sheet 11, the second glass sheet 12, and the interlayer film 13, provided that the effects of the present invention are not impaired. For example, the laminated glass 10 may include a coating layer that imparts water-repellent properties, hydrophilic properties, anti-fogging properties, or the like, an infrared reflective film, or the like.

[0086] The positions at which the other layers are provided are not particularly limited, and the other layers may be provided on the surface of the laminated glass 10, or may be sandwiched between the first glass sheet 11, the second glass sheet 12, or the interlayer film 13. The laminated glass 10 of this embodiment may also include a black ceramic layer or the like arranged in a strip shape along part or all of the peripheral edge for the purpose of concealing the attachment portion to the frame or the wiring conductors.

[0087] The laminated glass 10 of this embodiment can be manufactured by a method similar to that of conventionally known laminated glass. For example, by laminating a first glass sheet 11, an interlayer film 13, and a second glass sheet 12 in this order and then subjecting them to a heating and pressurizing process, a laminated glass 10 is obtained in which the first glass sheet 11 and the second glass sheet 12 are bonded together via the interlayer film 13.

[0088] The method for manufacturing the laminated glass 10 according to this embodiment may, for example, include a step of heating and shaping the first glass sheet 11 and the second glass sheet 12, followed by a step of inserting the interlayer film 13 between the first glass sheet 11 and the second glass sheet 12 and applying heat and pressure. By going through these steps, the laminated glass 10 may be configured such that the first glass sheet 11 and the second glass sheet 12 are joined together via the interlayer film 13.

[0089] As described above, the present specification discloses the following: (1) A laminated glass having a first glass sheet, a second glass sheet, and an interlayer film sandwiched between the first glass sheet and the second glass sheet, wherein the first glass sheet and the second glass sheet are borosilicate glass, and the SiO content of the first glass sheet is expressed as % by mass on an oxide basis: ２ and the SiO content of the second glass plate ２ the difference between the content of Al in the first glass plate and that of Al in the second glass plate is 1.0 mass % or less; ２ O ３ and the Al content of the second glass plate ２ O ３ the difference between the content of B and the content of B in the first glass plate is 1.0 mass % or less, ２ O ３ and the content of B contained in the second glass plate ２ O ３a difference between the contents of MgO contained in the first glass plate and the second glass plate is 1.0% by mass or less; a difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 1.0% by mass or less; a difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 1.0% by mass or less; a difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 1.0% by mass or less; ２ The content of O and the Li contained in the second glass plate ２ the difference between the content of Na and the content of O contained in the first glass plate is 1.0 mass % or less; ２ The content of O and the Na content of the second glass plate ２ the difference between the content of K and the content of O is 1.0 mass % or less, ２ The content of O and the content of K in the second glass plate ２ the difference between the content of Fe and the content of O contained in the first glass plate is 1.0 mass % or less; ２ O ３ and the Fe content of the second glass plate ２ O ３ (2) The difference between the content of SiO contained in the first glass sheet and the content of SiO contained in the second glass sheet is 1.0 mass % or less, and the thickness t1 of the first glass sheet is 3.0 mm or more, and the thickness t2 of the second glass sheet is 1.1 mm or more. ２ and the SiO content of the second glass plate ２ the difference between the content of Al in the first glass plate and that of Al in the second glass plate is 0.6 mass % or less; ２ O ３ and the Al content of the second glass plate ２ O ３ the difference between the content of B and the content of B in the first glass plate is 0.6% by mass or less, ２ O ３ and the content of B contained in the second glass plate ２ O ３a difference between the contents of MgO contained in the first glass plate and the second glass plate is 0.6% by mass or less; a difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 0.6% by mass or less; a difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 0.6% by mass or less; a difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 0.6% by mass or less; ２ The content of O and the Li contained in the second glass plate ２ the difference between the Na content and the O content is 0.6 mass % or less; ２ The content of O and the Na content of the second glass plate ２ the difference between the content of K and the content of O is 0.6 mass % or less, ２ The content of O and the content of K in the second glass plate ２ The difference between the content of Fe and the content of O contained in the first glass plate is 0.6 mass % or less, ２ O ３ and the Fe content of the second glass plate ２ O ３(3) The laminated glass according to (1) above, wherein the difference between the content of the first glass sheet and the content of the second glass sheet is 0.6% by mass or less. (3) The laminated glass according to (1) or (2) above, wherein the ratio (t1 / t2) of the thickness t1 of the first glass sheet to the thickness t2 of the second glass sheet is 1.0 to 5.5. (4) The laminated glass according to any one of (1) to (3) above, wherein the ratio (t1 / t2) of the thickness t1 of the first glass sheet to the thickness t2 of the second glass sheet is 1.2 to 5.5. (5) The laminated glass according to any one of (1) to (4) above, wherein the thickness t2 of the second glass sheet is 1.3 mm or more. (6) The laminated glass according to any one of (1) to (5) above, wherein at least one of the first glass sheet and the second glass sheet is air-cooled tempered glass. (7) The laminated glass according to any one of (1) to (6) above, wherein at least one of the first glass sheet and the second glass sheet is chemically tempered glass. (8) The laminated glass according to any one of (1) to (7), wherein the first glass sheet is an air-cooled tempered glass and the second glass sheet is a chemically tempered glass. (9) The glass composition of at least one of the first glass sheet and the second glass sheet is, in mass % on an oxide basis, 50%≦SiO ２ ≦85% 1.0%≦Al ２ O ３ ≦15% 5.0%≦B ２ O ３ ≦20% 0.0%≦MgO≦20% 0.0%≦CaO≦20% 0.0%≦SrO≦20% 0.0%≦BaO≦20% 0.0%≦Li ２ O≦20% 0.0%≦Na ２ O≦20% 0.0%≦K ２ O≦20% 0.010%≦Fe ２ O ３ ≦5.0% 1.0%≦R′ ２ O≦20% 0.0%≦RO≦20% (wherein RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is Li ２ O, Na ２ O and K ２(10) The laminated glass according to any one of the above (1) to (8), wherein the glass composition of at least one of the first glass sheet and the second glass sheet is, in mass % on an oxide basis, 65%≦SiO ２ ≦80% 2.0%≦Al ２ O ３ ≦6.0% 10%≦B ２ O ３ ≦17% 0.0%≦MgO≦5.0% 0.0%≦CaO≦5.0% 0.0%≦SrO≦5.0% 0.0%≦BaO≦5.0% 0.0%≦Li ２ O≦5.0% 4.0%≦Na ２ O≦12% 0.0%≦K ２ O≦5.0% 0.020%≦Fe ２ O ３ ≦1.0% 5.0%≦R′ ２ O≦15% 0.0%≦RO≦5.0% (wherein RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is Li ２ O, Na ２ O and K ２ (11) The laminated glass according to any one of the above (1) to (9), wherein the glass composition of at least one of the first glass sheet and the second glass sheet is such that, in mass % on an oxide basis, 7.0%≦R' ２ The laminated glass according to (10) above, wherein O≦15%.

[0090] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[0091] <Preparation of Glass Plates (Glass 1 to Glass 17)> Raw materials were placed in a platinum crucible and melted at temperatures of 1600°C to 1700°C for 3 hours to obtain molten glass, so as to obtain the glass composition (unit: mass%) shown in Table 1. The molten glass was poured onto a carbon plate and slowly cooled. Both sides of the resulting plate glass were polished to obtain each glass plate (Glass 1 to Glass 17). Glasses 2 to 4, 9, 11, and 13 to 15 were subjected to an air-cooling tempering treatment. The air-cooling tempering treatment was performed by heating the glass in an electric furnace at the treatment temperature shown in Table 1, removing the glass from the electric furnace immediately after the glass surface reached the target temperature, and cooling it for 60 seconds at an air pressure of 3.4 kPa. The heating time was 180 seconds. Table 1 shows the results of the air-cooling tempering treatment performed on glass plates 3.1 mm thick and 45 mm square. Glass 5 was also subjected to a chemical tempering treatment. The chemical strengthening treatment was performed by immersing the glass in nitrate using the nitrate, chemical strengthening treatment temperature, and chemical strengthening treatment time shown in Table 1. The results of the chemical strengthening treatment performed on glass having a thickness of 1.5 mm and a size of 25 mm square are shown in Table 1.

[0092] Glass transition points Tg and T of Glasses 1 to 17 １１ , the average coefficient of linear expansion (CTE) at 50°C to 350°C ５０－３５０ ), density, Young's modulus, modulus of rigidity, and Poisson's ratio were measured and are shown in Table 1.

[0093] The methods for determining the values ​​shown in Table 1 are as follows: (1) Glass transition temperature Tg (°C): This is a value measured using TMA and was determined in accordance with the standard of JIS R3103-3 (2001). １１ (°C): Viscosity η, which is the standard for bending workability, is 10 １１ The temperature T11 at which the viscosity reached dPa·s was measured using a beam bending method. (3) Average coefficient of linear expansion (CTE) from 50°C to 350°C ５０－３５０ (4) Density (g / cm): Measured using a differential thermal dilatometer (TMA) and determined in accordance with JIS R3102:1995. ３(5) Young's modulus (GPa): Measured at 25°C by an ultrasonic pulse method (Olympus, DL35) based on JIS R1602:1995 "Testing method for elastic modulus of fine ceramics". (6) Shear modulus (GPa): Measured at 25°C by an ultrasonic pulse method (Olympus, DL35) based on JIS R1602:1995 "Testing method for elastic modulus of fine ceramics". (7) Poisson's ratio: Measured at 25°C by an ultrasonic pulse method (Olympus, DL35) based on JIS R1602:1995 "Testing method for elastic modulus of fine ceramics". (8) Surface compressive stress CS and compressive stress layer depth DOL: The surface compressive stress CS and the compressive stress layer depth DOL were measured using a scattered light photoelastic stress meter SLP-2000 and a glass surface stress meter FSM manufactured by Orihara Seisakusho.

[0094] The measurement results are shown in Table 1. In Table 1, "-" indicates that no entry is possible because no air-cooling or chemical strengthening treatment was performed, and blank spaces indicate that no measurement was performed.

[0095]

[0096] <Preparation of Laminated Glass (Test Examples 1 to 14)> Laminated glasses of Test Examples 1 to 14 were produced according to the following procedure. Test Examples 1 and 2 are comparative examples, and Test Examples 3 to 14 are working examples.

[0097] (Test Example 1) Glass 16 having a thickness of 2.00 mm and the composition shown in Table 1 was used as the first glass plate. Glass 17 having a thickness of 2.00 mm and the composition shown in Table 1 was used as the second glass plate. Polyvinyl butyral (PVB) having a thickness of 0.78 mm was used as the interlayer film. The first glass plate, the interlayer film, and the second glass plate were laminated in this order and subjected to a pressure bonding treatment (1 MPa, 130°C, 3 hours) using an autoclave to produce a laminated glass of Test Example 1. The laminated glass of Test Example 1 had a total thickness of 4.78 mm including the first glass plate, the second glass plate, and the interlayer film. Tables 2 and 3 show the composition differences between the first and second glass plates.

[0098] Test Examples 2 to 14 Laminated glasses of Production Examples 2 to 14 were produced in the same manner as Test Example 1, except for the points shown in Tables 2 and 3. Tables 2 and 3 also show the compositional differences between the first glass plate and the second glass plate.

[0099] [Stone-Chip Resistance] The stone-chip resistance of the laminated glass of each test example was evaluated. The evaluation method and evaluation criteria were as follows. The critical impact fracture velocity (Vcrt) of the laminated glass sheet obtained above was measured using the following procedure. <Procedure> A tungsten carbide alloy with a tip curvature radius of 200 μm, an apex angle of 120°, and a weight of 1.365 g was injected at a speed of 20 km / h or more and allowed to impact the surface of the first glass sheet. During this impact, the propagation process of a crack generated by the impact of the tungsten carbide alloy was observed from the cross section of the laminated glass using a high-speed camera. This test was performed while changing the injection velocity. When a crack generated on the surface of the first glass sheet propagated and reached the surface of the first glass sheet opposite the surface where the tungsten carbide alloy was impacted, it was judged to have cracked, and the impact velocity at that time was taken as the critical impact fracture velocity (Vcrt). Those having a critical impact fracture speed Vcrt of 30 km / h or less were rated as x (poor) in terms of stone chip resistance, and those having a critical impact fracture speed Vcrt of more than 30 km / h were rated as o (good) in terms of stone chip resistance.

[0100]

[0101]

[0102] In the laminated glasses of Test Examples 3 to 14, which are working examples, the difference between the content of each of the specified glass components contained in the first glass sheet and the content of each of the specified glass components contained in the second glass sheet was 1.0 mass% or less, which meant there was little difference in composition between the glass sheets and excellent recyclability. Furthermore, in the glasses of Test Examples 3 to 14, the first glass sheet and the second glass sheet were borosilicate glass, the thickness t1 of the first glass sheet was 3.0 mm or more, and the thickness t2 of the second glass sheet was 1.1 mm or more, so they had excellent stone chip resistance. On the other hand, in the laminated glass of Test Example 1, which is a comparative example, the difference between the content of each of the specified glass components contained in the first glass sheet and the content of each of the specified glass components contained in the second glass sheet exceeded 1.0 mass%, which resulted in poor recyclability. Furthermore, in the glass of Test Example 1, the thickness t1 of the first glass sheet was less than 3.0 mm, and the second glass sheet was not borosilicate glass, so it had poor stone chip resistance. Furthermore, in the laminated glass of Test Example 2, which is a comparative example, the difference between the content of each of the specified glass components contained in the first glass plate and the content of each of the specified glass components contained in the second glass plate exceeded 1.0 mass %, and the recyclability was poor.

[0103] Although the present invention has been described in detail with reference to specific embodiments, it will be 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. This application is based on a Japanese patent application (Patent Application No. 2023-221644) filed on December 27, 2023, the entirety of which is incorporated by reference.

[0104] 10: Laminated glass 11: First glass sheet 12: Second glass sheet 13: Interlayer film

Claims

1. A laminated glass having a first glass plate, a second glass plate, and an intermediate film sandwiched between the first glass plate and the second glass plate, wherein the first glass plate and the second glass plate are borosilicate glasses, and in terms of mass% based on oxides, ２ the difference between the content of SiO contained in the first glass plate and the content of SiO ２ contained in the second glass plate is 1.0 mass% or less, and the difference between the content of Al ２ O ３ contained in the first glass plate and the content of Al ２ O ３ contained in the second glass plate is 1.0 mass% or less, and the difference between the content of B ２ O ３ contained in the first glass plate and the content of B ２ O ３ contained in the second glass plate is 1.0 mass% or less, and the difference between the content of MgO contained in the first glass plate and the content of MgO contained in the second glass plate is 1.0 mass% or less, and the difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 1.0 mass% or less, and the difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 1.0 mass% or less, and the difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 1.0 mass% or less, and the difference between the content of Li ２ O contained in the first glass plate and the content of Li ２ O contained in the second glass plate is 1.0 mass% or less, and the difference between the content of Na ２ O contained in the first glass plate and the content of Na ２ O contained in the second glass plate is 1.0 mass% or less, and the difference between the content of K ２ O contained in the first glass plate and the content of K ２ O contained in the second glass plate is 1.0 mass% or less, and the difference between the content of Fe ２ O ３ contained in the first glass plate and the content of Fe ２ O ３ The difference from the content thereof is 1.0 mass% or less, the thickness t1 of the first glass plate is 3.0 mm or more, and the thickness t2 of the second glass plate is 1.1 mm or more, a laminated glass.

2. In terms of mass% notation based on oxides, the content of SiO ２ contained in the first glass plate and the content of SiO ２ contained in the second glass plate have a difference of 0.6 mass% or less, and the content of Al ２ O ３ contained in the first glass plate and the content of Al ２ O ３ contained in the second glass plate have a difference of 0.6 mass% or less, and the content of B ２ O ３ contained in the first glass plate and the content of B ２ O ３ contained in the second glass plate have a difference of 0.6 mass% or less, and the difference between the content of MgO contained in the first glass plate and the content of MgO contained in the second glass plate is 0.6 mass% or less, and the difference between the content of CaO contained in the first glass plate and the content of CaO contained in the second glass plate is 0.6 mass% or less, and the difference between the content of SrO contained in the first glass plate and the content of SrO contained in the second glass plate is 0.6 mass% or less, and the difference between the content of BaO contained in the first glass plate and the content of BaO contained in the second glass plate is 0.6 mass% or less, and the difference between the content of Li ２ O contained in the first glass plate and the content of Li ２ O contained in the second glass plate is 0.6 mass% or less, and the difference between the content of Na ２ O contained in the first glass plate and the content of Na ２ O contained in the second glass plate is 0.6 mass% or less, and the difference between the content of K ２ O contained in the first glass plate and the content of K ２ O contained in the second glass plate is 0.6 mass% or less, and the difference between the content of Fe ２ O ３ contained in the first glass plate and the content of Fe ２ O ３ contained in the second glass plate is 0.6 mass% or less. The laminated glass according to claim 1.

3. The ratio (t1 / t2) of the thickness t1 of the first glass plate to the thickness t2 of the second glass plate is 1.0 to 5.

5. The laminated glass according to claim 1 or 2.

4. The ratio (t1 / t2) of the thickness t1 of the first glass plate to the thickness t2 of the second glass plate is 1.2 to 5.

5. The laminated glass according to any one of claims 1 to 3.

5. The thickness t2 of the second glass plate is 1.3 mm or more. The laminated glass according to any one of claims 1 to 4.

6. At least one of the first glass plate and the second glass plate is air-cooled tempered glass. The laminated glass according to any one of claims 1 to 5.

7. At least one of the first glass plate and the second glass plate is chemically strengthened glass. The laminated glass according to any one of claims 1 to 6.

8. The first glass plate is air-cooled tempered glass and the second glass plate is chemically strengthened glass. The laminated glass according to any one of claims 1 to 7.

9. The glass composition of at least one of the first glass plate and the second glass plate is, in terms of mass% based on oxides, 50% ≤ SiO ２ ≤ 85%, 1.0% ≤ Al ２ O ３ ≤ 15%, 5.0% ≤ B ２ O ３ ≤ 20%, 0.0% ≤ MgO ≤ 20%, 0.0% ≤ CaO ≤ 20%, 0.0% ≤ SrO ≤ 20%, 0.0% ≤ BaO ≤ 20%, 0.0% ≤ Li ２ O ≤ 20%, 0.0% ≤ Na ２ O ≤ 20%, 0.0% ≤ K ２ O ≤ 20%, 0.010% ≤ Fe ２ O ３ ≤ 5.0%, 1.0% ≤ R' ２ O ≤ 20%, 0.0% ≤ RO ≤ 20% (where RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is the total content of Li ２ O, Na ２ O, and K ２ O), and is the laminated glass according to any one of claims 1 to 8.

10. The glass composition of at least one of the first glass plate and the second glass plate is, in terms of mass% based on oxides, 65% ≤ SiO ２ ≤ 80%, 2.0% ≤ Al ２ O ３ ≤ 6.0%, 10% ≤ B ２ O ３ ≤ 17%, 0.0% ≤ MgO ≤ 5.0%, 0.0% ≤ CaO ≤ 5.0%, 0.0% ≤ SrO ≤ 5.0%, 0.0% ≤ BaO ≤ 5.0%, 0.0% ≤ Li ２ O ≤ 5.0%, 4.0% ≤ Na ２ O ≤ 12%, 0.0% ≤ K ２ O ≤ 5.0%, 0.020% ≤ Fe ２ O ３ ≤ 1.0%, 5.0% ≤ R' ２ O ≤ 15%, 0.0% ≤ RO ≤ 5.0% (where RO is the total content of MgO, CaO, SrO, and BaO, and R' ２ O is the total content of Li ２ O, Na ２ O, and K ２ O), which is the laminated glass according to any one of claims 1 to 9.

11. The glass composition of at least one of the first glass plate and the second glass plate is 7.0% ≤ R' ２ O ≤ 15% in terms of mass% based on oxides, and the laminated glass according to claim 10.

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