KR20110012023A - Coating composition for heat-dissipation including carbon black - Google Patents

Abstract

PURPOSE: A coating composition for heat dissipation is provided to reduce a process through low temperature heat treatment of only a solvent component present in a binder even though a high temperature sintering process is not passed. CONSTITUTION: A coating composition for heat dissipation comprises 100.0 parts by weight of carbon black and 20-200 parts by weight of binder. The binder is a cellulose-based material. The coating composition for heat dissipation further includes carbon nanotubes. The carbon nanotubes are included in the amount of 2-8 parts by weight based on 100.0 parts by weight of carbon black.

Description

Coating composition for heat-dissipation including carbon black

FIELD OF THE INVENTION The present invention relates to heat release coating compositions, and more particularly to heat release coating compositions comprising carbon black.

Due to the high performance and miniaturization of electronic components and equipment, as more devices are integrated in a limited space, heat generation of electronic components per unit area is rapidly increasing. In addition, one of the important tasks to be solved by the optical device component industry, such as LED, which is in the spotlight recently, is heat dissipation.

In particular, as the efficiency of electronic components such as LEDs is increased, the heat dissipation amount of the LED package is increased to a considerable level, and there is a need for countermeasures for heat dissipation. Therefore, miniaturization of electronic components and application of new applications are impossible without solving the heat dissipation problem.

Furthermore, in the case of semiconductor devices and optical devices such as LEDs, when the heat generated cannot be effectively released, the luminous efficiency is lowered due to deterioration of the chip itself or the packaging resin, resulting in shortening of the chip life.

Heat dissipation of electronic components proceeds in the form of heat conduction, heat radiation, and heat convection. The heat convection method of releasing heat by causing convection with a small fan in the heat dissipation form has problems such as noise, power consumption, volume increase, and unit price increase.

On the other hand, the method of dissipating heat by heat conduction is not only as good as the heat dissipation effect is expected, but also the production cost is increased and the weight is increased because it uses a metal with good thermal conductivity such as gold, silver, or copper. There was an increasing problem.

In addition, heat dissipation using the existing aluminum or copper heat sinks requires a wide heat sink, so an increase in the overall volume of the product is inevitable and its efficiency is not as high as expected.

Therefore, studies are being actively conducted to increase the heat radiation efficiency of the heat sink, and one of them is an attempt to increase the radiation efficiency by coating the heat sink with a material having good heat radiation efficiency.

Since heat radiation emits absorbed heat in the form of electromagnetic waves, it is considered that there are many advantages in releasing heat using heat radiation in a limited space such as an electronic component.

Such thermal radiation requires materials with high thermal conductivity.

One such material, carbon black, is a solid particulate material that is industrially produced by incomplete combustion of a hydrocarbon gas or an oal.

In general, carbon black is classified into channel black, furnace black, thermal black, acetylene black, etc. according to the manufacturing method. The furnace black performs a process continuously. It can be used, and can be mass-produced, and is used most often, and channel black is used for high-quality grafting pigments.

Since the carbon black is a fine powder having a large surface area and its own cohesive force is larger than that of other materials, it is not easily dispersed in a medium. Thus, in order to manufacture a product having a uniform property using carbon black, the carbon black may be used to increase affinity with a medium. Technology development is greatly required.

Particle size, structure, and surface chemical properties can be mentioned as factors affecting the dispersibility of the carbon black, of which surface chemical properties are very important for understanding the interaction with the medium. Carbon black is composed of 90% or more carbon, 3-8% oxygen, and less than 1% hydrogen atom and other impurities, and in the surface or pores of carbon black, carboxyl group, phenolic hydroxyl group, lactone group, carbonyl group Functional groups such as

Although functional groups present on the surface of the carbon black are small in number, they combine with polymer materials such as rubber and plastics to form a matrix, thereby playing an important role in improving physical properties of the composite material.

In particular, when carbon black is used as a coating composite material, the shape, particle size, binding property, thermal expansion property, thickness of the coating layer, etc. of the reinforcing particles should be considered in order to improve emission amount and material properties.

When using such carbon black for heat dissipation, a binder for applying the carbon black to the target product is required. The binder must be suitable for the properties of the target carbon black so that heat release performance can be optimized.

Meanwhile, patent application 10-2007-0008544 discloses a heat dissipating material for an exothermic electronic device comprising an acrylic polymer, at least one liquid resin, and a blend of thermally conductive particles and at least one solid resin which is an optional component. However, the above application has a disadvantage in that it adopts only boron nitride as thermally conductive particles, and combines the boron nitride with an acrylic polymer, an acrylate, a liquid resin, a surface active agent, and the like, and has an overly complicated configuration.

In order to solve the problems of the prior art as described above, the present invention is excellent in thermal conductivity and thermal emissivity It is intended to provide a heat release coating composition comprising carbon black and a binder.

In addition, the present invention is to provide an electronic material maximized heat dissipation efficiency using the heat dissipation coating composition comprising the carbon black.

The heat dissipation coating composition according to one feature of the present invention for solving the above problems includes a carbon black and a binder.

The carbon black and the binder may be mixed with 20 to 200 parts by weight of a binder based on 100 parts by weight of carbon black.

In the coating composition, the binder is preferably a cellulose-based resin.

The cellulose-based resin may be prepared by selecting one or more from the group consisting of ethyl cellulose, propyl cellulose, isopropyl cellulose, and butyl cellulose.

The coating composition may further include carbon nanotubes.

In the coating composition, the carbon nanotubes may be further added in an amount of 2 to 8 parts by weight based on 100 parts by weight of the carbon black.

In the coating composition, the carbon black preferably has a particle size of 1 to 50㎛.

An electronic device according to another aspect of the present invention includes the coating composition.

In the electronic device, the heat release coating composition may be coated on the electronic device, and then heated at 120 to 200 ° C. to volatilize the solvent of the binder.

The heat dissipation coating composition of the present invention is prepared by using carbon black having excellent heat conduction and heat dissipation ability and a binder which binds them without limiting the heat dissipation ability of the carbon black, thereby not limiting the heat dissipation ability of the carbon black. Therefore, it has excellent heat conduction and heat radiation efficiency.

In addition, the heat dissipation coating composition of the present invention is prepared using carbon black, which is inexpensive and easy to purchase, and thus can be easily coated and used on electronic devices or components without economic burden.

In addition, since the heat dissipation coating composition of the present invention does not use an inorganic binder, only the solvent component present in the binder may be volatilized at a relatively low temperature without volatilization without a high temperature sintering process of 1000 ° C. or higher, thereby shortening the process.

Accordingly, the present inventors have made diligent research efforts to overcome the problems of the prior art, by adopting carbon black as the thermally conductive particles, by developing and applying a binder that does not specifically limit the thermal radiation ability of the carbon black, It was confirmed that the heat dissipation coating composition having excellent heat conduction efficiency can be prepared, and the present invention has been completed.

Accordingly, the heat release coating composition of the present invention comprises carbon black and a binder.

In order to control the particle size of the carbon black, the particle size of the carbon black was adjusted by sieve filtering.

In the present invention, the carbon black is preferably used in a particle size of 1 to 50㎛. In the case of using a carbon black material having a size less than the above range has the disadvantage of poor workability due to the dispersion of fine particles into the air during processing, uniformly with the binder when using a carbon black material having a size exceeding the above range Since the carbon black is not properly bonded through the binder because it is not bonded, even when coated with the heat release coating composition, the desired heat release efficiency may not be achieved, which may adversely affect the electronic device or the electronic component.

In the present invention, the binder imparts bonding properties to the carbon black, and an binder optimized for the bonding of the carbon black is preferably used.

The binder is homogeneously mixed with carbon black and applied to a heat sink of an electronic material requiring heat release. A solvent of the binder is volatilized by a drying process, and only the solute portion is included in the coating composition to thermally radiate together with carbon black. Perform the function. Therefore, a binder must be used in which the solvent is volatilized and the solute in the remaining binder does not impair the heat radiating function of the carbon black. In particular, in the present invention, the coating composition including the carbon black may be coated by performing only a drying process at a relatively low temperature of 120 ° C to 180 ° C. Thus, the solute in the binder may be coated with carbon black without volatilization in the drying process to perform a heat radiation function.

The kind of the binder that can be used in the present invention that satisfies these properties is preferably a cellulose resin. The cellulose-based resin may be prepared by selecting one or more from the group consisting of ethyl cellulose, propyl cellulose, isopropyl cellulose, and butyl cellulose.

In the present invention, the carbon black and the binder are preferably mixed with 20 to 200 parts by weight of the binder based on 100 parts by weight of carbon black.

When the binder is added in less than 20 parts by weight, the carbon black and the binder is not homogeneously mixed, the carbon black is agglomerated and present a problem due to the deterioration of the dispersibility of the carbon black, such as a binder is less than 20 parts by weight The surface of the coating layer treated with the coating composition prepared by adding may not be smooth and may cause disadvantages such as irregularities may occur. In addition, when added in excess of 200 parts by weight, the content of carbon black having good thermal radiation efficiency is lowered, so that the radiation efficiency of the coating composition as a whole is lowered.

In addition, the present invention may further include a carbon nanotube (CNT) in addition to the carbon black and the binder to prepare a heat release coating composition.

In the present invention, when the carbon nanotubes of carbon material such as carbon black are further added, the carbon nanotubes having good thermal conductivity and thermal emissivity are homogeneously mixed with the carbon black and the binder to perform a heat radiating function together with the carbon black. The thermal conductivity of the overall coating layer may be further improved to prepare a coating composition having improved heat radiation efficiency.

The heat dissipation coating composition thus prepared may be coated and used on an electronic material or a component requiring a heat dissipation function.

Hereinafter, the present invention will be described in detail with reference to a preferred embodiment so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Example  One

36 g of carbon black was prepared by sifting the carbon black with a sieve of 26 mu m size.

As a binder, 8 g of ethyl cellulose (CAS NO. 9004-57-3, Junsei Chemical Co. LTD) was used, and 8 g of tepitol (Tepitol, Wako pure chemical industries, Ltd.) as a solvent of the binder, and butyl carbitol 48 g of acetate (BCA, butyl carbitol acetate, Dongyang Chemical Co., Ltd.) was mixed and prepared.

The prepared carbon black and the binder were mixed and stirred at 50 ° C. for 3 hours to prepare a paste-type heat dissipation coating composition. The heat release coating composition thus prepared was coated on an Al substrate (40 × 40 × 3 mm) and then dried at 150 ° C. for 30 minutes.

Example  2

A heat release coating composition was prepared in the same manner as in Example 1, except that 1.8 g of Nanocarbon CNT75 powder was further added.

The heat release coating composition thus prepared was coated on an Al substrate (40x40x3mm) and dried at 150 ° C. for 30 minutes.

Comparative example  1 to 4

To the heat release coating composition was prepared in the same manner as in Example 1 according to the graphite type, sieve size and binder conditions described in Table 1.

Experimental Example  1. Thermal emissivity measurement

Thermal emissivity was measured for the coating compositions prepared in Examples and Comparative Examples.

Thermal emissivity was measured at a temperature of 50 ℃, 100 ℃ using a far-infrared measuring equipment owned by the Institute of Technology (Table 2).

Analyzing the measurement results, the substrates prepared in Examples 1 to 2 coated with the heat release coating composition containing carbon black were coated on the substrates prepared in Comparative Examples 1 to 4 coated with the heat release coating composition containing graphite. Compared to the radiation energy and thermal emissivity items showed higher efficiency.

In addition, the thermal radiation efficiency of the substrate of Example 2 coated with the coating composition prepared by adding the carbon nanotubes was higher than that of Example 1 or the comparative example coated with the coating composition prepared without the addition of the carbon nanotubes. It could be known. This is because the carbon nanotubes having good thermal conductivity and thermal emissivity are homogeneously mixed with the carbon black and the binder to perform the heat radiation function together with the carbon black, thereby increasing the average thermal radiation efficiency.

In particular, the binder is volatilized by the drying process, and only the solute component is coated with the carbon black, and the solute component is used to improve the thermal emissivity between the carbon black components without limiting the heat radiating function of the carbon black. As an aid, it is believed to increase the spinning efficiency of the thermally radiating coating composition of the present invention as a whole.

Referring to these results, it was found that not only the role of carbon black powder or carbon nanotubes, which plays a role of heat radiation, but also the binder and the solute included in the binder play an important role in heat radiation efficiency.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the technical idea of the present invention, which also belong to the appended claims. It is natural.

Claims (8)

A heat release coating composition comprising 100 parts by weight of carbon black and 20 to 200 parts by weight of the binder. The heat release coating composition of claim 1, wherein the binder is cellulose-based. 3. The heat dissipating coating composition according to claim 2, wherein the cellulose series comprises at least one selected from the group consisting of ethyl cellulose, propyl cellulose, isopropyl cellulose, and butyl cellulose. The heat release coating composition according to any one of claims 1 to 3, further comprising a carbon nanotube. The heat dissipating coating composition according to claim 4, wherein the carbon nanotubes are further added in an amount of 2 to 8 parts by weight based on 100 parts by weight of the carbon black. The heat release coating composition according to claim 1, wherein the carbon black has a particle size size of 1 to 50 μm. An electronic device, characterized in that at least part of the surface is coated with the heat release coating composition according to any one of claims 1 to 3. The electronic device of claim 7, wherein the heat dissipation coating composition is coated on the electronic device, and then heated at 120 to 200 ° C. to volatilize the solvent of the binder.