CN109970318A

CN109970318A - The manufacturing method of alkali-free glass

Info

Publication number: CN109970318A
Application number: CN201910183470.9A
Authority: CN
Inventors: 德永博文; 小野和孝
Original assignee: AGC Inc
Current assignee: AGC Inc
Priority date: 2013-08-26
Filing date: 2014-08-21
Publication date: 2019-07-05
Also published as: KR20160046809A; WO2015029870A1; CN105492395A; TW201512122A; CN105492395B; JP2016188147A

Abstract

The present invention relates to a kind of manufacturing methods of alkali-free glass, glass raw material is put into fusing kiln, it is heated to 1350~1750 DEG C of temperature and melten glass is made, then the melten glass is configured to by plate by float glass process, wherein, in the heating in the fusing kiln, the electrified regulation of the melten glass of the heating using the burning flame progress of burner and the heating electrode progress configured in the way of in the melten glass to be immersed in the fusing kiln is applied in combination, by the T as clarifying temp of the melten glass_3.3(glass viscosity 10^3.3Temperature, unit when dPas: DEG C) under resistivity be set as Rg (Ω cm), by T_3.3Under the resistivity of refractory material of composition fusing kiln when being set as Rb (Ω cm), the glass raw material and the refractory material are selected in a manner of Rb > Rg.

Description

The manufacturing method of alkali-free glass

The application be the applying date be August in 2014 21, application No. is 201480047420.3, entitled " alkali-frees The divisional application of the Chinese invention patent application of the manufacturing method of glass ".

Technical field

The present invention relates to the alkali-free glasss for being suitable as various base plate for displaying glass or base board for optical mask glass Manufacturing method.

Hereinafter, in the present specification, when mentioning " alkali-free ", referring to alkali metal oxide (Li₂O、Na₂O、K₂O content) is 2000ppm or less.

Background technique

In the past, metal or sull etc. are formed for various base plate for displaying glass, particularly on the surface Base plate for displaying glass, it is desirable that characteristic as shown below.

(1) when containing alkali metal oxide, alkali metal ion spreads into film and deteriorates membrane property, it is therefore desirable to The content of alkali metal oxide is extremely low, specifically, it is desirable that the content of alkali metal oxide is 2000ppm or less.

(2) when being exposed to high temperature in film formation process, in order to by the deformation of glass and with the stable structure of glass The contraction (thermal contraction) of change inhibits in bottom line, it is desirable that strain point is high.

(3) there is sufficient chemical durability to various chemicals used in semiconductor formation.Especially to being used for SiO_x、SiN_xEtching buffered hydrofluoric acid (BHF: the mixed liquor of hydrofluoric acid and ammonium fluoride) and for ITO etching contain salt The reagent of acid, various sour (nitric acid, the sulfuric acid etc.) of etching for metal electrode, the alkali of anticorrosive additive stripping liquid controlling have durability.

(4) internal and surface does not have defect (bubble, brush line, field trash, pit, scar etc.).

Apart from the requirements above, situation as described below is had also appeared in recent years.

(5) lightweight of display is required, it is expected that glass itself is also the small glass of density.

(6) lightweight of display is required, expectation substrate glass is thinned.

(7) other than amorphous silicon (a-Si) type liquid crystal display so far, some heat treatment temperatures have also been made High polysilicon (p-Si) type liquid crystal display (a-Si: about 350 DEG C → p-Si:350~550 DEG C).

(8) in order to accelerate make liquid crystal display heat treatment heating and cooling rate and improve productivity or improve it is resistance to Thermal impact, it is desirable that the small glass of the mean thermal expansion coefficients of glass.

On the other hand, dry etching is developed, and the requirement to resistance to BHF weakens.Glass so far is resistance in order to make BHF is good and uses the B containing 6~10 moles of % more₂O₃Glass.But B₂O₃In the presence of the tendency for reducing strain point. As without B₂O₃Or the example of poor alkali-free glass, there is glass as described below.

The B containing 0~5 mole of % is disclosed in patent document 1₂O₃Glass, but the average thermal expansion at 50~300 DEG C Coefficient is more than 50 × 10^-7/℃。

The strain point for the alkali-free glass recorded in patent document 2 is high, can be formed by float glass process, be suitable for display With purposes such as substrate, base board for optical mask.

The alkali-free glass used in the purposes such as base plate for displaying, base board for optical mask, specifically alkali-free glass The plate glass of composition obtains as follows: being deployed in a manner of obtaining target component to the raw material of each ingredient, continuously by it In investment fusing kiln, it is heated to predetermined temperature and is melted, which is configured to predetermined plate thickness, is cut after annealing It cuts, thus obtains.

In the case where the high glass of strain point, in the fusing of raw material need to be heated to 1350~1750 DEG C as height Temperature.Heating means when as melting sources is generally generated by the burning flame of the burner by the top configured in fusing kiln Heating and be heated to predetermined temperature, but in the case where high temperature as being heated to 1350~1750 DEG C, it is possible to cause to constitute The refractory material of fusing kiln is etched.When the erosion of refractory material occurs, the ingredient of refractory material, which fuses into melten glass, to be caused The quality of the glass of manufacture reduces, and thus leads to the problem of.

As described above, heating means when as melting sources, general by the burner for the top configured in fusing kiln Burning flame and be heated to predetermined temperature, but as supplementary heating means, there is that there are as below methods: to be immersed in fusing kiln Heating electrode is arranged in mode in melten glass, applies DC voltage or alternating voltage to the heating electrode, thus to fusing kiln Interior melten glass carries out electrified regulation (referring to patent document 3,4).Be applied in combination such burning flame using burner into It is effective for the erosion of refractory material of the electrified regulation of capable heating and melten glass for inhibiting to constitute fusing kiln.Structure It is especially easy to happen near the interface of melten glass and upper space at the erosion of the refractory material of fusing kiln.Therefore, group The electrified regulation only heated to melten glass using the atmosphere temperature for not improving upper space is closed for inhibiting fire proofed wood It is effective for the erosion of material.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 5-232458 bulletin

Patent document 2: Japanese Unexamined Patent Publication 10-45422 bulletin

Patent document 3: Japanese Unexamined Patent Publication 2005-132713 bulletin

Patent document 4: Japanese Unexamined Patent Application Publication 2009-523697 bulletin

Summary of the invention

Problem to be solved by the invention

However, although the manufacturing method of the p-Si TFT as high-quality has solid-phase crystallization method, in order to implement the solid phase Crystallisation, it is desirable that further increase strain point.

On the other hand, according to technology for making glass, especially melt, shape in requirement, it is desirable that reduce glass viscosity, Especially glass viscosity reaches 10⁴Temperature T when dPas₄。

But in the case where carrying out electrified regulation to alkali-free glass, it should be noted that following aspect.

Compared with the alkali glass as the soda-lime glass, the content of the alkali metal oxide of alkali-free glass is low, therefore is melting Alkali metal ion present in glass is also few, thus compared with the alkali glass as the soda-lime glass, and electric current is difficult to when electrified regulation Circulation.Therefore, electric current from be arranged in fusing kiln in heating electrode not only into melten glass and also to constitute melt kiln it is resistance to It is also possible to circulate in fiery material.

When having current flowing in the refractory material for constituting fusing kiln, whole electricity of investment can not be used for melten glass Electrified regulation, therefore from the viewpoint of the utilization efficiency of the electricity of investment not preferably.In addition, in the fire resisting for constituting fusing kiln When having current flowing in material, also current flowing is had in the metal component (such as metal framework) around fusing kiln and is existed The risk of electric shock.Furthermore, it is possible to can cause the electrified regulation of refractory material, the temperature of refractory material increases and occurs molten Damage.

It is an object of the invention to solve drawbacks described above and provide one kind be suitable for manufacturing strain point high and low viscosity, Especially glass viscosity is 10⁴Temperature T when dPas₄Low, the especially easy alkali-free glass of float forming method.

The means used to solve the problem

The present invention provides a kind of manufacturing method of alkali-free glass, and glass original is prepared in the way of forming following glass and form Material, investment melt in kiln, are heated to 1350~1750 DEG C of temperature and melten glass is made, the melten glass is then configured to plate Shape, wherein

In the heating in above-mentioned fusing kiln, the heating using the burning flame progress of burner is applied in combination and utilizes to soak The electrified regulation for the melten glass that the heating electrode that mode of the stain in the melten glass in above-mentioned fusing kiln configures carries out,

By the T as clarifying temp of above-mentioned melten glass_3.3(glass viscosity 10^3.3Temperature, unit when dPas: DEG C) under resistivity be set as Rg (Ω cm), by T_3.3Under the resistivity of refractory material of composition fusing kiln be set as Rb (Ω cm) When, above-mentioned glass raw material and above-mentioned refractory material are selected in a manner of Rb > Rg,

To contain based on mole % of oxide:

Also, the alkali metal oxide containing 200~2000ppm,

MgO+CaO+SrO+BaO is 15.5~21,

MgO/ (MgO+CaO+SrO+BaO) is 0.35 or more,

CaO/ (MgO+CaO+SrO+BaO) be 0.50 hereinafter,

SrO/ (MgO+CaO+SrO+BaO) is 0.50 or less.

Invention effect

According to the method for the present invention, can satisfactorily manufacture strain point is the evenly heat at 680~735 DEG C, 50~350 DEG C The coefficient of expansion is 30 × 10^-7~43 × 10^-7/ DEG C, glass viscosity 10²Temperature T when dPas₂For 1710 DEG C or less, glass Viscosity is 10⁴Temperature T when dPas₄For 1310 DEG C of alkali-free glasss below.

Base plate for displaying, light of the alkali-free glass manufactured by means of the present invention particularly suitable for high strain-point purposes Mask substrate etc., in addition, it is the glass for being particularly susceptible for float forming.

In the present invention, by fusing kiln in heating in be applied in combination using burner burning flame carry out heating and Melt kiln in melten glass electrified regulation, be able to suppress 1350~1750 DEG C as be heated at high temperature when composition fusing kiln Refractory material erosion.Thus, it is suppressed that the ingredient of refractory material fuses into melten glass, the product of manufactured alkali-free glass Matter improves.

In the present invention, in the electrified regulation of melten glass, it is suppressed that electric current melts the resistance to of kiln from heating electrode to composition It circulates in fiery material.The utilization efficiency of the electricity put into when electrified regulation as a result, improves.In addition, in the fire resisting for constituting fusing kiln When material has current flowing, also there is current flowing in the metal component (such as metal framework) around fusing kiln and there is electric shock Risk, it is possible to cause the electrified regulation of refractory material, the temperature of refractory material increases and melting loss occurs, but in the present invention Eliminate above-mentioned possibility.

Detailed description of the invention

Fig. 1 is the electricity for indicating melten glass (glass 1) and refractory material (refractory material 1, refractory material 2) in embodiment The curve graph of the measurement result of resistance rate.

Fig. 2 is the electricity for indicating melten glass (glass 2) and refractory material (refractory material 1, refractory material 2) in embodiment The curve graph of the measurement result of resistance rate.

Fig. 3 is the electricity for indicating melten glass (glass 3) and refractory material (refractory material 1, refractory material 2) in embodiment The curve graph of the measurement result of resistance rate.

Specific embodiment

Hereinafter, being illustrated to the manufacturing method of alkali-free glass of the invention.

In the manufacturing method of alkali-free glass of the invention, after being deployed in the way of obtaining following glass and forming Glass raw material,

To contain based on mole % of oxide:

Also, the alkali metal oxide containing 200~2000ppm,

MgO+CaO+SrO+BaO is 15.5~21,

MgO/ (MgO+CaO+SrO+BaO) is 0.35 or more,

CaO/ (MgO+CaO+SrO+BaO) be 0.50 hereinafter,

SrO/ (MgO+CaO+SrO+BaO) is 0.50 or less.

Then the compositing range of each ingredient is illustrated.SiO₂(mole %, below as long as no especially saying lower than 63% It is bright then identical) when, strain point can't improve enough, and thermal expansion coefficient increases, and density increases.Preferably 64% or more, more It preferably 65% or more, is more preferably 66% or more, particularly preferably 66.5% or more.When more than 74%, melting drop It is low, glass viscosity 10²Temperature T when dPas₂It is 10 with glass viscosity⁴Temperature T when dPas₄It increases, devitrification temperature liter It is high.Preferably 70% or less, it is more preferably 69% or less, further preferably 68% or less.

Al₂O₃Inhibit the split-phase of glass, reduce thermal expansion coefficient, will not be showed when improving strain point, but being lower than 11.5% Said effect out, the ratio that the ingredient (such as BaO, SrO) of thermal expansion coefficient is in addition improved in glass composition increases, therefore ties The thermal expansion coefficient of fruit glass increases.Preferably 12% or more, be more preferably 12.5% or more, further preferably 13% with On.When more than 16%, it is possible to which the melting of glass is deteriorated or increases devitrification temperature.Preferably 15% or less, more preferably It is 14% or less, further preferably 13.5% or less.

B₂O₃Keep the melting of glass good, in addition reduce devitrification temperature, improve resistance to BHF, but when being 1.5% or less on State the problem of effect performance is insufficient, and in addition strain point excessively increases or is easy to cause mist degree after the processing based on BHF. Preferably 2% or more, it is more preferably 3% or more.But when more than 5%, strain point is reduced, and Young's modulus reduces.Preferably 4.5% or less, it is more preferably 4% or less.

In alkali earths, MgO, which has, not to be improved expansion and improves as Young's modulus in the state of maintaining low-density Feature also improves melting, but be lower than 5.5% when said effect performance it is insufficient, in addition glass composition in other alkaline earths Class ratio increases thus density increases.Preferably 6% or more, be more preferably 7% or more, more preferably 7.5% or more, more Preferably 8% or more, it is particularly preferably 8.5% or more.When more than 13%, devitrification temperature is increased.Preferably 12% or less, more excellent It is selected as 11% or less, particularly preferably 10% or less.

CaO, which has in alkali earths inferior to MgO, not to be improved expansion and does not reduce feature as strain point excessively, also makes to melt The property changed improves.

When lower than 1.5%, the above-mentioned effect performance as brought by addition CaO is insufficient.Preferably 2% or more, more preferably It is 3% or more, further preferably 3.5% or more, particularly preferably 4% or more.But when more than 12%, it is possible to devitrification temperature Degree raising or the lime stone (CaCO as CaO raw material₃) in the phosphorus as impurity be largely mixed into.Preferably 10% or less, It more preferably 9% or less, is more preferably 8% or less, particularly preferably 7% or less.

SrO improve melting without increasing the devitrification temperature of glass, but be lower than 1.5% when the effect show it is insufficient. Preferably 2% or more, it is more preferably 2.5% or more, further preferably 3% or more.But when more than 9%, it is possible to expand Coefficient increases.Preferably 7% or less, it is more preferably 6% or less, more preferably 5% or less.

BaO is simultaneously nonessential but can contain to improve melting.But when excessive, the expansion and density of glass can be made It is excessively increased, therefore is set as 1% or less.Preferably 0.5% or less, it is more preferably 0.3% or less, is more preferably 0.1% or less, it particularly preferably contains substantially no.It contains substantially no and refers to and do not contained other than inevitable impurity.

About ZrO₂, can be containing extremely in order to reduce glass melting temperature or in order to promote crystal when calcining to be precipitated More 2%.When more than 2%, glass becomes unstable or glass relative dielectric constant ε and becomes larger.Preferably 1.5% or less.More Preferably 1% or less, it is more preferably 0.5% or less, further preferably contains substantially no.

When the total amount of MgO, CaO, SrO, BaO are less than 15.5%, it is possible to glass viscosity 10⁴Temperature T when dPas₄ It increases, extremely shortens the shell structure object of float tank or the service life of heater when float forming.Preferably 16% or more, further Preferably 17% or more.When more than 21%, it is possible to produce difficult point as thermal expansion coefficient can not be reduced.Preferably 20% with Under, more preferably 19% or less, further preferably 18% or less.

Total amount by making MgO, CaO, SrO and BaO meets above-mentioned condition, and meets following conditions, it is possible thereby to not Make raising Young's modulus in the raised situation of devitrification temperature, than elasticity modulus, and then reduces the viscosity of glass, especially reduces T₄。

MgO/ (MgO+CaO+SrO+BaO) is 0.35 or more, preferably 0.37 or more, more preferably 0.4 or more.

CaO/ (MgO+CaO+SrO+BaO) is 0.50 or less, preferably 0.48 or less, more preferably 0.45 or less.

SrO/ (MgO+CaO+SrO+BaO) is 0.50 or less, is preferably 0.40 or less, is more preferably 0.30 or less, is more excellent It is selected as 0.27 or less, further preferably 0.25 or less.

In alkali-free glass of the invention, Al₂O₃Poplar can be improved for 4.3 or more in × (MgO/ (MgO+CaO+SrO+BaO)) Family name's modulus, is therefore preferred.Preferably 4.5 or more, 4.7 or more, further preferably 5.0 or more are more preferably.

In the manufacturing method of alkali-free glass of the invention, in order to carry out electrified regulation to the melten glass in fusing kiln, Make the alkali metal oxide for containing 200~2000ppm (mole) in glass raw material.

Compared with the alkali glass as the soda-lime glass, the content of the alkali metal oxide of alkali-free glass is low, in melten glass Present in alkali metal ion it is also few, therefore electric conductivity is low, is not suitable for electrified regulation originally.

In the present invention, by making the alkali metal oxide in glass raw material containing 200ppm or more, thus in melting glass Alkali metal ion increases in glass, the result is that the resistivity of melten glass reduces.As a result, the electric conductivity of melten glass improves, energy Enough carry out electrified regulation.

Here, alkali metal ion spreads into film and makes membrane property bad when improving the content of alkali metal oxide It is led to the problem of when changing, therefore being used as various base plate for displaying glass, but if making the alkali metal oxidation in glass composition The content of object is 2000ppm or less, preferably 1500ppm or less, more preferably 1300ppm or less, is more preferably 1000ppm is hereinafter, will not then generate such problems.

Glass raw material used in the present invention contains preferably 1500ppm or less, more preferably 1300ppm or less, into one Step is preferably 1000ppm alkali metal oxide below, and further preferably 700ppm or less, further preferably 200~ The alkali metal oxide of 500ppm.

In addition, Na can be enumerated as alkali metal oxide₂O、K₂O、Li₂O, from the effect for the resistivity for reducing melten glass From the perspective of the balance of fruit and cost of material, preferably Na₂O、K₂O, more preferably Na₂O。

It should be noted that the metal or sull when in order not to manufacture panel in glass surface setting generate spy Property deterioration, glass raw material preferably contains substantially no P₂O₅.Further, in order to be easy the recycling of glass, glass raw material is preferably real PbO, As are not contained in matter₂O₃、Sb₂O₃。

In order to improve melting, the clarification, formability of glass, in glass raw material can containing total amount be 1% or less, Preferably 0.5% ZnO, Fe below₂O₃、SO₃、F、Cl、SnO₂.It is preferred that containing substantially no ZnO.

In the present invention, the glass raw material after being deployed in the way of obtaining above-mentioned form continuously is put into fusing kiln In, it is heated to 1350~1750 DEG C and is melted.

Here, the heating carried out using the burning flame of burner and fusing kiln is applied in combination in the heating in fusing kiln The electrified regulation of interior melten glass.

Burner configuration is in the top of fusing kiln, by the burning flame of fossil fuel, specifically liquid such as heavy oil, lam-oil The burning flame of the gaseous fuels such as fluid fuel, LPG etc. is heated.When these fuel combustions, after fuel and oxygen mix can be made It burns or makes fuel and oxygen and air mixing after-combustion.By using these methods, water can be contained in melten glass Point, the β-OH value of manufactured alkali-free glass can be adjusted.

On the other hand, the electrified regulation for melting the melten glass in kiln passes through to be immersed in the melten glass melted in kiln Mode DC voltage is applied to the heating electrode of the bottom or side for being set to the fusing kiln or alternating voltage carries out.But As described later, implement that interelectrode potential difference is preferably made to be held in 100~500V when electrified regulation, but such straight in order to apply Galvanic electricity pressure is needed from can be used as the exchange conversion of commercial use power supply into direct current, therefore preferably applies alternating voltage.

In the electrified regulation of melten glass, cause from the electrolysis in the melten glass being able to suppress in fusing kiln and thus Bubble generate and efficiency when electrified regulation in terms of set out, heating electrode is applied preferably in a manner of meeting following conditions Add alternating voltage,

Local current densities: 0.1~2.0A/cm²

Interelectrode potential difference: 20~500V

The frequency of alternating voltage: 10~90Hz

Local current densities are more preferably 0.2~1.7A/cm², further preferably 0.3~1.0A/cm²。

Interelectrode potential difference is more preferably 30~480V, further preferably 40~450V.

The frequency of alternating voltage is more preferably 30~80Hz, further preferably 50~60Hz.

Material used in electrode is heated other than excellent conductivity, due to the melten glass being immersed in fusing kiln In, therefore also require heat resistance, the excellent corrosion resistance to melten glass.

As the material for meeting above-mentioned requirements, rhodium, iridium, osmium, hafnium, molybdenum, tungsten, platinum and their alloy may be exemplified out.

In the present invention, by the heating amount generated by the burning flame of burner and by the energization of the melten glass in fusing kiln The total of thermogenetic heating amount is added to be set as T₀(J/h) when, preferably met by the heating amount T (J/h) that electrified regulation generates following Formula.

0.10×T₀≤T≤0.40×T₀

T is less than 0.10 × T₀When, it is possible to bring effect, inhibited by being applied in combination the electrified regulation of melten glass The effect for constituting the erosion of the refractory material of fusing kiln becomes inadequate.

T is greater than 0.40 × T₀When, it is possible to the temperature for melting kiln bottom portion increases, and the erosion of refractory material carries out.

It is heated to as 1300~1700 DEG C or 1350~1750 DEG C as melting kiln in the fusing of glass raw material High temperature, therefore using refractory material as constituent material.For constituting the refractory material of fusing kiln, other than heat resistance, Also require the corrosion resistance, mechanical strength, inoxidizability to melten glass.

As the refractory material for constituting fusing kiln, from the excellent corrosion resistance to melten glass, it is preferable to use containing The ZrO of 90 mass % or more₂Zirconium oxide series refractory material.

But alkali composition (the Na for being 0.12 mass % or more containing total amount in above-mentioned zirconium oxide series refractory material₂O、 K₂O) as the ingredient for reducing host glass viscosity, therefore high temperature as being heated to 1300~1700 DEG C or 1350~1750 DEG C When, because the alkali composition there are due to show ionic conductivity.Therefore, when electrified regulation, electric current from be arranged in fusing kiln in Heating electrode not only is also possible to circulate into melten glass but also into the refractory material for constituting fusing kiln.

In the present invention, by the T as clarifying temp of glass_3.3(glass viscosity 10^3.3Temperature, list when dPas Position: DEG C) under resistivity be set as Rg (Ω cm), by T_3.3Under the resistivity of refractory material of composition fusing kiln be set as Rb (Ω When cm), glass raw material is selected in a manner of Rb > Rg and is constituted the refractory material of fusing kiln.

Shown in embodiment as be described hereinafter, the resistivity of melten glass and refractory material is reduced as temperature increases, just opposite For the raised resistivity of temperature reduces, melten glass is greater than refractory material.Therefore, if T_3.3Under resistivity be in Rb The relationship of > Rg, then than above-mentioned higher temperature range (for example, the T of the melting temperature as glass₂(glass viscosity is 10²Temperature, unit when dPas: DEG C)) in, the resistivity of usual refractory material is greater than melten glass.

Therefore, if with T_3.3The mode of lower Rb > Rg is then led to come the refractory material for selecting glass raw material with constituting fusing kiln When electric heating, it can inhibit and circulate from the electric current of heating electrode into the refractory material for constituting fusing kiln.

In the present invention, the ratio between Rb and Rg (Rb/Rg) preferably satisfy Rb/Rg > 1.00, more preferably meet Rb/Rg > 1.05, further preferably meet Rb/Rg > 1.10.

It should be noted that in the case where the alkali-free glass of above-mentioned composition, by changing in the range of 200~2000ppm Become the content of alkali metal oxide, thus, it is possible to adjust Rg.The content of alkali metal oxide is more, then Rg is lower.

In addition, passing through the T for changing manufactured alkali-free glass_3.3, can also adjust Rg.T_3.3Lower, then Rg is lower.

In the case where the suitable composition of aftermentioned refractory material, by changing alkali composition (Na₂O、K₂O content) can be adjusted Save Rb.In addition, by changing the K in alkali composition₂The ratio of O, adjustable Rb.Alkali composition (Na₂O、K₂O content) is lower, then Rb is higher.K in alkali composition₂The more high then Rb of the ratio of O is higher.

The alkali-free glass of above-mentioned composition can be enumerated in terms of quality % and be contained as the refractory material for forming Rb > Rg There is 85~91% ZrO₂, 7.0~11.2% SiO₂, 0.85~3.0% Al₂O₃, 0.05~1.0% P₂O₅, 0.05~ 1.0% B₂O₃And in the total amount be 0.01~0.12% K₂O and Na₂O, and contain Na₂K more than O content₂The hyperoxia of O Change zirconium matter melting casting refractory material.

The Higly oxidized zirconia melting casting refractory material of above-mentioned composition be chemical component 85~91% it is most of in this way by Zirconium oxide (ZrO₂) formed refractory material shown excellent to melten glass using baddeleyite crystal as main composition Corrosion resistance, and the content of alkali composition is few, and mainly contains the K that ionic radius is big and mobility is small₂O as alkali at Point, therefore the resistivity in 1350~1750 DEG C of temperature ranges is big.

Next, being illustrated to the compositing range of each ingredient.

Casting refractory material is melted as Higly oxidized zirconia, the ZrO in refractory material₂Content it is more more then to melten glass Corrosion resistance it is more excellent, therefore be set as 85% or more, be preferably set to 88% or more.But ZrO₂Content be more than When 91%, the amount of host glass is opposite to be reduced, and cannot absorb the volume change associated with the transformation of baddeleyite crystal (i.e. phase transformation), Heat-resisting cyclicity is deteriorated, therefore is set as 91% or less.

SiO₂It is the neccessary composition to be formed for mitigating the host glass of generated stress in refractory material, in order to obtain There is no the melting casting refractory material of the practical dimensions of crackle, needs containing 7.0% or more.But SiO₂The content of ingredient is more When 11.2%, the corrosion resistance of melten glass is reduced, thus be set as 11.2% or less, be preferably set to 10.0% with Under.

Al₂O₃The effect for playing the relationship of the temperature for adjusting host glass and viscosity, also shows reduction matrix in addition to this ZrO in glass₂Content effect.ZrO in host glass₂Content it is few when, can inhibit and sent out in previous refractory material Existing zircon (ZrO₂·SiO₂) precipitation of the crystal in host glass, the accumulation tendency significant decrease of resid vol expansion.

In order to make the ZrO in host glass₂Content be effectively reduced, the Al in refractory material₂O₃Content be set as 0.85% or more, it is preferably set to 1.0% or more.In addition, in order not to occur when being cast or being used refractory material The crystal such as mullite are precipitated in host glass and causes host glass to go bad, crack such problems in refractory material, Al₂O₃Content be set as 3.0% or less.

Therefore, the Al in Higly oxidized zirconia melting casting refractory material₂O₃Content be 0.85~3.0%, preferably 1.0 ~3.0%.For refractory material composition is adjusted to the melting casting fire resisting of Higly oxidized zirconia made of above range is cast Material, the volume increase caused by heat-resisting cyclicity, the accumulation expanded by resid vol can be suppressed and do not ask in practical In the range of topic, and prunes (チップオ Off) phenomenon and improved also significantly.

In addition, also containing B in addition to a small amount of alkali composition₂O₃And P₂O₅Even if thus the content of alkali composition is reduced, matrix glass Viscosity of the glass at 800~1250 DEG C is also adjustable as suitable size, even if being subjected to repeatedly when use through baddeleyite crystal Transformetion range thermal cycle, resid vol expansion also become small, therefore will not show because resid vol expand It accumulates and cracks such tendency.

B₂O₃It is discussed further below such ingredient: itself and P₂O₅It is contained mainly in host glass together, instead of alkali composition With P₂O₅It plays a role that host glass is made to soften together, and the fire resisting within the temperature range of 1350~1750 DEG C will not be made The resistivity of material reduces.

Since the amount that Higly oxidized zirconia melts the host glass in casting refractory material is few, B₂O₃Content be The effect for adjusting the viscosity of host glass is just shown when 0.05% or more.But B₂O₃Content it is excessive when, fine and close melting Casting refractory material becomes unable to cast, therefore B₂O₃Content be set as 0.05~1.0%, be preferably set to 0.10~ 1.0%.

P₂O₅With B₂O₃And alkali composition is contained mostly in host glass together, to the transition temperature model of baddeleyite crystal The viscosity of host glass in enclosing is adjusted (softening), prevents from producing because of the volume change associated with the transformation of baddeleyite crystal Crackle caused by raw stress generates.In addition, P₂O₅And B₂O₃It is when refractory material is used for glass melting kiln, even if depositing It will not make the ingredient of glass coloration melting out the situation into glass.In addition, by P₂O₅When being added in raw material for refractory, The melting of raw material for refractory becomes easy, therefore also has to reduce and carry out casting disappearing for required electric power to refractory material The advantages of consumption.

Here, the amount for the host glass being located in Higly oxidized zirconia melting casting refractory material is few, therefore even if fire proofed wood P in material₂O₅Content it is less, the P in host glass₂O₅Content it is also relatively more, as long as containing in refractory material 0.05% or more P₂O₅It can obtain adjusting the effect of the viscosity of host glass.In addition, P₂O₅Content be more than 1.0% when, The property of host glass changes and shows the production for encouraging the resid vol expansion and the crackle associated with the accumulation of refractory material Raw such tendency, therefore it is suitable for adjusting the P in the refractory material of the viscosity of host glass₂O₅Content be 0.05~ It 1.0%, is preferably 0.1~1.0%.

In addition, be so that the resistivity of the refractory material within the temperature range of 1350~1750 DEG C reaches sufficiently large value, Include K₂O and Na₂Total amount of the content of the alkali composition of O in terms of oxide is set as 0.12% hereinafter, further making alkali composition 50% or more, preferably 70% K small the above are ionic mobility in glass₂O.But K₂O and Na₂The total amount of O is less than When 0.01%, it is difficult to manufacture to flawless melting casting refractory material, therefore K₂O and Na₂The total amount of O is set as 0.01% or more. In addition, making K to make it possible to steadily cast out the Higly oxidized zirconia of flawless melting casting refractory material₂The content of O is more than Na₂The content of O.It is preferred that making Na₂The content of O is 0.008% or more, makes K₂The content of O is 0.02~0.10%.

In addition, the Fe contained in raw material as impurity₂O₃And TiO₂Content as long as in the total amount be 0.55% or less as long as The problem of coloring would not occur in the fusing kiln of the alkali-free glass of above-mentioned glass composition, preferably its total amount is set as being no more than 0.30% amount.In addition, the content of alkaline-earth oxide is preferably total to be lower than without making to contain alkaline-earth oxide in refractory material 0.10%.

As constitute fusing kiln refractory material, preferably containing 88~91% ZrO₂, 7.0~10% SiO₂、1.0 ~3.0% Al₂O₃, 0.10~1.0% P₂O₅And 0.10~1.0% B₂O₃Higly oxidized zirconia as chemical component melts Cast refractory material.

In the present invention, continuously investment melts kiln to the glass composition after being deployed in the way of obtaining above-mentioned form In, it is heated to 1350~1750 DEG C and melten glass is made, the melten glass is then configured to by plate by float glass process, it is possible thereby to Obtain alkali-free glass.More specifically, it is predetermined plate thickness by float forming, is cut after annealing, it is possible thereby to plate The mode of glass obtains alkali-free glass.

It should be noted that the forming process for being configured to plate glass is preferably to draw under float glass process, fusion method, roll-in method, discharge orifice Method, especially consideration productivity, plate glass enlargement when, preferably float glass process.

The strain point of the alkali-free glass (the following are " alkali-free glasss of the invention ") obtained by means of the present invention is 680 ~735 DEG C, it can inhibit thermal contraction when panel manufacture.In addition, the manufacturing method as p-Si TFT, can apply solid-phase crystallization Method.

For alkali-free glass of the invention, further preferred strain point is 685 DEG C or more, be further 690 DEG C with On.Strain point be 690 DEG C or more when, be suitable for high strain-point purposes (for example, plate thickness be 0.7mm or less, preferably 0.5mm with Under, more preferably 0.3mm organic EL below base plate for displaying or illumination substrate；Or plate thickness be 0.3mm or less, The base plate for displaying or illumination substrate of preferably 0.1mm thin plate below).It is 0.7mm or less, is further in plate thickness 0.5mm or less, be further 0.3mm or less, be further export when forming in the forming of 0.1mm plate glass below Speed has the tendency that quickening, therefore the fictive temperature of glass is easy to increase, and the contraction (percent thermal shrinkage) of glass is easy to increase.It is this In the case of, if it is high strain-point glass, it is able to suppress contraction.But strain point is when being more than 735 DEG C, by the glass after forming Glass temperature when glass is transported increases, and can affect to equipment life sometimes.Strain point is preferably 730 DEG C or less, more Preferably 725 DEG C or less.

In addition, the glass transition temperature of alkali-free glass of the invention is preferably 750 DEG C or more, more preferably 760 DEG C with Above, further preferably 770 DEG C or more.

In addition, the mean thermal expansion coefficients of alkali-free glass of the invention at 50~350 DEG C are 30 × 10^-7~43 × 10^-7/ DEG C, thermal shock resistance increases, and can be improved productivity when panel manufacture.For alkali-free glass of the invention, 50~ Mean thermal expansion coefficients at 350 DEG C are preferably 35 × 10^-7~43 × 10^-7/℃。

Further, the specific gravity of alkali-free glass of the invention is preferably 2.65 or less, is more preferably 2.64 or less, is further Preferably 2.62 or less.

In addition, the T of alkali-free glass of the invention₂It is 1710 DEG C or less, preferably less than 1710 DEG C, more preferably 1700 DEG C Below, it is more preferably 1690 DEG C to be easier hereinafter, therefore melting.

In addition, the T of alkali-free glass of the invention_3.3For 1430 DEG C or less, preferably less than 1420 DEG C, more preferably 1410 DEG C or less, further preferably 1400 DEG C hereinafter, therefore clarification be easier.

In addition, the viscosity of alkali-free glass of the invention is 10⁴Temperature T when dPas₄For 1310 DEG C or less, preferably 1305 DEG C or less, more preferably 1300 DEG C or less, further preferably lower than 1300 DEG C, 1295 DEG C or less, 1290 DEG C hereinafter, fit Together in float forming.

In addition, from the forming become easy using float glass process, the devitrification temperature of alkali-free glass of the invention is preferably 1315 DEG C or less.Preferably 1300 DEG C or less, lower than 1300 DEG C, 1290 DEG C or less, be more preferably 1280 DEG C or less.In addition, reaching To float forming, melt forming benchmark when temperature T₄(glass viscosity 10⁴Temperature, unit when dPas: DEG C) with Difference (the T of devitrification temperature₄Devitrification temperature) it is preferably -20 DEG C or more, -10 DEG C or more, be further 0 DEG C or more, is more preferably 10 DEG C or more, further preferably 20 DEG C or more, be particularly preferably 30 DEG C or more.

Devitrification temperature in this specification obtains as follows: being put into smashed glass particle in platinum vessel, is controlling It is heat-treated to carry out 17 hours in the electric furnace of steady temperature, by the optical microphotograph sem observation after heat treatment, obtains in glass The average value on surface and the internal maximum temperature precipitated crystal and the minimum temperature not precipitated crystal.

In addition, the Young's modulus of alkali-free glass of the invention be preferably 78GPa or more, more preferably 79GPa or more, It 80GPa or more, is further 81GPa or more, further preferably 82GPa or more.

In addition, the photoelastic constant of alkali-free glass of the invention is preferably 31nm/MPa/cm or less.

Since glass substrate is because of the stress that generates when panel of LCD manufacturing process or LCD device use And the phenomenon that there is birefringence, observe display graying, liquid crystal display the contrast reduction of black sometimes.By making light Elastic constant is 31nm/MPa/cm hereinafter, the phenomenon can be suppressed to smaller.Preferably 30nm/MPa/cm or less, more preferably For 29nm/MPa/cm or less, further preferably 28.5nm/MPa/cm or less, particularly preferably 28nm/MPa/cm or less.

Furthermore, it is contemplated that ensuring the easiness of other physical property, the photoelastic constant of alkali-free glass of the invention is preferably photoelastic Property constant be 23nm/MPa/cm or more, further preferably 25nm/MPa/cm or more.

It should be noted that photoelastic constant can be measured by disk compression method in the case where measuring wavelength 546nm.

β-OH the value of alkali-free glass can be suitably selected according to the requirement characteristic of alkali-free glass.In order to improve alkali-free glass Strain point, preferably β-OH value it is lower.For example, preferably β-OH value is set as in the case where making 725 DEG C of strain point or more 0.3mm^-1Below, more preferably it is set as 0.25mm^-1Below, further preferably it is set as 0.2mm^-1Below.

Various conditions when β-OH value can be melted by raw material, melt in kiln the amount of moisture in such as glass raw material Residence time of melten glass in water vapor concentration, fusing kiln etc. is adjusted.As the amount of moisture adjusted in glass raw material Method, there are use hydroxide to replace oxide as the method for glass raw material (for example, using magnesium hydroxide (Mg (OH)₂) magnesia (MgO) is replaced to be used as magnesium source).In addition, utilizing combustion as the method for adjusting the water vapor concentration in fusing kiln When burner is burnt, there are fossil fuel and oxygen mix and the method burnt and oxygen and air are mixed combining combustion Method.

Embodiment

To melten glass and refractory material (oxidation zirconium Electrocast refractory) within the temperature range of 1300~1700 DEG C Resistivity be measured.

For melten glass (glass 1, glass 2, glass 3), to the original of each ingredient in the way of obtaining as shown below form Material deployed, using platinum crucible 1600 DEG C at a temperature of melt.When fusing, it is stirred using platinum agitator and carries out glass Glass homogenizes.By following in the state that the obtained melten glass to be held in 1300~1700 DEG C of temperature range The method measurement resistivity recorded in document.

" conductimetric method of ionic melt, crop field can give birth to, Gong Yongguang, forever strong time gloomy, Liu Lai exert oneself, Japanese metallography Can will volume 45 the 10th (1981) 1036~1043 " (" イオ Application melt body electric conductivity measuring method, crop field can give birth to, Gong Yong Light, forever strong time gloomy, willow ヶ shallow is exerted oneself, Japanese metallography understands will volume 45 the 10th (1981) 1036~1043 ")

[glass 1]

It forms (based on mole % of oxide)

[glass 2]

It forms (based on mole % of oxide)

[glass 3]

It forms (based on mole % of oxide)

In addition to these, by Na₂O content is changed to be calculated as 200ppm and 1000ppm two ways based on oxide And it adds.

In addition, being following oxidation zirconium Electrocast refractory (refractory material 1, fire resisting for chemical composition, mineral composition Material 2), the measuring principle of the volume resistivity (Section 14) of " JIS C2141 electrical isolation ceramic material test method " is expanded Under exhibition to high temperature (sample is set in electric furnace and is heated), state within the temperature range of being held in 700~1600 DEG C Lower measurement resistivity.

[refractory material 1]

Chemical composition (quality %)

Mineral composition (quality %)

Baddeleyite (バテライト) 88

Glass phase 12

[refractory material 2]

Chemical composition (quality %)

Mineral composition (quality %)

Baddeleyite 88

Glass phase 12

The measurement result of the resistivity of glass 1 is shown in Fig. 1, the measurement result of the resistivity of glass 2 is shown in Fig. 2, is incited somebody to action The measurement result of the resistivity of glass 3 is shown in Figure 3.In Fig. 1, Fig. 2, Fig. 3, Na₂The result of O=200ppm, 1000ppm is Measured value is in addition to this calculated value.The T of glass 1_3.3For 1393 DEG C, the T of glass 2_3.3For 1378 DEG C, the T of glass 3_3.3For 1396℃.According to Fig. 1, Fig. 2, Fig. 3 it will be apparent that, glass 1, glass 2, glass 3 Na₂O content is the feelings of 200ppm or more Under condition, the T of refractory material 1_3.3Under resistivity Rb relative to T_3.3Under the resistivity Rg of melten glass meet the pass of Rb > Rg System.In addition, in T_3.3Within the scope of above temperature and the resistivity of refractory material 1 is higher than melten glass.Think if utilized Such refractory material 1 constitute fusing kiln then electrified regulation when inhibit electric current from heating electrode to the fire proofed wood for constituting fusing kiln It circulates in material.

Glass 1, glass 2, glass 3 Na₂In the case that O content is lower than 200ppm, T_3.3Under resistivity Rb, Rg formed The relationship of Rb < Rg.

On the other hand, glass 1, glass 2, glass 3 Na₂O content is any situation of 200ppm, 1000ppm Under, the T of refractory material 2_3.3Under resistivity Rb relative to T_3.3Under the resistivity Rg of melten glass be all satisfied the pass of Rb < Rg System.In addition, in T_3.3Within the scope of above temperature and the resistivity of refractory material 2 is lower than melten glass.Think using in this way Refractory material 2 constitute fusing kiln in the case where electrified regulation when electric current from heating electrode to constitute fusing kiln refractory material in Circulation.

In following, example 1~23, example 27~28 are embodiment, and example 24~26 is comparative example.It will be to obtain the side that target forms Formula the raw material of each ingredient is deployed after the fusing kiln that is constituted using above-mentioned refractory material 1 of substance investment in, 1500~ It is melted at a temperature of 1600 DEG C.In the heating of fusing kiln, the heating and benefit carried out using the burning flame of burner is applied in combination To be immersed in the electrified regulation for the melten glass that the heating electrode that the mode in the melten glass in kiln that melts configures carries out. It should be noted that being 0.5A/cm in local current densities when electrified regulation², interelectrode potential difference be 300V, frequency is Alternating voltage is applied to heating electrode under the conditions of 50Hz.

It should be noted that in the heating amount that will be generated by the burning flame of burner and by the melten glass in fusing kiln The total of heating amount that electrified regulation generates is set as T₀(J/h) when, T=is met by the heating amount T (J/h) that electrified regulation generates 0.30×T₀Relationship.

Shown in table 1~4: glass form at (unit: mole %) and 50~350 DEG C thermal expansion coefficient (unit: × 10^-7/ DEG C), strain point (unit: DEG C), glass transition temperature (unit: DEG C), specific gravity, Young's modulus (GPa) (utilize ultrasonic wave Method is measured), (in a manner of high temperature viscometrics value) as melting benchmark temperature T₂(glass viscosity 10²When dPas Temperature, unit: DEG C), as the temperature T of clarification benchmark_3.3(glass viscosity 10^3.3Temperature, unit when dPas: DEG C), As the temperature T for drawing the formabilities benchmark such as method under float glass process, fusion method, roll-in method, discharge orifice₄(glass viscosity 10⁴When dPas Temperature, unit: DEG C) and devitrification temperature (unit: DEG C), photoelastic constant (unit: nm/MPa/cm) (using be configured to plate and Sample after annealing is measured by disk compression method in the case where measuring wavelength 546nm) and relative dielectric constant (use at Sample after shape is plate and anneals is measured by the method recorded in JIS C-2141).The evaluation of percent thermal shrinkage passes through Following step carries out.By sample+100 DEG C of glass transition temperature at a temperature of keep after ten minutes, it is cold with 40 DEG C per minute But to room temperature.Total length of sample is measured at this.Then, 600 DEG C are heated to 100 DEG C per hour, are protected at 600 DEG C It holds 80 minutes, is cooled to room temperature with 100 DEG C per hour, the total length of sample is measured again.Before being heat-treated at 600 DEG C The shrinkage of sample afterwards with 600 DEG C at be heat-treated before the ratio between sample total length be used as percent thermal shrinkage.

It should be noted that value shown in bracket is calculated value in table 1~4.

[table 1]

[table 2]

[table 3]

[table 4]

According to showing aobvious it is found that the glass of embodiment is thermal expansion coefficient down to 30 × 10^-7~43 × 10^-7/ DEG C, answer Also up to 680~735 DEG C of height, can be substantially resistant to by the heat treatment under high temperature.

Temperature T as melting benchmark₂Also it is easy hereinafter, melting for relatively low at 1710 DEG C.In addition, T_3.3It is 1430 DEG C Hereinafter, clarification is easier.In addition, the temperature T as formability benchmark₄For 1310 DEG C hereinafter, especially with float glass process at It describes easily.In addition, devitrification temperature is 1320 DEG C or less, it is believed that be especially not in generate the puzzlement such as devitrification in float forming.

Photoelastic constant is 31nm/MPa/cm hereinafter, in the case where being used as the glass substrate of liquid crystal display, can be pressed down The reduction of contrast processed.

In addition, relative dielectric constant is 5.6 or more, and in the case where being used as the glass substrate of inline type touch panel, touching The sensing sensitivity for touching sensor improves.

The present invention is illustrated in detail and referring to specific embodiment above, but those skilled in the art are clear Know to Chu that various amendments or change can be carried out in the case where not departing from the scope of the present invention and spirit.

The application is based on Japanese patent application 2013-174621, side of the content to refer to filed on August 26th, 2013 Formula is incorporated herein.

Practicability in industry

The strain point of alkali-free glass of the invention is high, is suitable for the purposes such as base plate for displaying, base board for optical mask.Separately Outside, the purposes such as substrate used for solar batteries, glass substrate for disc are also suitable for.

Claims

1. a kind of manufacturing method of alkali-free glass prepares glass raw material, investment fusing kiln in the way of forming following glass and form In, it is heated to 1350~1750 DEG C of temperature and melten glass is made, the melten glass is then configured to plate, wherein

In the heating in the fusing kiln, the heating using the burning flame progress of burner is applied in combination and utilizes to be immersed in The electrified regulation for the melten glass that the heating electrode that the mode in melten glass in the fusing kiln configures carries out,

By the T as clarifying temp of the melten glass_3.3Under resistivity be set as Rg, by T_3.3Under composition fusing kiln it is resistance to When the resistivity of fiery material is set as Rb, the glass raw material and the refractory material are selected in a manner of Rb > Rg, wherein T_3.3It is Glass viscosity is 10^3.3Temperature, unit when dPas: DEG C, the unit of Rb, Rg are Ω cm,

The glass composition is to contain based on mole % of oxide:

Also, the alkali metal oxide containing 200~2000ppm,

MgO+CaO+SrO+BaO is 15.5~21,

MgO/ (MgO+CaO+SrO+BaO) is 0.35 or more,

CaO/ (MgO+CaO+SrO+BaO) be 0.50 hereinafter,

SrO/ (MgO+CaO+SrO+BaO) is 0.50 or less.

2. the manufacturing method of alkali-free glass as described in claim 1, wherein glass composition is as follows,

To contain based on mole % of oxide:

Also, the alkali metal oxide containing 200~2000ppm,

MgO+CaO+SrO+BaO is 15.5~21,

MgO/ (MgO+CaO+SrO+BaO) is that 0.35 or more, CaO/ (MgO+CaO+SrO+BaO) is 0.50 hereinafter, SrO/ (MgO+ It CaO+SrO+BaO) is 0.30 or less.

3. the manufacturing method of alkali-free glass as claimed in claim 1 or 2, wherein full with the ratio between the Rb and the Rg Rb/Rg The mode of sufficient following formula selects the glass raw material and the refractory material,

Rb/Rg > 1.00.

4. the manufacturing method of alkali-free glass according to any one of claims 1 to 3, wherein the burning of burner will be utilized The heating amount and be set as T using the total of heating amount of the electrified regulation generation of the melten glass in fusing kiln that flame generates₀When, benefit Meet following formula with the heating amount T that electrified regulation generates,

0.10×T₀≤T≤0.40×T₀, wherein T, T₀Unit be J/h.

5. the manufacturing method of alkali-free glass as described in any one of claims 1 to 4, wherein constitute the resistance to of the fusing kiln Fiery material is Higly oxidized zirconia melting casting refractory material as described below: as the chemical component of the refractory material, with matter % meter is measured containing 85~91% ZrO₂, 7.0~11.2% SiO₂, 0.85~3.0% Al₂O₃, 0.05~1.0% P₂O₅, 0.05~1.0% B₂O₃And in the total amount be 0.01~0.12% K₂O and Na₂O, and contain Na₂O content with On K₂O。

6. such as the manufacturing method of alkali-free glass according to any one of claims 1 to 5, wherein with local current densities for 0.1 ~2.0A/cm², mode that interelectrode potential difference is 20~500V, applying frequency to the heating electrode is 10~90Hz's Alternating voltage.