JP3897194B2 - Alkali-free glass and method for producing the same - Google Patents
Alkali-free glass and method for producing the same Download PDFInfo
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- JP3897194B2 JP3897194B2 JP21579397A JP21579397A JP3897194B2 JP 3897194 B2 JP3897194 B2 JP 3897194B2 JP 21579397 A JP21579397 A JP 21579397A JP 21579397 A JP21579397 A JP 21579397A JP 3897194 B2 JP3897194 B2 JP 3897194B2
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- glass
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- free glass
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Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/11—Glass compositions containing silica with 40% to 90% silica, by weight containing halogen or nitrogen
Description
【0001】
【産業上の利用分野】
本発明は、無アルカリガラス、特にディスプレイ等の透明ガラス基板として使用される無アルカリガラスとその製造方法に関するものである。
【0002】
【従来の技術】
従来、液晶ディスプレイ等の透明ガラス基板として、無アルカリガラスが使用されている。ディスプレイ用途に用いられる無アルカリガラスには、耐熱性、耐薬品性等の特性の他に、表示欠陥となる泡がないことが要求される。
【0003】
このような無アルカリガラスとして、従来より種々のガラスが提案されており、本出願人も特開昭63−74935号においてSiO2 −Al2 O3 −B2 O3 −CaO−BaO系の無アルカリガラスを提案している。
【0004】
【発明が解決しようとする課題】
泡のないガラスを得るためには、ガラス化反応が始まる比較的低い温度域と、ガラス融液の脱泡、均質化が起こる比較的高い温度域の両方で清澄ガスを発生する清澄剤を選択することが重要である。これは、原料がガラス化反応を起こすときに発生するガスを追い出すとともに、脱泡、均質化過程でガラス融液中に残った微小な泡を大きくすることにより浮上させて除去するためである。
【0005】
ところで液晶ディスプレイ用ガラス基板に使用されるような無アルカリガラスは、ガラス融液の粘度が高く、アルカリ成分を含有するガラスに比べてより高温で溶融が行われる。この種の無アルカリガラスでは、通常1200〜1300℃でガラス化反応が起こり、1400℃以上の高温で脱泡、均質化が行われる。このため清澄剤には幅広い温度域(1200〜1600℃程度)で清澄ガスを発生させることができるものが必要とされ、現在ではAs2 O3 が広く使用されている。
【0006】
しかしながらAs2 O3 は毒性が非常に強く、ガラスの製造工程や廃ガラスの処理時等に環境を汚染する可能性があり、その使用が制限されつつある。
【0007】
本発明の目的は、清澄剤としてAs2 O3 を使用せず、しかも表示欠陥となる泡が存在しない無アルカリガラスとその製造方法を提供することである。
【0008】
【課題を解決するための手段】
本発明者等は、種々の実験を行った結果、清澄剤としてAs2 O3 の代わりにSnO2 とSb2 O3 と塩化物を併用することによって上記目的が達成できることを見いだし、本発明として提案するものである。
【0009】
即ち、本発明の無アルカリガラスは、重量百分率でSiO2 40〜70%、Al2O3 6〜25%、B2O3 5〜20%、MgO 0〜10%、CaO 0〜15%、BaO 0〜30%、SrO 0〜10%、ZnO 0〜10%、SnO2 0.05〜2%、Sb2O3 0.05〜1.2%、Cl2 0.005〜1%の組成を有し、本質的にアルカリ金属酸化物を含有しないことを特徴とする。
【0010】
また本発明の無アルカリガラスの製造方法は、重量百分率でSiO2 40〜70%、Al2O3 6〜25%、B2O3 5〜20%、MgO 0〜10%、CaO 0〜15%、BaO 0〜30%、SrO 0〜10%、ZnO 0〜10%の組成を有し、本質的にアルカリ金属酸化物を含有しないガラスとなるように調合したガラス原料調合物を溶融した後、成形する無アルカリガラスの製造方法において、ガラス原料調合物に清澄剤としてSnO2を0.05〜2重量%、Sb2O3を0.05〜1.2重量%及び塩化物をCl2換算で0.01〜2%添加することを特徴とする。
【0011】
【作用】
本発明において使用するSnO2 とSb2 O3 は、SnイオンとSbイオンの価数変化による化学反応により多量の清澄ガス(酸素ガス)を発生する。即ち、Sb2 O3(3価)は、数100℃の低温域で一旦Sb2 O5(5価)に変化した後、1200〜1300℃付近で再びSb2 O3 (3価)に戻る際に多量の清澄ガスを放出し、SnO2 (4価)は1400℃以上でSnOに(2価)変化する際に多量の清澄ガスを放出する。また塩化物は、1200℃以上の温度域で分解、揮発して清澄ガス(塩素ガス等)を発生するが、特に1400℃以上の高温域で分解、揮発が激しくなり、多量の清澄ガスを発生する。
【0012】
従って清澄剤としてSnO2 とSb2 O3 と塩化物を併用することにより、比較的低温で起こるガラス化反応時から高温の均質化溶融時にかけての広い温度域で高い清澄効果が得られるため、表示欠陥となる泡が存在しない無アルカリガラスを得ることができる。
【0013】
次に、本発明の無アルカリガラスの製造方法を述べる。
【0014】
まず、所望の組成を有するガラスとなるようにガラス原料調合物を用意する。ガラスの組成範囲及びその限定理由を以下に述べる。
【0015】
SiO2 はガラスのネットワークとなる成分であり、その含有量は40〜70%、好ましくは45〜65%である。SiO2 が40%より少ないと耐薬品性が悪化するとともに、歪点が低くなって耐熱性が悪くなり、70%より多いと高温粘度が大きくなって溶融性が悪くなるとともに、クリストバライトの失透物が析出し易くなる。
【0016】
Al2 O3 はガラスの耐熱性、耐失透性を高める成分であり、その含有量は6〜25%、好ましくは10〜20%である。Al2 O3 が6%より少ないと失透温度が著しく上昇してガラス中に失透が生じ易くなり、25%より多いと耐酸性、特に耐バッファードフッ酸性が低下してガラス基板表面に白濁が生じ易くなる。
【0017】
B2 O3 は融剤として働き、粘性を下げて溶融を容易にする成分であり、その含有量は5〜20%、好ましくは6〜15%である。B2 O3 が5%より少ないと融剤としての効果が不十分となり、20%より多いと耐塩酸性が低下するとともに、歪点が低下して耐熱性が悪化する。
【0018】
MgOは歪点を下げずに高温粘度を下げてガラスの溶融を容易にする成分であり、その含有量は0〜10%、好ましくは0〜7%である。MgOが10%より多いとガラスの耐バッファードフッ酸性が著しく低下する。CaOもMgOと同様の働きをし、その含有量は0〜15%、好ましくは0〜10%である。CaOが15%より多いとガラスの耐バッファードフッ酸性が著しく低下する。BaOはガラスの耐薬品性を向上させるとともに失透性を改善する成分であり、その含有量は0〜30%、好ましくは0〜20%である。BaOが30%より多いと歪点が低下して耐熱性が悪くなる。SrOはBaOと同様の効果があり、その含有量は0〜10%、好ましくは0〜7%である。SrOが10%より多いと失透性が増すため好ましくない。ZnOは耐バッファードフッ酸性を改善するとともに失透性を改善する成分であり、その含有量は0〜10%、好ましくは0〜7%である。ZnOが10%より多いと逆にガラスが失透し易くなり、また歪点が低下して耐熱性が得られなくなる。なおMgO、CaO、BaO、SrO及びZnOの合量が5%より少ないと高温粘性が高くなって溶融性が悪化するとともに、ガラスが失透し易くなり、30%より多いと耐熱性及び耐酸性が悪くなり好ましくない。
【0019】
また上記成分の他に、ZrO2、TiO 2 等を合量で5%まで添加することができる。
【0020】
次にガラス原料調合物にSnO2とSb2O3と塩化物を添加する。塩化物としては、BaCl2、CaCl2等が使用できる。なおSnO2及びSb2O3の添加量は、ガラス原料調合物100重量%に対して0.05〜2重量%及び0.05〜1.2重量%であり、塩化物はCl2換算で0.01〜2重量%である。Sb2O3が0.05%より少ないとガラス化反応時に発生したガスを追い出し難くなり、SnO2が0.05%より少ない場合、及び塩化物が0.01%より少ない場合は均質化溶融時にガラス融液中に残った泡を除去し難くなる。一方、SnO2が2%、Sb2O3が1.2%より多いとガラスが失透し易くなり、また塩化物が2%より多いと揮発量が多くなりすぎてガラスが変質し易くなる。
【0021】
続いて調合したガラス原料を溶融する。ガラス原料を加熱していくとまずガラス化反応が起こるが、このときSb2 O3 の価数変化による化学反応によって酸素ガスが発生し、ガラス化反応時に発生したガスが融液中から追い出される。さらにより高温の均質化溶融時には、SnO2 の価数変化による化学反応で酸素ガスが発生するとともに、塩化物の分解、揮発によって塩素ガス等が発生してガラス融液中に残存する微小な泡が除去される。
【0022】
その後、溶融ガラスを所望の形状に成形する。ディスプレイ用途に使用する場合、フュージョン法、ダウンドロー法、フロート法、ロールアウト法等の方法を用いて薄板状に成形する。
【0023】
このようにして、重量百分率でSiO2 40〜70%、Al2O3 6〜25%、B2O3 5〜20%、MgO 0〜10%、CaO 0〜15%、BaO 0〜30%、SrO 0〜10%、ZnO 0〜10%、SnO2 0.05〜2%、Sb2O3 0.05〜1.2%、Cl2 0.005〜1%の組成を有し、本質的にアルカリ金属酸化物を含有しない本発明の無アルカリガラスを得ることができる。
【0024】
【実施例】
以下、実施例に基づいて本発明を説明する。
【0025】
(実施例1)
表1は、SnO2 、Sb2 O3 及び塩化物の効果を示したものであり、試料aはAs2 O3 を清澄剤として添加した従来の無アルカリガラス、試料bは試料aからAs2 O3 を除いて作製した無アルカリガラス、試料cはSnO2 のみを添加した無アルカリガラス、試料dはSb2 O3 のみを添加した無アルカリガラス、試料eは塩化物(BaCl2 )のみを添加した無アルカリガラス、試料fはSnO2 、Sb2 O3 及び塩化物を併用した本発明の無アルカリガラスを示している。
【0026】
【表1】
【0027】
各試料は次のようにして調製した。
【0028】
表の組成を有するガラス原料調合物となるようにガラス原料を調合し、電気炉にて溶融した。このとき、ガラス化反応時の清澄性を評価するために1500℃で1時間溶融したものと、均質化溶融時の清澄性を評価するために1550℃で1時間溶融したものの2種類を用意した。次いで、溶融ガラスをカーボン台上に流しだし、徐冷した後、ガラス中に残存している泡の個数を計数し、ガラス100g中の泡が1000個を越えるものを×、101〜1000個のものを△、11〜100個のものを○、10個以下のものを◎で評価した。結果を表1に示す。なお表中のガラス原料調合物組成は、各成分を酸化物換算した値であり、また塩化物はCl2 換算した値で示す。
【0029】
表1から明らかなように、清澄剤を全く添加しない試料bのガラスは清澄性が著しく悪かった。SnO2 のみを添加した試料cのガラスは、均質化溶融時に多量の清澄ガスを発生したものの、ガラス化反応時の清澄性が不十分であったために、結果としてAs2 O3 を添加した試料aのガラスより清澄性が劣っていた。同様に塩化物のみを添加した試料eのガラスも、均質化溶融時に多量の清澄ガスを発生したものの、ガラス化反応時に十分なガスが発生しなかったため、結果として清澄性が悪かった。Sb2 O3 のみを添加した試料dのガラスは、ガラス化反応時に多量の清澄ガスが発生したものの、均質化溶融時に十分な清澄ガスが発生せず、結果として清澄性が悪かった。一方、SnO2 、Sb2 O3 及び塩化物を添加した試料fのガラスは、As2 O3 を添加した試料aのガラスと同様、清澄性が良好であった。
【0030】
(実施例2)
表2及び表3は、本発明の方法により得られる無アルカリガラスの実施例(試料No.1〜7)を示している。
【0031】
【表2】
【0032】
【表3】
【0033】
各試料は次のようにして調製した。
【0034】
表の組成を有するガラスとなるようにガラス原料を調合し、実施例1と同様にして清澄性を評価した。またこれらのガラス原料調合物を電気炉にて1550〜〜1600℃で16〜24時間溶融し、成型して試料を得た。塩化物としてはBaCl2 を使用した。このようにして得られた各試料について、耐熱性及び耐薬品性を評価した。結果を各表に示す。なお表中のガラス組成は、各成分を酸化物換算した値であり、また塩化物はガラス中に残存する量をCl2 換算した値で示してある。
【0035】
表から明らかなように、各試料とも清澄性に優れ、しかも耐熱性、耐薬品性の特性についても良好であった。
【0036】
なお耐熱性は、歪点をASTM C336−71の方法に基づいて測定した。耐薬品性は、耐塩酸性について各試料を80℃に保持された10重量%塩酸水溶液に24時間浸漬した後、ガラス基板の表面状態を観察することによって評価し、ガラス基板表面が変色したものを×、全く変色がないものを○で示した。また耐バッファードフッ酸性は、各試料を20℃に保持された38.7重量%フッ化アンモニウムと1.6重量%フッ酸からなるバッファードフッ酸に30分間浸漬した後、ガラス基板の表面状態を観察することによって評価し、ガラス基板表面が白濁したものを×、全く変化しなかったものを○で示した。
【0037】
【発明の効果】
以上説明したように、本発明の方法によれば、清澄剤としてSnO2 とSb2 O3 と塩化物を併用するために清澄性に優れ、表示欠陥となる泡が存在しない無アルカリガラスを製造することが可能である。
【0038】
また、本発明の無アルカリガラスは、表示欠陥となる泡がなく、かつ優れた耐熱性、耐薬品性を有しており、特にディスプレイ用透明ガラス基板として好適である。[0001]
[Industrial application fields]
The present invention relates to an alkali-free glass, in particular, an alkali-free glass used as a transparent glass substrate for a display or the like, and a method for producing the same.
[0002]
[Prior art]
Conventionally, alkali-free glass has been used as a transparent glass substrate for liquid crystal displays and the like. In addition to characteristics such as heat resistance and chemical resistance, alkali-free glass used for display applications is required to have no bubbles that cause display defects.
[0003]
As such an alkali-free glass, various glasses have been proposed, and the applicant of the present application also disclosed in JP-A 63-74935 that there is no SiO 2 —Al 2 O 3 —B 2 O 3 —CaO—BaO type. Alkaline glass is proposed.
[0004]
[Problems to be solved by the invention]
In order to obtain a glass without bubbles, select a clarifier that generates a clarified gas both in the relatively low temperature range where the vitrification reaction begins and in the relatively high temperature range where defoaming and homogenization of the glass melt occur. It is important to. This is because the gas generated when the raw material undergoes a vitrification reaction is expelled, and the fine bubbles remaining in the glass melt are increased and removed by defoaming and homogenization, thereby removing them.
[0005]
By the way, the alkali-free glass used for the glass substrate for liquid crystal displays has a high viscosity of the glass melt, and is melted at a higher temperature than glass containing an alkali component. In this kind of alkali-free glass, a vitrification reaction usually occurs at 1200 to 1300 ° C., and defoaming and homogenization are performed at a high temperature of 1400 ° C. or higher. For this reason, a refining agent that can generate a refining gas in a wide temperature range (about 1200 to 1600 ° C.) is required, and currently As 2 O 3 is widely used.
[0006]
However, As 2 O 3 is very toxic and may contaminate the environment during the glass production process or waste glass treatment, and its use is being restricted.
[0007]
An object of the present invention is to provide an alkali-free glass that does not use As 2 O 3 as a fining agent and does not have bubbles that cause display defects, and a method for producing the same.
[0008]
[Means for Solving the Problems]
As a result of various experiments, the present inventors have found that the above object can be achieved by using SnO 2 , Sb 2 O 3 and chloride in combination instead of As 2 O 3 as a clarifying agent. It is what we propose.
[0009]
That is, the alkali-free glass of the present invention is SiO 2 40-70%, Al 2 O 3 6-25%, B 2 O 3 5-20%, MgO 0-10%, CaO 0-15% by weight percentage, BaO 0~30%, SrO 0~10%, 0~10% ZnO, SnO 2 0.05~2%, Sb 2 O 3 0.05~ 1.2%, Cl 2 0.005~1% composition And is essentially free of alkali metal oxides.
[0010]
The process for producing an alkali-free glass of the present invention, SiO 2 40 to 70% by weight percentage, Al 2 O 3 6~25%, B 2 O 3 5~20%, 0~10% MgO, CaO 0~15 %, BaO 0 to 30%, SrO 0 to 10%, ZnO 0 to 10%, after melting a glass raw material composition prepared so as to be essentially glass containing no alkali metal oxide In the method for producing alkali-free glass to be molded, 0.05 to 2 % by weight of SnO 2 as a fining agent, 0.05 to 1.2 % by weight of Sb 2 O 3 and chloride as Cl 2 It is characterized by adding 0.01 to 2% in terms of conversion.
[0011]
[Action]
SnO 2 and Sb 2 O 3 used in the present invention generate a large amount of clarified gas (oxygen gas) by a chemical reaction due to a valence change of Sn ions and Sb ions. That is, Sb 2 O 3 (trivalent) temporarily changes to Sb 2 O 5 (pentavalent) at a low temperature range of several hundreds of degrees centigrade, and then returns to Sb 2 O 3 (trivalent) again at around 1200 to 1300 ° C. At that time, a large amount of clarified gas is released. When SnO 2 (tetravalent) changes to SnO (divalent) at 1400 ° C. or higher, a large amount of clarified gas is released. Chloride decomposes and volatilizes in the temperature range of 1200 ° C or higher to generate clarified gas (chlorine gas, etc.), but particularly decomposes and volatilizes in a high temperature range of 1400 ° C or higher, generating a large amount of clarified gas. To do.
[0012]
By the SnO 2 and Sb 2 O 3 in combination with chloride thus as a refining agent, since the relatively wide high temperature region refining effect of low temperatures during vitrification reaction occurring over the time of homogenization melting hot is obtained, It is possible to obtain an alkali-free glass free from bubbles that cause display defects.
[0013]
Next, a method for producing the alkali-free glass of the present invention will be described.
[0014]
First, a glass raw material formulation is prepared so as to obtain a glass having a desired composition. The composition range of the glass and the reason for limitation will be described below.
[0015]
SiO 2 is a component that forms a glass network, and its content is 40 to 70%, preferably 45 to 65%. When the SiO 2 content is less than 40%, the chemical resistance is deteriorated, the strain point is lowered and the heat resistance is deteriorated. When the SiO 2 content is more than 70%, the high temperature viscosity is increased and the meltability is deteriorated, and the cristobalite is devitrified. Things are likely to precipitate.
[0016]
Al 2 O 3 is a component that enhances the heat resistance and devitrification resistance of the glass, and its content is 6 to 25%, preferably 10 to 20%. When the Al 2 O 3 content is less than 6%, the devitrification temperature is remarkably increased, and devitrification is likely to occur in the glass. Cloudiness tends to occur.
[0017]
B 2 O 3 is a component that acts as a flux and lowers the viscosity to facilitate melting, and its content is 5 to 20%, preferably 6 to 15%. When B 2 O 3 is less than 5%, the effect as a flux becomes insufficient, and when it is more than 20%, hydrochloric acid resistance is lowered, strain point is lowered and heat resistance is deteriorated.
[0018]
MgO is a component that lowers the high temperature viscosity without lowering the strain point and facilitates melting of the glass, and its content is 0 to 10%, preferably 0 to 7%. If MgO is more than 10%, the buffered hydrofluoric acid resistance of the glass is remarkably lowered. CaO also functions in the same manner as MgO, and its content is 0 to 15%, preferably 0 to 10%. When CaO is more than 15%, the buffered hydrofluoric acid resistance of the glass is remarkably lowered. BaO is a component that improves the chemical resistance of glass and improves devitrification, and its content is 0 to 30%, preferably 0 to 20%. When BaO is more than 30%, the strain point is lowered and the heat resistance is deteriorated. SrO has the same effect as BaO, and its content is 0 to 10%, preferably 0 to 7%. When SrO is more than 10%, devitrification increases, which is not preferable. ZnO is a component that improves buffered hydrofluoric acid resistance and improves devitrification, and its content is 0 to 10%, preferably 0 to 7%. If the ZnO content is more than 10%, the glass tends to be devitrified, and the strain point is lowered and heat resistance cannot be obtained. If the total amount of MgO, CaO, BaO, SrO and ZnO is less than 5%, the high-temperature viscosity becomes high and the meltability deteriorates, and the glass tends to devitrify. If it exceeds 30%, the heat resistance and acid resistance are high. Is not preferable.
[0019]
In addition to the above components, ZrO 2 , TiO 2 and the like can be added up to 5% in total.
[0020]
Then the SnO 2 and Sb 2 O 3 in the glass batch formulation is added chloride. As the chloride, BaCl 2 , CaCl 2 or the like can be used. With regard to the amount of addition of SnO 2 and Sb 2 O 3 content of a 0.05 to 2% by weight with respect to the glass raw material formulation 100% by weight and 0.05 to 1.2 wt%, with chlorides Cl 2 terms 0.01 to 2% by weight. If Sb 2 O 3 is less than 0.05%, it will be difficult to drive out the gas generated during the vitrification reaction. If SnO 2 is less than 0.05% and if the chloride content is less than 0.01%, homogenization melting will occur. Sometimes it becomes difficult to remove bubbles left in the glass melt. On the other hand, if SnO 2 is more than 2% and Sb 2 O 3 is more than 1.2 %, the glass tends to be devitrified, and if chloride is more than 2%, the volatilization amount becomes too large and the glass tends to deteriorate. .
[0021]
Subsequently, the prepared glass material is melted. When the glass raw material is heated, a vitrification reaction first occurs. At this time, oxygen gas is generated by a chemical reaction due to a change in the valence of Sb 2 O 3 , and the gas generated during the vitrification reaction is expelled from the melt. . Further, when homogenizing and melting at a higher temperature, oxygen gas is generated by a chemical reaction due to a change in the valence of SnO 2 , and chlorine gas is generated by decomposition and volatilization of chlorides, resulting in minute bubbles remaining in the glass melt. Is removed.
[0022]
Thereafter, the molten glass is formed into a desired shape. When used for display applications, it is formed into a thin plate using a fusion method, a downdraw method, a float method, a rollout method, or the like.
[0023]
In this manner, SiO 2 40 to 70% by weight percentage, Al 2 O 3 6~25%, B 2 O 3 5~20%, 0~10% MgO, CaO 0~15%, BaO 0~30% has SrO 0~10%, 0~10% ZnO, SnO 2 0.05~2%, Sb 2 O 3 0.05~ 1.2%, the composition of the Cl 2 0.005 to 1%, essentially Thus, the alkali-free glass of the present invention containing no alkali metal oxide can be obtained.
[0024]
【Example】
Hereinafter, the present invention will be described based on examples.
[0025]
Example 1
Table 1 shows the effects of SnO 2 , Sb 2 O 3 and chloride. Sample a is a conventional alkali-free glass to which As 2 O 3 is added as a fining agent, and sample b is from sample a to As 2. Alkali-free glass prepared by removing O 3 , sample c is alkali-free glass to which only SnO 2 is added, sample d is alkali-free glass to which only Sb 2 O 3 is added, and sample e is only chloride (BaCl 2 ). The added alkali-free glass, sample f, shows the alkali-free glass of the present invention in which SnO 2 , Sb 2 O 3 and chloride are used in combination.
[0026]
[Table 1]
[0027]
Each sample was prepared as follows.
[0028]
A glass raw material was prepared so as to be a glass raw material preparation having the composition shown in the table, and was melted in an electric furnace. At this time, two types were prepared: one melted at 1500 ° C. for 1 hour in order to evaluate the clarity during vitrification reaction and one melted at 1550 ° C. for 1 hour in order to evaluate the clarity during homogenization melting. . Next, the molten glass is poured on a carbon table and slowly cooled, and then the number of bubbles remaining in the glass is counted. When the number of bubbles in 100 g of glass exceeds 1000, x 101 to 1000 The ones were evaluated as Δ, 11 to 100 as ○, and 10 or less as ◎. The results are shown in Table 1. In addition, the glass raw material formulation composition in the table is a value in which each component is converted into an oxide, and chloride is a value in terms of Cl 2 .
[0029]
As apparent from Table 1, the clarity of the glass of sample b to which no clarifier was added was extremely poor. Sample c to which only SnO 2 was added generated a large amount of clarification gas during homogenization and melting, but the clarification during the vitrification reaction was insufficient, and as a result the sample to which As 2 O 3 was added The clarity was inferior to the glass of a. Similarly, the glass of sample e to which only chloride was added also produced a large amount of clarified gas during homogenization melting, but sufficient gas was not generated during the vitrification reaction, resulting in poor clarification. In the glass of sample d to which only Sb 2 O 3 was added, a large amount of clarification gas was generated during the vitrification reaction, but sufficient clarification gas was not generated during homogenization melting, resulting in poor clarification. On the other hand, the glass of sample f to which SnO 2 , Sb 2 O 3 and chloride were added had good clarity as the glass of sample a to which As 2 O 3 was added.
[0030]
(Example 2)
Tables 2 and 3 show examples (sample Nos. 1 to 7 ) of alkali-free glass obtained by the method of the present invention.
[0031]
[Table 2]
[0032]
[Table 3]
[0033]
Each sample was prepared as follows.
[0034]
Glass raw materials were prepared so that the glass had the composition shown in the table, and the clarity was evaluated in the same manner as in Example 1. Moreover, these glass raw material preparations were melted at 1550 to 1600 ° C. for 16 to 24 hours in an electric furnace and molded to obtain samples. BaCl 2 was used as the chloride. Each sample thus obtained was evaluated for heat resistance and chemical resistance. The results are shown in each table. Note the glass composition in the tables is a value obtained by converting oxides of each component, also a chloride is shown by a value Cl 2 converted the amount remaining in the glass.
[0035]
As is apparent from the table, each sample was excellent in clarity and heat resistance and chemical resistance.
[0036]
In addition, heat resistance measured the strain point based on the method of ASTM C336-71. The chemical resistance was evaluated by observing the surface state of the glass substrate after immersing each sample in hydrochloric acid aqueous solution of 10% by weight held at 80 ° C. for 24 hours, and changing the surface of the glass substrate. ×, no discoloration is indicated by ○. Buffered hydrofluoric acid resistance was determined by immersing each sample in buffered hydrofluoric acid composed of 38.7% by weight ammonium fluoride and 1.6% by weight hydrofluoric acid maintained at 20 ° C. for 30 minutes, and then the surface of the glass substrate. The state was evaluated by observing the state, and the case where the glass substrate surface became cloudy was indicated by x, and the case where the glass substrate surface did not change was indicated by ◯.
[0037]
【The invention's effect】
As described above, according to the method of the present invention, since SnO 2 , Sb 2 O 3 and chloride are used in combination as a clarifier, an alkali-free glass having excellent clarification and free of bubbles that cause display defects is produced. Is possible.
[0038]
In addition, the alkali-free glass of the present invention has no bubbles that cause display defects and has excellent heat resistance and chemical resistance, and is particularly suitable as a transparent glass substrate for display.
Claims (16)
Priority Applications (6)
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JP21579397A JP3897194B2 (en) | 1997-07-24 | 1997-07-24 | Alkali-free glass and method for producing the same |
US08/911,945 US6508083B1 (en) | 1996-08-21 | 1997-08-20 | Alkali-free glass and method for producing the same |
KR1019970039767A KR100406021B1 (en) | 1996-08-21 | 1997-08-21 | Alkali-free glass and method for producing the same |
US09/907,288 US6546753B2 (en) | 1996-08-21 | 2001-07-17 | Method of producing an alkali-free glass |
US10/298,811 US6933253B2 (en) | 1996-08-21 | 2002-11-18 | Alkali-free glass and method for producing the same |
KR1020030042403A KR100424420B1 (en) | 1996-08-21 | 2003-06-27 | Alkali-free glass and method for producing the same |
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US6468933B1 (en) * | 1998-09-22 | 2002-10-22 | Nippon Electric Glass Co., Ltd. | Alkali-free glass and method of producing the same |
CN1160268C (en) | 1998-11-30 | 2004-08-04 | 康宁股份有限公司 | Glasses for flat panel displays |
DE10084754B3 (en) * | 1999-06-29 | 2014-07-31 | Hoya Corp. | Glass substrate for use in a liquid crystal panel and its use and manufacture |
DE10000837C1 (en) | 2000-01-12 | 2001-05-31 | Schott Glas | Alkali-free alumino-borosilicate glass used as substrate glass in thin film transistor displays and thin layer solar cells contains oxides of silicon, boron, aluminum, magnesium, strontium, and barium |
DE10000836B4 (en) * | 2000-01-12 | 2005-03-17 | Schott Ag | Alkali-free aluminoborosilicate glass and its uses |
DE10034985C1 (en) * | 2000-07-19 | 2001-09-06 | Schott Glas | Production of an alkali-free aluminosilicate glass used as a substrate glass for displays comprises adding tin oxide as refining agent to the starting materials, melting the glass and hot molding the glass |
DE10064804C2 (en) * | 2000-12-22 | 2003-03-20 | Schott Glas | Alkali-free aluminoborosilicate glasses and their use |
JP4305817B2 (en) * | 2002-12-11 | 2009-07-29 | 日本電気硝子株式会社 | Alkali-free glass substrate |
JP2005053712A (en) * | 2003-08-04 | 2005-03-03 | Nippon Electric Glass Co Ltd | Alkali-free glass |
KR101399745B1 (en) | 2006-02-10 | 2014-05-26 | 코닝 인코포레이티드 | Glass composition having high thermal and chemical stability and methods of making thereof |
US8007913B2 (en) | 2006-02-10 | 2011-08-30 | Corning Incorporated | Laminated glass articles and methods of making thereof |
JP2009001491A (en) * | 2008-09-24 | 2009-01-08 | Nippon Electric Glass Co Ltd | Manufacturing method of non-alkali glass substrate |
US8713967B2 (en) | 2008-11-21 | 2014-05-06 | Corning Incorporated | Stable glass sheet and method for making same |
JPWO2013011980A1 (en) * | 2011-07-20 | 2015-02-23 | 旭硝子株式会社 | Method for producing float glass |
WO2016024962A1 (en) * | 2014-08-13 | 2016-02-18 | Corning Incorporated | Intermediate cte glasses and glass articles comprising the same |
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JP2871163B2 (en) * | 1991-04-26 | 1999-03-17 | 日本板硝子株式会社 | Alkali-free glass |
JP3247145B2 (en) * | 1992-04-28 | 2002-01-15 | 株式会社オハラ | Method for producing oxide-based glass and fluorine-containing glass |
US5374595A (en) * | 1993-01-22 | 1994-12-20 | Corning Incorporated | High liquidus viscosity glasses for flat panel displays |
JP3245516B2 (en) * | 1995-04-19 | 2002-01-15 | ホーヤ株式会社 | Optical glass |
DE19680967B3 (en) * | 1995-09-28 | 2012-03-01 | Nippon Electric Glass Co., Ltd. | Alkali-free glass substrate |
DE19680966T1 (en) * | 1995-09-28 | 1998-01-08 | Nippon Electric Glass Co | Alkali-free glass substrate |
US5824127A (en) * | 1996-07-19 | 1998-10-20 | Corning Incorporated | Arsenic-free glasses |
JP3861271B2 (en) * | 1996-08-21 | 2006-12-20 | 日本電気硝子株式会社 | Alkali-free glass and method for producing the same |
US5785726A (en) * | 1996-10-28 | 1998-07-28 | Corning Incorporated | Method of reducing bubbles at the vessel/glass interface in a glass manufacturing system |
JP4739468B2 (en) * | 1997-05-20 | 2011-08-03 | 旭硝子株式会社 | Alkali-free glass and its clarification method |
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