Laminated glass

Abstract

One embodiment of the present application relates to a laminated glass having a first glass sheet, a second glass sheet, and an interlayer film interposed between the first glass sheet and the second glass sheet, the first glass sheet and the second glass sheet being borosilicate glasses, the difference between the contents of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, Li2O, Na2O, K2O, and Fe2O3 in the glass components of the first glass sheet and the second glass sheet each being 1.0 mass% or less, the thickness t1 of the first glass sheet being 3.0 mm or more, and the thickness t2 of the second glass sheet being 1.1 mm or more.

Description

Technical Field

[0001] This invention relates to laminated glass. Background Technology

[0002] From a carbon-neutral perspective, for automotive glass, the goal is to reduce its weight to improve fuel and electrical efficiency, and to increase its strength to extend product lifespan. Furthermore, it is hoped that the product will be easily recyclable after use.

[0003] Patent document 1 discloses a laminated glass that achieves both high strength and thinness, wherein the inner glass plate is a chemically strengthened glass with a compressive stress layer on its surface, and the outer glass plate is a soda-lime glass that is a physically strengthened glass with a compressive stress layer on its surface.

[0004] Patent document 2 discloses a laminated glass comprising a chemically strengthened glass plate having a thickness ranging from 0.5 mm to 1 mm and a non-chemically strengthened glass plate having a thickness ranging from 1 mm to 2.5 mm.

[0005] Patent document 3 discloses a soda-lime laminated glass, which has: a first glass plate disposed on the outdoor side and a second glass plate disposed on the indoor side, wherein the difference between the slow cooling point temperature and the softening point temperature of the first glass plate and the second glass plate is within ±5℃, and the thickness of the second glass plate is 0.5mm to 1.8mm, and the thickness of the first glass plate is 1.1 times to 1.4 times the thickness of the second glass plate.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 183381

[0009] Patent Document 2: Japanese Patent No. 5890518

[0010] Patent Document 3: Japanese Patent No. 7174262 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] The laminated glass described in Patent Document 1 consists of laminated glass with different compositions. Therefore, when the broken glass generated during the recycling of the laminated glass is mixed, there is a problem of reduced recyclability.

[0013] The laminated glass described in Patent Document 2 has a thin outer layer and uses chemically strengthened glass, which results in insufficient durability against sharp projectiles.

[0014] The laminated glass described in Patent Document 3 is made of soda-lime silicate glass, which has insufficient durability against sharp projectiles.

[0015] In view of the above-mentioned problems, the present invention aims to provide a high-strength, recyclable laminated glass.

[0016] means for solving problems

[0017] The inventors have discovered that by using borosilicate glass as the glass plate of the laminated glass, reducing the difference in glass composition content between the glass plates, and ensuring that the thickness of the glass plate is above a specified value, it is possible to provide a high-strength, recyclable laminated glass, thus completing the present invention.

[0018] That is, one embodiment of the present invention relates to a laminated glass having a first glass plate, a second glass plate, and an interlayer 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 the content of SiO2 in the first glass plate differs from that in the second glass plate by 1.0% by mass (based on oxides), the content of Al2O3 in the first glass plate differs from that in the second glass plate by 1.0% by mass, the content of B2O3 in the first glass plate differs from that in the second glass plate by 1.0% by mass, the content of MgO in the first glass plate differs from that in the second glass plate by 1.0% by mass, and the content of CaO in the first glass plate differs from that in the second glass plate by 1%. The following conditions must be met: the content of SrO in the first glass plate is less than 0% by mass, the difference between the content of SrO in the first glass plate and the content of SrO in the second glass plate is less than 1.0% by mass, the difference between the content of BaO in the first glass plate and the content of BaO in the second glass plate is less than 1.0% by mass, the difference between the content of Li2O in the first glass plate and the content of Li2O in the second glass plate is less than 1.0% by mass, the difference between the content of Na2O in the first glass plate and the content of Na2O in the second glass plate is less than 1.0% by mass, the difference between the content of K2O in the first glass plate and the content of K2O in the second glass plate is less than 1.0% by mass, the difference between the content of Fe2O3 in the first glass plate and the content of Fe2O3 in the second glass plate is less than 1.0% by mass, 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.

[0019] Invention Effects

[0020] According to embodiments of the present invention, it is possible to provide high-strength, recyclable laminated glass. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of an example of laminated glass according to one embodiment of the present invention. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described in detail. Furthermore, in the following drawings, components and parts that perform the same function are sometimes labeled with the same symbols, and repeated descriptions are sometimes omitted or simplified. Also, the embodiments shown in the drawings are schematic for the purpose of clearly illustrating the present invention and do not necessarily represent the actual product dimensions or scale precisely.

[0023] In this specification, "materially free of" a certain component means that the glass does not contain any component other than unavoidable impurities, and that the component is not actively added. Specifically, it means that the content of each of these components in the glass is less than 10 ppm by mass.

[0024] like Figure 1As shown, the laminated glass 10 of this embodiment is a laminated glass having a first glass plate 11, a second glass plate 12, and an interlayer film 13 sandwiched between the first glass plate 11 and the second glass plate 12. Its characteristic is that the first glass plate 11 and the second glass plate 12 are borosilicate glasses, and the difference between the SiO2 content in the first glass plate 11 and the SiO2 content in the second glass plate 12, based on oxide mass%, is 1.0% by mass or less. The first glass plate 11 contains Al2O3... The difference between the content of MgO in the first glass plate 11 and the content of Al2O3 in the second glass plate 12 is less than 1.0% by mass; the difference between the content of B2O3 in the first glass plate 11 and the content of B2O3 in the second glass plate 12 is less than 1.0% by mass; the difference between the content of MgO in the first glass plate 11 and the content of MgO in the second glass plate 12 is less than 1.0% by mass; the difference between the content of CaO in the first glass plate 11 and the content of CaO in the second glass plate 12 is less than 1.0% by mass. The content of SrO in the first glass plate 11 is less than 1.0% by mass, the difference between the content of SrO in the first glass plate 11 and the content of SrO in the second glass plate 12 is less than 1.0% by mass, the difference between the content of BaO in the first glass plate 11 and the content of BaO in the second glass plate 12 is less than 1.0% by mass, the difference between the content of Li2O in the first glass plate 11 and the content of Li2O in the second glass plate 12 is less than 1.0% by mass, and the content of Na2O in the first glass plate 11 is less than 1.0% by mass. The difference between the Na2O content in the first glass plate 11 and the second glass plate 12 is less than 1.0% by mass; the difference between the K2O content in the first glass plate 11 and the second glass plate 12 is less than 1.0% by mass; the difference between the Fe2O3 content in the first glass plate 11 and the second glass plate 12 is less than 1.0% by mass; 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.

[0025] In this embodiment, the first and second glass plates of the laminated glass are borosilicate glass. The borosilicate glass in this embodiment refers to an oxide glass with silicon dioxide as its main component and containing boron. The boron component in the borosilicate glass is boron oxide (a general term for boron oxides such as boron trioxide (B2O3)), and the proportion of boron oxide in the glass is expressed as a conversion from B2O3. The glass composition of the borosilicate glass in the first and second glass plates will be explained later.

[0026] By using borosilicate glass for both the first and second glass plates, the laminated glass of this embodiment can suppress the increase in fuel efficiency and electrical efficiency that accompanies the increase in weight, while improving the durability of the laminated glass.

[0027] Furthermore, in the laminated glass of this embodiment, based on oxide mass%, the difference between the SiO2 content in the first glass plate and the SiO2 content in the second glass plate is 1.0% by mass or less; the difference between the Al2O3 content in the first glass plate and the Al2O3 content in the second glass plate is 1.0% by mass or less; the difference between the B2O3 content in the first glass plate and the B2O3 content in the second glass plate is 1.0% by mass or less; the difference between the MgO content in the first glass plate and the MgO content in the second glass plate is 1.0% by mass or less; the difference between the CaO content in the first glass plate and the CaO content in the second glass plate is 1.0% by mass or less; and the difference between the SrO content in the first glass plate and the SrO content in the second glass plate is 1.0% by mass or less. The differences in SrO content between the two glass plates are less than 1.0% by mass; the differences in BaO content between the first and second glass plates are less than 1.0% by mass; the differences in Li₂O content between the first and second glass plates are less than 1.0% by mass; the differences in Na₂O content between the first and second glass plates are less than 1.0% by mass; the differences in K₂O content between the first and second glass plates are less than 1.0% by mass; and the differences in Fe₂O₃ content between the first and second glass plates are less than 1.0% by mass. Therefore, the compositional deviations between the glass plates are minimal, resulting in excellent recyclability. Furthermore, since the thermal properties of the first and second glass plates are similar, in addition to excellent bendability, their refractive indices are also similar, leading to excellent visual distinguishability of the laminated glass.

[0028] The difference between the content of each of the aforementioned glass components in the first glass plate and the content of each of the aforementioned glass components 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, even more preferably 0.2% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass.

[0029] Furthermore, in the laminated glass of this embodiment, by having a thickness t1 of 3.0 mm or more for the first glass plate and a thickness t2 of 1.1 mm or more for the second glass plate, high-strength laminated glass can be provided. In particular, when the laminated glass of this embodiment is used as automotive window glass, with the glass plate facing outwards as the first glass plate and the glass plate facing inwards as the second glass plate, the thickness t1 of the first glass plate facing outwards being 3.0 mm or more provides improved durability against impacts such as flying stones, and the thickness t2 of the second glass plate facing inwards being 1.1 mm or more provides improved durability against scratches caused by objects colliding with the glass on the inside of the vehicle.

[0030] 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. Furthermore, from the viewpoint of suppressing the increase in weight of the laminated glass and facilitating bending and forming, 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.

[0031] 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. Furthermore, from the viewpoint of suppressing the increase in weight 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.

[0032] From the viewpoint of improving the durability and bending formability of laminated glass, 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. t1 / t2 is preferably 1.0 or more, more preferably 1.1 or more, further 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. With t1 / t2 being 1.0 or more, when the laminated glass of this embodiment is used as automotive window glass, and the glass plate facing outwards is used as the first glass plate and the glass plate facing inwards is used as the second glass plate, the thickness t1 of the first glass plate facing outwards is not less than the thickness t2 of the second glass plate facing inwards, thus improving durability against impacts such as flying stones. Furthermore, since t1 / t2 is 1.2 or more, when the laminated glass of this embodiment is used as automotive window glass, and the glass panel facing outwards is used as the first glass panel and the glass panel facing inwards is used as the second glass panel, the thickness t1 of the first glass panel facing outwards is greater than the thickness t2 of the second glass panel facing inwards, thus improving the durability against impacts such as flying stones.

[0033] 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. By making t1 / t2 5.5 or less, the shape control of the laminated glass after bending and forming becomes easier.

[0034] The first glass plate, the second glass plate, and the interlayer film constituting the laminated glass of this embodiment will be described in detail below.

[0035] <First Glass Plate and Second Glass Plate>

[0036] (Glass composition)

[0037] Based on oxide mass%, the glass composition of at least one of the first and second glass plates in this embodiment (hereinafter also simply referred to as the glass plate of this embodiment) is preferably as follows: 50%≤SiO2≤85% 1.0%≤Al2O3≤15% 5.0%≤B2O3≤20% 0.0%≤MgO≤20% 0.0%≤CaO≤20% 0.0%≤SrO≤20% 0.0%≤BaO≤20% 0.0%≤Li₂O≤20% 0.0%≤Na2O≤20% 0.0%≤K2O≤20% 0.010%≤Fe2O3≤5.0% 1.0%≤R'2O≤20% 0.0%≤RO≤20% (Where, RO represents the total content of MgO, CaO, SrO, and BaO, and R'2O represents the total content of Li2O, Na2O, and K2O.)

[0038] Furthermore, based on oxide-based mass percent, the glass composition of at least either the first glass plate or the second glass plate is more preferably as follows: 65%≤SiO2≤80% 2.0%≤Al2O3≤6.0% 10%≤B2O3≤17% 0.0%≤MgO≤5.0% 0.0%≤CaO≤5.0% 0.0%≤SrO≤5.0% 0.0%≤BaO≤5.0% 0.0%≤Li₂O≤5.0% 4.0%≤Na2O≤12% 0.0%≤K2O≤5.0% 0.020%≤Fe2O3≤1.0% 5.0%≤R'2O≤15% 0.0%≤RO≤5.0% (Where, RO represents the total content of MgO, CaO, SrO, and BaO, and R'2O represents the total content of Li2O, Na2O, and K2O.)

[0039] The preferred composition ranges of each component in the glass plate of this embodiment will be described below. It should be noted that, unless otherwise specified, the composition ranges of each component are expressed as a percentage by mass based on oxides.

[0040] SiO2 is a component that helps improve Young's modulus, thereby easily ensuring the strength required for applications such as vehicle manufacturing. In this embodiment, the SiO2 content is preferably 50% or more and 85% or less.

[0041] By having a SiO2 content of 50% or more, the specific gravity of the glass can be easily reduced, and weather resistance and chemical durability can be ensured. In addition, it suppresses the increase of the average coefficient of linear expansion and suppresses the thermal cracking of the glass. The SiO2 content is more preferably 65% ​​or more, further preferably 67% or more, particularly preferably 69% or more, and most preferably 70% or more.

[0042] Furthermore, by having a SiO2 content of 85% or less, the increase in viscosity during glass melting can be suppressed, making glass manufacturing easier. In addition, the formability of vehicle window glass, especially windshields, is improved. The SiO2 content is more preferably 80% or less, further preferably 78% or less, even more preferably 76% or less, particularly preferably 75% or less, and most preferably 74% or less.

[0043] In this embodiment, the Al2O3 content is preferably 1.0% or more and 15% or less. With an Al2O3 content of 1.0% or more, tetracoordinated Al2O3 with alkali metal coordination is generated, thereby reducing non-bridging oxygen in the glass and improving weather resistance, weathering resistance, and chemical durability. Furthermore, in addition to preventing the average coefficient of linear expansion from becoming excessively large and suppressing thermal cracking of the glass, chemical strengthening treatment using ion exchange can also be performed. The Al2O3 content is more preferably 2.0% or more, further 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.

[0044] Furthermore, by using Al2O3 content of 15% or less, the increase in viscosity during glass melting can be suppressed, making glass manufacturing easier. In addition, the formability of vehicle window glass, especially windshields, is improved. The Al2O3 content is more preferably 6.0% or less, further 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.

[0045] As described above, B2O3 controls the optical properties of glass, reduces its specific gravity, and also helps to improve its strength and meltability. In this embodiment, the content of B2O3 is preferably 5.0% or more and 20% or less.

[0046] By having a B2O3 content of 5.0% or more, the optical properties of the glass can be controlled. Furthermore, it can contribute to reducing the specific gravity of the glass, increasing its strength, and improving its meltability. The B2O3 content is preferably 10% or more, more preferably 11% or more, even more preferably 12% or more, and particularly preferably 13% or more.

[0047] Furthermore, by having a B2O3 content of 20% or less, alkali elements are less likely to volatilize during the melting and forming of glass, thus suppressing the degradation of glass quality. Additionally, it improves acid and alkali resistance. More preferably, the B2O3 content is 17% or less, even more preferably 16% or less, particularly preferably 15% or less, and most preferably 14% or less.

[0048] MgO is a component that promotes the melting of glass raw materials and improves weather resistance, weathering resistance, and Young's modulus. In this embodiment, the content of MgO is preferably 0.0% or more and 20% or less. When MgO is present, from the viewpoint of improving meltability and Young's modulus, its content is more preferably 0.10% or more, further 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.

[0049] Furthermore, if the MgO content is 20% or less, the glass is less prone to devitrification, and the increase in viscosity during glass melting is suppressed, making glass manufacturing easier. In addition, the formability of vehicle window glass, especially windshields, is improved. The MgO 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.

[0050] 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 present, its content is more preferably 0.10% or more, further 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 the glass raw materials and the formability of vehicle window glass, especially windshields.

[0051] Furthermore, by keeping the CaO content at 20% or less, the increase in glass density can be avoided, brittleness can be suppressed, and strength can be maintained. More preferably, the CaO content is 5.0% or less, further preferably 4.0% or less, particularly preferably 3.0% or less, and most preferably 2.0% or less.

[0052] SrO is a component that improves the meltability of glass raw materials. On the other hand, if the specific gravity of the glass increases or it becomes less brittle, the strength of the glass may decrease; therefore, it is preferable not to actively contain SrO. In this embodiment, the content of SrO is preferably 0.0% or more and 20% or less. In this embodiment, when SrO is present, its content is more preferably 0.10% or more, further 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. As a result, the meltability of the glass raw materials and the formability of vehicle window glass, especially windshields, are improved.

[0053] Furthermore, the SrO content is preferably 20% or less. By keeping the SrO content at 20% or less, the increase in the specific gravity of the glass can be suppressed. In addition, the increase in the density of the glass can be avoided, preventing it from becoming brittle and maintaining its strength. 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.

[0054] BaO is a component that improves the meltability of glass raw materials. On the other hand, if the specific gravity of the glass increases or it becomes less brittle, the strength of the glass may decrease; therefore, it is preferable not to actively contain BaO. In this embodiment, the BaO content is preferably 0.0% or more and 20% or less. When BaO is present, its content is more preferably 0.10% or more, further 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 the glass raw materials and the formability of vehicle window glass, especially windshields.

[0055] Furthermore, the BaO content is preferably 20% or less. By keeping the BaO content at 20% or less, the increase in the specific gravity of the glass can be suppressed. In addition, the increase in the density of the glass can be avoided, preventing it from becoming brittle and maintaining its strength. 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.

[0056] Li2O is a component that significantly improves the meltability of glass by adding small amounts. Furthermore, Li2O readily increases Young's modulus and contributes to the coefficient of linear expansion of glass. In this embodiment, the Li2O content is preferably 0.0% or more and 20% or less.

[0057] By including Li2O, the viscosity of the glass is reduced, thus improving the formability of vehicle window glass, especially windshields. In the case of Li2O in the glass plate of this embodiment, the content is preferably 0.20% or more, more preferably 0.50% or more, further preferably 0.70% or more, particularly preferably 1.0% or more, and most preferably 1.2% or more.

[0058] By using a Li₂O content of 20% or less, devitrification or phase separation during glass manufacturing can be suppressed, making the manufacturing process easier. Furthermore, it reduces the coefficient of linear expansion, thus suppressing thermal cracking of the glass. Additionally, since lithium is expensive, it also helps to reduce raw material costs. The Li₂O 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.

[0059] Na₂O is a component that improves the meltability of glass. Furthermore, Na₂O readily increases Young's modulus and contributes to the coefficient of linear expansion of glass. By utilizing ion exchange between Na and K ions for chemical strengthening treatment, the strength of the glass can be improved. In this embodiment, the Na₂O content is preferably 0.0% or more and 20% or less.

[0060] By including Na₂O, the viscosity of the glass decreases, thus improving the formability of vehicle window glass, especially windshields. In the case of Na₂O in the glass plate of this embodiment, the content is more preferably 4.0% or more, further preferably 4.5% or more, even more preferably 5.0% or more, even more preferably 5.5% or more, particularly preferably 6.0% or more, and most preferably 6.5% or more.

[0061] By using Na₂O content of 20% or less, the coefficient of linear expansion can be reduced, thus suppressing thermal cracking of the glass. Furthermore, the improved weather resistance makes the glass suitable for use as glass exposed to the atmosphere for extended periods, such as vehicle windows. The Na₂O content is more preferably 12% or less, even more preferably 11% or less, particularly preferably 10% or less, and most preferably 9.5% or less.

[0062] K2O is a component that improves the meltability of glass. Additionally, it increases Young's modulus and contributes to the coefficient of linear expansion of glass. In this embodiment, the K2O content is preferably 0.0% or more and 20% or less.

[0063] By including K₂O, the viscosity of the glass decreases, thus improving the formability of vehicle window glass, especially windshields. On the other hand, compared to Li₂O or Na₂O, K₂O has the effect of increasing the coefficient of linear expansion and specific gravity; therefore, adding trace amounts of K₂O is preferable compared to Li₂O or Na₂O. When K₂O is included, its 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.

[0064] By ensuring that the K2O content is 20% or less, the increase in the coefficient of linear expansion and specific gravity can be suppressed. More preferably, the K2O content is 5.0% or less; even more preferably, 4.0% or less; particularly preferably, 3.0% or less; and most preferably, 2.5% or less.

[0065] In this embodiment, SiO2 + Al2O3 + B2O3 is preferred, meaning the total content of SiO2, Al2O3, and B2O3 is 85% or more. With SiO2 + Al2O3 + B2O3 content at 85% or more, the specific gravity of the glass is reduced. Furthermore, the glass's weather resistance and weathering resistance are improved. In addition, it helps to prevent the glass's coefficient of linear expansion from becoming excessively high, thus making it suitable for use as window glass in vehicles. SiO2 + Al2O3 + B2O3 content is more preferably 87% or more, and particularly preferably 88% or more.

[0066] From the viewpoint of improving the meltability of glass raw materials and the formability of vehicle window glass, especially windshields, the SiO2+Al2O3+B2O3 content is preferably 97% or less, more preferably 95% or less, even more preferably 94% or less, even more preferably 93% or less, particularly preferably 92% or less, and most preferably 91% or less.

[0067] To impart thermal insulation, Fe2O3 may be included. The Fe2O3 content is preferably 0.010% or more and 5.0% or less. The Fe2O3 content mentioned here refers to the total iron content including FeO as an oxide of ferrous iron and Fe2O3 as an oxide of ferric iron, which is the sum of the FeO content and Fe2O3 content converted into Fe2O3.

[0068] When the Fe2O3 content is 0.010% or more, it is suitable for applications requiring thermal insulation. In this embodiment, the Fe2O3 content is preferably 0.020% or more, more preferably 0.050% or more, even more preferably 0.080% or more, even more preferably 0.10% or more, particularly preferably 0.15% or more, and most preferably 0.20% or more.

[0069] On the other hand, when the Fe2O3 content is 5.0% or less, radiative heat transfer is not hindered during manufacturing, making the raw material easy to melt. Furthermore, the light transmittance in the visible light region does not decrease, making it suitable for applications such as automotive window glass. The Fe2O3 content 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.

[0070] Furthermore, the iron ions contained in the aforementioned Fe2O3, on a mass basis, preferably satisfy 0.15 ≤ [Fe 2+ ] / ([Fe 2 + ]+[Fe 3+ The transmittance of the glass plate in the 900nm–1300nm range is ≤0.80. Therefore, the transmittance of the glass plate in this range is increased. Redox([Fe 2+ ] / ([Fe2+ ]+[Fe 3+ If the redox is too low, the heat insulation of the glass plate deteriorates. On the other hand, if the redox is too high, it may be difficult for light from infrared irradiation devices such as lasers and radar to pass through, and the absorption of ultraviolet rays may be reduced.

[0071] Here, [Fe 2+ ] and [Fe 3+ Each represents the Fe contained in the borosilicate glass of this embodiment. 2+ and Fe 3+ The content. Additionally, "[Fe 2+ ] / ([Fe 2+ ]+[Fe 3+ "])" refers to the Fe in the borosilicate glass of this embodiment. 2+ The content relative to Fe 2+ and Fe 3+ The total percentage of the content.

[0072] From the perspective of improving thermal insulation, [Fe 2+ ] / ([Fe 2+ ]+[Fe 3+ The concentration of [value] is preferably 0.17 or higher, more preferably 0.20 or higher, even more preferably 0.23 or higher, and particularly preferably 0.25 or higher. From the viewpoint of suppressing the reduction in equipment load associated with high reduction and the amber color caused by high Redox when using sulfur as a clarifying agent, it is preferably 0.75 or lower, more preferably 0.70 or lower, even more preferably 0.65 or lower, even more preferably 0.60 or lower, particularly preferably 0.55 or lower, and most preferably 0.50 or lower.

[0073] [Fe 2+ ] / ([Fe 2+ ]+[Fe 3+ The value can be obtained using the following method.

[0074] The pulverized glass was decomposed at room temperature using a mixture of hydrofluoric acid and hydrochloric acid. A certain amount of the decomposition solution was then taken into a plastic container, and hydroxylamine hydrochloride solution was added to remove Fe from the sample solution. 3+ Reduced to Fe 2+ Then, 2,2'-bipyridine solution and ammonium acetate buffer were added to make Fe 2+ Color development. The colorimetric solution was adjusted to a certain volume using ion-exchanged water, and the absorbance at a wavelength of 522 nm was measured using an absorbance spectrophotometer. Then, the concentration was calculated from a calibration curve prepared using standard solutions, thereby determining the Fe content. 2+ Quantity. Due to the Fe in the sample solution 3+ Reduced to Fe 2+ Therefore, the Fe2+ The amount refers to the "[Fe" in the sample 2+ ]+[Fe 3 + ]".

[0075] Next, the pulverized glass was decomposed at room temperature using a mixture of hydrofluoric acid and hydrochloric acid. A certain amount of the decomposition solution was then taken into a plastic container, and 2,2'-bipyridine solution and ammonium acetate buffer were quickly added, allowing only Fe to be dissolved. 2+ Color development. The colorimetric solution was adjusted to a certain volume using ion-exchanged water, and the absorbance at a wavelength of 522 nm was measured using an absorbance spectrophotometer. Then, the concentration was calculated from a calibration curve prepared using standard solutions, thereby calculating the Fe concentration. 2+ Quantity. The Fe 2+ The amount refers to the [Fe] in the sample 2+ ].

[0076] Then, based on the [Fe] calculated above 2+ ] and [Fe 2+ ]+[Fe 3+ ], calculate [Fe 2+ ] / ([Fe 2+ ]+[Fe 3+ ]).

[0077] In this embodiment, the content of R'2O, i.e., the total content of Li2O, Na2O, and K2O, is preferably 1.0% or more. It should be noted that the R'2O as a glass component is selected from at least one of Li2O, Na2O, and K2O. With the total content of R2O, i.e., the total content of Li2O, Na2O, and K2O, being 1.0% or more, the Young's modulus increases, and the viscosity of the glass decreases, improving its formability. Therefore, it is preferred for vehicle window glass, especially windshields. Furthermore, the coefficient of linear expansion can be increased within a range that prevents thermal cracking of the glass, and the strength of the glass can be improved by air-cooling strengthening treatment. The total content of R'2O, i.e., the total content of Li2O, Na2O, and K2O, is more preferably 5.0% or more, further preferably 6.0% or more, even more preferably 6.5% or more, even more preferably 7.0% or more, particularly preferably 7.5% or more, and most preferably 8.0% or more.

[0078] From the viewpoint of improving weather resistance, the total content of R'2O, namely Li2O, Na2O and K2O, 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.

[0079] Furthermore, among Li₂O, Na₂O, and K₂O, Li₂O has the smallest molecular weight, which contributes to the lightweighting of glass. In addition, it significantly contributes to reducing glass viscosity and increasing Young's modulus. Therefore, Li₂O is preferred among Li₂O, Na₂O, and K₂O. Moreover, from the viewpoint of utilizing the alkali mixing effect to improve weathering resistance, suppress phase separation, and prevent devitrification, it is preferable to contain two or more alkali metal components.

[0080] In this embodiment, the total content of RO, i.e., the content of MgO, CaO, SrO, and BaO, is preferably 0.0% or more and 20% or less. It should be noted that the RO component as a glass element is selected from at least one of MgO, CaO, SrO, and BaO. If the total content of RO, i.e., the content of MgO, CaO, SrO, and BaO, is 20% or less, the brittleness of the glass can be reduced, and the coordination number of boron can be controlled while maintaining the strength of the glass. The total content of RO, i.e., the content of MgO, CaO, SrO, and BaO, is more preferably 5.0% or less, further 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.

[0081] Furthermore, from the viewpoint of improving the formability of vehicle window glass, especially windshields, the total content of RO, namely MgO, CaO, SrO and BaO, is more preferably 0.10% or more, further 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.

[0082] The glass plate of this embodiment may contain components other than SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, Li2O, Na2O, K2O, FeO and Fe2O3 mentioned above (hereinafter also referred to as "other components"). When such components are contained, their total content is preferably 5.0% or less.

[0083] Other components include, for example, ZrO2, Y2O3, TiO2, CeO2, Nd2O5, GaO2, GeO2, MnO2, NiO, Cr2O3, V2O5, Er2O3, Au2O3, Ag2O, CuO, CdO, MoO3, SO3, Cl, F, SnO2, Sb2O3, etc., which can be metal ions or oxides. These other components may be present in amounts below 5.0% for various purposes (e.g., clarification and coloring). When the content of other components exceeds 5.0%, the SiO2 + Al2O3 + B2O3 content may be less than 85%, increasing the glass's specific gravity and decreasing its weather resistance and efflorescence resistance. Furthermore, the R2O content may be less than 5.0%, decreasing Young's modulus and increasing the glass's viscosity. 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. Er₂O₃, like Se, has the effect of making glass glow red, but as a rare element, it is expensive and, from the viewpoint of reserves, unsuitable for mass production processes such as float glass, roll forming, and downdrawing, as described later. Therefore, its content is preferably less than 0.0015%, and even more preferably substantially absent. Furthermore, to prevent environmental impact, the content of As₂O₃ and PbO is preferably less than 0.0020% each, and even more preferably substantially absent.

[0084] When the glass plate of this embodiment contains NiO, the formation of NiS may cause the glass to break; therefore, its content is preferably 0.0080% or less. More preferably, the NiO content in the glass plate of this embodiment is 0.0040% or less, more preferably 0.0020% or less, and even more preferably substantially free of NiO.

[0085] The glass plate of this embodiment may contain TiO2. TiO2 absorbs ultraviolet light, thus reducing ultraviolet transmittance (Tuv) and improving UV cutoff performance. When the glass plate of this embodiment contains TiO2, 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. TiO2 colors visible light, thus potentially reducing visible light transmittance (Tv) and changing the glass color from gray to brown. When the glass plate of this embodiment contains TiO2, its 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.

[0086] The glass plate of this embodiment may contain CeO2. CeO2 absorbs ultraviolet light, thus reducing ultraviolet transmittance (Tuv) and improving UV cutoff performance. When the glass plate of this embodiment contains CeO2, 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. CeO2 produces a solarization effect by absorbing ultraviolet light, reducing transmittance in the visible light region, and the hue of the glass may not be gray. When the glass plate of this embodiment contains CeO2, its content is preferably 0.25% or less, more preferably 0.18% or less, further preferably 0.14% or less, and particularly preferably 0.10% or less.

[0087] The glass plate in this embodiment may contain Cr2O3. Cr2O3 acts as an oxidizing agent, which can control the Fe... 2+ Amount. In the case of the glass plate in this embodiment containing Cr2O3, its content is preferably 0.0020% or more, more preferably 0.0040% or more. Since Cr2O3 colors light in the visible light region, the visible light transmittance may be reduced. In the case of the glass plate in this embodiment containing Cr2O3, its 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.

[0088] The glass plate of this embodiment may contain SnO2. SnO2 acts as a reducing agent, which can control the amount of FeO. When the glass plate of this embodiment contains SnO2, its content is preferably 0.010% or more, more preferably 0.040% or more, even more preferably 0.060% or more, and particularly preferably 0.080% or more. On the other hand, in order to suppress defects caused by SnO2 during glass manufacturing, the SnO2 content in the glass plate of this embodiment is preferably 0.40% or less, more preferably 0.30% or less, even more preferably 0.20% or less, and particularly preferably 0.15% or less.

[0089] The glass plate of this embodiment may contain SO3. SO3 acts as a clarifying agent, thus improving the bubble quality of the glass. When the glass plate of this embodiment contains SO3, its content is preferably 0.0010% or more, more preferably 0.0040% or more, even more preferably 0.0070% or more, and particularly preferably 0.015% or more. In cases of high Redox, SO3 may produce an amber color, and the glass may turn brown. When the glass plate of this embodiment contains SO3, its content is preferably 0.070% or less, more preferably 0.060% or less, even more preferably 0.050% or less, and particularly preferably 0.040% or less.

[0090] The glass plate of this embodiment may contain Cl. Cl acts as a clarifying agent, thus improving the bubble quality of the glass. When the glass plate of this embodiment contains Cl, its content is preferably 0.080% or more, more preferably 0.15% or more, further preferably 0.20% or more, particularly preferably 0.30% or more, and most preferably 0.40% or more. When the Cl content is high, the Cl2 gas volatilized from the molten glass may corrode surrounding components. When the glass plate of this embodiment contains Cl, its content is preferably 1.5% or less, more preferably 1.2% or less, further preferably 1.0% or less, and particularly preferably 0.80% or less.

[0091] <Air-cooled Enhancement>

[0092] From the perspective of improving strength, at least one of the first glass plate and the second glass plate is preferably air-cooled strengthened glass.

[0093] Here, air-cooling strengthening refers to the process of forming a compressive stress layer on the glass surface through thermal strengthening. Specifically, a uniformly heated glass sheet is rapidly cooled from a temperature near its softening point, creating compressive stress on the glass surface due to the temperature difference between the glass surface and its interior. This compressive stress is uniformly generated across the entire surface of the glass, forming a compressive stress layer of uniform depth. Compared to chemical strengthening, thermal strengthening is suitable for strengthening thick glass sheets.

[0094] <Chemical Enhancement>

[0095] From the viewpoint of improving strength, at least one of the first glass plate and the second glass plate is preferably chemically strengthened glass.

[0096] Here, chemical strengthening refers to the process of forming a compressive stress layer on the glass surface by exchanging alkali metal ions with small ionic radii (typically Li or Na ions) with larger ionic radii (typically Na or K ions) at temperatures below the glass transition temperature through ion exchange. Chemical strengthening can be implemented using known methods, such as ion exchange. In ion exchange, the glass plate is immersed in a treatment solution (e.g., molten potassium nitrate salt), exchanging ions with small ionic radii (e.g., Na ions) with larger ionic radii (e.g., K ions), thereby generating compressive stress on the glass surface.

[0097] The magnitude of the compressive stress on the glass surface (hereinafter also referred to as surface compressive stress CS) and the depth of the compressive stress layer formed on the glass surface, DOL, can be adjusted by the glass composition, chemical strengthening treatment time, and chemical strengthening treatment temperature, respectively.

[0098] In the case where the laminated glass of this embodiment is used as automotive window glass, and the glass panel facing outwards is used as the first glass panel and the glass panel facing inwards is used as the second glass panel, it is preferable that the first glass panel is air-cooled tempered glass and the second glass panel is chemically tempered glass. This is because: air-cooled tempered glass with a high DOL (dot-length) is more resistant to impacts from flying stones and other impact objects, and is therefore suitable as the first glass panel; in the event of a collision with an object inside the vehicle, the strength can be significantly improved by using chemically tempered glass, and is therefore suitable as the second glass panel.

[0099] <Other Features>

[0100] (Modulus of rigidity)

[0101] In this embodiment, the rigidity modulus of at least either the first glass plate or the second glass plate is preferably 23 GPa or higher. If the rigidity modulus is 23 GPa or higher, the glass is less prone to deformation when subjected to external force. More preferably, the rigidity modulus is 25 GPa or higher, and even more preferably, 27 GPa or higher.

[0102] In addition, when glass is subjected to external force, it deforms and consumes energy, thereby suppressing cracking. Therefore, the above-mentioned 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.

[0103] The aforementioned rigidity modulus can be, for example, above 23 GPa and below 37 GPa.

[0104] The rigidity modulus can be determined by ultrasonic pulse method based on JIS R 1602:1995 "Test method for elastic modulus of fine ceramics".

[0105] (Poisson's ratio)

[0106] In this embodiment, the Poisson's ratio of at least either the first glass plate or the second glass plate is preferably 0.25 or less. If the Poisson's ratio is 0.25 or less, the stress generated when an external force is applied to the glass can be reduced. More preferably, the Poisson's ratio is 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 and can be 0.10 or more.

[0107] The Poisson ratio mentioned above can be greater than 0.10 and less than 0.25.

[0108] Poisson's ratio can be determined by ultrasonic pulse method based on JIS R 1602:1995 "Test method for elastic modulus of fine ceramics".

[0109] (Young's modulus)

[0110] In this embodiment, the Young's modulus of at least either the first glass plate or the second glass plate 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 a Young's modulus within the above range, the glass exhibits high rigidity, making it more suitable for vehicle window glass and the like.

[0111] On the other hand, when the Young's modulus is too high, the glass is not easily deformable, and therefore may not be able to absorb the energy of a flying stone impact, resulting in glass breakage. Therefore, the Young's modulus is preferably 85 GPa or less, more preferably 83 GPa or less, further preferably 80 GPa or less, particularly preferably 79 GPa or less, and most preferably 78 GPa or less.

[0112] The aforementioned Young's modulus can be, for example, above 60 GPa and below 85 GPa.

[0113] Young's modulus can be determined by ultrasonic pulse method based on JIS R1602:1995 "Test method for elastic modulus of fine ceramics".

[0114] (T 11 )

[0115] In this embodiment, at least one of the first glass plate and the second glass plate described above preferably has a glass viscosity of 10. 11 Temperature T at [dPa·s] 11 Below 670℃. (Through T) 11 It has a temperature range of 670℃ or below, enabling bending and forming at low temperatures.

[0116] As for T 11Methods for adjusting the temperature to below 670°C include, for example, increasing the content of B2O3, R2O, and RO in the glass composition and decreasing the content of Al2O3; and including Li2O in the R2O. The T of at least either the first glass plate or the second glass plate described above in this embodiment... 11 More preferably, the temperature is below 650°C, further preferably below 640°C, even more preferably below 635°C, particularly preferably below 630°C, and most preferably below 625°C. Furthermore, considering the firing temperature of the black ceramic printed on the windshield, T... 11 Preferably, the temperature is 560°C or higher, more preferably 570°C or higher, even more preferably 575°C or higher, and especially preferably 580°C or higher.

[0117] The above T 11 For example, it can be above 560℃ and below 670℃.

[0118] T 11 The measurement can be performed using the cantilever beam bending method.

[0119] (T 12 )

[0120] In this embodiment, at least one of the first glass plate and the second glass plate described above preferably has a glass viscosity of 10. 12 Temperature T at [dPa·s] 12 Below 630℃. (Through T) 12 It can be bent and shaped at temperatures below 630℃.

[0121] As for T 12 Methods for adjusting the temperature to below 630°C include, for example, increasing the content of B2O3, R2O, and RO in the glass composition and decreasing the content of Al2O3; and including Li2O in the R2O. The T of at least either the first glass plate or the second glass plate described above in this embodiment... 12 More preferably, the temperature is below 625°C, further preferably below 620°C, even more preferably below 615°C, particularly preferably below 610°C, and most preferably below 605°C. Furthermore, considering the firing temperature of the black ceramic printed on the windshield, T... 12 Preferably, the temperature is 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.

[0122] The above T 12 For example, it can be above 540℃ and below 630℃.

[0123] T 12The measurement can be performed using the cantilever beam bending method.

[0124] (Average linear expansion coefficient)

[0125] In this embodiment, the average coefficient of linear expansion of at least either the first glass plate or the second glass plate at 50°C to 350°C is preferably 30 × 10⁻⁶. -7 / ℃ or higher. The average coefficient of linear expansion of at least one of the first glass plate and the second glass plate described in this embodiment is 30 × 10⁻⁶. -7 At temperatures above a certain temperature, in addition to facilitating air-cooling strengthening, the difference in linear expansion coefficients between the glass and black ceramics can be reduced, thus suppressing the cracking of black ceramics. To ensure that the average linear expansion coefficient is within the aforementioned range, methods can be listed such as increasing the content of B2O3, R2O, and RO in the glass composition and decreasing the content of Al2O3.

[0126] In this embodiment, the average coefficient of linear expansion of at least either the first glass plate or the second glass plate at 50°C to 350°C is more preferably 35 × 10⁻⁶. -7 / ℃ or higher, more preferably 40×10 -7 / ℃ or above, especially preferably 45×10 -7 Above / ℃, the optimal value is 50×10 -7 / ℃ or above. On the other hand, if the average coefficient of linear expansion of at least one of the first glass plate and the second glass plate in this embodiment is too large, thermal stress caused by the temperature distribution of the glass is easily generated during the glass forming process, the slow cooling process, or the windshield forming process, which may lead to thermal cracking of the glass.

[0127] Furthermore, if the average coefficient of linear expansion of at least either the first glass plate or the second glass plate in this embodiment is too large, cracking due to thermal shock may occur when used as vehicle window glass or the like. In this embodiment, the average coefficient of linear expansion of at least either the first glass plate or the second glass plate at temperatures between 50°C and 350°C is only required to be 80 × 10⁻⁶. -7 Temperatures below 75 × 10 °C are acceptable, with 75 × 10 °C being preferred. -7 Below / ℃, more preferably 70×10 -7 Below / ℃, further preferably 68×10 -7 Below / ℃, 65×10 is particularly preferred. -7 Below / ℃, the optimal value is 63×10. -7 / ℃ below.

[0128] The aforementioned average linear expansion coefficient can be, for example, 30 × 10⁻⁶. -7 / ℃ or above and 80×10 -7 / ℃ below.

[0129] The average coefficient of linear expansion can be determined using a differential thermal expansion meter (TMA) according to the standard JIS R 3102:1995.

[0130] (density)

[0131] In this embodiment, the density of at least either the first glass plate or the second glass plate is preferably 2.50 g / cm³. 3 the following.

[0132] Sodium-calcium glass, widely used as automotive glass, has a density of approximately 2.51 g / cm³. 3 However, in this embodiment, at least one of the first glass plate and the second glass plate is borosilicate glass, which has a lower density than soda-lime glass. Therefore, it is lightweight and, from the viewpoints of fuel efficiency and electrical efficiency, more suitable for use as a window glass for vehicles. More preferably, the density of at least one of the first glass plate and the second glass plate in this embodiment is 2.48 g / cm³. 3 The following is a further preferred value: 2.45 g / cm³ 3 The following is particularly preferred: 2.42 g / cm³ 3 The optimal value is 2.40 g / cm³. 3 Furthermore, from the viewpoint of improving sound insulation inside the vehicle, the density of at least either the first glass panel or the second glass panel in this embodiment is preferably 2.20 g / cm³. 3 The above, more preferably 2.22 g / cm³ 3 The above is further optimized to be 2.25 g / cm³. 3 The above, especially preferred, is 2.27 g / cm³. 3 The optimal value is 2.30 g / cm³. 3 above.

[0133] The density mentioned above can be, for example, 2.20 g / cm³. 3 Above and 2.48 g / cm 3 the following.

[0134] Density can be determined using the Archimedes method.

[0135] Furthermore, in at least one of the first glass plate and the second glass plate in this embodiment, T 2.5 Preferably, the temperature is below 1650°C. Furthermore, in at least either the first glass plate or the second glass plate of this embodiment, T4 is preferably below 1250°C, and T4-T... L Preferably, the temperature is above -50°C. It should be noted that in this specification, T... 2.5 This indicates that the glass viscosity has reached 10. 2.5The temperature at which the glass viscosity reaches 10 dPa·s, where T4 represents the glass viscosity. 4 Temperature at dPa·s, T L This indicates the liquidus temperature of the glass.

[0136] At least one of the first glass plate and the second glass plate in this embodiment is in T 2.5 When T4 exceeds these specified temperatures, it becomes difficult to manufacture large pieces of glass using methods such as float glass, roll forming, and drop drawing. In at least one of the first and second glass plates of this embodiment, T... 2.5 Preferably, the temperature is below 1600°C, more preferably below 1550°C, even more preferably below 1500°C, and particularly preferably below 1450°C. In at least one of the first glass plate and the second glass plate of this embodiment, T4 is more preferably below 1225°C, even more preferably below 1200°C, particularly preferably below 1175°C, and most preferably below 1150°C. The T4 of at least one of the first glass plate and the second glass plate of this embodiment... 2.5 There are no particular restrictions on the lower limit of T4; to maintain weather resistance and erosion resistance, T4 is typically... 2.5 The temperature is 1300°C or higher, and T4 is 1000°C or higher. The T value of at least either the first glass plate or the second glass plate in this embodiment is... 2.5 Preferably, the temperature is 1350°C or higher, more preferably 1380°C or higher. In this embodiment, the temperature T4 of at least either the first glass plate or the second glass plate is preferably 1020°C or higher, more preferably 1050°C or higher.

[0137] Furthermore, in order to enable the float glass process, at least either the first glass plate or the second glass plate of this embodiment has a T4-T... L Preferably, the temperature difference is -50°C or higher. When this difference is less than -50°C, devitrification occurs in the glass during glass forming, resulting in reduced mechanical properties and transparency, which may prevent the production of high-quality glass. The T4-T values ​​of at least either the first glass plate or the second glass plate described above in this embodiment are specified. L More preferably, the temperature is -25°C or higher; even more preferably, the temperature is 0°C or higher; and particularly preferably, the temperature is 20°C or higher.

[0138] Furthermore, at least one of the first glass plate and the second glass plate described above in this embodiment is preferably T. g The temperature range is above 460℃ and below 600℃. It should be noted that in this specification, T... g This indicates the glass transition temperature. If T... g Within this specified temperature range, glass bending can be performed under normal manufacturing conditions. The T value of at least either the first glass plate or the second glass plate described above in this embodiment...g At temperatures below 460°C, formability is not an issue, but the alkali content or alkaline earth metal content becomes excessive, easily leading to problems such as excessive thermal expansion of the glass, reduced weather resistance, and weathering resistance. Furthermore, the T value of at least either the first glass plate or the aforementioned second glass plate in this embodiment... g At temperatures below 460°C, within the forming temperature range, the glass may become devitrified and cannot be formed.

[0139] T of at least either the first glass plate or the second glass plate described above in this embodiment g More preferably, the temperature is 480°C or higher; even more preferably, 490°C or higher; and particularly preferably, 500°C or higher. On the other hand, when T... g If the temperature is too high, high temperatures are required during glass bending, making manufacturing difficult. The T value for at least either the first glass plate or the second glass plate described above in this embodiment... g More preferably, the temperature is below 595°C, even more preferably below 590°C, particularly preferably below 585°C, and most preferably below 580°C.

[0140] T g The TMA can be used to perform the test according to the JIS R3103-3 (2001) standard.

[0141] (Visible light transmittance: Tv)

[0142] In this embodiment, at least one of the first glass plate and the second glass plate described above, when the thickness is converted to 2.00 mm, preferably has a visible light transmittance Tv of 75% or more, calculated by measuring the transmittance using a spectrophotometer with a D65 light source according to ISO-9050:2003. With a Tv of 75% or more, it exhibits excellent transparency and is therefore suitable for use as a windshield or door glass for vehicles. A Tv of 78% or more is more preferred, and 80% or more is even more preferred. There is no particular upper limit to the Tv, for example, it can be 91% or less.

[0143] In this embodiment, at least one of the first glass plate and the second glass plate is preferably low in solar transmittance Te and high in visible light transmittance Tv. That is, Tv / Te is preferably 1.05 or higher. With Tv / Te of 1.05 or higher, it becomes a glass exhibiting excellent transparency and heat insulation properties, making it more suitable as a window glass for vehicles. There is no particular upper limit to Tv / Te, for example, it can be 1.30 or lower.

[0144] (UV transmittance: Tuv)

[0145] In this embodiment, at least one of the first and second glass plates preferably has low ultraviolet transmittance. When the thickness is converted to 2.00 mm, the ultraviolet transmittance (Tuv) as defined by ISO-9050:2003 is preferably 65% ​​or less. Tuv is more preferably 60% or less, further preferably 55% or less, particularly preferably 50% or less, and most preferably 45% or less. In addition, Tuv is, for example, 5% or more.

[0146] In this embodiment, at least either the first glass plate or the second glass plate has a reduced T value when moisture is present in the glass. 11 and T 12 This makes the bending and shaping of the glass easier. Therefore, at least either the first glass plate or the second glass plate in this embodiment preferably contains a certain amount of moisture. The moisture content in the glass can generally be expressed by a value such as the β-OH value, which is preferably 0.050 mm. -1 The above, more preferably 0.10mm -1 The above is further preferably 0.15mm. -1 The above, especially preferred, is 0.20mm. -1 The transmittance of the glass, measured by FT-IR (Fourier Transform Infrared Spectrophotometer), is obtained using the following formula.

[0147] β-OH = (1 / X)log 10 (T A / T B ) [mm -1 ]

[0148] X: Sample thickness [mm]

[0149] T A Reference wavenumber 4000cm -1 Transmittance [%]

[0150] T B Hydroxyl absorption wavenumber 3600cm -1 Minimum transmittance in the vicinity [%)

[0151] On the other hand, excessive water content in the glass may affect its network structure and reduce its resistance to flystone. Therefore, in this embodiment, the β-OH value of at least either the first glass plate or the second glass plate is preferably 0.70 mm. -1 Hereinafter, 0.60mm is preferred. -1 Hereinafter, 0.50mm is further preferred. -1 The following is particularly preferred: 0.40mm -1 the following.

[0152] In this embodiment, at least either the first glass plate or the second glass plate described above, when the thickness is converted to 2.00 mm, uses a D65 light source as defined in JIS Z8781-4:2003. Preferably, the value is 84.0 or higher, more preferably 86.0 or higher, even more preferably 88.0 or higher, and even more preferably 90.0 or higher. Additionally, There is no specific upper limit, but it is below 100.0.

[0153] In this embodiment, at least either the first glass plate or the second glass plate described above, when the thickness is converted to 2.00 mm, uses a D65 light source as defined in JIS Z8781-4:2003. Preferably, the value is -5.0 or higher, more preferably -3.0 or higher, and even more preferably -2.0 or higher. Additionally, Preferably, it is 2.0 or less, more preferably 1.0 or less, and even more preferably 0.0 or less.

[0154] Furthermore, when converting the thickness to 2.00mm, the D65 light source is used as defined in JIS Z8781-4:2003. Preferably, the value is -5.0 or higher, more preferably -3.0 or higher, and even more preferably -1.0 or higher. Additionally, Preferably, the glass thickness is 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 described above in this embodiment is... , and Within the aforementioned range, its excellent design makes it suitable for use as window glass in vehicles.

[0155] Furthermore, at least one of the first glass plate and the second glass plate in this embodiment is preferably... ={( ) 2 +( ) 2} 1 / 2 The result The value is 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 glass appears dark gray. Additionally, There is no particular limit to the lower limit, which is usually above 0.0.

[0156] In this embodiment, at least one of the first glass plate and the second glass plate is preferably float glass formed using a known float process. In the float process, molten glass blanks are floated on molten metal such as tin, and glass with uniform thickness and width can be formed through precise temperature control. In addition, large-area glass can also be obtained.

[0157] Alternatively, at least one of the first glass plate and the second glass plate described above in this embodiment can be glass formed using a known rolling or drawing method, or the surface can be ground to produce glass with uniform thickness. Here, the drawing method is generally divided into the flow hole drawing method and the overflow drawing method (fusion method), but both are methods of continuously flowing molten glass from the forming body to form a strip of glass.

[0158] In this embodiment, the shape of at least one of the first glass plate and the second glass plate described above is not particularly limited, but the area of ​​the main surface is preferably 250,000 mm². 2 The above, more preferably 450000mm 2 The above is further preferred to be 900000mm. 2 The above describes the process. When the area of ​​the glass plate is within the above range, it can accommodate various vehicle models. However, when the area of ​​the glass plate is too large, the processing of the glass plate becomes difficult, the temperature distribution during heating becomes uneven, and the dimensional accuracy after bending and forming deteriorates, increasing the difficulty of bending and forming. Therefore, in this embodiment, the area of ​​the main surface of at least one of the first glass plate and the second glass plate is preferably 4,000,000 mm². 2 Below, 3,500,000 mm is preferred. 2 The following is a further preferred size: 3,000,000 mm. 2 the following.

[0159] In the laminated glass 10 of this embodiment, the total thickness of the first glass plate 11, the second glass plate 12, and the interlayer film 13 is preferably 4.5 mm or more. Sufficient strength can be obtained by making this total thickness 4.5 mm or more. More preferably, this total thickness is 4.8 mm or more, further 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. Furthermore, from the viewpoint of lightweighting, this total thickness is acceptable if it is 10 mm or less, preferably 9.0 mm or less, more preferably 8.0 mm or less, further preferably 7.0 mm or less, particularly preferably 6.5 mm or less, and most preferably 6.0 mm or less.

[0160] The total thickness mentioned above can be, for example, 4.5 mm or more and 10 mm or less.

[0161] It should be noted that in the laminated glass 10 of this embodiment, the thickness of the first glass plate 11 and the second glass plate 12 can be constant throughout the entire surface, or it can be configured as a wedge shape in which the thickness of one or both of the first glass plate 11 and the second glass plate 12 gradually decreases, and can be changed according to position as needed.

[0162] The first glass plate 11 and the second glass plate 12 can be flat or curved, with curvature on the entire surface or a portion thereof. When the first glass plate 11 and the second glass plate 12 are curved, they can be either unidirectional (curving only in either the up-down or left-right direction) or bidirectional (curving in both directions). When the first glass plate 11 and the second glass plate 12 are bidirectionally curved, the radii of curvature in the up-down and left-right directions can be the same or different. When the first glass plate 11 and the second glass plate 12 are curved, the radii of curvature in the up-down and / or left-right directions are preferably 1000 mm or more. The shape of the main surface of the first glass plate 11 and the second glass plate 12 is adapted to the window opening of the vehicle to which it is mounted.

[0163] In this embodiment, the interlayer 13 is sandwiched between the first glass plate 11 and the second glass plate 12. By having the interlayer 13, the laminated glass 10 of this embodiment can firmly bond the first glass plate 11 and the second glass plate 12, and can mitigate the impact force when the shards collide with the glass plates.

[0164] As the interlayer 13, various organic resins commonly used in laminated glass for use in vehicles can be used. As organic resins, examples include polyethylene (PE), ethylene vinyl acetate copolymer (EVA), polypropylene (PP), polystyrene (PS), methacrylic acid resins (PMA), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), cellulose acetate (CA), diallyl phthalate resin (DAP), urea-formaldehyde resin (UP), melamine resin (MF), unsaturated polyester (UP), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyvinyl alcohol (PVAL), vinyl acetate resin (PVAc), ionomer (IO), polymethylpentene (TPX), polyvinylidene chloride (PVDC), polysulfone (PSF), polyvinylidene fluoride (PVDF), methacrylic acid-styrene copolymer resin (MS), polyarylate (PAR), polyarylsulfone (PASF), polybutadiene (BR), polyethersulfone (PESF), or polyether ether ketone (PEEK), etc. From the perspective of transparency and strong adhesion, EVA and PVB are preferred, especially PVB, which can provide sound insulation, and is therefore more preferred.

[0165] From the viewpoint of mitigating impact and providing sound insulation, the thickness of the interlayer membrane 13 is preferably 0.300 mm or more, more preferably 0.500 mm or more, and even more preferably 0.700 mm or more. Furthermore, from the viewpoint of suppressing the decrease in visible light transmittance, the thickness of the interlayer membrane 13 is preferably 1.00 mm or less, more preferably 0.900 mm or less, and even more preferably 0.800 mm or less. Additionally, the thickness of the interlayer membrane 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.

[0166] The thickness of the intermediate film 13 can be constant across the entire surface or can be varied according to location as needed.

[0167] It should be noted that when the difference in the coefficient of linear expansion between the interlayer film 13 and the first glass plate 11 or the second glass plate 12 is large, cracking or warping may occur in the laminated glass 10 during the heating process described later, resulting in poor appearance. Therefore, it is preferable that the difference in the coefficient of linear expansion between the interlayer film 13 and the first glass plate 11 or the second glass plate 12 be as small as possible. The difference in the coefficient of linear expansion between the interlayer film 13 and the first glass plate 11 or the second glass plate 12 can be expressed as the difference between the average coefficients of linear expansion within a specified temperature range.

[0168] In particular, since the resin constituting the intermediate film 13 has a low glass transition temperature, a predetermined difference in the average coefficient of linear expansion can be set within a temperature range below the glass transition temperature of the resin material. It should be noted that the difference in the coefficient of linear expansion between the first glass plate 11 or the second glass plate 12 and the resin material can be set based on a predetermined temperature below the glass transition temperature of the resin material.

[0169] In addition, the intermediate film 13 can be an adhesive layer containing an adhesive. There are no particular restrictions on the adhesive, such as acrylic adhesives, polysiloxane adhesives, etc.

[0170] When the intermediate film 13 is an adhesive layer, no heating process is required in the bonding process of the first glass plate 11 and the second glass plate 12, so the possibility of the above-mentioned cracking and warping is small.

[0171] [Other layers]

[0172] The laminated glass 10 of this embodiment may have layers other than the first glass plate 11, the second glass plate 12 and the interlayer film 13 (hereinafter also referred to as "other layers") without impairing the effects of the present invention. For example, it may have coatings that impart water-repellent, hydrophilic, or anti-fog functions, or infrared reflective films.

[0173] There are no particular restrictions on the location of other layers. They can be placed on the surface of the laminated glass 10, or sandwiched between the first glass plate 11, the second glass plate 12, or the intermediate film 13. In addition, in order to conceal the upper part of the frame, wiring conductors, etc., the laminated glass 10 of this embodiment may have a black ceramic layer or the like arranged in a strip on part or all of its peripheral portion.

[0174] The method for manufacturing the laminated glass 10 of this embodiment can be used in the same way as conventionally known laminated glass. For example, by sequentially stacking a first glass plate 11, an interlayer film 13, and a second glass plate 12, and then heating and pressurizing them, a laminated glass 10 with a structure in which the first glass plate 11 and the second glass plate 12 are bonded together through the interlayer film 13 can be obtained.

[0175] The manufacturing method of the laminated glass 10 in this embodiment may, for example, involve heating / forming the first glass plate 11 and the second glass plate 12 respectively, followed by inserting an interlayer film 13 between the first glass plate 11 and the second glass plate 12 and then heating and pressurizing it. By performing such a process, a laminated glass 10 with a structure in which the first glass plate 11 and the second glass plate 12 are joined together through the interlayer film 13 can be manufactured.

[0176] As stated above, the following matters are disclosed in this specification.

[0177] (1) A laminated glass, the laminated glass having a first glass plate, a second glass plate, and an interlayer sandwiched between the first glass plate and the second glass plate, wherein... The first glass plate and the second glass plate are borosilicate glass. Based on oxide mass % The difference between the SiO2 content in the first glass plate and the SiO2 content in the second glass plate is less than 1.0% by mass. The difference between the Al2O3 content in the first glass plate and the Al2O3 content in the second glass plate is less than 1.0% by mass. The difference between the B2O3 content in the first glass plate and the B2O3 content in the second glass plate is less than 1.0% by mass. The difference between the MgO content in the first glass plate and the MgO content in the second glass plate is less than 1.0% by mass. The difference between the CaO content in the first glass plate and the CaO content in the second glass plate is less than 1.0% by mass. The difference between the SrO content in the first glass plate and the SrO content in the second glass plate is less than 1.0% by mass. The difference between the BaO content in the first glass plate and the BaO content in the second glass plate is less than 1.0% by mass. The difference between the Li₂O content in the first glass plate and the Li₂O content in the second glass plate is less than 1.0% by mass. The difference between the Na2O content in the first glass plate and the Na2O content in the second glass plate is less than 1.0% by mass. The difference between the K2O content in the first glass plate and the K2O content in the second glass plate is less than 1.0% by mass. The difference between the Fe2O3 content in the first glass plate and the Fe2O3 content in the second glass plate is less than 1.0% by mass. 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.

[0178] (2) The laminated glass according to (1) above, wherein, Based on oxide mass % The difference between the SiO2 content in the first glass plate and the SiO2 content in the second glass plate is less than 0.6% by mass. The difference between the Al2O3 content in the first glass plate and the Al2O3 content in the second glass plate is less than 0.6% by mass. The difference between the B2O3 content in the first glass plate and the B2O3 content in the second glass plate is less than 0.6% by mass. The difference between the MgO content in the first glass plate and the MgO content in the second glass plate is less than 0.6% by mass. The difference between the CaO content in the first glass plate and the CaO content in the second glass plate is less than 0.6% by mass. The difference between the SrO content in the first glass plate and the SrO content in the second glass plate is less than 0.6% by mass. The difference between the BaO content in the first glass plate and the BaO content in the second glass plate is less than 0.6% by mass. The difference between the Li₂O content in the first glass plate and the Li₂O content in the second glass plate is less than 0.6% by mass. The difference between the Na2O content in the first glass plate and the Na2O content in the second glass plate is less than 0.6% by mass. The difference between the K2O content in the first glass plate and the K2O content in the second glass plate is less than 0.6% by mass. The difference between the Fe2O3 content in the first glass plate and the Fe2O3 content in the second glass plate is less than 0.6% by mass.

[0179] (3) The laminated glass according to (1) or (2) above, wherein 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.

[0180] (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 plate to the thickness t2 of the second glass plate is 1.2 to 5.5.

[0181] (5) The laminated glass as described in any one of (1) to (4) above, wherein the thickness t2 of the second glass plate is 1.3 mm or more.

[0182] (6) The laminated glass according to any one of (1) to (5) above, wherein at least one of the first glass plate and the second glass plate is air-cooled tempered glass.

[0183] (7) The laminated glass according to any one of (1) to (6) above, wherein at least one of the first glass plate and the second glass plate is chemically strengthened glass.

[0184] (8) The laminated glass according to any one of (1) to (7) above, wherein the first glass plate is air-cooled strengthened glass and the second glass plate is chemically strengthened glass.

[0185] (9) The laminated glass according to any one of (1) to (8) above, wherein, based on oxide mass%, the glass composition of at least one of the first glass plate and the second glass plate is: 50%≤SiO2≤85% 1.0%≤Al2O3≤15% 5.0%≤B2O3≤20% 0.0%≤MgO≤20% 0.0%≤CaO≤20% 0.0%≤SrO≤20% 0.0%≤BaO≤20% 0.0%≤Li₂O≤20% 0.0%≤Na2O≤20% 0.0%≤K2O≤20% 0.010%≤Fe2O3≤5.0% 1.0%≤R'2O≤20% 0.0%≤RO≤20% (Where, RO is the total content of MgO, CaO, SrO and BaO, and R'2O is the total content of Li2O, Na2O and K2O).

[0186] (10) The laminated glass according to any one of (1) to (9) above, wherein, based on oxide mass%, the glass composition of at least either the first glass plate or the second glass plate is: 65%≤SiO2≤80%, 2.0%≤Al2O3≤6.0% 10%≤B2O3≤17% 0.0%≤MgO≤5.0% 0.0%≤CaO≤5.0% 0.0%≤SrO≤5.0% 0.0%≤BaO≤5.0% 0.0%≤Li₂O≤5.0% 4.0%≤Na2O≤12% 0.0%≤K2O≤5.0% 0.020%≤Fe2O3≤1.0% 5.0%≤R'2O≤15%, 0.0%≤RO≤5.0%, (Where, RO is the total content of MgO, CaO, SrO and BaO, and R'2O is the total content of Li2O, Na2O and K2O).

[0187] (11) The laminated glass according to (10) above, wherein, based on the mass percentage of oxides, the glass composition of at least either the first glass plate or the second glass plate is 7.0% ≤ R'2O ≤ 15%.

[0188] Example

[0189] The present invention will be specifically described below with examples, but the present invention is not limited thereto.

[0190] <Preparation of Glass Plates (Glass 1 to Glass 17)>

[0191] The raw materials were added to a platinum crucible in the manner shown in Table 1 (unit: mass %) and melted at a temperature of 1600°C to 1700°C for 3 hours to produce molten glass. The molten glass was poured onto a carbon plate and slowly cooled. Both sides of the resulting plate-shaped glass were ground to obtain glass plates (glass 1 to glass 17).

[0192] It should be noted that glass 2 to glass 4, glass 9, glass 11, and glass 13 to glass 15 underwent air-cooling strengthening treatment. The air-cooling strengthening treatment was performed at the treatment temperatures shown in Table 1. The glass was heated in an electric furnace, and after the glass surface just reached the target temperature, it was removed from the furnace and cooled for 60 seconds under a wind pressure of 3.4 kPa. The heating time was 180 seconds.

[0193] It should be noted that the results of the air-cooled strengthening treatment on glass with a thickness of 3.1 mm and a size of 45 mm square are recorded in Table 1.

[0194] In addition, glass 5 underwent chemical strengthening treatment. The chemical strengthening treatment was carried out by immersing the glass in nitrate solution under the conditions of nitrate, chemical strengthening temperature, and chemical strengthening time shown in Table 1. It should be noted that the results of the chemical strengthening treatment on glass with a thickness of 1.5 mm and a size of 25 mm square are recorded in Table 1.

[0195] Determination of the glass transition temperatures Tg and T of glass 1 to glass 17 11 The average coefficient of linear expansion (CTE) between 50℃ and 350℃ 50-350 The density, Young's modulus, rigidity modulus, and Poisson's ratio are shown in Table 1.

[0196] The following shows the method for determining the values ​​shown in Table 1.

[0197] (1) Glass transition temperature Tg (°C): The values ​​measured using TMA were determined according to the JIS R3103-3 (2001) standard.

[0198] (2)T 11 (°C): The viscosity η, used as a benchmark for bending workability, was determined using the cantilever beam bending method, reaching 10. 11 Temperature T11 at dPa·s.

[0199] (3) Average linear expansion coefficient (CTE) from 50℃ to 350℃ 50-350 ): The measurements were performed using a differential thermal expansion meter (TMA) and determined according to the standard JIS R3102:1995.

[0200] (4) Density (g / cm³) 3 ): The amount of approximately 20g of bubble-free glass cut from a glass plate was determined by the Archimedes method.

[0201] (5) Young's modulus (GPa): Based on JIS R 1602:1995 "Test method for elastic modulus of fine ceramics", the elastic modulus was measured at 25°C using the ultrasonic pulse method (Olympus, DL35).

[0202] (6) Stiffness modulus (GPa): Based on JIS R 1602:1995 "Test method for elastic modulus of fine ceramics", the elastic modulus was measured at 25°C using the ultrasonic pulse method (Olympus, DL35).

[0203] (7) Poisson's ratio: Based on JIS R 1602:1995 "Test method for elastic modulus of fine ceramics", the elastic modulus was measured at 25°C using the ultrasonic pulse method (Olympus, DL35).

[0204] (8) Surface compressive stress CS and compressive stress layer depth DOL: The surface compressive stress CS and compressive stress layer depth DOL were measured using a scattered light photoelastic stress gauge SLP-2000 and a glass surface stress gauge FSM manufactured by Orihara Corporation.

[0205] The measurement results are shown in Table 1. It should be noted that in Table 1, "-" indicates that the data could not be recorded because no air-cooling or chemical enhancement treatment was performed, and an empty column indicates that no measurement was performed.

[0206] Table 1

[0207] <Fabrication of Laminated Glass (Examples 1-14)>

[0208] Laminated glass samples 1 through 14 were manufactured according to the following procedures. Samples 1 and 2 are comparative examples, and Samples 3 through 14 are exemplary examples.

[0209] (Experimental Example 1)

[0210] As the first glass plate, glass 16 with a thickness of 2.00 mm and the composition shown in Table 1 was used. As the second glass plate, glass 17 with a thickness of 2.00 mm and the composition shown in Table 1 was used. As the interlayer, polyvinyl butyral (PVB) with a thickness of 0.78 mm was used. The first glass plate, the interlayer, and the second glass plate were sequentially stacked and pressed using an autoclave (1 MPa, 130°C, 3 hours), thereby producing the laminated glass of Test Example 1. The total thickness of the first glass plate, the second glass plate, and the interlayer of the laminated glass of Test Example 1 was 4.78 mm. It should be noted that Tables 2 and 3 show the compositional differences between the first glass plate and the second glass plate.

[0211] (Experimental Examples 2 to 14)

[0212] Except for the points shown in Tables 2 and 3, laminated glass in Manufacturing Examples 2 to 14 was manufactured in the same manner as in Test Example 1. It should be noted that Tables 2 and 3 show the compositional differences between the first and second glass plates.

[0213] [Resistance to flying stones]

[0214] The resistance of laminated glass to flying stones in each test case was evaluated. The evaluation methods and criteria are as follows.

[0215] For the laminated glass plate obtained above, the critical impact fracture velocity Vcrt is determined by the following operating steps.

[0216] <Operation Steps>

[0217] A tungsten carbide superhard alloy with a front-end curvature radius of 200 μm, an apex angle of 120°, and a weight of 1.365 g was ejected at a speed of 20 km / h or higher and collided with the surface of a first glass plate. During the collision, a high-speed camera was used to observe the crack propagation process generated during the collision with the tungsten carbide superhard alloy through a cross-section of the laminated glass. This test was conducted while varying the ejection speed. When the crack generated on the surface of the first glass plate propagated and reached the surface of the first glass plate opposite to the surface that collided with the tungsten carbide superhard alloy, it was considered to have fractured. The collision speed at this point was defined as the critical impact fracture speed, Vcrt. A critical impact fracture speed Vcrt below 30 km / h was classified as "poor" (×) for flystone resistance, and a critical impact fracture speed Vcrt above 30 km / h was classified as "good" (〇).

[0218] Table 2

[0219] Table 3

[0220] In the laminated glass of Test Examples 3 to 14, which serve as embodiments, the difference between the content of each specified glass component in the first glass plate and the content of each specified glass component in the second glass plate is 1.0% by mass or less, resulting in minimal compositional deviation between the glass plates and excellent recyclability. Furthermore, in the glass of Test Examples 3 to 14, the first and second glass plates are borosilicate glass, with the thickness t1 of the first glass plate being 3.0 mm or more and the thickness t2 of the second glass plate being 1.1 mm or more, thus exhibiting excellent resistance to flystone.

[0221] On the other hand, in the laminated glass of Test Example 1, which serves as a comparative example, the difference between the content of each specified glass component in the first glass plate and the content of each specified glass component in the second glass plate is greater than 1.0% by mass, resulting in poor recyclability. Furthermore, the thickness t1 of the first glass plate in Test Example 1 is less than 3.0 mm, and the second glass plate is not borosilicate glass, thus exhibiting poor resistance to flystone.

[0222] Furthermore, the laminated glass in Test Example 2, which serves as a comparative example, also exhibits a difference of more than 1.0% by mass between the content of each specified glass component in the first glass plate and the content of each specified glass component in the second glass plate, resulting in poor recyclability.

[0223] 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 invention.

[0224] It should be noted that this application is based on Japanese patent application filed on December 27, 2023 (Japanese Patent Application No. 2023-221644), the contents of which are incorporated herein by reference.

[0225] Label Explanation

[0226] 10-Laminated Glass

[0227] 11 First Glass Plate

[0228] 12 Second glass plate

[0229] 13 Intermediate Membrane

Claims

1. A laminated glass, the laminated glass having a first glass plate, a second glass plate, and an interlayer sandwiched between the first glass plate and the second glass plate, wherein, The first glass plate and the second glass plate are borosilicate glass. Based on oxide mass % The difference between the SiO2 content in the first glass plate and the SiO2 content in the second glass plate is less than 1.0% by mass. The difference between the Al2O3 content in the first glass plate and the Al2O3 content in the second glass plate is less than 1.0% by mass. The difference between the B2O3 content in the first glass plate and the B2O3 content in the second glass plate is less than 1.0% by mass. The difference between the MgO content in the first glass plate and the MgO content in the second glass plate is less than 1.0% by mass. The difference between the CaO content in the first glass plate and the CaO content in the second glass plate is less than 1.0% by mass. The difference between the SrO content in the first glass plate and the SrO content in the second glass plate is less than 1.0% by mass. The difference between the BaO content in the first glass plate and the BaO content in the second glass plate is less than 1.0% by mass. The difference between the Li₂O content in the first glass plate and the Li₂O content in the second glass plate is less than 1.0% by mass. The difference between the Na2O content in the first glass plate and the Na2O content in the second glass plate is less than 1.0% by mass. The difference between the K2O content in the first glass plate and the K2O content in the second glass plate is less than 1.0% by mass. The difference between the Fe2O3 content in the first glass plate and the Fe2O3 content in the second glass plate is less than 1.0% by mass. 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.

2. The laminated glass according to claim 1, wherein, Based on oxide mass % The difference between the SiO2 content in the first glass plate and the SiO2 content in the second glass plate is less than 0.6% by mass. The difference between the Al2O3 content in the first glass plate and the Al2O3 content in the second glass plate is less than 0.6% by mass. The difference between the B2O3 content in the first glass plate and the B2O3 content in the second glass plate is less than 0.6% by mass. The difference between the MgO content in the first glass plate and the MgO content in the second glass plate is less than 0.6% by mass. The difference between the CaO content in the first glass plate and the CaO content in the second glass plate is less than 0.6% by mass. The difference between the SrO content in the first glass plate and the SrO content in the second glass plate is less than 0.6% by mass. The difference between the BaO content in the first glass plate and the BaO content in the second glass plate is less than 0.6% by mass. The difference between the Li₂O content in the first glass plate and the Li₂O content in the second glass plate is less than 0.6% by mass. The difference between the Na2O content in the first glass plate and the Na2O content in the second glass plate is less than 0.6% by mass. The difference between the K2O content in the first glass plate and the K2O content in the second glass plate is less than 0.6% by mass. The difference between the Fe2O3 content in the first glass plate and the Fe2O3 content in the second glass plate is less than 0.6% by mass.

3. The laminated glass according to claim 1 or 2, wherein, 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.

4. The laminated glass according to any one of claims 1 to 3, wherein, 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.

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

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

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

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

9. The laminated glass according to any one of claims 1 to 8, wherein, Based on oxide mass%, the glass composition of at least one of the first glass plate and the second glass plate is as follows: 50%≤SiO2≤85%, 1.0%≤Al2O3≤15% 5.0%≤B2O3≤20%, 0.0%≤MgO≤20% 0.0%≤CaO≤20%, 0.0%≤SrO≤20%, 0.0%≤BaO≤20% 0.0%≤Li₂O≤20% 0.0%≤Na2O≤20% 0.0%≤K2O≤20% 0.010%≤Fe2O3≤5.0% 1.0%≤R'2O≤20%, 0.0%≤RO≤20%, (Where, RO is the total content of MgO, CaO, SrO and BaO, and R'2O is the total content of Li2O, Na2O and K2O).

10. The laminated glass according to any one of claims 1 to 9, wherein, Based on oxide mass%, the glass composition of at least one of the first glass plate and the second glass plate is as follows: 65%≤SiO2≤80% 2.0%≤Al2O3≤6.0% 10%≤B2O3≤17% 0.0%≤MgO≤5.0% 0.0%≤CaO≤5.0% 0.0%≤SrO≤5.0% 0.0%≤BaO≤5.0% 0.0%≤Li₂O≤5.0% 4.0%≤Na2O≤12% 0.0%≤K2O≤5.0% 0.020%≤Fe2O3≤1.0% 5.0%≤R'2O≤15%, 0.0%≤RO≤5.0%, (Where, RO is the total content of MgO, CaO, SrO and BaO, and R'2O is the total content of Li2O, Na2O and K2O).

11. The laminated glass according to claim 10, wherein, Based on oxide mass%, the glass composition of at least either the first glass plate or the second glass plate is 7.0% ≤ R'2O ≤ 15%.

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