Aryl formyl oxime formate photoinitiator and preparation method thereof

Abstract

The invention relates to an oxime aryl formyl formate photoinitiator suitable for LED (light-emitting diode) photopolymerization, the photoinitiator has a structure as shown in a general formula (I), and Ar, R1 and R2 are defined in the specification and claims. The invention also relates to a preparation method of the photoinitiator and application of the photoinitiator in an LED photopolymerization system. # imgabs0 #

Description

Technical Field

[0001] The invention relates to an aromatic formyl formic acid oxime ester photoinitiator suitable for LED light curing, a preparation method thereof and application thereof in light curing using an LED light source. Background Art

[0002] Photocuring using LED light sources (also called LED photocuring or LED photopolymerization) has received increasing attention in the field of photosensitive polymers. Photoinitiators (also called LED photoinitiators) that match the wavelength of the LED light source are one of the important factors affecting the applicability of LED photocuring technology. So far, most of the LED photoinitiators that have been reported contain large conjugated structures (chromophores) in their structures. Although these large conjugated structures provide good light absorption capabilities for LED photoinitiators, they also bring color to the curing system because of the absorption of visible light. Darker colors will prevent light from passing through the curing system to reach the deep layers of the system, which undoubtedly limits the application of such LED photoinitiators in photocuring systems that require colorless and deep curing.

[0003] At present, the main way to solve the above problems is to develop LED photoinitiators with photobleaching properties. This type of photoinitiator can be cleaved at a specific wavelength, and the resulting fragments do not absorb in the visible light region, thereby obtaining a colorless cured product. However, one disadvantage of this type of photoinitiator is that it is difficult to completely cleave in the curing system, especially for systems that require deep curing, the color brought by the photoinitiator is difficult to completely disappear. Summary of the invention

[0004] The purpose of the present invention is to provide a photoinitiator which can effectively generate active free radicals that initiate polymerization and / or crosslinking reactions at the emission wavelength of commonly used LED light sources (e.g., 385 nm, 405 nm, 455 nm), but at the same time has no absorption or very low absorption of visible light.

[0005] The inventors of the present invention surprisingly found that the aforementioned purpose is achieved by an oxime ester compound having an α-dicarbonyl structure, which has a suitable weak absorption in the visible light region, and such a degree of absorption can lead to effective photolysis and generate active free radicals, but will not bring color to the curing system. In addition, some oxime ester compounds containing α-dicarbonyl structures have initiation properties even at high wavelengths (such as 455nm), achieving a wider range of applications. Further, the preparation of the oxime ester photoinitiator with an α-dicarbonyl structure of the present invention does not require precious metal catalysis and harsh conditions, and has excellent performance, and therefore has good application value.

[0006] In a first aspect, the present invention provides an aromatic formyl formate oxime ester compound having a structure shown in formula (I):

[0007]

[0008] in,

[0009] Ar is C6-C 10 -aryl or C6-C 10 -Aryl: halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups;

[0010] R1 and R2 are independently selected from hydrogen, Q, C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl, the aforementioned C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino group, wherein

[0011] R1 and R2 are not simultaneously any of hydrogen and Q,

[0012] Q is a coumarin group or a coumarin keto group having a structure represented by formula (II):

[0013]

[0014] wherein R3, R4, R5, R6 and R7 are independently selected from hydrogen, halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - aryl radical substitution,

[0015] n is 0 or 1, and

[0016] * indicates the position where the group Q is attached to other moieties.

[0017] In a second aspect, the present invention provides a method for preparing the aromatic formyl formic acid oxime ester compound represented by the aforementioned formula (I), the method comprising subjecting the aromatic formyl formic acid represented by the formula (III) to an oxime represented by the formula (IV) for an esterification reaction:

[0018]

[0019] Wherein, Ar in formula (III) and R1 and R2 in formula (IV) have the same meanings as Ar, R1 and R2 in formula (I), respectively.

[0020] In a third aspect, the present invention provides a composition for LED light curing, the composition comprising:

[0021] - at least one aromatic oxime ester compound represented by the aforementioned formula (I) as a photoinitiator, and

[0022] - a photocurable component selected from at least one of monomers, oligomers and prepolymers having ethylenically unsaturated functions,

[0023] Wherein, the mass ratio of the photoinitiator to the photocurable component is in the range of 0.2:100 to 6:100.

[0024] In a fourth aspect, the present invention provides the use of the aromatic formyl formic acid oxime ester compound represented by the aforementioned formula (I) as a photoinitiator in an LED photocuring system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The process of initiating polymerization using an aromatic formyl formic acid oxime ester compound as a photoinitiator according to the present invention is schematically shown;

[0026] Figure 2 The ultraviolet absorption spectra of benzoylformic acid acetone oxime ester (AOXE), p-fluorobenzoylformic acid acetone oxime ester (F-AOXE), p-chlorobenzoylformic acid acetone oxime ester (Cl-AOXE) and p-methoxybenzoylformic acid acetone oxime ester (O-AOXE) prepared according to Examples 1 to 4 in the range of 200nm to 450nm are shown, wherein the small figure in the upper right corner is a partial screenshot of the ultraviolet absorption spectrum in the range of 360nm to 440nm;

[0027] Figure 3 The UV absorption spectra of benzoylformic acid coumarin oxime ester (COXE), p-fluorobenzoylformic acid coumarin oxime ester (F-COXE), p-chlorobenzoylformic acid coumarin oxime ester (Cl-COXE) and p-methoxybenzoylformic acid coumarin oxime ester (O-COXE) prepared according to Examples 5 to 8 in the range of 200nm to 500nm are shown, wherein the small figure in the upper right corner is a partial screenshot of the UV absorption spectrum in the range of 430nm to 470nm;

[0028] Figure 4 The photopolymerization kinetics of AOXE, F-AOXE, Cl-AOXE and O-AOXE prepared according to Examples 1 to 4 and commercially available photoinitiator OXE-01 under a 385 nm LED light source to initiate polymerization of monomer tripropylene glycol diacrylate are shown;

[0029] Figure 5 The photopolymerization kinetics of AOXE, F-AOXE, Cl-AOXE and O-AOXE prepared according to Examples 1 to 4 and commercially available photoinitiator OXE-01 under a 405 nm LED light source to initiate polymerization of monomer tripropylene glycol diacrylate are shown;

[0030] Figure 6 The photopolymerization kinetics of tripropylene glycol diacrylate monomer initiated by COXE, F-COXE, Cl-COXE and O-COXE prepared according to Examples 5 to 8 and commercially available photoinitiator OXE-01 under a 405 nm LED light source are shown;

[0031] Figure 7 The photopolymerization kinetics of tripropylene glycol diacrylate initiated by COXE, F-COXE, Cl-COXE and O-COXE prepared according to Examples 5 to 8 and commercially available photoinitiator OXE-01 under a 455 nm LED light source are shown;

[0032] Figure 8 A comparison chart showing the deep polymerization of tripropylene glycol diacrylate initiated by F-AOXE prepared according to Example 2 and commercially available photoinitiator OXE-01 is shown. DETAILED DESCRIPTION

[0033] Herein, "halogen" refers to fluorine, chlorine, bromine and iodine. In the present invention, halogen is preferably fluorine, chlorine, bromine or a combination thereof, particularly preferably fluorine or chlorine.

[0034] In this document, the prefix “C n -C m -" in each case means that the defined group contains n to m carbon atoms, where n and m are the numbers specifically mentioned. For example, "C1-C 16 -" indicates that the defined group has 1 to 16 carbon atoms. In the case where the defined group has a substituent, the number of carbon atoms "C n -C m The "-" does not include the carbon atoms contained in the substituent.

[0035] In this article, “C1-C 16 "-alkyl" refers to a straight or branched chain alkyl group having 1 to 16 carbon atoms, such as C1-C 12 -alkyl, preferably C1-C8-alkyl, more preferably C1-C6-alkyl, and especially preferably C1-C4-alkyl. More specific examples include, but are not limited to, methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl and their isomers. “C1-C 16 "-alkyl" is preferably C1-C6-alkyl, more preferably C1-C4-alkyl, for example methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl.

[0036] In this article, “C6-C 10"-aryl" refers to a monocyclic or bicyclic aromatic hydrocarbon group containing 6 to 10 carbon atoms, such as phenyl, tolyl, ethylphenyl, propylphenyl, butylphenyl, xylyl, methylethylphenyl, diethylphenyl, methylpropylphenyl, naphthyl and isomers thereof. "C6-C 10 The "aryl" is preferably phenyl or naphthyl, more preferably phenyl.

[0037] In this article, “C3-C 10 "-Cycloalkyl" refers to a saturated alicyclic group having 3 to 10 carbon atoms, preferably having a monocyclic structure, such as C3-C6-cycloalkyl, more specifically cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and isomers thereof, etc.

[0038] In this article, “C3-C 10 -cycloalkyl-C1-C 16 -alkyl" means C3-C 10 -cycloalkyl substituted C1-C 16 -alkyl, wherein the alkyl group is connected to the rest of the compound through the alkyl structure. 10 -cycloalkyl" and "C1-C 16 -alkyl" have the meanings, preferred meanings and specific examples as described above. "C3-C 10 -cycloalkyl-C1-C 16 "-alkyl" is preferably C3-C6-cycloalkyl-C1-C4-alkyl, and more specific examples include, but are not limited to, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclopropylbutyl, cyclobutylmethyl, cyclobutylethyl, cyclobutylpropyl, cyclobutylbutyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylpropyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylpropyl, cyclohexylbutyl and isomers thereof.

[0039] In this article, “C1-C 16 -alkyl-C3-C 10 -cycloalkyl" means a C1-C 16 -alkyl-substituted-C3-C 10 -cycloalkyl, wherein the cycloalkyl structure is connected to the rest of the compound. 16 -alkyl" and "C3-C 10 -cycloalkyl" have the meanings, preferred meanings and specific examples as described above. "C1-C 16 -alkyl-C3-C 10"-cycloalkyl" is preferably C1-C4-alkyl-C3-C6-cycloalkyl, and more specific examples include, but are not limited to, methylcyclopropyl, ethylcyclopropyl, propylcyclopropyl, butylcyclopropyl, methylcyclobutyl, ethylcyclobutyl, propylcyclobutyl, butylcyclobutyl, methylcyclopentyl, ethylcyclopentyl, propylcyclopentyl, butylcyclopentyl, methylcyclohexyl, ethylcyclohexyl, propylcyclohexyl, butylcyclohexyl and isomers thereof.

[0040] In this article, “C1-C 16 -alkoxy" and "C1-C 16 -alkylthio" refers to C1-C 16 - A group in which the hydrogen on any carbon atom of an alkane chain is replaced by an oxygen (-O-) or sulfur (-S-) atom and is thus connected to the rest of the compound through the oxygen or sulfur atom. These two groups can also be represented by "C1-C 16 -alkyl-O-" and "C1-C 16 -alkyl-S-". Here "C1-C 16 "Alkyl" has the meaning, preferred meaning and specific examples as described above. "C1-C 16 "-alkoxy" is preferably C1-C6 alkoxy, such as methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, 2-butoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy and isomers thereof. "C1-C6 alkoxy" is preferably C1-C6 alkoxy, such as methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, 2-butoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy and isomers thereof. 16 "-alkylthio" is preferably C1-C6-alkylthio and can be methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, 2-butylthio, tert-butylthio, pentylthio, isopentylthio, hexylthio and isomers thereof, etc.

[0041] In this article, "single (C1-C 16 -alkyl)amino" refers to a C1-C 16 -alkyl substituted amino group. 16 -alkyl)amino" refers to amino groups with two C1-C 16 -alkyl-substituted amino groups, wherein the two C1-C 16 -alkyl substituents may be the same or different. 16 "-alkyl" has the meaning, preferred meaning and specific examples as described above.

[0042] In the following description of the present invention, unless otherwise expressly stated, the numerical values ​​in the present application can be regarded as being modified by the word "about". The inventors have reported the numerical values ​​in the examples as accurately as possible, although these numerical values ​​inevitably include certain errors.

[0043] In a first aspect, the present invention provides an aromatic formyl formate oxime ester compound having a structure shown in formula (I):

[0044]

[0045] in,

[0046] Ar is C6-C 10 -aryl or C6-C 10 -Aryl: halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups;

[0047] R1 and R2 are independently selected from hydrogen, Q, C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl, the aforementioned C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino group, wherein

[0048] R1 and R2 are not simultaneously any of hydrogen and Q,

[0049] Q is a coumarin group or a coumarin keto group having a structure represented by formula (II):

[0050]

[0051] wherein R3, R4, R5, R6 and R7 are independently selected from hydrogen, halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - aryl radical substitution,

[0052] n is 0 or 1, and

[0053] * indicates the position where the group Q is attached to other moieties.

[0054] In formula (1), Ar is, for example, phenyl or naphthyl which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, nitro, hydroxyl, mercapto, C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio, the aforementioned C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio is optionally substituted with at least one selected from halogen, hydroxy, mercapto, amino and C6-C 10 - Group substitution of aryl groups.

[0055] Ar is in particular phenyl or naphthyl which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, hydroxy, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one group selected from the group consisting of halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - Group substitution of aryl groups.

[0056] Ar is preferably phenyl or phenyl substituted by at least one, preferably one, group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, wherein the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio are optionally substituted by at least one group selected from halogen, hydroxyl and mercapto.

[0057] In some embodiments, Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxyl, sulfhydryl, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio. Preferably, Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxyl, sulfhydryl, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio in the para position.

[0058] For example, Ar is phenyl, p-fluorophenyl, p-chlorophenyl, p-methoxyphenyl or p-ethoxyphenyl.

[0059] In formula (1), R1 and R2 are independently selected from hydrogen, Q, C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl, the aforementioned C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 12 -alkoxy, C1-C 12 -alkylthio, mono(C1-C 12 -alkyl)amino and di(C1-C 12 -alkyl)amino group.

[0060] In any embodiment of the present invention, R1 and R2 are not simultaneously hydrogen and any one of the groups Q defined above and below. In other words, in any structure represented by formula (1), R1 and R2 are not simultaneously hydrogen and the groups Q, which will not be described in detail below.

[0061] In particular, R1 and R2 are independently selected from hydrogen, Q, C1-C8-alkyl or C1-C8-alkyl substituted by at least one group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkoxy and C1-C6-alkylthio.

[0062] In some embodiments, R1 is hydrogen or C1-C6-alkyl, and R2 is C1-C6-alkyl or Q. Preferably, R1 is C1-C4-alkyl, such as methyl or ethyl, and R2 is C1-C4-alkyl or Q, such as methyl or ethyl. It should be understood that when R1 and R2 are both C1-C6-alkyl or C1-C4-alkyl, they may be the same or different from each other.

[0063] The group Q is, for example, a coumarin group or a coumarin keto group having a structure represented by formula (II):

[0064]

[0065] in,

[0066] R3, R4, R5, R6 and R7 are independently selected from hydrogen, halogen, hydroxyl, mercapto, C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio, the aforementioned C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - aryl radical substitution, and

[0067] n is 0 or 1, preferably 0.

[0068] In any embodiment of the present invention, the group Q is a coumarin group or a coumarin keto group having a structure represented by formula (II):

[0069]

[0070] in,

[0071] R3, R5, R6 and R7 are hydrogen,

[0072] R4 is selected from halogen, hydroxyl, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and

[0073] n is 0.

[0074] In particular, in the group Q represented by the aforementioned formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkoxy or C1-C6-alkylthio, and n is 0.

[0075] More specifically, in the group Q represented by the aforementioned formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0. Preferably, in the group Q represented by the aforementioned formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from C1-C4-alkoxy or C1-C4-alkylthio, such as methoxy, ethoxy, and n is 0.

[0076] In an exemplary embodiment according to the first aspect of the present invention, the aromatic oxime formate compound has a structure represented by the following formula (I):

[0077]

[0078] in,

[0079] Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio,

[0080] R1 is hydrogen or C1-C6-alkyl,

[0081] R2 is a C1-C6-alkyl group or Q, wherein the group Q is a coumarin group having a structure shown in formula (II):

[0082]

[0083] in,

[0084] R3, R5, R6 and R7 are hydrogen,

[0085] R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, wherein the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and

[0086] n is 0.

[0087] According to the aforementioned exemplary embodiment, the aromatic oxime formate compound more preferably has a structure represented by the following formula (I):

[0088]

[0089] in,

[0090] Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio,

[0091] R1 is hydrogen or C1-C4-alkyl,

[0092] R2 is a C1-C4-alkyl group or Q, wherein the group Q is a coumarin group having a structure shown in formula (II):

[0093]

[0094] in,

[0095] R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxy, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

[0096] According to the aforementioned exemplary embodiment, the aromatic oxime formate compound more preferably has a structure represented by the following formula (I):

[0097]

[0098] in,

[0099] Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of fluorine, chlorine, C1-C4-alkoxy and C1-C4-alkylthio,

[0100] R1 is C1-C4-alkyl,

[0101] R2 is a C1-C4-alkyl group or Q, wherein the group Q is a coumarin group having a structure shown in formula (II):

[0102]

[0103] in,

[0104] R3, R5, R6 and R7 are hydrogen, R4 is selected from C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

[0105] According to the aforementioned exemplary embodiment, the aromatic formyl formic acid oxime ester compound particularly preferably has a structure represented by the following formula (I):

[0106]

[0107] in,

[0108] Ar is phenyl, p-fluorophenyl, p-chlorophenyl, p-methoxyphenyl or p-ethoxyphenyl,

[0109] R1 is methyl or ethyl,

[0110] R2 is methyl, ethyl or Q, wherein the group Q is a coumarin group having a structure shown in formula (II):

[0111]

[0112] in

[0113] R3, R5, R6 and R7 are hydrogen, R4 is selected from methoxy, ethoxy, methylthio or ethylthio, and n is 0.

[0114] More specifically, the present invention relates to an aromatic oxime formate compound having a structure represented by formula (I), wherein formula (I) is as described in any of the aforementioned embodiments, wherein R1 and R2 are not Q.

[0115] In addition, the present invention also relates to an aromatic oxime formate compound having a structure represented by formula (I), wherein formula (I) is as described in any of the aforementioned embodiments, and wherein R2 is Q.

[0116] In the compound of formula (I), the oxime ester group may exist in two configurations, i.e., (Z) type or (E) type. Isomers can be separated by conventional methods, but isomer mixtures can also be used as photoinitiators. Unless otherwise specified, the aromatic formyl formic acid oxime ester compound shown in formula (I) herein encompasses any of the aforementioned configurations and isomer mixtures of the two configurations.

[0117] In a second aspect, the present invention provides a method for preparing the aromatic formyl formic acid oxime ester compound represented by the aforementioned formula (I), the method comprising subjecting the aromatic formyl formic acid represented by the formula (III) to an oxime represented by the formula (IV) for an esterification reaction:

[0118]

[0119] Wherein, Ar in formula (III) and R1 and R2 in formula (IV) have the same meanings as Ar, R1 and R2 in formula (I), respectively.

[0120] The esterification reaction between the aromatic formylformic acid shown in formula (III) and the oxime shown in formula (IV) can be carried out in a manner known in the art. Through the esterification reaction, the carboxyl group in formula (III) and the hydroxyl group in formula (IV) are condensed to form an ester group, thereby obtaining a compound of formula (I). In the esterification reaction, the relative amount of the aromatic formylformic acid shown in formula (III) and the oxime shown in formula (IV) is not particularly limited, for example, the two are used in the following molar ratio: 1:1.5 to 1.5:1, preferably 1:1.2 to 1.2:1, for example 1:1.

[0121] The esterification reaction between the oxime shown in the arylformic acid shown in the formula (III) and the formula (IV) is usually carried out in the presence of a base. The base is, for example, an organic base, particularly a nitrogenous organic base. As non-limiting examples of the base, at least one selected from the group consisting of pyridine, alkyl-substituted pyridines such as 2-picoline, 3-picoline and 4-dimethylaminopyridine, dialkylamines such as diethylamine, and trialkylamines such as triethylamine can be mentioned.

[0122] Preferably, the base is selected from at least one of the group consisting of pyridine, 2-methylpyridine, 3-methylpyridine, 4-dimethylaminopyridine, diethylamine and triethylamine, more preferably selected from at least one of the group consisting of pyridine, 2-methylpyridine, 3-methylpyridine and 4-dimethylaminopyridine.

[0123] The base is usually used in a catalytic amount. Although the base can also be used in an equimolar amount, in excess or in a solvent amount, it is preferably used in a catalytic amount. The catalytic amount can be determined with reference to the examples given below, based on common knowledge in the art or by routine preliminary experiments. For example, the base and the aromatic formyl formic acid shown in formula (III) are used in the following molar ratio: 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2:1, more preferably 0.1:1.

[0124] The esterification reaction between the arylformic acid represented by formula (III) and the oxime represented by formula (IV) can be carried out under the operation of removing water. This can be carried out, for example, by distillation / condensation.

[0125] Preferably, the esterification reaction can be carried out under a dehydrating agent. The selection of the dehydrating agent is not particularly limited, and an organic dehydrating agent is preferably used. As non-limiting examples of the dehydrating agent, at least one selected from the group consisting of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide and 1,1'-carbonylbis-1H-imidazole can be mentioned.

[0126] The dehydrating agent can be used in a conventional amount, for example, in an amount equimolar to the reactant, preferably in an appropriate excess amount. For example, the dehydrating agent and the aromatic formylformic acid represented by formula (III) are used in the following molar ratio: 1.5:1 to 1:1, preferably 1.2:1 to 1:1, more preferably 1.2:1.

[0127] The esterification reaction between the aromatic formyl formic acid represented by formula (III) and the oxime represented by formula (IV) is usually carried out in a solvent, preferably in an organic solvent. The choice of solvent is not particularly limited, for example, at least one of tetrahydrofuran, benzene, toluene, ethyl acetate, N,N-dimethylformamide, dichloromethane and acetone can be used.

[0128] The esterification reaction can be carried out in a very wide temperature range. According to the present invention, it is advantageous that the esterification reaction is carried out at a temperature of -10°C to 150°C, preferably 0°C to 100°C, preferably at room temperature.

[0129] After the esterification reaction is completed, a product mixture containing the compound of formula (I) is obtained. The product mixture can be post-treated by any separation and purification means known in the art, for example, filtration, drying, distillation, recrystallization, chromatography, etc.

[0130] The reactants of the aforementioned esterification reaction, ie, the aromatic carboxylic acid represented by formula (III) and the oxime represented by formula (IV), can be synthesized by methods known in the art or obtained commercially without particular limitation.

[0131] In some embodiments of the method of the present invention, the aromatic formic acid represented by formula (III) is prepared, for example, by Friedel-Crafts acylation, comprising: subjecting the aromatic hydrocarbon Ar-H corresponding to the group Ar in formula (III) to Friedel-Crafts acylation with chloroformyl formate in the presence of a Lewis acid (such as aluminum chloride) to obtain aromatic formate, followed by hydrolysis to obtain the corresponding aromatic formic acid. The chloroformyl formate is used as an acylating agent, for example, methyl chloroformyl formate (i.e., monomethyl oxalyl chloride) or ethyl chloroformyl formate (i.e., monoethyl oxalyl chloride). The relative amounts of the aromatic hydrocarbon Ar-H and the chloroformyl formate are not particularly limited, for example, the two are used in the following molar ratio: 1:1.5 to 1.5:1, preferably 1:1.2 to 1.2:1, for example 1:1. The Lewis acid can be used in conventional amounts, for example, in an equimolar amount or an appropriate excess amount compared to the reactants. More specifically, the Lewis acid and methyl chloroformylformate are used in a molar ratio of 2.5:1 to 1:1, preferably 2:1 to 1.3:1, and more preferably 1.5:1.

[0132] The Friedel-Crafts acylation reaction can be carried out in a solvent known in the art without particular limitation. After the Friedel-Crafts acylation reaction, the arylformic acid of formula (III) is obtained by hydrolyzing the arylformic acid ester. The hydrolysis can be carried out in a manner known in the art, for example, by hydrolysis in the presence of a base to obtain the corresponding salt, and then acidifying to obtain the arylformic acid.

[0133] In some embodiments of the method of the present invention, the oxime represented by formula (IV) is prepared, for example, by an oximation reaction of a ketone or aldehyde represented by the following formula (V) with an oximation agent selected from hydroxylamine hydrochloride, hydroxylamine or a mixture thereof:

[0134]

[0135] wherein R1 and R2 have the same meanings as in formula (IV).

[0136] The oximation reaction is usually carried out in an organic solvent, preferably in an organic polar solvent. The solvent that can be used is, for example, ethanol or aqueous ethanol. In order to promote the oximation reaction to be complete, a salt or base such as sodium acetate, potassium acetate, pyridine, piperidine, triethylamine, etc. can be added. The oximation reaction can be carried out at room temperature or under heating. There is no particular limitation on the relative amount of the ketone and the oximation agent, for example, the two are used in the following molar ratio: 1:2.5 to 1:1.1, preferably 1:2 to 1:1.3, for example 1:1.5.

[0137] The aldehyde or ketone represented by formula (V) is commercially available or can be prepared according to a known conventional method.

[0138] The aromatic formyl formic acid oxime ester compound represented by formula (I) according to the present invention has appropriate weak absorption in the near-ultraviolet to visible light radiation range, for example, 350 to 470 nm, especially in the wavelength range of 365 to 460 nm, so that it can effectively photolyze to generate active free radicals that initiate polymerization and / or crosslinking, but will not bring color to the curing system. Therefore, it can be used as a photoinitiator in a photocuring system that requires colorlessness and a photocuring system that requires deep curing.

[0139] Without being bound by any theory, the inventors of the present invention speculate that the aromatic formyl formate oxime ester compound shown in formula (I) is irradiated with a common LED light source with an emission wavelength of 385nm, 405nm and 455nm to attach Figure 1 Specifically, Figure 1 As shown, under the irradiation of LED light source, the compound first undergoes nitrogen-oxygen bond cleavage at the oxime ester structure to generate one molecule of aromatic formyloxy free radical and one molecule of imine free radical, and then the benzoyl formyloxy free radical cleaves one molecule of carbon dioxide to generate one molecule of benzoyl free radical. This free radical acts as the leading active free radical to initiate polymerization reaction and / or cross-linking reaction in the curing system.

[0140] Therefore, in a third aspect, the present invention provides a composition for LED light curing, the composition comprising:

[0141] - at least one aromatic oxime ester compound represented by the aforementioned formula (I) as a photoinitiator, and

[0142] - a photocurable component selected from at least one of monomers, oligomers and prepolymers having ethylenically unsaturated functions,

[0143] Wherein, the mass ratio of the photoinitiator to the photocurable component is in the range of 0.2:100 to 6:100.

[0144] In some embodiments, the photoinitiator and the photocurable component are present in the composition for LED photocuring in a mass ratio ranging from 0.5:100 to 5:100, especially from 1:100 to 3:100.

[0145] The monomer having ethylenically unsaturated functions suitable for use as the photocurable component of the present invention is not particularly limited, and may be, for example, a monofunctional or polyfunctional ethylenically unsaturated compound.

[0146] Examples of suitable monofunctional ethylenically unsaturated compounds include, but are not limited to: (meth)acrylic acid and its salts; (meth)acrylates, for example, alkyl esters such as methyl, ethyl, 2-chloroethyl, N,N-dimethylaminoethyl, n-butyl, isobutyl, pentyl, hexyl esters, hydroxyalkyl esters such as 2-hydroxyethyl, 2-hydroxypropyl, 4-hydroxybutyl esters, epoxyalkyl esters such as glycidyl, 2,3-epoxybutyl, 3,4-epoxybutyl, 2,3-epoxycyclohexyl, 10,11-epoxyundecyl esters (meth)acrylamide, N-substituted (meth)acrylamide, for example N-methylol acrylamide, N-hydroxymethyl methacrylamide, N-ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-phenyl methacrylamide, N-benzyl acrylamide, N-benzyl methacrylamide, N-nitrophenyl a ... phenylmethacrylamide, N-ethyl-N-phenylacrylamide, N-ethyl-N-phenylmethacrylamide, N-(4-hydroxyphenyl)acrylamide and N-(4-hydroxyphenyl)methacrylamide; (meth)acrylonitrile; anhydrides and esters of unsaturated carboxylic acids other than (meth)acrylic acid, such as itaconic anhydride, maleic anhydride, 2,3-dimethylmaleic anhydride, 2-chloromaleic anhydride, maleic esters; styrene and substituted styrenes, such as methylstyrene, chloromethylstyrene and o-, m- and p-hydroxystyrene acetate vinyl ethers and vinyl halides, such as isobutyl vinyl ether, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, octyl vinyl ether and phenyl vinyl ether, vinyl chloride and vinylidene chloride; vinyl and allyl esters of carboxylic acids, such as vinyl acetate, vinyl acrylate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate, divinyl succinate, diallyl phthalate, triallyl phosphate.

[0147] Examples of suitable multifunctional ethylenically unsaturated compounds include, but are not limited to, di(meth)acrylates such as 1,6-hexanediol diacrylate (HDDA), ethylene glycol diacrylate, propylene glycol diacrylate, glycerol diacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, glycerol dimethacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), neopentyl glycol diacrylate, hexamethylene glycol diacrylate, bisphenol A diacrylate, dipentaerythritol diacrylate, pentaerythritol dimethacrylate, dipentaerythritol di ... tri(meth)acrylates, such as glycerol triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, glycerol trimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol triacrylate, sorbitol triacrylate; tetra(meth)acrylates, such as pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate; penta(meth)acrylates, such as dipentaerythritol pentaacrylate, dipentaerythritol tetramethacrylate.

[0148] The present invention also has no particular restrictions on prepolymers or oligomers with ethylenically unsaturated functions suitable for use as photocurable components, such as epoxy (meth) acrylic resins, polyurethane (meth) acrylic resins, polyester (meth) acrylic resins, polyether (meth) acrylic resins, and acrylated poly (meth) acrylic resins.

[0149] The composition for LED light curing of the present invention may also optionally contain an organic solvent. The selection of the organic solvent is conventional. As the organic solvent, aromatic hydrocarbons such as benzene and toluene, halogenated alkanes such as chloroform, methylene chloride, ethyl chloride, ketones such as acetone, butanone, pentanone, alcohols such as methanol, ethanol, propanol, isopropanol, ethylene glycol, and glycol ethers, glycol ether acetates, propylene glycol ethers, propylene glycol ether acetates, etc. may be mentioned.

[0150] The composition for LED light curing of the present invention may optionally further comprise other additives, such as a leveling agent, an antioxidant, an anti-settling agent, a colorant, a microbicide, such as an antibacterial agent, and a heat preservation material additive.

[0151] It should be understood that the composition for LED light curing of the present invention may be a mixture of components; the composition for LED light curing of the present invention may also be in the form of a component package, that is, one or more components are stored separately from one or more other components and are not formulated together to form a curing system until application.

[0152] In a fourth aspect, the present invention provides the use of the aromatic formyl formic acid oxime ester compound represented by the aforementioned formula (I) as a photoinitiator in an LED photocuring system.

[0153] In particular, the present invention provides the use of the aromatic formyl formic acid oxime ester compound represented by the aforementioned formula (I) in a LED light curing system requiring colorlessness and a LED light curing system requiring deep curing.

[0154] Specifically, the present invention includes but is not limited to the following technical solutions:

[0155] 1. An aromatic formyl formic acid oxime ester compound having a structure shown in formula (I):

[0156]

[0157] in,

[0158] Ar is C6-C 10 -aryl, or a C6-C 10 -Aryl: halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups;

[0159] R1 and R2 are independently selected from hydrogen, Q, C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl, the aforementioned C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C10 -cycloalkyl is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino group, wherein

[0160] R1 and R2 are not simultaneously any of hydrogen and Q,

[0161] Q is a coumarin group or a coumarin keto group having a structure represented by formula (II):

[0162]

[0163] wherein R3, R4, R5, R6 and R7 are independently selected from hydrogen, halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - aryl radical substitution,

[0164] n is 0 or 1, and

[0165] * indicates the position where the group Q is attached to other moieties.

[0166] 2. The aromatic formyl formate oxime ester compound according to technical solution 1, wherein in formula (I), Ar is a phenyl or naphthyl group which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, nitro, hydroxyl, thiol, C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio, the aforementioned C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio is optionally substituted with at least one selected from halogen, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups;

[0167] Preferably, Ar is phenyl or naphthyl which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one group selected from the group consisting of halogen, nitro, hydroxyl, mercapto, amino and C6-C 10 - radical substitution of aryl groups;

[0168] More preferably, Ar is phenyl or phenyl substituted by at least one, preferably one, group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio optionally being substituted by at least one group selected from halogen, hydroxyl and mercapto;

[0169] Most preferably, Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio, in particular, Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio.

[0170] 3. The aromatic formyl formate oxime ester compound according to technical solution 1 or 2, wherein in formula (I), R1 and R2 are independently selected from hydrogen, Q, C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl, the aforementioned C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 12 -alkoxy, C1-C 12 -alkylthio, mono(C1-C 12 -alkyl)amino and di(C1-C 12 -alkyl)amino group substitution;

[0171] Preferably, R1 and R2 are independently selected from hydrogen, Q, C1-C8-alkyl or C1-C8-alkyl substituted by at least one group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkoxy and C1-C6-alkylthio;

[0172] More preferably, R1 is hydrogen or C1-C6-alkyl, R2 is C1-C6-alkyl or Q; in particular, R1 is C1-C4-alkyl, such as methyl or ethyl, R2 is C1-C4-alkyl or Q, such as methyl or ethyl;

[0173] in

[0174] R1 and R2 are not simultaneously any of hydrogen and a group Q.

[0175] 4. The aromatic formyl formate oxime ester compound according to any one of the aforementioned technical solutions 1 to 3, wherein in formula (II), R3, R5, R6 and R7 are hydrogen,

[0176] R4 is selected from halogen, hydroxyl, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and

[0177] n is 0;

[0178] Preferably, in formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkoxy or C1-C6-alkylthio, and n is 0;

[0179] More preferably, in formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

[0180] 5. The aromatic formyl formate oxime ester compound according to any one of the aforementioned technical solutions 1 to 4, wherein in formula (I),

[0181] Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio,

[0182] R1 is hydrogen or C1-C6-alkyl,

[0183] R2 is a C1-C6-alkyl group or Q, wherein Q is a coumarin group having a structure shown in formula (II),

[0184] In formula (II),

[0185] R3, R5, R6 and R7 are hydrogen,

[0186] R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, wherein the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and

[0187] n is 0;

[0188] Preferably, in the aforementioned formula (I), Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio.

[0189] 6. The aromatic formyl formate oxime ester compound according to the aforementioned technical solution 5, wherein in formula (I),

[0190] Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio,

[0191] R1 is hydrogen or C1-C4-alkyl,

[0192] R2 is a C1-C4-alkyl group or Q, wherein the group Q is a coumarin group having a structure shown in formula (II),

[0193] In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

[0194] 7. The aromatic formyl formate oxime ester compound according to the aforementioned technical solution 6, wherein in formula (I),

[0195] Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of fluorine, chlorine, C1-C4-alkoxy and C1-C4-alkylthio,

[0196] R1 is C1-C4-alkyl,

[0197] R2 is a C1-C4-alkyl group or Q, wherein Q is a coumarin group having a structure shown in formula (II),

[0198] In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

[0199] 8. The aromatic formyl formate oxime ester compound according to the aforementioned technical solution 7, wherein in formula (I),

[0200] Ar is phenyl, p-fluorophenyl, p-chlorophenyl, p-methoxyphenyl or p-ethoxyphenyl,

[0201] R1 is methyl or ethyl,

[0202] R2 is methyl, ethyl or Q, wherein Q is a coumarin group having a structure shown in formula (II),

[0203] In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from methoxy, ethoxy, methylthio or ethylthio, and n is 0.

[0204] 9. The aromatic formylformic acid oxime ester compound according to any one of the aforementioned technical solutions 1-8, wherein R1 and R2 are not Q.

[0205] 10. The aromatic formylformic acid oxime ester compound according to any one of the aforementioned technical solutions 1-8, wherein R2 is Q.

[0206] 11. A method for preparing an aromatic formylformic acid oxime ester compound according to any one of technical solutions 1 to 10, the method comprising subjecting an aromatic formylformic acid represented by formula (III) to an oxime represented by formula (IV) for an esterification reaction:

[0207]

[0208] Wherein, Ar in formula (III) and R1 and R2 in formula (IV) have the same meanings as Ar, R1 and R2 in formula (I), respectively.

[0209] 12. A composition for LED light curing, comprising:

[0210] - at least one aromatic oxime ester compound according to any one of technical solutions 1 to 10 as a photoinitiator, and

[0211] - a photocurable component selected from at least one of monomers, oligomers and prepolymers having ethylenically unsaturated functions,

[0212] The mass ratio of the photoinitiator to the photocurable component is in the range of 0.2:100 to 6:100, preferably in the range of 0.5:100 to 5:100, and especially in the range of 1:100 to 3:100.

[0213] 13. A composition according to technical solution 12, wherein the monomer is selected from at least one of the following groups: monofunctional ethylenically unsaturated compounds, such as (meth)acrylic acid and its salts, (meth)acrylates, (meth)acrylamide, N-substituted (meth)acrylamide, (meth)acrylonitrile, anhydrides and esters of unsaturated carboxylic acids other than (meth)acrylic acid, styrene and substituted styrene, vinyl ethers and halogenated vinyls, vinyl and allyl esters of carboxylic acids; and multifunctional ethylenically unsaturated compounds, such as (meth)acrylic acid type monomers such as di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates and penta(meth)acrylates.

[0214] 14. A composition according to technical solution 12, wherein the prepolymer or oligomer is selected from at least one of the following groups: epoxy (meth) acrylic resin, polyurethane (meth) acrylic resin, polyester (meth) acrylic resin, polyether (meth) acrylic resin and acrylated poly (meth) acrylic resin.

[0215] 15. Use of the aromatic formyl formic acid oxime ester compound according to any one of technical solutions 1 to 10 as a photoinitiator in an LED photocuring system, especially in a colorless LED photocuring system and a deep-layer curing LED photocuring system.

[0216] 16. Use of the aromatic formyl formic acid oxime ester compound according to technical solution 9 in an LED light curing system requiring deep curing.

[0217] Example

[0218] The technical scheme of the present invention will be further described in detail below by way of example. It will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the examples, the techniques or conditions or product specifications described in the literature in the art are followed.

[0219] Example 1: Synthesis of a photoinitiator AOXE having the following structure

[0220]

[0221] Acetone (1.74 g, 30 mmol) and hydroxylamine hydrochloride (0.69 g, 10 mmol) were added to a 100 mL single-necked flask and reacted at room temperature for 5 h. Excess acetone was distilled off under reduced pressure to obtain acetone oxime.

[0222] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), benzoylformic acid (1.50 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to another 100 mL single-necked flask, and 30 mL of dichloromethane was added as solvent. Acetone oxime (0.73 g, 10 mmol) was dissolved in 10 mL of dichloromethane and slowly added dropwise to the single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. Then, the crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:6 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product AOXE.

[0223] The hydrogen spectrum data of AOXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.04–7.95 (m, 2H), 7.75–7.64 (m, 1H), 7.52 (dd, J = 8.5, 7.2 Hz, 2H), 2.05 (d, J = 3.9 Hz, 6H).

[0224] The carbon spectrum data of AOXE is: 13 C NMR (101 MHz, chloroform-d) δ 186.04, 166.27, 162.86, 135.06, 132.47, 129.87, 129.00, 21.82, 17.25.

[0225] Example 2: Synthesis of a photoinitiator F-AOXE having the following structure

[0226]

[0227] 2.1 Synthesis of p-fluorobenzoylformic acid

[0228] Add methyl oxalyl chloride (1.22g, 10mmol) and aluminum chloride (1.99g, 15mmol) to a 100mL single-mouth flask, and add 30mL of dichloromethane as a solvent. Use a dropping funnel to slowly drop fluorobenzene (0.96g, 10mmol) dissolved in 30mL of dichloromethane into the aforementioned single-mouth flask, and stir at 5°C until the addition is completed. After the addition is completed, react for 5h, and then remove the solvent by vacuum distillation to obtain methyl p-fluorobenzoylformate. Add 30mL of methanol and potassium hydroxide (1.12g, 20mmol) to the obtained methyl p-fluorobenzoylformate and react for 3h. The reaction system is vacuum distilled to remove the solvent, 30mL of deionized water is added, and washed with 30mL of dichloromethane for three times. Add an appropriate amount of dilute hydrochloric acid to the obtained aqueous phase until the pH value is about 3, extract with 30mL of dichloromethane, and extract three times. The combined organic phases were dried over anhydrous sodium sulfate, and dichloromethane was removed by distillation under reduced pressure to obtain p-fluorobenzoylformic acid.

[0229] 1 H NMR (400 MHz, CHLOROFORM-d) δ 9.03 (s, 1H), 8.55–8.43 (m, 2H), 7.28–7.20 (m, 2H).

[0230] 13 C NMR (101 MHz, chloroform-d) δ 182.45, 168.70, 166.11, 160.77, 134.65, 134.55, 128.19, 116.56.

[0231] 2.2 Synthesis of 4-fluorobenzoylformic acid acetone oxime ester

[0232] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-fluorobenzoylformic acid (1.68 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Acetone oxime (0.73 g, 10 mmol) prepared as described in Example 1 was dissolved in 10 mL of dichloromethane, slowly added dropwise to the single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by reduced pressure distillation to obtain a crude product. Then, the crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:7 mixture of ethyl acetate and petroleum ether. The effluent was distilled under reduced pressure to obtain the final product F-AOXE.

[0233] The hydrogen spectrum data of F-AOXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.10–7.98 (m, 2H), 7.21–7.12 (m, 2H), 2.03 (d, J = 6.2 Hz, 6H).

[0234] The carbon spectrum data of F-AOXE is: 13 C NMR (101 MHz, chloroform-d) δ 184.23, 168.10, 166.49, 165.54, 162.46, 132.80, 132.70, 129.01, 116.48, 116.26, 21.74, 17.20.

[0235] Example 3: Synthesis of a photoinitiator Cl-AOXE having the following structure

[0236]

[0237] 3.1 Synthesis of p-chlorobenzoylformic acid

[0238] Add methyl oxalyl chloride (1.22g, 10mmol) and aluminum chloride (1.99g, 15mmol) to a 100mL single-mouth flask, and add 30mL of dichloromethane as a solvent. Use a dropping funnel to slowly drop chlorobenzene (1.12g, 10mmol) dissolved in 30mL of dichloromethane into the aforementioned single-mouth flask, and stir at 5°C until the addition is completed. After the addition is completed, react for 5h, and then remove the solvent by vacuum distillation to obtain methyl p-chlorobenzoylformate. Add 30mL of methanol and potassium hydroxide (1.12g, 20mmol) to the obtained methyl p-chlorobenzoylformate and react for 3h. The reaction system is vacuum distilled to remove the solvent, 30mL of deionized water is added, and washed with 30mL of dichloromethane for three times. Add an appropriate amount of dilute hydrochloric acid to the obtained aqueous phase until the pH value is about 3, and then extract with 30mL of dichloromethane for three times. The combined organic phases were dried over anhydrous sodium sulfate, and dichloromethane was removed by distillation under reduced pressure to obtain p-chlorobenzoylformic acid.

[0239] 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.44 (s, 1H), 8.38–8.32 (m, 2H), 7.57–7.50 (m, 2H).

[0240] 13 C NMR (101 MHz, chloroform-d) δ 182.96, 160.89, 142.77, 132.79, 130.02, 129.47. 3.2 Synthesis of p-Chlorobenzoylformic acid acetone oxime

[0241] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-chlorobenzoylformic acid (1.84 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Acetone oxime (0.73 g, 10 mmol) prepared as described in Example 1 was dissolved in 10 mL of dichloromethane, slowly added dropwise to the single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:7 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product Cl-AOXE.

[0242] The hydrogen spectrum data of Cl-AOXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.05–7.91 (m, 2H), 7.63–7.40 (m, 2H), 2.08 (d, J = 5.0 Hz, 6H).

[0243] The carbon spectrum data of Cl-AOXE is: 13C NMR (101 MHz, chloroform-d) δ 184.63, 166.41, 162.32, 141.76, 131.25, 130.94, 129.43, 21.85, 17.29.

[0244] Example 4: Synthesis of a photoinitiator having the following structure O-AOXE

[0245]

[0246] 4.1 Synthesis of p-Anisylformic acid

[0247] Add methyl oxalyl chloride (1.22g, 10mmol) and aluminum chloride (1.99g, 15mmol) to a 100mL single-necked flask, and add 30mL of dichloromethane as a solvent. Use a dropping funnel to slowly drop anisole (1.08g, 10mmol) dissolved in 30mL of dichloromethane into a 100mL single-necked flask, and stir at 5°C until the addition is complete. After the addition is completed, react for 5h, then remove the solvent by vacuum distillation to obtain methyl p-methoxybenzoylformate. Add 30mL of methanol and potassium hydroxide (1.12g, 20mmol) to the obtained methyl p-methoxybenzoylformate and react for 3h. Remove the solvent by vacuum distillation of the reaction system, add 30mL of deionized water, wash with 30mL of dichloromethane, and wash three times. Add an appropriate amount of dilute hydrochloric acid to the obtained aqueous phase until the pH value is about 3, and then extract with 30mL of dichloromethane, and extract three times. The combined organic phases were dried over anhydrous sodium sulfate, and dichloromethane was removed by distillation under reduced pressure to obtain p-methoxybenzoylformic acid.

[0248] 1 H NMR (400 MHz, CHLOROFORM-d) δ 9.20 (s, 1H), 8.59–8.36 (m, 2H), 7.10–6.92 (m, 2H), 3.94 (s, 3H).

[0249] 13 C NMR (101 MHz, chloroform-d) δ 182.73, 165.72, 162.96, 134.06, 124.75, 114.41, 55.74.

[0250] 4.2 Synthesis of p-Anisylbenzoylformic acid acetone oxime

[0251] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-methoxybenzoylformic acid (1.80 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Acetone oxime (0.73 g, 10 mmol) prepared as described in Example 1 was dissolved in 10 mL of dichloromethane, slowly added dropwise to the single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:5 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product O-AOXE.

[0252] The hydrogen spectrum data of O-AOXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.29–7.80 (m, 2H), 7.08–6.88 (m, 2H), 3.89 (s, 3H), 2.06 (d, J = 2.1 Hz, 6H).

[0253] The carbon spectrum data of O-AOXE is: 13 C NMR (101 MHz, chloroform-d) δ 184.38, 166.24, 165.15, 162.93, 132.37, 125.42, 114.36, 55.66, 21.78, 17.19.

[0254] Example 5: Synthesis of a photoinitiator COXE having the following structure

[0255]

[0256] 5.1 Synthesis of coumarin-based ethyl ketone oxime having the following structure IV-A

[0257]

[0258] Ethyl acetoacetate (1.95 g, 15 mmol) and piperidine (0.255 g, 3 mmol) were added to a 100 mL single-necked flask, and 30 mL of anhydrous ethanol was added. 2-Hydroxy-4-methoxybenzaldehyde (1.52 g, 10 mmol) and 10 mL of anhydrous ethanol were added to a dropping funnel. At 25 ° C, the raw materials in the dropping funnel were added dropwise to the aforementioned single-necked flask, and the temperature was raised to 80 ° C after the addition was completed, and the reaction was performed for 5 h. After removing part of the solvent by rotary evaporation, recrystallization was performed to obtain 3-acetyl 7-methoxycoumarin. 3-Acetyl 7-methoxycoumarin (2.18 g, 10 mmol) and hydroxylamine hydrochloride (1.05 g, 15 mmol) were added to a 100 mL single-necked flask, 30 mL of ethanol was added, and the reaction was performed at room temperature for 5 h. Excess ethanol was removed by vacuum distillation to obtain coumarin-based ethyl ketone oxime of formula IV-A.

[0259] 1 H NMR (400MHz, DMSO-d6) δ11.33(s,1H),8.02(s,1H),7.70(d,J=8.6Hz,1H),7.00(d,J=2.4Hz,1H),6.96(dd,J=8.6,2.4Hz,1H),3.86(s,3H),2.07(s,3H).

[0260] 13 C NMR (101MHz, DMSO-d6) δ163.16,159.87,155.72,152.27,141.54,130.49,121.98,113.20,112.76,100.78,56.44,13.95.

[0261] 5.2 Synthesis of benzoylformic acid coumarinyl ethyl ketone oxime ester

[0262] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), benzoylformic acid (1.50 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Coumarin-based ethyl ketone oxime (2.33 g, 10 mmol) of formula IV-A was dissolved in 10 mL of dichloromethane, slowly added dropwise to the aforementioned single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:3 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product COXE.

[0263] The hydrogen spectrum data of COXE is: 1H NMR (400 MHz, CHLOROFORM-d) δ 8.11–8.02 (m, 2H), 7.96 (s, 1H), 7.74–7.66 (m, 1H), 7.56 (t, J = 7.8 Hz, 2H), 7.43 (d, J = 8.7 Hz, 1H), 6.89 (dd, J = 8.7, 2.4 Hz, 1H), 6.82 (d, J = 2.4 Hz, 1H), 3.90 (s, 3H), 2.47 (s, 3H).

[0264] The carbon spectrum data of COXE is: 13 C NMR (101 MHz, chloroform-d) δ 185.64, 164.65, 164.19, 159.29, 156.53, 143.88, 135.24, 132.42, 130.70, 130.24, 129.95, 129.12, 118.76, 113.54, 111.98, 100.55, 55.96, 16.09.

[0265] Example 6: Synthesis of a photoinitiator F-COXE having the following structure

[0266]

[0267] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-fluorobenzoylformic acid (1.68 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-mouth flask, and 30 mL of dichloromethane was added as a solvent. The coumarin-based ethyl ketone oxime (2.33 g, 10 mmol) of formula IV-A prepared as described in Example 5 was dissolved in 10 mL of dichloromethane, slowly added dropwise to the aforementioned single-mouth flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:4 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product F-COXE.

[0268] The hydrogen spectrum data of F-COXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.19–8.09 (m, 2H), 8.01 (s, 1H), 7.48 (d, J = 8.6 Hz, 1H), 7.25 (t, J = 8.6 Hz, 2H), 6.92 (dd, J = 8.7, 2.4 Hz, 1H), 6.85 (d, J = 2.4 Hz, 1H), 3.92 (s, 3H), 2.50 (s, 3H).

[0269] The carbon spectrum data of F-COXE is: 13C NMR (101 MHz, chloroform-d) δ 183.77, 168.29, 165.72, 164.89, 164.22, 161.88, 159.23, 156.57, 143.84, 132.94, 132.85, 130.23, 128.98, 118.78, 116.64, 116.42, 113.57, 111.97, 100.57, 55.96, 16.13.

[0270] Example 7: Synthesis of a photoinitiator Cl-COXE having the following structure

[0271]

[0272] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-chlorobenzoylformic acid (1.84 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Coumarin-based ethyl ketone oxime (2.33 g, 10 mmol) of formula IV-A prepared as described in Example 5 was dissolved in 10 mL of dichloromethane, slowly added dropwise to the single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:4 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product Cl-COXE.

[0273] The hydrogen spectrum data of the photoinitiator Cl-COXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.04 (d, J = 8.3 Hz, 2H), 8.00 (s, 1H), 7.56 (d, J = 8.4 Hz, 2H), 7.48 (d, J = 8.6 Hz, 1H), 6.92 (dd, J = 8.7, 2.3 Hz, 1H), 6.86 (d, J = 2.4 Hz, 1H), 3.93 (s, 3H), 2.50 (s, 3H).

[0274] Example 8: Synthesis of a photoinitiator O-COXE having the following structure

[0275]

[0276] Dicyclohexylcarbodiimide (2.47 g, 12 mmol), p-methoxybenzoylformic acid (1.80 g, 10 mmol) and 4-dimethylaminopyridine (0.12 g, 1 mmol) were added to a 100 mL single-necked flask, and 30 mL of dichloromethane was added as a solvent. Coumarin-based ethyl ketone oxime (2.33 g, 10 mmol) of formula IV-A prepared as described in Example 5 was dissolved in 10 mL of dichloromethane, slowly added dropwise to a single-necked flask, stirred at 25 ° C until the addition was completed, filtered to remove the white precipitate, and the solvent was removed by vacuum distillation to obtain a crude product. The crude product was dissolved in dichloromethane and purified by silica gel column chromatography, and the eluent was a 1:2 mixture of ethyl acetate and petroleum ether. The effluent was vacuum distilled to obtain the final product O-COXE.

[0277] The hydrogen spectrum data of O-COXE is: 1 H NMR (400 MHz, CHLOROFORM-d) δ 8.09–8.04 (m, 2H), 8.03 (s, 1H), 7.47 (d, J = 8.7 Hz, 1H), 7.08–7.00 (m, 2H), 6.91 (dd, J = 8.6, 2.4 Hz, 1H), 6.84 (d, J = 2.4 Hz, 1H), 3.93 (s, 3H), 3.92 (s, 3H), 2.48 (s, 3H).

[0278] The carbon spectrum data of O-COXE is: 13 C NMR (101 MHz, chloroform-d) δ 183.91, 165.31, 164.59, 164.14, 159.29, 156.54, 143.82, 132.56, 130.23, 125.48, 118.95, 114.47, 113.51, 112.03, 100.56, 55.95, 55.73, 16.10.

[0279] Example 9: UV absorption characterization

[0280] Prepare 50 mL of anhydrous acetonitrile solution of the photoinitiators synthesized in Examples 1 to 4 (i.e., AOXE, F-AOXE, Cl-AOXE, and O-AOXE) at a concentration of 1×10 -4 mol / L. The absorption curves of the four solutions in the wavelength range of 200 to 450 nm, namely, the UV-visible absorption spectra, were tested using an ultraviolet spectrophotometer (Shimadzu Corporation, Japan, model UV-3600).

[0281] The UV-visible absorption spectra of these four photoinitiators are shown in Figure 2. Figure 2 As shown. Figure 2From the partial screenshot within the wavelength range of 360nm to 440nm, it can be seen that these four photoinitiators have certain weak absorption around 400nm. This weak absorption can not only give the initiator the initiation ability at the LED emission wavelength, but also facilitate its application in curing systems requiring colorless and deep polymerization.

[0282] Example 10: UV absorption characterization

[0283] Prepare 50 mL of anhydrous acetonitrile solution of the photoinitiators (i.e., COXE, F-COXE, Cl-COXE, and O-COXE) synthesized in Examples 5 to 8, respectively, with a concentration of 1×10 -4 mol / L. The absorption curves of the four solutions in the wavelength range of 200 to 500 nm, namely, the UV-visible absorption spectra, were tested using an ultraviolet spectrophotometer (Shimadzu Corporation, Japan, model UV-3600).

[0284] The UV-visible absorption spectra of these four photoinitiators are shown in Figure 2. Figure 3 As shown. Figure 3 From the local screenshot in the wavelength range of 430nm to 470nm, it can be seen that the maximum absorption wavelength of these four photoinitiators is around 200nm, but they also have certain weak absorption around 455nm, which will be beneficial to their application under high-wavelength light sources.

[0285] Example 11: Photopolymerization Test

[0286] The photoinitiators synthesized in Examples 1 to 8 were applied to an acrylate polymerization system to test the performance of these photoinitiators in LED photopolymerization.

[0287] 11.1 Preparation of photosensitive solution

[0288] The photoinitiator and tripropylene glycol diacrylate monomer were mixed at a mass ratio of 1:100, and stirred evenly to prepare a photosensitive solution.

[0289] 11.2 Performance test of photopolymerization initiation

[0290] The prepared photosensitive liquid was evenly applied on the potassium bromide salt sheet, and the coating thickness was about 30 μm. Then the potassium bromide salt sheet was covered on the coating. A real-time infrared spectrometer (Thermo Fisher Scientific, USA, model Nicolet 5700) was used to detect the photosensitive liquid under the LED light source (Shenzhen Lanpulic Technology Co., Ltd., model UVEC-4II, light intensity 80 mW / cm 2 ) polymerization under irradiation.

[0291] The aggregate test results are shown in Figure 4 , Figure 5 , Figure 6 and Figure 7 middle.

[0292] Figure 4 Shown is the photopolymerization kinetics of tripropylene glycol diacrylate initiated by the photoinitiators AOXE, F-AOXE, Cl-AOXE and O-AOXE synthesized in Examples 1 to 4 and the commercially available photoinitiator OXE-01 (purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.) under a 385nm LED light source.

[0293] Figure 5 Shown are the photopolymerization kinetics of tripropylene glycol diacrylate initiated by the photoinitiators AOXE, F-AOXE, Cl-AOXE and O-AOXE synthesized in Examples 1 to 4 and the commercially available photoinitiator OXE-01 under a 405 nm LED light source.

[0294] Figure 6 Shown is the photopolymerization kinetics of tripropylene glycol diacrylate monomer initiated by COXE, F-COXE, Cl-COXE and O-COXE synthesized in Examples 5 to 8 and commercially available photoinitiator OXE-01 under a 405 nm LED light source.

[0295] Figure 7 Shown are the photopolymerization kinetics of tripropylene glycol diacrylate initiated by COXE, F-COXE, Cl-COXE and O-COXE in Examples 5 to 8 and the commercially available photoinitiator OXE-01 under a 455 nm LED light source.

[0296] Depend on Figures 4 to 7 It can be seen that the photoinitiator of the present invention can effectively initiate the polymerization reaction of acrylate monomers under the irradiation of LED light source, which shows that the photoinitiator of the present invention has good initiation performance and applicability under the LED photopolymerization system.

[0297] Example 12: Deep photopolymerization test

[0298] The photoinitiator F-AOXE synthesized in Example 2 and the commercially available OXE-01 were respectively applied to the acrylate polymerization system to test the performance of these photoinitiators in initiating deep polymerization under the irradiation of LED light source.

[0299] The two photoinitiators were respectively mixed with tripropylene glycol diacrylate monomer at a mass ratio of 1:100, and stirred evenly to prepare a photosensitive solution.

[0300] The two photosensitive solutions were injected into glass tubes with a depth of 7.5 cm and a diameter of 0.7 cm. A 405 nm LED light source was used to illuminate the bottom of the tube, and the distance from the light source to the bottom of the glass tube was 4 cm. After irradiation for 60 seconds and 100 seconds, the depth of the polymerized polytripropylene glycol diacrylate in the test tube was measured. The test results are shown in the attached figure. Figure 7 shown.

[0301] Under the aforementioned conditions, the polymerization depths of the photosensitive composition using the photoinitiator F-AXOE of the present invention after irradiation for 60s and 100s were 3.2cm and 6.65cm, respectively. Under the same conditions, the polymerization depths of the photosensitive composition using the commercially available photoinitiator OXE-01 were only 0.5cm and 3cm. This indicates that the photoinitiator of the present invention has a significantly improved ability to initiate deep polymerization under the LED photopolymerization system.

[0302] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. Various process schemes that are not substantially different from the concept of the present invention are within the protection scope of the present invention.

Claims

1. An aromatic formyl formic acid oxime ester compound having a structure shown in formula (I): in, Ar is C6-C 10 -aryl, or a C6-C 10 -Aryl: halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups; R1 and R2 are independently selected from hydrogen, Q, C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl, the aforementioned C1-C 16 -alkyl, C3-C 10 -cycloalkyl, C3-C 10 -cycloalkyl-C1-C 16 -alkyl and C1-C 16 -alkyl-C3-C 10 -cycloalkyl is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino group, wherein R1 and R2 are not simultaneously any of hydrogen and Q, Q is a coumarin group or a coumarin keto group having a structure represented by formula (II): wherein R3, R4, R5, R6 and R7 are independently selected from hydrogen, halogen, nitro, hydroxyl, thiol, amino, C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino, the aforementioned C1-C 16 -alkyl, C1-C 16 -alkoxy, C1-C 16 -alkylthio, mono(C1-C 16 -alkyl)amino and di(C1-C 16 -alkyl)amino is optionally substituted by at least one selected from halogen, nitro, hydroxy, mercapto, amino and C6-C 10 - aryl radical substitution, n is 0 or 1, and * indicates the position where the group Q is attached to other moieties.

2. The aromatic formyl formate oxime compound according to claim 1, wherein in formula (I), Ar is a phenyl or naphthyl group which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, nitro, hydroxyl, sulfhydryl, C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio, the aforementioned C1-C 12 -alkyl, C1-C 12 -alkoxy and C1-C 12 -alkylthio is optionally substituted with at least one selected from halogen, hydroxy, mercapto, amino and C6-C 10 - radical substitution of aryl groups; Preferably, Ar is phenyl or naphthyl which is unsubstituted or substituted by at least one group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one group selected from the group consisting of halogen, nitro, hydroxyl, mercapto, amino and C6-C 10 - radical substitution of aryl groups; More preferably, Ar is phenyl or phenyl substituted by at least one, preferably one, group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio optionally being substituted by at least one group selected from halogen, hydroxyl and mercapto; Most preferably, Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio, in particular, Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio.

3. The aromatic formyl formate oxime ester compound according to claim 1 or 2, wherein in formula (I), R1 and R2 are independently selected from hydrogen, Q, C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl, the aforementioned C1-C 12 -alkyl, C3-C6-cycloalkyl, C3-C6-cycloalkyl-C1-C 12 -alkyl and C1-C 12 -alkyl-C3-C6-cycloalkyl is optionally substituted with at least one selected from halogen, nitro, hydroxy, mercapto, amino, C1-C 12 -alkoxy, C1-C 12 -alkylthio, mono(C1-C 12 -alkyl)amino and di(C1-C 12 -alkyl)amino group substitution; Preferably, R1 and R2 are independently selected from hydrogen, Q, C1-C8-alkyl or C1-C8-alkyl substituted by at least one group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkoxy and C1-C6-alkylthio; More preferably, R1 is hydrogen or C1-C6-alkyl, R2 is C1-C6-alkyl or Q; in particular, R1 is C1-C4-alkyl, such as methyl or ethyl, R2 is C1-C4-alkyl or Q, such as methyl or ethyl; in R1 and R2 are not simultaneously any of hydrogen and a group Q.

4. The aromatic carboxylic acid oxime ester compound according to any one of claims 1 to 3, wherein in formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio, wherein the aforementioned C1-C8-alkyl, C1-C8-alkoxy and C1-C8-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and n is 0; Preferably, in formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkoxy or C1-C6-alkylthio, and n is 0; More preferably, in formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

5. The aromatic formyl formate oxime ester compound according to any one of claims 1 to 4, wherein in formula (I), Ar is phenyl or phenyl substituted by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, R1 is hydrogen or C1-C6-alkyl, R2 is a C1-C6-alkyl group or Q, wherein Q is a coumarin group having a structure shown in formula (II), In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio, wherein the aforementioned C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio are optionally substituted by at least one selected from halogen, hydroxyl, mercapto and C6-C 10 - aryl radical substitution, and n is 0; Preferably, in the aforementioned formula (I), Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxyl, mercapto, C1-C6-alkyl, C1-C6-alkoxy and C1-C6-alkylthio.

6. The aromatic formylformic acid oxime ester compound according to claim 5, wherein in formula (I), Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of halogen, hydroxy, mercapto, C1-C4-alkyl, C1-C4-alkoxy and C1-C4-alkylthio, R1 is hydrogen or C1-C4-alkyl, R2 is a C1-C4-alkyl group or Q, wherein the group Q is a coumarin group having a structure shown in formula (II), In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from halogen, hydroxyl, mercapto, C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

7. The aromatic carboxylic acid oxime ester compound according to claim 6, wherein in formula (I), Ar is phenyl or phenyl substituted in the para position by a group selected from the group consisting of fluorine, chlorine, C1-C4-alkoxy and C1-C4-alkylthio, R1 is C1-C4-alkyl, R2 is a C1-C4-alkyl group or Q, wherein Q is a coumarin group having a structure shown in formula (II), In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from C1-C4-alkoxy or C1-C4-alkylthio, and n is 0.

8. The aromatic formylformic acid oxime ester compound according to claim 7, wherein in formula (I), Ar is phenyl, p-fluorophenyl, p-chlorophenyl, p-methoxyphenyl or p-ethoxyphenyl, R1 is methyl or ethyl, R2 is methyl, ethyl or Q, wherein Q is a coumarin group having a structure shown in formula (II), In formula (II), R3, R5, R6 and R7 are hydrogen, R4 is selected from methoxy, ethoxy, methylthio or ethylthio, and n is 0.

9. The aromatic carboxylic acid oxime ester compound according to any one of claims 1 to 8, wherein both R1 and R2 are not Q.

10. The aromatic carboxylic acid oxime ester compound according to any one of claims 1 to 8, wherein R2 is Q.

11. A method for preparing an arylformic acid oxime ester compound according to any one of claims 1 to 10, the method comprising subjecting an arylformic acid represented by formula (III) to an oxime represented by formula (IV) for esterification reaction: in, Ar in formula (III) and R1 and R2 in formula (IV) have the same meanings as Ar, R1 and R2 in formula (I), respectively.

12. A composition for LED light curing, comprising: - at least one aromatic oxime formate compound according to any one of claims 1 to 10 as a photoinitiator, and - a photocurable component selected from at least one of monomers, oligomers and prepolymers having ethylenically unsaturated functions, in, The mass ratio of the photoinitiator to the photocurable component is in the range of 0.2:100 to 6:100, preferably in the range of 0.5:100 to 5:100, and especially in the range of 1:100 to 3:

100.

13. A composition according to claim 12, wherein the monomer is selected from at least one of the following groups: monofunctional ethylenically unsaturated compounds, such as (meth)acrylic acid and its salts, (meth)acrylates, (meth)acrylamide, N-substituted (meth)acrylamide, (meth)acrylonitrile, anhydrides and esters of unsaturated carboxylic acids other than (meth)acrylic acid, styrene and substituted styrenes, vinyl ethers and halogenated vinyls, vinyl and allyl esters of carboxylic acids; and polyfunctional ethylenically unsaturated compounds, such as (meth)acrylic type monomers such as di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates and penta(meth)acrylates.

14. The composition according to claim 12, wherein the prepolymer or oligomer is at least one selected from the group consisting of epoxy (meth) acrylic resins, polyurethane (meth) acrylic resins, polyester (meth) acrylic resins, polyether (meth) acrylic resins, and acrylated poly (meth) acrylic resins.

15. Use of the aromatic formyl formic acid oxime ester compound according to any one of claims 1 to 10 as a photoinitiator in an LED light curing system, especially in a colorless LED light curing system and a deep curing LED light curing system.

16. Use of the aromatic formyl formic acid oxime ester compound according to claim 9 in an LED light curing system requiring deep curing.

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