Modified yellow pigment, and preparation method and application thereof

Abstract

The application belongs to the technical field of display materials, and relates to a modified yellow pigment and a preparation method and application thereof. The modified yellow pigment comprises a yellow pigment, an acrylic resin and a pigment yellow 74 derivative. The yellow pigment is C.I. Pigment Yellow 138. The acrylic resin has a molecular weight of 9000, an acid value of 125 and a solid content of 30%. The pigment yellow 74 derivative is provided. The modified yellow pigment is prepared by adding the acrylic resin and the pigment yellow 74 derivative in kneading, so that the brightness and contrast of the pigment after film formation are improved. The pigment yellow 74 derivative is a solid, and the addition of the salt in the kneading increases the shearing friction, which is beneficial to the kneading modification of the yellow pigment. In the post-treatment, an iron removal process is added. The iron is removed by an iron remover for the first time, and HCl and EDTA disodium salt are further added. The hydrochloric acid is used to convert the metal into metal ions, and then the EDTA disodium salt is added to form a stable water-soluble complex, so that the metal content in the pigment is reduced to the minimum.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of display materials, and particularly relates to a modified yellow pigment as well as a preparation method and application thereof. BACKGROUND

[0002] Liquid crystal display (LCD) is a display technology realized by utilizing the characteristics of liquid crystal materials. LCD is widely applied to various display devices, such as televisions, computer displays, mobile phones and smart wearable devices. With the continuous development of science and technology, the LCD technology is also continuously progressing, and is developing towards higher resolution, lower energy consumption, faster response speed and more intelligent functions.

[0003] Color filter is a key component of LCD, which is a red, green and blue three-color pattern formed on a transparent substrate such as glass. In order to form a red and green colored pattern, it is difficult to obtain the desired spectral graph only by red or green pigments, so a mixed yellow pigment is used to adjust the spectral graph. In order to achieve high transparency and high contrast, in addition to strict requirements for the basic red and green pigments in the color paste of the photoresist, the yellow pigment used for color matching requires high color purity, small particle size, stable viscosity, high brightness and high contrast after film formation.

[0004] The commercially available yellow Y-138 pigment has an attractive effect between pigments during grinding and dispersion, which can cause agglomeration, has a large particle size, the liquid is non-transparent, the brightness (Y value) is low, and the contrast is low. Even if too much dispersing agent is added during the dispersion process, it still cannot achieve a small particle size, transparent and stable state, so the direct use of commercially available ordinary yellow pigments to prepare color paste and photoresist composition cannot meet the requirements of Y value and contrast, and cannot be directly used. In order to improve the Y value and contrast of the ordinary yellow pigment to prepare color paste and photoresist composition to meet the requirements, currently, a kneading method is mostly used for surface treatment. For yellow pigments, kneading is generally carried out by adding salt and solvent in a kneader. Although the performance is improved by directly adding salt and solvent for kneading, too much dispersing agent needs to be added during grinding and dispersion to achieve stable dispersion effect. However, too much dispersing agent not only affects the adjustable range of photoresist, but also has an impact on the process, so it still cannot meet the requirements of pigments used in the display liquid crystal industry.

[0005] Chinese patent CN113881245B discloses a modified yellow pigment for photoresist, its preparation method and application, which adds a dispersing agent TSP (triphenyl ethenyl phenol polyoxyethylene ether) in kneading to obtain a yellow pigment easy to grind and disperse, thereby ensuring smaller particle size of prepared color paste and obtaining high contrast. Chinese patent CN111732840B discloses a modified yellow pigment for photoresist, its preparation method and application, which adds a dispersing agent DSS (sodium dioctyl sulfonate) in kneading. In the kneading process, DSS can be well attached to the surface of the pigment crushed by NaCl, increasing the interparticle repulsion stability, making the pigment particle size more uniform and stable after kneading, thereby ensuring smaller particle size of prepared color paste and obtaining high contrast. The above patents optimize the effect of kneading material by adding a dispersing agent in kneading, and the final yellow pigment can be more easily dispersed after being prepared into color paste, and the optical value after film formation is more optimal.

[0006] In addition, the control of the metal content in the pigment is also very important. If the metal content in the pigment is too high, especially sodium and iron, the content of sodium and iron will affect the movement of liquid crystal after the pigment is made into color paste and then into filter film, and finally affect the response speed of the display. A large amount of salt is used in the kneading process of the yellow pigment. In addition to sodium ions, there are also sodium and iron ions in the salt. The extrusion and friction of the pigment and the salt in the kneading process also causes the metal on the inner cavity wall to fall off. Therefore, while improving the brightness and contrast, it is also necessary to reduce the content of metal and metal ions. SUMMARY

[0007] The present application provides a modified yellow pigment, its preparation method and application to solve the problems of the prior art. The specific technical solutions are as follows:

[0008] The first object of the present application is to provide a modified yellow pigment, which comprises a yellow pigment, an acrylic resin and a pigment yellow 74 derivative; the yellow pigment is C.I. Pigment Yellow 138; the structural formula of the pigment yellow 74 derivative is shown as formula (1):

[0009]

[0010] Formula (1).

[0011] The modified yellow pigment of the present application adds a pigment yellow 74 derivative, which can be used as a yellow pigment synergist. The polarity of the acidic group is applied to the surface of the yellow pigment, which is easy to connect with the surface of the yellow pigment. This polar group makes the pigment not easy to agglomerate. In the preparation of color paste, the pigment yellow 74 derivative and the dispersing agent are very easy to mix. The pigment yellow 74 derivative is used in combination with the acrylic resin, so that the final color paste has small particle size, the yellow pigment is well dispersed, and the brightness and contrast are effectively improved.

[0012] Further, the acrylic resin has a molecular weight of 9000, an acid value of 125, and a solid content of 30%.

[0013] Further, the modified yellow pigment comprises, by mass parts, 100 parts of a yellow pigment, 6-35 parts of an acrylic resin, and 2-10 parts of a pigment yellow 74 derivative.

[0014] A second object of the present application is to provide a preparation method of the modified yellow pigment, which is prepared by heating and kneading a kneaded material of a yellow pigment, an acrylic resin, a pigment yellow 74 derivative, a salt, and diethylene glycol (DEG), and then post-treating the kneaded material.

[0015] Further, the mass ratio of the yellow pigment, the salt, and the diethylene glycol is 1:(4-15):(1-4).

[0016] Further, the temperature of the kneading is 50-90°C, preferably 60-80°C, and the kneading time is 30-50h, preferably 35-45h.

[0017] Further, the post-treatment method of the modified yellow pigment kneaded material comprises the following steps:

[0018] (1) dispersing the kneaded material into a slurry: placing the kneaded material into a dispersion barrel, soaking and stirring to disperse by adding hot pure water, until there is no lump in the material, and forming a slurry;

[0019] (2) primary iron removal of the slurry: circulating the slurry through an iron remover to perform primary iron removal by magnetic force;

[0020] (3) secondary iron removal of the slurry: adding hydrochloric acid to the slurry and stirring to perform secondary iron removal;

[0021] (4) primary salt and acid removal of the slurry: placing the slurry after secondary iron removal, drawing out the supernatant, and then adding hot pure water repeatedly twice to complete the primary salt and acid removal;

[0022] (5) fine removal of metal ions from the slurry: adding disodium ethylenediaminetetraacetate to the slurry stirred with hot pure water, stirring and dispersing, and then standing to draw out the supernatant;

[0023] (6) pigment cleaning: adding hot pure water to stir and disperse the material again, filtering the dispersed slurry, and filtering and cleaning the material with pure water until the conductivity of the water discharged from the filter is the same as the initial conductivity of the pure water, then taking out the filter cake, placing it into a dispersion barrel, adding hot pure water to stir and disperse it again into a slurry, and then passing the dispersed slurry through an iron remover to remove iron again, and then passing it through a plate and frame filter until the conductivity of the water discharged from the filter is the same as the initial conductivity of the pure water, taking out the filter cake, and completing the cleaning;

[0024] (7) drying: drying and crushing the filter cake to obtain the modified yellow pigment.

[0025] If the metal content in the pigment is too high, especially sodium and iron, after the pigment is made into a color paste and a photoresist film, the high content of sodium and iron will affect the movement of liquid crystal and ultimately affect the response speed of the display. Ethylenediaminetetraacetic acid disodium salt is an important complexing agent, which can form stable water-soluble complexes with alkaline earth metals, rare earth elements and transition metals, etc. In the present application, its role is to absorb the metal contained in the salt to form a water-soluble metal complex in the kneading process, and to dissolve in water and disappear in the washing process, so as to avoid the metal remaining in the pigment.

[0026] Further, the temperature of the hot purified water is 60-70℃.

[0027] Further, in the step (1), the stirring speed of the dispersion is 300-500 rpm, and the dispersion time is not less than 2h.

[0028] Further, in the step (3), after adding hydrochloric acid, the concentration of hydrochloric acid in the slurry is 1%, and the stirring time is 3-4h.

[0029] Further, in the step (5), the amount of ethylenediaminetetraacetic acid disodium salt added is 3-5% of the mass of the modified yellow pigment, and the dispersion time is not less than 1h.

[0030] The third object of the present application is to provide the use of the modified yellow pigment in the preparation of a yellow color paste.

[0031] Further, the yellow color paste comprises, by mass fraction, 10 parts of the modified yellow pigment; 15-20 parts of a resin; 5-12 parts of a dispersant; and 55-75 parts of a solvent; the resin is an acrylic resin with a molecular weight of 3000-10000 and an acid value of 80-130.

[0032] Further, the dispersant is a high molecular dispersant, which can be BYK-2001, BYK-2000, BYK-2025, BYK-2050, BYK-2070, BYK-2150, BYK-167, BYK-168, BYK-170, BYK-171, BYK-181, BYK-182, etc.

[0033] Furthermore, the solvent is an organic solvent, which may be one or more of ether-based organic solvents and ether ester-based organic solvents. Specifically, ether-based organic solvents include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.; and ether ester-based organic solvents include ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, etc.

[0034] The beneficial effects of this invention are as follows:

[0035] This invention modifies the yellow pigment by adding acrylic resin and Pigment Yellow 74 derivative during kneading, thereby improving the brightness and contrast of the pigment after it is made into a color paste film. Pigment Yellow 74 derivative is a solid, and its addition during kneading increases the shear friction of the salt, which is beneficial for the kneading modification of the yellow pigment. In the post-treatment, an iron removal process is added. First, iron is removed once by an iron remover, and then HCl and disodium EDTA salt are added. Hydrochloric acid converts metals into metal ions, and then disodium EDTA salt is added to form a stable water-soluble complex, which is then removed with water, thus minimizing the metal content in the pigment. Attached Figure Description

[0036] Figure 1 This is the particle size distribution of the yellow pigment in Application Example 1 of the present invention;

[0037] Figure 2 This is the particle size distribution of the yellow pigment in Application Example 2 of the present invention;

[0038] Figure 3 This is the particle size distribution of the yellow pigment in Application Example 3 of the present invention;

[0039] Figure 4 The particle size distribution of the yellow pigment in Comparative Application Example 1 of this invention is shown in the diagram. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0041] Pigment Yellow 74 derivative: trade name PY74ASA-2, KISCO, South Korea.

[0042] Example 1:

[0043] Preparation of a modified yellow pigment:

[0044] Kneading modification: By weight, add 1700 parts salt, 200 parts CI pigment yellow 138, 4 parts pigment yellow 74 derivative, 40 parts acrylic resin (molecular weight 9000, acid value 125, solid content 30%), and 500 parts DEG to a 5-liter Inoue three-arm planetary mixer. Control the kneading temperature at 70℃ and the kneading time at 40h to obtain the kneaded material.

[0045] Post-processing:

[0046] (1) Disperse the kneaded material into a slurry: Put the kneaded material into a dispersion tank, add hot pure water at 60~70℃ to soak and stir to disperse. The dispersion speed is 400 rpm and the dispersion time is not less than 2 hours until the material is free of lumps and becomes a slurry.

[0047] (2) Preliminary iron removal from slurry: The slurry is circulated in a 10000GS iron separator for 2 hours, and preliminary iron removal is carried out by magnetic force;

[0048] (3) Secondary iron removal from slurry: Add hydrochloric acid to the slurry to make the overall hydrochloric acid concentration 1%, and stir for 4 hours to further remove iron from the pigment;

[0049] (4) Preliminary desalting and acid removal of slurry: After the slurry that has undergone two iron removals is allowed to stand, the supernatant is extracted, and hot pure water is added. This process is repeated twice to complete the preliminary desalting and acid removal.

[0050] (5) Fine removal of metal ions from slurry: Add 5% of the amount of modified yellow pigment disodium salt of EDTA to the slurry stirred with hot pure water and stir and disperse for a time of not less than 1 hour. After dispersion, let stand and extract the supernatant.

[0051] (6) Pigment cleaning: Add hot pure water again and stir to disperse the material. The dispersed slurry enters the plate and frame filter. Use pure water to filter and clean the material until the conductivity of the water discharged from the filter is the same as the initial conductivity of the pure water. Then remove the filter cake and put it into the dispersion tank. Add hot pure water again and stir to disperse it into a slurry. The dispersed slurry is circulated through the iron remover to remove iron and then enters the plate and frame filter until the conductivity of the filter drainage is the same as the initial conductivity of the pure water. Remove the filter cake and the cleaning is finished; (pure water conductivity <2us / cm);

[0052] (7) Drying: The material to be dried is evenly spread in a tray and dried at a constant temperature of 100℃ for 24 hours. Check and confirm whether the material has been dried. The dried material is crushed in a crusher to obtain modified yellow pigment Y-N1.

[0053] Example 2:

[0054] Preparation of a modified yellow pigment:

[0055] Kneading modification: By weight, add 2400 parts salt, 200 parts CI pigment yellow 138, 16 parts pigment yellow 74 derivative, 26.7 parts acrylic resin (molecular weight 9000, acid value 125, solid content 30%), and 400 parts DEG to a 5-liter Inoue three-arm planetary mixer. Control the kneading temperature at 70℃ and the kneading time at 40h to obtain the kneaded material.

[0056] The post-processing was the same as in Example 1, and will not be repeated here, to obtain the modified yellow pigment Y-N2.

[0057] Example 3:

[0058] Preparation of a modified yellow pigment:

[0059] Kneading modification: By weight, add 1000 parts salt, 200 parts CI pigment yellow 138, 10 parts pigment yellow 74 derivative, 53.3 parts acrylic resin (molecular weight 9000, acid value 125, solid content 30%), and 400 parts DEG to a 5-liter Inoue three-arm planetary mixer. Control the kneading temperature at 70℃ and the kneading time at 40h to obtain the kneaded material.

[0060] The post-processing was the same as in Example 1, and will not be repeated here, to obtain the modified yellow pigment Y-N3.

[0061] Comparative Example 1:

[0062] Preparation of a yellow pigment:

[0063] Kneading: By weight, add 1700 parts salt, 200 parts CI pigment yellow 138 and 500 parts DEG to a 5-liter Inoue three-arm planetary mixer, control the kneading temperature at 70℃ and the kneading time at 40h to obtain the kneaded material.

[0064] The post-processing was the same as in Example 1, and will not be repeated here, to obtain the modified yellow pigment YN-D1.

[0065] Comparative Example 2:

[0066] Preparation of a modified yellow pigment:

[0067] Kneading modification: Same as in Example 1, and will not be repeated here, to obtain kneaded material;

[0068] Post-processing:

[0069] (1) Dispersing kneaded material into slurry: Put the kneaded material into a dispersion tank, add hot pure water to soak and stir to disperse. The dispersion speed is 400 rpm and the dispersion time is not less than 2 hours until the material is free of lumps and becomes a slurry.

[0070] (2) Preliminary salt removal from slurry: Let the slurry stand, extract the supernatant, add hot pure water, repeat the process twice to complete the preliminary salt removal;

[0071] (3) Pigment cleaning: Add hot pure water again and stir to disperse the material. The dispersed slurry enters the plate and frame filter. Use pure water to filter and clean the material until the conductivity of the water discharged from the filter is the same as the initial conductivity of the pure water. Then remove the filter cake and put it into the dispersion tank. Add hot pure water again and stir to disperse it into a slurry. The dispersed slurry enters the plate and frame filter again until the conductivity of the filter drainage is the same as the initial conductivity of the pure water. Remove the filter cake and the cleaning is finished.

[0072] (4) Drying: The material to be dried is evenly spread in a tray and dried at a constant temperature of 100℃ for 24 hours. Check and confirm whether the material has been dried. The dried material is crushed in a crusher to obtain modified yellow pigment YN-D2.

[0073] Application Example 1:

[0074] Preparation of a yellow color paste: 10g of modified yellow pigment Y-N1, 9.6g of dispersant BYK-2001, 16.7g of acrylic resin (molecular weight 3000~10000, acid value 80~130), and 63.7g of propylene glycol methyl ether acetate solvent were added to a grinder, 0.1mm zirconium balls were added, and the grinding time was 24h. After grinding, a yellow color paste was obtained, and the particle size and viscosity were tested.

[0075] Film formation evaluation: The yellow pigment and acrylic resin (molecular weight 3000~10000, acid value 80~130) were mixed in a ratio of 5:0.5 and spin-coated onto the glass surface using a spin coater. The film was pre-baked at 90℃ for 90s on a pre-baking plate and then post-baked at 230℃ for 20min. After film formation, brightness (Y) and contrast were tested.

[0076] Application Example 2:

[0077] This application example uses the modified yellow pigment Y-N2, and everything else is the same as in application example 1, so it will not be repeated here.

[0078] Application Example 3:

[0079] This application example uses the modified yellow pigment Y-N3, and everything else is the same as in application example 1, so it will not be repeated here.

[0080] Comparative application example 1:

[0081] This application example uses the modified yellow pigment YN-D1. Everything else is the same as in application example 1, and will not be repeated here.

[0082] Compare with application example 2:

[0083] This application example uses the modified yellow pigment YN-D2, and everything else is the same as in application example 1, so it will not be repeated here.

[0084] Test methods and results:

[0085] Y-value test: High-precision color analyzer, model: HACA-3650;

[0086] Contrast ratio test: A contrast meter, model CT-1, was used.

[0087] Particle size testing: A particle size analyzer, model: 90Plus Pals, was used.

[0088] Viscosity testing: A viscometer, model: LVDV-2T, was used.

[0089] Fe and Na tests: ICP-OES method was used.

[0090] The test results are shown in Tables 1 and 2:

[0091] Table 1. Application Examples and Comparisons: Test Results of Yellow Pigment and Film Properties After Film Formation

[0092]

[0093] Table 2. Iron and sodium content in the modified yellow pigments of Example 1 and Comparative Example 2

[0094]

[0095] As can be seen from the results in Table 1, compared with Application Example 1 which uses direct kneading, although the Y value and contrast are improved, they still cannot meet the requirements. The pigment paste prepared in the application example has a small particle size, and after film formation, the brightness and contrast are greatly improved. This indicates that adding acrylic resin and Pigment Yellow 74 derivative to the kneading process improves the brightness and contrast of the pigment paste after film formation, and the effect is obvious.

[0096] As can be seen from the results in Table 2, the iron and sodium content in the modified yellow pigment was significantly reduced by using an iron remover and adding hydrochloric acid and disodium EDTA.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A modified yellow pigment, characterized in that, It includes a yellow pigment, acrylic resin, and a derivative of Pigment Yellow 74; the yellow pigment is CI Pigment Yellow 138; the structural formula of the Pigment Yellow 74 derivative is shown in formula (1): Equation (1).

2. The modified yellow pigment according to claim 1, characterized in that, The modified yellow pigment, by weight, comprises 100 parts yellow pigment, 6-35 parts acrylic resin, and 2-10 parts pigment yellow 74 derivative.

3. A method for preparing a modified yellow pigment as described in claim 1 or 2, characterized in that, The modified yellow pigment is produced by heating and kneading a mixture of yellow pigment, acrylic resin, pigment yellow 74 derivative, salt, and diethylene glycol, followed by post-processing of the kneaded mixture.

4. The method for preparing the modified yellow pigment according to claim 3, characterized in that, The mass ratio of the yellow pigment, salt and diethylene glycol is 1:(4~15):(1~4).

5. The method for preparing the modified yellow pigment according to claim 3, characterized in that, The kneading temperature is 50~90℃, and the kneading time is 30~50h.

6. The method for preparing the modified yellow pigment according to claim 3, characterized in that, The post-processing method for the modified yellow pigment kneaded material includes the following steps: (1) Dispersing kneaded material into slurry: Put the kneaded material into a dispersion tank, add hot pure water to soak and stir to disperse until the material is free of lumps and becomes slurry; (2) Preliminary iron removal from slurry: The slurry is circulated into the iron separator, where preliminary iron removal is performed by magnetic force; (3) Secondary iron removal from slurry: Add hydrochloric acid to the slurry and stir to remove iron for the second time; (4) Preliminary desalting and acid removal of slurry: After the slurry that has undergone two iron removals is allowed to stand, the supernatant is extracted, and hot pure water is added. This process is repeated twice to complete the preliminary desalting and acid removal. (5) Fine removal of metal ions from slurry: Add disodium ethylenediaminetetraacetate to the slurry stirred with hot pure water, stir and disperse, let stand, and extract the supernatant; (6) Pigment cleaning: Add hot pure water again and stir to disperse the material. Filter the dispersed slurry and use pure water to clean the material until the conductivity of the water discharged from the filter is the same as the initial conductivity of the pure water. Then remove the filter cake and put it into the dispersion tank. Add hot pure water again and stir to disperse it into a slurry. After the dispersed slurry is circulated through the iron remover to remove iron, it enters the plate and frame filter until the conductivity of the filter drainage is the same as the initial conductivity of the pure water. Remove the filter cake and the cleaning is finished. (7) Drying: Dry and crush the filter cake to obtain the modified yellow pigment.

7. The method for preparing the modified yellow pigment according to claim 6, characterized in that, In step (1), the stirring speed for dispersion is 300-500 rpm, and the dispersion time is not less than 2 hours.

8. The method for preparing the modified yellow pigment according to claim 6, characterized in that, In step (3), after adding hydrochloric acid, the concentration of hydrochloric acid in the slurry is 1%, and the mixture is stirred for 3-4 hours.

9. The modified yellow pigment according to claim 6, characterized in that, In step (5), the amount of disodium ethylenediaminetetraacetate added is 3-5% of the mass of the modified yellow pigment, and the dispersion time is not less than 1 hour.

10. The use of a modified yellow pigment as described in claim 1 or 2 in the preparation of yellow pigment paste.

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