Long wavelength photoinitiator, method of preparation and use thereof

Abstract

This invention provides a novel cationic sulfonium salt photoinitiator, its preparation method, and its application. This type of photoinitiator has the structure shown in formula (I). The sulfonium salt photoinitiator provided by this invention can be used for curing long-wavelength UV-LED light sources, exhibiting low migration and good absorption for long-wavelength light sources, thus solving the problem of adapting existing photoinitiators to long-wavelength UV-LED light sources.

Description

Technical Field

[0001] This invention relates to the field of photocurable materials technology, and more specifically, to a long-wavelength sulfonium salt photoinitiator, its preparation method, and its application. Background Technology

[0002] While there is increasing attention being paid to cationic photoinitiators, the variety of cationic photoinitiators remains limited. Furthermore, commonly used thioonium salt photoinitiators decompose during curing, releasing aromatic sulfides and toxic byproducts. Aromatic sulfides, such as phenyl sulfides, have an unpleasant odor, and toxic byproducts such as benzene and toluene are harmful to human health. Commonly used iodonium salts also decompose to produce volatile substances such as benzene, toluene, or isobutylbenzene, which are also harmful to human health. This severely limits the application of cationic initiators; for example, these cationic initiators cannot be used in printing inks on food or food-contact packaging, or in packaging that comes into direct contact with consumers.

[0003] As the irradiation light source in the field of photocuring materials technology, medium-pressure and high-pressure mercury lamps are most commonly used. However, due to their short lifespan, high heat generation, high energy consumption, environmental risks from the presence of mercury, and large equipment size, UV-LED lamps have been gaining popularity in recent years due to their energy-saving and long lifespan advantages. Among them, 405nm, 385nm, and 365nm are commonly used UV-LED light sources and exhibit good luminous intensity. Therefore, the purpose of this invention is to expand the types of cationic long-wavelength photoinitiators used in UV-LED light source formulation systems to solve the existing photoinitiator migration problems and long-wavelength LED light source adaptation problems, and to provide a long-wavelength thionium salt photoinitiator with better curing effect and environmental friendliness. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide sulfonium salt photoinitiators, their preparation methods, and applications. By designing the structure of the sulfonium salt photoinitiator, the prepared sulfonium salt photoinitiator exhibits high absorption for long-wavelength light sources, solving the problems of photoinitiator migration and LED long-wavelength light source adaptation in existing technologies.

[0005] To achieve the above objectives, the invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a sulfonium salt photoinitiator having the structure shown in the following general formula (I):

[0007]

[0008] in,

[0009] X and Y are independent representations of single bonds, alkylene groups, NR8, and CR9R. 10 Carbonyl group.

[0010] R1, R2, R3, R4, R5, R6, and R7 represent hydrogen, halogen, nitro, sulfonic acid, amino, cyano, C1-C10 alkyl, or C1-C10 alkoxy, and when X or Y is NR8, at least one of R1, R2, R3, R4, R5, R6, and R7 is a nitro group.

[0011] R8 represents a straight-chain or branched alkyl group of C1 to C10, a substituent formed by a straight-chain or branched alkyl group of C2 to C10 being interrupted by at least one -O-, -S-, -O-CO- or -CO-O-, a straight-chain or branched alkenyl group of C2 to C10, a straight-chain or branched alkynyl group of C2 to C10, an alkyl-substituted aryl group of C1 to C6, and an alkyl-substituted cycloalkyl group of C3 to C6 of C1 to C10.

[0012] R9, R 10 Independently representing hydrogen, nitro, cyano, C1-C10 straight-chain or branched alkyl, C1-C10 alkoxy, C2-C10 straight-chain or branched alkenyl, C2-C10 straight-chain or branched alkynyl, C1-C6 alkyl-substituted aryl, C1-C6 alkyl-substituted C3-C6 cycloalkyl, or R9, R 10 They are connected to form a ring;

[0013] A - It indicates inorganic anions or organic anions.

[0014] In this invention, by designing the structure of the thioonium salt photoinitiator, the prepared thioonium salt photoinitiator has low migration, solving the problem of existing photoinitiators releasing toxic and unpleasant photolysis products.

[0015] In this invention, the thioonium salt photoinitiator with general formula I contains macromolecular core groups such as carbazole or thioxanthone. During photocuring, the ultraviolet absorption exhibits a blue shift, which can better adapt to novel long-wavelength LED light sources.

[0016] In this invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10. C1-C5 can be C1, C2, C3, C4, C5. C1-C3 can be C1, C2, C3. C2-C10 can be C2, C3, C4, C5, C6, C7, C8, C9, C10. C1-C6 can be C1, C2, C3, C4, C5, C6. C3-C3 can be C3, C4, C5.

[0017] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0018] As a preferred embodiment of the present invention, R1, R2, R3, R4, R5, R6, and R7 are independently represented as hydrogen, halogen, nitro, cyano, C1-C5 alkyl, or C1-C5 alkoxy, and at least one of R1, R2, R3, R4, R5, R6, and R7 is a nitro group.

[0019] R8 represents a straight-chain or branched alkyl group of C1 to C6, a substituent formed by a straight-chain or branched alkyl group of C2 to C6 being interrupted by at least one -O-, -S-, -O-CO- or -CO-O-, a straight-chain or branched alkenyl group of C2 to C6, a straight-chain or branched alkynyl group of C2 to C6, an aryl group substituted with an alkyl group of C1 to C3, and a cycloalkyl group of C3 to C6 substituted with an alkyl group of C1 to C3.

[0020] R9, R 10 Independently representing hydrogen, nitro, cyano, C1-C6 straight-chain or branched alkyl, C1-C6 alkoxy, C2-C6 straight-chain or branched alkenyl, C2-C6 straight-chain or branched alkynyl, C1-C3 alkyl-substituted aryl, C1-C3 alkyl-substituted C3-C6 cycloalkyl, or R9, R 10 They are connected to each other to form a ring.

[0021] Preferably, when R9, R 10 When they are connected to form a ring, R9 and R 10 Interconnected to form

[0022] As a preferred technical solution of the present invention, A - F represents - Cl - ClO4 - CN - HSO4 - CF3COO, (SbF6) - (AsF6) - (BF4) - (PF6) - Al[OC(CF3)3]4 - , sulfonate ion, B(C6F5)4 - Or [(Rf)] b PF 6-b ] - any one of them;

[0023] Rf represents C1-C6 fluoroalkyl, b represents an integer from 1 to 5, and when b represents an integer from 2 to 5, the Rf groups may be the same or different.

[0024] Preferably, A- is selected from ClO4. - CN - HSO4 - CF3COO - (PF6) - (SbF6) - (AsF6) - (BF4) - B(C6F5)4 - Any one of them.

[0025] As a preferred embodiment of the present invention, the thionium salt photoinitiator is selected from any one of the following structures:

[0026]

[0027]

[0028] In a second aspect, the present invention provides a method for preparing a sulfonium salt photoinitiator as described in the first aspect, characterized in that the preparation method comprises the following steps:

[0029] (1) Friedel-Crafts reaction: Compound 1 and compound 2 undergo a Friedel-Crafts reaction in the presence of a catalyst to give onium salt intermediate 3.

[0030] (2) Nitration reaction: Onion salt intermediate 3 undergoes nitration reaction with nitric acid to obtain compound 4.

[0031] (3) Anion exchange reaction: Compound 4 undergoes anion exchange to obtain the target product.

[0032] Among them, compound 1 is

[0033] Compound 2 is

[0034] The preparation process of the sulfonium salt photoinitiator is as follows:

[0035]

[0036] Among them, X, Y, R1, R2, R3, R4, R5, R6, and R7 have the same protection scope as the first aspect.

[0037] It should be noted that both compound 1 and compound 2 used in this invention can be commercially available or prepared by known synthetic methods.

[0038] As a preferred embodiment of the present invention, the catalyst is selected from any one or a combination of at least two of aluminum trichloride, concentrated sulfuric acid, acetic anhydride, trifluoromethanesulfonic anhydride, and phosphorus pentoxide.

[0039] Preferably, in the Friedel-Crafts reaction, the molar ratio of compound 1 to compound 2 is 0.5:1 to 2:1, for example: 0.5:1, 1:1, 1.5:1, 2:1.

[0040] Preferably, the Friedel-Crafts reaction is carried out in an organic solvent selected from any one or a combination of at least two of dichloromethane, dichloroethane, benzene, and chlorobenzene.

[0041] Preferably, the Friedel-Crafts reaction is carried out at a system temperature of 0–50°C, such as 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C; and the reaction time is carried out at a system temperature of 2–24 h, such as 2 h, 6 h, 10 h, 14 h, 18 h, 22 h, or 24 h.

[0042] Preferably, the nitration reaction takes 1 to 40 hours and is carried out at a temperature of 30 to 50°C.

[0043] Preferably, in the nitration reaction, the molar ratio of onium salt intermediate 3 to nitric acid is 1:1 to 1:8, for example: 1:1, 1:2, 1:4, 1:6, 1:8.

[0044] Preferably, the nitration reaction is carried out in an organic solvent, which is selected from any one or a combination of at least two of dichloromethane, carbon tetrachloride, acetic acid, sulfuric acid, etc.

[0045] Preferably, in the anion exchange reaction, the molar ratio of compound 4 to organic salt / inorganic salt is 1:0.1 to 1:2, for example: 1:0.1, 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2.

[0046] Preferably, the organic or inorganic salt is selected from any one of potassium hexafluorophosphate, potassium fluoroborate, potassium hexafluoroantimonate, sodium tetra(pentafluorophenyl)borate, sodium hexafluoroantimonate, and sodium hexafluoroarsenate.

[0047] Preferably, the temperature of the anion exchange reaction is 0 to 40°C, for example, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, or 40°C.

[0048] Preferably, the anion exchange reaction time is 0.5 to 5 hours, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 1 hour.

[0049] Preferably, the anion exchange reaction further includes a post-processing step.

[0050] Preferably, the post-treatment method includes activated carbon adsorption, water washing, and crystallization.

[0051] Thirdly, the present invention provides an application of the thioonium salt photoinitiator as described in the first aspect, wherein the thioonium salt photoinitiator is used to prepare coatings, inks or adhesives, protective films for electronic components, interlayer insulating materials, pattern transfer materials or 3D printing materials, etc.

[0052] Fourthly, the present invention provides a photocurable composition comprising a thionium salt photoinitiator as described in the first aspect.

[0053] Preferably, the photocurable composition comprises the following components: a compound containing an ethylene oxide group and / or a compound containing a vinyl ether group, an oxetane compound, and a thionium salt photoinitiator as described in the first aspect.

[0054] Preferably, the compound containing ethylene oxide groups is selected from alicyclic epoxy compounds, aromatic epoxy compounds, and chain alicyclic epoxy compounds. From the viewpoint of further improving the curing speed, the compound containing ethylene oxide groups is further preferably an alicyclic epoxy compound, and even more preferably a polyfunctional alicyclic epoxy compound having two or more alicyclic epoxy groups.

[0055] Preferably, the alicyclic epoxy compound is selected from any one or a combination of at least two of the following: 3,4-epoxycyclohexenemethyl-3,4-epoxycyclohexenoate, 3,4,3′,4′-diepoxydicyclohexane, 2,2-bis(3,4-epoxycyclohexyl)propane, 2,2-bis(3,4-epoxycyclohexyl)-1,3-hexafluoropropane, bis(3,4-epoxycyclohexyl)methane, 1-[1,1-bis(3,4-epoxycyclohexyl)]ethylbenzene, bis((3,4-epoxycyclohexyl)methyl)adipate or bis(3,4-epoxycyclohexylmethyl oxalate).

[0056] The aromatic epoxy compound is a compound having an aromatic ring and an epoxy group in its molecule.

[0057] Preferably, the aromatic epoxy compound is selected from any one or a combination of at least two of the aromatic ring conjugated systems of epoxy compounds having a bisphenol backbone, a fluorene backbone, a biphenyl backbone, a naphthalene ring, or an anthracene ring. To achieve faster curing rates and better substrate adhesion, the aromatic epoxy compound is further preferably an epoxy compound having a bisphenol backbone and / or a fluorene backbone.

[0058] Preferably, the aromatic epoxy compound is selected from any one or a combination of at least two of bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, and fluorene-based epoxy compounds, and more preferably a combination of bisphenol A type epoxy compounds and fluorene-based epoxy compounds.

[0059] Preferably, the bisphenol A type epoxy compound includes JER-828EL, JER-YL980, JER-827, and JER-828 manufactured by Mitsubishi Chemical Corporation of Japan.

[0060] Preferably, the fluorene-based epoxy compounds include OGSOL EG-200 and OGSOL EG-28 produced by OSAKAGAS CHEMICALS.

[0061] The chain-like aliphatic epoxy compounds include aliphatic glycidyl ether type epoxy resins.

[0062] Preferably, the aliphatic glycidyl ether type epoxy resin includes trimethylolpropane glycidyl ether and ethylene glycol diglycidyl ether.

[0063] Preferably, the compound containing a vinyl ether group is selected from any one or a combination of at least two of triethylene glycol divinyl ether, 1,4-cyclohexyldiethanol divinyl ether, 4-hydroxybutyl vinyl ether, glyceryl carbonate vinyl ether, and dodecyl vinyl ether.

[0064] Preferably, the oxetane compound is selected from any one or a combination of at least two of 3-hydroxymethyl-3-ethyloxetane, 3-benzyloxymethyl-3-ethyloxetane, 3-ethyl-3-[[(2-ethylhexyl)oxy]methyl]oxetane, 3,3'-[oxybismethylene]bis[3-ethyl]oxetane, and 3-ethyl-3-[(ethylene oxide-2-methoxy)methyl]oxetane.

[0065] Preferably, the photocurable composition further includes additives.

[0066] It should be noted that no special restrictions are placed on the types of additives in this invention. Commonly used additives in the art are applicable, including but not limited to: pigments, fillers, leveling agents, dispersants, curing agents, surfactants, defoamers, and storage enhancers.

[0067] Preferably, the photocurable composition comprises the following components in parts by weight: 10-60 parts of a compound containing an ethylene oxide group and / or a compound containing a vinyl ether group, 5-40 parts of an oxetane compound, 1-20 parts of a thionium salt photoinitiator as described in the first aspect, and 0-10 parts of an additive.

[0068] In this invention, the weight parts of the compound containing an ethylene oxide group and / or the compound containing a vinyl ether group can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts, etc.

[0069] The weight parts of the oxetane compound can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts or 40 parts.

[0070] The weight parts of the thioonium salt photoinitiator can be 1 part, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, or 20 parts, etc.

[0071] The weight parts of the adjuvant can be 0 parts, 0.1 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts, etc.

[0072] In this invention, there are no special limitations on the preparation method of the photocurable composition. Commonly used methods for preparing photocurable compositions in the art are applicable, including but not limited to: mixing and stirring the components in the photocurable composition to obtain the photocurable composition.

[0073] In this invention, the photocurable composition can be used to prepare a coating. As a method for applying the resin composition to a support, coating methods such as dip coating, spray coating, rod coating, roller coating, or spin coating can be used. Furthermore, the thickness of the coating film can be appropriately controlled by adjusting the coating method and the viscosity of the composition.

[0074] Preferably, the material of the substrate is selected from glass, plastic, ceramic or metal.

[0075] The thickness of the coating can be designed according to the application. The thickness of the coating after drying is preferably 1 to 200 μm (e.g., 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, or 200 μm, etc.). If the thickness is less than 1 μm, there is a tendency for insufficient mechanical strength; if it exceeds 200 μm, there is a tendency for insufficient sensitivity due to reduced light transmittance, resulting in reduced photocurability of the mixed photocurable composition.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] This invention designs the structure of a thiamonium salt photoinitiator to prepare a thiamonium salt photoinitiator that is compatible with UV LED light sources for curing. It exhibits superior UV absorption at 405nm, 385nm, and 365nm, solving the migration problem and long-wavelength LED light source compatibility issue of existing photoinitiators. Furthermore, this thiamonium salt photoinitiator has low migration; migration tests show that the content of thiamonium salt photoinitiator precipitation is <0.0080%, specifically 0.0033% to 0.0080%. Detailed Implementation

[0078] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0079] Example 1

[0080] This embodiment provides a thionium salt photoinitiator and its preparation method, the preparation method being as follows:

[0081]

[0082] (1) Friedel-Crafts reaction: 12.6 g of isooctylcarbazole and 100 g of dichloromethane were added to a flask and cooled to 0-5 °C. 60 g of methanesulfonic acid and 5.1 g of phosphorus pentoxide were then added. 6.06 g of diphenyl sulfoxide was added, and the temperature was controlled at around 5 °C. After the addition was complete, the temperature was slowly raised to 35 °C. After 22 hours of reaction, the diphenyl sulfoxide was found to have largely reacted, with a product content of approximately 55%. The solution was quenched in ice water, and the organic layer was washed five times with pure water. The dichloromethane solution was concentrated to obtain a dark, viscous liquid. The organic matter was removed by toluene extraction, and the oil layer was separated. Toluene was added again for washing three times to obtain 6.4 g of a dark oily substance with a purity of 97.86%. The yield was 34.8%.

[0083] (2) Nitration reaction: Take 1.3g of onium salt intermediate, dissolve it in 50g of dichloromethane, stir until dissolved, cool to 8-10℃, and then slowly add 1.01g of fuming nitric acid. After 28h, the reaction is completed. Add water to wash until weakly acidic to neutral, with a purity of 98.18%. Dissolve the product in dichloromethane and proceed directly to the next step of the reaction.

[0084] (3) Anion exchange: The dichloromethane solution after nitration in the previous step was added to water, and 1.68 g of sodium hexafluoroantimonate was added for an anion exchange reaction at room temperature for 1 h. After activated carbon adsorption and stirring for 30 min, the mixture was filtered, washed with water, and the dichloromethane was concentrated to obtain 0.8 g of a yellow solid with a purity of 99.12%, namely the sulfonium salt photoinitiator P-1. The sulfonium salt photoinitiator P-1 provided in this example was characterized by NMR spectroscopy: 1H... NMR(500MHz,Chloroform-d)δ8.91(d,J=1.7Hz,1H),8.10(dd,J=7.5,1.5Hz,1H),7. 97-7.91(m,4H),7.85(d,J=7.5Hz,1H),7.80(dd,J=7.5,1.5Hz,1H),7.70(d,J=1.4H z,1H),7.57-7.50(m,5H),7.45-7.38(m,2H),4.20(dd,J=12.4,7.0Hz,1H),4.09-4. 01(m,1H),1.76(hept,J=7.0Hz,1H),1.49-1.28(m,8H),0.89(dt,J=9.3,7.9Hz,6H).

[0085] Examples 2-8

[0086] Following the reaction steps of Example 1, the raw materials were replaced sequentially and the reaction conditions were adjusted appropriately to obtain other corresponding thionium salt photoinitiators P-2, P-3, P-4, P-5, P-6, P-7, and P-8.

[0087] Table 1

[0088]

[0089]

[0090] Performance testing

[0091] Curing performance test

[0092] Taking the thioonium salt photoinitiator compound of the above embodiment as an example, the curing performance of the thioonium salt photoinitiator compound of the present invention was tested by combining it with compounds containing ethylene oxide groups and / or compounds containing vinyl ether groups and oxetane compounds.

[0093] The specific formulations of Examples 1-8 and Comparative Examples 1-2 are shown in Table 2 below.

[0094] Table 2

[0095]

[0096] in:

[0097] D-1: Photoinitiator D-2: Photoinitiator A1: 3,4-Epoxycyclohexenemethyl-3,4-Epoxycyclohexene ester;

[0098] A2: 3-Hydroxymethyl-3-ethyloxetane

[0099] A3: 1,4-Cyclohexyldiethanol divinyl ether

[0100] Additives: Leveling agent BYK307

[0101] The performance of the photocurable compositions provided in corresponding use cases 1-8 and comparative application example 1-2 was tested, and the specific test methods are as follows:

[0102] Curing performance evaluation: The resin compositions prepared according to the formulations in Application Examples 1-8 and Comparative Examples 1-2 were coated on glass plates and subjected to cascading exposure treatment using UV-LED lamps at three wavelengths of 365nm, 385nm, and 405nm. The curing condition was observed and evaluated using the touch method to test the application performance of the compositions.

[0103] The evaluation criteria are as follows: 1: Oily, not solid; 2: Oily surface, solidified bottom layer; 3: Sticky surface, heavy fingerprints after touch; 4: Basically dry, slightly rough to the touch, faint fingerprints; 5: Fully cured, smooth surface, no fingerprints after touch. The evaluation results are recorded in Table 3.

[0104] Migration evaluation: The photocurable compositions provided in Application Examples 1-8 and Comparative Examples 1-2 were stirred under a yellow light lamp, and the mixtures were rolled onto PET templates to form films. The films were then dried at 90°C for 5 minutes to form a coating film with a thickness of approximately 2 μm. The substrates with the coating were cooled to room temperature and exposed to a high-pressure mercury lamp (exposure machine model RW-UV70201, wavelength 200–500 nm, light intensity 100 mW / cm²). 2 The coating was exposed to irradiation for 5 seconds to obtain the desired cured films. Then, using 10 mL of methanol as a simulated solution, the cured films were placed in the simulated solution and left at room temperature for 24 hours. The amount of photoinitiator precipitated was analyzed by HPLC (Shimadzu LC-MS2020, mobile phase methanol / water = 55 / 45, 0.5% dihydrogen phosphate). The percentage content of the peak in the liquid phase was compared; the lower the relative initiator content in the liquid phase, the less likely it was to migrate. The evaluation results are recorded in Table 4.

[0105] Table 3

[0106]

[0107] Table 4

[0108] Migration Application Example 1 0.0075％ Application Example 2 0.0080％ Application Example 3 0.0063％ Application Example 4 0.0059％ Application Example 5 0.0033％ Application Example 6 0.0047％ Application Example 7 0.0069％ Application Example 8 0.0077％ Comparative Example 1 0.093％ Comparative Example 2 0.052％

[0109] As can be seen from the above description, the formulations containing the sulfonium salt photoinitiator P1-P8 of the present invention in Table 3 can be cured under UV-LED lamp irradiation in the 365nm, 385nm and 405nm wavelength bands, and the curing is particularly good at the 365nm wavelength.

[0110] The above embodiments of the present invention achieve the following technical effects: When using the sulfonium salt photoinitiator of the present invention as a raw material for photocurable compounds for curing, the curing effect is better compared with the use of conventional cationic photocurable initiators. That is, the sulfonium salt photoinitiator of the present invention has strong absorption in the long-wavelength ultraviolet band and is suitable for UV-LED light source curing systems.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sulfonium salt photoinitiator, characterized in that, It has the following general formula: in, X and Y are independent representations of single bonds, alkylene groups, NR8, and CR9R. 10 . R1, R2, R3, R4, R5, R6, and R7 represent hydrogen, halogen, nitro, sulfonic acid, amino, cyano, C1-C10 alkyl, or C1-C10 alkoxy, and when X or Y is NR8, at least one of R1, R2, R3, R4, R5, R6, and R7 is a nitro group. R8 represents a straight-chain or branched alkyl group of C1 to C10, a substituent formed by a straight-chain or branched alkyl group of C2 to C10 being interrupted by at least one -O-, -S-, -O-CO- or -CO-O-, a straight-chain or branched alkenyl group of C2 to C10, a straight-chain or branched alkynyl group of C2 to C10, an alkyl-substituted aryl group of C1 to C6, and an alkyl-substituted cycloalkyl group of C3 to C6. R9, R 10 Independently representing hydrogen, nitro, cyano, C1-C10 straight-chain or branched alkyl, C1-C10 alkoxy, C2-C10 straight-chain or branched alkenyl, C2-C10 straight-chain or branched alkynyl, C1-C6 alkyl-substituted aryl, C1-C6 alkyl-substituted C3-C6 cycloalkyl, or R9, R 10 They are connected to form a ring; A - It indicates inorganic anions or organic anions.

2. The sulfonium salt photoinitiator according to claim 1, characterized in that, When R9, R 10 When they are connected to form a ring, R9 and R 10 Interconnected to form 3. The sulfonium salt photoinitiator according to claim 2, characterized in that, R1, R2, R3, R4, R5, R6, and R7 are independently represented as hydrogen, halogen, nitro, cyano, C1-C5 alkyl, or C1-C5 alkoxy, and at least one of R1, R2, R3, R4, R5, R6, and R7 is a nitro group. R8 represents a straight-chain or branched alkyl group of C1 to C6, a substituent formed by a straight-chain or branched alkyl group of C2 to C6 being interrupted by at least one -O-, -S-, -O-CO- or -CO-O-, a straight-chain or branched alkenyl group of C2 to C6, a straight-chain or branched alkynyl group of C2 to C6, an aryl group substituted with a C1 to C3 alkyl group, and a cycloalkyl group of C3 to C6 substituted with a C1 to C3 alkyl group. R9, R 10 Independently representing hydrogen, nitro, cyano, C1-C6 straight-chain or branched alkyl, C1-C6 alkoxy, C2-C6 straight-chain or branched alkenyl, C2-C6 straight-chain or branched alkynyl, C1-C3 alkyl-substituted aryl, C1-C3 alkyl-substituted C3-C6 cycloalkyl, or R9, R 10 They are connected to each other to form a ring.

4. The sulfonium salt photoinitiator according to claim 1, characterized in that, The A - F represents - Cl - ClO4 - CN - HSO4 - CF3COO, (SbF6) - (AsF6) - (BF4) - (PF6) - Al[OC(CF3)3]4 - , sulfonate ion, B(C6F5)4 - Or [(Rf)] b PF 6-b ] - Any one of them; Rf represents C1-C6 fluoroalkyl, b represents an integer from 1 to 5, and when b represents an integer from 2 to 5, the Rf groups may be the same or different.

5. The sulfonium salt photoinitiator according to claim 4, wherein A- is selected from ClO4. - CN - HSO4 - CF3COO - (PF6) - (SbF6) - (AsF6) - (BF4) - B(C6F5)4 - Any one of them.

6. The sulfonium salt photoinitiator according to any one of claims 1-5, characterized in that, The thionium salt photoinitiator is selected from one or more of the following:

7. A method for preparing a sulfonium salt photoinitiator as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Friedel-Crafts reaction: Compound 1 and compound 2 undergo a Friedel-Crafts reaction in the presence of a catalyst to give onium salt intermediate 3. (2) Nitration reaction: Onion salt intermediate 3 undergoes nitration reaction with nitric acid to obtain compound 4. (3) Anion exchange reaction: Compound 4 undergoes anion exchange with organic / inorganic salts to obtain sulfonium salt photoinitiators; Among them, compound 1 is Compound 2 is The preparation process of the sulfonium salt photoinitiator is as follows: Among them, X, Y, R1, R2, R3, R4, R5, R6, and R7 have the same protection scope as the first aspect.

8. The preparation method according to claim 7, characterized in that, The catalyst is selected from any one or a combination of at least two of aluminum trichloride, concentrated sulfuric acid, acetic anhydride, trifluoromethanesulfonic anhydride, and phosphorus pentoxide; Preferably, in the Friedel-Crafts reaction, the molar ratio of compound 1 to compound 2 is 0.5:1 to 2:1; the Friedel-Crafts reaction is carried out in an organic solvent, which is selected from any one or a combination of at least two of dichloromethane, dichloroethane, benzene, and chlorobenzene. Preferably, the Friedel-Crafts reaction is carried out at a system temperature of 0–50°C. Preferably, the nitration reaction takes 1 to 40 hours, is carried out at a temperature of 30 to 50°C, and has a molar ratio of onium salt intermediate 3 to nitric acid of 1:1 to 1:

8. The reaction is carried out in an organic solvent, which is selected from any one or a combination of at least two of dichloromethane, carbon tetrachloride, acetic acid, and sulfuric acid. Preferably, in the anion exchange reaction, the molar ratio of compound 4 to organic salt / inorganic salt is 1:0.1 to 1:2, and the organic or inorganic salt is selected from any one of potassium hexafluorophosphate, potassium fluoroborate, potassium hexafluoroantimonate, sodium tetra(pentafluorophenyl)borate, sodium hexafluoroantimonate, and sodium hexafluoroarsenate. Preferably, the temperature of the anion exchange reaction is 0–40°C; and the reaction time is 0.5–5 h. Preferably, the anion exchange reaction further includes a post-processing step.

9. An application of the sulfonium salt photoinitiator as described in any one of claims 1-8, characterized in that, The thioonium salt photoinitiator is used to prepare coatings, inks or adhesives, protective films for electronic components, interlayer insulation materials, pattern transfer materials or 3D printing materials.

10. A photocurable composition, characterized in that, The photocurable composition comprises the sulfonium salt photoinitiator as described in any one of claims 1-6; Preferably, the photocurable composition comprises the following components: a compound containing an ethylene oxide group and / or a compound containing a vinyl ether group, an oxetane compound, and a thionium salt photoinitiator as described in any one of claims 1-6.

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