JP2010047428A - Titanium composite salt powder, method for producing the same, and method for producing perovskite type titanium composite oxide powder using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a perovskite type titanium composite oxide powder which is fine and has an X/Ti molar ratio of about 1. <P>SOLUTION: A titanium composite salt powder is provided which includes Ti element, at least one element (X element) selected from Sr, Ca and Mg, a lactate radical and an oxalate radical, and has a BET specific surface area of ≥6 m<SP>2</SP>/g, an X element to Ti element molar ratio (X/Ti) of 0.98-1.02, and infrared absorption spectral peaks at 1,120-1,140 cm<SP>-1</SP>and at 1,040-1,060 cm<SP>-1</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In particular, the present invention contains one or more elements selected from strontium, calcium and magnesium useful as a raw material for functional ceramics such as piezoelectrics, optoelectronic materials, dielectrics, semiconductors, and sensors, and Ti elements. The present invention relates to a titanium composite salt powder, a method for producing the same, and a method for producing a perovskite-type titanium composite salt powder using the same.

  Perovskite-type titanium composite oxides such as perovskite-type strontium titanate, perovskite-type calcium titanate and perovskite-type magnesium titanate have heretofore been used as raw materials for functional ceramics such as piezoelectric bodies and multilayer ceramic capacitors.

Conventionally, a solid phase method is generally used as a method for producing a perovskite-type titanium composite oxide, but there are also wet methods such as a hydrothermal synthesis method, an oxalate method, and an alkoxide method. Of these, the oxalate method is generally a method in which an aqueous solution of TiCl ₄ and XCl ₂ is dropped into an aqueous solution of H ₂ C ₂ O ₄ with stirring to obtain an oxalate, and the oxalate is fired. . The feature of this oxalate method is that the composition of the oxalate obtained is uniform and the target product can be obtained in good yield.

  In recent years, multilayer ceramic capacitors have been required to have an increased number of layers and a higher dielectric constant in order to increase the capacity. For this reason, the perovskite-type titanium composite oxide as a raw material is required to be fine. It has been. Further, it is necessary that the molar ratio of Sr, Ca or Mg element (X element) to Ti element (hereinafter also referred to as “X / Ti molar ratio”) is approximately 1.

  However, in the conventional oxalic acid method, a fine perovskite-type titanium composite oxide cannot be obtained, and further refinement has been demanded.

  Accordingly, an object of the present invention is to provide a perovskite-type titanium composite oxide that is fine and has an X / Ti molar ratio of about 1. Further, the object of the present invention is to sinter a titanium composite salt powder obtained by contacting a solution containing Ti element, X element and a solution containing oxalic acid at a low temperature of about 800 ° C. An object of the present invention is to provide a method for producing a perovskite-type titanium composite oxide in which by-products such as carbonate remain.

  In the course of earnest research on the method for producing a perovskite-type titanium composite oxide powder using the oxalate method, the present inventors have (1) at least one element selected from Ti element and Sr, Ca and Mg. When a titanium composite salt powder is obtained by contacting a solution containing these elements with a solution containing oxalic acid radicals, at least one element selected from Sr, Ca and Mg A fine titanium composite salt powder can be obtained by adding a lactic acid radical to a solution containing the solution and contacting the two solutions in a solvent containing an alcohol; and (2) adding 800 parts of the titanium composite salt powder. Knowing that fine perovskite-type titanium composite oxide powder with stable quality can be obtained without firing by-products such as carbonate even when baked at a low temperature of about ℃, the present invention has been completed. .

That is, the present invention (1) contains Ti element, at least one element selected from Sr, Ca and Mg (X element), a lactic acid radical and an oxalic acid radical, and has a BET specific surface area of 6 m ^2. / G or more, the molar ratio of X element to Ti element (X / Ti) is 0.98 to 1.02, and the peak top is 1120 to 1140 cm ⁻¹ and 1040 to 1060 cm ^−1. The present invention provides a titanium composite salt powder characterized by comprising:

  In the present invention (2), a solution (solution A) containing Ti element, at least one element (X element) selected from Sr, Ca and Mg, and a lactic acid radical, The present invention provides a method for producing a titanium composite salt powder, which comprises contacting a contained solution (solution B) in a solvent containing alcohol.

  According to the present invention, it is possible to provide a perovskite-type titanium composite oxide that is fine and has an X / Ti molar ratio of approximately 1. Further, according to the present invention, even when the titanium composite salt powder obtained by contacting a solution containing Ti element, X element and a solution containing oxalic acid is fired at a low temperature of about 800 ° C., It is possible to provide a method for producing a perovskite-type titanium composite oxide in which by-products such as carbonate remain.

The titanium composite salt powder of the present invention is
(1) Ti element;
(2) at least one element (X element) selected from Sr, Ca and Mg;
(3) lactate root,
(4) contains oxalate radicals,
BET specific surface area is 6 m ² / g or more, molar ratio of X element to Ti element (X / Ti) is 0.98 to 1.02, peak tops are 1120 to 1140 cm ⁻¹ and 1040 to 1060 cm ^−1. The titanium composite salt powder having an infrared absorption spectrum peak in the above.

  The titanium composite salt powder of the present invention contains at least one element of Ti element and X element, that is, one or more elements of Sr, Ca and Mg as metal elements. That is, the titanium composite salt powder of the present invention contains Ti element and Sr element, Ti element and Ca element, Ti element and Mg element, Ti element, Sr element and Ca element. Contains Ti element, Sr element and Mg element, contains Ti element, Ca element and Mg element, or contains Ti element, Sr element, Ca element and Mg element.

  In the titanium composite salt powder of the present invention, the molar ratio (X / Ti) in terms of atoms of X element and Ti element is 0.98 to 1.02, preferably 0.99 to 1.01. When the molar ratio in terms of atoms of the X element and the Ti element is in the above range, it is suitably used as a raw material for producing the perovskite type titanium composite oxide powder. In addition, when the titanium composite salt powder of the present invention contains two or more X elements, the molar ratio is calculated by the total number of moles of X elements in terms of atoms.

The titanium composite salt powder of the present invention contains a lactic acid radical in the chemical structure. Therefore, in the infrared absorption spectrum, the titanium composite salt powder of the present invention has infrared absorption spectrum peaks derived from lactic acid roots, that is, infrared absorption spectrum peaks whose peak top positions are 1120 to 1140 cm ⁻¹ and 1040 to 1060 cm ^−1. Have

  Furthermore, the titanium composite salt powder of the present invention also includes oxalate groups in the chemical structure.

The BET specific surface area of the titanium composite salt powder of the present invention is 6 m ² / g or more, preferably 10 m ² / g or more, particularly preferably 20 m ² / g or more. Therefore, the titanium composite salt powder of the present invention is a finer particle powder than the oxalate powder obtained by the usual oxalic acid method.

  The titanium composite salt powder of the present invention comprises a solution (solution A) containing Ti element, at least one element selected from Sr, Ca and Mg (X element), and a lactic acid radical, and an oxalate radical. This is a titanium composite salt powder obtained by bringing the solution (solution B) into contact with a solvent containing alcohol.

  Although the chemical composition of the titanium composite salt powder of the present invention is not clear, it is considered to be a composite organic acid salt containing X element and Ti element in the above range, and further containing oxalate and lactate radicals. It is done. Therefore, as described later, the titanium composite salt powder of the present invention is baked and treated with a deorganic acid, whereby the titanium composite salt powder of the present invention is easily converted into a perovskite-type titanium composite oxide powder. be able to.

  In addition to the above characteristics, the titanium composite salt powder of the present invention has a chlorine content of 100 ppm or less, preferably 50 ppm or less, and is substantially free of chlorine. This is preferable in terms of ensuring reliability.

  In addition, the titanium composite salt powder of the present invention can further contain subcomponent elements for the purpose of adjusting the dielectric characteristics and temperature characteristics of the perovskite-type titanium composite oxide powder described later. Examples of contained subcomponent elements include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu rare earth elements, Li, At least one selected from Bi, Zn, Mn, Al, Ca, Sr, Ba, Co, Ni, Cr, Fe, Mg, Zr, Hf, V, Nb, Ta, Mo, W, Sn, and Si Elements. The content of the subcomponent element can be arbitrarily set according to the intended dielectric properties, but the content is 0.001 to 20% by mass in terms of atoms with respect to the perovskite-type titanium composite oxide powder. It is.

  The titanium composite salt powder of the present invention is suitably produced by the following method for producing the titanium composite salt powder of the present invention.

  The method for producing a titanium composite salt powder of the present invention includes a solution (solution A) containing Ti element, at least one element selected from Sr, Ca and Mg (X element), and a lactic acid root, It is a manufacturing method of the titanium composite salt powder which contacts the solution (B liquid) containing an oxalate group in the solvent containing alcohol. In addition, making it contact in the solvent containing alcohol means making it contact in the solvent containing alcohol, and in other words, making it contact in presence of alcohol.

  The liquid A according to the method for producing a titanium compound of the present invention includes (1) Ti element, (2) at least one element (X element) selected from Sr, Ca, and Mg, and (3) lactic acid root. And containing.

  As the Ti element source in the liquid A, titanium alkoxide, titanium alkoxide hydrolyzed with water, or an aqueous solution of titanium salt such as titanium chloride or titanium sulfate was hydrolyzed with an alkaline solution such as ammonia or sodium hydroxide. Things. Of these, titanium alkoxides are preferred in that the by-product is only alcohol and contamination of chlorine and other impurities can be avoided. Specific examples of the titanium alkoxide include, for example, titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, etc., and titanium butoxide is easily available industrially, and the stability of the raw material itself The butanol produced by separation is particularly preferable from the standpoint of various physical properties such as easy handling. The titanium alkoxide is used as a solution dissolved in a solvent such as alcohol.

  In addition, in this invention, the Ti element source in A liquid is a raw material for A liquid preparation used for preparation of A liquid. That is, the liquid A is prepared by adding a Ti element source that is a raw material for preparing the liquid A to the solvent. The same applies to the X element source, the lactic acid root source, and the subcomponent element source in the liquid A described later.

  As at least one element source (X element source) selected from Sr, Ca and Mg in the liquid A, for example, hydroxide, chloride, nitrate, carbonate, acetate of strontium, calcium or magnesium , Lactate or alkoxide. Of these, hydroxides are preferred because they are inexpensive and can be reacted without the inclusion of chlorine or other impurities.

  Examples of the lactic acid root source in the liquid A include alkali metal lactic acid salts such as lactic acid, sodium lactate, and potassium lactate, and ammonium lactate. Among these, lactic acid is free from by-products and can avoid contamination with unnecessary impurities. Is preferable.

  Titanium lactate such as hydroxybis (lactato) titanium is also used as both the Ti element source and the lactic acid root source in the liquid A.

  The A liquid is obtained by adding the Ti element source, the X element source, and the lactic acid root source in the A liquid to the solvent. The solvent for the liquid A is water or alcohol or a mixed solvent of water and alcohol. As alcohol which concerns on the solvent of A liquid, 1 type (s) or 2 or more types, such as methanol, ethanol, propanol, isopropanol, butanol, are mentioned, for example.

  The liquid A is preferably prepared by first mixing a Ti element source and a lactic acid root source and then adding an X element source in that a fine titanium composite salt powder can be obtained. Particularly preferred is a mixture prepared by mixing a titanium alkoxide and a lactic acid root source and then adding an X element source. First, a stable transparent solution in which a Ti element source, particularly titanium alkoxide is dissolved can be prepared by mixing a Ti element source, particularly titanium alkoxide and a lactic acid root source, and bringing them into contact with each other. A powder is obtained.

  Therefore, the liquid A is prepared by performing the first step of mixing the Ti element source and the lactic acid root source and the second step of adding the X element source to the solution obtained in the first step. It is particularly preferable in that a stable quality can be obtained.

  As the first step related to the liquid A, a Ti element source is added to an aqueous solution in which a lactic acid root source is dissolved, an alcohol solution in which a lactic acid root source is dissolved, or a mixed solvent solution of water and alcohol in which a lactic acid root source is dissolved. Add a lactic acid root source to an aqueous solution containing an element source, an alcohol solution containing a Ti element source, a mixed solvent solution of water and alcohol containing a Ti element source, or a suspension containing a Ti element source, or In the case of a liquid Ti element source, a method in which a lactic acid root source is added as it is, and then water, alcohol, or water and alcohol are added.

  The content of the lactic acid root in the liquid A is an amount that is 2 to 10, preferably 4 to 8, in terms of the ratio of the number of moles in terms of lactic acid to the number of moles of Ti in terms of atoms (lactic acid / Ti). If the ratio of the number of moles in terms of lactic acid to the number of moles in terms of atoms of the Ti element in the liquid A is less than the above range, it is difficult to obtain a solution in which a stable Ti element is dissolved. The effect is saturated and is not industrially advantageous. The temperature at which the lactic acid root source is added is not particularly limited as long as it is equal to or higher than the freezing point of the solvent used.

  The blending amount of water or alcohol in this first step is usually such that the concentration of Ti element is 0.05 to 1.7 mol / L, preferably 0.1 to 0.7 mol / L in terms of atoms, and the concentration of lactic acid roots. Is preferably in an amount of 0.1 to 17 mol / L, preferably 0.4 to 5.6 mol / L in terms of lactic acid.

  Next, in the second step related to the liquid A, an X element source is added to the solution obtained in the first step. The addition amount of the X element source added to the liquid A is 0.93 to 1.02, preferably 0. 0, in terms of the molar ratio (X / Ti) of the X element to the atomic number of the Ti element. The amount is 95 to 1.00. If the molar ratio (X / Ti) of the X element to the atomic number of Ti element is less than 0.93, the X / Ti molar ratio of the titanium composite salt powder is less than 0.98, If it exceeds 0.02, the X / Ti molar ratio of the titanium composite salt powder exceeds 1.02. The temperature at which the X element source is added is not particularly limited as long as it is equal to or higher than the freezing point of the solvent used.

  After performing the 2nd process which concerns on A liquid, you may adjust a density | concentration with water, alcohol, or water and alcohol as needed.

  The concentration of each component in the liquid A is 0.05 to 1.7 mol / L, preferably 0.1 to 0.7 mol / L in terms of atoms for Ti element, and 0.0465 to 1.0.1 in terms of atoms for X element. 734 mol / L, preferably 0.095 to 0.7 mol / L, and the lactic acid root is 0.1 to 17 mol / L, preferably 0.4 to 5.6 mol / L in terms of lactic acid.

  In addition, the liquid A can further contain subcomponent elements as necessary for the purpose of adjusting the dielectric characteristics and temperature characteristics of the perovskite-type titanium composite oxide powder described later. Subcomponent elements contained in the liquid A include, for example, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu rare earths. Element, Li, Bi, Zn, Mn, Al, Ca, Sr, Ba, Co, Ni, Cr, Fe, Mg, Zr, Hf, V, Nb, Ta, Mo, W, Sn, and Si There may be at least one element. Examples of the sub-component element source include acetate, carbonate, nitrate, lactate or alkoxide of the sub-component element. The content of the subcomponent element is arbitrarily set according to the intended dielectric properties. For example, the total mass in terms of atoms of the subcomponent element is 0.001 to 20 with respect to the perovskite-type titanium composite oxide powder. % By mass.

  B liquid which concerns on the manufacturing method of the titanium composite salt powder of this invention contains an oxalate group. Liquid B is obtained by adding the oxalic acid root source to water or alcohol or a mixed solvent of water and alcohol. Examples of the oxalic acid source relating to the liquid B include oxalic acid dihydrate and succinic anhydride. As alcohol which concerns on the solvent of B liquid, 1 type (s) or 2 or more types, such as methanol, ethanol, propanol, isopropanol, butanol, are mentioned, for example.

  In addition, in this invention, the oxalic acid root source in B liquid is a raw material for B liquid preparation used for preparation of B liquid. That is, B liquid is prepared by adding the oxalic acid root source which is a raw material for preparation of B liquid to a solvent.

  The concentration of the succinic acid radical in the B liquid is usually 0.04 to 5.1 mol / L, preferably 0.1 to 2.1 mol / L in terms of oxalic acid. It is preferable that the concentration of the succinate group in the liquid B is in the above range because the yield of the titanium composite salt powder is increased.

  And in the manufacturing method of the titanium composite salt powder of this invention, titanium composite salt powder is obtained by making A liquid and B liquid contact in the solvent containing alcohol. The temperature at which the liquid A and the liquid B are brought into contact is preferably 5 to 60 ° C, particularly preferably 10 to 40 ° C.

In the method for producing a titanium composite salt powder of the present invention, as an example of a method of contacting A liquid and B liquid in a solvent containing alcohol,
(1) A method of adding B solution to A solution or adding A solution to B solution (hereinafter also referred to as contact method (1)),
(2) A method (also referred to as contact method (2)), which is performed by adding the B liquid to the C liquid while adding the A liquid to the solvent containing alcohol (C liquid).
Is mentioned. The contact method (2) is preferable in that a powder having a uniform chemical composition ratio can be produced.

In the case of the contact method (1), the solution A is an aqueous solution or alcohol containing Ti element, one or more elements selected from Sr, Ca and Mg (element X) and a lactic acid root. In addition, the B liquid is a solution containing an alcohol containing an oxalate group. An aqueous solution containing Ti element, X element and lactic acid radical or a solution containing alcohol is an aqueous solution containing Ti element, X element and lactic acid root, Ti element, X element and lactic acid. An alcohol solution containing roots, or a mixed solvent solution of water and alcohol containing Ti element, X element and lactic acid root. Moreover, the solution containing the alcohol containing an oxalate group is an alcohol solution containing an oxalate group or a mixed solvent solution of water and alcohol containing an oxalate group. That is, in the case of the contact method (1), the solvent of the liquid A may be either an aqueous solvent, an alcohol solvent, or a mixed solvent of water and alcohol, but the solvent of the liquid B may be a solvent containing alcohol, that is, an alcohol solvent or It is a mixed solvent of water and alcohol. The solvent of the liquid B is more preferable as the alcohol concentration is higher. However, in the case of the contact method (1), the liquid B does not contain water at all, but contains water within a range that does not hinder the effects of the present invention. You may go out. For example, hydrated water hydrated to the oxalate root, hygroscopic water absorbed by the oxalate root, etc. are acceptable. Further, when preparing the solution B by adding an aqueous solution of an oxalate root source to an alcohol solvent, it is permissible if the water content in the solution B after preparation is in a range that does not impede the effects of the present invention. . The content of water in the liquid B is preferably 30% by mass or less, particularly preferably 15% by mass or less. In addition, when the solvent of the liquid A is alcohol or a mixed solvent of water and alcohol, the content of water in the liquid A is not particularly limited, but the content of water is easy to obtain a fine titanium composite salt powder. It is more preferable that there is little.
In addition, the contact method (1) may be, for example, a method in which the liquid A and the liquid B are joined in a pipe and contacted. In this case, the length of the tube, the shape of the tube, the tube diameter and the like are not particularly limited as long as the product precipitates in the tube. Examples of such a pipe include a static mixer, a Teflon (registered trademark) tube, and a PVC hose. Further, the reaction can be carried out while introducing air or an inert gas into the pipe for the purpose of smoothly feeding the A liquid and B liquid in the pipe.

  In the case of the contact method (2), the liquid A is a solution containing an aqueous solution or alcohol containing Ti element, one or more elements selected from Sr, Ca, and Mg (X element) and a lactic acid root. In addition, the B liquid is an aqueous solution containing oxalic acid radicals or a solution containing alcohol. An aqueous solution containing Ti element, X element and lactic acid radical or a solution containing alcohol is an aqueous solution containing Ti element, X element and lactic acid root, Ti element, X element and lactic acid. An alcohol solution containing roots, or a mixed solvent solution of water and alcohol containing Ti element, X element and lactic acid root. Moreover, the aqueous solution containing an oxalate radical or the solution containing alcohol is an aqueous solution containing an oxalate radical, an alcohol solution containing an oxalate radical, or a mixed solvent solution of water and alcohol containing an oxalate radical. That is, in the contact method (2), the solvent of the liquid A may be either an aqueous solvent, an alcohol solvent, or a mixed solvent of water and alcohol, and the solvent of the liquid B may be an aqueous solvent, an alcohol solvent, water or an alcohol. Any of the mixed solvents may be used. In addition, when the solvent of the liquid A is an alcohol solvent or a mixed solvent of water and alcohol, the content of water in the liquid A is not particularly limited, but it is easy to obtain a fine titanium composite salt powder. A smaller amount is more preferred. In addition, when the solvent of the liquid B is an alcohol solvent or a mixed solvent of water and alcohol, the content of water in the liquid B is not particularly limited, but it is easy to obtain a fine titanium composite salt powder. A lower content is more preferable.

  C liquid which concerns on a contact method (2) is a solvent containing alcohol, ie, an alcohol solvent, or a mixed solvent of water and alcohol. The higher the alcohol concentration, the more preferable the solvent containing alcohol of the liquid C. However, in the case of the contact method (2), it does not mean that the liquid C should not contain any water, and does not interfere with the effects of the present invention. It may contain water. As alcohol which concerns on C liquid, 1 type (s) or 2 or more types, such as methanol, ethanol, propanol, isopropanol, butanol, are mentioned, for example, The same thing as alcohol of A liquid or B liquid is preferable. The content of water in the liquid C is preferably 30% by mass or less, particularly preferably 15% by mass or less.

  In the case of the contact method (2), the liquid B is added to the liquid C while the liquid A is added to the liquid C, but “the liquid B is added to the liquid C while the liquid A is added to the liquid C. "To" means that the addition time of the A liquid to the C liquid and the addition time of the B liquid to the C liquid are completely or partially overlapped. And the addition time of the A liquid to the C liquid and the addition time of the B liquid to the C liquid are completely overlapped, that is, the addition start of the A liquid and the addition start of the B liquid are simultaneous and A The end of the addition of the liquid and the end of the addition of the B liquid are preferable in terms of easy composition adjustment in the titanium composite salt powder, but both are completely complete as long as the effects of the present invention are not impaired. It does not need to overlap, and it is sufficient that the liquid B is added at least while the liquid A is added.

  In the method for producing a titanium composite salt powder of the present invention, the amounts of the liquid A and the liquid B when the liquid A and the liquid B are brought into contact with each other are oxalic acid in the liquid B with respect to the number of moles of the Ti element in terms of atoms. It is preferable that the ratio of the number of moles in terms of oxalic acid of the root (oxalic acid / Ti) is usually in an amount of 1.3 to 2.3 because a titanium composite salt powder can be obtained in a high yield. Moreover, the stirring speed at the time of making A liquid and B liquid contact is sufficient if the slurry containing the titanium composite salt powder produced | generated between the start of addition until the end of reaction always shows a fluidity | liquidity, and is especially limited. Is not to be done. Moreover, the contact temperature at the time of making it contact with A liquid and B liquid will not be specifically limited if it is below the boiling point of a solvent to be used, and more than a freezing point. The addition time of each liquid when contacting A liquid and B liquid is 30 seconds to 180 minutes, preferably from 1 minute to 60 minutes from an industrial viewpoint, and titanium obtained when continuously performed at a constant rate. The X / Ti molar ratio of the composite salt powder is about 1, and it is preferable because it has a stable quality with little variation and can efficiently obtain a product within the above range.

  In the method for producing a titanium composite salt powder of the present invention, after completion of the addition of the liquid A and the liquid B, aging is performed to continue stirring the reaction liquid as necessary. When this aging is performed, the production reaction of the titanium composite salt powder is completed, so that the BET specific surface area and the X / Ti molar ratio within the above ranges are 0.98 to 1.02, preferably 0.99 to 1.01. A titanium composite salt powder with little variation in composition can be obtained. The aging temperature is not particularly limited, but is preferably 10 to 50 ° C., and the aging time may be 3 minutes or more. The aging temperature refers to the temperature of the entire reaction liquid after the addition of the liquid A and the liquid B.

  After the addition of liquid A and liquid B, or when ripening is performed, after aging, solid-liquid separation is performed by a conventional method, and washing, drying, and pulverization are performed as necessary to obtain a target titanium composite salt powder. In the method for producing a titanium composite salt powder according to the present invention, when titanium alkoxide is used as the Ti element source and hydroxide is used as the X element source, the cleaning can be performed without performing a cleaning step of cleaning impurities such as chlorine. A product having a high purity can be obtained, and there is an advantage that a cleaning step for cleaning impurities such as chlorine can be omitted.

Thus, the titanium composite salt powder obtained by carrying out the method for producing the titanium composite salt powder of the present invention has an X / Ti molar ratio of 0.98 to 1.02, preferably 0.99 to 1.01. Infrared absorption spectrum peaks having a BET specific surface area of 6 m ² / g or more, preferably 10 m ² / g or more, particularly preferably 20 m ² / g or more, and peak tops of 1120 to 1140 cm ⁻¹ and 1040 to 1060 cm ^−1. It is preferable that the chlorine content is 100 ppm or less, preferably 50 ppm or less.

  The method for producing a perovskite type titanium composite oxide powder of the present invention is a method for producing a perovskite type titanium composite oxide powder by firing the titanium composite salt powder of the present invention. The perovskite-type titanium composite oxide refers to perovskite-type titanium composite oxides such as perovskite-type strontium titanate, perovskite-type calcium titanate, and perovskite-type magnesium titanate.

  Organic substances derived from oxalate and lactic acid radicals contained in the perovskite-type titanium composite oxide powder are not preferable because they impair the dielectric characteristics of the material and cause unstable behavior in the thermal process for ceramization. Therefore, in the method for producing a perovskite-type titanium composite oxide powder of the present invention, the titanium composite salt powder of the present invention is thermally decomposed by firing to obtain a perovskite-type titanium composite oxide powder. The organic matter is sufficiently removed.

  In the method for producing a perovskite-type titanium composite oxide powder of the present invention, the firing temperature is 600 to 950 ° C, preferably 700 to 850 ° C. If the firing temperature is less than the above range, the formation reaction of the perovskite type titanium composite oxide due to thermal decomposition is difficult to complete, while if it exceeds the above range, the target fine powder perovskite type titanium composite is used for grain growth. It becomes difficult to obtain oxide powder. The firing atmosphere is not particularly limited, and may be any of air, reduced pressure, oxygen or an inert gas atmosphere. Moreover, you may perform baking as many times as desired. Alternatively, for the purpose of making the powder characteristics uniform, the fired material may be pulverized and then refired. Alternatively, the titanium composite salt powder may be heated at 230 ° C. or higher and lower than 600 ° C. in air, and then fired at 600 ° C. or higher and 950 ° C. or lower under reduced pressure.

  After firing, the mixture is appropriately cooled and pulverized as necessary to obtain a perovskite-type titanium composite oxide powder. The pulverization performed as necessary is performed as appropriate when the perovskite-type titanium composite oxide powder obtained by firing is in a brittlely bonded block form, but the perovskite-type titanium composite oxide powder itself Has the following specific average particle diameter and BET specific surface area.

That is, the perovskite type titanium composite oxide powder obtained by carrying out the method for producing the perovskite type titanium composite oxide powder of the present invention has an average particle size determined from a scanning electron microscope (SEM) of usually 0.02 to 0.00. The particle diameter is 3 μm, preferably 0.05 to 0.15 μm, the BET specific surface area is 6 m ² / g or more, preferably 8 to ²⁰ m ² / g, and there is little variation in particle size. Further, the perovskite-type titanium composite oxide powder obtained by carrying out the method for producing a perovskite-type titanium composite oxide powder of the present invention has a chlorine content of preferably 100 ppm or less, more preferably 50 ppm or less in addition to the above physical properties. Further, the molar ratio of X / Ti is 0.98 to 1.02, preferably 0.99 to 1.01, and the crystallinity is excellent.

  The perovskite-type titanium composite oxide powder obtained by performing the method for producing a perovskite-type titanium composite oxide powder of the present invention is used to obtain a ceramic sheet for producing a multilayer ceramic capacitor, for example, producing a multilayer ceramic capacitor Above, perovskite type titanium composite oxide powder obtained by carrying out the method for producing the perovskite type titanium composite oxide powder of the present invention is suitable together with compounding agents such as conventionally known additives, organic binders, plasticizers, dispersants, etc. A ceramic sheet used for the production of a multilayer ceramic capacitor can be obtained by mixing and dispersing in a suitable solvent to form a slurry, followed by sheet forming.

  In order to produce a multilayer ceramic capacitor from a ceramic sheet, first, a conductive paste for forming an internal electrode is printed on one surface of the ceramic sheet, and after drying, a plurality of the ceramic sheets are laminated and laminated by pressing in the thickness direction. Let it be the body. Next, this laminate is heat treated to remove the binder, and fired to obtain a fired body. Furthermore, a multilayer capacitor can be obtained by applying Ni paste, Ag paste, nickel alloy paste, copper paste, copper alloy paste and the like to the sintered body and baking it.

  Further, for example, a perovskite-type titanium composite oxide powder obtained by performing the method for producing a perovskite-type titanium composite oxide powder of the present invention is blended with a resin such as an epoxy resin, a polyester resin, a polyimide resin, etc. For films, adhesives, etc., materials such as printed wiring boards and multilayer printed wiring boards, co-materials for suppressing shrinkage differences between internal electrodes and dielectric layers, electrode ceramic circuit boards, glass ceramic circuit boards and circuit peripherals It can be used as a material.

  In addition, the perovskite type titanium composite oxide powder obtained by the method for producing the perovskite type titanium composite oxide powder of the present invention provides a catalyst used in reactions such as exhaust gas removal, chemical synthesis, and antistatic and cleaning effects. It is suitably used as a surface modifier for printing toner.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Example 1
(Preparation of liquid B)
6.67 g of oxalic acid dihydrate was dissolved in 100 ml of ethanol at 25 ° C. to prepare a solution B.
(Preparation of solution A)
After adding 18.22 g of lactic acid to 8.56 g of tetra-n-butyl titanate, 30 g of pure water was added little by little at 25 ° C. with stirring to prepare a transparent liquid. Next, 6.53 g of strontium hydroxide octahydrate was added and dissolved at 25 ° C., and then diluted with ethanol to prepare 100 ml of solution A.
(Contact between liquid A and liquid B)
Under stirring, 100% of ethanol (C solution) was added dropwise with A solution and B solution at 25 ° C. for 15 minutes at the same time. After completion of dropping, the solution was aged at 25 ° C. for 15 minutes to obtain a precipitate.
The precipitate was filtered and dried at 80 ° C. to obtain Powder A. This powder A was observed with a scanning electron microscope (SEM), and the Sr / Ti molar ratio, the BET specific surface area, FT-IR, and the chlorine content by ion chromatography were measured. The molar ratio of Sr / Ti was determined by the fluorescent X-ray method. The results are shown in Table 1. A scanning electron micrograph (SEM) of powder A is shown in FIG. 1, and an infrared absorption spectrum is shown in FIG.

(Comparative Example 1)
A mixed solution prepared by dissolving 477.9 g of strontium chloride dihydrate and 444 g of titanium tetrachloride in 4100 ml of water was prepared, and this was designated as solution a. Next, 620 g of oxalic acid dihydrate was dissolved in 1500 ml of warm water at 70 ° C. to prepare an aqueous oxalic acid solution, which was designated as solution b. The liquid b was added to the liquid a over 120 minutes with stirring while maintaining the liquid at 70 ° C. After the addition was completed, the liquid was aged with stirring at 70 ° C. for 1 hour. After cooling, the precipitate was collected by filtration.
Next, the collected precipitate was repulped with 4.5 L of pure water three times and washed carefully, and then the precipitate was filtered and dried at 80 ° C. to obtain oxalate B.
In the same manner as in Example 1, this oxalate B was observed with a scanning electron microscope, and the Sr / Ti molar ratio, BET specific surface area, FT-IR, and chlorine content by ion chromatography were measured. The results are shown in Table 1. Moreover, the SEM photograph of oxalate B is shown in FIG. 3, and the infrared absorption spectrum is shown in FIG.

(Example 2)
5 g of the powder A obtained in Example 1 was baked in the air atmosphere at 800 ° C. for 6 hours, cooled, and pulverized to obtain a perovskite strontium titanate powder.
The obtained perovskite strontium titanate was evaluated for the Sr / Ti molar ratio, the average particle diameter, the BET specific surface area, the chlorine content by ion chromatography, and the presence or absence of residual strontium carbonate. Table 2 shows various physical properties of the obtained perovskite strontium titanate powder. In addition, the average particle diameter was obtained by SEM observation at a magnification of 50,000 times and an average value of 50 or more arbitrarily extracted particles. The presence or absence of residual strontium carbonate was determined by the presence or absence of a diffraction peak near 2θ = 25 ° by X-ray diffraction analysis. An SEM photograph is shown in FIG.

(Comparative Example 2)
5 g of oxalate B obtained in Comparative Example 1 was baked in the air atmosphere at 800 ° C. for 6 hours, cooled and pulverized to obtain a perovskite strontium titanate powder.
The obtained perovskite strontium titanate was evaluated for the Sr / Ti molar ratio, the average particle diameter, the BET specific surface area, the chlorine content by ion chromatography, and the presence or absence of residual strontium carbonate. Table 2 shows various physical properties of the obtained perovskite strontium titanate powder. An SEM photograph is shown in FIG.

(Example 3)
(Preparation of liquid B)
6.67 g of oxalic acid dihydrate was dissolved in 100 ml of ethanol at 25 ° C. to prepare a solution B.
(Preparation of solution A)
After adding 18.22 g of lactic acid to 8.56 g of tetra-n-butyl titanate, 30 g of pure water was added little by little at 25 ° C. with stirring to prepare a transparent liquid. Furthermore, 6.53 g of strontium hydroxide octahydrate was added and dissolved at 25 ° C., and then diluted with ethanol to make a 100 ml solution. Subsequently, with respect to this solution, barium hydroxide was dissolved at 25 ° C. so as to be 0.2% by mass with respect to the titanic acid composite oxide to be produced in terms of BaO, thereby preparing a solution A.
(Contact between liquid A and liquid B)
Under stirring, 100 parts of ethanol (liquid C) was added dropwise with liquid A and liquid B simultaneously at 25 ° C. for 5 minutes, and after completion of the dropwise addition, ripened at 25 ° C. for 15 minutes to obtain a precipitate. The precipitate was filtered and dried at 80 ° C. to obtain Powder C. This powder C was observed with a scanning electron microscope in the same manner as in Example 1, and the Sr / Ti molar ratio, BET specific surface area, FT-IR, chlorine content by ion chromatography, and Ba content were measured. The results are shown in Table 3. The molar ratio of Sr / Ti was determined by the fluorescent X-ray method, and the Ba content was determined by ICP.

  According to the present invention, a perovskite-type titanium composite oxide that is fine and has an X / Ti molar ratio of about 1 can be obtained, so that the capacity and dielectric constant of the multilayer ceramic capacitor can be increased.

2 is a SEM photograph of Example 1. 2 is an IR spectrum chart of Example 1. 2 is a SEM photograph of Comparative Example 1. 6 is an IR spectrum chart of Comparative Example 1. 2 is a SEM photograph of Example 2. 3 is a SEM photograph of Comparative Example 2.

Claims (13)

Ti element, at least one element selected from Sr, Ca and Mg (X element), lactic acid root, and succinic acid radical, BET specific surface area of 6 m ² / g or more, Titanium composite characterized in that the molar ratio of Ti element (X / Ti) is 0.98 to 1.02, and the peak top has infrared absorption spectrum peaks at 1120 to 1140 cm ⁻¹ and 1040 to 1060 cm ^−1. Salt powder.   The titanium composite salt powder contains a solution (solution A) containing Ti element, at least one element (X element) selected from Sr, Ca and Mg, and a lactic acid radical, and an oxalate radical. The titanium composite salt powder according to claim 1, wherein the titanium composite salt powder is obtained by contacting the solution (liquid B) in a solvent containing alcohol.   The titanium composite salt powder according to claim 1, wherein the chlorine content is 100 ppm or less.   Further, among rare earth elements, Li, Bi, Zn, Mn, Al, Ca, Sr, Ba, Co, Ni, Cr, Fe, Mg, Zr, Hf, V, Nb, Ta, Mo, W, Sn and Si The titanium composite salt powder according to any one of claims 1 to 3, comprising at least one subcomponent element selected from the group consisting of:   A solution (Liquid A) containing Ti element, at least one element (X element) selected from Sr, Ca and Mg, and a lactic acid radical, and a solution (Liquid B) containing an oxalate radical And a method for producing a titanium composite salt powder, wherein the contact is made in a solvent containing alcohol. The liquid A is a solution containing an aqueous solution or alcohol containing Ti element, at least one element selected from Sr, Ca and Mg, and a lactic acid radical, and the liquid B is an oxalic acid radical. A solution containing an alcohol containing
6. The method for producing a titanium composite salt powder according to claim 5, wherein the contact between the liquid A and the liquid B is performed by adding the liquid B to the liquid A or adding the liquid A to the liquid B. The liquid A is a solution containing an aqueous solution or alcohol containing Ti element, at least one element selected from Sr, Ca and Mg, and a lactic acid radical, and the liquid B is an oxalic acid root. An aqueous solution containing alcohol or a solution containing alcohol,
6. The contact between the liquid A and the liquid B is performed by adding the liquid B to the liquid C while adding the liquid A to a solvent containing alcohol (liquid C). Method for producing titanium composite salt powder.   The solution A is a solution prepared by adding at least one element source selected from Sr, Ca and Mg to a solution obtained by mixing a Ti element source, a lactic acid source and water. Item 7. The method for producing a titanium composite salt powder according to any one of Items 5 and 6.   The method for producing a titanium composite salt powder according to any one of claims 5 to 8, wherein the Ti element source of the liquid A is titanium alkoxide.   The method for producing a titanium composite salt powder according to any one of claims 5 to 9, wherein the X element source of the liquid A is a hydroxide.   The liquid A further includes rare earth elements, Li, Bi, Zn, Mn, Al, Ca, Sr, Ba, Co, Ni, Cr, Fe, Mg, Zr, Hf, V, Nb, Ta, Mo, W, The method for producing a titanium composite salt powder according to any one of claims 5 to 10, comprising at least one subcomponent element selected from Sn and Si.   A method for producing a perovskite-type titanium composite oxide powder, comprising firing the titanium composite salt powder according to any one of claims 1 to 4.   The method for producing a perovskite-type titanium composite oxide powder according to claim 12, wherein the firing temperature is 600 to 950 ° C.