JP2016204653A - Thermally conductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally conductive material having a markedly high thermal conductivity while reducing a content of a thermally conductive filler as much as possible.SOLUTION: A thermally conductive material comprises a polycarbonate resin and a polypropylene resin, and a thermally conductive filler, preferably a thermally conductive filler such as boron nitride.SELECTED DRAWING: None

Description

  The present invention relates to a heat conductive material, and more particularly, to a heat conductive material containing a polycarbonate resin and a polypropylene resin, and a heat conductive filler.

  In recent years, downsizing of mobile phones and personal computers has been promoted, and various problems have been pointed out. One of them is a problem of heat dissipation. This problem is caused by the fact that the thermal conductivity of a housing made of resin or a heat sink is generally very low compared to metal or ceramic.

  One technique for solving this problem is to increase the thermal conductivity of the filler composition. In this technique, the filler composition is made by combining the resin constituting the filler composition and the highly thermal conductive inorganic filler. The material is made to have a high thermal conductivity to make a heat conductive material.

  As such a heat conductive material, for example, Patent Document 1 discloses that two kinds of polymer phases such as nitrile butadiene rubber (NBR) and ethylene / propylene / diene rubber (EPDM) are dispersed to form a sea-island phase separation. A thermally conductive material having a structure and having a thermally conductive filler unevenly distributed in a polymer phase serving as a sea, Patent Document 2 discloses a thermoplastic resin excluding a thermoplastic polyester resin, a thermoplastic polyester resin, A high thermal conductivity thermoplastic resin composition containing a high thermal conductivity inorganic compound is described.

  Patent Document 3 contains at least three types of resins and a thermally conductive substance, one of which is a compatibilizer for another resin, and each resin constitutes a phase separation structure. However, a thermally conductive material in which a thermally conductive substance is selectively present in a resin as a compatibilizing agent is disclosed in Patent Document 4, which contains two types of resins and boron nitride. A thermally conductive material constituting the separation structure is described.

JP 2005-255867 A International Publication No. 2007/066671 JP 2013-194148 A JP 2013-194223 A

  However, the compositions described in Patent Documents 1 to 4 require a large amount of heat conductive material, but have insufficient heat conductivity, and mechanical properties such as heat resistance and elastic modulus of the resin composition are not sufficient. There was a problem.

  The present invention has been made in view of the current state of the prior art, and an object thereof is to provide a heat conductive material having particularly high heat conductivity while reducing the content of the heat conductive filler as much as possible. is there.

  As a result of intensive studies to solve the above problems, the present inventors have found that a heat conductive material containing a polycarbonate resin and a polypropylene resin and a heat conductive filler can solve the above problems. The present invention has been accomplished based on this finding.

That is, the gist of the present invention is as follows [1] to [7].
[1] A heat conductive material comprising a polycarbonate resin and a polypropylene resin, and a heat conductive filler.
[2] The heat conductive material according to [1], wherein the heat conductive filler is boron nitride.
[3] The heat conductive material according to [1] or [2], wherein the content of the polycarbonate-based resin is 10% by weight to 85% by weight with respect to the total amount of the heat conductive material.
[4] The heat conductive material according to any one of [1] to [3], wherein the content of the polypropylene resin is 5% by weight to 80% by weight with respect to the total amount of the heat conductive material.
[5] The heat conductive material according to any one of [1] to [4], wherein the content of the heat conductive filler is 10% by weight or more and 70% by weight or less with respect to the total amount of the heat conductive material.
[6] The heat conductive material according to any one of [1] to [5], wherein the average particle size of the heat conductive filler is 1 μm or more and 50 μm or less.
[7] The heat conductive material according to any one of [1] to [6], wherein the polycarbonate resin includes at least a structural unit derived from a dihydroxy compound represented by the following formula (1).

  The heat conductive material of the present invention is excellent in mechanical properties such as heat resistance and elastic modulus, and has particularly high heat conductivity.

  Hereinafter, the present invention will be described in detail with reference to embodiments, examples, etc., but the present invention is not limited to the following embodiments, examples, etc., and can be arbitrarily set within the scope of the present invention. Can be changed and implemented.

  The heat conductive material of the present invention is characterized by containing a polycarbonate resin and a polypropylene resin, and a heat conductive filler.

  Although the details of the reason why the heat conductive material of the present invention has a particularly high heat conductivity compared to a heat conductive material containing a heat conductive filler in polypropylene resin or polycarbonate resin is not clear, it constitutes the sea It is considered that the heat conductive filler is unevenly distributed in the phase, and thus has higher heat conductivity than the resin in which the heat conductive filler is uniformly dispersed.

<Polycarbonate resin>
There is no restriction | limiting in particular in the kind of polycarbonate-type resin used by this invention. One type of polycarbonate resin may be used, or two or more types may be used in any combination and ratio.

  The polycarbonate resin is a polymer having a basic structure having a carbonic acid bond, represented by a general formula:-[-O-X-O-C (= O)-]-. In the formula, X is generally a hydrocarbon group, but may have a heteroatom for imparting various properties.

The polycarbonate-based resin can be classified into an aromatic polycarbonate resin in which the carbon directly bonded to the carbonic acid bond is an aromatic carbon and an aliphatic polycarbonate resin in which the carbon is an aliphatic carbon, either of which can be used. Among these, an aliphatic polycarbonate resin is preferable from the viewpoint of weather resistance and compatibility with a polypropylene resin, and an aliphatic polycarbonate resin containing an alicyclic dihydroxy compound is more preferable.
An aromatic polycarbonate resin is preferred from the viewpoints of heat resistance, mechanical properties, electrical characteristics, and the like.

  Although there is no restriction | limiting in the specific kind of polycarbonate-type resin, For example, the polycarbonate polymer obtained by making a dihydroxy compound, cyclic ethers, etc., such as an aromatic dihydroxy compound and an aliphatic dihydroxy compound, and a carbonate precursor react. Can be mentioned. At this time, in addition to the dihydroxy compound and the carbonate precursor, a polyhydroxy compound or the like may be reacted. Alternatively, a method of reacting with cyclic ether using carbon dioxide as a carbonate precursor may be used. The polycarbonate polymer may be linear or branched. Further, the polycarbonate polymer may be a homopolymer composed of one type of repeating unit or a copolymer having two or more types of repeating units. At this time, the copolymer can be selected from various copolymerization forms such as a random copolymer and a block copolymer. In general, such a polycarbonate polymer is a thermoplastic resin.

  As an aromatic dihydroxy compound used as the raw material of aromatic polycarbonate resin, the following compounds are mentioned, for example.

  1,2-dihydroxybenzene, 1,2-benzenedimethanol, 1,3-dihydroxybenzene (ie, resorcinol), 1,3-benzenedimethanol, 1,4-dihydroxybenzene, 1,4-benzenedimethanol, Dihydroxybenzenes such as 1,4-benzenediethanol, 1,3-bis (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxy) benzene; 4,4′-biphenyldimethanol, 4, Dihydroxybiphenyls such as 4′-biphenyldiethanol, 1,4-bis (2-hydroxyethoxy) biphenyl, 2,5-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl; 2,2 '-Dihydroxy-1,1'-binaphthyl, 1,2-dihydro Sinaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-bis (hydroxymethyl) naphthalene, 1,6-dihydroxynaphthalene, 1,6-bis (hydroxyethoxy) naphthalene, 2,6- Dihydroxynaphthalenes such as dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene; bisphenols such as bisphenol A bis (2-hydroxyethyl) ether and bisphenol S bis (2-hydroxyethyl) ether.

  2,2′-dihydroxydiphenyl ether, 3,3′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, 1,4-bis (3-hydroxyphenoxy) Dihydroxy diaryl ethers such as benzene and 1,3-bis (4-hydroxyphenoxy) benzene;

2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A), 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2 , 2-bis (3-methoxy-4-hydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (3-methoxy-4-hydroxyphenyl) propane, 1,1-bis (3-tert-butyl) -4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane, 2- (4-hydroxy Phenyl) -2- (3-cyclohexyl-4-hydroxyphenyl) propane, α, α′-bis (4-hydroxyphenyl)- , 4-diisopropylbenzene, 1,3-bis [2- (4-hydroxyphenyl) -2-propyl] benzene, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) cyclohexylmethane, bis (4- Hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) (4-propenylphenyl) methane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) naphthylmethane, 1,1-bis (4-hydroxyphenyl) ) Ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-naphthylethane, 1,1-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis ( 4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) octane, 2,2- Bis (4-hydroxyphenyl) octane, 1,1-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) hexane, 4,4-bis (4-hydroxyphenyl) heptane, 2, Bis (hydroxyaryl) alkanes such as 2-bis (4-hydroxyphenyl) nonane, 1,1-bis (4-hydroxyphenyl) decane and 1,1-bis (4-hydroxyphenyl) dodecane.

  1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethylcyclohexane, 1,1- Bis (4-hydroxyphenyl) -3,4-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3 5-trimethylcyclohexane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3-propyl-5 Methylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3-tert-butyl-cyclohexane, 1,1-biphenyl (4-hydroxyphenyl) -3-tert-butyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) -3-phenylcyclohexane, 1,1-bis (4-hydroxyphenyl) -4-phenylcyclohexane, etc. Bis (hydroxyaryl) cycloalkanes.

  Cardo-structure-containing bisphenols such as 9,9-bis (4-hydroxyphenyl) fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene.

  Dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide.

  Dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide.

  Dihydroxy diaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.

Among these, bis (hydroxyaryl) alkanes are preferable, and bis (4-hydroxyphenyl) alkanes are preferable, and 2,2-bis (4-hydroxyphenyl) propane (ie, from the viewpoint of impact resistance and heat resistance). Bisphenol A) is preferred.
In addition, 1 type may be used for an aromatic dihydroxy compound and it may use 2 or more types together by arbitrary combinations and a ratio.

  Moreover, as an aliphatic dihydroxy compound and cyclic ether used as the raw material of aliphatic polycarbonate resin, the following compounds are mentioned, for example. In the present invention, the aliphatic dihydroxy compound is a dihydroxy compound having a saturated hydrocarbon group, and does not include cyclic ethers in which a part of the cyclic hydrocarbon is substituted with a hetero atom.

  Aliphatic dihydroxy compounds include ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-methyl-2- Propylpropane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, decane-1,10-diol, 2,2′-oxydiethanol (ie , Diethylene glycol), alkanediols such as triethylene glycol spiroglycol; cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, 1,4-cyclohexanedimethanol, 4- (2-hydroxyethyl) cyclohexanol, 2,2,4,4-tetramethyl-cycl Cycloalkane diols such as butane-1,3-diol.

  As cyclic ethers, 1,2-epoxyethane (ie, ethylene oxide), 1,2-epoxypropane (ie, propylene oxide), 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,4-epoxy Cyclohexane, 1-methyl-1,2-epoxycyclohexane, 2,3-epoxynorbornane, 1,3-epoxypropane; isosorbide, isomannide, isoidet (stereoisomer of the compound represented by the following general formula (1)) Can be mentioned.

  In addition, 1 type may be used for an aliphatic dihydroxy compound and cyclic ether, and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, you may use together with an aromatic dihydroxy compound.

  The polycarbonate resin used in the present invention includes at least a structural unit derived from the dihydroxy compound represented by the above general formula (1) (hereinafter sometimes referred to as “dihydroxy compound (1)”) in a part of the structure. It is preferable from the viewpoint of improving mechanical properties.

  The ratio of the structural unit derived from the dihydroxy compound (1) to the structural unit derived from all the dihydroxy compounds constituting the polycarbonate-based resin is usually 20 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more. Usually, it is 90 mol% or less, preferably 85 mol% or less, more preferably 80 mol% or less.

  When the proportion of the structural unit derived from the dihydroxy compound (1) is too large, the weather resistance of the molded product obtained by molding the heat conductive material of the present invention tends to deteriorate. However, this cracking can also be prevented by including a light-resistant stabilizer. On the other hand, if the proportion of the structural unit derived from the dihydroxy compound (1) is too small, the heat resistance of the resulting molded product may be lowered.

  As a carbonate precursor used as the raw material of polycarbonate-type resin, a carbonyl halide, carbonate ester, etc. are mentioned, for example. In addition, 1 type may be used for a carbonate precursor and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the carbonyl halide include phosgene; haloformates such as a bischloroformate of a dihydroxy compound and a monochloroformate of a dihydroxy compound.

  Examples of the carbonate ester include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; dihydroxy compounds such as biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds, and cyclic carbonates. And the like.

  In the present invention, the method for producing a polycarbonate-based resin is not particularly limited, and the above raw materials are used as appropriate, for example, an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, Any method such as a solid phase transesterification method of a prepolymer may be employed.

  In the present invention, the melt flow rate (MFR) of the polycarbonate-based resin is not particularly limited, but is usually 5 g / 10 min or more, preferably 10 g / 10 min or more, more preferably 15 g / 10 min, still more preferably 50 g / 10 min. Moreover, it is 200 g / 10min or less normally, Preferably it is 150 g / 10min or less, More preferably, it is 130 g / 10min or less, More preferably, it is 120 g / 10min or less. When the melt flow rate (MFR) is within the above range, the injection moldability is good. The melt flow rate (MFR) is a value measured according to ISO 1133.

  The molecular weight of the polycarbonate resin is not particularly limited, but the viscosity average molecular weight (Mv) converted from the solution viscosity is usually 10,000 or more, preferably 16,000 or more, more preferably 17,000 or more, and usually It is 40,000 or less, preferably 30,000 or less, more preferably 24,000 or less. By setting the viscosity average molecular weight to the lower limit value or more, the mechanical strength of the heat conductive material of the present invention can be further improved, which is more preferable when used for applications requiring high mechanical strength. On the other hand, by setting the viscosity average molecular weight to the upper limit value or less, it is possible to suppress and improve the fluidity reduction of the heat conductive material of the present invention, and it is possible to easily perform the thin-wall molding process by improving the molding processability.

  The viscosity average molecular weight can be adjusted by mixing two or more different polycarbonate resins. In this case, a polycarbonate resin having a viscosity average molecular weight outside the above preferred range may be mixed.

The viscosity average molecular weight (Mv) is obtained by using methylene chloride as a solvent and obtaining an intrinsic viscosity [η] (unit: dl / g) at a temperature of 20 ° C. using an Ubbelohde viscometer. , Η = 1.23 × 10 ⁻⁴ Mv0.83. The intrinsic viscosity [η] is a value calculated from the following equation by measuring the specific viscosity [ηsp] at each solution concentration [C] (g / dl).

  The terminal hydroxyl group concentration of the polycarbonate resin is not particularly limited, but is usually 1,000 ppm or less, preferably 800 ppm or less, more preferably 600 ppm or less. Thereby, the residence heat stability and color tone of a polycarbonate-type resin can be improved more. In addition, the lower limit is usually 10 ppm or more, preferably 30 ppm or more, more preferably 40 ppm or more, particularly for polycarbonate resins produced by the melt transesterification method. Thereby, the fall of molecular weight can be suppressed and the mechanical characteristic of polycarbonate-type resin can be improved more.

  In addition, the unit of a terminal hydroxyl group density | concentration displays the mass of a terminal hydroxyl group with respect to the mass of polycarbonate-type resin in ppm. The measuring method is colorimetric determination (Macromol. Chem. 88, 215 (1965)) by the titanium tetrachloride / acetic acid method.

  The polycarbonate resin may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. Furthermore, the polycarbonate oligomer contained is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer). Thereby, the external appearance improvement and fluidity | liquidity improvement of the molded object of a heat conductive material can be aimed at.

  These polycarbonate resins can be obtained as commercial products. Examples of aromatic polycarbonates include Iupilon (registered trademark) series, Novalex (registered trademark) series, Zanta (registered trademark) series manufactured by Mitsubishi Engineering Plastics, Inc., Panlite (registered commercial law) manufactured by Teijin Limited. Series etc. are mentioned. Moreover, as a polycarbonate containing at least a structural unit derived from the dihydroxy compound represented by the general formula (1) in a part of the structure, Durabio (registered trademark) series manufactured by Mitsubishi Chemical Corporation may be mentioned. Applicable products can be appropriately selected from these and used.

<Polypropylene resin>
There are no particular restrictions on the type of polypropylene resin used in the present invention. For example, propylene homopolymers, propylene / ethylene copolymers (including block copolymers and random copolymers) and propylene / α-olefin copolymers are used. One or more crystalline polypropylenes selected from the group consisting of polymers (including block copolymers and random copolymers), or homopolymers or copolymers of α-olefins other than the crystalline polypropylene and propylene; Is preferred.

  Examples of the copolymer include an impact-resistant propylene-based block copolymer, for example, a propylene / ethylene block copolymer. Two or more of these polypropylene resins may be used in combination. When particularly high impact resistance is required, it is preferable to use a propylene-based block copolymer, and when particularly high rigidity is required, it is preferable to use a propylene homopolymer.

  Further, the group in which the polypropylene resin is composed of a propylene / ethylene copolymer (including a block copolymer and a random copolymer) and a propylene / α-olefin copolymer (including a block copolymer and a random copolymer). In the case of one or more kinds of copolymers selected from the above, examples of the copolymer component include ethylene; α-olefins having 4 to 20 carbon atoms, such as butene-1, hexene-1, and octene-1.

When the polypropylene resin is a copolymer of propylene and a vinyl compound, examples of the vinyl compound include styrene, vinylcyclopentene, vinylcyclohexane, and the like.

  When the polypropylene resin is a copolymer of propylene and vinyl ester, examples of the vinyl ester include vinyl acetate. In the case of a copolymer of propylene and an unsaturated organic acid or derivative thereof, examples of the unsaturated organic acid or derivative thereof include maleic anhydride. The α-olefin and vinyl compound copolymerized with propylene may be used singly or in combination of two or more. Of these, ethylene and butene-1 are preferred.

  In the present invention, the method for producing a polypropylene-based resin is not particularly limited, and a known method, for example, slurry polymerization, gas phase polymerization or high-order regularity catalyst such as a Ziegler-based catalyst and a metallocene-based catalyst is used. A polypropylene resin can be produced by liquid phase bulk polymerization. In addition, as a polymerization method, a conventionally known method can be used, and either batch polymerization or continuous polymerization can be employed.

  In the present invention, the melt flow rate (MFR) of the polypropylene resin is not particularly limited, but is usually 0.5 g / 10 min or more, preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, Usually, it is 100 g / 10 minutes or less, preferably 80 g / 10 minutes or less, more preferably 60 g / 10 minutes, still more preferably 40 g / 10 minutes or less. When the melt flow rate (MFR) is within the above range, the injection moldability is good. The melt flow rate (MFR) is a value measured according to JIS K7210 (.

  These polypropylene resins can be obtained as commercial products. Specific examples include Novatec (registered trademark) PP series, Wintec (registered trademark) series manufactured by Nippon Polypro Co., Ltd., Prime Polypro (registered trademark) manufactured by Prime Polymer Co., Ltd., and the like. Applicable products can be appropriately selected from these and used.

<Thermal conductive filler>
In the present invention, the heat conductive filler is not particularly limited, but an inorganic material having high heat conductivity is preferable. Specific examples include boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, and the like from the viewpoint of compatibility with the resin composition. Boron nitride, aluminum nitride, and silicon nitride are preferable, and boron nitride is more preferable.
In addition, when the thermally conductive filler is conductive, the electrical resistance of the thermally conductive filler tends to be difficult to use in applications that require insulation (for example, a member or casing that contacts an electronic component). The rate is preferably 10 ¹³ Ω · m or more, more preferably 10 ¹⁴ Ω · m or more.
These heat conductive fillers may be used alone or in combination of two or more in any combination and ratio.

  The average particle size of the heat conductive filler is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, particularly preferably 5 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, particularly preferably 15 μm. It is as follows.

In the present invention, the heat conductive filler may have any shape, but is preferably in the form of particles (that is, heat conductive particles), and particularly preferably scaly particles.
By using a thermally conductive filler having an average particle diameter as described above, preferably boron nitride, good thermal conductivity and good fluidity can be obtained.

A commercial item can also be used for a heat conductive filler, and what was manufactured in accordance with the well-known method can also be used. In addition, when a heat conductive filler, for example, boron nitride is produced according to a known method, immediately after synthesis, the powder may aggregate and may not satisfy the above particle size range. Therefore, it is preferable to pulverize and use boron nitride so as to satisfy the above particle size range.

A method for pulverizing the heat conductive filler, for example, boron nitride, is not particularly limited, and a conventionally known pulverization method such as jet mixing or the like can be applied together with a pulverizing medium such as zirconia beads.
In addition, a thermally conductive filler such as boron nitride may be appropriately subjected to a surface treatment in order to improve dispersibility in the thermally conductive material.

  The average particle diameter of the heat conductive filler such as boron nitride can be measured by, for example, dispersing it in a suitable solvent and using a laser diffraction / scattering particle size distribution analyzer LA-920 manufactured by Horiba. . The average particle diameter of boron nitride can be determined from the obtained particle size distribution. The average particle diameter referred to here is a volume-based average particle diameter. Similarly, the average particle diameter of boron nitride in the heat conductive material can be measured by dispersing it in a suitable solvent (dissolving the resin component in the solvent) and using the same apparatus as described above.

<Heat conductive material>
The heat conductive material of this invention is a resin composition containing said polycarbonate-type resin and polypropylene-type resin, and a heat conductive filler. The heat conductive material of the present invention may further contain other components as necessary.

  In the heat conductive material of the present invention, the content of the polycarbonate-based resin is usually 10% by weight or more, preferably 15% by weight or more, more preferably 20% by weight or more based on the total amount of the heat conductive material. Further, it is usually 85% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less. When the content of the polycarbonate-based resin is in the above range, it is preferable from the viewpoint that a heat conductive material excellent in heat conductivity can be produced and that the heat resistance and mechanical properties of the obtained heat conductive material are improved. Moreover, when there is too little content of a polycarbonate-type resin, there exists a tendency which leads to a heat resistant fall, and when too much, there exists a tendency for the contact between boron nitrides to decrease and to lead to a heat conductive fall.

  The content of the polypropylene resin is usually 5% by weight or more, preferably 10% by weight or more, more preferably 12% by weight or more, based on the total amount of the heat conductive material, relative to the total amount of the heat conductive material. Moreover, it is 80 weight% or less normally, Preferably it is 50 weight% or less, More preferably, it is 30 weight% or less. When the content of the polypropylene resin is in the above range, it is preferable from the viewpoint that a heat conductive material excellent in heat conductivity can be produced and that the heat resistance and mechanical properties of the obtained heat conductive material are improved. Moreover, when there is too little content of a polypropylene-type resin, there exists a tendency for the contact between boron nitrides to decrease and it will lead to a heat conductive fall, and when too much, there exists a tendency for heat resistance to fall.

  The content ratio of the polycarbonate resin and the polypropylene resin is not particularly limited, but a ratio in which these two types of resins can be dispersed to form a sea-island phase separation structure is preferable. The ratio obtained is more preferred. Specifically, the content of the polycarbonate resin is preferably 50 parts by weight or more, more preferably 80 parts by weight or more, particularly preferably 100 parts by weight or more, with respect to 100 parts by weight of the polypropylene resin. The amount is preferably 500 parts by weight or less, more preferably 400 parts by weight or less, and particularly preferably 300 parts by weight or less. By setting the content ratio of the resin within the above range, a preferable phase structure is obtained and moldability is improved.

Furthermore, the content of the heat conductive filler is preferably 10% by weight or more, more preferably 30% by weight or more, particularly preferably 40% by weight or more, and preferably 70% by weight, based on the total amount of the heat conductive material. % Or less, more preferably 65% by weight or less, particularly preferably 60% by weight or less. By making content of a heat conductive filler into this range, the heat conductive material provided with high heat conductivity and favorable moldability can be obtained.

In the present invention, the phase structure of the thermally conductive material is not particularly limited, but a phase separation structure of sea-island, a phase structure in which two types of resins are continuous (co-continuous structure), and a phase structure in which two types of resins are continuous ( And a sea-island phase separation structure. Among them, the heat-conductive filler in the heat-conducting material is likely to be localized, and from the viewpoint of improving the heat conductivity of the sea-island. Those having a phase separation structure are preferred.
In addition, the phase structure of a heat conductive material can be measured by the method as described in the Example mentioned later.

When the phase structure of the heat conductive material of the present invention is a sea-island phase separation structure, the content of the layer constituting the island is usually 5 when the content of the phase constituting the sea is 1 on a weight basis. Hereinafter, it is preferably 3 or less, more preferably 2.5 or less, particularly preferably 2 or less, while the lower limit is usually 0.01 or more, preferably 0.1 or more, more preferably 0.2 or more.
When the ratio of the layers constituting the sea-island structure is within the above range, the thermally conductive filler is unevenly distributed in the layers constituting the sea, and a thermally conductive material having higher thermal conductivity tends to be obtained.

The thermal conductivity of the heat conductive material of the present invention is preferably 1.3 W / m · K or more, more preferably 1.5 W / m · K or more, and particularly preferably 1.8 W / m · K or more. An upper limit is not specifically limited, It is below the heat conductivity in a heat conductive filler single-piece | unit.
The thermal conductivity is obtained by measuring the thermal diffusivity and specific gravity of the thermal conductive material, measuring the specific heat, and multiplying these three measured values by the method described in the examples described later. be able to.

  The heat conductive material of the present invention having the above-mentioned characteristics includes the above polycarbonate resin, polypropylene resin, and heat conductive filler, and if necessary, materials containing other components are mixed simultaneously and uniformly by stirring and kneading. Can be manufactured. Specifically, for example, the material may be kneaded by heating as necessary using a general kneading apparatus such as a mixer, a kneader, a single-screw or twin-screw kneader.

The temperature of the cylinder at this time is usually 180 ° C. or higher, preferably 200 ° C. or higher, more preferably 210 ° C. or higher, while the upper limit is usually 300 ° C. or lower, preferably 280 ° C. or lower.
Further, the rotational speed of the kneading apparatus is usually 10 rpm or more, preferably 50 rpm or more, more preferably 100 rpm or more, while the upper limit is usually 400 rpm or less, preferably 300 rpm or less.

  In the thermally conductive material of the present invention, other components that can be included as necessary include, for example, a functional resin imparted with functionality to the above resin such as a liquid crystalline epoxy resin, aluminum nitride, silicon nitride, Nitride particles such as fibrous boron nitride, insulating metal oxides such as alumina, fibrous alumina, zinc oxide, magnesium oxide, beryllium oxide, and titanium oxide, insulating carbon components such as diamond and fullerene, compatibilizer, resin Examples include a curing agent, a resin curing accelerator, a viscosity modifier, a dispersion stabilizer, and a solvent.

In addition to the above exemplified nitride particles and insulating metal oxides, silane coupling improves the interfacial bond strength between inorganic fillers such as aluminum hydroxide and magnesium hydroxide, and inorganic filler and matrix resin. And surface treatment agents such as agents, reducing agents and the like.

  The resin curing agent is appropriately selected according to the type of resin used. Examples of the acid anhydride curing agent include tetrahydrophthalic acid anhydride, methyltetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, and benzophenone tetracarboxylic acid anhydride. Examples of the amine curing agent include aliphatic polyamines such as ethylenediamine, diethylenetriamine, and triethylenetetramine, aromatic polyamines such as diaminodiphenylsulfone, diaminodiphenylmethane, diaminodiphenyl ether, and m-phenylenediamine, and dicyandiamide.

  The resin curing accelerator is appropriately selected according to the type of resin used and the resin curing agent. For example, as the resin curing accelerator for the acid anhydride curing agent, for example, boron trifluoride monoethylamine, 2-ethyl-4-methylimidazole, 1-isobutyl-2-methylimidazole, 2-phenyl-4-methylimidazole Is mentioned.

The solvent can be used from the viewpoint of reducing the viscosity of the heat conductive material. As the solvent, a solvent that dissolves the resin from among known solvents is used. Examples of such solvents include methyl ethyl ketone, acetone, cyclohexanone, toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, phenol, and hexafluoroisopropanol.
There is no restriction | limiting in particular in content of these other components, What is necessary is just content in the range which does not impair the effect of this invention.

  The thermally conductive material of the present invention can be further molded and used as a molded body. The molding can be appropriately performed according to the state of the thermally conductive material and the type of resin by using a method generally used for molding the thermally conductive material.

  For example, the heat conductive material having plasticity or fluidity can be molded by curing the heat conductive material in a desired shape, for example, in a state of being accommodated in a mold. In the production of such a molded body, injection molding, injection compression molding, extrusion molding, and compression molding can be used. Molding can be performed under conditions of a temperature equal to or higher than the melting temperature of the resin and a predetermined molding speed and pressure. The molded body can also be obtained by cutting a cured product of a heat conductive material into a desired shape.

  When the heat conductive material of the present invention is molded by injection molding, the mold temperature at the time of injection molding is usually 180 ° C. or higher, preferably 200 ° C. or higher, more preferably 210 ° C. or higher, while the upper limit is usually 300 ° C. or lower, preferably 280 ° C. or lower. It is preferable that the mold temperature at the time of injection molding is in the above range from the viewpoint of maintaining the resin phase separation structure in the molded body in the predetermined state of the present invention.

<Applications of heat conductive materials>
The use of the heat conductive material of the present invention is not particularly limited. For example, a composite heat conductive sheet composed of a heat sink such as a heat radiating fin or a heat radiating plate and a thermoplastic resin having flexibility to be mounted between the semiconductor package and the wiring board. , Composite heat conductive materials with polyimide and other resins for use in environments where high heat resistance is required, or composite materials with thermoplastic resins for HEV and motor parts for electric vehicles, semiconductor sealing materials And interlayer filling compositions such as underfill, and interlayer filling compositions of three-dimensional integrated circuits.

By using the heat conductive material of the present invention, not only the moldability can be improved, but also high heat conductivity can be maintained. Furthermore, the heat conductive material of the present invention has high heat resistance and little thermal deformation even when used under high temperature conditions for a long time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. The various conditions, composition ratios, and evaluation result values in the following examples have meanings as preferred values of the upper limit or lower limit in the embodiment of the present invention, and the preferred range is the upper limit or lower limit described above. It may be a range defined by a combination of a value and a value in the following example or a value between examples.

<Raw material and evaluation method>
(1) Raw material (1-1) Polycarbonate resin / polycarbonate resin A (PC _A ): “Iupilon HL-7001” manufactured by Mitsubishi Engineering Plastics Co., Ltd. (MFR (ISO 1133 compliant, 300 ° C., load 1.20 kgf) = 113g / 10min)
Polycarbonate resin B (PC _B ): “Durabio D7340” manufactured by Mitsubishi Chemical Corporation (MFR (ISO 1133 compliant, 230 ° C., load 2.16 kgf) = 11 g / 10 min)

(1-2) Polypropylene resin / polypropylene resin (PP): “NOVATEC PP MA1B” manufactured by Nippon Polypro Co., Ltd. (MFR (according to JIS K7210, 230 ° C., load 2.16 kgf) = 21 g / 10 min)

(1-3) Thermally conductive particles, boron nitride A (BN _A ): “PT120” manufactured by MOMENTIVE
(Average particle size 8-14 μm)
Boron nitride B (BN _B ): “GP” (average particle size: 7 to 10 μm) manufactured by Denka Co., Ltd.

(2) Various evaluation methods (2-1) Measurement of thermal conductivity of thermal conductive material Measure thermal diffusivity, specific gravity and specific heat with the following devices, and multiply these three measured values to conduct heat. The rate was determined.

-Evaluation of thermal diffusivity Using a vacuum melting press (manufactured by Imoto Seisakusho Co., Ltd.), a disk-shaped sample having a thickness of 500 μm and a diameter of 25 mm was produced under the conditions of a press temperature of 220 ° C. and a press pressure of 8 MPa. The thermal diffusivity at 25 degreeC was measured by ai-Phase Mobile (made by Eye Phase Co., Ltd.) using the produced disk-shaped sample.

-Evaluation of specific gravity Using a specific gravity measurement kit (model: AD-1653, manufactured by A & D Co., Ltd.), the specific gravity of the thermally conductive material in ethanol at 25 ° C was measured.

・ Evaluation of specific heat Using a temperature modulation differential scanning calorimetry (model: Q-200, manufactured by TA Instrument), measurement was carried out under a temperature range of 10-50 ° C., modulation ± 1 ° C., 3 ° C./min. The specific heat at 25 ° C. of the thermally conductive material was read from the obtained results.

(2-2) Phase structure of heat conductive material and evaluation of dispersibility of BN / SEM observation of cross section of heat conductive material by scanning electron microscope (SEM) Cooling and breaking the kneaded material with liquid nitrogen, then dichloromethane Then, the polycarbonate-based resin was etched and platinum was deposited on the observation surface to prepare a sample for cross-sectional observation. Cross-sectional observation was performed using a scanning electron microscope (model: TM-1000, manufactured by Hitachi High-Technologies Corporation) to evaluate the phase structure.

-Observation of internal structure of heat conductive material by transmission electron microscope (TEM) Observation of the internal structure of heat conductive material was performed using a transmission electron microscope (model: JEM-1230 TE).
M, manufactured by JEOL Ltd.), and the dispersibility (BN dispersion) of boron nitride was evaluated.

<Example 1>
A resin composition is prepared by mixing 30 parts by weight of a polycarbonate resin A, 20 parts by weight of a polypropylene resin, and 50 parts by weight of boron nitride A, using a biaxial kneader (model: Labo Plast Mill μ4C15, manufactured by Toyo Seiki Seisakusho Co., Ltd.). (Thermal conductive material) was manufactured. The kneading conditions were a cylinder set temperature of 220 ° C., a rotation speed of 60 rpm, and a kneading time of 200 seconds. The obtained resin composition (thermally conductive material) was evaluated on which resin phase contained more heat conductivity, phase structure, and boron nitride. The results are shown in Table 1.

<Example 2, Comparative Examples 1-2>
A resin composition (thermally conductive material) was produced under the same conditions as in Example 1 except that the mixing ratio of the raw materials was changed to the ratio shown in Table 1. Various evaluation results are shown in Table 1.
<Example 3, Comparative Example 3>
A resin composition (thermally conductive material) was produced under the same conditions as in Example 1 except that the mixing ratio of the raw materials was set to the ratio shown in Table 1 and the kneading time was 180 seconds. Various evaluation results are shown in Table 1.
<Example 4, comparative example 4>
A resin composition (thermally conductive material) was produced under the same conditions as in Example 1, except that the mixing ratio of the raw materials was the ratio shown in Table 1, the cylinder set temperature was 240 ° C., and the kneading time was 180 seconds. . Various evaluation results are shown in Table 1.

  From Examples and Comparative Examples, the thermal conductivity of a resin composition (thermally conductive material) made of polycarbonate resin, polypropylene resin, and boron nitride is greatly improved compared to the case where boron nitride is added to the resin alone. I understand that.

Claims (7)

  A heat conductive material comprising a polycarbonate resin and a polypropylene resin, and a heat conductive filler.   The thermally conductive material according to claim 1, wherein the thermally conductive filler is boron nitride.   The heat conductive material of Claim 1 or 2 whose content of polycarbonate-type resin is 10 to 85 weight% with respect to the whole quantity of a heat conductive material.   The heat conductive material of any one of Claims 1-3 whose content of a polypropylene resin is 5 to 80 weight% with respect to the whole quantity of a heat conductive material.   The heat conductive material of any one of Claims 1-4 whose content of a heat conductive filler is 10 to 70 weight% with respect to the heat conductive material whole quantity.   The heat conductive material of any one of Claims 1-5 whose average particle diameter of a heat conductive filler is 1 micrometer or more and 50 micrometers or less. The heat conductive material of any one of Claims 1-6 in which a polycarbonate-type resin contains the structural unit derived from the dihydroxy compound represented by following formula (1) at least.