JPH0124796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel lead-containing complex organometallic compound.

The lead-containing composite organometallic compound of the present invention can be used, for example, as a raw material for producing a lead-containing composite metal oxide.

Lead-containing composite metal compounds, such as lead titanate, lead zirconate, lead titanium zirconate (hereinafter referred to as "PZT"), and lanthanum-containing lead titanium zirconate (hereinafter referred to as "PLZT"), are known for their excellent dielectric properties. It is an important material for electronics due to its properties such as elasticity, piezoelectricity, and optical transparency.

Conventionally, these lead-containing composite metal oxides have been produced using a solid-phase method in which oxides of each metal component are used as starting materials and produced by high-temperature solid-phase reaction, and a mixed aqueous solution of nitrates of each metal component. ,
Solution methods are known in which they are produced by methods such as evaporation to dryness, freeze drying, and spray pyrolysis. However, the lead-containing composite metal oxide produced by the solid-phase method has a coarse particle size of several microns or more, and tends to have a wide particle size distribution, and easily entrains impurities during processes such as mixing and pulverization and sieving. In addition, it has the disadvantage that the composition deviates from the target metal atomic ratio, so it is suitable for electronics that are aiming for higher performance and smaller size.
In some cases, the requirements for ceramic materials cannot be met. As a method to compensate for the drawbacks of the solid phase method, a solution method has been proposed for producing lead-containing composite metal oxides by chemical and/or physical treatment of the solution.
Generally, it has the following characteristics.

(a) A lead-containing composite metal oxide having a particle size of 1 μm or less and a narrow particle size distribution can be obtained.

(b) It is easy to purify and remove impurities, and a highly pure product can be obtained.

(c) Homogeneous addition of additives is easy.

However, if we take PLZT, which has been studied relatively extensively as a lead-containing composite metal oxide, as an example,
Known solution methods have various deficiencies.

Chitabari Study Group Materials ××-116-799 (1971) and Electronics and Ceramics 9 (Summer issue)
(1978) 65, PLZT is
Oxyoxalate coprecipitate was obtained, and after drying the coprecipitate,
It is obtained as a powder by pre-calcining at a temperature of .degree. C. for 1 hour. However, the obtained PLZT
The particle size of the powder tends to become large, and there are defects that can only be obtained as a powder.

In the method described in Ceram. Bull. 53 (5) 421 (1974), PLZT dissolves lead nitrate, lanthanum nitrate, zirconium oxynitrate, and titanium isopropoxide in an aqueous nitric acid solution to obtain a homogeneous aqueous solution; It is obtained as a powder by coprecipitation, spray drying, freeze drying or evaporation to dryness, and then calcining at a temperature of 550 to 950°C for 16 to 32 hours. In this method, the titanium nitrate produced in the middle of the reaction is unstable, so it is difficult to store the above mixed aqueous solution, and large amounts of _NOx gas and nitric acid are generated in the post-treatment process of the mixed aqueous solution. Therefore, not only is the equipment subject to severe corrosion, but pollution control equipment must also be installed.

In the method described in Ferro-electrics 3 (1972) 269-280, lead monoxide is added to an isopropanol solution of titanium butoxide and zirconium butoxide, and while mixing in a blender, an aqueous solution of lanthanum acetate is added dropwise to perform hydrolysis. After drying the obtained slurry product, it was dried at a temperature of 500℃.
PLZT powder is obtained by calcining for 16 hours. The PLZT powder obtained by this method tends to have a large particle size, and since lead monoxide powder is used as a lead source, uneven distribution of lead is inevitable at the atomic level, and the resulting PLZT powder Characteristics as a material for electronics deteriorate.

In the method described in J.Ame.Ceram.Soc. 55 (11)541-544 (1972), isoamyloxide of lead,
Lanthanum isopropoxide, titanium isopropoxide, and zirconium tertiary amyloxide are dissolved in isopropanol, water is added dropwise to this mixed alkoxide solution to perform hydrolysis, and the resulting precipitate is dried and heated to a temperature of 500℃. PLZT powder is obtained by calcining for 1 hour. In this method, it is difficult to produce the raw materials lead and lanthanum alkoxides, and not only is the production cost high, but also other metal ions such as Na are inevitably mixed in as impurities during the production. Therefore, the obtained PLZT has poor characteristics as a material for electronics.

As a result of intensive research to improve the drawbacks of the above-mentioned method for producing lead-containing composite metal oxides using a known solution, the present inventors have discovered a novel lead-containing composite organic metal useful as a raw material for lead-containing metal oxides. discovered a compound and completed the present invention.

An object of the present invention is to provide a novel lead-containing composite organometallic compound.

The present invention has the following compositional formula [] Pb _(1-x)・La _x・M _(1-x/4)・O ₂・(OR) _y・(OCOR′) _z
...[] It is a lead-containing complex organometallic compound represented by the following.

The compound of the present invention comprises an organic titanium compound and/or an organic zirconium compound represented by the general formula [] M.(OR) ₄ ...[] and a general formula [] Pb.(OCOR') ₂ ...[] It is obtained by reacting the expressed organic lead compounds in the presence or absence of an organic lanthanum compound in an amount of 20 mol % or less of the organic lead compound.

In the production of the compounds of the present invention, in the organic titanium compounds and organic zirconium compounds represented by the general formula [] used as raw materials, R in the general formula [] is preferably the same or different monovalent hydrocarbon group. is a compound represented by different and similar alkyl groups having 1 to 8 carbon atoms, such as tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, diethoxy-diisopropoxytitanium, dibutoxy-diethoxytitanium , titanium alkoxides such as tetrakis(2-ethylhexoxy)titanium, and tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium,
These are zirconium alkoxides such as tetrabutoxyzirconium, diethoxy-diisopropoxyzirconium, diethoxy-dibutoxyzirconium, and tetrakis(2-ethylhexoxy)zirconium. Among these alkoxides, tetraisopropoxytitanium, tetrabutoxytitanium, tetrakis(2-ethylhexoxy)titanium, tetraisopropoxyzirconium, and tetrabutoxyzirconium are particularly preferred for use as raw materials because they are industrially produced and easily available. . When using both organic titanium compounds and organic zirconium compounds at the same time in the production of the compounds of the present invention, compounds with different substituents can be used. Considering recovery, it is preferable to use compounds having the same substituents. Organic lead compounds represented by the general formula [], which are other raw materials, are
R' is the same or different monovalent hydrocarbon groups, preferably carboxylic acids represented by different and the same alkyl groups having 1 to 8 carbon atoms, such as lead acetate, lead propionate, lead butyrate, etc.; When titanium and/or zirconium alkoxides are used as raw material compounds, it is desirable to use anhydrous organic lead compounds because the alkoxides are easily hydrolyzed.

In the production of the compound of the present invention, an organic lanthanum compound is used as the third raw material.
It can be added in an amount of mol% or less. The organic metal compounds to be added may be any solvent-soluble ones, but considering the recovery of alcohols and esters that are reaction products, it is preferable to use organic titanium compounds and/or organic zirconium compounds or organic lead compounds. Preference is given to using organic lanthanum compounds with identical substituents. Lead-containing complex organometallic compounds obtained by adding lanthanum carboxylates such as lanthanum acetate, lanthanum propionate, and lanthanum butyrate produce lanthanum-containing lead titanium zirconate, which is a lead-containing complex metal oxide with excellent transparency. (PLZT) can be obtained.

In the production of the compound of the present invention, the reaction may proceed in the presence or absence of an organic solvent, but preferably in the presence of an organic solvent at 100°C to 250°C, and more preferably, the reaction proceeds in the presence of an organic solvent. The process proceeds smoothly by carrying out the process under reflux of an organic solvent having a boiling point higher than that of the alcohols and esters while distilling off the produced alcohols and esters.

Examples of organic solvents include non-polar organic solvents such as toluene, xylene, diethylbenzene, tetralin, and decalin, as well as butanol, hexanol, and
- Any polar organic solvent such as ethylhexanol, butyl acetate, hexyl acetate, 2-ethylhexyl acetate, etc. can be used. This reaction is preferably carried out in the substantial absence of water in order to prevent hydrolysis of the raw organic titanium compound and/or organic zirconium compound and the resulting lead-containing complex organometallic compound. The reaction conditions for this reaction are preferably carried out in a dry atmosphere to avoid the above-mentioned hydrolysis, and the reaction temperature and reaction time vary depending on the type of raw materials, whether or not a solvent is used, and the type and amount of the organic solvent. Generally, the temperature is 50°C to 300°C, preferably 100°C to 250°C for 0.5 to 60 hours, preferably 1 to 15 hours, and more preferably 1 hour at a temperature of refluxing an organic solvent. ~8 hours.

In the production of the compounds of the present invention, if the reaction mixture contains solids other than the target product, unreacted raw materials in solution, by-products, organic solvents, etc., chemical or Utilizing differences in physical properties, the desired product can be isolated by combining unit operations such as filtration, centrifugation, distillation, concentration, and extraction.

The lead-containing complex organometallic compound represented by the composition formula [] produced by the above production method is:
Although it varies depending on the type of raw materials, blending ratio, type of organic solvent, reaction conditions, etc., the repeating constituent unit is the general formula [] [Pb・MO ₂・(OR) _x・(OCOR′) _y ] … [] ( Here, M, R and R' have the same meanings as above, x and y are 0, 1 or 2, and x+y is 2.
The main component is monomers or multimers (dimers to dodecamers under normal conditions).

In the case of the lead-containing complex organometallic compound according to the present invention, for example, a lead-containing complex organotitanium compound and a lead-containing complex organozirconium compound, the hydrolysis product of the lead-containing complex organometallic compound is dried at a temperature of 400°C or higher. lead titanate or lead zirconate by calcining the compound in an oxygen stream, or by directly thermally decomposing the compound in an oxygen stream at a temperature of 400℃ or higher
Produces fine crystals of 0.1~0.5μ.

In addition, whether an organic lanthanum compound is added to the lead-containing composite organic titanium compound and the lead-containing composite organic zirconium compound, or even if it is not added, the hydrolysis and firing are performed in the same manner as described above.
By thermal decomposition, lead-containing composite metal oxides such as lead titanium zirconate (PZT) and lanthanum-containing lead titanium zirconate (PLZT) are produced. In the composition, the composition ratio of titanium to zirconium can be set to any value between 0 and 100%.

Using an organic solvent solution of the compound according to the present invention,
A lead-containing composite metal oxide film can be formed on a heat-resistant substrate such as glass by a dipping method, a spray method, a spinner method, a roll coating method, an ultrasonic atomization method, or the like. Furthermore, depending on the type of organic solvent, it is possible to form a highly concentrated solution, so there is a great degree of freedom in selecting the next chemical and physical utilization means. Also, depending on the type of substituent, it may have some degree of hydrolyzability, so it is preferable to store it under conditions where it does not come into contact with moisture from the air or other sources.

The lead-containing composite organometallic compound of the present invention has the following characteristics.

(b) It can be manufactured by a simple method from relatively inexpensive and easily available raw materials, and is highly economical.

(b) Since it is soluble in organic solvents, fine powder can be produced by combining methods such as dipping method, spray method, spinner method, ultrasonic atomization method, nozzle blowing method, etc., and chemical means such as hydrolysis and thermal decomposition. Easily produce lead-containing composite metal oxides such as lead titanate, lead zirconate, lead titanium zirconate (PZT), lanthanum-containing lead titanium zirconate (PLZT), etc. in desired shapes such as lead titanate, thin film, fiber, etc. be able to.

(c) The metal atomic ratio is the same as the metal atomic ratio of the raw materials to be blended and is completely uniform, so
The metal atomic ratio in the lead-containing composite metal oxide obtained from this compound is the same as the metal atomic ratio of the raw materials to be blended, and is uniformly distributed at the atomic level, making it suitable for various electronic materials. It is possible to produce a lead-containing composite metal oxide that has significantly superior properties compared to conventional oxides.

(d) By hydrolysis and/or thermal decomposition, a lead-containing composite metal oxide in the form of extremely fine powder with a narrow particle size distribution can be produced.

(e) Since it is soluble in organic solvents, it has excellent compatibility and uniform mixability with various compounds. Therefore, sintering aids, additives for improving electrical properties, optical properties, etc. can be added homogeneously, and the properties of the resulting lead-containing composite metal oxide can be easily improved.

The present invention provides a lead-containing complex organometallic compound, and in particular, lanthanum-containing lead titanium zirconate (PLZT) can be easily produced by using the lead-containing complex organometallic compound of the present invention. This is an industrially extremely significant invention that can further advance the practical application of the lanthanum-containing titanium lead zirconate.

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited to the scope described in the following examples.

Example 1 Production of lead-containing organic titanium compound In a 100 ml four-necked flask equipped with a thermometer, reflux condenser, and stirrer, 16.3 gr of Pb (O・COCH ₂ CH ₃ ) ₂ was added.
(50 mmol), Ti(OC ₄ H ₉ ) ₄ , 17.1 gr (50 mmol), and 30 gr of decalin were charged, and the temperature was raised while stirring under N ₂ atmosphere. Butanol from the reaction temperature of about 130℃,
Butyl acetate began to distill out, and the reaction solution changed from its initial cloudy state to a yellow-brown homogeneous and transparent solution. Heat the reaction solution to the boiling point of decalin,
Butanol 4.4gr (60mmol), butyl acetate
8.0gr (69mmol) was distilled off, and then the solvent decalin was distilled off under reduced pressure to obtain 21.6gr of pale yellow solid. An acetyl group and a butyl group were confirmed in this product by IR analysis. From the elemental analysis values of Pb and Ti and the distilled amounts of butanol and butyl acetate, it was confirmed that the composition formula was Pb·TiO ₂ (OC ₄ H ₉ ) _1.4 (OCOC ₂ H ₅ ) _0.6 . Furthermore, the molecular weight was 1920, estimated to be a tetramer, by measuring the freezing point depression of a p-xylene solution.

[Elemental analysis value]

Calculated value Actual value Pb 48.8% 48.1% Ti 11.3% 11.1% Example 2 Production of high polymer Compound obtained in Example 1 10.8gr Decalin 15gr
The solution consisting of was heated to 220° C. under normal pressure to distill off most of the decalin, and then completely distilled off at 10 Torr and 100° C. to obtain 10.6 gr of a yellowish brown solid. From the results of IR analysis, elemental analysis of Pb and Ti, and analysis of butanol and butyl acetate in the distilled decalin, the composition formula is Pb・TiO ₂・(OC ₄ H ₉ ) _1.4・
(OCOC ₂ H ₅ ) was found to be _0.6 . The molecular weight was 6420 by freezing point depression measurement of paraxylene solution, and it was estimated to be a 16-mer.

Example 3 Production of Pb-Zr compound Pb (OCOC ₂ H ₅ ) ₂ 16.3gr, Zr as raw materials
The reaction was carried out in the same manner as in Example 1 except that (OC ₄ H ₉ ) ₄ 19.2gr (both 50 mmol) was used, and the composition formula was Pb.
A homogeneous and transparent decalin solution of ZrO ₂ (OC ₄ H ₉ ) _1.4 (OCOC ₂ H ₅ ) _0.6 was obtained, and then the solvent decalin was distilled off under reduced pressure to obtain 23.6 gr of pale yellow solid. IR analysis, Pb・
Elemental analysis of Zr, distilled butanol (5.2gr: 70mmol), butyl acetate (7.8gr:
67 mmol), the above composition was confirmed. The molecular weight of the p-xylene solution measured by freezing point depression was 2073, and it was estimated to be a tetramer.

[Elemental analysis value]

Calculated value Actual value Pb 44.3% 44.0% Zr 19.5% 19.3% Example 4 Production of Pb-Zr-Ti compound Pb・(OCOC ₂ H ₅ ) ₂ 13.0gr (40m
mol), Ti( _OC4H9 ) _46.8gr ( _20mmol ), Zr
The process was carried out in the same manner as in Example 1 except that (OC ₄ H ₉ ) ₄ 7.7gr (20 mmol) was used, and the average composition was Pb・Ti _0.5・
17.6 gr of pale yellow solid of Zr _{0.5.O 2.} (OC ₄ H ₉ ) _1.4 . (OCOC ₂ H ₅ ) _0.6 was obtained. The above average composition was confirmed from IR analysis, elemental analysis of Pb, Ti, and Zr, and the distilled amounts of butanol and butyl acetate. The molecular weight was 3767, and it was estimated to be an octamer.

[Elemental analysis value]

Calculated value Actual value Pb 47.7% 47.0% Ti 5.5% 5.4% Zr 10.5% 10.4% Example 5 Production of Pb-La-Zr-Ti compound In a 200 ml four-necked flask equipped with a thermometer, reflux condenser, and stirrer, As a raw material, Pb・
(OCOC ₂ H ₅ ) ₂ 29.9gr (92mmol), La
(OCOC ₂ H ₅ ) ₃ 2.5gr (8mmol), Ti
(OC ₄ H ₉ ) ₄ 11.7gr (34.3mmol), and Zr
(OC ₄ H ₉ ) ₄ 24.4 gr (63.7 mmol) was charged, 50 gr of decalin was added as a solvent, and the following treatment was carried out in the same manner as in Example 1 to obtain 44.7 gr of pale yellow solid. From IR analysis, elemental analysis, and distillation amounts of butanol and butyl acetate, Pb _0.92 , La _0.08 , Ti _0.343 , Zr _0.637 ,
It was confirmed that the average composition was (OC ₄ H ₉ ) _1.5・(OCOC ₂ H ₅ ) _0.5 . The average molecular weight was 1011, and it was estimated that it was a dimer.

[Elemental analysis value]

Calculated value Actual value Pb 42.6% 42.2% La 2.5% 2.4% Ti 3.7% 3.6% Zr 13.0% 12.8% Example 6 Production of PLZT (hydrolysis) 2.5 gr of the composition obtained in Example 5 was dissolved in 60 gr of xylene. Heat and maintain at a temperature of 90-95℃, water 180mg
was added dropwise using a microsyringe over 2 hours with vigorous stirring. After the generated precipitate was filtered off, it was dried at 140°C under reduced pressure, and then heated at 400°C for 1 hour to obtain 1.8g of PLZT powder. (Yield 99
%) The filtered filtrate did not contain any metal components.

As a result of X-ray diffraction, PLZT powder has a cubic crystal structure (a=
4.095), and it was confirmed by SEM observation that it was 0.1μ fine particles and their aggregates.

Example 7 Production of PLZT (pyrolysis) 6.8gr of the composition obtained in Example 5 was heated to 630g under air circulation.
It was calcined for 2.5 hours at a temperature of ℃ to obtain 4.8gr of PLZT powder. As a result of X-ray diffraction, it is a cubic crystal (a = 4.095),
As a result of SEM observation, fine particles of 0.2 to 0.4 μ were aggregated 1
It was an aggregate of ~2μ.

Example 8 Production of PLZT thin film 6.9gr of the composition obtained in Example 5 was mixed with 95gr of butanol.
to prepare a 5WT% solution in terms of PLZT. Add to this solution 30×50mmd=3mm under _N2 atmosphere.
After about 1 minute, the quartz glass was immersed in the solution, and after about 1 minute, it was pulled out of the solution at a constant speed of 3 cm/min. After the solvent was sufficiently evaporated under N ₂ , it was dried in air at 100°C for 1 hour, and then heated at 900°C in an electric furnace. , 3Hr sintered transparent PLZT
A thin film was obtained.

Claims (1)

[Claims] 1 Compositional formula [] Pb _(1-x)・La _x・M _(1-x/4)・O ₂・(OR) _y・(OCOR′) _z
...[] [Here, M is Ti and/or Zr, R and R' are different or similar monovalent hydrocarbon groups, 0≦X≦0.2 y+Z=2 Z≠0. ] A lead-containing complex organometallic compound represented by 2. The lead-containing composite organometallic compound according to claim 1, wherein R and R' are the same or different alkyl groups having 1 to 8 carbon atoms.