JP2010065064A - Thermally conductive material, thermally conductive sheet, inter-laminar insulation film, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermally conductive material for accurately controlling a heat-transfer pathway and also having high thermal conductivity, flexibility and processability by spontaneously and selectively incorporating a thermal conductive fine particle in the heat-transfer pathway controlled by a phase-separation structure in a high molecule (polymer) blend by performing heating after film-formation without requiring a specific step. <P>SOLUTION: The thermally conductive material has a structure that the thermally conductive fine particle is dispersed in the polymer matrix. The polymer forming the polymer matrix is a polymer blend containing two kinds or more of polymer components, the polymer blend forms a cylinder type or a co-continuation type phase-separation structure, and the fine particle biasedly exists in one phase. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat conductive material and a method for producing the same, and more particularly to a heat conductive material excellent in heat dissipation, heat resistance, and workability. Specifically, two or more types of polymer phases are dispersed to form a cylinder-type or co-continuous phase separation structure, and thermally conductive fine particles are unevenly distributed in one phase, and a heat-conductive material having excellent heat dissipation and a method for producing the same About.

  In recent years, electronic components such as CPUs and ICs used in electronic devices and the like have increased power consumption and heat generation due to improved integration and speeding up of operations. Therefore, the heat dissipation countermeasure is a big problem. Further, in large-scale LSIs that require higher power, higher speed, and higher frequency than ordinary ICs such as power devices, improvement in thermal conductivity of interlayer insulating films between multilayer copper wirings is required.

Conventionally, in electronic equipment, etc., in order to suppress the temperature rise of electronic components during its use,
A heat sink using a metal plate having high thermal conductivity such as copper or aluminum is used. The heat sink conducts heat generated by the electronic component and releases the heat from the surface due to a temperature difference from the outside air. In order to efficiently transfer the heat generated from the electronic component to the heat sink, the heat sink needs to be in close contact with the electronic component. A heat conduction sheet or the like is used as an interface between the electronic component and the heat sink to efficiently heat the electronic component. Conducting. In order to efficiently transfer heat generated from the electronic component to the heat sink, it is important that the thermal conductivity in the thickness direction of the sheet is high.

  As such a heat conductive sheet, conventionally, a polymer material containing a metal oxide such as aluminum oxide, a metal nitride such as aluminum nitride, heat conductive fine particles such as silicon carbide, carbon black, etc. In addition, an elastic polymer substance that contains heat conductive fibers such as metal fibers and carbon fibers is known.

  However, in the conventional heat conductive sheet containing the heat conductive fine particles, a polymer substance is interposed between the heat conductive fine particles, that is, the heat conduction is high in addition to the heat conductive fine particles. Since the structure of the heat transfer path is carried out through a molecular substance and is not linear but complicated, the high thermal conductivity of the heat conductive fine particles themselves cannot be fully exhibited. The heat conductive sheet itself does not necessarily have high heat conductivity. Further, in order to increase the thermal conductivity of the thermal conductive sheet, it is conceivable to increase the ratio of the thermal conductive fine particles contained in the polymer substance. However, such a thermal conductive sheet has a hardness of Since it is high and inflexible, the degree of difficulty in processing is high, and it becomes difficult to sufficiently adhere the object to be processed.

  Furthermore, since it is desirable that the heat conductive sheet is insulative, when using electrically conductive (conductive) heat conductive fine particles such as carbon black, the ratio of the particles cannot be increased.

  Aiming to achieve both high thermal conductivity and flexibility, Patent Document 1 discloses a polymer that becomes a sea by using a polymer blend in which at least two polymer phases are dispersed to form a sea-island phase separation structure. A method is disclosed in which a thermally conductive filler is unevenly distributed in a phase to give flexibility to a polymer phase serving as another island.

  Moreover, in order to improve the thermal conductivity in the thickness direction, in Patent Document 2, in the sheet base material made of a polymer material having flexibility, the thermally conductive fine particles and the thermally conductive fibers exhibiting magnetism are in the thickness direction. And a method of containing the thermally conductive fine particles and the thermally conductive fibers by forming a chain of the thermally conductive fine particles and a heat transfer path extending in the thickness direction by the thermally conductive fibers. Even if the content ratio is small, the thermal conductivity in the thickness direction is improved.

  Further, Patent Document 3 discloses a method for increasing the thermal conductivity in the thickness direction by controlling the orientation of rigid molecular chains of the thermo-liquid crystalline polymer in a certain direction.

JP 2005-255867 A JP 2003-26828 A JP 2004-43629 A

  However, in Patent Document 1, although a polymer blend having a sea-island phase separation structure is provided with flexibility in a phase serving as an island, the heat conductive fine particles are uniformly dispersed in the phase serving as a sea. Therefore, the heat transfer path cannot be precisely controlled, and in Patent Documents 2 and 3, in order to arrange the heat conductive particles or the heat conductive fibers in the thickness direction, A special process for applying a magnetic field in a specific direction is necessary, and this process has a problem that the workability and productivity of the product are lowered.

  This invention is made | formed in view of such a subject, and does not require a special process, By heating after film forming, a heat conductive fine particle is made into a polymer (polymer) blend. A heat-conducting material that combines high heat conductivity, flexibility, and workability with precise control of the heat-transfer path by including it spontaneously and selectively in the heat-transfer path controlled by the phase separation structure. It is to provide. Moreover, the objective of this invention is providing the manufacturing method which can manufacture the said heat conductive material easily.

As a result of intensive studies to achieve the above object, the present inventors can achieve the above object by unevenly dispersing thermally conductive fine particles in a polymer matrix using a specific polymer blend system. As a result, the present invention has been completed.

The present invention has been made on the basis of the above knowledge, and is a heat conductive material having a structure in which heat conductive fine particles are dispersed in a polymer matrix, and the polymer forming the polymer matrix includes: A polymer blend comprising two or more polymer components, wherein the polymer blend forms a cylindrical or co-continuous phase separation structure, and the fine particles are unevenly distributed in one polymer phase. A conductive material is provided. Here, the uneven distribution means that a large amount of thermally conductive fine particles are precipitated in one polymer phase, and it is not necessary to deposit only in one polymer phase.
Examples of the heat conductive fine particles include metallic fine particles.
The polymer blend contains, for example, two or more polymer components having different affinity with the precursor of the heat conductive fine particles or the heat conductive fine particles.
Examples of the polymer blend include a polymer component having a heat resistance of 200 ° C. or higher or a precursor polymer component thereof.

The polymer blend includes a polymer component containing a sulfur atom in the molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. Can be mentioned.
The polymer blend includes a polymer component containing a disulfide bond in a molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. Can be mentioned.
The polymer blend includes a polymer component containing a sulfide bond in the molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. Can be mentioned.

The present invention also provides a precursor of thermally conductive fine particles that are soluble in an organic solvent in a polymer blend solution containing two or more polymer components and capable of forming a cylindrical or co-continuous phase separation structure. And a step of forming a film by forming a solution of the above polymer blend into a film, and then causing the thermally conductive fine particles or fine particle aggregates to be unevenly distributed in one polymer phase by heating and spontaneously depositing them. The manufacturing method of the said heat conductive material characterized by these. The precursor of the heat conductive fine particles is selected from the group consisting of inorganic metal compounds, organometallic compounds, complexes of inorganic metal compounds and organometallic compounds, and complexes of organometallic compounds and organometallic compounds. Can be mentioned.
Examples of the polymer blend include those containing two or more polymer components having different affinity with the precursor of the heat conductive fine particles or the heat conductive fine particles.
Examples of the polymer blend include a polymer component having a heat resistance of 200 ° C. or higher or a precursor polymer component thereof.

Examples of the polymer blend include those containing a polymer component containing a sulfur atom in the molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed.
Examples of the polymer blend include those containing a polymer component containing a disulfide bond in the molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed.
Examples of the polymer blend include those containing a polymer component containing a sulfide bond in the molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed.

Moreover, this invention provides the heat conductive sheet produced using the said heat conductive material.
Moreover, this invention provides the heat conductive sheet produced using the heat conductive material obtained by the manufacturing method of the said heat conductive material.
Moreover, this invention provides the interlayer insulation film produced using the said heat conductive material.
Moreover, this invention provides the interlayer insulation film produced using the heat conductive material obtained by the manufacturing method of the said heat conductive material.

  The heat conductive material of the present invention comprises two or more polymer components having different affinity with the precursor of the heat conductive fine particles or the heat conductive fine particles, and the heat conductive fine particles are unevenly distributed in one polymer phase. In addition, by forming a cylindrical or bicontinuous phase separation structure, it has the effect of orienting the heat conductive fine particles in a certain direction, so even if the content ratio of the heat conductive fine particles is low, it has high heat conduction characteristics. Obtainable. In addition, the heat conductive material of the present invention is easy to process and handle, and is excellent in heat resistance, moisture resistance, flexibility, and mechanical strength, and mainly reduces the cost of the heat conductive sheet and the high heat conductive interlayer insulating film. And can contribute to the efficiency of the production process.

The present invention is described in detail below.
The heat conductive material of the present invention is a heat conductive material including a structure in which heat conductive fine particles are dispersed in a polymer matrix. The polymer forming the polymer matrix is composed of two or more kinds of polymers. A polymer blend containing components, which can form a cylindrical or co-continuous phase separation structure.

The polymer constituting the polymer matrix constituting the thermally conductive material of the present invention is a polymer blend containing two or more polymer components, and the polymer blend forms a cylindrical or bicontinuous phase separation structure. It is possible. Since the polymer blend can form a cylindrical or bicontinuous phase separation structure, the thermally conductive fine particles are efficiently incorporated into one phase when the cylindrical or bicontinuous phase separation structure is formed. Therefore, the performance as a heat conductive material can be sufficiently exhibited.

  Therefore, the polymer blend preferably contains two or more polymer components having different affinity with the precursor of the heat conductive fine particles or the heat conductive fine particles constituting the heat conductive material. In the following, when the affinity between the polymer component and the thermally conductive fine particle precursor is described, the affinity between the polymer component and the thermally conductive fine particle is included synonymously. In addition, in order to efficiently incorporate the heat conductive fine particles into one phase when the cylindrical or bicontinuous phase separation structure is formed, two types of affinity with the heat conductive fine particle precursor are greatly different. It is preferable to use a polymer. That is, it is preferable to contain a polymer component having a high affinity with the precursor of the heat conductive fine particles and a polymer component having a low affinity with the precursor of the heat conductive fine particles. Thus, the heat conductive material of the present invention contains a polymer component having a high affinity for the precursor of the heat conductive fine particles and a polymer component having a low affinity for the precursor of the heat conductive fine particles. The polymer blend forms a cylindrical or co-continuous phase separation structure. In the present invention, the polymer component having a high affinity with the precursor of the heat conductive fine particle and the polymer component having a low affinity with the precursor of the heat conductive fine particle may each include two or more kinds. Good. Examples of the polymer having high affinity with the precursor of the heat conductive fine particle, particularly the precursor of the metal fine particle, include, for example, a polymer having a disulfide bond or a sulfide bond in the molecular structure, that is, a sulfur atom in the molecular structure. May be used. In addition, examples of the polymer having a low affinity with the heat conductive fine particle precursor, particularly the metallic fine particle precursor, include a polymer containing a large number of fluorine atoms in the molecular structure. Such a blend of two kinds of polymers has a large difference in affinity with the metallic fine particle precursor described later, so when the blended product dissolved and mixed in an appropriate solvent is formed and dried, The polymer blend forms a cylindrical or co-continuous phase separation structure. Also, even if no noticeable co-continuous phase separation structure is observed during film formation / drying, use it when a co-continuous phase separation structure is manifested in the subsequent thermal curing (thermal imidization) process. can do. In this process, when a cylindrical or bicontinuous phase separation structure is formed, the precursor of the metallic fine particles is efficiently incorporated into the polymer phase having a high affinity with the metallic fine particle precursor, and as a result, the metal Fine particles are precipitated at a high concentration. The polymer containing a sulfur atom in the molecular structure and the polymer component containing a fluorine atom in the molecular structure will be described later.

  As will be described later, since the heat conductive material of the present invention is produced by precipitating heat conductive fine particles (metallic fine particles) by heat treatment, the polymer preferably has a heat resistance of 200 ° C. or higher. A polymer is preferable, and an organic polymer having a heat resistance of 270 ° C. or higher, which is a standard for solder heat resistance, or a precursor polymer thereof is more preferable. Examples of such a polymer include aromatic polyimide, aromatic polyamide, aromatic polybenzoxazole, aromatic polybenzimidazole, aromatic polybenzothiazole, aromatic polycarbonate, and precursors thereof. Body polymer and the like.

  Examples of the polymer used in the present invention include polyimide and its precursor polymer such as polyamic acid and polyamic acid ester, and basically all polyamic acids can be used, but the above-mentioned characteristics are provided. Those are preferably used. Examples of the polymer to be used include polyamic acid, polyamic acid salt, polyamic acid esterified product, polyimide and the like produced from the following tetracarboxylic acid or a derivative thereof and diamine. Examples of tetracarboxylic acid and acid dianhydrides, acid chlorides, esterified compounds and the like as derivatives thereof include the following. In the thermally conductive material of the present invention, as described above, a sulfur-containing polyimide is preferable as the polymer having a high affinity with the metallic fine particles when the cylindrical or bicontinuous phase separation structure is formed. As the polymer having a low affinity with the conductive fine particles, a fluorine-containing polyimide containing fluorine in the molecular structure is preferable. Each will be described below.

  Examples of tetracarboxylic acids for obtaining fluorine-containing polyimides containing fluorine in the molecular structure include (trifluoromethyl) pyromellitic acid, di (trifluoromethyl) pyromellitic acid, and di (heptafluoropropyl) pyromellitic. Acid, pentafluoroethyl pyromellitic acid, bis {3,5-di (trifluoromethyl) phenoxy} pyromellitic acid, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 5,5'- Bis (trifluoromethyl) -3,3 ′, 4,4′-tetracarboxybiphenyl, 2,2 ′, 5,5′-tetrakis (trifluoromethyl) -3,3 ′, 4,4′-tetracarboxy Biphenyl, 5,5′-bis (trifluoromethyl) -3,3 ′, 4,4′-tetracarboxydiphenyl ether 5,5′-bis (trifluoromethyl) -3,3 ′, 4,4′-tetracarboxybenzophenone, bis {(trifluoromethyl) dicarboxyphenoxy} benzene, bis {(trifluoromethyl) dicarboxyphenoxy } (Trifluoromethyl) benzene, bis (dicarboxyphenoxy) (trifluoromethyl) benzene, bis (dicarboxyphenoxy) bis (trifluoromethyl) benzene, bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) benzene, 2 , 2-bis {4- (3,4-dicarboxyphenoxy) phenyl} hexafluoropropane, bis {(trifluoromethyl) dicarboxyphenoxy} biphenyl, bis {(trifluoromethyl) dicarboxyphenoxy} bis (trifluoro Methyl) Biphenyl, bis {(trifluoromethyl) dicarboxyphenoxy} diphenyl ether, bis (dicarboxyphenoxy) bis (trifluoromethyl) biphenyl, difluoropyromellitic acid, 1,4-bis (3,4-dicarboxytrifluorophenoxy) Tetrafluorobenzene, 1,4-bis (3,4-dicarboxytrifluorophenoxy) octafluorobiphenyl, pyromellitic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4'-biphenyltetracarboxylic acid, 2,3,2 ', 3'-biphenyltetracarboxylic acid, 3,3', 4,4'-tetracarboxydiphenyl ether, 2,3 ', 3,4'-tetracarboxydiphenyl ether 3,3 ', 4,4'-benzophenone tetracarboxylic 2,3,6,7-tetracarboxynaphthalene, 1,4,5,7-tetracarboxynaphthalene, 1,4,5,6-tetracarboxynaphthalene, 3,3 ′, 4,4′-tetracarboxydiphenylmethane 2,2-bis (3,4-dicarboxyphenyl) propane, 3,4,9,10-tetracarboxyperylene, 2,2-bis {4- (3,4-dicarboxyphenoxy) phenyl} propane, Examples include butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, bis (3,4-dicarboxyphenyl) dimethylsilane, 1,3-bis (3,4-dicarboxyphenyl) tetramethyldisiloxane, and the like.

Examples of the diamine include 4- (1H, 1H, 11H-eicosafluoroundecanoxy) -1,3-diaminobenzene, 4- (1H, 1H-perfluoro-1-butanoxy) -1,3-diamino Benzene, 4- (1H, 1H-perfluoro-1-heptanoxy) -1,3-diaminobenzene, 4- (1H, 1H-perfluoro-1-octanoxy) -1,3-diaminobenzene, 4-pentafluoro Phenoxy-1,3-diaminobenzene, 4- (2,3,5,6-tetrafluorophenoxy) -1,3-diaminobenzene, 4- (4-fluorophenoxy) -1,3-diaminobenzene, 4- (1H, 1H, 2H,
2H, -perfluoro-1-hexanoxy) -1,3-diaminobenzene, 4- (1H,
1H, 2H, 2H-perfluoro-1-dodecanoxy) -1,3-diaminobenzene, 2,5-diaminobenzotrifluoride, bis (trifluoromethyl) phenylenediamine, diaminotetra (trifluoromethyl) benzene, diamino ( Pentafluoroethyl) benzene, 2,5-diamino (perfluorohexyl benzene, 2,5-diamino (perfluorobutyl) benzene, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, octa Fluorobenzidine, 3,3′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 2,2-bis (p-aminophenyl) hexafluoropropane, 1,3-bis (anilino) hexafluoropropane, 1,4-bis (anilino) octafluorobutane, 1,5- (Anilino) decafluoropentane, 1,7-bis (anilino) tetradecafluoroheptane, 2,2′-bis (trifluoromethyl) -4,4′-diaminodiphenyl ether, 3,3′-bis (trifluoro) Methyl) -4,4′-diaminodiphenyl ether, 3,3 ′, 5,5′-tetrakis (trifluoromethyl) -4,4′-diaminodiphenyl ether, 3,3′-bis (trifluoromethyl) -4, 4′-diaminobenzophenone, p-bis (4-amino-2-trifluoromethylphenoxy) benzene, bis (aminophenoxy) bis (trifluoromethyl) benzene, bis (aminophenoxy) tetrakis (trifluoromethyl) benzene, 2 , 2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, 2 2-bis {4- (3-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- (2-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- (4-amino) Phenoxy) -3,5-dimethylphenyl} hexafluoropropane, 2,2-bis {4- (4-aminophenoxy) -3,5-ditrifluoromethylphenyl} hexafluoropropane, 4,4′-bis (4 -Amino-2-trifluoromethylphenoxy) biphenyl, 4,4'-bis (4-amino-3-trifluoromethylphenoxy) biphenyl, 2,2-bis {4- (4-amino-3-trifluoromethyl) Phenoxy) phenyl} hexafluoropropane, bis {(trifluoromethyl) aminophenoxy} biphenyl, bis [{(to Fluoromethyl) aminophenoxy} phenyl] hexafluoropropane, bis [{2- (aminophenoxy) phenyl} hexafluoroisopropyl] benzene, bis (2,3,5,6) -tetrafluoro-4-aminophenyl) ether, 1,3-diaminotetrafluorobenzene, 1,4-diaminotetrafluorobenzene, 4,4′-bis (tetrafluoroaminophenoxy) octafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene 2,4-diaminoxylene, 2,4-diaminodurene, 2,5-diaminotoluene, 2,3,5,6-tetramethyl-p-phenylenediamine, benzidine, 2,2′-dimethylbenzidine, 3, 3'-dimethylbenzidine, 3,3'-dimethoxy Benzidine, 2,2′-dimethoxybenzidine, 3,3 ′, 5,5′-tetramethylbenzidine, 3,3′-diacetylbenzidine, 4,4′-oxydianiline, 3,4′-oxydianiline, 4,4'-diaminodiphenylmethane, 2,2-bis (p-aminophenyl) propane, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenylmethane 1,2-bis (anilino) ethane, 4,4′-diamino-p-terphenyl, 1,4-bis (p-aminophenyl) benzene, 4,4′-diamino-p-quaterphenyl, 4, 4′-bis (p-aminophenoxy) biphenyl, 2,2-bis {4- (p-aminophenoxy) phenyl} propane, 4,4′-bis (3-aminophenoxyphenyl) Diphenylsulfone, diaminoanthraquinone, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,4-bis (3-aminopropyldimethylsilyl) benzene And bis (4-aminophenyl) diethylsilane.

  As described above, in the thermally conductive material of the present invention, as a polymer having a low affinity with metallic fine particles when a cylindrical or bicontinuous phase separation structure is formed, fluorine is included in the molecular structure. Since the fluorine-containing polyimide to contain is preferable, among the tetracarboxylic acid and diamine mentioned above, the fluorine-containing polyimide obtained using the tetracarboxylic acid containing fluorine or the diamine containing fluorine is preferable. Either tetracarboxylic acid or diamine may contain fluorine, and either one may contain fluorine.

Examples of the tetracarboxylic acid for obtaining a sulfur-containing polyimide containing a sulfur atom in the molecular structure include 3,3 ′, 4,4′-tetracarboxydiphenylsulfone, thiathrene-2,3,7,8- Tetracarboxylic acid-5,5,10,10-tetraoxide, 2,2 ′, 3,3′-tetracarboxydiphenyl thioether, 2,3,3 ′, 4′-tetracarboxydiphenyl thioether, 3,3 ′, 4,4′-tetracarboxydiphenylthioether, pyromellitic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 2,3,2 ′ , 3′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-tetracarboxydiphenyl ether, 2,3 ′, 3,4′-tetracarboxydiphenyl ether, 3, ', 4,4'-benzophenone tetracarboxylic acid, 2,3,6,7-tetracarboxynaphthalene, 1,4,5,7-tetracarboxynaphthalene, 1,4,5,6-tetracarboxynaphthalene, 3, 3 ′, 4,4′-tetracarboxydiphenylmethane, 2,2-bis (3,4-dicarboxyphenyl) propane, 3,4,9,10-tetracarboxyperylene, 2,2-bis {4- (3 , 4-Dicarboxyphenoxy) phenyl} propane, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, bis (3,4-dicarboxyphenyl) dimethylsilane, 1,3-bis (3,4-dicarboxyphenyl) tetra And methyldisiloxane.

Examples of the diamine include 2,2′-benzidine disulfonic acid, 2,2′-dithiodianiline, 4,4′-dithiodianiline, 4,4′-thiodianiline, 2,2′-diaminodiphenyl sulfide, 3 , 3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 4,4′-bis (4-amino-2-trifluoromethylphenoxy) diphenylsulfone, 4,4′-bis (3-amino-5) -Trifluoromethylphenoxy) diphenylsulfone, bis (2,3,5,6) -tetrafluoro-4-aminophenyl) sulfide, 4,4'-bis (3-aminophenoxy) diphenylsulfone, 4,4'- Bis (4-aminophenoxy) diphenylsulfone, 2,2-bis [4- {2- (4
-Aminophenoxy) ethoxy} phenyl] sulfone, 3,3′-disulfonic acid-bis {
4- (3-aminophenoxy) -phenyl} sulfone, 3,3 ′, 5,5′-tetramethyl-bis {4- (4-aminophenoxy) phenyl} sulfone, 3,7-diamino-2,
8 (6) -dimethyldibenzothiophenesulfone, 4,4′-bis (6-aminonaphthoxy) diphenylsulfone, 5,5′-dimethylbenzidine-2,2′-disulfonic acid, 4
, 4′-diaminodiphenyl ether-2,2′-disulfonic acid, 4,4′-bis (4-
Isocyanatophenoxy) diphenylsulfone, 4,4′-bis (3-isocyanatophenoxy) diphenylsulfone, 3- (2 ′, 4′-diaminophenoxy) propanesulfonic acid, 2,2′-bis (sulfopropoxy)- 4,4′-diaminobiphenyl, 3,
3′-bis (sulfopropoxy) -4,4′-diaminobiphenyl, 9,9-bis (4-
Aminophenyl) fluorene-2,7-disulfonic acid, 2,5-diaminobenzenesulfonic acid, 4,5-diamino-6-hydroxy-2-mercaptopyrimidine, 2,2′-bis (4-aminophenoxy) biphenyl- 5,5′-disulfonic acid, 4,4′-bis (4-
Aminophenoxy) biphenyl-3,3′-disulfonic acid, 2-methyl-3,5-diaminodiphenyl sulfide, 3,3 ′, 5,5′-benzidinetetrathiol, 3,3′-
Benzidine dithiol, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,4-diaminoxylene, 2,4-diamino Durene, 2,5-diaminotoluene, 2,3,5,6-tetramethyl-p-phenylenediamine, benzidine, 2,2′-
Dimethylbenzidine, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 2,2′-dimethoxybenzidine, 3,3 ′, 5,5′-tetramethylbenzidine, 3,3′-diacetylbenzidine, 4 , 4′-oxydianiline, 3,4′-oxydianiline, 4,4′-diaminodiphenylmethane, 2,2-bis (p-aminophenyl) propane, 3,3′-dimethyl-4,4′- Diaminodiphenyl ether, 3,3′-dimethyl-4,4′-diaminodiphenylmethane, 1,2-bis (anilino) ethane, 4,4′-diamino-p-terphenyl, 1,4-bis (p-aminophenyl) ) Benzene, 4,4′-diamino-p-quarterphenyl, 4,4′-bis (p-aminophenoxy) biphenyl, 2,2-bis {4- (p-aminophenoxy) ) Phenyl} propane, 4,4′-bis (3-aminophenoxyphenyl) diphenylsulfone, diaminoanthraquinone, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 1,3-bis (3-aminopropyl) tetra Examples include methyldisiloxane, 1,4-bis (3-aminopropyldimethylsilyl) benzene, and bis (4-aminophenyl) diethylsilane.

  As described above, in the thermally conductive material of the present invention, the polymer having a high affinity with the metallic fine particles when the cylindrical or bicontinuous phase separation structure is formed includes a sulfur atom. Since it is preferable to use a sulfur polyimide, a polyimide obtained by using a tetracarboxylic acid containing a sulfur atom or a diamine containing a sulfur atom among the tetracarboxylic acids and diamines described above is preferable. Either tetracarboxylic acid or diamine may contain a sulfur atom, and either one may contain a sulfur atom. In the thermally conductive material of the present invention, the polymer blend needs to form a cylindrical or co-continuous phase separation structure. Accordingly, a polymer having a low affinity with the metallic fine particles and a polymer having a high affinity with the metallic fine particles are selected so as not to be compatible with each other at the molecular level. That is, in a system in which two or more kinds of polymers used in the present invention are mixed, a combination in which at least one component forms a phase (domain) having a size of nanometer or more and does not become a single phase is selected. Thus, as a combination of polymers that are not compatible with each other at the molecular level, for example, a combination of polyimides represented by the following general formula (I) is preferably used.

In the general formula (I), n and n ′ are arbitrary numbers. Further, R ¹ (the following formulas (1) to (9)) and R ² (the following formulas (10) to (17)) include the following structures containing a sulfur atom. However, a structure containing a sulfur atom in either R ¹ or R ² may be used, and a structure containing a sulfur atom in both R ¹ and R ² is not necessarily used.

In the general formula (I), R ³ (following formulas (18) to (25)) and R ⁴ (following formulas (26) to (36)) include the following structures containing fluorine. However, a structure containing fluorine in either R ³ or R ⁴ may be used, and a structure containing fluorine in both R ¹ and R ² is not necessarily used.

  Although there is no restriction | limiting in particular in the method of manufacturing a polyimide from tetracarboxylic acid and diamine, For example, it can manufacture by heat-ring-closing the polyamic acid obtained by polycondensing the said tetracarboxylic acid and diamine. There is no restriction | limiting in particular in the method of carrying out a heat ring closure, A conventionally well-known method is used. In the heat conductive material of this invention, it can be set as a polyimide using a tetracarboxylic acid and diamine by the method as mentioned later.

Next, the thermally conductive fine particles dispersed in the polymer matrix will be described.
As the heat conductive fine particles dispersed in the polymer matrix of the heat conductive material of the present invention, one or more fine particles comprising noble metal, base metal, metal oxide, metal nitride, metal halide, silicon carbide, etc. , Also referred to as metallic fine particles). As a metallic dopant which becomes a precursor of such metallic fine particles, an organic solvent (for example, N-methyl-2) which can dissolve the above polymer (polyimide or polyamic acid which is a precursor thereof and derivatives thereof) is used. -Polar organic solvents such as pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, and γ-butyrolactone are generally suitable, but there is no particular limitation as long as both the polymer and the metallic dopant are dissolved. For example, metal halides, metal oxides, metal nitrides, metal nitric acid compounds, metal acetic acid compounds, metal trifluoroacetic acid compounds, metal acetylacetone compounds, metal trivalent compounds, and the like. Examples thereof include fluoroacetylacetone compounds and metal hexafluoroacetylacetone compounds. Examples of the metal include silver, copper, gold, aluminum, palladium, iron, chromium, nickel, manganese, tin, cobalt, titanium, magnesium, and lithium. In addition, organometallic complexes obtained by mixing acetylacetone, 1,1,1-trifluoroacetylacetone, 1,1,1,5,5,5-hexafluoroacetylacetone with the above compound can also be used. .

The size (diameter) of the metallic fine particles dispersed in the polymer matrix of the heat conductive material of the present invention is not particularly limited as long as it does not significantly affect the surface shape and surface roughness of the heat conductive material. However, it is usually preferably about 1 nm to 1 μm, and more preferably about 5 nm to 100 nm.
The metallic fine particles have a one-dimensional (anisotropic) shape in which individual fine particles are stretched in one direction, or aggregates in which fine particles not having a one-dimensional shape are arranged one-dimensionally. May be formed. Here, the case where fine particles (groups) having a one-dimensional (anisotropic) shape are further arranged one-dimensionally is included.

Although there is no restriction | limiting in particular in the manufacturing method of the heat conductive material of this invention, It can manufacture with the manufacturing method of the heat conductive material mentioned later.
Although there is no restriction | limiting in particular in the thickness of the heat conductive material of this invention, Usually, it is about 10-50 micrometers.

Next, the manufacturing method of the heat conductive material of this invention is demonstrated.
The method for producing a heat conductive material according to the present invention is a heat-soluble material that is soluble in an organic solvent in a solution of a polymer blend that contains two or more polymer components and can form a cylindrical or bicontinuous phase separation structure. The step of dissolving the precursor of conductive fine particles, and after forming the film of the polymer blend solution into a film, the heat conductive fine particles or fine particle aggregates are unevenly distributed in one polymer phase by heating, and spontaneously It has the process to make it precipitate.

  In the manufacturing method of the heat conductive material of this invention, the solution of the polymer blend which contains two or more types of polymer components and can form a cylinder type or a bicontinuous type phase-separated structure is used. As such a polymer blend, one containing the above-described polymer component is used.

  In the manufacturing method of the heat conductive material of this invention, the said polymer is used as a raw material. Examples of solvents that can dissolve these polymers or their precursor polymers include polar organic compounds such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, and γ-butyrolactone. A solvent is generally suitable, but there is no particular limitation as long as both the polymer and the precursor of the heat conductive fine particles are dissolved. In the method for producing a heat conductive material of the present invention, the above-described polymer component is used. Therefore, when this polymer component is dissolved and mixed in the above solvent, the polymer blend is formed when the film is formed and dried. However, it is necessary to select a polymer raw material in such a combination that forms a cylinder type or bicontinuous phase separation structure.

In the method for producing a thermally conductive material of the present invention, a phase having a high affinity with a precursor of metallic fine particles (hereinafter referred to as the present specification) when dispersed to form a cylindrical or bicontinuous phase separation structure. (Hereinafter also referred to as “high metal affinity phase”) and a phase having low affinity between the polymer solution and the precursor of the metallic fine particles (hereinafter also referred to as “low metal affinity phase” in this specification). It is preferable to mix a polymer constituting () into a polymer blend solution. In the present invention, two or more polymer components may be used as the polymer constituting the high metal affinity phase, and two or more polymer components may be used as the polymer constituting the low metal affinity phase. It may be used.
The polymer solution constituting the low metal affinity phase is added to the polymer solution constituting the high metal affinity phase, and then stirred to prepare a polymer blend solution. This stirring generally forms a phase separation structure dispersed at a nanometer level to a micron level. When using a normal stirring bar and a stirrer (stirrer), the stirring operation is preferably performed for 20 minutes to 24 hours. On the other hand, when using a rotating / revolving mixer, stirring operation within 20 minutes is often sufficient. At this time, when a polycondensation polymer such as a polyamic acid or a polyamide ester is used, a block co-polymerization is caused by a main chain exchange reaction represented by an amide exchange reaction or a transesterification reaction during the stirring. Since it becomes a polymer, if the stirring time is too long, the phase separation structure and morphology (domain size) may change.

  Next, a precursor of thermally conductive fine particles soluble in an organic solvent is dissolved in the solution of the polymer blend. Here, examples of the heat conductive fine particles include one or more fine particles (hereinafter also referred to as metallic fine particles) made of noble metal, base metal, metal oxide, metal nitride, metal halide, silicon carbide, and the like. As a precursor of these metallic fine particles, for example, a kind selected from the group consisting of inorganic metal compounds, organometallic compounds, complexes of inorganic metal compounds and organometallic compounds, and complexes of organometallic compounds and organometallic compounds (Hereinafter referred to as “metallic dopant” in the present specification). As a metallic dopant, what was demonstrated in the metallic fine particle mentioned above is mentioned.

After the metallic dopant is added to the polymer blend solution, it is stirred until it appears to be compatible. Stirring is preferably performed for 1 hour or longer. By stirring, the metallic dopant is preferentially incorporated into the high metal affinity phase, and the cylindrical or bicontinuous phase separation structure of the polymer blend plays a role in forming a heat conduction path during subsequent heating. For this reason, as described above, the polymer blend preferably contains two or more types of polymer components having different affinity with the metallic fine particles constituting the heat conductive material. In the case of using a precursor polymer, a combination in which the precursor polymer has different affinity with the precursor of the metallic fine particles may be selected. In addition, when a cylinder-type or bicontinuous-type phase separation structure is formed, in order for the high metal affinity phase incorporating metal fine particles to function as an efficient heat conduction path, the high metal affinity phase is thick. It is preferable to use the mixture so that the ratio of the low metal affinity phase is as large as possible.
On the other hand, the metallic dopant is first added to the polymer solution that constitutes the high metal affinity phase, and after stirring to obtain a stable solution, the polymer solution that constitutes the low metal affinity phase is added thereto. It is also possible to prepare a polymer blend solution by stirring. Also by this mixing operation, a phase separation structure dispersed at a nanometer level to a micron level is formed.

  The mixing ratio of the polymer component constituting the high metal affinity phase and the polymer component constituting the low metal affinity phase is 20:80 to 80:20 (high metal affinity component: low metal affinity). It is preferable that it is about a sex component) grade. When the ratio of the high metal affinity phase is less than the above range, the high metal affinity phase may be discontinuous in the thickness direction. On the other hand, when the ratio exceeds the above range, the metallic fine particles are contained in the high metal affinity phase. Therefore, an efficient heat conduction path may not be formed. That is, since the mixing ratio of the polymer component and the polymer component constituting the low metal affinity phase is within the above range, the obtained heat conductive material forms a cylinder type or bicontinuous phase separation structure. To do.

  The mixing ratio of the polymer blend and the metallic dopant is preferably about 100: 5 to 100: 100 (polymer blend: metallic dopant) in terms of molar ratio. If the amount of the metallic dopant is less than the above range, the amount of precipitation of the metallic fine particles or the metallic fine particle aggregate may be insufficient, so that the thermal conductivity may not be sufficient. Insulating properties and flexibility may be reduced due to excessive aggregation of metallic fine particles.

  Moreover, although the said mixed solution contains the organic solvent mentioned above, it is preferable that content of an organic solvent is 70-95 mass% in a mixed solution. When the content of the organic solvent is less than the above range, the content of the polymer, the metallic fine particles or the metallic dopant becomes too thick, and the viscosity becomes too high, which may make stirring difficult. If it exceeds 1, the viscosity becomes too low and film molding may be difficult.

Next, a mixed solution (hereinafter referred to as a mixed solution) of the polymer blend and the metallic dopant is formed into a film.
Although there is no restriction | limiting in particular in the method of forming into a film and forming a film, For example, it can carry out by the spin coat method or the casting method using the said mixed solution. A thin film can be formed from a solution by spin coating or casting. The spin coating method and the casting method can be performed by a conventionally known method. In film formation, heating may be performed. When heating is performed, the temperature may be about room temperature (25 ° C.) to about 70 ° C.
After coating the above mixed solution on a substrate and forming a film to form a film, thermal imidization (dehydration ring closure by heating of polyamic acid) is performed by heat treatment, and at the same time, the metallic dopant is reduced by heat and metallic fine particles Alternatively, the fine particle aggregate can be selectively deposited in the high metal affinity phase. In this case, the temperature of the heat treatment is desirably sufficiently higher than the temperature at which the ring closure reaction is almost completed (about 200 ° C.).

According to the method for producing a thermally conductive material of the present invention, a cylindrical or bicontinuous phase separation structure is formed using two or more polymer phases having different affinity for metal, and metallic fine particles Alternatively, by selectively precipitating the fine particle aggregate in the high metal affinity phase, a heat transfer path is formed, and an excellent heat conductive material can be obtained.
Moreover, according to the manufacturing method of the heat conductive material of this invention, processing and handling are easy and the heat conductive material excellent in heat resistance, moisture resistance, a softness | flexibility, and mechanical strength can be obtained.

  Hereinafter, the present invention will be described more specifically by describing examples. However, the present invention is not limited to these examples.

Example 1
Polyamic acid synthesized from 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride (BPDA) and 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl (TFDB) (Polyimide precursor) N, N-dimethylacetamide solution (solid content concentration 12%) and polyamic acid synthesized from BPDA and 4,4′-dithiodianiline (DTDA) which is a diamine having a disulfide bond N, N-dimethylacetamide solution (solid content concentration 20%) was mixed and stirred at room temperature for 8 hours. The mixing ratio was BPDA / TFDB: BPDA / DTDA = 30: 70 in terms of molar ratio.

  Next, silver nitrate was added to the polymer blend and stirred for 8 hours. The mixing ratio is polymer blend: silver nitrate = 100: 20 in molar ratio. Next, the mixed solution was applied onto a silicon wafer by spin coating (spin coating), and the solvent was evaporated to such an extent that it could be removed by heat treatment at 70 ° C. for 1 hour in a nitrogen atmosphere. The film peeled off from the silicon wafer is attached on an aluminum plate, heated to 300 ° C. at a heating rate of 4.6 ° C./min, held for 90 minutes, and then allowed to cool to room temperature. A thermally conductive film was prepared.

  The heat conductive film obtained as described above was observed with an optical microscope, and it was confirmed that a cylindrical phase separation structure was developed in the thickness direction of the film. The image is shown in FIG. In FIG. 1, the portion shown in white is the high metal affinity phase 1, and the portion shown in black is the low metal affinity phase 2. In the X-ray energy analysis, it was confirmed that silver having no valence (metallic silver) was selectively deposited on the high metal affinity phase 1. The size of the phase separation structure formed by the two kinds of polymers was about 100 μm. Although the obtained film was slightly poor in flexibility and mechanical strength, it had sufficient insulating properties.

Example 2
Instead of the polyamic acid synthesized from BPDA and DTDA, an N, N-dimethylacetamide solution (solid content concentration 12%) of polyamic acid synthesized from BPDA and 4,4′-thiodianiline (SDA) was used. The same operation as in Example 1 was performed to prepare a heat conductive film having a thickness of about 15 μm. About the obtained heat conductive film, the cross-sectional image observation with a scanning electron microscope was performed, and it was confirmed that the bicontinuous phase-separation structure has expressed in the thickness direction of the film. The image is shown in FIG. In FIG. 2, the white portion is the high metal affinity phase 3, and the black portion is the low metal affinity phase 4. X-ray energy analysis confirmed that metallic silver was selectively deposited on the high metal affinity phase 3. The size of the phase separation structure formed by the two types of polymers was about 10 μm. In addition, the grain size of the silver crystallites estimated from the spectral width of the diffraction peak attributed to metallic silver observed by wide-angle X-ray diffraction was 6.3 nm. The obtained film had high insulating properties and sufficient flexibility and mechanical properties required for heat conductive sheets and interlayer insulating films.

Comparative Example 1
N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 12%) and N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and DTDA (solid content concentration 20) %) And stirred at room temperature for 8 hours. The mixing ratio was BPDA / TFDB: BPDA / DTDA = 30: 70 in terms of molar ratio. Next, the mixed solution was applied onto a silicon wafer by spin coating (spin coating), and the solvent was evaporated to such an extent that it could be removed by heat treatment at 70 ° C. for 1 hour in a nitrogen atmosphere. A film peeled off from a silicon wafer is attached on an aluminum plate, heated to 300 ° C. at a heating rate of 4.6 ° C./min, held for 90 minutes, and then allowed to cool to room temperature, thereby heat having a thickness of 23 μm. A conductive film was prepared.

Comparative Example 2
The same operation as in Comparative Example 1 except that an N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and SDA (solid content concentration 12%) was used instead of the polyamic acid synthesized from BPDA and DTDA. And a thermally conductive film having a thickness of about 16 μm was prepared.

Example 3
Silver nitrate was added to an N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and SDA (solid content concentration 15%) and stirred for 4 hours. Next, an N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 15%) was added and stirred for 4 hours. The mixing ratio was BPDA / TFDB: BPDA / SDA: silver nitrate = 50: 50: 20 in molar ratio. Next, the mixed solution was applied onto a silicon wafer by spin coating (spin coating), and the solvent was evaporated to such an extent that it could be removed by heat treatment at 70 ° C. for 1 hour in a nitrogen atmosphere. The film peeled off from the silicon wafer is attached on an aluminum plate, heated to 300 ° C. at a heating rate of 4.6 ° C./min, held for 90 minutes, and then allowed to cool to room temperature. A thermally conductive film was prepared.

  About the heat conductive film obtained as mentioned above, the cross-sectional image observation by a scanning electron microscope was performed, and it was confirmed that the bicontinuous type phase-separation structure has expressed in the thickness direction of the film. The image is shown in FIG. In FIG. 3, the white portion is the high metal affinity phase 5, and the black portion is the low metal affinity phase 6. The size of the phase separation structure formed by the two kinds of polymers was about 15 μm. The obtained film had high insulating properties and sufficient flexibility and mechanical properties required for heat conductive sheets and interlayer insulating films.

Comparative Example 3
Except that the mixing ratio of the polymer blend and silver nitrate was BPDA / TFDB: BPDA / SDA: silver nitrate = 70: 30: 20 in terms of molar ratio, the same operation as in Example 3 was performed, and the thermal conductivity having a thickness of about 30 μm. The film was adjusted. Although the thermal conductive film obtained as described above had high insulation and sufficient flexibility and mechanical properties required for the thermal conductive sheet and interlayer insulating film, a cross-sectional image obtained by a scanning electron microscope. As a result of observation, the two types of polymers formed a phase separation structure having a sea-island structure in which spherical BPDA / SDA phases having a diameter of about 5 μm were uniformly dispersed in the BPDA / TFDB phase. . The image is shown in FIG. In FIG. 4, the white portion is the high metal affinity phase 7, and the black portion is the low metal affinity phase 8.

Comparative Example 4
An N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 12%) is applied onto a silicon wafer by spin coating (spin coating), and at a temperature of 70 ° C. in a nitrogen atmosphere. The solvent was evaporated to such an extent that it could be removed by heat treatment for 1 hour. Thereafter, the temperature was raised to 300 ° C. at a rate of temperature rise of 4.6 ° / min, held for 90 minutes, and then allowed to cool to room temperature, thereby preparing a 13 μm thick thermally conductive film.

Comparative Example 5
Silver nitrate was added to an N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 12%) and stirred for 8 hours. The mixing ratio is BPDA / TFDB: silver nitrate = 100: 20 in molar ratio. Next, the mixed solution was applied onto a silicon wafer by spin coating (spin coating), and the solvent was evaporated to such an extent that it could be removed by heat treatment at 70 ° C. for 1 hour in a nitrogen atmosphere. Then, after heating up to 300 degreeC with the temperature increase rate of 4.6 degree / min and hold | maintaining for 90 minutes, the 14-micrometer-thick heat conductive film was prepared by standing to cool to room temperature. In addition, the grain size of the silver crystallites estimated from the spectral width of the diffraction peak attributed to metallic silver observed by wide-angle X-ray diffraction was 4.4 nm.

Comparative Example 6
Except that the mixing ratio of the N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 12%) and silver nitrate was BPDA / TFDB: silver nitrate = 100: 40 in molar ratio, The same operation as in Comparative Example 4 was performed to prepare a heat conductive film having a thickness of about 16 μm.

Comparative Example 7
Except that the mixing ratio of the N, N-dimethylacetamide solution of polyamic acid synthesized from BPDA and TFDB (solid content concentration 12%) and silver nitrate was BPDA / TFDB: silver nitrate = 100: 60 in molar ratio, The same operation as in Comparative Example 4 was performed to prepare a heat conductive film having a thickness of about 15 μm.

The thermal diffusivity of the heat conductive film obtained in the above Examples and Comparative Examples was measured. The measurement results are shown in Table 1. The thermal diffusivity is a physical property value obtained by dividing the thermal conductivity by the specific heat capacity and the density, and is a dominant factor of the thermal conductivity of the substance. The thermal diffusivity (m ² / s) in the film thickness direction at room temperature was measured by a temperature wave thermal analysis method (Eye Phase, Eye Phase Mobile 1u).

  From Table 1, it can be seen that the thermal conductive films of Example 1, Example 2, and Example 3 have a significant increase in thermal diffusivity as compared to films not containing silver (Comparative Example 1 and Comparative Example 2). It was.

  Moreover, the thermal conductive film of Example 1 and Example 2 has a large increase rate of a thermal diffusivity compared with the system (Comparative Examples 4, 5, 6, and 7) which does not form a phase-separated structure. This is because the heat transfer path is formed by the cylindrical or bicontinuous phase separation structure, and silver is selectively concentrated to the high metal affinity phase, resulting in efficient thermal conductivity even with a low silver content. This is because of the improvement.

  Moreover, the heat conductive film of Example 1, Example 2, and Example 3 has a high thermal diffusivity compared with the system (Comparative Example 3) which forms the phase-separation structure which has a sea-island structure. This is because, in a system having a phase separation structure of sea-island structure, a high metal affinity phase selectively containing silver is uniformly dispersed in the film, whereas a cylinder type or bicontinuous type phase separation structure is used. In systems with high metal affinity, the high metal affinity phase forms a heat transfer path, so that silver is selectively concentrated in the high metal affinity phase, resulting in efficient thermal conductivity even at the same silver content. This is because of the improvement.

In addition, since all the heat conductive film films shown in Examples 1 and 2 and Comparative Examples 1 to 6 were prepared by heat treatment at the maximum imidization temperature: 300 ° C. × 90 minutes, the heat resistance at 300 ° C. In fact, even after heating at 270 ° C for 5 minutes used in the solder reflow process, there was no change in properties such as weight, film thickness, thermal conductivity, and color tone. In particular, the heat conductive films shown in Example 2 and Comparative Example 4 have 5% weight loss temperatures (pyrolysis start temperatures) of 418 ° C. and 391 ° C., respectively, and have high heat resistance to withstand the solder reflow process. It is clear.

It is a cross-sectional perspective image by the optical microscope of the heat conductive film of Example 1. FIG. It is a cross-sectional image of the heat conductive film of Example 2 by a scanning electron microscope. It is a cross-sectional image of the heat conductive film of Example 3 by a scanning electron microscope. It is a cross-sectional image by the scanning electron microscope of the heat conductive film of the comparative example 3.

Explanation of symbols

1 High Metal Affinity Phase 2 of Example 1 Low Metal Affinity Phase 3 of Example 1 High Metal Affinity Phase 4 of Example 2 Low Metal Affinity Phase 5 of Example 2 High Metal Affinity Phase of Example 3 6 Low metal affinity phase 7 of Example 3 High metal affinity phase 8 of Comparative Example 3 Low metal affinity phase of Comparative Example 3

Claims (18)

A thermally conductive material having a structure in which thermally conductive fine particles are dispersed in a polymer matrix, wherein the polymer forming the polymer matrix is a polymer blend containing two or more polymer components, A heat conductive material characterized in that the polymer blend forms a cylindrical or bicontinuous phase separation structure, and the fine particles are unevenly distributed in one phase. 2. The heat conductive material according to claim 1, wherein the heat conductive fine particles are metallic fine particles. The heat conductive material of Claim 1 or 2 in which the said polymer blend contains 2 or more types of polymer components from which affinity with the said heat conductive microparticles | fine-particles differs. The heat conductive material in any one of Claims 1-3 in which the said polymer blend contains the high molecular component which has the heat resistance of 200 degreeC or more, or its precursor high molecular component. The polymer blend includes a polymer component containing a sulfur atom in a molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when forming a cylindrical or bicontinuous phase separation structure. The heat conductive material of any one of 1-4. The polymer blend includes a polymer component containing a disulfide bond in a molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. 5. The thermally conductive material according to 5. The polymer blend includes a polymer component containing a sulfide bond in a molecular structure as a main component of a phase in which thermally conductive fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. 5. The thermally conductive material according to 5. Dissolving a precursor of thermally conductive fine particles soluble in an organic solvent in a solution of a polymer blend containing two or more kinds of polymer components and capable of forming a cylindrical or co-continuous phase separation structure; and The method comprises forming a film by forming a solution of the polymer blend into a film, and then causing heat conductive fine particles or fine particle aggregates to be unevenly distributed in one polymer phase by heating and spontaneously depositing the polymer blend. The manufacturing method of the heat conductive material of any one of claim | item 1 -7. The precursor of the thermally conductive fine particles is selected from the group consisting of an inorganic metal compound, an organometallic compound, a complex of an inorganic metal compound and an organometallic compound, and a complex of an organometallic compound and an organometallic compound. The manufacturing method of the heat conductive material of 8. The method for producing a heat conductive material according to claim 8 or 9, wherein the polymer blend contains two or more kinds of polymer components having different affinity with the precursor of the heat conductive fine particles or the heat conductive fine particles. . The method for producing a thermally conductive material according to any one of claims 8 to 10, wherein the polymer blend contains a polymer component having heat resistance of 200 ° C or higher or a precursor polymer component thereof. The polymer blend includes a polymer component containing a sulfur atom in a molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. The manufacturing method of the heat conductive material of any one of these. 13. The polymer blend according to claim 12, comprising a polymer component containing a disulfide bond in a molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. The manufacturing method of the heat conductive material. The polymer blend includes a polymer component containing a sulfide bond in a molecular structure as a main component of a phase in which fine particles are unevenly distributed when a cylindrical or bicontinuous phase separation structure is formed. The manufacturing method of the heat conductive material. The heat conductive sheet produced using the heat conductive material of any one of Claims 1-7. The heat conductive sheet produced using the heat conductive material obtained by the manufacturing method of the heat conductive material of any one of Claims 8-14. The interlayer insulation film produced using the heat conductive material of any one of Claims 1-7. The interlayer insulation film produced using the heat conductive material obtained by the manufacturing method of the heat conductive material of any one of Claims 8-14.

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