JP2005097030A - Organic inorganic hybrid glass-like material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic inorganic hybrid glass-like material from a raw material used for the sol-gel process as a starting material and its manufacturing method. <P>SOLUTION: This manufacturing method of an organic inorganic hybrid glass-like material comprises a mixing process in which an oxide precursor as a raw material, water, acetic acid, and an alcohol are mixed, followed by a heating reaction process, a melting process, and an ageing process. The oxide precursor is a metal alkoxide of Si, Ti, Al, Ge, Sn, B, P, Pd, In, Zn, Ga, etc. The acetic acid is not less than 0.1 times the oxide precursor by mole ratio, and the water used in the mixing process is not less than 10 times the oxide precursor by mole ratio and not less than 1.0 times the alcohol. The organic inorganic hybrid glass-like material manufactured by this method is also provided. It has an irregular net structure in part or in its integrity and it is transparent and has an average transmissivity for visible light of 85% or more in the range of wavelength of 300-800 nm at a sickness of 5 mm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic-inorganic hybrid glassy material starting from a raw material used in the sol-gel method and a method for producing the same.

  As materials that soften at 600 ° C. or lower, polymer materials and low-melting glass are well known, and have been used in many places such as sealing and sealing materials, passivation glasses, glazes, and the like. Polymer materials and low-melting glass have different physical properties, so they have been used properly according to the environment in which they can be used. In general, glass is used when heat resistance and hermetic performance are prioritized, and organic materials represented by polymer materials are used in fields where properties other than heat resistance and hermetic performance are prioritized. However, along with recent technological progress, attention has been paid to properties that have not been required so far, and development of materials having such properties is expected.

For this reason, the development of polymer materials with increased heat resistance and airtight performance and so-called low-melting glass, which is a glass with a softened region lowered in temperature, has been actively carried out. Especially in the electronic materials market where heat resistance and airtightness are required, low melting point glass such as PbO-SiO ₂ -B ₂ O ₃ or PbO-P ₂ O ₅ -SnF ₂ It is an indispensable material in fields such as sealing and coating. In addition, the low melting point glass can reduce the energy required for the molding process and the cost compared to the high temperature molten glass, and therefore, it meets the recent social demand for energy saving. Furthermore, if it can be melted at a temperature that does not destroy the organic substance having optical functional performance, it can be expected to be applied to an optical information communication device such as an optical switch as a host of the optical functional organic substance-containing (nonlinear) optical material. As described above, materials having heat resistance and airtightness, which are the characteristics of general molten glass, and easily obtaining various properties such as polymer materials are demanded in many fields. Expectations are gathered. Furthermore, organic-inorganic hybrid glass is also attracting attention as one of low-melting glass.

  As the low melting point glass, for example, Tick glass represented by Sn-Pb-PFO glass (for example, see Non-Patent Document 1) is famous, and has a glass transition point around 100 ° C., and is excellent. It has been used in some markets due to its water resistance. However, since this low melting point glass contains lead as a main component, it is necessary to replace it with an alternative material from the recent trend of environmental protection. Furthermore, the required characteristics for Tick glass have changed greatly, and at the same time the demands have diversified.

  As a general glass production method, a melting method and a low-temperature synthesis method are known. The melting method is a method in which a glass raw material is directly heated to be melted and vitrified. Many glasses are produced by this method, and low-melting glass is also produced by this method. However, in the case of a low-melting glass, there are many restrictions on the glass composition that can be constructed, such as the need to contain lead, alkali, bismuth, etc. in order to lower the melting point.

  On the other hand, as a low-temperature synthesis method of amorphous bulk, a sol-gel method, a liquid phase reaction method, and an acid anhydride base reaction method are considered. In the sol-gel method, a bulk body can be obtained by hydrolysis-polycondensation of metal alkoxide and the like, and heat treatment at a temperature exceeding 500 ° C. (for example, see Non-Patent Document 2), usually 700 to 1600 ° C. However, when a bulk material produced by the sol-gel method is viewed as a practical material, it is porous due to the decomposition and combustion of organic substances such as alcohol introduced during the preparation of the raw material solution, or evaporative emission in the process of heating organic decomposition gas or water. In many cases, there were problems in heat resistance and airtightness. As described above, many problems still remain in bulk production by the sol-gel method, and in particular, low-melting glass has not been produced by the sol-gel method.

  In addition, the liquid phase reaction method has a low yield, resulting in low productivity, the use of hydrofluoric acid in the reaction system and the limited synthesis of thin films. It is almost impossible to synthesize.

  The anhydride-base reaction method is a technique developed in recent years, and it is possible to produce an organic-inorganic hybrid glass that is one of low-melting glasses (for example, see Non-Patent Document 3), but it is still under development. Not all low-melting glasses can be made.

  Therefore, many low-melting-point glasses have been manufactured not by a low-temperature synthesis method but by a melting method. For this reason, the glass composition is limited for the convenience of melting the glass raw material, and the kind of the low melting glass that can be produced is extremely limited.

  At present, low-melting glass is a promising material due to heat resistance and airtightness, and required physical properties are often obtained in a form typified by low-melting glass. However, the material is not particular about the low melting point glass, and if the required physical properties match, there is no major problem with a low melting point or low softening point substance other than glass.

As for known techniques, a method for producing quartz glass fibers by the sol-gel method (for example, see Patent Document 1), a method for producing titanium oxide fibers by the sol-gel method (for example, see Patent Document 2), and further a semiconductor by the sol-gel method. A method for manufacturing a dope matrix (see, for example, Patent Document 3) is known. Further, P ₂ O ₅ —TeO ₂ —ZnF ₂ -based low-melting glass by a melting method is known (for example, see Patent Document 4).
JP-A-62-297236 JP-A-62-223323 Japanese Unexamined Patent Publication No. 1-183438 Japanese Patent Laid-Open No. 7-126035 PATick, Physics and Chemistry of Glasses, 14, 1140 (1989). Kamiya, K., Sakuhana, K., Tashiro, K., Ceramic Society, 618-618, 84 (1976). Masahide Takahashi, Haruki Niida, Toshinobu Yokoo, New Glass, 8-14, 17 (2002).

  Many low softening point materials, particularly low melting glass, have been manufactured by melting methods. For this reason, the glass composition has many restrictions, and the low melting glass which can be produced was very limited on account of melting a glass raw material.

  On the other hand, when manufactured by the sol-gel method of the low temperature synthesis method, a processing temperature of 500 ° C. or higher is required for densification, but if it is processed at that temperature, it does not become a low melting point glass, resulting in heat resistance and airtight performance. No good low melting point glass could be obtained. In particular, in the field of electronic materials, there has been no low-melting glass corresponding to severe heat resistance, airtight performance and low melting point. Furthermore, no low-melting-point material other than glass that satisfies heat resistance and hermetic performance has been found so far.

  The methods disclosed in JP-A-62-297236, JP-A-62-223323, and JP-A-1-183438 made it possible to produce materials at low temperatures that could only be handled by high-temperature melting. Although there is an achievement, low melting glass cannot be manufactured. Further, after sol-gel treatment, treatment at 500 ° C. or higher is also necessary. On the other hand, the method disclosed in Japanese Patent Application Laid-Open No. 7-126035 discloses that a glass having a transition point of 3 and several tens of degrees Celsius can be produced. However, there has been no example of manufacturing a glass having a transition point lower than that without a low melting point material such as lead or bismuth.

  In other words, conventional low-melting glass manufacturing methods have not been able to produce a glass that satisfies severe heat resistance, airtightness and low-melting characteristics at the same time. In addition, no material other than glass satisfies such characteristics.

  Furthermore, the present inventors have developed an organic-inorganic hybrid glassy material that solves the above-mentioned problems and filed a patent application (Japanese Patent Application No. 2003-69327). However, it is the same to produce an organic-inorganic hybrid glassy material using a material used in the sol-gel method as a starting material, but a process of passing through a gel body after the mixing process of the starting material is indispensable. There was a problem of requiring about 3 days. There was also a problem that a slight yellow coloration was observed.

  In the case of producing an organic-inorganic hybrid glassy material, the present invention is an organic material produced through a heating reaction step, a melting step, and an aging step after a mixing step using raw material oxide precursor, water, acetic acid and alcohol. It is a manufacturing method of an inorganic hybrid glassy substance.

  The oxide precursor is a method for producing an organic-inorganic hybrid glassy material which is an alkoxide such as Si, Ti, Al, Ge, Sn, B, P, Pd, In, Zn, and Ga.

  Moreover, acetic acid is a manufacturing method of the organic-inorganic hybrid glassy substance which is 0.1 times or more of an oxide precursor by molar ratio, and the water used at a mixing process is 10 times or more of an oxide precursor by molar ratio. .

  Further, the water used in the mixing step is a method for producing the above organic-inorganic hybrid glassy substance in which the molar ratio is 1.0 times or more that of alcohol.

  Moreover, a heating reaction process is a manufacturing method of said organic-inorganic hybrid glassy substance performed at the temperature of 40 to 100 degreeC.

  The melting step is a method for producing the organic-inorganic hybrid glassy substance performed at a temperature of 40 ° C. or higher and 500 ° C. or lower.

  Moreover, it is a manufacturing method of said organic inorganic hybrid glassy substance processed at the temperature of 30 degreeC or more and 400 degrees C or less in an aging process.

  Further, it is an organic-inorganic hybrid glassy material produced by the above method.

  Furthermore, the organic-inorganic hybrid glassy material described above having an irregular network structure in part or all of the glassy material.

  Furthermore, the organic-inorganic hybrid glassy material is colorless and transparent.

  Furthermore, it is an organic-inorganic hybrid glassy material having a high visible light transmittance as described above, wherein the average visible light transmittance at a wavelength of 300 to 800 nm is 5 mm and is 85% or more.

  According to the present invention, an organic-inorganic hybrid glassy material that satisfies the heat resistance, hermetic performance and low melting point characteristics, which have been considered extremely difficult to produce, can be produced at the same time, and is colorless and transparent with high transmittance.

  In the case of producing an organic-inorganic hybrid glassy material, the present invention undergoes a heating reaction step, a melting step, and an aging step after a mixing step using an oxide precursor, water, acetic acid, and alcohol as a glassy material raw material. It is a manufacturing method of the organic-inorganic hybrid glassy material manufactured. In the present invention, in addition to a new concept of melting a product obtained from an oxide precursor that is generally used as a raw material for the sol-gel method, a gelation process that requires 1 to 3 days can be eliminated. It also has the feature that an organic-inorganic hybrid glassy material that is colorless and transparent and has high visible light transmittance can be produced. In addition, a desired organic-inorganic hybrid glassy substance can be obtained by using acetic acid as a catalyst and passing through the above-mentioned mixing step, melting step, and aging step.

  The starting material is an oxide precursor. The oxide precursor is preferably an alkoxide such as Si, Ti, Al, Ge, Sn, B, P, Pd, In, Zn, or Ga, particularly a metal alkoxide. However, any metal acetylacetonate, metal carboxylate, metal nitrate, metal hydroxide, metal halide, or the like used in the sol-gel method can be produced.

  Conventionally, hydrochloric acid and nitric acid are often used as catalysts in the sol-gel method. This was because the gel time was longer with other catalysts. However, it is also important to use acetic acid in the mixing step of the present invention. By mixing acetic acid and a large amount of water simultaneously, the absorptance in the visible light region can be extremely reduced. That is, an extremely high transmittance glassy material can be obtained. This effect is obtained for the first time by mixing acetic acid and water.

  The amount of acetic acid is preferably at least 0.1 times that of the oxide precursor in a molar ratio, and the water used in the mixing step is preferably at least 10 times that of the oxide precursor in the molar ratio. This is because the amounts of acetic acid and oxide precursors, as well as the amount of water used in the mixing step with acetic acid, have a great influence on the properties of the organic-inorganic hybrid glassy material of the final product. If the amount of acetic acid is less than 0.1 times that of the oxide precursor, the resulting glass has a low mechanical strength. Moreover, when the amount of water used in the mixing step is less than 10 times that of the oxide precursor, there is a problem that the mechanical strength of the obtained glass is low.

  Moreover, it is preferable that the water used at a mixing process is 1.0 times or more of alcohol by molar ratio. In the conventional sol-gel method, although it depends on the type of alcohol, water is the minimum necessary for hydrolysis. This arises from the basic problem of suppressing rapid hydrolysis and the formation of unstable sols. In the case of forming a thin sol-gel film, a large amount of water is sometimes used, but in the case of a bulk form, the amount is as small as possible, for example, about 0.3 times that of alcohol is a conventional method. However, in the present invention characterized by having an aging step, if the water used in the mixing step is less than 1.0 times the alcohol, there is a problem that the aging step takes a lot of time. However, even if the amount of water is too much, a long time is required for the aging step, and therefore, the amount is more preferably 1.0 times or more and 5.0 times or less that of alcohol. In the mixing step, water, ethanol, and acetic acid as a catalyst are added to the oxide precursor and mixed with stirring, but this order is not particular.

  Typical alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 1.1-dimethyl-1-ethanol and the like. However, it is not limited to these.

It is preferable to have a heating reaction step before entering the melting step, that is, between the starting material mixing step and the melting step by heating. This heating reaction step is performed at a temperature of 40 ° C. or higher and 100 ° C. or lower. Outside this temperature range, a metal unit having an organic functional group R in its structure, for example, a silicon unit represented by (R _n SiO _{(4-n) / 2} ) (selected from n = 1, 2, 3), Further, in detail, a phenyl group metal unit (Ph _n SiO _{(4-n) / 2} ), a methyl group silicon unit (Me _n SiO _{(4-n) / 2} ), an ethyl group silicon unit (Et _n SiO _{(4-n) / 2} ), butyl group silicon units (Bt _n SiO _{(4-n) / 2} ) (n = 1 to 3) and the like cannot be appropriately contained, so that glass-melting organic Obtaining an inorganic hybrid glassy material becomes extremely difficult. The organic functional group R is typically an alkyl group or an aryl group. The alkyl group may be linear, branched or cyclic. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group (n-, i-), a butyl group (n-, i-, t-), a pentyl group, a hexyl group (carbon number: 1 to 20). Particularly preferred are methyl and ethyl groups. Furthermore, examples of the aryl group include a phenyl group, a pyridyl group, a tolyl group, and a xylyl group, and a phenyl group is particularly preferable. Of course, the organic functional group is not limited to the above-described alkyl group or aryl group.

  The upper limit temperature of the heating reaction step is 100 ° C. or lower when an alcohol having a boiling point exceeding 100 ° C., for example, 1-butanol having a boiling point of 118 ° C. is used, but it is desirable to consider the boiling point of alcohol having a boiling point of 100 ° C. or lower. For example, when ethanol is used, the boiling point tends to be better at 80 ° C. or lower. This is presumably because when the boiling point is exceeded, the alcohol rapidly evaporates, so that it is difficult to achieve a uniform reaction from the amount of alcohol and changes in state.

  Since the time required for this heat treatment is about 30 minutes to 5 hours, it is greatly different from the treatment time by the conventional sol-gel method, which takes 1 to 3 days for gelation. In addition, after this heating reaction process, you may enter into a melting process immediately, and may enter into a melting process after cooling once.

  The melting step by heating is performed at a temperature of 40 ° C. or more and 500 ° C. or less. At temperatures lower than 40 ° C., it cannot be melted substantially. Further, when the temperature exceeds 500 ° C., the organic group bonded to the metal element forming the network burns, so that a desired organic-inorganic hybrid glassy material cannot be obtained, and it becomes opaque due to crushing or generation of bubbles. Or Desirably, it is 100 degreeC or more and 300 degrees C or less.

  A stable organic-inorganic hybrid glassy material can be obtained through the melting step and the aging step. In the conventional sol-gel method, since there is no melting step, there is naturally no subsequent aging step. Moreover, in this invention which does not go through a gel body, an organic-inorganic hybrid glassy substance can be obtained by a melting process. However, a more stable organic-inorganic hybrid glassy material can be obtained through a subsequent aging step.

  In the aging step, the treatment is performed at a temperature of 30 ° C. or higher and 400 ° C. or lower. At a temperature lower than 30 ° C., it cannot be aged substantially. When it exceeds 400 ° C., it may be thermally decomposed, and it becomes difficult to obtain a stable glassy substance. Desirably, it is 100 degreeC or more and 300 degrees C or less. Further, the effect of the aging temperature becomes extremely small at a temperature lower than the lower limit melting temperature. Generally, the lower limit of melting temperature to the lower limit of melting temperature (+ 150 ° C.) is desirable. Furthermore, the time required for aging is 5 minutes or more. The aging time varies depending on the processing amount, processing temperature, and allowable residual amount of reactive hydroxyl group (—OH), but generally it is extremely difficult to reach a satisfactory level in less than 5 minutes. Moreover, since productivity falls in a long time, it is 10 minutes or more and less than 1 week desirably.

  In addition, in the melting step or the aging step by heating, the time tends to be shortened by performing it under an inert atmosphere or under pressure or reduced pressure. Microwave heating is also effective. Furthermore, the heating reaction step, the melting step, and the aging step may be performed continuously.

  Of course, all the organic-inorganic hybrid glassy materials produced by the above-mentioned method are targets, but some or all of them are organic-inorganic hybrid glassy materials having an irregular network structure.

  The organic-inorganic hybrid glassy material is characterized by being colorless and transparent. In general, an organic-inorganic hybrid glassy substance often has a pale yellow coloration, but a colorless and transparent organic-inorganic hybrid glassy substance can be obtained.

  Furthermore, it is an organic-inorganic hybrid glassy material having a high visible light transmittance with an average visible light transmittance of 5 mm thickness and 85% or more at a wavelength of 300 to 800 nm. By the above-described method, an organic-inorganic hybrid glassy material having an average visible light transmittance of 5 mm in thickness and a wavelength of 300 to 800 nm of 85% or more is targeted.

Hereinafter, description will be made based on examples.
(Example 1)
A metal alkoxide phenyltriethoxysilane (PhSi (OEt) ₃ ) was used as a starting material. As a mixing step, about 45 ml of water (molar ratio to phenyltriethoxysilane is about 50), about 20 ml of ethanol (molar ratio to phenyltriethoxysilane is about 10), 10% phenyltriethoxysilane at room temperature, and acetic acid as a catalyst. About 0.30 ml (molar ratio to phenyltriethoxysilane is about 0.1) and mixed with stirring. After heating for 3 hours with stirring at 60 ° C. as a heating reaction step, the temperature is raised to 150 ° C. over 2 hours. Melted. Furthermore, after aging at 150 ° C. for 3 hours, the mixture was cooled to room temperature to obtain a flaky transparent material having a thickness of 1.7 mm.

  The softening temperature of this transparent material was 130 ° C., which was lower than the decomposition temperature of the phenyl group of about 400 ° C. Further, considering that it has an irregular network structure, the transparent material obtained this time is a material having an organic-inorganic hybrid glass structure, that is, an organic-inorganic hybrid glassy material.

  In order to check the airtight performance of the organic-inorganic hybrid glassy material, an organic dye was put into the obtained organic-inorganic hybrid glassy material, and the bleeding state after one month was observed. As a result, no oozing was observed and it was found that the airtight performance was satisfied. Further, the transition point of this organic-inorganic hybrid glassy substance placed in an atmosphere of 100 ° C. for 300 hours was measured, but no change was observed, and it was confirmed that there was no problem in heat resistance. Furthermore, although the obtained organic-inorganic hybrid glassy substance was left in the atmosphere for one month, no particular change was observed, and it was confirmed that it was excellent in chemical durability.

  Furthermore, as shown in FIG. 1, the transmittance curve in each wavelength range of the organic-inorganic hybrid glassy substance was measured using a Hitachi U-3500 type self-recording spectrophotometer. The solid line data written as Example 1 corresponds to this. As is apparent from this result, it can be seen that there is no large coloration, particularly absorption in the blue region which has been conventionally observed. The average visible light transmittance at a wavelength of 300 to 800 nm was 85.4%.

(Example 2)
The starting material was metal alkoxide ethyltriethoxysilane (EtSi (OEt) ₃ ). As a mixing step, 11 ml of ethyltriethoxysilane (EtSi (OEt) ₃ ) and about 45 ml of water (molar ratio to ethyltriethoxysilane is about 50) and 20 ml of ethanol (molar ratio to ethyltriethoxysilane are about 10 at room temperature). ), Adding about 0.30 ml of acetic acid as a catalyst (molar ratio to ethyltriethoxysilane is about 0.1), mixing with stirring, heating at 50 ° C. for 3 hours with stirring as a heating reaction step, and then to room temperature Cooled down. Then, it melted in an atmosphere at 150 ° C. Further, after aging at 200 ° C. for 5 hours, the mixture was cooled to room temperature to obtain a flaky transparent material having a thickness of 1.7 mm.

  Considering that the softening temperature of this glass material is 180 ° C. and having an irregular network structure, the transparent material obtained this time is a material having an organic-inorganic hybrid glass structure, that is, an organic-inorganic hybrid glassy material. It is. In order to check the airtight performance of the organic-inorganic hybrid glassy material, an organic dye was put into the obtained organic-inorganic hybrid glassy material, and the bleeding state after one month was observed. As a result, no oozing was observed and it was found that the airtight performance was satisfied. Further, the transition point of this organic-inorganic hybrid glassy substance placed in an atmosphere of 100 ° C. for 300 hours was measured, but no change was observed, and it was confirmed that there was no problem in heat resistance. Furthermore, although the obtained organic-inorganic hybrid glassy substance was left in the atmosphere for one month, no particular change was observed, and it was confirmed that it was excellent in chemical durability.

(Comparative Example 1)
A metal alkoxide phenyltriethoxysilane (PhSi (OEt) ₃ ) was used as a starting material. As a mixing step, about 10 ml of phenyltriethoxysilane at room temperature, about 3 ml of water (molar ratio to phenyltriethoxysilane is about 3), about 20 ml of ethanol (molar ratio to phenyltriethoxysilane is about 10), catalyst. About 0.04 ml of hydrochloric acid (molar ratio to phenyltriethoxysilane is about 0.01) is added and mixed with stirring. After heating for 3 hours at 80 ° C. with stirring as a heating reaction step, the temperature is raised to 150 ° C. for 1 hour 30 Partial melting gave a pale yellow glassy material. Furthermore, after aging at 160 ° C. for 5 hours and cooling to room temperature, the glassy substance remained pale yellow. The plate thickness was about 1.7 mm.

  Furthermore, as shown in FIG. 1, the transmittance curve in each wavelength range of the organic-inorganic hybrid glassy substance was measured using a Hitachi U-3500 type self-recording spectrophotometer. The broken line data written as Comparative Example 1 corresponds to this. As is clear from this result, the average transmittance of visible light at a wavelength of 300 to 800 nm was about 45.4%, and the visible light transmittance showed a low value.

The transmittance | permeability measurement result shown in Example 1 and Comparative Example 1 of this invention.

Claims (11)

In the case of producing an organic-inorganic hybrid glassy material, it is produced through a heating reaction process, a melting process and an aging process after a mixing process using an oxide precursor, water, acetic acid and alcohol as raw materials. A method for producing an inorganic hybrid glassy material. 2. The organic-inorganic hybrid glassy material according to claim 1, wherein the oxide precursor is an alkoxide of Si, Ti, Al, Ge, Sn, B, P, Pd, In, Zn, Ga, or the like. Production method. The acetic acid is 0.1 times or more of the oxide precursor in a molar ratio, and the water used in the mixing step is 10 times or more of the oxide precursor in a molar ratio. The manufacturing method of the organic-inorganic hybrid glassy substance of description. The method for producing an organic-inorganic hybrid glassy material according to any one of claims 1 to 3, wherein water used in the mixing step is 1.0 times or more of alcohol in a molar ratio. The method for producing an organic-inorganic hybrid glassy material according to any one of claims 1 to 4, wherein the heating reaction step is performed at a temperature of 40 ° C to 100 ° C. The method for producing an organic-inorganic hybrid glassy material according to any one of claims 1 to 5, wherein the melting step is performed at a temperature of 40 ° C or higher and 500 ° C or lower. The method for producing an organic-inorganic hybrid glassy material according to any one of claims 1 to 6, wherein the aging step is performed at a temperature of 30 ° C to 400 ° C. An organic-inorganic hybrid glassy material produced by the method according to claim 1. The organic-inorganic hybrid glassy material according to claim 8, wherein a part or all of the glassy material has an irregular network structure. The organic-inorganic hybrid glassy material according to claim 8 or 9, which is colorless and transparent. The organic-inorganic hybrid glassy material having a high visible light transmittance according to any one of claims 8 to 10, wherein an average transmittance of visible light at a wavelength of 300 to 800 nm is 85 mm or more at a thickness of 5 mm.

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