WO2023181955A1 - Method for producing glass article, glass article, and layered product - Google Patents

Abstract

A method for producing a glass article which 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 0.5-15 hours, excluding 15 hours.

Description

Glass article manufacturing method, glass article and laminate

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

Chemically strengthened glass is often used as cover glass for devices such as various electronic terminals and display devices. Among this type of devices, so-called foldable type devices have been developed in which the display surface of the display can be folded, and chemically strengthened glass is also used for the cover glass of such foldable type devices. There may be cases where

By having a compressive stress layer on the surface formed by ion exchange treatment, chemically strengthened glass suppresses the formation and propagation of cracks on the surface and can obtain high strength. It is believed that the strength of tempered glass can be improved by adjusting the formation mode of such a compressive stress layer (for example, Patent Document 1).

International Publication No. 2013/088856

However, there is still room for improvement in obtaining higher impact resistance in glass articles used for cover glasses and the like. Particularly, in the case of a device that supports pen input using a stylus pen, local impact is likely to be applied to the glass article. Therefore, there is a need to develop a glass article that has high pen drop strength and can sufficiently withstand such pen input.

An object of the present invention is to provide a glass article having high pen drop strength.

(1) The method for manufacturing a glass article according to the present invention, which was devised to solve the above problems, includes a preparation step of preparing a processing glass made of alkali aluminosilicate glass containing an alkali metal oxide as a glass composition; The present invention is characterized by comprising a water treatment step of bringing the glass for treatment into contact with the treated water for 0.5 hours or more and less than 15 hours.

As a result of intensive research, the present inventors have found that when the glass for treatment is alkali aluminosilicate glass, by performing the water treatment process in which the glass for treatment is brought into contact with the treated water for the predetermined period of time, pen drops of the glass for treatment can be reduced. It was found that the strength was significantly improved. Such a pen drop strength improvement effect persists even after the water treatment step, that is, after the contact between the treatment glass and the treated water is removed. Therefore, a glass article having high pen drop strength can be provided.

(2) In the configuration of (1) above, in the water treatment step, it is preferable that the glass for treatment is immersed in treatment water at a temperature of 46 to 100°C.

By raising the temperature of the treated water in this way, the pen drop strength of the treated glass can be efficiently improved in a short time. In other words, the processing time (the contact time between the processing glass and the processing water) required to obtain the desired pen drop strength can be relatively shortened. Therefore, glass articles having high pen drop strength can be efficiently manufactured.

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

By raising the temperature of the treated water in this way, the pen drop strength of the treated glass can be efficiently improved in a short time. In other words, the processing time required to obtain the desired pen drop strength can be relatively shortened. Therefore, glass articles having high pen drop strength can be efficiently manufactured.

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

By using treated water with such low electrical conductivity, the pen drop strength of the treated glass can be further improved. Therefore, the pen drop strength of the glass article manufactured from the processing glass is further improved.

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

If the processing glass becomes thinner in this way, a glass article manufactured from the processing glass can also be suitably used for foldable type devices. On the other hand, the impact resistance of the glass article inevitably tends to decrease, making it more important to improve the pen drop strength. Therefore, the pen drop strength improving effect of the present invention becomes more useful.

(6) In the configuration of (5) above, it is also possible to further include a thinning step in which the glass for treatment is thinned to within the above thickness range (0.005 to 0.1 mm) by etching before the water treatment step. good.

(7) In the configuration of (5) above, the processing glass may be pre-formed within the above thickness range (0.005 to 0.1 mm) by an overflow down-draw method.

(8) In any of the configurations (1) to (7) above, before the water treatment step, the treatment glass 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 the surface. It is preferable to further include a chemical strengthening step.

In this way, the glass for processing and the glass article become chemically strengthened glass having a compressive stress layer on the surface. Therefore, the pen drop strength of the glass article can be improved, and the bending strength can also be improved. A glass article with improved bending strength as described above can also be suitably used for foldable type devices.

(9) In the configuration of (8) above, in the water treatment process, the temperature of the treated water is 50 to 95°C, and the contact time of the treatment glass and the treated water is 0.5 to 10 hours. is preferred.

In this way, the water treatment conditions are particularly suitable when the glass for treatment is chemically strengthened glass, and the pen drop strength of the glass article made of chemically strengthened glass can be efficiently improved.

(10) In the configuration of (8) or (9) above, the glass for treatment has, as a glass composition, SiO ₂ 50-80%, Al ₂ O ₃ 5-25%, B ₂ O ₃ 0-80%. In _the chemical strengthening process, the alkali metal nitrate _is preferably a molten salt containing potassium nitrate _.

In this way, even if the glass for processing is thin, both the pen drop strength and bending strength of the glass article can be easily improved.

(11) In any of the configurations (8) to (10) above, further comprising a surface layer etching step of etching the processing glass in a shallower range than the compressive stress layer after the ion exchange step and before the water treatment step. is preferred.

In this way, surface defects formed on the processing glass during the ion exchange process etc. can be reduced, so the pen drop strength and/or bending strength of the glass article can be improved.

(12) The glass article according to the present invention, which was invented to solve the above problems, is a plate-shaped or sheet-shaped glass article with a thickness of 0.005 to 0.1 mm, and has a spherical tip with a diameter of 0.7 mm. In a pen drop test in which a 5.7 g ballpoint pen having a weight of 5.7 g is dropped onto the main surface, the 60% fracture height is 5 cm or more.

In this way, a glass article with high pen drop strength that can sufficiently withstand pen input can be obtained.

(13) In the configuration of (12) above, it is preferable that the surface is provided with a compressive stress layer having a maximum compressive stress of 100 MPa or more.

In this way, the bending strength is improved in addition to the pen drop strength, so it can be suitably used for foldable type devices.

(14) The laminate according to the present invention, which was created to solve the above problems, is a glass article having the configuration of (12) or (13) above, and is laminated on at least one main surface of the glass article. It is characterized by comprising a protective layer or a reinforcing layer.

In this way, the protective layer can protect the glass article to achieve higher pen drop strength, and the reinforcing layer can reinforce the glass article to achieve higher bending strength.

According to the present invention, a glass article having high pen drop strength can be provided.

FIG. 1 is a schematic diagram showing a cross section of a glass article according to a first embodiment of the present invention. FIG. 3 is an image diagram of stress distribution in the thickness direction of the glass article according to the first embodiment of the present invention. It is a flow diagram of a manufacturing method of a glass article concerning a first embodiment of the present invention. It is a sectional view showing an embodiment of the water treatment process included in the manufacturing method of the glass article concerning the first embodiment of the present invention. It is a schematic diagram showing the cross section of the layered product concerning a second embodiment of the present invention. It is a flowchart of the manufacturing method of the glass article based on 3rd embodiment of this invention. It is a flowchart of the manufacturing method of the glass article based on 4th embodiment of this invention. It is a flowchart of the manufacturing method of the glass article based on 5th embodiment of this invention. FIG. 2 is a side view showing an embodiment of a pen drop test. FIG. 3 is a side view showing an embodiment of a bending fracture test.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that redundant explanation may be omitted by assigning the same reference numerals to corresponding components in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiments previously described can be applied to other parts of the configuration. Furthermore, in addition to the combinations of configurations specified in the description of each embodiment, configurations of a plurality of embodiments may be partially combined even if not explicitly specified, as long as no particular problem arises in the combination.

(First embodiment)
<Glass articles>
As shown in FIG. 1, the glass article 1 according to the first embodiment has a plate shape or a sheet shape. The thickness t of the glass article 1 is not particularly limited, but is preferably 0.005 to 0.1 mm. The invention is particularly useful for such thin glasses.

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

In this embodiment, the glass article 1 is chemically strengthened glass that has been chemically strengthened by ion exchange, and includes a compressive stress layer 2 and a tensile stress layer 3. Thereby, in addition to improving the pen drop strength, it is possible to improve the bending strength.

When the glass article 1 is chemically strengthened glass, the two-point bending strength of the glass article 1 is preferably 900 MPa or more. The two-point bending strength of the glass article 1 is more preferably 1000 MPa or more, 1100 MPa or more, or 1200 MPa or more.

The compressive stress layer 2 is formed on the surface layer portion 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, that is, 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-shaped or sheet-shaped glass surface excluding the end surfaces.

An example of the stress distribution of the glass article 1 is shown in FIG. 2. In FIG. 2, the vertical axis shows the stress value, and the horizontal axis shows the depth from the surface. Note that although FIG. 2 is an image diagram schematically showing the stress distribution by linear approximation, the stress distribution may be approximated by other functions (for example, a single curve function or a combination of multiple curve functions). Further, in this specification, unless otherwise specified, the magnitude of each stress is indicated by an absolute value. The stress distribution of the glass article 1 is not limited to the embodiment shown in FIG. 2 .

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

The tensile stress layer 3 includes a first region A1 where the tensile stress varies in the thickness direction of the glass article 1, and a second region A2 where 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 the absolute value of the tensile stress gradually increases as the depth increases (the negative number shown in FIG. 2 In the title, it is a region (gradually decreasing). The second region A2 extends deeper than the tensile stress convergence depth DCT, and is a region where the tensile stress is constant in the thickness direction. Note that "tensile stress is constant" refers to the amount of change in stress in the depth direction being 0.5 MPa/μm or less, and the amount of change is, for example, the differential of stress sampled at intervals of 0.1 μm in depth. It can be calculated by the value.

The depth DOC of the compressive stress layer 2 of the glass article 1 is preferably 20 μm or less, 1 μm or more and 19 μm or less, 2 μm or more and 18 μm or less, 3 μm or more and 17.5 μm or less, and 4 μm or more and 17 μm or less. As a result of various studies by the inventors regarding the threshold value of the compressive stress value on the surface and the depth of the compressive stress layer that does not cause a dangerous fracture mode at the time of fracture, for example, in thin glass of 0.1 mm or less, the depth of the compressive stress layer is It has been found that it is effective to make the thickness 20 μm or less. By doing this, it is possible to ensure safety while having sufficient strength against bending.

The maximum compressive stress CS in the compressive stress layer 2 of the glass article 1 is preferably 100 MPa or more, 200 MPa or more and 1000 MPa or less, 300 MPa or more and 900 MPa or less, 400 MPa or more and 870 MPa or less, 430 MPa or more and 850 MPa or less, or 450 MPa or more and 800 MPa or less. By setting CS within such a range, high bending strength can be obtained.

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

The tensile stress convergence depth DCT can be calculated using the following formula (3).
DCT=(CS+CT)/(CS/DOC) (3)

The upper limit range of 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 Below, 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 of 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, strength against bending can be ensured while ensuring safety to prevent a dangerous failure mode at the time of failure.

Note that numerical values related to stress such as CS, DOC, DCT, CT, etc. can be derived by measuring the stress distribution of the glass using a measuring device such as FSM-6000 or SLP-1000 manufactured by Orihara Seisakusho, for example.

The lower limit range of the Young's modulus of the glass article 1 is preferably 55 GPa or more, 57 GPa or more, 60 GPa or more, or 62 GPa or more. The upper limit range of the Young's modulus of the glass article 1 is preferably 90 GPa or less.

As a method for forming the glass article 1 into a sheet, the overflow down-draw method is preferable from the viewpoint of cost and production volume, but the thinner the sheet, the more rapidly the glass is cooled, the lower the CS, and the deeper the DOC tends to be. . It is also known that when thin glass is ion-exchanged, it is difficult to obtain a high CS compared to thick glass because there is less glass inside to suppress the volumetric expansion of the ion-exchanged portion. Therefore, for thin glass, it is not easy to achieve both high CS and shallow DOC at a high level, which is more than just a matter of design. That is, it is necessary to appropriately select the glass composition, glass forming method, and strengthening conditions. Therefore, for the glass article 1, an alkali aluminosilicate glass suitable for chemical strengthening is suitable, and a composition that can obtain a particularly high surface compressive stress value among alkali aluminosilicate glasses is suitable. A compositional balance is preferred that achieves a high liquidus viscosity to enable.

The glass article 1 has, for example, a glass composition of 50 to 80% SiO _{2 ,} 5 to 25% Al ₂ O _{3 ,} 0 to 35% B ₂ O _{3 ,} 0 to 20% Li ₂ O, and 0 to 20% Na ₂ O as a glass composition. It is preferable to contain 1 to 20% of K ₂ O and 0 to 10% of K 2 O.

SiO ₂ is a component that forms the glass network. If the content of SiO ₂ is too low, it becomes difficult to vitrify, and the coefficient of thermal expansion becomes too high, making it easy to reduce thermal shock resistance. Therefore, the preferable lower limit range of SiO ₂ is 50% or more, 55% or more, 57% or more, 59% or more, especially 61% or more in terms of mol%. On the other hand, if the content of SiO ₂ is too large, 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 surrounding materials. Therefore, the preferable upper limit range of SiO ₂ is 80% or less, 70% or less, 68% or less, 66% or less, 65% or less, particularly 64.5% or less.

Al ₂ O ₃ is a component that improves ion exchange performance, and is also a component that increases strain point, Young's modulus, fracture toughness, and Vickers hardness. Therefore, the preferable lower limit range of Al ₂ O ₃ is 5% or more, 8% or more, 10% or more, 11% or more, and 11.2% or more in terms of mol%. On the other hand, if the content of Al ₂ O ₃ is too large, the high temperature viscosity increases and the meltability and moldability tend to decrease. Furthermore, devitrification crystals tend to precipitate in the glass, making it difficult to form it into a plate shape using an overflow down-draw method or the like. In particular, when a glass plate is formed by an overflow down-draw method using an alumina-based refractory as the molded refractory, spinel devitrification crystals tend to precipitate at the interface with the alumina-based refractory. Furthermore, the acid resistance also decreases, making it difficult to apply to acid treatment steps. Therefore, the preferable upper limit range of Al ₂ O ₃ is 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, especially 18 .9% or less. By setting the content of Al ₂ O ₃ , which has a large influence on ion exchange performance, within a suitable range, it becomes easy to design a high CS/DOC value even in thin glass.

B ₂ O ₃ is a component that lowers high-temperature viscosity and density, stabilizes the glass, makes it difficult for crystals to precipitate, and lowers the liquidus temperature. It is also a component that suppresses Young's modulus and increases bending strength and crack resistance. However, if the content of B ₂ O ₃ is too high, ion exchange treatment tends to cause surface discoloration called discoloration, decrease in water resistance, and decrease in the compressive stress value of the compressive stress layer. There is. Therefore, the preferable lower limit range of B ₂ O ₃ is 0% or more, 0.01% or more, 0.02% or more, 0.1% or more, 0.3% or more in mol%, and the preferable upper limit range is is 35% or less, 30% or less, 25% or less, 22% or less, 20% or less, particularly 15% or less. In addition, from the viewpoint of giving priority to increasing CS, the content of B ₂ O ₃ can be more preferably 0.2 to 5% and 0.3 to 1%. In addition, from the viewpoint of improving chemical durability for the purpose of suppressing defects during etching processing, the upper limit range of the B ₂ O ₃ content is preferably 1% or more, 1.5% or more, and 2% or more. The lower limit range can be 5% or less, 4.5% or less, 4% or less, or 3% or less. On the other hand, from the viewpoint of giving priority to suppressing Young's modulus, the content of B ₂ O ₃ can be more preferably 10 to 25%, 15 to 23%, or 18 to 22%.

Li ₂ O is an ion exchange component, and in particular is a component that ion exchanges Li ions contained in the glass with K ions in the molten salt to obtain a high surface compressive stress value. Moreover, Li ₂ O is a component that lowers high temperature viscosity and improves meltability and moldability. Therefore, the preferable lower limit range of Li ₂ O 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% by mole. % or more, 7.3% or more, 7.5% or more, 7.8% or more, especially 8% or more. Therefore, the preferable upper limit range of Li ₂ O 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, 8.9% or less.

Na ₂ O is an ion exchange component, and also a component that lowers high temperature viscosity and improves meltability and moldability. Na ₂ O is also a component that improves devitrification resistance and reaction devitrification with molded refractories, especially alumina refractories. If the content of Na ₂ O is too low, the meltability will be reduced, the coefficient of thermal expansion will be too low, and the ion exchange rate will tend to be reduced. Therefore, the preferred lower limit range of Na ₂ O 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 in terms of mol%. , 11% or more, 12% or more, especially 12.5% or more. On the other hand, if the content of Na ₂ O is too large, the viscosity at which phase separation occurs tends to decrease. In addition, acid resistance may be lowered, or the glass composition may lack component balance, resulting in a lower devitrification resistance. Therefore, the preferred upper limit ranges of Na ₂ O 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, especially It is 15% or less.

K ₂ O is a component that lowers high temperature viscosity and improves meltability and moldability. Furthermore, it is a component that improves devitrification resistance and increases Vickers hardness. However, if the content of K ₂ O is too large, the viscosity at which phase separation occurs tends to decrease. Furthermore, acid resistance tends to decrease, the glass composition lacks component balance, and devitrification resistance tends to decrease. Therefore, the preferable lower limit range of K ₂ O 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% by mole. % or more, 2% or more, 2.5% or more, 3% or more, especially 3.5% or more, and the preferable upper limit range is 10% or less, 5.5% or less, 5% or less, especially 4.5%. less than

Both Li ₂ O and Na ₂ O are components that obtain a high surface compressive stress value by ion exchange with K ions in the molten salt, and either of them is an essential component for the present invention. Therefore, the preferable lower limit range of Li ₂ O + Na ₂ O 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% by mole. % 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, especially 18.5% or more. On the other hand, if the content of Li ₂ O + Na ₂ O is too large, the coefficient of thermal expansion becomes too high and the thermal shock resistance tends to decrease. Moreover, the component balance of the glass composition may be disrupted, and the devitrification resistance may be reduced on the contrary. Therefore, a preferable upper limit range of Li ₂ O+Na ₂ O is 20% or less, particularly 19% or less.

In addition to the above components, the glass article 1 may also contain, for example, the following components as a glass composition.

MgO is a component that lowers high-temperature viscosity, increases meltability and moldability, and increases strain point and Young's modulus. Among alkaline earth metal oxides, MgO is a component that has the greatest effect on improving ion exchange performance. be. However, if the content of MgO is too large, the density and coefficient of thermal expansion tend to increase, and the glass tends to devitrify. Therefore, the preferable upper limit range of MgO is 12% or less, 10% or less, 8% or less, 6% or less, especially 5% or less. In addition, when introducing MgO into the glass composition, the preferable lower limit range of MgO is 0.1% or more, 0.5% or more, 1% or more, especially 2% or more in mol%.

Compared to other components, CaO has a large effect of lowering high temperature viscosity, increasing meltability and moldability, and increasing strain point and Young's modulus without reducing devitrification resistance. The content of CaO is preferably 0 to 10%. However, if the content of CaO is too large, the density and coefficient of thermal expansion will increase, and the glass composition will lack component balance, making the glass more likely to devitrify or deteriorate its ion exchange performance. Therefore, the preferred content of CaO is 0 to 5%, 0.01 to 4%, 0.1 to 3%, particularly 1 to 2.5% in terms of mol%.

SrO is a component that lowers high-temperature viscosity, improves meltability and moldability, and increases strain point and Young's modulus without reducing devitrification resistance. However, if the content of SrO is too large, the density and coefficient of thermal expansion will increase, the ion exchange performance will decrease, and the component balance of the glass composition will be lacking, making the glass more likely to devitrify. The preferred content range of SrO is 0 to 5%, 0 to 3%, 0 to 1%, particularly 0 to less than 0.1% in terms of mol%.

BaO is a component that lowers high-temperature viscosity, improves meltability and moldability, and increases strain point and Young's modulus without reducing devitrification resistance. However, if the content of BaO is too large, the density and coefficient of thermal expansion will increase, the ion exchange performance will decrease, and the component balance of the glass composition will be lacking, making the glass more likely to devitrify. The preferred content range of BaO is 0 to 5%, 0 to 3%, 0 to 1%, particularly 0 to less than 0.1% in terms of mol%.

ZnO is a component that enhances ion exchange performance, and is particularly effective in increasing compressive stress values. It is also a component that reduces high temperature viscosity without reducing low temperature viscosity. However, if the ZnO content is too large, the glass tends to undergo phase separation, the devitrification resistance decreases, the density increases, and the stress depth of the compressive stress layer decreases. Therefore, the content of ZnO is preferably 0 to 6%, 0 to 5%, 0 to 1%, 0 to 0.5%, particularly 0 to less than 0.1% in terms of mol%.

ZrO ₂ is a component that significantly increases ion exchange performance, and also increases viscosity near the liquidus viscosity and strain point, but if its content is too large, there is a risk that devitrification resistance will decrease significantly. However, there is a risk that the density may become too high. Therefore, the preferable upper limit range of ZrO ₂ is 10% or less, 8% or less, 6% or less, particularly 5% or less in terms of mol%. In addition, when it is desired to improve the ion exchange performance, it is preferable to introduce ZrO ₂ into the glass composition. In that case, the preferable lower limit range of ZrO ₂ is 0.001% or more, 0.01% or more, 0.5%. %, especially 1% or more.

P ₂ O ₅ is a component that enhances ion exchange performance, and particularly increases the stress depth of the compressive stress layer. It is also a component that suppresses Young's modulus to a low level. However, if the content of P ₂ O ₅ is too large, the glass tends to undergo phase separation. Therefore, the preferable upper limit range of P ₂ O ₅ is 10% or less, 8% or less, 6% or less, 4% or less, 2% or less, 1% or less, particularly less than 0.1% in terms of mol%.

As a clarifier, one or more selected from the group of As ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , F, Cl, and SO ₃ (preferably the group of SnO ₂ , Cl, and SO ₃ ) is used in an amount of 0 to 2. 30000 ppm (3%) may be introduced. The content of SnO ₂ +SO ₃ +Cl is preferably 0 to 10,000 ppm, 50 to 5,000 ppm, 80 to 4,000 ppm, 100 to 3,000 ppm, particularly 300 to 3,000 ppm, from the viewpoint of accurately enjoying the clarification effect. Here, "SnO ₂ +SO ₃ +Cl" refers to the total amount of SnO ₂ , SO ₃ and Cl.

The preferred content range of SnO ₂ is 0 to 10,000 ppm, 0 to 7,000 ppm, particularly 50 to 6,000 ppm. The preferred content range of Cl is 0 to 1500 ppm, 0 to 1200 ppm, 0 to 800 ppm, 0 to 500 ppm, particularly 50 to 300 ppm. The preferred content range for SO ₃ is 0 to 1000 ppm, 0 to 800 ppm, particularly 10 to 500 ppm.

Rare earth oxides such as Nd ₂ O ₃ and La ₂ O ₃ are components that increase Young's modulus, and when a complementary color is added, they are decolored and can control the color of the glass. However, the cost of the raw material itself is high, and if a large amount is introduced, the devitrification resistance tends to decrease. Therefore, the content of the rare earth oxide is preferably 4% or less, 3% or less, 2% or less, 1% or less, particularly 0.5% or less.

From environmental considerations, it is preferable that the glass article 1 substantially not contain As ₂ O ₃ , F, PbO, or Bi ₂ O ₃ . Here, "substantially does not contain As ₂ O ₃ " means that although As ₂ O ₃ is not actively added as a glass component, it is allowed to be mixed in at an impurity level, and specifically, , indicates that the content of As ₂ O ₃ is less than 500 ppm. "Substantially no F" means that although F is not actively added as a glass component, it is allowed to be mixed in at an impurity level. Specifically, it means that the F content is less than 500 ppm. refers to something. "Substantially no PbO" means that although PbO is not actively added as a glass component, it may be mixed in at an impurity level. Specifically, if the PbO content is less than 500 ppm, refers to something. "Substantially does not contain Bi ₂ O ₃ " means that although Bi ₂ O ₃ is not actively added as a glass component, it is allowed to be mixed in at an impurity level. Specifically, Bi ₂ O 3 is not actively added as a glass component. It means that the O ₃ content is less than 500 ppm.

As an example, the glass article 1 may not contain B ₂ O ₃ as a glass composition, or the content of B ₂ O ₃ may be limited to a very small amount. That is, the glass article 1 has a glass composition, in mol%, of SiO ₂ 50-80%, Al ₂ O ₃ 5-25%, B ₂ O ₃ 0-1%, Li ₂ O 0-20%, Na ₂ O. It may contain 1 to 20% of K ₂ O and 0 to 10% of K 2 O.

As another example, the glass article 1 may include B ₂ O ₃ as an essential component in the glass composition. That is, the glass article 1 has, as a glass composition, SiO ₂ 50-80%, Al ₂ O ₃ 5-25%, B ₂ O ₃ 1-5%, Li ₂ O 0-20%, Na ₂ It may contain 1 to 20% of O and 0 to 10% of K ₂ O.

Note that if the glass article 1 contains B ₂ O ₃ as an essential component, there is a concern that the formability of the glass will decrease, so the content of other components such as Al ₂ O ₃ may be adjusted to maintain balance. may be restricted. That is, the glass article 1 has, as a glass composition, SiO ₂ 50-80%, Al ₂ O ₃ 5-10%, B ₂ O ₃ 1-5%, Li ₂ O 0-20%, Na ₂ It may contain 1 to 20% of O and 0 to 10% of K ₂ O.

<Method for manufacturing glass articles>
As shown in FIG. 3, the method for manufacturing a glass article according to the first embodiment includes a preparation step S1, a chemical strengthening step S2, and a water treatment step S3 in this order.

In the preparation step S1, glass (hereinafter referred to as processing glass) that is the source of the above-mentioned glass article 1 is prepared. The processing glass is a glass having the same shape and size and glass composition as the glass article 1 described above.

The glass for processing is obtained by cutting and processing a plate-like or sheet-like mother glass obtained by a forming method such as an overflow down-draw method, a slot down-draw method, a float method, or a redraw method into small glass pieces. In order to obtain a smooth surface, it is preferable to use an overflow down-draw method as the molding method. Furthermore, if the overflow down-draw method is used, it is easy to mold glass for processing with a thickness of 0.005 to 0.1 mm without polishing (including mechanical polishing and etching) after molding. Note that when molded by the overflow down-draw method, the processing glass has a molding convergence surface inside.

It is preferable that the end face of the glass for treatment is subjected to chamfering and strength improvement treatment by polishing, heat treatment, etching, etc. The main surface of the glass for processing may be polished, but for example, if the main surface has been formed smooth in advance by the overflow down-draw method, or if it has been formed with uniform thickness and precision, the main surface may be polished. may be used without polishing, that is, with the unpolished surface. Note that if the glass is formed by the overflow down-draw method and is not polished, the main surface of the glass for processing will be the fire-finished surface.

In the chemical strengthening step S2, the glass for treatment is subjected to ion exchange treatment. In this embodiment, the glass for treatment is immersed in a molten salt for ion exchange treatment. By making the glass for treatment into chemically strengthened glass through ion exchange treatment in this way, the bending strength of the glass for treatment is improved.

The molten salt is a salt containing a component that can be ion-exchanged with the component in the chemically strengthened glass, and is typically an alkali metal nitrate. Examples of the alkali metal nitrates include NaNO ₃ , KNO ₃ , LiNO _{3 ,} and the like, and each of these can be used alone (at 100% by mass) or in combination. When mixing multiple types of alkali metal nitrates, the mixing ratio may be determined arbitrarily, but for example, NaNO ₃ 5 to 95%, KNO ₃ 5 to 95%, preferably NaNO ₃ 30 to 80%, KNO 3 in mass %. ₃ 20-70%, more preferably NaNO ₃ 50-70% and KNO ₃ 30-50%.

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, and 7 to 100 minutes. Of course, the conditions such as the temperature of the molten salt and the immersion time can be changed as appropriate depending on the glass composition, etc., within a range that allows the above-mentioned stress characteristics to be obtained.

In the water treatment step S3, the glass for treatment is brought into contact with the treated water for 0.5 hours or more and less than 15 hours. By bringing the treated glass into contact with treated water in this manner, the pen drop strength of the treated glass is improved. Further, since the pen drop strength of the treatment glass is maintained even after the water treatment step S3, the pen drop strength of the glass article 1 manufactured from the treatment glass is also improved. Note that if the contact time between the glass for treatment and the treated water (hereinafter referred to as water treatment time) is too short or too long, the pen drop strength improvement effect cannot be fully enjoyed. Therefore, it is important that the water treatment time be within the above numerical range.

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

The temperature of the treated water is, for example, 10 to 100°C. The lower limit range of the temperature of the treated water is preferably 20°C or higher, 30°C or higher, 40°C or higher, or 46°C or higher. The upper limit range of the temperature of the treated water 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 to achieve the desired pen drop strength tends to decrease.

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

The electrical conductivity of the treated water is preferably 3 mS/m or less. The electrical conductivity of the treated water is more preferably 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 pen drop strength of the treated glass. The treated water preferably does not contain detergents and their materials (eg, surfactants, water softeners, sequestrants, pH adjusters, stabilizers), and the like.

An example of an embodiment of the water treatment step S3 is shown in FIG. 4. As shown in FIG. 4, a glass for treatment 6 is immersed in treated water 5 stored in a container 4. In the treated water 5, for example, a plurality of pieces of glass for treatment 6 are supported in a vertical position by support stands 7 at predetermined intervals in the thickness direction. Then, the container 4 containing the glass for treatment 6 and the treated water 5 is housed in a constant temperature device (temperature adjustment device) 8 that is maintained at a prescribed temperature for a predetermined period of time, and the glass for treatment 6 is subjected to water treatment. .

The method of bringing the treated water into contact with the treated glass is not particularly limited, but as mentioned above, it is preferable to adopt a method of immersing the treated glass in the treated water stored in a container. At this time, it is preferable to leave the glass for treatment still in the treatment water without applying external vibrations such as ultrasonic waves to the treatment water. By immersing the glass in the treated water in this manner, the entire glass for treatment can be efficiently brought into contact with the treated water, making it easier to enjoy the effect of improving pen drop strength. The treated water may be sprayed onto the glass for treatment from a nozzle or the like, or the water may be flowed over the entire surface of the glass for treatment.

The glass for treatment may be moved relative to the treated water. Specifically, for example, the glass for treatment immersed in the treatment water may be moved within the treatment water, or the glass for treatment may be moved within an area where the treatment water is sprayed and supplied by a nozzle or the like.

(Second embodiment)
<Laminated body>
As shown in FIG. 5, a laminate 9 according to the second embodiment includes the above-mentioned glass article 1, a protective layer 10a laminated on one main surface 1a (for example, the front surface) of the glass article 1, and A reinforcing layer 10b laminated on the other main surface 1a (for example, the back surface) is provided. In this way, since the glass article 1 is protected by the protective layer 10a, higher pen drop strength can be achieved. Moreover, the bending strength of the glass article 1 can be improved by the reinforcing layer 10b, and damage during bending can be suppressed. It is preferable that the protective layer 10a is provided on the front side of the glass article 1 that a pen or the like comes into contact with, and the reinforcing layer 10b is provided on the back side of the glass article 1 that a pen or the like does not come into contact with. Note that only one of the protective layer 10a and the reinforcing layer 10b may be provided.

Examples of the protective layer 10a and the reinforcing layer 10b include plate-shaped or sheet-shaped resins, metals, glass, etc., and these can be formed in a single layer or in a combination of multiple layers. However, when applying the laminate 9 to a foldable type device, the protective layer 10a and the reinforcing layer 10b are preferably made of resin that easily imparts flexibility.

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. Examples of the resin material included in the protective layer 10 include polycarbonate (PC), acrylic, polyethylene terephthalate (PET), polyether ether ketone (PEEK), polyamide (PA), polyvinyl chloride (PVC), and polyethylene (PE). ), polypropylene (PP), polyethylene naphthalate (PEN), polyimide (PI), cycloolefin polymer (COP), epoxy, and the like.

The protective layer 10a and the reinforcing layer 10b are, for example, laminated on the main surface 1a of the glass article 1 via the 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 the material for the adhesive layer 11 include acrylic adhesive, silicone adhesive, rubber adhesive, ultraviolet curable acrylic adhesive, ultraviolet curable epoxy adhesive, thermosetting epoxy adhesive, and heat-curable epoxy adhesive. Examples include curable melamine adhesives, thermosetting phenolic adhesives, ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), and cycloolefin polymers (COP). Note that the protective layer 10 may be directly formed on the main surface 1a of the glass article 1 by any method such as coating, without using the adhesive layer 11.

(Third embodiment)
<Method for manufacturing glass articles>
As shown in FIG. 6, the method for manufacturing a glass article according to the third embodiment includes, in this order, a preparation step S11, a chemical strengthening step S12, a surface layer etching step S13, and a water treatment step S14. Among these steps, the steps other than the surface layer etching step S13 are the same as the corresponding steps in the above-described embodiment, so detailed explanations will be omitted.

The surface layer etching step S13 is a step of etching the processing glass in a shallower range than the compressive stress layer after the chemical strengthening step S12 and before the water treatment step S14. By performing the surface layer etching step S13 in this manner, it is possible to reduce surface defects formed in the processing glass in the chemical strengthening step S12 and the like. Therefore, the pen drop strength and/or bending strength of processing glass and glass articles can be improved.

In the surface layer etching step S13, for example, the entire processing glass is immersed in a liquid etching medium, and the entire surface of the processing glass is wet-etched. According to such a treatment, the entire glass for treatment can be uniformly etched, so that it is possible to suppress the occurrence of variations in thickness due to the etching treatment. When such an etching treatment is performed, the surface of the glass for treatment is constituted by an etched surface.

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

As the 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 for glass is high and production efficiency is good.

The aqueous solution containing HF is, for example, an aqueous solution containing only HF, or a combination of HF and HCl, HF and HNO ₃ , HF and H ₂ SO ₄ , or HF and NH ₄ F. The concentration of each compound of HF, HCl, HNO ₃ , H ₂ SO ₄ and NH ₄ F is preferably 0.1 to 30 mol/L. In etching using an aqueous solution containing HF, fluoride _containing a glass component is produced _as a by-product, which can reduce the etching rate and cause defects _. By forming a mixed acid with other acids, it is possible to decompose the by-products and suppress a decrease in productivity. When etching is performed using an acidic aqueous solution, the temperature of the acidic aqueous solution is, for example, 10 to 30° C., and the time for immersing the glass to be treated is preferably, for example, 0.1 to 60 minutes.

As the alkaline etching medium, an alkaline aqueous solution containing NaOH or KOH can be used. Since the alkaline aqueous solution has a relatively lower etching rate for glass than the etching medium containing HF described above, it has the advantage that the amount of etching can be easily controlled precisely. This is particularly suitable when it is necessary to control the thickness, DOC, etc. of the glass in units of several μm.

The concentration of the alkaline component in the aqueous solution containing NaOH or KOH is preferably 1 to 20 mol/L. When etching is performed using an alkaline aqueous solution, the temperature of the alkaline aqueous solution is, for example, 10 to 130° C., and the time for immersing the glass to be treated is preferably, for example, 0.5 to 120 minutes. Note that when increasing the etching rate to increase productivity, it is preferable to heat the aqueous alkaline solution to 80° C. or higher. On the other hand, if it is desired 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, when the etching rate is more important, it is preferable to use an aqueous solution of NaOH.

The removed thickness of the surface layer of the glass for treatment in the surface layer etching step S13 is preferably 0.25 μm or more and 3 μm or less. The removed thickness of the surface layer of the glass for treatment is more preferably 0.4 μm or more and 2.7 μm or less, 0.6 μm or more and 2.5 μm or less, and 0.8 μm or more and 2.3 μm or less. By setting the etching amount within such a range, it is possible to reduce the amount of variation in the maximum compressive stress and compressive stress depth before and after etching.

It is preferable that the entire surface of the glass article manufactured through the surface layer etching step S13, that is, both the front and back principal surfaces and the end surfaces, be etched surfaces. In this way, defects are reduced over the entire surface of the glass article and high strength, especially high pen drop strength, can be achieved.

(Fourth embodiment)
<Method for manufacturing glass articles>
As shown in FIG. 7, the method for manufacturing a glass article according to the fourth embodiment includes a preparation step S21, a thinning step S22, a chemical strengthening step S23, a surface layer etching step S24, and a water treatment step S25. Prepare in this order. Among these, the steps other than the thinning step S22 are the same as the corresponding steps in the above-described embodiment, and therefore detailed explanations will be omitted. Note that the surface layer etching step S24 may not be provided.

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

In the thinning step S22, for example, the entire processing glass is immersed in a liquid etching medium, and the entire surface of the processing glass is wet-etched. As the etching medium, the etching medium used in the surface layer etching step S24 can be similarly used.

The removed thickness of the surface layer of the processing glass in the thinning step S22 is not particularly limited because it depends on the original thickness (initial thickness) of the processing glass before the thinning step S22. The thickness may be larger than the removal thickness of the surface layer.

(Fifth embodiment)
<Method for manufacturing glass articles>
As shown in FIG. 8, the method for manufacturing a glass article according to the fifth embodiment includes a preparation step S31, a thinning step S32, and a water treatment step S33 in this order. Each step is similar to the corresponding step in the above-described embodiment, but this embodiment differs in that it does not include a chemical strengthening step.

According to such a manufacturing method, in the water treatment step S33, the unreinforced treatment glass comes into contact with the treated water. In this case, the pen drop strength of the treated glass tends to be higher than when chemically strengthened treated glass is brought into contact with treated water. Therefore, high pen drop strength can be obtained even in a glass article manufactured through the water treatment step S33 in which unstrengthened treatment glass is brought into contact with treated water. That is, in the present invention, the glass article is not limited to chemically strengthened glass. However, chemically strengthened glass articles tend to have higher bending strength. Therefore, from the viewpoint of achieving both pen drop strength and bending strength, the glass article is preferably chemically strengthened glass.

In the present embodiment, the case where the thinning step S32 is provided is illustrated, but in the case where a processing glass preformed to a thickness of 0.005 to 0.1 mm by an overflow down-draw method or the like can be prepared in the preparation step S31, , it is not necessary to provide the thinning step S32.

(Sixth embodiment)
<Method for manufacturing glass articles>
The method for manufacturing a glass article according to the sixth embodiment shows a modification of the water treatment process in the above embodiment. In the above 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.

An example of the water treatment step of the present embodiment includes immersing the glass for treatment in treatment water at a temperature of 100° C. or higher in a pressurized atmosphere. Specifically, the glass for treatment is immersed in treated water stored in a container. Thereafter, with this container housed in a pressurizing device, the inside of the pressurizing device is pressurized and the treated water is heated to 100° C. or higher. By controlling the temperature of the treated water to 100° C. or higher in this way, the effect of shortening the water treatment time until the desired pen drop strength is obtained can be expected.

The temperature of the treated water is preferably higher than 100°C and lower than 200°C. The lower limit range of the temperature of the treated water is more preferably 105°C or higher, 110°C or higher, or 120°C or higher. The upper limit range of the temperature of the treated water is more preferably 190°C or lower, 180°C or lower, or 170°C or lower.

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

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

Instead of immersing the glass for treatment in treated water at 100°C or higher, the treated water may be converted into superheated steam at 100°C or higher and injected onto the glass for treatment.

Although the embodiments of the present invention have been described, the embodiments of the present invention are not limited thereto, and various changes can be made without departing from the gist of the present invention.

In the above embodiments, the shape of the glass article is not particularly limited. The shape of the glass article can be, for example, square, rectangular, circular, oval, etc. in plan view.

In the above embodiments, the glass article may be subjected to three-dimensional bending as necessary. Specifically, by performing a three-dimensional bending process on the glass for processing in whole or in part in advance, a three-dimensional bent shape can be imparted to the glass article that is finally manufactured.

In the above embodiment, the case where the chemical strengthening process (ion exchange treatment) is performed once is illustrated, but the chemical strengthening process may be performed twice or three times or more. Further, heat treatment may be performed before and after ion exchange. By heat treatment, the depth of the compressive stress layer and the like can be controlled by relaxing stress and promoting ion diffusion. When performing a chemical strengthening process, it is preferable that the glass for treatment is washed and dried after the chemical strengthening process and before the water treatment process. In addition, when chemical strengthening is performed multiple times as described above, the stress distribution of the glass article after strengthening is at least one of a bending point, a local maximum value, a local minimum value, or an inflection point in the region of the compressive stress layer 2. may have one or more.

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 for the thickness t of the glass article is set relatively large (for example, when DOC≧0.20t), the stress distribution in the tensile stress layer 3 has a minimum value at the center of the thickness of the glass article. The distribution shape can be along a convex quadratic curve.

In the above embodiments, the stress distribution of the glass article may be asymmetric between the front and back sides. Asymmetrical stress distribution on the front and back surfaces can be achieved by polishing one main surface of a glass article after strengthening more than the other, or by chemically strengthening one main surface with a film that inhibits ion exchange. It will be done.

Hereinafter, the glass article according to the present invention will be explained based on Examples. Note that the following examples are merely illustrative, and the present invention is not limited to the following examples in any way.

A sample was prepared as follows. First, a processing glass having the glass composition shown in Table 1 was prepared. Note that the Young's modulus shown in Table 1 is a value measured by a resonance method.

Specifically, glass raw materials were prepared to have the composition shown in Table 1 and melted in a test melting furnace. Thereafter, the obtained molten glass was formed into a plate or sheet by an overflow down-draw method and cut into a predetermined size to obtain a glass for processing.

Next, the plate-shaped or sheet-shaped glass for processing was processed under the conditions listed in Tables 2 to 8 to produce plate-shaped or sheet-shaped glass articles. The thinning process and the surface layer etching process were performed by immersing the glass for treatment in an HF aqueous solution. The chemical strengthening process was performed by immersing the glass for treatment in a 100% KNO ₃ molten salt. The water treatment step was performed by immersing the glass for treatment in treated water. In Tables 2 to 8, No. Nos. 1 to 29 are examples of the present invention, and No. 1 to 29 are examples of the present invention. 30 to 45 are comparative examples.

<Method for manufacturing glass article or laminate>
(1) No. of Table 2. In Examples 1 to 6, the treated glass was subjected to a water treatment process to produce glass articles. No. of Table 2 In Examples 7 and 8, a glass article was manufactured by subjecting the treated glass to a thinning process and a water treatment process in this order. In other words, No. 2 in Table 2. In Nos. 1 to 8, no chemical strengthening process was performed on the glass for treatment. In addition, No. In Nos. 1 to 6, the initial thickness of the processing glass matches the thickness of the glass article; In Nos. 7 and 8, the thickness of the processing glass after the thinning step matches the thickness of the glass article.

(2) No. of Table 3. In steps 9 to 14, the treated glass was subjected to a chemical strengthening process and a water treatment process in this order to produce glass articles. No. of Table 3 In Nos. 15 and 16, glass articles were manufactured by subjecting the treated glass to a thinning process, a chemical strengthening process, and a water treatment process in this order. In addition, No. Nos. 9 to 14, the initial thickness of the processing glass matched the thickness of the glass article; In Nos. 15 and 16, the thickness of the processing glass after the thinning process matches the thickness of the glass article.

(3) No. of Table 4. In steps 17 to 24, glass articles were manufactured by subjecting the treated glass to a chemical strengthening process, a surface layer etching process, and a water treatment process in this order. In addition, No. In Nos. 17 to 24, the thickness of the processing glass after the surface layer etching step matches the thickness of the glass article.

(4) No. of Table 5. In Nos. 25 and 26, a glass article was manufactured by subjecting the treated glass to a thinning process, a chemical strengthening process, a surface layer etching process, and a water treatment process in this order. No. of Table 5 In Nos. 27 to 29, glass articles were manufactured by performing a chemical strengthening process, a surface layer etching process, and a water treatment process on the treated glass in this order. Furthermore, No. of Table 5. In Examples 27 to 29, a protective layer (PET film, PA film, PI coat) was laminated on one main surface of a glass article to produce a laminate. The PET and PA films were bonded to the glass article via a 5 μm thick pressure sensitive adhesive (PSA) sheet. The PI coat was formed by applying PI to the main surface of the glass article. In addition, No. In Nos. 25 to 29, the thickness of the treated glass after the surface layer etching step matches the thickness of the glass article.

(5) No. of Table 6. In No. 30 and No. 31, the treated glass was used as a glass article without being treated. No. of Table 6 In No. 32 and No. 33, a glass article was manufactured by performing a thinning process on the treated glass. No. of Table 6 In No. 34 and No. 35, a glass article was manufactured by performing a chemical strengthening process on the treated glass. No. of Table 6 In No. 36 and No. 37, a glass article was manufactured by performing a thinning process and a chemical strengthening process in this order. In other words, No. 6 in Table 6. In Nos. 30 to 33, the chemical strengthening process and water treatment process were not performed on the glass for treatment. No. of Table 6 In Nos. 34 to 37, the water treatment process was not performed on the treated glass. In addition, No. At 30, 31, 34, 35, the initial thickness of the processing glass matches the thickness of the glass article. No. 32, 33, 36, and 37, the thickness of the processing glass after the thinning process matches the thickness of the glass article.

(6) No. of Table 7. In Nos. 38 and 39, glass articles were manufactured by subjecting the treated glass to a chemical strengthening step and a surface layer etching step in this order. No. of Table 7 In Nos. 40 and 41, a glass article was manufactured by performing a thinning process, a chemical strengthening process, and a surface layer etching process on the treated glass in this order. In other words, No. 7 in Table 7. In Nos. 38 to 41, the water treatment process was not performed on the treated glass. In addition, No. In Nos. 38 to 41, the thickness of the treated glass after the surface layer etching step matches the thickness of the glass article.

(7) No. of Table 8. In Nos. 42 to 45, a chemical strengthening step, a surface layer etching step, and a water treatment step were performed on the treated glass in this order to produce glass articles. In addition, No. 42 to 45, the thickness of the processing glass after the surface layer etching process matches the thickness of the glass article. In addition, No. In Nos. 42 to 45, the glass for treatment is subjected to a water treatment process, but the water treatment time is less than 0.5 hours or more than 15 hours.

In some examples and comparative examples in which a chemical strengthening process was performed, the CS, DOC, and CT of the glass articles were measured. CS, DOC, and CT in Tables 1 to 8 are values measured for each glass article (sample) using a surface stress meter FSM-6000LE manufactured by Orihara Seisakusho.

<Pen drop test>
As shown in FIG. 9, in the pen drop test, the strength (pen drop strength) of the glass article 13 included in the measurement sample 12 was evaluated by dropping the pen tip of the ballpoint pen 18 onto the measurement sample 12.

No. In the pen drop tests related to Nos. 1 to 26 and 30 to 45, a glass article 13, a PSA sheet 14, a PET board 15, a PSA sheet 16, and an SUS board 17 were laminated in this order as the measurement sample 12. On the other hand, No. In the pen drop tests related to Nos. 27 to 29, a protective layer (PET film, PA film, PI coat) was further provided on the top surface of the glass article 13 in the measurement sample 12 described above. In other words, No. In the pen drop tests related to Nos. 1 to 26 and 30 to 45, the pen tip of the ballpoint pen 18 was in direct contact with the glass article 13, and no. In the pen drop tests related to Nos. 27 to 29, the pen tip of the ballpoint pen 18 comes into direct contact with the protective layer.

The planar dimensions of the glass article 13, PSA sheets 14 and 16, PET board 15, and protective layer were each 50 mm x 50 mm. The dimensions of the SUS plate 17 in plan view were 55 mm x 55 mm. The thickness of the glass article 13 and the protective layer were as shown in Tables 2-8. The thickness of the PSA sheets 14 and 16 was 50 μm. The thickness of the PET board 15 was 125 μm. The thickness of the SUS plate 17 was 3 mm.

In the pen drop test, No. Five measurement samples 12 according to Nos. 1 to 45 are prepared, and the tip of the ballpoint pen 18 is dropped into the center of each measurement sample 12. At this time, the ballpoint pen 18 is dropped to the measurement sample 12 through the inner hole of the guide tube 19 held vertically so that the pen tip of the ballpoint pen 18 falls perpendicularly to the measurement sample 12. The ballpoint pen 18 is Orange EG0.7 manufactured by BIC, and has a ball diameter of 0.7 mm and a mass of 5.7 g. The height of the tip of the pen before dropping with reference to the top surface of the measurement sample 12 was defined as a falling height H, and the initial value was set to 1 cm, and the pen was dropped. If the glass article 13 included in the measurement sample 12 was not damaged by the drop of the ballpoint pen 18, the height was raised by 1 cm and the glass article 13 was dropped again. In this way, trials of increasing the drop height H and dropping are repeated until the glass article 13 included in the measurement sample 12 is broken. Then, the 60% failure height and the maximum failure height were determined as the pen drop strength. The 60% failure height is the falling height H when the glass articles 13 included in three measurement samples 12 among the five measurement samples 12 are broken. The maximum breakage height is the fall height H when all the glass articles 13 included in the five measurement samples 12 are broken.

According to the results of the pen drop test mentioned above, the examples (No. 1 to 29) in which a proper water treatment process was carried out either did not carry out a water treatment process at all, or did not carry out a proper water treatment process. It was confirmed that the fracture height was improved by 60% compared to the comparative examples (Nos. 30 to 45).

<Bending fracture test>
As shown in FIG. 10, in the bending fracture test, a measurement sample 20 made of a glass article is sandwiched between two plate-shaped bodies 21, and the strength ( Two-point bending strength) was evaluated. The two-point bending strength is No. Glass articles 2, 10, 18, 30, 34, and 38 were evaluated, and 30 measurement samples 20 corresponding to these glass articles were prepared. The dimensions of the measurement sample 20 in plan view were 140 mm x 70 mm. The thickness of the measurement sample 20 is as shown in Tables 2 to 8. 2, 10, 30, and 34, it was 50 μm, and No. In Nos. 18 and 38, the thickness was 47 μm. Then, the measurement sample 20 was placed between the plate-like bodies 21 so as to be bent in a U-shape along the long side (140 mm side).

The two-point bending strength was calculated from the following formula (4) using the distance D between the two plate-shaped bodies 21 when the glass article 20 was broken by pressing and bending. Then, the median value, maximum value, and minimum value were determined as the two-point bending strength. The median value of the two-point bending strength is the median value when the two-point bending strength data of 30 measurement samples are arranged in ascending order. The maximum value of the two-point bending strength is the maximum value of the two-point bending strengths of the 30 measurement samples. The minimum value of the two-point bending strength is the minimum value of the two-point bending strengths of the 30 measurement samples.
σ=1.198[E×t/(D−t)] (4)
However, in the formula, σ represents the two-point bending strength [MPa], E represents the Young's modulus [MPa] of the glass article, and t represents the thickness [mm] of the glass article.

According to the results of the bending fracture test mentioned above, chemically strengthened glass articles (No. 10, 18, 34, 38) have higher two-point bending strength than non-chemically strengthened glass articles (No. 2, 30). was confirmed to improve. In particular, it was confirmed that the two-point bending strength was significantly improved in the glass articles (Nos. 18 and 38) in which the surface layer etching process was performed after chemical strengthening. Therefore, from the viewpoint of improving both the pen drop strength and the two-point bending strength of the glass article, it is found that it is preferable to perform the chemical strengthening process and then perform an appropriate water treatment process.

The glass article of the present invention can be used, for example, as a cover glass for smartphones, mobile phones, tablet computers, personal computers, digital cameras, touch panel displays, and other display devices, in-vehicle display devices, in-vehicle panels, and the like.

1 Glass article 2 Compressive stress layer 3 Tensile stress layer 4 Container 5 Treated water 6 Processing glass 7 Support stand 8 Constant temperature device 9 Laminated body 10a Protective layer 10b Reinforcement layer 11 Adhesive layer 12 Measurement sample 13 Glass article 14 PSA sheet 15 PET board 16 PSA sheet 17 SUS plate 18 Ballpoint pen 19 Guide tube 20 Measurement sample (glass article)
21 Plate body

Claims (14)

1. a preparation step of preparing a processing glass made of alkali aluminosilicate glass containing an alkali metal oxide as a glass composition;
   A method for manufacturing a glass article, comprising a water treatment step of bringing the glass for treatment into contact with treated water for 0.5 hours or more and less than 15 hours.
2. The method for manufacturing a glass article according to claim 1, wherein in the water treatment step, the glass for treatment is immersed in the treatment water at a temperature of 46 to 100°C.
3. The method for manufacturing a glass article according to claim 1, wherein in the water treatment step, the glass for treatment is immersed in the treatment water at a temperature of 100° C. or higher under a pressurized atmosphere.
4. The method for manufacturing a glass article according to any one of claims 1 to 3, wherein in the water treatment step, the treated water has an electrical conductivity of 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 for treatment to within the thickness range by etching before the water treatment step.
7. 6. The method for manufacturing a glass article according to claim 5, wherein the processing glass is preformed within the thickness range by an overflow down-draw method.
8. Any one of claims 1 to 7, further comprising, before the water treatment step, a chemical strengthening step of bringing the glass for treatment into contact with an alkali metal nitrate to form a compressive stress layer having a maximum compressive stress of 100 MPa or more on the surface. A method for producing a glass article as described in Section 1.
9. The 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 treatment glass and the treated water is 0.5 to 10 hours. manufacturing method.
10. The glass for processing has a glass composition including, in mol%, SiO 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 0-10%,
    The method for manufacturing 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. The glass article according to any one of claims 8 to 10, further comprising a surface layer etching step of etching the processing glass in a shallower range than the compressive stress layer after the chemical strengthening step and before the water treatment step. manufacturing method.
12. A plate-shaped or sheet-shaped glass article with a thickness of 0.005 to 0.1 mm,
    A glass article having a 60% fracture height of 5 cm or more in a pen drop test in which a 5.7 g ballpoint pen with a spherical tip with a diameter of 0.7 mm is dropped onto the main surface.
13. The glass article according to claim 12, comprising a compressive stress layer having a maximum compressive stress of 100 MPa or more on the surface.
14. The glass article according to claim 12 or 13,
    A laminate comprising a protective layer or a reinforcing layer laminated on at least one main surface of the glass article.

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