JPH06316418A - Production of photochromic glass - Google Patents

Abstract

PURPOSE:To inexpensively control a composition by drying and sintering a sol solution obtained by hydrolyzing, etc., a specific mixture and heat treating in a gaseous atmosphere of chlorine or the like. CONSTITUTION:The mixture is obtained by mixing a Si alkoxide of one or more kind selected from a group expressed by a formula I (R is 1-5C alkyl, Y is organic group, n is 0-3), an Al trialkoxide expressed by a formula II (R<1> is 1-5C alkyl), a Na alkoxide expressed by a formula III (R<2> is 1-5C alkyl), a boron trialkoxide expressed by a formula IV (F<3> is 1-5C alkyl), a copper dialkoxide expressed by a formula V (R<4> is 1-5C alkyl), an organic solvent, hydrochloric acid or the like, water and a silver carboxylate expressed by a formula VI ((n) is 2-11). Next, the sol solution obtained by hydrolyzing and condensation polymerizing the mixture is dried at 10-80 deg.C and heat treated at 150-800 deg.C to obtain a porous sintered compact. Next, a photochromic glass is produced by heat treating the sintered compact at 100-800 deg.C in the gaseous atmosphere of bromine or the like to grow silver halide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing photochromic glass.

[0002]

2. Description of the Related Art Glasses of photochromic lenses in which the color density changes depending on the brightness of light (for example, darkening when the amount of light increases) are being sold, and the usefulness of this type of photochromic glass is increasing. Conventionally, photochromic glass has been made of silica sand (SiO ₂ ), soda ash (Na ₂ O), alumina (Al ₂ O ₃ ), boric acid (B ₂ ).
O ₃ ) is blended so as to have a predetermined composition, and a mixture of a small amount of silver halide and copper oxide is heated and melted at a high temperature of 1500 ° C. or higher, and the melt is cooled to produce silver and halogen. Has been produced by a method of producing a transparent glass containing as an ion and reheating this glass at 500 to 600 ° C. to precipitate fine particles of silver halide.

However, in this method, since halogen and silver are easily volatilized at the time of melting at a high temperature, it is necessary to add silver halide in advance excessively, and it is difficult to obtain a photochromic glass having a desired glass composition. In addition, there are problems such as an increase in manufacturing cost. To solve this problem, in JP-A-58-190837, water and hydrochloric acid are added to a mixture of alkoxides of silicon, aluminum and sodium, silver halide is further added, and the mixture is stirred and polymerized to increase the viscosity. When the temperature becomes low, it is placed in a container, gelled and shrunk to form a dry gel. Then, this dry gel is heat-treated at about 900 ° C. to obtain transparent glass, which is heated to 550 ° C. and halogenated. A method of growing a silver particle to manufacture a photochromic glass has been proposed.

Further, in Japanese Patent Laid-Open No. 3-50128, a) SiO ₂ fine particles are prepared by mixing and agitating respective alkoxides of Si, Na, Al, B and Cu, water and alcohol to cause a hydrolysis reaction. A step of adding a fixed amount to prepare a sol, b) a step of gelating the sol and then drying at 50 to 100 ° C. to produce a dry gel, c) further heating the dry gel to make it porous. A step of producing a sintered gel, d) a step of immersing the sintered gel in an aqueous solution containing Ag ⁺ , Cl ⁻ ions, diffusing it inside the gel to obtain a desired composition, and then reheating to vitrify, and e ) A method for producing a photochromic glass has been proposed which comprises a step of treating the obtained glass body at 500 to 600 ° C to obtain a photochromic glass.

[0005]

Problems to be Solved by the Invention JP-A-58-1908
In the manufacturing method proposed in Japanese Patent No. 37, the dry gel is
There is a problem that halogen is volatilized in the step of heat treatment at about 0 ° C. and the step of heating at 550 ° C. to grow grains of silver halide, and it is difficult to obtain a photochromic glass having a desired composition.

Further, in the manufacturing method proposed in Japanese Patent Laid-Open No. 3-50128, when Ag ⁺ and Cl ⁻ ions are diffused inside the sintered gel to form a desired composition, Ag ⁺ ions and Cl ⁻ ions are burned. Since it is difficult to control the diffusion into the binding gel, there is a problem that it is difficult to obtain a photochromic glass having a desired composition. An object of the present invention is to solve the above problems, and to provide a method for producing a photochromic glass in which the glass composition can be easily controlled.

[0007]

The silicon alkoxide (a) used in the present invention is at least one selected from the group consisting of the following general formula [I]. Y _n ─Si (OR) _4-n・ ・ ・ [I]

In the silicon alkoxide (a) represented by the general formula [I], in the formula, R represents an alkyl group having 1 to 5 carbon atoms. However, when the carbon number is increased, the stability of the mixture is lowered and the long-term Since the storability deteriorates, the carbon number is limited to 1-5. Examples of R include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-
Examples thereof include a butyl group and a tert-butyl group. Y represents an organic group, and examples thereof include a hydrocarbon group, a glycidoxyalkyl group, and an aminoalkyl group. Examples of the hydrocarbon group include an alkyl group, a substituted alkyl group, an allyl group, a vinyl group, a phenyl group and a naphthyl group. n shows the integer of 0-3.

Examples of the silicon alkoxide represented by the general formula [I] include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, monomethyltrimethoxysilane, monomethyltriethoxysilane, phenyltrimethoxysilane and γ. -Glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmonomethoxysilane, trimethylmonoethoxysilane and the like. The silicon alkoxide (a) may be used alone or in combination of two or more kinds.

The general formula Al (OR ¹ ) used in the present invention
Examples of the aluminum trialkoxide (b) represented by ₃ (wherein R ¹ is an alkyl group having 1 to 5 carbon atoms) include aluminum tributoxide and aluminum triisopropoxide.

The general formula Na (OR ² ) used in the present invention is
Examples of the sodium alkoxide (c) represented by (wherein R ² is an alkyl group having 1 to 5 carbon atoms) include sodium methoxide and sodium ethoxide.

The general formula B (OR ³ ) ₃ used in the present invention
Examples of the boron trialkoxide (d) represented by (wherein R ³ is an alkyl group having 1 to 5 carbon atoms) include boron tributoxide and boron triisopropoxide.

The general formula Cu (OR ⁴ ) used in the present invention
Examples of the copper dialkoxide (e) represented by ₂ (in the formula, R ⁴ is an alkyl group having 1 to 5 carbon atoms) include copper dimethoxide and copper diethoxide.

The general formula Ag (C _n H used in the present invention
_2n-1 O ₂₎ (wherein, n as a silver carboxylate (i) represented by an integer) of 2 to 11, for example, silver acetate and the like.

The organic solvent (f) used in the present invention includes the silicon alkoxide (a), aluminum trialkoxide (b), sodium alkoxide (c),
Boron trialkoxide (d), copper dialkoxide (e), acid (g), water (h) and silver carboxylate (i)
It is not particularly limited as long as it is compatible with, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and butyl alcohol, ketones such as acetone and methyl ethyl ketone, and tetrahydrofuran, and the like. Methyl alcohol, ethyl alcohol and isopropyl alcohol are preferred. These may be used alone or in combination of two or more.

The amount of the organic solvent (f) added is 3 to 10 with respect to 1 mol in total of the alkoxides (a) to (e).
0 mol is preferable, and 5 to 20 mol is more preferable. When the amount of the organic solvent (f) is small, the mixture is difficult to be uniformly mixed to form a heterogeneous solution, and when the amount is large, the solid content concentration of the solution becomes too low.

The water (h) used in the present invention is added for the hydrolysis of the alkoxides (a) to (e),
Acid (g) is added as a catalyst for the hydrolysis. The amount of water (h) added is preferably 1 to 30 mol, and more preferably 3 to 10 mol, based on 1 mol of the total of the alkoxides (a) to (e). When the amount of water (h) decreases, hydrolysis hardly occurs sufficiently, and when the amount of water (h) increases, the compatibility with the solution deteriorates. Acid (g) is 0.0
It is preferably contained in a proportion of 01 to 0.5% by weight.
When the amount of acid is low, the effect as a catalyst cannot be expected. The acid is not particularly limited, and either an inorganic acid or an organic acid can be used, and examples thereof include hydrochloric acid and sulfuric acid.

As the gas containing chlorine, bromine or iodine atom used in the present invention, for example, chlorine gas, hydrogen chloride gas, bromine gas, hydrogen bromide gas, iodine gas, hydrogen iodide gas and the like are used. .

The blending ratio of the mixture used in the present invention is
SiO ₂ 50 to 65 by weight ratio of oxide after vitrification
_{%, Al 2 O 3 5~15%} , Na 2 O1~15%, B 2
O ₃ 15 to 25% and CuO 0.01 to 0.3% are preferable. Further, silver carboxylate is (SiO ₂ +
(Al ₂ O ₃ + Na ₂ O + B ₂ O ₃ + CuO) 100 parts by weight, and Ag is added in an amount of 0.3 to 2.5 parts by weight.

The photochromic glass of the present invention is manufactured according to the following steps (1) to (4). (1) A solution in which a silicon alkoxide (a), an aluminum trialkoxide (b), a sodium alkoxide (c), a boron trialkoxide (d) and a copper dialkoxide (e) are mixed in an organic solvent (f) at a predetermined ratio. , Silver carboxylate (i) was added at a predetermined ratio, and
Water (h) containing an acid (g) is added, and mixed and stirred to accelerate hydrolysis and polycondensation to prepare a uniform sol solution. In addition, in the preparation of this mixture, the addition order of the components (a) to (h) can be arbitrarily changed.

(2) Next, when it is desired to obtain a bulk photochromic glass, the above sol solution is poured into a container having the shape of the desired photochromic glass. When it is desired to obtain a thin-film photochromic glass, it is applied onto a glass substrate having a desired shape. Examples of the coating method for coating on a glass substrate include spin coating, spray coating, roll coating, dip coating, and flow coating. Next, 1 part of the sol solution injected into the above container or the applied sol solution
Dry at 0-80 ° C to make a dry gel. When the drying temperature is high, cracks occur in the gel, and when the drying temperature is low, the solvent cannot be sufficiently removed.

(3) Next, the dried gel is mixed with 150-800.
By heating at ℃, to produce a porous sintered body containing silver ions. When the sintering temperature becomes high, it becomes difficult to obtain a porous gel,
When it becomes low, sufficient sintering cannot be performed.

(4) Next, the porous sintered body is treated with 100 to 80 in a gas containing chlorine, bromine or iodine atoms.
Heat treatment is performed at 0 ° C. to grow silver halide fine particle nuclei to obtain a photochromic glass. When the heat treatment temperature is high, halogen is likely to volatilize, and when it is low, silver halide is less likely to grow.

The production of the photochromic glass of the present invention 2 is carried out by the following (4) after the steps (1) to (3).
And (5).

(4) The porous sintered body is dipped in water or a lower alcohol solution containing chlorine, bromine or iodine ions, and chlorine, bromine or iodine ions are diffused inside the sintered body to produce halogen. Generate silver halide fine particle nuclei. chlorine,
Examples of the solution containing bromine or iodine ions include hydrogen chloride, sodium chloride, hydrogen bromide, sodium bromide,
Examples thereof include an aqueous solution of hydrogen iodide or an alcohol solution.
Examples of the alcohol include methyl alcohol and ethyl alcohol. The concentration of the halogen ion in the solution is not particularly limited, but the total amount of halogen ion in the solution is preferably at least the number of moles of silver carboxylate used in step (1).

(5) The sintered body in which fine particle nuclei are formed is
The silver halide fine grains are grown by heating at 00 to 800 ° C. When this heating temperature is high, the amount of halogen volatilized is large, and when it is low, the growth of silver halide is not sufficiently performed.

[0027]

EXAMPLES Examples of the present invention will be described below.

Example 1 (1) Silicon tetraethoxide 208.2 g (1.00 mol) Aluminum triisopropoxide 20 g (0.10 mol) Sodium ethoxide 11 g (0.16 mol) Boron tributoxide 52 0.9 g (0.23 mol) 0.3 g (0.002 mol) of copper diethoxide was mixed with 500 g (10.9 mol) of ethyl alcohol, and 200 g of water containing 0.36% by weight of hydrochloric acid.
(11.1 mol) was added and mixed and stirred for 1 hour. Then, 1.55 g (0.01 mol) of silver acetate was added to give 24
A sol solution was obtained by mixing and stirring for a period of time. (2) A sol solution whose viscosity has increased due to hydrolysis / polycondensation is placed in a polystyrene container and kept in a thermostat at 60 ° C. for 7 days for gelation to obtain a dry gel having a thickness of 1.5 cm. It was (3) The dried gel was taken out of the polystyrene container and heated to 750 ° C. at a temperature rising rate of 5 ° C./hour to give A.
A transparent porous glass containing g ions was obtained. (4) The porous glass was flowed with chlorine gas 5
It was left in an electric furnace at 50 ° C. for 10 hours to obtain a photochromic glass.

Example 2 (1) A sol solution was obtained in the same manner as in step (1) of Example 1. (2) A quartz plate (30 mm × 10
(0 mm x 1 mm thickness), and pulling speed 800 mm
After dip-coating at 1 / min, place in a constant temperature bath at 60 ° C for 3
It was kept for a day for gelation to obtain a quartz plate coated with a thin film of dry gel. (3) The thin film-coated quartz plate was heated to 600 ° C. at a heating rate of 5 ° C./hour to obtain a transparent porous glass thin film-coated quartz plate containing Ag ions. (4) This porous glass thin film-coated quartz plate was left in an electric furnace at 550 ° C. in which chlorine gas was allowed to flow for 10 hours to obtain a photochromic glass thin film-coated quartz plate. The thickness of this photochromic glass thin film was 1 μm.

Example 3 Steps (1) to (3) In the same manner as steps (1) to (3) of Example 1, a transparent porous glass containing Ag ions was obtained. (4) 3 mol of this porous glass containing Ag ions
/ L NaCl aqueous solution, leave it for 72 hours,
Fine particle nuclei of AgCl were generated. (5) The porous glass in which fine particle nuclei have been formed is taken out from the above aqueous solution, dried at 40 ° C. for 5 hours, and then 550 ° C.
It was left in the electric furnace for 10 hours to obtain a photochromic glass.

Example 4 Steps (1) to (3) In the same manner as steps (1) to (3) of Example 2, a transparent porous glass thin film-coated quartz plate containing Ag ions was obtained. (4) The porous glass thin film-coated quartz plate containing Ag ions was dipped in a 3 mol / L NaCl aqueous solution, and 72
It was left to stand for a while to generate fine particle nuclei of AgCl. (5) The porous glass thin film-coated quartz plate on which fine particle nuclei have been formed is taken out of the above aqueous solution, dried at 40 ° C. for 5 hours, and then left in an electric furnace at 550 ° C. for 10 hours to obtain a photochromic glass thin film-coated quartz plate. Got The thickness of this photochromic glass thin film was 1 μm.

Comparative Example 1 Steps (1) to (3) Steps (1) to (3) of Example 1 except that a sol solution was prepared without adding silver acetate in Step (1) of Example 1.
Transparent porous glass was obtained in the same manner as in (3). (4) This porous glass was immersed in an aqueous solution in which NaCl and AgNO ₃ were dissolved at a concentration of 3 mol / L and left for 72 hours. (5) Next, take out the porous glass from the aqueous solution,
After drying at 40 ° C. for 5 hours, it was placed in an electric furnace and heated to 950 ° C. at a temperature rising rate of 1 ° C./min. Next, the obtained glass was left in an electric furnace at 550 ° C. for 10 hours to grow AgCl fine particles inside the glass to obtain a photochromic glass.

Evaluation The following evaluations were performed using the glass or glass thin film-coated quartz plates obtained in Examples 1 to 4 and Comparative Example 1 as samples. Composition analysis The composition was analyzed with an X-ray microanalyzer, and the results are shown in Table 1. The unit of the numerical values shown in Table 1 is% by weight.
Further, the target composition is a composition targeted for glass design. Evaluation of photochromic characteristics The following method was performed in a dark room. Shut off the light 30
After holding the minute, the sample was irradiated with light of a 150 watt mercury lamp for 60 minutes, and the light transmittance at a wavelength of 400 nm was measured using a visible / ultraviolet spectrophotometer from immediately after the start of irradiation to 60 minutes later. Next, the light was blocked, and the same measurement was performed from immediately after the blocking to 90 minutes after the blocking. The results are shown in FIGS. 1 and 2.

[0034]

[Table 1]

[0035]

The method for producing a photochromic glass of the present invention is as described above, and unlike the conventional high temperature melting method, it can be produced at a low temperature, so that the glass composition can be easily controlled and the silver halide is previously excessive. Since it does not need to be added, the manufacturing cost is low. As in the methods described in JP-A-58-190837 and JP-A-3-50128, the heating is not performed after the halogen is contained in the glass composition, but is performed while the halogen treatment is performed. It is easy to control the glass composition without the risk of volatilization.

The method for producing the photochromic glass of the present invention 2 is as described above, and unlike the conventional high temperature melting method, it can be produced at a low temperature, so that the glass composition can be easily controlled and the silver halide can be excessively added in advance. Since it does not need to be added, the manufacturing cost is low. In the method described in JP-A-58-190837, after the halogen is contained in the glass composition, heating up to 900 ° C. and reheating at 550 ° C. are performed.
Although the heating step is required twice, in the present invention 2, since the heating after the halogen is contained is only required once, the volatilization of the halogen is reduced and therefore the glass composition can be easily controlled.
According to the method described in Japanese Patent Laid-Open No. 3-50128, both Ag ⁺ and Cl ⁻ ions must be diffused from the liquid phase inside the sintered gel. In Invention 2, however, the Ag ⁺ ions are preliminarily added to the glass composition. Since it is contained in the sintered gel and only Cl ⁻ ions need to be diffused into the sintered gel, the glass composition can be easily controlled.

[Brief description of drawings]

FIG. 1 shows the evaluation results of the photochromic properties of the glass or glass thin film-coated quartz plates obtained in Examples 1 and 2.

FIG. 2 is an evaluation result of photochromic properties of the glass or glass thin film-coated quartz plates obtained in Examples 3 and 4 and Comparative Example 1.

Claims (2)

[Claims] (1) (a) At least one silicon alkoxide selected from the group consisting of the following general formula [I]: Y _n --Si (OR) _4-n ... [I] (wherein , R is an alkyl group having 1 to 5 carbon atoms, Y is an organic group,
(n is an integer of 0 to 3) (b) Aluminum trialkoxide represented by the general formula Al (OR ¹ ) ₃ (wherein, R ¹ is an alkyl group having 1 to 5 carbon atoms), (c) General formula Na ( O
R ² ) (wherein R ² is an alkyl group having 1 to 5 carbon atoms), and (d) the general formula B (OR
³ ) ₃ (in the formula, R ³ is an alkyl group having 1 to 5 carbon atoms), a boron trialkoxide, and (e) a general formula Cu (O
R ⁴ ) ₂ (wherein R ⁴ is an alkyl group having 1 to 5 carbon atoms), a dialkoxide of copper, (f) an organic solvent, (g)
Acid, (h) water, and (i) the general formula Ag (C _n H _2n-1 O
₂ ) (in the formula, n is an integer of 2 to 11) a step of producing a sol solution by hydrolyzing and polycondensing a mixture of silver carboxylates, (2) the sol solution at 10 to 80 ° C. A step of drying and producing a dry gel; (3) a step of heating the dry gel at 150 to 800 ° C. to produce a porous sintered body; and (4) a porous sintered body containing chlorine, A method for producing a photochromic glass, comprising a step of growing silver halide by heat-treating at 100 to 800 ° C. in a gas containing bromine or iodine atoms. 2. After the steps (1), (2) and (3) according to claim 1, (4) the porous sintered body is placed in a water or alcohol solution containing chlorine, bromine or iodine ions. The step of immersing in 100 ° C. to generate silver halide fine grain nuclei, and (5) the sintered body in which the fine grain nuclei are generated,
A method for producing a photochromic glass, which comprises the step of growing silver halide fine particles by heating at 0 ° C.