A method for preparing a high-temperature-resistant photosensitive polyimide resin and transparent film, and selectively metallizing the surface thereof and applications

Abstract

The application relates to the technical field of high polymer materials, in particular to a kind of preparation of high-temperature-resistant photosensitive polyimide resin and transparent film and a surface selective metallization method and application thereof, wherein the polyimide resin macromolecular main chain contains imidazole derivative structure, and the side chain contains polyphenol hydroxyl structure; the polyimide film prepared by using the resin has good mechanical properties, solubility, optical transmittance, thermal stability and photosensitivity, and has the characteristics of surface selective metallization; the film can also reduce the precursor metal ions of electroless plating catalyst under ultraviolet light or sunlight irradiation, realize the surface selective metallization of polyimide, and the metal coating surface has low roughness, low resistivity, and strong adhesion between the photosensitive polyimide; therefore, it has wide application prospect in the fields of flexible electronic device substrate material, composite current collector base material in new energy soft package battery, supercapacitor and flexible display material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, and particularly relates to a preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film, and a surface selective metallization method and application thereof. BACKGROUND

[0002] The polyimide resin is an insulating material with good heat resistance, high mechanical strength and excellent comprehensive performance, and the film thereof is widely applied to the fields of flexible electronics, electrical engineering, aerospace, etc. The polyimide surface metallization is one of important ways for functional modification of the polyimide film. However, the traditional process generally adopts a hot pressing method to composite the polyimide film and a copper foil, and then etches a specific metal line through a "subtractive manufacturing" method for manufacturing a flexible circuit board, or deposits a large-area continuous metal on the surface of the polyimide film through a magnetron sputtering / high-temperature evaporation method, and further uses the same for manufacturing a composite copper foil of the flexible circuit board or a composite current collector of a new energy battery.

[0003] However, the polyimide film copper-clad circuit board manufactured through the above traditional process technology generally has the problems of relatively poor adhesion of the metal plating layer, relatively rough surface of the metal plating layer, complex manufacturing process, relatively high resistivity and high production cost, which greatly limits the further application of the polyimide film in the fields of flexible electronic materials and new energy battery materials.

[0004] Therefore, it is particularly important to develop an intrinsic photosensitive polyimide with surface metallization capability. For example, the patent technical document CN110804181B discloses a transparent photosensitive polyimide resin, a polyimide film and a preparation method thereof. The polyimide resin and the film prepared by the application have photosensitivity, can discolor under ultraviolet irradiation, have the characteristics of directly visualizing the observation of the photo-induced modification region, are colorless and transparent, have good flexibility, can be used for manufacturing circuit boards of flexible electronic devices, can be subjected to surface pattern metallization, and the metal in the plating layer and the resin can be recycled through dissolving the film matrix in the subsequent process. However, due to the introduction of the spiropyran photoresponsive group, the heat resistance of the photosensitive polyimide is limited to a certain extent.

[0005] Therefore, according to the related technologies in the above, it is urgent to develop a preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film, and a surface selective metallization method and application thereof. SUMMARY

[0006] In view of the above, the purpose of the present application is to provide a preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film, and a surface selective metallization method and application thereof, so as to solve the problems of the relatively rough surface of the metal plating layer of the polyimide film copper-clad circuit board, the complex metallization process, the relatively high resistivity and the relatively poor adhesion between the photosensitive polyimide and the metal plating layer in the prior art.

[0007] Based on the above purpose, the application provides a preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film, a surface selective metallization method thereof and application.

[0008] A preparation method of a high-temperature-resistant photosensitive polyimide resin, the molecular main chain of the high-temperature-resistant photosensitive polyimide resin containing an imidazole derivative structure, and the molecular side chain containing a polyphenol hydroxyl structure, that is, any one of the structures shown in formula (I), formula (II), formula (III), formula (IV):

[0009]

[0010]

[0011] Ar0 in the structure of formula (I), formula (II), formula (III), formula (IV) is the residue of a binary primary amine imidazole derivative structure;

[0012] Ar1 in the structure of formula (I), formula (II), formula (III), formula (IV) is a dianhydride monomer residue;

[0013] Ar2 and R6 in the structure of formula (I), formula (II), formula (III), formula (IV) are substituents on N in the Ar0 imidazole ring;

[0014] Ar2 in the structure of formula (I), formula (III) is an aromatic ketone derivative structure;

[0015] R1, R2, R3, R4 and R5 in the structure of formula (I), formula (II), formula (III), formula (IV) are any one of H and OH;

[0016] R6 in the structure of formula (II), formula (IV) is an aliphatic ketone derivative structure;

[0017] R' in the structure of formula (III), formula (IV) is a binary primary amine monomer residue.

[0018] Preferably, Ar0 is the residue of any one or several of the following imidazole derivative binary primary amine monomers:

[0019]

[0020] X in the structure of formula (I) is any one of -H, -CH3, -CF3, F, Cl, Br and I; Ar1 is the residue of any one or several of the following dianhydride monomers:

[0021]

[0022] ​

[0023] said R' is the residue of any one or several binary primary amine monomers as shown in the following structures:

[0024]

[0025] Preferably, the preparation method of the high-temperature-resistant photosensitive polyimide resin is as follows:

[0026] Step A1. Under a dry nitrogen atmosphere, the diamine monomer and dianhydride monomer are dissolved in an organic solvent and reacted at 0-25℃ for 6-25h, then a catalyst and a dehydrating agent are added, refluxed at 80-100℃ for 1-3h, then cooled to room temperature after refluxing at 110-120℃ for 3-6h, then poured into precipitant 1, and then filtered, washed and dried to obtain the photosensitive polyimide resin;

[0027] Step A2. Under a dry nitrogen atmosphere, the photosensitive polyimide resin is dissolved in an organic solvent, sodium hydride is added at 0-25℃, stirred for 1-3h, then a small molecule halide is added, reacted for 3-6h, then poured into precipitant 2, and then filtered, washed and dried to obtain the high-temperature-resistant photosensitive polyimide resin.

[0028] Preferably, the molar ratio of the diamine monomer, dianhydride monomer, catalyst and dehydrating agent in step A1 is 0.05:0.051-0.06:0.11-5:0.06-10; the mass ratio of the photosensitive polyimide resin, organic solvent, small molecule halide and precipitant 2 in step A2 is 5:100-110:2.15-9.5:450-500.

[0029] Preferably, the organic solvent is any one of acetone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, phenol, benzonitrile, m-cresol, p-chlorophenol, p-chlorometa-cresol, nitrobenzene;

[0030] The catalyst is any one or more of pyridine, benzoic acid, p-hydroxybenzoic acid, quinoline, isoquinoline, triethylamine or N,N-dimethylaniline;

[0031] The dehydrating agent is any one or more of acetic anhydride, propionic anhydride, butyric anhydride, phthalic anhydride;

[0032] The precipitant 1 is any one and a mixed solution of multiple of methanol, ethanol, water;

[0033] The small molecule halide is any one of halogenated aromatic or aliphatic polyphenol hydroxyl small molecules;

[0034] The precipitant 2 is a mixed solution of any one or more of dilute hydrochloric acid and methanol, ethanol, water;

[0035] The pH of the precipitant 2 is 1.0-3.5.

[0036] A preparation method of a transparent film, comprising the following steps:

[0037] Dissolve the high-temperature-resistant photosensitive polyimide resin in a solvent, spin-coat or blade-coat the solution on a clean glass plate after standing and defoaming, and dry at 95-180℃ to form a film, thereby obtaining a transparent film.

[0038] Preferably, the mass ratio of the high-temperature-resistant photosensitive polyimide resin and the solvent is 5-15:50-120; the solvent is any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, butyrolactone, acetone, tetrahydrofuran, and m-cresol; and the thickness of the polyimide wet film is 20-800μm.

[0039] A surface-selective metallization method of a transparent film, comprising the following steps:

[0040] Method 1. Use an aqueous silver nitrate solution as ink, print a designed pattern on the surface of the transparent photosensitive polyimide film by means of an inkjet printer, then irradiate the pretreated film A with ultraviolet light or sunlight, clean the surface with pure water, immerse in a plating solution at 20-80℃ for 5-120min, and finally clean with pure water, dry, thereby obtaining a polyimide flexible circuit board A with a metal pattern plated on the surface;

[0041] The polyimide flexible circuit board A with a metal pattern plated on the surface in Method 1 has a 2-layer structure, wherein the upper layer is a metal pattern layer and the lower layer is a photosensitive polyimide film layer; and the area of the metal pattern layer is smaller than that of the photosensitive polyimide film layer.

[0042] Method 2. Use a silk screen printing plate with a specially designed openwork pattern and a solder resist ink to print a solder resist layer on the surface of the high-temperature-resistant transparent film and expose the reserved circuit pattern area, then immerse in an aqueous silver nitrate solution, subsequently irradiate the pretreated film B with ultraviolet light or sunlight, clean the surface with pure water, immerse in a plating solution at 20-80℃ for 5-120min, and finally clean with pure water, dry, thereby obtaining a polyimide flexible circuit board B with a metal pattern plated on the surface;

[0043] The polyimide flexible circuit board B with a metal pattern plated on the surface in Method 2 has a 2-layer structure, wherein the upper layer is a metal pattern and solder resist ink pattern co-planar layer and the lower layer is a photosensitive polyimide film layer; and the area of the metal pattern layer is smaller than that of the photosensitive polyimide film layer.

[0044] Method 3. After the transparent film surface is cleaned, the whole is immersed in silver nitrate aqueous solution, one side or both sides of the film is irradiated by ultraviolet light or sunlight, and then the surface is cleaned with pure water. After that, it is immersed in a plating solution at 20-80℃ for 5-120min, and then cleaned with pure water and dried to obtain a polyimide flexible copper-clad plate C with a continuous metal layer plated on the surface;

[0045] The polyimide flexible copper-clad plate C with a continuous metal layer plated on the surface in Method 3 is any one of a polyimide metal composite film plated with a metal layer on one side or a polyimide metal composite film plated with a metal layer on both sides.

[0046] The polyimide metal composite film plated with a metal layer on one side is a 2-layer structure, the upper layer is a continuous metal layer, and the lower layer is a photosensitive polyimide layer; wherein the area of the continuous metal layer is equal to the area of the photosensitive polyimide film.

[0047] The polyimide metal composite film plated with a metal layer on both sides is a 3-layer structure, the upper and lower layers are continuous metal layers, and the middle layer is a photosensitive polyimide layer; wherein the area of the continuous metal layer is equal to the area of the photosensitive polyimide film.

[0048] Method 4. The photosensitive polyimide resin is dissolved with an organic solvent to obtain a photosensitive polyimide solution. The photosensitive polyimide solution is patterned and printed on the surface of any polymer film by using a dispensing printer, and then dried at 80℃ to obtain a composite photosensitive film with a photosensitive polyimide pattern on the surface. The whole is immersed in silver nitrate aqueous solution, and then the surface is cleaned with pure water after the film is irradiated by ultraviolet light or sunlight. After that, it is immersed in a plating solution at 20-80℃ for 5-120min, and then cleaned with pure water and dried to obtain a composite flexible circuit board D with a metal layer plated on the surface of the photosensitive polyimide pattern.

[0049] The polymer film in Method 4 is any one of a polypropylene film, a polyethylene film, a polyethylene terephthalate film, a polystyrene film, and a liquid crystal polymer film.

[0050] The composite flexible circuit board D with a metal layer plated on the surface of the photosensitive polyimide pattern in Method 4 is a 3-layer structure, the top layer is a metal pattern layer, the middle layer is a photosensitive polyimide pattern layer, and the bottom layer is a polymer film support layer; wherein the area of the metal pattern layer is equal to the area of the photosensitive polyimide pattern layer, and smaller than the area of the polymer film support layer.

[0051] Preferably, the concentration of the silver nitrate aqueous solution is 0.005-2.0mol / L; the wavelength range of the ultraviolet light during irradiation is 200-450nm, the sunlight is full-spectrum sunlight, and the irradiation time is 1.5-60min; the plating solution is any one of a copper plating solution, a nickel plating solution, a silver plating solution, and a gold plating solution.

[0052] The application relates to a preparation method of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a surface selective metallization method and application thereof, and the preparation method of the high-temperature-resistant photosensitive polyimide resin, the preparation method of the transparent film and the surface selective metallization method of the transparent film can be applied to the fields of flexible electronic device substrates, flexible displays, flexible solar cells and new energy battery composite current collectors; the transparent film can be used for preparing a copper-coated polyimide film, supercapacitor electrode sheets, solar cell electrode sheets and new energy battery composite current collectors.

[0053] The application has the following beneficial effects:

[0054] The application provides a preparation method of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a surface selective metallization method and application thereof. The application prepares a high-temperature-resistant photosensitive polyimide resin. The polyimide resin contains an imidazole derivative structure on a molecular main chain and is grafted with a polyphenol hydroxyl structure molecule on a molecular chain side chain. The polyimide resin can complex silver ions and reduce the silver ions into silver atoms under the irradiation of ultraviolet light or sunlight, so as to catalyze the chemical deposition of metal. The metallization process does not damage the surface of the film and does not need an adhesive layer. Therefore, the transparent film prepared by using the polyimide resin has good photosensitivity, thermal stability and mechanical properties. The adhesion between a metal plating layer on the film and a polyimide film surface is stronger. The surface of the plating layer is smoother. The thickness of the plating layer is more uniform. The transparent film can be selectively metal patterned or large-area metallized. The preparation and metallization process of the photosensitive polyimide resin and the film are simple, high in production efficiency, low in cost, small in pollution, great in economic benefits and environmental protection significance. Therefore, compared with the prior art, the transparent film prepared by using the application has a wider application prospect in the fields of flexible electronic device substrates, new energy soft-pack battery composite current collector substrates, solar cell electrode sheet substrates and flexible display materials. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only a part of the application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0056] Figure 1 The physical appearance of the polyimide flexible circuit board prepared in the embodiment of the application and plated with a metal pattern is shown in the figure. Figure 1 A is the physical appearance of the polyimide flexible circuit board prepared in the embodiment 1 of the application and plated with a metal pattern. Figure 1 B is the physical appearance of the polyimide flexible circuit board prepared in the embodiment 3 of the application and plated with a metal pattern.

[0057] Figure 2 The Fourier transform infrared spectrogram of the transparent film prepared in Example 1 of the present application;

[0058] Figure 3 The thermogravimetric analysis curve of the transparent film prepared in Example 1 of the present application;

[0059] Figure 4 The photos of the transparent film surface metal plating layer prepared in Example 4 of the present application before and after the grid test, wherein Figure 4 A is the optical photo of the sample after being scored with a grid; Figure 4 B is the optical photo of the sample surface after being peeled off using 3M tape; Figure 4 C is the optical photo of the metal plating layer being peeled off on the 3M tape;

[0060] Figure 5 The evaluation standard photo of the metal plating layer adhesion test of the present application. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application is further described in detail below in combination with specific examples.

[0062] Example 1: Preparation of a high-temperature-resistant photosensitive polyimide resin and transparent film and a method for selectively metallizing the surface thereof:

[0063] S1. Under a dry nitrogen atmosphere, 0.0500 mol of 2-(4-aminophenyl)-5-aminobenzimidazole and 0.0510 mol of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride were dissolved in 150 mL of N,N-dimethylformamide and stirred at 0°C for 24 h, after which 0.1100 mol of pyridine and 0.0600 mol of acetic anhydride were added, refluxed at 80°C for 1 h, and then refluxed at 110°C for 5 h, and then poured into 450 mL of methanol, and then filtered, washed and dried to obtain a photosensitive polyimide resin; the weight average molecular weight of the photosensitive polyimide resin was 2.5 x 10 5 g / mol, and the number average molecular weight was 1.7 x 10 5 g / mol;

[0064] The result formula of the product obtained in the above step is as shown in the following formula:

[0065]

[0066] S2: 5 g of photosensitive polyimide resin was dissolved in 100 mL of dimethyl sulfoxide under a dry nitrogen atmosphere, 1.6 g of sodium hydride was added at 0°C, and after stirring for 2 h, 2.17 g of 4'-chloro-3,4-dihydroxybenzophenone was added, and the reaction was carried out for 3 h. Then, the reaction solution was poured into a mixed solution of 450 mL of dilute hydrochloric acid with a pH of 2 and methanol, and after filtration, washing, and drying, a high-temperature-resistant photosensitive polyimide resin was obtained. The structural formula of the product obtained in the above step is shown below:

[0067]

[0068] S3. 5 g of high-temperature-resistant photosensitive polyimide resin was dissolved in 105 g of N,N-dimethylformamide, and after standing to remove bubbles, the solution was spin-coated on a clean glass plate, and dried at 95°C to form a film, obtaining a transparent film with a thickness of 20 μm;

[0069] S4. A designed pattern was printed on the surface of the photosensitive polyimide film in an inkjet printer using a 0.005 mol / L silver nitrate aqueous solution, obtaining a pretreated film A;

[0070] S5. 24 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate, and 8 mg of 2,2'-bipyridine were dissolved in 450 mL of deionized water, obtaining a mixed solution;

[0071] S6. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide were dissolved in 475 mL of deionized water, and then 450 mL of the mixed solution was added, and stirred to obtain a chemical plating solution;

[0072] S7. The pretreated film A was irradiated with ultraviolet light with a wavelength range of 200 nm for 3 min, then washed with pure water, and then immersed in the chemical plating solution at 20°C for 5 min, and then washed with pure water, dried, obtaining a polyimide flexible circuit board A with a metal pattern plated on the surface;

[0073] The polyimide flexible circuit board A with a metal pattern plated on the surface is a 2-layer structure, the upper layer is a metal pattern layer, and the lower layer is a photosensitive polyimide film layer; wherein the area of the metal pattern layer is smaller than the area of the photosensitive polyimide film layer.

[0074] Example 2: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof:

[0075] S1. Under a dry protective atmosphere, 0.04 mol of 2-(4-aminophenyl)-5- aminobenzimidazole, 0.01 mol of 1,1-di(4-aminophenyl)cyclohexane and 0.055 mol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride were dissolved in 180 mL of phenol and stirred at 10°C for 24.5 h, after which 0.12 mol of triethylamine and 0.065 mol of butyric anhydride were added, refluxed at 90°C for 2 h, then at 115°C for 3 h, poured into 480 mL of ethanol, and after filtration, washing and drying, a photosensitive polyimide resin was obtained;

[0076] The structural formula of the product obtained in the above step is as shown in the following formula:

[0077]

[0078] S2. Under a dry protective atmosphere, 5 g of the photosensitive polyimide resin was dissolved in 105 mL of phenol, 1.65 g of sodium hydride was added at 10°C, stirred for 2.5 h, then 1.64 g of 3,4-dihydroxy-2'-chloroacetophenone was added, reacted for 5 h, poured into 480 mL of a mixed solution of dilute hydrochloric acid with a pH of 2.1 and ethanol, and after filtration, washing and drying, a high-temperature-resistant photosensitive polyimide resin was obtained;

[0079] The structural formula of the product obtained in the above step is as shown in the following formula:

[0080]

[0081] S3. 5 g of the high-temperature-resistant photosensitive polyimide resin was dissolved in 110 g of N,N-dimethylacetamide, after standing and defoaming, the solution was scraped and coated on a clean glass plate, and after drying at 130°C, a transparent film with a thickness of 400 μm was obtained;

[0082] S4. A designed pattern was printed on the surface of the photosensitive polyimide film in an inkjet printer using an aqueous silver nitrate solution with a concentration of 1.0 mol / L, and a pretreated film A was obtained;

[0083] S5. 24.5 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate and 8 mg of 2,2'-bipyridine were dissolved in 480 mL of deionized water to obtain a mixed solution;

[0084] S6. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of aqueous formaldehyde solution and 16 g of sodium hydroxide were dissolved in 490 mL of deionized water, then 480 mL of the mixed solution was added, and after stirring, a chemical plating solution was obtained;

[0085] S7. After the pretreated film A is irradiated with 365 nm ultraviolet light for 30 min, it is washed with pure water, then immersed in a 50℃ electroless plating solution for 60 min, and then washed with pure water and dried to obtain a polyimide flexible circuit board A with a metal pattern plated on the surface;

[0086] The polyimide flexible circuit board A with a metal pattern plated on the surface is a 2-layer structure, wherein the upper layer is a metal pattern layer and the lower layer is a photosensitive polyimide film layer; and the area of the metal pattern layer is smaller than that of the photosensitive polyimide film layer.

[0087] Example 3: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof

[0088] S1. Under a dry protective atmosphere, 0.04 mol of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.01 mol of 2,2'-bis(trifluoromethyl)diaminobiphenyl, and 0.06 mol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride were dissolved in 200 mL of m-cresol and stirred at 25℃ for 25 h, then 5 mol of quinoline and 10 mol of phthalic anhydride were added, refluxed at 100℃ for 3 h, and then refluxed at 120℃ for 6 h, and then poured into 500 mL of water, and then filtered, washed, and dried to obtain a photosensitive polyimide resin;

[0089] The structural formula of the product obtained in the above step is as shown in the following formula:

[0090]

[0091] S2. Under a dry protective atmosphere, 5 g of the photosensitive polyimide resin was dissolved in 110 mL of N-methylpyrrolidone, 1.7 g of sodium hydride was added at 25℃, stirred for 3 h, then 9.5 g of 4'-chloro-3,4-dihydroxybenzophenone was added, reacted for 6 h, and then poured into 500 mL of a mixed solution of dilute hydrochloric acid and water with a pH of 2.2, and then filtered, washed, and dried to obtain a high-temperature-resistant photosensitive polyimide resin;

[0092] The structural formula of the product obtained in the above step is as shown in the following formula:

[0093]

[0094] S3. 15 g of the high-temperature-resistant photosensitive polyimide resin was dissolved in 120 g of sulfolane, the solution was spin-coated on a clean glass plate after standing and defoaming, and then baked at 180℃ to obtain a transparent film with a thickness of 800 μm;

[0095] S4. Printing a solder resist layer on the surface of the high-temperature-resistant photosensitive polyimide film with a silk screen printing plate having a specific design of a screen pattern and a solder resist ink, and exposing a reserved circuit pattern area, and then soaking in a 2 mol / L silver nitrate aqueous solution to obtain a pretreated film B;

[0096] S5. Dissolving 25 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate, and 8 mg of 2,2'-bipyridine in 500 mL of deionized water to obtain a mixed solution;

[0097] S6. Dissolving 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide in 500 mL of deionized water, and then adding 500 mL of the mixed solution to obtain a chemical plating solution;

[0098] S7. Irradiating the pretreated film B with ultraviolet-near ultraviolet light with a wavelength range of 450 nm for 60 min, and then washing with pure water, and then immersing in the chemical plating solution at 80°C for 120 min, and then washing with pure water and drying to obtain a polyimide flexible circuit board B plated with a metal pattern on the surface;

[0099] The polyimide flexible circuit board B plated with a metal pattern on the surface is a 2-layer structure, the upper layer is a coplanar layer of the metal pattern and the solder resist ink pattern, and the lower layer is a photosensitive polyimide film layer; wherein the area of the metal pattern layer is smaller than the area of the photosensitive polyimide film layer.

[0100] Example 4: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof:

[0101] S1. In a dry protective atmosphere, 0.04 mol of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.01 mol of 2,2'-bis(trifluoromethyl)diaminobiphenyl, and 0.06 mol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride are dissolved in 200 mL of nitrobenzene and stirred at 25°C for 25 h, and then 5 mol of isoquinoline and 10 mol of propionic anhydride are added, and refluxed at 100°C for 3 h, and then refluxed at 120°C for 6 h, and then poured into 500 mL of water, and then filtered, washed, and dried to obtain a photosensitive polyimide resin;

[0102] The structural formula of the product obtained in the above step is as shown in the following formula:

[0103]

[0104] S2. Under a dry protective atmosphere, 5 g of photosensitive polyimide resin is dissolved in 110 mL of N-methylpyrrolidone, 1.7 g of sodium hydride is added at 25°C, after stirring for 3 h, 9.5 g of 4'-chloro-3,4-dihydroxybenzophenone is added, and the reaction is carried out for 6 h, then poured into a mixture of 500 mL of dilute hydrochloric acid and water with a pH of 2.2, and then filtered, washed and dried to obtain a high-temperature-resistant photosensitive polyimide resin;

[0105] The structural formula of the product obtained in the above step is as follows:

[0106]

[0107] S3. 15 g of high-temperature-resistant photosensitive polyimide resin is dissolved in 120 g of tetrahydrofuran, after standing and degassing, the solution is spin-coated on a clean glass plate, and then dried at 180°C to obtain a transparent film with a thickness of 800 μm;

[0108] S4. 25 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate and 8 mg of 2,2'-bipyridine are dissolved in 500 mL of deionized water to obtain a mixed solution;

[0109] S5. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide are dissolved in 500 mL of deionized water, then 500 mL of the mixed solution is added, and stirred uniformly to obtain a chemical plating solution;

[0110] S6. After cleaning the surface of the transparent film, it is completely immersed in a 2 mol / L silver nitrate aqueous solution, and the film is irradiated with sunlight on one side for 1.5 min, then the surface is washed with pure water, then immersed in a 20°C chemical plating solution for 5 min, and then washed with pure water and dried to obtain a polyimide flexible copper-clad plate C with a continuous metal layer plated on one side of the surface;

[0111] The polyimide metal composite film of the polyimide flexible copper-clad plate C with a continuous metal layer plated on one side of the surface is a 2-layer structure, the upper layer is a continuous metal layer, and the lower layer is a photosensitive polyimide layer; wherein the area of the continuous metal layer is equal to the area of the photosensitive polyimide film;

[0112] Example 5: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof:

[0113] S1. 0.04 mol of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.01 mol of 2,2'-bis(trifluoromethyl)diaminobiphenyl and 0.06 mol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride were dissolved in 200 mL of benzonitrile under a dry protective atmosphere and stirred at 25°C for 25 h, after which 5 mol of triethylamine and 10 mol of butyric anhydride were added, refluxed at 100°C for 3 h, and then refluxed at 120°C for 6 h, poured into 500 mL of water, and then filtered, washed and dried to obtain a photosensitive polyimide resin;

[0114] The structural formula of the product obtained in the above step is as shown in the following formula:

[0115]

[0116] S2. 5 g of the photosensitive polyimide resin was dissolved in 110 mL of acetone under a dry protective atmosphere, 1.7 g of sodium hydride was added at 25°C, stirred for 3 h, then 9.5 g of 4'-chloro-3,4-dihydroxybenzophenone was added, reacted for 6 h, poured into 500 mL of a mixed solution of dilute hydrochloric acid and water with a pH of 2.2, and then filtered, washed and dried to obtain a high-temperature-resistant photosensitive polyimide resin;

[0117] The structural formula of the product obtained in the above step is as shown in the following formula:

[0118]

[0119] S3. 15 g of the high-temperature-resistant photosensitive polyimide resin was dissolved in 120 g of N,N-dimethylformamide, the solution was spin-coated on a clean glass plate after standing and defoaming, and then baked at 180°C to obtain a transparent film with a thickness of 800 μm;

[0120] S4. 25 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate and 8 mg of 2,2'-bipyridine were dissolved in 500 mL of deionized water to obtain a mixed solution;

[0121] S5. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution and 16 g of sodium hydroxide were dissolved in 500 mL of deionized water, then 500 mL of the mixed solution was added, and stirred uniformly to obtain a chemical plating solution;

[0122] S6. After the surface of the transparent film was cleaned, it was immersed in a 2 mol / L silver nitrate aqueous solution, the film was irradiated with sunlight from both sides for 60 min, the surface was then washed with pure water, immersed in the chemical plating solution at 80°C for 120 min, and then washed with pure water and dried to obtain a polyimide flexible copper-clad plate C with a continuous metal layer plated on both sides of the surface.

[0123] The polyimide metal composite film of the polyimide flexible copper-clad plate C plated with continuous metal layers on both surfaces is a 3-layer structure, the upper and lower layers are continuous metal layers, and the middle layer is a photosensitive polyimide layer; wherein the area of the continuous metal layer is equal to the area of the photosensitive polyimide film;

[0124] Embodiment 6: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof:

[0125] S1. In a dry protective atmosphere, 0.04 mol of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.01 mol of 2,2'-bis(trifluoromethyl)diaminobiphenyl, and 0.06 mol of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride were dissolved in 200 mL of m-cresol and stirred at 25°C for 25 h, then 5 mol of isoquinoline and 10 mol of acetic anhydride were added, refluxed at 100°C for 3 h, and then refluxed at 120°C for 6 h, cooled to room temperature, poured into 500 mL of water, filtered, washed, and dried to obtain a photosensitive polyimide resin;

[0126] The structural formula of the product obtained in the above step is as follows:

[0127]

[0128] S2. In a dry protective atmosphere, 5 g of the photosensitive polyimide resin was dissolved in 110 mL of acetone, 1.7 g of sodium hydride was added at 25°C, stirred for 3 h, then 9.5 g of 4'-chloro-3,4-dihydroxybenzophenone was added, reacted for 6 h, poured into 500 mL of a mixed solution of dilute hydrochloric acid and water with a pH of 2.2, filtered, washed, and dried to obtain a high-temperature-resistant photosensitive polyimide resin;

[0129] The structural formula of the product obtained in the above step is as follows:

[0130]

[0131] S3. 25 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate, and 8 mg of 2,2'-bipyridine were dissolved in 500 mL of deionized water to obtain a mixed solution;

[0132] S4. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide were dissolved in 500 mL of deionized water, then 500 mL of the mixed solution was added, stirred uniformly to obtain a chemical plating solution;

[0133] S5. Dissolve the photosensitive polyimide resin with an organic solvent to obtain a photosensitive polyimide solution, pattern the photosensitive polyimide solution on the surface of the polymer film by using a dispensing printer, dry at 80°C to obtain a composite photosensitive film with a photosensitive polyimide pattern, immerse the whole in an aqueous silver nitrate solution, irradiate the film with ultraviolet light or sunlight, then wash the surface with pure water, then immerse in an electroless plating solution at 80°C for 120 min, then wash with pure water, dry, to obtain a composite flexible circuit board D with a metal layer plated on the surface of the photosensitive polyimide pattern;

[0134] The polymer film is any one of a polypropylene film, a polyethylene film, a polyethylene terephthalate film, a polystyrene film, and a liquid crystal polymer film.

[0135] The composite flexible circuit board D with a metal layer plated on the surface of the photosensitive polyimide pattern is a 3-layer structure, the top layer is a metal pattern layer, the middle layer is a photosensitive polyimide pattern layer, and the bottom layer is a polymer film support layer; wherein the area of the metal pattern layer is equal to the area of the photosensitive polyimide pattern layer, and is smaller than the area of the polymer film support layer.

[0136] Comparative Example 1: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof (no polyphenol hydroxyl graft on the molecular chain):

[0137] S1. Under a dry nitrogen atmosphere, 0.0520 mol of 2-(4-aminophenyl)-5-aminobenzimidazole and 0.0530 mol of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride were dissolved in 150 mL of an organic solvent and stirred at 0°C for 24 h, then 0.1100 mol of pyridine and 0.0600 mol of acetic anhydride were added, refluxed at 80°C for 1 h, then refluxed at 110°C for 5 h, cooled to room temperature, poured into 450 mL of methanol, then filtered, washed, and dried to obtain a photosensitive polyimide resin; the weight average molecular weight of the photosensitive polyimide resin was 2.6 x 10 5 g / mol, and the number average molecular weight was 1.8 x 10 5 g / mol;

[0138] The resulting product of the above step has the following formula:

[0139]

[0140] S2. Dissolve 12 g of high-temperature-resistant photosensitive polyimide resin in 105 g of N,N-dimethylformamide, after standing and degassing, spin coat the solution on a clean glass plate, and dry at 95°C to obtain a transparent film with a thickness of 25 μm;

[0141] S3. After the transparent film surface is cleaned, the entire film is immersed in a silver nitrate aqueous solution with a concentration of 0.005 mol / L to obtain a pretreated film C;

[0142] S4. 24 g of copper sulfate pentahydrate, 21 g of disodium ethylenediaminetetraacetate, and 8 mg of 2,2'-bipyridine are dissolved in 450 mL of deionized water to obtain a mixed solution;

[0143] S5. 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide are dissolved in 475 mL of deionized water, and then 450 mL of the mixed solution is added and stirred uniformly to obtain a chemical plating solution;

[0144] S6. After the pretreated film C is irradiated with ultraviolet light with a wavelength range of 254 nm on one side for 3 min, it is cleaned with pure water, then immersed in the chemical plating solution at 20°C for 5 min, and then cleaned with pure water and dried to obtain a polyimide flexible copper-clad plate C with a continuous metal layer plated on one side of the surface.

[0145] Comparative Example 2: Preparation of a high-temperature-resistant photosensitive polyimide resin and a transparent film and a method for selectively metallizing the surface thereof (less polyphenol hydroxyl grafting on the molecular chain):

[0146] S1. Under a dry nitrogen atmosphere, 0.0500 mol of 2-(4-aminophenyl)-5-aminobenzimidazole and 0.0510 mol of 3,3',4,4'-benzophenonetetracarboxylic dianhydride are dissolved in 150 mL of an organic solvent and stirred at 0°C for 24 h, then 0.1100 mol of pyridine and 0.0600 mol of propionic anhydride are added, refluxed at 80°C for 1 h, and then refluxed at 110°C for 5 h, cooled to room temperature, poured into 450 mL of methanol, and then filtered, washed, and dried to obtain a photosensitive polyimide resin; the weight average molecular weight of the photosensitive polyimide resin is 2.45 x 10 5 g / mol, and the number average molecular weight is 1.67 x 10 5 g / mol;

[0147] The product obtained in the above step has the following formula:

[0148]

[0149] S2: Under a dry nitrogen atmosphere, 5g of photosensitive polyimide resin was dissolved in 100mL of dimethyl sulfoxide. At 0℃, 1.6g of sodium hydride was added, and the mixture was stirred for 2 hours. Then, 0.05g of 4'-chloro-3,4-dihydroxybenzophenone was added, and the reaction was continued for 3 hours. The solution was then poured into 450mL of a mixed solution of dilute hydrochloric acid and methanol (pH 2). After filtration, washing, and drying, a high-temperature resistant photosensitive polyimide resin was obtained. The structural formula of the product obtained in the above steps is shown below:

[0150]

[0151] S3. Dissolve 5g of high-temperature resistant photosensitive polyimide resin in 105g of N,N-dimethylformamide. After standing and degassing, spin-coat the solution onto a clean glass plate and dry it at 95℃ to form a film with a thickness of 20μm.

[0152] S4. After cleaning the surface of the transparent film by removing oil, immerse it completely in a 0.005 mol / L silver nitrate aqueous solution to obtain the pretreated film C;

[0153] S5. Dissolve 24g of copper sulfate pentahydrate, 21g of disodium ethylenediaminetetraacetate and 8mg of 2,2'-bipyridine in 450mL of deionized water to obtain a mixed solution;

[0154] S6. Dissolve 8 mg of 2,2'-bipyridine, 70 mg of potassium ferrocyanide, 1 g of polyethylene glycol, 10 g of sodium potassium tartrate, 10 mL of formaldehyde aqueous solution, and 16 g of sodium hydroxide in 475 mL of deionized water, then add 450 mL of the mixture and stir until homogeneous to obtain the chemical plating solution.

[0155] S7. After irradiating the pretreated film C with ultraviolet light with a wavelength range of 200nm on one side for 3 minutes, it is cleaned with pure water, then immersed in a chemical plating solution at 20℃ for 5 minutes, and then cleaned and dried with pure water to obtain a polyimide flexible copper-clad laminate C with a continuous metal layer on one side.

[0156] Performance testing:

[0157] The infrared spectrum of the transparent film prepared in Example 1 was measured using a Fourier transform infrared spectrometer (FTIR, Nico-leti S50), with a resolution of 4 cm⁻¹. -1 The range is 4000-400cm -1 The number of scans was 32, and the test results are attached. Figure 2 As shown;

[0158] Determination of thermal stability:

[0159] The thermal stability of the samples was tested using a thermogravimetric analyzer (TGA, NETZSCH-Libra / 209F3). The sample mass was 5-10 mg, the temperature range was 30-800 °C, the purging gas was nitrogen, and the heating rate was 10 °C / min. The glass transition temperature (°C) of the transparent films prepared in Examples 1-6 and Comparative Examples 1-2 was also determined using this method.

[0160] Tensile strength test

[0161] Referring to GB / T1040.3-2006 "Test of Tensile Properties of Plastics", long strip specimens with a width of 15 mm, a length of 150 mm, and parallel lines with a spacing of 50 mm in the middle were prepared by cutting method. The tensile strength (MPa) of the transparent films prepared in Examples 1-6 and Comparative Examples 1-2 were tested at a speed of 10 mm / min using a universal testing machine (Instron 6800).

[0162] Determination of water absorption rate:

[0163] Referring to the ASTM-D570 standard "Test for water absorption of plastics", three test strips, each 5 cm long and 1 cm wide, were taken. Under standard atmospheric pressure, the length, width, thickness, and mass of the dry film were measured and recorded. The test strips were then immersed in deionized water at 23°C for 24 hours, and the length, width, thickness, and mass of the wet film were measured and recorded. The water absorption rate is the ratio of the difference between the wet film mass and the dry film mass to the dry film mass. The transparent films prepared in Examples 1-6 and Comparative Examples 1-2 were tested using an electronic balance (FA1104N, Shanghai Minqiao), and the average water absorption rate of each example and the three comparative examples was calculated as the water absorption rate (%) of the transparent film.

[0164] Metal coating adhesion test:

[0165] Referring to the national standard GB / T 9286-2021 "Paints and Varnishes - Cross-cut Test", three 5cm square metallized polyimide film samples were cut. Using a special tool, the metal layer on the film surface was cut at 1mm intervals along both the transverse and longitudinal directions, creating 100 square grids with sides of 1mm. All cuts should penetrate to the substrate surface but not cut through it. Finally, the adhesion of the metal coating was tested using special adhesive tape, and the adhesion results between the metal coating and the photosensitive polyimide surface were evaluated according to the test standards, as attached. Figure 5 As shown;

[0166] The measurement results are shown in Table 1;

[0167] Table 1

[0168]

[0169] Data analysis:

[0170] As can be seen from Table 1, the transparent film prepared by the present application has good thermal stability and mechanical properties, high light transmittance and low water absorption, the adhesion between the metal coating and the substrate reaches the highest level of ISO standard, and the adhesion of the coating is excellent; as can be seen from Comparative Examples 1 and 2, the transparent photosensitive polyimide resin prepared by the present application has photosensitivity, can realize surface metallization, but the adhesion of the metal coating is slightly poor if the small molecule halide is not grafted or the grafting amount is insufficient.

[0171] Those skilled in the art should understand that the discussion of the above any embodiment is only exemplary, and is not intended to imply that the scope of the present application is limited to these examples; under the idea of the present application, the above embodiments or technical features in different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for the sake of brevity.

[0172] The present application is intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any and all such modifications, variations, and equivalents that fall within the spirit and scope of the present application are intended to be included within the scope of the claims.

Claims

1. A high-temperature resistant photosensitive polyimide resin, characterized by comprising: The structure of the high-temperature resistant photosensitive polyimide resin is any one of the structures shown in formula (I), formula (II), and formula (III): Formula (I), Formula (II), Formula (Ⅲ); The preparation method of the high-temperature resistant photosensitive polyimide resin is as follows: Step A1. Under a dry nitrogen atmosphere, the diamine monomer and dianhydride monomer are dissolved in an organic solvent and reacted at 0-25℃ for 6-25h. Then, a catalyst and a dehydrating agent are added, and the mixture is refluxed at 80-100℃ for 1-3h, then refluxed at 110-120℃ for 3-6h, and then cooled to room temperature. The mixture is then poured into precipitant 1, filtered, washed, and dried to obtain photosensitive polyimide resin. Step A2. Under a dry nitrogen atmosphere, the photosensitive polyimide resin is dissolved in an organic solvent. Sodium hydride is added at 0-25°C and stirred for 1-3 hours. Then, a small molecule halogenated product is added and reacted for 3-6 hours. The mixture is then poured into precipitant 2, filtered, washed, and dried to obtain a high-temperature resistant photosensitive polyimide resin. The small molecule halogenated product is 4'-chloro-3,4-dihydroxybenzophenone or 3,4-dihydroxy-2'-chloroacetophenone; The molar ratio of diamine monomer, dianhydride monomer, catalyst, and dehydrating agent in step A1 is 0.05:0.051-0.06:0.11-5:0.06-10; the mass ratio of photosensitive polyimide resin, organic solvent, small molecule halogenated compound, and precipitant 2 in step A2 is 5:100-110:2.15-9.5:450-500. The molar ratio of the diamine monomer 2-(4-aminophenyl)-5-aminobenzimidazole and the diamine monomer 1,1-bis(4-aminophenyl)cyclohexane in the high-temperature resistant photosensitive polyimide resin of formula (II) is 4:

1. The molar ratio of the diamine monomer 2-(4-aminophenyl)-5-aminobenzimidazole and the diamine monomer 2,2'-bis(trifluoromethyl)diaminobiphenyl in the high-temperature resistant photosensitive polyimide resin of formula (III) is 4:

1.

2. A method for preparing the high-temperature resistant photosensitive polyimide resin according to claim 1: Step A1. Under a dry nitrogen atmosphere, the diamine monomer and dianhydride monomer are dissolved in an organic solvent and reacted at 0-25℃ for 6-25h. Then, a catalyst and a dehydrating agent are added, and the mixture is refluxed at 80-100℃ for 1-3h, then refluxed at 110-120℃ for 3-6h, and then cooled to room temperature. The mixture is then poured into precipitant 1, filtered, washed, and dried to obtain photosensitive polyimide resin. Step A2. Under a dry nitrogen atmosphere, the photosensitive polyimide resin is dissolved in an organic solvent. Sodium hydride is added at 0-25°C and stirred for 1-3 hours. Then, a small molecule halogenated product is added and reacted for 3-6 hours. The mixture is then poured into precipitant 2, filtered, washed, and dried to obtain a high-temperature resistant photosensitive polyimide resin.

3. A method for preparing the high-temperature-resistant photosensitive polyimide resin according to claim 2, characterized by, The molar ratio of diamine monomer, dianhydride monomer, catalyst and dehydrating agent in step A1 is 0.05:0.051-0.06:0.11-5:0.06-10; the mass ratio of photosensitive polyimide resin, organic solvent, small molecule halogenated compound and precipitant 2 in step A2 is 5:100-110:2.15-9.5:450-500.

4. A method of preparing the high-temperature-resistant photosensitive polyimide resin according to claim 2, characterized by, The organic solvent is any one of acetone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, phenol, benzonitrile, m-cresol, p-chlorophenol, p-chlorom-xylenol, and nitrobenzene. The catalyst is any one or more selected from pyridine, benzoic acid, p-hydroxybenzoic acid, quinoline, isoquinoline, triethylamine, and N,N-dimethylaniline; The dehydrating agent is any one or more of acetic anhydride, propionic anhydride, butyric anhydride, and phthalic anhydride; The precipitant 1 is any one or more of methanol, ethanol, and water; The precipitant 2 is dilute hydrochloric acid, and any one or more of methanol, ethanol, and water; The pH of the precipitant 2 is 1.0-3.

5.

5. A method for producing a transparent film, characterized by, Includes the following steps: The high-temperature resistant photosensitive polyimide resin described in claim 1 is dissolved in a solvent. After standing and degassing, the solution is spin-coated or scraped onto a clean glass plate and dried at 95-180°C to form a film, thus obtaining a transparent film.

6. The method for preparing a transparent film according to claim 5, characterized in that, The mass ratio of the high-temperature resistant photosensitive polyimide resin to the solvent is 5-15:50-120; the solvent is any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, butyrolactone, acetone, tetrahydrofuran, and m-cresol; the thickness of the polyimide wet film is 20-800 μm.

7. The application of the high-temperature resistant photosensitive polyimide resin according to claim 1 or the high-temperature resistant photosensitive polyimide resin prepared by the preparation method according to any one of claims 2-4, characterized in that, The high-temperature resistant photosensitive polyimide resin is used in flexible electronic device substrates, flexible display fields, or new energy battery composite current collector fields.

8. An application of a transparent film prepared by the preparation method according to any one of claims 5-6, characterized in that, The transparent film is used to prepare copper-coated polyimide films, supercapacitor electrode sheets, or composite current collectors for new energy batteries.

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