Sulphide-modified anthraquinone dyes, process for their synthesis and use thereof

Abstract

This invention discloses thioether-modified anthraquinone dyes, their synthesis method, and their application in color photoresist pastes. The preparation process of the anthraquinone dyes is as follows: 1,8-dichloroanthraquinone is reacted with a substituent-containing arylthiophenol at 100 °C using N,N-dimethylformamide (DMF) as a solvent in the presence of alkali K₂CO₃ via an aromatic nucleophilic substitution (SnAr) reaction. This invention introduces thioether-modified anthraquinone yellow dye molecules into the application of color photoresist pastes. These molecules are used as additives for green pixels in photoresist pastes to absorb stray blue light, thereby improving the color purity of green pixels. The thioether-modified anthraquinone yellow dyes of this invention have better solubility than traditional anthraquinone dye molecules and retain the excellent photostability and thermal stability of the anthraquinone backbone, showing significant advantages over commonly used yellow dyes in current photoresist pastes.

Description

Technical Field

[0001] This invention relates to the field of color photoresist technology, specifically to a method for preparing thioether-modified anthraquinone derivatives and their application as yellow dyes in color photoresist pastes. Background Technology

[0002] In the field of display manufacturing, color filters are crucial to display performance. Currently, most commercially available color filters are prepared using pigment nano-dispersion systems. However, traditional pigments have low solubility and tend to form large clusters in photoresist, causing light scattering and resulting in decreased contrast, making it difficult to meet the requirements of high-performance display devices.

[0003] In the fabrication of color filters, yellow dyes are often used as a key additive for green pixels to precisely filter stray light in the blue light band, thereby improving the color purity of green pixels. While commonly used azo dyes have high absorption coefficients, the thermal and photostable stability of the azo double bond (-N=N-) makes them prone to decomposition during the high-temperature baking process in color filter fabrication and under long-term backlight irradiation, resulting in significant color differences and affecting the lifespan of display devices.

[0004] Anthraquinone dyes possess a highly delocalized cyclic aromatic hydrocarbon structure with a rigid skeleton and excellent photothermal stability. They can withstand high-temperature post-baking and maintain color consistency under prolonged light irradiation. However, current applications of anthraquinone structures are mainly concentrated in blue pigment pastes (such as the amino-substituted anthraquinone structures developed by Sumitomo and Mitsubishi), while their application in high-performance yellow pigment pastes remains relatively unexplored.

[0005] Traditional anthraquinone structures have strong intermolecular forces and high lattice energy, resulting in extremely poor solubility in commonly used photoresist solvents (such as PGMEA), which easily lead to particle defects. Summary of the Invention

[0006] This invention introduces various substituted aromatic groups at the 1,8 positions of the anthraquinone backbone via thioether bonds, effectively regulating the optical properties and solubility of the molecule. Introducing this thioether-modified anthraquinone yellow dye into a photoresist color paste system not only solves the problem of poor photothermal stability of traditional yellow dyes but also exhibits excellent dispersibility and compatibility, significantly improving the color purity of green pixels in the photoresist, thereby enhancing the display performance of display devices.

[0007] This invention aims to address the technical deficiencies of yellow photoresist color paste dye molecules mentioned in the background art, and provides a thioether-modified anthraquinone yellow dye for use in color paste systems. This type of dye molecule forms a thioether through an aromatic nucleophilic substitution reaction between a substituent-containing thiophenol or mercaptopyridine and 1,8-dichloroanthraquinone. Based on traditional anthraquinone dyes, substituents are introduced into the aromatic ring, and the optical properties and solubility in PGMEA are adjusted through electronic and steric effects, while retaining the excellent photostability and thermal stability of anthraquinone dyes.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0009] A thioether-modified anthraquinone dye has the following chemical structural formula A:

[0010]

[0011] In the aforementioned chemical structural formula, Ar is selected from substituted or unsubstituted C6-C6. 20 aryl, or substituted or unsubstituted C6-C 20 Heteroaryl. The substitution refers to the replacement of one or more hydrogen atoms on the above-mentioned aryl or heteroaryl group with a group selected from the following: C1-C6 straight-chain or branched alkyl, ester, methoxy, halogen atom F, Cl, Br.

[0012] Preferably, the number of substituents is one or two, and the substitution positions are selected from the ortho or para positions.

[0013] Preferably, Ar refers to a phenyl group containing an alkyl substituent.

[0014] More preferably, Ar refers to any one of 4-methylphenyl, 4-tert-butylphenyl, and 2,4-dimethylphenyl.

[0015] To obtain the aforementioned target anthraquinone yellow dye molecule A, this invention provides a synthetic method comprising: mixing 1,8-chloroanthraquinone with substituted aromatic thiophenol in an organic solvent in the presence of a moderately strong base K2CO3 to carry out an aromatic nucleophilic substitution reaction; and preparing the target dye product by post-treatment after the reaction is completed.

[0016] Preferably, the organic solvent is N,N-dimethylformamide (DMF).

[0017] Furthermore, the aromatic nucleophilic substitution reaction is carried out at a temperature of 80-130 °C for a time of 4-8 h.

[0018] Furthermore, the post-processing step is as follows: after cooling the reaction system, deionized water is added to the reaction system, a large amount of orange-yellow solid is precipitated, after filtration, the filter residue is washed with deionized water and methanol, the crude product is pulped, then filtered and dried to obtain yellow or orange crystalline powder, which is the target dye product.

[0019] Preferably, the molar ratio of 1,8-dichloroanthraquinone to aromatic thiophenol and K2CO3 in the reaction process is 1:2.2:2.2 to 1:2.5:2.5.

[0020] More preferably, the aromatic nucleophilic substitution reaction is carried out at a temperature of 80–100 °C for 4 h.

[0021] Preferably, the substituted aromatic thiophenol is selected from any one of 4-methylthiophenol, 4-tert-butylthiophenol, and 2,4-dimethylthiophenol.

[0022] As another aspect of the present invention, the present invention also provides the application of the thioether-modified anthraquinone dye, wherein the anthraquinone dye is used as a yellow dye in colored photoresist paste.

[0023] Compared with existing yellow photoresist color paste dye technology, the thioether-modified anthraquinone yellow dye molecule of the present invention has the following superior properties:

[0024] (1) Compared with existing yellow photoresist color paste dyes, such as azo dyes, the present invention uses an anthraquinone skeleton, which retains its excellent photostability and thermal stability, can withstand the high temperature process of more than 230 °C required in the preparation of color filters, and is not prone to photochemical degradation under long-term backlight irradiation.

[0025] (2) Compared with traditional anthraquinone dyes, this invention introduces a variety of alkyl or other substituents into the aryl Ar linked by sulfide, which not only flexibly adjusts its molecular optical properties as a photoresist color paste dye, but also improves its solubility in commonly used photoresist solvents (such as PGMEA), thus solving the problem of traditional anthraquinone dyes being prone to precipitation due to poor solubility.

[0026] (3) As an additive for green pixels, the dye can filter the scattered light in the blue light band; as a dye, it can dissolve in molecular state, which can avoid the occurrence of scattering phenomenon, greatly improve the brightness and contrast of color filter, and fill the gap in the application of anthraquinone dyes in the field of yellow photoresist color paste.

[0027] (4) The synthesis method provided by the present invention has simple steps, efficient purification method, wide range of raw material sources, low cost, and is conducive to large-scale production, and has broad market application prospects. Attached Figure Description

[0028] Figure 1 The compound A1 prepared in Example 1 of this invention 1 H-NMR spectrum;

[0029] Figure 2 The compound A2 prepared in Example 2 of this invention 1 H-NMR spectrum;

[0030] Figure 3 The compound A3 prepared in Example 3 of this invention 1 H-NMR spectrum;

[0031] Figure 4 Compound A4 prepared in Comparative Example 1 of this invention 1 H-NMR spectrum; Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them, and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] Example 1 (Synthesis of compound A1)

[0034] 1,8-Dichloroanthraquinone (5.54 g, 20 mmol) and K₂CO₃ powder (6.22 g, 45 mmol) were added to a 250 mL single-necked round-bottom flask equipped with a stirrer and a reflux condenser. 80 mL of N,N-dimethylformamide (DMF) was added as a solvent, followed by 4-methylthiophenol (5.58 g, 45 mmol). The reaction system was heated to 100 °C and reacted for 5 h. After cooling to room temperature, approximately 150 mL of deionized water was added to the reaction system, immediately precipitating a large amount of orange-yellow solid. After filtration, the filter residue was washed three times each with deionized water and methanol. The obtained orange-yellow crude solid was added to approximately 50 mL of dichloromethane for slurrying, followed by filtration and drying to obtain 7.32 g of yellow thioether-modified anthraquinone compound A1 solid, with a yield of 80.5%.

[0035] The chemical structural formula of compound A1 is as follows:

[0036]

[0037] The compound A1 1 The H-NMR spectrum is shown below. Figure 1 .

[0038] Example 2 (Synthesis of compound A2)

[0039] In a 250 mL single-necked round-bottom flask equipped with a stirrer and a reflux condenser, 1,8-dichloroanthraquinone (5.54 g, 20 mmol) and K₂CO₃ powder (6.22 g, 45 mmol) were added, along with 80 mL of N,N-dimethylformamide (DMF) as a solvent. Then, 4-tert-butylthiophenol (7.76 mL, 7.48 g, 45 mmol) was added, and the reaction mixture was heated to 100 °C for 4 h. After cooling to room temperature, approximately 150 mL of deionized water was added to the reaction mixture, immediately precipitating a large amount of orange-yellow solid. After filtration, the residue was washed three times with deionized water and methanol, respectively. The obtained orange-yellow crude solid was then slurried in approximately 50 mL of dichloromethane, followed by filtration and drying to obtain 6.47 g of yellow thioether-modified anthraquinone compound A2 solid, with a yield of 60.0%.

[0040] The chemical structural formula of compound A2 is as follows:

[0041]

[0042] The compound A2 1 The H-NMR spectrum is shown below. Figure 2 .

[0043] Example 3 (Synthesis of compound A3)

[0044] 1,8-Dichloroanthraquinone (2.27 g, 8.2 mmol) and K₂CO₃ powder (2.49 g, 18 mmol) were added to a 250 mL single-necked round-bottom flask equipped with a stirrer and a reflux condenser. 50 mL of N,N-dimethylformamide (DMF) was added as a solvent, followed by 2,4-dimethylthiophenol (2.44 mL, 2.49 g, 18 mmol). The reaction system was heated to 100 °C and reacted for 4 h. After cooling to room temperature, approximately 150 mL of deionized water was added to the reaction system, immediately precipitating a large amount of orange-yellow solid. After filtration, the filter residue was washed three times with deionized water and methanol, respectively. The obtained orange-yellow crude solid product was added to approximately 30 mL of dichloromethane for slurrying, followed by filtration and drying to obtain 2.45 g of yellow thioether-modified anthraquinone compound A3 solid, with a yield of 62.2%.

[0045] The chemical structural formula of compound A3 is as follows:

[0046]

[0047] The compound A3 1The H-NMR spectrum is shown below. Figure 3 .

[0048] Comparative Example 1 (Synthesis of Compound A4)

[0049] In a 250 mL single-necked round-bottom flask equipped with a stirrer and a reflux condenser, 5.54 g (20 mmol) of 1,8-dichloroanthraquinone and 6.22 g (45 mmol) of K₂CO₃ powder were added, along with 80 mL of N,N-dimethylformamide (DMF) as a solvent. Then, 5.00 g (45 mmol) of 4-mercaptopyridine was added, and the reaction mixture was heated to 100 °C for 4 h. After cooling to room temperature, approximately 150 mL of deionized water was added to the reaction mixture, immediately precipitating a large amount of orange-yellow solid. After filtration, the residue was washed three times with deionized water and methanol, respectively. The obtained orange-yellow crude solid was then slurried in approximately 50 mL of dichloromethane, followed by filtration and drying to obtain 7.20 g of yellow sulfide-modified anthraquinone compound A4 solid, with a yield of 84.0%.

[0050] The chemical structural formula of compound A4 is as follows:

[0051]

[0052] The compound A4 1 The H-NMR spectrum is shown below. Figure 4 .

[0053] Effect Experiment Example

[0054] I. Determination of UV-Vis absorption spectra of yellow thioether-modified anthraquinone dye molecules

[0055] The anthraquinone dyes prepared in Examples 1-3 and Comparative Example 1 were formulated into 30 μmol / L solutions using propylene glycol methyl ether acetate (PGMEA) as the solvent, and their absorption spectra were measured using a UV-Vis spectrophotometer. The molar extinction coefficient of the dyes was calculated using the following formula:

[0056] Α = εcl

[0057] In the formula, A is the absorbance intensity; ε is the molar extinction coefficient, L·mol⁻¹ -1 ·cm -1 c is the concentration, mol·L⁻¹ -1 ; l is the thickness of the absorption layer, in cm.

[0058] The UV-Vis absorption spectra of the anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0059] Table 1. UV-Vis absorption spectra of the anthraquinone dyes modified with thioethers prepared in Examples 1-3 and Comparative Example 1

[0060]

[0061] As shown in Table 1, the anthraquinone dye molecules prepared in Examples 1, 2, and 3 have alkyl substituents with 1 to 4 carbon atoms on Ar, exhibiting similar maximum absorption wavelengths. They also show a significant red shift compared to Comparative Example 1, which has a pyridine ring containing electron-withdrawing atoms on Ar. Furthermore, the anthraquinone dye molecule prepared in Example 2, containing a larger 4-tert-butyl substituent, has the highest molar absorptivity. In addition, the absorption wavelength range of the above anthraquinone dyes is all between 430 and 450 nm, allowing for precise absorption of stray blue light in this band.

[0062] II. Solubility Test of Anthraquinone Dye Molecules

[0063] The solubility of anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 in PGMEA and N-methylpyrrolidone (NMP) was tested. A certain amount of dye and organic solvent were weighed, sonicated at room temperature for 10 min, and allowed to stand for 24 h. The mixture was then filtered three times using a filter membrane. The filtrate was dried, and the solubility S of the dye was calculated.

[0064] S = 100M S / M L

[0065] In the formula, M S This refers to the mass of the dye after drying, in grams (g); in milliliters (M). L This is the mass of the solution, in grams (g).

[0066] The solubility test results of the anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are shown in Table 2.

[0067] Table 2. Solubility test results of thioether-modified anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1.

[0068]

[0069] As shown in Table 2, compared with Comparative Example 1, the anthraquinone dye molecules containing alkyl-substituted phenyl groups prepared in Examples 1-3 all have better solubility in PGMEA and NMP, among which the anthraquinone dye molecules prepared in Example 3 have the best solubility in PGMEA and NMP.

[0070] III. Thermal stability testing of thioether-modified anthraquinone dye molecules

[0071] The fabrication of color filters involves a post-baking process at 230 °C or higher, as industrial applications require dye molecules to exhibit good thermal stability at this temperature. Thermogravimetric analysis (TGA) was used to evaluate the thermal stability of synthetic dyes. Under nitrogen protection, the synthetic dyes were heated from room temperature to 500 °C at a rate of 10 °C / min to determine their thermal decomposition temperature T. d .

[0072] The thermal stability test results of the thioether-modified anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are shown in Table 3.

[0073] Table 3. Thermal stability test results of the anthraquinone dye molecules modified with thioethers prepared in Examples 1-3 and Comparative Example 1

[0074]

[0075] As shown in Table 3, the T values ​​of the anthraquinone dye molecules prepared in Examples 1-3 and Comparative Example 1 are... d Within the temperature range of 330~372℃, the weight loss rate at 230℃ is less than 2%, indicating that the above-mentioned thioether-modified anthraquinone dyes retain the excellent thermal stability of traditional anthraquinone dyes.

[0076] This invention designs a novel class of thioether-modified anthraquinone dye compounds for use as a key additive in the green pixels of color filters. This dye can significantly absorb stray blue light in the 430–450 nm range, significantly improving the color purity of the green pixels. In addition, it possesses the following excellent properties: outstanding optical performance, excellent dispersibility, and significantly improved solubility compared to traditional anthraquinones. Furthermore, this compound exhibits outstanding thermal and photostability. Regarding the preparation process, the operation procedure developed in this invention is simple, efficient, and inexpensive, making it very suitable for large-scale industrial production.

[0077] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A thioether-modified anthraquinone dye, characterized in that, Its chemical structural formula A is as follows: ； In the chemical structural formula, Ar is selected from substituted or unsubstituted C6-C6. 20 aryl, or substituted or unsubstituted C6-C 20 Mixed aromatic compounds.

2. The anthraquinone dye modified with thioether as described in claim 1, characterized in that, Ar refers to a phenyl group containing an alkyl substituent.

3. The anthraquinone dye modified with thioether as described in claim 1, characterized in that, The Ar is selected from any one of 4-methylphenyl, 4-tert-butylphenyl, and 2,4-dimethylphenyl.

4. A method for synthesizing a thioether-modified anthraquinone dye as described in any one of claims 1-3, characterized in that, include: In an organic solvent, in the presence of a moderately strong base K2CO3, 1,8-chloroanthraquinone and substituted aromatic thiophenols are mixed to carry out an aromatic nucleophilic substitution reaction. After the reaction is completed, the target dye product is prepared by post-treatment.

5. The method for synthesizing a thioether-modified anthraquinone dye as described in claim 4, characterized in that, The aromatic nucleophilic substitution reaction is carried out at a temperature of 80-130 °C for 4-8 h.

6. The method for synthesizing a thioether-modified anthraquinone dye as described in claim 4, characterized in that, The post-processing steps are as follows: after cooling the reaction system, deionized water is added to the reaction system, a large amount of orange-yellow solid is precipitated, after filtration, the filter residue is washed with deionized water and methanol, the crude product is pulped, then filtered and dried to obtain yellow or orange crystalline powder, which is the target dye product.

7. The method for synthesizing a thioether-modified anthraquinone dye as described in claim 4, characterized in that, In the reaction process, the molar ratio of 1,8-dichloroanthraquinone to aromatic thiophenol and K2CO3 is 1:2.2:2.2 to 1:2.5:2.

5.

8. The method for synthesizing a thioether-modified anthraquinone dye as described in claim 4, characterized in that, The reaction temperature is 80–100 °C, and the reaction time is 4 h.

9. The method for synthesizing a thioether-modified anthraquinone dye as described in claim 4, characterized in that, The substituted aromatic thiophenol is selected from any one of 4-methylthiophenol, 4-tert-butylthiophenol, and 2,4-dimethylthiophenol.

10. The application of the thioether-modified anthraquinone dye according to claim 1, wherein the anthraquinone dye is used as a yellow dye in colored photoresist paste.

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