JP6378315B2 - Aluminum nitride powder with excellent water resistance - Google Patents

Description

  The present invention relates to an aluminum nitride powder excellent in water resistance, and more specifically, to a surface treatment agent used for obtaining such an aluminum nitride and a heat dissipation composite material including the aluminum nitride powder. Related.

In recent years, with the increase in power density of semiconductor devices, more advanced heat dissipation characteristics are required for heat dissipation materials. As a material that realizes heat dissipation of the device, there is a material called a thermal interface material, and the amount of use is rapidly expanding.
The thermal interface material is a material for relaxing the thermal resistance of the path through which the heat generated by the semiconductor element is released to the heat sink or housing, etc., in various forms such as sheets, gels, grease, heat dissipation boards, and semiconductor encapsulants. Is used. Generally, this thermal interface material is a composite material in which a thermally conductive filler is dispersed in a resin such as epoxy or silicone, and silica or alumina is often used as the filler. However, the thermal conductivities of silica and alumina are about 1 W / mK and 30 W / mK, respectively, and even in a composite material using alumina, the thermal conductivity remains at about 1 to 3 W / mK.

  However, as described above, due to the recent increase in power density of semiconductor devices, higher thermal conductivity has been required for thermal interface materials.

Therefore, in recent years, thermal interface materials using aluminum nitride having a high thermal conductivity as a filler are being developed. However, aluminum nitride has a problem that its surface reacts with water and hydrolyzes. As a means for solving such a problem, Patent Document 1 has an aluminum oxide film or a phosphate-based film. A method of treating aluminum nitride powder with an organosilicon coupling agent, an organophosphate coupling agent, or a phosphate group-containing organotitanium coupling agent has been proposed.
Patent Document 2 proposes a method of treating aluminum nitride powder with phosphoric acid, a metal salt of phosphoric acid, or organic phosphoric acid having an organic group having 12 or less carbon atoms.

However, these treatments cannot sufficiently improve the water resistance of aluminum nitride, and particularly satisfy the high water resistance required for applications such as a heat dissipation substrate and a semiconductor encapsulant in which a circuit and a resin are in direct contact. I can't. For example, if the treatment agent is used in a large amount, the water resistance can be greatly improved, but in this case, the characteristics essentially required for aluminum nitride such as thermal conductivity are deteriorated.
In addition, when aluminum nitride powder treated with a phosphorus-based compound such as phosphoric acid is used as the treating agent, there is a concern about corrosiveness to the circuit, so that the elution amount is required to be as low as possible. ing.
Furthermore, aluminum nitride has a problem with the affinity with the resin, and since the viscosity becomes too high when mixed with the resin, a large amount of aluminum nitride cannot be blended with the resin, and there are voids between the resin and the resin. It occurs, and there is a problem that the thermal conductivity does not increase.

JP-A-7-33415 WO2012 / 147999

Accordingly, an object of the present invention is to provide an aluminum nitride powder that not only exhibits excellent water resistance by surface treatment with a phosphorus compound, but also suppresses elution of phosphorus and effectively avoids a decrease in thermal conductivity due to the surface treatment. Is to provide.
Another object of the present invention is to provide an aluminum nitride powder in which thickening is effectively suppressed when blended with a resin.
Still another object of the present invention is to provide a surface treatment agent used for obtaining the above aluminum nitride powder and a composite material for heat dissipation which contains the above aluminum nitride powder and has high thermal conductivity. It is in.

  As a result of intensive studies to achieve the above object, the present inventors have surface-treated aluminum nitride powder with alkylphosphonic acid so that the carbon content is within a certain range, thereby improving water resistance. At the same time, the elution amount of phosphorus can be suppressed and the decrease in thermal conductivity due to the surface treatment can be effectively suppressed. In particular, the longer the alkyl group of the alkylphosphonic acid used, the higher the water resistance. It has been found that the amount of phosphorus elution can be further reduced and the amount of phosphorus eluted can be suppressed, and the present invention has been completed.

  According to the present invention, there is provided an aluminum nitride powder surface-treated with an alkylphosphonic acid and containing carbon in an amount of 0.4 to 2.0% by mass.

The aluminum nitride powder of the present invention is
(1) 1 g of the aluminum nitride powder is immersed in 50 g of ion exchange water, and the amount of phosphorus eluted when kept in a sealed container at 120 ° C. for 24 hours is suppressed to 5 ppm or less,
(2) When 2 g of the aluminum nitride powder is immersed in 100 g of ion-exchanged water and kept at 120 ° C. in a sealed container, the water resistance time indicated by the time when the pH reaches 10 is 6 hours or more,
In particular, it is preferable that the water resistance is further improved by adjusting the carbon number of the alkyl group of the alkylphosphonic acid used, for example,
(3) The water resistant time is 2 days or more,
Moreover,
(4) The water resistant time is 5 days or more,
Is preferred.

According to the present invention, there is also provided a surface treating agent for aluminum nitride powder comprising alkylphosphonic acid.
In such a surface treatment agent,
(5) The alkyl group of the alkylphosphonic acid has 10 to 30 carbon atoms, particularly 14 to 30 carbon atoms,
Is preferred.
According to the present invention, there is further provided a heat-dissipating composite material comprising the aforementioned aluminum nitride powder and a resin.

  The aluminum nitride (AlN) powder of the present invention surface-treated with an alkylphosphonic acid exhibits excellent water resistance, and as shown in Examples described later, 2 g of this AlN powder is converted into 100 g of ion-exchanged water. When the water resistance time indicated by the time to reach pH 10 is 6 hours or more when the temperature is kept at 120 ° C. in a sealed container, the carbon number of the alkyl group of the alkylphosphonic acid is increased. The water resistant time can be 2 days or more, and further 5 days or more.

  Moreover, although the AlN powder of the present invention is surface-treated with alkylphosphonic acid, phosphorus elution is effectively suppressed. For example, when 1 g of this AlN powder is immersed in 50 g of ion exchange water and kept in a sealed container at 120 ° C. for 24 hours, the elution amount of phosphorus is suppressed to 5 ppm or less, and the carbon of the alkyl group of the alkylphosphonic acid By increasing the number, the phosphorus elution amount can be suppressed to 4 ppm or less, and further to 3 ppm or less.

  Furthermore, in the present invention, since the treatment amount of alkylphosphonic acid is small (the carbon content of the AlN powder is 0.4 to 2.0% by mass), the thermal conductivity decreases due to the surface treatment or the viscosity increases when blended in a resin. Can also be effectively suppressed.

  Therefore, the AlN powder of the present invention can be mixed with a resin to impart high thermal conductivity as a heat dissipation composite material, hydrolysis due to moisture is effectively suppressed, and high thermal conductivity is stable over a long period of time. In addition, the circuit corrosion due to phosphorus elution is effectively prevented.

<Raw material aluminum nitride powder>
The AlN powder of the present invention is obtained by surface treatment using an alkylphosphonic acid, but the AlN powder used for this surface treatment (that is, the raw material AlN powder) is not particularly limited and is known aluminum nitride. Powder is used.
As a method for producing AlN used as a raw material, there are a direct nitriding method, a reductive nitriding method, a gas phase synthesis method, and the like. In the present invention, the raw material AlN powder can be produced by any method. .
Further, such raw material AlN powder may have an aluminum oxide layer formed on the particle surface, and the formation of the aluminum oxide layer is suitable for obtaining good water resistance.

For example, in the reduction nitriding method, it is essential to remove residual carbon in an oxidation step subsequent to the nitriding step, and an aluminum oxide layer can be formed during this step. Is formed. Can be formed.
In the direct nitridation method and the gas phase synthesis method, there is a pulverization step after the nitridation step, and the newly generated surface reacts with oxygen in the atmosphere to form an aluminum oxide layer. However, the aluminum oxide layer thus formed may not be sufficient to obtain high water resistance. In such a case, the aluminum oxide layer may be left by leaving the ground aluminum nitride powder in the atmosphere. It is also possible to form Furthermore, as a preferable method of forming the aluminum oxide layer, the desired aluminum oxide layer is formed by heating the pulverized aluminum nitride powder in an oxygen-containing atmosphere at 400 ° C. to 1000 ° C., preferably 500 ° C. to 900 ° C. It is possible to form.

<Alkylphosphonic acid>
In the present invention, alkylphosphonic acid is used as a surface treatment agent.
This alkylphosphonic acid has the following formula (1);
R—P (═O) (OH) ₂ (1)
Where
R is an alkyl group,
And the alkyl group R may be linear or branched.

  Examples of such alkylphosphonic acids include propylphosphonic acid, butylphosphonic acid, pentylphosphonic acid, hexylphosphonic acid, heptylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, undecylphosphonic acid, dodecylphosphonic acid. Acid, tridecylphosphonic acid, tetradecylphosphonic acid, pentadecylphosphonic acid, hexadecylphosphonic acid, heptadecylphosphonic acid, octadecylphosphonic acid, nonadecylphosphonic acid, icosylphosphonic acid, heicosylphosphonic acid, docosylphosphonic acid, Examples include tricosylphosphonic acid, tetracosylphosphonic acid, pentacosylphosphonic acid, hexacosylphosphonic acid, heptacosylphosphonic acid, octacosylphosphonic acid, and the like.

  In the present invention, among the above alkylsulfonic acids, regardless of whether the alkyl group R is linear or branched, the carbon number thereof is 10 to 30, particularly 14 to 30, and optimally 14 It is preferable to be in the range of -20.

  That is, the longer the carbon number of the alkyl group R, the more the water resistance can be improved and the phosphorus elution amount can be reduced. For example, when the surface treatment is performed using alkylphosphonic acid having an alkyl carbon number of about 4 to 8, the water resistance measured by the above-described method is 6 hours or more, particularly about 6 hours to 1 day. The phosphorus elution amount measured by the method can be suppressed to 5 ppm or less. However, when surface treatment is performed using an alkylphosphonic acid having an alkyl group with 10 or more carbon atoms, the water resistance time is improved to 2 days or more, the phosphorus elution amount is reduced to 4 ppm or less, and the carbon of the alkyl group is further reduced. When surface treatment is performed using an alkylphosphonic acid having a number of 14 or more, the water resistance time is further improved to 5 days or more, and the phosphorus elution amount is further greatly reduced to 3 ppm or less. Actually, according to the experimental results of Examples described later (see Table 1), the alkyl group has 16 or more carbon atoms and the water resistance time is 6 days or more, and when the carbon number is 18 or more, the water resistance time is 11 days or more. It can be seen that the elution amount of phosphorus is extremely reduced to 2 ppm or less.

The present inventors presume that such a phenomenon may be caused by the fact that if the alkyl chain is too short, water easily enters the interface between AlN and alkylphosphonic acid, making it difficult to obtain high water resistance. ing.
That is, the penetration of water not only lowers the water resistance, but also facilitates the elimination of alkylphosphonic acid from the AlN surface, resulting in an increase in the amount of phosphorus eluted. However, when the number of carbon atoms increases and the alkyl chain becomes longer, it becomes difficult for water to enter the interface between AlN and alkylphosphonic acid. As a result, water resistance is improved and phosphorus elution is kept low. It seems to be possible.

In addition, if the carbon number of the alkyl group R of the alkylphosphonic acid is longer than necessary, the thermal conductivity is lowered, and for example, it tends to be difficult to develop high thermal conductivity by mixing with a resin. There is.
That is, as understood from the fact that the thermal conductivity of a general organic substance is much lower than that of AlN, the longer the alkyl chain, the larger the coating thickness of the organic substance (alkyl group) on the AlN surface. The present inventors infer that the thermal resistance at the interface between the AlN particles and the resin also increases.

  Therefore, in the present invention, it is preferable that the number of carbon atoms of the alkyl group R of the alkylphosphonic acid is in the above range in terms of improving water resistance, suppressing phosphorus elution, and ensuring higher thermal conductivity. It becomes.

The phenomenon that the carbon number of the alkyl group of the alkylphosphonic acid used as the surface treatment agent has an effect on water resistance and phosphorus elution does not apply to phosphate compounds such as phosphate esters. For example, when surface treatment is performed using a phosphate ester, only a water resistance time of about one day can be obtained, and further, the phosphorus elution amount cannot be suppressed to 5 ppm or less. This has confirmed that it is the same, even if it lengthens carbon number of the alkyl group which a phosphoric acid type compound has (refer the comparative examples 7-9 mentioned later).
The difference between such phosphoric acid compounds and alkylphosphonic acids is not clearly elucidated, but the phosphoric acid system supported on the AlN surface is probably due to the catalytic action of the basic point present on the AlN surface. Although the compound is hydrolyzed by the presence of a slight amount of water, such a difference is considered to occur because alkylphosphonic acid hardly causes such hydrolysis.

<Surface treatment with alkylphosphonic acid>
The surface treatment of the raw material AlN powder using the alkylphosphonic acid described above can be carried out by bringing this powder into contact with alkylphosphonic acid by a dry method or a wet method.

The amount of the alkylphosphonic acid used for the surface treatment is such that the carbon content in the finally obtained surface-treated aluminum nitride powder is in the range of 0.4 to 2.0 mass%, particularly 0.5 to 1.8 mass%. Thus, it is appropriately set according to the contact method (dry method and wet method) to be employed, contact conditions, and the like.
That is, when the carbon content in the obtained surface-treated AlN powder is less than the above range, good water resistance cannot be obtained, and when it is more than the above range, when the surface-treated AlN powder is dispersed in the resin. The thermal conductivity of the composite material may be reduced.

The above carbon content is determined by calcining the powder before the surface treatment and the powder after the surface treatment in an oxygen stream, and quantifying the carbon content using the carbon analyzer from the amount of generated CO and CO ₂ gas. (See the examples for detailed conditions).

  It is possible to use a mixture of two or more types of alkylphosphonic acids for this surface treatment, but as described above, the longer the alkyl chain of the alkylphosphonic acid, the higher the water resistance. Therefore, when using a plurality of alkylphosphonic acids, it is desirable to reduce the amount of the alkyl chain having a short alkyl chain. For example, the amount of the alkylphosphonic acid having an alkyl group having 8 or less carbon atoms can be When the amount is 100 parts by mass, it is preferably 30 parts by weight or less, particularly 20 parts by weight or less.

By the way, in the dry method, the surface treatment is performed by mixing the raw material AlN powder and the alkylphosphonic acid in the absence of a solvent. In the wet method, the raw material powder and the alkylphosphonic acid are mixed in a predetermined solvent, and the obtained dispersion is dried.
Generally, surface treatment is performed by a wet method. This is because the surface treatment can be performed uniformly by using a small amount of alkylphosphonic acid, which is industrially advantageous.

When performing surface treatment by a wet method, the solvent to be used is not particularly limited as long as it does not adversely affect the surface treatment. In general, the following are used alone or in the form of a mixed solvent in which two or more kinds are mixed. Are preferably used.
water;
Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol;
Esters such as methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate;
Ketones such as acetone and methyl ethyl ketone;
Dioxane, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Ethers such as ethers;
Halogen-containing compounds such as methylene chloride and chloroform;

  Although the usage-amount of the said solvent is not restrict | limited in particular, Generally, it is 70-300 mass parts per 100 mass parts of raw material AlN powder, Especially 80-200 mass parts.

  The contact between the raw material AlN powder and the alkylphosphonic acid under the above-mentioned solvent is, for example, by adding the raw material AlN powder into the solvent and stirring to form a slurry, adding the alkylphosphonic acid to this, and mixing and stirring. It can also be performed by adding AlN powder and alkylphosphonic acid to the solvent and mixing and stirring. Furthermore, the raw material AlN powder is added to the solvent solution of alkylphosphonic acid and mixed. You can also

  When the raw material aluminum powder and the alkylsulfonic acid are mixed and dispersed in a solvent and brought into contact with each other as described above, the ratio of the median diameter / primary particle diameter of the AlN powder is 5.0 or less, particularly 4 It is preferable to mix and disperse under strong stirring conditions so as to be 0.0 or less, and most preferably 3.0 or less.

The median diameter is a particle size corresponding to the median value in the particle size distribution curve of the powder. For example, by measuring the particle size distribution with a commercially available laser diffraction scattering type particle size distribution meter (for example, Nikkiso Co., Ltd., model “MT3300”, etc.) Can be sought. The primary particle diameter means the number average value of the smallest unit particles constituting the powder, and can be known from, for example, an image obtained by a scanning electron microscope. Specifically, using a commercially available scanning electron microscope (for example, model “JSM-5300” manufactured by JEOL Ltd.), the powder was photographed at a magnification of 2,000 or 10,000 times, and within the field of view. It is easy to measure the size of an arbitrary 100 particles and take the average value. It can also be calculated from the specific surface area.
That is, the median diameter / primary particle diameter ratio means the number of primary particles that form secondary particles (aggregates). By making this ratio within the above range, the surface treatment is uniformly effective on the alkylphosphonic acid. Done.

Therefore, in order to perform the strong stirring as described above, a disperser, a homogenizer, an ultrasonic disperser, a wet ball mill, a wet vibration ball mill, a wet bead mill, a nanomizer, and a collision disperser (for example, a high pressure disperser) Etc. are preferably used.
The mixing and stirring time is set to such an extent that the carbon content in the obtained surface-treated aluminum nitride powder is in the above-described range.

After mixing and stirring the raw material AlN powder and the alkylphosphonic acid under the solvent as described above, the obtained slurry is heated to a temperature range of 80 ° C. to 300 ° C. depending on the type of the solvent used. Then, the target surface treatment is performed by drying, and an aluminum nitride powder with improved water resistance can be obtained.
Such drying is not limited to this, but is generally performed by an atmospheric pressure oven, a reduced pressure oven, a spray dryer, a medium fluidized dryer, a rocking mixer equipped with a drying mechanism, a pro-shear mixer, or the like.

  In addition, when the surface treatment is performed by the wet method as described above, when using a water-containing solvent, the raw material AlN powder may be gradually hydrolyzed, so that the treatment should be completed within 72 hours, particularly within 48 hours. Is desirable.

<Surface treated aluminum nitride powder>
Thus, the AlN powder of the present invention obtained by surface treatment using an alkylphosphonic acid as a treating agent (hereinafter sometimes referred to as water-resistant aluminum nitride powder) has a carbon content of 0.4 to 2.0 mass. %, Particularly in the range of 0.5 to 1.8% by mass, and has good water resistance.
For example, the water resistance time is 6 hours or more, and depending on the number of carbon atoms of the alkyl group of the alkylsulfonic acid used, it may be as long as 1 day or even 2 days or longer, and may be 5 days or longer.

  In addition, the water-resistant AlN powder has an elution amount of phosphorus suppressed to 5 ppm or less, and further, this elution amount is 4 ppm or less, particularly 3 ppm or less, more preferably 2 ppm, depending on the number of carbons of the alkyl group of the alkylsulfonic acid used. The following is also reduced, and metal corrosion due to phosphorus elution can be effectively prevented. For example, when it is blended with a resin and used as a heat dissipation composite material, it is possible to effectively avoid corrosion of a circuit that directly contacts the resin.

  Furthermore, the water-resistant AlN powder of the present invention effectively avoids a decrease in thermal conductivity due to the surface treatment in connection with the improvement in water resistance with a small amount of surface treatment. Thus, high thermal conductivity can be imparted.

<Heat dissipation composite material>
The water-resistant AlN powder of the present invention is suitably used as a heat-dissipating composite material by mixing with a resin by utilizing its high thermal conductivity.
The resin used for such purposes is not particularly limited, but the following thermoplastic resins are typical.
Polyethylene, polypropylene,
Ethylene-propylene copolymer, polymethylpentene,
Polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate,
Ethylene-vinyl acetate copolymer, polyvinyl alcohol,
Polyacetal, fluororesin (polyvinylidene fluoride,
Polytetrafluoroethylene, etc.),
Polyethylene terephthalate, polybutylene terephthalate,
Polyethylene 2,6 naphthalate, polystyrene,
Polyacrylonitrile, styrene-acrylonitrile copolymer,
ABS resin, polyphenylene ether (PPE) resin,
Modified PPE resin, aliphatic polyamides, aromatic polyamides,
Polyimide, polyamideimide,
Polymethacrylic acid (polymethacrylate such as polymethylmethacrylate),
Polyacrylic acid, polycarbonate,
Polyphenylene sulfide, polysulfone,
Polyethersulfone, polyethernitrile,
Polyetherketone, polyetheretherketone,
Polyketone, liquid crystal polymer, ionomer, etc.
Of course, in addition to thermoplastic resins, use thermosetting resins such as epoxies, acrylics, urethanes, silicones, phenols, imides, thermosetting modified PPEs, and thermosetting PPEs. You can also.

  When the water-resistant AlN powder of the present invention is used by mixing with the resin as described above, it is of course possible to use other fillers with relatively high thermal conductivity such as alumina, boron nitride, magnesium oxide, Since the water resistant AlN powder of the present invention has the highest thermal conductivity, in order to obtain a composite material having good heat dissipation, the content of the water resistant AlN powder in the composite material is 20% by mass or more, particularly 40%. It is preferable to set it as mass% or more. Further, from the viewpoint of the moldability of the composite material, the content of the water-resistant AlN powder is preferably 95% by mass or less, particularly preferably 90% by mass or less.

  The composite material as described above is suitably used as a heat radiating member for efficiently radiating heat generated from semiconductor components mounted on home appliances, automobiles, notebook personal computers, and the like. Used in the form of heat dissipation gel, heat dissipation sheet, phase change sheet, adhesive and the like. It can also be used as an insulating layer used for various substrates such as a metal base substrate, a printed circuit board, and a flexible substrate, a semiconductor sealant, an underfill, a housing, and a heat radiation fin.

  The thermal conductivity of the cured body of the composite material using the water-resistant AlN powder of the present invention is not particularly limited, but is preferably as high as possible in order to efficiently dissipate the heat generated from the semiconductor component, etc., and is 1.0 W / mK. The above is preferable.

EXAMPLES Hereinafter, although an Example and an application example demonstrate this invention concretely, this invention is not limited to these examples.
The test methods used in the following experiments are shown below.

Water resistance of AlN powder (water resistance time);
2 g of AlN powder and 100 g of ion-exchanged water are placed in a 120-ml polytetrafluoroethylene sealed container (PFA pressure-resistant jar: manufactured by Freon Industries Co., Ltd.) and allowed to stand at 120 ° C. After 6 hours, 12 hours, and 24 hours And the pH of water after that was measured with a pH test paper.
The time until the pH reached 10 or more was recorded as water resistant time, and was recorded as less than 6 hours, 6 hours or more and less than 12 hours, 12 hours or more and less than 24 hours, 1 day or more.

The viscosity of the composite material;
After mixing 2.0 g of AlN powder and 0.91 g of epoxy resin (ZX-1059: manufactured by Nippon Steel Chemical Co., Ltd.) in a mortar, using a rheometer (AR2000ex: manufactured by TA Instruments), the composite material at 25.5 ° C. The viscosity was measured.

Thermal conductivity of the composite material;
After mixing 2.00 g of AlN powder, 0.37 g of epoxy resin (JER807: manufactured by Mitsubishi Chemical) and 0.12 g of epoxy resin curing agent (JER Cure 113: manufactured by Mitsubishi Chemical) in a mortar, a hole having a diameter of 15 mm A 15 mm thick polytetrafluoroethylene mold was filled.
The polytetrafluoroethylene plate was sandwiched from both sides with a PET film and a 1 mm thick polytetrafluoroethylene plate, and heated at 80 ° C. and 20 MPa for 3 hours using a heat press (manufactured by ASONE).
The cured sample was taken out from the mold and polished using a rotary polishing machine so that the thickness of the sample was between 1.0 and 1.1 mm.
The thermal conductivity of this sample was measured with a thermal conductivity meter (PS-7: manufactured by Rigaku Corporation).

Carbon content of water resistant AlN powder;
A pre-surface treatment AlN powder and a surface treatment AlN powder (water-resistant AlN powder) were fired in an oxygen stream at 1350 ° C until no CO ₂ gas was generated, and carbon analysis was performed from the amount of CO ₂ gas generated. The carbon content was quantified using an apparatus (for example, EMIA-110: manufactured by Horiba, Ltd.), and the carbon content of the water-resistant AlN powder was calculated by the following formula.
Carbon content = (A−B) / C
A: Carbon amount after surface treatment B: Carbon amount before surface treatment C: Mass of AlN powder after surface treatment That is, this carbon amount indicates the ratio of the amount of carbon increased by surface treatment with alkylphosphonic acid. Corresponds to throughput.

Elution amount of phosphorus;
After putting 1 g of AlN powder and 50 g of water into a sealed container, it was allowed to stand at 120 ° C. for 24 hours. Solid-liquid separation is performed using a centrifuge (SN-1050: manufactured by AS ONE), and then solid components are further removed using a filter, and the obtained eluate is diluted as appropriate to obtain a 1% nitric acid solution. It was.
The nitric acid solution was subjected to luminescence analysis with an ICP emission analyzer (iCAP 6500: manufactured by Thermo Scientific), and the elution amount of phosphorus was quantified and displayed as the concentration (ppm) in the eluate.

In the following experiment, an AlN powder having the following physical properties was prepared.
AlN powder H:
BET specific surface area 2.6 m ² / g, Tokuyama grade H
AlN powder UM:
BET specific surface area 1.1m ² / g, Toyo Aluminum UM
AlN powder JD:
BET specific surface area 2.2m ² / g, JD made by Toyo Aluminum
Moreover, as alkyl phosphonic acid used for experiment, the thing made from a Wako Purechemical person was used, and as the ultrasonic cleaning machine, USD-2R made from ASONE was used.

<Example 1>
0.6 g of decylphosphonic acid and 30 g of isopropanol (IPA-SE manufactured by Tokuyama) were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder H was added to the above sample bottle, sealed, and shaken for 1 minute to mix. Next, the mixture was subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C., and then the slurry in the sample bottle was transferred to a petri dish and vacuum-dried at 200 ° C. for 3 hours in an oven. .
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 2>
0.75 g of dodecylphosphonic acid, 20 g of water and 15 g of ethanol (reagent special grade: manufactured by Wako Pure Chemical Industries, Ltd.) are put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. went.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken and mixed for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. And vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 3>
0.60 g of dodecylphosphonic acid, 21 g of water and 9 g of isopropanol (IPA-SE: manufactured by Tokuyama Co., Ltd.) are placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. It was.
Next, 30 g of AlN powder UM was added to the sample bottle, sealed, mixed by shaking for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 4>
0.45 g of dodecylphosphonic acid and 30 g of isopropanol (IPA-SE: manufactured by Tokuyama) were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder JD was added to the sample bottle, sealed, and shaken for 1 minute to mix. Ultrasonic irradiation was performed for 10 minutes with an ultrasonic cleaner heated to 40 ° C., followed by vacuum drying in the same manner as in Example 1.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 5>
Tetradecylphosphonic acid 0.54 g and water 30 g were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes using an ultrasonic cleaner heated to 50 ° C.
Next, 15 g of AlN powder H and 15 g of AlN powder UM were added to the sample bottle, sealed, mixed by shaking for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. In the same manner as in No. 1, vacuum drying was performed.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 6>
Put 0.30 g of hexadecylphosphonic acid, 24 g of water and 6 g of isopropanol (IPA-SE: manufactured by Tokuyama Co., Ltd.) in a sample bottle, seal and mix, and then apply ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 70 ° C. went.
Next, 15 g of AlN powder H and 15 g of AlN powder UM were added to the sample bottle, sealed, mixed by shaking for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. In the same manner as in No. 1, vacuum drying was performed.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 7>
Put 0.60 g of hexadecylphosphonic acid, 24 g of water and 16 g of methanol (special grade reagent: Wako Pure Chemical Industries, Ltd.) into a sample bottle, seal and mix, and then ultrasonically irradiate with an ultrasonic cleaner heated to 70 ° C. for 10 minutes. Went.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken and mixed for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 8>
0.75 g of hexadecylphosphonic acid and 40 g of water were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes using an ultrasonic cleaner heated to 70 ° C.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken for 1 minute, mixed, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 9>
Octadecylphosphonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 0.27 g and water 40 g were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 80 ° C.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken and mixed for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 10>
Put 0.36 g of octadecylphosphonic acid, 30 g of water and 10 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) into a sample bottle, tightly plug and mix, then apply ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 80 ° C. went.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken and mixed for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 11>
0.45 g of octadecylphosphonic acid, 30 g of water and 10 g of isopropanol (IPA-SE: manufactured by Tokuyama) were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 50 ° C. It was.
Next, 30 g of AlN powder JD was added to the sample bottle, sealed, mixed by shaking for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner (USD-2R: manufactured by ASONE) heated to 50 ° C. After that, it was vacuum dried in the same manner as in Example 1.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 12>
0.60 g of butylphosphonic acid and 30 g of water were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken for 1 minute, mixed, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 13>
0.30 g of octylphosphonic acid and 30 g of water were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken for 1 minute, mixed, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. Vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Example 14>
0.45 g of octylphosphonic acid and 30 g of water were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken and mixed for 1 minute, and further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C. And vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 1>
Table 1 shows the measured water resistance of the AlN powder H prepared for the surface treatment and the viscosity and thermal conductivity of the composite material prepared using the AlN powder H.

<Comparative example 2>
The physical properties and amounts of the AlN powder JD prepared for the surface treatment are shown in Table 1, and the measured water resistance and the viscosity and thermal conductivity of the composite material produced using the AlN powder JD are shown in Table 2.

<Comparative Example 3>
0.12 g of dodecylphosphonic acid and 30 g of water were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner heated to 40 ° C.
Next, 30 g of AlN powder H was added to the above sample bottle, sealed, mixed by shaking for 1 minute, and further subjected to ultrasonic irradiation with an ultrasonic cleaner heated to 40 ° C. for 10 minutes, as in Example 1. And vacuum dried.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 4>
1.50 g of dodecylphosphonic acid and 30 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes.
Next, 30 g of AlN powder H was added to the above sample bottle, sealed, mixed by shaking for 1 minute, further subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes, and then vacuum dried in the same manner as in Example 1. .
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 5>
0.09 g of octadecylphosphonic acid and 30 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes.
Next, 30 g of AlN powder H was added to the above sample bottle, sealed, mixed by shaking for 1 minute, further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner, and then dried in the same manner as in Example 1.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 6>
Octadecylphosphonic acid 1.20 g and ethanol (special reagent grade: Wako Pure Chemical Industries, Ltd.) 30 g were placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner.
Next, 30 g of aluminum nitride powder H was added to the above sample bottle, sealed, shaken and mixed for 1 minute, further subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner, and then vacuum dried as in Example 1. .
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 7>
As 2-ethylhexyl phosphoric acid, Phoslex A-8 manufactured by SC Organic Chemical Co., Ltd. was prepared.
0.60 g of the above-mentioned 2-ethylhexyl phosphoric acid and 30 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) were put in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes.
Next, after adding 30 g of aluminum nitride powder H to the above sample bottle and sealing it, shaking and mixing for 1 minute, and further performing ultrasonic irradiation for 10 minutes with an ultrasonic cleaner, the slurry in the sample bottle is transferred to a petri dish, It dried for 13 hours at 80 degreeC in oven.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 8>
ML-200 manufactured by Toho Chemical Co., Ltd. was prepared as dodecyl phosphate.
0.45 g of the above dodecyl phosphoric acid and 30 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken for 1 minute, mixed, and subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner, then the slurry in the sample bottle was transferred to a petri dish and oven Vacuum drying was performed at 200 ° C. for 3 hours.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

<Comparative Example 9>
As the octadecyl phosphate, Phoslex A-18 manufactured by SC Organic Chemical Co., Ltd. was prepared.
0.60 g of the above octadecyl phosphate and 30 g of ethanol (special reagent grade: manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a sample bottle, sealed and mixed, and then subjected to ultrasonic irradiation with an ultrasonic cleaner for 10 minutes.
Next, 30 g of AlN powder H was added to the sample bottle, sealed, shaken for 1 minute, mixed, and subjected to ultrasonic irradiation for 10 minutes with an ultrasonic cleaner, then the slurry in the sample bottle was transferred to a petri dish and oven Vacuum drying was performed at 200 ° C. for 3 hours.
Table 1 shows the types, physical properties, and amounts of the AlN powder and surface treatment agent used in the above surface treatment, and the water resistance of the obtained surface treated AlN powder, the elution amount of phosphorus, and the surface treated AlN powder. Table 2 shows the viscosity and thermal conductivity of the composite material prepared in this manner.

The meanings of the abbreviations used in Tables 1 and 2 are as follows.
Ex: Examples Com: Comparative example Dav: Average particle diameter BET: BET specific surface area

Claims (4)

  An aluminum nitride powder that is surface-treated with an alkylphosphonic acid having an alkyl group having 14 to 30 carbon atoms and contains carbon in an amount of 0.4 to 2.0% by mass.   2. The aluminum nitride powder according to claim 1, wherein when 1 g of the aluminum nitride powder is immersed in 50 g of ion exchange water and kept in a sealed container at 120 ° C. for 24 hours, the amount of phosphorus eluted is suppressed to 5 ppm or less.   The water resistance time indicated by the time for the pH to reach 10 is 5 days or more when 2 g of the aluminum nitride powder is immersed in 100 g of ion exchange water and kept at 120 ° C. in a sealed container. Aluminum nitride powder.   A heat-dissipating composite material comprising the aluminum nitride powder according to claim 1 and a resin.