KR101333260B1 - Resin compositon for highly thermal conductive insulating materail and insulating fime - Google Patents

Abstract

The present invention is a thermally conductive ceramic compound containing alumina (Al ₂ O ₃ ); Graphene oxide; And a thermosetting resin; and an insulating film comprising a cured product of the resin composition for insulating material and the cured material of the resin composition for insulating material, thereby providing an insulating material capable of realizing excellent heat conduction characteristics without degrading the breakdown voltage strength. Can be.

Description

RESIN COMPOSITON FOR HIGHLY THERMAL CONDUCTIVE INSULATING MATERAIL AND INSULATING FIME}

The present invention relates to a resin composition and an insulating film for high thermal conductivity insulating materials, and more particularly, to a resin composition capable of providing an insulating material capable of realizing excellent thermal conductivity properties without lowering the withstand voltage strength and obtained by using such a resin composition. It relates to an insulation film.

In recent years, as the electronic devices and electronic components tend to be light and short, the degree of integration of electric devices is increasing, and the amount of heat generated by electric devices that operate with electric energy is also greatly increased. Accordingly, there is an increasing demand for improvement of heat dissipation characteristics for effectively dissipating and dissipating heat generated in an electronic device.

Accordingly, various studies have been conducted to implement a heat dissipation characteristic that effectively dissipates and dissipates heat generated from an electric element, and a withstand voltage strength characteristic that can maintain insulation under a constant voltage.

Recently, researches have been conducted to apply carbon-based materials such as carbon nanotubes (CNT), graphene, or fullerene in various fields, such as transparent conductive films, optical materials, energy storage materials, and heat dissipation / insulating materials. It is actively underway. In particular, graphene has excellent electrical conductivity and thermal conductivity compared to carbon nanotubes and fullerenes, and is capable of producing ultra-thin film materials having a level of 1 nm. Many countries are conducting policy research. However, unlike other fields, the heat dissipation / insulation material requires high withstand voltage strength along with electrical insulation. Carbon-based materials are rarely used for heat dissipation / insulation material due to high electrical conductivity.

In particular, with the recent increase in the use of LED devices such as LED lighting and LED backlight, research on the heat dissipation performance of metal PCBs affecting the output and reliability of the LED devices is being actively conducted. Various studies have been made to improve the breakdown voltage strength in order to prevent a phenomenon in which the material itself is destroyed due to discharge under the circumstances.

The present invention is to provide a resin composition for insulating materials that can provide an insulating material capable of realizing excellent thermal conductivity characteristics without lowering the breakdown voltage strength.

Moreover, this invention is for providing the insulating film obtained using the said resin composition for insulating materials.

The present invention is a thermally conductive ceramic compound containing alumina (Al ₂ O ₃ ); Graphene oxide; And a thermosetting resin; provides a resin composition for insulating materials comprising a.

Moreover, this invention provides the insulating film containing the hardened | cured material of the said resin composition for insulating materials.

Hereinafter, a resin composition for an insulating material and an insulating film according to specific embodiments of the present invention will be described in detail.

According to one embodiment of the invention, a thermally conductive ceramic compound including alumina (Al ₂ O ₃ ); Graphene oxide; And a thermosetting resin; a resin composition for an insulating material may be provided.

MEANS TO SOLVE THE PROBLEM The present inventors progress the study about the heat radiation / insulating material applicable to the field | area, such as an LED element, a display apparatus, or a semiconductor substrate, and when a thermally conductive ceramic compound and graphene oxide are added together to a thermosetting resin, high thermal conductivity is carried out. While testing, it has been confirmed that an insulating material having excellent withstand voltage strength can be provided and completed the invention.

In particular, the present inventors, when using the graphene oxide (graphene oxide) in a resin composition or insulating material for insulating material, can exhibit a high thermal conductivity characteristics of graphene (graphene) while achieving excellent withstand voltage strength In addition, it was confirmed that high compatibility with the thermally conductive ceramic compound can be exhibited in the thermosetting resin.

There is no big limitation on the graphene oxide that can be used in the resin composition for the insulating material, and conventional graphene oxide, for example, graphene oxide having a single layer structure having a thickness of about 0.1 nm to 10.0 nm may be used without particular limitation. It is possible. And, in order to prepare such a graphene oxide, a method of obtaining a sheet-shaped graphene oxide that is adhered to the surface of the tape after adhering and detaching the scotch tape to graphite oxide (graphite oxide), the pulverized graphite acidic solution containing an oxidizing agent The method may be used to obtain graphene oxide by oxidizing after adding to the oxidized solution, or to form a graphene oxide layer by applying power after immersing the graphite and the electrode plate in the electrolyte solution and dropping it. .

However, when using graphene oxide obtained from graphite oxide having a d-spacing of 8.700 kPa or more, the heat dissipation / insulating material prepared from the resin composition for insulating material has higher withstand voltage strength and excellent thermal conductivity. Can have characteristics.

Specifically, graphite oxide having a d-spacing of 8.700 kPa or more may be obtained by adding graphite flakes or powder to an acidic solution containing an oxidizing agent and oxidizing for 3 hours or more. . As such, as the oxidation time is increased during the production of graphite oxide, the d-spacing may be increased, and polar functional groups such as carbonyl groups, hydroxyl groups, or epoxy groups may be added to the graphene oxide. More than this can be introduced. Accordingly, the graphene oxide prepared may have high thermal conductivity and electrical insulation and excellent dispersibility.

The resin composition for the insulating material may include 0.01 to 2% by weight of the graphene oxide, preferably 0.1 to 1.0% by weight. When the content of the graphene oxide is too low, the density of graphene oxide dispersed or interconnected between ceramic powders may be low, and thus the thermal conductivity of the insulating film may be low. When the content of the graphene oxide is too large, thermal conductivity Although the degree is high, the breakdown voltage strength of the film may be lowered and dispersibility may be lowered.

On the other hand, the thermally conductive ceramic compound containing alumina (Al ₂ O ₃ ) is included in the insulating material, it can act to transfer the heat generated from the electrical element to the heat sink quickly. Alumina has excellent thermal conductivity of about 38 W / mK and high electrical insulation among general ceramic materials, as well as good filling property with organic binder and low price.

The resin composition for the insulating material may include 48 to 98% by weight of the thermally conductive ceramic compound, preferably 70 to 95% by weight. When the content of such a thermally conductive ceramic compound is too low, the thermal conductivity and withstand voltage strength of the resin composition for insulating material or the insulating material obtained therefrom may not be sufficiently secured. In addition, when the content of the thermally conductive ceramic compound is too large, the thermal conductivity and withstand voltage strength of the resin composition for the insulating material or the insulating material obtained therefrom may be secured to a certain degree, but the flexibility of the insulating material may be greatly reduced. .

On the other hand, the thermally conductive ceramic compound, in addition to alumina (Al ₂ O ₃ ), optionally boron nitride (BN), aluminum nitride (AlN), silicon carbide (SiC), magnesium oxide (MgO), zinc oxide (ZnO) It may further comprise aluminum hydroxide (Al (OH) ₃ ) or a mixture of two or more thereof.

The thermosetting resin may be cured in the form of a film to serve as a substrate on which the thermally conductive ceramic compound and graphene oxide are dispersed. Specific examples of such thermosetting resins include epoxy resins, polyimide resins, phenoxy resins, acrylic resins, or mixtures of two or more thereof. More specifically, as the epoxy resin, bisphenol A type, bisphenol F type, cresol novolac type, phenol novolak type, biphenyl type, naphthalene type, dicyclopentagene type, or a mixture of two or more thereof may be used. It is preferable to use an epoxy resin having properties such as high heat resistance, high temperature insulation, chemical resistance, high adhesion, electrical insulation, high mechanical strength, and flexibility.

The resin composition for the insulating material is 1 to 50% by weight of the thermosetting resin; Preferably it may comprise 4 to 29% by weight. If the content of the thermosetting resin in the composition is too low, the adhesion and flexibility of the insulating film may be lowered. If the content of the thermosetting resin in the composition is too large, the thermal conductivity or withstand voltage strength may be lowered, and the insulating film may be separated from the copper thin film. When laminating between aluminum plates, bleeding may occur severely.

On the other hand, the resin composition for the insulating material may further include graphene with graphene oxide. As such, when graphene oxide and graphene are used together, while the withstand voltage strength of the insulating material prepared from the resin composition for insulating materials can be maintained at a predetermined level, the thermal conductivity can be greatly increased.

In particular, when the graphene oxide and graphene are mixed and used in a weight ratio of 9: 1 to 6: 4, preferably in a weight ratio of 8: 2 to 6.5: 3.5, insulation having excellent thermal conductivity while sufficiently securing the withstand voltage strength Material may be provided. In addition, when graphene oxide and graphene are mixed, an insulating material capable of maintaining a higher withstand voltage strength than a specification while maintaining higher thermal conductivity than at the time of manufacturing an insulation material using only ceramics such as alumina can be provided at a lower cost. can do.

The graphene usable in the resin composition for the insulating material is not particularly limited. For example, the graphene formed on the scotch tape surface desorbed from graphite, the graphene obtained by SiC crystal pyrolysis, or the graphene oxide described above are reduced. Graphene obtained by the use can be used.

In the resin composition for the insulating material, the sum of the weight of graphene oxide and graphene may be 0.01 to 2% by weight, preferably 0.1 to 1.0% by weight. If the content of graphene oxide and graphene is too low, the thermal conductivity improvement effect may be insignificant. If the content of such graphene oxide and graphene is too large, the thermal conductivity improvement effect is great, but the breakdown voltage strength is lowered, oxidation The dispersibility of graphene and graphene is reduced, the flexibility of the insulating film may be greatly reduced.

On the other hand, the resin composition for the insulating material may be in a solution state, and accordingly, the resin composition may further include an organic solvent for the purpose of dissolving each component or imparting an appropriate level of viscosity for applying the composition. have.

The organic solvent usable in the resin composition is not particularly limited, and for example, N-methylpyrrolidinone (NMP), N, N-dimethylacetamide (N, N-dimethylacetamide; DMAc), Tetrahydrofuran (THF), N, N-dimethylformamide (NMF), dimethylsulfoxide (DMSO), cyclohexane, acetonitrile, methanol, ethanol , Isopropanol and the like can be used, but is not limited thereto.

The organic solvent may be used in an amount of 20 to 800 parts by weight based on 100 parts by weight of the thermally conductive ceramic compound, graphene oxide (or graphene oxide and graphene), and a thermosetting resin. If the amount of the organic solvent is too small, the resin composition in solution may be difficult to have an appropriate viscosity or may not be sufficiently dissolved in the solution of each component. In addition, if the amount of the organic solvent is too large, problems such as an increase in the amount of residual solvent due to too low the viscosity of the resin composition in the solution state or a decrease in the dryness of the insulating film to be produced, resulting in a decrease in heat resistance, lowering the withstand voltage strength, etc. May appear.

Meanwhile, the resin composition for the insulating material may further include additives such as a heat stabilizer, a leveling agent, a crosslinking agent, a crosslinking aid, a pigment, a plasticizer, or an adhesion promoter. The amount of such additive used may be appropriately added or subtracted in consideration of the properties of the final product.

Meanwhile, according to another embodiment of the present invention, an insulating film including the cured product of the above-described resin composition for insulating materials may be provided.

Specifically, the insulating film is a thermosetting resin cured into a film; And a thermally conductive ceramic compound and graphene oxide dispersed in the thermosetting resin.

As described above, the insulating film in which the thermally conductive ceramic compound and the graphene oxide are dispersed in the thermosetting resin may not only have high thermal conductivity but also have high withstand voltage strength that is commercially available. In particular, the graphene oxide (graphene oxide) exhibits a high level of thermal conductivity characteristics of the graphene (graphene), while being able to achieve a high withstand voltage strength that the insulating film can be used for metal PCB when used in an insulating material. In addition, it can exhibit high compatibility with the thermally conductive ceramic compound in the thermosetting resin.

The insulating film may have a thickness of 0.01 to 0.20 mm. If the thickness of the insulating film is too thin, it may be difficult to implement the appropriate thermal conductivity characteristics and withstand voltage strength. In addition, if the thickness of the insulating film is too thick, the heat resistance of the metal PCB is increased, the heat dissipation performance is lowered, bleeding may occur severely when the copper thin film and the aluminum plate is laminated, the weight of the sheet increases the product It is also undesirable in terms of weight reduction.

In addition, the insulating film may further include graphene dispersed in the thermosetting resin. As such, when graphene is further included in the insulating film, the withstand voltage strength can be maintained at a predetermined level, and the thermal conductivity can be greatly increased.

Preferably, in the insulating film, the graphene oxide and graphene may be mixed and dispersed in a weight ratio of 9: 1 to 6: 4, preferably in a weight ratio of 8: 2 to 6.5: 3.5. By using the graphene oxide and graphene in the above weight range, it is possible to provide an insulating material having excellent thermal conductivity while ensuring sufficient withstand voltage strength, and higher thermal conductivity than when preparing an insulating material using only ceramics such as alumina. And an insulating material exhibiting withstand voltage strength can be provided at a lower cost.

Specifically, the insulating film including the thermally conductive ceramic compound, graphene oxide, and graphene dispersed in the thermosetting resin may have a thermal conductivity of 3.8 W / mK or more and a breakdown voltage strength of 3.0 kV or more.

Specific details regarding the thermosetting resin, the thermally conductive ceramic compound, the graphene oxide, and the graphene may be applied in the same manner as described above with respect to the resin composition for the insulating material.

On the other hand, the insulating film, each component of the above-mentioned resin composition for insulating materials-the thermosetting resin, a thermally conductive ceramic compound containing alumina (Al ₂ O ₃ ) and graphene oxide (or a mixture of graphene oxide and graphene) Mixing); And it can be prepared through the step of applying and curing the mixture on a predetermined substrate.

Each component of the resin composition for insulating materials may be prepared and mixed in a dissolved state in an organic solvent. In order to better dissolve each of these components in an organic solvent, a thermally conductive ceramic compound including the thermosetting resin and alumina (Al ₂ O ₃ ) may be added to the organic solvent and then stirred at room temperature. After adding graphene oxide (or a mixture of graphene oxide and graphene) to the organic solvent, ultrasonication may be performed using a sonicator.

After mixing the components of the resin composition for the insulating material, by mixing using a device such as a planetary mixer, a high speed mixer, a Henschel mixer or a super mixer, to form a solution having a more uniform distribution and composition Can be.

The prepared mixture can be made to have a viscosity suitable for application by adding the above-mentioned organic solvent.

In addition, the prepared mixture may include some small bubbles, etc., may be removed using a vacuum stirrer, a paste mixer, and the like.

Meanwhile, the prepared mixture may be applied to a solid substrate such as a metal substrate, a metal substrate, a polymer substrate or a glass substrate. The coating or coating method or apparatus conventionally used may be used for the application of the mixture without any limitation, but the knife coating method, the bar coating method, the gravure coating method or the spray method, or the dipping method may be used. Can be used. However, it is preferable to use a knife coating method, a gravure coating method, or a bar coating method in terms of uniform application and coating.

When the applied mixture is cured by applying heat, the above-described insulating film may be formed. This drying step may be performed for 10 minutes to 1 hour at a temperature of 100 ℃ or more, wherein the heat source of heating is not limited.

According to the present invention, there can be provided a resin composition capable of providing an insulating material capable of realizing excellent thermal conductivity characteristics without deterioration of the breakdown voltage strength, and an insulating material obtained using such a resin composition.

1 is a schematic view of a LED heat dissipation package diagram and an insulating film of one embodiment of the invention.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

< Manufacturing example : Oxidation Grapina  Manufacturing>

Production Example 1

(1) Preparation of Graphite Oxide

Flakes in the form of natural graphite powder (flake) in a mixed solution of H ₂ SO ₄ and KMnO ₄ and stirred at 35 ℃ for 3 hours, the vessel is cooled to a temperature below 15 ℃ Deionized water was slowly added. After the pure water was added, the mixture was stirred at room temperature for 2 hours, and then slowly charged with 34.5% H ₂ O ₂ to prepare graphite oxide.

(2) Preparation of Graphene Oxide

The flake graphite oxide powder prepared in the above was put in a 10% diluted HCl solution and stirred for 2 hours. In this process, the graphite oxide powder composed of several layers was divided into two or three layers. Graphene oxide powder could be prepared. The graphene oxide powder thus obtained was put into pure water (Deionized water) of pH 7 and stirred, and then the resultant was washed and put into an oven at about 80 ° C. to obtain graphene oxide powder.

< Example  And Comparative Example : Manufacture of Resin Composition for Insulation Material and Insulation Film>

Example  One

Obtained by adding a solution containing alumina (A-42-2 / Showa Denko) and graphene oxide obtained above to N-methylpyrrolidinone and dispersing for 1 hour using a sonicator (400W) The solution was mixed at room temperature for 30 minutes using a planetary mixer (solution 1).

Epoxy resin (Bisphenol-A type epoxy, YD-011 / Kukdo Chemical) and other ingredients (Rubber modified type epoxy, KR-104 / Kukdo Chemical) are added to N-methylpyrrolidinone, and a mechanical stirrer is used. The mixture was mixed at 60 ° C. for 3 hours (solution 2).

The solution 1 and the solution 2 were mixed for 5 hours using a planetary mixer at room temperature. At this time, the mixture prepared was 90 wt% of alumina, 9.5 wt% of epoxy resin and other components; And 0.5 wt% of graphene oxide.

Thereafter, the obtained mixture was dispersed using a 3-roll mill, and N-methylpyrrolidinone and methanol were added to adjust the viscosity of the mixture to 5,000 cps.

Then, small bubbles were removed from the viscosity-adjusted mixture using a paste mixer. This mixture was applied to a PET (Polyethylene Terephtalate) substrate using a bar coater at a thickness of 100 μm, and the coating was dried at 130 ° C. for 30 minutes to obtain an insulating film.

Example  2

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of a 9: 1 (weight ratio) mixture of graphene oxide and graphene was used instead of 0.5 wt% of graphene oxide.

Example  3

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of an 8: 2 (weight ratio) mixture of graphene oxide and graphene was used instead of 0.5 wt% of graphene oxide.

Example  4

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of a 7: 3 (weight ratio) mixture of graphene oxide and graphene was used instead of 0.5 wt% of graphene oxide.

Example  5

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of graphene oxide and a 6: 4 (weight ratio) mixture of graphene was used instead of 0.5 wt% of graphene oxide.

Comparative Example 1

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of alumina (90.5 wt% of alumina in total) was used instead of 0.5 wt% of graphene oxide.

Comparative Example 2

An insulating film was prepared in the same manner as in Example 1, except that 0.5 wt% of graphene was used instead of 0.5 wt% of graphene oxide.

< Experimental Example : Measurement of Property of Insulation Film>

1. Thermal conductivity measurement

The thermal conductivity of the insulating films obtained in the above Examples and Comparative Examples was evaluated as the thermal conductivity in the vertical direction using a laser flash method corresponding to ASTM E 1461. At this time, the thermal conductivity in the vertical direction was measured by using the LFA 447 NanoFlash (LFA 447 NanoFlash) equipment using a Netzsch Xenon flash (Xenon flash).

2. Withstand voltage strength

The breakdown voltage strength of the insulating films obtained in the above Examples and Comparative Examples was measured using a Zentech 902 apparatus by the method of ASTM D 149. Specifically, the insulating film obtained in the above Examples and Comparative Examples is placed between the cylindrical copper electrode having a diameter of 2.5 cm and a height of 1.5 cm, and the maximum breakdown voltage at a cut-off current of 0.5 mA is obtained. Measured.

The measured thermal conductivity and breakdown voltage strength are shown in Table 1 below.

Thermal conductivity and breakdown voltage measurement results Thermal conductivity (W / mK) Withstand voltage strength (kV) Example 1 3.5 3.22 Example 2 3.7 3.15 Example 3 3.8 3.10 Example 4 4.5 3.01 Example 5 5.3 2.35 Comparative Example 1 2.9 3.66 Comparative Example 2 7.3 0.29

As shown in Table 1, in the embodiment, an insulating film having not only high thermal conductivity but also greatly improved withstand voltage strength was provided. Specifically, the insulating film prepared in Example exhibited thermal conductivity of 3.5 W / mK or higher and withstand voltage strength of 2.0 kV or more. In particular, Examples 3 and 4 exhibited thermal conductivity of 3.8 W / mK or higher and 3.0 kV or higher. Indicated.

On the contrary, Comparative Example 1 using only alumina without using graphene oxide was able to secure the withstand voltage strength to a certain level or more, but it was confirmed that the thermal conductivity was significantly lowered to less than 3.0 W / mK.

In Comparative Example 2 using graphene, high thermal conductivity was shown, but it was confirmed that the dielectric strength was 0.29 kV, which is a level difficult to use as an insulating material.

That is, according to the embodiment, it is possible to provide an insulating material having excellent thermal conductivity while sufficiently securing the withstand voltage strength, and to provide an insulating material having higher thermal conductivity and withstand voltage strength as compared with the case of manufacturing the insulating material using only ceramics such as alumina. It was found that it can be provided at a lower cost.

Claims (13)

Thermally conductive ceramic compounds including alumina (Al ₂ O ₃ );
Graphene oxide; And
Thermosetting resin; The resin composition for insulating materials containing.
The method of claim 1,
The graphene oxide is a resin composition for insulating materials, obtained from graphite oxide having a d-spacing of 8.700 kPa or more.
The method of claim 1,
A resin composition for insulating materials, further comprising graphene.
The method of claim 3,
The resin composition for insulating materials whose weight ratio of graphene oxide and graphene is 9: 1-6: 4.
The method of claim 1,
The thermosetting resin is a resin composition for insulating materials comprising at least one member selected from the group consisting of epoxy resins, polyimide resins, phenoxy resins and acrylic resins.
The method of claim 1,
The thermally conductive ceramic compound is selected from the group consisting of boron nitride (BN), aluminum nitride (AlN), silicon carbide (SiC), magnesium oxide (MgO), zinc oxide (ZnO) and aluminum hydroxide (Al (OH) ₃ ). The resin composition for insulating materials further containing 1 or more types of compounds.
The method of claim 1,
48 to 98% by weight of a thermally conductive ceramic compound including the alumina (Al ₂ O ₃ );
0.01 to 2 wt% of the graphene oxide; And
The resin composition for insulating materials containing 1-50 weight% of said thermosetting resins.
The method of claim 1,
The resin composition for insulating materials which further contains an organic solvent.
The insulating film containing the hardened | cured material of the resin composition for insulating materials of any one of Claims 1-8.
10. The method of claim 9,
Thermosetting resin cured onto film; And
And a thermally conductive ceramic compound and graphene oxide dispersed in the thermosetting resin.
10. The method of claim 9,
Insulating film having a thickness of 0.01 to 0.2 mm.
10. The method of claim 9,
Further comprising graphene dispersed in the thermosetting resin,
An insulating film having a weight ratio of graphene oxide and graphene 9: 1 to 6: 4.
The method of claim 12,
An insulating film having a thermal conductivity of at least 3.8 W / mK and a breakdown voltage strength of at least 3.0 kV.

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