KR102098829B1 - A carbon seat having high heat-radiation property and manufacturing method thereof - Google Patents

Abstract

The high heat dissipation carbon sheet according to the present invention orients the fibrous thermal conductor present in the adhesive layer in the thickness direction of the adhesive layer, so that the fibrous thermal conductor acts as a channel connecting the heat generating part and the outside to effectively adhere the heat of the heating component. It can diffuse to the top of the layer. In addition, by further including at least one dispersing aid to increase the dispersibility of the fibrous thermal conductor having poor dispersibility in the polymer, the fibrous thermal conductor in the adhesive layer can be evenly dispersed and the orientation can be further increased.
The high heat dissipation carbon sheet according to the present invention can further improve the lifespan of components and devices due to the above-described characteristics, and solve the feeling of rejection of heat generated by consumers directly contacting portable electronic devices such as mobile devices. In addition, it is possible to significantly reduce the process cost and mass production cost compared to the existing simple lamination or graphene-based technology.

Description

A carbon seat having high heat-radiation property and manufacturing method thereof

The present invention relates to a high heat dissipation carbon sheet and a method for manufacturing the same, in detail, in manufacturing a high heat dissipation carbon sheet, a fibrous heat conductor and a filler are dispersed in an adhesive layer, of which the fibrous heat conductor is in the thickness direction of the adhesive layer. It relates to a high heat dissipation carbon sheet that can effectively diffuse the heat of the heat generating portion by orientation and a method for manufacturing the same.

Recently, electronic devices used in automobiles, electric and electronic fields, etc., are being sought to be lighter, thinner, smaller, and more versatile. The higher the integration of these electronic devices, the more heat is generated, and this heat of emission not only degrades the function of the device, but also causes malfunction of peripheral devices and deterioration of the substrate. Is being made. In particular, the high heat dissipation circuit board material is able to use the thermal conductivity of the base metal substrate, which is advantageous for the production of high power consuming and heat generating parts such as power devices and LED modules, and thus interest in research and development is amplifying. For example, about 85% of LEDs are converted into losses, and the temperature of the junction continues to increase due to the high temperature of heat emitted, leading to a decrease in the life of the LED semiconductor. It is known that the average time for malfunctions is reduced by a factor of 2 when the device operating temperature rises by 10 ° C. In order to prevent this, high power LEDs use high heat dissipation substrates, and accordingly, demand for high heat dissipation materials is rapidly increasing.

When looking at the material composition of the heat dissipation material, most of the composite material is a mixture of a high thermal conductivity filler material such as a carbon material or a ceramic material and a polymer material. Among them, the material used as a thermally conductive inorganic particle filler is a metal material having electrical conductivity such as graphite, carbon nanotubes, carbon-based materials such as graphene, silver and copper, and alumina, silica, aluminum nitride and boron nitride. It is classified as an electrically insulating material. However, there is a problem that there is a limit to sufficiently dissipating heat generated from electronic components and devices by simply dispersing the inorganic particle filler in a matrix made of a polymer resin.

Accordingly, various methods have been proposed to impart high thermal conductivity in the thickness direction of the heat dissipation member. For example, as an attempt to impart high thermal conductivity to the thickness direction of the heat conductive sheet, carbon is disclosed in Japanese Patent Laid-Open No. 2000-195998. By orienting the fibers in the thickness direction of the silicone rubber, a method for manufacturing a sheet having anisotropic thermal conductivity of high thermal conductivity in the thickness direction of the sheet has been proposed. When a sheet is produced in this way, a sheet having a higher thermal conductivity in the thickness direction than a sheet obtained by a conventional manufacturing method can be obtained, but when the carbon fiber is filled at a high density in the thickness direction, the surface hardness of the sheet increases. There is a disadvantage that the adhesion between the heat generating component and the heat radiating member decreases, and the thermal resistance increases.

In addition, in Japanese Patent Registration No. 3345986, a polymer block can be formed through lamination of a graphite film obtained by heat treatment at a temperature of 2,400 ° C. or higher, and a graphite block that can be formed is thinly cut in a direction perpendicular to the graphite surface, thereby providing high thermal conductivity in the thickness direction. It is proposed a method for obtaining a graphite sheet having a. However, the material obtained by such a method is a heat-radiating member having a high hardness enough to be referred to as a plate rather than a sheet form, and there is a problem that it is difficult to effectively reduce the heat resistance at the interface between the heating element and the heat-radiating member.

Japanese Patent Publication No. 2000-195998 (July 14, 2000) Japanese Registered Patent No. 3345986 (April 25, 1995)

The present invention was devised to solve the above problems, and in producing a high heat dissipation carbon sheet, heat is generated by dispersing the fibrous thermal conductor and filler in the adhesive layer, and oriented the fibrous thermal conductor in the thickness direction of the adhesive layer. It is an object of the present invention to provide a high heat dissipation carbon sheet capable of effectively diffusing negative heat and a method for manufacturing the same.

Another object of the present invention is to provide a high heat dissipation carbon sheet further added with a dispersing aid to improve the dispersibility of the fibrous thermal conductor and filler located in the adhesive layer, and a method for manufacturing the same.

The present invention relates to a thermal interface sheet and a method for manufacturing the same.

One aspect of the present invention is a base film layer; A graphite sheet layer laminated on one surface of the base film layer to support the base film layer; An adhesive layer laminated on one surface of the graphite sheet layer to adhere to the heating element; And a release film laminated on one side of the adhesive layer to protect the adhesive layer; wherein the adhesive layer comprises a base resin, a fibrous thermal conductor, a filler, and a dispersing aid, wherein the fibrous thermal conductor It relates to a high heat dissipation carbon sheet, characterized in that it has a structure oriented in the thickness direction of the adhesive layer.

In the present invention, the fibrous thermal conductor is a carbon fiber having a thickness of 0.1 to 5㎛, and the filler is carbon nanotube, graphene, graphite, fullerene, aluminum oxide, copper oxide, silver oxide, gold oxide, palladium oxide, platinum oxide , Any one or a plurality selected from nickel oxide and yttrium oxide.

In the present invention, more specifically, the aluminum oxide and yttrium oxide are mixed in a weight ratio of 60 to 80: 20 to 40, and the dispersion aid may be a polyallylamine derivative.

In the present invention, the base resin is polydimethylsiloxane resin, epoxy resin, acrylate resin, organopolysiloxane resin, polyimide resin, fluorocarbon resin, benzocyclobutene resin, fluorinated polyallyl ether resin, polyamide resin, polyimidoamide resin , Cyanate ester resin, phenol resol resin, aromatic polyester resin, polyphenylene ether resin, bismaleimide triazine resin and any one or more selected from fluoro resin.

In addition, the adhesive layer is characterized in that it comprises 50 to 75% by weight of the base resin, 10 to 30% by weight of the fibrous thermal conductor, 10 to 30% by weight of the filler, and 1 to 10% by weight of the dispersing aid.

Another aspect of the invention,

a) preparing a composition by mixing a base resin, a fibrous thermal conductor, a filler, and a dispersing aid;

b) preparing a graphite sheet layer laminated on one surface of the base film layer and the base film layer to support the base film layer;

c) forming an adhesive layer by applying the composition on one surface of the graphite sheet layer, and laminating a release film on the adhesive layer; And

d) curing the adhesive layer;

It relates to a method for producing a high heat dissipation carbon sheet comprising a.

In the present invention, step d) is characterized in that a fibrous thermal conductor in the adhesive layer is oriented in the thickness direction of the adhesive layer and cured at the same time by applying a magnetic field or an electric field, and the composition is 50 to 75% by weight of the base resin, fibrous It may include 10 to 30% by weight of the heat conductor, 10 to 30% by weight of the filler, and 1 to 10% by weight of the dispersion aid.

The high heat dissipation carbon sheet according to the present invention orients the fibrous thermal conductor present in the adhesive layer in the thickness direction of the adhesive layer, so that the fibrous thermal conductor acts as a channel connecting the heat generating part and the outside to effectively adhere the heat of the heating element. It can diffuse to the top of the layer. In addition, by further including at least one dispersing aid to increase the dispersibility of the fibrous thermal conductor having poor dispersibility in the polymer, the fibrous thermal conductor in the adhesive layer can be evenly dispersed and orientation can be further increased.

The high heat dissipation carbon sheet according to the present invention can further improve the lifespan of electronic components and devices included in automobile interior materials, batteries, displays, etc. due to the above characteristics, and by directly contacting consumers with portable electronic devices such as mobile devices. The feeling of rejection of the fever that can be felt can be eliminated, and the process cost and mass production cost can be greatly reduced compared to the technology using simple lamination or graphene.

1 is a cross-sectional view showing a method of manufacturing a high heat dissipation carbon sheet according to an embodiment of the present invention.

Hereinafter, a high heat dissipation carbon sheet and a method for manufacturing the same according to the present invention will be described in detail with reference to specific examples. The following specific examples are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art.

Therefore, the present invention is not limited to the specific examples presented below, but may be embodied in other forms, and the specific examples presented below are only described to clarify the spirit of the present invention, and the present invention is not limited thereto.

At this time, unless there are other definitions in the technical terms and scientific terms to be used, it means that those skilled in the art to which the present invention pertains have the meanings commonly understood, and unnecessarily obscure the subject matter of the present invention in the following description. Descriptions of possible known functions and configurations are omitted.

In addition, the following drawings are provided as an example in order to sufficiently convey the spirit of the present invention to those skilled in the art. Therefore, the present invention is not limited to the drawings presented below, and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. Also, the same reference numbers throughout the specification indicate the same components.

Also, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to the other component, but another component between each component It should be understood that elements may be "connected", "coupled" or "connected".

High heat dissipation carbon sheet according to the present invention

Base film layer;

A graphite sheet layer laminated on one surface of the base film layer to support the base film layer;

An adhesive layer laminated on one surface of the graphite sheet layer to adhere to the heating element; And

A release film laminated on one side of the adhesive layer to protect the adhesive layer;

It can be made including.

In the present invention, the base film layer is a base substrate layer that supports the graphite sheet layer, the adhesive layer, and the release film, and has a certain hardness or higher to protect the adhesive layer and the like from external impacts, and if necessary, detach from the graphite sheet layer. By doing so, it can also play the role of a release film.

In the present invention, the base film layer may include a base film and a release coating layer formed on one surface of the base film to adhere to the graphite sheet layer.

The base film is not limited to the type as long as it can be generally used for the outermost layer in a film module stacked in multiple layers. As an example, the material of the base film is a polyethylene terephthalate film, a polyethylene naphthalate film, a polyethersulfone film, a polycarbonate film, and a polypropylene film. And it may be made of any one or a plurality selected from the acrylic film.

The release coating layer is for maintaining the adhesion of the base film layer, may be formed from a release composition containing a silicone-based resin and a silicone-based curing agent, the silicone-based resin may include a polydimethylsiloxane having a vinyl group in the side chain.

The polydimethylsiloxane is a very flexible polymer having rubber-like properties, and the curing reaction is also actively progressed to ensure durability. In addition, the silicone-based curing agent includes one or more silane compounds and siloxane compounds, and may react with the polydimethylsiloxane to form a release coating layer having a certain adhesive or strength.

In addition, the release coating layer may be further provided with an adhesive layer comprising at least one adhesive component selected from acrylic, epoxy, urethane, silicone, and the like.

In the present invention, the graphite sheet layer may serve as a kind of heat sink that discharges heat transferred from the adhesive layer to the outside.

The graphite is a carbon material having a structure in which a carbon-bond of a network structure is stacked in multiple layers, and can form an overlapped laminated structure of carbon atoms in which each layer is bonded to each other by a weak van der Waals force.

The graphite sheet has excellent mechanical properties such as horse and tensile strength, elastic modulus, and flexural modulus, has high thermal conductivity caused by free electrons and lattice vibration, and has a high surface area to easily spread the transferred heat into the air and dissipate heat characteristics Can achieve. In addition, the low cost can significantly lower the process cost compared to diamond or graphene, which have the same effect.

In the present invention, the adhesive layer is in direct contact with a heat source, and serves to rapidly transfer heat generated from the heat source to the graphite sheet.

The adhesive layer includes a base resin, a fibrous thermal conductor, a filler, and a dispersing aid, and has a structure in which the fibrous thermal conductor is oriented in the thickness direction of the adhesive layer, so that the thermal conductor is a kind of channel connecting the heat source and the graphite sheet It has a better heat dissipation effect than other TIMs (thermal interface materials).

In the present invention, the base resin is a receptor that accommodates a fibrous thermal conductor, a filler, and a dispersing aid therein, and is a substrate forming the adhesive layer.

In the present invention, the base resin has ductility, so that it can be easily adhered to a heat source, has excellent workability, and has excellent heat resistance, so that no deformation occurs in the resin even when it is supplied with sustained heat. It is good to use a substance having a.

Examples of the base resin in the present invention are polydimethylsiloxane resin, epoxy resin, acrylate resin, organopolysiloxane resin, polyimide resin, fluorocarbon resin, benzocyclobutene resin, fluorinated polyallyl ether resin, polyamide resin, polyimido Amide resin, cyanate ester resin, phenol resol resin, aromatic polyester resin, polyphenylene ether resin, bismaleimide triazine resin, fluoro resin or mixtures thereof can be used. The polymer can be thermoplastic or thermoset, and can be selected depending on the desired final properties (eg, viscosity, modulus and elasticity). Suitable examples of the curable thermosetting matrix include acrylate resins, epoxy resins and polydimethylsiloxane resins, and also free radical polymerization, atomic transfer, radical polymerization ring-opening polymerization, ring-opening metathesis polymerization, anionic polymerization, cationic polymerization or any of those known to those skilled in the art. Other organic functional polysiloxane resin that can form a cross-linked network structure through other methods of. For non-curable polymers, the fished thermal interface material can be formulated as a gel, grease, or phase change material that can hold the parts together during manufacture and provide heat transfer during operation.

Specifically, the polymer matrix can be a polysiloxane resin, such as a silicone rubber composition that is additive curable. Such compositions include one or more organopolysiloxane components (e.g., an organopolysiloxane containing an average of two or more silicon-bonded alkenyl groups per molecule), one or more organohydrogen polysiloxanes acting as crosslinking agents (e.g., an average of two or more silicon-bonded hydrogens per molecule) Organohydrogen polysiloxanes containing atoms), and hydrosilylation catalysts (such as ruthenium, rhodium, platinum or palladium complexes), and optionally one or more catalyst inhibitors (used to modify the curing profile and improve shelf life) and 1 And more than one adhesion promoter.

The polymer matrix can further include various additives to achieve the desired overall properties of the thermal interface material. For example, reactive organic diluents can be added to reduce the viscosity of the polymer matrix when combined with fillers. In addition, non-reactive diluents can be added to reduce the viscosity of the formulation. It may also include pigments mixed with one or more pigments or carrier liquids. In the case of epoxy resins, various known strengthening agents, curing agents and / or other optional reagents can be used with the curing catalyst.

For example, in order to disperse the filler or the fibrous thermal conductor, dispersants such as fatty acid, fish oil, polydiallyldimethyl ammonium chloride, polyacrylic acid, and polystyrene sulfonate may be added, and polyvinyl alcohol, polyvinyl butyral, Binders such as wax may be mixed.

In the present invention, the base resin is preferably added in an amount of 50 to 75% by weight of 100% by weight of the total composition. When less than 50% by weight is added, it is difficult to properly form the adhesive layer because the content of the substrate is small, and when more than 75% by weight is added, the content of other components is reduced, which can significantly decrease the thermal conductivity.

In the present invention, the fibrous thermal conductor is a channel for rapidly transferring the heat conducted from the heat source to the graphite sheet layer or the outside, and may include carbon fiber.

It is preferable that the fibrous thermal conductor is oriented in the thickness direction of the adhesive layer to directly connect the heat source and the graphite sheet layer. Orientation of the fibrous thermal conductor is to use the conductivity of the fibrous thermal conductor, and before curing of the base resin constituting the adhesive layer, it is charged in the thickness direction of the adhesive layer to induce alignment of the fibrous thermal conductor within the adhesive layer. can do.

In the present invention, the fibrous heat conductor is preferably carbon fiber for ease of process and cost. In this case, the thermal conductivity of the carbon fiber is not particularly limited, but the thermal conductivity in the longitudinal direction is 400 W / m · or more, and more preferably 1,000 W / m · or more.

In the present invention, the fibrous thermal conductor is preferably limited in thickness (fineness). This is because if the thickness is too thin or too thick, the orientation may not be properly performed in the adhesive layer. The thickness of the fibrous thermal conductor is preferably 0.1 to 5㎛, more preferably 1 to 2㎛. If it is less than the above range, the stiffness of the fibrous thermal conductor may drop and bend in the adhesive layer. If it is more than the above range, the stiffness may be excessive and the fibrous thermal conductor may not move even during charging.

In addition, the fibrous thermal conductor may be further doped with magnetic ink or the like to further increase magnetic and thermal conductivity. This can be performed through an impregnation process of passing a fibrous thermal conductor through a container filled with a magnetic material such as UV mark ink.

In addition, in order to further improve the dispersibility and fluidity of the fibrous thermal conductor, surface treatment may be performed using one or more methods before being included in the adhesive layer. Carbon fiber has excellent molecular orientation and perfect physical properties and structure, but when mixed with a polymer due to agglomeration, they tend to clump together, and due to the low activity and smoothness of the fiber surface, the interfacial bonding force with the base resin Since it falls, it has a problem that movement is limited in the polymer even when charged. Therefore, it is desirable to improve the dispersibility through surface treatment so as to solve this and achieve stable heat conduction in all regions of the heat source.

In the present invention, the surface treatment of the fibrous thermal conductor is preferably an acid treatment using an acid such as sulfuric acid or nitric acid, more preferably a mixed acid in which sulfuric acid and nitric acid are mixed in a weight ratio of 1 to 5: 1. . At this time, the treatment time is not limited in the present invention, it is preferable to proceed for about 10 to 100 minutes, it is preferable in terms of maintaining dispersibility to proceed with ultrasonic treatment to the solution at the same time. In addition, after the surface treatment is finished, it is preferable to wash with methanol and lyophilize.

Alternatively, a sizing treatment may be performed by surface treatment of the fibrous thermal conductor. The sizing treatment is to increase the wettability of the fibrous thermal conductor to increase miscibility and fluidity in the polymer, and is to form a kind of coating film on the surface using a silane-based, sulfide-based, or imide-based interface binder. Examples of such sizing compositions and their treatment methods include those described in US 5298576 (Sumida et al., Toray Industries, 1994) and US 5589055 (Kobayashi et al., Toray Industries, 1996). .

In the present invention, the addition amount of the fibrous thermal conductor is preferably 10 to 30% by weight of 100% by weight of the total adhesive layer composition. If it is less than 10% by weight, the thermal conductivity may drop significantly, and when it is added above 30% by weight, the fluidity, processability, and adhesiveness of the adhesive layer may decrease.

In the present invention, the filler has a high thermal conductivity, like the fibrous thermal conductor, and easily transfers heat from a heat source and releases it to the graphite sheet layer or the outside, and also serves to increase the mechanical properties of the adhesive layer.

The filler is a metal oxide excellent in thermal conductivity, for example, aluminum oxide, copper oxide, silver oxide, gold oxide, palladium oxide, platinum oxide, nickel oxide and yttrium oxide, carbon nanotubes, graphene, graphite, fullerene, etc. It is preferable to include the same carbon material. In addition to the above materials, ceramic nanoparticles such as dry silica, fused silica, quartz powder, amorphous silica, aluminum nitride (AlN) or boron nitride (BN) may be added.

In the present invention, it is preferable to use a mixture of aluminum oxide and yttrium oxide in more detail as the filler. The aluminum oxide has high thermal conductivity, electrical resistance, and mechanical strength and is often used as a heat dissipation material due to its low dielectric constant, and when mixed with yttrium oxide, these properties are further amplified.

In the present invention, the mixing ratio of the aluminum oxide and yttrium oxide is preferably 60 to 80: 20 to 40 weight ratio. Optimal thermal conductivity may be exhibited in the above range, and in particular, when yttrium oxide is added in excess of the above range, the heat dissipation characteristics of the adhesive layer due to a decrease in the thermal conductivity of aluminum oxide may be deteriorated.

In the present invention, the amount of the filler is preferably 10 to 30% by weight of 100% by weight of the total adhesive layer composition. If it is less than 10% by weight, the thermal conductivity may drop significantly, and when it is added above 30% by weight, the fluidity, processability, and adhesiveness of the adhesive layer may decrease.

In addition, the composition according to the present invention may further add a dispersing aid to further improve the dispersibility of the inorganic material represented by the fibrous thermal conductor and filler, and the heat dissipation properties accordingly.

The dispersion aid in the present invention is to further increase the dispersibility of the fibrous thermal conductor and filler in the base resin, The polyallylamine derivative may be included as a main component.

In the present invention, the polyallylamine derivative may be obtained by first polymerizing allylamine in the presence of an initiator and a chain transfer catalyst to prepare polyallylamine, and then reacting polyester, polyamide and polyesteramide. The acidity of the polyallylamine derivative prepared by the above method may be 2.5 to 50 mg ·, and the weight average molecular weight may be 2,000 to 100,000.

In the present invention, the addition amount of the dispersion aid is preferably 1 to 10% by weight of 100% by weight of the total adhesive layer composition. If it is less than 1% by weight, the thermal conductivity may be greatly deteriorated due to insufficient movement of the fibrous thermal conductor during charging, and when it is added more than 10% by weight, moldability may decrease due to an increase in fluidity of the adhesive layer composition.

In addition, the adhesive layer may further include one or more additives when preparing the composition within a range not detrimental to the object of the present invention. Examples of the additives include plasticizers, curing agents (crosslinking agents), antioxidants, crosslinking aids, curing accelerators, scorch retarders, processing aids, coupling agents, ultraviolet stabilizers (including UV absorbers), antistatic agents, nucleating agents, slip agents, lubricants , Viscosity modifiers, tackifiers, antiblocking agents, surfactants, extenders, antacids, flame retardants, adhesion promoters, and metal non-active agents.

Examples of the plasticizer in the present invention include, but are not limited to, phthalic acid diesters (also known as "phthalates"), such as di-isononyl phthalate (DINP), diallyl phthalate (DAP), di-2-ethylhexylphthalate (DEHP ), Dioctyl phthalate (DOP) and diisodecyl phthalate (DIDP); Trimellitates such as trimethyl trimellitate, n-octyl trimellitate, and tri- (2-ethylhexyl) trimellitate; Adipate plasticizers such as bis (2-ethylhexyl) adipate, dimethyl adipate and dioctyl adipate; Sebacate-based plasticizers such as dibutyl sebacate; Maleate, such as dibutyl maleate; Benzoate; Sulfonamides such as N-ethyl toluene sulfonamide; Organophosphate; Polybutene; Glycol / polyethers such as triethylene glycol dihexanoate; Paraffinic process oils such as SUNPAR 2280 (Sunoco Corp.); Special hydrocarbon fluids, and polymer modifiers; And those derived from renewable sources such as epoxidized grains (eg, soybean, corn, etc.) oils (ie biochemical plasticizers).

Examples of the curing agent in the present invention include (1) free radical initiators (eg, organic peroxides or azo compounds), (2) silane functional groups generally activated with moisture (eg, vinyl alkoxy silanes or vinyl alkoxy) Silane functional polyolefins with silanes), (3) sulfur-containing curing agents to facilitate vulcanization, and / or (4) electromagnetic radiation (eg infrared (IR), ultraviolet (UV), visible, gamma rays , Etc.) to promote the crosslinking of the composition.

Examples of the scorch retarder in the present invention are 2,2,6,6-tetramethylpiperidinoxyl (TEMPO) and 4-hydroxy-2,2,6,6-tetramethylpiperidinoxyl (4-hydroxy Roxy TEMPO) and the like.

Examples of the ultraviolet stabilizer in the present invention include hindered amine light stabilizers (HALS) and ultraviolet absorbers (UVA) additives. Representative UVA additives include benzotriazole types, such as Tinuvin 326 and Tinuvin 328 commercially available from Ciba, Inc. Blends of HAL and UVA additives are also effective. Examples of antioxidants are hindered phenols such as tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane; Bis [(beta- (3,5-ditert-butyl-4-hydroxybenzyl) methylcarboxyethyl)]-sulfide, 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4 , 4'-thiobis (2-tert-butyl-5-methylphenol), 2,2'-thiobis (4-methyl-6-tert-butylphenol), and thiodiethylene bis (3,5-di -tert-butyl-4-hydroxy) -hydrocinnamate; Phosphites and phosphonites such as tris (2,4-di-tert-butylphenyl) phosphite and di-tert-butylphenyl-phosphonite; Thio compounds such as dilaurylthiodipropionate, dimyristylthiodipropionate, and distearylthiodipropionate; Various siloxanes; Polymerized 2,2,4-trimethyl-1,2-dihydroquinoline, n, n'-bis (1,4-dimethylpentyl-p-phenylenediamine), alkylated diphenylamine, 4,4'- Bis (alpha, alpha-dimethylbenzyl) diphenylamine, diphenyl-p-phenylenediamine, mixed di-aryl-p-phenylenediamine, and other hindered amine anti-degradants or stabilizers .

Examples of processing aids include, but are not limited to, metal salts of carboxylic acids, such as zinc stearate or calcium stearate; Fatty acids such as stearic acid, oleic acid, or erucic acid; Fatty amides, such as stearamide, oleamide, erucamide, or N, N'-ethylene bis-stearamide; Polyethylene wax; Oxidized polyethylene wax; Polymers of ethylene oxide; Copolymers of ethylene oxide and propylene oxide; Vegetable wax; Petroleum wax; Non-ionic surfactants; And silicone fluids and polysiloxanes.

In the present invention, the release film is formed on one side of the adhesive layer to protect the adhesive layer, and is removed from the adhesive layer as necessary. Similar to the base film layer, the base film and the base film are formed on one side of the adhesive It may include a release coating layer that adheres to the layer. At this time, the base film and the release coating layer may be the same or different from the components constituting the base film layer and the release coating layer.

In the present invention, the method of manufacturing the thermal interface sheet,

a) preparing a composition by mixing a base resin, a fibrous thermal conductor, a filler, and a dispersing aid;

b) preparing a graphite sheet layer laminated on one surface of the base film layer and the base film layer to support the base film layer;

c) forming an adhesive layer by applying the composition on one surface of the graphite sheet layer, and laminating a release film on the adhesive layer; And

d) curing the adhesive layer;

It may include.

In the present invention, the composition does not limit the manufacturing method. The composition can be mixed by adding it to a batch or continuous mixer for melt blending. At this time, in order to increase dispersibility, one or more components including a fibrous thermal conductor may be added in a form of a masterbatch. After adding all the composition to the mixer, heat is applied to the melting point of the base resin to ensure that all the ingredients are mixed, and then applied to the surface of the graphite sheet layer through an extruder, or converted into pellets and films to be fed to the next processing step. Can be.

The formulation of the composition can be performed by standard equipment known to those skilled in the art. Examples of compounding equipment are internal batch mixers, such as Banbury ™ or Bolling ™ internal mixers. Alternatively, a continuous single-screw, or twin-screw, mixer such as a Farrel ™ continuous mixer, a Werner and Pfleiderer ™ twin-screw mixer, or a Buss ™ kneaded continuous extruder can be used. The type of mixer used and the operating conditions of the mixer can affect the properties of the composition, such as viscosity, volume resistivity, and extruded surface flatness.

 Next, a graphite sheet layer laminated on one surface of the base film layer and the base film layer is prepared. The base film layer includes an adhesive layer on one surface as described above, and may have a form in which two layers are stacked by adhering it to the graphite sheet layer.

Then, the composition is applied to one surface of the graphite sheet layer to form an adhesive layer. At this time, the method of applying the composition may be a general coating method used when coating a coating liquid having a certain viscosity by a method such as comma coating, slot die coating, silk screen, etc., which can be conventionally used in the art.

The coated adhesive layer composition is coated with a release film before curing to determine the shape of the high heat dissipation carbon sheet. In addition, a magnetic field or an electric field may be applied to orient the fibrous thermal conductor present in the adhesive layer composition in the thickness direction of the adhesive layer.

If this is described in more detail through FIG. 1, since the adhesive layer 100 in which the fibrous thermal conductor 110 and the filler 120 are mixed is spread by being coated by a coater, the internal fibrous thermal conductor has a thickness direction based on the cross section. Instead, it is arranged in the horizontal direction. However, since the fibrous thermal conductor is easy to heat transfer in the longitudinal direction of the fiber, in the case of having such a structure, the thermal conductivity in the surface direction is excellent, but the thermal conductivity in the thickness direction is relatively inferior.

The present invention is characterized by rearranging the fibrous heat conductor from the horizontal direction to the thickness direction by applying electric power to the fibrous heat conductor, which is a conductive material, to solve this disadvantage.

Specifically, after placing a high heat dissipation carbon sheet including the adhesive layer 100 between the positive electrode and the negative electrode 200, a voltage is applied through the power source 300 to form an electromagnetic field between the positive electrode and the negative electrode. Through this, the fibrous thermal conductor 110 in the adhesive layer that has not yet been cured is arranged in the thickness direction along the electromagnetic field, and the thermal conductivity in the thickness direction of the adhesive layer can be greatly improved.

The energy density of the electric or magnetic field is not limited to the present invention, but is preferably 0.1 to 20 T (tesla), more preferably 10 to 15 T. When the energy density is less than 0.1T, the fibrous thermal conductor is not sufficiently oriented, and when it is more than 20T, it is not preferable to apply energy significantly higher than the energy density required for orientation.

The adhesive layer composition may undergo curing simultaneously with the orientation of the fibrous thermal conductor. At this time, the curing method may vary depending on the type of base resin constituting the adhesive layer composition, for example, curing methods such as photocuring, thermal curing, solvent evaporation.

When the high heat dissipation carbon sheet according to the present invention is applied to a heating electric product, the heat conductivity in the thickness direction of the adhesive layer is significantly higher than that of other high heat dissipation carbon sheets, so that heat generated from a heat source can be easily diffused in the sheet thickness direction. , It can easily remove heat generated from semiconductor devices and electronic components included in various semiconductors, automobile-related products, battery heat-radiating materials, etc., and prevent performance degradation due to heat generation, which can greatly contribute to securing long-term reliability of the final product.

Hereinafter, a high heat dissipation carbon sheet according to the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples and comparative examples are only examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The physical properties of the specimens prepared through the following examples and comparative examples were measured as follows.

(Thermal conductivity)

The thermal conductivity in the thickness direction was measured using an LFA 457 microflash measuring device (Netschach, Germany).

(Temperature drop width)

After attaching the specimen to the heating element and measuring the temperature with a non-contact thermometer, the temperature was measured with the same thermometer after 30 minutes.

(Example 1)

A polyacrylate resin was prepared as the base resin. Then, a carbon fiber having a diameter of 2 μm, copper oxide (CuO) as a filler, and a polyallylamine derivative (Mw: 10,000) as a dispersing aid were mixed and stirred to complete an adhesive layer composition. At this time, the composition ratio was 65% by weight of the base resin, 15% by weight of the carbon fiber, 15% by weight of the filler, and 5% by weight of the dispersion aid.

The finished composition was coated with a 30 µm thick uneven graphite heat dissipating paper with a polypropylene release film attached thereto, and a release film was laminated thereon again. Then, after passing the laminated sheet through a magnetic field application device applied with an energy density of 12T, UV curing was performed to complete a high heat dissipation carbon sheet. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Example 2)

When preparing the adhesive layer composition in Example 1, a high heat dissipation carbon sheet was completed in the same manner except that aluminum oxide was used as a filler to replace copper oxide. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Example 3)

When preparing the adhesive layer composition in Example 1, a mixture of aluminum oxide and yttrium oxide in a weight ratio of 70:30 was used as a filler, and a high heat dissipation carbon sheet was completed in the same manner. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Example 4)

When preparing the adhesive layer composition in Example 1, a high heat dissipation carbon sheet was completed in the same manner except that the content of the base resin was 45% by weight and the content of the filler was 35% by weight. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Example 5)

When preparing the adhesive layer composition in Example 1, the sheet was completed in the same manner, except that the content of the base resin was 58% by weight and the content of the dispersion aid was 12% by weight. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Comparative Example 1)

The sheet was completed in the same manner as in Example 1, except that a magnetic field application process was not performed when the adhesive layer composition was prepared. The physical properties of the finished sheet were measured and are shown in Table 1 below.

(Comparative Example 2)

When preparing the adhesive layer composition in Example 1, the sheet was completed in the same manner, except that 70% by weight of the base resin was added without adding a dispersing aid. The physical properties of the finished sheet were measured and are shown in Table 1 below.

[Table 1]

As shown in Table 1, the high heat dissipation carbon sheet according to the present invention shows excellent thermal conductivity and temperature drop. Particularly, Example 2 using aluminum oxide instead of copper oxide as a filler and Example 3 using a mixture of aluminum oxide and yttrium oxide show a more excellent thermal diffusion effect. On the other hand, Example 4 in which the filler content is too high shows a thermal diffusion effect of more than a certain level, but the adhesive layer and the heat source are poor due to excessive addition of the filler, so that the thermal diffusion effect of Example 3 or higher is not produced, and a dispersion aid It can be seen that Example 5 in which the content of was increased was also poor in the adhesion state with the heat source due to the increase in fluidity of the adhesive layer, so that the thermal diffusion effect was lower than in Example 3.

As described above, it has been described with reference to preferred embodiments and test examples of the present invention, but those skilled in the art may vary the present invention within the scope not departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that it can be modified and changed.

100: adhesive layer
110: fibrous thermal conductor
120: filler
200: electrode (anode, cathode)
300: power

Claims (10)

Base film layer;
A graphite sheet layer laminated on one surface of the base film layer to support the base film layer;
An adhesive layer laminated on one surface of the graphite sheet layer to adhere to the heating element; And
A release film laminated on one side of the adhesive layer to protect the adhesive layer;
A high heat dissipation carbon sheet comprising, the adhesive layer,
50 to 75% by weight of the base resin, 10 to 30% by weight of the fibrous thermal conductor surface-treated with a mixed acid in which sulfuric acid and nitric acid are mixed at a weight ratio of 1 to 5: 1, and aluminum oxide and yttrium oxide 60 to 80: 20 to 20 to 10 to 30% by weight of the filler mixed in a 40 weight ratio and 1 to 10% by weight of a dispersing auxiliary agent containing a polyallylamine derivative, wherein the fibrous thermal conductor has a structure oriented in the thickness direction of the adhesive layer. High heat dissipation carbon sheet.
According to claim 1,
The fibrous thermal conductor is a high heat dissipation carbon sheet, characterized in that the carbon fiber having a thickness of 0.1 to 5㎛.
delete delete delete According to claim 1,
The base resin is polydimethylsiloxane resin, epoxy resin, acrylate resin, organopolysiloxane resin, polyimide resin, fluorocarbon resin, benzocyclobutene resin, fluorinated polyallylether resin, polyamide resin, polyimidoamide resin, and cyanate High heat-resistant carbon sheet, characterized in that any one or a plurality of selected from ester resins, phenol resol resins, aromatic polyester resins, polyphenylene ether resins, bismaleimide triazine resins and fluoro resins.
delete a) 50 to 75% by weight of the base resin, 10 to 30% by weight of the fibrous thermal conductor surface-treated with a mixed acid in which sulfuric acid and nitric acid are mixed in a weight ratio of 1 to 5: 1, aluminum oxide and yttrium oxide 60 to 80: Preparing a composition by mixing 10 to 30% by weight of a filler mixed in a 20 to 40% by weight ratio and 1 to 10% by weight of a dispersing aid containing a polyallylamine derivative;
b) preparing a graphite sheet layer laminated on one surface of the base film layer and the base film layer to support the base film layer;
c) forming an adhesive layer by applying the composition on one surface of the graphite sheet layer, and laminating a release film on the adhesive layer; And
d) curing the adhesive layer;
Method for producing a high heat dissipation carbon sheet comprising a.
The method of claim 8,
The step d) is a method of manufacturing a high heat dissipation carbon sheet, wherein the fibrous thermal conductor inside the adhesive layer is oriented in the thickness direction of the adhesive layer and cured at the same time by applying a magnetic field or an electric field.
delete

Images