Glass, chemically strengthened glass and protective glass

Abstract

The present invention relates to glass, chemically strengthened glass and protective glass. The present invention relates to a glass, wherein the content of SiO2, Al2O3, Li2O, the total content of any one or more of Na2O and K2O, the ratio of the content of Li2O to the total amount of Li2O, Na2O and K2O, the total content of MgO, CaO, SrO, BaO and ZnO are within a specific range.

Description

[0001] This application is a divisional application of Chinese patent application No. 202080050734.4, filed on July 13, 2020. Technical Field

[0002] This invention relates to glass, chemically strengthened glass, and protective glass. Background Technology

[0003] In recent years, protective glass containing chemically strengthened glass has been used to protect display devices such as mobile phones, smartphones, and tablets, and to enhance their aesthetics.

[0004] In chemically strengthened glass, there is a tendency for higher surface compressive stress (CS) and compressive stress layer depth (DOL) to correlate with higher strength. On the other hand, internal tensile stress (CT) is generated within the glass to maintain equilibrium with the surface compressive stress; therefore, the higher the CS and DOL, the higher the CT. When glass with a high CT breaks, the number of fragments increases, and the risk of fragment scattering increases.

[0005] Patent Document 1 describes a stress distribution represented by curved lines formed by a two-step chemical strengthening process, thereby increasing the surface compressive stress (CS) while suppressing internal tensile stress (CT).

[0006] Furthermore, Patent Document 2 discloses a lithium aluminum silicate glass that achieves relatively high surface compressive stress and compressive stress layer depth through a two-step chemical strengthening process. This lithium aluminum silicate glass, through a two-step chemical strengthening process using sodium and potassium salts, can increase CS and DOL while suppressing CT.

[0007] On the other hand, touch panels used in smartphones and the like come into contact with fingers during use, making them prone to accumulating dirt such as fingerprints. Furthermore, operability when operating the touch panel with fingers is also required. Patent Document 3 describes the use of a fluorinated organosilicon compound as a coating to improve stain resistance and finger slippage.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: U.S. Patent Application Publication No. 2015 / 0259244

[0011] Patent Document 2: Japanese Patent Publication No. 2013-520388

[0012] Patent Document 3: Japanese Patent Application Publication No. 2000-144097 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] Lithium aluminum silicate glass tends to devitrify during glass manufacturing processes or during processes such as bending and shaping the resulting glass.

[0015] In addition, chemically strengthened glass obtained by ion exchange treatment of lithium aluminum silicate glass has a layer that improves anti-fouling properties and finger slip resistance (hereinafter referred to as the anti-fouling layer) that is easy to peel off.

[0016] The purpose of this invention is to provide a glass with excellent manufacturing properties and that inhibits the peeling of the anti-fouling layer.

[0017] means for solving problems

[0018] The inventors have studied lithium aluminum silicate glass and discovered characteristics of glass composition that result in excellent manufacturing properties. Furthermore, they investigated the peeling of the antifouling layer and found that a lower surface resistivity of the glass suppresses the tendency to peel. Additionally, they discovered that a higher frequency hopping frequency in chemically strengthened glass further suppresses the tendency to peel. Frequency hopping is the vibration frequency at which electrical conductivity is generated in the glass due to the jumping vibrations of charge carriers. Based on these findings, this invention was completed.

[0019] This invention provides a glass, wherein, based on the molar percentage of oxides, the glass contains:

[0020] 60%–75% SiO2,

[0021] 8%–20% Al2O3,

[0022] 5%–16% Li2O, and

[0023] The total amount of either Na₂O or K₂O is 2% to 15%, and

[0024] The ratio of Li2O content to the total amount of Li2O, Na2O, and K2O (P) Li Above 0.40, and

[0025] The combined content of MgO, CaO, SrO, BaO, and ZnO is 0–10%.

[0026] Additionally, a chemically strengthened glass is provided, wherein the surface compressive stress value of the chemically strengthened glass is 600 MPa or higher, and

[0027] The matrix glass composition of the chemically strengthened glass, based on oxides as a molar percentage, contains:

[0028] 60%–75% SiO2,

[0029] 8%–20% Al2O3,

[0030] 5%–16% Li2O, and

[0031] The total amount of either Na₂O or K₂O is 2% to 15%, and

[0032] The ratio of Li2O content to the total amount of Li2O, Na2O, and K2O (P) Li Above 0.40

[0033] The total content of MgO, CaO, SrO, BaO, and ZnO is 0-10%, and the frequency hopping of the chemically strengthened glass is 10. 2.8 Hz and above.

[0034] In addition, protective glass containing the aforementioned chemically strengthened glass is provided.

[0035] Invention Effects

[0036] According to the present invention, it is possible to provide a chemically strengthened glass that is not prone to devitrification, has a large surface compressive stress value (CS) and a large compressive stress layer depth (DOL), and whose organic layers such as antifouling layers are not easily peeled off. Attached Figure Description

[0037] Figure 1 A graph showing the relationship between the surface resistivity of unstrengthened glass and the contact angle of a water droplet after it has formed an antifouling layer and is worn under certain conditions.

[0038] Figure 2 This is a graph showing the relationship between the surface resistivity of chemically strengthened glass and the contact angle of a water droplet after it has formed an antifouling layer and is worn under certain conditions.

[0039] Figure 3 This is a graph showing the relationship between the frequency hopping of chemically strengthened glass and the contact angle of a water droplet after it has formed an antifouling layer and is worn under certain conditions.

[0040] Figure 4 This is a schematic top view of the electrode pattern used to measure surface resistivity.

[0041] Figure 5 A schematic top view showing the electrode pattern used for measuring surface resistivity in the embodiments. Figure 5 In the text, the unit for the length of each width is mm.

[0042] Figure 6 This is a schematic diagram of an electrode pattern used for measuring impedance. Detailed Implementation

[0043] The glass of the present invention will be described in detail below, but the present invention is not limited to the following embodiments. It can be implemented in any modified form without departing from the spirit of the present invention.

[0044] In this specification, "chemically strengthened glass" refers to glass that has undergone chemical strengthening treatment. Conversely, "chemically strengthened glass" refers to glass before undergoing chemical strengthening treatment.

[0045] In this specification, the glass composition of chemically strengthened glass is sometimes referred to as the matrix glass composition of chemically strengthened glass. In chemically strengthened glass, a compressive stress layer formed by ion exchange is usually formed on the glass surface; therefore, the glass composition of the portion that has not undergone ion exchange is consistent with the matrix glass composition of the chemically strengthened glass.

[0046] In this specification, the glass composition is expressed as a mole percentage based on oxides, and is sometimes simply referred to as %. Additionally, the "~" indicating a numerical range is used to indicate the lower and upper limits of the values ​​listed before and after it.

[0047] In glass composition, "substantially free of" means not containing any components other than unavoidable impurities present in raw materials, etc., i.e., not intentionally present. Specifically, components other than coloring agents are, for example, less than 0.1 mol%.

[0048] In this specification, "stress distribution" is a graph representing compressive stress values ​​as measured from the depth of the glass surface. Negative compressive stress values ​​refer to tensile stress.

[0049] In this specification, the "stress distribution" can be determined by combining an optical waveguide surface stress meter and a scattered light photoelastic stress meter.

[0050] Optical waveguide surface stress gauges can accurately measure the stress in glass in a short time. An example of an optical waveguide surface stress gauge is the FSM-6000 manufactured by Orihara. However, in principle, optical waveguide surface stress gauges can only measure stress when the refractive index decreases from the sample surface inwards. In chemically strengthened glass, the layer obtained by replacing sodium ions inside the glass with external potassium ions can have its stress measured using an optical waveguide surface stress gauge because the refractive index decreases from the sample surface inwards. However, the stress in the layer obtained by replacing lithium ions inside the glass with external sodium ions cannot be accurately measured using an optical waveguide surface stress gauge.

[0051] The method using a scattered light photoelastic stress meter allows for stress measurement independent of the refractive index distribution. An example of a scattered light photoelastic stress meter is the SLP1000 manufactured by Orihara Corporation. However, scattered light photoelastic stress meters are susceptible to surface scattering, and sometimes cannot accurately measure the stress near the surface.

[0052] Based on the above reasons, by combining the two measuring devices, the optical waveguide surface stress gauge and the scattered light photoelastic stress gauge, accurate stress measurement can be performed.

[0053] <Glass>

[0054] <<Composition>>

[0055] The glass in this embodiment (hereinafter sometimes referred to as "this glass") is preferably lithium aluminosilicate glass, which contains, in molar percentage based on oxides:

[0056] 60%–75% SiO2,

[0057] 8%–20% Al2O3, and

[0058] 5% to 16% Li2O.

[0059] The preferred glass composition will be described below.

[0060] SiO2 is a component that forms the network of glass. In addition, SiO2 is a component that improves chemical durability and reduces cracking when the glass surface is damaged.

[0061] The SiO2 content is preferably 60% or more, more preferably 63% or more, and particularly preferably 65% ​​or more. On the other hand, from the viewpoint of improving meltability, the SiO2 content is preferably 75% or less, more preferably 72% or less, even more preferably 70% or less, and particularly preferably 68% or less.

[0062] Al2O3 is a component that improves ion exchange performance during chemical strengthening and increases surface compressive stress after strengthening.

[0063] The Al2O3 content is preferably 8% or more, more preferably 9% or more, further preferably 10% or more, even more preferably 11% or more, and particularly preferably 12% or more. On the other hand, when the Al2O3 content is too high, crystals tend to grow easily during melting, which can easily lead to a decrease in yield due to devitrification defects. In addition, the high-temperature viscosity of the glass increases, making it difficult to melt. The Al2O3 content is preferably 20% or less, more preferably 18% or less, and even more preferably 16% or less.

[0064] Both SiO2 and Al2O3 are components that stabilize the structure of the glass. To reduce brittleness, the total content is preferably 65% ​​or more, more preferably 70% or more, and even more preferably 75% or more.

[0065] Both SiO2 and Al2O3 tend to increase the melting temperature of glass. Therefore, in order to facilitate melting, their combined content is preferably 90% or less, more preferably 87% or less, even more preferably 85% or less, and particularly preferably 82% or less.

[0066] Li₂O is a component that generates surface compressive stress through ion exchange and improves the meltability of glass. By chemically strengthening glass with Li₂O, and utilizing the ion exchange between Li ions on the glass surface and Na ions on the outside, as well as the ion exchange between Na ions and K ions on the outside, a stress distribution with high surface compressive stress and a high compressive stress layer is obtained. From the viewpoint of easily obtaining an optimal stress distribution, the Li₂O content is preferably 5% or more, more preferably 7% or more, further preferably 9% or more, particularly preferably 10% or more, and most preferably 11% or more.

[0067] On the other hand, when the Li2O content is too high, the crystal growth rate during glass forming increases, which can easily lead to a decrease in quality due to devitrification. The Li2O content is preferably 20% or less, more preferably 16% or less, even more preferably 14% or less, and particularly preferably 12% or less.

[0068] Neither Na₂O nor K₂O is essential, but both are components that improve the meltability of glass and reduce the crystal growth rate during glass forming. Furthermore, to improve ion exchange performance, it is preferable to contain small amounts of Na₂O and K₂O.

[0069] Na₂O is a component that forms a surface compressive stress layer during chemical strengthening treatment using potassium salts, and also a component that reduces glass adhesion. To achieve this effect, the Na₂O content is preferably 1% or more, more preferably 2% or more, further preferably 3% or more, even more preferably 4% or more, and particularly preferably 5% or more. On the other hand, from the viewpoint of avoiding a decrease in surface compressive stress (CS) during strengthening treatment using sodium salts, the Na₂O content is preferably 10% or less, more preferably 8% or less, further preferably 6% or less, and particularly preferably 5% or less.

[0070] To improve ion exchange performance, K₂O may be included. When K₂O is included, its content is preferably 0.1% or more, more preferably 0.15% or more, and particularly preferably 0.2% or more. To effectively prevent devitrification, the K₂O content is preferably 0.5% or more, more preferably 1.2% or more. On the other hand, excessive K₂O can easily reduce the brittleness of the glass. Furthermore, the efficiency of chemical strengthening may sometimes decrease. The K₂O content is preferably 5% or less, more preferably 3% or less, further preferably 1% or less, and particularly preferably 0.5% or less.

[0071] The total content of Na2O and K2O ([Na2O]+[K2O]) is preferably 2% to 15%, more preferably 3% or more, and even more preferably 4% or more. On the other hand, the total content is more preferably 10% or less, more preferably 8% or less, even more preferably 6% or less, even more preferably 5% or less, and particularly preferably 4% or less.

[0072] In addition, the Na2O content is preferably greater than the K2O content. K2O tends to increase surface resistivity.

[0073] To reduce surface resistivity, P Li The content ratio expressed as [Li₂O] / ([Li₂O]+[Na₂O]+[K₂O]) is preferably 0.40 or more, more preferably 0.50 or more, and even more preferably 0.60 or more. On the other hand, in order to suppress devitrification during glass melting, the above ratio is preferably 0.90 or less, and particularly preferably 0.80 or less.

[0074] To suppress devitrification, P Na The content ratio represented by [Na2O] / ([Li2O]+[Na2O]+[K2O]) is preferably 0.1 or more, more preferably 0.2 or more. In order to reduce the surface resistivity, the above ratio is preferably 0.5 or less, more preferably 0.4 or less.

[0075] To reduce surface resistivity, P K The ratio of [K2O] / ([Li2O]+[Na2O]+[K2O]) is preferably 0.3 or less, more preferably 0.2 or less. There is no particular limitation on the lower limit of the above ratio, and it may also be 0.

[0076] Furthermore, from the viewpoint of reducing the growth rate of devitrified crystals, the content ratio expressed as ([Al2O3]+[Li2O]) / ([Na2O]+[K2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO]+[ZrO2]+[Y2O3]) is preferably 5 or less, more preferably 4 or less, even more preferably 3.5 or less, and particularly preferably 3 or less.

[0077] From the viewpoint of reducing surface resistivity, the content ratio expressed as [Al2O3] / ([Li2O]+[Na2O]+[K2O]) is preferably 0.6 or more, more preferably 0.7 or more, and even more preferably 0.8 or more. On the other hand, in order to improve devitrification characteristics, the above ratio is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0078] From the viewpoint of increasing the surface compressive stress in the chemical strengthening treatment using sodium salt, the content ratio expressed as ([Al2O3]+[Li2O]) / ([Na2O]+[K2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO]+[ZrO2]+[Y2O3]) is preferably 1 or more, more preferably 1.5 or more, and even more preferably 2 or more.

[0079] To reduce viscosity during melting, MgO may be included. The MgO content is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more. On the other hand, when the MgO content is too high, it is difficult to increase the compressive stress layer during chemical strengthening treatment. The MgO content is preferably 10% or less, more preferably 8% or less, and particularly preferably 6% or less.

[0080] In the presence of MgO, in order to adjust the viscosity during glass manufacturing, the total content of MgO, SiO2, and Al2O3 [SiO2]+[Al2O3]+[MgO] is preferably 85% or less, more preferably 83% or less, and even more preferably 82% or less.

[0081] On the other hand, in order to reduce the brittleness of the glass, the total content mentioned above is preferably 70% or more, more preferably 73% or more, and even more preferably 75% or more.

[0082] MgO, CaO, SrO, BaO, and ZnO are not essential, but from the viewpoint of improving glass stability, they can be included. The total content of these elements [MgO]+[CaO]+[SrO]+[BaO]+[ZnO] is preferably 0.1% or more, more preferably 0.2% or more. To improve the brittleness of the glass, [MgO]+[CaO]+[SrO]+[BaO]+[ZnO] is preferably 10% or less, more preferably 5% or less, further preferably 3% or less, and even more preferably less than 1%.

[0083] To improve the stability of the glass, it is more preferable to contain at least one of MgO and CaO, and even more preferably, MgO. The total content of MgO and CaO is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1.0% or more. To improve the chemical strengthening properties, the total content of MgO and CaO is preferably 3% or less, more preferably 2% or less.

[0084] Since ZnO, SrO, and BaO tend to deteriorate chemical strengthening properties, the total content of [ZnO] + [SrO] + [BaO] is preferably 1.5% or less, more preferably 1.0% or less, and even more preferably 0.5% or less, to facilitate chemical strengthening. Furthermore, to improve the brittleness of the glass, [ZnO] + [SrO] + [BaO] is preferably less than 1%. There is no particular limitation on the lower limit of the above total content, and ZnO, SrO, and BaO may be absent.

[0085] CaO is a component that improves the meltability of glass and may be present. When CaO is present, the CaO content is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.5% or more. On the other hand, when the CaO content is excessive, it is difficult to increase the compressive stress value during chemical strengthening treatment. The CaO content is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and even more preferably 0.5% or less.

[0086] SrO is a component that improves the meltability of glass and may be present. When SrO is present, the SrO content is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.5% or more. On the other hand, when the SrO content is excessive, it is difficult to increase the compressive stress value during chemical strengthening treatment. The SrO content is preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, and particularly preferably 0.5% or less.

[0087] BaO is a component that improves the melt flowability of glass and may be present. When BaO is present, the BaO content is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.5% or more. On the other hand, when the BaO content is excessive, it is difficult to increase the compressive stress value during chemical strengthening treatment. The BaO content is preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, and particularly preferably 0.5% or less.

[0088] ZnO is a component that improves the meltability of glass and may be present. When ZnO is present, its content is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.5% or more. On the other hand, when the ZnO content is excessive, it is difficult to increase the compressive stress value during chemical strengthening treatment. The ZnO content is preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, and particularly preferably 0.5% or less.

[0089] While ZrO2 may not be present, its presence is preferred from the viewpoint of increasing the surface compressive stress of chemically strengthened glass. The ZrO2 content is preferably 0.1% or more, more preferably 0.15% or more, further preferably 0.2% or more, even more preferably 0.25% or more, and particularly preferably 0.3% or more. On the other hand, excessive ZrO2 content can easily lead to devitrification defects, making it difficult to increase the compressive stress value during chemical strengthening treatment. The ZrO2 content is preferably 2% or less, more preferably 1.5% or less, further preferably 1% or less, and particularly preferably 0.8% or less.

[0090] Y2O3 is not essential, but it is preferred to contain Y2O3 in order to increase the surface compressive stress of chemically strengthened glass and reduce the crystal growth rate.

[0091] Furthermore, to increase the fracture toughness value, it is preferable to contain any one or more of Y₂O₃, La₂O₃, and ZrO₂ in a total of 0.2% or more. The total content of Y₂O₃, La₂O₃, and ZrO₂ is preferably 0.5% or more, more preferably 1.0% or more, and even more preferably 1.5% or more. In addition, to lower the liquidus temperature and suppress devitrification, the total content is preferably 8% or less, more preferably 6% or less, even more preferably 5% or less, and even more preferably 4% or less.

[0092] In order to suppress devitrification, i.e. to lower the liquid phase temperature, the total content of Y2O3 and La2O3 is preferably greater than the content of ZrO2, and more preferably the content of Y2O3 is greater than the content of ZrO2.

[0093] The content of Y2O3 is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and particularly preferably 1% or more. On the other hand, when there is too much Y2O3, it is not easy to increase the compressive stress layer during chemical strengthening treatment. The content of Y2O3 is preferably 5% or less, more preferably 3% or less, even more preferably 2% or less, and particularly preferably 1.5% or less.

[0094] Although La2O3 is not essential, it may be included for the same reasons as Y2O3. The content of La2O3 is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and particularly preferably 0.8% or more. On the other hand, when there is too much La2O3, the compressive stress layer is not easily increased during chemical strengthening treatment; therefore, the content of La2O3 is preferably 5% or less, more preferably 3% or less, even more preferably 2% or less, and particularly preferably 1.5% or less.

[0095] TiO2 is a component highly effective in suppressing the solar radiation effect of glass, and therefore may be present. When TiO2 is present, its content is preferably 0.02% or more, more preferably 0.03% or more, even more preferably 0.04% or more, even more preferably 0.05% or more, and particularly preferably 0.06% or more. On the other hand, from the viewpoint of preventing devitrification and thus reducing the quality of chemically strengthened glass, the TiO2 content is preferably 1% or less, more preferably 0.5% or less, and even more preferably 0.25% or less.

[0096] B2O3 is not essential, but it can be included to reduce the brittleness of the glass, improve its resistance to chipping, or enhance its meltability. To reduce brittleness, the B2O3 content is preferably 0.5% or more, more preferably 1% or more, and even more preferably 2% or more. On the other hand, excessive B2O3 content can negatively impact acid resistance, therefore, it is preferably 10% or less. The B2O3 content is more preferably 6% or less, even more preferably 4% or less, and particularly preferably 2% or less. From the viewpoint of preventing the formation of ripples during melting, it is more preferable to have virtually no B2O3.

[0097] P2O5 is not essential, but it can be included to increase the compressive stress layer during chemical strengthening. When P2O5 is included, its content is preferably 0.5% or more, more preferably 1% or more, and even more preferably 2% or more. On the other hand, from the viewpoint of improving acid resistance, the P2O5 content is preferably 6% or less, more preferably 4% or less, and even more preferably 2% or less. From the viewpoint of preventing the formation of ripples during melting, it is more preferable that P2O5 is substantially absent.

[0098] The total content of B2O3 and P2O5 is preferably 0 to 10%, more preferably 1% or more, and even more preferably 2% or more. The total content of B2O3 and P2O5 is more preferably 6% or less, and even more preferably 4% or less.

[0099] Nb₂O₅, Ta₂O₅, Gd₂O₃, and CeO₂ have the effect of suppressing the sunlight effect on glass and are components that improve melt flowability. These components can be present in glass. When present, the content of each component is preferably 0.03% or more, more preferably 0.1% or more, further preferably 0.5% or more, even more preferably 0.8% or more, and particularly preferably 1% or more. On the other hand, when their content is too high, it is not easy to increase the compressive stress value during chemical strengthening treatment; therefore, it is preferably 3% or less, more preferably 2% or less, further preferably 1% or less, and particularly preferably 0.5% or less.

[0100] Fe2O3 absorbs heat rays, thus improving the meltability of glass. In the case of large-scale glass production using large melting furnaces, the presence of Fe2O3 is preferable. In this case, the Fe2O3 content, based on oxide weight%, is preferably 0.002% or more, more preferably 0.005% or more, even more preferably 0.007% or more, and particularly preferably 0.01% or more. On the other hand, when excessive Fe2O3 is present, coloring occurs. Therefore, from the viewpoint of improving glass transparency, its content, based on oxide weight%, is preferably 0.3% or less, more preferably 0.04% or less, even more preferably 0.025% or less, and particularly preferably 0.015% or less.

[0101] It should be noted that while all iron oxides in the glass are described here as Fe2O3, in reality, oxidized Fe(III) and reduced Fe(II) usually coexist in a mixture. Fe(III) produces a yellow color, Fe(II) produces a blue color, and in equilibrium, the glass produces a green color.

[0102] Furthermore, other coloring components can be added within a range that does not hinder the achievement of the desired chemical strengthening properties. Examples of preferred coloring components include Co3O4, MnO2, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, CeO2, Er2O3, and Nd2O3.

[0103] The total content of coloring components containing Fe2O3, based on the molar percentage of oxides, is preferably 5% or less. When the total content of coloring components containing Fe2O3 exceeds 5%, the glass may become devitrified. The content of coloring components is preferably 3% or less, more preferably 1% or less. Ideally, these components should be substantially absent if it is desired to improve the transmittance of the glass.

[0104] It may contain appropriate amounts of SO3, chlorides, fluorides, etc., as clarifying agents during glass melting. Preferably, it does not contain As2O3. When Sb2O3 is present, it is preferably 0.3% or less, more preferably 0.1% or less, and most preferably does not contain Sb2O3.

[0105] When the parameter X, calculated from the content (mol%) of each component using the following formula, is 0.70 or higher, the glass is less prone to severe breakage, and is therefore preferred. X is more preferably 0.75 or higher, even more preferably 0.80 or higher, and particularly preferably 0.83 or higher. Additionally, it is typically 1.5 or lower.

[0106] X=0.00866×[SiO2]+0.00724×[Al2O3]+0.00526×[MgO]+0.00444×

[0107] [CaO]+0.00797×[ZnO]+0.0122×[ZrO2]+0.0172×[Y2O3]+0.009×[Li2O]+0.00163×[Na2O]-0.00384×[K2O]

[0108] <<Peel resistance of the antifouling layer>>

[0109] The inventors investigated the peel resistance of an antifouling layer when a layer containing a fluorinated organic compound is formed on the surface of chemically strengthened glass as an antifouling layer. The results showed that the surface resistivity of the chemically strengthened glass is related to the peel resistance of the antifouling layer.

[0110] The peel resistance of an antifouling layer can be evaluated as follows: an antifouling layer is formed on a glass surface, and then "rubber abrasion" is performed before measuring the contact angle of a water droplet. Generally speaking, the larger the water contact angle after rubber abrasion, the better the antifouling layer maintains its function, and the superior its peel resistance.

[0111] Specifically, the peel resistance of the antifouling layer can be evaluated, for example, by measuring the contact angle of water droplets after rubber friction wear.

[0112] (Rubber friction wear)

[0113] A cylindrical rubber with a diameter of 6 mm is mounted on an abrasion tester and rubbed against the surface of the anti-fouling layer 7500 times under the conditions of a load of 1 kgf, a stroke width of 40 mm, a speed of 40 rpm, 25 °C, and 50% RH, until the layer is worn down.

[0114] (Water contact angle measurement)

[0115] A drop of pure water, approximately 1 μL, is dropped onto the surface after it has been abraded by rubber friction. The water contact angle (i.e., the water contact angle) is measured using a contact angle meter. It can be said that the larger the water contact angle after abrasion, the better the peel resistance of the antifouling layer.

[0116] Figure 1 A graph showing the relationship between the surface resistivity of an unstrengthened glass plate measured using the method described below and the water contact angle measured using the same method after rubber friction abrasion. Figure 1 It is known that the smaller the surface resistivity, the larger the water contact angle, and the better the peel resistance of the antifouling layer.

[0117] Frequency Hopping

[0118] Figure 2 This graph illustrates the relationship between surface resistivity and the peel resistance, or adhesion, of the antifouling layer on chemically strengthened glass. Figure 1 Similarly, it can be seen that the lower the surface resistivity, the larger the water contact angle, and the better the adhesion of the antifouling layer. However, the correlation between surface resistivity and the adhesion of the antifouling layer is not as clear as that between untreated glass.

[0119] Regarding this point, the inventors considered the following.

[0120] The adhesion of the antifouling layer depends on the electrical properties of the glass, which in turn depend on the ease with which charges can move from the glass surface; in other words, it depends on the electrical conductivity of the glass surface. The surface resistivity, or conductivity, of the glass depends on the type and amount of alkaline components present on the glass surface.

[0121] On the other hand, the adhesion of the antifouling layer and the electrical properties of glass are affected not only by the conductivity of the glass surface but also by the conductivity within the glass. In chemically strengthened glass, due to the influence of ion exchange treatment, the alkaline components present on the glass surface differ from those present inside the glass. Therefore, the conductivity differs between the surface and interior of the glass, weakening the relationship between the surface resistivity of the glass and the peel resistance of the antifouling layer.

[0122] Furthermore, the adhesion of antifouling layers is mostly evaluated using rubber friction and abrasion tests. It is considered that, for the charge generated during rubber friction, evaluation using alternating current (AC) is more appropriate than direct current (DC) evaluation.

[0123] Therefore, the inventors believe that, in order to consider the sealing of the anti-fouling layer, the admittance model of the capacitor element in the AC circuit should be studied compared with the surface resistance value of DC, and the complex admittance of the glass should be examined.

[0124] Complex admittance Y associated with ion-conducting materials * (ω), as a variable of frequency ω, is known as the following model formula known as the Almond-West formula (Reference: Journal of Materials Science, Vol. 19, 1984: pp. 3236-3248).

[0125]

[0126] Here, A1, B1, A2, and B2 are described as follows.

[0127]

[0128] B1=A1tan(n1π / 2) (15)

[0129]

[0130] B² = A²tan(n²π / 2) (17)

[0131] The inventors examined this relation in the following manner.

[0132] The complex admittance of glass is determined by constants K, n1, n2, and C. ∞ and frequency hopping ω p Therefore, it is believed that the charging characteristics of glass depend on the frequency hopping; if the frequency hopping is increased, it becomes difficult to charge.

[0133] The complex admittance of the glass plate was measured using an impedance analyzer, and the frequency hopping was determined by fitting the above equation (13) (Almond-West equation).

[0134] Figure 3 A graph showing the relationship between the frequency hopping measured using the method described later and the water contact angle after rubber friction wear, measured using the method described above, for chemically strengthened glass. Figure 3 It is known that the higher the hopping frequency, the larger the water contact angle, and the better the peel resistance of the antifouling layer.

[0135] It should be noted that for untreated glass, since there is a linear relationship between surface resistivity and frequency hopping, there is a correlation between frequency hopping and the peel resistance of the antifouling layer.

[0136] The chemically strengthened glass of this embodiment (hereinafter also referred to as the chemically strengthened glass) obtained by chemically strengthening the glass using the following method has a measured frequency hopping of 10. 2.8 Hz or higher, preferably 10 Hz 3.0 Hz or higher, more preferably 10 Hz 3.5 At frequencies above Hz, it is difficult to charge the glass. However, glass with excessively high frequency hopping tends to devitrify and has low fracture toughness. The preferred frequency hopping for this chemically strengthened glass is 10 Hz. 6.0 Hz or below, more preferably 10 Hz 5.5 Hz or below, more preferably 10 Hz 5.0 Below Hz.

[0137] (Methods for determining frequency hopping)

[0138] The glass plate is processed into a plate shape of 50mm × 50mm × 0.7mm, and a layer is formed on one surface. Figure 6 The electrode pattern shown.

[0139] The impedance at 20MHz to 2MHz was measured using an impedance analyzer, and the complex admittance was then determined.

[0140] <<Entropy Function>>

[0141] The inventors have also discovered that for unstrengthened glass, surface resistivity depends on the entropy function S. The glass exhibits a small value for the entropy function S (also simply referred to as the S value), resulting in low surface resistivity and excellent peel resistance of the antifouling layer.

[0142] S = -P Li ×log 10 (P Li )-P Na ×log 10 (P Na )-P K ×log 10 (P K )

[0143] Here,

[0144] P Li =[Li2O] / ([Li2O]+[Na2O]+[K2O])

[0145] P Na =[Na2O] / ([Li2O]+[Na2O]+[K2O])

[0146] P K =[K2O] / ([Li2O]+[Na2O]+[K2O])

[0147] Wherein, [Li₂O], [Na₂O], and [K₂O] represent the mol% content of Li₂O, Na₂O, and K₂O, respectively, based on oxides. It should be noted that the same applies to other components described below.

[0148] The S value of this glass is preferably 0.37 or less, more preferably 0.35 or less, even more preferably 0.3 or less, and even more preferably 0.28 or less. Furthermore, there is no particular limitation on the lower limit, and it is generally 0.15 or more.

[0149] The S-value of the matrix glass composition of the chemically strengthened glass preferably meets the range of the S-values ​​of the glass described above.

[0150] <<Surface Resistivity>>

[0151] To reduce the electric charge on the glass surface, the surface resistivity of the unstrengthened glass at 50°C is preferably 10. 13 Ω / □ or less, more preferably 10 12.5 Ω / □ or less, more preferably 10 12 Ω / □ or less. On the other hand, glasses with low charge tend to have poor devitrification properties during manufacturing; therefore, the surface resistivity of this glass at 50°C is preferably, for example, 10. 8Ω / □ or higher, more preferably 10 8.5 Ω / □ or higher, more preferably 10 9 Ω / □ and above.

[0152] To reduce the electric charge on the glass surface, the surface resistivity of the chemically strengthened glass at 50°C is preferably 10. 15 Ω / □ or less, more preferably 10 14.5 Ω / □ or less, more preferably 10 14 Ω / □ or less, especially preferably 10 13.5 Ω / □ or less, the optimal value is 10. 13 Below Ω / □. Surface resistivity, for example, is 10. 8 Ω / □ or higher, preferably 10 8.5 Ω / □ or higher, more preferably 10 9 Ω / □ or higher, preferably 10 10.5 Ω / □ or higher, the optimal value is 10. 11 Ω / □ and above.

[0153] Surface resistivity can be measured using the methods described later in the embodiments. A schematic top view of the comb electrode 1 used for measuring surface resistivity is shown in... Figure 4 In. Figure 4 In the middle, the comb electrode 1 has a shape in which a first comb electrode 11 and a second comb electrode 12 are arranged opposite each other in a way that the teeth of the comb are interleaved.

[0154] The surface resistivity ρ is calculated from the resistance value R and the electrode coefficient r in the form ρ = R × r. The resistance value R is calculated from the current value I and voltage V measured using comb electrodes in the form R = V / I. The electrode coefficient r is calculated from the ratio of the length of each electrode to the length between the electrodes. For Figure 4 The electrode coefficient of the comb-shaped electrode 1 is calculated by r = (W3 / W2) × 8 + (W1 / W4) × 7. The electrode coefficient r of the comb-shaped electrode 1 is, for example, 100 to 130.

[0155] The metal constituting the comb-shaped electrode 1 is, for example, a material with low electrical resistance such as platinum, aluminum, or gold. Platinum is preferred as the metal constituting the comb-shaped electrode 1. The comb-shaped electrode 1 is formed, for example, by preparing an electrically insulating substrate and forming a metal film constituting the comb-shaped electrode on the substrate by methods such as sputtering, vacuum evaporation, or plating.

[0156] <<Fracture Toughness Value>>

[0157] The fracture toughness value K1c of this glass is preferably 0.70 MPa·m. 1 / 2 The above, more preferably 0.75 MPa·m 1 / 2 The above is further preferably 0.80 MPa·m1 / 2 The above, particularly preferred, is 0.83 MPa·m 1 / 2 That's all. Additionally, the fracture toughness value is typically 2.0 MPa·m. 1 / 2 The following is typically 1.5 MPa·m 1 / 2 The following is a summary of the main points. Due to its high fracture toughness, even with the introduction of large surface compressive stress into the glass through chemical strengthening, it is not prone to violent breakage.

[0158] Fracture toughness values ​​can be determined using, for example, the DCDC method (Acta metall.mater. Vol. 43, pp. 3453-3458, 1995).

[0159] The preferred β-OH value of this glass is 0.1 mm. -1 The above, more preferably 0.15mm -1 The above is further preferred to be 0.2mm. -1 The above is particularly preferred, with 0.22mm being the optimal size. -1 The optimal value is 0.25mm. -1 above.

[0160] The β-OH value is an indicator of the moisture content in glass. Glass with a high β-OH value tends to have a lower softening point and is easier to bend and process. On the other hand, from the viewpoint of improving the strength of glass through chemical strengthening, when the β-OH value of the glass increases, the surface compressive stress (CS) after chemical strengthening treatment decreases, making it difficult to improve strength. Therefore, a β-OH value of 0.5 mm is preferred. -1 The following is more preferably 0.4mm -1 Hereinafter, 0.3mm is further preferred. -1 the following.

[0161] From the viewpoint of preventing glass breakage, the Young's modulus of this glass is preferably 80 GPa or higher, more preferably 82 GPa or higher, even more preferably 84 GPa or higher, and particularly preferably 85 GPa or higher. There is no particular upper limit on the Young's modulus, but glass with a high Young's modulus sometimes exhibits reduced acid resistance; therefore, it is, for example, below 110 GPa, preferably below 100 GPa, and more preferably below 90 GPa. The Young's modulus can be measured, for example, using the ultrasonic pulse method.

[0162] To reduce the weight of the product, the density of this glass is preferably 3.0 g / cm³. 3 The preferred value is 2.8 g / cm³. 3 The following is a further preferred value: 2.6 g / cm³ 3 The following is particularly preferred: 2.55 g / cm³ 3The following is a general guideline. There is no specific limit to the lower limit of density, but glass with low density tends to have lower acid resistance, etc., therefore, for example, 2.3 g / cm³. 3 The above, preferably 2.4 g / cm³ 3 The above, especially preferred, is 2.45 g / cm³. 3 above.

[0163] From the viewpoint of reducing surface reflection of visible light, the refractive index of this glass is preferably 1.6 or less, more preferably 1.58 or less, even more preferably 1.56 or less, and particularly preferably 1.54 or less. There is no particular limitation on the lower limit of the refractive index, but glass with a low refractive index tends to have low acid resistance, so for example, it is 1.5 or more, preferably 1.51 or more, and more preferably 1.52 or more.

[0164] From the viewpoint of reducing optical distortion, the photoelastic constant of this glass is preferably 33 nm / cm / MPa or less, more preferably 32 nm / cm / MPa or less, even more preferably 31 nm / cm / MPa or less, and particularly preferably 30 nm / cm / MPa or less. Furthermore, since glasses with low photoelastic constants tend to have low acid resistance, the photoelastic constant of this glass is, for example, 24 nm / cm / MPa or more, more preferably 25 nm / cm / MPa or more, and even more preferably 26 nm / cm / MPa or more.

[0165] From the viewpoint of reducing warpage after chemical strengthening, the average linear coefficient of thermal expansion (coefficient of thermal expansion) of this glass from 50℃ to 350℃ is preferably 95×10⁻⁶. -7 Below / ℃, more preferably 90×10 -7 Below / ℃, 88×10 is further preferred. -7 Below / ℃, 86×10 is particularly preferred. -7 Below / ℃, the optimal value is 84×10. -7 Below / ℃. There is no particular limit to the lower limit of the coefficient of thermal expansion, but glass with a small coefficient of thermal expansion is sometimes difficult to melt. Therefore, the average linear coefficient of thermal expansion (coefficient of thermal expansion) of this glass from 50℃ to 350℃ is, for example, 60 × 10⁻⁶. -7 / ℃ or above, preferably 70×10 -7 / ℃ or higher, more preferably 74×10 -7 / ℃ or higher, more preferably 76×10 -7 / ℃ or above.

[0166] From the viewpoint of reducing warpage after chemical strengthening, the glass transition temperature (Tg) is preferably 500°C or higher, more preferably 520°C or higher, and even more preferably 540°C or higher. From the viewpoint of facilitating float forming, it is preferably 750°C or lower, more preferably 700°C or lower, even more preferably 650°C or lower, particularly preferably 600°C or lower, and most preferably 580°C or lower.

[0167] Viscosity reaches 10 2 The temperature (T2) at dPa·s is preferably below 1750°C, more preferably below 1700°C, even more preferably below 1675°C, and particularly preferably below 1650°C. Temperature (T2) is a standard temperature used as the melting temperature of glass, and there is a tendency that the lower the T2, the easier it is to manufacture glass. There is no particular limitation on the lower limit of T2, but glass with a low T2 tends to have an excessively low glass transition temperature; therefore, T2 is typically above 1400°C, and preferably above 1450°C.

[0168] In addition, the viscosity reaches 10 4 The temperature (T4) at dPa·s is preferably 1350°C or lower, more preferably 1300°C or lower, even more preferably 1250°C or lower, and particularly preferably 1150°C or lower. Temperature (T4) is a standard temperature used to form glass into a sheet shape. Glass with a high T4 tends to place a higher load on the forming equipment. There is no particular limitation on the lower limit of T4, but glass with a low T4 tends to have an excessively low glass transition temperature. Therefore, T4 is typically 900°C or higher, preferably 950°C or higher, and more preferably 1000°C or higher.

[0169] When the devitrification temperature of this glass reaches a specific viscosity of 10... 4 A temperature below 120°C above the temperature (T4) at dPa·s is preferred as it is less prone to devitrification during float forming. A devitrification temperature is more preferably below 100°C above T4, even more preferably below 50°C above T4, and particularly preferably below T4.

[0170] The softening point of this glass is preferably below 850°C, more preferably below 820°C, and even more preferably below 790°C. This is because the lower the softening point of the glass, the lower the heat treatment temperature during bending, the lower the energy consumption, and the smaller the load on the equipment. From the viewpoint of reducing the bending temperature, a lower softening point is preferred, but in typical glass it is above 700°C. Glass with a softening point that is too low tends to have a tendency to relax the stress introduced during chemical strengthening treatment and to become low in strength; therefore, a softening point of 700°C or higher is preferred. More preferably, it is above 720°C, and even more preferably above 740°C. The softening point can be determined using the fiber elongation method described in JIS R 3103-1:2001.

[0171] Preferably, the crystallization peak temperature of this glass, as measured by the following method, is higher than (softening point -100°C). Furthermore, it is more preferable that no crystallization peak is observed.

[0172] The crystallization peak temperature was determined as follows: approximately 70 mg of glass was crushed in an agate mortar, the heating rate was adjusted to 10 °C / min, and the temperature was measured using a differential scanning calorimeter (DSC) at temperatures ranging from room temperature to 1000 °C.

[0173] The glass of this embodiment can be manufactured using conventional methods. For example, raw materials for preparing the various components of the glass are heated and melted in a glass melting furnace. Then, the glass is homogenized using known methods, shaped into a desired shape such as a glass sheet, and slowly cooled.

[0174] Examples of glass forming methods include float glass, pressing glass, fusion glass, and drawing glass. Float glass, which is particularly suitable for mass production, is especially preferred. Continuous forming methods other than float glass, such as fusion glass and drawing glass, are also preferred.

[0175] Then, the formed glass is ground and polished as needed to form a glass substrate. It should be noted that when the glass substrate is cut into a specified shape and size or when the glass substrate is chamfered, it is preferable to cut or chamfer the glass substrate before performing the chemical strengthening treatment described later, so that a compressive stress layer is also formed on the end face by the subsequent chemical strengthening treatment.

[0176] <Chemical strengthened glass>

[0177] The matrix glass composition of this chemically strengthened glass is the same as that of the glass described above. The surface compressive stress value of this chemically strengthened glass is preferably 600 MPa or more, more preferably 700 MPa or more, and even more preferably 800 MPa or more.

[0178] This chemically strengthened glass can be manufactured by chemically strengthening the obtained glass sheet, followed by cleaning and drying.

[0179] Chemical strengthening treatment can be carried out using well-known methods. In chemical strengthening treatment, a glass plate is brought into contact with a molten metal salt (e.g., potassium nitrate) containing metal ions with large ionic radii (typically K ions) by means of impregnation. As a result, the metal ions with small ionic radii (typically Na or Li ions) in the glass plate are replaced by metal ions with large ionic radii (typically K ions for Na ions, and both Na and K ions for Li ions).

[0180] Chemical strengthening treatment, i.e., ion exchange treatment, can be performed, for example, by immersing the glass plate in a molten salt such as potassium nitrate heated to 360°C to 600°C for 0.1 hours to 500 hours. It should be noted that the heating temperature of the molten salt is preferably 375°C or higher, and more preferably 500°C or lower. The immersion time of the glass plate in the molten salt is preferably 0.3 hours or higher, and more preferably 200 hours or lower.

[0181] Molten salts used for chemical fortification treatment can include nitrates, sulfates, carbonates, and chlorides. Examples of nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Examples of sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Examples of carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Examples of chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts can be used alone or in combination.

[0182] In this embodiment, the processing conditions for chemical strengthening can be selected by taking into account the characteristics and composition of the glass, the type of molten salt, and the desired chemical strengthening properties such as the surface compressive stress and the depth of the compressive stress layer of the final chemically strengthened glass.

[0183] Furthermore, in this embodiment, chemical strengthening treatment can be performed only once, or multiple chemical strengthening treatments can be performed under two or more different conditions (multi-step strengthening). Here, for example, as the first step of chemical strengthening treatment, chemical strengthening treatment is performed under the condition of large DOL and relatively small CS. Then, as the second step of chemical strengthening treatment, when chemical strengthening treatment is performed under the condition of small DOL and relatively high CS, the CS of the outermost surface of the chemically strengthened glass can be increased, while the internal tensile stress area (St) can be suppressed, and the internal tensile stress (CT) can be suppressed to a low level.

[0184] The chemically strengthened glass preferably has a layer containing a fluorinated organic compound on at least a portion of its surface. By providing this fluorinated organic compound layer, stain resistance and finger slip resistance can be improved. Examples of fluorinated organic compounds include silane compounds containing perfluoro(poly)ether groups. Furthermore, the thickness of the aforementioned organic compound layer is preferably 0.1 nm or more, and more preferably 1000 nm or less.

[0185] When the glass is a plate-shaped glass sheet, from the viewpoint of improving the chemical strengthening effect, its sheet thickness (t) is, for example, 2 mm or less, preferably 1.5 mm or less, more preferably 1 mm or less, further preferably 0.9 mm or less, particularly preferably 0.8 mm or less, and most preferably 0.7 mm or less. Furthermore, from the viewpoint of obtaining a sufficient strength improvement effect from the chemical strengthening treatment, the sheet thickness is, for example, 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.4 mm or more, and further preferably 0.5 mm or more.

[0186] The shape of this glass can be other than a sheet, depending on the product and application. Furthermore, the glass sheet can also have a frame with varying thicknesses around its perimeter. The shape of the glass sheet is not limited to these; for example, the two main surfaces may not be parallel, and one or both of the main surfaces may be curved. More specifically, the glass sheet can be, for example, a flat sheet without warping, or a curved glass sheet with a curved surface.

[0187] This glass, and chemically strengthened glass, is useful as protective glass, for example. It is particularly useful as protective glass for mobile devices such as mobile phones, smartphones, portable information terminals (PDAs), and tablets. Furthermore, it is useful as protective glass for display devices not intended for portability, such as televisions (TVs), personal computers (PCs), and touch panels; as building materials such as elevator walls, building walls (full-screen displays) and window glass; as desktops; as interior trim for automobiles or aircraft; and as housings with non-plate-like curved shapes achieved through bending and forming.

[0188] Example

[0189] The present invention will be described below through examples, but the invention is not limited thereto. G1 to G44 and G49 to G66 are examples, and G45 to G48 are comparative examples. In addition, S1 to S7, S9 to S14 and S17 to S22 are examples, and S8, S15 and S16 are comparative examples. It should be noted that for each measurement result in the table, "-" indicates that it was not evaluated.

[0190] (The manufacture of chemically strengthened glass)

[0191] Glass sheets were produced by melting the glass according to the molar percentages of oxides shown in Tables 1 to 5 using a platinum crucible. Commonly used glass raw materials, such as oxides, hydroxides, carbonates, or nitrates, were appropriately selected and weighed to obtain 1000g of glass. The mixed raw materials were then placed in a platinum crucible and melted in a resistance-heated electric furnace at 1500°C–1700°C for approximately 3 hours to degas and homogenize. The resulting molten glass was poured into a mold and held at the glass transition temperature +50°C for 1 hour, then cooled to room temperature at a rate of 0.5°C / min to obtain a glass block. The glass block was cut, ground, and finally mirror-finished on both sides to produce a sheet glass with dimensions of 50mm x 50mm x 0.7mm, thus obtaining chemically strengthened glass.

[0192] The physical properties of the obtained chemically strengthened glass were evaluated as follows. The results are shown in Tables 1 to 5. In Tables 1 to 5, the values ​​in bold and italics are estimates calculated from the glass composition.

[0193] <Entropy Function>

[0194] The entropy function S was calculated using the contents of Li₂O, Na₂O, and K₂O.

[0195] <Density>

[0196] The density is calculated from the value determined by weighing in liquid (JIS Z8807:2012 Method for Determination of Density and Specific Gravity of Solids) and the glass composition. The unit is g / cm³. 3 In the table, it is represented by "d".

[0197] Young's Modulus

[0198] The Young's modulus (E) (unit: GPa) of glass before chemical strengthening was determined using the ultrasonic pulse method (JIS R 162:1995).

[0199] <Average linear thermal expansion coefficient α and glass transition temperature (Tg)>

[0200] The average linear expansion coefficient (α) at ​​temperatures ranging from 50℃ to 350℃ 50-350 (Unit: 10) -7 The glass transition temperature (Tg) and the glass transition temperature (Tg) were calculated from the values ​​determined according to JIS R3102:1995 "Test method for mean linear expansion coefficient of glass" and the glass composition. They are represented by "α" and "Tg" in the table, respectively.

[0201] <T2, T4>

[0202] For glass before chemical strengthening, the viscosity is measured to be 10 using a rotational viscometer (according to ASTM C 965-96). 2 Temperature T2 and viscosity reach 10 dPa·s 4 The temperature T4 at dPa·s is calculated from the measured value and the glass composition. The values ​​are then expressed using the "Tlog" formula in the table. 10 η = 2, Tlog 10 η = 4” indicates.

[0203] <Fracture toughness value K1c>

[0204] The fracture toughness value K1c of the glass before chemical strengthening was determined using the DC-DC method with an Autograph (Shimadzu AGS-X) and an observation camera (Acta Metall Matter, Vol. 43, pp. 3453-3458, 1995). Furthermore, the estimated value was calculated from the measured value and the glass composition.

[0205] <Devitrification growth rate>

[0206] The growth rate of crystals caused by devitrification should be determined according to the following operating procedures.

[0207] The glass slides were crushed and graded using a mortar and pestle. The glass particles that passed through a 3.35 mm sieve but not through a 2.36 mm sieve were washed with ion-exchanged water and then dried for testing.

[0208] A glass particle is placed in each of the recesses of a slender platinum pool with multiple recesses, and heated in an electric furnace at 1000°C to 1100°C until the surface of the glass particle melts and becomes smooth.

[0209] Next, the glass is placed in a temperature gradient furnace maintained at a specified temperature for heat treatment for a certain period of time (denoted as t hours), then removed to room temperature and quenched. According to this method, a slender container can be placed inside the temperature gradient furnace to simultaneously heat multiple glass particles.

[0210] The heat-treated glass was observed using a polarizing microscope (Nikon ECLIPSE LV100ND), and the diameter of the largest crystal observed was measured (denoted as L μm). Observations were conducted under conditions of 10x eyepiece, 5x to 100x objective lens, transmitted light, and polarized light. Since the crystal growth due to devitrification can be considered isotropic, the devitrification (crystal) growth rate is L / (2t) [unit: μm / hour].

[0211] The measured crystals were those that did not precipitate from the interface with the container. This is because devitrification growth at the metal interface tends to differ from the typical devitrification growth behavior that occurs inside the glass or at the glass-atmosphere interface.

[0212] <Liquid phase temperature>

[0213] The pulverized glass particles were placed in a platinum dish and heat-treated in an electric furnace at a constant temperature for 17 hours. The heat-treated glass was observed using a polarizing microscope, and the devitrification temperature was estimated using a method for evaluating the presence or absence of devitrification. For example, if the table states "1325-1350", it means that devitrification occurred when heat-treated at 1325°C, but not when heat-treated at 1350°C. In this case, the devitrification temperature is greater than or equal to 1325°C and less than 1350°C.

[0214] <Surface resistivity>

[0215] (Substrate cleaning)

[0216] The glass substrate was cleaned for 5 minutes with an alkaline cleaning agent obtained by mixing 4% sodium metasilicate nonahydrate, 20% polyethylene oxide alkyl ether and pure water. Then it was cleaned for 5 minutes with a neutral detergent, and then cleaned for 5 minutes each with pure water at room temperature, 50°C and 65°C. Finally, the substrate surface was dried by blowing hot air at 65°C for 6 minutes.

[0217] (Preparation for Measurement)

[0218] A 30 nm Pt film was formed on the surface of a glass substrate (50 mm × 50 mm) using a magnetron sputtering coating machine (Quorum Techbiologies, Q300TT) under an Ar atmosphere. Figure 5 The comb-shaped electrode pattern shown. Figure 5 In the text, the unit for the length of each width is mm.

[0219] (Measurement)

[0220] Measurements were performed using a digital ultra-high resistance / micro-current meter (ADVANTEST R830A ULTRA HIGH RESISTANCEMETER).

[0221] A glass plate was placed on a copper substrate, and copper wires were connected to the resulting electrodes. The substrate was then heated to 50°C and allowed to stand for 30 minutes until the temperature stabilized. After the temperature stabilized, a voltage of 50V was applied, and the substrate was left to stand for 3 minutes until the voltage stabilized. The current was then measured, and the current value was read after 3 minutes. The surface resistivity (Ω / □) was calculated using the above formula. The logarithm of the surface resistivity is recorded in the table.

[0222] Frequency hopping

[0223] The ring with an inner diameter of 38 mm, an outer diameter of 40 mm, and a width of 1 mm is formed by sputtering onto the surface of a glass substrate (50 mm × 50 mm × 0.7 mm). Figure 6 The electrode pattern shown was used to determine the complex admittance using an impedance analyzer (Keysight Technologies, Precision LCR meter E4980A and 16451B dielectric test fixture, auxiliary electrode A). The frequency hopping (Hz) was calculated using the complex admittance value obtained by Almond-West fitting.

[0224] In this embodiment, K, n1, n2, C ∞ Assuming the thickness of the glass plate is essentially constant, we set K = -11.214, n1 = 0.995, n2 = 0.576, and C... ∞ =20.726. The frequency hopping ωp is calculated based on the Almond-West equation and the obtained complex admittance. The logarithm of the frequency hopping ωp is recorded in the table.

[0225] <Antifouling layer peel resistance>

[0226] To form an antifouling layer on the surface of a glass plate (5cm×5cm), follow these steps: perform rubber friction abrasion, and then measure the water contact angle.

[0227] (Formation of the antifouling layer)

[0228] The glass plate, after being washed with water, underwent further plasma cleaning, followed by the deposition of a fluorine-containing organic compound (manufactured by Daikin Industries, UD-509) using a vacuum evaporation method with resistance heating. The pressure inside the vacuum chamber during film deposition was set to 3.0 × 10⁻⁶. -3 Pa, vapor deposition output is 318.5 kA / m 2 The vapor deposition process lasted 300 seconds. The resulting antifouling layer had a thickness of 15 nm.

[0229] (Rubber friction and wear test)

[0230] Using a surface abrasion tester (3-piece type) (manufactured by Daiei Scientific Instruments Co., Ltd., device name: PA-300A), the surface abrasion was rubbed 7500 times with a 6mm diameter rubber (manufactured by WOOJIN Co., Ltd., Pink Pencil) under the conditions of 1kgf load, 40mm stroke width, 40rpm speed, 25℃, and 50%RH. Then, the water contact angle of the antifouling layer surface was measured.

[0231] (Water contact angle measurement)

[0232] Add approximately 1 μL of pure water to the surface of the antifouling layer and measure the water contact angle (°) using a contact angle meter.

[0233] <β-OH>

[0234] As an indicator of the moisture content of glass before chemical strengthening, the value of β-OH was determined using an FT-IR spectrophotometer (Nicolet iS10, manufactured by Thermo Fisher Scientific).

[0235] Table 1

[0236]

[0237] Table 2

[0238]

[0239]

[0240]

[0241]

[0242] As shown in Tables 1 to 5, the glass in the examples exhibits low surface resistivity and good devitrification characteristics even without strengthening. On the other hand, G45, as a comparative example, has a high entropy function and high surface resistivity. G46, with a high total alkali content, has a low K1c.

[0243] G47 and G48, as comparative examples of glasses with high Al2O3 content and low Na2O+K2O content, are glasses with high liquidus temperatures, fast devitrification growth rates, and poor devitrification characteristics.

[0244] <Chemical fortification properties>

[0245] A portion of the glass underwent chemical strengthening (ion exchange) treatment under the conditions shown in Tables 6 and 7. In the tables, the strengthening salt "Na50-K50" refers to a molten salt with a Na:K molar ratio of 50:50. Additionally, examples in Ion Exchange 2 indicate two-step chemical strengthening treatment, while examples in blank columns indicate only one-step chemical strengthening treatment.

[0246] The surface compressive stress (CS) and depth of compressive stress layer (DOL) of the chemically strengthened glass were measured using a surface stress meter (Orihara Manufacturing Co., Ltd., surface stress meter FSM-6000). The internal CS and DOL were measured using a diffused light photoelastic stress meter (SLP-1000). In Tables 6 and 7, "CS1" represents the compressive stress value at a depth of 50 μm from the surface, and "CS2" represents the CS of the surface layer. "D1" is the DOL measured using the diffused light photoelastic stress meter, and "D2" is the depth of compressive stress layer measured using the surface stress meter, representing the depth of potassium ion penetration. Empty columns in the tables indicate that measurements were not taken.

[0247] <Surface resistivity, frequency hopping, and peel resistance of the antifouling layer>

[0248] Surface resistivity, frequency hopping, and peel resistance of the antifouling layer were evaluated using the same methods as for the glass before chemical strengthening. The results are shown in Tables 6 and 7. Empty columns in the tables indicate that no measurements were taken.

[0249]

[0250]

[0251] S14, used as a comparative example of G44 with a low Al2O3 content, has poor chemical strengthening properties and cannot achieve the required strength.

[0252] Although the present invention has been described in detail and with reference to specific embodiments, various changes and modifications can be made without departing from the spirit and scope of the invention, which will be apparent to those skilled in the art. This application is based on Japanese Patent Application No. 2019-132124, filed on July 17, 2019, and Japanese Patent Application No. 2020-006948, filed on January 20, 2020, the contents of which are incorporated herein by reference.

[0253] Label Explanation

[0254] 1. Comb-shaped electrode

[0255] 11 First comb-shaped electrode

[0256] 12 Second comb-shaped electrode

Claims

1. A type of glass, wherein, The glass contains, in molar percentages based on oxides: 60%–72% SiO2, 12%–20% Al2O3, 5%–16% Li2O, 0%~8% Na2O, 0.1%–3% K2O, and The total amount of either Na₂O or K₂O is 2% to 15%. The ZrO2 content is less than 1%, but does not include 1%. The MgO content is below 6%. The ratio of Li2O content to the total amount of Li2O, Na2O, and K2O (P) Li Above 0.40 The combined content of MgO, CaO, SrO, BaO, and ZnO is 0%–10%. The content ratio expressed by [Al2O3] / ([Li2O]+[Na2O]+[K2O]) is 0.8 or higher, and The value of S, expressed by the following formula, is less than 0.

37. S=-P Li ×log 10 (P Li )-P Na ×log 10 (P Na )-P K ×log 10 (P K ) Here, P Li =[Li2O] / ([Li2O]+[Na2O]+[K2O]) P Na =[Na2O] / ([Li2O]+[Na2O]+[K2O]) P K =[K2O] / ([Li2O]+[Na2O]+[K2O]) Wherein, [Li2O], [Na2O], [K2O], and [Al2O3] represent the content of Li2O, Na2O, K2O, and Al2O3 respectively, expressed in mol%.

2. The glass as claimed in claim 1, wherein, The glass contains 0.1% to 5% CaO in molar percentage based on oxides.

3. The glass as described in claim 1 or 2, wherein, The glass contains 0.02% to 1% TiO2 in molar percentage based on oxides.

4. The glass as claimed in claim 1 or 2, wherein, The fracture toughness value K1c of the glass is 0.70 MPa. m 1 / 2 above.

5. The glass as claimed in claim 1 or 2, wherein, The total content of MgO and CaO in the glass is 0.1% to 3% based on the molar percentage of oxides.

6. The glass as claimed in claim 1 or 2, wherein, The total content of SrO, BaO and ZnO in the glass is less than 1.5% based on the molar percentage of oxides.

7. The glass as claimed in claim 1 or 2, wherein, The total content of MgO, CaO, SrO, BaO and ZnO in the glass is less than 1% based on the molar percentage of oxides.

8. The glass as claimed in claim 1 or 2, wherein, The K2O content in the glass is less than 1% based on the molar percentage of oxides.

9. The glass as claimed in claim 1 or 2, wherein, The surface resistivity of the glass at 50°C is 10. 13 Below Ω / □.

10. The glass as claimed in claim 1 or 2, wherein, The viscosity of the glass reaches 10. 2 dPa The temperature (T2) at time s is below 1700℃.

11. A chemically strengthened glass, wherein, The surface compressive stress value of the chemically strengthened glass is above 600 MPa. The matrix glass composition of the chemically strengthened glass, based on oxides as a molar percentage, contains: 60%–72% SiO2, 12%–20% Al2O3, 5%–16% Li2O, 0%~8% Na2O, 0.1%–3% K2O, and The total amount of either Na₂O or K₂O is 2% to 15%. The ratio of Li2O content to the total amount of Li2O, Na2O, and K2O (P) Li Above 0.40 The combined content of MgO, CaO, SrO, BaO, and ZnO is 0%–10%. The content ratio expressed by [Al2O3] / ([Li2O]+[Na2O]+[K2O]) is 0.8 or higher, and The chemically strengthened glass has a matrix glass composition with an S value of 0.37 or less, as expressed by the following formula. S=-P Li ×log 10 (P Li )-P Na ×log 10 (P Na )-P K ×log 10 (P K ) Here, P Li =[Li2O] / ([Li2O]+[Na2O]+[K2O]) P Na =[Na2O] / ([Li2O]+[Na2O]+[K2O]) P K =[K2O] / ([Li2O]+[Na2O]+[K2O]) Wherein, [Li2O], [Na2O], [K2O], and [Al2O3] represent the content of Li2O, Na2O, K2O, and Al2O3 respectively, expressed in mol% terms. The frequency hopping of the chemically strengthened glass is 10. 2.8 Hz and above.

12. The chemically strengthened glass according to claim 11, wherein, The chemically strengthened glass contains 0.1% to 5% CaO in molar percentages based on oxides.

13. The chemically strengthened glass as described in claim 11 or 12, wherein, The chemically strengthened glass contains 0.02% to 1% TiO2 in molar percentage based on oxides.

14. The chemically strengthened glass as described in claim 11 or 12, wherein, The chemically strengthened glass has a surface resistivity of 10⁻⁶ at 50°C. 15 Below Ω / □.

15. The chemically strengthened glass as described in claim 11 or 12, wherein, A layer containing a fluorine-containing organic compound is formed on at least a portion of the surface of the chemically strengthened glass.

16. A protective glass, wherein, The protective glass comprises the chemically strengthened glass according to any one of claims 11 to 15.

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