KR20190074498A - Resin with high themal conductivity - Google Patents

Abstract

The present invention provides a high heat dissipation composite resin comprising 35 to 55 wt% of a thermoplastic resin, 12 to 14 wt% of a carbon fiber, 35 to 45 wt% of graphite and 1 to 3 wt% of a graphene nanoplate functionalized with an amino group. The high heat dissipation composite resin is excellent in thermal conductivity and mechanical strength.

Description

[0001] RESIN WITH HIGH THEMAL CONDUCTIVITY [0002]

TECHNICAL FIELD The present invention relates to a high heat dissipation composite resin composition, and relates to a high heat dissipation composite resin having excellent thermal conductivity and mechanical strength.

Currently, the importance of heat management for improving the efficiency of electronic parts and preventing malfunctions is emphasized in all industrial fields, and the market for heat dissipation material capable of releasing heat generated from electronic parts through heat dissipation is rapidly growing. Until now, the most widely used materials for heat dissipation materials are metals, metals have higher thermal conductivity than other materials, and they have excellent heat dissipation properties and are used as heat dissipation materials in various fields.

Recently, alternative heat-dissipating materials that can replace metals with high specific gravity are required due to automobile lightweighting issues. Polymer materials have advantages such as low density, design freedom and chemical resistance compared with metal. Based on this, it is possible to produce a variety of thermally conductive polymer composite material which is produced by dispersing metal or non-metal filler having excellent thermal conductivity in polymer resin Research is underway. However, the thermally conductive polymer composites developed so far have limited thermal conductivity and mechanical properties to replace metals. On the other hand, in general, as the content of the thermally conductive filler in the polymer resin increases, the thermal conductivity of the polymer composite resin increases, and in order to achieve a high level of thermal conductivity, a high content of the thermally conductive filler must be added. However, when a high-content thermally conductive filler is added to the polymer resin, the specific gravity is increased, the mechanical properties are rapidly deteriorated, and the molding of the product is not properly performed at the time of injection molding. Therefore, studies have been made on the development of heat dissipation materials having excellent mechanical properties compared to the conventional thermally conductive polymer composite materials, which are excellent in thermal conductivity against low specific gravity in order to replace metals as heat dissipation materials.

One example of such a technique is disclosed in Patent Document 1 below.

That is, the following Patent Document 1 relates to a resin composition having excellent heat dissipation characteristics, electromagnetic shielding and absorbing ability, and a molded article produced using the resin composition, which comprises 5 to 30% by weight of a semi-graphene, 10 to 35% by weight of the polymeric material and 20 to 60% by weight of the polymeric material.

However, the above-described Patent Document 1 has a low specific gravity compared to metal, but has a relatively low thermal conductivity of 6.1 W / Mk, which makes it difficult to apply to products requiring high thermal conductivity.

Korean Patent No. 10-1579522

It is an object of the present invention to provide a high heat dissipation composite resin composition excellent in thermal conductivity and mechanical strength.

The object of the invention is not limited to the objects mentioned above. The objects of the present invention will become more apparent from the following description, which will be realized by means of the appended claims and their combinations.

35 to 55 wt% of thermoplastic resin, 35 to 45 wt% of graphite, 12 to 14 wt% of carbon fiber, and 1 to 3 wt% of graphene nanoflakes functionalized with an amino group according to an embodiment of the present invention.

In one embodiment of the present invention, the thermoplastic resin is selected from the group consisting of polyamide, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polycarbonate, polyphenylene oxide, polyphenylene sulfite, and combinations thereof .

In one embodiment of the present invention, the weight average molecular weight of the polyamide may be 10,000 to 200,000 g / mol.

In one embodiment of the present invention, the carbon fiber comprises a core and a coating layer formed on at least one region of the core surface, wherein the core is selected from the group consisting of pitch, rayon, polyacrylonitrile, and combinations thereof And the coating layer may be selected from the group consisting of an epoxy resin, a polyurethane resin, a polyamide resin, and a combination thereof.

In one embodiment of the present invention, the length of the carbon fiber may be 5 to 7 mm.

In one embodiment of the present invention, the average particle size of the graphite may be 18 to 24 탆.

In one embodiment of the present invention, the high heat dissipation composite resin further includes an additive, and the additive may be 0.4 to 1.2 wt% based on the total weight%.

In one embodiment of the present invention, the additive is selected from the group consisting of antioxidants, lubricants, and combinations thereof, wherein the antioxidant is present in an amount of 0.3 to 0.7 wt.%, Based on the total weight percent, By weight, based on the total weight of the composition.

In one embodiment of the present invention, the high heat dissipation composite resin has a density of 1.6 g / cm 2 or less, a tensile strength of 1200 kgf / cm 2 or more, a thermal conductivity of 15 W / mK or more, and a melt index of 5 g / have.

According to an embodiment of the present invention, a highly heat-dissipating composite resin having excellent thermal conductivity and mechanical strength can be provided by mixing and dispersing a thermoplastic resin, graphite, carbon fiber, and graphene nanoplate functionalized with an amino group.

Fig. 1 is a table showing results of measurement of thermal diffusivity of Example 1 and PA6 of the present invention. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown enlarged from the actual for the sake of clarity of the present invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, where a portion such as a layer, film, region, plate, or the like is referred to as being "on" another portion, this includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part such as a layer, film, region, plate or the like is referred to as being "under" another part, it includes not only the case where it is "directly underneath" another part but also another part in the middle.

Unless otherwise specified, all numbers, values, and / or representations that express the amounts of components, reaction conditions, polymer compositions, and combinations used herein are intended to include those numbers It should be understood that in all cases the term "about" is to be construed as an approximation reflecting the various uncertainties of the measurement. Also, where a numerical range is disclosed in this specification, such a range is contiguous and includes all values from the minimum value of this range to the maximum value including the maximum value, unless otherwise indicated. Further, when such a range refers to an integer, all integers including the minimum value to the maximum value including the maximum value are included unless otherwise indicated.

In the present specification, when a range is described for a variable, it will be understood that the variable includes all values within the stated range including the end points described in the range. For example, a range of "5 to 10" may include any subrange, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., as well as values of 5, 6, 7, 8, 9, And will also be understood to include any value between integers that are reasonable within the scope of the stated ranges such as 5.5, 6.5, 7.5, 5.5 to 8.5 and 6.5 to 9, and so on. Also, for example, a range of "10% to 30%" may range from 10% to 15%, 12% to 12%, as well as all integers including values of 10%, 11%, 12%, 13% And any arbitrary integer within the range of ranges described, such as 10.5%, 15.5%, 25.5%, and the like, including any subranges such as 18%, 20%

Hereinafter, the high heat dissipation composite resin composition of the present invention will be described in detail.

The high heat dissipation composite resin composition of the present invention includes a thermoplastic resin, graphite, a carbon fiber, and a graphene nanoplate functionalized with an amino group. Specifically, it is a mixture of 35 to 55% by weight of thermoplastic resin, 35 to 45% by weight of graphite, 12 to 14% by weight of carbon fiber and 1 to 3% by weight of graphene nanoplate functionalized with an amino group.

First, the components of the high heat-dissipating composite resin composition and reasons for limitation of each component will be described.

The thermoplastic resin may be selected from the group consisting of polyamide, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polycarbonate, polyphenylene oxide, polyphenylene sulfide, and combinations thereof, .

The polyamide includes an amide group in a main chain of the polymer and is mainly composed of an amino acid, a lactam, a diamine, a dicarboxylic acid and a combination thereof, and is polymerized to prepare a copolymer can do. Specifically, for example, the polyamide may be selected from the group consisting of polycaprolactam (PA6), poly (11-aminoundecanoic acid), PA11, polylaurylactam (PA12), polyhexa Polyhexamethylene adipamide (PA66), polyhexaethylene azelamide (PA69), polyhexaethylene sebacamide (PA610), polyhexaethylene dodecanodiamide (PA612), and polyhexamethylene adipamide And combinations thereof. Specifically, the polyamide may be a copolymer of polycaprolactam or polyamide, for example, a copolymer of PA6 and PA610, a copolymer of PA6 and PA66, a copolymer of PA6 and PA12.

In this case, the weight average molecular weight of the polyamide may be 10,000 to 200,000 g / mol, preferably 30,000 to 100,000 g / mol, because the flowability and mechanical properties are excellent in the above-mentioned range.

The thermoplastic resin is a component that affects rigidity, toughness, abrasion resistance, chemical resistance, oil resistance and moldability, and may include 35 to 55% by weight, preferably 35.2 to 53.2% by weight based on the total weight%. If the amount is less than 35% by weight, the amount of the thermoplastic resin composition to be used is too small and the moldability and mechanical properties of the thermoplastic resin composition may deteriorate. If the amount exceeds 55% by weight, .

Graphite is one of the most known materials as a heat-radiating material because of its high thermal conductivity, and may be at least one selected from natural graphite and artificial graphite. At this time, the graphite may have a carbon content of 99% or more, and the average particle size of the graphite particles may be 18 to 24 탆. If the average particle diameter of the graphite is less than 18 탆, the compatibility with the thermoplastic resin may deteriorate due to the agglomeration phenomenon between the graphite particles. If the average particle diameter exceeds 24 탆, the mechanical properties may deteriorate.

The graphite may be 35 to 45% by weight based on the total weight%. If the content is less than 35% by weight, the effect of improving the thermal conductivity due to the addition of graphite is insignificant. If the content exceeds 45% by weight, the dispersibility of the filler in the composite resin may be deteriorated and the mechanical strength and workability of the product may be deteriorated.

The carbon fiber is a component used for improving mechanical properties, and may have a carbon content of 90 wt% or more, and may be chopped carbon fiber.

The carbon fiber may include a core and a coating layer formed on at least one region of the core surface. The core may be selected from the group consisting of pitch, rayon, polyacrylonitrile, and combinations thereof, and the coating layer may be selected from the group consisting of an epoxy resin, a polyurethane resin, a polyamide resin, and combinations thereof. If the coating layer is not composed of the above-described composition, the adhesion between the carbon fibers and the thermoplastic resin is deteriorated, so that the carbon fibers are not uniformly dispersed and the physical properties of the composite resin may be deteriorated. Details will be described later.

The average length of the carbon fibers may be 5 to 7 mm. If it is less than 5 mm, the mechanical properties may be largely deteriorated, and if it exceeds 7 mm, the dispersion may be difficult and the product formability may be deteriorated.

The carbon fiber may be 12 to 14% by weight based on the total weight%. If it is less than 12% by weight, the thermal conductivity is lowered and can be lower than 15 W / mk. If it exceeds 14% by weight, the moldability is lowered and it may be difficult to have a complicated heat radiation structure. Therefore, it is preferable that the carbon fiber is contained in an amount of 12 to 14% by weight so that the mechanical properties and the product formability can be excellent at the same time.

Graphene Nano Plate (GNP) is a two-dimensional single-sheet sheet composed of carbon sp2 hybrid. It has a shape similar to graphene and has excellent thermal properties. Do. However, the graphene nanoplate has a very stable chemical structure due to the action of van der walls force between the graphene nanoplate, which easily causes agglomeration. Therefore, it is difficult to bond with other materials, Dispersion may be difficult. Such nonuniform dispersion not only lowers the mechanical strength of the polymer composite material but also lowers the flowability, which may adversely affect the product molding.

The present invention is characterized by using an NH 2 Functionalized Graphene Nano Plate functionalized with an amino group. The graphene nanoparticle functionalized with the amino group may be one in which the amino group is chemically bonded to the carbon skeleton of the graphene nanoplate. The amino group ratio may be 24 to 26% by weight.

As described above, in the present invention, by using an amino group-functionalized graphene nano plate (NH2-GNP, NH2 Functionalized Graphene Nano Plate), the graphene nanoplate in the composite resin can be improved in mechanical properties, thermal conductivity and formability have.

The NH 2 -GNP (NH 2 Functionalized Graphene Nano Plate) functionalized with an amino group may be 1 to 3% by weight based on the total weight%. If it is less than 1% by weight, the effect of improving the thermal conductivity of the composite resin is insignificant. If it exceeds 3% by weight, the mechanical strength and workability of the product may be difficult due to the lowering of the dispersibility of the filler in the composite resin.

In the present invention, when the amino group of the graphene nanoplate functionalized with an amino group and the amide group (hydrogen bond) between the amide group of the thermoplastic resin and the coating layer of the carbon fiber are epoxy, the bond between -O- and the amide group of the thermoplastic resin (Hydrogen bond), a bond between a hydroxyl group and an amide group of a thermoplastic resin when the coating layer of the carbon fiber is polyurethane, and a coating layer of carbon fiber with a polyamide, wherein the bonding between the amide group and the amide group of the thermoplastic resin functions as an amino group The fin nano plate, the thermoplastic resin, the carbon fiber and the thermoplastic resin can be strongly bonded, and the graphene nanoplate and the carbon fiber in the composite resin can be uniformly dispersed. Therefore, an effect of improving mechanical properties, thermal conductivity and moldability can be induced.

The high heat dissipation composite resin of the present invention may further contain additives in addition to the above-mentioned components. Since such an additive is included in an extremely small amount, the present invention can be appropriately adjusted depending on various factors such as desired end use and characteristics, and the content thereof is not limited.

The additive may be selected from the group consisting of an antioxidant, a lubricant, a compatibilizer, a colorant, a release agent, a flame retardant, a plasticizer, and a combination thereof, and may preferably be selected from the group consisting of an antioxidant, a lubricant and a combination thereof. The additive may be 0.4 to 1.2% by weight, preferably 0.6 to 1.0% by weight, based on the total weight%. If it is less than 0.4% by weight, oxidation resistance and moldability may be deteriorated. If it exceeds 1.2% by weight, heat conduction and mechanical properties may be deteriorated. Specifically, the antioxidant is added in order to prevent aging of the polymer due to high temperature during the injection process and extrusion process and to secure long-term heat resistance. The antioxidant is added in an amount of 0.3 to 0.7 wt%, preferably 0.4 to 0.6 wt% And the lubricant is added to increase the miscibility of the resin, and it may be 0.1 to 0.5 wt%, preferably 0.2 to 0.4 wt%, based on the total weight%.

Examples 1-4. Manufacture of composite resin

The weight percentages of each component disclosed in the following Table 1 were applied as follows.

Polycaprolactam (1027BRT, manufactured by Hyosung Corporation), antioxidant (IRGANOX1010 from CIBA Chemical Co.), lubricant (Hi-Lube) were added to the primary feed inlet of a twin-screw extruder (L / D = 44, (SC-20OQKG, GK (purity: 99% or more, average particle size: 18-24um) and NH2-GNP (AD) were introduced into a secondary inlet located in the middle of the twin- (Thickness: 2-5 nm, surface area: ~ 250 m < 2 > / g) manufactured by Nano Technologies Inc.), and a carbon fiber (TR06Q, Mitsubishi Rayon Co., epoxy, chopped carbon fiber with a length of 6 mm) was injected into the reactor, followed by a hot melt kneading step to produce a composite resin.

Table 1 is a table showing the components of each of the composite resins of Examples 1 to 4 in terms of% by weight.

division Example 1 Example 2 Example 3 Example 4 Polycaprolactam 45.20 43.20 48.20 40.20 Carbon fiber 13.00 13.00 13.00 13.00 black smoke 40.00 40.00 35.00 45.00 NH2-GNP 1.00 3.00 3.00 1.00 Antioxidant 0.50 0.50 0.50 0.50 slush 0.30 0.30 0.30 0.30

Comparative Examples 1 to 12. Manufacture of composite resin

The composite resins of Comparative Examples 1 to 12 were prepared in the same manner as in the production methods of Examples 1 to 4 except that the weight% of each component shown in Table 2 below was used.

Table 2 shows the components of the composite resins of Comparative Examples 1 to 12 in weight percent.

division Polycaprolactam Carbon fiber black smoke NH2-GNP Antioxidant slush Comparative Example 1 48.20 10.00 40.00 1.00 0.50 0.30 Comparative Example 2 42.20 16.00 40.00 1.00 0.50 0.30 Comparative Example 3 51.20 10.00 35.00 3.00 0.50 0.30 Comparative Example 4 45.20 16.00 35.00 3.00 0.50 0.30 Comparative Example 5 50.20 13.00 35.00 1.00 0.50 0.30 Comparative Example 6 46.20 13.00 35.00 5.00 0.50 0.30 Comparative Example 7 46.20 13.00 40.00 0.00 0.50 0.30 Comparative Example 8 41.20 13.00 40.00 5.00 0.50 0.30 Comparative Example 9 53.20 13.00 30.00 3.00 0.50 0.30 Comparative Example 10 38.20 13.00 45.00 3.00 0.50 0.30 Comparative Example 11 35.20 13.00 50.00 1.00 0.50 0.30 Comparative Example 12 41.20 13.00 45.00 0.00 0.50 0.30

Experimental Example 1. Characteristics of Composite Material

In order to evaluate the mechanical properties of the composite materials produced in Examples 1 to 4 and Comparative Examples 1 to 12 according to the present invention, the following experiment was conducted.

The composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 12 were dried in a hot-air dryer at a temperature of 90 ° C for 4 hours and then injected at a temperature of 285 ° C to produce pellets. The pellets were pressed at a pressure of 150t Specimens were prepared.

The specimens were allowed to stand for 48 hours under the conditions of a temperature of 23 ° C and a relative humidity of 50%, and then the density, tensile strength, thermal conductivity, melt index and moldability were measured under the conditions shown in Table 3 below.

Table 3 is a table showing the apparatus and conditions for measuring the mechanical properties of the composite material.

division Device Condition Density (g / cm2) ASTM D792 - Tensile strength (kgf / cm2) ASTM D638 5mm / min Specific heat (J / (g K) ASTM E1952 - Thermal Diffusivity Coefficient (㎟ / s) ASTM E1461 In-plane direction The melt index (g / 10 min) ASTM D1238 275 ° C / 10 kg Formability Evaluate whether the injection product is unformed. Thermal conductivity (W / Mk) Thermal conductivity (k) = thermal diffusivity (a) x specific heat (Cp) x density (p)

Table 4 shows the results of measurement of density, tensile strength, thermal conductivity, melt index and moldability.

As a result, in Examples 1 to 4, all conditions such as a density of 1.6 g / cm 2 or less, a tensile strength of 1200 kgf / cm 2 or more, a melt index of 5 g / 10 min or more, a thermal conductivity of 15 W / mK or more, , It was confirmed that the physical properties of Examples 1 to 4 were generally excellent. Thus, Examples 1 to 4 of the present invention were found to have excellent injection moldability, thermal conductivity and mechanical properties as compared with Comparative Examples 1 to 12.

division density The tensile strength Thermal conductivity Melt Index Formability Example 1 1.512 1284.0 15.60 9.8 Good Example 2 1.530 1214.0 17.70 5.8 Good Example 3 1.494 1267.0 15.20 7.6 Good Example 4 1.562 1205.0 18.20 7.8 Good Comparative Example 1 1.499 1189.0 15.60 11.6 Good Comparative Example 2 1.530 1392.0 15.70 4.6 Bad Comparative Example 3 1.470 1173.0 15.20 9.9 Good Comparative Example 4 1.522 1325.0 15.40 4.5 Bad Comparative Example 5 1.469 1348.0 12.70 11.9 Good Comparative Example 6 1.505 1182.0 17.60 3.8 Bad Comparative Example 7 1.503 1311.0 13.20 11.9 Good Comparative Example 8 1.542 1121.0 20.10 1.9 Bad Comparative Example 9 1.449 1322.0 13.10 9.2 Good Comparative Example 10 1.578 1131.0 21.50 3.2 Bad Comparative Example 11 1.615 1118.0 20.40 4.8 Bad Comparative Example 12 1.554 1241.0 14.60 8.8 Good

Experimental Example 2: Thermal properties of a composite material

In order to confirm the thermal characteristics of the present invention, experiments were conducted as follows using the specimen and the polycaprolactam (hereinafter referred to as 'PA6') of Example 1 prepared in Experimental Example 1.

Fig. 1 is a table showing results of measurement of thermal diffusivity of Example 1 and PA6 of the present invention. Fig.

As a result, referring to FIG. 1, in Example 1, it was confirmed that the temperature deviation was 15.6 and the temperature deviation was smaller than PA6. Therefore, it can be seen that the first embodiment of the present invention has good heat transfer in the direction away from the heat source, and thus has excellent horizontal heat spreading.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

Claims (9)

35 to 55% by weight of a thermoplastic resin;
35 to 45% by weight of graphite;
12 to 14% by weight of carbon fiber; And
1 to 3% by weight of a graphene nanoplate functionalized with an amino group.
The method according to claim 1,
Wherein the thermoplastic resin is selected from the group consisting of polyamide, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polycarbonate, polyphenylene oxide, polyphenylene sulfite, and combinations thereof.
3. The method of claim 2,
Wherein the polyamide has a weight average molecular weight of 10000 to 200000 g / mol.
The method according to claim 1,
Wherein the carbon fiber comprises a core; And
And a coating layer formed on at least one region of the core surface,
Wherein the core is selected from the group consisting of pitch, rayon, polyacrylonitrile, and combinations thereof,
Wherein the coating layer is selected from the group consisting of an epoxy resin, a polyurethane resin, a polyamide resin, and a combination thereof.
The method according to claim 1,
Wherein the carbon fiber has a length of 5 to 7 mm.
The method according to claim 1,
Wherein said graphite has an average particle diameter of 18 to 24 um.
The method according to claim 1,
Wherein the high heat dissipation composite resin further comprises an additive,
Wherein the additive is 0.4 to 1.2% by weight based on the total weight%.
8. The method of claim 7,
Wherein the additive is selected from the group consisting of antioxidants, lubricants, and combinations thereof,
The antioxidant is contained in an amount of 0.3 to 0.7% by weight based on the total weight%
Wherein the lubricant is 0.1 to 0.5% by weight based on the total weight%.
The method according to claim 1,
Wherein the high heat dissipation composite resin has a density of 1.6 g / cm 2 or less, a tensile strength of 1200 kgf / cm 2 or more, a thermal conductivity of 15 W / mK or more, and a melt index of 5 g / 10 min.

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