Photosensitive resin composition, photosensitive dry film, cured film, circuit board, display module

Abstract

The present application provides a photosensitive resin composition, a photosensitive dry film, a cured film, a printed wiring board, and a display module. The photosensitive resin composition comprises, by weight parts, 100-115 parts of an alkali-soluble resin, 5-20 parts of a photopolymerization monomer, 3-10 parts of a terminal thiol-containing ester compound, 1-5 parts of a photoinitiator, and 10-30 parts of an epoxy resin; wherein the epoxy resin comprises a sulfur-containing epoxy resin. By controlling the types and contents of the components of the photosensitive resin composition within the above ranges, the surface layer and the deep layer of the cured film can be uniformly cured even if the curing time is short in the photocuring and thermal curing processes, and the photosensitive resin composition also has high photosensitivity, heat resistance, and good developing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photosensitive resin compositions, in particular, relates to a photosensitive resin composition, a photosensitive dry film, a cured film, a printed circuit board and a display module. BACKGROUND

[0002] In electronic products, a solder resist layer is usually required to be covered on a printed circuit board (PCB) as a permanent protective film, which not only prevents the circuit from corrosion and disconnection and short circuit between lines caused by too many soldering points, but also inhibits corrosion of the circuit substrate. The solder resist layer material is generally formed by a photosensitive resin composition after exposure and development to form a solder resist pattern, and then cured by heating. In order to play a permanent protective role and meet the subsequent PCB process, the solder resist layer material needs to have excellent heat resistance, hardness, scratch resistance, acid and alkali resistance, solvent resistance, cold and hot impact resistance, and warpage prevention, etc. At the same time, it also needs to have good exposure performance and alkali development ability.

[0003] In order to ensure the appearance of the solder resist layer, pigments and color powders are often added to change the color of the solder resist layer. However, some PCB products require a matte effect, which will affect the exposure performance of the solder resist layer, especially for black matte solder resist layer. The solder resist layer generally requires a high exposure energy, and the increase of exposure energy will also increase the exposure time, thereby seriously reducing the production efficiency of the solder resist layer. In addition, due to incomplete deep curing of the photosensitive resin composition, it will not only cause serious side etching and reduce the adhesion and windowing performance after development, but also cause problems such as plating leakage, solder resist layer blistering, warping and peeling in the subsequent process, thereby seriously affecting the performance of the PCB.

[0004] At present, the photosensitivity can be improved by increasing the content of photoinitiator in the photosensitive resin composition system, which can significantly reduce the exposure energy. However, as a small molecular compound, the photoinitiator will precipitate in the subsequent PCB nickel plating process, causing pollution of the nickel plating solution, thereby requiring frequent replacement of the solution, resulting in increased cost. At the same time, excessive photoinitiator in the photosensitive resin composition will also lead to reduced performance of the solder resist layer after photothermal curing. For the problem of side etching in the windowing area of the final solder resist layer caused by incomplete deep curing during photocuring, the use of high refractive index nano-inorganic fillers or modification of the photosensitive resin can improve the refractive index to achieve consistency of surface and deep curing. However, the high refractive index inorganic nano-filler is currently expensive and has poor dispersion effect in the resin and is prone to agglomeration. Modification of the photosensitive resin not only increases the process flow, but also increases the cost. SUMMARY

[0005] The present application aims to provide a photosensitive resin composition, a photosensitive dry film, a cured film, a circuit board and a display module to solve the problems of low photosensitivity, long exposure time, uneven curing of surface layer and deep layer and long heat curing time of the prior art photosensitive resin composition.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present application, a photosensitive resin composition is provided, which comprises, in parts by weight: 100-115 parts of alkali-soluble resin, 5-20 parts of photopolymerizable monomer, 3-10 parts of terminal mercapto-containing ester compound, 1-5 parts of photoinitiator and 10-30 parts of epoxy resin; wherein the epoxy resin comprises sulfur-containing epoxy resin.

[0007] Further, the mass ratio of the terminal mercapto-containing ester compound and the photopolymerizable monomer is 0.1-0.5:1; preferably, the parts by weight of the terminal mercapto-containing ester compound is 4-7 parts, and / or the parts by weight of the epoxy resin is 15-25 parts.

[0008] Further, the epoxy resin further comprises sulfur-free epoxy resin; wherein, based on the sum of the mass content of the ring sulfur group and the epoxy group in the epoxy resin being 100%, the mass ratio of the ring sulfur group and the epoxy group is 15-70:30-85, preferably 15-40:60-85.

[0009] Further, the photopolymerizable monomer is a multifunctional acrylate, preferably the photopolymerizable monomer is selected from any one or more of a di-functional monomer, a tri-functional monomer, a tetra-functional monomer, a penta-functional monomer, and a hexa-functional monomer; preferably the di-functional monomer is selected from any one or more of tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, (10) ethoxylated bisphenol A diacrylate, (10) propoxylated bisphenol A diacrylate, (10) ethoxylated propoxylated bisphenol A diacrylate, (4) ethoxylated bisphenol A diacrylate, (4) propoxylated bisphenol A diacrylate, ethoxylated propoxylated bisphenol A diacrylate, and tricyclodecane dimethanol diacrylate; preferably the tri-functional monomer is selected from any one or more of trimethylolpropane triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, (3) ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, (3) ethoxylated propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, ethoxylated propoxylated trimethylolpropane triacrylate, (6) ethoxylated trimethylolpropane triacrylate, (6) propoxylated trimethylolpropane triacrylate, and (6) ethoxylated propoxylated trimethylolpropane triacrylate; preferably the tetra-functional monomer is selected from any one or more of pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, and ethoxylated propoxylated pentaerythritol tetraacrylate; preferably the penta-functional monomer is dipentaerythritol pentaacrylate; preferably the hexa-functional monomer is dipentaerythritol hexaacrylate; and / or, the ratio of the total mass of the di-functional monomer and the tri-functional monomer to the total mass of the tetra-functional monomer and the hexa-functional monomer in the photopolymerizable monomer is 0.3-0.7: 1.2-3; and / or, the mass ratio of the di-functional monomer to the tri-functional monomer is 0.1-0.3: 0.5-1, and / or, the mass ratio of the tetra-functional monomer to the hexa-functional monomer is 0.3-0.5: 0.6-1.

[0010] Further, the terminal mercapto group-containing ester compound is an ester compound containing a terminal mercapto group, preferably the terminal mercapto group-containing ester compound is selected from any one or more of mercaptoacetic acid isooctyl ester, pentaerythritol tetra-3-mercaptopropionate, ethylene glycol bimerthiolate, glycerol mercaptoacetate, ethyl mercaptoacetate, butyl mercaptoacetate, isopropyl mercaptoacetate, 3-mercaptopropionic acid methyl ester, 3-mercaptopropionic acid butyl ester, and trimethylolpropane tris(3-mercaptopropionate); and / or, the alkali-soluble resin is a carboxyl group-containing epoxy acrylate resin; preferably the alkali-soluble resin is selected from any one or more of an acid-modified bisphenol A type epoxy acrylate resin, an acid-modified bisphenol F type epoxy acrylate resin, an acid-modified alicyclic epoxy acrylate resin, and an acid-modified phenol novolac epoxy acrylate resin; and / or, the photoinitiator is a free radical photoinitiator and / or a cationic photoinitiator; preferably the free radical photoinitiator is selected from any one or more of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl ethyl phenylphosphonate, 2-methyl-l-(4-methylthiophenyl)-2-morpholinopropanone, 2-isopropylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, tetramethylthioxanthone, tetraethylthioxanthone, 2-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2,4-diethylthioxanthone, benzoin dimethyl ether, 2-hydroxy-methylphenylpropan-l-one, 4-(N,N-dimethylamino)ethyl benzoate, and 2-hydroxy-2-methyl-l-[4-(2-hydroxyethoxy)phenyl]-l-propanone; and / or, the cationic photoinitiator is selected from any one or more of triphenylsulfonium hexafluorophosphate, 4-phenylthiophenyl diphenylsulfonium salt, 4-dodecyloxyphenyl diphenylsulfonium hexafluoroantimonate, bis[(4-diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, 4-phenylthiophenyl diphenylsulfonium salt, (4-hydroxyphenyl)methyl(benzyl)hexafluoroantimonate, 4-acetoxyphenyl dimethylsulfonium hexafluoroantimonate, and diphenyliodonium hexafluorophosphate.

[0011] Further, the preparation method of the sulfur-containing epoxy resin comprises: reacting raw materials including the sulfur-free epoxy resin, the sulfur-containing compound and the first solvent to obtain the sulfur-containing epoxy resin; wherein the sulfur-containing compound is potassium thiocyanate and / or thiourea; and / or the sulfur-free epoxy resin is selected from any one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenolic type epoxy resin, aliphatic glycidyl ether resin, brominated epoxy resin, glycidyl phthalate, glycidyl amine type epoxy resin, alicyclic epoxy resin, epoxidized olefin, hydantoin epoxy resin and imide epoxy resin; and / or the first solvent is water and / or ethanol solution; and / or the mass ratio of the sulfur-free epoxy resin and the sulfur-containing compound is 150-200:50-80; and / or the reaction temperature is 50-70 DEG C; and / or the reaction time is 300-600 min.

[0012] According to another aspect of the present application, there is provided a photosensitive dry film obtained by sequentially coating and drying a photosensitive resin composition.

[0013] According to still another aspect of the present application, there is provided a cured film obtained by sequentially coating, drying and curing a composition, or by curing a photosensitive dry film, wherein the composition is the photosensitive resin composition described above, and the photosensitive dry film is the photosensitive dry film described above, and wherein the curing comprises photocuring, thermocuring or photocuring and thermocuring.

[0014] According to still another aspect of the present application, there is provided a circuit board comprising the cured film described above.

[0015] According to still another aspect of the present application, there is provided a display module comprising the cured film described above.

[0016] According to the technical solution of the present application, the photosensitive resin composition of the present application uses an alkali-soluble resin as a base, and adds a photopolymerization monomer and a photoinitiator to enable the photosensitive resin composition to undergo a polymerization reaction under light irradiation; the thiol-terminated ester compound can act as a monomer component and react with an olefinic unsaturated bond, thereby improving the photosensitivity of the photosensitive resin composition, and also reducing the energy required in the photocuring process, thereby significantly reducing the exposure time in the photocuring process; the sulfur-containing epoxy resin acts as a thermocuring component in the photosensitive resin composition, and a thiol group (-SH) or a sulfur anion (S -) can promote the ring opening of epoxy groups, thereby promoting the curing reaction of epoxy resin with curing agent and alkali-soluble resin, and further improving the crosslinking network structure density, modulus and glass transition temperature of the cured photosensitive resin composition. By controlling the types and contents of the components of the photosensitive resin composition of the present application within the above ranges, the surface layer and deep layer of the cured film can be uniformly cured even if the curing time is short in the photo-curing and thermal curing process, and the photosensitivity, heat resistance and good developing performance are also high. DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0018] As analyzed in the background art of the present application, the photosensitive resin composition in the prior art has the problems of low photosensitivity, long exposure time, uneven curing of the surface layer and deep layer, and long thermal curing time. In order to solve the above problems, the present application provides a photosensitive resin composition, a photosensitive dry film, a cured film, a circuit board and a display module.

[0019] In a typical embodiment of the present application, a photosensitive resin composition is provided, which comprises, in parts by weight: 100-115 parts of alkali-soluble resin, 5-20 parts of photopolymerization monomer, 3-10 parts of end thiol-containing ester compound, 1-5 parts of photoinitiator, and 10-30 parts of epoxy resin; wherein the epoxy resin comprises sulfur-containing epoxy resin.

[0020] The photosensitive resin composition of the present application uses alkali-soluble resin as the base, and adds photopolymerization monomer and photoinitiator to enable the photosensitive resin composition to undergo polymerization reaction under light; the end thiol-containing ester compound can act as a monomer component to react with olefinic unsaturated bond, thereby improving the photosensitivity of the photosensitive resin composition, and also reducing the energy of the photosensitive resin composition in the photo-curing process, thereby significantly reducing the exposure time of the photo-curing process; the sulfur-containing epoxy resin as the thermal curing component in the photosensitive resin composition produces mercapto group (-SH) or sulfur negative ion (S - ) can promote the ring opening of epoxy groups, thereby promoting the curing reaction of epoxy resin with curing agent and alkali-soluble resin, and further improving the crosslinking network structure density, modulus and glass transition temperature of the cured photosensitive resin composition. By controlling the types and contents of the components of the photosensitive resin composition of the present application within the above ranges, the surface layer and deep layer of the cured film can be uniformly cured even if the curing time is short in the photo-curing and thermal curing process, and the photosensitivity, heat resistance and good developing performance are also high.

[0021] In an embodiment of the present application, the mass ratio of the terminal mercaptan-containing ester compound and the photopolymerization monomer is 0.1-0.5:1; in order to further improve the photosensitivity and curing uniformity of the photosensitive resin composition, preferably, the weight fraction of the terminal mercaptan-containing ester compound is 4-7 parts, and / or, the weight fraction of the epoxy resin is 15-25 parts.

[0022] Preferably, the mass ratio of the terminal mercaptan-containing ester compound and the photopolymerization monomer is controlled in the above range, which is helpful for the reaction of the mercapto group in the terminal mercaptan-containing ester compound with the unsaturated double bond in the photopolymerization monomer to form a crosslinked network during the photocuring process, and the high reactivity of the mercapto group in the terminal mercaptan-containing ester compound compared with the photopolymerization monomer is helpful for further improving the photosensitivity; meanwhile, the mass ratio of the terminal mercaptan-containing ester compound and the photopolymerization monomer that is too high is not conducive to the developability in the alkaline solution, and the mass ratio of the terminal mercaptan-containing ester compound and the photopolymerization monomer that is too low is not conducive to improving the photosensitivity of the photosensitive resin composition, therefore, preferably, the mass ratio of the terminal mercaptan-containing ester compound and the photopolymerization monomer is controlled in the above range, which is helpful for taking into account the developability and the photosensitivity of the photosensitive resin composition.

[0023] In an embodiment of the present application, the epoxy resin further comprises a sulfur-free epoxy resin: wherein, taking the sum of the mass content of the episulfide group and the epoxy group in the epoxy resin as 100%, the mass ratio of the episulfide group and the epoxy group is 15-70:30-85, preferably 15-40:60-85.

[0024] Preferably, the content ratio of the episulfide group and the epoxy group in the epoxy resin is controlled in the above range, which is helpful for further promoting the thermal curing reaction of the photosensitive resin composition, thereby helping to improve the heat resistance and acid and alkali resistance and other properties of the cured film obtained after the photosensitive resin composition is cured; too much content of the episulfide group in the epoxy resin is not only not conducive to the storage of the photosensitive resin composition, but also causes the refractive index of the epoxy resin to increase, resulting in a large difference in the refractive index between the epoxy resin and the filler in the auxiliary, thereby causing the surface layer and the deep layer of the photosensitive resin composition to be photocured unevenly, and further increasing the side etching of the pattern edge of the cured film; too little content of the episulfide group is not conducive to the thermal curing reaction, thereby reducing the degree of crosslinking reaction, and further reducing the heat resistance, acid and alkali resistance and other properties of the cured film, therefore, by controlling the content ratio of the episulfide group and the epoxy group in the sulfur-containing epoxy resin in the above range, it is helpful for the thermal curing reaction of the photosensitive resin composition, thereby helping the surface layer and the deep layer of the cured film to be cured uniformly and improving the heat resistance, acid and alkali resistance and other properties of the cured film.

[0025] In one embodiment of the present application, the photopolymerization monomer is a multifunctional acrylate, preferably, the photopolymerization monomer is selected from any one or more of a di-functional monomer, a tri-functional monomer, a tetra-functional monomer, a penta-functional monomer and a hexa-functional monomer; preferably the di-functional monomer is selected from any one or more of tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, (10) ethoxylated bisphenol A diacrylate, (10) propoxylated bisphenol A diacrylate, (10) ethoxylated propoxylated bisphenol A diacrylate, (4) ethoxylated bisphenol A diacrylate, (4) propoxylated bisphenol A diacrylate, ethoxylated propoxylated bisphenol A diacrylate and tricyclodecane dimethanol diacrylate; preferably the tri-functional monomer is selected from any one or more of trimethylolpropane triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, (3) ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, (3) ethoxylated propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, ethoxylated propoxylated trimethylolpropane triacrylate, (6) ethoxylated trimethylolpropane triacrylate, (6) propoxylated trimethylolpropane triacrylate and (6) ethoxylated propoxylated trimethylolpropane triacrylate; preferably the tetra-functional monomer is selected from any one or more of pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate and ethoxylated propoxylated pentaerythritol tetraacrylate; preferably the penta-functional monomer is dipentaerythritol pentaacrylate; preferably the hexa-functional monomer is dipentaerythritol hexaacrylate; and / or, the ratio of the total mass of the di-functional monomer and the tri-functional monomer to the total mass of the tetra-functional monomer and the hexa-functional monomer in the photopolymerization monomer is 0.3-0.7: 1.2-3; and / or, the mass ratio of the di-functional monomer to the tri-functional monomer is 0.1-0.3: 0.5-1, and / or, the mass ratio of the tetra-functional monomer to the hexa-functional monomer is 0.3-0.5: 0.6-1.

[0026] Preferably, the type of the photopolymerization monomer is controlled to be within the above range, and further, the ratio of the total mass of the di-functional monomer and the tri-functional monomer to the total mass of the tetra-functional monomer and the hexa-functional monomer, the mass ratio of the di-functional monomer to the tri-functional monomer and the mass ratio of the tetra-functional monomer to the hexa-functional monomer in the photopolymerization monomer are controlled to be within the above range, which helps to control the viscosity of the photosensitive resin composition, thereby facilitating subsequent coating processing and improving adhesion to the PCB, while the tetra-functional monomer and the hexa-functional monomer help to form a more compact crosslinked structure after the photosensitive resin composition is photo-thermally cured, thereby improving the heat resistance of the cured film. Herein, the functionality in the photopolymerization monomer refers to the number of double bonds in the monomer molecule that can participate in the polymerization reaction.

[0027] In order to further improve the synergistic effect between the components of the photosensitive resin composition, in an embodiment of the present application, the thiol-terminated ester compound is an ester compound having a terminal thiol group, preferably the thiol-terminated ester compound is selected from any one or more of mercaptoacetic acid iso-octyl ester, pentaerythritol tetra-3-mercaptopropionate, ethylene glycol bimerthiolate, glyceryl mercaptoacetate, ethyl mercaptoacetate, butyl mercaptoacetate, isopropyl mercaptoacetate, 3-mercaptopropionic acid methyl ester, 3-mercaptopropionic acid butyl ester, and trimethylolpropane tri(3-mercaptopropionate); and / or, the alkali-soluble resin is a carboxyl-containing epoxy acrylate resin; preferably the alkali-soluble resin is selected from any one or more of an acid-modified bisphenol A type epoxy acrylate resin, an acid-modified bisphenol F type epoxy acrylate resin, an acid-modified alicyclic epoxy acrylate resin, and an acid-modified phenol novolac epoxy acrylate resin; and / or, the photoinitiator is a free radical photoinitiator and / or a cationic photoinitiator; preferably the free radical photoinitiator is selected from any one or more of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl ethyl phenylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone, 2-isopropylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, tetramethylthioxanthone, tetraethylthioxanthone, 2-chlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2,4-diethylthioxanthone, benzoin dimethyl ether, 2-hydroxy-methylphenylpropan-1-one, 4-(N,N-dimethylamino)ethyl benzoate, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone; and / or, the cationic photoinitiator is selected from any one or more of triphenylsulfonium hexafluorophosphate, 4-phenylthiophenyl diphenylsulfonium salt, 4-dodecyloxyphenyl diphenylsulfonium hexafluoroantimonate, bis[(4-diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, 4-phenylthiophenyl diphenylsulfonium salt, (4-hydroxyphenyl)methyl(benzyl)hexafluoroantimonate, 4-acetoxyphenyl dimethylsulfonium hexafluoroantimonate, and diphenyliodonium hexafluorophosphate.

[0028] Preferably, the photosensitive resin composition further comprises 1-7 parts by weight of a curing agent, preferably 2-5 parts by weight; and 47-80 parts by weight of an auxiliary agent, preferably 52-72 parts by weight; preferably the curing agent is selected from any one or more of a polyamine curing agent, an imidazole curing agent, an acid anhydride curing agent, a boron amine and its salt curing agent; preferably the curing agent is selected from any one or more of 2-methylimidazole, 2-ethylimidazole, 4,4'-diamino diphenyl ether, 4,4'-diamino diphenyl disulfide, 3-aminobenzylamine, m-phenylenediamine, 3-amino-5-mercapto-1,2,4-triazole, 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride, 1-tritylimidazole, 4-imidazole-1-phenylpropionone, 1-ethyl-3-methylimidazole tetrafluoroborate, 1-ethylimidazole, 1-allylimidazole, 2,4,5-triphenylimidazole, melamine, melamine phosphate, melamine phosphate, trichloromelamine, hexamethylenemelamine, 1,8-diazabicyclo[5,4,0]dodec-7-ene, 4-cyanobenzylamine, 4,4'-diaminodiphenyl sulfone, 1-ethyl-3-methylimidazolium dicyandiamide salt, 1-butyl-3-methylimidazolium dicyandiamide salt, boron trifluoride and boron trifluoride ethylamine complex; preferably the curing agent is an acid anhydride curing agent, and / or the mass ratio of the acid anhydride curing agent to the sulfur-containing epoxy resin is 2-5:15-25; preferably the auxiliary agent comprises a filler, a functional auxiliary agent and a second solvent; wherein the weight fraction of the filler is 15-40 parts, preferably 20-35 parts; the weight fraction of the functional auxiliary agent is 2-10 parts, preferably 2-7 parts; the weight fraction of the second solvent is 25-35 parts, preferably 30 parts; and / or the filler is an inorganic filler, preferably the inorganic filler is barium sulfate and / or silicon dioxide; and / or the functional auxiliary agent is selected from any one or more of carbon black, a colorant, a defoaming agent, an antioxidant and a leveling agent; and / or the second solvent is selected from any one or more of γ-butyrolactone, diethylene glycol monoethyl ether acetate, DBE, preferably γ-butyrolactone.

[0029] Preferably, the curing agent is an acid anhydride curing agent, which generally requires a higher curing temperature when used as a curing agent for epoxy resins, and requires tertiary amines, quaternary amine salts, boron amine complexes, metal organic complexes, etc. as accelerators; preferably the mass ratio of the acid anhydride curing agent to the sulfur-containing epoxy resin is controlled within the above range, the sulfur ring group of the sulfur-containing epoxy resin in the photosensitive resin composition is more active, and is more easily opened to generate a sulfur anion or a mercapto group and an oxygen anion, thereby facilitating acid anhydride reaction with the acid anhydride curing agent to generate a disulfide bond, promoting the generation of carboxylate in the acid anhydride curing agent, and further promoting the crosslinking reaction of the sulfur-containing epoxy resin with the acid anhydride curing agent or the alkali-soluble resin, and further, in a shorter time, forming a denser crosslinking network of the photosensitive resin composition.

[0030] The kind and weight percentage of the filler, functional aid and second solvent in the preferred aid are within the above-mentioned range, which is helpful to promote the sufficient mixing of the components of the photosensitive resin composition, thereby improving the synergistic effect of the components.

[0031] In one embodiment of the present application, the preparation method of the sulfur-containing epoxy resin comprises: reacting raw materials including sulfur-free epoxy resin, sulfur-containing compound and first solvent to obtain the sulfur-containing epoxy resin; wherein the sulfur-containing compound is potassium thiocyanate and / or thiourea; and / or the sulfur-free epoxy resin is selected from any one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenolic type epoxy resin, aliphatic glycidyl ether resin, brominated epoxy resin, glycidyl phthalate, glycidyl amine type epoxy resin, alicyclic epoxy resin, epoxidized olefin, hydantoin epoxy resin and imide epoxy resin; and / or the first solvent is water and / or ethanol solution; and / or the mass ratio of the sulfur-free epoxy resin and the sulfur-containing compound is 150-200:50-80; and / or the reaction temperature is 50-70℃; and / or the reaction time is 300-600min.

[0032] The sulfur-containing epoxy resin is synthesized by the reaction of the above-mentioned raw materials, and preferably the kind of the sulfur-containing compound, the sulfur-free epoxy resin and the first solvent, the mass ratio of the sulfur-free epoxy resin and the sulfur-containing compound, and the reaction temperature and time are controlled within the above-mentioned range, which is helpful to replace the oxygen atom of the epoxy resin with the sulfur atom of the sulfur-containing compound, thereby generating the sulfur-containing epoxy resin containing both ring sulfur group and epoxy group.

[0033] In another typical embodiment of the present application, a photosensitive dry film is provided, which is obtained by coating and drying in sequence from the photosensitive resin composition as described above. Preferably, the drying temperature is 85-100℃; and / or the drying time is 30-50min; and the thickness of the photosensitive dry film is 15-50μm.

[0034] The photosensitive dry film obtained by coating and drying in sequence from the photosensitive resin composition as described above has high photosensitivity and is easy to cure.

[0035] In another typical embodiment of the present application, a cured film is provided, which is obtained by coating, drying and curing in sequence from the composition as described above, or by curing the photosensitive dry film as described above, wherein the curing comprises photocuring, thermal curing or photo-thermal dual curing.

[0036] The curing film has a short curing time and can be uniformly cured in the surface layer and the deep layer. The curing refers to photo-thermal dual curing. When the curing film is used as a solder resist layer, some types of the solder resist layer can be photo-cured or thermally cured. Even a dark solder resist layer (black) has high photosensitivity, heat resistance, and good exposure performance and alkali developing ability. The thickness of the curing film is preferably in the above range, which can meet the requirements of the current circuit board for the curing film and improve the protection of the circuit board by the curing film.

[0037] In another typical embodiment of the present application, a circuit board is provided, which comprises the curing film as described above.

[0038] The circuit board comprising the curing film has good corrosion resistance, thereby preventing corrosion of the circuit and short circuit between lines caused by too many soldering points.

[0039] In another typical embodiment of the present application, a display module is provided, which comprises the curing film as described above.

[0040] The display module comprising the curing film has good display performance.

[0041] The beneficial effects of the present application will be further illustrated in the following examples.

[0042] Example 1

[0043] Preparation of sulfur-containing epoxy resin: 200 g of bisphenol A type epoxy resin BNE-186 (Changchun Chemical) was dissolved in 100 mL of ethanol solution and then added to a four-necked flask; 80 g of sulfur-containing compound potassium thiocyanate (KSCN) was dissolved in 80 mL of distilled water and 80 mL of ethanol solution, and then added to a dropping funnel fixed on the four-necked flask. The synthesis reaction was carried out by starting to drop and stirring at 50°C. After standing, the mixture was poured into a separatory funnel. When the resin layer and the solvent layer in the mixture could be completely separated, the supernatant was removed, and toluene solution was added to dissolve the lower resin layer. After the resin was dissolved, it was washed with sodium chloride (NaCl) solution and then with deionized water until the solution was alkaline. Finally, the toluene solvent in the solution was separated by using a rotary evaporator at a slow temperature rise, and a sulfur-containing epoxy resin was obtained.

[0044] The epoxy resin includes sulfur-containing epoxy resin and sulfur-free epoxy resin, and the mass ratio of the sulfur-containing group to the epoxy group in the epoxy resin is 60:40.

[0045] By weight, the photosensitive resin composition comprises: 100 parts of alkali-soluble resin anhydride-modified o-cresol epoxy acrylate resin (model PR3000, manufacturer: Shanghai Showa), 2 parts of photopolymerizable monomer 1,6-hexanediol diacrylate (manufacturer: Sartoma, trade name: SR238NS), 8 parts of photopolymerizable monomer pentaerythritol tetraacrylate (manufacturer: Sartoma, trade name: SR295NS), 3 parts of terminal thiol ester compound pentaerythritol tetra-3-mercaptopropionate (manufacturer: Aladdin), 2 parts of photoinitiator 2,4,6-trimethylbenzoyl diphenylphosphine oxide (manufacturer: Changzhou Qiangli, model: TR-TPO), 1 1 part photoinitiator 1-hydroxycyclohexylphenyl ketone (manufacturer: Changzhou Qiangli, model: TR-184), 1 part photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (manufacturer: Changzhou Qiangli, model: TR-907), 15 parts epoxy resin, 2 parts curing agent maleic anhydride (manufacturer: Aladdin), 20 parts inorganic filler barium sulfate (manufacturer: Sakai Chemicals, Japan, model: BF-20), 12 parts inorganic filler silica (manufacturer: Yishitong, model: NFS-200E), 1.5 parts carbon black (manufacturer: Bora Corporation, model: Raven2500), 1 part antioxidant (Manufacturer: BASF), 0.5 parts leveling agent (Manufacturer: BYK Chemical), 0.5 parts of defoamer octamethylcyclotetrasiloxane (manufacturer: Dow Chemical, model number SH-193) and 30 parts of the second solvent γ-butyrolactone.

[0046] Preparation of photosensitive dry film: According to the above-mentioned weight proportions, alkali-soluble resin and additives are added to the second solvent and mixed evenly. The mixture is then ground to a particle size of <10μm using a sand mill. Subsequently, photopolymerizable monomers, photoinitiators, epoxy resins and curing agents are added in sequence and mixed evenly. The photosensitive resin composition is then evenly coated onto a PET support film using a coating machine and dried to obtain a photosensitive dry film with a thickness of 25μm. The drying temperature is 85℃ and the drying time is 30min.

[0047] Example 2

[0048] The difference from Example 1 is that the photosensitive resin composition comprises, in parts by weight: 115 parts of alkali-soluble resin anhydride-modified o-cresol formaldehyde epoxy acrylic resin (PR3000, produced by Shanghai Showa), 4 parts of photopolymerization monomer 1,6-hexanediol diacrylate (SR238NS, produced by Sartomer), 10 parts of photopolymerization monomer pentaerythritol tetraacrylate (SR295NS, produced by Sartomer), 10 parts of thiol-terminated ester compound pentaerythritol tetra-3-mercaptopropionate (produced by Aldrich), 2 parts of photoinitiator 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TR-TPO, produced by Changzhou Qiangli), 1 part of photoinitiator 1-hydroxycyclohexyl phenyl ketone (TR-184, produced by Changzhou Qiangli), 2 parts of photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone (TR-907, produced by Changzhou Qiangli), 30 parts of epoxy resin, 7 parts of curing agent maleic anhydride (produced by Aldrich), 25 parts of inorganic filler barium sulfate (BF-20, produced by Nippon Soda), 15 parts of inorganic filler silicon dioxide (NFS-200E, produced by Yishitong), 3.5 parts of carbon black (Raven2500, produced by Bora), 2.5 parts of antioxidant IRGANOX 1076 (produced by BASF), 2.5 parts of leveling agent BYK-370 (produced by BYK-Chemie), 1.5 parts of defoaming agent octamethylcyclotetrasiloxane (SH-193, produced by Dow Chemical), and 30 parts of second solvent gamma-butyrolactone, to finally obtain a photosensitive resin composition and a photosensitive dry film.

[0049] Example 3

[0050] The difference from Example 1 is that 200 g of bisphenol A type epoxy resin BNE-186 (Changchun Chemical) and 80 g of sulfur-containing compound potassium thiocyanate (KSCN) are added to adjust the mass ratio of the cyclic sulfur group and the epoxy group in the sulfur-containing epoxy resin obtained in Example 1 to 30:70, to finally obtain a photosensitive resin composition and a photosensitive dry film.

[0051] Example 4

[0052] The difference from Example 1 is that 80 g of bisphenol A type epoxy resin BNE-186 (Changchun Chemical) is added to adjust the mass ratio of the cyclic sulfur group and the epoxy group in the sulfur-containing epoxy resin obtained in Example 1 to 30:70, to finally obtain a photosensitive resin composition and a photosensitive dry film.

[0053] Example 5

[0054] ​​The difference from Example 1 is that the mass ratio of the mass of the thio ring group and the mass of the epoxy group in the sulfur-containing epoxy resin obtained in Example 1 is adjusted by adding 40 g of a bisphenol A type epoxy resin BNE-186 (Changchun Chemical) and 40 g of an o-cresol type epoxy resin CNE-200ELB (Changchun Chemical) so that the mass ratio of the thio ring group and the epoxy group in the epoxy resin is 30:70, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0055] Example 6

[0056] The difference from Example 4 is that the mass ratio of the mass of the thio ring group and the mass of the epoxy group in the sulfur-containing epoxy resin obtained in Example 1 is adjusted by adding 130 g of a bisphenol A type epoxy resin BNE-186 (Changchun Chemical) so that the mass ratio of the thio ring group and the epoxy group is 5:95, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0057] Example 7

[0058] The difference from Example 1 is that the mass ratio of the total mass of the thiol-terminated ester compound pentaerythritol tetra-3-mercaptopropionate and the photopolymerization monomer (1,6-hexanediol diacrylate and pentaerythritol tetraacrylate) is 0.1:1, wherein the 1,6-hexanediol diacrylate is 5 parts, the pentaerythritol tetraacrylate is 15 parts, and the pentaerythritol tetra-3-mercaptopropionate is 4 parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0059] Example 8

[0060] The difference from Example 1 is that the mass ratio of the total mass of the thiol-terminated ester compound pentaerythritol tetra-3-mercaptopropionate and the photopolymerization monomer (1,6-hexanediol diacrylate and pentaerythritol tetraacrylate) is 0.5:1, wherein the 1,6-hexanediol diacrylate is 2 parts, the pentaerythritol tetraacrylate is 6 parts, and the pentaerythritol tetra-3-mercaptopropionate is 4 parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0061] Example 9

[0062] The difference from Example 1 is that the mass ratio of the total mass of the thiol-terminated ester compound pentaerythritol tetra-3-mercaptopropionate and the photopolymerization monomer (1,6-hexanediol diacrylate and pentaerythritol tetraacrylate) is 1:1, wherein the 1,6-hexanediol diacrylate is 2 parts, the pentaerythritol tetraacrylate is 4 parts, and the pentaerythritol tetra-3-mercaptopropionate is 6 parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0063] Example 10

[0064] The difference from Example 1 is that the photopolymerization monomer is a combination of a difunctional monomer 1,6-hexanediol diacrylate, a trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate, a tetrafunctional monomer pentaerythritol tetraacrylate, and a hexafunctional monomer dipentaerythritol hexaacrylate, the total mass of the difunctional monomer 1,6-hexanediol diacrylate and the trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate to the total mass of the tetrafunctional monomer pentaerythritol tetraacrylate and the hexafunctional monomer dipentaerythritol hexaacrylate is 0.3:3, wherein the 1,6-hexanediol diacrylate is 0.5 parts, the (3) ethoxylated trimethylolpropane triacrylate is 1 part, the pentaerythritol tetraacrylate is 4 parts, and the dipentaerythritol hexaacrylate is 11 parts in terms of parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0065] Example 11

[0066] The difference from Example 1 is that the photopolymerization monomer is a combination of a difunctional monomer 1,6-hexanediol diacrylate, a trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate, a tetrafunctional monomer pentaerythritol tetraacrylate, and a hexafunctional monomer dipentaerythritol hexaacrylate, the total mass of the difunctional monomer 1,6-hexanediol diacrylate and the trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate to the total mass of the tetrafunctional monomer pentaerythritol tetraacrylate and the hexafunctional monomer dipentaerythritol hexaacrylate is 0.7:1.2, wherein the 1,6-hexanediol diacrylate is 2 parts, the (3) ethoxylated trimethylolpropane triacrylate is 5 parts, the pentaerythritol tetraacrylate is 5 parts, and the dipentaerythritol hexaacrylate is 7 parts in terms of parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0067] Example 12

[0068] The difference from Example 1 is that the photopolymerization monomer is a combination of a difunctional monomer 1,6-hexanediol diacrylate, a trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate, a tetrafunctional monomer pentaerythritol tetraacrylate, and a hexafunctional monomer dipentaerythritol hexaacrylate, the total mass of the difunctional monomer 1,6-hexanediol diacrylate and the trifunctional monomer (3) ethoxylated trimethylolpropane triacrylate to the total mass of the tetrafunctional monomer pentaerythritol tetraacrylate and the hexafunctional monomer dipentaerythritol hexaacrylate is 1:1.2, wherein the 1,6-hexanediol diacrylate is 4 parts, the (3) ethoxylated trimethylolpropane triacrylate is 6 parts, the pentaerythritol tetraacrylate is 5 parts, and the dipentaerythritol hexaacrylate is 7 parts in terms of parts by weight, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0069] Example 13

[0070] The difference from Example 1 is that the mass ratio of the curing agent maleic anhydride and the sulfur-containing epoxy resin is 2:25, wherein the maleic anhydride is 2 parts and the sulfur-containing epoxy resin is 25 parts by weight fraction, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0071] Example 14

[0072] The difference from Example 1 is that the mass ratio of the curing agent maleic anhydride and the sulfur-containing epoxy resin is 5:15, wherein the maleic anhydride is 5 parts and the sulfur-containing epoxy resin is 15 parts by weight fraction, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0073] Example 15

[0074] The difference from Example 1 is that the mass ratio of the curing agent maleic anhydride and the sulfur-containing epoxy resin is 6:15, wherein the maleic anhydride is 6 parts and the sulfur-containing epoxy resin is 15 parts by weight fraction, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0075] Example 16

[0076] The difference from Example 1 is that the inorganic filler is barium sulfate and silicon dioxide, the functional auxiliary agent is carbon black, the antioxidant the leveling agent and the defoaming agent octamethylcyclotetrasiloxane, the second solvent is γ-butyrolactone, the total fraction of the inorganic filler is 15 parts by weight fraction, the total mass fraction of the functional auxiliary agent is 2 parts, and the fraction of the second solvent is 30 parts, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0077] Example 17

[0078] The difference from Example 1 is that the inorganic filler is barium sulfate and silicon dioxide, the functional auxiliary agent is carbon black, the antioxidant the leveling agent and the defoaming agent octamethylcyclotetrasiloxane, the second solvent is γ-butyrolactone, the total fraction of the inorganic filler is 45 parts by weight fraction, the total fraction of the functional auxiliary agent is 2 parts, and the fraction of the second solvent is 30 parts, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0079] Comparative Example 1

[0080] The difference from Example 4 is that the terminal mercaptan-containing ester compound pentaerythritol tetra-3-mercaptopropionate is not added, and finally the photosensitive resin composition and the photosensitive dry film are obtained.

[0081] Comparative Example 2

[0082] The difference from Example 4 is that 15 parts of thiol-terminated ester compound pentaerythritol tetra-3-mercaptopropionate (manufactured by Aldrich) is added, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0083] Comparative Example 3

[0084] The difference from Example 4 is that the sulfur-containing epoxy resin is replaced by bisphenol A epoxy resin BNE-186 (Changchun Chemical), and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0085] Comparative Example 4

[0086] The difference from Example 4 is that the curing temperature is 150°C and the curing time is 1 h, and finally a photosensitive resin composition and a photosensitive dry film are obtained.

[0087] Test method:

[0088] Test method for mass ratio of ring sulfur group and epoxy group in sulfur-containing epoxy resin: tested by infrared spectroscopy or nuclear magnetic quantitative analysis method.

[0089] 1) Sensitivity test:

[0090] A 25-μm photosensitive dry film is attached to a commercial copper-clad plate by using a vacuum film laminator, the pressure in the vacuum section is 6 kgf, the vacuum time is 20 s, the pressing time is 30 s, and the temperature is 65°C; the pressure in the flattening section is 6 kgf, the flattening time is 50 s, and the temperature is 85°C; after the attachment is completed, exposure and development are performed on an ST21 step exposure meter, and the lowest energy at which the ST8 step is not developed and completely exposed is the sensitivity energy of the formula.

[0091] 2) Line width and space (L / S), side etching, and minimum opening test:

[0092] A 25-μm photosensitive dry film is attached to a commercial copper-clad plate by using a vacuum film laminator, the pressure in the vacuum section is 6 kgf, the vacuum time is 20 s, the pressing time is 30 s, and the temperature is 65°C; the pressure in the flattening section is 6 kgf, the flattening time is 50 s, and the temperature is 85°C; after the attachment is completed, exposure is performed on a standard test mask film at the ST8 / 21 sensitivity energy, and after thermal curing, L / S and side etching are observed under a metallographic microscope by slicing, and the minimum opening can be directly observed under a metallographic microscope. When the line width and space and the opening diameter can completely present and the error is within ±5% of the standard mask film, the optimal L / S and minimum opening are achieved, at which time the size of the side etching is measured and recorded, and whether the side etching is within ±5% of the standard mask film is observed. The test results are graded as follows, first grade: error within ±5%; second grade: error within ±10% but outside ±5%; third grade: error outside ±10%.

[0093] 3) Surface flatness test after thermal curing:

[0094] A 25 pm photosensitive dry film was attached to a commercial copper clad board using a vacuum film laminator. The pressure in the vacuum section was 6 kgf, the vacuum time was 20 s, the pressing time was 30 s, and the temperature was 65 °C. The pressure in the flattening section was 6 kgf, the flattening time was 50 s, and the temperature was 85 °C. After the attachment was completed, the copper clad board with the photosensitive dry film was exposed to light under a high-pressure mercury lamp exposure machine. After the PET support film was peeled off, the film was exposed to light with appropriate energy. After exposure, the film was placed at room temperature for 30 min, then developed in an alkaline developer (1 wt% aqueous sodium carbonate solution) at 30 °C for 30 s. After development, the film was rinsed with water for 30 s to remove the residual developer on the surface of the film. Then the copper clad board with the attached film was post-cured in an oven at 150 °C for 30 min. The cured film on the copper clad board was observed under a microscope for cracking, wrinkling, and warping. The test results were graded as follows: first grade: flat surface, no wrinkles, cracks, or warping; second grade: surface with wrinkles, cracks, or warping.

[0095] 4) Glass transition temperature (Tg) and coefficient of thermal expansion (CTE) test:

[0096] A 50-μm-thick photosensitive dry film was attached to a commercial copper-clad board using a vacuum laminator, with a pressure of 6 kgf in the vacuum section, a vacuum time of 20 s, a pressing time of 30 s, and a temperature of 65°C; a pressure of 6 kgf in the flattening section, a flattening time of 50 s, and a temperature of 85°C. After the attachment, the entire board was exposed to light using ST8 / 21 sensitivity energy, and after exposure, the board was left to stand at room temperature for 30 min, then developed at 30°C for 30 s using an alkaline developer (1 wt% aqueous sodium carbonate solution), and then rinsed with water for 30 s to remove the developer remaining on the surface of the film. After that, the copper-clad board with the film attached was post-cured in an oven at 150°C for 30 min. Then, the product was cut into pieces of 5 mm in width and 25 mm in length using a cutting knife, and the PET support film of the cured film product was peeled off, to obtain a cured product of the photosensitive resin composition for evaluation of the coefficient of thermal expansion. The coefficient of thermal expansion under tension was measured using a TMA device (TMA Q400, Shenzhen Senter Scientific). The tension load was 0.1 N, the span (distance between the grips) was 15 mm, and the temperature increase rate was 10°C / min. First, the sample was installed on the device, and heated from room temperature (25°C) to 160°C and left to stand for 15 min. Then, it was cooled to -60°C, and the measurement was performed again under conditions of heating from -60°C to 250°C at a temperature increase rate of 10°C / min. The inflection point seen in the range from 25°C to 200°C was marked as Tg, and the temperature at this time was recorded. The CTE was calculated using the slope of the tangent line of the curve obtained at temperatures below Tg. The test results were ranked as follows: first class: less than 50 ppm / °C; second class: 50 to 60 ppm / °C; third class: 60 to 70 ppm / °C; and fourth class: more than 70 ppm / °C.

[0097] 5) Aging (HAST) test:

[0098] A 25 pm thick photosensitive dry film was attached to a commercial copper clad board using a vacuum laminator with a pressure of 6 kgf, a vacuum time of 20 s, a pressing time of 30 s, and a temperature of 65 °C. The flattening pressure was 6 kgf, the flattening time was 50 s, and the temperature was 85 °C. After the attachment, the entire board was exposed using ST8 / 21 sensitivity energy. After exposure, the board was left to stand at room temperature for 30 min, then developed at 30 °C for 30 s using an alkaline developer (1 wt% aqueous sodium carbonate solution). After development, the board was rinsed with water for 30 s to remove the residual developer from the surface of the film. The copper clad board with the attached film was then post-cured in an oven at 150 °C for 30 min. The resistivity of the cured film product before HAST treatment was measured using a resistance meter. The sample was then moved to a HAST chamber (PC-422R8D, Hirayama Mfg. Co., Ltd.) and left to stand at 121 °C and 100% humidity for 120 h. The resistivity after HAST treatment was measured again, and the presence or absence of phenomena such as blistering and peeling was observed. The change in resistivity before and after HAST was compared. The test results were classified as follows: first class: no phenomena such as blistering and peeling, or a change in resistivity of ±10% or less; second class: no phenomena such as blistering and peeling, or a change in resistivity of ±30% or less; third class: a small amount of blistering, peeling, or even peeling of the cured film; and fourth class: a large amount of blistering or peeling, or a change in resistivity of more than 50%.

[0099] 6) Acid resistance test:

[0100] Test samples were prepared using the above-described HAST test preparation method. The samples were immersed in a 10 vol% aqueous H2SO4 solution at 30 °C for 30 min, then rinsed with water and dried. The samples were then subjected to a 3M tape peeling test. The acid resistance was evaluated according to the following criteria. The test results were classified as follows: first class: no blistering, peeling, or even peeling of the cured film; second class: a small amount of blistering, no peeling, or no peeling of the cured film; third class: a small amount of blistering, peeling, or even peeling of the cured film; and fourth class: a large amount of peeling of the cured film.

[0101] 7) Alkali resistance test:

[0102] Test samples were prepared using the above-described HAST test preparation method. The samples were immersed in a 10 vol% aqueous NaOH solution at 30 °C for 30 min, then rinsed with water and dried. The samples were then subjected to a 3M tape peeling test. The alkali resistance was evaluated according to the following criteria. The test results were classified as follows: first class: no blistering, peeling, or even peeling of the cured film; second class: a small amount of blistering, no peeling, or no peeling of the cured film; third class: a small amount of blistering, peeling, or even peeling of the cured film; and fourth class: a large amount of peeling of the cured film.

[0103] 8) Solvent resistance test:

[0104] Test samples were prepared by the above-mentioned preparation method of HAST test, immersed in propylene glycol methyl ether acetate solvent at 30℃ for 30 min, dried and then peeled off by 3M tape for peeling test, and the solvent resistance was evaluated according to the following standards. The test results are divided into the following grades: first grade: the cured film is completely free of bubbling, peeling and even falling off; second grade: the cured film has a small amount of bubbling, no peeling and no falling off; third grade: the cured film has a small amount of bubbling, peeling and even falling off; fourth grade: the cured film has a large amount of falling off.

[0105] 9) Heat resistance test:

[0106] The test was carried out according to the IPC-TM650.2.6.8 standard. After the cured film was immersed in rosin flux for 30 s, it was vertically immersed in a tin furnace with a temperature of 288℃ for 10 s, and the process was repeated for 3 times. Whether the surface was bubbled, discolored or floated was observed, and whether the cured film was peeled off was observed by 3M tape peeling. The appearance change was evaluated according to the following standards. The test results are divided into the following grades: first grade: the cured film is completely free of bubbling, peeling and even falling off; second grade: the cured film has a small amount of bubbling, no peeling and no falling off; third grade: the cured film has a small amount of bubbling, peeling and even falling off; fourth grade: the cured film has a large amount of falling off.

[0107] The cured films obtained from the above examples and comparative examples were subjected to the above performance tests, and the test results are shown in Tables 1 and 2.

[0108] Table 1

[0109]

[0110]

[0111] Table 2

[0112]

[0113]

[0114] From the above description, it can be seen that the above-mentioned examples of the present application achieve the following technical effects:

[0115] ​The photosensitive resin composition of the present application uses alkali-soluble resin as the base, adds photopolymerization monomer and photoinitiator to enable the photosensitive resin composition to undergo polymerization reaction under light irradiation; contains terminal mercapto ester compound to act as monomer component and react with olefinic unsaturated bond, thereby improving photosensitivity of the photosensitive resin composition, and also reducing energy in the process of photocuring, thereby significantly reducing exposure time in the process of photocuring; contains sulfur-containing epoxy resin as the thermocuring component in the photosensitive resin composition, and the mercapto group (-SH) or sulfur negative ion (S - ) produced after ring-opening of the ring sulfur group in the sulfur-containing epoxy resin under heating condition can promote ring-opening of the epoxy group, thereby promoting curing reaction of the epoxy resin with the curing agent and alkali-soluble resin, and further improving the crosslinking network structure density, modulus and glass transition temperature of the photosensitive resin composition after curing. By controlling the types and contents of the components of the photosensitive resin composition of the present application within the above ranges, the surface layer and deep layer of the cured film can be uniformly cured even if the curing time is short in the process of photocuring and thermocuring, and the photosensitive resin composition also has high photosensitivity, heat resistance and good developing performance.

[0116] The above only describes the embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A photosensitive resin composition, characterized by comprising: The photosensitive resin composition comprises, in parts by weight: 100 to 115 parts of an alkali-soluble resin; 5 to 20 parts of a photopolymerization monomer; 3 to 10 parts of a terminal mercapto group-containing ester compound; 1 to 5 parts of a photoinitiator; and 10 to 30 parts of an epoxy resin; wherein the epoxy resin comprises a sulfur-containing epoxy resin.

2. The photosensitive resin composition according to claim 1, characterized by The mass ratio of the terminal mercapto group-containing ester compound to the photopolymerization monomer is 0.1 to 0.5:

1.

3. The photosensitive resin composition according to claim 1, characterized by The terminal mercapto group-containing ester compound is in an amount of 4 to 7 parts by weight, and / or the epoxy resin is in an amount of 15 to 25 parts by weight.

4. The photosensitive resin composition according to any one of claims 1 to 3, characterized by The epoxy resin further comprises a sulfur-free epoxy resin: wherein the mass ratio of the cyclic sulfur group to the epoxy group is 15 to 70:30 to 85, based on the sum of the mass content of the cyclic sulfur group and the epoxy group in the epoxy resin being 100%.

5. The photosensitive resin composition according to claim 4, characterized by The mass ratio of the cyclic sulfur group to the epoxy group is 15 to 40:60 to 85, based on the sum of the mass content of the cyclic sulfur group and the epoxy group in the epoxy resin being 100%.

6. The photosensitive resin composition according to any one of claims 1 to 3, characterized by The photopolymerization monomer is a multifunctional acrylate, and the photopolymerization monomer is selected from any one or more of a di-functional monomer, a tri-functional monomer, a tetra-functional monomer, a penta-functional monomer, and a hexa-functional monomer; and / or the ratio of the total mass of the di-functional monomer and the tri-functional monomer to the total mass of the tetra-functional monomer and the hexa-functional monomer is 0.3 to 0.7:1.2 to 3; and / or the mass ratio of the di-functional monomer to the tri-functional monomer is 0.1 to 0.3:0.5 to 1, and / or the mass ratio of the tetra-functional monomer to the hexa-functional monomer is 0.3 to 0.5:0.6 to 1.

7. The photosensitive resin composition according to claim 6, characterized by The di-functional monomer is selected from any one or more of tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, (10) ethoxylated bisphenol A diacrylate, (10) propoxylated bisphenol A diacrylate, (10) ethoxylated propoxylated bisphenol A diacrylate, (4) ethoxylated bisphenol A diacrylate, (4) propoxylated bisphenol A diacrylate, ethoxylated propoxylated bisphenol A diacrylate, and tricyclodecane dimethanol diacrylate.

8. The photosensitive resin composition according to claim 6, characterized by The tri-functional monomer is selected from any one or more of trimethylolpropane triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, (3) ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, (3) ethoxylated propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, (3) propoxylated trimethylolpropane triacrylate, ethoxylated propoxylated trimethylolpropane triacrylate, (6) ethoxylated trimethylolpropane triacrylate, (6) propoxylated trimethylolpropane triacrylate, and (6) ethoxylated propoxylated trimethylolpropane triacrylate.

9. The photosensitive resin composition according to claim 6, characterized by The tetra-functional monomer is selected from any one or more of pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, and ethoxylated propoxylated pentaerythritol tetraacrylate.

10. The photosensitive resin composition according to claim 6, characterized by The penta-functional monomer is dipentaerythritol pentaacrylate.

11. The photosensitive resin composition according to claim 6, characterized by The hexa-functional monomer is dipentaerythritol hexaacrylate.

12. The photosensitive resin composition according to any one of claims 1 to 3, characterized by The terminal thiol-containing ester compound is an ester compound containing a terminal thiol group; And / or, the alkali-soluble resin is a carboxyl-containing epoxy acrylate resin; And / or, the photoinitiator is a free radical photoinitiator and / or a cationic photoinitiator.

13. The photosensitive resin composition according to claim 12, characterized by The terminal thiol-containing ester compound is any one or more of mercaptoacetic acid isooctyl ester, pentaerythritol tetra-3-mercaptopropionate, ethylene glycol bimerthiolate, glycerol mercaptoacetate, ethyl mercaptoacetate, butyl mercaptoacetate, isopropyl mercaptoacetate, 3-mercaptopropionic acid methyl ester, 3-mercaptopropionic acid butyl ester, and trimethylolpropane tri(3-mercaptopropionate).

14. The photosensitive resin composition according to claim 12, characterized by The alkali-soluble resin is any one or more of acid-modified bisphenol A type epoxy acrylate resin, acid-modified bisphenol F type epoxy acrylate resin, acid-modified alicyclic epoxy acrylate resin, and acid-modified phenolic epoxy acrylate resin.

15. The photosensitive resin composition according to claim 12, characterized by The free radical photoinitiator is any one or more of 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl phenyl phosphine ethyl ester, 2-methyl-1-(4-methylthio phenyl)-2-morpholino-1-propanone, 2-isopropyl thioxanthone, 1-hydroxy cyclohexyl phenyl ketone, benzophenone, 4-methyl benzophenone, 2,4,6-trimethyl benzophenone, tetramethyl thioxanthone, tetraethyl thioxanthone, 2-chlorothioxanthone, 1-chloro-4-propoxy thioxanthone, 2,4-diethyl thioxanthone, benzoin dimethyl ether, 2-hydroxy-methyl phenyl propane-1-ketone, 4-(N,N-dimethylamino) benzene acid ethyl ester, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy) phenyl]-1-propanone; and / or, the cationic photoinitiator is any one or more of triphenyl sulfonium hexafluorophosphate, 4-phenylthio phenyl diphenyl sulfonium salt, 4-dodecyloxy phenyl diphenyl sulfonium hexafluoroantimonate, bis[(4-diphenyl sulfonium) benzene] sulfide-bis-hexafluorophosphate, 4-phenylthio phenyl diphenyl sulfonium salt, (4-hydroxy phenyl) methyl (benzyl) hexa sulfonium fluorophosphate, 4-acetoxy phenyl dimethyl sulfonium hexafluoroantimonate, and diphenyl iodonium hexafluorophosphate.

16. The photosensitive resin composition according to claim 4, characterized by The preparation method of the sulfur-containing epoxy resin comprises: reacting raw materials including the sulfur-free epoxy resin, a sulfur-containing compound, and a first solvent to obtain the sulfur-containing epoxy resin. The sulfur-containing compound is potassium thiocyanate and / or thiourea. And / or, the sulfur-free epoxy resin is a multifunctional resin; And / or, the first solvent is water and / or an ethanol solution; And / or, the mass ratio of the sulfur-free epoxy resin to the sulfur-containing compound is 150-200:50-80; And / or, the reaction temperature is 50-70°C; and / or, the reaction time is 300-600 min.

17. The photosensitive resin composition according to claim 16, characterized by The sulfur-free epoxy resin is selected from any one or more of bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, phenol-aldehyde type epoxy resins, aliphatic glycidyl ether resins, brominated epoxy resins, phthalic acid glycidyl esters, glycidyl amine type epoxy resins, alicyclic epoxy resins, epoxidized olefins, hydantoin epoxy resins, and imide epoxy resins.

18. A photosensitive dry film obtained by sequentially subjecting a photosensitive resin composition to coating and drying, characterized in that, The photosensitive resin composition is the photosensitive resin composition according to any one of claims 1 to 17.

19. A cured film obtained by successively coating, drying and curing a composition, or by curing a photosensitive dry film, characterized in that, The composition is the photosensitive resin composition according to any one of claims 1 to 17, and the photosensitive dry film is the photosensitive dry film according to claim 18, wherein the curing includes photocuring, thermocuring, or photo-thermo dual curing.

20. A wiring board comprising a cured film, characterized by, The cured film is the cured film according to claim 19.

21. A display module comprising a cured film, wherein, The cured film is the cured film according to claim 19.

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