Polyimide precursor solution and preparation method and application thereof
By introducing symmetrical dianhydrides containing ester groups and long fat chains, the viscosity of the polymerization reaction system is reduced, and the problem of high viscosity of the traditional polyimide precursor solution is solved, and a high solid content and low viscosity polyimide precursor solution is realized, which improves the performance of the film material.
Patent Information
- Application Number
- CN202411829827.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-04-04
AI Technical Summary
The traditional polyimide precursor solution has a high viscosity, is difficult to process, and it is difficult to obtain a film of uniform thickness under high solid content.
The introduction of symmetrical dianhydride containing ester groups and long fat chains as dianhydride monomers reduces the reactivity of the monomers, hinders the polymerization between molecules, and effectively reduces the viscosity of the polymerization reaction system.
Under the premise of high solid content, a low viscosity polyimide precursor solution was obtained, which improved the leveling and operability of the polyamic acid slurry, and the formed film material had excellent performance, uniform film thickness, smoothness and transparency.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of polymer materials, and in particular to a polyimide precursor solution and a preparation method and application thereof. Background Art
[0002] Polyimide (PI) is widely used in electronics, aerospace, automotive industry, medical devices and food packaging due to its good flexibility and electrical insulation.
[0003] At present, the most common method to obtain polyimide is to synthesize polyamic acid (PAA) by thermal imidization or chemical imidization. Polyamic acid solution is usually synthesized by dianhydride and diamine in a non-protonic polar solvent, such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and other solvents at low temperature (-10℃~25℃) or room temperature (25~40℃).
[0004] The viscosity of the polyimide precursor solution is mainly determined by the solid content and relative molecular mass of the system. The polyimide precursor solution prepared by traditional technology generally has a high relative molecular mass, so the viscosity is also high, which is not easy to process and it is difficult to obtain a film of uniform thickness subsequently; while reducing the solid content will lead to a decrease in the thickness of the slurry film, which is not conducive to applications with high solid content and low viscosity. Summary of the invention
[0005] Based on this, it is necessary to provide a polyimide precursor solution and a preparation method and application thereof, so as to reduce the viscosity of the polyamic acid slurry under the premise of high solid content.
[0006] In one aspect of the present application, a polyimide precursor solution is provided, wherein the polyimide precursor solution comprises a polyimide precursor, wherein the raw materials for preparing the polyimide precursor comprise a diamine monomer and a dianhydride monomer; the diamine monomer comprises an aromatic diamine, and the dianhydride monomer comprises a symmetrical dianhydride represented by formula (1);
[0007] (1),
[0008] Among them, n=m, 2≤m≤8, 2≤n≤8.
[0009] The monomers for preparing the above-mentioned polyimide precursor solution include diamine monomers and dianhydride monomers. The dianhydride monomer adopts the symmetrical dianhydride shown in formula (1), which contains an ester group and a long fatty chain. The obtained polyimide precursor solution has the characteristics of high solid content and low viscosity. The present application introduces the symmetrical dianhydride containing an ester group and a long fatty chain shown in formula (1) into the monomers for preparing the polyimide precursor solution, which reduces the reactivity of the monomer, hinders the polymerization between molecules, and effectively reduces the viscosity of the polymerization reaction system, so that the polyimide precursor solution has a high solid content and low viscosity. In addition, the polyimide precursor solution of the present application can be normally cast into a film, which improves the leveling and operability of the polyamic acid slurry. The subsequent formed film material has excellent performance, not only the film layer thickness is uniform, but also the smoothness and transparency are good.
[0010] The present application introduces a symmetrical dianhydride containing an ester group and a long fatty chain as shown in formula (1). During the dissolution process in the solvent, due to the certain polarity of the carbon-oxygen double bond and the carbon-oxygen single bond, dipole-dipole interactions or hydrogen bonds can be formed with the solvent molecules, thereby promoting the dissolution process, accelerating the dissolution rate, and improving the synthesis efficiency of polyamic acid.
[0011] In some embodiments, the polyimide precursor solution further comprises silica sol, and the silica sol dopes the diamine monomer and the dianhydride monomer to form polyamic acid.
[0012] In some embodiments, the mass content of the silica sol in the polyimide precursor solution is 1% to 5%.
[0013] In some of the embodiments, the symmetrical dianhydride is selected from at least one of trimellitic anhydride-1,4-benzenediethanol ester, trimellitic anhydride-1,4-benzenedipropanol ester, trimellitic anhydride-1,4-benzenedibutyl ester, trimellitic anhydride-1,4-benzenedipentanol ester, trimellitic anhydride-1,4-benzenedixanol ester, trimellitic anhydride-1,4-benzenedihexanol ester, and trimellitic anhydride-1,4-benzenedioctyl ester.
[0014] In some embodiments, the aromatic diamine is a rigid aromatic diamine.
[0015] In some embodiments, the aromatic diamine is selected from: 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl, 4,4'-diaminodiphenyl sulfone, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-[1,4-phenylbis(oxy)]bis(3-methylaniline), 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline], 2,2-bis[4-(4-aminophenoxy)benzene]hexafluoropropane, 4,4'-bis(4-aminophenoxy)benzophenone, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, and at least one of 2,5-bis(4-aminophenoxy)biphenyl.
[0016] In some embodiments, the molar ratio of the symmetrical dianhydride to the aromatic diamine is 1:0.97-1.2.
[0017] The second aspect of the present application provides a method for preparing the polyimide precursor solution as described in the first aspect, comprising the following steps:
[0018] The aromatic diamine and the symmetrical dianhydride are subjected to polymerization reaction in a solvent to obtain the precursor solution.
[0019] In some embodiments, after the polymerization reaction and before obtaining the precursor solution, the following step is further included: adding silica sol to the reaction solution obtained from the polymerization reaction and blending them to obtain a precursor solution doped with silica sol.
[0020] In some embodiments, before the polymerization reaction, the aromatic diamine is first dissolved in the solvent, and the symmetrical dianhydride is added after the aromatic diamine is dissolved, and the aromatic diamine dissolution satisfies at least one of the following conditions:
[0021] (1) heating the solvent to a temperature of 50°C to 100°C;
[0022] (2) The solvent is at least one selected from N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone and N,N-dimethylformamide.
[0023] In some embodiments, the polymerization reaction satisfies at least one of the following conditions:
[0024] (1) The polymerization reaction temperature is 65°C to 110°C;
[0025] (2) The polymerization reaction time is 5h~12h.
[0026] The third aspect of the present application provides a polyimide precursor solution, which is prepared by the preparation method described in the second aspect of the present application.
[0027] A fourth aspect of the present application provides a polyimide film, wherein the polyimide film is prepared by coating the polyimide precursor solution of the third aspect and then subjecting it to thermal imidization or chemical imidization; or
[0028] The monomers for preparing the polyimide film include diamine monomers and dianhydride monomers, wherein the diamine monomers include aromatic diamines, and the dianhydride monomers include symmetrical dianhydrides represented by formula (1);
[0029] (1),
[0030] Among them, n=m, 2≤m≤8, 2≤n≤8.
[0031] The fifth aspect of the present application provides a resin product comprising the polyimide film as described in the fourth aspect. DETAILED DESCRIPTION
[0032] The polyamic acid slurry of the present invention and its preparation method and application are further described in detail below in conjunction with specific examples. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.
[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.
[0034] The optional scope of the terms "and / or", "or / and", and "and / or" used in this article includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, said any and all combinations include any combination of any two related listed items, any more related listed items, or all related listed items.
[0035] As used herein, "at least one" means one, two or more than two.
[0036] In the present invention, "the first aspect", "the second aspect", "the third aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.
[0037] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.
[0038] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.
[0039] The term "aromatic diamine" refers to a diamine having two amino groups. And an organic compound with an aromatic ring structure.
[0040] The term "aromatic" refers to an aromatic hydrocarbon group derived by removing one or more hydrogen atoms from an aromatic ring compound.
[0041] "Symmetrical dianhydride containing ester group and long aliphatic chain" refers to a symmetrical structure containing one benzene ring, two straight-chain aliphatic hydrocarbon groups and two trimellitic anhydrides. Among them, two symmetrical positions of the benzene ring are respectively connected to a straight-chain aliphatic hydrocarbon group with the same structure, and the two trimellitic anhydrides with the same structure are respectively connected to two straight-chain aliphatic hydrocarbon groups after losing one H; the straight-chain aliphatic hydrocarbon group refers to an aliphatic hydrocarbon group with 2 to 8 carbon atoms in the main chain.
[0042] The polyimide precursor solution prepared by traditional technology generally has a high molecular weight and high viscosity, which makes it difficult to process and obtain a uniform film. Reducing the viscosity by reducing the solid content will lead to a decrease in the film thickness of the polyimide precursor solution, which is not conducive to high solid content and low viscosity applications. In addition, the traditional process for preparing polyimide precursor solution has a long synthesis time, generally more than 20 hours, which seriously affects the production efficiency and economic benefits of the product.
[0043] In one aspect of the present application, an embodiment provides a polyimide precursor solution, wherein the raw materials for preparing the polyimide precursor solution include a diamine monomer and a dianhydride monomer; the diamine monomer includes an aromatic diamine, and the dianhydride monomer includes a symmetrical dianhydride containing an ester group and a long fatty chain;
[0044] The symmetrical dianhydride containing an ester group and a long fatty chain is:
[0045] ,
[0046] Among them, n=m, 2≤m≤8, 2≤n≤8.
[0047] The monomers for preparing the above-mentioned polyimide precursor solution include diamine monomers and dianhydride monomers. The dianhydride monomer adopts the symmetrical dianhydride shown in formula (1), which contains an ester group and a long fatty chain. The obtained polyimide precursor solution has the characteristics of high solid content and low viscosity. The present application introduces the symmetrical dianhydride containing an ester group and a long fatty chain shown in formula (1) into the monomers for preparing the polyimide precursor solution, which reduces the reactivity of the monomer, hinders the polymerization between molecules, and effectively reduces the viscosity of the polymerization reaction system, so that the polyimide precursor solution has a high solid content and low viscosity. In addition, the polyimide precursor solution of the present application can be normally cast into a film, which improves the leveling and operability of the polyamic acid slurry. The subsequent formed film material has excellent performance, not only the film layer thickness is uniform, but also the smoothness and transparency are good.
[0048] The present application introduces a symmetrical dianhydride containing an ester group and a long fatty chain as shown in formula (1). During the dissolution process in the solvent, due to the certain polarity of the carbon-oxygen double bond and the carbon-oxygen single bond, dipole-dipole interactions or hydrogen bonds can be formed with the solvent molecules, thereby promoting the dissolution process, accelerating the dissolution rate, and improving the synthesis efficiency of polyamic acid.
[0049] In some embodiments, the polyimide precursor solution further comprises silica sol, and the silica sol is doped with the diamine monomer and the dianhydride monomer to form polyamic acid. After doping with silica sol, not only the viscosity of the polyimide precursor solution is reduced, the film thickness can be guaranteed, and the obtained film material has excellent performance, the film surface is flat and smooth, there are no impurity defects such as bubbles and particles, the edges are very neat, and the obtained film material has high transparency.
[0050] Furthermore, the silica sol is nano-silicon dioxide particles uniformly dispersed in an organic solvent, with a solid content of ≤25% and a viscosity of ≤20 cP.
[0051] In some embodiments, the mass content of the silica sol in the polyimide precursor solution is 1% to 6%.
[0052] As an example, the mass content of the silica sol in the polyimide precursor solution may be 1%, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5%, and 6%, or may be within a range consisting of any two of the above point values as end values.
[0053] Furthermore, the amount of the silica sol added to the mass ratio of the polyimide precursor solution is 1% to 5%. The viscosity of the polyimide precursor solution obtained at this addition ratio is lower, as low as within 30 cP, and the obtained film performance is better.
[0054] Furthermore, the added amount of the silica sol accounts for 1.5% to 3.5% of the mass of the polyimide precursor solution. At this addition ratio, the viscosity of the polyimide precursor solution is further reduced, and the obtained film has better performance.
[0055] In some of the embodiments, the symmetrical dianhydride is selected from at least one of trimellitic anhydride-1,4-benzenediethanol ester, trimellitic anhydride-1,4-benzenedipropanol ester, trimellitic anhydride-1,4-benzenedibutyl ester, trimellitic anhydride-1,4-benzenedipentanol ester, trimellitic anhydride-1,4-benzenedixanol ester, trimellitic anhydride-1,4-benzenedihexanol ester, and trimellitic anhydride-1,4-benzenedioctyl ester.
[0056] In some embodiments, the aromatic diamine is a rigid aromatic diamine. Rigid aromatic diamine is an aromatic diamine having both a rigid structure and two amino groups. Due to its rigid structure, the rigid aromatic diamine can provide the polymer with good dimensional stability and thermal stability in the polymerization reaction; in the synthesis of polyamic acid, the rigid aromatic diamine is used as a monomer to react with a symmetrical dianhydride containing an ester group and a long fatty chain. Its rigid structure ultimately makes the obtained polyimide molecular chain have higher rigidity, so that the polyimide material has advantages such as higher glass transition temperature, good mechanical properties and thermal stability.
[0057] In some embodiments, the aromatic diamine is selected from: 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl, 4,4'-diaminodiphenyl sulfone, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-[1,4-phenylbis(oxy)]bis(3-methylaniline), 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline], 2,2-bis[4-(4-aminophenoxy)benzene]hexafluoropropane, 4,4'-bis(4-aminophenoxy)benzophenone, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, and at least one of 2,5-bis(4-aminophenoxy)biphenyl.
[0058] The structural formula of 4,4'-diaminodiphenyl ether is:
[0059]
[0060] The structural formula of 3,4-diaminodiphenyl ether is:
[0061]
[0062] The structural formula of 4,4'-diamino-2,2'-dimethylbiphenyl is:
[0063]
[0064] The structural formula of 4,4''-diaminoterphenyl is:
[0065]
[0066] The structural formula of 4,4'-diaminodiphenyl sulfone is:
[0067]
[0068] 4,4'-Diamino-3,3'-dimethylbiphenyl
[0069]
[0070] The structural formula of 4,4'-[1,4-phenylbis(oxy)]bis(3-methylaniline) is:
[0071]
[0072] The structural formula of 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline] is:
[0073]
[0074] The structural formula of 2,2-bis[4-(4-aminophenoxy)benzene]hexafluoropropane is:
[0075]
[0076] The structural formula of 4,4'-bis(4-aminophenoxy)benzophenone is:
[0077]
[0078] The structural formula of 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene is:
[0079]
[0080] The structural formula of 2,5-bis(4-aminophenoxy)biphenyl is:
[0081]
[0082] The structural formula of 1,4-bis(4-aminophenoxy)benzene is:
[0083]
[0084] In some embodiments, the molar ratio of the symmetrical dianhydride to the aromatic diamine is 1:0.97-1.2. At this molar ratio, the symmetrical dianhydride containing an ester group and a long aliphatic chain and the aromatic diamine synergistically enhance the effect, thereby obtaining a polyimide precursor solution with a lower viscosity.
[0085] In some embodiments, the raw materials for preparing the polyimide precursor solution include diamino-3,3'-dimethylbiphenyl and trimellitic anhydride-1,4-phenylenedipropanol ester.
[0086] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diamino-3,3'-dimethylbiphenyl and trimellitic anhydride-1,4-butylbenzene.
[0087] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diamino-3,3'-dimethylbiphenyl and trimellitic anhydride-1,4-phenylenediol ester.
[0088] In some embodiments, the raw materials for preparing the polyimide precursor solution include diamino-3,3'-dimethylbiphenyl, trimellitic anhydride-1,4-phenylenedipropanol ester and silica sol.
[0089] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diamino-3,3'-dimethylbiphenyl, trimellitic anhydride-1,4-butylbenzene and silica sol.
[0090] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diamino-3,3'-dimethylbiphenyl, trimellitic anhydride-1,4-phenylenediol ester and silica sol.
[0091] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diaminodiphenyl ether, trimellitic anhydride-1,4-phenylenedipropanol ester and silica sol.
[0092] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diaminodiphenyl ether, trimellitic anhydride-1,4-butylbenzene and silica sol.
[0093] In some embodiments, the raw materials for preparing the polyimide precursor solution include 4,4'-diaminodiphenyl ether, trimellitic anhydride-1,4-phenylenediol ester and silica sol.
[0094] The second aspect of the present application provides a method for preparing the polyimide precursor solution as described in the first aspect, comprising the following steps:
[0095] The aromatic diamine and the symmetrical dianhydride are subjected to polymerization reaction in a solvent to obtain the precursor solution.
[0096] The monomers for preparing the above-mentioned polyimide precursor solution include diamine monomers and dianhydride monomers. The dianhydride monomer adopts a symmetrical dianhydride containing an ester group and a long fatty chain. The symmetrical dianhydride containing an ester group and a long fatty chain and an aromatic diamine are polymerized together to prepare the polyimide precursor solution, which reduces the reactivity of the monomer, hinders the polymerization between molecules, and effectively adjusts the viscosity of the polymerization reaction system, so that the polyimide precursor solution has a low viscosity while having a high solid content. The present application introduces a symmetrical dianhydride containing an ester group and a long fatty chain. During its dissolution in a solvent, due to the certain polarity of the carbon-oxygen double bond and the carbon-oxygen single bond, it can form dipole-dipole interactions or hydrogen bonds with organic solvent molecules, thereby promoting dissolution, accelerating the dissolution rate, and improving the synthesis efficiency. In addition, symmetrical dianhydrides and aromatic diamines containing ester groups and long fatty chains are used to prepare polyimide precursor solutions. The prepared polyimide precursor solutions can be normally cast into films, which improves the leveling and operability of the polyimide precursor solutions, and the subsequent formed film materials have excellent performance.
[0097] In some embodiments, after the polymerization reaction and before obtaining the precursor solution, the following step is further included: adding silica sol to the reaction solution obtained from the polymerization reaction and blending them to obtain a precursor solution doped with silica sol.
[0098] In some embodiments, before the polymerization reaction, the aromatic diamine is first dissolved in the solvent, and the symmetrical dianhydride is added after the aromatic diamine is dissolved. When the aromatic diamine is dissolved in the solvent, the solvent is heated to a temperature of 50° C. to 100° C. Increasing the solvent temperature to 50° C. to 100° C. can accelerate the dissolution of the diamine monomer and shorten the monomer dissolution time. After the diamine monomer is completely dissolved, the dianhydride monomer is added for copolymerization without lowering the polymerization temperature, thereby improving production efficiency.
[0099] Furthermore, the solvent temperature is 65° C. to 100° C. Within this temperature range, the monomer dissolution time is further shortened, and the polyamic acid synthesis efficiency is improved.
[0100] In some embodiments, the solvent is selected from at least one of N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, and N,N-dimethylformamide.
[0101] The solvent is preferably N-methylpyrrolidone, N,N-dimethylacetamide, or a mixture of N-methylpyrrolidone and N,N-dimethylacetamide in any proportion.
[0102] In some embodiments, the polymerization reaction temperature is 65°C to 120°C. After the diamine monomer is completely dissolved, the dianhydride monomer is added for copolymerization, and a relatively high polymerization temperature is maintained. The viscosity of the polyimide precursor solution obtained within this temperature range is relatively low, and the surface of the film material obtained subsequently is not prone to whitening and has a relatively low haze.
[0103] As an example, the polymerization reaction temperature may be 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C, 110°C, 111°C, 112°C, 113°C, 114°C The temperature can be 9°C, 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C, 110°C, 111°C, 112°C, 113°C, 114°C, 115°C, 116°C, 117°C, 118°C, 119°C, and 120°C, and can also be within the range consisting of any two of the above point values as end values, preferably 65°C ~ 110°C, more preferably 70°C ~ 100°C.
[0104] Furthermore, the polymerization reaction temperature is 70° C. to 100° C. At a polymerization reaction temperature of 70° C. to 100° C., the viscosity of the polyimide precursor solution is further reduced, and the leveling and operability of the polyimide precursor solution are further improved, and the surface of the prepared film is not easy to whiten and has a low haze.
[0105] In some embodiments, the polymerization reaction time is 5 h to 12 h. The monomer polymerization time is reduced and the reaction time is controlled within 5 to 12 h to ensure that the obtained slurry is clear and transparent.
[0106] As an example, the polymerization reaction time can be 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h and 12 h, or it can be in the range of any two of the above point values as end values. The synthesis time of the traditional process for preparing polyamic acid is usually more than 20 hours. In the preparation method, the reaction time can be controlled within 5h~12h, which improves the production efficiency. Within the reaction time of 5h~12h, the leveling and operability of the polyamic acid slurry are excellent.
[0107] The third aspect of the present application provides a polyimide precursor solution, which is prepared by the preparation method described in the second aspect.
[0108] A fourth aspect of the present application provides a polyimide film, characterized in that the polyimide film is prepared by coating the polyimide precursor solution described in the third aspect and then subjecting it to thermal imidization or chemical imidization; or
[0109] The monomers for preparing the polyimide film include diamine monomers and dianhydride monomers, wherein the diamine monomers include aromatic diamines, and the dianhydride monomers include symmetrical dianhydrides represented by formula (1);
[0110] (1),
[0111] Among them, n=m, 2≤m≤8, 2≤n≤8.
[0112] The fifth aspect of the present application provides a resin product comprising the polyimide film as described in the fourth aspect.
[0113] The following are specific embodiments.
[0114] Example 1
[0115] Under the protection of nitrogen atmosphere, 20 grams of N-methylpyrrolidone was added to a clean and dry reactor, and 1.3962 grams of 4,4'-diamino-3,3'-dimethylbiphenyl was added after heating to 90°C. After stirring until completely dissolved, 3.6038 grams of trimellitic anhydride-1,4-dipropanol ester was added, and the reaction temperature was maintained at 90°C and stirred for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid solution. 3wt% of silica sol was mixed into the cooled polyamic acid solution, and stirred until it was uniform to obtain a polyimide precursor solution.
[0116] The polyimide precursor solution is baked at 230° C. to obtain a polyimide film material, the surface of the film material is smooth and transparent.
[0117] Example 2
[0118] Under the protection of nitrogen atmosphere, 20 grams of N-methylpyrrolidone was added to a clean and dry reactor, and 1.3460 grams of 4,4'-diamino-3,3'-dimethylbiphenyl was added after heating to 90°C. After stirring until completely dissolved, 3.6540 grams of trimellitic anhydride-1,4-butylbenzene was added. The reaction temperature was maintained at 90°C and the stirring reaction was continued for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid solution. 3 wt% of silica sol was mixed into the cooled polyamic acid solution, and the polyimide precursor solution was obtained after stirring until it was uniform.
[0119] The polyimide precursor solution is baked at 230° C. to obtain a polyimide film material, the surface of the film material is smooth and transparent.
[0120] Example 3
[0121] Under the protection of nitrogen atmosphere, 20 grams of N-methylpyrrolidone was added to a clean and dry reactor, heated to 90°C, 1.2993 grams of 4,4'-diamino-3,3'-dimethylbiphenyl was added, and 3.7007 grams of trimellitic anhydride-1,4-benzenediol ester was added after stirring until completely dissolved. The reaction temperature was maintained at 90°C and stirred for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid solution. 3wt% of silica sol was mixed into the cooled polyamic acid solution and stirred until it was uniform to obtain a polyimide precursor solution.
[0122] The polyimide precursor solution is baked at 230° C. to obtain a polyimide film material, the surface of the film material is smooth and transparent.
[0123] Example 4
[0124] Example 4 is basically the same as Example 1, except that the amount of silica sol added is 7 wt %.
[0125] The obtained film material has a slight whitening, increased haze, and fine lines appear on the surface.
[0126] Example 5
[0127] Example 5 is substantially the same as Example 1, except that no silica sol is added.
[0128] Example 6
[0129] Example 6 is substantially the same as Example 1, except that an equal molar amount of 4,4'-diaminodiphenyl ether is used to replace 4,4'-diamino-3,3'-dimethylbiphenyl.
[0130] Example 7
[0131] Example 7 is substantially the same as Example 1, except that the reaction temperature is 130°C.
[0132] The polyimide precursor solution is baked at 230° C. to obtain a polyimide film material, the surface of which is white and has a high haze.
[0133] Comparative Example 1
[0134] Under the protection of nitrogen atmosphere, 20 grams of N-methylpyrrolidone was added to a clean and dry reactor, heated to 90°C, 2.0834 grams of 4,4'-diamino-3,3'-dimethylbiphenyl was added, stirred until completely dissolved, and then 2.9166 grams of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added. The reaction temperature was kept at 90°C and stirred for 10 hours to obtain a light yellow homogeneous and transparent polyamic acid solution. 3wt% of silica sol was mixed into the cooled polyamic acid solution and stirred until it was uniform to obtain a polyimide precursor solution. The polyimide precursor solution was baked at 230°C to obtain a polyimide film material.
[0135] The viscosity and solid content of the polyimide precursor solutions prepared in Examples 1 to 7 and Comparative Example 1 were tested. The test results are shown in Table 1 below.
[0136] Table 1
[0137]
[0138] As can be seen from Table 1 above, the viscosity of the polyimide precursor solution prepared by using the symmetrical dianhydride containing an ester group and a long fatty chain as the dianhydride monomer in Examples 1 to 7 is significantly lower than the viscosity of the polyimide precursor solution prepared by using 3,3',4,4'-biphenyltetracarboxylic dianhydride as the dianhydride monomer in Comparative Example 1. It can be seen from Examples 4 and 5 that the addition of silica sol can reduce the viscosity of the polyimide precursor solution, and the effect is better when the addition amount of silica sol accounts for the mass ratio of the polyimide precursor solution in the range of 1% to 5%. It can be seen from Example 7 that the polymerization reaction temperature is better when it is in the range of 70°C to 90°C.
[0139] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0140] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A polyimide precursor solution, characterized in that: The polyimide precursor solution comprises a polyimide precursor, and the raw materials for preparing the polyimide precursor comprise a diamine monomer and a dianhydride monomer; the diamine monomer comprises an aromatic diamine, and the dianhydride monomer comprises a symmetrical dianhydride represented by formula (1); （1）， Among them, n=m, 2≤m≤8, 2≤n≤8.
2. The polyimide precursor solution according to claim 1, characterized in that The polyimide precursor solution further includes silica sol, and the silica sol dopes the diamine monomer and the dianhydride monomer to form polyamic acid.
3. The polyimide precursor solution according to claim 1, characterized in that: The mass content of the silica sol in the polyimide precursor solution is 1% to 5%.
4. The polyimide precursor solution according to claim 1, characterized in that: The symmetrical dianhydride is selected from at least one of trimellitic anhydride-1,4-benzenediethanol ester, trimellitic anhydride-1,4-benzenedipropanol ester, trimellitic anhydride-1,4-benzenedibutyl ester, trimellitic anhydride-1,4-benzenedipentanol ester, trimellitic anhydride-1,4-benzenedixanol ester, trimellitic anhydride-1,4-benzenedihexanol ester, and trimellitic anhydride-1,4-benzenedioctyl ester.
5. The polyimide precursor solution according to any one of claims 1 to 4, characterized in that: The aromatic diamine is a rigid aromatic diamine.
6. The polyimide precursor solution according to any one of claims 1 to 4, characterized in that: The aromatic diamine is selected from the group consisting of: 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4''-diaminoterphenyl, 4,4'-diaminodiphenyl sulfone, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-[1,4-phenylbis(oxy)]bis(3-methylaniline), 4,4'-[1,4-phenylbis(oxy)]bis[3-(trifluoromethyl)aniline], 2,2-bis[4-(4-aminophenoxy)benzene]hexafluoropropane, 4,4'-bis(4-aminophenoxy)benzophenone, 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene, and 2,5-bis(4-aminophenoxy)biphenyl.
7. The polyimide precursor solution according to any one of claims 1 to 4, characterized in that: The molar ratio of the symmetrical dianhydride to the aromatic diamine is 1:0.97-1.
2.
8. A method for preparing a polyimide precursor solution according to any one of claims 1 to 7, characterized in that: The following steps are involved: The aromatic diamine and the symmetrical dianhydride are subjected to polymerization reaction in a solvent to obtain the precursor solution.
9. The method for preparing a polyimide precursor solution according to claim 8, wherein: After the polymerization reaction is carried out and before the precursor solution is obtained, the following step is further included: adding silica sol to the reaction solution obtained from the polymerization reaction for blending to obtain a precursor solution doped with silica sol.
10. The method for preparing a polyimide precursor solution according to claim 8, wherein: Before the polymerization reaction, the aromatic diamine is first dissolved in the solvent, and the symmetrical dianhydride is added after the aromatic diamine is dissolved. The aromatic diamine dissolution satisfies at least one of the following conditions: (1) heating the solvent to a temperature of 50°C to 100°C; (2) The solvent is at least one selected from N-methylpyrrolidone, m-cresol, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone and N,N-dimethylformamide.
11. The method for preparing a polyimide precursor solution according to any one of claims 8 to 10, characterized in that: The polymerization reaction satisfies at least one of the following conditions: (1) The polymerization reaction temperature is 65°C to 110°C; (2) The polymerization reaction time is 5h~12h.
12. A polyimide precursor solution, characterized in that: The polyimide precursor solution is prepared by the preparation method according to any one of claims 8 to 11.
13. A polyimide film, characterized in that: The polyimide film is prepared by coating the polyimide precursor solution according to claim 12 and then subjecting it to thermal imidization or chemical imidization; or The monomers for preparing the polyimide film include diamine monomers and dianhydride monomers, wherein the diamine monomers include aromatic diamines, and the dianhydride monomers include symmetrical dianhydrides represented by formula (1); （1）， Among them, n=m, 2≤m≤8, 2≤n≤8.
14. A resin product, characterized in that: Comprising the polyimide film as claimed in claim 13.