JP2006176636A - Organic and inorganic composite material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new organic and inorganic composite material in which aluminum oxide fine particles exist in an organic component while holding thickness in the minor axis direction of ≤5 nm without agglomerate each other with their platy surfaces, and a method for producing the organic and inorganic composite material easily by reacting in a short period of time at a room temperature under normal pressure by using inexpensive inorganic raw materials. <P>SOLUTION: This organic and inorganic composite material comprises at least one kind of organic polymer, selected from the group consisting of a polyurethane and a polyurea, and aluminum oxide fine particles with ≤5 nm minor axis diameter and ≥3 aspect ratio. It is obtained by bringing an organic solution, in which a kind of compound selected from the group consisting of a dichloroformate compound and a phosgene-based compound is dissolved in an organic solvent, into contact with an aqueous solution, in which an alkali aluminate and a diamine are dissolved in water, and reacting them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic-inorganic composite having polyurethane or polyurea and aluminum oxide fine particles having a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more, and a method for producing the same.

  For the purpose of imparting properties such as processability and flexibility of organic polymers and various properties of inorganic substances (dimensional stability, heat resistance, wear resistance, surface hardness, gas barrier properties), etc. A technique for compositing fine particles in an organic polymer has been widely studied. At this time, if the shape of the inorganic fine particles and the form of the dispersed state in the organic-inorganic composite can be controlled, it is possible to provide a composite in which the above functions are further enhanced. For example, when the inorganic fine particles are shaped to have a plate-like aspect ratio, the reinforcing effect in the longitudinal direction of the particles can be expressed more strongly than when the same amount of spherical fine particles is contained. In addition, when such plate-like fine particles are connected on the side surface of the plate and are present in the organic polymer in a structure that is randomly extended in any direction, the organic polymer can be reinforced with almost no anisotropy. .

Furthermore, the composite effect of the inorganic material can be further enhanced by making the particle size of the inorganic fine particles as small as possible and increasing the inorganic filling rate. This is because when the particle size of the inorganic particles is small, the surface area per weight of the inorganic particles is increased, and the interface region between the organic material and the inorganic material is widened to obtain a high reinforcing effect (area effect). This is because the higher the rate, the greater the effect of compounding (volume effect).

Conventionally, a melt-kneading method has been performed as one method for easily producing an organic-inorganic composite. In this method, finely divided inorganic substances are forcibly mixed in a molten organic component using a disperser or the like. In this method, inorganic particles are randomly dispersed in the organic component as can be inferred from the production method. It is only possible to control the distributed state. In addition, in this method, the aggregation of inorganic particles proceeds during the kneading process due to the affinity between the inorganic fine particles with high surface energy and the non-affinity between the organic material and the inorganic material. It is also very difficult to disperse. Further, fine particles having a thickness of 5 nm or less that do not aggregate in the minor axis direction (thickness direction) cannot exist by themselves.

  As another method, there are many methods of combining inorganic fine particles with an organic polymer using a so-called sol-gel method in which a metal alkoxide is hydrolyzed and polycondensed in the presence of an organic polymer to form a metal oxide. Are known. For example, Patent Document 1 describes an organic-inorganic composite using polyurethane as an organic polymer. However, this method has a problem that the production efficiency is extremely low because the hydrolysis of the metal alkoxide and the subsequent polycondensation (inorganic particle generation) reaction each take a long time. In addition, since it takes time to produce inorganic particles, the inorganic particles are deposited in a spherical shape so that the surface energy is minimized. Therefore, it is possible to synthesize an organic-inorganic composite having plate-shaped inorganic fine particles with a high reinforcing effect. Can not.

  On the other hand, as a method of combining a plate-shaped inorganic material with an organic material, a layered material such as clay mineral is used as an inorganic raw material, and the layer is sliced in an organic polymer to form a nano-order plate-shaped material. A method of conjugating in a polymer is known (for example, see Patent Documents 2 and 3). However, in this method, since a clay mineral having a low dispersibility with respect to an organic polymer and a strong bond between layers is used, a cation between the clay layers is previously ion-exchanged (organic modification treatment) with a quaternary ammonium salt having an alkyl group, etc. It is necessary to reduce the polarity of the layered material and the interlayer bonding force. Further, even if such treatment is performed, it is extremely difficult to completely remove all layers of the layered material. Therefore, the inorganic component of the organic-inorganic composite obtained by this method has a mixture with an aggregate with a thickness of several tens of nanometers with insufficient delamination, and the effect is higher than the amount of inorganic introduced. Not enough. In addition, it is substantially impossible to control the dispersion state of the inorganic fine particles by this method. In addition, when the amount of the inorganic component introduced is 10% by mass or more with respect to 100% by mass of the composite, poor dispersion or reaggregation of the inorganic component tends to occur. Furthermore, layered substances that are likely to be complexed with organic polymers are limited to materials having a low layer charge from the viewpoint of dispersibility with organic polymers, and are generally expensive because it is necessary to perform organic modification treatment as described above. There is also.

JP 2000-63661 A JP-A-11-256034 JP-A-11-131047

It is an object of the present invention to provide a novel organic / inorganic composite in which an aluminum oxide fine particle is present in an organic component while maintaining a thickness of a minor axis diameter of 5 nm or less without agglomerating between plate-like plate surfaces in an organic-inorganic composite. It is to provide a complex.
Another object of the present invention is to provide a production method capable of easily obtaining the organic-inorganic composite by a short-time reaction at normal pressure and room temperature while using an inexpensive inorganic raw material.

The present inventors contact an organic solution obtained by dissolving one compound selected from the group consisting of a dichloroformate compound and a phosgene compound in an organic solvent and an aqueous solution obtained by dissolving an alkali aluminate and a diamine in water. By performing a polycondensation reaction at 1. 1. Since aluminum has a trivalent valence, aluminum oxide is deposited in a plate shape with a thickness of 5 nm or less. It has been found that since a polymer is formed preferentially on the upper and lower surfaces of the deposited plate-like aluminum oxide, a novel organic-inorganic composite can be easily obtained in which the plate-like aluminum oxide does not aggregate between the plate surfaces. It was.

That is, the present invention is an organic-inorganic composite having at least one organic polymer selected from the group consisting of polyurethane and polyurea and aluminum oxide fine particles, wherein the fine particles have a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more. An organic-inorganic composite is provided.

In addition, the present invention is a method in which an organic solution in which one compound selected from the group consisting of a dichloroformate compound and a phosgene compound is dissolved in an organic solvent and an aqueous solution in which an alkali aluminate and a diamine are dissolved in water are contacted and reacted. A method for producing an organic-inorganic composite is provided.

The present invention can provide an organic-inorganic composite in which aluminum oxide fine particles having a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more are present in polyurethane and / or polyurea.

  In addition, according to the production method of the present invention, the organic-inorganic composite having the above characteristics can be easily obtained by a reaction of only one short stirring operation for 30 minutes or less at normal pressure and room temperature. Furthermore, in the present invention, an extremely inexpensive alkali aluminate can be used as a raw material for inorganic fine particles having a plate shape.

Hereinafter, the organic-inorganic composite of the present invention will be described in detail.
An organic-inorganic composite having an organic polymer selected from the group consisting of polyurethane and polyurea and aluminum oxide fine particles of the present invention, wherein the aluminum oxide fine particles have a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more. The organic-inorganic composite has a basic composition containing an organic solution (A) in which one compound selected from the group consisting of a dichloroformate compound and a phosgene compound is dissolved in an organic solvent, an alkali aluminate, and a diamine. It can obtain by mixing and stirring and making it react with aqueous solution (B).

In addition, according to this method, the inorganic component ratio can be increased to 10% by mass or more, and in this case, the aluminum oxide fine particles are connected in the major axis direction and have a structure that is randomly elongated in any direction. Thus, an organic-inorganic composite in which the characteristics of the inorganic material are strongly expressed can be provided.

(Components of aqueous solution (B))
The aqueous solution (B) used for the synthesis of the organic-inorganic composite of the present invention is composed of water, an alkali aluminate that is an inorganic raw material, and a diamine.

(Alkali aluminate)
The alkali aluminate used for the aqueous solution (B) in the present invention is XAlO ₂ (alkali metaaluminate), X ₃ AlO ₃ (alkali aluminate) or a co-solvent thereof, and X is an alkali metal. Is mentioned. Examples of these include sodium aluminate (soda), potassium aluminate, lithium aluminate and the like. In particular, sodium aluminate and potassium aluminate are particularly preferably used because of their high water solubility. Moreover, since these are used by dissolving in water, they can be suitably used regardless of whether they are liquids or hydrates. In addition, sodium aluminate is an extremely inexpensive material that is used in large quantities as a soil conditioner, a cement additive, and the like, and the use of such a material as a raw material for inorganic components is one of the features of the present invention. In the present invention, the reaction of the monomer (dichloroformate compound, phosgene compound) in the organic solution (A) with the diamine in the aqueous solution (B) synthesizes the polyamide by mixing the dicarboxylic acid halide and the diamine. Reactivity is slightly lower than reaction. Therefore, in order to promote the reaction, it is preferable to use an inorganic raw material that exhibits a high pH when dissolved in water. Since the alkali aluminate used in the present invention generally exhibits a high pH of 12 or more when water is used, any of them is preferably used.

(Action on synthesis of alkali aluminate complex)
An alkali metal contained in alkali aluminate is a remover of acid generated when polyurethane or polyurea is produced by polymerization of diamine with one compound selected from the group consisting of dichloroformate compounds and phosgene compounds. As a result, the polymerization reaction of polyurethane or polyurea is further accelerated. The aluminate from which the alkali metal has been removed passes through the aluminol group and bonds to each other while dehydrating and condensing to form nano-sized aluminum oxide fine particles. At this time, polymerization from the monomer to polyurethane or polyurea and chemical change from alkali aluminate to aluminum oxide proceed in parallel and in a complementary manner, so that one product is prevented from preferentially precipitating, A fine dispersion structure is formed. In particular, at that time, it is presumed that the aluminum ions are trivalent, so that the precipitation reaction proceeds preferentially in the two-dimensional direction, and a two-dimensional structure, that is, a plate-like aluminum oxide is generated.

According to this reaction mechanism, in order to produce plate-like aluminum oxide, an acid generated during polymer polymerization is essential, and conversely, it has an action as an acid removing agent in order to advance polymer polymerization. The alkali hydroxide generated when the alkali aluminate becomes aluminum oxide and precipitates is essential. Therefore, in this reaction, a nano-sized aluminum oxide plate is formed in a so-called bottom-up type, and the polymer is preferentially polymerized and generated around it, especially the upper and lower surfaces of the plate, which is the aluminum oxide production reaction part. Essentially, inorganic particles in which the surfaces of the plate-like material are aggregated are not generated. Therefore, inorganic fine particles are produced in the organic polymer as a fine particle plate structure having a very short axis diameter (thickness) of 5 nm or less.

In addition, in the present invention, since the content of the inorganic fine particles can be increased, the probability that the site where the plate-like inorganic fine particles are newly generated becomes the terminal portion of the already generated inorganic fine particles is increased. Therefore, a continuous body of inorganic fine particles in which the ends of plate-like nano fine particles are connected can be formed. The extension direction of the continuum at that time is not particularly determined because there are no other determinants, and tends to be in a winding state. As a result, when the composite is viewed macroscopically, an inorganic composite state having no anisotropy is obtained, and an organic-inorganic composite that strongly expresses the characteristics of the inorganic material can be provided.

(Controlling the content of inorganic compounds to be combined)
In the present invention, the ratio of the inorganic compound containing aluminum oxide to be complexed with the organic-inorganic composite can be easily controlled by the raw material used. By using an alkali aluminate having a large value of Al ₂ O ₃ / X ₂ O in the above chemical formula, that is, an alkali aluminate having a large amount of Al with respect to X, the ratio of aluminum oxide to be compounded can be increased. On the other hand, when it is desired to reduce the ratio of aluminum oxide to be compounded, in addition to using a small value of Al ₂ O ₃ / X ₂ O, the amount of alkali aluminate introduced into the aqueous solution (B) is small. At the same time, an acid acceptor such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate may be added to the aqueous solution (B) for the purpose of neutralizing the hydrogen halide generated during the polycondensation reaction.

In the present invention, the inorganic compound content is not particularly limited to 100% by mass of the composite. Even when the aluminum oxide content is as low as several percent or less, plate-like fine particles having a thickness of 5 nm or less and an aspect ratio of 3 or more exist without forming aggregates in the plate surface direction. The reinforcing effect of inorganic components is higher than that of organic-inorganic composites. In addition, in the present invention, an inorganic component of nanometer order of 10% by mass or more, which is difficult by a normal production method, can be easily combined without causing aggregation of the inorganic component. In this case, since the plate-like inorganic component is connected only at the terminal portion and is compounded in a tortuous state within the organic matrix, the organic-inorganic composite has a macroscopic anisotropy and strong inorganic properties. Is obtained. There is no particular restriction on the upper limit of the inorganic content, and that there is an upper limit to a number of Al 2 _{O 3} / _X 2 _O commercial alkali aluminate, the amount of the organic components is reduced, due to the organic material processing 60% by mass or less is preferable because characteristics such as property and flexibility are lost.

(Diamine)
The diamine in the aqueous solution (B) can be used without particular limitation as long as it reacts with each monomer in the organic solution (A) to produce an organic polymer. Specifically, aliphatic diamines such as 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane; m-xylylenediamine , P-xylylenediamine, m-phenylenediamine, p-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, and other aromatic diamines; Examples include aromatic diamines substituted with atoms, nitro groups, alkyl groups, and the like. These may be used alone or in combination of two or more.

(Introduction of inorganic components other than aluminum oxide)
In the present invention, other alkali metal complex oxides (for example, alkali zincate, alkali stannate, alkali manganate, alkali molybdate, alkali tungstate, alkali niobate, antimonic acid, which can coexist in the aqueous solution (B) in the dissolved state. (Alkali, etc.) is further dissolved in the aqueous solution (B), and other metal oxides are introduced into the inorganic fine particle component within the range having the same shape as the complex of aluminum oxide alone. You may do it. This method can also provide an organic-inorganic composite in which the particle shape and composite state of the inorganic component are not significantly different from those of a composite of aluminum oxide alone.

(Components of organic solution (A))
The organic solution (A) used for the synthesis of the organic-inorganic complex in the present invention is composed of one compound selected from the group consisting of a dichloroformate compound and a phosgene compound and an organic solvent for dissolving the compound.

(Dichloroformate compound)
Examples of the dichloroformate compound in the organic solution (A) include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,8-octanediol. All the hydroxyl groups of aliphatic diols such as chlorogenated by phosgenation treatment; resorcin (1,3-dihydroxybenzene), hydroquinone (1,4-dihydroxybenzene), 1,6-dihydroxynaphthalene, 2, 2'-biphenol, bisphenol S, bisphenol A, tetramethylbiphenol, etc., all of the hydroxyl groups of dihydric phenols having two hydroxyl groups on one or more aromatic rings are chlorogenated by phosgenation treatment Can be mentioned. These can be used alone or in combination of two or more.

(Phosgene compounds)
Examples of the phosgene compound in the organic solution (A) include phosgene, diphosgene and triphosgene. These may be used alone or in combination of both species.
In the present invention, by selecting a monomer in the organic solution (A), the type of the organic polymer that is the matrix of the complex can be changed. When a dichloroformate compound is used as a monomer, polyurethane can be obtained, and when a phosgene compound is used, polyurea can be obtained by reaction with a diamine in the aqueous solution (B).

(Organic solvent used for organic solution (A))
As an organic solvent used in the organic solution (A) in the present invention, any solvent that does not react with the various monomers and diamines in the organic solution (A) and dissolves the various monomers in the organic solution (A) can be used. It can be used without particular limitation. Among these, organic solvents incompatible with water include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane, halogenated hydrocarbons such as chloroform and methylene chloride, and fats such as cyclohexane. Cyclic hydrocarbons can be mentioned. Representative examples of the organic solvent compatible with water include ethers such as tetrahydrofuran, ketones such as methyl ketone and methyl ethyl ketone, and alkyl acetates such as ethyl acetate and propyl acetate.

  The monomer concentration in the organic solution (A) and the diamine concentration in the aqueous solution (B) are not particularly limited as long as the polycondensation reaction proceeds sufficiently, but from the viewpoint of bringing each monomer into good contact, 0.01 A concentration range of ˜3 mol / L, particularly 0.05 to 1 mol / L is preferred.

(Organic / inorganic composite production equipment)
The production apparatus used for production of the composite is not particularly limited as long as it is an apparatus that can satisfactorily contact the organic solution (A) and the aqueous solution (B). Is possible. However, since the polycondensation reaction takes several minutes to 30 minutes, it is preferable to use a batch type stirring device in order to ensure a sufficient reaction time. As a batch-type device, it is necessary to make good contact between the organic solution (A) and the aqueous solution (B). Therefore, a general-purpose stirring device having a propeller blade, a Max blend blade, a Faudler blade, etc. Can be used.

  The polycondensation reaction between the monomer in the organic solution (A) and the diamine in the aqueous solution (B) proceeds sufficiently in a temperature range of, for example, −10 to 50 ° C. near room temperature. Therefore, the temperature at which the organic solution (A) and the aqueous solution (B) are brought into contact with each other is set to a temperature range of about −10 to 50 ° C. near room temperature. At this time, neither pressurization nor decompression is required. The polycondensation reaction is usually completed in 30 minutes or less, depending on the type of monomer used and the reaction apparatus.

(Use of organic-inorganic composite)
In the organic-inorganic composite obtained by the present invention, the inorganic fine particles as the reinforcing component are plate-like having an aspect ratio, and the particle size can be extremely small and the content can be increased. It can be used as a reinforcing agent for polymers. In this case, the dimensional stability against temperature change and the effect of reinforcing various mechanical strengths can be enhanced as compared with the case of using an organic-inorganic composite having spherical fine particles. Further, since the composite has processability due to organic components, it can be pressure-molded and can be used as various structural materials. Further, the composite can also be used as a polar solvent absorber that holds a large amount of polar solvent (10 times or more with respect to the weight of the composite) due to the high inorganic fraction and the polar group of the organic component. In particular, when the polar solvent is an electrolyte, it can also be used as an electrochemical device such as a battery separator holding the electrolyte, a capacitor separator, or an electrochromic display element separator.

  In particular, when the organic polymer component is polyurea, it can be synthesized using phosgene, which is used in a very wide range as various raw materials. . In addition, among the above uses, particularly when used as a polar solvent absorber or an electrolyte solution holder, a large amount of the urea bond, which is a polar group, is present with respect to the total complex weight. It can be made particularly high and can be used suitably.

  Hereinafter, the present invention will be described more specifically with reference to examples. Unless otherwise specified, “part” means “part by mass”.

(Example 1: Synthesis 1 of aluminum oxide / polyurea complex)
1,4-diaminobutane 1.21 parts in ion-exchanged water 38.5 parts, sodium aluminate powder P-100 manufactured by Asada Chemical Co., Ltd. (Al ₂ O ₃ , 54 mass%, Na ₂ O, 36 mass%) 2.43 parts were added, and the mixture was stirred at 25 ° C. for 15 minutes to obtain a homogeneous transparent aqueous solution (B). An organic solution (A) in which 1.34 parts of triphosgene was dissolved in 44.4 parts of toluene while the aqueous solution (B) was charged into a 300 ml Separa flask at room temperature and stirred at 300 revolutions per minute using an anchor blade. Was added dropwise over 20 seconds. From 5 minutes after the start of stirring, a white cotton-like product gradually started to precipitate. Since no increase was observed in the production amount after 15 minutes, the synthesis operation was completed 25 minutes after the start of stirring. The liquid in which the white product obtained by this operation was dispersed was filtered under reduced pressure on a filter paper having an opening of 4 μm using a Nutsche having a diameter of 90 mm. The product on Nutsche was dispersed in 100 parts of methanol, stirred for 30 minutes with a stirrer, and filtered under reduced pressure for washing treatment. Subsequently, a similar washing operation was performed using 100 parts of distilled water, followed by filtration under reduced pressure to obtain a wet cake of a white aluminum oxide / polyurea complex.

(Example 2: Synthesis 2 of aluminum oxide and polyamide composite)
The sodium aluminate used in the aqueous solution (B) of Example 1 was added to 4.60 parts of sodium aluminate solution # 2019 (Al ₂ O ₃ , 20% by mass, Na ₂ O, 19% by mass) manufactured by Asada Chemical Co., Ltd. In the same manner as described in Example 1, except that the diamine used was changed to 1.53 parts of 1,6-diaminohexane and the amount of ion-exchanged water used was changed to 45.5 parts. A composite wet cake was obtained.

(Example 3: Synthesis of aluminum oxide / polyurethane composite)
(Synthesis of dichloroformate compound)
Triphosgene 2.835 parts was added to 2.583 parts of 1.4-butanediol and stirred for 30 minutes at room temperature to completely dissolve the triphosgene. Further, 3.000 g of triphosgene was added and stirred at room temperature for 30 minutes to obtain a viscous light yellow transparent liquid. The liquid was subjected to vacuum treatment at 0.02 MPa for 3 hours while stirring to remove the remaining excess triphosgene and hydrogen chloride generated when the diol was chloroformated with the phosgene compound. By the above operation, butane-bis-chloroformate ester in which both ends of 1.4-butanediol were chloroformated was obtained.

(Synthesis of aluminum oxide / polyurethane composite)
As the organic solution (A), white oxidation was performed in the same manner as described in Example 1, except that 2.924 parts of butane-bis-chloroformate was dissolved in 44.4 parts of toluene. A wet cake of an aluminum / polyurethane composite was obtained.

(Comparative Example 1)
(Comparative Example 1: Aluminum oxide / polyurea composite prepared by melt kneading method)
(Synthesis of polyurea containing no aluminum oxide)
A polyurea wet cake containing no inorganic components is obtained by synthesis in the same manner as in Example 1 except that 1.247 parts of sodium hydroxide is used instead of sodium aluminate in the aqueous solution (B). It was. The obtained polyurea wet cake was dried at 120 ° C. for 2 hours to obtain a dried polyurea. 10 parts of polyurea thus obtained and 5.0 parts of aluminum oxide powder having an average particle diameter of 100 nm were melt-kneaded at 200 ° C. in a small twin screw extruder MP2015 made by Tsubako, thereby forming a pellet-like organic material. An inorganic composite was obtained. The raw material charging operation prior to the kneading operation is very difficult because powder scattering due to the extremely small particle size of aluminum oxide is likely to occur.

<Evaluation of material properties of various composites>
The composite obtained by the above operation was measured for the following items, and the results obtained are shown in Table 1.

(1) Measuring method of inorganic compound content (ash content):
The measuring method of the content rate of the inorganic compound contained in each material is as follows.
Each material was completely dried in air at 120 ° C. for 2 hours to obtain a dry composite. This was precisely weighed (composite mass) and then calcined in air at 600 ° C. for 3 hours to completely burn off the organic polymer component, and the mass after firing was measured to obtain the ash mass (= aluminum oxide mass). The aluminum oxide content was calculated from the following formula.
Aluminum oxide content (mass%) = (mass ash / composite mass) × 100
In the composites obtained in Examples 1 to 3, even when the organic polymer was removed by firing, the shape before firing was maintained, whereas in the composite obtained in Comparative Example 1, the prototype was not retained. .

(2) Measurement of particle size of inorganic compound in composite and observation of dispersion state:
The composite was hot-pressed for 2 hours under conditions of 170 ° C. and 20 MPa / cm ² to obtain a flake made of the composite having a thickness of about 1 mm. This was made into an ultrathin section having a thickness of 75 nm using a microtome. The obtained section was observed with a transmission electron microscope “JEM-200CX” manufactured by JEOL Ltd. In Examples 1 and 3, aluminum oxide has a short axis diameter of 5 nm or less and a linear shape having an aspect ratio of a certain level or more (since the cross section is linear, the inorganic fine particles are considered to be plate-like. As a dark image) The majority of the aluminum oxide particles had a connecting structure with other particles on the side of the plate, while the surfaces of the plate were agglomerated. In Example 2, aluminum oxide particles having a minor axis diameter of 5 nm or less were dispersed independently because the content of the inorganic component was lower than in Examples 1 and 3. However, some of the particles had a connecting structure with other fine particles on the side of the plate as in Examples 1 and 3. On the other hand, in Comparative Example 1, Most grains of aluminum oxide Were observed to form aggregates and exist in the polymer as coarse particles of 1 μm or more, and is a transmission electron micrograph of the aluminum oxide / polyurea composite synthesized in Example 1. FIG. .

Subsequently, the following items were measured from the TEM photograph.
1. Average minor axis diameter: The length of the minor axis of each inorganic compound particle was measured, and the average value of 100 particles was defined as the measured value.
2. Particle average aspect ratio: The lengths of the major axis and minor axis of the inorganic compound particles were measured, the numerical values of the major axis / minor axis were calculated for each particle, and the average value of 100 particles was taken as the actual measurement value.
In addition to these, Table 1 also shows the maximum minor axis diameter (thickness) of the measured particles, the minimum particle aspect ratio, and the presence or absence of a connecting structure on the side surface of the inorganic fine particles.

The various physical properties of each Example and Comparative Example organic-inorganic composite obtained by the above measurement and the measurement results from the TEM photograph are summarized in Table 1.

As shown in Table 1, in Comparative Example 1, although aluminum oxide powder having an average particle size of 100 nm was used, aggregation of the aluminum oxide component occurred in the kneading process, and nanometer order composites could be performed. There wasn't. Moreover, the shape is also an indeterminate particle lump, and could not be controlled to a plate shape or the like. On the other hand, the aluminum oxide fine particles according to the present invention are organic particles having plate-like nanometer order fine particles having a shape with a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more (that is, no aggregates). An inorganic composite could be obtained. In addition, Examples 1 and 3 had a structure in which the plate-like aluminum oxide fine particles were contained at a high content of 40% by mass or more and were connected to the plate side surface (in the long axis direction). Even in Example 2 where the content was low, a similar structure was partially included.
Further, in the present invention, an organic-inorganic composite having the above characteristics can be obtained by using an inexpensive sodium aluminate as a raw material for an inorganic component by a short operation of 30 minutes or less under normal temperature and pressure.

2 is a transmission electron micrograph of the aluminum oxide / polyurea composite synthesized in Example 1. FIG.

Claims (4)

An organic-inorganic composite having at least one organic polymer selected from the group consisting of polyurethane and polyurea and aluminum oxide fine particles, wherein the aluminum oxide fine particles have a minor axis diameter of 5 nm or less and an aspect ratio of 3 or more. Inorganic composite. The organic-inorganic composite according to claim 1, wherein the aluminum oxide fine particles have a structure in which the fine particles are connected in the major axis direction. The organic-inorganic composite according to claim 1 or 2, wherein the content of aluminum oxide fine particles in 100% by mass of the composite is 10 to 60% by mass. An organic solution (A) in which one compound selected from the group consisting of a dichloroformate compound and a phosgene compound is dissolved in an organic solvent and an aqueous solution (B) in which an alkali aluminate and a diamine are dissolved in water are contacted and reacted. The manufacturing method of the organic inorganic composite as described in any one of Claims 1-3 characterized by the above-mentioned.

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