JP5230361B2 - Manufacturing method of resin composition for molding - Google Patents

Description

  The present invention relates to a method for producing a molding resin composition containing aluminum nitride powder and a sintering aid by a melt-kneading method. More specifically, the aluminum nitride molding resin composition is capable of remarkably reducing structural defects in an aluminum nitride sintered body obtained by uniformly dispersing a sintering aid in an aluminum nitride powder and degreasing and firing the powder. Providing manufacturing methods.

  Aluminum nitride sintered bodies have high thermal conductivity and excellent electrical insulation, and are widely used as submounts for mounting semiconductor elements, various electronic circuit boards for power modules, packaging materials, and insulating materials. ing.

  In general, an aluminum nitride sintered body is obtained by molding a composition obtained by mixing aluminum nitride powder with a binder resin into a desired shape by various molding methods, degreasing as necessary, and then firing.

  As a method for producing the aluminum nitride molded body, a method is widely used in which aluminum nitride and a sintering aid are dispersed in a solvent in which a binder resin is dissolved, and this is molded into a predetermined shape such as a sheet (Patent Document 1). reference).

  On the other hand, a method has been proposed in which a thermoplastic resin and an aluminum nitride powder are melt-kneaded into a resin composition without using a solvent, and a thermoforming such as extrusion molding is performed with respect to the method of manufacturing the aluminum nitride molded body. (See Patent Document 2). The method of obtaining a molded body by melt-kneading with the above thermoplastic resin can increase the density of the molded body because the molded body does not contain a solvent, and the dimensional stability of the sintered body obtained by subsequent degreasing and firing is good. And it has the merit that productivity is also good because the drying process of a solvent is unnecessary.

  In Patent Document 1 for obtaining an aluminum nitride molding composition by melt-kneading with a thermoplastic resin, there is no example in which a sintering aid is used in the composition, but the aluminum nitride molded body is degreased, When obtaining an aluminum nitride sintered body by firing, generally a sintering aid is used in combination. That is, since aluminum nitride has strong covalent bonding and is difficult to sinter, it is common to use a sintering aid such as an oxide of a rare earth element or an oxide of an alkaline earth element. The sintering aid has a function of reacting with aluminum oxide formed on the surface of the aluminum nitride powder to generate a liquid phase, densifying the sintered body, and improving the thermal conductivity.

JP-A-5-124866 JP-A-5-43304

  However, an aluminum nitride molding resin composition containing a sintering aid, obtained by heating and kneading (melting and kneading) aluminum nitride powder, a sintering aid and a thermoplastic resin with a kneader such as a pressure kneader, When a sintered body is manufactured using a structural defect occurs in the manufactured sintered body, the sintered body density is not sufficiently increased, and thereby the mechanical strength improvement effect is insufficient, It has been found that there is a problem that variations occur. In particular, when a small sintering aid having an average particle size of 3 μm or less is used, the tendency appears remarkably.

  Accordingly, an object of the present invention is to provide an aluminum nitride sintered body produced by using an aluminum nitride molding composition obtained by melt-kneading aluminum nitride, a sintering aid and a thermoplastic resin. An object of the present invention is to provide a resin composition for molding aluminum nitride that has reduced structural defects and has a high effect of improving mechanical strength.

  The inventors of the present invention have intensively studied to achieve the above object in the process for producing an aluminum nitride molding resin composition by melt kneading. As a result, it was found that the sintering aid is relatively easy to aggregate when handled in a dry state. In particular, when the average particle size is 3 μm or less, the tendency is remarkable. And it became clear that this sintering auxiliary agent aggregates at the time of melt-kneading to a thermoplastic resin with aluminum nitride powder at the time of melt-kneading, and exists in the resin composition as unexpected large particles. For this reason, it is presumed that the auxiliary phase cannot be uniformly dispersed in the sintered body obtained by molding, degreasing and firing this resin composition, resulting in an increase in structural defects.

  As a result of further research based on the above knowledge, the present inventors have conducted sintering aid by carrying out melt-kneading with aluminum nitride and a thermoplastic resin in a state in which the cohesiveness of the sintering aid has been lowered. It has been found that a resin composition in which agglomeration of the agent can be prevented and the sintering aid is uniformly dispersed is obtained, and that the above object can be achieved.

  Further, as a method for reducing the cohesiveness of the sintering aid, it can be handled as a premixed sintering aid in which the sintering aid is dispersed and supported on at least a part of the aluminum nitride powder. As a result, the present invention has been found to be effective.

That is, the present invention provides an aluminum nitride powder, a sintering aid and a thermoplastic resin which are melt-kneaded to obtain a composition containing the thermoplastic resin, the aluminum nitride powder and the sintering aid. the sintering aid and a binder, after allowed wet dispersion in an organic solvent, a premix was prepared by removing the organic solvent, then, extrusion, characterized in that subjecting the premix to the melt-kneading It is a manufacturing method of the resin composition for shaping | molding.

  According to the present invention, since the particles of the sintering aid that are easily aggregated are in a state in which they are hardly aggregated by forming a preliminary mixture with the thermoplastic resin, the resin composition for molding aluminum nitride obtained by melt-kneading is obtained. It is possible to uniformly disperse the sintering aid therein, and a molded body in which the sintering aid is highly dispersed can be obtained by thermoforming such as extrusion molding using the same. By degreasing and firing, an aluminum nitride sintered body having few structural defects and excellent mechanical strength can be industrially produced at low cost and in large quantities.

[Aluminum nitride powder]
The aluminum nitride powder used for producing the aluminum nitride molding resin composition of the present invention (hereinafter also simply referred to as molding composition) is produced by a known method such as a direct nitriding method or an alumina reduction nitriding method, Alternatively, a mixture of these can be used without particular limitation. The aluminum nitride powder obtained by the reduction nitriding method is preferable in that the finally obtained aluminum nitride sintered body has good thermal conductivity. The impurities in the aluminum nitride powder are not particularly limited, but those having less impurities such as oxygen and cations are preferred. For example, the oxygen content is preferably 2.0% by weight or less, more preferably 0.8%. It is in the range of 4 wt% to 1.3 wt%, and the content of cationic impurities is preferably 0.3 wt% or less, more preferably 0.2 wt% or less. When such an aluminum nitride powder is used as a raw material, an aluminum nitride sintered body having excellent thermal conductivity can be obtained.

  The average particle size of the aluminum nitride powder is not particularly limited, but is usually 1.0 μm to 10.0 μm, preferably 1.0 μm to 5.0 μm, and most preferably 1.0 μm to 3.0 μm. When the average particle diameter of the aluminum nitride powder is within the above range, an aluminum nitride sintered body having high thermal conductivity and high mechanical strength can be obtained.

[Sintering aid]
A known sintering aid is used as the sintering aid used in the production of the molding resin composition of the present invention, and is generally selected from an alkaline earth metal or a rare earth element oxide. As the alkaline earth metal element, beryllium, magnesium, calcium, strontium, barium and the like are generally used, and calcium, strontium and barium are particularly preferably used. Further, as the rare earth element, yttrium, lanthanum, cerium, brasseosium, neodymium, promesium, samarium, europium, cadmium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, etc. are used, particularly yttrium, lanthanum, cerium, Neodymium is preferably used.

  The above-mentioned sintering aid is usually an oxide of the metal described above, and a metal compound that forms the metal oxide under the conditions in which the aluminum nitride powder is sintered, such as nitrate, carbonate, It can also be used as a chloride or the like.

  In addition, the rare earth metal compound and the alkaline earth metal compound may be used in combination, and several types may be used.

  The method of the present invention is more effective when the sintering aid contains yttrium oxide, which is particularly highly cohesive.

〔Thermoplastic resin〕
In the present invention, as the thermoplastic resin used for the production of the molding resin composition, a known one can be used without any limitation. Specific thermoplastic resins include hydrocarbon resins such as polyethylene, polypropylene, polymethylpentene, polybutene, polystyrene, styrene-butadiene resin, polymethyl methacrylate, polyethyl methacrylate, poly 2-ethylhexyl methacrylate, polybutyl methacrylate, Acrylic resins such as polyacrylate, ethylene-vinyl acetate copolymer, polar vinyl resins such as polyvinyl acetate, cellulose resins such as nitrocellulose, methylcellulose, hydroxymethylcellulose, polyacetal, polyamide, polycarbonate, polyphenylene ether, polyethylene terephthalate, Polybutylene terephthalate, styrene / butadiene, polyolefin, urethane, polyester, polyamide 1,2-polybutadiene, it includes such thermoplastic elastomers such as ionomers, but these may be used alone or in combination of two or more thereof.

  Among these thermoplastic resins, a thermoplastic resin selected from the group consisting of polymethyl methacrylate, polyethyl methacrylate, poly 2-ethylhexyl methacrylate, polybutyl methacrylate, and ethylene-vinyl acetate copolymer is superior to aluminum nitride powder. It is preferable in that it has chemical affinity and has good thermoformability such as extrusion and degreasing.

[Preliminary mixture of sintering aid and thermoplastic resin]
The greatest feature of the method for producing the molding resin composition of the present invention is that the aluminum nitride powder and the sintering aid are obtained before the molding resin composition is obtained by melt-kneading the aluminum nitride powder, the sintering aid and the thermoplastic resin. To prepare a premix with the agent.

  That is, by making at least a part of the aluminum nitride powder and the sintering aid a premix, the sintering aid is supported on the aluminum nitride powder and effectively re-aggregates when the entire composition is melt-kneaded. Can be prevented.

  In addition, the aluminum nitride powder used in preparation of the said premix can use a part or all of the aluminum nitride powder which comprises the resin composition for shaping | molding.

  In the present invention, the preparation of the premix is not particularly limited as long as the sintering aid can be dispersed in a state of being supported on the aluminum nitride powder at a predetermined particle size. A method in which the binder is wet-dispersed in an organic solvent and then the organic solvent is removed is preferable.

  As an organic solvent used in the preparation of the premix by the wet method, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, alcohols such as ethanol, propanol, and butanol, benzene, toluene, xylene, etc., from the ease of removal described later Aromatic hydrocarbons, halogenated hydrocarbons such as trichloroethylene, tetrachloroethylene, and bromochloromethane are preferred. These organic solvents can be used alone or in combination of two or more.

  The wet dispersion is not particularly limited as long as the sintering aid, the aluminum nitride powder and the organic solvent are mixed and the aluminum nitride powder and the sintering aid particles are dispersed in the organic solvent. A method of dispersing a mixture of a sintering aid and an organic solvent while crushing to a desired particle size by a wet crusher such as a ball mill is recommended. As another method, the sintering aid is crushed with a dry crusher to make a mixture with the aluminum nitride powder and the organic solvent, and then the aggregate of the sintering aid is crushed with the pulverizer or the stirring device. Can also be implemented.

  The material of the ball used in the ball mill is not particularly limited, and a ceramic or nylon material generally used for wet mixing of ceramics is used. From the viewpoint of efficiently pulverizing and dispersing the sintering aid, it is preferable to use ceramic balls, particularly alumina balls, and it is more preferable to use balls of different sizes in combination at any ratio. .

  After the sintering aid and the aluminum nitride powder are dispersed in an organic solvent, an operation of removing the organic solvent is performed. For this operation, a known dryer is used without any particular limitation, but a spray dryer in which the premix is obtained in the form of granules after removing the organic solvent is preferably used.

  The preliminary mixture obtained by the various methods described above should be one in which a sintering aid is carried on the aluminum nitride powder with an average particle size of 0.2 to 5 μm, particularly 0.5 to 3 μm. desirable. Further, it is desirable that the sintering aid in the premix has a maximum particle size of 20 μm or less, particularly 15 μm or less.

  In the preliminary mixture of the sintering aid and aluminum nitride powder of the present invention, the amount of the sintering aid is not particularly limited, but is 0.05 to 10 parts by weight with respect to 100 parts by weight of the aluminum nitride powder. The content is preferably 1 to 7 parts by weight, more preferably 3 to 6 parts by weight. When the content of the sintering aid is within the above range, the dispersion of the sintering aid is good.

  Moreover, in preparation of the said pre-mixture, in order to raise the supporting force of an aluminum nitride powder and a sintering auxiliary agent, a binder can be mix | blended as needed. Specific examples of binders preferably used include polyvinyl butyral, polymethyl methacrylate, polyethyl methacrylate, poly 2-ethylhexyl methacrylate, polybutyl methacrylate, cellulose acetate butyrate, nitrocellulose, polyvinyl alcohol, polyethylene oxide and polypropylene. Oxygen-containing organic polymers such as oxides, hydrocarbon-based synthetic resins such as petroleum resin, polyethylene, polypropylene, and polystyrene, and organic polymers such as polyvinyl chloride, wax, and emulsions thereof may be used. Two or more kinds can be mixed and used. The molecular weight when using the organic polymer as a binder is not particularly limited, but it is preferably 3,000 to 1,000,000, preferably 5,000 to 300,000.

  In the preparation of the premix, the binder is preferably one that dissolves in an organic solvent, and is used in an amount of 0 to 20 parts by weight with respect to 100 parts by weight of the aluminum nitride powder.

[Resin composition for extrusion molding]
In the present invention, the molding resin composition is obtained by melt-kneading the preliminary mixture of the sintering aid and the aluminum nitride powder, the thermoplastic resin and, if necessary, the aluminum nitride powder.

  In the melt kneading, the mixing ratio of the premix, the thermoplastic resin, and the aluminum nitride powder is not particularly limited, and any known composition can be adopted as the molding resin composition without any particular limitation.

  For example, in the obtained molding resin composition, the sintering aid is used in the range of 0.05 to 10 parts by weight, preferably 1 to 7 parts by weight with respect to 100 parts by weight of the aluminum nitride powder in terms of oxide. Within such a range, a suitable blending amount may be appropriately determined in consideration of the oxygen content, impurity content, particle diameter, and the like in the aluminum nitride powder.

  Further, the thermoplastic resin may be adjusted so as to have a ratio of 5 to 20 parts by weight, preferably 8 to 15 parts by weight, with respect to 100 parts by weight of the aluminum nitride powder. The physical properties of the bonded body are also favorable, which is preferable.

The molding resin composition of the present invention further contains, as other components, the aforementioned surfactants, plasticizers, lubricants, peptizers such as aliphatic amines, oils such as mineral oil and coconut oil, and the like. Also good.
As the surfactant, those described above can be used without particular limitation, and usually 0.01 parts by weight to 10 parts by weight, preferably 0.02 parts by weight to 3.0 parts by weight with respect to 100 parts by weight of the aluminum nitride powder. It can be used in amounts in the range of parts by weight. When the surfactant is used within the above range, the dispersion of the binder and the aluminum nitride becomes good. The sintering aid, organic binder, plasticizer, lubricant and the like can be incorporated in the aluminum nitride dispersion of the present invention in whole or in part.

The above-mentioned plasticizer can be used without any particular limitation, and is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the aluminum nitride powder.
The above-described lubricant can be used without particular limitation, and is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the aluminum nitride powder.

  In the molding resin composition obtained by the method of the present invention, the sintering aid preferably has an average particle diameter of 0.2 to 5 μm, and can be uniformly dispersed in a size of 0.5 to 3 μm. The maximum particle size can be 20 μm or less, in particular 15 μm or less.

Molded article obtained by using molding resin composition and the same above, the composition described above, 2.20~2.80g / cm ^3, in particular, a high density of 2.35~2.60g / cm ³ As a result, the strength of the molded body is increased, and the dimensional stability of the sintered body obtained by degreasing and firing is also improved.

When the molding resin composition of the present invention is used for extrusion molding, the viscosity at 120 ° C. and a shear rate of 100 (1 / S) is preferably in the range of 50 to 10000 Pa · s, preferably 100 to 6000 Pa · s. More preferably. When the viscosity is in the above range, the extrusion moldability is good and the strength of the extruded product is high. The viscosity of the molding resin composition of the present invention is, for example, the particle size, specific surface area, and filling of the aluminum nitride powder used. The amount can be increased or decreased by taking the amount into account and increasing or decreasing the type or molecular weight of the thermoplastic resin, the amount of plasticizer or lubricant.

[Method for adjusting molding resin composition]
In the present invention, the molding resin composition is obtained by melt-kneading the preliminary mixture of the sintering aid and aluminum nitride powder, a thermoplastic resin and, if necessary, the aluminum nitride powder with a known kneading apparatus. Examples of such a kneader include a pressure kneader, a Banbury mixer, a disk kneader, and a continuous kneader. For example, when kneading with a pressure kneader, the temperature can be 50 to 200 ° C., preferably 70 to 150 ° C., time 5 minutes to 3 hours, preferably 10 minutes to 2 hours.

  The supply to the kneading apparatus may be premixed, thermoplastic resin, aluminum nitride powder, and other components all at once, and may be pressure kneaded. The raw materials may be charged and further pressure kneaded.

  The form of the molding resin composition obtained by the method of the present invention is not particularly limited, but is preferably granulated (pelletized). For granulation, a known apparatus such as a feeder / ruder can be used.

[Method for producing molded body and sintered body using resin composition for molding]
In the present invention, as a method for producing a molded body using the molding resin composition, a known thermoforming method is employed without any particular limitation, but a rod-shaped, prismatic, pipe-shaped, or sheet-shaped molded body is reduced. Extrusion molding is suitable as a cost and mass production method.

  A known uniaxial or biaxial extruder and a known mold can be used for the extrusion. Moreover, although extrusion molding conditions differ according to the shape of an extrusion molding, and the capability of the extrusion machine to be used, generally extrusion pressure 0.5-100 MPa, Preferably 1-50 MPa, extrusion speed 1-300 mm / second, Preferably, it can be set to 5-200 mm / sec, cylinder temperature 50-300 degreeC, Preferably it can be set to 50-200 degreeC.

  The obtained molded body is degreased (deorganic component) and then fired to obtain an aluminum nitride sintered body.

  The degreasing can be performed by a known method such as a method by heating in a normal pressure atmosphere, a pressurized atmosphere, a reduced pressure atmosphere or the like, a method by extraction with a solvent or the like, and a method in which heating and extraction are combined.

  In addition, degreasing is preferably performed by heating in an atmosphere of atmospheric pressure, in air, in nitrogen, in hydrogen, etc., but in the air, the amount of residual carbon and residual oxygen can be easily adjusted. More preferably, degreasing is performed. The degreasing temperature is usually 200 to 900 ° C, preferably 300 to 600 ° C.

  Next, the degreased body obtained by the above degreasing is fired to obtain an aluminum nitride sintered body. As firing conditions, known conditions are employed without any particular limitation, but it is preferably performed in a neutral atmosphere such as argon or nitrogen.

  As the container for firing, a non-carbon made container such as an aluminum nitride sintered body or a boron nitride molded body may be used, and the molded body may be accommodated in the container and sintered.

  Firing of the degreased body is preferably carried out at a temperature of 1500 to 2000 ° C., preferably 1600 to 1900 ° C., for at least 1 hour, particularly 3 hours or more. The upper limit of the firing time is not particularly limited, but is usually about 6 hours.

〔Example〕
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measuring method of various physical properties is as follows.

<Particle size distribution of sintering aid and aluminum nitride powder>
The aluminum nitride powder was dispersed in a 5% sodium pyrophosphate aqueous solution using a homogenizer, and the average particle size (D ₅₀ ) was measured with a laser diffraction particle size distribution device (MICROTRAC HRA manufactured by Nikkiso Co., Ltd.).

<Cation impurity content of aluminum nitride powder>
The cation impurity content (metal element concentration) was determined by ICP emission analysis of the solution using “ICP-1000” manufactured by Shimadzu Corporation after the aluminum nitride powder was alkali-melted and then neutralized with acid.

<Oxygen content of aluminum nitride powder>
The oxygen content (oxygen concentration) was determined from the amount of CO gas generated by the high temperature pyrolysis method in a graphite crucible using “EMGA-2800” manufactured by Horiba.

<Average particle size and maximum particle size of sintering aid in premix and resin composition for molding>
(1) Photographs were taken of arbitrary 30 visual fields of a reflection electron image having a magnification of 5000 times and 20 μm × 20 μm with a scanning electron microscope (SEM) of the average particle size premix and the molding resin composition. Next, after all the yttrium oxide particles on the developed or printed photograph are traced, an equivalent circle diameter (D) is obtained using image analysis software IP-1000 (integrated application: A image kun) manufactured by Asahi Kasei Kogyo. ) And the average particle diameter Dn was calculated according to the following formula.
Dn = ΣnD / n
(2) Maximum particle size The preliminary mixture and the molding resin composition are observed with a scanning electron microscope (SEM) at an arbitrary 50 fields at a magnification of 1000 × 100 μm × 100 μm, and yttrium oxide particles are identified by a reflected electron image. The maximum particle size (Dmax) was defined as the particle size of the particle having the maximum particle size.
<Density of extruded product>
It was determined by the Archimedes method using a “high-precision hydrometer DH” manufactured by Toyo Seiki.

<Bending strength>
In accordance with JIS R1601, a three-point bending strength measurement was performed at a crosshead speed of 0.5 mm / min and a span of 30 mm. The width of the test piece was 4 mm and prepared by surface grinding. The bending strength was determined by measuring the average value of 5 samples.

<Thermal conductivity>
The measurement was performed by a laser flash method using a thermal constant measuring device PS-7 manufactured by Rigaku Corporation. The thickness correction was performed using a calibration curve.

  Moreover, the raw material in an Example is as follows.

Aluminum nitride powder (H grade manufactured by Tokuyama Corporation, average particle diameter (D ₅₀ ): 1.25 μm, oxygen content: 0.8 wt%, cationic impurity content Ca: 220 ppm, Si: 45 ppm, Fe: 15 ppm )
・ Sintering aid ・ Yttrium oxide (High purity yttrium oxide made in Japan yttrium (purity 99.9% or more))
Average particle diameter (D ₅₀ ): 1.5 μm, specific surface area: 12.5 m ² / g)
・ Binder A1: Polybutylmethacrylate (PBMA)
Product name: Koreisha Chemical Co., Ltd. Oricox KC-500 (nonvolatile content: 45%)
-Thermoplastic resin A2: Ethylene-vinyl acetate copolymer (EVA)
Product name: EV220 manufactured by Mitsui DuPont Polychemical Co., Ltd.
A3: Polybutylmethacrylate (PBMA)
Product name: M6003 manufactured by Negami Kogyo Co., Ltd.
・ Plasticizer Bis (2-ethylhexyl) phthalate (DOP)
・ Lubricant: Stearic acid polyethylene glycol (average molecular weight 20,000)
・ Surfactant Carboxylated trioxyethylene tridecyl ether Product name: NIKKOL ECT-7 manufactured by Nikko Chemicals Co., Ltd.
・ Organic solvent Toluene solvent (Purity 99.7% or more)
Ethanol solvent (purity 99.5% or more)
Example 1
An apparently 40% alumina ball having a Vickers hardness of 1200 and a diameter of 20 mm is put in a nylon pot having an internal volume of 10 L, and then 100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, hexaglycerin monooleate 1 Parts by weight, polybutyl methacrylate (A1) 5 parts by weight, carboxylated trioxyethylene tridecyl ether 0.5 parts by weight, polyethylene glycol 0.5 parts by weight, toluene-ethanol mixed solvent 130 parts by weight (toluene: ethanol = 90: 10) was added and ball mill mixing was performed for 16 hours to obtain a white slurry. The slurry thus obtained was spray-dried by a spray dryer method to obtain a premix (A) of a sintering aid and aluminum nitride powder. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (A).

  Next, 110 parts by weight of the obtained preliminary mixture (A), 8 parts by weight of ethylene-vinyl acetate copolymer (A2), 1 part by weight of stearic acid, and 5 parts by weight of bis (2-ethylhexyl) phthalate were added to a Banbury mixer ( Using a Toyo Seiki Laboplast Mill Model 100C Mixer Type B-250), the mixture was kneaded at 100 ° C. for 20 minutes. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped resin composition for extrusion molding (A).

  The obtained resin composition for extrusion molding (A) was molded using a vacuum extruder (FM-20, manufactured by Miyazaki Tekko Co., Ltd.), a cylinder temperature of 80 ° C., and a sheet-like extrusion molding having a thickness of 1 mm × width of 60 mm. A body (A) was obtained. The extrusion pressure was 2.5 MPa and the extrusion speed was 1.1 mm / sec.

  The obtained extruded product (A) was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, sintered at 1730 ° C. in a nitrogen atmosphere for 6 hours, and sintered. A body (A) was obtained. The bending strength of the obtained sintered body was measured.

  Final blending ratio and viscosity of resin composition for extrusion molding (A), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in resin composition for extrusion molding (A), extrusion molded body ( Table 2 shows the measurement results of the density of A), the bending strength of the sintered body (A), and the thermal conductivity.

Example 2
In Example 1, a premix (B) of a sintering aid and aluminum nitride powder was obtained in the same manner as in Example 1 except that the blending amount of yttrium oxide was 7 parts by weight. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (B).

  Next, in the same manner as in Example 1, an extrusion molding resin composition (B), an extrusion molding (B), and a sintered body (B) were obtained. The extrusion pressure was 2.7 MPa, and the extrusion speed was 1.0 mm / sec. Final blending ratio and viscosity of the resin composition for extrusion molding (B), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in the resin composition for extrusion molding (B), Table 2 shows the measurement results of the density of B), the bending strength of the sintered body (B), and the thermal conductivity.

Example 3
In Example 1, a premix (C) of a sintering aid and aluminum nitride powder was obtained in the same manner as in Example 1 except that the blending amount of yttrium oxide was 3 parts by weight. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (C).

  Next, in the same manner as in Example 1, a resin composition for extrusion molding (C), an extrusion molded body (C), and a sintered body (C) were obtained. The extrusion pressure was 2.4 MPa, and the extrusion speed was 1.1 mm / sec. Final blending ratio and viscosity of resin composition for extrusion molding (C), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in resin composition for extrusion molding (C), extrusion molded body ( Table 2 shows the measurement results of the density of C), the bending strength of the sintered body (C), and the thermal conductivity.

Comparative Example 1
An apparently 40% alumina ball having a Vickers hardness of 1200 and a diameter of 20 mm is put in a nylon pot having an internal volume of 10 L, and then 100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, hexaglycerin monooleate 1 1 part by weight, 0.5 part by weight of carboxylated trioxyethylene tridecyl ether, 0.5 part by weight of polyethylene glycol, 130 parts by weight of toluene-ethanol mixed solvent (toluene: ethanol = 90: 10) are charged and mixed for 16 hours by ball mill The white slurry was obtained. The slurry thus obtained was spray-dried by a spray dryer method to obtain a premix (D) of a sintering aid and aluminum nitride powder. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (D).

  Next, 105 parts by weight of the obtained premix (D), 8 parts by weight of ethylene-vinyl acetate copolymer (A2), 4 parts by weight of polybutyl methacrylate (A3), 1 part by weight of stearic acid, bis (2 phthalate) 5 parts by weight of ethylhexyl was kneaded at 100 ° C. for 20 minutes using a Banbury mixer (Toyo Seiki Laboplast Mill Model 100C Mixer Type B-250). Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped resin composition for extrusion molding (D).

  The obtained resin composition for extrusion molding was molded using a vacuum extruder (FM-20, manufactured by Miyazaki Tekko Co., Ltd.), a cylinder temperature of 80 ° C., and a sheet-like extrusion molded body (A ) The extrusion pressure was 4.3 MPa and the extrusion speed was 0.9 mm / sec.

  The obtained extruded product (D) was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, sintered at 1730 ° C. in a nitrogen atmosphere for 6 hours, and sintered. A body (D) was obtained. The bending strength of the obtained sintered body was measured.

  Final blending ratio and viscosity of the resin composition for extrusion molding (D), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in the resin composition for extrusion molding (D), Table 2 shows the measurement results of the density of D), the bending strength of the sintered body (D), and the thermal conductivity.

Example 4
In Example 1, a premix (E) of a thermoplastic resin and a sintering aid was obtained in the same manner as in Example 1 except that a nylon ball containing an iron core was used instead of the alumina ball. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (E).

  Next, in the same manner as in Example 1, an extrusion molding resin composition (E), an extrusion molding (E), and a sintered body (E) were obtained. The extrusion pressure was 2.8 MPa and the extrusion speed was 1.0 mm / sec. Final blending ratio and viscosity of the resin composition for extrusion molding (E), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in the resin composition for extrusion molding (E), extrusion molded body ( Table 2 shows the measurement results of the density of E), the bending strength of the sintered body (E), and the thermal conductivity.

Comparative Example 2
In Example 4, a premix (F) of a thermoplastic resin and a sintering aid was obtained in the same manner as in Example 4 except that an iron ball-containing nylon ball was used instead of the alumina ball. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary mixture (F).

  Next, a resin composition for extrusion molding (F), an extrusion molded body (F), and a sintered body (F) were obtained in the same manner as in Example 1. The extrusion pressure was 4.7 MPa and the extrusion speed was 0.9 mm / sec. Final blending ratio and viscosity of resin composition for extrusion molding (F), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in resin composition for extrusion molding (F), extrusion molded body ( Table 2 shows the measurement results of the density of F), the bending strength of the sintered body (F), and the thermal conductivity.

Comparative Example 3
100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, 12 parts by weight of ethylene-vinyl acetate copolymer (A2), 1 part by weight of stearic acid, 5 parts by weight of bis (2-ethylhexyl) phthalate were added to a Banbury mixer (Toyo Seiki) Manufactured by Labo Plast Mill Model 100C Mixer Type B-250) and kneaded at 100 ° C. for 30 minutes. The total charge of these raw materials was adjusted to 70% with respect to the mixer kneading capacity. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped resin composition for extrusion molding (G).

Next, an extruded body (G) was obtained in the same manner as in Example 1. The extrusion pressure was 3.0 MPa and the extrusion speed was 1.0 mm / sec. The obtained extruded product (G) was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, sintered at 1730 ° C. in a nitrogen atmosphere for 6 hours, and sintered. A body (G) was obtained. Final blending ratio and viscosity of the resin composition for extrusion molding (G), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in the resin composition for extrusion molding (F), extrusion molded body ( Table 3 shows the measurement results of the density of G), the bending strength of the sintered body (G), and the thermal conductivity .
Comparative Example 4
100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, 8 parts by weight of ethylene-vinyl acetate copolymer (A2), 4 parts by weight of polybutyl methacrylate (A3), 1 part by weight of stearic acid, bis (2-ethylhexyl phthalate) ) 5 parts by weight was kneaded at 100 ° C. for 30 minutes using a Banbury mixer (Toyo Seiki Laboplast Mill Model 100C Mixer Type B-250). The total charge of these raw materials was adjusted to 70% with respect to the mixer kneading capacity. Next, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped resin composition for extrusion molding (H).

  Next, in the same manner as in Example 1, an extruded product (H) was obtained. The extrusion pressure was 4.9 MPa, and the extrusion speed was 0.9 mm / sec. The obtained extruded product (H) was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, sintered at 1730 ° C. in a nitrogen atmosphere for 6 hours, and sintered. Body (H) was obtained. Final blending ratio and viscosity of the resin composition for extrusion molding (H), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in the resin composition for extrusion molding (F), extrusion molding ( Table 3 shows the measurement results of the density of H), the bending strength of the sintered body (H), and the thermal conductivity.

Comparative Example 5
Extrusion molding resin composition in the same manner as in Comparative Example 2 except that the kneading time in the Banbury mixer (Laboplast Mill model 100C mixer type B-250 manufactured by Toyo Seiki Co., Ltd.) was changed from 30 minutes to 2 hours. (I), an extruded product (I) was obtained.

  Next, in the same manner as in Example 1, an extruded product (I) was obtained. The extrusion pressure was 4.7 MPa and the extrusion speed was 0.9 mm / sec. The obtained extruded product (I) was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, sintered at 1730 ° C. in a nitrogen atmosphere for 6 hours, and sintered. Body (I) was obtained. Final blending ratio and viscosity of resin composition for extrusion molding (B), average particle diameter (Dn) and maximum particle diameter (Dmax) of yttrium oxide in resin composition for extrusion molding (F), extrusion molded body ( Table 3 shows the measurement results of the density of I), the bending strength of the sintered body (I), and the thermal conductivity.

  By using the molding resin composition of the present invention and extruding into a rod shape, prismatic shape, pipe shape, or sheet shape, an aluminum nitride sintered body can be obtained with high productivity. Furthermore, since it is possible to obtain an aluminum nitride sintered body with few structural defects in which the sintering aid is uniformly dispersed, it is possible to obtain submounts for mounting semiconductor elements, various electronic circuit boards for power modules, or packages. Applicable to materials.

Claims (4)

When the aluminum nitride powder, the sintering aid and the thermoplastic resin are melt-kneaded to obtain a composition containing the thermoplastic resin, the aluminum nitride powder and the sintering aid, the aluminum nitride powder, the sintering aid and binders after allowed wet dispersion in an organic solvent, a premix prepared by removing organic solvent, then extruded resin composition, characterized by subjecting said premix to said melt kneading Manufacturing method.   The process according to claim 1, wherein the organic solvent is removed by spray drying.   The manufacturing method of Claim 2 which performs the said wet dispersion using a ball mill. The resin composition for extrusion molding contains 5 to 20 parts by weight of a thermoplastic resin and 0.05 to 10 parts by weight of a sintering aid with respect to 100 parts by weight of the aluminum nitride powder. The manufacturing method as described in any one of -3 .