KR20170074586A - Method for preparing roll type graphite sheet - Google Patents

Method for preparing roll type graphite sheet Download PDF

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KR20170074586A
KR20170074586A KR1020150184035A KR20150184035A KR20170074586A KR 20170074586 A KR20170074586 A KR 20170074586A KR 1020150184035 A KR1020150184035 A KR 1020150184035A KR 20150184035 A KR20150184035 A KR 20150184035A KR 20170074586 A KR20170074586 A KR 20170074586A
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South Korea
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sheet
curing
coating
carbonization
heat treatment
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KR1020150184035A
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Korean (ko)
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KR101809641B1 (en
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박종휘
김정규
서정두
견명옥
백종갑
박기륜
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에스케이씨 주식회사
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    • C01B31/043—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H37/00—Article or web delivery apparatus incorporating devices for performing specified auxiliary operations
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2039—Modifications to facilitate cooling, ventilating, or heating characterised by the heat transfer by conduction from the heat generating element to a dissipating body
    • H05K7/20436—Inner thermal coupling elements in heat dissipating housings, e.g. protrusions or depressions integrally formed in the housing
    • H05K7/20445—Inner thermal coupling elements in heat dissipating housings, e.g. protrusions or depressions integrally formed in the housing the coupling element being an additional piece, e.g. thermal standoff
    • H05K7/20472—Sheet interfaces
    • H05K7/20481—Sheet interfaces characterised by the material composition exhibiting specific thermal properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00—Handling processes for sheets or webs
    • B65H2301/50—Auxiliary process performed during handling process
    • B65H2301/51—Modifying a characteristic of handled material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00—Handling processes for sheets or webs
    • B65H2301/50—Auxiliary process performed during handling process
    • B65H2301/51—Modifying a characteristic of handled material
    • B65H2301/516—Securing handled material to another material
    • B65H2301/5162—Coating, applying liquid or layer of any material to material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/10—Handled articles or webs
    • B65H2701/17—Nature of material
    • B65H2701/171—Physical features of handled article or web
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/10—Handled articles or webs
    • B65H2701/17—Nature of material
    • B65H2701/174—Textile, fibre
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2701/00—Handled material; Storage means
    • B65H2701/10—Handled articles or webs
    • B65H2701/17—Nature of material
    • B65H2701/177—Fibrous or compressible material
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/32—Thermal properties
    • C01P2006/37—Stability against thermal decomposition

Abstract

The present invention provides a process for producing a graphite sheet in the form of a roll, in which a curing step is carried out in a heat treatment apparatus and a coating and curing step is a continuous process. The present invention also relates to a process for producing a graphite sheet in the form of a roll, wherein the curing step, the carbonization step and the graphitization step are continuously performed in a heat treatment apparatus, and the coating step, the curing step, A process for producing a roll-shaped graphite sheet comprising a continuous process.
The method of producing a roll-shaped graphite sheet according to the present invention is a method in which a curing, carbonization and / or graphitization process is continuously performed in one heat treatment apparatus, thereby not only improving productivity but also suppressing surface irregularities, A graphite sheet can be obtained. By producing the graphite sheet in the form of a roll, it is excellent in storage and transportability, and it is economical because loss can be reduced during punching. By using fibers such as cotton fibers or rayon as the base component, it is possible to produce a graphite sheet which is excellent in thermal conductivity in the horizontal and vertical directions, can be produced at a low manufacturing cost, is economically advantageous, have.

Description

METHOD FOR PREPARING ROLL TYPE GRAPHITE SHEET [0002]

The present invention relates to a process for producing a graphite sheet in the form of a roll using fibers as a base component and more particularly to a process for producing a graphite sheet comprising a curing step, a carbonization step and / or a graphitization step, Which is carried out continuously.

In recent years, electronic devices have become highly integrated with thin, thin and multifunctional devices, and heat dissipation has been demanded. It is also important that the release of heat is closely related to the reliability and lifetime of the device. Accordingly, a variety of heat dissipation materials have been developed and marketed in the form of a heat dissipation pad, a heat dissipation sheet, and a heat dissipation paint, thereby supplementing or replacing existing heat dissipation fans, heat dissipation fins, and heat pipes.

Among them, the heat-radiating sheet is manufactured in the form of a graphite sheet, a polymer-ceramic composite sheet, a multilayered coating metal thin film sheet, etc. In the case of a graphite sheet, lightweight, slim and thermal conductivity is extremely high, And a PDP constituting a plasma television or the like.

However, the graphite sheet is generally produced by pyrolysis of a polymer film. Since the graphite sheet is similar to a single crystal, its breaking strength and tensile strength are low, and the heat transfer is made in the horizontal direction by the principle of thermal diffusion, There is a problem that the heat radiation effect is not sufficiently obtained because the thermal conductivity in the vertical direction (thickness direction) is low. In addition, shrinkage and expansion occur in the heat treatment process. When a gap or space is generated between raw film layers at the time of shrinkage and unevenness is generated on the surface through such a gap or space at the time of expansion, surface roughness becomes poor and physical properties of the graphite sheet There was a problem of deterioration.

Thus, the inventors of the present invention have succeeded in obtaining a graphite sheet which not only has improved productivity but also has surface unevenness suppressed and is excellent in flatness, by continuously performing the hardening step, the carbonization step and / or the graphitization step in one heat treatment apparatus, It has been found that, by making the graphite sheet in the form of a roll, it is excellent in storability and transportability, and it is economical because loss can be reduced during punching. Further, it has been found that by using cotton fibers or fibers such as rayon as the base component, it is possible to produce a product having a high thermal conductivity in the horizontal and vertical directions at a low manufacturing cost, thereby being economically advantageous and also excellent in flexibility.

Accordingly, an object of the present invention is to provide a process for producing a graphite sheet in the form of a roll, which not only improves productivity, but also has excellent storability and transportability, suppresses surface irregularities and has excellent flatness and excellent thermal conductivity in horizontal and vertical directions, And to provide a graphite sheet produced therefrom.

In order to accomplish the above object, the present invention provides a method for producing a sheet, comprising the steps of: (1) coating a cross-section or both sides of a fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) carbonizing the cured sheet to produce a carbonized sheet; And (4) a graphitizing step of graphitizing, the curing step being carried out in a heat treatment apparatus, and the coating and curing step being a continuous process.

(1) a coating step of coating a cross-section or both sides of the fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) carbonizing the cured sheet to produce a carbonized sheet; And (4) a graphitizing step, wherein the curing step, the carbonization step and the graphitization step are continuously performed in a heat treatment apparatus, and the coating step, the curing step, the carbonization step and the graphitization step are continuously performed The present invention provides a method for producing a graphite sheet in the form of a roll.

The method of producing a graphite sheet in the form of a roll according to the present invention is advantageous in that not only the productivity is improved but also the surface irregularity is suppressed and the flatness is improved by continuously performing the hardening step, the carbonization step and / or the graphitization step in one heat treatment apparatus An excellent graphite sheet can be obtained. By making the graphite sheet in the form of a roll, it is excellent in storability and transportability, and it is economical because loss can be reduced in punching. By using fibers such as cotton fibers or rayon as the base component, it is possible to produce a graphite sheet which is excellent in thermal conductivity in the horizontal and vertical directions, can be produced at a low manufacturing cost, is economically advantageous, have.

Figs. 1 and 2 schematically show a method of producing a roll-shaped graphite sheet according to an embodiment of the present invention.
3 schematically shows a state in which the winding core is rotated in a direction opposite to the winding direction after the cured sheet is wound, according to an embodiment of the present invention.
Figs. 4 and 5 schematically show a state in which a wound film is charged into a crucible and carbonized and graphitized, according to an embodiment of the present invention.
Fig. 6 schematically shows the appearance of a cured sheet wound with a cured sheet and a graphite powder wound together with a masking film or a separator in an embodiment of the present invention. Fig.
7 schematically shows a state in which an induction heating coil is disposed outside a crucible in which a wound cured sheet is loaded, according to an embodiment of the present invention.
Fig. 8 shows the temperature distribution in the crucible depending on the presence or absence of the center column when the crucible is inductively heated, according to an embodiment of the present invention.

(1) a coating step of coating a cross-section or both sides of a fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) carbonizing the cured sheet to produce a carbonized sheet; And (4) a graphitizing step of graphitizing, the curing step being carried out in a heat treatment apparatus, and the coating and curing step being a continuous process.

(1) a coating step of coating a cross-section or both sides of the fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) carbonizing the cured sheet to produce a carbonized sheet; And (4) a graphitizing step, wherein the curing step, the carbonization step and the graphitization step are continuously performed in a heat treatment apparatus, and the coating step, the curing step, the carbonization step and the graphitization step are continuously performed The present invention provides a method for producing a graphite sheet in the form of a roll.

Fiber substrate

In the method of producing a graphite sheet in the form of a roll according to the present invention, the fiber substrate may comprise natural fibers, artificial fibers or paper.

The fibrous base material may be made of natural fibers, and natural fibers constituting the fibrous base material may be roughly divided into cellulose fibers, protein fibers and mineral fibers. The cellulosic fibers may be selected from the group consisting of (i) seed fibers such as cotton or kapok, (ii) stem fibers such as flax, hemp, hemp or jute, (iii) fruit fibers such as coconut fibers, and (iv) Or leaf fibers such as sisal. In addition, the protein fibers include (i) wool fibers, (ii) silk fibers, and (iii) hair fibers. When the base material constituting the graphite sheet according to the present invention is made of natural fibers, it is preferable that the natural fibers are at least one natural fiber selected from the group consisting of cotton, hemp, wool and silk.

The fibrous base material may be formed of a synthetic fiber, and the synthetic fibers constituting the fibrous base material may be roughly divided into an organic fiber and an inorganic fiber. The organic fibers may be selected from the group consisting of (i) regenerated fibers including cellulose-based fibers and protein-based fibers such as rayon, tencel (lyocell), or modal, (ii) semisynthetic fibers including cellulosic fibers such as acetate or triacetate, (iii) a synthetic fiber such as a polyamide fiber, a polyester fiber, a polyurethane fiber, a polyethylene fiber, a polyvinyl chloride fiber, a polyfluoroethylene fiber, a polyvinyl alcohol fiber, an acrylic fiber or a polypropylene fiber . In the case where the fiber substrate constituting the graphite sheet according to the present invention is made of a synthetic fiber, the synthetic fiber is preferably composed of nylon, polyester, polyurethane, polyethylene, polyvinyl chloride, polyfluoroethylene, polyvinyl alcohol, acrylic and polypropylene And at least one synthetic fiber selected from the group consisting of When the base material constituting the graphite sheet according to the present invention is made of artificial fiber, it is preferable that the artificial fiber is at least one kind of cellulose fiber selected from the group consisting of rayon, acetate and triacetate.

The fibrous substrate may be paper.

Polymer resin

In the graphite sheet according to the present invention, the polymer is not particularly limited, but may be polyamic acid, polyimide, polyamide, polyvinyl chloride, polyester, polyurethane, polyethylene, polypropylene, polyfluoroethylene, polyvinyl alcohol, Acrylic, polyoxadiazole, polybenzoxazole, polyacrylonitrile, and the like, preferably polyamic acid, polyimide, polyamide or polyvinyl chloride.

In addition, the polymer resin may include a carbonized polymer. The carbonized polymer is prepared by heat-treating the polymer resin in an atmosphere of an inert gas such as nitrogen or argon, and contains carbon in an amount of 90 wt% or more.

Coating step

In the process for producing a graphite sheet according to the present invention, the coating may be carried out in various conventional coating processes, for example, a roll coating process, a rolling process, a bar coating process, a dip coating (immersion coating) process , A spray coating process, a cast coating process, an extrusion coating process, or the like. In one embodiment of the present invention, when a liquid polyamic acid having a high viscosity is used, a rolling process may be used to effectively coat the fibrous substrate, but the present invention is not limited thereto. Can be used.

In addition, in the coating step, the thickness ratio of the fibrous base material and the coated polymer resin is preferably 1: 9 to 9: 1. Further, in one embodiment of the present invention, after the coating step, a rolling step of rolling the sheet may be further included to improve the uniformity of the coating thickness.

Further, when tensile force is applied to the fibrous substrate in the coating step, the pulling tension (N / m) applied to the fibrous substrate may be 1 to 10 N / m.

Heat treatment apparatus

In the process for producing a graphite sheet according to the present invention, the curing step, the carbonization step and / or the graphitization step may be continuously performed in one heat treatment apparatus 40. The heat treatment apparatus 40 for curing, carbonizing and / or graphitizing the sheet 12 may be composed of a plurality of heating units 41, 41 ', 41' '. In order to uniformly heat the sheet, it is preferable that the temperature distribution in one heating section be uniformly maintained, and in order to avoid a sudden temperature change in the heat treatment apparatus 40, one heating section has a gentle temperature gradient ). Further, a heater or a heat insulating material can be disposed to control the temperature distribution in the heat treatment apparatus.

The heating units 41, 41 ', 41' 'may be composed of a plurality of, for example, two or more and up to 100 or less. The length of each of the heating sections may be not less than 5 cm, not less than 10 cm, not less than 20 cm, or not less than 50 cm so that sufficient heat can be applied to the sheet 12 to be continuously passed.

Further, in order to gently heat the sheet 12, it is preferable that the temperature of the heating section located behind the heating section located in front of the plurality of heating sections is high. Further, when a gentle temperature gradient is given in one heating section, it is preferable that the temperature at the outlet of the heating section is higher than the temperature at the inlet of the heating section. For example, it is preferable that the temperature of the heating part 41 'is higher than the temperature of the heating part 41 of FIG. 2, and the temperature of the heating part 41' is higher than the temperature of the heating part 41 '.

Further, the heat treatment apparatus 40 may have a cooling section if necessary, and the cooling section may be positioned at the end of the final heating section or between the heating sections as necessary. The cooling portion is a space for cooling the sheet heated by the heating portion, and an effect of suppressing the occurrence of wrinkles can be obtained. The temperature of the cooling section is lower than the temperature of the immediately preceding heating section and is 550 ° C or lower, 500 ° C or lower, 450 ° C or lower, 300 ° C or lower, preferably 100 ° C or lower. The length of the cooling section may be 50 cm or more, 1 m or more, 2 m or more, or 5 m or more so that the sheet to be continuously passed can be sufficiently cooled.

<When the curing step is performed continuously in one heat treatment apparatus>

Curing step

In one embodiment of the present invention, when the curing step is carried out continuously in a heat treatment apparatus, it may be carried out in a heat treatment apparatus having a temperature range of 80 to 400 DEG C, 0.0 &gt; g., &Lt; / RTI &gt;

The pulling tension applied to the sheet in the curing step is preferably 1 to 10 N / m so as to suppress generation of wrinkles due to heat and to prevent breakage due to excessive tension.

Coiling  step

In the method of producing a rolled graphite sheet according to the present invention, after the curing step, it may include a winding step of winding the cured sheet in the form of a roll, and may optionally further include a rolling step before the winding step have. The winding device 50 used in the winding step is not particularly limited as long as it is provided at the exit of the heat treatment device and can wind the cured sheet. In one embodiment of the present invention, after the curing step, the pulling tension T (N / m) of the cured sheet is preferably adjusted to 1 to 10 N / m. When the pulling tension is adjusted to the above range, it is possible to prevent the cured sheet from being stretched or wrinkled, and it is possible to prevent breakage of the cured sheet due to fusion and excessive tension. Further, in one embodiment of the present invention, it is preferable that the rate of change of the traction tension is controlled to be less than ± 5%, preferably less than ± 3%.

As shown in Fig. 3, in the winding step, the winding core 51 is rotated in a direction opposite to the winding direction after winding to prevent a space between the cured sheets, as shown in Fig. 3, in order to prevent the cured sheets from fusing to each other or preventing blocking phenomenon . When the cured sheet is wound, a masking film such as a polyolefin film or a polyester film, or a separator may be stacked and wound together, and the thickness of the masking film or separator is preferably 25 to 3000 mu m. In addition, fusing and blocking phenomenon can be prevented by spraying the graphite powder on one side of the cured sheet to be wound.

Carbonization step

In the method for producing a graphite sheet according to the present invention, the wound cured sheet is formed into a graphite sheet through a heat treatment process through a carbonization and / or a graphitization step. The heat treatment step in the carbonization step can be carried out after the wound cured sheet is charged into the crucible. The crucible is provided with pressing means for preventing a phenomenon that a rolled rolled cured sheet is shrunk during heat treatment to cause a gap or a space between the cured sheet layers, Can be mounted.

The wound cured sheet charged into the crucible is charged into the crucible with the winding core 51 removed. In addition, the wound cured sheet is inserted into the center column 52 having a diameter of about 70%, about 80%, or about 90% based on the inner diameter of the cured sheet wound on the place where the winding core 51 is removed And can be charged into the crucible. In other words, the central column 52 having a diameter of 70 to 90% is positioned based on the inner diameter of the cured sheet wound around the center of the crucible. When the central column 52 having a diameter of about 70% to 90% is inserted based on the inner diameter of the rolled cured sheet, the temperature distribution in the crucible is made uniform during the heat treatment process of carbonization and graphitization, The temperature difference can be made small. In addition, a shrinkage phenomenon of the sheet wound in the heat treatment process occurs, and it is possible to prevent cracks caused by a reduction in the inner diameter of the sheet wound by the shrinkage phenomenon. Therefore, it is preferable that the center pillar 52 has a diameter of about 70 to 90% based on the inner diameter of the wound sheet in order to prevent cracks caused by shrinkage of the wound sheet .

The carbonization step of the present invention is preferably carried out in an inert gas such as nitrogen or argon, and may be carried out at a temperature ranging from 400 to 2500 ° C. In one embodiment of the present invention, the carbonization step is performed at a temperature in the range of 800 ° C to 1800 ° C, more specifically, in a temperature range of 1000 ° C to 1400 ° C for about 30 minutes For 20 hours, more specifically about 1 to 4 hours, to carbonize the cured sheet.

Graphitization  step

The graphitization step is preferably performed in an inert gas such as nitrogen or argon, and may be performed at a temperature of about 2500 DEG C or higher or a temperature of about 3200 DEG C or lower. In one embodiment of the present invention, the graphitization step may be carried out at a temperature of about 2500 ° C to 3000 ° C, specifically at a temperature of about 2600 ° C to 2900 ° C, more specifically about 2600 ° C to 2700 ° C . As the heat treatment temperature is increased, the degree of graphitization is improved, but the process cost is increased. Further, the heat treatment in the graphitization step may be performed for about 30 minutes to 20 hours, more specifically about 30 minutes to 4 hours, and the pressure condition may be in the range of 700 to 760 torr, but is not limited thereto.

The carbonization and / or graphitization step may be performed by resistance heating, arc heating or induction heating, so that the carbonization and / or graphitization step may proceed in a resistance heating furnace, an arc heating furnace, or an induction heating furnace.

The induction heating is an electromagnetic induction principle in which a current flows in a closed circuit by a temporally varying magnetic field. When a coil is disposed around a heating object such as a conductor to allow an alternating current to flow, It is a phenomenon that heat is generated by heat loss and loss of hysteresis. As an embodiment of the present invention, the induction heating may be performed by disposing an induction heating coil 62 outside a crucible in which a wound cured sheet is loaded, and inducing heating of the cured sheet by supplying a current to the induction heating coil have.

&Lt; Curing, Carbonization and Graphitization Steps are Performed Successively in One Heat Treatment Apparatus >

Hardening, carbonization and Graphitization  step

In one embodiment of the present invention, the curing step, the carbonization step and the graphitization step may be performed continuously in the heat treatment apparatus, in which case the temperature range may be 80 to 3200 占 폚. In addition, the temperature in the heat treatment apparatus may have a gentle temperature gradient over the entire temperature range.

The pulling tension applied to the sheet during the curing, carbonization and graphitization steps is preferably 1 to 10 N / m so as to suppress generation of wrinkles due to heat and to prevent breakage due to excessive tension.

Coiling  step

In the method of producing a graphite sheet in the form of a roll according to the present invention, after the curing, carbonization and graphitization steps, it may include a winding step of winding the sheet 13 'into a roll form, A rolling step may be further included. The winding device 50 used in the winding step is not particularly limited as long as it is provided at the exit of the heat treatment device and can wind the cured sheet. In one embodiment of the present invention, after the curing, carbonization and graphitization steps, the pulling tension T of the sheet 13 is preferably adjusted to 1 to 10 N / m. When the pulling tension is adjusted to the above range, the phenomenon that the carbonized sheet is stretched or wrinkled can be suppressed, and breakage due to fusion and excess tension of the carbonized sheet can be prevented. Further, in one embodiment of the present invention, it is preferable that the rate of change of the traction tension is controlled to be less than ± 5%, preferably less than ± 3% .

Hereinafter, the present invention will be described in more detail with reference to the following examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example

Example 1

(1) Preparation step of description

100 plain yarn (150X100) (origin: China) was prepared as a fiber base material.

(2) Coating step

A liquid polyamic acid was coated on one side of the fiber substrate using a roll coating process at 25 캜 to prepare a sheet.

(3) Curing step

The sheet thus prepared was dried and cured for 30 minutes by a hot air curing method in a heat treatment apparatus having a temperature gradient of 80 ° C to 250 ° C to prepare a cured sheet.

(4) Coiling step

The thus-prepared cured sheet was wound 10 times and then unwound by one turn.

(5) Carbonization and graphitization step

The rolled sheet was charged into a graphite crucible, carbonized at a temperature of 1200 ° C for 2 hours, and then graphitized at a temperature of 2800 ° C for 1 hour to prepare a graphite sheet having a thickness of 40 μm.

Example 2

A graphite sheet having a thickness of 40 占 퐉 was produced in the same manner as in Example 1 except that 140 carbon fibers were used instead of 100 cotton fabrics of Example 1. [

Experimental Example 1: Heat diffusion test

The graphite sheets prepared in the above examples were measured for thermal diffusivity using a laser flash method (NEIZCH LFA447). The results are summarized in Table 1 below.

division Example 1 Example 2 Thermal diffusivity (mm 2 / s) 530 520

As shown in the above table, the graphite sheet according to the present invention exhibits a thermal diffusivity of about 520 to 530 mm 2 / s, and exhibits the same or superior thermal diffusivity as that of the conventional graphite sheet. In addition, since the graphite sheet according to the present invention uses relatively inexpensive cotton fiber as a base component, it can be produced at a considerably lower production cost than the conventional graphite sheet, and the manufacturing cost can be greatly reduced, which is economical.

11: fiber substrate 12, 13, 13 ': sheet
20: Coating device 30: Rolling device
40: heat treatment apparatus 41, 41 ', 41'':
50: winding device 51: winding core
60: Crucible 61: Crucible cap
62: induction heating coil

Claims (20)

(1) a coating step of coating a cross-section or both sides of a fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) carbonizing the cured sheet to produce a carbonized sheet; And (4) a graphitizing step of graphitizing,
Wherein the curing step is performed in a heat treatment apparatus, and the coating and curing step is a continuous process.
The method according to claim 1,
Wherein the fiber base material is natural fiber, artificial fiber or paper.
3. The method of claim 2,
Wherein the fiber base material is at least one natural fiber selected from the group consisting of cotton, hemp, wool, and silk.
The method according to claim 1,
Wherein the polymer resin comprises a polyamic acid.
The method according to claim 1,
Wherein the thickness ratio of the fibrous base material to the coated polymer resin is 1: 9 to 9: 1.
The method according to claim 1,
Further comprising a rolling step of rolling the sheet after the coating step.
The method according to claim 1,
Wherein the pulling tension applied in the coating step and the curing step is 1 to 10 N / m.
The method according to claim 1,
Wherein the curing step is performed in a heat treatment apparatus in a temperature range of 80 to 400 占 폚.
The method according to claim 1,
Further comprising a winding step of winding the cured sheet after the curing step.
10. The method of claim 9,
Wherein the pulling tension applied to the cured sheet in the winding step is 1 to 10 N / m or less.
11. The method of claim 10,
Wherein the rate of change of the pulling tension is less than +/- 5%.
10. The method of claim 9,
And in the winding step, the cured sheet is wound together with a masking film or a separator.
10. The method of claim 9,
The method of producing a roll-shaped graphite sheet as claimed in claim 1, wherein in the winding step, graphite powder is sprayed onto one surface of the cured sheet.
The method according to claim 1,
Wherein the carbonization step is carried out at a temperature in the range of 400 to 2500 占 폚.
The method according to claim 1,
Wherein the graphitization step is performed in a temperature range of 2500 to 3200 캜.
The method according to claim 1,
Wherein carbonization of the cured sheet is carried out in a crucible and a central column having a diameter of 70 to 90% is located based on an inner diameter of the cured sheet wound around the center of the crucible.
(1) a coating step of coating a cross-section or both sides of a fiber substrate with a polymer resin to produce a sheet; (2) a curing step of curing the polymer resin coated on the fiber substrate to produce a cured sheet; (3) a carbonization step of carbonizing the cured sheet; And (4) a graphitizing step of graphitizing,
Wherein the curing step, the carbonization step and the graphitization step are continuously performed in a heat treatment apparatus, and the coating step, the curing step, the carbonization step and the graphitization step are continuous processes.
18. The method of claim 17,
Wherein the curing step, the carbonization step and the graphitization step are performed in a heat treatment apparatus in a temperature range of 80 to 3200 ° C.
18. The method of claim 17,
Wherein the pulling tension applied in the coating step, the curing step, the carbonization step and the graphitization step is 1 to 10 N / m.
20. The method of claim 19,
Wherein the rate of change of the pulling tension is less than +/- 5%.
KR1020150184035A 2015-12-22 2015-12-22 Method for preparing roll type graphite sheet KR101809641B1 (en)

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