JP6480844B2 - Perovskite black powder, method for producing the same, and resin composition using the same - Google Patents

Description

  The present invention relates to a perovskite black powder, a method for producing the same, and a resin composition. More specifically, a special inorganic material is prepared by using a special wet precipitation mixing method, so that it has a perovskite type or a similar flexible crystal structure, and has not been prepared by a conventional wet method. In addition, since the primary particle size is a crystal grown to 1 μm or more, it has excellent wettability with respect to the resin, and depending on the forming component, it exhibits high adsorptivity to various components such as oxygen, and is high. The present invention relates to a technique for providing a perovskite black powder prepared by wet precipitation and capable of realizing various functions such as conductivity.

  Conventionally, a composite oxide black powder that can replace carbon black or the like useful as a black pigment or a conductive material has been developed. For example, as a composite oxide having a perovskite type crystal structure made of an inorganic material, Patent Document 1 proposes a composite oxide black pigment containing rare earth elements, alkaline earth metals and iron as constituent elements. Therefore, various properties such as hue, coloring power, dispersibility, heat resistance, water resistance, chemical resistance and the like that can be used as a colorant can be compared with conventional black pigments such as carbon black. Patent Document 2 proposes a strontium iron oxide particle powder exhibiting high blackness and excellent heat resistance. Further, Patent Document 3 proposes a black particle powder made of strontium iron oxide having excellent blackness and chemical resistance.

  As a method for producing an inorganic material used in this field, a substance containing a constituent metal element such as an oxide, carbonate, hydroxide or the like is uniformly pulverized and mixed in a predetermined stoichiometric amount, dry or wet. In general, the desired composite oxide is obtained by firing. More specifically, solid raw material compounds are pulverized and mixed, or wet mixed using a mixed solution containing raw metal, and these mixtures are fired to obtain a composite oxide. On the other hand, in the wet precipitation method, a mixed aqueous solution of a salt containing raw material elements and an aqueous alkaline solution are added to a precipitation bath, and a wet precipitation mixture obtained by precipitating a hydroxide precipitate is filtered, washed with water, and dried. The desired composite oxide is obtained by firing the precursor obtained in this manner. In the examples of Patent Documents 1 and 3 described above, black powders composed of complex oxides are obtained by using a dry process or a wet precipitation process without limiting the process. In Patent Document 2 described above, the above complex oxide is obtained using wet grinding.

Japanese Patent No. 4056826 Japanese Patent No. 4399886 Japanese Patent No. 4223784

  Under the circumstances described above, as a result of intensive studies, the present inventors obtained a composite oxide composed of a desired inorganic material, in addition to appropriately selecting the constituent elements thereof, in the dry process and the wet precipitation process. The characteristics of the resulting composite oxide are greatly different, for example, we found that it affects the properties of the composite oxide such as wettability to the resin, oxygen adsorption amount and conductivity. is there. More specifically, for example, in a system containing an alkaline earth metal element, a composite oxide obtained by a dry process causes melting of an alkaline earth metal in addition to sintering by firing at a high temperature. Easy, particles tend to be hard and coarse. In this case, a composite oxide material having a desired particle diameter can be obtained by pulverization. However, according to the study by the present inventors, a powdered mixed material of constituent components is fired to obtain a sintered body. For this reason, there are problems that the particle diameters are irregular or too large depending on the application, or are too hard to handle in some cases. Moreover, the particle | grains obtained by the dry-type manufacturing method had the subject that it was inferior in the wettability with respect to resin required when using it disperse | distributing to resin.

  On the other hand, the composite oxide obtained by the wet precipitation method is generally highly reactive, so that it can be fired at a lower temperature and is softer and has better wettability to the resin than particles obtained by the dry method. However, according to the study by the present inventors, the composite oxide obtained by the conventional wet precipitation method has a tendency that the particle diameter tends to be too fine, and even if it is large, the primary particle diameter is as small as about 0.5 μm or less. In some applications, such as when dispersed in a resin and used as a colorant, particles of several μm, particularly more than 3 μm, are required, and there is a problem that they cannot be used. Further, according to the study by the present inventors, in the conventional wet precipitation method, precipitated particles are reduced and the precipitation rate is increased, so that they are easily aggregated, and the primary particles are large in the precursor before firing. It turns out that it is easy to become. Further, in the conventional wet precipitation method, the size of the precipitate of each constituent component is likely to be uneven, the reactivity when fired is inferior, and even if large particles can be formed by firing, the purpose of the present invention is It was found that such crystals could not be obtained.

  A complex oxide having a perovskite crystal structure made of an inorganic material has characteristics that it is easy to exhibit various functions such as conductivity and adsorption of various components due to its flexible crystal structure. In order to fully exhibit its high functionality and to be used in a wide range of applications, its characteristics are particularly high when it is dispersed in a resin when used as pellets, dispersions, or resin compositions. We have come to realize that it is necessary to develop a technology capable of providing a composite oxide material having a structure that develops in a better state.

  Accordingly, an object of the present invention is to provide a composite oxide having a perovskite type crystal structure made of an inorganic material containing three or more constituent elements, softer than a powder obtained by a dry process, and having a conventional wet precipitation. An object of the present invention is to provide a perovskite black powder which is a material having excellent functionality, in which the primary particle size is significantly larger than that obtained by the production method, and the primary particle size is 1 μm or more.

  The above-described problems of the prior art are solved by the following present invention. That is, the present invention includes, as a constituent element, a rare earth element and / or an alkaline earth metal element, and any element selected from Cr, Mn, and an element of the periodic table group 8 element, and at least three kinds There is provided a perovskite black powder characterized in that it is a composite oxide having a perovskite-type or similar flexible crystal structure composed of these elements and having a primary particle size of 1 μm or more.

  Preferred forms of the perovskite black powder include the following. The primary particle size is 2 μm or more and 10 μm or less; the rare earth element is lanthanum, the alkaline earth metal element is strontium, and the group 8 element of the periodic table is iron, cobalt, and manganese. And the alkaline earth metal element is strontium, and the strontium content is 90 to 100% of the content in the stoichiometric composition.

  As another embodiment, the present invention provides a method for producing any one of the above perovskite black powders, comprising: a mixed salt aqueous solution of at least three or more constituent element salts; and an alkaline aqueous solution that is a precipitation aqueous solution. The precipitate mixture is added dropwise to precipitation water at the same time to synthesize a precipitate mixture under conditions of pH 6 to less than pH 8, and the resulting precipitate mixture is filtered, washed with water, and dried to obtain a black powder precursor. The present invention provides a method for producing a perovskite black powder characterized in that a composite oxide having a primary particle size of 1 μm or more is obtained by firing the body.

  The following are mentioned as a preferable form of the manufacturing method of the said perovskite type black powder. The pH is 6.5 or more and 7.5 or less; the temperature at the time of synthesizing the precipitation mixture is in the range of room temperature to 70 ° C .; the firing temperature of the precursor is 900 ° C. to 1300 It is ° C.

  As another embodiment, the present invention provides a resin composition characterized in that any of the above perovskite black powders is dispersed and contained in a resin.

  The perovskite black powder of the present invention achieves precipitation mixing by microprecipitation by wet-precipitation mixing of at least three kinds of constituent elements under specific conditions, and provides a good precursor of black powder. Since it was prepared by increasing the reactivity during firing and firing this precipitate mixture, the following effects can be exhibited. That is, the perovskite-based black powder of the present invention has a characteristic that the conventional oxide material having a perovskite-type crystal structure exhibits, for example, the characteristics such as conductivity and adsorption to oxygen components, which cannot be achieved by the conventional material. It can be made to exhibit high performance, and is softer than the material obtained by dry mixing and preparing similar constituent elements, and exhibits good wettability to the resin.For example, when dispersed in a resin It can be mixed and dispersed satisfactorily and can suppress wear on the mixing / dispersing device, etc., so that it is extremely useful as a black pigment that can be substituted for widely used carbon black. Specifically, the perovskite black powder of the present invention can be used as a colorant for paints, inks, and plastics, for example, as a black pigment. Furthermore, the perovskite black powder of the present invention can be used as various conductive materials such as electrolytes and air electrodes in fuel cells, for example, due to its high electrical conductivity, depending on the constituent elements used. In addition, as an oxygen storage material utilizing the property of storing oxygen in the crystal lattice, it can be expected to be applied to, for example, oxygen supply devices, nitrogen supply devices, oxygen production devices, pure nitrogen production devices, oxidation catalysts, etc. It is a material with excellent functionality that can be used in the field.

It is an electron micrograph of the Sr-Co-Fe perovskite black powder synthesized by the wet precipitation method of Example 1 of the present invention.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In the present invention, first, constituent metal elements are limited to specific ones. As described above, a composite oxide that is an inorganic material and has a perovskite-type crystal structure easily exhibits various functions such as conductivity and adsorption of various components from its flexible crystal structure. Among the constituent elements having such a crystal structure, selected from rare earth elements and / or alkaline earth metal elements and Cr, Mn of the fourth period of the element periodic table and transition metals of Group 8 elements of the element periodic table The main component is at least three elements including any element. More preferably, in the above, the rare earth element is lanthanum, the alkaline earth metal element is strontium, any one or both of these elements, and Cr, Mn and Group 8 of the fourth period of the element periodicity table Examples thereof include perovskite black powder composed of at least three elements including any element selected from the elements iron, cobalt and manganese.

  According to the study by the present inventors, it is particularly preferable to adjust the strontium content to be in the range of 90 to 100% of the content in the stoichiometric composition for the following reasons. That is, by configuring in this way, for example, characteristics such as oxygen storage and conductivity can be improved. The perovskite crystal structure contains different metals at the A site and the B site, the A site contains strontium, lanthanum, and the like, and the B site contains mainly transition metals and maintains a charge balance with oxygen. However, since strontium at the A site can take only two valences, oxygen vacancies are likely to occur depending on the strontium content, and this vacant site is considered to be a factor that improves characteristics such as oxygen storage properties and conductivity. Therefore, slightly reducing the strontium content leads to an improvement in characteristics, and specifically, an improvement in characteristics can be expected by adjusting the strontium content to a range of 90 to 100%. On the other hand, if the content of strontium is too small, it causes a decrease in crystallinity, and if it is too much, excessive strontium becomes an inhibiting factor and may deteriorate characteristics, which is not preferable. By performing wet preparation in consideration of the above-mentioned conditions, the functionality of the composite oxide material having the perovskite type and the similar crystal structure of the present invention can be improved, and further, while being a composite oxide , Excellent wettability to the resin.

  The method for producing the perovskite black powder of the present invention comprises at least 3 elements selected from rare earth elements and / or alkaline earth metal elements, Cr, Mn, and Group 8 elements of the Periodic Table of Elements as described above. A mixed salt aqueous solution of a salt of each constituent element and an alkaline aqueous solution that is an aqueous solution for precipitation, for example, an aqueous solution of soda ash, are dropped simultaneously into precipitation water, and the pH is more than pH 6 to less than pH 8. The precipitate is synthesized by filtration, washed with water, and dried to obtain a black powder precursor, and further, the precursor is fired to obtain a composite oxide having a primary particle size of 1 μm or more. It is characterized by that.

  As described above, in the present invention, in order to further enhance the functionality of the perovskite black powder, the object of the present invention is achieved by adopting a unique wet precipitation mixing method different from the conventional mixing performed conventionally. Has achieved. Specifically, by using a salt aqueous solution of three or more specific constituent elements and co-precipitating a precipitate containing these elements under a condition of more than pH 6 to less than pH 8, at least three elements It was possible to synthesize a microprecipitation mixture consisting of the above, and this was used as a precursor, thereby improving the reactivity during the subsequent firing of the precipitate and realizing a composite oxide excellent in functionality. As a result, the perovskite-based black powder of the present invention becomes a complex oxide having a primary particle size of 1 μm or more, which could not be obtained by conventional wet precipitation mixing, and the crystal structure is It is a soft powder compared to a perovskite type or similar, soft, dry-processed sintered body, and can realize high functionality. The perovskite black powder of the present invention obtained as described above is more preferably one having a primary particle size of 2 μm or more and 10 μm or less that can be applied to various uses.

  Hereinafter, the background to the present invention will be described. As a method for producing the inorganic material used in the field of obtaining composite oxides from a plurality of inorganic materials, substances containing constituent metal elements such as oxides, carbonates, hydroxides and the like in a predetermined stoichiometric amount. Generally, an inorganic material having a target crystal composition is obtained by uniformly mixing in a dry or wet process and baking. However, in this method, since the uniformity of the mixture is defined by the particle diameter of the raw material used, firing the mixture in that state affects the properties of the resulting composite oxide. That is, when a material having a large particle diameter is used, larger particles are mixed together, and when viewed microscopically, it cannot be said that they are uniformly mixed. Therefore, the uniformity is also ensured by dry pulverization or wet pulverization at the time of mixing, but it is difficult to say that it is sufficient.

  On the other hand, if the mixture to be fired is in a non-uniform state, more energy is required when the mixture is fired and crystallized, and it is necessary to raise the firing temperature. According to the study by the present inventors, the increase in the firing temperature and the irregularity of the particles due to sintering usually adversely affect the dispersion, kneading, molding, pelletizing, etc. of the particles provided as a post-process. In addition, when a large particle is refined, the crystal is broken by pulverization and causes a decrease in crystallinity, and this causes an adverse effect on material properties. In particular, in the production of a perovskite-based material that contains at least three elements selected from the rare earth elements and / or alkaline earth metal elements and Cr, Mn, and Group 8 elements used in the present invention, the constituent elements are calcined. Due to the fact that the unreacted alkaline earth metal is sometimes melted, it becomes easy to sinter, which causes a problem of deterioration in material properties. For these reasons, as a technical request, three or more kinds of different elements used in the present invention can be mixed more uniformly, and when the mixture is fired, it becomes a sintered body with high crystallinity and high hardness. There is a need to provide a perovskite-based black powder material that is difficult and easy to work in the above-described post-process.

  As a result of intensive studies on the above-described problems of the prior art, the present inventors are effective to perform wet precipitation mixing, and at that time, by performing wet precipitation mixing under specific conditions, It was found that composite oxides satisfying the requirements can be synthesized. That is, the perovskite black powder excellent in functionality and practicality intended by the present invention can be obtained for the first time by the following manner. First, under the condition of pH 6 to less than pH 8, each constituent element metal salt is microprecipitated using an alkaline precipitating agent to obtain a wet precipitation mixture, and this is used as a precursor of a black powder to be fired. As a result, the reactivity during firing can be increased. As a result, the precursor crystal grows during firing, has a perovskite type or similar flexible crystal structure, and has a primary particle size of 1 μm or more that could not be obtained by conventional methods. It becomes a complex oxide with crystal growth.

  When obtaining a composite oxide, the dry-mixed raw material powder is often fired to obtain a sintered body. In this case, since the raw material particles are large, the particle size of the mixture is good even if pulverized. However, the sub-micron range is the limit, and the mixing is not uniform as compared with the wet precipitation method. Therefore, in order to obtain the target perovskite crystal, a higher firing temperature is required. On the other hand, when the precursor of the black powder is obtained by the wet precipitation mixing method, the precipitate of each metal to be produced is very fine at the moment of precipitation as a so-called nanometer-sized fine particle. . For this reason, when viewed microscopically, much finer and more uniform mixing is achieved as compared with the conventional method of pulverizing and dry-mixing raw materials. Therefore, perovskite-type crystals manufactured using the wet precipitation mixing method can be fired at a lower temperature than when the dry mixing method is used, providing materials with high crystallinity and various characteristics. There is an advantage that you can. The perovskite black powder of the present invention can synthesize a better black powder precursor by using a unique wet precipitation mixing method, and is useful for various applications that further enhance these characteristics. Become.

  Examples of conventional techniques related to composite oxides using alkaline earth metals and rare earths include Patent Documents 1 to 3 described above. In Patent Documents 1 and 3, as a method other than the conventional dry production method, when producing a complex oxide black pigment whose constituent elements are rare earth, alkaline earth metal and iron, A method is described in which a mixed precipitate of hydroxides of the above-described elements is produced by a mixed aqueous solution of an compound and an alkaline aqueous solution, and the resulting precipitate is fired. However, in this method, unlike the present invention, when a mixed precipitate is obtained, a mixed aqueous solution of each elemental compound and an alkaline aqueous solution are precipitated with stirring at a precipitation pH of 8 to 14, preferably at a pH of 10 or more. It is added to the bath. The reason is that the precipitated particles become smaller in the high pH region, and the smaller the color, the better the coloring power. For this reason, the black pigment obtained in the examples of Patent Documents 1 and 3 is a fine pigment having a size of about 0.2 to 0.4 μm, and the primary particle diameter intended in the present invention has grown to 1 μm or more. The material is not available. Of course, there is no description about the usefulness of the material first achieved by the perovskite black powder of the present invention. In Patent Document 2, strontium iron oxide particle powder is obtained by wet pulverization, and the production method is completely different from the present invention.

  In contrast to the above-described prior art, in the present invention, the combination of constituent elements is three or more selected from a specific range, and when the wet precipitation is mixed, the pH value range is different from the range used in the prior art. By controlling to, a precursor is obtained that is microprecipitated and co-precipitated in a good state, and as a result, has a perovskite-type or similar flexible crystal structure and a primary particle size of Particles with crystal growth of 1 μm or more are obtained, making it possible to realize a composite oxide having excellent functionality.

  The method for producing the perovskite black powder of the present invention will be described more specifically. In the present invention, a composite oxide comprising at least three kinds of elements selected from rare earth elements and / or alkaline earth metal elements and elements selected from Cr, Mn and Group 8 elements of the periodic table is produced. In this case, a mixed salt aqueous solution of each constituent element salt and an alkaline aqueous solution that is an aqueous solution for precipitation are dropped simultaneously, and the pH is more preferably 6.5 or more and 7. A precipitate mixture is synthesized under conditions of 5 or less, and the precipitate mixture is filtered, washed with water, and dried to obtain a black powder precursor. Further, the precursor is fired to obtain a perovskite black powder which is a complex oxide having a primary particle size of 1 μm or more. Hereinafter, the manufacturing method of the present invention described above will be described in detail.

  Any commercially available metal salt of each constituent element used for obtaining the perovskite black powder of the present invention can be used, and nitrates, chlorides, sulfates, and the like can be used. However, when strontium is contained in the mixed salt aqueous solution, if sulfate is used, it precipitates as strontium sulfate, so that the use of sulfate is limited. The salt of each constituent metal constituting the mixed salt aqueous solution is precipitated by an alkaline aqueous solution (alkali precipitating agent) that is an aqueous solution for precipitation. The alkaline precipitating agent used at that time includes caustic soda, soda ash, sodium bicarbonate, ammonia. , Urea and the like, and any of them can be used.

  The metal salt of the constituent element used in the present invention is blended so as to have a predetermined blend according to the desired composite oxide, and is used by dissolving in dissolved water. The concentration of this mixed salt aqueous solution is 5-50. About mass% is appropriate. In any case, the alkali used as the precipitating material can be used in the range of about 5 to 30% by mass without any problem as long as the salt of each constituent metal can be precipitated.

  In the present invention, the metal salt aqueous solution of at least three kinds of constituent elements thus prepared and the alkaline aqueous solution that is the aqueous solution for precipitation are within a range of more than pH 6 to less than pH 8, and more preferably pH 6.5. Within the range of 7.5 or less, the hydroxides and carbonates of each element are deposited microscopically by simultaneously dropping into the precipitation tank while stirring. According to the study by the present inventors, for example, when precipitated in a high pH region of pH 8 or higher, the precipitated particles become smaller and the precipitation rate becomes faster. Primary particles tend to be large. Further, in this case, it was also found that the sizes of the precipitates of the respective constituent components are likely to be uneven, and the reactivity at the time of firing tends to decrease due to this. For example, when strontium is used as an alkaline earth metal, the particles are likely to be coarsened, and even if large particles are formed by firing the obtained precursor, the desired “perovskite type or similar” It has been found that crystals having a flexible crystal structure cannot be obtained. In the present invention, a precipitate mixture having excellent reactivity is synthesized while maintaining the pH below 8. On the other hand, in a very low pH region, it is difficult to precipitate the alkaline material, particularly when an alkaline earth metal such as strontium is used as a raw material.

  In the production method of the present invention, there is no problem if the precipitation temperature at the time of depositing the precipitation mixture is in the range of room temperature to 70 ° C. According to the study by the present inventors, when the precipitation temperature is lower than the above range, the precipitation of alkaline earth metal, which is a constituent element, for example, is slow, and the resulting black of three or more constituent elements is obtained. It causes blurring of the composition of the powder. On the other hand, when the temperature is higher than the above range, in addition to being not economical, precipitation of the rare earth metal is particularly fast and it is easy to produce a large particle size. More preferably, when a composite oxide precursor is synthesized by precipitation at a temperature of about 50 ° C. above 40 ° C., the material in a crystalline state with excellent functionality desired by the present invention is more easily stabilized after firing. Can be obtained.

  The precipitation mixture obtained as described above is aged by standing at a temperature of about 70 ° C. for about 30 minutes to 2 hours in order to ensure precipitation. The precipitated slurry thus obtained exists in a loosely agglomerated state and settles, and can be washed with water by decantation. In the present invention, in order to remove residual salt generated as a by-product, for example, it is washed with water until the electric conductivity becomes 300 μS / cm or less, and after completion of water washing, it is filtered with Nutsche (Buchner funnel) and dried at 120 ° C. for about 12 hours, for example. It is preferable to obtain a black powder precursor (crude).

  Since the precursor of the black powder obtained as described above is amorphous, in the present invention, it is crystallized by firing to provide functionality, and the desired “perovskite type or similar flexible crystal structure. A black powder with The firing conditions at this time are 900 ° C. to 1300 ° C. If the firing temperature is lower than this range, a perovskite crystal cannot be obtained. More preferable firing conditions are 1000 to 1200 ° C., and there is an advantage that firing can be performed at a low temperature as compared with the case of dry preparation. In addition, if the firing temperature is too higher than the above-mentioned range, sintering becomes intense, which is not preferable. When the sintering becomes intense, it becomes difficult to disperse, knead, mold and pelletize in the subsequent steps.

  The black powder obtained by the production method of the present invention as described above shows a perovskite type crystal structure having a very high crystallinity or a similar perovskite type crystal structure based on the powder X-ray diffraction measurement result. Compared with the sintered type crystal obtained by the dry process, it is soft and soft. In addition, unlike the case obtained by using the conventional wet precipitation mixing method, the primary particle size grows to 1 μm or more without becoming finer than 1 μm or agglomerating and coarsening. More preferably, the crystal grows to have a primary particle size of 2 μm or more and 10 μm or less.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, all are not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

<Example 1> (Wet precipitation mixed preparation: Sr-Co-Fe)
495.7 parts (Sr; 1.859 mol) of strontium chloride hexahydrate (266.6 g / mol) and 331.8 parts (Co; 1.395 mol) of cobalt chloride hexahydrate (237.9 g / mol) Then, 92.4 parts (0.465 mol) of ferrous chloride tetrahydrate (Fe; 198.8 g / mol) was dissolved in 1800 parts of dissolved water to prepare a mixed salt aqueous solution. Subsequently, 450 parts of soda ash (anhydrous sodium carbonate) was dissolved in 1400 parts of dissolved water as an alkaline aqueous solution to prepare a precipitation aqueous solution. Next, 3400 parts of water as the precipitating water was weighed in the beaker for precipitation for dropping the salt mixed aqueous solution and the alkaline aqueous solution prepared above, and the temperature of the precipitating water was raised to 50 ° C. and held. In this state, the salt mixed aqueous solution and the alkaline aqueous solution prepared above were dropped simultaneously while maintaining pH 6.6 to obtain a mixed slurry solution. After completion of the dropwise addition, the temperature of the mixed slurry solution was heated to 70 ° C. and left as it was for 1 hour to complete the reaction.

  Then, in order to remove the by-produced salt in the precipitation slurry, decantation was performed, and water washing was performed until the electric conductivity became 300 μS / cm or less. Next, the precipitated slurry was filtered with Nutsche, and the obtained cake was dried at 120 ° C. for 12 hours to obtain a target black powder precursor.

  Next, the black powder precursor obtained as described above was baked at 1050 ° C. in an electric furnace to obtain a target black powder. As shown in the SEM photograph of FIG. 1, the obtained black powder was crystal grown in a primary particle size range of 1 to 10 μm. Moreover, it was confirmed from the measurement of powder X-ray diffraction that the obtained black powder has a perovskite crystal structure with very high crystallinity. Moreover, when the oxygen adsorption amount of the black powder was measured from the difference in oxygen adsorption amount between nitrogen and air with a thermal analyzer, it was 5.0 ml / g. From the above, it was confirmed that the black powder obtained above exhibits high performance as an oxygen storage material. In this example, the ratio of Sr, Co and Fe calculated from the composition of the raw materials used is 75 mol for Co and 25 mol for Fe with respect to Sr = 100 mol.

<Example 2> (Wet precipitation mixed preparation: Sr-La-Co-Fe)
446.2 parts (Sr; 1.664 mol) of strontium chloride hexahydrate, 159.1 parts (La; 0.186 mol) of an aqueous lanthanum nitrate solution (pure 19% by mass as lanthanum oxide), cobalt chloride 6 398.2 parts (Co; 1.673 mol) of hydrate and 36.9 parts of ferrous chloride tetrahydrate (Fe; 0.186 mol) are dissolved in 1800 parts of dissolved water to prepare a salt mixed aqueous solution. did. Subsequently, 450 parts of soda ash was dissolved in 1400 parts of dissolved water as an alkaline aqueous solution to prepare an aqueous solution for precipitation. Next, 3400 parts of water was weighed out as precipitation water into the beaker for precipitation for dropping the salt mixed aqueous solution prepared above and the alkaline aqueous solution, and the temperature of the precipitation water was raised to 50 ° C. and held. . In this state, the salt mixed aqueous solution and the alkaline aqueous solution were dropped simultaneously while maintaining pH 6.6 to obtain a mixed slurry solution. After completion of the dropwise addition, the temperature of the mixed slurry solution was heated to 70 ° C. and left as it was for 1 hour to complete the reaction.

  The mixed slurry solution obtained as described above was washed with water, filtered and dried in the same manner as in Example 1 to obtain a black powder precursor. Next, this black powder precursor was fired at 1100 ° C. to obtain the intended black powder. It was confirmed that the obtained black powder was crystal-grown to the same particle size as the black powder of Example 1. The black powder had a perovskite crystal structure with very high crystallinity, as measured by powder X-ray diffraction. Further, the oxygen adsorption amount of the black powder was measured from the difference in oxygen adsorption amount between nitrogen and air with a thermal analyzer, and found to be 4.7 ml / g. From the above, it was confirmed that the black powder obtained above exhibits high performance as an oxygen storage material. In addition, the ratio of Sr, La, Co, and Fe calculated from the composition of the used raw material is 11.1 mol for La, 100 mol for Co, and 11.1 mol for Fe with respect to Sr = 100 mol.

  Further, in the above configuration, the content of the strontium content in the stoichiometric composition was changed to 90 to 102%, and the difference in oxygen adsorption amount due to the difference in strontium content was examined. As a result, as shown in Table 2, it was confirmed that when the strontium content was 90 to 100%, the oxygen storage material exhibited high performance.

<Example 3> (Wet precipitation mixed preparation: Sr-La-Co)
535.4 parts (Sr; 2.009 mol) of strontium chloride hexahydrate, 191.3 parts (La; 0.223 mol) of an aqueous lanthanum nitrate solution (pure 19% by mass as lanthanum oxide), cobalt chloride 6 353.9 parts of water salt (Co; 1.487 mol) was dissolved in 1100 parts of dissolved water to prepare a salt mixed aqueous solution. Next, as an alkaline aqueous solution, 500 parts of soda ash was dissolved in 1400 parts of dissolved water to prepare an aqueous solution for precipitation. Next, 3400 parts of water as the precipitating water was weighed into the beaker for precipitation in which the salt mixed aqueous solution prepared above and the alkaline aqueous solution were dropped, and the temperature of the precipitating water was raised to 50 ° C. and held. In this state, the salt mixed aqueous solution and the alkaline aqueous solution were simultaneously dropped while maintaining pH 6.7 to obtain a mixed slurry solution. After completion of the dropwise addition, the temperature of the mixed slurry solution was heated to 70 ° C. and left as it was for 1 hour to complete the reaction.

The mixed slurry solution obtained as described above was washed with water, filtered and dried in the same manner as in Example 1 to obtain a black powder precursor. Subsequently, the precursor of this black powder was baked at 1200 ° C. to obtain a target black powder. It was confirmed that the obtained black powder was crystal-grown to the same particle size as the black powder of Example 1. The black powder was confirmed to have a layered perovskite crystal structure from powder X-ray diffraction measurement. Further, the oxygen adsorption amount of the black powder was measured from the difference in oxygen adsorption amount between nitrogen and air with a thermal analyzer and found to be 2.3 ml / g. Moreover, when the electroconductivity of this black powder was measured at room temperature, it was 2.8 × 10 ³ S / cm. Since the conductivity of a normal perovskite oxide is about 10 ⁰ to 10 ⁻³ S / cm, it was found that the conductivity is considerably high. Thus, since it has higher conductivity than other materials, it can be used as a heat-resistant conductive material having oxygen adsorption properties. In addition, the ratio of Sr, La, and Co calculated from the composition of the used raw material is 11.1 mol of La and 74 mol of Co with respect to Sr = 100 mol.

<Example 4> (Wet precipitation mixed preparation: Sr-La-Mn)
449.1 parts of hexahydrate (Sr; 1.664 mol) of strontium chloride, 159.1 parts (La; 0.186 mol) of an aqueous lanthanum nitrate solution (pure 19% by mass as lanthanum oxide), manganese chloride 4 367.9 parts (1.860 mol) of a water salt (Mn; 197.8 g / mol) was dissolved in 1800 parts of dissolved water to prepare a mixed salt aqueous solution. Subsequently, 450 parts of soda ash was dissolved in 1400 parts of dissolved water as an alkaline aqueous solution to prepare an aqueous solution for precipitation. Next, 3400 parts of water as the precipitating water was weighed in the beaker for precipitation in which the mixed salt aqueous solution and the alkaline aqueous solution obtained above were dropped, and the temperature of the precipitating water was raised to 50 ° C. and held. In this state, a salt mixed aqueous solution and an alkaline aqueous solution were dropped simultaneously while maintaining pH 6.6 to obtain a mixed slurry solution. After completion of the dropwise addition, the temperature of the mixed slurry solution was heated to 70 ° C. and left as it was for 1 hour to complete the reaction.

  The mixed slurry solution obtained as described above was washed with water, filtered and dried in the same manner as in Example 1 to obtain a black powder precursor. Subsequently, this black powder precursor was baked at 1100 ° C. to obtain a target black powder. It was confirmed that the obtained black powder was crystal-grown to the same particle size as the black powder of Example 1. The black powder was confirmed to have a perovskite crystal structure with very high crystallinity by measurement of powder X-ray diffraction.

Moreover, it was 2.8 * 10 < ² > S / cm when the electroconductivity of the black powder obtained above was measured at room temperature. Since the conductivity of a normal perovskite oxide is about 10 ⁰ to 10 ⁻³ S / cm, it was found that the conductivity is considerably high. Thus, since it has higher conductivity than other materials, it can be used as a SOFC fuel cell air electrode material or a heat-resistant conductive material. Further, when the oxygen adsorption amount of the black powder was measured from the difference in oxygen adsorption amount between nitrogen and air with a thermal analyzer, it was 2.0 ml / g, which is lower than those obtained in Examples 1 and 2. However, there was oxygen adsorption. In addition, the ratio of Sr, La, and Mn calculated from the composition of the used raw materials is 11.1 mol for La and 111.1 mol for Mn with respect to Sr = 100 mol.

<Comparative Example 1> (dry mixing preparation: Sr-Co-Fe)
As raw materials, 147.6 parts (Sr; 1.0 mol) of solid strontium carbonate (147.6 g / mol) and 77.5 parts (Co; 0) of basic cobalt carbonate (516.7 g / mol), respectively. .75 mol) and 19.9 parts of ferric oxide (162.2 g / mol) (Fe; 0.25 mol) were weighed. Then, 5 mm alumina beads were used as media, and pulverized and mixed for 1 hour with a planetary ball mill (hereinafter abbreviated as planetary BM). Thereafter, a part of this was taken into a crucible made of mullite, raised to 1200 ° C. in a temperature rising time of 6 hours in an electric furnace, held at that temperature for 120 minutes, and fired after dry mixing. This product was allowed to cool naturally in an electric furnace as it was, and was removed when it reached room temperature. The obtained black powder was sintered, but in the case of a small amount, it could be pulverized, and pulverized in a mortar until no roughness was obtained, thereby obtaining a black powder having the same particle size as that obtained in the examples.

  The obtained black powder was confirmed to have a perovskite crystal structure from powder X-ray diffraction measurement. However, some unknown phases existed. Since it is considerably sintered, it was necessary to pulverize with a normal blade type pulverizer after crushing with a crusher or the like in the case of mass pulverization. The amount of oxygen adsorbed on the black powder was measured with a thermal analyzer from the difference in oxygen adsorbed in nitrogen and air, and found to be 3.4 ml / g. From the above, this can be used as an oxygen storage material, but the oxygen adsorption amount was about 70% as compared with the black powder of Example 1 made of similar constituent elements. In addition, the ratio of Sr, Co, and Fe calculated from the composition of the used raw material is 75 mol of Co and 25 mol of Fe with respect to Sr = 100 mol.

<Comparative Example 2> (Dry mixing preparation: Sr-La-Co-Fe)
As raw materials, solid, lanthanum oxide (325.8 g / mol) 16.3 parts (La; 0.1 mol), strontium carbonate 132.3 parts (Sr; 0.90 mol), basic cobalt carbonate 93.0 parts (Co; 0.9 mol) and 8.0 parts of ferric oxide (Fe; 0.1 mol) were weighed, and 5 mm alumina beads were used as media, and pulverized and mixed with planetary BM for 1 hour. Thereafter, a part of this was taken into a crucible made of mullite, raised to 1250 ° C. in a temperature rising time of 6 hours in an electric furnace, held at that temperature for 120 minutes, and dry-fired. This product was allowed to cool naturally in an electric furnace as it was, and was removed when it reached room temperature. The obtained black powder is sintered, but in the case of a small amount, it can be pulverized, and pulverized in a mortar until the roughness disappears, to obtain a black powder having a particle size of several μm, which is similar to that obtained in the example. .

  The obtained black powder was confirmed to have a perovskite crystal structure from powder X-ray diffraction measurement. However, some unknown phases existed. Since it was sintered considerably, it was necessary to pulverize with a normal blade type pulverizer after crushing with a crusher or the like when mass pulverizing. The amount of oxygen adsorbed on the black powder was measured with a thermal analyzer from the difference in oxygen adsorbed in nitrogen and air, and found to be 3.2 ml / g. From the above, this material can be used as an oxygen storage material, but the oxygen adsorption amount was about 70% compared to the black powder of Example 2 made of similar constituent elements. In addition, the ratio of Sr, La, Co, and Fe calculated from the composition of the used raw material is 11.1 mol for La, 100 mol for Co, and 11.1 mol for Fe with respect to Sr = 100 mol.

<Comparative Example 3> (Dry mixing preparation: Sr-La-Co)
As raw materials, 9.8 parts (La; 0.06 mol) of lanthanum oxide, 79.7 parts (Sr; 0.54 mol) of strontium carbonate, 41.3 parts of basic cobalt carbonate (Co; 0.4 mol), respectively. Were weighed, and 5 mm alumina beads were used as media, and pulverized and mixed with planetary BM for 1 hour. Thereafter, a part of this was taken into a crucible made of mullite, raised to 1250 ° C. in a temperature rising time of 6 hours in an electric furnace, held at that temperature for 120 minutes, and dry-fired. This product was allowed to cool naturally in an electric furnace and taken out when it reached room temperature. The obtained black powder is sintered, but in the case of a small amount, it can be pulverized, and pulverized in a mortar until the roughness disappears, to obtain a black powder having a particle size of several μm, which is similar to that obtained in the example. .

The obtained black powder was a mixed crystal of a layered perovskite structure and a normal perovskite structure from the powder X-ray diffraction measurement, and a partially different phase was observed. Since it was sintered considerably, it was necessary to pulverize with a normal blade type pulverizer after crushing with a crusher or the like when mass pulverizing. The amount of oxygen adsorbed on the black powder was measured by a thermal analyzer from the difference in the amount of oxygen adsorbed in nitrogen and air, and found to be 1.5 ml / g. Moreover, it was 1.8 * 10 < ² > S / cm when the electroconductivity of this black powder was measured at room temperature. Since the conductivity of a normal perovskite oxide is about 10 ⁰ to 10 ⁻³ S / cm, the conductivity is high, but it is considerably lower than that of Example 3 made of similar constituent elements. In addition, the ratio of Sr, La, and Co calculated from the composition of the used raw material is 11.1 for La and 75 mol for Co with respect to Sr = 100 mol.

<Comparative Example 4> (dry mixing preparation: Sr-La-Mn)
As raw materials, 4.9 parts (La; 0.03 mol) of lanthanum oxide, 39.8 parts (Sr; 0.27 mol) of strontium carbonate, and manganese dioxide (86.9 g / mol), respectively, 26. 07 parts (Mn; 0.30 mol) was weighed, and 5 mm alumina beads were used as media, and pulverized and mixed with planetary BM for 1 hour. Thereafter, a part of this was taken, put into a crucible made of mullite, raised to 1200 ° C. in a temperature rising time of 6 hours in an electric furnace, held at that temperature for 120 minutes, and dry-fired. This product was naturally cooled in an electric furnace as it was after firing, and taken out when it reached room temperature. The obtained black powder is sintered, but in the case of a small amount, it can be pulverized, and is pulverized in a mortar until the roughness is eliminated. Of black powder was obtained.

The obtained black powder was confirmed to have a perovskite crystal structure from powder X-ray diffraction measurement, but a partially unknown heterogeneous phase was present. Since it was sintered considerably, it was necessary to pulverize with a normal blade type pulverizer after crushing with a crusher or the like when mass pulverizing. The conductivity of this black powder was measured at room temperature and found to be 2.1 × 10 ¹ S / cm. Since the conductivity of a normal perovskite oxide is about 10 ⁰ to 10 ⁻³ S / cm, it is slightly higher than this, but compared with the black powder obtained in Example 4 using the same element as a raw material. Was quite low. In addition, the ratio of Sr, La, and Mn calculated from the composition of the used raw material is 11.1 mol for La and 111.1 mol for Mn with respect to Sr = 100 mol.

<Comparative Examples 5 and 6> (Wet precipitation mixed preparation: Sr—Co—Fe)
Using the same raw materials as prepared in Example 1, using a salt mixed aqueous solution and an alkaline aqueous solution obtained in the same manner, these were simultaneously dropped to obtain a mixed slurry solution. In that case, Comparative Example 5 Then, the pH was maintained at 8, and in Comparative Example 6, the solution was added dropwise while maintaining the pH at 10. Otherwise, a black powder was obtained in the same manner as in Example 1. At this time, the black powder precursor obtained after the precipitation had a very fast sedimentation in both Comparative Examples 5 and 6, and the whole was a feeling of a large aggregate. In Comparative Example 6, the sedimentation was particularly fast. The black powder obtained after firing is coarse and has an unknown heterogeneous phase from X-ray diffraction, which is not the “perovskite-type or similar flexible crystal structure” intended by the present invention. The reactivity was poor.

<Comparative example 7> (Wet precipitation mixing preparation: Sr-La-Co-Fe)
A salt mixture aqueous solution and an alkaline aqueous solution obtained in the same manner using the same raw materials as prepared in Example 2 were added dropwise at the same time to obtain a mixed slurry solution. At that time, the pH was adjusted to 10. Dropped while holding. Otherwise, a black powder was obtained in the same manner as in Example 2. At this time, the black powder precursor obtained after precipitation felt that the sedimentation was very fast and the whole was a large aggregate. The black powder obtained after firing is coarsened, an unknown heterogeneous phase is scattered from X-ray diffraction, and not the “perovskite type or similar crystal structure similar to this” intended by the present invention, The reactivity was also poor.

[Evaluation]
Regarding the composite oxides of the above-described Examples and Comparative Examples, the conditions of the production method and the characteristics of the obtained composite oxides were examined and evaluated by the following methods.

(1) Hardness Regarding the black powder of the example, the difference in hardness was confirmed as compared with the sintered body of the comparative example obtained by the dry manufacturing method comprising the same components, and at the same time, the black powder of the example was relatively Table 1 summarizes the results of the evaluation.

(2) Primary particle size The obtained black powder was observed with an electron microscope, the primary particle size was measured, and the range of the particle size was shown together in Table 1.

(3) Oxygen adsorption amount The oxygen adsorption amount of the black powder was measured from the difference in oxygen adsorption amount in air and nitrogen by a thermal analyzer. Specifically, air (21% oxygen, 79% nitrogen) and nitrogen (100%) are alternately flowed at a set temperature of 600 ° C. and normal pressure at a flow rate of 100 ml / min, and weight increase due to oxygen adsorption under air, The difference in weight loss due to the release of oxygen under nitrogen was observed, and the amount of adsorption was measured. Table 1 summarizes the results of the examples.

(4) Conductivity Weigh 5 g of the black powder to be measured in a 300 ml Erlenmeyer flask, add 100 ml of purified water or pure water (conductivity 2 μs / cm or less), heat, and hold for 5 minutes when the liquid boils. After cooling, the evaporated water is replenished to make the whole 100 ml, the pigment content is filtered, and the conductivity of the filtrate is measured with a conductivity meter (manufactured by Yokogawa Electric Corporation). The obtained results are shown in Table 1.

Claims (8)

As an element, including at least strontium as the alkaline earth metal elements, further rare-earth element, Cr, Mn, and any element selected from Co and elemental periodic table group 8 element including at least three Ri Do elemental, and, perovskite, wherein the content of said strontium 90 to 100% of the content in the stoichiometric composition, a composite oxide primary particle diameter of crystal growth than 1μm Black powder.   The perovskite black powder according to claim 1, wherein the primary particle size is 2 μm or more and 10 μm or less. The rare earth element is lanthanum, Group 8 elements of the previous SL Periodic table, perovskite type black powder according to claim 1 or 2 iron der Ru. The method for producing a perovskite black powder according to any one of claims 1 to 3 , wherein the aqueous salt solution is a mixed salt aqueous solution of three or more constituent elements containing at least strontium, and an aqueous solution for precipitation. Are simultaneously added dropwise to precipitation water to synthesize a precipitation mixture under conditions of pH 6 to less than pH 8, and the resulting precipitation mixture is filtered, washed with water, and dried to obtain a black powder precursor, A method for producing a perovskite black powder, characterized in that the precursor is fired to obtain a composite oxide having a primary particle size of 1 μm or more. The method for producing a perovskite black powder according to claim 4 , wherein the pH is 6.5 or more and 7.5 or less. The method for producing a perovskite black powder according to claim 4 or 5 , wherein a temperature at the time of synthesizing the precipitation mixture is in a range of room temperature to 70 ° C. The method for producing a perovskite black powder according to any one of claims 4 to 6 , wherein a firing temperature of the precursor is 900 ° C to 1300 ° C. A resin composition, wherein the perovskite black powder according to any one of claims 1 to 3 is dispersed and contained in a resin.