Alkaline borosilicate glass, curved glass, laminated glass, window pane for construction purposes and vehicle window pane

Abstract

The present invention relates to an alkali borosilicate glass having a total iron content as Fe2O3 of 0.03% or more in mol% on an oxide basis and a proportion of 3-coordinate boron, based on the total amount of 3-coordinate and 4-coordinate boron, of 61% or less, and being substantially free of Se and CoO; and which, when the thickness is converted to 2.0 mm, has a solar transmittance Te, as specified in ISO 9050:2003, of 90% or less, a predominant wavelength Dw, ​​as measured using a C standard light source as specified in JIS Z 8701:1999, of 520 to 574 nm, inclusive, and an excitation purity Pe, as measured using the C standard light source as specified in JIS Z 8701:1999, of 4.0% or less.

Description

TECHNICAL FIELD

[0001] The present invention relates to an alkali borosilicate glass, a bent glass, a laminated glass, a window pane for architectural purposes, and a vehicle window pane. STATE OF THE ART

[0002] In recent years, vehicle windshields, including automotive windshields, have been required to exhibit heat-shielding properties for energy conservation. By using glass or windshields with excellent heat-shielding properties for vehicles, temperature rises in the vehicle due to solar radiation can be prevented and air conditioning loads can be reduced.

[0003] Furthermore, gray glass is required for excellent design and visibility in vehicles. Patent Documents 1 and 2 disclose that gray glass can be obtained by adding CoO or Se as a coloring component to soda-lime silica-based glass.

[0004] In addition to the above properties, the vehicle windshield must be lightweight to reduce fuel consumption and energy consumption. Alkali borosilicate glass is an example of a glass with a specific gravity lower than that of soda-lime silica-based glass, which is a common glass for vehicle windshields.

[0005] Alkali borosilicate glass is preferred as a vehicle windshield because it has a low relative density and also excellent resistance to impact stones. Patent Document 3 discloses a vehicle windshield using alkali borosilicate glass. Furthermore, Patent Document 4 discloses that a gray glass can be obtained by adding CoO to alkali borosilicate glass. Furthermore, Patent Document 5 discloses that a gray glass can be obtained by adding Fe2O3 and Er2O3 to alkali borosilicate glass. DOCUMENT LISTPATENT DOCUMENTS Patent Document 1: JP H09-301736 A Patent Document 2: JP 2001-019470 A Patent document 3: US 2018 / 0194114 A1 Patent Document 4: JP H07-109147 A Patent Document 5: JP H04-280834 A SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0006] In Patent Documents 1, 2, and 4, Se and CoO are used to obtain a gray-colored glass. However, since these components are harmful to the human body, it is desirable to obtain a gray-colored glass without using these components.

[0007] Furthermore, in the alkali borosilicate glass disclosed in Patent Document 5, Se and CoO are not essential components, but its gray color is weak and it is insufficient in designability.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide an alkali borosilicate glass, a bent glass, and a laminated glass which have excellent heat-shielding properties, are free from harmful elements, and have excellent designability, and a window pane for construction or a vehicle window pane using the alkali borosilicate glass or the laminated glass. SOLUTION TO THE PROBLEM

[0009] The inventors of the present invention have discovered that by adjusting the proportions of three-coordinate boron and four-coordinate boron in a glass, the glass can be given a gray color. Thus, the present invention was completed.

[0010] That is, the present invention is as follows. [1] Alkali borosilicate glass, where a total iron content as Fe2O3 is 0.03% or more in mol% as oxides, a proportion of three-coordinate boron based on the total amount of three-coordinate boron and four-coordinate boron is 61% or less, the alkali borosilicate glass is essentially free of Se and CoO, when a thickness of the alkali borosilicate glass is converted to 2.0 mm, a solar transmittance Te, as specified in ISO-9050:2003, is 90% or less, a dominant wavelength Dw, ​​measured using a C standard light source specified in JIS Z 8701:1999, is 520 nm or more and 574 nm or less, and an excitation purity Pe, measured using the C standard light source specified in JIS Z 8701:1999, is 4.0% or less. [2] Alkali borosilicate glass according to [1], wherein a ratio (Tv / Te) is 1.05 or more when the thickness of the alkali borosilicate glass is converted to 2.0 mm, provided that Tv is a visible light transmittance specified in ISO-9050:2003 using a D65 light source, and Te is the sunlight transmittance specified in ISO-9050:2003. [3] Alkali borosilicate glass according to [1] or [2], wherein a visible light transmittance Tv, as specified in ISO-9050:2003, using a D65 light source is 75% or more when the thickness of the alkali borosilicate glass is converted to 2.0 mm. [4] Alkali borosilicate glass according to [1] or [2], wherein a visible light transmittance Tv, as defined in ISO-9050:2003, using a D65 light source is less than 75% when the thickness of the alkali borosilicate glass is converted to 2.0 mm. [5] The alkali borosilicate glass according to any one of [1] to [4], wherein the content of total iron as Fe2O3 is 0.040% or more and 0.60% or less in mol% as oxides. [6] The alkali borosilicate glass according to any one of [1] to [5], wherein a Young's modulus is 65 GPa or more. [7] Alkali borosilicate glass according to one of [1] to [6], wherein a temperature T 11 , where the glass viscosity is 10 11 (dPa s) is 640 °C or lower. [8] Alkali borosilicate glass according to any one of [1] to [7], comprising, in mol% as oxides: 70% ≤ SiO2 ≤ 80%; 8.0% ≤ B2O3 ≤ 20%; 1.0% ≤ Al2O3 ≤ 5.0%; 0.0% ≤ Li2O ≤ 5.0%; 2.0% ≤ Na2O ≤ 10%; 0.0% ≤ K2O ≤ 5.0%; 0.0% ≤ MgO ≤ 5.0%; 0.0% ≤ CaO ≤ 5.0%; 0.0% ≤ SrO ≤ 5.0%; 0.0% ≤ BaO ≤ 5.0%; 89% ≤ SiO2+ B2O3+ Al2O3; and 5.0% ≤ Li2O + Na2O + K2O. [9] The alkali borosilicate glass according to any one of [1] to [8], wherein the content of total iron as Fe2O3 is 0.040% or more and 0.60% or less in mol% as oxides, and a mass fraction of divalent iron as Fe2O3 in the total iron as Fe2O3 is 10% or more.

[10] Alkali borosilicate glass according to any one of [1] to [9], comprising Li2O.

[11] Bent glass comprising the alkali borosilicate glass according to any one of [1] to

[10] .

[12] Laminated glass comprising: a first glass plate; a second glass plate; and an intermediate layer arranged between the first glass plate and the second glass plate, wherein the first glass plate comprises the alkali borosilicate glass according to any one of [1] to

[10] or the bent glass according to

[11] .

[13] Laminated glass according to

[12] , wherein the second glass plate is the alkali borosilicate glass according to any one of [1] to

[10] or the bent glass according to

[11] .

[14] Laminated glass according to

[12] , wherein the second glass plate is an alkali aluminosilicate glass comprising 1.0% or more of Al2O3 in mol% as oxides.

[15] Laminated glass according to

[12] , wherein the second glass plate is an alkali aluminoborosilicate glass comprising 1.0% or more of Al2O3 and 1.0% or more of B2O3 in mol% as oxides.

[16] Laminated glass according to

[12] , wherein the second glass plate is a chemically toughened glass.

[17] Laminated glass according to

[12] , wherein the second glass plate is a soda-lime glass.

[18] A vehicle window pane comprising the alkali borosilicate glass according to any one of [1] to

[10] or the curved glass according to

[11] .

[19] A vehicle window pane comprising the laminated glass according to any one of

[12] to

[17] .

[20] A window pane for building purposes comprising the alkali borosilicate glass according to any one of [1] to

[10] or the bent glass according to

[11] . ADVANTAGEOUS EFFECTS OF THE INVENTION

[0011] According to the present invention, an alkali borosilicate glass, a bent glass, and a laminated glass having excellent heat-shielding properties, being free from harmful elements, and having excellent designability, and a window pane for construction or a vehicle window pane using the alkali borosilicate glass or the laminated glass can be provided. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a graph showing transmission spectra in Example 1, Example 6, Example 9, and Example 11. Fig. Figure 2 is a graph showing a relationship between a fraction of three-coordinate boron and a predominant wavelength Dw. Fig. Figure 3 is a graph showing a relationship between the proportion of three-coordinate boron and an excitation purity Pe. Fig.4 is a cross-sectional view of an example of a laminated glass according to an embodiment of the present invention. Fig. 5 is a schematic view showing a state where the laminated glass according to the embodiment of the present invention is used as a vehicle window glass. Fig. Figure 6 is an enlarged view of a section S in the Fig. 5. Fig. 7 is a cross-sectional view taken along the line YY in the Fig. 6. DESCRIPTION OF EMBODIMENTS

[0012] Embodiments of the present invention will be described in detail below. In the following drawings, elements and portions having the same functions may be denoted by the same reference numerals, and duplicate descriptions may be omitted or simplified. The embodiments described in the drawings are schematic for a clear illustration of the present invention and do not necessarily accurately represent a size or scale of an actual product.

[0013] In this specification, the expression that a glass is "substantially free of" a component means that the component is not contained, except for unavoidable impurities, and means that the component is not positively added. Specifically, the expression means that the content of each of these components in the glass is about 10 mol ppm or less. It should be noted that the expression "substantially free of" Se and CoO means that the content of each of these components in the glass is 1 mol ppm or less.

[0014] An alkali borosilicate glass according to the present embodiment has a total iron content, as Fe2O3, of 0.03% or more in mol% as oxides and a proportion of three-coordinate boron based on the total amount of three-coordinate boron and four-coordinate boron of 61% or less, and is substantially free of Se and CoO, and when a thickness of the alkali borosilicate glass is converted to 2.0 mm, a sunlight transmittance Te is 90% or less, a dominant wavelength Dw is 520 nm or more and 574 nm or less, and an excitation purity Pe is 4.0% or less.

[0015] In the alkali borosilicate glass according to the present embodiment (hereinafter referred to simply as glass), Fe2O3 is an essential component and is included to impart heat-shielding properties and a gray color to the glass. In the glass according to the present embodiment, the total iron content as Fe2O3 is 0.03% or more in mol% as oxides. The total iron content as Fe2O3 here refers to the total amount of iron, including FeO, which is an oxide of divalent iron, and Fe2O3, which is an oxide of trivalent iron.

[0016] When the content of total iron as Fe2O3 in the glass according to the present embodiment is 0.03% or more, reduction in visible light transmittance can be prevented, a glass suitable for a vehicle window glass and the like can be manufactured, and melting of raw materials during manufacturing is easy.

[0017] If the total iron content as Fe2O3 in the glass according to the present embodiment is less than 0.03%, the glass may not be suitable for applications requiring heat-shielding properties, and it may be necessary to use an expensive raw material with a low iron content to manufacture the glass. Furthermore, if the total iron content as Fe2O3 is less than 0.03%, heat radiation may reach a bottom surface of a melting furnace more than necessary during glass melting, and stress may be applied to the melting furnace. In the glass according to the present embodiment, the total iron content as Fe2O3 is preferably 0.040% or more, more preferably 0.060% or more, even more preferably 0.080% or more, particularly preferably 0.10% or more, and particularly preferably 0.12% or more.

[0018] In addition, iron exhibits color under visible light. Therefore, if the content of total iron as Fe2O3 is excessively large, the visible light transmittance Tv decreases, making the glass unpreferable for use in a vehicle windshield and a door glass. Moreover, the excitation purity Pe, which will be described later, increases, and the color tone of the glass is darker. As a result, the color tone of the glass no longer exhibits a gray color, which is unpreferable. In the glass according to the present embodiment, the content of total iron as Fe2O3 is preferably 0.60% or less, more preferably 0.50% or less, even more preferably 0.40% or less, particularly preferably 0.30% or less, and particularly preferably 0.25% or less. That is, in the glass according to the present embodiment, the content of total iron as Fe2O3 is, for example, 0.03% or more and 0.60% or less in mol% as oxides.

[0019] In the glass according to the present embodiment, the proportion of tricoordinate boron relative to the total amount of tricoordinate boron and tetracoordinate boron is 61% or less. The present inventors found that when the proportion of tricoordinate boron relative to the total amount of tricoordinate boron and tetracoordinate boron in the glass is 61% or less, the glass has a gray color and exhibits excellent designability even without Se and CoO.

[0020] In the glass, boron can have an oxygen coordination number of three or four. Four-coordinate boron enters the glass framework and forms a tetrahedral structure. Since the tetrahedral structure is negatively charged, the charge is compensated by alkali metal or alkaline earth metal ions. Consequently, four-coordinate boron forms a three-dimensional glass structure with low generation of non-bridging oxygen. On the other hand, three-coordinate boron is known to have non-bridging oxygen in the glass and form a planar structure, such as a ring structure (boron oxole ring).

[0021] The Fig. Fig. 1 is a diagram showing transmission spectra of glass plates in Example 1, Example 6, Example 9, and Example 11, which will be described later. The glass according to the present embodiment contains boron and iron and therefore, as shown in the transmission spectrum of Example 11 in the Fig. 1, a light absorption spectrum of Fe ions in a wavelength range of 400 nm to 650 nm exhibits a flat shape compared to a soda-lime-silica-based glass in Example 1. However, as the proportion of three-coordinate boron increases, two broad absorption bands centered at the wavelengths of 350 nm and 500 nm tend to increase, as is the case in Example 6 and Example 9. It is assumed that the broad absorption band around a wavelength of 500 nm is due to an intervalence charge transfer transition (IVCT) between Fe 2+ and Fe 3+ contained in the glass. The mechanism by which the charge transfer transition between valences between Fe 2+ and Fe 3+occurs when the proportion of three-coordinate boron increases is not clear, but it is assumed that the planar structure formed by the presence of three-coordinate boron creates a cluster structure in which the Fe atoms in the glass are close to each other, and the smaller the distance between Fe 2+ and Fe 3+ is, the more likely the charge transfer transition will occur.

[0022] As it is in the Fig. As shown in Figure 1, when the proportion of three-coordinate boron increases, the transmittance for visible light decreases sharply, which strongly influences the color tone of the glass. Fig.Figure 2 is a graph showing a relationship between the dominant wavelength Dw measured using a C standard light source specified in JIS Z 8701:1999 and the proportion of three-coordinate boron for glasses in examples and comparative examples described later. As shown in the Fig. 2, it can be seen that as the proportion of three-coordinate boron increases, that is, as the transmittance in the visible region by IVCT decreases, the dominant wavelength Dw increases and the glass has a brown color.

[0023] The Fig. Figure 3 is a graph showing a relationship between the excitation purity Pe measured using the C standard light source specified in JIS Z 8701:1999 and the proportion of three-coordinate boron for glasses in examples and comparative examples described later. As shown in the Fig.As shown in Figure 3, it can be seen that as the proportion of tricoordinate boron increases, the excitation purity Pe also increases. As described above, adjusting the proportion of tricoordinate boron is important for obtaining a glass with excellent designability, and when the proportion of tricoordinate boron is 61% or less, an achromatic gray glass with a dominant wavelength Dw of 574 nm or less and a low excitation purity Pe can be obtained.

[0024] Furthermore, as the proportion of tricoordinate boron in the glass according to the present embodiment decreases, the glass exhibits a gray color and has an increased Young's modulus, making the glass more suitable for use in vehicles and buildings or for architectural purposes. It is believed that the reason for the improvement in Young's modulus is that as the proportion of tricoordinate boron decreases and the proportion of tetracoordinate boron increases, the amount of non-bridging oxygen decreases and a high-density structure is formed, so the ionic packing density or the bond dissociation energy contributing to the Young's modulus increases.

[0025] Therefore, in the present embodiment, the proportion of the three-coordinate boron based on the total amount of the three-coordinate boron and the four-coordinate boron is 61% or less, preferably 60% or less, more preferably 59% or less, even more preferably 58% or less, particularly preferably 56% or less, and especially 54% or less.

[0026] In addition, the proportion of tricoordinate boron relative to the total amount of tricoordinate boron and tetracoordinate boron is preferably 20% or more. When the proportion of tricoordinate boron is 20% or more, the impact resistance of the glass can be improved. It is believed that the reason for the improvement in impact resistance is that as the proportion of tricoordinate boron increases, in addition to increasing the amount of non-bridging oxygen compared to tetracoordinate boron, tricoordinate boron forms a planar structure, which loosens the network structure of the glass. As a result, when an impact stone collides with the glass, the network structure of the glass is denser, collision energy is dissipated, cracks are prevented, and impact resistance is improved.The proportion of the tricoordinate boron relative to the total amount of the tricoordinate boron and the tetracoordinate boron is more preferably 30% or more, even more preferably 35% or more, even more preferably 37% or more, particularly preferably 39% or more, and especially 41% or more. That is, the proportion of the tricoordinate boron relative to the total amount of the tricoordinate boron and the tetracoordinate boron is, for example, 20% or more and 61% or less.

[0027] The proportions of three-coordinate boron and four-coordinate boron can be adjusted by adjusting the composition of the glass. In particular, they can be adjusted by appropriately adjusting the contents of an alkali metal oxide, an alkaline earth metal oxide, and Al2O3.

[0028] As described above, the four-coordinate boron is charge-supported by alkali metal ions and exists as a tetrahedral structure in the glass. This means that when an alkali metal oxide is added to the glass, it is consumed in the formation of the four-coordinate boron, and boron that is not coordinated to the alkali metal ion exists as three-coordinate boron. Therefore, by increasing the alkali metal oxide content, the proportion of three-coordinate boron in the glass decreases, and the gray color of the glass is intensified.

[0029] The content of Al2O3 must be taken into account. It is known that Al in glass has an oxygen coordination number of 4 to 6. Of these, the four-coordinate Al forms the glass structure as a tetrahedral structure. Since the four-coordinate Al is negatively charged, similar to the four-coordinate boron, the charge is compensated by alkali metal ions. The alkali metal ions present in the glass coordinate preferentially to Al rather than to boron. In particular, for example, in the case of a glass in which the content ratio of Al2O3, an alkali metal oxide, and B2O3 is 1:1:1, almost all of the alkali metal oxide is consumed in the formation of the four-coordinate Al. In the case without charge compensation by the alkali metal ions, boron exists as three-coordinate boron, so that with the above ratio, almost all of the boron in the glass exists as three-coordinate boron.

[0030] In addition, corresponding to the alkali metal oxide, the alkaline earth metal oxide also affects the coordination number of boron. In particular, since ions with lower electronegativity are more likely to react with boron, so that the amount of four-coordinate boron is increased, the proportion of four-coordinate boron tends to increase in the order of Ba, Sr, Ca and Mg, which have lower electronegativity.

[0031] Therefore, the ratios of three-coordinate boron and four-coordinate boron are adjusted by adjusting the contents of alkali metal oxide, alkaline earth metal oxide and Al2O3.

[0032] The proportions of three-coordinate boron and four-coordinate boron in the glass can be measured by nuclear magnetic resonance (NMR). Specifically, the proportions can be measured by the method set forth in the examples described later.

[0033] The glass according to the present embodiment has a sunlight transmittance Te specified in ISO-9050:2003 of 90% or less when the thickness is converted to 2.0 mm. When the Te is 90% or less, the heat shielding properties of the glass are excellent. The Te is preferably 88% or less, more preferably 86% or less, even more preferably 84% or less, particularly preferably 82% or less, and particularly preferably 80% or less. The lower limit of the Te is not particularly limited and is generally 30% or more, preferably 32% or more, more preferably 34% or more, and particularly preferably 36% or more. That is, the Te is, for example, 30% or more and 90% or less.

[0034] The glass according to the present embodiment has a dominant wavelength Dw of 520 nm or more and 574 nm or less, which is measured using a C standard light source specified in JIS Z 8701:1999. The Dw is preferably 525 nm or more, more preferably 530 nm or more, even more preferably 535 nm or more, and particularly 540 nm or more. Furthermore, the Dw is preferably 573 nm or less, more preferably 570 nm or less, even more preferably 567 nm or less, and particularly 565 nm or less.

[0035] The glass according to the present embodiment has an excitation purity Pe of 4.0% or less, measured using the C standard light source specified in JIS Z 8701:1999. The Pe is preferably 3.5% or less, more preferably 3.0% or less, even more preferably 2.5% or less, particularly preferably 2.0% or less, and particularly preferably 1.5% or less. Moreover, the lower limit of the Pe is not specifically limited and is generally 0.1% or more. That is, the Pe is, for example, 0.1% or more and 4.0% or less.

[0036] When the Dw and Pe are within the above ranges, the glass has a gray color and excellent design ability. <glaszusammensetzung>

[0037] The glass according to the present embodiment is substantially free of Se and CoO. Se and CoO are generally used as components that impart a gray color to the glass, but these components are harmful to the human body. In the present embodiment, as described above, by adjusting the proportions of tricoordinate boron and tetracoordinate boron, a gray color can be imparted to the glass, so that a glass with excellent designability can be obtained without adding Se and CoO, which are harmful to the human body.

[0038] The glass according to the present embodiment preferably contains in mol% as oxides, 70% ≤ SiO2 ≤ 80%, 8.0% ≤ B2O3 ≤ 20%, 1.0% ≤ Al2O3 ≤ 5.0%, 0.0% ≤ Li2O ≤ 5.0%, 2.0% ≤ Na2O ≤ 10%, 0.0% ≤ K2O ≤ 5.0%, 0.0% ≤ MgO ≤ 5.0%, 0.0% ≤ CaO ≤ 5.0%, 0.0% ≤ SrO ≤ 5.0%, and 0.0% ≤ BaO ≤ 5.0%, where SiO2 + B2O3 + Al2O3 ≥ 89 % and Li2O + Na2O + K2O ≥ 5.0%.

[0039] The following describes a preferred composition range of each component included in the glass according to the present embodiment. Note that the composition range of each component is expressed in mol% as oxides unless otherwise specified.

[0040] SiO2 is a component that contributes to increasing Young's modulus, making it easier to ensure the strength required for automotive applications, construction / architecture applications, and the like. In the present embodiment, the SiO2 content is preferably 70% or more and 80% or less.

[0041] When the SiO2 content is 70% or more, the relative density of the glass is slightly reduced, and weather resistance can be ensured. Furthermore, an increase in the average linear expansion coefficient is prevented, and thermal cracking of the glass is prevented. The SiO2 content is more preferably 72% or more, even more preferably 73% or more, and particularly preferably 74% or more.

[0042] Furthermore, when the SiO2 content is 80% or less, an increase in viscosity during glass melting is prevented, glass production is facilitated, and formability for a vehicle window glass, especially a windshield and the like, is improved. The SiO2 content is more preferably 79% or less, even more preferably 78% or less, and particularly preferably 77% or less.

[0043] As described above, B2O3 adjusts the optical properties of the glass, reduces the relative density of the glass, and also contributes to improving the strength and meltability of the glass. In the present embodiment, the content of B2O3 is preferably 8.0% or more and 20% or less.

[0044] When the B2O3 content is 8.0% or more, the optical properties of the glass are adjusted, and a decrease in the relative density of the glass and improvements in the strength and meltability of the glass can be facilitated. The B2O3 content is more preferably 8.5% or more, even more preferably 9.0% or more, particularly preferably 9.5% or more, and especially preferably 10% or more.

[0045] Furthermore, when B2O3 is 20% or less, alkali elements are less likely to volatilize during glass melting and forming, and a decline in glass quality can be prevented. Furthermore, acid resistance and alkali resistance can be improved. The B2O3 content is more preferably 18% or less, even more preferably 16% or less, particularly preferably 15% or less, and especially preferably 14% or less.

[0046] In the present embodiment, the content of Al2O3 is preferably 1.0% or more and 5.0% or less. When Al2O3 is 1.0% or more, four-coordinate Al2O3 coordinated with an alkali metal is generated, and thereby the amount of non-bridging oxygen in the glass is reduced, and weather resistance, stain resistance, and chemical durability are improved. Furthermore, the average linear expansion coefficient is not excessively increased, thermal cracking of the glass can be prevented, and chemical strengthening treatment using ion exchange is possible. The content of Al2O3 is more preferably 1.1% or more, even more preferably 1.3% or more, particularly preferably 1.5% or more, and particularly preferably 1.7% or more.

[0047] Furthermore, when Al2O3 is 5.0% or less, the content of the alkali metal coordinated with boron increases, and the proportion of tricoordinate boron can be reduced. Furthermore, an increase in viscosity during glass melting can be prevented, glass production is easy, and formability for a vehicle window glass, especially a windshield and the like, is improved. The content of Al2O3 is more preferably 4.5% or less, even more preferably 4.0% or less, particularly preferably 3.5% or less, and particularly preferably 3.0% or less.

[0048] Li2O is a component that improves the meltability of the glass with a small amount of addition, and a component that facilitates increasing the Young's modulus and also contributes to the linear expansion coefficient of the glass. Furthermore, Li2O can also increase the proportion of tetracoordinate boron by coordinating lithium ions with boron. In the present embodiment, the content of Li2O is preferably 0.0% or more and 5.0% or less.

[0049] When Li2O is included, glass viscosity decreases, and thus formability for a vehicle window glass, particularly a windshield and the like, is improved. In the case where Li2O is included in the glass according to the present embodiment, its content is preferably 0.50% or more, more preferably 1.0% or more, even more preferably 1.5% or more, particularly preferably 1.7% or more, and particularly preferably 2.0% or more.

[0050] When the Li2O content is 5.0% or less, devitrification or phase separation during glass production is prevented, glass production is easy, the linear expansion coefficient can be reduced, and thermal cracking of the glass can be prevented. Furthermore, the effect of reducing raw material costs is achieved because lithium raw materials are inexpensive. The Li2O content is more preferably 4.5% or less, even more preferably 4.0% or less, particularly preferably 3.5% or less, and especially preferably 3.0% or less.

[0051] Na2O is a component that improves the meltability of glass, facilitates the increase of Young's modulus, and also contributes to the linear expansion coefficient of the glass. Furthermore, Na2O can coordinate with boron to increase the proportion of tetracoordinate boron, and can also improve the strength of the glass by performing chemical strengthening treatment through ion exchange with K ions. In the present embodiment, the content of Na2O is preferably 2.0% or more and 10% or less.

[0052] When 2.0% or more of Na2O is contained, the glass viscosity decreases, and consequently, the formability of a vehicle window glass, especially a windshield, is improved. The Na2O content is more preferably 3.5% or more, even more preferably 4.0% or more, particularly preferably 4.5% or more, and especially preferably 5.0% or more.

[0053] When the Na2O content is 10% or less, the coefficient of linear expansion can be reduced and thermal cracking of the glass can be prevented. Furthermore, the stain resistance of the glass is improved, making the glass suitable for use as a glass intended to be exposed to air for a long period of time, such as a vehicle windowpane and a windowpane for construction purposes. The Na2O content is more preferably 9.0% or less, even more preferably 8.5% or less, particularly preferably 8.0% or less, and especially preferably 7.5% or less.

[0054] K2O is a component that improves the meltability of the glass and increases the Young's modulus, as well as contributing to the coefficient of linear expansion of the glass. In the present embodiment, the content of K2O is preferably 0.0% or more and 5.0% or less.

[0055] When K2O is included, glass viscosity decreases, and thus formability for a vehicle window glass, especially a windshield, is improved. Furthermore, the content of tetracoordinate boron can be increased by coordination with boron. On the other hand, since K2O has the effect of increasing the linear expansion coefficient and specific gravity compared to Li2O and Na2O, it is preferable to add a smaller amount of K2O than Li2O and Na2O. In the case where K2O is included, its content is more preferably 0.10% or more, even more preferably 0.20% or more, particularly preferably 0.30% or more, particularly preferably 0.40% or more, and particularly preferably 0.50% or more.

[0056] When the K2O content is 5.0% or less, an increase in the linear expansion coefficient or relative density can be prevented. The K2O content is more preferably 4.0% or less, even more preferably 3.5% or less, particularly preferably 3.0% or less, and especially preferably 2.5% or less.

[0057] MgO is a component that promotes melting of a glass raw material and improves weatherability and stain resistance and increases Young's modulus. Furthermore, MgO can increase the proportion of tricoordinate boron because it has high electronegativity as described above. In the present embodiment, the content of MgO is preferably 0.0% or more and 5.0% or less. In the case where MgO is contained in the glass according to the present embodiment, its content is more preferably 0.20% or more, even more preferably 0.50% or more, particularly preferably 0.70% or more, and particularly preferably 1.0% or more, in order to prevent an excessive increase in the proportion of tricoordinate boron.

[0058] Furthermore, when the MgO content is 5.0% or less, the glass is less likely to undergo devitrification, an increase in viscosity during glass melting is prevented, glass production is easy, and formability for a vehicle window glass, especially a windshield and the like, is improved. Furthermore, the proportion of tricoordinate boron can be kept low. The MgO content is more preferably 4.0% or less, even more preferably 3.5% or less, particularly preferably 3.0% or less, and particularly preferably 2.5% or less.

[0059] CaO is a component that improves the meltability of the glass raw material. Furthermore, CaO can increase the proportion of tricoordinate boron because it has high electronegativity, as described above. In the present embodiment, the content of CaO is preferably 0.0% or more and 5.0% or less. In the case where CaO is contained, its content is more preferably 0.20% or more, even more preferably 0.50% or more, particularly preferably 0.70% or more, and particularly preferably 1.0% or more. Accordingly, the meltability of the glass raw material and the formability for a vehicle window glass, particularly a windshield and the like, are improved.

[0060] Furthermore, when the CaO content is 5.0% or less, an increase in the density of the glass is avoided, deterioration in brittleness is prevented, and strength is maintained. Furthermore, the proportion of tricoordinate boron can be kept low. The CaO content is more preferably 4.0% or less, even more preferably 3.5% or less, particularly preferably 3.0% or less, and especially preferably 2.5% or less.

[0061] SrO is a component that improves the meltability of the glass raw material. Furthermore, SrO can increase the proportion of tetracoordinate boron because it has an electronegativity lower than that of Mg or Ca, as described above. On the other hand, it is preferable that SrO is not intentionally included because it may increase the relative density of the glass, increase the brittleness of the glass, and decrease the strength of the glass. In the present embodiment, when SrO is included, its content is more preferably 0.10% or more, even more preferably 0.20% or more, particularly preferably 0.30% or more, particularly preferably 0.40% or more, and particularly preferably 0.50% or more. Accordingly, the meltability of the glass raw material and the formability for a vehicle window glass, particularly a windshield and the like, are improved.

[0062] Furthermore, the content of SrO is preferably 5.0% or less. When the content of SrO is 5.0% or less, an increase in the relative density of the glass can be prevented. Furthermore, an increase in the density of the glass is avoided, deterioration of brittleness is prevented, and strength is maintained. The content of SrO is more preferably 4.0% or less, even more preferably 3.0% or less, particularly preferably 2.0% or less, and particularly preferably 1.0% or less. That is, the content of SrO is preferably 0.0% or more and 5.0% or less.

[0063] BaO is a component that improves the meltability of the glass raw material. Furthermore, BaO can increase the proportion of tetracoordinate boron because it has an electronegativity lower than that of Mg or Ca, as described above. On the other hand, it is preferable that BaO is not intentionally included because it may increase the relative density of the glass, increase the brittleness of the glass, and decrease the strength of the glass. In the case where BaO is included, its content is more preferably 0.10% or more, even more preferably 0.20% or more, particularly preferably 0.30% or more, particularly preferably 0.40% or more, and particularly preferably 0.50% or more. Accordingly, the meltability of the glass raw material and the formability for a vehicle window glass, particularly a windshield and the like, are improved.

[0064] In addition, the content of BaO is preferably 5.0% or less.

[0065] When the BaO content is 5.0% or less, an increase in the relative density of the glass can be prevented. Furthermore, an increase in the density of the glass is avoided, deterioration of brittleness is prevented, and strength is maintained. The BaO content is more preferably 4.0% or less, even more preferably 3.0% or less, particularly preferably 2.0% or less, and especially preferably 1.0% or less. That is, the BaO content is preferably 0.0% or more and 5.0% or less.

[0066] In the present embodiment, SiO2 + Al2O3 + B2O3, that is, the total of the SiO2 content, the Al2O3 content, and the B2O3 content, is preferably 89% or more. When SiO2 + Al2O3 + B2O3 is 89% or more, the relative density of the glass decreases, the weatherability and stain resistance of the glass are improved, and the linear expansion coefficient of the glass can be prevented from increasing excessively, making the glass suitable for a vehicle windowpane or a windowpane for construction purposes. SiO2 + Al2O3 + B2O3 is more preferably 90% or more, and particularly preferably 91% or more.

[0067] SiO2 + Al2O3 + B2O3 is preferably 95% or less, more preferably 94% or less, and even more preferably 93% or less, from the viewpoint of improving the meltability of the glass raw material and formability for a vehicle window glass, particularly a windshield and the like. That is, SiO2 + Al2O3 + B2O3 is preferably 89% or more and 95% or less.

[0068] In the present embodiment, the total content of Li2O, Na2O, and K2O (hereinafter sometimes referred to as R2O) is preferably 5.0% or more. When R2O is 5.0% or more, the proportion of four-coordinate boron is increased, the Young's modulus is increased, the glass viscosity decreases, and the formability is improved, making the glass preferable for use as a vehicle window glass, particularly a windshield. Moreover, the coefficient of linear expansion can be increased within a range where the glass is not subject to thermal cracking, and the strength of the glass can be improved by performing an air-cooling annealing treatment. R2O is more preferably 6.0% or more, even more preferably 6.5% or more, particularly preferably 7.0% or more, and particularly preferably 7.5% or more.

[0069] From the viewpoint of improving stain resistance and preventing the proportion of tetracoordinate boron from becoming excessive, R2O is preferably 10% or less, more preferably 9.5% or less, and particularly preferably 9.0% or less. That is, R2O is preferably 5.0% or more and 10% or less.

[0070] Furthermore, among Li2O, Na2O, and K2O, Li2O has the smallest molecular weight, which contributes to making the glass lighter. It also greatly contributes to reducing glass viscosity and increasing Young's modulus. Therefore, it is preferable to include Li2O among Li2O, Na2O, and K2O. Furthermore, in view of improving stain resistance due to the alkali mixing effect and preventing phase separation and devitrification, it is preferable to include two or more types of alkali metal components.

[0071] In the present embodiment, the total content of MgO, CaO, SrO, and BaO (hereinafter sometimes referred to as RO) is preferably 0.0% or more and 5.0% or less. When RO is 5.0% or less, the coordination number of boron can be adjusted while preventing deterioration of the brittleness of the glass and maintaining the strength of the glass. RO is more preferably 4.5% or less, even more preferably 4.0% or less, even more preferably 3.5% or less, even more preferably 3.0% or less, particularly preferably 2.5% or less, and particularly preferably 2.0% or less.

[0072] Furthermore, from the viewpoint of improving formability for a vehicle window glass, particularly a windshield, RO is more preferably 0.20% or more, even more preferably 0.50% or more, and particularly preferably 1.0% or more.

[0073] In the glass according to the present embodiment, a mass fraction (%) of divalent iron as Fe2O3 to the total iron as Fe2O3 (hereinafter referred to as Fe redox) is preferably 10% or more. The Fe redox value is a ratio of the content of Fe 2+ as Fe2O3 to the content of total iron as Fe2O3, Therefore, it is an index that represents a concentration of O2 in the glass and represents an oxidation-reduction state.

[0074] When Fe-redox in the glass according to the present embodiment is 10% or more, the content of Fe 2+ , which has an absorption band in a near-infrared region, can be increased, and as a result, the transmittance in the near-infrared region can be reduced and the heat-shielding properties can be improved. Fe-redox is more preferably 14% or more, even more preferably 16% or more, and particularly preferably 18% or more. Furthermore, Fe-redox is preferably 70% or less. When Fe-redox is 70% or less, orange coloration caused by binding of divalent negative sulfur ions (S 2- ) and trivalent iron ions (Fe 3+ ) present in the glass, a decrease in visible transmittance can be prevented, and the gray color of the glass can be maintained. Fe redox is more preferably 65% ​​or less, even more preferably 60% or less, and particularly preferably 55% or less. That is, Fe redox is preferably 10% or more and 70% or less.

[0075] With the Fe-redox, the oxidation-reduction degree of a glass melt can be controlled and adjusted based on the composition of the glass starting material, the melting temperature and the use of a reducing agent, such as coke or ammonium chloride.

[0076] The glass according to the present embodiment may contain components (hereinafter also referred to as "other components") other than the above SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, Li2O, Na2O, K2O, and Fe2O3, and in the case where the other components are contained, the total content thereof is preferably 6.0% or less.

[0077] Examples of the other components include ZrO2, Y2O3, TiO2, CeO2, Nd2O5, GaO2, GeO2, MnO2, NiO, Cr2O3, V2O5, Er2O3, Au2O3, Ag2O, CuO, CdO, MoO3, SO3, Cl, F, SnO2, and Sb2O3. The other components may be metal ions or oxides. The other components may be contained in a total amount of 6.0% or less for various purposes (e.g., refining and coloring). If the total content of the other components is more than 6.0%, SiO2 + Al2O3 + B2O3 is less than 89%, and there is a risk of increasing the specific gravity and reducing the weatherability and stain resistance of the glass. In addition, the amount of R2O is less than 5.0% and there is a risk of increasing the proportion of three-coordinate boron, decreasing the Young's modulus and increasing the glass viscosity.The content of the other components is more preferably 4.0% or less, even more preferably 2.0% or less, even more preferably 1.0% or less, particularly preferably 0.50% or less, and especially preferably 0.10% or less.

[0078] Similar to Se, Er2O3 has the effect of imparting a reddish hue to the glass, but is a rare earth element and is expensive, and in terms of supplies, it is also not suitable for use in mass production processes such as a float process, a rolling process, and a down-draw process, which will be described later. Therefore, its content is preferably less than 0.0015%, and it is more preferable that the glass be substantially free of Er2O3. To prevent adverse influences on the environment, the contents of As2O3 and PbO are each preferably less than 0.0015%, and it is more preferable that the glass be substantially free of As2O3 and PbO.

[0079] When the glass according to the present embodiment contains NiO, the formation of NiS may cause glass breakage, and therefore its content is preferably 0.0080% or less. The NiO content in the glass according to the present embodiment is more preferably 0.0040% or less, even more preferably 0.0020% or less, and it is particularly preferable that NiO is substantially not contained.

[0080] The glass according to the present embodiment may contain TiO2. TiO2 has an absorption band in an ultraviolet region and thus reduces ultraviolet transmittance Tuv and improves UV blocking performance. In the case where the glass according to the present embodiment contains TiO2, its content is preferably 0.010% or more, more preferably 0.040% or more, even more preferably 0.075% or more, and particularly preferably 0.15% or more. Since TiO2 has a color under visible light, there is a risk of a decrease in visible light transmittance Tv and a change in the color tone of the glass from gray to brown. In the case where the glass according to the present embodiment contains TiO2, its content is preferably 0.80% or less, more preferably 0.50% or less, even more preferably 0.40% or less, and particularly preferably 0.30% or less., the content of TiO2 is preferably 0.0% or more and 0.80% or less.

[0081] The glass according to the present embodiment may contain CeO2. CeO2 has an absorption band in the ultraviolet region and thus reduces the ultraviolet transmittance Tuv and improves the UV blocking ability. In the case where the glass according to the present embodiment contains CeO2, its content is preferably 0.010% or more, more preferably 0.020% or more, even more preferably 0.040% or more, and particularly preferably 0.070% or more. CeO2 absorbs ultraviolet light, causing irradiation, the transmittance in the visible region may decrease, and the color tone of the glass may no longer be a gray color. In the case where the glass according to the present embodiment contains CeO2, its content is preferably 0.25% or less, more preferably 0.18% or less, even more preferably 0.14% or less, and particularly preferably 0.10% or less., the content of CeO2 is preferably 0.0% or more and 0.25% or less.

[0082] The glass according to the present embodiment may contain Cr2O3. Cr2O3 may be used as an oxidizing agent for adjusting the amount of Fe 2+ In the case where the glass according to the present embodiment contains Cr2O3, the content thereof is preferably 0.0020% or more, and more preferably 0.0040% or more. Since Cr2O3 has a color under visible light, the transmittance to visible light can be reduced. In the case where the glass according to the present embodiment contains Cr2O3, the content thereof is preferably 0.020% or less, more preferably 0.016% or less, even more preferably 0.012% or less, and particularly preferably 0.0080% or less. That is, the content of Cr2O3 is preferably 0.0% or more and 0.020% or less.

[0083] The glass according to the present embodiment may contain SnO2. SnO2 can act as a reducing agent for adjusting an amount of FeO. In the case where the glass according to the present embodiment contains SnO2, the content thereof 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 prevent defects derived from SnO2 during glass production, the content of SnO2 in the glass according to the present 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. That is, the content of SnO2 is preferably 0.0% or more and 0.40% or less.

[0084] The glass according to the present embodiment may contain SO3. SO3 acts as a refining agent and therefore improves the bubble quality of the glass. In the case where the glass according to the present 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 the case where Fe redox is large, SO3 may cause orange discoloration and turn the glass brown. In the case where the glass according to the present 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. That is, the content of SO3 is preferably 0.0% or more and 0.070% or less.

[0085] The glass according to the present embodiment may contain Cl. Cl acts as a refining agent and therefore improves the bubble quality of the glass. In the case where the glass according to the present embodiment contains Cl, its content is preferably 0.080% or more, more preferably 0.15% or more, even more preferably 0.20% or more, particularly preferably 0.30% or more, and particularly preferably 0.40% or more. If the content of Cl is excessively large, Cl2 gas volatilized from the glass melt may corrode surrounding elements. In the case where the glass according to the present embodiment contains Cl, its content is preferably 1.5% or less, more preferably 1.2% or less, even more preferably 1.0% or less, and particularly preferably 0.80% or less. That is, the content of Cl is preferably 0.0% or more and 1.5% or less. <Weitere Eigenschaften> (Visible light transmittance: Tv)

[0086] In the glass according to the present embodiment, when the thickness is converted to 2.0 mm, the visible light transmittance Tv calculated by measuring the transmittance with a spectrophotometer using a D65 light source according to the specifications in ISO-9050:2003 is preferably 75% or more. When Tv is 75% or more, the glass has excellent transparency and is therefore suitable for use as a vehicle windshield and door glass. Tv is more preferably 78% or more, and even more preferably 80% or more. The upper limit of Tv is not particularly limited and is, for example, 91% or less. That is, Tv is, for example, 75% or more and 91% or less.

[0087] In the glass according to the present embodiment, the absorption of visible light can be adjusted by adjusting the proportions of tricoordinate boron and tetracoordinate boron as described above, and therefore, the glass according to the present embodiment can also be used as a vehicle rear glass. When the glass according to the present embodiment is used as a vehicle rear glass, the Tv of the glass is preferably less than 75%, more preferably 72% or less, and even more preferably 70% or less.

[0088] The glass according to the present embodiment preferably has low sunlight transmittance Te and high visible light transmittance Tv. That is, Tv / Te is preferably 1.05 or more. When Tv / Te is 1.05 or more, a glass having excellent transparency and excellent heat-shielding properties is obtained, which is more suitable for use as a vehicle windowpane or a windowpane for construction purposes. The upper limit of Tv / Te is not particularly limited and is, for example, 1.30 or less. That is, Tv / Te is, for example, 1.05 or more and 1.30 or less. (Ultraviolet transmittance: Tuv)

[0089] The glass according to the present embodiment preferably has low ultraviolet transmittance, and when the thickness is converted to 2.0 mm, the ultraviolet transmittance Tuv specified in ISO-9050:2003 is preferably 65% ​​or less. Tuv is more preferably 60% or less, even more preferably 55% or less, particularly preferably 50% or less, and particularly preferably 45% or less. Moreover, Tuv is, for example, 5% or more. That is, Tuv is, for example, 5% or more and 65% or less. (Young's modulus)

[0090] The Young's modulus of the glass according to the present embodiment is preferably 65 GPa or more, more preferably 68 GPa or more, even more preferably 70 GPa or more, and particularly preferably 72 GPa or more. When the Young's modulus is within the above range, the glass has high rigidity and is suitable for use as a vehicle window glass and the like.

[0091] On the other hand, if the Young's modulus is too large, the glass is less likely to deform and may therefore not be able to absorb the energy of an incoming stone hitting it, and the glass may break. Therefore, the Young's modulus is 80 GPa or less, more preferably 78 GPa or less, and even more preferably 75 GPa or less. That is, the Young's modulus is preferably 65 GPa or more and 80 GPa or less. (T 11 )

[0092] In the glass according to the present embodiment, a temperature T 11 , where the glass viscosity is 10 11 [dPa s], preferably 640 °C or lower. If T 11 640 °C or lower, bending can be performed at a low temperature.

[0093] Examples of a method of setting T 11 to 640 °C or lower include a method of increasing the contents of B2O3, R2O, and RO and decreasing the content of Al2O3 in components of the glass, and a method of introducing Li2O from R2O. In the glass according to the present embodiment, T 11 more preferably 620 °C or lower, even more preferably 615 °C or lower, even more preferably 610 °C or lower, particularly preferably 605 °C or lower and especially 600 °C or lower.

[0094] In addition, T 11 With regard to the firing temperature of a black ceramic to be printed on a windshield, preferably 560 °C or higher, more preferably 570 °C or higher, even more preferably 575 °C or higher, and particularly preferably 580 °C or higher. That is, T 11 is preferably 560 °C or higher and 640 °C or lower. (T 12 )

[0095] In the glass according to the present embodiment, a temperature T 12 , where the glass viscosity is 10 12 [dPa s], preferably 600 °C or lower. If T 12 600 °C or lower, bending forming can be performed at a low temperature.

[0096] Examples of a method for setting T 12 to 600 °C or lower include a method of increasing the contents of B2O3, R2O, and RO and decreasing the content of Al2O3 in components of the glass, and a method of introducing Li2O from R2O. In the glass according to the present embodiment, T 12 more preferably 595 °C or lower, even more preferably 590 °C or lower, even more preferably 585 °C or lower, particularly preferably 580 °C or lower and especially 575 °C or lower.

[0097] In addition, T 12 With regard to the firing temperature of the black ceramic to be printed on a windshield, preferably 540 °C or higher, more preferably 545 °C or higher, even more preferably 550 °C or higher, particularly preferably 555 °C or higher, and especially 560 °C or higher. That is, T 12 is preferably 540 °C or higher and 600 °C or lower. (Average linear expansion coefficient)

[0098] The average linear expansion coefficient of the glass according to the present embodiment at 50 °C to 350 °C is preferably 40 × 10 -7 / °C or more. When the average linear expansion coefficient of the glass according to the present embodiment is 40 × 10 -7 / °C or more, air-cooling hardening treatment is simple, the difference in the linear expansion coefficient relative to the black ceramic is small, and cracking or breakage of the black ceramic can be prevented. To adjust the average linear expansion coefficient within the above range, a method of increasing the contents of B2O3, R2O, and RO and decreasing the content of Al2O3 in glass components can be used.

[0099] The average linear expansion coefficient of the glass according to the present embodiment at 50°C to 350°C is more preferably 45 × 10 -7 / °C or more, more preferably 47 × 10 -7 / °C or more, particularly preferably 50 × 10 -7 / °C or more and in particular 52 × 10 -7 / °C or more.

[0100] On the other hand, if the average linear expansion coefficient of the glass according to the present embodiment is too large, thermal stress is likely to occur due to a temperature distribution of the glass in a molding step and a slow cooling step for the glass or a molding step for a windshield, and thermal cracking of the glass may occur. Moreover, if the average linear expansion coefficient of the glass according to the present embodiment is too large, in the case where the glass is used as a vehicle window pane or a window pane for construction purposes, there is a risk of cracking due to thermal shock. The average linear expansion coefficient of the glass according to the present embodiment at 50°C to 350°C may be 70 × 10 -7 / °C or less and is preferably 65 × 10 -7 / °C or less, more preferably 63 × 10 -7 / °C or less, and more preferably 60 × 10 -7 / °C or less. That is, the average linear expansion coefficient at 50 °C to 350 °C is preferably 40 × 10 -7 / °C or more and 70 × 10 -7 / °C or less. (Relative density)

[0101] The glass according to the present embodiment preferably has a relative density of 2.40 or less.

[0102] A soda-lime-based glass widely used as a vehicle windowpane or a windowpane for construction has a specific gravity of about 2.51. However, the glass according to the present embodiment is an alkali borosilicate glass with a specific gravity lower than that of the soda-lime-based glass, and therefore is lightweight and can be used more conveniently as a vehicle windowpane or a windowpane for construction in view of fuel consumption and energy consumption. The specific gravity of the glass according to the present embodiment is more preferably 2.38 or less, even more preferably 2.36 or less, and particularly preferably 2.34 or less. Furthermore, in view of improving soundproofing properties in the vehicle, the specific gravity of the glass according to the present embodiment is preferably 2.25 or more, and more preferably 2.27 or more. That is,, the relative density of the glass is preferably 2.25 or more and 2.40 or less.

[0103] The glass according to the present embodiment preferably has a T 2,5 of 1600 °C or lower. In the glass according to the present embodiment, T4 is preferably 1200 °C or lower and T4-T L is preferably -50 °C or more. It should be noted that in the present description T 2,5 represents a temperature at which the glass viscosity is 10 2,5 dPa · s, T4 represents a temperature at which the glass viscosity 10 4 dPa · s and T L represents a liquid phase temperature of the glass.

[0104] If T 2,5 or T4 of the glass according to the present embodiment is higher than a predetermined temperature thereof, it is difficult to produce a large glass by a float method, a rolling method, a drawing method, or the like. In the glass according to the present embodiment, T 2,5 more preferably 1550°C or lower, even more preferably 1500°C or lower, and particularly preferably 1480°C or lower. In the glass according to the present embodiment, T4 is more preferably 1180°C or lower, even more preferably 1150°C or lower, and particularly preferably 1125°C or lower.

[0105] The lower limit of each of the T 2,5 and the T4 of the glass according to the present embodiment is not particularly limited, and in order to maintain weather resistance and stain resistance, T 2,5 typically 1300 °C or higher and T4 is typically 1000 °C or higher. T 2,5 of the glass according to the present embodiment is preferably 1350 °C or higher, and more preferably 1380 °C or higher. T4 of the glass according to the present embodiment is preferably 1020 °C or higher, and more preferably 1050 °C or higher. That is, T 2,5 is preferably 1300 °C or higher and 1600 °C or lower and T4 is preferably 1000 °C or higher and 1200 °C or lower.

[0106] Furthermore, T4-T L The temperature difference of the glass according to the present embodiment is preferably -50°C or more to enable production by a float process. When the difference is -50°C or more, the occurrence of devitrification in the glass during glass forming can be prevented, the mechanical properties of the glass are improved, and further, a glass with improved transparency and excellent quality can be obtained. T4-T L of the glass according to the present embodiment is more preferably -25 °C or more, even more preferably 0 °C or more, and particularly preferably 20 °C or more.

[0107] Furthermore, the glass according to the present embodiment preferably has a T g of 460 °C or higher and 580 °C or lower. It should be noted that in this specification, T g represents a glass transition point. If T g is within this specified temperature range, the glass can be bent within general manufacturing conditions. If T g of the glass according to the present embodiment is lower than 460°C, there is no problem with formability, but the alkali content or alkaline earth content is too high, and problems such as excessive thermal expansion of the glass and a decrease in weather resistance and stain resistance, etc., are likely to occur. In addition, if the T g of the glass according to the present embodiment is lower than 460 °C, the glass may devitrify and may not be formed in a forming temperature range.

[0108] The T g of the glass according to the present embodiment is more preferably 480 °C or higher, even more preferably 490 °C or higher, and particularly preferably 500 °C or higher. On the other hand, the T g of the glass according to the present embodiment, in view of facilitating manufacture during glass bending, more preferably 570 °C or lower, even more preferably 565 °C or lower, and particularly preferably 560 °C or lower.

[0109] In the alkali borosilicate glass according to the present embodiment, the presence of moisture in the glass has an effect of reducing the T 11 and the T 12 which makes bending and forming the glass easier. Therefore, the alkali borosilicate glass according to the present embodiment preferably contains a certain amount of moisture. The moisture in the glass can generally be expressed by a value called the β-OH value, and the β-OH value is preferably 0.050 mm -1 or more, more preferably 0.10 mm -1 or more, more preferably 0.15 mm -1 or more and particularly preferably 0.20 mm -1 or more. β-OH is obtained by the following equation based on the transmittance of the glass measured using an FT-IR (Fourier transform infrared spectrophotometer). β−OH=(1 / X)log10(TA / TB)[mm−1] X: Sample thickness [mm] T A : Transmittance [%] at a reference wavenumber of 4000 cm -1 T B : Minimum transmittance [%] near a hydroxy group absorption wavenumber of 3600 cm -1

[0110] On the other hand, if the amount of moisture in the glass is too large, the network structure of the glass may be affected, resulting in a deterioration in resistance to flying stones. Therefore, the β-OH value of the alkali borosilicate glass according to the present embodiment is preferably 0.70 mm. -1 or less, more preferably 0.60 mm -1 or less, more preferably 0.50 mm -1 or less and particularly preferably 0.40 mm -1 or less. That is, the β-OH value is preferably 0.050 mm -1 or more and 0.70 mm -1 or less.

[0111] When the thickness of the glass according to the present embodiment is converted to 2.00 mm, L* specified in JIS Z 8781-4:2003 using a D65 light source is preferably 84.0 or more, more preferably 86.0 or more, even more preferably 88.0 or more, and even more preferably 90.0 or more. The upper limit of L* is not specifically limited and is 100.0 or less. That is, L* is preferably 84.0 or more and 100.0 or less.

[0112] When the thickness of the glass according to the present embodiment is converted to 2.00 mm, a* specified in JIS Z 8781-4:2003 using a D65 light source is preferably -5.0 or more, more preferably -3.0 or more, and even more preferably -2.0 or more. Furthermore, a* is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.0 or less. That is, a* is preferably -5.0 or more and 2.0 or less.

[0113] Furthermore, when the thickness is converted to 2.00 mm, b* specified in JIS Z 8781-4:2003 using a D65 light source is preferably -5.0 or more, more preferably -3.0 or more, and even more preferably -1.0 or more. Furthermore, b* is preferably 5.0 or less, more preferably 3.0 or less, even more preferably 2.0 or less, and particularly preferably 1.5 or less. That is, b* is preferably -5.0 or more and 5.0 or less.

[0114] When L*, a* and b* are within the above ranges, the glass according to the present embodiment has excellent designability and can be suitably used as a vehicle window glass or a window glass for construction purposes.

[0115] Furthermore, in the glass according to the present embodiment, c*, which is given by c* = {(a*) 2 + (b*) 2 } 1 / 2 is set, preferably 3.5 or less, more preferably 3.0 or less, even more preferably 2.5 or less, and particularly preferably 2.0 or less. The smaller c* is, the lower the saturation and the darker the gray color of the glass appears. Moreover, the lower limit of c* is not specifically limited and is generally 0.0 or more. That is, c* is preferably 0.0 or more and 3.5 or less.

[0116] The glass according to the present embodiment is preferably, for example, a float glass produced by a known float method. In the float method, a molten glass base material is floated on a molten metal, such as tin, and with a precise temperature control process, a glass with a uniform thickness and plate width can be produced, and a glass with a large area can be obtained.

[0117] Alternatively, a glass formed by a known rolling or drawing process can be used, or a glass with a polished surface and a uniform sheet thickness can be used. The drawing process is roughly classified into a slot drawing process and an overflow drawing process (fusion process). Both processes involve continuously pouring molten glass downward from a mold body to form a glass ribbon in a ribbon-plate shape.

[0118] The shape of the glass according to the present embodiment is not particularly limited, and a main surface thereof has an area of ​​preferably 250000 mm 2 or more, more preferably 450000 mm 2 or more and even more preferably 900000 mm 2 or more. If the area of ​​the glass is within the above range, the glass can be suitably used for various types of vehicles. In addition, if the area of ​​the glass is too large, difficulties in bending and forming increase, such as difficulty in handling the glass, uneven temperature distribution during heating, and deterioration of dimensional accuracy after bending and forming. Therefore, the area of ​​the main surface of the glass according to the present embodiment is preferably 4000000 mm 2 or less, more preferably 3500000 mm 2 or less and more preferably 3000000 mm 2 or less. That is, the area of ​​the main surface of the glass according to the present embodiment is preferably 250000 mm 2 or more and 4000000 mm 2 or less.

[0119] Furthermore, the glass according to the present embodiment preferably has a thickness of 0.50 mm or more to improve rigidity and improve strength when the glass comes into contact with flying stones, vehicle keys, or the like. The thickness of the glass is more preferably 1.00 mm or more, even more preferably 1.50 mm or more, particularly preferably 2.00 mm or more, and particularly preferably 2.50 mm or more. Moreover, in view of an increase in fuel consumption and energy consumption due to an increase in glass weight, the thickness of the glass according to the present embodiment is preferably 4.00 mm or less, more preferably 3.80 mm or less, and even more preferably 3.50 mm or less. That is, the thickness of the glass is preferably 0.50 mm or more and 4.00 mm or less.

[0120] The glass according to the present embodiment may be a glass subjected to a toughening treatment, such as air-cooling or chemical toughening. With the above-mentioned treatment, the strength of the glass can be improved.

[0121] Air-cooled tempering is a process that forms a compressive stress layer on the glass surface through thermal tempering. Specifically, a uniformly heated glass plate is rapidly cooled from a temperature near its softening point, and compressive stress is generated on the glass surface due to a temperature difference between the glass surface and the interior of the glass. The compressive stress is generated uniformly across the entire glass surface, and a compressive stress layer of uniform depth is formed across the entire glass surface. Thermal tempering is more suitable for tempering thick glass plates than chemical tempering.

[0122] Furthermore, chemical strengthening is a treatment in which alkali metal ions with a small ionic radius (typically Li ions or Na ions) on the glass surface are replaced by alkali metal ions with a large ionic radius (typically Na ions or K ions) through ion exchange at a temperature identical to or lower than the glass transition point, thereby forming a compressive stress layer on the glass surface. The chemical strengthening treatment can be performed using a known method, such as an ion exchange process.In the ion exchange process, a glass plate is immersed in a treatment liquid (e.g., molten potassium nitrate salt), and ions with a small ionic radius (e.g., Na ions) contained in the glass are exchanged for ions with a large ionic radius (e.g., K ions), thereby forming a compressive stress on the surface of the glass.

[0123] Each of a magnitude of compressive stress on the surface of the glass plate (hereinafter also referred to as surface compressive stress CS) and a depth DOL of the compressive stress layer formed on the surface of the glass plate can be adjusted based on a glass composition, a time of chemical strengthening treatment, and a temperature of chemical strengthening treatment. [Curved glass]

[0124] A bent glass according to the present embodiment comprises the above-mentioned alkali borosilicate glass. That is, it is formed by bending the above-mentioned alkali borosilicate glass. The bent glass according to the present embodiment may be a bent glass formed by forming a flat, plate-shaped alkali borosilicate glass into a curved shape by gravity molding, compression molding, or the like.

[0125] The bent glass according to the present embodiment is a glass curved with a predetermined curvature, which may be a single-bent glass curved in only one direction, either an up-down direction or a right-left direction, or a multi-bent glass curved in both the up-down direction and the right-left direction.

[0126] The bent glass according to the present embodiment preferably has a minimum radius of curvature of 500 mm or more and 100,000 mm or less. Regarding the radius of curvature of the bent glass, the shape of the sample is calculated by shape simulation using a laser displacement meter (Dyvoce, manufactured by Kohzu Precision Co., Ltd.) based on the amount of curvature inherent in the sample determined by self-weight deflection correction in a double-sided differential mode, and the radius of curvature is determined based on the shape obtained by the simulation. [Method for producing a curved glass]

[0127] In a method for producing a bent glass according to the present embodiment, a bent glass is obtained by heating and bending the above-mentioned alkali borosilicate glass.

[0128] Examples of a forming method for the bent glass include a method of bending and forming a heated glass in a state where it is placed in a mold and pressed from above using a press.

[0129] Further examples include a method of placing a flat, plate-shaped glass on a mold having a bending and forming surface corresponding to a desired curved surface, placing the mold in this state into a heating furnace, and heating the glass in the heating furnace to a temperature near the softening point of the glass. According to this molding method, a glass having a desired curved surface is produced because the glass is curved along the bending and forming surface of the mold due to its own weight along with softening.

[0130] In the present embodiment, the above-mentioned bending and forming using a press is preferred in view of improving productivity and improving surface accuracy after forming. The above-mentioned bending and forming method using a press is not particularly limited, and, for example, the method described in WO 2016 / 093031 can be used appropriately. The above-mentioned bending and forming method using a press is exemplified below.

[0131] First, the alkali borosilicate glass according to the present embodiment is transported to a pressing area using a transport conveyor. Next, the alkali borosilicate glass is softened in the pressing area by heating it to a temperature at which it can be bent and shaped.

[0132] The temperature at which the alkali borosilicate glass can be bent and formed can be determined, for example, by the temperature T 11 , where the glass viscosity is 10 11 [dPa s], be identical to or higher than this. It should be noted that heating using a heater or the like in the heating furnace may be performed in the process of transporting the alkali borosilicate glass to the pressing area using the transport conveyor or the like.

[0133] In addition, a bending and forming time can be reduced under the condition that the heating temperature (≥ T 11 ) is maintained, for example, set to 1 second or longer.

[0134] A lower press die (negative die) and an upper press die (positive die) are arranged at predetermined positions in the pressing area, and an upper surface shape of the negative die and a lower surface shape of the positive die correspond to the curved shape of the alkali borosilicate glass to be subjected to bending and forming in a conveying direction and an orthogonal direction. The negative die can be moved up and down between a standby position below the conveying conveyor and a pressing position above the conveying conveyor. After the glass is transferred from the conveying conveyor, it is moved from a predetermined raised position to the pressing position above the conveying conveyor with the glass placed thereon, thereby subjecting the alkali borosilicate glass to compression molding.

[0135] Next, the molded alkali borosilicate glass is transported to a cooling area using a transport device or the like. In the cooling area, the alkali borosilicate glass is cooled by blowing cooling air onto the alkali borosilicate glass.

[0136] Through the above steps, a bent glass is formed. It should be noted that although the bending and forming of the alkali borosilicate glass according to the present embodiment has been described above, the bending and forming can also be performed in the state of a laminated glass, which will be described later. [Laminated glass]

[0137] A laminated glass according to the present embodiment comprises: a first glass plate; a second glass plate; and an intermediate layer disposed between the first glass plate and the second glass plate, wherein the first glass plate is the above alkali borosilicate glass or the above bent glass.

[0138] The Fig. Fig. 4 is a view showing an example of a laminated glass 10 according to the present embodiment. The laminated glass 10 includes a first glass plate 11, a second glass plate 12, and an intermediate layer 13 disposed between the first glass plate 11 and the second glass plate 12. It should be noted that the laminated glass 10 according to the present embodiment is not limited to any aspect in the Fig. 4 and may be modified without departing from the essence of the present invention. For example, the intermediate layer 13 may be formed as a layer as shown in Fig. 4, or it may be formed as two or more layers. Furthermore, the laminated glass 10 according to the present embodiment may include three or more glass plates, and in this case, an organic resin or the like may be interposed between adjacent glass plates. Hereinafter, the laminated glass 10 according to the present embodiment will be described as a structure in which only two glass plates, that is, the first glass plate 11 and the second glass plate 12, are included, and the intermediate layer 13 is interposed therebetween.

[0139] In the laminated glass according to the present embodiment, the second glass plate 12 is preferably the above alkali borosilicate glass or the above bent glass in view of bending formability. In the case where the first glass plate 11 and the second glass plate 12 are each the above alkali borosilicate glass or the above bent glass, the first glass plate 11 and the second glass plate 12 may be glass plates with the same composition or may be glass plates with different compositions.

[0140] In the case where the second glass plate 12 is not the above-mentioned alkali borosilicate glass, the type of glass plate is not particularly limited, and a known glass plate used in the prior art for a vehicle window or the like can be used. Specific examples include alkali aluminosilicate glass, alkali aluminoborosilicate glass, and soda-lime glass. These glass plates may be colored to an extent that their transparency is not impaired, or they may be uncolored.

[0141] In the laminated glass according to the present embodiment, the second glass plate 12 may be an alkali aluminosilicate glass containing 1.0% or more of Al2O3, or may be an alkali aluminoborosilicate glass containing 1.0% or more of Al2O3 and 1.0% or more of B2O3. By using the above-mentioned alkali aluminosilicate glass or alkali aluminoborosilicate glass as the second glass plate 12, chemical strengthening described later can be performed and the strength can be improved.

[0142] In the alkali aluminosilicate glass and the alkali aluminoborosilicate glass mentioned above, the content of Al2O3 is more preferably 5.0% or more, even more preferably 8.0% or more, and particularly preferably 10% or more, from the viewpoint of improving weather resistance, stain resistance, and chemical strengthening properties. Furthermore, the content of Al2O3 is preferably 18% or less, more preferably 15% or less, to reduce glass viscosity and simplify glass manufacturing.

[0143] In the alkali aluminosilicate glass and the alkali aluminoborosilicate glass mentioned above, the content of R2O is preferably 10% or more, more preferably 12% or more, and even more preferably 13% or more, from the viewpoint of chemical strengthening. Furthermore, the content of R2O is preferably 22% or less, more preferably 20% or less, and even more preferably 18% or less, from the viewpoint of improving stain resistance.

[0144] In the above-mentioned alkali aluminoborosilicate glass, the content of B2O3 is preferably 2.0% or more, more preferably 3.0% or more, and even more preferably 4.0% or more to improve strength when the glass comes into contact with flying stones, vehicle keys, or the like. Furthermore, in the alkali aluminoborosilicate glass, the content of B2O3 is preferably 9.0% or less, more preferably 8.0% or less, and even more preferably 7.0% or less to improve chemical durability and weather resistance.

[0145] Specific examples of the above alkali aluminosilicate glass include a glass with the following composition. Each component is expressed as oxides in mol%. 61% ≤ SiO2 ≤ 77% 1.0% ≤ Al2O3 ≤ 20% 0.0% ≤ MgO ≤ 15% 0.0% ≤ CaO ≤ 10% 0.0% ≤ SrO ≤ 1.0% 0.0% ≤ BaO ≤ 1.0% 0.0% ≤ Li2O ≤ 15% 2.0% ≤ Na2O ≤ 15% 0.0% ≤ K2O ≤ 6.0% 0.0% ≤ ZrO2 ≤ 4.0% 0.0% ≤ TiO2 ≤ 1.0% 0.0% ≤ Y2O3 ≤ 2.0% 10% ≤ R2O ≤ 25% 0.0% ≤ RO ≤ 20% (R2O represents the total content of Li2O, Na2O, and K2O, and RO represents the total content of MgO, CaO, SrO, and BaO.)

[0146] Specific examples of the above-mentioned alkali aluminoborosilicate glass include a glass with the following composition. Each component is expressed as oxides in mol%. 61% ≤ SiO2 ≤ 77% 1.0% ≤ Al2O3 ≤ 20% 1.0% ≤ B2O3 ≤ 10% 0.0% ≤ MgO ≤ 15% 0.0% ≤ CaO ≤ 10% 0.0% ≤ SrO ≤ 1.0% 0.0% ≤ BaO ≤ 1.0% 0.0% ≤ Li2O ≤ 15% 2.0% ≤ Na2O ≤ 15% 0.0% ≤ K2O ≤ 6.0% 0.0% ≤ ZrO2 ≤ 4.0% 0.0% ≤ TiO2 ≤ 1.0% 0.0% ≤ Y2O3 ≤ 2.0% 10% ≤ R2O ≤ 25% 0.0% ≤ RO ≤ 20% (R2O represents the total content of Li2O, Na2O, and K2O, and RO represents the total content of MgO, CaO, SrO, and BaO.)

[0147] Furthermore, in the laminated glass according to the present embodiment, the second glass plate 12 may be a soda-lime glass. The soda-lime glass may be a soda-lime glass containing less than 1.0% Al2O3. Specific examples thereof include a glass having the following composition. Each component is expressed in mol% as oxides. 60% ≤ SiO2 ≤ 75% 0.0% ≤ Al2O3 < 1.0% 2.0% ≤ MgO ≤ 11% 2.0% ≤ CaO ≤ 10% 0.0% ≤ SrO ≤ 3.0% 0.0% ≤ BaO ≤ 3.0% 10% ≤ Na2O ≤ 18% 0.0% ≤ K2O ≤ 8.0% 0.0% ≤ ZrO2 ≤ 4.0% 0.0010% ≤ Fe2O3 ≤ 5.0%

[0148] Furthermore, in the laminated glass according to the present embodiment, the second glass plate 12 may be a soda-lime glass having the following composition. Each component is expressed in mol% as oxides. 60% ≤ SiO2 ≤ 75% 0.0% ≤ Al2O3 ≤ 3.5% 2.0% ≤ MgO ≤ 11% 2.0% ≤ CaO ≤ 10% 0.0% ≤ SrO ≤ 3.0% 0.0% ≤ BaO ≤ 3.0% 10% ≤ Na2O ≤ 18% 0.0% ≤ K2O ≤ 8.0% 0.0% ≤ ZrO2 ≤ 4.0% 0.0010% ≤ Fe2O3 ≤ 5.0%

[0149] The first glass plate 11 and the second glass plate 12 preferably have the same thickness. When the first glass plate 11 and the second glass plate 12 have the same thickness, dimensional accuracy during bending and forming is improved. In the present embodiment, it is more preferable that the thickness of the first glass plate 11 be greater than the thickness of the second glass plate 12. It should be noted that the thickness of the first glass plate 11 and the thickness of the second glass plate 12 may differ from each other.

[0150] The thickness of the first glass plate 11 is preferably 2.00 mm or more. When the thickness of the first glass plate 11 is 2.00 mm or more, the soundproofing properties and the resistance to flying stones are improved. The thickness of the first glass plate 11 is more preferably 2.25 mm or more, even more preferably 2.50 mm or more, particularly preferably 2.75 mm or more, and particularly preferably 3.00 mm or more. Furthermore, the thickness of the first glass plate 11 is preferably 5.00 mm or less. When the thickness of the first glass plate 11 is 5.00 mm or less, the weight of the laminated glass 10 is not excessive, which is preferable in view of reducing energy consumption and fuel consumption in the case of use for a vehicle.The thickness of the first glass plate 11 is more preferably 4.75 mm or less, even more preferably 4.50 mm or less, particularly preferably 4.25 mm or less, and most preferably 4.00 mm or less. That is, the thickness of the first glass plate 11 is preferably 2.00 mm or more and 5.00 mm or less.

[0151] The thickness of the second glass plate 12 is preferably less than 2.00 mm. When the thickness of the second glass plate 12 is less than 2.00 mm, even if the thickness of the first glass plate 11 is increased, the weight of the laminated glass 10 does not become excessive, which is preferable from the viewpoint of reducing energy consumption and fuel consumption in the case of use for a vehicle. The thickness of the second glass plate 12 is more preferably 1.80 mm or less, even more preferably 1.50 mm or less, particularly preferably 1.30 mm or less, and particularly preferably 1.10 mm or less. Furthermore, the thickness of the second glass plate 12 is preferably 0.500 mm or more. When the thickness of the second glass plate 12 is 0.500 mm or more, the strength is improved when vehicle keys or the like come into contact with the glass inside the vehicle.The thickness of the second glass plate 12 is more preferably 0.700 mm or more, even more preferably 0.800 mm or more, and particularly preferably 0.900 mm or more. That is, the thickness of the second glass plate 12 is preferably 0.500 mm or more and less than 2.00 mm.

[0152] In the laminated glass 10 according to the present embodiment, the total thickness of the first glass plate 11, the second glass plate 12, and the intermediate layer 13 is preferably 2.80 mm or more. When the total thickness is 2.80 mm or more, sufficient strength is obtained. The total thickness is more preferably 3.00 mm or more, even more preferably 3.50 mm or more, even more preferably 4.00 mm or more, particularly preferably 4.50 mm or more, and particularly preferably 4.70 mm or more. Moreover, the total thickness may be 6.00 mm or less, and from the viewpoint of weight reduction, it is preferably 5.80 mm or less, more preferably 5.60 mm or less, and even more preferably 5.40 mm or less. That is, the total thickness is preferably 2.80 mm or more and 6.00 mm or less.

[0153] It should be noted that in the laminated glass 10 according to the present embodiment, the thicknesses of the first glass plate 11 and the second glass plate 12 may be constant over the entire surface or may be changed for each portion as needed, such as by forming 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.

[0154] One of the first glass plate 11 and the second glass plate 12 may be a chemically strengthened glass that has undergone glass strengthening to improve strength. The method of the chemical strengthening treatment is identical to that of the chemical strengthening treatment for the aforementioned alkali borosilicate glass. Examples of the chemically strengthened glass include the aforementioned alkali aluminosilicate glass and the aforementioned alkali aluminoborosilicate glass that have undergone chemical strengthening.

[0155] The shape of the first glass plate 11 and the second glass plate 12 may be a flat plate shape or may be a curved shape with a curvature on the entire surface or part thereof. In the case where the first glass plate 11 and the second glass plate 12 are curved, the first glass plate 11 and the second glass plate 12 may have a single-curved shape curved in only one direction of either the up-down direction or the right-left direction, or may have a multi-curved shape curved in both the up-down direction and the right-left direction. In the case where the first glass plate 11 and the second glass plate 12 have a multi-curved shape, their radius of curvature in the up-down direction and the right-left direction may be the same or different.In the case where the first glass panel 11 and the second glass panel 12 are curved, the radius of curvature in the up-down direction and / or the right-left direction is preferably 1000 mm or more. The shape of a main surface of the first glass panel 11 and the second glass panel 12 is a shape that fits into a window opening of a vehicle to which the first glass panel 11 and the second glass panel 12 are to be mounted.

[0156] The intermediate layer 13 according to the present embodiment is arranged between the first glass plate 11 and the second glass plate 12. Since the laminated glass 10 according to the present embodiment includes the intermediate layer 13, the first glass plate 11 and the second glass plate 12 adhere firmly to each other, and an impact force when scattered pieces collide with the glass plate can be reduced.

[0157] As the intermediate layer 13, various organic resins generally used for a laminated glass used in the prior art as a laminated glass for a vehicle can be used.As the organic resin, for example, a polyethylene (PE), an ethylene-vinyl acetate copolymer (EVA), a polypropylene (PP), a polystyrene (PS), a methacrylate resin (PMA), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), cellulose acetate (CA), a diallyl phthalate resin (DAP), a urea resin (UP), a melamine resin (MF), an unsaturated polyester (UP), polyvinyl butyral (PVB), polyvinyl formal (PVF), polyvinyl alcohol (PVAL), a vinyl acetate resin (PVAc), an ionomer (IO), polymethylpentene (TPX), vinylidene chloride (PVDC), polysulfone (PSF), polyvinylidene difluoride (PVDF), a methacrylate-styrene copolymer resin (MS), a polyarylate (PAR), polyarylsulfone (PASF), a polybutadiene (BR), polyethersulfone (PESF) or polyetheretherketone (PEEK) can be used. Of these, EVA and PVB are suitable in terms of transparency and adhesion, and in particular, PVB is more preferred because it can provide sound-shielding properties.

[0158] The thickness of the intermediate layer 13 is preferably 0.300 mm or more, more preferably 0.500 mm or more, and even more preferably 0.700 mm or more, from the viewpoint of reducing impact force and sound-shielding properties. Furthermore, from the viewpoint of preventing a reduction in visible light transmittance, the thickness of the intermediate layer 13 is preferably 1.00 mm or less, more preferably 0.900 mm or less, and even more preferably 0.800 mm or less. Furthermore, the thickness of the intermediate layer 13 is preferably in a range of 0.300 mm to 1.00 mm, and more preferably in a range of 0.700 mm to 0.800 mm.

[0159] The thickness of the intermediate layer 13 may be constant over the entire surface or may be changed for each section if necessary.

[0160] It should be noted that if the difference in the linear expansion coefficient between the intermediate layer 13 and the first glass plate 11 or the second glass plate 12 is large, in the case where the laminated glass 10 is produced by a heating step described later, the laminated glass 10 may crack or warp, resulting in poor appearance. Therefore, the difference in the linear expansion coefficient between the intermediate layer 13 and the first glass plate 11 or the second glass plate 12 is preferably as small as possible. The difference in the linear expansion coefficient between the intermediate layer 13 and the first glass plate 11 or the second glass plate 12 can be represented by a difference between the average linear expansion coefficients in a given temperature range.

[0161] In particular, a resin forming the intermediate layer 13 has a low glass transition point, and thus, a predetermined difference in the average linear expansion coefficient can be set within a temperature range identical to or lower than the glass transition point of the resin material. Note that a difference in the linear expansion coefficient between the resin material and the first glass plate 11 or the second glass plate 12 can be set to a predetermined temperature identical to or lower than the glass transition point of the resin material.

[0162] As the intermediate layer 13, an adhesive layer containing an adhesive can be used, and the adhesive is not particularly limited, and for example, an acrylic adhesive or a silicone adhesive can be used.

[0163] In the case where the intermediate layer 13 is an adhesive layer, it is not necessary to perform the heating step in the process of bonding the first glass plate 11 and the second glass plate 12, and hence the cracks or warpage mentioned above are less likely to occur. [More layers]

[0164] The laminated glass 10 according to the present embodiment may include layers other than those of the first glass plate 11, the second glass plate 12, and the intermediate layer 13 (hereinafter also referred to as "other layers") within a range that does not impair the effects of the present invention. For example, a coating layer providing a water-repellent function, a hydrophilic function, an anti-fogging function, or the like, or an infrared reflection film may be provided.

[0165] Positions where the further layers are provided are not particularly limited, and the further layers may be provided on a surface of the laminated glass 10 or may be disposed between the first glass plate 11, the second glass plate 12, or the intermediate layer 13. Moreover, the laminated glass 10 according to the present embodiment may include a black ceramic layer or the like provided in a band shape on part or all of a peripheral edge portion for the purpose of concealing a portion for attachment to a frame body or the like, a wiring conductor, or the like.

[0166] A method for manufacturing the laminated glass 10 according to the present embodiment may be identical to the method for a known laminated glass in the prior art. For example, by laminating the first glass plate 11, the intermediate layer 13, and the second glass plate 12 in this order, and performing heating and pressing, the laminated glass 10 having a structure in which the first glass plate 11 and the second glass plate 12 are bonded via the intermediate layer 13 is obtained.

[0167] In the method for manufacturing the laminated glass 10 according to the present embodiment, for example, after a step of heating and forming each of the first glass plate 11 and the second glass plate 12, a step of inserting the intermediate layer 13 between the first glass plate 11 and the second glass plate 12 and performing heating and pressing may be performed. Through such steps, the laminated glass 10 having the structure in which the first glass plate 11 and the second glass plate 12 are bonded via the intermediate layer 13 can be obtained.

[0168] In the laminated glass 10 according to the present embodiment, the visible light transmittance Tv specified in ISO-9050:2003 using a D65 light source is preferably 70% or more. Tv is more preferably 71% or more, and even more preferably 72% or more. Moreover, Tv is, for example, 90% or less. That is, Tv is, for example, 70% or more and 90% or less.

[0169] In the laminated glass 10 according to the present embodiment, the total sunlight transmittance Tts, as specified in ISO-13837:2008, Guideline A, measured at a wind speed of 4 m / s, is preferably 70% or less. When the total sunlight transmittance Tts of the laminated glass 10 according to the present embodiment is 70% or less, sufficient heat shielding properties are obtained. Tts is more preferably 68% or less, and even more preferably 66% or less. Moreover, Tts is, for example, 55% or more. That is, Tts is, for example, 55% or more and 70% or less.

[0170] In the laminated glass 10 according to the present embodiment, the chromaticity value a* specified in JIS Z 8781-4:2013 using a D65 light source is preferably -5.0 or more, more preferably -4.0 or more, even more preferably -3.0 or more, and particularly preferably -2.0 or more. Furthermore, a* is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0 or less. That is, a* is preferably -5.0 or more and 2.0 or less.

[0171] Furthermore, in the laminated glass 10 according to the present embodiment, the chromaticity value b* specified in JIS Z 8781-4:2013 using a D65 light source is preferably -5.0 or more, more preferably -3.0 or more, and even more preferably -1.0 or more. Furthermore, b* is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.0 or less, and particularly preferably 2.5 or less. That is, b* is preferably -5.0 or more and 5.0 or less.

[0172] When a* and b* are within the above ranges, the glass panel according to the present embodiment has excellent designability and is suitable for use as a window pane for construction and a vehicle window pane.

[0173] Further, in the laminated glass 10 according to the present embodiment, c*, which is given by c* = {(a*) 2 +(b*) 2 } 1 / 2 is preferably 4.0 or less, more preferably 3.5 or less, even more preferably 3.0 or less, and particularly preferably 2.5 or less. Moreover, the lower limit of c* is not specifically limited and is generally 0.0 or more. That is, c* is preferably 0.0 or more and 4.0 or less.

[0174] When a*, b* and c* are within the above ranges, the glass panel according to the present embodiment has excellent designability and is suitable for use as a window pane for construction and a vehicle window pane. [Construction window pane and vehicle window pane]

[0175] A window pane for construction and a vehicle window pane according to the present embodiment comprise the above-mentioned alkali borosilicate glass. The window pane for construction and the vehicle window pane according to the present embodiment may be made of the above-mentioned laminated glass.

[0176] Hereinafter, an example in which the laminated glass 10 according to the present embodiment is used as the vehicle window glass will be described with reference to the drawings.

[0177] The Fig. 5 is a schematic view showing a state in which the laminated glass 10 according to the present embodiment is mounted on an opening 110 formed at a front part of a motor vehicle 100, so that it is used as a motor vehicle window glass. In the laminated glass 10 used as a motor vehicle window glass, a case (box) 120 in which an information device or the like for ensuring driving safety of the vehicle is housed may be attached to a surface on an interior side of the vehicle.

[0178] The information device accommodated in the housing is a device that uses a camera, radar, or the like to prevent a rear-end collision or a collision with a preceding vehicle, a pedestrian, an obstacle, or the like in front of the vehicle, or to notify a driver of a hazard. For example, the information device is an information receiving device and / or an information transmitting device, includes a millimeter-wave radar, a stereo camera, an infrared laser, or the like, and transmits and receives a signal. The "signal" is an electromagnetic wave including a millimeter wave, visible light, or infrared light.

[0179] The Fig. Figure 6 is an enlarged view of a section S in the Fig. 5 is a perspective view showing a portion where the housing 120 is attached to the laminated glass 10 according to the present embodiment. A millimeter-wave radar 201 and a stereo camera 202 as an information device are housed in the housing 120. The housing 120, in which the information device is housed, is generally attached to a vehicle exterior with respect to a rearview mirror 150 and a vehicle interior with respect to the laminated glass 10, or may be attached to another portion.

[0180] The Fig. 7 is a cross-sectional view showing a YY in the Fig. 6 in a direction orthogonal to a horizontal line. The first glass plate 11 of the laminated glass 10 is preferably arranged on the vehicle exterior. With the above structure, a windshield can be provided that has high resistance to flying stones and high rigidity, is lightweight, and has excellent gray color designability. Examples

[0181] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. <Herstellung von Glasplatten im Beispiel 1 bis Beispiel 35>

[0182] Raw materials were placed in a platinum crucible to obtain each glass composition (unit: mol%) shown in Table 1 and Table 2, and melted at a temperature of 1600°C to 1650°C for 3 hours to obtain each molten glass. The molten glass was poured onto a carbon plate and slowly cooled. Both surfaces of the resulting plate-shaped glass were polished to obtain a glass plate with a thickness of 2.00 mm. Examples 1 to 10 are comparative examples, and Examples 11 to 35 are examples of the present invention.

[0183] According to Table 1 and Table 2, in addition to the composition, the proportion of three-coordinate boron (B 3 [%]), the proportion of four-coordinate boron (B 4 [%]), the content of the three-coordinate boron as B2O3 (B 3 as B2O3 [mol-%]) and the content of four-coordinate boron as B2O3 (B 4 as B2O3 [mol%]) introduced as starting materials, and Fe redox, visible light transmittance Tv, sunlight transmittance Te, ultraviolet transmittance Tuv, color value, dominant wavelength Dw, ​​excitation purity Pe, viscosity, relative density, Young's modulus, and average linear expansion coefficient were measured.

[0184] Methods for determining the numerical values ​​given in Table 1 and Table 2 are shown below. (1) Coordination number of boron: The coordination number ratio of boron atoms in the glass was analyzed using NMR. The NMR measurement conditions were as follows: Instrument: Nuclear Magnetic Resonance (ECZ700) manufactured by JEOL Ltd., resonance frequency: 156.38 MHz, rotation speed: 15 kHz, probe: 3.2 mm for solid, tilt angle: 90°, pulse repetition delay: 16 s. The measurement was performed using a single-pulse method, using adamantane as an external standard (28.46 ppm and 37.85 ppm of 13C). The measurement results were subjected to phase correction and baseline correction using NMR software Delta, manufactured by JEOL Ltd., then a fitting was performed using a Gaussian function to calculate the three-coordination and four-coordination fractions, and an average coordination number was determined. Phase correction and baseline correction were performed by subtracting the spectrum of an empty cell containing no sample in an appropriate manner. For peak fitting, the peak apex was adjusted to 20 ppm to 8 ppm for triple coordination and 5 ppm to -5 ppm for quadruple coordination, and a good fit was obtained by appropriately adjusting the peak width (so that the ratio between the coordination numbers was at most 1.5-fold or less). (2) Fe redox: Fe redox was determined using the following procedure. A crushed glass was decomposed with a mixed acid of hydrofluoric acid and hydrochloric acid at room temperature, then a certain amount of the decomposition solution was placed in a plastic container and a hydroxylammonium chloride solution was added to reduce Fe 3+ in the sample solution to Fe 2+ was added. Then, a 2,2'-dipyridyl solution and an ammonium acetate buffer solution were added to adjust the color of Fe 2+ A color developing solution was adjusted to a specific volume with ion-exchange water, and the absorbance at a wavelength of 522 nm was measured with an absorption spectrophotometer. Then, a concentration was calculated based on a calibration curve prepared using the standard solution to determine the amount of Fe. 2+ to determine. Since Fe 3+ in the sample solution to Fe 2+ is reduced, the amount of Fe 2+ for "[Fe 2+ ] + [Fe 3+ ]" in the sample. Next, a crushed glass was decomposed with a mixed acid of hydrofluoric acid and hydrochloric acid at room temperature, then a certain amount of the decomposition solution was placed in a plastic container, and a 2,2'-dipyridyl solution and an ammonium acetate buffer solution were quickly added to only change the color of Fe 2+ A color developing solution was adjusted to a specific volume with ion-exchange water, and the absorbance at a wavelength of 522 nm was measured with a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.). Then, a concentration was calculated based on a calibration curve prepared using the standard solution to determine the amount of Fe. 2+ to obtain. The amount of Fe 2+ stands for [Fe 2+ ] in the sample. Then Fe-redox was: [Fe 2+ ] / ([Fe 2+ ] + [Fe 3+ ]) based on the obtained [Fe 2+ ] and [Fe 2+ ] + [Fe 3+ ] certainly. (3) Visible light transmittance (Tv): The Tv, when the thickness of the glass plate was converted to 2.0 mm, was measured using a D65 light source according to a method specified in ISO 9050:2003. It should be noted that the Tv was measured using a LAMBDA 950 spectrophotometer manufactured by PerkinElmer. (4) Sunlight transmittance (Te): The solar transmittance Te is a solar transmittance calculated by measuring the transmittance using a spectrophotometer, i.e., a LAMBDA 950 spectrophotometer manufactured by Perkinelmer, according to the specifications in ISO-9050:2003. (5) Ultraviolet transmittance (Tuv): The TUV, when the thickness of the glass plate was converted to 2.0 mm, was measured using a method specified in ISO 9050:2003. It should be noted that the TUV was measured using a LAMBDA 950 spectrophotometer manufactured by PerkinElmer. (6) Colour value (L*, a*, b* and c*): The color values ​​L*, a*, and b*, specified in JIS Z 8781-4:2013, were measured using a D65 light source. The obtained values ​​of a* and b* were substituted into the following equation to determine c*. c*={(a*)2+(b*)2}1 / 2 (7) Predominant wavelength (Dw): The dominant wavelength Dw of transmitted light is a dominant wavelength of transmitted light calculated according to JIS Z 8701:1999. (8) Excitation purity (Pe): The excitation purity Pe is an excitation purity calculated according to JIS Z 8701:1999. (9) Viscosity: The temperature T 11 , where the viscosity η 10 11 dPa · s, and the temperature T 12 , where the viscosity η 10 12 dPa · s, were measured using a bar bending method, with the temperature T 11 and the temperature T 12 were the criterion for bending processability. (10) Relative density: The relative density of about 20 g of a glass mass containing no bubbles and cut from the glass plate was measured using the Archimedes method. (11) Young's modulus: Young's modulus was measured at 25 °C using an ultrasonic pulse method (Olympus, DL35) based on JIS R1602:1995 "Test Method for Elastic Modulus of Fine Ceramics". (12) Average coefficient of linear expansion at 50 °C to 350 °C (CTE 50-350 ): The average linear expansion coefficient was measured using a differential thermodilatometer (TMA) and was determined based on the specifications in JIS R3102:1995. The measurement results are shown in Table 1 and Table 2. It should be noted that in Table 1 and Table 2, "-" indicates that calculation is not possible because B2O3 is not included, and a blank space indicates that no measurement was performed. Table 1 Mol-% Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 SiO2 69,5 83,4 83,3 71,9 71,9 75,8 71,9 71,9 75,0 Al2O3 0,9 1,2 1,2 8,0 6,0 6,0 10,0 2,0 4,0 B2O3 0,0 11,6 11,5 12,0 16,0 12,0 8,0 18,0 13,0 MgO 7,1 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 CaO 9,1 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 3,5 Na2O 12,6 3,3 3,3 8,0 6,0 6,0 10,0 8,0 4,2 K2O 0,6 0,5 0,5 0,0 0,0 0,0 0,0 0,0 0,0 Fe2O3 0,18 0,02 0,19 0,20 0,20 0,20 0,20 0,20 0,19 SiO2 + Al2O3 + B2O3 [mol-%] 70 96 96 92 94 94 90 92 92 R2O [mol%] 13,2 3,8 3,7 8,0 6,0 6,0 10,0 8,0 7,8 B 3 [%] - 72 72 97 100 97 100 62 68 B 4 [%] - 28 28 3 0 3 0 38 32 B 3 as B2O3 [mol-%] - 8,4 8,4 11,6 16,0 11,6 8,0 11,2 8,8 B 4 as B2O3 [mol-%] - 3,2 3,2 0,4 0,0 0,4 0,0 6,8 4,2 Fe redox [%] 10 or more 10 or more 10 or more 10 or more 10 or more 10 or more 10 or more 10 or more Tv_D65 (ISO-9050:2003) [%] 86 94 75 72 68 66 73 83 77 Te (ISO-9050:2003) [%] 73 93 77 73 71 68 73 81 74 TÜV (ISO-9050:2003) [%] 47 85 36 10 5 7 18 45 37 L* (D65) 91,4 95,1 87,1 85,6 83,7 82,6 86,3 90,7 87,9 a* (D65) -2,6 -0,1 0,3 0,3 0,0 0,4 0,4 -0,4 0,0 b* (D65) 0,3 0,2 2,0 3,8 4,7 4,1 3,0 1,8 1,6 c* (D65) 2,6 0,2 2,1 3,8 4,7 4,1 3,0 1,9 1,6 Dw [nm] 500 571 580 579 578 579 580 575 577 Pe [%] 1,1 0,3 2,4 4,3 5,4 4,9 3,5 1,9 1,9 TV / Tele [-] 1,17 1,01 0,97 0,98 0,96 0,96 1,01 1,03 1,04 T 11 [°C] 613 650 650 T 12 [°C] 590 609 609 Relative density 2,51 2,23 2,23 2,27 2,22 2,23 2,31 2,28 2,27 Young's modulus [GPa] 74 64 64 59 55 58 63 65 69 CTE 50-350 [× 10 -7 / °C] 91 33 33 52 46 Table 1 (continued) Mol-% Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 SiO2 75,3 77,8 76,6 73,7 72,7 71,7 79,3 79,1 Al2O3 2,9 2,0 2,8 2,8 3,9 4,9 2,0 3,2 B2O3 12,3 12,0 11,3 13,2 13,2 13,2 11,5 10,0 MgO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 CaO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 Li2O 2,5 0,0 2,5 2,5 3,5 4,5 1,7 2,4 Na2O 6,8 8,0 6,3 7,3 6,3 5,3 5,1 4,5 K2O 0,2 0,0 0,2 0,2 0,2 0,2 0,2 0,5 Fe2O3 0,02 0,19 0,19 0,19 0,19 0,19 0,19 0,19 SiO2 + Al2O3 + B2O3 [mol-%] 90 92 91 90 90 90 93 92 R2O [mol%] 9,5 8,0 9,0 10,0 10,0 10,0 7,0 7,5 B 3 [%] 47 46 47 47 54 61 58 54 B 4 [%] 53 54 53 53 46 39 42 46 B 3 as B2O3 [mol-%] 5,8 5,5 5,3 6,2 7,2 8,1 6,7 5,4 B 4 as B2O3 [mol-%] 6,5 6,5 6,0 7,0 6,1 5,2 4,8 4,6 Fe redox [%] 24 10 or more 10 or more 10 or more 10 or more 10 or more 10 or more 10 or more Tv_D65 (ISO-9050:2003) [%] 92 85 82 83 82 80 81 81 Te (ISO-9050:2003) [%] 91 78 74 74 75 74 76 74 TÜV (ISO-9050:2003) [%] 80 52 48 48 44 40 45 46 L* (D65) 94,3 91,3 90,1 90,4 90,0 89,1 89,5 89,5 a* (D65) -0,2 -0,8 -1,0 -1,0 -0,7 -0,4 -0,4 -0,6 b* (D65) 0,2 1,0 0,8 0,7 1,0 1,3 1,3 1,1 c* (D65) 0,3 1,3 1,3 1,3 1,3 1,3 1,4 1,2 Dw [nm] 564 564 555 550 567 573 572 568 Pe [%] 0,3 1,0 0,6 0,4 1,0 1,3 1,4 1,1 TV / Tele [-] 1,01 1,10 1,12 1,12 1,09 1,07 1,07 1,08 T 11 [°C] 595 640 or less 599 589 581 640 or less 620 609 T 12 [°C] 565 570 561 555 592 578 Relative density 2,33 2,32 2,32 2,33 2,32 2,30 2,28 2,29 Young's modulus [GPa] 74 71 74 74 73 72 70 72 CTE 50-350 [× 10 -7 / °C] 54 49 40 or more 40 or more 40 or more 40 or more 40 or more 40 or more Table 2 Mol-% Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 SiO2 75,2 75,3 75,1 75,0 75,2 78,1 75,2 77,6 75,9 Al2O3 2,8 2,9 2,8 2,8 2,8 1,7 1,8 2,0 2,0 B2O3 12,3 12,3 12,3 12,3 12,3 13,0 13,7 12,2 12,0 MgO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 CaO 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 2,0 Li2O 2,5 2,5 2,5 2,5 2,5 0,8 0,0 0,0 0,0 Na2O 6,8 6,8 6,8 6,8 6,8 5,5 7,8 6,5 8,0 K2O 0,2 0,2 0,2 0,2 0,2 0,7 1,4 1,5 0,0 Fe2O3 0,19 0,10 0,29 0,39 0,15 0,19 0,20 0,20 0,19 SiO2 + Al2O3 + B2O3 [mol-%] 90 90 90 90 90 93 91 92 90 R2O [mol%] 9,5 9,5 9,5 9,5 9,5 7,0 9,2 8,0 8,0 B 3 [%] 47 47 47 47 47 55 41 50 43 B 4 [%] 53 53 53 53 53 45 59 50 57 B 3 as B2O3 [mol-%] 5,8 5,8 5,8 5,8 5,8 7,1 5,6 6,1 5,2 B 4 as B2O3 [mol-%] 6,5 6,5 6,5 6,5 6,5 5,9 8,1 6,1 6,8 Fe redox [%] 21 20 20 19 32 10 or more 10 or more 10 or more 10 or more Tv_D65 (ISO-9050:2003) [%] 85 90 78 69 86 84 85 85 86 Te (ISO-9050:2003) [%] 78 86 72 64 78 78 77 77 77 TÜV (ISO-9050:2003) [%] 46 62 33 22 54 50 53 54 43 L* (D65) 91,2 93,4 88,3 84,1 91,6 91,0 91,5 91,2 91,8 a* (D65) -0,9 -0,5 -1,0 -1,0 -0,9 -0,6 -1,0 -0,8 -1,2 b* (D65) 1,2 0,6 2,1 3,1 0,6 1,2 1,0 1,1 0,9 c* (D65) 1,5 0,8 2,3 3,2 1,1 1,4 1,4 1,3 1,5 Dw [nm] 565 562 570 573 550 569 560 565 553 Pe [%] 1,1 0,6 2,1 3,3 0,2 1,2 0,8 1,0 0,7 TV / Tele [-] 1,08 1,05 1,09 1,08 1,10 1,08 1,11 1,10 1,12 T 11 [°C] 595 595 595 595 595 640 or less 640 or less 640 or less 640 or less T 12 [°C] 565 565 565 565 565 Relative density 2,33 2,33 2,33 2,33 2,33 2,30 2,34 2,32 2,35 Young's modulus [GPa] 74 74 74 74 74 71 73 71 74 CTE 50-350 [× 10 -7 / °C] 54 54 54 54 54 40 or more 40 or more 40 or more 40 or more Table 2 (continued) Mol-% Example 27 Example 28 Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 Example 35 SiO2 75,9 75,9 70,0 70,0 75,2 75,2 75,2 77,8 75,2 Al2O3 2,0 2,0 1,9 1,9 2,8 2,8 1,5 2,6 1,5 B2O3 12,0 12,0 18,0 18,0 12,3 12,3 12,3 10,9 12,3 MgO 1,0 0,0 0,0 2,0 0,0 0,0 0,0 0,0 0,0 CaO 1,0 4,0 2,0 0,0 0,0 0,0 0,0 0,0 0,0 Li2O 0,0 0,0 0,0 0,0 2,5 2,5 3,4 0,0 0,0 Na2O 8,0 6,0 8,0 8,0 6,8 6,8 7,2 6,5 9,5 K2O 0,0 0,0 0,0 0,0 0,2 0,2 0,3 2,0 1,3 Fe2O3 0,19 0,19 0,20 0,19 0,19 0,19 0,19 0,19 0,19 SiO2 + Al2O3 + B2O3 [mol-%] 90 90 90 90 90 90 89 91 89 R2O [mol%] 8,0 6,0 8,0 8,0 9,5 9,5 10,8 8,5 10,8 B 3 [%] 47 49 56 59 47 47 23 51 24 B 4 [%] 53 51 44 41 53 53 77 49 76 B 3 as B2O3 [mol-%] 5,6 5,9 10,1 10,6 5,8 5,8 2,8 5,6 2,9 B 4 as B2O3 [mol-%] 6,4 6,1 7,9 7,4 6,5 6,5 9,5 5,3 9,1 Fe redox [%] 10 or more 10 or more 10 or more 10 or more 11 17 10 or more 10 or more 10 or more Tv_D65 (ISO-9050:2003) [%] 87 85 85 85 88 86 86 83 86 Te (ISO-9050:2003) [%] 78 78 80 80 84 81 77 74 75 TÜV (ISO-9050:2003) [%] 46 30 34 35 44 44 44 55 50 L* (D65) 91,9 91,4 91,3 91,3 92,4 91,8 91,7 90,6 91,8 a* (D65) -1,1 -1,2 -0,8 -0,7 -0,8 -0,7 -1,4 -1,0 -1,6 b* (D65) 1,1 1,5 1,6 1,8 1,7 1,2 0,8 0,8 0,6 c* (D65) 1,6 1,9 1,8 1,9 1,9 1,8 1,6 1,3 1,7 Dw [nm] 560 565 571 571 570 571 544 553 522 Pe [%] 0,9 1,4 1,6 1,8 1,7 1,8 0,6 0,8 0,4 TV / Tele [-] 1,10 1,10 1,07 1,06 1,05 1,07 1,12 1,13 1,15 T 11 [°C] 640 or less 640 or less 640 or less 640 or less 595 595 T 12 [°C] 565 565 Relative density 2,33 2,33 2,32 2,29 2,33 2,33 2,36 2,33 2,40 Young's modulus [GPa] 72 73 70 66 74 74 79 71 78 CTE 50-350 [× 10 -7 / °C] 40 or more 40 or more 40 or more 40 or more 54 54 58 56 64

[0185] The glasses in Example 11 to Example 35, which are examples of the present invention, have a sunlight transmittance Te of 90% or less, a dominant wavelength Dw of 520 nm or more and 574 nm or less, and an excitation purity Pe of 4.0% or less, have excellent heat shielding properties, and have designability.

[0186] On the other hand, the glass in Example 1, which is a comparative example, is free of B2O3, and thus has a dominant wavelength Dw of 500 nm, showing designability inferior to that in inventive examples.

[0187] Furthermore, the glass in Example 2, which is a comparative example, has a content of Fe2O3 of less than 0.03% and a proportion of tricoordinate boron of more than 61% and thus has a sunlight transmittance Te of 93%, which shows heat shielding properties inferior to those in inventive examples.

[0188] Furthermore, Example 3 and Examples 7 to 9, which are comparative examples, have a tricoordinate boron content of more than 61% and thus have a dominant wavelength Dw of more than 574 nm, showing designability inferior to that in inventive examples.

[0189] Furthermore, Example 4 to Example 6, which are comparative examples, have a tricoordinate boron content of more than 61% and thus have a dominant wavelength Dw of more than 574 nm and an excitation purity Pe of more than 4.0%, showing designability inferior to that in inventive examples.

[0190] Furthermore, the glass in Example 10 as a comparative example has a content of Fe2O3 of less than 0.03% and thus has a sunlight transmittance Te of 91%, which shows heat shielding properties inferior to those in inventive examples.

[0191] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to one skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Japanese Patent Application No. 2022-099058) filed on June 20, 2022, the contents of which are incorporated herein by reference. LIST OF REFERENCE SYMBOLS 10 Laminated glass 11 First glass plate 12 Second glass plate 13 Intermediate layer 100 motor vehicles 110 Opening 120 housings 150 rearview mirrors 201 millimeter wave radar 202 Stereo camera 300 radio waves QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP H09-301736 A

[0005] JP 2001-019470 A

[0005] US 2018 / 0194114 A1

[0005] JP H07-109147 A

[0005] JP H04-280834 A

[0005] WO 2016 / 093031

[0130] JP 2022-099058

[0191] Cited non-patent literature

[0000] JIS Z 8701:1999 [0022, 0023, 0034, 0035] ISO-9050:2003 [0033, 0089] JIS Z 8781-4:2003 [0111, 0112, 0113] ISO-13837:2008,

[0169] JIS Z 8781-4:2013 [0170, 0171]< / glaszusammensetzung>

Claims

[1] Alkali borosilicate glass, where a total iron content as Fe2O3 is 0.03% or more in mol% as oxides, a proportion of three-coordinate boron based on the total amount of three-coordinate boron and four-coordinate boron is 61% or less, the alkali borosilicate glass is essentially free of Se and CoO, when a thickness of the alkali borosilicate glass is converted to 2.0 mm, a solar transmittance Te, as specified in ISO-9050:2003, is 90% or less, a dominant wavelength Dw, ​​measured using a C standard light source specified in JIS Z 8701:1999, is 520 nm or more and 574 nm or less, and an excitation purity Pe, measured using the C standard light source specified in JIS Z 8701:1999, is 4.0% or less. [2] The alkali borosilicate glass according to claim 1, wherein a ratio (Tv / Te) is 1.05 or more when the thickness of the alkali borosilicate glass is converted to 2.0 mm, provided that Tv is a visible light transmittance specified in ISO-9050:2003 using a D65 light source, and Te is the sunlight transmittance specified in ISO-9050:2003. [3] The alkali borosilicate glass according to claim 1, wherein a visible light transmittance Tv specified in ISO-9050:2003 using a D65 light source is 75% or more when the thickness of the alkali borosilicate glass is converted to 2.0 mm. [4] The alkali borosilicate glass according to claim 1, wherein a visible light transmittance Tv specified in ISO-9050:2003 using a D65 light source is less than 75% when the thickness of the alkali borosilicate glass is converted to 2.0 mm. [5] The alkali borosilicate glass according to claim 1, wherein the content of total iron as Fe2O3 is 0.040% or more and 0.60% or less in mol% as oxides. [6] The alkali borosilicate glass according to claim 1, wherein a Young's modulus is 65 GPa or more. [7] Alkali borosilicate glass according to claim 1, wherein a temperature T 11 , where the glass viscosity is 10 11 (dPa s) is 640 °C or lower. [8] Alkali borosilicate glass according to claim 1, comprising, in mol% as oxides: 70% ≤ SiO2 ≤ 80%; 8.0% ≤ B2O3 ≤ 20%; 1.0% ≤ Al2O3 ≤ 5.0%; 0.0% ≤ Li2O ≤ 5.0%; 2.0% ≤ Na2O ≤ 10%; 0.0% ≤ K2O ≤ 5.0%; 0.0% ≤ MgO ≤ 5.0%; 0.0% ≤ CaO ≤ 5.0%; 0.0% ≤ SrO ≤ 5.0%; 0.0% ≤ BaO ≤ 5.0%; 89% ≤ SiO2 + B2O3 + Al2O3; and 5.0% ≤ Li2O + Na2O + K2O. [9] The alkali borosilicate glass according to claim 8, wherein the content of total iron as Fe2O3 is 0.040% or more and 0.60% or less in mol% as oxides, and a mass fraction of divalent iron as Fe2O3 in the total iron as Fe2O3 is 10% or more. [10] Alkali borosilicate glass according to claim 8, comprising Li2O. [11] A bent glass comprising the alkali borosilicate glass according to claim 1. [12] Laminated glass comprising: a first glass plate; a second glass plate; and an intermediate layer arranged between the first glass plate and the second glass plate, wherein the first glass plate is the alkali borosilicate glass according to any one of claims 1 to 10 or the bent glass according to claim 11. [13] The laminated glass according to claim 12, wherein the second glass plate is the alkali borosilicate glass according to any one of claims 1 to 10 or the bent glass according to claim 11. [14] The laminated glass according to claim 12, wherein the second glass plate is an alkali aluminosilicate glass comprising 1.0% or more of Al2O3 in mol% as oxides. [15] The laminated glass according to claim 12, wherein the second glass plate is an alkali aluminoborosilicate glass comprising 1.0% or more of Al2O3 and 1.0% or more of B2O3 in mol% as oxides. [16] The laminated glass according to claim 12, wherein the second glass sheet is a chemically strengthened glass. [17] The laminated glass according to claim 12, wherein the second glass sheet is a soda-lime glass. [18] A vehicle window pane comprising the alkali borosilicate glass according to any one of claims 1 to 10 or the bent glass according to claim 11. [19] A vehicle window pane comprising the laminated glass according to claim 12. [20] A window pane for construction purposes comprising the alkali borosilicate glass according to any one of claims 1 to 10 or the bent glass according to claim 11.

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