CN115894998A - High-thermal-conductivity polyimide film and preparation method thereof - Google Patents
High-thermal-conductivity polyimide film and preparation method thereof Download PDFInfo
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- CN115894998A CN115894998A CN202211695734.7A CN202211695734A CN115894998A CN 115894998 A CN115894998 A CN 115894998A CN 202211695734 A CN202211695734 A CN 202211695734A CN 115894998 A CN115894998 A CN 115894998A
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- 238000002360 preparation method Methods 0.000 title claims abstract description 19
- 239000002002 slurry Substances 0.000 claims abstract description 26
- 239000000945 filler Substances 0.000 claims abstract description 23
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 21
- 239000010959 steel Substances 0.000 claims abstract description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 20
- 238000001035 drying Methods 0.000 claims abstract description 17
- 239000004952 Polyamide Substances 0.000 claims abstract description 13
- 239000002253 acid Substances 0.000 claims abstract description 13
- 229920002647 polyamide Polymers 0.000 claims abstract description 13
- 230000004048 modification Effects 0.000 claims abstract description 9
- 238000012986 modification Methods 0.000 claims abstract description 9
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 7
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 7
- 238000005266 casting Methods 0.000 claims abstract description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 42
- 229920005575 poly(amic acid) Polymers 0.000 claims description 40
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 38
- 229910052582 BN Inorganic materials 0.000 claims description 34
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- GTDPSWPPOUPBNX-UHFFFAOYSA-N ac1mqpva Chemical compound CC12C(=O)OC(=O)C1(C)C1(C)C2(C)C(=O)OC1=O GTDPSWPPOUPBNX-UHFFFAOYSA-N 0.000 claims description 28
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 18
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 15
- 229940113088 dimethylacetamide Drugs 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 15
- 150000004985 diamines Chemical class 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 239000006185 dispersion Substances 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 238000001914 filtration Methods 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 9
- 238000009210 therapy by ultrasound Methods 0.000 claims description 9
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- 238000003756 stirring Methods 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 4
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 claims description 4
- 230000007935 neutral effect Effects 0.000 claims description 4
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 4
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 claims description 3
- PWGJDPKCLMLPJW-UHFFFAOYSA-N 1,8-diaminooctane Chemical compound NCCCCCCCCN PWGJDPKCLMLPJW-UHFFFAOYSA-N 0.000 claims description 3
- VLDPXPPHXDGHEW-UHFFFAOYSA-N 1-chloro-2-dichlorophosphoryloxybenzene Chemical compound ClC1=CC=CC=C1OP(Cl)(Cl)=O VLDPXPPHXDGHEW-UHFFFAOYSA-N 0.000 claims description 3
- BWAPJIHJXDYDPW-UHFFFAOYSA-N 2,5-dimethyl-p-phenylenediamine Chemical compound CC1=CC(N)=C(C)C=C1N BWAPJIHJXDYDPW-UHFFFAOYSA-N 0.000 claims description 3
- DCSSXQMBIGEQGN-UHFFFAOYSA-N 4,6-dimethylbenzene-1,3-diamine Chemical compound CC1=CC(C)=C(N)C=C1N DCSSXQMBIGEQGN-UHFFFAOYSA-N 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- WXNRYSGJLQFHBR-UHFFFAOYSA-N bis(2,4-dihydroxyphenyl)methanone Chemical compound OC1=CC(O)=CC=C1C(=O)C1=CC=C(O)C=C1O WXNRYSGJLQFHBR-UHFFFAOYSA-N 0.000 claims description 2
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- 125000006158 tetracarboxylic acid group Chemical group 0.000 claims description 2
- 239000004642 Polyimide Substances 0.000 description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 6
- 239000011159 matrix material Substances 0.000 description 5
- 239000011231 conductive filler Substances 0.000 description 4
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- 230000004913 activation Effects 0.000 description 1
- 150000004984 aromatic diamines Chemical class 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
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Abstract
The invention discloses a preparation method of a high-thermal-conductivity polyimide film, which comprises the following steps: s1, surface modification treatment of a first heat-conducting filler: s2, surface modification treatment of a second heat-conducting filler: s3, synthesis of polyamide acid slurry: s4, casting the polyamide acid slurry on a steel belt, drying to obtain a polyamide acid film, and S5, conveying the stretched polyamide acid film into an imidization heating box to perform imidization treatment to obtain the polyimide film.
Description
Technical Field
The invention belongs to the technical field of polyimide films, and particularly relates to a high-thermal-conductivity polyimide film. Meanwhile, the invention also relates to a high-thermal-conductivity polyimide film and a preparation method thereof.
Background
Polyimide film is one of the earliest products of polyimide, and is used for slot insulation of motors and cable wrapping materials. Thermoset polyimides, which have excellent thermal stability, chemical resistance and mechanical properties, are typically orange in color. The bending strength of the graphite or glass fiber reinforced polyimide can reach 345MPa, the bending modulus can reach 20GPa, the creep deformation of the thermosetting polyimide is small, and the thermosetting polyimide has higher tensile strength; the polyimide is chemically stable and does not require the addition of flame retardants to retard burning.
Through retrieval, the patent with the application number of 202111309974.4 discloses a preparation method of a polyimide film with high thermal conductivity and the polyimide film thereof, and relates to the field of polyimide film manufacture, the invention comprises the following steps of, under the protection of nitrogen, enabling the molar ratio of dianhydride to diamine to be 1:1, adding aromatic dianhydride into an aromatic diamine solution in batches for reaction to obtain a polyamic acid solution with the solid content of 10-20%; the invention forms a cellular high-efficiency three-dimensional heat conduction network structure with a compact framework, improves the heat conduction efficiency, simultaneously improves the toughness and the strength of the polyimide film, reduces the crack frequency, improves the quality of the polyimide film, and simultaneously casts the polyimide film onto a moving annular steel belt through the casting die head to obtain the polyimide film, thereby being beneficial to large-scale production and improving the production efficiency.
According to the scheme, the preparation process of the high-thermal-conductivity polyimide film is complicated, and the prepared high-thermal-conductivity polyimide film is poor in performance, low in insulating strength, and poor in thermal conductivity and thermal stability, so that the high-thermal-conductivity polyimide film and the preparation method thereof are provided.
Disclosure of Invention
The invention aims to solve the defects in the prior art, the preparation process of the high-thermal-conductivity polyimide film is simple and feasible, three thermal-conductive fillers of micron-grade boron nitride, submicron-grade alumina and nanometer-grade alumina are compounded, the surface of the polyimide film is modified, and the prepared polyamide acid film is stretched in the transverse direction and the longitudinal direction, so that the performance of the polyimide film is improved to a certain extent, and the insulation strength, the thermal conductivity and the thermal stability of the polyimide film are improved.
In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a high-thermal-conductivity polyimide film comprises the following steps:
s1, surface modification treatment of a first heat-conducting filler: adding micron-sized boron nitride into a sodium hydroxide solution for ultrasonic dispersion for 2 hours, standing at room temperature for 12 hours, filtering and washing until a washing solution is neutral, drying and crushing to obtain micron-sized boron nitride with activated surface, adding the activated boron nitride into dimethylacetamide for uniform dispersion, adding a silane coupling agent, and performing ultrasonic, filtering, washing and drying treatment to obtain surface-modified micron-sized boron nitride;
s2, surface modification treatment of a second heat-conducting filler: directly adding submicron-grade alumina and nanometer-grade alumina into dimethylacetamide to be uniformly dispersed, adding a silane coupling agent to be uniformly stirred, carrying out ultrasonic treatment for 2 hours, introducing nitrogen to carry out a protection reaction for 12 hours, washing with absolute ethyl alcohol, and drying and crushing to obtain surface-modified submicron-grade alumina and nanometer-grade alumina;
s3, synthesis of polyamide acid slurry: putting the modified first heat-conducting filler and the modified second heat-conducting filler into a container, adding dimethylacetamide into the container under the protection of nitrogen, performing ultrasonic treatment to obtain a dispersion liquid, adding diamine into the dispersion liquid, adding a small amount of dry dianhydride under the condition of stirring for multiple times, gradually increasing the solution viscosity, stopping adding dianhydride when the viscosity is increased to 200PaS, continuing stirring for 2 hours, filtering under the protection of dry nitrogen, and defoaming for later use;
s4, casting the polyamic acid slurry onto a steel belt, drying to obtain a polyamic acid film, and stripping the polyamic acid film to respectively perform stretching treatment to improve the performance of the film;
and S5, conveying the stretched polyamic acid film into an imidization heating box for imidization treatment to obtain the polyimide film.
Preferably, in S1, the first heat conductive filler is micron-sized boron nitride, the boron nitride is hexagonal boron nitride, the particle size of the micron-sized boron nitride is 2-4 μm, the weight of the micron-sized boron nitride is 5g, and the sodium hydroxide solution is 100g of 50% sodium hydroxide solution.
Preferably, in S2, the second thermally conductive filler is submicron alumina and nanometer alumina, the submicron alumina having a particle size of 0.3 to 0.5 μm, and the nanometer alumina having a particle size of 50 to 100nm.
Preferably, in S3, during the synthesis of the polyamic acid slurry, the reaction temperature is controlled to 10-20 ℃, the concentrations of diamine, dianhydride and dimethylacetamide are controlled to 15-25%, the purity is over 99.5%, the water content in the reaction vessel is less than 0.05%, and the molar ratio of diamine and dianhydride is 1.
Preferably, the diamine is any one or a mixture of two or more of p-phenylenediamine, 4, 6-dimethyl-m-phenylenediamine, 2, 5-dimethyl-p-phenylenediamine, 4-dimethylethylenediamine, 1, 8-octanediamine, 3-diamine diphenyl sulfide, and 2, 5-dimethylethylenediamine.
Preferably, the dianhydride is provided as any one or a mixture of two or more of bisphenol a type diether dianhydride, pyromellitic dianhydride, 3',4' -biphenyltetracarboxylic dianhydride, 3',4' -benzophenonetetracarboxylic dianhydride, and 2, 3',4' -diphenylethertetracarboxylic dianhydride.
Preferably, in S4, when the polyamic acid slurry is dried on the circulating steel belt, the temperature is high, which causes the polyamic acid slurry to separate from the steel belt, and low, which causes the polyamic acid slurry to adhere to the steel belt, and when the polyamic acid slurry is dried, the temperature is gradually increased from a low temperature to a high temperature, which is controlled at 130-210 ℃.
Preferably, in S4, the polyamic acid film obtained after peeling off from the steel strip is first fed to a longitudinal stretching machine, and then longitudinally stretched by heating to a stretching temperature by a preheating roll, and then fed to a transverse stretching machine, and then transversely stretched by heating to a stretching temperature by a preheating roll.
Preferably, in S5, after the polyamic acid film is sent into the imidization heating box, the temperature is quickly raised to 60 ℃ and maintained for 1h, then raised to 120 ℃ and maintained for 0.5h at the temperature raising speed of 10 ℃/min, then raised to 180 ℃ and maintained for 0.5h at the temperature raising speed of 10 ℃/min, then raised to 250 ℃ and maintained for 10min at the temperature raising speed of 10 ℃/min, then raised to 350 ℃ and maintained for 5min at the temperature raising speed of 20 ℃/min, finally raised to 440 ℃ and maintained for 3min at the temperature raising speed of 15 ℃/min, and after cooling, the high-thermal conductivity polyimide film can be prepared.
The invention also provides a high-thermal-conductivity polyimide film which is prepared according to the preparation method of the high-thermal-conductivity polyimide film.
The invention has the technical effects and advantages that: compared with the prior art, the high-thermal-conductivity polyimide film and the preparation method thereof have the advantages that the preparation process is simple and feasible, three thermal-conductivity fillers of micron-sized boron nitride, submicron-sized alumina and nanoscale alumina are compounded, the surface of the polyimide film is modified, the prepared polyamic acid film is stretched in the transverse direction and the longitudinal direction, the performance of the polyimide film is improved to a certain extent, and the insulation strength, the thermal conductivity and the thermal stability of the polyimide film are improved.
Drawings
FIG. 1 is a flow chart of the method of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Referring to fig. 1, the present invention provides a method for preparing a polyimide film with high thermal conductivity, including the following steps:
s1, surface modification treatment of a first heat-conducting filler: adding micron-sized boron nitride into a sodium hydroxide solution for ultrasonic dispersion for 2 hours, standing at room temperature for 12 hours, filtering and washing until a washing solution is neutral, drying and crushing to obtain surface-activated micron-sized boron nitride, adding the activated boron nitride into dimethylacetamide for uniform dispersion, adding a silane coupling agent, and performing ultrasonic, filtering, washing and drying treatment to obtain surface-modified micron-sized boron nitride;
s2, surface modification treatment of a second heat-conducting filler: directly adding submicron-grade alumina and nanometer-grade alumina into dimethyl acetamide to be uniformly dispersed, adding a silane coupling agent to be uniformly stirred, carrying out ultrasonic treatment for 2 hours, introducing nitrogen to carry out a protection reaction for 12 hours, washing with absolute ethyl alcohol, drying and crushing to obtain surface-modified submicron-grade alumina and nanometer-grade alumina;
the surface of the alumina contains more hydroxyl groups, and surface activation treatment is not needed. The microstructure of the submicron alumina is spherical, and the thermal conductivity of the submicron alumina is 30W/m.K.
S3, synthesis of polyamide acid slurry: putting the modified first heat-conducting filler and the modified second heat-conducting filler into a container, adding dimethylacetamide into the container under the protection of nitrogen, performing ultrasonic treatment to obtain a dispersion liquid, adding diamine into the dispersion liquid, adding a small amount of dry dianhydride under the condition of stirring for multiple times, gradually increasing the solution viscosity, stopping adding dianhydride when the viscosity is increased to 200PaS, continuing stirring for 2 hours, filtering under the protection of dry nitrogen, and defoaming for later use;
when the polyamic acid slurry is prepared, factors such as temperature, raw material feeding sequence, raw material proportion and the like can generate great influence on the performance of polyamic acid;
s4, casting the polyamic acid slurry onto a steel belt, drying to obtain a polyamic acid film, and stripping the polyamic acid film to respectively perform stretching treatment to improve the performance of the film;
the steel belt is a circulating steel belt made of stainless steel, and the obtained polyamide acid film is in a gel state; the running speed of the steel strip can be controlled according to the product variety and the yield.
And S5, conveying the stretched polyamic acid film into an imidization heating box for imidization treatment to obtain the polyimide film.
The thermal conductivity of subminiature-and nanoscale aluminas increases gradually with increasing amounts of thermally conductive fillers, with increasing thermal conductivity at 40% to 50% being most pronounced because the microstructure of the alumina particles is spherical, they are distributed uniformly in the polymer matrix, and orientation has little effect on them, and the thermal conductivity can only be increased by increasing the amount of filler. When the filling amount of the matrix is less, the possibility that the alumina particles are mutually connected in the film is lower, heat needs to be conducted through a phase interface of the polymer matrix and the alumina, the thermal resistance is high, the conduction efficiency is low, and the heat conductivity coefficient is low; when the content of the aluminum oxide is more than 40%, a large number of aluminum oxide particles are directly connected in the film matrix to form a complete heat conduction path, so that the interface thermal resistance is greatly reduced, and the heat conductivity coefficient is improved.
The modified nanoscale alumina is tightly combined with the polymer object, and the modified nanoscale alumina serves as a part of physical cross-linking points, so that the tensile strength of the film is further improved.
The micron-sized boron nitride can not form a complete heat conduction path, so that the heat conductivity in the vertical direction is low, after the submicron-sized aluminum oxide and the nanometer-sized aluminum oxide are added, due to the spherical microstructure, the orientation degree is small, the micron-sized boron nitride can be uniformly distributed in a polymer matrix, a bridge effect is formed among particles of the micron-sized boron nitride, and due to the addition of the submicron-sized aluminum oxide and the nanometer-sized aluminum oxide, gaps among large particles are filled, the heat conduction path is denser, and the heat conduction capability is improved.
In S1, the first heat-conducting filler is micron-sized boron nitride, the boron nitride is hexagonal boron nitride, the particle size of the micron-sized boron nitride is 2-4 microns, the weight of the micron-sized boron nitride is 5g, and the sodium hydroxide solution is 100g of 50% sodium hydroxide solution.
In S2, the second heat conducting filler is submicron alumina and nanometer alumina, the particle size of the submicron alumina is 0.3-0.5 μm, and the particle size of the nanometer alumina is 50-100nm.
In S3, in the synthesis process of the polyamide acid slurry, the reaction temperature is controlled to be 10-20 ℃, the concentrations of diamine, dianhydride and dimethylacetamide are controlled to be 15-25%, the purity is over 99.5%, the water content in a reaction vessel is less than 0.05%, and the molar ratio of diamine to dianhydride is 1.
The diamine is any one or mixture of more than two of p-phenylenediamine, 4, 6-dimethyl-m-phenylenediamine, 2, 5-dimethyl-p-phenylenediamine, 4-dimethylethylenediamine, 1, 8-octanediamine, 3-diamine diphenyl sulfide and 2, 5-dimethylethylenediamine.
The dianhydride is any one or a mixture of more than two of bisphenol A type diether dianhydride, pyromellitic dianhydride, 3',4' -biphenyl tetracarboxylic dianhydride, 3',4' -benzophenone tetracarboxylic dianhydride and 2, 3',4' -diphenyl ether tetracarboxylic dianhydride.
In S4, when the polyamic acid slurry is dried on a circulating steel belt, the polyamic acid slurry can be separated from the steel belt due to high temperature, the polyamic acid slurry can be adhered to the steel belt due to low temperature, and the temperature of the polyamic acid slurry is gradually increased from low temperature to high temperature when the polyamic acid slurry is dried, wherein the temperature is controlled to be 130-210 ℃.
In S4, the prepared polyamic acid film is stripped from the steel belt, and then enters a longitudinal stretcher, is heated to the stretching temperature by a preheating roller to be longitudinally stretched, and then enters a transverse stretcher after reaching the longitudinal stretching ratio, and is heated to the stretching temperature by the preheating roller to be transversely stretched, so that the performance of the polyamic acid film is improved.
In S5, after the polyamic acid film is sent into an imidization heating box, the temperature is quickly raised to 60 ℃ and maintained for 1h, then raised to 120 ℃ and maintained for 0.5h at the heating rate of 10 ℃/min, then raised to 180 ℃ and maintained for 0.5h at the heating rate of 10 ℃/min, then raised to 250 ℃ and maintained for 10min at the heating rate of 10 ℃/min, then raised to 350 ℃ and maintained for 5min at the heating rate of 20 ℃/min, finally raised to 440 ℃ and maintained for 3min at the heating rate of 15 ℃/min, and after cooling, the high-thermal conductivity polyimide film can be prepared.
The invention also provides a high-thermal-conductivity polyimide film which is prepared according to the preparation method of the high-thermal-conductivity polyimide film.
In summary, the following steps: when the surface-modified micron-sized boron nitride is used, micron-sized boron nitride is added into a sodium hydroxide solution for ultrasonic dispersion for 2 hours, then the mixture is placed at room temperature for 12 hours, filtered and washed until a washing liquid is neutral, dried and crushed to obtain micron-sized boron nitride with activated surface, the activated boron nitride is added into dimethylacetamide for uniform dispersion, and the silane coupling agent is added for ultrasonic treatment, filtering, washing and drying to obtain the surface-modified micron-sized boron nitride; directly adding the submicron-grade alumina and the nanometer-grade alumina into dimethylacetamide to be uniformly dispersed, adding a silane coupling agent to be uniformly stirred, carrying out ultrasonic treatment for 2 hours, introducing nitrogen to carry out a protection reaction for 12 hours, washing with absolute ethyl alcohol, and drying and crushing to obtain surface-modified submicron-grade alumina and nanometer-grade alumina;
then putting the modified first heat-conducting filler and the modified second heat-conducting filler into a container, adding dimethylacetamide into the container under the protection of nitrogen, carrying out ultrasonic treatment to obtain a dispersion liquid, adding diamine into the dispersion liquid, then adding a small amount of dry dianhydride under the condition of stirring for many times, gradually increasing the solution viscosity, stopping adding dianhydride when the viscosity is increased to 200PaS, continuing stirring for 2 hours, filtering under the protection of dry nitrogen, and defoaming for later use;
finally, casting the polyamic acid slurry on a steel belt, drying to obtain a polyamic acid film, and stripping the polyamic acid film to respectively perform stretching treatment to improve the performance of the film; and (3) conveying the stretched polyamide acid film into an imidization heating box for imidization treatment to obtain the polyimide film.
The preparation process of the high-thermal-conductivity polyimide film is simple and feasible, three thermal-conductivity fillers of micron-grade boron nitride, submicron-grade alumina and nanometer-grade alumina are compounded, the surface of the polyimide film is modified, and the prepared polyamide acid film is stretched in the transverse direction and the longitudinal direction, so that the performance of the polyimide film is improved to a certain extent, and the insulating strength, the thermal conductivity and the thermal stability of the polyimide film are improved.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.
Claims (10)
1. A preparation method of a high-thermal-conductivity polyimide film is characterized by comprising the following steps: the method comprises the following steps:
s1, surface modification treatment of a first heat-conducting filler: adding micron-sized boron nitride into a sodium hydroxide solution for ultrasonic dispersion for 2 hours, standing at room temperature for 12 hours, filtering and washing until a washing solution is neutral, drying and crushing to obtain micron-sized boron nitride with activated surface, adding the activated boron nitride into dimethylacetamide for uniform dispersion, adding a silane coupling agent, and performing ultrasonic, filtering, washing and drying treatment to obtain surface-modified micron-sized boron nitride;
s2, surface modification treatment of a second heat-conducting filler: directly adding submicron-grade alumina and nanometer-grade alumina into dimethyl acetamide to be uniformly dispersed, adding a silane coupling agent to be uniformly stirred, carrying out ultrasonic treatment for 2 hours, introducing nitrogen to carry out a protection reaction for 12 hours, washing with absolute ethyl alcohol, drying and crushing to obtain surface-modified submicron-grade alumina and nanometer-grade alumina;
s3, synthesis of polyamide acid slurry: putting the modified first heat-conducting filler and the modified second heat-conducting filler into a container, adding dimethylacetamide into the container under the protection of nitrogen, performing ultrasonic treatment to obtain a dispersion liquid, adding diamine into the dispersion liquid, then adding a small amount of dry dianhydride under the condition of stirring for multiple times, gradually increasing the viscosity of the solution, stopping adding dianhydride when the viscosity is increased to 200PaS, continuing stirring for 2 hours, filtering under the protection of dry nitrogen, and defoaming for later use;
s4, casting the polyamic acid slurry onto a steel belt, drying to obtain a polyamic acid film, and stripping the polyamic acid film to respectively perform stretching treatment to improve the performance of the film;
and S5, conveying the stretched polyamic acid film into an imidization heating box for imidization treatment to obtain the polyimide film.
2. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S1, the first heat-conducting filler is micron-sized boron nitride, the boron nitride is hexagonal boron nitride, the particle size of the micron-sized boron nitride is 2-4 microns, the weight of the micron-sized boron nitride is 5g, and the sodium hydroxide solution is 100g of 50% sodium hydroxide solution.
3. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S2, the second heat-conducting filler is submicron alumina and nanometer alumina, the particle size of the submicron alumina is 0.3-0.5 μm, and the particle size of the nanometer alumina is 50-100nm.
4. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S3, in the synthesis process of the polyamide acid slurry, the reaction temperature is controlled to be 10-20 ℃, the concentrations of diamine, dianhydride and dimethylacetamide are controlled to be 15-25%, the purity is over 99.5%, the water content in a reaction vessel is less than 0.05%, and the molar ratio of diamine to dianhydride is 1.
5. The preparation method of the polyimide film with high thermal conductivity according to claim 1, wherein the preparation method comprises the following steps: the diamine is any one or mixture of more than two of p-phenylenediamine, 4, 6-dimethyl-m-phenylenediamine, 2, 5-dimethyl-p-phenylenediamine, 4-dimethylethylenediamine, 1, 8-octanediamine, 3-diamine diphenyl sulfide and 2, 5-dimethylethylenediamine.
6. The preparation method of the polyimide film with high thermal conductivity as claimed in claim 1, wherein the preparation method comprises the following steps: the dianhydride is any one or a mixture of more than two of bisphenol A type diether dianhydride, pyromellitic dianhydride, 3',4' -biphenyl tetracarboxylic dianhydride, 3',4' -benzophenone tetracarboxylic dianhydride and 2, 3',4' -diphenyl ether tetracarboxylic dianhydride.
7. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S4, when the polyamic acid slurry is dried on a circulating steel belt, the polyamic acid slurry can be separated from the steel belt due to high temperature, the polyamic acid slurry can be adhered to the steel belt due to low temperature, and the temperature of the polyamic acid slurry is gradually increased from low temperature to high temperature during drying, wherein the temperature is controlled to be 130-210 ℃.
8. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S4, the prepared polyamic acid film is stripped from the steel belt, enters a longitudinal stretcher firstly, is heated to the stretching temperature by a preheating roller to be longitudinally stretched, reaches the longitudinal stretching ratio, enters a transverse stretcher, and is heated to the stretching temperature by the preheating roller to be transversely stretched.
9. The method for preparing a polyimide film with high thermal conductivity according to claim 1, wherein the method comprises the following steps: in S5, after the polyamic acid film is sent into an imidization heating box, the temperature is quickly raised to 60 ℃ and maintained for 1h, then raised to 120 ℃ and maintained for 0.5h at the heating rate of 10 ℃/min, then raised to 180 ℃ and maintained for 0.5h at the heating rate of 10 ℃/min, then raised to 250 ℃ and maintained for 10min at the heating rate of 10 ℃/min, then raised to 350 ℃ and maintained for 5min at the heating rate of 20 ℃/min, finally raised to 440 ℃ and maintained for 3min at the heating rate of 15 ℃/min, and after cooling, the high-thermal conductivity polyimide film can be prepared.
10. A high heat conduction polyimide film is characterized in that: the method for preparing a highly thermally conductive polyimide film according to any one of claims 1 to 9.
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| CN117430848A (en) * | 2023-12-20 | 2024-01-23 | 山东德钧智能科技服务有限公司 | Heat-conducting polyimide film added with inorganic auxiliary agent and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117430848A (en) * | 2023-12-20 | 2024-01-23 | 山东德钧智能科技服务有限公司 | Heat-conducting polyimide film added with inorganic auxiliary agent and preparation method and application thereof |
| CN117430848B (en) * | 2023-12-20 | 2024-02-20 | 山东德钧智能科技服务有限公司 | Heat-conducting polyimide film added with inorganic auxiliary agent and preparation method and application thereof |
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