JP2009203154A - Glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain glass having both low thermally expandable property and low temperature melting property, in which average linear expansion coefficient at 0-300°C lies in the range of 25-55×10<SP>-7</SP>°C<SP>-1</SP>preferably, and which can be produced at melting temperature of preferably at ≤1,450°C, and further preferably at ≤1,400°C. <P>SOLUTION: The glass includes the average linear expansion coefficient of 25-55×10<SP>-7</SP>°C<SP>-1</SP>at 0-300°C and contains Al<SB>2</SB>O<SB>3</SB>component and MgO component based on oxide and the ratio of Al<SB>2</SB>O<SB>3</SB>/MgO expressed by mass% exceeds >0.57. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-resistant glass and a glass having a low average linear expansion coefficient useful as various substrate materials.

  Glass having a low average linear expansion coefficient is used in a wide range of fields such as a substrate material and a heat-resistant glass in the field of precision equipment as described in Patent Document 1, and a substrate material for a display if it is non-alkali. .

Borosilicate glass is commonly known as a low thermal expansion glass. A typical example is Corning # 7740, which has an average coefficient of linear expansion of 32.5 × 10 ⁻⁷ ° C. ⁻¹ at ⁰ to 300 ° C.

However, such a glass having low thermal expansion generally has a high SiO ₂ content, and the melting temperature of the glass raw material when producing the glass is as high as 1500 ° C. or higher.

  Therefore, in the production of such glass, there are problems that workability is reduced, the cost of manufacturing equipment is increased, and the maintenance cost of manufacturing equipment is increased.

  And if the meltability of glass is improved in order to solve such problems, the average linear expansion coefficient tends to increase. In general, low thermal expansibility and low-temperature meltability are contradictory in the physical properties of glass, and it has been difficult to develop a glass having these two characteristics.

  On the other hand, glass with low thermal expansion is in demand in a wide range of fields, especially in recent years, because of the development of liquid crystal and plasma display substrate fields, development of glass that can be manufactured at low cost that combines low thermal expansion and low-temperature melting. Was desired.

In Patent Document 2, as a glass for a liquid crystal display, the average linear expansion coefficient at 30 to 380 ° C. is 33 to 49 (× 10 ⁻⁷ ° C. ⁻¹ ), and the viscosity is 10 ^2.5 poise which is the high temperature viscosity of the glass. Although a glass having a corresponding temperature of 1499 ° C. to 1595 ° C. is disclosed, the embodiment having a relatively low average linear expansion coefficient has a high temperature, and the embodiment of the glass having both low thermal expansion and low temperature melting is Not disclosed.
JP-A-60-141642 JP 2001-261366 A

An object of the present invention is to provide a glass having both a low thermal expansion and low-temperature fusibility is the average linear expansion coefficient of 25~55 × 10 ^-7 ℃ ^-1 at 0 ° C. to 300 ° C., further requests A property that can be achieved is to provide a glass that can be produced at a melting temperature of 1450 ° C. or lower, more preferably 1400 ° C. or lower.

The melting temperature of the glass raw material (also simply referred to as the melting temperature) is an index of low-temperature melting property, and when the raw material is heated to form a melt, the temperature at which the viscosity becomes 10 ^2.5 dPa · s. Say. The measurement can be performed using a ball pulling-up type viscometer, for example, using BVM-13LH manufactured by Opto Corporation.

  The average linear expansion coefficient is an indicator of low thermal expansion, and the temperature range is 0 ° C. according to JOGIS (Japan Optical Glass Industry Association Standard) 16-2003 “Measurement Method of Average Linear Expansion Coefficient of Optical Glass Near Room Temperature”. To the value measured in the range of 300 ° C to 300 ° C.

For solving the above problems, the present inventors have SiO ₂ component include _Al 2 _{O 3} component and MgO component, SiO ₂ component in terms of% by mass on the oxide basis, the sum of _Al 2 _{O 3} component and MgO component 80 Glass having an Al ₂ O ₃ / MgO ratio of more than 0.57 and more than 0.57 having an average linear expansion coefficient from 0 ° C. to 300 ° C. of 25 to 55 × 10 ⁻⁷ ° C. ^−1. I found it. Further, this glass contains a lot of glass that can be produced at a melting temperature of preferably 1450 ° C. or less, more preferably 1400 ° C. or less when the viscosity of the glass raw material is 10 ^2.5 dPa · s. More specifically, the present invention provides the following.

Configuration 1
It contains SiO ₂ component, Al ₂ O ₃ component and MgO component on oxide basis, and the total of SiO ₂ component, Al ₂ O ₃ component and MgO component exceeds 80% by mass% on oxide basis, Al ₂ O ₃ A glass characterized in that the mass ratio Al ₂ O ₃ / MgO between the component and the MgO component exceeds 0.57, and the average linear expansion coefficient at 0 to 300 ° C. is 25 to 55 × 10 ⁻⁷ ° C. ⁻¹ .

Configuration 2
The glass of constitution 1 comprising 50 to 65% of a SiO ₂ component in mass% based on oxide.

Configuration 3
The glass of constitution 1 or 2, comprising 8 to 25% of an Al ₂ O ₃ component, 10 to 20% of an MgO component, and 1 to 10% of a B ₂ O ₃ component by mass% based on an oxide.

Configuration 4
0 to 5% of CaO ₂ component and / or 0 to 5% of BaO component and / or 0 to 5% of ZrO ₂ component and / or 0 to 10% of Li ₂ O component in mass% based on oxide, and The glass according to any one of constitutions 1 to 3, comprising 0 to 10% of a Na ₂ O component and / or 0 to 10% of a K ₂ O component.

Configuration 5
The glass according to any one of the constitutions 1 to 4, comprising 0 to 1% of an As ₂ O ₃ component and / or an Sb ₂ O ₃ component in an oxide-based mass%.

Configuration 6
The glass according to any one of the constitutions 1 to 5, wherein the temperature when the viscosity of the glass exhibits 10 ^2.5 dPa · s is 1450 ° C. or lower.

Configuration 7
The glass according to any one of the constitutions 1 to 6, wherein the glass exhibits a first grade or a second grade in the powder method water resistance and the powder method acid resistance defined by the Japan Optical Glass Industry Association Standard (JOGIS).

ADVANTAGE OF THE INVENTION According to this invention, the glass which has low-temperature expansion property and low temperature meltability as a more preferable characteristic can be provided. That is, the average linear expansion coefficient at 0 ° C. to 300 ° C. is preferably 25 to 55 × 10 ⁻⁷ ° C. ⁻¹ , and the melting temperature when the viscosity of the glass raw material is 10 ^2.5 dPa · s is more preferable. A glass that can be produced preferably at 1450 ° C. or lower, more preferably at 1400 ° C. or lower can be provided.

  The glass of the present invention is suitable as various substrate materials, structural members, transmission optical system materials and the like that require thermal dimensional stability and heat resistance.

Hereinafter, embodiments of the present invention will be described in detail.
The average linear expansion coefficient of the glass of the present invention is 25 in the range of 0 ° C. to 300 ° C., which is preferably applicable as various substrate materials, structural members, or transmission optical system materials that require thermal dimensional stability and heat resistance. It is in the range of ˜55 × 10 ⁻⁷ ° C. ⁻¹ .

Each component which comprises the glass of this invention is demonstrated. In addition, each said component is expressed by the mass% of an oxide basis.

Here, the “oxide standard” is contained in the glass on the assumption that oxides, nitrates, etc. used as raw materials of the constituent components of the glass of the present invention are all decomposed and changed into oxides when melted. This is a method of expressing the composition of each component, and the amount of each component contained in the glass is described with the total mass of the generated oxides being 100% by mass.

The glass of the present invention, SiO ₂ component include _Al 2 _{O 3} component and MgO component, SiO ₂ component, the total of 80% of _Al 2 _{O 3} component and MgO component exceeds% by mass on the oxide basis, mass% The Al ₂ O ₃ / MgO ratio expressed by the formula is characterized by exceeding 0.57.

The Al ₂ O ₃ component is a component that forms a glass skeleton together with SiO ₂ in the present invention. Further, the Al ₂ O ₃ component has an effect of improving the heat resistance and suppressing the phase separation of the glass. Then, the _Al 2 _O 3 / MgO, the ratio by to exceed 0.57, while maintaining a low melting temperature, average linear expansion coefficient of 25 to 55 × ^{10 -7} ° C. at 0 to 300 ° C. ^-1 It becomes possible to set it as the glass in the range.

In order to easily obtain a lower average linear expansion coefficient and a lower melting temperature, the Al ₂ O ₃ / MgO ratio is preferably 0.7 or more, and most preferably 1.0 or more. preferable.

If the content of the Al ₂ O ₃ component is less than 8%, phase separation tends to occur and the above effect cannot be obtained sufficiently. Therefore, the lower limit of the content of this component is preferably 8%. In order to sufficiently obtain the above effects, the lower limit of the Al ₂ O ₃ component is more preferably 12%, and most preferably 16%.

Further, if the content of the Al ₂ O ₃ component exceeds 25%, the meltability is remarkably lowered. Therefore, the upper limit of the content of this component is preferably 25%, more preferably 22%, more preferably 20% Is most preferable.

  In the present invention, the MgO component is an important component that has the effect of reducing the viscosity of the glass and suppressing devitrification. Since these effects are not sufficient when the content of the MgO component is less than 10%, the lower limit of the content of this component is preferably 10%, more preferably 12%, and most preferably 14%. preferable.

  On the other hand, when the content of the MgO component exceeds 20%, a desired thermal expansion coefficient cannot be obtained. Therefore, the upper limit of the content of this component is preferably 20%, more preferably 18%, and most preferably 16%.

The SiO ₂ component is a component that can form the skeleton of the glass of the present invention. By containing this component, the glass of the present invention can easily obtain a lower average linear expansion coefficient.

In order to easily obtain a desired average linear expansion coefficient, the lower limit of the content of the SiO ₂ component is preferably 50%, more preferably 52%, and most preferably 53%.

Further, in order to lower the melting temperature of the glass of the present invention and improve the low temperature melting property, the upper limit of the content of SiO ₂ component is preferably 65%, more preferably 62%. 60% is most preferable.

In order to obtain a melting temperature of 1450 ° C. when the viscosity of the glass raw material is 10 ^2.5 dPa · s while obtaining the desired average linear expansion coefficient of the present invention, the SiO ₂ component, Al The total amount of ₂ O ₃ component and MgO component is preferably more than 80%.

The B ₂ O ₃ component has the effect of functioning as a flux when producing a low expansion glass. When the content of the B ₂ O ₃ component is less than 1%, it is difficult to melt the glass raw material. Therefore, the lower limit of the content of the B ₂ O ₃ component is preferably 1%, and 1.5%. More preferably, it is 2%.

Further, if the content of the B ₂ O ₃ component exceeds 10%, the viscosity of the glass melt increases and molding becomes difficult. Therefore, the upper limit of the content of the B ₂ O ₃ component is preferably 10%. 9% is more preferable, and 8% is most preferable.

Each component of _{Li 2 O, Na 2 O,} K 2 O , since the effect of improving the meltability of the glass, can be added as an optional component. However, if the content of each of these components exceeds 10%, it becomes difficult to obtain a desired thermal expansion coefficient. Therefore, the upper limit of the content of each of these components is preferably 10%, preferably 5% More preferably, it is more preferably less than 2%.
In order to easily obtain a desired thermal expansion coefficient, the total content of these components is more preferably 10% or less.

  The CaO component is a component that can be optionally added because it improves the low-temperature meltability and easily suppresses the devitrification tendency. However, as the content increases, the acid resistance tends to decrease and the average linear expansion coefficient tends to increase, so the upper limit of the content is preferably 5%, more preferably less than 4%, and most preferably less than 2%. It is.

  The BaO component is a component that can be optionally added because it makes it easier to improve the low-temperature meltability. However, since the average linear expansion coefficient tends to increase when the addition amount is large, the upper limit of the content is preferably 5%, more preferably less than 4%, and most preferably less than 2%.

The ZrO ₂ component is an ingredient that can be optionally added because it has the effect of improving the chemical durability of the glass. However, since the melting temperature increases when the content exceeds 5%, the upper limit of the content of this component is preferably 5%, more preferably less than 4%, and most preferably less than 3%.

The As ₂ O ₃ component and / or the Sb ₂ O ₃ component are components that can be optionally added as a glass refining agent. However, even if added in a large amount, the clarification effect does not increase, so the upper limit is 1%, preferably less than 0.5%, and most preferably less than 0.3%. Further, these components are problematic components from the viewpoint of environmental protection. Therefore, when the glass contains a defoaming component other than these components, it is preferable to refrain from adding these components.

  Since the PbO component requires measures for environmental measures when manufacturing, processing, and discarding the glass, and costs are required for this, PbO should not be contained in the glass of the present invention.

  Furthermore, in the glass of the present invention, each oxide component such as V, Cr, Mn, Fe, Co, Ni, Mo, Eu, Nd, Sm, Tb, Dy, and Er contributes little to the object of the present invention. Since glass is colored, it is preferably not contained when considering use as a transmission optical system material.

However, the term “not contained” means that it is not contained artificially unless it is mixed as an impurity.
Other components may be added as long as they do not impair the gist of the present invention.

  The low expansion glass of the present invention is also excellent in chemical durability, and may exhibit either first grade or second grade in both powder method water resistance and powder method acid resistance defined by the Japan Optical Glass Industry Association Standard (JOGIS). Proven.

  As a method for producing the glass of the present invention, a known melting method can be used. That is, a glass material made of silica sand, boric acid, aluminum oxide, magnesium oxide, calcium carbonate, barium nitrate, arsenous acid or the like is made of quartz or platinum so that the glass of the present invention has a composition expressed on an oxide basis. Fill crucible. And it heat-melts in melting furnaces, such as an electric furnace and a gas furnace. In many cases, the glass of the present invention has a melting temperature of glass raw material of 1450 ° C. or lower, and the temperature at the time of heating and melting in the melting furnace is 1450 ° C. or lower. Can do.

  After melting, clarification and stirring are performed as necessary to homogenize the glass, and then the molten glass is poured into a mold and rapidly cooled to form and slowly cool in a slow cooling furnace.

  The glass taken out from the slow cooling furnace can be cut, ground, and polished as necessary to obtain various substrate materials, structural members, and transmission optical system materials.

  Examples of the present invention will be described. From silica sand, boric acid, aluminum oxide, magnesium oxide, calcium carbonate, barium nitrate, lithium carbonate, sodium carbonate, potassium carbonate, zirconium oxide and arsenous acid so that the glass has the composition ratio shown in Table 1 expressed on an oxide basis A glass raw material batch was prepared. The batch was filled in a platinum crucible and heated and melted in an electric furnace at 1340 ° C. to 1450 ° C. for 6 hours. The molten glass was molded into a plate shape and slowly cooled.

  The average linear thermal expansion coefficient was measured using a low-temperature dilatometer made by Mac Science, by preparing a sample of φ3 × 25 mm from the glass plate obtained above.

Tables 1 and 2 show the glass composition, melting temperature, and average linear expansion coefficient (α) at 0 to 300 ° C. expressed in terms of mass% based on oxides in the examples of the present invention. The melting temperature is a temperature at which the viscosity is 10 ^2.5 dPa · s. Moreover, the relationship between the viscosity and the temperature at the time of melting in Examples 1, 2, and 7 is shown in FIG.

All the glasses of the above examples have an average linear expansion coefficient in the range of 25 to 55 × 10 ⁻⁷ ° C.− ¹ at 0 ° C. to 300 ° C., and the viscosity of the glass raw material is 10 ^2.5 dPa · s. The melting temperature of is 1450 ° C. or lower.

  These glasses were sequentially processed by cutting, grinding, and polishing to prepare a substrate material, a structural member, and a transmission optical material. All of these have thermal dimensional stability and heat resistance, and can be manufactured at a lower cost than the conventional heat-low expansion glass and ceramic materials, and can be easily processed.

It is a graph which shows the relationship between the viscosity in the case of the melting of the glass raw material of this invention, and temperature.

Claims (7)

It contains SiO ₂ component, Al ₂ O ₃ component and MgO component on oxide basis, and the total of SiO ₂ component, Al ₂ O ₃ component and MgO component exceeds 80% by mass% on oxide basis, Al ₂ O ₃ glass weight ratio _Al 2 _O 3 / MgO component and MgO component exceeds 0.57, and an average linear expansion coefficient at 0 to 300 ° C. is characterized in that it is a 25~55 × ^{10 -7} ℃ ^-1. _2. The glass according to claim 1, comprising 50 to 65% of a SiO ₂ component based on an oxide-based mass%. _{3. The} composition according to claim 1, comprising 8 to 25% of an Al ₂ O ₃ component, 10 to 20% of an MgO component, and 1 to 10% of a B ₂ O ₃ component by mass% based on an oxide. Glass. 0 to 5% of CaO component in weight percent on the oxide basis, and / or BaO ingredients 0-5%, and / or a ZrO ₂ component 0-5%, and / or Li ₂ O component 0-10% 4. The glass according to claim 1, comprising 0 to 10% of a Na ₂ O component and / or 0 to 10% of a K ₂ O component. The glass according to any one of claims 1 to 4, comprising 0 to 1% of an As ₂ O ₃ component and / or an Sb ₂ O ₃ component in terms of mass% based on an oxide. The glass according to any one of claims 1 to 5, wherein the temperature when the viscosity of the glass exhibits 10 ^2.5 dPa · s is 1450 ° C or lower.   The glass according to any one of claims 1 to 6, wherein the glass exhibits a first grade or a second grade in the powder method water resistance and the powder method acid resistance defined by the Japan Optical Glass Industry Association Standard (JOGIS).

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