JP2010105893A - Method for producing molding resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a molding resin composition from which an aluminum nitride sintered compact with few structural defects in which a sintering aid is uniformly dispersed in aluminum nitride powder can be obtained, and which is excellent in productivity. <P>SOLUTION: The method for producing a molding resin composition includes preparing a preliminary dispersion of a sintering aid and a thermoplastic resin containing the sintering aid in a state with an average particle diameter of 0.1-5 μm and a maximum particle diameter of ≤20 μm, and melting and kneading the preliminary dispersion with the thermoplastic resin and aluminum nitride powder to obtain a composition comprising the thermoplastic resin, aluminum nitride powder and sintering aid. <P>COPYRIGHT: (C)2010,JPO&INPIT

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. A method for manufacturing a product is provided.

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 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 is widely implemented (Patent Literature). 1).

  On the other hand, a method is proposed in which a thermoplastic resin and aluminum nitride powder are melt-kneaded into a resin composition without using a solvent, and a thermoforming such as extrusion molding is performed for the above-described aluminum nitride molded body manufacturing method. (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 has good dimensional stability in subsequent degreasing and firing, and further drying of the solvent. Since there is no need for a process, it has an advantage of good productivity.

  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 the above, structural defects are generated in the manufactured sintered body, and the sintered body density is not sufficiently increased. It has been found that there is a problem that occurs. 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 which has a reduced structure defect and a high effect of improving strength.

  The inventors of the present invention have intensively studied to achieve the above object in the method for producing a resin composition for molding aluminum nitride 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. Therefore, it is presumed that the auxiliary phase cannot be uniformly formed in the sintered body obtained by molding, degreasing and firing the resin composition, and the structural defects increase.

  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, at least a part of the thermoplastic resin and the sintering aid are wetted in the presence of an organic solvent capable of dissolving the thermoplastic resin. The present inventors have found that it is effective to disperse the mixture by means such as pulverization and remove the organic solvent as a preliminary dispersion of the sintering aid, thereby completing the present invention.

  That is, in the present invention, when the composition containing the thermoplastic resin, the aluminum nitride powder and the sintering aid is obtained by melt-kneading the aluminum nitride powder, the sintering aid and the thermoplastic resin, the thermoplastic resin is used. A method for producing an aluminum nitride molding resin composition, comprising preparing a preliminary dispersion of at least a part of a sintering aid and then subjecting the preliminary dispersion to the melt-kneading.

  According to the present invention, since the particles of the sintering aid that are easily aggregated are hardly aggregated by forming a preliminary dispersion 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 in the product, 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, it is possible to industrially produce an aluminum nitride sintered body having few structural defects and excellent mechanical strength at low cost and in large quantities.

[Aluminum nitride powder]
The aluminum nitride powder used in the production of the aluminum nitride molding resin composition of the present invention (hereinafter also simply referred to as a molding composition) is produced by a known method such as a direct nitriding method or an alumina reduction method, or These mixtures 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. It is 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, and 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 dispersion of sintering aid and thermoplastic resin]
The greatest feature of the method for producing a molding resin composition of the present invention is that at least one of the thermoplastic resins described above is obtained before melt molding the aluminum nitride powder, the sintering aid and the thermoplastic resin to obtain the molding resin composition. The purpose is to prepare a predispersion of a part and the sintering aid.

  That is, by using at least a part of the thermoplastic resin and the sintering aid as a pre-dispersion, the sintering aid is coated with the thermoplastic resin, which effectively re-aggregates when the entire composition is melt-kneaded. Can be prevented.

  In addition, if the thermoplastic resin used in preparation of the said pre-dispersion is one type of thermoplastic resin which comprises the resin composition for shaping | molding, the part or all can be used. Further, when a mixture of a plurality of types of thermoplastic resins is used, some types of resins selected from those thermoplastic resins may be used, or a part of a mixture of thermoplastic resins or All may be used.

  In the present invention, the preparation of the preliminary dispersion is not particularly limited as long as the sintering aid can be dispersed in a state of being coated with a thermoplastic resin at a predetermined particle size.

  For example, at least a part of the thermoplastic resin and a sintering aid are wet-dispersed in the presence of an organic solvent capable of dissolving the thermoplastic resin, and then adjusted by removing the organic solvent (wet Method), a sintering aid and a thermoplastic resin are mixed with a known kneading apparatus with a kneading torque set high (dry method). However, in order to achieve a high degree of dispersibility of the sintering aid, a wet method is recommended.

(Wet method)
In the present invention, the wet method for preparing the pre-dispersion is a method in which at least a part of the thermoplastic resin and the sintering aid are wet-dispersed in the presence of an organic solvent capable of dissolving the thermoplastic resin. , A method of adjusting by removing the organic solvent.

  The organic solvent used in the preparation of the preliminary dispersion by the wet method can be appropriately selected as long as it can dissolve the thermoplastic resin. For example, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as ethanol, propanol and butanol, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as trichloroethylene, tetrachloroethylene and bromochloromethane And the like 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 it is a method of mixing the sintering aid, the thermoplastic resin and the organic solvent, and dispersing the particles of the sintering aid in the organic solvent in which the thermoplastic resin is dissolved. A method of dispersing a mixture of a binder, a thermoplastic resin, and an organic solvent while crushing to a desired particle size with 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 a thermoplastic resin and an 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. .

  In the wet method, after obtaining a dispersion of the sintering aid and the thermoplastic resin 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 a preliminary dispersion is obtained in the form of granules after removing the organic solvent is preferably used.

(Dry method)
In the present invention, the dry method for preparing the preliminary dispersion is preferably a method in which the sintering aid and the thermoplastic resin are mixed with a known kneading apparatus while setting the kneading torque to be high.

  Examples of the kneading apparatus used in the dry method include known kneading apparatuses such as a pressure kneader, a Banbury mixer, a disk kneader, a uniaxial or biaxial continuous kneader. Among them, when kneading with a pressure kneader, it can be carried out under conditions of a temperature of 50 to 250 ° C., preferably 70 to 200 ° C., a time of 5 minutes to 10 hours, and preferably 10 minutes to 5 hours. The sintering aid and the thermoplastic resin may be charged all at once and may be pressure-kneaded. Alternatively, a part of the sintering aid and the thermoplastic resin may be pressure-kneaded and then the remaining raw materials may be charged and further pressure-kneaded. In order to disperse the sintering aid efficiently, the filling amount of the sintering aid, the thermoplastic resin molecular weight, the kneading conditions are set so that the kneading torque is preferably 5 N · m or more, more preferably 10 N · m or more. Etc. are preferably set.

  When the aluminum nitride powder, the sintering aid and the thermoplastic resin are melted and kneaded at once as in the conventional method, the kneading torque is small, usually 3 N · m or less.

  The preliminary dispersion obtained by the various methods described above is obtained by dispersing the sintering aid in the thermoplastic resin with an average particle size of 0.2 to 5 μm, particularly 0.5 to 3 μm. It is desirable. The sintering aid in the preliminary dispersion preferably has a maximum particle size of 20 μm or less, particularly 15 μm or less.

  In the preliminary dispersion of the sintering aid and thermoplastic resin of the present invention, the amount of the sintering aid is not particularly limited, but is preferably 50 to 800 parts by weight, preferably 100 parts by weight of the thermoplastic resin. Contains 60 to 700 parts by weight, more preferably 100 to 600 parts by weight. When the content of the sintering aid is within the above range, the dispersion of the sintering aid is good.

  Moreover, surfactant, a plasticizer, and a lubricant can be mix | blended with the said preliminary dispersion as needed.

  Specific examples of the surfactant suitably used in the present invention include carboxylated trioxyethylene tridecyl ether, diglycerin monooleate, diglycerin monostearate, carboxylated heptaoxyethylene tridecyl ether, tetraglycerin mono Examples include oleate, hexaglycerin monooleate, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan monooleate.

  The plasticizer is not particularly limited, and specifically, polyethylene glycol and derivatives thereof, dimethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, dioctyl phthalate, butyl stearate, tricresol phosphate, tri-N-butyl phosphate. Fate, glycerin and the like can be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  The lubricant is not particularly limited, and specifically, petroleum waxes such as paraffin, synthetic waxes such as polyethylene wax, fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; Those esters are mentioned.

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

  In the melt kneading, the mixing ratio of the preliminary dispersion, 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 6 parts by weight, based on 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 are 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.

  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 during degreasing and sintering 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 increased or decreased by considering the particle size, specific surface area, and filling amount of the aluminum nitride powder used, for example, the type and molecular weight of the thermoplastic resin, the amount of plasticizer and lubricant. Can be increased or decreased.

[Method for adjusting molding resin composition]
In the present invention, the molding resin composition is obtained by melting and kneading the preliminary dispersion of the sintering aid and the thermoplastic resin, the thermoplastic resin and 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 carried out by adding the pre-dispersion, thermoplastic resin, aluminum nitride powder, and other components all at once, and pressure kneading. May be charged and further kneaded under pressure.

  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 particular limitation, but extrusion molding is preferred.

  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.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Particle size distribution of sintering aid and aluminum nitride powder>
The aluminum nitride powder was dispersed in sodium pyrophosphate using a homogenizer, and the average particle size (D ₅₀ ) was measured using 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 an 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 diameter and maximum particle diameter of sintering aid in pre-dispersion and molding resin composition>
(1) The average particle size preliminary dispersion was selected by scanning electron microscope (SEM), arbitrarily selecting 10 fields of view of the reflected electron image at a magnification of 5000 times and 20 μm × 20 μm, and the particle size was measured for all particle systems. The number average particle diameter Dn was calculated according to

Dn = ΣnD / n
(2) Maximum particle diameter The preliminary dispersion was observed with a scanning electron microscope (SEM) at an arbitrary 50 visual field of a reflected electron image at a magnification of 1000 times and 100 μm × 100 μm, and the largest particle diameter (Dmax ).

<Viscosity of molding resin composition>
Using a Capillograph 1B manufactured by Toyo Seiki Seisakusho (using a capillary with a length of 20 mm and a diameter of 1 mm), the viscosity was measured at a measurement temperature of 120 ° C. and an extrusion speed of 5 to 200 mm / min. From the graph, the viscosity at a shear rate of 100 (1 / second) was determined.

<Density of extruded product>
It was determined by the Archimedes method using a “high-precision hydrometer DH” manufactured by Toyo Seiki.

<Bending strength>
According to JIS R1601, 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>
It measured by the laser flash method using the Rigaku Denki Co., Ltd. thermal constant measuring apparatus PS-7. Thickness correction was performed using a calibration curve.

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

-Thermoplastic resin A1: Ethylene-vinyl acetate copolymer (EVA)
Product name: EV220 manufactured by Mitsui DuPont Polychemical Co., Ltd.
A2: Polybutylmethacrylate (PBMA)
Product name: M6003 manufactured by Negami Kogyo Co., Ltd.
Sintering aid Yttrium oxide (high purity yttrium oxide (purity 99.9% or more) manufactured by Japan Yttrium, average particle size (D ₅₀ ): 1.5 μm, specific surface area: 12.5 m ² / g)
Aluminum nitride powder Aluminum nitride powder (H grade manufactured by Tokuyama Corporation, average particle size (D ₅₀ ): 1.25 μm, oxygen content: 0.8 wt%, cationic impurity content Ca: 220 ppm, Si: 45 ppm, Fe: 15 ppm)
・ Plasticizer Bis (2-ethylhexyl) phthalate (DOP)
Lubricant Stearic acid Example 1
100 parts by weight of ethylene-vinyl acetate copolymer, 125 parts by weight of yttrium oxide, and 5 parts by weight of stearic acid are kneaded at 100 ° C. for 30 minutes using a Banbury mixer (Toyo Seiki Laboplast Mill Model 100C Mixer Type B-250). did. The total charge amount of these raw materials was adjusted to 70% by volume with respect to the mixer kneading capacity. The torque during kneading was 10 N · m. Subsequently, the obtained kneaded material was granulated at 100 ° C. in a single-screw extruder to obtain a preliminary dispersion (A) of a thermoplastic resin and a sintering aid. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (A).

  Next, 100 parts by weight of the aluminum nitride powder, 9.2 parts by weight of the obtained preliminary dispersion (A), 8 parts by weight of ethylene-vinyl acetate copolymer, 0.8 parts by weight of stearic acid, bis (2-phthalate 4 parts by weight of ethylhexyl) was put into the Banbury mixer and kneaded at 100 ° C. for 20 minutes. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped molding resin composition. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  The obtained molding resin composition was molded using a vacuum extruder (FM-20, manufactured by Miyazaki Tekko Co., Ltd.) to obtain a sheet-like extruded product having a thickness of 1 mm and a width of 60 mm. The cylinder temperature was 80 ° C., the extrusion pressure was 2 MPa, and the extrusion speed was 16 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. The bending strength of the obtained sintered body was measured.

  Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Example 2
In Example 1, a preliminary dispersion (B) of a thermoplastic resin and a sintering aid was obtained in the same manner as in Example 1 except that polybutyl methacrylate was used instead of the ethylene-vinyl acetate copolymer. . The torque during kneading was 15 N · m. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (B).

Next, in the same manner as in Example 1, a molding resin composition and an extruded product were obtained. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding. The extrusion pressure was 5 MPa and the extrusion speed was 14 mm / sec.
The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Example 3
100 parts by weight of polybutylmethacrylate, 500 parts by weight of yttrium oxide, and 10 parts by weight of stearic acid were kneaded at 100 ° C. for 30 minutes using a Banbury mixer (Toyo Seiki Lab Plast Mill Model 100C Mixer Type B-250). The torque during kneading was 13 N · m. The total charge amount of these raw materials was adjusted to 70% by volume with respect to the mixer kneading capacity. Subsequently, the obtained kneaded material was granulated at 100 ° C. in a single screw extruder to obtain a preliminary dispersion (C) of a thermoplastic resin and a sintering aid. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (C).

  Next, 100 parts by weight of aluminum nitride powder, 6.3 parts by weight of the obtained pre-dispersion (C), 8 parts by weight of ethylene-vinyl acetate copolymer, 3 parts by weight of polybutyl methacrylate, 0.7 parts by weight of stearic acid Then, 4 parts by weight of bis (2-ethylhexyl) phthalate was charged into the Banbury mixer and kneaded at 100 ° C. for 20 minutes. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped molding resin composition. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  Next, an extruded product was obtained in the same manner as in Example 1. The extrusion pressure was 4.5 MPa and the extrusion speed was 14 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Example 4
An apparently filling ratio of 40% nylon balls with a core diameter of 25 mm was placed in a 10 L nylon pot. Next, 100 parts by weight of polybutyl methacrylate, 500 parts by weight of yttrium oxide powder, 100 parts by weight of toluene, and 20 parts by weight of ethanol were added, and ball mill mixing was performed for 16 hours to obtain a sintering aid solution (dispersion). .

  The obtained sintering aid solution was dried with a spray dryer to obtain a preliminary dispersion (D) of thermoplastic resin and sintering aid. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (D).

  Next, 100 parts by weight of aluminum nitride powder, 6 parts by weight of the resulting predispersion (D), 8 parts by weight of ethylene-vinyl acetate copolymer, 3 parts by weight of polybutyl methacrylate, 1 part by weight of stearic acid, bisphthalate 4 parts by weight of (2-ethylhexyl) was put into the Banbury mixer and kneaded at 100 ° C. for 20 minutes. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped molding resin composition. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  The obtained molding resin composition was molded using a vacuum extruder (FM-20, manufactured by Miyazaki Tekko Co., Ltd.) to obtain a sheet-like extruded product having a thickness of 1 mm and a width of 60 mm. The cylinder temperature was 80 ° C., the extrusion pressure was 4.5 MPa, and the extrusion speed was 14 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Example 5
In Example 3, a pre-dispersion of a thermoplastic resin and a sintering aid (in the same manner as in Example 3 except that alumina balls having a Vickers hardness of 1200 and a ball diameter of 10 mm were used instead of nylon balls) E) was obtained. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (E).

  Next, in the same manner as in Example 3, a molding resin composition and an extruded product were obtained. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding. The extrusion pressure was 4 MPa and the extrusion speed was 15 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Example 6
An apparently filling rate of 40% alumina balls having a Vickers hardness of 1200 and a ball diameter of 10 mm was placed in a 10 L nylon pot. Next, 100 parts by weight of polybutyl methacrylate, 250 parts by weight of yttrium oxide powder, 100 parts by weight of aluminum nitride powder, 400 parts by weight of toluene, and 200 parts by weight of ethanol were added, and ball mill mixing was performed for 16 hours to obtain a sintering aid solution. (Dispersion) was obtained.

  The obtained sintering aid solution was dried with a spray dryer to obtain a preliminary dispersion (F) of a thermoplastic resin and a sintering aid. Table 1 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained preliminary dispersion (F).

  Next, aluminum nitride powder parts by weight, the obtained preliminary dispersion (F) 12 parts by weight, ethylene-vinyl acetate copolymer 8 parts by weight, polybutyl methacrylate 2 parts by weight, stearic acid 1 part by weight, bisphthalate ( 4 parts of 2-ethylhexyl) was put into the Banbury mixer and kneaded at 100 ° C. for 20 minutes. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped molding resin composition. Table 2 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  Next, an extruded product was obtained in the same manner as in Example 3. The extrusion pressure was 4 MPa and the extrusion speed was 15 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 2 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Comparative Example 1
100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, 12 parts by weight of ethylene-vinyl acetate copolymer, 1 part of stearic acid, and 4 parts of bis (2-ethylhexyl) phthalate are banbury mixers (Laboplast Mill, manufactured by Toyo Seiki) The mixture was kneaded at 100 ° C. for 30 minutes using a 100C mixer type B-250). 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 molding resin composition. Table 3 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

The maximum particle diameter of yttrium oxide is 50 μm, and many yttrium oxide aggregates exceeding 20 μm were observed.
Next, an extruded product was obtained in the same manner as in Example 1. The extrusion pressure was 5 MPa and the extrusion speed was 13 mm / sec.

The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. The final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity are shown in Table 3. Comparative Example 2
Banbury mixer (100 parts by weight of aluminum nitride powder, 5 parts by weight of yttrium oxide, 8 parts by weight of ethylene-vinyl acetate copolymer, 4 parts by weight of polybutyl methacrylate, 1 part of stearic acid, and 4 parts of bis (2-ethylhexyl) phthalate) The mixture was kneaded at 100 ° C. for 3 hours using a 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. Subsequently, the obtained kneaded material was granulated with an extruder to obtain a pellet-shaped molding resin composition. Table 3 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  Next, an extruded product was obtained in the same manner as in Example 1. The extrusion pressure was 5 MPa and the extrusion speed was 13 mm / sec. The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 3 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

Comparative Example 3
An apparently filling rate of 40% alumina balls having a Vickers hardness of 1200 and a ball diameter of 10 mm was placed in a 10 L nylon pot. Next, 100 parts by weight of yttrium oxide powder, 400 parts by weight of toluene, and 200 parts by weight of ethanol were added, and ball mill mixing was performed for 16 hours to obtain a sintering aid solution (dispersion).

  The obtained sintering aid solution was dried with a spray dryer to obtain a granular sintering aid.

  100 parts by weight of aluminum nitride powder, 5 parts by weight of the above granular yttrium oxide, 12 parts by weight of ethylene-vinyl acetate copolymer, 1.0 part of stearic acid, 4 parts of bis (2-ethylhexyl) phthalate were added to a Banbury mixer (Toyo Using a Labo plast mill model 100C mixer type B-250) manufactured by Seiki, the mixture was 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 molding resin composition. Table 3 shows the average particle diameter (Dn) and the maximum particle diameter (Dmax) of yttrium oxide in the obtained resin composition for molding.

  Next, an extruded product was obtained in the same manner as in Example 1. The extrusion pressure was 5 MPa and the extrusion speed was 13 mm / sec.

  The obtained extrusion-molded body was heated at a rate of 10 ° C./hour in an air atmosphere, degreased at 500 ° C. for 5 hours, and sintered at 1730 degrees in a nitrogen atmosphere for 6 hours to obtain a sintered body. It was. Table 3 shows the final blending ratio and viscosity of the molding resin composition, the density of the extruded molded body, the bending strength of the sintered body, and the measurement results of the thermal conductivity.

  By using the molding resin composition obtained by the method of the present invention, it is possible to obtain with good productivity an aluminum nitride sintered body to which an extrusion molding method such as a rod shape, a prismatic shape, a pipe shape, or a sheet shape can be applied. . 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 (6)

In obtaining a composition containing the thermoplastic resin, the aluminum nitride powder and the sintering aid by melting and kneading the aluminum nitride powder, the sintering aid and the thermoplastic resin, at least a part of the thermoplastic resin is baked. A method for producing an aluminum nitride molding resin composition, comprising preparing a preliminary dispersion with a binder and then subjecting the preliminary dispersion to the melt-kneading. The production method according to claim 1, wherein the preliminary dispersion is prepared by dispersing at least a part of the thermoplastic resin and the sintering aid in an organic solvent and then removing the organic solvent. The production method according to claim 2, wherein at least a part of the thermoplastic resin and the sintering aid are dispersed in an organic solvent by wet grinding. The production method according to claim 2, wherein the organic solvent is removed by spray drying. The resin composition for molding aluminum nitride 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 aluminum nitride powder. The manufacturing method as described in any one of 1-4. An aluminum nitride molding resin composition obtained by the production method according to claim 1.