JP2010064922A - Glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide low thermal expansive glass exhibiting a superior clarifying effect and high productivity at the same time without containing an As ingredient and an Sb ingredient. <P>SOLUTION: The glass is characterized by including an SiO<SB>2</SB>ingredient, an Al<SB>2</SB>O<SB>3</SB>ingredient, a B<SB>2</SB>O<SB>3</SB>ingredient and a CeO<SB>2</SB>ingredient and/or an SnO<SB>2</SB>ingredient in terms of oxides and by that the total amount γ of the CeO<SB>2</SB>ingredient and/or the SnO<SB>2</SB>ingredient is satisfied with an equation of γ≥0.005α+0.0189β<SP>2</SP>+0.011β-5.5 (wherein, α is liquid phase temperature; and β is the content of the B<SB>2</SB>O<SB>3</SB>ingredient). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a low thermal expansion glass with a reduced content of harmful substances.

Low thermal expansion glass having a low average linear expansion coefficient is used in a wide range of fields such as substrate materials and heat-resistant glass in the precision instrument field. Since such glass generally has a relatively large amount of SiO ₂ component, the viscosity of the glass in the liquid phase in the production process is high, and clarification is difficult. Therefore, such a low thermal expansion glass has obtained a clarification effect by containing an As component and an Sb component. The As component or Sb component has a high refining effect, so it has been indispensable for the production of low thermal expansion glass with high viscosity of molten glass and difficult to escape bubbles. Accordingly, there is a demand for low thermal expansion glass that does not contain As and Sb components.

Low thermal expansion glass has a high viscosity of molten glass and a high liquidus temperature. By containing B ₂ O ₃ component, the viscosity of molten glass is made as low as possible and the liquidus temperature is lowered to improve the moldability. Or reducing the operating temperature of the melting furnace to ensure productivity. The B ₂ O ₃ component has the effect of lowering the viscosity of the molten glass while suppressing an increase in the average thermal expansion coefficient, so that the bubbles are likely to rise and the clarification is easy, while the B ₂ O ₃ component itself is Because of its high volatility, it tends to cause reboiling (re-foaming) during glass melting. Therefore, when using a defoaming agent having a high clarification effect such as an As component or Sb component, sufficient clarification is realized by the effect of reducing the viscosity of the molten glass while suppressing reboiling by the B ₂ O ₃ component. However, under the situation where the use of As and Sb components is restricted, the reboiling caused by the B ₂ O ₃ component cannot be suppressed, making glass clarification more difficult. Development of expandable glass is extremely difficult.

The glass described in Patent Document 1 discloses a low thermal expansion glass having a thermal expansion coefficient of 38 × 10 ⁻⁷ ° C. ^{−1 to} 52 × 10 ⁻⁷ ° C. ⁻¹ with no use of As and Sb components. The number of bubbles per gram of the glass after melting and slow cooling is large, and the clarification effect is not sufficient when considering applications in the field of precision instruments.
JP 2004-284949 A

  An object of the present invention is to provide a low thermal expansion glass that achieves both a good fining effect and high productivity without containing an As component and an Sb component.

As a result of intensive studies in view of the above problems, the present inventor has made SiO ₂ component, Al ₂ O ₃ component and B ₂ O ₃ component as main components, and CeO ₂ component and / or SnO ₂ component as clarifying agents. When these contents, the liquidus temperature of the glass, and the content of the B ₂ O ₃ component satisfy a specific relationship, it is possible to obtain a glass having both good clarity and high productivity. As a result, the present invention has been completed, and its specific configuration is as follows.

(Configuration 1)
Containing SiO ₂ component, Al ₂ O ₃ component, B ₂ O ₃ component, CeO ₂ and / or SnO ₂ component on oxide basis,
The total amount γ of CeO ₂ component and / or SnO ₂ component satisfies the relationship of γ ≧ 0.005α + 0.0189β ² + 0.011β-5.5 (α: liquidus temperature β; content of B ₂ O ₃ component) A glass characterized by that.
(Configuration 2)
48 to 65% of SiO ₂ component by mass% based on oxide
Al ₂ O ₃ component 8-25%
B ₂ O ₃ component exceeds 0%, glass according to the structure 1 containing 12% or less.
(Configuration 3)
The glass according to Configuration 1 or 2, wherein the glass contains 0.01 to 3% of a CeO ₂ component and / or a SnO ₂ component by mass% based on an oxide.
(Configuration 4)
0 to 5% CaO component and / or 0 to 20% MgO component and / or 0 to 5% BaO component and / or 0 to 5% SrO component and / or Or 0-15% of ZnO component, and / or 0-5% of ZrO ₂ component, and / or 0-5% of TiO ₂ component, and / or Li ₂ O component, Na ₂ O component, K ₂ O component The glass according to any one of the structures 1 to 3, which contains 0 to 10% of a total of one or more components selected from the group consisting of:
(Configuration 5)
One or more of each component of Y ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O ₃ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O ₅ in mass% based on the oxide Glass in any one of the structures 1-4 characterized by containing a total in 0 to 7% of range.
(Configuration 6)
The glass according to any one of Structures 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 Structures 1 to 6, wherein an average linear expansion coefficient at 0 to 300 ° C. is 25 to 55 × 10 ⁻⁷ ° C. ⁻¹ .
(Configuration 8)
The glass according to any one of Structures 1 to 7, which does not contain F, Cl, Br, I, Pb, As, and Sb elements as glass components.

The glass of the present invention has an average coefficient of linear expansion at 0 to 300 ° C. in the range of 25 to 55 × 10 ⁻⁷ ° C. ⁻¹ , and has a high defoaming property with 50 or less bubbles per 100 cm ^{3 of the} glass after molding. Since the temperature when the viscosity of the glass exhibits 10 ^2.5 dPa · s is 1450 ° C. or lower, melt molding is possible at a low temperature, and the productivity is high.

  Each composition component which comprises the glass of this invention is described. In addition, content of each component is shown by the mass% of an oxide basis. Here, the “oxide standard” is contained in the glass on the assumption that oxides, nitrates and the like 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 contains SiO ₂ component, Al ₂ O ₃ component, B ₂ O ₃ component, CeO ₂ and / or SnO ₂ component on the oxide basis,
The total amount γ of the CeO ₂ component and / or the SnO ₂ component is
It satisfies the relationship of γ ≧ 0.005α + 0.0189β ² + 0.011β−5.5 (α: liquidus temperature β; content of B ₂ O ₃ component).
The SiO ₂ component, Al ₂ O ₃ component, and B ₂ O ₃ component are main components of the low thermal expansion glass, and the CeO ₂ component and / or the SnO ₂ component provide an effect as a fining agent.
Then, the liquidus temperature of the glass determined by the SiO ₂ component, the Al ₂ O ₃ component, the B ₂ O ₃ component and any components contained as necessary, the content of the B ₂ O ₃ component, the CeO ₂ and / or Or, by adding a defoaming agent so that the relationship of the total amount of SnO ₂ components satisfies the above relational expression, reboiling by B ₂ O ₃ components is suppressed, and both good defoaming properties and high productivity are achieved. It becomes possible to do.

Here, the liquidus temperature is a temperature at which precipitation of crystals begins in the process of lowering the temperature of the glass melt in which no crystals exist. The measurement is performed by, for example, using a high-temperature observation stage MS-TPS for microscopes manufactured by Yonekura Seisakusho Co., Ltd., by observing with a microscope while lowering the temperature of the glass melt, and reading the temperature when the precipitation of crystals is confirmed. Just do it.

If the total amount of CeO ₂ and / or SnO ₂ component is contained in the glass than the total amount of CeO ₂ and / or SnO ₂ component satisfies the above relationship is small, defoaming property of the glass is not sufficiently good It is difficult to obtain a low thermal expansion glass that achieves both excellent defoaming properties and high productivity.

Here, the Ce component and the Sn component in the glass of the present invention can take a plurality of valences, but when converted on the basis of the above oxide, they are converted as CeO ₂ and SnO _2, respectively, for example, Ce ₂ O ₃ or Not converted as SnO ₂ or the like.

The SiO ₂ component is a glass network forming component and contributes to low thermal expansion.
In order to easily obtain a desired average linear expansion coefficient, the lower limit of the content of the SiO ₂ component is preferably 48%, more preferably 49%, and most preferably 50%.
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.

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. 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 9%, and most preferably 9.5%.
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 24%, 23% Is most preferable.

Since the B ₂ O ₃ component has an effect of lowering the viscosity and liquid phase temperature of the molten glass, it is preferable to contain more than 0%. When the B ₂ O ₃ component is not contained, the viscosity of the molten glass is increased, the glass moldability is deteriorated, and the melting temperature is increased, so that the productivity of the glass is easily lowered. In order to improve the productivity of the glass, the lower limit of the content of the B ₂ O ₃ component is more preferably 1%, and most preferably 1.5%.
Further, B ₂ O ₃ content of component exceeds 12%, the chemical durability deterioration of the glass resulting in accelerated. Furthermore, since reboiling is likely to occur in the melting step, the upper limit of the content of the B ₂ O ₃ component is preferably 12%, more preferably 11.5%, and most preferably 11%. preferable.

In order to make it easy to obtain a sufficient effect as a defoaming agent, the total amount of at least one CeO ₂ component or SnO ₂ component is preferably 0.01% or more, and more preferably 0.05% or more. More preferably, it is most preferably 0.1% or more.
On the other hand, if the total amount of one or more of the CeO ₂ component or the SnO ₂ component exceeds 3%, Sn is likely to precipitate as a metal, or the visible light short wavelength region and the transmittance in the ultraviolet region are reduced by CeO _2. Is preferably 3% or less, more preferably 2.8% or less, and most preferably 2.5% or less.
The gamma, alpha, satisfy the relationship of beta, and that the high fining effect of the CeO ₂ component or SnO ₂ component above range is more easily obtained. Incidentally, CeO ₂ component or SnO ₂ component is not possible to slow down the clarifying effect be incorporated into both, the effect to be promoted, rather.

In the present invention, the MgO component is a component that can be optionally added because it has the effect of reducing the viscosity of the glass and suppressing devitrification. However, in order to make it easy to obtain the above effect, the lower limit of the content of the MgO component is preferably 10%, and the lower limit of the content is most preferably 12%.
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 19%, and most preferably 18%.

  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 4%, and most preferably 3%. 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 amount added is large, the upper limit of the content is preferably 5%, more preferably 4%, and most preferably 3%.

  The SrO 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 amount added is large, the upper limit of the content is preferably 5%, more preferably 4%, and most preferably 3%.

  The ZnO component is a component that can be optionally added because it facilitates improving the low-temperature meltability. However, since the average linear expansion coefficient tends to increase when the amount added is large, the upper limit of the content is preferably 15%, more preferably 14%, and most preferably less than 13%.

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 4%, and most preferably 3.5%. .

Since the TiO ₂ component has an effect of improving the chemical durability of the glass, it can be optionally added. 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 4%, and most preferably 3%.

Since the Li ₂ O component, the Na ₂ O component, and the K ₂ O component have an effect of improving the meltability of the glass, they can be added as optional components. However, if the content of one or more components selected from the Li ₂ O component, the Na ₂ O component, and the K ₂ O component exceeds 10%, it becomes difficult to obtain a desired thermal expansion coefficient. The upper limit of the component content is preferably 10%, more preferably 8%, and most preferably 6%.

By including one or more components selected from the above Li ₂ O component, Na ₂ O component, and K ₂ O component, the electrical conductivity of the molten glass is increased, and the direct flow by energizing the molten glass directly Resistance heating becomes possible. By manufacturing by direct resistance heating, the use of burners can be reduced as much as possible, the mixing of OH groups into the molten glass due to burner combustion is reduced, and the chemical and physical durability of the glass due to the mixing of OH groups It becomes easy to deter sexual deterioration.

Each component of Y ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O ₃ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O ₅ has the effect of improving the meltability and lowering the liquidus temperature. Therefore, it is a component that can be optionally contained. However, if the content exceeds 7%, the average linear expansion coefficient increases, so the upper limit of the total content of one or more of these components is preferably 7%, more preferably 6.8%. And most preferably 6.5%.

  Since F, Cl, Br, I, Pb, As, and Sb elements are environmentally harmful components, they are preferably not contained as glass constituents.

According to the present invention, the temperature when the viscosity of the glass exhibits 10 ^2.5 dPa · s is 1450 ° C. or less, and according to a more preferred embodiment, the temperature is 1440 ° C. or less, and according to the most preferred embodiment. In this case, the temperature is 1430 ° C. or lower. Therefore, since the temperature of the melting furnace at the time of glass manufacture can be lowered | hung, the cost reduction of the energy required for production and production equipment is realizable.

The average linear expansion coefficient of the glass is at 0 to 300 ° C. of the present invention is in the range of 25~55 × ^{10 -7} ℃ ^-1, the upper limit according to a more preferred embodiment be a 54 × ^{10 -7} ℃ ^-1 According to the most preferable embodiment, 53 × 10 ⁻⁷ ° C.− ¹ or less can be realized.

  Hereinafter, the glass according to the present invention will be described with specific examples.

The glasses of the above examples and comparative examples of the present invention all have the compositions shown in Tables 1 to 3, and oxides, carbonates, nitrates, etc., so that the glass weight is 2,000 (g). The raw materials were mixed. This was melt | dissolved for 24 to 72 hours at the temperature of about 1300-1550 degreeC using the normal melt | dissolution apparatus, it stirred and homogenized, and after shape | molding in the lump shape, the glass molded object was obtained by carrying out distortion removal.
Thereafter, the glass was mirror-finished into a shape of 10 × 10 × 1 (cm), and the number of bubbles was examined by observing the inside with a microscope. The minimum detectable bubble diameter was 10 μm. The average linear expansion coefficient at 0 ° C. to 300 ° C. for a glass of the resulting each (alpha), the liquidus temperature, the temperature was measured (T) at which the viscosity of the glass is ¹⁰ 2.5 dPa · s. These values are listed in the table along with the number of bubbles.

The average linear expansion coefficient was measured by changing the temperature range from 0 ° C. to 300 ° C. according to JOGIS (Japan Optical Glass Industry Association Standard) 16-2003 “Measuring method of average linear expansion coefficient of optical glass near normal temperature”. Value.
The temperature at which the viscosity of the glass is 10 ^2.5 dPa · s is a value measured using BVM-13LH manufactured by Opto Corporation.

As shown in Tables 1 to 7, in the examples of the glass of the present invention, the average coefficient of thermal expansion at an average thermal expansion coefficient of 0 ° C. to 300 ° C. is 35.2 to 52.3 (× 10 ⁻⁷ ° C. ⁻¹ ). Range. In addition, the examples of the present invention satisfy the above relational expression of γ, α, β, the number of remaining bubbles contained in 100 cm ^{3 of} glass is 12 to 45, and a large amount of antimony component and arsenic component are used. The results showed clear characteristics comparable to those of the results.

(Comparative example)
On the other hand, in Comparative Examples 1 to 3, when the number of remaining bubbles contained in 100 cm ^{3 of} glass was observed, the number of remaining bubbles was 130 to 210. For example, since the boric acid content in Comparative Example 1 is 6.8% and the liquidus temperature is 1160 ° C., α = 1160 and β = 6.8 in the above 0.005α + 0.0189β ² + 0.011β−5.5. As a result of substituting the value, γ ≧ 1.249. At this time, since the CeO ₂ content corresponding to γ of Comparative Example 1 is 0.1, it is understood that the relational expression is not satisfied and a sufficient defoaming effect cannot be obtained.

Claims (8)

Containing SiO ₂ component, Al ₂ O ₃ component, B ₂ O ₃ component, CeO ₂ and / or SnO ₂ component on oxide basis,
The total amount γ of CeO ₂ component and / or SnO ₂ component satisfies the relationship of γ ≧ 0.005α + 0.0189β ² + 0.011β-5.5 (α: liquidus temperature β; content of B ₂ O ₃ component) A glass characterized by that. 48 to 65% of SiO ₂ component by mass% based on oxide
Al ₂ O ₃ component 8-25%
Glass according to claim 1, wherein the B ₂ O ₃ component exceeds 0%, containing 12% or less. 3. The glass according to claim 1, wherein the glass contains 0.01 to 3% of a CeO ₂ component and / or a SnO ₂ component by mass% based on an oxide. 0 to 5% CaO component and / or 0 to 20% MgO component and / or 0 to 5% BaO component and / or 0 to 5% SrO component and / or Or 0-15% of ZnO component, and / or 0-5% of ZrO ₂ component, and / or 0-5% of TiO ₂ component, and / or Li ₂ O component, Na ₂ O component, K ₂ O component The glass according to any one of claims 1 to 3, comprising 0 to 10% of a total of one or more components selected from the group consisting of: One or more of each component of Y ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O ₃ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O ₅ in mass% based on the oxide The glass according to any one of claims 1 to 4, comprising a total content of 0 to 7%. 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 average linear expansion coefficient in 0-300 degreeC is 25-55 * 10 < ^-7 > degreeC- ¹ , The glass in any one of Claims 1-6 characterized by the above-mentioned.   The glass according to any one of claims 1 to 7, wherein F, Cl, Br, I, Pb, As, and Sb elements are not contained as glass constituents.