Benzophenone carbazolyl chalcone photoinitiator and application thereof

Abstract

The invention provides a benzophenone carbazolyl chalcone photoinitiator and an application of the benzophenone carbazolyl chalcone photoinitiator. The benzophenone carbazolyl chalcone photoinitiator comprises a compound with a structural formula as shown in a formula (I). The benzophenone carbazolyl chalcone provided by the invention can be used as a single-component photoinitiator or can be compounded with other substances to initiate a photopolymerization reaction under visible light, and particularly has a good photoinitiation effect under long-wavelength (preferably 405-470 nm) LED light.

Description

A benzophenone carbazole chalcone photoinitiator and its application Technical Field

[0001] This invention relates to the field of photoinitiators, and more specifically, to a benzophenone carbazole chalcone photoinitiator and its application. Background Technology

[0002] A photoinitiator is a compound that absorbs light energy under illumination of a specific wavelength of light source, generating an active intermediate capable of initiating monomer polymerization. These active intermediates are typically free radicals or cationic compounds, thereby initiating the polymerization and cross-linking reaction of monomers or oligomers. Based on the initiation mechanism, photoinitiators are mainly classified into two categories: free radical and cationic. According to the response wavelength, they can be divided into ultraviolet photoinitiators and visible light photoinitiators. Visible light photoinitiators, due to their advantages such as low energy consumption, high safety, and strong substrate penetration, have become a core direction for industrial upgrading. Meanwhile, LED photopolymerization technology, due to its environmental friendliness, low energy consumption, long lifespan, and instant switching characteristics, is gradually becoming the preferred technology in the field of photocuring. However, LED light sources have a narrow emission band, which contrasts sharply with the wide-spectrum output of traditional mercury lamps, posing a new challenge to the design of photoinitiators—the absorption spectrum of the photoinitiator must be precisely matched with the emission band of the LED light source.

[0003] 1,6-Hexanediol diacrylate, as a typical bifunctional acrylate monomer, plays an important role in the field of photopolymerization. In the photopolymerization of HDDA, the choice of photoinitiator is crucial, determining not only the polymerization rate and final conversion rate but also influencing the microstructure and properties of the material. Traditional HDDA polymerization often uses ultraviolet photoinitiators, but these pose risks of yellowing and migration. Studies have shown that Schiff base photoinitiators (such as TXNI) can efficiently initiate HDDA polymerization under LED light irradiation, exhibiting a faster initiation rate and higher double bond conversion rate; however, Schiff base initiators are unstable in acid and alkali conditions, resulting in relatively poor storage stability. However, existing initiators still face challenges such as significant oxygen inhibition, poor compatibility with some systems, and insufficient efficiency under high-wavelength LED light sources, restricting the application expansion of HDDA in high-end scenarios. Summary of the Invention

[0004] The first objective of this invention is to provide a benzophenone carbazole chalcone photoinitiator, comprising compounds with the structural formula shown in formula (I): Formula (I) in which R is one of the following groups: , .

[0005] The applicant discovered that benzophenone carbazole chalcone with the above-described structure can be used as a photoinitiator and initiates photopolymerization reactions under visible light, especially under long-wavelength (preferably 405 nm to 470 nm) LED light, where the photoinitiation effect is even better. The benzophenone carbazole chalcone photoinitiator provided by this invention can be used as a single-component photoinitiator, and its initiation effect as a single-component photoinitiator is far superior to the initiation effect of the benzophenone LED visible light initiator previously developed by the applicant.

[0006] In a preferred embodiment of the present invention, the benzophenone carbazole chalcone photoinitiator is used for initiation under LED light. The wavelength of the LED light is preferably 405nm~470nm, more preferably 410~470nm. In specific embodiments of the present invention, the wavelength of the LED light can be 405nm, 410nm, 435nm, 450nm, 470nm, etc. The benzophenone carbazole chalcone photoinitiator provided by the present invention exhibits excellent initiation effect under 410nm~470nm LED light.

[0007] In a preferred embodiment of the present invention, R is... The structure of this compound (BPC-DB) is shown in formula (II) below: Formula (II).

[0008] The applicant discovered that using a photoinitiator containing BPC-DB for polymerization reactions initiated by a single component under long-wavelength LED illumination, or in combination with other initiators, resulted in faster initiation speeds and higher conversion rates.

[0009] In an optional embodiment of the present invention, R is... The structure of this compound (BPC-CZ) is shown in formula (III) below: Formula (III).

[0010] The applicant discovered that using a photoinitiator containing BPC-CZ has a good initiation effect under long-wavelength LED illumination.

[0011] Another object of the present invention is to provide the application of benzophenone carbazole chalcone photoinitiator comprising the above structure in photocuring reactions.

[0012] In this invention, the photocuring reaction is a free radical polymerization reaction, a cationic polymerization reaction, or a free radical-cationic polymerization reaction. In specific embodiments of this invention, the monomers for the photocuring reaction may include one or more of the following: acrylate monomers (such as 1,6-hexanediol diacrylate, monofunctional HEA, difunctional PEGDA, trifunctional TMPTA, PETA, fluorinated acrylate monomers, etc.), epoxy monomers, etc. That is, in this invention, the photocuring reaction can be the polymerization reaction of 1,6-hexanediol diacrylate (HDDA), the polymerization reaction of monofunctional HEA (hydroxyethyl acrylate), the polymerization reaction of difunctional PEGDA, the polymerization reaction of trifunctional TMPTA, the polymerization reaction of PETA, the polymerization reaction of fluorinated acrylate monomers, the polymerization reaction of epoxy monomers (such as EPOX), the preparation reaction for photocurable gel electrolytes, the photocuring reaction of mixed acrylate / epoxy monomers, etc. Using the benzophenone carbazole chalcone photoinitiator provided in this invention as an initiator to initiate the above reactions under long-wavelength LED light irradiation all show good reaction effects.

[0013] In a specific embodiment of the present invention, the above polymerization reaction can be initiated by the benzophenone carbazolyl chalcone photoinitiator provided by the present invention alone, or by a combination of the benzophenone carbazolyl chalcone photoinitiator and a co-initiator provided by the present invention; wherein, the co-initiator can be an iodonium salt or a hydrogen donor amine (for example, ethyl 4-dimethylaminobenzoate).

[0014] In a preferred embodiment of the present invention, the molar ratio of the photoinitiator to the mass ratio of the polymer monomer is preferably no greater than 5 × 10⁻⁶. -6 mol / g, further preferably not greater than 2.5 × 10 mol / g. -6 mol / g. When a co-initiator is used in the co-initiator, the preferred molar ratio of photoinitiator to co-initiator is 1:(5~10).

[0015] In an optional embodiment of the present invention, the light intensity of the photocuring reaction can be 100~250mW / cm². 2 For example, it can be 130mW / cm 2 140mW / cm 2 150mW / cm 2 200mW / cm 2 220mW / cm 2 wait.

[0016] In an optional embodiment of the present invention, the photocuring reaction can be a polymerization reaction of 1,6-hexanediol diacrylate (HDDA). Preferably, the molar ratio of the photoinitiator to the mass ratio of the monomer is no greater than 5 × 10⁻⁶. -6mol / g, further preferably not greater than 2.5 × 10 mol / g. -6 mol / g. That is, in the preferred embodiment, only the above-mentioned amount of photoinitiator is needed to achieve the excellent initiation effect described in this invention.

[0017] In specific embodiments of the present invention, the polymerization reaction of HDDA can be initiated solely by the aforementioned benzophenone carbazole chalcone photoinitiator, or by a combination of the aforementioned benzophenone carbazole chalcone photoinitiator and an iodonium salt or a hydrogen donor amine (i.e., the co-initiator is an iodonium salt or a hydrogen donor amine). When using an iodonium salt as a co-initiator, the molar ratio of the photoinitiator provided by the present invention to the iodonium salt (preferably bis-tert-butylphenyl iodonium hexafluorophosphate) is preferably 1:(5-10). When using a hydrogen donor amine as a co-initiator in combination with the photoinitiator provided by the present invention, the molar ratio of the photoinitiator provided by the present invention to the hydrogen donor amine (ethyl 4-dimethylaminobenzoate EDB) is preferably 1:(5-10). A high EDB ratio will cause yellowing of the sample, while a low EDB ratio will result in a slow initiation rate.

[0018] In an optional embodiment of the present invention, the photocuring reaction can also be a cationic polymerization reaction, such as an EPOX polymerization reaction. Preferably, the molar ratio of the photoinitiator to the mass ratio of the monomer is no greater than 5 × 10⁻⁶. -6 mol / g, further preferably not greater than 2.5 × 10 mol / g. -6 mol / g. That is, in the preferred embodiment, only the above-mentioned amount of photoinitiator is needed to achieve the excellent initiation effect described in this invention. When using the above-mentioned benzophenone carbazole chalcone photoinitiator and co-initiator (preferably iodonium salt) in combination for initiation, the molar ratio of photoinitiator to co-initiator (preferably iodonium salt) is preferably 1:(5~10).

[0019] In an optional embodiment of the present invention, the photocuring reaction can also be a hybrid photocuring reaction, such as an EPOX / TMPTA polymerization reaction. Preferably, the molar ratio of the photoinitiator to the mass ratio of the monomer is no greater than 5 × 10⁻⁶. - 6 mol / g, further preferably not greater than 2.5 × 10 mol / g. -6mol / g. In the preferred embodiment, only the above-mentioned amount of photoinitiator is needed to achieve the excellent initiation effect described in this invention. In the EPOX / TMPTA polymerization reaction, the molar ratio of EPOX to TMPTA can be arbitrary, meaning the photoinitiator provided by this invention can be used to initiate EPOX / TMPTA polymerization reactions with any monomer ratio. When using the above-mentioned benzophenone carbazole chalcone photoinitiator and co-initiator (preferably iodonium salt) in combination for initiation, the preferred molar ratio of photoinitiator to co-initiator is 1:(5~10). Within this preferred range, the initiation effect is optimal.

[0020] The benzophenone carbazole chalcone photoinitiator provided by this invention is a novel photoinitiator that exhibits excellent initiation performance under visible light. It also demonstrates good initiation performance when used as a single-component photoinitiator. Compared to existing photoinitiators, the photoinitiator provided by this invention is more suitable for long-wavelength (405nm~470nm) LED photoinitiation. When using the benzophenone carbazole chalcone photoinitiator provided by this invention to initiate polymerization, the photoinitiation speed is fast, the molar extinction coefficient is higher, and the initiation effect is further improved. Attached Figure Description

[0021] Figure 1 shows the 1H NMR spectrum of the benzophenone carbazole chalcone photoinitiator BPC-DB obtained in Example 1; Figure 2 shows the 1C NMR spectrum of the benzophenone carbazole chalcone photoinitiator BPC-DB obtained in Example 1; Figure 3 shows the infrared spectrum of the benzophenone carbazole chalcone photoinitiator BPC-DB obtained in Example 1; Figure 4 shows the high-resolution mass spectrum of the benzophenone carbazole chalcone photoinitiator BPC-DB obtained in Example 1; where the upper figure represents experimental values ​​and the lower figure represents theoretical values; Figure 5 shows the NMR spectrum of the benzophenone carbazole chalcone photoinitiator BPC-CZ obtained in Example 2. Figure 6 shows the 1H NMR spectrum of the benzophenone carbazole chalcone photoinitiator BPC-CZ obtained in Example 2; Figure 7 shows the infrared spectrum of the benzophenone carbazole chalcone photoinitiator BPC-CZ obtained in Example 2; Figure 8 shows the high-resolution mass spectra of the benzophenone carbazole chalcone photoinitiator BPC-CZ obtained in Example 2; where the upper figure represents experimental values ​​and the lower figure represents theoretical values; Figure 9 shows the UV-Vis absorption spectra of photoinitiators BPC-DB, BPC-CZ, and BPC; Figure 10 shows the UV-Vis absorption spectra of photoinitiators BPC-DB, BPC-CZ, and BPC at LED@ Figure 11 shows the time-double bond conversion curves of the HDDA reaction initiated by photoinitiators BPC-DB, BPC-CZ, and BPC under LED @ 435nm (a) illumination in the presence of EDB, and the time-double bond conversion curves of photoinitiators BPC-DB and BPC-CZ under LED @ 450nm (b) and 470nm (c) illumination in the presence of Iod, and the time-double bond conversion curves of the HDDA reaction initiated by photoinitiators BPC-DB, BPC-CZ, and BPC under LED @ 450nm (b) and 470nm (c) illumination in the presence of Iod, and the time-double bond conversion curves of the HDDA reaction initiated by photoinitiators BPC-DB, BPC-CZ, and BPC under LED @ 405nm (a) and 435nm (b) illumination in the presence of EDB. Figure 13 shows the time-double bond conversion curves of the HDDA reaction initiated under 450nm (c) illumination, and the time-double bond conversion curves of the HDDA reaction initiated by photoinitiators BPC-DB and BPC-CZ under LED@470nm (d) illumination. Figure 14 shows the time-epoxy conversion curves of the EPOX reaction initiated by photoinitiators BPC-DB, BPC-CZ, and BPC under LED@405nm illumination in the presence of Iod. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0023] Example 1 The preparation method of the benzophenone carbazole chalcone photoinitiator BPC-DB as shown in structural formula (II) includes the following steps: (1) Synthesis of 3-acetyl-6-benzoyl-N-ethylcarbazole Take a 250 mL three-necked flask, weigh 5.27 g (0.027 mol) of N-ethylcarbazole, and add 150 mL of dichloromethane (DCM) and 3.6 g (0.027 mol) of aluminum trichloride. Then add 3.13 mL of benzoyl chloride and stir the reaction at room temperature for 12 h. Quench with water, let stand to separate the layers, take the organic layer, adsorb it with activated carbon, filter, concentrate it, and obtain a white substance (BPC). The structural formula of BPC is shown in formula (IV) below: Formula (IV).

[0024] Take 2.2 g (7.36 mmol) of BPC in a three-necked flask, add 25 mL of 1,2-dichloroethane (DCE), 5.8 g (43.5 mmol) of aluminum trichloride, add 2 mL of acetyl chloride, stir at room temperature for 12 h, quench with water, wash with water and separate the layers three times, concentrate the organic layer to obtain 3-acetyl-6-benzoyl-N-ethylcarbazole.

[0025] (2) The synthesis steps of BPC-DB were as follows: 0.341 g (1 mmol) of 3-acetyl-6-benzoyl-N-ethylcarbazole, 0.273 g (1 mmol) of 4-diphenylaminobenzaldehyde, 0.4 g (10 mmol) of NaOH and 25 mL of EtOH were added to a 100 mL single-necked flask. The mixture was stirred continuously at room temperature for two days, filtered, and the filter cake was washed with ethanol and dried under vacuum to obtain the product, yellow crystals, namely (E)-3-(4-(diphenylamino)phenyl)-1-(N-ethylcarbazolyl)propenone (BPC-DB).

[0026] The proton NMR spectrum of the product obtained in this embodiment is shown in Figure 1. The proton NMR spectrum data are as follows: 1H NMR (500MHz, CDCl3): δ ppm, 1.46-1.56(3H, CH3, t, J=7.5Hz), 4.38-4.65(2H, CH2, q, J=7.5Hz), 7.03-7.07 (2H, d, J=8.5Hz), 7.08-7.13 (2H, t, J=7.5Hz ), 7.13-7.18(4H, d, J=8.0Hz ), 7.27-7.33 (4H, t, J=8.0Hz ), 7.49-7.65 (8H, m), 7.80-7.89(m, 3H), 8.07-8.12 (d, 1H, J=8.5Hz ), 8.24-8.29 (1H, d, J=8.5Hz), 8.66 (1H, s), 8.81 (1H, s).

[0027] The carbon NMR spectrum of the product obtained in this embodiment is shown in Figure 2. The carbon NMR spectrum data is as follows: 13 C NMR (500MHz, CDCl3): δ ppm, 196.48, 189.42, 150.02, 146.93, 143.98, 143.25,138.75, 131.94, 130.04, 129.95, 129.74, 129.60, 129.51, 129.01, 128.35,128.22, 127.43, 126.33, 125.43, 124.24, 124.05, 123.06, 122.88, 122.11,121.77, 119.54, 108.90, 108.74, 38.25, 13.93.

[0028] The infrared spectrum of the product obtained in this embodiment is shown in Figure 3, and the high-resolution mass spectrometry spectrum is shown in Figure 4. In Figure 4, the theoretical HRMS value of BPC-DB ([M+Na)) is shown. + The value (m / z 619.2356) matches the experimental value (m / z 619.2356), confirming the successful synthesis of the target structure.

[0029] Example 2: The preparation method of the benzophenone carbazole chalcone photoinitiator BPC-CZ as shown in structural formula (III) includes the following steps: 0.341 g (1 mmol) of the prepared raw material 3-acetyl-6-benzoyl-N-ethylcarbazole was weighed into a 100 mL round-bottom flask, and 0.223 g (1 mmol) of 3-formaldehyde-N-ethylcarbazole, 0.4 g (10 mmol) of NaOH and 25 mL of EtOH were added. The mixture was stirred continuously at room temperature for 1 day, filtered, and the filter cake was washed with ethanol and dried under vacuum to obtain the product yellow crystals, which yielded (E)-1-(6-benzoyl-N-ethylcarbazole)-3-(N-ethylcarbazole)propenone (BPC-CZ).

[0030] The proton NMR spectrum of the product obtained in this embodiment is shown in Figure 5. The proton NMR spectrum data are as follows: 1 H NMR (500MHz, CDCl3): δ ppm, 1.44-1.49 (3H, CH3, t, J=7.5Hz), 1.50-1.56 (3H, CH3, t,J=7.5Hz), 4.35-4.42 (2H, NCH2, q, J=7.5Hz), 4.43-4.51 (2H, NCH2, q, J=7.5Hz),7.27-7.32 (1H, td, J1=0.5 Hz, J2=7.0 Hz), 7.41-7.46 (2H, d, J=8.5 Hz), 7.48-7.58 (5H, m), 7.60-7.66 (1H, tt, J1=1.0Hz, J2=8.5Hz), 7.77-7.83 (1H, d, J=15.5Hz), 7.83-7.90 (3H, m), 8.08-8.11(1H, dd, J1=2.0 Hz, J2=7.5Hz), 8.11-8.16(1H, d, J=15.5 Hz), 8.17-8.20 (1H, d, J=7.5Hz), 8.31-8.36 (dd, 1H, J1=1.5Hz,J2=8.5Hz), 8.41-8.45 (d, 1H, J=1.0Hz), 8.70-8.74 (d, J=1.5 Hz), 8.87-8.90(1H,d, J=1.5 Hz).

[0031] The carbon NMR spectrum of the product obtained in this embodiment is shown in Figure 6. The carbon NMR spectrum data are as follows: 13C NMR (500MHz, CDCl3): δ ppm, 196.53, 189.44, 145.78, 143.28, 141.42, 140.50,138.77, 131.92, 131.19, 129.96, 129.56, 129.03, 128.35, 127.51, 126.48,126.32, 126.21, 124.25, 123.52, 123.07, 122.98, 122.94, 122.13, 121.59,120.77, 119.68, 119.01, 108.90, 108.68, 38.25, 37.81, 13.94.

[0032] The infrared spectrum of the product obtained in this embodiment is shown in Figure 7, and the high-resolution mass spectrometry spectrum is shown in Figure 8. In Figure 8, the theoretical HRMS value of BPC-CZ ([M+Na)) is shown. + The value (m / z 569.2199) matches the experimental value (m / z 569.2199), confirming the successful synthesis of the target structure.

[0033] Experimental Example 1: UV-Vis absorption spectra of photoinitiators. BPC-DB from Example 1 and BPC-CZ from Example 2 were dissolved in tetrahydrofuran to prepare a solution with a concentration of 2.5 × 10⁻⁶. - 5 Prepare a 10 mol / L solution by dissolving BPC in tetrahydrofuran. -4 The UV-Vis absorption spectrum of the mol / L solution was measured using a UV-Vis spectrophotometer, and the data are shown in Figure 9.

[0034] 2. In a specific embodiment of this invention, the yield of HDDA polymerization initiated by a photoinitiator is calculated as: (Actual product mass / Theoretical mass) * 100%. The formulas for calculating the double bond and epoxy conversion rates are as follows: Where A0 is the peak area of ​​the carbon-carbon double bond or epoxy group when the illumination time is 0; A t This represents the peak area of ​​carbon-carbon double bonds or epoxy groups when the illumination time is t.

[0035] 1) Preparation of the single-component photoinitiator system sample: Photoinitiators BPC-DB, BPC-CZ, and BPC (2.5 × 10⁻⁶) were weighed sequentially using a 1 / 10,000 analytical balance. -5 10.00 g of 1,6-hexanediol diacrylate (HDDA) was transferred to a 15 mL centrifuge tube and sonicated until homogeneous. The mass of the photoinitiator in the different systems was as follows: BPC-DB: 0.0149 g; BPC-CZ: 0.0137 g; BPC: 0.0075 g.

[0036] Steps for real-time infrared spectroscopy detection of photoinitiation kinetics: The above samples were subjected to real-time infrared spectroscopy under clamping conditions to detect their photocuring kinetics. The light source was an LED at 405nm with an illumination intensity of 150mW / cm². 2 LED at 435nm, illuminance of 140 mW / cm² 2 LED at 450nm, illuminance of 220 mW / cm² 2 LED at 470nm, illuminance of 200mW / cm² 2 The conversion-time curves of the carbon-carbon double bonds of acrylate monomers as a function of time are shown in Figure 10.

[0037] As shown in Figure 10, BPC-DB exhibits the fastest initiation rate and conversion rate under LED @ 405, 435, 450, and 470 nm conditions, followed by BPC-CZ, with BPC being the slowest. At LED @ 435 nm, the conversion rates after 5 minutes are 21% (BPC-DB), 6% (BPC-CZ), and 3% (BPC), respectively. At LED @ 450 nm or LED @ 470 nm, BPC shows no initiation activity, while BPC-DB can initiate HDDA polymerization, with a double bond conversion rate of approximately 15% after 5 minutes.

[0038] 2) Preparation of the two-component photoinitiator system sample: Weigh the photoinitiator (2.5 × 10⁻⁶) sequentially using a 1 / 10,000 analytical balance. -5 0.1076 g (2×10⁻⁶ mol), bis(tert-butylphenyl)iodonium hexafluorophosphate (Iod) -4 0.0985 g (5 × 10⁻⁶ mol) or ethyl 4-dimethylaminobenzoate (EDB) -4 Transfer 10.00 g of 1,6-hexanediol diacrylate (HDDA) to a 15 mL centrifuge tube and sonicate to mix thoroughly. The mass of photoinitiator BPC-DB in the BPC-DB / Iod or BPC-DB / EDB system is 0.0149 g; the mass of photoinitiator BPC-CZ in the BPC-CZ / Iod or BPC-CZ / EDB system is 0.0137 g; and the mass of photoinitiator BPC in the BPC / Iod or BPC / EDB system is 0.0075 g.

[0039] Steps for real-time infrared spectroscopy detection of photoinitiation kinetics: The photocuring kinetics of the above samples were detected using real-time infrared spectroscopy, with LED at 435nm and illumination intensity of 140 mW / cm². 2 LED at 450nm, illuminance of 220 mW / cm² 2LED at 470nm, illuminance of 200mW / cm² 2 The conversion-time curves of the carbon-carbon double bonds of acrylate monomers as a function of time are shown in Figures 11 and 12, respectively.

[0040] As shown in Figure 11, under the condition of EDB presence (without Iod), BPC still has no initiation activity at LED@435nm (Figure (a)). At this time, BPC-DB has the best initiation effect, followed by BPC-CZ. Under LED@450nm illumination (Figure (b)), BPC-DB and BPC-CZ still have high initiation activity. Under LED@470nm illumination (Figure (c)), BPC-DB has a better initiation effect than BPC-CZ.

[0041] As shown in Figure 12, in the presence of Iod (without EDB), at LED@405nm, BPC-DB exhibits better initiation performance than BPC-CZ, and BPC-CZ exhibits better initiation performance than BPC. Under LED@435nm and LED@450nm illumination, BPC-DB and BPC-CZ show high initiation activity, while the BPC system shows no initiation activity. Furthermore, under LED@450nm illumination, from 0 to 30s, BPC-DB shows better initiation performance than the BPC-CZ system. After 30s, the initiation activity (double bond conversion rate) of the BPC-CZ system is even better than that of BPC-DB. Under LED@470nm conditions, the photoinitiation activity of BPC-DB is better than that of BPC-CZ.

[0042] 3. Polymerization reaction of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (EPOX) 1) Preparation of cationic photoinitiator system sample: Weigh the photoinitiator (2.5 × 10⁻⁶) sequentially using a 1 / 10,000 analytical balance. -5 0.1076 g (2×10⁻⁶ mol), bis(tert-butylphenyl)iodonium hexafluorophosphate (Iod) -4 Transfer 10.00 g of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (EPOX) to a 15 mL centrifuge tube and sonicate to mix thoroughly. The mass of the photoinitiator in the different systems is as follows: BPC-DB: 0.0149 g; BPC-CZ: 0.0137 g; BPC: 0.0075 g.

[0043] Real-time infrared spectroscopy for photoinitiation kinetics: The above samples were subjected to real-time infrared spectroscopy to detect their photocuring kinetics in air, with LEDs at 405nm and illumination intensity of 150mW / cm². 2The conversion-time curves of epoxy monomer functional groups as a function of time are shown in Figure 13. Figure 13 shows that in the EPOX cationic polymerization reaction, BPC-DB exhibits the fastest photoinitiation rate, followed by BPC-CZ, while the BPC system shows the slowest photoinitiation rate compared to the control system. Furthermore, within the range of 0–185 s, the initiation effects of both the BPC-DB and BPC-CZ systems are superior to the BPC system (BPC-DB system shows the fastest photoinitiation rate, followed by BPC-CZ system, and the BPC system shows the slowest).

[0044] 2) Preparation of samples for the hybrid photoinitiator system (EPOX / TMPTA polymerization reaction): Weigh the photoinitiator (2.5 × 10⁻⁶) sequentially using a 1 / 10,000 analytical balance. -5 0.1076 g (2×10⁻⁶ mol), bis(tert-butylphenyl)iodonium hexafluorophosphate (Iod) -4 Transfer the mol) to a 15 mL centrifuge tube. Weigh 5.00 g of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (EPOX) and 5 g of trimethylolpropane triacrylate (TMPTA) into this centrifuge tube, and sonicate to mix thoroughly. The mass of the photoinitiator in the different systems is as follows: BPC-DB: 0.0149 g; BPC-CZ: 0.0137 g; BPC: 0.0075 g.

[0045] Real-time infrared spectroscopy for photoinitiation kinetics: The photocuring kinetics of the above samples were detected in air using real-time infrared spectroscopy, with LED at 405nm and illumination intensity of 150mW / cm². 2 The test results are shown in Figure 14, where the solid line represents the carbon-carbon double bond conversion rate in TMPTA, and the dashed line represents the epoxy functional group conversion rate in EPOX. Figure 14 shows that the BPC-DB photoinitiation system exhibits the best performance, the fastest initiation speed, and the highest monomer conversion rate.

[0046] Finally, the method of this invention is merely a preferred embodiment and is not intended to limit the scope of protection of this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A benzophenone carbazole chalcone photoinitiator, characterized in that, Including compounds with the structural formula shown in formula (I): Equation (I) in which, R is one of the following groups: 、 。 2. The benzophenone carbazole chalcone photoinitiator according to claim 1, characterized in that, The R is 。 3. The benzophenone carbazole chalcone photoinitiator according to claim 1, characterized in that, The benzophenone carbazole chalcone photoinitiator initiates polymerization under LED light.

4. The benzophenone carbazole chalcone photoinitiator according to claim 3, characterized in that, The wavelength of the LED light is 405nm~470nm.

5. The benzophenone carbazole chalcone photoinitiator according to any one of claims 1 to 4, characterized in that, The benzophenone carbazole chalcone photoinitiator is a single-component photoinitiator.

6. The use of the benzophenone carbazole chalcone photoinitiator according to any one of claims 1 to 5 in photocuring reactions.

7. The application according to claim 6, characterized in that, The molar ratio of the photoinitiator to the polymer monomer is no greater than 5 × 10⁻⁶. -6 mol / g.

8. The application according to claim 6, characterized in that, The photocuring reaction is a free radical polymerization reaction, a cationic polymerization reaction, or a free radical-cationic polymerization reaction.

9. The application according to claim 6, characterized in that, The monomers used in the photocuring reaction include acrylate monomers and / or epoxy monomers.

10. The application according to claim 9, characterized in that, The polymerization reaction of the acrylate monomers is initiated by the benzophenone carbazolyl chalcone photoinitiator alone, or by a combination of the benzophenone carbazolyl chalcone photoinitiator and a co-initiator; the co-initiator is an iodonium salt or a hydrogen donor amine.

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