Inkjet printing material, method for producing the same, and inkjet printed sheet

Abstract

This invention proposes an inkjet printing material, its preparation method, and inkjet printing paper. The preparation method of the inkjet printing material includes: adding deionized water and calcium carbonate to a container and performing grinding and / or dispersion treatment; after a first time of grinding or dispersion treatment, reducing the rotation speed, adding a coupling agent and an organic solvent to the container, and continuing grinding or dispersion treatment for a second time to obtain a pigment dispersion; mixing the pigment dispersion with a resin solution to obtain the inkjet printing material. Therefore, the inkjet printing material prepared by this method can effectively intercept pigments in the ink, allowing the pigments to remain on the coating surface, thereby improving color density and reducing ink consumption.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing technology, specifically to inkjet printing materials, their preparation methods, and inkjet printing paper. Background Technology

[0002] In March 2019, Fujifilm launched the new Jet Press 750S digital inkjet printer in Japan, ushering in a new era of inkjet printing. Building upon the high quality, high output speed, and high stability of the series, the Jet Press 750S features the latest "SAMBA" printhead, high-performance water-based pigment ink "VIVIDIA," and a newly developed drying system. As the next-generation flagship model after the Jet Press 720S series, it redefines a third printing method beyond traditional offset and digital inkjet printing, and is expected to shine in many printing fields such as imaging, anti-counterfeiting, packaging, and commercial printing. The printing speed has increased to 3,600 sheets per hour, and the paper size has increased to 750mm × 585mm. Currently, there are not many consumables suitable for this printing press. The 750S uses water-based pigment ink, and its high-speed printing characteristics give this ink high penetration. However, currently used consumables such as coated paper and PP paper have relatively large pores. For example, while the numerous pits and fibers on coated paper provide excellent ink absorption, the pore size formed by the accumulation of particles is mostly greater than 0.5μm. When printing on coated paper or PP paper with water-based pigment ink, the ink quickly penetrates into the pores, reducing print density. To achieve the set color density, more ink needs to be sprayed, increasing printing costs. On coated paper, the ink quickly penetrates into the coating.

[0003] Therefore, current inkjet printing materials, their preparation methods, and inkjet printing paper still need improvement. Summary of the Invention

[0004] The present invention aims to at least alleviate or even solve at least one of the aforementioned problems to some extent.

[0005] In one aspect, this invention provides a method for preparing an inkjet printing material. In some embodiments of this invention, the method for preparing the inkjet printing material includes: adding deionized water and calcium carbonate to a container and performing grinding and / or dispersion treatment; after a first time of grinding or dispersion treatment, reducing the rotation speed, adding a coupling agent and an organic solvent to the container, and continuing grinding or dispersion treatment for a second time to obtain a pigment dispersion; mixing the pigment dispersion with a resin solution to obtain the inkjet printing material. Therefore, the inkjet printing material prepared by this method can effectively intercept pigments in the ink, allowing the pigments to remain on the coating surface, thereby improving color density and reducing ink consumption.

[0006] In some embodiments of the present invention, the method satisfies at least one of the following conditions: in the pigment dispersion, the amount of calcium carbonate with a particle size of 0.1 μm-0.3 μm accounts for 50%-75% of the total number of calcium carbonate particles; the coupling agent is a silane coupling agent; the organic solvent includes at least one of isopropanol and ethanol; the resin solution includes polyvinyl alcohol and / or polyurethane resin; in the container, deionized water is 500 parts by weight, calcium carbonate is 125-500 parts by weight, the coupling agent is 0.1-5 parts by weight, and the organic solvent is 1-10 parts by weight.

[0007] In some embodiments of the present invention, deionized water and calcium carbonate are added to the container, and the grinding process is carried out at a speed of 2000-2500 rpm for a first time of 20-30 minutes. The speed is then reduced to 800-1200 rpm, and the grinding temperature is maintained at 40-80 degrees Celsius. The coupling agent and the organic solvent are added to the container, and grinding continues for a second time of 20-40 minutes. Optionally, the diameter of the grinding beads used in the grinding process is 0.6 mm-0.8 mm. Thus, the particle size distribution of calcium carbonate particles can be controlled through grinding, ensuring that the particle size is within a suitable range.

[0008] In some embodiments of the present invention, deionized water and calcium carbonate are added to the container, and the dispersion process is carried out at a rotation speed of 8000-10000 rpm for a first time of 20-30 minutes, maintaining the dispersion temperature at 40-80 degrees Celsius. The rotation speed is then reduced to 5000-6000 rpm, and the coupling agent and organic solvent are added to the container, with dispersion continuing for a second time of 20-30 minutes. This rapid dispersion process also allows the particle size of calcium carbonate to be controlled within a suitable range.

[0009] In some embodiments of the present invention, when the pigment dispersion is mixed with the resin solution, the mass ratio of calcium carbonate in the pigment dispersion to resin in the resin solution is 1:1.5-10:1.

[0010] In some embodiments of the present invention, the method further includes the step of adding a curing agent solution to the mixture of the pigment dispersion and the resin solution. Optionally, the curing agent solution includes at least one of aldehyde curing agents, boric acid, borate, chromium sulfate, and isocyanate. Optionally, the mass of the curing agent solution is 0.1%-20% of the mass of the resin solution.

[0011] In some embodiments of the present invention, before adding the curing agent solution to the mixture of the pigment dispersion and the resin solution, the step of adding a surfactant to the mixture of the pigment dispersion and the resin solution is further included.

[0012] In another aspect of the invention, an inkjet printing material is provided. In some embodiments of the invention, the inkjet printing material is prepared using the method described above. Therefore, this inkjet printing material can intercept pigments in the ink, leaving the pigments on the surface, improving pigment utilization, thereby increasing color density and reducing ink consumption.

[0013] In another aspect, the present invention provides an inkjet printing paper. In some embodiments of the invention, the inkjet printing paper is obtained by coating at least one side of a substrate with the aforementioned inkjet printing material and then drying it. Thus, the inkjet printing paper possesses all the features and advantages of the aforementioned inkjet printing material, which will not be repeated here.

[0014] In some embodiments of the present invention, the substrate includes PP synthetic paper or a plastic-coated substrate, and / or, after drying, the thickness of the coating on the substrate is 6μm-20μm. Attached Figure Description

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0016] Figure 1 Electron micrographs of coated paper are shown;

[0017] Figure 2 This shows a photograph of ink printed on coated paper;

[0018] Figure 3 An optical microscope image of inkjet-printed paper after ink has been printed according to an embodiment of the present invention is shown.

[0019] Figure 4 The image shown is a printout of an inkjet-printed paper according to an embodiment of the present invention. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] refer to Figure 1The pores formed by the accumulation of particles on coated paper are mostly larger than 0.5 μm. Therefore, although coated paper has a high porosity and strong ink absorption capacity, its large pore size allows pigment particles to penetrate into the coating. (Refer to...) Figure 2 This will reduce print density and color density. Lower print density means more ink needs to be sprayed to achieve the desired color density, increasing production costs. Consumables such as PP paper also suffer from similar problems, resulting in low pigment utilization in the ink.

[0022] In order to at least partially alleviate or even solve at least one of the aforementioned technical problems, this invention provides a method for preparing an inkjet printing material. In some embodiments of this invention, the method for preparing the inkjet printing material may include the following steps:

[0023] S100: Add deionized water and calcium carbonate to a container and perform grinding / or dispersion treatment.

[0024] In some embodiments of the present invention, the container may contain 500 parts by weight of deionized water and 125-500 parts by weight of calcium carbonate. For example, the deionized water may contain 500 parts by weight, and the calcium carbonate may contain 125 parts by weight, 150 parts by weight, 200 parts by weight, 250 parts by weight, 300 parts by weight, 350 parts by weight, 400 parts by weight, 450 parts by weight, or 500 parts by weight, etc.

[0025] In some embodiments of the present invention, the container may be a dispersion tank.

[0026] S200: After the first grinding or dispersion treatment, reduce the rotation speed, add coupling agent and organic solvent to the container, and continue grinding or dispersion treatment for a second time to obtain pigment dispersion.

[0027] In some embodiments of the present invention, the coupling agent can be a silane coupling agent. The silane coupling agent can modify the surface of calcium carbonate, adsorb calcium carbonate particles, and connect two or more calcium carbonate particles. During grinding or dispersion, the particle size can be adjusted to a suitable range. In some embodiments of the present invention, the general formula of the silane coupling agent is RSiX3, where R can be an amino, mercaptovinyl, chloropropyl, methacryloxy, or other groups, and X can be a hydrolyzable group, such as a halogen, alkoxy, or acyloxy group.

[0028] In some embodiments of the present invention, the organic solvent may include at least one of isopropanol (IPA) and ethanol. The aforementioned organic solvent can better disperse the coupling agent in the dispersion of deionized water and calcium carbonate, thereby better controlling the particle size of calcium carbonate. In some embodiments of the present invention, the organic solvent may be isopropanol, which has a suitable boiling point, volatilizes relatively mildly during coating, and is less likely to produce an uneven surface structure during coating, thus facilitating the formation of a smooth coating.

[0029] In some embodiments of the present invention, the coupling agent in the container can be 0.1-5 parts by weight, and the organic solvent can be 1-10 parts by weight. For example, the coupling agent can be 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, etc., and the organic solvent can be 1 part by weight, 2 parts by weight, 5 parts by weight, 7 parts by weight, 10 parts by weight, etc. The above-mentioned parts by weight of coupling agent can modify the surface of calcium carbonate and can connect two or more calcium carbonate particles together, making it easier to obtain calcium carbonate particles of suitable particle size by grinding or dispersing the calcium carbonate; the above-mentioned parts by weight of organic solvent can uniformly disperse the coupling agent in the mixture, thereby facilitating the control of the particle size distribution of calcium carbonate particles.

[0030] In some embodiments of the present invention, the amount of calcium carbonate with a particle size of 0.1 μm-0.3 μm in the pigment dispersion accounts for 50%-75% of the total number of calcium carbonate particles. For example, the amount of calcium carbonate with a particle size of 0.1 μm-0.3 μm can account for 50%, 55%, 60%, 65%, 70%, 75%, etc. of the total number of calcium carbonate particles. Thus, most of the calcium carbonate particles have a particle size in the range of 0.1 μm-0.3 μm, which is suitable for intercepting pigments in the ink.

[0031] In some embodiments of the present invention, deionized water and calcium carbonate are added to a container, and the grinding speed can be 2000-2500 rpm, for example, 2000 rpm, 2100 rpm, 2200 rpm, 2300 rpm, 2400 rpm, 2500 rpm, etc., and the first time can be 20-30 minutes, for example, 20 minutes, 22 minutes, 25 minutes, 27 minutes, 30 minutes, etc.; the speed is reduced to 800-1200 rpm (for example, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, etc.), the grinding temperature is maintained at 40-80 degrees Celsius, a coupling agent and organic solvent are added to the container, and grinding continues, and the second time can be 20-40 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, etc. Through the above grinding process, the number of calcium carbonate particles with a diameter in the range of 0.1μm-0.3μm can account for 50%-75% of the total number of calcium carbonate particles. Subsequently, by combining with resin materials, capillary pores with a pore size in the range of 0.1μm-0.5μm can be formed, thereby more effectively intercepting pigment particles in ink.

[0032] In some embodiments of the present invention, the diameter of the abrasive beads used in the grinding process can be 0.6mm-0.8mm. For example, the diameter of the abrasive beads can be 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc. The diameter of the abrasive beads is within the above range, which is beneficial to shorten the grinding time. Furthermore, the abrasive beads with the above diameter can grind more calcium carbonate particles to a particle size range of 0.1μm-0.3μm.

[0033] In other embodiments of the present invention, deionized water and calcium carbonate are added to a container, and the dispersion treatment is carried out at a rotation speed of 8000-10000 rpm, for example, 8000 rpm, 8500 rpm, 9000 rpm, 9500 rpm, 10000 rpm, etc., and the first time is 20-30 minutes, for example, 20 minutes, 23 minutes, 25 minutes, 28 minutes, 30 minutes, etc.; the rotation speed is reduced to 5000-6000 rpm (for example, 5000 rpm, 5300 rpm, 5500 rpm, 5700 rpm, 6000 rpm), the dispersion temperature is maintained at 40-80 degrees Celsius, a coupling agent and an organic solvent are added to the container, and dispersion continues, the second time is 20-30 minutes, for example, 20 minutes, 22 minutes, 25 minutes, 28 minutes, 30 minutes, etc. Through the above dispersion treatment, the number of calcium carbonate particles with a diameter in the range of 0.1μm-0.3μm can account for 50%-75% of the total number of calcium carbonate particles. When combined with resin, it can form capillaries with suitable pore size, thereby better intercepting pigment particles in ink and improving color density.

[0034] S300: Mix pigment dispersion with resin solution to obtain inkjet printing material.

[0035] In some embodiments of the present invention, the resin solution may include polyvinyl alcohol and / or polyurethane resin. In some embodiments of the present invention, the resin solution may include polyvinyl alcohol and polyurethane resin. The above-mentioned resin material can be combined with calcium carbonate particles to obtain a large number of capillaries, which allow water to pass through and retain pigment particles in the ink droplets.

[0036] In some embodiments of the present invention, the resin described above can be combined with calcium carbonate particles. The number of calcium carbonate particles with a particle size of 0.1μm-0.3μm accounts for 50%-75% of the total number of calcium carbonate particles. Appropriate particle size of calcium carbonate particles is more conducive to the formation of a large number of capillaries. The pore size of the capillaries is between 0.1μm and 0.5μm, which can more effectively intercept pigments in the pigment ink, allowing the pigments to remain on the coating surface, thereby significantly improving the color density. If the dispersed calcium carbonate particles are too coarse, it may result in larger pore sizes, reducing the effectiveness of intercepting pigment particles, decreasing the color density, and potentially causing feathering. If the dispersed calcium carbonate particles are too fine, it may result in fewer capillaries, a decrease in ink absorption rate, and the occurrence of accumulation or incomplete drying.

[0037] In some embodiments of the present invention, when the pigment dispersion is mixed with the resin solution (an aqueous solution of resin), the mass ratio of calcium carbonate in the pigment dispersion to resin in the resin solution can be 1:1.5-10:1. For example, the mass ratio of calcium carbonate to resin can be 1:1.5, 1:1, 2:1, 3:1, 5:1, 7:1 or 10:1. When the resin solution is added according to the above ratio, the resin can cooperate with the calcium carbonate to form capillaries with suitable pore size, thereby effectively intercepting pigment particles in the ink and keeping the pigment particles on the surface. This is beneficial to improving color density, reducing ink usage, and lowering printing costs.

[0038] In some embodiments of the present invention, the method for preparing inkjet printing materials may further include the step of adding a curing agent solution to a mixture of pigment dispersion and resin solution, wherein the mass of the curing agent solution can be 0.1%-20% of the mass of the resin solution, for example, the mass of the curing agent solution can be 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, etc. of the mass of the resin solution. A suitable mass ratio of curing agent solution to resin solution, within a suitable range, allows the resin to cure rapidly.

[0039] In some embodiments of the present invention, the curing agent solution may include at least one of aldehyde curing agents, boric acid, borates, chromium sulfate, and isocyanates. All of the above-mentioned curing agents can shorten the curing time of the resin, enabling rapid curing. In some specific embodiments of the present invention, the curing agent solution may include borates or boric acid.

[0040] In some embodiments of the present invention, before adding the curing agent solution to the mixture of pigment dispersion and resin solution, the method for preparing the inkjet printing material may further include the step of adding a surfactant to the mixture of pigment dispersion and resin solution. By adding a surfactant to the mixture, the surface tension of the mixture can be adjusted, making it easier to coat the mixture evenly on the substrate.

[0041] In another aspect of the invention, an inkjet printing material is provided. In some embodiments of the invention, the inkjet printing material is prepared using the method described above. Therefore, this inkjet printing material can effectively intercept pigment particles in the ink, leaving the pigment particles on the coating surface, thereby improving color density.

[0042] In another aspect, the present invention provides an inkjet printing paper. In some embodiments of the invention, the inkjet printing paper is obtained by coating at least one side of a substrate with the aforementioned inkjet printing material and then drying it. Thus, the inkjet printing paper possesses all the features and advantages of the aforementioned inkjet printing material, which will not be repeated here. In general, the inkjet printing paper can intercept pigments in the ink, leaving the pigments on the coating surface, thereby improving color density.

[0043] In some embodiments of the present invention, the substrate may include PP (polypropylene) synthetic paper or a plastic-coated substrate. It should be noted that a plastic-coated substrate refers to a substrate with a surface coated with plastic, that is, a substrate with a surface coated with a composite formed of high-density polyethylene, low-density polyethylene, and some masterbatches. In some embodiments of the present invention, the plastic-coated substrate may be a paper base with a plastic coating, a polypropylene with a plastic coating, or a PET (polyethylene terephthalate) with a plastic coating, but is not limited to the above materials.

[0044] In some embodiments of the present invention, the inkjet printing material may be coated on one side of the substrate. In other embodiments of the present invention, the inkjet printing material may be coated on both sides of the substrate.

[0045] In some embodiments of the present invention, after drying, the thickness of the coating on the substrate can be 6μm-20μm. For example, the coating thickness can be 6μm, 8μm, 10μm, 13μm, 15μm, 20μm, etc. A coating thickness within the above range can significantly improve the coating's pigment interception effect. It should be noted that the above thickness refers to the thickness of the coating located on one side of the substrate.

[0046] Figure 3 This is an optical microscope image of inkjet-printed paper after ink has been printed according to an embodiment of the present invention. Figure 3 As can be seen, inkjet printing paper can prevent the ink pigments from penetrating into the coating. The coating in inkjet printing paper can intercept the pigments and quickly absorb the water in the ink droplets, thus achieving fast drying while increasing the color density by 10%, thereby saving at least 10% of ink consumption. Figure 4 This is an image of the inkjet printing paper according to an embodiment of the present invention. As can be seen, the pattern is adsorbed onto the surface.

[0047] In summary, the method proposed in this invention prepares inkjet printing materials by treating calcium carbonate with a sand mill or high-speed disperser, resulting in 50%-75% of the calcium carbonate particles being 0.1μm-0.3μm in size. A suitable adhesive is used to create numerous capillaries with pore sizes between 0.1μm and 0.5μm. These capillaries allow water to pass through, trapping pigment particles from ink droplets and leaving the pigment on the coating surface, thereby increasing color density. Dispersion at different speeds breaks down the original particles to achieve a specific particle distribution range. Within this range, modification is performed, maintaining a slightly lower dispersion speed throughout the modification process to ensure the consistency of the modified particles and the formation of relatively uniform particles. This keeps the diameter of the voids formed during subsequent deposition within a certain range. Meanwhile, the inorganic pigment particles play a certain role in fixing the adhesive molecules, which helps to reduce the stress generated during the shrinkage of the three-dimensional structure and is beneficial to the overall flatness of the inkjet printing medium. The inkjet printing material prepared by the method proposed in this invention has excellent stress consistency. After being coated on the substrate, it will not warp and does not require secondary reshaping. It has excellent color and image detail performance.

[0048] The inkjet printing material prepared using the method proposed in this invention possesses the ability to spontaneously form numerous capillaries, exhibiting high porosity. The pore size is between 0.1 μm and 0.5 μm. Coating this inkjet printing material onto a substrate forms a coating, resulting in inkjet printing paper. This paper rapidly absorbs and fuses pigments from the ink onto the surface, preventing pigment penetration into the coating and firmly fusing the pigments to the surface. Simultaneously, it quickly allows water from ink droplets to penetrate into the coating, resulting in a maximum printing density 10% higher than coated paper and superior color and image detail. Under the same printing conditions, printing using the inkjet printing paper proposed in this invention produces richer colors, finer patterns, and no feathering in the image output. Especially in portrait printing, it achieves excellent detail, with no feathering observed in areas such as black hair.

[0049] The present invention will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments below are merely illustrative and do not limit the scope of the invention in any way. Furthermore, in the following embodiments, unless otherwise specified, the materials and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the later embodiments, conditions and methods known in the art can be used for processing.

[0050] Example 1

[0051] Set the circulating water in the dispersion tank to 40 degrees Celsius, weigh 500 grams of deionized water into the dispersion tank, then add 300 grams of OMY-2000 (Jiangsu Oumia Company) calcium carbonate, disperse at 10,000 rpm for 20 minutes, and then reduce the dispersion speed to 5,000 rpm.

[0052] Add 1 gram of 3-aminopropyltriethoxysilane to 10 grams of IPA, mix well, and then add to a dispersion tank. Disperse at 5000 rpm for 20 minutes to obtain a pigment dispersion.

[0053] Take 400g of pigment dispersion, add 100g (10% by mass) of PVA (1788) aqueous solution at a stirring rate of 50 rpm, stir for 15 minutes, then add 60g of U4000 (Alberdingk U4000 emulsion), stir for another 20 minutes, then add 15g of 1283 surfactant aqueous solution (80g / L), then add 2g (1.8g / L) of boric acid aqueous solution, stir for 5 minutes, and then coat it onto PP synthetic paper with a wire rod. The coating thickness after drying should be 10μm.

[0054] The product is dried in an 80-degree Celsius drying oven to obtain the final product.

[0055] Example 2

[0056] Set the circulating water in the dispersion tank to 80 degrees Celsius, weigh 500 grams of deionized water into the dispersion tank, then add 500 grams of OMY-2000 calcium carbonate, disperse at 8000 rpm for 20 minutes, and then reduce the dispersion speed to 6000 rpm.

[0057] Add 5 g of 3-glycidyl etheroxypropylmethyldiethoxysilane to 10 g of IPA, mix well, and then add to a dispersion tank. Disperse at 6000 rpm for 20 minutes to obtain a pigment dispersion.

[0058] Take 400g of pigment dispersion and add 600g (10% mass concentration) of PVA (1788) aqueous solution at a stirring rate of 50 rpm. Stir for 15 minutes, then add 20g of 1283 surfactant aqueous solution (80g / L), followed by 50g (1.8g / L) of boric acid aqueous solution. Stir for 5 minutes, then coat the solution onto the plastic-coated paper base with a wire rod, requiring a dry thickness of 8μm.

[0059] The product is dried in an 80-degree Celsius drying oven to obtain the final product.

[0060] Example 3

[0061] Set the circulating water in the dispersion tank to 60 degrees Celsius, weigh 500 grams of deionized water into the dispersion tank, then add 300 grams of ultrafine calcium carbonate from Zhongtian Mining Company, grind it with a sand mill at a speed of 2500 rpm, disperse for 20 minutes, and then reduce the dispersion speed to 1000 rpm.

[0062] Add 3 g of 3-glycidoxypropyltrimethoxysilane to 10 g of IPA, mix well, and then add to a dispersion tank. Disperse at 1000 rpm for 20 minutes to obtain a pigment dispersion.

[0063] Take 400g of pigment dispersion and add 50g of U4000 at a stirring speed of 50 rpm. Stir for 20 minutes and then add 15g of 1283 surfactant aqueous solution (80g / L). Coat the solution onto PP synthetic paper with a wire rod, requiring a dry thickness of 18μm.

[0064] The product is dried in an 80-degree Celsius drying oven to obtain the final product.

[0065] Comparative Example 1

[0066] Set the circulating water in the dispersion tank to 40 degrees Celsius, weigh 500 grams of deionized water into the dispersion tank, then add 300 grams of OMY-2000 (Jiangsu Oumia Company) calcium carbonate, and disperse at 10,000 rpm for 20 minutes to obtain the pigment dispersion.

[0067] Take 400g of pigment dispersion and add 100g (10% by mass) of PVA (1788) aqueous solution while stirring at 50 rpm. Stir for 15 minutes, then add 60g of U4000 (Alberdingk U4000 emulsion) and stir for another 20 minutes. Add 1g of 3-aminopropyltriethoxysilane to 10g of IPA and mix well. Stir for 5 minutes, then add 15g of 1283 surfactant aqueous solution (80g / L), followed by 2g (1.8g / L) boric acid aqueous solution. Stir for 5 minutes, then coat the solution onto PP synthetic paper using a wire rod to achieve a dry thickness of 10μm.

[0068] The product is dried in an 80-degree Celsius drying oven to obtain the final product.

[0069] Comparative Example 2

[0070] Weigh 500g of deionized water and put it into a preparation tank. Add 500g of OMY-2000 calcium carbonate at 300 rpm and stir for 20 minutes to obtain a pigment dispersion.

[0071] Take 400g of pigment dispersion and add 600g (10% by mass) of PVA (1788) aqueous solution at a stirring rate of 300 rpm. Stir for 15 minutes, then add 20g of 1283 surfactant aqueous solution (80g / L), followed by 50g (1.8g / L) of boric acid aqueous solution. Stir for 5 minutes and apply the solution to the coated paper base using a wire rod. The required dry thickness is 8μm.

[0072] The product is dried in an 80-degree Celsius drying oven to obtain the final product.

[0073] The products and coated paper in each embodiment and comparative example were tested according to the following method:

[0074] 1) Flatness

[0075] Cut the sample to A3 size, place it flat on a horizontal glass plate with the coating facing up, and measure the height of warpage using a ruler. Warpage less than or equal to 2mm is acceptable, while warpage exceeding 2mm is unacceptable.

[0076] 2) Ink absorption performance

[0077] Use a 750S inkjet printer to print test color levels and observe whether the ink dries immediately after printing.

[0078] 3) Color density

[0079] Test the maximum density of black levels printed by the 750S inkjet printer.

[0080] 4) Resolution

[0081] Using the 750S print test, we define "completely clear and visible" as acceptable, as this condition satisfies the requirement of expressing portrait details. "Blurred and blurred lines" is considered unacceptable, as it indicates poor expression of portrait details, such as hair strands and skin texture.

[0082] The test results are as follows:

[0083] Table 1. Test results of products and coated paper in each embodiment and comparative example.

[0084] flatness Ink absorption Maximum color density Resolution Example 1 qualified qualified 2.11 qualified Example 2 qualified qualified 2.09 qualified Example 3 qualified qualified 2.03 qualified Comparative Example 1 Unqualified Unqualified 1.9 Unqualified Comparative Example 2 Unqualified qualified 1.85 Unqualified Coated paper qualified qualified 1.91 Unqualified

[0085] As shown in Table 1, the inkjet printing material prepared by the method proposed in this invention forms a coating on the substrate to obtain inkjet printing paper. This inkjet printing paper has good flatness and ink absorption, high color density, and high resolution.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "other embodiments," and "some specific embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0087] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an inkjet printing material, characterized in that, include: Add deionized water and calcium carbonate to a container and grind or disperse them. After the first grinding or dispersion treatment, the rotation speed is reduced, and a coupling agent and an organic solvent are added to the container. After the second grinding or dispersion treatment is continued, a pigment dispersion is obtained. The pigment dispersion is mixed with a resin solution to obtain an inkjet printing material; In the pigment dispersion, the amount of calcium carbonate with a particle size of 0.1μm-0.3μm accounts for 50%-75% of the total number of calcium carbonate particles; The coupling agent is a silane coupling agent; The organic solvent includes at least one of isopropanol and ethanol; The resin solution includes polyvinyl alcohol and / or polyurethane resin; In the container, deionized water is 500 parts by weight, calcium carbonate is 125-500 parts by weight, the coupling agent is 0.1-5 parts by weight, and the organic solvent is 1-10 parts by weight; Deionized water and calcium carbonate are added to the container, and the grinding process is carried out at a speed of 2000-2500 rpm for 20-30 minutes. The speed is then reduced to 800-1200 rpm, and the grinding temperature is maintained at 40-80 degrees Celsius. The coupling agent and the organic solvent are added to the container, and the grinding continues for 20-40 minutes. The diameter of the abrasive beads used in the grinding process is 0.6mm-0.8mm; When the pigment dispersion is mixed with the resin solution, the mass ratio of calcium carbonate in the pigment dispersion to resin in the resin solution is 1:1.5-10:

1.

2. The method according to claim 1, characterized in that, Deionized water and calcium carbonate are added to the container, and the dispersion process is carried out at a speed of 8000-10000 rpm for 20-30 minutes. The speed is then reduced to 5000-6000 rpm, and the dispersion temperature is maintained at 40-80 degrees Celsius. The coupling agent and the organic solvent are added to the container, and dispersion continues for another 20-30 minutes.

3. The method according to claim 1, characterized in that, The method further includes the step of adding a curing agent solution to the mixture of the pigment dispersion and the resin solution. The curing agent solution includes at least one of aldehyde curing agents, boric acid, borate, chromium sulfate, and isocyanate; The mass of the curing agent solution is 0.1%-20% of the mass of the resin solution.

4. The method according to claim 3, characterized in that, Before adding the curing agent solution to the mixture of the pigment dispersion and the resin solution, the method further includes the step of adding a surfactant to the mixture of the pigment dispersion and the resin solution.

5. An inkjet printing material, characterized in that, The inkjet printing material is prepared using the method described in any one of claims 1-4.

6. An inkjet printing paper, characterized in that, The inkjet printing paper is obtained by coating at least one side of a substrate with the inkjet printing material of claim 5 and then drying it.

7. The inkjet printing paper according to claim 6, characterized in that, The substrate includes PP synthetic paper or plastic-coated substrate, and / or, after drying, the thickness of the coating on the substrate is 6μm-20μm.

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