KR20190018228A - Composition for manufacturing graphite-polymer composite and Graphite-polymer composites comprising the same - Google Patents

Abstract

The present invention provides a composition for manufacturing a graphite-polymer composite. According to an embodiment of the present invention, the composition for manufacturing a graphite-polymer composite comprises: a heat radiation filler having a graphite composite including a catecholamine layer and nanoparticles coupled to the surface of graphite; a matrix-forming component including a thermoplastic polymer compound; and an additive including a coupling agent. Accordingly, dispersion and interfacial adhesion between the polymer compound and the heat radiation filler are improved, and degradation in heat radiation performance and mechanical properties is minimized to secure stability and durability. Also, the composition can be combined with a base material to facilitate injection/extrusion molding. Forming into various shapes is possible. The realized composite exhibits excellent heat radiation performance, secures excellent mechanical strength, is very lightweight, and has excellent economic efficiency to be widely applied to various technical fields requiring heat radiation.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for producing a graphite-polymer composite, and a graphite-

The present invention relates to a composition for preparing a graphite-polymer composite material, and more particularly, to a composition for preparing a graphite-polymer composite material which improves the interfacial adhesion and dispersibility of a heterogeneous material and does not deteriorate heat radiation performance and mechanical properties. The present invention relates to a graphite-polymer composite material.

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

In recent years, a heat dissipating member made of a polymer resin capable of being injection molded or extruded has been proposed, and a lot of research is continuing due to advantages such as light weight and low cost due to the material characteristics of the polymer resin itself.

The heat dissipation member is provided with a heat dissipation pillar for exhibiting a desired heat dissipation property. However, the heat dissipation pillar is inevitably different from a polymeric resin having a low thermal conductivity on a material, and problems arise in compatibility between dissimilar materials. For example, ideally, the uniform distribution of the functional filler in the polymer resin may be advantageous in terms of heat dissipation performance, but in reality, the functional filler is more likely to be concentrated and distributed in a specific position of the polymer resin, And heat dissipation performance due to the problem of dispersibility in which cutting is generated may be remarkably deteriorated.

In addition, since the heat-radiating filler has a high viscosity in a molten state, impregnation into the polymer resin is difficult, and the low surface free energy of the heat-radiating filler deteriorates the interfacial adhesion with the polymer resin. Separation phenomenon may occur. This interfacial separation phenomenon may cause deterioration of the heat dissipation characteristics and mechanical properties of the heat dissipation member as well as the deterioration of the dispersibility described above. Therefore, many attempts have been made to improve the interfacial adhesion between the heat dissipation filler and the polymer resin.

For example, oxidation treatment, plasma treatment, and whisker-zation treatment of the surface of a heat-radiating filler have been introduced, but the interfacial adhesion between the heat-radiating filler and the polymer resin is improved only by surface treatment of the heat- And there is a fear that the dispersibility may be deteriorated through the treatment of different kinds of substances. Further, since the chemical treatment may affect the heat radiation performance of the heat-radiating filler, the heat radiation performance and the mechanical properties are not deteriorated At the same time, studies are urgently needed to improve the interfacial adhesion and dispersibility of the heat-radiating filler and the polymer resin.

Japanese Patent Application Laid-Open No. 10-2016-0031103

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to improve the interfacial adhesion force and the fracture property between the polymer resin and the heat-radiating filler and to minimize the deterioration of heat radiation performance and mechanical properties, Which is suitable for producing a graphite-polymer composite material, which is suitable for producing a graphite-polymer composite material.

Another object of the present invention is to provide a composition for the production of a graphite-polymer composite which can be molded by various molding methods such as injection / extrusion and is easily formed into a molded article having various shapes.

In addition, the present invention provides a graphite composite material that exhibits excellent heat dissipation performance through the composition for preparing a graphite-polymer composite as described above, has excellent mechanical strength, is excellent in light weight, is economical, and is realized in various shapes There is another purpose.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a heat spreader comprising a heat-dissipating filler comprising a graphite composite including nanoparticles and a catecholamine layer bonded to a graphite surface, a matrix-forming component comprising a thermoplastic polymer compound and an additive comprising a coupling agent A composition for producing a graphite-polymer composite is provided.

According to an embodiment of the present invention, the coupling agent may be a silane coupling agent, a maleic acid graft polypropylene (MAH-g-PP), or a maleic acid grafted EPDM (MAH-g-EPDM).

The maleic acid graft polypropylene may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

The maleic acid grafted EPDM may be contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the total thermoplastic polymer compound.

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

In addition, the graphite composite may have an average particle size of 50 to 600 탆.

The thermoplastic polymer compound may be at least one selected from the group consisting of polyamides, polyesters, polyketones, liquid crystal polymers, polyolefins, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphenylene oxide (PPO) ), A polyetherimide (PEI), and a polyimide, or a mixture or copolymer of two or more thereof.

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

The present invention also provides a master batch for the production of the graphite-polymer composite in which the above-described composition for preparing a graphite-polymer composite is molded.

The present invention also relates to a heat spreader comprising a heat dissipation filler having a graphite composite including a nanoparticle and a catecholamine layer bonded to a graphite surface, an additive including a coupling agent and a thermoplastic polymer compound, wherein the heat dissipation filler and the additive are dispersed A graphite-polymer composite including a polymer matrix is provided.

The heat-radiating filler may be contained in an amount of 10 to 90% by weight based on the total weight of the graphite-polymer composite material.

The outer surface of the polymer matrix may further include a protective coating layer.

According to the present invention, stability and durability can be secured by improving the interfacial adhesion force and dispersibility between the polymer compound and the heat-radiating filler, and minimizing the heat radiation performance and the deterioration of the mechanical properties. In addition, it is very easy to form during molding by injection / extrusion combined with a base material, and molding into various shapes is possible. Accordingly, the composite material can be widely applied to a variety of technical fields requiring heat dissipation as it exhibits excellent heat dissipation performance, has excellent mechanical strength, is excellent in light weight, and is excellent in economy.

1 is a perspective view of a graphite composite according to an embodiment of the present invention. FIG. 1B is a sectional view taken along a line X-X 'in FIG. 1A,
2 is a cross-sectional view of a graphite-polymer composite according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

The composition for preparing a graphite-polymer composite according to an embodiment of the present invention includes a heat dissipation filler comprising a graphite composite including nanoparticles and a catecholamine layer bonded to graphite surface, a matrix forming component including a thermoplastic polymer compound, and a coupling agent ≪ / RTI >

First, a heat dissipation filler having a graphite composite will be described.

The heat dissipation filler 101 having the graphite composite includes nanoparticles 20 and a catecholamine layer 30 bonded to the surface of the graphite 10 as shown in Figs. 1A and 1B, and the polymer layer 40 ). ≪ / RTI >

The graphite 10 may be of a kind known in the art as a layered superposition of a planar macromolecule in which a hexagonal ring of carbon atoms is infinitely connected in layers and specifically includes graphite, high crystalline graphite and graphite Or natural graphite or artificial graphite. When the graphite 10 is natural graphite, for example, it may be expanded graphite expanded graphite. The artificial graphite may be one produced by a known method. For example, a thermosetting resin such as polyimide is produced in a film shape of 25 μm or less and then graphitized at a high temperature of 2500 ° C. or higher to produce a monocrystalline graphite, or a hydrocarbon such as methane is pyrolyzed at a high temperature, ) To produce a highly oriented graphite.

The shape of the graphite 10 may be a known shape such as a spherical shape, a plate shape or a needle shape, or an irregular shape, for example, a plate shape. The graphite 10 may be an ultra-pure graphite having a purity of 99% or more. The graphite 10 may have an improved physical property Lt; / RTI >

Next, the nanoparticles 20 bonded to the surface of the graphite 10 described above function as a medium capable of providing the graphite 10 with a catecholamine layer 30 to be described later. In detail, since the functional group capable of mediating a chemical reaction is hardly provided on the surface of the graphite 10, the catecholamine layer (hereinafter referred to as " catecholamine ") capable of improving the dispersibility in the different materials of the graphite 10 30) is not easily provided on the surface of the graphite 10, even when the catecholamine is treated with graphite, the amount of the catecholamine remaining in the graphite is very small. Further, in order to solve this problem, there is a limit to increase the amount of catecholamine present on the surface of the modified graphite even if the modification treatment is carried out so as to have a functional group on the surface of the graphite. However, in the case of graphite having nanoparticles on its surface, there is an advantage that catecholamines can be introduced into the graphite by the desired amount as they are easily bonded onto the surface of the nanoparticles.

The nanoparticles 20 may be a metal or a non-metal material that is solid at room temperature, and examples thereof include alkali metals, alkaline earth metals, lanthanides, actinides, transition metals, Semi-metals 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.

The nanoparticles 20 may have an average particle diameter of 10 to 500 nm, preferably 10 to 100 nm.

In addition, the nanoparticles 20 may be provided in an amount of 10 to 70% area, more preferably 30 to 70% of the entire surface area of the individual graphite 10, have. The nanoparticles 20 may be present in an amount of 5 to 70% by weight, preferably 20 to 50% by weight based on the total weight of the heat dissipation pillars 101 having the graphite composite. At this time, the nanoparticles 20 are chemically bonded to the graphite 10 to exhibit stronger binding force.

Next, the catecholamine layer 30 may be provided on at least the surface of the nanoparticles 20 described above. Through this, the catecholamine layer 30 can be formed on the surface of the nanoparticles 20, and the flowability, dispersibility, The interface coupling property can be improved. In addition, the catecholamine layer 30 itself has a reducing power, and amine functional groups in the catechol functional groups of the layer surface form covalent bonds by the Michael addition reaction. Thus, the catecholamine layer 30 is subjected to secondary surface modification For example, as a bonding material capable of introducing the polymer layer 40 into the graphite in order to exhibit further improved dispersibility in the polymer compound.

The catecholamine forming the catecholamine layer 30 is an ortho-group of the benzene ring, a term having a hydroxy group (-OH) and having a variety of alkylamines in the para-group Non-limiting examples of various derivatives of such structures include but are not limited to dopamine, dopamine-quinone, epinephrine, alphamethyldopamine, norepinephrine, For example, alphamethyldopa, droxidopa, indolamine, serotonin or 5-hydroxydopamine, and the catecholamine layer 30 may be 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, dopamine may be added to an aqueous solution of basic pH (about pH 8.5) containing dopamine represented by the following formula And after a certain period of time, a polydopamine (pDA) coating layer may be formed on the surface of the material by oxidation of the catechol.

[Chemical Formula 1]

At least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ in Formula 1 is a thiol, a primary amine, a secondary amine, a nitrile, an aldehyde Imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic acid, and the like. ester) or carboxamide (carboxamide), and the remainder may be hydrogen.

The thickness of the catecholamine layer 30 may be 5 to 100 nm, but is not limited thereto.

The polymer layer 40 may be further coated on the catecholamine layer 30 and the compatibility with the polymer compound forming the composite material may be increased due to the polymer layer 40, Coupling characteristics can be implemented. The polymer layer 40 may be formed of a thermosetting polymer compound or a thermoplastic polymer compound, and the specific types of the thermosetting polymer compound and the thermoplastic polymer compound may be known ones. As a non-limiting example, the thermosetting polymer compound may be a compound selected from the group consisting of epoxy-based, urethane-based, ester-based and polyimide-based resins, or a mixture or copolymer of two or more thereof. The thermoplastic polymer compound may be at least one selected from the group consisting of polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphenylene oxide (PPO), polyether sulfone Polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more kinds thereof. Alternatively, the polymer layer may be a rubber elastomer including natural rubber and / or synthetic rubber, and the like.

The heat dissipation filler 101 having the above-described graphite composite may be manufactured by preparing a graphite-nanoparticle conjugate in which nanoparticles are formed on the graphite surface and forming a catecholamine layer on the graphite-nanoparticle conjugate And forming the catecholamine layer, followed by further forming a polymer layer.

The step of preparing the graphite-nanoparticle conjugate having the nanoparticles formed on the surface of the graphite according to an embodiment of the present invention can be adopted without limitation as long as it is a known method of forming nanoparticles on the graphite surface. In this example, conventional gas phase synthesis techniques for producing metal nanopowders include inert gas condensation (IGC), chemical vapor condensation (CVC), metal salt spray-drying Can be employed. However, the inert gas condensation (IGC) process can produce very fine nano metal powders with high purity. However, it requires a large energy and has a very low production rate, which limits the industrial application, and chemical vapor condensation (CVC) The process may be somewhat improved in terms of energy or production rate compared to the inert gas condensation (IGC) process, but it may be uneconomical because the cost of the precursor, the raw material, is very high. In addition, the metal salt spray drying process is economical because it uses an inexpensive salt as a raw material, but contamination at the drying stage and agglomeration of the powder can not be avoided and toxic by-products are generated, which is disadvantageous from the environmental viewpoint.

Preferably, nanoparticles can be formed on the graphite through an atmospheric pressure high-frequency thermal plasma. Specifically, the step of mixing the graphite and the nanoparticle-forming powder includes the steps of injecting gas into the prepared mixture, vaporizing the nanoparticle-forming material through the high-frequency thermal plasma, and crystallizing the vaporized nanoparticle-forming material on the graphite surface .

Next, the gas mixture can be injected into the mixed mixture, and the injected gas can be classified into a sheath gas, a central gas, a carrier gas and the like depending on its function. These gases include an inert gas such as argon, hydrogen, A gas obtained by mixing these gases may be used, and preferably argon gas may be used. The sheath gas is injected to prevent vaporized nanoparticles from adhering to the inner surface of the wall and also to protect the wall surface from ultrahigh plasma. Argon gas of 30 to 80 lpm (liters per minute) can be used. In addition, the central gas is a gas which is injected to generate a high-temperature thermal plasma, and argon gas of 30 to 70 lpm can be used. Further, the carrier gas serves to supply the mixture into the plasma reactor, and argon gas of 5 to 15 lpm can be used.

Next, the nanoparticle-forming material can be vaporized through a high-frequency thermal plasma. The thermal plasma is an ionization gas composed of electrons, ions, atoms and molecules generated from a plasma torch using DC arc or high frequency inductively coupled discharge, and is a high-speed jet having a very high temperature and high activity ranging from several thousands to several tens of thousands K . Accordingly, in order to smoothly generate high-temperature plasma, a power of 10 to 70 kW is supplied to the power supply of the plasma apparatus, an arc is formed by electric energy, and argon gas used as a thermal plasma generating gas is used to generate about 10,000 K ultra-high-temperature plasma is generated. As described above, the ultra-high temperature thermal plasma generated by using argon gas as a gas while maintaining a power of 10 to 70 kW is 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 appropriately modify and use a known high-frequency thermal plasma (RF) method, and a conventional thermal plasma processing apparatus may be used.

Next, a step of crystallizing the vaporized nanoparticle-forming material on the graphite surface can be performed. In order to crystallize the vaporized nanoparticle-forming material on the graphite surface, quenching gas may be used. At this time, the quenching gas may be condensed or quenched to crystallize while suppressing the growth of nanoparticles.

The step of forming a catecholamine layer on the graphite-nanoparticle binder prepared by the above-described method may be performed. Specifically, dipping the graphite-nanoparticle binder into a weakly basic dopamine aqueous solution may be performed. And forming a poly-dopamine layer on the surface of the graphite-nanoparticle conjugate.

First, the method for preparing the weakly basic dopamine aqueous solution is not particularly limited. However, the method of preparing the weak basic dopamine aqueous solution is not particularly limited, but a pH 8 to 14 basic tris buffer solution (10 mM, tris buffer solution), more preferably a basic pH 8.5 basic tris The dopamine concentration of the weakly basic dopamine aqueous solution may be 0.1 to 5 mg / ml, preferably 2 mg / ml, by dissolving dopamine in the buffer solution.

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

At this time, the dipping time determines the thickness of the polypodamine layer. In the case of using a dopamine aqueous solution having a pH of 8 to 14 and a dopamine concentration of 0.1 to 5 mg / ml, it is preferable to form a catecholamine layer with a thickness of 5 to 100 nm It is preferable to dip for 0.5 to 24 hours. Pure plate-like graphite can hardly form a dopamine coating layer on the graphite surface through such a method, but the catecholamine layer can be formed on the nanoparticles due to the nanoparticles. However, the present invention is not limited to the dipping method. For example, a blade coating, a flow coating, a casting, a printing method, a transfer method, a brushing, A polymer layer may be further formed by a known method such as spraying.

On the other hand, in order to further provide a polymer layer on the graphite composite having the catecholamine layer formed thereon, a graphite composite in which a polymer layer is formed can be produced by mechanically mixing a graphite composite with a dissolution solution or a molten melt in which a desired polymer compound is dissolved.

Next, the matrix forming component including the thermoplastic polymer compound may include a known thermoplastic polymer compound, and may be a material forming the body of a graphite-polymer composite material described later. The thermoplastic polymer compound is preferably selected from the group consisting of polyamides, polyesters, polyketones, liquid crystal polymers, polyolefins, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphenylene oxide (PPO) PES), polyetherimide (PEI), and polyimide, or a mixture or copolymer of two or more kinds thereof. The polyamide may be a known polyamide compound such as nylon 6, nylon 66, nylon 11, nylon 610, nylon 12, nylon 46, nylon 9T (PA-9T), kiana and aramid.

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

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

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

Next, additives including the coupling agent will be described.

The coupling agent serves to improve the interfacial adhesion between the graphite composite and the polymer compound.

On the other hand, since the above-described graphite composite is produced by calcination at a high temperature, it is more resistant to heat and superior in elasticity than ordinary carbon. In particular, the thermal conductivity (500 W / mL) of the graphite composite is superior to the conventional silver (400 W / mL), copper (390 W / mL) and aluminum (230 W / mL) It is possible to make the heat transfer in the lateral direction according to the structural characteristics of the graphite in the heat transfer form of the graphite. In addition, since it is advantageous in a lightweight screen due to light weight specific to graphite, it is possible to respond to the trend of thinning, super-size and light weight of electronic products in recent years, and thus it has been attempted to use this as a heat radiating filler.

At this time, the graphite composite is mixed with a polymer compound that can be formed into a molded product, and is realized as a heat-radiating filler. The carbon material such as the graphite composite may be produced by van der Waals force due to intermolecular van der Waals force Since agglomeration can occur, studies on dispersibility are necessary

Particularly, the problem of the interfacial adhesion between the graphite composite and the polymer compound affects the direct physical properties such as the above-mentioned dispersibility, the fluidity in the polymer compound of the heat-radiating filler and the bonding property with the polymer compound, The improvement of the interfacial adhesion between the graphite composite and the polymer compound is a technical problem that must be preceded in the heat dissipating member including the graphite composite and the polymer compound because it can directly or indirectly affect the heat radiation performance and the mechanical properties .

In order to improve the interfacial adhesion, a method of modifying the surface of a polymer matrix formed of a graphite composite or a polymer compound has been introduced. However, the physical properties of the graphite composite as a heat-radiating filler can be influenced by a chemical / , The heat radiating performance and the mechanical properties of the heat dissipating member implemented through the heat dissipating member may be affected. In other words, it is urgently required to study additives that can provide a good interfacial adhesion to the surface of a graphite composite or a polymer matrix and uniformly disperse in a polymer compound, thereby preventing deterioration of heat dissipation performance and mechanical properties and assuring chemical stability and durability. to be.

Accordingly, the composition for preparing a graphite-polymer composite according to the present invention comprises a heat dissipation filler having the above-described graphite composite and a coupling agent as an additive, wherein the coupling agent is a silane coupling agent, a maleic acid graft polypropylene (MAH- (MAH-g-PP), maleic acid grafted EPDM (MAH-g-EPDM), preferably maleic acid grafted polypropylene Can be implemented.

The maleic acid graft polypropylene (MAH-g-PP) can be represented by the following formula (1).

[Chemical Formula 1]

The maleic anhydride graft polypropylene (MAH-g-PP) represented by the above formula (1) can form a crosslinking site with the surface of the graphite composite by increasing the compatibility of the maleic anhydride with the polar group, And serves to increase dispersibility. In addition, the maleic acid graft polypropylene (MAH-g-PP) has excellent chemical resistance, which is not denatured by oxidation or ozone because of a relatively low degree of unsaturation, and has stable insulating properties even at high temperatures.

In addition, it has a high compatibility with a polymer resin due to the hydrophobic property of the polymerized propylene moiety, and has an advantage in terms of insolubility and chemical resistance that do not react with other functional additives. Furthermore, it has an advantage that injection moldability and reproducibility of a graphite-polymer composite realized with a polymer compound and a graphite composite are excellent because of excellent injection properties.

At this time, the maleic acid graft polypropylene (MAH-g-PP) may have a predetermined weight average molecular weight. If the weight average molecular weight of the maleic acid graft polypropylene (MAH-g-PP) is excessively low, the content of the maleic anhydride graft polypropylene (MAH-g-PP) in the composition for preparing a graphite composite is insufficient, The adhesive property may not be expressed as desired.

The maleic acid graft polypropylene (MAH-g-PP) may be contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. If the maleic acid graft polypropylene (MAH-g-PP) is contained in an amount of less than 0.1 part by weight, the improvement in the interfacial adhesion property to be achieved through the maleic acid graft polypropylene (MAH-g-PP) If the maleic acid graft polypropylene (MAH-g-PP) is used in an amount exceeding 30 parts by weight, the uniform dispersibility in the polymer compound may be degraded, and the heat dissipation performance and mechanical properties of the resultant graphite- It may cause deterioration of physical properties.

The coupling agent according to another embodiment of the present invention may be embodied as maleic acid graft EPDM (MAH-g-EPDM).

EPDM may be prepared by copolymerizing ethylene, propylene, and a diene. The EPDM according to an embodiment of the present invention may include an unsaturated carboxylic acid or a derivative thereof (ester, acid anhydride, salt, acid halide, Amide, imide, etc.) or other functional groups. Examples of the unsaturated carboxylic acid or derivative thereof include acrylic acid, methacrylic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, ) Glycidyl acrylate, and maleic acid ester, and their structures such as an ester salt and a metal salt can also be used. However, it is preferable to use acrylic acid, methacrylic acid and maleic anhydride as the unsaturated carboxylic acid or its derivative, and it is most preferable to use maleic anhydride.

At this time, the modification of EPDM through the unsaturated carboxylic acid or its derivative can be carried out by heating and mixing in the presence of a graft polymerization initiator. The diene in the EPDM used as the raw material is preferably 5-ethylidene-2-norbornene, Dicyclopentadiene, 1,4-hexadiene and the like can be used.

The maleic anhydride-graft modified EPDM can increase the compatibility by forming a cross-linking point with the surface of the graphite composite, such as maleic anhydride-grafted polypropylene (MAH-g-PP) And it plays a role of increasing the bonding force and dispersibility with the graphite composite. Also, it has excellent chemical resistance, insulation property, injection moldability and reproducibility similar to the above-mentioned maleic acid graft polypropylene (MAH-g-PP).

At this time, the maleic anhydride-grafted EPDM may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. If the maleic anhydride-grafted EPDM is contained in an amount of less than 0.1 part by weight based on 100 parts by weight of the thermoplastic polymer compound, the desired interfacial adhesive strength and dispersibility may not be improved. If the maleic anhydride graft- When the EPDM is contained in an amount of more than 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound, the uniform dispersibility in the polymer compound may be deteriorated. As a result, the heat dissipation performance and the mechanical properties of the resultant graphite- .

In the maleic anhydride-grafted EPDM, the copolymerization weight ratio of ethylene, propylene and diene is such that the maleic anhydride-grafted EPDM maintains the impact resistance described above, and the graphite- It is not particularly limited as long as it can be appropriately selected so as not to deteriorate the mechanical properties and heat radiation performance of the polymer composite.

In addition, the composition for preparing a graphite-polymer composite according to an embodiment of the present invention may contain additives such as impact modifiers, flame retardants, strength improvers, antioxidants, heat stabilizers, light stabilizers, plasticizers, antistatic agents, And at least one additive selected from the group consisting of

The impact modifier can be used without limitation in the case of known components capable of improving impact resistance by exhibiting flexibility and stress relaxation property of a composite material between graphite and a polymer compound. Examples of the impact modifier include thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), maleic acid grafted EPDM, elastic particles of a core / shell structure, and a rubber-based resin as an impact modifier. The thermoplastic polyolefin is a material group similar to a rubber, and is a linear polyolefin block copolymer having a polyolefin block such as polypropylene or polyethylene and a rubbery block, or an ethylene-propylene-diene monomer (EPDM) And specific thermoplastic polyolefins can be used as known ones. Thus, the description of specific types of the present invention will be omitted. Further, since the thermoplastic polyurethane can be a known one, the description of the specific kind is omitted. As the elastic particles of the core / shell structure, for example, an allyl resin may be used for the core, and a shell portion may be formed of a polymer having a functional group capable of reacting with the thermoplastic polymer compound Resin.

Such flame retardants include, for example, halogenated flame retardants, like terebromo bisphenol A oligomers such as BC58 and BC52, brominated polystyrene or poly (dibromo-styrene), brominated epoxy, Bis (pentabromobenzyl) ethane, Mg (OH) _2, and Al (OH) ₂ , ethylene-bis (tetrabromophthalimide, bis metal such as a _three hydroxide, melamine cyanurate, red phosphorus (red phosphorus) and a phosphor-based FR system, melamine polyphosphate, phosphate ester, metal phosphinate, ammonium polyphosphate, expandable graphite, sodium same Or potassium perfluorobutane sulfate, sodium or potassium perfluorooctane sulfate, sodium or potassium diphenyl P-toluenesulfonimide and sodium- and potassium-2,4,6-trichlorobenzoate and N- (p-tolylsulfonyl) -p-toluenesulfimide phthanium salt, N- (N'-benzylaminocarbonyl ) Sulfanyl imide potassium salt, or a mixture thereof. The flame retardant may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

The strength modifier can be used without limitation in the case of a known component capable of improving the strength of the composite material between the graphite and the polymer compound. As a non-limiting example, carbon fibers, glass fibers, glass beads, zirconium oxide, Mica, talc, silicon carbide, kaolin, calcium sulfate, barium sulphate, silicon dioxide, ammonium hydroxide, magnesium hydroxide and aluminum hydroxide, and mixtures thereof. One or more components selected from the group consisting of the above-mentioned components may be included as the strength improver. The strength improver may be included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the graphite composition, but is not limited thereto. For example, when the strength modifier is glass fiber, the diameter of the glass fiber may be 2 to 8 mm.

The antioxidant is provided to prevent breakage of the main chain of the thermoplastic polymer compound due to shearing at the time of extrusion and injection, and to prevent heat discoloration. The antioxidant may be any known antioxidant without limitation, including but not limited to tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis , 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 else similar; The butylated reaction product of para-cresol or dicyclopentadiene; Alkylated hydroquinone; Hydroxide thiodiphenyl ether; Alkylidene-bisphenol; Benzyl compounds; Esters of monohydric or polyhydric alcohols with beta - (3,5-di-tert-butyl-4-hydroxyphenyl) -propionic acid; Esters of monohydric or polyhydric alcohols with beta - (5-tert-butyl-4-hydroxy-3-methylphenyl) -propionic acid; (3,5-di-tert-butyl-l-4-hydroxyphenyl) propionate, ditallowyl thiopropionate, ditridecyl thiopropionate, octadecyl 3- Esters of thioalkyl or thioaryl compounds such as pentaerythritol 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 present in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the thermoplastic polymer.

The heat stabilizers may be used without limitation in the case of known heat stabilizers, but as a non-limiting example, triphenyl phosphite, tris- (2,6-dimethylphenyl) phosphite, tris- (mixed mono- Organic phosphites such as tris- (mixed mono-and di-nonylphenyl) phosphate or the like; Dimethylbenzene phosphonate, or other similar phosphonates, trimethylphosphates, or other similar phosphates, or mixtures thereof. The heat stabilizer may be contained in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

The light stabilizers may be used without limitation in the known light stabilizers. For example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2- Benzotriazole and 2-hydroxy-4-n-octoxybenzophenone or the like, or mixtures thereof. The light stabilizer may generally be included in an amount of 0.1 to 1.0 part by weight based on 100 parts by weight of the total composition excluding all the fillers.

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

The antistatic agent may be selected from known antistatic agents without limitation, including, but not limited to, glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzene sulfonate, polyether block Amides, or mixtures thereof, including, for example, BASF from Irgastat under the trade designation Irgastat; Arkema of the trade name PEBAX; And from Sanyo Chemical industries of Pelestat under the trade designation < RTI ID = 0.0 > of Pelestat. ≪ / RTI > The antistatic agent may be contained in an amount of 0.1 to 1.0 part by weight based on 100 parts by weight of the thermoplastic polymer compound.

As the non-limiting examples of the working improving agent, there may be mentioned metal stearate, stearyl stearate, pentaerythritol tetrastearate, beeswax, montan wax, wax, paraffin wax, polyethylene wax or the like, or a mixture thereof. The working modifier may be included in an amount of 0.1 to 1.0 part by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the UV absorber can be any known UV absorber without limitation, including, but not limited to, 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); Bis [[(2-cyano-3,3-biphenylacryloyl) oxy] -2,2-bis [ Methyl] propane; 2,2 '- (1,4-phenylene) bis (4H-3,1-benzoxazin-4-one); Bis [(2-cyano-3,3-diphenylacryloyl) oxy] -2,2-bis [ Methyl] propane; Nano-sized inorganic materials such as titanium oxide, cerium oxide and zinc oxide having a particle size of less than 100 nm; Or the like, or mixtures thereof. The UV absorber may be contained in an amount of 0.01 to 3.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

The dispersing agent and coupling agent may be any known dispersing agent and coupling agent. For example, a maleic acid grafted polypropylene, a silane coupling agent, or the like may be used for heat resistance as a non-limiting example of a coupling agent.

Meanwhile, the composition for preparing a graphite-polymer composite according to an embodiment of the present invention is implemented as a master batch for producing a graphite composite material together with a thermoplastic polymer compound.

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

2, the graphite-polymer composite material 1000 includes a polymer matrix 200 and a dispersed heat-radiating filler 101 and a coupling agent 102, which are dispersed in the polymer matrix 200, And a protective coating layer 300 may be further provided on the outer surface of the polymer matrix 200. Although the coupling agent 102 is shown as an ellipse, it may vary depending on the weight average molecular weight and the polymer shape of the coupling agent 102 to be used, and it is difficult to accurately measure the coupling agent 102, But is not limited to.

2, the heat dissipation pillars 101 and the coupling agent 102 are dispersed only in the polymer matrix 200, but they may be arranged to be exposed to the outer surface differently from FIG.

The heat-radiating filler 101 may be 10 to 90% by weight based on the total weight of the graphite-polymer composite material 1000. If the heat dissipation filler 101 is less than 10% by weight, the desired heat dissipation and shielding performance may not be exhibited. In addition, if it is contained in an amount exceeding 80% by weight, the mechanical strength of the composite material is remarkably lowered, the moldability such as injection is reduced, and it may be difficult to realize a complicated shape.

The polymer matrix 200 is formed of the thermoplastic polymer compound described above, and a detailed description thereof will be omitted since they are the same as those described above.

The protective layer 300 may be further provided on the outer surface of the polymer matrix 200. The protective coating layer 300 prevents the release of the heat-dissipating filler 101 located on the surface of the polymer matrix, prevents scratches due to physical stimuli applied to the surface, provides an insulating function according to the material, It is possible to make it possible to use it in an application field of an electronic device or the like required simultaneously.

The protective coating layer 300 may be formed of a known thermosetting polymer compound or a thermoplastic polymer compound. The thermosetting polymer compound may be one kind of compound selected from the group consisting of epoxy type, urethane type, ester type and polyimide type resins, or a mixture or copolymer of two or more kinds. The thermoplastic polymer compound may be at least one selected from the group consisting of polyamides, polyesters, polyketones, liquid crystal polymers, polyolefins, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphenylene oxide (PPO) ), A polyetherimide (PEI), and a polyimide, or a mixture or copolymer of two or more kinds, but is not limited thereto.

The protective coating layer 300 may have a thickness of 0.1 to 1000 탆, but the protective coating layer 300 may be modified according to the purpose.

On the other hand, the protective coating layer 300 may interfere with the radiation of heat in the air. The protective coating layer 300 may be a heat-dissipating coating layer further including a heat-radiating filler, in order to exhibit more improved heat radiation, particularly radiation characteristics of heat to the outside air. The heat-radiating filler can be used without limitation in the case of a known heat-radiating filler. If the insulation is simultaneously required, at least one insulating heat-radiating filler selected from the group consisting of aluminum oxide, boron nitride, talc, magnesium oxide, silicon carbide, .

The kind, particle diameter, content, etc. of the heat-radiating filler provided in the protective coating layer 400 may be designed differently according to the purpose, and thus the present invention is not particularly limited thereto.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

101: heat dissipation filler having a graphite composite
102: coupling agent
200: polymer matrix 300: protective coating layer

Claims (13)

A heat dissipation filler comprising a graphite composite comprising nanoparticles and a catecholamine layer bonded to the graphite surface;
A matrix forming component comprising a thermoplastic polymer compound; And
An additive comprising a coupling agent; Based on the total weight of the composition. The method according to claim 1,
Wherein the coupling agent is a silane coupling agent, maleic acid graft polypropylene (MAH-g-PP), or maleic acid grafted EPDM (MAH-g-EPDM). 3. The method of claim 2,
Wherein the maleic acid graft polypropylene (MAH-g-PP) is contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. 3. The method of claim 2,
Wherein the maleic acid grafted EPDM is contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the total thermoplastic polymer compound. The method according to claim 1,
Wherein the catecholamine layer is provided on at least the surface of the nanoparticles. The method according to claim 1,
Wherein the graphite composite further comprises at least a polymer layer coated on the catecholamine layer. The method according to claim 1,
Wherein the graphite composite has an average particle size of 50 to 600 占 퐉. The method according to claim 1,
The thermoplastic polymer compound may be at least one selected from the group consisting of polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphenylene oxide (PPO), polyether sulfone A composition for producing a graphite-polymer composite, which is a compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more thereof. The method according to claim 1,
Wherein the additive further comprises at least one additive selected from the group consisting of a flame retardant, a strength improver, a dispersant, an antioxidant, a work improving agent, a coupling agent, a light stabilizer, a heat stabilizer and a UV absorber. A master batch for the production of a graphite-polymer composite molded from the composition for preparing a graphite-polymer composite according to any one of claims 1 to 9. A heat dissipation filler comprising a graphite composite comprising nanoparticles and a catecholamine layer bonded to the graphite surface;
An additive comprising a coupling agent; And
A polymer matrix formed of a thermoplastic polymer compound and having the heat dissipation filler and the additive dispersed therein; Based on the total weight of the graphite-polymer composite. 12. The method of claim 11,
Wherein the heat-radiating filler comprises 10 to 90% by weight of the total weight of the graphite-polymer composite material. 12. The method of claim 11,
And a protective coating layer is further provided on an outer surface of the polymer matrix.

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