Formula of high-blackness ink for LED display packaging and organic silicon modified resin gradient dispersion process

Abstract

The invention relates to the technical field of ink preparation, in particular to a high-blackness ink formula for LED display packaging and an organic silicon modified resin gradient dispersion process. The high-blackness ink formula is prepared from, by mass, 8-20 parts of high-blackness composite pigment, 30-50 parts of organic silicon modified resin, 2-8 parts of polymeric dispersant, 1-5 parts of functional additive and 15-35 parts of high-purity solvent. The organic silicon modified resin provides excellent high and low temperature resistance and yellowing resistance, the unique molecular structure of the organic silicon modified resin is more beneficial to wetting and coating of pigment particles, the three-stage gradient dispersion process is matched with online monitoring, and through stepped increase of the rotating speed and the temperature and ultrasonic assistance, the high-temperature-resistant and anti-yellowing performance of the pigment is improved. Progressive dispersion of the pigment from preliminary wetting to deep coating is realized, and nanoscale uniform distribution and long-term stability of the pigment in resin are ensured. The finally prepared ink has the comprehensive advantages of high blackness, low light transmittance, strong adhesive force, wide process window and the like, and perfectly meets the packaging requirements of high-end LED display.

Description

Technical Field

[0001] This invention relates to the field of ink preparation technology, and in particular to a high-blackness ink formulation for LED display packaging and a gradient dispersion process for silicone-modified resin. Background Technology

[0002] In the packaging process of LED display devices (especially Mini / MicroLEDs), high-blackness inks are crucial for achieving optical isolation between pixels, preventing light crosstalk, and improving contrast. Traditional packaging inks often use carbon black as a single pigment, which suffers from insufficient blackness (L* value) and limited blocking rate for visible light (especially blue light emitted by LED chips). Furthermore, carbon black particles have a large specific surface area and high surface energy, making them prone to agglomeration in organic resin systems, leading to uneven dispersion, poor ink stability, and the appearance of light-transmitting spots or uneven film layers after coating and curing. The temperature resistance, yellowing resistance, and flexibility of conventional resin matrices (such as epoxy resins) are also insufficient to meet the requirements of long-term operation of LED devices and subsequent reflow soldering processes. Therefore, developing a high-blackness ink that combines extreme blackness, excellent dispersion stability, good process adaptability, and reliable packaging performance has become a key technological bottleneck for improving LED display quality. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and to propose a high-blackness ink formulation and a gradient dispersion process for silicone-modified resin for LED display packaging.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-blackness ink formulation for LED display packaging and a gradient dispersion process for organosilicon modified resin, comprising, by mass parts, 8-20 parts of high-blackness composite pigment, 30-50 parts of organosilicon modified resin, 2-8 parts of polymeric dispersant, 1-5 parts of functional additives, and 15-35 parts of high-purity solvent. The process achieves gradient dispersion of silicone-modified resin by adjusting the dispersion speed and temperature in stages, so that pigment particles are uniformly coated on the resin matrix. After the ink is cured, a high blackness and low light transmittance encapsulation film layer is formed, which is suitable for the light-shielding encapsulation requirements of LED display devices.

[0005] Preferably, the high-blackness composite pigment is composed of carbon black and titanium black in a mass ratio of 3-5:1; the carbon black is furnace black with a particle size of 15-40 nm and a specific surface area of ​​80-150 m². 2 / g, oil absorption value 1.0-1.8mL / g; titanium black is Ti4O7 or Ti3O5, particle size 20-50nm, blackness L* value ≤15, visible light transmittance ≤0.5%.

[0006] Preferably, the organosilicon-modified resin uses epoxy resin or acrylic resin as the base material and is grafted and modified by silane coupling agents KH-560, KH-570 or KH-792; the modified resin has a silicon content of 3-8wt%, a viscosity of 1000-8000 mPa・s at 25℃, a solid content of 60%-80%, a glass transition temperature of 80-150℃, and a temperature resistance range of -40-200℃.

[0007] Preferably, the polymeric dispersant is a mixture of polyurethane dispersant and polyether dispersant in a mass ratio of 1-2:1; the polyurethane dispersant is selected from BYK-163 and EFKA-4046, and the polyether dispersant is selected from BYK-180 and TEGODispers750W; the total amount of dispersant is 10%-40% of the mass of the high-blackness composite pigment.

[0008] Preferably, the functional additive is a compound of defoamer, leveling agent and antioxidant in a mass ratio of 2-3:1-2:1; the defoamer is selected from organosilicon BYK-055 and polyether EFKA-2020, the leveling agent is selected from acrylate TEGOFlow370, and the antioxidant is selected from hindered phenol 1010 and phosphite 168; the high-purity solvent is selected from one or more of propylene glycol methyl ether acetate, butyl acetate and cyclohexanone, the solvent water content is ≤0.3%, the purity is ≥99.5%, and the evaporation rate at 25℃ is 0.3-0.8 times that of ethyl acetate.

[0009] Preferably, the high-blackness composite pigment undergoes surface modification treatment, with the modifier being a titanate coupling agent or an aluminate coupling agent, and the amount used is 1%-3% of the pigment mass; the water contact angle of the modified pigment is ≥90°, and the sedimentation rate in the ink system is ≤0.5mm / 24h.

[0010] Preferably, a gradient dispersion process for silicone-modified resin of high-blackness ink for LED display encapsulation includes the following steps: Preparation of S1 pre-dispersion system: Add organosilicon modified resin and high-purity solvent to a high-speed disperser and stir and mix for 20-40 minutes at 800-1500 r / min and 25-35℃ to form a homogeneous resin solution. S2 Gradient Dispersion Stage: High-blackness composite pigment and polymeric dispersant are added in three stages. In the first stage, 1 / 3 of the pigment and 1 / 2 of the dispersant are added and dispersed at 1500-2500 r / min and 35-45℃ for 30-60 min. In the second stage, 1 / 3 of the pigment and the remaining dispersant are added and dispersed at 2500-4000 r / min and 45-55℃ for 60-90 min. In the third stage, the remaining 1 / 3 of the pigment is added and dispersed at 4000-6000 r / min and 55-65℃ for 90-120 min, achieving gradient pigment coating. S3 Grinding and Refining: The gradient-dispersed system is transferred to a sand mill and ground for 1-3 hours using 0.1-0.3 mm zirconia beads, controlling the particle size distribution of the system to D90≤1μm and D50≤300nm; S4 viscosity adjustment and post-treatment: Cool to 25-30℃, add functional additives, stir at 800-1200r / min for 20-30min, adjust the ink viscosity to 1000-5000mPa・s, filter through a 0.5-1μm filter membrane to obtain a uniform and stable high blackness encapsulation ink.

[0011] Preferably, the S2 gradient dispersion stage uses ultrasonic-assisted dispersion with an ultrasonic frequency of 20-40kHz and a power of 100-300W. The ultrasonic time in each stage is 1 / 3 of the stirring time, and ultrasonication and stirring are performed alternately. During the dispersion process, the particle size is monitored in real time by an online particle size analyzer. When D90 drops below 2μm, the next stage is entered.

[0012] Preferably, the preparation process of the organosilicon modified resin is as follows: epoxy resin or acrylic resin is added to a reaction vessel, heated to 80-100°C, a silane coupling agent and 0.1-0.5 wt% of a catalyst are added, the catalyst being dibutyltin dilaurate or stannous octoate, the mixture is kept warm and stirred for 2-4 hours, and low-boiling substances are removed by vacuum distillation to obtain the organosilicon modified resin; when the modified resin is an epoxy resin substrate, the epoxy value is 0.2-0.5 eq / 100g, and when it is an acrylic resin substrate, the acid value is ≤10mgKOH / g.

[0013] Preferably, the ink is thermosetting or UV-cured to form an encapsulation film with a thickness of 5-50 μm; the film has an L* value of ≤12, a visible light transmittance of 400-760 nm of ≤0.3%, and a blue light blocking rate of 450-470 nm emitted by the LED chip of ≥99.8%; and the film has an adhesion of ≥5B to the aluminum, glass or FR-4 substrate of the LED.

[0014] Compared with the prior art, the advantages and positive effects of the present invention are as follows: The silicone-modified resin not only provides excellent resistance to high and low temperatures and anti-yellowing properties, but its unique molecular structure also facilitates the wetting and coating of pigment particles. Most importantly, the three-stage gradient dispersion process, combined with online monitoring, achieves a gradual dispersion of pigments from initial wetting to deep coating through stepwise increases in rotation speed and temperature, and ultrasonic assistance. This ensures the nanoscale uniform distribution and long-term stability of the pigments within the resin. The resulting ink possesses comprehensive advantages such as high blackness, low light transmittance, strong adhesion, and a wide process window, perfectly meeting the encapsulation requirements of high-end LED displays. Attached Figure Description

[0015] Figure 1 This is a system flowchart of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] In the description of this invention, it should be understood that the terms length, width, up, down, front, back, left, right, vertical, horizontal, top, bottom, inside, outside, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "multiple" means two or more, unless otherwise explicitly specified.

[0018] according to Figure 1 As shown, this invention proposes a high-blackness ink formulation for LED display packaging and a gradient dispersion process for silicone-modified resin. By mass, it consists of 8-20 parts of high-blackness composite pigment, 30-50 parts of silicone-modified resin, 2-8 parts of polymeric dispersant, 1-5 parts of functional additives, and 15-35 parts of high-purity solvent. The process achieves gradient dispersion of silicone-modified resin by adjusting the dispersion speed and temperature in stages, so that pigment particles are uniformly coated on the resin matrix. After the ink is cured, a high blackness and low light transmittance encapsulation film layer is formed, which is suitable for the light-shielding encapsulation requirements of LED display devices.

[0019] As an optional embodiment, the high-blackness composite pigment is composed of carbon black and titanium black in a mass ratio of 3-5:1; the carbon black is furnace black with a particle size of 15-40 nm and a specific surface area of ​​80-150 m². 2 / g, oil absorption value 1.0-1.8mL / g; titanium black is Ti4O7 or Ti3O5, particle size 20-50nm, blackness L* value ≤15, visible light transmittance ≤0.5%.

[0020] As an optional embodiment, the organosilicon modified resin uses epoxy resin or acrylic resin as the base material and is grafted modified by silane coupling agents KH-560, KH-570 or KH-792; the modified resin has a silicon content of 3-8wt%, a viscosity of 1000-8000mPa・s at 25°C, a solid content of 60%-80%, a glass transition temperature of 80-150°C, and a temperature resistance range of -40-200°C.

[0021] As an optional embodiment, the polymeric dispersant is a mixture of polyurethane dispersant and polyether dispersant in a mass ratio of 1-2:1; the polyurethane dispersant is selected from BYK-163 and EFKA-4046, and the polyether dispersant is selected from BYK-180 and TEGODispers750W; the total amount of dispersant is 10%-40% of the mass of the high-blackness composite pigment.

[0022] As an optional embodiment, the functional additive is composed of defoamer, leveling agent and antioxidant in a mass ratio of 2-3:1-2:1; the defoamer is selected from organosilicon BYK-055 and polyether EFKA-2020, the leveling agent is selected from acrylate TEGOFlow370, and the antioxidant is selected from hindered phenol 1010 and phosphite 168; the high-purity solvent is selected from one or more of propylene glycol methyl ether acetate, butyl acetate and cyclohexanone, the solvent water content is ≤0.3%, the purity is ≥99.5%, and the evaporation rate at 25°C is 0.3-0.8 times that of ethyl acetate.

[0023] As an optional embodiment, the high-blackness composite pigment undergoes surface modification treatment, with the modifier being a titanate coupling agent or an aluminate coupling agent, and the amount used is 1%-3% of the pigment mass; the water contact angle of the modified pigment is ≥90°, and the sedimentation rate in the ink system is ≤0.5mm / 24h.

[0024] As an optional embodiment, a gradient dispersion process for silicone-modified resin of high-blackness ink for LED display encapsulation includes the following steps: Preparation of S1 pre-dispersion system: Add organosilicon modified resin and high-purity solvent to a high-speed disperser and stir and mix for 20-40 minutes at 800-1500 r / min and 25-35℃ to form a homogeneous resin solution. S2 Gradient Dispersion Stage: High-blackness composite pigment and polymeric dispersant are added in three stages. In the first stage, 1 / 3 of the pigment and 1 / 2 of the dispersant are added and dispersed at 1500-2500 r / min and 35-45℃ for 30-60 min. In the second stage, 1 / 3 of the pigment and the remaining dispersant are added and dispersed at 2500-4000 r / min and 45-55℃ for 60-90 min. In the third stage, the remaining 1 / 3 of the pigment is added and dispersed at 4000-6000 r / min and 55-65℃ for 90-120 min, achieving gradient pigment coating. S3 Grinding and Refining: The gradient-dispersed system is transferred to a sand mill and ground for 1-3 hours using 0.1-0.3 mm zirconia beads, controlling the particle size distribution of the system to D90≤1μm and D50≤300nm; S4 viscosity adjustment and post-treatment: Cool to 25-30℃, add functional additives, stir at 800-1200r / min for 20-30min, adjust the ink viscosity to 1000-5000mPa・s, filter through a 0.5-1μm filter membrane to obtain a uniform and stable high blackness encapsulation ink.

[0025] As an optional embodiment, the S2 gradient dispersion stage uses ultrasonic-assisted dispersion with an ultrasonic frequency of 20-40kHz and a power of 100-300W. The ultrasonic time in each stage is 1 / 3 of the stirring time, and ultrasonication and stirring are performed alternately. During the dispersion process, the particle size is monitored in real time by an online particle size analyzer. When D90 drops below 2μm, the next stage is entered.

[0026] As an optional embodiment, the preparation process of the organosilicon modified resin is characterized by: adding epoxy resin or acrylic resin to a reaction vessel, heating to 80-100℃, adding a silane coupling agent and 0.1-0.5wt% of a catalyst, the catalyst being dibutyltin dilaurate or stannous octoate, keeping the mixture heated and stirred for 2-4 hours, removing low-boiling substances by vacuum distillation to obtain the organosilicon modified resin; when the modified resin is an epoxy resin substrate, the epoxy value is 0.2-0.5 eq / 100g, and when it is an acrylic resin substrate, the acid value is ≤10mgKOH / g.

[0027] As an optional embodiment, the ink is thermosetting or UV-cured to form an encapsulation film with a thickness of 5-50 μm; the film has an L* value of ≤12, a visible light transmittance of 400-760 nm of ≤0.3%, and a blue light blocking rate of 450-470 nm emitted by the LED chip of ≥99.8%; the film has an adhesion of ≥5B to the LED substrate aluminum, glass or FR-4.

[0028] Example 1; 1. Raw materials and formula (by mass parts);

[0029] 2. Preparation steps; Preparation of S1 organosilicon modified resin; 40 parts of epoxy resin were added to a reaction vessel; the temperature was raised to 90℃; 0.14 parts of dibutyltin dilaurate and the corresponding amount of silane coupling agent KH-560 were added; the mixture was kept at this temperature and stirred for 3 hours; low-boiling substances were removed by vacuum distillation; and organosilicon modified resin was obtained. S2 high-blackness composite pigment modification; 14 parts of composite pigment were mixed with 0.28 parts of titanate coupling agent; the mixture was stirred at 80℃ and 500r / min for 1h to modify the surface; and then cooled to room temperature to obtain the surface-modified composite pigment. Preparation of S3 pre-dispersion system; The above-mentioned organosilicon-modified resin and 25 parts of high-purity solvent were added to a high-speed disperser; the mixture was stirred and mixed at 1200 r / min and 30℃ for 30 min to form a homogeneous resin solution; S4 gradient dispersion stage; In the first stage, 4.67 parts of modified composite pigment and 2.5 parts of polymeric dispersant were added; dispersion was carried out at 2000 r / min and 40℃ for 45 min; ultrasonic-assisted dispersion was then performed at a frequency of 30 kHz, a power of 200 W, and a sonication time of 15 min, alternating with stirring; monitoring showed that D90 decreased to below 2 μm. In the second stage, 4.67 parts of modified composite pigment and 2.5 parts of polymeric dispersant were added; dispersion was carried out at 3200 r / min and 50℃ for 75 min; ultrasonic-assisted dispersion was performed at a frequency of 30 kHz, a power of 200 W, and a sonication time of 25 min; monitoring showed that D90 decreased to below 1.5 μm. In the third stage, 4.66 parts of modified composite pigment were added; dispersion was carried out at 5000 r / min and 60℃ for 105 min; ultrasonic-assisted dispersion was performed at a frequency of 30 kHz, a power of 200 W, and a sonication time of 35 min; achieving gradient pigment coating. S5 grinding refinement; The gradient-dispersed system was transferred to a sand mill and ground for 2 hours using 0.2 mm zirconia beads. The particle size distribution of the system was controlled as D90 = 0.8 μm and D50 = 220 nm. S6 Adhesion Adjustment and Post-treatment; Cool to 28℃; add 3 parts of functional additives; stir at 1000 r / min for 25 min; adjust the ink viscosity to 3000 mPa・s (25℃); filter through a 0.8 μm filter membrane; obtain a uniform and stable high blackness encapsulation ink; 3. Performance test results;

[0030] II. Example 2 1. Raw materials and formula (by mass parts);

[0031] 2. Preparation steps; Preparation of S1 organosilicon modified resin; Add 30 parts of acrylic resin to a reactor; heat to 80℃; add 0.03 parts of stannous octoate and the corresponding amount of silane coupling agent KH-570; keep warm and stir for 2 hours; remove low-boiling substances by vacuum distillation; obtain organosilicon modified resin; S2 high-blackness composite pigment modification; Eight parts of composite pigment were mixed with 0.08 parts of aluminate coupling agent; the mixture was stirred at 70℃ and 400r / min for 1h to modify the surface; and then cooled to room temperature to obtain the surface-modified composite pigment. Preparation of S3 pre-dispersion system; The above-mentioned organosilicon-modified resin and 15 parts of high-purity solvent were added to a high-speed disperser and stirred and mixed at 800 r / min and 25℃ for 20 min to form a homogeneous resin solution. S4 gradient dispersion stage; In the first stage, 2.67 parts of modified composite pigment and 1 part of polymeric dispersant were added; dispersion was carried out at 1500 r / min and 35℃ for 30 min; ultrasonic-assisted dispersion was then performed at a frequency of 20 kHz, a power of 100 W, and an ultrasonic time of 10 min, alternating with stirring; monitoring showed that D90 decreased to below 2 μm. In the second stage, 2.67 parts of modified composite pigment and 1 part of polymeric dispersant were added; dispersion was carried out at 2500 r / min and 45℃ for 60 min; ultrasonic-assisted dispersion was performed at a frequency of 20 kHz, a power of 100 W, and an ultrasonic time of 20 min; monitoring showed that D90 decreased to below 1.5 μm. In the third stage, 2.66 parts of modified composite pigment were added; dispersion was carried out at 4000 r / min and 55℃ for 90 min; ultrasonic-assisted dispersion was performed at a frequency of 20 kHz, a power of 100 W, and an ultrasonic time of 30 min; achieving gradient pigment coating. S5 grinding refinement; The gradient-dispersed system was transferred to a sand mill and ground for 1 hour using 0.1 mm zirconia beads. The particle size distribution of the system was controlled as D90 = 1.0 μm and D50 = 300 nm. S6 Adhesion Adjustment and Post-treatment; Cool to 25℃; add 1 part functional additive; stir at 800 r / min for 20 min; adjust the ink viscosity to 1000 mPa・s (25℃); filter through a 0.5 μm filter membrane; obtain a uniform and stable high blackness encapsulation ink; 3. Performance test results;

[0032] III. Example 3; IV. 1. Raw materials and formula (by mass parts);

[0033] 2. Preparation steps; Preparation of S1 organosilicon modified resin; 50 parts of epoxy resin were added to a reaction vessel; the temperature was raised to 100℃; 0.25 parts of dibutyltin dilaurate and the corresponding amount of silane coupling agent KH-792 were added; the mixture was kept at this temperature and stirred for 4 hours; low-boiling substances were removed by vacuum distillation; and organosilicon modified resin was obtained. S2 high-blackness composite pigment modification; 20 parts of composite pigment were mixed with 0.6 parts of titanate coupling agent; the mixture was stirred at 90℃ and 600r / min for 1h to modify the surface; and then cooled to room temperature to obtain the surface-modified composite pigment. Preparation of S3 pre-dispersion system; The above-mentioned organosilicon-modified resin and 35 parts of high-purity solvent were added to a high-speed disperser and stirred at 1500 r / min and 35℃ for 40 min to form a homogeneous resin solution. S4 gradient dispersion stage; In the first stage, 6.67 parts of modified composite pigment and 4 parts of polymeric dispersant were added; dispersion was carried out at 2500 r / min and 45℃ for 60 min; ultrasonic-assisted dispersion was then performed at a frequency of 40 kHz, a power of 300 W, and a sonication time of 20 min, alternating with stirring; monitoring showed that D90 decreased to below 2 μm. In the second stage, 6.67 parts of modified composite pigment and 4 parts of polymeric dispersant were added; dispersion was carried out at 4000 r / min and 55℃ for 90 min; ultrasonic-assisted dispersion was performed at a frequency of 40 kHz, a power of 300 W, and a sonication time of 30 min; monitoring showed that D90 decreased to below 1.5 μm. In the third stage, 6.66 parts of modified composite pigment were added; dispersion was carried out at 6000 r / min and 65℃ for 120 min; ultrasonic-assisted dispersion was performed at a frequency of 40 kHz, a power of 300 W, and a sonication time of 40 min; achieving gradient pigment coating. S5 grinding refinement; The gradient-dispersed system was transferred to a sand mill and ground for 3 hours using 0.3 mm zirconia beads. The particle size distribution of the system was controlled as D90 = 0.6 μm and D50 = 180 nm. S6 Adhesion Adjustment and Post-treatment; Cool to 30℃; add 5 parts of functional additives; stir at 1200r / min for 30min; adjust the ink viscosity to 5000mPa.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A high-blackness ink formulation for LED display encapsulation, characterized in that, By mass fraction, it consists of 8-20 parts of high-blackness composite pigment, 30-50 parts of organosilicon modified resin, 2-8 parts of polymeric dispersant, 1-5 parts of functional additives, and 15-35 parts of high-purity solvent. The process achieves gradient dispersion of silicone-modified resin by adjusting the dispersion speed and temperature in stages, so that pigment particles are uniformly coated on the resin matrix. After the ink is cured, a high blackness and low light transmittance encapsulation film layer is formed, which is suitable for the light-shielding encapsulation requirements of LED display devices.

2. The high-blackness ink formulation for LED display encapsulation according to claim 1, characterized in that, High-blackness composite pigments are composed of carbon black and titanium black in a mass ratio of 3-5:1; the carbon black is furnace black with a particle size of 15-40 nm and a specific surface area of ​​80-150 m². 2 / g, oil absorption value 1.0-1.8mL / g; titanium black is Ti4O7 or Ti3O5, particle size 20-50nm, blackness L* value ≤15, visible light transmittance ≤0.5%.

3. The high-blackness ink formulation for LED display encapsulation according to claim 2, characterized in that, The organosilicon-modified resin uses epoxy resin or acrylic resin as the base material and is grafted and modified by silane coupling agents KH-560, KH-570 or KH-792. The modified resin has a silicon content of 3-8wt%, a viscosity of 1000-8000mPa・s at 25℃, a solid content of 60%-80%, a glass transition temperature of 80-150℃, and a temperature resistance range of -40-200℃.

4. The high-blackness ink formulation for LED display encapsulation according to claim 1, characterized in that, The polymeric dispersant is a mixture of polyurethane dispersant and polyether dispersant in a mass ratio of 1-2:1; the polyurethane dispersant is selected from BYK-163 and EFKA-4046, and the polyether dispersant is selected from BYK-180 and TEGODispers750W; the total amount of dispersant is 10%-40% of the mass of the high-blackness composite pigment.

5. The high-blackness ink formulation for LED display encapsulation according to claim 4, characterized in that, The functional additives are compounded from defoamer, leveling agent and antioxidant in a mass ratio of 2-3:1-2:1; the defoamer is selected from organosilicon BYK-055 and polyether EFKA-2020, the leveling agent is selected from acrylate TEGOFlow370, and the antioxidant is selected from hindered phenol 1010 and phosphite 168; the high-purity solvent is selected from one or more of propylene glycol methyl ether acetate, butyl acetate and cyclohexanone, the solvent water content is ≤0.3%, the purity is ≥99.5%, and the evaporation rate at 25℃ is 0.3-0.8 times that of ethyl acetate.

6. The high-blackness ink formulation for LED display encapsulation according to claim 1, characterized in that, The high-blackness composite pigment undergoes surface modification treatment. The modifier is a titanate coupling agent or an aluminate coupling agent, and the amount used is 1%-3% of the pigment mass. After modification, the water contact angle of the pigment is ≥90°, and the sedimentation rate in the ink system is ≤0.5mm / 24h.

7. A gradient dispersion process for organosilicon-modified resin in high-blackness ink for LED display encapsulation, characterized in that, The gradient dispersion process of the organosilicon-modified resin includes the following steps: Preparation of S1 pre-dispersion system: Add organosilicon modified resin and high-purity solvent to a high-speed disperser and stir and mix for 20-40 minutes at 800-1500 r / min and 25-35℃ to form a homogeneous resin solution. S2 Gradient Dispersion Stage: High-blackness composite pigment and polymeric dispersant are added in three stages. In the first stage, 1 / 3 of the pigment and 1 / 2 of the dispersant are added and dispersed at 1500-2500 r / min and 35-45℃ for 30-60 min. In the second stage, 1 / 3 of the pigment and the remaining dispersant are added and dispersed at 2500-4000 r / min and 45-55℃ for 60-90 min. In the third stage, the remaining 1 / 3 of the pigment is added and dispersed at 4000-6000 r / min and 55-65℃ for 90-120 min, achieving gradient pigment coating. S3 Grinding and Refining: The gradient-dispersed system is transferred to a sand mill and ground for 1-3 hours using 0.1-0.3 mm zirconia beads, controlling the particle size distribution of the system to D90≤1μm and D50≤300nm; S4 viscosity adjustment and post-treatment: Cool to 25-30℃, add functional additives, stir at 800-1200r / min for 20-30min, adjust the ink viscosity to 1000-5000mPa・s, filter through a 0.5-1μm filter membrane to obtain a uniform and stable high blackness encapsulation ink.

8. The high-blackness ink formulation for LED display encapsulation and the gradient dispersion process of organosilicon-modified resin according to claim 7, characterized in that, The S2 gradient dispersion stage employs ultrasonic-assisted dispersion with an ultrasonic frequency of 20-40kHz and a power of 100-300W. The ultrasonic time in each stage is 1 / 3 of the stirring time, and ultrasonication and stirring are performed alternately. During the dispersion process, the particle size is monitored in real time by an online particle size analyzer. When D90 drops below 2μm, the next stage begins.

9. The high-blackness ink formulation for LED display encapsulation and the gradient dispersion process of organosilicon-modified resin according to claim 3, characterized in that, The preparation process of organosilicon modified resin is as follows: epoxy resin or acrylic resin is added to a reaction vessel, heated to 80-100℃, and a silane coupling agent and 0.1-0.5wt% of catalyst are added. The catalyst is dibutyltin dilaurate or stannous octoate. The mixture is kept at this temperature and stirred for 2-4 hours. Low-boiling substances are removed by vacuum distillation to obtain organosilicon modified resin. When the modified resin is based on epoxy resin, the epoxy value is 0.2-0.5 eq / 100g. When it is based on acrylic resin, the acid value is ≤10mgKOH / g.

10. The high-blackness ink formulation for LED display encapsulation and the gradient dispersion process of organosilicon-modified resin according to claim 1, characterized in that, The ink is heat-cured or UV-cured to form an encapsulation film with a thickness of 5-50 μm; the film has an L* value of ≤12, a visible light transmittance of 400-760 nm of ≤0.3%, and a blue light blocking rate of 450-470 nm emitted by the LED chip of ≥99.8%; the film has an adhesion of ≥5B to the aluminum, glass or FR-4 of the LED substrate.

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