WO2021251451A1 - Barium titanyl oxalate, method for producing same, and method for producing barium titanate - Google Patents

Barium titanyl oxalate, method for producing same, and method for producing barium titanate Download PDF

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WO2021251451A1
WO2021251451A1 PCT/JP2021/022043 JP2021022043W WO2021251451A1 WO 2021251451 A1 WO2021251451 A1 WO 2021251451A1 JP 2021022043 W JP2021022043 W JP 2021022043W WO 2021251451 A1 WO2021251451 A1 WO 2021251451A1
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barium
oxalate
liquid
titanyl oxalate
producing
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PCT/JP2021/022043
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French (fr)
Japanese (ja)
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宏亮 丹野
武久 国枝
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日本化学工業株式会社
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Priority to CN202180042005.9A priority Critical patent/CN115916792A/en
Priority to KR1020227042889A priority patent/KR20230024274A/en
Publication of WO2021251451A1 publication Critical patent/WO2021251451A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C01G23/006—Alkaline earth titanates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/41—Preparation of salts of carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C55/00—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms
    • C07C55/02—Dicarboxylic acids
    • C07C55/06—Oxalic acid
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C55/00—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms
    • C07C55/02—Dicarboxylic acids
    • C07C55/06—Oxalic acid
    • C07C55/07—Salts thereof
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F3/00—Compounds containing elements of Groups 2 or 12 of the Periodic System
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C07F7/28—Titanium compounds

Definitions

  • the present invention relates to barium oxalate titanyl oxalate, which is useful as a raw material for functional ceramics such as dielectrics, piezoelectric materials, optoelectronic materials, semiconductors, and sensors, and a method for producing the same.
  • barium titanate has been produced by a solid phase method, a hydrothermal synthesis method, an alkoxide method, an oxalate method, or the like.
  • the constituent raw material powder and the like are mixed and the mixture is produced by a dry method of heating at a high temperature. Therefore, the obtained powder forms an agglomerate having an irregular shape and has desired characteristics. High temperature firing is required to achieve this.
  • the hydrothermal synthesis method has the advantages of good powder characteristics, but the synthesis process is complicated, the productivity is inferior because an autoclave is used, the price of the produced powder is high, and it is not industrially advantageous.
  • the alkoxide method is difficult to handle as a starting material, is expensive, and is not industrially advantageous.
  • Barium titanate obtained by the oxalate method can be cheaply produced with a uniform composition as compared with the hydrothermal synthesis method and the alkoxide method, and is compared with barium titanate produced by the solid phase method. It is characterized by a uniform composition.
  • a titanium source such as titanium tetrachloride, a barium source such as barium chloride, and oxalic acid are reacted in a solvent such as water to obtain barium titanyl oxalate, and then the barium oxalate is obtained.
  • a method of firing titanyl is common (see, for example, Patent Documents 1 to 3).
  • barium titanyl oxalate obtained in the above patent document produces barium titanate at a firing temperature of 700 ° C. or higher, the degree of crystallization is low at the time of production of barium titanate, but some grains are formed. It is growing.
  • barium oxalate titanyl oxalate is fired at a high temperature, even high crystals become large particles, and there is a problem that the characteristics as a raw material for functional ceramics cannot be satisfied.
  • barium titanate oxalate which can obtain barium titanate having a small particle size and high crystals, and to provide a method for industrially advantageously producing the barium titanate oxalate. It is in.
  • the present invention (1) provides barium oxalate titanyl oxalate, which is characterized in that the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is 600 to 700 ° C. in thermogravimetric analysis. Is.
  • barium titanate having a specific surface area of 15 to 20 m 2 / g and a c / a of 1.030 to 1.0055 by a heating test at 700 ⁇ 10 ° C. in the air for 2 hours. It provides barium titanate oxalate (1), which is characterized by being converted into.
  • the present invention (3) provides the barium titanyl oxalate according to (1) or (2), which is characterized in that the average particle size is 1.0 ⁇ m or less.
  • barium titanyl oxalate is produced by mixing a solution containing oxalic acid (liquid A) and a solution containing a titanium compound and a barium compound (solution B) and reacting them. It is a method for producing barium titanyl oxalate to be produced. First, the liquid A is filled in the reaction vessel, and then the liquid B is mixed with the liquid A while stirring the liquid A in the reaction vessel.
  • the present invention provides a method for producing barium oxalate titanyl oxalate, characterized in that the time from the start to the end of mixing the liquid B with the liquid A is within 10 seconds.
  • the present invention (5) provides the method for producing barium oxalate titanyl oxalate (4), which is characterized in that the solvent of the liquid A is an organic solvent.
  • the solvent of the solution A is methanol, ethanol, propanol, butanol, diethyl ether, 1,3-butylene glycol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol, N, N-.
  • the present invention provides the method for producing barium titanyl oxalate according to (5), which is one or more selected from the group consisting of dimethylformamide and acetone.
  • the present invention (7) provides the method for producing barium oxalate titanyl oxalate (4), which is characterized in that the solvent of the liquid B is water.
  • the present invention (8) is characterized in that the titanium compound in the liquid B is titanium tetrachloride and the barium compound is barium chloride, which is any barium oxalate (4) to (7). It provides a method for producing titanyl.
  • the present invention (9) provides a method for producing barium oxalate titanyl oxalate according to any one of (4) to (8), wherein the mixing temperature of the liquid B with the liquid A is 40 ° C. or lower. It is something to do.
  • the present invention (10) is characterized in that the average particle size of barium oxalate titanyl produced is 1.0 ⁇ m or less, according to any one of (4) to (9), a method for producing barium oxalate titanyl. It is to provide.
  • the present invention (11) provides a method for producing barium titanate, which comprises calcining barium titanate oxalate obtained by any of the production methods (4) to (10).
  • barium titanate oxalate which can obtain barium titanate having a smaller particle size and higher crystals than conventional barium titanate oxalate when fired at the same temperature. Further, according to the present invention, it is possible to provide a method for industrially advantageously producing the barium titanyl oxalate.
  • the barium oxalate titanyl oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to a weight loss rate of 1000 ° C. at 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685.
  • Barium titanyl oxalate characterized by a temperature of ° C.
  • the weight loss rate of 1000 ° C. in the thermogravimetric analysis refers to the weight loss rate at the time when the analysis temperature in the thermogravimetric analysis is 1000 ° C.
  • the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate of 1000 ° C. in the thermogravimetric analysis means that the weight loss rate at the start of the analysis is 99% of the weight loss rate at the analysis temperature of 1000 ° C. Refers to the temperature at which it reaches.
  • the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is the temperature at which the thermal decomposition of barium titanate oxalate occurs and the conversion to barium titanate ends, that is, barium titanate oxalate.
  • the temperature at which barium titanate is produced from is the temperature at which barium titanate is produced from.
  • the weight loss measured by thermogravimetric analysis of barium titanate oxalate when the temperature of the sample to be measured was raised from room temperature to 10 ° C / min, some weight loss was confirmed, and then at around 700 ° C. It can be confirmed that the weight reduction is no longer confirmed, and finally the barium titanate is thermally decomposed.
  • the weight of the conventional barium titanate oxalate disappears at 700 to 720 ° C., and it can be confirmed that barium titanate is obtained in this temperature range.
  • the barium titanyl oxalate of the present invention cannot be confirmed to lose weight at 600 to 700 ° C, preferably 610 to 690 ° C, particularly preferably 615 to 685 ° C.
  • Barium titanate can be obtained.
  • the average particle size of barium titanyl oxalate obtained by the method for producing barium titanyl oxalate of the present invention, which will be described later is preferably 1.0 ⁇ m or less, particularly preferably 0.01 to 0.5 ⁇ m.
  • the present inventors consider that the fine particles make it easy for carbon dioxide gas to escape during thermal decomposition and change to barium titanate at a lower temperature than in the prior art.
  • the barium titanate oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685.
  • the temperature barium titanate can be produced in the temperature range of 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Therefore, the barium titanate oxalate of the present invention can generate barium titanate at a low temperature, so that barium titanate can be highly crystallized at a lower temperature than before.
  • the barium titanate oxalate of the present invention can crystallize barium titanate at a lower temperature than before, and thus can suppress the grain growth of barium titanate. Barium is obtained. Therefore, according to the barium titanate oxalate of the present invention, finer and higher crystal barium titanate can be obtained as compared with the conventional barium titanate oxalate when fired at the same temperature.
  • the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate of 1000 ° C exceeds 700 ° C the temperature at which barium titanate is produced from barium titanyl oxalate becomes high, so that the temperature for subsequent high crystallization can be achieved. The heating temperature also becomes high, and as a result, the particle size of barium titanate becomes large.
  • thermogravimetric analyzer used for thermogravimetric analysis of barium titanyl oxalate is not particularly limited, and examples thereof include TGA / DSC 1 manufactured by METTLER TOLEDO CO., LTD.
  • the barium titanyl oxalate of the present invention has a specific surface area of 15 to 20 m 2 / g and a c / a of 1.0030 to 1.0055 by a heating test at 700 ⁇ 10 ° C. for 2 hours in the atmosphere. It is preferably barium titanyl oxalate that is converted to.
  • the specific surface area of barium titanate obtained by heating the barium titanyl oxalate of the present invention in the air at 700 ⁇ 10 ° C. for 2 hours is particularly preferably 16 to 19 m 2 / g.
  • the specific surface area of barium titanate produced by the heating test at 700 ⁇ 10 ° C. in the air for 2 hours is in the above range, and c / a is in the above range. Even if grain growth occurs due to heating for crystallization, finer and higher crystal barium titanate can be obtained as compared with the conventional barium titanate oxalate.
  • the heating test of barium titanyl oxalate the measurement target sample was held for 2 hours in a heating device whose temperature was controlled to 700 ⁇ 10 ° C., and the heating test was performed. After cooling, the measurement target sample after the heating test was BET. Specific surface area analysis and X-ray diffraction analysis by the method are performed to determine the specific surface area and c / a of the sample to be measured after the heating test.
  • the average particle size of barium titanyl oxalate of the present invention is preferably 1.0 ⁇ m or less, more preferably 0.005 to 1.0 ⁇ m, and particularly preferably 0.01 to 0.5 ⁇ m.
  • the average particle size of barium titanyl oxalate is in the above range, barium titanate can be produced at a low temperature.
  • the average particle size of barium oxalate titanyl is obtained by arbitrarily measuring 200 particles by a scanning electron microscope (SEM) photograph and using the average value as the average particle size.
  • the barium titanate oxalate of the present invention is a barium oxalate capable of producing barium titanate when heated in a temperature range of 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Barium titanil.
  • a solution containing oxalic acid (solution A) and a solution containing a titanium compound and a barium compound (solution B) are mixed and reacted to cause oxalic acid.
  • a method for producing barium titanyl oxalate, which produces barium titanyl. First, the liquid A is filled in the reaction vessel, and then the liquid B is mixed with the liquid A while stirring the liquid A in the reaction vessel. It is a method for producing barium oxalate titanyl oxalate, characterized in that the time from the start to the end of mixing the liquid B with the liquid A is within 10 seconds.
  • the liquid A according to the method for producing barium oxalate titanyl oxalate of the present invention is a solution containing oxalic acid.
  • the concentration of oxalate ion in the liquid A is not particularly limited, but is preferably 0.1 to 7.0 mol / L, and particularly preferably 0.6 to 5.0 mol / L.
  • the solvent of the liquid A may be a water solvent, an organic solvent, or a mixed solvent thereof, and is preferably an organic solvent from the viewpoint of obtaining fine particles of barium oxalate titanyl oxalate.
  • the organic solvent is not particularly limited as long as it is hydrophilic and inactive with respect to the raw material, and is not particularly limited, such as methanol, ethanol, propanol, butanol, diethyl ether, 1,3-butylene glycol, ethylene glycol, propylene glycol, and di.
  • One or more selected from the group consisting of propylene glycol, glycerol, N, N-dimethylformamide and acetone can be used.
  • the mixing ratio thereof is appropriately selected.
  • the liquid B according to the method for producing barium titanyl oxalate of the present invention is a solution containing a titanium compound and a barium compound.
  • the concentration of titanium ions in the liquid B is not particularly limited, but is preferably 0.04 to 4.0 mol / L, and particularly preferably 0.2 to 3.0 mol / L.
  • the concentration of barium ion in the liquid B is not particularly limited, but is preferably 0.08 to 6.5 mol / L, and particularly preferably 0.4 to 3.0 mol / L.
  • the titanium compound according to the method for producing barium titanyl oxalate of the present invention is not particularly limited, and examples thereof include titanium tetrachloride and titanium lactate.
  • the titanium compound may be one kind or a combination of two or more kinds.
  • As the titanium source titanium tetrachloride is preferable.
  • the barium compound according to the method for producing barium titanyl oxalate of the present invention is not particularly limited, and examples thereof include barium chloride, barium carbonate, barium hydroxide, barium acetate, and barium nitrate.
  • the barium compound may be one kind or a combination of two or more kinds.
  • As the barium compound one or more selected from the group consisting of barium chloride, barium carbonate and barium hydroxide is preferable, and barium chloride is particularly preferable.
  • liquid A is filled in the reaction vessel, and then liquid A is supplied to the liquid A and mixed while stirring the liquid A in the reaction vessel. Then, the reaction for producing barium titanyl oxalate is carried out.
  • the time from the start to the end of the mixing of the B solution with the A solution is within 10 seconds, preferably within 8 seconds. be.
  • the time from the start to the end of mixing the liquid B with the liquid A is within the above range, fine particles of barium oxalate titanyl oxalate can be obtained.
  • the temperature at which the B solution is mixed with the A solution that is, the temperatures of the reaction solution (A solution) and the B solution in the reaction vessel when the B solution is added to the reaction vessel is preferably 40 ° C. or lower, particularly preferably. Is 5 to 30 ° C.
  • the ratio of the total number of moles of titanium and barium in the liquid B to the number of moles of oxalic acid in the liquid A is preferably 0.01 to 20, particularly preferably 0.01 to 20, as the mixing amount of the liquid B to the liquid A.
  • the amount is 0.1 to 10.
  • the reaction may be terminated by adding the entire amount of the B solution to the A solution to complete the mixing of the B solution with the A solution and then removing the reaction solution by filtration or the like, or to the A solution.
  • the reaction liquid may be aged to be maintained at a predetermined temperature for a certain period of time.
  • the aging temperature is preferably 40 ° C. or lower, particularly preferably 5 to 30 ° C.
  • the aging time is preferably 0.5 to 40 hours, particularly preferably 1 to 24 hours.
  • the stirring speed is not particularly limited, but a reaction solution containing barium titanyl oxalate produced from the start of addition of solution B to solution A to the end of addition of the entire amount of solution B, and in the case of aging, until the end of aging.
  • the stirring speed may be such that the stirring speed is always in a flowing state.
  • the reaction solution is solid-liquid separated by a conventional method, and then solid. Rinse the minutes with water.
  • the washing method is not particularly limited, but washing with repulp or the like is preferable in terms of high washing efficiency. After washing, the solid content is dried and, if necessary, pulverized to obtain barium titanyl oxalate.
  • the barium oxalate titanyl oxalate obtained by performing the method for producing barium oxalate titanyl oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. from 600 to 600 in thermogravimetric analysis. It is 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Therefore, the barium titanate oxalate obtained by the method for producing barium titanyl oxalate of the present invention has barium titanate when fired at 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. The resulting barium titanate oxalate.
  • the average particle size of barium oxalate titanyl oxalate obtained by the method for producing barium oxalate titanyl of the present invention is preferably 1.0 ⁇ m or less, more preferably 0.005 to 1.0 ⁇ m, and particularly preferably 0.01 to 0. It is 5.5 ⁇ m.
  • composition of barium titanyl oxalate obtained by the method for producing barium oxalate titanyl of the present invention has a Ba / Ti molar ratio of 0.998 to 1.004, preferably 0.999 to 1.003.
  • Barium titanyl oxalate obtained by the method for producing barium titanyl oxalate of the present invention is suitably used as a raw material for producing barium titanate-based ceramic, which is a dielectric ceramic material.
  • the method for producing barium titanate of the present invention is as follows.
  • the method for producing barium titanate of the present invention is characterized by firing barium titanyl oxalate obtained by the method for producing barium titanate oxalate of the present invention.
  • Oxalic acid-derived organic substances contained in the final product are not preferable because they impair the dielectric properties of the material and cause unstable behavior in the thermal process for ceramicization. Therefore, in the present invention, it is necessary to thermally decompose barium titanyl oxalate by firing to obtain the desired barium titanate and to sufficiently remove organic substances derived from oxalic acid.
  • the firing conditions are such that the firing temperature is preferably 600 to 1200 ° C, more preferably 620 to 1100 ° C. When the firing temperature is less than 600 ° C., only a part of barium titanate is produced, or it is difficult to obtain single-phase barium titanate. On the other hand, when the firing temperature exceeds 1200 ° C., the variation in particle size becomes large.
  • the firing time is preferably 0.5 to 30 hours, more preferably 1 to 20 hours.
  • the firing atmosphere is not particularly limited, and may be any of an inert gas atmosphere, a vacuum atmosphere, an oxidizing gas atmosphere, and the atmosphere, or firing is performed in the atmosphere while introducing steam. You may.
  • Baking may be performed as many times as desired. Alternatively, for the purpose of making the powder characteristics uniform, once fired may be crushed and then re-baked.
  • the barium titanate powder obtained by firing is fragile and block-shaped, but the barium titanate particles themselves have the following specific average particle size and BET specific surface area. It has. That is, the barium titanate powder obtained above has an average particle size of preferably 0.5 ⁇ m or less, more preferably 0.02 to 0.5 ⁇ m, as determined from a scanning electron micrograph (SEM).
  • the BET specific surface area is preferably 2 to 100 m 2 / g, more preferably 2.5 to 50 m 2 / g.
  • the composition of barium titanate obtained by the production method of the present invention preferably has a molar ratio of Ba to Ti (Ba / Ti) of 0.998 to 1.004, particularly preferably 0.999 to 1.003. .
  • the c-axis / a-axis ratio which is an index of crystallinity, is preferably 1.030 to 1.0055, preferably 1.0035 to 1.0050, in the range where the specific surface area of barium titanate is 15 m 2 / g or more. Especially preferable.
  • the specific surface area is in the range of less than 15 m 2 / g, but in that range, the c-axis / a-axis ratio is preferably more than 1.0055, preferably 1.0070 or more. More preferably, 1.0075 or more is particularly preferable.
  • the method for producing barium titanate of the present invention may be prepared by using a compound containing a subcomponent element for the purpose of adjusting the dielectric property and the temperature characteristic as necessary. It can be added to the resulting barium titanate to contain sub-component elements.
  • the subcomponent element-containing compound that can be used include rare earth elements such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. , Ba, Li, Bi, Zn, Mn, Al, Si, Ca, Sr, Co, Ni, Cr, Fe, Mg, Ti, V, Nb, Mo, W and Sn at least one selected from the group. Examples include compounds containing elements.
  • the subcomponent element-containing compound may be either an inorganic substance or an organic substance.
  • oxides containing the above-mentioned elements, hydroxides, chlorides, nitrates, oxalates, carboxylates, alkoxides and the like can be mentioned.
  • the auxiliary component element-containing compound is a compound containing a Si element, silica sol, sodium silicate, or the like can be used in addition to the oxide or the like.
  • the subcomponent element-containing compound may be used alone or in combination of two or more. The addition amount and the combination of the added compounds may be carried out according to a conventional method.
  • barium titanate and a sub-component element-containing compound may be uniformly mixed and then fired.
  • barium titanyl oxalate and a compound containing a subcomponent element may be uniformly mixed and then calcined.
  • a laminated ceramic capacitor is manufactured by using the barium titanate obtained by the method for producing barium titanate of the present invention
  • a powder of barium titanate is added to a conventionally known substance including subcomponent elements. It is mixed and dispersed in an appropriate solvent together with a compounding agent such as an agent, an organic binder, a plasticizing agent, and a dispersant to form a slurry, and sheet molding is performed.
  • a compounding agent such as an agent, an organic binder, a plasticizing agent, and a dispersant to form a slurry, and sheet molding is performed.
  • a ceramic sheet used for manufacturing a monolithic ceramic capacitor is obtained.
  • a conductive paste for forming an internal electrode is printed on one surface of the ceramic sheet.
  • a plurality of the ceramic sheets are laminated and pressure-bonded in the thickness direction to form a laminated body.
  • this laminated body is heat-treated to perform a binder removal treatment, and then fired to obtain a fired body.
  • Ni paste, Ag paste, nickel alloy paste, copper paste, copper alloy paste and the like are applied and baked on the fired body to obtain a laminated ceramic capacitor.
  • the powder of barium titanate obtained by the method for producing barium titanate of the present invention is blended with a resin such as an epoxy resin, a polyester resin or a polyimide resin to form a resin sheet, a resin film, an adhesive or the like. Then, in addition to being able to be used as a material for printed wiring boards and multilayer printed wiring boards, a common material for suppressing the shrinkage difference between the internal electrode and the dielectric layer, an electrode ceramic circuit board, a glass ceramic circuit board, and circuit peripherals. It can also be used as a material and a dielectric material for inorganic EL.
  • a resin such as an epoxy resin, a polyester resin or a polyimide resin to form a resin sheet, a resin film, an adhesive or the like.
  • barium titanate obtained by the method for producing barium titanate of the present invention is used for surface modification of catalysts used in reactions such as exhaust gas removal and chemical synthesis, and printing toners having antistatic and cleaning effects. It is suitably used as a material.
  • Example 1 25.0 g of oxalic acid dihydrate was dissolved in 100 g of ethylene glycol to prepare 120 mL of a solution (solution A) containing an oxalic acid component having oxalic acid of 2.21 mol / L. Separately, 64.4 g of titanium tetrachloride and 32.0 g of barium chloride are dissolved in 210 g of pure water, and the titanium component and barium component having titanium tetrachloride of 0.59 mol / L and barium chloride of 0.63 mol / L are dissolved. 270 mL of a solution (solution B) containing the above was prepared.
  • the solution B was added in 2 seconds, and after holding for 3 hours, solid-liquid separation was performed to obtain a precipitate. After washing this precipitate, it was dried to obtain barium titanyl oxalate.
  • the physical characteristics of the obtained barium oxalate titanyl are as shown in Table 1.
  • the result of having measured the weight loss rate of the obtained barium titanyl oxalate by thermal analysis is shown in FIG. As a result, the weight loss rate at 680 ° C. was 44.90%, which was 99.16% with respect to the weight loss rate of 45.28% at 1000 ° C.
  • the obtained barium titanate oxalate was calcined at 700 ° C. for 2 hours to obtain barium titanate.
  • the physical characteristics of the obtained barium titanate are as shown in Table 1.
  • Example 2 The barium titanate oxalate obtained in Example 1 was calcined at the temperatures shown in Table 1 to obtain barium titanate.
  • Table 1 shows the physical property values of the obtained barium titanate.
  • the solution b was added in 90 seconds, and after holding for 1 hour, solid-liquid separation was performed to obtain a precipitate. After washing this precipitate, it was dried to obtain barium titanyl oxalate.
  • the physical characteristics of the obtained barium oxalate titanyl are as shown in Table 1.
  • the result of having measured the weight loss rate of the obtained barium titanyl oxalate by thermal analysis is shown in FIG. As a result, the weight loss rate at 680 ° C. was 37.71%, which was 84.15% with respect to the weight loss rate of 44.81% at 1000 ° C.
  • the obtained barium oxalate titanyl was calcined at 700 ° C. for 2 hours. However, it was found that barium titanate was not obtained from the measurement result of the weight loss rate of the thermogravimetric analysis.
  • the titanium obtained in the examples was compared with the barium titanate obtained in the comparative example from the comparison of the average particle size, the BET specific surface area and the numerical values of c / a when calcined at the same temperature. It can be seen that barium acid acid is fine and highly crystalline. Further, as shown in FIG. 1, the barium titanate oxalate obtained in Example 1 was obtained as barium titanate at 700 ° C. by thermal weight analysis, whereas the barium titanyl oxalate obtained in Comparative Example 1 was obtained. It can be seen that barium titanate could not be obtained even at 700 ° C.

Abstract

The present invention provides barium titanyl oxalate which makes it possible to obtain barium titanate that has a small particle size and that is highly crystalline. The present invention also provides a method for producing said barium titanyl oxalate in an industrially advantageous manner. The barium titanyl oxalate is characterized in that, in thermogravimetric analysis, the temperature at which the weight reduction rate reaches 99% of the weight reduction rate at 1000°C is 600-700°C. The method for producing said barium titanyl oxalate is a method for producing said barium titanyl oxalate by mixing and reacting a solution (liquid A) containing oxalic acid with a solution (liquid B) containing a titanium compound and a barium compound, and is characterized in that: first the liquid A is filled into a reactor vessel, and subsequently, while stirring the liquid A in the reactor vessel, the liquid B is mixed with the liquid A; and the time from when mixing of the liquid B into the liquid A starts to when said mixing ends is not more than 10 seconds.

Description

シュウ酸バリウムチタニル、その製造方法及びチタン酸バリウムの製造方法Barium oxalate titanyl, its manufacturing method and barium titanate manufacturing method
　本発明は、誘電体、圧電体、オプトエレクトロニクス材、半導体、センサー等の機能性セラミックの原料として有用なシュウ酸バリウムチタニル及びその製造方法に関するものである。 The present invention relates to barium oxalate titanyl oxalate, which is useful as a raw material for functional ceramics such as dielectrics, piezoelectric materials, optoelectronic materials, semiconductors, and sensors, and a method for producing the same.
　従来、チタン酸バリウムは、固相法、水熱合成法、アルコキシド法、シュウ酸塩法等により製造されている。 Conventionally, barium titanate has been produced by a solid phase method, a hydrothermal synthesis method, an alkoxide method, an oxalate method, or the like.
　固相法では、構成原料粉末等を混合し、該混合物を高温で加熱する乾式方法により製造するため、得られた粉末は不規則な形状を呈する凝集体を成し、また、所望の特性を達成するために高温焼成が必要である。また、水熱合成法は、粉体の特性が良好との長所にもかかわらず合成工程が複雑で、オートクレーブを用いるため生産性が劣り、製造粉末の値段が高く工業的に有利でない。また、アルコキシド法も同様、出発物質の取り扱いが難しく、値段が高く工業的に有利でない。 In the solid-phase method, the constituent raw material powder and the like are mixed and the mixture is produced by a dry method of heating at a high temperature. Therefore, the obtained powder forms an agglomerate having an irregular shape and has desired characteristics. High temperature firing is required to achieve this. Further, the hydrothermal synthesis method has the advantages of good powder characteristics, but the synthesis process is complicated, the productivity is inferior because an autoclave is used, the price of the produced powder is high, and it is not industrially advantageous. Similarly, the alkoxide method is difficult to handle as a starting material, is expensive, and is not industrially advantageous.
　シュウ酸塩法で得られるチタン酸バリウムは、水熱合成法やアルコキシド法に比べ、組成が均一なものを安価に製造することができ、また、固相法で製造したチタン酸バリウムに比べ、組成が均一であるという特徴を有する。従来のシュウ酸塩法としては、四塩化チタン等のチタン源、塩化バリウム等のバリウム源及びシュウ酸とを水等の溶媒中で反応させてシュウ酸バリウムチタニルを得た後、該シュウ酸バリウムチタニルを焼成する方法が一般的である（例えば、特許文献１～３参照）。 Barium titanate obtained by the oxalate method can be cheaply produced with a uniform composition as compared with the hydrothermal synthesis method and the alkoxide method, and is compared with barium titanate produced by the solid phase method. It is characterized by a uniform composition. In the conventional oxalate method, a titanium source such as titanium tetrachloride, a barium source such as barium chloride, and oxalic acid are reacted in a solvent such as water to obtain barium titanyl oxalate, and then the barium oxalate is obtained. A method of firing titanyl is common (see, for example, Patent Documents 1 to 3).
特表２００５－５００２３９号公報Special Table 2005-500239 特開２０１０－２０２６１０号公報Japanese Unexamined Patent Publication No. 2010-2062010 特開２０１３－６３８６７号公報Japanese Unexamined Patent Publication No. 2013-63867
　しかし、上記特許文献で得られるシュウ酸バリウムチタニルは、焼成温度が７００℃以上でチタン酸バリウムを生成するものであるため、チタン酸バリウムの生成時点で、結晶化度が低いが、ある程度の粒成長を起こしている。このようなシュウ酸バリウムチタニルを高温で焼成すると、高結晶であっても大粒子となってしまい、機能性セラミックの原料としての特性を満たすことができないという問題があった。 However, since barium titanyl oxalate obtained in the above patent document produces barium titanate at a firing temperature of 700 ° C. or higher, the degree of crystallization is low at the time of production of barium titanate, but some grains are formed. It is growing. When such barium oxalate titanyl oxalate is fired at a high temperature, even high crystals become large particles, and there is a problem that the characteristics as a raw material for functional ceramics cannot be satisfied.
　従って、本発明の目的は、粒径が小さく且つ高結晶のチタン酸バリウムが得られるシュウ酸バリウムチタニルを提供すること、及び該シュウ酸バリウムチタニルを工業的に有利に製造する方法を提供することにある。 Therefore, it is an object of the present invention to provide barium titanate oxalate which can obtain barium titanate having a small particle size and high crystals, and to provide a method for industrially advantageously producing the barium titanate oxalate. It is in.
　本発明者らは、上記実情に鑑み鋭意研究を重ねた結果、シュウ酸を含有する溶液（Ａ液）へのチタン化合物及びバリウム化合物を含有する溶液（Ｂ液）の混合時間を短くすることにより、微細なシュウ酸バリウムチタニルが得られること、このような微細なシュウ酸バリウムチタニルを焼成すると、熱分解の際に炭酸ガスが抜けやすくなり、チタン酸バリウムが生成する温度を下げることができること、そして、低温でチタン酸バリウムを生成させることにより、従来よりも低温でチタン酸バリウムを高結晶化できることから、チタン酸バリウムの粒成長を抑えることができるため、従来に比べ、微粒且つ高結晶なチタン酸バリウムが得られることを見出し、本発明を完成させるに至った。 As a result of diligent research in view of the above circumstances, the present inventors have shortened the mixing time of the solution containing the titanium compound and the barium compound (solution B) with the solution containing oxalate (solution A). , Fine barium titanate oxalate can be obtained, and when such fine barium titanate oxalate is fired, carbon dioxide gas can be easily released during thermal decomposition, and the temperature at which barium titanate is generated can be lowered. By generating barium titanate at a low temperature, barium titanate can be highly crystallized at a lower temperature than before, and thus the grain growth of barium titanate can be suppressed. We have found that barium titanate can be obtained, and have completed the present invention.
　すなわち、本発明（１）は、熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が６００～７００℃であることを特徴とするシュウ酸バリウムチタニルを提供するものである。 That is, the present invention (1) provides barium oxalate titanyl oxalate, which is characterized in that the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is 600 to 700 ° C. in thermogravimetric analysis. Is.
　また、本発明（２）は、大気中７００±１０℃、２時間の加熱試験により、比表面積が１５～２０ｍ２／ｇ、且つ、ｃ／ａが１．００３０～１．００５５のチタン酸バリウムに変換されることを特徴とする（１）のシュウ酸バリウムチタニルを提供するものである。 Further, in the present invention (2), barium titanate having a specific surface area of 15 to 20 m 2 / g and a c / a of 1.030 to 1.0055 by a heating test at 700 ± 10 ° C. in the air for 2 hours. It provides barium titanate oxalate (1), which is characterized by being converted into.
　また、本発明（３）は、平均粒子径が１．０μｍ以下であることを特徴とする（１）又は（２）載のシュウ酸バリウムチタニルを提供するものである。 Further, the present invention (3) provides the barium titanyl oxalate according to (1) or (2), which is characterized in that the average particle size is 1.0 μm or less.
　また、本発明（４）は、シュウ酸を含有する溶液（Ａ液）と、チタン化合物及びバリウム化合物を含有する溶液（Ｂ液）とを混合して、反応させることにより、シュウ酸バリウムチタニルを製造するシュウ酸バリウムチタニルの製造方法であり、
　先に、反応容器に該Ａ液を張り込み、次いで、該反応容器内で該Ａ液を撹拌しながら、該Ａ液に該Ｂ液を混合すること、
　該Ａ液への該Ｂ液の混合を開始してから終了するまでの時間が１０秒以内であること、を特徴とするシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, in the present invention (4), barium titanyl oxalate is produced by mixing a solution containing oxalic acid (liquid A) and a solution containing a titanium compound and a barium compound (solution B) and reacting them. It is a method for producing barium titanyl oxalate to be produced.
First, the liquid A is filled in the reaction vessel, and then the liquid B is mixed with the liquid A while stirring the liquid A in the reaction vessel.
The present invention provides a method for producing barium oxalate titanyl oxalate, characterized in that the time from the start to the end of mixing the liquid B with the liquid A is within 10 seconds.
　また、本発明（５）は、前記Ａ液の溶媒が有機溶媒であることを特徴とする（４）のシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, the present invention (5) provides the method for producing barium oxalate titanyl oxalate (4), which is characterized in that the solvent of the liquid A is an organic solvent.
　また、本発明（６）は、前記Ａ液の溶媒が、メタノール、エタノール、プロパノール、ブタノール、ジエチルエーテル、１，３－ブチレングリコール、エチレングリコール、プロピレングリコール、ジプロピレングリコール、グリセロール、Ｎ，Ｎ－ジメチルホルムアミド及びアセトンからなる群から選ばれる１種又は２種以上であることを特徴とする（５）のシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, in the present invention (6), the solvent of the solution A is methanol, ethanol, propanol, butanol, diethyl ether, 1,3-butylene glycol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol, N, N-. The present invention provides the method for producing barium titanyl oxalate according to (5), which is one or more selected from the group consisting of dimethylformamide and acetone.
　また、本発明（７）は、前記Ｂ液の溶媒が水であることを特徴とする（４）のシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, the present invention (7) provides the method for producing barium oxalate titanyl oxalate (4), which is characterized in that the solvent of the liquid B is water.
　また、本発明（８）は、前記Ｂ液中の前記チタン化合物が四塩化チタンであり、前記バリウム化合物が塩化バリウムであることを特徴とする（４）～（７）いずれかのシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, the present invention (8) is characterized in that the titanium compound in the liquid B is titanium tetrachloride and the barium compound is barium chloride, which is any barium oxalate (4) to (7). It provides a method for producing titanyl.
　また、本発明（９）は、前記Ａ液への前記Ｂ液の混合温度が４０℃以下であることを特徴とする（４）～（８）いずれかのシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, the present invention (9) provides a method for producing barium oxalate titanyl oxalate according to any one of (4) to (8), wherein the mixing temperature of the liquid B with the liquid A is 40 ° C. or lower. It is something to do.
　また、本発明（１０）は、生成されるシュウ酸バリウムチタニルの平均粒子径が１．０μｍ以下であることを特徴とする（４）～（９）いずれかのシュウ酸バリウムチタニルの製造方法を提供するものである。 Further, the present invention (10) is characterized in that the average particle size of barium oxalate titanyl produced is 1.0 μm or less, according to any one of (4) to (9), a method for producing barium oxalate titanyl. It is to provide.
　また、本発明（１１）は、（４）～（１０）いずれかの製造方法で得られたシュウ酸バリウムチタニルを焼成することを特徴とするチタン酸バリウムの製造方法を提供するものである。 Further, the present invention (11) provides a method for producing barium titanate, which comprises calcining barium titanate oxalate obtained by any of the production methods (4) to (10).
　本発明によれば、同じ温度で焼成した場合に、従来のシュウ酸バリウムチタニルに比べ、粒径が小さく且つ高結晶のチタン酸バリウムが得られるシュウ酸バリウムチタニルを提供することができる。また、本発明によれば、該シュウ酸バリウムチタニルを工業的に有利に製造する方法を提供することができる。 According to the present invention, it is possible to provide barium titanate oxalate, which can obtain barium titanate having a smaller particle size and higher crystals than conventional barium titanate oxalate when fired at the same temperature. Further, according to the present invention, it is possible to provide a method for industrially advantageously producing the barium titanyl oxalate.
実施例１及び比較例１で得られたシュウ酸バリウムチタニルの熱重量分析の測定結果である。It is a measurement result of the thermogravimetric analysis of barium titanyl oxalate obtained in Example 1 and Comparative Example 1. 実施例１で得られたシュウ酸バリウムチタニルのＳＥＭ写真である。6 is an SEM photograph of barium titanyl oxalate obtained in Example 1. 実施例１で得られたチタン酸バリウムのＳＥＭ写真である。6 is an SEM photograph of barium titanate obtained in Example 1. 比較例１で得られたシュウ酸バリウムチタニルのＳＥＭ写真である。6 is an SEM photograph of barium oxalate titanyl oxalate obtained in Comparative Example 1. 比較例１で得られた焼成物のＳＥＭ写真である。It is an SEM photograph of the fired product obtained in Comparative Example 1.
　本発明のシュウ酸バリウムチタニルは、熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃であることを特徴とするシュウ酸バリウムチタニルである。なお、熱重量分析における１０００℃の重量減少率とは、熱重量分析での分析温度が１０００℃の時点での重量減少率を指す。また、熱重量分析における１０００℃の重量減少率に対する重量減少率が９９％に達する温度とは、分析開始時に対する重量減少率が、分析温度が１０００℃の時点での重量減少率の９９％に達するときの温度を指す。 The barium oxalate titanyl oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to a weight loss rate of 1000 ° C. at 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685. Barium titanyl oxalate, characterized by a temperature of ° C. The weight loss rate of 1000 ° C. in the thermogravimetric analysis refers to the weight loss rate at the time when the analysis temperature in the thermogravimetric analysis is 1000 ° C. Further, the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate of 1000 ° C. in the thermogravimetric analysis means that the weight loss rate at the start of the analysis is 99% of the weight loss rate at the analysis temperature of 1000 ° C. Refers to the temperature at which it reaches.
　熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度は、シュウ酸バリウムチタニルの熱分解が起こり、チタン酸バリウムへの変化が終了する温度、つまり、シュウ酸バリウムチタニルからチタン酸バリウムを生成する温度を指す。シュウ酸バリウムチタニルの熱重量分析により測定される重量減少については、測定対象試料を室温から１０℃／分で昇温していくと、いくつかの重量減少が確認された後、７００℃近傍で重量減少が確認されなくなり、最終的にチタン酸バリウムまで熱分解されたことが確認できる。従来のシュウ酸バリウムチタニルは、７００～７２０℃で重量減少がなくなり、この温度範囲でチタン酸バリウムが得られていることが確認できる。しかし、本発明のシュウ酸バリウムチタニルは、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃で重量減少が確認できなくなるため、従来技術よりも低温でシュウ酸バリウムチタニルからチタン酸バリウムが得られるものである。この理由としては、後述する本発明のシュウ酸バリウムチタニルの製造方法を行い得られるシュウ酸バリウムチタニルは、その平均粒子径が好ましくは１．０μｍ以下、特に好ましくは０．０１～０．５μｍと微粒なため、熱分解での炭酸ガスが抜け易く、従来技術よりも低温でチタン酸バリウムに変化しているためと本発明者らは考えている。 In the thermal weight analysis, the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is the temperature at which the thermal decomposition of barium titanate oxalate occurs and the conversion to barium titanate ends, that is, barium titanate oxalate. Refers to the temperature at which barium titanate is produced from. Regarding the weight loss measured by thermogravimetric analysis of barium titanate oxalate, when the temperature of the sample to be measured was raised from room temperature to 10 ° C / min, some weight loss was confirmed, and then at around 700 ° C. It can be confirmed that the weight reduction is no longer confirmed, and finally the barium titanate is thermally decomposed. The weight of the conventional barium titanate oxalate disappears at 700 to 720 ° C., and it can be confirmed that barium titanate is obtained in this temperature range. However, the barium titanyl oxalate of the present invention cannot be confirmed to lose weight at 600 to 700 ° C, preferably 610 to 690 ° C, particularly preferably 615 to 685 ° C. Barium titanate can be obtained. The reason for this is that the average particle size of barium titanyl oxalate obtained by the method for producing barium titanyl oxalate of the present invention, which will be described later, is preferably 1.0 μm or less, particularly preferably 0.01 to 0.5 μm. The present inventors consider that the fine particles make it easy for carbon dioxide gas to escape during thermal decomposition and change to barium titanate at a lower temperature than in the prior art.
　本発明のシュウ酸バリウムチタニルは、熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃であることにより、チタン酸バリウムを、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃の温度範囲で生成させることができる。そのため、本発明のシュウ酸バリウムチタニルは、低温でチタン酸バリウムを生成させることができるので、従来よりも低温でチタン酸バリウムを高結晶化できる。そして、本発明のシュウ酸バリウムチタニルでは、従来よりも低温でチタン酸バリウムを高結晶化できることから、チタン酸バリウムの粒成長を抑えることができるので、従来に比べ、微粒且つ高結晶なチタン酸バリウムが得られる。そのため、本発明のシュウ酸バリウムチタニルによれば、同じ温度で焼成したときに、従来のシュウ酸バリウムチタニルに比べ、微細且つ高結晶のチタン酸バリウムを得ることができる。一方、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が７００℃を超えると、シュウ酸バリウムチタニルからチタン酸バリウムを生成する温度が高くなるので、その後の高結晶化のための加熱温度も高くなってしまい、その結果、チタン酸バリウムの粒径が大きくなってしまう。 In the thermogravimetric analysis, the barium titanate oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. is 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685. By the temperature, barium titanate can be produced in the temperature range of 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Therefore, the barium titanate oxalate of the present invention can generate barium titanate at a low temperature, so that barium titanate can be highly crystallized at a lower temperature than before. The barium titanate oxalate of the present invention can crystallize barium titanate at a lower temperature than before, and thus can suppress the grain growth of barium titanate. Barium is obtained. Therefore, according to the barium titanate oxalate of the present invention, finer and higher crystal barium titanate can be obtained as compared with the conventional barium titanate oxalate when fired at the same temperature. On the other hand, when the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate of 1000 ° C exceeds 700 ° C, the temperature at which barium titanate is produced from barium titanyl oxalate becomes high, so that the temperature for subsequent high crystallization can be achieved. The heating temperature also becomes high, and as a result, the particle size of barium titanate becomes large.
　シュウ酸バリウムチタニルの熱重量分析に用いる熱重量分析装置は、特に制限されず、例えば、メトラー・トレド株式会社製のＴＧＡ／ＤＳＣ　１が挙げられる。 The thermogravimetric analyzer used for thermogravimetric analysis of barium titanyl oxalate is not particularly limited, and examples thereof include TGA / DSC 1 manufactured by METTLER TOLEDO CO., LTD.
　本発明のシュウ酸バリウムチタニルは、大気中７００±１０℃、２時間の加熱試験により、比表面積が１５～２０ｍ２／ｇ、且つ、ｃ／ａが１．００３０～１．００５５のチタン酸バリウムに変換されるシュウ酸バリウムチタニルであることが好ましい。本発明のシュウ酸バリウムチタニルを、大気中７００±１０℃、２時間加熱試験して得られるチタン酸バリウムの比表面積は、特に好ましくは１６～１９ｍ２／ｇである。また、本発明のシュウ酸バリウムチタニルを、大気中７００±１０℃、２時間加熱試験して得られるチタン酸バリウムのｃ／ａは、特に好ましくは１．００３５～１．００５０である。大気中７００±１０℃、２時間の加熱試験により生じるチタン酸バリウムの比表面積が上記範囲にあり且つｃ／ａが上記範囲にあることにより、焼成過程において、チタン酸バリウムが生成した後の高結晶化のための加熱で粒成長が起きても、従来のシュウ酸バリウムチタニルに比べ、微細且つ高結晶のチタン酸バリウムを得ることができる。シュウ酸バリウムチタニルの加熱試験については、７００±１０℃に温度調節された加熱装置中に、測定対象試料を２時間保持して加熱試験を行い、冷却後、加熱試験後の測定対象試料をＢＥＴ法による比表面積分析及びＸ線回折分析を行い、加熱試験後の測定対象試料の比表面積及びｃ／ａを求める。 The barium titanyl oxalate of the present invention has a specific surface area of 15 to 20 m 2 / g and a c / a of 1.0030 to 1.0055 by a heating test at 700 ± 10 ° C. for 2 hours in the atmosphere. It is preferably barium titanyl oxalate that is converted to. The specific surface area of barium titanate obtained by heating the barium titanyl oxalate of the present invention in the air at 700 ± 10 ° C. for 2 hours is particularly preferably 16 to 19 m 2 / g. The c / a of barium titanate obtained by heating the barium titanyl oxalate of the present invention in the air at 700 ± 10 ° C. for 2 hours is particularly preferably 1.035 to 1.0050. The specific surface area of barium titanate produced by the heating test at 700 ± 10 ° C. in the air for 2 hours is in the above range, and c / a is in the above range. Even if grain growth occurs due to heating for crystallization, finer and higher crystal barium titanate can be obtained as compared with the conventional barium titanate oxalate. Regarding the heating test of barium titanyl oxalate, the measurement target sample was held for 2 hours in a heating device whose temperature was controlled to 700 ± 10 ° C., and the heating test was performed. After cooling, the measurement target sample after the heating test was BET. Specific surface area analysis and X-ray diffraction analysis by the method are performed to determine the specific surface area and c / a of the sample to be measured after the heating test.
　本発明のシュウ酸バリウムチタニルの平均粒子径は、好ましくは１．０μｍ以下、より好ましくは０．００５～１．０μｍ、特に好ましくは０．０１～０．５μｍである。シュウ酸バリウムチタニルの平均粒子径が上記範囲にあることにより、低温でチタン酸バリウムを生成させることができる。なお、本発明においてシュウ酸バリウムチタニルの平均粒子径は、走査型電子顕微鏡（ＳＥＭ）写真により、任意に２００個の粒子を測定し、その平均値を平均粒子径とする。 The average particle size of barium titanyl oxalate of the present invention is preferably 1.0 μm or less, more preferably 0.005 to 1.0 μm, and particularly preferably 0.01 to 0.5 μm. When the average particle size of barium titanyl oxalate is in the above range, barium titanate can be produced at a low temperature. In the present invention, the average particle size of barium oxalate titanyl is obtained by arbitrarily measuring 200 particles by a scanning electron microscope (SEM) photograph and using the average value as the average particle size.
　また、本発明のシュウ酸バリウムチタニルは、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃の温度範囲で加熱したときに、チタン酸バリウムを生成することができるシュウ酸バリウムチタニルである。 The barium titanate oxalate of the present invention is a barium oxalate capable of producing barium titanate when heated in a temperature range of 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Barium titanil.
　以下、本発明の製造方法をその好ましい実施形態に基づき説明する。
　本発明のシュウ酸バリウムチタニルの製造方法は、シュウ酸を含有する溶液（Ａ液）と、チタン化合物及びバリウム化合物を含有する溶液（Ｂ液）とを混合して、反応させることにより、シュウ酸バリウムチタニルを製造するシュウ酸バリウムチタニルの製造方法であり、
　先に反応容器に該Ａ液を張り込み、次いで、該反応容器内で該Ａ液を撹拌しながら、該Ａ液に該Ｂ液を混合すること、
　該Ａ液への該Ｂ液の混合を開始してから終了するまでの時間が１０秒以内であること、を特徴とするシュウ酸バリウムチタニルの製造方法である。 Hereinafter, the production method of the present invention will be described based on the preferred embodiment thereof.
In the method for producing barium oxalate titanyl oxalate of the present invention, a solution containing oxalic acid (solution A) and a solution containing a titanium compound and a barium compound (solution B) are mixed and reacted to cause oxalic acid. A method for producing barium titanyl oxalate, which produces barium titanyl.
First, the liquid A is filled in the reaction vessel, and then the liquid B is mixed with the liquid A while stirring the liquid A in the reaction vessel.
It is a method for producing barium oxalate titanyl oxalate, characterized in that the time from the start to the end of mixing the liquid B with the liquid A is within 10 seconds.
　本発明のシュウ酸バリウムチタニルの製造方法に係るＡ液は、シュウ酸を含有する溶液である。Ａ液中のシュウ酸イオンの濃度は、特に制限されないが、好ましくは０．１～７．０ｍｏｌ／Ｌ、特に好ましくは０．６～５．０ｍｏｌ／Ｌである。 The liquid A according to the method for producing barium oxalate titanyl oxalate of the present invention is a solution containing oxalic acid. The concentration of oxalate ion in the liquid A is not particularly limited, but is preferably 0.1 to 7.0 mol / L, and particularly preferably 0.6 to 5.0 mol / L.
　Ａ液の溶媒は、水溶媒、有機溶媒、あるいはこれらの混合溶媒が挙げられ、微粒のシュウ酸バリウムチタニルを得る観点から、有機溶媒であることが好ましい。有機溶媒としては、親水性であり原料に対して不活性なものであれば特に制限されず、メタノール、エタノール、プロパノール、ブタノール、ジエチルエーテル、１，３－ブチレングリコール、エチレングリコール、プロピレングリコール、ジプロピレングリコール、グリセロール、Ｎ，Ｎ－ジメチルホルムアミド及びアセトンからなる群から選ばれる１種又は２種以上を用いることができる。水と有機溶媒との混合溶媒、複数の有機溶媒の混合溶媒の場合、これらの混合比は適宜選択される。 The solvent of the liquid A may be a water solvent, an organic solvent, or a mixed solvent thereof, and is preferably an organic solvent from the viewpoint of obtaining fine particles of barium oxalate titanyl oxalate. The organic solvent is not particularly limited as long as it is hydrophilic and inactive with respect to the raw material, and is not particularly limited, such as methanol, ethanol, propanol, butanol, diethyl ether, 1,3-butylene glycol, ethylene glycol, propylene glycol, and di. One or more selected from the group consisting of propylene glycol, glycerol, N, N-dimethylformamide and acetone can be used. In the case of a mixed solvent of water and an organic solvent or a mixed solvent of a plurality of organic solvents, the mixing ratio thereof is appropriately selected.
　本発明のシュウ酸バリウムチタニルの製造方法に係るＢ液は、チタン化合物及びバリウム化合物を含有する溶液である。Ｂ液中のチタンイオンの濃度は、特に制限されないが、好ましくは０．０４～４．０ｍｏｌ／Ｌ、特に好ましくは０．２～３．０ｍｏｌ／Ｌである。また、Ｂ液中のバリウムイオンの濃度は、特に制限されないが、好ましくは０．０８～６．５ｍｏｌ／Ｌ、特に好ましくは０．４～３．０ｍｏｌ／Ｌである。 The liquid B according to the method for producing barium titanyl oxalate of the present invention is a solution containing a titanium compound and a barium compound. The concentration of titanium ions in the liquid B is not particularly limited, but is preferably 0.04 to 4.0 mol / L, and particularly preferably 0.2 to 3.0 mol / L. The concentration of barium ion in the liquid B is not particularly limited, but is preferably 0.08 to 6.5 mol / L, and particularly preferably 0.4 to 3.0 mol / L.
　本発明のシュウ酸バリウムチタニルの製造方法に係るチタン化合物としては、特に制限されず、四塩化チタン、乳酸チタン等が挙げられる。チタン化合物は、１種であっても、２種以上の併用であってもよい。チタン源としては、四塩化チタンが好ましい。 The titanium compound according to the method for producing barium titanyl oxalate of the present invention is not particularly limited, and examples thereof include titanium tetrachloride and titanium lactate. The titanium compound may be one kind or a combination of two or more kinds. As the titanium source, titanium tetrachloride is preferable.
　本発明のシュウ酸バリウムチタニルの製造方法に係るバリウム化合物としては、特に制限されず、塩化バリウム、炭酸バリウム、水酸化バリウム、酢酸バリウム、硝酸バリウム等が挙げられる。バリウム化合物は、１種であっても、２種以上の併用であってもよい。バリウム化合物としては、塩化バリウム、炭酸バリウム及び水酸化バリウムからなる群から選ばれる１種又は２種以上が好ましく、塩化バリウムが特に好ましい。 The barium compound according to the method for producing barium titanyl oxalate of the present invention is not particularly limited, and examples thereof include barium chloride, barium carbonate, barium hydroxide, barium acetate, and barium nitrate. The barium compound may be one kind or a combination of two or more kinds. As the barium compound, one or more selected from the group consisting of barium chloride, barium carbonate and barium hydroxide is preferable, and barium chloride is particularly preferable.
　本発明のシュウ酸バリウムチタニルの製造方法では、反応容器にＡ液を張り込み、次いで、反応容器内でＡ液を撹拌しながら、Ａ液にＢ液を供給して混合することにより、反応容器内で、シュウ酸バリウムチタニルの生成反応を行う。 In the method for producing barium oxalate titanyl oxalate of the present invention, liquid A is filled in the reaction vessel, and then liquid A is supplied to the liquid A and mixed while stirring the liquid A in the reaction vessel. Then, the reaction for producing barium titanyl oxalate is carried out.
　このとき、Ａ液が張り込んである反応容器へのＢ液の混合は、Ａ液に対してＢ液の混合を開始してから終了するまでの時間が１０秒以内、好ましくは８秒以内である。Ａ液へのＢ液の混合を開始してから終了するまでの時間が上記範囲にあることにより、微粒のシュウ酸バリウムチタニルが得られる。 At this time, in the mixing of the B solution into the reaction vessel filled with the A solution, the time from the start to the end of the mixing of the B solution with the A solution is within 10 seconds, preferably within 8 seconds. be. When the time from the start to the end of mixing the liquid B with the liquid A is within the above range, fine particles of barium oxalate titanyl oxalate can be obtained.
　Ａ液へのＢ液を混合するときの温度、すなわち、反応容器にＢ液を添加するときの反応容器内の反応液（Ａ液）及びＢ液の温度は、好ましくは４０℃以下、特に好ましくは５～３０℃である。 The temperature at which the B solution is mixed with the A solution, that is, the temperatures of the reaction solution (A solution) and the B solution in the reaction vessel when the B solution is added to the reaction vessel is preferably 40 ° C. or lower, particularly preferably. Is 5 to 30 ° C.
　Ａ液へのＢ液の混合量は、Ａ液中のシュウ酸のモル数に対するＢ液中のチタン及びバリウムの原子換算の合計モル数の比が、好ましくは０．０１～２０、特に好ましくは０．１～１０となる量である。 The ratio of the total number of moles of titanium and barium in the liquid B to the number of moles of oxalic acid in the liquid A is preferably 0.01 to 20, particularly preferably 0.01 to 20, as the mixing amount of the liquid B to the liquid A. The amount is 0.1 to 10.
　Ａ液にＢ液の全量を添加して、Ａ液へのＢ液の混合を終了した後、ろ過等で反応液を除去することにより、反応を終了させてもよいし、あるいは、Ａ液にＢ液の全量を添加して、Ａ液へのＢ液の混合を終了した後、反応液を所定の温度で一定時間維持する熟成を行ってもよい。熟成を行う場合、熟成温度は、好ましくは４０℃以下、特に好ましくは５～３０℃であり、熟成時間は、好ましくは０．５～４０時間、特に好ましくは１～２４時間である。 The reaction may be terminated by adding the entire amount of the B solution to the A solution to complete the mixing of the B solution with the A solution and then removing the reaction solution by filtration or the like, or to the A solution. After adding the entire amount of the liquid B and completing the mixing of the liquid B with the liquid A, the reaction liquid may be aged to be maintained at a predetermined temperature for a certain period of time. When aging is performed, the aging temperature is preferably 40 ° C. or lower, particularly preferably 5 to 30 ° C., and the aging time is preferably 0.5 to 40 hours, particularly preferably 1 to 24 hours.
　Ａ液にＢ液を添加して混合しているときは、Ａ液を撹拌しながらＢ液の添加を行うことが好ましい。また、Ａ液にＢ液の全量を添加して、Ａ液へのＢ液の混合を終了した後、熟成を行う場合、反応液を撹拌しながら熟成を行うことが好ましい。撹拌速度は、特に制限されないが、Ａ液へのＢ液の添加開始からＢ液の全量添加終了まで、熟成を行う場合は、熟成の終了までの間、生成するシュウ酸バリウムチタニルを含む反応液が、常に流動する状態となる撹拌速度であればよい。 When the liquid B is added to the liquid A and mixed, it is preferable to add the liquid B while stirring the liquid A. Further, when aging is carried out after adding the entire amount of the liquid B to the liquid A and completing the mixing of the liquid B with the liquid A, it is preferable to carry out the aging while stirring the reaction liquid. The stirring speed is not particularly limited, but a reaction solution containing barium titanyl oxalate produced from the start of addition of solution B to solution A to the end of addition of the entire amount of solution B, and in the case of aging, until the end of aging. However, the stirring speed may be such that the stirring speed is always in a flowing state.
　Ａ液へＢ液の全量を添加して、Ａ液へのＢ液の混合を終了した後、熟成を行う場合は、熟成終了後、常法により反応液の固液分離を行い、次いで、固形分を水洗する。水洗方法としては、特に制限されないが、リパルプ等で洗浄を行うことが、洗浄効率が高い点で好ましい。洗浄後、固形分を乾燥し、必要に応じて粉砕してシュウ酸バリウムチタニルを得る。 When the aging is performed after adding the entire amount of the B solution to the A solution and completing the mixing of the B solution with the A solution, after the aging is completed, the reaction solution is solid-liquid separated by a conventional method, and then solid. Rinse the minutes with water. The washing method is not particularly limited, but washing with repulp or the like is preferable in terms of high washing efficiency. After washing, the solid content is dried and, if necessary, pulverized to obtain barium titanyl oxalate.
　このようにして、本発明のシュウ酸バリウムチタニルの製造方法を行い得られるシュウ酸バリウムチタニルは、熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃である。そのため、本発明のシュウ酸バリウムチタニルの製造方法を行い得られるシュウ酸バリウムチタニルは、６００～７００℃、好ましくは６１０～６９０℃、特に好ましくは６１５～６８５℃で焼成したときにチタン酸バリウムが得られるシュウ酸バリウムチタニルである。 In this way, the barium oxalate titanyl oxalate obtained by performing the method for producing barium oxalate titanyl oxalate of the present invention has a temperature at which the weight loss rate reaches 99% with respect to the weight loss rate at 1000 ° C. from 600 to 600 in thermogravimetric analysis. It is 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. Therefore, the barium titanate oxalate obtained by the method for producing barium titanyl oxalate of the present invention has barium titanate when fired at 600 to 700 ° C., preferably 610 to 690 ° C., particularly preferably 615 to 685 ° C. The resulting barium titanate oxalate.
　本発明のシュウ酸バリウムチタニルの製造方法を行い得られるシュウ酸バリウムチタニルの平均粒子径は、好ましくは１．０μｍ以下、より好ましくは０．００５～１．０μｍ、特に好ましくは０．０１～０．５μｍである。 The average particle size of barium oxalate titanyl oxalate obtained by the method for producing barium oxalate titanyl of the present invention is preferably 1.0 μm or less, more preferably 0.005 to 1.0 μm, and particularly preferably 0.01 to 0. It is 5.5 μm.
　本発明のシュウ酸バリウムチタニルの製造方法を行い得られるシュウ酸バリウムチタニルの組成は、Ｂａ／Ｔｉモル比が、０．９９８～１．００４、好ましくは０．９９９～１．００３である。 The composition of barium titanyl oxalate obtained by the method for producing barium oxalate titanyl of the present invention has a Ba / Ti molar ratio of 0.998 to 1.004, preferably 0.999 to 1.003.
　本発明のシュウ酸バリウムチタニルの製造方法により得られるシュウ酸バリウムチタニルは、誘電体セラミック材料のチタン酸バリウム系セラミックの製造原料として好適に用いられる。本発明のチタン酸バリウムの製造方法は以下の通りである。 Barium titanyl oxalate obtained by the method for producing barium titanyl oxalate of the present invention is suitably used as a raw material for producing barium titanate-based ceramic, which is a dielectric ceramic material. The method for producing barium titanate of the present invention is as follows.
　本発明のチタン酸バリウムの製造方法は、本発明のシュウ酸バリウムチタニルの製造方法により得られたシュウ酸バリウムチタニルを焼成することを特徴とするものである。 The method for producing barium titanate of the present invention is characterized by firing barium titanyl oxalate obtained by the method for producing barium titanate oxalate of the present invention.
　最終製品に含まれるシュウ酸由来の有機物は、材料の誘電体特性を損なうとともに、セラミック化のための熱工程における挙動の不安定要因となるので好ましくない。従って、本発明では焼成によりシュウ酸バリウムチタニルを熱分解して目的とするチタン酸バリウムを得ると共に、シュウ酸由来の有機物を十分除去する必要がある。焼成条件は、焼成温度が好ましくは６００～１２００℃、更に好ましくは６２０～１１００℃である。焼成温度が６００℃未満では、チタン酸バリウムが一部しか生成していない、或いは、単一相のチタン酸バリウムが得られにくい。一方、焼成温度が１２００℃を超えると、粒径のバラツキが大きくなる。焼成時間は好ましくは０．５～３０時間、更に好ましくは１～２０時間である。また、焼成雰囲気は、特に制限されず、不活性ガス雰囲気下、真空雰囲気下、酸化性ガス雰囲気下、大気中のいずれであってもよく、或いは水蒸気を導入しながら前記雰囲気中で焼成を行ってもよい。 Oxalic acid-derived organic substances contained in the final product are not preferable because they impair the dielectric properties of the material and cause unstable behavior in the thermal process for ceramicization. Therefore, in the present invention, it is necessary to thermally decompose barium titanyl oxalate by firing to obtain the desired barium titanate and to sufficiently remove organic substances derived from oxalic acid. The firing conditions are such that the firing temperature is preferably 600 to 1200 ° C, more preferably 620 to 1100 ° C. When the firing temperature is less than 600 ° C., only a part of barium titanate is produced, or it is difficult to obtain single-phase barium titanate. On the other hand, when the firing temperature exceeds 1200 ° C., the variation in particle size becomes large. The firing time is preferably 0.5 to 30 hours, more preferably 1 to 20 hours. The firing atmosphere is not particularly limited, and may be any of an inert gas atmosphere, a vacuum atmosphere, an oxidizing gas atmosphere, and the atmosphere, or firing is performed in the atmosphere while introducing steam. You may.
  焼成は所望により何度行ってもよい。或いは、粉体特性を均一にする目的で、一度焼成したものを粉砕し、次いで再焼成を行ってもよい。 Baking may be performed as many times as desired. Alternatively, for the purpose of making the powder characteristics uniform, once fired may be crushed and then re-baked.
  焼成後、適宜冷却し、必要に応じ粉砕してチタン酸バリウムの粉末を得る。必要に応じて行われる粉砕は、焼成して得られるチタン酸バリウムがもろくブロック状のものである場合等に適宜行うが、チタン酸バリウムの粒子自体は下記特定の平均粒径、ＢＥＴ比表面積を有するものである。即ち、前記で得られるチタン酸バリウムの粉末は、走査型電子顕微鏡写真（ＳＥＭ）から求められる平均粒径が好ましくは０．５μｍ以下、更に好ましくは０．０２～０．５μｍである。ＢＥＴ比表面積は、好ましくは２～１００ｍ２／ｇ、更に好ましくは２．５～５０ｍ２／ｇである。更に、本発明の製造方法で得られるチタン酸バリウムの組成は、ＢａとＴｉのモル比（Ｂａ／Ｔｉ）が０．９９８～１．００４、特に０．９９９～１．００３であることが好ましい。また、結晶性の指標となるｃ軸／ａ軸比は、チタン酸バリウムの比表面積が１５ｍ２／ｇ以上の範囲では、１．００３０～１．００５５が好ましく、１．００３５～１．００５０が特に好ましい。焼成温度が高くなると粒成長が生じるため、比表面積が１５ｍ２／ｇ未満の範囲となるが、その範囲では、ｃ軸／ａ軸比は、１．００５５超が好ましくは、１．００７０以上が更に好ましく、１．００７５以上が特に好ましい。 After firing, it is appropriately cooled and pulverized as necessary to obtain barium titanate powder. The pulverization performed as necessary is appropriately performed when the barium titanate obtained by firing is fragile and block-shaped, but the barium titanate particles themselves have the following specific average particle size and BET specific surface area. It has. That is, the barium titanate powder obtained above has an average particle size of preferably 0.5 μm or less, more preferably 0.02 to 0.5 μm, as determined from a scanning electron micrograph (SEM). The BET specific surface area is preferably 2 to 100 m 2 / g, more preferably 2.5 to 50 m 2 / g. Further, the composition of barium titanate obtained by the production method of the present invention preferably has a molar ratio of Ba to Ti (Ba / Ti) of 0.998 to 1.004, particularly preferably 0.999 to 1.003. .. The c-axis / a-axis ratio, which is an index of crystallinity, is preferably 1.030 to 1.0055, preferably 1.0035 to 1.0050, in the range where the specific surface area of barium titanate is 15 m 2 / g or more. Especially preferable. Since grain growth occurs when the firing temperature is high, the specific surface area is in the range of less than 15 m 2 / g, but in that range, the c-axis / a-axis ratio is preferably more than 1.0055, preferably 1.0070 or more. More preferably, 1.0075 or more is particularly preferable.
  また、本発明のチタン酸バリウムの製造方法を行い得られるチタン酸バリウムには、必要により誘電特性や温度特性を調整する目的で、副成分元素含有化合物を本発明のチタン酸バリウムの製造方法を行い得られるチタン酸バリウムに添加して、副成分元素を含有させることができる。用いることができる副成分元素含有化合物としては、例えば、Ｓｃ、Ｙ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕの希土類元素、Ｂａ、Ｌｉ、Ｂｉ、Ｚｎ、Ｍｎ、Ａｌ、Ｓｉ、Ｃａ、Ｓｒ、Ｃｏ、Ｎｉ、Ｃｒ、Ｆｅ、Ｍｇ、Ｔｉ、Ｖ、Ｎｂ、Ｍｏ、Ｗ及びＳｎからなる群より選ばれる少なくとも１種の元素を含有する化合物が挙げられる。 Further, for the barium titanate obtained by the method for producing barium titanate of the present invention, the method for producing barium titanate of the present invention may be prepared by using a compound containing a subcomponent element for the purpose of adjusting the dielectric property and the temperature characteristic as necessary. It can be added to the resulting barium titanate to contain sub-component elements. Examples of the subcomponent element-containing compound that can be used include rare earth elements such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. , Ba, Li, Bi, Zn, Mn, Al, Si, Ca, Sr, Co, Ni, Cr, Fe, Mg, Ti, V, Nb, Mo, W and Sn at least one selected from the group. Examples include compounds containing elements.
  副成分元素含有化合物は、無機物又は有機物のいずれであってもよい。例えば、前記の元素を含む酸化物、水酸化物、塩化物、硝酸塩、蓚酸塩、カルボン酸塩及びアルコキシド等が挙げられる。副成分元素含有化合物がＳｉ元素を含有する化合物である場合は、酸化物等に加えて、シリカゾルや珪酸ナトリウム等も用いることができる。副成分元素含有化合物は１種又は２種以上適宜組み合わせて用いることができる。その添加量や添加化合物の組み合わせは、常法に従って行えばよい。 The subcomponent element-containing compound may be either an inorganic substance or an organic substance. For example, oxides containing the above-mentioned elements, hydroxides, chlorides, nitrates, oxalates, carboxylates, alkoxides and the like can be mentioned. When the auxiliary component element-containing compound is a compound containing a Si element, silica sol, sodium silicate, or the like can be used in addition to the oxide or the like. The subcomponent element-containing compound may be used alone or in combination of two or more. The addition amount and the combination of the added compounds may be carried out according to a conventional method.
  チタン酸バリウムに副成分元素を含有させるには、例えば、チタン酸バリウムと副成分元素含有化合物を均一混合後、焼成を行えばよい。或いは、シュウ酸バリウムチタニルと副成分元素含有化合物を均一混合後、焼成を行ってもよい。 In order to make barium titanate contain a sub-component element, for example, barium titanate and a sub-component element-containing compound may be uniformly mixed and then fired. Alternatively, barium titanyl oxalate and a compound containing a subcomponent element may be uniformly mixed and then calcined.
  本発明のチタン酸バリウムの製造方法を行い得られたチタン酸バリウムを用いて、例えば積層セラミックコンデンサを製造する場合には、先ず、チタン酸バリウムの粉末を、副成分元素を含め従来公知の添加剤、有機系バインダ、可塑剤、分散剤等の配合剤と共に適当な溶媒中に混合分散させてスラリー化し、シート成形を行う。これにより、積層セラミックコンデンサの製造に用いられるセラミックシートを得る。該セラミックシートから積層セラミックコンデンサを作製するには、先ず、該セラミックシートの一面に内部電極形成用導電ペーストを印刷する。乾燥後、複数枚の前記セラミックシートを積層し、厚み方向に圧着することにより積層体とする。次に、この積層体を加熱処理して脱バインダ処理を行い、焼成して焼成体を得る。さらに、該焼成体にＮｉペースト、Ａｇペースト、ニッケル合金ペースト、銅ペースト、銅合金ペースト等を塗布し焼き付けて、積層セラミックコンデンサが得られる。 When, for example, a laminated ceramic capacitor is manufactured by using the barium titanate obtained by the method for producing barium titanate of the present invention, first, a powder of barium titanate is added to a conventionally known substance including subcomponent elements. It is mixed and dispersed in an appropriate solvent together with a compounding agent such as an agent, an organic binder, a plasticizing agent, and a dispersant to form a slurry, and sheet molding is performed. As a result, a ceramic sheet used for manufacturing a monolithic ceramic capacitor is obtained. To manufacture a laminated ceramic capacitor from the ceramic sheet, first, a conductive paste for forming an internal electrode is printed on one surface of the ceramic sheet. After drying, a plurality of the ceramic sheets are laminated and pressure-bonded in the thickness direction to form a laminated body. Next, this laminated body is heat-treated to perform a binder removal treatment, and then fired to obtain a fired body. Further, Ni paste, Ag paste, nickel alloy paste, copper paste, copper alloy paste and the like are applied and baked on the fired body to obtain a laminated ceramic capacitor.
  また、本発明のチタン酸バリウムの製造方法を行い得られたチタン酸バリウムの粉末を、例えばエポキシ樹脂、ポリエステル樹脂、ポリイミド樹脂等の樹脂に配合して、樹脂シート、樹脂フィルム、接着剤等とすると、プリント配線板や多層プリント配線板等の材料として用いることができる他、内部電極と誘電体層との収縮差を抑制するための共材、電極セラミック回路基板、ガラスセラミックス回路基板、回路周辺材料及び無機ＥＬ用の誘電体材料としても用いることができる。 Further, the powder of barium titanate obtained by the method for producing barium titanate of the present invention is blended with a resin such as an epoxy resin, a polyester resin or a polyimide resin to form a resin sheet, a resin film, an adhesive or the like. Then, in addition to being able to be used as a material for printed wiring boards and multilayer printed wiring boards, a common material for suppressing the shrinkage difference between the internal electrode and the dielectric layer, an electrode ceramic circuit board, a glass ceramic circuit board, and circuit peripherals. It can also be used as a material and a dielectric material for inorganic EL.
  また、本発明のチタン酸バリウムの製造方法を行い得られたチタン酸バリウムは、排ガス除去、化学合成等の反応時に使用される触媒や、帯電防止、クリーニング効果を付与する印刷トナーの表面改質材として好適に用いられる。 Further, the barium titanate obtained by the method for producing barium titanate of the present invention is used for surface modification of catalysts used in reactions such as exhaust gas removal and chemical synthesis, and printing toners having antistatic and cleaning effects. It is suitably used as a material.
　以下、本発明を実施例により詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.
（１）シュウ酸バリウムチタニルの熱重量分析
　メトラー・トレド株式会社製熱重量測定装置ＴＧＡ／ＤＳＣ　１を用いて、３０ｍｇの試料を５０ｍＬ／ｍｉｎの空気気流中、３０℃から１２００℃まで昇温速度１０℃／ｍｉｎで測定した。
（２）シュウ酸バリウムチタニル及びチタン酸バリウムの平均粒子径
　走査型電子顕微鏡（ＳＥＭ）写真により、任意に２００個の粒子を測定し、その平均値を平均粒子径とした。
（３）チタン酸バリウムの比表面積
　ＢＥＴ法により求めた。
（４）チタン酸バリウムのｃ／ａ値
　線源としてＣｕ－Ｋα線を用いてＸ線回折装置（Ｂｒｕｋｅｒ社製、Ｄ８　ＡＤＶＡＮＣＥ）により、ｃ軸とａ軸の比ｃ／ａを測定した。 (1) Thermogravimetric analysis of barium titanyl oxalate Using the thermal weight measuring device TGA / DSC 1 manufactured by METTLER TOLEDO Co., Ltd., a 30 mg sample is heated from 30 ° C to 1200 ° C in an air stream of 50 mL / min. It was measured at 10 ° C./min.
(2) Average particle diameters of barium oxalate and barium titanate 200 particles were arbitrarily measured by scanning electron microscopy (SEM) photographs, and the average value was taken as the average particle diameter.
(3) Specific surface area of barium titanate Obtained by the BET method.
(4) c / a value of barium titanate Using Cu—Kα ray as a radiation source, the c-axis to a-axis ratio c / a was measured by an X-ray diffractometer (D8 ADVANCE manufactured by Bruker).
（実施例１）
　シュウ酸２水和物２５．０ｇをエチレングリコール１００ｇに溶解させ、シュウ酸が２．２１ｍｏｌ／Ｌであるシュウ酸成分を含む溶液（Ａ液）１２０ｍＬを調製した。これとは別に、四塩化チタン６４．４ｇ及び塩化バリウム３２．０ｇを純水２１０ｇに溶解させ、四塩化チタンが０．５９ｍｏｌ／Ｌ、塩化バリウムが０．６３ｍｏｌ／Ｌであるチタン成分及びバリウム成分を含む溶液（Ｂ液）２７０ｍＬを調製した。
　次いで、Ａ液を撹拌しながらＢ液を２秒で添加し、その後、３時間保持した後、固液分離して沈殿物を得た。この沈殿物を洗浄後、乾燥してシュウ酸バリウムチタニルを得た。得られたシュウ酸バリウムチタニルの物性値は表１の通りであった。また、得られたシュウ酸バリウムチタニルの熱分析の重量減少率を測定した結果を図１に示す。この結果、６８０℃の重量減少率は４４．９０％であり、１０００℃の重量減少率４５．２８％に対しては９９．１６％であった。
　得られたシュウ酸バリウムチタニルを７００℃で２時間焼成し、チタン酸バリウムを得た。得られたチタン酸バリウムの物性値は表１の通りであった。 (Example 1)
25.0 g of oxalic acid dihydrate was dissolved in 100 g of ethylene glycol to prepare 120 mL of a solution (solution A) containing an oxalic acid component having oxalic acid of 2.21 mol / L. Separately, 64.4 g of titanium tetrachloride and 32.0 g of barium chloride are dissolved in 210 g of pure water, and the titanium component and barium component having titanium tetrachloride of 0.59 mol / L and barium chloride of 0.63 mol / L are dissolved. 270 mL of a solution (solution B) containing the above was prepared.
Then, while stirring the solution A, the solution B was added in 2 seconds, and after holding for 3 hours, solid-liquid separation was performed to obtain a precipitate. After washing this precipitate, it was dried to obtain barium titanyl oxalate. The physical characteristics of the obtained barium oxalate titanyl are as shown in Table 1. Moreover, the result of having measured the weight loss rate of the obtained barium titanyl oxalate by thermal analysis is shown in FIG. As a result, the weight loss rate at 680 ° C. was 44.90%, which was 99.16% with respect to the weight loss rate of 45.28% at 1000 ° C.
The obtained barium titanate oxalate was calcined at 700 ° C. for 2 hours to obtain barium titanate. The physical characteristics of the obtained barium titanate are as shown in Table 1.
（実施例２～４）
　実施例１で得られたシュウ酸バリウムチタニルを表１に示す温度で焼成し、チタン酸バリウムを得た。得られたチタン酸バリウムの物性値を表１示す。 (Examples 2 to 4)
The barium titanate oxalate obtained in Example 1 was calcined at the temperatures shown in Table 1 to obtain barium titanate. Table 1 shows the physical property values of the obtained barium titanate.
（比較例１）
　塩化バリウム２水塩３５．０ｇとシュウ酸２水塩３５．０ｇを純水１２０ｇに溶解させ、バリウム濃度が１．１０ｍｏｌ／Ｌ、シュウ酸濃度が２．２０ｍｏｌ／Ｌであるバリウム成分及びシュウ酸成分を含む溶液（ａ液）１２０ｍＬを調製した。これとは別に、四塩化チタン５４．０ｇを純水に溶解させ、チタン濃度が０．４０ｍｏｌ／Ｌであるチタン成分を含む溶液（ｂ液）２６０ｍＬを調製した。
　次いで、ａ液を撹拌しながらｂ液を９０秒で添加し、その後、１時間保持した後、固液分離して沈殿物を得た。この沈殿物を洗浄後、乾燥してシュウ酸バリウムチタニルを得た。得られたシュウ酸バリウムチタニルの物性値は表１の通りであった。また、得られたシュウ酸バリウムチタニルの熱分析の重量減少率を測定した結果を図１に示す。この結果、６８０℃の重量減少率は３７．７１％であり、１０００℃の重量減少率４４．８１％に対しては８４．１５％であった。
　得られたシュウ酸バリウムチタニルを７００℃で２時間焼成した。しかし、熱重量分析の重量減少率の測定結果からチタン酸バリウムは得られていないことが分かった。 (Comparative Example 1)
Barium chloride dihydrate 35.0 g and oxalic acid dihydrate 35.0 g are dissolved in pure water 120 g, and the barium component and oxalic acid having a barium concentration of 1.10 mol / L and an oxalic acid concentration of 2.20 mol / L are dissolved. 120 mL of a solution (solution a) containing the components was prepared. Separately, 54.0 g of titanium tetrachloride was dissolved in pure water to prepare 260 mL of a solution (liquid b) containing a titanium component having a titanium concentration of 0.40 mol / L.
Then, while the solution a was stirred, the solution b was added in 90 seconds, and after holding for 1 hour, solid-liquid separation was performed to obtain a precipitate. After washing this precipitate, it was dried to obtain barium titanyl oxalate. The physical characteristics of the obtained barium oxalate titanyl are as shown in Table 1. Moreover, the result of having measured the weight loss rate of the obtained barium titanyl oxalate by thermal analysis is shown in FIG. As a result, the weight loss rate at 680 ° C. was 37.71%, which was 84.15% with respect to the weight loss rate of 44.81% at 1000 ° C.
The obtained barium oxalate titanyl was calcined at 700 ° C. for 2 hours. However, it was found that barium titanate was not obtained from the measurement result of the weight loss rate of the thermogravimetric analysis.
（比較例２～４）
　比較例１で得られたシュウ酸バリウムチタニルを表１で示す温度で焼成し、チタン酸バリウムを得た。得られたチタン酸バリウムの物性値を表１に示す。 (Comparative Examples 2 to 4)
The barium titanate oxalate obtained in Comparative Example 1 was calcined at the temperature shown in Table 1 to obtain barium titanate. Table 1 shows the physical characteristics of the obtained barium titanate.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
　表１に示す通り、同じ温度で焼成したときの平均粒径、ＢＥＴ比表面積及びｃ／ａの数値の比較から、比較例で得られたチタン酸バリウムと比べて、実施例で得られたチタン酸バリウムは微粒且つ高結晶であることが判る。また、図１に示す通り、実施例１で得られたシュウ酸バリウムチタニルは、熱重量分析により７００℃においてチタン酸バリウムが得られたが、比較例１で得られたシュウ酸バリウムチタニルは、７００℃でもチタン酸バリウムが得られなかったことが判る。
  As shown in Table 1, the titanium obtained in the examples was compared with the barium titanate obtained in the comparative example from the comparison of the average particle size, the BET specific surface area and the numerical values of c / a when calcined at the same temperature. It can be seen that barium acid acid is fine and highly crystalline. Further, as shown in FIG. 1, the barium titanate oxalate obtained in Example 1 was obtained as barium titanate at 700 ° C. by thermal weight analysis, whereas the barium titanyl oxalate obtained in Comparative Example 1 was obtained. It can be seen that barium titanate could not be obtained even at 700 ° C.

Claims (11)

  1. 　熱重量分析において、１０００℃の重量減少率に対する重量減少率が９９％に達する温度が６００～７００℃であることを特徴とするシュウ酸バリウムチタニル。 In thermogravimetric analysis, barium titanyl oxalate is characterized in that the temperature at which the weight loss rate reaches 99% with respect to the weight loss rate of 1000 ° C is 600 to 700 ° C.
  2. 　大気中７００±１０℃、２時間の加熱試験により、比表面積が１５～２０ｍ２／ｇ、且つ、ｃ／ａが１．００３０～１．００５５のチタン酸バリウムに変換されることを特徴とする請求項１記載のシュウ酸バリウムチタニル。 It is characterized in that a specific surface area of 15 to 20 m 2 / g and c / a of 1.0030 to 1.0055 are converted to barium titanate by a heating test at 700 ± 10 ° C. in the air for 2 hours. The barium titanyl oxalate according to claim 1.
  3. 　平均粒子径が１．０μｍ以下であることを特徴とする請求項１又は２記載のシュウ酸バリウムチタニル。 The barium titanyl oxalate according to claim 1 or 2, wherein the average particle size is 1.0 μm or less.
  4. 　シュウ酸を含有する溶液（Ａ液）と、チタン化合物及びバリウム化合物を含有する溶液（Ｂ液）とを混合して、反応させることにより、シュウ酸バリウムチタニルを製造するシュウ酸バリウムチタニルの製造方法であり、
    　先に、反応容器に該Ａ液を張り込み、次いで、該反応容器内で該Ａ液を撹拌しながら、該Ａ液に該Ｂ液を混合すること、
    　該Ａ液への該Ｂ液の混合を開始してから終了するまでの時間が１０秒以内であること、を特徴とするシュウ酸バリウムチタニルの製造方法。     A method for producing barium oxalate titanyl oxalate, which comprises mixing and reacting a solution containing oxalic acid (solution A) with a solution containing a titanium compound and a barium compound (solution B) to produce barium oxalate titanyl oxalate. And
    First, the liquid A is filled in the reaction vessel, and then the liquid B is mixed with the liquid A while stirring the liquid A in the reaction vessel.
    A method for producing barium oxalate titanyl oxalate, wherein the time from the start to the end of mixing the liquid B with the liquid A is within 10 seconds.
  5. 　前記Ａ液の溶媒が有機溶媒であることを特徴とする請求項４記載のシュウ酸バリウムチタニルの製造方法。 The method for producing barium titanyl oxalate according to claim 4, wherein the solvent of the liquid A is an organic solvent.
  6. 　前記Ａ液の溶媒が、メタノール、エタノール、プロパノール、ブタノール、ジエチルエーテル、１，３－ブチレングリコール、エチレングリコール、プロピレングリコール、ジプロピレングリコール、グリセロール、Ｎ，Ｎ－ジメチルホルムアミド及びアセトンからなる群から選ばれる１種又は２種以上であることを特徴とする請求項５記載のシュウ酸バリウムチタニルの製造方法。 The solvent of the solution A is selected from the group consisting of methanol, ethanol, propanol, butanol, diethyl ether, 1,3-butylene glycol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol, N, N-dimethylformamide and acetone. The method for producing barium titanyl oxalate according to claim 5, wherein the mixture is one kind or two or more kinds.
  7. 　前記Ｂ液の溶媒が水であることを特徴とする請求項４記載のシュウ酸バリウムチタニルの製造方法。 The method for producing barium titanyl oxalate according to claim 4, wherein the solvent of the liquid B is water.
  8. 　前記Ｂ液中の前記チタン化合物が四塩化チタンであり、前記バリウム化合物が塩化バリウムであることを特徴とする請求項４～７いずれか１項記載のシュウ酸バリウムチタニルの製造方法。 The method for producing barium titanyl oxalate according to any one of claims 4 to 7, wherein the titanium compound in the liquid B is titanium tetrachloride, and the barium compound is barium chloride.
  9. 　前記Ａ液への前記Ｂ液の混合温度が４０℃以下であることを特徴とする請求項４～８いずれか１項記載のシュウ酸バリウムチタニルの製造方法。 The method for producing barium oxalate titanyl oxalate according to any one of claims 4 to 8, wherein the mixing temperature of the liquid B with the liquid A is 40 ° C. or lower.
  10. 　生成されるシュウ酸バリウムチタニルの平均粒子径が１．０μｍ以下であることを特徴とする請求項４～９いずれか１項記載のシュウ酸バリウムチタニルの製造方法。 The method for producing barium titanyl oxalate according to any one of claims 4 to 9, wherein the average particle size of the produced barium oxalate titanyl is 1.0 μm or less.
  11. 　請求項４～１０いずれか１項記載の製造方法で得られたシュウ酸バリウムチタニルを焼成することを特徴とするチタン酸バリウムの製造方法。
          A method for producing barium titanate, which comprises calcining barium titanate oxalate obtained by the production method according to any one of claims 4 to 10.
PCT/JP2021/022043 2020-06-12 2021-06-10 Barium titanyl oxalate, method for producing same, and method for producing barium titanate WO2021251451A1 (en)

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WO2012017752A1 (en) * 2010-08-02 2012-02-09 昭和電工株式会社 Titanium oxide sol and process for producing same, ultrafine particulate titanium oxide, process for producing same, and uses of same
JP2013063867A (en) * 2011-09-15 2013-04-11 Nippon Chem Ind Co Ltd Method for producing barium titanyl oxalate and method for producing barium titanate
JP2013151516A (en) * 2013-03-05 2013-08-08 Nippon Chem Ind Co Ltd Method for producing barium titanyl oxalate, and method for producing barium titanate

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WO2012017752A1 (en) * 2010-08-02 2012-02-09 昭和電工株式会社 Titanium oxide sol and process for producing same, ultrafine particulate titanium oxide, process for producing same, and uses of same
JP2013063867A (en) * 2011-09-15 2013-04-11 Nippon Chem Ind Co Ltd Method for producing barium titanyl oxalate and method for producing barium titanate
JP2013151516A (en) * 2013-03-05 2013-08-08 Nippon Chem Ind Co Ltd Method for producing barium titanyl oxalate, and method for producing barium titanate

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