JPH10226786A - Calcium carbonate fluorescent substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost Sn solid solution calcium carbonate fluorescent substance having a calcitic structure having good luminescent characteristics from inexpensive materials by crystallizing an aqueous solution reaction product containing a soluble calcium slat, carbonic acid (salt) and a soluble tin salt. SOLUTION: An aqueous solution of a soluble tin salt is added to an aqueous solution of a soluble calcium salt, and the resulting solution is mixed with a soluble carbonate, or an aqueous solution of a soluble tin salt is added to an aqueous solution of a soluble calcium salt, and carbon dioxide gas is blown into the resulting solution. The obtained mixture is reacted at 0-50 deg.C. The gel- like substance formed as a result of the reaction is crystallize by heating to 50-90 deg.C in the reaction solution to obtain an Sn-solid solution calcium carbonate phosphor having a calcitic structure and having a degree of substitution with dissolved Sn<2+> (Sn/CaCO3 ) in the range: 0.03mol%<Sn/CaCO3 <=0.06mol%. The fluorescent substance is low-cost and can find its utility in expansive article such as existing color televisions, three-color lamps and cathode-ray tubes and general-purpose articles such as illuminative decorations of buildings, display panels for emergency refuge, traffic markings and other uses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor and a composition containing the same, and more particularly, to a blue and blue-white phosphor which can be produced inexpensively and efficiently and can be widely used for various uses. And a phosphor composition containing the same.

[0002]

2. Description of the Related Art Conventionally, phosphors have been frequently used in fluorescent lamps, color televisions (CTV), three-color lamps, cathode ray tubes (CRT), and the like. And an activator such as a rare earth element or a transition element. As an example, in the case of a blue phosphor, strontium orthophosphate and magnesium phosphor activated with copper, and a calcium halophosphate phosphor activated with antimony are known as typical examples. Recently, attention has been paid to a phosphor in which two kinds of activators are substituted into a base material to form a solid solution to improve luminous efficiency.
Japanese Patent No. 112791 describes a phosphor in which cerium or terbinium is further substituted and solid-solved in an alkaline earth metal salt activated with eurobium.

[0003]

By the way, generally known phosphors need to be treated at a high temperature in order to displace the activator in the structure of the base material and to form a solid solution. For example, if the base material is a ZnS-based material, The calcination is carried out at a high temperature of 800 to 900 ° C. and at a temperature of 1000 to 1250 ° C. for oxysulfide and calcium phosphate. The above-mentioned Japanese Patent Application Laid-Open No. 54-11279
The phosphor described in No. 1 is no exception.
A mixture of Eu ₂ O ₃ and Tb ₄ O ₇ or CeO ₂ was added at 1100 ° C. to 1
It is manufactured by firing at a high temperature of 300 ° C. As described above, the conventional phosphor has to incorporate a high-temperature treatment into its manufacturing process, and as a result, there is a problem that productivity is lowered and manufacturing cost is increased.

It is known that the luminous efficiency of the phosphor depends on the type and purity of the activator. However, most of the phosphors generally known include high purity and expensive rare earth oxides as the activator. You are using

[0005] As described above, the conventional phosphor requires high-temperature treatment, so that the production cost is high, and the raw material costs such as activator are also high, so that the total cost must be high. It is not an exaggeration to say that this has narrowed the versatility of the phosphor.

As an invention for the purpose of cost reduction, a fluorescent material having a light emitting property by using inexpensive calcium carbonate as a base material and coating the surface with a light emitting substance is disclosed in Japanese Patent Application Laid-Open No. 8-504871. It is described in the gazette. In this publication, the use of a chelate solution of a rare-earth element and a transition element as a luminescent substance makes it possible to add light-emitting properties with a small amount of an activator and to reduce the price of a phosphor.

However, since an expensive organic solvent is used for the chelating solution to be applied, it is considered that a drastic reduction in the raw material cost cannot be expected. In addition, if the amount of the luminescent substance coating on the surface of the base material is large, concentration quenching may be caused, so that advanced technology for adjusting the coating amount is required, and the cost associated with this is increased. It is considered difficult to dramatically reduce the manufacturing cost of the phosphor. Further, it is necessary to perform a treatment at a high temperature in order to activate the coated rare earth element, and the disadvantage that the energy cost is high like the conventional phosphor is not improved.

Accordingly, at present, the phosphor is used only for high-priced products such as a color television, a trichromatic lamp, and a cathode ray tube.

However, if an inexpensive phosphor can be manufactured, its versatility is widened. For example, a luminous decoration of a building, an emergency evacuation display panel such as a tunnel or a basement,
Various applications such as traffic safety signs, ceilings, floors, and other general house exteriors are conceivable.

Accordingly, an object of the present invention is to provide a phosphor which can be produced from inexpensive raw materials and which has a low production cost, and a phosphor composition containing the same.

[0011]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies and as a result, have found that an inexpensive aqueous reaction product of a soluble calcium salt, a carbonate (salt) and a soluble tin salt can be obtained.
The present inventors have found that by crystallizing at a low temperature of 90 ° C. or less, a Sn-dissolved calcium carbonate phosphor having a calcite (calcite) type structure having good emission characteristics can be obtained at low cost, and completed the present invention.

That is, the present invention provides a Sn-dissolved calcium carbonate-based phosphor characterized by having a calcite-type structure.

Further, the present invention provides a method for producing a gel-like substance produced by an aqueous solution reaction of (A) a soluble calcium salt, (B) a soluble carbonate or carbon dioxide, and (C) a soluble tin salt in a reaction solution. It is intended to provide the above-mentioned calcium carbonate-based phosphor obtained by conversion.

Further, the present invention provides a phosphor composition containing the above-mentioned calcium carbonate phosphor.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The phosphor of the present invention is Sn²⁺Solid solution
Calcium carbonate phosphor that has a crystallographic structure
The structure must be calcite type. Because kalsa
The light type is Sn ²⁺Since the coordination number is equivalent to²⁺Is the base material
It is easily displaced and solid-solved in the structure of
Type, aragonite type)
It is. For example, FIG. 1 shows a book at an excitation wavelength of 285 nm.
The fluorescence characteristics (light emission) of the calcium carbonate phosphor of the invention
It is shown. From this table, the calcite-type structure
It is clear that the fluorescence characteristics are higher than those of the transformation.

The phosphor of the present invention can be synthesized by pulverizing and mixing calcium carbonate and a tin salt compound, which are base materials, and firing at a high temperature in the same manner as in the conventional method for producing a phosphor. For this purpose, it is preferable to produce by the following method.

That is, (A) a soluble calcium salt,
A method is preferred in which a gel-like substance is generated by an aqueous solution reaction of (B) a soluble carbonate or carbon dioxide gas and (C) a soluble tin salt, and then the gel-like substance is heated and crystallized in a reaction solution.

Examples of the soluble calcium salt used here include halides of calcium, inorganic acid salts of calcium, organic acid salts of calcium, and the like. More specifically, calcium chloride, calcium bromide, calcium iodide and the like can be used. , Calcium nitrate, and anhydrous or hydrated calcium acetate. Note that there is no particular problem as long as the concentration of these aqueous solutions is not more than a saturated solution.

Examples of the soluble carbonate include ammonium carbonate, alkali metal carbonate, ammonium bicarbonate and alkali metal bicarbonate. More specifically, ammonium carbonate, potassium carbonate, sodium carbonate and ammonium hydrogen carbonate , Potassium bicarbonate, sodium bicarbonate, anhydrous sodium potassium carbonate or hydrates thereof. As in the case of the soluble calcium salt, the concentration of these aqueous solutions can be appropriately selected at a concentration of a saturated solution or less. Is good.

As a carbon dioxide source, carbon dioxide gas can be used, but any commercially available carbon dioxide gas can be used without any problem.

As the soluble tin salt, any soluble tin salt compound can be used, and examples thereof include stannous halide and stannous inorganic acid. Examples include stannous, stannous bromide, stannous fluoride, stannous sulfate and the like. The concentration of the aqueous solution of the soluble tin salt has an effect on the solid solution amount and crystallization of the calcium carbonate phosphor of the present invention, and therefore, it is preferable to appropriately set the concentration in accordance with the desired properties of the phosphor.

That is, in the phosphor of the present invention, Sn ²⁺
If the substitution solid solution amount is out of the range of 0.03 mol% <Sn / CaCO ₃ ≦ 0.06 mol%, lattice distortion and lattice defects occur, so that the luminous output of the phosphor is reduced and a desired result is obtained. May disappear. For this reason, the substitution solid solution amount of Sn ²⁺ is preferably in the range of 0.03 mol% <Sn / CaCO ₃ ≦ 0.06 mol%, and particularly when it is 0.04 mol%,
The light emission output shows the highest value, and more preferable results are obtained. Therefore, it is desirable to determine the concentration of the soluble tin salt in consideration of this.

In the first aqueous solution reaction, an aqueous solution of a soluble tin salt is added to an aqueous solution of a soluble calcium salt, and then an aqueous solution of a soluble carbonate is mixed. It is performed by blowing. The reaction temperature at this time is preferably in the range of 0 to 50 ° C. since aragonite may be generated if it exceeds 50 ° C. by any of the methods. The gel-like material obtained in this reaction, in which Sn ²⁺ was incorporated into the amorphous calcium carbonate which is known as a precursor of calcium carbonate (referred A morphous C alcium C arbonate = ACC ).

Next, the reaction mixture obtained by the above reaction is heated to crystallize the gel-like substance, whereby the phosphor of the present invention is obtained. The temperature at this time takes into account the acceleration of the crystallization rate,
Desirably, the temperature is 50 to 90 ° C.

As described above, an inexpensive and highly productive phosphor can be provided by producing an intended phosphor by an aqueous solution reaction using calcium carbonate as a base material. For this reason, the phosphor of the present invention can be used for tricolor lamps and cathode ray tubes (CR
T) It can be used not only for color television but also for paper, rubber, paint, construction materials, etc., which have been difficult to use in terms of cost. Specifically, identification blocks for parking lots in apartments, parks, sightseeing spots, etc., road signs, exteriors of general houses such as park roads, bicycle paths, ceilings and walls, evacuation signs in tunnels and underpasses, theaters and movie theaters Use of a passage or the like is conceivable. As described above, since the phosphor of the present invention is overwhelmingly inexpensive in manufacturing cost as compared with conventional phosphors, it can also be used as a new phosphor.

Therefore, the phosphor composition of the present invention comprises the above Sn
It is manufactured by blending a carrier, a base material and the like according to the above-mentioned use with the solid solution calcium carbonate phosphor. For example, usually, carriers and substrates used in the fields of paper, rubber, paint, construction materials, and the like,
That is, it is manufactured by mixing a paper coating material, a pigment, cement, an aggregate, and the like with a Sn-dissolved calcium carbonate-based phosphor.

[0027]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. A method for measuring the properties of the reagent and the phosphor used in the following examples will be described.

(Reagent) ・ Calcium carbonate: Special grade manufactured by Kanto Chemical Co., Ltd. ・ Calcium chloride: Special grade manufactured by Kanto Chemical Co., Ltd. ・ Calcium nitrate tetrahydrate: Special grade manufactured by Kanto Chemical Co., Ltd. ・ Calcium oxide: Kanto Chemical ( Ammonium carbonate: Kanto Chemical Co., Ltd. Special grade ・ Sodium carbonate: Kanto Chemical Co., Ltd. special grade ・ Carbon dioxide: Suzuki Shokan Co., Ltd., purity 99.7% ・ Methanol: Kanto Chemical Co., Ltd. Special grade ・ Stannous chloride: Kanto Chemical Co., Ltd. deer grade 1 ・ Stannous fluoride: Kanto Chemical Co., Ltd. deer grade 1

(Measurement Method) Crystal Structure of Phosphor: Measurement was performed using a 4037A1 X-ray diffractometer manufactured by Rigaku Corporation. -Amount of solid solution of Sn2 ⁺ : The measurement was performed by a diotyl absorption spectrophotometry. Emission intensity of phosphor: Shimadzu RF-150
The measurement was performed using a type 0 spectrofluorometer. Irradiation was performed at an excitation wavelength of 250 to 285 nm and a temperature of 20 ° C.

The calcium carbonate phosphor according to the present invention comprises:
Synthesized according to the following procedure. In addition, the luminous property was judged as ◎ when it was superior to the calcium halophosphate-based phosphor used for fluorescent lamps, as ○ when equivalent, and × when less than that.

Example 1 3.0 g of CaCO ₃ and 0.06 g of SnCl ₂ are each accurately measured and mixed sufficiently uniformly. This mixture is placed in a quartz container and fired in a carbon dioxide gas atmosphere at 900 to 1100 ° C. for 3 to 5 hours. Next, pulverization and mixing were performed, and a reheating treatment was performed under the same firing conditions. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

Example 2 2.0 g of CaCO ₃ powder and 0.2 g of SnCl ₂ powder are accurately measured and mixed uniformly. This mixed raw material was fired under the same conditions as in Example 1. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

Example 3 0.005 M SnCl was added to 1000 cm ^{3 of a} 0.1 M CaCl ₂ aqueous solution.
₍₂ ) The mixed solution to which 9.5 cm ^{3 of the} aqueous solution was added was placed in a thermostat at 20 ° C.
And then add 0.1 M (NH ₄ ) ₂ CO ₃ aqueous solution at the same temperature for 1 hour.
000 cm ^{3 was} added to obtain a gel-like product. Note that the stirring speed at this time was kept constant at 450 rpm. This suspension was kept in a thermostat at 90 ° C. for 2 hours to crystallize a gel-like product. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

EXAMPLE 4 0.005 M SnCl was added to 1000 cm ^{3 of a} 0.1 M CaCl ₂ aqueous solution.
_{2 After} the mixed solution to which 5 cm ^{3 of the} aqueous solution was added was kept at 20 ° C. in a thermostat, 0.1 M (NH ₄ ) ₂ CO ₃ aqueous solution at the same temperature was added in 100 mL.
0 cm ^{3 was} added to obtain a gel product. The stirring speed at this time was kept constant at 350 rpm. This suspension was kept in a thermostat at 50 ° C. for 5 hours to crystallize a gel-like product. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

Example 5 0.1 M Ca (NO ₃ ) ₂ aqueous solution 0.0017 M in 1000 cm ³
The mixed solution to which 14 cm ^{3 of the} SnF ₂ aqueous solution was added was 35
C., and the mixed solution was fed with CO ₂ gas at a flow rate of 50 cm ^3.
To give a gel-like product. The stirring speed at this time was kept constant at 300 rpm. This suspension was kept in a thermostat at 70 ° C. for 4 hours to crystallize a gel product. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

Example 6 0.005 M S in 1000 cm ³ of 0.1 M Ca (NO ₃ ) ₂ aqueous solution
The mixed solution to which 14 cm ^{3 of} nF ₂ aqueous solution was added was heated to 35 ° C. in a thermostat.
After that, CO ₂ gas was blown into the mixed solution at a flow rate of 50 cm ³ to obtain a gel-like product. The stirring speed at this time was kept constant at 300 rpm. This suspension was kept in a thermostat at 90 ° C. for 2 hours to crystallize a gel-like product.
Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

Example 7 A composition obtained by mixing 30 parts by weight of the calcium carbonate-based phosphor of the present invention prepared by the method of Example 4, 30 parts by weight of sand, 40 parts by weight of cement and 25 parts by weight of water was used.
And a surface forming material having a thickness of about 5 mm was formed. On top of this, a composition composed of ordinary concrete was added, and a cement plate having a thickness of about 15 mm was formed. This cement board was applied to the wall of the building corridor.
As a result, light was emitted by the light of the fluorescent lamp, and the brightness of the entire corridor was increased.

Example 8 To 15 parts by weight of a composition comprising 25% of a methyl methacrylate polymer and 75% of methyl methacrylate, 20 parts by weight of the calcium carbonate-based phosphor of the present invention prepared in Example 4 and limestone A composition obtained by mixing 80 parts by weight of crushed stone (average particle size: 1 mm) and N, N-dimethylaniline was poured into a mold, and heat-cured. Two hours later, the mold was released to obtain a luminescent resin concrete having a thickness of 2 cm. An acrylic resin paint was applied to the surface to produce a nameplate. When this nameplate was glued to a concrete gate post,
It emitted light and visibility was improved.

COMPARATIVE EXAMPLE 1 0.005 M SnCl was added to 1000 cm ^{3 of a} 0.1 M CaCl ₂ aqueous solution.
₍₂ ) The mixed solution to which 9.5 cm ^{3 of the} aqueous solution was added was placed in a thermostat at 20 ° C.
And then add 0.1 M (NH ₄ ) ₂ CO ₃ aqueous solution at the same temperature for 1 hour.
000 cm ^{3 was} added to obtain a gel-like product. The stirring speed at this time was kept constant at 350 rpm. This suspension was kept in a thermostat at 20 ° C. for 6 hours to crystallize a gel-like product. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

COMPARATIVE EXAMPLE ₂ 0.005 M SnCl was added to 1000 cm ^{3 of a} 0.1 M CaCl ₂ aqueous solution.
_{2 The} mixed solution to which 11 cm ^{3 of the} aqueous solution was added was kept at 80 ° C. in a constant temperature bath, and then a 0.1 M (NH ₄ ) ₂ CO ₃ aqueous solution at the same temperature was added in 10 mL.
00 cm ^{3 was} added to obtain a gel product. Note that the stirring speed at this time was kept constant at 450 rpm. This suspension was kept at 80 ° C. for 4 hours in a thermostat to crystallize the gel-like product. Table 1 shows the measurement results of the crystal structure, the amount of Sn-substituted solid solution, and the luminescence of the obtained product.

[0041]

[Table 1]

As shown in Table 1, in Examples 1 to 5, it was confirmed that a phosphor having excellent emission characteristics was obtained because the crystal structure was calcite type. On the other hand, in Comparative Examples 1 and 2, it was confirmed that the luminescent properties were low because the crystal structures were the vaterite type and the aragonite type.

[0043]

According to the present invention, there is no need to perform a sintering process at a high temperature of 1000 ° C. or more unlike the conventional phosphor.
Since it can be synthesized by an aqueous solution reaction at a temperature of 100 ° C. or lower, a phosphor with low energy consumption, high productivity and low cost can be provided, which is useful in expanding the versatility of the phosphor. . Furthermore, since the phosphor of the present invention can be obtained by an aqueous solution reaction, it is easy to set up a recycling process, and therefore has high industrial value from the viewpoint of effective use of resources.

[Brief description of the drawings]

FIG. 1 is a diagram showing the fluorescence characteristics of a calcium carbonate phosphor.

Continuing from the front page (72) Inventor Kenta Masuda 2-4-2 Daisaku, Sakura City, Chiba Pref. Inside Building Materials Techno Laboratory (72) Inventor Yasuo Arai 3-1-17 Naka, National City, Tokyo (72) Invention Person: Tsutomu Yasue 1-19-18, Omiya, Sumiya-ku, Tokyo (72) Inventor: Yoshiyuki Kojima 2-11-21-1101

Claims (4)

[Claims] 1. A Sn-dissolved calcium carbonate phosphor having a calcite structure. 2. A gel-like substance produced by an aqueous solution reaction of (A) a soluble calcium salt, (B) a soluble carbonate or carbon dioxide, and (C) a soluble tin salt is obtained by crystallization in a reaction solution. The calcium carbonate phosphor according to claim 1. 3. Sn²⁺Displacement solid solution amount (Sn / CaCO_Three) Is 0.0
3 mol% <Sn / CaCO _Three≦ 0.06 mol%.
Or the calcium carbonate phosphor according to 2. 4. A phosphor composition containing the calcium carbonate phosphor according to claim 1, 2 or 3.