Formylformic acid coumarin compounds, methods of making and uses thereof, and photoinitiator compositions and photocurable compositions comprising the same

Abstract

The present application relates to a 3-formylformic acid coumarin compound of formula (I), a preparation method and uses thereof, a photoinitiator composition and a photocurable composition comprising the same, a cured material obtainable from the photocurable composition, and a method for preparing a photocured material. The compound of the present application can be used as an oil-soluble photoinitiator and an aqueous photoinitiator, has obvious advantages in photosensitivity, is suitable for use as a photoinitiator for UV-VIS LED light source curing, can initiate free radical polymerization, and can also sensitize onium salt compounds such as iodonium salt or sulfonium salt to initiate cationic polymerization of epoxy monomers or oxetane monomers.

Description

Technical Field

[0001] This invention belongs to the field of photocuring technology and relates to a 3-formylcoumarin compound. This compound can be used as both an aqueous and an oil-soluble photoinitiator, and is particularly suitable for curing UV-VIS LED light sources. This invention also relates to the preparation and uses of the 3-formylcoumarin compound, photoinitiator compositions containing it, photocurable compositions, cured materials obtainable from the photocurable compositions, and methods for preparing photocurable materials. Background Technology

[0002] Photoinitiators, also known as photosensitizers or photocuring agents, are compounds that absorb energy of a certain wavelength in the ultraviolet (250-400nm) or visible (400-600nm) light region, generating free radicals, cations, etc., thereby initiating monomer polymerization, cross-linking, and curing. As an important component of photocuring systems, although photoinitiators are present in low concentrations, they are crucial components that determine the photocuring rate and must meet the needs of different photocuring conditions and applications. They determine whether the formulation system can rapidly cross-link and cure under light irradiation, thus transforming from a liquid to a solid state. Furthermore, with the widespread application of photocuring technology in traditional fields such as coatings, inks, microelectronics, and printing, as well as in emerging fields such as the fabrication of laser recording and 3D components, and with the continuous development of UV-VIS LED light source curing technology, it is necessary to develop photoinitiators suitable for UV-VIS LED light sources to meet the diverse application requirements of UV-VIS LED light source curing technology.

[0003] Traditional photocuring systems typically require reactive diluents (monomers) to reduce resin viscosity. However, some monomers are volatile, producing toxicity and odor, which can cause environmental pollution. Water, on the other hand, is non-toxic and low-cost, making waterborne photocuring systems a focus of research due to environmental concerns. Waterborne photocuring systems exhibit lower irritation and odor, and their viscosity is easily adjustable. Currently, most photoinitiators on the market are oil-soluble, which has poor compatibility with water-soluble resins, inevitably affecting the final performance of the cured product. Waterborne photoinitiators, however, are low-pollution and environmentally friendly; therefore, research on waterborne photoinitiators holds great promise for future applications.

[0004] Furthermore, cationic photoinitiators induce cationic photocuring reactions with advantages such as antioxidant inhibition, low shrinkage, good adhesion and chemical resistance, and relatively thorough curing. Therefore, cationic photocuring technology is widely used in electronic products, metal decoration, adhesives, inks, and other fields. Ononium salts, especially thioonium and iodonium salts, are important photoacid generators and are widely used in cationic photocuring. However, the short ultraviolet absorption slope of these substances limits their application under long-wavelength ultraviolet-visible LED light sources. Photosensitizers are typically used to expand their application range, but photoinitiators that can sensitize thioonium salts are few. Currently reported photoinitiators are mostly anthraquinones, which have a polybenzene ring structure and exhibit certain reproductive toxicity. There is an urgent need to develop suitable photoinitiators. Summary of the Invention

[0005] One object of the present invention is to provide a 3-formylcarboxylic acid coumarin compound of formula (I), which can be used as a photoinitiator, such as a cleavage-type photoinitiator or a hydrogen-abstraction-type photoinitiator to initiate free radical photopolymerization, or as a photoinitiator to sensitize onium salt photoinitiators to initiate cationic photopolymerization. The absorption wavelength of the compound of the present invention is not only suitable for UV-VIS LED light source radiation curing, but also has excellent hydrophilicity and lipophilicity, and can be used as both aqueous and oil-soluble photoinitiators.

[0006] Another object of the present invention is to provide a method for preparing the 3-formylcoumarin compound of formula (I) of the present invention.

[0007] Another object of the present invention is to provide the use of the 3-formylcoumarin compound of formula (I) of the present invention as a photoinitiator.

[0008] Another object of the present invention is to provide a photoinitiator composition comprising the 3-formylcoumarin compound of formula (I) of the present invention.

[0009] Another object of the present invention is to provide a photocurable composition comprising a 3-formylcoumarin compound of formula (I) of the present invention or a photoinitiator composition of the present invention.

[0010] Another object of the present invention is to provide a curable material that can be obtained from the photocurable composition of the present invention.

[0011] Another object of the present invention is to provide a method for preparing photocurable materials.

[0012] The technical solution for achieving the above-mentioned objectives of this invention can be summarized as follows:

[0013] 1. The 3-formylcoumarin compound of formula (I):

[0014]

[0015] in:

[0016] R1 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0017] R2 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0018] R3 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0019] R4 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are not substituted or contain one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, and C1-C6 alkoxy(thio) group; and

[0020] R5 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0021] or

[0022] R1 and R2, R2 and R3, or R3 and R4 together with the carbon atoms they are bonded to form a 3, 4, 5, 6, or 7 partially unsaturated or aromatic carbocyclic or heterocyclic ring fused with the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of halogens, C1-C6 alkyl groups, and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members;

[0023] or

[0024] R1, R2, and R3, or R2, R3, and R4 together with the carbon atoms they are bonded to form a 6, 7, 8, 9, or 10 partially unsaturated or aromatic bicarbonate ring or biheterocycle fused to the benzene ring in the coumarin structure, wherein the bicarbonate ring or biheterocycle is not substituted or contains one or more substituents independently selected from the group consisting of halogens, C1-C6 alkyl groups, and C1-C6 alkoxy(sulfo) groups, and the biheterocycle contains one or two heteroatoms selected from N, O, and S as ring members.

[0025] 2. A 3-formylcoumarin compound according to formula (I) of item 1, wherein:

[0026] R1 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0027] R2 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0028] R3 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are not substituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; and

[0029] R4 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0030] R5 is H or a linear or branched C1-C. 16 alkyl;

[0031] or

[0032] R1 and R2, R2 and R3, or R3 and R4 together with the carbon atoms they are bonded to form a 5, 6, or 7 partially unsaturated or aromatic carbocyclic or heterocyclic ring fused to the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members;

[0033] or

[0034] R1, R2, and R3, or R2, R3, and R4 together with the carbon atoms they are bonded to form an 8, 9, or 10-member partially unsaturated or aromatic bicarbonate ring or biheterocycle fused to the benzene ring in the coumarin structure, wherein the bicarbonate ring or biheterocycle is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the biheterocycle contains one or two heteroatoms selected from N, O, and S as ring members.

[0035] 3. A 3-formylcoumarin compound of formula (I) according to item 1 or 2, wherein:

[0036] R1 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(sulfur) group; wherein all of the aforementioned groups except H are not substituted or included

[0037] Contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; R2 is H, straight-chain or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0038] R3 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(sulfur) group; wherein all of the aforementioned groups except H are not substituted or included

[0039] Contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; R4 is H, straight-chain or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are not substituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; and

[0040] R5 is H or a linear or branched C1-C. 16 alkyl;

[0041] or

[0042] R1 and R2, R2 and R3, or R3 and R4 together with the carbon atoms they are bonded to form a 5, 6, or 7 partially unsaturated carbocyclic or heterocyclic ring fused with the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members;

[0043] or

[0044] R1, R2, and R3, or R2, R3, and R4 (preferably R1, R2, and R3), together with the carbon atoms they are bonded to, form an 8, 9, or 10-member partially unsaturated bicarbonyl ring or biheterocyclic ring fused with the benzene ring in the coumarin structure, wherein the bicarbonyl ring or biheterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the biheterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members.

[0045] 4. A 3-formylcoumarin compound of formula (I) according to any one of items 1-3, wherein:

[0046] R1 is H, linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl, or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0047] R2 is H, linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl, mono- or di-C1-C4 alkylamino or C1-C 12 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups;

[0048] R3 is H, linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl or C1-C 16 Alkoxy(sulfur) group; wherein all of the aforementioned groups except H are not substituted or included

[0049] Contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; R4 is H, straight-chain or branched C1-C12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are not substituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups; and

[0050] R5 is H or a linear or branched C1-C. 12 alkyl;

[0051] or

[0052] R1 and R2, R2 and R3, or R3 and R4 together with the carbon atoms they are bonded to form a 5, 6, or 7 partially unsaturated carbocyclic or heterocyclic ring fused with the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members;

[0053] or

[0054] R1, R2, and R3, or R2, R3, and R4 together with the carbon atoms they are bonded to form an 8, 9, or 10-member partially unsaturated bicarbonyl ring or biheterocyclic ring fused to the benzene ring in the coumarin structure, wherein the bicarbonyl ring or biheterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the biheterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members.

[0055] 5. A 3-formylcoumarin compound of formula (I) according to any one of items 1-4, wherein:

[0056] R1 is H or a linear or branched C1-C. 12 alkyl;

[0057] R2 is H, linear or branched C1-C 12 Alkyl, diC1-C4 alkylamino or C1-C 16 Alkoxy(sulfide) group;

[0058] R3 is H, linear or branched C1-C 12 Alkyl or C1-C 16 Alkoxy(sulfide) group;

[0059] R4 is H, linear or branched C1-C 12 Alkyl or C1-C 16 alkoxy(thio) group; and R5 is H;

[0060] or

[0061] R1, R2, and R3, or R2, R3, and R4 together with their bonded carbon atoms form an 8, 9, or 10-member partially unsaturated biheterocycle fused to the benzene ring in the coumarin structure, wherein the biheterocycle is unsubstituted or contains one or more substituents independently selected from the group consisting of C1-C4 alkyl groups, the biheterocycle containing one N heteroatom as a ring member, preferably the N heteroatom being a shared atom of the biheterocycle; more preferably the biheterocycle has the structure of formula (a):

[0062]

[0063] in

[0064] * indicates the position where the coumarin structure is fused with the benzene ring; and

[0065] The structure shown in formula (a) is not substituted or contains one or more C1-C4 alkyl groups as substituents.

[0066] 6. A 3-formylcoumarin compound of formula (I) according to any one of items 1-5, wherein at least one of R1, R2, R3 and R4 is not H and R5 is H, or preferably two or three of R1, R2, R3 and R4 are H and R5 is H.

[0067] 7. A 3-formylcoumarin compound of formula (I) according to any one of claims 1-5, wherein the 3-formylcoumarin compound of formula (I) is selected from the group consisting of:

[0068]

[0069]

[0070] 8. A method for preparing a 3-formylcoumarin compound of formula (I) as described in any one of claims 1-7, comprising the following steps:

[0071] (1) Knoevenagel condensation reaction: Compound (II) is subjected to a Knoevenagel condensation reaction with a C1-C6 alkyl ester of acetoacetic acid to obtain compound (III):

[0072]

[0073] (2) Oxidation reaction: The compound of formula (III) is oxidized with an oxidizing agent to obtain the compound of formula (I).

[0074]

[0075] In the above formulas, R1, R2, R3, R4 and R5 are defined as in any of the terms 1-7.

[0076] 9. According to the method in item 8, where:

[0077] The Knauvengay condensation reaction in step (1) is carried out in the presence of one or more catalysts selected from the group consisting of: amines such as primary amines, secondary amines, tertiary amines and their corresponding ammonium salts, preferably piperidine; inorganic bases such as alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal carbonates and alkali metal or alkaline earth metal bicarbonates; inorganic salts such as potassium fluoride, aluminum phosphate, diammonium hydrogen phosphate; Lewis acid and tertiary amine conjugates such as TiCl4 / piperidine or TiCl4 / triethylamine.

[0078] 10. The method according to item 8 or 9, wherein in the Knauvengel condensation reaction in step (1), the molar ratio of the compound of formula (II) to the C1-C6 alkyl ester of acetoacetic acid is 1:0.1-1:10, preferably 1:0.3-1:5, more preferably 1:0.9-1:3.

[0079] 11. The method according to any one of items 8-10, wherein in the oxidation reaction of step (2), the molar ratio of compound (III) to oxidant is 1:1-1:5, preferably 1:1-1:3.

[0080] 12. The method according to any one of items 8-11, wherein the oxidant in step (2) is selected from selenium dioxide and acidic peroxides, such as acidic hydrogen peroxide and acidic alkali metal peroxides.

[0081] 13. Use of the 3-formylcoumarin compound of formula (I) as any one of items 1-7 as a photoinitiator.

[0082] 14. According to the use of item 13, the 3-formylcoumarin compound of formula (I) is used as a pyrolytic photoinitiator in UV-VIS LED light source curing systems, particularly in light source curing systems with radiation wavelengths of 300-550 nm, especially 365-475 nm.

[0083] 15. According to the use of item 13, the 3-formylcoumarin compound of formula (I) is used as a hydrogen-abstracting photoinitiator in UV-VIS LED light source curing systems, particularly in light source curing systems with radiation wavelengths of 300-550 nm, especially 365-475 nm.

[0084] 16. According to the use of item 15, wherein the 3-formylcoumarin compound of formula (I) is used in combination with a compound selected from tertiary amine compounds, α-amino acid compounds or thiols.

[0085] 17. Use of the 3-formylcoumarin compound of formula (I) as a photoinitiator sensitized onium salt as described in any one of items 1-7, particularly as a photoinitiator sensitized onium salt in UV-VIS LED light source curing systems, especially as a photoinitiator sensitized onium salt in light source curing systems with radiation wavelengths of 300-550 nm, particularly 365-475 nm.

[0086] 18. According to the use of item 17, the onium salt is selected from iodonium salts and thiodonium salts, preferably from diaryliodonium salts and triarylthiodonium salts.

[0087] 19. According to the use of item 17 or 18, wherein the onium salt sensitized with the 3-formylcoumarin compound of formula (I) is used to initiate a free radical photopolymerization reaction, or to initiate a cationic photopolymerization reaction, or to initiate a free radical-cationic hybrid photopolymerization reaction.

[0088] 20. A photoinitiator composition comprising a 3-formylcoumarin compound of formula (I) of any one of claims 1-7.

[0089] 21. The photoinitiator composition according to claim 20, wherein the composition comprises a 3-formylcoumarin compound of formula (I) and a compound selected from tertiary amine compounds, α-amino acid compounds or thiols.

[0090] 22. The photoinitiator composition according to claim 20, wherein the photoinitiator composition comprises a 3-formylcoumarin compound of formula (I) and an onium salt, preferably selected from iodonium salts and thiodonium salts, more preferably selected from diaryliodonium salts and triarylthiodonium salts.

[0091] 23. A photocurable composition comprising at least one 3-formylcoumarin compound of formula (I) as described in any one of claims 1-7 or a photoinitiator composition as described in any one of claims 20-22.

[0092] 24. A cured material that can be obtained from the photocurable composition described in item 23.

[0093] 25. A method for preparing a photocurable material, comprising irradiating the photocurable composition of claim 23 with a light source having a radiation wavelength of 300-550 nm, particularly 365-475 nm, such as a UV-VIS LED light source.

[0094] The 3-formylcarboxylic acid coumarin compound of formula (I) of this invention comprises both a coumarin group and a 3-formylcarboxylic acid group. This compound exhibits good photosensitivity in the 300-550 nm range, particularly 365-475 nm. Upon absorbing light energy, it rapidly undergoes cleavage to generate active free radicals, continuously initiating polymerization. It can also rapidly (e.g., within seconds) initiate the polymerization of polymerizable monomers, completing the polymerization reaction within a short time (e.g., 10 minutes, especially 3 minutes). The 3-formylcarboxylic acid coumarin compound of formula (I) of this invention also possesses excellent sensitization properties, enabling it to transfer energy to other co-initiators, such as hydrogen donors or onium salts, after absorbing light energy, initiating free radical polymerization or cationic polymerization. The 3-formylcoumarin compound of formula (I) of this invention can be used as both an oil-soluble and an aqueous photoinitiator, and can initiate deep curing of monomers (such as oil-soluble acrylate monomers or aqueous acrylate monomers) at low concentrations (e.g., 0.01% by mass). Therefore, it has significant advantages in photosensitivity and is suitable as a photoinitiator for curing UV-VIS LED light sources. The compound of formula (I) of this invention is safe and non-toxic, and compared with traditional photoinitiators, it reduces the harm to human health and the environment, and can also be used in food packaging and other fields. Attached image description:

[0095] Figure 1 The UV-Vis absorption spectra of the 3-formylcoumarin compounds in acetonitrile for Examples 1-3 are shown.

[0096] Figure 2 The graph shows the monomer conversion rate versus exposure time for the free radical photopolymerization of acrylate monomers initiated by the 3-formylcoumarin compound of the present invention as a photoinitiator; wherein (a) the compound of Example 3 was used as a photoinitiator (1% w / w) to initiate TPGDA polymerization under different light sources; (b) the compounds of Examples 1-3 were used as photoinitiators / EDB (1% / 1.16% w / w) at 415 nm and 50 mW / cm. 2 (c) TPGDA polymerization initiated under a light source; (d) Compounds from Examples 1-3 as photoinitiators / GR54 (2% / 4% w / w) at 415 nm, 100 mW / cm 2 PEG(400)DA polymerization was initiated under LED light source;

[0097] Figure 3The graph shows the relationship between monomer conversion and exposure time for the ring-opening polymerization of epoxy monomer 6110 initiated by sensitized iodine and thiodine salts of the 3-formylcoumarin compound of the present invention; wherein (a) the compound of Example 1 or 3 / iodine salt GR54 (0.2% / 4% w / w) or iodine salt GR54 only; (b) the compound of Examples 1-3 / thiodine salt GR-SS061 (0.2% / 4% w / w) or thiodine salt GR-SS061 only; wherein the light source is a 415nm LED with a light intensity of 100mW / cm. 2 LED;

[0098] Figure 4 Photographs showing the deep curing initiated by the 3-formylcoumarin compounds of Examples 1 and 2; wherein (a) the length of deep curing of TPGDA initiated by 0.01% of the compound of Example 1; (b) the length of deep curing of TPGDA initiated by 0.01% of the compound of Example 2; (c) the length of deep curing of PEG(400)DA initiated by 0.01% of the compound of Example 1; and (d) the length of deep curing of PEG(400)DA initiated by 0.01% of the compound of Example 2; wherein the light source was 415 nm and 100 mW / cm. 2 . Detailed Implementation

[0099] The 3-formylcoumarin compound of formula (I):

[0100]

[0101] in:

[0102] R1 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0103] R2 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0104] R3 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0105] R4 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are not substituted or contain one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, and C1-C6 alkoxy(thio) group; and

[0106] R5 is H, linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, C6-C 10 aryl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6 alkoxy(thio) group;

[0107] or

[0108] R1 and R2, R2 and R3, or R3 and R4 together with the carbon atoms they are bonded to form a 3, 4, 5, 6, or 7 partially unsaturated or aromatic carbocyclic or heterocyclic ring fused with the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of halogens, C1-C6 alkyl groups, and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members;

[0109] or

[0110] R1, R2, and R3, or R2, R3, and R4 together with the carbon atoms they are bonded to form a 6, 7, 8, 9, or 10 partially unsaturated or aromatic bicarbonate ring or biheterocycle fused to the benzene ring in the coumarin structure, wherein the bicarbonate ring or biheterocycle is not substituted or contains one or more substituents independently selected from the group consisting of halogens, C1-C6 alkyl groups, and C1-C6 alkoxy(sulfo) groups, and the biheterocycle contains one or two heteroatoms selected from N, O, and S as ring members.

[0111] In this invention, the prefix "C" n -C m "In each case, it indicates that the group contains nm of carbon atoms."

[0112] "Halogen" refers to fluorine, chlorine, bromine, and iodine. In this invention, halogens are preferably fluorine, chlorine, bromine, or combinations thereof.

[0113] The term "C" used in this article n -C m "Alkyl" refers to a straight-chain or branched saturated hydrocarbon group having 1-16, 1-12, 1-8, 1-4, or 2, 4, 6, 8, 10, 12, or 14 carbon atoms, such as methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, tert-butyl, 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, n-dodecyl and n-hexadecyl and their isomers, etc.

[0114] The term "C6-C" is used in this article. m "Aryl" refers to a monocyclic or bicyclic aromatic hydrocarbon group containing 6-m carbon atoms, such as 6-10 carbon atoms, including phenyl, tolyl, ethylphenyl, propanylphenyl, butylphenyl, xylyl, methylethylphenyl, diethylphenyl, methylpropylphenyl, naphthyl and its isomers.

[0115] The term "C3-C" is used in this article. m"Cycloalkyl" refers to a saturated alicyclic monocyclic group having 3-m ring carbon atoms, such as 3-10, 3-8, 3-7, 4-8, 4-7, 5-8, 5-7 or 4, 5, 6, 7, 8 or 9 ring carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and their isomers.

[0116] The term "C3-C" m cycloalkyl-C n -C m "alkyl" indicates that it is formed by C3-C m Cycloalkyl-substituted C n -C m Alkyl groups, where the two m's can be the same or different, and C' ... n -C m Alkyl and C3-C m Cycloalkyl groups are defined as used herein. C3-C m cycloalkyl-C n -C m Alkyl groups can be C3-C6 cycloalkyl or C1-C4 alkyl groups, such as cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclopropylbutyl, cyclobutylmethyl, cyclobutylethyl, cyclobutylpropyl, cyclobutylbutyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylpropyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylpropyl, cyclohexylbutyl and their isomers, etc.

[0117] The term "C" used in this article n -C m "Alkoxy(sulfo) group" includes "C n -C m "alkoxy" and "C" n -C m "Alkylthio" refers to a group with a C-position of 10 ... n -C m alkyl corresponding to open chain C n -C m In alkanes, any carbon atom is bonded with either an oxygen atom or a sulfur atom as a linking group. n -C m Alkyl group. C n -C m C in alkoxy (sulfur) group n -C m Alkyl groups are defined as used herein. C1-C6 alkoxy(thio) groups include, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, 2-butoxy, tert-butoxy, pentoxy, isopentoxy, hexoxy, and their isomers. C1-C8 alkoxythio groups can be methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, 2-butylthio, tert-butylthio, pentoxy, isopentoxy, hexylthio, and their isomers.

[0118] The term "single or double C" is used in this article. n -C m "alkylamino" refers to an amino group consisting of one or two carbon atoms. n -C m Alkyl-substituted amino groups, wherein C n -C m Alkyl groups are defined as used herein.

[0119] In one implementation, R1 is H, a linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are unsubstituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups. Of course, the groups defined in R1 may be unsubstituented.

[0120] In one implementation, R1 is H, a linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0121] In one implementation, R1 is H, a linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0122] In one implementation, R1 is H or a linear or branched C1-C. 12 alkyl.

[0123] In one implementation, R2 is H, a linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16Alkoxy(thio) group; wherein the aforementioned groups other than H are unsubstituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups. Of course, the groups defined in R2 may be unsubstituented.

[0124] In one implementation, R2 is H, a linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0125] In one implementation, R2 is H, a linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl, mono- or di-C1-C4 alkylamino or C1-C 12 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0126] In one implementation, R2 is H, a linear or branched C1-C 12 Alkyl, mono- or di-C1-C4 alkylamino or C1-C 16 Alkoxy(thio) group. In one embodiment, R2 is H, linear or branched C1-C. 12 Alkyl, diC1-C4 alkylamino or C1-C 16 Alkoxy(sulfur) group.

[0127] In one implementation, R3 is H, a linear or branched C1-C 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are unsubstituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups. Of course, the groups defined in R3 may be unsubstituented.

[0128] In one implementation, R3 is H, a linear or branched C1-C 16 Alkyl, C3-C10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0129] In one implementation, R3 is H, a linear or branched C1-C 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0130] In one implementation, R3 is H, a linear or branched C1-C 12 Alkyl or C1-C 16 Alkoxy(sulfur) group.

[0131] In one implementation, R4 is H, a linear or branched C1-C. 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl, mono- or di-C1-C6 alkylamino or C1-C 16 Alkoxy(thio) group; wherein the aforementioned groups other than H are unsubstituted or contain one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups. Of course, the groups defined in R4 may be unsubstituented.

[0132] In one implementation, R4 is H, a linear or branched C1-C. 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C1-C 16 Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0133] In one implementation, R4 is H, a linear or branched C1-C. 12 Alkyl, C5-C7 cycloalkyl, C5-C7 cycloalkyl-C1-C 12 Alkyl or C1-C 16Alkoxy(thio) group; wherein each of the aforementioned groups other than H is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups.

[0134] In one implementation, R4 is H, a linear or branched C1-C. 12 Alkyl or C1-C 16 Alkoxy(sulfur) group.

[0135] In one implementation, R5 is H, linear, or branched C1-C. 16 Alkyl, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl-C1-C 16 Alkyl or C6-C 10 Aryl; wherein the aforementioned groups other than H are unsubstituted or contain one or more substituents independently selected from the group consisting of halogens, C1-C6 alkyl groups, and C1-C6 alkoxy(thio) groups. Of course, the groups defined in R5 may be unsubstituented.

[0136] In one implementation, R5 is H or a linear or branched C1-C. 16 Alkyl group. In one embodiment, R5 is H or a straight-chain or branched C1-C group. 12 Alkyl group. In one embodiment, R5 is H.

[0137] In one embodiment, R1 and R2, R2 and R3, or R3 and R4 together with their bonded carbon atoms form a 5, 6, or 7 partially unsaturated or aromatic carbocyclic or heterocyclic ring fused to the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members.

[0138] In one embodiment, R1 and R2, R2 and R3, or R3 and R4 together with their bonded carbon atoms form a 5, 6, or 7 partially unsaturated carbocyclic or heterocyclic ring fused to the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members.

[0139] In one embodiment, R1 and R2, R2 and R3, or R3 and R4 together with their bonded carbon atoms form a 5, 6, or 7 partially unsaturated carbocyclic or heterocyclic ring fused to the benzene ring in the coumarin structure, wherein the carbocyclic or heterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the heterocyclic ring contains one N heteroatom as a ring member.

[0140] According to the present invention, the partially unsaturated carbon rings or heterocycles mentioned in the definition of "R1 and R2, R2 and R3, or R3 and R4" no longer contain unsaturated carbon atoms as ring members except for the partially benzene ring structure fused with them.

[0141] In one embodiment, R1, R2, and R3, or R2, R3, and R4 (preferably R1, R2, and R3), together with their bonded carbon atoms, form an 8, 9, or 10-member partially unsaturated or aromatic bicarbonate ring or biheterocycle fused to the benzene ring in the coumarin structure, wherein the bicarbonate ring or biheterocycle is unsubstituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the biheterocycle contains one or two heteroatoms selected from N, O, and S as ring members.

[0142] In one embodiment, R1, R2, and R3, or R2, R3, and R4 (preferably R1, R2, and R3), together with their bonded carbon atoms, form an 8, 9, or 10-member partially unsaturated bicarbonyl ring or biheterocyclic ring fused to the benzene ring in the coumarin structure, wherein the bicarbonyl ring or biheterocyclic ring is not substituted or contains one or more substituents independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy(thio) groups, and the biheterocyclic ring contains one or two heteroatoms selected from N, O, and S as ring members.

[0143] In one embodiment, R1, R2, and R3, or R2, R3, and R4 (preferably R1, R2, and R3), together with their bonded carbon atoms, form an 8, 9, or 10-member partially unsaturated biheterocycle fused to the benzene ring in the coumarin structure, wherein the biheterocycle is unsubstituted or contains one or more substituents independently selected from the group consisting of C1-C4 alkyl groups, the biheterocycle containing one N heteroatom as a ring member, preferably the N heteroatom being a shared atom of the biheterocycle; more preferably, the biheterocycle has the structure of formula (a):

[0144]

[0145] in

[0146] * indicates the position where the coumarin structure is fused with the benzene ring; and

[0147] The structure shown in formula (a) is not substituted or contains one or more (e.g., 1-8, 1-6, or 2-6) C1-C4 alkyl groups (e.g., methyl or ethyl) as substituents.

[0148] According to the present invention, the partially unsaturated bicarbonate rings or biheterocycles mentioned in the definition of "R1, R2 and R3, or R2, R3 and R4" no longer contain unsaturated carbon atoms as ring members except for the partially benzene ring structure fused with them.

[0149] In one embodiment, at least one of R1, R2, R3, and R4 is not H, and R5 is H. In one embodiment, one, two, or three of R1-R4 are H, preferably two or three, and R5 is H. In one embodiment, R1 is H or a linear or branched C1-C. 12 Alkyl group, preferably H or straight-chain or branched C1-C6 alkyl group; R2 is H, straight-chain or branched C1-C6 alkyl group. 12 Alkyl, diC1-C4 alkylamino or C1-C 16 Alkoxy (sulfur) group; preferably H, straight-chain or branched C1-C6 alkyl, diC1-C4 alkylamino or C1-C 14 alkoxy(sulfo) group; R3 is H, straight-chain or branched C1-C 12 Alkyl or C1-C 16 Alkoxy (sulfur) group, preferably H, straight-chain or branched C1-C6 alkyl or C1-C 14 alkoxy(sulfo) group; R4 is H, straight-chain or branched C1-C 12 Alkyl or C1-C 16 Alkoxy (sulfur) group, preferably H, straight-chain or branched C1-C6 alkyl or C1-C 14 An alkoxy(thio) group; and R5 is H; or R1, R2, and R3 together with their bonded carbon atoms form an 8, 9, or 10-member (preferably 8 or 10-member) partially unsaturated biheterocycle fused to the benzene ring in the coumarin structure, wherein the biheterocycle is unsubstituted or contains one or more substituents independently selected from the group consisting of C1-C4 alkyl groups, the biheterocycle containing one N heteroatom as a ring member, preferably the N heteroatom being a shared atom of the biheterocycle; more preferably the biheterocycle has the structure of formula (a): Wherein * indicates the position fused with the benzene ring in the coumarin structure; and the structure shown in formula (a) is not substituted or contains one or more C1-C4 alkyl groups as substituents; preferably at least one of R1, R2, R3, and R4 is not H, for example, one, two, or three of R1-R4 are H, preferably two or three are H. In one embodiment, the nitrogen atom (if present) on the heterocycle or biheterocycle of the present invention does not contain a hydrogen atom.

[0150] In one embodiment, the 3-formyl coumarin compound of formula (I) has the structure shown in formula (I-1):

[0151]

[0152] R4 and R5 are defined as above;

[0153] Rx and Ry are independently selected from C1-C6 alkyl and C1-C6 alkoxy(thio) groups, preferably C1-C6 alkyl, more preferably C1-C4 alkyl; and

[0154] a and b are independent values ​​of 0-6, with 0, 1, 2, 3 or 4 being preferred.

[0155] In the structure shown in equation (I-1), R1, R2 and R3 form the double heterocycle of equation (a).

[0156] In one embodiment, the 3-formylcoumarin compound of formula (I) is selected from the group consisting of:

[0157]

[0158]

[0159] Method for preparing 3-formylcoumarin compound of formula (I)

[0160] One aspect of the present invention provides a method for preparing the 3-formylcoumarin compound of formula (I) of the present invention, comprising the following steps:

[0161] (1) Knoevenagel condensation: Compound (II) is subjected to a Knoevenagel condensation reaction with a C1-C6 alkyl ester of acetoacetic acid to obtain compound (III):

[0162]

[0163] (2) Oxidation reaction: The compound of formula (III) is oxidized with an oxidizing agent to obtain the compound of formula (I).

[0164]

[0165] In the above formulas, R1, R2, R3, R4 and R5 are defined as above.

[0166] According to the present invention, starting from the compound of formula (II), a Knauvengel condensation reaction is first carried out to obtain the 3-acetylcoumarin compound of formula (III), and then an oxidation reaction is carried out to prepare the 3-formylcoumarin compound of formula (I).

[0167] Step (1) Kneven-Gail condensation reaction

[0168] Compound (II) is subjected to a Knauvengel condensation reaction with a C1-C6 alkyl ester of acetoacetic acid to give compound (III):

[0169]

[0170] R1, R2, R3, R4 and R5 are defined as above.

[0171] According to the present invention, the compound of formula (II) has a benzene ring structure containing adjacent -C(=O)R5 and a hydroxyl group, and can be synthesized into a coumarin ring via a Knauvengel condensation reaction. Specifically, in this reaction, -C(=O)R5 preferably undergoes condensation with a C1-C6 alkyl ester of acetoacetic acid under the action of a catalyst, dehydrating to form a carbon-carbon double bond, and the hydroxyl group undergoes an exchange reaction with the ester bond of the C1-C6 alkyl ester of acetoacetic acid, removing the corresponding alcohol to form a new ester bond, thereby forming a coumarin ring, thus obtaining the compound of formula (III).

[0172] To accelerate the Knauvengay condensation reaction, the above reaction is usually carried out in the presence of a catalyst suitable for the Knauvengay condensation reaction. As catalysts, amines such as primary, secondary, and tertiary amines and their corresponding ammonium salts are commonly used, preferably piperidine; inorganic bases such as alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal carbonates, and alkali metal or alkaline earth metal bicarbonates; inorganic salts such as potassium fluoride, aluminum phosphate, and diammonium hydrogen phosphate; and Lewis acid and tertiary amine complexes such as TiCl4 / piperidine or TiCl4 / triethylamine. The amount of catalyst used, based on the compound of formula (II), can be 1-20% by weight, or 2-15% by weight, or 3-15% by weight.

[0173] The above-described Knauvengael condensation reaction is typically carried out in a solvent, preferably an organic solvent, and more preferably a protic solvent. There are no particular restrictions on the type of solvent, as long as it can dissolve the compound of formula (II) with the C1-C6 alkyl acetoacetic acid and is chemically inert to the Knauvengael condensation reaction, i.e., it does not participate in the reaction. Suitable solvents include, for example, alcohols (such as ethanol), ethers (such as diethyl ether), ketones (such as acetone), aromatic hydrocarbons (such as toluene), dimethyl sulfoxide, or N,N-dimethylformamide, with alcohols such as ethanol being preferred.

[0174] An example of a C1-C6 alkyl acetoacetate is ethyl acetoacetate.

[0175] The molar ratio of the compound of formula (II) to the C1-C6 alkyl ester of acetoacetic acid is 1:0.1-1:10 (e.g., 1:0.2, 1:0.3, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:3, 1:4, 1:5 or 1:8), preferably 1:0.3-1:5, more preferably 1:0.9-1:3 or 1:1.1-1:3.

[0176] The temperature range for the Knauvengel condensation reaction is typically 40-120°C, preferably 60-90°C. There are no particular limitations on the reaction time, which is usually 2-20 hours or 3-15 hours, preferably 3-10 hours or 3-6 hours.

[0177] After the Knauvengel condensation reaction is complete, the crude product of compound (III) is obtained. If further purification of compound (III) is desired, the compound can be further purified, for example by recrystallization. The choice of recrystallization solvent is conventional and not particularly limited. According to the invention, it is advantageous to recrystallize the crude product of compound (III) using an alcohol (such as ethanol).

[0178] Step (2) Oxidation reaction

[0179] Compound (III) is oxidized with an oxidizing agent to obtain compound (I).

[0180]

[0181] R1, R2, R3, R4 and R5 are defined as above.

[0182] The oxidant can be selected from selenium dioxide and acidic peroxides, such as acidic hydrogen peroxide and acidic alkali metal peroxides.

[0183] This oxidation reaction is typically carried out in an organic solvent, preferably a polar organic solvent. Suitable solvents include, for example, pyridine, piperidine, and triethylamine.

[0184] The molar ratio of the compound of formula (III) to the oxidant can be 1:1 to 1:5 (e.g., 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.5, 1:3 or 1:4), preferably 1:1.5 to 1:3.

[0185] The temperature range for the above oxidation reaction is typically 30-200°C, preferably 40-150°C (e.g., 50°C, 60°C, 80°C, 100°C, 150°C, or 180°C). The oxidation reaction time can be 0.1-10 hours, preferably 0.3-5 hours.

[0186] According to the present invention, the reaction process can be monitored during the oxidation reaction. In one embodiment, the reaction is stopped when impurities are detected during the oxidation reaction. The monitoring can be performed using a spot test tube. After the reaction is complete, the reactants can be treated with hydrochloric acid.

[0187] The 3-formylcoumarin compound of formula (I) of this invention exhibits strong absorption in the wavelength range of 300-550 nm, particularly in the range of 365-475 nm. Therefore, it can be used as a photoinitiator in UV-VIS LED light source curing systems, especially suitable for long-wavelength UV-VIS LED light source curing. Moreover, the compound of formula (I) of this invention is safe and non-toxic, and compared with traditional photoinitiators, it reduces the harm to human health and the environment, and can also be used in fields such as food packaging.

[0188] Use of the compounds of this invention as photoinitiators

[0189] One aspect of the present invention provides the use of the 3-formylcoumarin compound of formula (I) of the present invention as a photoinitiator, such as a cleavage-type photoinitiator or a hydrogen-abstracting photoinitiator.

[0190] The 3-formylcoumarin compound of formula (I) of the present invention can be used as a photoinitiator in UV-VIS LED light source curing systems, especially in light source curing systems with radiation wavelengths of 300-550 nm, particularly 365-475 nm.

[0191] The 3-formylcoumarin compound of formula (I) of the present invention can be used as a pyrolysis photoinitiator in UV-VIS LED light source curing systems, especially in light source curing systems with radiation wavelengths of 300-550 nm, particularly 365-475 nm.

[0192] The 3-formylcoumarin compound of (I) of the present invention can also be used as a hydrogen-abstracting photoinitiator in UV-VIS LED light source curing systems, especially in light source curing systems with radiation wavelengths of 300-550 nm, particularly 365-475 nm.

[0193] According to the present invention, the 3-formylcoumarin compound of formula (I) can be used in combination with a compound selected from tertiary amine compounds (such as ethyl 4-dimethylaminobenzoate, i.e., EDB), α-amino acid compounds, or thiols. According to the present invention, these compounds act as hydrogen donors, and the 3-formylcoumarin compound here acts as a hydrogen-abstracting photoinitiator in conjunction with the hydrogen donor such as EDB to initiate a free radical polymerization reaction.

[0194] One aspect of the present invention provides the use of the 3-formylcarboxylic acid coumarin compound of formula (I) as a photoinitiator-sensitized onium salt, particularly in UV-VIS LED light source curing systems, especially in light source curing systems with radiation wavelengths of 300-550 nm, particularly 365-475 nm. In this aspect, the 3-formylcarboxylic acid coumarin compound of formula (I) may also be referred to as a photosensitizer.

[0195] The onium salt may be selected from iodonium salts and thionium salts.

[0196] The iodonium salts and thionium salts respectively have the following general formulas (A) and (B).

[0197]

[0198] in

[0199] R a R b R c R d R e Each is an unreplaced C6-C. 10 aryl, or selected from halogen, nitro, carbonyl, C1-C 12 Alkyl, C1-C 12 Alkoxy, phenylthio, phenyl, and substituted phenyl groups substituted at C6-C 10 The aryl group, preferably phenyl or naphthyl, or a phenyl or naphthyl group substituted with a substituent selected from halogens, nitro groups, C1-C6 alkyl groups, and substituted phenyl groups, wherein the substituted phenyl group comprises one or more substituents selected from halogens, nitro groups, C1-C6 alkyl groups, and C1-C6 alkoxy groups; and

[0200] Y and Z are non-nucleophilic anions, such as trifluoromethanesulfonate and BF4. - ClO4 - PF6 - AsF6 - SbF6 - .

[0201] Preferably, the thioonium salt is selected from one or more of the following groups: mixed thioonium hexafluorophosphate (GR-SS058), 4-(phenylthio)phenyl·diphenylthioonium hexafluorophosphate, 4-(phenylthio)phenyl·diphenylthioonium hexafluoroantimonate (GRSS059), diphenyl-(4-phenylthio)phenylthioonium hexafluoroantimonate (GRSS059B), and mixed thioonium hexafluoroantimonate (GR-SS061).

[0202] Preferably, the iodonium salt is selected from one or more of the following group: diphenyl iodonium hexafluorophosphate (810), 4-isobutylphenyl-4'-tolyl iodonium hexafluorophosphate (GR-IS051), bis(4-dodecylbenzene)iodonium hexafluoroantimonate (GR-IS052), bis(4-dodecylbenzene)iodonium hexafluorophosphate (GR-IS052B), (4-octyloxyphenyl)benzene iodonium hexafluoroantimonate (GR-IS053), bis(4-tert-butylbenzene)iodonium hexafluorophosphate (GR-IS054), bis(4-tert-butylbenzene)iodonium hexafluoroantimonate (GR-IS225), 4,4'-xylyl iodonium hexafluorophosphate, and 4,4'-xylyl iodonium hexafluoroantimonate.

[0203] In one embodiment, the iodonium salt is a diaryliodonium salt, preferably a diphenyliodonium salt. The thiodonium salt is a triarylthiodonium salt, preferably a triphenylthiodonium salt.

[0204] The onium salt sensitized by the 3-formylcoumarin compound of formula (I) can be used to initiate free radical photopolymerization, or to initiate cationic photopolymerization, or to initiate free radical-cationic hybrid photopolymerization.

[0205] Photoinitiator Composition

[0206] The present invention also relates to a photoinitiator composition comprising a 3-formylcoumarin compound of formula (I) of the present invention.

[0207] In one embodiment, the composition comprises a 3-formylcoumarin compound of formula (I) and a compound selected from tertiary amine compounds, α-amino acid compounds, or thiols. As described above, these compounds act as hydrogen donors. The weight ratio of the 3-formylcoumarin compound of formula (I) to the compound selected from tertiary amine compounds, α-amino acid compounds, or thiols can be 10:1 to 1:10 (e.g., 8:1, 5:1, 2:1, 1:1, 1:2, 1:5, 1:8), preferably 5:1 to 1:5, more preferably 2:1 to 1:2.

[0208] In one embodiment, the composition comprises a 3-formylcoumarin compound of formula (I) with an onium salt. The onium salt may be selected from iodonium salts and thionium salts, particularly iodonium salts and thionium salts as described above.

[0209] The weight ratio of the 3-formylcoumarin compound of formula (I) to the onium salt can be 10:1 to 1:100 (e.g., 8:1, 5:1, 2:1, 1:1, 1:2, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:80), preferably 5:1 to 1:80, more preferably 1:1 to 1:50 or 1:2 to 1:50.

[0210] The 3-formylcarboxylic acid coumarin of formula (I) of the present invention can be used as a photoinitiator in UV-VIS LED photocuring technology. The 3-formylcarboxylic acid coumarin compound of formula (I) of the present invention can also be used as a photoinitiator in coatings, inks, microelectronics, printing, and other fields. When the 3-formylcarboxylic acid coumarin compound of formula (I) of the present invention is used as a photoinitiator, its dosage is as described below for photocurable compositions.

[0211] Photocurable Composition

[0212] The present invention also relates to photocurable compositions comprising at least one 3-formylcoumarin compound of formula (I) of the present invention or a photoinitiator composition of the present invention.

[0213] In the photocurable composition, the amount of the 3-formylcoumarin compound of formula (I) of the present invention or the photoinitiator composition of the present invention is generally 0.001-10% by weight (e.g., 0.005% by weight, 0.01% by weight, 0.05% by weight, 0.1% by weight, 0.2% by weight, 0.5% by weight, 1% by weight, 2% by weight, 5% by weight or 8% by weight), preferably 0.1-6% by weight, such as 0.2-5% by weight, based on the amount of active ingredient in the photocurable composition.

[0214] In the context of this disclosure, active ingredient refers to the component in a photocurable composition other than the solvent.

[0215] In addition to the photoinitiator of the present invention, the photocurable composition also comprises a photopolymerizable component, such as a photocurable resin. The photocurable resin may be a free radical photocurable resin and / or a cationic photocurable resin.

[0216] In this invention, the photocurable resin has photocurable reactive groups, such as unsaturated carbon-carbon double bonds and / or epoxy groups. For example, the photocurable resin can be an oligomer or prepolymer containing unsaturated carbon-carbon double bonds and / or epoxy groups. Upon exposure to light, this oligomer or prepolymer can undergo a polymerization reaction initiated by a photoinitiator, leading to cross-linking and curing. The photocurable resin is a major component of photocurable products (e.g., UV coatings, UV inks, UV adhesives, etc.).

[0217] As photocurable resins (free radical photocurable resins) containing unsaturated carbon-carbon double bonds, examples include epoxy (meth)acrylate resins, polyester (meth)acrylates, polyether (meth)acrylates, polyurethane (meth)acrylates, olefinically unsaturated polyesters, amino (meth)acrylate resins, and photo-imaging alkali-soluble resins. According to the present invention, it is advantageous to use epoxy (meth)acrylate resins, polyester (meth)acrylates, polyether (meth)acrylates, polyurethane (meth)acrylates, or combinations thereof.

[0218] The preferred epoxy (meth)acrylate resins are bisphenol A epoxy (meth)acrylate, bisphenol A epoxy acrylate diluted with tripropylene glycol dimethacrylate, or combinations thereof, such as bisphenol A epoxy acrylate WSR-U125 from Wuxi Resin Factory, bisphenol A epoxy acrylate 621A-80 diluted with 20% tripropylene glycol diacrylate from Chang Hsing Chemical Co., Ltd. in Taiwan, modified bisphenol A epoxy acrylate 623-100 from Chang Hsing Chemical Co., Ltd. in Taiwan, and modified bisphenol A epoxy acrylate 6231A-80 diluted with 20% tripropylene glycol diacrylate from Chang Hsing Chemical Co., Ltd. in Taiwan.

[0219] The preferred polyester (meth)acrylates are highly functional hyperbranched polyester acrylate resins, especially those with a functionality of 5-30, such as hyperbranched polyester acrylate prepolymers with a functionality of 6-20. Examples include Wuxi Knox's hyperbranched polyester acrylate prepolymer 932-100 (6 functionality) and Sartoma's hyperbranched polyester acrylate prepolymers CN2300 (8 functionality), CN2301 (9 functionality), and CN2302 (16 functionality).

[0220] The polyether (meth)acrylate can be polyethylene oxide (meth)acrylate, polypropylene oxide (meth)acrylate, polyethylene oxide-propylene oxide (meth)acrylate, or a combination thereof. An example is PEG(400) diacrylate.

[0221] Polyurethane (meth)acrylates are preferably aliphatic polyurethane acrylates. Examples include aliphatic polyurethane hexaacrylates 6145-100 and 6161-100 from Chang Hsing Chemical Co., Ltd. in Taiwan; aliphatic polyurethane diacrylate 611B-85 diluted with 15% 1,6-hexanediol diacrylate (HDDA); polyester polyol acrylic resin diluted with 20% ethoxytrimethylolpropane triacrylate; aliphatic polyurethane diacrylate 6141H-80; aliphatic polyurethane acrylate CN9013 (9 functionalities) from Sartoma Chemical Co., Ltd. in the United States; aliphatic polyurethane acrylate CN966B85 (2 functionalities) diluted with 15% 1,6-hexanediol diacrylate (HDDA) from Sartoma Chemical Co., Ltd. in the United States; and aliphatic polyurethane acrylate CN962 (2 functionalities).

[0222] The amount of photocurable resin in the photocurable composition is typically 10-90% by weight, preferably 55-80% by weight, based on the amount of active ingredient in the photocurable composition. In the context of this disclosure, active ingredient refers to the component in the photocurable composition other than the solvent.

[0223] The photocurable composition may further include a multifunctional active diluent.

[0224] In this invention, a multifunctional reactive diluent refers to a monomer containing two or more photopolymerizable groups. Multifunctional reactive diluents have low viscosity and strong dissolving power. After being irradiated by a light source, multifunctional reactive diluents can be polymerized by active free radicals to form a cross-linked network structure.

[0225] According to the present invention, the preferred multifunctional reactive diluent is a multifunctional (meth)acrylate reactive diluent. This refers to a monomer containing two or more polymerizable (meth)acrylate groups. Examples of multifunctional (meth)acrylate reactive diluents include trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate (PETTA), propoxylated trimethylolpropane triacrylate (PO-TMPTA), or ethoxylated trimethylolpropane triacrylate (EO-TMPTA), pentaerythritol triacrylate (PETA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPEPA), dipentaerythritol hexaacrylate (DPHA), diol diacrylates such as tripropylene glycol diacrylate (TPGDA), 1,6-hexanediol diacrylate (HDDA), triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, glycerol diacrylate, and urethane dimethacrylate (UDMA), etc.

[0226] The amount of the multifunctional active diluent in the photocurable composition is typically 8-60% by weight, preferably 15-45% by weight, based on the amount of active ingredient in the photocurable composition.

[0227] According to the present invention, the photocurable composition may further comprise a monofunctional active diluent.

[0228] In this invention, a monofunctional reactive diluent refers to a monomer containing a photopolymerizable group. It has low viscosity, strong dissolving power, and can act as a partial organic solvent. After being irradiated by a light source, this monofunctional reactive diluent can be polymerized by active free radicals. Monofunctional reactive diluents mainly include (meth)acrylate compounds and vinyl compounds. Examples of (meth)acrylate monofunctional reactive diluents include methyl methacrylate (MMA), n-butyl acrylate (BA), isooctyl acrylate (2-EHA), isodecyl acrylate (IDA), lauryl acrylate (LA), hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and some (meth)acrylates with cyclic structures. Additionally, examples of vinyl monofunctional reactive diluents include styrene (St), vinyl acetate (VA), and N-vinylpyrrolidone (NVP).

[0229] The amount of monofunctional reactive diluent in a photocurable composition is typically 5-50% by weight, preferably 8-40% by weight, based on the amount of active ingredient in the photocurable composition.

[0230] In one embodiment of the invention, the photocurable composition may be free of reactive diluents, such as polyfunctional reactive diluents and monofunctional reactive diluents.

[0231] The photocurable composition of the present invention may optionally contain an organic solvent. The choice of organic solvent is conventional. Examples of organic solvents include aromatic hydrocarbons such as benzene and toluene, halogenated alkanes such as chloroform, dichloromethane, and chloroethane, ketones such as acetone, butanone, and pentanone, alcohols such as methanol, ethanol, propanol, isopropanol, and ethylene glycol, and ethylene glycol ethers, ethylene glycol ether acetates, propylene glycol ethers, and propylene glycol ether acetates. In one embodiment, the photocurable composition may be solvent-free.

[0232] In one embodiment of the invention, the photocurable composition may be free of organic solvents.

[0233] The photocurable composition of the present invention may optionally include other additives, such as leveling agents, antioxidants, antisettling agents, colorants, microbial agents, such as antibacterial agents, and thermal insulation material additives. In a preferred embodiment of the invention, the leveling agent is selected from Yoka Chemicals. FLOW series leveling agents, with 360S, 372S, 384S, 392S, 400U, and 415U being particularly preferred.

[0234] The preparation of the photocurable composition of the present invention is conventional; for example, each component of the photocurable composition of the present invention can be uniformly mixed together.

[0235] Furthermore, the present invention relates to a photocurable composition based on a cationic photopolymerization mechanism comprising the 3-formylcoumarin compound of formula (I) of the present invention. In addition to the 3-formylcoumarin compound of the present invention, the photocurable composition of the present invention also comprises an onium salt co-initiator and a photocurable resin (cationic photocurable resin). The onium salt can be referred to the specific description above.

[0236] In this invention, onium salt co-initiators can generate conjugated acids under the sensitization of 3-formylcoumarin compounds, initiating cationic photopolymerization reactions of alkenyl ether compounds, ethylene oxide compounds, and oxetane compounds. The alkenyl ether compounds, ethylene oxide compounds, and oxetane compounds can be in monomer or resin form (including oligomers or prepolymers).

[0237] As a photocurable resin (cationic photocurable resin), it can include alkenyl ether compounds, oligomers or prepolymers containing ethylene oxide, propylene oxide, or oxetane functional groups. When exposed to light, this oligomer or prepolymer can undergo a polymerization reaction initiated by a photoinitiator, leading to cross-linking and curing. Photocurable resins are the main component of photocurable products (such as UV coatings, UV inks, UV adhesives, etc.).

[0238] In this invention, the alkenyl ether compound can be a C1-C6 alkenyl ether compound, such as vinyl ethers, 1-propenyl ethers, 1-butenyl ethers, 1-pentenyl ether compounds, etc., preferably vinyl ether compounds. The alkenyl ether compound is, for example, an alkenyl ether starting from a monohydric alcohol having 1-12, preferably 1-6 carbon atoms, a dihydric alcohol having 2-12, preferably 2-8 carbon atoms, a trihydric alcohol or more having 3-12, preferably 3-6 carbon atoms, particularly a C1-C6 alkenyl ether. Polymers containing alkenyl ether functional groups, such as vinyl ethers, may also be mentioned as alkenyl ether compounds. Specific examples may include one or more of the following: triethylene glycol divinyl ether, isobutyl vinyl ether, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether (BVE), hydroxyethyl vinyl ether, diethylene glycol divinyl ether (DEGDVE), triethylene glycol divinyl ether (TEGDVE), vinyl n-octyl ether, divinyl-1,4-butanediol ether, 2-ethylhexyl vinyl ether, 1,4-cyclohexyldiethanol divinyl ether, 4-hydroxybutyl vinyl ether (HBVE), triethylene glycol divinyl ether (DVE-3), glycerol carbonate vinyl ether, and dodecyl vinyl ether. Furthermore, compounds having both vinyl ether and (meth)acrylate alkyl ester structures may also be mentioned, and these compounds may be used simultaneously with one or more of them. The alkenyl compounds also include carbamates containing one or more, such as 1-3 alkenyl ether structures. The carbamates containing alkenyl ether structures can be obtained by reacting alkenyl ethers with hydroxyl groups with isocyanate compounds (such as polyisocyanate compounds). Examples include diethyleneoxyalkyl carbamates and trifunctional vinyl ethers prepared from 1,6-hexamethylenediisocyanate trimers and 4-hydroxyvinyl ethers.

[0239] According to the present invention, examples of the oxetane compounds may include 3,3'-(oxybis(methylene)bis(3-ethyl)oxetane, 3-ethyl-3-oxetane methanol, bis[(3-methyl-3-oxetane-butylmethoxy)methyl] ether, bis[(3-ethyl-3-oxetane-butylmethoxy)methyl] ether, 1,4-bis[(3-methyl-3-oxetane-butylmethoxy)methyl]benzene, 1,4-bis[(3-methyl-3-oxetane-butylmethoxy)methyl]benzene, etc. [3-Oxetane-3-oxetane-3-oxetane]benzene, methyl acrylate (3-methyl-3-oxetane), methyl acrylate (3-ethyl-3-oxetane), methyl methacrylate (3-methyl-3-oxetane), methyl methacrylate (3-ethyl-3-oxetane), 3-methyl-3-ethylenehydroxymethyloxetane, 3-methyl-3-ethylenehydroxypolyethoxylated methyloxetane, 1,4-bis(3- Ethyl-3-oxetane(methoxy)butane, 1,6-bis(3-ethyl-3-oxetane(methoxy)hexane, pentaerythritol tris(3-ethyl-3-oxetane(methyl) ether, 3-methyl-3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 1,3-bis[(3-ethyl-3-oxetane(methoxy)methyl]propane, polyethylene glycol bis(3-ethyl-3-oxetane)butane 3-ethyl-3-oxetane methyl (3-ethyl-3-oxetane methyl) ether, ethylene glycol bis(3-ethyl-3-oxetane methyl) ether, tricyclodecanedimethyldimethylene (3-ethyl-3-oxetane methyl) ether, trimethylolpropane tri(3-ethyl-3-oxetane methyl) ether, pentaerythritol tetra(3-ethyl-3-oxetane methyl) ether, 3-epoxyethylene 7-oxetane [4.1].[0] Heptane, and 3-ethyl-3-oxabutane methanol (GR-OXT-01), 3-ethyl-3-chloromethyloxabutane (GR-OXT-02), 3,3'-(oxybismethylene)bis(3-ethyl)oxabutane GR-OXT-03, 3-ethyl-3-(2-ethylhexyloxymethyl)oxabutane (GR-OXT-04), 3,3'-((((propane-2,2-diylbis(4,1-phenylene))bis(oxy))bis(methylene))bis(3-ethyloxabutane)(GR-OXT-05), 3-ethyl-3-(benzyloxymethyl)oxabutane produced by Gurun Technology. This includes polyfunctional oxetane compounds such as oligomers or copolymers of one or more of the following: oxetane (GR-OXT-06), oxetane methacrylate (GR-OXT-09), and bis[(3-ethyloxetane-3-yl)methyl]benzene-1,4-dicarboxylic acid ester (GR-OXT-11); oxetane alcohols and etherified resins containing hydroxyl groups, such as phenolic varnish resins, poly(p-hydroxystyrene), Cardo-type bisphenols, calixarenes, resorcinol calixarenes, or silsesquioxanes. Compounds possessing both oxetane and alkyl (meth)acrylate structures can also be cited.

[0240] The ethylene oxide compounds may be selected, for example, from glycidyl ether epoxy compounds, glycidyl ester epoxy compounds, glycidyl amine epoxy compounds, aliphatic epoxy compounds, alicyclic epoxy compounds, etc. Ethylene oxide compounds may be in the form of monomers or resins (such as oligomers or prepolymers). Compounds simultaneously having an ethylene oxide group and a free radical polymerizable group (such as an acrylate group) may also be mentioned, such as epoxy (meth)acrylate resins. Glycidyl ether epoxy compounds (especially aliphatic glycidyl ether epoxy compounds, bisphenol A type glycerol ether epoxy compounds) and aliphatic epoxy resins are preferred. Furthermore, compounds simultaneously having an ethylene oxide group (such as an alicyclic ethylene oxide or glycidyl ether group) and a (meth)acrylate alkyl ester structure are preferred.

[0241] Examples of these ethylene oxide compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate (6110), bis(3,4-epoxycyclohexylmethyl adipic acid) (UVR-6128), trimethylolpropane glycidyl ether (TPEG), 1,2-epoxy-4-vinylcyclohexane, methyl 3,4-epoxycyclohexane carboxylate, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, bisphenol A diglycidyl ether (E-03 type), 3-epoxyethylene 7-oxabicyclo[4,1,0]heptane, ethylene glycol diglycidyl ether, C 12 -C14 Alkyl glycidyl ethers, polypropylene glycol diglycidyl ethers, polyethylene glycol diglycidyl ethers, polyether polyol glycidyl ethers, glycidyl methacrylate, trimethyloltriglycidyl ether, 1,4-butanediol diglycidyl ether, and their oligomers or copolymers, as well as polyfunctional epoxy compounds such as EPIKOTE Resin 862, EPIKOTE Resin 827, EPIKOTE Resin 869, EPIKOTE Resin 320, EPIKOTE Resin 816, EPIKOTE Resin 232, EPIKOTE Resin 144, etc. These compounds can be used in one or more forms.

[0242] Furthermore, the present invention relates to a photocurable composition comprising a 3-formylcoumarin compound of formula (I) of the present invention, based on a free radical-cationic hybrid photopolymerization mechanism. In addition to the 3-formylcoumarin compound of the present invention, such photocurable compositions also comprise ononium salts and photocurable resins (free radical photocurable resin and cationic photocurable resin).

[0243] In this invention, the onium salt is preferably selected from iodonium salts and thiodonium salts, and more preferably from diaryliodonium salts and triarylthiodonium salts. A detailed description of the onium salt is provided above.

[0244] The photocurable resin is a free radical photocurable resin and a cationic photocurable resin. For details on free radical photocurable resins and cationic photocurable resins, please refer to the detailed description above.

[0245] The photocurable composition of the present invention may optionally contain an organic solvent. The choice of organic solvent is conventional. Examples of organic solvents include aromatic hydrocarbons such as benzene and toluene, halogenated alkanes such as chloroform, dichloromethane, and chloroethane, ketones such as acetone, butanone, and pentanone, alcohols such as methanol, ethanol, propanol, isopropanol, and ethylene glycol, as well as ethylene glycol ethers, ethylene glycol ether acetates, propylene glycol ethers, and propylene glycol ether acetates.

[0246] The photocurable composition of the present invention may optionally include other additives, such as leveling agents, antioxidants, antisettling agents, colorants, microbial agents, such as antibacterial agents, and thermal insulation material additives. In a preferred embodiment of the invention, the leveling agent is selected from Yoka Chemicals. FLOW series leveling agents, with 360S, 372S, 384S, 392S, 400U, and 415U being particularly preferred.

[0247] The preparation of the photocurable composition of the present invention is conventional; for example, each component of the photocurable composition of the present invention can be uniformly mixed together.

[0248] Photocurable materials and preparation methods

[0249] Another aspect of the present invention provides a curable material obtainable from the photocurable composition of the present invention. The resulting curable material can be a photocurable coating, such as a coating containing functional materials, a coating for UV and / or visible light filters; a sealant; a photolithography material; a holographic recording material; a 3D printing material; a lithographic printing material; a material for fabricating optical devices; and a material for improving mechanical properties, such as carbon fiber composites and / or inorganic nanoparticles and / or organic nanoparticles, etc.

[0250] The present invention also relates to a method for preparing a photocurable material, comprising irradiating the photocurable composition with a light source having a radiation wavelength of 300-550 nm, particularly 365-475 nm, such as a UV-VIS LED light source.

[0251] Furthermore, the compound of formula (I) disclosed in this invention has a simple production process and high yield, making it very suitable for industrial production. This type of compound exhibits good compatibility with UV-VIS LED light sources with radiation wavelengths of 300-550 nm, especially 365-475 nm, and can be widely used as a photoinitiator in fields related to UV-VIS LED photocuring, such as coatings, inks, microelectronics, printing, 3D printing, and dental materials.

[0252] Furthermore, the limited variety of photoinitiators currently available for deep curing of UV-VIS LED light sources, especially long-wavelength UV-VIS LED light sources, restricts the widespread application of UV-VIS LED light sources in the photocuring field. The 3-formylcarboxylic acid coumarin compound of formula (I) of this invention can be used for deep curing with UV-VIS LED light sources, thereby contributing to the widespread application of green and environmentally friendly UV-VIS LED light sources in the UV photocuring industry.

[0253] Example

[0254] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature or product specifications in the art.

[0255] Example 1: Preparation of Compound 1

[0256]

[0257] The synthetic route for compound 1 is as follows:

[0258]

[0259] Step (1): Synthesis of intermediate compound 1a

[0260] 4-Methyl-2-hydroxy-5-methylthiobenzaldehyde (0.05 mol, 9.10 g) was added to a 250 mL three-necked round-bottom flask containing 50 mL of ethanol. After stirring until homogeneous, piperidine (0.015 mol, 1.28 g) and ethyl acetoacetate (0.07 mol, 9.11 g) were added. The reaction mixture was then heated to reflux and stirred for 4 h. After the reaction was complete, the mixture was cooled to room temperature and filtered to obtain a yellow solid. This solid was then recrystallized from ethanol to give 11.41 g of product, with a yield of 92%, which was identified as compound 1a. ¹H-NMR (400 MHz, CDCl₃) δ 8.45 (s, 1H), 7.50 (s, 1H), 6.98 (s, 1H), 2.46 (s, 3H), 2.37 (s, 3H), 2.34 (s, 3H).

[0261] Synthesis of target product 1

[0262] Intermediate compound 1a (9.92 g, 0.04 mol), SeO2 (11.09 g, 0.1 mol), and 70 mL of pyridine were added to a 250 mL three-necked round-bottom flask. The reaction was stirred at 130 °C for 2 h, and the reaction progress was monitored by TLC. The reaction was stopped immediately when impurities were detected. The reaction solution was cooled to room temperature, filtered to remove insoluble matter, and a large amount of ethyl acetate was added to the filtrate, resulting in the precipitation of solid powder. The filter cake was filtered again, and acidified with hydrochloric acid to convert the pyridine salt of coumarin 3-formylcarboxylic acid to the corresponding carboxylic acid. The mixture was stirred at room temperature for 2 h, finally yielding 5.89 g of a yellow solid product, with a yield of 53%, which was identified as compound 1. The NMR data of compound 1 are shown in Table 1.

[0263] Example 2-14: Preparation of compound 2-14

[0264] Repeat the method of Example 1, and appropriately change the reaction raw materials to obtain compounds 2-14 in the table below and their NMR data.

[0265] Table 1

[0266]

[0267]

[0268] Characterization 1: Ultraviolet-Visible light absorption performance test:

[0269] Taking the compounds of Examples 1-3 as examples, the ultraviolet-visible light absorption properties of the compounds of the present invention were tested. The molar extinction coefficients of the compounds of Examples 1-3 in acetonitrile (50 ppm) were measured and calculated by UV-Vis spectroscopy. Figure 1 Table 2 lists the maximum absorption wavelength (λmax) and the corresponding molar extinction coefficient, as well as the molar extinction coefficient at common LED light source emission wavelengths. Figure 1 As shown in Table 2, the compounds in Examples 1-3 have good absorption in the near-UV-Vis range, which matches the common UV-Vis ultraviolet LED light source in the 300nm-500nm range.

[0270] Table 2 shows the maximum absorption wavelengths λ of the compounds in Examples 1-3. max And the corresponding molar extinction coefficient, as well as the molar extinction coefficient at common LED light source emission wavelengths.

[0271]

[0272] Characterization 2: Photoinitiation performance test:

[0273] Raw materials used:

[0274] TPGDA: Tripropylene glycol diacrylate (acrylate monomer), purchased from Shanghai Yinchang New Materials Co., Ltd.

[0275] PEG(400)DA: Polyethylene oxide diacrylate (acrylate resin), purchased from Shanghai Yinchang New Materials Co., Ltd.;

[0276] 6110: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate (epoxy monomer), purchased from Hubei Gurun Technology Co., Ltd.;

[0277] EDB: Ethyl N,N-dimethylaminobenzoate, purchased from Beijing Innocare Technology Co., Ltd.;

[0278] GR-IS054: Bis(4-tert-butylphenyl)iodonium hexafluorophosphate (iodonium salt, abbreviated as GR54), purchased from Hubei Gurun Technology Co., Ltd.;

[0279] GR-SS061: Mixed thionium hexafluoroantimonate, composed of diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate and bis(4-(diphenylsulfonium)phenyl)sulfide-bishexafluoroantimonate, purchased from Hubei Gurun Technology Co., Ltd.

[0280] Test method:

[0281] Fourier transform infrared (FTIR) and Fourier transform infrared-real-time infrared (FTIR) methods were used to test the photoinitiating properties of the compounds in the above examples as oil-based photoinitiators for the free radical polymerization of acrylate monomer (TPGDA) and the cationic polymerization of epoxy monomer (6110), and as water-based photoinitiators for the polymerization of acrylate resin (PEG(400)DA). The characteristic peaks of the acrylate and epoxy monomers were selected at 1630 cm⁻¹, respectively. -1 (carbon-carbon double bond) and 916 cm -1 (Epoxy functional group). The carbon-carbon double bond conversion rates of TPGDA and PEG(400)DA after 300 seconds of exposure are shown in Tables 3 and 4, respectively. The photoinitiating performance of the photoinitiator under different conditions was evaluated based on the trend of conversion rate change over time under different test conditions.

[0282] Preparation of photocurable compositions:

[0283] (1) Prepare a free radical polymerizable photocurable composition 1 containing the compound of Example 3 as an oily photoinitiator according to the following composition:

[0284] 100 parts by weight of TPGDA acrylate monomer

[0285] 1 part by weight of the compound (photoinitiator) in Example 3

[0286] (2) Prepare photocurable compositions 2-15, each containing the compounds of Examples 1-14 as oil-based photoinitiators, according to the following composition:

[0287] 100 parts by weight of TPGDA acrylate monomer

[0288] EDB 1.16 parts by weight

[0289] 1 part by weight of the compounds (photoinitiators) in Examples 1-14

[0290] (3) Prepare photocurable compositions 16-29, each containing the compounds of Examples 1-14 as aqueous photoinitiators, according to the following formulations:

[0291] 100 parts by weight of PEG(400)DA acrylate monomer

[0292] GR54 4 parts by weight

[0293] 2 parts by weight of the compounds (photoinitiators) in Examples 1-14

[0294] (4) Prepare cationicly polymerizable photocurable compositions 30-32, each containing the compounds of Examples 1-3 as photoinitiators to sensitize iodonium salts, according to the following composition:

[0295] 100 parts by weight of 6110 epoxy monomer

[0296] GR54 4 parts by weight

[0297] 0.2 parts by weight of the compounds (photoinitiators) in Examples 1-14

[0298] (5) Prepare cationicly polymerizable photocurable compositions 33-35, each containing the compounds of Examples 1-3 as photoinitiators to sensitize thioonium salts, according to the following composition:

[0299] 100 parts by weight of 6110 epoxy monomer

[0300] GR-SS061 4 parts by weight

[0301] 0.2 parts by weight of the compounds (photoinitiators) in Examples 1-14

[0302] (6) Prepare a cationic polymerizable photocurable comparative composition 1 containing no compounds of the present invention according to the following composition:

[0303] 100 parts by weight of 6110 epoxy monomer

[0304] GR54 4 parts by weight

[0305] (7) Prepare a cationic polymerizable photocurable comparative composition 2 containing no compounds of the present invention according to the following composition:

[0306] 100 parts by weight of 6110 epoxy monomer

[0307] GR-SS061 4 parts by weight

[0308] Photoinitiation performance testing

[0309] After the above compositions are stirred and mixed evenly under yellow light, the photocurable compositions are injected into a pre-treated KBr double salt sheet mold that meets the following conditions using a syringe:

[0310] KBr double salt plate size: 15mm × 15mm

[0311] KBr double salt plate thickness: 3mm

[0312] KBr double salt plate gap: 0.5mm

[0313] By observing the syringe scale, the amount of photocurable composition injected into the KBr double salt plate mold was 0.2 ml. After injection, the KBr double salt plate mold was placed in the small black box of the Fourier transform infrared spectrometer used for real-time infrared testing. The structure of the small black box was such that the infrared test light above was vertically aligned and penetrated the KBr double salt plate mold, and the 45° LED point light source above the KBr double salt plate mold was aligned with the KBr double salt plate mold. The distance between the LED point light source and the KBr double salt plate mold was 1 cm.

[0314] Simultaneously, infrared spectroscopy detection and LED light source are activated, allowing the photocurable composition in the KBr double salt plate mold to be exposed while detecting changes in the area of ​​characteristic peaks.

[0315] Under the illumination of an LED point light source, photopolymerizable compounds undergo polymerization in the presence of an initiator, resulting in the formation of carbon-carbon double bonds (1630 cm⁻¹). -1 ) or epoxy functional group (916cm) -1 The area of ​​the characteristic peak continuously decreases until it almost disappears. Based on the data on the change of the characteristic peak area with exposure time, the conversion rate of the monomer over time is calculated.

[0316] Based on the data on the change of characteristic peak area of ​​carbon-carbon double bonds or epoxy functional groups with exposure time, the formula for the conversion rate of monomers with time is obtained:

[0317]

[0318] The compounds of Examples 1-14 were studied in combination with EDB (photocurable compositions 2-15) at 365nm, 385nm, 400nm, 415nm, 425nm, 450nm, and 475nm LED light sources (luminous intensity: 100mW / cm²). 2 The polymerization of oil-soluble acrylate monomer TPGDA was initiated under an exposure of 300 seconds. The final double bond conversion rate (%) of TPGDA after exposure is shown in Table 3.

[0319] Table 3

[0320]

[0321] The compounds of Examples 1-14 were tested in combination with iodonium salt GR54 (photocurable compositions 16-29) at 365nm, 385nm, 400nm, 415nm, 425nm, 450nm, and 475nm LED light sources (luminous intensity: 100mW / cm²). 2 The polymerization of waterborne acrylate resin (PEG(400)DA) was initiated under an exposure of 300 seconds. The final double bond conversion rate (%) of PEG(400)DA after exposure is shown in Table 4.

[0322] Table 4

[0323]

[0324]

[0325] In addition, the kinetic curves of the double bond conversion rate of monomer TPGDA of photocurable composition 1 using the compound of Example 3 as a function of time were tested under light sources of 415 nm, 450 nm, and 475 nm. Figure 2 a). Data shows that the monomer exhibits high conversion efficiency and conversion rate under all three light sources. The conversion efficiency at 30s is: 415nm: 72.6%; 450nm: 70.6%; 475nm: 69.0%, therefore 415nm is the optimal choice. Figure 2 a). At 415nm, 50mW / cm 2 Under a light source, the conversion rates of photocurable compositions 2, 3, and 4, containing the compounds of Examples 1-3, the amine (EDB), and the monomer TPGDA, were tested as a function of exposure time. Figure 2 b), wherein the conversion rates at 30 s were: Compound 1 + EDB: 77.7%; Compound 2 + EDB: 72.5%; Compound 3 + EDB: 76.8%.

[0326] At 415nm LED, 100mW / cm 2 Under LED light source, the conversion rate versus exposure time of photocurable compositions 16, 17, and 18, containing compounds from Examples 1-3, iodonium salt GR54, and PEG(400)DA, was tested. Figure 2 c) The conversion rates at 30 s were: Compound 1 + GR54: 64.7%; Compound 2 + GR54: 70.8%; Compound 3 + GR54: 74.5%. The experimental results show that the compounds of Examples 1-3 can rapidly initiate the photopolymerization of acrylate resin (PEG(400)DA), and the final double bond conversion rate can reach 80%.

[0327] At 415nm LED, 100mW / cm 2 Under a specific light source, photocurable compositions 30 and 32, containing compounds of Examples 1 or 3, iodonium salt GR54, and epoxy monomer (6110), and a comparative photocurable composition 1 containing only iodonium salt GR54 and epoxy monomer (6110), were tested to show the conversion rate versus exposure time. Figure 3a) where the conversion rates at 100 s were: Compound 1 + GR54: 38.0%; Compound 3 + GR54: 37.5%; GR54 only: 13.1%. Data shows that the two-component system of the compound of this invention / GR54 (0.2% / 4% w / w) can initiate the ring-opening polymerization of epoxy monomer 6110 under a 415 nm LED light source with good efficiency. Figure 3 a) Under the same conditions, the polymerization rate of epoxy monomer 6110 was lower when GR54 was used alone, which indicates that the compound of the present invention can effectively sensitize iodonium salt to achieve efficient cationic photocuring.

[0328] At 415nm LED, 100mW / cm 2 Under a specific light source, photocurable compositions 33, 34, and 35, containing compounds from Examples 1-3, thioonium salt GR-SS061, and epoxy monomer (6110), and a comparative photocurable composition 2 containing only thioonium salt GR-SS061 and epoxy monomer (6110), were tested to show the conversion rate versus exposure time. Figure 3 b), wherein the conversion rates at 100 s were: Compound 1 + GR-SS061: 63.6%; Compound 2 + GR-SS061: 60.4%; Compound 3 + GR-SS061: 44.2%; GR-SS061 only: 0. Data shows that the two-component system of the compound of this invention / GR-SS061 (0.2% / 4% w / w) can initiate the ring-opening polymerization of epoxy monomer 6110 under a 415 nm LED light source with good efficiency ( Figure 3 b). Under the same conditions, the polymerization rate of epoxy monomer 6110 was very low when GR-SS061 was used alone. This result indicates that the compound of the present invention can effectively sensitize thioonium salts to achieve efficient cationic photocuring.

[0329] Characterization 3: Deep curing performance test

[0330] The compounds from Examples 1 and 2 were used as photoinitiators to initiate the curing of acrylates (TPGDA, PEG(400)DA), demonstrating their deep curing capabilities. The curing depth of the acrylates after 5 minutes of exposure is shown in [Figure 1]. Figure 4 The photoinitiating performance of the photoinitiator under different conditions was evaluated based on the trend of curing depth change under different test conditions.

[0331] Specifically, the photoinitiation properties of the compound were tested according to the following steps.

[0332] (i) Prepare a photocurable composition (i) according to the following composition:

[0333] TPGDA 100 parts by weight

[0334] 0.01 parts by mass of the compound in Example 1

[0335] (ii) Prepare a photocurable composition according to the following composition:

[0336] TPGDA 100 parts by weight

[0337] 0.01 parts by mass of the compound in Example 2

[0338] (iii) Prepare a photocurable composition (iii) according to the following composition:

[0339] PEG(400)DA 100 parts by weight

[0340] 0.01 parts by weight of photoinitiator in Example 1

[0341] (iv) Prepare a photocurable composition according to the following formulation:

[0342] PEG(400)DA 100 parts by weight

[0343] 0.01 parts by mass of the compound in Example 2

[0344] After the above compositions were stirred and dissolved evenly under yellow light, the light-cured compositions were injected into a glass tube with an inner diameter of 1 cm and a length of 10 cm using a syringe, and then wrapped with aluminum foil. A light intensity of 100 mW / cm² was used. 2 A 415nm LED light source was used to irradiate the bottom of the test tube. After irradiation, the curing depth of the sample was measured, and the results are shown in [Figure number missing]. Figure 4 Experimental results show that a photoinitiator with a mass concentration of 0.01% (parts per ten thousand) can initiate polymerization of two monomers to a depth of over 9 cm within 5 minutes of exposure. Specifically, the curing depths of the photocurable compositions (i)-(iv) are 9.0 cm, 9.5 cm, 9.0 cm, and 9.2 cm, respectively (see [references]). Figure 4 (a), 4(b), 4(c) and 4(d)). This demonstrates that the compounds of the present invention possess excellent photoinitiation properties.

Claims

1. The 3-formylcoumarin compound of formula (I): (I) in: R1 is H or a linear or branched C2-C. 12 alkyl; R2 is H, linear or branched C2-C 12 Alkyl, diC1-C4 alkylamino or C1-C 16 Alkoxy(sulfide) group; R3 is H, linear or branched C2-C 12 Alkyl or C1-C 16 Alkoxy(sulfide) group; R4 is H, linear or branched C2-C 12 Alkyl or C1-C 16 Alkoxy(sulfide) group; and R5 is H; or R1, R2, and R3, together with their bonded carbon atoms, form an 8, 9, or 10-member partially unsaturated biheterocycle fused to the benzene ring in the coumarin structure, wherein the biheterocycle is unsubstituted or contains one or more independent substituents selected from the group consisting of C1-C4 alkyl groups, and the biheterocycle contains one N heteroatom as a ring member. Among them, at least one of R1, R2, R3 and R4 is not H and R5 is H.

2. The 3-formylcoumarin compound of formula (I) according to claim 1, wherein the biheterocycle contains one N heteroatom as a ring member, and the N heteroatom is a shared atom of the biheterocycle.

3. The 3-formylcoumarin compound of formula (I) according to claim 1, wherein the biheterocycle has the structure of formula (a): (a) in Indicates the position where the coumarin structure fuses with the benzene ring; and The structure shown in formula (a) is not substituted or contains one or more C1-C4 alkyl groups as substituents.

4. A 3-formylcoumarin compound of formula (I) according to any one of claims 1-3, wherein two or three of R1, R2, R3 and R4 are H and R5 is H.

5. A 3-formylcoumarin compound of formula (I) according to any one of claims 1-3, wherein the 3-formylcoumarin compound of formula (I) is selected from the group consisting of: 。 6. A method for preparing a 3-formylcoumarin compound of formula (I) as claimed in any one of claims 1-5, comprising the following steps: (1) Knoevenagel condensation: Compound (II) is subjected to a Knoevenagel condensation reaction with a C1-C6 alkyl ester of acetoacetic acid to obtain compound (III): (2) Oxidation reaction: The compound of formula (III) is oxidized with an oxidizing agent to obtain the compound of formula (I). In the above formulas, R1, R2, R3, R4 and R5 are defined as in any one of claims 1-5.

7. Use of the 3-formylcoumarin compound of formula (I) according to any one of claims 1-5 as a photoinitiator.

8. The use according to claim 7, wherein the 3-formylcoumarin compound of formula (I) is used as a pyrolysis-type photoinitiator or a hydrogen-abstracting-type photoinitiator in a UV-VIS LED light source curing system.

9. The use according to claim 8, wherein the 3-formylcoumarin compound of formula (I) is used as a pyrolysis-type photoinitiator or a hydrogen-abstraction-type photoinitiator in a UV-VIS LED light source curing system with a radiation wavelength of 300-550 nm.

10. The use according to claim 9, wherein the 3-formylcoumarin compound of formula (I) is used as a pyrolysis-type photoinitiator or a hydrogen-abstraction-type photoinitiator in a UV-VIS LED light source curing system with a radiation wavelength of 365-475 nm.

11. The use according to any one of claims 7-10, wherein the 3-formylcoumarin compound of formula (I) is used in combination with a compound selected from tertiary amine compounds, α-amino acid compounds or thiols.

12. Use of the 3-formylcoumarin compound of formula (I) as a photoinitiator sensitizing ononium salt according to any one of claims 1-5.

13. The use according to claim 12, wherein the 3-formylcoumarin compound of formula (I) is used as a photoinitiator for sensitizing onium salts.

14. The use according to claim 12, wherein the 3-formylcoumarin compound of formula (I) is used as a photoinitiator for sensitizing onium salts in a UV-VIS LED light source curing system.

15. The use according to claim 12, wherein the 3-formylcoumarin compound of formula (I) is used as a photoinitiator for sensitizing onium salts in a light source curing system with a radiation wavelength of 300-550 nm.

16. The use according to claim 12, wherein the 3-formylcoumarin compound of formula (I) is used as a photoinitiator for sensitizing onium salts in a light source curing system with a radiation wavelength of 365-475 nm.

17. The use according to claim 12, wherein the onium salt is selected from iodonium salts and thionium salts.

18. The use according to claim 12, wherein the onium salt is selected from diaryliodoonium salts and triarylthionium salts.

19. A photoinitiator composition comprising the 3-formylcoumarin compound of formula (I) according to any one of claims 1-5.

20. The photoinitiator composition of claim 19, wherein the photoinitiator composition comprises a 3-formylcoumarin compound of formula (I) and a compound selected from tertiary amine compounds, α-amino acid compounds or thiols.

21. The composition of claim 19, wherein the photoinitiator composition comprises the 3-formylcoumarin compound of formula (I) and an onium salt.

22. The photoinitiator composition of claim 21, wherein the onium salt is selected from iodonium salts and thionium salts.

23. The photoinitiator composition of claim 21, wherein the onium salt is selected from diaryliodoonium salts and triarylthionium salts.

24. A photocurable composition comprising at least one 3-formylcoumarin compound of formula (I) as claimed in any one of claims 1-5 or a photoinitiator composition as claimed in claim 19.

25. A cured material obtainable from the photocurable composition of claim 24.

26. A method for preparing a photocurable material, comprising irradiating the photocurable composition of claim 24 with a light source having a radiation wavelength of 300-550 nm.

27. The method of claim 26, further comprising irradiating the photocurable composition of claim 24 with a light source having a radiation wavelength of 365-475 nm.

28. The method of claim 26, further comprising irradiating the photocurable composition of claim 24 with a UV-VIS LED light source.

Images