A method for preparing a polyetherimide film with low dielectric loss

Abstract

This invention belongs to the field of polymer materials technology. It provides a method for preparing a low-dielectric-loss polyetherimide film. The method involves dissolving polyetherimide (PEI) in a polar solvent to obtain a polyetherimide matrix solution, mixing a photosensitive prepolymer and a photoinitiator to obtain a UV-curable mixture system, blending the polyetherimide matrix solution with the UV-curable mixture system to obtain a UV-PEI casting solution, coating the UV-PEI casting solution into a film, and then performing gradient UV curing. This method restricts the relaxation of the polyetherimide molecular chains, achieving low-temperature, high-efficiency film formation and dielectric property control, reducing dielectric loss, increasing the dielectric constant of the film, and improving the breakdown strength and charge-discharge efficiency at high temperatures and high fields.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a method for preparing a polyetherimide film, which is applicable to flexible electronic devices, high-frequency circuit packaging, and energy storage devices. Background Technology

[0002] Traditional polyetherimide (PEI) film preparation relies on high-temperature melt extrusion or solvent evaporation to form films, which has problems such as high energy consumption, poor thickness uniformity, and difficulty in functional modification.

[0003] Conventional dielectric films, such as polyimide and polyetherimide, have low dielectric constants (<4.0) and their dielectric loss increases significantly at high temperatures, making them difficult to meet the requirements of 5G high-frequency communication.

[0004] The monomer unit of polyetherimide is composed of carbonyl, aromatic imine ring and ether bond. Due to the presence of carbonyl and ether bond, PEI exhibits polarity. The movement of local chain segments in the polymer molecular chain will cause β relaxation of PEI. This secondary relaxation phenomenon will cause a sharp increase in dielectric loss.

[0005] Ultraviolet (UV) curing technology can restrict the movement of local segments in polymer molecular chains, causing their movement to be bound and hindered, forming a cross-linked network structure, thereby limiting molecular chain relaxation. However, since UV curing technology is mostly used for acrylate systems, polyetherimide (PEI) is difficult to directly adapt to UV processes due to its high glass transition temperature (Tg≈217℃) and low photoreactivity. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing a low-dielectric-loss polyetherimide film. This method restricts the relaxation of the polyetherimide molecular chain, achieving low-temperature and efficient film formation and dielectric property control, reducing dielectric loss, increasing the dielectric constant of the film, and improving the breakdown strength and charge / discharge efficiency at high temperatures and high fields.

[0007] The purpose of this invention is to provide a method for preparing a low dielectric loss polyetherimide film, comprising the following steps: (1) Dissolve polyetherimide in a solvent to obtain a polyetherimide matrix solution; (2) The photosensitive prepolymer and the photoinitiator are mixed to obtain a UV-curable hybrid system; (3) The above polyetherimide matrix solution is blended with the UV curing mixture to obtain UV-PEI casting solution, and the UV-PEI casting solution is coated into a film; (4) The membrane obtained in step (3) is subjected to gradient ultraviolet light curing to obtain a polyetherimide membrane with low dielectric loss.

[0008] The preparation method of this invention involves mixing a UV-curable mixture system with a polyetherimide matrix solution to obtain a UV-PEI casting liquid composite system. The photosensitive prepolymer introduced into the composite system is cross-linked by UV curing, which restricts the relaxation of the polyetherimide molecular chain, reduces the glass transition temperature, increases the dielectric constant of the film, and reduces the dielectric loss.

[0009] Furthermore, in step (2), the UV-curable mixture system also includes monomers, and the functional groups in the monomers include at least one of carbon-carbon double bonds and hydroxyl groups.

[0010] This invention modulates the polarity of components in a UV-curable system by using monomers to increase their polarity and enhance their hydrogen bonding with PEI (e.g., -OH forms hydrogen bonds with the C=O of PEI), thereby improving the compatibility of the two-component casting solution system.

[0011] Further, in step (4), gradient ultraviolet curing includes the following steps: The first stage involves irradiating the film surface with a UV light source of 300-375 nm and an intensity of 50-100 mW / cm² for 10-60 seconds to induce cross-linking. The second stage involves irradiating the interior with a UV light source of 375-395 nm and an intensity of 100-150 mW / cm² at 60-100℃ for 30-120 seconds to achieve deep curing.

[0012] Further, in step (4), the cured polyetherimide (PEI) film is post-treated. The post-treatment steps include pre-drying at a gradient temperature of 60~100 ℃ for 3~8 min to remove some of the solvent.

[0013] The post-processing steps also include heat-treating the pre-dried PEI film at temperatures of 160~200℃ and 120~250℃ respectively to remove residual solvent, and then stretching it appropriately with a stretching ratio of 1.5~1.9. The post-processing yields a PEI film with high dielectric constant, low loss, and flexibility.

[0014] Furthermore, the photosensitive prepolymer includes at least one of polyurethane acrylate (PUA) prepolymer, polyester acrylate (PEA) prepolymer, epoxy acrylate (EA) prepolymer, and silicone-modified acrylate (Siloxane PUA) prepolymer.

[0015] Preferably, the photosensitive prepolymer includes at least one selected from polycaprolactone polyurethane acrylate, polyethylene terephthalate acrylate, bisphenol A epoxy acrylate, and silane-terminated polyurethane acrylate. More preferably, the photosensitive prepolymer is polycaprolactone polyurethane acrylate.

[0016] Further, the photoinitiator includes at least one selected from 2-hydroxy-2-methylphenylacetone (1173), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), and 3-coumarinone derivatives (LFC3260). Preferably, the photoinitiator is 2-hydroxy-2-methylphenylacetone (1173).

[0017] For most photoinitiators, the wavelength of ultraviolet light they absorb is mainly in the range of 250nm to 400nm. During the curing stage, a 365nm UV light source (light intensity 80 mW / cm²) and a 395nm light source (light intensity 120 mW / cm²) are used to initiate surface cross-linking and deep curing to form a dense layer.

[0018] Further, the monomers mentioned above include at least one of monofunctional monomers, difunctional monomers, multifunctional monomers, and functional monomers. Preferably, the monofunctional monomers include at least one of isooctyl acrylate (IOA) and methyl methacrylate (MMA). The difunctional monomers include at least one of trimethylolpropane diacrylate (DPGDA) and ethylene glycol diacrylate (EGDA). The multifunctional monomers include at least one of trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA). The functional monomers include at least one of hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA). More preferably, the monomers include at least one of trimethylolpropane diacrylate (DPGDA) and hydroxyethyl acrylate (HEA).

[0019] In step (1), the concentration of the polyetherimide resin solution is 25~35 wt%. The solvent in the polyetherimide matrix solution is N-methylpyrrolidone (NMP).

[0020] In step (3), the proportion of polyetherimide matrix solution in UV-PEI casting solution is 90~98wt%, and the proportion of UV curing mixture is 2~5wt%.

[0021] In the UV-curable hybrid system, the content of its main components is as follows: 45-55 wt% of photosensitive prepolymer Monomer 45~55 wt%, Photoinitiator 2-5 wt%.

[0022] Furthermore, the wet film thickness coated with UV-PEI casting solution is 50-150 μm.

[0023] Another objective of this invention is to provide a low dielectric loss polyetherimide film prepared by the above-described preparation method.

[0024] Compared with the prior art, the present invention has the following advantages: (1) By designing a UV curing system, the PEI resin solution is combined with a mixture containing photoinitiator and photosensitive prepolymer. The gradient UV curing process achieves low-temperature and high-efficiency film formation. The introduction of photosensitive prepolymer crosslinking restricts molecular chain relaxation, increases the dielectric constant of the film, reduces dielectric loss, and increases the average field strength of the withstand voltage. (2) By introducing monomers to regulate the polarity of UV-curing components and combining this with solution blending, the compatibility problem between the PEI matrix and the UV components is solved, and the mechanical property degradation caused by phase separation is avoided. (3) The polyetherimide film prepared by the present invention has a dielectric constant of 4.8-5.1 (1 kHz), and reduces dielectric loss tanδ<0.004 (1 kHz), with an average withstand voltage field strength >450 MV / m; (4) The polyetherimide film prepared, after post-treatment such as gradient heating, has excellent temperature resistance (Tg remains >200℃), tensile strength >90 MPa, elastic modulus >1900MPa, and elongation at break >50%, which can meet the effect of tension roller force in roll-to-roll production. Roll-to-roll production provides feasibility for the mass production of dielectric films. (5) The process time is reduced to 1 / 3 of the traditional method, which improves production efficiency. Attached Figure Description

[0025] Figure 1 A schematic diagram of a roll-to-roll UV coating and heat gradient curing process; Figure 2 A practical diagram illustrating the first stage of UV curing in roll-to-roll production; Figure 3 A photograph of the PEI film roll prepared by the method of this invention; Figure 4 The breakdown field strength distribution at each point in the 50-point withstand voltage test of the PEI films prepared in Example 1 and Comparative Examples 1-3 is shown in the diagram. Figure 5 The DSC test curves for Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] To address at least some of the technical problems in the prior art, the present invention provides a method for preparing PEI capacitor film.

[0028] A method for preparing a UV-type PEI dielectric thin film, characterized by comprising the following steps: (1) Preparation of PEI matrix solution: dissolve polyetherimide resin in a polar solvent to form a matrix solution; (2) Preparation of UV functionalized mixture: Photosensitive prepolymer such as acrylate prepolymer, monomer and photoinitiator are mixed and degassed; wherein the monomer is preferably a bifunctional monomer and a functional monomer to increase its polarity, thereby enhancing the hydrogen bonding with PEI (-OH forms hydrogen bonds with C=O of PEI), enhancing the compatibility of the two-component system of casting solution, that is, regulating the polarity of UV component.

[0029] (3) Preparation of two-component UV-PEI casting solution: PEI matrix solution and UV functionalized mixture are mixed at a certain mass ratio and at a certain temperature; (4) Coating casting solution to form a film and pre-drying it, then performing gradient UV curing under nitrogen protection and drying it at gradient temperature in a tunnel oven; (5) Post-processing yields a PEI film with high dielectric constant, low loss and flexibility.

[0030] In step (3), the UV-PEI casting solution is prepared by adding a UV functionalized mixture at a rate of 2 to 5 wt% of the total mass of the UV-PEI casting solution.

[0031] In step (4), the gradient UV curing includes: Phase 1: 365 nm wavelength, light intensity 50-100 mW / cm², irradiation time 10-60 s; Second stage: 395 nm wavelength, light intensity 100-150 mW / cm², synchronous heating to 60~100℃, irradiation time 30~120 s.

[0032] Specifically, the present invention includes the following.

[0033] The present invention provides a method for preparing a PEI capacitor film, which includes the following steps: Step 1: Raw material preparation PEI matrix solution preparation: Dissolve polyetherimide resin (Ultem® 1000) in N-methylpyrrolidone (NMP) (concentration 25~35 wt%) and stir at 60~80°C until completely dissolved.

[0034] Preparation of UV-functionalized mixed liquid: 45-55 wt% of photosensitive prepolymer, 45-55 wt% of monomer, and 2-5 wt% of photoinitiator are dissolved in N,N-dimethylformamide (DMF) and stirred at 35-45°C until completely dissolved.

[0035] The photosensitive prepolymer is one or more of the following: polyurethane acrylate (PUA) prepolymer, such as polycaprolactone polyurethane acrylate; polyester acrylate (PEA) prepolymer, such as polyethylene terephthalate acrylate; epoxy acrylate (EA) prepolymer, such as bisphenol A epoxy acrylate; silicone-modified acrylate (siloxane PUA) prepolymer, such as silyl-terminated polyurethane acrylate; preferably polycaprolactone polyurethane acrylate.

[0036] The monomers are monofunctional monomers, such as isooctyl acrylate (IOA) and methyl methacrylate (MMA); difunctional monomers, such as trimethylolpropane diacrylate (DPGDA) and ethylene glycol diacrylate (EGDA); polyfunctional monomers, such as trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA); and functional monomers, such as one or more of hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA), preferably the difunctional monomer trimethylolpropane diacrylate (DPGDA) and the functional monomer hydroxyethyl acrylate (HEA), to increase their polarity and enhance their hydrogen bonding with PEI (-OH forms hydrogen bonds with the C=O of PEI), thereby regulating the polarity of the UV components.

[0037] The photoinitiator is one or more of 2-hydroxy-2-methylphenylacetone (1173), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), and 3-coumarinone derivative (LFC3260), preferably 2-hydroxy-2-methylphenylacetone (1173).

[0038] For most photoinitiators, the wavelength of ultraviolet light they absorb is mainly in the range of 250nm to 400nm. During the curing stage, a 365nm UV light source (light intensity 80 mW / cm²) and a 395nm light source (light intensity 120 mW / cm²) are used to initiate surface cross-linking and deep curing to form a dense layer.

[0039] Step 2: Preparation of UV-PEI casting solution and coating for film formation 90-98 wt% (PEI matrix solution) and 2-5 wt% (based on UV-PEI casting solution) UV functionalized mixture were mixed in a certain proportion, ultrasonically stirred at 30-40℃ for 20-40 min, and then vacuum degassed to obtain a two-component UV-PEI casting solution.

[0040] On the roll-to-roll coating line, UV-PEI casting liquid is pumped into the doctor blade trough through the pumping system, and coated onto the PET film using the slot coating method. The wet film thickness is 50-150 μm, and the base film speed is 2-10 m / min.

[0041] Step 3: Gradient UV + Heat Curing First stage: Under a nitrogen atmosphere, irradiate with a 365 nm UV light source (light intensity 80 mW / cm²) for 10~60 s to induce surface cross-linking and form a dense layer.

[0042] Second stage: Enter the tunnel oven, switch to a 395 nm light source (120 mW / cm²), and simultaneously heat to 60~100℃, continuously irradiating for 30~120 s to promote deep curing. Pre-dry at a gradient temperature of 60~100℃ in the tunnel oven for 3~8 min to remove some of the solvent.

[0043] Step 4: Post-processing The cured PEI film is peeled off from the PEI base film, and then heat-treated at temperatures of 160~200℃ and 120~250℃ respectively to remove residual solvent and stretched appropriately with a stretching ratio of 1.5~1.9.

[0044] The strategy of this invention is to introduce UV curing technology into PEI film formation, thereby hindering the movement of local segments in the PEI polymer molecular chain and further forming a cross-linked network structure in the PEI system to restrict molecular chain relaxation.

[0045] By designing a UV-curable composite system that combines PEI resin with functionalized acrylate prepolymers, low-temperature, high-efficiency film formation and dielectric property control are achieved. Continuous film production is realized through a roll-to-roll coating UV + heat gradient curing process.

[0046] Example 1

[0047] 1. Preparation of PEI matrix solution: Dissolve polyetherimide resin (Ultem® 1000) in N-methylpyrrolidone (NMP) at a concentration of 30 wt%, and stir at 80°C until completely dissolved.

[0048] 2. Preparation of UV functionalized mixture: 55 wt% caprolactone polyurethane acrylate photosensitive prepolymer, 30 wt% trimethylolpropane diacrylate (DPGDA) monomer, 15 wt% hydroxyethyl acrylate (HEA) monomer, and 3 wt% 2-hydroxy-2-methylphenylacetone (1173) photoinitiator were added to N,N-dimethylformamide (DMF) and stirred at 35 °C until completely dissolved.

[0049] 3. Preparation of two-component UV-PEI casting solution: Based on PEI matrix solution, 97 wt% PEI matrix solution and 3 wt% UV functionalized mixture were mixed in proportion; after ultrasonic stirring at 40℃ for 40 min, vacuum degassing was performed to obtain two-component UV-PEI casting solution.

[0050] 4. On the roll-to-roll coating line, the UV-PEI casting liquid is pumped into the doctor blade trough through the pumping system, and the film is coated on the PET film using the slit coating method. The wet film thickness is 120 μm, and the base film speed is 8m / min.

[0051] 5. After coating, the wet film is irradiated with a 365 nm UV light source (light intensity 80 mW / cm²) for 30 s in a nitrogen atmosphere to induce surface cross-linking and form a dense layer.

[0052] 6. The film is placed in a tunnel oven and switched to a 395 nm light source (120 mW / cm²), simultaneously heated to 80°C, and continuously irradiated for 60 seconds to promote deep curing. Pre-drying is then performed in the tunnel oven at a gradient temperature of 60–100°C for 8 minutes to remove some of the solvent. The film is then wound up to obtain the cured PEI film. A schematic diagram of the roll-to-roll coating UV heating gradient curing process is shown below. Figure 1 As shown in the diagram, 1 represents unwinding, 2 represents coating, 3 represents UV curing, 4 represents the oven, and 5 represents rewinding. The practical diagram of the first stage of roll-to-roll production using UV curing is shown below. Figure 2 As shown.

[0053] 7. Peel the cured PEI film from the PEI base film, then heat-treat at 180°C and 230°C respectively to remove residual solvent, and stretch it moderately at a stretch ratio of 1.8. A picture of the actual PEI film roll is shown below. Figure 3 As shown.

[0054] Comparative Example 1 1. Preparation of single-component PEI casting solution: 100 wt% PEI matrix solution is used as the casting solution.

[0055] 2. Film formation process: Same as in Example 1.

[0056] Comparative Example 2 1. Preparation of two-component UV-PEI casting solution: Based on the PEI matrix solution, 98.5 wt% PEI matrix solution and 1.5 wt% UV functionalized mixture are mixed in proportion.

[0057] 2. Film formation process: Same as in Example 1.

[0058] Comparative Example 3 1. Preparation of two-component UV-PEI casting solution: Based on PEI matrix solution, 92 wt% PEI matrix solution and 8 wt% UV functionalized mixture are mixed in proportion.

[0059] 2. Film formation process: Same as in Example 1.

[0060] Performance testing The dielectric constant, dielectric loss, and mechanical properties of the polyetherimide films prepared in Example 1 and Comparative Examples 1-3 were tested.

[0061] The dielectric constant and dielectric loss of the thin film were measured and calculated using an E4990A impedance analyzer, and the tests were performed in accordance with IEC60250:2017.

[0062] The film was subjected to a 50-point withstand voltage test using a CDI-20 withstand voltage strength tester, in accordance with GB / T13542.2-2009.

[0063] The tensile strength, elastic modulus, and elongation at break of the film were tested using a CMT6103 electronic universal testing machine, in accordance with GB / T 1040.3-2006.

[0064] 1. The DSC test curves of Example 1 and Comparative Example 1 are shown below. Figure 5 As shown in the table below, the glass transition temperature, dielectric constant, and dielectric loss performance parameters of the PEI films prepared in Examples 1 and Comparative Examples 1-3 are as follows.

[0065]

[0066] As can be seen from the data in the table, compared with the comparative example, the glass transition temperature of Example 1 decreased, but remained above 200°C, the dielectric constant was significantly improved, and the dielectric loss was significantly reduced.

[0067] 2. Example 1: Voltage withstand performance test of PEI films prepared in Comparative Examples 1-3 at 50 points. The breakdown field strength distribution at each point is shown in the figure. Figure 4 As shown in the table below, the 50-point withstand voltage performance test results of the PEI films prepared in Examples 1 and Comparative Examples 1-3 are as follows.

[0068]

[0069] By comparing Example 1, Comparative Example 2 and Comparative Example 1, it can be seen that adding UV functionalized mixture to the pure PEI system can effectively improve the breakdown resistance of the film. The possible reason is that the addition of UV functionalized mixture system, after UV curing, will hinder the movement of local chain segments in the PEI polymer molecular chain in the original PEI structure, and further form a cross-linked network structure in the PEI system to restrict molecular chain relaxation, thereby improving the overall dielectric properties.

[0070] By comparing Examples 1, 2, and 3, it can be seen that as the total content of the UV-functionalized mixture system in the UV-PEI casting solution increases, its breakdown resistance first increases and then decreases. This may be because, firstly, as the content of the UV-functionalized mixture increases, the cross-linking system in the cured PEI film increases, which enhances the restraint effect on the movement of local chain segments in the PEI polymer molecular chain, thus increasing the breakdown resistance of the system. Subsequently, further increasing the content of the UV-functionalized mixture increases the content of UV resin (such as acrylate PUA) in the PEI system, leading to a decrease in the overall dielectric properties of the film.

[0071] 3. The mechanical properties of the PEI films prepared in Examples 1 and Comparative Examples 1-3 are shown in the table below.

[0072]

[0073] A comparison of the mechanical property data of Example 1 and Comparative Examples 1-3 in the table shows that, compared with pure PEI film, the mechanical properties of the two-component PEI film with added UV functionalized mixed liquid system are slightly reduced. The mechanical properties decrease with increasing content. When a small amount is added, the two-component PEI film can still maintain a certain mechanical strength due to the inter-chain entanglement during the UV curing crosslinking process. When the content is further increased, the mechanical properties of the film decrease significantly due to the high flexibility of the acrylic resin molecular chain. In the test, when the two components are kept in the ratio in Example 1, they can still maintain a certain mechanical property, which can meet the requirements of the tension roller force in roll-to-roll production, providing feasibility for mass production of film.

[0074] In summary, the PEI film prepared by the method of this invention exhibits a dielectric constant ε of 4.8-5.1 (1 kHz), dielectric loss tanδ < 0.004, average withstand voltage field strength > 450 MV / m, excellent temperature resistance (Tg remains > 200℃), tensile strength > 90 MPa, elastic modulus > 1900 MPa, and elongation at break > 50%, which can meet the requirements of tension rollers in roll-to-roll production. The roll-to-roll coating UV + heating gradient curing process provides feasibility for the industrial mass production of dielectric films, reducing the process time to 1 / 3 of traditional methods and enabling continuous film production.

[0075] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention and should be defined by the claims.

Claims

1. A method for preparing a low dielectric loss polyetherimide film, characterized in that, Includes the following steps, (1) Dissolve polyetherimide in a solvent to obtain a polyetherimide matrix solution; (2) The photosensitive prepolymer and the photoinitiator are mixed to obtain a UV-curable hybrid system; (3) The polyetherimide matrix solution is blended with the UV curing mixture to obtain the UV-PEI casting solution, and the UV-PEI casting solution is coated to form a film; (4) The membrane obtained in step (3) is subjected to gradient ultraviolet light curing to obtain a polyetherimide membrane with low dielectric loss.

2. The preparation method according to claim 1, characterized in that, In step (2), the UV-curable hybrid system also includes monomers, and the functional groups in the monomers include at least one of carbon-carbon double bonds and hydroxyl groups.

3. The preparation method according to claim 1 or 2, characterized in that, In step (4), gradient ultraviolet curing includes the following steps: The first stage involves irradiating the film surface with a UV light source of 300-375 nm and an intensity of 50-100 mW / cm² for 10-60 seconds to induce cross-linking. The second stage involves irradiating the interior with a 375-395 nm ultraviolet light source with an intensity of 100-150 mW / cm² at 60-100℃ for 30-120 seconds to achieve deep curing.

4. The preparation method according to claim 3, characterized in that, In step (4), the cured polyetherimide (PEI) film undergoes post-treatment, which includes pre-drying at a gradient temperature of 60-100 °C for 3-8 min to remove some of the solvent.

5. The preparation method according to claim 4, characterized in that, The post-processing steps also include heat-treating the pre-dried PEI film at temperatures of 160~200℃ and 120~250℃ respectively to remove residual solvents and stretching it appropriately with a stretching ratio of 1.5~1.

9.

6. The preparation method according to claim 1 or 2, characterized in that, The photosensitive prepolymer includes at least one of polyurethane acrylate prepolymer, polyester acrylate prepolymer, epoxy acrylate prepolymer, and silicone-modified acrylate prepolymer.

7. The preparation method according to claim 1 or 2, characterized in that, The photoinitiator includes at least one of 2-hydroxy-2-methylphenylacetone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 3-coumarinone derivatives.

8. The preparation method according to claim 2, characterized in that, The monomers include at least one of isooctyl acrylate, methyl methacrylate, trimethylolpropane diacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, hydroxyethyl acrylate, and glycidyl methacrylate.

9. The preparation method according to claim 2, characterized in that, In step (1), the concentration of the polyetherimide solution is 25-35 wt%. In step (3), the proportion of the polyetherimide matrix solution in the UV-PEI casting solution is 90-98 wt%, and the proportion of the UV curing mixture is 2-5 wt%. In the UV-curable hybrid system, the content of its main components is as follows: 45-55 wt% of photosensitive prepolymer Monomer 45~55 wt%, Photoinitiator 2-5 wt%.

10. A low dielectric loss polyetherimide film prepared by the preparation method according to claim 1 or 2.

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