JP3853025B2 - Aluminum nitride powder and method for producing the same - Google Patents

Description

【００５４】
【発明の効果】
本発明によって得られる窒化アルミニウム粉末は、非常に高い耐水性を有し、更に、イオン性成分の溶出も抑制できる。また、優れた流動性を付与でき、凝集体を形成することがないので、樹脂への混練の際樹脂中に均一に分散することができる。
また、放熱が要求される電子部品の封止材、電子部品の接着材料や積層基板の成形材料等の樹脂材料用のフィラーとして有用である。また、耐水性が非常に高く、イオン性成分の溶出が少ないので、高温耐湿下でも使用でき、従来技術より信頼性の高い製品を得ることができる。
さらに、高温用炉材等の構造用材料として使用する際、成形時にバインダーとして水系のものを使用しても、加水分解しないので、窒化アルミニウム粉末の本来の特性を失うことがない。すなわち、本発明の窒化アルミニウム粉末を用いれば、引火性、且つ有害な有機溶媒をバインダーとして用いる必要がなく、安価な水が使用できるので、環境面の改善と安価なコストで高温炉材等を製造できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum nitride powder that is excellent in fluidity and water resistance and has low elution of ionic components, and a method for producing the same.
[0002]
[Prior art]
Aluminum nitride powder is known as a material having excellent thermal conductivity, mechanical strength, and electrical insulation, and is being used in various fields such as structural materials and functional materials. However, at the same time, aluminum nitride powder has the property of being easily hydrolyzed, and even water in the atmosphere is easily decomposed to produce aluminum hydroxide and ammonia according to the following formula (1). There is a problem that characteristics are lost.
[0003]
AlN + 3H ₂ O → Al (OH) ₃ + NH ₃ (1)
Therefore, when used as a structural material such as high-temperature furnace materials, if the binder used at the time of molding is aqueous, it will hydrolyze and lose the original characteristics of the aluminum nitride powder. Must be used. Further, functional materials such as white plates and metallized substrates also have a problem of performance deterioration due to hydrolysis. Further, semiconductor elements such as semiconductor devices and ICs are protected from the outside by a package. The package uses a polymer material, and the polymer material itself has low thermal conductivity, so heat generated from circuits using semiconductor elements is dissipated and removed to the outside, so it has excellent thermal conductivity. Inorganic fine particles (silica, boron nitride, aluminum nitride, etc.) are used as fillers for resins. In recent years, aluminum nitride having higher thermal conductivity has been used as a filler. Even when used as a filler for resin, moisture in the air permeates the film, and the aluminum nitride powder is hydrolyzed, resulting in a decrease in thermal conductivity and deterioration of the resin. Thus, when using aluminum nitride powder for the above-mentioned use, it is necessary to impart a property of suppressing the progress of hydrolysis (hereinafter referred to as water resistance).
[0004]
Thus, studies have been made to impart water resistance to aluminum nitride powder. For example, a method of using a polymerizable monomer as a surface coating agent for aluminum nitride powder (JP-A-1-179711), an organic silicon coupling agent having a siloxane bond (JP-A-7-33415) ), Hydroxyl group, amine group, carboxyl group (JP-A-3-261665, JP-A-6-345538), or α-alumina produced by firing aluminum nitride powder in an atmosphere containing some oxygen. What is formed (Japanese Patent Laid-Open No. 4-175209) is disclosed. However, these methods cannot provide sufficient water resistance.
[0005]
The present inventors have been able to obtain an aluminum nitride powder having excellent water resistance by treating the aluminum nitride powder with a phosphoric acid compound in the presence of water and containing a specific amount of the phosphoric acid compound on the surface of the aluminum nitride. (Japanese Patent Application No. 8-11371, Japanese Patent Application No. 8-286780). However, there is a demand for aluminum nitride powder having higher water resistance in various fields, and at the same time, there is a demand for reduction of ionic components that are eluted.
[0006]
Moreover, although excellent water resistance can be obtained by the method described in Japanese Patent Application No. 8-286780, the surface state is changed by the treatment with the phosphoric acid compound, and the fluidity is remarkably lowered as compared with the untreated one. For this reason, since the water-resistant aluminum nitride has poor fluidity, it is difficult for the aluminum nitride powder to form aggregates and uniformly disperse in the resin when kneaded with the resin. For example, when kneading aluminum nitride powder with a resin, it is necessary to knead while classifying with a sieve, which increases the number of processes and leads to an increase in cost.
[0007]
[Problems to be solved by the invention]
The object of the present invention is to (1) provide superior water resistance, (2) suppress elution of ionic components, and (3) provide excellent fluidity.
[0008]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that aluminum nitride having a specific amount of phosphoric acid compound on the surface of the aluminum nitride powder has excellent water resistance, and as a result of further investigation, the specific amount of phosphoric acid compound Is added to the surface of the aluminum nitride powder and a specific fluidity improver is added, so that (1) more excellent water resistance is provided, (2) the elution of ionic components is suppressed, and (3) excellent fluidity. The inventors have found that the purpose of providing can be achieved, and have completed the present invention.
[0009]
That is, the present invention is an aluminum nitride powder containing a fluidity improver and treated with a phosphoric acid compound, wherein the phosphoric acid compound is added to the aluminum nitride powder. ₂ O ₅ Treated with a phosphoric acid compound in the presence of water and aluminum nitride powder having excellent fluidity and water resistance, characterized by containing 0.1 to 10% by weight in terms of conversion and low elution of ionic components In addition, the present invention relates to a method for producing an aluminum nitride powder characterized by mixing a fluidity improver.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The aluminum nitride powder used in the present invention is not different depending on the production method, and a commonly used aluminum nitride powder can be used. For example, aluminum nitride produced by reacting an organoaluminum compound with ammonia and then heating it, an alumina reduction method in which a mixture of alumina and carbon is heated in nitrogen, a direct nitridation method in which aluminum and nitrogen are reacted, etc. Any powder can be suitably used. Among them, it is preferable to use an aluminum nitride powder obtained by a gas phase reaction method which is well-familiar with the resin and can be filled in the resin in a large amount.
[0011]
The aluminum nitride powder treated with a phosphoric acid compound referred to in the present invention is an aluminum nitride powder containing a phosphoric acid compound on the surface of the aluminum nitride powder, and at least a part of the aluminum on the surface of the aluminum nitride powder is bonded with an aluminum phosphate bond (Al- This refers to the aluminum nitride powder forming OP), and the bonding state around it is not specified. Probably, the present inventors consider that this aluminum phosphate layer is a water-resistant layer, and it has been experimentally confirmed that performance such as high-temperature water resistance and long-term water resistance can be imparted by some Al—O—P bonds. Have confirmed.
[0012]
In the present invention, the phosphoric acid compound (aluminum phosphate) P present on the surface of the aluminum nitride powder is used. ₂ O ₅ By specifying the content in terms of conversion, excellent water resistance can be imparted to the aluminum nitride.
[0013]
This water-resistant aluminum nitride powder contains phosphoric acid compound P ₂ O ₅ It is necessary to contain in the range of 0.1 to 10% by weight in terms of conversion, preferably 0.3 to 8% by weight, and more preferably 0.5 to 6% by weight. P of water resistant aluminum nitride powder ₂ O ₅ If the content is less than 0.1% by weight, the desired water resistance cannot be obtained, and if it exceeds 10% by weight, the desired water resistance and fluidity can be obtained, but the oxygen content of aluminum nitride is not sufficient. It becomes high and the thermal conductivity which is the original characteristic of the aluminum nitride powder is impaired. Further, since the amount of unreacted phosphoric acid compound increases, the eluting phosphoric acid compound increases, leading to an increase in the eluting ionic component, which is not preferable.
[0014]
The treatment of the aluminum nitride powder of the present invention with a phosphoric acid compound refers to an operation in which the phosphoric acid compound and the aluminum nitride powder are brought into contact. For example, the aluminum nitride powder is dispersed in the phosphoric acid compound solution or the aluminum nitride powder is kneaded into the phosphoric acid compound solution. For example, it may be made into a paste. Any method may be used as long as the phosphoric acid compound and aluminum nitride are in contact with each other.
[0015]
The phosphoric acid compound referred to in the present invention reacts with aluminum on the surface of the aluminum nitride powder to form an aluminum phosphate bond (Al—O—P bond), and finally has the ability to coat the aluminum nitride powder with an aluminum phosphate layer. Inorganic phosphoric acid compounds such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphonic acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, lauryl acid Acid phosphates such as phosphate, palmityl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, phenyl acid phosphate, nonyl phenyl acid phosphate, di-2-ethylhexyl pyrophosphate Mono- or dialkyl pyrophosphoric acid or polyphosphoric acid over preparative like, alkenyl or aryl esters, methylene phosphonic acid, organic phosphoric compounds such as phosphonic acids and esters thereof such as aminomethylene phosphonic acid and the like as an example. Also, a mixture of two or more types of phosphoric acid compounds may be used.
[0016]
In the present invention, a phosphoric acid compound is used as a solution. At that time, the above phosphoric acid compound dissolved in water or water and an organic solvent is used. The water used may be pure water or city water. The organic solvent is not particularly limited as long as it dissolves the phosphoric acid compound, but is preferably water-soluble because it requires the presence of water. For example, methanol, ethanol, isopropanol, butanol, tetrahydroxyfuran (THF) and the like can be mentioned. In the case of a phosphoric acid compound that is insoluble in such a water-soluble organic solvent, a water-insoluble organic solvent such as hexane, heptane, benzene, and toluene may be used in combination with the water-soluble organic solvent.
The concentration of the phosphoric acid compound used here is not particularly limited, but a concentration of 0.01% by weight or less is not preferable because desired water resistance cannot be obtained.
[0017]
The amount of the phosphoric acid compound used with respect to the aluminum nitride powder is preferably in the range of 0.03 to 200 parts by weight, more preferably 0.3 to 100 parts by weight, most preferably 0.3 to 100 parts by weight with respect to 100 parts by weight of the aluminum nitride powder. 60 parts by weight is preferred. If the amount is less than 0.03 part by weight based on 100 parts by weight of the aluminum nitride powder, the desired water resistance cannot be obtained, and if it exceeds 200 parts by weight, the desired water resistance and fluidity can be obtained. This is not preferable because the oxygen content of aluminum becomes high and the thermal conductivity, which is the original characteristic of aluminum nitride, is impaired. Further, since the amount of unreacted phosphoric acid compound increases, the eluting phosphoric acid compound increases, leading to an increase in the eluting ionic component, which is not preferable.
[0018]
The presence of water when the aluminum nitride powder is treated with the phosphoric acid compound is an important point in the present invention. This is because the presence of water forcibly hydrolyzes the surface of the aluminum nitride powder to generate aluminum hydroxide, which is an active site that reacts with the phosphoric acid compound. This increase in the active points promotes the formation of aluminum phosphate bonds (aluminum phosphate layer), so that high water resistance can be obtained. The inventors have experimentally confirmed this. The amount of water used is 1 part by weight or more with respect to 100 parts by weight of the aluminum nitride powder. If the amount is less than 1 part by weight relative to 100 parts by weight of the aluminum nitride powder, the active sites do not increase, so formation of a water-resistant layer is not promoted, and high water resistance cannot be obtained. In addition, since the formation of the water-resistant layer is very fast, hydrolysis with water proceeds and the original characteristics of the aluminum nitride powder are not impaired.
[0019]
The temperature at which the aluminum nitride powder is treated with the phosphoric acid compound cannot be generally determined depending on the conditions such as the amount of the phosphoric acid compound and water used, but is preferably in the range of 0 to 100 ° C, more preferably 18 to 50 ° C. . If the treatment temperature is less than 0 ° C., the surface of the aluminum nitride is not easily hydrolyzed, so that the active sites that react with the phosphoric acid compound do not increase, and the reaction with the phosphoric acid compound does not proceed, so the desired water resistance cannot be obtained. In addition, when the treatment temperature exceeds 100 ° C., water resistance can be obtained, but the reaction between the aluminum nitride powder and the phosphoric acid compound proceeds excessively and the original characteristics of the aluminum nitride powder are impaired.
[0020]
The time for treating the aluminum nitride powder and the phosphoric acid compound is not generally determined depending on the concentration, amount of use, temperature, etc. of the phosphoric acid compound, but is preferably 1 to 120 minutes, and more preferably 5 to 60 minutes.
[0021]
In addition to the above-mentioned treatment of the phosphoric acid compound, by further mixing a fluidity improver, (1) imparting better water resistance to the aluminum nitride powder (2) suppression of elution of ionic components (3) The purpose of imparting excellent fluidity can be achieved. It is speculated that the reason for the remarkable performance improvement is that the fluidity improver particles exist on the surface of the aluminum nitride powder having the aluminum phosphate layer. Presumably, the presence of flow improver particles on the surface of the aluminum nitride powder having a phosphoric acid compound suppresses the elution of the unreacted phosphoric acid compound, thereby suppressing a decrease in water resistance due to the elution of the phosphoric acid compound, As a result, it may be considered that the water resistance is improved and the elution of the ionic component is suppressed.
[0022]
Examples of the fluidity modifier in the present invention include silica, alumina, titania, boron nitride, and inorganic powder having a lipophilic group on the surface. Also, a mixture of two or more fluidity modifiers may be used. The particle size of these fluidity modifiers is preferably 1 μm or less.
[0023]
The inorganic powder having a lipophilic group on the surface of the present invention is an inorganic powder in which the surface of the inorganic powder is coated with resin, silicon oil, silicone, fluorine compound, etc., and the surface of the inorganic powder is covered with a lipophilic group. Means that. Examples thereof include silica having a lipophilic group on the surface (hereinafter referred to as water-repellent silica).
[0024]
In particular, when an inorganic powder having a lipophilic group on the surface is used as a fluidity modifier, the water resistance and fluidity of aluminum nitride are remarkably improved, and the effect of suppressing elution of ionic components is great. In addition, by mixing the aluminum nitride and the inorganic powder having a lipophilic group on the surface, the familiarity with the resin is improved as compared with the others, so that the dispersibility in the resin is also significantly improved.
[0025]
When using an inorganic powder having a lipophilic group on the surface as a fluidity improver, if an organic solvent is used as a dispersant during mixing, the water resistance is improved and the elution suppression of ionic components is suppressed compared to other methods. Is very big. The reason why the method of mixing an inorganic powder having a lipophilic group on the surface using a dispersant has an effect of improving water resistance and suppressing the elution of ionic components is unlike any other method. The lipophilic coating on the surface of the inorganic powder is eluted by the solvent, and the lipophilic coating covers the surface of the aluminum nitride so that the surface of the aluminum nitride is completely covered. It is speculated that the effects of improving water resistance and elution of ionic components will be greater than those that only exist. The same effect can be obtained regardless of what lipophilic coating agent is contained on the surface of the inorganic powder. In particular, an inorganic powder in which the surface of the inorganic powder is coated with silicon oil is useful. Any organic solvent can be used as the dispersant used here, and examples thereof include methanol, ethanol, isopropanol, butanol, and tetrahydroxyfuran (THF). Further, a water-insoluble organic solvent such as heptane, hexane, benzene, toluene or chloroform may be used in combination.
[0026]
The inorganic powder having a lipophilic group on the surface using a dispersant may be mixed at any time after the phosphoric acid compound treatment or at the time of the phosphoric acid compound treatment, and may be carried out whenever it can be uniformly mixed.
As a method of mixing after the treatment with a phosphoric acid compound, there is a method of mixing aluminum nitride powder or inorganic powder having a lipophilic group on the surface as a slurry, using a mixer, a ball mill, or the like.
[0027]
As a method of mixing in the treatment with the phosphoric acid compound, there are a method in which an inorganic powder having a lipophilic group on the surface is previously mixed with a dispersant in a slurry or paste form, and a surface in a phosphoric acid compound solution containing the dispersing agent. There is a method in which an inorganic powder having a lipophilic group is added as it is and mixed. The former requires a small amount of dispersant and can be produced at low cost. In particular, when an aluminum nitride powder is treated with an aqueous solution of an inorganic phosphoric acid such as orthophosphoric acid and an inorganic powder having a lipophilic group on the surface is used as a fluidity improver, an organic solvent is used as a dispersant for uniform mixing. It is necessary to make the fluidity improver into a slurry or paste.
[0028]
When the dispersant is not used, the fluidity improver may be mixed after the phosphoric acid compound treatment or at the time of the phosphoric acid compound treatment, as long as the fluidity improver can be uniformly mixed with the aluminum nitride powder.
As a method of mixing the fluidity improver after the phosphoric acid compound treatment, there are a method of mixing powders using a Henschel mixer, a V blender or the like, and a method of pulverizing and mixing using a ball mill. The latter method is more effective in improving performance.
[0029]
As a method of mixing the fluidity improver during the phosphoric acid compound treatment, a method of dispersing the aluminum nitride powder in the phosphoric acid compound solution and dispersing the fluidity improving agent in the slurry, a paste in which the aluminum nitride powder is kneaded into the phosphoric acid compound solution There are a method in which a fluidity improver is kneaded in a state, a method in which a fluidity improver is dispersed in a phosphoric acid compound solution in advance, and then an aluminum nitride powder is treated with a phosphoric acid compound. Further, the fluidity improver may be mixed in a slurry or paste form with a solvent.
[0030]
The aluminum nitride slurry that has been treated with the phosphoric acid compound and mixed with the fluidity improver is filtered, washed with water or an organic solvent, and then dried and pulverized to remove excess phosphoric acid compound. By repeating this filtration to drying, an aluminum nitride powder having higher purity fluidity and water resistance and low ionic component elution is obtained. In addition, any method such as a method of directly drying a slurry of aluminum nitride powder treated with a phosphoric acid compound and mixing a fluidity improver using spray drying, or a method of filtering and drying the cake as described above It doesn't matter.
For the filtration of the aluminum nitride slurry, a Nutsche, a centrifugal filter or the like is used. Moreover, you may dry as it is, without filtering.
[0031]
When a predetermined amount of phosphoric acid compound and fluidity improver are used to paste aluminum nitride powder into a paste, it is dried and pulverized as it has excellent fluidity and water resistance. An aluminum nitride powder with low elution can be obtained. By this method, it is possible to produce a large amount of aluminum nitride powder having excellent fluidity and water resistance and low elution of ionic components at low cost.
[0032]
As a drying method, the filtered cake, slurry or paste is dried at 80 to 300 ° C. for 3 to 24 hours. As the dryer to be used, a hot air dryer, a steam dryer or the like is preferably used.
[0033]
For the pulverization, a jet mill, a sample mill, a ball mill or the like is used. Moreover, the pulverization here is to make secondary particles into primary particles, and does not destroy the coating surface.
[0034]
With respect to the aluminum nitride powder having excellent fluidity and water resistance obtained by the above method and low elution of the ionic component, elution of the ionic component can be further suppressed by the following method. That is, as a method for suppressing elution of ionic components, a method of promoting the formation of aluminum phosphate bonds (Al—O—P) by heat treatment at 150 to 600 ° C. There is a method of removing. Moreover, elution of an ionic component can be effectively suppressed by combining heat treatment and cleaning. By using a method for suppressing the elution of these ionic components, an aluminum nitride powder that is further excellent in high-fluidity fluidity and water resistance and has low elution properties of the ionic components can be obtained.
[0035]
【Example】
Hereinafter, the present invention will be described with reference to examples. % And parts are expressed on a weight basis unless otherwise specified.
Example 1
To 56.8 parts of 2.4% orthophosphoric acid aqueous solution (1.4 parts of orthophosphoric acid and 55.4 parts of water), 2% water-repellent silica was added to aluminum nitride powder as a slurry with methanol, and orthophosphoric acid was added. Dispersed in an aqueous solution. Next, 100 parts of aluminum nitride powder (average particle size 1 μm) was added to the above orthophosphoric acid aqueous solution, kneaded with a 5 L kneader, and treated at 30 ° C. for 30 minutes. This mixture was dried at 120 ° C. for 8 hours, dried, and then pulverized with a jet mill to obtain aluminum nitride powder.
[0036]
The evaluation test of the obtained aluminum nitride powder was performed by the following method.
・ Phosphorus content on the surface of aluminum nitride powder
1.5 g of aluminum nitride powder was dissolved by heating in an aqueous sodium hydroxide solution, neutralized and then subjected to colorimetric analysis, and the phosphorus content on the surface of the water-resistant aluminum nitride powder was measured.
・ Water resistance test of aluminum nitride powder
100 g of pure water was heated to 100 ° C., 1 g of aluminum nitride powder was dispersed in pure water that reached 100 ° C., and the pH change of the dispersion after dispersion was measured over time.
・ Measurement of electrical conductivity
The dispersion subjected to the water resistance test was filtered, and the electrical conductivity of the filtrate was measured to evaluate the eluted ionic component.
・ Fluidity was also evaluated by measuring the angle of repose.
・ Elution test of aluminum nitride powder
100 g of pure water and 12.5 g of aluminum nitride powder were placed in a Teflon-coated stainless steel container, and the container was sealed. This was heated at 120 ° C. for 24 hours, cooled and then filtered, and the pH and electrical conductivity of the filtrate were measured.
These evaluation results are shown in Table 1.
[0037]
Examples 2-3
Aluminum nitride powder was obtained in the same manner as in Example 1 except that the amount of water-repellent silica added was changed to 5% and 10%.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0038]
Example 4
An aluminum nitride powder was prepared in the same manner as in Example 1 except that the 2.4% orthophosphoric acid aqueous solution was changed to 60.5 parts (orthophosphoric acid 4.1 parts, water 56.4 parts). Got.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0039]
Example 5
The aluminum nitride powder was prepared in the same manner as in Example 1 except that the 2.4% orthophosphoric acid aqueous solution was changed to 69.7 parts of the 15.8% orthophosphoric acid aqueous solution (11 parts of orthophosphoric acid and 58.7 parts of water). Obtained.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0040]
Examples 6-7
Aluminum nitride powder was obtained in the same manner as in Example 1 except that the fluidity improver was changed to alumina or boron nitride.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0041]
Example 8
Into a glass container having a capacity of 5 L, 230 parts of a 13% pyrophosphoric acid aqueous solution (30 parts of pyrophosphoric acid, 200 parts of water) are added, and 100 parts of aluminum nitride powder (average particle size 1 μm) is added to the aqueous pyrophosphoric acid solution and dispersed in the aqueous solution. Then, a treatment was performed at a treatment temperature of 80 ° C. for 15 minutes to obtain an aluminum nitride powder slurry. Further, 2% water-repellent silica was slurried with methanol in the aluminum nitride powder and dispersed in the aluminum nitride powder slurry. The slurry was filtered, washed with 200 parts of water to remove excess pyrophosphoric acid aqueous solution, dried at 120 ° C. for 3 hours, dried, and then pulverized with a jet mill to obtain aluminum nitride powder.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0042]
Example 9
In a glass container with a capacity of 5 L, 250 parts of isopropanol / pure water = 9/1 (weight ratio) and 30 parts of ethyl acid phosphate were mixed, and this mixture was mixed with aluminum nitride powder (average particle size 1 μm) 100. The mixture was dispersed for 30 minutes at a treatment temperature of 50 ° C. (aluminum nitride powder / ethyl acid phosphate / water = 100 parts / 30 parts / 25 parts). Further, 2% water-repellent silica was dispersed in the aluminum nitride powder. The slurry was filtered and washed with 1000 parts isopropanol to remove excess ethyl acid phosphate. This was dried at 80 ° C. for 5 hours and then pulverized with a jet mill to obtain an aluminum nitride powder.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0043]
Example 10
In a 5 L kneader, 56.8 parts of 2.4% orthophosphoric acid aqueous solution (1.4 parts of orthophosphoric acid, 55.4 parts of water) were added 100 parts of aluminum nitride powder (average particle size 1 μm), and kneaded into a paste. The treatment was performed at 30 ° C. for 30 minutes. This mixture was dried at 120 ° C. for 8 hours, dried, and then pulverized with a jet mill to obtain water-resistant aluminum nitride powder. Further, 2% of water-repellent silica was added to the water-resistant aluminum nitride powder, an alumina ball was put in a magnetic pot having a capacity of 1 L, and mixed and pulverized at 120 rpm for 1 hour to obtain an aluminum nitride powder. .
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0044]
Example 11
To 56.8 parts of 2.4% orthophosphoric acid aqueous solution (1.4 parts of orthophosphoric acid and 55.4 parts of water), 2% water-repellent silica was added to aluminum nitride powder as a slurry with methanol, and orthophosphoric acid was added. Dispersed in an aqueous solution. Next, 100 parts of aluminum nitride powder (average particle size 1 μm) was added to the above orthophosphoric acid aqueous solution, kneaded with a 5 L kneader, and treated at 30 ° C. for 30 minutes. This mixture was dried at 120 ° C. for 8 hours, further heat-treated at 300 ° C. for 5 hours, and then pulverized with a jet mill to obtain aluminum nitride powder.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0045]
Examples 12-13
Aluminum nitride powder was obtained in the same manner as in Example 11 except that the amount of water-repellent silica added was changed to 3% and 4%.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0046]
Examples 14-16
The aluminum nitride powder obtained in Examples 11 to 13 was washed with 100 ° C. pure water, filtered and dried, and then pulverized with a jet mill to obtain aluminum nitride powder.
The obtained aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0047]
Comparative Example 1
The same procedure as in Example 1 was performed except that the water-repellent silica in Example 1 was omitted.
[0048]
The obtained water-resistant aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0049]
Comparative Examples 2-3
The same procedure as in Example 1 was performed except that the water-repellent silica of Examples 4 and 5 was omitted.
The obtained water-resistant aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0050]
Comparative Example 4
An aluminum nitride powder was prepared in the same manner as in Example 1 except that the 2.4% orthophosphoric acid aqueous solution was changed to 77.1 parts of a 21.5% orthophosphoric acid aqueous solution (16.6 parts of orthophosphoric acid, 60.5 parts of water). Got.
The obtained water-resistant aluminum nitride powder was evaluated for phosphorus content, water resistance, eluted ionic components and fluidity in the same manner as in Example 1. The results are shown in Table 1.
[0051]
Examples 17-32
150 parts of alumina particles and silica particles and 100 parts of aluminum nitride powder obtained by the operations of Examples 1 to 16 were mixed with 100 parts of silicon resin, and kneaded for 10 minutes with a kneader to obtain an aluminum nitride-containing silicon resin A composition was obtained.
The resulting resin composition was extruded through a 150-mesh strainer, but no agglomerates were found that did not pass through the strainer.
[0052]
Comparative Examples 5-7
A silicon resin composition containing aluminum nitride was obtained in the same manner as in Example 17 except that the water-resistant aluminum nitride powder obtained by the operations of Comparative Examples 1 to 3 was used.
The obtained resin composition was extruded through a 150-mesh strainer, but aggregates that did not pass through the strainer were observed.
[0053]
[Table 1]

[0054]
【The invention's effect】
The aluminum nitride powder obtained by the present invention has very high water resistance, and can also suppress elution of ionic components. In addition, since excellent fluidity can be imparted and no aggregate is formed, it can be uniformly dispersed in the resin during kneading into the resin.
Further, it is useful as a filler for resin materials such as a sealing material for electronic components that require heat dissipation, an adhesive material for electronic components, and a molding material for laminated substrates. In addition, since the water resistance is very high and the ionic components are hardly eluted, the product can be used even under high temperature and humidity resistance, and a product with higher reliability than the prior art can be obtained.
Furthermore, when used as a structural material such as a high-temperature furnace material, even if an aqueous material is used as a binder at the time of molding, it does not hydrolyze so that the original characteristics of the aluminum nitride powder are not lost. That is, if the aluminum nitride powder of the present invention is used, it is not necessary to use a flammable and harmful organic solvent as a binder, and inexpensive water can be used. Can be manufactured.

Claims (6)

Containing silica having an oleophilic group on the surface as a fluidity improving agent, and a nitride of aluminum powder which has been treated with phosphoric acid compound, 0 phosphorescent acid compound in terms _of P ₂ O ₅ with respect to the aluminum nitride powder. An aluminum nitride powder having excellent fluidity and water resistance and low leaching of ionic components, characterized by containing 1 to 10% by weight.  The aluminum nitride powder according to claim 1, comprising an aluminum nitride powder treated with a phosphoric acid compound and a fluidity improver in the presence of water. The aluminum nitride powder according to any one of claims 1 and 2 , wherein the addition amount of the fluidity improver is 0.1 to 10 wt% with respect to the aluminum nitride powder or the water-resistant aluminum nitride powder. The aluminum nitride powder according to any one of claims 1 to 3, wherein the aluminum nitride powder is obtained by reacting an organoaluminum compound and ammonia. The aluminum nitride powder is treated with a phosphoric acid compound in the presence of water and mixed with silica having a lipophilic group on the surface as a fluidity improver. Method for producing a low aluminum nitride powder. In the presence of water, the aluminum nitride powder is treated with a phosphoric acid compound, added with a dispersant, and mixed with silica having a lipophilic group on the surface as a fluidity improver, excellent in fluidity and water resistance, A method for producing an aluminum nitride powder with low elution of ionic components.