Application of novel disubstituted oxygen / thioxanthone efficient visible light initiator in vinyl ether photopolymerization system
By designing novel disubstituted oxygen/thioxanthraquinone photoinitiators, the problem of the need for hydrogen donors in oxygen/thioxanthraquinone photoinitiators was solved, enabling efficient initiation of vinyl ether photopolymerization and improving photocuring efficiency.
Patent Information
- Application Number
- CN202411327434.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-05-22
- Filing Date
- 2024-09-23
- Publication Date
- 2025-11-25
AI Technical Summary
Existing oxo/thioxanthones require the interaction of a hydrogen donor to exhibit good photoinitiation activity, and traditional hydrogen donors are toxic and have an odor, which affects the performance of photocurable products.
A novel class of disubstituted oxygen/thioheterocyclic anthrone visible light initiators was designed, using disubstituted oxygen/thioheterocyclic anthrone as the basic skeleton and incorporating functional acyl groups. The preparation method involves reacting 2,4-disubstituted oxygen/thioheterocyclic anthrone compounds with an excess of acyl chloride compounds in an organic solvent under inert gas protection to obtain highly efficient visible light initiators.
This novel initiator exhibits excellent light absorption performance in the ultraviolet-visible region, enabling it to efficiently initiate the free radical photopolymerization of vinyl ethers with a conversion rate exceeding 70%, thus broadening its application range in free radical photocuring systems.
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Figure CN121005679A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a preparation method of a new type of double-substituted oxygen / sulfur heteroanthracene ketone efficient visible light initiator and its application in a vinyl ether photopolymerization system, and belongs to the field of free radical photoinitiators. BACKGROUND
[0002] Photopolymerization technology is widely used in many fields, such as photocuring coatings, adhesives, inks, microelectronics, 3D printing, photoresists and the like. In the formulation of photopolymerization materials, photoinitiators play an important role. Photoinitiators absorb light energy under light and, through self-interaction or interaction with co-initiators, produce active species to initiate crosslinking polymerization of monomers, playing a decisive role in the photocuring rate. In recent years, visible light initiation systems have attracted great attention due to their safety, no ozone generation and deeper curing depth than ultraviolet light curing.
[0003] Oxygen / sulfur heteroanthracene ketone photoinitiator is the most widely used hydrogen abstraction type photoinitiator, and its main absorption wavelength is 370-385 nm, which can extend to about 450 nm. Due to its maximum absorption spectrum at the junction of ultraviolet and visible light, the main absorption peak can be extended to the visible light region by simple modification of its structure, so as to be used as a visible light initiator, thereby widening its application range. As a typical hydrogen abstraction type photoinitiator, oxygen / sulfur heteroanthracene ketone needs to interact with an external hydrogen donor to exhibit good photoinitiation activity. These hydrogen donors are usually tertiary amines, alcohols, thiols, and ether compounds, which are toxic, odorous and volatile, affecting the performance of photocured products. In order to solve this problem, a class of efficient single-component oxygen / sulfur heteroanthracene ketone visible light initiators containing ether bonds and sulfide bonds has been developed and widely used in free radical and cationic photopolymerization technology. SUMMARY
[0004] The present application takes double-substituted oxygen / sulfur heterocyclic anthracene ketone as the basic conjugated skeleton structure, combines with functional acyl functional groups, and designs a new type of double-substituted oxygen / sulfur heterocyclic anthracene ketone visible light initiator. This visible light initiator has excellent light absorption performance in the ultraviolet-visible light region and exhibits high initiation efficiency for vinyl ether-containing free radical photopolymerization systems.
[0005] The purpose of the present application is achieved by the following scheme: The double-substituted oxygen / sulfur heteroanthracene ketone efficient visible light initiator is used as a photoinitiator for a pre-polymer vinyl ether-containing free radical photopolymerization system, and the double-substituted oxygen / sulfur heteroanthracene ketone efficient visible light initiator takes oxygen / sulfur heteroanthracene ketone as the main skeleton, and the structural formula is as follows: .
[0006] R 1 and R2 is oxygen or sulfur; R 3 including but not limited to one of the following groups: ; R 4 is oxygen or sulfur; R 5 is nitrogen or phosphorus; R 6 is methyl or ethyl.
[0007] The visible light initiator is selected from any one of the following: , , , , ,
[0008] The preparation method of the novel double-substituted oxygen / sulfur heterocyclic anthracene ketone high-efficiency visible light initiator uses 2,4-disubstituted oxygen / sulfur heterocyclic anthracene ketone compounds and acyl chloride compounds as raw materials, and adopts the synthesis route shown in the following formula.
[0009]
[0010] The preparation method comprises the following steps: Under the protection of inert gas, the 2,4-disubstituted oxygen / sulfur heterocyclic anthracene ketone compound is dissolved in an organic solvent, an excess of base is added, an excess of acyl chloride compound organic solution is slowly added dropwise under ice water bath, reaction is carried out at room temperature, TLC is used to detect the completion of the reaction, the reaction is stopped, filtration is carried out, the filtrate is concentrated, and the novel double-substituted heterocyclic anthracene ketone high-efficiency visible light initiator is obtained after purification.
[0011] The 2,4-disubstituted oxygen / sulfur heterocyclic anthracene ketone compound includes but is not limited to the following: .
[0012] wherein R 1 and R 2 is oxygen or sulfur; The sulfonyl chloride compound is R 3 COCl, R 3 including but not limited to one of the following groups: ; wherein R 4 is oxygen or sulfur; R 5 is nitrogen or phosphorus; R 6 is methyl or ethyl.
[0013] The solvent includes but is not limited to ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, N, N-dimethylformamide or N, N-dimethylacetamide; the base includes but is not limited to sodium hydroxide (NaOH), potassium hydroxide (KOH), pyridine, triethylamine ((C2H5)3N), piperidine or pyrrolidine.
[0014] In the preparation method, the reaction of each step is carried out at room temperature.
[0015] The prepared visible light initiator can be selected from any one of 、 、 、 、 、 .
[0016] The novel double-substituted oxygen / sulfur heterocyclic anthracene ketone high-efficiency visible light initiator can be applied to initiate the curing of a prepolymer containing a vinyl ether radical photopolymerization system. The prepolymer containing a vinyl ether polymerization system includes a vinyl ether BDDVE system.
[0017] This novel double-substituted oxygen / sulfur heterocyclic anthracene ketone high-efficiency visible light initiator not only has better solubility in organic solvents and resins, but also has higher polymerization efficiency in a light curing system, thereby widening the application range thereof in a radical light curing system.
[0018] The advantages and beneficial effects of the present application are as follows: The photoinitiation efficiency is high. The photopolymerization kinetics research shows that the novel double-substituted oxygen / sulfur heterocyclic anthracene ketone high-efficiency visible light initiator of the present application can efficiently initiate the polymerization of a radical monomer under the irradiation of an ultraviolet LED lamp. In some embodiments, the conversion rate of the vinyl ether is 70% or more, further preferably 80% or more, further preferably 88% or more, and further preferably 94% or more. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The FT-IR spectrum of 2, 4-di(acetyloxy)thioxanthone prepared in Example 1.
[0020] Figure 2 The FT-IR spectrum of 2, 4-di(acetyloxy)thioxanthone prepared in Example 1. 1 H-NMR spectrum.
[0021] Figure 3 The FT-IR spectrum of 2, 4-di(acetyloxy)thioxanthone prepared in Example 1. 13 C-NMR spectrum.
[0022] Figure 4 The UV-vis spectrum of 2,4-bis(acetoxy)thioxanthonone prepared in Example 1.
[0023] Figure 5 Kinetic curves of BDDVE initiated by 2,4-bis(acetoxy)thionanone prepared in Example 1. Detailed Implementation
[0024] The features and advantages of the present invention can be further understood through the following detailed description in conjunction with the accompanying drawings. The provided embodiments are merely illustrative of the method of the present invention and do not limit the rest of the content disclosed herein in any way.
[0025] Example 1. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 2.50 g (25 mmol) of triethylamine, and 40 mL of anhydrous tetrahydrofuran were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of freshly distilled tetrahydrofuran and 0.20 g (25 mmol) of chloroacetyl were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 3 g of the target compound 1.
[0026] Figures 1-3 The provided FT-IR, 1 H and 13 C10 NMR provided evidence for the structure of target compound 1.
[0027] Appendix Figure 1 The FT-IR spectra appear at 2970 and 2921 cm⁻¹. -1 The absorption peak can be attributed to the characteristic absorption peak of the CH stretching vibration on the benzene ring skeleton in its molecular structure; 1721 cm⁻¹ -1 and 1635 cm -1 The absorption peaks at 1601 and 1437 cm⁻¹ can be attributed to the stretching vibrations of the ester carbonyl group of the acetate ester and the ketone carbonyl group of the thioxanthone in its molecular structure; -1 The characteristic absorption peak for the C=C stretching vibration of the anthracene ring skeleton is located at 1268 cm⁻¹. -1 The peak at this location represents the characteristic peak of the COC stretching vibration of the acetate group.
[0028] Depend on Figure 2In the spectrum, the peaks at 8.2 and 7.4 ppm are the protons of the benzene ring skeleton on both sides of the acetoxy group, the peaks in the range of 7.4-7.7 ppm are the protons of the benzene ring skeleton on the thioxanthone, and the peaks at 2.5 and 2.4 ppm are the methyl protons of the disubstituted acetoxy group.
[0029] Figure 3 In the spectrum, the peak at 173.9 ppm is the carbon peak of C=O in the thioxanthone structure, the peaks at 163.2 and 164.2 ppm are the carbon peaks of O=C in the disubstituted acetoxy group, the peaks at 143.7 and 141.2 ppm are the resonance absorption peaks of two C atoms bonded to adjacent ether bonds in the thioxanthone structure, and the peaks at 16.2 and 16.1 ppm are the methyl absorption peaks in the disubstituted acetoxy group. These results indicate that the target compound 1 has been successfully prepared.
[0030] From the UV-vis spectrum of Figure 4 It can be seen that the maximum absorption wavelength of the target compound 1 is located at 405 nm, which is in the visible light region, and the effective absorption range covers 275-450 nm.
[0031] The Figure 5 The kinetic curve of initiating BDDVE is given. The change of the absorption intensity of a certain characteristic peak during irradiation is recorded by real-time infrared combined with a high-speed recorder. BDDVE is used as the polymerization monomer, and a certain amount of target compound 1 ([PI] = 2×10 -5 mol / g) / BDDVE sample solution is added to the middle of the potassium bromide salt piece to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change of the carbon-carbon double bond absorption peak area is recorded by infrared spectrometer to obtain the conversion rate of the corresponding monomer. The results show that 2, 4-bis(acetoxy)thioxanthone can also successfully initiate the free radical polymerization of polybutyl vinyl ether resin. These photopolymerization experimental results show that 2, 4-bis(acetoxy)thioxanthone is an excellent visible light initiator.
[0032] Example 2. Preparation of visible light initiator 2.60 g (10 mmol) of 2,4-dimercaptoxanthone, 1.00 g (25 mmol) of sodium hydroxide, and 40 mL of anhydrous ethanol were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of anhydrous ethanol and 0.24 g (25 mmol) of chloropropionyl were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 3.7 g of the target compound 2.
[0033] Kinetic application testing of HBVE with vinyl ether group initiated by compound 2: The change in absorption intensity of a characteristic peak under illumination was recorded using real-time infrared spectroscopy and a high-speed recorder. HBVE was used as the polymerization monomer, and target compound 2 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g HBVE sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomeric HBVE was detected to be 70%.
[0034] Example 3. Visible light initiator Preparation 2.60 g (10 mmol) of 2,4-dimercaptoxanthone, 0.20 g (25 mmol) of pyridine, and 40 mL of anhydrous acetone were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of anhydrous acetone and 0.33 g (25 mmol) of furan-2-formyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.91 g of the target compound 3.
[0035] Kinetic application test of vinyl ether CHVE initiated by compound 3: The change in absorption intensity of a characteristic peak under illumination was recorded using real-time infrared spectroscopy and a high-speed recorder. CHVE was used as the polymerization monomer, and target compound 3 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g CHVE sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomer CHVE was detected to be 74%.
[0036] Example 4. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 0.21 g (25 mmol) of piperidine, and 40 mL of anhydrous acetonitrile were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of freshly distilled acetonitrile and 0.37 g (25 mmol) of thiophene-2-formyl chloride were slowly added dropwise over a constant-pressure dropping funnel over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.64 g of the target compound 4.
[0037] Kinetic application testing of the vinyl ether DVE-3 initiated by compound 4: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. DVE-3 was used as the polymerization monomer, and target compound 4 ([PI] = 2 × 10⁻⁶) was added. -5 A sample solution of DVE-3 (mol / g) was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of monomer DVE-3 was detected to be 92%.
[0038] Example 5. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthone, 0.18 g (25 mmol) of tetrahydropyrrole, and 40 mL of N,N-dimethylformamide were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of N,N-dimethylformamide and 0.36 g (25 mmol) of N-methylpyrrole-2-formyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 4.58 g of the target compound 5.
[0039] Kinetic application testing of vinyl ether EVE initiated by compound 5: Real-time infrared spectroscopy combined with a high-speed recorder was used to record the change in absorption intensity of a characteristic peak under illumination. Using EVE as the polymerization monomer, target compound 5 ([PI] = 2 × 10⁻⁶) was added. -5A sample solution of (mol / g) / EVE was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of the monomeric EVE was detected to be 81%.
[0040] Example 6. Visible light initiator Preparation 2.44 g (10 mmol) of 2,4-dihydroxythioxanthrone, 0.14 g (25 mmol) of potassium hydroxide, and 40 mL of N,N-dimethylacetamide were added to a 100 mL single-necked flask. The mixture was purged with argon gas and kept under argon protection. The mixture was stirred in an ice-water bath until completely dissolved. After stirring for 10 min in an ice-water bath, 5 mL of N,N-dimethylacetamide and 0.44 g (25 mmol) of P-methylphosphacyclopentadiene-2-carboxyl chloride were slowly added dropwise using a constant-pressure dropping funnel. The addition was completed over 10 min. The mixture was stirred in an ice-water bath for 2 h, and the reaction was monitored by TLC to confirm completion. The reaction mixture was filtered, diluted with an appropriate amount of ethyl acetate, washed three times with water, and the organic phase was concentrated to obtain 5.20 g of the target compound 6.
[0041] Kinetic application test of vinyl ether BVE initiated by compound 6: The change in absorption intensity of a characteristic peak under illumination was recorded using real-time infrared spectroscopy and a high-speed recorder. BVE was used as the polymerization monomer, and target compound 6 ([PI] = 2×10) was added. -5 A mol / g BVE sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the change in the absorption peak area of the carbon-carbon double bond was recorded using an infrared spectrometer. The conversion rate of monomeric BVE was detected to be 83%.
[0042] The kinetic application test of the vinyl ether BDDVE initiated by the above-prepared compounds 1-6 was carried out: the change in absorption intensity of a certain characteristic peak under illumination was recorded using real-time infrared spectroscopy and a high-speed recorder. Using BDDVE as the polymerization monomer, target compound 1-6 ([PI] = 2 × 10⁻⁶) was added. -5 A mol / g BDDVE sample solution was added dropwise to the center of a potassium bromide salt plate to form a uniform liquid film. After irradiation with LED ultraviolet light for 15 min, the changes in the carbon-carbon double bond absorption peak area were recorded using an infrared spectrometer. The conversion rate distribution of BDDVE monomers is as follows: .
Claims
1. A disubstituted oxy / thioxanthonone high-efficiency visible light initiator is used as a photoacid-generating agent molecule in the photoinitiator of prepolymers containing vinyl ethers in free radical photopolymerization systems. The disubstituted oxy / thioxanthonone high-efficiency visible light initiator has an oxy / thioxanthonone as the main skeleton, and its structural formula is as follows: 。 2. The application according to claim 1, characterized in that, The prepolymer containing vinyl ether polymer systems includes any one of the following vinyl ether systems: BDDVE system, HBVE system, CHVE system, DVE-3 system, EVE system, or BVE system.
3. The application according to claim 1, characterized in that: R 1 For oxygen or sulfur; R 2 For oxygen or sulfur; R 3 Includes, but is not limited to, one of the following groups: .
4. The application according to claim 3, characterized in that: R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
5. A method for preparing a highly efficient visible light initiator of a disubstituted oxy / thioxanthrone class, characterized in that, The preparation method of the visible light initiator includes the following steps: Under inert gas protection, 2,4-disubstituted oxygen / thiocyclic anthrone compounds were dissolved in an organic solvent, excess alkali was added, and excess organic solution of acyl chloride compounds was slowly added dropwise under an ice-water bath. The reaction was carried out at room temperature, and the reaction was stopped by TLC detection. The mixture was then filtered, the filtrate was concentrated, and purified to obtain a novel, highly efficient visible light initiator of disubstituted heterocyclic anthrone compounds.
6. The method for preparing the visible light initiator according to claim 5, characterized in that, The 2,4-disubstituted oxygen / thioheterocyclic anthrone compounds include the following compounds: R 1 For oxygen or sulfur; R 2 It is oxygen or sulfur.
7. The method for preparing the visible light initiator according to claim 6, characterized in that, The acyl chloride compound is R 3 C(O)Cl, R 3 Includes one of the following groups: ;R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
8. The method for preparing the visible light initiator according to claim 5, characterized in that, The organic solvent includes any one of ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or N,N-dimethylacetamide, and the base includes, but is not limited to, sodium hydroxide, potassium hydroxide, pyridine, triethylamine, piperidine or tetrahydropyrrole.
9. The visible light initiator prepared by the method according to any one of claims 5-8, characterized in that, The structural formula is: ;R 1 For oxygen or sulfur; R 2 For oxygen or sulfur; R 3 Includes, but is not limited to, one of the following groups: ;R 4 For oxygen or sulfur; R 5 For nitrogen or phosphorus; R 6 It can be methyl or ethyl.
10. The visible light initiator according to claim 9, characterized in that, The visible light initiator is selected from... , , , , , Any one of them.