JP4821974B2 - Method for producing composition for forming lead-containing composite oxide - Google Patents

Description

The present invention, lead-containing composite oxide, for example, relates to the production how lead-containing composite oxide forming composition having excellent dispersion stability used to form a ferroelectric thin film.

  Ferroelectric thin films containing crystals typified by lead zirconate titanate (PZT) have spontaneous polarization, high dielectric constant, electro-optic effect, piezoelectric effect, pyroelectric effect, etc. It is applied to a wide range of device development. As a method for forming such a ferroelectric thin film, for example, a MOD (Metal Organic Deposition) method, a sol-gel method, a CVD (Chemical Vapor Deposition) method, a sputtering method, and the like are known. The method and the sol-gel method have an advantage that a ferroelectric thin film can be easily formed at a relatively low cost.

  When a ferroelectric thin film is formed by the MOD method, generally, a colloidal solution obtained by dissolving an organometallic compound such as a metal alkoxide or an acetylacetonate complex in alcohol and adding alkanolamine or the like to this is coated. After coating on the object, it is dried and fired to form a film. On the other hand, in the case of forming a film by the sol-gel method, a colloidal solution obtained by dissolving an organometallic compound in a solvent such as alcohol and hydrolyzing it is applied onto an object, and then dried and fired. By doing so, it forms into a film (for example, refer to patent documents 1).

  Such a colloidal solution has a problem that when stored for a long period of time, the sol aggregates and precipitates, resulting in poor storage stability. In particular, when an acetylacetonate complex is used as the organometallic compound, the acetylacetonate complex is difficult to be decomposed and is likely to be precipitated, resulting in poor dispersion stability. When precipitation occurs in this way, the composition of the ferroelectric thin film forming composition fluctuates, and this causes the film components of the ferroelectric thin film to be dispersed unevenly, resulting in a piezoelectric element having a ferroelectric thin film. The piezoelectric characteristics of the fluctuate. Furthermore, in a liquid ejecting head that includes a piezoelectric element as an actuator device, such a variation in piezoelectric characteristics of the piezoelectric element causes variations in liquid ejection characteristics. In addition, the problem that the dispersion stability of the acetylacetonate complex mentioned above is bad is not only in the composition for forming a ferroelectric thin film but also in the composition for forming a lead-containing composite oxide containing the acetylacetonate complex. Exists.

Japanese Patent Laid-Open No. 06-5946

The present invention has been made in view of such circumstances, to provide a manufacturing how lead-containing composite oxide forming composition can be dispersion stability of the acetylacetonato complex is maintained over a long term good storage stability This is the issue.

According to a first aspect of the present invention, lead acetate as a raw material for lead oxide, titanium alkoxide and zirconium acetylacetonate as raw materials for metal oxides other than lead, and acetic acid are mixed with acetic acid / zirconium acetylacetonate ( No heating so that the molar ratio) is greater than 2 and Pb: Zr: Ti = 1.0 to 1.2: 0.51 to 0.56: 0.44 to 0.49 (molar ratio). The composition for forming a lead-containing composite oxide comprising a colloidal solution is obtained by mixing in a method for producing a composition for forming a lead-containing composite oxide.
In the first embodiment, a composition for forming a lead-containing composite oxide having excellent dispersion stability and excellent storage stability of zirconium acetylacetonate, which is an acetylacetonate complex , is produced by a relatively easy method. Can do.

According to a second aspect of the present invention, the lead-containing composite oxide forming composition according to the first aspect is characterized in that the acetic acid and the zirconium acetylacetonate are mixed after the lead acetate is mixed in a solvent. It is in the manufacturing method of a thing.
In the second embodiment, the dispersion stability of zirconium acetylacetonate, which is an acetylacetonate complex , is improved by the added acetic acid.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
The composition for forming a lead-containing composite oxide of the present invention is a colloidal solution (sol) used to form a lead-containing composite oxide such as a ferroelectric thin film, specifically, as a raw material for lead oxide. Lead acetate, a metal alkoxide and acetylacetonate complex as a raw material for metal oxides other than lead, and a colloidal solution containing acetic acid, the molar ratio of acetic acid and acetylacetonate complex in the colloidal solution, That is, the acetic acid / acetylacetonate complex (molar ratio) is larger than 2. Here, “acetic acid” in the acetic acid / acetylacetonate complex (molar ratio) means acetic acid contained in the colloidal solution, that is, acetic acid liberated from acetic acid added as a raw material and lead acetate. In the composition for forming a lead-containing composite oxide of the present invention, by adding acetic acid, acetic acid binds to the acetylacetonate complex with a weak interaction, so the dispersibility stability of the acetylacetonate complex is significantly improved. In addition, the storage stability of the composition for forming a lead-containing composite oxide is improved. As described above, the composition for forming a lead-containing composite oxide of the present invention is excellent in dispersion stability and storage stability. Therefore, when a lead-containing composite oxide is formed using the composition, the metal component has a substantially uniform composite oxidation. You can get things. The acetic acid / acetylacetonate complex (molar ratio) is more preferably 4 or more. In the present invention, the content of acetic acid is not particularly limited in terms of enhancing the dispersion stability of the acetylacetonate complex, but the lead-containing complex oxidation with respect to the conditions of the complex oxide formation process such as coating, drying and firing. It is preferable to consider the viscosity of the product forming composition.

  Examples of the metal alkoxide include titanium alkoxide and titanium isopropoxide. Examples of the acetylacetonate complex include zirconium acetylacetonate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, and zirconium bisacetylacetonate. The metal alkoxide is preferably titanium alkoxide and the acetylacetonate complex is preferably zirconium acetylacetonate.

  The molar ratio of metal to lead in the metal alkoxide or acetylacetonate complex is not particularly limited. For example, in the case of a composition for forming lead zirconate titanate (PZT), Pb: Zr: Ti = 1.0 to 1 It is preferable to contain lead acetate, a metal alkoxide, and a metal acetylacetonate so that it may become 0.2: 0.51-0.56: 0.44-0.49 (molar ratio).

  Examples of the solvent contained in the composition for forming a lead-containing composite oxide of the present invention include alcohol solvents. Examples of the alcohol solvent include 2-n-butoxy alcohol, n-pentyl alcohol, 2-phenylethanol, 2-phenoxyethanol, methoxyethanol, ethylene glycol monoacetate, triethylene glycol, trimethylene glycol, propylene glycol, and neopentyl. Examples thereof include glycol and isoamyl acetate, and these solvents may be used alone or in combination.

  The composition for forming a lead-containing composite oxide of the present invention may further contain an alkanolamine. When the alkanolamine is contained, the dispersion stability of the metal alkoxide and lead acetate can be improved. Examples of the alkanolamine include monoethanolamine and diethanolamine. These alkanolamines may be used alone or in combination.

  In addition, if necessary, as a stabilizer for stabilizing the lead-containing composite oxide and for preventing the occurrence of cracks in the formed ferroelectric thin film, for example, polyethylene glycol or the like as an additive You may add and you may add a thickener etc. as another additive.

  The composition for forming a lead-containing composite oxide of the present invention can be suitably applied to the MOD method. The MOD (Metal Organic Deposition) method does not cause a gelation reaction (hydrolysis reaction), but simply applies a solution of an organic metal material, such as a metal alkoxide or an acetylacetonate complex, is dried, and heat-treated. A method for obtaining a film or the like. Since the composition for forming a lead-containing composite oxide of the present invention can be applied to the MOD method, a lead-containing composite oxide such as a ferroelectric thin film can be easily formed at a relatively low cost.

Hereinafter, the lead-containing composite post-oxide forming composition of the present invention will be described in more detail based on the following test examples.
(Test example) Dispersion stability of Zr acetylacetonate 27.5 g of zirconium acetylacetonate was added to 118 g of 2-n-butoxyethanol (CH ₃ (CH ₂ ) ₃ OCH ₂ CH ₂ OH), and zirconium acetylacetonate ( A solution having a concentration of Zr (CH ₃ COCHCOCH ₃ ) ₄ ) of 0.3 mol / L was prepared. To this solution, acetic acid (CH ₃ COOH), water (H ₂ O) and isopropyl alcohol (IPA) were mixed so as to have the number of moles shown in Table 1 below with respect to 1 mole of zirconium acetylacetonate. All the above operations were performed at room temperature. Each mixed solution was put in a container and stored at room temperature for 10 days in an opened state, and the presence or absence of precipitation was observed. The results are shown in Table 1. In addition, IPA derived from water derived from lead acetate trihydrate (Pb (CH ₃ COO) ₂ .3H ₂ O) and titanium tetraisopropoxide (Ti ((CH ₃ ) ₂ CHO) ₄ ). Assuming water and IPA were mixed in the number of moles shown in Table 1. Specifically, Pb: Zr: Ti = 1.2: 0.55: 0.45 (molar ratio) derived from lead acetate trihydrate produced when producing a composition for forming lead zirconate titanate Samples 1 and 4 are a mixture of 6.6 moles of water and 3.2 moles of IPA derived from titanium tetraisopropoxide, and the other samples have the same amount or more than Samples 1 and 4. Small amounts were mixed respectively.

  As shown in Table 1, in samples 1 to 3, in which the acetic acid / acetylacetonate complex (molar ratio) is 2, zirconium acetylacetonate and the like are precipitated after 10 days, and the amount of water added is particularly reduced. Therefore, the amount of precipitation increased (Samples 2 and 3). On the other hand, Samples 4 to 8 having an acetic acid / acetylacetonate complex (molar ratio) of 4 have no precipitation even after 10 days, and samples 5 and 6 with a reduced water content and IPA content are reduced. The reduced samples 7 and 8 also had very good dispersion stability.

  From this test result, in the lead-containing composite oxide forming composition, when the acetic acid / acetylacetonate complex (molar ratio) is greater than 2, the dispersion stability of zirconium acetylacetonate is good and the composition is stored for a long time. However, since precipitation did not occur, it was found that the zirconium acetylacetonate had very excellent dispersion stability and storage stability. In addition, when the acetic acid / acetylacetonate complex (molar ratio) is larger than 2, even if water or IPA decreases during the preparation or storage of the lead-containing composite oxide forming composition, regardless of water or IPA It was found that the storage stability was excellent.

  Such a composition for forming a lead-containing composite oxide of the present invention comprises lead acetate as a raw material for lead oxide, a metal alkoxide and acetylacetonate complex as a raw material for metal oxides other than lead, and acetic acid. By mixing so that the acetic acid / acetylacetonate complex (molar ratio) is larger than 2, a colloidal solution can be obtained. Moreover, you may mix alkanolamine. By adding acetic acid, acetic acid binds to the acetylacetonate complex with a weak interaction, so that the dispersion stability of the acetylacetonate complex is remarkably improved, and the lead-containing composite oxide forming composition is preserved. Stability is improved. Thus, the dispersion stability of the acetylacetonate complex is relatively easy by adding acetic acid to the metal oxide raw material and blending so that the acetic acid / acetylacetonate complex (molar ratio) is greater than 2. Can be produced, and a composition for forming a lead-containing composite oxide having excellent storage stability can be produced. Here, since lead acetate is also mixed in the composition for forming a lead-containing composite oxide as described above, taking into account the acetic acid liberated from this lead acetate, for example, acetic acid as a raw material for the acetylacetonate complex By mixing 2 moles or more, the dispersion stability of the acetylacetonate complex is improved, and the storage stability of the produced lead-containing composite oxide forming composition is improved. In addition, in the composition for forming a lead-containing composite oxide of the present invention, by adding acetic acid, the dispersion stability of the metal acetylacetonate complex is improved. Therefore, in a solvent such as an alcohol solvent without heating. Can be distributed. Therefore, the composition for forming a lead-containing composite oxide of the present invention can be produced without heating, and has an advantage that no unwanted reaction occurs and impurities are not mixed.

  Here, the order of mixing the components is preferably that acetic acid and an acetylacetonate complex are mixed after mixing lead acetate in a solvent and dispersing lead acetate in the solvent. Specifically, for example, a method of mixing a metal alkoxide with a solvent, mixing an alkanolamine as necessary, mixing lead acetate with this mixed solution, and then mixing an acetylacetonate complex and acetic acid. Can do. The acetic acid may be added before or after the addition of the acetylacetonate complex. Also, alkanolamine may be added before or after the addition of acetic acid, but it is preferable to add alkanolamine before the addition of acetic acid, because the dispersion stability of the acetylacetonate complex tends to be good. is there.

  Moreover, a ferroelectric thin film can be formed with the composition for forming a lead-containing composite oxide of the present invention. The composition for forming a lead-containing composite oxide of the present invention is excellent in dispersion stability of the acetylacetonate complex and can maintain the storage stability of the composition for forming a lead-containing composite oxide over a long period of time. In the ferroelectric thin film formed using this, the film components are dispersed substantially uniformly, that is, the film quality of the ferroelectric thin film becomes substantially uniform, and stable piezoelectric characteristics can be exhibited.

Here, the ferroelectric thin film formed by the composition for forming a lead-containing composite oxide of the present invention is, for example, a ferroelectric material (piezoelectric material) such as lead zirconate titanate (PZT) or niobium. In addition, a crystal such as a relaxor ferroelectric substance to which a metal such as nickel, magnesium, bismuth or ytterbium is added. As the composition, for example, PbTiO ₃ (PT), PbZrO ₃ (PZ), Pb (Zr _x Ti _1-x ) O ₃ (PZT), Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Pb (Zn _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PZN-PT), Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PNN-PT), _{Pb (In 1/2 Nb 1/2) O} 3 -PbTiO 3 (PIN-PT), Pb (Sc 1/2 Ta 1/2) O 3 -PbTiO 3 (PST-PT), Pb (Sc 1/2 _{nb 1/2) O 3 -PbTiO 3 (} PSN-PT), biScO 3 -PbTiO 3 (BS-PT), BiYbO 3 -PbTiO 3 (BY-PT) and the like.

  Such a ferroelectric thin film can be produced by applying the composition for forming a lead-containing composite oxide of the present invention on an object, drying it and firing it. In the coating step of applying the lead-containing composite oxide forming composition on the object, dry inert gas is introduced at a predetermined flow rate into the tank in which the lead-containing composite oxide forming composition is stored. Preferably, the composition for forming a lead-containing composite oxide is transported to a nozzle connected to a tank, and the composition for forming a lead-containing composite oxide is dropped onto an object to be rotated from the nozzle. Thereby, a precursor film of a ferroelectric thin film in which film components are dispersed substantially uniformly can be manufactured relatively easily.

  The above-described composition for forming a lead-containing composite oxide according to the present invention and the ferroelectric thin film formed by using this composition for forming a lead-containing composite oxide should be applied to a wide range of device development. The application is not particularly limited, but for example, microactuator, filter, delay line, lead selector, tuning fork oscillator, tuning fork clock, transceiver, piezoelectric pickup, piezoelectric earphone, piezoelectric microphone, SAW filter, RF modulator, resonance It can be applied to a child, a delay element, a multi-strip coupler, a piezoelectric accelerometer, a piezoelectric speaker and the like.

(Embodiment 2)
Hereinafter, an ink jet recording head which is an example of a liquid jet head in which the composition for forming a lead-containing composite oxide of the present invention is applied to a piezoelectric actuator will be described in detail with reference to FIGS. FIG. 1 is an exploded perspective view illustrating an outline of an ink jet recording head which is an example of a liquid ejecting head, and FIG. 2 is a plan view and a cross-sectional view taken along line AA ′ of FIG. As shown in FIGS. 1 and 2, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation (110) in the present embodiment, and silicon oxide (SiO ₂₎ previously formed by thermal oxidation on one surface thereof. ), And an elastic film 50 having a thickness of 0.5 to 2 μm is formed.

  The flow path forming substrate 10 is provided with a plurality of pressure generating chambers 12 partitioned by a plurality of partition walls 11 by anisotropically etching a silicon single crystal substrate from one side thereof. In addition, on the outside of one end portion in the direction (longitudinal direction) orthogonal to the direction in which the pressure generating chambers 12 are arranged (width direction), a communication portion 13 that communicates with a reservoir portion 32 of a protective substrate 30 described later. Is formed. The communication portion 13 is in communication with each other at one end in the longitudinal direction of each pressure generating chamber 12 via an ink supply path 14.

  A mask film 51 for forming the pressure generating chamber 12 is provided on the opening surface side of the flow path forming substrate 10, and the ink supply path 14 of each pressure generating chamber 12 is provided on the mask film 51. A nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end on the opposite side is fixed with an adhesive, a heat welding film, or the like.

  On the other hand, an insulating film 55 having a thickness of, for example, about 0.4 μm is formed on the elastic film 50 opposite to the opening surface of the flow path forming substrate 10. For example, a lower electrode film 60 having a thickness of about 0.2 μm, a ferroelectric thin film (piezoelectric layer) 70 having a thickness of about 1 μm, and a thickness of about 0.05 μm, for example. The piezoelectric film 300 is formed by laminating the electrode film 80 by a process described later. Here, the ferroelectric thin film 70 of the present embodiment is a colloid containing lead acetate as a lead oxide raw material, a metal alkoxide and acetylacetonate complex as a raw material of a metal oxide other than lead, and acetic acid. It is formed by the MOD method using the composition for forming a lead-containing composite oxide of the present invention, which comprises a solution and has an acetic acid / acetylacetonate complex (molar ratio) greater than 2.

  The piezoelectric element 300 refers to a portion including the lower electrode film 60, the ferroelectric thin film 70, and the upper electrode film 80. In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the ferroelectric thin film 70 are patterned for each pressure generating chamber 12. In this case, a portion that is composed of any one of the patterned electrodes and the ferroelectric thin film 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In any case, a piezoelectric active part is formed for each pressure generating chamber 12. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the present embodiment, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm. Only the lower electrode film 60 may be provided as a vibration plate.

  Further, on the piezoelectric element 300 side of the flow path forming substrate 10, a protective substrate 30 having a piezoelectric element holding portion 31 capable of ensuring a space that does not hinder the movement in a region facing the piezoelectric element 300 is interposed via an adhesive. Are joined. Since the piezoelectric element 300 is formed in the piezoelectric element holding part 31, it is protected in a state hardly affected by the external environment. In addition, as for the piezoelectric element holding | maintenance part 31, the space may be sealed and does not need to be sealed.

  Further, the protective substrate 30 is provided with a reservoir portion 32 that constitutes at least a part of the reservoir 100 serving as a common ink chamber for the pressure generating chambers 12, and the reservoir portion 32 is configured as described above. The reservoir 100 is configured to communicate with the ten communication portions 13 and serve as a common ink chamber for the pressure generation chambers 12. A through hole 33 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 31 and the reservoir portion 32 of the protective substrate 30. The lead electrode 90 drawn from each piezoelectric element 300 is exposed in the through hole 33 in the vicinity of its end.

  Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. The fixing plate 42 is made of a hard material such as metal. Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of this embodiment, ink is taken in from an external ink supply means (not shown), filled with ink from the reservoir 100 to the nozzle opening 21, and then driven according to a drive signal from a drive IC (not shown). Then, a driving voltage is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12, and the elastic film 50, the insulator film 55, the lower electrode film 60, and the ferroelectric thin film 70 are bent. By deforming, the pressure in each pressure generating chamber 12 is increased and ink droplets are ejected from the nozzle openings 21.

  In the ink jet recording head of the present embodiment described above, the ferroelectric thin film 70 includes lead acetate as a lead oxide raw material, a metal alkoxide and acetylacetonate complex as a raw material of a metal oxide other than lead, and acetic acid. A lead-containing composite oxide-forming composition having an acetic acid / acetylacetonate complex (molar ratio) greater than 2, that is, a composition excellent in dispersion stability and storage stability. Therefore, the film components of the ferroelectric thin film 70 are dispersed substantially uniformly, and the film quality of the ferroelectric thin film 70 becomes substantially uniform. Therefore, the ink ejection characteristics of the head can be stabilized and the reliability of the head can be improved.

  In the present embodiment, an ink jet recording head that discharges ink as an example of a liquid ejecting head has been described as an example. However, the present invention is not limited to this. For example, a recording head used in an image recording apparatus such as a printer, a liquid crystal display, or the like. Examples include color material ejection heads used in the production of color filters, electrode material ejection heads used in electrode formation for organic EL displays, FEDs (surface emitting displays), and bioorganic matter ejection heads used in biochip production. .

FIG. 6 is an exploded perspective view illustrating an outline of a recording head according to a second embodiment. FIG. 6A is a plan view of a recording head according to a second embodiment, and FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Piezoelectric element holding | maintenance part, 32 Reservoir part, 40 Compliance board | substrate, 60 Lower electrode film, 70 Ferroelectric thin film (piezoelectric body) Layer), 80 upper electrode film, 90 lead electrode, 100 reservoir, 300 piezoelectric element

Claims (2)

Lead acetate as a raw material for lead oxide, titanium alkoxide and zirconium acetylacetonate as raw materials for oxides of metals other than lead, and acetic acid, acetic acid / zirconium acetylacetonate (molar ratio) is greater than 2 and Pb: Zr: Ti = 1.0 to 1.2: 0.51 to 0.56: 0.44 to 0.49 (molar ratio). By mixing without heating, a colloidal solution is used. A method for producing a composition for forming a lead-containing composite oxide, comprising obtaining a composition for forming a lead-containing composite oxide. After mixing the lead acetate in a solvent, the production method of the lead-containing composite oxide forming composition according to claim 1, characterized in that mixing the acid and the zirconium acetylacetonate.

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