A benzocyclobutene-terminated bis-ester bis-imide monomer and methods of making and curing the same
By preparing benzocyclobutene-terminated diester bisimide monomers, the problems of large film shrinkage and environmental unfriendliness in polyimide preparation were solved, realizing the processing and curing of efficient and environmentally friendly polyimide materials with excellent thermal stability and dielectric properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGHAN UNIVERSITY
- Filing Date
- 2023-09-28
- Publication Date
- 2026-07-21
AI Technical Summary
Existing polyimide preparation processes suffer from high film shrinkage due to moisture loss during thermal or chemical imidization. Furthermore, addition-type polyimide preparation processes are not environmentally friendly and are difficult to achieve efficient processing and curing.
A benzocyclobutene-terminated diester diimide monomer is used to prepare a monomer with excellent processing properties by reacting it with 4-aminobenzocyclobutene, trimellitic anhydride, phenolic compounds and acid absorbent in an organic solvent. Polyimide films are then prepared by heating and melting or casting methods to avoid the generation of small molecules.
This method achieves high transparency, excellent dielectric properties, and thermal stability in polyimide materials, while also being environmentally friendly in its preparation process, exhibiting high reaction conversion rates, and simplifying purification steps.
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Figure CN117327004B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing and curing a benzocyclobutene-terminated diester diimide monomer, belonging to the field of polymer materials. Background Technology
[0002] Polyimides are a class of polymers whose main chain contains an imide ring. The rigid imide structure endows polyimides with unique properties, giving them excellent heat resistance and superior mechanical, electrical, radiation resistance, and solvent resistance. Polyimides can be prepared in two ways: condensation and addition. Condensation-type polyimides can be prepared using a one-step chlorobenzene / m-cresol solvent method or a two-step method: first... N,N -Dimethylacetamide / N-methylpyrrolidone / N,N Polyamic acid is generated in dimethylformamide solvent, and then imidized by heating (approximately 300 °C). o C), or chemical imidization with acetic anhydride / acetyl chloride / thionyl chloride reagent. During thermal or chemical imidization, the escape of moisture can cause significant shrinkage of the film. The preparation of addition-type polyimides is environmentally friendly, does not generate small molecules, and is simple to thermoset.
[0003] Benzocyclobutene groups possess excellent processing properties. They undergo thermal ring-opening above 200°C, forming an eight-membered ring through a [4+4] addition reaction, leading to dimers or polymers. The reaction requires no catalyst and produces no small molecules, resulting in pure products with low shrinkage. Therefore, benzocyclobutene groups can be used to prepare addition-type polyimide materials. This leads to the invention of a benzocyclobutene-terminated diester bisimide monomer, along with its preparation and curing methods, which are highly beneficial. Summary of the Invention
[0004] The purpose of this invention is to provide a benzocyclobutene-terminated diester bisimide monomer, its preparation method, and a curing method. This monomer is soluble in the low-boiling-point solvent dichloromethane, exhibits excellent processing properties, and can be directly heated and melt-cured to form polyimide films or prepared via casting. The curing process requires only heating and does not release any small molecules. The resulting polyimide material exhibits excellent thermal stability, high transparency, and excellent dielectric properties.
[0005] A benzocyclobutene-terminated diester diimide monomer has the following general chemical structural formula: Where R is: , , , , , , or .
[0006] The preferred value for R is: , , or .
[0007] The preparation method of the present invention includes the following steps: (1) adding 4-aminobenzocyclobutene and trimellitic anhydride to an organic solvent and reacting to prepare an imide containing a carboxyl group of benzocyclobutene, the structural formula of which is: .
[0008] (2) Add the carboxyl-containing benzocyclobutene imide prepared in step (1), sulfoxide, and acid absorbent to an organic solvent to react and prepare a benzocyclobutene imide containing acyl chloride, the structural formula of which is: .
[0009] (3) Add the benzocyclobutene imide containing acyl chloride prepared in step (2), phenolic compounds and acid absorbent to an organic solvent, and react them. Separate the reaction product to obtain a benzocyclobutene-terminated diester diimide monomer, the general structural formula of which is as follows: Where R is: , , , , , , or .
[0010] A preferred preparation method of the present invention is as follows: the organic solvent is glacial acetic acid, toluene, or tetrahydrofuran. The acid absorbent is pyridine or triethylamine. The molar ratio of the reaction in step (1) is: 4-aminobenzocyclobutene: trimellitic anhydride: solvent = 1:1:40-50, and the reaction is carried out at 120°C. o The reaction is carried out at C for 20-28 h. The molar ratio of the reaction in step (2) is: (1) the prepared imide: sulfoxide: acid absorbent: solvent = 1 : 3 : 1 : 40-50, at 60 o The reaction is carried out at C for 4-6 h. The molar ratio of the reaction in step (3) is: (2) the prepared acyl chloride: phenolic compound: acid absorbent: solvent = 2 : 1 : 2 : 50-100, at 60 o The reaction is carried out at C for 20-28 h, and the preferred structures of the phenolic compounds used are as follows: , , or .
[0011] After the reaction in step (3) is complete, add 3-4 times the volume of anhydrous methanol to the reactants. A white solid precipitates out and is then filtered to obtain the product.
[0012] The present invention also provides a method for curing benzocyclobutene-terminated diester bisimide monomers, characterized in that: it is directly heated to melt and cure into shape or dissolved in a solvent and then spin-coated and cured on a substrate, and cross-linking and curing occurs at 250℃-280℃ to form a polyimide material.
[0013] The monomers prepared by this invention are soluble in the low-boiling-point solvent dichloromethane and possess excellent processing properties. They can be directly heated to melt and solidify into shape or used to prepare polyimide films via casting. The preparation method of this invention is simple, easy to control, has a high reaction conversion rate, and is relatively easy to purify after the reaction. The prepared imides can be directly polymerized into polyimide materials via thermal ring-opening polymerization, which is environmentally friendly and does not generate small molecules. The polyimide materials prepared by this invention have excellent thermal stability, high transparency, and excellent dielectric properties, and can be used as thermosetting polymer materials in fields such as 5G communication, microelectronics, and packaging materials. Attached Figure Description
[0014] Figure 1 This is the 1H NMR spectrum of the benzocyclobutene-terminated diester diimide monomer prepared by the method of this invention.
[0015] Figure 2 This is the DSC spectrum of the benzocyclobutene-terminated diester diimide monomer prepared by the method of this invention.
[0016] Figure 3 This is the TGA spectrum of the benzocyclobutene-terminated diester diimide monomer prepared by the method of this invention. Detailed Implementation
[0017] A method for preparing a benzocyclobutene-terminated diester diimide monomer, comprising the following steps: (1) Add 4-aminobenzocyclobutene and trimellitic anhydride to anhydrous reagent in a molar ratio of 4-aminobenzocyclobutene: trimellitic anhydride: reagent = 1:1:40-50, and heat at 120°C. o The structural formula of the benzocyclobutene imide containing a carboxyl group prepared by reacting at C for 20-28 h is as follows: (2) Add the imide, sulfoxide, and pyridine prepared in step (1) to anhydrous reagent in a molar ratio of (1) prepared imide: sulfoxide: pyridine: reagent = 1: 3: 1: 40-50. React at 60 °C for 4-6 h. The structural formula of the benzocyclobutene imide containing acyl chloride is: (3) Add the acyl chloride prepared in step (2), various phenolic compounds, and pyridine to anhydrous reagent in a molar ratio of: (2) prepared acyl chloride: phenolic compounds: pyridine: reagent = 2: 1: 2: 50-100, and add at 60°C. o The reaction was carried out at C for 20-28 h, and the structures of the phenolic compounds used are as follows: (4) Add 3-4 times the volume of anhydrous methanol to the reactants in step (3) above. A white solid precipitates out, and the product is obtained by filtration. It has the following chemical formula: Where R is: , , , , , , , .
[0018] The following are specific examples of the benzocyclobutene-terminated diester diimide monomers of the present invention: The structures of the four embodiments are listed below: (Compound BBIA-BPA is a bis(2,3-dihydro-1,3-dioxo-2-(bicyclo[4.2.0]oct-1,3,5-trien-3-yl)-1H-isoindole-5-carboxylic acid) bisphenol A ester) (Compound BBIA-BPS bis(2,3-dihydro-1,3-dioxo-2-(bicyclo[4.2.0]oct-1,3,5-trien-3-yl)-1H-isoindole-5-carboxylic acid) bisphenol S ester) (Compound BBIA-BPAF bis(2,3-dihydro-1,3-dioxo-2-(bicyclo[4.2.0]oct-1,3,5-trien-3-yl)-1H-isoindole-5-carboxylic acid) bisphenol AF ester) (Compound BBIA-DBA bis(2,3-dihydro-1,3-dioxo-2-(bicyclo[4.2.0]oct-1,3,5-trien-3-yl)-1H-isoindole-5-carboxylic acid) 2,2'-diallyl bisphenol A ester) [Example 1] Synthesis of the benzocyclobutene-terminated diester diimide monomer of the present invention 1 Compound BBIA-BPA is a bis(2,3-dihydro-1,3-dioxo-2-(bicyclo[4.2.0]oct-1,3,5-trien-3-yl)-1H-isoindole-5-carboxylic acid) bisphenol A ester. 1.904 g (16.0 mmol) of 4-aminobenzocyclobutene and 3.070 g (16.0 mmol) of trimellitic anhydride were placed in a 200 mL round-bottom flask. Under nitrogen atmosphere, 40 mL of glacial acetic acid was added. The solution was then heated to 120 °C. o Stirred and refluxed at C for 24 h, cooled to room temperature, and 120 mL of deionized water was added. A yellow solid precipitated out. The mixture was filtered under reduced pressure and washed three times with deionized water to obtain an imide containing a carboxyl group and benzocyclobutene. Figure 1 As shown, the analysis of the proton NMR spectrum of this invention is as follows: 1 H NMR (400 MHz, DMSO):13.75 (s, 1H), 8.41 (d, J = 7.7 Hz, 1H), 8.30(s, 1H), 8.07 (d, J = 7.7 Hz, 1H), 7.23 (s, 2H), 7.15 (s, 1H), 3.20 (s, 4H).
[0019] Take 1.173 g (4.00 mmol) of the above product, 20 mL of toluene, and two drops of... N,N Dimethylformamide was placed in a 200 mL round-bottom flask. Under nitrogen atmosphere and in an ice-water bath, 1.0 mL of thionyl chloride (1.64 g, 13.8 mmol) was added. After 10 min, 0.5 mL of pyridine (0.49 g, 6.2 mmol) was added, and the mixture was incubated at 60 °C. o Stirred and refluxed at C for 4 h. Cooled to room temperature, the solvent was removed by rotary evaporation to obtain an imide containing benzocyclobutene chloride.
[0020] Add 0.457 g (2.00 mmol) of bisphenol A to the round-bottom flask containing the acyl chloride. Under nitrogen atmosphere, add 20 mL of anhydrous tetrahydrofuran and 0.5 mL (0.49 g, 6.2 mmol) of pyridine sequentially. Incubate at 65°C. o The mixture was stirred and refluxed at C for 24 h. After cooling to room temperature, 60 mL of anhydrous methanol was added and the mixture was stirred for 0.5 h. A large amount of white solid precipitated out. The solid was filtered under reduced pressure and washed three times with anhydrous methanol to obtain 1.146 g of compound BBIA-BPA, with a yield of 73.5%, which was a white solid. Figure 2 The DSC spectrum of embodiment 1 shows that the present invention is solidified after melting. Figure 3 The TGA spectrum of embodiment 1 shows that the thermal stability of the present invention after molding is very good.
[0021] 1 H NMR (400 MHz, CDCl3):8.76 (s, 2H), 8.63 (d, J = 7.7 Hz, 2H), 8.19-8.02 (m, 2H), 7.35 (d, J = 8.2 Hz, 4H), 7.24-7.05 (m, 10H), 3.24 (s, 8H), 1.75 (s, 6H). The reaction process is as follows: [Example 2] Synthesis of the benzocyclobutene-terminated diester diimide monomer of the present invention 2 Compound BBIA-BPS The synthesis of benzocyclobutene imides containing carboxyl groups is the same as in [Example 1].
[0022] The synthesis of acyl chlorides is the same as in [Example 1].
[0023] Add 0.501 g (2.00 mmol) of bisphenol S to the round-bottom flask containing the acyl chloride. Under nitrogen atmosphere, add 20 mL of anhydrous tetrahydrofuran and 0.5 mL (0.49 g, 6.2 mmol) of pyridine sequentially. Incubate at 65°C. o The mixture was stirred and refluxed at C for 24 h. After cooling to room temperature, 60 mL of anhydrous methanol was added and the mixture was stirred for 0.5 h. A large amount of white solid precipitated out. The solid was filtered under reduced pressure and washed three times with anhydrous methanol to give 1.396 g of compound BBIA-BPS, with a yield of 87.1%. The solid was white.
[0024] 1H NMR (400 MHz, CDCl3): 8.74 (s, 2H), 8.62 (d, J = 7.6 Hz, 2H),8.19-7.94 (m, 6H), 7.48 (d, J = 8.3 Hz, 4H), 7.21 (s, 4H), 7.09 (s, 2H), 3.24 (s, 8H). Reaction process: [Example 3] Synthesis of the benzocyclobutene-terminated diester diimide monomer of the present invention 3 Compound BBIA-BPAF The synthesis of benzocyclobutene imides containing carboxyl groups is the same as in [Example 1].
[0025] The synthesis of acyl chlorides is the same as in [Example 1].
[0026] Add 0.672 g (2.00 mmol) of bisphenol AF to the round-bottom flask containing the acyl chloride. Under nitrogen atmosphere, add 20 mL of anhydrous tetrahydrofuran and 0.5 mL (0.49 g, 6.2 mmol) of pyridine sequentially, and incubate at 65°C. o The mixture was stirred and refluxed at C for 24 h. After cooling to room temperature, 60 mL of anhydrous methanol was added and the mixture was stirred for 0.5 h. A large amount of white solid precipitated out. The solid was filtered under reduced pressure and washed three times with anhydrous methanol to obtain 1.513 g of compound BBIA-BPAF, with a yield of 85.3%, which was a white solid.
[0027] 1 H NMR (400 MHz, CDCl3):8.77 (s, 2H), 8.64 (d, J = 7.8 Hz, 2H), 8.12(d, J = 7.6 Hz, 2H), 7.55 (d, J = 8.5 Hz, 4H), 7.34 (d, J = 8.4 Hz, 4H), 7.21 (s, 4H), 7.10 (s, 2H), 3.25 (s, 8H). 19 F NMR (376 MHz, CDCl3): -63.79. Reaction process: [Example 4] Synthesis of the benzocyclobutene-terminated diester diimide monomer of the present invention 4 Compound BBIA-DBA The synthesis of benzocyclobutene imides containing carboxyl groups is the same as in [Example 1].
[0028] The synthesis of acyl chlorides is the same as in [Example 1].
[0029] Add 0.684 g (2.22 mmol) of DBA to the round-bottom flask containing the acyl chloride. Under nitrogen atmosphere, add 20 mL of anhydrous tetrahydrofuran and 0.5 mL (0.49 g, 6.2 mmol) of pyridine sequentially. Incubate at 65°C. o The mixture was stirred and refluxed at C for 24 h. After cooling to room temperature, 60 mL of anhydrous methanol was added and the mixture was stirred for 0.5 h. A large amount of white solid precipitated out. The solid was filtered under reduced pressure and washed three times with anhydrous methanol to obtain 0.800 g of compound BBIA-DBA, with a yield of 46.3%, which was a white solid.
[0030] 1 H NMR (400 MHz, CDCl3):8.74 (s, 2H), 8.61 (d, J = 7.8 Hz, 2H), 8.10(d, J = 7.8 Hz, 2H), 7.24-6.93 (m, 12H), 5.88 (td, J = 16.5, 6.4 Hz, 2H),5.16-4.71 (m, 4H), 3.35 (d, J = 6.5 Hz, 4H), 3.24 (s, 8H), 1.73 (s, 6H). Reaction process: [Example 5] Curing of BBIA-BPA prepared in [Example 1] of the present invention A certain mass of benzocyclobutene-terminated diester diimide monomer BBIA-BPA powder was placed on a clean glass substrate and heated to 250℃ to melt the powder into a pale yellow, low-viscosity liquid. While still hot, the powder was cast and spread evenly, then placed in an oven for curing under a nitrogen atmosphere. The heating program was 270℃ for 1.5 hours and 300℃ for 0.5 hours, resulting in a smooth, pale yellow, transparent cured film. DSC curing behavior analysis showed that BBIA-BPA has a melting point of 244℃ and crosslinks at 272℃. Thermogravimetric analysis showed that the initial decomposition temperature (5% weight loss) was 445℃, and the residual carbon content at 800℃ was 37%.
[0031] Curing process: .
Claims
1. A benzocyclobutene-terminated diester diimide monomer, with the following general chemical formula: Where R is: , , 、 、 or .
2. The benzocyclobutene-terminated diester diimide monomer according to claim 1, wherein R is: , , or 。 3. A method for preparing a benzocyclobutene-terminated diester diimide monomer, comprising the following steps: (1) Add 4-aminobenzocyclobutene and trimellitic anhydride to an organic solvent and react to prepare an imide containing a carboxyl group of benzocyclobutene, the structural formula of which is: ； (2) Add the carboxyl-containing benzocyclobutene imide prepared in step (1), sulfoxide, and acid absorbent to an organic solvent to react and prepare a benzocyclobutene imide containing acyl chloride, the structural formula of which is: ； (3) Add the benzocyclobutene imide containing acyl chloride prepared in step (2), phenolic compounds and acid absorbent to an organic solvent, and react them. Separate the reaction product to obtain a benzocyclobutene-terminated diester diimide monomer, the general structural formula of which is as follows: Where R is: , , , , , , or .
4. The method for preparing a benzocyclobutene-terminated diester diimide monomer according to claim 3, wherein the organic solvent is glacial acetic acid, toluene, or tetrahydrofuran.
5. The method for preparing a benzocyclobutene-terminated diester bisimide monomer according to claim 3, wherein the acid absorbent is pyridine or triethylamine.
6. The method for preparing a benzocyclobutene-terminated diester diimide monomer according to claim 3, wherein the molar ratio of the reaction in step (1) is: 4-aminobenzocyclobutene: trimellitic anhydride: organic solvent = 1:1:40-50, and the reaction is carried out at 120 °C for 20-28 h.
7. The method for preparing a benzocyclobutene-terminated diester bisimide monomer according to claim 3, wherein the molar ratio of the reaction in step (2) is: (1) the prepared imide: sulfoxide: acid absorbent: organic solvent = 1: 3: 1: 40-50, and the reaction is carried out at 60 °C for 4-6 h.
8. The method for preparing a benzocyclobutene-terminated diester bisimide monomer according to claim 3, wherein the molar ratio of the reaction in step (3) is: (2) the prepared acyl chloride: phenolic compound: acid absorbent: organic solvent = 2: 1: 2: 50-100, and the reaction is carried out at 60 °C for 20-28 h.
9. The method for preparing a benzocyclobutene-terminated diester diimide monomer according to claim 3, wherein after the reaction in step (3) is completed, 3-4 times the volume of anhydrous methanol is added to the reactants, a white solid is precipitated, and the product is obtained by filtration.