TW201540821A - Heat dissipating film, dispersion liquid for thermal radiation layer use, manufacturing method of heat dissipating films, and solar cells - Google Patents

Abstract

The present invention provides a heat dissipating film having high mechanical strength and flexibility, which is produced by laminating a thermal radiation layer, which dissipates heat through infrared radiation and has excellent electrical insulation and thermal resistance, onto metal layers having excellent thermal conductivity. Further, the present invention provides a dispersion liquid for thermal radiation layer use to produce the heat dissipating films, a manufacturing method of heat dissipating films using the dispersion liquid for thermal radiation layer use, and solar cells produced by using the heat dissipating films. The present invention provides a heat dissipating film which has a heat conducting layer and a flexible thermal radiation layer laminated onto the heat dissipating film. The aforementioned heat conducting layer is a metal membrane, and the aforementioned thermal radiation layer contains water-insoluble inorganic compounds and thermally resistant synthetic resin. The content of the water-insoluble inorganic compounds in the aforementioned thermal radiation layer relative to the overall thermal radiation layer is from 30% to 90% by weight. The thermal radiation rate of the aforementioned thermal radiation layer is more than 0.8, and the dielectric breakdown strength is more than 10 kV/mm.

Description

Heat dissipation film, dispersion for heat radiation layer, method for manufacturing heat dissipation film, and solar cell

The present invention relates to a heat dissipating film for discharging heat generated by an IC chip or an LED or the like built in an electronic device. Moreover, the present invention relates to a dispersion liquid for a heat radiation layer for producing the heat dissipation film, a heat radiation film production method using the heat radiation layer dispersion liquid, and a solar battery using the heat dissipation film.

In recent years, the size of electronic devices has become smaller, lighter, and thinner. On the other hand, the demand for multi-functionality and high functionality of IC chips built in electronic devices has increased, and the degree of integration of circuits has been increasing. . These IC chips generate heat due to leakage current during operation, dynamic power, or resistance of a wire. If the amount of heat generated by the IC chip is increased due to the high integration of the circuit, the semiconductor may be damaged, and malfunctions such as malfunction or malfunction of the electronic device may occur. In addition, in recent years, the use of LEDs for illumination has been increasing. However, if the amount of heat generation is increased due to high integration, problems such as shortened life of the LEDs occur. Therefore, the thermal design of these electronic components is very important. Various heat dissipating films have been developed as a preferable heat dissipating material that can cope with miniaturization or thinning of electronic equipment. For the heat-dissipating film, in addition to high heat dissipation by heat transfer or radiation, electrical insulation is also required for visual use.

As such a heat dissipating film, for example, Patent Document 1 discloses that a heat dissipating film is used in which a graphite sheet having a high thermal conductivity is used, and a heat dissipating film having a radiation effect inorganic layer is formed on the surface thereof. The heat dissipation film disclosed in Patent Document 1 is lightweight because of its high heat conductivity. Transmission capacity is also high. However, it is costly compared to a metal film of copper or aluminum used as a heat transfer layer. Further, since the mechanical strength of the graphite sheet is weak compared with the metal film, there is a high possibility that the film is broken during the operation of the film.

Further, for example, Patent Documents 2 to 4 disclose a flexible heat dissipation film in which a metal film is used as a heat transfer layer and a heat radiation layer is formed on the surface thereof. However, the heat dissipating film disclosed in Patent Documents 2 and 3 uses a polyfluorene resin as a binder of an inorganic material in the heat radiating layer, but the heat radiating layer using the polyoxynoxy resin has low heat resistance, and The metal film of the hot layer has poor adhesion and is easily peeled off. The heat dissipating film disclosed in Patent Document 4 uses powder graphite instead of inorganic material as a filler of the heat radiating layer, and has excellent heat dissipation properties and good adhesion to the heat transfer layer by setting the relationship between the average particle diameter and the film thickness. However, when a large amount of graphite is filled in the resin in order to improve heat dissipation, the problem of electrical insulation cannot be ensured.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2008-78380

Patent Document 2: Japanese Patent Laid-Open Publication No. 2004-200199

Patent Document 3: Japanese Laid-Open Patent Publication No. 2002-371192

Patent Document 4: Japanese Laid-Open Patent Publication No. 2008-120065

An object of the present invention is to provide a heat dissipating film having high mechanical strength and flexibility, which is excellent in heat conductivity by laminating heat radiation having excellent heat dissipation, electrical insulation, and heat resistance by infrared radiation. Made of metal film. Moreover, an object of the present invention is to provide a dispersion liquid for a heat radiation layer for producing the heat dissipation film, a method for producing a heat dissipation film using the dispersion liquid for the heat radiation layer, and a solar battery using the heat dissipation film.

The present invention relates to a heat dissipating film having a heat transfer layer and a flexible heat radiating layer laminated on the heat transfer layer, wherein the heat transfer layer is a metal film, and the heat radiation layer contains water insoluble The inorganic compound and the heat-resistant synthetic resin, wherein the content of the water-insoluble inorganic compound in the heat radiation layer is 30 to 90% by weight based on the entire heat radiation layer, and the heat radiation layer has a heat radiation rate of 0.8 or more and is insulated. The breaking strength is 10 kV/mm or more.

The invention is described in detail below.

The present inventors have found that by laminating heat radiation layer on a heat transfer layer composed of a metal film, it is possible to obtain high mechanical strength and excellent heat dissipation, electrical insulation, heat resistance, and flexibility. The heat radiation film is used to complete the present invention; the heat radiation layer contains a water-insoluble inorganic compound and a heat-resistant synthetic resin in a specific ratio, and the heat radiation rate and the dielectric breakdown strength are at a specific value or more.

The heat dissipation film of the present invention has a heat transfer layer.

The heat transfer layer has a function of conducting heat emitted from the heat source to the heat radiation layer.

The heat transfer layer is a metal film.

The metal film is not particularly limited as long as it is composed of a metal having a high thermal conductivity. Specifically, the thermal conductivity of the metal constituting the metal film is preferably 30 W/m‧K or more, and more preferably 200 W/m‧K or more in order to improve heat dissipation characteristics.

Examples of the metal film include a copper film, an aluminum film, a gold film, a silver film, a tin film, a nickel film, and an alloy film containing a metal constituting the film. Among them, in terms of cost, a copper film or an aluminum film is preferable.

A preferred lower limit of the thickness of the above metal film is 10 μm, and a preferred upper limit is 1000 μm. If the thickness of the above metal film is less than 10 μm, sufficient heat transfer performance may not be exhibited. When the thickness of the above-mentioned metal film exceeds 1000 μm, the obtained heat-dissipating film may be excessively heavy or may be inferior in flexibility. A more preferable lower limit of the thickness of the above metal film is 100 μm, a more preferable upper limit is 500 μm, and a further preferred upper limit is 300 μm.

The heat dissipation film of the present invention has a heat radiation layer.

The heat radiation layer has a heat radiated from the heat transfer layer in the form of infrared rays The role of shooting.

The above heat radiation layer contains a water-insoluble inorganic compound.

In the present invention, the term "water-insoluble" means that the solubility in 100 mL of water at 20 ° C is less than 1.0 g.

The water-insoluble inorganic compound preferably contains, for example, at least one selected from the group consisting of a cerium oxide compound, a silica-alumina compound, an aluminum compound, a calcium compound, a nitride, and coal ash. Among them, it is more preferable to contain a cerium oxide compound, a lanthanum aluminum compound, and coal ash. Further, from the viewpoint of heat radiation characteristics such as heat radiation rate, layered niobate minerals and coal ash are more preferable.

In the present specification, the above "layered citrate mineral" means a compound contained in a cerium oxide compound. In addition, the term "coal ash" refers to ash which is generated when coal is burned by thermal power generation such as fly ash or clinker ash. Among them, the cerium oxide compound and the aluminum compound which are main components are 80% of all components. A mixture of 95% water insoluble inorganic compounds.

Examples of the layered niobate mineral include mica, talc, kaolin, pyrophyllite, sericite, vermiculite, bentonite, bentonite, strontium, montmorillonite, and bead of natural or synthetic materials. Stone, saponite, lithium bentonite, nontronite, etc. Among these, in terms of producing a uniform heat-dissipating film at low cost, it is preferably a non-swelling clay mineral such as talc, kaolin, pyrophyllite, non-swelling mica or sericite, and more preferably selected from talc, At least one of a group consisting of kaolin, pyrophyllite, and non-swelling mica.

Examples of the cerium oxide compound other than the layered citrate minerals include ash, glass beads and the like.

Examples of the above ruthenium aluminum compound include zeolite and mullite.

Examples of the aluminum compound include spinel, aluminum hydroxide, alumina, and aluminum borate.

Examples of the calcium compound include calcium carbonate and the like.

Examples of the nitride include tantalum nitride, boron nitride, and the like.

The water-insoluble inorganic compound may be used singly or in combination of two or more. In the case of using coal ash, it is preferably used in combination with a water-insoluble inorganic compound other than coal ash.

According to the average particle diameter of the water-insoluble inorganic compound, the properties of the heat radiation layer of the obtained heat-dissipating film are also changed. Therefore, the water-insoluble inorganic compound is preferably used after selecting the particle diameter.

A preferred lower limit of the average particle diameter of the water-insoluble inorganic compound is 0.1 μm, and a preferred upper limit is 50 μm. A more preferred lower limit of the average particle diameter of the water-insoluble inorganic compound is 0.2 μm, a more preferred upper limit is 40 μm, and a further preferred lower limit is 0.5 μm, and a further preferred upper limit is 30 μm.

Further, the average particle diameter of the water-insoluble inorganic compound can be determined by measuring a particle size distribution using a laser diffraction type particle size distribution analyzer or the like.

The content of the water-insoluble inorganic compound in the heat radiation layer is 30% by weight or less, and the upper limit is 90% by weight based on the entire heat radiation layer. When the content of the water-insoluble inorganic compound is less than 30% by weight, the obtained heat-dissipating film may have high combustion property or may have poor heat dissipation characteristics. When the content of the water-insoluble inorganic compound is more than 90% by weight, when the dispersion for a heat radiation layer to be described below is stretched on a metal film or a substrate, coating unevenness is likely to occur, and the film thickness of the heat radiation layer is thinned. Damage to electrical insulation. A preferred lower limit of the content of the water-insoluble inorganic compound is 35% by weight, a preferred upper limit is 85% by weight, a still lower limit is 40% by weight, a still more preferred upper limit is 80% by weight, and a further preferred lower limit is 50% by weight. A preferred upper limit is 70% by weight, and a preferred lower limit is 60% by weight.

The heat radiation layer of the heat dissipation film of the present invention contains a heat resistant synthetic resin.

The above heat-resistant synthetic resin means a so-called super engineering plastic, and specific examples thereof include a polyimine resin, a polyamide amide resin, a fluororesin, a polyphenylene sulfide resin, and a polyfluorene resin. Resin, polyarylate resin, polyether oxime resin, polyether oxime resin, polyether ether ketone resin, polybenzoxazole resin, polybenzimidazole resin, and the like. Among them, In terms of excellent film properties or heat resistance, at least one of a polyimide resin and a polyamide amine imide resin is preferably used.

From the viewpoint of heat resistance, the heat resistant synthetic resin preferably has a structure containing no saturated cyclic hydrocarbon such as a cyclohexane ring. In addition, the heat-resistant synthetic resin is preferably a structure containing an aromatic ring, and further preferably an aromatic polyimine resin and an aromatic polyamine. At least one of the quinone imine resins.

The polyimine resin is a compound having a repeating structure of the following formula (1), and the polyamidoximine resin is a compound having a repeating structure of the following formula (2).

In the formula (1), R ¹ is an organic group which is tetravalent and has one or two benzene rings. Among them, R ^{1 is} preferably a structure represented by the following formula (3). When R ¹ is a structure represented by the following formula (3), the polyimine resin may have a structure represented by the following formula (3) as one of R ¹ or two or more types. Copolymer.

In the formula (2), R ² is an organic group which is trivalent and has one or two benzene rings. Among them, R ^{2 is} preferably a structure represented by the following formula (4). When the R ² is a structure represented by the following formula (4), the polyamidoximine resin may have a structure represented by the following formula (4) as a single R ² or two kinds. The above copolymer.

In the formulae (1) and (2), R ³ is an organic group which is divalent and has one or two benzene rings. Among them, R ^{3 is} preferably a structure represented by the following formula (5). When R ³ is a structure represented by the following formula (5), the polyimine resin and the polyamidoximine resin may have a structure represented by the following formula (5) as a single R ^{3 .} Further, it may be a copolymer having two or more kinds.

In particular, in view of the fact that the heat radiation layer of the obtained heat dissipation film is inexpensive and excellent in mechanical strength, R ¹ , R ² and R ^{3 are} preferably those represented by the following formula (6). The polyimine resin may have a structure represented by the following formula (6) as one of R ¹ and R ³ , or a copolymer of two or more. In addition, the polyamidoximine resin may have a structure represented by the following formula (6) as one of R ² and R ³ , or may have two or more copolymers.

Further, the heat resistant synthetic resin may be a copolymer composed of at least two of the above polyimine resin and the polyamidoximine resin.

The heat radiation layer may contain a colorant from the viewpoint of design.

Examples of the coloring agent include inorganic pigments and organic pigments. Among them, inorganic pigments are preferred from the viewpoint of heat resistance.

The inorganic pigment preferably contains a group selected from the group consisting of carbon black, an oxide pigment, a hydroxide pigment, a sulfide pigment, an inorganic salt pigment, a metal powder pigment, and a composite oxide pigment. At least one of them.

The carbon black is a fine particle of a carbon main body, and the type thereof is not particularly limited, and it is preferable to use a method called furnace black manufactured by a furnace method.

Examples of the oxide-based pigment include iron oxide, chromium oxide, titanium oxide, zinc oxide, ultramarine blue, and cobalt blue.

Examples of the hydroxide-based pigment include alumina white, iron oxide yellow, and viridian.

Examples of the sulfide-based pigment include zinc sulfide, zinc antimony white, cadmium yellow, cinnabar, and cadmium red.

Examples of the inorganic salt-based pigment include chrome yellow, molybdenum orange, zinc chromate, strontium chromate, precipitated barium sulfate, barite powder, calcium carbonate, and lead white.

Examples of the metal powder pigment include copper, iron, aluminum, and the like.

The above composite oxide-based pigment refers to a single compound which is uniformly compounded with a plurality of high-purity metal oxides and synthesized under high temperature conditions.

The content of the coloring agent is preferably 0.2% by weight, and preferably 15% by weight, based on the entire heat radiation layer. When the content of the coloring agent is less than 0.2% by weight, the heat radiation layer may not be sufficiently colored.

Further, in the case where carbon black is used as the coloring agent, a preferred upper limit of the content of the carbon black is 5% by weight. When the content of the carbon black is more than 5% by weight, the obtained heat-dissipating film may be inferior in electrical insulation.

In order to improve mechanical strength, the heat radiation layer may contain a coupling agent such as a decane coupling agent or a titanate coupling agent.

Examples of the decane coupling agent include an amine decane coupling agent, a urea decane coupling agent, a vinyl decane coupling agent, a methacrylic decane coupling agent, an epoxy decane coupling agent, an oxime decane coupling agent, and an isocyanate. A decane coupling agent or the like.

Examples of the titanate coupling agent include a titanate coupling agent having at least an alkylate group having 1 to 60 carbon atoms, and a titanate coupling having an alkyl phosphate group. A mixture, a titanate coupling agent having an alkyl phosphate group, a titanate coupling agent having an alkyl pyrophosic group, and the like.

These coupling agents may be mixed with the water-insoluble inorganic compound in advance, or may be mixed with the dispersion liquid for a heat radiation layer described below.

The content of the above coupling agent is preferably lower than that of the water-insoluble inorganic compound as a whole. The limit is 0.1% by weight, and the upper limit is preferably 3.0% by weight. When the content of the above coupling agent is less than 0.1% by weight, the effect of using a coupling agent may not be sufficiently exhibited. Even if it contains more than 3.0% by weight of the above coupling agent, there is a case where an effect corresponding to the amount of use cannot be obtained. A more preferred lower limit of the content of the above coupling agent is 0.5% by weight, and a more preferred upper limit is 2.0% by weight.

The heat radiation layer has a heat radiation rate of 0.8 or more, preferably 0.85 or more, more preferably 0.9 or more.

In addition, the "thermal radiance" can be measured using a thermal radiance measuring instrument such as TSS-5X (manufactured by Japan Sensor Co., Ltd.).

The heat radiation layer has an dielectric breakdown strength of 10 kV/mm or more, preferably 15 kV/mm or more, and more preferably 20 kV/mm or more from the viewpoint of use for an electronic device.

In addition, the above-mentioned "insulation breaking strength" can be measured by an insulation breakdown tester such as HAT-300 (manufactured by Hitachi Chemical Co., Ltd.) according to the method of ASTM D149.

The heat radiation layer is preferably used in the cross-cut test according to JIS K5600, and the adhesion to the metal film used as the heat transfer layer is classified into any one of 0 to 2, more preferably 0 or 1. The description of the above adhesion classification is shown in Table 1.

The adhesion of the heat radiation layer to the metal film used as the heat transfer layer can be adjusted by appropriately changing the type and content of the water-insoluble inorganic compound and the heat-resistant synthetic resin depending on the type of the metal film. For example, when an aluminum film is used as the metal film, the heat radiation layer preferably contains a polyimide resin or a polyamide resin as a heat resistant synthetic resin, and contains 30 to 90% by weight of a layered tannic acid. Salt minerals act as water-insoluble inorganic compounds.

The above heat radiation layer is preferably in the UL94 standard thin material vertical burning test (VTM test), and the flammability is classified as VTM-0. In the above VTM test, the film test piece was wound into a cylindrical shape, vertically mounted on a clamp, and contacted twice with a flame of a size of 20 mm for 3 seconds each, and the flammability shown in Table 2 was performed according to the burning behavior thereof. The determination of the classification.

In the heat radiation layer of the heat dissipation film, the film thickness is preferably 100 μm or less when subjected to the UL94 standard VTM test.

Further, the above heat radiation layer is preferably in the UL94 standard vertical burning test (V test), and the flammability is classified into V-0. In the above V test, the test piece was vertically mounted on a jig, and contacted with a flame of a size of 20 mm twice for 10 seconds each, and the flammability classification shown in Table 3 was judged based on the burning behavior.

Further, the above heat radiation layer is preferably in a UL94 standard 125 mm vertical burning test (5 V test), and the flammability is classified into 5 V-A or 5 V-B. In the above 5V test, the short test piece is vertically mounted on the jig, and is contacted with a flame of 125 mm in size for 5 times, each time for 5 seconds, and the flammability classification is determined according to the combustion behavior thereof, thereby further maintaining the flat test piece horizontally. Five times of contact with a 125 mm flame for 5 seconds was carried out, and the determination of the flammability classification shown in Table 4 was carried out based on the combustion behavior.

A preferred lower limit of the thickness of the above heat radiation layer is 20 μm, and a preferred upper limit is 100 μm. If the thickness of the above heat radiation layer is less than 20 μm, heat dissipation or electrical insulation may be lowered. If the thickness of the above heat radiation layer exceeds 100 μm, there is a case where the radiation efficiency with respect to the thickness of the heat radiation layer is deteriorated. A more preferable lower limit of the thickness of the above heat radiation layer is 30 μm.

The heat radiation layer may be laminated on one side of the heat transfer layer or may be laminated on both sides of the heat transfer layer. When the heat radiation layer is laminated on one surface of the heat transfer layer, the other layer of the heat transfer layer may be used to ensure an insulating layer of electrical insulation.

As the insulating layer, those containing the water-insoluble inorganic compound and the heat-resistant synthetic resin can be used in the same manner as the heat radiation layer.

The content of the water-insoluble inorganic compound in the insulating layer is preferably 30% by weight or less, and preferably 90% by weight, based on the entire insulating layer. When the content of the water-insoluble inorganic compound is less than 30% by weight, the flammability of the obtained heat-dissipating film may be high, or the heat-dissipating property may be poor. When the content of the water-insoluble inorganic compound is more than 90% by weight, coating unevenness is likely to occur when the dispersion liquid for an insulating layer is spread on a metal film or a substrate, or the electrical insulation is impaired in a portion where the thickness of the insulating layer is thinned. Sexual situation. A more preferred lower limit of the content of the above water-insoluble inorganic compound is 50% by weight, and a more preferred upper limit is 60% by weight.

A preferred lower limit of the thickness of the insulating layer is 20 μm, and a preferred upper limit is 100 μm. If the thickness of the insulating layer is less than 20 μm, electrical insulation properties may be lowered. When the thickness of the insulating layer exceeds 100 μm, the electrical insulating efficiency with respect to the thickness of the insulating layer may deteriorate. A more preferable lower limit of the thickness of the above insulating layer is 30 μm.

The heat dissipating film of the present invention preferably has a cooling temperature of 15 ° C or more when the upper surface of the ceramic heater having a thickness of 2.4 cm square and a thickness of 0.5 to 1.5 mm which is heated by inputting 3 W is provided in the same area as the ceramic heater. . If the above cooling temperature is less than 15 ° C, it may not be sufficient to exhibit sufficient heat dissipation performance when used as a heat dissipation film.

Furthermore, the above-mentioned cooling temperature means a temperature (heating temperature) at which a power of 3 W is input to a ceramic heater without a heat dissipating film and is in a balanced state, and a heat dissipating film is placed on the ceramic heater and a power of 3 W is used. The temperature difference from the temperature at which the ceramic heater is placed in equilibrium (the temperature of the film is set).

Further, as a ceramic heater having a thickness of 2.4 cm and a thickness of 0.5 to 1.5 mm, BPC10 (manufactured by BI Technologies Japan Co., Ltd.) or the like can be used.

The heat dissipating film of the present invention is preferably in the bending resistance test by the cylindrical mandrel method according to JIS K5600-5-1 (1999), wherein the diameter of the mandrel at which the heat radiation layer of the film starts to generate cracks is 10mm or less. If the diameter of the mandrel in which the crack is generated exceeds 10 mm, the flexibility may be poor. The diameter of the mandrel in which the heat radiation layer is cracked is more preferably 8 mm or less, and still more preferably 5 mm or less.

The heat-dissipating film of the present invention preferably has a tensile strength of ²⁵ N/mm ² or more. If the above tensile strength is less than ²⁵ N/mm ² , the film becomes easily broken and is difficult to handle. The preliminary tensile strength is more preferably 50 N/mm ² or more, and still more preferably 70 N/mm or more.

In addition, the tensile strength is determined by the measurement method according to JIS K7127-1, and the table-shaped precision universal testing machine "AGS-X" (manufactured by Shimadzu Corporation) is used, and the gap between the chucks is 80 mm. The measurement was carried out under the conditions of a tensile speed of 5 mm/min.

Since the heat dissipating film of the present invention is a metal film, the water vapor barrier property is extremely excellent. Specifically, the heat-dissipating film of the present invention preferably has a water vapor transmission rate of less than 0.01 g/m ² ‧day in an environment of 40 ° C and 90% RH.

Furthermore, the above-mentioned "water vapor transmission rate" can be obtained by using GTR-TEC gas-steaming The gas permeability measuring device or the like performs measurement.

The shape of the heat-dissipating film of the present invention is not particularly limited, and a shape corresponding to a heat-dissipating object (heat source) or a heat-dissipating method such as a flat plate shape, a ring shape, or a U-shape can be used.

The heat radiation layer in the heat dissipation film of the present invention can be produced by using a dispersion liquid for a heat radiation layer containing a dispersion medium, a water-insoluble inorganic compound which is a nonvolatile component, and a heat resistant synthetic resin and/or In the heat-resistant synthetic resin precursor, the content of the water-insoluble inorganic compound is 30% by weight or more and 90% by weight or less based on the total amount of the non-volatile component, and the content of the non-volatile component is more than the entire dispersion liquid for the heat radiation layer. 18% by weight and 65% by weight or less. Such a dispersion for a heat radiation layer is also one of the inventions.

The present inventors have found that it is possible to manufacture a previously difficult to manufacture by using a dispersion of a heat radiation layer having a content of a nonvolatile component and a content ratio of a water-insoluble inorganic compound in a nonvolatile component to a specific range. A heat dissipation film (heat dissipation film of the present invention) of a heat radiation layer excellent in heat dissipation properties, electrical insulation properties, adhesion to a metal film, and heat resistance.

Further, since the water-insoluble inorganic compound is inexpensive in the dispersion for a heat radiation layer of the present invention, the obtained heat-dissipating film becomes a highly productive one.

In the present specification, the term "non-volatile component" means a point which does not have a boiling point at normal pressure or a boiling point of 300 ° C or more. The water-insoluble inorganic compound and the heat-resistant synthetic resin in the dispersion liquid for a heat radiation layer of the present invention are the same as those of the heat dissipation film of the present invention, and thus the description thereof will be omitted.

As the precursor of the heat-resistant synthetic resin, for example, polylysine can be used, and by carrying out the ruthenium iodide, a polyimine resin or a polyamide amide resin can be obtained. As a method of carrying out the hydrazine imidization of the poly-proline, for example, a method in which poly-proline is heated and closed, and ruthenium is imidized, and a method in which poly-proline is chemically closed and ruthenium imidized is used. .

The method of imidating the polypyridic acid by heating and ring-closing, for example, dispersing the polyamic acid in a dispersion medium and heating it at 120 to 400 ° C for 0.5 to 10 hours The method of time.

When the heat-resistant synthetic resin precursor is blended in the dispersion for a heat radiation layer of the present invention, the preferred lower limit of the content of the heat-resistant synthetic resin precursor is 2% by weight, and the upper limit is preferably 45% by weight. When the content of the heat-resistant synthetic resin precursor is less than 2% by weight, the obtained heat-dissipating film may be inferior in electrical insulation. When the content of the heat-resistant synthetic resin precursor exceeds 45% by weight, the obtained heat-dissipating film may be inferior in heat resistance. A more preferred lower limit of the content of the heat-resistant synthetic resin precursor is 5% by weight, and a more preferred upper limit is 30% by weight.

As the dispersion medium, for example, a hydrocarbon solvent such as n-pentane, n-hexane, n-octane or n-decane, or methanol, ethanol, 1-propanol, 2-propanol, 1-butanol or 2- can be used. An alcohol solvent such as butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, ethylene glycol or propylene glycol, or acetone or methyl ethyl ketone a ketone solvent such as diethyl ketone, methyl isobutyl ketone or cyclohexanone, or N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl A guanamine solvent such as acrylamide or N-methyl-2-pyrrolidone, or diethyl ether, methyl tert-butyl ether, or An ether solvent such as an alkane, tetrahydrofuran or cyclopentyl methyl ether, or benzene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, toluene, o-xylene, p-xylene or ethylbenzene. A benzene-based solvent such as phenol, p-chlorophenol, o-chlorophenol or o-cresol, or a sulfur-containing solvent such as dimethyl hydrazine, dimethyl hydrazine or cyclobutyl hydrazine. Further, water may be used as the dispersion medium as long as the amount of the additive is not precipitated. Among them, in terms of improving the solubility of the heat-resistant synthetic resin, it is preferably selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylformamide, and N,N-di At least one of a group consisting of methyl acetamide, dimethyl hydrazine, tetrahydrofuran, and cyclobutyl hydrazine. These dispersion media may be used singly or in combination of two or more.

The content of the water-insoluble inorganic compound in the dispersion liquid for a heat radiation layer of the present invention is 30% by weight or less, and the upper limit is 90% by weight based on the total amount of the nonvolatile component. If the content of the water-insoluble inorganic compound is less than 30% by weight, the heat radiation layer of the obtained heat-dissipating film The flammability will become higher. When the content of the water-insoluble inorganic compound exceeds 90% by weight, the viscosity of the dispersion becomes high, and the thermal insulation layer is unevenly coated with the metal film, and the film thickness of the heat radiation layer is thinned to impair electrical insulation. The situation. A preferred lower limit of the content of the water-insoluble inorganic compound is 35% by weight, a preferred upper limit is 85% by weight, a still lower limit is 40% by weight, a still more preferred upper limit is 80% by weight, and a further preferred lower limit is 50% by weight. A preferred upper limit is 70% by weight, and a preferred lower limit is 60% by weight.

The content of the nonvolatile component in the dispersion liquid for a heat radiation layer of the present invention is more than 18% by weight and not more than 65% by weight. When the content of the non-volatile component is 18% by weight or less, the dispersion liquid for a heat radiation layer becomes uneven, and a uniform film cannot be obtained. When the content of the non-volatile component exceeds 65% by weight, the viscosity of the dispersion for the heat radiation layer is excessively increased, and it is difficult to form a film. The content of the above nonvolatile matter is preferably more than 20% by weight and not more than 55% by weight, more preferably more than 25% by weight and not more than 45% by weight.

Further, the ratio of the non-volatile components in the dispersion for the heat radiation layer of the present invention can be determined by thermogravimetry (TG), differential thermal-thermal weight simultaneous measurement (TG-DTA) or an evaporator, etc. by vacuum evaporation. The removal is obtained from the weight of the remaining solid matter.

The heat dissipating film of the present invention can be produced by a method having the following steps: step (1-1), dispersing a medium, a water-insoluble inorganic compound which is a nonvolatile matter, and a heat-resistant synthetic resin and/or a heat-resistant synthetic resin The mixture is mixed to prepare a dispersion for a heat radiation layer of the present invention; in step (1-2), the prepared heat radiation layer dispersion is extended on a metal film which becomes a heat transfer layer and allowed to stand; and the step (1) -3) The heat radiation layer extending from the metal film is removed by a dispersion liquid and molded to obtain a laminated film. The method of manufacturing such a heat-dissipating film is also one of the inventions.

Further, the heat-dissipating film of the present invention can be produced by a method having the following steps: step (2-1), dispersing a medium, a water-insoluble inorganic compound which is a nonvolatile component, and a heat-resistant synthetic resin and/or a heat-resistant synthetic resin. Dispersing the heat radiation layer of the present invention by mixing the precursors Liquid; step (2-2), the prepared heat radiation layer dispersion liquid is extended on the substrate and allowed to stand; step (2-3), the heat radiation layer extending from the substrate is removed by a dispersion liquid and removed Forming, and separating the obtained film from the substrate to obtain a film for a heat radiation layer; and step (2-4), the heat radiation layer is densely laminated to form a heat transfer film by heat pressing A metal film of the layer is obtained to obtain a laminated film. The method of manufacturing such a heat-dissipating film is also one of the inventions.

Hereinafter, the method having the steps (1-1) to (1-3) and the method having the steps (2-1) to (2-4) are collectively referred to as "the method for producing the heat-dissipating film of the present invention".

In the method for producing a heat-radiating film of the present invention, in the above step (1-1) or (2-1), a dispersion medium, a water-insoluble inorganic compound which is a nonvolatile component, a heat-resistant synthetic resin, and/or heat resistance are used. The synthetic resin precursor is mixed to prepare a dispersion for a heat radiation layer of the present invention.

The mixing temperature in the above step (1-1) or (2-1) is not particularly limited, and a preferred lower limit is 10 ° C, and a preferred upper limit is 40 ° C.

In the method for producing a heat-radiating film of the present invention, in the above step (1-2) or (2-2), the dispersion for a heat radiation layer of the present invention is stretched on a metal film or a substrate and allowed to stand.

In the above step (1-2) or (2-2), as a method of stretching the dispersion for a heat radiation layer of the present invention on a metal film or a substrate, a doctor blade or a bar coating may be used. A method of coating a film or the like into a film.

In the above step (2-2), as the substrate for stretching the dispersion, from the viewpoint of compatibility or wettability of the dispersion with the substrate and peelability after drying, it is preferably made of glass or polypyridyl acid. Made of diester, polyimine, polyethylene, or polypropylene.

In the above step (1-2) or (2-2), the dispersion for a heat radiation layer of the present invention which is stretched on a metal film or on a substrate preferably has a thickness of 30 μm or more. If the thickness of the dispersion for a heat radiation layer of the present invention is less than 30 μm, the heat radiation layer of the obtained heat dissipation film becomes thin and the electrical insulation property is impaired. The thickness of the dispersion for the heat radiation layer of the present invention is preferably lower It is 50 μm, and a preferred lower limit is 100 μm.

In the method for producing a heat-radiating film of the present invention, in the above step (1-3) or (2-3), the dispersion medium is removed from the heat radiation layer dispersion which is stretched on the metal film or on the substrate. In the above step (1-3), the laminated film is obtained by removing and shaping the dispersion medium. Further, in the above step (2-3), the film for heat radiation layer is obtained by removing and molding the dispersion medium, and separating the obtained film from the substrate.

In the above step (1-3) or (2-3), as a method of removing the dispersion medium from the dispersion for the heat radiation layer extended on the metal film or on the substrate, various solid-liquid separation methods such as centrifugal separation may be used. , filtration, vacuum drying, freeze vacuum drying, heated evaporation, or a combination of these methods. In these methods, for example, when the heating evaporation method is used, the dispersion liquid applied to the metal film or the substrate can be maintained at a level of 20 to 150 ° C by using a forced air oven. Preferably, it is dried at a temperature of 30 to 120 ° C for about 0.5 to 24 hours, preferably for 2 to 12 hours, and the dispersion medium is removed.

In the above step (2-4), the film for a heat radiation layer obtained in the above step (2-3) is adhered to a metal film which becomes a heat transfer layer by hot pressing to obtain a laminated film. .

In the above step (2-4), from the viewpoint of improving the adhesion of the heat radiation layer to the metal film, it is preferable that the heat radiation layer film is laminated to the metal film at a hot pressing temperature of 50 to 200 ° C. The pressure is 10~100kgf/cm ² . The above hot pressing temperature is more preferably 100 to 150 ° C or less.

When the heat-resistant synthetic resin precursor is blended in the dispersion for a heat radiation layer of the present invention, the laminated film obtained in the above step (1-3) or (2-4) can be further heated by using an electric furnace or the like. The heat-dissipating film of the present invention is obtained in steps. Specifically, for example, when a polyamine acid is blended as a precursor of a heat-resistant synthetic resin, a laminated film is obtained, and then heat treatment is performed at 120 to 400 ° C for 0.5 to 10 hours, whereby the heat radiation layer can be obtained. Polyimine is used as a heat-dissipating film of a heat-resistant synthetic resin.

The heat dissipating film of the present invention has high mechanical strength due to heat dissipation and radiation heat dissipation, electrical insulation, and flexibility, and is therefore suitable for discharging heat generated by an IC chip or LED built in an electronic device. .

A solar cell using the heat dissipation film of the present invention is also one of the inventions.

Since the heat-dissipating film of the present invention is excellent in moisture resistance, heat dissipation, and electrical insulation, and has high mechanical strength, the solar cell of the present invention using the heat-dissipating film of the present invention is excellent in durability and weather resistance.

A schematic cross-sectional view showing an example of a solar cell of the present invention is shown in Fig. 1.

As shown in FIG. 1, the solar cell 1 of the present invention has a solar cell element 2 that converts light energy into electric energy by a photoelectromotive force, and the solar cell element 2 is sealed by a sealant 3. Further, the solar cell 1 of the present invention has a light-transmitting substrate 4 on the surface on the side receiving the sunlight, and has a heat-dissipating film of the present invention on the surface opposite to the light-transmitting substrate 4 (the laminated heat transfer layer 5 and the heat radiation layer 6) a laminated film).

The solar cell element 2 is not particularly limited as long as it can convert light energy into electric energy by photoelectromotive force, and for example, single crystal germanium, polycrystalline germanium, amorphous germanium, or compound semiconductor (3-5 families, 2-6, etc.), etc., among them, polycrystalline germanium is preferred.

The sealant 3 may, for example, be a sealant comprising an ethylene-vinyl acetate copolymer, an ethylene-aliphatic unsaturated carboxylic acid copolymer, an ethylene-aliphatic carboxylic acid ester copolymer, or a saponified product thereof. .

The light-transmitting substrate 4 is located on the outermost layer of the solar cell 1 on the sunlight receiving side. Therefore, it is preferably excellent in weather resistance, water repellency, antifouling property, mechanical strength, and the like in addition to transparency.

The material of the light-transmitting substrate 4 is a resin substrate made of a polyester resin, a fluororesin, an acrylic resin, an ethylene-vinyl acetate copolymer, or the like, or a glass substrate. And in terms of being excellent in impact resistance and being inexpensively produced, it is preferably glass substrate. Further, in particular, in terms of excellent weather resistance, a fluororesin can also be preferably used.

The method for producing the solar cell 1 of the present invention is not particularly limited, and examples thereof include sequentially laminating the light-transmitting substrate 4, the sealant 3 in which the solar cell element 2 is sealed, and the heat-dissipating film of the present invention, and performing vacuum lamination. Method and so on.

According to the present invention, it is possible to provide a heat-dissipating film having high mechanical strength and flexibility, which is excellent in heat dissipation, electrical insulation, and heat resistance by infrared radiation on a metal film excellent in heat conductivity. Thermal radiation layer. Moreover, according to the present invention, a dispersion liquid for a heat radiation layer for producing the heat dissipation film, a method for producing a heat dissipation film using the dispersion liquid for the heat radiation layer, and a solar battery using the heat dissipation film can be provided.

1‧‧‧Solar battery

2‧‧‧Solar battery components

3‧‧‧Sealant

4‧‧‧Transmissive substrate

5‧‧‧heat transfer layer

6‧‧‧thermal radiation layer

Fig. 1 is a schematic cross-sectional view showing an example of a solar cell of the present invention.

Fig. 2 is a photograph of (a) the front side and (b) the back side of the solar cell fabricated using the heat-dissipating film produced in the examples.

Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited to the examples.

(Example 1)

(Synthesis of polyamic acid varnish)

4,4-diaminodiphenyl ether 140.1 g (0.70 mol) and N-methyl-2-pyrrolidone 1433.3 g were added to a reaction vessel equipped with a 2 L capacity of a stirrer and a thermometer at 30 to 40 ° C. Dissolve. Then, while maintaining the temperature at 45 to 50 ° C, pyromellitic dianhydride 72.5 g (0.33 mol), 3,3', 4,4'-biphenyl was added to the reaction vessel over 40 minutes. Tetracarboxylic dianhydride 97.8 g (0.33 mol). After stirring at the same temperature for 60 minutes, add 2.4 18% by weight of a solution of pyromellitic dianhydride in N-methyl-2-pyrrolidone (0.02 mol) to adjust the viscosity, adding 4.2% by weight of N-methyl-2-phthalic anhydride The pyrrolidone solution was 7.5 g (0.002 mol) to stop the reaction, and 1933.9 g of a polyamic acid varnish having a concentration of 16.3% and a viscosity of 6.2 Pa·s was obtained.

(Preparation of dispersion for heat radiation layer)

6.0 g of talc ("TALC RA" manufactured by NIPPON TALC Co., Ltd.) and 24.5 g of polyamic acid varnish (polyglycolic acid 4.0 g, N-methyl-2-pyrrolidone 20.5 g) were placed. The plastic-made closed container was stirred in a mixing mode (2000 rpm) for 10 minutes and a defoaming mode (2200 rpm) for 10 minutes using a rotation and rotation stirrer ("ARE-310" manufactured by Thinky Co., Ltd.) to obtain a talc with respect to the nonvolatile matter. The ratio was 60.0% by weight, and the ratio of the nonvolatile matter to the entire dispersion was 32.8% by weight of a uniform dispersion for a heat radiation layer.

(production of heat dissipation film)

The obtained heat radiation layer dispersion liquid was applied to an aluminum film having a flat bottom surface and a rectangular bottom shape having a thickness of 200 μm using a bar coater having a groove depth of 200 μm. The film for a heat radiation layer was formed on the aluminum film in a forced air oven at a temperature of 90 ° C for 2 hours while maintaining the aluminum level. The laminated film was sequentially subjected to heat treatment at 120 ° C for 30 minutes, at 150 ° C for 5 minutes, at 200 ° C for 5 minutes, at 250 ° C for 5 minutes, and at 350 ° C for 60 minutes to obtain a heat radiation layer having a thickness of 49.2 μm. The heat radiation film is composed of talc and a polyimide resin, and the content of the water-insoluble inorganic compound (talc) relative to the entire heat radiation layer is 60.0% by weight.

(Example 2)

In the "(Preparation of dispersion for heat radiation layer)", the amount of talc is 36.0 g, and 22.8 g of N-methyl-2-pyrrolidone is further added, and otherwise, In the same manner, a dispersion liquid of a uniform heat radiation layer having a ratio of talc to the entire nonvolatile component of 90.0% by weight and a ratio of the nonvolatile component to the entire dispersion liquid of 48.0% by weight was obtained.

A heat-dissipating film having a heat radiation layer having a thickness of 57.6 μm was obtained in the same manner as in Example 1 except that the obtained dispersion for a heat radiation layer was used, using a bar coater having a groove depth of 100 μm. The layer was composed of talc and a polyimide resin, and the content of the water-insoluble inorganic compound (talc) relative to the entire heat radiation layer was 90.0% by weight.

(Example 3)

In the same manner as in Example 1, except that the amount of the talc was 1.7 g, the ratio of the total talc to the nonvolatile component was 30.0 in the same manner as in Example 1 except that the ratio of the talc to the total amount of the talc was 30.0. The weight % and the ratio of the nonvolatile matter to the entire dispersion were 21.8% by weight of a uniform dispersion for a heat radiation layer.

The dispersion for the heat radiation layer obtained was applied by using a bar coater having a depth of 200 μm, and dried in a forced air oven at 90 ° C for 30 minutes to remove the dispersion medium, and then, the coating was further applied thereto. A heat-dissipating film having a heat radiating layer having a thickness of 43.6 μm was obtained in the same manner as in Example 1 except that the coating surface was coated with a bar coater having a groove depth of 150 μm, and the heat radiating layer was composed of talc and The content of the water-insoluble inorganic compound (talc) relative to the entire heat radiation layer was 30.0% by weight.

(Example 4)

Talc (manufactured by NIPPON TALC, "TALC RA") 3.0 g, coal ash ("Sean Environment Service", "Clean-ash") 3.0 g, carbon black (manufactured by Mitsubishi Chemical Corporation, "MA-100") 0.2 g 24.5 g (polyglycolic acid 4.0 g, N-methyl-2-pyrrolidone 20.5 g) synthesized in Example 1 was placed in a plastic sealed container to be in the same manner as in Example 1 (Preparation of dispersion for heat radiation layer)" The mixture was stirred and mixed in the same manner, and the total ratio of talc, coal ash, and color former (carbon black) to the nonvolatile component was 60.8 wt%, and the nonvolatile matter was relative to The ratio of the entire dispersion was 33.2% by weight of a uniform dispersion for a heat radiation layer.

Using the obtained dispersion for a heat radiation layer, in the same manner as in Example 1, a heat dissipating film of a thermal radiation layer having a thickness of 49.2 μm, the heat radiating layer being composed of talc, coal ash, carbon black, and a polyimide resin, and the total of talc, coal ash, and coloring agent (carbon black) is relative to the heat radiating layer as a whole. The content was 60.8% by weight.

(Example 5)

6.0 g of non-swelling mica (manufactured by Yamaguchi Mica Co., Ltd., "SJ-010"), and 24.5 g of polyamic acid varnish synthesized in Example 1 (polyglycine 4.0 g, N-methyl-2-pyrrole) 20.5 g of ketone was placed in a sealed container made of plastic, and 2.8 g of N-methyl-2-pyrrolidone was added thereto in the same manner as in "Preparation of dispersion for heat radiation layer" of Example 1. The mixture was stirred and mixed to obtain a uniform dispersion for a heat radiation layer in which the ratio of the water-insoluble inorganic compound to the entire nonvolatile component was 60.0% by weight and the ratio of the nonvolatile component to the entire dispersion was 30.0% by weight.

Using the obtained dispersion for a heat radiation layer, a heat dissipation film having a heat radiation layer having a thickness of 45.0 μm was obtained in the same manner as in Example 1, and the heat radiation layer was composed of non-swelling mica and a polyimide resin, and was insoluble in water. The content of the inorganic compound (non-swellable mica) with respect to the entire heat radiation layer was 60.0% by weight.

(Comparative Example 1)

Talc (manufactured by NIPPON TALC Co., Ltd., "TALC RA") 6.0 g, in which the ratio of the talc to the non-volatile component was 60.0% by weight, and the ratio of the non-volatile component to the entire dispersion was 18.0% by weight. 24.5g of polyamic acid varnish synthesized in 1 (polyglycolic acid 4.0g, N-methyl-2-pyrrolidone 20.5g), and N-methyl-2-pyrrolidone 25.1g in plastic The sealed container was stirred and mixed in the same manner as in "Preparation of the dispersion for heat radiation layer" of Example 1, but the talc was precipitated after standing for several minutes, and a uniform dispersion was not obtained.

Further, in the same manner as in Example 1, the production of the film was attempted, but the talc was precipitated, and a uniform film was not obtained.

(Comparative Example 2)

24.5 g (polyglycolic acid 4.0 g, N-methyl-2-pyrrolidone 20.5 g) synthesized in Example 1 was placed in a plastic closed container and placed in an oven at 90 ° C. The solvent was evaporated until the total amount became 10.8 g to prepare a 37.0% by weight solution of polyglycine N-methyl-2-pyrrolidone (polyglycine 4.0 g, N-methyl-2-pyrrole). Pyridone 6.8g). 9.3 g of talc ("TALC MS-K", manufactured by NIPPON TALC Co., Ltd.) was added thereto, and stirred and mixed in the same manner as in "Preparation of dispersion for heat radiation layer" of Example 1 to obtain a water-insoluble inorganic compound. (The talc) is a dispersion liquid for a uniform heat radiation layer having a content of 70.0% by weight based on the entire nonvolatile component and a ratio of the nonvolatile component to the entire dispersion liquid of 66.2% by weight.

The obtained heat radiation layer dispersion had almost no fluidity, so that it could not be coated, and a heat dissipation film could not be produced.

(Comparative Example 3)

(Synthesis of polyamic acid varnish)

Add 3,3',4,4'-biphenyltetracarboxylic dianhydride 29.4 g (0.10 mol) and N,N-dimethylacetamide 80.8 g to a reaction vessel of 500 mL capacity equipped with a stirrer and a thermometer. And dissolved at room temperature. Then, it was cooled to 0 ° C, and 2,4-diaminodicyclohexylmethane 21.0 g (0.10 mol) and N,N-dimethylacetamide 37.0 g were added at 0 to 25 ° C for 2 hours. Founder. Thereafter, the mixture was stirred at room temperature for 1 week, and 0.7 g (0.0002 mol) of a N,N-dimethylacetamide solution of 4.2% by weight of phthalic anhydride was added to stop the reaction, thereby obtaining a concentration of 29.8%, viscosity. 10Pa‧s polyglycolic acid varnish 168.9g.

(production of heat dissipation film)

30.7 g (9.1 g of polyamidamine and 21.6 g of N-methyl-2-pyrrolidone) of the synthesized polyamic acid varnish were placed in a plastic closed container, and a defoaming mode was performed for 10 minutes using a rotary revolution mixer ( Defoaming was carried out at 2200 rpm). Then, the polyacetate varnish was applied in a thickness of 250 μm using a doctor blade, and the water-insoluble property was obtained in the same manner as in the "preparation of the dispersion for heat radiation layer" of Example 1. Thermal radiation layer of inorganic compound having a thickness of 65.2 μm Heat sink film.

(Comparative Example 4)

3.0 g of talc ("TALC RA" manufactured by NIPPON TALC Co., Ltd.), 3.0 g of coal ash ("Clean-ash" manufactured by Soma Environment Service), 2.0 g of carbon black, and polylysine synthesized in Example 1. 24.5 g of varnish (4.0 g of polyamidetic acid, 20.5 g of N-methyl-2-pyrrolidone) and 4.5 g of NMP were placed in a sealed container made of plastic, and stirred and mixed in the same manner as in Example 1 to obtain The ratio of the water-insoluble inorganic compound (talc + coal ash) to the coloring agent (carbon black) to all non-volatile components is 66.7 wt%, and the ratio of the non-volatile component to the total amount of the dispersion is 32.4 wt%. A dispersion for the radiation layer.

Using the obtained dispersion for a heat radiation layer, in the same manner as in Example 1, a heat dissipation film having a heat radiation layer having a thickness of 48.6 μm was obtained, which was composed of talc and a polyimide resin, and a water-insoluble inorganic compound ( The ratio of talc + coal ash to coloring agent (carbon black) to total weight was 66.7 wt%.

(Comparative Example 5)

A liquid Cerac α (manufactured by Ceramission Co., Ltd.) containing a mixture of cerium oxide or aluminum oxide and a polyoxyxylene resin as a binder was applied to the bottom surface of the heat transfer layer to a thickness of 50 μm by a bar coater. The shape of the flat surface and the bottom surface is a rectangular aluminum film having a thickness of 200 μm. While maintaining the aluminum level, it was dried in a forced air oven at a temperature of 90 ° C for 1 hour to form a heat radiation layer on the aluminum. The laminated film was heat-treated at 120 ° C for 20 minutes to obtain a heat-dissipating film having a heat radiating layer having a thickness of 50.0 μm, which was composed of a mixture of cerium oxide or aluminum oxide and a polyfluorene-based resin, and a water-insoluble inorganic compound (oxidized) The content of the mixture of cerium and alumina) relative to the entire heat radiating layer was 56.0% by weight.

(Comparative Example 6)

In the "(Production of heat-dissipating film)", a graphite sheet having a thickness of 135 μm (manufactured by Japan Matex Co., Ltd.) was used as the heat transfer layer instead of the aluminum film having a thickness of 200 μm, and the same as Example 1 In the same manner, a heat-dissipating film having a heat radiation layer having a thickness of 49.2 μm was obtained, which was composed of talc and a polyimide resin, and the content of the water-insoluble inorganic compound (talc) relative to the entire heat radiation layer was 60.0% by weight.

The ratio of the composition of the dispersion for the heat radiation layer prepared in Examples 1 to 5 and Comparative Examples 1 to 4, the ratio of the nonvolatile matter to the entire dispersion liquid, and the ratio of the water-insoluble inorganic compound to the total nonvolatile matter In Table 5.

<evaluation>

The following evaluations were performed on the heat-dissipating films obtained in the examples and the comparative examples. The evaluation of the heat radiation rate, the dielectric breakdown strength, the adhesion, and the flammability was performed only by forming the heat radiation layer of the heat dissipation film.

In addition, in Comparative Example 1 and Comparative Example 2 in which the heat dissipation film was not produced, the following evaluations were not performed.

The results are shown in Table 6.

(thermal radiance)

The heat emissivity was measured using a thermal emissivity meter "TSS-5X" manufactured by Japan Sensor.

(insulation breaking strength)

The dielectric breakdown voltage (kV) was measured using an insulation breakdown tester "HAT-300 type" manufactured by Hitachi Chemical Co., Ltd. according to the method of ASTM D149, and the dielectric breakdown strength (kV/mm) was calculated.

(adhesion)

For the heat radiation layer of the obtained heat dissipation film, a cross-cut test according to JIS K5600 was conducted. Use a single-sided cutting tool to cut a rectangular pattern (25 grids) of the heat radiation layer, paste the transparent tape on the grid pattern, and pull it at an angle of approximately 60 ° C for 0.5 to 1.0 seconds. The degree of peeling of part of the heat radiation layer was set to 0 with the minimum degree of peeling, and according to Table 1, it was visually classified into 6 levels of 0 to 5.

(by the flammability classification of the VTM test)

For the heat radiation layer of the obtained heat dissipation film, a thin material vertical burning test (VTM test) according to the UL94 standard was performed.

In each of the determination criteria shown in Table 2, five test pieces (a length of about 200 mm and a width of 50 mm) were used. Set the size of the flame to 20mm.

Further, the time of contact with the flame was set to 3 seconds, and the residual flame time after the contact with the flame was measured. At the same time as the fire was extinguished, the second contact was performed for 3 seconds, and the afterflame time after the contact with the flame was measured in the same manner as in the first time. Further, whether or not the cotton fire under the test piece was fired was also evaluated at the same time as to whether or not the fire was dropped. Moreover, the marking line is located at a position 125 mm from the lower end of the test piece, and the marking cotton is disposed below the lower end of the test piece by 300 mm.

In the VTM test, as the flammability classification, VTM-0 was the highest, indicating that the flame retardancy was lowered by VTM-1 and VTM-2. Among them, those who do not meet any of the VTM-0~VTM-2 levels are considered as unqualified.

(by the flammability classification of the V test)

For the heat radiation layer of the obtained heat dissipation film, a vertical burning test (V test) according to the UL94 standard was performed.

In each of the determination criteria shown in Table 3, five test pieces (length 127 mm, width 13 mm) were used. Set the size of the flame to 20mm.

Further, the time of contact with the flame was set to 10 seconds, and the residual flame time after the contact was measured.

Further, at the same time as the fire was extinguished, the second contact was performed for 10 seconds, and the afterflame time after the contact with the flame was measured in the same manner as in the first time. Further, whether or not the cotton fire under the test piece was fired was also evaluated at the same time as to whether or not the fire was dropped.

From the first and second burning times, and the presence or absence of the ignition of the cotton, the classification of the flammability is determined in accordance with the UL-94V standard. In the V test, as the flammability classification, V-0 was the highest, indicating that the flame retardancy was lowered by V-1 and V-2. Among them, those who do not meet any of the levels of V-0 to V-2 are set as unqualified.

(by the flammability classification of the 5V test)

For the heat radiation layer of the obtained heat dissipation film, a 125 mm vertical burning test (5 V test) according to the UL94 standard was performed.

For each of the criteria shown in Table 4, a test piece (length 127 mm, width 13 mm) was used. Set the size of the flame to 125mm.

Further, the time of contact with the flame was set to 5 seconds, and the residual flame time after the contact with the flame was measured.

Further, at the same time as the fire was extinguished, the second contact was performed for 5 seconds, and the afterflame time after the contact with the flame was measured in the same manner as in the first time. Repeat it 5 times. Further, whether or not the cotton fire under the test piece was fired was also evaluated at the same time as to whether or not the fire was dropped.

From the first to the fifth burning time, and the presence or absence of the ignition of the cotton, the classification of the flammability is determined according to the UL-94 and 5V standards. For those who passed the above, a flat burning test was further carried out.

In the evaluation of the flat burning test, a flat test piece (length 150 mm, width 150 mm) was used. Set the size of the flame to 125mm.

Further, the time for contacting the flame was set to 5 seconds, and the second contact was performed for 5 seconds while the fire was extinguished, and this was repeated 5 times. Confirm the presence or absence of perforation of the flat test piece after contact with the flame. For the non-perforated person, the evaluation was 5 V-A, and for the confirmed perforation, the evaluation was 5 V-B.

(cooling performance)

For the obtained heat-dissipating film, the cooling performance was evaluated by the following method.

In a plastic sealed container (body: polypropylene, cover: polyethylene, container size 188mm × 225mm, distance from ceramic heater to cover 18mm), placed on the substrate (Model manufactured by Sunhayato, "MODEL ICB-88G" ") A ceramic heater ("BPC10" manufactured by BI Technologies Japan Co., Ltd., 2.4 cm square) having a thickness of 0.5 to 1.5 mm (hereinafter also referred to as "heater"). A DC stabilized power supply ("AD-8724D" manufactured by A&D Co., Ltd.) was connected to the heater by welding the covered electric wire to the end of the heater. In the heating point portion of the heater (12 mm × 19 mm), in order to avoid contact between the welded portion and the heat-dissipating film, an aluminum film (thickness: 1 mm) having the same area as that of the heat-dissipating film is provided, and foamed styrene is disposed in the lower portion of the sealed container. Insulation materials.

In this state, the output current of the DC stabilized power supply is adjusted, and 3 W of electric power is input to the heater, and the temperature (heating temperature (A)) at the time of equilibrium is measured by the data recorder. Then, a flat-shaped heat dissipating film of 2.4 cm square was placed in the same heater as when the heating temperature (A) was measured. Above, and measure the temperature at the equilibrium state (the temperature (B) of the film is set). Further, when a heat dissipating film is provided, a polysulfide grease ("SCH-20" manufactured by Sunhayato Co., Ltd.) is applied to a heater in an appropriate amount to adhere the heater to the heat dissipating film. The temperature difference (A-B) between the heat generation temperature (A) and the temperature (B) at which the film was provided was evaluated as the cooling performance.

Further, an aluminum film having a thickness of 200 μm was used instead of the heat dissipation film, and the same operation was performed to evaluate the cooling performance.

(bending resistance)

With respect to the obtained heat-dissipating film, the bending resistance (cylindrical mandrel method) test was carried out by the method according to JIS K5600-5-1. The test method uses a mandrel of 1~10 mm diameter, and tests a test piece from a larger diameter mandrel to a smaller mandrel, and indicates a mandrel diameter at which the heat radiation layer of the heat dissipation film starts to generate cracks. . The evaluation of the heat radiation layer which did not cause cracks even with a mandrel of 1 mm was set to 1 mm or less.

(Tensile Strength)

For the obtained heat-dissipating film, test piece type 5 was produced in accordance with JIS K7127-1, and a table-top precision universal testing machine ("AGS-X" manufactured by Shimadzu Corporation) was used, and the chuck was spaced 80 mm apart and the stretching speed was 5 mm. The tensile test was carried out under the conditions of /min, and the maximum tensile strength was measured to determine the tensile strength (N/mm ² ).

(water vapor transmission)

For the obtained heat-dissipating film, a gas-vapor permeability measuring device manufactured by GTR-TEC Co., Ltd. was used at 40 ° C, 90% by differential pressure gas chromatography in accordance with JIS K-7126A (differential pressure method). The measurement of the water vapor transmission rate was carried out under the conditions of RH.

(Production and performance evaluation of solar cells)

A solar cell unit was fabricated by soldering two 156 mm square c-Si2 strings by soldering a label line of 6 mm width at 340 °C. A sealing material EVA sheet ("Sunvic FC", 40 cm square) manufactured by Sunvic Co., Ltd. was placed on a glass plate (manufactured by Asahi Glass Co., Ltd., 40 cm square), and a solar battery unit was placed thereon. Two sheets of the EVA sheet as the sealing material were placed on the unit with the transparent Tedlar of the same area as the solar cell unit. Finally, the film prepared in Example 4 was placed, and the mounting terminal was passed through the slit portion. The vacuum laminator was thermocompression bonded at 135 ° C for 21 minutes. The EVA which protruded from the end of the thermocompression bonding plate was peeled off by a heat cutter, and the sealant (manufactured by Yokohama Rubber Co., Ltd., "HAMATITE HOT MELT M-155") was heated to be filled in a molten state to the aluminum frame. In the groove, and embedded in the four sides of the laminate, the four corners of the aluminum frame are screwed and naturally dried at room temperature. After drying, a terminal block (manufactured by Onamba Co., Ltd.) was attached to the heat-dissipating film so as to cover the terminal portion by using a sealant ("SH780 Sealant" manufactured by Dow Corning Toray Co., Ltd.), and it was naturally dried at room temperature, and the terminal was mounted at 340. °C soldered to the terminal box. Thereafter, 30 g of a potting agent ("PV-7321" manufactured by Dow Corning Toray Co., Ltd.) (mixing the base and the hardener in a ratio of 10:1) was poured into the terminal box and allowed to dry naturally. After standing for about 1 week, the cover of the terminal box was mounted to make a finished product of the solar cell. Photographs of (a) front side and (b) back side of the fabricated solar cell are shown in Fig. 2.

The performance of the obtained solar cell was evaluated. As a result, in the I-V characteristic evaluation, the fill factor value was 0.65 to 0.75, and it was confirmed that it had normal output performance as a solar cell.

[Industrial availability]

According to the present invention, it is possible to provide a heat-dissipating film having high mechanical strength and flexibility, which is excellent in heat conductivity by laminating heat radiation having excellent heat dissipation, electrical insulation, and heat resistance by infrared radiation. Made of metal film. Further, according to the present invention, it is possible to provide a dispersion for a heat radiation layer for producing the heat dissipation film, and a dispersion for using the dispersion for the heat radiation layer A method of producing a hot film and a solar cell using the heat dissipating film.

Claims (27)

A heat dissipating film having a heat transfer layer and a flexible heat radiating layer laminated on the heat transfer layer, wherein the heat transfer layer is a metal film containing a water-insoluble inorganic compound and heat-resistant synthetic In the resin, the content of the water-insoluble inorganic compound in the heat radiation layer is 30 to 90% by weight based on the entire heat radiation layer, the heat radiation rate of the heat radiation layer is 0.8 or more, and the dielectric breakdown strength is 10 kV/mm or more. . The heat-dissipating film of claim 1, wherein the heat radiation layer is laminated on one side of the heat transfer layer, and the other layer of the heat transfer layer has an insulating layer containing a water-insoluble inorganic compound and a heat-resistant synthetic resin. The content of the water-insoluble inorganic compound in the insulating layer is 30 to 90% by weight based on the entire insulating layer. The heat-dissipating film according to claim 1 or 2, wherein the water-insoluble inorganic compound contains a compound selected from the group consisting of a cerium oxide compound, a silica-alumina compound, an aluminum compound, a calcium compound, a nitride, and coal ash. At least one of the groups. The heat-dissipating film of claim 1, 2 or 3, which comprises a layered silicate mineral as a water-insoluble inorganic compound. The heat-dissipating film of claim 4, wherein the layered silicate mineral is a non-swelling clay mineral. The heat-dissipating film of claim 5, wherein the non-swelling clay mineral is at least one selected from the group consisting of talc, kaolin, pyrophyllite, and non-swelling mica. The heat-dissipating film of claim 1, 2, 3, 4, 5 or 6 wherein the heat-resistant synthetic resin is a polyimide resin or a polyimide imide resin. The heat-dissipating film of the first, second, third, fourth, fifth, sixth or seventh aspect of the patent application, wherein the heat radiation layer is adhered to the metal film used as the heat transfer layer in the cross-cut test according to JIS K5600 The sex classification is 0~2. For example, the heat-dissipating film of the first, second, third, fourth, fifth, sixth, seventh or eighth item of the patent application, wherein the heat radiation layer is classified as VTM-0 in the UL94 standard VTM test, and the flammability classification is VTM. The thickness of the heat radiation layer at -0 is 100 μm or less. For example, in the heat-dissipating film of claim 1, 2, 3, 4, 5, 6, 7, 8, or 9, wherein the thickness of the heat radiating layer is 20 to 100 μm. The heat-dissipating film of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the metal film used as the heat transfer layer is an aluminum film or a copper film. The heat-dissipating film of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 wherein the heat transfer layer has a thickness of 10 to 1000 μm. For example, the heat-dissipating film of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh or eleventh aspect of the patent application, wherein the heat is 2.4cm square and the thickness is 0.5~ when inputting 3W electric power. When the upper surface of the 1.5 mm ceramic heater is provided with a heat dissipating film in the same area as the ceramic heater, the cooling temperature is 15 ° C or higher. For example, the heat-dissipating film of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, thirteenth or thirteenth or thirteenth patent application, which is borrowed according to JIS K5600-5-1 (1999) In the bending resistance test by the cylindrical mandrel method, when the heat radiation layer of the heat dissipation film is broken, the mandrel diameter is 10 mm or less. For example, the heat-dissipating film of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, thirteenth, thirteenth or thirteenthth aspect of the patent application, wherein the water vapor is in an environment of 40 ° C and 90% RH The transmittance is less than 0.01g/m ² ‧day. A heat radiation layer dispersion for producing a heat dissipation film of the claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 The dispersion for a heat radiation layer contains a dispersion medium, a water-insoluble inorganic compound which is a nonvolatile component, and a heat-resistant synthetic resin and/or a heat-resistant synthetic resin precursor, and the content of the water-insoluble inorganic compound is relative to the entire non-volatile component. 30~90 weight The content of the non-volatile component is more than 18% by weight and not more than 65% by weight based on the total amount of the dispersion liquid for the heat radiation layer. The dispersion for a heat radiation layer according to claim 16, wherein the dispersion medium is selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethyl At least one of the group consisting of acetamide, dimethyl hydrazine, tetrahydrofuran, and cyclobutyl hydrazine. A method for producing a heat-dissipating film, comprising the following steps (1-1) to (1-3), step (1-1): dispersing a medium, a water-insoluble inorganic compound which is a non-volatile component, and a heat-resistant synthetic resin and/or Or the heat-resistant synthetic resin precursor is mixed to prepare the dispersion for the heat radiation layer of claim 16 or 17; and the step (1-2): the prepared heat radiation layer dispersion is extended to become the heat transfer layer The metal film is allowed to stand still; and the step (1-3): the heat radiation layer extending from the metal film is removed by a dispersion liquid and shaped to obtain a laminated film. The method for producing a heat-dissipating film according to claim 18, wherein in the step (1-2), the thickness of the dispersion extending on the metal film is 30 μm or more. The method for producing a heat-dissipating film according to claim 18 or 19, wherein in the step (1-3), the temperature at which the dispersion medium is removed from the heat radiation layer dispersion is 20 to 150 °C. A method for producing a heat-dissipating film, comprising the following steps (2-1) to (2-4), and step (2-1): dispersing a medium, a water-insoluble inorganic compound which is a non-volatile component, and a heat-resistant synthetic resin and/or Or the heat-resistant synthetic resin precursor is mixed to prepare the dispersion for the heat radiation layer of claim 16 or 17; and the step (2-2): the prepared heat radiation layer dispersion is extended on the substrate and static Step (2-3): removing the dispersion medium from the heat radiation layer stretched on the substrate and forming the film, and separating the obtained film from the substrate to obtain a film for the heat radiation layer; and 2-4): the heat radiation layer is laminated with a film by heat pressing to form a heat transfer layer A metal film is obtained to obtain a laminated film. The method for producing a heat-dissipating film according to claim 21, wherein in the step (2-2), the thickness of the dispersion extending on the substrate is 30 μm or more. The method for manufacturing a heat-dissipating film according to claim 21 or 22, wherein in the step (2-2), the substrate is made of glass, polyethylene terephthalate, polyimide, polyethylene, or polypropylene. Composition. The method for producing a heat-dissipating film according to claim 21, 22 or 23, wherein in the step (2-3), the temperature at which the dispersion medium is removed from the heat radiation layer dispersion is 20 to 150 °C. The method for producing a heat-dissipating film according to claim 21, 22, 23 or 24, wherein in the step (2-4), the heat-pressing temperature of the film for the heat radiation layer is tightly laminated to the metal film to 50 ~200 ° C, the pressure is 10 ~ 100kgf / cm ² . For example, the heat-dissipating film of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, thirteenth, thirteenth, thirteenth or thirteenth or fifteenth of the patent application is used for discharging the IC built in the electronic device. The heat generated by the wafer, or LED. A solar cell is formed by using a heat dissipating film of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, thirteenth, thirteenth, thirteenth or thirteenthth aspect of the patent application.