JP2981002B2 - Aluminum nitride powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aluminum nitride (hereinafter sometimes referred to as "AlN") powder.

[0002]

2. Description of the Related Art Aluminum nitride is expected to be applied to electronic circuit components because it has high thermal conductivity and electrical insulation and has a thermal expansion coefficient close to that of a Si chip. However, aluminum nitride has extremely poor water resistance. Particularly, in the case of powder, aluminum nitride is gradually decomposed even in a state of being left in the air, generating ammonia and being transformed into aluminum hydroxide. For this reason, for example, when aluminum nitride powder is to be used as a filler for increasing the heat radiation of a resin, there is a problem in that such water resistance is very large.

Conventionally, in order to improve the water resistance of aluminum nitride, an organic polymer is coated on the surface of the aluminum nitride powder, or the surface of the aluminum nitride powder is oxidized to provide an aluminum oxide layer to form a protective film. Attempts have been made.

[0004]

In coating with an organic polymer or forming an aluminum oxide layer, sufficient water resistance cannot be obtained under severe conditions such as high temperature and high humidity. The present invention
An object is to provide an aluminum nitride powder having excellent water resistance.

[0005]

Means for Solving the Problems As a result of studying the above-mentioned improvements, the inventors have found that aluminum nitride powder having a film of an organosilicon compound described later exhibits unprecedented water resistance and chemical resistance. I found it. That is, the present invention provides an aluminum nitride powder having an organosilicon compound layer having a siloxane bond formed on the particle surface.

In the present invention, the organosilicon compound layer is formed of, for example, the following two types of coating compositions. The first coating composition is represented by the following general formula (I): R ¹ _n SiX _4-n (I) wherein R ¹ is the same or different, substituted or unsubstituted monovalent carbon having 1 to 8 carbon atoms. Represents a hydrogen group, n represents an integer of 0 to 3, and X represents a hydrolyzable group.) An oligomer solution of an organosilane obtained by partially hydrolyzing a hydrolyzable organosilane represented by the following formula: An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane in colloidal silica dispersed in an organic solvent and water (hereinafter, these may be referred to as “component (D)”) Is a main component. The component (D) is, for example, hydrolyzed, condensed or dealcoholized with a catalyst, and dried to form
An organosilicon compound having a siloxane bond, which forms a coating layer continuous with the surface layer of the AlN powder particles, is formed.

The second coating composition comprises: (A) an organosilane oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane represented by the above general formula (I) in an organic solvent; An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing degradable organosilane in colloidal silica dispersed in an organic solvent and water, (B) average composition formula (II) R ² _a Si (OH) _b O _{(4-ab) / 2} ... (II) (wherein, R ² represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and a and b each represent 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, a + b
It is a number that satisfies the relationship of <4. ), And a polyorganosiloxane containing a silanol group in the molecule, and (C) a catalyst. This coating composition undergoes, for example, hydrolysis, condensation, or dealcoholization condensation reaction, and further forms an organosilicon compound having a siloxane bond, which becomes a coating layer continuous with the AlN surface layer by drying.

The group R ¹ in the hydrolyzable organosilane represented by the general formula (I) represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, such as a methyl group and an ethyl group. , Propyl, butyl, pentyl, hexyl,
Alkyl groups such as heptyl group and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group;
Aralkyl groups such as -phenylethyl group, 2-phenylpropyl group and 3-phenylpropyl group; aryl groups such as phenyl group and tolyl group; alkenyl groups such as vinyl group and allyl group; chloromethyl group and γ-chloro Propyl group, halogen-substituted hydrocarbon group such as 3,3,3-trifluoropropyl group and γ-methacryloxypropyl group, γ
And substituted hydrocarbon groups such as -glycidoxypropyl group, 3,4-epoxycyclohexylethyl group and γ-mercaptopropyl group. Among them, the number of carbon atoms is 1 due to ease of synthesis or availability.
4 alkyl groups and phenyl groups are preferred.

[0009] X of the hydrolyzable group is an alkoxy group,
Examples include an acetoxy group, an oxime group (see the following formula 1), an enoxy group (see the following formula 2), an amino group, an aminooxy group (see the following formula 3), an amide group (see the following formula 4), and the like. An alkoxy group is preferred because of its availability and ease of preparing a silica-dispersed oligomer solution.

[0010]

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[0011]

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[0012]

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[0013]

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Examples of such hydrolyzable organosilanes include mono-, di-, tri- and tetra-functional alkoxysilanes wherein n in the general formula (I) is an integer of 0 to 3; Acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes,
Amidosilanes and the like. Alkoxysilanes are preferred because they are easily available and easy to prepare a silica-dispersed organosilane oligomer solution.

Particularly, tetramethoxysilane and tetraethoxysilane can be exemplified as the n = 0 tetraalkoxysilane, and methyltrimethoxysilane, methyltriethoxysilane and methyltriisosilane as the n = 1 organotrialkoxysilane. Propoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane can be exemplified. Examples of the diorganodialkoxysilane of n = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane, and the like. Examples thereof include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. Further, an organosilane compound generally called a silane coupling agent is also included in the alkoxysilanes.

When water-dispersible colloidal silica is used, water present as a component other than the solid content can be used for hydrolyzing the organosilicon compound (A). These are usually made from water glass, but such colloidal silica is readily available commercially. The organic solvent-dispersed colloidal silica can be easily prepared by replacing water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersed colloidal silica can be easily obtained as a commercial product similarly to the water-dispersed colloidal silica. The type of the organic solvent in which the colloidal silica is dispersed is, for example, methanol, ethanol, isopropanol (also referred to as IPA), n-
Lower aliphatic alcohols such as butanol and isobutanol; ethylene glycol derivatives such as ethylene glycol, ethylene glycol monobutyl ether and ethylene glycol monoethyl ether; derivatives of diethylene glycol such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol And one selected from the group consisting of
One or more species can be used. In combination with these hydrophilic organic solvents, toluene, xylene,
Ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can also be used.

The amount of water used is preferably 0.001 to 0.5 mol of water per 1 mol of the hydrolyzable group (X). If the ratio is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and if it exceeds 0.5 mol, the stability of the partial hydrolyzate may be deteriorated. The method of partial hydrolysis is not particularly limited. For example, a hydrolyzable organosilane and colloidal silica may be mixed and a necessary amount of water may be added and blended. At this time, the partial hydrolysis reaction proceeds at room temperature. 60-100 ° C to promote partial hydrolysis reaction
May be heated. For the purpose of further promoting the partial hydrolysis reaction, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid,
Organic acids and inorganic acids such as malonic acid, toluenesulfonic acid, and oxalic acid may be used as the catalyst.

When a coating layer is formed on the AlN surface only with the component (D), it is preferable to prepare the terminal with at least 80% or more of a hydrolyzable group, and to prepare the above-mentioned oligomer (or prepolymer). In preparing the catalyst, for example, an acidic catalyst, (C ₅ H ₅ ) _n
One or more compounds selected from MeZ _4-n , aminosilane, quaternary ammonium salts of inorganic or organic acids, amine salts of inorganic or organic acids, and organic tin compounds are used.

A catalyst and water are used to prepare a coating solution as described above. The degree of hydrolysis and condensation varies depending on the amount of water used. The addition amount of water is preferably 1 wt% or more and 20 wt% or less based on the silicon alkoxide. 1wt
%, The film may not be formed, and if it is more than 20% by weight, curing may take a long time or curing may be insufficient.

The catalyst used includes organic and inorganic acids, for example, formic acid, acetic acid, oxalic acid, chloroacetic acid,
Dilute solutions such as hydrochloric acid, phosphoric acid, and sulfuric acid can be used. Examples of (C ₅ H ₅ ) _n MeZ _4-n (where n = 1, 2, or 3, Me is an element belonging to Group IV of the Periodic Table, Groups 4 to 6, and Z is a halogen element) , Dicyclopentadienyl zirconium dichloride, dicyclopentadienyl titanium dichloride and the like. Examples of the aminosilane include γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and N- (β-aminoethyl) -γ-aminopropyltrimethyldimethoxysilane. . As quaternary ammonium salts and amine salts of inorganic acids and organic acids, for example, inorganic acids such as hydrochloric acid,
Salts of organic acids such as formic acid and acetic acid, such as ammonia, trimethylamine, triethylamine, and n-butylamine are exemplified. Examples of the organotin compound include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, and the like.

It is preferable that 50 mol% or more of the hydrolyzable organosilane represented by the general formula (I) is a trifunctional compound represented by n = 1, more preferably 6
It is at least 0 mol%, most preferably at least 70 mol%. If this is less than 50 mol% , the dry curability may be poor. The colloidal silica in the component (A) is used as needed to enhance the smoothness of the coating composition used in the present invention. As such colloidal silica, water-dispersible or non-aqueous organic solvent-dispersible colloidal silica such as alcohol can be used. Generally, such colloidal silica contains 20 to 50% by weight of silica as a solid content, and the amount of silica can be determined from this value. When using water-dispersible colloidal silica,
Water present as a component other than the solid content can be used for hydrolysis of the organosilicon compound as the component (A). These are usually made from water glass, but such colloidal silica is readily available commercially.

When the component (A) contains colloidal silica, the silica content is preferably 5 to 95% by weight.
It is contained in the range. More preferably, it is in the range of 10 to 90% by weight, most preferably 20 to 85% by weight. If the content is less than 5% by weight, desired smoothness cannot be obtained,
If it exceeds 95% by weight, it becomes difficult to uniformly disperse the silica, and the component (A) may cause inconvenience such as gelation.

The component (II) such as when a coating layer is formed with the components of the above formulas (I) and (II), ie, the silanol group-containing polyorganosiloxane of the component (B) is a feature of the present invention. It is an important ingredient to make. The component (B) has an average compositional formula of R ² _a Si (OH) _b O _{(4-ab) / 2} ... (II) (wherein, R ² is the same or different and has a substituted or unsubstituted carbon number of 1) And a and b represent 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. ).
In the formula, R ² is the same as R ¹ in the above (I), preferably an alkyl group having 1 to 4 carbon atoms, phenyl group, vinyl group, γ-glycidoxypropyl group, γ
-Methacryloxypropyl group, γ-aminopropyl group,
Substituted hydrocarbon groups such as 3,3,3-trifluoropropyl group, more preferably methyl group and phenyl group. Further, in the formulas, a and b are numbers that satisfy the above relationship, and if a is less than 0.2 or b exceeds 3, there is a problem that cracks occur in the cured film, and
When a is more than 2 and 4 or less, or when b is less than 0.0001, curing does not proceed well.

As such a silanol group-containing polyorganosiloxane, for example, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or one or a mixture of two or more alkoxysilanes corresponding thereto are known. Can be obtained by hydrolyzing with a large amount of water according to the method described above. When a silanol group-containing polyorganosiloxane is hydrolyzed by a known method using alkoxysilane, a small amount of an unhydrolyzed alkoxy group may remain. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but in the present invention, such a polyorganosiloxane may be used.

The curing catalyst which is the component (C) of the present invention promotes the condensation reaction between the components (A) and (B) to cure the coating. Such catalysts include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate, dioctyltin dimaleate; dibutylamine-2-hexoate;
Amine salts such as dimethylamine acetate and ethanolamine acetate; quaternary ammonium salts of carboxylic acids such as tetramethylammonium acetate; amines such as tetraethylpentamine; N-β-aminoethyl-γ-aminopropyltrimethoxysilane; Amine-based silane coupling agents such as N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane; p-toluenesulfonic acid;
Acids such as phthalic acid and hydrochloric acid; aluminum alkoxides;
Aluminum compounds such as aluminum chelates; alkali catalysts such as potassium hydroxide; titanium compounds such as tetraisopropyl titanate, tetrabutyl titanate, titanium tetraacetylacetonate; halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylmonochlorosilane, etc. However, there is no particular limitation as long as it is effective for the condensation reaction with the components (A) and (B) in addition to the catalyst.

The mixing ratio of component (A) and component (B) is such that 1 to 99 parts by weight of component (A) and component (B) 99
To 1 part by weight, more preferably the component (A) 5
95 to 5 parts by weight of component (B), most preferably 90 to 10 parts by weight of component (B) to 10 to 90 parts by weight of component (A). (The total of the component (B) is 100 parts by weight.) Component (A) is inferior in cold-curing is less than 1 part by weight, hand, 99
If the amount is more than 10 parts by weight, the curability may be unstable and a good coating film may not be obtained.

The amount of the component (C) added is 0.0001 with respect to 100 parts by weight of the total of the components (A) and (B).
It is preferably from 10 to 10 parts by weight. It is more preferably 0.0005 to 8 parts by weight, most preferably 0.05 to 8 parts by weight.
007 to 5 parts by weight. If it is less than 0.0001 part by weight, it may not be cured at room temperature, and if it exceeds 10 parts by weight, heat resistance may be deteriorated.

The formation of a film on the surface of the aluminum nitride powder is performed, for example, as follows, but is not limited to this method. The coating composition (or coating material) is mixed with aluminum nitride powder and adhered to the particle surface of the powder. In this state, a treatment for curing is performed to form a film on the particle surface. The treatment temperature of the coating agent may be appropriately set to a temperature at which a continuous coating layer can be formed on the surface of the aluminum nitride powder by, for example, hydrolysis, condensation or dealcoholization condensation reaction, and drying (for example, normal temperature or heating temperature).

The aluminum nitride powder having an organosilicon compound layer on the particle surface obtained in this manner has been found to have significant improvements in water resistance and chemical resistance, and can be used under high temperature and high humidity. . The thickness of the organosilicon compound layer (coating) having a siloxane bond is not particularly limited, but is preferably 1 μm or less in order to secure general water resistance, and depending on the application, a thickness of about 2 μm is required. However, a thickness greater than this is not preferable because it significantly impairs the high thermal conductivity of the aluminum nitride powder.

In the present invention, for example, as shown in FIG. 1, an organosilicon compound coating layer 2 is formed on the entire surface of particles 1 of aluminum nitride powder. Forming on the entire surface of the particles is more preferable than forming on a part of the surface in terms of water resistance and chemical resistance.

[0031]

Since the organosilicon compound layer having a siloxane bond is formed on the surface of the aluminum nitride powder, the powder has high water resistance, high alkali resistance and heat resistance.

[0032]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples. Hereinafter, all “parts” represent “parts by weight” and all “%” represent “% by weight”. First, an example of a method for preparing the component (A) will be described. (Preparation Example A-1) IPA-ST was placed in a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer.
100 parts of (isopropanol-dispersed colloidal silica sol: particle diameter 10 to 20 μm, solid content 30%, H ₂ O 0.5%, manufactured by Nissan Chemical Industries, Ltd.), methyltrimethoxysilane 6
8 parts, 18 parts of dimethyldimethoxysilane, 2.7 parts of water and 0.1 part of acetic anhydride were added, and a partial hydrolysis reaction was carried out at a temperature of 80 ° C. for about 3 hours while stirring, followed by cooling (A) The components were obtained. This had a solid content of 36% when left at room temperature for 48 hours. The component (A) obtained here is referred to as A-1. The conditions for preparing A-1 were as follows. The number of moles of water based on 1 mole of the hydrolyzable group: 1 × 10 ^−1. The silica content of the component (A): 40.2%. The mole% of the n = 1 hydrolyzable organosilane: 77 mole%. (Preparation Example A-2) IPA-ST was placed in a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer.
100 parts of (isopropanol-dispersed colloidal silica sol: particle diameter 10 to 20 μm, solid content 30%, H ₂ O 0.5%, manufactured by Nissan Chemical Industries) 100 parts, methyltrimethoxysilane 68
Parts, phenyltrimethoxysilane 49.5 parts, water 7.7
Partial hydrolysis reaction was carried out at a temperature of 65 ° C. for about 5 hours with stirring, and the mixture was cooled to obtain the component (A).
It has a solid content of 3 when left at room temperature for 48 hours.
6%. The component (A) obtained here is referred to as A-2. The conditions for preparing A-2 were as follows. Number of moles of water per mole of hydrolyzable group: 2 × 10 ^−1. Silica content of component (A): 31.3%. Mole% of n = 1 hydrolyzable organosilane: 100
Next, an example of a method for preparing the component (B) will be described. (Preparation Example B-1) A mixed solution of 220 parts (1 mol) of methyltriisopropoxysilane and 150 parts of toluene was weighed and placed in a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel, and a thermometer. Hydrochloric acid aqueous solution 1
08 parts was added dropwise to the above mixture in 20 minutes to hydrolyze methyltripropoxysilane. After 40 minutes from the dropping, stirring was stopped, and a lower layer of a mixed solution of water and isopropyl alcohol containing a small amount of hydrochloric acid separated into two layers was separated. Then, the remaining hydrochloric acid in the resin solution of toluene was removed by washing with water. After the toluene was removed under reduced pressure, the residue was diluted with isopropyl alcohol to obtain a 40% solution of a silanol group-containing organopolysiloxane having an average molecular weight of about 2,000 in isopropyl alcohol.
This is called B-1. The molecular weight was measured by GPC (gel permeation chromatography) using a measurement model name HLC-802UR (manufactured by Tosoh Corporation).
A calibration curve was prepared using standard polystyrene and measured. The subsequent molecular weight was measured in the same manner. (Preparation Example B-2) Water 1 was added to a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel and a thermometer.
000 parts and 50 parts of acetone were weighed, and 44.8 parts (0.3 mol) of methyltrichlorosilane, 38.7 parts (0.3 mol) of dimethyldichlorosilane, and 84.6 parts of phenyltrichlorosilane were mixed in the mixed solution. A part (0.4 mol) dissolved in 200 parts of toluene was hydrolyzed while dripping under stirring. After 40 minutes, the stirring was stopped, and the reaction solution was transferred to a separating funnel and allowed to stand. Then, the hydrochloric acid aqueous solution of the lower layer separated into two layers was separated and removed, and then the toluene solution of the organopolysiloxane of the upper layer was added to the toluene solution. The remaining water and hydrochloric acid were removed by stripping off the excess toluene by vacuum stripping together with excess toluene to obtain a 60% toluene solution of a silanol group-containing organopolysiloxane having an average molecular weight of about 3000. This is called B-2.

Examples 1 to 3 These examples are examples in which a coating composition containing the components (A), (B) and (C) as essential components is used. After mixing the components (A), (B) and (C) in the composition shown in Table 1, 10 parts of AlN powder was added to 100 parts of the coating liquid diluted 5 times with toluene. After stirring at 200 rpm for 1 hour, the mixture was filtered by suction. Thereafter, the filtered AlN powder was washed with toluene, filtered by suction, and dried at 100 ° C. for 30 minutes to obtain a treated powder (a powder having an organosilicon compound layer on the entire surface of the AlN powder particles). The AlN powder used had a specific surface area of 2.5 m ² / g. The aluminum nitride powders thus obtained were respectively (1) -1 and (1)
-2, (1) -3. The thickness of the coating layer is
1.0 μm [(1) -1] and 0.7 μm, respectively
[(1) -2] and 1.5 μm [(1) -3].

[0034]

[Table 1]

Example 4 This is because an organosilicon compound containing the component (D) as a main component was continuously hydrolyzed, condensed or de-alcoholized in the presence of a catalyst and a curing agent, and dried on the surface of AlN particles. It is an example in the case of forming an organosilicon compound coating layer. In a flask equipped with a stirrer, 100 parts of methyltrimethoxysilane, 105 parts of isopropanol-dispersed silica sol (manufactured by Catalyst Chemical Industry Co., Ltd., SiO ₂ content: 30%), 20 parts of tetraethoxysilane, 30 parts of dimethyldimethoxysilane, 100 parts of isopropanol
Part, 100 ppm of HC based on the solid content of the coating liquid
3% water was added to 1 and the silicon alkoxide. These were stirred at 25 ° C for 30 minutes, and sealed at 25 ° C for 1 minute.
Saved for months. Then, it was used as a coating material.

The coating material 1 thus obtained
To 100 parts, 10 parts of AlN powder was added, and 2 parts were added in an open system.
The mixture was stirred at 5 ° C at 200 to 300 rpm for 1 hour. afterwards,
Suction filtration was performed. After washing the filtered powder with IPA,
After suction filtration and drying at 50 ° C. for 30 minutes, the treated powder (Al
A powder having an organosilicon compound layer on the entire surface of the N powder was obtained. The same AlN powder as in Examples 1 to 3 was used. The powder thus obtained is referred to as (2) -1. The thickness of the coating layer is 0.5 μm
Met.

Comparative Example 1 The aluminum nitride powder used in the above examples was subjected to the following test without any treatment. Comparative Example 2 800 ° C. in the presence of oxygen without coating the aluminum nitride powder used in the above Examples with an organosilicon compound
For 30 minutes to form an aluminum oxide layer on the surface. The thickness of the aluminum oxide layer was 0.7 μm.

Comparative Example 3 In Example 1, the acrylic resin (product number DL-967) manufactured by Dainippon Ink and Chemicals, Inc. (DIC) was coated with a two-fold dilution with toluene.
An aluminum nitride powder having an organic resin coating layer on the surface was obtained in the same manner as in Example 1 except that butanol was used as a washing solvent and drying was performed at 100 ° C. after coating. The average thickness of the organic resin coating layer was 3 μm.

The water resistance of the aluminum nitride powder obtained in Examples 1 to 4 and the untreated product (Comparative Example 1) were evaluated.
The water resistance was evaluated by dispersing the powder in water at room temperature and determining the time required for the temporal change in pH to become +0.5 from the initial value (initial pH value). The results are shown in Table 2.

[0040]

[Table 2]

The chemical resistance of the treated and untreated aluminum nitride powders of Examples 1-4 and Comparative Examples 1-3 was examined. A change in weight after holding the powder in a sodium hydroxide aqueous solution adjusted to pH 10 at room temperature for 24 hours before the holding was examined. The results are shown in Table 3.

[0042]

[Table 3]

As shown in Table 3, the weight of the treated AlN powder of the example did not change, whereas that of the comparative example showed a change in weight.

[0044]

According to the present invention, an aluminum nitride powder having excellent water resistance and alkali resistance and having heat resistance is provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one embodiment of an aluminum nitride powder of the present invention.

[Explanation of symbols]

 1 Particles of aluminum nitride powder 2 Organosilicon compound layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C01B 21/072 CA (STN)

Claims (3)

(57) [Claims] An organosilicon compound having a siloxane bond.
Object layer be formed on the particle surface, the organic silicon compound layer, in the general formula _{^{(I) R 1 n SiX 4}} -n ... (I) ( wherein, R ¹ represents a substituted or unsubstituted, identical or different Represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, n represents an integer of 0 to 3, and X represents a hydrolyzable group.) oligomer solution of comprising organosilane or the hydrolyzable organosilane obtained by partial hydrolysis in an organic solvent and colloidal silica dispersed in water, the aluminum nitride is made of silica-dispersed oligomer solution of organosilane powder, . 2. An organosilicon compound having a siloxane bond.
Object layer be formed on the particle surface, the organic silicon compound layer, (A) In the general formula _{^{(I) R 1 n SiX 4}} -n ... (I) ( wherein, R ¹ represents a substituted or identical or different Represents an unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, n represents an integer of 0 to 3, and X represents a hydrolyzable group.) (B) average: an organosilane oligomer solution obtained by decomposition or an organosilane silica dispersion oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane in colloidal silica dispersed in an organic solvent and water. Composition formula (II) R ² _a Si (OH) _b O _{(4-ab) / 2} (II) (wherein, R ² is the same or different and is a substituted or unsubstituted monovalent carbon having 1 to 8 carbon atoms.) A and b represent 0.2 ≦ a ≦ 2 and 0.000, respectively; 1 ≦ b ≦ 3, a + b
It is a number that satisfies the relationship of <4. ) Represented by, polyorganosiloxanes containing silanol groups in the molecule, and, Tei made from the coating composition as essential components (C) catalyst
Aluminum nitride powder that. Wherein the aluminum nitride powder according to claim 1 or 2, the organosilicon compound layer has a thickness of less than 2 [mu] m.