JP5396859B2 - Glass for information recording medium substrate - Google Patents
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- JP5396859B2 JP5396859B2 JP2008545441A JP2008545441A JP5396859B2 JP 5396859 B2 JP5396859 B2 JP 5396859B2 JP 2008545441 A JP2008545441 A JP 2008545441A JP 2008545441 A JP2008545441 A JP 2008545441A JP 5396859 B2 JP5396859 B2 JP 5396859B2
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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
- C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
- C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
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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
- C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
- C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
- C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73921—Glass or ceramic substrates
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- Engineering & Computer Science (AREA)
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- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Glass Compositions (AREA)
- Magnetic Record Carriers (AREA)
Description
本発明は、磁気ディスク用ガラス基板などの情報記録媒体用ガラス基板および情報記録媒体用ガラス基板に好適な情報記録媒体基板用ガラスに関する。 The present invention relates to a glass substrate for an information recording medium such as a glass substrate for a magnetic disk and a glass for an information recording medium substrate suitable for a glass substrate for an information recording medium.
情報記録媒体用基板、特に磁気ディスク(ハードディスク)用基板としてガラス基板が広く用いられており、磁気ディスク用ガラス基板としては化学強化されたものと化学強化されていないものが存在する。
化学強化されていない磁気ディスク用ガラス基板としては、SiO2−Al2O3−Li2O−Na2O−K2O−TiO2系ガラスからなるものが提案されている(特許文献1参照)。A glass substrate is widely used as an information recording medium substrate, particularly a magnetic disk (hard disk) substrate, and there are chemically strengthened and non-chemically strengthened glass substrates for magnetic disks.
As a glass substrate for a magnetic disk that is not chemically strengthened, a glass substrate made of SiO 2 —Al 2 O 3 —Li 2 O—Na 2 O—K 2 O—TiO 2 glass has been proposed (see Patent Document 1). ).
特許文献1のガラスはガラス転移点(Tg)が最高でも567℃であり、このガラスを磁気ディスク用ガラス基板に用いた場合、ガラス基板上に磁性層を形成する際の温度を高くすることができず、その結果磁性層の保磁力を大きくすることができないおそれがあるものであった。
本発明はこのような問題を解決できる、情報記録媒体基板用ガラスおよびこれを用いた情報記録媒体用ガラス基板の提供を目的とする。The glass of Patent Document 1 has a maximum glass transition point (Tg) of 567 ° C. When this glass is used for a glass substrate for a magnetic disk, the temperature at which a magnetic layer is formed on the glass substrate may be increased. As a result, the coercive force of the magnetic layer may not be increased.
An object of the present invention is to provide a glass for an information recording medium substrate and a glass substrate for an information recording medium using the same, which can solve such problems.
本発明は、下記酸化物基準のモル%表示で、SiO2を55〜75%、Al2O3を1〜12%、MgOを2〜15%、CaOを0〜1.5%、Na2OまたはK2Oを合計で1〜20%、TiO2を0〜8%含有し、BaOを含有する場合その含有量は2%以下であり、Li2Oを含有する場合その含有量は1%以下であり、ZrO2を含有する場合その含有量は0.5%以下である情報記録媒体基板用ガラスを提供する。
また、前記情報記録媒体基板用ガラスからなる情報記録媒体用ガラス基板を提供する。The present invention is expressed in terms of mol% based on the following oxides: SiO 2 is 55 to 75%, Al 2 O 3 is 1 to 12%, MgO is 2 to 15%, CaO is 0 to 1.5%, Na 2 The total content of O or K 2 O is 1 to 20%, the content of TiO 2 is 0 to 8%, and the content of BaO is 2% or less, and the content of Li 2 O is 1 or less. %, And when ZrO 2 is contained, the content of the glass for an information recording medium substrate is 0.5% or less.
Moreover, the glass substrate for information recording media which consists of said glass for information recording media substrates is provided.
本発明によれば、Tgが600℃以上である情報記録媒体基板用ガラスを得ることができる。
また、強度が高い、密度が小さい、またはフロート成形が可能な情報記録媒体基板用ガラスまたは情報記録媒体用ガラス基板を得ることができる。
また、耐候性が高い情報記録媒体用ガラス基板を得ることができるので、在庫中にガラス基板の表面性状が著しく変化し、前記基板上に形成される下地膜、磁性膜、保護膜等の膜がはがれやすくなるという問題が起こりにくくなる。
また、化学強化処理を行うことなく情報記録媒体用ガラス基板を製造できるので、工程を減らすことができ、また化学強化処理後の基板表面への汚れ付着の問題を解決できる。According to the present invention, a glass for an information recording medium substrate having a Tg of 600 ° C. or higher can be obtained.
Further, it is possible to obtain an information recording medium substrate glass or an information recording medium glass substrate having high strength, low density, or float forming.
In addition, since a glass substrate for an information recording medium having high weather resistance can be obtained, the surface properties of the glass substrate change remarkably during inventory, and films such as a base film, a magnetic film, and a protective film formed on the substrate. The problem of easy peeling is less likely to occur.
Moreover, since the glass substrate for information recording media can be manufactured without performing the chemical strengthening treatment, the number of processes can be reduced, and the problem of dirt adhesion to the substrate surface after the chemical strengthening treatment can be solved.
本発明の情報記録媒体基板用ガラス(以下、本発明のガラスという。)のTgは600℃以上であることが好ましい。600℃未満では磁性層形成熱処理温度を充分高くすることができず、磁性層の保磁力増加が困難になるおそれがある。より好ましくは610℃以上、特に好ましくは620℃以上である。 The Tg of the glass for an information recording medium substrate of the present invention (hereinafter referred to as the glass of the present invention) is preferably 600 ° C. or higher. If it is less than 600 ° C., the heat treatment temperature for forming the magnetic layer cannot be sufficiently increased, and it may be difficult to increase the coercive force of the magnetic layer. More preferably, it is 610 degreeC or more, Most preferably, it is 620 degreeC or more.
本発明のガラスの50〜350℃における平均線膨張係数(α)は70×10−7/℃以上であることが好ましい。70×10−7/℃未満では、基板に取り付けるハブの金属の熱膨張係数(典型的には70×10−7〜100×10−7/℃)との差が大きくなり、基板の割れが起こりやすくなる。より好ましくは75×10−7/℃以上、特に好ましくは80×10−7/℃以上である。また、αは典型的には95×10−7/℃以下である。It is preferable that the average linear expansion coefficient ((alpha)) in 50-350 degreeC of the glass of this invention is 70x10 < -7 > / degreeC or more. If it is less than 70 × 10 −7 / ° C., the difference between the thermal expansion coefficient of the metal of the hub attached to the substrate (typically 70 × 10 −7 to 100 × 10 −7 / ° C.) becomes large, and the substrate cracks. It tends to happen. More preferably, it is 75 × 10 −7 / ° C. or more, and particularly preferably 80 × 10 −7 / ° C. or more. Α is typically 95 × 10 −7 / ° C. or less.
本発明のガラスは、その液相温度をTLとし、粘度が104P(ポアズ)となる温度をT4とした場合、(TL−T4)は50℃未満であることが好ましい。(TL−T4)が50℃以上ではフロート成形が困難になるおそれがあり、より好ましくは40℃未満、特に好ましくは30℃未満である。
本発明のガラスの粘度が102Pとなる温度T2は1700℃以下であることが好ましい。T2が1700℃超ではガラスの溶解または清澄が困難になるおそれがある。In the glass of the present invention, when the liquidus temperature is TL and the temperature at which the viscosity is 10 4 P (poise) is T 4 , ( TL- T 4 ) is preferably less than 50 ° C. If (T L -T 4 ) is 50 ° C. or higher, float molding may be difficult, more preferably less than 40 ° C., and particularly preferably less than 30 ° C.
The temperature T 2 at which the viscosity of the glass of the present invention becomes 10 2 P is preferably 1700 ° C. or lower. If T 2 exceeds 1700 ° C., it may be difficult to dissolve or clarify the glass.
磁気ディスク用ガラス基板はノートブックパソコン等に用いられる2.5インチ基板(ガラス基板外径:65mm)やポータブルMP3プレーヤなどに用いられる1.8インチ基板(ガラス基板外径:48mm)などに広く使用され、その市場は年々拡大しており、一方で低価格での供給が求められている。このようなガラス基板に使用されるガラスは、大量生産に適したものであることが好ましい。
板ガラスの大量生産はフロート法、フュージョン法、ダウンドロー法などの連続成形法により広く行われており、本発明のガラスは先に述べたように、たとえばフロート成形が可能なガラスとできるので大量生産に好適である。Glass substrates for magnetic disks are widely used for 2.5 inch substrates (outer diameter of glass substrate: 65 mm) used for notebook personal computers and 1.8 inch substrates (outer diameter of glass substrate: 48 mm) used for portable MP3 players, etc. The market is growing year by year, while low-cost supply is required. It is preferable that the glass used for such a glass substrate is suitable for mass production.
Mass production of sheet glass is widely performed by continuous molding methods such as the float method, fusion method, and downdraw method. As described above, the glass of the present invention can be produced in large quantities because it can be made, for example, glass that can be float molded. It is suitable for.
本発明のガラスの密度は2.50g/cm3以下であることが好ましく、より好ましくは2.48g/cm3以下、特に好ましくは2.47g/cm3以下である。Preferably the density of the glass of the present invention is 2.50 g / cm 3 or less, more preferably 2.48 g / cm 3 or less, particularly preferably 2.47 g / cm 3 or less.
本発明の情報記録媒体用ガラス基板(以下、本発明のガラス基板という。)は本発明のガラスからなる、通常は円形のガラス板である。なお、情報記録媒体としては磁気ディスクが例示される。 The glass substrate for information recording media of the present invention (hereinafter referred to as the glass substrate of the present invention) is a generally circular glass plate made of the glass of the present invention. An example of the information recording medium is a magnetic disk.
本発明のガラス基板は、それを120℃、2気圧の水蒸気雰囲気に20時間保持したとき、その表面に存在する、大きさが10μm以上の付着物の数NLが1個/cm2以下である、または、大きさが1μm以上10μm未満の付着物の数NSが105個/cm2以下であることが好ましい。NLが1個/cm2超またはNSが105個/cm2超では、ガラス基板在庫中にガラス基板表面に付着物(白ヤケ)が発生し、ガラス基板上に形成される下地膜、磁性膜、保護膜等の膜がはがれやすくなる。この付着物は、空気中の水分や炭酸ガスの影響によりガラス基板に生成付着した反応生成物であると考えられ、拭いても除去できないものである。NLはより好ましくは0.8個/cm2以下、特に好ましくは0.5個/cm2以下である。NSはより好ましくは0.8×105個/cm2以下、特に好ましくは0.6×105個/cm2以下である。When the glass substrate of the present invention is held in a steam atmosphere at 120 ° C. and 2 atm for 20 hours, the number N L of deposits having a size of 10 μm or more present on the surface is 1 piece / cm 2 or less. or, it is preferable that the size adheres the number N S of less than 10μm or 1μm is 10 5 / cm 2 or less. The N L is 1 / cm 2 or greater than N S 10 5 cells / cm 2, greater than the base film which deposits on the surface of the glass substrate in the glass substrate stock (dimming) is generated, are formed on a glass substrate In addition, films such as magnetic films and protective films are easily peeled off. This deposit is considered to be a reaction product produced and adhered to the glass substrate due to the influence of moisture and carbon dioxide in the air, and cannot be removed by wiping. N L is more preferably 0.8 pieces / cm 2 or less, particularly preferably 0.5 pieces / cm 2 or less. N S is more preferably 0.8 × 10 5 / cm 2 or less, particularly preferably 0.6 × 10 5 / cm 2 or less.
本発明のガラスのクラック発生率は70%以下であることが好ましい。70%超ではガラス強度が不十分となる可能性がある。より好ましくは60%以下、特に好ましくは50%以下である。
前記クラック発生率は次のようにして求められる。すなわち、23℃、相対湿度70%に制御した室内において、厚さが1〜2mm、大きさが4cm×4cmの鏡面研磨したガラス板の表面に荷重500gでビッカース圧子を打ち込み、その4つの頂点から発生するクラック本数を測定する。この測定を10回繰り返し、100×(発生したクラック総本数)/40をクラック発生率とする。
クラック発生率が小さいものはガラス表面にキズがつきにくいので応力集中が発生しにくく、弱い応力で脆性的破壊が起こることがなくなる、または減少する。The crack occurrence rate of the glass of the present invention is preferably 70% or less. If it exceeds 70%, the glass strength may be insufficient. More preferably, it is 60% or less, and particularly preferably 50% or less.
The crack occurrence rate is obtained as follows. That is, in a room controlled at 23 ° C. and a relative humidity of 70%, a Vickers indenter is driven with a load of 500 g on the surface of a mirror-polished glass plate having a thickness of 1 to 2 mm and a size of 4 cm × 4 cm. Measure the number of cracks generated. This measurement is repeated 10 times, and 100 × (total number of cracks generated) / 40 is defined as the crack occurrence rate.
When the crack generation rate is small, the glass surface is hardly scratched, so that stress concentration is difficult to occur, and brittle fracture does not occur or is reduced by weak stress.
本発明のガラスおよびガラス基板の製造方法は特に限定されず、各種方法を適用できる。たとえば、通常使用される各成分の原料を目標組成となるように調合し、これをガラス溶融窯で加熱溶融する。バブリング、撹拌、清澄剤の添加等によりガラスを均質化し、周知のフロート法、プレス法、フュージョン法またダウンドロー法などの方法により所定の厚さの板ガラスに成形し、徐冷後必要に応じて研削、研磨などの加工を行った後、所定の寸法・形状のガラス基板とされる。成形法としては、特に、大量生産に適したフロート法が好適である。また、フロート法以外の連続成形法、すなわち、フュージョン法、ダウンドロー法も好適である。 The method for producing the glass and glass substrate of the present invention is not particularly limited, and various methods can be applied. For example, the raw materials of each component normally used are prepared so as to have a target composition, and this is heated and melted in a glass melting kiln. Homogenize the glass by bubbling, stirring, adding a clarifying agent, etc., and forming it into a sheet glass of a predetermined thickness by methods such as the well-known float method, press method, fusion method or down draw method, and after slow cooling, as necessary After processing such as grinding and polishing, a glass substrate having a predetermined size and shape is obtained. As the molding method, a float method suitable for mass production is particularly suitable. Further, continuous molding methods other than the float method, that is, the fusion method and the downdraw method are also suitable.
次に、本発明のガラスの組成についてモル%表示を用いて説明する。
SiO2はガラスの骨格を形成する成分であり、必須である。55%未満では、ガラスにキズが付きやすくなる、またTLが上昇しガラスが不安定になる。好ましくは58%以上、より好ましくは60%以上、特に好ましくは62%以上、典型的には64%以上、より典型的には65%以上である。75%超では、高温粘性が上昇しガラスの溶解が困難となる。好ましくは72%以下、より好ましくは71%以下である。Next, the composition of the glass of the present invention will be described using mol% display.
SiO 2 is a component that forms a glass skeleton and is essential. If it is less than 55%, the glass tends to be scratched, and the TL rises and the glass becomes unstable. Preferably it is 58% or more, more preferably 60% or more, particularly preferably 62% or more, typically 64% or more, more typically 65% or more. If it exceeds 75%, the high-temperature viscosity rises and it becomes difficult to melt the glass. Preferably it is 72% or less, More preferably, it is 71% or less.
Al2O3はTgを高くし、耐候性を高める効果を有し、必須である。1%未満では前記効果が小さい。好ましくは1.5%以上、より好ましくは2%以上、特に好ましくは2.5%以上である。12%超では高温粘性が上昇しガラスの溶解が困難となり、またTLが高くなりすぎる。好ましくは10%以下、より好ましくは8%以下、特に好ましくは7%以下、典型的には6.5%以下である。Al 2 O 3 has an effect of increasing Tg and improving weather resistance, and is essential. If it is less than 1%, the effect is small. Preferably it is 1.5% or more, More preferably, it is 2% or more, Most preferably, it is 2.5% or more. If it exceeds 12%, the high-temperature viscosity will increase, making it difficult to melt the glass, and TL will be too high. It is preferably 10% or less, more preferably 8% or less, particularly preferably 7% or less, and typically 6.5% or less.
MgOは、耐候性を維持したままαを大きくする、ガラスを傷つきにくくする、またガラスの溶解性を向上させる効果があり必須成分である。2%未満では前記効果が小さい。好ましくは5%以上、より好ましくは7%以上、最も好ましくは8%以上である。15%超ではTLが高くなりすぎる。好ましくは14%以下、より好ましくは13%以下である。 MgO is an essential component with the effect of increasing α while maintaining the weather resistance, making the glass less susceptible to damage, and improving the solubility of the glass. If it is less than 2%, the effect is small. Preferably it is 5% or more, more preferably 7% or more, and most preferably 8% or more. If it exceeds 15%, the TL becomes too high. Preferably it is 14% or less, More preferably, it is 13% or less.
CaOは必須ではないが、耐候性を維持したままαを大きくする、またはガラスの溶解性を向上させるために1.5%まで含有してもよい。1.5%超ではガラスが傷つきやすくなるおそれがある。好ましくは1%以下、より好ましくは0.5%未満、典型的には0.3%以下である。 CaO is not essential, but may be contained up to 1.5% in order to increase α while maintaining the weather resistance or to improve the solubility of the glass. If it exceeds 1.5%, the glass may be easily damaged. Preferably it is 1% or less, more preferably less than 0.5%, typically 0.3% or less.
Na2OおよびK2Oはαを大きくする、またガラスの溶解性を向上させる効果を有する成分であり、少なくともいずれかを含有しなければならない。Na2OおよびK2Oの含有量の合計Na2O+K2Oが1%未満では前記効果が小さい。好ましくは2%超、より好ましくは5%以上、特に好ましくは7%以上、典型的には10%以上である。20%超では耐候性が低下し、ガラス転移点が低下する。好ましくは17%以下、より好ましくは15%以下、特に好ましくは14%以下、典型的には13.5%以下である。典型的にはNa2Oが2〜8%、K2Oが3〜10%である。
SiO2が60%超、Al2O3が10%以下、Na2O+K2Oが2%超17%以下であることが好ましい。Na 2 O and K 2 O are components having an effect of increasing α and improving the solubility of glass, and must contain at least one of them. The effect is small when the total Na 2 O + K 2 O content of Na 2 O and K 2 O is less than 1%. It is preferably more than 2%, more preferably 5% or more, particularly preferably 7% or more, and typically 10% or more. If it exceeds 20%, the weather resistance is lowered and the glass transition point is lowered. It is preferably 17% or less, more preferably 15% or less, particularly preferably 14% or less, and typically 13.5% or less. Typically, Na 2 O is 2 to 8% and K 2 O is 3 to 10%.
It is preferable that SiO 2 is more than 60%, Al 2 O 3 is 10% or less, and Na 2 O + K 2 O is more than 2% and 17% or less.
TiO2は必須成分ではないが、Tgを高くする、耐候性を高くする、またはガラスの溶解性を向上させる効果があり、8%まで含有してもよい。8%超ではTLが高くなりすぎるおそれがある、または分相現象が起りやすくなるおそれがある。好ましくは7%以下、より好ましくは6%以下、特に好ましくは5%以下である。また、TiO2を含有する場合、その含有量は1%以上であることが好ましい。より好ましくは1.5%以上、特に好ましくは2%以上、最も好ましくは3%以上である。
MgOおよびTiO2の含有量の合計MgO+TiO2は10%以上であることが好ましい。10%未満ではガラスが傷つきやすくなるおそれがある、または高温粘性が上昇しガラスの溶解が困難になるおそれがある。MgO+TiO2は典型的には13%以上である。
典型的には、SiO2は62〜72%、Al2O3は2〜8%、MgOは7〜14%、Na2O+K2Oは10〜14%、TiO2は0〜6%である。TiO 2 is not an essential component, but has the effect of increasing Tg, increasing weather resistance, or improving glass solubility, and may be contained up to 8%. If it exceeds 8%, TL may be too high, or a phase separation phenomenon may easily occur. Preferably it is 7% or less, More preferably, it is 6% or less, Most preferably, it is 5% or less. Further, when containing TiO 2, its content is preferably at least 1%. More preferably, it is 1.5% or more, particularly preferably 2% or more, and most preferably 3% or more.
The total MgO + TiO 2 content of MgO and TiO 2 is preferably 10% or more. If it is less than 10%, the glass may be easily damaged, or the high-temperature viscosity may increase and it may be difficult to melt the glass. MgO + TiO 2 is typically at least 13%.
Typically, SiO 2 is 62~72%, Al 2 O 3 is 2 to 8%, MgO is 7~14%, Na 2 O + K 2 O is 10 to 14%, TiO 2 is 6% .
本発明のガラスは本質的に上記成分からなるが、本発明の目的を損なわない範囲でその他の成分を含有してもよい。その場合、当該他の成分の含有量の合計は好ましくは10%以下、より好ましくは5%以下、典型的には2%以下である。
たとえばSO3、Cl、As2O3、Sb2O3、SnO2等の清澄剤を合計で2%まで含有してもよいが、As2O3、Sb2O3、SnO2は含有しないことが好ましい。
また、ガラスの溶解性や安定性を向上させるためにB2O3を合計で3%まで含有してもよい。
ただし、次のような観点からはB2O3は実質的に含有しないことが好ましい。すなわち、B2O3はアルカリ金属酸化物成分と共存すると蒸気圧の低いアルカリボレート化合物を形成しやすくなってガラス融液から同成分が非常に揮散しやすくなる。これにより脈理などの不均質が発生しガラス品質低下を引き起こすと同時に、揮散物がガラス溶融窯に使用されているれんが物質に凝縮し、れんが強度を著しく低下させる、揮散物の回収処理に莫大な費用がかかる、等の問題が発生するため、このような問題の発生を抑制したい場合にはB2O3を実質的に含有しないことが好ましい。The glass of the present invention consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. In that case, the total content of the other components is preferably 10% or less, more preferably 5% or less, and typically 2% or less.
For example, clarifiers such as SO 3 , Cl, As 2 O 3 , Sb 2 O 3 and SnO 2 may be contained up to 2% in total, but As 2 O 3 , Sb 2 O 3 and SnO 2 are not contained. It is preferable.
It may also be contained in order to improve the solubility and stability of the glass up to 3% B 2 O 3 in total.
However, B 2 O 3 is from the following viewpoints are preferably substantially free. That is, when B 2 O 3 coexists with an alkali metal oxide component, it tends to form an alkali borate compound having a low vapor pressure, and the same component is very easily volatilized from the glass melt. This causes inhomogeneities such as striae and causes glass quality deterioration, and at the same time, the volatilized material is condensed into the brick material used in the glass melting kiln, which significantly reduces the strength of the volatilized material. Therefore, it is preferable that B 2 O 3 is not substantially contained when it is desired to suppress the occurrence of such a problem.
SrOまたはBaOを、耐候性を維持したままαを大きくする、またガラスの溶解性を向上させるために合計で4%以下の範囲で含有してもよい場合がある。4%超ではガラスが傷つきやすくなるおそれがある。好ましくは2%以下である。ただし、BaOを含有する場合その含有量は2モル%以下としなければならない。
なお、ガラスをより傷つきにくくしたい場合などにはSrOは含有しないか、含有する場合でも0.1%未満であることが好ましい。また、このような場合にはBaOは含有しないか、含有する場合でも0.1%未満であることが好ましい。
αを大きくする、またはガラスの溶解性を向上させるためにLi2Oを1%まで含有してもよい。1%超ではTgが低くなる、耐候性が低下する、またはガラスが傷つきやすくなる。典型的には0.6%以下であるが、実質的に含有しないことが多くの場合好ましい。
Tgを高くするためにZrO2を0.5%まで含有してもよい。0.5%超ではガラスが傷つきやすくなる。In some cases, SrO or BaO may be contained within a total range of 4% or less in order to increase α while maintaining the weather resistance and to improve the solubility of the glass. If it exceeds 4%, the glass may be easily damaged. Preferably it is 2% or less. However, when it contains BaO, the content must be 2 mol% or less.
In addition, when it is desired to make the glass more difficult to be damaged, SrO is not contained, or even if it is contained, it is preferably less than 0.1%. In such a case, BaO is not contained, or even if contained, it is preferably less than 0.1%.
Li 2 O may be contained up to 1% in order to increase α or improve the solubility of glass. If it exceeds 1%, the Tg is lowered, the weather resistance is lowered, or the glass is easily damaged. Typically, it is 0.6% or less, but it is often preferable not to contain it substantially.
In order to increase Tg, ZrO 2 may be contained up to 0.5%. If it exceeds 0.5%, the glass tends to be damaged.
CaO、SrOまたはBaOを含有する場合、MgO含有量と(MgO、CaO、SrOおよびBaOの各含有量合計)とのモル比:(MgO)/(MgO+CaO+SrO+BaO)は0.6以上であることが好ましい。0.6未満ではガラスが傷つきやすくなる。 When CaO, SrO or BaO is contained, the molar ratio of MgO content to (total content of MgO, CaO, SrO and BaO): (MgO) / (MgO + CaO + SrO + BaO) is preferably 0.6 or more. . If it is less than 0.6, the glass tends to be damaged.
Li2O、Na2OおよびK2Oの各含有量の合計をR’2Oとし、アルカリ土類金属酸化物の含有量の合計をROとして、R’2Oと(R’2O+RO)とのモル比、すなわち、(R’2O)/(R’2O+RO)は0.25〜0.75であることが好ましい。この範囲外では、耐候性が低下する、αが小さくなる、またはガラスが傷つきやすくなるおそれがある。より好ましくは0.3〜0.7である。
K2Oを含有する場合、K2O含有量とLi2O、Na2OおよびK2Oの各含有量の合計とのモル比、すなわち、K2O/(Li2O+Na2O+K2O)は0.2以上であることが好ましい。0.2未満ではTgが低くなる、または耐候性が低下するおそれがある。より好ましくは0.3以上、特に好ましくは0.4以上である。
Tiよりも原子番号が大きな原子(Vなど)の酸化物はガラスを傷つきやすくするおそれがあるので、これらを含有する場合にはそれらの含有量の合計は0.5%以下であることが好ましい。より好ましくは0.3%以下、特に好ましくは0.2%以下、最も好ましくは0.1%以下である。The total content of Li 2 O, Na 2 O and K 2 O is R ′ 2 O, the total content of alkaline earth metal oxides is RO, and R ′ 2 O and (R ′ 2 O + RO) the molar ratio of, i.e., (R '2 O) / (R' 2 O + RO) is preferably 0.25 to 0.75. Outside this range, the weather resistance may be reduced, α may be small, or the glass may be easily damaged. More preferably, it is 0.3-0.7.
When containing K 2 O, K 2 O content and Li 2 O, molar ratio of the sum of the content of Na 2 O and K 2 O, i.e., K 2 O / (Li 2 O + Na 2 O + K 2 O ) Is preferably 0.2 or more. If it is less than 0.2, Tg may be lowered, or the weather resistance may be lowered. More preferably, it is 0.3 or more, and particularly preferably 0.4 or more.
Since oxides of atoms having atomic numbers larger than Ti (such as V) may easily damage the glass, when these are contained, the total content thereof is preferably 0.5% or less. . More preferably, it is 0.3% or less, particularly preferably 0.2% or less, and most preferably 0.1% or less.
各成分の原料を「表」中のSiO2からZrO2までの欄にモル%表示で示した組成となるように調合し、白金るつぼを用いて1550〜1600℃の温度で3〜5時間溶解した。溶解にあたっては、白金スターラを溶融ガラス中に挿入し、2時間撹拌してガラスを均質化した。次いで溶融ガラスを流し出して板状に成形し、徐冷した。なお、「表」中のROは、MgO、CaO、SrOおよびBaOの含有量(単位:モル%)の合計、R’2Oは、Li2O、Na2OおよびK2Oの含有量(単位:モル%)の合計を示している。
例1〜11のガラスは実施例であり、例12〜25のガラスは比較例である。The raw materials of each component were prepared so as to have a composition expressed in mol% in the columns from SiO 2 to ZrO 2 in the “Table”, and dissolved at a temperature of 1550 to 1600 ° C. for 3 to 5 hours using a platinum crucible. did. In melting, a platinum stirrer was inserted into the molten glass and stirred for 2 hours to homogenize the glass. Next, the molten glass was poured out, formed into a plate shape, and gradually cooled. In Tables, RO is the total content of MgO, CaO, SrO and BaO (unit: mol%), and R ′ 2 O is the content of Li 2 O, Na 2 O and K 2 O ( (Unit: mol%).
The glass of Examples 1-11 is an Example, The glass of Examples 12-25 is a comparative example.
こうして得られたガラス板について、クラック発生率(単位:%)、ガラス転移点Tg(単位:℃)、熱膨張係数α(単位:×10−7/℃)、液相温度TL(単位:℃)、粘度が104Pとなる温度T4(単位:℃)、粘度が102Pとなる温度T2(単位:℃)、前記NL(単位:個/cm2)、前記NS(単位:105個/cm2)、および密度(単位:g/cm3)を測定した。結果を「表」中に、Tg、α、TL、T4、T2、NL、NSの測定方法を以下にそれぞれ示す。なお、「表」中の「−」で示す項目は測定しなかった。
Tg:示差熱膨張計を用いて、石英ガラスを参照試料として室温から5℃/分の割合で昇温した際のガラスの伸び率を、ガラスが軟化してもはや伸びが観測されなくなる温度、すなわち屈伏点まで測定し、得られた熱膨張曲線における屈曲点に相当する温度をガラス転移点とした。About the glass plate obtained in this way, crack generation rate (unit:%), glass transition point Tg (unit: ° C.), thermal expansion coefficient α (unit: × 10 −7 / ° C.), liquidus temperature T L (unit: ° C.), the temperature T 4 at which the viscosity becomes 10 4 P (unit: ° C.), the temperature T 2 (unit viscosity becomes 10 2 P: ℃), wherein N L (unit: pieces / cm 2), said N S (Unit: 10 5 pieces / cm 2 ) and density (unit: g / cm 3 ) were measured. The results in "table" indicates Tg, α, T L, T 4, T 2, N L, the N S measurement methods below, respectively. In addition, the item shown by "-" in a "table" was not measured.
Tg: Using a differential thermal dilatometer, the elongation rate of the glass when the temperature is raised from room temperature at a rate of 5 ° C./minute using quartz glass as a reference sample is the temperature at which the glass softens and no longer can be observed. Measurement was made up to the yield point, and the temperature corresponding to the inflection point in the obtained thermal expansion curve was taken as the glass transition point.
α:示差熱膨張計を用いて、石英ガラスを参照試料として室温から5℃/分の割合で昇温した際のガラスの伸び率を、屈伏点まで測定し、得られた熱膨張曲線から50〜350℃における平均線膨張係数を算出した。 α: Using a differential thermal dilatometer, the elongation of the glass was measured from quartz glass as a reference sample at a rate of 5 ° C./min from room temperature to the yield point. The average linear expansion coefficient at ˜350 ° C. was calculated.
TL:ガラスを乳鉢で2mm程度のガラス粒に粉砕し、このガラス粒を白金ボートに並べて置き、温度傾斜炉中で24時間熱処理した。結晶が析出しているガラス粒の温度の最高値を液相温度とした。
T4、T2:回転粘度計により測定した。T L : The glass was crushed into glass particles of about 2 mm with a mortar, and these glass particles were placed side by side on a platinum boat and heat-treated in a temperature gradient furnace for 24 hours. The maximum value of the temperature of the glass grains on which the crystals were precipitated was taken as the liquidus temperature.
T 4 , T 2 : Measured with a rotational viscometer.
NL、NS:厚さが1〜2mm、大きさが4cm×4cmのガラス板の両面を鏡面研磨し、炭酸カルシウムおよび中性洗剤を用いて洗浄した後、超加速寿命試験器(不飽和型プレッシャークッカーTPC−410、タバイエスペック(株))に入れて120℃、2気圧の水蒸気雰囲気に20時間静置した。取り出したガラス板の表面200μm角の範囲を微分干渉顕微鏡で観察し、大きさが10μm以上の付着物の個数と大きさが1μm以上10μm未満の付着物の個数をカウントした。N L , N S : Both sides of a glass plate having a thickness of 1 to 2 mm and a size of 4 cm × 4 cm are mirror-polished, washed with calcium carbonate and a neutral detergent, and then a super accelerated life tester (unsaturated) Was placed in a mold pressure cooker TPC-410, Tabai Espec Co., Ltd.) and allowed to stand in a steam atmosphere at 120 ° C. and 2 atmospheres for 20 hours. The surface of the surface of the glass plate taken out was observed with a differential interference microscope, and the number of deposits having a size of 10 μm or more and the number of deposits having a size of 1 μm or more and less than 10 μm were counted.
磁気ディスク基板等の情報記録媒体基板、磁気ディスク等の情報記録媒体の製造に利用できる。
なお、2006年11月22日に出願された日本特許出願2006−315122号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。It can be used for manufacturing information recording medium substrates such as magnetic disk substrates and information recording media such as magnetic disks.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2006-315122 filed on November 22, 2006 are cited herein as disclosure of the specification of the present invention. Incorporated.
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JP5614607B2 (en) * | 2008-08-04 | 2014-10-29 | 日本電気硝子株式会社 | Tempered glass and method for producing the same |
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