Photocurable resin composition and photosensitive film

Abstract

The present invention provides a photocurable resin composition and a photosensitive film. The photocurable resin composition comprises, by weight parts: 30-70 parts of an alkali-soluble resin, 10-50 parts of a polymerizable monomer, 0.5-10 parts of a photoinitiator, and 0.01-10 parts of an additive; the additive comprises a compound represented by formula (I) containing a sulfur element, R1 and R2 are each independently selected from C1-C 12 alkyl or C1-C 12 alkoxy; the sulfur element content is 100-1000 ppm per gram of the total weight of the photocurable resin composition. The compound represented by formula (I) having the above specific structure has excellent photosensitivity at 355 nm-405 nm, thereby being able to improve photosensitivity. Compared with other ranges, limiting the sulfur element content in the above range is advantageous for balancing photosensitivity, resolution performance, and adhesion performance. The compound represented by formula (I) having the above substituent is also advantageous for reducing deposits in the developing process.

Description

Technical Field

[0001] This invention relates to the field of photocurable resin technology, and more specifically, to a photocurable resin composition and a photosensitive film. Background Technology

[0002] In printed circuit boards (PCBs), lead frames, solar cells, conductor packages, BGA (Ball Grid Array) and CPS (Chip Size Package) packages, photocurable resin compositions are widely used as key materials for pattern transfer. For example, in PCB manufacturing, a photosensitive dry film resist laminate is first laminated onto a copper substrate. A mask with a specific pattern is then applied to the photocurable resin composition for pattern exposure. With technological advancements, laser direct imaging (LDI) is increasingly used in the exposure process, eliminating the need for a mask. Then, a weakly alkaline aqueous solution is used as a developer to remove unexposed areas, followed by etching or electroplating to form the pattern. Finally, a strong alkaline aqueous solution is used as a stripper to remove the cured portions, thus achieving pattern transfer.

[0003] According to the lamp source, exposure machines can be classified into UV exposure machines, LED exposure machines, and LDI exposure machines, as shown in Table 1. UV exposure machines use high-pressure mercury lamps as their lamp source, and the exposure method is omnidirectional irradiation. They have a wide spectral wavelength and low concentration, with a dominant wavelength of 365nm. LED exposure machines use LED lamps as their lamp source, and the exposure method is scanning. They have a narrow spectral wavelength and high concentration, with a dominant wavelength of 365nm or 395nm. LDI exposure machines use lasers as their lamp source, and the exposure method is scanning. They have a narrow spectral wavelength and high concentration, with a dominant wavelength of 355nm or 405nm.

[0004] Table 1

[0005] project UV exposure machine LED Exposure Machine LDI Exposure Machine Light source High-pressure mercury lamp LED lights laser Exposure method Aperture illumination method Scan Scan spectrum Wide wavelength, low concentration Narrow wavelength, high concentration Narrow wavelength, high concentration dominant wavelength 365nm 365 / 395nm 355 / 405nm

[0006] Currently, no single photocurable resin composition can be used simultaneously with all three types of exposure machines mentioned above. To improve the compatibility between photocurable resin compositions and exposure machines, it is urgent to research and develop a photocurable resin composition with excellent photosensitivity, resolution, and adhesion properties. Summary of the Invention

[0007] The main objective of this invention is to provide a photocurable resin composition and a photosensitive film to solve the problem that photocurable resin compositions in the prior art cannot simultaneously exhibit excellent photosensitivity, resolution, and adhesion at wavelengths of 355nm, 365nm, 395nm, and 405nm.

[0008] To achieve the above objectives, the present invention provides a photocurable resin composition, comprising, by weight: 30-70 parts of an alkali-soluble resin, 10-50 parts of a polymeric monomer, 0.5-10 parts of a photoinitiator, and 0.01-10 parts of an additive; the additive comprises a sulfur-containing compound of formula (I):

[0009]

[0010] Among them, R1 and R2 are each independently selected from C1 to C2. 12 Alkyl or C1-C 12 The alkoxy group; the sulfur content is 100 to 1000 ppm relative to the total weight of each gram of the light-cured resin composition.

[0011] Further, the weight ratio of the photoinitiator to the compound shown in formula (I) is (2.5 to 15):1; preferably, the photoinitiator includes 2,4,5-triarylimidazolium dimer and its derivatives; more preferably, the photoinitiator also includes one or more of the group consisting of tetraethylmielone, N-phenylglycine, acridine compounds, coumarin compounds, thiols, and pyrazoline compounds.

[0012] Furthermore, R1 and R2 are each independently selected from C1 to C5 straight-chain alkyl or branched-chain alkyl, or C1 to C5 alkoxy; preferably, R1 is selected from methyl, tert-butyl or methoxy; R2 is selected from methyl, tert-butyl or methoxy; preferably, R1 and R2 are the same.

[0013] Further, the compound shown in formula (I) is selected from one or more of the group consisting of 2,5-bis(5-tert-butyl-1,3-benzoxazol-2-yl)thiophenol, 2,5-bis(5-methyl-1,3-benzoxazol-2-yl)thiophenol and 2,5-bis(5-methoxy-1,3-benzoxazol-2-yl)thiophenol.

[0014] Further, by weight, the photocurable resin composition includes 0.2 to 1 part of a sulfur-containing compound of formula (I).

[0015] Furthermore, the weight-average molecular weight of the alkali-soluble resin is 30,000 to 150,000, preferably 60,000 to 120,000; the acid value of the alkali-soluble resin is 120 to 200 mg KOH / g.

[0016] Further, the polymerizable monomers include one or more of the following groups: nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionylphenol acrylate, ethoxylated propionyl dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionyl trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0017] Further, the alkali-soluble resin is selected from carboxyl-containing vinyl resins, which are obtained by copolymerization of unsaturated carboxylic acids and vinyl compounds; preferably, the unsaturated carboxylic acid is selected from one or more of the group consisting of (meth)acrylic acid, butenoic acid, isobutenoic acid, maleic acid, maleic anhydride, itaconic acid, and crotonic acid; preferably, the vinyl compound is selected from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, lauryl (meth)acrylate, and deca(meth)acrylate. One or more of the following groups: octaacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, benzyl methacrylate, styrene, α-methylstyrene, hydroxystyrene, methacrylamide, N-hydroxymethylacrylamide, N-butoxymethylacrylamide, phenoxyethyl (meth)acrylate, (alkoxylated)nonylphenol (meth)acrylate, ethyl N,N-dimethyl (meth)acrylate, ethyl N,N-diethyl (meth)acrylate, propyl N,N-dimethyl (meth)acrylate, and propyl N,N-diethyl (meth)acrylate.

[0018] Furthermore, the additives also include one or more of the following groups: adhesion promoters, plasticizers, dyes, fillers, flame retardants, stabilizers, leveling agents, peeling promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents.

[0019] To achieve the above objectives, another aspect of the present invention provides a photosensitive film, which includes at least a support film and a photosensitive layer disposed on one side surface of the support film. The photosensitive layer is made using the photocurable resin composition provided in this application. Preferably, a protective film is also disposed on the side surface of the photosensitive layer away from the support film.

[0020] Applying the technical solution of this invention, the above-mentioned photocurable resin composition contains sulfur-containing additives with the specific structure described above, which exhibit strong ultraviolet absorption in the 355-405 nm wavelength range, and particularly excellent photosensitivity at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm, thereby enhancing photosensitivity. Furthermore, limiting the sulfur content within the above range compared to other ranges is beneficial for balancing photosensitivity, resolution, and adhesion properties (especially adhesion on PCB copper plates), thereby improving the photosensitivity, resolution, and adhesion properties of the photocurable composition at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm. In addition, the compound of formula (I) containing the above-mentioned substituents exhibits excellent hydrophilicity, thereby reducing precipitates during the development process.

[0021] In summary, the photocurable resin composition provided in this application can be applied to three different types of exposure machines, including UV exposure machines, LED exposure machines and LDI exposure machines, and has good photosensitivity, resolution and adhesion properties. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0023] As described in the background section, existing photocurable resin compositions suffer from the problem of simultaneously exhibiting excellent photosensitivity, resolution, and adhesion properties at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm. To address these technical problems, this application provides a photocurable resin composition, comprising, by weight: 30–70 parts of an alkali-soluble resin, 10–50 parts of a polymeric monomer, 0.5–10 parts of a photoinitiator, and 0.01–10 parts of an additive; the additive comprises a sulfur-containing compound of formula (I). Among them, R1 and R2 are each independently selected from C1 to C2. 12 Alkyl or C1-C 12 The alkoxy group; the sulfur content is 100 to 1000 ppm relative to the total weight of each gram of the photocurable resin composition.

[0024] The aforementioned photocurable resin composition contains sulfur-containing additives with the specific structure described above, exhibiting strong ultraviolet absorption in the 355–405 nm wavelength range, particularly demonstrating excellent photosensitivity at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm, thereby enhancing photosensitivity. Furthermore, limiting the sulfur content within the aforementioned range, compared to other ranges, is beneficial for balancing photosensitivity, resolution, and adhesion properties (especially adhesion on PCB copper boards), thus improving the photosensitivity, resolution, and adhesion properties of the photocurable composition at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm. In addition, the compound of formula (I) containing the aforementioned substituents exhibits excellent hydrophilicity, thereby reducing precipitates during the development process.

[0025] In summary, the photocurable resin composition provided in this application can be applied to three different types of exposure machines, including UV exposure machines, LED exposure machines and LDI exposure machines, and has good photosensitivity, resolution and adhesion properties.

[0026] In a preferred embodiment, the weight ratio of the photoinitiator to the compound shown in formula (I) is (2.5–15):1. The weight ratio of the photoinitiator to the compound shown in formula (I) includes, but is not limited to, the range described above. Limiting it to this range is beneficial for further enhancing the synergistic effect of the photoinitiator and the additive, and for further improving the photosensitivity, resolution, and adhesion properties of the photocurable composition at wavelengths of 355 nm, 365 nm, 395 nm, and 405 nm.

[0027] To further improve the photosensitivity, resolution, and adhesion properties of the photocurable composition, preferably, the photoinitiator includes 2,4,5-triarylimidazolium dimer and its derivatives; more preferably, the photoinitiator also includes one or more of the group consisting of tetraethylmielone, N-phenylglycine, acridine compounds, coumarin compounds, thiols, and pyrazoline compounds.

[0028] In a preferred embodiment, R1 and R2 are each independently, but not limited to, straight-chain alkyl or branched-chain alkyl groups of C1 to C5, or alkoxy groups of C1 to C5. Compared to other types, the use of the above-mentioned substituent groups R1 and R2 is beneficial to improve the hydrophilicity of the compound shown in formula (I), thereby helping to reduce precipitates during the development process.

[0029] To further improve the hydrophilicity of the compound shown in formula (I) and further reduce precipitates during the development process, preferably, R1 includes, but is not limited to, methyl, tert-butyl or methoxy; R2 includes, but is not limited to, methyl, tert-butyl or methoxy.

[0030] To facilitate the synthesis of the compound shown in formula (I) and improve the synthesis efficiency, preferably, R1 and R2 are the same.

[0031] In a preferred embodiment, the compound represented by formula (I) includes, but is not limited to, one or more of the group consisting of 2,5-bis(5-tert-butyl-1,3-benzoxazol-2-yl)thiophenol, 2,5-bis(5-methyl-1,3-benzoxazol-2-yl)thiophenol, and 2,5-bis(5-methoxy-1,3-benzoxazol-2-yl)thiophenol. Compared to other types, the use of the above-mentioned substituents R1 and R2 is beneficial to further enhance the hydrophilicity of the compound represented by formula (I), thereby further reducing precipitates during the development process.

[0032] In order to further improve the photosensitivity, resolution and adhesion properties of the photocurable composition, and at the same time further reduce the precipitation during the development process, in a preferred embodiment, the photocurable resin composition includes 0.2 to 1 part by weight of the compound shown in formula (I).

[0033] In a preferred embodiment, the weight-average molecular weight of the alkali-soluble resin is 30,000 to 150,000, preferably 60,000 to 120,000. The weight-average molecular weight of the alkali-soluble resin includes, but is not limited to, the above range. Limiting it to this range is beneficial for improving masking ability, suppressing edge blending, and improving developability.

[0034] It should be noted that the weight-average molecular weight in this application was determined by gel permeation chromatography (GPC) and converted using a calibration curve of standard polymethyl methacrylate (refer to SN / T 4183-2015).

[0035] In a preferred embodiment, the acid value of the alkali-soluble resin is 120–200 mg KOH / g. The acid value of the alkali-soluble resin includes, but is not limited to, the above range. Limiting it to this range is beneficial for improving alkali solubility, thereby shortening the development and stripping times; it also helps to improve the resolution of the photocurable resin composition.

[0036] In a preferred embodiment, the polymeric monomer comprises one or more of the following groups: nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionic nonylphenol acrylate, ethoxylated propionic dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionic trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. The polymeric monomers include, but are not limited to, the types described above; limiting them to this range is beneficial for improving the photosensitivity of the photocurable resin composition.

[0037] In a preferred embodiment, the alkali-soluble resin includes, but is not limited to, carboxyl-containing vinyl resins, which are obtained by copolymerization of unsaturated carboxylic acids and vinyl compounds.

[0038] Preferably, the unsaturated carboxylic acids include, but are not limited to, one or more of the group consisting of (meth)acrylic acid, butenoic acid, isobutenoic acid, maleic acid, maleic anhydride, itaconic acid, and crotonic acid; the vinyl compounds include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, styrene, α-methylstyrene, hydroxystyrene, (meth)acrylamide, N-hydroxymethyl-acrylamide, N-butoxymethyl-acrylamide, phenoxyethyl (meth)acrylate, (alkoxylated)nonylphenol (meth)acrylate, N,N-dimethyl (meth)acrylate, N,N-diethyl (meth)acrylate, ethyl (meth)acrylate, N,N-dimethyl (meth)acrylate, propyl (meth)acrylate, and N,N-diethyl (meth)acrylate.

[0039] To further improve the photosensitivity of the photocurable resin composition, preferably, the styrene content in the alkali-soluble resin is ≤15wt%.

[0040] In a preferred embodiment, the additive further includes one or more of the following groups: adhesion promoter, plasticizer, dye, filler, flame retardant, stabilizer, leveling agent, peeling promoter, antioxidant, fragrance, imaging agent, and thermal crosslinking agent.

[0041] A second aspect of this application also provides a photosensitive film, which includes at least a support film and a photosensitive layer disposed on one side surface of the support film. The photosensitive layer is made using the photocurable resin composition described above provided in this application. Preferably, a protective film is disposed on the side surface of the photosensitive layer away from the support film.

[0042] The photocurable resin composition provided in this application exhibits photosensitivity, resolution, and adhesion properties at wavelengths of 355nm, 365nm, 395nm, and 405nm. It can be applied to three different types of exposure machines, including UV exposure machines, LED exposure machines, and LDI exposure machines. Its application in printed circuit boards can significantly improve the production efficiency of photosensitive films.

[0043] In a preferred embodiment, the protective film is a release film.

[0044] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0045] The types, sources, and corresponding numbers of the alkali-soluble resins, polymeric monomers, photoinitiators, and additives used in all the above embodiments and comparative examples of this application are as follows.

[0046] 1. Alkali-soluble resin

[0047] The polymer was prepared by solution polymerization, the process of which included: adding 120 mL of butanone to a 500 mL four-necked flask equipped with a heating device, a stirrer, a serpentine condenser, a constant-pressure dropping funnel, and a thermometer under a nitrogen atmosphere; adding all monomers used in the polymer formulation (see Table 2) with a total mass of 100 g; turning on the stirring device and raising the temperature of the heating device to 80 °C; then, under a nitrogen atmosphere, slowly adding 30 mL of butanone solution containing 0.8 g of azobisisobutyronitrile to the reaction flask dropwise for about 1.5 h; after the addition was completed, maintaining the temperature for another 4 h; then, dissolving 0.6 g of azobisisobutyronitrile in 40 mL of butanone and adding it dropwise to the reaction solution in two portions, each dropwise for 15 min; after the first dropwise addition, maintaining the temperature for 1 h before the second dropwise addition; after the second dropwise addition, maintaining the temperature for another 2 h; stopping heating and stirring, cooling to room temperature, and removing the reaction solution to obtain an alkali-soluble polymer resin solution.

[0048] The main components are as follows: methacrylic acid / methyl methacrylate / butyl methacrylate / styrene = 25 / 45 / 23 / 7 (weight average molecular weight is 107000, acid value is 163mgKOH / g), which is denoted as A.

[0049] 2. Photopolymerizable monomers

[0050] B-1: (4) Ethoxy-nonylphenol acrylate (strong electron);

[0051] B-2: (6) Ethylene oxide (12) propionylene oxide dimethacrylate (strong electron);

[0052] B-3: (10) Bisphenol A dimethacrylate ester (Sartoma);

[0053] B-4: (9) Ethylene oxide trimethylolpropane triacrylate (Sartoma).

[0054] 3. Photoinitiator

[0055] C-1: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole (strong electron);

[0056] C-2: 4,4'-bis(diethylamino)benzophenone (Aldrich);

[0057] C-3: N-phenylglycine (Aldrich).

[0058] 4. Additives

[0059] 4-1. The compound shown in formula (I)

[0060] D-1: 2,5-bis(5-tert-butyl-1,3-benzoxazol-2-yl)thiophenol;

[0061] D-2: 2,5-bis(5-methyl-1,3-benzoxazol-2-yl)thiophenol;

[0062] D-3: 2,5-bis(5-methoxy-1,3-benzoxazol-2-yl)thiophenol;

[0063] The synthesis method of D-1 is as follows: 2 mol of o-amino-p-tert-butylphenol and 1 mol of 2,5-thiophene dicarboxyl group are mixed in trichlorobenzene. 2.5 mol of phosphorus trichloride is added at 40-50℃. After reacting for 1 h, a catalytic amount of boric acid is added, and the temperature is raised to reflux. The reaction is carried out for 4-5 h. After the reaction is completed, trichlorobenzene is removed by steam distillation. The crude product is recrystallized with chlorobenzene or other solvents to obtain 2,5-bis(5-tert-butyl-1,3-benzoxazol-2-yl)thiophenol, which is designated as D-1.

[0064] According to the above synthesis method, replacing o-amino-p-tert-butylphenol with 2-amino-4-methylphenol can prepare 2,5-bis(5-methyl-1,3-benzoxazol-2-yl)thiophenol, denoted as D-2;

[0065] Following the above synthetic method, replacing o-amino-p-tert-butylphenol with 2-amino-4-methoxyphenol can yield 2,5-bis(5-methoxy-1,3-benzoxazol-2-yl)thiophenol, denoted as D-3.

[0066] 4-2. Dyes

[0067] E-1: Brilliant Green (Aldrich);

[0068] E-2: Aldrich crystal violet.

[0069] The formulations of the photocurable resin compositions provided in Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 2.

[0070] Table 2

[0071]

[0072] The following describes the sample preparation methods (including film application, exposure, and development), sample evaluation methods, and evaluation results for Examples 1 to 5 and Comparative Examples 1 to 2.

[0073] (1) Sample preparation method

[0074] [Screen Film Application] The screen protector was applied using a Changzhou Changyao Electronics CYL-M25, with an application pressure of 4 kg / cm². 2 The speed is 1 m / min and the temperature is 110℃.

[0075] [Exposure] After the film is applied, the sample is left to stand for more than 15 minutes. Exposure is performed using a UV exposure machine, an LED exposure machine, and an LDI exposure machine. The UV exposure machine model is Zhisheng UVE-M552, the LED exposure machine model is Hongshengxiang HSX-LEDS5, and the LDI exposure machine model is ADTEC IP-6. The exposure grid number is measured using a Stouffer 41-step exposure ruler, and the exposure grid number is controlled between 17 and 23 grids.

[0076] [Development] After exposure, allow the sample to stand for at least 15 minutes. The development temperature is 30℃, and the pressure is 1.5 kg / cm². 2 The developer is a 1.0 wt% sodium carbonate aqueous solution, and the development time is 1.5 to 2.0 times the minimum development time. After development, the product is washed with water and dried.

[0077] (2) Evaluation Methods

[0078] [Evaluation of the photosensitivity of the UV exposure machine] After applying the film, let it stand for 15 minutes before exposure. A Zhisheng UVE-M552 exposure machine was used, with an exposure energy of 25 mJ / cm². 2 The higher the exposure grid number, the better the photosensitivity.

[0079] [Evaluation of the photosensitivity of the LED exposure machine] After applying the film, let it stand for 15 minutes and then expose it. Use the Hongshengxiang HSX-LEDS5 exposure machine with an exposure intensity of 40% and an exposure time of 4 seconds. The higher the exposure grid number, the better the photosensitivity.

[0080] [Evaluation of the photosensitivity of the LDI exposure machine] After applying the film, let it stand for 15 minutes before exposure. An ADTEC IP-6 exposure machine was used with an exposure energy of 40 mJ / cm². 2 The higher the exposure grid number, the better the photosensitivity.

[0081] [Analysis Evaluation] Using a wiring pattern with equal line spacing and width of Line / Space = 10 / 10-70 / 70μm (increasing by 2.5μm each time), exposure and development were performed. After washing and drying, the pattern was observed with a magnifying glass. The minimum width of the normally formed cured resist line was recorded as the analysis value.

[0082] [Evaluation of Adhesion] Using a line spacing of Line / Space = n / 400μm (n ranges from 10 to 70, increasing by 2.5 each time) and different line width wiring patterns, exposure and development were performed. After washing and drying, the patterns were observed with a magnifying glass. The minimum width of the line that formed a complete cured resist was recorded as the adhesion value.

[0083] (3) Evaluation results of performance such as photosensitivity, resolution, and adhesion (see Table 3)

[0084] Table 3

[0085] Test Project Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 UV photosensitivity 20 20 20 17 23 16 25 Analysis (μm) 40 40 37.5 42.5 40 50 50 Adhesion (μm) 40 40 37.5 42.5 35 50 30 LED photosensitivity 20 20 20 17 23 15 25 Analysis (μm) 37.5 37.5 35 40 40 50 50 Adhesion (μm) 37.5 37.5 35 40 35 50 30 LDI photosensitivity 20 20 20 17 23 15 25 Analysis (μm) 30 30 27.5 32.5 35 40 50 Adhesion (μm) 30 30 27.5 32.5 27.5 40 25

[0086] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: the above-described photocurable resin composition contains sulfur-containing additives with the specific structure described above, which have strong ultraviolet absorption in the 355-405nm wavelength range, and especially exhibit excellent photosensitivity at wavelengths of 355nm, 365nm, 395nm, and 405nm, thereby enhancing photosensitivity. Moreover, compared to other ranges, limiting the sulfur content within the above range is beneficial for balancing photosensitivity, resolution performance, and adhesion performance (especially adhesion on PCB copper boards), thereby improving the photosensitivity, resolution performance, and adhesion performance of the photocurable composition at wavelengths of 355nm, 365nm, 395nm, and 405nm. In addition, the compound of formula (I) containing the above-described substituents has excellent hydrophilicity, thereby reducing precipitates during the development process.

[0087] In summary, the photocurable resin composition provided in this application can be applied to three different types of exposure machines, including UV exposure machines, LED exposure machines and LDI exposure machines, and has good photosensitivity, resolution and adhesion properties.

[0088] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photocurable resin composition, characterized in that, By weight, the photocurable resin composition comprises: 30-70 parts of alkali-soluble resin, 10-50 parts of polymeric monomer, 0.5-10 parts of photoinitiator, and 0.01-10 parts of additive; the additive comprises a sulfur-containing compound of formula (I): （I）， Among them, R1 and R2 are each independently selected from C1 to C2. 12 alkoxy groups; The sulfur content is 100 to 1000 ppm relative to the total weight of each gram of the photocurable resin composition.

2. The photocurable resin composition according to claim 1, characterized in that, The weight ratio of the photoinitiator to the compound shown in formula (I) is (2.5–15):

1.

3. The photocurable resin composition according to claim 1, characterized in that, The photoinitiator includes 2,4,5-triarylimidazolium dimer and its derivatives.

4. The photocurable resin composition according to claim 1, characterized in that, The photoinitiator also includes one or more of the following groups: tetraethylmielone, N-phenylglycine, acridine compounds, coumarin compounds, thiols, and pyrazoline compounds.

5. The photocurable resin composition according to claim 1, characterized in that, R1 and R2 are each independently selected from C1 to C5 alkoxy groups.

6. The photocurable resin composition according to claim 5, characterized in that, R1 is selected from methoxy; R2 is selected from methoxy.

7. The photocurable resin composition according to claim 5, characterized in that, R1 and R2 are the same.

8. The photocurable resin composition according to claim 1, characterized in that, The compound represented by formula (I) is selected from 2,5-bis(5-methoxy-1,3-benzoxazol-2-yl)thiophenol.

9. The photocurable resin composition according to any one of claims 1 to 8, characterized in that, The photocurable resin composition comprises, by weight, 0.2 to 1 part of the sulfur-containing compound shown in formula (I).

10. The photocurable resin composition according to claim 1, characterized in that, The weight-average molecular weight of the alkali-soluble resin is 30,000 to 150,000; the acid value of the alkali-soluble resin is 120 to 200 mg KOH / g.

11. The photocurable resin composition according to claim 10, characterized in that, The weight-average molecular weight of the alkali-soluble resin is 60,000 to 120,000.

12. The photocurable resin composition according to claim 1, characterized in that, The polymeric monomers include one or more of the following groups: nonylphenol acrylate, ethoxylated nonylphenol acrylate, ethoxylated propionylphenol acrylate, ethoxylated propionyl dimethacrylate, bisphenol A dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propionyl trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

13. The photocurable resin composition according to claim 12, characterized in that, The alkali-soluble resin is selected from carboxyl-containing vinyl resins, which are obtained by copolymerization of unsaturated carboxylic acids and vinyl compounds.

14. The photocurable resin composition according to claim 13, characterized in that, The unsaturated carboxylic acid is selected from one or more of the group consisting of (meth)acrylic acid, butenoic acid, isobutenoic acid, maleic acid, maleic anhydride, itaconic acid, and crotonic acid.

15. The photocurable resin composition according to claim 13, characterized in that, The vinyl compound is selected from one or more of the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, lauryl methacrylate, octadecyl methacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, benzyl methacrylate, styrene, α-methylstyrene, hydroxystyrene, methacrylamide, N-hydroxymethylacrylamide, N-butoxymethylacrylamide, phenoxyethyl methacrylate, nonylphenol methacrylate, alkoxylated nonylphenol methacrylate, N,N-dimethyl methacrylate, N,N-diethyl methacrylate, propyl methacrylate, and N,N-diethyl methacrylate.

16. The photocurable resin composition according to claim 1, characterized in that, The additives also include one or more of the following groups: adhesion promoters, plasticizers, dyes, fillers, flame retardants, stabilizers, leveling agents, peel promoters, antioxidants, fragrances, imaging agents, and thermal crosslinking agents.

17. A photosensitive film, characterized in that, The photosensitive film includes at least a support film and a photosensitive layer disposed on one side surface of the support film, wherein the photosensitive layer is made of the photocurable resin composition according to any one of claims 1 to 16.

18. The photosensitive film according to claim 17, characterized in that, A protective film is also provided on the surface of the photosensitive layer away from the support film.

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