KR20160132196A - High heat dissipative polymer composites and method of the same - Google Patents

Abstract

Provided are: high heat dissipation polymer composite material; and a producing method thereof. The high heat dissipation polymer composite material comprises: one graphite structure including a plurality of expanded graphite particles; and at least one selected from the group consisting of low viscosity monomers, oligomers, resins, and combinations thereof impregnated in the graphite structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a high heat dissipating polymer composite material and a method of manufacturing the same. BACKGROUND ART [0002]

Heat-dissipating polymer composite material and a method of manufacturing the same.

As the electronic devices have become high-performance and miniaturized, and in particular, their thicknesses have become thinner, the electronic devices within the various electronic devices have become larger in capacity and higher in integration, and accordingly, the heat dissipation performance of these electronic products is recognized as a key factor in the performance of the products have.

For example, small electronic devices such as smart phones and tablet PCs emit more heat, so it is important to effectively dissipate heat from these devices. In the automotive field, too, the use of high current components in hybrid cars and fuel cell vehicles It is important to release the generated heat.

When the heat generated during the operation of such electronic devices continues to be accumulated locally, the internal temperature of the device continuously rises, causing a malfunction of the device or a shortening of its service life. In general, It has been reported that when the temperature rises to about 10 ° C, the lifetime of the device is reduced to about half.

Thus, there is a growing demand for the development of a polymer composite material that realizes weight reduction, has excellent molding processability, and has high thermal conductivity and is excellent in heat radiation performance. However, the thermal conductivity of general polymer is very low as 0.15 ~ 0.5 W / mK, so it is difficult to meet the required level of heat dissipation property. Therefore, in order to further improve the heat dissipation property, ceramic, metal filler having high thermal conductivity of 100 W / mK or more, Graphite and the like, but their thermal conductivity is not sufficiently improved due to their low dispersibility in the polymer, and when the conductive filler is added in an excessive amount, it is difficult to process the polymer.

In one embodiment of the present invention, a highly heat-dissipating polymer composite material is provided that uniformly implements excellent heat dissipation properties in an isotropic manner to further prevent malfunction and shortened life span of an electronic product.

In another embodiment of the present invention, a method for producing the high heat dissipating polymer composite material is provided.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

The high heat dissipating polymer composite material includes a single graphite structure impregnated with the monomer having a low viscosity described above rather than being contained in a state where the expanded graphite particles are mixed and stirred in the polymer and separated from each other.

As described above, the high heat dissipating polymer composite material includes a single graphite structure as a single structure having a predetermined three-dimensional network structure in which a plurality of expanded graphite particles are in contact with each other, The graphite particles are not separated from each other but are connected to each other in total so that the thermal conductivity is higher in all directions and therefore the excellent heat radiation performance can be uniformed in all directions without any problem of anisotropy of the thermal conductivity and local temperature rise There is an advantage to be implemented.

As a result, it is possible to effectively prevent accumulation of local heat by rapidly discharging heat generated in the product using the high heat dissipating polymer composite material in all directions, thereby preventing damage to the product, have.

The plurality of expanded graphite particles are expanded together in a limited space in the mold so that a plurality of expanded graphite particles are present in connection with each other so that the graphite structure is formed by a predetermined three- Network structure, and thus a high thermal conductivity can be realized in all directions.

The high heat dissipating polymer composite material can uniformly realize excellent heat dissipation in all directions, thereby further preventing the malfunction and the life span of the electronic product.

1 is a schematic cross-sectional view of a high heat dissipating polymer composite according to an embodiment of the present invention.
FIG. 2 is an image photograph obtained by enlarging a predetermined three-dimensionally connected network structure of one graphite structure before impregnation of a monomer or the like with a scanning electron microscope (JEOL, JSM-6700).
FIG. 3 is an image photograph of the high heat dissipating polymer composite according to Comparative Example 4 taken by scanning electron microscope (JEOL, JSM-6700).
4 is a schematic process flow diagram of a method of manufacturing a high heat dissipating polymer composite material according to another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

1 is a schematic cross-sectional view of a high heat dissipating polymer composite material 100 according to an embodiment of the present invention.

In one embodiment of the invention, one graphite structure (110) comprising a plurality of expanded graphite particles; And at least one (120) selected from the group consisting of low-viscosity monomers, oligomers, resins, and combinations thereof impregnated into the graphite structure (110) is cured or polymerized to form a high heat dissipating polymer composite The material 100 is provided. Specifically, the preliminary composite material is subjected to heat treatment or light irradiation to form a high heat dissipation polymer composite material (hereinafter referred to as " high heat dissipation polymer composite material ") formed by curing or polymerizing at least one member selected from the group consisting of the monomer, the oligomer, (100). In Fig. 1, reference numeral 110 denotes a graphite structure formed as a single structure in which a plurality of expanded graphite particles are in contact with each other so as not to refer to the expanded graphite particles themselves.

Herein, the preliminary composite material means an intermediate material for forming the high heat dissipation polymer composite material 100, and it is preferable that the high heat dissipation polymer composite material 100 is formed from the preliminary composite material by heat treatment or light irradiation can do.

In general, a polymer has a low thermal conductivity and thus has a disadvantage that the heat radiation performance is not sufficient. In addition, when a large amount of conductive filler is added to improve the heat radiation performance, workability and formability, which are merits of polymers, are lost, and when a small amount of nanofiller such as carbon nanotubes is added to improve moldability, The dispersibility is not ensured due to the cohesiveness of the resin, and the thermal conductivity is low and non-uniform, and they are agglomerated with each other, so that the mechanical strength is rapidly deteriorated. In particular, it has had to have a very limited thermal conductivity due to pores contained in the composite material, or phonon scattering occurring at the interface of the filler and the matrix.

Specifically, one-dimensional nanomaterials such as carbon nanotubes and metal nanowires; Two-dimensional nanomaterials such as graphene and graphene nanoplates; The filler of the filler is orientated in a direction of the polymer in the course of processing. Particularly, an injection-molded composite material having a high flow rate of a molten resin and the like has a specific orientation of the filler depending on the flow direction of the resin when the filler is injected into the mold. The thermal conductivity of the composite material also has anisotropy, so that there are many restrictions on the design of the parts.

In addition, expanded graphite and the like tend to aggregate in the polymer, and it is very difficult to uniformly disperse the graphite. Accordingly, the heat-radiating sheet, the heat-radiating adhesive tape, and the like manufactured using the polymer composition formed by simply mixing and stirring the expanded graphite in the molten polymer exhibit non-uniform thermal conductivity and mechanical properties depending on the position, The discharge may not be smoothly performed, and the temperature may locally rise, thereby causing malfunction and shortening of life of the electronic product.

Accordingly, in one embodiment of the present invention, the high heat dissipating polymer composite material 100 is not contained in a state where a plurality of expanded graphite particles are mixed and agitated in the polymer and are spaced apart from each other, but the low- And one graphite structure 110 impregnated with the graphite structure 120.

In the present specification, one graphite structure 110 means a single structure having a predetermined three-dimensional network structure in which a plurality of expanded graphite particles contained therein are in contact with each other, and the high heat dissipating polymer composite material 100 Since the plurality of expanded graphite particles in the high heat dissipating polymer composite material 100 are not separated but are entirely tangent to each other by including the one graphite structure 110, the thermal conductivity is higher in all directions, There is an advantage that an excellent heat radiation performance can be realized at a uniform level in all directions without the problem of the anisotropy of the thermal conductivity and the problem of the local temperature rise.

As a result, the heat generated in the product using the high heat dissipating polymer composite material 100 is rapidly discharged in all directions, thereby effectively preventing the accumulation of local heat, thereby preventing damage to the product, Can be extended.

1, a space between a plurality of expanded graphite particles forming one graphite structure 110, that is, a gap between the expanded graphite particles 110 and the voids in the one graphite structure 110, 1, but voids between the expanded graphite particles directly contacting with each other are impregnated with a monomer 120 or the like having a low viscosity although not shown in Fig.

The one graphite structure 110 can be formed, for example, by expanding a plurality of expansible graphite particles in a mold, thereby forming a single structure having a predetermined shape corresponding to the shape of the mold . The mold is a kind of mold that is used to form the graphite structure 110 and includes all of a flask, a mold, an injection mold, and the like.

That is, the plurality of expansive graphite particles are expanded together in a limited space in the mold, so that a plurality of expanded graphite particles are connected to each other, so that the graphite structure 110 contacts the expanded graphite particles Can be formed in the following predetermined three-dimensional network structure, thereby realizing a high thermal conductivity in all directions. FIG. 2 is a view illustrating a three-dimensionally connected network structure of one graphite structure 110 before impregnation of a low-viscosity monomer or the like 120 with a scanning electron microscope (JEOL, JSM-6700) It is an image photograph.

The shape, density, expansion rate, etc. of the graphite structure 110 can be appropriately adjusted by selecting the shape, volume, etc. of the mold according to the purpose and use of the invention, and is not particularly limited.

The expandable graphite particles may be referred to as a graphite intercalation compound (GIC), and the graphite intercalation compound may be expanded by heat treatment at a temperature of, for example, about 200 ° C. to about 500 ° C., ), But is not limited thereto.

The graphite structure 110 may be impregnated with at least one monomer selected from the group consisting of low viscosity monomers, oligomers, resins, and combinations thereof, so that the graphite structure 110 may be impregnated with a predetermined three- It is possible to realize excellent molding processability while firmly maintaining the network structure.

The impregnation of the monomer, oligomer, resin or the like 120 may be performed according to a known impregnation method in the art, for example, by immersing the graphite structure 110 in the resin or the like, 110 by spraying or injecting the resin or the like.

The high heat dissipating polymer composite material 100 further includes a coating formed on the surface of the graphite structure 110 and containing at least one of the monomers, the oligomer, the resin, and combinations thereof can do.

The monomer, the oligomer, and the resin may comprise a thermoplastic compound, a thermosetting compound, or both.

For example, the thermoplastic compound may be selected from the group consisting of a diene compound, a vinyl compound, a vinyl aromatic compound, an alcohol compound, an amine compound, a sulfide compound, a thermoplastic acrylic compound, an amide compound, And the like. For example, the thermoplastic compound may be selected from the group consisting of polyethylene, polyprooylene, polyurethane, polyethyleneterephthalate, polybutyleneterephthalate, polyurea, poly Polyvinylchloride, polyvinylacetate, ethylenevinylacetate, polyphenylene sulfide, polyamide, polyimide, polybenzimidazole, poly (vinylidene chloride), poly Polyetheretherketone, and the like, but are not limited thereto.

The thermosetting compound may include at least one selected from the group consisting of, for example, an epoxy compound, an amino compound, a phenol compound, an unsaturated polyester compound, a thermosetting acrylic compound, a silicone compound, But is not limited thereto.

In one embodiment, the monomer, the oligomer, and the resin may be a thermoplastic compound or a thermosetting compound having a low viscosity, so that the monomer, the oligomer, and the resin can be easily infiltrated into the void space in the graphite structure 110, And the porosity of the high heat dissipating polymer composite material 100 can be lowered.

As described above, since the porosity of the high heat dissipating polymer composite material 100 is reduced to a low level, deterioration of heat transfer performance due to air having low thermal conductivity can be effectively prevented, and more excellent heat radiation performance can be realized.

At least one (120) selected from the group consisting of the monomers, oligomers, resins and combinations thereof may have a viscosity of less than about 5,000 cP, for example, at a temperature of about 25 ° C, 3,000 cP, and more specifically from about 0.5 cP to about 2,000 cP.

By having a low viscosity within the above range, it is possible to more easily penetrate and impregnate into the void space in the graphite structure 110, thereby realizing a lower level of porosity in the high heat dissipating polymer composite material 100.

In one embodiment, the content of graphite structure 110 may be from about 2% to about 60% by weight. The total amount of the monomer, the oligomer, and the resin may be, for example, from about 39% by weight to about 98% by weight, and specifically from about 39% by weight to about 97% by weight.

When the content of the graphite structure 110 is within the above range, the graphite structure 110 is sufficiently present in the high heat dissipating polymer composite material 100 as a whole, so that the heat dissipation performance can be achieved isotropically. Impregnated and impregnated. Specifically, when the content of the graphite structure 110 is less than about 2% by weight, it is difficult for a predetermined three-dimensional network structure in which graphite particles expanded in the high heat dissipating polymer composite material 100 to contact each other, And the graphite structure 110 is too compact, it is difficult for the above-mentioned monomers and the like to penetrate.

Also, the preliminary composite material may be selected from the group consisting of carbon nanotubes, metal nanowires, low melting point alloys, metal nanoparticles, graphene, graphene nanoplates, and combinations thereof embedded or embedded in the graphite structure 110 And at least one thermally conductive filler.

As described above, the high heat dissipating polymer composite material 100 further includes the thermally conductive filler, thereby effectively improving the isotropic heat transfer performance and realizing a better heat dissipation performance.

The content of the thermally conductive filler may be 0.1 wt% to 20 wt%. By being included in the content within the above range, excellent heat radiation performance and excellent mechanical properties can be realized.

Further, the preliminary composite material may further include, for example, a photoinitiator, a thermal initiator, a photo-curing agent, a thermosetting agent, and the like, and they may be suitably used in the art and are not particularly limited.

In one embodiment, the graphite structure 110 can be pretreated according to the purpose and use of the invention, and the pretreatment can be carried out in the group comprising, for example, dispersants, coupling agents, surfactants and combinations thereof And other additives including at least one selected, but are not limited thereto.

Further, as described above, the high heat dissipating polymer composite material 100 can be formed by curing or polymerizing the preliminary composite material, and more specifically, by mixing the monomer, the oligomer, the resin, At least one member selected from the group consisting of a combination of two or more members may be formed by curing or polymerizing. That is, the high heat dissipating polymer composite material 100 may include a cured product or a polymeric material formed by curing or polymerizing at least one (120) selected from the group consisting of the monomer, the oligomer, the resin, have.

At least one (120) selected from the group consisting of the monomer, the oligomer, the resin and combinations thereof may be partially or fully cured or polymerized according to the object and use of the invention, and the monomer or the like 120 may be partially , The high heat dissipating polymer composite material 100 may have adhesiveness or adhesiveness and may have a rigid property when it is completely cured or polymerized.

The thermal conductivity of the high heat dissipating polymer composite material 100 may be, for example, from about 1 W / mK to about 100 W / mK. By having a thermal conductivity within the above range, it is possible to realize more excellent heat radiation performance.

Also, the high heat dissipating polymer composite material 100 may have a density of about 0.4 g / cm ³ to about 1.60 g / cm ³ . By having the density within the above range, the porosity in the high heat dissipating polymer composite material 100 can be realized at a low level, and the heat transfer performance can be further improved.

Specifically, if the density of the high heat dissipating polymer composite material 100 is less than about 0.4 g / cm ³ , penetration of the resin or the like occurs only partially, and the mechanical properties are remarkably low. If the density is more than about 1.60 g / cm ³ , There is a problem that the monomer or the like can not penetrate because the structure is too compact, that is, the structure is dense.

The high heat dissipating polymer composite material 100 may be, for example, a high heat dissipating polymer composite material 100 for an electronic product. Specifically, the high heat dissipating polymer composite material 100 may be applied to a heat dissipation housing, a heat dissipation adhesive tape, and a heat dissipation adhesive sheet. For example, the thickness of the mold can be made thinner and the thickness of the high heat dissipating polymer composite material 100 can be thinned, so that it can be easily applied to small electronic parts. Accordingly, it is possible to effectively solve the local heating problem of an electronic device, for example, a mobile communication terminal or an LED display device.

For example, when applied to the use of heat-resisting adhesive tape or heat-radiating adhesive sheet, the adhesive strength of the high heat dissipating polymer composite material 100 may be about 100 _gf / 25 mm or more.

In another embodiment of the present invention, there is provided a method for forming a graphite structure, comprising: expanding a plurality of expandable graphite particles in a mold to form one graphite structure having a predetermined shape corresponding to the shape of the mold; Impregnating the graphite structure with at least one selected from the group consisting of monomers, oligomers, resins, and combinations thereof to form a preliminary composite material; And a step of curing or polymerizing the preliminary composite material to produce a high heat dissipating polymer composite material therefrom. In one embodiment, the above-described high heat dissipating polymer composite material can be produced by the above production method. Accordingly, the graphite structure, the monomer, the oligomer, and the resin are as described above in one embodiment.

In the above production method, it is possible to expand a plurality of expansive graphite particles in a mold to form one graphite structure having a predetermined shape corresponding to the shape of the mold.

The plurality of expandable graphite particles may be expanded by heat treatment and heat treatment may be performed, for example, at a temperature of about 200 캜 to about 500 캜, but is not limited thereto.

The graphite structure can be formed, for example, by expanding a plurality of intumescent graphite particles in a mold, thereby forming a single structure having a predetermined shape corresponding to the shape of the mold. The mold is a kind of mold that is used to form the graphite structure, and includes all of a flask, a mold, an injection mold, and the like.

That is, the plurality of expandable graphite particles are expanded together in a limited space in the mold, so that a plurality of expanded graphite particles are connected to each other, whereby the graphite structure is formed so that the plurality of expanded graphite particles contact each other It can be formed in a three-dimensional network structure, thereby achieving isotropic heat dissipation.

The shape, density, expansion rate, etc. of the graphite structure can be appropriately adjusted by selecting the shape, volume, etc. of the mold according to the purpose and use of the invention, and is not particularly limited.

In addition, in the above production method, the graphite structure may be impregnated with at least one selected from the group consisting of low viscosity monomers, oligomers, resins, and combinations thereof to form a preliminary composite material.

The monomer, the oligomer, and the resin may include a thermoplastic compound having a low viscosity, a thermosetting compound, or both of them. Accordingly, the monomer, the oligomer, and the resin can be easily impregnated into the void space in the graphite structure, , The porosity of the high heat dissipating polymer composite material can be lowered.

As described above, since the porosity of the high heat dissipating polymer composite material is reduced to a low level, deterioration of heat transfer performance due to air having low thermal conductivity can be effectively prevented, and more excellent heat radiation performance can be realized.

At least one selected from the group consisting of the monomer, the oligomer, the resin and combinations thereof may be formed to have a viscosity of less than about 5,000 cP, for example, at a temperature of about 25 캜, 3,000 cP, and more specifically from about 0.5 cP to about 2,000 cP.

By forming the material with a low viscosity within the above range, it is possible to more easily penetrate and impregnate into the void space in the graphite structure, thereby realizing a lower level of porosity in the high heat dissipating polymer composite material.

The impregnation of the monomer, the oligomer, the resin or the like can be carried out according to an impregnation method known in the art, for example, by immersing the graphite structure in the resin or spraying the resin or the like into the graphite structure Can be performed by injection.

In the above production method, the preliminary composite material may be formed such that the content of the graphite structure is about 2 wt% to about 60 wt%. The total amount of the monomer, the oligomer, and the resin may be, for example, about 39 wt% to about 98 wt%, and specifically about 39 wt% to about 97 wt%. .

By forming the preliminary composite material so as to have the content within the above range, the graphite structure as a whole is sufficiently present in the high heat dissipating polymer composite material, so that the heat dissipation performance can be achieved isotropically, and the resin or the like easily penetrates into the graphite structure, . Specifically, when the content of the graphite structure is less than about 2% by weight, it is difficult for the graphite particles expanded in the high heat-dissipating polymer composite material to contact each other to form a predetermined three-dimensional network structure, %, The graphite structure is too compact, and the above-mentioned monomers and the like are difficult to permeate.

In addition, in the above production method, the preliminary composite material may be cured or polymerized to prepare a high heat dissipation polymer composite material.

The curing may be thermal curing or photo curing, and the polymerization may be thermal curing or photopolymerizing, for example, the thermal curing and the thermal curing may be performed by heat treatment at a temperature of about-20 C to about 350 C , And the photopolymerization and the photopolymerization can be performed by, for example, a metal halide lamp or the like, but the present invention is not limited thereto, by irradiating UV of about 100 mJ / cm ² to about 5000 mJ / cm ² .

In the above manufacturing method, it is preferable that, before the expansion of the plurality of expandable graphite particles, the mold is selected from the group consisting of carbon nanotubes, metal nanowires, low melting point alloys, metal nanoparticles, graphene, And further adding a thermally conductive filler containing at least one of the thermally conductive fillers.

Accordingly, by expanding the plurality of expandable graphite particles in the mold in a state where the plurality of expandable graphite particles and the thermally conductive filler are mixed, the thermally conductive filler in the preliminary composite material or the high- It is not agglomerated and can be trapped or inserted into the graphite structure as a whole at a uniform level.

As described above, the high heat dissipating polymer composite material further including the thermally conductive filler effectively improves the isotropic heat transfer performance, thereby realizing better heat radiation performance.

The content of the thermally conductive filler may be 0.1 wt% to 20 wt%. By being included in the content within the above range, excellent heat radiation performance and excellent mechanical properties can be realized.

Further, in the above manufacturing method, it may further include performing a pre-treatment on the graphite structure. The pretreatment may be performed by, for example, but not exclusively, treating with a vapor comprising at least one selected from the group consisting of dispersants, coupling agents, surfactants, and combinations thereof.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and the present invention should not be limited thereto.

Example

Example  One

A mold having a diameter of 50 mm and a thickness of 10 mm was prepared and 2g of the graphite intercalation compound was heat-treated at 300 ° C in the mold to expand the graphite structure to form one graphite structure.

Subsequently, 18 g of a composition obtained by mixing an epoxy resin (EP-3000-32, Pace Technologies, USA) and a curing agent (EH-3000-08, Pace Technologies, USA) at a ratio of 5: 1 was impregnated into the graphite structure, A preliminary composite material was formed.

Then, the preliminary composite material was heat-treated at 80 ° C for 1 hour to prepare a high heat dissipating polymer composite material.

The content of the graphite structure in the preliminary composite material was 10% by weight, and the content of the resin was 90% by weight.

Example  2

A high heat dissipating polymer composite material was prepared in the same manner as in Example 1, except that the content of the graphite structure in the preliminary composite material was 2% by weight and the content of the resin was 98% by weight.

Example  3

A high heat dissipating polymer composite material was prepared in the same manner as in Example 1 except that the content of the graphite structure in the preliminary composite material was 30% by weight and the content of the resin was 70% by weight.

Example  4

A mold having a diameter of 50 mm and a thickness of 10 mm was prepared and 2g of the graphite intercalation compound was heat-treated at 300 ° C in the mold to expand the graphite structure to form one graphite structure.

Next, 18 g of a composition obtained by mixing a styrene monomer (Sigma Aldrich Co., USA) and benzoyl peroxide was impregnated into the graphite structure to form a preliminary composite material.

Next, the preliminary composite material was thermally cured at 80 DEG C for 1 hour to prepare a high heat dissipating polymer composite material.

The content of the graphite structure in the preliminary composite material was 10% by weight, and the content of the monomer was 90% by weight.

Example  5

A mold having a diameter of 50 mm and a thickness of 10 mm was prepared and 2g of the graphite intercalation compound was heat-treated at 300 ° C in the mold to expand the graphite structure to form one graphite structure.

Subsequently, 18 g of an acrylic monomer composition (viscosity of 2 centipoise, viscosity of 20 mPa.s) mixed with 75 wt% of 2-ethylhexyl acrylate, 10 wt% of acrylic acid, 3 wt% of methyl methacrylate, 12 wt% of methyl acrylate and 0.1 wt% cP) was impregnated into the graphite structure to form a preliminary composite material.

Then, the preliminary composite material was thermally cured at 60 DEG C for 1 hour and 30 minutes to prepare a high heat dissipating polymer composite material.

The content of the graphite structure in the preliminary composite material was 10% by weight, and the total content of the monomers was 90% by weight.

Comparative Example 1 (when a plurality of expanded graphite particles do not form one graphite structure and are mixed and stirred in the molten polymer)

The graphite intercalate compound was heated in a muffle furnace at 450 DEG C and allowed to stand for 10 minutes to expand to form a plurality of expanded graphite particles.

2 g of the expanded graphite particles were mixed at a ratio of 5: 1 with an epoxy resin (EP-3000-32, Pace Technologies, USA) and a curing agent (EH-3000-08, Pace Technologies, USA) Was added to 18 g of the composition and stirred to prepare a polymer composition.

The polymer composition was thermally cured at 80 DEG C for 1 hour to prepare a polymer composite.

The total content of the plurality of expanded graphite particles mixed and contained in the polymer composition was 10% by weight, and the content of the resin was 90% by weight.

Comparative Example 2 (when a plurality of expanded graphite particles do not form one graphite structure but are mixed and stirred in the molten polymer)

A polymer composite material was prepared in the same manner as in Comparative Example 1 except that the total content of the expanded graphite particles was 2% by weight and the content of the resin was 98% by weight .

Comparative Example 3 (when a plurality of expanded graphite particles do not form one graphite structure and are mixed and stirred in a molten polymer)

A polymer composite material was prepared in the same manner as in Comparative Example 1 except that the total content of the expanded graphite particles was 30% by weight and the content of the resin was 70% by weight .

Comparative Example 4 (when a plurality of expanded graphite particles do not form a single graphite structure but are mixed and stirred in a molten polymer)

The graphite intercalate compound was heated in a muffle furnace at 450 DEG C and allowed to stand for 10 minutes to expand to form a plurality of expanded graphite particles.

2 g of the expanded graphite particles were mixed with 75 wt% of 2-ethylhexyl acrylate, 10 wt% of acrylic acid, 3 wt% of methyl methacrylate, 12 wt% of methyl acrylate, and 0.1 wt% of benzoyl peroxide The resulting mixture was added to a total of 18 g of acrylic syrup (viscosity 8200 cP) formed by polymerizing the mixed composition and stirred to prepare a polymer composition.

The polymer composition was thermally cured at 80 DEG C for 1 hour to prepare a polymer composite.

The total amount of the expanded graphite particles mixed and contained in the polymer composition was 10% by weight, and the content of the acrylic syrup was 90% by weight.

FIG. 3 is an image photograph of the high heat dissipating polymer composite material according to Comparative Example 4 taken with a scanning electron microscope (JEOL, JSM-6700).

Comparative Example 5 (when a plurality of expanded graphite particles do not form one graphite structure and are mixed and stirred in a molten polymer)

According to the same conditions and in the same manner as in Comparative Example 4, except that the total amount of the expanded graphite particles mixed and contained in the polymer composition was 4% by weight and the content of the acrylic syrup was 96% by weight, To prepare a composite material.

Comparative Example 6 (Nylon 6,6 melt blending)

The graphite intercalate compound was heated in a muffle furnace at 450 DEG C and allowed to stand for 10 minutes to expand to form a plurality of expanded graphite particles.

18 g of the expanded graphite particles were mixed in a Nylon 6,6 resin (Radipol A 45, Radici Chimica, Italy) and then placed in a Brabenda ^® batch mixer and melt mixed at 280 rpm at 60 rpm for 10 minutes to prepare a polymer composition And cooled to obtain a polymer composite material.

The total content of the plurality of expanded graphite particles mixed and contained in the polymer composition was 10% by weight, and the content of the resin was 90% by weight.

Experimental Example

The physical properties of the high heat dissipating polymer composite material according to Example 1-5 and Comparative Example 1-6 were evaluated and are shown in Table 1 below.

Assessment Methods

(Thermal conductivity)

Measuring method: The thermal conductivity was measured using a thermal conductivity measuring device (Anter, Model: Quickline) according to the Guarded Heat flow method.

 (Density of composite material)

Measuring method: The high heat dissipating polymer composite material obtained in Examples 1-4 and Comparative Examples 1-5 was broken and prepared as a specimen of 1 to 3 g, and an electronic densimeter (Alfa Mirage, Japan, MD -300S) was used to measure the density of each specimen.

(Viscosity)

Measurement methods: The viscosities of the respective resins, monomers, syrup, etc. used in Examples 1-4 and Comparative Examples 1-5 were measured using a viscometer (Brookfield, model: LVDV II).

division Whether or not a single graphite structure is formed by being swollen together in the mold Content of Graphite Structure (wt%) density
(g / cm ³⁾ Viscosity (cP) Thermal conductivity
(W / mK) Example 1 ○ 10 1.17 1100 4.81 Example 2 ○ 4 1.14 1100 3.01 Example 3 ○ 30 1.31 1100 21.1 Example 4 ○ 10 1.05 1.1 5.62 Example 5 ○ 10 1.20 1.2 5.28 Comparative Example 1 X 10 0.88 1100 0.45 Comparative Example 2 X 4 0.97 1100 0.26 Comparative Example 3 X 30 No agitation 1100 No agitation Comparative Example 4 X 10 0.98 8200 0.34 Comparative Example 5 X 4 0.94 8200 0.23 Comparative Example 6 X 10 1.11 50,000 0.36

As shown in Table 1, it was clearly confirmed that the high heat dissipating polymer composite according to Example 1-5 realizes excellent thermal conductivity, that is, a predetermined three-dimensional network in which a plurality of expanded graphite particles contact each other, Since the plurality of expanded graphite particles in the high heat dissipating polymer composite material are entirely in contact with each other by the one graphite structure which is a single structure having a structure, the thermal conductivity is higher in all directions, It can be clearly expected that an excellent heat radiation performance can be realized at uniform levels in all directions without the problem of anisotropy and local temperature rise.

On the other hand, the polymer composite according to Comparative Example 1-6 clearly confirmed that the thermal conductivity was all less than 0.5 W / mK and the thermal conductivity was remarkably low, that is, the plurality of expanded graphite particles were not connected to each other in the polymer composite material , It can be clearly predicted that the thermal conductivity is low since it is spaced apart.

100: Polymer composites
110: one graphite structure
120: low-viscosity monomer, oligomer, resin

Claims (5)

A graphite structure comprising a plurality of expanded graphite particles; And at least one selected from the group consisting of monomers, oligomers, resins, and combinations thereof having a low viscosity impregnated in the graphite structure, which is formed by thermosetting or photo-curing
High heat dissipation polymer composite.
The method according to claim 1,
At least one selected from the group consisting of the monomer, the oligomer, the resin and combinations thereof has a viscosity of less than 5,000 cp
High heat dissipation polymer composite.
The method according to claim 1,
The content of the graphite structure is about 2 wt% to about 60 wt%
High heat dissipation polymer composite.
The method according to claim 1,
A thermally conductive filler containing at least one selected from the group consisting of carbon nanotubes, metal nanowires, low melting point alloys, metal nanoparticles, graphene, graphene nanoplates, and combinations thereof embedded or embedded in the graphite structure Included
High heat dissipation polymer composite.
Expanding a plurality of expandable graphite particles in a mold to form one graphite structure having a predetermined shape corresponding to the shape of the mold;
Impregnating the graphite structure with at least one selected from the group consisting of low viscosity monomers, oligomers, resins, and combinations thereof to form a preliminary composite material; And
Thermally curing or photo-curing the pre-composite material to produce a heat-dissipating polymer composite material therefrom;
Wherein the heat-resistant polymer composite material is a thermosetting resin.

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