JP5647738B2 - High-sensitivity carbazole oxime ester photoinitiator, process for its production and use - Google Patents

Description

  The present invention relates to the technical field of photoinitiators, and more particularly to a carbazole oxime ester photoinitiator, a method for producing the same, and use thereof.

  Photocuring refers to the curing process under light induction of a monomer, oligomer or polymer substrate. The technology is widely used in modern microelectronic technology. For example, photocurable ink, liquid crystal panel sealing, photosensitive printing plate, filter, and photoresist. At the heart of photocuring technology is a photocurable polymerized monomer and a suitable photoinitiator. Under the irradiation of ultraviolet / visible light, X-rays or laser with a certain wavelength, the photoinitiator produces active groups, excites unsaturated groups in the polymerizable monomer to initiate the polymerization reaction, and cures the material cause.

  The photoinitiator is the most important factor affecting the photosensitivity of the photocuring composition (photosensitive composition). Currently, there are many reports on photoinitiators, such as benzoic derivatives, benzyl ketals, α, α-dialkoxyacetophenones, benzophenones / amines, Michler ketones, thiazolones / amines, aromatic diazonium salts, triazoxides, There are oxime ester type, and typical examples are commercially available Irgacure369, Darocure1173, OXE-1 and OXE-2. However, these photoinitiators are low in photosensitivity (high polymerization rate and high amount of exposure agent) in practical application, poor in solubility (high in transparency and lithography residue), and low in storage stability. There are some shortcomings such as lack of sensitivity at short wavelengths, which affect the properties of the photosensitive material as a whole, so the application needs of high quality color filters and new generation LED displays cannot be satisfied. In addition, the use of a photoinitiator with low photosensitivity demands an unspecified requirement for equipment layout in actual production, which adversely affects the product production rate.

  On the current staircase, research on photoinitiators with high photosensitivity attracted attention, and a small amount of news was also seen. For example, publication number CN101508744A discloses a carbazole oxime ester photoinitiator, which has excellent photosensitivity due to OXE-2 and can satisfy the production needs of color filters for the time being. With the development, higher needs for photoinitiators will be required, and existing photoinitiators will gradually become unsatisfied with the application needs of high quality color filters and LEDs. The research and development of photoinitiators with higher properties, in particular higher photosensitivity, have important real and economic implications.

CN101508744A

  It is an object of the present invention to provide a novel photoinitiator that has excellent application characteristics, particularly very high photosensitivity, and can satisfy the production needs of high quality color filters and OLED displays.

In order to achieve the above technical effect, the technical solution of the present invention relates to a carbazole oxime ester photoinitiator having a structure represented by the formula (1).

[However,
R ₁ is

And
R ₂ is a C _{1 to} C ₂₀ linear or branched alkyl group,
Ar is an S- or O-containing heterocyclic group having an optional substituent (that is, which may have a substituent), or a substituted aryl group containing an O, S, or N atom in the substituent. ]

In the carbazole oxime ester compound represented by the formula (1), the R ₁ substituent is preferably n = 2, m = 3 or 4.

R ₂ is preferably a C _{1 to} C ₅ linear or branched alkyl group, more preferably methyl, ethyl, n-propyl, or n-butyl, and particularly preferably ethyl.

  In Ar, the S- or O-containing heterocyclic group having an optional substituent preferably has 0 to 2 substituents, more preferably 0 to 2 methyl or ethyl. The S or O-containing heterocyclic group is preferably a furyl group or a thienyl group. The substituent containing O, S, N atoms in the substituted aryl group is preferably an alkylthio group, an alkoxy group, an alkylamino group, a piperazinyl group, or a morpholinyl group.

Specifically, in the carbazole oxime ester compound represented by the formula (1), the Ar group is preferably selected from the following structures.

  The present invention also provides a method for producing a carbazole oxime ester photoinitiator having a structure represented by the above formula (1). The method uses carbazole as a raw material and includes the following steps.

(1) Substitution reaction: Dissolve carbazole in an organic solvent and perform a substitution reaction with brominated hydrocarbon R ₂ -Br to obtain intermediate a (ie, 9-R ₂ group carbazole). The reaction process is as follows.

(2) Acylation reaction: Intermediate a (9-R _2- group carbazole) is dissolved in an organic solvent and subjected to an acylation reaction under the action of aluminum chloride to produce intermediate b (ie, 3-R ₁ Acyl-6-Ar acyl-9-R ₂ group carbazole) is obtained. The reaction process is as follows.

(3) Oximation reaction: The obtained intermediate b (3-R ₁ acyl-6-Ar acyl-9-R ₂ carbazole) is subjected to an oximation reaction to give intermediate c (ie, 1- (6- Ar acyl-9-R ₂ carbazoyl) -1-R ₁ ketone oxime) is obtained. The reaction process is as follows.

(4) Esterification reaction: The target product is obtained by esterification of the obtained intermediate c (1- (6-Ar acyl-9-R _2- group carbazoyl) -1-R ₁ ketone oxime) with acetic anhydride. That is, a carbazole oxime ester photoinitiator represented by the formula (I) is obtained. The reaction process is as follows.

  All the raw materials used in the production method of the present invention are compounds known in the prior art, and are obtained from commercial sources or produced by known synthesis methods.

  The carbazole oxime ester compound having the structure represented by the formula (1) can be used as a photoinitiator in a photosensitive (photocuring) composition and has very excellent photosensitivity. Here, the other components in the photosensitive composition are not particularly limited, and known and commonly used components in the art (for example, refer to the contents disclosed in CN101059655A, which is referred to by reference), for example, photopolymerizable There may be an acrylic resin.

  The beneficial technical effects of the present invention are as follows. That is, in the present invention, the carbazole oxime ester photoinitiator represented by the formula (1) has excellent application characteristics, has particularly high photosensitive characteristics, and is commercially available at the present stage, such as Irgacure369 and OXE-2. This photoinitiator is superior to the carbazole oxime ester photoinitiator disclosed in CN101508744A. When applied to a photosensitive composition, the photocuring characteristics can be greatly improved, and the application field of the photosensitive composition, for example, the production rate of color filter production is significantly improved. At the same time, the production method of the present invention is simple, does not produce contaminated waste in the production process, has high product purity, and can be applied to industrial production.

Manufacturing Example Example 1:
Production of 1- [6- (2-thienylformyl) -9-ethylcarbazol-3-yl]-(3-cyclopentylacetone) -1-oxime acetate represented by the following formula

Step 1: Preparation of 9-ethylcarbazole

Add 20 g of carbazole, 0.8 g of tetraethylammonium bromide, and 100 mL of toluene to a 250 mL four-necked flask, and add 70 g of 50% NaOH aqueous solution with stirring, and stir 15.6 g of bromoethane over about 30 minutes. After dropping, the mixture was heated and refluxed for 6 hours. After cooling to room temperature, the aqueous layer was separated, and the product liquid layer was washed with water three times, dried over anhydrous MgSO ₄ , and then suction filtered. The solvent was removed by concentration under reduced pressure, and the residue was recrystallized with anhydrous alcohol to obtain 33.5 g of white needle crystals. The yield was 72.0% and the relative purity was 99.0%.

Step 2: Preparation of 3- (3-cyclopentylpropanoyl) -6- (2-thienylformyl) -9-ethylcarbazole

A 500 ml four-necked flask was charged with 30 g of 9-ethylcarbazole, 21.6 g of AlCl ₃ (finely pulverized) and 150 ml of dichloromethane, and while stirring, argon gas was introduced for protection and cooled in an ice bath. When the temperature dropped to 0 ° C., dropwise addition of a mixture of 23.2 g of 2-thienyl formic acid chloride and 21 g of dichloromethane was started, and the temperature was controlled to 10 ° C. or lower. The dropwise addition was completed in about 1.5 hours, followed by stirring for 2 hours. After that, 21.6 g AlCl ₃ (finely pulverized) was added to the flask, and then a mixture of 27.2 g cyclopentylpropionic acid chloride and 20 g dichloromethane was added dropwise in about 1.5 hours while controlling the temperature to 10 ° C. or lower. Completed. Thereafter, the temperature was raised to 15 ° C., followed by stirring for 2 hours, and the product was taken out.

Post-processing:
Under stirring, the product was slowly poured into dilute hydrochloric acid containing 400 g of ice and 65 ml of concentrated hydrochloric acid, the lower layer product liquid was taken out with a separatory funnel, and the upper layer was extracted with 50 ml of dichloromethane. The extract and the product liquid were combined, washed with a NaHCO ₃ solution containing 10 g of NaHCO ₃ and 200 g of water, and further washed three times with 200 ml of water until the pH value became neutral. After drying over 30 g anhydrous MgSO ₄ to remove water, the dichloromethane was rotoevaporated. After evaporation, the crude product in the rotary evaporation bottle was in the form of a solid powder, put into petroleum ether distilled at 200 ml of atmospheric pressure, and suction filtered to obtain a pale yellow powdery solid. Drying in an oven at 70 ° C. for 2 hours yielded 46.2 g of product. The yield was 70% and the purity exceeded 94%.

Step 3: Preparation of 1- [6- (2-thienylformyl) -9-ethylcarbazol-3-yl]-(3-cyclopentylacetone) -1-oxime

Into a 500 ml four-necked flask is charged 46.2 g of the product of the second step, 11.2 g of hydroxylamine hydrochloride, 16.4 g of sodium acetate, 150 g of alcohol, 50 g of water, and refluxed for 5 hours while heating and stirring. Reacted.
Post-processing:
The product was poured into a large beaker, 1000 ml of water was added and stirred and left overnight. Suction filtration gave a white powdery solid. The white powdery solid was taken up in 200 ml THF, dried over 50 g anhydrous MgSO ₄ , filtered with suction and the filtrate was rotoevaporated to give an oily viscous in a rotovap bottle. The viscous material was put into 150 ml of anhydrous methanol and precipitated while stirring. The resultant was suction filtered to obtain a white powdery solid. Drying at 70 ° C. for 5 hours gave 38.6 g of product. The yield was 81% and the purity exceeded 95%.

Step 4: Preparation of 1- [6- (2-thienylformyl) -9-ethylcarbazol-3-yl]-(3-cyclopentylacetone) -1-oxime acetate
A 500 ml four-necked flask was charged with 32 g of the third step product, 150 ml of dichloromethane, 11 g of acetic anhydride, stirred at room temperature for 2 hours, and then neutralized with 5% aqueous NaHCO ₃ solution. Adjusted by. The layers were separated with a separatory funnel and then washed once with 200 ml of water. It was dried over 50 g of anhydrous MgSO ₄ and the solvent was rotoevaporated to give a viscous liquid. Recrystallization gave a white solid product. Filtration and drying gave 30.5 g of the product. The yield was 87% and the purity exceeded 95%.

The structure of the product was confirmed by ¹ H-NMR spectrum, and specific characteristic results are as follows.

¹ H-NMR (CDCl ₃ , 500 MHz): δ 1.131--1.170 (2H, m, —CH ₂ —), 1.468 1.497 (3H, t, —CH ₃ ), 1.537--1.893 (9H, m, cyclo pentane), 2.281 (3H, s, -CH 3), 2.955--2.987 (2H, q, -CH 2 -), 4.401--4.444 (2H, q, -CH 2 -), 7.285--8.542 (9H , M, benzene ring).

Example 2--12:
Referring to the method shown in Example 1, the compound of Example 2--12 was prepared with the corresponding acylating agent, the corresponding aldehyde or ketone. The target compound and its ¹ H-NMR data are shown in Table 1.

Photosensitivity test The test method for photosensitivity uses Step Tablet. Step Tablet is a single plastic plate or is called a mask plate. The outer shape looks like a plastic scale, and rectangular frames are printed on it at the same interval. The number of gradations of Step Tablet is equal to the number of rectangular frames. These rectangular frames are printed with colors from colorless and transparent to shallow gray and black with a certain increase in optical density, thereby adjusting the amount of irradiation light. The lightly colored part transmits more light to the deeply colored part. The numbers before the number of gradations correspond to the colors. The smaller the number, the smaller the number of gradations and the shallower the color, the more light is transmitted and the lower the photosensitivity of the corresponding photoinitiator. The higher the number, the higher the number of gradations, the deeper the color, the smaller the amount of transmitted light, and the higher the photosensitivity of the corresponding photoinitiator.

  Specifically, the photosensitivity of the photoinitiator represented by formula (I) was tested according to the following steps.

  (1) Using the following composition as an example, a photosensitive composition containing a photoinitiator was blended.

200 parts by mass of acrylate copolymer (benzyl methacrylate / methacrylic acid / hydroxyethyl methacrylate (molar ratio: 70/10/20) copolymer (Mw: 10000))
Dipentaerythritol hexaacrylate 100 parts by weight Photoinitiator 5 parts by weight
900 parts by weight of butanone (solvent) The photoinitiator in the above composition is selected from carbazole oxime ester compounds represented by the formula (I) of the present invention or (as contrast) photoinitiators known in the prior art.

(2) Photosensitivity test The above blend was stirred under a yellow light, a fixed amount was placed on a PET template, formed into a film with a roll coater, and dried at 90 ° C for 2 minutes. A 2 μm coating film was obtained. In order to obtain a coating film having the above thickness, the coating process may be completed once, or may be performed several times.

Thereafter, it was cooled to room temperature, a mask plate having 12 gradations was attached, and the coating film was exposed to ultraviolet rays of 365 nm, 405 nm and 436 nm using a high pressure mercury lamp. The total radiation dose on the test master was measured at 1000 mJ / cm ² with an optical power meter. After exposure, the mask plate was removed, and the exposed original plate was developed using a 1% aqueous sodium carbonate solution at 30 ° C. The photosensitivity characteristic of the initiator system is the highest number of gradations retained after development (ie polymerization). The higher the number of gradations, the higher the sensitivity of the test system. The results are shown in Table 2.

  In Table 2, PBG-304 represents 1- (6-O-methylbenzoyl-9-ethylcarbazol-3-yl)-(3-cyclopentylacetone) -1-oxime acetate, a photoinitiator disclosed in CN101508744A. OXE-02 represents 1- (6-O-methylbenzoyl-9-ethylcarbazol-3-yl)-(3-ethanone) -1-oxime acetate; Irgacure369 represents 2-phenyl-2-dimethyl Amino-1-(-4-morpholinylphenyl) -butanone-1 is shown.

  As is apparent from the experimental results in Table 2, the number of gradations of the photodisclosure agent represented by the formula (I) according to the present invention is higher with the commercially available Irgacure369 and OXE-2 photoinitiators and is disclosed in CN101508744A Even higher than the carbazole oxime ester photoinitiators. That is, the carbazole oxime ester-based compound of the present invention is superior in photosensitivity (photocuring) characteristics as a photoinitiator.

  Based on the above, the carbazole oxime ester photoinitiator represented by the formula (I) according to the present invention has excellent application characteristics, extremely high photosensitivity, and light such as Irgacure369 and OXE-2 which are currently commercially available. It is superior to the initiator and also superior to the carbazole oxime ester photoinitiator disclosed in CN101508744A. When applied to a photosensitive composition, the photo-curing properties can be greatly improved, and the field of application of a highly photosensitive composition, for example, the production rate of a color filter can be significantly improved. On the other hand, higher photosensitivity indicates that the composition system can be cross-linked and cured with a lower photoinitiator concentration and / or exposure agent amount. For example, in the production of a color filter, by using the photosensitive composition containing the photoinitiator of the present invention, the production of BM can be completed with a very low amount of exposure agent.

Claims (11)

A carbazole oxime ester photoinitiator having a structure represented by the formula (1).

However,
R ₁ is

And
R ₂ is a C _{1 to} C ₂₀ linear or branched alkyl group,
Ar is a substituted aryl group having not may have a substituent O-containing heterocyclic group, or an alkylthio group or phenylthio group. 2. The carbazole oxime ester photoinitiator according to claim _1, wherein in R ₁ , n = 2, m = 3 or 4. _3. The carbazole oxime ester photoinitiator according to claim 1 or 2, wherein R ₂ is a C _{1 to} C ₅ linear or branched alkyl group . R ₂ 4. The carbazole oxime ester photoinitiator according to claim 3, wherein is a methyl, ethyl, n-propyl, or n-butyl. R ₂ 5. The carbazole oxime ester photoinitiator according to claim 4, wherein is ethyl. Wherein a substituent is O-containing heterocyclic group that is O-containing heterocyclic group but it may also have a 0-2 substituents, carbazole oxime according to any one of claims 1 to 5 Ester photoinitiator. 7. The carbazole oxime ester photoinitiator according to claim 6 , wherein the 0 to 2 substituents are 0 to 2 methyl or ethyl. Before Symbol O-containing heterocyclic group is a furyl group, carbazole oxime ester photoinitiator according to any one of claims 1-7. The carbazole oxime ester photoinitiator according to any one of claims 1 to 8 , wherein the Ar group is a kind selected from the following structures.

The method for producing a carbazole oxime ester photoinitiator according to any one of claims 1 to 9 , comprising the following steps.
(1) Substitution reaction: Dissolve carbazole in an organic solvent and perform substitution reaction with R ₂ -Br, which is a brominated hydrocarbon, to obtain intermediate a (ie, 9-R ₂ carbazole). The reaction process is as follows.

(2) Acylation reaction: Intermediate a is dissolved in an organic solvent and subjected to an acylation reaction under the action of aluminum chloride to produce intermediate b (ie 3-R ₁ acyl-6-Ar acyl-9 -R ₂ carbazole). The reaction process is as follows.

(3) the oximation reaction: From the obtained intermediate b, through oximation reaction, intermediate c (i.e., 1-(6-Ar acyl -9-R _{2-carbazolyl)} -1-R ₁ ketoxime) a obtain. The reaction process is as follows.

(4) Esterification reaction: A target product (that is, a carbazole oxime ester photoinitiator represented by the formula (I)) is obtained by an esterification reaction between the obtained intermediate c and acetic anhydride. The reaction process is as follows.

Use of the carbazole oxime ester photoinitiator according to any one of claims 1 to 9 in a photosensitive composition.