阅读说明：本技术 一种适用于uv-led有氧光固化的含供氢体硫醚型萘酰亚胺衍生物类光引发剂 (Thioether type naphthalimide derivative photoinitiator containing hydrogen donor and suitable for UV-LED aerobic light curing ) 是由 孙芳 胡修远 于 2020-05-18 设计创作，主要内容包括：本发明公开一种适用于UV-LED有氧光固化的含供氢体硫醚型萘酰亚胺衍生物类光引发剂,涉及感光高分子领域,基于现有的光引发剂在UV-LED光源的照射下,在氧气存在的条件下引发性能较差的问题而提出的；本发明制备了一类含供氢体硫醚型萘酰亚胺衍生物类光引发剂,并提供上述含供氢体硫醚型萘酰亚胺衍生物类光引发剂的制备方法及其在光固化体系中的应用；本发明的有益效果在于：①本发明制备的光引发剂的紫外吸收波长明显延长,在LED光源波长范围内,具有较好的紫外吸收能力。②本发明制备的光引发剂的抗氧阻聚效果明显。③本发明制备的光引发剂其迁移稳定性明显提高。(The invention discloses a thioether type naphthalimide derivative photoinitiator containing a hydrogen donor, which is suitable for UV-LED aerobic light curing, relates to the field of photosensitive polymers, and is provided based on the problem that the initiation performance of the existing photoinitiator is poor under the irradiation of a UV-LED light source and in the presence of oxygen; the invention prepares a photoinitiator containing hydrogen donor thioether type naphthalimide derivative, and provides a preparation method and application thereof in a photocuring system; the invention has the beneficial effects that: the ultraviolet absorption wavelength of the photoinitiator prepared by the invention is obviously prolonged, and the photoinitiator has better ultraviolet absorption capacity in the wavelength range of an LED light source. ② the photoinitiator prepared by the invention has obvious antioxidant and polymerization inhibition effects. The migration stability of the photoinitiator prepared by the invention is obviously improved.)

1. The hydrogen donor-containing thioether type naphthalimide derivative photoinitiator suitable for UV-LED aerobic light curing is characterized in that the structural formula of the hydrogen donor-containing thioether type naphthalimide derivative photoinitiator is as follows:

wherein the value range of n is 1-10; preferably, the value range of n is 1-5; most preferably, n has a value of 1; r₁Is selected from C₃-C₂₀Aliphatic alkyl, hydroxy, ethenyl, propenyl, methyl, ethyl, alkoxy, halogen atom, aralkyl or phenyl, preferably R₁Is vinyl or methyl; r₂Selected from the group consisting of carboxy, benzoyl, acetyl, acryloyl, methoxy, ethoxy, nitro, preferably R₂Is methoxy.

2. The method for preparing the photoinitiator containing the hydrogen donor thioether type naphthalimide derivative and suitable for the aerobic photocuring of the UV-LED as claimed in claim 1 is characterized in that the general synthetic process is as follows:

3. the method for preparing the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 2, wherein the method comprises the following steps: the preparation method of the photoinitiator comprises the following steps:

(1) in the step a, adding primary amine and 4-bromo-1, 8-naphthalic anhydride into a reaction vessel, and reacting for 24 hours at 60-100 ℃; after the reaction is finished, cooling, and then washing the crude product with absolute ethyl alcohol for multiple times to obtain a brownish red solid intermediate product A;

(2) in the step b, adding the intermediate product A, acyl chloride and organic base into a reaction vessel, adding an anhydrous organic solvent, and reacting for 6 hours at 0-5 ℃; after the reaction is finished, carrying out reduced pressure distillation to remove the anhydrous organic solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a light yellow solid intermediate product B;

(3) in the step c, adding benzylmercaptan, acetic anhydride and a catalyst into a reactor, heating and refluxing for 12 hours, and stirring; after the reaction is finished, cooling, extracting by dichloromethane, combining organic layers, washing the organic layers by using a carbonate aqueous solution with a certain concentration respectively, then washing by using deionized water, drying the organic layers by using a drying agent, filtering, distilling under reduced pressure to remove a solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a colorless liquid intermediate product C;

(4) in the step d, mixing the intermediate product B prepared in the step B, the intermediate product C prepared in the step C, a palladium catalyst, an iron complex and an inorganic base, adding a proper amount of an organic solvent 1 and an organic solvent 2, and reacting for 24 hours at 80-120 ℃ in a nitrogen atmosphere; and after the reaction is finished, cooling, pouring the reaction solution into a proper amount of saturated salt solution for washing, then extracting with dichloromethane, combining organic phases, washing an organic layer with saturated saline, drying the organic layer with a drying agent, filtering, distilling under reduced pressure to remove the solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a final product.

4. The method for preparing a hydrogen donor sulfide-containing naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 3, wherein in the step a, the mole number of the primary amine is 1-10 times that of 4-bromo-1, 8-naphthalic anhydride, preferably the mole number of the primary amine is 3-6 times that of 4-bromo-1, 8-naphthalic anhydride, and most preferably the mole number of the primary amine is 5 times that of 4-bromo-1, 8-naphthalic anhydride; the reaction temperature is 70-90 ℃, and the preferable reaction temperature is 85 ℃.

5. The method for preparing the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 3, wherein the method comprises the following steps: in the step b, the acyl chloride is one or more selected from acetyl chloride, acryloyl chloride, methacryloyl chloride, benzoyl chloride, terephthaloyl chloride, oxalyl chloride and p-toluenesulfonyl chloride, preferably, the acyl chloride is acetyl chloride and acryloyl chloride; the mole number of the acyl chloride is 1-6 times of that of the intermediate product A, preferably 2-4 times of that of the intermediate product A, and most preferably 3 times of that of the intermediate product A; the organic base is one or more selected from triethylamine, diethylamine, 4-dimethylamino pyridine, 3-methylpyridine and 2-methylpyridine, and the preferable organic base is triethylamine; the mole number of the organic base is 1-7 times of that of the intermediate product A; the mole number of the organic base is preferably 2-5 times that of the intermediate product A, and the mole number of the organic base is most preferably 4 times that of the intermediate product A; the anhydrous organic solvent is one or more selected from anhydrous dichloromethane, anhydrous ethanol, anhydrous petroleum ether, anhydrous acetone, anhydrous toluene and anhydrous tetrahydrofuran, and preferably the organic solvent is anhydrous dichloromethane; the reaction temperature is 0-2 ℃, and the preferable reaction temperature is 0 ℃.

6. The method for preparing the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 3, wherein the method comprises the following steps: in the step c, the mole number of the acetic anhydride is 0.5 to 4.5 times that of the benzylthiol, preferably the mole number of the acetic anhydride is 1.5 to 2.5 times that of the benzylthiol, and most preferably the mole number of the acetic anhydride is 2.0 times that of the benzylthiol; the catalyst is one or more of ferric chloride, ferrous chloride, cupric chloride, cuprous chloride, nickel chloride, aluminum chloride, sodium nitrate, potassium nitrate and magnesium nitrate, and the preferred catalyst is nickel chloride; the mole number of the catalyst is 0.001-0.020 times of that of the benzylmercaptan, preferably the mole number of the catalyst is 0.008-0.012 times of that of the benzylmercaptan, and most preferably the mole number of the catalyst is 0.010 times of that of the benzylmercaptan; the carbonate aqueous solution is one or more of a sodium carbonate aqueous solution, a potassium carbonate aqueous solution, an ammonium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a potassium bicarbonate aqueous solution and an ammonium bicarbonate aqueous solution; preferably, the carbonate aqueous solution is sodium bicarbonate aqueous solution; the concentration of the carbonate aqueous solution is 1-25%, and the concentration of the carbonate aqueous solution is preferably 9-12%; most preferably, the concentration of the aqueous carbonate solution is 10%.

7. The method for preparing the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 3, wherein the method comprises the following steps: in the step d, the palladium catalyst is one or more selected from bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, bis (triphenylphosphino) palladium acetate, bis (di-tert-butylphosphine) palladium dichloride and bis (3,5,3',5' -dimethoxydibenzylideneacetone) palladium, and preferably the palladium catalyst is bis (dibenzylideneacetone) palladium; the iron complex is selected from one or more of 1,1 '-bis (diphenylphosphino) ferrocene, 1-bis diphenylphosphino ferrocene nickel chloride, and (S, S) - (-) -2,2' -bis [ - (N, N-dimethylamino) (phenyl) methyl ] -1,1 '-bis (diphenylphosphino) ferrocene, preferably the iron complex is 1,1' -bis (diphenylphosphino) ferrocene; the inorganic base is selected from one or more of sodium hydroxide, calcium hydroxide, aluminum hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide and anhydrous tripotassium phosphate, and preferably the inorganic base is the anhydrous tripotassium phosphate; the mole number of the palladium catalyst is 0.1-0.8 times of that of the intermediate product B, preferably the mole number of the palladium catalyst is 0.3-0.7 times of that of the intermediate product B, and most preferably the mole number of the palladium catalyst is 0.6 times of that of the intermediate product B; the mole number of the iron complex is 0.10-0.20 times that of the intermediate product B, preferably the mole number of the iron complex is 0.12-0.18 times that of the intermediate product B, and most preferably the mole number of the iron complex is 0.14 times that of the intermediate product B; the mole number of the inorganic base is 1.0-5.0 times of that of the intermediate product B, preferably the mole number of the inorganic base is 2.0-3.0 times of that of the intermediate product B, and most preferably the mole number of the inorganic base is 2.4 times of that of the intermediate product B; the mole number of the intermediate product C is 1-5 times that of the intermediate product B, preferably 2-3 times that of the intermediate product B, and most preferably 3 times that of the intermediate product B; the reaction temperature is 90-115 ℃, and the preferable reaction temperature is 110 ℃; the organic solvent 1 and the organic solvent 2 are the same or different and are respectively and independently selected from one or more of toluene, dichloromethane, methanol, acetone, petroleum ether, ethyl acetate and ethanol; preferably, the organic solvent 1 is toluene, and the organic solvent 2 is acetone; the volume of the organic solvent 1 is 1-6 times of that of the organic solvent 2, preferably the volume of the organic solvent 1 is 2-4 times of that of the organic solvent 2, and most preferably the volume of the organic solvent 1 is 2 times of that of the organic solvent 2; the total volume of the organic solvent 1 and the organic solvent 2 is 1-24 mL, preferably the total volume of the organic solvent 1 and the organic solvent 2 is 5-17 mL, and most preferably the total volume of the organic solvent 1 and the organic solvent 2 is 12 mL; the saturated salt solution is selected from one or more of a saturated ammonium chloride solution, a saturated ammonium sulfate solution, a saturated magnesium chloride solution, a saturated sodium sulfate solution, a saturated potassium chloride solution and a saturated potassium nitrate solution, and preferably the saturated salt solution is the saturated ammonium chloride solution.

8. The method for preparing the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator suitable for UV-LED aerobic photo-curing according to claim 3, wherein the method comprises the following steps: in the steps b and c, the drying agent is one or more selected from anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous magnesium chloride and anhydrous calcium chloride, and preferably, the drying agent is anhydrous sodium sulfate.

9. A free radical photo-curable composition comprising the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator according to claim 1, wherein the photoinitiator is suitable for UV-LED aerobic photo-curing; the composition comprises 0.1 to 5 percent of the photoinitiator containing the hydrogen donor thioether type naphthalimide derivative and 95 to 99.9 percent of light-cured resin or monomer based on the total weight of the composition.

10. The composition of claim 9, wherein the photo-curable resin is selected from one or more of epoxy (meth) acrylic resins, polyurethane (meth) acrylic resins, polyester (meth) acrylic resins, polyether (meth) acrylic resins, acrylated poly (meth) acrylic resins; the monomer is one or more of monofunctional or polyfunctional (methyl) acrylate.

Technical Field

The invention relates to the field of photosensitive polymers, in particular to a preparation method and application of a hydrogen donor-containing thioether type naphthalimide derivative photoinitiator suitable for UV-LED (ultraviolet-light emitting diode) aerobic light curing.

Background

The UV light curing technology is a novel technology appeared in the middle of the 20 th century, and is a process for initiating a liquid substance with chemical reaction activity to be quickly converted into a solid by using ultraviolet light (the wavelength is 200-400nm) as an energy source. Compared with the traditional heat curing technology, the method has the advantages of high speed, high efficiency, low pollution and low cost, and is a new 'green' technology which is developed rapidly. UV light curable products are composed of three parts of materials, namely photoinitiators, light curable resins and monomers (also known as reactive diluents).

Ultraviolet light emitting diodes (UV-LEDs) are semiconductor electronic devices that convert electrical energy into optical radiation, and UV-LEDs have been widely used as radiation devices in the fields of radiation curing reactions and the like. Compared with the traditional UV light source, the UV-LED light source has the following characteristics: (1) almost can emit monochromatic light, and has very narrow spectral line width (5-20 nm); (2) the luminous output is almost 100%; (3) the energy consumption is low; (4) no ozone is generated; (5) no ultraviolet radiation; (6) the generated heat is low; (7) the operation cost is low; (8) the service life is long; (9) the operation is safe and simple; (10) the design is compact, conveniently carries. The UV-LED light source with low energy consumption and high safety performance is used in industry, so that the safety of personnel can be ensured, and the expenditure can be reduced. In view of the characteristics of advancement, economy, environmental friendliness and the like, the UV-LED has a good development prospect and is applied to some potential new fields.

UV-LED photocuring technology is currently limited by the absorption wavelength of the photoinitiator and the problem of oxygen inhibition during curing. Most of the reported or commercialized photoinitiators have poor absorption of light energy at wavelengths above 365nm, and have poor initiation properties under irradiation with a UV-LED light source. In addition, these commercial photoinitiators are sensitive to oxygen, and must be strictly removed of oxygen during use, which severely limits the development and popularization of UV-LED photocuring technology.

Disclosure of Invention

The invention provides a thioether type naphthalimide derivative photoinitiator containing a hydrogen donor and suitable for UV-LED aerobic light curing and a preparation method thereof. The photoinitiator can well initiate the photopolymerization of monomers to generate a polymer film in the presence of oxygen and has low mobility. Through extensive and intensive research, a series of hydrogen donor-containing thioether type naphthalimide derivative photoinitiators suitable for UV-LED aerobic light curing are prepared through molecular design.

In order to achieve the purpose, the invention adopts the following technical scheme:

1. a thioether-type naphthalimide derivative photoinitiator containing a hydrogen donor and suitable for UV-LED aerobic light curing is characterized in that: the chemical structural general formula of the photoinitiator is shown as follows:

wherein the value range of n is 1-10; r₁Is selected from C₃-C₂₀Aliphatic alkyl groups, hydroxyl groups, vinyl groups, propenyl groups, methyl groups, ethyl groups, alkoxy groups, halogen atoms, aralkyl groups, or phenyl groups; r₂Selected from carboxyl, benzoyl, acetyl, acryloyl, methoxy, ethoxy, nitro.

2. The method of item 1, wherein: the value range of n is 1-5; r₁Selected from vinyl, methyl; r₂Selected from methoxy.

3. The method of item 2, wherein: the value of n is 1.

4. A method for preparing the photoinitiator containing hydrogen donor thioether type naphthalimide derivative and suitable for UV-LED aerobic light curing in the item 1, which is characterized in that: the general synthesis process is as follows:

5. the method of item 4, wherein: the preparation method of the hydrogen donor-containing thioether type naphthalimide derivative photoinitiator suitable for UV-LED aerobic light curing comprises the following steps:

(1) in the step a, adding primary amine and 4-bromo-1, 8-naphthalic anhydride into a reaction vessel, and reacting for 24 hours at 60-100 ℃; after the reaction is finished, cooling, and then washing the crude product with absolute ethyl alcohol for multiple times to obtain a brownish red solid intermediate product A;

(2) in the step a, adding the intermediate product A and acyl chloride into a reaction vessel, adding an anhydrous organic solvent, and reacting for 6 hours at 0-5 ℃; after the reaction is finished, carrying out reduced pressure distillation to remove the anhydrous solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a light yellow solid intermediate product B;

(3) in the step c, adding benzylmercaptan, acetic anhydride and a catalyst into a reactor, heating and refluxing for 12 hours, and stirring; after the reaction is finished, cooling, extracting by dichloromethane, combining organic layers, washing the organic layers by using a carbonate aqueous solution with a certain concentration respectively, then washing by using deionized water, drying the organic layers by using a drying agent, filtering, distilling under reduced pressure to remove a solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a colorless liquid intermediate product C;

(4) in the step d, mixing the intermediate product B prepared in the step B, the intermediate product C prepared in the step C, a palladium catalyst, an iron complex and alkali, adding a proper amount of an organic solvent 1 and an organic solvent 2, and reacting for 24 hours at 80-120 ℃ in a nitrogen atmosphere; and after the reaction is finished, cooling, pouring the reaction solution into a proper amount of saturated salt solution for washing, then extracting with dichloromethane, combining organic phases, washing an organic layer with saturated saline, drying the organic layer with a drying agent, filtering, distilling under reduced pressure to remove the solvent to obtain a crude product, and then purifying the crude product by using a chromatographic column to obtain a final product.

6. The method of item 5, wherein: in the step a, the mole number of the primary amine is 1-10 times of that of 4-bromo-1, 8-naphthalic anhydride; the reaction temperature is 70-90 ℃.

7. The method of item 6, wherein: in the step a, the mole number of the primary amine is 3-6 times of that of 4-bromo-1, 8-naphthalic anhydride.

8. The method of item 7, wherein: in the step a, the mole number of the primary amine is 5 times that of the 4-bromo-1, 8-naphthalic anhydride; the reaction temperature was 85 ℃.

9. The method of item 5, wherein: in the step b, the acyl chloride is selected from one or more of acetyl chloride, acryloyl chloride, methacryloyl chloride, benzoyl chloride, terephthaloyl chloride, oxalyl chloride and p-toluenesulfonyl chloride; the mole number of the acyl chloride is 1-6 times of that of the intermediate product A; the organic base is selected from one or more of triethylamine, diethylamine, 4-dimethylamino pyridine, 3-methylpyridine and 2-methylpyridine; the mole number of the organic base is 1-7 times of that of the intermediate product A; the anhydrous organic solvent is selected from one or more of anhydrous dichloromethane, anhydrous ethanol, anhydrous petroleum ether, anhydrous acetone, anhydrous toluene and anhydrous tetrahydrofuran; the reaction temperature is 0-2 ℃.

10. The method of item 9, wherein: in the step b, the acyl chloride is selected from acetyl chloride and acryloyl chloride; the mole number of the acyl chloride is 2-4 times of that of the intermediate product A; the organic base is selected from triethylamine; the mole number of the organic base is 2-5 times of that of the intermediate product A; the anhydrous organic solvent is selected from anhydrous dichloromethane.

11. The method of item 10, wherein: in the step b, the mole number of the acyl chloride is 3 times that of the intermediate product A; the mole number of the organic base is 4 times that of the intermediate product A; the reaction temperature was 0 ℃.

12. The method of item 5, wherein: in the step c, the mole number of the acetic anhydride is 0.5-4.5 times that of the benzylmercaptan; the catalyst is one or more of ferric chloride, ferrous chloride, cupric chloride, cuprous chloride, nickel chloride, aluminum chloride, sodium nitrate, potassium nitrate and magnesium nitrate; the mole number of the catalyst is 0.001-0.020 times of that of benzylmercaptan; the carbonate aqueous solution is one or more of a sodium carbonate aqueous solution, a potassium carbonate aqueous solution, an ammonium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a potassium bicarbonate aqueous solution and an ammonium bicarbonate aqueous solution; the concentration of the carbonate aqueous solution is 1-25%.

13. The method of item 12, wherein: in the step c, the mole number of the acetic anhydride is 1.5-2.5 times that of the benzylmercaptan; the catalyst is nickel chloride; the mole number of the catalyst is 0.008-0.012 times of that of benzyl mercaptan; the carbonate aqueous solution is sodium bicarbonate aqueous solution; the concentration of the carbonate aqueous solution is 9-12%.

14. The method of item 13, wherein: in the step c, the mole number of the acetic anhydride is 2.0 times that of the benzylmercaptan; the mole number of the catalyst is 0.010 times of that of the benzylmercaptan; the concentration of the aqueous carbonate solution was 10%.

15. The method of item 5, wherein: in the step d, the palladium catalyst is one or more selected from bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, bis (triphenylphosphine) palladium acetate, bis (di-tert-butylphenyl phosphine) palladium dichloride and bis (3,5,3',5' -dimethoxy dibenzylideneacetone) palladium; the iron complex is selected from one or more of 1,1' -bis (diphenylphosphino) ferrocene, 1-bis diphenylphosphino ferrocene nickel chloride and (S, S) - (-) -2,2' -bis [ - (N, N-dimethylamino) (phenyl) methyl ] -1,1' -bis (diphenylphosphino) ferrocene; the inorganic base is selected from one or more of sodium hydroxide, calcium hydroxide, aluminum hydroxide, lithium hydroxide, magnesium hydroxide, zinc hydroxide and anhydrous tripotassium phosphate; the mole number of the palladium catalyst is 0.1-0.8 times that of the intermediate product B; the mole number of the iron complex is 0.10-0.20 times that of the intermediate product B; the mole number of the inorganic base is 1.0-5.0 times of that of the intermediate product B; the mole number of the intermediate product C is 1-5 times that of the intermediate product B; the reaction temperature is 90-115 ℃; the organic solvent 1 and the organic solvent 2 are the same or different and are respectively and independently selected from one or more of toluene, dichloromethane, methanol, acetone, petroleum ether, ethyl acetate and ethanol; the volume of the organic solvent 1 is 1-6 times that of the organic solvent 2; the total volume of the organic solvent 1 and the organic solvent 2 is 1-24 mL; the saturated salt solution is selected from one or more of a saturated ammonium chloride solution, a saturated ammonium sulfate solution, a saturated magnesium chloride solution, a saturated sodium sulfate solution, a saturated potassium chloride solution and a saturated potassium nitrate solution.

16. The method of item 15, wherein: in the step d, the palladium catalyst is selected from bis (dibenzylidene acetone) palladium; the iron complex is selected from 1,1' -bis (diphenylphosphino) ferrocene; the inorganic base is selected from anhydrous tripotassium phosphate; the mole number of the palladium catalyst is 0.3-0.7 times that of the intermediate product B; the mole number of the iron complex is 0.12-0.18 times that of the intermediate product B; the mole number of the inorganic base is 2.0-3.0 times of that of the intermediate product B; the mole number of the intermediate product C is 2-3 times that of the intermediate product B; the reaction temperature is 110 ℃; the organic solvent 1 is toluene; the organic solvent 2 is acetone; the volume of the organic solvent 1 is 2-4 times that of the organic solvent 2; the total volume of the organic solvent 1 and the organic solvent 2 is 5-17 mL; the saturated salt solution is a saturated ammonium chloride solution.

17. The method of item 16, wherein: in the step d, the mole number of the palladium catalyst is 0.6 times that of the intermediate product B; the mole number of the iron complex is 0.14 times that of the intermediate product B; the mole number of the inorganic base is 2.4 times that of the intermediate product B; the mole number of the intermediate product C is 3 times that of the intermediate product B; the volume of the organic solvent 1 is 2 times of that of the organic solvent 2; the total volume of the organic solvent 1 and the organic solvent 2 is 12 mL.

18. The method of item 5, wherein: in the step c and the step d, the drying agent is one or more selected from anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous magnesium chloride and anhydrous calcium chloride.

19. The method of claim 18, wherein: in the step b and the step c, the drying agent is anhydrous sodium sulfate.

20. A free radical photocurable composition comprising the hydrogen donor thioether-containing naphthalimide derivative photoinitiator suitable for UV-LED aerobic photocuring according to item 1; the composition comprises 0.1 to 5 percent of the photoinitiator containing the hydrogen donor thioether type naphthalimide derivative and 95 to 99.9 percent of light-cured resin or monomer based on the total weight of the composition.

21. The composition of item 20, wherein: the light-cured resin is selected from one or more of epoxy (methyl) acrylic resin, polyurethane (methyl) acrylic resin, polyester (methyl) acrylic resin, polyether (methyl) acrylic resin and acrylated poly (methyl) acrylic resin; the monomer is one or more of monofunctional or polyfunctional (methyl) acrylate.

In the following description of the present invention, numerical values in this application are to be considered modified by the word "about", unless expressly stated otherwise. However, the inventors have reported numerical values in the examples as precisely as possible, although such numerical values inevitably include certain errors.

In the present application, specific or preferred embodiments of the present invention may be combined, unless explicitly excluded. Each element of the embodiments of the present application is a specific preferred choice of the generic technical features corresponding thereto. If a feature of the above description can be combined with another feature of the above description, the elements of the embodiments, that is, the specific preferred options, can also be combined with the other feature of the above description. These combinations should be considered part of the original disclosure of the present application.

The invention also provides the application of the photoinitiator in a photocuring system.

The invention has the beneficial effects that: compared with the traditional photoinitiator, the photoinitiator prepared by the invention has obviously prolonged ultraviolet absorption wavelength, obviously improved anti-oxygen polymerization resistance, higher photocuring efficiency under the action of a UV-LED light source and in the presence of oxygen, and is beneficial to the development of the UV-LED photocuring industry; has lower mobility, and is beneficial to the development of food packaging industry.

Drawings

FIG. 1 is a diagram of the photoinitiation mechanism of the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator provided by the invention;

FIG. 2 is a diagram of the mechanism of the antioxidant inhibition of the photoinitiator containing hydrogen donor thioether type naphthalimide derivative provided by the invention;

FIG. 3 is a diagram showing an ultraviolet absorption spectrum of a hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator prepared in example 1-2 of the present invention;

FIG. 4 is a real-time IR spectrum of a hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator prepared in example 1-2 of the present invention and photoinitiators 2959, 184 and 1173 initiating polymerization of monomers in the presence of oxygen;

FIG. 5 is a graph showing migration stability of a hydrogen donor-containing thioether-type naphthalimide derivative photoinitiator prepared in example 1-2 of the present invention in a polymer film;

Detailed Description

The invention will be described in further detail below with reference to the drawings and examples of the specification.

The hydrogen donor-containing thioether type naphthalimide derivative photoinitiator can be subjected to two-way cleavage under the irradiation of an LED light source with the wavelength of 405nm to generate free radicals with initiating activity. As shown in the attached figure 1, under illumination, the photoinitiator firstly reaches an excited singlet state, and then a few excited-state molecules generate a p-methoxybenzyl radical and an aryl sulfur radical through a cracking mode 1; most excited-state molecules generate p-methoxybenzyl sulfide free radicals and aryl free radicals through a cracking mode 2, so that the monomer 1, 6-hexanediol diacrylate (HDDA) is initiated to polymerize to generate a polymer film. The photoinitiator molecules containing the hydrogen donor thioether type naphthalimide derivative can still effectively initiate the monomer polymerization process in the presence of oxygen, as shown in figure 2, the photoinitiator molecules can generate a hydrogen abstraction reaction in an excited singlet state to generate alkyl radicals, and then the alkyl radicals are combined with the oxygen to generate peroxy radicals with a six-membered ring stable structure, but the peroxy radicals can not initiate the monomer polymerization; then, the peroxy radical generates a new alkyl radical to initiate the polymerization of the monomer through two ways of intramolecular hydrogen extraction (mode 1) and intermolecular hydrogen extraction (mode 2), thereby endowing the photoinitiator containing the hydrogen donor thioether type naphthalimide derivative with the performance of reducing oxygen inhibition.

The experimental materials and reagents used in the following examples are commercially available unless otherwise specified.

[ example 1 ]

The photoinitiator NABS-HD-1 has the following structural formula:

the preparation method comprises the following steps:

(a) adding 4-bromo-1, 8-naphthalic anhydride (7.20g, 0.026mol), diglycolamine (13.67g, 0.13mol) and 100mL of absolute ethanol into a 250mL single-neck flask, heating to 85 ℃ under the protection of nitrogen, refluxing and stirring for 4 h; after the reaction is finished, cooling the reaction liquid to room temperature, filtering to obtain a crude product, washing filter residues for multiple times by using absolute ethyl alcohol, and drying in vacuum to obtain an intermediate product, namely BHBD.

(b) BHBD (5.83g, 16mmol) synthesized in example 1, triethylamine (6.48g, 64 mmol) and 150mL of anhydrous dichloromethane were charged in a 250mL single-neck flask, acetyl chloride (3.77 g, 48mmol) was dissolved in 20mL of anhydrous dichloromethane, and the solution was added dropwise to the single-neck flask in an ice-water bath at 0 ℃ and stirred for 6 hours; after the reaction is finished, the solvent is removed by reduced pressure distillation to obtain a crude product, and then the crude product is purified by a chromatographic column to obtain an intermediate product which is named as BDBIEA.

(c) P-methoxybenzyl mercaptan (3.09g, 0.02mol), acetic anhydride (4.08g, 0.04mol) and anhydrous nickel chloride (259mg, 2mmol) were charged into a 50mL one-neck flask, heated to 75 deg.C, and stirred for 4 h. After the reaction is finished, adding a proper amount of deionized water into a reactor, extracting for 3 times by using dichloromethane, combining organic layers, washing the organic layers for 3 times by using 10% sodium bicarbonate aqueous solution and deionized water respectively, and passing the organic layers through anhydrous Na₂SO₄Drying, filtering, distilling under reduced pressure to remove the solvent to obtain a crude product, and purifying the crude product by using a chromatographic column to obtain an intermediate product MOBET;

(d) BDBIEA (812.46mg, 2mmol), MOBET (1.18g g, 6mmol), bis (dibenzylideneacetone) palladium (690.60mg, 1.2mmol), 1' -bis (diphenylphosphino) ferrocene (98.70mg, 0.024mmol), anhydrous tripotassium phosphate (1.02g, 4.8mmol), 8mL of toluene, and 4mL of acetone synthesized in example 1 were charged in a 50mL three-necked flask, and the temperature was raised to 110 ℃ under nitrogen protection, and stirred for 12 hours. After the reaction is finished, cooling the reaction liquid to room temperature, pouring the reaction liquid into 10mL of saturated ammonium chloride aqueous solution, extracting for 3 times by dichloromethane, combining organic phases, washing an organic layer for 3 times by saturated saline solution, and passing the organic layer through anhydrous Na₂SO₄Drying, filtering, distilling under reduced pressure to remove solvent to obtain crude product, purifying with chromatographic column to obtain final product NABS-HD-1, and performing structure identification by nuclear magnetic resonance spectroscopy.

Light guideThe nuclear magnetic hydrogen spectrum data of the hair agent NABS-HD-1 are as follows:¹H NMR(400MHz,Chloroform- d)δ8.63(dd,J＝7.6,1.2Hz,1H),8.58(dd,J＝8.4,1.2Hz,1H),8.46(d,J＝7.6Hz, 1H),7.76(dd,J＝8.8,7.6Hz,1H),7.60(d,J＝7.6Hz,1H),7.33(d,J＝8.8Hz,2H), 6.88(d,J＝8.8Hz,2H),4.45(t,J＝6.4Hz,2H),4.33(s,2H),4.19(dd,J＝4.8，4.4 Hz,2H),3.85(t,J＝6.0Hz,2H),3.80(s,2H),3.76(dd,J＝4.8，4.8Hz,2H),1.98(s, 3H)。

the nuclear magnetic carbon spectrum data of the photoinitiator NABS-HD-1 are as follows:¹³C NMR(100MHz,Chloroform- d)δ171.1,164.1,159.3,144.9,131.6,130.9,130.3,130.1,129.7,127.1,126.7,124.1, 123.1,119.5,114.3,68.5,67.9,63.7,55.3,38.9,37.1,29.7,20.9。

[ example 2 ]

The photoinitiator NABS-HD-2 has the following structural formula:

the preparation method comprises the following steps:

(a) BHBD (5.83g, 16mmol) synthesized in example 1, triethylamine (6.48g, 64 mmol) and 150mL of anhydrous dichloromethane were charged in a 250mL single-neck flask, acryloyl chloride (4.35g, 48mmol) was dissolved in 20mL of anhydrous dichloromethane, and the solution was added dropwise to the single-neck flask in an ice-water bath at 0 ℃ and stirred for 6 hours; after the reaction is finished, the solvent is removed by reduced pressure distillation to obtain a crude product, and then the crude product is purified by a chromatographic column to obtain an intermediate product which is named as BDBIEB.

(b) BDBIEB (836.90mg, 2mmol), MOBET (1.18g g, 6mmol), bis (dibenzylideneacetone) palladium (690.60mg, 1.2mmol), 1' -bis (diphenylphosphino) ferrocene (98.70mg, 0.024mmol), anhydrous tripotassium phosphate (1.02g, 4.8mmol), 8mL toluene, and 4mL acetone synthesized in example 1 were charged into a 50mL three-necked flask, and the temperature was raised to 110 ℃ under nitrogen protection and stirred for 12 h. After the reaction, after the reaction solution was cooled to room temperature, the reaction solution was poured into 10mL of saturated aqueous ammonium chloride solution, extracted with dichloromethane for 3 times, the organic phases were combined, the organic layer was washed with saturated brine for 3 times,the organic layer was passed over anhydrous Na₂SO₄Drying, filtering, distilling under reduced pressure to remove solvent to obtain crude product, purifying with chromatographic column to obtain final product NABS-HD-2, and performing structure identification by nuclear magnetic resonance spectroscopy.

The nuclear magnetic hydrogen spectrum data of the photoinitiator NABS-HD-2 is as follows:¹H NMR(400MHz,Chloroform- d)δ8.63(dd,J＝7.2，1.2Hz,1H),8.59(dd,J＝7.2，1.2Hz,1H),8.46(d,J＝8.0Hz, 1H),7.76(dd,J＝8.4,7.2Hz,1H),7.61(d,J＝8.0Hz,1H),7.34(d,J＝8.4Hz,2H), 6.89(d,J＝8.4Hz,2H),6.33(dd,J＝17.2，1.6Hz,1H),6.05(d,J＝17.6，10.4Hz, 1H),5.73(d,J＝10.4，1.6Hz,1H),4.46(t,J＝6.0Hz,2H),4.43(s,2H),4.29(dd,J＝ 4.8，4.8Hz,2H),3.87(t,J＝6.0Hz,2H),3.81(s,2H),3.80(dd,J＝4.8，4.4Hz,2H)。

the nuclear magnetic carbon spectrum data of the photoinitiator NABS-HD-2 are as follows:¹³C NMR(100MHz,Chloroform- d)δ166.1,164.0,163.9,159.3,144.9,131.5,130.8,130.7,130.2,130.1,129.5,128.2, 128.1,126.9,126.6,123.8,122.9,119.3,114.2,68.5,67.9,63.7,55.3,38.9,36.9。

[ examples 3 to 8 ]

Examples 3 to 8 are intended to illustrate that the photoinitiator containing hydrogen donor thioether type naphthalimide derivative prepared in examples 1 to 2 can effectively initiate the polymerization of 1, 6-hexanediol diacrylate (HDDA) monomer in the presence of oxygen under the irradiation of a UV-LED light source; the initiation activity is higher than that of the prior photoinitiators 2959, 184 and 1173.

(1) Preparing a photosensitive resin composition: the mixture ratio is as follows:

a: 1, 6-hexanediol diacrylate (99.5 or 98 parts by mass)

B: photoinitiator (0.5 parts by mass)

C: photoinitiator (2.0 parts by mass)

Table 1 shows the composition ratios in the examples:

(2) test for polymerization Properties

The test method comprises the following steps: stirring the above composition in dark, uniformly coating on potassium bromide salt sheet with capillary to form a film of about 30 μm, and placing in a real-time infrared instrument (American Saimer Feishell science & technology, model UVEC-411, light intensity of 100 mW/cm)²) The coating film was exposed to light at a wavelength of 405nm for a period of 900 s.

And (3) testing results: FIG. 3 shows that the hydrogen donor-containing thioether-type naphthalimide derivative photoinitiators prepared in examples 1-2 have good ultraviolet absorption capacity at the emission wavelength of an LED light source; FIG. 4 shows that the photosensitive resin composition containing three commercial photoinitiators can not initiate the polymerization of monomers under the irradiation of a 405nm UV-LED light source and in the presence of oxygen (examples 3-5), while the photosensitive resin composition containing the photoinitiator of thioether type naphthalimide derivative containing a hydrogen donor prepared by the invention can successfully initiate the photopolymerization under the irradiation of a 405nm UV-LED light source and in the presence of oxygen (examples 6-8), which indicates that the photoinitiator of thioether type naphthalimide derivative containing a hydrogen donor prepared by the invention has better applicability in a UV-LED oxygen photocuring system.

[ example 9 ]

This example is intended to illustrate that NABS-HD-2, a photoinitiator of thioether type naphthalimide derivative containing hydrogen donor prepared in example 2, can have a lower mobility in a polymer film.

The test method comprises the following steps: weighing 0.01g of hydrogen donor-containing thioether type naphthalimide derivative photoinitiator prepared in the embodiment 1-2 and 2.00g of 1, 6-hexanediol diacrylate (HDDA) to be mixed to prepare a photosensitive solution; preparing a template by using a silica gel film with the thickness of 1-2mm, and padding a glass sheet with the thickness of 2mm on the bottom of the template; introducing the photosensitive solution into the template, uniformly coating without bubbles, and covering a cover glass; irradiating the photosensitive solution by using an LED light source with the wavelength of 405nm until the photosensitive solution is solidified; grinding the cured resin into powder, taking 1g of the ground resin powder, and soaking the powder in 20mL of anhydrous acetone for 3 days; the sample was filtered to remove solids to obtain a liquid, and a liquid chromatogram was obtained using a liquid chromatograph-mass spectrometer (Waters, USA), as shown in FIG. 5.

And (3) testing results: FIG. 5 shows that, in the liquid chromatogram after extraction of the polymer film containing NABS-HD-1, the peak a appearing at 5.71min is assigned to HDDA molecules, and the peak b appearing at 6.40min is assigned to NABS-HD-1 molecules contained in the polymer, and the peaks are very distinct, which indicates that the NABS-HD-1 molecules are free in the polymer and easily migrate out of the polymer. In contrast, in the liquid chromatogram after the extraction of the polymer film of NABS-HD-2, only the peak of HDDA appears in the figure, and the chromatographic peak of NABS-HD-2 is not found. This indicates that the probability of NABS-HD-2 migrating out of the polymer matrix is much lower than that of NABS-HD-1, because the carbon-carbon double bond existing in the molecule of NABS-HD-2 can also participate in polymerization reaction and be anchored on the polymer skeleton, making it difficult to migrate. The photoinitiator NABS-HD-2 has excellent migration stability.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and various process schemes having no substantial difference from the concept of the present invention are within the protection scope of the present invention.