Method for manufacturing glass articles, glass articles and laminates

Abstract

To provide a glass article having high pendrop strength.SOLUTION: A method for producing a glass article comprises: a preparation step S1 in which an alkali aluminosilicate glass having a glass composition containing an alkali metal oxide is prepared as a glass to be treated; and a water treatment step S3 in which the glass to be treated is kept in contact with treatment water for a duration equal to or longer than 0.5 hours but shorter than 15 hours.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a glass article, a glass article, and a laminate including the glass article.

Background Art

[0002] As cover glass for devices such as various electronic terminals and display devices, chemically strengthened glass is often used. Among these types of devices, so-called foldable types that enable the display surface of the display to be folded have also been developed, and chemically strengthened glass may also be used for the cover glass of such foldable devices.

[0003] Chemically strengthened glass has a compressive stress layer formed by ion exchange treatment on the surface, thereby suppressing the formation and propagation of cracks on the surface and obtaining high strength. It is considered that the strength of the strengthened glass can be improved by adjusting the formation mode of such a compressive stress layer (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in glass articles used for cover glass and the like, there is still room for improvement in obtaining higher impact resistance. In particular, in the case of a device corresponding to pen input using a stylus pen, local impact is likely to be applied to the glass article. Therefore, there is a demand for the development of a glass article having a high pen drop strength that can sufficiently withstand such pen input.

[0006] The object of this invention is to provide a glass article having high pendrop strength. [Means for solving the problem]

[0007] (1) The present invention, which was devised to solve the above problems, is characterized by comprising a preparation step of preparing a treatment glass made of alkali aluminosilicate glass containing alkali metal oxide as the glass composition, and a water treatment step of contacting the treatment glass with treatment water for 0.5 hours or more and less than 15 hours.

[0008] As a result of diligent research, the inventors have found that when the glass to be treated is alkali aluminosilicate glass, the pendrop strength of the treated glass is significantly improved by performing a water treatment process in which the treated glass is in contact with treated water for the predetermined time described above. Furthermore, this effect of improving pendrop strength persists even after the water treatment process, that is, after the contact between the treated glass and the treated water is released. Therefore, it is possible to provide glass articles with high pendrop strength.

[0009] (2) In the configuration of (1) above, it is preferable to immerse the glass to be treated in treated water at 46 to 100°C during the water treatment process.

[0010] By increasing the temperature of the treated water in this way, the pendrop strength of the treated glass can be efficiently improved in a short time. In other words, the processing time (contact time between the treated glass and the treated water) required to obtain the desired pendrop strength can be relatively shortened. Therefore, glass articles with high pendrop strength can be manufactured efficiently.

[0011] (3) In the configuration of (1) above, in the water treatment process, the glass for treatment may be immersed in treated water heated to 100°C or higher under a pressurized atmosphere.

[0012] By increasing the temperature of the treated water in this way, the pendrop strength of the glass being treated can be improved efficiently in a short time. In other words, the processing time required to obtain the desired pendrop strength can be relatively shortened. Therefore, glass articles with high pendrop strength can be manufactured efficiently.

[0013] (4) In any of the configurations described in (1) to (3) above, it is preferable that the electrical conductivity of the treated water is 3 mS / m or less in the water treatment process.

[0014] By using treated water with low electrical conductivity in this way, the pendrop strength of the treated glass can be further improved. Consequently, the pendrop strength of glass articles manufactured from this treated glass will also be further improved.

[0015] (5) In any of the configurations (1) to (4) above, the glass to be processed is preferably in the form of a plate or sheet with a thickness of 0.005 to 0.1 mm.

[0016] As the processing glass becomes thinner in this way, the glass articles manufactured from this processing glass can be suitably used in foldable type devices. On the other hand, the impact resistance of the glass articles inevitably tends to decrease, making the improvement of pen drop strength even more important. Therefore, the pen drop strength improvement effect of the present invention becomes more useful.

[0017] (6) In the configuration of (5) above, a thinning step may be further provided before the water treatment step, in which the glass to be treated is thinned to within the above thickness range (0.005 to 0.1 mm) by etching.

[0018] (7) In the configuration of (5) above, the glass for processing may be pre-formed within the above thickness range (0.005 to 0.1 mm) by the overflow downdraw method.

[0019] (8) In any of the configurations of (1) to (7) above, it is preferable to further include a chemical strengthening step of bringing the glass for treatment into contact with an alkali metal nitrate before the water treatment step to form a compressive stress layer having a maximum compressive stress of 100 MPa or more on the surface.

[0020] In this way, the glass for treatment and the glass article become chemically strengthened glass having a compressive stress layer on the surface. Therefore, while improving the pendulum drop strength of the glass article, the bending strength can also be improved. For a glass article with such improved bending strength, it can also be suitably used for a foldable type device.

[0021] (9) In the configuration of (8) above, in the water treatment step, it is preferable that the temperature of the treatment water is 50 to 95 °C, and the contact time between the glass for treatment and the treatment water is 0.5 to 10 hours.

[0022] In this way, it becomes water treatment conditions particularly suitable when the glass for treatment is chemically strengthened glass, and the pendulum drop strength of the glass article made of chemically strengthened glass can be efficiently improved.

[0023] (10) In the configuration of (8) or (9) above, the glass for treatment, as a glass composition, contains, in mol%, 50 to 80% of SiO2, 5 to 25% of Al2O3, 0 to 35% of B2O3, 0 to 20% of Li2O, 1 to 20% of Na2O, and 0 to 10% of K2O. In the chemical strengthening step, it is preferable that the alkali metal nitrate is a molten salt containing potassium nitrate.

[0024] In this way, even when the glass for treatment is thin, it becomes easier to improve both the pendulum drop strength and the bending strength of the glass article.

[0025] (11) In any of the configurations of (8) to (10) above, it is preferable to further include a surface etching step of etching the glass for treatment in a range shallower than the compressive stress layer after the ion exchange step and before the water treatment step.

[0026] By doing so, in the ion exchange process or the like, surface defects formed on the glass for treatment can be reduced, so that the pendulum drop strength and / or bending strength of the glass article can be improved.

[0027] (12) The glass article according to the present invention devised to solve the above problems is a plate-like or sheet-like glass article having a thickness of 0.005 to 0.1 mm, and in a pendulum drop test in which a 5.7 g ballpoint pen having a spherical tip with a diameter of 0.7 mm is dropped onto the main surface, it is characterized in that the 60% fracture height is 5 cm or more.

[0028] By doing so, a glass article having a high pendulum drop strength that can sufficiently withstand pen input can be obtained.

[0029] (13) In the configuration of (12) above, it is preferable to provide a compressive stress layer having a maximum compressive stress of 100 MPa or more on the surface.

[0030] By doing so, in addition to the pendulum drop strength, the bending strength is also improved, so that it can be suitably used for a foldable type device.

[0031] (14) The laminate according to the present invention devised to solve the above problems includes a glass article having the configuration of (12) or (13) above, and a protective layer or a reinforcing layer laminated on at least one main surface of the glass article.

[0032] By doing so, the glass article can be protected by the protective layer to achieve a higher pendulum drop strength, or the glass article can be reinforced by the reinforcing layer to achieve a higher bending strength.

Effect of the Invention

[0033] According to the present invention, a glass article having a high pendulum drop strength can be provided.

Brief Description of the Drawings

[0034] [Figure 1] This is a schematic diagram showing a cross-section of a glass article according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating the stress distribution in the thickness direction of a glass article according to the first embodiment of the present invention. [Figure 3] This is a flowchart of a method for manufacturing a glass article according to the first embodiment of the present invention. [Figure 4] This is a cross-sectional view showing an embodiment of a water treatment step included in the manufacturing method of a glass article according to the first embodiment of the present invention. [Figure 5] This is a schematic diagram showing a cross-section of a laminate according to a second embodiment of the present invention. [Figure 6] This is a flowchart of a method for manufacturing a glass article according to the third embodiment of the present invention. [Figure 7] This is a flowchart of a method for manufacturing a glass article according to the fourth embodiment of the present invention. [Figure 8] This is a flowchart of a method for manufacturing a glass article according to the fifth embodiment of the present invention. [Figure 9] This is a side view showing an embodiment of the pendrop test. [Figure 10] This is a side view showing an embodiment of a bending fracture test. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, corresponding components will be denoted by the same reference numerals, and redundant explanations may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other embodiments described earlier can be applied to the other parts of that configuration. Furthermore, not only the combinations of configurations explicitly stated in the description of each embodiment, but also the configurations of multiple embodiments can be partially combined even if not explicitly stated, as long as there are no particular problems with the combination.

[0036] (First Embodiment) <Glassware> As shown in Figure 1, the glass article 1 according to the first embodiment is in the form of a plate or a sheet. The thickness t of the glass article 1 is not particularly limited, but is preferably 0.005 to 0.1 mm. The present invention is particularly useful for such thin glass.

[0037] In a pen drop test in which a 5.7g pen with a spherical tip having a diameter of 0.7mm is dropped onto the main surface, the glass article 1 preferably has a 60% break height of 5cm or more. More preferably, the 60% break height of the glass article 1 is 7cm or more, 10cm or more, or 15cm or more.

[0038] In this embodiment, the glass article 1 is a chemically strengthened glass that has been chemically strengthened by ion exchange, and comprises a compressive stress layer 2 and a tensile stress layer 3. This makes it possible to improve not only the pendrop strength but also the bending strength.

[0039] If the glass article 1 is chemically strengthened glass, the two-point bending strength of the glass article 1 is preferably 900 MPa or more. More preferably, the two-point bending strength of the glass article 1 is 1000 MPa or more, 1100 MPa or more, or 1200 MPa or more.

[0040] The compressive stress layer 2 is formed in the surface layer of the glass article 1, including the main surface 1a and the end surface 1b. The tensile stress layer 3 is formed inside the glass article 1, i.e., at a deeper position than the compressive stress layer 2. Here, the main surface refers to the front and back surfaces of the entire plate-like or sheet-like glass surface, excluding the end surface.

[0041] An example of the stress distribution of glass article 1 is shown in Figure 2. In Figure 2, the vertical axis represents the stress value, and the horizontal axis represents the depth from the surface. Although Figure 2 is a schematic representation of the stress distribution using linear approximation, the stress distribution can be approximated by other functions (e.g., a single curved function or a combination of multiple curved functions). Furthermore, unless otherwise specified in this specification, the magnitude of each stress is given as an absolute value. The stress distribution of glass article 1 is not limited to the embodiment shown in Figure 2.

[0042] The stress distribution shown in Figure 2 illustrates the case where the glass article 1 is tempered glass that has undergone a single-step ion exchange treatment. In the stress distribution of glass article 1, the compressive stress is maximum at the surface (maximum compressive stress CS), and the stress gradually decreases as the depth from the surface increases, becoming zero at depth DOC. That is, DOC is synonymous with the depth of the compressive stress. A tensile stress layer 3 with tensile stress extends in the region deeper than depth DOC. The stress distribution of glass article 1 is preferably symmetrical on the front and back sides, as shown in Figure 2.

[0043] The tensile stress layer 3 comprises a first region A1 in which the tensile stress fluctuates in the thickness direction of the glass article 1, and a second region A2 in which the tensile stress is constant in the thickness direction. More specifically, the first region A1 extends from the depth DOC of the compressive stress layer 2 to the tensile stress convergence depth DCT, and is a region in which the absolute value of the tensile stress gradually increases (decreases in the negative number notation shown in Figure 2) as the depth increases. The second region A2 extends to a region deeper than the tensile stress convergence depth DCT, and is a region in which the tensile stress is constant in the thickness direction. Note that "constant tensile stress" means that the amount of change in stress in the depth direction is 0.5 MPa / μm or less, and this amount of change can be calculated, for example, by the differential value of the stress sampled at 0.1 μm intervals.

[0044] The depth DOC of the compressive stress layer 2 of the glass article 1 is preferably 20 μm or less, 1 μm to 19 μm, 2 μm to 18 μm, 3 μm to 17.5 μm, or 4 μm to 17 μm. The inventors conducted various studies on the compressive stress value of the surface and the threshold depth of the compressive stress layer to prevent dangerous fracture conditions. As a result, they found that for thin glass of 0.1 mm or less, setting the depth of the compressive stress layer to 20 μm or less is effective. This ensures sufficient strength against bending while also guaranteeing safety.

[0045] The maximum compressive stress CS in the compressive stress layer 2 of the glass article 1 is preferably 100 MPa or more, 200 MPa to 1000 MPa, 300 MPa to 900 MPa, 400 MPa to 870 MPa, 430 MPa to 850 MPa, or 450 MPa to 800 MPa. By setting CS within these ranges, high bending strength can be obtained.

[0046] The depth DOC of the compressive stress layer 2 satisfies the thickness t of the glass article 1 and the following equation (2). DOC / t ≤ 0.25 (2) By limiting the ratio of DOC to t within the above range, sufficient strength against bending can be achieved while ensuring safety. The upper limit of DOC / t is preferably 0.23 or less. The lower limit of DOC / t is preferably 0.03 or more and 0.10 or more.

[0047] The tensile stress convergence depth (DCT) can be calculated by the following equation (3) when the tensile stress is obtained. DCT = (CS + CT) / (CS / DOC) (3)

[0048] The upper limit range for the maximum tensile stress CT in the second region A2 is preferably 1000 MPa or less, 500 MPa or less, 400 MPa or less, 285 MPa or less, 250 MPa or less, 240 MPa or less, 230 MPa or less, 220 MPa or less, 210 MPa or less, 200 MPa or less, 190 MPa or less, 180 MPa or less, 170 MPa or less, 160 MPa or less, 150 MPa or less, 145 MPa or less, 140 MPa or less, 130 MPa or less, 120 MPa or less, 110 MPa or less, 100 MPa or less, 95 MPa or less, 85 MPa or less, and 70 MPa or less. The lower limit range for the maximum tensile stress CT is preferably 10 MPa or more, 20 MPa or more, 35 MPa or more, 50 MPa or more, 55 MPa or more, and 60 MPa or more. By limiting CT as described above, it is possible to ensure strength against bending while ensuring safety that prevents dangerous failure patterns during fracture.

[0049] Furthermore, stress values ​​such as CS, DOC, DCT, and CT can be derived by measuring the stress distribution of the glass using measuring devices such as the FSM-6000 or SLP-1000 manufactured by Orihara Seisakusho.

[0050] The lower limit of the Young's modulus of glass article 1 is preferably 55 GPa or higher, 57 GPa or higher, 60 GPa or higher, or 62 GPa or higher. The upper limit of the Young's modulus of glass article 1 is preferably 90 GPa or lower.

[0051] As a method for forming glass article 1 into a sheet, the overflow downdraw method is preferred from the viewpoint of cost and production volume. However, the thinner the sheet, the more rapidly the glass is cooled, and the lower the CS and the deeper the DOC tend to be. Furthermore, when ion exchanging thin glass, it is known that it is more difficult to obtain a high CS compared to thick glass because there is less internal glass to suppress the volume expansion of the ion exchange portion. Therefore, achieving both a high CS and a shallow DOC at a high level for thin glass is not easy and goes beyond mere design considerations. In other words, it is necessary to appropriately select the glass composition, the glass forming method, and the strengthening conditions. Accordingly, alkali aluminosilicate glass, which is suitable for chemical strengthening, is suitable for glass article 1, and among alkali aluminosilicate glass, a composition that can obtain a particularly high surface compressive stress value is suitable. Furthermore, a compositional balance that achieves a high liquid-phase viscosity in order to enable forming by the overflow downdraw method is preferable.

[0052] Glass article 1 preferably contains, for example, SiO2 50-80%, Al2O 35-25%, B2O 30-35%, Li2O 0-20%, Na2O 1-20%, and K2O 0-10% in molar percentages as its glass composition.

[0053] SiO2 is a component that forms the network of glass. If the SiO2 content is too low, vitrification becomes difficult, and the coefficient of thermal expansion becomes too high, easily reducing thermal shock resistance. Therefore, the preferred lower limit range for SiO2 is 50% or more, 55% or more, 57% or more, 59% or more, and especially 61% or more in mole percent. On the other hand, if the SiO2 content is too high, meltability and moldability tend to decrease, and the coefficient of thermal expansion becomes too low, making it difficult to match the coefficient of thermal expansion of the surrounding material. Therefore, the preferred upper limit range for SiO2 is 80% or less, 70% or less, 68% or less, 66% or less, 65% or less, and especially 64.5% or less.

[0054] Al2O3 is a component that enhances ion exchange performance, as well as increasing strain point, Young's modulus, fracture toughness, and Vickers hardness. Therefore, the preferred lower limit range for Al2O3 is 5% or more, 8% or more, 10% or more, 11% or more, and 11.2% or more in mole percent. On the other hand, if the Al2O3 content is too high, the high-temperature viscosity increases, and meltability and moldability tend to decrease. Also, devitrified crystals tend to precipitate in the glass, making it difficult to form into a plate using methods such as the overflow downdraw method. In particular, when forming a glass plate using the overflow downdraw method with an alumina-based refractory as the refractory material of the molded body, devitrified spinel crystals tend to precipitate at the interface with the alumina-based refractory. Furthermore, acid resistance also decreases, making it difficult to apply to acid treatment processes. Therefore, the preferred upper limits for Al2O3 are 25% or less, 21% or less, 20.5% or less, 20% or less, 19.9% ​​or less, 19.5% or less, 19.0% or less, and especially 18.9% or less. By keeping the Al2O3 content, which has a significant impact on ion exchange performance, within a suitable range, it becomes easier to design thin glass to have high CS / DOC values.

[0055] B2O3 is a component that reduces high-temperature viscosity and density, stabilizes the glass, makes crystal precipitation difficult, and lowers the liquidus temperature. It also suppresses Young's modulus and increases bending strength and crack resistance. However, if the B2O3 content is too high, ion exchange treatment tends to cause surface discoloration called "yellowing," a decrease in water resistance, and a decrease in the compressive stress value of the compressive stress layer. Therefore, the preferred lower limit range for B2O3 is 0% or more, 0.01% or more, 0.02% or more, 0.1% or more, and 0.3% or more in mole percent, and the preferred upper limit range is 35% or less, 30% or less, 25% or less, 22% or less, 20% or less, and especially 15% or less. Furthermore, from the viewpoint of prioritizing a high CS, the B2O3 content can be more preferably 0.2-5% or 0.3-1%. Furthermore, from the viewpoint of improving chemical durability for the purpose of suppressing defects during etching, the upper limit of the B2O3 content can preferably be 1% or more, 1.5% or more, or 2% or more, and the lower limit can be 5% or less, 4.5% or less, 4% or less, or 3% or less. On the other hand, from the viewpoint of prioritizing the suppression of Young's modulus, the B2O3 content can more preferably be 10-25%, 15-23%, or 18-22%.

[0056] Li2O is an ion exchange component, and in particular, it is a component that exchanges Li ions contained in the glass with K ions in the molten salt to obtain a high surface compressive stress value. In addition, Li2O is a component that reduces high-temperature viscosity and improves meltability and moldability. Therefore, the preferred lower limit range for Li2O is 0% or more, 3% or more, 4% or more, 4.2% or more, 5% or more, 5.5% or more, 6.5% or more, 7% or more, 7.3% or more, 7.5% or more, 7.8% or more, and especially 8% or more. Therefore, the preferred upper limit range for Li2O is 20% or less, 15% or less, 13% or less, 12% or less, 11.5% or less, 11% or less, 10.5% or less, less than 10%, especially 9.9% or less, 9% or less, and 8.9% or less.

[0057] Na2O is an ion exchange component and also a component that reduces high-temperature viscosity, thereby improving melting and moldability. Furthermore, Na2O is a component that improves devitrification resistance and devitrification in reaction with molded refractories, especially alumina refractories. If the Na2O content is too low, melting will decrease, the coefficient of thermal expansion will decrease too much, and the ion exchange rate will tend to decrease. Therefore, the suitable lower limit range for Na2O is 1% or more, 5% or more, 7% or more, 8% or more, 8.5% or more, 9% or more, 9.5% or more, 10% or more, 11% or more, 12% or more, and especially 12.5% ​​or more in mole percent. On the other hand, if the Na2O content is too high, the phase separation viscosity tends to decrease. It may also decrease acid resistance, disrupt the balance of components in the glass composition, and conversely, decrease devitrification resistance. Therefore, the preferred upper limits for Na2O are 20% or less, 19.5% or less, 19% or less, 18% or less, 17% or less, 16.5% or less, 16% or less, 15.5% or less, and especially 15% or less.

[0058] K2O is a component that reduces high-temperature viscosity, thereby improving meltability and moldability. It also improves devitrification resistance and increases Vickers hardness. However, if the K2O content is too high, the phase separation viscosity tends to decrease. Furthermore, acid resistance decreases, the balance of components in the glass composition is disrupted, and devitrification resistance tends to decrease. Therefore, the suitable lower limit range for K2O is 0% or more, 0.01% or more, 0.02% or more, 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, 2% or more, 2.5% or more, 3% or more, and especially 3.5% or more in mole percent, and the suitable upper limit range is 10% or less, 5.5% or less, 5% or less, and especially less than 4.5%.

[0059] Li2O and Na2O are components that exchange ions with K ions in the molten salt to obtain high surface compressive stress values, and one of them is an essential component in this invention. Therefore, the preferred lower limit range for Li2O + Na2O is 1% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, 12% or more, 13% or more, 14% or more, 15% or more, 16% or more, 17% or more, 18% or more, and especially 18.5% or more in mole percent. On the other hand, if the content of Li2O + Na2O is too high, the coefficient of thermal expansion becomes too high, and the thermal shock resistance tends to decrease. Also, the balance of components in the glass composition may be disrupted, which may actually decrease the devitrification resistance. Therefore, the preferred upper limit range for Li2O + Na2O is 20% or less, and especially 19% or less.

[0060] In addition to the components listed above, glass article 1 may also contain, for example, the following components as part of its glass composition.

[0061] MgO is a component that lowers high-temperature viscosity, improves meltability and moldability, and increases strain point and Young's modulus. Among alkaline earth metal oxides, it is a component that has a significant effect on improving ion exchange performance. However, if the MgO content is too high, the density and coefficient of thermal expansion tend to increase, and the glass becomes more prone to devitrification. Therefore, the preferred upper limit range for MgO is 12% or less, 10% or less, 8% or less, 6% or less, and especially 5% or less. When introducing MgO into the glass composition, the preferred lower limit range for MgO is 0.1% or more, 0.5% or more, 1% or more, and especially 2% or more in mole percent.

[0062] Compared to other components, CaO has a significant effect in reducing high-temperature viscosity without compromising devitrification resistance, thereby improving meltability and moldability, as well as increasing strain point and Young's modulus. A CaO content of 0-10% is preferable. However, if the CaO content is too high, the density and thermal expansion coefficient will increase, and the balance of components in the glass composition will be disrupted, making the glass more prone to devitrification and reducing its ion exchange performance. Therefore, the preferred CaO content is 0-5%, 0.01-4%, 0.1-3%, and especially 1-2.5% in mole percent.

[0063] SrO is a component that reduces high-temperature viscosity without compromising devitrification resistance, thereby improving meltability and moldability, as well as increasing strain point and Young's modulus. However, if the SrO content is too high, the density and coefficient of thermal expansion increase, the ion exchange performance decreases, and the balance of components in the glass composition is disrupted, making the glass more prone to devitrification. The preferred range for SrO content is 0-5%, 0-3%, 0-1%, and especially less than 0-0.1% in mole percent.

[0064] BaO is a component that reduces high-temperature viscosity without compromising devitrification resistance, thereby improving meltability and moldability, as well as increasing strain point and Young's modulus. However, if the BaO content is too high, the density and coefficient of thermal expansion increase, the ion exchange performance decreases, and the balance of components in the glass composition is disrupted, making the glass more prone to devitrification. The preferred range for BaO content is 0-5%, 0-3%, 0-1%, and especially less than 0-0.1% in mole percent.

[0065] ZnO is a component that enhances ion exchange performance, and is particularly effective in increasing compressive stress values. It also reduces high-temperature viscosity without decreasing low-temperature viscosity. However, if the ZnO content is too high, the glass tends to split into phases, its devitrification resistance decreases, its density increases, and the stress depth of the compressive stress layer decreases. Therefore, the ZnO content is preferably 0-6%, 0-5%, 0-1%, 0-0.5%, and especially less than 0-0.1% in mole percent.

[0066] ZrO2 is a component that significantly enhances ion exchange performance and also increases viscosity and strain point near the liquid phase viscosity. However, if its content is too high, the devitrification resistance may be significantly reduced, and the density may become too high. Therefore, the preferred upper limit range for ZrO2 is 10% or less, 8% or less, 6% or less, and especially 5% or less in mole percent. Furthermore, if ion exchange performance is to be enhanced, it is preferable to introduce ZrO2 into the glass composition, in which case the preferred lower limit range for ZrO2 is 0.001% or more, 0.01% or more, 0.5%, and especially 1% or more.

[0067] P2O5 is a component that enhances ion exchange performance, and in particular, increases the stress depth of the compressive stress layer. It is also a component that suppresses the Young's modulus. However, if the P2O5 content is too high, the glass becomes more prone to phase separation. Therefore, the preferred upper limit range for P2O5 is 10% or less, 8% or less, 6% or less, 4% or less, 2% or less, 1% or less, and especially less than 0.1% in mole percent.

[0068] As a clarifying agent, one or more substances selected from the group As2O3, Sb2O3, SnO2, F, Cl, and SO3 (preferably the group SnO2, Cl, and SO3) may be introduced in an amount of 0 to 30,000 ppm (3%). From the viewpoint of effectively enjoying the clarifying effect, the content of SnO2 + SO3 + Cl is preferably 0 to 10,000 ppm, 50 to 5,000 ppm, 80 to 4,000 ppm, 100 to 3,000 ppm, and particularly 300 to 3,000 ppm. Here, "SnO2 + SO3 + Cl" refers to the total amount of SnO2, SO3, and Cl.

[0069] The preferred content range for SnO2 is 0-10000 ppm, 0-7000 ppm, and especially 50-6000 ppm. The preferred content range for Cl is 0-1500 ppm, 0-1200 ppm, 0-800 ppm, 0-500 ppm, and especially 50-300 ppm. The preferred content range for SO3 is 0-1000 ppm, 0-800 ppm, and especially 10-500 ppm.

[0070] Rare earth oxides such as Nd2O3 and La2O3 are components that increase Young's modulus, and when complementary colors are added, they can decolorize and control the color of the glass. However, the raw materials themselves are expensive, and introducing large amounts tends to reduce devitrification resistance. Therefore, the content of rare earth oxides is preferably 4% or less, 3% or less, 2% or less, 1% or less, and especially 0.5% or less.

[0071] Glass article 1 is preferably substantially free of As2O3, F, PbO, and Bi2O3 from an environmental perspective. Here, "substantially free of As2O3" means that while As2O3 is not actively added as a glass component, its presence at an impurity level is acceptable, and specifically refers to an As2O3 content of less than 500 ppm. "Substantially free of F" means that while F is not actively added as a glass component, its presence at an impurity level is acceptable, and specifically refers to an F content of less than 500 ppm. "Substantially free of PbO" means that while PbO is not actively added as a glass component, its presence at an impurity level is acceptable, and specifically refers to an PbO content of less than 500 ppm. "Substantially free of Bi2O3" means that while Bi2O3 is not actively added as a glass component, its presence at an impurity level is acceptable, and specifically refers to an Bi2O3 content of less than 500 ppm.

[0072] For example, glass article 1 may not contain B2O3 as part of its glass composition, or its B2O3 content may be limited to a very small amount. That is, glass article 1 may contain, in molar percentages, SiO2 50-80%, Al2O3 5-25%, B2O3 0-1%, Li2O 0-20%, Na2O 1-20%, and K2O 0-10%.

[0073] As another example, glass article 1 may contain B2O3 as an essential component in its glass composition. That is, glass article 1 may contain, in mole percent, SiO2 50-80%, Al2O3 5-25%, B2O3 1-5%, Li2O 0-20%, Na2O 1-20%, and K2O 0-10%.

[0074] Furthermore, if glass article 1 contains B2O3 as an essential component in its glass composition, there is a concern that the moldability of the glass may decrease. Therefore, to maintain balance, the content of other components, such as Al2O3, may be limited. In other words, glass article 1 may contain, in molar percentages, SiO2 50-80%, Al2O3 5-10%, B2O3 1-5%, Li2O 0-20%, Na2O 1-20%, and K2O 0-10%.

[0075] <Method of manufacturing glass articles> As shown in Figure 3, the method for manufacturing a glass article according to the first embodiment comprises a preparation step S1, a chemical strengthening step S2, and a water treatment step S3 in that order.

[0076] In preparation step S1, the glass that will be the basis for the glass article 1 described above (hereinafter referred to as "processing glass") is prepared. The processing glass is glass that has the same shape, dimensions, and glass composition as the glass article 1 described above.

[0077] Processing glass is obtained by cutting and processing plate-shaped or sheet-shaped mother glass, obtained by molding methods such as the overflow downdraw method, slot downdraw method, float method, or redraw method, into small pieces of glass. To obtain a smooth surface, it is preferable to use the overflow downdraw method as the molding method. Furthermore, with the overflow downdraw method, it is easy to mold processing glass with a thickness of 0.005 to 0.1 mm without polishing (including mechanical polishing and etching) after molding. When molded by the overflow downdraw method, the processing glass has a molded confluence surface inside.

[0078] The edges of the glass to be processed are preferably treated with processes such as polishing, heat treatment, or etching to chamfer or improve strength. The main surface of the glass to be processed may be polished, but if the main surface is already smooth by the overflow downdraw method, for example, or if the thickness is uniform and the glass is formed with good precision, the main surface may not be polished and can be used as an unpolished surface. If the glass is formed by the overflow downdraw method and is not polished, the main surface of the glass to be processed will be a forged surface.

[0079] In the chemical strengthening process S2, the glass to be treated is subjected to ion exchange treatment. In this embodiment, the glass to be treated is immersed in a molten salt for ion exchange treatment. By chemically strengthening the glass through ion exchange treatment in this way, the bending strength of the glass to be treated is improved.

[0080] The molten salt is a salt containing components that can be ion-exchanged with the components in the chemically strengthened glass, and is typically an alkali metal nitrate. Examples of alkali metal nitrates include NaNO3, KNO3, and LiNO3, which can be used individually (at 100% by mass) or in combination. When mixing multiple alkali metal nitrates, the mixing ratio can be arbitrarily determined, but for example, it can be 35-95% by mass of NaNO3, 5-95% of KNO3, preferably 30-80% of NaNO3, 20-70% of KNO3, and more preferably 50-70% of NaNO3, 30-50% of KNO3.

[0081] The temperature of the molten salt is, for example, 350°C to 500°C, preferably 355°C to 470°C, 360°C to 450°C, 365°C to 430°C, or 370°C to 410°C. The immersion time is, for example, 3 to 300 minutes, preferably 5 to 120 minutes or 7 to 100 minutes. Of course, the conditions such as the temperature of the molten salt and the immersion time can be appropriately changed according to the glass composition, etc., within the range in which the above stress characteristics can be obtained.

[0082] In the water treatment process S3, the glass to be treated is exposed to treated water for 0.5 hours or more but less than 15 hours. By exposing the glass to treated water in this way, the pendrop strength of the glass is improved. Furthermore, since the pendrop strength of the glass to be treated is maintained even after the water treatment process S3, the pendrop strength of the glass article 1 manufactured from the glass to be treated is also improved. Note that if the contact time between the glass to be treated and the treated water (hereinafter referred to as the water treatment time) is too short or too long, the effect of improving the pendrop strength cannot be fully realized. Therefore, it is important to keep the water treatment time within the above numerical range.

[0083] The lower limit of the water treatment time is preferably 0.75 hours or more, 1 hour or more, 1.25 hours or more, or 1.5 hours or more. The upper limit of the water treatment time is preferably 14 hours or less, 13 hours or less, 12 hours or less, or 11 hours or less.

[0084] The temperature of the treated water is, for example, 10 to 100°C. The lower limit of the treated water temperature is preferably 20°C or higher, 30°C or higher, 40°C or higher, or 46°C or higher. The upper limit of the treated water temperature is preferably 95°C or lower, 90°C or lower, or 85°C or lower. As the temperature of the treated water increases, the treatment time required to obtain the desired pendrop strength tends to decrease.

[0085] When the glass to be processed is chemically strengthened glass, it is preferable that the temperature of the treated water in the water treatment step S3 is 50 to 95°C and the water treatment time is 0.5 to 10 hours.

[0086] The electrical conductivity of the treated water is preferably 3 mS / m or less. More preferably, the electrical conductivity of the treated water is 1 mS / m or less, 0.1 mS / m or less, or 0.01 mS / m or less. As the electrical conductivity of the treated water decreases, it becomes easier to improve the pendrop strength of the treatment glass. The treated water is preferably free from detergents and their materials (e.g., surfactants, water softeners, chelating agents, pH adjusters, stabilizers), etc.

[0087] Figure 4 shows an example of an embodiment of the water treatment process S3. As shown in Figure 4, the treatment glass 6 is immersed in the treated water 5 stored in the container 4. In the treated water 5, for example, multiple pieces of treatment glass 6 are supported by support bases 7 in a vertical position at predetermined intervals in the thickness direction. The container 4 containing the treatment glass 6 and the treated water 5 is then placed in a constant temperature device (temperature control device) 8 that maintains a predetermined temperature for a predetermined time, and the treatment glass 6 is subjected to water treatment.

[0088] The method for bringing the treated water into contact with the treated glass is not particularly limited, but as described above, it is preferable to immerse the treated glass in the treated water stored in a container. In this case, it is preferable not to apply external vibrations such as ultrasound to the treated water and to leave the treated glass undisturbed in the treated water. By immersing the glass in the treated water in this way, the entire treated glass can be efficiently brought into contact with the treated water, making it easier to enjoy the effect of improving pendrop strength. The treated water may also be sprayed onto the treated glass from a nozzle or the like, or flowing water may be poured over the entire surface of the treated glass.

[0089] The glass used for processing may be moved relative to the treated water. Specifically, for example, the glass used for processing may be moved within the treated water while immersed in it, or the glass used for processing may be moved within an area where the treated water is sprayed and supplied by a nozzle or the like.

[0090] (Second embodiment) <Laminate> As shown in Figure 5, the laminate 9 according to the second embodiment comprises the glass article 1 described above, a protective layer 10a laminated on one main surface 1a (e.g., the front) of the glass article 1, and a reinforcing layer 10b laminated on the other main surface 1a (e.g., the back) of the glass article. In this way, the glass article 1 is protected by the protective layer 10a, thereby achieving higher pen drop strength. Furthermore, the reinforcing layer 10b improves the bending strength of the glass article 1, suppressing breakage when bending. Preferably, the protective layer 10a is provided on the front side of the glass article 1 that comes into contact with a pen, and the reinforcing layer 10b is provided on the back side of the glass article 1 that does not come into contact with a pen. Note that only one of the protective layer 10a and the reinforcing layer 10b may be provided.

[0091] Examples of protective layers 10a and reinforcing layers 10b include plate-shaped or sheet-shaped resins, metals, glass, etc., and these can be formed as a single layer or in combination of multiple layers. However, when the laminate 9 is applied to a foldable type device, it is preferable that the protective layer 10a and reinforcing layer 10b be resins that easily impart flexibility.

[0092] The thickness of the resin contained in the protective layer 10a and the reinforcing layer 10b is preferably 0.5 to 200 μm, 1 to 150 μm, and 2 to 100 μm, respectively. Examples of the resin material contained in the protective layer 10 include polycarbonate (PC), acrylic, polyethylene terephthalate (PET), polyether ether ketone (PEEK), polyamide (PA), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyethylene naphthalate (PEN), polyimide (PI), cycloolefin polymer (COP), epoxy, and the like.

[0093] The protective layer 10a and the reinforcing layer 10b are laminated, for example, on the main surface 1a of the glass article 1 via an adhesive layer 11. The thickness of the adhesive layer 11 is preferably 0.1 to 100 μm, 0.2 to 90 μm, or 0.3 to 80 μm. Examples of materials for the adhesive layer 11 include acrylic adhesives, silicone adhesives, rubber adhesives, UV-curable acrylic adhesives, UV-curable epoxy adhesives, thermosetting epoxy adhesives, thermosetting melamine adhesives, thermosetting phenol adhesives, ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), cycloolefin polymer (COP), etc. The protective layer 10 may also be formed directly on the main surface 1a of the glass article 1 by any method such as coating, without using the adhesive layer 11.

[0094] (Third embodiment) <Method of manufacturing glass articles> As shown in Figure 6, the method for manufacturing a glass article according to the third embodiment comprises a preparation step S11, a chemical strengthening step S12, a surface etching step S13, and a water treatment step S14, in that order. Of these, the steps other than the surface etching step S13 are the same as the corresponding steps in the embodiments described above, so a detailed explanation is omitted.

[0095] The surface etching step S13 is a process performed after the chemical strengthening step S12 and before the water treatment step S14, in which the glass to be treated is etched in a range shallower than the compressive stress layer. By performing the surface etching step S13 in this way, surface defects formed on the glass to be treated in the chemical strengthening step S12 and so on can be reduced. As a result, the pendrop strength and / or flexural strength of the glass to be treated and glass articles can be improved.

[0096] In the surface etching process S13, for example, the entire glass to be processed is immersed in a liquid etching medium, and the entire surface of the glass to be processed is wet-etched. With this process, the entire glass to be processed can be etched uniformly, so the occurrence of thickness variations caused by the etching process can be suppressed. When such an etching process is performed, the surface of the glass to be processed is composed of etched surfaces.

[0097] As the etching medium, an acidic or alkaline aqueous solution capable of etching glass can be used.

[0098] As an acidic etching medium, for example, an acidic aqueous solution containing HF can be used. When an aqueous solution containing HF is used, the etching rate on glass is high and production efficiency is good.

[0099] Aqueous solutions containing HF include, for example, aqueous solutions containing only HF, or combinations of HF and HCl, HF and HNO3, HF and H2SO4, and HF and NH4F. The concentration of each compound (HF, HCl, HNO3, H2SO4, and NH4F) is preferably 0.1 to 30 mol / L. In etching using an aqueous solution containing HF, fluorides containing glass components are generated as byproducts, which can lead to a decrease in the etching rate and defects. However, as described above, by using a mixed acid with other acids such as HCl, HNO3, or H2SO4, these byproducts can be decomposed, suppressing a decrease in productivity. When etching is performed using an acidic aqueous solution, the temperature of the acidic aqueous solution is preferably, for example, 10 to 30°C, and the immersion time of the glass to be processed is preferably, for example, 0.1 to 60 minutes.

[0100] As an alkaline etching medium, an alkaline aqueous solution containing NaOH or KOH can be used. Alkaline aqueous solutions have a relatively low etching rate for glass compared to the HF-containing etching mediums mentioned above, offering the advantage of easier and more precise control over the etching amount. They are particularly suitable when it is necessary to control the glass thickness, DOC, etc., in units of several micrometers.

[0101] In aqueous solutions containing NaOH or KOH, the concentration of the alkaline component is preferably 1 to 20 mol / L. When etching is performed using an alkaline aqueous solution, the temperature of the alkaline aqueous solution is preferably, for example, 10 to 130°C, and the immersion time of the glass to be processed is preferably, for example, 0.5 to 120 minutes. To increase productivity by increasing the etching rate, it is preferable to raise the temperature of the alkaline aqueous solution to 80°C or higher. Conversely, if it is desirable to control the etching amount with higher precision, it is preferable to limit the temperature of the alkaline aqueous solution to 70°C or lower. Furthermore, if the magnitude of the etching rate is more important, it is preferable to use an aqueous solution of NaOH.

[0102] In the surface etching process S13, the thickness of the surface layer removed from the glass to be processed is preferably 0.25 μm or more and 3 μm or less. More preferably, the thickness of the surface layer removed from the glass to be processed is 0.4 μm or more and 2.7 μm or less, 0.6 μm or more and 2.5 μm or less, or 0.8 μm or more and 2.3 μm or less. By setting the etching amount within these ranges, the variation in maximum compressive stress and compressive stress depth before and after etching can be reduced.

[0103] In glass articles manufactured through the surface etching process S13, it is preferable that the entire surface, i.e., both the front and back main surfaces and the end faces, consists entirely of etched surfaces. This reduces defects across the entire surface of the glass article, enabling high strength, particularly high pendrop strength.

[0104] (Fourth embodiment) <Method of manufacturing glass articles> As shown in Figure 7, the method for manufacturing a glass article according to the fourth embodiment comprises, in this order, a preparation step S21, a thinning step S22, a chemical strengthening step S23, a surface etching step S24, and a water treatment step S25. Of these, the steps other than the thinning step S22 are the same as the corresponding steps in the above-described embodiment, so a detailed explanation is omitted. Note that the surface etching step S24 may be omitted.

[0105] The thinning process S22 is a process in which the thickness of the glass to be processed is reduced to a range of 0.005 to 0.1 mm by etching. By performing the thinning process S22 in this way, even if a thick glass to be processed is prepared in the preparation process S21, the thickness of the glass to be processed can be reduced to an appropriate range.

[0106] In the thinning process S22, for example, the entire glass to be processed is immersed in a liquid etching medium, and the entire surface of the glass to be processed is wet-etched. The etching medium used in the surface etching process S24 can be used in the same way.

[0107] The thickness of the surface layer removed from the glass to be processed in the thinning process S22 is not particularly limited as it depends on the original thickness (initial thickness) of the glass to be processed before the thinning process S22, but it may be greater than the thickness of the surface layer removed from the glass to be processed in the surface etching process S24.

[0108] (Fifth embodiment) <Method of manufacturing glass articles> As shown in Figure 8, the method for manufacturing a glass article according to the fifth embodiment comprises a preparation step S31, a thinning step S32, and a water treatment step S33, in that order. Each step is the same as the corresponding step in the embodiments described above, but this embodiment differs in that it does not include a chemical strengthening step.

[0109] In this manufacturing method, the unstrengthened glass to be treated comes into contact with the treated water during the water treatment process S33. In this case, the pendrop strength of the glass to be treated tends to be higher than when chemically strengthened glass to be treated comes into contact with the treated water. Therefore, even glass articles manufactured through the water treatment process S33, in which unstrengthened glass to be treated comes into contact with the treated water, can obtain high pendrop strength. In other words, in this invention, the glass article is not limited to chemically strengthened glass. However, with respect to bending strength, chemically strengthened glass articles tend to have higher bending strength. Therefore, from the viewpoint of achieving both pendrop strength and bending strength, it is preferable that the glass article is made of chemically strengthened glass.

[0110] In this embodiment, the case in which a thinning step S32 is provided is illustrated, but if a glass for processing that has been pre-formed to a thickness of 0.005 to 0.1 mm can be prepared in the preparation step S31 by the overflow downdraw method or the like, the thinning step S32 does not need to be provided.

[0111] (Sixth Embodiment) <Method of manufacturing glass articles> The sixth embodiment of the method for manufacturing a glass article shows a modified version of the water treatment step in the above-described embodiment. In the above-described embodiment, the temperature of the treated water in the water treatment step is 100°C or lower, but in this embodiment, the temperature of the treated water is 100°C or higher.

[0112] One example of the water treatment process in this embodiment is immersing the glass to be treated in treated water heated to 100°C or higher under a pressurized atmosphere. Specifically, the glass to be treated is immersed in treated water stored in a container. Then, with this container placed inside a pressurizing device, the inside of the pressurizing device is pressurized and the treated water is heated to 100°C or higher. By raising the temperature of the treated water to 100°C or higher in this way, it is expected that the water treatment time required to obtain the desired pendrop strength can be shortened.

[0113] The temperature of the treated water is preferably between 100°C and 200°C. The lower limit of the treated water temperature is more preferably between 105°C and above, 110°C and above, and 120°C and above. The upper limit of the treated water temperature is more preferably between 190°C and below, 180°C and below, and 170°C and below.

[0114] The pressure of the pressurized atmosphere is preferably 0.15 to 2.0 MPa. The lower limit of the pressurized atmosphere pressure is more preferably 0.17 MPa or higher, 0.2 MPa or higher, or 0.25 MPa or higher. The upper limit of the pressurized atmosphere pressure is more preferably 1.9 MPa or lower, 1.8 MPa or lower, or 1.7 MPa or lower.

[0115] The lower limit of the water treatment time is preferably 0.6 hours or more, 0.75 hours or more, or 1 hour or more. The upper limit of the water treatment time is preferably 12 hours or less, 11 hours or less, or 10 hours or less.

[0116] Instead of immersing the glass to be treated in treatment water at 100°C or higher, the treatment water may be sprayed onto the glass as superheated steam at 100°C or higher.

[0117] Although embodiments of the present invention have been described, the embodiments of the present invention are not limited thereto, and various modifications can be made without departing from the spirit of the invention.

[0118] In the above embodiment, the shape of the glass article is not particularly limited. The shape of the glass article can be, for example, a square, rectangle, circle, ellipse, etc., when viewed from above.

[0119] In the above embodiment, the glass article may be subjected to three-dimensional bending as needed. Specifically, by pre-applying three-dimensional bending to the glass for processing, either entirely or partially, a three-dimensional curved shape can be imparted to the final manufactured glass article.

[0120] In the above embodiment, a case where a single chemical strengthening process (ion exchange treatment) is performed is illustrated, but two or three or more chemical strengthening processes may be performed. Heat treatment may also be performed before or after ion exchange. Heat treatment can relieve stress and promote ion diffusion to control the depth of the compressive stress layer, etc. When a chemical strengthening process is performed, it is preferable that the glass to be treated be washed and dried after the chemical strengthening process and before the water treatment process. When multiple chemical strengthening processes are performed as described above, the stress distribution of the strengthened glass article may have at least one of the following in the region of the compressive stress layer 2: a bending point, a maximum value, a minimum value, or an inflection point.

[0121] In the above embodiment, the tensile stress in the tensile stress layer 3 may not be constant in the thickness direction. For example, when the DOC with respect to the thickness t of the glass article is set to be relatively large (for example, when DOC ≥ 0.20t), the stress distribution in the tensile stress layer 3 can be a distribution shape that follows a downward-convex quadratic curve having a minimum value at the center of the thickness of the glass article.

[0122] In the above embodiment, the stress distribution of the glass article may be asymmetrical between the front and back sides. An asymmetrical stress distribution can be obtained by polishing one main surface of the strengthened glass article more than the other surface, or by chemically strengthening the article with a film that inhibits ion exchange applied to one main surface side. [Examples]

[0123] The following describes glass articles according to the present invention based on examples. Note that the following examples are merely illustrative, and the present invention is not limited in any way to these examples.

[0124] Samples were prepared as follows. First, treatment glass having the glass composition described in Table 1 was prepared. The Young's modulus shown in Table 1 was measured by the resonance method.

[0125] [Table 1]

[0126] Specifically, glass raw materials were mixed to have the composition shown in Table 1 and melted in a test melting furnace. The resulting molten glass was then formed into a plate or sheet using the overflow down-draw method, cut to a predetermined size, and obtained glass for processing.

[0127] Next, plate-shaped or sheet-shaped glass articles were manufactured by treating plate-shaped or sheet-shaped glass for treatment under the conditions described in Tables 2 to 8. The thinning process and surface etching process were carried out by immersing the glass for treatment in an HF aqueous solution. The chemical strengthening process was carried out by immersing the glass for treatment in a molten salt of 100% KNO3. The water treatment process was carried out by immersing the glass for treatment in treated water. In Tables 2 to 8, Nos. 1 to 29 are examples of the present invention, and Nos. 30 to 45 are comparative examples.

[0128] [Table 2]

[0129] [Table 3]

[0130] [Table 4]

[0131] [Table 5]

[0132] [Table 6]

[0133] [Table 7]

[0134] [Table 8]

[0135] <Method for manufacturing glass articles or laminates> (1) In Table 2, Nos. 1-6, the glass was subjected to a water treatment process to produce the glass articles. In Table 2, Nos. 7-8, the glass was subjected to a thinning process followed by a water treatment process in that order to produce the glass articles. In other words, in Table 2, Nos. 1-8, no chemical strengthening process was performed on the glass. Note that in Nos. 1-6, the initial thickness of the glass was the same as the thickness of the glass articles, and in Nos. 7-8, the thickness of the glass after the thinning process was the same as the thickness of the glass articles.

[0136] (2) In Table 3, for Nos. 9 to 14, the glass articles were manufactured by performing a chemical strengthening process and a water treatment process on the glass for processing in that order. In Table 3, for Nos. 15 to 16, the glass articles were manufactured by performing a thinning process, a chemical strengthening process, and a water treatment process on the glass for processing in that order. Note that in Nos. 9 to 14, the initial thickness of the glass for processing matched the thickness of the glass article, and in Nos. 15 to 16, the thickness of the glass for processing after the thinning process matched the thickness of the glass article.

[0137] (3) In Table 4, for Nos. 17 to 24, the glass articles were manufactured by performing a chemical strengthening process, a surface etching process, and a water treatment process on the glass for processing in that order. In Nos. 17 to 24, the thickness of the glass for processing after the surface etching process matches the thickness of the glass article.

[0138] (4) In Table 5, Nos. 25-26, glass articles were manufactured by performing a thinning process, a chemical strengthening process, a surface etching process, and a water treatment process on the glass for processing in that order. In Table 5, Nos. 27-29, glass articles were manufactured by performing a chemical strengthening process, a surface etching process, and a water treatment process on the glass for processing in that order. Furthermore, in Table 5, Nos. 27-29, a protective layer (PET film, PA film, PI coating) was laminated to one main surface of the glass article to produce a laminate. The PET film and PA film were bonded to the glass article via a 5 μm thick pressure-sensitive adhesive (PSA) sheet. The PI coating was formed by applying PI to the main surface of the glass article. Note that in Nos. 25-29, the thickness of the glass for processing after the surface etching process matches the thickness of the glass article.

[0139] (5) In Table 6, Nos. 30 and 31, the glass to be processed was used as a glass article without any processing. In Table 6, Nos. 32 and 33, the glass to be processed was subjected to a thinning process to manufacture the glass article. In Table 6, Nos. 34 and 35, the glass to be processed was subjected to a chemical strengthening process to manufacture the glass article. In Table 6, Nos. 36 and 37, the thinning process and chemical strengthening process were performed in that order to manufacture the glass article. In other words, in Table 6, Nos. 30 to 33, the glass to be processed was not subjected to a chemical strengthening process or a water treatment process. In Table 6, Nos. 34 to 37, the glass to be processed was not subjected to a water treatment process. Note that in Nos. 30, 31, 34 and 35, the initial thickness of the glass to be processed was the same as the thickness of the glass article. In Nos. 32, 33, 36 and 37, the thickness of the glass to be processed after the thinning process was the same as the thickness of the glass article.

[0140] (6) In Table 7, Nos. 38-39, the glass articles were manufactured by performing a chemical strengthening process and a surface etching process on the glass for processing in that order. In Table 7, Nos. 40-41, the glass articles were manufactured by performing a thinning process, a chemical strengthening process, and a surface etching process on the glass for processing in that order. In other words, in Table 7, Nos. 38-41, the water treatment process was not performed on the glass for processing. Note that in Nos. 38-41, the thickness of the glass for processing after the surface etching process matches the thickness of the glass article.

[0141] (7) In Table 8, for Nos. 42-45, the glass articles were manufactured by performing a chemical strengthening process, a surface etching process, and a water treatment process on the glass for processing in that order. In Nos. 42-45, the thickness of the glass for processing after the surface etching process matches the thickness of the glass article. In Nos. 42-45, a water treatment process is performed on the glass for processing, but the water treatment time is specified as less than 0.5 hours or 15 hours or more.

[0142] In some examples and comparative examples where a chemical strengthening process was performed, the CS, DOC, and CT of the glass articles were measured. The CS, DOC, and CT values ​​in Tables 1-8 are the values ​​measured for each glass article (sample) using the Orihara Manufacturing Co., Ltd. surface stress meter FSM-6000LE.

[0143] <Pendrop Test> As shown in Figure 9, in the pen drop test, the strength (pen drop strength) of the glass article 13 contained in the measurement sample 12 was evaluated by dropping the tip of a ballpoint pen 18 onto the measurement sample 12.

[0144] In the pen drop tests for Nos. 1-26 and 30-45, the measurement sample 12 was prepared by laminating a glass article 13, a PSA sheet 14, a PET plate 15, a PSA sheet 16, and a SUS plate 17 in that order. On the other hand, in the pen drop tests for Nos. 27-29, a protective layer (PET film, PA film, PI coating) was further added to the upper surface of the glass article 13 in the measurement sample 12. In other words, in the pen drop tests for Nos. 1-26 and 30-45, the tip of the ballpoint pen 18 came into direct contact with the glass article 13, while in the pen drop tests for Nos. 27-29, the tip of the ballpoint pen 18 came into direct contact with the protective layer.

[0145] The planar dimensions of the glass article 13, PSA sheets 14 and 16, PET sheet 15, and protective layer were all 50 mm x 50 mm. The planar dimensions of the SUS sheet 17 were 55 mm x 55 mm. The thicknesses of the glass article 13 and protective layer were as shown in Tables 2 to 8. The thickness of the PSA sheets 14 and 16 was 50 μm. The thickness of the PET sheet 15 was 125 μm. The thickness of the SUS sheet 17 was 3 mm.

[0146] In the pen drop test, five samples 12 for each of the No. 1 to 45 were prepared, and the tip of a ballpoint pen 18 was dropped into the center of each sample 12. At this time, the ballpoint pen 18 was dropped through the inner hole of a vertically held guide tube 19 to the sample 12 so that the tip of the ballpoint pen 18 fell perpendicular to the sample 12. The ballpoint pen 18 was a BIC orange EG0.7 with a ball diameter of 0.7 mm and a mass of 5.7 g. The height of the pen tip before dropping, relative to the top surface of the sample 12, was defined as the drop height H, and the initial value was set to 1 cm before dropping. If the glass article 13 contained in the sample 12 was not damaged by the drop of the ballpoint pen 18, the height was increased by 1 cm and the drop was repeated. In this way, the trial of increasing the drop height H and dropping was repeated until the glass article 13 contained in the sample 12 was damaged. Then, the 60% break height and the maximum break height were determined as the pen drop strength. The 60% break height is the drop height H when three of the five measurement samples 12 (glass articles 13) break. The maximum break height is the drop height H when all five of the five measurement samples 12 (glass articles 13) break.

[0147] According to the results of the pendrop test described above, it was confirmed that the examples with proper water treatment (Nos. 1-29) showed a 60% improvement in fracture height compared to the comparative examples (Nos. 30-45) where no water treatment was performed or no proper water treatment was performed.

[0148] <Bending fracture test> As shown in Figure 10, in the bending fracture test, the strength (two-point bending strength) was evaluated by so-called two-point bending, in which a measurement sample 20 made of glass was sandwiched between two plate-like bodies 21 and bent in a U-shape. The two-point bending strength was evaluated only for No. 2, 10, 18, 30, 34, and 38, and 30 measurement samples 20 corresponding to each of these glass articles were prepared. The planar dimensions of the measurement sample 20 were 140 mm × 70 mm. The thickness of the measurement sample 20 was 50 μm for No. 2, 10, 30, and 34, and 47 μm for No. 18 and 38, as described in Tables 2 to 8. The measurement sample 20 was then placed between the plate-like bodies 21 so as to bend in a U-shape along the longer side (the 140 mm side).

[0149] The two-point bending strength was calculated using the following formula (4), with respect to the distance D between the two plate-like bodies 21 when the glass article 20 broke due to compressive bending. The median, maximum, and minimum values ​​of the two-point bending strength were then determined. The median of the two-point bending strength is the middle value when the two-point bending strength data of the 30 measured samples are arranged in descending order. The maximum value of the two-point bending strength is the maximum value among the two-point bending strengths of the 30 measured samples. The minimum value of the two-point bending strength is the minimum value among the two-point bending strengths of the 30 measured samples. σ = 1.198[E × t / (Dt)] (4) However, in the formula, σ represents the two-point bending strength [MPa], E represents the Young's modulus of the glass article [MPa], and t represents the thickness of the glass article [mm].

[0150] The results of the bending fracture tests described above confirmed that chemically strengthened glass articles (No. 10, 18, 34, 38) exhibited improved two-point bending strength compared to unstrengthened glass articles (No. 2, 30). In particular, glass articles (No. 18, 38) that underwent a surface etching process after chemical strengthening showed a significant improvement in two-point bending strength. Therefore, from the viewpoint of improving both the pendrop strength and two-point bending strength of glass articles, it is preferable to perform a chemical strengthening process followed by an appropriate water treatment process. [Industrial applicability]

[0151] The glass articles of the present invention can be used, for example, as cover glass for smartphones, mobile phones, tablet computers, personal computers, digital cameras, touch panel displays, and other display devices, as well as for in-vehicle display devices and in-vehicle panels. [Explanation of Symbols]

[0152] 1. Glass articles 2. Compressive stress layer 3. Tensile stress layer 4 containers 5. Treated water 6. Glass for processing 7 Support stand 8 Constant temperature device 9 Laminate 10a protective layer 10b Reinforcement layer 11 Adhesive layer 12. Samples to be measured 13 Glassware 14 PSA seats 15 PET board 16 PSA seats 17 SUS board 18 Ballpoint pens 19 Guide tube 20. Measurement samples (glassware) 21 Plate-like body

Claims

1. A preparation step to prepare a glass for processing, which consists of alkali aluminosilicate glass containing alkali metal oxides as the glass composition, A chemical strengthening step in which a compressive stress layer is formed on the surface layer of the glass to be processed, After the chemical strengthening step, a surface etching step is performed in which the glass to be treated is etched in a range shallower than the compressive stress layer, A method for manufacturing a glass article, comprising a water treatment step of contacting the glass to be treated with treatment water for 0.5 hours or more but less than 15 hours after the surface etching step.

2. A method for manufacturing a glass article according to claim 1, wherein in the water treatment step, the glass for treatment is immersed in the treated water at 46 to 100°C.

3. A method for manufacturing a glass article according to claim 1, wherein in the water treatment step, the glass for treatment is immersed in the treated water at a temperature of 100°C or higher under a pressurized atmosphere.

4. A method for manufacturing a glass article according to any one of claims 1 to 3, wherein the electrical conductivity of the treated water in the water treatment step is 3 mS / m or less.

5. The method for manufacturing a glass article according to any one of claims 1 to 4, wherein the glass for processing is in the form of a plate or sheet with a thickness of 0.005 to 0.1 mm.

6. The method for manufacturing a glass article according to claim 5, further comprising a thinning step of thinning the glass to be processed to within the thickness range by etching before the chemical strengthening step.

7. The method for manufacturing a glass article according to claim 5, wherein the glass for processing is pre-formed within the thickness range by an overflow downdraw method.

8. A method for manufacturing a glass article according to any one of claims 1 to 7, wherein in the chemical strengthening step, the glass to be treated is brought into contact with an alkali metal nitrate to form a compressive stress layer having a maximum compressive stress of 100 MPa or more on its surface.

9. The method for manufacturing a glass article according to claim 8, wherein in the water treatment step, the temperature of the treated water is 50 to 95°C, and the contact time between the glass for treatment and the treated water is 0.5 to 10 hours.

10. The aforementioned glass for processing has a glass composition of SiO in mol%. 2 50-80%, Al 2 O 3 5-25%, B 2 O 3 0-35%, Li 2 O 0-20%, Na 2 O 1-20%, K 2 O Contains 0-10%, The method for producing a glass article according to claim 8 or 9, wherein in the chemical strengthening step, the alkali metal nitrate is a molten salt containing potassium nitrate.

11. A preparation step of preparing a glass for processing made of alkali aluminosilicate glass containing alkali metal oxide as the glass composition, The process includes a water treatment step in which the glass to be treated is brought into contact with treated water for 0.5 hours or more and less than 15 hours. A method for manufacturing a glass article, comprising immersing the glass for treatment in the treated water at a temperature of 100°C or higher under a pressurized atmosphere during the water treatment step.

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