KR101666053B1 - Heat Radiant Paint and nanotubes and Method for forming Heat Radiant coating layer of using the same - Google Patents

Abstract

And a method of forming a heat radiation coating film using the same. The heat radiating paint comprises 1 to 10% by weight of carbon nanotubes to which a functional group is introduced, 5 to 40% by weight of ceramic powder, 30 to 60% by weight of a polyester resin having a hydroxy group, 5 to 10% 0.01 to 0.2% by weight of thermal initiator, and an excess of organic solvent. The heat radiating paint enhances the heat radiation efficiency of the heat radiating material to improve the cooling efficiency and functions as a thermal diffusion layer to uniformly transmit heat.

Description

TECHNICAL FIELD [0001] The present invention relates to a heat radiating paint and a method of forming a heat radiating coating film using the heat radiating paint.

The present invention relates to a heat radiation paint and a method of forming a heat radiation coating film using the same. More particularly, the present invention relates to a heat dissipation coating material applied to a heat dissipation device for electric and electronic parts and a method for forming a heat dissipation coating film using the same.

The importance of low-power design, heat-dissipation and high-heat-resistance materials is getting bigger in accordance with the trend of high-tech devices to be slim and light, and heat problems of electronic devices and internal combustion engines are becoming big issues both at home and abroad.

Typical organic / inorganic materials are characterized by thermal conductivity, which starts to generate heat as the power or heat source is supplied. At this time, it is necessary to disperse the heat transferred as much as possible so as not to be concentrated in one place, and to discharge it out as quickly as possible. In order to discharge heat, a physical method or a material change method is generally used.

 In this case, there is a problem that the lifetime of the device is shortened due to the heat generation of the LED, so that the device must be frequently replaced or repaired. In the case of lighting appliances, backlight units (BLUs) for display LCDs, etc., other types of home appliances also require heat dissipation performance in order to improve the efficiency and stability of the products. In order to improve the heat dissipation performance, a technique for a heat radiation paint (Korean Application No. 2010-0138637) was proposed. However, in the case of the above-mentioned heat-radiating coating, the dispersibility of the binder resin and the conductive filler is low, and cracking of the coating film occurs during processing.

An object of the present invention is to provide a high radiant heat-radiating coating which is easy to apply the application of heat-radiating parts of metal and has excellent workability without peeling and cracking of the coating film at the time of shape processing.

Another object of the present invention is to provide a heat-radiating coating film which can efficiently radiate heat from the surface of the heat sink. ,

According to an aspect of the present invention, there is provided a heat dissipation coating material comprising 1 to 10% by weight of carbon nanotubes having a functional group introduced thereinto, 5 to 40% by weight of a ceramic powder, 30 to 60% by weight of an ester resin, 5 to 10% by weight of a curing resin, 0.01 to 0.2% by weight of a heat initiator and an excess of an organic solvent.

In one embodiment, a carbon nanotube having a functional group introduced on the surface thereof is prepared by reacting a carboxyl group on the surface of the carbon nanotube modified by an acid treatment with a monomer containing an oxirane group, Carbon double bond group.

In one embodiment, the ceramic powder may be aluminum oxide, magnesium oxide, tin oxide, hydrocarbons, boron nitride, silicon nitride, etc., or may be used alone or in combination.

In one embodiment, the polyester resin having a hydroxy group is a polyester resin having a glass transition temperature in the range of 10 to 40 占 폚, a number average molecular weight of 7,000 to 15,000 and a hydroxyl value of 10 to 40 desirable.

In one embodiment, the curable resin may be selected from a melamine resin and a block isocyanate resin.

In order to accomplish the above object, the heat radiation coating layer according to an embodiment of the present invention may be formed by coating a heat radiation coating material on a target object, followed by thermally curing the heat radiation coating material coated on the object surface. The heat dissipation coating material may include 1 to 10% by weight of carbon nanotubes having a functional group introduced on the surface thereof; 5 to 30% by weight of a ceramic powder; 30 to 60% by weight of a polyester resin having a hydroxy group; 5 to 10% by weight of a curing resin; 0.01 to 0.2% by weight of thermal initiator and an excess of organic solvent.

In one embodiment, the heat radiation coating film can be formed by applying any one coating method selected from spray coating, roll coating, dipping coating, comma coating, gravure coating and electrodeposition coating. To form a heat dissipation coating film.

The heat dissipation coating composition according to the present invention uses a nanotube and a ceramic powder into which a functional group is introduced to form a uniform dispersion structure in a coating film and spray coating, roll coating, dipping coating, It is applied through the comma coating method to increase the heat radiation efficiency to improve the cooling efficiency and serves as a thermal diffusion layer to uniformly transmit heat. Further, it is excellent in workability in shape and gives excellent workability in fine pattern slitting and press working.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a high radiant heat radiation coating material according to an embodiment of the present invention and a method of forming a heat radiation coating film using the same will be described in detail. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are further described in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the 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 terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Thermal spray paint and method for forming heat radiation coating film using the same

The heat radiation coating material having a high radiation function according to an embodiment of the present invention comprises 1 to 10% by weight of carbon nanotubes having a functional group introduced on its surface, 5 to 40% by weight of ceramic powder, a polyester resin 30 having a hydroxy group By weight to 60% by weight of a curing resin, 5 to 10% by weight of a curing resin, 0.01 to 0.2% by weight of a heat initiator and an excess of an organic solvent.

Carbon nanotubes having a functional group introduced thereinto are produced by reacting a carboxyl group on the surface of a carbon nanotube modified by acid treatment with a monomer having an oxirane group, and a substance having a double bond, which is a functional group, Is introduced. A technique for a carbon nanotube having a functional group introduced on the surface thereof is disclosed in Patent Application No. 10-2007-0141638, and a detailed description thereof will be omitted.

The carbon nanotubes into which the functional groups are introduced have high thermal conductivity, which is one of the intrinsic properties of the carbon nanotubes, and can serve as a bridge between the heat-dissipating ceramic powders in which the carbon nanotubes are used together due to the functional groups. That is, the compatibility and dispersibility of the ceramic powder can be increased, and the amount of the ceramic powder that can be dispersed in the resin can be increased more than ever.

If the content of the carbon nanotubes into which the functional group is introduced is less than 1% by weight based on the total amount of the coating material, heat dissipating and dispersing workability with the resin is lowered and the amount of the ceramic powder used can not be increased. If the amount is more than 10% by weight, there is a problem that the production cost increases without increasing the compatibility and dispersing effect of the ceramic powder. Accordingly, it is preferable that the carbon nanotubes into which the functional group is introduced are used in the range of 1 to 10% by weight.

The ceramic powder, which is the ceramic powder to which the present invention is applied, is used to improve the heat radiation property by the pores between the particles. Examples of the ceramic powder include silicon carbide, aluminum oxide, magnesium oxide, tin oxide, silicon nitride, boron nitride and the like. These may be used singly or in a mixture of two or more.

The ceramic powder preferably has an average particle diameter of 1 to 20 μm. When the amount of the ceramic powder is less than 5% by weight, the thermal conductive network is insufficient to constitute the heat conduction network.

The polyester resin having a hydroxy group is a resin suitable for processing workability and shape and has a glass transition temperature of 10 to 40 占 폚, a number average molecular weight of 7,000 to 15,000, a polyester having a hydroxyl value of 10 to 40 It is preferable to use a resin. If the amount of the hydroxyl group-containing polyester resin is less than 30% by weight, physical properties such as adhesiveness and bending property are deteriorated, resulting in peeling of the coating film during shaping. If the amount thereof is more than 60% by weight, the thermal conductivity is lowered and the heat radiation performance is deteriorated. Accordingly, the polyester resin having a hydroxy group is preferably used in an amount of 30 to 60% by weight.

A melamine resin or a urea curing resin may be used for lowering the firing temperature and improving hardness and stain resistance with the curing resin of the present invention.

Examples of the melamine resin include isobutylated melamine resin, methylated melamine resin, and n-butylated melamine resin, and specific examples thereof include CYMEL 325 and CYMEL 327 manufactured by Saitec Corporation.

As the urethane curable resin, one or more isocyanates such as MDI, HDI, and TDI may be used, and a block-shaped product may be used so as to be suitable for the baking temperature.

When the content of the cured resin is less than 5% by weight, the effect is insignificant. When the amount of the cured resin is more than 10% by weight, physical properties such as impact resistance and bending property are deteriorated. Therefore, it is preferable that the curing resin is used in the range of 5 to 10% by weight when the heat radiation paint is produced.

The thermal initiator of the present invention is used to perform the carbon nanotube curing reaction in which the functional group of the double bond is introduced into the above functional group. The thermal initiator may be a peroxide initiator and an azo initiator. Specifically, azobisisobutylonitrile, benzoyl peroxide, di-t-butyl peroxide, tertiary-butyl perbenzoate, methyl ethyl ketone peroxide and the like can be used. The thermal initiator is preferably used in a range of 0.01 to 0.1% by weight based on the total weight of the heat radiation paint.

The organic solvent to be applied to the heat radiating paint may be a mixture of a high boiling organic solvent selected from butyl cellosolve, cellosolve acetate and propyl glycol methyl ether acetate, and a medium boiling point organic solvent selected from xylene and toluene. It is preferable to use it in the range of 10 to 50% by weight.

When a heat radiating paint having the above composition is coated on a target body and then thermally cured, a heat radiating coating film having excellent heat radiating ability can be formed.

When coating a surface of a target such as an electronic part with the above-mentioned composition, the coating method is not particularly limited, but it can be formed by coating with a spraying method, a dipping method, a comma method, a gravure coating method, or the like. At this time, it is preferable to coat the heat radiating paint on the surface of the object with a thickness of 30 to 50 탆, and if it is coated above the thickness, there is a possibility of cost rise and cracking, and if it is lower than that, good heat radiation performance can not be exhibited.

In the firing process for thermally curing the heat radiation coating material in forming the heat radiation coating layer, it is preferable to heat the material at 130 to 160 ° C for 30 to 10 minutes.

The heat-radiating coating film formed by the above-described method can be formed on the surface of a target of various metal materials such as aluminum, copper, and stainless steel, and is excellent in heat-radiating property and adhesiveness as well as in flexibility.

Hereinafter, the present invention will be described in detail by way of examples, but the scope of the present invention is not limited by the examples.

Example 1

50 wt% of a polyester resin having a hydroxy group, 3 wt% of carbon nanotubes into which a functional functional group was introduced, 8 wt% of melamine resin, 1.5 wt% of carbon, 7 wt% of butyl cellosolve, 7 wt% of methyl isobutyl ketone, 12.5% by weight of propylene glycol methyl ether acetate, 3% by weight of boron nitride, 7% by weight of silicon carbide and 1% by weight of a dispersant additive were added and stirred to prepare a heat radiating paint. A heat-radiating sheet was prepared by coating the entire surface of the aluminum sheet with a thickness of 35 mu m.

Comparative Example 1

A heat-radiating sheet made of an aluminum sheet having a thickness of 0.4T was provided without coating the heat-radiating paint.

Comparative Example 2

Except that the carbon nanotubes to which the functional group was introduced in Example 1 were replaced by 50 wt% of polyester resin, 8 wt% of melamine resin, 1.5 wt% of carbon, 7 wt% of butyl cellosolve, 7 wt% of methyl isobutyl ketone, 12.5 wt% of methyl ether acetate, 3 wt% of boron nitride, 7 wt% of silicon carbide, and 1 wt% of a dispersing additive were added, and a heat radiation coating material was prepared through stirring and dispersion processes. A heat radiation sheet was prepared by coating the entire surface of the material with a thickness of 35 탆.

Evaluation of heat radiation measurement of heat-radiating sheet

12 W LED bars were operated on the heat dissipation seeks of Example 1 and Comparative Examples 1 and 2. Temperature changes of the heat dissipation sheet and the LED bar were measured using an OTR sensor. The temperature measurement was performed by measuring the temperature of the initial start time and the temperature after 2 hours at intervals of 30 minutes. The analysis of the heat radiation performance is evaluated as the smaller the difference between the start temperature and the temperature after 2 hours, and the smaller the temperature difference between the LED and the heat radiation sheet, the better the thermal conductivity and heat dissipation. The heat radiation measurement is evaluated in a constant temperature chamber, and the temperature of the constant temperature room is maintained at 25 占 폚. The evaluation results are shown in Table 1 below. Datapaq (Ver7.3) OTR (Oven Tracking Recorder) was used as temperature measurement equipment.

[Table 1]

As shown in Table 1, in Example 1, the heat release sheet having the heat radiation coating of the present invention had an initial temperature of 25.5 ° C after 2 hours and a temperature of 44.3 ° C. In the case of the heat radiation sheet of Comparative Example 1, Thereafter, it was confirmed that Example 1 had a lower temperature difference of 6.5 占 폚 than Comparative Example 2 at 50.8 占 폚. That is, it was confirmed that the heat dissipation effect of Example 1 was 6.5 ° C higher than that of Comparative Example 1. In the case of Comparative Example 2 (the composition excluding the carbon nanotubes into which the functional group of Example 1 was introduced) and Example 1, the heat radiation sheet of Example 1 to which the heat radiation coating material of the present invention was applied at a temperature difference of 4 캜 was heat- I can see that it is excellent.

Claims (8)

A heat dissipation coating for forming a heat dissipation coating on a surface of an electric, electronic component and a heat dissipation sheet,
1 to 10% by weight of carbon nanotubes to which a functional group is introduced on the surface;
5 to 40% by weight of ceramic powder:
30 to 60% by weight of a polyester resin having a glass transition temperature in the range of 10 to 40 占 폚, a number average molecular weight of 7,000 to 15,000 and a hydroxyl value of 10 to 40 and a hydroxyl group;
5 to 10% by weight of a curing resin;
0.01 to 0.2% by weight of a thermal initiator; And
Including an excess of organic solvent,
The carbon nanotubes to which the functional groups are introduced on the surface are prepared by reacting carboxyl groups on the surface of the carbon nanotubes modified by the acid treatment with monomers containing oxirane groups. The carbon nanotubes include a carbon double bond group that is a functional group on the surface Wherein the heat-radiating coating material is a heat-dissipating coating material. delete The heat radiating paint according to claim 1, wherein the ceramic powder comprises at least one selected from the group consisting of aluminum oxide, magnesium oxide, tin oxide, hydrocarbon, boron nitride and silicon nitride. delete The heat radiating paint according to claim 1, wherein the curing resin is any one selected from a melamine resin and a block isocyanate resin. Coating a heat radiating coating material on the object;
Thermally curing the radiation coating material coated on the surface of the object,
1 to 10% by weight of carbon nanotubes prepared by reacting a carboxyl group on the surface of a carbon nanotube surface modified by an acid treatment with a monomer containing an oxirane group and containing carbon double bond groups having functional groups on the surface; 5 to 30% by weight of a ceramic powder; 30 to 60% by weight of a polyester resin having a glass transition temperature in the range of 10 to 40 占 폚, a number average molecular weight of 7,000 to 15,000 and a hydroxyl value of 10 to 40 and a hydroxyl group; 5 to 10% by weight of a curing resin; 0.01 to 0.2% by weight of a heat initiator, and an excess of an organic solvent. [7] The method of claim 6, wherein the heat radiation coating film is formed by applying any one coating method selected from spray coating, roll coating, dipping coating, comma coating, gravure coating and electrodeposition coating. The method of claim 6, wherein the object is any one selected from a heat dissipation component, a heat radiation sheet, a heat sink, and a metal sheet.