JP6826445B2 - Potassium hexafluoride and manganese-activated compound fluoride phosphor using it - Google Patents

Description

The present invention relates to potassium hexafluoride and a method for producing the same, and an active difluoride phosphor with manganese using the potassium hexafluoride as a raw material and a method for producing the same.

In recent years, a white light emitting diode (white LED), which is a combination of a light emitting diode (LED) and a phosphor, has been widely used as a backlight source for a liquid crystal display. Fluorescent materials used for liquid crystal backlights are required to have high color purity in order to reproduce a wide range of colors on the chromaticity coordinates, and they emit sharp light in consideration of compatibility with color filters. A phosphor having a spectrum is desired.

In general, a phosphor has a structure in which a substance controlling light emission (also referred to as a light emitting center or an activator) is further dissolved in a parent crystal (also referred to as a mother crystal or a host crystal). It is also called activation to give a fluorescence function by dissolving the light emitting center in the matrix crystal.

Examples of the emission center of the phosphor having a sharp red emission spectrum include Eu ³⁺ and Mn ⁴⁺ . When Mn ⁴⁺ is dissolved in a parent crystal of a compound fluoride, for example, a mother crystal of potassium silicate represented by K ₂ SiF ₆ in the general formula (composition formula) and activated, the general formula is K ₂ A typical active manganese-activated difluoride phosphor represented by SiF ₆ : Mn ⁴⁺ can be obtained. Since this phosphor is efficiently excited by blue light and has a sharp red emission spectrum with a narrow half width, its application to white LEDs is being actively promoted.

As a method for producing an active difluoride phosphor with manganese represented by K ₂ SiF ₆ : Mn ⁴⁺ , elements constituting the phosphor are dissolved in an aqueous hydrofluoric acid solution, and two or more different types of the above-mentioned fluorides are prepared. A method of precipitating a phosphor by mixing an aqueous hydrofluoric acid solution or reacting the aqueous hydrofluoric acid solution with a solid raw material (Patent Document 1), or fluorescence in an aqueous hydrofluoric acid solution containing an element constituting the phosphor. There is a method (Patent Document 2) in which a poor solvent of the body is added to precipitate the aqueous solution.
In these methods, as a raw material as a source of manganese manganese Tsukekatsufuku fluoride phosphor, to produce a MnF ₆ ^2-dissolved in aqueous hydrofluoric acid, the general formula of K ₂ MnF ₆ Potassium hexafluoride manganate is used. As a method for producing potassium hexafluoromanganate, a Bode method (Non-Patent Document 1) and an electrolytic precipitation method (Patent Document 3 and Non-Patent Document 2) are known.

Japanese Patent No. 4582259 U.S. Pat. No. 3,576,756 Japanese Patent No. 5845999

H. Bode, H. Jenssen, and F. Bandte, Angew. Chem. , 1953, 304. Published by Maruzen Co., Ltd., edited by The Chemical Society of Japan, New Experimental Chemistry Course 8 "Synthesis of Inorganic Compounds III", published in 1977, p. 1166

K 2 _{SiF 6:} Mn Tsukekatsufuku fluoride phosphors typified by Mn ⁴⁺ not only fluorescent properties, even further improvements in reliability of thermal stability and moisture resistance such as phosphor sought There is.
The present invention, fluorescent properties and can be used as a raw material for the production of highly reliable manganese Tsukekatsufuku fluoride phosphors, the general formula six potassium fluoride manganate and a manufacturing method thereof represented by K ₂ MnF ₆ It is an object of the present invention to provide an active difluoride phosphor with manganese obtained by using the potassium hexafluoride as a raw material and a method for producing the same.

As a result of diligent studies, the present inventors focused on the manganese raw material that is the source of Mn ⁴⁺ , that is, potassium hexafluoride, which is the emission center of the active difluoride phosphor with manganese. Synthesized using potassium hexafluoride, which has a diffraction peak at a specific position different from the powder X-ray diffraction pattern conventionally known as potassium hexafluoride, as one of the raw materials. It was found that the fluorescence characteristics and reliability of the obtained active manganese-activated difluoride phosphor were improved.

That is, the present inventors investigated the relationship between the powder X-ray diffraction pattern of potassium permanganate used as a raw material and the fluorescence characteristics and reliability of the obtained active difluoride phosphor with manganese. However, the powder X-ray diffraction pattern of potassium permanganate in which a phosphor exhibiting good properties is obtained is different from the known potassium permanganate registered in ICSD (The Organic Crystal Structure Database). It has been found to show different powder X-ray diffraction patterns.
The present inventors have also found that potassium permanganate showing the powder X-ray diffraction pattern can be obtained under specific production conditions.

That is, the potassium permanganate according to the present invention has a diffraction angle of 2θ of 18.2 ± 0.3 ° and 19.2 ± 0.3 in the powder X-ray diffraction pattern measured using CuKα rays. The gist is to have diffraction peaks at positions at °, 26.6 ± 0.3 °, 31.8 ± 0.3 °, and 42.0 ± 0.3 °. This potassium hexafluoride is preferably used as a raw material for an active difluoride phosphor with manganese. The active difluoride phosphor with manganese is preferably a potassium silicate phosphor.
Further, the method for producing potassium hexafluoride according to the present invention is a step of dissolving potassium hexafluoride in an aqueous solution of hydrofluoric acid having a concentration of 50% by mass or more to prepare an aqueous solution A, an aqueous solution containing potassium. The gist includes a step of preparing B and a step of mixing the aqueous solution A and the aqueous solution B at a temperature of 5 ° C. or lower to reprecipitate potassium hexafluoride.
Further, it is a gist that the active difluoride phosphor with manganese according to the present invention was obtained by using the potassium hexafluoride as a raw material. The active difluoride phosphor with manganese is preferably a potassium silicate phosphor.
Furthermore, the gist of the method for producing an active difluoride phosphor with manganese according to the present invention is to use the potassium hexafluoride as a raw material.

In the present invention, the powder X-ray diffraction pattern has the same meaning as the powder X-ray diffraction spectrum and the powder X-ray diffraction chart, and generally, the word "powder" is omitted and simply "X-ray diffraction" is used. Sometimes called a "pattern".
Further, the active difluoride phosphor with manganese has, for example, tetravalent manganese ion (sometimes referred to as Mn ⁴⁺ ) at the center of light emission, and the general formula is represented by A ₂ MF ₆ : Mn ⁴⁺ , which is an element. A is an alkali metal element containing at least K, element M is one or more metal elements selected from Si, Ge, Sn, Ti, Zr and Hf, and element F is a general term for phosphors which are fluorine. ..
In addition, in this specification, when it is simply described as "manganese" in katakana, it means manganese in general without specifying a valence.

By using the potassium hexafluoride manganese of the present invention as a raw material for an active difluoride phosphor with manganese, manganese is added, which has high fluorescence characteristics and excellent reliability of the phosphor such as thermal stability and moisture resistance. An active compound fluoride phosphor can be obtained.

In comparison with the powder X-ray diffraction pattern of potassium permanganate of Example 1 and the powder X-ray diffraction pattern of potassium permanganate registered in ICSD-76273 (Japan Association for International Chemical Information). is there. In comparison with the powder X-ray diffraction pattern of potassium permanganate of Comparative Example 1 and the powder X-ray diffraction pattern of potassium permanganate registered in ICSD-76273 (Japan Association for International Chemical Information). is there.

<Potassium hexafluoride manganate>
Potassium permanganate according to the present invention has a diffraction peak (that is, a value of diffraction angle 2θ) at a specific position in a powder X-ray diffraction pattern, and is preferably used as a raw material for a manganese-activated active difluoride phosphor. .. Note hexapotassium fluoride manganate of the present invention is preferably a state of generating MnF ₆ ^2-complex ions dissolved in aqueous solution of hydrofluoric acid, the general formula (formula) is in the K ₂ MnF ₆ It is a compound represented.

In general, when identifying an unknown inorganic compound, in addition to chemical analysis for specifying the elemental composition constituting the inorganic compound, the powder X-ray diffraction pattern of the inorganic compound is combined with the powder X-ray diffraction pattern previously stored in the database. A method of examining both of the comparison results of the crystal structures compared and collated is used. If the elemental composition is expected, it is possible to only measure the powder X-ray diffraction pattern and collate with existing data.

Regarding the elemental composition of potassium permanganate of the present invention, manganese and potassium can be quantitatively analyzed by applying a generally known ICP-MS method, atomic absorption method, or the like. Further, fluorine can be analyzed by an ion chromatograph method. And together these analysis results, it is possible compositional formula confirms that satisfy K ₂ MnF _6.

Further, the powder X-ray diffraction pattern of potassium permanganate of the present invention does not require a special device, and uses a generally commercially available X-ray diffraction measuring device by a commonly known measuring method. Obtainable. That is, using a commercially available powder X-ray diffraction measuring device, CuKα rays (1.5406 Å), which are single-wavelength X-rays, are filled in the sample table of the device and irradiated to the set powder sample while changing the angle. Then, by measuring the value of the diffraction angle 2θ and the diffraction intensity of the X-ray reflected by the sample, an X-ray diffraction pattern relating to the sample can be obtained. Whether or not the powder sample is potassium permanganate can be confirmed by comparing and collating with the database information of the X-ray diffraction pattern (for example, ICSD-76273, Japan Association for International Chemical Information). However, hexapotassium fluoride manganate of the present invention, also the general formula from the results obtained by chemical analysis (composition formula) is a one represented by K ₂ MnF _6, the powder X-ray diffraction pattern , The information on the conventionally known potassium hexafluoride shown in ICSD-76273 does not always match, and the diffraction angle 2θ in the powder X-ray diffraction pattern is 18.2 ± 0.3 °, 19. Diffraction peaks are shown at positions of .2 ± 0.3 °, 26.6 ± 0.3 °, 31.8 ± 0.3 °, and 42.0 ± 0.3 °. Further, the potassium hexafluoride manganese of the present invention shows a diffraction peak at a position of 43.1 ± 0.3 ° and does not show a diffraction peak at a position of 20.4 ± 0.3 °. It can also differ from the conventionally known potassium hexafluoride manganate in that respect.

It should be noted that the reason why the allowable width, that is, the width of ± 0.3 ° is provided in the value of the diffraction angle 2θ is that the diffraction angle 2θ is slightly deviated from the ideal value due to a slight distortion of the crystal lattice or the like. Because there are times. In the present invention, the object of the present invention can be achieved if this deviation is within ± 0.3 °. Further, the potassium hexafluoromanganate of the present invention tends to be in the form of plate-shaped particles, and when the powder sample is filled in the sample table, the specific surfaces of the crystals are easily aligned, and even if the sample is the same, the powder The intensity of each diffraction peak tends to fluctuate depending on how the sample is filled during the X-ray diffraction measurement. Therefore, the intensity of the diffraction peak of the present invention is not limited, and the diffraction angle 2θ may satisfy the provisions of the present invention.

Further, the potassium hexafluoride manganate of the present invention is defined in the present invention in its powder X-ray diffraction pattern as long as it does not interfere with the purpose of improving the fluorescence characteristics and reliability of the active difluoride phosphor with manganese. The diffraction peak may be provided at a position other than the diffraction angle 2θ. That is, the potassium hexafluoride manganese of the present invention does not necessarily have to be single-phase or pure, and the manganese hexafluoride of the present invention does not interfere with the object of the present invention. It may contain a crystal phase different from that of potassium, other compounds, or impurities. Specifically, even if a known potassium hexafluoride manganese whose powder X-ray diffraction pattern matches that of ICSD-76273 and other manganese sources containing the constituent elements of the active difluoride phosphor with manganese are mixed. good. Of course, the more potassium permanganate having the powder X-ray diffraction pattern specified in the present invention is contained, the higher the effect is preferable. Therefore, the ratio of potassium hexafluoride having the above-mentioned predetermined diffraction peak to the total potassium hexafluoride as a raw material is preferably 20 wt% or more, more preferably 50 wt% or more.

<Manufacturing method of potassium hexafluoride manganate>
The preferred embodiment of the production method for obtaining potassium hexafluoride manganate of the present invention is shown below. However, the potassium hexafluoride manganese of the present invention is not limited to that obtained by the method described below, and the diffraction angle 2θ of the diffraction peak in the powder X-ray diffraction pattern satisfies the above condition. If this is the case, a conventionally known method or a method in which they are appropriately combined may be used.

A preferred method for producing potassium hexafluoride of the present invention is an aqueous hydrofluoric acid solution (hereinafter referred to as solution A) in which potassium hexafluoride is dissolved, which is not particularly limited in terms of powder X-ray diffraction pattern. A compound serving as a potassium source, for example, an aqueous solution in which potassium hydrogenfluoride is dissolved (hereinafter referred to as solution B) is prepared, and then solution A and solution B are mixed to obtain saturated solubility in the mixed solution. This is a method for reprecipitating the excess potassium hexafluoride. According to the study by the present inventors, the ratio of hydrogen fluoride in the solution A is increased as much as possible, and the temperature of the mixed solution when the solution A and the solution B are mixed to reprecipitate potassium permanganate is set. By lowering the value as much as possible, the potassium permanganate of the present invention having the above-mentioned predetermined diffraction peak can be obtained. Specifically, the ratio of hydrogen fluoride in the solution A is preferably 50% by mass or more, more preferably 60% by mass or more. The temperature of the mixed solution at the time of reprecipitation is preferably 5 ° C. or lower, more preferably 0 ° C. or lower.

<Active compound fluoride phosphor with manganese>
The active difluoride phosphor with manganese according to the present invention is a phosphor obtained by using the above-mentioned potassium hexafluoride as a raw material, and has fluorescent characteristics and fluorescence characteristics as compared with the conventional active difluoride phosphor with manganese. It has excellent reliability.

The fluorescence characteristics of a phosphor are evaluated by the values of the absorption rate of the phosphor, the internal quantum efficiency, and the external quantum efficiency, which can be measured by a commercially available device. The higher the respective values, the better the fluorescence characteristics and the higher the fluorescence intensity, and it can be said that the phosphor is preferable. Since the fluorescence characteristics are affected by the particle size of the phosphors, it is necessary to make the particle sizes of the phosphors uniform before evaluating the fluorescence characteristics.

The reliability of the phosphor is a heat and moisture resistance property evaluated in an actual usage mode. Specifically, a curable resin in which a phosphor is dispersed is directly potted on a blue LED light emitter, cured to produce a packaged test LED element, and the LED element is continuously emitted under high temperature and high humidity. It is a value evaluated from the brightness change (retention rate of the total luminous flux) of the fluorescence before and after the application.

The parent crystal of the active compound fluoride phosphor with manganese according to the present invention is efficiently excited by blue light, exhibits high color purity red emission at a wavelength of around 630 nm, and is relatively moisture resistant among fluorides. , hexapotassium fluoride silicate represented by the general formula K ₂ SiF ₆ excellent in thermal stability are preferred. Whether the fluorophore is an active potassium silicate phosphor with manganese is whether its powder X-ray diffraction pattern matches the known potassium silicate pattern of potassium silicate hexafluoride, and , It can be confirmed by examining whether or not fluorescence is emitted by irradiation with blue excitation light.
Since the fluorescence characteristics of an active potassium silicate phosphor with manganese are affected by the size of its particle size, the median diameter (d50) on a volume basis is usually within the range of 0.1 to 100 μm. It is preferably in the range of 5 to 50 μm, and more preferably in the range of 5 to 50 μm.

<Manufacturing method of active compound fluoride phosphor with manganese>
The method for producing an active difluoride phosphor with manganese according to the present invention uses the above-mentioned potassium hexafluoride as a raw material. By using the above-mentioned specific potassium hexafluoride, an active difluoride phosphor with manganese having excellent fluorescence characteristics and reliability can be synthesized.

Examples of the method for producing an active potassium silicate silicate with manganese include (a) to (c) below on the premise that at least potassium permanganate according to the present invention is used as a raw material. be able to.
(B) Prepare two or more hydrofluoric acid aqueous solutions in which one or more elements of potassium, silicon and manganese are dissolved, mix these aqueous solutions, and activate manganese-activated silica hexafluoride having a saturated solubility or higher. A method for precipitating a potassium silicate phosphor, which mainly uses the potassium hexafluoride manganate of the present invention as a manganese source;
(B) A method of adding a poor solvent such as alcohol, acetone, or water to an aqueous hydrofluoric acid solution in which potassium, silicon, and manganese are dissolved to precipitate active potassium hexafluoride silicate with manganese (poor solvent). Method), which mainly uses the potassium hexafluoride manganate of the present invention as a manganese source;
(C) Silicon dioxide is added to a hydrofluoric acid aqueous solution in which potassium and manganese are dissolved, or silicon dioxide and a manganese compound are added to a hydrofluoric acid aqueous solution in which potassium is dissolved, and the dissolution of silicon dioxide powder proceeds. A method for precipitating a potassium hexafluoride silicate phosphor in parallel with the above method, wherein the potassium hexafluoride manganate of the present invention is mainly used as a manganese source.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention.

<Comparative example 1>
Potassium hexafluoride (referred to as raw material C) of Comparative Example 1 was synthesized according to the Bode method described in Non-Patent Document 1. That is, 800 ml of hydrofluoric acid having a concentration of 40% by mass was placed in a fluororesin beaker having a capacity of 2000 ml, 260 g of potassium bifluoride powder (manufactured by Wako Pure Chemical Industries, Ltd., a special grade reagent), and potassium permanganate powder (Wako Pure Chemical Industries, Ltd.). 12 g (manufactured by Yakuhin Kogyo, first-class reagent) was dissolved. While stirring this hydrofluoric acid solution, 8 ml of 30% hydrogen peroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) was added dropwise little by little. When the amount of hydrogen peroxide solution added exceeded a certain amount, yellow powder considered to be potassium permanganate began to precipitate, and the color of the reaction solution began to change from purple. After dropping 8 ml of hydrogen peroxide solution, stirring was continued for a while, and then the stirring was stopped to precipitate the precipitated powder. The precipitation reaction was carried out at 25 ± 2 ° C. After the precipitation, the operation of removing the supernatant liquid and adding methanol was repeated until the liquid became neutral. Then, the precipitated powder was recovered by filtration and further dried to completely evaporate and remove methanol to obtain potassium permanganate (raw material C) of Comparative Example 1.

<Example 1>
Potassium hexafluoride (referred to as raw material A) of Example 1 was synthesized according to the following procedure. That is, a fluororesin beaker having a capacity of 2000 ml was set in a constant temperature bath (ethylene glycol aqueous solution) set at −5 ° C., 500 ml of a hydrofluoric acid aqueous solution having a concentration of 50% by mass was placed therein, and manganese hexafluoride of Comparative Example 1 was added. An aqueous solution (referred to as aqueous solution A1) in which 25 g of potassium acid powder was dissolved was prepared. Next, another fluororesin beaker having a capacity of 2000 ml was set in the constant temperature bath set at −5 ° C., 500 ml of hydrofluoric acid having a concentration of 40% by mass was added, and 120 g of potassium bifluoride powder was dissolved. An aqueous solution (referred to as aqueous solution B) was prepared. Further, in the constant temperature bath, the entire amount of the aqueous solution B was gradually added dropwise to the aqueous solution A1 while stirring the aqueous solution A1. When the amount of the aqueous solution B dropped exceeded a certain amount, it was confirmed that the yellow powder, which was considered to be potassium hexafluoride, started to precipitate. After the dropping of the aqueous solution B was completed, the stirring was continued for a while, the stirring was stopped, and the precipitated yellow powder was precipitated. The precipitation reaction was carried out in a range where the temperature of the aqueous solution did not exceed 0 ° C. After the yellow powder was precipitated, the operation of removing the supernatant and adding methanol was repeated until the solution became neutral. Then, the yellow powder precipitated by filtration was recovered, and further dried to completely evaporate and remove methanol to obtain potassium permanganate (raw material A) of Example 1.

<Example 2>
Potassium hexafluoride (referred to as raw material B) of Example 2 was synthesized according to the following procedure. That is, a fluororesin beaker having a capacity of 2000 ml was set in a constant temperature bath (ethylene glycol aqueous solution) set at −5 ° C., 500 ml of a hydrofluoric acid aqueous solution having a concentration of 55% by mass was placed therein, and manganese hexafluoride of Comparative Example 1 was added. An aqueous solution (referred to as aqueous solution A2) in which 225 g of potassium acid powder was dissolved was prepared. After that, the aqueous solution A2 was used instead of the aqueous solution A1 of Example 1 to obtain potassium hexafluoride manganese (raw material B) of Example 2 by the same method as in Example 1.

<Comparative example 2>
The potassium hexafluoride manganate (used as the raw material D) of Comparative Example 2 is an example except that the set temperature of the constant temperature bath is set to 20 ° C and the temperature at the time of the potassium hexafluoride precipitation reaction is set to 20 to 25 ° C. It was synthesized by the same method as in 1.

<Chemical analysis to identify elemental composition>
The elemental compositions of the yellow powders of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were quantitatively analyzed for potassium and manganese by the ICP-MS method, respectively, and the balance was determined as fluorine. Table 1 shows the mass ratios (%) of potassium, manganese, and fluorine for each yellow powder. From these results, the atomic number ratios of potassium, manganese, and fluorine in the yellow powders of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were all approximately 2: 1: 6, and the composition formula was K _2. It was confirmed that it was potassium hexafluoromanganate represented by MnF ₆ .

<Measurement of powder X-ray diffraction pattern of potassium permanganate>
Each powder X-ray diffraction pattern for potassium permanganate of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 is shown below using an X-ray diffractometer (D8 ADVANCE, manufactured by Bruker AXS). Measured under conditions.
Type of tube: CuKα tube Tube voltage: 40 (kV)
Tube current: 40 (mA)
Goniometer scanning angle range: 15 ° to 60 °
Goniometer scanning speed: 0.008 ° / 0.1 sec

Table 2 shows the values of the diffraction angles 2θ of the diffraction peaks appearing on the powder X-ray diffraction patterns for each of the potassium permanganate hexafluoride of Example 1 and Comparative Example 1. In Table 2, only the diffraction peaks having a diffraction intensity of 5% or more of the intensity of the largest diffraction peak are shown. Further, Table 2 also shows known powder X-ray diffraction pattern information of potassium permanganate (value of diffraction angle 2θ described in ICSD-76273), which is generally distributed by the Japan Association for International Chemical Information. It is also described as a reference example.
Further, the powder X-ray diffraction patterns of Example 1 and Comparative Example 1 are used as a control together with the powder X-ray diffraction pattern of potassium permanganate registered in ICSD-76273 (Japan Association for International Chemical Information). And FIG. 2, respectively. Since the result of Example 2 was the same as that of Example 1 and the result of Comparative Example 2 was the same as the result of Comparative Example 1, Example 2 and Comparative Example 2 are not shown.
From this result, the potassium permanganate of Comparative Examples 1 and 2 was almost the same as the known powder X-ray diffraction pattern of potassium permanganate in 2θ, whereas the values of 2θ were almost the same as those of Examples 1 and 2. It was shown that potassium permanganate does not match these patterns, that is, it has a crystal structure different from the conventionally known crystal structure.

* A value that satisfies the diffraction peak specified in the present invention.

<Preparation of phosphor>
Next, each potassium silicate manganese hexafluoride (that is, raw material A, raw material B, raw material C, raw material D) of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was used as a raw material one by one. The active potassium silicate phosphors with manganese of Example 11, Example 12, Comparative Example 11, and Comparative Example 12 were synthesized by the following methods.

<Example 11>
In an environment of 25 ± 2 ° C., put 1000 ml of 55% by mass hydrofluoric acid in a fluororesin beaker with a capacity of 2000 ml and dissolve 127.5 g of potassium bifluoride powder (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.). To prepare an aqueous solution. While stirring this aqueous solution, 34.5 g of powdered silicon dioxide (FB-50R, amorphous type, specific surface area 0.4 m ² / g, manufactured by Denka Co., Ltd.) and powdered hexafluoride of Example 1 4.5 g of potassium manganate (that is, raw material A) was put into the aqueous solution. When the powder is added to the aqueous solution, the temperature of the aqueous solution begins to rise due to the heat of dissolution of silicon dioxide, and at about the same time, a yellow powder thought to be a manganese-activated potassium silicate silicate phosphor begins to form in the aqueous solution. confirmed. The temperature of the aqueous solution reached the maximum temperature (about 40 ° C.) about 3 minutes after the addition of the powder, and then decreased because the dissolution of silicon dioxide was completed. Even after the silicon dioxide was completely dissolved, stirring of the aqueous solution was continued to complete the precipitation of the yellow powder, and then the solution was allowed to stand to precipitate the solid content. After visually confirming the completion of the precipitation, the supernatant is removed, the yellow powder is washed with hydrofluoric acid and methanol having a concentration of 20% by mass, and the yellow powder is further filtered to collect the solid content by filtration and further dry treatment. Remaining methanol was evaporated and removed. After completion of the drying treatment, a nylon sieve having a mesh size of 75 μm was used, and only the yellow powder that had passed through the sieve was classified and recovered to obtain an active potassium silicate silicate phosphor with manganese of Example 11.

As a result of measuring the powder X-ray diffraction pattern of the phosphor of Example 11 under the same measurement conditions as the X-ray diffractometer used in Example 1, it is the same pattern as the conventionally known potassium silicate crystal. Therefore, it was confirmed that the phosphor of Example 11 was an active potassium silicate phosphor with manganese.

Further, the particle size distribution of the active potassium hexafluoride silicate phosphor with manganese of Example 11 was measured by a laser diffraction scattering type particle size distribution measuring device (MicroTrac MT3300EXII, manufactured by Microtrac Bell), and the cumulative particle size obtained was obtained. From the distribution curve, the volume-based median diameter (d50) was obtained. The results are shown in Table 3. Ethanol was used as the measurement solvent, and crushing treatment by ultrasonic irradiation was carried out as a pretreatment for measurement.

<Example 12, Comparative Example 11, Comparative Example 12>
The active potassium silicate silicate phosphor with manganese of Example 12, Comparative Example 11, and Comparative Example 12 was the potassium hexafluoride manganate of Example 1 used in the method for producing the phosphor of Example 11 (raw material A). ) Was replaced with potassium manganate hexafluoride (that is, raw material B, raw material C, raw material D) of Example 2, Comparative Example 1, and Comparative Example 2, respectively, and synthesized by the same method as in Example 11. The powder X-ray diffraction pattern of each phosphor was measured by the same method as in Example 11, and it was confirmed that all the phosphors were active potassium silicate silicate phosphors with manganese. Further, the median diameter of each phosphor was also measured by the same method applied to the phosphor of Example 11, and is also shown in Table 3. From these results, the median diameters of the phosphors of Examples 11 and 12 and Comparative Examples 11 and 12 were in the range of 28 to 29 μm and were almost the same, and the fluorescent particles were evaluated in the following fluorescence characteristics. It was confirmed that the influence of the size of was excluded.

<Evaluation of fluorescence characteristics>
With respect to the phosphor of Example 11, the fluorescence characteristics (absorption rate of the phosphor, internal quantum efficiency, external quantum efficiency) when excited with blue light having a wavelength of 455 nm are integrated into a generally known spectrophotometer. It was evaluated using a measurement system equipped with. That is, a standard reflector (Spectralon, manufactured by Labsphere) having a reflectance of 99% is set in an integrating sphere (φ60 mm) set in the side opening (φ10 mm), and the wavelength is changed from the Xe lamp, which is a light emitting source, to a wavelength of 455 nm. The separated monochromatic light was introduced by an optical fiber, and the spectrum of the reflected light from the standard reflector was measured by a spectrophotometer (MCPD-7000, manufactured by Otsuka Electronics Co., Ltd.). In this measurement, the ambient temperature at the time of measurement was 25 ± 2 ° C., and the number of excitation photons (referred to as Qex) was obtained from the spectrum in the wavelength range of 450 to 465 nm. Next, a concave cell filled with the phosphor of Example 11 is set in the opening of the integrating sphere so that the surface becomes smooth, and monochromatic light having a wavelength of 455 nm is irradiated to obtain an excitation reflected light and a fluorescence spectrum. It was measured with a spectrophotometer. From the obtained spectral data, the number of excited reflected light photons (referred to as Qref) and the number of fluorescent photons (referred to as Qem) were obtained. The number of excited reflected light photons is in the same wavelength range as the number of excited light photons, and the number of fluorescent photons is a value obtained in the wavelength range of 465 to 800 nm. From the obtained three types of photon numbers, absorption rate (%) = (Qex-Qref) / Qex × 100, internal quantum efficiency (%) = Qem / (Qex-Qref) × 100, external quantum efficiency (%) = The values of Quant / Qex × 100 were calculated, and the results are shown in Table 3. Further, the values of the absorption rate, the internal quantum efficiency, and the external quantum efficiency were obtained for each of the phosphors of Example 12, Comparative Example 11, and Comparative Example 12 by the same method, and are also shown in Table 3. As shown in Table 3, the phosphors of Examples 11 and 12 have almost the same median diameter as the phosphors of Comparative Examples 11 and 12, but have an absorption rate and an internal quantum. It can be seen that both the efficiency and the external quantum efficiency show high values.

<Reliability evaluation of phosphor>
Further, the practical reliability of the active potassium silicate phosphor with manganese of Example 11 was evaluated by the following method. That is, 70 parts by mass of a silicone resin (KER-2500 manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 30 parts by mass of the active potassium silicate silicate phosphor with manganese of Example 11 and kneaded and defoamed to obtain a silicone resin composition. .. Then, the composition was directly potted on a blue LED element having a peak wavelength of 450 nm, and the silicone resin was thermosetting, thereby producing an LED package molded with the silicone resin containing the phosphor of Example 11. .. The total luminous flux value when the obtained LED package was energized and emitted in an environment of 25 ± 2 ° C. was measured by a total luminous flux measuring device (combination of a 300 mm diameter integrating hemisphere and a spectrophotometer / MCPD-9800, Otsuka Electronics). Measured by the company). The same measurement was carried out for five LED packages manufactured in the same manner, and the average of them was used as a representative value of the total luminous flux value. Next, the five LED packages are subjected to a constant temperature and humidity chamber (SH-642,) having a temperature of 85 ° C. and a relative humidity of 85% in accordance with the test method described in JEITA ED-4701 / 100A of the Japan Electronics and Information Technology Industries Association standard. It was lit continuously for 1000 hours in (manufactured by ESPEC). After the end of continuous lighting, the total luminous flux of each LED package is measured again, and the retention rate of the total luminous flux, that is, (representative value of total luminous flux after the end of continuous lighting) / (representative value of total luminous flux before the start of continuous lighting). × 100 (%) was calculated. The retention rate of the total luminous flux value in the LED package using the active potassium silicate phosphorylate with manganese of Example 11 was 90%. The results are shown in Table 3.

The reliability of each of the phosphors of Example 12, Comparative Example 11, and Comparative Example 12 was also evaluated by the same method as in Example 11. That is, the reliability of the phosphors blended in the silicone resin composition that is directly potted on the blue LED element is the same except that the phosphors of Example 12, Comparative Example 11, and Comparative Example 12 are replaced. Was evaluated. This result is also shown in Table 3. From the results in Table 3, the retention rate of the LED package using the fluorescent material of the example is clearly higher than that of the fluorescent material of the comparative example, and the reliability of the fluorescent material such as thermal stability and moisture resistance is high. Was confirmed.

Claims (7)

In the powder X-ray diffraction pattern measured using CuKα rays, the diffraction angles 2θ are 18.2 ± 0.3 °, 19.2 ± 0.3 °, 26.6 ± 0.3 °, 31.8. Potassium hexafluoromanganate having diffraction peaks at positions ± 0.3 ° and 42.0 ± 0.3 ° (however, the height of the strongest peak in the range where 2θ is 17 ° or more and 20 ° or less) When the ratio (In / Imax) of the peak height In in the region n to the Imax is the peak intensity ratio Irn, those whose peak intensity ratio Irn satisfies the following are excluded.
Region 1 20 ° ≤ 2θ ≤ 22 °
Region 2 38 ° ≤ 2θ ≤ 40 °
Region 3 40 ° ≤ 2θ ≤ 42 °
Region 4 46 ° ≤ 2θ ≤ 48 °
Ir1 ≤ 0.3
Ir2 ≧ 0.4
Ir3 ≤ 0.5
Ir4 ≤ 0.1) . The potassium hexafluoride manganese according to claim 1, which is used as a raw material for an active difluoride phosphor with manganese. The potassium permanganate according to claim 2, wherein the active difluoride phosphor with manganese is a potassium silicate phosphor. A step of preparing an aqueous solution A by dissolving potassium hexafluoride in an aqueous solution of hydrofluoric acid having a concentration of 50% by mass or more.
A step of preparing an aqueous solution B containing potassium, and a step of mixing the aqueous solution A and the aqueous solution B at a temperature of 5 ° C. or lower to reprecipitate potassium hexafluoromanganate.
The method for producing potassium hexafluoromanganate according to any one of claims 1 to 3, which comprises. An active difluoride phosphor with manganese obtained by using the potassium hexafluoride manganese according to any one of claims 1 to 3 as a raw material. The active difluoride phosphor with manganese according to claim 5, which is a potassium silicate fluorophore. A method for producing an active difluoride phosphor with manganese, which uses the potassium hexafluoride manganese according to any one of claims 1 to 3 as a raw material.