A photosensitive resin composition and a method for preparing the same

Abstract

The application discloses a photosensitive resin composition and a preparation method thereof, and particularly relates to the technical field of electronic chemicals. In view of the fact that traditional photosensitive resin is difficult to balance the bending performance and heat resistance, the composition is composed of photosensitive resin, photoinitiator, filler, flame retardant and additive. The core lies in that rigid-flexible synergistic design is performed on polyimide and polyurethane acrylate, and the interface adhesion is enhanced in combination with epoxy resin. In the preparation, a process flow of high-temperature dissolution, medium-temperature mixing, fineness control and segmented curing is adopted. The test shows that the adhesion of the prepared resin composition reaches 5B level, the flame retardant level is V-0, the heat distortion temperature is as high as 185 DEG C, and the bending resistance times are more than 10,000 times. The application realizes synchronous improvement of mechanical flexibility and heat stability without sacrificing photosensitivity, has obvious progressiveness, and is particularly suitable for the fields of flexible electronics and high-end packaging.

Description

Technical Field

[0001] This invention relates to the field of electronic chemicals technology, and to a photosensitive resin composition and its preparation method. Background Technology

[0002] In the manufacturing process of printed circuit boards and flexible electronic devices, photosensitive resin compositions, as a key photosensitive material, are widely used in core processes such as pattern transfer, solder mask protection, and encapsulation. Existing photosensitive resin technologies typically use polyvinyl alcohol as the film-forming resin, combined with linear phenolic resin as a sensitizer, and supplemented with diazonaphthoquinone photoinitiators to form the basic formulation system. This traditional system has long dominated the electronic chemicals market due to its mature technology, low cost, and acceptable photosensitivity.

[0003] However, with the rapid development of electronic devices towards thinner, lighter, more flexible, and higher-frequency, high-speed operation, the limitations of traditional photosensitive resin systems in terms of performance are becoming increasingly apparent. Existing resin compositions often struggle to balance mechanical properties and thermal stability. Specifically, in terms of heat resistance, traditional phenolic resin systems have low heat distortion temperatures, making them prone to softening and deformation during high-temperature pressing or welding, leading to protective layer failure. Regarding bending performance, their molecular structure is highly rigid and lacks flexibility, making them highly susceptible to cracking or even breakage when subjected to repeated bending or dynamic stress, failing to meet the stringent requirements for bending lifespan in flexible circuit boards and foldable display devices.

[0004] Furthermore, this "one-sided" performance defect severely restricts the application of photosensitive resins in high-end electronics. Increasing rigid components to improve heat resistance often leads to material brittleness and further deterioration of bending performance; conversely, introducing flexible segments to improve flexibility may result in a decrease in glass transition temperature, making it difficult to meet heat resistance standards. Therefore, overcoming these shortcomings of existing technologies and developing a novel photosensitive resin composition that can maintain good photosensitivity while simultaneously improving mechanical flexibility and thermal stability has become a pressing technical challenge for those skilled in the art. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a photosensitive resin composition and its preparation method, which solves the problem of poor bending and heat resistance of photosensitive resin.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A photosensitive resin composition comprises 40-70 parts by weight of photosensitive resin, 1-5 parts by weight of photoinitiator, 10-30 parts by weight of filler, 5-15 parts by weight of flame retardant, 2-10 parts by weight of organic filler, 1-8 parts by weight of pigment, 0.5-3 parts by weight of curing accelerator, 0.2-1.5 parts by weight of defoamer, 0.1-1 parts by weight of leveling agent, 0.1-1 parts by weight of lubricant, and 5-15 parts by weight of polar solvent.

[0007] Preferably, the photosensitive resin is composed of 15-25 parts by weight of polyimide, 10-20 parts by weight of polyurethane acrylate, 10-20 parts by weight of bisphenol A type liquid epoxy resin, and 5-15 parts by weight of acrylate monomer; the photoinitiator is 1-hydroxycyclohexylphenyl ketone; and the filler is silica.

[0008] Preferably, the flame retardant is decabromodiphenyl ethane; and the organic filler is polytetrafluoroethylene micro powder.

[0009] Preferably, the colorant is titanium dioxide; the curing accelerator is 2-methylimidazole; the defoamer is tributyl phosphate; the leveling agent is polyether-modified polydimethylsiloxane; the lubricant is polyether-modified polysiloxane; and the polar solvent is N-methylpyrrolidone.

[0010] Preferably, the bisphenol A type liquid epoxy resin has an epoxy value of 0.48~0.54 eq / 100g, an epoxy equivalent of 185~208g / eq, a viscosity of 11000~15000mPa·s at 25℃, and a hydrolyzed chlorine content ≤0.1%; the polyimide is a soluble polyimide containing ether bonds, sulfone groups, or flexible segments.

[0011] A method for preparing a photosensitive resin composition includes the following steps: S1: Add polyimide, epoxy resin and polar solvent to the reactor, then raise the temperature of the reactor and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C, and add polyurethane acrylate and acrylate monomer and stir thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, and then continuously and uniformly disperse the mixture to obtain a mixture B in which the solid powder is completely wetted. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind the mixture using a sand mill to obtain a slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine for processing to obtain a photosensitive resin composition.

[0012] Preferably, the temperature of the reactor is raised to 120~150°C as described in S1.

[0013] Preferably, after adding photoinitiator, curing accelerator, flame retardant and colorant to S2, the mixture is stirred continuously at a speed of 1000~1500 rpm for 30~60 minutes.

[0014] Preferably, in S3, a sand mill is used to grind the mixture to a fineness of ≤15μm.

[0015] Preferably, in step S4, the slurry is placed in a vacuum degassing machine at -0.10 to -0.05 MPa for 1 to 2 hours.

[0016] The technical effects and advantages of the photosensitive resin composition and its preparation method of the present invention are as follows: 1. This invention, through the rigid-flexible synergistic design of polyimide and polyurethane acrylate, combined with epoxy resin to enhance interfacial adhesion, effectively solves the technical contradictions of traditional photosensitive resins in terms of bending performance and heat resistance.

[0017] 2. The invention employs a process of high-temperature dissolution, medium-temperature mixing, fineness control, and segmented curing in its preparation process. Compared with existing technologies, it achieves simultaneous improvement in mechanical flexibility and thermal stability without sacrificing photosensitivity and flame retardant properties.

[0018] 3. The resin composition prepared by this invention has excellent comprehensive properties and is especially suitable for high-end application scenarios such as flexible circuit boards and foldable display devices.

[0019] 4. This invention, through molecular structure design and process optimization, avoids the functional limitations of using traditional phenolic resin systems, and has significant progressiveness and practicality.

[0020] 5. This invention uses photo-initiated free radical polymerization of acrylate monomers to form a first cross-linked network; subsequently, under heating conditions, imidazole accelerators catalyze the ring-opening polymerization of epoxy resin to form a second cross-linked network. The two networks interpenetrate to form an interpenetrating polymer network structure, which not only ensures the rapid photoresponse required for photolithographic patterning, but also improves the overall cross-linking density and thermodynamic properties through the post-curing of epoxy resin. Attached Figure Description

[0021] Figure 1 This invention relates to a photosensitive resin composition and its preparation method. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] 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 entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, 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 limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] Example 1

[0025] This embodiment provides a photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Photosensitive resin: 20 parts by weight of polyimide, 15 parts by weight of polyurethane acrylate, 15 parts by weight of bisphenol A type liquid epoxy resin, and 5 parts by weight of acrylate monomer; Photoinitiator: 3 parts by weight of 1-hydroxycyclohexylphenyl ketone; Filler: 20 parts by weight of silica; Flame retardant: 10 parts by weight of decabromodiphenyl ethane; Organic filler: 5 parts by weight of polytetrafluoroethylene micro powder; Pigment: 4 parts by weight of titanium dioxide; Curing accelerator: 1.5 parts by weight of 2-methylimidazole; Defoamer: 0.8 parts by weight of tributyl phosphate; Leveling agent: 0.5 parts by weight of polyether-modified polydimethylsiloxane; Lubricant: 0.5 parts by weight of polyether-modified polysiloxane; Polar solvent: 15 parts by weight of N-methylpyrrolidone.

[0026] Experimental objective: A photosensitive resin composition was prepared.

[0027] Experimental steps: S1: Add polyimide, epoxy resin, and N-methylpyrrolidone to the reactor, then raise the temperature of the reactor to 120°C and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C and add polyurethane acrylate and acrylate monomer, and stir thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, then continuously disperse the mixture at 1000 rpm for 60 minutes, and finally ensure that the solid powder is completely wetted to obtain mixture B. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind it with a sand mill until the fineness of the mixture is ≤15μm to obtain slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine at -0.08MPa for 1 hour to obtain a photosensitive resin composition; S5: The photosensitive resin composition obtained in S4 is coated onto the substrate by screen printing, and then the substrate is placed in an oven at 90°C and baked for 10 minutes to obtain a preliminary set resin. S6: Place the resin that has been preliminarily shaped in S5 at 365nm and 800mJ / cm. 2 Expose in an exposure machine for 1 hour, and after exposure, develop in a 1wt% K2CO3 solution at 30℃; S7: After development, the resin was placed in an oven at 150°C and dried for 60 minutes. Finally, the resin was cooled to room temperature and its adhesion, flame retardancy and photosensitivity were tested.

[0028] Experimental results: See Table 1 for details.

[0029] Table 1: Test Results of Example 1 Test Project result Adhesion 5B Flame retardant rating V-0 Light sensitivity (exposure energy) <![CDATA[350mJ / cm 2 ]]> Bending performance (number of 180° bends) ≥10,000 cycles without cracking Thermal decomposition temperature (Td, 5% weight loss) 312℃ Heat distortion temperature (HDT) 185℃ Example 1 utilizes a rigid-flexible synergistic design of polyimide and polyurethane acrylate, combined with epoxy resin to enhance interfacial adhesion. The preparation process employs high-temperature dissolution, medium-temperature mixing, fineness control, and segmented curing, effectively resolving the technical contradiction between bending performance and heat resistance in traditional photosensitive resins. Compared to existing technologies, this example achieves simultaneous improvement in mechanical flexibility and thermal stability without sacrificing photosensitivity and flame retardant properties, making it particularly suitable for high-end applications such as flexible circuit boards and foldable display devices.

[0030] Example 2

[0031] This embodiment provides a photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Photosensitive resin: 10 parts by weight of polyimide, 15 parts by weight of polyurethane acrylate, 15 parts by weight of bisphenol A type liquid epoxy resin, and 5 parts by weight of acrylate monomer; Photoinitiator: 3 parts by weight of 1-hydroxycyclohexylphenyl ketone; Filler: 20 parts by weight of silica; Flame retardant: 10 parts by weight of decabromodiphenyl ethane; Organic filler: 5 parts by weight of polytetrafluoroethylene micro powder; Pigment: 4 parts by weight of titanium dioxide; Curing accelerator: 1.5 parts by weight of 2-methylimidazole; Defoamer: 0.8 parts by weight of tributyl phosphate; Leveling agent: 0.5 parts by weight of polyether-modified polydimethylsiloxane; Lubricant: 0.5 parts by weight of polyether-modified polysiloxane; Polar solvent: 15 parts by weight of N-methylpyrrolidone.

[0032] Experimental objective: By changing the ratio of raw materials, the effects of different raw material ratios on the properties of photosensitive resin were investigated.

[0033] Experimental steps: S1: Add polyimide, epoxy resin, and N-methylpyrrolidone to the reactor, then raise the temperature of the reactor to 120°C and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C and add polyurethane acrylate and acrylate monomer, and stir thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, then continuously disperse the mixture at 1000 rpm for 60 minutes, and finally ensure that the solid powder is completely wetted to obtain mixture B. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind it with a sand mill until the fineness of the mixture is ≤15μm to obtain slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine at -0.08MPa for 1 hour to obtain a photosensitive resin composition; S5: The photosensitive resin composition obtained in S4 is coated onto the substrate by screen printing, and then the substrate is placed in an oven at 90°C and baked for 10 minutes to obtain a preliminary set resin. S6: Place the resin that has been preliminarily shaped in S5 at 365nm and 800mJ / cm. 2 Expose in an exposure machine for 1 hour, and after exposure, develop in a 1wt% K2CO3 solution at 30℃; S7: After development, the resin was placed in an oven at 150°C and dried for 60 minutes. Finally, the resin was cooled to room temperature and its adhesion, flame retardancy and photosensitivity were tested.

[0034] Experimental results: See Table 2 for details.

[0035] Table 2: Test Results of Example 2 Test Project result Adhesion 3B Flame retardant rating V-0 Light sensitivity (exposure energy) <![CDATA[380mJ / cm 2 ]]> Bending performance (number of 180° bends) ≥3500 cycles without cracking Thermal decomposition temperature (Td, 5% weight loss) 268℃ Heat distortion temperature (HDT) 151℃ Compared to Example 1, Example 2 reduced the amount of polyimide used. Since polyimide is the main source of rigid segments, its molecular structure contains a large number of aromatic heterocycles, which endow the material with extremely high modulus and heat resistance. In Example 2, the reduction of PI content leads to a reduction in rigid skeleton. Although the flexibility increases slightly, the interaction force between molecular chains weakens, resulting in a decrease in glass transition temperature. As a result, the heat distortion temperature drops from 185°C to 151°C, and both heat resistance and mechanical strength show a significant decrease.

[0036] Example 3

[0037] This embodiment provides a photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Photosensitive resin: 20 parts by weight of polyimide, 8 parts by weight of polyurethane acrylate, 15 parts by weight of bisphenol A type liquid epoxy resin, 2 parts by weight of acrylate monomer; Photoinitiator: 3 parts by weight of 1-hydroxycyclohexylphenyl ketone; Filler: 20 parts by weight of silica; Flame retardant: 10 parts by weight of decabromodiphenyl ethane; Organic filler: 5 parts by weight of polytetrafluoroethylene micro powder; Defoamer: 0.8 parts by weight of tributyl phosphate; Leveling agent: 0.5 parts by weight of polyether-modified polydimethylsiloxane; Lubricant: 0.5 parts by weight of polyether-modified polysiloxane; Polar solvent: 15 parts by weight of N-methylpyrrolidone.

[0038] Experimental objective: This study investigates the impact of eliminating the use of curing accelerators and colorants on photosensitive resin compositions.

[0039] Experimental steps: S1: Add polyimide, epoxy resin, and N-methylpyrrolidone to the reactor, then raise the temperature of the reactor to 120°C and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C and add polyurethane acrylate and acrylate monomer, and stir thoroughly to obtain mixture A. S2: Add photoinitiator and flame retardant to the final mixture A obtained in S1, then continuously disperse the mixture at a speed of 1000 rpm for 60 minutes, and finally ensure that the solid powder is completely wetted to obtain mixture B. S3: Add filler, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind it with a sand mill until the fineness of the mixture is ≤15μm to obtain slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine at -0.08MPa for 1 hour to obtain a photosensitive resin composition; S5: The photosensitive resin composition obtained in S4 is coated onto the substrate by screen printing, and then the substrate is placed in an oven at 90°C and baked for 10 minutes to obtain a preliminary set resin. S6: Place the resin that has been preliminarily shaped in S5 at 365nm and 800mJ / cm. 2 Expose in an exposure machine for 1 hour, and after exposure, develop in a 1wt% K2CO3 solution at 30℃; S7: After development, the resin was placed in an oven at 150°C and dried for 60 minutes. Finally, the resin was cooled to room temperature and its adhesion, flame retardancy and photosensitivity were tested.

[0040] Experimental results: See Table 3 for details.

[0041] Table 3: Test Results of Example 3 Test Project result Adhesion 2B Flame retardant rating V-2 Light sensitivity (exposure energy) <![CDATA[620mJ / cm 2 ]]> Bending performance (number of 180° bends) No cracking after 800 cycles Thermal decomposition temperature (Td, 5% weight loss) 231℃ Heat distortion temperature (HDT) 118℃ In Example 3, the removal of curing accelerator and titanium dioxide, coupled with the absence of 2-methylimidazole's catalytic effect on the ring-opening polymerization of epoxy resin, significantly reduced the crosslinking density of the system, resulting in an incomplete three-dimensional network structure and thus greatly weakening the mechanical strength and adhesion of the resin. Simultaneously, the absence of titanium dioxide as an inorganic filler not only reduced the flame-retardant synergistic effect of the system but also decreased the physical shielding effect, making the material more susceptible to degradation in a thermo-oxidative environment, with the thermal decomposition temperature dropping to 231°C.

[0042] Example 4

[0043] This embodiment provides a photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Photosensitive resin: 20 parts by weight of polyimide, 15 parts by weight of polyurethane acrylate, 15 parts by weight of bisphenol A type liquid epoxy resin, and 5 parts by weight of acrylate monomer; Photoinitiator: 3 parts by weight of 1-hydroxycyclohexylphenyl ketone; Filler: 20 parts by weight of silica; Flame retardant: 10 parts by weight of decabromodiphenyl ethane; Organic filler: 5 parts by weight of polytetrafluoroethylene micro powder; Pigment: 4 parts by weight of titanium dioxide; Curing accelerator: 1.5 parts by weight of 2-methylimidazole; Defoamer: 0.8 parts by weight of tributyl phosphate; Leveling agent: 0.5 parts by weight of polyether-modified polydimethylsiloxane; Lubricant: 0.5 parts by weight of polyether-modified polysiloxane; Polar solvent: 15 parts by weight of N-methylpyrrolidone.

[0044] Experimental objective: To investigate the effect of increasing the temperature in the reactor in S1 on the final photosensitive resin.

[0045] Experimental steps: S1: Add polyimide, epoxy resin, and N-methylpyrrolidone to the reactor, then raise the temperature of the reactor to 150°C and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C and add polyurethane acrylate and acrylate monomer, stirring thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, then continuously disperse the mixture at 1000 rpm for 60 minutes, and finally ensure that the solid powder is completely wetted to obtain mixture B. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind it with a sand mill until the fineness of the mixture is ≤15μm to obtain slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine at -0.08MPa for 1 hour to obtain a photosensitive resin composition; S5: The photosensitive resin composition obtained in S4 is coated onto the substrate by screen printing, and then the substrate is placed in an oven at 90°C and baked for 10 minutes to obtain a preliminary set resin. S6: Place the resin that has been preliminarily shaped in S5 at 365nm and 800mJ / cm. 2 Expose in an exposure machine for 1 hour, and after exposure, develop in a 1wt% K2CO3 solution at 30℃; S7: After development, the resin was placed in an oven at 150°C and dried for 60 minutes. Finally, the resin was cooled to room temperature and its adhesion, flame retardancy and photosensitivity were tested.

[0046] Experimental results: See Table 4 for details.

[0047] Table 4: Test Results of Example 4 Test Project result Adhesion 5B Flame retardant rating V-0 Light sensitivity (exposure energy) <![CDATA[340mJ / cm 2 ]]> Bending performance (number of 180° bends) ≥10,000 cycles without cracking Thermal decomposition temperature (Td, 5% weight loss) 310℃ Heat distortion temperature (HDT) 183℃ Example 4 involves increasing the temperature in the reactor to 150°C. While the increased temperature accelerates the dissolution rate of polyimide and epoxy resin, the excessively high temperature approaches the thermal initiation threshold of some acrylate monomers, potentially leading to localized thermal polymerization reactions. This results in the formation of microgels or a broadening of the molecular weight distribution in the prepolymer during the mixing stage, which disrupts the molecular weight uniformity of the prepolymer. Although the heat resistance after final curing is similar to that of Example 1, it may affect the long-term storage stability and microstructure uniformity of the material.

[0048] Example 5

[0049] This embodiment provides a photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Photosensitive resin: 20 parts by weight of polyimide, 15 parts by weight of polyurethane acrylate, 15 parts by weight of bisphenol A type liquid epoxy resin, and 5 parts by weight of acrylate monomer; Photoinitiator: 3 parts by weight of 1-hydroxycyclohexylphenyl ketone; Filler: 20 parts by weight of silica; Flame retardant: 10 parts by weight of decabromodiphenyl ethane; Organic filler: 5 parts by weight of polytetrafluoroethylene micro powder; Pigment: 4 parts by weight of titanium dioxide; Curing accelerator: 1.5 parts by weight of 2-methylimidazole; Defoamer: 0.8 parts by weight of tributyl phosphate; Leveling agent: 0.5 parts by weight of polyether-modified polydimethylsiloxane; Lubricant: 0.5 parts by weight of polyether-modified polysiloxane; Polar solvent: 15 parts by weight of N-methylpyrrolidone.

[0050] Experimental objective: To investigate the effect of reducing exposure power on the final resin.

[0051] Experimental steps: S1: Add polyimide, epoxy resin, and N-methylpyrrolidone to the reactor, then raise the temperature of the reactor to 120°C and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C and add polyurethane acrylate and acrylate monomer, and stir thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, then continuously disperse the mixture at 1000 rpm for 60 minutes, and finally ensure that the solid powder is completely wetted to obtain mixture B. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind it with a sand mill until the fineness of the mixture is ≤15μm to obtain slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine at -0.08MPa for 1 hour to obtain a photosensitive resin composition; S5: The photosensitive resin composition obtained in S4 is coated onto the substrate by screen printing, and then the substrate is placed in an oven at 90°C and baked for 10 minutes to obtain a preliminary set resin. S6: Place the resin that has been preliminarily shaped in S5 at 365nm and 200mJ / cm. 2 Expose in an exposure machine for 1 hour, and after exposure, develop in a 1wt% K2CO3 solution at 30℃; S7: After development, the resin was placed in an oven at 150°C and dried for 60 minutes. Finally, the resin was cooled to room temperature and its adhesion, flame retardancy and photosensitivity were tested.

[0052] Experimental results: See Table 5 for details.

[0053] Table 5: Test Results of Example 5 Test Project result Adhesion 1B Flame retardant rating V-1 Light sensitivity (exposure energy) <![CDATA[350mJ / cm 2 ]]> Bending performance (number of 180° bends) No cracking after ≥200 cycles Thermal decomposition temperature (Td, 5% weight loss) 195℃ Heat distortion temperature (HDT) 96℃ In Example 5, the reduction in exposure power significantly affected the photocuring and crosslinking reaction of the resin. Because the exposure energy was lower than the threshold required for effective photopolymerization of the system, the concentration of free radicals generated by the photoinitiator was too low, resulting in insufficient conversion of acrylate double bonds. This made the crosslinking network structure of the cured film loose, leaving a large number of unreacted monomers and linear polymers, which led to a sharp drop in the glass transition temperature of the material, a collapse in mechanical properties, and a significant reduction in the number of bends.

[0054] This embodiment provides a conventional photosensitive resin composition and its preparation method, the specific implementation steps of which include: Experimental materials: Resin: 20-40 parts by weight of polyvinyl alcohol resin, 40-60 parts by weight of linear phenolic resin; Crosslinking agent: 5-15 parts by weight of hydroxymethylacrylamide; Photoinitiator: 1-5 parts by weight of α-hydroxymethyl benzoyl ether; Polymerization inhibitor: 0.5-2 parts by weight of hydroquinone or p-methylphenol; Solvent: 50-70 parts by weight of aqueous ethanol solution; Photoinitiator: 5-15 parts by weight of diazonoquinone type; Solvent: 50-80 parts by weight of propylene glycol methyl ether acetate.

[0055] Experimental objective: A conventional photosensitive resin composition was prepared.

[0056] Experimental steps: S1: Add polyvinyl alcohol to the solvent and stir in a water bath at 30~50℃ until completely dissolved to form a transparent solution. Then add linear phenolic resin to the solvent and stir at 40~60℃ until completely dissolved to obtain a clear resin solution. S2: Slowly add the crosslinking agent to the dissolved polyvinyl alcohol solution and continue stirring until completely dissolved; then add the photoinitiator and stir evenly, and slowly add the diazononaphthoquinone type photoinitiator to the resin solution and continue stirring to ensure full dispersion; S3: Add the polymerization inhibitor and stir at low speed for 10-15 minutes to ensure that all components are mixed evenly. Add the polyphenol compound and auxiliaries, and continue stirring at 50-60℃ for 2-4 hours to ensure that the system is stable and free of precipitation. S4: Filter both system solutions through 0.2~0.5μm filter membranes to remove insoluble impurities. Transfer the filtrate to a light-proof container, seal and store for later use. Finally, record the preparation parameters and conduct subsequent performance tests.

[0057] Experimental results: See Table 6 for details.

[0058] Table 6: Test Results of Comparative Example 1 Test Project result Adhesion 2B Flame retardant rating V-1 Light sensitivity (exposure energy) <![CDATA[400mJ / cm 2 ]]> Bending performance (number of 180° bends) No cracking after ≥600 cycles Thermal decomposition temperature (Td, 5% weight loss) 240℃ Heat distortion temperature (HDT) 120℃ refer to Figure 1 By comparing the embodiments and comparative examples, Example 1 achieves the optimal balance in mechanical strength, heat resistance, and photosensitivity. Its ingenious molecular design, combining rigidity and flexibility, enhances overall performance, making it suitable for high-end flexible electronic packaging. Example 2, while potentially reducing cost, sacrifices crucial heat resistance. Example 3 uses a filler-free and catalyst-free system, but fails to form a dense cross-linked network. Example 4 employs a high-temperature process, but carries the risk of prepolymerization. Example 5 uses low-energy exposure, but curing is incomplete. The comparative examples highlight the functional limitations of traditional phenolic resin systems. Therefore, the formulation system proposed in this invention demonstrates significant advancement and practicality.

[0059] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0060] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photosensitive resin composition, characterized by comprising: It is composed of 40-70 parts by weight of photosensitive resin, 1-5 parts by weight of photoinitiator, 10-30 parts by weight of filler, 5-15 parts by weight of flame retardant, 2-10 parts by weight of organic filler, 1-8 parts by weight of colorant, 0.5-3 parts by weight of curing accelerator, 0.2-1.5 parts by weight of defoamer, 0.1-1 parts by weight of leveling agent, 0.1-1 parts by weight of lubricant, and 5-15 parts by weight of polar solvent.

2. The photosensitive resin composition according to claim 1, wherein The photosensitive resin is composed of 15-25 parts by weight of polyimide, 10-20 parts by weight of polyurethane acrylate, 10-20 parts by weight of bisphenol A type liquid epoxy resin, and 5-15 parts by weight of acrylate monomer; the photoinitiator is 1-hydroxycyclohexylphenyl ketone; and the filler is silica.

3. The photosensitive resin composition according to claim 1, characterized in that, The flame retardant is decabromodiphenyl ethane; the organic filler is polytetrafluoroethylene micro powder.

4. The photosensitive resin composition according to claim 1, characterized in that, The colorant is titanium dioxide; the curing accelerator is 2-methylimidazole; the defoamer is tributyl phosphate; the leveling agent is polyether-modified polydimethylsiloxane; the lubricant is polyether-modified polysiloxane; and the polar solvent is N-methylpyrrolidone.

5. The photosensitive resin composition according to claim 2, characterized in that, The bisphenol A type liquid epoxy resin has an epoxy value of 0.48~0.54 eq / 100g, an epoxy equivalent of 185~208 g / eq, a viscosity of 11000~15000 mPa·s at 25℃, and a hydrolyzed chlorine content ≤0.1%; the polyimide is a soluble polyimide containing ether bonds, sulfone groups, or flexible segments.

6. A method for preparing a photosensitive resin composition, characterized in that, Includes the following steps: S1: Add polyimide, epoxy resin and polar solvent to the reactor, then raise the temperature of the reactor and stir thoroughly until completely dissolved into a homogeneous solution. Then lower the temperature of the reactor system to 80°C, and add polyurethane acrylate and acrylate monomer and stir thoroughly to obtain mixture A. S2: Add photoinitiator, flame retardant and colorant to the final mixture A obtained in S1, and then continuously and uniformly disperse the mixture to obtain a mixture B in which the solid powder is completely wetted. S3: Add filler, curing accelerator, organic filler, lubricant, defoamer and leveling agent to the final mixture B obtained in S2, and then grind the mixture using a sand mill to obtain a slurry; S4: The slurry obtained in S3 is placed in a vacuum degassing machine for processing to obtain a photosensitive resin composition.

7. The method for preparing a photosensitive resin composition as described in claim 6, characterized in that, The temperature of the reactor is raised to 120-150°C as described in S1.

8. The method for preparing a photosensitive resin composition as described in claim 6, characterized in that, After adding photoinitiator, curing accelerator, flame retardant and colorant to S2, stir continuously at 1000~1500 rpm for 30~60 minutes.

9. The method for preparing a photosensitive resin composition as described in claim 6, characterized in that, In S3, the mixture is ground using a sand mill to a fineness of ≤15μm.

10. The method for preparing a photosensitive resin composition as described in claim 6, characterized in that, In S4, the slurry is placed in a vacuum degassing machine at -0.10~-0.05MPa for 1~2 hours.

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