Preparation method of blue color paste for color photoresist

Abstract

This invention relates to the field of photoresist materials technology, specifically to a method for preparing blue pigment paste for color photoresist. The method includes the following steps: Step 1. Raw material selection and weighing; Step 2. Raw material pretreatment and sieving; Step 3. Raw material dispersion and grinding; Step 4. Secondary mixing and grinding; Step 5. Blending and mixing treatment; Step 6. Multi-stage filtration and other treatments; Step 7. Verification and waste recycling treatment. This invention pioneers a composite adhesion-promoting resin system. Through the synergistic effect of the interface between inorganic nanoparticles and organic functional groups, it breaks through the bottleneck of the bonding strength between traditional pigment pastes and substrates. Systematic comparative verification shows that this technology significantly improves the edge clarity of pixel patterns and the adhesion to the substrate, laying a key foundation for high-precision photolithography processes. The innovative design of multi-stage filtration and vacuum settling processes, combined with a waste recycling system, maximizes the utilization rate of raw materials.

Description

Technical Field

[0001] This invention relates to the field of photoresist materials technology, specifically to a method for preparing blue pigment paste for color photoresist. Background Technology

[0002] Photoresist is a crucial functional material that uses photochemical reactions and processes such as exposure and development to precisely transfer patterns from a photomask to a substrate. In liquid crystal display (LCD) manufacturing, color photoresist is used to prepare color filters, which achieve rich color display through an array of red (R), green (G), and blue (B) primary color pixels. Blue pigment, as the core component for coloring blue photoresist, primarily provides the photoresist with the required blue hue, hiding power, and optical properties. The performance of blue pigment, such as dispersion stability, tinting strength, thermal stability, and contrast ratio, directly determines the final display's color saturation, color gamut, brightness, and image quality.

[0003] In existing technologies, the preparation of blue pigment paste is usually based on organic pigments such as phthalocyanine blue. For example, Chinese patent application number CN202210902758.9, authorized on September 13, 2024, discloses a method for preparing blue pigment paste for color photoresist. The method includes: S1, preparation of synthetic resin: obtaining synthetic resin by random copolymerization of raw materials of synthetic resin using a polymer polymerization reaction method; S2, kneading treatment: adding blue pigment, ethylene glycol, sodium chloride, synthetic resin, dispersant and ethylenediaminetetraacetic acid into a kneader for kneading treatment, followed by washing and drying; S3, preparation of pigment paste: weighing the kneaded blue pigment, acrylic resin, dispersant and solvent according to the ratio, adding zirconium balls, and dispersing in a shaker to obtain a blue dispersion. The patent states that by attaching resin or dispersant to the surface of the blue pigment, the attraction of the pigment itself is minimized, thus solving the problem of difficult dispersion of blue pigment, making the blue pigment paste less prone to agglomeration and stratification, and improving the stability of the pigment paste; at the same time, by adding synthetic resin for kneading treatment, the chroma and contrast of the modified dye can be further improved.

[0004] However, the existing technology and its preparation method for blue pigments in color photoresists still have the following prominent drawbacks and limitations in industrial practice: The dispersion stability is still insufficient: Despite surface modification, phthalocyanine blue pigment is still prone to aggregation and sedimentation during storage due to its non-polar molecular structure and high specific surface area. This results in poor batch consistency of the pigment paste and often requires redispersion before use, affecting production efficiency and high-precision coating effect.

[0005] Thermal stability needs improvement: In the manufacturing process of color filters, a post-baking process at temperatures as high as 230°C or even higher is required. Organic components in existing color pastes (such as certain dispersants or insufficiently coated pigments) are prone to thermal decomposition or sublimation at high temperatures, producing "sublimated foreign matter" that contaminates adjacent pixels and significantly reduces product yield.

[0006] Bottlenecks exist in key optical performance: Blue pigments prepared by existing methods still cannot fully meet the growing demands of high-end display panels (such as 4K / 8K) in terms of key optical indicators such as contrast ratio, brightness (Y value) and color gamut coverage (NTSC), and there is room for improvement in color performance and image purity.

[0007] The preparation process is complex and costly: existing methods typically involve multi-step synthesis and lengthy physical processing (such as kneading and grinding for tens of hours), resulting in high energy consumption, low efficiency, and long production cycles. In addition, core raw materials (such as high-performance dispersants and specific resin monomers) are mostly imported, which further increases production costs and restricts its large-scale industrial application and market competitiveness.

[0008] Therefore, there is an urgent need in the field to develop a method for preparing blue pigment paste for color photoresists that can effectively solve the above problems, has high dispersion stability, excellent thermal stability, and superior optical performance, and has a simpler process and optimized cost. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing blue pigment for color photoresist, so as to overcome the above-mentioned shortcomings in the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing blue pigment paste for color photoresist, step 1. Raw material selection and weighing: Select blue pigment, synthetic resin, dispersant, solvent and additives as the main raw materials, and weigh each raw material according to the weight parts, wherein the weight ratio of blue pigment to synthetic resin ensures the coloring power and adhesion of the pigment paste; It should be noted that: In step one: The blue pigment is phthalocyanine blue PB15:6 or phthalocyanine blue PB15:3, with a specific surface area of ​​40-60 m² / g and a purity of ≥98%. The synthetic resin is an alkali-soluble acrylic resin or a maleimide-acrylate copolymer. The maleimide-acrylate copolymer is prepared by polymerizing maleimide monomers, acrylate monomers and carboxyl-containing monomers in a mass ratio of (5-15):(30-50):(20-40) at 60-90°C for 4-10 hours, and the acid value is controlled to be 80-150 mgKOH / g. The dispersant is a polyurethane dispersant or an anionic wetting agent; The solvent is propylene glycol methyl ether acetate or cyclohexanone; The additives include defoamers and leveling agents; The raw materials are weighed in the following proportions by weight: 15-25 parts blue pigment, 10-20 parts synthetic resin, 3-8 parts dispersant, 45-65 parts solvent, and 0.5-2 parts additive.

[0011] In step one, a silane coupling agent is also weighed for pigment surface modification, with a mass ratio of 5-15:100 to the blue pigment. The silane coupling agent is a mixture of vinyltriethoxysilane and tetraethyl orthosilicate in a molar ratio of 3:1. In step one, a high-molecular-weight red dye is also weighed for color enhancement, with a mass ratio of 0.5-2:100 to the blue pigment. In step one, 0.3-0.5 parts of fluorescence quencher multi-walled carbon nanotubes are also weighed to suppress the fluorescence effect.

[0012] Step 2. Raw material pretreatment and sieving: Surface modification treatment is performed on the blue pigment, synthetic resin is prepared, the required acid value is obtained through polymerization reaction, and the solid raw materials are sieved to remove large particle size impurities to ensure the uniformity of the raw materials. Solvents and additives are pre-filtered. It should be noted that: In step two: The specific process for surface modification of the blue pigment is as follows: blue pigment, silane coupling agent, dispersant and part of solvent are mixed at a mass ratio of 100:(5-15):(5-15):(50-100), and kneaded in a kneader at 45-60℃ and 30-50rpm for 35-45 hours to form a polysiloxane coating layer; then washed with deionized water until the conductivity is ≤50 μS / cm, filtered and vacuum dried at 75-85℃ for 10-15 hours to obtain the surface-modified blue pigment; The sieving process for solid raw materials involves using a 100-200 mesh standard sieve to remove impurities with a particle size greater than 100 μm.

[0013] Step 3. Raw material dispersion and grinding: The surface-modified blue pigment, synthetic resin, dispersant and part of the solvent are mixed to form a pre-dispersed slurry, and a multi-stage grinding process is used for preliminary dispersion. Zirconia beads are used as the grinding medium to control the slurry particle size to the nanoscale range. The viscosity and temperature of the slurry are monitored during the grinding process to ensure dispersion stability. It should be noted that: In step three: The solvent in question accounts for 50-70% of the total solvent mass; In the multi-stage grinding process, 0.3 mm zirconia beads are first used as the grinding media, and grinding is carried out at 25-40℃ and 1500-3000 rpm for 5-15 hours, controlling the slurry particle size D50≤100 nm and D90≤150 nm. The viscosity of the slurry is monitored in real time during the grinding process to ensure that the viscosity is controlled within the range of 1000-1500 cP, and a circulating water cooling system is used for temperature control.

[0014] Step 4. Secondary mixing and grinding: Add the remaining solvent and additives to the initially dispersed slurry, and use a fine grinding process with smaller zirconia beads to further control the slurry particle size to a narrower nanoscale distribution. High-pressure homogenization is also used to help narrow the particle size distribution. It should be noted that: In step four: The fine grinding process uses 0.1 mm zirconia beads as the grinding media and continues grinding for 5-12 hours at 25-40℃ and 2000-3500 rpm until the slurry particle size D50≤80 nm and D90≤120 nm. The high-pressure homogenization is performed by using a high-pressure microfluidic homogenizer at a pressure of 15,000-25,000 psi for 1-3 times, with 0.3-0.5 parts of multi-walled carbon nanotubes added as a fluorescence quencher.

[0015] Step 5. Blending and mixing: Add color enhancer and stabilizing agent to the ground slurry, and mix it under light-protected conditions. Adjust the viscosity and solid content of the slurry to the target range, and add solvent or photoinitiator during the blending and mixing process to enhance performance. It should be noted that: In step five: The color enhancer is a high molecular weight red dye with a mass ratio of 0.5-2:100 to blue pigment. The dye is prepared by condensing Acid Red 52 with 2,4,6-tristyrylphenol polyoxyethylene ether after acidification and acyl chloride treatment. The stabilizing agent is pH adjuster AMP-95, used to adjust the pH of the slurry to 7.5-8.5; the target range is a viscosity of 40-50 mPa·s (at 25℃) and a solid content of 15-25%; the photoinitiator is Irgacure 907, added in an amount of 2-5 parts.

[0016] Step 6. Multi-stage filtration and other treatments: The slurry is filtered through multiple filter cartridges in sequence to remove agglomerated particles and mechanical impurities, ensuring the fineness of the slurry. Subsequently, vacuum settling is performed to remove microbubbles and improve the uniformity of the slurry. Finally, the filter residue is collected. It should be noted that: In step six: The multi-stage filtration is performed by sequentially passing through 1.0 μm and 0.5 μm polytetrafluoroethylene filter elements; The vacuum settling process involves setting the vessel at a vacuum of -0.08 MPa to -0.1 MPa for 20-60 minutes, accompanied by low-speed stirring at 30-60 rpm. The filtration pressure is controlled at 0.1-0.3 MPa to ensure that the final slurry fineness is ≤0.15 μm.

[0017] Step 7. Validation and Waste Recycling: The final blue pigment is validated for performance, including particle size distribution, thermal stability, contrast, storage stability and color gamut coverage. Waste and filter residue are then recycled. Batch records are established to ensure process traceability. Non-conforming products are reprocessed. It should be noted that: In step seven: The specific performance verification indicators include: particle size distribution D50≤80 nm, D90≤120 nm, thermal stability after 230℃ / 1 h color difference ΔE<1.5, contrast ratio ≥12000, storage stability after 30 days particle size growth rate <5%, and color gamut coverage ≥85% NTSC standard. The recycling of waste materials and filter residues includes: distillation and purification of washing solvents for reuse, and centrifugation separation of solid residues, with a proportion not exceeding 10% of the new material used for the production of low-grade color pastes.

[0018] The reprocessing of the defective products involves adding 0.5% of the original total amount of dispersant and then returning to step three for re-dispersion and grinding.

[0019] In the above technical solution, the method for preparing blue pigment for color photoresist provided by the present invention has the following beneficial effects: (1) This invention is the first to create a composite adhesion-promoting resin system. Through the synergistic effect of the interface between inorganic nanoparticles and organic functional groups, it breaks through the bottleneck of the bonding strength between traditional pigments and substrates. After systematic comparative verification, this technology significantly improves the edge clarity of pixel patterns and the bonding force with the substrate, laying a key foundation for high-precision photolithography.

[0020] (2) This invention achieves a uniform dispersion system with nanoscale particle size by combining surface modification treatment of blue pigment with multi-stage grinding process. The synergistic effect of zirconium oxide bead grinding and high pressure homogenization, combined with dispersant and stabilizing agent, forms a narrow distribution of particles, which significantly inhibits agglomeration and sedimentation. After long-term storage verification, the system maintains high stability and excellent batch consistency, effectively eliminating the need for re-dispersion before use, and providing a reliable guarantee for industrial production.

[0021] (3) Based on a synthetic resin system with a specific acid value range, this invention combines inorganic-organic synergistic modification technology to significantly improve the tolerance of color paste in high-temperature post-baking process. By introducing carbon-based fluorescent quenching materials, the thermal decomposition chain reaction is effectively blocked, and the color stability can still be maintained under harsh process conditions, greatly reducing the risk of sublimation contamination of adjacent pixels.

[0022] (4) This invention relies on the dual optimization of polymer color enhancer and precision grinding process to make the color paste present a high-purity blue tone and excellent light transmission characteristics. By adjusting the resin refractive index and dye ratio, the contrast and color gamut coverage of the display panel are significantly improved, meeting the stringent requirements of ultra-high-definition display technology for image purity and color level.

[0023] (5) This invention innovatively designs a multi-stage filtration and vacuum settling process, combined with a waste recycling system, to maximize the utilization rate of raw materials. Through the optimization of grinding parameters and the strategy of replacing domestic raw materials, energy consumption and import dependence are effectively reduced while ensuring performance. The process route is both environmentally friendly and economical, providing a sustainable solution for large-scale production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0025] Figure 1 This is a flowchart illustrating an embodiment of the preparation method of blue pigment for color photoresist according to the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] like Figure 1 As shown in the embodiment of the present invention, a method for preparing blue pigment paste for color photoresist is provided. Step 1. Raw material selection and weighing: Select blue pigment, synthetic resin, dispersant, solvent and additives as main raw materials, and weigh each raw material according to the weight parts. The weight ratio of blue pigment to synthetic resin ensures the coloring power and adhesion of the pigment paste. It should be noted that: In step one: The blue pigment is Phthalocyanine Blue PB15:6 or Phthalocyanine Blue PB15:3, with a specific surface area of ​​40-60 m² / g and a purity of ≥98%. The synthetic resin is an alkali-soluble acrylic resin or a maleimide-acrylate copolymer. The maleimide-acrylate copolymer is prepared by polymerizing maleimide monomers, acrylate monomers and carboxyl-containing monomers in a mass ratio of (5-15):(30-50):(20-40) at 60-90℃ for 4-10 hours, and the acid value is controlled to be 80-150 mgKOH / g. The dispersant is a polyurethane dispersant or an anionic wetting agent; The solvent is propylene glycol methyl ether acetate or cyclohexanone; Additives include defoamers and leveling agents; The raw materials are weighed in the following proportions by weight: 15-25 parts blue pigment, 10-20 parts synthetic resin, 3-8 parts dispersant, 45-65 parts solvent, and 0.5-2 parts additive.

[0028] In step one, a silane coupling agent is also weighed for pigment surface modification. Its mass ratio with the blue pigment is 5-15:100. The silane coupling agent is a mixture of vinyltriethoxysilane and tetraethyl orthosilicate in a molar ratio of 3:1. In step one, a high-molecular-weight red dye is also weighed for color enhancement, with a mass ratio of 0.5-2:100 to the blue pigment. In step one, 0.3-0.5 parts of multi-walled carbon nanotubes, a fluorescence quencher, are also weighed to suppress the fluorescence effect.

[0029] Step 2. Raw material pretreatment and sieving: Surface modification treatment is performed on the blue pigment, synthetic resin is prepared, the required acid value is obtained through polymerization reaction, and the solid raw materials are sieved to remove large particle size impurities to ensure the uniformity of the raw materials. Solvents and additives are pre-filtered. It should be noted that: In step two: The specific process for surface modification of blue pigment is as follows: blue pigment, silane coupling agent, dispersant and part of solvent are mixed at a mass ratio of 100:(5-15):(5-15):(50-100), and kneaded in a kneader at 45-60℃ and 30-50 rpm for 35-45 hours to form a polysiloxane coating layer; then washed with deionized water until the conductivity is ≤50 μS / cm, filtered and vacuum dried at 75-85℃ for 10-15 hours to obtain surface-modified blue pigment; Sieving solid raw materials involves using a 100-200 mesh standard sieve to remove impurities with a particle size greater than 100 μm.

[0030] Step 3. Raw material dispersion and grinding: The surface-modified blue pigment, synthetic resin, dispersant and part of the solvent are mixed to form a pre-dispersed slurry, and a multi-stage grinding process is used for preliminary dispersion. Zirconia beads are used as the grinding medium to control the slurry particle size to the nanoscale range. The viscosity and temperature of the slurry are monitored during the grinding process to ensure dispersion stability. It should be noted that: In step three: Some solvents account for 50-70% of the total solvent mass; In the multi-stage grinding process, 0.3 mm zirconia beads are first used as grinding media, and grinding is carried out at 25-40℃ and 1500-3000 rpm for 5-15 hours, controlling the slurry particle size D50≤100 nm and D90≤150 nm. The viscosity of the slurry is monitored in real time during the grinding process to ensure that the viscosity is controlled within the range of 1000-1500 cP, and a circulating water cooling system is used for temperature control.

[0031] Step 4. Secondary mixing and grinding: Add the remaining solvent and additives to the initially dispersed slurry, and use a fine grinding process with smaller zirconia beads to further control the slurry particle size to a narrower nanoscale distribution. High-pressure homogenization is also used to help narrow the particle size distribution. It should be noted that: In step four: The fine grinding process uses 0.1 mm zirconia beads as the grinding media and continues grinding for 5-12 hours at 25-40℃ and 2000-3500 rpm until the slurry particle size D50≤80 nm and D90≤120 nm. High-pressure homogenization involves using a high-pressure microfluidic homogenizer to perform assisted homogenization 1-3 times at a pressure of 15000-25000 psi, with 0.3-0.5 parts of multi-walled carbon nanotubes added as a fluorescence quencher.

[0032] Step 5. Blending and mixing: Add color enhancer and stabilizing agent to the ground slurry, and mix it under light-protected conditions. Adjust the viscosity and solid content of the slurry to the target range, and add solvent or photoinitiator during the blending and mixing process to enhance performance. It should be noted that: In step five: The color enhancer is a high molecular weight red dye with a mass ratio of 0.5-2:100 to the blue pigment. This dye is prepared by condensing Acid Red 52 with 2,4,6-tristyrylphenol polyoxyethylene ether after acidification and acyl chloride treatment. The stabilizing agent is pH adjuster AMP-95, used to adjust the pH of the slurry to 7.5-8.5; the target range is viscosity of 40-50 mPa·s (at 25℃) and solid content of 15-25%; the photoinitiator is Irgacure 907, added at a rate of 2-5 parts.

[0033] Step 6. Multi-stage filtration and other treatments: The slurry is filtered through multiple filter cartridges in sequence to remove agglomerated particles and mechanical impurities, ensuring the fineness of the slurry. Subsequently, vacuum settling is performed to remove microbubbles and improve the uniformity of the slurry. Finally, the filter residue is collected. It should be noted that: In step six: Multi-stage filtration involves sequentially passing the material through 1.0 μm and 0.5 μm polytetrafluoroethylene filter elements; The vacuum settling process involves setting the vessel under a vacuum of -0.08 MPa to -0.1 MPa for 20-60 minutes, while simultaneously stirring at a low speed of 30-60 rpm. The filtration pressure is controlled at 0.1-0.3 MPa to ensure that the final slurry fineness is ≤0.15 μm.

[0034] Step 7. Validation and Waste Recycling: The final blue pigment is validated for performance, including particle size distribution, thermal stability, contrast, storage stability and color gamut coverage. Waste and filter residue are then recycled. Batch records are established to ensure process traceability. Non-conforming products are reprocessed. It should be noted that: In step seven: The specific performance verification indicators include: particle size distribution D50≤80 nm, D90≤120 nm, thermal stability after 230℃ / 1 h color difference ΔE<1.5, contrast ratio ≥12000, storage stability after 30 days particle size growth rate <5%, and color gamut coverage ≥85% NTSC standard. The recycling of waste materials and filter residues includes: distillation and purification of washing solvents for reuse, and centrifugation of solid residues for use in the production of low-grade color pastes at a ratio not exceeding 10% of the new material.

[0035] For non-conforming products, reprocessing involves adding 0.5% of the original total amount of dispersant and returning to step three for re-dispersion and grinding.

[0036] Example 1 (Low Pigment Content Endpoint) Raw material ratio: Main ingredients: Phthalocyanine Blue PB15:6 (15 parts), Maleimide-acrylate copolymer (acid value 80 mgKOH / g, 10 parts), polyurethane dispersant BYK-190 (3 parts), propylene glycol methyl ether acetate (65 parts). Additives: Defoamer BYK-055 (0.5 parts), leveling agent BYK-361 (0.5 parts); Functional additives: silane coupling agent mixture (VTES:TEOS=3:1, 2.25 parts), multi-walled carbon nanotubes (0.3 parts), and high molecular weight red dye (0.225 parts). Key processes: Pretreatment: The blue pigment is kneaded with silane coupling agent, dispersant and 50 parts solvent (45℃, 30 rpm, 35 hours), washed and dried and then passed through a 100-mesh sieve; Primary grinding: The modified pigment was mixed with resin, dispersant and 32.5 parts solvent and ground with 0.3 mm zirconia beads for 5 hours (25℃, 1500 rpm), with viscosity controlled at 1000 cP; Fine grinding: Add the remaining solvent, replace with 0.1 mm zirconia beads and grind for 5 hours (2000 rpm), then homogenize once under high pressure of 15000 psi; Preparation: Add dye and AMP-95 to adjust pH to 7.5, adjust viscosity to 40 mPa·s, and add photoinitiator Irgacure907 (2 parts). Post-treatment: staged filtration through 1.0 μm→0.5 μm filter cartridges, followed by vacuum static degassing (-0.08 MPa, 20 minutes).

[0037] Performance results: Particle size: D50=78 nm, D90=118 nm; Thermal stability (230℃ / 1 h): ΔE=1.4; Optical performance: 12000 contrast ratio, 85% NTSC color gamut coverage; Storage stability: Particle size increased by 4.8% after 30 days, and no sediment was observed after centrifugation.

[0038] Example 2 (Intermediate Value) Raw material ratio: Main ingredients: Phthalocyanine Blue PB15:6 (20 parts), Maleimide-acrylate copolymer (acid value 120 mgKOH / g, 15 parts), polyurethane dispersant BYK-190 (5 parts), propylene glycol methyl ether acetate (55 parts). Additives: Defoamer BYK-055 (0.5 parts), leveling agent BYK-361 (0.5 parts); Functional additives: silane coupling agent mixture (VTES:TEOS=3:1, 3 parts), multi-walled carbon nanotubes (0.4 parts), high molecular weight red dye (0.3 parts); Key processes: Pretreatment: The blue pigment is kneaded with silane coupling agent, dispersant and 40 parts solvent (50℃, 40 rpm, 40 hours), washed and dried and then passed through a 150-mesh sieve; Primary grinding: The modified pigment is mixed with resin, dispersant and 35 parts solvent, and ground with 0.3 mm zirconia beads for 10 hours (30℃, 2000 rpm), with viscosity controlled at 1200 cP; Fine grinding: Add the remaining solvent, replace with 0.1 mm zirconia beads and grind for 8 hours (2500 rpm), then homogenize twice under high pressure at 20000 psi; Preparation: Add dye and AMP-95 to adjust pH to 8.0, adjust viscosity to 45 mPa·s, and add photoinitiator Irgacure907 (3 parts). Post-treatment: filtered through 1.0 μm → 0.5 μm filter cartridges, followed by vacuum static degassing (-0.09 MPa, 40 minutes).

[0039] Performance results: Particle size: D50=75 nm, D90=115 nm; Thermal stability (230℃ / 1 h): ΔE=1.2; Optical performance: 12500 contrast ratio, 86% NTSC color gamut coverage; Storage stability: Particle size increased by 3.8% after 30 days, and no sediment was observed after centrifugation.

[0040] Example 3 (High Pigment Content Endpoint) Raw material ratio: Main ingredients: Phthalocyanine Blue PB15:3 (25 parts), Alkali-soluble acrylic resin (acid value 150 mgKOH / g, 20 parts), Anionic wetting agent DISPERBYK-102 (8 parts), Cyclohexanone (45 parts). Additives: Defoamer BYK-055 (1 part), leveling agent BYK-361 (1 part); Functional additives: silane coupling agent mixture (VTES:TEOS=3:1, 3.75 parts), multi-walled carbon nanotubes (0.5 parts), and high molecular weight red dye (0.5 parts). Key processes: Pretreatment: The blue pigment was kneaded with silane coupling agent, dispersant and 45 parts solvent (60℃, 50 rpm, 45 hours), washed and dried and then passed through a 200-mesh sieve; Primary grinding: The modified pigment was mixed with resin, dispersant and 31.5 parts solvent and ground with 0.3 mm zirconia beads for 15 hours (40℃, 3000 rpm), with viscosity controlled at 1500 cP; Fine grinding: Add the remaining solvent, replace with 0.1 mm zirconia beads and grind for 12 hours (3500 rpm), then homogenize three times under high pressure at 25000psi; Preparation: Add dye and AMP-95 to adjust pH to 8.5, adjust viscosity to 50 mPa·s, and add photoinitiator Irgacure907 (5 parts). Post-treatment: staged filtration through 1.0 μm → 0.5 μm filter cartridges, followed by vacuum static degassing (-0.1 MPa, 60 minutes).

[0041] Performance results: Particle size: D50=72 nm, D90=110 nm; Thermal stability (230℃ / 1 h): ΔE=1.0; Optical performance: 12800 contrast ratio, 87% NTSC color gamut coverage; Storage stability: Particle size increased by 3.5% after 30 days, and no sediment was observed after centrifugation.

[0042] Comparative example (traditional method) Referring to the solution in patent CN115202150B: No pigment surface modification was performed; Single grinding for 15 hours (no multi-stage process); No high-pressure homogenization or carbon nanotube addition.

[0043] Performance defects Particle size: D50=150 nm, D90=185 nm; Thermal stability: ΔE = 3.8; Optical performance: 8000 contrast ratio, 70% NTSC color gamut coverage; Significant sedimentation occurred after 7 days of storage, and the particle size increased by 16.5% after 30 days. Performance Comparison Summary Table in conclusion: This invention fully verifies the effectiveness and stability of the technical solution across the entire parameter range by setting three examples representing the endpoints and intermediate values ​​of the formulation range. Examples 1-3 form a gradient comparison in terms of key raw material ratios (15-25 parts blue pigment, 10-20 parts resin, and 3-8 parts dispersant) and process conditions. The results show that the synergistic effect of silane coupling agent surface modification, multi-stage grinding, and high-pressure homogenization significantly improves the dispersibility and thermal stability of the pigment paste; the introduction of the composite resin system and fluorescence quencher further optimizes the optical performance. Compared with traditional processes, the pigment paste prepared by this invention has a narrower particle size distribution by more than 50%, a 67%-74% reduction in thermal stability color difference, and an increase in color gamut coverage of over 20%. Furthermore, it exhibits excellent storage stability at all different ratio endpoints, fully verifying the wide applicability and innovative advantages of the technical solution.

[0044] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for preparing blue pigment for color photoresist, characterized in that, Includes the following steps: Step 1. Raw material selection and weighing: Select blue pigment, synthetic resin, dispersant, solvent and additives as the main raw materials, and weigh each raw material according to the weight parts. The weight ratio of blue pigment to synthetic resin ensures the coloring power and adhesion of the color paste. Step 2. Raw material pretreatment and sieving: Surface modification treatment is performed on the blue pigment, synthetic resin is prepared, the required acid value is obtained through polymerization reaction, and the solid raw materials are sieved to remove large particle size impurities to ensure the uniformity of the raw materials. Solvents and additives are pre-filtered. Step 3. Raw material dispersion and grinding: The surface-modified blue pigment, synthetic resin, dispersant and part of the solvent are mixed to form a pre-dispersed slurry, and a multi-stage grinding process is used for preliminary dispersion. Zirconia beads are used as the grinding medium to control the slurry particle size to the nanoscale range. The viscosity and temperature of the slurry are monitored during the grinding process to ensure dispersion stability. Step 4. Secondary mixing and grinding: Add the remaining solvent and additives to the initially dispersed slurry, and use a fine grinding process with smaller zirconia beads to further control the slurry particle size to a narrower nanoscale distribution. High-pressure homogenization is also used to help narrow the particle size distribution. Step 5. Blending and mixing: Add color enhancer and stabilizing agent to the ground slurry, and mix it under light-protected conditions. Adjust the viscosity and solid content of the slurry to the target range, and add solvent or photoinitiator during the blending and mixing process to enhance performance. Step 6. Multi-stage filtration and other treatments: The slurry is filtered through multiple filter cartridges in sequence to remove agglomerated particles and mechanical impurities, ensuring the fineness of the slurry. Subsequently, vacuum settling is performed to remove microbubbles and improve the uniformity of the slurry. Finally, the filter residue is collected. Step 7. Validation and Waste Recycling: The final blue pigment is validated for performance, including particle size distribution, thermal stability, contrast, storage stability and color gamut coverage. Waste and filter residue are then recycled. Batch records are established to ensure process traceability, and non-conforming products are reprocessed.

2. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step one: The blue pigment is phthalocyanine blue PB15:6 or phthalocyanine blue PB15:3, with a specific surface area of ​​40-60 m² / g and a purity of ≥98%. The synthetic resin is an alkali-soluble acrylic resin or a maleimide-acrylate copolymer. The maleimide-acrylate copolymer is prepared by polymerizing maleimide monomers, acrylate monomers and carboxyl-containing monomers in a mass ratio of (5-15):(30-50):(20-40) at 60-90°C for 4-10 hours, and the acid value is controlled to be 80-150 mgKOH / g. The dispersant is a polyurethane dispersant or an anionic wetting agent; The solvent is propylene glycol methyl ether acetate or cyclohexanone; The additives include defoamers and leveling agents; The raw materials are weighed in the following proportions by weight: 15-25 parts blue pigment, 10-20 parts synthetic resin, 3-8 parts dispersant, 45-65 parts solvent, and 0.5-2 parts additive.

3. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step one, a silane coupling agent is also weighed for pigment surface modification, with a mass ratio of 5-15:100 to the blue pigment. The silane coupling agent is a mixture of vinyltriethoxysilane and tetraethyl orthosilicate in a molar ratio of 3:

1. In step one, a high-molecular-weight red dye is also weighed for color enhancement, with a mass ratio of 0.5-2:100 to the blue pigment. In step one, 0.3-0.5 parts of fluorescence quencher multi-walled carbon nanotubes are also weighed to suppress the fluorescence effect.

4. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step two: The specific process for surface modification of the blue pigment is as follows: Blue pigment, silane coupling agent, dispersant, and a portion of solvent are mixed at a mass ratio of 100:(5-15):(5-15):(50-100), and kneaded in a kneader at 45-60℃ and 30-50 rpm for 35-45 hours to form a polysiloxane coating layer; subsequently, it is washed with deionized water until the conductivity is ≤50 μS / cm, filtered, and vacuum dried at 75-85℃ for 10-15 hours to obtain the surface-modified blue pigment. The sieving process for the solid raw materials involves using a 100-200 mesh standard sieve to remove impurities with a particle size greater than 100 μm.

5. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step three: The solvent in question accounts for 50-70% of the total solvent mass; In the multi-stage grinding process, 0.3 mm zirconia beads are first used as the grinding media, and grinding is carried out at 25-40℃ and 1500-3000 rpm for 5-15 hours, controlling the slurry particle size D50≤100 nm and D90≤150 nm. The viscosity of the slurry is monitored in real time during the grinding process to ensure that the viscosity is controlled within the range of 1000-1500 cP, and a circulating water cooling system is used for temperature control.

6. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step four: The fine grinding process uses 0.1 mm zirconia beads as the grinding media and continues grinding for 5-12 hours at 25-40℃ and 2000-3500 rpm until the slurry particle size D50≤80 nm and D90≤120 nm. The high-pressure homogenization is performed by using a high-pressure microfluidic homogenizer at a pressure of 15,000-25,000 psi for 1-3 times, with 0.3-0.5 parts of multi-walled carbon nanotubes added as a fluorescence quencher.

7. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step five: The color enhancer is a high molecular weight red dye with a mass ratio of 0.5-2:100 to blue pigment. The dye is prepared by condensing Acid Red 52 with 2,4,6-tristyrylphenol polyoxyethylene ether after acidification and acyl chloride treatment. The stabilizing agent is pH adjuster AMP-95, used to adjust the pH of the slurry to 7.5-8.5; the target range is a viscosity of 40-50 mPa·s and a solid content of 15-25%; the photoinitiator is Irgacure 907, added in an amount of 2-5 parts.

8. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step six: The multi-stage filtration is performed by sequentially passing through 1.0 μm and 0.5 μm polytetrafluoroethylene filter elements; The vacuum settling process involves setting the vessel at a vacuum of -0.08 MPa to -0.1 MPa for 20-60 minutes, accompanied by low-speed stirring at 30-60 rpm. The filtration pressure is controlled at 0.1-0.3 MPa to ensure that the final slurry fineness is ≤0.15 μm.

9. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step seven: The specific performance verification indicators include: particle size distribution D50≤80 nm, D90≤120 nm, thermal stability after 230℃ / 1 h color difference ΔE<1.5, contrast ratio ≥12000, storage stability after 30 days particle size growth rate <5%, and color gamut coverage ≥85% NTSC standard. The recycling of waste materials and filter residues includes: distillation and purification of washing solvents for reuse, and centrifugation separation of solid residues, with a proportion not exceeding 10% of the new material used for the production of low-grade color pastes.

10. The method for preparing blue pigment for color photoresist according to claim 1, characterized in that, In step seven: The reprocessing of the defective products involves adding 0.5% of the original total amount of dispersant and then returning to step three for re-dispersion and grinding.

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