Cyanine photoinitiator as well as preparation method and application thereof

Abstract

The invention provides a cyanine photoinitiator as well as a preparation method and application thereof. The cyanine photoinitiator comprises a compound with a structure as shown in a formula (1), wherein R1 and R2 are independently selected from hydrogen, halogen or substituted or unsubstituted aryl groups formed by the R1 and R2 and carbon atoms connected with the R1 and R2; r3 and R4 are independently selected from hydrogen, halogen or substituted or unsubstituted aryl groups formed by the R3 and R4 and carbon atoms connected with the R3 and R4; x is a halogen atom; y is selected from substituted or unsubstituted aryl and substituted or unsubstituted amido; z is selected from halogen atoms. The cyanine photoinitiator provided by the invention can initiate a photopolymerization reaction in a near-infrared light region. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of photocurable resin lenses, and particularly relates to a cyanine photoinitiator, a preparation method thereof, and uses thereof. Background Art

[0002] The photocuring technology is a process in which a photosensitizer generates initiating active species under light irradiation, causing the prepolymers and monomers in the system to undergo polymerization crosslinking reactions, and then realizing the rapid transformation of substances from liquid to solid. The advantages of photopolymerization lie in its fast curing rate, high efficiency, no volatile organic compounds (VOCs), good safety, etc., and it has a wide range of applications in the fields of 3D printing, resin lenses, dentistry, coatings and paints, etc. In the photocuring technology, a photoinitiator or a photoinitiating system that can initiate the polymerization of resin under light irradiation is essential.

[0003] Photoinitiators can also be classified into ultraviolet photoinitiators, visible light photoinitiators, near-infrared photoinitiators, etc. according to the wavelength of the absorbed radiation energy. Since traditional photopolymerization technology uses an ultraviolet mercury lamp as a light source, ozone and mercury pollution will be generated during the polymerization process, and the energy consumption is relatively high, and it has certain damage to the human eyes and skin. Compared with ultraviolet light, near-infrared light has obvious advantages: near-infrared light has low energy, weak radiation, and is safer for operators; the thermal effect released by the near-infrared light source is helpful for photopolymerization; near-infrared light has stronger penetrability and can achieve deeper photocuring, and is more suitable for the curing of thick and filled materials. Therefore, with the rapid development of the research on near-infrared photopolymerization, more requirements are also put forward for the design and research of near-infrared photoinitiators.

[0004] Therefore, developing an efficient near-infrared photoinitiator has become a technical problem to be solved urgently. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a cyanine photoinitiator, a preparation method thereof, and uses thereof. The cyanine photoinitiator of the present invention has high photoinitiating efficiency and good photocuring effect.

[0006] To this end, the present invention provides a near-infrared cyanine photoinitiator, comprising a compound having the structure shown in formula (1):

[0007]

[0008] In the formula, R1 and R2 each independently selected from hydrogen, halogen or together with the carbon atom to which they are attached form a substituted or unsubstituted aryl group; R3 and R4 each independently selected from hydrogen, halogen or together with the carbon atom to which they are attached form a substituted or unsubstituted aryl group; X is a halogen atom; Y is selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group; Z is selected from a halogen atom.

[0009] In some embodiments, each of R1 and R2 is independently selected from hydrogen or forms a substituted or unsubstituted monocyclic aromatic hydrocarbon together with the carbon atom to which they are attached; and / or each of R3 and R4 is independently selected from hydrogen or forms a substituted or unsubstituted monocyclic aromatic hydrocarbon together with the carbon atom to which they are attached.

[0010] In some embodiments, X is a chlorine atom; Y is selected from phenyl or dimethylamino; Z is an iodide ion.

[0011] In some embodiments, the photoinitiator includes one or more of the compounds having the structures shown in Formula (2) - Formula (5):

[0012]

[0013]

[0014] In some embodiments, the maximum absorption wavelength of the cyanine photoinitiator is in the range of 700 nm - 900 nm, preferably in the range of 750 nm - 850 nm.

[0015] The second aspect of the present application provides a method for preparing the above-mentioned cyanine photoinitiator, comprising the following steps:

[0016] Step S1, refluxing the compound of Formula A, haloethane and acetonitrile under anaerobic conditions at 80 °C - 90 °C for 10 h - 14 h to obtain Intermediate I;

[0017]

[0018] Step S2, dissolving the compound of Formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate and tetrakis(triphenylphosphine)palladium in a mixed solution of 1,4-dioxane and water, and refluxing under anaerobic conditions at 100 °C - 110 °C for 20 h - 24 h to obtain Intermediate II;

[0019]

[0020] Step S3, dissolving Intermediate II in a mixed solution of N,N-dimethylformamide and dichloromethane, and then slowly dropping phosphorus oxychloride (or phosphorus oxybromide) into the above-mentioned mixed solution, and refluxing under anaerobic conditions at 50 °C - 60 °C for 4 h - 6 h to obtain Intermediate III;

[0021]

[0022] Step S4, dissolving Intermediate I and III in a mixed solution of n-butanol and toluene, and refluxing under anaerobic conditions at 100 °C - 110 °C for 4 h - 6 h to obtain the compound of Formula (1);

[0023]

[0024] In some embodiments, in step S1, the molar ratio of the compound of formula A to haloethane is 1:1 to 1:1.3.

[0025] In some embodiments, in step S2, the molar ratio of the compound of formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate to tetrakis(triphenylphosphine)palladium is 1 to 1.2:1:5:0.08.

[0026] In some embodiments, in step S2, in the mixed solution of 1,4-dioxane and water, the volume ratio of 1,4-dioxane to water is 3:1 to 4:1.

[0027] In some embodiments, in step S3, phosphorus oxychloride is slowly added dropwise in an ice-water bath.

[0028] In some embodiments, in step S4, the molar ratio of intermediate I to intermediate III is 2:1 to 3:1.

[0029] In some embodiments, in step S4, in the mixed solution of n-butanol and toluene, the volume ratio of n-butanol to methanol is 7:3 to 7.5:2.5.

[0030] The third aspect of the present application further provides a use of the above-mentioned cyanine photoinitiator in a photopolymerization reaction, wherein the photopolymerization reaction includes carrying out a photopolymerization reaction on a polymerizable monomer and the cyanine photoinitiator under irradiation with light having a wavelength of 700 nm - 900 nm to obtain a photocured product.

[0031] In some embodiments, the addition amount of the cyanine photoinitiator relative to the total mass of the polymerizable monomer is less than or equal to 0.1%, preferably less than or equal to 0.05%.

[0032] In some embodiments, the photopolymerization reaction further includes mixing the polymerizable monomer, the cyanine photoinitiator and an ultraviolet photoinitiator, and then carrying out a near-infrared photopolymerization reaction under irradiation with light having a wavelength of 700 nm - 900 nm, preferably 770 nm - 810 nm; and then carrying out an ultraviolet photopolymerization under irradiation with light having a wavelength of 340 nm - 380 nm to obtain a photocured product.

[0033] In some embodiments, the polymerizable monomer includes one or more of acrylate monomers and styrene monomers.

[0034] In some embodiments, the ultraviolet photoinitiator is selected from one or more of benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0035] In some embodiments, the addition amount of the ultraviolet light initiator is less than or equal to 0.2% by mass based on the total mass of the polymerizable monomers, and preferably less than or equal to 0.1%.

[0036] In some embodiments, the photocured product is used as a lens.

[0037] The absorption bands of the photoinitiators provided by the present invention are all in the near-infrared light region. Among them, the maximum absorption wavelength of the cyanine photoinitiators of formula (2) and formula (3) is around 783 nm, and the maximum absorption wavelength of formula (4) and formula (5) is around 823 nm. The molar extinction coefficients of the cyanine photoinitiators of the present invention are all above 3×10 5 L mol -1 cm -1 above, and can all effectively absorb the energy of near-infrared light to reach the excited state. Only a very small amount of the photoinitiators provided by the present invention is required in the photopolymerization reaction to achieve good polymerization effect on thin (2-3 mm) resin samples. For example, the lowest concentration added can be one ten-thousandth of the mass of the polymerizable monomers, and a good polymerization effect can be achieved, and the conversion rate of double bonds is above 60%. The cyanine photoinitiators provided by the present invention also have the property of photobleaching and can be used for the preparation of resin lenses. The prepared resin lenses are uniform, transparent and have good molding. Using the cyanine photoinitiators provided by the present invention greatly shortens the preparation time of resin lenses and can achieve deep photopolymerization effect. Description of the Drawings

[0038] Figure 1 UV-Vis-NIR absorption spectra of four cyanine photoinitiators prepared in Examples 1-4;

[0039] Figure 2 Pictures before and after the polymerization of acrylate monomers initiated by four cyanine photoinitiators of Examples 1-4 with a concentration of 0.01 wt% each under near-infrared light irradiation;

[0040] Figure 3 FT-IR spectra of acrylate monomers before and after polymerization initiated by four cyanine photoinitiators of Examples 1-4 with a concentration of 0.01 wt% each under near-infrared light irradiation;

[0041] Figure 4 Flow chart for the preparation of resin lenses in Application Example 1 of the present application;

[0042] Figure 5 Resin lenses prepared in Application Example 1 of the present application, as well as the absorbance curve, transmittance curve, FT-IR spectrum and refractive index curve of the resin lenses. Detailed Embodiments

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0044] Throughout this specification, unless otherwise specifically stated, the terms used herein should be understood to have the meanings as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. In case of any contradiction, this specification shall prevail.

[0045] It should be noted that in the embodiments of the present invention, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a method or apparatus comprising a series of elements not only includes those elements expressly recited, but also includes other elements not expressly listed, or further includes elements inherent to the implementation of the method or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional related elements in the method or apparatus comprising such element.

[0046] It should be noted that the terms "first", "second", and "third" related to the embodiments of the present invention are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first", "second", and "third" can be interchanged with a specific order or sequence when permitted. It should be understood that the objects distinguished by "first", "second", and "third" can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0047] In the present invention, the term "photoinitiator", also known as photosensitizer or photocuring agent, refers to a class of compounds that can absorb energy of a certain wavelength in the ultraviolet region (10 nm - 400 nm), visible light region (400 - 700 nm) or near-infrared region (700 nm - 1000 nm), generating free radicals, cations, etc., thereby initiating the polymerization and crosslinking curing of polymerizable monomers. Among them, the term "ultraviolet photoinitiator" refers to a class of compounds that absorb energy in the ultraviolet region (10 nm - 400 nm) to initiate polymerization and crosslinking curing. The term "near-infrared photoinitiator" refers to a class of compounds that absorb energy in the near-infrared region (700 nm - 1000 nm) to initiate polymerization and crosslinking curing. The term "cyanine photoinitiator" refers to a photoinitiator including cyanine compounds, wherein the "cyanine compound" refers to a polymethine compound formed by connecting two indole groups (nitrogen-containing aromatic heterocycles) through an allenic structure (polyene-methine-like) of multiple carbon atoms.

[0048] In the present invention, the term "maximum absorption wavelength" refers to the wavelength corresponding to the maximum absorption of a certain form of radiation (such as light of different wavelengths, such as ultraviolet light, visible light, infrared light, etc.) in the absorption spectrum of a substance. The maximum absorption wavelength is determined by measuring the absorbance of the substance at different wavelengths.

[0049] In the present invention, the term "photopolymerization reaction", also known as "photocuring reaction", refers to a polymerization or crosslinking reaction initiated by light.

[0050] In the present invention, the term "photocured product" refers to a cured product obtained through a photopolymerization reaction.

[0051] This specification involves many chemical terms and abbreviations used by those skilled in the art. Definitions of selected terms are provided for clarity and consistency.

[0052] As used herein, the term "substituted" means that the parent compound or moiety has at least one (1) substituent group. The term "unsubstituted" means that the parent compound or moiety does not have other substituents except that the undetermined valence is chemically saturated by hydrogen atoms.

[0053] As used herein, the term "alkyl" refers to saturated hydrocarbons having from 1 to 12 carbon atoms, including straight-chain, branched-chain, and cyclic alkyls. Examples of alkyls include, but are not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, tert-butyl, sec-butyl, isobutyl, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. The term "alkyl" includes unsubstituted alkyls and substituted alkyls. The term "C1-Cn alkyl" (where n is an integer from 2 to 12) refers to an alkyl having from 1 to the indicated "n" carbon atoms. Alkyl residues can be substituted or unsubstituted. In some embodiments, for example, an alkyl can be substituted with groups such as hydroxyl, amino, carboxyl, carboxylic ester, amide, carbamate, or aminoalkyl.

[0054] The term "aryl" refers to an aromatic group having "4n + 2" (π) electrons in a conjugated monocyclic or polycyclic system (fused or unfused) and having from 6 to 14 ring atoms, where n is an integer from 1 to 3. The polycyclic system includes at least one aromatic ring. An aryl can be attached directly or through a C1-C3 alkyl (also referred to as arylalkyl or aralkyl). Examples of aryls include, but are not limited to, phenyl, benzyl, phenethyl, 1-phenylethyl, tolyl, naphthyl, biphenyl, terphenyl, indenyl, benzocyclooctenyl, benzocycloheptenyl, azulyl, acenaphthyl, fluorenyl, phenanthryl, anthracenyl, etc. The term aryl includes unsubstituted aryls and substituted aryls. The term "C6-Cn aryl" (where n is an integer from 6 to 15) refers to an aryl having from 6 to the indicated "n" carbon atoms in the ring structure, including at least one heterocyclic group or atom as defined above.

[0055] As used herein, the term "amino" refers to an unsubstituted or substituted moiety of the formula -NRaRb, where Ra and Rb are each independently hydrogen, alkyl, aryl, or heterocyclic group, or Ra and Rb together with the nitrogen atom to which they are attached form a heterocycle. The term amino includes compounds or moieties in which the nitrogen atom is covalently bonded to at least one carbon or heteroatom. Thus, as used herein, the terms "alkylamino" and "dialkylamino" refer to amino groups having one and at least two C1-C6 alkyls attached thereto, respectively. The terms "arylamino" and "diarylamino" include groups in which the nitrogen atom is bonded to at least one or two aryls, respectively. The term "amide" or "aminocarbonyl" includes compounds or moieties containing a nitrogen atom structure attached to the carbon of a carbonyl or thiocarbonyl. The term "acylamino" refers to an amino group directly attached to an acyl as defined herein.

[0056] The term "halogen" refers to an element of Group VIIA in the periodic table, exemplarily including fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), etc. The term "halogen ion" refers to an anion formed by a halogen, such as fluorine ion (F-), chloride ion (Cl-), bromide ion (Br-), iodine ion (I-), astatine ion (At-), etc.

[0057] The first aspect of the present invention provides a cyanine photoinitiator, wherein the cyanine photoinitiator comprises a compound having a structure shown in formula (1):

[0058]

[0059] In the formula, R1 and R2 are each independently selected from hydrogen, halogen or together with the carbon atom to which they are connected, they form a substituted or unsubstituted aryl group; R3 and R4 are each independently selected from hydrogen, halogen or together with the carbon atom to which they are connected, they form a substituted or unsubstituted aryl group; X is a halogen atom; Y is selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted amine group; and Z is selected from a halogen atom.

[0060] Due to its large π conjugated structure, the cyanine compound has an absorption wavelength concentrated in the red light and near-infrared region of 657nm to 1024nm, and has a high molar extinction coefficient in the near-infrared region, which can effectively absorb the energy of near-infrared light to reach an excited state, thereby being able to be used as a photosensitizer and a photoinitiator. The cyanine photoinitiator of the present invention not only has a cyanine skeleton structure, but also has a photoinitiator group connected, so that the compound has strong absorption in the near-infrared region, and can effectively absorb the energy of near-infrared light to reach an excited state, so that the internal electrons flow to the photoinitiator group, so that the photoinitiator group undergoes bond cleavage to generate initiating free radicals. In the presence of monomers, free radicals can initiate polymerization of the double bonds of the resin monomers, thereby converting the liquid resin into a solid state.

[0061] In some embodiments, R1 and R2 are each independently selected from hydrogen, halogen, or together with the carbon atom to which they are attached, form a substituted or unsubstituted monocyclic aromatic hydrocarbon.

[0062] In some embodiments, R3 and R4 are each independently selected from hydrogen, halogen, or together with the carbon atom to which they are attached, form a substituted or unsubstituted monocyclic aromatic hydrocarbon.

[0063] In some embodiments, X is a chlorine atom.

[0064] In some embodiments, Y is selected from phenyl or dimethylamino.

[0065] In some embodiments, Z is iodide.

[0066] In some embodiments, the initiator includes one or more of the compounds having the structures shown in Formula (2) - Formula (5):

[0067]

[0068] The absorption wavelengths of the compounds having the structures shown in Formula (2) - Formula (5) are all in the near-infrared light region. Under the excitation of near-infrared light, bond cleavage can occur to generate active free radicals, inducing the occurrence of polymerization reactions and realizing the photocuring of materials. In addition, the compounds having the structures shown in Formula (2) - Formula (5) also have the property of photobleaching. The above-mentioned cyanine photoinitiator dissolved in the resin presents a light green color. When irradiated with near-infrared light, the cyanine photoinitiator absorbs the energy of near-infrared light to reach the excited state, and the excited cyanine photoinitiator will decompose. First, the cleavage of the polymethine chains on both sides causes the color of the polymer to change from light green to lighter or even transparent, and then the cleavage of the bond at the carbonyl group generates free radicals to initiate the polymerization of monomers, which is beneficial to the preparation of high-transparency polymeric resin materials.

[0069] In some embodiments, the maximum absorption wavelength of the cyanine photoinitiator is in the range of 700 nm - 900 nm. The wavelength in the range of 700 nm - 900 nm is in the near-infrared light region. Near-infrared light has low energy and weak radiation, which is safer for operators. By making the maximum absorption wavelength of the cyanine photoinitiator within the above range, the cyanine photoinitiator can effectively absorb the energy of near-infrared light in the near-infrared light region to reach the excited state, realizing the photocuring of materials. In addition, the thermal effect released by the near-infrared light source further contributes to the photopolymerization reaction; near-infrared light has stronger penetrability, which is also beneficial to achieving deeper photocuring and is more suitable for the photocuring of thick and dense materials. Exemplarily, the maximum absorption wavelength of the cyanine photoinitiator can be 700 nm, 720 nm, 750 nm, 780 nm, 783 nm, 820 nm, 823 nm, 850 nm, 870 nm, 890 nm, 900 nm or a value between any two of them. In some alternative embodiments, the maximum absorption wavelength of the cyanine photoinitiator can be 750 nm - 850 nm.

[0070] The present invention also provides a method for preparing the above-mentioned cyanine photoinitiator, including the following steps:

[0071] Step S1, refluxing the compound of Formula A, haloethane and acetonitrile at 80°C - 90°C for 10 h - 14 h under an anaerobic condition to obtain Intermediate I;

[0072]

[0073] Step S2: Dissolve the compound of formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate, and tetrakis(triphenylphosphine)palladium in a mixed solution of 1,4-dioxane and water. Under anaerobic conditions, reflux at 100°C - 110°C for 20 h - 24 h to obtain Intermediate II;

[0074]

[0075] Step S3: Dissolve Intermediate II in a mixed solution of N,N-dimethylformamide and dichloromethane, and then slowly drop phosphorus oxychloride (or phosphorus oxybromide) into the above mixed solution. Under anaerobic conditions, reflux at 50°C - 60°C for 4 h - 6 h to obtain Intermediate III;

[0076]

[0077] Step S4: Dissolve Intermediate I and III in a mixed solution of n-butanol and toluene. Under anaerobic conditions, reflux at 100°C - 110°C for 4 h - 6 h to obtain the compound of formula (1);

[0078]

[0079] The method of the present invention is prepared from simple and readily available raw materials, the synthesis method is simple, and the purification process is easy to operate.

[0080] In some embodiments, in Step S1, the molar ratio of the compound of formula A to haloethane is 1:1 - 1:1.3. In Step S1, those skilled in the art can adjust the addition amount of acetonitrile according to the amounts of the compound of formula A and haloethane, and this application does not make specific limitations thereon. Exemplarily, the amount of acetonitrile used can be 40 mL - 80 mL.

[0081] In some embodiments, the compound of formula A is 2,3,3-trimethyl-3H-indole or 1,1,2-trimethyl-1H-benzo[e]indole. In some embodiments, the haloethane is iodoethane.

[0082] In some embodiments, in Step S1, after the reflux is completed, slowly cool the reaction solution to room temperature, precipitate and collect the solid product to obtain Intermediate I. The present invention does not make specific limitations on the cooling method, and it can be achieved by means known in the art. The precipitated solid product can be collected by methods known in the art, for example, collecting the solid product by filtration.

[0083] In some embodiments, in Step S2, the molar ratio of the compound of formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate to tetrakis(triphenylphosphine)palladium is 1 - 1.2:1:5:0.08.

[0084] In some embodiments, in the mixed solution of 1,4-dioxane and water, the volume ratio of 1,4-dioxane to water is 3:1 to 4:1. In step S2, those skilled in the art can adjust the amount of the mixed solution of 1,4-dioxane and water according to the amount of raw materials, and the present invention does not make special limitations thereon. Exemplarily, the amount of the mixed solution of 1,4-dioxane and water can be 40-100 mL.

[0085] In some embodiments, in step S2, after the reflux ends, intermediate II is separated from the reaction mixture solution by extraction. The extraction can be achieved by methods or devices known in the art, and the present invention does not make special limitations thereon.

[0086] In some embodiments, in step S3, phosphorus oxychloride is slowly added dropwise in an ice-water bath. The addition of phosphorus oxychloride will release a large amount of heat, so phosphorus oxychloride is slowly added dropwise in an ice-water bath.

[0087] In some embodiments, in step S4, the molar ratio of intermediate I to intermediate III is 2:1 to 3:1.

[0088] In some embodiments, in step S3, after the reflux is completed, the reaction mixture solution is poured onto ice, and the solid product is precipitated and collected to obtain intermediate III.

[0089] In some embodiments, in step S4, in the mixed solution of n-butanol and toluene, the volume ratio of n-butanol to methanol is 7:3 to 7.5:2.5.

[0090] In some embodiments, in step S4, after the reflux ends, the organic layer solution is collected by extraction, then concentrated under reduced pressure in vacuo, and then purified by silica gel column chromatography to obtain the compound of formula (1) as a dark green solid product.

[0091] On the other hand, the present invention also provides a use of the above-mentioned cyanine photoinitiator in a photopolymerization reaction, wherein the photopolymerization reaction includes carrying out a photopolymerization reaction on a polymerizable monomer and the cyanine photoinitiator under irradiation with light having a wavelength of 700 nm - 900 nm to obtain a photocured product.

[0092] The maximum absorption wavelength of the cyanine photoinitiator of the present invention is in the range of 700 nm - 900 nm, which can absorb the energy of light with a wavelength of 700 nm - 900 nm, excite to generate active free radicals, thereby initiating the polymerization reaction between polymerizable monomers, and subjecting the liquid polymerizable monomers to photopolymerization to obtain a photocured product. In addition, near-infrared light with a wavelength in the range of 700 nm - 900 nm has a thermal effect, which can further promote the photopolymerization reaction. Near-infrared light has good penetrability, so it is also beneficial to achieve a deeper photopolymerization reaction and achieve a better photocuring effect on thicker and denser polymerizable monomers. In some embodiments, the photopolymerization reaction includes subjecting the polymerizable monomers and the cyanine photoinitiator to photopolymerization under irradiation with light having a wavelength of 770 nm - 810 nm to obtain a photocured product. Photopolymerization within the above wavelength range has better polymerization efficiency.

[0093] In some embodiments, the addition amount of the cyanine photoinitiator relative to the total mass of the polymerizable monomers is less than or equal to 0.1%, preferably less than or equal to 0.05%. The cyanine photoinitiator of the present invention has excellent ability to initiate monomer polymerization. Only a small amount of the initiator can achieve a good polymerization effect on a thin resin sample (for example, with a thickness of 2 - 3 mm). By making the addition amount of the cyanine photoinitiator within the above range, it is beneficial to achieve a good polymerization effect. On the other hand, it is also beneficial to reduce the influence of the photoinitiator on the properties of the photocured product. For example, since the photoinitiator itself is dark green, the less the amount of the photoinitiator incorporated into the resin, the lighter the color of the polymerization product, which is beneficial to improving the transparency of the photocured product.

[0094] In some embodiments, the photopolymerization reaction further includes mixing the polymerizable monomers, the cyanine photoinitiator and a UV photoinitiator, and then performing near-infrared photopolymerization under irradiation with light having a wavelength of 700 nm - 900 nm, preferably 770 nm - 810 nm; and then performing UV photopolymerization under irradiation with light having a wavelength of 340 nm - 380 nm to obtain a photocured product. By performing the photopolymerization reaction under near-infrared light, due to the high penetrability of near-infrared light, it can effectively penetrate into the interior of the resin, achieve a rapid photocuring effect, shorten the photopolymerization reaction time, and further perform UV photopolymerization to further polymerize the resin that is still viscous on the surface, so that the resin as a whole reaches a better polymerization effect.

[0095] In some embodiments, the polymerizable monomer includes one or more of acrylate monomers and styrene monomers. The above polymerizable monomers have a wide range of uses in the preparation of lenses, coatings and paints, and the production of plastic products. In some embodiments, the polymerizable monomer includes acrylate monomers. The resulting photocured product has good optical properties, such as high transparency, high curing degree, and high refractive index value, and can thus be used to prepare high-quality resin lenses.

[0096] In some embodiments, the ultraviolet light initiator is selected from one or more of benzophenone (BP), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO).

[0097] In some embodiments, the addition amount of the ultraviolet light initiator is less than or equal to 0.2% by mass relative to the total mass of the polymerizable monomer, preferably less than or equal to 0.1%. Thus, through the combined synergistic action of the near-infrared light initiator and the ultraviolet light initiator, it is beneficial to quickly and efficiently achieve the polymerization effect of the resin.

[0098] In some embodiments, the photocured product is used as a lens.

[0099] Examples

[0100] The present invention will be more easily understood by reference to the following examples, which are used to illustrate the present invention and should not be construed as limiting the scope of the present invention in any way.

[0101] Example 1

[0102] Preparation of Intermediate I

[0103] In a 250 ml round-bottom flask, 2,3,3-trimethyl-3H-indole (10 g, 62.8 mmol), iodoethane (10.77 g, 69.08 mmol) and 80 ml of acetonitrile were added respectively and mixed evenly. Under a N2 atmosphere, the mixture was refluxed at 82 °C for 12 h. After the reaction was completed, it was cooled to room temperature and the reaction solution was cooled. After the precipitate was formed, it was filtered by suction using a Buchner funnel, and the obtained solid product was washed with acetonitrile and dried under vacuum.

[0104] Preparation of Intermediate II

[0105] In a 100 ml round-bottom flask, phenylboronic acid derivative (4-benzoylbenzeneboronic acid (0.492 g, 2.178 mmol)), 4-(4-bromophenyl) cyclohexanone (0.5 g, 1.98 mmol), potassium carbonate (1.37 g, 9.9 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.183 g, 0.158 mmol) were successively added to a mixed solution of 40 ml of 1,4-dioxane and H2O

[0106] (3∶1, v / v). Under a N2 atmosphere, the mixture was stirred at 100 °C for 24 h. After the reaction was completed, it was cooled to room temperature. The reaction solution was extracted with ethyl acetate and saturated NaCl solution, the organic layer was collected and dried over anhydrous sodium sulfate, and the organic layer was concentrated in vacuo. The crude product was purified by column chromatography using petroleum ether / ethyl acetate (4∶1, v / v) as the eluent to obtain a white solid, which was Intermediate II.

[0107] Preparation of Intermediate III

[0108] A mixed solution of 30 ml of N,N-dimethylformamide and 30 ml of dichloromethane was placed in a 250 ml round-bottom flask, the solution was cooled to -10 °C, and then stirred in an ice-water bath. Intermediate II (0.5 g, 1.41 mmol) was added to the above solution and stirred until completely dissolved, and then phosphorus oxychloride (30 mL) was slowly added dropwise to the above mixture. After the reaction solution was stirred at 60 °C for 6 h, it was cooled to room temperature, poured onto ice, allowed to stand overnight, and the precipitated yellow solid was collected by suction filtration through a Buchner funnel, which was Intermediate III.

[0109] Preparation of Cyanine Photoinitiator

[0110] A mixed solution of 100 mL of n-butanol and toluene (7:3, v / v) was added to a 250 mL round-bottom flask, and then Intermediate I (0.31 g, 1.636 mmol) and Intermediate III (0.35 g, 0.818 mmol) were added respectively. Under a N2 atmosphere, the reaction solution was refluxed at 110 °C for 6 h. After the reaction was completed, the solution was cooled to room temperature, extracted with ethyl acetate and saturated NaCl solution, the organic layer was collected and dried over anhydrous sodium sulfate, and the organic layer was concentrated in vacuo. The crude product was purified by silica gel column chromatography using ethyl acetate / methanol (8:1, v / v) as the eluent to obtain a dark green solid product, which was the compound of formula (2), named Cy-BP-1 (yield: 34.3%).

[0111] The NMR data were as follows:

[0112] Cy-BP-1: 11H NMR (400 MHz, Chloroform-d) δ 8.46 (d, J=14.0 Hz, 2H), 7.92

[0113] (dd, J=23.8, 7.8 Hz, 5H), 7.79 (d, J=7.7 Hz, 4H), 7.68 - 7.51 (m, 6H), 7.43 (d, J=7.9 Hz, 4H), 7.24 (d, J=7.9 Hz, 2H), 6.24 (d, J=14.1 Hz, 2H), 4.35 - 4.19 (m, 4H), 3.17 (d, J=16.3 Hz, 2H), 2.89 (d, J=12.8 Hz, 2H), 2.26 (t, J=7.7 Hz, 1H), 1.78 (s, 12H), 1.46 (t, J=7.1 Hz, 6H). 13 13C NMR (101 MHz, CDCl3) δ 196.43, 172.32, 149.95, 144.55, 141.67, 141.20, 138.85, 137.75, 132.44, 130.82, 130.02, 128.97, 128.36, 128.10, 127.85, 126.90, 126.26, 125.59, 122.33, 110.95, 100.81, 49.53, 39.89, 38.55, 33.83, 28.09, 28.05, 12.52. HRMS (ESI) m / z calcd for C 53 H 52 ClN2O + (M) + 767.3768, found 767.3757.

[0114] Example 2

[0115] The cyanine photoinitiator was prepared according to a preparation method similar to that of Example 1, except that in the preparation step of Intermediate II, the phenylboronic acid derivative was 4-(N,N-dimethylcarbamoyl)phenylboronic acid (0.43 g, 2.182 mmol), and the compound of formula (3) was prepared and named Cy-DMB-1 (yield: 40.3%).

[0116] The NMR data are

[0117] Cy-DMB-1: 1 1H NMR (400 MHz, Chloroform-d) δ 8.45 (d, J=14.1 Hz, 2H),

[0118] 7.70 (dd, J = 13.3, 8.1 Hz, 4H), 7.56 (dd, J = 15.7, 8.2 Hz, 4H), 7.44 (t, J = 7.7 Hz, 4H), 7.30 (d, J = 7.6 Hz, 2H), 7.23 (d, J = 7.9 Hz, 2H), 6.20 (d, J = 14.1 Hz, 2H), 4.25 (p, J = 7.2 Hz, 4H), 3.13 (d, J = 31.3 Hz, 8H), 2.90 - 2.77 (m, 2H), 2.28 - 2.23 (m, 1H), 1.77 (d, J = 1.7 Hz, 12H), 1.45 (t, J = 7.1 Hz, 6H). 13 C NMR (101 MHz, CDCl3) δ172.33, 144.58, 141.64, 141.21, 129.00, 127.94, 127.73, 127.69, 127.00, 126.24, 125.61, 122.33, 110.95, 100.71, 49.54, 39.82, 38.66, 33.85, 28.09, 28.05, 12.50. HRMS (ESI) m / z calcd for C 49 H 53 ClN3O + (M) + 734.3872, found 734.3876.

[0119] Example 3

[0120] The cyanine initiator was prepared by a method similar to that of Example 1, except that in the preparation step of Intermediate I, the compound of formula A was 1,2,2 - trimethyl - 1H - benzo[e]indole (10 g, 47.82 mmol), and the compound of formula (4) was prepared and named Cy - BP - 2 (yield: 26.3%).

[0121] The NMR data are

[0122] Cy - BP - 2: 1 H NMR (400 MHz, Chloroform - d) δ8.56 (d, J = 14.1 Hz, 2H), 8.17

[0123] (d, J = 8.6 Hz, 2H), 8.03 - 7.92 (m, 6H), 7.89 (d, J = 6.9 Hz, 2H), 7.79 (dd, J = 8.2, 3.3 Hz, 4H), 7.69 - 7.62 (m, 5H), 7.53 (dd, J = 19.9, 8.4 Hz, 6H), 6.27 (d, J = 14.2 Hz, 2H), 4.39 (p, J = 7.4 Hz, 4H), 3.20 (d, J = 16.4 Hz, 2H), 2.96 - 2.83 (m, 2H), 2.30 - 2.19 (m, 1H), 2.07 (s, 12H), 1.51 (t, J = 7.1 Hz, 6H). 13 C NMR(101MHz, CDCl3) δ 173.64, 144.80, 144.48, 143.58, 139.17, 137.74, 136.31, 134.11, 132.44, 132.09, 131.00, 130.83, 130.23, 130.02, 128.36, 128.10, 127.86, 126.91, 126.07, 125.29, 122.17, 110.74, 100.46, 51.31, 40.08, 38.30, 33.87, 27.66, 27.58, 12.83. HRMS(ESI) m / z calcd for C 61 H 56 ClN2O + (M) + 867.4076, found 867.4065.

[0124] Example 4

[0125] The cyanine initiator was prepared by a method similar to that of Example 3, except that in the preparation step of Intermediate II, the phenylboronic acid derivative was 4-(N,N-dimethylcarbamoyl)phenylboronic acid (0.43 g, 2.182 mmol), and the compound of formula (5) was prepared and named Cy-DMB-2 (yield: 35.3%).

[0126] The NMR data are

[0127] Cy-DMB-2: 1 H NMR(400MHz, Chloroform-d) δ 8.56 (d, J = 14.2 Hz, 2H),

[0128] 8.17 (d, J = 8.6 Hz, 2H), 8.03 - 7.93 (m, 4H), 7.78 - 7.47 (m, 14H), 6.23 (d, J = 14.2 Hz, 2H), 4.45 - 4.28 (m, 4H), 4.13 (t, J = 7.1 Hz, 1H), 3.23 - 3.04 (m, 8H), 2.93 - 2.78 (m, 2H), 2.07 (d, J = 1.9 Hz, 12H), 1.51 (t, J = 7.1 Hz, 6H). 13 C NMR (101 MHz, CDCl3) δ 173.56, 171.51, 149.23, 143.94, 143.49, 142.04, 139.32, 139.14, 135.15, 134.09, 132.07, 131.01, 130.24, 128.11, 128.01, 127.85, 127.76, 127.72, 127.03, 126.15, 125.29, 122.09, 110.76, 100.35, 51.30, 40.10, 38.76, 33.93, 27.67, 27.59, 12.87. HRMS (ESI) m / z calcd for C 57 H 57 ClN3O + (M) + 834.4185, found 834.4177.

[0129] Test Example 1

[0130] Test for the maximum light absorption wavelength

[0131] The UV-Vis-NIR absorption spectra of the cyanine photoinitiators of Examples 1 - 4 were tested using a T9 type UV-Vis-NIR spectrophotometer and are shown in Figure 1 .

[0132] Analysis of the absorption spectra shows that the main absorption peaks of the four cyanine photoinitiators are all in the near-infrared light region. Among them, Cy-BP-1 and Cy-DMB-1 have strong absorption in the range of 700 - 810 nm, and the maximum absorption wavelength is around 783 nm. Cy-BP-2 and Cy-DMB-2 have strong absorption in the range of 730 - 850 nm, and the maximum absorption wavelength is around 823 nm. The maximum molar extinction coefficient (ε max ) of these four cyanine photoinitiators is greater than 3×10 5 L mol -1 cm -1 . The molar extinction coefficient is calculated by the formula It is calculated that A is the absorbance, which is measured by an ultraviolet-visible-near-infrared spectrophotometer; c is the concentration of the prepared solution, and in this embodiment, c = 5×10 -6 mol L -1 ; L is the optical path length of the cuvette, and in this embodiment, L = 1 cm.

[0133] The cyanine photoinitiator of the present invention exhibits good light absorption ability in the near-infrared region, indicating that it can effectively absorb the energy of near-infrared light to reach the excited state and has the potential to be used as a photosensitizer.

[0134] Test Example 2

[0135] Double bond conversion rate

[0136] Four cyanine photoinitiators of Examples 1-4 were subjected to a photopolymerization experiment, and the double bond conversion rates of the polymerizable monomers before and after polymerization were studied by infrared spectroscopy. The specific experimental steps are as follows:

[0137] Prepare four equal-mass portions of acrylate polymerizable monomers, and add the four cyanine photoinitiators of Examples 1-4 respectively in an amount of 0.01 wt% of the total mass of the polymerizable monomers to prepare four polymerization reaction mixtures. According to the maximum absorption wavelength of the cyanine photoinitiator, a near-infrared light source is selected. Among them, Cy-BP-1 and Cy-DMB-1 use near-infrared light of 770-780 nm as the irradiation source, and Cy-BP-2 and Cy-DMB-2 use near-infrared light of 800-810 nm as the irradiation source. The above four polymerization reaction mixtures are respectively placed under the corresponding near-infrared light source for irradiation, and the curing situation of the resin is observed. During this period, the distance of the light source can be adjusted according to the curing situation. After obtaining a better curing effect (the whole resin does not flow and is not sticky, and in terms of double bond conversion rate, it is generally considered that a curing effect is better when it is above 60%), stop irradiation, record the curing time, and take pictures of the resin before and after curing, as Figure 2 shown.

[0138] It can be seen from Figure 2 that after near-infrared light irradiation, when the doping amount is 0.01 wt%, all four cyanines can effectively initiate the polymerization of the monomers. The four polymerization reaction mixtures have all undergone polymerization reactions, changing from liquid to solid, and the color of the mixture has changed significantly after irradiation, fading from dark green to orange-red or even light red, which is caused by the photobleaching property of the cyanine.

[0139] The four polymerization reaction mixtures were tested by an infrared spectrometer, and the test results are shown in Figure 3 . By monitoring the absorption at 750-1000 cm -1 or 1550-1650 cm -1The change of the infrared absorption peak at a certain position is used to study the photopolymerization conversion rate. The double bond conversion rate of the monomer is calculated by the formula double bond conversion rate (%) = [1 - A t / A0] × 100%. Wherein, A0 and A t are the areas of the infrared absorption peaks before and after polymerization, respectively. The double bond conversion rates of the polymerizable monomers in each polymerization reaction mixture are shown in Table 1.

[0140] Table 1

[0141]

[0142] From Figure 3 and the results in Table 1, it can be seen that the final double bond conversion rates (FC) of Cy - BP - 1 and Cy - DMB - 1 are above 70%, and the FC of Cy - BP - 2 and Cy - DMB - 2 can also reach above 60%. Thus, it can be seen that the cyanine photoinitiators of the present invention all exhibit excellent single - component photoinitiating ability and can effectively initiate the polymerization of acrylate resin monomers.

[0143] Application Example 1

[0144] Application of Cyanine Photoinitiator in the Preparation of Resin Lenses

[0145] Use the KR60 resin monomer provided by Jiangsu Mingyue Optical Lens Co., Ltd. (composition: polyethylene glycol acrylate, styrene, methyl styrene copolymer, bisphenol A epoxy acrylate, etc.). Use the cyanine photoinitiator prepared in Example 1 as the near - infrared photoinitiator and benzophenone as the ultraviolet light co - initiator, and carry out the preparation of resin lenses according to the preparation process as Figure 4 shown.

[0146] The specific steps are as follows: Mix the KR60 resin monomer with the near - infrared photoinitiator Cy - BP - 1 in Example 1 (the addition amount is 0.01 wt% of the total mass of the resin monomer) and the ultraviolet light initiator benzophenone (the addition amount is 0.1 wt% of the total mass of the resin monomer) together, and stir evenly until all solids are completely dissolved to obtain a homogeneous and transparent photocurable resin system. Pour the photocurable resin system into a glass mold, irradiate it under near - infrared light at 770 - 780 nm for 30 min, and then irradiate it under ultraviolet light at 365 nm for 30 min to further cure and form the resin system. Under ultrasonic conditions, wash the resin lens in the mold with acetone, absolute ethanol, and dichloromethane respectively; then heat - treat the mold. After reaching a certain temperature, since the resin lens becomes soft due to the temperature rise, carefully remove the resin lens from the mold at this time, lay it flat and cool to obtain the lens.

[0147] It was found during the preparation process that after 30 minutes of irradiation with near-infrared light, the resin faded from green and became lighter, and the resin system had already been cured and formed, with only a little viscous resin liquid remaining on the surface.

[0148] Then, the prepared resin lenses were tested for degree of polymerization, refractive index, and light transmittance. Among them, the degree of polymerization of the lenses was characterized by the double-bond conversion rate of the infrared spectra before and after the polymerization of KR60 resin; the refractive index of the lenses was obtained by testing with a HORIBA France SAS type ellipsometer; the absorption spectrum of the lenses at 200 - 800 nm was tested using a LAMBDA 950 type ultraviolet / visible / near-infrared spectrophotometer, and the light transmittance was calculated by the formula A = -lg T, where A is the absorbance and T is the light transmittance. The test results are shown in Figure 5 .

[0149] Figure 5 . In (a) of it are the absorption curve and light transmittance curve of the lenses. The light transmittance curve in the illustration shows that the prepared lenses have a high transparency in the visible spectral region (400 - 700 nm), all above 90%, indicating that the lenses have good light transmittance.

[0150] Figure 5 . In (b) of it are the infrared spectra of the lenses before and after polymerization. The infrared spectra show that the peak at 750 - 810 cm -1 has decreased significantly. By integrating the absorption peak area, the FC of the lenses is 88.1%, indicating that the lenses have good curing and forming degree and the surface of the lenses is not viscous.

[0151] Figure 5 . In (c) of it is the refractive index curve of the lenses. Currently, most existing acrylate polymers exhibit a low refractive index (~1.50). The refractive index curve of the lenses shows that the refractive index of the lenses at 589 nm is 1.53. This type of KR60 acrylate monomer has a high refractive index, and the lenses prepared using this monomer have thinner edges.

[0152] Through the curing method combining near-infrared light and ultraviolet light, first using near-infrared light for curing can achieve a deeper curing depth, a faster curing speed, and a better curing and forming degree; then, the final preparation of the lenses is completed by ultraviolet light curing for a shorter time. Compared with the traditional ultraviolet light curing method, this method greatly reduces the use of ultraviolet light during the curing process, significantly improves the curing speed and curing depth, and uses near-infrared light that is relatively safe for the human body, greatly reducing the radiation to the operators.

[0153] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A cyanine photoinitiator, characterized in that, The cyanine photoinitiator includes a compound having the structure shown in formula (1): In the formula, R1 and R2 are each independently selected from hydrogen, halogen, or together with the carbon atom to which they are attached form a substituted or unsubstituted aryl group; R3 and R4 are each independently selected from hydrogen, halogen, or together with the carbon atom to which they are attached form a substituted or unsubstituted aryl group; X is a halogen atom; Y is selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group; Z is selected from halogen atoms.

2. The cyanine photoinitiator according to claim 1, wherein R1 and R2 are each independently selected from hydrogen or together with the carbon atom to which they are attached form a substituted or unsubstituted monocyclic aromatic hydrocarbon; and / or R3 and R4 are each independently selected from hydrogen or together with the carbon atom to which they are attached form a substituted or unsubstituted monocyclic aromatic hydrocarbon.

3. The cyanine photoinitiator according to claim 1, wherein X is a chlorine atom; Y is selected from a phenyl group or a dimethylamino group; Z is an iodide ion.

4. The cyanine photoinitiator according to claim 1 or 2, characterized in that, The photoinitiator includes one or more of the compounds having the structures shown in the following formula (2) - formula (5):

5. The cyanine photoinitiator according to any one of claims 1-4, characterized in that, The maximum absorption wavelength of the cyanine photoinitiator is in the range of 700nm - 900nm, preferably in the range of 750nm - 850nm.

6. A method for preparing the cyanine photoinitiator according to any one of claims 1-5, characterized in that, Comprising the following steps: Step S1, reflux the compound of formula A, haloethane, and acetonitrile at 80°C - 90°C for 10h - 14h under anaerobic conditions to obtain intermediate I; Step S2, dissolve the compound of formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate, and tetrakis(triphenylphosphine)palladium in a mixed solution of 1,4-dioxane and water, and reflux at 100°C - 110°C for 20h - 24h under anaerobic conditions to obtain intermediate II; Step S3, dissolve intermediate II in a mixed solution of N,N-dimethylformamide and dichloromethane, and then slowly drop phosphorus oxychloride (or phosphorus oxybromide) into the above mixed solution, and reflux at 50°C - 60°C for 4h - 6h under anaerobic conditions to obtain intermediate III; Step S4, dissolve intermediate I and III in a mixed solution of n-butanol and toluene, and reflux at 100°C - 110°C for 4h - 6h under anaerobic conditions to obtain the compound of formula (1), 7. The method according to claim 6, wherein In step S1, the molar ratio of the compound of formula A to haloethane is 1:1 - 1:1.

3.

8. The method according to claim 6, wherein In step S2, the molar ratio of the compound of formula B, 4-(4-bromophenyl)cyclohexanone, potassium carbonate to tetrakis(triphenylphosphine)palladium is 1 - 1.2:1:5:0.

08.

9. The method according to claim 6, wherein In step S2, in the mixed solution of 1,4-dioxane and water, the volume ratio of 1,4-dioxane to water is 3:1 - 4:

1.

10. The method according to claim 6, characterized in that, In step S3, slowly drop phosphorus oxychloride in an ice-water bath.

11. The method according to claim 6, characterized in that, In step S4, the molar ratio of intermediate I to intermediate III is 2:1 - 3:

1.

12. The method according to claim 6, wherein In step S4, in the mixed solution of n-butanol and toluene, the volume ratio of n-butanol to methanol is 7:3 - 7.5:2.

5.

13. Use of the cyanine photoinitiator according to any one of claims 1-5 in a photopolymerization reaction, characterized in that, The photopolymerization reaction includes subjecting the polymerizable monomer and the cyanine photoinitiator to a photopolymerization reaction under irradiation with light having a wavelength of 700nm - 900nm to obtain a photocured product.

14. The use according to claim 13, characterized in that, The addition amount of the cyanine photoinitiator is less than or equal to 0.1% by mass based on the total mass of the polymerization monomers, preferably less than or equal to 0.05%.

15. The use according to claim 13, characterized in that, The photopolymerization reaction further includes mixing the polymerization monomers, the cyanine photoinitiator and the ultraviolet photoinitiator, and then performing a near-infrared photopolymerization reaction under irradiation with light having a wavelength of 700 nm to 900 nm, preferably 770 nm to 810 nm; and then performing ultraviolet photopolymerization under irradiation with light having a wavelength of 340 nm to 380 nm to obtain a photocured product.

16. The use according to any one of claims 13 to 15, characterized in that, The polymerization monomers include one or more of acrylate monomers and styrene monomers.

17. The use according to claim 15, characterized in that, The ultraviolet photoinitiator is selected from one or more of benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

18. The use according to claim 15, wherein The addition amount of the ultraviolet photoinitiator is less than or equal to 0.2% by mass based on the total mass of the polymerization monomers, preferably less than or equal to 0.1%.

19. Use according to any one of claims 13 - 15, characterized in that, The photocured product is used as a lens.

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