A kind of bipyridine compound, photoinitiator and its preparation method and application

Abstract

The present application relates to the technical field of photocuring, in particular to a kind of biscalbazoles compound, photoinitiator and its preparation method and application, the structural formula of the biscalbazoles compound is selected from any one in the following structural formula: Wherein, R1 It is selected from any one of substituted or unsubstituted alkyl of carbon atom number 1~20, substituted or unsubstituted cycloalkyl of carbon atom number 3~20, substituted or unsubstituted halogenated alkyl of carbon atom number 1~20, m It is selected from the integer of 0~5, R2 It is selected from any one of substituted or unsubstituted alkyl of carbon atom number 1~20, substituted or unsubstituted cycloalkyl of carbon atom number 3~20, substituted or unsubstituted aryl of carbon atom number 6~20, substituted or unsubstituted heteroaryl of carbon atom number 3~20, the present application is applied to curing film.

Description

Technical Field

[0001] This invention relates to the field of photocuring technology, and in particular to a bicarbazole compound, a photoinitiator, its preparation method, and its application. Background Technology

[0002] Colored photoresist is a crucial material in color filters, primarily composed of red, green, and blue polymers. In recent years, with increasing demand for televisions and continuous expansion of panel manufacturing, the demand for colored photoresist has steadily grown. Traditional methods for producing colored photoresist include dyeing and electroprecipitation, both of which require the use of metallic chromium (Cr). However, Cr is highly toxic and causes significant pollution. Therefore, the more advanced pigment dispersion method is currently employed, offering a simpler process and excellent color properties, heat resistance, and lightfastness. Pigment photoresist production is a key technology in the pigment dispersion method, and photoinitiators are essential raw materials. However, traditional photoinitiators such as benzoin derivatives, biphenyl ketals, phosphine oxides, and benzophenone / amines suffer from low photosensitivity, poor solubility, and poor storage stability, directly affecting the transparency and heat resistance of colored photoresist and failing to meet the requirements for high-quality pigment photoresist production.

[0003] In 1904, A. Werner first reported the photochemical properties of oxime esters, and in 1970, oxime esters began to be used as photoinitiators. The oxime ester photoinitiator Quanta cure PDO was widely commercialized. Although this compound exhibited high photoinitiating activity, its poor stability led to its rapid replacement by other free radical initiators. In recent years, researchers have introduced groups that increase the conjugated surface area of ​​oxime ester molecules, further improving the initiation efficiency and stability of oxime ester derivatives, thus attracting attention to the preparation and application of oxime ester photoinitiators. Typical examples include the research by Hisatoshi Kura et al. on introducing diphenyl sulfide groups into oxime ester compounds and the research by Dietliker K et al. on introducing carbazole groups into oxime ester compounds. Due to the large conjugated system and strong intramolecular electron transfer characteristics of these groups, the stability and photosensitivity of these oxime ester compounds are greatly improved.

[0004] Existing carbazole oxime photoinitiators meet the requirements of LCD flat panel displays to a certain extent. Furthermore, introducing electron-withdrawing groups such as nitro groups into the carbazole oxime structure causes a redshift in the UV absorption spectrum due to the interaction between DA groups. Adding -NO2 to the carbazole ring can also redshift the absorption spectrum, resulting in relatively large absorption in the 365-405 nm range. Currently, UV curing exposure machines are gradually changing from mercury lamps to UV-LED lamps. With the continuous improvement of LDI exposure machines and increased production efficiency, many fields are using laser direct-drawing processes and equipment for direct computer-aided design and printing, eliminating the need for photomasks. Since the exposure wavelength of LDI equipment is 405 nm, the strong absorption of the initiator at around 405 nm is crucial for selecting an initiator for UV-curable coatings used in LDI. However, this modification has the disadvantage of reduced solubility, affecting the application range and effectiveness. Simultaneously, the nitration reaction is a strongly exothermic reaction with a fast reaction rate; improper control can lead to explosions. To maintain a certain nitration temperature, the nitration reactor usually requires a good heat transfer device. Therefore, the introduction of nitro groups places higher demands on the overall equipment.

[0005] In recent years, research on initiators has been very active, and higher requirements have been put forward for the performance of high-sensitivity photoinitiators. Summary of the Invention

[0006] The embodiments of the present invention provide a bicarbazole compound, a photoinitiator, a preparation method thereof, and its application to solve the above-mentioned problems.

[0007] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0008] This invention provides a bicarbazole compound, wherein the structural formula of the bicarbazole compound is selected from any of the following structural formulas:

[0009] , ,

[0010] Formula (I) Formula (II) Formula (III)

[0011] Wherein, R1 is selected from any one of substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, or substituted or unsubstituted alkyl halogen groups having 1 to 20 carbon atoms; m is selected from an integer from 0 to 5; and R2 is selected from any one of substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 20 carbon atoms, or substituted or unsubstituted heteroaryl groups having 3 to 20 carbon atoms.

[0012] Optionally, R1 is selected from any one of methyl, ethyl, propyl, tert-butyl, nonafluorotert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl, and R2 is selected from any one of methyl, ethyl, propyl, butyl, phenyl, cyclopropyl, isononyl, cyclobutyl, cyclopentyl, or cyclohexyl.

[0013] The present invention also provides a photoinitiator prepared from the above-mentioned bicarbazole compound, the structural formula of which is shown below:

[0014]

[0015] Wherein, R3 is selected from any one of the following: alkyl group with 1 to 20 carbon atoms (substituted or unsubstituted), alkenyl group with 2 to 12 carbon atoms (substituted or unsubstituted), cycloalkyl group with 3 to 20 carbon atoms (substituted or unsubstituted), aryl group with 6 to 20 carbon atoms (substituted or unsubstituted), and heteroaryl group with 3 to 20 carbon atoms (substituted or unsubstituted), and m is selected from an integer from 0 to 5.

[0016] Optionally, R3 is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, tetrahydrofuranyl, tetrahydrothiophenyl, tetrahydropyranyl, tetrahydrothiophenyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl; m is selected from 1 or 2.

[0017] Optionally, R3 is selected from methyl, ethyl, cyclopentyl, or cyclohexyl.

[0018] Optionally, the photoinitiator is selected from one of the following structural formulas:

[0019]

[0020] .

[0021] The present invention also provides a method for preparing a photoinitiator as described above, comprising the following reaction steps:

[0022] A. Compound I is reacted with bicarbazole, aluminum trichloride, and compound I in an organic solvent to obtain compound II. The reaction equation is shown below:

[0023] ;

[0024] B. Compound II obtained in step A is added to an organic solvent along with compound III and aluminum trichloride to react and yield compound IV. The reaction equation is shown below:

[0025] ;

[0026] C. Compound IV obtained in step B is added to an organic solvent along with hydroxylamine hydrochloride and sodium acetate to react and give compound V. The reaction equation is shown below:

[0027] ;

[0028] D. Compound V obtained in step C is reacted with compound VI in an organic solvent to obtain compound VII. The reaction equation is shown below:

[0029] .

[0030] R1, R2 and R3 are selected from the substituents described above.

[0031] Optionally, in step A, the equivalence ratio of bicarbazole, aluminum trichloride, and compound I is 1:(1.9-2.5):(1.9-2.5); in step B, the equivalence ratio of compound II, aluminum trichloride, and compound III is 1:(1.9-3.5):(1.9-3.5); in step C, the equivalence ratio of compound IV, hydroxylamine hydrochloride, and sodium acetate is 1:(1.9-5):(3-5); and in step D, the equivalence ratio of compound V obtained in step C to compound VI is (1-2):(2-6).

[0032] The present invention also provides a photosensitive resin comprising the above-mentioned photoinitiator and an acrylic resin prepolymer, wherein the mass ratio of the photoinitiator to the acrylic resin prepolymer is 1:(20-25).

[0033] The present invention also provides a cured film comprising the above-mentioned photosensitive resin.

[0034] Compared with the prior art, the beneficial effects of this application are as follows:

[0035] This application provides compounds with a bicarbazole group for preparing oxime ester photoinitiators containing a bicarbazole group.

[0036] The oxime ester photoinitiator containing the bicarbazole group provided in this application introduces the bicarbazole group by linking the two carbazoles at the 9 position through a single bond, forming a bicarbazole structure. Compared with the absorption spectrum of OXE02 carbazole oxime esters, it exhibits a red shift, and compared with nitro-substituted carbazole oxime ester photoinitiators, it has superior solubility.

[0037] The method for preparing oxime ester photoinitiators containing bicarbazole groups provided in this application involves a simple four-step reaction to obtain the target product. The photocurable coatings and cured films provided in this application can be rapidly cured with a small amount of photoinitiator and low photosensitivity energy, and the cured films are less prone to yellowing. Detailed Implementation

[0038] The technical solutions in some embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments provided in this disclosure, all other embodiments obtained by those skilled in the art are within the scope of protection of this disclosure.

[0039] Preparation Examples of Photoinitiators

[0040] Example 1 is the synthesis of compound 1-1

[0041] The synthetic route for compound 1-1-A is shown below:

[0042]

[0043] Under nitrogen protection, 400 mL of dichloroethane, 67.5 g of aluminum trichloride, and 84.6 g of bicarbazole were added to a 1000 mL reaction flask. The mixture was cooled to a material temperature of 0–3 °C, and then 80.6 g of o-methylbenzoyl chloride (compound A) and 60 g of dichloroethane solution were slowly added dropwise. After the addition was complete, the reaction was stopped after 1 hour and the flask was sealed for later use.

[0044] The synthetic route for compound 1-1-B is shown below:

[0045]

[0046] Under nitrogen protection, 400 mL of dichloroethane and 103 g of aluminum trichloride were added to a 1000 mL reaction flask. The temperature was lowered to 5-10 °C and 64 g of acetyl chloride (compound B) was added dropwise. After the addition was complete, the mixture was stirred at 5-10 °C until it was completely dissolved. The solution was then transferred to a constant pressure dropping funnel and added dropwise to the reaction system of compound 1-1-A. After the reaction was complete, dilute hydrochloric acid was added to quench the reaction. The mixture was then washed once with water, separated, and the organic phase was concentrated. After crystallization in a toluene / ethanol system, 118 g of yellow solid of compound 1-1-B was obtained, with a yield of 70%.

[0047] The synthetic route for compound 1-1-C is shown below:

[0048]

[0049] 100 g of the yellow solid 1-1-B and 400 g of dichloroethane were added to a reaction flask, followed by 27.9 g of hydroxylamine hydrochloride and 45.3 g of sodium acetate. The mixture was heated to reflux for 3 h. After the reaction was complete, the mixture was cooled and filtered to remove inorganic salts. The filter cake was washed with a small amount of dichloroethane, and the organic phase was concentrated and then slurried with ethanol to obtain 94 g of solid 1-1-C, with a yield of 89.8%.

[0050] The synthetic route for compound 1-1 is shown below:

[0051]

[0052] 94 g of compound 1-1-C and 400 mL of dichloroethane were added to the reaction flask. The mixture was then cooled to 0-5 °C, and 27 g of acetyl chloride (compound C) was added dropwise. After the reaction was complete, the mixture was neutralized with alkali solution, washed with water until neutral, separated, concentrated the organic phase, and then slurried with ethanol to obtain 94.5 g of white solid of compound 1-1, with a yield of 89.5%.

[0053] Examples 2-8

[0054] Referring to the synthetic route of compound 1-1 in Example 1, and selecting corresponding compounds A, B and C, a series of specific compounds of the present invention were prepared (see Table 1).

[0055] Table 1

[0056]

[0057] Preparation Examples of Photosensitive Resins

[0058] Example 9

[0059] 96g of acrylic resin prepolymer, 4g of compound 1-1 (prepared in Example 1) and 100g of tetrahydrofuran were added to a reaction vessel at 35°C and reacted for 6 hours. After stirring until homogeneous, polymeric composition No.1 was obtained.

[0060] Examples 10-16

[0061] Except that compounds 1-1 obtained in Example 1 were replaced with the compounds shown in Table 2 below, polymerizable compositions No. 2 to No. 8 were obtained by the same method as in Example 9.

[0062] Example 17

[0063] 98g of acrylic resin prepolymer, 2g of compound 1-1 obtained in Example 1 and 100g of tetrahydrofuran were added to a reaction vessel at 35°C and reacted for 6 hours. After stirring until homogeneous, polymeric composition No. 9 was obtained.

[0064] Examples 18-24

[0065] Except that compounds 1-1 obtained in Example 1 were replaced with the compounds shown in Table 2 below, polymerizable compositions No. 10 to No. 16 were obtained by the same method as in Example 8.

[0066] Comparative Examples 1-2

[0067] Except that compounds 1-1 obtained in Example 1 were replaced with the compounds shown in Table 2 below, polymerizable compositions No. 17 to No. 18 were obtained by the same method as in Example 1.

[0068] Comparative Examples 3-4

[0069] Except that compounds 1-1 obtained in Example 1 were replaced with the compounds shown in Table 2 below, polymerizable compositions No. 19 to No. 20 were obtained by the same method as in Example 8.

[0070] Table 2

[0071] Example 9 96 g Compound 1-1 100 g Example 10 96 g Compounds 1-3 100 g Example 11 96 g Compounds 1-5 100 g Example 12 96 g Compounds 1-8 100 g Example 13 96 g Compounds 1-10 100 g Example 14 96 g Compounds 1-13 100 g Example 15 96 g Compounds 1-20 100 g Example 16 96 g Compounds 1-21 100 g Example 17 98 g Compound 1-1 100 g Example 18 98 g Compounds 1-3 100 g Example 19 98 g Compounds 1-5 100 g Example 20 98 g Compounds 1-8 100 g Example 21 98 g Compounds 1-10 100 g Example 22 98 g Compounds 1-13 100 g Example 23 98 g Compounds 1-20 100 g Example 24 98 g Compounds 1-21 100 g Comparative Example 1 96 g OXE02 100 g Comparative Example 2 96 g 358 100 g Comparative Example 3 98 g OXE02 100 g Comparative Example 4 98 g 358 100 g

[0072] The structures of the compounds involved in the comparative examples of polymerizable compositions are as follows:

[0073]

[0074] The photosensitivity of the polymeric compositions of Examples 9-24 and Comparative Examples 1-4 was evaluated according to the following methods.

[0075] 1. Evaluation of photosensitivity under blue and green light sources

[0076] The polymeric compositions of Examples 9-16 and Comparative Examples 1-2 were coated onto glass substrates using a spin coater. Using a spin coater, the substrates were heated to 100°C at 1500 rpm and held for 2 minutes, then cooled to room temperature to form a coating film on the surface of the glass substrates. The polymeric compositions of Examples 9-16 and Comparative Examples 1-2 were then cured under blue and green light sources, respectively. Table 3 shows the exposure amount of the required light energy; a lower value indicates better photosensitivity. The results are shown in Table 3.

[0077] Table 3

[0078] Example 9 1-1 35 30 Example 10 1-3 40 37 Example 11 1-5 30 26 Example 12 1-8 32 30 Example 13 1-10 45 38 Example 14 1-13 36 30 Example 15 1-20 38 32 Example 16 1-21 42 35 Comparative Example 1 OXE02 80 60 Comparative Example 2 358 75 56

[0079] 2. Evaluation of photosensitivity under red light source irradiation

[0080] The polymeric compositions of Examples 17-24 and Comparative Examples 3-4 were coated onto glass substrates using a spin coater. Using a spin coater, the substrates were heated to 100°C at 1500 rpm and held for 2 minutes, then cooled to room temperature to form a coating film on the surface of the glass substrates. The polymeric compositions of Examples 17-24 and Comparative Examples 3-4 were then cured under red light irradiation. The data in Table 4 represent the required light energy exposure; a lower value indicates better photosensitivity. The results are shown in Table 4.

[0081] Table 4

[0082] Example 17 Compound 1-1 23 Example 18 Compounds 1-3 25 Example 19 Compounds 1-5 24 Example 20 Compounds 1-8 23 Example 21 Compounds 1-10 28 Example 22 Compounds 1-13 24 Example 23 Compounds 1-20 25 Example 24 Compounds 1-21 29 Comparative Example 3 OXE02 35 Comparative Example 4 358 32

[0083] As shown in Tables 3 and 4, under blue, green, and red light sources, the energy required for curing the polymerizable composition containing the oxime ester compound of the present invention is significantly less than the energy required for curing the compound (OXE02, 358) used in the comparative examples. Compared with the compound (OXE02, 358) used in comparative examples 1 to 4, the oxime ester compound of the present invention has excellent photosensitivity.

[0084] As described above, the oxime ester compounds of the present invention exhibit excellent photosensitivity, and are useful as photoinitiators for optical applications.

[0085] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A bicarbazole compound, characterized in that, The structural formula of the bicarbazole compound is selected from any one of the following structural formulas: 、 、 Formula (I) Formula (II) Formula (III) Wherein, R1 is selected from any one of methyl, ethyl, propyl, tert-butyl, nonafluorotert-butyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl, R2 is selected from any one of methyl, ethyl, propyl, butyl, phenyl, cyclopropyl, isononyl, cyclobutyl, cyclopentyl or cyclohexyl, and m is selected from an integer from 0 to 5.

2. A photoinitiator, characterized in that, The photoinitiator, prepared from a bicarbazole compound according to claim 1, has the following structural formula: Wherein, R3 is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, tetrahydrofuranyl, tetrahydrothiophenyl, tetrahydropyranyl, tetrahydrothiophenyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl; m is selected from 1 or 2, and R1 and R2 are selected from the substituents as described in claim 1.

3. A photoinitiator according to claim 2, characterized in that, R3 is selected from methyl, ethyl, cyclopentyl, or cyclohexyl.

4. A photoinitiator according to claim 2, characterized in that, The photoinitiator is selected from one of the following structural formulas: 。 5. A method for preparing a photoinitiator as described in any one of claims 2-4, characterized in that, The reaction steps include the following: A. Compound I is reacted with bicarbazole, aluminum trichloride, and compound I in an organic solvent to obtain compound II. The reaction equation is shown below: ; B. Compound II obtained in step A is added to an organic solvent along with compound III and aluminum trichloride to react and yield compound IV. The reaction equation is shown below: ; C. Compound IV obtained in step B is added to an organic solvent along with hydroxylamine hydrochloride and sodium acetate to react and give compound V. The reaction equation is shown below: ； D. Compound V obtained in step C is reacted with compound VI in an organic solvent to obtain compound VII. The reaction equation is shown below: R1, R2 and R3 are selected from the substituents as described in claim 1 or 2.

6. The preparation method according to claim 5, characterized in that, In step A, the equivalent ratio of bicarbazole, aluminum trichloride, and compound I is 1:(1.9-2.5):(1.9-2.5). In step B, the equivalent ratio of compound II, aluminum trichloride, and compound III is 1:(1.9-3.5):(1.9-3.5). In step C, the equivalent ratio of compound IV, hydroxylamine hydrochloride, and sodium acetate is 1:(1.9-5):(3-5). In step D, the equivalent ratio of compound V to compound VI obtained in step C is (1-2):(2-6).

7. A photosensitive resin, characterized in that, The composition comprises a photoinitiator according to any one of claims 2-4 and an acrylic resin prepolymer, wherein the mass ratio of the photoinitiator to the acrylic resin prepolymer is 1:(20-25).

8. A cured film, characterized in that, Includes the photosensitive resin described in claim 7.

Images