JP5874803B2 - Manufacturing method of glass for touch panel - Google Patents

Description

  The present invention relates to a method for manufacturing glass for a touch panel, and specifically relates to a method for manufacturing glass for a touch panel mounted on a mobile phone, a digital camera, a PDA (portable terminal), a notebook PC, a pointing device, or a car navigation system.

  Devices such as mobile phones, digital cameras, and PDAs are widely used. In recent years, a type in which a touch panel is mounted on these devices has become widespread.

  Glass is used for the touch panel in order to protect the display and sensor part in the touch panel. Glass for touch panels generally has (1) high mechanical strength, (2) a high Young's modulus so that it is difficult to bend when pressing the surface with a pen or finger, etc. (3) a large amount at low cost Characteristics such as being able to be supplied are required. In addition, there are a resistance film type, a capacitance type, and the like as a touch panel type. Since the latter method can detect two or more points, various operation methods can be realized (see, for example, Patent Document 1).

JP-A-9-237158

  As described above, since the capacitive touch panel can detect two or more points, various operation methods can be realized. However, when a conventional capacitive touch panel is slid between two or more points with a finger etc., the finger etc. is likely to get caught on the glass surface, the operation feeling is not appropriate, and malfunctions such as erroneous operation are likely to occur. It was. Under such circumstances, a technique for improving the operability of the touch panel has become important.

  Further, when the touch panel is operated, the glass surface is often rubbed with a finger, a pen, or the like, so that the glass surface is easily damaged and the mechanical strength is likely to be lowered.

  Then, this invention makes it a technical subject to improve the surface of a glass, to improve the operativity of a touch panel, and to raise the mechanical strength of glass further.

  As a result of various investigations, the present inventors found that the reason that fingers and the like are easily caught on the glass surface is that the glass surface is too smooth, and if the glass surface is roughened and predetermined irregularities are formed, The present inventors have found that a technical problem can be solved and propose as the present invention. That is, the manufacturing method of the glass for touch panels of this invention is characterized by including the roughening process which makes the surface roughness Ra of all or one part of the glass surface 3-50000 mm. In addition, although the manufacturing method of the glass for touchscreens of this invention preferably roughens the whole glass surface, the surface equivalent to the operation surface of a touchscreen should just be roughened practically. Further, it is possible to roughen only an arbitrary portion by masking the surface of the glass substrate. Here, “surface roughness Ra” refers to a value measured by a method based on JIS B0601: 2001.

  The manufacturing method of the glass for touchscreens of this invention has a roughening process which makes the surface roughness Ra of all or one part of the glass surface 3-50000 mm. When the surface roughness Ra of the glass surface is 3 to 50000 mm, when two or more points are slid with a finger or the like, the finger or the like is hardly caught on the glass surface, and the operability of the touch panel is improved.

  2ndly, the manufacturing method of the glass for touchscreens of this invention is a process in which a roughening process is a process of immersing glass in an etching liquid. In this way, the glass surface can be appropriately roughened, and scratches present on the glass surface can be reduced, so that the mechanical strength of the glass can be maintained in the roughening step.

Third, in the method for producing a glass for a touch panel according to the present invention, the etching solution is one or two selected from the group consisting of HF, HCl, H ₂ SO ₄ , HNO ₃ , NH ₄ F, NaOH, and NH ₄ HF _2. It is characterized by including the above. If these etching liquids are used, the reactivity with glass becomes appropriate, so that the surface roughness Ra of the glass surface is easily made 3 to 50000 mm.

  4thly, the manufacturing method of the glass for touchscreens of this invention is that a roughening process is a sandblasting process. In this way, the glass surface of a large area can be uniformly roughened in a short time.

  Fifth, the method for manufacturing a glass for a touch panel according to the present invention is characterized by executing a step of immersing the glass in an etching solution after the sandblasting step. In this way, scratches generated in the sandblasting process can be reduced, and a situation where the mechanical strength of the glass is lowered can be prevented.

Sixth, glass for a touch panel of the present invention, glass is a glass composition including, in _{mass%, SiO 2 40~70%, Al} 2 O 3 1~30%, Li 2 O 0~10%, Na 2 O _{5~20%, K 2 O 0~10%} , characterized by containing MgO + CaO + SrO + BaO 0.1~15 %. If the glass composition range is regulated as described above, the reactivity with the etching solution can be increased, and a desired surface roughness can be easily obtained. Moreover, if the glass composition range is regulated as described above, the ion exchange performance can be enhanced.

  Seventh, the method for manufacturing a glass for a touch panel according to the present invention further includes a chemical strengthening step of forming a compressive stress layer in the vicinity of the glass surface. If an uneven shape is formed on the glass surface, stress concentrates on the uneven portion, and the mechanical strength of the glass tends to decrease. However, if a compressive stress layer is formed in the vicinity of the glass surface (preferably, a compressive stress layer is formed deeper than the uneven portion), the mechanical strength of the glass can be increased.

The chemical strengthening step is a step of ion exchange at a temperature below the glass strain point to introduce alkali ions having a large ion radius on the glass surface. If a compressive stress layer is formed on the glass in the chemical strengthening step, the mechanical strength of the glass can be increased. In addition, ion exchange conditions are not specifically limited, What is necessary is just to determine in consideration of the viscosity characteristic etc. of glass. In particular, when the Na component in the glass composition is ion-exchanged with K ions in the KNO ₃ molten salt, a compressive stress layer can be efficiently formed on the glass surface. In addition, unlike the physical strengthening process such as the air cooling strengthening method, the chemical strengthening process does not easily break the glass even if the glass is cut after the chemical strengthening process.

  Eighth, the method for producing a glass for a touch panel according to the present invention is characterized in that the chemical strengthening step is a step of setting a compressive stress value of the compressive stress layer to 200 MPa or more and a thickness of the compressive stress layer to 10 μm or more. . Here, the “compressive stress value of the compressive stress layer” and “thickness of the compressive stress layer” can be calculated by observing the number of interference fringes and their intervals with a surface stress meter.

  Ninthly, the manufacturing method of the glass for touchscreens of this invention is characterized by a chemical strengthening process being performed after a roughening process. If it does in this way, the probability that glass will be damaged by the crack which arose on the glass surface in the roughening process can be made low, and the mechanical strength of glass can be raised.

  Tenth, the glass for a touch panel of the present invention is characterized in that the surface roughness Ra of the whole or part of the glass surface is 3 to 50000 mm. When the surface roughness Ra of the glass surface is 3 to 50000 mm, when two or more points are slid with a finger or the like, the finger or the like is hardly caught on the glass surface, and the operability of the touch panel is improved.

Eleventh, the glass for a touch panel of the present invention has, as a glass composition, mass%, SiO ₂ 40 to 70%, Al ₂ O ₃ 1 to 30%, Li ₂ O 0 to 10%, Na ₂ O 5 to 5%. _{20%, K 2 O 0~10%} , characterized by containing MgO + CaO + SrO + BaO 0.1~15 %.

  Twelfth, the glass for touch panel of the present invention has a compressive stress layer formed near the glass surface, the compressive stress value of the compressive stress layer is 200 MPa or more, and the thickness of the compressive stress layer is 10 μm or more. Features.

  According to the method for manufacturing a glass for a touch panel of the present invention, an appropriate friction coefficient can be imparted to the glass surface by a roughening step, and when two or more points are slid with a finger or the like, an appropriate operational feeling is obtained. Can be obtained. Moreover, in the manufacturing method of the glass for touchscreens of this invention, when a chemical strengthening process is further included, the mechanical strength of glass can be raised and the breakage | damage etc. of glass can be prevented.

  The manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Ra of all or one part of the glass surface 3-50000 mm. If the surface roughness Ra is smaller than 3 mm, the friction coefficient of the glass surface becomes too large, and it becomes difficult for the finger or the like to slip. In consideration of sliding of fingers, the surface roughness Ra is preferably 50 mm or more, 100 mm or more, 500 mm or more, 1000 mm or more, 2000 mm or more, 5000 mm or more, 6000 mm or more, 7000 mm or more, particularly 8000 mm or more. On the other hand, when the surface roughness Ra is larger than 50000 mm, a rough feeling is generated when the glass surface is touched with a finger or the like. Considering the feeling of roughness, the surface roughness Ra is preferably 40000 mm or less, 30000 mm or less, 20000 mm or less, 18000 mm or less, particularly 16000 mm or less.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rq of all or one part of the glass surface 3-50000cm. If the surface roughness Rq is smaller than 3 mm, the friction coefficient of the glass surface becomes too large, and it becomes difficult for a finger or the like to slip. On the other hand, when the surface roughness Rq is larger than 50000 mm, a rough feeling is generated. The lower limit value of Rq is preferably at least 100, 1000, 3000, 5000, and 7000, and the upper limit is 50,000, 45,000, 40,000, 350,000, and 30000.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rz of all or one part of the glass surface 5 to 200000 mm. If the surface roughness Rz is less than 5 mm, the friction coefficient of the glass surface becomes too large, and it becomes difficult for a finger or the like to slip. On the other hand, when the surface roughness Rz is larger than 200000 mm, a rough feeling is generated. Preferred lower limit values of Rz are 100 to 500, 1000 to 10,000, 25,000 to 30000, 40000 to 40000, and upper limits are 200000 to 1800, 16000 to 120,000 and 100000 to 100000. is there.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rt of all or one part of the glass surface 10-250,000 mm. If the surface roughness Rt is less than 10 mm, the coefficient of friction on the glass surface becomes too large, and fingers and the like are difficult to slip. On the other hand, when the surface roughness Rt is larger than 250,000 mm, a rough feeling is generated. Preferred lower limit values of Rt are not less than 100, 500, 1000, 10,000, 25,000, 30000, 40000, and 50000, and upper limits are 200000 and less, 18000 and less, 160000 and less, 120,000 and less, 100000 and less. is there.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes surface roughness Rp of all or one part of the glass surface 3-100,000 ha. As a result of various studies, the present inventors have found that the crest height of the irregularities on the glass surface affects the operational feeling. If the surface roughness Rp is smaller than 3 mm, the friction coefficient of the glass surface becomes too large, and it becomes difficult for a finger or the like to slip. On the other hand, when the surface roughness Rp is larger than 100,000, a rough feeling is generated. Preferred lower limit values of Rp are 100 to 500, 1000 to 10,000 and 20,000, and the upper limit is 80,000, 70,000, 60000, 50,000 and 40000.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rv of all or one part of the glass surface 3-100,000 ha. As a result of various studies, the present inventors have found that the uneven depth of the glass surface affects the operational feeling. If the surface roughness Rv is smaller than 3 mm, the friction coefficient of the glass surface becomes too large, and it becomes difficult for the finger or the like to slip. On the other hand, when the surface roughness Rv is larger than 100,000, the feeling of roughness is generated or the strength is easily lowered. Preferred lower limit values of Rv are 100 to 500, 1,000 to 1,000, 2000 to 10,000, 15,000 to 20,000, and upper limits are 100,000 to 90,000, 70000 to 60000, and 50,000 to 50,000.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rsm of all or one part of the glass surface 150 micrometers or less. As a result of various studies, the present inventors have found that in addition to the size of the irregularities on the glass surface, the interval between the irregularities also affects the operational feeling. When the surface roughness Rsm is larger than 150 μm, it is difficult to smoothly slide the glass surface with a finger or the like, and a rough feeling tends to occur. Therefore, the surface roughness Rsm is preferably 130 μm or less, 110 μm or less, 100 μm or less, 90 μm or less, 85 μm or less, 80 μm or less, particularly 70 μm or less. On the other hand, if the surface roughness Rsm becomes too small, a finger or the like will be caught. Therefore, the surface roughness Rsm is preferably 5 μm or more, 10 μm or more, 20 μm or more, 30 μm or more, particularly 40 μm or more.

  It is preferable that the manufacturing method of the glass for touchscreens of this invention includes the roughening process which makes the surface roughness Rku of all or one part of the glass surface 30 or less. As a result of various studies, the present inventors have found that the degree of sharpness of the unevenness affects the operational feeling in addition to the size of the unevenness on the glass surface. When the surface roughness Rku is larger than 30, a rough feeling tends to occur when the glass surface is traced with a finger or the like, and the strength may be easily lowered. Therefore, the surface roughness Rku is preferably 20 or less, 10 or less, 5 or less, 4 or less, 3.5 or less, particularly 3.2 or less. On the other hand, if the surface roughness Rku is too small, the finger will feel caught. Therefore, the surface roughness Rku is preferably 1 or more, 1.5 or more, particularly 2 or more.

In the method for producing glass for a touch panel of the present invention, the roughening step is preferably a step of immersing the glass in an etching solution, and the etching solution is HF, HCl, H ₂ SO ₄ , HNO ₃ , NH ₄ F. One or two or more selected from the group of NaOH, NH ₄ HF ₂ are preferably contained, and a mixed solution of HF + NH ₄ F or a mixed solution of NH ₄ F + NH ₄ HF ₂ is particularly preferable. These etchants have good reactivity with glass, and if these etchants are used, reactants are uniformly generated on the glass surface, and the surface roughness of the glass surface can be in an appropriate range. it can. These etching solutions are preferably used at a temperature of 10 to 40 ° C. (preferably 15 to 35 ° C., more preferably 20 to 30 ° C.). When etching is performed at a temperature lower than 10 ° C., the reaction rate between the glass and the etchant becomes too slow, and the glass production efficiency is lowered. Further, if etching is performed at a temperature higher than 40 ° C., the etching solution is likely to volatilize, which may cause a problem in terms of safety and environment.

  In the method for producing glass for a touch panel of the present invention, the roughening step is preferably a sand blasting step. In this way, the glass surface of a large area can be uniformly roughened in a short time. The particle size of the blasting material used in the sand blasting process is preferably # 220 to # 4000, # 300 to # 2000, # 400 to # 1500, particularly # 400 to # 1200. When the particle size of the blast material is smaller than # 220, a rough feeling tends to occur when the glass surface is touched with a finger or the like. Further, if the particle size of the blast material is smaller than # 220, large cracks are likely to occur on the glass surface, and thus the mechanical strength of the glass tends to decrease. On the other hand, if the particle size of the blasting material is larger than # 4000, the friction coefficient of the glass surface increases, and the finger or the like becomes difficult to slip. The sand blasting process is a process in which a blasting material is collided with the glass surface to roughen the surface, so that the glass surface is likely to be damaged. Due to this, the mechanical strength of the glass may decrease. In such a case, the sandblasted surface is immersed in an etching solution to reduce the generated scratches, and the mechanical strength of the glass decreases. It is preferable to prevent such a situation. As the etchant, the above etchant (preferably an etchant containing HF) is suitable.

  In the method for producing glass for a touch panel according to the present invention, the roughening step may be a polishing step by # 220 to # 4000 (preferably # 300 to # 2000, # 400 to # 1500, particularly # 400 to # 1200). Good. Further, it is preferable to immerse the polished glass surface in an etching solution to reduce the generated scratches and prevent a situation where the mechanical strength of the glass is lowered. As the etchant, the above etchant (preferably an etchant containing HF) is suitable.

  In the method for producing glass for a touch panel of the present invention, the glass to be roughened is prepared by mixing glass raw materials so as to have a desired glass composition, and the obtained glass batch is put into a continuous melting furnace at 1500 to 1600 ° C. After being melted by heating, it can be clarified and then supplied to a molding apparatus to mold and gradually cool the molten glass.

  As a glass forming method, various methods such as a down draw method (overflow down draw method, slot down method, redraw method, etc.), a float method, a roll-out method, and a press method can be employed.

If the surface quality of the glass before the roughening step is high, the glass surface can be uniformly roughened, so that a desired surface roughness can be easily obtained. From such a viewpoint, the overflow down draw method is preferable as the glass forming method. In the case of the overflow down draw method, the surface to be the surface of the glass is not in contact with the bowl-shaped refractory and is molded in a free surface state, so that the surface quality of the glass can be improved without being polished. Here, the overflow down draw method is a method in which the molten glass overflows from both sides of the heat-resistant bowl-shaped structure, and the overflowed molten glass joins at the lower end of the bowl-shaped structure and is stretched downward to form a substrate shape. This is a method of forming glass. The structure and material of the bowl-shaped structure are not particularly limited as long as desired dimensions and surface quality can be realized. Moreover, the method of applying force to the glass when stretched downward is not particularly limited. For example, a method may be adopted in which a heat-resistant roll having a sufficiently large width is rotated and stretched in contact with glass, or a plurality of pairs of heat-resistant rolls are contacted only near the end face of the glass. It is also possible to adopt a method of stretching by stretching. If the liquidus temperature is 1200 ° C. or less and the liquidus viscosity is 10 ^4.0 dPa · s or more, substrate-shaped glass can be produced by the overflow down draw method.

It is preferable that the manufacturing method of the glass for touchscreens of this invention further includes the chemical strengthening process which makes the compressive-stress value of the compressive-stress layer of the glass surface 200 MPa or more, and makes the thickness of a compressive-stress layer 10 micrometers or more. The compressive stress value of the compressive stress layer is preferably 300 MPa or more, 400 MPa or more, 500 MPa or more, 600 MPa or more, and particularly preferably 700 MPa or more. The larger the compressive stress value of the compressive stress layer, the better the mechanical strength of the glass. On the other hand, if an extremely large compressive stress layer is formed on the glass surface, microcracks are likely to occur on the glass surface, and conversely, the mechanical strength of the glass may be reduced. Moreover, if the compressive stress value of the compressive stress layer is too large, the tensile stress inherent in the glass may become extremely large. Considering the above points, the compressive stress value of the compressive stress layer is preferably 1500 MPa or less. Note that if the content of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , MgO, ZnO, SnO _{2 in} the glass composition is increased or the content of SrO, BaO is decreased, the compressive stress value of the compressive stress layer increases. Become. Further, if the ion exchange time is shortened or the ion exchange temperature is lowered, the compressive stress value of the compressive stress layer is increased.

In the method for producing glass for a touch panel of the present invention, when desired irregularities are formed on the glass surface in a sandblasting process or the like, there is a possibility that fine microcracks may be formed on the glass surface. In order to prevent breakage starting from such cracks, the thickness of the compressive stress layer is preferably 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, and particularly preferably 60 μm or more. Moreover, the situation where the glass surface of the glass for touch panels is rubbed with a pen, a finger, etc. as mentioned above is assumed. If the thickness of the compressive stress layer is small, the mechanical strength of the glass may be significantly reduced due to scratches caused by a pen or a finger. Therefore, if the thickness of the compressive stress layer is increased, the glass is difficult to break even if the glass surface is deeply scratched. On the other hand, if the thickness of the compressive stress layer is extremely large, the glass becomes difficult to cut or the tensile stress inside the glass becomes extremely high, and conversely, the glass may be damaged. Therefore, the thickness of the compressive stress layer is preferably 500 μm or less, 100 μm or less, 90 μm or less, and particularly preferably 80 μm or less. If the content of Al ₂ O ₃ , K ₂ O, P ₂ O ₅ , TiO ₂ , ZrO _{2 in} the glass composition is increased or the content of SrO, BaO is decreased, the thickness of the compressive stress layer is increased. Become. Moreover, if the ion exchange time is lengthened or the ion exchange temperature is increased, the thickness of the compressive stress layer is increased.

  The manufacturing method of the glass for touchscreens of this invention can include the process of reheating glass and carrying out a softening deformation | transformation after a roughening process. Moreover, you may perform a roughening process after the process of reheating glass and softening and deforming. If it does in this way, it will become easy to transform glass into a complicated shape.

  The reason for limiting the glass composition range of the glass as described above in the method for producing glass for a touch panel of the present invention will be described below.

SiO ₂ is a component that forms a network of glass, and its content is 40 to 70%, preferably 50 to 67%, 52 to 65%, 55 to 63%, particularly 56 to 60%. If the content of SiO ₂ is too large, it becomes difficult to melt and mold the glass, or the thermal expansion coefficient becomes too small to match the thermal expansion coefficient of the surrounding materials. On the other hand, when the content of SiO ₂ is too small, vitrification becomes difficult, the thermal expansion coefficient becomes too large, and the thermal shock resistance tends to be lowered.

Al ₂ O ₃ is a component that enhances ion exchange performance, and also has an effect of increasing the strain point and Young's modulus, and its content is 1 to 30%. When the content of Al ₂ O ₃ is too large, devitrification crystal glass becomes easily precipitated, it becomes difficult to mold the glass by an overflow down draw method or the like. If the content of Al ₂ O ₃ is too large, the thermal expansion coefficient becomes too small, or is difficult to match the thermal expansion coefficient with those of peripheral materials becomes high temperature viscosity, it becomes difficult to melt. On the other hand, when the content of Al ₂ O ₃ is too small, if the chemical strengthening occurs a possibility can not be sufficiently exhibited ion exchange performance. If the content of Al ₂ O ₃ is too small, the etching, the desired reaction product is hardly generated, it becomes difficult to improve the glass surface. From the above viewpoint, the preferable upper limit range of Al ₂ O ₃ is 20% or less, 19% or less, 18% or less, 17% or less, particularly less than 16.5%. Further, a preferable lower limit range of Al ₂ O ₃ is 2% or more, 4% or more, 5% or more, 10% or more, 11% or more, particularly 13% or more.

Li ₂ O is an ion-exchange component, a component that lowers the high-temperature viscosity, improves meltability and moldability, and further improves the Young's modulus. Li ₂ O has a high effect of increasing the compressive stress value among alkali metal oxides. However, if the content of Li ₂ O is too large, the liquid phase viscosity is lowered and the glass is easily devitrified, the thermal expansion coefficient is too large, the thermal shock resistance is lowered, and the heat of the surrounding materials is decreased. It becomes difficult to match the expansion coefficient. Furthermore, when the content of Li ₂ O is too large, the low-temperature viscosity is excessively decreased, stress relaxation is likely to occur, and conversely, the compressive stress value may be decreased. Therefore, the content of Li ₂ O is 0 to 5%, preferably 0 to 3.5%, 0 to 3%, 0 to 2%, 0 to 1%, 0 to 0.5%, particularly 0 to 0%. It is 0.1%, and it is most preferable not to contain substantially, that is, 0 to less than 0.01%.

Na ₂ O is an ion exchange component, a component that lowers the high temperature viscosity, improves meltability and moldability, and further improves devitrification resistance. The content of Na ₂ O is 5 to 20%, but more preferable content is 7 to 18%, 7 to 16%, 8 to 16%, 9 to 16%, 10 to 16%, particularly 11 to 15%. %. When the content of Na 2 _O is too large, the thermal expansion coefficient becomes too large, thermal shock resistance becomes difficult to match the thermal expansion coefficient with those of reduced or peripheral materials. Further, when the content of Na 2 _O is too large, or too low the strain point, it is impaired balance of components glass composition, devitrification resistance conversely tends to decrease. On the other hand, if too small content of Na 2 _O, lowered the melting property, too coefficient of thermal expansion is reduced, decreases the ion exchange performance.

K ₂ O has an effect of promoting ion exchange, and has a high effect of increasing the thickness of the compressive stress layer among alkali metal oxides. K ₂ O is a component that lowers the high-temperature viscosity and improves meltability and moldability, and also improves devitrification resistance. The content of K ₂ O is 0 to 15%. If the content of K ₂ O is too large, the thermal expansion coefficient becomes too large, the thermal shock resistance decreases, it becomes difficult to match the thermal expansion coefficient of the surrounding materials, the strain point decreases too much, the glass composition However, the devitrification resistance tends to decrease. Therefore, the preferable upper limit range of K ₂ O is 10% or less, 9% or less, 8% or less, 6% or less, particularly 5% or less. Further, a preferable lower limit range of K ₂ O is 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, particularly 2% or more.

If the total amount of alkali metal oxides (Li ₂ O, Na ₂ O, K ₂ O) is too large, the glass tends to devitrify, the thermal expansion coefficient becomes too large, and the thermal shock resistance decreases. It becomes difficult to match the thermal expansion coefficient of the surrounding material. If the total amount of the alkali metal oxide is too large, the strain point may be too low and it may be difficult to increase the compressive stress value, and the viscosity near the liquidus temperature may be lowered, resulting in a high liquidus viscosity. It may be difficult to ensure. Therefore, the total amount of alkali metal oxides is preferably 22% or less. On the other hand, if the total amount of the alkali metal oxide is too small, the ion exchange performance and meltability may be lowered. Therefore, the total amount of alkali metal oxides is preferably 8% or more, 10% or more, 13% or more, and particularly preferably 15% or more.

  MgO + CaO + SrO + BaO is a component that increases the reactivity with the etching solution. When there is too much MgO + CaO + SrO + BaO, a density and a thermal expansion coefficient will become high too much, devitrification resistance will fall, or ion exchange performance will fall. Therefore, the content of MgO + CaO + SrO + BaO is 0.1 to 15%, preferably 1 to 15%, 2 to 13%, 3 to 12%, 3 to 10%, particularly 3.5 to 8%.

  MgO is a component that lowers the viscosity at high temperature, increases meltability and moldability, and increases the strain point and Young's modulus. Among alkaline earth metal oxides, MgO is a component that has a high effect of improving ion exchange performance. is there. Moreover, when MgO is added to the glass composition, a desired reaction product is easily generated during etching, and the glass surface is easily improved. However, when there is too much content of MgO, a density and a thermal expansion coefficient will become high, or it will become easy to devitrify glass. Therefore, the content of MgO is 0-6%, 0.1-6%, 0.5-6%, 1-6%, 1.5-6%, 1.8-5%, 1.8-4 %, Particularly 1.8 to 3.5% is preferred.

  CaO is a component that lowers the high-temperature viscosity of glass, increases meltability and formability, and increases the strain point and Young's modulus. Among alkaline earth metal oxides, CaO has a high effect of improving ion exchange performance. It is an ingredient. Moreover, when CaO is added to the glass composition, a desired reaction product is easily generated during etching, and the glass surface is easily improved. However, when there is too much content of CaO, a density and a thermal expansion coefficient may become high too much, glass may become easy to devitrify, and also ion exchange performance may fall. Therefore, the content of CaO is 0 to 12%, 0.1 to 12%, 0.3 to 12%, 0.3 to 9%, 1 to 9%, 1.5 to 8%, 1.5 to 6 %, Particularly 1.5 to 4.5% is preferred.

  SrO and BaO are components that lower the high-temperature viscosity, increase the meltability and moldability, and increase the strain point and Young's modulus, and their content is preferably 0 to 10%. If the content of SrO or BaO is too large, the ion exchange performance tends to decrease, the density and the thermal expansion coefficient become too high, and the glass tends to devitrify. The SrO content is preferably 5% or less, 3% or less, 1% or less, 0.5% or less, 0.2% or less, and particularly preferably 0.1% or less. The BaO content is preferably 5% or less, 3% or less, 1% or less, 0.8% or less, 0.5% or less, 0.2% or less, and particularly preferably 0.1% or less.

  Although a glass composition may be comprised only with the said component, another component can be added to 30% in the range which does not impair the characteristic of glass largely.

  ZnO is a component that enhances the ion exchange performance. In particular, it is a component that has a large effect of increasing the compressive stress value, and is a component that has the effect of reducing the high temperature viscosity without reducing the low temperature viscosity. When there is too much content, glass will phase-divide, devitrification resistance will fall, or a density will become high too much. Therefore, the ZnO content is preferably 8% or less, 6% or less, 4% or less, and particularly preferably 3% or less.

ZrO ₂ has the effect of remarkably improving ion exchange performance, increasing Young's modulus and strain point, and lowering high temperature viscosity. Moreover, since ZrO ₂ has an effect of increasing the viscosity in the vicinity of the liquid phase viscosity, when a predetermined amount is added to the glass composition, the ion exchange performance and the liquid phase viscosity can be improved at the same time. However, when the content of ZrO ₂ is too high, there are cases where the devitrification resistance is extremely lowered. Therefore, the content of ZrO ₂ is preferably 0 to 10%, 0.0001 to 10%, 0.1 to 9%, 0.5 to 7%, 1 to 5%, particularly preferably 2.5 to 5%.

B ₂ O ₃ has the effect of lowering the liquidus temperature, the high temperature viscosity and the density, and has the effect of improving the ion exchange performance, particularly the compressive stress value. Burns occur on the surface, the water resistance decreases, the liquid phase viscosity decreases, and the thickness of the compressive stress layer tends to decrease. Therefore, the content of B ₂ O ₃ is preferably 0 to 6%, 0 to 4%, particularly preferably 0 to 3%.

TiO ₂ has the effect of improving the ion exchange performance and the effect of reducing the high temperature viscosity. However, when the content of TiO ₂ is too large, or glass is colored, lowered resistance to devitrification, the density is high. Therefore, the content of TiO ₂ is 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 2% or less, 0.7% or less, 0.5% or less, 0.1% or less, In particular, 0.01% or less is preferable.

P ₂ O ₅ is a component that enhances ion exchange performance, and in particular, a component that increases the thickness of the compressive stress layer. However, when the content of P ₂ O ₅ is too large, glass or phase separation, the water resistance and devitrification resistance tends to decrease. Therefore, the content of P ₂ O ₅ is preferably 8% or less, 5% or less, 4% or less, 3% or less, and particularly preferably 2% or less.

As a fining agent, 0.001 to 3% of one or more selected from the group of As ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , CeO ₂ , F, SO ₃ , and Cl can be added. However, As ₂ O ₃ and Sb ₂ O ₃ have been pointed out to have environmental problems, it is preferable to limit their contents to less than 0.1%, particularly less than 0.01%. Further, CeO ₂ is a component that lowers the transmittance, so it is preferable to limit its content to less than 0.1%, particularly less than 0.01%. Furthermore, F may reduce the low-temperature viscosity and may cause a decrease in the compressive stress value. Therefore, the content is preferably limited to less than 0.1%, particularly less than 0.01%. Considering the above points, the fining agent is preferably one or more selected from the group of SnO ₂ , SO ₃ , and Cl, and the content of these is 0.001 to 3%, 0.001 in total. -1%, 0.01-0.5%, more preferably 0.05-0.4%.

Rare earth oxides such as Nb ₂ O ₅ and La ₂ O ₃ are components that increase the Young's modulus. However, the rare earth oxide is expensive in the raw material itself, and when added in a large amount during the glass composition, the devitrification resistance decreases. Accordingly, the rare earth oxide content is desirably 3% or less, 2% or less, 1% or less, 0.5% or less, and particularly 0.1% or less.

  Transition metal elements such as Co and Ni that strongly color the glass reduce the transmittance, so if the content is too much, the transmittance is significantly reduced and used when the touch panel requires visibility It becomes difficult to do. In such a case, it is preferable to adjust the amount of raw material or cullet used, and to make its content 0.5% or less, 0.1% or less, particularly 0.05% or less.

  Since substances such as Pb and Bi have been pointed out as environmental problems, it is preferable to limit the content to less than 0.1%.

In the manufacturing method of the glass for touchscreens of this invention, the density of the glass to be used is 2.8 g / cm < ³ > or less, 2.7 g / cm < ³ > or less, 2.6 g / cm < ³ > or less, especially 2.55 g / cm < ³ > or less. preferable. The smaller the density, the lighter the glass. Here, “density” refers to a value measured by the well-known Archimedes method. In addition, increase the content of SiO ₂ , P ₂ O ₅ , B ₂ O _{3 in} the glass composition, or decrease the content of alkali metal oxide, alkaline earth metal oxide, ZnO, ZrO ₂ , TiO _2. For example, the density decreases.

In the method for producing glass for a touch panel of the present invention, the strain point of the glass used is preferably 500 ° C. or more, 510 ° C. or more, and particularly preferably 520 ° C. or more. As the strain point is higher, the heat resistance is improved, the glass is less likely to be deformed in the heat treatment step, and the compressive stress layer is less likely to disappear. Also, if the strain point is high, stress relaxation is difficult to occur during the ion exchange treatment, and a high compressive stress value is easily obtained. Here, the “strain point” refers to a value measured based on the method of ASTM C336. In addition, if the content of the alkaline earth metal oxide, Al ₂ O ₃ , ZrO ₂ , and P ₂ O _{5 in} the glass composition is increased or the content of the alkali metal oxide is decreased, the strain point is increased.

In the method for producing glass for a touch panel of the present invention, the softening point of the glass used is preferably 850 ° C. or lower, 830 ° C. or lower, 800 ° C. or lower, and particularly preferably 775 ° C. or lower. When the softening point is higher than 850 ° C., it is difficult to reheat the glass and soften and deform it into a desired shape. Here, the “softening point” refers to a value measured based on the method of ASTM C338. Note that if the content of alkali metal oxide, alkaline earth metal oxide, or B ₂ O _{3 in} the glass composition is increased, or the content of Al ₂ O ₃ or ZrO ₂ is decreased, the softening point is lowered.

In the method for producing glass for a touch panel of the present invention, the temperature at which the glass used has a high temperature viscosity of 10 ^2.5 dPa · s is 1600 ° C., 1580 ° C., 1450 ° C., 1430 ° C., 1420 ° C., particularly 1400 ° C. The following is preferred. The temperature at the high temperature viscosity of 10 ^2.5 dPa · s corresponds to the melting temperature of the glass, and the lower the temperature at the high temperature viscosity of 10 ^2.5 dPa · s, the more the glass can be melted. Therefore, the lower the temperature at a high temperature viscosity of 10 ^2.5 dPa · s, the less the burden on glass manufacturing equipment such as a melting kiln, and the higher the bubble quality of the glass. As a result, the glass is manufactured at low cost. Can do. Here, “temperature at a high temperature viscosity of 10 ^2.5 dPa · s” refers to a value measured by a platinum ball pulling method. If the content of alkali metal oxide, alkaline earth metal oxide, ZnO, B ₂ O ₃ , TiO _{2 in} the glass composition is increased or the content of SiO ₂ , Al ₂ O ₃ is decreased, the temperature is increased. The temperature at a viscosity of 10 ^2.5 dPa · s decreases.

  In the method for producing glass for a touch panel of the present invention, the Young's modulus of the glass used is preferably 70 GPa or more, 73 GPa or more, and particularly preferably 75 GPa or more. As the Young's modulus is higher, when the glass surface of the touch panel is pressed with a pen or a finger, the amount of deformation of the glass becomes smaller, damage to the display or sensor inside the touch panel is reduced, and the operability of the touch panel is improved. Here, “Young's modulus” refers to a value measured by a bending resonance method.

In the method for manufacturing a glass for a touch panel of the present invention, the thermal expansion coefficient of the glass used is ^{70~110 × 10 -7 / ℃, 75~110} × 10 -7 / ℃, 80~110 × 10 -7 / ℃, especially 85-110 * 10 < ^-7 > / degreeC is preferable. If the thermal expansion coefficient is regulated within the above range, it becomes easy to match the thermal expansion coefficient of a member such as a metal wiring used for the touch panel, and peeling of these members can be prevented. Here, the “thermal expansion coefficient” refers to a value obtained by measuring an average value in a temperature range of 30 to 380 ° C. using a dilatometer. If the content of alkali metal oxides and alkaline earth metal oxides in the glass composition is increased, the coefficient of thermal expansion increases, and conversely, the alkali metal oxides and alkaline earth metal oxides in the glass composition increase. If the content is reduced, the thermal expansion coefficient is lowered.

In the method for producing glass for a touch panel of the present invention, the liquidus temperature of the glass used is 1200 ° C. or lower, 1050 ° C. or lower, 1030 ° C. or lower, 1010 ° C. or lower, 1000 ° C. or lower, 950 ° C. or lower, 900 ° C. or lower, particularly 870 ° C. The following is preferred. The lower the liquidus temperature, the better the devitrification resistance and the better the moldability. Here, “liquid phase temperature” refers to a temperature gradient furnace in which glass is crushed, passed through a standard sieve 30 mesh (a sieve opening of 500 μm), and glass powder remaining in a 50 mesh (a sieve opening of 300 μm) is placed in a platinum boat. It is held for 24 hours and refers to a value obtained by measuring the temperature at which crystals precipitate. If the content of Na ₂ O, K ₂ O, B ₂ O _{3 in} the glass composition is increased or the content of Al ₂ O ₃ , Li ₂ O, MgO, ZnO, TiO ₂ , ZrO ₂ is decreased. The liquidus temperature decreases.

In the method for producing glass for a touch panel of the present invention, the liquid phase viscosity of the glass to be used is 10 ^4.0 dPa · s or more, 10 ^4.3 dPa · s or more, 10 ^4.5 dPa · s or more, 10 ^5.0 dPa · s or higher, 10 ^5.4 dPa · s or higher, 10 ^5.8 dPa. s or more, ^106.0 dPa · s or more, and particularly preferably 10 ^6.2 dPa · s or more. The higher the liquidus viscosity, the better the devitrification resistance and the better the moldability. Here, “liquid phase viscosity” refers to a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method. If the content of Na ₂ O, K ₂ O in the glass composition is increased, or the content of Al ₂ O ₃ , Li ₂ O, MgO, ZnO, TiO ₂ , ZrO ₂ is decreased, the liquid phase viscosity is increased. To rise.

  The glass for a touch panel of the present invention is characterized in that the surface roughness Ra of the whole or part of the glass surface is 3 to 50000 mm. Here, since the technical characteristics (surface roughness, glass composition, glass characteristics, etc.) of the glass for touch panel of the present invention have already been described in the explanation column of the method for manufacturing glass for touch panel of the present invention, For convenience, the description is omitted.

  The glass for a touch panel of the present invention preferably has a substrate shape (including not only a flat plate shape but also a softened and deformed curved shape). If it does in this way, it can use for a substrate for touch panels. The thickness of the glass substrate is 3.0 mm or less, 2.0 mm or less, 1.8 mm or less, 1.7 mm or less, 1.5 mm or less, 1.0 mm or less, 0.7 mm or less, 0.5 mm or less, particularly 0 .3 mm or less is preferable. The smaller the plate thickness of the glass substrate, the lighter the glass substrate. In addition, when the glass substrate is chemically strengthened, the glass substrate is hardly broken even if the thickness of the glass substrate is reduced. In addition, when a molten glass is shape | molded by the overflow downdraw method, the glass substrate which is unpolished and has favorable surface quality can be obtained.

  Hereinafter, the present invention will be described based on examples.

  Table 1 shows the glass composition and characteristics of the glass used in the experiment.

  Glasses described in Table 1 were produced as follows. First, after preparing a glass raw material so that it might become the glass composition in a table | surface, the glass batch obtained in the platinum pot was thrown in and it melted at 1580 degreeC for 8 hours. Next, molten glass was poured out on the carbon plate and formed into a substrate shape. Various characteristics were evaluated about the obtained glass.

  The density is a value measured by a well-known Archimedes method.

  The strain point Ps and the annealing point Ta are values measured based on the method of ASTM C336.

  The softening point Ts is a value measured based on the method of ASTM C338.

The temperature at a high temperature viscosity of 10 ^4.0 dPa · s, 10 ^3.0 dPa · s, and 10 ^2.5 dPa · s is a value measured by a platinum ball pulling method.

  The Young's modulus is a value measured by a bending resonance method.

  The thermal expansion coefficient α is a value obtained by measuring an average value in a temperature range of 30 to 380 ° C. using a dilatometer.

  The liquid phase temperature TL is obtained by crushing glass, passing through a standard sieve 30 mesh (a sieve opening of 500 μm), and putting the glass powder remaining in 50 mesh (a sieve opening of 300 μm) into a platinum boat and placing it in a temperature gradient furnace for 24 hours. This is a value obtained by measuring the temperature at which crystals are deposited.

  The liquid phase viscosity log ηTL is a value obtained by measuring the viscosity of the glass at the liquid phase temperature by a platinum ball pulling method.

Followed by chemically strengthened by immersing 8 hours KNO ₃ molten salt glass of 460 ° C. according to Table 1. Next, after cleaning the glass surface after chemical strengthening, the number of interference fringes on the glass surface and the interval between them are observed using a surface stress meter (FSM-6000 manufactured by Toshiba Corporation), and the compression of the compression stress layer is observed. Stress values and thicknesses were calculated. In the calculation, the refractive index of the glass was 1.52, and the optical elastic constant was 28 [(nm / cm) / MPa]. Note that the glass composition of the untempered glass and the tempered glass are not substantially different as the whole glass, although the glass composition is microscopically different in the surface layer of the glass. Therefore, characteristic values such as density and viscosity are not substantially different between untempered glass and tempered glass.

  About the substrate-shaped glass (unreinforced) produced by the method described in the column of Example 1, the glass surface was surface-treated under various conditions, and the surface roughness (Ra, Rq, Rz, Rt, Rp, Rv, Rsm, Rku) and operational feeling were evaluated. The results are shown in Table 2.

The experiment was performed in the order of a sandblasting step, a step of immersing in an etching solution, and a chemical strengthening step. The sand blast treatment was performed by spraying a blast material (4 kg of Al ₂ O ₃ dispersed in 20 L of water) onto the glass surface at 2 MPa. Moreover, KNO ₃ molten salt was used in the ion exchange.

  Surface roughness Ra, Rq, Rz, Rt, Rp, Rv, Rsm, and Rku are values measured by a method based on JIS B0601: 2001.

  The feeling of operation is to trace the glass surface with your finger, ◎ if it slides well, `` ○ '' if it slides, `` △ '' if it slides slightly, but `` × '' if your finger is caught evaluated. In addition, the surface roughness Ra of the glass surface before performing surface treatment such as etching was 2 mm, and the evaluation was “×”.

  As is apparent from Table 2, the glass having a predetermined surface roughness had a good evaluation of operational feeling.

For substrate-shaped glass (thickness 1.0 mm, unstrengthened) produced by the method described in Example 1, after surface treatment was performed according to the procedure in the table, AG-10kNIS (manufactured by Shimadzu Corporation) was used. A biaxial bending test was performed to evaluate the in-plane strength. The results are shown in Table 3. The sand blasting process was performed by spraying a blast material (4 kg of Al ₂ O ₃ dispersed in 20 L of H ₂ O) onto the glass surface at 2 MPa. Moreover, KNO ₃ molten salt was used in the ion exchange.

  The feeling of operation is to trace the glass surface with your finger, ◎ if it slides well, `` ○ '' if it slides, `` △ '' if it slides slightly, but `` × '' if your finger is caught evaluated. In addition, the surface roughness Ra of the glass surface before performing surface treatment such as etching was 2 mm, and the evaluation was “×”.

As apparent from Table 3, the glass having a predetermined surface roughness was excellent in operational feeling and high in mechanical strength.

Claims (4)

All or part of the surface roughness Rsm of the glass surface Ri 5~100μm der, and glass for a touch panel, wherein the surface roughness Rku is 30 or less.   2. The glass for a touch panel according to claim 1, wherein a surface roughness Ra of the whole or a part of the glass surface is 3 to 50000 mm. As a glass composition, in _{mass%, SiO 2 40~70%, Al} 2 O 3 1~30%, Li 2 O 0~10%, Na 2 O 8 ~20%, K 2 O 0~10%, MgO + CaO + SrO + BaO 0 The glass for a touch panel according to claim 1, wherein the glass is contained in an amount of 0.1 to 15%. A compressive stress layer is formed near the glass surface,
The glass for a touch panel according to any one of claims 1 to 3, wherein a compressive stress value of the compressive stress layer is 200 MPa or more and a thickness of the compressive stress layer is 10 µm or more.