KR20180055711A - Glass for chemical strengthening and chemically strengthened glass - Google Patents

Abstract

An object of the present invention is to obtain a chemically strengthened glass having a high CS value through one chemical strengthening treatment, and to provide a glass for chemical strengthening which can suppress defects of an edge portion when chamfering the chemically strengthened glass. The present invention relates to a specific composition range, and relates to a glass for chemical strengthening having a main surface and a back surface opposing the main surface, wherein a tin content in the back surface is larger than a tin content in the main surface. A hydrogen concentration in a depth of 1-2 μm in a sheet thickness direction from a surface of the main surface is gradually decreasing.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass reinforced glass,

The present invention relates to a chemical strengthening glass and a chemically strengthened glass (hereinafter also referred to as chemical strengthening glass).

BACKGROUND ART In recent years, chemical tempered glass has been used as a cover glass in a flat panel display device (hereinafter referred to as a device or the like) such as a portable telephone or a portable information terminal (PDA). The chemical tempered glass is required to have a strength that is mounted on a device or the like and is not broken even when the device is dropped.

As an index indicating the strength of the chemically tempered glass, there is a compressive stress value (CS value). It is required that the chemical strengthening glass is obtained by chemical strengthening treatment once, and a chemical strengthening glass having a high CS value (for example, 1000 MPa or more) is obtained. On the other hand, when the chemical tempered glass is mounted on an apparatus or the like, the edge portion of the end face is chamfered to improve the sense of touch.

Here, in Patent Document 1, it is disclosed that chemical strengthening glass is subjected to chemical strengthening treatment twice to obtain chemical strengthened glass having CS value exceeding 1000 MPa. Further, in Patent Document 2, it is disclosed that the H concentration distribution of the glass affects the warp of the chemically tempered glass.

International Publication No. 2012/043482 International Publication No. 2013/005588

However, none of the above literatures discloses a chemical strengthening glass having a high CS value by one chemical strengthening treatment, and a chemical strengthening glass capable of suppressing the edge defect at the time of chamfering the chemical strengthening glass, And does not have a preview.

It is an object of the present invention to provide a chemical strengthening glass having a high CS value by one chemical strengthening treatment and capable of suppressing the edge defects at the time of chamfering the chemical strengthening glass.

The inventors of the present invention have found that a chemical strengthening glass having a specific glass composition and having a gradual decrease in hydrogen concentration at a depth of 1 to 2 탆 in the thickness direction from the surface of the main surface in the depth direction, And completed the present invention.

That is, the present invention relates to the following <1> to <8>.

&Lt; 1 > As a mole percentage based on oxide,

SiO ₂ : 60 to 67%

Al ₂ O ₃ : 9 to 13.5%

Na ₂ O: 13.5 to 18.5%

0.1 to 3% of K ₂ O,

MgO: 6 to 10.5% and

TiO ₂ : more than 0% and not more than 5%

Wherein the tin content of the back surface is larger than the tin content of the main surface and the hydrogen concentration at a depth of 1 to 2 占 퐉 in the plate thickness direction from the surface of the main surface gradually decreases in the depth direction Wherein the chemical strengthening glass is a glass.

&Lt; 2 > The chemical strengthening glass according to < 1 >, wherein the hydrogen concentration at a depth of 1 to 2 mu m in the thickness direction direction from the surface of the back surface gradually decreases in the depth direction.

<3> The hydrogen concentration at a depth of 1 to 10 μm in the plate thickness direction from the surface of the main surface is lower than the hydrogen concentration at a depth of 1 to 10 μm in the plate thickness direction from the surface of the back surface. &Lt; / RTI >

&Lt; ⁴ > The chemical strengthening glass according to any one of < 1 > to < 3 &gt;, wherein the temperature T4 at which the glass has a viscosity of 10 ⁴ dPa · s is at most 1255 ° C.

<5> the chemical strengthened glass as described for the ZrO ₂ to the mole percent of the oxide-based display of any of <1> to <4> containing 0.11% or less than 4.0% one.

&Lt; 6 > A chemically tempered glass in which the chemical strengthening glass according to any one of < 1 > to < 5 >

<7> The chemical tempered glass according to <6>, wherein the surface compressive stress (CS) is 900 MPa or more.

<8> The chemical tempered glass according to <6> or <7>, wherein the compressive stress layer depth (DOL) is 30 μm or more.

The chemical strengthening glass of the present invention is a glass capable of obtaining a chemically reinforced glass having a high CS value by a single chemical strengthening treatment and suppressing the edge defects at the time of chamfering the chemical tempered glass.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a profile of hydrogen concentration on a top surface (main surface) and a bottom surface (back surface) of the present invention and a conventional product. The ordinate indicates the hydrogen concentration (atoms / cm ³ ), and the abscissa indicates the depth in the plate thickness direction (mu m) from the surface.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below, but the present invention is not limited to the following embodiments, and can be arbitrarily modified within the range not departing from the gist of the present invention. In the present specification, "%" means "mol%", and "to" means lower than or equal to the upper limit.

<Glass for chemical strengthening>

The glass for chemical strengthening according to the present invention (hereinafter sometimes simply referred to as &quot; glass &quot;) is represented by a molar percentage based on the oxide. The glass contains 60 to 67% of SiO ₂ , 9 to 13.5% of Al ₂ O ₃ , ₂ O: 13.5 to 18.5%, K ₂ O: 0.1 to 3%, MgO: 6 to 10.5%, and TiO ₂ : 0 to 5%.

Hereinafter, each component in the glass composition will be described.

SiO ₂ is a main component of glass. In addition, it is a component that reduces the generation of cracks when scratches (indentations) are formed on the glass surface, or reduces the destruction rate when indentations occur after chemical strengthening. SiO ₂ is also a component for enhancing the acid resistance of glass and reducing the amount of sludge in the etching treatment (enhancing the moisture resistance).

On the other hand, if the content of SiO ₂ is too large, the viscosity at high temperature becomes too high and productivity is low. Therefore, the content of SiO ₂ is 60 to 67%, preferably 62% or more, more preferably 63% or more, further preferably 66% or less and more preferably 65% or less.

The more Al ₂ O _3, the higher the CS during the chemical strengthening treatment, while the lower the DOL. Therefore, the content of Al ₂ O ₃ is 9 to 13.5%, preferably 9.5% or more, more preferably 10% or more, further preferably 12% or less, and more preferably 11.5% or less.

Na ₂ O is an essential component for forming a surface compressive stress layer by ion exchange and has an effect of increasing the DOL. Further, it is a component that improves the solubility and moldability of the glass by lowering the melting temperature and the melting temperature of the glass. Na ₂ O is a component that increases non-crosslinked oxygen, and when the content of Na ₂ O is large, fluctuation of chemical strengthening characteristics when the moisture content in the glass changes is small.

The greater the number of Na ₂ O, the larger the DOL during the chemical strengthening treatment and the lower the CS. In addition, from the viewpoint of DUV resistance, the lower the non-crosslinked oxygen, the better, because the inclusion of Na ₂ O tends to lower the DUV resistance.

The DUV resistance is a property to prevent a decrease in transmittance in a specific wavelength region with respect to an ultraviolet ray in a short wavelength region called Deep UV (DUV).

Therefore, the content of Na ₂ O is 13.5 to 18.5%, preferably 14.5% or more, more preferably 15% or more, further preferably 17.5% or less and more preferably 16.5% or less.

K ₂ O has an effect of increasing the ion exchange rate to increase the DOL, lower the melting temperature of the glass, and increase the non-crosslinked oxygen. It is also possible to avoid an increase in the change in the surface compressive stress due to the NaNO ₃ concentration in the potassium nitrate molten salt used in the chemical strengthening treatment. Furthermore, a small amount of K ₂ O has an effect of suppressing the amount of tin from the bottom surface when the glass sheet is formed by the float method. Therefore, it is preferable that the small amount of K ₂ O is contained when forming by the float method. In order to exhibit the above effect, the content of K ₂ O in the glass of the present invention is 0.1% or more, preferably 0.3% or more, and more preferably 0.4% or more.

On the other hand, if K ₂ O is too much, CS is lowered. In addition, the content of K ₂ O tends to lower the DUV resistance. From these viewpoints, the content of K ₂ O is 3% or less, preferably 2% or less, more preferably 1.3% or less, more preferably 1% or less, still more preferably 0.95% or less.

MgO stabilizes the glass and improves the solubility, and by adding it, the content of the alkali metal is lowered and the increase of the thermal expansion coefficient (CTE) is suppressed. In order to achieve the above effect, the content of MgO in the glass of the present invention is 6% or more, preferably 7% or more, and more preferably 7.5% or more. On the other hand, in order to increase the DOL, the content of MgO is 10.5% or less, preferably 9.5% or less, and more preferably 9% or less.

TiO ₂ is a component that improves DUV resistance. On the other hand, if the amount of TiO ₂ is too large, the DOL decreases. Therefore, the content of TiO ₂ is more than 0% and not more than 5%, preferably not less than 0.01%, more preferably not less than 0.03%, more preferably not more than 3%, more preferably not more than 1% , More preferably 0.4% or less, and particularly preferably 0.3% or less.

ZrO ₂ is a component that imparts excellent DUV resistance, improves chemical durability, increases CS at chemical strengthening, and improves Vickers hardness after chemical strengthening.

The glass according to the present invention preferably contains both TiO ₂ and ZrO _{2. When} ZrO ₂ is contained, the content is preferably 0.1% or more, more preferably 0.11% or more, still more preferably 0.12% or more , And 0.13% or more is more preferable.

On the other hand, the content of ZrO ₂ is preferably 4% or less, more preferably 3% or less, still more preferably 2% or less, from the viewpoint of suppressing the devitrification at the time of glass production and preventing the decrease of DOL at the time of chemical strengthening , More preferably 1.5% or less, and particularly preferably 1% or less.

Further, the glass for enhanced chemical according to the present invention, Na ₂ O, K ₂ O, Al ₂ O _3, ZrO _2, with respect to the content represented by mol percentage shown in the oxide basis of _{TiO 2, [(Na 2 O} + K ₂ O x 5) / (Al ₂ O ₃ + ZrO ₂ + TiO ₂ x 10)] is 2.55 or less.

As described above, Na ₂ O and K ₂ O are components that increase the DOL while lowering CS and DUV resistance. In addition, a component to lower the temperature T2, the viscosity of glass is ² to 10 dPa · s and a temperature T4, the viscosity of the glass is ⁴ to 10 dPa · s.

Al ₂ O ₃ , ZrO ₂ and TiO ₂ can increase the CS and DUV resistance while lowering the DOL. Al ₂ O ₃ is a component that increases the temperature T 2 and the temperature T 4, and if it is too large, the viscosity at high temperature increases and the productivity of the glass decreases.

That is, from the balance of CS, DOL, acid resistance and productivity, the value represented by [(Na ₂ O + K ₂ O 5) / (Al ₂ O ₃ + ZrO ₂ + TiO ₂ × 10)] is preferably 2.55 or less More preferably 2.0 or less, still more preferably 1.9 or less, still more preferably 1.8 or less, still more preferably 1.75 or less, and particularly preferably 1.71 or less. Further, it is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 1.0 or more.

In the present invention, in particular in order to increase the CS, also in order to improve the acid resistance, Al ₂ O _3, with respect to the content represented by mol percentage shown in the K ₂ O oxide basis, Al ₂ O ₃ / K ₂ O Is more than 10, is satisfied. Al ₂ O ₃ / K ₂ O is more preferably at least 10.3, more preferably at least 10.5, even more preferably at least 11.5, even more preferably at least 12.5, particularly preferably at least 14.0, and most preferably at least 15.0 Do.

In _{addition, MgO, Na 2 O, K} 2 O, ZrO 2 , and with respect to the content represented by mol percentage shown in the oxide basis of _{TiO 2, [(MgO / 2} + Na 2 O + K 2 O × 2) / (TiO ₂ + ZrO ₂ )] of 53 to 140 is satisfied because it is possible to reduce the amount of sludge to be described later (to improve the anti-vacancy property). _{[(MgO / 2 + Na 2} O + K 2 O × 2) / (TiO 2 + ZrO 2)] for which the value is 130 and below are more preferable, and 125 or less, more preferably, less is more preferable than 120 represented by the Do. It is more preferably 55 or more, and more preferably 60 or more.

The composition of the glass can be measured simply by fluorescence X-ray method. By wet analysis, the glass composition can be measured more accurately.

Further, other components that can be contained in the glass according to the present invention are shown below.

B ₂ O ₃ is a component that promotes the melting of the glass raw material and improves the brittleness and weather resistance of the glass.

When B ₂ O ₃ is not contained, the content of the B ₂ O ₃ is 1% or more, so that the destruction rate when the Vickers indentation occurs after the chemical strengthening can be reduced or the melting property at a high temperature is improved. The content of B ₂ O ₃ is preferably not more than 15%, more preferably not more than 10%, further preferably not more than 7.5%, in order to avoid generation of ream due to volatilization and erosion of wall walls , More preferably not more than 5%, and particularly preferably not more than 3%.

P ₂ O ₅ is a component which improves the damage resistance without impairing ion exchange performance. The content of P ₂ O ₅ is not required to be contained. When the content of P ₂ O ₅ is contained, the content thereof is preferably at least 1%, more preferably at least 2%, further preferably at least 2.5%, whereby the crack initiation load (CIL) Glass can be obtained. By setting the content of P ₂ O ₅ to 10% or less, more preferably 5% or less, and further preferably 3% or less, glass having particularly excellent acid resistance can be obtained.

CaO is a component for stabilizing glass and may be contained in order to prevent delamination due to the presence of MgO and also to improve the solubility while suppressing the rise of CTE. The content of CaO is preferably 0 to 5%, more preferably 0 to 3%, still more preferably 0 to 1%. When the content of CaO is 5% or less, a sufficient ion exchange rate is obtained, and a desired DOL is obtained. When the ion exchange performance in the chemical strengthening is specifically to be improved, the CaO is preferably less than 1%, more preferably not more than 0.5%.

CaO / MgO is preferably 0.5 or less from the viewpoints of improving the ion exchange performance in chemical strengthening and increasing the transmittance of the glass plate.

In addition, SO ₃ , chloride, fluoride and the like may be appropriately contained in the range of 0 to 1% as the glass fining agent.

SrO may be contained as occasion demands, but it may lower the rate of ion exchange compared to MgO and CaO. Therefore, it is preferable that SrO is substantially not contained, or even if it is contained, the content thereof is preferably 3% or less.

In the present specification, substantially no impurities are those which do not contain any inevitable impurities. For example, the amount is preferably less than 0.05%, more preferably less than 0.01%.

Since BaO has the greatest effect of lowering the ion exchange rate among the alkaline earth metal oxides, BaO is not substantially contained or, if contained, the content thereof is preferably 3% or less, more preferably 1% or less, 0.5% or less is more preferable.

When SrO or BaO is contained, the total content thereof is preferably 3% or less, more preferably 1% or less, still more preferably 0.5% or less, further preferably 0.3% or less.

In the case of containing at least one of CaO, SrO and BaO, the total content of the three components is preferably 3% or less, more preferably 3% or less. When the total amount is 3% or less, a decrease in ion exchange rate can be avoided. , More preferably not more than 1%, further preferably not more than 0.5%, even more preferably less than 0.3%.

Li ₂ O is preferably a component substantially free from stress because the strain point and the low-temperature viscosity are excessively lowered to facilitate stress relaxation and consequently the stress value of the compressive stress layer is lowered.

In addition, Li ₂ O may be eluted into a molten salt such as KNO ₃ at the time of chemical strengthening treatment, but when the chemical strengthening treatment is carried out using a molten salt containing Li, the surface compressive stress remarkably decreases. Therefore, Li ₂ O is preferably substantially free from this viewpoint.

SnO ₂ is a component that enhances DUV resistance. SnO ₂ may not be included. When it is included, the content thereof is preferably 0.001% or more, more preferably 0.005% or more, still more preferably 0.01% or more, and particularly preferably 0.02% or more. On the other hand, SnO ₂ is preferably 1% or less, more preferably 0.7% or less, still more preferably 0.5% or less, still more preferably 0.3% or less, and most preferably 0.1% Is particularly preferable.

CeO ₂ is a component that improves DUV resistance, but on the other hand it greatly degrades the resistance to the solarisation. The content of CeO ₂ is preferably less than 0.1%, more preferably less than 0.05%, still more preferably less than 0.01%, most preferably substantially not.

As ₂ O ₃ is a component that makes DUV resistance more excellent and promotes refinement of the glass batch, but has a high environmental load. Therefore, it is most preferable that As ₂ O ₃ is substantially not contained.

<Hydrogen concentration>

The glass according to the present invention is formed by a float method and has a bottom surface (back surface) that is in contact with molten metal (tin) at the time of molding and a top surface (main surface) opposite to the bottom surface. The tin content on the bottom surface is greater than the tin content on the top surface. The inventors of the present invention have found that the amount of defects of the edge portion generated by chamfering the float glass differs depending on the difference in hydrogen concentration between the top surface and the bottom surface.

In the production of glass by the float method, molten glass is continuously supplied from the upstream side to the surface of the molten metal stored in the float bath to draw the glass ribbon after molding from the downstream side end of the float bath while molding the glass ribbon , And slowly cooled in a standing cold bath (rare) to produce a plate glass.

In the production of glass by the float process, an apparatus of the type in which the flow path between the glass melting furnace and the float bath is narrowed is usually used. In this case, since it is necessary to expand the width of the glass in the float bath, a molten glass of a higher temperature is flowed to the surface of the molten metal to be molded, compared with the case of using another type of apparatus described later.

Due to the low dew point that the float bath, and the H ₂ O diffuses from the glass surface, the main surface (topmyeon) is from the H ₂ O diffuses into the atmosphere. Further, H ₂ O diffuses from the back surface (bottom surface) into the molten metal. Therefore, the float glass produced in this type of device has a lower hydrogen concentration on the surface side than in the glass interior. However, the slope of the hydrogen concentration at a depth of 1 to 2 占 퐉 in the plate thickness direction from the surface can be controlled by the production conditions.

The glass according to the present invention has a main surface and a back surface opposed to the main surface, the tin content of the back surface being larger than the tin content of the main surface, and the hydrogen concentration Is gradually reduced in the depth direction. It is also preferable that the hydrogen concentration at a depth of 1 to 2 占 퐉 in the plate thickness direction from the surface of the back surface is also gradually decreased in the depth direction.

Here, the phrase "the hydrogen concentration at a depth of 1 to 2 μm in the plate thickness direction from the surface is gradually decreased in the depth direction" can be obtained, for example, by secondary ion mass analysis Means that the measured hydrogen concentration is preferably 5 to 80% / 탆, more preferably 20 to 50% / 탆 in the depth direction at a depth of 1 to 2 탆 in the plate thickness direction from the surface.

Since the diffusion coefficient of H ₂ O is higher at higher temperatures, the diffusion amount of H ₂ O from the top surface in contact with the dew point is lower than the bottom surface of the float glass in contact with the molten metal at a lower temperature, The hydrogen concentration on the top surface becomes lower than the bottom surface of the float glass.

On the other hand, in the production of glass by the float method, a type of apparatus in which the flow path is not narrowed between the glass melting furnace and the float bath may be used. In the case of manufacturing in this type of apparatus, since it is not necessary to widen the glass in the float bath, a molten glass of a lower temperature is flowed into the molten metal at a higher temperature than that of the apparatus of the above-described type, and is molded.

Since the diffusion coefficient of H ₂ O is higher at higher temperatures, the temperature of the bottom surface may be higher than the top surface of the float glass. In this case, the diffusion amount of H ₂ O from the bottom surface is larger than that of the top surface The hydrogen concentration on the bottom surface becomes lower than the top surface of the float glass.

Therefore, in the glass produced by the float method, the hydrogen concentration of the top surface is lower than that of the bottom surface or the hydrogen concentration of the bottom surface is lower than that of the top surface due to the production conditions.

In the glass according to the present invention, it is preferable that the hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the main surface is lower than the hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the backface Do.

In order to reduce the amount of defects at the edge portion during chamfering of the chemically tempered glass, the glass according to the present invention is characterized in that the absolute value of the average hydrogen concentration ratio of the depth of 1 to 2 mu m in the thickness direction from the surface of the main surface and the back surface is 1 , The closer it is, the more preferable. Specifically, for example, an absolute value of the average hydrogen concentration ratio of 1 to 2 mu m in depth in the plate thickness direction from the surface of the main surface and the back surface, which is measured by secondary ion mass spectrometry according to the analytical conditions described later in Examples, It is preferably 0.4 to 1.6, more preferably 0.6 to 1.4.

The hydrogen concentration of the glass according to the present invention can be evaluated by the following H / Si value.

[Evaluation of hydrogen concentration by H / Si value]

By evaluating the hydrogen concentration by the H / Si value, the depth direction resolution of the SIMS (Secondary Ion Mass Spectrometry) profile and the repeat measurement accuracy are improved.

In the present invention, since it is difficult to measure the hydrogen concentration itself and the hydrogen concentration ratio itself with high accuracy, it is difficult to measure the H / Si value proportional to the hydrogen concentration as a direct index of the hydrogen concentration, / The ratio of the bottom surface to the top surface of the Si value &quot; is used as a direct index of the hydrogen concentration ratio.

The ratio of the bottom surface to the top surface of the average H / Si value in the float glass can be measured by secondary ion mass spectrometry (SIMS analysis), for example, by the following procedures (I) and . In addition, the analysis conditions shown below are exemplary and should be appropriately changed depending on the measuring apparatus, the sample, and the like.

(I) Secondary ion mass spectrometry is performed on each of the top and bottom surfaces under the following analytical conditions to a depth of 10 mu m from the surface layer.

(Analysis condition)

Measuring device: secondary ion mass spectrometer with dual convergence mass spectrometer

Primary ion species: Cs ⁺

Primary acceleration voltage: 15.0 kV

Primary ion current: 100 nA

Primary angle of incidence (angle from the direction perpendicular to the surface of the sample): about 24.0 °

Raster size: 90 × 90 μm ²

Detection area: 30 占 퐉

Secondary ion polarity: minus

Use of gun for neutralization

Surface coating: material Pt, film thickness about 10 to 20 nm

As a secondary ion mass spectrometer having a dual-converging mass spectrometer, for example, IMS-7f manufactured by CAMECA may be mentioned.

(II) Calculate the ratio of the bottom surface to the top surface with respect to the average H / Si value up to a depth of 10 占 퐉 of the H / Si profile obtained by the secondary ion mass spectrometry in (I).

The glass according to the present invention preferably has an absolute value of the ratio of the bottom surface to the top surface to an average H / Si value at a depth of 1 to 2 m in the thickness direction from the surface of 0.4 to 1.6, more preferably 0.6 To 1.4.

<Chamfer processing and measurement>

The measurement of the amount of defects of the edge portion caused by chamfering and chamfering of glass is performed in the following procedure. A glass substrate having individual pieces of glass is prepared. The outer periphery of the glass substrate is subjected to a two-round chamfering process using an automatic glass grinder and a grinding stone. Subsequently, the distance between two points is measured using a microscope, and the number of chippings having a size of 20 mu m or more is counted.

<Solubility and moldability>

In the glass according to the present invention, the temperature T2, which is a reference example for melting the glass, that is, the temperature T2 at which the glass has a viscosity of 10 ² dPa 는 is preferably 1660 캜 or less, more preferably 1650 캜 or less, Is more preferable.

In the glass according to the present invention, the temperature T4 at which the viscosity of the glass becomes 10 ⁴ dPa 기준 is preferably 1255 캜 or lower, more preferably 1240 캜 or lower, and 1230 캜 or lower More preferably 1225 占 폚 or lower.

Further, the temperature T2 and the temperature T4 can be measured using a rotary viscometer.

<Amount of sludge>

For the purpose of adjusting the surface characteristics of the glass or the like, the glass may be subjected to an etching treatment, but when the glass is etched, sludge (residue) is generated. Here, since the sludge may affect the etchant life or the like, it is preferable from the viewpoint of productivity and the like that the sludge is small when the glass is etched. The analysis method of the sludge is shown below.

An etching solution is added to a glass plate to be a sample and stirred, and the glass is dissolved and allowed to stand. The resulting sludge is filtered through a filter paper and washed with water. The sludge is dried, weighed, and the sludge weight is calculated. The composition of the sludge can be analyzed by XRD and SEM-EDX.

The amount of sludge varies depending on the etching conditions. For example, a glass plate to be a sample is a 2.5 cm x 2.5 cm x 0.55 mm glass plate, and 50 mL of an etching solution containing 7 wt% HF and 20 wt% The amount of sludge in the case of etching for 3 minutes is preferably 0.66 g or less, more preferably 0.65 g or less, and most preferably 0.64 g or less, per 1 g of glass.

Examples of the components of the sludge include Na ₂ SiF ₆ , NaMgAlF ₆ , Na ₂ MgAlF ₇ , KNaSiF _6, and KMgAlF ₆ , although they vary depending on the glass composition.

<DUV Resistance>

In the present specification, the DUV resistance refers to a case of irradiating UV (DUV) with a wavelength of 100 to 280 nm, that is, a low-pressure mercury lamp having a dominant wavelength of 185 nm and 254 nm, an Xe gas excimer lamp having a dominant wavelength of 172 nm, an ArF excimer lamp having a dominant wavelength of 193 nm, Means that the decrease in the transmittance at a wavelength of 380 to 780 nm is suppressed when a KrF excimer lamp or the like having a main wavelength of 248 nm is irradiated.

The UV irradiation on the shorter wavelength side is generally used for UV cleaning treatment of the substrate, surface modification, UV sterilization treatment, and the like.

In the glass according to the present invention, when the transmittance in the wavelength range of 380 to 780 nm before UV irradiation on the short wavelength side is T0 and the transmittance in the wavelength region of 380 to 780 nm is T1 after irradiation , The DUV organic absorption? At each wavelength represented by the following formula is preferably 0.095 or less, more preferably 0.085 or less, and even more preferably 0.08 or less.

DELTA alpha = -ln (T1 / T0)

<Other characteristics, etc.>

It is preferable that the glass according to the present invention is formed of a glass plate, and the glass plate thickness (plate thickness) at that time is preferably from 0.1 to 3 mm, more preferably from 0.1 to 2.0 mm, even more preferably from 0.1 to 1.5 mm, More preferably 1.0 mm, and particularly preferably 0.1 mm to 0.9 mm.

The glass transition temperature (Tg) of the glass according to the present invention is preferably 550 DEG C or higher, more preferably 580 DEG C or higher, more preferably 600 DEG C or higher, still more preferably 620 DEG C or higher, desirable. The Tg of 550 DEG C or more is advantageous in terms of suppressing stress relaxation during chemical strengthening treatment and suppressing thermal bending.

The adjustment of Tg is possible by adjusting the total amount of SiO ₂ and Al ₂ O _{3 and} the amount of alkali metal oxide and alkaline earth oxide.

The average thermal expansion coefficient of the glass according to the present invention, α, in the temperature range of 50 to 350 ℃, preferably from 65 × 10 ^-7 to 110 × 10 ^-7 / K, and more preferably 70 × 10 ^-7 / K or more, more preferably 80 × 10 ^-7 / K or more, even more preferably 85 × 10 ^-7 / K or more, further preferably 100 × 10 ^-7 / K or less, ^-7 / K or less. The average thermal expansion coefficient? Is 65 × 10 ^-7 / K or more, which is advantageous in terms of the matching of thermal expansion coefficients with metals and other materials. The adjustment of the average thermal expansion coefficient can be made by adjusting the amounts of the alkali metal oxide and the alkaline earth oxide.

Density at room temperature of the glass in accordance with the present invention, preferably from 2.35 to 2.6g / cm ^3, and more preferably 2.38g / cm ^3, more preferably at least 2.40g / cm ^3, more preferably Cm &lt; ³ &gt; or less, and more preferably 2.50 g / cm &lt; ³ &gt; or less.

The Young's modulus E of the glass according to the present invention is preferably 60 GPa or more. When the Young's modulus E of the glass is 60 GPa or more, the glass has sufficient crack resistance and fracture strength. More preferably not less than 68 GPa, and even more preferably not less than 70 GPa.

The glass transition temperature of the present invention is preferably 0.28 or less. When the Poisson's ratio σ is 0.28 or less, the crack resistance of the glass becomes sufficient. More preferably 0.25 or less.

<Chemical tempered glass>

The chemical tempered glass of the present invention is chemically tempered glass in which the above-mentioned chemical tempering glass is chemically strengthened. In other words, it is a chemically tempered glass having the composition of the chemical strengthening glass of the present invention as a mother composition and having a compressive stress layer on its surface.

That is, the composition of the chemical tempered glass is the composition of the glass before chemical strengthening (glass for chemical strengthening). Here, the portion of the chemically tempered glass having a tensile stress (hereinafter also referred to as a tensile stress portion) is a portion not subjected to ion exchange. Since the tensile stress portion of the chemical tempered glass has the same composition as that of the glass for chemical strengthening, the composition of the tensile stress portion can be regarded as the parent composition.

The surface compression stress value CS is preferably 900 MPa or higher, more preferably 920 MPa or higher, even more preferably 950 MPa or higher, and more preferably 1000 MPa or higher, in view of preventing scratches on the surface of the chemically tempered glass and obtaining sufficient strength for practical use And even more preferably at least 1100 MPa. On the other hand, the CS is preferably 1400 MPa or less, more preferably 1300 MPa or less, more preferably 1280 MPa or less, in view of the possibility that the tensile stress value (CT) at the center of the glass becomes too large to be crushed when the glass breaks desirable.

Further, when the surface of the chemically tempered glass is scratched, the depth of the scratches may exceed the compressive stress layer depth (DOL) and the chemical tempered glass tends to be broken. Therefore, the DOL is preferably 30 m or more More preferably not less than 31 탆, more preferably not less than 32 탆, and even more preferably not less than 34 탆. On the other hand, the DOL is preferably 60 占 퐉 or less, more preferably 50 占 퐉 or less, because the tensile stress value (CT) at the center of the chemically tempered glass becomes too large and may be broken when the chemical tempered glass is destroyed.

Here, the values of CS and DOL can be measured by a surface stress meter. The CS and DOL of the chemically tempered glass can be appropriately adjusted by adjusting the processing conditions of the chemical strengthening treatment and the composition of the chemical strengthening glass.

<Production Method of Glass>

The method for producing a chemical strengthening glass according to the present invention is not particularly limited, and a method for molding a molten glass is not particularly limited. For example, a glass raw material is appropriately prepared and melted by heating at a temperature of about 1500 to 1700 占 폚, homogenized by defoaming, stirring, and the like, and then shaped into a plate shape by a known float method, down- Or cast to form a block shape, followed by slow cooling and cutting to a desired size to produce a glass plate. The surface of the glass plate may be treated with fluorine in place of or in addition to the polishing process. The float method or the down-draw method is preferable in view of stably producing the glass plate, and the float method is particularly preferable in view of producing a large-sized glass plate.

The glass plate of the present invention is a size of a display such as a tablet PC or a smart phone, a size of a decorative glass in a car, and a size of a window glass of a building or a house. Although the glass of the present invention is cut into a rectangular shape in general, it may be any other shape such as a circular shape or a polygonal shape, and includes glass subjected to perforated processing.

The glass of the present invention is preferably chemically strengthened. Before the chemical strengthening treatment, it is preferable to carry out mechanical working such as cutting, end face machining and drilling, depending on the application.

The chemical strengthening treatment is carried out, for example, by cutting the produced glass to a desired size to obtain a glass plate, preheating the glass plate to about 400 ° C, ion exchanging Na on the surface of the glass plate and K in the molten salt in the molten salt can do.

Further, after the ion exchange in a molten salt containing a specific salt, an acid treatment and an alkali treatment may be carried out to form a chemically strengthened glass plate having a higher strength.

Examples of the molten salt for carrying out the ion exchange treatment include alkali nitrate, alkali sulfate and alkali chloride salts such as potassium nitrate, potassium sulfate and potassium chloride. These molten salts may be used alone or in combination of plural kinds. Further, in order to adjust the chemical strengthening property, salts containing sodium may be mixed.

The adjustment of the CS of the chemically tempered glass can be made by adjusting the Na concentration, the strengthening time and the molten salt temperature in the molten potassium nitrate salt used for the ion exchange. In order to obtain higher CS, the Na concentration in the molten potassium nitrate salt is reduced.

The DOL can be adjusted by adjusting the Na concentration, the strengthening time and the molten salt temperature in the molten potassium nitrate salt used for the ion exchange. To obtain a higher DOL, the temperature of the molten salt is increased.

The chemically tempered glass can be cut after the chemical strengthening treatment. As the cutting method, scribing and braking using a conventional foil chip cutter can be applied, and cutting with a laser is also possible. In order to maintain the glass strength, chamfering of the cutting edge may be performed after cutting. The chamfer may be a mechanical grinding process or a treatment with a chemical liquid such as hydrofluoric acid.

The use of the glass of the present invention is not particularly limited. The chemically reinforced glass has high mechanical strength and is suitable for use in locations where impact due to falling or contact with other materials is expected.

Specifically, for example, a mobile phone (including a multifunctional information terminal such as a smart phone), a PHS, a PDA, a tablet type terminal, a notebook type personal computer, a game machine, a portable music / video player, , A cover glass for a display part such as a camera or a GPS, and a cover glass of a touch panel operation monitor of these devices, a cover glass of a cooker such as a microwave oven and an oven toaster, a top plate such as an electromagnetic cooker, A glass cover for a reading part such as a copying machine or a scanner, and the like.

In addition, for example, there are applications such as window glass for vehicles, ships and aircraft, decorative glass for automobiles, home or industrial lighting devices, signals, guide lights, cover glasses for electric bulletin boards, showcase and bulletproof glass. A solar cell protection cover glass, and a glass material for light focusing for increasing the power generation efficiency of a solar cell.

Further, for example, there can be mentioned various types of glass for mirror surfaces, furthermore, the base of an information storage medium such as a HDD, and the substrate of an information recording medium such as a CD, a DVD and a Blu-ray disc.

In addition, for example, there can be mentioned a use such as a water tank, a dish such as a dish or a cup, various cooking utensils such as a bottle or a cutting board, a cupboard, a shelf board of a refrigerator, and a building material such as a wall, a roof or a partition.

In addition to these applications, the chemically tempered glass produced by completing the chemical strengthening treatment is optimal as a glass material for displays assembled in various image display devices such as liquid crystal, plasma, and organic EL.

[Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Examples 1 to 5 are Examples, and Example 6 is Comparative Example. In addition, the values indicated in parentheses are calculated values, and the blank indicates that it is non-contained or unevaluated.

The raw materials were prepared so as to have the composition shown in Table 1 on a molar percentage basis on an oxide basis, put into a crucible made of platinum, put into a resistance heating type electric furnace at 1650 캜 for melting for 3 hours, homogenized and defoamed.

The obtained glass was introduced into a mold, held at a temperature of 680 캜 for 1 hour, and then cooled to room temperature at a rate of 1 캜 / minute to obtain a glass block. Subsequently, the glass block was cut, polished, and mirror-finished on both sides to obtain a glass having a predetermined size.

In addition, the glasses of Example 3 and Example 6 were prepared by the float method.

&Lt; T2, T4 >

The temperature T2 at which the viscosity of the glass was 10 ² dPa · s and the temperature T4 at 10 ⁴ dPa · s were measured using a rotary viscometer.

&Lt; Sludge amount, sludge component >

The glass was etched to measure the amount of sludge. Etching was performed by immersing the glass as a sample in a 2.5 cm x 2.5 cm x 0.55 mm glass plate at 50 占 폚 for 3 minutes at 50 占 폚 in an etching solution containing 7% by weight of HF and 20% by weight of HCl. The resulting sludge was filtered with a 5A filter paper, washed with water, and dried, and the weight of the sludge was measured. The amount of sludge was converted per 1 g of glass.

The components of the sludge were identified by XRD measurement. The detailed measurement conditions are as follows.

Optics: BB, incidence parallel slit: Soller slit 5 °, incidence slit: 1/3 °, light receiving parallel slit: Soller slit 5 °, Scan speed: 10 占 min., Sampling width: 0.02 占 Measurement range: 20 to 60 占 Analysis: PDXL (ver.2.0.3.0)

Table 2 shows the obtained T2, T4, sludge amount of the glass and main components of the sludge.

As shown in Table 1, the glass of Examples 1 to 5 was glass having a small amount of sludge at the time of etching as compared with the glass of Example 6.

<Chemical strengthening characteristics>

Further, a glass having a thickness of 0.55 mm was immersed in a molten potassium nitrate salt having a concentration of 100 wt% at a temperature of 425 DEG C for 6 hours to perform chemical strengthening treatment. The values of CS (MPa) and DOL (占 퐉) of the obtained chemically tempered glass plate were measured by a surface stress meter (Orihara Seisakusho). The results are shown in Table 1.

As shown in Table 1, when the glass was chemically strengthened under the same chemical strengthening conditions, the chemically tempered glass according to Examples 1 to 5 had a high CS as compared with the chemically tempered glass according to Example 6.

<DUV Resistance>

The transmittance of each glass was measured before DUV irradiation and after DUV irradiation. That is, each glass was heat-treated at (Tg + 50 deg. C) for 1 hour, slowly cooled to room temperature at 1 deg. C / min, and then polished so that the plate thickness became equal, Light having a main wavelength of 185 nm and 254 nm) was irradiated for 10 minutes from a position 5 cm above the glass plate, and then the transmittance at a wavelength of 380 nm was measured.

The illuminance at 254 nm of the glass plate at this time was 8 mW / cm ² (measurement by the illuminometer UV-M03A and the receiver UV-SD25-M10, manufactured by Oak Seisyakusho). The transmittance was measured by a spectrophotometer (trade name: U-4100) manufactured by Hitachi High-Technologies Corporation.

The transmittance at a wavelength of 380 nm before light irradiation is T0 and the transmittance at a wavelength of 380 nm after light irradiation is T1, the DUV organic absorption? Represented by the following formula is calculated. In addition, the transmittance at a wavelength of 380 nm is the lowest among the transmittances at wavelengths of 380 to 780 nm both before and after DUV irradiation. Therefore, if the transmittance at a wavelength of 380 nm is higher than a desired value, a transmittance higher than a desired value can be obtained even at a wavelength of 380 to 780 nm.

DELTA alpha = -ln (T1 / T0)

If DUV organic absorption? Is less than 0.095, it can be said that DUV resistance is excellent. The results are shown in Table 1.

<Hydrogen concentration>

[Evaluation of hydrogen concentration by H / Si value]

A glass plate having a thickness of 0.7 mm prepared by the float method was prepared for the glass of the present invention (Example 3, Example 3) and the conventional glass (Prior Art Example, Example 6). For each of the glass plates, secondary ion mass spectrometry was performed on each of the top and bottom surfaces (the side having a large tin content) under the following analytical conditions from the surface to a depth of 10 μm in the thickness direction in the plate thickness direction.

(Analysis condition)

Measurement apparatus: Secondary ion mass spectrometer with dual convergence mass spectrometer (IMS-7f manufactured by CAMECA)

Primary ion species: Cs ⁺

Primary acceleration voltage: 15.0 kV

Primary ion current: 100 nA

Primary angle of incidence (angle from the direction perpendicular to the surface of the sample): about 24.0 °

Raster size: 90 × 90 μm ²

Detection area: 30 占 퐉

Secondary ion polarity: minus

Use of gun for neutralization

Surface coating: material Pt, film thickness about 10 to 20 nm

The average H / Si value at a depth of 10 mu m in the plate thickness direction from the surface of the H / Si profile obtained by secondary ion mass spectrometry was determined.

The results are shown in Fig. As shown in Fig. 1, the hydrogen concentration (concentration calculated from the relationship between H / Si of the sample and H / Si of the standard sample) of the top and bottom surfaces of the glass plate of the present invention is 1 to 2 ㎛, and the hydrogen concentration decreased 47% / ㎛ on the top surface and 25% / ㎛ on the bottom surface in the depth direction. The average hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the top surface of the glass sheet of the present invention was lower than the mean hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the bottom surface.

Further, the hydrogen concentration of the top and bottom surfaces of the glass sheet of the present invention exhibits a substantially parallel decreasing tendency at a depth of 1 to 2 占 퐉 in the thickness direction from the surface, and the maximum value of the ratio of the bottom surface to the top surface of the average hydrogen concentration Was 1.1. On the other hand, the hydrogen concentration of the top and bottom surfaces of the conventional glass plate does not show a parallel decrease tendency at a depth of 1 to 2 占 퐉 in the plate thickness direction from the surface, and the hydrogen concentration does not decrease gradually in the depth direction , And the minimum value of the ratio of the bottom surface to the top surface was 3.3. That is, it was found that the glass plate of the present invention had a smaller hydrogen concentration difference on the surface portion of 1 to 2 탆 in depth between the top surface and the bottom surface, as compared with the conventional product.

<Chamfer processing and measurement>

A glass substrate (original article: Example 3, conventional article: Example 6) in which glass was separated was prepared. The outer periphery of the glass substrate was chamfered for two rounds by using an automatic glass grinder and using a grindstone manufactured by Noritake Co., Ltd. of Kabushiki Kaisha. Here, the infeed amount of the first wheel was 0.1 mm on one side, and the infeed amount on the second wheel was 0.05 mm on the other side. Subsequently, the distance between two points was measured at a magnification of 200x using a microscope made by Keith Co., Ltd., and the number of chippings having a size of 25 占 퐉 or more was counted.

Here, the number of glass chipping of the prior art, which has a large difference in hydrogen concentration between 1 and 2 mu m in depth in the thickness direction from the glass surface of the top and bottom surfaces, The number ratio of chipping of the glass of the present invention having a small concentration difference was 0.7.

Further, as a result of verifying under a plurality of polishing conditions and chemical strengthening treatment conditions, it has been found that a steel sheet having a high compressive stress value (CS value) and a hydrogen concentration difference of 1 to 2 mu m in the thickness direction from the surface of the top and bottom surfaces If the chemical strengthening glass is chemically reinforced chemically strengthened glass, it is also confirmed that the ratio is up to 0.4.

From the above, the present inventors have found that the correlation between the difference in hydrogen concentration between the top and bottom surfaces of the chemical strengthening glass and the amount of defects at the edge portion during chamfering of the chemically strengthened glass with the chemical strengthening glass I found out there was a relationship. That is, the smaller the value of the absolute value of the difference in hydrogen concentration between the top surface and the bottom surface of the chemical strengthening glass, the smaller the amount of the edge defects at the time of chamfering the chemical tempered glass.

<Other characteristics>

For each glass, the glass transition temperature (Tg) and the average thermal expansion coefficient at 30 to 350 占 폚 were measured by a thermomechanical analyzer (TMA). The density of each glass was measured by the Archimedes method. In addition, the Young's modulus of each glass was measured by ultrasonic pulse method. These results are shown together in Table 1.

As can be seen from Table 1, the glass of Examples 1 to 5 is a glass having a small amount of sludge at the time of etching as compared with the glass of Example 6. In addition, the glasses of Examples 1 to 5 have a higher CS compared to the glass of Example 6, when the glass is chemically reinforced under the same chemical strengthening conditions. In addition, the glasses of Examples 1 to 5 are low in DUV organic absorption &amp;alpha; and superior in DUV resistance, as compared to the glass of Example 6.

Although the present invention has been described in detail with reference to specific embodiments thereof, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. The present application is based on Japanese Patent Application (Application No. 2016-223041) filed on November 16, 2016, and Japanese Patent Application (Application No. 2017-190684) filed on September 29, 2017, Is cited by reference. Also, all references cited herein are incorporated by reference in their entirety.

Claims (8)

As a molar percentage indication based on oxide,
SiO ₂ : 60 to 67%
Al ₂ O ₃ : 9 to 13.5%
Na ₂ O: 13.5 to 18.5%
0.1 to 3% of K ₂ O,
MgO: 6 to 10.5% and
TiO ₂ : more than 0% and not more than 5%
Wherein the tin content of the back surface is larger than the tin content of the main surface and the hydrogen concentration at a depth of 1 to 2 占 퐉 in the plate thickness direction from the surface of the main surface gradually decreases in the depth direction Wherein the chemical strengthening glass is a glass reinforcing glass. The chemical strengthening glass according to claim 1, characterized in that the hydrogen concentration at a depth of 1 to 2 占 퐉 in the thickness direction direction from the surface of the back surface gradually decreases in the depth direction. The hydrogen concentration sensor according to claim 1, wherein the hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the main surface is lower than a hydrogen concentration at a depth of 1 to 10 mu m in the thickness direction from the surface of the back surface , Glass for chemical strengthening. The chemical strengthening glass according to any one of claims 1 to 3, wherein the temperature T4 at which the glass has a viscosity of 10 ⁴ dPa 가 is not more than 1255 캜. Any one of claims 1 to A method according to any one of claim 4, wherein the glass for chemical strengthening, including 0.11% of ZrO ₂ to the mole percent of the oxide-based display or less than 4.0%. A chemical strengthening glass in which the chemical strengthening glass according to any one of claims 1 to 5 is chemically reinforced. The chemical strengthening glass according to claim 6, wherein the surface compressive stress (CS) is 900 MPa or more. The chemical strengthening glass according to claim 6 or 7, wherein the compressive stress layer depth (DOL) is 30 占 퐉 or more.

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