Photopolymerization initiator and photocuring composition and application thereof

Abstract

The invention belongs to the technical field of photoinitiators, and particularly relates to a photopolymerization initiator and a photocuring composition and application thereof. According to the invention, C3-C20 heteroaryl groups containing sulfoxide or sulfone atoms are introduced into the main chain of ketoxime ester, so that the solubility and the light sensitivity of the photopolymerization initiator can be improved. The good solubility can ensure the uniform curing of the photopolymerization combination, so that the performance and appearance of the product are improved. Due to the excellent light sensitivity, light energy can be more effectively absorbed, rapid transition to an excited state is achieved, chemical reaction is initiated, the low energy threshold value and the high initiation efficiency are achieved, different illumination conditions are adapted, the photopolymerization efficiency and yield are improved, and the product application flexibility is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photoinitiators, and specifically relates to a photopolymerization initiator and a photocurable composition and application thereof. Background Art

[0002] Photopolymerization initiators (photosensitizers or photoinitiators) are a class of compounds that absorb specific wavelength energy in the 250-400nm spectral region and produce free radicals or cations, which in turn initiate monomer polymerization and cross-linking curing. As a key component of the photocuring system, although the amount of photopolymerization initiator is relatively low, it has a decisive influence on the photocuring rate and is related to the transition from liquid to solid. With the widespread application of photocuring technology in coatings, inks, microelectronics, printing and other fields, as well as the continuous development of UV-VIS LED light source curing technology, it has become particularly important to develop photopolymerization initiators suitable for UV-VIS LED light sources.

[0003] Traditional photocuring systems require a large amount of reactive diluents to reduce resin viscosity due to the poor solubility of photocatalysts. However, these monomers are volatile and may produce toxicity and odor, affecting the environment. In contrast, photocatalysts with good solubility are less likely to produce turbidity or precipitation, have higher stability, and require less solvent. Therefore, photocatalysts with good solubility have good application prospects due to their low pollution and stability. In addition, the mainstream photopolymerization initiators on the market are mostly benzoin derivatives, dibenzoyl derivatives, α-carboxyl ketones, and α-amino ketones. These types of photopolymerization initiators have slightly poor photosensitivity and have certain reproductive toxicity. There is an urgent need to develop photopolymerization initiators with excellent solubility and photosensitivity and low toxicity. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a photopolymerization initiator and a photocurable composition and application thereof. The present invention introduces a C3-C4-containing sulfoxide or sulfone atom into the main chain of the ketoxime ester. 20 Heteroaromatic groups can improve the photosensitivity of photopolymerization initiators. Their good solubility ensures uniform curing of the photopolymerization combination, thereby improving the performance and appearance of the product. The superior photosensitivity enables it to absorb light energy more effectively, quickly transition to the excited state and initiate chemical reactions, with a lower energy threshold and higher initiation efficiency, adapting to different lighting conditions, improving the efficiency and yield of photopolymerization, and increasing the flexibility of product application.

[0005] The technical solution provided by the present invention is as follows:

[0006] A photopolymerization initiator is a compound having a structure shown in chemical formula (I):

[0007]

[0008] R1 is C1-C12 Substituted or unsubstituted alkyl, C1-C 12 Substituted or unsubstituted alkoxy, C3-C 12 Substituted or unsubstituted cycloalkyl, C3-C 12 Substituted or unsubstituted heterocycloalkyl, C6-C 12 Heterocyclic aromatic or C6-C 12 a substituted or unsubstituted aryl group;

[0009] R2 is C1-C 12 Substituted or unsubstituted alkyl, C1-C 12 Substituted or unsubstituted alkoxy, C3-C 12 Cycloalkyl, C3-C 12 Substituted or unsubstituted heterocycloalkyl, C6-C 20 Substituted or unsubstituted aryl or C3-C 12 Heterocyclic aromatic groups;

[0010] L1 is a single bond or a carbonyl group;

[0011] Ar1 is hydrogen or an electron-withdrawing group;

[0012] Het1 is a C3-C 20 Heteroaromatic groups.

[0013] In the above technical solution:

[0014] By introducing a C3-C3-C3-sulfoxide or sulfone atom into the main chain of the ketoxime ester 20 The oxygen atom in the heteroaromatic group and the sulfone group has a lone pair of electrons, which can form p-π conjugation with the π orbital in the π electron system, resulting in delocalization of electrons in the entire molecule or molecular fragment, thereby reducing the intramolecular energy of the photopolymerization initiator, increasing stability, and improving photosensitivity.

[0015] Specific:

[0016] R1 is C1-C 12 Alkyl, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-, -CO-;

[0017] Or R1 is C1-C 12 Alkoxy, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-, -CO-;

[0018] Or R1 is C3-C 12The monocyclic alkyl of formula (I) is connected to the C1-C5 alkyl group via a single bond or a C1-C5 alkyl group, the C1-C5 alkyl group is unsubstituted or substituted by halogen, or is uninterrupted or is interrupted by one or more -O- groups;

[0019] Or R1 is C3-C 12 The monoheterocyclic alkyl group of the present invention is a monoheterocyclic alkyl group, the methylene group on the ring may be interrupted by one or more -O- groups, the monoheterocyclic alkyl group is connected to the chemical formula (I) via a single bond or a C1-C5 alkyl group, the C1-C5 alkyl group is unsubstituted or substituted by halogen, or is uninterrupted or interrupted by one or more -O-, -S-, -N- groups;

[0020] Or R1 is C4-C 12 Heterocyclic aromatic group, C6-C 12 The heterocyclic aromatic group is a structure shown in chemical formula (II):

[0021]

[0022] is the substitution site;

[0023] X1 is -O-, -S-, -SO-, -SO2-;

[0024] In the R3, R4, and R5 of the chemical formula (II), two adjacent R groups can be forming a ring condensed with the five-membered aromatic heterocyclic ring containing X1;

[0025] or R3, R4, R5 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Alkoxyl groups;

[0026] Or R1 is C6-C 12 The aryl group is unsubstituted or substituted by one or more of a nitro group, a cyano group, a C1-C8 alkyl group, and a C1-C8 alkoxy group, wherein the hydrogen atoms on the C1-C8 alkyl group and the C1-C8 alkoxy group may be substituted by halogen.

[0027] In the above technical solution, R1 is especially a C1-C6 alkyl group, a monocyclic cycloalkyl group, a monocyclic aryl group, or a monocyclic heteroaryl group, which can optimize the photosensitivity performance of the photopolymerization initiator involved in the present invention.

[0028] Specific:

[0029] R2 is C1-C 12 Alkyl, which is unsubstituted or substituted with halogen, C3-C 12 Cycloalkyl, C3-C 12 Heterocycloalkyl, C3-C 12substituted with one of the heterocyclic aromatic groups, uninterrupted or interrupted by one or more -O- groups;

[0030] Or R2 is C1-C 12 Alkoxy, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-;

[0031] Or R2 is C3-C 12 Cycloalkyl, C3-C 12 The structure of the cycloalkyl group is chemical formula (III):

[0032]

[0033] n is 0-5;

[0034] m is 1-4;

[0035] Or R2 is C3-C 12 Heterocycloalkyl, which is unsubstituted or substituted by C1-C8 alkyl, and contains 1-2 -O-, -S-, -N-;

[0036] Or R2 is C6-C 20 Aryl, which is unsubstituted or substituted by C1-C8 alkyl, C3-C6 cycloalkyl, C3-C6 heterocycloalkyl, and the C1-C8 alkyl is interrupted by one or more O;

[0037] or R1 is a C6-C8 alkyl or C1-C8 alkoxy substituted by at least one O 12 The aromatic group.

[0038] Or R2 is a structure represented by chemical formula (II):

[0039]

[0040] is the substitution site;

[0041] X1 is -O-, -S-, -SO-, -SO2-;

[0042] In the R3, R4, and R5 of the chemical formula (II), two adjacent R groups can be forming a ring condensed with the five-membered aromatic heterocyclic ring containing X1;

[0043] or R3, R4, R5 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 of alkoxy.

[0044] In the above technical solution, when R2 is, in particular, a C1-C6 alkyl group, a phenyl group, or a six-membered cycloalkyl group, the free radical generation rate of the photopolymerization initiator of the present invention is optimal.

[0045] Preferably, in R1:

[0046] The monocyclic alkyl group is a five-membered ring or a six-membered ring;

[0047] The monoheterocycloalkyl group is a five-membered heterocyclic ring or a six-membered heterocyclic ring.

[0048] Specifically, the electron withdrawing group is cyano, nitro, C2-C 10 Alkylamine, C2-C 10 Alkoxy, C2-C 10 Alkylthio, C3-C 20 Heterocyclic group, C3-C 30 Heteroaryl, C6-C 20 An aromatic group or a group of the formula -L2-C(R6)=NOOCR7;

[0049] C2-C 10 Alkylamine, C2-C 10 Alkoxy, C2-C 10 Alkylthio, C3-C 20 Heterocyclic group, C6-C 30 Heteroaryl, C6-C 20 The aryl group is linked to Het1 via the carbonyl group;

[0050] L2 is a single bond or a carbonyl group;

[0051] R6 and R7 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Alkoxy, C6-C 20 The aromatic group.

[0052] Specifically, Het1 is further represented by chemical formula (IV):

[0053]

[0054] X2 and X3 are independently selected from CH;

[0055] Or, X2 and X3 can be forming a ring fused to a sulfur-containing five-membered heterocyclic ring;

[0056] a is 1-2;

[0057] In the above technical scheme, when Het1 is especially a dibenzo five-membered heterocycle and a benzo five-membered heterocycle, since these groups have a larger conjugated system and stronger intramolecular electron transfer properties, the stability and photosensitivity of the photopolymerization initiator involved in the present invention are optimized.

[0058] Specifically, the structures of the electron-withdrawing groups are: -CN, -NO2,

[0059] b is 1-6;

[0060] d is 1-9;

[0061] The methylene group in the cycloalkyl group is not interrupted by one or more -O- groups.

[0062] In the above technical solution, C6-C 20 The aryl group is selected from the group consisting of phenyl, diphenyl, terphenyl, anthracenyl, and naphthyl;

[0063] Preferred C6-C 20 The aryl group is selected from: phenyl;

[0064] C3-C 12 The heterocycloalkyl group is selected from: three-membered, four-membered, five-membered, and six-membered heterocycloalkyl groups, and the molecule contains at least one O, S, or N;

[0065] Preferred C3-C 12 The heterocycloalkyl group is a three-membered, five-membered, or six-membered heterocycloalkyl group, and contains at least one O or N in the molecule;

[0066] C3-C 12 The cycloalkyl group is selected from: three-membered, four-membered, five-membered, six-membered cycloalkyl

[0067] Preferred are: cyclopropane, cyclopentane, cyclohexane;

[0068] C6-C 12 The heterocyclic aromatic group is selected from the group consisting of thiophene, furan, pyrrole, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, benzothiophene, benzofuran, benzopyrrole, benzimidazole, benzoxazole, benzothiazole, benzopyrazole, benzisoxazole, and benzisothiazole;

[0069] Preferred C6-C 12 The heterocyclic aromatic group is selected from the group consisting of thiophene, furan, oxazole, thiazole, benzothiophene, benzofuran, benzimidazole, and benzoxazole;

[0070] C1-C 12 The alkyl group is selected from: C1-C 12 Alkyl, C1-C 10alkyl, C1-C9 alkyl, C1-C8 alkyl, C1-C7 alkyl, C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl, C1-C2 alkyl, C1 alkyl;

[0071] Preferred are: methyl, ethyl, propyl, C4 alkyl, C6 alkyl, C8 alkyl;

[0072] C1-C 12 The alkoxy group is selected from: C1-C 12 Alkoxy, C1-C 10 alkoxy, C1-C9 alkoxy, C1-C8 alkoxy, C1-C7 alkoxy, C1-C6 alkoxy, C1-C5 alkoxy, C1-C4 alkoxy, C1-C3 alkoxy;

[0073] Preferred are: methoxy, ethoxy, propoxy, C4 alkoxy;

[0074] Halogen is selected from: fluorine, chlorine, bromine;

[0075] Preferred halogens are selected from: fluorine.

[0076] In the above technical solution, all "at least one" means: 1, 2, 3. More specifically, the photopolymerization initiator is selected from the following compounds:

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083] A photocurable composition of the present invention comprises:

[0084] (a) a polymerizable compound having an ethylenically unsaturated bond; and

[0085] (b) a photopolymerization initiator, comprising at least one photopolymerization initiator provided by the present invention. The content of the photopolymerization initiator in the photocurable composition is 0.01-10 wt %;

[0086] A photocurable composition further comprises an alkali-soluble resin.

[0087] The photocurable composition may or may not contain a colorant.

[0088] The invention also provides application of the photocurable composition for preparing display photoresist, semiconductor photoresist or ink.

[0089] In the photocurable composition of the present invention, the amount is not particularly limited. The amount of the photopolymerization initiator added is preferably 1-70wt%, more preferably 1-50wt%, and most preferably 5-30wt% relative to 100wt% of the above-mentioned polymerizable compound having an ethylenically unsaturated bond.

[0090] In particular, when the photocurable composition of the present invention is made into a (colored) alkali-developable photosensitive resin composition, the content of the above-mentioned alkali-developable compound having an ethylenically unsaturated bond is preferably 1-20wt% in the (colored) alkali-developable photosensitive resin composition of the present invention, and particularly preferably 3-12wt%.

[0091] A solvent may be further added to the photocurable composition of the present invention. The solvent is usually one that can dissolve or disperse the above-mentioned components as required, and examples thereof include ketones such as methyl ethyl ketone, methyl amyl ketone, diethyl ketone, acetone, methyl isopropyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as ethyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane, and dipropylene glycol dimethyl ether; ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, and n-butyl acetate; cellosolve solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and propylene glycol methyl ether acetate; alcohol solvents such as methanol, ethanol, iso- or n-propanol, iso- or n-butanol, and amyl alcohol; ethylene glycol monomethyl acetate, ethylene glycol monomethyl acetate, and ethylene glycol monomethyl acetate. Ether ester solvents such as monoethyl acetate and propylene glycol methyl acetate; BTX solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as hexane, heptane, octane, and cyclohexane; terpene hydrocarbon oils such as turpentine, D-limonene, and pinene; paraffin solvents such as mineral spirits; halogenated aliphatic hydrocarbon solvents such as carbon tetrachloride, chloroform, trichloroethylene, dichloromethane, and 1,2-dichloroethane; halogenated aromatic hydrocarbon solvents such as chlorobenzene; carbitol solvents, aniline, triethylamine, pyridine, acetic acid, acetonitrile, carbon disulfide, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, water, etc. These solvents can be used alone or as a mixed solvent of two or more.

[0092] Among them, ketones and solvents, especially propylene glycol methyl ether acetate, cyclohexanone and the like are preferred because they improve the compatibility of the resist and the photopolymerization initiator in the photocurable composition.

[0093] The photocurable composition of the present invention may further contain an inorganic compound. Examples of the inorganic compound include metal oxides such as nickel oxide, iron oxide, iridium oxide, titanium oxide, zinc oxide, magnesium oxide, calcium oxide, potassium oxide, silicon dioxide, and aluminum oxide; layered clay minerals, Milori blue, calcium carbonate, magnesium carbonate, cobalt series, manganese series, glass powder, mica, talc, kaolin, ferrocyanide, various metal sulfates, sulfides, selenides, aluminum silicate, calcium silicate, aluminum hydroxide, platinum, gold, silver, and copper, among which titanium oxide, silicon dioxide, layered clay minerals, and silver are preferred. The content of the inorganic compound in the photocurable composition of the present invention is 100wt%, preferably 0.1-50wt%, and more preferably 0.5-20wt%, relative to the above-mentioned polymerizable compound having an ethylenically unsaturated bond. One or more of these inorganic compounds may be used.

[0094] The above-mentioned inorganic compound can be used as, for example, a filler, an antireflection agent, a conductive agent, a stabilizer, a flame retardant, a mechanical strength improving agent, a specific wavelength absorber, an ink repellent, and the like.

[0095] In addition, the photocurable composition of the present invention (particularly the alkali-developable photosensitive resin composition) may further contain a colorant to form a colored photocurable composition. Examples of the colorant include pigments, dyes, natural pigments, etc. These colorants may be used alone or in combination of two or more.

[0096] In the photocurable composition of the present invention, the amount of the colorant added is preferably 50 to 350 parts by mass, more preferably 100 to 250 parts by mass, based on 100 parts by mass of the polymerizable compound having an ethylenically unsaturated bond.

[0097] In addition, by using the above-mentioned polymerizable compound with ethylenically unsaturated bonds, using other organic polymers, the characteristic of cured product can also be improved. As this organic polymer, for example polystyrene, polymethyl methacrylate, methyl methacrylate-ethyl acrylate copolymer, poly (methyl) acrylic acid, styrene-(methyl) acrylic acid copolymer, (methyl) acrylic acid-methyl methacrylate copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl copolymer, polyvinyl chloride resin, ABS resin, nylon 6, nylon 66, nylon 12, polyurethane resin, polycarbonate polyvinyl butyral, cellulose ester, polyacrylamide, saturated polyester, phenolic resin, phenoxy resin, polyamide-imide resin, polyamic acid resin, epoxy resin etc. can be listed, wherein preferred polystyrene, (methyl) acrylic acid-methyl methacrylate copolymer, epoxy resin.

[0098] When other organic polymers are used, the amount thereof used is preferably 10 to 500 parts by mass based on 100 parts by mass of the above-mentioned polymerizable compound having an ethylenically unsaturated bond.

[0099] The photocurable composition of the present invention may further contain a monomer having an unsaturated bond, a chain transfer agent, a surfactant, and the like.

[0100] Examples of the monomer having an unsaturated bond include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobutyl acrylate, n-octyl acrylate, isooctyl acrylate, isononyl acrylate, stearyl acrylate, methoxyethyl acrylate, dimethylaminoethyl acrylate, zinc acrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, trimethylolpropane trimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, bisphenol A diglycidyl ether (meth)acrylate, bisphenol F diglycidyl ether (meth)acrylate, bisphenol Z diglycidyl ether (meth)acrylate, and tripropylene glycol di(meth)acrylate.

[0101] Examples of the chain transfer agent include mercaptoacetic acid, thiomalic acid, o-mercaptobenzoic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 3-mercaptobutyric acid, N-(2-mercaptopropionyl)glycine, 2-mercaptonicotinic acid, 3-[N-(2-mercaptoethyl)carbamoyl]propionic acid, 3-[N-(2-mercaptoethyl)amino]propionic acid, N-(3-mercaptopropionyl)alanine, 2-mercaptoethanesulfonic acid, 3-mercaptopropanesulfonic acid, 4-mercaptobutanesulfonic acid, dodecyl(4-methylthio)phenyl ether, 2-mercapto iodinated alkyl compounds such as iodoacetic acid, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptopropionate); and disulfides obtained by oxidation of the thiol compounds; and iodinated alkyl compounds such as iodoacetic acid, iodopropionic acid, 2-iodoethanol, 2-iodoethanesulfonic acid, and 3-iodopropanesulfonic acid.

[0102] As the above-mentioned surfactant, fluorine-containing surfactants such as perfluoroalkyl phosphates and perfluoroalkyl carboxylates, anionic surfactants such as higher fatty acid alkali salts, alkyl sulfonates, and alkyl sulfates; cationic surfactants such as higher amine halogenated acid salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycol alkyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, and fatty acid monoglycerides; amphoteric surfactants; surfactants such as silicone surfactants can be used, and they can also be used in combination.

[0103] Furthermore, in the photocurable composition of the present invention, in addition to the oxime ester compound of the present invention, other photopolymerization initiators or sensitizers may be used in combination as photopolymerization initiators as needed. Sometimes, the combined use of other photopolymerization initiators can produce significant synergistic effects, such as reducing the photocuring time and improving the sensitivity of the photocurable resin.

[0104] The photocurable composition involved in the present invention is suitable for protective film materials such as hard coating agents, antifouling films, antireflective films, impact buffer films, etc.; photocurable adhesives, adhesives, photodegradable coatings, coatings, and molded products; optical recording media such as holographic imaging materials; optical molding resins, for example, inks (resins) for 3D printing, photoresists for electronic circuits and semiconductor manufacturing, photoresists for electronic materials such as color filters, black matrices, and dry films in displays, etc.; interlayer insulating films, light extraction films, brightness enhancement films, and sealing materials; printing inks such as screen printing, offset printing, and gravure printing, and photocurable inks for inkjet printing; optical components such as lenses, lens arrays, optical waveguides, light guide plates, light diffusers, and diffraction elements; optical spacers, rib walls, and materials for nanoimprinting, etc.

[0105] More specifically, for example, the photocurable composition of the present invention can be used in color photoresist (RGB), black matrix (BM), photo-spacer, semiconductor photoresist, ink, etc.

[0106] The technical advantages of the photopolymerization initiator involved in the present invention are:

[0107] 1) The photopolymerization initiator of the present invention introduces a sulfone group. The oxygen atom in the sulfone has a lone pair of electrons, which can form p-π conjugation with the π orbital in the π electron system, resulting in delocalization of electrons in the entire molecule or molecular fragment, thereby reducing the intramolecular energy, increasing stability, and averaging the bond length of the molecule, that is, reducing the difference in the bond length of the conjugated double bond and the single bond, increasing the molar extinction coefficient, so that the photopolymerization initiator of the present invention is under the LED light source;

[0108] 2) The photopolymerization initiator of the present invention has high sensitivity to ultraviolet light of 350-400nm, is very sensitive to light, can be activated at lower energy or shorter illumination time, thereby initiating a polymerization reaction, and can make the photocuring process faster and more efficient, which helps to improve production efficiency and energy utilization efficiency;

[0109] 3) Due to the electron-withdrawing property of the sulfone group, the molecule is in a low electron density state, and low energy stimulation can make the photopolymerization initiator enter an excited state, thereby accelerating the reaction;

[0110] 4) The photopolymerization initiator involved in the present invention has a high sensitivity value in a black photoresist system, so that the photoresist using the photopolymerization initiator of the present invention can better block the background light and reduce the exposure of non-target areas. In the process of manufacturing complex integrated circuits, touch screen sensors, and high-end displays, the use of the photopolymerization initiator involved in the present invention can significantly improve the quality and reliability of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] Figure 1 It is the NMR image of Example 1 of the present invention. DETAILED DESCRIPTION

[0112] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0113] The reagents or instruments used in the present invention, if the manufacturer is not specified, are all conventional products that can be purchased from the market. For process parameters not specifically specified, conventional techniques can be used.

[0114] Example 1

[0115]

[0116] Step 1: Under nitrogen protection, add 2-nitrodibenzo[b,d]thiophene 5,5-dioxide (20g, 1.0eq) and acetyl chloride (7.81g, 1.2eq) to 200ml of dichloromethane, slowly add aluminum chloride (22.11g, 2eq) at 0°C, warm to room temperature, react at room temperature for 4-6h, after the reaction is complete, add 200ml of ice-water mixture, stir for 0.5h, add 2ml of concentrated hydrochloric acid, stir 0.5h, adjust the pH to 7 with a sodium bicarbonate solution prepared by 10g of sodium bicarbonate and 200g of water, shake, let stand, retain the organic phase, wash the aqueous phase three times with 50ml of dichloromethane, combine the organic phases, dry with 30g of anhydrous magnesium sulfate to remove water, and evaporate the dichloroethane. After evaporation, the crude product in the rotary evaporator is in the form of solid powder, pour it into 200ml of n-heptane, filter it with suction, and dry it in an oven at 75℃ for 2h to obtain 17.46g of the first intermediate compound.

[0117] Step 2: Under nitrogen protection, the product of step 1 (17.46g, 1eq) was dissolved in 200ml of dichloromethane, hydroxylamine hydrochloride (6.42g, 1.5eq) and sodium acetate (7.58g, 1.5eq) were added, stirred, heated to 60-70°C, reacted for 6-12h, and after the reaction was detected by TLC / HPLC, 1000ml of water was added and stirred, and the mixture was left to stand overnight, and then filtered to obtain a powdery solid, which was poured into 200ml of THF, and dried with 50g of anhydrous magnesium sulfate, and filtered, and the filtrate was evaporated by rotary evaporation to obtain an oily viscous substance in a rotary flask. The viscous substance was poured into 150ml of anhydrous methanol and stirred to precipitate, and filtered to obtain a powdery solid, which was dried at 70°C for 5h to obtain 15.76g of the second intermediate;

[0118] Step 3: In a 500ml three-necked flask, the product of step 2 (15.76g, 1.0eq) and acetyl chloride (4.98g, 1.2eq) were added to 200ml of dichloromethane, and triethylamine (8.02g, 1.5eq) was slowly added dropwise at 0°C, and the mixture was reacted at room temperature for 4-6 hours. After confirming that the reaction was complete, 500ml of water at 0°C was slowly added dropwise and stirred for 1 hour, and then the mixture was allowed to stand for stratification and the organic phase was retained; next, the pH of the organic phase was adjusted to neutral using 0.1mol / L dilute hydrochloric acid, and the organic phase was retained again after being washed once; then 30g of anhydrous magnesium sulfate was added to the organic phase for drying, and the solvent was removed by a rotary evaporator after filtering to obtain a viscous liquid with a purity greater than 93%; the viscous liquid was dissolved in 100ml of ethanol, and the ethanol solution was added dropwise to a large amount of water under high-speed stirring to precipitate a white solid product, which was filtered and dried to obtain the final product, and the product was 14.54g;

[0119] 1 H NMR-CDCl3: δ8.44-8.33(m,2H),8.31-8.23(m,2H),7.89(dd,1H),7.81(dd,1H),2.45(s,3H),2.20(s,3H).

[0120] Mass spectrometer MALDI-TOF-MS (m / z) = 360.0549;

[0121] Theoretical molecular weight: 360.0416.

[0122] The synthesis steps of Examples 2 to 8 are different from those of Example 1 in terms of the substrate in Step 1 and the acyl chloride in Step 3. Otherwise, the target compound of the above formula is prepared in substantially the same manner as in Synthesis Example 1 (same reaction molar ratio and reaction conditions). The specific example structures are shown in Table 1.

[0123] Table 1

[0124]

[0125]

[0126] Example 9

[0127]

[0128] Step 1: Under nitrogen protection, diphenylthiophene sulfone (20g, 1eq) and 2-methoxyacetyl chloride (11.82g, 1eq) were dissolved in 200ml of dichloromethane, AlCl3 (36.99g, 3.0eq) was slowly added at -20°C, the temperature was raised to room temperature, and the reaction was carried out for 4-6h. After the reaction was complete, the system temperature was lowered to -20°C, and 75ml of dichloromethane solution of 2-morpholineacetyl chloride (18.16g, 1.2eq) was slowly added dropwise. After the feeding was completed, the temperature was raised to room temperature, the reaction was carried out for 4-6h, and the 200 ml of ice-water mixture was stirred for 0.5 h, 2 ml of concentrated hydrochloric acid was added, and the mixture was stirred for 0.5 h. The pH value was adjusted to 7 with a sodium bicarbonate solution prepared by 10 g of sodium bicarbonate and 200 g of water, and the mixture was shaken and allowed to stand. The organic phase was retained, and the aqueous phase was washed three times with 50 ml of dichloromethane. The organic phases were combined, and dried with 30 g of anhydrous magnesium sulfate to remove water. The dichloroethane was evaporated off by rotary evaporation. After evaporation, the crude product in the rotary evaporator was in the form of solid powder. It was poured into 200 ml of n-heptane, filtered, and dried in an oven at 75 ° C for 2 h to obtain 32.63 g of the first intermediate compound.

[0129] Step 2: The product obtained in step 1 (32.63 g, 1.0 eq), isobutyl nitrite (12.21 g, 1.5 eq) and hydrochloric acid (4.00 g, 0.5 eq) were stirred, heated to 60-70°C, and reacted for 6-12 h. After the reaction was completed by TLC / HPLC, 1000 ml of water was added and stirred, and the mixture was allowed to stand overnight. The mixture was filtered to obtain a powdery solid, which was poured into 200 ml of dichloromethane, and dried with 50 g of anhydrous magnesium sulfate. The mixture was filtered and the filtrate was evaporated by rotary evaporation to obtain an oily viscous substance in a rotary flask. The viscous substance was poured into 150 ml of anhydrous methanol and stirred to precipitate. The mixture was filtered to obtain a powdery solid, which was dried at 70°C for 5 h to obtain 32.16 g of the second intermediate compound.

[0130] Step 3: The product of step 2 (32.16g, 1.0eq) and acetyl chloride (6.82g, 1.2eq) were added to 200ml of dichloromethane, and triethylamine (10.98g, 1.5eq) was slowly added dropwise at 0°C, and the mixture was reacted at room temperature for 4-6 hours. After confirming that the reaction was complete, 500ml of water at 0°C was slowly added dropwise and stirred for 1 hour, followed by standing for stratification and retaining the organic phase; next, the pH of the organic phase was adjusted to neutral using 0.1mol / L dilute hydrochloric acid, and the organic phase was retained again after being washed once; then 30g of anhydrous magnesium sulfate was added to the organic phase for drying, and the solvent was removed by a rotary evaporator after filtering to obtain a viscous liquid with a purity greater than 93%; the viscous liquid was dissolved in 100ml of ethanol, and the ethanol solution was added dropwise to a large amount of water under high-speed stirring to precipitate a white solid product, which was filtered and dried to obtain the final product, and the product was 30.54g.

[0131] 1 H NMR-CDCl3: δ8.62(dd,1H),8.52(d,1H),8.45-8.37(m,2H),8.19(dd,1H),8.07(dd,1H),5.00(s,2H),3.76-3.63(m,8H),3.36(s,3H),2.17(s,3H).

[0132] Mass spectrometer MALDI-TOF-MS (m / z) = 486.1111;

[0133] Theoretical molecular weight: 486.1097.

[0134] The synthesis steps of Example 10-Example 12 are different from those of Example 9 in terms of the substrate in step 1 and the acyl chloride in step 3. Otherwise, the target compound of the above formula is prepared in substantially the same manner as in Synthesis Example 9 (same reaction molar ratio and reaction conditions). The specific example structures are shown in Table 2.

[0135] Table 2

[0136]

[0137] Embodiment 13

[0138]

[0139] Step 1: Under nitrogen protection, diphenylthiophene sulfone (20g, 1eq) and propionyl chloride (18.82g, 2.2eq) were dissolved in 200ml of dichloromethane, AlCl3 (36.99g, 3.0eq) was slowly added at -20°C, the temperature was raised to room temperature, and the reaction was carried out for 4-6h. After the reaction was complete, 200ml of ice-water mixture was added, stirred for 0.5h, 2ml of concentrated hydrochloric acid was added, stirred for 0.5h, and the pH was adjusted to 7 with a sodium bicarbonate solution prepared by 10g of sodium bicarbonate and 200g of water, shaken, and kept. The organic phase was washed with 50ml of dichloromethane three times, the organic phases were combined, dried with 30g of anhydrous magnesium sulfate to remove water, and dichloroethane was evaporated. After evaporation, the crude product in the rotary evaporator was in the form of solid powder, poured into 200ml of n-heptane, filtered, and dried in an oven at 75°C for 2h to obtain 24.36g of the first intermediate compound.

[0140] Step 2: The product obtained in step 1 (24.36 g, 1.0 eq), isobutyl nitrite (22.95 g, 3 eq) and hydrochloric acid (15.03 g, 1 eq) were stirred, heated to 60-70°C, and reacted for 6-12 h. After the reaction was completed by TLC / HPLC, 1000 ml of water was added and stirred, and the mixture was allowed to stand overnight. The mixture was filtered to obtain a powdery solid, which was poured into 200 ml of dichloromethane, and dried with 50 g of anhydrous magnesium sulfate. The mixture was filtered and the filtrate was evaporated by rotary evaporation to obtain an oily viscous substance in a rotary flask. The viscous substance was poured into 150 ml of anhydrous methanol and stirred to precipitate. The mixture was filtered to obtain a powdery solid, which was dried at 70°C for 5 h to obtain 24.75 g of the second intermediate compound.

[0141] Step 3: The product of step 2 (24.75g, 1.0eq) and acetyl chloride (11.06g, 2.2eq) were added to 200ml of dichloromethane, and triethylamine (19.45g, 3eq) was slowly added dropwise at 0°C, and the mixture was reacted at room temperature for 4-6 hours. After confirming that the reaction was complete, 500ml of water at 0°C was slowly added dropwise and stirred for 1 hour, followed by standing for stratification and retaining the organic phase; next, the pH of the organic phase was adjusted to neutral using 0.1mol / L dilute hydrochloric acid, and the organic phase was retained again after being washed once; then 30g of anhydrous magnesium sulfate was added to the organic phase for drying, and the solvent was removed by a rotary evaporator after filtering to obtain a viscous liquid with a purity greater than 93%; the viscous liquid was dissolved in 100ml of ethanol, and the ethanol solution was added dropwise to a large amount of water under high-speed stirring to precipitate a white solid product, which was filtered and dried to obtain the final product, and the product was 22.62g.

[0142] 1 H NMR-CDCl3: δ8.57(d,2H),8.43(d,2H),8.21(dd,2H),2.44(s,6H),2.17(s,6H).

[0143] Mass spectrometer MALDI-TOF-MS (m / z) = 470.0782;

[0144] Theoretical molecular weight: 470.0784.

[0145] Embodiment 14

[0146]

[0147] Step 1: Under nitrogen protection, diphenylthiophene sulfone (20g, 1eq) and butyryl chloride (10.27g, 1.2eq) were dissolved in 200ml of dichloromethane, and AlCl3 (24.66g, 2eq) was slowly added at -20°C. After the feeding was completed, the temperature was raised to room temperature, and the reaction was carried out for 4-6h. 200ml of ice-water mixture was added, and the mixture was stirred for 0.5h. 2ml of concentrated hydrochloric acid was added, and the mixture was stirred for 0.5h. The pH was adjusted to 7 with a sodium bicarbonate solution prepared by 10g of sodium bicarbonate and 200g of water, and the mixture was shaken and allowed to stand. The organic phase was retained, and the aqueous phase was washed three times with 50ml of dichloromethane. The organic phases were combined, and the water was dried with 30g of anhydrous magnesium sulfate to remove water. The dichloroethane was evaporated off by rotary evaporation. After the evaporation was completed, the crude product in the rotary evaporation bottle was in the form of solid powder, which was poured into 200ml of n-heptane, filtered, and dried in an oven at 75°C for 2h to obtain 20.14g of the first intermediate compound;

[0148] Step 2: The product obtained in step 1 (20.14 g, 1.0 eq), isobutyl nitrite (9.91 g, 1.3 eq) and concentrated hydrochloric acid (7.49 g, 1.0 eq) were stirred, heated to 60-70°C, and reacted for 6-12 h. After the reaction was completed by TLC / HPLC, 1000 ml of water was added and stirred, and the mixture was left to stand overnight. The mixture was filtered to obtain a powdery solid, which was poured into 200 ml of THF, and dried with 50 g of anhydrous magnesium sulfate. The mixture was filtered and the filtrate was evaporated by rotary evaporation to obtain an oily viscous substance in a rotary flask. The viscous substance was poured into 150 ml of anhydrous methanol and stirred to precipitate. The mixture was filtered to obtain a powdery solid, which was dried at 70°C for 5 h to obtain 19.07 g of the second intermediate.

[0149] Step 3: The product of step 2 (19.07g, 1.0eq) and acetyl chloride (5.96g, 1.2eq) were added to 200ml of dichloromethane, and triethylamine (9.61g, 1.5eq) was slowly added dropwise at 0°C, and the mixture was reacted at room temperature for 4-6 hours. After confirming that the reaction was complete, 500ml of water at 0°C was slowly added dropwise and stirred for 1 hour, followed by standing for stratification and retaining the organic phase; next, the pH of the organic phase was adjusted to neutral using 0.1mol / L dilute hydrochloric acid, and the organic phase was retained again after being washed once; then 30g of anhydrous magnesium sulfate was added to the organic phase for drying, and the solvent was removed by a rotary evaporator after filtering to obtain a viscous liquid with a purity greater than 93%; the viscous liquid was dissolved in 100ml of ethanol, and the ethanol solution was added dropwise to a large amount of water under high-speed stirring to precipitate a white solid product, which was filtered and dried to obtain the final product, and the product was 18.42g.

[0150] 1 H NMR-CDCl3: δ8.51-8.47(m,1H),8.41-8.34(m,1H),8.20(dd,1H),8.01-7.94(m,1 H),7.89-7.82(m,1H),7.52(m,1H),7.38-7.30(m,1H),2.44(s,3H),2.17(s,3H).

[0151] Mass spectrometer MALDI-TOF-MS (m / z) = 343.0534;

[0152] Theoretical molecular weight: 343.0514.

[0153] The synthesis steps of Example 15-Example 16 are different from those of Example 14 in terms of the substrate in Step 1 and the acyl chloride in Step 3. Otherwise, the target compound of the above formula is prepared in substantially the same manner (same reaction molar ratio and reaction conditions) as in Synthesis Example 14. The specific example structures are shown in Table 3.

[0154] Table 3

[0155]

[0156] Embodiment 17

[0157]

[0158] Step 1: Under nitrogen protection, diphenylthiophene sulfone (20g, 1eq) and acetyl chloride (8.71g, 1.2eq) were dissolved in 200ml of dichloromethane, AlCl3 (36.99g, 3.0eq) was slowly added at -20°C, the temperature was raised to room temperature, and the reaction was carried out for 4-6h. After the reaction was complete, the system temperature was lowered to -20°C, valeryl chloride (13.38g, 1.2eq) was slowly added dropwise, the temperature was raised to room temperature, and the reaction was carried out for 4-6h. After the reaction was complete, 200ml of ice-water mixture was added. l, stirred for 0.5h, added 2ml of concentrated hydrochloric acid, stirred for 0.5h, adjusted the pH to 7 with a sodium bicarbonate solution prepared by 10g of sodium bicarbonate and 200g of water, oscillated, let stand, retain the organic phase, wash the aqueous phase with 50ml of dichloromethane three times, combine the organic phases, dry with 30g of anhydrous magnesium sulfate to remove water, and evaporate the dichloroethane. After evaporation, the crude product in the rotary evaporator is in the form of solid powder, poured into 200ml of n-heptane, filtered, and dried in an oven at 75°C for 2h to obtain 23.67g of the first intermediate compound.

[0159] Step 2: Under nitrogen protection, the product of step 1 (17.46g, 1eq) was dissolved in 200ml of dichloromethane, hydroxylamine hydrochloride (7.21g, 1.5eq) and sodium acetate (8.51g, 1.5eq) were added, stirred, heated to 60-70°C, reacted for 6-12h, and after the reaction was detected by TLC / HPLC, 1000ml of water was added and stirred, and the mixture was left to stand overnight, and then filtered to obtain a powdery solid, which was poured into 200ml of THF, and dried with 50g of anhydrous magnesium sulfate, and filtered, and the filtrate was evaporated by rotary evaporation to obtain an oily viscous substance in a rotary flask. The viscous substance was poured into 150ml of anhydrous methanol and stirred to precipitate, and filtered to obtain a powdery solid, which was dried at 70°C for 5h to obtain 20.17g of the second intermediate;

[0160] Step 3: In a 500ml three-necked flask, the product of step 2 (20.17g, 1.0eq) and acetyl chloride (5.32g, 1.2eq) were added to 200ml of dichloromethane, and triethylamine (11.42g, 1.5eq) was slowly added dropwise at 0°C, and the mixture was reacted at room temperature for 4-6 hours. After confirming that the reaction was complete, 500ml of water at 0°C was slowly added dropwise and stirred for 1 hour, and then the mixture was allowed to stand for stratification and the organic phase was retained; next, the pH of the organic phase was adjusted to neutral using 0.1mol / L dilute hydrochloric acid, and the organic phase was retained again after being washed once; then 30g of anhydrous magnesium sulfate was added to the organic phase for drying, and the solvent was removed by a rotary evaporator after filtering to obtain a viscous liquid with a purity greater than 93%; the viscous liquid was dissolved in 100ml of ethanol, and the ethanol solution was added dropwise to a large amount of water under high-speed stirring to precipitate a white solid product, which was filtered and dried to obtain the final product, and the product was 16.29g;

[0161] 1H NMR-CDCl3: δ8.45(d,1H),8.40-8.33(m,1H),8.33-8.26(m,2H),8.05(dd,1H),7.81(d d,1H),3.00(t,2H),2.45(s,3H),2.20(s,3H),1.68(m,2H),1.34(m,2H),0.96(t,3H).

[0162] Mass spectrometer MALDI-TOF-MS (m / z) = 339.1257;

[0163] Theoretical molecular weight: 339.1140.

[0164] Performance Testing

[0165] The following physical property evaluations were performed on the compounds obtained in the above synthesis examples. In addition, for comparison, the physical property evaluations were also performed on the photopolymerization initiators of the following Comparative Examples 1 to 5. The results are shown in Table 4.

[0166] (Comparative Example 1) (Comparative Example 2 (Comparative Example 3) (Comparative Example 4) (Comparative Example 5)

[0167] 1. Maximum absorption wavelength and molar absorption coefficient

[0168] The photoinitiator of the present invention is prepared as 10 -5 mol / L propylene glycol methyl ether acetate (PMA) solution, test its UV-visible absorption spectrum to obtain its maximum absorption wavelength (λ max ), and calculate the molar absorptivity (ε) at the maximum absorption wavelength according to Beer's law max ).

[0169] 2. Solubility

[0170] Taking propylene glycol methyl ether acetate (PMA), a reactive diluent widely used in the art, as an example, the maximum weight that can be dissolved in 100 g of solvent at 25° C. is used as the evaluation standard for the photoinitiator of the present invention.

[0171] 3. Light sensitivity

[0172] 20wt% of bisphenol fluorene resin, 60wt% of carbon black, 0.5wt% of the compound of the present invention as a photopolymerization initiator, 0.1wt% of FC-430 (3M leveling agent), and 19.4wt% of PMA were placed in a reaction mixing tank with a UV protective cover and a stirrer, and stirred at room temperature to prepare a photopolymer composition. The photopolymer composition was spin-coated on a glass substrate and dried on a hot plate at 100°C for 1 minute, then exposed using a step mask and developed in a 0.04% KOH aqueous solution. The sensitivity was evaluated based on an exposure dose in which the thickness of the step mask pattern was maintained at 80% of the initial thickness, and the exposure dose in which the thickness of the pattern of comparative example 1 was maintained at 80% of the initial thickness was defined as 1. Other photoinitiators were evaluated. Under the same residual thickness, the exposure dose was small and the sensitivity was high.

[0173] Table 4

[0174]

[0175]

[0176] The oxygen in the sulfone or sulfoxide involved in the present invention can enhance the photosensitivity of the molecule, because the introduction of oxygen makes the molecular structure more rigid and reduces the phenomenon of fluorescence quenching during the charge transfer process within the molecule. For oxygen-functionalized molecules, an intra-plane intramolecular charge transfer (PICT) state is formed, and a high fluorescence excited state is generated; while for derivatives without oxygen, a twisted intramolecular charge transfer (TICT) state is formed after light excitation, resulting in a significant reduction in fluorescence. Therefore, the change from S to SO2 increases the photosensitivity by enhancing the light absorption capacity of the molecule and reducing the occurrence of the TICT state. Sulfone and sulfoxide can be used as free radical scavengers, which can react with the free radicals generated during the photoinitiation process, thereby reducing the formation of peroxy radicals between free radicals and oxygen, thereby overcoming oxygen inhibition.

[0177] The photocuring initiator of the present invention is more suitable for black photoresist, and can achieve precise control of material deposition compared with the prior art, so that the position of each pixel is more accurate and the boundary is clearer. Through high-precision patterning capabilities, a finer pixel pitch can be achieved, thereby improving the overall resolution of the display.

[0178] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A photopolymerization initiator, characterized in that A compound having the structure shown in chemical formula (I): R1 is C1-C 12 Substituted or unsubstituted alkyl, C1-C 12 Substituted or unsubstituted alkoxy, C3-C 12 Substituted or unsubstituted cycloalkyl, C3-C 12 Substituted or unsubstituted heterocycloalkyl, C3-C 12 Heterocyclic aromatic or C6-C 12 a substituted or unsubstituted aryl group; R2 is C1-C 12 Substituted or unsubstituted alkyl, C1-C 12 Substituted or unsubstituted alkoxy, C3-C 12 Cycloalkyl, C3-C 12 Substituted or unsubstituted heterocycloalkyl, C6-C 20 Substituted or unsubstituted aryl or C6-C 12 Heterocyclic aromatic groups; L1 is a single bond or a carbonyl group; Ar1 is hydrogen or an electron-withdrawing group; Het1 is a C3-C 20 Heteroaromatic groups.

2. The photopolymerization initiator according to claim 1, characterized in that: R1 is C1-C 12 Alkyl, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-, -CO-; Or R1 is C1-C 12 Alkoxy, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-, -CO-; Or R1 is C3-C 12 The monocyclic alkyl of formula (I) is connected to the C1-C5 alkyl group via a single bond or a C1-C5 alkyl group, the C1-C5 alkyl group is unsubstituted or substituted by halogen, or is uninterrupted or is interrupted by one or more -O- groups; Or R1 is C3-C 12 The monoheterocyclic alkyl group of the present invention is a monoheterocyclic alkyl group, the methylene group on the ring may be interrupted by one or more -O- groups, the monoheterocyclic alkyl group is connected to the chemical formula (I) via a single bond or a C1-C5 alkyl group, the C1-C5 alkyl group is unsubstituted or substituted by halogen, or is uninterrupted or interrupted by one or more -O-, -S-, -N- groups; Or R1 is C3-C 12 Heterocyclic aromatic group, C6-C 12 The heterocyclic aromatic group is a structure shown in chemical formula (II): is the substitution site; X1 is -O-, -S-, -SO-, -SO2-; In the R3, R4, and R5 of the chemical formula (II), two adjacent R groups can be forming a ring condensed with the five-membered aromatic heterocyclic ring containing X1; or R3, R4, R5 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Alkoxyl groups; Or R1 is C6-C 12 The aryl group is unsubstituted or substituted by one or more of a nitro group, a cyano group, a C1-C8 alkyl group, and a C1-C8 alkoxy group, wherein the hydrogen atoms on the C1-C8 alkyl group and the C1-C8 alkoxy group may be substituted by halogen or be interrupted by one or more -O- groups.

3. The photopolymerization initiator according to claim 1, characterized in that: R2 is C1-C 12 alkyl, which is unsubstituted or substituted by halogen, uninterrupted or interrupted by one or more -O-; Or R2 is C1-C 12 Alkoxy, which is unsubstituted or substituted by halogen, nitro, cyano, or is uninterrupted or interrupted by one or more -O-; Or R2 is C3-C 12 Monocyclic alkyl, C3-C 12 The structure of the monocyclic alkyl is chemical formula (III): n is 0-5; m is 1-4; Or R2 is C3-C 12 A monoheterocyclic alkyl group which is unsubstituted or substituted with a C1-C8 alkyl group and contains 1-2 -O-, -S-, or -N-; Or R2 is C6-C 20 Aryl, which is unsubstituted or substituted by one or more of nitro, cyano, C1-C8 alkyl, C1-C8 alkoxy, wherein the hydrogen atoms on the C1-C8 alkyl and C1-C8 alkoxy may be substituted by halogen or interrupted by one or more -O-; Or R2 is C4-C 12 Heterocyclic aromatic group, C6-C 12 The heterocyclic aromatic group is a structure shown in chemical formula (II): is the substitution site; X1 is -O-, -S-, -SO-, -SO2-; In the R3, R4, and R5 of the chemical formula (II), two adjacent R groups can be forming a ring condensed with the five-membered aromatic heterocyclic ring containing X1; or R3, R4, R5 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 of alkoxy.

4. The photopolymerization initiator according to claim 2 or 3, characterized in that In R1 and R2: The monocyclic alkyl group is a five-membered ring or a six-membered ring; The monoheterocycloalkyl group is a five-membered heterocyclic ring or a six-membered heterocyclic ring.

5. The photopolymerization initiator according to claim 1, characterized in that Electron withdrawing groups are cyano, nitro, C2-C 10 Alkylamine, C2-C 10 Alkoxy, C2-C 10 Alkylthio, C3-C 20 Heterocyclic group, C3-C 30 Heteroaryl, C6-C 20 An aryl group or a group of the formula -L2-C(R6)=NOOCR7; C2-C 10 Alkylamine, C2-C 10 Alkoxy, C2-C 10 Alkylthio, C3-C 20 Heterocyclic group, C3-C 30 Heteroaryl, C6-C 20 The aryl group is linked to Het1 via the carbonyl group; L2 is a single bond or a carbonyl group; R6 has the same definition as R1, and R7 has the same definition as R2.

6. The photopolymerization initiator according to claim 1, characterized in that Het1 is further represented by chemical formula (IV): X2 and X3 are independently selected from CH; Or, X2 and X3 can be forming a ring fused to a sulfur-containing five-membered heterocyclic ring; a is 1-2.

7. The photopolymerization initiator according to claim 1, characterized in that The structures of electron-withdrawing groups are: -CN, -NO2, b is 1-6; d is 1-9; The methylene group in the cycloalkyl group is not interrupted by one or more -O- groups.

8. The photopolymerization initiator according to claim 1, characterized in that Specifically selected from the following compounds:

9. A photocurable composition, characterized in that: include: (a) a polymerizable compound having an ethylenically unsaturated bond; as well as (b) a photopolymerization initiator, comprising the photopolymerization initiator according to any one of claims 1 to 8, wherein the content of the photopolymerization initiator in the photocurable composition is 0.01 to 10 wt %; The photocurable composition may or may not contain a colorant.

10. A use of the photocurable composition according to any one of claims 1 to 8, characterized in that: Used to prepare display photoresist, semiconductor photoresist or ink.

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