KR102498309B1 - Composition for manufacturing graphite-polymer composite and graphite composite comprising the same - Google Patents

Abstract

A composition for preparing a graphite-polymer composite is provided. A composition for preparing a graphite-polymer composite according to an embodiment of the present invention is implemented by including a graphite composite including nanoparticles and a catecholamine layer bonded to a graphite surface, a thermoplastic polymer compound, and a strength improving agent. According to this, the composition for preparing a graphite-polymer composite material is uniformly dispersed in the polymer resin to exhibit excellent heat dissipation performance, and at the same time, stability and durability can be secured by supplementing insufficient mechanical strength due to mixing of heterogeneous substrates. In addition, it is very easy to mold when molding through injection/extrusion by being combined with a substrate, and molding into various shapes is possible. The composite material implemented according to this can be widely applied to various technical fields requiring heat dissipation as it exhibits excellent heat dissipation performance, guarantees excellent mechanical strength, is excellent in light weight, and has excellent economic feasibility.

Description

Composition for manufacturing graphite-polymer composite and graphite composite realized thereby

The present invention relates to a composition for preparing a graphite-polymer composite, and more particularly, to implement a polymer composite having excellent light weight and excellent heat dissipation performance, easy injection into various shapes, and improved durability by improving the strength of the injection product. It relates to a composition for preparing a graphite-polymer composite and a graphite composite material realized through the composition.

Heat build-up in electronics, light fixtures, converter housings and other devices that generate unwanted heat 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, the metal part is heavy and has a high production cost.

In recent years, a heat dissipation member manufactured using an injection molding or extrudable polymer resin has been proposed, and many studies have been conducted due to advantages such as lightness and low unit price due to the material characteristics of the polymer resin itself.

The heat dissipation member is provided with a heat dissipation filler in order to express a desired heat dissipation property, and the heat dissipation filler is inevitably different from a polymer resin having a low thermal conductivity in terms of material, and thus a problem arises in compatibility between the dissimilar materials. For example, ideally, uniform dispersion of the functional filler in the polymer resin may be advantageous in terms of heat dissipation performance. However, cutting may occur and the heat dissipation performance may be significantly deteriorated.

In particular, graphite-polymer composites have been introduced as heat-dissipating members to cope with the recent trend of weight reduction and miniaturization of electronic components, but the low strength of graphite-polymer composites also significantly reduces the strength of heat-dissipating members, resulting in poor stability and stability of heat-dissipating members. There is a problem that does not guarantee durability. Furthermore, there is a problem that the moldability is significantly reduced due to the filling of a large amount of heat-radiating filler, which limits the application to various industrial groups.

Accordingly, there is an urgent need to develop a heat-dissipating filler composition capable of implementing a heat-dissipating member that sufficiently exhibits heat dissipation performance at a desired level while securing light weight, has excellent mechanical strength and durability, and is easy to injection mold.

Publication No. 10-2016-0031103

The present invention was devised in view of the above points, and the present invention is uniformly dispersed in a polymer resin to express excellent heat dissipation performance, and at the same time, stability and durability are secured by supplementing insufficient mechanical strength due to mixing of heterogeneous substrates It is an object of the present invention to provide a composition for preparing a graphite-polymer composite.

In addition, another object of the present invention is to provide a composition for preparing a graphite-polymer composite material, in which moldability is improved even during molding through injection/extrusion, etc., and molding into various shapes is possible.

In addition, another object of the present invention is to provide a graphite composite material that exhibits excellent heat dissipation performance, at the same time guarantees excellent mechanical strength, is excellent in lightness, is excellent in economic feasibility, and is realized in various shapes.

In order to solve the above problems, the present invention provides a composition for preparing a graphite-polymer composite including a graphite composite including nanoparticles and a catecholamine layer bonded to a graphite surface, a thermoplastic polymer compound, and a strength improving agent.

According to one embodiment of the present invention, the strength improver may include at least one material selected from the group consisting of carbon fiber, glass fiber, talc, and mica.

In addition, the amount of the carbon fibers may be 1 to 30 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite.

In addition, the glass fibers may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite, have an average diameter of 10 to 14 μm, and have an average length of 3 to 20 mm.

In addition, the talc is included in 5 to 50 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite material, and the particle diameter may be 3 to 50 μm.

In addition, the mica may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite.

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 50 to 600 μm.

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 a mixture or copolymer of two or more.

In addition, it may further include at least one impact modifier selected from the group consisting of thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), maleic acid grafted EPDM, and rubber-based elastic particles, and the impact modifier is a graphite-polymer composite composition for preparing It may be included in 0.1 to 30 parts by weight based on 100 parts by weight.

In addition, at least one additive selected from the group consisting of a dispersing agent, an antioxidant, a work improver, a coupling agent, a flame retardant, a light stabilizer, a heat stabilizer, and a UV absorber may be further included.

In addition, the present invention provides a graphite composite having a body molded of a thermoplastic polymer compound, a graphite composite including nanoparticles and a catecholamine layer bonded to a graphite surface, and a dispersion including a strength improver dispersed in the body.

In addition, according to one embodiment of the present invention, the dispersion may be provided in 10 to 80% by weight of the total weight of the graphite composite.

In addition, a protective coating layer may be further provided on the outer surface of the body.

According to the present invention, the composition for preparing a graphite-polymer composite material is uniformly dispersed in a polymer resin to exhibit excellent heat dissipation performance, and at the same time, stability and durability can be secured by supplementing insufficient mechanical strength due to mixing of heterogeneous substrates. In addition, it is very easy to mold when molding through injection/extrusion by being combined with a substrate, and molding into various shapes is possible. The composite material implemented according to this can be widely applied to various technical fields requiring heat dissipation as it exhibits excellent heat dissipation performance, guarantees excellent mechanical strength, is excellent in light weight, and has excellent economic feasibility.

1 is a diagram of a graphite composite according to an embodiment of the present invention, wherein FIG. 1A is a perspective view of the graphite composite, FIG. 1B is a cross-sectional view along the XX′ boundary of FIG. 1A, and
2 is a cross-sectional view of a graphite composite according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.

A composition for preparing a graphite-polymer composite material according to an embodiment of the present invention is implemented by including a graphite composite thermoplastic polymer compound including nanoparticles and a catecholamine layer bonded to a graphite surface, and a strength improving agent.

First, the graphite composite will be described.

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

The graphite 10 is a mineral in which planar macromolecules, in which 6-membered rings of carbon atoms are infinitely connected in a plane, are layered and superimposed, and may be of a type known in the art, specifically, impression graphite, high crystalline graphite, and earthy graphite It may be either natural graphite or artificial graphite. When the graphite 10 is natural graphite, for example, it may be expanded graphite obtained by expanding impression graphite. The artificial graphite may be prepared through a known method. For example, a thermosetting resin such as polyimide is prepared in the form of a film 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 a hydrocarbon such as methane is thermally decomposed at a high temperature to obtain chemical vapor deposition (CVD) ), it is also possible to manufacture highly oriented graphite.

In addition, 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 atypical shape, and may be a plate shape as an example. In addition, the average particle diameter of the graphite 10 may be 50 to 600 μm, for example, 300 μm, and the graphite 10 may be high-purity graphite having a purity of 99% or more, through which more improved physical properties It may be advantageous to express.

Next, the nanoparticles 20 bonded to the surface of the above-described graphite 10 function as a medium capable of providing the graphite 10 with a catecholamine layer 30 to be described later. Specifically, since the surface of the above-described graphite 10 is rarely provided with functional groups capable of mediating chemical reactions, a catecholamine layer capable of improving the dispersibility of the graphite 10 in heterogeneous materials ( 30) on the surface of the graphite 10, there is a problem in that the amount of catecholamine actually remaining in the graphite is very small even if the graphite is treated with catecholamine. In addition, in order to solve this problem, even if the surface of graphite is modified to have functional groups, there is a limit to increasing the amount of catecholamine provided on the surface of the modified graphite. However, in the case of graphite having nanoparticles on the surface, since catecholamines are easily bonded to the surface of the nanoparticles, a desired amount of catecholamines can be introduced into the graphite.

The nanoparticle 20 may be a metal or non-metal material that exists as a solid at room temperature, and as non-limiting examples thereof, alkali metals, alkaline earth metals, lanthanum groups, actinium groups, transition metals, post-transition metals, It may be selected from metalloids and the like. For example, the nanoparticles may be Ni, Si, Ti, Cr, Mn, Fe, Co, Cu, Sn, In, Pt, Au, Mg, or a combination thereof, and may be Cu, Ni, or Si.

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

In addition, the nanoparticles 20 are preferably in a crystallized particle state, and may be provided to occupy 10 to 70% of the total surface area of each graphite 10, more preferably 30 to 70% of the area. there is. In addition, the nanoparticles 20 may be provided in an amount of 5 to 70% by weight, preferably 20 to 50% by weight, based on the total weight of the graphite composite 101. At this time, the nanoparticles 20 can express a stronger bonding force by forming a chemical bond with the graphite 10.

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

The catecholamine forming the catecholamine layer 30 has a hydroxyl group (-OH) as the ortho-group of the benzene ring and a para-group having various alkylamines. A term meaning a single molecule As non-limiting examples of various derivatives of these structures, dopamine, dopamine-quinone, epinephrine, alpha-methyldopamine, norepinephrine, alpha-methyl It may be alphamethyldopa, droxidopa, indolamine, serotonin, or 5-hydroxydopamine, and the like. As an example, the catecholamine layer 30 is dopamine dopamine) layer. The dopamine is a monomolecular substance having a catechol and an amine functional group and having a molecular weight of 153 (Da). As an example, a substance to be surface modified in an aqueous solution under basic pH conditions (about pH 8.5) containing dopamine represented by Formula 1 below If it is put in and taken out after a certain period of 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 each selected from a thiol, a primary amine, a secondary amine, a nitrile, and an aldehyde. ), imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic ester) or one selected from the group consisting of carboxamide, and the rest may be hydrogen.

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

On the other hand, the polymer layer 40 may be further coated on the catecholamine layer 30, and as compatibility with the polymer compound forming the composite material increases due to the polymer layer 40, further improved fluidity, dispersibility and interface binding properties 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 of this, the thermosetting polymer compound may be one 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. 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 type of compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more types. Alternatively, the polymer layer may be a rubber elastic body including natural rubber and/or synthetic rubber, or similar materials thereof.

The above-described graphite composite 101 may be prepared by preparing a graphite-nanoparticle assembly in which nanoparticles are formed on the graphite surface and forming a catecholamine layer on the graphite-nanoparticle assembly, and the catecholamine layer It can be prepared by further performing the step of further forming a polymer layer after forming.

The step of preparing a graphite-nanoparticle conjugate in which nanoparticles are formed on the surface of graphite according to an embodiment of the present invention can be employed without limitation if it is a known method for forming nanoparticles on the surface of graphite, and is not limited thereto. As an example, existing gas-phase synthesis technologies for producing metal-based nanopowder include inert gas condensation (IGC), chemical vapor condensation (CVC), metal salt spray-drying, etc. method can be employed. However, among them, the inert gas condensation (IGC) process is capable of producing high-purity ultra-fine nanometal powder, but requires a lot of energy and has a very low production rate, which limits industrial applications. Chemical vapor condensation (CVC) The process is slightly improved in terms of energy or production rate compared to the inert gas condensation (IGC) process, but may be uneconomical because the price of precursors, which are raw materials, is very high. In addition, the metal salt spray drying process is economical because it uses cheap salt as a raw material, but it is disadvantageous in terms of environment because contamination and powder aggregation cannot be avoided in the drying step and toxic by-products are generated.

Accordingly, preferably, nanoparticles may be formed on the graphite through atmospheric pressure high-frequency thermal plasma. Specifically, through the steps of mixing graphite and nanoparticle-forming powder, injecting gas into the prepared mixture, vaporizing the nanoparticle-forming material through a high-frequency thermal plasma, and crystallizing the vaporized nanoparticle-forming material on the graphite surface. can be performed

First, in the step of mixing graphite and nanoparticle-forming powder, the mixing ratio between the two materials may be designed differently according to the purpose, and may be mixed using a separate stirrer.

Next, a gas can be injected into the mixed mixture. At this time, the injected gas can be classified into sheath gas, central gas, carrier gas, etc. according to its function, and these gases include inert gases such as argon, hydrogen, nitrogen or A mixture of these gases may be used, and argon gas may be preferably used. The sheath gas is injected to prevent vaporized nanoparticles from adhering to the inner surface of the wall and to protect the wall from ultra-high-temperature plasma, and 30 to 80 lpm (liters per minute) of argon gas may be used. In addition, the central gas is a gas injected to generate a high-temperature thermal plasma, and 30 to 70 lpm argon gas may be used. In addition, the carrier gas serves to supply the mixture into the plasma reactor, and 5 to 15 lpm of argon gas may be used.

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

Next, a step of crystallizing the vaporized nanoparticle-forming material on the graphite surface may be performed. A quenching gas may be used to crystallize the vaporized nanoparticle-forming material on the graphite surface. At this time, crystallization may be performed while inhibiting the growth of nanoparticles by condensing or rapidly cooling with the quenching gas.

Forming a catecholamine layer on the graphite-nanoparticle conjugate prepared by the above method may be performed, and specifically, dipping the graphite-nanoparticle conjugate in a 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 a tris buffer solution (10 mM, tris buffer solution) of pH 8 to 14, more preferably pH 8.5 basic Tris buffer solution, which is the same basic condition as the underwater environment. It may be prepared by dissolving dopamine in a buffer solution, and at this time, 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 spontaneously polymerizes under basic and oxidative conditions to form a catecholamine layer, which is a polydopamine layer, on the graphite-nanoparticle conjugate. At this time, an oxidizing agent may be further provided to form a polydopamine layer, and oxygen gas in the air may 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 polydopamine 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, in order to form a catecholamine layer with a thickness of 5 to 100 nm, it is 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 a catecholamine layer may be formed on the nanoparticles due to the nanoparticles. On the other hand, dipping is exemplified as the above-described method for forming the polymer layer, but is not limited thereto, and blade coating, flow coating, casting, printing method, transfer method, brushing, or spraying A polymer layer may be further formed through a known method such as spraying.

On the other hand, in order to further provide a polymer layer to the graphite composite having a catecholamine layer, the graphite composite having a polymer layer may be prepared by mechanically mixing the graphite composite with a solution in which a desired polymer compound is dissolved or a molten liquid.

On the other hand, since the above-described graphite composite is produced by firing at a high temperature, it is resistant to heat and has excellent elasticity compared to general carbon. In particular, the thermal conductivity (500 W / mL) of the graphite composite is superior to that of conventional silver (400 W / mL), copper (390 W / mL), and aluminum (230 W / mL), and in the longitudinal direction perpendicular to the conventional heat dissipation member In the heat transfer form, heat transfer in the transverse direction is possible according to the structural characteristics of graphite, so there is an advantage of very excellent heat dissipation characteristics. In addition, since graphite is advantageous in lightweight screens due to its unique light weight, it can respond to the recent trend of thinning, ultra-small and lightweight electronic products, and attempts to use it as a heat dissipation member are continuing.

However, in order to use the excellent heat dissipation characteristics of the graphite composite, mixing with a polymer compound is required, and at this time, problems such as fluidity, dispersibility, and bonding characteristics of the interface may occur due to the difference in physical properties between the graphite composite and the polymer compound. . In particular, since the inherent mechanical strength of each graphite composite and polymer compound affects the mechanical strength of the graphite-polymer composite in which they are mixed, durability and stability can be ensured in order to use the graphite-polymer composite as a heat dissipation member in various industries. Therefore, mechanical strength improvement of the graphite-polymer composite must be preceded.

Accordingly, the present invention can solve the above problems by realizing a composition for preparing a graphite-polymer composite in which the above-described graphite composite is mixed with a polymer compound and a strength improver, and the strength improver will be described first.

The strength improving agent is mixed with the graphite composite and the polymer compound, and serves to improve the mechanical strength of the graphite-polymer composite material implemented as a composition for preparing the graphite-polymer composite material. Specifically, the strength improver improves the yield strength, tensile strength, ductility, toughness and strength of the graphite-polymer composite so that the graphite-polymer composite can withstand plastic deformation or cracking, thereby improving durability and stability as a heat dissipation member of electronic products. can be guaranteed

In addition, the strength improving agent may be used without limitation in the case of a known component capable of improving the mechanical strength of a composite material between graphite and a polymer compound, and as non-limiting examples thereof, carbon fibers, glass fibers, glass beads, zirconium oxide , wollastonite, gibbsite, boehmite, magnesium aluminate, dolomite, calcium carbonate, magnesium carbonate, mica, talc, silicon carbide, kaolin, calcium sulfate, barium sulfate, silicon dioxide, ammonium hydroxide, magnesium hydroxide and hydroxide One or more components selected from the group consisting of aluminum may be included as a strength improving agent, and preferably one or more materials selected from the group consisting of carbon fiber, glass fiber, talc, and mica may be included.

For example, when the strength improver is implemented by including carbon fiber, it may be included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite. If the carbon fiber is included in less than 1 part by weight, it is difficult to improve the mechanical strength of the graphite-polymer composite as desired, and if the carbon fiber is included in more than 30 parts by weight, the mechanical strength can be greatly improved. However, due to the insufficient content of the graphite composite and the polymer compound, heat dissipation properties are deteriorated, molding is difficult, and problems in terms of durability and dimensional stability may occur due to the fact that the strength improver is not uniformly dispersed.

At this time, when the strength improver is implemented by including carbon fiber, an electromagnetic wave shielding effect due to the inherent physical properties of carbon fiber can also be expected as an additional effect. Electromagnetic wave shielding is to prevent malfunctions of electronic products by blocking electromagnetic waves generated from electronic products and external electromagnetic waves. Since it is a technology that has recently become an issue in the electronics industry along with heat dissipation characteristics, the strength improver includes carbon fiber, so that two The availability of the graphite-polymer composite according to the present invention, which has the same effect, can be greatly improved.

As another example, when the strength improving agent is implemented by including glass fibers, it may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite. If the glass fiber is included in an amount of less than 5 parts by weight, it is difficult to improve the mechanical strength of the graphite-polymer composite as desired, and if the glass fiber is included in an amount of more than 30 parts by weight, the mechanical strength can be greatly improved. However, due to the insufficient content of the graphite composite and the polymer compound, heat dissipation properties are lowered, molding is difficult, and problems in terms of durability and dimensional stability may occur due to the fact that the strength improving agent is not uniformly dispersed.

In addition, the glass fibers may have an average diameter of 10 to 14 mm and an average length of 3 to 20 mm. In the case of using glass fibers outside the above range, there is a concern that mechanical strength may be lowered rather due to partial cracks or cracks occurring due to glass fibers hindering the uniform dispersion of the composition for preparing a graphite-polymer composite. In addition, due to this, the heat dissipation characteristics are lowered, and use as a desired heat dissipation member may be restricted.

As another example, the strength improving agent may be implemented by including talc and mica. The talc is generally used as a heat dissipation filler because of its relatively high thermal conductivity, and its utilization in the field of electronic products is increasing due to its unique insulating properties. In particular, since the structural form of talc has a plate-like shape, the mechanical strength of graphite-polymer composites can be greatly improved, and furthermore, it is chemically very stable and hardly causes chemical change even when mixed with other materials, so the graphite-polymer composites It can also contribute to improving chemistry.

Since the mica has a relatively high aspect ratio, excellent tensile strength and bending strength, and high heat deflection temperature, the mechanical strength of the graphite-polymer composite material according to the present invention can be greatly improved. In the present invention, the mica is pulverized and used in the form of powder, but is not limited thereto and may be used in various forms within a range that satisfies the effect of improving the strength of mica.

The talc and mica are included in 5 to 50 parts by weight based on 100 parts by weight of the composition for preparing a graphite-polymer composite material, and implemented in the form of a powder having a particle size of 3 to 50 μm and included in the strength improving agent. If the talc and mica are included in less than 5 parts by weight, there is a problem that the mechanical strength improvement of the composition for preparing a graphite-polymer composite is insignificant and cannot be used as a target industrial group, and if the talc and mica are included in more than 50 parts by weight In this case, the uniform dispersibility of the composition for preparing a graphite-polymer composite may be hindered, and cracks and cracks may occur in a specific part.

Next, the thermoplastic polymer compound may be a known thermoplastic polymer compound, and may be a material forming a body of a graphite composite material to be described later. The thermoplastic polymer compound is preferably polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone ( PES), polyetherimide (PEI), and a compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more kinds. 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), keyana, 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-based compound such as polyethylene, polypropylene, polystyrene, polyisobutylene, or ethylene vinyl alcohol.

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 type, so the present invention is not particularly limited thereto.

Meanwhile, the composition for preparing a graphite-polymer composite according to an embodiment of the present invention includes at least one impact modifier selected from the group consisting of thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), maleic acid-grafted EPDM, and rubber-based elastic particles. It can be implemented further including.

The impact modifier can be used without limitation in the case of a known component capable of improving impact resistance by expressing flexibility and stress relaxation of a composite material between graphite and a polymer compound, for example, thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), maleic acid grafted EPDM, core/shell structured elastic particles, and rubber-based resin may be provided as an impact modifier. The thermoplastic polyolefin is a group of materials similar to rubber, and is a linear polyolefin block copolymer having a polyolefin block and a rubbery block such as polypropylene or polyethylene, or a blend of polypropylene with an ethylene-based elastomer, ethylene-propylene-diene monomer (EPDM) And, since known thermoplastic polyolefins can be used, the description of specific types thereof is omitted in the present invention. In addition, since known thermoplastic polyurethanes can also be used, descriptions of specific types are omitted. In addition, for the core/shell structured elastic particle, for example, an allyl-based resin may be used for the core, and the shell portion is a polymer having a functional group capable of reacting to increase compatibility and bonding force with a thermoplastic polymer compound. It may be resin.

On the other hand, the composition for preparing a graphite-polymer composite according to another embodiment of the present invention is selected from the group consisting of an antioxidant, a heat stabilizer, a light stabilizer, a plasticizer, an antistatic agent, a work improver, a UV absorber, a dispersing agent, a coupling agent, a dispersing agent, and a flame retardant. It may be implemented by further including one or more additives.

The antioxidant is provided to prevent breaking of the main chain of the thermoplastic polymer compound due to shear during extrusion and injection, and to prevent thermal discoloration. As the antioxidant, known antioxidants may be used without limitation, and as non-limiting examples thereof, tris (nonyl phenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2 organophosphites 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 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; Distearylthiopropionate, dilaurylthiopropionate, ditridecylthiopropionate, octadecyl-3-(3,5-di-tert-butyl-l-4-hydroxyphenyl)propionate , esters of thioalkyl or thioaryl compounds such as pentaerythrityl-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 heat stabilizer may be used without limitation in the case of a known heat stabilizer, but as non-limiting examples thereof, 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 as non-limiting examples thereof, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5 benzotriazoles such as -tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxy benzophenone or the like or mixtures thereof. Light stabilizers can generally be included at 0.1 to 1.0 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

In addition, the plasticizer may be used without limitation in the case of known plasticizers, but as non-limiting examples thereof, dioctyl-4,5-epoxy-hexahydrophthalate, tris-(octoxycarbonylethyl) isocyanurate, phthalic acid esters such as tristearin, epoxidized soybean oil or the like, or mixtures thereof. 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, as the antistatic agent, known antistatic agents may be used without limitation, and as non-limiting examples thereof, glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzenesulfonate, polyether block amides, or mixtures thereof, including, for example, BASF under the tradename Irgastat; Arkema under the trade name PEBAX; and from Sanyo Chemical industries under the trade name Pelestat. The antistatic 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 work improver may use a known work improver without limitation, and as non-limiting examples thereof, metal stearate, stearyl stearate, pentaerythritol tetrastearate, beeswax, montan wax (montan wax), paraffin wax, polyethylene wax or the like or mixtures thereof. The work improver 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, as the UV absorber, known UV absorbers may be used without limitation, and non-limiting examples thereof include 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-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 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, known dispersants and coupling agents may be used without limitation as the dispersing agent and coupling agent, and maleic acid-grafted polypropylene, silane-based coupling agents, and the like may be used for heat resistance as non-limiting examples of the coupling agent.

In addition, the flame retardant is, for example, a halogenated flame retardant, similar tetrabromo bisphenol A oligomers such as BC58 and BC52 (like tretabromo bisphenol A oligomers), brominated polystyrene or poly(dibromo-styrene), brominated epoxy, Decabromodiphenylene oxide, pentabromobenzyl acrylate monomer, pentabromobenzyl acrylate polymer, ethylene-bis(tetrabromophthalimide, bis(pentabromobenzyl)ethane, Mg(OH) ₂ and Al( Metal hydroxides such as OH) ₃ , melamine cyanurate, 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 diphenylsulfonesulfonate and sodium- or potassium-2,4,6,-trichlorobenzoate and N-(p- tolylsulfonyl)-p-toluenesulfimide potassium salt, N-(N'-benzylaminocarbonyl) sulfanylimide potassium salt, or mixtures thereof.

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

As shown in FIG. 2, the graphite composite 1000 is implemented as a body 200 and a dispersion 100 according to the present invention dispersed inside the body, and a protective coating layer 300 is formed on the outer surface of the body This may be further provided.

The graphite composite 101 and the strength improver 102 in the dispersion 100 are shown as being dispersed only inside the body in FIG. 2, but unlike FIG.

The dispersion 100 may be provided in an amount of 10 to 80% by weight based on the total weight of the graphite composite 1000. If the dispersion 100 is provided in less than 10% by weight, the desired heat dissipation and shielding performance may not be exhibited. In addition, if it is provided in excess of 80% by weight, the mechanical strength of the composite material is significantly lowered, moldability such as injection is lowered, and it may be difficult to implement it into a complex shape.

The body 200 is formed of the above-described thermoplastic polymer compound, and a detailed description thereof is omitted as it is the same as that described above.

The protective coating layer 300 serves to protect the body from external physical/chemical stimuli and to prevent detachment of the graphite composite 101 and the strength improver 102 provided in the body. In addition, when the protective coating layer 300 is made of an insulating material, it can also play a role of providing insulation that can be used as a heat dissipation member of an electronic device requiring insulation at the same time.

The protective coating layer 300 may be implemented with a known thermosetting polymer compound or thermoplastic polymer compound. The thermosetting polymer compound may be one 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 kinds. 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 a mixture or copolymer of two or more, but is not limited thereto.

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

On the other hand, the protective coating layer may further include a known heat radiation filler in order to express more improved heat radiation and heat radiation characteristics into the outside air. In addition, when insulation is required at the same time, a known insulating heat dissipating filler such as aluminum oxide, boron nitride, talc, magnesium oxide, or the like may be provided.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention may add elements within the scope of the same spirit. However, other embodiments can be easily proposed by means of changes, deletions, additions, etc., but these will also fall within the scope of the present invention.

100: dispersion
101: graphite composite
102: strength improver
200: body 300: protective coating layer

Claims (16)

A graphite composite comprising nanoparticles and a catecholamine layer bonded to a graphite surface;
thermoplastic high molecular compounds; and
A strength improver comprising glass fibers having an average diameter of 10 to 14 μm and an average length of 3 to 20 mm, and talc and mica having a particle diameter of 3 to 50 μm; including,
The glass fiber is included in 5 to 30 parts by weight based on 100 parts by weight of the total composition,
The talc and mica are included in 5 to 50 parts by weight based on 100 parts by weight of the total composition. A composition for preparing a graphite-polymer composite. delete delete delete According to claim 1,
The catecholamine layer is provided on at least the surface of the nanoparticles,
The graphite composite further comprises a polymer layer coated on at least the catecholamine layer. A composition for preparing a graphite-polymer composite. According to claim 1,
0.1 to 30 parts by weight of at least one impact modifier selected from the group consisting of thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), maleic acid-grafted EPDM, and rubber-based elastic particles, based on 100 parts by weight of the composition for preparing graphite-polymer composites Graphite further comprising a composition for preparing a polymer composite. A body molded from a thermoplastic polymer compound; and
A graphite composite containing nanoparticles and catecholamine layer bonded to the surface of graphite, glass fibers having an average diameter of 10 to 14 μm and an average length of 3 to 20 mm, and talc and mica having a particle diameter of 3 to 50 μm. a dispersion dispersed in the body including a strength improving agent; to provide,
It is formed of a composition for preparing a graphite-polymer composite including the thermoplastic polymer compound and the dispersion,
A graphite composite material comprising 5 to 30 parts by weight of the glass fiber and 5 to 50 parts by weight of the talc and mica, based on 100 parts by weight of the composition for preparing the graphite-polymer composite. According to claim 7,
The dispersion is a graphite composite material provided in 10 to 80% by weight of the total weight of the graphite composite material. According to claim 7,
A graphite composite wherein a protective coating layer is further provided on the outer surface of the body. delete delete delete delete delete delete delete

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