WO2017110799A1 - Glass having fine bubbles and method for manufacturing same - Google Patents

Glass having fine bubbles and method for manufacturing same Download PDF

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Publication number
WO2017110799A1
WO2017110799A1 PCT/JP2016/087925 JP2016087925W WO2017110799A1 WO 2017110799 A1 WO2017110799 A1 WO 2017110799A1 JP 2016087925 W JP2016087925 W JP 2016087925W WO 2017110799 A1 WO2017110799 A1 WO 2017110799A1
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Prior art keywords
glass
bubbles
less
cross
bubble diameter
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PCT/JP2016/087925
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French (fr)
Japanese (ja)
Inventor
長嶋　達雄
学 西沢
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旭硝子株式会社
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Priority to JP2017558150A priority Critical patent/JPWO2017110799A1/en
Publication of WO2017110799A1 publication Critical patent/WO2017110799A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • 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
    • C03C11/00—Multi-cellular glass ; Porous or hollow glass or glass particles
    • 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
    • C03C3/12—Silica-free oxide glass compositions
    • C03C3/16—Silica-free oxide glass compositions containing phosphorus
    • C03C3/17—Silica-free oxide glass compositions containing phosphorus containing aluminium or beryllium

Definitions

  • the present invention relates to glass containing minute bubbles and a method for producing the same.
  • Bubbles (bubbles) in the glass are usually recognized as defects. Therefore, usually glass without bubbles is desired.
  • a glass such as porous glass and foamed glass in which pores and bubbles are present in the glass and a method for producing the same have also been proposed.
  • Patent Document 1 describes that porous glass having pores in glass can be obtained by subjecting borosilicate glass to phase separation and then acid treatment.
  • Patent Document 2 describes that after a foaming agent such as SiC is mixed into finely pulverized glass, they are molded and fired to obtain foamed glass.
  • the porous glass described in Patent Document 1 since the pores in the porous glass described in Patent Document 1 have a large aspect ratio, the porous glass has anisotropy. Therefore, when the porous glass is viewed from the outside, the pores are observed with the naked eye depending on the viewing direction. Moreover, since acid treatment is required to produce the porous glass, when a phase that elutes into the acid in the phase-separated glass elutes, it is necessary to use a large amount of acid and waste liquid treatment, It takes a long time to elute the phase that elutes in the acid, and there is a problem in terms of productivity.
  • the aspect ratio of the bubbles in the obtained foamed glass is approximately 1, but in the method for producing the foamed glass, it is difficult to control the bubble diameter and the bubble distribution. It is difficult to obtain a glass with good appearance that is not visually recognized.
  • an object of the present invention is to provide a glass having a good appearance from an arbitrary direction while containing bubbles, and a method for producing the same.
  • glass having good appearance means a glass in which bubbles are not visually recognized when observed with the naked eye from the outside.
  • the present invention is a glass containing bubbles, and when the cross section of the glass is observed, the number of the bubbles in the cross section is 1.0 ⁇ 10 2 pieces / mm 2 or more, and Provided is a glass having a bubble diameter of 50 ⁇ m or less and an aspect ratio of 1.25 or less.
  • the present invention also includes a melting step of melting glass while being pressurized to 0.2 to 100 MPa, a cooling step of cooling the melted glass, and a slow cooling step of slowly cooling the cooled glass A manufacturing method is also provided.
  • Bubbles having a bubble diameter of 50 ⁇ m or less and an aspect ratio of 1.25 or less, which are contained in the glass of the present invention, are minute bubbles that are not visible by observation with the naked eye from an arbitrary direction. Therefore, the glass of the present invention having the above-described configuration has good appearance, since bubbles are not visually recognized from any direction while containing bubbles.
  • the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of the bubbles. It can develop properties.
  • an optical element such as an optical element, an electrical element, a thermoelectric conversion element, an acoustic element, and a lightweight heat insulating material
  • the optical element include a wavelength selection filter, a light emitting element, and a solar battery
  • specific examples of the electric element include an insulator, a capacitor, and a secondary battery.
  • the glass of the present invention can be efficiently manufactured without requiring a complicated process.
  • FIG. 1 is a cross-sectional SEM image of glass according to Example 1 (Example).
  • FIG. 2 is a cross-sectional SEM image of the glass according to Example 2 (Example).
  • the glass of the present invention is a glass containing bubbles, and when the cross section of the glass is observed, the number of the bubbles in the cross section is 1.0 ⁇ 10 2 pieces / mm 2 or more, and The bubble diameter is 50 ⁇ m or less, and the aspect ratio is 1.25 or less.
  • bubbles having a bubble diameter of 50 ⁇ m or less and an aspect ratio of 1.25 or less may be referred to as “fine bubbles”.
  • the bubble diameter of the bubble in the present invention represents a bubble diameter read from an SEM image obtained by observing a cross section of the glass with a scanning electron microscope (SEM).
  • the aspect ratio of the bubble in the present invention is calculated as a major axis / minor axis by reading the major axis and minor axis of a bubble from an SEM image obtained by observing a cross section of the glass with a scanning electron microscope (SEM). Represents the value to be
  • Bubbles having a bubble diameter of 50 ⁇ m or less and an aspect ratio of 1.25 or less are not visually recognized when the glass is observed with the naked eye from an arbitrary direction.
  • the number of fine bubbles in the cross section is 1.0 ⁇ 10 2 / mm 2 or more, and the appearance from any direction is contained while containing bubbles. Is good.
  • bubble diameter, bubble aspect ratio, and number of bubbles are the pressure conditions during melting of the glass, melting temperature, blowing agent, atmosphere, and cooling rate during cooling when manufacturing the glass of the present invention. It can be adjusted by appropriately adjusting each condition such as a slow cooling condition.
  • the fine bubble has a bubble diameter of 50 ⁇ m or less, preferably 20 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 500 nm. Or less, particularly preferably 200 nm or less.
  • the lower limit of the bubble diameter of the fine bubble is not particularly limited, but is 1 nm or more, for example, from the viewpoint of various characteristics and bubble density.
  • the fine bubble has an aspect ratio of 1.25 or less, preferably 1.2 or less, more preferably 1.15, from the viewpoint of obtaining good appearance from any direction. Or less, more preferably 1.1 or less, or the fine bubble may be a perfect circle (aspect ratio is 1).
  • the number of fine bubbles in the cross section (hereinafter also referred to as bubble density) is 1.0 ⁇ 10 2 pieces / mm 2 or more, preferably 1.0 ⁇ 10 3 pieces / mm 2 or more, more preferably 5.0 ⁇ 10 5 pieces / mm 2 or more.
  • the upper limit of the said foam density is not specifically limited, From a viewpoint on manufacture, it is 1.0 * 10 ⁇ 12 > pieces / mm ⁇ 2 > or less, for example.
  • the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of fine bubbles. It can develop properties.
  • the number of bubbles in the cross section when the cross section of the glass is observed is 5.0 ⁇ 10 4 pieces / mm 2 or more, and the bubbles of the bubbles Glass having a diameter of 500 nm or less has a low mean thermal process, so that the glass has low thermal conductivity and high heat insulating properties.
  • the bubble diameter is 200 nm or less and the bubble density is 5.0 ⁇ 10 5 pieces / mm 2 or more, the bubble diameter is 100 nm or less and the bubble density is 1.0 ⁇ 10 6 pieces. / Mm 2 or more is more preferable.
  • the aspect ratio of the bubbles is within the above-described range.
  • the number of bubbles in the cross section when the cross section of the glass is observed is 2.0 ⁇ 10 2 pieces / mm 2 or more, and Glass having a bubble diameter of 20 ⁇ m or less has a high porosity, and thus has a low specific gravity and is lightweight.
  • the bubble diameter is 1 ⁇ m or less and the number of bubbles is 5.0 ⁇ 10 4 / mm 2 or more, the bubble diameter is 500 nm or less, and the bubble density is 2.0 ⁇ 10 5. It is more preferable that the number of particles / mm 2 or more.
  • it is desirable that the bubble diameter is small and the bubble density is large.
  • the bubble diameter works as a third power against the porosity, more bubbles are introduced as the bubble diameter becomes smaller. This is inefficient in terms of manufacturing.
  • the bubble diameter is 20 nm or more and the bubble density is 2.0 ⁇ 10 9 cells / mm 2 or less. In this aspect, the aspect ratio of the bubbles is within the above-described range.
  • the number of the bubbles in the cross section when the cross section of the glass is observed is 1.0 ⁇ 10 2 pieces / mm 2 or more, and Glass having a bubble diameter of 15 ⁇ m or less and an aspect ratio of 1.2 or less can increase scattering efficiency at a predetermined wavelength from ultraviolet light to infrared light depending on the bubble diameter. It is suitable as an optical element.
  • the bubble diameter is 10 ⁇ m or less
  • the aspect ratio is 1.1 or less
  • the bubble density is 2.0 ⁇ 10 2 pieces / mm 2 or more.
  • the bubble diameter is in the range of 100 to 550 nm and the bubble density is in the range of 2.0 ⁇ 10 4 to 1.0 ⁇ 10 6 pieces / mm 2 . You can choose from.
  • the bubble diameter is 7 ⁇ m or less and the bubble density is 2.0 ⁇ 10 2 pieces / mm 2 or more. It is preferable that
  • the glass of the present invention preferably contains no bubbles other than bubbles having a bubble diameter of 50 ⁇ m or less and an aspect ratio of 1.25 or less.
  • the bubbles may be visually recognized. As a result, the appearance of the glass may be deteriorated.
  • the kind of glass used for the glass of the present invention is not particularly limited, and can be appropriately selected and applied from various known glasses. Examples thereof include soda lime glass, aluminosilicate glass, borosilicate glass, phosphate glass, fluorophosphate glass, halide glass, and chalcogenite glass.
  • the shape of the glass of the present invention is not particularly limited, and can take various shapes such as a plate shape, a block shape, a tubular shape, and a fiber shape according to the application to be applied.
  • the glass of the present invention may be appropriately subjected to tempering treatment such as chemical tempering treatment and physical tempering treatment.
  • tempering treatment such as chemical tempering treatment and physical tempering treatment.
  • a publicly known method can be employed without particular limitation as the strengthening processing method.
  • the tempered glass subjected to the tempering treatment can be used for a light and highly insulated window glass, an automobile window glass and the like.
  • the glass production method of the present invention includes a melting step for melting glass while being pressurized to 0.2 to 100 MPa, a cooling step for cooling the melted glass, and a slow cooling step for gradually cooling the cooled glass. Is provided.
  • the glass manufacturing method of the present invention can be easily manufactured.
  • the present inventors are able to crush bubbles (especially fine bubbles) with a small bubble diameter generated in the molten glass by melting the glass while applying pressure at a predetermined pressure.
  • fine bubbles having a predetermined number of bubbles and a predetermined bubble diameter and a predetermined aspect ratio can be maintained and contained in the molten glass.
  • the glass production method of the present invention In the glass production method of the present invention, first, the glass is melted while being pressurized to 0.2 to 100 MPa. When the pressure during the melting step is 0.2 MPa or more, fine bubbles can be efficiently contained in the glass melt.
  • the pressure is preferably 0.3 MPa or more, and more preferably 0.5 MPa or more. On the other hand, if the pressure during the melting step is greater than 100 MPa, the pressure-resistant container at the time of production is limited, and the cost may be enormous.
  • the pressure is preferably 50 MPa or less, and more preferably 10 MPa or less.
  • the glass raw material is sealed in an appropriate container such as a quartz tube. At this time, it may be sealed while evacuating.
  • the pressure when evacuating at the time of sealing is, for example, 10 to 30 Pa.
  • the container enclosing the glass raw material is held for a predetermined time while being heated to a temperature higher than the melting temperature of the encapsulated glass raw material.
  • the holding time is, for example, 2 to 48 hours.
  • a glass raw material will be melt
  • fine bubbles are included in the melted glass.
  • the glass is melted by a general melting method in advance and cooled to prepare a cullet, and then the cullet is placed in a pressure vessel, and the temperature is raised and the glass reaches a melt, and then a desired gas is introduced and added. You may make it press.
  • a foaming agent having a desired high vapor pressure may be added.
  • Desired gases and foaming agents are, for example, soda lime glass, aluminosilicate glass, borosilicate glass, phosphate glass, etc., in the case of gas, oxygen, carbon dioxide, sulfuric acid gas, etc. Examples include salts, fluorides, and chlorides.
  • a foaming agent it is preferable to add in the range of 0.1 to 10% by mass with the total mass of glass being 100% by mass. More preferably, the content is 0.2 to 5% by mass, and still more preferably 0.5 to 3% by mass.
  • the melting temperature is not particularly limited, but is preferably in the range of 600 to 1700 ° C.
  • the upper limit temperature of the melting temperature is preferably not more than the heat resistant temperature of the container.
  • a quartz tube is used for the container, it is preferably 1000 ° C. or lower. More preferably, it is 950 degrees C or less, More preferably, it is 900 degrees C or less.
  • the melting temperature is preferably equal to or higher than the devitrification temperature of the glass.
  • a cooling step for cooling the melted glass containing fine bubbles is performed. Thereby, the melted glass is cooled and solidified in a state of enclosing the fine bubbles, and the fine bubbles are held inside the glass.
  • a known method can be appropriately adopted.
  • the cooling rate in the cooling step is not particularly limited, but the cooling rate is 100 ° C./min or more in order to cool and solidify the glass while maintaining the state in which the molten glass contains fine bubbles. It is preferably 300 ° C./min or more.
  • the upper limit of the cooling rate is not particularly limited, it is preferably 6000 ° C./min or less, more preferably 1000 ° C./min or less from the viewpoint of reducing the load on the melting equipment and the pressure vessel. .
  • a slow cooling step of slow cooling the glass is performed to remove the distortion of the glass.
  • the cooling rate in the slow cooling step is not particularly limited, but is preferably 100 ° C./min or less, more preferably 10 ° C./min or less, from the viewpoint of removing residual strain of glass and preventing breakage. It is.
  • the glass manufacturing method of the present invention may further include other steps in addition to the melting step, the cooling step, and the slow cooling step.
  • a forming step for forming the glass into a desired shape and a glass refining step may be appropriately provided.
  • a well-known method is employable suitably as a shaping
  • Examples 1 to 3 and 6 are Examples, Examples 4 and 7 are Comparative Examples, and Example 5 is a Reference Example.
  • Example 1 Glass raw materials were mixed so as to have a composition of Ge 4%, Sb 10%, and S 86% (hereinafter also referred to as glass composition 1) in terms of atomic% to obtain a 10 g raw material batch. Further, one end of a quartz tube having an inner diameter of 8 mm was heated and sealed with an oxyhydrogen burner to produce a quartz glass ampule, which was then washed with isopropyl alcohol (IPA) and dried at 600 ° C. under reduced pressure. Subsequently, the raw material batch was placed in a quartz glass ampule and pressed, and then the opening was heated with an oxyhydrogen burner while evacuating at 10 to 30 Pa to seal the quartz glass ampule.
  • IPA isopropyl alcohol
  • the quartz glass ampule in which the raw material batch is sealed is placed in a melting furnace that has been heated to 200 ° C. in advance, and the glass raw material is melted by raising the temperature to 800 ° C. at a temperature rising rate of 2 ° C./min. Retained.
  • the internal pressure in the quartz tube estimated from the vapor pressure curve of sulfur was about 8 MPa.
  • the sealed quartz glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified.
  • the cooling rate was about 3000 ° C./min.
  • the sealed quartz glass ampule was placed in an electric furnace heated to 230 ° C., and slowly cooled to room temperature at a temperature lowering rate of ⁇ 0.5 ° C./min to produce the glass of Example 1.
  • the glass taken out from the sealed quartz glass ampule was cut and polished to prepare three plate-like glass samples having a thickness of about 1 mm. Further, the glass transition point Tg of the glass powder obtained by pulverizing a part of the glass after taking out the three plate-like glass samples is measured with a differential thermal analyzer (trade name: TG8110, manufactured by Rigaku Corporation). It was 225 degreeC when measured using.
  • Example 2 In Example 2, a quartz glass ampoule in which a raw material batch of glass raw materials is enclosed is placed in a melting furnace that has been heated to 200 ° C. in advance, and the temperature is raised to 700 ° C. at a rate of 2 ° C./min.
  • the glass of Example 2 was produced in the same manner as in Example 1 except that the glass raw material was dissolved and held for 2 hours.
  • the internal pressure in the quartz tube inferred from the vapor pressure curve of sulfur was about 3 MPa.
  • three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 2 in the same manner as in Example 1.
  • the glass transition point Tg of the glass of Example 2 was measured in the same manner as in Example 1, it was 224 ° C.
  • glass composition 2 In terms of atomic%, P 14.3%, Mg 0.5%, Ca 0.5%, Sr 2.8%, Ba 8.2%, Li 16%, Al 7.2%, Y 0.5% 600 g of glass raw material was mixed so that the composition of O 32.8% and F 17.2% (hereinafter also referred to as glass composition 2) was obtained. After putting this in a platinum crucible, the glass raw material was melted by heating to 900 ° C. with an electric furnace, and the melt was quenched with a rotating roll to form a glass ribbon. The obtained glass ribbon was pulverized with a ball mill and passed through a sieve having a mesh with an opening of 150 ⁇ m to obtain glass powder. In addition, the glass transition point Tg of this glass powder was 372 degreeC.
  • the sealed glass glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified.
  • the cooling rate was about 3000 ° C./min.
  • the sealed quartz glass ampule was placed in an electric furnace heated to 400 ° C., and slowly cooled to room temperature at a temperature decrease rate of ⁇ 1 ° C./min to produce the glass of Example 3.
  • three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 3 in the same manner as in Example 1.
  • Example 4 200 g of the glass powder obtained in the same manner as in Example 3 was weighed and placed in a platinum crucible, and 2 g of BaF 2 was further added, and then the temperature was raised to 900 ° C. in an electric furnace to dissolve the glass powder and held for 30 minutes. . Next, after stirring for 10 minutes using a platinum stirrer at a rotational speed of 500 rpm, the platinum crucible is placed in an electric furnace heated to 400 ° C. and gradually cooled to room temperature at a temperature reduction rate of ⁇ 1 ° C./min. Cooled to produce the glass of Example 4. In addition, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 4 in the same manner as in Example 1.
  • Example 5 In the same manner as in Example 3, 300 g of a glass raw material was mixed and placed in a platinum crucible, and then heated to 900 ° C. in an electric furnace to dissolve the glass raw material and clarify for 1 hour. Next, the platinum crucible was placed in an electric furnace heated to 400 ° C. and slowly cooled to room temperature at a temperature decrease rate of ⁇ 1 ° C./min to produce the glass of Example 5. Further, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 5 in the same manner as in Example 1.
  • Example 6 10 g of the glass powder obtained in the same manner as in Example 3 was weighed, 0.1 g of BaF 2 and 0.25 g of Eu 2 O 3 were added, and the quartz glass ampoule similar to that in Example 1 was not evacuated. The glass powder was melted by sealing and heated to 800 ° C. at a rate of 2 ° C./min, and held for 1 hour. Here, the internal pressure in the quartz tube inferred from the critical pressure of F was about 5 MPa. Next, the sealed glass glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified. The cooling rate was about 3000 ° C./min.
  • Example 6 the sealed quartz glass ampule was placed in an electric furnace heated to 400 ° C., and slowly cooled to room temperature at a temperature decrease rate of ⁇ 1 ° C./min to produce the glass of Example 6. Also, four plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 6 in the same manner as in Example 1.
  • Example 7 200 g of the glass powder obtained in the same manner as in Example 3 was weighed and placed in a platinum crucible, 2 g of BaF 2 and 5 g of Eu 2 O 3 were further added, and the temperature was raised to 800 ° C. in an electric furnace to obtain the glass powder. Dissolve and hold for 30 minutes. Next, after stirring for 10 minutes using a platinum stirrer at a rotational speed of 500 rpm, the platinum crucible is placed in an electric furnace heated to 400 ° C. and gradually cooled to room temperature at a temperature reduction rate of ⁇ 1 ° C./min. It cooled and produced the glass of Example 7. Also, four plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 7 in the same manner as in Example 1.
  • the aspect ratio was obtained by reading the major axis and minor axis of the bubbles from the SEM image and calculating the major axis / minor axis. The results are shown in Tables 1 and 2. Further, Tables 1 and 2 show whether or not bubbles are visually recognized when the glass is observed with the naked eye from an arbitrary direction.
  • FIG. 1 shows one of the SEM images of the surface of the plate-like glass sample obtained from the glass of Example 1.
  • FIG. 2 shows one of the SEM images of the surface of the plate-like glass sample obtained from the glass of Example 2.
  • the glass melt was pressurized by the increase in vapor pressure accompanying the temperature increase in the quartz sealed tube, and the fine density was obtained with a foam density of 2.5 ⁇ 10 4 pieces / mm 2 or more. A glass with bubbles was obtained. Moreover, from these results, it was shown that fine bubbles can be contained in glass by pressurizing the glass melt to 3 MPa or more regardless of the glass system. In the glasses of Examples 1 to 3, no bubbles were visually recognized when observed with the naked eye, and the glass had good appearance.
  • Example 4 was atmospheric pressure dissolution, and even when stirring and gas-liquid mixing at a rotational speed of 500 rpm, only bubbles having a small bubble density and a large bubble diameter were obtained. And when the glass of Example 4 was observed with the naked eye, bubbles were visually recognized and the appearance was inferior. In Example 5, bubbles were not observed by SEM observation of the plate-like glass sample.
  • the thermal conductivity decreases as the bubble diameter decreases and the bubble density increases.
  • the thermal conductivity (0.62 W / m ⁇ K) of the glass of Example 3 is the thermal conductivity (0. 72 W / m ⁇ K).
  • the thermal conductivity (0.71 W / m ⁇ K) of the glass of Example 5 in which bubbles were not observed is also an example.
  • the thermal conductivity (0.62 W / m ⁇ K) of the glass No. 3 was significantly low.
  • Example 6 the glass of Example 6 in which fine bubbles were contained at a bubble density of 2.5 ⁇ 10 4 pieces / mm 2 or more showed a large quantum conversion yield as compared with the glass of Example 7, It was confirmed that the fluorescent glass contributes to the improvement of characteristics.
  • the fine bubble glass of the present invention is obtained in the same manner as in the above examples.
  • the glass of the present invention has good appearance from any direction while containing bubbles.
  • the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of the bubbles. It can develop properties. Therefore, the application to various uses, such as an optical element, an electrical element, a thermoelectric conversion element, an acoustic element, and a lightweight heat insulating material, is expected.

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Abstract

The present invention relates to glass having bubbles wherein, when a cross section of the glass is viewed, the number of bubbles in the cross section is 1.0×102/mm2 or more, a diameter of the bubbles is 50 ìm or less, and an aspect ratio is 1.25 or less. This glass has good external appearance from any direction while having bubbles.

Description

微小な気泡を含有するガラス及びその製造方法Glass containing fine bubbles and method for producing the same
　本発明は、微小な気泡を含有するガラスおよびその製造方法に関する。 The present invention relates to glass containing minute bubbles and a method for producing the same.
　ガラス中の泡（気泡）は、通常は欠点として認識される。したがって、通常は、泡を含まないガラスが望まれている。
　一方で、従来から、多孔質ガラスや発泡ガラスといった、ガラス中に細孔や泡が内在するガラス及びその製造方法も提案されている。 Bubbles (bubbles) in the glass are usually recognized as defects. Therefore, usually glass without bubbles is desired.
On the other hand, conventionally, a glass such as porous glass and foamed glass in which pores and bubbles are present in the glass and a method for producing the same have also been proposed.
　例えば、特許文献１には、ホウ硅酸ガラスを分相させた後、酸処理を施すことにより、ガラス中に細孔を有する多孔質ガラスが得られることが記載されている。 For example, Patent Document 1 describes that porous glass having pores in glass can be obtained by subjecting borosilicate glass to phase separation and then acid treatment.
　また、特許文献２には、微粉砕したガラスにＳｉＣ等の発泡剤を混入させた後、それらを成型及び焼成して発泡ガラスを得ることが記載されている。 Patent Document 2 describes that after a foaming agent such as SiC is mixed into finely pulverized glass, they are molded and fired to obtain foamed glass.
米国特許第２１０６７４４号明細書U.S. Pat.No. 2,106,744 米国特許第３９７５１７４号明細書U.S. Pat. No. 3,975,174
　しかしながら、特許文献１に記載の多孔質ガラス中の細孔はアスペクト比が大きいため、当該多孔質ガラスは異方性を有する。したがって、当該多孔質ガラスを外部から視認した際に、視認する方向によっては細孔が肉眼で観察されるため、気泡が視認されることが好ましくない用途には不向きである。また、当該多孔質ガラスを製造するには酸処理が必要となるため、分相ガラス中の酸に溶出する相が溶出する際に、多量の酸の使用や廃液処理が必要であり、また、酸に溶出する相を溶出させるために要する時間が長く、生産性の面でも課題がある。 However, since the pores in the porous glass described in Patent Document 1 have a large aspect ratio, the porous glass has anisotropy. Therefore, when the porous glass is viewed from the outside, the pores are observed with the naked eye depending on the viewing direction. Moreover, since acid treatment is required to produce the porous glass, when a phase that elutes into the acid in the phase-separated glass elutes, it is necessary to use a large amount of acid and waste liquid treatment, It takes a long time to elute the phase that elutes in the acid, and there is a problem in terms of productivity.
　また、特許文献２に記載の発泡ガラスでは、得られる発泡ガラス中の気泡のアスペクト比はほぼ１であるが、当該発泡ガラスの製造方法では、気泡径や気泡分布の制御が困難であり、気泡が視認されない外観性の良好なガラスを得ることは困難である。 Further, in the foamed glass described in Patent Document 2, the aspect ratio of the bubbles in the obtained foamed glass is approximately 1, but in the method for producing the foamed glass, it is difficult to control the bubble diameter and the bubble distribution. It is difficult to obtain a glass with good appearance that is not visually recognized.
　前記従来の課題を鑑みて、本発明は、気泡を含有しながらも、任意の方向からの外観性が良好であるガラス及びその製造方法を提供することを目的とする。なお、本明細書において、「外観性が良好であるガラス」とは、外部から肉眼で観察した際に気泡が視認されないガラスを意味する。 In view of the conventional problems described above, an object of the present invention is to provide a glass having a good appearance from an arbitrary direction while containing bubbles, and a method for producing the same. In the present specification, “glass having good appearance” means a glass in which bubbles are not visually recognized when observed with the naked eye from the outside.
　本発明者らは、前記課題を解決するために鋭意検討を重ねた結果、以下のガラスにより前記課題を解決できることを見出し、本発明を完成するに至った。 As a result of intensive studies in order to solve the above problems, the present inventors have found that the above problems can be solved by the following glass, and have completed the present invention.
　すなわち、本発明は、気泡を含有するガラスであって、前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が１．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が５０μｍ以下であり、アスペクト比が１．２５以下であるガラスを提供する。 That is, the present invention is a glass containing bubbles, and when the cross section of the glass is observed, the number of the bubbles in the cross section is 1.0 × 10 2 pieces / mm 2 or more, and Provided is a glass having a bubble diameter of 50 μm or less and an aspect ratio of 1.25 or less.
　また、本発明は、０．２～１００ＭＰａに加圧しながらガラスを溶解させる溶解工程、溶解された前記ガラスを冷却する冷却工程、及び、冷却された前記ガラスを徐冷する徐冷工程を備えるガラスの製造方法をも提供する。 The present invention also includes a melting step of melting glass while being pressurized to 0.2 to 100 MPa, a cooling step of cooling the melted glass, and a slow cooling step of slowly cooling the cooled glass A manufacturing method is also provided.
　本発明のガラスに含有される、気泡径が５０μｍ以下かつアスペクト比が１．２５以下の気泡は、任意の方向からの肉眼による観察では視認されない微小な気泡である。したがって、前記構成を備える本発明のガラスは、気泡を含有しながらも、任意の方向から気泡が視認されず、外観性が良好である。
　また、本発明のガラスは、前記気泡の気泡径、アスペクト比及び個数を適宜調整することにより、軽量性、断熱性、遮音性、電気的絶縁性、熱電効果、光散乱制御性等の種々の特性を発現しうる。したがって、光学素子、電気的素子、熱電変換素子、音響素子、軽量断熱材等の種々の用途への応用が期待される。光学素子として具体的には、波長選択フィルターや発光素子、太陽電池などが、電気的素子として具体的には絶縁体やキャパシター、２次電池などが挙げられる。 Bubbles having a bubble diameter of 50 μm or less and an aspect ratio of 1.25 or less, which are contained in the glass of the present invention, are minute bubbles that are not visible by observation with the naked eye from an arbitrary direction. Therefore, the glass of the present invention having the above-described configuration has good appearance, since bubbles are not visually recognized from any direction while containing bubbles.
In addition, the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of the bubbles. It can develop properties. Therefore, the application to various uses, such as an optical element, an electrical element, a thermoelectric conversion element, an acoustic element, and a lightweight heat insulating material, is expected. Specific examples of the optical element include a wavelength selection filter, a light emitting element, and a solar battery, and specific examples of the electric element include an insulator, a capacitor, and a secondary battery.
　また、本発明のガラスの製造方法によれば、複雑な工程を要することなく、本発明のガラスを効率よく製造することができる。 Moreover, according to the glass manufacturing method of the present invention, the glass of the present invention can be efficiently manufactured without requiring a complicated process.
図１は、例１（実施例）に係るガラスの断面ＳＥＭ画像である。FIG. 1 is a cross-sectional SEM image of glass according to Example 1 (Example). 図２は、例２（実施例）に係るガラスの断面ＳＥＭ画像である。FIG. 2 is a cross-sectional SEM image of the glass according to Example 2 (Example).
　以下、本発明の実施形態について詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
＜ガラス＞
　本発明のガラスは、気泡を含有するガラスであって、前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が１．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が５０μｍ以下であり、アスペクト比が１．２５以下である。
　なお、以下においては、気泡径が５０μｍ以下であり、かつアスペクト比が１．２５以下である気泡を、「ファインバブル」ということがある。 <Glass>
The glass of the present invention is a glass containing bubbles, and when the cross section of the glass is observed, the number of the bubbles in the cross section is 1.0 × 10 2 pieces / mm 2 or more, and The bubble diameter is 50 μm or less, and the aspect ratio is 1.25 or less.
In the following, bubbles having a bubble diameter of 50 μm or less and an aspect ratio of 1.25 or less may be referred to as “fine bubbles”.
　ここで、本発明における気泡の気泡径とは、ガラスを切断した断面を走査型電子顕微鏡（ＳＥＭ）で観察して得られるＳＥＭ画像から読み取られる気泡径を表す。 Here, the bubble diameter of the bubble in the present invention represents a bubble diameter read from an SEM image obtained by observing a cross section of the glass with a scanning electron microscope (SEM).
　また、本発明における気泡のアスペクト比とは、ガラスを切断した断面を走査型電子顕微鏡（ＳＥＭ）で観察して得られるＳＥＭ画像から、気泡の長径と短径を読み取り、長径／短径として算出される値を表す。 The aspect ratio of the bubble in the present invention is calculated as a major axis / minor axis by reading the major axis and minor axis of a bubble from an SEM image obtained by observing a cross section of the glass with a scanning electron microscope (SEM). Represents the value to be
　気泡径が５０μｍ以下かつアスペクト比が１．２５以下の気泡（ファインバブル）は、任意の方向からガラスを肉眼で観察した際に視認されることがない。本発明のガラスは、その断面を観察したときに、前記断面におけるファインバブルの個数が１．０×１０２個／ｍｍ２以上であり、気泡を含有しながらも、任意の方向からの外観性が良好である。 Bubbles having a bubble diameter of 50 μm or less and an aspect ratio of 1.25 or less (fine bubbles) are not visually recognized when the glass is observed with the naked eye from an arbitrary direction. When the cross section of the glass of the present invention is observed, the number of fine bubbles in the cross section is 1.0 × 10 2 / mm 2 or more, and the appearance from any direction is contained while containing bubbles. Is good.
　なお、気泡の気泡径、気泡のアスペクト比、及び気泡の個数は、本発明のガラスを製造する際の、ガラスの溶解時の加圧条件、溶解温度、発泡剤、雰囲気、冷却時の冷却速度、徐冷条件等の各条件を適宜調整することにより、調整することができる。 It should be noted that the bubble diameter, bubble aspect ratio, and number of bubbles are the pressure conditions during melting of the glass, melting temperature, blowing agent, atmosphere, and cooling rate during cooling when manufacturing the glass of the present invention. It can be adjusted by appropriately adjusting each condition such as a slow cooling condition.
　本発明のガラスにおいて、任意の方向からの良好な外観性を得る観点から、ファインバブルの気泡径は５０μｍ以下であり、好ましくは２０μｍ以下であり、より好ましくは１μｍ以下であり、さらに好ましくは５００ｎｍ以下であり、特に好ましくは２００ｎｍ以下である。また、ファインバブルの気泡径の下限は特に限定されるものではないが、種々の特性発現と気泡密度の観点からは、例えば、１ｎｍ以上である。 In the glass of the present invention, from the viewpoint of obtaining a good appearance from any direction, the fine bubble has a bubble diameter of 50 μm or less, preferably 20 μm or less, more preferably 1 μm or less, and even more preferably 500 nm. Or less, particularly preferably 200 nm or less. Moreover, the lower limit of the bubble diameter of the fine bubble is not particularly limited, but is 1 nm or more, for example, from the viewpoint of various characteristics and bubble density.
　また、本発明のガラスにおいて、任意の方向からの良好な外観性を得る観点から、ファインバブルのアスペクト比は１．２５以下であり、好ましくは１．２以下であり、より好ましくは１．１５以下であり、さらに好ましくは１．１以下であり、あるいはファインバブルは真円（アスペクト比が１）であってもよい。 In the glass of the present invention, the fine bubble has an aspect ratio of 1.25 or less, preferably 1.2 or less, more preferably 1.15, from the viewpoint of obtaining good appearance from any direction. Or less, more preferably 1.1 or less, or the fine bubble may be a perfect circle (aspect ratio is 1).
　また、本発明のガラスにおいて、ガラスの断面を観察したときの、当該断面におけるファインバブルの個数（以下、泡密度ともいう）は、１．０×１０２個／ｍｍ２以上であり、好ましくは１．０×１０３個／ｍｍ２以上であり、より好ましくは５．０×１０５個／ｍｍ２以上である。また、前記泡密度の上限は特に限定されるものではないが、製造上の観点からは、例えば、１．０×１０１２個／ｍｍ２以下である。 In the glass of the present invention, when the cross section of the glass is observed, the number of fine bubbles in the cross section (hereinafter also referred to as bubble density) is 1.0 × 10 2 pieces / mm 2 or more, preferably 1.0 × 10 3 pieces / mm 2 or more, more preferably 5.0 × 10 5 pieces / mm 2 or more. Moreover, although the upper limit of the said foam density is not specifically limited, From a viewpoint on manufacture, it is 1.0 * 10 < 12 > pieces / mm < 2 > or less, for example.
　また、本発明のガラスは、ファインバブルの気泡径、アスペクト比及び個数を適宜調整することにより、軽量性、断熱性、遮音性、電気的絶縁性、熱電効果、光散乱制御性等の種々の特性を発現しうる。 Further, the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of fine bubbles. It can develop properties.
　たとえば、本発明のガラスの好適な一態様として、前記ガラスの断面を観察したときの、前記断面における気泡の個数が５．０×１０４個／ｍｍ２以上であり、かつ、前記気泡の気泡径が５００ｎｍ以下であるガラスは、平均自由工程が小さくなるために、ガラスの熱伝導率が低く、高い断熱性を有する。本態様においては、気泡径が２００ｎｍ以下、かつ泡密度が５．０×１０５個／ｍｍ２以上であることがより好ましく、気泡径が１００ｎｍ以下、かつ泡密度が１．０×１０６個／ｍｍ２以上であることがさらに好ましい。なお、本態様においては、気泡のアスペクト比は、前記した範囲内である。 For example, as a preferred embodiment of the glass of the present invention, the number of bubbles in the cross section when the cross section of the glass is observed is 5.0 × 10 4 pieces / mm 2 or more, and the bubbles of the bubbles Glass having a diameter of 500 nm or less has a low mean thermal process, so that the glass has low thermal conductivity and high heat insulating properties. In this embodiment, it is more preferable that the bubble diameter is 200 nm or less and the bubble density is 5.0 × 10 5 pieces / mm 2 or more, the bubble diameter is 100 nm or less and the bubble density is 1.0 × 10 6 pieces. / Mm 2 or more is more preferable. In this aspect, the aspect ratio of the bubbles is within the above-described range.
　また、本発明のガラスの別の好適な一態様として、前記ガラスの断面を観察したときの、前記断面における気泡の個数が２．０×１０２個／ｍｍ２以上であり、かつ前記気泡の気泡径が２０μｍ以下であるガラスは、気孔率が大きいために、ガラスの比重が小さく、軽量である。本態様においては、気泡径が１μｍ以下、かつ気泡の個数が５．０×１０４個／ｍｍ２以上であることがより好ましく、気泡径が５００ｎｍ以下、かつ泡密度が２．０×１０５個／ｍｍ２以上であることがさらに好ましい。なお、軽量かつ透明なガラスを得たい場合、気泡径は小さく、泡密度は大きいほど望ましいが、気孔率に対し、気泡径は３乗で効くために気泡径が小さくなるほどより多くの気泡を導入する必要が生じ、製造の観点でも非効率である。典型的には、気泡径は２０ｎｍ以上、かつ泡密度は２．０×１０９個／ｍｍ２以下である。なお、本態様においては、気泡のアスペクト比は、前記した範囲内である。 Further, as another preferred embodiment of the glass of the present invention, the number of bubbles in the cross section when the cross section of the glass is observed is 2.0 × 10 2 pieces / mm 2 or more, and Glass having a bubble diameter of 20 μm or less has a high porosity, and thus has a low specific gravity and is lightweight. In this embodiment, it is more preferable that the bubble diameter is 1 μm or less and the number of bubbles is 5.0 × 10 4 / mm 2 or more, the bubble diameter is 500 nm or less, and the bubble density is 2.0 × 10 5. It is more preferable that the number of particles / mm 2 or more. In order to obtain lightweight and transparent glass, it is desirable that the bubble diameter is small and the bubble density is large. However, since the bubble diameter works as a third power against the porosity, more bubbles are introduced as the bubble diameter becomes smaller. This is inefficient in terms of manufacturing. Typically, the bubble diameter is 20 nm or more and the bubble density is 2.0 × 10 9 cells / mm 2 or less. In this aspect, the aspect ratio of the bubbles is within the above-described range.
　また、本発明のガラスの別の好適な一態様として、前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が１．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が１５μｍ以下であり、アスペクト比が１．２以下であるガラスは、その気泡径に応じて紫外光から赤外光に対し、所定の波長で散乱効率を高めることができるため、光学素子として好適である。本態様において、より好ましくは、気泡径が１０μｍ以下、かつアスペクト比が１．１以下であり、かつ泡密度が２．０×１０２個／ｍｍ２以上である。例えば紫外光をカットしたければ、ガラスの屈折率に応じて、気泡径を１００～５５０ｎｍの範囲から、かつ泡密度を２．０×１０４～１．０×１０６個／ｍｍ２の範囲から選択すればよい。また、赤外を透過するガラスにおいて、中赤外（３～５μｍ）以下の波長をカットしたければ、気泡径が７μｍ以下であり、かつ泡密度が２．０×１０２個／ｍｍ２以上であることが好ましい。 Further, as another preferred embodiment of the glass of the present invention, the number of the bubbles in the cross section when the cross section of the glass is observed is 1.0 × 10 2 pieces / mm 2 or more, and Glass having a bubble diameter of 15 μm or less and an aspect ratio of 1.2 or less can increase scattering efficiency at a predetermined wavelength from ultraviolet light to infrared light depending on the bubble diameter. It is suitable as an optical element. In this embodiment, more preferably, the bubble diameter is 10 μm or less, the aspect ratio is 1.1 or less, and the bubble density is 2.0 × 10 2 pieces / mm 2 or more. For example, if you want to cut ultraviolet light, depending on the refractive index of the glass, the bubble diameter is in the range of 100 to 550 nm and the bubble density is in the range of 2.0 × 10 4 to 1.0 × 10 6 pieces / mm 2 . You can choose from. In addition, in a glass that transmits infrared rays, if it is desired to cut wavelengths below mid-infrared (3 to 5 μm), the bubble diameter is 7 μm or less and the bubble density is 2.0 × 10 2 pieces / mm 2 or more. It is preferable that
　本発明のガラスは、好ましくは、気泡径が５０μｍ以下であり、かつアスペクト比が１．２５以下である気泡以外の気泡を含有しない。このような気泡を含有すると、ガラスを任意の方向から肉眼で観察した際に当該気泡が視認されるおそれがあり、その結果、ガラスの外観性が悪くなるおそれがある。 The glass of the present invention preferably contains no bubbles other than bubbles having a bubble diameter of 50 μm or less and an aspect ratio of 1.25 or less. When such bubbles are contained, when the glass is observed with the naked eye from an arbitrary direction, the bubbles may be visually recognized. As a result, the appearance of the glass may be deteriorated.
　また、本発明のガラスに用いられるガラスの種類は特に限定されず、公知の各種ガラスから適宜選択して適用することができる。たとえば、ソーダライムガラス、アルミノシリケートガラス、ボロシリケートガラス、リン酸ガラス、フツリン酸ガラス、ハライドガラス、カルコゲナイトガラス等が例示される。 Moreover, the kind of glass used for the glass of the present invention is not particularly limited, and can be appropriately selected and applied from various known glasses. Examples thereof include soda lime glass, aluminosilicate glass, borosilicate glass, phosphate glass, fluorophosphate glass, halide glass, and chalcogenite glass.
　また、本発明のガラスの形状は特に制限されるものではなく、適用される用途等に応じて、板状、ブロック状、管状、ファイバ状等の種々の形状をとりうる。 Further, the shape of the glass of the present invention is not particularly limited, and can take various shapes such as a plate shape, a block shape, a tubular shape, and a fiber shape according to the application to be applied.
　また、本発明のガラスには、化学強化処理、物理強化処理等の強化処理を適宜施してもよい。強化処理の手法としては、公知の手法を特に制限なく採用することができる。強化処理を施した強化ガラスは、軽量高断熱窓ガラス、自動車用窓ガラス等に用いることができる。 Further, the glass of the present invention may be appropriately subjected to tempering treatment such as chemical tempering treatment and physical tempering treatment. A publicly known method can be employed without particular limitation as the strengthening processing method. The tempered glass subjected to the tempering treatment can be used for a light and highly insulated window glass, an automobile window glass and the like.
＜ガラスの製造方法＞
　本発明のガラスの製造方法は、０．２～１００ＭＰａに加圧しながらガラスを溶解させる溶解工程、溶解された前記ガラスを冷却する冷却工程、及び、冷却された前記ガラスを徐冷する徐冷工程を備える。本発明のガラスの製造方法を実施することにより、本発明のガラスを容易に製造することが可能である。
　溶融ガラスの表面張力σは比較的大きく、溶融ガラス中に小さい泡径Ｄの気泡が発生した場合、気泡内部と気泡周囲との圧力差ΔＰが大きいことにより、小さい泡径Ｄの気泡は、ヤングラプラスの式（ΔＰ＝４σ／Ｄ）に従い、瞬時に圧壊される。
　ここで、本発明者らは、鋭意検討を重ねた結果、所定の圧力で加圧しながらガラスを溶解させることにより、溶融ガラス中に発生した小さい泡径の気泡（特にファインバブル）を圧壊させることなく、所定の気泡個数で所定の気泡径で所定のアスペクト比のファインバブルを溶融ガラス中に維持させ、内在させることができることを見出した。 <Glass manufacturing method>
The glass production method of the present invention includes a melting step for melting glass while being pressurized to 0.2 to 100 MPa, a cooling step for cooling the melted glass, and a slow cooling step for gradually cooling the cooled glass. Is provided. By carrying out the glass manufacturing method of the present invention, the glass of the present invention can be easily manufactured.
The surface tension σ of the molten glass is relatively large, and when bubbles having a small bubble diameter D are generated in the molten glass, the bubbles having a small bubble diameter D are reduced by the pressure difference ΔP between the inside of the bubbles and the periphery of the bubbles. According to Laplace's formula (ΔP = 4σ / D), it is instantaneously crushed.
Here, as a result of intensive investigations, the present inventors are able to crush bubbles (especially fine bubbles) with a small bubble diameter generated in the molten glass by melting the glass while applying pressure at a predetermined pressure. However, it has been found that fine bubbles having a predetermined number of bubbles and a predetermined bubble diameter and a predetermined aspect ratio can be maintained and contained in the molten glass.
（溶解工程）
　本発明のガラスの製造方法においては、まず、０．２～１００ＭＰａに加圧しながらガラスを溶解させる。溶解工程の際の圧力が０．２ＭＰａ以上であると、ガラス融体中に効率的にファインバブルを含有させることができる。当該圧力は、０．３ＭＰａ以上であることが好ましく、０．５ＭＰａ以上であることがより好ましい。一方、溶解工程の際の圧力が１００ＭＰａより大きいと、製造時の耐圧容器が限定されコストも莫大となるおそれがある。当該圧力は、５０ＭＰａ以下であることが好ましく、１０ＭＰａ以下であることがより好ましい。 (Dissolution process)
In the glass production method of the present invention, first, the glass is melted while being pressurized to 0.2 to 100 MPa. When the pressure during the melting step is 0.2 MPa or more, fine bubbles can be efficiently contained in the glass melt. The pressure is preferably 0.3 MPa or more, and more preferably 0.5 MPa or more. On the other hand, if the pressure during the melting step is greater than 100 MPa, the pressure-resistant container at the time of production is limited, and the cost may be enormous. The pressure is preferably 50 MPa or less, and more preferably 10 MPa or less.
　加圧しながらガラスを溶解する方法としては、特に限定されるものではないが、例えば、以下の方法が挙げられる。
　まず、ガラス原料を、石英管等の適宜な容器中に封入する。この際、真空排気しながら封入してもよい。封入時に真空排気を行う場合の圧力は、例えば１０～３０Ｐａである。
　つづいて、ガラス原料を封入した容器を、封入されたガラス原料の溶解温度よりも高い温度まで加熱した状態で、所定時間保持する。保持時間は、例えば２～４８時間である。このようにすると、温度上昇に伴ってガラス原料が溶解され、ガラス原料中から蒸気が生成して、各原料の蒸気圧に応じて容器内の内圧が上昇する。この状態を所定時間保持することにより、溶解したガラス中にファインバブルが内包された状態となる。
　あるいは、あらかじめ一般的な溶解手法でガラスを溶解し、冷却してカレットを作製後、そのカレットを耐圧容器に入れ、昇温してガラスが融液に達してから所望のガスを導入して加圧させてもよい。さらに加圧を促進するため、所望の蒸気圧の高い発泡剤を添加してもよい。所望のガスや発泡剤とは、例えばソーダライムガラス、アルミノシリケートガラス、ボロシリケートガラス、リン酸ガラスなどに対し、ガスであれば酸素、二酸化炭素、硫酸ガス等が、発泡剤として炭酸塩、硫酸塩、フッ化物、塩化物等が挙げられる。発泡剤であれば、ガラス全質量を１００質量％として、０．１～１０質量％の範囲で添加するのが好ましい。より好ましくは０．２～５質量％、さらに好ましくは０．５～３質量％である。また、フツリン酸ガラス、ハライドガラス、カルコゲナイドガラスに対し、ガスであればハライドガス、不活性ガスやカルコゲンガスが、発泡剤としてフッ化物、塩化物、カルコゲンが挙げられる。
　溶解温度は特に限定されないが、好ましくは６００～１７００℃の範囲である。溶解温度の上限温度は、容器の耐熱温度以下であることが好ましい。容器に石英管を使用する場合は、１０００℃以下が好ましい。より好ましくは９５０℃以下、さらに好ましくは９００℃以下である。一方、製造するガラスが失透しないことを考慮すると、溶解温度は、そのガラスの失透温度以上であることが好ましい。 Although it does not specifically limit as a method to melt | dissolve glass, applying, for example, the following methods are mentioned.
First, the glass raw material is sealed in an appropriate container such as a quartz tube. At this time, it may be sealed while evacuating. The pressure when evacuating at the time of sealing is, for example, 10 to 30 Pa.
Subsequently, the container enclosing the glass raw material is held for a predetermined time while being heated to a temperature higher than the melting temperature of the encapsulated glass raw material. The holding time is, for example, 2 to 48 hours. If it does in this way, a glass raw material will be melt | dissolved with a temperature rise, a vapor | steam will produce | generate from glass raw material, and the internal pressure in a container will rise according to the vapor pressure of each raw material. By maintaining this state for a predetermined time, fine bubbles are included in the melted glass.
Alternatively, the glass is melted by a general melting method in advance and cooled to prepare a cullet, and then the cullet is placed in a pressure vessel, and the temperature is raised and the glass reaches a melt, and then a desired gas is introduced and added. You may make it press. Furthermore, in order to accelerate the pressurization, a foaming agent having a desired high vapor pressure may be added. Desired gases and foaming agents are, for example, soda lime glass, aluminosilicate glass, borosilicate glass, phosphate glass, etc., in the case of gas, oxygen, carbon dioxide, sulfuric acid gas, etc. Examples include salts, fluorides, and chlorides. In the case of a foaming agent, it is preferable to add in the range of 0.1 to 10% by mass with the total mass of glass being 100% by mass. More preferably, the content is 0.2 to 5% by mass, and still more preferably 0.5 to 3% by mass. Moreover, with respect to fluorophosphate glass, halide glass, and chalcogenide glass, if it is gas, halide gas, inert gas, and chalcogen gas will be mentioned, and fluoride, chloride, and chalcogen as foaming agents.
The melting temperature is not particularly limited, but is preferably in the range of 600 to 1700 ° C. The upper limit temperature of the melting temperature is preferably not more than the heat resistant temperature of the container. When a quartz tube is used for the container, it is preferably 1000 ° C. or lower. More preferably, it is 950 degrees C or less, More preferably, it is 900 degrees C or less. On the other hand, considering that the glass to be manufactured does not devitrify, the melting temperature is preferably equal to or higher than the devitrification temperature of the glass.
（冷却工程）
　溶解工程につづいて、ファインバブルを含む溶解したガラスを冷却する冷却工程を行う。これにより、溶解したガラスがファインバブルを内包した状態で冷却固化され、ファインバブルがガラス内部に保持される。冷却工程としては、公知の手法を適宜採用することができる。 (Cooling process)
Following the melting step, a cooling step for cooling the melted glass containing fine bubbles is performed. Thereby, the melted glass is cooled and solidified in a state of enclosing the fine bubbles, and the fine bubbles are held inside the glass. As the cooling step, a known method can be appropriately adopted.
　冷却工程における冷却速度は、特に限定されるものではないが、溶解ガラスがファインバブルを内包した状態を良好に保持しながらガラスを冷却固化させるためには、冷却速度は１００℃／ｍｉｎ以上であることが好ましく、３００℃／ｍｉｎ以上であることがより好ましい。なお、冷却速度の上限も特に限定されるものではないが、溶解設備や耐圧容器への負荷低減の観点からは、好ましくは６０００℃／ｍｉｎ以下であり、より好ましくは１０００℃／ｍｉｎ以下である。 The cooling rate in the cooling step is not particularly limited, but the cooling rate is 100 ° C./min or more in order to cool and solidify the glass while maintaining the state in which the molten glass contains fine bubbles. It is preferably 300 ° C./min or more. Although the upper limit of the cooling rate is not particularly limited, it is preferably 6000 ° C./min or less, more preferably 1000 ° C./min or less from the viewpoint of reducing the load on the melting equipment and the pressure vessel. .
（徐冷工程）
　冷却工程につづいて、ガラスの歪みを除去するために、ガラスを徐冷する徐冷工程を行う。徐冷工程としては、公知の手法を適宜採用することができる。徐冷工程における冷却速度は、特に限定されるものではないが、ガラスの残留歪を除去し、破損を防ぐ観点からは、好ましくは１００℃／ｍｉｎ以下であり、より好ましくは１０℃／ｍｉｎ以下である。 (Slow cooling process)
Following the cooling step, a slow cooling step of slow cooling the glass is performed to remove the distortion of the glass. As the slow cooling step, a known method can be appropriately employed. The cooling rate in the slow cooling step is not particularly limited, but is preferably 100 ° C./min or less, more preferably 10 ° C./min or less, from the viewpoint of removing residual strain of glass and preventing breakage. It is.
（その他の工程）
　なお、本発明のガラスの製造方法は、上記溶解工程、冷却工程及び徐冷工程に加えて、その他の工程をさらに備えていてもよい。たとえば、溶解工程と冷却工程の間に、ガラスを所望の形状に成形する成形工程や、ガラスの清澄工程を適宜備えていてもよい。なお、成形工程や清澄工程としては、公知の手法を適宜採用することができる。 (Other processes)
The glass manufacturing method of the present invention may further include other steps in addition to the melting step, the cooling step, and the slow cooling step. For example, between the melting step and the cooling step, a forming step for forming the glass into a desired shape and a glass refining step may be appropriately provided. In addition, a well-known method is employable suitably as a shaping | molding process or a refining process.
　以下、実施例に基づき本発明をさらに詳細に説明するが、本発明はこれら実施例により特に限定されるものではない。以下において、例１～３及び６は実施例であり、例４及び７は比較例であり、例５は参考例である。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not particularly limited by these examples. In the following, Examples 1 to 3 and 6 are Examples, Examples 4 and 7 are Comparative Examples, and Example 5 is a Reference Example.
（例１）
　原子％表記で、Ｇｅ　４％、Ｓｂ　１０％、Ｓ　８６％の組成（以下、ガラス組成１ともいう）となるようにガラス原料を混合し、１０ｇの原料バッチを得た。また、内径８ｍｍの石英管の片端を酸水素バーナーで加熱して封止して石英ガラスアンプルを作製した後、イソプロピルアルコール（ＩＰＡ）で洗浄し、６００℃で減圧乾燥を行った。
　つづいて、石英ガラスアンプル中に前記原料バッチを入れて押圧した後、１０～３０Ｐａで真空排気しながら開口部を酸水素バーナーで加熱して、石英ガラスアンプルを封管した。 (Example 1)
Glass raw materials were mixed so as to have a composition of Ge 4%, Sb 10%, and S 86% (hereinafter also referred to as glass composition 1) in terms of atomic% to obtain a 10 g raw material batch. Further, one end of a quartz tube having an inner diameter of 8 mm was heated and sealed with an oxyhydrogen burner to produce a quartz glass ampule, which was then washed with isopropyl alcohol (IPA) and dried at 600 ° C. under reduced pressure.
Subsequently, the raw material batch was placed in a quartz glass ampule and pressed, and then the opening was heated with an oxyhydrogen burner while evacuating at 10 to 30 Pa to seal the quartz glass ampule.
　原料バッチが封入された石英ガラスアンプルを予め２００℃に昇温されている溶融炉内に入れ、２℃／ｍｉｎの昇温速度で８００℃まで昇温させることによりガラス原料を溶解させ、１時間保持した。ここで、硫黄の蒸気圧曲線から類推される石英管内の内圧は、約８ＭＰａであった。 The quartz glass ampule in which the raw material batch is sealed is placed in a melting furnace that has been heated to 200 ° C. in advance, and the glass raw material is melted by raising the temperature to 800 ° C. at a temperature rising rate of 2 ° C./min. Retained. Here, the internal pressure in the quartz tube estimated from the vapor pressure curve of sulfur was about 8 MPa.
　次に、封管された石英ガラスアンプルを大気放冷することにより、石英ガラスアンプル中の溶融ガラスを冷却固化させた。冷却速度は約３０００℃／ｍｉｎであった。 Next, the sealed quartz glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified. The cooling rate was about 3000 ° C./min.
　つづいて、封管された石英ガラスアンプルを２３０℃に昇温されている電気炉に入れ、－０．５℃／ｍｉｎの降温速度で室温まで徐冷して、例１のガラスを作製した。 Subsequently, the sealed quartz glass ampule was placed in an electric furnace heated to 230 ° C., and slowly cooled to room temperature at a temperature lowering rate of −0.5 ° C./min to produce the glass of Example 1.
　次に、封管された石英ガラスアンプルから取り出したガラスを切断し、研磨することにより、厚み約１ｍｍの板状のガラスサンプルを３枚作製した。さらに、３枚の板状のガラスサンプルを取り出した後のガラスの一部を粉砕して得られたガラス粉末のガラス転移点Ｔｇを、示差熱分析計（リガク社製、商品名：ＴＧ８１１０）を使用して測定したところ、２２５℃であった。 Next, the glass taken out from the sealed quartz glass ampule was cut and polished to prepare three plate-like glass samples having a thickness of about 1 mm. Further, the glass transition point Tg of the glass powder obtained by pulverizing a part of the glass after taking out the three plate-like glass samples is measured with a differential thermal analyzer (trade name: TG8110, manufactured by Rigaku Corporation). It was 225 degreeC when measured using.
（例２）
　例２においては、ガラス原料の原料バッチが封入された石英ガラスアンプルを予め２００℃に昇温されている溶融炉内に入れ、２℃／ｍｉｎの昇温速度で７００℃まで昇温させることによりガラス原料を溶解させ、２時間保持した以外は例１と同様にして、例２のガラスを作製した。ここで、硫黄の蒸気圧曲線から類推される石英管内の内圧は、約３ＭＰａであった。
　また、例２のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを３枚作製した。さらに、例１と同様にして例２のガラスのガラス転移点Ｔｇを測定したところ、２２４℃であった。 (Example 2)
In Example 2, a quartz glass ampoule in which a raw material batch of glass raw materials is enclosed is placed in a melting furnace that has been heated to 200 ° C. in advance, and the temperature is raised to 700 ° C. at a rate of 2 ° C./min. The glass of Example 2 was produced in the same manner as in Example 1 except that the glass raw material was dissolved and held for 2 hours. Here, the internal pressure in the quartz tube inferred from the vapor pressure curve of sulfur was about 3 MPa.
Further, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 2 in the same manner as in Example 1. Further, when the glass transition point Tg of the glass of Example 2 was measured in the same manner as in Example 1, it was 224 ° C.
（例３）
　原子％表記で、Ｐ　１４．３％、Ｍｇ　０．５％、Ｃａ　０．５％、Ｓｒ　２．８％、Ｂａ　８．２％、Ｌｉ　１６％、Ａｌ　７．２％、Ｙ　０．５％、Ｏ　３２．８％、Ｆ　１７．２％の組成（以下、ガラス組成２ともいう）となるように、６００ｇのガラス原料を混合した。これを白金坩堝中に入れた後、電気炉で９００℃まで加熱してガラス原料を溶融させ、さらに融液を回転ロールで急冷して、ガラスリボンを形成した。得られたガラスリボンをボールミルで粉砕し、目開き１５０μｍの網目を有する篩にかけ、ガラス粉末を得た。なお、このガラス粉末のガラス転移点Ｔｇは３７２℃であった。 (Example 3)
In terms of atomic%, P 14.3%, Mg 0.5%, Ca 0.5%, Sr 2.8%, Ba 8.2%, Li 16%, Al 7.2%, Y 0.5% 600 g of glass raw material was mixed so that the composition of O 32.8% and F 17.2% (hereinafter also referred to as glass composition 2) was obtained. After putting this in a platinum crucible, the glass raw material was melted by heating to 900 ° C. with an electric furnace, and the melt was quenched with a rotating roll to form a glass ribbon. The obtained glass ribbon was pulverized with a ball mill and passed through a sieve having a mesh with an opening of 150 μm to obtain glass powder. In addition, the glass transition point Tg of this glass powder was 372 degreeC.
　得られたガラス粉末を１０ｇ秤量し、さらにＢａＦ２を０．１ｇ添加してから例１と同様の石英ガラスアンプルに真空排気せずに封管し、２℃／ｍｉｎの昇温速度で９００℃まで昇温させることによりガラス粉末を溶解させ、１時間保持した。ここで、Ｆの臨界圧力から類推される石英管内の内圧は、約５ＭＰａであった。 10 g of the obtained glass powder was weighed, 0.1 g of BaF 2 was further added, and then the tube was sealed in a quartz glass ampoule similar to Example 1 without being evacuated, and the temperature was increased to 900 ° C. at a rate of 2 ° C./min. The glass powder was dissolved by raising the temperature to 1 hour and held for 1 hour. Here, the internal pressure in the quartz tube inferred from the critical pressure of F was about 5 MPa.
　次に、封管された石英ガラスアンプルを大気放冷することにより、石英ガラスアンプル中の溶融ガラスを冷却固化させた。冷却速度は約３０００℃／ｍｉｎであった。さらに、封管された石英ガラスアンプルを４００℃に昇温されている電気炉に入れ、－１℃／ｍｉｎの降温速度で室温まで徐冷して、例３のガラスを作製した。
　また、例３のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを３枚作製した。 Next, the sealed glass glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified. The cooling rate was about 3000 ° C./min. Further, the sealed quartz glass ampule was placed in an electric furnace heated to 400 ° C., and slowly cooled to room temperature at a temperature decrease rate of −1 ° C./min to produce the glass of Example 3.
Also, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 3 in the same manner as in Example 1.
（例４）
　例３と同様にして得られたガラス粉末を２００ｇ秤量して白金坩堝に入れ、さらにＢａＦ２を２ｇ添加してから電気炉で９００℃まで昇温してガラス粉末を溶解させ、３０分保持した。次に、白金スターラーを用いて５００ｒｐｍの回転速度で撹拌し、１０分清澄した後、白金坩堝ごと４００℃に昇温されている電気炉に入れて－１℃／ｍｉｎの降温速度で室温まで徐冷して、例４のガラスを作製した。
　また、例４のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを３枚作製した。 (Example 4)
200 g of the glass powder obtained in the same manner as in Example 3 was weighed and placed in a platinum crucible, and 2 g of BaF 2 was further added, and then the temperature was raised to 900 ° C. in an electric furnace to dissolve the glass powder and held for 30 minutes. . Next, after stirring for 10 minutes using a platinum stirrer at a rotational speed of 500 rpm, the platinum crucible is placed in an electric furnace heated to 400 ° C. and gradually cooled to room temperature at a temperature reduction rate of −1 ° C./min. Cooled to produce the glass of Example 4.
In addition, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 4 in the same manner as in Example 1.
（例５）
　例３と同様にしてガラス原料を３００ｇ混合して白金坩堝中に入れた後、電気炉で９００℃に加熱してガラス原料を溶解させ、１時間清澄させた。次に、白金坩堝ごと４００℃に昇温されている電気炉に入れて－１℃／ｍｉｎの降温速度で室温まで徐冷し、例５のガラスを作製した。
　また、例５のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを３枚作製した。 (Example 5)
In the same manner as in Example 3, 300 g of a glass raw material was mixed and placed in a platinum crucible, and then heated to 900 ° C. in an electric furnace to dissolve the glass raw material and clarify for 1 hour. Next, the platinum crucible was placed in an electric furnace heated to 400 ° C. and slowly cooled to room temperature at a temperature decrease rate of −1 ° C./min to produce the glass of Example 5.
Further, three plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 5 in the same manner as in Example 1.
（例６）
　例３と同様にして得られたガラス粉末を１０ｇ秤量し、さらにＢａＦ２を０．１ｇ、Ｅｕ２Ｏ３を０．２５ｇ添加してから例１と同様の石英ガラスアンプルに真空排気せずに封管し、２℃／ｍｉｎの昇温速度で８００℃まで昇温させることによりガラス粉末を溶解させ、１時間保持した。ここで、Ｆの臨界圧力から類推される石英管内の内圧は、約５ＭＰａであった。
　次に、封管された石英ガラスアンプルを大気放冷することにより、石英ガラスアンプル中の溶融ガラスを冷却固化させた。冷却速度は約３０００℃／ｍｉｎであった。さらに、封管された石英ガラスアンプルを４００℃に昇温されている電気炉に入れ、－１℃／ｍｉｎの降温速度で室温まで徐冷して、例６のガラスを作製した。
　また、例６のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを４枚作製した。 (Example 6)
10 g of the glass powder obtained in the same manner as in Example 3 was weighed, 0.1 g of BaF 2 and 0.25 g of Eu 2 O 3 were added, and the quartz glass ampoule similar to that in Example 1 was not evacuated. The glass powder was melted by sealing and heated to 800 ° C. at a rate of 2 ° C./min, and held for 1 hour. Here, the internal pressure in the quartz tube inferred from the critical pressure of F was about 5 MPa.
Next, the sealed glass glass ampule was allowed to cool to the atmosphere, whereby the molten glass in the quartz glass ampule was cooled and solidified. The cooling rate was about 3000 ° C./min. Further, the sealed quartz glass ampule was placed in an electric furnace heated to 400 ° C., and slowly cooled to room temperature at a temperature decrease rate of −1 ° C./min to produce the glass of Example 6.
Also, four plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 6 in the same manner as in Example 1.
（例７）
　例３と同様にして得られたガラス粉末２００ｇを秤量して白金坩堝に入れ、さらにＢａＦ２を２ｇ、Ｅｕ２Ｏ３を５ｇ添加してから電気炉で８００℃まで昇温してガラス粉末を溶解させ、３０分保持した。次に、白金スターラーを用いて５００ｒｐｍの回転速度で撹拌し、１０分清澄した後、白金坩堝ごと４００℃に昇温されている電気炉に入れて－１℃／ｍｉｎの降温速度で室温まで徐冷して、例７のガラスを作製した。
　また、例７のガラスからも、例１と同様にして厚み約１ｍｍの板状のガラスサンプルを４枚作製した。 (Example 7)
200 g of the glass powder obtained in the same manner as in Example 3 was weighed and placed in a platinum crucible, 2 g of BaF 2 and 5 g of Eu 2 O 3 were further added, and the temperature was raised to 800 ° C. in an electric furnace to obtain the glass powder. Dissolve and hold for 30 minutes. Next, after stirring for 10 minutes using a platinum stirrer at a rotational speed of 500 rpm, the platinum crucible is placed in an electric furnace heated to 400 ° C. and gradually cooled to room temperature at a temperature reduction rate of −1 ° C./min. It cooled and produced the glass of Example 7.
Also, four plate-like glass samples having a thickness of about 1 mm were produced from the glass of Example 7 in the same manner as in Example 1.
　各例のガラスについて、ガラスを切断、研磨して得られた３枚の板状の各ガラスサンプル表面の任意の３箇所を、走査型電子顕微鏡（ＳＥＭ）により観察し、合計９つのＳＥＭ画像を撮像した。
　気泡の個数（泡密度）は、上記９つのＳＥＭ画像のそれぞれにおいて気泡の個数を数え、その平均を１ｍｍ２あたりの気泡の個数に換算することにより算出した。その結果を表１および２に示す。
　また、気泡径（泡分布）として、上記９つのＳＥＭ画像において観察された気泡径の最小値と最大値を測定した。その結果を表１および２に示す。
　アスペクト比は、気泡の長径と短径をＳＥＭ画像から読み取り、長径／短径を算出して求めた。その結果を表１および２に示す。
　さらに、ガラスを任意の方向から肉眼で観察した際に、気泡が視認されるかどうかについて、表１および２にあわせて示した。 With respect to the glass of each example, arbitrary three places on the surface of each of the three plate-like glass samples obtained by cutting and polishing the glass were observed with a scanning electron microscope (SEM), and a total of nine SEM images were obtained. I took an image.
The number of bubbles (bubble density) was calculated by counting the number of bubbles in each of the nine SEM images and converting the average into the number of bubbles per mm 2 . The results are shown in Tables 1 and 2.
In addition, as the bubble diameter (bubble distribution), the minimum value and the maximum value of the bubble diameter observed in the nine SEM images were measured. The results are shown in Tables 1 and 2.
The aspect ratio was obtained by reading the major axis and minor axis of the bubbles from the SEM image and calculating the major axis / minor axis. The results are shown in Tables 1 and 2.
Further, Tables 1 and 2 show whether or not bubbles are visually recognized when the glass is observed with the naked eye from an arbitrary direction.
　図１に、例１のガラスから得られた板状のガラスサンプル表面のＳＥＭ画像の一つを示す。また、図２に、例２のガラスから得られた板状のガラスサンプル表面のＳＥＭ画像の一つを示す。 FIG. 1 shows one of the SEM images of the surface of the plate-like glass sample obtained from the glass of Example 1. FIG. 2 shows one of the SEM images of the surface of the plate-like glass sample obtained from the glass of Example 2.
　例１～５のガラスについて、比重をアルキメデス法により測定した。その結果を表１に示す。 For the glasses of Examples 1 to 5, the specific gravity was measured by the Archimedes method. The results are shown in Table 1.
　例１～５のガラスについて、φ５±０．０２ｍｍ、厚み１±０．０１ｍｍの精度でガラスを加工した後、京都電子工業社製のレーザーフラッシュ法熱物性測定装置ＬＦＡ－５０２を用いて熱伝導率を測定した。その結果を表１に示す。 For the glass of Examples 1 to 5, after processing the glass with an accuracy of φ5 ± 0.02 mm and thickness of 1 ± 0.01 mm, heat conduction was performed using a laser flash method thermal property measuring device LFA-502 manufactured by Kyoto Electronics Industry Co., Ltd. The rate was measured. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１より明らかなように、例１～３では、石英封管内で温度上昇に伴う蒸気圧上昇によってガラス融液が加圧され、２．５×１０４個／ｍｍ２以上の泡密度でファインバブルを内在したガラスが得られた。また、これらの結果より、ガラス系によらず、ガラス融液を３ＭＰａ以上に加圧することで、ファインバブルをガラスに内在させることが可能であることが示された。そして、例１～３のガラスは、肉眼で観察した際に気泡が視認されず、良好な外観性を有していた。 As apparent from Table 1, in Examples 1 to 3, the glass melt was pressurized by the increase in vapor pressure accompanying the temperature increase in the quartz sealed tube, and the fine density was obtained with a foam density of 2.5 × 10 4 pieces / mm 2 or more. A glass with bubbles was obtained. Moreover, from these results, it was shown that fine bubbles can be contained in glass by pressurizing the glass melt to 3 MPa or more regardless of the glass system. In the glasses of Examples 1 to 3, no bubbles were visually recognized when observed with the naked eye, and the glass had good appearance.
　一方で、例４は常圧溶解であり、５００ｒｐｍの回転速度で撹拌して気液混合させても、泡密度は小さく、また気泡径も大きいものしか得られなかった。そして、例４のガラスは、肉眼で観察した際に気泡が視認され、外観性に劣るものであった。
　なお、例５においては、板状のガラスサンプルのＳＥＭ観察では気泡は観察されなかった。 On the other hand, Example 4 was atmospheric pressure dissolution, and even when stirring and gas-liquid mixing at a rotational speed of 500 rpm, only bubbles having a small bubble density and a large bubble diameter were obtained. And when the glass of Example 4 was observed with the naked eye, bubbles were visually recognized and the appearance was inferior.
In Example 5, bubbles were not observed by SEM observation of the plate-like glass sample.
　表１より明らかなように、気泡径が小さく、泡密度が大きくなるに従って、熱伝導率が低くなることがわかった。特に、ガラス組成が同じである例３のガラスと例４のガラスを比較すると、例３のガラスの熱伝導率（０．６２Ｗ／ｍ・Ｋ）は例４のガラスの熱伝導率（０．７２Ｗ／ｍ・Ｋ）に対して有意に低いものであった。また、ガラス組成が同じである例３のガラスと例５のガラスを比較すると、気泡が観察されなかった例５のガラスの熱伝導率（０．７１Ｗ／ｍ・Ｋ）に対しても、例３のガラスの熱伝導率（０．６２Ｗ／ｍ・Ｋ）は有意に低いものであった。 As is apparent from Table 1, it was found that the thermal conductivity decreases as the bubble diameter decreases and the bubble density increases. In particular, when the glass of Example 3 and the glass of Example 4 having the same glass composition are compared, the thermal conductivity (0.62 W / m · K) of the glass of Example 3 is the thermal conductivity (0. 72 W / m · K). Further, when the glass of Example 3 and the glass of Example 5 having the same glass composition are compared, the thermal conductivity (0.71 W / m · K) of the glass of Example 5 in which bubbles were not observed is also an example. The thermal conductivity (0.62 W / m · K) of the glass No. 3 was significantly low.
　例６および７のガラスについて、加工、研磨して得られた外径８ｍｍ、厚さ１ｍｍのサンプルを絶対ＰＬ量子収率測定装置（浜松ホトニクス社製、商品名：Ｑｕａｎｔａｕｒｕ－ＱＹ）を使用して、励起光波長３８０ｎｍにて量子変換収率を測定した。その結果を表２に示す。 For the glasses of Examples 6 and 7, a sample having an outer diameter of 8 mm and a thickness of 1 mm obtained by processing and polishing was used using an absolute PL quantum yield measurement apparatus (manufactured by Hamamatsu Photonics, trade name: Quantauru-QY). The quantum conversion yield was measured at an excitation light wavelength of 380 nm. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２より明らかなように、２．５×１０４個／ｍｍ２以上の泡密度でファインバブルを内在した例６のガラスは、例７のガラスと比較して大きな量子変換収率を示し、蛍光ガラスとしても特性向上に寄与することが確認できた。 As is clear from Table 2, the glass of Example 6 in which fine bubbles were contained at a bubble density of 2.5 × 10 4 pieces / mm 2 or more showed a large quantum conversion yield as compared with the glass of Example 7, It was confirmed that the fluorescent glass contributes to the improvement of characteristics.
　また、ソーダライムガラス、アルミノシリケートガラス、ボロシリケートガラス、リン酸ガラス、フツリン酸ガラス、ハライドガラス、カルコゲナイトガラス等において、上記実施例同様に、本発明のファインバブルガラスが得られる。 Further, in the case of soda lime glass, aluminosilicate glass, borosilicate glass, phosphate glass, fluorophosphate glass, halide glass, chalcogenite glass, etc., the fine bubble glass of the present invention is obtained in the same manner as in the above examples.
　本発明を特定の態様を参照して詳細に説明したが、本発明の精神と範囲を離れることなく様々な変更および修正が可能であることは、当業者にとって明らかである。
　なお、本出願は、２０１５年１２月２４日付けで出願された日本特許出願（特願２０１５－２５１３６７）に基づいており、その全体が引用により援用される。 Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
Note that this application is based on a Japanese patent application filed on December 24, 2015 (Japanese Patent Application No. 2015-251367), which is incorporated by reference in its entirety.
　本発明のガラスは、気泡を含有しながらも、任意の方向からの外観性が良好である。
　また、本発明のガラスは、前記気泡の気泡径、アスペクト比及び個数を適宜調整することにより、軽量性、断熱性、遮音性、電気的絶縁性、熱電効果、光散乱制御性等の種々の特性を発現しうる。したがって、光学素子、電気的素子、熱電変換素子、音響素子、軽量断熱材等の種々の用途への応用が期待される。 The glass of the present invention has good appearance from any direction while containing bubbles.
In addition, the glass of the present invention has various properties such as lightness, heat insulation, sound insulation, electrical insulation, thermoelectric effect, light scattering controllability, etc. by appropriately adjusting the bubble diameter, aspect ratio and number of the bubbles. It can develop properties. Therefore, the application to various uses, such as an optical element, an electrical element, a thermoelectric conversion element, an acoustic element, and a lightweight heat insulating material, is expected.

Claims (7)

  1. 　気泡を含有するガラスであって、
    　前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が１．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が５０μｍ以下であり、アスペクト比が１．２５以下であるガラス。     A glass containing bubbles,
    When the cross section of the glass is observed, the number of the bubbles in the cross section is 1.0 × 10 2 / mm 2 or more, the bubble diameter of the bubbles is 50 μm or less, and the aspect ratio is 1. Glass that is 25 or less.
  2. 　前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が２．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が２０μｍ以下である請求項１に記載のガラス。 The number of the bubbles in the cross section when the cross section of the glass is observed is 2.0 × 10 2 / mm 2 or more, and the bubble diameter of the bubbles is 20 μm or less. Glass.
  3. 　前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が５．０×１０４個／ｍｍ２以上であり、かつ、前記気泡の気泡径が５００ｎｍ以下である請求項１または２に記載のガラス。 The number of the bubbles in the cross section when the cross section of the glass is observed is 5.0 × 10 4 pieces / mm 2 or more, and the bubble diameter of the bubbles is 500 nm or less. The glass described.
  4. 　前記ガラスの断面を観察したときの、前記断面における前記気泡の個数が１．０×１０２個／ｍｍ２以上であり、かつ、前記気泡の気泡径が１５μｍ以下であり、アスペクト比が１．２以下である請求項１に記載のガラス。 When the cross section of the glass is observed, the number of bubbles in the cross section is 1.0 × 10 2 / mm 2 or more, the bubble diameter of the bubbles is 15 μm or less, and the aspect ratio is 1. The glass according to claim 1, which is 2 or less.
  5. 　０．２～１００ＭＰａに加圧しながらガラスを溶解させる溶解工程、溶解された前記ガラスを冷却する冷却工程、及び、冷却された前記ガラスを徐冷する徐冷工程を備えるガラスの製造方法。 A method for producing glass comprising a melting step of melting glass while applying a pressure of 0.2 to 100 MPa, a cooling step of cooling the melted glass, and a slow cooling step of slowly cooling the cooled glass.
  6. 　請求項１～４のいずれかに記載のガラスを製造する方法であって、
    　０．２～１００ＭＰａに加圧しながらガラスを溶解させる溶解工程、溶解された前記ガラスを冷却する冷却工程、及び、冷却された前記ガラスを徐冷する徐冷工程を備えるガラスの製造方法。     A method for producing the glass according to any one of claims 1 to 4,
    A glass production method comprising: a melting step of melting glass while applying a pressure of 0.2 to 100 MPa; a cooling step of cooling the melted glass; and a slow cooling step of gradually cooling the cooled glass.
  7. 　前記冷却工程における冷却速度が１００℃／ｍｉｎ以上である請求項５または６に記載のガラスの製造方法。 The method for producing glass according to claim 5 or 6, wherein a cooling rate in the cooling step is 100 ° C / min or more.
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US4552577A (en) * 1983-04-05 1985-11-12 Pedro B. Macedo Method of producing shaped foamed-glass articles
JPH08143329A (en) * 1993-10-08 1996-06-04 Tosoh Corp High purity opaque quartz glass, its production and its use
JPH11209135A (en) * 1998-01-27 1999-08-03 Tosoh Corp Production of opaque quartz glass ring with transparent part
JP2010280523A (en) * 2009-06-03 2010-12-16 Konica Minolta Opto Inc Fluorescent substance-dispersed glass and method for producing the same

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Publication number Priority date Publication date Assignee Title
US4552577A (en) * 1983-04-05 1985-11-12 Pedro B. Macedo Method of producing shaped foamed-glass articles
JPH08143329A (en) * 1993-10-08 1996-06-04 Tosoh Corp High purity opaque quartz glass, its production and its use
JPH11209135A (en) * 1998-01-27 1999-08-03 Tosoh Corp Production of opaque quartz glass ring with transparent part
JP2010280523A (en) * 2009-06-03 2010-12-16 Konica Minolta Opto Inc Fluorescent substance-dispersed glass and method for producing the same

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021172232A1 (en) * 2020-02-28 2021-09-02 Ａｇｃ株式会社 Silica glass, high frequency device using silica glass, and silica glass production method

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