High-binding-force polyimide film and preparation method thereof

Abstract

The invention relates to the technical field of polyimide film preparation, and particularly discloses a high-binding-force polyimide film and a preparation method thereof.The preparation method comprises the steps that 1, novolac epoxy resin, copper phthalocyanine tetrasulfonate, a silane coupling agent and a diamine monomer are added into a polar solvent together; 2, gradually adding dianhydride monomers into the system, and reacting to obtain polyamide acid resin; and 3, carrying out defoaming, coating and solvent removal treatment on the polyamide acid resin to obtain a gel film, and carrying out imidization treatment on the gel film to obtain the polyimide film. The bonding strength of the polyimide film is kept to be 12 N / cm or above, is obviously superior to that of a polyimide film prepared through a traditional technology, and can be used in the field of FCCL.

Description

Technical Field

[0001] This invention relates to the field of polyimide film preparation technology, and in particular to a high-adhesion polyimide film and its preparation method. Background Technology

[0002] Polyimide films have excellent mechanical strength and good heat resistance, and are therefore widely used in automotive materials, microelectronics, aerospace and other fields.

[0003] With the development of the integrated circuit industry, the performance requirements for polyimide (PI) films are becoming increasingly stringent, and the copper adhesion of PI films is one of the core performance indicators of FCCL products. Conventional PI films used in flexible copper-clad laminates typically have a copper adhesion of only 7-9 N / cm, which is prone to poor adhesion and subsequent malfunctions. Traditional solutions often involve adding post-processing (high corona treatment, plasma roughening, etc.), which not only increases production costs but also leads to severe corona decay due to prolonged storage time or changes in ambient temperature and humidity, affecting the copper adhesion of the film. Therefore, producing PI films with high adhesion is of great significance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to propose a high-adhesion polyimide film and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a polyimide film includes the following steps:

[0007] Step 1: Add phenolic epoxy resin, copper tetrasulfonate phthalocyanine and silane coupling agent together with diamine monomer into a polar solvent;

[0008] Step 2: Gradually add dianhydride monomers to the above system to react and obtain polyamic acid resin;

[0009] Step 3: The polyamic acid resin is subjected to degassing, coating and desolventizing treatment to obtain a gel film, and the gel film is subjected to imidization treatment to obtain a polyimide film.

[0010] Preferably, in step one, the phenolic epoxy resin is selected from grade EPN-1138.

[0011] Preferably, in step one, the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0012] Preferably, in step one, the diamine is selected from one or more of 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodibenzophenone.

[0013] Preferably, in step one, the polar solvent is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0014] Preferably, in step two, the dianhydride is selected from one or more of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

[0015] Preferably, the solid components of the polyamic acid resin include the phenolic epoxy resin, the copper tetrasulfonate phthalocyanine, the silane coupling agent, the diamine, the dianhydride, and the polyamic acid generated by the reaction.

[0016] The amount of phenolic epoxy resin added accounts for 1%-10% of the mass of polyamic acid resin;

[0017] The amount of copper phthalocyanine tetrasulfonate added is 0.1-1% of the mass of the polyamic acid resin;

[0018] The amount of silane coupling agent added is 0.1-0.5% of the mass of polyamic acid resin;

[0019] The polyamic acid resin has a solid content of 15-20%.

[0020] Preferably, the polyamic acid resin has a viscosity of 100,000-200,000 mPa·s, and the solvent removal treatment temperature is 60-150℃ for 20-40 min.

[0021] Preferably, the imidization treatment temperature is 300-380℃ and the time is 20-30 min.

[0022] A polyimide film, obtained using the preparation method described above.

[0023] Preferably, the thickness of the polyimide film is 12.5 μm or 25 μm.

[0024] The above-mentioned application of a polyimide film in the production of flexible copper clad laminates.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention utilizes phenolic epoxy resin and the epoxy groups (—CH(O)CH—) in its molecular structure to undergo a ring-opening reaction with the carboxyl groups (—COOH) of the PI precursor (polyamic acid PAA), generating an ester crosslinking network. This not only achieves interfacial bonding between molecules and improves the heat resistance of the film after formation, but also further enhances the adhesion to the film surface. The introduced silane coupling agent further bridges the phenolic epoxy and PI matrix, hydrolyzing and condensing to form a Si-O-Si network, enhancing interfacial compatibility and improving the uniformity of film performance.

[0027] 2. Compared to polyimide films produced using traditional processes, the polyimide film prepared by this invention exhibits higher elongation at break, more regular internal molecular chains, and less tendency for internal stress to accumulate. Furthermore, the introduction of copper tetrasulfonate phthalocyanine not only releases Cu2+ to accelerate imidization but also strengthens intramolecular and intermolecular coordination bonds, further optimizing the chain segment structure and arrangement, resulting in more uniform chain segments. Therefore, the prepared polyimide film has a high modulus and exhibits more uniform and stable surface properties. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 The copper adhesion test curve of the polyimide film prepared in Example 1;

[0030] Figure 2 The copper adhesion test curve of the polyimide film prepared for Comparative Example 2. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This application provides a high-adhesion polyimide film and its preparation method, which solves the technical problem of insufficient copper adhesion in conventional polyimide films.

[0033] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0034] A method for preparing a polyimide film includes the following steps:

[0035] (1) Add phenolic epoxy resin, copper tetrasulfonate phthalocyanine and silane coupling agent together with diamine monomer to a polar solvent;

[0036] (2) Gradually add dianhydride monomers to the above system to obtain polyamic acid resin;

[0037] (3) The polyamic acid resin is subjected to degassing, coating and desolventizing treatment to obtain a gel film, and the gel film is subjected to imidization treatment to obtain a polyimide film.

[0038] The aforementioned phenolic epoxy resin is designated as EPN-1138.

[0039] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0040] Example 1

[0041] This embodiment provides a method for preparing a polyimide film, including the following steps:

[0042] (1) Add 180ml of DMAC (N,N-dimethylacetamide), 3.7g of phenolic epoxy resin, 0.4g of copper tetrasulfonate phthalocyanine, 0.15g of 3-aminopropyltriethoxysilane, 5.4g of PDA (p-phenylenediamine) and 10g of ODA (4,4'-diaminodiphenyl ether) to a 500ml glass flask, and stir thoroughly;

[0043] (2) 21.6g PMDA (pyromellitic dianhydride) was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 116,000 mPa·s was obtained.

[0044] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80℃ for 30 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 380℃ for 25 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated onto the film surface, and after pressing with copper foil, it was baked at high temperature. After removal and cooling, the copper bonding strength (peel strength) at 90° was tested. The test result curve is shown in the figure. Figure 1 As shown.

[0045] Example 2

[0046] This embodiment provides a method for preparing a polyimide film, including the following steps:

[0047] (1) Add 230ml of DMF (N,N-dimethylformamide), 0.5g of phenolic epoxy resin, 0.05g of copper tetrasulfonate phthalocyanine, 0.03g of 3-aminopropyltriethoxysilane, 10g of ODA (4,4'-diaminodiphenyl ether) and 11.1g of M-Tol (4,4'-diamino-2,2'-dimethylbiphenyl) to a 500ml glass flask and stir thoroughly.

[0048] (2) 21.7g PMDA was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 179,000 mPa·s was obtained.

[0049] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 110°C for 20 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 300°C for 30 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After cooling, the film was removed and the peel strength at 90°C was tested.

[0050] Example 3

[0051] This embodiment provides a method for preparing a polyimide film, comprising the following steps:

[0052] (1) Add 180ml NMP (N-methylpyrrolidone), 4g phenolic epoxy resin, 0.5g copper tetrasulfonate phthalocyanine, 0.3g γ-methacryloyloxypropyltrimethoxysilane, and 20g ODA to a 500ml glass flask and stir thoroughly.

[0053] (2) 21.7g PMDA was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 180,000 mPa·s was obtained.

[0054] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 40 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 380°C for 30 min to obtain a polyimide film with a thickness of 25 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After cooling, the film was removed and the peel strength at 90°C was tested.

[0055] Example 4

[0056] (1) Add 220ml of DMAC, 4g of phenolic epoxy resin, 0.3g of copper tetrasulfonate phthalocyanine, 0.1g of γ-glycidyl etheroxypropyltrimethoxysilane, 9.9g of DDM (4,4'-diaminodiphenylmethane) and 10g of ODA to a 500ml glass flask and stir thoroughly.

[0057] (2) 10.9 g PMDA and 14.7 g BPDA (3,3',4,4'-biphenyltetracarboxylic dianhydride) were gradually added to the above system. After the reaction was complete, a polyamic acid resin with a viscosity of 150,000 mPa·s was obtained.

[0058] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 40 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 380°C for 20 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After cooling, the film was removed and the peel strength at 90°C was tested.

[0059] Example 5

[0060] (1) Add 220ml of DMAC, 3g of phenolic epoxy resin, 0.2g of copper tetrasulfonate phthalocyanine, 0.08g of 3-aminopropyltriethoxysilane, 5.4g of PDA and 10g of ODA to a 500ml glass flask and stir thoroughly.

[0061] (2) 6.2g ODPA (3,3',4,4'-diphenyl ether tetracarboxylic dianhydride) and 17.3g PMDA were gradually added to the above system. After the reaction was complete, a polyamic acid resin with a viscosity of 180,000 mPa·s was obtained.

[0062] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 40 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, and placed in an imidization furnace at 350°C for 25 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated on the film surface, and after pressing with copper foil, it was baked at high temperature. After being removed and cooled, the peel strength at 90° was tested.

[0063] Comparative Example 1

[0064] This comparative example provides a conventional process for preparing polyimide films, including the following steps:

[0065] (1) Add 180ml of DMAC, 5.4g of PDA and 10g of ODA to a 500ml glass flask and stir thoroughly;

[0066] (2) 21.6 g PMDA was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 115,000 mPa·s was obtained.

[0067] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 30 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 380°C for 25 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After removal and cooling, the peel strength at 90° was tested. The test result curve is shown in the figure. Figure 2 As shown.

[0068] Comparative Example 2

[0069] This comparative example provides a conventional process for preparing polyimide films, including the following steps:

[0070] (1) Add 230ml of DMF, 10g of ODA and 11.1g of M-Tol to a 500ml glass flask and stir thoroughly;

[0071] (2) 21.7g PMDA was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 178,000 mPa·s was obtained.

[0072] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 30 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 300°C for 30 min to obtain a polyimide film with a thickness of 12.5 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After cooling, the film was removed and the peel strength at 90°C was tested.

[0073] Comparative Example 3

[0074] This comparative example provides a conventional process for preparing polyimide films, including the following steps:

[0075] (1) Add 180ml NMP and 20g ODA to a 500ml glass flask and stir thoroughly;

[0076] (2) 21.7g PMDA was gradually added to the above system, and after the reaction was complete, a polyamic acid resin with a viscosity of 180,000 mPa·s was obtained.

[0077] (3) The polyamic acid resin was subjected to vacuum degassing treatment, then coated onto a glass plate and dried in a forced-air drying oven at 80°C for 40 min to obtain a gel film. The obtained gel film was peeled off and fixed onto a metal frame, then placed in an imidization furnace and imidized at 380°C for 30 min to obtain a polyimide film with a thickness of 25 μm. Epoxy adhesive was coated onto the film surface, and the film was pressed with copper foil and baked at high temperature. After cooling, the film was removed and the peel strength at 90°C was tested.

[0078] Table 1. Performance testing methods for polyimide films

[0079] performance Copper cladding adhesion (peel strength) Test methods GB / T 13555-2017

[0080] Table 2 shows the test results of the copper adhesion of the polyimide film.

[0081] performance Peel strength unit N / cm Example 1 13.5 Example 2 13.7 Example 3 16.2 Example 4 12.7 Example 5 14.1 Comparative Example 1 7.9 Comparative Example 2 7.6 Comparative Example 3 8.7

[0082] As shown in Table 2, the polyimide film prepared by the method of this invention maintains a bonding strength of over 12 N / cm. The bonding strength of the polyimide film prepared by this invention is significantly better than that of polyimide films prepared by traditional processes, and it can meet the requirements for use in the FCCL field. The preparation method of this invention is simple to operate, highly feasible, and has a significant improvement effect on the bonding strength of the film, and has potential application value in the field of industrial production.

[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyimide film, characterized in that, Includes the following steps: Step 1: Add phenolic epoxy resin, copper tetrasulfonate phthalocyanine and silane coupling agent together with diamine monomer into a polar solvent; Step 2: Gradually add dianhydride monomers to the above system to react and obtain polyamic acid resin; Step 3: The polyamic acid resin is subjected to degassing, coating and desolventizing treatment to obtain a gel film, and the gel film is subjected to imidization treatment to obtain a polyimide film.

2. The method for preparing a polyimide film according to claim 1, characterized in that, In step one, the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

3. The method for preparing a polyimide film according to claim 1, characterized in that, In step one, the diamine is selected from one or more of 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodibenzophenone.

4. The method for preparing a polyimide film according to claim 1, characterized in that, In step one, the polar solvent is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

5. The method for preparing a polyimide film according to claim 1, characterized in that, In step two, the dianhydride is selected from one or more of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

6. The method for preparing a polyimide film according to claim 1, characterized in that, The solid components of the polyamic acid resin include the phenolic epoxy resin, the copper tetrasulfonate phthalocyanine, the silane coupling agent, the diamine, the dianhydride, and the polyamic acid generated by the reaction. The amount of phenolic epoxy resin added accounts for 1%-10% of the mass of polyamic acid resin; The amount of copper phthalocyanine tetrasulfonate added is 0.1-1% of the mass of the polyamic acid resin; The amount of the silane coupling agent added is 0.1-0.5% of the mass of the polyamic acid resin; The polyamic acid resin has a solid content of 15-20%.

7. The method for preparing a polyimide film according to claim 1, characterized in that, The viscosity of the polyamic acid resin is 100,000-200,000 mPa·s, and the solvent removal treatment temperature is 60-150℃, with a time of 20-40 min.

8. The method for preparing a polyimide film according to claim 1, characterized in that, The imidization treatment is performed at a temperature of 300-380℃ for 20-30 minutes.

9. A polyimide film, characterized in that, Obtained using the preparation method described in any one of claims 1-8.

10. The application of the polyimide film according to claim 9 in the production of flexible copper clad laminates.

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