WO2020101230A1 - Feuille de graphite très épaisse et son procédé de production - Google Patents

Feuille de graphite très épaisse et son procédé de production Download PDF

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WO2020101230A1
WO2020101230A1 PCT/KR2019/014578 KR2019014578W WO2020101230A1 WO 2020101230 A1 WO2020101230 A1 WO 2020101230A1 KR 2019014578 W KR2019014578 W KR 2019014578W WO 2020101230 A1 WO2020101230 A1 WO 2020101230A1
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graphite sheet
firing
sheet
graphite
firing step
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PCT/KR2019/014578
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English (en)
Korean (ko)
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민재호
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에스케이씨코오롱피아이 주식회사
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Priority claimed from KR1020180141545A external-priority patent/KR102151508B1/ko
Priority claimed from KR1020190081478A external-priority patent/KR20200057595A/ko
Application filed by 에스케이씨코오롱피아이 주식회사 filed Critical 에스케이씨코오롱피아이 주식회사
Publication of WO2020101230A1 publication Critical patent/WO2020101230A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
    • C04B35/524—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite obtained from polymer precursors, e.g. glass-like carbon material
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B

Definitions

  • the present invention relates to a highly thick graphite sheet and a method for manufacturing the same.
  • Graphite is a material with excellent thermal conductivity, and natural graphite and artificial graphite exist, and both of them are in the spotlight as heat dissipation means.
  • artificial graphite is relatively inexpensive and easy to manufacture and process in the form of a thin sheet. , Compared to the thermal conductivity of copper or aluminum, it has about 2 to 7 times better thermal conductivity, and thus is preferably used as a heat dissipation means applied to electronic devices.
  • Typical problems include those that directly affect the performance of electronic devices, such as a decrease in the computation speed of a semiconductor due to the heat load of the electronic device or a shortening of the life due to battery deterioration.
  • a high-thickness graphite sheet having a relatively thick thickness for example, 40 ⁇ m or more.
  • Such a high-thickness graphite sheet is advantageous in terms of heat capacity compared to a conventional thin graphite sheet, for example, a graphite sheet having a thickness of 30 ⁇ m or less, so that even when the heating value of the electronic device is large, heat can be dissipated more efficiently. There is an advantage.
  • the graphite sheet may be prepared through a carbonization process and a graphitization process of a polymer, and among the polymers, a polyimide (PI), a heat-resistant polymer capable of withstanding a temperature of about 400 ° C. or higher, may be used as a graphite precursor.
  • PI polyimide
  • a heat-resistant polymer capable of withstanding a temperature of about 400 ° C. or higher may be used as a graphite precursor.
  • a graphite sheet using polyimide In the manufacture of a graphite sheet using polyimide, heat treatment is performed in an ultra-high temperature environment in the form of film to sublimate non-carbon materials such as oxygen, nitrogen, additives, and other materials except carbon.
  • the main principle is to convert the precursor polyimide into graphite, which is a crystal of carbon, and thick in proportion to a desired high-fuel level in the production of high-thickness graphite sheets.
  • a high-thickness polyimide film having a thickness of 100 ⁇ m or more may be used.
  • An object of the present invention is to provide a high-thickness graphite sheet and a method for manufacturing the same, which can solve the conventional problems described above.
  • the method of manufacturing a graphite sheet includes a firing step having different temperature ranges, in which a thick, high-thickness polyimide film can be graphitized in an optimal state as an essential factor for solving the conventional problem.
  • Each firing step includes an elevated temperature rate optimized therefor as an essential process condition in which a high-fuel polyimide film can be graphitized in an optimal state.
  • the present invention provides a graphite sheet, and the graphite sheet of the present invention has a thickness of 40 ⁇ m or more, in particular 60 ⁇ m or more, particularly in particular a thickness of 70 ⁇ m or more, and the surface quality is high. Excellent, and has excellent thermal conductivity of 500 W / m ⁇ K to 1000 W / m ⁇ K.
  • the present invention has a practical purpose to provide a specific embodiment thereof.
  • a graphite sheet formed by carbonizing and graphitizing a polyimide film the thickness of the graphite sheet is at least about 40 ⁇ m, and the thermal conductivity is about 500 W / m ⁇ K to about 1000 W / m ⁇ K And the number of surface defects per unit area (10 mm * 10 mm) is 5 or less.
  • the graphitization proceeds in a stepwise firing comprising a first firing, a second firing and a final firing, and can satisfy the following expressions 1 and 2:
  • S 1 is the heating rate at the first firing (°C / min)
  • S 2 is the heating rate at the second firing (°C / min)
  • the first firing is performed for about 350 min to about 500 min in the range of about 1,200 ° C to about 2,200 ° C
  • the second firing is about 330 min in the range of about 2,200 ° C to about 2,500 ° C
  • the final firing may be performed for about 10 min to about 50 min in the range of about 2,500 ° C to about 2,800 ° C.
  • it may be prepared by further comprising the step of cooling the graphite sheet at a rate of about 5 ° C / min to about 10 ° C / min from the highest temperature established in the stepwise firing to room temperature.
  • the carbonization may be at a temperature below about 1,250 ° C. and below the first firing temperature.
  • the thickness of the polyimide film can be at least about 100 ⁇ m.
  • the thickness of the graphite sheet can be at least about 60 ⁇ m.
  • the polyimide film may be prepared by imidizing a precursor composition comprising a polyamic acid in which at least one type of dianhydride monomer and at least one type of diamine monomer are polymerized.
  • the precursor composition may further include a sublimable filler selected from the group consisting of calcium carbonate, dicalcium phosphate, and barium sulfate.
  • the precursor composition may have a viscosity of about 90,000 cP or more to about 500,000 cP or less.
  • the present invention comprises the steps of carbonizing a polyimide film at a temperature of about 1,250 ° C. or less to produce a sheet preform comprising an amorphous carbon body formed by thermally decomposing a polyimide polymer chain;
  • the graphitization includes a plurality of firing steps of heat-treating the sheet preform at different heating rates
  • It provides a method for manufacturing a graphite sheet, wherein the thickness of the graphite sheet is at least about 40 ⁇ m, and the number of surface defects per unit area (10 mm * 10 mm) is 5 or less.
  • the firing step includes: a first firing step of heat-treating the sheet preform by heating in a range of about 1,200 ° C. to about 2,200 ° C .; A second firing step of heating the sheet preheater by heating in a range of about 2,200 ° C to about 2,500 ° C after the first firing step; And after the second firing step may include a final firing step of heat treatment in the range of about 2,500 ° C to about 2,800 ° C to heat the sheet preform.
  • the first firing step may be heated to a rate of about 1 °C / min to about 5 °C / min.
  • the second firing step may be heated to a rate of about 0.4 °C / min to about 1.5 °C / min.
  • the final firing step may be heated to a rate of about 9.0 °C / min to about 20 °C / min.
  • the first firing step is heat treatment for about 350 min to about 500 min
  • the second firing step is heat treatment for about 330 min to about 480 min
  • the final firing step is about 10 min to about It can be heat treated for 50 min.
  • the carbonization may be at a rate of about 1 ° C / min to about 10 ° C / min from room temperature to any temperature selected from the range of about 1,200 ° C to about 1,250 ° C.
  • after the firing step may further include the step of cooling the graphite sheet.
  • the cooling step may be cooling the graphite sheet at a rate of about 5 ° C / min to about 10 ° C / min from the highest temperature formed in the firing step to room temperature.
  • the thickness of the polyimide film may be at least about 100 ⁇ m.
  • the thickness of the graphite sheet may be at least about 60 ⁇ m.
  • the polyimide film may be prepared by imidizing a precursor composition comprising a polyamic acid in which at least one type of dianhydride monomer and at least one type of diamine monomer are polymerized.
  • the precursor composition may further include a sublimable filler selected from the group consisting of calcium carbonate, dicalcium phosphate, and barium sulfate.
  • Example 1 is a photograph of a graphite sheet prepared according to Example 1.
  • dianhydride dianhydride
  • dianhydride is intended to include its precursors or derivatives, which may not technically be dianhydrides, but nevertheless react with diamines to form polyamic acids. And this polyamic acid can be converted back to polyimide.
  • Diamine as used herein is intended to include precursors or derivatives thereof, which may not technically be diamines, but will nevertheless react with dianhydrides to form polyamic acids, which are polyamic The acid can be converted back to polyimide.
  • the graphitization may include a plurality of firing steps of heat-treating the sheet preform at different heating rates
  • the thickness of the graphite sheet thus prepared is at least about 40 ⁇ m, in particular at least about 60 ⁇ m, and the number of surface defects per unit area (10 mm * 10 mm) is 5 or less.
  • the thickness of the polyimide film used for the production of the graphite sheet may be preferably at least about 100 ⁇ m, more preferably at least about 120 ⁇ m, particularly preferably at least about 125 ⁇ m. For example, it may be about 100 ⁇ m to about 1,000 ⁇ m.
  • a graphite sheet having a thickness of at least about 40 ⁇ m, particularly at least about 60 ⁇ m, can be obtained.
  • it may be about 40 ⁇ m to about 1,000 ⁇ m.
  • the graphitization proceeds in a stepwise firing comprising a first firing, a second firing and a final firing, and can satisfy the following expressions 1 and 2:
  • S 1 is the heating rate at the first firing (°C / min)
  • S 2 is the heating rate at the second firing (°C / min)
  • S T / S 1 according to Equation 1 may be about 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8 .
  • S 1 / S 2 according to Equation 2 may be about 2, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 4.5, 5, 5.5 or 6.
  • the first firing is performed for about 350 min to about 500 min in the range of about 1,200 ° C to about 2,200 ° C
  • the second firing is about 330 min in the range of about 2,200 ° C to about 2,500 ° C
  • the final firing may be performed for about 10 min to about 50 min in the range of about 2,500 ° C to about 2,800 ° C.
  • the carbonization is from about 1 ° C / min to about 10 ° C / min, particularly about 1 ° C / min to about 1,200 ° C to any temperature selected from the range of about 1,200 ° C to about 1,250 ° C. 5 °C / min, in particular, it may be to increase the temperature at a rate of about 1 °C / min to about 3 °C / min. For example, the temperature may be raised at a rate of about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 ° C / min.
  • the sheet preform thus manufactured may be graphitized at a higher temperature than carbonization to be manufactured in the form of a sheet containing graphite, which will be described in detail below.
  • graphitization While graphitization is performed, graphitization may proceed rapidly in the surface layer of the sheet preform, while graphitization may proceed slowly in the center of the sheet preform or adjacent to the surface layer. That is, the graphitization rate and the degree of graphitization in the surface layer may show a large deviation from that in the inner side.
  • This difference may be more severe in sheet preforms derived from high-thickness polyimide films, which are thicker sheet preforms compared to the thin sheet preforms derived from conventional polyimide films, such as the surface and the inside (eg, Because the distance between, and the center) is longer, heat transfer to the inside is relatively not easy, and since more carbon is contained, more heat energy is required for graphitization of the surface and the adjacent portion, and thus heat energy transferred to the inside It is presumed to be due to the large halving.
  • the inner side adjacent to the center may mean a part of the sheet preform between the top and bottom surfaces when the sheet preform includes the top and bottom surfaces of a pair of faces having the largest area among the surfaces forming the outer surface thereof. .
  • an inner portion of the sheet preform that occupies about 5% by volume to about 90% by volume (based on the total volume of the sheet preform), in particular The inner portion occupying about 5% by volume to about 50% by volume, the central portion of the weight being included as a part, more specifically the inner portion occupying about 5% to about 20% by volume, including the central portion of the weight of the seat preform as a part It can be part.
  • the present invention provides a first firing step and a second firing in different temperature ranges, both of which can be graphitized in an optimal state on both the surface and the inside of a sheet preform derived from a high-thickness polyimide film. It provides a manufacturing method comprising a step and a final firing step.
  • the method of manufacturing a graphite sheet according to the present invention comprises the steps of: carbonizing a polyimide film at a temperature of about 1,250 ° C. or less to prepare a sheet preform comprising an amorphous carbon body formed by thermally decomposing a polyimide polymer chain; And graphitizing the sheet preform to prepare a graphite sheet comprising graphite formed by carbon-rearrangement of the amorphous carbon body, wherein the graphitization comprises a plurality of firings of heat treatment of the sheet preform at different heating rates.
  • the thickness of the graphite sheet is at least about 40 ⁇ m, and the number of surface defects per unit area (10 mm * 10 mm) is 5 or less.
  • the firing step includes: a first firing step of heat-treating the sheet preform by heating in a range of about 1,200 ° C. to about 2,200 ° C .;
  • a final firing step of heating the sheet preform by heating in a range of about 2,500 ° C to about 2,800 ° C may be included.
  • the first calcination step to the final calcination step may be performed sequentially, and the temperature range applied to each calcination step depends on the graphitization rate and graphitization degree of the surface and inside of the sheet preform when the sheet preform is fired. By minimizing the occurrence of variations, it can result in obtaining a quality graphite as a result.
  • the first firing step from about 1,200 °C to about 2,200 °C, specifically from 1,200 °C to about 2,200 °C to about 1 °C / min to about 5.5 °C / min, in detail from about 1 °C / min to about 5 °C / min, in particular, it may be a step of inducing graphitization of the sheet preform while heating at a rate of about 1.5 ° C / min to about 4.5 ° C / min. For example, the temperature may be raised at a rate of about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or 5.5 ° C / min.
  • a graphite structure may be formed while at least a part of the amorphous carbon body constituting the sheet preform has relatively high crystallinity and thermal decomposition and carbon-rearrangement are performed.
  • uniform heat energy can be transferred throughout the sheet preform, and the transferred heat energy accumulates in the sheet preform, which remains in the sheet preform in the subsequent firing step, that is, graphite.
  • the remaining amorphous carbon body eg, about 95% by weight to about 99.9% by weight
  • the remaining amorphous carbon body may be a step to help convert to graphite.
  • the temperature range of the first firing step is a desirable range in which these phenomena can be optimally expressed.
  • the rate of temperature increase applied to the first firing step may be optimally applied to apply heat energy substantially equal to the surface to the inside of the sheet preform at any suitable temperature, in connection with the temperature range.
  • the graphitization rate, the degree of graphitization, heat energy transfer, and heat energy accumulation on the surface and the inside of the sheet preform may play a major role in achieving a balanced implementation.
  • the gas generated by sublimation of a substance other than carbon present in the sheet preliminary body may be exhausted, discharged, and released from the sheet preliminary body, a pre-formed graphite structure on the surface, a graphite structure in the process of being formed, and / or A portion of the amorphous carbon body may be physically destroyed or damaged by a sublimation gas generated in large quantities from the inside.
  • the crystal structure of the graphite sheet finally obtained is not uniform, which may lead to a decrease in thermal conductivity, and is easily broken as the sheet surface and / or the inside of the sheet has a non-uniform graphite layer. Due to this, surface defects such as protrusions may be caused.
  • the second firing step is from about 0.4 °C / min to about 1.5 °C / min from about 2,200 °C to about 2,500 °C, specifically about 0.4 °C / min to about 1.3 °C / min, in particular about 0.4 °C / min It may be a step of further inducing graphitization of the sheet preform while heating at a rate of about 1.25 ° C./min. For example, while heating to about 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4 or °C / min, it may be a step of further inducing graphitization of the sheet preform.
  • the second firing step among the amorphous carbon bodies constituting the sheet preform, at least a portion having a relatively high crystallinity may undergo pyrolysis and carbon-rearrangement to form a graphite structure.
  • amorphous carbon body eg, about 90% to about 99.9% by weight
  • the remaining amorphous carbon body may be an additional step to help convert to graphite.
  • the temperature range of the second firing step is a desirable range in which these phenomena can be optimally expressed.
  • the rate of temperature rise in the second firing step may be optimally applied to apply heat energy substantially equal to the surface to the inside at any temperature, in connection with the temperature range, and consequently, to the surface and inside of the sheet preform.
  • the rate of graphitization, level of graphitization, heat energy transfer, and heat energy accumulation can act advantageously to be implemented in a balanced manner.
  • the gas generated by sublimation of a substance other than carbon present in the sheet preliminary body may be exhausted, discharged, and released from the sheet preliminary body.
  • the graphite structure, and / or a portion of the amorphous carbon body may be physically destroyed or damaged by sublimation gas generated in a large amount inside.
  • the crystal structure of the graphite sheet finally obtained is not uniform, which may lead to a decrease in thermal conductivity, and the sheet surface and / or the inside of the sheet has a non-uniform graphite structure, making it brittle, and due to exhaustion of a large amount of sublimation gas Surface defects such as pinholes or protrusions may be caused.
  • the final calcination step is from about 2,200 °C to about 2,800 °C, in particular from about 2,200 °C to about 2,700 °C, more specifically from about 2,200 °C to about 2,650 °C from about 7.0 °C / min to about 20 °C / min, details Temperature of about 8.5 ° C / min to about 20 ° C / min, more specifically about 9 ° C / min to about 20 ° C / min, particularly specifically about 9 ° C / min to about 17.5 ° C / min , It may be a step of further inducing the graphitization of the sheet preform, in particular, substantially completing the graphitization.
  • almost all of the amorphous carbon body of the sheet preform e.g., about 98% to about 99.9% by weight
  • substantially all of the amorphous carbon body of the sheet preform is graphite, regardless of the crystallinity of the carbon body. Converted to, to form a graphite sheet.
  • sufficient heat energy according to the heating rate specific to these steps in the preceding first firing step and the second firing step can proceed in a state that is accumulated on the surface and inside of the sheet preform, so that it is more than the previous firing step.
  • the firing can proceed at a fast heating rate.
  • the heating rate exceeds the above range, the graphitization of the final firing step may not be uniformly performed in each part of the sheet preform, so that the graphite sheet intended in the present invention may not be realized.
  • the amorphous carbon body may belong to all stages of a graphite structure having crystallinity by thermal energy already accumulated during the first firing step and the second firing step. Some of the carbon due to may be missing amorphous, may be structurally unstable. If, under a slow heating rate outside the above range, a large number of carbons of the amorphous carbon body in the previous step are gradually rearranged, the structurally unstable state is maintained for a long time, and accordingly, the structure collapses as described above. I guess.
  • both the first firing step and the second firing step proceed at a relatively slow speed
  • the final firing step proceeds with graphitization relatively rapidly, which is due to the prevention of the above-mentioned harmful effects, thereby providing high quality graphite. It can act as a decisive factor in obtaining the sheet.
  • the first firing step is heat treatment for about 350 min to about 500 min
  • the second firing step is heat treatment for about 330 min to about 480 min
  • the final firing step is about 10 min to about It can be heat treated for 50 min.
  • the heat treatment process above or below the above range is not preferable as it may cause excessive graphitization or insufficient graphitization, which may lead to a deterioration in the quality of the resulting graphite sheet.
  • the manufacturing method of the present invention may further include a step of cooling the graphite sheet after the firing step, and the surface properties of the graphite sheet obtained by such cooling may be improved.
  • the cooling step of the maximum temperature formed in the firing step in particular about 2,800 °C, more specifically about 2,700 °C, in particular from about 2,650 °C to about room temperature from about 5 °C / min to about 10 °C / min Cooling the graphite sheet at a rate may be a step.
  • the graphite sheet can be cooled at a rate of about 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 ° C / min from about 2,650 ° C to room temperature.
  • a polyimide film that can be used for the production of a graphite sheet according to the present invention is prepared by imidizing a precursor composition comprising a polyamic acid in which at least one type of dianhydride monomer and at least one type of diamine monomer are polymerized.
  • a precursor composition comprising a polyamic acid in which at least one type of dianhydride monomer and at least one type of diamine monomer are polymerized.
  • the polyamic acid in the precursor composition may be prepared by polymerization of one or more diamine monoclonals and one or more dianhydride monomers in an organic solvent.
  • the diamine monomer that can be used for the polymerization of the polyamic acid is an aromatic diamine, and can be exemplified by classifying as follows.
  • 1,4-diaminobenzene or paraphenylenediamine, PDA, PPD
  • 1,3-diaminobenzene 2,4-diaminotoluene
  • 2,6-diaminotoluene 3,5-dia
  • a diamine having one benzene ring in structure such as minobenzoic acid (or DABA), etc., a diamine having a relatively rigid structure
  • Diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxidianiline, ODA), 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane ( Or 4,4'-methylenediamine, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2 ' -Bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'- Diaminodiphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4
  • the dianhydride monomer that can be used for the polymerization of the polyamic acid may be an aromatic tetracarboxylic dianhydride.
  • the aromatic tetracarboxylic dianhydride is pyromellitic dianhydride (or PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (or s-BPDA), 2,3 , 3 ', 4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3', 4'-tetracar Bixyl dianhydride (or DSDA), bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3, 3-hexafluoropropane dianhydride, 2,3,3 ', 4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic
  • the organic solvent is not particularly limited as long as it is a solvent in which the polyamic acid can be dissolved, but as an example, the organic solvent may be an aprotic polar solvent.
  • amide solvents such as N, N'-dimethylformamide (DMF), N, N'-dimethylacetamide (DMAc), p-chlorophenol, o-chloro And phenol-based solvents such as phenol, N-methyl-pyrrolidone (NMP), gamma brotirolactone (GBL) and digrime, and these may be used alone or in combination of two or more.
  • the solubility of the polyamic acid may be controlled by using auxiliary solvents such as toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol, and water.
  • auxiliary solvents such as toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol, and water.
  • organic solvents that can be particularly preferably used for preparing the precursor composition of the present invention may be amide solvents N, N'-dimethylformamide and N, N'-dimethylacetamide.
  • the method for polymerizing the polyamic acid is, for example,
  • Some diamine monomer components and some dianhydride monomer components are reacted in an organic solvent so as to be in excess, thereby forming a first polymer, and some diamine monomer components and some dianhydride monomer components in another organic solvent.
  • a method for reacting such that one is in excess to form a second polymer mixing the first and second polymers, and completing the polymerization, wherein the diamine monomer component is excessive when forming the first polymer.
  • the polyamic acid prepared as described above may have a weight average molecular weight of about 150,000 g / mole or more to about 1,000,000 g / mole or less, and more specifically about 170,000 g / mole or more to about 700,000 g / mole or less, and more specifically It may be about 190,000 g / mole or more to about 500,000 g / mole or less.
  • Polyamic acid having such a weight average molecular weight may be preferable for the production of a polyimide film having better heat resistance and mechanical properties.
  • the weight average molecular weight of the polyamic acid may be proportional to the viscosity of the precursor composition containing the polyamic acid and the organic solvent, and the viscosity may be adjusted to control the weight average molecular weight of the polyamic acid to the above range.
  • the viscosity of the precursor composition is proportional to the content of the polyamic acid solid content, in particular, the total amount of the dianhydride monomer and the diamine monomer used in the polymerization reaction.
  • the weight average molecular weight does not represent a linear linear relationship with respect to viscosity, but is proportional to the logarithmic function.
  • the range in which the weight average molecular weight can be increased is limited while increasing the viscosity in order to obtain a higher weight average molecular weight polyamic acid, when the viscosity is too high, the precursor composition through a die in the film forming process of the polyimide film When discharging, it may cause a processability problem due to an increase in pressure inside the die.
  • the precursor composition of the present invention may include about 15% to about 20% by weight of polyamic acid solids and about 80% to about 85% by weight of an organic solvent, in which case the viscosity is greater than about 90,000 cP to about 500,000 cP or less, specifically, about 150,000 cP or more to about 400,000 cP. Within this viscosity range, the weight average molecular weight of the polyamic acid may fall within the above range, and the precursor composition may not cause problems in the film forming process described above.
  • Preparing a precursor composition containing polyamic acid by introducing one or more dianhydride monomers and one or more diamine monomers into an organic solvent and polymerizing them;
  • the precursor composition may be formed on a support and imidized to obtain a polyimide film.
  • the process of preparing the precursor composition may be performed using the method for preparing the polyamic acid described above, and the diamine monomer, dianhydride monomer, and organic solvent used may also be appropriately selected and used in the examples described above.
  • the imidization process may be performed through a thermal imidization method, a chemical imidization method, or a complex imidization method using a combination of the thermal imidization method and a chemical imidization method.
  • the precursor composition may further include a sublimable filler.
  • the sublimable filler may sublimate during carbonization and / or graphitization of the polyimide film to induce a predetermined foaming phenomenon.
  • a foaming phenomenon can smoothly evacuate the sublimation gas generated during carbonization and / or graphitization, thereby enabling the obtaining of a high-quality graphite sheet, and the predetermined voids formed by foaming have the flexibility of the graphite sheet ( 'Flexibility') can also be improved.
  • the excessive foaming phenomenon and a large number of voids resulting therefrom may significantly deteriorate the thermal conductivity and mechanical properties of the graphite sheet, and may cause defects on the surface of the graphite sheet. Should be chosen.
  • the content of the sublimable filler may be 0.2 parts by weight to 0.5 parts by weight compared to 100 parts by weight of the first polyamic acid.
  • Excess sublimable filler outside the above range may cause excessive foaming during carbonization and graphitization, causing damage to the internal structure of the graphite sheet, and accordingly, the thermal conductivity of the graphite sheet may be lowered, and the graphite sheet surface E, it is not preferable because the number of bright spots, which are traces of foaming, can be significantly increased.
  • the sublimable filler is contained below the above range, it is not preferable because the above-described foaming phenomenon may not be realized in a desired form.
  • the average particle diameter of the sublimable filler may also be selected on the same principle as the significance of the content of the sublimable filler described above, and in detail, the average particle diameter may be about 1.5 ⁇ m to about 4.5 ⁇ m.
  • the sublimable filler having a particle size that is too small below the above range is difficult to induce a desired level of foaming in the carbonization and graphitization processes, and thus, the above-described damage may be caused.
  • Sublimable fillers are not preferred when the average particle diameter exceeds the above range, as they may cause excessive bright spot formation.
  • the sublimable filler may include, for example, one or more inorganic particles selected from the group consisting of dibasic calcium phosphate, barium sulfate, and calcium carbonate, but is not limited thereto.
  • a 0.5 L reactor was mixed and polymerized under nitrogen atmosphere with dimethylformamide (DMF) as an organic solvent, ODA as a diamine monomer, and PMDA as a dianhydride monomer to prepare a solution containing polyamic acid.
  • DMF dimethylformamide
  • ODA organicamine monomer
  • PMDA a dianhydride monomer
  • dibasic calcium phosphate having an average particle diameter of 3 ⁇ m was mixed with a solution containing polyamic acid and stirred to obtain a precursor composition.
  • Betapicoline (BP) and acetic anhydride (AA) were added to the precursor composition prepared as described above, and then uniformly mixed and cast to 500 ⁇ m using a doctor blade on a SUS plate (100SA, Sandvik) and 100 Drying in the temperature range of °C to 200 °C to prepare a gel film having self-support.
  • the gel film was peeled off from the SUS Plate and fixed to a pin frame and transferred to a high-temperature tenter.
  • the film was heated from 200 ° C to 700 ° C in a high-temperature tenter, cooled at 25 ° C, and then separated from a pin frame to obtain a polyimide film having a width * length of 20cm * 20cm and a thickness of 125 ⁇ m.
  • the polyimide film of Preparation Example was heated to 1,210 ° C. at a rate of 3.3 ° C./min under nitrogen gas using an electric furnace capable of carbonization, and maintained at 1,210 ° C. for about 2 hours (carbonization).
  • a first calcination step was performed by heating from 1,210 ° C to 2,200 ° C at a heating rate of 2.5 ° C / min under argon gas using an electric furnace capable of graphitization.
  • the heating rate was changed to a heating rate of 1.25 ° C./min, and the temperature was continuously raised to 2,500 ° C. to perform a second firing step.
  • the heating rate was changed to a heating rate of 10 ° C./min, and the temperature was continuously raised to 2,650 ° C. to perform a final calcination step. After standing at 2,650 ° C. for a few minutes, graphitization was completed to complete the graphite sheet. It was prepared.
  • the graphite sheet was cooled at a rate of 10 ° C./min to obtain a graphite sheet having a thickness of about 70 ⁇ m at room temperature.
  • a graphite sheet having a thickness of about 68 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 12 ° C./min.
  • a graphite sheet having a thickness of about 67 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 9 ° C./min.
  • a graphite sheet having a thickness of about 72 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the first firing step was changed to 4 ° C./min.
  • a graphite sheet having a thickness of about 68 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 20 ° C./min.
  • a graphite sheet having a thickness of about 68 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the second firing step was changed to 1 ° C./min.
  • a graphite sheet having a thickness of about 71 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the second firing step was changed to 0.42 ° C./min.
  • a graphite sheet having a thickness of about 70 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the second firing step was changed to 0.63 ° C./min.
  • a graphite sheet having an average thickness of about 68 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 0.42 ° C./min.
  • a graphite sheet having an average thickness of about 68 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 5 ° C./min.
  • a graphite sheet having an average thickness of about 71 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the final firing step was changed to 22 ° C./min.
  • the average temperature was about 71 ⁇ m in the same manner as in Example 1, except that the second firing step was performed by continuously increasing the temperature to 2,600 ° C. by changing the rate of temperature increase to 0.42 ° C./min.
  • Graphite sheets were prepared.
  • the average temperature was about 69 ⁇ m in the same manner as in Example 1, except that the second firing step was performed by continuously increasing the temperature to 2,550 ° C. by changing the rate of temperature increase to 0.42 ° C./min.
  • Graphite sheets were prepared.
  • a graphite sheet having an average thickness of about 69 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the first firing step was changed to 0.5 ° C./min.
  • a graphite sheet having an average thickness of about 66 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the first firing step was changed to 7 ° C./min.
  • a graphite sheet having an average thickness of about 71 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the second firing step was changed to 0.2 ° C./min.
  • a graphite sheet having an average thickness of about 65 ⁇ m was prepared in the same manner as in Example 1, except that the heating rate of the second firing step was changed to 2 ° C./min.
  • the number of surface defects was confirmed as the number per area of 10 mm * 10 mm.
  • the collapse means that the graphite structure is broken in the form of a powder on the surface and / or inside of the graphite sheet, which is visually confirmed.
  • the average thickness is a value obtained by measuring the thickness 10 times in different parts of the graphite sheet and arithmetic average.
  • the graphite sheet prepared according to the example was made with a high degree of surface defects that is remarkably small and the average thickness of the sheet is 60 ⁇ m or more. In addition, in the Examples, no collapse phenomenon of the graphite structure was observed.
  • Example 1 shows a photograph of a graphite sheet manufactured according to Example 1.
  • FIG. 2 shows a photograph of a graphite sheet manufactured according to Example 3.
  • the graphite sheet shown in FIGS. 1 and 2 was photographed in a plurality of cuts so that the entire sheet of a long length was included in the photograph.
  • the graphite sheet manufactured according to the embodiment of the present invention has a smooth surface characteristic with extremely few surface defects, and the graphite sheet collapses in the form of a powder on the inside and the surface of the sheet to form a sheet structure. There was no incomplete part.
  • FIG. 3 shows a photograph of a graphite sheet prepared according to Comparative Example 1.
  • the graphite sheet of Comparative Example 1 can be confirmed that the graphite structure is broken in the form of a powder on its surface and the inside, which is clearly contrasted with the graphite sheet in shape, shown in FIG.
  • FIG. 4 shows a photograph of the graphite sheet prepared in Comparative Example 2
  • FIG. 5 shows a photograph of the graphite sheet prepared in Comparative Example 5
  • FIG. 6 shows a production in Comparative Example 6 A photograph of an old graphite sheet is shown.
  • the graphite sheet has a characteristic brittle characteristic, so that the shape can hardly be maintained. To the extent it is demonstrated that the graphite structure collapses.
  • FIG. 7 shows a photograph of the graphite sheet manufactured in Comparative Example 4
  • FIG. 8 shows a photograph of the graphite sheet manufactured in Comparative Example 9.
  • Comparative Example 4 is a case in which the graphite sheet was manufactured by using a high temperature increase rate in which the final calcination step is outside the scope of the present invention, and the graphite structures were collapsed as in Comparative Examples 2, 5, and 6 above.
  • Comparative Example 9 is a case in which the graphite sheet was produced at a very slow heating rate outside the scope of the present invention, and the graphite structure collapsed as in Comparative Examples 2, 5, and 6 above.
  • the thermal conductivity of the graphite sheet was measured by a laser flash method using a diffusion rate measurement equipment (model name LFA 467, Netsch), and the specific heat measurement using density (weight / volume) and specific heat (DSC) in the measured values of the thermal diffusion rate Value) to calculate the thermal conductivity.

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Abstract

La présente invention concerne une feuille de graphite très épaisse et son procédé de production. Dans un mode de réalisation spécifique, la feuille de graphite est une feuille de graphite formée par carbonisation et graphitisation d'un film de polyimide, et la feuille de graphite présente une épaisseur d'au moins 40 µm environ, une conductivité thermique d'environ 500 à 1 000 W/m·K et un nombre de défauts de surface par unité de surface (10 mm * 10 mm) inférieur ou égal à 5.
PCT/KR2019/014578 2018-11-16 2019-10-31 Feuille de graphite très épaisse et son procédé de production WO2020101230A1 (fr)

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KR10-2019-0081478 2018-11-16
KR10-2018-0141545 2018-11-16
KR1020180141545A KR102151508B1 (ko) 2018-11-16 2018-11-16 고후도 그라파이트 시트의 제조방법 및 이를 이용하여 제조된 고후도 그라파이트 시트
KR1020190081478A KR20200057595A (ko) 2019-07-05 2019-07-05 고후도 그라파이트 시트

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CN116490570A (zh) * 2020-11-30 2023-07-25 聚酰亚胺先端材料有限公司 石墨片用聚酰亚胺膜、其制造方法和由其制造的石墨片

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JP2013155113A (ja) * 2013-05-20 2013-08-15 Kaneka Corp グラファイトフィルムおよびグラファイトフィルムの製造方法
JP2017043668A (ja) * 2015-08-25 2017-03-02 東レ・デュポン株式会社 ポリイミドフィルム及びその製造方法
KR20170051903A (ko) * 2015-11-03 2017-05-12 코오롱인더스트리 주식회사 그라파이트 필름의 제조방법
KR101826855B1 (ko) * 2016-03-31 2018-03-22 한국화학연구원 흑연 시트의 제조 방법
KR101883434B1 (ko) * 2018-01-30 2018-07-31 에스케이씨코오롱피아이 주식회사 그라파이트 시트용 폴리이미드 필름, 이를 이용하여 제조된 그라파이트 시트 및 그라파이트 시트의 제조방법

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Publication number Priority date Publication date Assignee Title
JP2013155113A (ja) * 2013-05-20 2013-08-15 Kaneka Corp グラファイトフィルムおよびグラファイトフィルムの製造方法
JP2017043668A (ja) * 2015-08-25 2017-03-02 東レ・デュポン株式会社 ポリイミドフィルム及びその製造方法
KR20170051903A (ko) * 2015-11-03 2017-05-12 코오롱인더스트리 주식회사 그라파이트 필름의 제조방법
KR101826855B1 (ko) * 2016-03-31 2018-03-22 한국화학연구원 흑연 시트의 제조 방법
KR101883434B1 (ko) * 2018-01-30 2018-07-31 에스케이씨코오롱피아이 주식회사 그라파이트 시트용 폴리이미드 필름, 이를 이용하여 제조된 그라파이트 시트 및 그라파이트 시트의 제조방법

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116490570A (zh) * 2020-11-30 2023-07-25 聚酰亚胺先端材料有限公司 石墨片用聚酰亚胺膜、其制造方法和由其制造的石墨片

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