JP4597899B2 - Heat-dissipating gel composition and method for producing the same - Google Patents

Description

  The present invention relates to a gel composition containing an ionic liquid used for heat dissipation and a gelling agent, and a method for producing the same.

  In recent years, the performance of electronic devices such as personal computers, mobile phones, and PDAs has improved significantly, which is due to the significant improvement in CPU performance. Along with such improvement in CPU performance, the amount of heat generated by the CPU also increases remarkably, and how to dissipate heat in electronic devices is an important issue. Such an increase in the amount of generated heat is a serious problem not only in the CPU but also in many fields such as memories, various electronic components, and batteries.

  As heat countermeasures, there are methods such as air cooling with fans, heat pipes, water cooling with water, etc., but these all require new heat dissipation devices, not only increase the weight of the equipment, but also noise and There is a disadvantage that it causes an increase in the amount of electricity used. The most common method for heat dissipation of the CPU is a method using a heat sink. The purpose of this is to increase the cooling efficiency by diffusing the generated heat as quickly as possible to a large area. The most important point in such a heat dissipation system is how to connect a heat source such as a CPU and a heat sink with a reduced thermal resistance. Since the thermal resistance is remarkably increased when an air layer is present at the contact interface, a grease-like, rubber-like or gel-like composition is used for the purpose of realizing complete adhesion. A product group called a heat radiation pad, a heat radiation oil compound, or a heat radiation grease used for this purpose is applied to the connection interface or sandwiched between the connection interfaces.

  Examples of these include many examples such as Three Bond Co., Ltd .: Heat Dissipation Silicon Gel Sheet, Geltech Co., Ltd .: Lambda GEL Paste, R.E. In order to increase heat conduction, these products are made of organic materials with flexibility, such as greases, rubbers, gels and other organic materials with flexibility, inorganic and ceramic fillers and metal fillers with excellent thermal conductivity. For example, silicone organic materials and acrylic organic materials are used exclusively. For example, Patent Documents 1 to 4 can be exemplified as techniques related to these heat radiation sheets. However, the thermal conductivity of these products is about 3.0 to 0.5 W / m · K, which is much smaller than, for example, 403 W / m · K for copper and 236 W / m · K for aluminum. Improvement of thermal conductivity has been desired.

  Although improvement and selection of fillers to be added are important for improving heat conduction, improving the heat conductivity of the organic material itself as a base material is an important issue. Furthermore, it is desirable that as much heat conductive filler as possible can be added to improve the thermal conductivity, but if the amount added is increased, the flexibility and mechanical strength of the sheet are lost. Therefore, it is also important to devise so that the flexibility of the sheet is not lost even if a large amount of filler is added.

On the other hand, the ionic liquid which is the main component of the present invention is formed from a cation and an anion, which is a liquid at room temperature (for example, at 10 ° C. to 30 ° C.) and is also called a room temperature molten salt. It is. Such an ionic liquid has high ion conductivity and is expected to be applied as an electrolyte for batteries and the like. Furthermore, in the electrolyte in a liquid state, since there is a problem of leakage of the electrolyte from a battery or the like, it is proposed to gel the ionic liquid in order to form a solid electrolyte containing the ionic liquid (for example, , See Patent Literature 5 to Patent Literature 8). In addition, the conductive gel-like material is expected to be used as a bioelectrode and a sensor in addition to the use as a solid electrolyte. However, there is no known example in which such a gelled ionic liquid is used for heat dissipation.
Japanese Patent Publication 3712943 Japanese Patent Publication No. 2882972 JP 2002-84083 A Japanese Patent Laid-Open No. 2001-110961 JP 2002-003478 A JP 2003-257240 A JP 2003-303630 A JP 2004-098199 A

  An object of this invention is to provide the highly heat conductive gel-like composition applicable as a heat dissipation use, and its manufacturing method.

  The present invention has found that a gel composition prepared using an ionic liquid can exhibit excellent heat conduction, and moreover without losing its flexibility as compared with conventional gel compositions and rubber compositions. It was discovered that a heat radiating sheet having excellent heat conduction characteristics can be realized as a result.

  Accordingly, a first aspect of the present invention is a heat-dissipating gel composition characterized by being obtained by gelling an ionic liquid containing at least an ionic liquid and a gelling agent. The obtained gel has thermal conductivity superior to known gels obtained by other methods, and is preferable as a gel for heat dissipation. In addition, the ionic liquid has a very low vapor pressure and practically hardly evaporates, so that the obtained gel-like composition is extremely stable, so that it is extremely preferable as a gel for heat dissipation.

Moreover, this invention contains an ionic liquid and a gelling agent, The mass concentration of the said gelling agent with respect to the said ionic liquid can be 2 wt% or more and 50 wt% or less.
Furthermore, this invention can be made into the gel composition for thermal radiation by which 20-1000 wt% of heat conductive inorganic filler was mixed with respect to the said gel-like composition.

  In the gel composition according to the present invention, the cation component of the ionic liquid is ammonium and derivatives thereof, imidazolinium and derivatives thereof, pyridinium and derivatives thereof, pyrrolidinium and derivatives thereof, pyrrolium and derivatives thereof, pyrazinium and derivatives thereof , Pyrimidinium and its derivatives, triazonium and its derivatives, triazinium and its derivatives, triazine derivative cations, quinolinium and its derivatives, isoquinolinium and its derivatives, indolinium and its derivatives, quinoxalinium and its derivatives, piperazinium and its derivatives, oxazolinium and its derivatives , Thiazolinium and its derivatives, morpholinium and its derivatives, piperazine and its derivatives At least one member selected from the group consisting of can contain.

The anionic component of the ionic liquid includes a sulfonic acid group anion (—SO ₃ ⁻ ), a sulfate group anion (—OSO ₃ ⁻ ), a carboxyl group anion (—COO ⁻ ), BF ₄ ⁻ , PF ₆ ⁻ , bis ( Trifluoromethylsulfonyl) imide anion ((CF ₃ SO ₂ ) ₂ N ⁻ ), tris (trifluoromethylsulfonyl) carboanion ((CF ₃ SO ₂ ) ₃ C ⁻ ), NO ₃ ⁻ , and nitro group anion (− At least one selected from the group consisting of NO ₂ ⁻ ).

  Furthermore, in the gel of the present invention, the gelling agent can be a compound containing at least two polar groups or two or more reactive functional groups.

In the method for producing a gel composition according to the present invention, as the gel forming step,
Preparing a first gelling agent containing two or more first reactive functional groups and a second gelling agent containing two or more second reactive functional groups as the gelling agent;
Dissolving or dispersing the first gelling agent and the second gelling agent in the ionic liquid;
A step of polymerizing the first gelling agent and the second gelling agent.

In one embodiment of the present invention, it is preferable that the ionic liquid is an ionic liquid in which at least a part of the conductive polymer is dissolved. The heat dissipation method characterized by releasing heat through the gel-like composition in any one of 1-6 is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the gel-like composition with high heat conductivity which can be applied to a heat dissipation use, and its manufacturing method can be provided.

  The components of the present invention will be described in detail.

(Ionic liquid)
The ionic liquid used in the present invention is formed from a cation and an anion, which is a liquid at room temperature (for example, at 10 ° C. to 30 ° C.), and is also called a room temperature molten salt. However, the ionic liquid of the present invention is not limited to this range, and for example, those that become liquid at a temperature of 100 ° C. or lower are also included in the scope of the present invention.

  Although there is no restriction | limiting in particular as a cation component which forms this ionic liquid, From the viewpoint of improving the chemical stability and electroconductivity of an ionic liquid, it is preferable to use the cation containing various quaternary nitrogen. For example, ammonium and its derivatives, imidazolinium and its derivatives, pyridinium and its derivatives, pyrrolidinium and its derivatives, pyrrolinium and its derivatives, pyrazinium and its derivatives, pyrimidinium and its derivatives, triazonium and its derivatives, triazinium and its derivatives, triazine Derivative cations, quinolinium and its derivatives, isoquinolinium and its derivatives, indolinium and its derivatives, quinoxalinium and its derivatives, piperazinium and its derivatives, oxazolinium and its derivatives, thiazolinium and its derivatives, morpholinium and its derivatives and piperazine and its derivatives It is preferable to use at least one selected from the group consisting of Arbitrariness. Here, the derivative means that at least one hydrogen atom that can be substituted in the basic compound is an aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic hydrocarbon group, hydroxyl group, carbonyl group, carboxyl group. A compound substituted with a substituent such as a group, an ether group, an ester group, an acyl group or an amino group.

The anion component forming the ionic liquid is not particularly limited, but from the viewpoint of enhancing the conductivity of the ionic liquid, a sulfonic acid group anion (—SO ₃ ⁻ ) and a sulfate group-containing anion (—OSO ₃ ⁻ ). , Carboxyl group anion (—COO ⁻ ), BF ₄ ⁻ , PF ₆ ⁻ , bis (trifluoromethylsulfonyl) imide anion ((CF ₃ SO ₂ ) ₂ N ⁻ ), (tris (trifluoromethylsulfonyl) carboanion ( It is preferable to use at least one selected from the group consisting of (CF ₃ SO ₂ ) ₃ C ⁻ ), NO ₃ ⁻ , and a nitro group anion (—NO ₂ ⁻ ).

Examples of the anion component preferably used in the present invention include an atomic group containing a sulfonate group anion (—SO ₃ ⁻ ) and a sulfate group anion (—OSO ₃ ⁻ ). These are respectively described as R _A SO ₃ ⁻ and R _B OSO ₃ ⁻ (where R _A and R _B are an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an ether, A substituent containing a group, an ester group, an acyl group or the like, and may contain a fluorine atom).

R _A SO ₃ ^- as, for _{example, p-CH 3 C 6 H} 4 SO 3 - (p- toluenesulfonate _{anion), C 6 H 5 SO 3} - ( benzenesulfonic acid anion), and the like. Moreover, in R _A SO ₃ ^— , R _A containing a fluorine atom is more preferable. For example, CF ₃ SO ₃ ⁻ , CHF ₂ CF ₂ CH ₂ SO ₃ ⁻ , CHF ₂ — (CF ₂ ) ₃ —CH ₂ SO ₃ ^{— and the} like can be mentioned.

Examples of R _B OSO ₃ ^— include CH ₃ CH ₂ OCH ₂ CH ₂ OSO ₃ ^— , C ₆ H ₅ OCH ₂ CH ₂ OSO ₃ ^{—, and the} like. In R _B OSO ₃ ^— , R _B containing a fluorine atom is more preferable. For _{example, CHF 2 CF 2 CH 2 OSO} 3 -, CHF 2 - (CF 2) 3 -CH 2 OSO 3 -, CF 3 - (CF 2) 2 -CH 2 OSO 3 -, CF 3 - (CF 2) 6 -CH ₂ OSO _3- ^{and the} like.

In addition, examples of the anion component preferably used in the present invention include an atomic group containing a carboxyl group anion (—COO ⁻ ). For _{^{example, R C COO -, HOOCR C}} COO -, - OOCR C COO -, NH 2 CHR C COO - , etc. can be mentioned (wherein, R _C is an aliphatic hydrocarbon group, alicyclic hydrocarbon group, an aromatic A substituent containing an aromatic hydrocarbon group, an ether group, an ester group, an acyl group, or the like, or may contain a fluorine atom).

Moreover, as an anion component preferably used in the present invention, an atomic group containing a nitro group anion (—NO ₂ ⁻ ) can be mentioned. For example, R _D NO ₂ ^{— and the} like can be mentioned (where R _D is a substituent containing an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an ether group, an ester group, an acyl group, or the like). Represents a group, and may also contain a fluorine atom).

  The ionic liquid used in the present invention can be synthesized by a known method such as an anion exchange method, an acid ester method, or a neutralization method.

(Gelling agent)
There is no restriction | limiting in particular in the gelatinizer used in this invention, The general method used for gelatinization can be used. Among them, it is preferable for the purpose of the present invention to use a compound containing two or more polar groups or two or more reactive functional groups. Specific examples of polar groups include hydroxyl, halide, carbonyl, carboxyl, ether, ester, amide, amino, acid amide, sugar amide, and vinyl functional groups. It is done. Two or more polar groups may be the same or different from each other. Moreover, a reactive functional group means the functional group which bridge | crosslinks the molecular chain of a gelatinizer by chemical reaction. Examples of the reactive functional group include an isocyanate group, a group having an unsaturated double bond, a nucleophilic group having active hydrogen, an epoxy group, an amine group, and a carboxyl group. Here, an isocyanate group and a nucleophilic group having active hydrogen react, a group having an unsaturated double bond reacts with a nucleophilic group having active hydrogen, and an epoxy group reacts with an amine group or a carboxyl group. To crosslink. Gelling agents containing two or more polar groups or two or more reactive functional groups are three-dimensional due to intermolecular bonds such as hydrogen bonds generated between two or more polar groups or covalent bonds generated by two or more reactive functional groups. A network structure is formed, and the ionic liquid in which at least a part of the conductive polymer is dissolved easily gels by this three-dimensional network structure. It can be observed with a dark field optical microscope or the like that the gelling agent forms a gel composition by forming a three-dimensional network structure.

Examples of the compound containing two or more polar groups include pentaerythritol, β-D-glucose, α-cyclodextrin, polyvinyl alcohol, polyvinyl polymer (polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropolopylene copolymer, etc. ), Polyether polymers (polyethylene oxide derivatives, etc.), polyester polymers, polyurethane polymers, polyamide polymers, polyacrylonitrile polymers, polycarbonate polymers, proteins (such as glucose oxidase), polysaccharides, Examples thereof include sugar derivatives and molecular aggregates (such as bimolecular films composed of C ₈ AzoC ₁₀ N ⁺ Br ⁻ or diazoalkyl ammonium salts). Moreover, as a compound containing two or more reactive functional groups, an isocyanate compound having two or more isocyanate groups, a compound having two or more groups having an unsaturated double bond, or a compound having two or more nucleophilic groups having active hydrogen , An epoxy compound having two or more epoxy groups, an amine compound having two or more amine groups, a carboxy compound having two or more carboxyl groups, and the like.

  In the gel composition according to the present invention, the mass concentration of the gelling agent with respect to the ionic liquid is preferably 3% by weight or more and 50% by weight or less. If it is less than 2% by weight, gelation becomes insufficient, and if it exceeds 50% by weight, the elasticity and flexibility as a gel-like material are lost and become hard, and the thermal resistance at the interface increases when used for connection. . From this viewpoint, 3% by weight or more and 40% by weight or less is more preferable.

(Method for producing gel composition)
There is no restriction | limiting in particular about the manufacturing method of the gel-like composition concerning this invention. A general gelation technique can be used. Especially, it is preferable to include the gelatinization process of gelatinizing an ionic liquid using a gelatinizer. By including such a step, the ionic liquid can be gelated as it is, and a gel-like composition having high thermal conductivity can be obtained.

The gelation step of gelling the ionic liquid using the gelling agent is not particularly limited, but depending on the type of the gelling agent, may include a step of dissolving or dispersing the gelling agent in the ionic liquid. preferable. Examples of such a gelling agent include gelling agents that are compatible or highly compatible with ionic liquids, for example, compounds having two or more polar groups, and the cation and anion of the polar group and ionic liquid. A compound having a high affinity with at least either is preferably used. For example, pentaerythriol, β-D-glucose, α-cyclodextrin, polyvinyl alcohol, polyvinyl polymer (polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, etc.), polyether polymer (poly Ethylene oxide derivatives), polyester polymers, polyurethane polymers, polyamide polymers, polyacrylonitrile polymers, polycarbonate polymers, proteins (such as glucose oxidase), polysaccharides, sugar derivatives, molecular aggregates (C ₈ A bimolecular film made of AzoC ₁₀ N ⁺ Br ^- or a diazoalkyl ammonium salt, etc.) is preferably used.

  In addition, the gelling step of gelling an ionic liquid in which at least a part of the conductive polymer is dissolved using a gelling agent is performed by using two or more first gelling agents depending on the type of gelling agent. A step of preparing a first gelling agent containing a reactive functional group and a second gelling agent containing two or more reactive functional groups, and ions in which at least a part of the conductive polymer is dissolved It is preferable to include a step of dissolving or dispersing the first gelling agent and the second gelling agent in the functional liquid and a step of polymerizing the first gelling agent and the second gelling agent. . By polymerizing the first gelling agent and the second gelling agent, an ionic liquid in which at least a part of the conductive polymer is dissolved can be easily gelled. In the step of dissolving or dispersing the first gelling agent and the second gelling agent in the ionic liquid, the first gelling agent and the second gelling agent are dissolved or dispersed in the ionic liquid. The order is not particularly limited, but it is not preferable to directly mix the first gelling agent raw material and the second gelling agent raw material because an abrupt reaction may occur and solidify as it is.

  As a combination of such a first gelling agent and a second gelling agent, (a) a combination of a compound having two or more isocyanate groups and a compound having two or more nucleophilic groups having active hydrogen, (b) A combination of a compound having two or more unsaturated double bonds and a compound having two or more nucleophilic groups having active hydrogen, and (c) a combination of an epoxy compound having two or more epoxy groups and a polyamine and / or acid anhydride. Preferably mentioned.

  For example, in the combination (a), a compound having two or more nucleophilic groups having a compound having two or more isocyanate groups is polymerized by a polyaddition reaction to dissolve at least a part of the conductive polymer. The ionic liquid is gelled. Examples of the compound having two or more isocyanate groups include 2,4-toluene diisocyanate, 4,4′-diphenylene diisocyanate, hexethylene diisocyanate, hydrogenated 4,4′-diphenylene diisocyanate, hexethylene diisocyanate, and hexethylene diisocyanate. And a polymer of isocyanate ethyl methacrylate. Examples of the compound having two or more nucleophilic groups having active hydrogen include polyol compounds such as diol, triol, and tetraol, polyamine compounds such as diamine, triamine, and tetraamine, and polyamine compounds such as dicarboxylic acid, tricarboxylic acid, and tetracarboxylic acid. Examples thereof include carboxylic acid. The compounding ratio of the compound having two or more isocyanate groups as the first gelling agent and the compound having two or more nucleophilic groups having active hydrogen as the second gelling agent is not particularly limited, but the chemical equivalent A ratio of 2: 1 to 1: 2 is preferred. The mass concentration of the total amount of the first gelling agent and the second gelling agent with respect to the ionic liquid is preferably 5% by weight or more and 40% by weight or less.

  Moreover, a catalyst can be used in order to advance the said polyaddition reaction efficiently. As such a catalyst, a tin-based catalyst (dibutyltin dilaurate) and / or an amine-based catalyst which is a catalyst for polyurethane synthesis is preferably used. Such a catalyst is 0.1 mass based on the total of the compound having two or more isocyanate groups as the first gelling agent and the compound having two or more nucleophilic groups having active hydrogen as the second gelling agent. % To 5% by weight is preferable, and 0.2% to 2% by weight is more preferable.

(Inorganic filler)
Although the heat-dissipating gel-like composition can be obtained by the method described above, it goes without saying that various fillers having excellent thermal conductivity may be added to this composition, and by adding such a filler, higher thermal conductivity can be obtained. Can be obtained. Fillers include metal powders such as copper, silver and aluminum, carbon powder, and inorganic and ceramic powders such as silica, aluminum nitride, silicon nitride, boron nitride, alumina, aluminum hydroxide, magnesium hydroxide, magnesium oxide, and zinc oxide. , Etc. can be illustrated. These fillers show better thermal conductivity as the addition amount increases, but they must be flexible so that a small thermal resistance junction between the heating element and the heat dissipation body can be realized. Is determined. The optimum addition amount is also affected by the particle size of the filler and the shape of the particles. As such an example, a method of adding a plurality of fillers having different particle diameters can be exemplified. The type of filler varies depending on the purpose and location of the heat dissipation material, and is selected depending on conditions such as whether heat conduction and electrical insulation are required or whether both heat conduction and electric conduction are required. In the present invention, the filler to be added is not particularly limited, and fillers generally used for a heat dissipating gel, a heat dissipating rubber, a heat dissipating sheet, a heat dissipating paste and the like are also effective for the gel composition of the present invention. These fillers are added by kneading and dispersing with the gel composition of the present invention. There is no particular limitation on the method of addition, and a method generally used for filler dispersion can be preferably used.

  The addition amount varies depending on the kind of additive, particle size, etc., but in the case of the gel composition of the present invention, it is generally preferable that the amount is in the range of 20 wt% to 1000 wt% of the gel composition. A range of 30 wt% to 800 wt% is more preferable, and a range of 50 wt% to 500 wt% is most preferable. The gel composition according to the present invention is more flexible than silicon rubber and acrylic rubber usually used for heat conductive sheets, so it has high adhesion to a heat source and low thermal resistance even when the same amount of inorganic filler is mixed. There is a feature to say. Further, when trying to obtain a heat dissipation composition having the same softness, more filler can be added, and as a result, higher heat conduction characteristics can be realized.

(How to use gel composition, electronic device using gel composition)
Next, as an example, a method of actually using the gel composition of the present invention for the purpose of heat dissipation will be described by taking cooling of the CPU as an example. For example, FIG. 1 shows a connection in the case where cooling is performed by bringing a heat sink into contact with a heating element such as a CPU.

In FIG. 1, (1) is a heat sink, (2) is a heat dissipation gel composition, and (3) is a heating element such as a CPU. By connecting the heat dissipating gel composition as in (2), a connection having a small thermal resistance is possible. However, the effect of heat dissipation, that is, the magnitude of the heat resistance can be estimated as follows, for example. That is, the temperature of the CPU core part is set to (Th), and the temperature (Tf) at a specific place in the heat radiating fin is measured by a CA thermocouple. At this time, the lower the temperature of the heating element and the higher the temperature of the radiation fin, the smaller the thermal resistance, and the thermal resistance (unit: ° C./W) can be estimated according to the following formula-1.
Thermal resistance Hr = (Th−Tf) / W (Formula-1)
The value of the thermal resistance varies depending on the performance of the radiating fin, the heat generation characteristics of the heating element, etc., so it cannot be regarded as an absolute value, but by making these conditions constant, a relative comparison of the thermal resistance characteristics can be made. It is possible to do.

  Such a structure is very useful for cooling a high-performance CPU. Further, it is useful not only for CPUs but also for chip sets, DSPs, memories, etc. that generate heat. In addition, by using this structure, the heat sink of a personal computer, particularly a notebook personal computer, can be reduced in size, and it is useful for noise reduction by lowering the fan capacity. It can be used for various electronic devices such as servers, routers, mobile phones, video cameras, video camcorders, PDPs, and liquid crystal televisions that have heat generating electronic components other than personal computers.

(Measurement of heat conduction)
The thermal diffusivity was measured at 10 Hz in an atmosphere of 20 ° C. using a thermal diffusivity measuring apparatus (“LaserPit” available from ULVAC Riko Co., Ltd.) by an optical alternating current method. The thermal conductivity was calculated from the measured thermal diffusivity using values of density and specific heat. The density of the gel composition film was calculated by dividing the weight (g) of the film by the volume (cm ³ ) calculated by the product of the length, width and thickness of the film. In addition, the average value measured by arbitrary 10 points | pieces was used for the thickness of a film.

  Hereinafter, a heat-dissipating gel-like composition obtained by gelling an ionic liquid using a gelling agent will be specifically described based on examples. Of course, the present invention is not limited to the following examples.

Example 1
10 ml of EMImTsO was gelled using a tetrahydrofuran solution in which a polyvinylidene fluoride-hexafluoropropylene copolymer was dissolved as a gelling agent to obtain a gel composition. The gelation conditions were such that the mass concentration of the gelling agent with respect to 10 ml of EMImTsO was 1.2 g, and the mixture was heated at 60 ° C. for 3 hours in a reactor equipped with a reflux condenser to obtain a uniform solution. This solution was applied onto a PET substrate using a doctor blade, and tetrahydrofuran was evaporated to obtain a gel composition. This gel sheet (Sheet-A) was a self-supporting sheet even when peeled from the PET film. As a result of measuring the thermal conductivity of the obtained gel-like composition by the thermal conductivity measurement method, the value was 0.6 W / mK.

(Example 2)
A gel-like composition was obtained in the same manner as in Example 1 except that EMIm. ((CF ₃ SO ₂ ) ₂ N) (abbreviated as EMImTFSI, hereinafter the same) was used as the ionic liquid instead of EMImTsO. At this time, the mass concentration of the gelling agent with respect to 10 ml of EMImTFSI was 1.0 g, so that a self-supporting film having substantially the same flexibility was obtained. The thermal conductivity of the obtained gel-like sheet (Sheet-B) was measured by the above measuring method. As a result of measuring the thermal conductivity of the obtained gel composition, the value was 0.4 W / mK.

(Example 3)
First, after adding 100 ppm of dibutyltin dilauric acid catalyst to 10 ml of EMImTsO, polyoxyethylene glycerin (molecular weight 1200) is mixed, and then tolylene diisocyanate is added so that the molar ratio is 1: 1. Was prepared. The total amount of polyoxyethylene glycerin and tolylene diisocyanate was mixed so as to be 6 wt% with respect to the EMImTsO solution. And the gel-like composition was obtained by standing the said mixed solution for 30 minutes at the temperature of 80 degreeC. The thermal conductivity of the obtained gel composition sheet (Sheet-C) was measured by the measurement method described above. The value was 0.5 W / mK.

  The thermal conductivity of silicone rubber (KE951 manufactured by Shin-Etsu Silicone Co., Ltd.) most commonly used as a heat dissipation sheet was measured in the same manner as in the examples. As a result, the thermal conductivity was 0.18 W / mK. The thermal conductivity of the ionic liquid gel sheet of the present invention shown in Examples 1 to 3 is 0.4 to 0.6 W / mK, which is superior to the silicone rubber sheet. From this, the high thermal conductivity of the gel sheet of the present invention was confirmed.

(Examples 4 to 6)
Boron nitride powder (manufactured by AC Co., Ltd .: trade name BN (average particle size 50 μm) to the gel compositions (sheet-A, sheet-B, sheet-C (each 100% by weight)) obtained in Examples 1 to 3 )) 200 wt% was added and kneaded to prepare a heat dissipation sheet. The obtained heat-dissipating sheet has sufficient flexibility, and the thermal conductivity of each sheet is sheet-A: 4.8 W / mK, sheet-A: 4.2 W / mK sheet-A: 4. It was 5 W / mK, and it was confirmed that the product had excellent heat conduction characteristics.

(Examples 7 to 9)
300 mg of aluminum oxide (manufactured by Showa Denko KK: trade name AL30) to the gel compositions (sheet-A, sheet-B, sheet-C (each 100% by weight)) obtained in Examples 1 to 3 % And kneaded to prepare a heat dissipation sheet. The obtained heat-dissipating sheet has sufficient flexibility, and the thermal conductivity of each sheet is as follows: sheet-A: 3.6 W / mK, sheet-A: 3.1 W / mK sheet-A: 3. It was 5 W / mK, and it was confirmed that the product had excellent heat conduction characteristics.

(Example 10)
Furthermore, in order to demonstrate the effect of the gel sheet of the present invention, the measurement of the thermal resistance at the joint between the heating element and the heat sink when using the heat dissipation sheet made of the mixture of sheet-A and boron nitride obtained in Example 4 was performed. A simulation cell as shown in FIG. 1 was produced.

That is, the heat-dissipating gel-like composition of the present invention was sandwiched between a CPU core and a heat sink, a constant pressure was applied, and then a constant power was applied to the transistor to generate heat (heat generation amount W). The experimental environment this time is as follows. CPU: P3 (800 MHz), heat sink: FC-PAL35T, memory: SDRAM 128MB, OS: Windows (registered trademark) me, measurement conditions: temperature measurement after completion of Loop in Super PI 209,000 lines. The temperature measurement point is a part of the CPU core. When the applied pressure was 2 N / cm ² , the CPU temperature was 64 ° C. and the thermal resistance was 0.81 ° C./W. When the pressure is 5 N / cm ² , the CPU temperature is 62 ° C. and the thermal resistance is 0.72 ° C./W, and when the pressure is 15 N / cm ² , the CPU temperature is 60 ° C. and the thermal resistance is 0.70. When the pressure was 20 N / cm ² , the CPU temperature was 56 ° C. and the thermal resistance was 0.68 ° C./W. As a result, the temperature of the CPU was suppressed to 64 ° C. or less, and the effectiveness of the heat dissipation sheet of the invention was proved.

(Comparative Example 1)
Two-component addition reaction type silicone gel (manufactured by Toray Dow Corning Co., Ltd .: CY52-285A / B) as a matrix resin, and two-component addition reaction type liquid silicone rubber (made by Toray Dow Corning Co., Ltd .: product) No. CY52-287A / B) was blended in an amount of 50% by weight, and then 200% by weight of boron nitride powder (manufactured by AC Corporation: trade name BN (average particle size 50 μm)) was added and kneaded to obtain a heat dissipation sheet. The thermal conductivity was 2.8 W / mK. From this result, even when the same amount of filler was added, the usefulness of the gel heat radiation sheet of the present invention could be confirmed.

(Comparative Example 2)
300% by weight of aluminum oxide (manufactured by Showa Denko KK: trade name AL30) was added to the same matrix resin as in Comparative Example 1, and kneaded by the same method to obtain a heat radiating sheet. The thermal conductivity was 1.9 W / mK. From this result, even when the same amount of filler was added, the usefulness of the gel heat radiation sheet of the present invention could be confirmed.

  As described in the above examples, the gel-like composition obtained by gelling the ionic liquid has high thermal conductivity. According to the present invention, the gel-like composition is more than the conventional heat-dissipating gel-like composition. A gel-like composition having high thermal conductivity is obtained. The gel composition having high thermal conductivity according to the present invention can be applied to a wide range of uses as a heat radiation grease and a heat radiation sheet.

  From the above results, it is clear that the gel composition of the present invention has better heat dissipation characteristics than the conventional silicone gel when at least the same amount of filler having the same composition, the same particle size, and the same shape is added. Thus, the usefulness of the ionic liquid gel of the present invention was demonstrated for the purpose of heat dissipation.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Example of using the heat diffusion film of the present invention together with a heat sink for cooling a CPU

Explanation of symbols

1 CPU
2 Heat dissipation film of the present invention 3 Heat sink

Claims (9)

  A heat-dissipating gel composition characterized by being obtained by gelling an ionic liquid containing at least an ionic liquid and a gelling agent.   A heat-dissipating gel composition, comprising an ionic liquid and a gelling agent, wherein the gelling agent has a mass concentration of 2 wt% or more and 50 wt% or less with respect to the ionic liquid.   The heat-dissipating gel composition according to claim 1 or 2, wherein a heat conductive inorganic filler is mixed in an amount of 20 to 1000 wt% with respect to the gel composition.   The cation component of the ionic liquid is ammonium and derivatives thereof, imidazolinium and derivatives thereof, pyridinium and derivatives thereof, pyrrolidinium and derivatives thereof, pyrrolinium and derivatives thereof, pyrazinium and derivatives thereof, pyrimidinium and derivatives thereof, triazonium and derivatives thereof , Triazinium and its derivatives, triazine derivative cations, quinolinium and its derivatives, isoquinolinium and its derivatives, indolinium and its derivatives, quinoxalinium and its derivatives, piperazinium and its derivatives, oxazolinium and its derivatives, thiazolinium and its derivatives, morpholinium and its At least one selected from the group consisting of derivatives thereof, piperazine and derivatives thereof Radiating gel composition according to claim 1 comprising a class. The anionic component of the ionic liquid is a sulfonate group anion (—SO ₃ ⁻ ), a sulfate group anion (—OSO ₃ ⁻ ), a carboxyl group anion (—COO ⁻ ), BF ₄ ⁻ , PF ₆ ⁻ , bis (tri Fluoromethylsulfonyl) imide anion ((CF ₃ SO ₂ ) ₂ N ⁻ ), tris (trifluoromethylsulfonyl) carbanion ((CF ₃ SO ₂ ) ₃ C ⁻ ), NO ₃ ⁻ , and nitro group anion (—NO ₂ ^-) radiating gel composition according to claim 1 comprising at least one member selected from the group consisting of.   The gel composition for heat dissipation according to any one of claims 1 to 5, wherein the gelling agent is a compound containing at least two or more polar groups or two or more reactive functional groups. As the gel forming step,
Preparing a first gelling agent containing two or more first reactive functional groups and a second gelling agent containing two or more second reactive functional groups as the gelling agent;
Dissolving or dispersing the first gelling agent and the second gelling agent in the ionic liquid;
Polymerizing the first gelling agent and the second gelling agent,
The manufacturing method of the gel-like composition for heat dissipation in any one of Claims 1-6.   8. The method for producing a gel composition for heat dissipation according to claim 7, wherein the ionic liquid in claim 7 is an ionic liquid in which at least a part of the conductive polymer is dissolved.   A heat dissipating method characterized in that heat is released from the exothermic electronic component through the gel composition according to any one of claims 1 to 6.

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