Photosensitizer, positive polyimide photosensitive resin composition containing same, polyimide cured film and display device

Abstract

The invention discloses a photosensitizer, a positive polyimide photosensitive resin composition containing the photosensitizer, a polyimide cured film and a display device. The structural general formula of the photosensitizer is as shown in formula I; r1, R2 and R3 respectively and independently represent a divalent organic group with the carbon atom number of 1 to 10; d represents H or a group shown in a formula II, and at least one D represents the group shown in the formula II. By adding the photosensitizer developed by the invention into the positive polyimide photosensitive resin composition, the transmittance of the prepared cured film can be effectively improved, and meanwhile, the photoetching sensitivity of the cured film and the cured residual film rate after photoetching can be kept. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of photosensitizer materials. More specifically, it relates to a photosensitizer, a positive polyimide photosensitive resin composition containing the same, a polyimide cured film, and a display device. Background Art

[0002] With the development of display technology, especially the application of under-screen camera technology, higher requirements are put forward for the transmittance and yellowness of display materials. The film layers formed after thermal curing of the photosensitive polyimide (PSPI) lithography materials commonly used in the planarization layer and pixel definition layer of display panels have insufficient transmittance in the visible light region, and often there is a significant light yellow color of the polyimide material - the yellowness value is too high.

[0003] Currently, there are many factors leading to the yellowing of polyimide photoresist during curing. One important factor is that during the curing process of the photosensitive adhesive layer, the non-photosensitive part reacts with other components such as photosensitive resin and functional additives to cause yellowing. The reaction mainly occurs because the structure of the commonly used photosensitizer is mostly a polyphenyl structure with many benzene rings. This structure is prone to cause intramolecular and intermolecular conjugation effects when the photoresist finally forms a film, resulting in serious yellowing of the cured photoresist film and reducing the transmittance of the cured film layer within the visible light wavelength range.

[0004] Therefore, there is an urgent need to develop a polyimide photosensitizer material with high transmittance and a smaller yellowness value in the visible light range (400 - 780 nm) to support the higher technical application requirements in the display field. Summary of the Invention

[0005] To solve the above problems, the first object of the present invention is to provide a photosensitizer. The photosensitizer can effectively inhibit the yellowing reaction, improve the transmittance of the polyimide cured film. Especially when it is applied at a wavelength of 400 nm, its transmittance can be increased to more than 85%, and while increasing the transmittance, it can also maintain the lithographic sensitivity and the cured residue film rate after lithography.

[0006] The second object of the present invention is to provide a highly transparent positive polyimide photosensitive resin composition containing the above-mentioned photosensitizer.

[0007] The third object of the present invention is to provide a photosensitive polyimide cured film.

[0008] The fourth object of the present invention is to provide a display device containing the above-mentioned polyimide cured film.

[0009] To achieve the above first object, the present invention adopts the following technical solutions:

[0010] The present invention discloses a photosensitizer, and the structural general formula of the photosensitizer is shown as Formula I;

[0011]

[0012] In Formula I,

[0013] R1, R2, and R3 each independently represent a divalent organic group having 1 to 10 carbon atoms;

[0014] D represents H or a group shown in Formula II, and at least one D represents a group shown in Formula II.

[0015] Furthermore, R1, R2, and R3 each independently represent a divalent organic group having 1 to 3 carbon atoms. Preferably, R1, R2, and R3 each independently represent an alkylene group having 1 to 3 carbon atoms.

[0016] Furthermore, D represents a group shown in Formula II.

[0017] Furthermore, R1, R2, and R3 represent the same group.

[0018] Furthermore, the photosensitizer is selected from one of the structures shown in the following Formulas I1 to I12:

[0019]

[0020]

[0021] To achieve the above second object, the present invention adopts the following technical solution:

[0022] The present invention discloses a highly transparent positive polyimide photosensitive resin composition. By weight, the polyimide photosensitive resin composition comprises

[0023] 10 - 35 parts of a photosensitizer composition;

[0024] 95 - 105 parts of a polyimide-based resin;

[0025] 15 - 25 parts of a crosslinking agent;

[0026] 0.5 - 5 parts of a leveling agent;

[0027] 0.1 - 2 parts of an adhesive;

[0028] wherein, the photosensitizer composition includes at least two photosensitizers as described above.

[0029] Furthermore, the solid content of the polyimide photosensitive resin composition is 8% - 20%.

[0030] Further, the photosensitizer composition is a mixture, and the effect of inhibiting the yellowing reaction is also affected by the composition of the photosensitizer composition. In a specific embodiment, the composition of the photosensitizer composition is restricted according to the proportional relationship of different groups. When the molar ratio of the group of formula II to H is 1:1 - 5:1, the effect of inhibiting the yellowing reaction is significant. Exemplarily, the molar ratio of the group of formula II to H can be 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0031] Further, the composition of the photosensitizer composition can also be restricted according to the preparation method. The following exemplarily provides a preparation method of the photosensitizer composition, including the following steps:

[0032] Under a nitrogen atmosphere, dissolve the compound of formula I-1 and 5-naphthoquinone diazosulfonyl chloride in an organic solvent. At room temperature, dropwise add an organic solvent in which triethylamine is dispersed thereto, and control the temperature in the reaction system during the dropping process not to exceed 35°C. After the dropping is completed, stir and react at room temperature for 1.5 - 2.5 h, filter, pour the filtrate into water, then filter out the precipitate, and dry the precipitate to obtain the product;

[0033] Among them, the compound of formula I-1 is selected from the following structures:

[0034]

[0035] R1, R2, and R3 each independently represent a divalent organic group having 1 - 10 carbon atoms.

[0036] In the above preparation method of the photosensitizer composition, mainly affecting the group selection of R1, R2, and R3 in the structure of the compound of formula I by changing the structure of the compound of formula I-1, and mainly affecting the molar ratio of the group of formula II to H in the photosensitizer composition by adjusting the molar ratio of the compound of formula I-1 and 5-naphthoquinone diazosulfonyl chloride.

[0037] Further, the molar ratio of the compound of formula I-1 to 5-naphthoquinone diazosulfonyl chloride is 1:1.5 - 1:7; Exemplarily, the molar ratio of the compound of formula I-1 to 5-naphthoquinone diazosulfonyl chloride can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, etc.

[0038] Further, the addition amount of triethylamine and the molar ratio of 5-naphthoquinone diazosulfonyl chloride is 1:1.

[0039] Further, the organic solvent is selected from one of 1,4-dioxane and dioxane.

[0040] Further, the photosensitive polyimide-based resin is selected from one or more of polyimide, polyimide precursor, polyamideimide, polyamideimide precursor, and polyetherimide. Among these photosensitive polyimide-based resins, from the aspects of high development adhesion, excellent heat resistance, and low outgassing amount at high temperature, resulting in high long-term reliability when the cured film described later is used in display devices, it is preferably one or more selected from the group consisting of polyimide, polyimide precursor, polyetherimide, and their copolymers, and particularly preferably polyimide, polyimide precursor, or their copolymers. In addition, from the aspect of further improving sensitivity, it is more preferably polyimide. Here, the polyimide precursor refers to a resin that is converted into polyimide through heat treatment or chemical treatment. For example, polyamic acid, polyamic acid ester, etc. can be cited.

[0041] The photosensitive polyimide-based resin can be synthesized by a known method. As the manufacturing method, for example, the following methods can be cited for synthesis: 1) a method of reacting an acid dianhydride with a diamine compound at low temperature; 2) a method of partially esterifying the amic acid structure with N,N-dimethylformamide dimethylacetate or the like after reacting an acid dianhydride with a diamine compound at low temperature; 3) a method of obtaining a diester from an acid dianhydride and an alcohol, and then reacting it with an amine in the presence of a condensing agent; 4) a method of obtaining a diester from an acid dianhydride and an alcohol, then acyl chlorinating the remaining dicarboxylic acid, and reacting it with an amine, etc.

[0042] Examples of the acid dianhydrides used for polyimide, polyimide precursor, and their copolymers include: pyromellitic dianhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,3,3′,4′-biphenyltetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride,  3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 2,2′,3,3′-benzophenone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 9,9-bis{4-(3,4-dicarboxyphenoxy)phenyl}fluorene dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and other aromatic tetracarboxylic dianhydrides, butane tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride and other aliphatic tetracarboxylic dianhydrides, etc. Two or more of these can also be used.

[0043] Specific examples of the diamine compound include, by way of example: 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, benzidine, m-phenylenediamine, p-phenylenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, bis(4-aminophenoxy)biphenyl, bis{4-(4-aminophenoxy)phenyl}ether, 1,4-bis(4-aminophenoxy)benzene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 2,2′,3,3′-tetramethyl-4,4′-diaminobiphenyl, 3,3′,4,4′-tetramethyl-4,4′-diaminobiphenyl, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl, 9,9-bis(4-aminophenyl)fluorene, or a compound in which at least a part of the hydrogen atoms of these aromatic rings is substituted by an alkyl group or a halogen atom, or an aliphatic cyclohexylenediamine, methylenebis(cyclohexylamine), and a diamine having the structure shown below, etc. Two or more of these may also be used.

[0044] Furthermore, the crosslinking agent in the present invention is a thermally crosslinkable compound, and examples thereof include compounds having a benzoxazine structure, compounds having an epoxy structure, compounds having an oxetane structure, and compounds having an alkoxymethyl group, and they can also be used in combination. Among them, a compound having a benzoxazine structure is preferred because: the compound having a benzoxazine structure undergoes a crosslinking reaction based on a ring-opening addition reaction, so no degassing due to curing occurs, and the shrinkage caused by heat is small, so the generation of warpage can be suppressed.

[0045] Preferred examples of the compound having a benzoxazine structure include B-a type benzoxazine, B-m type benzoxazine (above, trade names, manufactured by Shikoku Kasei Kogyo), a benzoxazine adduct of a polyhydroxystyrene resin, a linear phenolic (phenol novolak) type dihydrobenzoxazine compound, etc. They can be used alone or in combination of two or more.

[0046] As preferred examples of the compound having an epoxy structure, for example, Epiclon 850-S, Epiclon HP-4032, Epiclon HP-7200, Epiclon HP-820, Epiclon HP-4700, Epiclon EXA-4710, Epiclon HP-4770, Epiclon EXA-859CRP, Epiclon EXA-4880, Epiclon EXA-4850, Epiclon EXA-4816, Epiclon EXA-4822 (above, trade names, manufactured by Dainippon Ink and Chemicals, Inc.), Rikaresin BPO-20E, Rikaresin BEO-60E (above, trade names, manufactured by Shin Nippon Rika Co., Ltd.), EP-4003S, EP-4000S (above, trade names, manufactured by ADEKA), etc. can be mentioned. They can be used alone or in combination of two or more.

[0047] As the compound having an oxetane structure, compounds having two or more oxetane rings in one molecule, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, 3-ethyl-3-(2-ethylhexylmethyl)oxetane, 1,4-benzenedicarboxylic acid-bis[(3-ethyl-3-oxetanyl)methyl]ester, etc. can be cited. As preferred examples, ARON OXETANE series manufactured by Toagosei Co., Ltd. can be used. They can be used alone or in combination of two or more.

[0048] As preferred examples of the compound having an alkoxymethyl group, for example, DML-PC, DML-PEP, DML-OC, DML-OEP, DML-34X, DML-PTBP, DML-PCHP, DML-OCHP, DML-PFP, DML-PSBP, DML-POP, DML-MBOC, DML-MBPC, DML-MTrisPC, DML-BisOC-Z, DML-BisOCHP-Z, DML-BPC, DML-BisOC-P, DMOM-PC, DMOM-PTBP, DMOM-MBPC, TriML-P, TriML-35XL, TML-HQ, TML-BP, TML-pp-BPF, TML-BPE, ML-BPA, TML-BPAF, TML-BPAP, TMOM-BP, TMOM-BPE, TMOM-BPA, TMOM-BPAF, TMOM-BPAP, HML-TPPHBA, HML-TPHAP, HMOM-TPPHBA, HMOM-TPHAP (the above are trade names, manufactured by Honshu Chemical Industry Co., Ltd.), NIKALAC MX-290, NIKALAC MX-280, NIKALAC MX-270, NIKALAC MX-279, NIKALAC MW-100LM, NIKALAC MX-750LM (the above are trade names, manufactured by Sanwa Chemical Co., Ltd.) can be used alone or in combination of two or more.

[0049] Furthermore, the leveling agent can improve the wettability between the positive polyimide photosensitive resin composition and the substrate. In a specific embodiment, the leveling agent is selected from surfactants, ester compounds such as ethyl lactate or propylene glycol monomethyl ether acetate, alcohol compounds such as ethanol, ketone compounds such as cyclohexanone or methyl isobutyl ketone, and ether compounds such as tetrahydrofuran or dioxane.

[0050] Furthermore, the adhesive can improve the adhesion between the positive polyimide photosensitive resin composition and the substrate. Without compromising the effect of storage stability, some silane coupling agents such as aminopropyltrimethoxysilane, trimethoxyepoxysilane, vinyltrimethoxysilane, and mercaptopropyltrimethoxysilane can be added as adhesives. In addition, as needed, without reducing the shrinkage residual film rate after curing, some compounds with phenolic hydroxyl groups can be added. By adding these compounds, the development time can be adjusted and scum can be improved. In a specific embodiment, examples of the compounds with phenolic hydroxyl groups include Bis-Z, BisP-EZ, TekP-4HBPA, TrisP-HAP, TrisP-PA, BisOCHP-Z, BisP-MZ, BisP-PZ, BisP-IPZ, BisOCP-IPZ, BisP-CP, BisRS-2P, BisRS-3P, BisP-OCHP, Methylenetris-FR-CR, BisRS-26X (above, trade names, manufactured by Nippon Kayaku Co., Ltd.), BIP-PC, BIR-PC, BIR-PTBP, BIR-BIPC-F (above, trade names, manufactured by Asahi Organic Materials Co., Ltd.), novolak resins, etc. Two or more of the above compounds can also be contained.

[0051] To achieve the above third object, the present invention adopts the following technical solutions:

[0052] The present invention discloses a photosensitive polyimide cured film, which is obtained by dissolving the above-mentioned positive polyimide photosensitive resin composition and coating it on a substrate, and then curing it.

[0053] To achieve the above fourth object, the present invention adopts the following technical solutions:

[0054] The present invention discloses a display device, which includes the above-mentioned polyimide cured film.

[0055] The beneficial effects of the present invention are as follows:

[0056] The present invention provides a photosensitizer and a positive polyimide photosensitive resin composition containing the same. The photosensitizer can effectively inhibit the yellowing reaction and improve the transmittance of the polyimide cured film. Especially when it is applied at a wavelength of 400 nm, the transmittance can be increased to more than 85%, and while increasing the transmittance, it can also maintain the lithographic sensitivity and the cured residual film rate after lithography. Description of the Drawings

[0057] Figure 1 It is the liquid phase chromatogram of Synthesis Example A1. Detailed Embodiments

[0058] To illustrate the present invention more clearly, the following further describes the present invention in conjunction with preferred embodiments. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0059] Photosensitizer composition

[0060] Synthesis Example A1

[0061]

[0062] Under a nitrogen stream, 13.05 g (0.05 mol) of 1,3,5-tris(2-hydroxyethyl) cyanuric acid (CAS: 839-90-7) and 37.60 g (0.14 mol) of 5-naphthoquinone diazosulfonyl chloride (CAS: 3770-97-6) were dissolved in 450 mL of 1,4-dioxane (which can also be replaced by dioxane). After returning to room temperature, 14.17 g (0.14 mol) of triethylamine mixed with 50 mL of 1,4-dioxane was added dropwise thereto, and the temperature in the reaction system during the dropping process was controlled not to exceed 35°C. After the dropping was completed, it was stirred at 30°C for 2 hours, the triethylamine salt was filtered, the filtrate was poured into water, and then the precipitate was filtered out. The precipitate was dried with a vacuum dryer to obtain the photosensitizer composition.

[0063] The prepared photosensitizer composition was subjected to liquid phase testing, and the test conditions and test equipment information are as follows:

[0064] Equipment: Agilent 1290 Infinity II high performance liquid chromatography.

[0065] Chromatographic column: Discovery C18 250 mm * 4.6 mm, 5 μm.

[0066] Wavelength: 343 nm.

[0067] Mobile phase: Acetonitrile: water = 1:1 (-15 min-).

[0068] Injection volume: 9 μL.

[0069] Flow rate: 1.0 ml / min.

[0070] After testing, it was determined that the photosensitizer composition contained one monosubstituted product with D selected from the structure of Formula II, two disubstituted products with D selected from the structure of Formula II, and three trisubstituted products with D selected from the structure of Formula II, and the specific proportions are shown in Table 1. Finally, it was determined that in the photosensitizer composition, the molar ratio of the group of Formula II to H was approximately 2:1.

[0071] Table 1

[0072] Component Retention time / min Peak height Peak area Percentage of peak area / % Monosubstituted product 10.602 178.973 3797.793 26.49 Disubstituted product 22.997 542.05 6780.221 47.29 Trisubstituted product 26.766 544.466 3758.3169 26.22

[0073] Synthesis Example A2

[0074]

[0075] Under a nitrogen stream, 13.05 g (0.05 mol) of N`N`N-trihydroxyisocyanuric acid (CAS: 143435-52-3) and 37.60 g (0.14 mol) of 5-naphthoquinone diazosulfonyl chloride (CAS: 3770-97-6) were dissolved in 450 mL of 1,4-dioxane (which can also be replaced by dioxane). After returning to room temperature, 35.43 g (0.35 mol) of triethylamine mixed with 50 mL of 1,4-dioxane was added dropwise thereto, and the temperature in the reaction system during the dropwise addition was controlled not to exceed 35 °C. After the dropwise addition, the mixture was stirred at 30 °C for 2 hours, the triethylamine salt was filtered, the filtrate was poured into water, and then the precipitate was filtered out. The precipitate was dried with a vacuum dryer to obtain the photosensitizer composition. According to the test method of Synthesis Example A1, it was finally determined that in the photosensitizer composition, the molar ratio of the group of formula II to H was about 2:1.

[0076] Synthesis Example A3

[0077]

[0078] Under a nitrogen stream, 13.05 g (0.05 mol) of 1,3,5-tris(2-hydroxyethyl) cyanuric acid (CAS: 839-90-7) and 94.00 g (0.35 mol) of 5-naphthoquinone diazosulfonyl chloride (CAS: 3770-97-6) were dissolved in 1200 ml of 1,4-dioxane (which can also be replaced by dioxane). After returning to room temperature, 14.17 g (0.14 mol) of triethylamine mixed with 50 mL of 1,4-dioxane was added dropwise thereto, and the temperature in the reaction system during the dropwise addition was controlled not to exceed 35 °C. After the dropwise addition, the mixture was stirred at 30 °C for 2 hours, the triethylamine salt was filtered, the filtrate was poured into water, and then the precipitate was filtered out. The precipitate was dried with a vacuum dryer to obtain the photosensitizer composition. According to the test method of Synthesis Example A1, it was finally determined that in the photosensitizer composition, the molar ratio of the group of formula II to H was about 5:1.

[0079] Comparative Compound

[0080]

[0081] Comparative Composition

[0082] TPPA-PAC of Toyo Kasei Kogyo Co., Ltd. in Japan (purchased externally, CAS No.: 137902-98-8), the general formula structure is as follows, wherein in this comparative composition, D represents the group of formula II or H, and the molar ratio of the group of formula II to H is 5:1.

[0083]

[0084] Polyimide resin

[0085] Synthesis Example B1

[0086] Under nitrogen protection, 10 mmol of diamine monomer 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BAHF) was added to a 250 mL three-necked round-bottom flask, and then 150 mL of N-methylpyrrolidone (NMP) and 9 mmol of pyromellitic dianhydride (PMDA) were added successively. The reaction was stirred at room temperature for 3 h to obtain a viscous reaction solution. Then the temperature was raised to 40 °C, 2 mmol of m-aminophenol (MAP) was added, and then 20 mmol of N,N-dimethylformamide diethyl acetal (DMF-DEA) was slowly added dropwise. After reacting for 4 h, the reaction mixture was slowly poured into 2 L of rapidly stirred deionized water to precipitate a white powdery solid. After suction filtration, it was dried at 60 °C for 72 h to obtain PAE (R1) resin with a molecular weight of 6000 - 60000.

[0087] Synthesis Example B2

[0088] Under nitrogen protection, 10 mmol of diamine monomer 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BAHF) was added to a 250 mL three-necked round-bottom flask, and then 150 mL of N-methylpyrrolidone (NMP) and 9 mmol of 4,4'-oxybisphthalic anhydride (ODPA) were added successively. The reaction was stirred at room temperature for 3 h to obtain a viscous reaction solution. Then the temperature was raised to 40 °C, 2 mmol of m-aminophenol (MAP) was added, and then 20 mmol of N,N-dimethylformamide diethyl acetal (DMF-DEA) was slowly added dropwise. After reacting for 4 h, the reaction mixture was slowly poured into 2 L of rapidly stirred deionized water to precipitate a white powdery solid. After suction filtration, it was dried at 60 °C for 72 h to obtain PAE (R2) resin with a molecular weight of 6000 - 60000.

[0089] Synthesis Example B3

[0090] Under nitrogen protection, 10 mmol of diamine monomer 4,4'-diaminodiphenyl ether (ODA) was added to a 250 mL three-necked round-bottom flask, and then 150 mL of N-methylpyrrolidone (NMP) and 9 mmol of pyromellitic dianhydride (PMDA) were added successively. The mixture was stirred at room temperature for 3 h to obtain a viscous reaction solution. Then the temperature was raised to 40 °C, 2 mmol of m-aminophenol (MAP) was added, and then 20 mmol of N,N-dimethylformamide diethyl acetal (DMF-DEA) was slowly added dropwise. After reacting for 4 h, the reaction mixture was slowly poured into 2 L of rapidly stirred deionized water to precipitate a white powdery solid. After suction filtration, it was dried at 60 °C for 72 h to obtain PAE (R3) resin with a molecular weight of 6000 - 60000.

[0091] Positive polyimide photosensitive resin composition

[0092] Examples 1 - 12

[0093] This example provides a method for preparing a positive polyimide photosensitive resin composition. The feeding conditions of each example are shown in Table 2, and the specific preparation steps are as follows:

[0094] Under N2 protection, according to Table 2, the formulated amount of polyimide resin was added to a mixed solution of 1200 parts by mass of propylene glycol methyl ether (PGME) and γ-butyrolactone (GBL) (volume ratio of PGME:GBL = 7:3). After stirring until completely dissolved and clear, a photosensitizer composition, a crosslinking agent, a leveling agent, and an adhesive were added successively. After stirring for 30 min until completely dissolved and clear, and when the whole solution turned rose red, stirring was stopped, and the glue sample was put into a light-shielding and clean packaging bottle for storage.

[0095] Table 2 (parts by weight)

[0096]

[0097]

[0098] Comparative example

[0099] This example provides a method for preparing a positive polyimide photosensitive resin composition. The feeding conditions of each comparative example are shown in Table 3, and the specific preparation steps are the same as those in Examples 1 - 12.

[0100] Table 3 (parts by weight)

[0101]

[0102] Performance test

[0103] The positive polyimide photosensitive resin compositions prepared in Examples 1-12 and Comparative Examples 1-12 were tested as follows. The test conditions for the prepared positive polyimide photosensitive resin compositions were as follows:

[0104] 1) Evaluation of imaging ability: Using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited), different positive polyimide photosensitive resin compositions obtained were coated on a glass substrate by spin coating, and a coating was obtained after drying. Then, the coating was exposed under a mask using an i-line stepper, and then developed by soaking in 2.38 wt% tetramethylammonium hydroxide (TMAH), and washed with pure water. The etched line or groove state was detected by a scanning electron microscope (SEM). When the line or groove with a width less than 3 μm could still be clearly etched without bending or defects, it was recorded as "excellent"; when the line or groove with a width between 3 and 10 μm could be clearly etched without bending or defects, it was recorded as "good"; when the line or groove with a width above 10 μm (excluding 10 μm) could be clearly etched without bending or defects, it was recorded as "poor".

[0105] 2) Evaluation of sensitivity: Using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited), different positive polyimide photosensitive resin compositions obtained were coated on a glass substrate by spin coating and pre-baked at 120 °C for 2 minutes. Exposure was carried out using an i-line stepper. After exposure, it was developed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 s, then washed with pure water, spin-dried, and the minimum exposure amount when the exposed part was completely dissolved was taken as the sensitivity.

[0106] 3) Residual film ratio: Using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited), different positive polyimide photosensitive resin compositions obtained were coated on a glass substrate by spin coating and pre-baked at 120 °C for 2 minutes. The thickness of the obtained film was denoted as d1. Then, the film was exposed, developed, and heat-treated to obtain a cured film, and its thickness was denoted as d2. The residual film ratio was calculated, and the calculation method of the residual film ratio was: (d2 / d1) * 100%. Among them, the thickness of the film was measured using a D600 type step gauge manufactured by KLA Corporation of the United States.

[0107] 4) Transmittance evaluation: Using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited), the obtained different positive polyimide photosensitive resin compositions were coated on a glass substrate by spin coating, pre-baked at 120 °C for 2 minutes, and then exposed, developed, and heat-treated to obtain a cured film. A spectrophotometer ("Double Beam Spectrophotometer U 2900" of Hitachi, Ltd.) was used to measure and evaluate the wavelength of the cured film from 300 nm to 800 nm. According to the measurement results, the transmittance at a wavelength of 400 nm was read as the basis for evaluating visible light transmittance. This is because, generally speaking, as long as there is no special record, the transmittance at 400 nm is the lowest, and in the region above 401 nm and less than 800 nm, the transmittance at 400 nm can represent the transmittance of the entire visible light region.

[0108] 5) Yellow index value measurement: Using a coating and developing apparatus ACT-8 (manufactured by Tokyo Electron Limited), the obtained different positive polyimide photosensitive resin compositions were coated on a glass substrate by spin coating, pre-baked at 120 °C for 2 minutes, and the obtained film was measured for the yellow index value using the Yellowness Index ASTM E313-2015 test standard. The yellow index value test equipment was the CM-36dG spectral tester of KONICA MINILTA.

[0109] See Table 4 for the above test results.

[0110] Table 4

[0111]

[0112]

[0113] The results in Table 4 show that by adding the photosensitizer composition developed in the present invention to the positive polyimide photosensitive resin composition, the yellowing problem can be significantly improved, and the effect is significantly better than that of adding TPPA-PAC (CAS No.: 137902-98-8), reaching a level comparable to that of adding Compound A (i.e., Comparative Example 9). Compared with Comparative Example 9, the samples prepared in the present invention are also comprehensively superior to the samples of Comparative Example 9 in terms of sensitivity, residual film rate, and transmittance, indicating that the positive polyimide photosensitive resin composition developed in the present invention can improve the film transmittance while maintaining its lithographic sensitivity and the cured residual film rate after lithography.

[0114] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, based on the above description, other different forms of changes or modifications can be made. It is impossible to enumerate all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A photosensitizer, characterized in that, The general structural formula of the photosensitizer is shown in Formula I; In Formula I, R1, R2, and R3 each independently represent a divalent organic group having 1 to 10 carbon atoms; D represents H or a group shown in Formula II, and at least one D represents a group shown in Formula II.

2. The photosensitizer according to claim 1, wherein The R1, R2, and R3 each independently represent a divalent organic group having 1 to 3 carbon atoms; Preferably, the R1, R2, and R3 each independently represent an alkylene group having 1 to 3 carbon atoms; Preferably, the R1, R2, and R3 represent the same group.

3. The photosensitizer according to claim 1, characterized in that, The D represents a group shown in Formula II.

4. The photosensitizer according to claim 1, wherein The photosensitizer is selected from one of the structures shown in Formulae I1 to I12 below:

5. A highly transparent positive polyimide photosensitive resin composition, characterized in that, By weight parts, the polyimide photosensitive resin composition comprises 10 - 35 parts of a photosensitizer composition; 95 - 105 parts of a polyimide-based resin; 15 - 25 parts of a crosslinking agent; 0.5 - 5 parts of a leveling agent; 0.1 - 2 parts of an adhesive; Wherein, the photosensitizer composition includes at least two photosensitizers according to any one of claims 1 - 4.

6. The polyimide photosensitive resin composition according to claim 5, wherein The solid content of the polyimide photosensitive resin composition is 8% - 20%.

7. The polyimide photosensitive resin composition according to claim 5, wherein In the photosensitizer composition, the molar ratio of the group of Formula II to H is 1:1 - 5:

1.

8. The polyimide photosensitive resin composition according to claim 5, wherein The photosensitizer composition is prepared according to the following steps: Under a nitrogen atmosphere, dissolve the compound of Formula I-1 and 5-naphthoquinone diazide sulfonyl chloride in an organic solvent, and dropwise add an organic solvent in which triethylamine is dispersed thereto at room temperature, controlling the temperature in the reaction system during the dropping process not to exceed 35°C. After the dropping is completed, stir and react at room temperature for 1.5 - 2.5 h, filter, pour the filtrate into water, then filter out the precipitate, and dry the precipitate to obtain it; Wherein, the compound of Formula I-1 is selected from the structures shown below: R1, R2, and R3 each independently represent a divalent organic group having 1 to 10 carbon atoms.

9. The polyimide photosensitive resin composition according to claim 8, wherein, The molar ratio of the compound of Formula I-1 to 5-naphthoquinone diazide sulfonyl chloride is 1:1.5 - 1:7; The addition amount of triethylamine and the molar ratio of 5-naphthoquinone diazide sulfonyl chloride is 1:

1.

10. The positive polyimide photosensitive resin composition according to claim 5, wherein The polyimide-based resin is selected from one or more of polyimide, polyimide precursor, polyamide-imide, polyamide-imide precursor, and polyetherimide; The crosslinking agent is selected from one or more of a compound having a benzoxazine structure, a compound having an epoxy structure, a compound having an oxetane structure, and a compound having an alkoxymethyl group; The leveling agent is selected from one or more of a surfactant, an ester, an alcohol, a ketone, and an ether; The adhesive is selected from one or more of aminopropyltrimethoxysilane, trimethoxyepoxysilane, vinyltrimethoxysilane, and mercaptopropyltrimethoxysilane.

11. A photosensitive polyimide cured film, characterized in that, The photosensitive polyimide cured film is obtained by dissolving the positive polyimide photosensitive resin composition according to any one of claims 5 - 10 and coating it on a substrate, and then curing it.

12. Display device, characterized in that, Comprising the polyimide cured film according to claim 11.

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