Diamine monomer, transparent high-temperature-resistant polyesterimide film prepared from diamine monomer and application of transparent high-temperature-resistant polyesterimide film

Abstract

The invention discloses a diamine monomer, a transparent high-temperature-resistant polyester imide film prepared from the diamine monomer and application of the transparent high-temperature-resistant polyester imide film, the diamine monomer is synthesized from 4-aminobenzoic acid and binary primary alcohol or 4-nitrobenzoyl chloride and a phenolic compound, and ester groups with symmetrical structures are introduced into the chemical structure of the monomer, so that the diamine monomer can be synthesized into the transparent high-temperature-resistant polyester imide film. According to the preparation method of the high-temperature-resistant polyester imide film, the polyester imide synthesized with anhydride simultaneously contains imide bonds and ester bonds, so that the correspondingly prepared high-temperature-resistant polyester imide film not only has simple preparation method, but also has excellent optical performance, thermal performance and flexibility, has higher glass transition temperature while keeping higher optical transmittance, and can be used for preparing the high-temperature-resistant polyester imide film. Therefore, the material has good heat resistance and thermal stability, and has good application prospects in the fields of high-temperature-resistant optical films, flexible circuit substrates, lithium battery diaphragm coatings, photoelectric chip substrates and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyester materials, in particular to a diamine monomer, a transparent high-temperature-resistant polyester-imide film prepared from the diamine monomer and an application thereof. BACKGROUND

[0002] As an outstanding representative in the field of material science, polyester film has excellent performance and is widely used in daily life. Polyester materials generally have excellent mechanical properties, high tensile strength, good mechanical stability and other characteristics. In addition, its transparent feature makes it highly concerned in optical instruments. However, on the one hand, Karayannidis G. P. et al. found that the glass transition temperature of polyester is generally low, only about 76℃, and it is easy to deform when it is close to the melting point or is at a high temperature for a long time, which is greatly limited in the use environment at a high temperature; therefore, the development of high-temperature-resistant polyester is highly concerned. On the other hand, traditional polyester polymerization includes direct esterification method and ester exchange method, and these polymerization methods are usually carried out at high temperature, which has high energy consumption and generates by-products to reduce the reaction rate; this means that the polymerization of high-temperature-resistant polyester needs more stringent equipment and conditions.

[0003] Based on the above technical problems existing in the high-temperature-resistant polyester, it is necessary to regulate the chemical structure of the existing polyester film to develop a new type of high-temperature-resistant transparent polyester film, which can simultaneously improve the thermal and optical properties while maintaining the high performance of the polyester film material. SUMMARY

[0004] The purpose of the present application is to provide a diamine monomer for preparing high-temperature-resistant polyester-imide, which introduces imide bonds into polyester to form polyester-imide to solve the performance defects of existing polyester materials.

[0005] The purpose of the present application is to provide a polyester-imide prepared by using a diamine monomer and a preparation method thereof.

[0006] The purpose of the present application is to provide a high-temperature-resistant polyester-imide film and a preparation method thereof, which can improve the thermal and optical properties while maintaining the processability of the polyester film material.

[0007] The purpose of the present application is to provide an application of the high-temperature-resistant polyester-imide film.

[0008] To this end, the technical solution of the present application is as follows:

[0009] A diamine monomer for preparing high-temperature-resistant polyester-imide, which has the following chemical structure:

[0010]

[0011] In the formula, X is selected from one of the following: In the formula, X is selected from one of the following: In particular, n is 2, 3, 4, 5 or 6.

[0012] The diamine monomer is prepared by introducing an ester group with a symmetrical structure into the chemical structure of the diamine monomer, so as to prepare a novel polyester imide after reacting the diamine monomer with a new structure with an anhydride and through imidization. The novel polyester imide is based on a diamine monomer with a shorter aliphatic chain but a larger molecular chain rigidity, and can exhibit higher thermal stability. In addition, the novel polyester imide only contains benzene rings, so that the chemical structure is more stable, and finally exhibits higher thermal stability and higher residual mass at 800°C.

[0013] The diamine monomer for preparing the high-temperature-resistant polyester imide has the following two preparation methods according to the selection of X in the chemical structure thereof.

[0014] I. When X in the chemical structure of the diamine monomer is The preparation steps are as follows:

[0015] 1) A round-bottom flask is added with 4-aminobenzoic acid, a secondary primary alcohol, a catalyst and a solvent, and is equipped with a water separator and a reflux condenser. The water separator is pre-filled with the solvent for receiving water generated in the reaction. Under nitrogen stirring, the reaction system is slowly heated to 80-120°C, and refluxed for 4-8h. During the reflux process, the water layer in the water separator is discharged at regular time intervals to promote the forward esterification.

[0016] 2) The reaction product is cooled to room temperature, and the solvent is recovered by reduced pressure distillation. The remaining crude product is added with an appropriate amount of water, and slowly neutralized to pH≈7-8 by adding a 5wt%-10wt% sodium carbonate aqueous solution dropwise. The solid is filtered out, and washed with a small amount of cold water to remove inorganic salts and dried. The obtained crude product is dissolved in hot ethanol and filtered while hot. The filtrate is slowly cooled to crystallize, and placed in a vacuum dryer at 60°C after suction filtration to obtain the diamine monomer.

[0017] Preferably, in the above step 1), the molar ratio of 4-aminobenzoic acid to the secondary primary alcohol is 2:1. The solvent is toluene, and the amount of toluene added is 0.8-1.6 times the weight of 4-aminobenzoic acid. The catalyst is p-toluenesulfonic acid, and the amount of p-toluenesulfonic acid added is 3wt% of the solvent.

[0018] II. When X in the chemical structure of the diamine monomer is a phenolic compound containing The preparation steps are as follows:

[0019] 1) 4-nitrobenzoyl chloride is dissolved in a solvent to prepare a 4-nitrobenzoyl chloride solution with a mass fraction of 15wt%-25wt%;

[0020] 2) In a separate sealed flask, dissolve the phenolic compound in a solvent to obtain a phenolic compound solution with a mass fraction of 15wt% to 20wt%; the phenolic compound solution also contains a HCl absorbent;

[0021] The phenolic compound is:

[0022] 3) Slowly add the phenolic compound solution into the 4-nitrobenzoyl chloride solution cooled at 0°C using a syringe, and then stir the reaction mixture at room temperature; collect the precipitate of the reaction product by filtration, and wash with a small amount of tetrahydrofuran and a large amount of water, and then dry at 100°C to 120°C under vacuum for 8h to 10h to obtain a dinitro compound;

[0023] 4) Dissolve the dinitro compound in a solvent, which can be but is not limited to N,N-dimethylformamide, under the catalysis of Pd / C; then reflux in a hydrogen atmosphere at 100°C to 140°C, and monitor the completion of the catalytic reduction by thin layer chromatography; after removing the catalyst residue by hot filtration, concentrate the filtrate by an evaporator, wash the obtained precipitate with THF, and dry at 160°C to 180°C under vacuum for 12h to 18h to obtain a crude product; recrystallize the crude product from 1,4-dioxane, collect by filtration, and dry at 140°C to 160°C under vacuum for 12h to obtain a diamine monomer.

[0024] Preferably, in the above-mentioned steps 1) and 2), the solvent is anhydrous tetrahydrofuran; and the molar amount of 4-nitrobenzoyl chloride in step 1) is 2 times the molar amount of the phenolic compound in step 2).

[0025] Preferably, in the above-mentioned step 2), the HCl absorbent is pyridine, which is added in an amount of 2 to 3 times the molar amount of 4-nitrobenzoyl chloride and is dissolved in the phenolic compound solution by stirring.

[0026] A polyester imide prepared from the above-mentioned diamine monomer, which is prepared from the reaction of the above-mentioned diamine monomer and an acid anhydride, has a chemical structure as follows:

[0027]

[0028] The phenolic compound is:

[0029] X is selected from one of In , n is 2, 3, 4, 5, or 6;

[0030] Y is selected from:

[0031] The value of m ranges from 50 to 200.

[0032] A transparent high-temperature-resistant polyester imide film is prepared from the polyester imide.

[0033] The preparation method of the high-temperature-resistant polyester imide film includes the following steps:

[0034] S1, dissolving diamine monomers in an organic solvent, adding anhydride in batches under nitrogen atmosphere and ice bath environment, and supplementing solvent to the reaction solution during the reaction to adjust the solid content of the solution to 20wt%-30wt%, and preparing a polyamic acid ester solution after 18h-24h of reaction; wherein the molar ratio of the diamine monomers to the anhydride is 1:(1-1.01);

[0035] S2, placing the polyamic acid ester solution in a negative pressure environment to remove bubbles, and then pouring the polyamic acid ester solution on a clean and dry glass substrate, using a spiral fine adjustment film applicator to cooperate with an automatic film applicator to scrape and coat a controllable-thickness polyamic acid ester wet film, and performing a pre-baking process to prepare a polyamic acid ester film;

[0036] S3, high-temperature firing the polyamic acid ester film after the pre-baking treatment to obtain a high-temperature-resistant transparent polyester film.

[0037] Preferably, in step S1, the organic solvent is N,N-dimethylacetamide, and the amount of addition is 3-4 times that of the diamine monomers.

[0038] Preferably, in step S2, the negative pressure bubble removal operation is: placing the polyamic acid ester solution in a vacuum drying box, and vacuumizing for 2h-24h at room temperature to ensure that the bubbles in the solution are completely removed.

[0039] Preferably, the specific steps of forming a polyamic acid ester wet film by coating a film are: first pouring the polyamic acid ester solution on a clean and dry glass substrate and standing for 10s-30s, and then using a spiral fine adjustment film applicator to cooperate with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10mm / s-20mm / s, so as to obtain a polyamic acid ester film with a specified thickness and a flat and defect-free surface.

[0040] Preferably, the specific steps of the pre-baking operation are: placing the glass substrate with the polyamic acid ester wet film formed thereon in a vacuum oven, heating at 60℃-100℃ for 2h-8h for pre-baking and drying, at this time, most of the solvent in the polyamic acid ester wet film formed by coating a film has been removed.

[0041] Preferably, the high-temperature sintering operation step is: under a nitrogen atmosphere, heating from room temperature (generally 20-25℃) to 250-300℃ at a rate of 2-5℃ / min, and maintaining at 100℃, 200℃, and the highest temperature (i.e. 250-300℃) for 1h each; and then naturally cooling to room temperature to prepare the polyester-imide film.

[0042] In some embodiments, the number average molecular weight of the high-temperature resistant polyester-imide film of the present application is 4.0×10 4 g / mol-1.0×10 5 g / mol.

[0043] The transparent high-temperature resistant polyester-imide film can be used in any one or more of the following film structures: high-temperature resistant optical film, flexible circuit substrate, lithium battery separator coating, and optoelectronic chip substrate.

[0044] Compared with the prior art, the diamine monomer for preparing the high-temperature resistant polyester-imide of the present application is modified in chemical structure, so as to simultaneously contain imide bonds and ester bonds in the polyester-imide synthesized from the diamine monomer and an acid anhydride; the high-temperature resistant polyester-imide film prepared based on the diamine monomer not only has a simple preparation method, but also has excellent optical performance, thermal performance and flexibility; the polyester-imide film has a high optical transmittance and a high glass transition temperature, so as to have good heat resistance and thermal stability, and thus has good application prospects in the fields of high-temperature resistant optical film, flexible circuit substrate, lithium battery separator coating, and optoelectronic chip substrate. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 A comparison chart of the thermogravimetric curves of the polyester films prepared in Examples 1-2 of the present application and the commercialized polyethylene terephthalate film of Comparative Example 1;

[0046] Figure 2 A comparison chart of the differential scanning calorimetric analysis curves of the polyester films prepared in Examples 1-2 of the present application and the commercialized polyethylene terephthalate film of Comparative Example 1;

[0047] Figure 3 A comparison chart of the ultraviolet-visible spectrograms of the polyester films prepared in Examples 1-2 of the present application and the commercialized polyethylene terephthalate film of Comparative Example 1. DETAILED DESCRIPTION

[0048] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments, but the following embodiments are by no means limiting to the present application.

[0049] Example 1

[0050] In a round bottom flask, 4-aminobenzoic acid (0.2 mol), ethylene glycol (0.1 mol), toluene (30 mL) and p-toluenesulfonic acid (3 wt% of toluene) were sequentially added, a water separator and reflux condenser were installed, and the water separator was pre-filled with toluene for receiving the water generated in the reaction; under nitrogen stirring, the reaction system was slowly heated to 80°C, and refluxed for 4 h; during the reaction, the generated water was azeotroped with toluene, and condensed and separated in the water separator (water in the lower layer), and the water layer was released at regular intervals to promote the forward progress of esterification; after the reaction was completed, the reaction product was cooled to room temperature, and toluene was recovered by distillation under reduced pressure, the remaining crude product was added with an appropriate amount of water and slowly neutralized to pH ≈ 7-8 by adding 5 wt% sodium carbonate aqueous solution dropwise; the precipitated solid was filtered, and the inorganic salts in the solid were washed away with a small amount of cold water, and the crude product was dried to obtain a crude product, which was dissolved in hot ethanol and filtered while hot, the filtrate was slowly cooled to crystallize, and white crystals were obtained by suction filtration and placed in a vacuum oven at 60°C to obtain monomeric ethane-1,2-diyl bis(4-aminobenzoate).

[0051] The chemical structural formula of the ethane-1,2-diyl bis(4-aminobenzoate) is as follows:

[0052]

[0053] In a flask reaction vessel equipped with mechanical stirring and a nitrogen atmosphere, ethane-1,2-diyl bis(4-aminobenzoate) (0.6006 g, 2.00 mmol) was dissolved in 2.5 mL of N,N-dimethylacetamide and continuously stirred, and after complete dissolution, hexafluoro dianhydride (0.8974 g, 2.02 mmol) was added in multiple batches to the reaction solution, and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, and during the process, N,N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 30 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumed for 2 h to remove bubbles in the solution.

[0054] The polyamic acid ester solution was poured on a clean glass substrate and left for 20 s; after the polyamic acid ester solution stopped flowing, a spiral micro-adjustment film applicator was used in cooperation with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the film-coated substrate was placed in a vacuum oven, and slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, to obtain a 25 μm thick polyamic acid ester film; then the polyamic acid ester film was high-temperature fired according to the following procedure: under a nitrogen atmosphere, the temperature was raised from 20°C to 300°C at a rate of 2°C / min, and held at 100°C, 200°C, and 300°C for 1 h each time; finally, the high-temperature fired film was naturally cooled to room temperature, and a polyester imide film was prepared. The number average molecular weight of the polyester imide was tested to be 6.4 x 10 4 g / mol.

[0055] The chemical structural formula of the polyester imide film is as follows:

[0056]

[0057] Example 2

[0058] A round-bottom flask was sequentially charged with 4-aminobenzoic acid (0.2 mol), 1,5-pentanediol (0.1 mol), toluene (50 mL), and p-toluenesulfonic acid (3 wt% of toluene), a water separator and a reflux condenser were installed, and the water separator was pre-filled with toluene for receiving water generated in the reaction; under nitrogen stirring, the reaction system was slowly heated to 90°C, and refluxed for 6 h; during the reaction, the generated water was azeotroped with toluene, and condensed and separated in the water separator (water in the lower layer), and the water layer was discharged at regular intervals to promote the forward progress of esterification; after the reaction was completed, the reaction product was cooled to room temperature, and toluene was recovered by distillation under reduced pressure, and the remaining crude product was added with an appropriate amount of water and slowly neutralized to pH ≈ 7-8 by dropwise addition of a 5 wt% aqueous sodium carbonate solution; the precipitated solid was filtered, and the inorganic salts in the solid were washed away with a small amount of cold water, and the crude product was dried to obtain a monomer pentane-1,5-diyl bis(4-aminobenzoate).

[0059] The chemical structural formula of the pentane-1,5-diyl bis(4-aminobenzoate) is as follows:

[0060]

[0061] In a flask reaction vessel equipped with mechanical stirring and nitrogen atmosphere, pentane-1, 5-diyl bis (4-aminobenzoate) (0.6848 g, 2.00 mmol) was dissolved in 2.5 mL of N, N-dimethylacetamide and continuously stirred, after complete dissolution, hexafluorodianhydride (0.8974 g, 2.02 mmol) was added to the reaction solution in batches, and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, during which N, N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 23 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumized for 2 h to remove bubbles in the solution.

[0062] The polyamic acid ester solution was poured onto a clean glass substrate and left to stand for 20 s; after the polyamic acid ester solution stopped flowing, a spiral fine adjustment film applicator was used in cooperation with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the film-coated substrate was placed in a vacuum oven and slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, obtaining a 25 μm thick polyamic acid ester film; then the polyamic acid ester film was high-temperature fired according to the following program: under nitrogen atmosphere, heating from 20°C to 250°C at a rate of 2°C / min, and holding at 100°C, 200°C, 250°C for 1 h respectively; finally, the high-temperature fired film was naturally cooled to room temperature, and a polyester imide film was prepared. It was tested that the number average molecular weight of the polyester imide was 4.7 x 10 4 g / mol.

[0063] The chemical structural formula of the polyester imide film is as follows:

[0064]

[0065] Example 3

[0066] In a round bottom flask, 4-aminobenzoic acid (0.2 mol), 1,6-hexanediol (0.1 mol), toluene (50 mL) and p-toluenesulfonic acid (3 wt% of toluene) were sequentially added, a water separator and a reflux condenser were installed, and the water separator was pre-filled with toluene for receiving the water generated in the reaction; under nitrogen stirring, the reaction system was slowly heated to 100°C, and refluxed for 8 h; during the reaction, the generated water was azeotroped with toluene, and condensed and separated in the water separator (water in the lower layer), and the water layer was released at regular intervals to promote the forward progress of esterification; after the reaction was completed, the reaction product was cooled to room temperature, and toluene was recovered by distillation under reduced pressure, the remaining crude product was added with an appropriate amount of water and slowly neutralized to pH ≈ 7-8 by adding 5 wt% sodium carbonate aqueous solution dropwise; the precipitated solid was filtered, and the inorganic salts in the solid were washed away with a small amount of cold water, and the crude product was dried to obtain a crude product, which was dissolved in hot ethanol and filtered while hot, the filtrate was slowly cooled to crystallize, and white crystals were obtained by suction filtration, and were placed in a vacuum dryer at 60°C to obtain monomeric hexane-1,6-diyl bis(4-aminobenzoate).

[0067] The chemical structural formula of the hexane-1,6-diyl bis(4-aminobenzoate) is as follows:

[0068]

[0069] In a flask reaction vessel equipped with mechanical stirring and a nitrogen atmosphere, hexane-1,6-diyl bis(4-aminobenzoate) (0.7128 g, 2.00 mmol) was dissolved in 2.5 mL of N,N-dimethylacetamide and continuously stirred, after complete dissolution, hexafluorodianhydride (0.8974 g, 2.02 mmol) was added in multiple batches to the reaction solution, and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, and during the process, N,N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 23 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumed for 2 h to remove bubbles in the solution.

[0070] The polyamic acid ester solution was poured onto a clean glass substrate and left for 20 s; after the polyamic acid ester solution stopped flowing, a spiral fine-tuning film applicator was used in cooperation with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the substrate with the completed film was placed in a vacuum oven, slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, to obtain a 25 pm thick polyamic acid ester film; then the polyamic acid ester film was high-temperature baked according to the following program: under a nitrogen atmosphere, heated from 20°C to 250°C at a rate of 2°C / min, and kept at 100°C, 200°C, and 250°C for 1 h respectively; finally, the completed film after high-temperature baking was naturally cooled to room temperature to obtain a polyester imide film. It was tested that the number average molecular weight of the polyester imide was 4.5 x 10 4 g / mol.

[0071] The chemical structural formula of the polyester imide film is as follows:

[0072]

[0073] Example 4

[0074] In a flask reaction vessel equipped with mechanical stirring and a nitrogen atmosphere, ethane-1, 2-diyl bis(4-aminobenzoate) (0.6006 g, 2.00 mmol) was dissolved in 2.5 mL of N,N-dimethylacetamide and continuously stirred, after complete dissolution, the reaction solution was added in batches with pyromellitic dianhydride (0.4406 g, 2.02 mmol), and continuously stirred under ice water bath conditions for 22 h until the system showed a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, during which N,N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 30 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumed for 2 h to remove bubbles in the solution.

[0075] The polyamic acid ester solution was poured onto a clean glass substrate and left for 20 s; after the polyamic acid ester solution stopped flowing, a spiral fine-tuning film applicator was used in cooperation with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the substrate with the completed film was placed in a vacuum oven, slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, to obtain a 25 pm thick polyamic acid ester film; then the polyamic acid ester film was high-temperature baked according to the following program: under a nitrogen atmosphere, heated from 20°C to 250°C at a rate of 2°C / min, and kept at 100°C, 200°C, and 250°C for 1 h respectively; finally, the completed film after high-temperature baking was naturally cooled to room temperature to obtain a polyester imide film. It was tested that the number average molecular weight of the polyester imide was 4.5 x 104 g / mol.

[0076] The chemical structure of the polyester imide film is shown below:

[0077]

[0078] Example 5

[0079] In a flask reaction vessel equipped with mechanical stirring and nitrogen atmosphere, pentane-1, 5-diyl bis (4-aminobenzoate) (0.6848 g, 2.00 mmol) was dissolved in 2.5 mL of N, N-dimethylacetamide and continuously stirred, after complete dissolution, pyromellitic dianhydride (0.4406 g, 2.02 mmol) was added to the reaction solution in batches, and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, during which N, N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 30 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumed for 2 h to remove bubbles in the solution.

[0080] The polyamic acid ester solution was poured onto a clean glass substrate and left to stand for 20 s; after the polyamic acid ester solution stopped flowing, a spiral fine adjustment film applicator was used in combination with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the film-coated substrate was placed in a vacuum oven and slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, obtaining a 25 μm thick polyamic acid ester film; then the polyamic acid ester film was subjected to high temperature firing according to the following program: under nitrogen atmosphere, heating from 20°C to 250°C at a rate of 2°C / min, and holding at 100°C, 200°C, 250°C for 1 h respectively; finally, the film after high temperature firing was naturally cooled to room temperature, and a polyester imide film was prepared. The number average molecular weight of the polyester imide was tested to be 4.5 x 10 4 g / mol.

[0081] The chemical structure of the polyester imide film is shown below:

[0082]

[0083] Example 6

[0084] In a flask reaction vessel equipped with mechanical stirring and nitrogen atmosphere, hexane-1, 6-diyl bis (4-aminobenzoate) (0.7128 g, 2.00 mmol) was dissolved in 2.5 mL of N,N-dimethylacetamide and continuously stirred, after complete dissolution, pyromellitic dianhydride (0.4406 g, 2.02 mmol) was added to the reaction solution in batches, and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, during which N,N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 23 wt%; after the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven and vacuumized for 2 h to remove bubbles in the solution.

[0085] The polyamic acid ester solution was poured onto a clean glass substrate and left to stand for 20 s; after the polyamic acid ester solution stopped flowing, a spiral fine adjustment film applicator was used in cooperation with an automatic film applicator to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s; then, the film-coated substrate was placed in a vacuum oven and slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, to obtain a 25-μm-thick polyamic acid ester film; then the polyamic acid ester film was high-temperature fired according to the following program: under a nitrogen atmosphere, heated from 20°C to 250°C at a rate of 2°C / min, and kept at 100°C, 200°C, and 250°C for 1 h respectively; finally, the high-temperature fired film was naturally cooled to room temperature to obtain a polyester-imide film. It was tested that the number average molecular weight of the polyester-imide was 4.3 x 10 4 g / mol.

[0086] The chemical structural formula of the polyester-imide film is as follows:

[0087]

[0088] Example 7

[0089] To a flask was added 4-nitrobenzoyl chloride (4-NBC, 20 mmol) dissolved in anhydrous tetrahydrofuran (THF, 16.7 mL) to give a 4-NBC solution; in a separate, sealed flask, hydroquinone (HQ, 10 mmol) was dissolved in THF (6.3 mL) and pyridine (60 mmol, 4.9 mL) was added as a sink for the HCl evolved from the acyl chloride to give a HQ solution; to the 4-NBC solution cooled at 0 °C, the HQ solution was added slowly using a syringe, and the reaction mixture was then stirred at room temperature for 12 h, after which the precipitate of the reaction product was collected by filtration and washed with a small amount of THF and a large amount of water, and then dried under vacuum at 100 °C for 8 h to give the dinitro compound; next, the dinitro compound (4.56 mmol) was dissolved in N,N-dimethylformamide (DMF, 30 mL) in the presence of Pd / C (0.067 g) as a catalyst, and the reaction mixture was refluxed under a hydrogen atmosphere at 100 °C for 5 h, the completion of the catalytic reduction being monitored by thin layer chromatography, after which the catalyst residue was removed by hot filtration, the filtrate was concentrated on an evaporator, and the resulting precipitate was washed with THF and dried under vacuum at 160 °C for 12 h; the resulting crude product was recrystallized from 1,4-dioxane, collected by filtration, and dried under vacuum at 140 °C for 12 h to give [4-(4-aminobenzoyl)oxyphenyl] 4-aminobenzoate.

[0090] The chemical structure of this [4-(4-aminobenzoyl)oxyphenyl] 4-aminobenzoate is:

[0091]

[0092] In a flask reaction vessel equipped with mechanical stirring and nitrogen atmosphere, [4-(4-aminobenzoyl)oxyphenyl] 4-aminobenzoate (0.6967 g, 2.00 mmol) was dissolved in 2.5 mL of N,N-dimethylacetamide and continuously stirred, after complete dissolution, hexafluorodianhydride (0.8974 g, 2.02 mmol) was added to the reaction solution in batches and continuously stirred under ice water bath conditions for 22 h until the system presented a stable transparent viscous solution, which was an intermediate polyamic acid ester solution, during which N,N-dimethylacetamide was supplemented to the reaction solution to adjust the solid content of the solution to 30 wt%. After the reaction was completed, the polyamic acid ester solution was placed in a vacuum oven, vacuum was applied for 2 h to remove bubbles in the solution. Then the polymer solution was poured onto a clean glass substrate, and a spiral micro-adjustment film applicator was used to uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10 mm / s using an automatic film applicator. Then the film was placed in a vacuum oven and slowly heated from room temperature to 80°C, and continued to pre-bake for 2 h to remove most of the solvent, obtaining a 25 μm thick polyamic acid ester film. Then the polyamic acid ester film was subjected to high temperature firing according to the following program: under nitrogen atmosphere, the temperature was raised from 20°C to 300°C at a rate of 2°C / min, and held at 100°C, 200°C, and 300°C for 1 h respectively, and then naturally cooled to room temperature, finally obtaining a polyester-imide film.

[0093] The number average molecular weight of the polyester-imide was tested to be 4.4 x 10 4 g / mol.

[0094] The chemical structure of the polyester-imide film is shown below:

[0095]

[0096] Comparative Example 1

[0097] A commercially available polyethylene terephthalate film with a thickness of 25 μm was produced by Zhejiang Sain Package Co., Ltd.

[0098] Performance test:

[0099] (I) Thermal gravimetric analysis and differential scanning calorimetric analysis of the polyester film:

[0100] The thermal decomposition temperature of the polyester-imide films prepared in Examples 1-7 and the commercially available polyethylene terephthalate film was tested using a thermal gravimetric analyzer, the experimental determination conditions were: under nitrogen atmosphere, the temperature was raised from 40°C to 800°C at a rate of 10°C / min, the mass of the sample was 5 mg, and the temperatures at which 5% and 10% of thermal weight loss occurred were recorded as T d5％ and T d10％ .

[0101] The glass transition temperature (Tg) of the polyester imide films prepared in Examples 1-7 and the commercially available polyethylene terephthalate film was tested by differential scanning calorimetry analysis, with the following test conditions: sample mass 5-10 mg, nitrogen atmosphere, nitrogen flow rate 50 mL / min, temperature increase rate 20 °C / min from room temperature to 400 °C, holding for 5 min, temperature decrease to 40 °C, temperature increase rate 10 °C / min from 40 °C to 400 °C, nitrogen flow rate 50 mL / min, and second temperature increase curve measurement of the Tg of the polymer. g g

[0102] The specific test results are shown in Table 1 below.

[0103] Table 1:

[0104] Test Example T g (°C) T d5％ (°C) R w800 (%)]] Example 1 240 436.4 45.0 Example 2 172 407.3 40.4 Example 3 162 402.6 38.2 Example 4 280 468.9 51.2 Example 5 211 422.1 49.6 Example 6 203 411.5 45.2 Example 7 280 455 45.3 Comparative Example 1 76 398.6 13.5

[0105] As can be seen from Table 1, the polyester imide films of Examples 1-7 exhibit excellent thermal properties in the above tests; specifically, the glass transition temperature of the polyester imide films ranges from 162 °C to 280 °C, the temperature at which 5% of the thermal weight loss ranges from 402.6 °C to 468.9 °C, and the residual mass percentage at 800 °C ranges from 38.2% to 51.2%; while the commercially available polyethylene terephthalate film of Comparative Example 1 has a glass transition temperature of only 76 °C, a 5% thermal weight loss temperature of 398.6 °C, and a residual mass percentage at 800 °C of only 13.5%.

[0106] As can be seen from the above thermal analysis test results, the polyester imide films prepared by the method of the present application are significantly superior to polyethylene terephthalate films in terms of thermal properties, because the polyester imide films prepared by the method of the present application contain imide structures linked to benzene rings, forming a highly conjugated and planar rigid structure, and in addition, the ester groups are directly connected to the benzene rings, forming a conjugated system, with rigidity much higher than the benzene rings in polyethylene terephthalate, limiting chain segment movement; while the flexibility of the ester bonds and the ethylene glycol segments in polyethylene terephthalate reduce the interchain forces, resulting in higher bond energy of the imide ring than the ester bond, requiring a higher temperature for decomposition, and thus better high temperature resistance than polyethylene terephthalate.

[0107] ​​Take Example 1 and Example 2 as examples for specific analysis. Example 1 has better thermal performance than Example 2, because the short spacer group (-(CH2)2) in Example 1 severely limits the internal rotation freedom of the C-C bond, and cannot effectively decouple the rigid structural units composed of ester group-phenyl ring-imide ring on both sides, the whole molecular chain is relatively rigid, and the segment movement needs to overcome a higher energy barrier, so the glass transition temperature is higher. The long spacer group (-(CH2)5) in Example 2 can effectively isolate and decouple the rigid units at both ends, greatly reducing the rigidity of the molecular chain, and the glass transition temperature is lower. The rigid molecular chain of Example 1 is more difficult to twist and deform when heated, and a higher temperature is required to break the chemical bond to initiate decomposition, so the thermal decomposition temperature of Example 1 is higher. It can be seen that the polyester-imide film of the application can beneficially adjust its thermal performance according to the needs of the application scenario.

[0108] As shown in Figure 1 is a comparison diagram of the thermal gravimetric curves of the polyester-imide films prepared in Example 1 and Example 2, and the commercially available polyethylene terephthalate; as shown in Figure 2 is a comparison diagram of the differential scanning calorimetric analysis curves of the polyester-imide films prepared in Example 1 and Example 2, and the commercially available polyethylene terephthalate.

[0109] (II) Optical performance test:

[0110] The optical transmittance of the polyester-imide films prepared in Example 1 to Example 7, and the commercially available polyethylene terephthalate film was tested by using an ultraviolet-visible spectrophotometer under the condition of 200nm-800nm range and resolution of 0.5nm.

[0111] The specific test results are shown in Table 2 below.

[0112] Table 2:

[0113] Test Example T 450 (%)]] T 500 (%)]] Example 1 80.6 83.7 Example 2 83.1 86.1 Example 3 84.2 88.5 Example 4 79.6 80.6 Example 5 81.5 82.4 Example 6 83.3 83.9 Example 7 76.9 80.0 Comparative Example 1 84.2 84.7

[0114] As shown in Figure 3 is a comparison diagram of the ultraviolet-visible spectrum curves of the polyester-imide films prepared in Example 1 to Example 7 and the commercially available polyethylene terephthalate film. According to the optical analysis side view results in Table 3, the optical transmittance of the polyester-imide films prepared by the method of the application at 450nm is 80.6% and 83.1%, and the optical transmittance at 500nm is 83.7% and 86.1%, indicating that the film has good optical transparency, and compared with the polyethylene terephthalate film, the optical transmittance of Example 2 at 500nm is more than 85%.

[0115] In addition, by comparing Examples 1-3 and comparing Examples 4-6, it can be found that in the polyester imide designed in the present application, the optical performance of the polyester imide can be effectively regulated by adjusting the length of the carbon chain. However, too long main chain will lead to the decrease of the thermal stability of the polymer. In the process of adjusting the main chain structure of the polymer, considering the thermal stability and the light transmission performance of the polymer, Example 1 shows better performance characterization effect, that is, when X is selected in the diamine monomer When n=2 corresponds to the performance effect of the prepared polyester imide is better, and in the case of the same selection of diamine monomer, the selection of anhydride containing double trifluoromethyl structure is more conducive to better performance.

[0116] In summary, the polyester imide film of the present application has excellent thermal and optical properties, and its excellent high temperature resistance makes it can be used as a high temperature resistant optical film, which can improve the thermal stability of the diaphragm; due to the existence of ester group and imide bond, the polyester imide film also has good flexibility, which can be used in flexible circuit substrate, lithium battery diaphragm coating to improve the thermal stability of the diaphragm; similarly, the polyester imide film is suitable for harsh environments such as optoelectronic chip packaging, and the polyester maintains mechanical strength at high temperature, which is expected to be used as aerospace components.

[0117] The above is only the preferred embodiment of the present application, and is not intended to limit the other forms of the present application. Any skilled person in the art can use the disclosed technical content to make changes or modifications to equivalent embodiments. However, any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments, which does not deviate from the technical solution content of the present application, still belongs to the protection scope of the technical solution of the present application.

Claims

1. A diamine monomer for preparing transparent, high-temperature resistant polyesterimide films, characterized in that, The chemical structure is: wherein X is selected from one of the following: wherein, in wherein n is 2, 3, 4, 5 or 6.

2. The diamine monomer of claim 1, wherein, When X in the chemical structure of the diamine monomer is The preparation steps are: 1) Add 4-aminobenzoic acid, primary diol, catalyst and solvent into a round bottom flask, and install a water separator and reflux condenser, the water separator is filled with solvent in advance to receive water generated in the reaction; under nitrogen stirring, the reaction system is slowly heated to 80-120℃, and refluxed for 4-8h, during the reflux, the water layer in the water separator is discharged at regular intervals to promote the forward esterification; 2) Cool the reaction product to room temperature, and recover the solvent by distillation under reduced pressure, add water to the remaining crude product, and slowly neutralize to pH≈7-8 by adding 5wt%-10wt% sodium carbonate solution; filter the precipitated solid, wash with a small amount of cold water, dry, and then recrystallize with hot ethanol, and obtain the diamine monomer by filtration and drying.

3. The diamine monomer of claim 1, wherein, When X in the chemical structure of the diamine monomer is a phenolic compound comprising the preparation steps are as follows: 1) Dissolve 4-nitrobenzoyl chloride in a solvent to prepare a 4-nitrobenzoyl chloride solution with a mass fraction of 15wt%-25wt%; 2) Dissolve the phenolic compound in a solvent to obtain a phenolic compound solution with a mass fraction of 15wt%-20wt%; The phenolic compound solution contains HCl absorbent; 3) Slowly add the phenolic compound solution to the 4-nitrobenzoyl chloride solution cooled at 0℃, and then stir the reaction mixture at room temperature for 4-8h, and obtain the dinitro compound by filtering, washing and drying the precipitate generated in the reaction; 4) Dissolve the dinitro compound in a solvent under the catalysis of Pd / C, and reflux in a hydrogen atmosphere at 100-140℃, and obtain the diamine monomer by hot filtration and concentration of the filtrate after monitoring the completion of the catalytic reduction by thin layer chromatography, and washing, drying, recrystallizing in 1,4-dioxane, filtering and vacuum drying again.

4. A polyester imide prepared from the diamine monomer of any one of claims 1-3 and an acid anhydride, and the chemical structure is: wherein, X is selected from One of the following, wherein, in n is 2, 3, 4, 5 or 6; Y is selected from: m is in the range of 50 to 200.

5. A transparent high temperature resistant polyester imide film, characterized by, The polyester imide is prepared by using the polyester imide of claim 4.

6. A process for producing the transparent high-temperature-resistant polyester imide film according to claim 5, characterized by, The steps are as follows: S1, dissolve the diamine monomer in an organic solvent, add the acid anhydride in batches under nitrogen atmosphere and ice bath environment, and supplement the solvent to the reaction product during the reaction to adjust the solid content of the solution to 20wt%-30wt%, and obtain the polyamic acid ester solution by reacting for 18-24h; S2, pour the defoamed polyamic acid ester solution onto a clean and dry glass substrate, and scrape to form a polyamic acid ester wet film with a specified thickness, and obtain the polyamic acid ester film by pre-baking; S3, under nitrogen atmosphere, heat the polyamic acid ester film from room temperature to 250-300℃ at a rate of 2℃ / min, and keep at 100℃, 200℃ and the highest temperature atmosphere respectively for 1h; and then naturally cool to room temperature to obtain the polyester imide film.

7. The method for preparing the transparent high-temperature resistant polyesterimide film according to claim 6, characterized in that, In step S1, the organic solvent is N,N-dimethylacetamide, and the amount is 3-4 times of the diamine monomer.

8. The method for preparing the transparent high-temperature resistant polyesterimide film according to claim 6, characterized in that, In step S2, the specific steps for forming the polyamic acid ester wet film are: first, pour the polyamic acid ester solution onto a clean and dry glass substrate and stand for 10-30 seconds; after the polyamic acid ester solution stops flowing, uniformly cover the polyamic acid ester solution on the surface of the substrate at a speed of 10-20 mm / s.

9. Use of the transparent high-temperature-resistant polyester imide film according to claim 5, characterized in that, For high-temperature-resistant optical films, flexible circuit substrates, lithium battery separator coatings, or optoelectronic chip substrates.

Images