KR102463358B1 - Composition for manufacturing graphite-polymer composite and Graphite-polymer composites comprising the same - Google Patents

Abstract

A composition for preparing a graphite-polymer composite is provided. A composition for producing 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 a graphite surface, a matrix-forming component including a thermoplastic polymer compound, and an antioxidant It is implemented by including additives. According to this, stability and durability can be guaranteed by preventing oxidation of the polymer compound, improving the utilization of the intrinsic properties of the polymer compound, and minimizing deterioration of heat dissipation performance and mechanical properties. In addition, it is very easy to mold when molding through injection/extrusion, etc. in combination with a substrate, and molding into various shapes is also possible. The resulting composite material exhibits excellent heat dissipation performance and at the same time guarantees excellent mechanical strength, has excellent lightness, and is economical, so it can be widely applied to various technical fields requiring heat dissipation.

Description

Composition for manufacturing graphite-polymer composite and graphite-polymer composites comprising the same

The present invention relates to a composition for producing a graphite-polymer composite, and more particularly, to a composition for producing a graphite-polymer composite, which can prevent deterioration and discoloration of properties by preventing oxidation of a polymer compound during the molding process, and a graphite-polymer embodied therein It's about composites.

Heat build-up in electronics, light fixtures, converter housings and other unwanted heat generating devices can severely limit product life and reduce operating efficiency. Metals, which are good conductors of heat, have traditionally been used for thermal management devices such as heat sinks and heat exchangers. However, the metal part has a problem of heavy weight and high production cost.

Accordingly, recently, a heat dissipation member manufactured using injection molding or extrudable polymer resin has been proposed, and many studies are being conducted due to advantages such as light weight and low unit price due to the material properties of the polymer resin itself.

The heat dissipation member is provided with a heat dissipation filler in order to express a desired heat dissipation property. The heat dissipation filler is inevitably different from a polymer resin having a low thermal conductivity in terms of material, thereby causing a problem in compatibility between different materials. For example, ideally, it may be advantageous for the functional filler to be uniformly dispersed in the polymer resin in terms of heat dissipation performance. However, the heat dissipation performance may be significantly reduced due to the problem of dispersibility caused by cutting.

On the other hand, a general thermoplastic polymer resin may react with oxygen present in the air during the molding process to change the physical properties of the polymer resin through oxidation. That is, in the process of extruding and molding a polymer resin to be applied to a desired industrial group, an alkyl radical is generated by heat or mechanical shearing force of the polymer resin, which in turn reacts with oxygen to generate an oxidizing radical. These radicals cause crosslinking reaction, thermal decomposition reaction, and chain scission reaction in the polymer resin, thereby lowering the elasticity of the polymer resin or changing the physical properties of the highly branched resin itself, thereby impairing the utilization of the intrinsic properties of the polymer resin. Furthermore, this may cause a decrease in the quality of the manufactured product.

Accordingly, attempts are being made to prevent the oxidation of the thermoplastic polymer resin to maintain the properties of the polymer resin as it is. However, there is an urgent need for research to improve the usability of polymer resins in various industries by using the properties of polymer resins as they are.

Laid-open Patent Publication No. 10-2016-0031103

The present invention was devised in consideration of the above points, and the present invention prevents oxidation of the polymer compound during the molding process, thereby improving the utilization of the intrinsic physical properties of the polymer compound, and at the same time minimizing the deterioration of heat dissipation performance and mechanical properties. , It is an object of the present invention to provide a composition for producing a graphite-polymer composite suitable for producing a graphite-polymer composite material with guaranteed stability and durability.

In addition, another object of the present invention is to provide a composition for manufacturing a graphite-polymer composite material that can be molded by various molding methods such as injection/extrusion and can be easily molded into a molded body having various shapes.

In addition, the present invention provides a graphite composite material that exhibits excellent heat dissipation performance and at the same time guarantees excellent mechanical strength, has excellent lightness, is economical, and is implemented in various shapes through the above graphite-polymer composite manufacturing composition. There is another purpose.

In order to solve the above problems, the present invention provides an additive comprising a heat dissipation 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 antioxidant; It provides a composition for producing a graphite-polymer composite comprising a.

In addition, according to an embodiment of the present invention, the antioxidant may include a primary antioxidant and a secondary antioxidant.

In addition, the antioxidant is included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound, and the primary antioxidant and the secondary antioxidant may have a weight ratio of 1: 0.1 to 2.0.

In addition, the primary antioxidant may be phenolic (phenol).

In addition, the secondary antioxidant may be a phosphite-based (phosphate) or a thiol-based (thiol).

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) ), polyetherimide (PEI), and one compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more.

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

In addition, the present invention provides a master batch for producing a graphite-polymer composite material, in which the above-described graphite-polymer composite production composition is molded.

In addition, the present invention is molded with a heat dissipation filler having a graphite composite including nanoparticles and a catecholamine layer bonded to the graphite surface, an additive containing an antioxidant, and a thermoplastic polymer compound, and the heat dissipation filler and the additive are dispersed therein. Provided is a graphite-polymer composite including a polymer matrix.

In addition, the heat dissipation filler may be included in an amount of 10 to 90% by weight based on the total weight of the graphite-polymer composite.

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

According to the present invention, stability and durability can be ensured by preventing oxidation of the polymer compound, thereby improving the utility of the intrinsic properties of the polymer compound, and minimizing deterioration of heat dissipation performance and mechanical properties. In addition, it is very easy to mold when molding through injection/extrusion, etc. in combination with a substrate, and molding into various shapes is also possible. The resulting composite material exhibits excellent heat dissipation performance and at the same time guarantees excellent mechanical strength, has excellent lightness, and is economical, so it can be widely applied to various technical fields requiring heat dissipation.

1 is a view of a graphite composite according to an embodiment of the present invention, Figure 1a is a perspective view of the graphite composite, Figure 1b is a view showing a cross-sectional view along the X-X' boundary of Figure 1a, and,
Figure 2 is a graphite according to an embodiment of the present invention - a cross-sectional view of the polymer composite material.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain 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.

The composition for producing 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 a graphite surface, a matrix-forming component including a thermoplastic polymer compound, and an antioxidant It is implemented by including additives.

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

The heat dissipation filler 101 having the graphite composite includes, as shown in FIGS. 1A and 1B , nanoparticles 20 and a catecholamine layer 30 bonded to the graphite 10 surface, and a polymer layer 40 ) may be further included.

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 on top of each other, and may be of a type known in the art, specifically, impression graphite, highly crystalline graphite and earth graphite. It may be any one of 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 a film shape of 25 μm or less and graphitized at a high temperature of 2500° C. or higher to produce single-crystal graphite, or a hydrocarbon such as methane is thermally decomposed at a high temperature to form a chemical vapor deposition method (CVD). ) to produce 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, for example. In addition, the average particle diameter of the graphite 10 may be 50 ~ 600㎛, for example, may be 300㎛, the graphite 10 may be a high-purity graphite with a purity of 99% or more, through this, 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, the catecholamine layer ( 30) is not easy to provide on the surface of the graphite 10, so even if the catecholamine is treated on the graphite, the amount of catecholamine actually remaining in the graphite is very small. In addition, in order to solve this problem, there is a limit in increasing the amount of catecholamines provided on the surface of the modified graphite even if the modification treatment is performed so that functional groups are provided on the surface of the graphite. However, in the case of graphite provided with nanoparticles on the surface, there is an advantage that catecholamines can be introduced into the graphite in a desired amount as catecholamines are easily bound on the surface of the nanoparticles.

The nanoparticles 20 may be a metal or non-metal material that exists as a solid at room temperature, and non-limiting examples thereof include alkali metals, alkaline earth metals, lanthanides, actinides, 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, and combinations thereof, preferably 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 an area of 10 to 70%, more preferably 30 to 70% of the total surface area of individual graphite 10 . have. 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 heat dissipation filler 101 including the graphite composite. At this time, the nanoparticles 20 may 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 nanoparticles 20 described above, and through this, excellent fluidity and dispersibility of graphite in a heterogeneous polymer compound to be described later, and between the graphite complex and the polymer compound It is possible to improve the interfacial bonding properties. In addition, the catecholamine layer 30 has a reducing power by itself and at the same time forms a covalent bond with the amine functional group to the catechol functional group on the surface of the layer by Michael addition reaction, so that the catecholamine layer is used as an adhesive material for secondary surface modification This is possible, for example, it can act as a bonding material that can introduce the polymer layer 40 into the graphite in order to express more improved dispersibility in the polymer compound.

The catecholamine forming the catecholamine layer 30 is an ortho-group of a benzene ring having a hydroxyl group (-OH), and a para-group is a term meaning a single molecule having various alkylamines. As a non-limiting example of various derivatives of this construct, dopamine, dopamine-quinone, epinephrine, alpha-methyldopamine, norepinephrine, alpha-methyl Dopa (alphamethyldopa), droxidopa (droxidopa), indolamine (indolamine), serotonin (serotonin) or 5-hydroxydopamine (5-Hydroxydopamine), etc. may be, for example, the catecholamine layer 30 is dopamine ( dopamine) layer. The dopamine is a monomolecular substance having a molecular weight of 153 (Da) having a catechol and an amine functional group. As an example, a substance to be surface-modified in an aqueous solution of basic pH conditions (about pH 8.5) containing dopamine represented by the following Chemical Formula 1 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 a thiol, a primary amine, a secondary amine, a nitrile, an aldehyde, respectively ), imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic ester 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 to 100 nm, but is not limited thereto.

On the other hand, the polymer layer 40 may be further coated on the catecholamine layer 30, and as the compatibility with the polymer compound forming the composite material increases due to the polymer layer 40, the fluidity, dispersibility and interface are further improved. The 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, 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 types. The thermoplastic polymer compound is polyamide, polyester, polyketone, liquid crystal polymer, polyolefin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenylene oxide (PPO), polyether sulfone (PES), It may be one compound selected from the group consisting of polyetherimide (PEI) and polyimide, or a mixture or copolymer of two or more. Alternatively, the polymer layer may be a rubber elastomer including natural rubber and/or synthetic rubber and a similar material thereof.

The heat dissipation filler 101 having the above-described graphite composite may be manufactured including the steps of: preparing a graphite-nanoparticle composite in which nanoparticles are formed on the graphite surface and forming a catecholamine layer on the graphite-nanoparticle composite. And, after forming the catecholamine layer, it can be prepared by further performing the step of further forming a polymer layer.

The step of preparing a graphite-nanoparticle conjugate in which nanoparticles are formed on a graphite surface according to an embodiment of the present invention may be employed without limitation if it is a known method for forming nanoparticles on a graphite surface, and there is no limitation thereto As an example, conventional gas phase synthesis technologies for manufacturing metal-based nanopowders 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 ultra-fine nano-metal powder with high purity, but it requires a lot of energy, and the production rate is very low, so there is a limit to industrial application, and chemical vapor condensation (CVC) The process is somewhat improved in terms of energy and production rate compared to the inert gas condensation (IGC) process, but it may be uneconomical because the price of a precursor, a raw material, is very high. In addition, the metal salt spray drying process is economical because cheap salt is used as a raw material, but pollution and agglomeration of the powder cannot be avoided in the drying step, and toxic by-products are generated, which is disadvantageous in terms of environment.

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

Next, a gas may be injected into the mixed mixture, and the injected gas may be classified into a sheath gas, a central gas, a carrier gas, etc. according to its function, and these gases include an inert gas such as argon, hydrogen, nitrogen, or A gas mixture thereof may be used, and argon gas may be preferably used. The sheath gas is injected to prevent adhesion of vaporized nanoparticles to the inner surface of the wall and to protect the wall surface 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 of argon gas may be used. In addition, the carrier gas is a gas serving to supply the mixture into the plasma reactor, and 5 to 15 lpm of argon gas may be used.

Next, the nanoparticle-forming material can be vaporized through high-frequency thermal plasma. The thermal plasma is an ionizing gas composed of electrons, ions, atoms and molecules generated by a plasma torch using a direct current arc or high-frequency inductively coupled discharge. . Accordingly, 10 to 70 kW of power is supplied to the power supply device of the plasma device in order to smoothly generate high-temperature plasma, an arc is formed by electric energy, and approximately 10,000 by argon gas used as a thermal plasma generating gas An ultra-high temperature plasma of K is generated. As described above, the ultra-high temperature thermal plasma generated by using argon gas as the generating gas while maintaining the power of 10 to 70 kW has the effect of being generated at a higher temperature than the thermal plasma generated by the heat treatment method or the combustion method. In this case, the present invention can be used by appropriately modifying 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 may be performed. In order to crystallize the vaporized nanoparticle-forming material on the graphite surface, a quenching gas may be used. At this time, it can be crystallized while suppressing the growth of nanoparticles by condensing or quenching with the quenching gas.

The graphite prepared by the method described above may perform the step of forming a catecholamine layer on the nanoparticle conjugate, specifically, dipping the graphite-nanoparticle conjugate in a weakly basic aqueous dopamine 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) with a pH of 8 to 14 basic, more preferably a basic tris with a pH of 8.5 that is the same basic condition as the marine environment It can be prepared by dissolving dopamine in a buffer solution, and in this case, 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 into the prepared weakly basic dopamine aqueous solution, dopamine undergoes a spontaneous polymerization reaction under basic and oxidizing conditions to form a catecholamine layer, which is a polydopamine layer, on the graphite-nanoparticle conjugate. In this case, a polydopamine layer may be formed by further providing an oxidizing agent, 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 an aqueous dopamine 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. In pure plate-like graphite, a dopamine coating layer is hardly formed 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 a method of forming the polymer layer described above, but is not limited thereto, and blade coating, flow coating, casting, printing method, transfer method, brushing, or spraying. The 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 in which the catecholamine layer is formed, the graphite composite in which the polymer layer is formed can be prepared by mechanically mixing the graphite composite in a solution or a molten solution in which a desired high molecular compound is dissolved.

Next, the matrix-forming component including the thermoplastic polymer compound may include a known thermoplastic polymer compound, and graphite, which will be described later, may be a material forming the body of the polymer composite material. 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 one compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more. 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), Kiana and aramid.

For example, the polyester may be a known polyester-based 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 of a known type, so that the present invention is not particularly limited thereto.

On the other hand, since the above-mentioned graphite composite is manufactured by being fired at a high temperature, it has characteristics of being strong in heat and excellent in 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), According to the structural characteristics of graphite in the form of heat transfer, heat transfer in the lateral direction is possible, which has the advantage of very excellent heat dissipation properties. In addition, it is advantageous in a lightweight screen due to its unique light weight, so it can respond to the recent trend of thinning, ultra-small and light weight of electronic products, and attempts to use it as a heat dissipation filler are continuing.

At this time, the graphite composite is mixed with a high molecular compound that can be manufactured into a molded product and is implemented as a heat dissipation filler. The high molecular compound generally reacts with radicals generated during the molding process and oxygen in the air to change properties due to oxidation. have. Therefore, in various industrial fields using polymer compounds, oxidation is prevented through various additives in order to utilize the physical properties of the polymer compounds as they are.

However, in the case of a high molecular compound mixed with a graphite composite as a heat dissipation filler as in the present invention, it is necessary to use a special antioxidant in order to prevent the above-described oxidation without reducing the dispersibility between the graphite composite and the high molecular compound. That is, the development of antioxidants that can improve moldability and product reliability at the same time by not causing an additional chemical reaction with the graphite composite without interfering with the moldability of the high molecular compound is heat dissipation implemented including the graphite composite and the high molecular compound It is a technical task that must be preceded in absence.

Accordingly, the graphite-polymer composite manufacturing composition according to the present invention includes an antioxidant as a heat dissipation filler and an additive having the above-described graphite composite, and the antioxidant may be implemented including a primary antioxidant and a secondary antioxidant have.

The primary antioxidant is also called a free radical scavenger because it reacts with radicals generated by heat or mechanical shear during the molding process of the polymer compound to stabilize the polymer compound, and more specifically, the primary antioxidant is This hydrogen is released to stabilize the radicals generated during the molding process of the polymer compound and turns itself into a radical. As such, it serves to prevent further oxidation. In addition, the polymer compound is stabilized due to the radical chain reaction inhibitory effect of the primary antioxidant, so that better dispersibility can be maintained even when the functional additive is mixed with the polymer compound.

Examples of the primary antioxidant include phenolic antioxidants, monophenolic antioxidants, bisphenolic antioxidants, polymeric phenolic antioxidants and amine antioxidants. In particular, it is preferable to use the phenolic antioxidant because the phenolic antioxidant is excellent in the effect of consuming by reacting with the polymer radical generated by the decomposition of the polymer chain and the peroxide radical by the automatic cycle addition reaction.

In this case, the primary antioxidant may be included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. If the primary antioxidant is included in less than 1 part by weight, the primary antioxidant may not sufficiently react with the alkyl radicals generated during the molding process of the polymer compound, and thus the efficiency of inhibiting the radical chain reaction may be reduced, and if 30 When included in excess of parts by weight, dispersion is not made sufficiently in the polymer compound, and there may be problems in mixing with other functions and additives.

The secondary antioxidant functions as a protective agent to prevent decomposition of the polymer by heat and shear, and a phosphate or thiol antioxidant may be used. The secondary antioxidant serves as an auxiliary to the primary antioxidant by reducing the residual component of the primary antioxidant and the peroxide generated by the primary antioxidant.

Meanwhile, the secondary antioxidant may also serve to prevent discoloration of the polymer compound. For example, when a phenol-based antioxidant is used as the primary antioxidant, the polymer compound is discolored (yellowed) by the reaction with nitrogen oxide (NOx) in the atmosphere at the amount of the phenol-based antioxidant or under high-temperature firing conditions. Problems may arise. In this case, the secondary antioxidant prevents discoloration by inhibiting the reaction between the polymer compound and nitrogen oxide, and serves to ensure excellent reproducibility of the final product.

In addition, the secondary antioxidant may be included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. If the secondary antioxidant is included in an amount of less than 1 part by weight, the residual component of the primary antioxidant and the peroxide generated by the primary antioxidant may not be sufficiently reduced, so that the desired antioxidant effect may not be obtained, and rather There is a possibility that the dispersibility in the polymer compound may be lowered. In addition, if the secondary antioxidant is included in excess of 30 parts by weight, the dispersion in the polymer compound is not sufficient due to the excessive content of the secondary antioxidant, and there may be problems in mixing with other functions and additives. can

On the other hand, it is preferable to use the above-mentioned primary antioxidant and secondary antioxidant together at the same time rather than using them alone. By improving the usability and dispersibility at the same time to minimize the deterioration of the heat dissipation performance and mechanical properties of the final product, the stability and durability can be greatly improved.

In this case, the antioxidant including the primary and secondary may be included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound. If the antioxidant is included in less than 1 part by weight based on the thermoplastic polymer compound, the content of the antioxidant is insignificant and it may not be possible to prevent deterioration or discoloration of the polymer compound through the desired amount of oxidation inhibition. When the antioxidant is included in excess of 30 parts by weight based on the thermoplastic polymer compound, the content of the antioxidant is excessive, and uniform dispersion with the polymer compound and other functional additives may be reduced, and unreacted oxidation as an antioxidant As the inhibitor is eluted, the durability and heat dissipation performance of the product using the same may be reduced.

In addition, the primary antioxidant and the secondary antioxidant may have a weight ratio of 1: 0.1 to 2.0. If the primary antioxidant and the secondary antioxidant have a weight ratio of less than 1: 0.1, the reduction efficiency of the secondary antioxidant is lowered, and there is a fear that the antioxidant efficiency due to unreacted peroxide or radical chain reaction may decrease. . In addition, if the primary antioxidant and the secondary antioxidant exceed a weight ratio of 1: 2.0, the removal efficiency of alkyl radicals through the primary antioxidant may decrease, and the secondary antioxidant is mixed with unreacted There is a risk of impairing the uniformity.

In addition, the graphite according to an embodiment of the present invention is a composition for producing a polymer composite, and the additive includes an impact improver, a flame retardant, a strength improver, a heat stabilizer, a light stabilizer, a plasticizer, an antistatic agent, a work improving agent, a UV absorber, a dispersant and a coupling agent. It may be implemented by further including one or more additives selected from the group.

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

The flame retardants include, for example, halogenated flame retardants, like tretabromo bisphenol A oligomers such as BC58 and BC52, brominated polystyrene or poly(dibromo-styrene), brominated epoxy, decabro Modiphenylene oxide, pentabromobenzyl acrylate monomer, pentabromobenzyl acrylate polymer, ethylene-bis(tetrabromophthalimide, bis(pentabromobenzyl)ethane, Mg(OH) ₂ and Al(OH) Metal hydroxides such as 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-tolylsulfonate) Ponyl)-p-toluenesulfimide potassium salt, N-(N'-benzylaminocarbonyl) sulfanylimide potassium salt, or mixtures thereof, but is not limited thereto.The flame retardant is a thermoplastic polymer compound 100 It may be included in an amount of 0.1 to 30 parts by weight based on parts by weight.

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

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

In addition, the light stabilizer may be used without limitation in the case of a known light stabilizer, but as non-limiting examples thereof, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5 benzotriazoles or mixtures thereof, such as -tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxy benzophenone or the like. The light stabilizer may generally be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the total composition excluding all fillers.

In addition, the plasticizer can be used without limitation in the case of known plasticizers, but non-limiting examples thereof include dioctyl-4,5-epoxy-hexahydrophthalate, tris-(octoxycarbonylethyl)isocyanurate, phthalic acid esters 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, a known antistatic agent may be used without limitation, and non-limiting examples thereof include glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzenesulfonate, polyether block. amides, or mixtures thereof, which include, for example, BASF under the trade name 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, as the work improving agent, known work improving agents may be used without limitation, and non-limiting examples thereof include metal stearate, stearyl stearate, pentaerythritol tetrastearate, beeswax, and montan wax. wax), paraffin wax, polyethylene wax or the like, or mixtures thereof. The work improving agent may be included in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the thermoplastic polymer compound.

In addition, the UV absorber functions to prevent and stabilize decomposition by UV, and known UV absorbers can 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 diameter 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, the dispersing agent and the coupling agent may be used without limitation, a known dispersing agent and coupling agent, as a non-limiting example of the coupling agent, maleic acid-grafted polypropylene, a silane-based coupling agent, etc. for heat resistance may be used.

On the other hand, according to an embodiment of the present invention, the above-described graphite-polymer composite manufacturing composition is implemented as a masterbatch for manufacturing a graphite composite material together with a thermoplastic polymer compound. In addition, as shown in FIG. 2, the graphite-polymer composite 1000 is a polymer matrix 200 and a heat dissipation filler 101 according to the present invention dispersed including the inside of the polymer matrix 200 and an antioxidant 102. It is implemented, and a protective coating layer 300 may be further provided on the outer surface of the polymer matrix 200 .

Although the antioxidant 102 is shown in an oval shape, it may vary depending on the weight average molecular weight or polymer form of the antioxidant 102 used, and since it is difficult to accurately measure with a measuring device, the shape is schematically shown. It is not limited.

Although the heat dissipation filler 101 and the antioxidant 102 are illustrated as being dispersed only in the inside of the polymer matrix 200 in FIG. 2 , they may be disposed to be exposed on the outer surface differently from FIG.

The heat dissipation filler 101 may be provided in an amount of 10 to 90% by weight based on the total weight of the graphite-polymer composite 1000 . If the heat dissipation filler 101 is provided in less than 10% by weight, the desired heat dissipation and shielding performance may not be achieved. In addition, if provided in excess of 80% by weight, the mechanical strength of the composite material is significantly reduced, moldability such as injection is deteriorated, and it may be difficult to implement into a complex shape.

The polymer matrix 200 is formed of the above-described thermoplastic polymer compound, and detailed descriptions thereof are the same as those described above, and thus will be omitted.

A protective coating layer 300 may be further provided on the outer surface of the polymer matrix 200 . The protective coating layer 300 prevents the separation of the heat dissipation filler 101 located on the surface of the polymer matrix, prevents scratches caused by physical stimuli applied to the surface, and provides an insulating function depending on the material to provide insulation and heat dissipation At the same time, it can be used for applications such as required electronic devices.

The protective coating layer 300 may be implemented with a known thermosetting polymer compound or a 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 types. 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) ), polyetherimide (PEI), and one compound selected from the group consisting of polyimide, or a mixture or copolymer of two or more types, 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 it according to the purpose.

On the other hand, the protective coating layer 300 may interfere with the radiation of the conducted heat in the air. Accordingly, in order to express more improved heat dissipation, in particular, heat radiation characteristics to the outside air, the protective coating layer 300 may be a heat dissipation coating layer further having a heat dissipation filler. The heat dissipation filler can be used without limitation in the case of a known heat dissipation filler, if insulation is required at the same time, at least one insulating heat dissipation filler selected from the group consisting of aluminum oxide, boron nitride, talc, magnesium oxide, silicon carbide, etc. It is preferable to have

The type, particle size, content, etc. of the heat dissipation filler provided in the protective coating layer 400 may be designed differently depending on the purpose, so the present invention is not particularly limited thereto.

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 can add components within the scope of the same spirit. , changes, deletions, additions, etc. may easily suggest other embodiments, but this will also fall within the scope of the present invention.

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

Claims (14)

a heat dissipation filler having a graphite composite including nanoparticles and a catecholamine layer bonded to the graphite surface;
a matrix-forming component comprising a thermoplastic high molecular compound; and
A phenolic primary antioxidant and a phosphite or thiol secondary antioxidant are included in a weight ratio of 1:0.1 to 2.0, and 1 based on 100 parts by weight of the thermoplastic polymer compound. An additive comprising an antioxidant included in an amount of ~ 30 parts by weight; A graphite containing a graphite-molded composition for producing a polymer composite material-master batch for producing a polymer composite material. delete delete delete The method of 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 graphite-molded composition for producing a polymer composite material - master batch for producing a polymer composite material. delete A heat dissipation filler having a graphite composite comprising nanoparticles and a catecholamine layer bonded to the graphite surface;
An additive comprising an antioxidant comprising a primary antioxidant that is a phenol and a secondary antioxidant that is a phosphate or thiol in a weight ratio of 1: 0.1 to 2.0; and
a polymer matrix molded of a thermoplastic polymer compound, and in which the heat dissipation filler and additives are dispersed; including,
The antioxidant is contained in an amount of 1 to 30 parts by weight based on 100 parts by weight of the thermoplastic polymer compound - a graphite-polymer composite. 8. The method of claim 7,
The heat dissipation filler is graphite-polymer composite material contained in 10 to 90% by weight of the total weight of the graphite-polymer composite material. 8. The method of claim 7,
Graphite-polymer composite material further provided with a protective coating layer on the outer surface of the polymer matrix. delete delete delete delete delete

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