KR100975885B1 - Manufacturing method of carbon sheet coated mixed dispersion solvent base on expanded graphite powder - Google Patents

Abstract

PURPOSE: A manufacturing method of a carbon sheet coated mixed dispersion solvent is provided to improve thermal conductivity in a vertical direction which is relatively lower and prevent the exfoliation of the carbon sheet. CONSTITUTION: A manufacturing method of a carbon sheet coated mixed dispersion solvent is comprised of the steps: mixing a first solution operated as a dispersant of 70 parts by weight with a second solution operated as a binder solution of 30 parts by weight to form a third solution of 80-97 parts by weight; mixing one of single-walled carbon nanotube, double-walled carbon nanotube, multi-walled carbon nanotube, carbon nano fiber, nano carbon, grapheme, and fullerene to manufacture a fourth solution; and dispersing the fourth solution and coating the mixed dispersion solution on a expanded graphite sheet.

Description

Manufacturing method of carbon sheet coated mixed dispersion solvent base on expanded graphite powder}

The present invention relates to a mixed carbon sheet coated with a mixed dispersion solution on an expanded graphite sheet and a method of manufacturing the same. More specifically, the mixed dispersion produced by adding a carbon nanowire material, a dispersant, a binder, or the like into the expanded graphite sheet is mixed. It relates to a method for producing a mixed carbon sheet produced by coating a solution on one or both sides of the expanded graphite sheet.

The conventional expanded graphite sheet processing method fills a predetermined press mold with the coated expanded graphite powder.

Then, the expanded graphite powder is press-molded at an appropriate molding pressure using a press to produce a primary workpiece.

Then, if necessary, by rolling the primary workpiece (Rolling) to meet the appropriate target thickness, to produce a secondary workpiece, the secondary workpiece is cut / bent to produce a final carbon sheet.

 The expanded graphite sheet processing method configured as described above operates as follows.

When the expanded graphite powder is filled in the mold, the press applies a constant molding pressure to form the expanded graphite powder.

However, when the carbon sheet is manufactured in this manner, the carbon sheet is weak in strength, so that when a certain pressure or more is applied, the plastic sheet is not only plastically deformed but also has good thermal conductivity (100-400 W / mk) in the horizontal direction, but the voids exist in the carbon sheet. There is a problem that the thermal conductivity in the vertical direction (3 ~ 5W / mk) falls, and furthermore, the conventional carbon sheet has a problem that the price is expensive because it depends on the total amount imported.

Meanwhile, another expanded graphite sheet manufacturing method includes an intercalation process of widening the gap of the graphite layer using sulfuric acid and the like in graphite particles of a predetermined size, and then removing clay material therebetween using hydrofluoric acid, and 600 degrees Celsius. After having an expansion process of 200 to 1000 magnification using a high temperature of ~ 1800 degrees, the expanded graphite flakes were laminated by a vibrator and produced by continuous roll compression, and the expanded graphite sheet produced was peeled off. In order to solve the problem, a protective tape based on pe or pet on one side and a double sided tape based on pe or pet have been used on the other side.

However, when the expanded graphite sheet is manufactured in this way, the voids between the expanded graphite flakes cannot be completely removed during lamination, which causes a problem of partial voids in the sheet and partial voids in the sheet form, and also a peeling problem inherent in graphite. In particular, it has a problem causing surface peeling problems. Due to this problem, the thermal graphite has a high thermal conductivity in the horizontal direction (100-400 W / mk) due to the low density of the expanded graphite sheet, but has a relatively large difference in the thermal conductivity in the vertical direction (3-5 W / mk). .

Meanwhile, the high thermal conductivity carbon sheet using a mixed carbon of expanded graphite and carbon nanotubes, which is filed in Korea and registered in patent 0628031, has expanded graphite powder and carbon nanotubes (CNT, Carbon Nano Tube) mixed at a predetermined mixing ratio. ) A unit carbon sheet layer formed by pressing the powder at high temperature; And a synthetic resin layer formed on at least one surface of the unit carbon sheet layer to reinforce the unit carbon sheet layer and electrically insulate the unit carbon sheet layer.

The high thermal conductivity carbon sheet is a method of manufacturing by high temperature pressurization by mixing between expanded graphite particles and carbon nanotube powder which is not dispersed in a simple powder state. Since the carbon nanotube particles cannot be coated between the expanded graphite particles, thermal conductivity is increased. It cannot be maximized.

In addition, since the graphite layer, the carbon nanotube layer, the adhesive layer, the heat-resistant film layer, the pressure-sensitive adhesive layer, the release layer is formed in the order of high contact resistance for each layer had a problem that can not maximize the thermal conductivity.

The present invention has been made to solve the above problems, an object of the present invention is to improve the thermal conductivity in the vertical direction, as well as to enhance the physical properties and to prevent peeling and to improve the tensile strength and tear strength mixed dispersion solution Is coated on the expanded graphite sheet to fill the voids to improve the strength of the expanded graphite sheet and excellent thermal conductivity.

Another object of the present invention is to prevent the expanded graphite sheet from peeling through the secondary effect of coating the expanded graphite sheet in the process of coating the mixed dispersion solution on the expanded graphite sheet.

In order to achieve the problem to be solved by the present invention,

Method for producing a mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet according to an embodiment of the present invention,

Water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x, hydropropyl A primary solution manufacturing step (S110) of using a solution of one or two or more selected from cellulose and hydroxypropyl methylcellulose to form a primary solution in a predetermined ratio;

Preparing a secondary solution by mixing polyester and urethane at a predetermined ratio with a binder solvent, or preparing a secondary solution by mixing a silane (adhesive enhancer) and an epoxy at a predetermined ratio (S120);

Tertiary solution manufacturing step (S130) of mixing the primary solution and the secondary solution in a predetermined ratio to form a tertiary solution;

Single wall carbon nanotubes, double wall carbon nanotubes, multiwall carbon nanotubes, carbon nanofibers, nanocarbons, graphene, and fullerenes in a tertiary solution are mixed in a predetermined ratio. A fourth solution manufacturing step (S140) for making a tea (final) solution;

Putting the fourth (final) mixed solution into a beaker or a dispersion container, and then dispersing it through an ultrasonic device to produce a mixed dispersion solution (S150);

It characterized in that to produce a mixed carbon sheet including; coating step (S160) for coating the mixed dispersion solution on the expanded graphite sheet.

The mixed carbon sheet coated with the mixed dispersion solution on the expanded graphite sheet according to the present invention having the above configuration and action, and a method of manufacturing the same,

 The mixed carbon sheet manufactured using a mixed dispersion solution containing expanded graphite and carbon nanowires is particularly improved in thermal conductivity in the vertical direction, thereby reducing the difference in thermal conductivity in the horizontal direction and in the vertical direction. It can greatly contribute to improvement.

In addition, in the process of coating the mixed dispersion solution on the expanded graphite sheet through the secondary effect of coating the expanded graphite sheet is improved in tensile strength and tear strength and is effective in preventing the phenomenon of peeling.

Mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet of the present invention for achieving the above object,

Water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulphate, polyvinyl alcohol, triton-x, hydropropyl Using a solution of one or two or more selected from cellulose, hydroxypropyl methyl cellulose to make a ratio of the primary solution,

As a binder solvent, a urethane-based solution in which polyester and urethane are mixed at a predetermined ratio, or a silane (adhesive enhancer) and an epoxy-based mixture are mixed at a predetermined ratio to make a secondary solution,

After mixing the primary solution and the secondary solution in a predetermined ratio to form a tertiary solution,

Single wall carbon nanotubes, double wall carbon nanotubes, multiwall carbon nanotubes, carbon nanofibers, nanocarbons, graphene, and fullerenes in a tertiary solution are mixed in a predetermined ratio. After making tea (final) solution,

The fourth (final) mixed solution is placed in a beaker or a dispersion container, and then dispersed through an ultrasonic apparatus to prepare a mixed dispersion solution, and coated with a mixed dispersion solution on the expanded graphite sheet.

At this time, instead of the ultrasonic device,

At least one of a ball milling method, a grinding method, a grinding method, a three roll milling method, and a high energy ball milling method is used.

On the other hand, the mixed carbon sheet manufacturing method of coating the mixed dispersion solution on the expanded graphite sheet,

Water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x, hydropropyl A primary solution manufacturing step (S110) of using a solution of one or two or more selected from cellulose and hydroxypropyl methylcellulose to form a primary solution in a predetermined ratio;

Preparing a secondary solution by mixing polyester and urethane at a predetermined ratio with a binder solvent, or preparing a secondary solution by mixing a silane (adhesive enhancer) and an epoxy at a predetermined ratio (S120);

Tertiary solution manufacturing step (S130) of mixing the primary solution and the secondary solution in a predetermined ratio to form a tertiary solution;

Single wall carbon nanotubes, double wall carbon nanotubes, multiwall carbon nanotubes, carbon nanofibers, nanocarbons, graphene, and fullerenes in a tertiary solution are mixed in a predetermined ratio. A fourth solution manufacturing step (S140) for producing a tea (final) solution;

Putting the fourth (final) mixed solution into a beaker or a dispersion container, and then dispersing it through an ultrasonic device to produce a mixed dispersion solution (S150);

It characterized in that to produce a mixed carbon sheet including; coating step (S160) for coating the mixed dispersion solution on the expanded graphite sheet.

At this time, in the coating step,

The mixed dispersion solution to be coated has a thickness of 0.2 μm to 5 μm, and the coating is performed using at least one of a roll coating, a knife coating method, or a spray coating method. It is done.

At this time, in the primary solution manufacturing step (S110),

In the case of making a primary solution using two or more solutions, 50 parts by weight of each of the selected dispersants may be mixed.

At this time, in the secondary solution manufacturing step (S120),

In case of making a secondary solution by mixing polyester and urethane, 80 parts by weight of urethane is mixed in 20 parts by weight of polyester, or 2 parts by weight of silane in case of making a secondary solution by mixing silane and epoxy in a ratio. It is characterized by mixing 98 parts by weight of epoxy-based.

At this time, in the third solution manufacturing step (S130),

It is characterized by mixing 30 parts by weight of the prepared secondary solution in 70 parts by weight of the prepared primary solution.

At this time, in the fourth solution manufacturing step (S140),

From 97 parts by weight to 80 parts by weight of the tertiary solution, 3 parts by weight of carbon nanowires selected from single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, nanocarbon, graphene, and fullerene 20 parts by weight, or when the two selected carbon nanowires, characterized in that the mixture of 1.5 parts by weight to 10 parts by weight of each selected carbon nanowires.

Hereinafter, the mixed carbon sheet coated with the mixed dispersion solution on the expanded graphite sheet according to the present invention will be described in detail through an embodiment of the method.

1 is a process chart of a mixed carbon sheet manufacturing method of coating a mixed dispersion solution on the expanded graphite sheet according to an embodiment of the present invention.

The present invention is to apply the mixed dispersion solution to any one or both sides of the expanded graphite sheet placed in the working position, and then placed in a roll press that can control the molding pressure and molding thickness in the working position, and repeat the rolling process It is characterized in that the final product is pressed to the required target thickness, and the final workpiece can provide a mixed carbon sheet having excellent thermal conductivity in the horizontal and vertical direction.

As shown in Figure 1, the mixed carbon sheet manufacturing method of coating the mixed dispersion solution on the expanded graphite sheet of the present invention,

Water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x, hydropropyl A primary solution manufacturing step (S110) of using a solution of one or two or more selected from cellulose and hydroxypropyl methylcellulose to form a primary solution in a predetermined ratio;

A secondary solution manufacturing step (S120) of preparing a secondary solution by mixing a urethane-based solution or a silane (adhesive enhancer) and an epoxy-based epoxy resin in a predetermined ratio as a binder solvent;

A tertiary solution manufacturing step (S130) of mixing the primary solution and the secondary solution at a predetermined ratio to form a tertiary solution;

Single wall carbon nanotubes, double wall carbon nanotubes, multiwall carbon nanotubes, carbon nanofibers, nanocarbons, graphene, and fullerenes in a tertiary solution are mixed in a predetermined ratio. A fourth solution manufacturing step (S140) for making a tea (final) solution;

Putting the fourth (final) mixed solution into a beaker or a dispersion container, and then dispersing it through an ultrasonic device to produce a mixed dispersion solution (S150);

It characterized in that to produce a mixed carbon sheet including; coating step (S160) for coating the mixed dispersion solution on the expanded graphite sheet.

The primary solution manufacturing step (S110) is to make a primary solution of a certain ratio using one or two or more selected solutions.

That is, for example, water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulphate, polyvinyl alcohol, When one or two or more solutions selected from triton-x, hydropropyl cellulose, and hydroxypropyl methyl cellulose are used to make a proportion of the primary solution, one ethyl alcohol can be selected, and if ethyl alcohol and acetone are selected, To prepare a primary solution by mixing 50 parts by weight of acetone to 50 parts by weight of ethyl alcohol.

The secondary solution manufacturing step (S120) is a binder solution, for example, a polyester and urethane mixed in a predetermined ratio, for example, to make a secondary solution by a urethane-based solution mixed with 80 parts by weight of urethane 20 parts by weight of polyester, A silane (adhesive enhancer) and an epoxy-based mixture are mixed at a predetermined ratio, for example, by mixing 98 parts by weight of an epoxy-based 2 parts by weight of silane to make a secondary solution.

In the tertiary solution manufacturing step (S130), the primary solution and the secondary solution are mixed at a predetermined ratio, for example, by mixing 30 parts by weight of the secondary solution with 70 parts by weight of the prepared primary solution. Will be made.

The fourth solution manufacturing step (S140) is one or two selected from single-wall carbon nanotubes, double-walled carbon nanotubes multi-walled carbon nanotubes, carbon nanofibers, nanocarbon, graphene, fullerene in the tertiary solution The above carbon nanowires are mixed in a predetermined ratio to form a fourth (final) solution.

For example, when carbon nanofibers are selected and mixed with the tertiary solution (when one is selected), 3 parts by weight to 20 parts by weight of carbon nanofibers are mixed with 97 parts by weight to 80 parts by weight of the prepared tertiary solution.

That is, when 97 parts by weight of the tertiary solution is selected, 3 parts by weight of carbon nanofibers are mixed.

On the other hand, in the case of selecting and mixing carbon nanofibers and nanocarbon in the tertiary solution (when selecting two), the carbon nanofibers 1.5 parts to 10 parts by weight of 97 parts by weight to 80 parts by weight of the prepared tertiary solution , 1.5 to 10 parts by weight of nanocarbon is to be mixed.

That is, when 97 parts by weight of the tertiary solution is selected, 1.5 parts by weight of carbon nanofibers and 1.5 parts by weight of nanocarbon are mixed.

In the step of preparing the mixed dispersion solution (S150), the fourth (final) mixed solution is placed in a beaker or a dispersion container, and then dispersed through an ultrasonic apparatus to prepare a mixed dispersion solution.

In this case, at least one of a ball milling method, a grinding method, a three roll milling method, and a high energy ball milling method may be used instead of the ultrasonic device.

After the above step is coated on the expanded graphite sheet, the thickness of the mixed dispersion solution 200 is formed to a thickness of about 0.2㎛ to 5㎛, as shown in Figure 2, the roll coating (Roll Coating) Alternatively, the coating may be performed by using a knife coating method or a spray coating method.

The mixed carbon sheet according to the present invention refers to a sheet in which a mixed dispersion solution containing carbon nanowires is coated on a surface of the surface of the mixed dispersion solution.

This can maximize the thermal conductivity by reducing the voids on the original expanded graphite sheet 100, and also penetrates the pores and the surface of the surface using a ceramic-based or polymer resin of nanoparticles, thereby acting as an adhesive between the carbon The improvement of thermal conductivity and peeling can be prevented, and electrical insulation can be provided on the sheet surface.

In the prior art, graphite particles of a certain size were produced by continuous compression after intercalation and expansion, and the produced sheet was polyethylene or PE on one side thereof to solve the peeling problem. A protective tape based on (polyethylen terephthalate) and a double sided tape based on polyethylene (PE) or polyethylen terephthalate have been used on the other side.

However, when photographing the monolayer and the surface of the expanded graphite sheet with an electron microscope, many pores are formed when the expanded graphite particles are laminated. The very voids reduce the thermal and electrical conductivity.

Especially in the vertical direction it falls further. In order to solve this problem, by using carbon nanowires much smaller than the size of expanded graphite particles to be located in the pores, the density can be made higher, and better thermal and electrical conductivity can be improved. By placing such carbon nanowires in the wire, the efficiency of the conductivity can be further maximized, and the peeling phenomenon can be significantly reduced.

In addition, when the carbon nanowires and the nano-particles of ceramic or polymer resins are mixed and dispersed and coated on the surface thereof, an exfoliation problem and an electrical short may be solved.

        The carbon nanowires include any one or more of single wall carbon nanotubes, double wall carbon nanotubes, multiwall carbon nanotubes, carbon nanofibers, nanocarbon, graphene, and fullerene.

The dispersant may be water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x One or two or more solutions selected from hydropropyl cellulose and hydroxypropyl methylcellulose are used.

In addition, the binder material, which is one of the main raw materials of the dispersing additive, uses a urethane-based solution in which polyester and urethane are mixed at a constant ratio, or an epoxy-based solution in which silane (adhesive reinforcing material) and epoxy are mixed at a constant ratio.

The mixed dispersion solution coating layer is formed to a thickness of about 0.2 ㎛ to 5 ㎛, it can be coated by any one of a roll coating (Roll coating) and knife coating (Knife Coating).

For reference, roll coating refers to coating a mixed dispersion solution on one surface of the expanded graphite sheet through a roller. Knife coating refers to coating a predetermined amount of mixed dispersion solution on one surface of the expanded graphite sheet. It refers to coating by spreading thinly to a proper thickness using a knife.

As shown in FIG. 3, it can be seen that when the coating layer of the mixed dispersion solution is further formed, a higher heat dissipation effect can be induced.

For reference, the thermal conductivity of the expanded graphite sheet having the mixed dispersion solution coating layer was found to be higher in heat dissipation effect than that of the expanded graphite sheet.

Those skilled in the art to which the present invention pertains as described above may understand that the present invention may be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not restrictive.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

The mixed carbon sheet coated with the mixed dispersion solution on the expanded graphite sheet of the present invention is judged to have excellent functionality as a heat sink in the industrial field of next-generation flat panel display devices such as LCD, PDP, LED, and the like. PC, notebook, netbook, mobile devices It will be utilized in heat sinks of automobiles, heat sinks of home appliances, and the like.

1 is a process chart of a mixed carbon sheet manufacturing method of coating a mixed dispersion solution on the expanded graphite sheet according to an embodiment of the present invention.

2 is an exemplary view showing an example in which the mixed dispersion solution formed by the mixed carbon sheet manufacturing method of coating the mixed dispersion solution on the expanded graphite sheet according to an embodiment of the present invention is coated on the expanded graphite sheet.

Figure 3 is a view showing the thermal properties of the mixed carbon sheet prepared by the method for producing a mixed carbon sheet coated with a mixed dispersion solution on the expanded graphite sheet according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: expanded graphite sheet

200: mixed dispersion solution

Claims (8)

70 parts by weight of the primary solution as a dispersant was mixed with 30 parts by weight of a secondary solution as a binder solvent to form a tertiary solution as a mixed solution, and 80 parts by weight to 97 parts by weight of the single wall carbon nanotube and double wall carbon nano After mixing 3 parts by weight to 20 parts by weight of one selected from a tube, multi-walled carbon nanotubes, carbon nanofibers, nanocarbon, graphene, and fullerene, a mixture made by dispersing the fourth solution The dispersion solution is coated on the expanded graphite sheet, The primary solution is water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x , Hydropropyl cellulose, hydroxypropyl methyl cellulose is a method for producing a mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet, characterized in that any one selected from. delete 70 parts by weight of the primary solution as a dispersant was mixed with 30 parts by weight of a secondary solution as a binder solvent to form a tertiary solution as a mixed solution, and 80 parts by weight to 97 parts by weight of the single wall carbon nanotube and double wall carbon nano After mixing 3 parts by weight to 20 parts by weight of one selected from a tube, multi-walled carbon nanotubes, carbon nanofibers, nanocarbon, graphene, and fullerene, a mixture made by dispersing the fourth solution The dispersion solution is coated on the expanded graphite sheet, The primary solution is water or ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl isoketone, ethylene glycol, aniline, toluene, chloroform sodium dodecyl sulfate, polyvinyl alcohol, triton-x Mixed hydrocarbon sheet coated with a mixed dispersion solution in the expanded graphite sheet, characterized in that the two solutions selected from the mixture, hydropropyl cellulose, hydroxypropyl methyl cellulose, 50 parts by weight of each of the two selected solutions Manufacturing method. The method according to claim 1 or 3, The secondary solution is a method of manufacturing a mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet, characterized in that 80 parts by weight of urethane mixed with 20 parts of polyester. The method according to claim 1 or 3, The secondary solution is a method of manufacturing a mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet, characterized in that the mixture 98 parts by weight of epoxy based on 2 parts by weight of silane. The method according to claim 1 or 3, The thickness of the mixed dispersion solution coated on the expanded graphite sheet is 0.2 μm to 5 μm, and is coated using at least one of a roll coating, a knife coating method, or a spray coating method. Method for producing a mixed carbon sheet coated with a mixed dispersion solution to the expanded graphite sheet, characterized in that to perform. delete delete

Images