KR102076200B1 - Graphite composition, mater batch comprising the same and graphite composite material comprising the same - Google Patents

Abstract

Graphite compositions are provided. The graphite composition according to an embodiment of the present invention includes a graphite composite in which nanoparticles having a catecholamine layer on a surface thereof are fixed on graphite, and at least one of graphite flakes, spherical graphite, and expanded graphite. According to this, as the graphite composition has a high dispersibility in the substrate which is a dissimilar material, the composite material thus formed exhibits uniform heat dissipation performance, and can prevent a decrease in mechanical strength at a specific position. In addition, the composite material is excellent in compatibility with the substrate is a heterogeneous material excellent in interfacial properties with the substrate can realize a further improved heat dissipation performance and mechanical strength. Furthermore, it is very easy to mold during molding through injection / extrusion, etc., which is complex with the base material, and molding into a complicated shape is also possible.

Description

Graphite composition, master batch comprising the same, and graphite composite material embodied therethrough {Graphite composition, mater batch comprising the same and graphite composite material comprising the same}

The present invention relates to a graphite composition, and more particularly, a graphite composition which is easy to inject into various shapes while being excellent in light weight and heat dissipation performance, and enables to realize a heat dissipation member having excellent mechanical strength and durability of an injection molding, It relates to a masterbatch and graphite composites embodied therewith.

Heat accumulation in electronic components, lights, converter housings and other unwanted heat generating devices can greatly limit the working life and reduce operating efficiency. Metals, which are good thermal conductors, have typically been used for heat management devices such as heat sinks and heat exchangers. However, the metal part has a problem that the weight is heavy and the production cost is high.

Recently, a heat dissipation member manufactured by injection molding or extruded polymer resin has been proposed, and many studies have been conducted due to advantages such as light weight and low cost due to the material properties of the polymer resin itself.

The heat dissipation member is provided with a heat dissipation filler in order to express the desired heat dissipation, the heat dissipation filler is a heterogeneous material with a low thermal conductivity polymer resin, there is a problem in compatibility between different materials. For example, ideally, it may be advantageous in the heat dissipation performance that the heat dissipation filler is uniformly dispersed in the polymer resin, but in reality, the heat dissipation filler is more likely to be concentrated in a specific position in the polymer resin, and in this case, the heat dissipation performance is significantly reduced, There is a problem that the mechanical strength is significantly lowered due to frequent cracking or cutting at a specific position where the heat dissipation filler is concentrated. In addition, when the content of the heat dissipation member in the heat dissipation member is excessively increased, the heat dissipation member manufactured may have a significantly lower mechanical strength, and as the molding becomes difficult, there is a problem in that the heat dissipation filler content that can be provided in the heat dissipation member is limited.

Accordingly, there is an urgent need to develop a heat dissipation filler composition that ensures lightness while sufficiently expressing heat dissipation performance to a desired level, and excellent in mechanical strength and durability, and to realize a heat dissipation member excellent in injection molding.

Published Patent Publication No. 10-2016-0031103

The present invention has been made in view of the above point, the present invention is excellent in dispersibility in the base material of the dissimilar material, it exhibits a uniform heat dissipation performance, and a graphite composition which can prevent a decrease in mechanical strength at a specific position The purpose is to provide.

In addition, the present invention has excellent interfacial properties with the substrate as it is excellent in compatibility with the dissimilar materials, and thus can exhibit improved heat dissipation performance and mechanical strength, and is easy to mold during molding through injection / extrusion. Another object is to provide a graphite composition that is improved and allows molding into complex shapes.

Furthermore, another object of the present invention is to provide a masterbatch for preparing a graphite composite, which can be easily prepared through the graphite composition according to the present invention.

In addition, it is another object of the present invention to provide a graphite composite material that exhibits excellent heat dissipation performance and excellent mechanical strength, is excellent in light weight, is excellent in economy, and is implemented in a complex shape.

In order to solve the above problems, the present invention provides a graphite composite having a nanoparticle having a catecholamine layer on its surface fixed on graphite; And graphite at least one of graphite flakes, spherical graphite, and expanded graphite.

According to one embodiment of the invention, the graphite composite and the graphite may be provided in a 1: 1 to 25 weight ratio, more preferably 1: 15 weight ratio.

In addition, the graphite composite may further include a polymer layer coated on at least the catecholamine layer.

In addition, the graphite composite may have an average particle diameter of 10 ~ 900㎛.

In addition, the graphite composite may have an average particle diameter of 50 ~ 600 ㎛.

The graphite flakes may have an average particle diameter of 10 μm to 1,000 μm, the expanded graphite may have an average particle diameter of 50 μm to 1,000 μm, and the spherical graphite may have an average particle diameter of 10 μm to 100 μm.

In addition, the graphite may be expanded graphite.

In addition, the graphite may include graphite flakes and expanded graphite, the expanded graphite and graphite flakes may be included in a weight ratio of 1: 1 to 20, more preferably 1: 1 to 13 weight.

The present invention also provides a masterbatch for preparing a graphite composite comprising a graphite composition and a thermoplastic polymer compound according to the present invention.

According to one embodiment of the invention, the graphite composition may be provided in 20 to 80% by weight of the total weight of the masterbatch.

The thermoplastic polymer compound may include polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), One compound selected from the group consisting of polyethersulfone (PES), acrylonitrile-butadiene-styrene interpolymer (ABS), polyetherimide (PEI) and polyimide, or two or more mixtures or copolymers Can be.

In addition, the present invention provides a graphite composite material having a heat-dissipating filler comprising a polymer matrix molded by a thermoplastic polymer compound and a graphite composition according to the present invention dispersed in the polymer matrix.

According to one embodiment of the invention, the group consisting of carbon fiber, glass fiber, calcium carbonate, magnesium carbonate, mica, talc, silicon carbide, kaolin, calcium sulfate, barium sulfate, silicon dioxide, ammonium hydroxide, magnesium hydroxide and aluminum hydroxide It may further comprise at least one strength improver selected from, wherein the strength improver may be included in 0.1 to 30 parts by weight based on 100 parts by weight of the graphite composition.

In addition, the thermoplastic polyurethane (TPU) and the thermoplastic polyolefin (TPO) may further include one type of impact improving agent, wherein the impact improving agent may be included in 0.1 to 30 parts by weight based on 100 parts by weight of the graphite composition.

The dispersant may further include at least one additive selected from the group consisting of an antioxidant, a work improving agent, a coupling agent, a flame retardant, a light stabilizer, a heat stabilizer, and a UV absorber.

In addition, a protective coating layer may be further provided on at least a part of the outer surface of the polymer matrix.

In addition, the present invention is a first heat radiation filler comprising a polymer matrix formed by including a thermoplastic polymer compound to form a core portion and a coating portion surrounding the core, the graphite composition according to the present invention including the inside of the core portion and the Provided is a graphite composite comprising pigments dispersed within the coating.

According to an embodiment of the present invention, the coating part may further include a second heat radiation filler.

In addition, the present invention provides a heat dissipating composite material comprising a graphite composite according to the present invention, and a support member provided to form at least one interface with the polymer matrix of the graphite composite.

According to the present invention, as the graphite composition has a high dispersibility in the substrate which is a dissimilar material, the composite material thus formed exhibits uniform heat dissipation performance, and can prevent a decrease in mechanical strength at a specific position. In addition, the composite material is excellent in compatibility with the substrate is a heterogeneous material excellent in interfacial properties with the substrate can realize a further improved heat dissipation performance and mechanical strength. Furthermore, it is very easy to mold during molding through injection / extrusion, etc., which is complex with the base material, and molding into a complicated shape is also possible. Thus, the composite material exhibits excellent heat dissipation performance and at the same time ensures excellent mechanical strength, light weight, and excellent economic efficiency, it can be widely applied in various technical fields requiring heat dissipation.

1 is a diagram of a graphite composite according to an embodiment of the present invention, Figure 1a is a perspective view of the graphite composite, Figure 1b is a cross-sectional view taken along the line X-X 'of Figure 1a,
2 to 5 are cross-sectional views of a graphite composite according to various embodiments of the present invention, and
6A and 6B are cross-sectional views of the heat dissipating composite material according to the embodiment of the present invention, in which the support members are disposed in different positions.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

The graphite composition according to an embodiment of the present invention includes a graphite composite in which nanoparticles having a catecholamine layer on a surface thereof are fixed on graphite, and at least one of graphite flakes, spherical graphite, and expanded graphite.

First, the graphite composite will be described.

The graphite composite 101 includes nanoparticles 20 and catecholamine layer 30 bonded to the surface of graphite 10, as shown in FIGS. 1A and 1B, and may further include a polymer layer 40. Can be.

The graphite 10 is a mineral formed by layering planar macromolecules superimposed in a planar infinitely connected six-membered ring of carbon atoms, and may be a kind known in the art, specifically, impression graphite, high crystalline graphite, and earth graphite It may be either natural graphite or artificial graphite. For example, when the graphite 10 is natural graphite, it may be expanded graphite obtained by expanding the expanded graphite, and may be advantageous to achieve the object of the present invention when the graphite composite and graphite described below are mixed and used. have. The artificial graphite may be prepared by a known method. For example, a thermosetting resin such as polyimide may be prepared in a film shape of 25 μm or less, and then graphitized at a high temperature of 2500 ° C. or higher to produce graphite in a single crystal state, or chemical vapor deposition by thermal decomposition of a hydrocarbon such as methane at high temperature (CVD It is also possible to produce high orientation graphite.

In addition, the shape of the graphite 10 may be a known shape such as spherical, plate-like or needle-like or an amorphous shape, for example, may be plate-like.

In addition, the average particle diameter of the graphite 10 may be 10 ~ 900㎛, more preferably may be 30 ~ 500㎛, for example may be 300㎛. If the average particle diameter of the graphite 10 becomes smaller than 10 μm, the dehydration process may be difficult by closing pores of the filtration filter in the washing process of the catecholamine component in the manufacturing process of the graphite composite 101.

In addition, the graphite 10 may be a high purity graphite having a purity of 99% or more, and may be advantageous to express more improved physical properties.

Next, the nanoparticles 20 bonded to the surface of the graphite 10 described above function as a medium capable of providing the catecholamine layer 30 described later on the graphite 10. In detail, the catecholamine layer capable of improving dispersibility in dissimilar materials of the graphite 10 may be provided on the surface of the graphite 10 as the functional group capable of mediating a chemical reaction is hardly provided. Since 30) is not easily provided on the surface of graphite 10, even if catecholamine is treated with graphite, the amount of catecholamine remaining in the graphite is very small. In addition, in order to solve this problem, there is a limit to increasing the amount of catecholamine provided on the surface of the modified graphite even if the reforming treatment so that the functional group is provided on the surface of the graphite. However, in the case of graphite having nanoparticles provided on its surface, as catecholamine is easily bonded onto the surface of the nanoparticle, there is an advantage of introducing catecholamine into the graphite in a desired amount.

In addition, in the graphite composite using a graphite composition or the heat dissipating composite, the nanoparticles 20 of the graphite composite 101 may function as anchors. That is, when the nanoparticles are not provided, there is an excited part due to lack of compatibility at the interface formed between the graphite outer surface and the polymer matrix and / or the support member, or the surface of the interface is lifted due to vibration, impact, etc., cracks in the polymer matrix, There exists a possibility that peeling may arise easily.

However, the nanoparticles in contact with the support member among the nanoparticles 20 provided in the graphite composite 101 function as anchors at the interface between the graphite 10 and the support member, and the nanoparticles in contact with the polymer matrix are graphite 10 and the polymer. By functioning as an anchor at the interface between the matrices, the separation of the polymer matrix from the support member can be prevented. Since the nanoparticles 20 of the graphite composite 101 serve as anchors to the polymer matrix, lifting of the interface between the polymer matrix and the graphite composite 101 may also be prevented.

The nanoparticles 20 may be a metal or a nonmetallic material present as a solid at room temperature. Non-limiting examples thereof include alkali metals, alkaline earth metals, lanthanides, actinides, transition metals, transition metals, Metal, and the like. For example, the nanoparticles may be Ni, Si, Ti, Cr, Mn, Fe, Co, Cu, Sn, In, Pt, Au, Mg, and combinations thereof, preferably Cu, Ni, or Si.

In addition, the nanoparticles 20 may have an average particle diameter of 5 ~ 100nm, more preferably 5 ~ 65nm, more preferably 10 ~ 50nm, through which to perform a function as an anchor May be suitable. If the average particle diameter of the nanoparticles is less than 5nm, the function as an anchor for improving the interface bonding characteristics between the support member and the polymer matrix may be insignificant. In addition, if the average particle diameter of the nanoparticles exceeds 100nm, the number of nanoparticles provided on the graphite surface of a limited area may be reduced, so that it may be difficult to express the interfacial bonding properties at a desired level. In addition, it is difficult to produce in the form of particles bound on the graphite, and there is a fear that it can be produced as a single nanopowder. In addition, even when formed on the graphite, it is difficult to implement in the shape of a particle as the graphite outer surface is widely covered, and thus the function may be degraded as an anchor. Furthermore, when the catecholamine layer is introduced as described below, as the amount of the catecholamine layer loaded in the graphite composite increases, the aggregation between the graphite composites becomes intensified, so that the dispersibility of the graphite composite in the polymer matrix decreases, and the uniform heat dissipation characteristics are expressed. It is difficult to do this, and there is a fear that the durability of the portion where the graphite composite is agglomerated is significantly lowered.

In addition, the nanoparticles 20 is preferably in a crystallized particle state, and may be provided to occupy an area of 10% or more, more preferably 10 to 70% of the total surface area of each graphite 10. In addition, the nanoparticles 20 may be provided in 3 to 50% by weight, more preferably 3 to 20% by weight based on the total weight of the graphite composite 101.

Next, the catecholamine layer 30 may be provided on at least the surface of the above-described nanoparticles 20, through which the excellent fluidity, dispersibility and graphite between the graphite composite and the polymer compound in the heterogeneous polymer compound described later. It is possible to improve the interfacial bonding properties. In addition, the catecholamine layer 30 itself has a reducing power, and at the same time, the amine functional group forms a covalent bond by Michael addition reaction to the catechol functional group on the surface of the layer, thereby making the secondary surface modification using the catecholamine layer as an adhesive material. This is possible, for example, it can act as a bonding material that can introduce the polymer layer 40 to the graphite in order to express more improved dispersibility in the polymer compound.

The catecholamine forming the catecholamine layer 30 has a hydroxy group (-OH) as an ortho-group of the benzene ring and a single molecule having various alkylamines as the para-group. As a non-limiting example of various derivatives of these constructs, dopamine, dopamine-quinone, epinephrine, alpha-methyldopamine, norepinephrine, alpha-methyl Dopa (alphamethyldopa), droxidopa (droxidopa), indolamine (indolamine), serotonin (serotonin) or 5-hydroxy dopamine (5-Hydroxydopamine) and the like, for example, the catecholamine layer 30 is dopamine (dopamine) Layer). The dopamine is a monomolecular substance having a molecular weight of 153 (Da) having a catechol and an amine functional group. For example, the dopamine is a substance to be surface-modified in an aqueous solution of basic pH conditions (about pH 8.5) containing dopamine represented by Formula 1 below. When put in and taken out after a certain time, a polydopamine (pDA) coating layer may be formed on the surface of the material by oxidation of catechol.

[Formula 1]

In Formula 1, at least one of R ₁ , R ₂ , R ₃ , R _4, and R ₅ is thiol, primary amine, primary amine, secondary amine, nitrile, and aldehyde, respectively. ), Imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic ester ester) or carboxamide, and the other one may be hydrogen.

In addition, the thickness of the catecholamine layer 30 may be 5 ~ 100nm, but is not limited thereto.

Meanwhile, the polymer layer 40 may be further coated on the catecholamine layer 30, and as the compatibility with the polymer compound forming the composite material increases due to the polymer layer 40, further improved flowability, dispersibility, and interface. Coupling characteristics can be implemented. The polymer layer 40 may be implemented with a thermosetting polymer compound or a thermoplastic polymer compound, and specific types of the thermosetting polymer compound and the thermoplastic polymer compound may be known. As a non-limiting example, the thermosetting polymer compound may be one compound selected from the group consisting of epoxy, urethane, ester and polyimide resins, or two or more mixtures or copolymers. The thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), It may be one compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more kinds. Alternatively, the polymer layer may be a rubber elastomer including natural rubber and / or synthetic rubber, and a similar material thereof.

In addition, when the polymer layer 40 is further provided, the polymer layer may have a thickness of 1 to 100 nm. In addition, the polymer layer 40 may be included 0.01 to 20% by weight based on the total weight of the graphite composite.

The above-described graphite composite 101 comprises the steps of preparing a graphite-nanoparticle conjugate in which nanoparticles are formed on a graphite surface; And forming a catecholamine layer on the graphite-nanoparticle binder. It may be prepared, and may be prepared by further forming a polymer layer after forming the catecholamine layer.

The step of preparing a graphite-nanoparticle conjugate in which nanoparticles are formed on a graphite surface according to an embodiment of the present invention may be employed without limitation in the case of a known method of forming nanoparticles on a graphite surface, and is not limited thereto. As an example, existing gas phase synthesis techniques for producing metal-based nanopowders include Inert Gas Condensation (IGC), Chemical Vapor Condensation (CVC), Metal Salt Spray-Drying, etc. The method of can be adopted. Among these, inert gas condensation (IGC) process is possible to manufacture high-purity ultra-fine nanometal powders, but it requires a large amount of energy and has a very low production rate, which limits industrial applications. Chemical vapor condensation (CVC) The process is somewhat improved in terms of energy and production rate compared to inert gas condensation (IGC) processes, but it can be uneconomical because the price of the precursor precursor is very expensive. In addition, the metal salt spray drying process is economical because cheap salt is used as a raw material, but it is unavoidable from the environmental point of view because contamination and agglomeration of powder in the drying step cannot be avoided and toxic by-products are generated.

Preferably, nanoparticles may be formed on graphite through atmospheric high-frequency thermal plasma. Specifically, mixing the graphite and nanoparticle-forming powder; Injecting gas into the prepared mixture; Vaporizing the nanoparticle forming material through high frequency thermal plasma; And crystallizing the vaporized nanoparticle-forming material on the graphite surface.

First, the mixing ratio between the two materials in the step of mixing the graphite and nanoparticle-forming powder may be designed differently depending on the purpose, but preferably, in order to provide a high density of nanoparticles, the nanoparticle-forming material is added to 100 parts by weight of graphite. 3 to 100 parts by weight can be mixed. At this time, it can mix using a separate stirrer.

Next, a gas may be injected into the mixed mixture, and the injected gas may be classified into cis gas, central gas, and carrier gas according to its function, which may include an inert gas such as argon, hydrogen, nitrogen, or the like. Gases mixed with these may be used, and argon gas may be preferably used. The sheath gas is injected to prevent the vaporized nanoparticles from adhering to the inner surface of the wall and to protect the wall from the ultra-high temperature plasma, and argon gas of 30 to 80 lpm (liters per minute) may be used. In addition, the central gas is a gas that is injected to generate a high temperature thermal plasma, it may be used argon gas of 30 ~ 70 lpm. In addition, the carrier gas is a gas for supplying the mixture into the plasma reactor, it may be used argon gas of 5 ~ 15 lpm.

Next, the nanoparticle forming material may be vaporized through high frequency thermal plasma. The thermal plasma is an ionization gas composed of electrons, ions, atoms and molecules generated by a plasma torch using a direct current arc or a high frequency inductively coupled discharge, and is a high temperature jet having a high temperature and high activity ranging from thousands to tens of thousands of K. . Accordingly, in order to smoothly generate a high temperature plasma, power is supplied from 10 to 70 kW to the power supply of the plasma apparatus, an arc is formed by electric energy, and about 10,000 by argon gas used as a thermal plasma generating gas. An ultra high temperature plasma of K is generated. As described above, the ultra-high temperature thermal plasma generated by using argon gas as the generating gas while maintaining power of 10 to 70 kW has an effect of being generated at a higher temperature than the thermal plasma generated by the heat treatment method or the combustion method. At this time, the present invention can be used by appropriately modifying the known high frequency thermal plasma (RF) method, it is also possible to use a conventional thermal plasma processing apparatus.

Next, the step of crystallizing the vaporized nanoparticle forming material on the graphite surface can be performed. In order to crystallize the vaporized nanoparticle formers at the graphite surface, a quenching gas may be used. At this time, by condensation or quenching with the quenching gas can be crystallized while inhibiting the growth of the nanoparticles.

Forming a catecholamine layer on the graphite-nanoparticle conjugate prepared by the above-described method, and specifically dipping the graphite-nanoparticle conjugate into the weakly basic dopamine aqueous solution; And forming a polydopamine layer on the surface of the graphite-nanoparticle conjugate.

First, the method for preparing the weakly basic dopamine aqueous solution is not particularly limited, but pH 8-14 tris buffer solution (10 mM, tris buffer solution), more preferably pH 8.5 basic tris which is the same basic conditions as the environment in the sea It may be prepared by dissolving dopamine in a buffer solution, wherein the dopamine concentration of the weakly basic dopamine aqueous solution may be 0.1 to 5 mg / ml, preferably 2 mg / ml.

After dipping the graphite-nanoparticle conjugate in the prepared weakly basic dopamine aqueous solution, dopamine may spontaneously polymerize under basic and oxidative conditions to form a catecholamine layer as a polydopamine layer on the graphite-nanoparticle conjugate. In this case, the polydopamine layer may be formed by further providing an oxidizing agent, and oxygen gas in the air may be used as the oxidizing agent without the oxidizing agent, and the present invention is not particularly limited thereto.

At this time, the dipping time determines the thickness of the polydopamine layer, pH 8 ~ 14, when using a dopamine aqueous solution with a dopamine concentration of 0.1 ~ 5mg / ㎖, in order to form a catecholamine layer to a thickness of 5 ~ 100nm preferably about Dipping for 0.5 to 24 hours is preferred. Pure plate-like graphite hardly forms a dopamine coating layer on the graphite surface through this method, but the catecholamine layer may be formed on the nanoparticles due to the nanoparticles. Meanwhile, dipping has been exemplified as the method of forming the polymer layer, but is not limited thereto. Blade coating, flow coating, casting, printing method, transfer method, brushing, or spraying may be used. The polymer layer can be further formed by a known method such as spraying.

Meanwhile, in order to further include a polymer layer in the graphite composite on which the catecholamine layer is formed, the graphite composite may be prepared by mechanically mixing the graphite composite in a dissolved solution or a melted melt in which a desired polymer compound is dissolved.

Next, the graphite mixed with the above-described graphite composite 101 will be described.

The graphite is responsible for inhibiting the secondary aggregation of the graphite composite 101 described above so that the graphite composite is better dispersed in the polymer compound, and to implement a lighter composite. The graphite composite described above includes a catecholamine layer in order to improve fluidity, dispersibility, and interfacial bonding properties when mixed with a polymer compound, but rather, secondary aggregation of graphite composites may occur due to the catecholamine layer. Dispersibility of the graphite composite may be inhibited in the implemented composite. The graphite prevents secondary agglomeration between graphite composites, thereby expressing uniform physical properties for each region of the composite material embodied therethrough, and preventing a decrease in mechanical strength due to agglomeration.

The graphite may be any one or more of graphite flakes, expanded graphite, and spherical graphite, and the graphite composite material formed through the above may express another effect or express more elevated physical properties. Can be. For example, the spherical graphite may be prepared by grinding the graphite flakes into a spherical shape.

The graphite flakes and the expanded graphite exhibit improved heat dissipation performance, especially in horizontal thermal conductivity, when mixed with the graphite composite, and can express excellent mechanical strength in the state in which they are dispersed in the polymer matrix. In addition, the spherical graphite may complement the vertical thermal conductivity of the graphite composite. Graphite has excellent thermal and electrical conductivity in the horizontal direction while the material itself has poor physical properties in the vertical direction. This is due to the movement of free charge like the metal bond in the horizontal direction, but not in the vertical direction. As a result, composites including ordinary graphite have different horizontal thermal conductivity and vertical thermal conductivity. There is a disadvantage that the heat dissipation effect is weak. However, in the case of the spherical graphite, it is possible to improve the disadvantages such as to improve the thermal conductivity in the vertical direction.

The graphite flakes may have an average particle diameter of 10 μm to 1,000 μm, more preferably 50 μm to 500 μm. In addition, the expanded graphite may have an average particle diameter of 50㎛ ~ 1,000㎛, more preferably 100㎛ ~ 500㎛. In addition, the spherical graphite may have an average particle diameter of 10㎛ ~ 100㎛, more preferably 20㎛ ~ 40㎛. If the average particle size of the graphite of each type satisfies the above numerical range, in addition to improving the thermal conductivity, it may be very advantageous to suppress the coagulation phenomenon of the graphite composite described above. In addition, the problem of graphite desorption in pellets, graphite composites or heat dissipating composites, which occurs as the particle diameter becomes very small, can be suppressed. In addition, it is possible to prevent the degradation of the fluidity of the graphite in the molten polymer compound generated when using the graphite exceeding the upper limit of the preferred particle size range for each type, or to reduce the surface quality in the graphite composite or heat dissipating composite.

On the other hand, when the average particle diameter of the graphite is smaller than the above-described average particle diameter of the graphite composite 101, the connection between some graphite may occur, in this case the polymer using bi-modal (bi-modal) between the large particles and small particles The closest filling in the matrix is possible, and the thermal conductivity can be better.

In addition, the graphite comprising any one or more of the graphite flakes, expanded graphite and spherical graphite is preferably 1: 1 to 25 weight ratio, more preferably 1: 1 to 15 weight ratio, even more preferred based on the graphite composite weight Preferably 1: 1 to 10 by weight. If the graphite is provided in a less than 1: 1 weight ratio based on the weight of the graphite composite, the degree of improvement in heat dissipation performance due to graphite may be insignificant, and it may be difficult to prevent aggregation of the graphite composite. In addition, there is a risk of cost increase as the majority of the heat dissipation filler should be provided as a graphite composite, and may not be desirable to reduce the weight of the composite material. On the other hand, if the graphite is provided in excess of 1:25 weight ratio based on the graphite composite weight may cause a decrease in heat dissipation characteristics of the composite material is implemented, in particular the surface of the composite material due to the heat radiation filler fluidity during the manufacturing process of the composite material It can be concentrated in the central portion rather than the portion, so that the radiated characteristics of the conducted heat and the vertical heat conduction performance can be significantly reduced. In addition, due to the deterioration of interfacial bonding properties between dissimilar materials, the spacing between the polymer matrix and the graphite and the interface between the polymer matrix and the support member may become more frequent and deeper.

On the other hand, according to one embodiment of the present invention, the graphite provided with the graphite composite 101 may be expanded graphite, through which compared to other types of graphite, such as tensile strength, flexural strength, flexural modulus, impact strength High mechanical strength and horizontal thermal conductivity can be achieved.

In addition, according to an embodiment of the present invention, the graphite provided with the graphite composite 101 may be graphite flakes and expanded graphite. In this case, in addition to excellent tensile strength, especially in the case of having only one type of expanded graphite or graphite flake, it can be very advantageous to achieve an elevated horizontal thermal conductivity. More preferably, the expanded graphite and graphite flakes may be included in a weight ratio of 1: 1 to 20, even more preferably 1: 1 to 13 weight ratio. In order to achieve the object of the present invention, if the graphite flakes are provided in a weight ratio of less than 1: 1 based on the weight of the expanded graphite, injection may be difficult by reducing fluidity in a mixed state with the molten polymer compound. It can be difficult. In addition, if the graphite flakes are provided in a weight ratio of more than 1:25 based on the weight of the expanded graphite, it may be difficult to achieve the elevated horizontal thermal conductivity. In addition, there is a fear that mechanical strength, such as tensile strength, flexural modulus, impact strength, is lowered.

The graphite composition comprising the graphite composite and graphite described above is implemented as a masterbatch for producing a graphite composite together with a thermoplastic polymer compound.

The graphite composite and graphite may be provided in 20 to 80% by weight, more preferably 30 to 70% by weight of the total weight of the masterbatch, if less than 20% by weight of the thermal conductivity of the graphite composite prepared through the masterbatch The physical properties of may be lowered. In addition, if it exceeds 80% by weight may be difficult to manufacture the masterbatch, the cracks, fractures of the prepared masterbatch may be severe and poor storage stability. In addition, the composite material implemented through this may also significantly reduce the mechanical strength.

The thermoplastic polymer compound may be a known thermoplastic polymer compound, and may be a material for forming a polymer matrix of the graphite composite material described later. The thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), It may be one compound selected from the group consisting of acrylonitrile-butadiene-styrene interpolymer (ABS), polyetherimide (PEI) and polyimide, or two or more mixtures or copolymers.

For example, the polyamide may be a known polyamide-based compound such as nylon 6, nylon 66, nylon 11, nylon 610, nylon 12, nylon 46, nylon 9T (PA-9T), kina and aramid.

For example, the polyester may be a known polyester-based compound such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polycarbonate.

For example, the polyolefin may be a known polyolefin-based compound such as polyethylene, polypropylene, polystyrene, polyisobutylene, ethylene vinyl alcohol, and the like.

The liquid crystal polymer may be used without limitation in the case of a polymer exhibiting liquid crystallinity in a solution or dissolved state, and may be a known kind, and thus the present invention is not particularly limited thereto.

On the other hand, the master batch for producing the graphite composite material may further include other additives such as strength improver, impact improver, antioxidant, heat stabilizer, light stabilizer, plasticizer, dispersant, work improver, coupling agent, UV absorber, antistatic agent, flame retardant. .

The strength improving agent may be used without limitation in the case of known components that can improve the strength of the composite material between the graphite composite and the heat-dissipating filler including the graphite and the polymer compound, non-limiting examples thereof, carbon fiber, glass fiber, Glass beads, zirconium oxide, ulastonite, gibbsite, boehmite, magnesium aluminate, dolomite, calcium carbonate, magnesium carbonate, mica, talc, silicon carbide, kaolin, calcium sulfate, barium sulfate, silicon dioxide, ammonium hydroxide At least one component selected from the group consisting of magnesium hydroxide and aluminum hydroxide may be included as a strength improving agent. The strength improving agent may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the graphite composition described above, but is not limited thereto. For example, when the strength improver is used glass fiber, the length of the glass fiber may be 2 ~ 8mm.

In addition, the impact modifier may be used without limitation in the case of known components that can improve the impact resistance by expressing the flexibility and stress relaxation of the composite between the graphite composite / graphite and the polymer compound, for example, thermoplastic polyurethane ( TPU), thermoplastic polyolefin (TPO), maleic acid grafted EPDM, core / shell structure elastic particles, rubber-based resins may be provided as an impact improving agent. The thermoplastic polyolefin is a group of materials similar to rubber, and is a linear polyolefin block copolymer having a polyolefin block such as polypropylene and polyethylene and a rubbery block or an ethylene-propylene-diene monomer (EPDM) which is an ethylene-based elastomer in polypropylene. As the specific thermoplastic polyolefin may be known, the present invention omits description of specific types thereof. In addition, since the thermoplastic polyurethane may also be known, a description of specific types will be omitted. In addition, the core / shell structure elastic particles may use an allyl-based resin as an example, and the shell portion may include a polymer having a functional group capable of reacting with the thermoplastic polymer compound to increase compatibility and bonding strength. It may be a resin.

In addition, the impact improving agent may be included in 0.1 to 30 parts by weight based on 100 parts by weight of the total graphite composition, but is not limited thereto.

In addition, the antioxidant is provided to prevent the generation of radicals due to heat and / or shear stress during extrusion, injection to prevent the breaking of the main chain of the thermoplastic polymer compound, and to prevent discoloration by heat generated in the secondary processing. . The antioxidant may be used without limitation known known antioxidants, non-limiting examples thereof include tris (nonyl phenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2 Organic phosphites such as, 4-di-t-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite or the like; Alkylated monophenols or polyphenols; Alkylated reaction products of polyphenols with dienes, such as tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane, or the like; Butylated reaction products of para-cresol or dicyclopentadiene; Alkylated hydroquinones; Hydroxylated thiodiphenyl ethers; Alkylidene-bisphenols; Benzyl compounds; Esters of beta- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionic acid with monohydric or polyhydric alcohols; Esters of monohydric or polyhydric alcohols with beta- (5-tert-butyl-4-hydroxy-3-methylphenyl) -propionic acid; Distearylthiopropionate, dilaurylthiopropionate, ditridecylthiopropionate, octadecyl-3- (3,5-di-tert-butyl-l-4-hydroxyphenyl) propionate Esters of thioalkyl or thioaryl compounds, such as pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate or the like; Amides of beta- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionic acid or the like, or mixtures thereof. The antioxidant may be provided in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the thermal stabilizer may be used without limitation in the case of known thermal stabilizers, but non-limiting examples thereof include triphenyl phosphite, tris- (2,6-dimethylphenyl) phosphite, tris- (mixed mono- Organic phosphites such as tris- (mixed mono-and di-nonylphenyl) phosphate) or the like; Phosphonates such as dimethylbenzene phosphonate or the like, phosphates such as trimethyl phosphate, or the like, or mixtures thereof. The heat stabilizer may be included in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the light stabilizer may be used without limitation in the case of known light stabilizers, but non-limiting examples thereof include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5 Benzotriazoles or mixtures thereof, such as -tert-octylphenyl) -benzotriazole and 2-hydroxy-4-n-octoxy benzophenone or the like. The light stabilizer may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the plasticizer may be used without limitation in the case of known plasticizers, but non-limiting examples thereof include dioctyl-4,5-epoxy-hexahydrophthalate, tris- (octoxycarbonylethyl) isocyanurate, Phthalic acid esters or mixtures thereof such as tristearin, epoxidized soybean oil or the like. The plasticizer may be included in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the antistatic agent may use a known antistatic agent without limitation, and as a non-limiting example, glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzenesulfonate, polyether block Amides, or mixtures thereof, these include, for example, BASF under the trade name Irgastat; Arkema under the trade name PEBAX; And Sanyo Chemical Industries under the trade name Pelestat. The antistatic agent may be included in an amount of 0.1 to 2.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the work improving agent may use any known work improving agent without limitation, and as a non-limiting example, metal stearate, stearyl stearate, pentaerythritol tetrastearate, beeswax, montan wax (montan) wax), paraffin wax, polyethylene wax or the like or mixtures thereof. The work improving agent may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the UV absorber, known UV absorbers can be used without limitation, non-limiting examples thereof, hydroxybenzophenone; Hydroxybenzotriazole; Hydroxybenzotriazine; Cyanoacrylate; Oxanilides; Benzoxazinones; 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3, -tetramethylbutyl) -phenol; 2-hydroxy-4-n-octyloxybenzophenone; 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) -phenol; 2,2 '-(1,4-phenylene) bis (4H-3,1-benzoxazin-4-one); 1,3-bis [(2-cyano-3,3-diphenylacryloyl) oxy] -2,2-bis [[(2-cyano-3,3-biphenylacryloyl) oxy] Methyl] propane; 2,2 '-(1,4-phenylene) bis (4H-3,1-benzoxazin-4-one); 1,3-bis [(2-cyano-3,3-diphenylacryloyl) oxy] -2,2-bis [[(2-cyano-3,3-diphenylacryloyl) oxy] Methyl] propane; Nano-size inorganic materials such as titanium oxide, cerium oxide and zinc oxide having a particle diameter of less than 100 nm; Or other similar ones, or mixtures thereof. The UV absorber may be included in an amount of 0.01 to 3.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the dispersant may be used without limitation in the case of a component known as a dispersant of the carbon-based heat-radiating filler. As a non-limiting example, polyester-based dispersants, polyphenylene ether-based dispersants; Polyolefin dispersant, acrylonitrile-butadiene-styrene copolymer dispersant, polyarylate dispersant, polyamide dispersant, polyamideimide dispersant, polyarylsulfone dispersant, polyetherimide dispersant, polyethersulfone dispersant, poly Phenylene sulfide dispersants, polyimide dispersants; Polyether ketone dispersant, polybenzoxazole dispersant, polyoxadiazole dispersant, polybenzothiazole dispersant, polybenzimidazole dispersant, polypyridine dispersant, polytriazole dispersant, polypyrrolidine dispersant, polydibenzofuran A system dispersing agent, a polysulfone type dispersing agent, a polyurea type dispersing agent, a polyurethane type dispersing agent, or a polyphosphazene type dispersing agent, etc. are mentioned, Two or more types or mixtures or copolymers selected from these can also be used.

The dispersant may be included in 0.2 to 6.0 parts by weight based on 100 parts by weight of the graphite composition.

In addition, the coupling agent may use any known coupling agent without limitation, and examples thereof include silane coupling agent, amine coupling agent, maleic acid graft polypropylene (MAH-g-PP) and maleic acid. One or more selected from the group consisting of graft EPDM (MAH-g-EPDM) can be used in combination. In addition, the coupling agent may be included in an amount of 0.01 to 8.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

The flame retardant can also be, for example, halogenated flame retardants, like tretabromo bisphenol A oligomers such as BC58 and BC52, brominated polystyrene or poly (dibromo-styrene), brominated epoxy, Decabromodiphenylene oxide, pentabrom penzyl acrylate monomer, pentabromobenzyl acrylate polymer, ethylene-bis (tetrabromophthalimide, bis (pentabromobenzyl) ethane, Mg (OH) ₂ and Al ( Metal hydroxides such as OH) ₃ , melamine cyanurates, phosphor based FR systems such as red phosphorus, melamine polyphosphates, phosphate esters, metal phosphinates, ammonium polyphosphates, expandable graphite Sodium or potassium perfluorobutane sulfate, sodium or potassium perfluorooctane sulfate, sodium or potassium di Phenylsulfonsulfonate and sodium- or potassium-2,4,6, -trichlorobenzoate and N- (p-tolylsulfonyl) -p-toluenesulphimid potassium salt, N- (N'-benzylaminocar Carbonyl) sulfanilimide potassium salt, or mixtures thereof, but the flame retardant may be included within 30 parts by weight based on 100 parts by weight of the graphite composition.

The process of preparing the masterbatch including the graphite composition, the thermoplastic polymer compound, and other additives described above may be a conventionally known method. For example, the prepared masterbatch may be in the form of a pellet, and a method of manufacturing a conventional pellet As can be manufactured through the present invention, a detailed description thereof will be omitted.

Next, a graphite composite material according to an embodiment of the present invention will be described.

As shown in FIGS. 2 and 3, the graphite composite material 1000, 1000 ′ is composed of a polymer matrix 200 formed of a thermoplastic polymer compound and a graphite composite 101 and graphite 102, 103 including the inside of the polymer matrix. It is implemented as a heat dissipation filler 100 containing a graphite composition according to the present invention, the protective coating layer 300 may be further provided on the outer surface of the polymer matrix (200).

The graphite composite 101 and the graphite 102 and 103 in the heat dissipation filler 100 are shown as being dispersed only inside the polymer matrix 200 in FIG. 2 or FIG. 3, but may be arranged to be exposed to the outer surface.

The graphite (102, 103) comprises any one or more of graphite flake, spherical graphite, expanded graphite, as shown in Figure 2, the heat dissipation filler 100 is one type of graphite, for example expanded graphite 102 is provided can do. Alternatively, as shown in FIG. 3, the heat dissipation filler 100 may include two kinds of graphites, and include graphite flakes 102 and spherical graphite 103, thereby simultaneously expressing improved vertical thermal conductivity and horizontal thermal conductivity. May be advantageous. Alternatively, the two types of graphite combinations may include expanded graphite and graphite flakes, thereby expressing excellent mechanical strength and elevated horizontal thermal conductivity of the composite as described above.

The heat dissipation filler including the graphite composite 101 and the graphite (102,103) is 10 to 90% by weight, more preferably 20 to 80% by weight, even more preferably 30 to 70 to the total weight of the graphite composite (1000) It may be provided in weight percent. If the heat dissipation filler is provided in less than 10% by weight may not exhibit the desired heat dissipation performance, shielding performance. In addition, if it is provided in excess of 90% by weight, the mechanical strength of the composite material is significantly reduced, the moldability, such as injection is reduced, it may be difficult to implement a complex shape.

The shape and size of the polymer matrix 200 is not limited. For example, the polymer matrix may be plate-shaped.

Meanwhile, the protective coating layer 300 protects the polymer matrix 200 from external physical / chemical stimuli, and prevents the graphite composite 101 or the graphite 102 and 103 from being detached from the polymer matrix 200. To perform. In addition, when the protective coating layer 300 is formed of an insulating material, it may provide insulation required for the heat radiating member of the electronic device.

The protective coating layer 300 may be implemented with known thermosetting polymer compounds or thermoplastic polymer compounds. The thermosetting polymer compound may be at least one compound selected from the group consisting of epoxy, urethane, ester, and polyimide resins, or mixtures or copolymers of two or more thereof. In addition, the thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES) ), One compound selected from the group consisting of polyetherimide (PEI) and polyimide, or mixtures or copolymers of two or more thereof.

The protective coating layer 300 may have a thickness of 0.1 to 1000 μm, but is not limited thereto. The protective coating layer 300 may be changed according to the purpose.

On the other hand, the protective coating layer 300 may be further provided with a known heat-dissipating filler of metal, carbon, and / or ceramic in order to improve the heat radiation and heat radiation characteristics to the outside air. In addition, when insulation is required at the same time, a known insulating heat-radiating filler such as aluminum oxide, boron nitride, talc, magnesium oxide, silicon carbide, or the like may be provided. When the protective coating layer 300 is a heat dissipation coating layer may have a thickness of 10 ~ 50㎛, if the thickness exceeds 50㎛ there is a problem that the radiation characteristics may be rather reduced.

In addition, the protective coating layer 300 may include a pigment. Graphite composite material (1000, 1000 ') is a heat-dissipating filler may be implemented in a dark or black color as graphite is included in the subject, in this case, the use of the color may be avoided in some applications. Accordingly, the protective coating layer 300 may further include a known pigment to express the desired color.

However, when the thickness of the protective coating layer 300 is thin, there may be a case in which the desired color may not be expressed even when the pigment is added.

Accordingly, according to another embodiment of the present invention, as shown in FIGS. 4 and 5, the graphite composite materials 2000 and 2000 ′ cover the core portions 211 and 221 and the covering portions 212a / 212b and 222a surrounding the core portions 210 and 220. / 222b) is implemented as a polymer matrix (210,220), the core portion (211,221) is provided with a first heat radiation filler (100 '), the coating portion (212a / 212b, 222a / 222b) pigment 400 It can express a desired color different from the color of the core portion including.

The first heat radiation filler 100 'is the same as the description of the heat radiation filler 100 described above and will be omitted.

In addition, the core parts 210 and 220 and the coating parts 212a / 212b and 222a / 222b may be molded by including a thermoplastic polymer compound, for example, may be implemented through double injection. Specifically, first, the core may be injected into a predetermined shape, and then the coating part may be injected to surround the outside of the manufactured core, thereby implementing the polymer matrix. However, the present invention is not limited thereto, and the polymer matrix may be formed by simultaneously injecting the core portion and the coating portion. In this case, the thermoplastic polymer compounds forming the core portions 210 and 220 and the coating portions 212a / 212b and 222a / 222b may be the same or different, and may be changed according to the purpose.

In addition, the coating part 212a / 212b, 222a / 222b may have a thickness of 300 μm to 1 cm to prevent the color of the core parts 210 and 220 from shining out, but is not limited thereto. / Brightness and the type of material of the coating, the content of the pigment included, etc. can be changed.

Since the content of the pigment 400 may vary depending on the type and degree of color to be expressed, the present invention is not particularly limited thereto.

On the other hand, when the thickness of the coating portion 212a / 212b, 222a / 222b becomes thick, the heat dissipation and radiation characteristics of the core portions 211 and 221 may be hindered, so that the coating portions 212a / 212b and 222a / 222b preferably have heat radiation, The second heat radiation filler 500 may be further included to minimize degradation of the radiation characteristics. The second heat dissipation filler 500 may be a known heat dissipation filler, and may further include a known heat dissipation filler of metal, carbon, and / or ceramic. In addition, when insulation is required at the same time, a known insulating heat-radiating filler such as aluminum oxide, boron nitride, talc, magnesium oxide, silicon carbide, or the like may be provided. In addition, since the content of the second heat radiation filler 500 may be appropriately changed in consideration of the content of the pigment in the coating portion, the thickness of the coating portion, the type of the main resin forming the coating portion, the present invention is not particularly limited thereto. .

In addition, a protective coating layer 310 may be further provided outside the coating parts 212a / 212b and 222a / 222b to prevent detachment of the pigment 400, the heat dissipation filler 500, and the like. The protective coating layer 310 is the same as the description of the protective coating layer 300 described above, a detailed description thereof will be omitted.

6A and 6B, the above-described graphite composite 3100 may be implemented as a heat dissipating compound 3000 and 3000 ′ together with the supporting member 3200.

The graphite composite 3100 may exhibit excellent heat dissipation and light weight, but may be limited in some applications when a high level of mechanical strength is required. This has the advantage that the heat dissipation characteristics and mechanical strength can be achieved at the same time by being provided with a support member that can complement the mechanical strength.

The support member 3200 performs a function of expressing a predetermined heat dissipation performance while improving the mechanical strength of the heat dissipation composite material 3000, 3000 ′. The support member 3200 is excellent in compatibility with the above-described polymer matrix and excellent in mechanical strength even at a thin thickness without being easily separated from the interface between the polymer matrix 200 and the support member 3200, and may be injection molded. The material having a degree of heat resistance and at the same time having a predetermined thermal conductivity may be used without limitation. As a non-limiting example, the support member may be a metal, and specifically, may be an alloy including at least one metal selected from the group consisting of aluminum, magnesium, iron, titanium, and copper, or at least one metal. .

In addition, the support member 3200 may have a thickness of 0.5 to 90%, more preferably 3 to 50% of the total thickness of the heat dissipating composite material (3000, 3000 '). If the thickness of the support member 3200 is less than 0.5% of the total thickness of the heat dissipating material, it is difficult to ensure the desired level of mechanical strength and heat dissipation performance. In addition, if it exceeds 90%, it is difficult to express a desired level of heat dissipation performance, and moldability into a complicated shape may also be deteriorated. However, the present invention is not limited thereto, and the thickness of the support member 3200 may be appropriately changed in consideration of the mechanical strength required for the heat dissipating composite.

In addition, the support member 3200 is a plate-like shape having a predetermined width or a plurality of wires or bars are spaced at predetermined intervals inside the rim member having a predetermined shape, such as square or circular, parallel structure, grid structure, honeycomb Structures and shapes having various structures in which they are combined.

The support member 3200 is located inside the polymer matrix of the graphite composite 3100 as shown in Figure 6b to form an interface with the polymer matrix from the front, or the lower surface of the support member 3200 as shown in Figure 6a graphite composite 3100 It can be located so as not to contact the polymer matrix of the.

In addition, the description of the graphite composite material 3100 including the heat dissipation filler 100 is the same as described above, and thus the present invention will be omitted. However, the nanoparticles of the graphite composite provided in the heat dissipation filler 100 may function as anchors as described above to significantly improve the bonding characteristics of the interface between the polymer matrix and the support member and the interface between the graphite and the polymer matrix of the graphite composite. .

In addition, a protective coating layer 3300 may be provided on all or part of an outer surface of the graphite composite material 3100 and the support member 3200 provided to form an interface with the graphite.

Since the protective coating layer 3300 may be a protective coating layer that may be further included on the outer surface of the graphite composite material described above, the present invention will not be described in detail.

The graphite composite and the heat dissipating composite according to the present invention described above may be implemented as an electrical and electronic component. The electric and electronic parts may be parts of electric and electronic devices used in various industries such as battery field, automobile field, lighting field, aerospace field, display field, etc., in particular, a part requiring heat dissipation performance and durability at the same time. Can be. In addition, the graphite composite or heat dissipating composite according to the present invention in the above components can be employed as a heat dissipation housing, heat dissipation support member, heat dissipation circuit board, heat sink. However, the field in which the graphite composite material and the heat dissipation composite material are used, and the specific use thereof are not limited thereto.

Although the present invention will be described in more detail with reference to the following examples, the following examples are not intended to limit the scope of the present invention, which will be construed as to aid the understanding of the present invention.

Example 1

A raw material powder was prepared by mixing a mixing ratio of graphite, which is a plate-shaped expanded graphite having an average particle diameter of 300 μm, and nickel powder at a weight ratio of 1:19 for 10 minutes. In addition, 30 lpm and 50 lpm of argon gas were injected into the high frequency thermal plasma apparatus as the central gas and the cis gas. After applying 17 kW to the plasma torch power to generate a high-temperature thermal plasma, the vacuum of the equipment is maintained at 500 torr before injecting the raw material powder, and the raw powder prepared through the injection nozzle of the plasma generating electrode is a high frequency thermal plasma. Injected into the reaction part, inside the graphite was moved without thermal damage by the plasma, only nickel powder was crystallized into nanoparticles through a selective vaporization process to combine with the graphite. The combined graphite and nickel nanoparticles were combined in the cyclone unit and adsorbed to the collector filter through a transfer pipe, and the powder adsorbed on the filter was collected in the collecting unit through a blowback process.

Thereafter, in order to form a catechol amine layer on the collected binder, 2 mM dopamine was dissolved in TBS (Tris buffer solution, 100 mM), and 5 g of the binder was mixed with 1 L of the solution, followed by stirring at room temperature and atmospheric conditions for 2 hours. It was. In order to increase the reaction rate of the dopamine with the nickel nanoparticles, sodium periodate (Sodium Periodate) was added to 10% of the dopamine weight and stirred. After stirring for 2 hours, the unreacted material was removed by filtration, washed twice with Di-water, and dried at room temperature to prepare a graphite composite coated with polydopamine (hereinafter, referred to as "GC"). In the prepared graphite composite, the weight percentages of graphite, nanoparticles, and polydopamine were 94.95 wt%, 5 wt%, and 0.05 wt%, respectively. In addition, the average particle diameter of the nanoparticles confirmed through the SEM image was 32 nm.

A graphite composition was prepared by mixing the prepared graphite composite and expanded graphite (hereinafter referred to as 'EG' in Tables 1 to 3) in a weight ratio of 1: 9, and then preparing a graphite composition and a thermoplastic polymer polyamide-6 in a weight ratio of 1: 1. After mixing into a main hopper and a site feeder of the coaxial twin screw extruder, and melted under an extruder barrel temperature of 280 ℃ conditions to produce a pellet using the Strand cutting method, and then dried in a hot air dryer to prepare a masterbatch for graphite composites .

<Examples 2 to 18>

The preparation was carried out in the same manner as in Example 1, except that the graphite composition was changed as in Tables 1 to 3 to prepare a masterbatch for graphite composites as shown in Tables 1 to 3 below. In this case, the graphite flakes in Tables 1 to 3 were expressed as "GF", the average particle diameter was used as 75㎛, spherical graphite was expressed as "RG", the average particle diameter was used as 40㎛.

Comparative Example 1

Prepared in the same manner as in Example 1, but did not add graphite to the graphite composition was prepared in the master batch for graphite composites including only graphite composites.

Comparative Example 2

Preparation was carried out in the same manner as in Example 1, but instead of graphite of the graphite composition was added to the same amount of carbon black having an average particle diameter of 330nm to prepare a graphite composite masterbatch.

Experimental Example

After the master batch prepared in Examples and Comparative Examples was put into a conventional injection apparatus to prepare an injection product, the following physical properties were evaluated and the results are shown in Tables 1 to 3. At this time, the size and shape of each injection molded specimen was prepared to suit the evaluation method of the physical properties as follows.

1. Horizontal thermal conductivity

Horizontal thermal conductivity of the specimens was measured according to ASTM E1461.

2. Tensile Strength

Tensile strength on the specimen was measured according to ASTM D638.

3. Impact strength

Impact strength was measured according to ASTM D256.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Graphite Composition GC: graphite weight ratio 1: 9 1: 14.7 1:17 1: 24.5 1:26 1: 3 1: 1.2 Graphite Type and Mix Weight Ratio EG EG EG EG EG EG EG Graphite composites PA-6: Graphite Composition Weight Ratio 1: 1 1: 1 1: 1 1: 1 1: 1 1: 1 1: 1 Horizontal thermal conductivity
(W / mK) 14.2 14.5 14.5 14.7 14.9 13.8 13.9 Tensile Strength (Kgf / ㎠) 855 860 830 810 790 840 830 Impact Strength (Kgf.cm/cm) 3.52 3.53 3.20 3.18 2.58 3.52 3.35

(* GC: Graphite Composite, EG: Expanded Graphite, PA-6: Polyamide-6)

Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Graphite Composition GC: graphite weight ratio 1: 0.7 1: 9 1: 9 1: 9 1: 9 1: 9 1: 9 Graphite Type and Mix Weight Ratio EG GF RF EG + RG
/ 1: 8 EG + GF / 1: 8 EG + GF / 1: 13 EG + GF / 1: 15 Graphite composites PA-6: Graphite Composition Weight Ratio 1: 1 1: 1 1: 1 1: 1 1: 1 1: 1 1: 1 Horizontal thermal conductivity
(W / mK) 14.2 13.20 8.30 9.3 14.8 14.5 13.7 Tensile Strength (Kgf / ㎠) 790 820 670 710 840 855 832 Impact Strength (Kgf.cm/cm) 2.71 2.93 3.62 3.45 3.69 3.60 3.49

(* GC: graphite composite, EG: expanded graphite, GF: graphite flake, RF: spherical graphite, PA-6: polyamide-6)

(* GC: graphite composite, EG: expanded graphite, GF: graphite flake, PA-6: polyamide-6)

As can be seen in Tables 1 to 3,

In the case of Comparative Example 1 containing only the graphite composite, it can be seen that the tensile strength and the impact strength are not significantly better than those having the graphite composite in addition to the other examples.

In addition, Comparative Example 2 containing a carbon material other than the carbon material or graphite can be confirmed that the thermal conductivity is not very good.

Meanwhile, it can be seen that Example 1, which includes expanded graphite in graphite, exhibits excellent thermal conductivity and mechanical strength in comparison with Example 9 including graphite flakes and Example 10 including spherical graphite. It can be seen that there is a synergistic effect in the combination of the composite and expanded graphite.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention may add components within the scope of the same idea. Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also fall within the spirit of the present invention.

100,100 ': heat dissipation filler 101: graphite composite
102,103: graphite 200,210,220: polymer matrix
211,221: core 212a, 212b, 222a, 222b: covering part
300, 310, 3300: protective coating layer 400: pigment
500: second heat radiation filler
1000,1000 ', 2000,2000', 3100: Graphite Composite
3000,3000 ': heat dissipation composite 3200: support member

Claims (17)

A graphite composite in which nanoparticles having a catecholamine layer on a surface thereof are fixed on graphite; And graphite including expanded graphite. The method of claim 1,
The graphite composite and the graphite is a graphite composition is provided in a weight ratio of 1: 1 to 25. The method of claim 1,
The graphite composite further comprises a polymer layer coated on at least the catecholamine layer. The method of claim 1,
The graphite composite has an average particle diameter of 10 ~ 900㎛ graphite composition. The method of claim 1,
The graphite composition further comprises any one or more of graphite flakes and spherical graphite in addition to the expanded graphite. The method of claim 5,
The graphite flakes have an average particle diameter of 10㎛ ~ 1,000㎛, the expanded graphite is an average particle diameter of 50㎛ ~ 1,000㎛, the spherical graphite is an average particle diameter of 10㎛ ~ 100㎛ graphite composition. The method of claim 1,
The graphite further includes graphite flakes,
The expanded graphite and graphite flakes is a graphite composition containing 1: 1 to 20 by weight. The method of claim 2,
The graphite composite and the graphite is a graphite composition is provided in a weight ratio of 1: 1 to 15. The method of claim 7, wherein
The expanded graphite and graphite flakes is a graphite composition comprising 1: 1 to 13 by weight. A graphite composition according to any one of claims 1 to 9; And
Thermoplastic high molecular compound; Masterbatch for producing a graphite composite comprising a. The method of claim 10,
The graphite composition is a master batch for producing a graphite composite is provided with 20 to 80% by weight of the total weight of the masterbatch. The method of claim 10,
The thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystalline polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), A masterbatch for preparing graphite composites, which is one compound selected from the group consisting of acrylonitrile-butadiene-styrene interpolymer (ABS), polyetherimide (PEI) and polyimide, or mixtures or copolymers of two or more thereof. A polymer matrix molded including a thermoplastic polymer compound; And
A graphite composite comprising: a heat dissipation filler comprising the graphite composition according to claim 1 dispersed in the polymer matrix. The method of claim 13,
At least a portion of the outer surface of the polymer matrix graphite composite further provided with a protective coating layer. A polymer matrix molded including a thermoplastic polymer compound to form a core portion and a coating portion surrounding the core portion;
A first heat radiation filler comprising the graphite composition according to claim 1 dispersed in the core portion; And
A graphite composite comprising a pigment dispersed in the interior including the coating. The method of claim 15,
The coating part further comprises a second heat radiation filler. The graphite composite according to any one of claims 13 to 16; And
And a support member provided to form at least one interface with the polymer matrix of the graphite composite material.

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