A polyamide-imide adhesive, a polyimide screen membrane and a preparation method and application thereof

Abstract

The application provides a kind of polyamide-imide adhesive, polyamide-imide screen film and its preparation method and application, the material of the polyamide-imide adhesive includes polyamide-imide resin, epoxy resin and toughening resin, the polyamide-imide adhesive obtained by matching the above three resins has excellent solvent resistance and chemical resistance, the adhesive layer of the polyamide screen film made of the polyamide base film further matched with the polyamide-imide adhesive is non-tacky, which is convenient for positioning on the screen, and can be stored at room temperature, and since the polyamide-imide resin and the polyamide base film have the same absorption band of ultraviolet laser, the addition of ultraviolet absorber is not required to achieve better laser effect, so that the printing screen made of the polyamide screen film has the advantages of high laser etching precision and fast efficiency.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a polyamide-imide adhesive, a polyimide screen film, its preparation method, and its application. Background Technology

[0002] Traditional printing screens use photosensitive inks coated on stainless steel mesh, and then the desired lines are obtained through exposure and development. However, traditional printing screen processes cause significant pollution, have a short lifespan, and require frequent screen replacements, which affects production efficiency and increases production costs.

[0003] To address the aforementioned problems of traditional screen printing, researchers have proposed a composite film structure using polyimide film and epoxy or polyurethane adhesives.

[0004] CN112778937A discloses an epoxy adhesive, a cover film, and a printing stencil. The epoxy adhesive, by weight percentage, comprises the following components: 20-60% epoxy resin, 20-40% film-forming resin, 5-20% tackifying resin, 1-20% curing agent, and 0.1-2% curing accelerator. This invention, through improvements to the adhesive formulation and the cover film, enables the cover film to be molded at low temperatures. Furthermore, the cover film exhibits good adhesion to the stencil body, is less prone to adhesive overflow and delamination, and possesses excellent chemical resistance.

[0005] CN114479732A discloses an epoxy adhesive, a polyimide cover film, and a printing screen. The epoxy adhesive comprises 45-60% epoxy resin, 15-30% tackifying resin, 20-30% film-forming resin, 0.5-1.5% UV absorber, and 0.2-1% curing accelerator by mass. The tackifying resin includes at least rosin resin and phenolic resin. When the polyimide cover film of this invention is laser-cut on the printing screen, the cutting gradient between the polyimide film and the adhesive layer is small, resulting in a finer circuit pattern. This effectively extends the service life of the printing screen, saves material costs, and reduces changeover time on the production line.

[0006] CN111605300A discloses a polyimide solar screen and its preparation method, which includes the following steps: (1) Stretching and laminating: First, stretch the polyester wire mesh, and after standing, fix the polyester wire mesh on the frame to form a polyester mesh. Then, use hot melt adhesive film to laminate the metal wire mesh to the composite area in the middle of the polyester mesh to form a composite mesh. Fix the composite mesh to another frame to obtain a composite white screen; (2) Coating the adhesive layer: Coat the surface of the composite white screen or the polyimide film evenly with the adhesive to form an adhesive layer; (3) Laminating: Take a polyimide film of the corresponding size and thickness and lay it flat in the coating area of ​​the composite white screen. Then, place the composite white screen flat on the heating platform. The area of ​​the heating platform is equal to the area of ​​the composite white screen. The temperature is 70-130℃. Then, use 1-10 kg of pressure to press the polyimide film and the composite white screen together to form a polymer composite layer on the composite white screen; (4) Drying; (5) Laser engraving; (6) Cleaning, inspection and packaging.

[0007] However, research has found that the solvent resistance of the screen printing cover film provided in the prior art, including the invention mentioned above, is generally poor, and the number of times the screen can be used cannot exceed 200,000. Furthermore, since the epoxy or polyurethane adhesives used absorb laser light in the infrared region, which is different from the absorption band of the polyimide-based film, an additional ultraviolet absorber needs to be added to achieve a better laser effect.

[0008] Therefore, in order to solve the above-mentioned technical problems, it is urgent to develop a polyamide-imide adhesive with excellent solvent resistance and without the need for additional ultraviolet light absorbers. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a polyamide-imide adhesive, a polyamide screen film, its preparation method, and its applications. The polyamide-imide adhesive is insoluble in silver paste or similar organic solvents, exhibits excellent solvent resistance, and has the same absorption band for ultraviolet lasers as the polyimide-based film (approximately 355 nm). Therefore, it can achieve superior laser etching effects without the need for additional ultraviolet absorbers. Consequently, the polyamide screen film made using it has the advantages of high laser etching precision and high efficiency.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a polyamide-imide adhesive, wherein the polyamide-imide adhesive comprises the following components in parts by weight:

[0012] 50-90 parts by weight of polyamide-imide resin;

[0013] 1-20 parts by weight of epoxy resin;

[0014] 5 to 40 parts by weight of toughening resin.

[0015] The polyamide-imide resin can be 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, or 85 parts by weight, etc.

[0016] The epoxy resin can be 2 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, or 18 parts by weight, etc.

[0017] The toughening resin can be 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, or 35 parts by weight, etc.

[0018] This invention uses polyamide-imide resin as the main resin, combined with epoxy resin and toughening resin, to obtain a polyamide-imide adhesive with excellent solvent resistance and chemical resistance. Furthermore, the adhesive layer of the polyamide screen printing film made from the polyamide-based film is non-contact, facilitating positioning on the screen and exhibiting excellent solvent resistance, allowing for storage at room temperature. Simultaneously, since the polyamide-imide resin and the polyimide-based film have the same absorption band for ultraviolet laser (355nm), a superior laser effect can be achieved without the need for additional ultraviolet absorbers. This results in printing screens made from the polyamide screen printing film possessing advantages such as high laser etching precision and high efficiency.

[0019] Preferably, the glass transition temperature (Tg) of the polyamide-imide resin is 130–200°C, such as 140°C, 150°C, 160°C, 170°C, 180°C, or 190°C.

[0020] Preferably, the viscosity of the polyamide-imide resin is 0.5 to 10 Pa·s (25°C), such as 1 Pa·s, 2 Pa·s, 3 Pa·s, 4 Pa·s, 5 Pa·s, 6 Pa·s, 7 Pa·s, 8 Pa·s or 9 Pa·s.

[0021] In this invention, the polyamide-imide resin can be specifically selected from Mitsubishi's T065, Toyobo's HR-71DD, or Shangda's D400.

[0022] Preferably, the epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic resin, o-cresol phenolic resin, bisphenol A phenolic resin, or phenol-biphenyl type epoxy resin.

[0023] In this invention, the epoxy resin can be any two or more of the following: Bisphenol A epoxy resin SQAN203 and SQAN201 from Shandong Shengquan, Bisphenol A type epoxy resin EP4910P2 from Aidi Ke, and Phenolic epoxy resin N740S from Wuxi Lanxing.

[0024] Preferably, the toughening resin includes any one or a combination of at least two of the following: nitrile rubber, carboxyl-modified nitrile rubber, epoxy-modified nitrile rubber, phenoxy resin, carboxyl-modified phenoxy resin, epoxy-modified phenoxy resin, acrylate rubber, carboxyl-modified acrylate rubber, epoxy-modified acrylate rubber, ethylene acrylate rubber, carboxyl-modified ethylene acrylate rubber, or epoxy-modified ethylene acrylate rubber.

[0025] In this invention, the toughening resin may specifically be JSR's nitrile rubber XER-32, Huntsman's nitrile rubber RK84L, or Nippon Steel & Sumitomo Metal Corporation's phenoxy resin YP50.

[0026] Preferably, the polyamide-imide adhesive further comprises a polar organic solvent.

[0027] Preferably, the polar organic solvent includes any one or a combination of at least two of dimethylformamide, dimethylacetamide, or N-methylpyrrolidone.

[0028] Preferably, the mass ratio of the polyamide-imide resin, epoxy resin, and toughening resin to the polar organic solvent is 1:(2-9), for example, 1:3, 1:4, 1:5, 1:6, 1:7, or 1:8.

[0029] In a second aspect, the present invention provides a polyimide screen printing film, the polyimide screen printing film comprising a polyimide base film, a polyamide-imide adhesive layer and a release film arranged sequentially therefrom;

[0030] The raw materials for the polyamide-imide adhesive layer include the polyamide-imide adhesive as described in the first aspect.

[0031] Preferably, the thickness of the polyimide-based film is 1 to 10 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or 9 μm.

[0032] Preferably, the thickness of the polyamide-imide adhesive layer is 1 to 10 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or 9 μm.

[0033] Thirdly, the present invention provides a method for preparing a polyimide screen printing film as described in the second aspect, the method comprising: coating a polyamide-based film with a polyamide-imide adhesive as described in the first aspect, drying and then attaching a release film to obtain the polyimide screen printing film.

[0034] Preferably, the drying temperature is 80-150°C, such as 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C.

[0035] Preferably, the drying time is 2 to 5 minutes, such as 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes or 4.5 minutes.

[0036] Preferably, the pressure of attaching the release film is 0.1 to 0.5 MPa, for example, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa or 0.45 MPa.

[0037] Fourthly, the present invention provides a printing screen prepared using a polyimide screen film as described in the second aspect.

[0038] Fifthly, the present invention provides a method for preparing a printing screen as described in the fourth aspect, the method comprising: removing the release film of a polyimide screen film as described in the second aspect and bonding it to one side of a stainless steel screen film, and then subjecting it to hot pressing and ultraviolet laser engraving to obtain the printing screen film.

[0039] Preferably, the hot pressing temperature is 150-200°C, such as 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, or 195°C.

[0040] Preferably, the pressure of the hot pressing is 0.5 to 3 MPa, such as 0.7 MPa, 0.9 MPa, 1.1 MPa, 1.3 MPa, 1.5 MPa, 1.7 MPa, 1.9 MPa, 2.3 MPa, 2.6 MPa or 2.9 MPa.

[0041] Preferably, the hot pressing time is 10 to 30 minutes, such as 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes, or 28 minutes.

[0042] In a sixth aspect, the present invention provides the application of a polyamide-imide adhesive as described in the first aspect in a printing screen.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The polyamide-imide adhesive provided by this invention comprises polyamide-imide resin, epoxy resin, and toughening resin. The combination of these three resins results in a polyamide-imide adhesive with excellent solvent and chemical resistance. Furthermore, when combined with a polyamide-based film, the adhesive layer of the polyamide screen printing film is non-contact, facilitating positioning on the screen and allowing for storage at room temperature. Simultaneously, since the polyamide-imide resin and the polyamide-based film have the same absorption band for ultraviolet lasers, a superior laser effect can be achieved without the need for additional ultraviolet absorbers. This results in printing screens made using the polyamide screen printing film exhibiting advantages such as high laser etching precision and high efficiency. Attached Figure Description

[0045] Figure 1 This is a schematic cross-sectional view of the polyimide screen film provided by the present invention.

[0046] Among them, 1-polyimide-based film, 2-polyamide-imide adhesive layer, and 3-release film. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0048] The following is some information about the raw materials involved in the specific embodiments of the present invention:

[0049] Polyamide-imide (PAI) resin: selected from Toyobo's HR-71DD, Mitsubishi's T065 or Dongguan Shangda's D400;

[0050] Epoxy resin: Selected from Wuxi Lanxing's phenolic epoxy resin N740S, Shandong Shengquan's bisphenol A phenolic epoxy resin SQAN203, SQAN201 or Aidi Ke's bisphenol A type epoxy resin EP4910P2.

[0051] Nitrile rubber: Selected from JSR's XER-32 or Huntsman's RK84L;

[0052] Phenoxy resin: Nippon Steel & Sumitomo Metal Corporation's YP50.

[0053] Example 1

[0054] A polyamide-imide adhesive, comprising the following components by weight:

[0055]

[0056] The preparation method of the polyamide-imide adhesive provided in this embodiment includes: mixing PAI resin HR-71DD, phenolic epoxy resin N740S and nitrile rubber XER-32 uniformly in N,N-dimethylformamide to obtain the polyamide-imide adhesive.

[0057] Example 2

[0058] A polyamide-imide adhesive, comprising the following components by weight:

[0059]

[0060] The preparation method of the polyamide-imide adhesive provided in this embodiment includes: mixing PAI resin HR-71DD, bisphenol A phenolic epoxy resin SQAN201 and nitrile rubber RK84L uniformly in N,N-dimethylformamide to obtain the polyamide-imide adhesive.

[0061] Example 3

[0062] A polyamide-imide adhesive, comprising the following components by weight:

[0063]

[0064]

[0065] The preparation method of the polyamide-imide adhesive provided in this embodiment includes: mixing PAI resin D400, bisphenol A type epoxy resin EP4910P2 and nitrile rubber XER-32 uniformly in N,N-dimethylformamide to obtain the polyamide-imide adhesive.

[0066] Example 4

[0067] A polyamide-imide adhesive, comprising the following components by weight:

[0068]

[0069] The preparation method of the polyamide-imide adhesive provided in this embodiment includes: mixing PAI resin HR-71DD, phenolic epoxy resin N740S and nitrile rubber XER-32 uniformly in N,N-dimethylformamide to obtain the polyamide-imide adhesive.

[0070] Example 5

[0071] A polyamide-imide adhesive differs from Example 1 only in that Mitsubishi's PAI resin T065 is used instead of PAI resin HR-71DD, while the other components, dosages, and preparation methods are the same as in Example 1.

[0072] Example 6

[0073] A polyamide-imide adhesive differs from Example 1 only in that bisphenol A phenolic epoxy resin SQAN203 is used instead of phenolic epoxy resin N740S, while the other components, dosages, and preparation methods are the same as in Example 1.

[0074] Example 7

[0075] A polyamide-imide adhesive differs from Example 1 only in that phenoxy resin YP50 is used instead of nitrile rubber XER-32, while the other components, dosages, and preparation methods are the same as in Example 1.

[0076] Comparative Example 1

[0077] A polyamide-imide adhesive differs from Example 1 only in that the amount of PAI resin HR-71DD added is 20 parts by weight, while the other components, amounts, and preparation methods are the same as in Example 1.

[0078] Comparative Example 2

[0079] A polyamide-imide adhesive differs from Example 1 only in that the amount of PAI resin HR-71DD added is 300 parts by weight, while the other components, amounts, and preparation methods are the same as in Example 1.

[0080] Comparative Example 3

[0081] A polyamide-imide adhesive differs from Example 1 only in that phenolic epoxy resin N740S is not added; all other components, dosages, and preparation methods are the same as in Example 1.

[0082] Comparative Example 4

[0083] A polyamide-imide adhesive differs from Example 1 only in that it does not contain nitrile rubber XER-32; all other components, dosages, and preparation methods are the same as in Example 1.

[0084] Application Example 1

[0085] A printing screen, the preparation method of which includes the following steps:

[0086] (1) The polyamide-imide adhesive (Example 1) was coated on the corona surface of the polyimide-based film, dried at 130°C for 5 min, and then the release paper was bonded at 60°C and 0.4 MPa to obtain the polyimide screen film.

[0087] (2) Tear off the release film on the polyimide screen film obtained in step (1), attach the polyamide-imide adhesive layer to one side of the stainless steel screen, press it in a hot press at 180°C and 0.8MPa for 30 minutes, and finally cut out the lines by ultraviolet laser to obtain the printing screen.

[0088] A schematic diagram of the cross-sectional structure of the polyimide screen film obtained in step (1) is shown below. Figure 1 As shown, it includes a polyimide-based film (5 μm thick), a polyamide-imide adhesive layer (5 μm thick), and a release film arranged sequentially.

[0089] Application Examples 2-7

[0090] A printing screen, which differs from Application Example 1 only in that the polyamide-imide adhesive obtained in Examples 2-7 is used instead of the polyamide-imide adhesive obtained in Example 1, while other materials and process parameters are the same as in Application Example 1.

[0091] Comparative Application Examples 1-4

[0092] A printing screen, which differs from Application Example 1 only in that the polyamide-imide adhesive obtained in Comparative Examples 1 to 4 is used instead of the polyamide-imide adhesive obtained in Example 1, while other materials and process parameters are the same as in Application Example 1.

[0093] Performance testing:

[0094] (1) Adhesion strength: After hot pressing the polyimide mesh and the stainless steel mesh, cut them into 10mm strips and peel them at 180° at a speed of 100mm / min.

[0095] (2) Adhesion: Before hot pressing, the polyamide-imide adhesive layer of the polyimide screen film with the release film removed is attached to the screen. If there is no adhesion at room temperature, or if the polyamide-imide adhesive layer can move freely when attached to the screen, it means that the adhesion is OK; otherwise, the adhesion is NG.

[0096] (3) Chemical resistance: Immerse the printing screen in silver paste for 24 hours, then wipe it dry. Observe under a microscope whether the silver paste has penetrated between the polyimide base film and the polyamide-imide adhesive layer, or whether there are bulges or delamination between the polyamide-imide adhesive layer and the screen. If it occurs, it is NG; if it does not occur, it is OK.

[0097] (4) Excess glue amount: Use a 10mm diameter punch to punch 5 holes in the polyimide screen film, and then hot press it with the screen at a temperature of 180℃ and a pressure of 0.8MPa for 30 minutes. Use a microscope to measure the amount of excess glue overflowing from the holes.

[0098] (5) Room temperature storage performance: If the performance of the polyimide screen film can still be maintained above the specification value after being placed at room temperature for 6 months, then the room temperature storage performance is OK.

[0099] (6) Etching gradient: The opening width of the polyimide film surface in the printing screen is L1 when observed under a microscope. Then, the printing screen is flipped over and the opening width of the polyamide-imide adhesive layer at the same location is L2. The difference between the opening widths of the polyimide film surface and the polyamide-imide adhesive layer, L1-L2, is the etching gradient.

[0100] (7) Service life: Pour paste into one end of the printing screen with the laser-etched pattern, apply a certain pressure to the paste area of ​​the screen with a squeegee, and move it towards the other end of the screen. When the squeegee has scraped the entire printing area, lift it up, and the screen will also detach from the substrate. The paste will be gently scraped back to the initial position by the ink return knife, and the worktable will return to the loading position. This completes one printing cycle. The printing parameters are: squeegee angle is 55°, squeegee hardness is 75A, screen spacing printing pressure is 55N, printing speed is 230mm / s, and the number of times the pattern is printed until abnormalities such as false printing, broken lines, screen blockage, paste leakage, and damage or delamination of the cover film are found is the service life of the printing screen.

[0101] The tests were conducted according to the test methods described above, corresponding to test cases 1-7 and the printing screens provided in comparative application examples 1-4. The test results are shown in Table 1.

[0102] Table 1

[0103]

[0104]

[0105] According to the data in Table 1:

[0106] The bonding strength between the polyimide screen film and the stainless steel screen provided in Application Examples 1 to 7 is 8.1 to 10.2 N / cm, the tack and chemical resistance are all qualified, the amount of excess adhesive is 0.02 to 0.05 mm, the room temperature storage box is qualified, the etching gradient is 4.7 to 5.0, and the service life is as high as 290,000 to 350,000 cycles.

[0107] Compared to Application Example 1, the amount of PAI resin added to the polyamide-imide adhesive used in Application Example 1 was too low, resulting in substandard tack and chemical resistance of the polyimide screen film, excessive adhesive overflow, and a short service life. In contrast, the amount of PAI resin added to the polyamide-imide adhesive used in Application Example 2 was too low, resulting in low bonding strength between the polyimide screen film and the stainless steel mesh, which did not meet the usage requirements.

[0108] Compared with Application Example 1, the polyamide-imide adhesive used in Comparative Application Example 3 did not contain phenolic epoxy resin, resulting in lower bonding strength between the polyimide screen film and the stainless steel mesh, and excessive adhesive overflow.

[0109] Compared to Application Example 1, the polyamide-imide adhesive used in Comparative Application Example 4 did not contain nitrile rubber, resulting in higher bonding strength between the polyimide screen film and the stainless steel mesh, but also excessive adhesive overflow and a shorter service life.

[0110] The applicant declares that this invention illustrates a polyamide-imide adhesive, a polyimide screen printing film, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A polyimide screen printing film for printing screens, characterized in that, The polyimide screen film comprises a polyimide-based film, a polyamide-imide adhesive layer, and a release film arranged sequentially. The polyamide-imide adhesive comprises the following components in parts by weight: 50-90 parts by weight of polyamide-imide resin; 1-20 parts by weight of epoxy resin; 5-40 parts by weight of toughening resin; The polyamide-imide resin and the polyimide-based film have the same absorption band for ultraviolet laser.

2. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The glass transition temperature of the polyamide-imide resin is 130~200℃.

3. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The viscosity of the polyamide-imide resin is 0.5~10 Pa·s.

4. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic resin, o-cresol resin, bisphenol A resin, or phenol-biphenyl type epoxy resin.

5. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The toughening resin includes any one or a combination of at least two of the following: nitrile rubber, carboxyl-modified nitrile rubber, epoxy-modified nitrile rubber, phenoxy resin, carboxyl-modified phenoxy resin, epoxy-modified phenoxy resin, acrylate rubber, carboxyl-modified acrylate rubber, epoxy-modified acrylate rubber, ethylene acrylate rubber, carboxyl-modified ethylene acrylate rubber, or epoxy-modified ethylene acrylate rubber.

6. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The polyamide-imide adhesive also includes a polar organic solvent in its material.

7. The polyimide screen printing film for printing screens according to claim 6, characterized in that, The polar organic solvent includes any one or a combination of at least two of dimethylformamide, dimethylacetamide, or N-methylpyrrolidone.

8. The polyimide screen printing film for printing screens according to claim 6, characterized in that, The mass ratio of the total of the polyamide-imide resin, epoxy resin, and toughening resin to the polar organic solvent is 1:(2~9).

9. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The thickness of the polyimide-based film is 1~10 μm.

10. The polyimide screen printing film for printing screens according to claim 1, characterized in that, The thickness of the polyamide-imide adhesive layer is 1~10 μm.

11. A method for preparing a polyimide screen printing film for printing screens as described in any one of claims 1-10, characterized in that, The preparation method includes: coating the polyamide-imide adhesive onto a polyimide-based film, drying it, and then attaching a release film to obtain the polyimide screen film.

12. The preparation method according to claim 11, characterized in that, The drying temperature is 80~150℃.

13. The preparation method according to claim 11, characterized in that, The drying time is 2-5 minutes.

14. The preparation method according to claim 11, characterized in that, The pressure for attaching the release film is 0.1~0.5MPa.

15. A printing screen, characterized in that, The printing screen is prepared using the polyimide screen film as described in any one of claims 1-10.

16. A method for preparing a printing screen as described in claim 15, characterized in that, The preparation method includes: peeling off the release film of the polyimide screen printing film as described in any one of claims 1-10, bonding it to one side of a stainless steel screen printing film, and then obtaining the printing screen printing film by hot pressing and ultraviolet laser engraving.

17. The preparation method according to claim 16, characterized in that, The hot pressing temperature is 150~200℃.

18. The preparation method according to claim 16, characterized in that, The pressure of the hot pressing is 0.5~3 MPa.

19. The preparation method according to claim 16, characterized in that, The hot pressing time is 10~30 min.

Images