A polyimide containing a pyridine structure, and a preparation method and application thereof

Abstract

The application provides a kind of pyridine structure containing polyimide and its preparation method and application.The structural formula of the polyimide is as shown in formula (II) or formula (III):in formula (II), m and n are positive integers, and m≥n≥10;Group is the group containing fluorine phenyl group.Polyimide shown in formula (II) introduces bulky group and trifluoromethyl at the same time, also introduces hydroxyl group, realizes polyimide platform, provides the possibility for subsequent introduction of other different groups;Chemical imine method and thermal imine method are combined in the process of imidization, compared with traditional method, the time required for imidization is shortened.Hydroxyl group is introduced into the polyimide shown in formula (II), which significantly reduces the dielectric constant;Polyimide shown in formula (III) introduces fluorobenzene structure on the basis of polyimide shown in formula (II), further realizes the reduction of polyimide dielectric constant.

Description

Technical Field

[0001] This invention relates to the field of organic materials, and in particular to a polyimide containing a pyridine structure, its preparation method, and its application. Background Technology

[0002] With the advent of the 5G era, microelectronic devices are becoming increasingly miniaturized and multifunctional, leading to a series of problems such as reduced diffraction capability of electromagnetic waves, increased signal transmission attenuation, and exacerbated parasitic resistance and capacitance effects within circuits. These problems severely affect the performance of electronic components. Therefore, exploring methods to reduce the dielectric constant of materials has become particularly urgent.

[0003] Traditional polyimide (PI) has a relatively high dielectric constant (approximately 3.0), and methods to reduce the dielectric constant of PI mainly include introducing bulky groups, CF bonds, or fluorinated diamines or dianhydrides. These methods have achieved some success, as shown in patent documents such as CN1580095A, CN112646182A, CN113248709A, and CN115433121A. However, these methods involve long imidization times, and even with improvements, the dielectric constant can only be reduced to around 2.5. Such performance improvements clearly cannot meet the urgent demand in advanced electronics fields for materials with even lower dielectric constants.

[0004] Therefore, developing a new type of polyimide material with a lower dielectric constant to meet the high material performance requirements of microelectronic devices in the 5G era has become an urgent technical challenge.

[0005] Therefore, there is an urgent need for methods to introduce bulky groups and CF bonds into PI to meet the increasingly pressing technological needs of the advanced electronics field. Summary of the Invention

[0006] The purpose of this invention is to provide a polyimide containing a pyridine structure and a method for its preparation.

[0007] This invention provides a polyimide containing a pyridine structure, the structural formula of which is shown in formula (II):

[0008]

[0009] In equation (II), m and n are positive integers, and m ≥ n ≥ 10.

[0010] The present invention also provides a method for preparing the polyimide shown in formula (II), comprising the following steps:

[0011] S1. The diamine monomer shown in formula (Ⅰ), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB) and bisphenol A type diether dianhydride are subjected to a condensation reaction to obtain polyamic acid;

[0012]

[0013] S2. Add a dehydrating agent and a catalyst to imidize polyamic acid to obtain polyimide.

[0014] Further, in step S1, the condensation reaction temperature is 15–30°C; in step S2, the imidization temperature is 170–190°C.

[0015] One method for preparing a diamine monomer of formula (I) includes the following steps:

[0016] Under an inert gas atmosphere, p-hydroxybenzaldehyde, p-nitrosoacetophenone, and ammonium acetate were added to a solvent and reacted at 110-125℃. After the reaction was complete, the reaction solution was filtered, dried, and recrystallized to obtain the intermediate shown in formula (A).

[0017]

[0018] The intermediate shown in formula (A) and hydrazine hydrate are reacted with palladium on carbon catalyst under inert gas protection at 70-80°C. After the reaction is complete, the mixture is filtered, the filter cake is dissolved in a solvent, and the catalyst is removed by filtration. The filtrate is then added dropwise to deionized water to obtain the diamine monomer shown in formula (I).

[0019] For example, inert gases can be nitrogen, argon, helium, etc.

[0020] Furthermore, the molar ratio of p-hydroxybenzaldehyde, p-nitroacetophenone, and ammonium acetate is 1:(2-2.5):(12-14).

[0021] The present invention also provides another polyimide containing a pyridine structure, the polyimide having the general formula shown in formula (III):

[0022]

[0023] in: The group is a fluorinated phenyl group.

[0024] According to a specific embodiment of the present invention, The functional group is selected from the structure shown in formula (B1), formula (B2), or formula (B3):

[0025]

[0026] The present invention also provides a method for preparing the polyimide shown in formula (III), comprising the following steps:

[0027] Under a nitrogen atmosphere and in the presence of an alkaline substance, the polyimide shown in formula (II) reacts with fluorinated benzoyl chloride to obtain the polyimide shown in formula (III).

[0028] The present invention also provides a polyimide film, wherein the polyimide in the film is the polyimide shown in formula (II) and / or the polyimide shown in formula (III).

[0029] The present invention also provides a method for preparing a polyimide film, wherein the polyimide shown in formula (II) and / or the polyimide shown in formula (III) are dissolved in a solvent, filtered through a filter membrane, and then spin-coated onto a glass plate; the spin-coated glass is dried to remove the solvent in the coating and to cure the polyimide into a film; the dried glass plate is then placed in deionized water to peel the polyimide film off the glass plate, thereby obtaining the polyimide film.

[0030] Compared with existing technologies, this invention has the following advantages: This technology introduces hydroxyl groups into polyimide while simultaneously introducing bulk groups and CF bonds. The introduction of hydroxyl groups allows for the introduction of other different groups after the polyimide is synthesized, enabling the exploration of the effects of different groups on the dielectric and other properties of the polyimide, thus achieving a platform-based approach to polyimide development. The polyimide shown in Formula (II) combines chemical imidization and thermal imidization methods during the imidization process, shortening the imidization time compared to traditional methods. The polyimide shown in Formula (II) introduces hydroxyl groups along with bulk groups and trifluoromethyl groups, achieving a platform-based approach to polyimide development. This provides the possibility for the subsequent introduction of other different groups, allowing for a more comprehensive exploration of the effects of different groups on the dielectric and other physical properties of the polyimide. This platform-based design broadens the modification space of polyimide, providing the possibility for customized design of high-performance materials (such as improving heat resistance and enhancing mechanical properties). The polyimide of formula (II) with the introduction of hydroxyl groups significantly reduces the dielectric constant; the polyimide of formula (III) introduces a fluorobenzene structure on the basis of the polyimide of formula (II), which further reduces the dielectric constant of the polyimide.

[0031] In summary, this invention provides a novel approach and method for preparing high-performance polyimide materials by innovatively combining multi-element modification, improving imidization efficiency, effectively reducing dielectric constant, and realizing multifunctionality and customization potential. It has significant technical advantages and broad application prospects. Attached Figure Description

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 This is the 1H NMR spectrum of the diamine monomer shown in formula (I) of this invention;

[0034] Figure 2 This is the 1H NMR spectrum of the polyimide shown in formula (II) of this invention;

[0035] Figure 3 This is the 1H NMR spectrum of the polyimide represented by formula (Ⅲ-B1) of this invention;

[0036] Figure 4 This is the NMR fluorine spectrum of the polyimide represented by formula (Ⅲ-B1) of this invention.

[0037] Figure 5 This is the 1H NMR spectrum of the polyimide represented by formula (Ⅲ-B2) of this invention;

[0038] Figure 6 This is the NMR fluorine spectrum of the polyimide represented by formula (Ⅲ-B2) of this invention.

[0039] Figure 7 This is the 1H NMR spectrum of the polyimide represented by formula (Ⅲ-B3) of this invention;

[0040] Figure 8 This is the NMR fluorine spectrum of the polyimide represented by formula (Ⅲ-B3) of this invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions in this application, the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application. Unless otherwise stated, percentages in this invention refer to mass percentages.

[0042] The diamine monomer shown in formula (I) of this invention contains a pyridine structure, and its preparation method includes the following steps:

[0043] 1) Using p-hydroxybenzaldehyde, p-nitroacetophenone and ammonium acetate as raw materials, and acetic acid as solvent; under a nitrogen atmosphere, p-hydroxybenzaldehyde, p-nitroacetophenone and ammonium acetate in a molar ratio of 1:(2~2.5):(12~14) are added to the solvent, stirred and heated, and reacted at 125℃ for 12 hours; after the reaction is completed, the reaction solution is filtered, the filter cake is repeatedly washed with acetic acid, filtered, dried and recrystallized to obtain the intermediate shown in formula (A).

[0044] The reaction equations for the above process are shown below:

[0045]

[0046] 2) Using ethanol as solvent; under a nitrogen atmosphere, add the intermediate shown in formula (A) and the Pd / C catalyst to the solvent, stir, slowly add hydrazine hydrate, and after the addition is complete, heat to 80℃ and react for 8 to 12 hours; after the reaction is complete, filter the reaction solution, dissolve the filter cake with N,N-dimethylformamide (DMF) and filter to remove Pd / C, and slowly add the filtrate to deionized water to obtain the diamine monomer shown in formula (I).

[0047] The reaction equations for the above process are shown below:

[0048]

[0049] The polyimide of formula (II) containing a pyridine structure of the present invention is synthesized by polymerizing the diamine monomer of formula (I) with 6FAPB and BPADA. The preparation method includes the following steps:

[0050] S1. Accurately weigh the dried diamine monomer shown in formula (I) and 6FAPB, and add them to a dry three-necked flask under a nitrogen atmosphere. Add solvent and stir until the diamine monomer shown in formula (I) and 6FAPB are completely dissolved. Then add the dried dianhydride monomer. The molar ratio of the diamine monomer shown in formula (I), 6FAPB and dianhydride is preferably controlled at 1:1:2. Rinse the mouth of the flask with solvent. Stir the reaction at 15-30℃ for 20-30 hours; the reaction solution is pale yellow and transparent with high viscosity. The solvent used in step S1 is anhydrous N-methylpyrrolidone (NMP).

[0051] S2. Add the catalyst and dehydrating agent to the above reaction solution (S1), and stir continuously at 180°C for 3–4 hours. Terminate the reaction, slowly add the reaction solution to ethanol for washing, and a pale yellow powder precipitates out. Filter and dry to obtain the pale yellow powdery solid, which is the polyimide shown in formula (II). The catalyst can be pyridine, and the dehydrating agent can be γ-valerolactone.

[0052] The reaction equations for the above process are shown below:

[0053]

[0054] The polyimide of formula (III) containing a fluorine and pyridine structure of the present invention is prepared by reacting the polyimide of formula (II) with fluorobenzoyl chloride. The preparation method includes the following steps:

[0055] In a nitrogen atmosphere, polyimide and cesium carbonate of formula (II) are added to a solvent; the solvent is tetrahydrofuran (THF); after stirring until the polyimide of formula (II) is completely dissolved, fluorobenzoyl chloride is slowly added dropwise under an ice-water bath. After the addition is complete, the reaction is carried out at room temperature for 10 hours. After the reaction is complete, the reaction solution is added dropwise to ethanol and water for washing. The solid precipitates as a powder, which is filtered and dried to obtain the powdered solid, which is the polyimide of formula (III).

[0056] The reaction equations for the above process are shown below:

[0057]

[0058] The polyimide shown in formula (II) and the polyimide shown in formula (III) obtained above can be used to prepare polyimide films. The preparation method is as follows: dissolve the polyimide shown in formula (II) and / or the polyimide shown in formula (III) in a solvent, filter it through a filter membrane, spin-coat it onto a glass plate, place the glass plate in a vacuum oven, and heat it at 60℃, 120℃, 180℃, 240℃, and 300℃ for 20 minutes respectively. Finally, place the glass plate in deionized water, peel off the film, and the polyimide film can be obtained.

[0059] Example 1

[0060] 1) Preparation process of the diamine monomer shown in formula (Ⅰ):

[0061] 225 mL of anhydrous acetic acid was added to a dry 500 mL three-necked flask. 100 mmol of p-hydroxybenzaldehyde, 205 mmol of p-nitroacetophenone, and 1430 mmol of ammonium acetate were added under magnetic stirring. The mixture was heated to 125 °C under nitrogen atmosphere and stirred for 12 hours. The reaction solution was filtered, and the resulting solid was washed with acetic acid until the filtrate was colorless. After filtration and drying, 17.3 g of a pale yellow solid was obtained, with a yield of 41.8%, which was the crude nitro product. The crude nitro product was then recrystallized from DMF at a ratio of m(crude nitro product):V(DMF) = 1:5 at 150 °C. After filtration and drying, 15.6 g of pure nitro product was obtained, with a yield of 90.2%, which is the intermediate shown in formula (A).

[0062] In a dry 500 mL three-necked flask, under a nitrogen atmosphere, 24 mmol of the intermediate shown in formula (A), 200 mL of anhydrous ethanol, and 1 g of Pd / C catalyst (5% active ingredient) were added dropwise with stirring. 40 mL of hydrazine hydrate was then added dropwise (the hydrazine hydrate was slowly added dropwise over 30 min in a dropping funnel). After the hydrazine hydrate addition was complete, the mixture was heated to 80 °C and refluxed with stirring for 12 h. After the reaction was complete, a mixture of Pd / C and the diamine monomer shown in formula (I) was obtained by filtration. 80 mL of DMF was added to the mixture to dissolve the diamine monomer shown in formula (I). Pd / C was removed by filtration, and the filtrate was slowly added to 1500 mL of deionized water for washing. The solid precipitated and was filtered to obtain 7.6 g of a pale yellow solid product, with a yield of 88.9%. This pale yellow solid product is the diamine monomer shown in formula (I), and its 1H NMR spectrum is shown below. Figure 1 .

[0063] 2) Preparation process of polyimide as shown in formula (II):

[0064] Accurately weigh 10 mmol of the dried diamine monomer shown in formula (I), 10 mmol of 6FAPB, and 80 mL of anhydrous NMP, and add them to a dry 250 mL three-necked flask. Stir mechanically under a nitrogen atmosphere until the solid is completely dissolved. Then add 20 mmol of the dried dianhydride monomer BPADA, and rinse the flask mouth with 20 mL of anhydrous NMP. Stir the reaction at 26 °C for 24 hours. The reaction solution is pale yellow and transparent with high viscosity. Add 4.0 mL of pyridine as a catalyst and 800 mg of γ-valerolactone as a dehydrating agent. Stir continuously at 180 °C for 4 hours under a nitrogen atmosphere. Terminate the reaction, and slowly add the reaction solution to 1000 mL of ethanol for washing. The solid precipitates as a pale yellow powder. Filter and dry to obtain 15.5 g of pale yellow powder, with a yield of 88.6%. This pale yellow powder is the polyimide shown in formula (II), and its 1H NMR spectrum is shown below. Figure 2 .

[0065] 3) Preparation process of polyimide as shown in formula (Ⅲ-B1):

[0066] Accurately weigh 2 mmol of dried polyimide (II), 1.5 mmol of cesium carbonate, and 20 ml of anhydrous THF into a dry 100 ml double-necked flask. Stir under a nitrogen atmosphere until the polyimide (II) is completely dissolved. Accurately weigh 1.5 mmol of 4-fluorobenzoyl chloride and slowly add it dropwise to the solution under an ice-water bath. After the addition is complete, stir the reaction for 10 hours. Terminate the reaction and slowly add the reaction solution to a mixture of 500 ml of ethanol and 100 ml of water to wash. The solid precipitates as a powder. Filter and dry to obtain 3.11 g of powdered solid, with a yield of 83.0%. This powdered solid is the polyimide (III-B1), and its 1H NMR spectrum is shown below. Figure 3 The NMR fluorine spectrum is shown in [reference needed]. Figure 4 .

[0067]

[0068] 4) Accurately weigh 2g of dried polyimide of formula (II) and 2g of polyimide of formula (III-B1), dissolve them in 12g of N,N-dimethylacetamide (DMAc), with a solid content of 25%, filter through a filter membrane, and spin-coat them onto a glass plate at a speed of 500r / min for 30 seconds; place the glass plate in a vacuum oven and heat it at 60℃, 120℃, 180℃, 240℃, and 300℃ for 20 minutes respectively. Finally, place the glass plate in deionized water and peel off the film to obtain the polyimide film. The dielectric properties of the obtained polyimide film are shown in Table 1 below.

[0069] Example 2:

[0070] 1) The preparation process of the diamine monomer shown in formula (Ⅰ) is the same as in Example 1.

[0071] 2) The preparation process of the polyimide shown in formula (II) is the same as in Example 1.

[0072] 3) Preparation process of polyimide as shown in formula (Ⅲ-B2):

[0073] Accurately weigh 2 mmol of dried polyimide (II), 1.5 mmol of cesium carbonate, and 20 ml of anhydrous THF into a dry 100 ml double-necked flask. Stir under a nitrogen atmosphere until the polyimide (II) is completely dissolved. Accurately weigh 1.5 mmol of 3,4,5-trifluorobenzoyl chloride and slowly add it dropwise to the solution under an ice-water bath. After the addition is complete, stir the reaction for 10 hours. Terminate the reaction and slowly add the reaction solution to a mixture of 500 ml of ethanol and 100 ml of water to wash. The solid precipitates as a powder. Filter and dry to obtain 3.19 g of powdered solid, with a yield of 83.5%. This powdered solid is the polyimide (III-B2), and its 1H NMR spectrum is shown below. Figure 5 The NMR fluorine spectrum is shown in [reference needed]. Figure 6 .

[0074]

[0075] 4) Accurately weigh 2g of the dried polyimide of formula (Ⅲ-B2), dissolve it in 6g of N,N-dimethylacetamide (DMAc) with a solid content of 25%, filter it through a filter membrane, and spin-coat it onto a glass plate at a speed of 500 r / min for 30 seconds. Place the glass plate in a vacuum oven and heat it at 60℃, 120℃, 180℃, 240℃, and 300℃ for 20 minutes each. Finally, place the glass plate in deionized water and peel off the film to obtain the polyimide film. The dielectric properties of the obtained polyimide film are shown in Table 1 below.

[0076] Example 3:

[0077] 1) The preparation process of the diamine monomer shown in formula (Ⅰ) is the same as in Example 1.

[0078] 2) The preparation process of the polyimide shown in formula (II) is the same as in Example 1.

[0079] 3) Preparation process of polyimide as shown in formula (Ⅲ-B3):

[0080] Accurately weigh 2 mmol of dried polyimide (II), 1.5 mmol of cesium carbonate, and 20 ml of anhydrous THF into a dry 100 ml double-necked flask. Stir under a nitrogen atmosphere until the polyimide (II) is completely dissolved. Accurately weigh 1.5 mmol of 2,3,4,5,6-pentafluorobenzoyl chloride and slowly add it dropwise to the solution under an ice-water bath. After the addition is complete, stir the reaction for 10 hours. Terminate the reaction and slowly add the reaction solution to a mixture of 500 ml of ethanol and 100 ml of water to wash. The solid precipitates as a powder. Filter and dry to obtain 3.20 g of powdered solid, with a yield of 82.3%. This powdered solid is the polyimide (III-B3), and its 1H NMR spectrum is shown below. Figure 7 The NMR fluorine spectrum is shown in [reference needed]. Figure 8 .

[0081]

[0082] 4) Accurately weigh 2g of the dried polyimide of formula (Ⅲ-B3), dissolve it in 6g of N,N-dimethylacetamide (DMAc), with a solid content of 25%, filter it through a filter membrane, and spin-coat it onto a glass plate at a speed of 500r / min for 30 seconds; place the glass plate in a vacuum oven and heat it at 60℃, 120℃, 180℃, 240℃, and 300℃ for 20 minutes respectively. Finally, place the glass plate in deionized water and peel off the film to obtain the polyimide film. The dielectric properties of the obtained polyimide film are shown in Table 1 below.

[0083] Table 1

Claims

1. A polyimide containing a pyridine structure, characterized in that, The structural formula of the polyimide is shown in formula (II) or formula (III): (Ⅱ)， In equation (II), m and n are positive integers, and m ≥ n ≥ 10; (Ⅲ) in: The group is a fluorophenyl group.

2. The polyimide according to claim 1, characterized in that, The functional group is selected from the structure shown in formula (B1), formula (B2), or formula (B3): 。 3. A method for preparing the polyimide containing a pyridine structure as described in claim 1, characterized in that, Includes the following steps: S1. The diamine monomer shown in formula (Ⅰ), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB) and bisphenol A type diether dianhydride are subjected to a condensation reaction to obtain polyamic acid; (Ⅰ) S2. Add a dehydrating agent and a catalyst to imidize the polyamic acid to obtain the polyimide shown in formula (II). The catalyst is pyridine, the dehydrating agent is γ-valerolactone, the imidization temperature is 170-190℃, and the imidization time is 3-4h.

4. The preparation method according to claim 3, characterized in that, In step S1, the temperature of the condensation reaction is 15–30°C.

5. The preparation method according to any one of claims 3 to 4, characterized in that, The method for preparing the diamine monomer shown in formula (I) includes the following steps: Under an inert gas atmosphere, p-hydroxybenzaldehyde, p-nitrosoacetophenone, and ammonium acetate were added to a solvent and reacted at 110-125℃. After the reaction was complete, the reaction solution was filtered, dried, and recrystallized to obtain the intermediate shown in formula (A). (A) The intermediate shown in formula (A) and hydrazine hydrate are reacted with palladium on carbon catalyst under inert gas protection at 70-80°C. After the reaction is complete, the mixture is filtered, the filter cake is dissolved in a solvent, and the catalyst is removed by filtration. The filtrate is then added dropwise to deionized water to obtain the diamine monomer shown in formula (I).

6. The preparation method according to claim 5, characterized in that, The molar ratio of p-hydroxybenzaldehyde, p-nitroacetophenone and ammonium acetate is 1:(2-2.5):(12-14).

7. A method for preparing the polyimide according to claim 1, characterized in that, Includes the following steps: Under a nitrogen atmosphere and in the presence of an alkaline substance, the polyimide shown in formula (II) reacts with fluorinated benzoyl chloride to obtain the polyimide shown in formula (III). The preparation method of the polyimide shown in formula (II) includes the following steps: S1. The diamine monomer shown in formula (Ⅰ), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (6FAPB) and bisphenol A type diether dianhydride are subjected to a condensation reaction to obtain polyamic acid; (Ⅰ) S2. Add a dehydrating agent and a catalyst to imidize the polyamic acid to obtain the polyimide shown in formula (II). The catalyst is pyridine, the dehydrating agent is γ-valerolactone, the imidization temperature is 170-190℃, and the imidization time is 3-4h.

8. A polyimide film, characterized in that, The polyimide in the film is the polyimide of formula (II) as described in claim 1 and / or the polyimide of formula (III).

9. A method for preparing the polyimide film according to claim 8, characterized in that, The polyimide shown in formula (II) and / or the polyimide shown in formula (III) are dissolved in a solvent, filtered through a filter membrane, and then spin-coated onto a glass plate. The spin-coated glass is dried to remove the solvent from the coating and allow the polyimide to solidify into a film. The dried glass plate is then placed in deionized water to peel the polyimide film off the glass plate, thereby obtaining the polyimide film.

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