CN113248773A - Polyimide porous membrane and preparation method thereof - Google Patents

Polyimide porous membrane and preparation method thereof Download PDF

Info

Publication number
CN113248773A
CN113248773A CN202110533302.5A CN202110533302A CN113248773A CN 113248773 A CN113248773 A CN 113248773A CN 202110533302 A CN202110533302 A CN 202110533302A CN 113248773 A CN113248773 A CN 113248773A
Authority
CN
China
Prior art keywords
porous membrane
polyimide porous
polyamic acid
producing
glass plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202110533302.5A
Other languages
Chinese (zh)
Other versions
CN113248773B (en
Inventor
程跃
高琦
吕凯
邱长泉
虞少波
蔡裕宏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Ruiji New Material Technology Co ltd
Original Assignee
Shanghai Ruiji New Material Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Ruiji New Material Technology Co ltd filed Critical Shanghai Ruiji New Material Technology Co ltd
Priority to CN202110533302.5A priority Critical patent/CN113248773B/en
Publication of CN113248773A publication Critical patent/CN113248773A/en
Priority to PCT/CN2022/092540 priority patent/WO2022242547A1/en
Application granted granted Critical
Publication of CN113248773B publication Critical patent/CN113248773B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/26—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/08—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/044—Elimination of an inorganic solid phase
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2201/00—Foams characterised by the foaming process
    • C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
    • C08J2201/044—Elimination of an inorganic solid phase
    • C08J2201/0442—Elimination of an inorganic solid phase the inorganic phase being a metal, its oxide or hydroxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2203/00—Foams characterized by the expanding agent
    • C08J2203/02—CO2-releasing, e.g. NaHCO3 and citric acid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
    • C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention relates to the technical field of preparation of polymer dielectric materials, and discloses a preparation method of a polyimide porous membrane. By the special method, the high-performance polyimide porous membrane with low dielectric constant, uniform pore distribution, good thermal stability and good size stability is obtained, so that the signal transmission speed can be increased, signal interference and inductive coupling are reduced, and the polyimide porous membrane is better applied to the integrated circuit industry.

Description

Polyimide porous membrane and preparation method thereof
Technical Field
The invention relates to the technical field of preparation of polymer dielectric materials, in particular to a polyimide porous membrane and a preparation method thereof.
Background
With the development of scientific technology, the trend of the integrated circuit industry towards low-dimensional, large-scale and even ultra-large-scale integration is increasingly obvious. In order to increase the signal transmission speed and reduce signal interference and inductive coupling, a material with a low dielectric constant must be used. For the next generation of dielectric materials, a dielectric constant of 2.2 or less is required. Polyimide is the most promising polymer dielectric material due to its outstanding thermal and mechanical properties. Because the dielectric constant of common polyimide is usually between 3 and 4, the synthesis of polyimide materials with lower dielectric constant has become a hot spot of current research.
The dielectric constant of a material is closely related to its molar polarizability and molar volume according to the Clausius Mossotti equation. Therefore, there are two main types of methods for reducing the PI dielectric constant: (1) substituents with low polarizability are introduced to reduce the polarizability of dipoles in the molecule. (2) The number of dipoles in a unit volume is reduced by introducing bulky groups or even pore structures inside the material.
The dielectric constant of a common polyimide film is 3-4, and the common polyimide film cannot meet the requirements of integrated circuits at the present stage, while the traditional polyimide porous film has a lower dielectric constant, but the pore distribution is not uniform, the thermal stability is poor, and the dimensional stability is poor.
The Clausius Mossotti equation is as follows:
Figure BDA0003068731840000021
wherein Pm is the molar polarizability of the atomic group, and Vm is the molar volume of the atomic group.
Disclosure of Invention
In view of the above, the present invention is to provide a method for preparing a polyimide porous membrane, which has a low dielectric constant, uniform pore distribution, good thermal stability, and good dimensional stability.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the invention aims to provide a preparation method of a polyimide porous membrane, which comprises the following steps: dissolving two different aromatic diisocyanates in a polar solvent, adding aromatic dianhydride, fully stirring to obtain an intermediate product polyamic acid, defoaming the polyamic acid, coating the polyamic acid on a glass plate, and performing heat treatment to obtain the polyimide porous membrane.
Further, after the intermediate product polyamic acid is obtained, a pore-forming agent is added to be uniformly mixed, the mixture is defoamed and coated on a glass plate, then heat treatment is carried out, and finally the pore-forming agent is removed to obtain the polyimide porous membrane.
Further, the aromatic diisocyanate is selected from one of 4-methyl-m-phenylene diisocyanate, 2, 6-toluene diisocyanate, 4' -methylene bis (phenyl isocyanate), 2,4, 6-trimethyl-1, 3-benzene diisocyanate or 2,3,5, 6-tetramethyl-1, 4-benzene diisocyanate;
further, the aromatic dianhydride is selected from one of 3,4,3 ', 4' -benzophenone tetracarboxylic dianhydride, 1,2,4, 5-pyromellitic dianhydride, and 3,4,3 ', 4' -biphenyl tetracarboxylic dianhydride.
Further, the polar solvent is selected from one or more of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
Further, the pore former is selected from SiO2One or more of ceramic, aluminum powder and magnesium powder.
Further, the copolymerization reaction conditions of the two different aromatic diisocyanates and the aromatic dianhydride are under the protection of nitrogen and at the temperature of 0-40 ℃.
Further, two different aromatic diisocyanates and aromatic dianhydride are fully stirred to obtain an intermediate product polyamic acid, and the solid content of the polyamic acid is 13-16 wt%.
Further, the solid content of the polyamic acid was 15 wt%.
Further, the heat treatment adopts step heating, and the step heating process is as follows: heating to 100 deg.C, maintaining for 30min, heating to 110 deg.C, maintaining for 30min, heating to 120 deg.C, maintaining for 60min, heating to 140 deg.C, and maintaining for 60 min.
Further, the two different aromatic diisocyanates are 4, 4' -methylenebis (phenyl isocyanate) and 4-methyl-m-phenylene diisocyanate;
still further, the aromatic dianhydride is 1,2,4, 5-benzenetetracarboxylic dianhydride.
Specifically, the molar ratio of the sum of the molar amounts of the 4, 4' -methylenebis (phenyl isocyanate) and the 4-methyl-m-phenylene diisocyanate to the 1,2,4, 5-pyromellitic dianhydride is 1:1 during the feeding reaction.
Preferably, the charged molar amount of the 4, 4' -methylenebis (phenyl isocyanate) is less than the charged molar amount of 4-methyl-m-phenylene diisocyanate.
More preferably, the molar ratio of 4, 4' -methylenebis (phenyl isocyanate) to 4-methyl-m-phenylene diisocyanate is 1: 4.
Further, the pore-forming agent is SiO2Said SiO2Is nano-scale SiO2。
In particular, the nano-scale SiO2The average particle diameter of (B) is 5 to 45 nm.
Preferably, the nano-SiO is2Has an average particle diameter of 30 nm.
Further, a reactive ion etching method is used to remove the porogen.
Further, a hydrofluoric/ammonium fluoride buffer was used to remove the porogen.
The present invention also provides a polyimide porous film produced by any of the above-mentioned methods.
Further, the polyimide porous film has a dielectric constant of 1.45 to 1.98.
Further, the polyimide porous film has a dielectric constant of 1.45 to 1.74.
Preferably, the polyimide porous film has a dielectric constant of 1.45 to 1.63, more preferably 1.45 to 1.60, and most preferably 1.45 to 1.49.
Further, the polyimide porous membrane has a porosity of 68 to 79%.
Further, the polyimide porous membrane has a porosity of 73 to 79%.
Further, the polyimide porous membrane has a thermal shrinkage of 0.25 to 0.28% in the MD direction and a thermal shrinkage of 0.25 to 0.30% in the TD direction at 150 ℃.
The invention has the following beneficial effects:
the invention provides a preparation method of a polyimide porous membrane, which generates CO by adopting polycondensation reaction of two different aromatic diisocyanates and aromatic dianhydride2Is beneficial to the formation of pores, and simultaneously nano SiO is added2The pore-forming agent is more beneficial to the formation of pores, ensures that the formed pores are more uniform, and has higher porosity, thereby obtaining the high-performance polyimide porous membrane with low dielectric constant, uniform pore distribution, good thermal stability and good size stability.
Drawings
FIG. 1 shows the chemical reaction formulas of 4, 4' -methylenebis (phenyl isocyanate), 4-methyl-m-phenylene diisocyanate and 1,2,4, 5-pyromellitic dianhydride in 11 embodiments of the present invention.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The specific embodiment of the invention provides a preparation method of a polyimide porous membrane, which has the technical key points that: under the protection of nitrogen and at a certain temperature, 4' -methylene bis (phenyl isocyanate) and 4-methyl-m-phenylene diisocyanate are dissolved in a polar solvent, 1,2,4, 5-benzene tetracarboxylic dianhydride is added to be stirred and reacted to obtain intermediate product polyamic acid, the obtained polyamic acid is added with a pore-forming agent to be uniformly mixed, the mixture is defoamed in vacuum and then coated on a glass plate, thermal imidization treatment is carried out, and then the pore-forming agent is removed, so that the polyimide porous membrane is obtained.
The polar solvent is one or more selected from N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
Here, the pore former is selected from SiO2One or more of ceramic, aluminum powder and magnesium powder.
Preferably, the pore-forming agent is SiO2Said SiO2Is nano-scale SiO2. Due to the nano-SiO2The porous structure can adsorb metal ions, so that the possibility of oxidation and yellowing is reduced; second nano-scale SiO2The pore-forming agent has larger bulk density, is easier to mix with resin and is more beneficial to operation.
Further preferred is nanoscale SiO2The average particle diameter of (2) is 5 to 45nm, wherein an excessively small particle diameter is not favorable for pore formation, and an excessively large particle diameter is favorable for film strength, and more preferably an average particle diameter of 30 nm.
Here, the copolymerization reaction temperature of 4, 4' -methylenebis (phenyl isocyanate), 4-methyl-m-phenylene diisocyanate and 1,2,4, 5-pyromellitic dianhydride is 0 to 40 ℃, and a water bath at 25 ℃ is preferable.
Here, the solid content of the polyamic acid is between 13 and 16 wt%.
Preferably, the solid content of the polyamic acid is 15 wt%.
Here, the heat treatment employs a step heating process, and the step heating process is: firstly heating to 100 ℃ and preserving heat for 30min, then heating to 110 ℃ and preserving heat for 30min, then heating to 120 ℃ and preserving heat for 60min, then heating to 140 ℃ and preserving heat for 60min, and adopting step heating only for reaction, and having no obvious influence on dielectric constant.
Here, the molar ratio of the sum of the molar amounts of 4, 4' -methylenebis (phenylisocyanate) and 4-methyl-m-phenylene diisocyanate to 1,2,4, 5-pyromellitic dianhydride in the charging reaction was 1: 1.
Preferably, the molar ratio of the 4, 4' -methylene bis (phenyl isocyanate) to the 4-methyl-m-phenylene diisocyanate is 2-8: 2-8;
more preferably, the charged molar amount of the 4, 4' -methylenebis (phenyl isocyanate) is not more than the charged molar amount of 4-methyl-m-phenylene diisocyanate.
Still more preferably, the molar ratio of 4, 4' -methylenebis (phenyl isocyanate) to 4-methyl-m-phenylene diisocyanate is 1:1, 2:3, 1:4, most preferably 1: 4.
Here, a reactive ion etching method is used to remove the porogen. When the method is adopted, the fluorine-containing gas generates free F, free F and SiO under plasma2Reaction to form SiF4And oxygen.
Here, a hydrofluoric acid/ammonium fluoride buffer is used to remove the porogen. When the method is adopted, the fluorine-containing substance and SiO2Reaction to form SiF4And oxygen.
Here, the coating film thickness is 100 to 500 μm.
The thickness of the polyimide porous membrane is 8 to 40 μm.
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples, the performance parameters were determined as follows:
(1) porosity of the material
Determining the pore volume V of the membrane by adopting an immersion method according to the mass change before and after the membrane is immersed in waterHole(s)Skeleton volume V of the filmMembrane skeletonCan be obtained by the density of the membrane raw material and the quality of a dry membrane, and has the porosity of VHole(s)/(VHole(s)+VMembrane skeleton)；
(2) Dielectric constant
The dielectric constant of the film was determined by using an Agilent 4284A capacitance meter equipped with an Agilent 16451B dielectric connector, and the dielectric constant was obtained by calculation after measuring the capacitance of the film, and the frequency was 1 MHz.
(3) Dimensional stability
One film sheet with a drawing direction (MD) of 280mm and a Transverse Direction (TD) of 255mm is cut, and circular holes with the diameter of 1mm are punched at the positions, 13mm away from the edge, of four corners of the film. The samples were placed at 23 ℃ at 50% relative humidity for at least 24h, the distances A-B, C-D, A-C, B-D between the centers of the wells were measured, the samples were then placed in a 150 ℃ incubator without tension for 30min, taken out at 23 ℃ at 50% relative humidity for 3h, and the distances between the wells were measured. The linear dimensional changes in each direction are as follows:
Figure BDA0003068731840000071
Figure BDA0003068731840000072
(4) in table Tg/(℃)、T5％/(℃)
Glass transition temperature TgMeasurement by Thermomechanical Method (TMA)
T5％Measured according to GBT27761-2011
Example 1
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, coating with a film thickness of 300 μm, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with a thickness of 18 +/-1 μm, placing the obtained film in a reactive ion etcher for etching (using helium as protective gas and CHF3 as etching gas), and performing etchingFor 1h, removing SiO in the polyimide film2Pore-forming agent to obtain the porous polyimide film.
Example 2
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate with an automatic coating machine, coating with a thickness of 300 μm, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with a thickness of 18 +/-1 μm, placing the obtained film in a buffer solution of hydrofluoric acid/ammonium fluoride (volume ratio of 3:5), soaking for 30min, and removing SiO in the polyimide film2And obtaining the porous polyimide film.
Example 3
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 5nm2(0.05 gSiO per 100g polyamic acid2) Mixing, defoaming, coating on clean glass plate with a coating thickness of 300 μm by an automatic coating machine, placing the glass plate in an oxygen-free oven, and heating to 1 deg.C by stepsKeeping the temperature at 00 ℃ for 30min, then heating to 110 ℃ for 30min, then heating to 120 ℃ for 60min, then heating to 140 ℃ for 60min) for heat treatment to form polyimide, taking out the glass plate after cooling to room temperature, putting the glass plate into boiling water to separate the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, putting the obtained film into a reactive ion etcher for etching (helium is used as protective gas, CHF3 is used as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 4
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 45nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (taking helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 5
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Defoaming the obtained polyamic acid solution, coating the polyamic acid solution on a clean glass plate by an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating (heating to 100 ℃ and preserving heat for 30min, then heating to 110 ℃ and preserving heat for 30min, then heating to 120 ℃ and preserving heat for 60min, and then heating to 140 ℃ and preserving heat for 60min) to form polyimide, taking out the glass plate after cooling to room temperature, and placing the glass plate in boiling water to separate the polyimide film from the glass plate to obtain the porous imide film with the thickness of 18 +/-1 mu m.
Example 6
(1) 0.05mol (8.71g) of 4-methyl-m-phenylene diisocyanate and 0.05mol (12.51g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 243.84g of NMP under nitrogen protection at 25 ℃ and 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (taking helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 7
(1) 0.02mol (3.48g) of 4-methyl-m-phenylene diisocyanate and 0.08mol (20.02g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 256.76g of NMP under nitrogen protection at 25 ℃ and 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (taking helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 8
(1) 0.03mol (5.22g) of 4-methyl-m-phenylene diisocyanate and 0.07mol (17.52g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 252.45g of NMP under nitrogen protection at 25 ℃ and 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Defoaming after mixing uniformly, coating on a clean glass plate with an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, taking out the glass plate and placing the glass plate in boiling water after cooling to the room temperature, so that the polyimide film and the glass plate are coated on the clean glass plate with an automatic coating machine, wherein the polyimide film is formed by heating the glass plate to 120 ℃ and keeping the temperature for 60min, and then cooling to the room temperatureSeparating to obtain 18 + -1 μm thick imide film, etching in reactive ion etcher (with helium as protective gas and CHF3 as etching gas) for 1 hr, and removing SiO in the polyimide film2Pore-forming agent to obtain the porous polyimide film.
Example 9
(1) 0.04mol (6.97g) of 4-methyl-m-phenylene diisocyanate and 0.06mol (15.01g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 248.14g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (taking helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 10
(1) 0.06mol (10.45g) of 4-methyl-m-phenylene diisocyanate and 0.04mol (10.01g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 239.53g of NMP under nitrogen protection at 25 ℃ and 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(Per 100g of polyAmic acid plus 0.05gSiO2) Mixing uniformly, defoaming, coating on a clean glass plate by using an automatic coating machine, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating process (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (taking helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Example 11
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Defoaming after mixing uniformly, coating on a clean glass plate with an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, keeping the temperature at 120 ℃ for 2h, performing heat treatment to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etching machine for etching (with helium as protective gas and CHF3 as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Comparative example 1
(1) 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was dissolved in a three-necked flask containing 237.04g of NMP under nitrogen protection at 25 ℃ and reacted with stirring for 5 hours by adding 0.1mol (20.02g) of 1-aminooctadecane to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) And defoaming the obtained polyamic acid solution, coating the polyamic acid solution on a clean glass plate by using an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oven, heating to 175 ℃ at the speed of 1 ℃/min, preserving the temperature for 30min, and removing a solvent DMF. Cooling to room temperature, placing in an oxygen-free oven, performing thermal imidization to form polyimide by using step heating (heating to 200 ℃ and keeping the temperature for 30min, then heating to 280 ℃ and keeping the temperature for 10min, then heating to 320 ℃ and keeping the temperature for 5min, then heating to 370 ℃ and keeping the temperature for 3min, and finally heating to 400 ℃ and keeping the temperature for 1min), cooling to room temperature, taking out the glass plate, placing in boiling water, and separating the polyimide film from the glass plate to obtain the polyimide film with the thickness of 18 +/-1 mu m.
Comparative example 2
(1) 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was dissolved in a three-necked flask containing 237.04g of NMP under nitrogen protection at 25 ℃ and 0.1mol (10.81g) of 1, 4-phenylenediamine was charged and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) Defoaming after mixing uniformly, coating on a clean glass plate with an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment at 130 ℃ to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, separating the polyimide film from the glass plate to obtain an imide film with the thickness of 18 +/-1 mu m, placing the obtained film in a reactive ion etcher for etching (helium is used as protective gas, CHF3 is used as etching gas), and removing SiO in the polyimide film for 1h2Pore-forming agent to obtain the porous polyimide film.
Comparative example 3
(1) 0.08mol (13.93g) of 4-methyl-m-phenylene diisocyanate and 0.02mol (5g) of 4, 4' -methylenebis (phenyl isocyanate) were dissolved in a three-necked flask containing 230.86g of NMP under nitrogen protection at 25 ℃, 0.1mol (21.81g) of 1,2,4, 5-benzenetetracarboxylic dianhydride was added thereto and stirred for 5 hours to obtain an intermediate polyamic acid solution having a solid content of 15%.
(2) Adding the obtained polyamic acid solution into nano SiO with the average grain diameter of 30nm2(0.05 gSiO per 100g polyamic acid2) The preparation method comprises the following steps of mixing uniformly, defoaming, coating the mixture on a clean glass plate by an automatic coating machine after defoaming, wherein the coating thickness is 300 mu m, placing the glass plate in an oxygen-free oven, performing heat treatment by using a step heating (heating to 100 ℃ and keeping the temperature for 30min, then heating to 110 ℃ and keeping the temperature for 30min, then heating to 120 ℃ and keeping the temperature for 60min, and then heating to 140 ℃ and keeping the temperature for 60min) to form polyimide, cooling to room temperature, taking out the glass plate, placing the glass plate in boiling water, and separating the polyimide film from the glass plate to obtain the imide film with the thickness of 18 +/-1 mu m.
TABLE 1 comparison of the Properties of polyimide films prepared in examples 1 to 11 and comparative examples 1 to 3
Figure BDA0003068731840000171
It can be seen that the molar ratio of 4-methyl-m-phenylene diisocyanate, 4' -methylenebis (phenyl isocyanate), 1,2,4, 5-benzenetetracarboxylic dianhydride was 80: 20: 100, adding SiO with average grain diameter of 30nm2(100g Polyamic acid plus 0.05gSiO2) The porous polyimide film obtained by etching by adopting the reactive ion etcher has better thermal stability and dimensional stability, higher porosity and lower dielectric constant.
The above matters related to the common general knowledge are not described in detail and can be understood by those skilled in the art.
The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims (13)

1. A method for preparing a polyimide porous membrane is characterized by comprising the following steps: dissolving two different aromatic diisocyanates in a solvent, adding aromatic dianhydride, stirring to obtain an intermediate polyamic acid, defoaming and coating the polyamic acid, and then carrying out heat treatment to obtain the polyimide porous membrane.
2. The method for producing a polyimide porous membrane according to claim 1, characterized in that: and after the intermediate product polyamic acid is obtained, adding a pore-forming agent for mixing, defoaming and coating, performing heat treatment, and finally removing the pore-forming agent to obtain the polyimide porous membrane.
3. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: the aromatic diisocyanate is selected from one of 4-methyl-m-phenylene diisocyanate, 2, 6-toluene diisocyanate, 4' -methylene bis (phenyl isocyanate), 2,4, 6-trimethyl-1, 3-benzene diisocyanate or 2,3,5, 6-tetramethyl-1, 4-benzene diisocyanate; the aromatic dianhydride is selected from one of 3,4,3 ', 4' -benzophenone tetracarboxylic dianhydride, 1,2,4, 5-pyromellitic dianhydride and 3,4,3 ', 4' -biphenyl tetracarboxylic dianhydride.
4. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: the solvent is one or more selected from N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
5. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: the pore former is selected from SiO2One or more of ceramic, aluminum powder and magnesium powder.
6. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: the copolymerization reaction conditions of the two different aromatic diisocyanates and the aromatic dianhydride are under the protection of nitrogen and at the temperature of 0-40 ℃.
7. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: two different aromatic diisocyanates and aromatic dianhydride are fully stirred to obtain intermediate product polyamic acid, and the solid content of the polyamic acid is between 13 and 16 weight percent.
8. The method for producing a polyimide porous membrane according to claim 1 or 2, characterized in that: the heat treatment adopts step temperature rise.
9. The method for producing a polyimide porous membrane according to claim 3, characterized in that: the two different aromatic diisocyanates are 4, 4' -methylenebis (phenylisocyanate) and 4-methyl-m-phenylene diisocyanate; the aromatic dianhydride is 1,2,4, 5-benzenetetracarboxylic dianhydride.
10. The method for producing a polyimide porous membrane according to claim 9, characterized in that: the molar ratio of the sum of the molar amounts of the 4, 4' -methylenebis (phenyl isocyanate) and the 4-methyl-m-phenylene diisocyanate to the 1,2,4, 5-pyromellitic dianhydride is 1: 1.
11. The method for producing a polyimide porous membrane according to claim 5, characterized in that: the pore-forming agent is SiO2Said SiO2Is nano-scale SiO2。
12. The method for producing a polyimide porous membrane according to claim 11, characterized in that: the nano-scale SiO2The average particle diameter of (B) is 5 to 45 nm.
13. A polyimide porous film characterized by: is prepared by the preparation method of any one of claims 1 to 12.
CN202110533302.5A 2021-05-17 2021-05-17 Polyimide porous membrane and preparation method thereof Active CN113248773B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202110533302.5A CN113248773B (en) 2021-05-17 2021-05-17 Polyimide porous membrane and preparation method thereof
PCT/CN2022/092540 WO2022242547A1 (en) 2021-05-17 2022-05-12 Polyimide porous membrane and preparation method therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110533302.5A CN113248773B (en) 2021-05-17 2021-05-17 Polyimide porous membrane and preparation method thereof

Publications (2)

Publication Number Publication Date
CN113248773A true CN113248773A (en) 2021-08-13
CN113248773B CN113248773B (en) 2022-07-08

Family

ID=77182257

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110533302.5A Active CN113248773B (en) 2021-05-17 2021-05-17 Polyimide porous membrane and preparation method thereof

Country Status (2)

Country Link
CN (1) CN113248773B (en)
WO (1) WO2022242547A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114300807A (en) * 2021-12-19 2022-04-08 上海凯矜新材料科技有限公司 Preparation method of lithium battery diaphragm
WO2022242547A1 (en) * 2021-05-17 2022-11-24 上海瑞暨新材料科技有限公司 Polyimide porous membrane and preparation method therefor
CN116381430A (en) * 2023-04-06 2023-07-04 北京西能电子科技发展有限公司 Novel ultrahigh frequency-piezoelectric ultrasonic integrated sensing device and application thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006022260A (en) * 2004-07-09 2006-01-26 Nitto Denko Corp Porous polyimide and method for producing the same
CN101684182A (en) * 2008-09-25 2010-03-31 比亚迪股份有限公司 Preparation method of polyimide film
CN109280190A (en) * 2018-08-01 2019-01-29 乳源东阳光氟树脂有限公司 A kind of polyimide porous film and preparation method thereof

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR112012001481B8 (en) * 2009-07-23 2023-05-09 Evonik Fibres Gmbh POLYIMIDE MEMBRANES, AND THEIR PREPARATION PROCESS
BR112015028307B1 (en) * 2013-06-21 2022-04-05 Evonik Fibres Gmbh Polyimide membrane production method
KR101503332B1 (en) * 2013-12-18 2015-03-18 에스케이씨코오롱피아이 주식회사 Polyimide film and preparation method thereof
JP6596196B2 (en) * 2014-09-05 2019-10-23 東京応化工業株式会社 Method for producing varnish for producing porous membrane
KR101728100B1 (en) * 2015-01-21 2017-04-18 에스케이씨코오롱피아이 주식회사 Method for preparation of polyimide film using porous particles and polyimide film having low permittivity
KR20190025072A (en) * 2017-08-02 2019-03-11 에스케이씨코오롱피아이 주식회사 Method for preparation of polyimide film using fumed silica particles and polyimide film having low permittivity
CN113248773B (en) * 2021-05-17 2022-07-08 上海瑞暨新材料科技有限公司 Polyimide porous membrane and preparation method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006022260A (en) * 2004-07-09 2006-01-26 Nitto Denko Corp Porous polyimide and method for producing the same
CN101684182A (en) * 2008-09-25 2010-03-31 比亚迪股份有限公司 Preparation method of polyimide film
CN109280190A (en) * 2018-08-01 2019-01-29 乳源东阳光氟树脂有限公司 A kind of polyimide porous film and preparation method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022242547A1 (en) * 2021-05-17 2022-11-24 上海瑞暨新材料科技有限公司 Polyimide porous membrane and preparation method therefor
CN114300807A (en) * 2021-12-19 2022-04-08 上海凯矜新材料科技有限公司 Preparation method of lithium battery diaphragm
CN116381430A (en) * 2023-04-06 2023-07-04 北京西能电子科技发展有限公司 Novel ultrahigh frequency-piezoelectric ultrasonic integrated sensing device and application thereof

Also Published As

Publication number Publication date
WO2022242547A1 (en) 2022-11-24
CN113248773B (en) 2022-07-08

Similar Documents

Publication Publication Date Title
CN113248773B (en) Polyimide porous membrane and preparation method thereof
CN107108926B (en) Method for producing polyimide film using porous particles and low dielectric constant polyimide film
KR101831009B1 (en) Aqueous polyimide precursor solution composition and method for producing aqueous polyimide precursor solution composition
KR101503332B1 (en) Polyimide film and preparation method thereof
CN103524768A (en) Novel electronic-grade polyimide film with low linear expansion coefficient and production method thereof
CN108794748B (en) Polyimide film with low dielectric constant and preparation method thereof
CN109627439B (en) Polyimide containing caged phosphate ester structure and preparation method thereof
EP2596949A1 (en) Process for production of polyimide film laminate, and polyimide film laminate
CN111087812B (en) Colorless transparent polyimide film with stable dimension and preparation method thereof
CN111748113A (en) Heat-resistant polyimide film with low dielectric constant and preparation method thereof
KR20230126703A (en) Aqueous dispersion and its preparation method
CN111925543A (en) Low-humidity low-thermal expansion coefficient polyimide composite film material and preparation method thereof
CN112646179B (en) Low-dielectric polyimide film and preparation method thereof
CN111072964B (en) Polyimide precursor composition and preparation method and application thereof
CN100422243C (en) Method of preparing ultra low dielectric constant polyimide membrane by polyamide ester precursor phase transformation
CN114085379B (en) Preparation method of flexible colorless transparent polyimide film
CN111087813B (en) Polyimide film with stable size and preparation method thereof
CN114940760A (en) Polyimide film and preparation method and application thereof
CN115612097A (en) Nano composite material with low dielectric constant and high strength and preparation method thereof
CN112409595B (en) Polyimide film and preparation method thereof
JP2023035685A (en) Polyimide precursor solution, porous polyimide film, and insulated wire
CN113372591A (en) Method for rapidly preparing ultrathin polyimide film
CN110358134A (en) A kind of low dielectric coefficient polyimide film and preparation method thereof
CN114106557B (en) Ultrathin acid-base compound high-temperature proton exchange membrane and preparation method thereof
US9518151B2 (en) Low dielectric constant polymer containing dinaphthyl and hexafluorocyclobutyl ether unit, preparation method and use

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant