Titanium dioxide for printing ink and its preparation method and application

Abstract

The present invention relates to a titanium dioxide for printing ink and its preparation method and application, and belongs to the technical field of modified titanium dioxide. Its preparation method comprises the following steps: first, a titanium dioxide precursor is immersed in a ruthenium salt solution, and after annealing and calcining, ruthenium and titanium dioxide are compounded to obtain a titanium dioxide-ruthenium composition, and then the titanium dioxide-ruthenium composition is grafted and modified with a silane coupling agent, and finally, polymethyl methacrylate-layered silicate mineral is wet-grinded to coat the surface of the modified titanium dioxide-ruthenium composition. The titanium dioxide obtained by the above method has high dispersibility, stability, anti-blocking, low wear and other properties, and a thin coating has high hiding and high gloss performance, which is suitable for ink printing.

Description

Technical Field

[0001] The present invention relates to the technical field of modified titanium dioxide, and in particular to titanium dioxide for printing ink, a preparation method and an application thereof. Background Art

[0002] Inks are the fourth largest application area for titanium dioxide, following coatings, plastics, and papermaking. As the core raw material for inks, titanium dioxide not only provides basic hiding power and tinting power, but also influences the ink's hiding power, printability, and color fastness. Titanium dioxide produced using different processes exhibits distinct characteristics in ink applications, resulting in significant performance differences.

[0003] There are two main types of titanium dioxide used in inks. One is for surface printing inks, which requires excellent dispersibility and gloss. The other is for back-printing inks, which requires excellent dispersibility and hiding power. Due to differences in production processes among manufacturers, the final performance of commercially available titanium dioxide products varies significantly. By adopting different grinding, dispersion, and inorganic coating processes, titanium dioxide can achieve different dispersibility and hiding power. Currently, in the back-printing ink market, it is difficult to achieve a balance between titanium dioxide dispersibility and hiding power. Most titanium dioxides meet the required dispersibility, but problems such as over-grinding can lead to poor hiding power. A small number of titanium dioxides provide relatively good hiding power, but performance in indicators such as dispersibility and oil absorption is poor. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a titanium dioxide for printing ink and its preparation method and application, which can simultaneously take into account the properties of dispersibility, stability, hiding power, glossiness and wear resistance, and is suitable for preparing printing ink.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a method for preparing titanium dioxide for printing ink, comprising the following steps:

[0007] S1: immersing a titanium dioxide precursor in a ruthenium salt solution, taking out the mixture, centrifugally drying it, and then annealing it to obtain a titanium dioxide-ruthenium composite;

[0008] S2: surface-modifying the titanium dioxide-ruthenium composition with a silane coupling agent to obtain a modified titanium dioxide-ruthenium composition;

[0009] S3: performing an in-situ polymerization reaction on the silicate mineral dispersion in the presence of an initiator, a methyl methacrylate monomer, and a linker to obtain a polymethyl methacrylate-layered silicate mineral;

[0010] S4: adding the modified titanium dioxide-ruthenium composition to a dispersion of polymethyl methacrylate-layered silicate mineral and grinding to obtain a mixture; then preparing the mixture into a dispersion; centrifuging the solid and drying it to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is the titanium dioxide for printing ink.

[0011] The preparation method of titanium dioxide powder of the present invention comprises the following steps: firstly immersing a titanium dioxide precursor in a ruthenium salt solution, annealing and calcining, then compounding ruthenium and titanium dioxide to obtain a titanium dioxide-ruthenium composition, then grafting and modifying the titanium dioxide-ruthenium composition with a silane coupling agent, and finally wet-grinding polymethyl methacrylate-layered silicate mineral so that it covers the surface of the modified titanium dioxide-ruthenium composition.

[0012] Ruthenium and its compounds have good chemical stability at room temperature and are not easy to react with oxygen or other chemicals in the air. Therefore, ruthenium is compounded with titanium dioxide, which helps to improve the chemical corrosion resistance and long-term stability of the ink.

[0013] Silane coupling agents can significantly improve the interfacial compatibility and adhesion of polymethyl methacrylate (PMMA), allowing the layered silicate minerals and ruthenium salts to better adhere to the titanium dioxide surface. Because the flat particles are more densely packed in the coating, they have better hiding power and higher gloss than spherical particles, resulting in high hiding power and high gloss for the titanium dioxide. Because the polymethyl methacrylate-layered silicate minerals are on the surface, and due to PMMA's low surface energy and non-polar properties, other substances are less likely to adhere to its surface, resulting in anti-blocking properties for the ink coating after curing. PMMA is chemically stable and can improve the weathering and chemical resistance of the ink, especially under UV irradiation, where it exhibits excellent stability. PMMA's high hardness also improves the abrasion resistance of the ink, reducing wear on the printed surface.

[0014] Preferably, in step S1, the immersion time is 10 to 18 hours; the annealing temperature is 500 to 600° C., and the time is 1 to 3 hours.

[0015] Preferably, the ruthenium salt is ruthenium trichloride.

[0016] Preferably, the titanium dioxide precursor is K2Ti4O9;

[0017] Preferably, the mass ratio of ruthenium salt to titanium dioxide precursor is 1:(18-20).

[0018] Preferably, in step S2, the modification method of the titanium dioxide-ruthenium composition includes the following steps: adding a solution to the titanium dioxide-ruthenium composition to prepare a dispersion, then adding a silane coupling agent solution to the titanium dioxide-ruthenium composition dispersion to carry out a grafting modification reaction, taking out, centrifuging, and drying to obtain a titanium dioxide-ruthenium composition modified with a silane coupling agent; the grafting modification reaction temperature is 70-80°C, and the time is 2-4 hours.

[0019] Preferably, the silane coupling agent includes at least one of γ-methacryloxypropyltrimethoxysilane (KH570), 3-aminopropyltriethoxysilane (KH550), and hexadecyltrimethoxysilane (HDTMS), more preferably KH550.

[0020] Modification with the aforementioned silane coupling agent makes titanium dioxide more easily dispersed in organic media, reducing agglomeration and thus improving its dispersibility in solvent-based inks. Silane coupling agents form a reinforced interface layer between titanium dioxide and the matrix material, facilitating stress transfer and enhancing the composite material's mechanical properties, such as tensile strength, flexural strength, and impact strength.

[0021] Preferably, the mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:(8-11).

[0022] Preferably, the mass concentration of the silane coupling agent solution is 1-2 wt%.

[0023] Preferably, in step S3, the silicate mineral dispersion is first mixed with the linker and the monomer, then heated, and then an initiator is added to carry out an in-situ polymerization reaction. After being taken out, it is filtered, washed and dried to obtain polymethyl methacrylate-layered silicate mineral; wherein the temperature of the in-situ polymerization reaction is 55-65° C., and the time is 20-28 hours.

[0024] Preferably, the mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:(8-11).

[0025] Preferably, the initiator is potassium persulfate.

[0026] Preferably, the linker is acryloyloxyethyltrimethylammonium chloride. Acryloyloxyethyltrimethylammonium chloride (AETAC) is a cationic monomer used as a linker in the synthesis of water-soluble polymers.

[0027] Layered silicate minerals are a class of silicate minerals with a layered structure. Their structural characteristic is that silicon-oxygen tetrahedra are interconnected by sharing a majority of their corner vertices (typically three-quarters of the corner vertices), forming a two-dimensional, infinitely extended layer of silicon-oxygen tetrahedra. Within these mineral layers, the oxygen atoms at the unshared corner vertices of the silicon-oxygen tetrahedra possess residual negative charges, which can bind with metal cations to form silicates. Some silicon-oxygen tetrahedra may also be replaced by aluminum-oxygen tetrahedra, creating additional negative charges that further bind with metal cations. Therefore, the present invention utilizes the cationic properties of AETAC. To attach polymer chains to the silicate surface, the silicate cations exchange with AETAC to form a stable copolymer. The monomers form polymethyl methacrylate, and this copolymer simultaneously stably attaches the polymer chains to the silicate surface, resulting in a polymethyl methacrylate-layered silicate mineral. AETAC improves the solubility and stability of polymethyl methacrylate-layered silicate minerals.

[0028] Preferably, the silicate mineral includes at least one of montmorillonite, vermiculite, muscovite, and kaolin, and more preferably montmorillonite.

[0029] Preferably, the mass ratio of the monomer to the silicate mineral is (1.1-1.3):1.

[0030] Preferably, the mass ratio of the linker to the silicate mineral is (0.8-1):1.

[0031] Preferably, in step S4, the modified titanium dioxide-ruthenium composition is first ground for 5 to 10 minutes, the polymethyl methacrylate-layered silicate mineral is dissolved in water to form a dispersion, and the modified titanium dioxide-ruthenium composition is added to the polymethyl methacrylate-layered silicate mineral dispersion and ground for 20 to 30 minutes; after grinding, the mixture is added to water to form a dispersion, and the dispersion is centrifuged at a speed of 7000 to 10000 r / min for 5 to 10 minutes, and then washed to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is titanium dioxide for printing ink; wherein the mass ratio of the modified titanium dioxide-ruthenium composition and the polymethyl methacrylate-layered silicate mineral is (10 to 20):1.

[0032] In a second aspect, the present invention provides a titanium dioxide for printing ink, which is prepared by the preparation method of the titanium dioxide for printing ink.

[0033] In a third aspect, the present invention provides an application of titanium dioxide for printing ink in the preparation of printing ink.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The modified titanium dioxide preparation method of the present invention includes: first, immersing a titanium dioxide precursor in a ruthenium salt solution, annealing and calcining, then compounding ruthenium and titanium dioxide to obtain a titanium dioxide-ruthenium composite; then, grafting the titanium dioxide-ruthenium composite with a silane coupling agent; and finally, wet-grinding polymethyl methacrylate-layered silicate mineral to coat the surface of the modified titanium dioxide-ruthenium composite. The titanium dioxide obtained by this method has high dispersibility, stability, anti-blocking properties, low abrasion, and other properties. In addition, a thin coating exhibits high hiding power and high gloss, making it suitable for ink printing. DETAILED DESCRIPTION

[0036] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] The sources of the reagents and instruments used in the embodiment are as follows:

[0038] Potassium tetratitanate whiskers (K2Ti4O9): manufactured by Shanghai Dianyang Industrial Co., Ltd.

[0039] Ruthenium trichloride: The manufacturer is Shanghai MacLean Biochemical Technology Co., Ltd., brand R817350;

[0040] Silane coupling agent:

[0041] 3-Aminopropyltriethoxysilane (KH550), manufactured by Shanghai Aladdin Biochemical Technology Co., Ltd., brand A107147;

[0042] γ-Methacryloxypropyltrimethoxysilane (KH570), manufactured by Shanghai Aladdin Biochemical Technology Co., Ltd., brand S111153;

[0043] Hexadecyltrimethoxysilane (HDTMS) was manufactured by Shanghai MacLean Biochemical Technology Co., Ltd., with the brand name H811004.

[0044] Methyl methacrylate (MMA): The manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., and the brand is M109629.

[0045] Connecting agent:

[0046] Acryloyloxyethyltrimethylammonium chloride (AETAC), manufactured by Shanghai MacLean Biochemical Technology Co., Ltd., brand A871964;

[0047] Sodium carboxymethyl cellulose (CMC), manufactured by Shanghai MacLean Biochemical Technology Co., Ltd., brand S804627.

[0048] Layered silicate minerals:

[0049] Montmorillonite, manufactured by Shanghai MacLean Biochemical Technology Co., Ltd., brand M813515;

[0050] Vermiculite: The manufacturer is Shanghai MacLean Biochemical Technology Co., Ltd., brand number V885843;

[0051] Kaolin: The manufacturer is Shanghai MacLean Biochemical Technology Co., Ltd., brand number 768524;

[0052] Potassium persulfate: The manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., and the brand name is P299302.

[0053] Linseed oil alkyd resin: manufactured by Shaoguan Derui Chemical Industry Co., Ltd., color ≤5, acid value ≤15mgKOH / g, viscosity 15000±5000MPa·s / 25℃, brand JC116;

[0054] Sodium hexametaphosphate: manufactured by Shanghai MacLean Biochemical Technology Co., Ltd., brand S817848;

[0055] Cobalt acetate tetrahydrate: manufactured by Shanghai Aladdin Biochemical Technology Co., Ltd., brand C110805;

[0056] Polydimethylsiloxane: The manufacturer is Shanghai MacLean Biochemical Technology Co., Ltd., and the brand name is P822627.

[0057] Rheometer: Manufacturer: Guangzhou Putong Experimental Analytical Instrument Co., Ltd., brand: POTOP, model: PTNI-55 / 03;

[0058] Gloss meter: purchased from Shenzhen Huaruichang Technology Co., Ltd., brand is KSJ, model is MG6-F1.

[0059] Unless otherwise specified, other materials and reagents used in the examples can be obtained from commercial sources.

[0060] Example 1

[0061] A method for preparing titanium dioxide for printing ink comprises the following steps:

[0062] S1: Immerse a titanium dioxide precursor in a ruthenium salt solution for 16 hours. The mixture is removed, centrifuged and dried, and then annealed at 550°C for 2 hours to obtain a titanium dioxide-ruthenium composite. The mass ratio of the ruthenium salt to the titanium dioxide precursor is 1:19. The titanium dioxide precursor is K2Ti4O9, and the ruthenium salt is ruthenium trichloride.

[0063] S2: Add a solution to the titanium dioxide-ruthenium composition to form a dispersion, then add a silane coupling agent solution to the titanium dioxide-ruthenium composition dispersion to carry out a grafting modification reaction. After removal, centrifugation and drying are performed to obtain a titanium dioxide-ruthenium composition modified with a silane coupling agent; the grafting modification reaction temperature is 70-80°C and the time is 2-4 hours. The silane coupling agent is 3-aminopropyltriethoxysilane (KH550). The mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:10. The mass concentration of the silane coupling agent solution is 1.5wt%.

[0064] S3: First, a silicate mineral dispersion is mixed with a linker and methyl methacrylate monomer, then heated. An initiator is added, and an in-situ polymerization reaction is carried out at 60°C for 24 hours. The mixture is removed, filtered, washed, and dried to obtain polymethyl methacrylate-layered silicate mineral. The initiator is potassium persulfate, the linker is acryloyloxyethyltrimethylammonium chloride, and the silicate mineral is montmorillonite. The mass ratio of the monomer to the silicate mineral is 1.2:1, and the mass ratio of the linker to the silicate mineral is 0.9:1.

[0065] S4 first grinds the modified titanium dioxide-ruthenium composition for 6 minutes, dissolves polymethyl methacrylate-layered silicate mineral in water to form a dispersion, adds the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral dispersion and grinds for 25 minutes; after grinding, adds water to the mixture to form a dispersion, centrifuges the dispersion at a speed of 8000r / min for 8 minutes, and then washes to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is titanium dioxide for printing ink; wherein, the mass ratio of the modified titanium dioxide-ruthenium composition and the polymethyl methacrylate-layered silicate mineral is 15:1.

[0066] Example 2

[0067] A method for preparing titanium dioxide for printing ink comprises the following steps:

[0068] S1: Immerse a titanium dioxide precursor in a ruthenium salt solution for 10 hours. The mixture is removed, centrifuged and dried, and then annealed at 500°C for 3 hours to obtain a titanium dioxide-ruthenium composite. The mass ratio of the ruthenium salt to the titanium dioxide precursor is 1:18. The titanium dioxide precursor is K2Ti4O9, and the ruthenium salt is ruthenium trichloride.

[0069] S2: Add a solution to the titanium dioxide-ruthenium composition to form a dispersion, then add a silane coupling agent solution to the titanium dioxide-ruthenium composition dispersion to carry out a grafting modification reaction. After removal, centrifugation and drying are performed to obtain a titanium dioxide-ruthenium composition modified with a silane coupling agent; the grafting modification reaction temperature is 70°C and the time is 4 hours. The silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH570). The mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:8. The mass concentration of the silane coupling agent solution is 1wt%.

[0070] S3: First, a silicate mineral dispersion is mixed with a linker and methyl methacrylate monomer, then heated. An initiator is added, and an in-situ polymerization reaction is carried out at 55°C for 28 hours. The mixture is removed, filtered, washed, and dried to obtain polymethyl methacrylate-layered silicate mineral. The initiator is potassium persulfate, the linker is acryloyloxyethyltrimethylammonium chloride, and the silicate mineral is vermiculite. The mass ratio of the monomer to the silicate mineral is 1.1:1, and the mass ratio of the linker to the silicate mineral is 0.8:1.

[0071] S4 first grinds the modified titanium dioxide-ruthenium composition for 5 minutes, dissolves polymethyl methacrylate-layered silicate mineral in water to form a dispersion, adds the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral dispersion and grinds for 20 minutes; after grinding, adds water to the mixture to form a dispersion, centrifuges the dispersion at a speed of 7000 r / min for 10 minutes, and then washes to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is titanium dioxide for printing ink; wherein, the mass ratio of the modified titanium dioxide-ruthenium composition and the polymethyl methacrylate-layered silicate mineral is 10:1.

[0072] Example 3

[0073] A method for preparing titanium dioxide for printing ink comprises the following steps:

[0074] S1: Immerse a titanium dioxide precursor in a ruthenium salt solution for 18 hours. The mixture is removed, centrifuged and dried, and then annealed at 600°C for 1 hour to obtain a titanium dioxide-ruthenium composite. The mass ratio of the ruthenium salt to the titanium dioxide precursor is 1:20. The titanium dioxide precursor is K2Ti4O9, and the ruthenium salt is ruthenium trichloride.

[0075] S2: Adding a solution to a titanium dioxide-ruthenium composition to form a dispersion, then adding a silane coupling agent solution to the titanium dioxide-ruthenium composition dispersion to carry out a grafting modification reaction. After removal, centrifugation, and drying, a titanium dioxide-ruthenium composition modified with a silane coupling agent is obtained. The grafting modification reaction is carried out at a temperature of 80°C and for a time of 2 hours. The silane coupling agent is hexadecyltrimethoxysilane (HDTMS). The mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:11. The mass concentration of the silane coupling agent solution is 2 wt%.

[0076] S3: First, a silicate mineral dispersion is mixed with a linker and a monomer, then heated. An initiator is added, and an in-situ polymerization reaction is carried out at 65°C for 20 hours. The mixture is removed, filtered, washed, and dried to obtain polymethyl methacrylate-layered silicate mineral. The initiator is potassium persulfate. The linker is acryloyloxyethyltrimethylammonium chloride. The silicate mineral is kaolin. The mass ratio of the monomer to the silicate mineral is 1.3:1. The mass ratio of the linker to the silicate mineral is 1:1.

[0077] S4 first grinds the modified titanium dioxide-ruthenium composition for 10 minutes, dissolves polymethyl methacrylate-layered silicate mineral in water to form a dispersion, adds the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral dispersion and grinds for 30 minutes; after grinding, adds water to the mixture to form a dispersion, centrifuges the dispersion at a speed of 10,000 r / min for 5 minutes, and then washes to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is titanium dioxide for printing ink; wherein, the mass ratio of the modified titanium dioxide-ruthenium composition and the polymethyl methacrylate-layered silicate mineral is 20:1.

[0078] Example 4

[0079] The difference between Example 4 and Example 1 is that the linker in Example 4 is sodium carboxymethyl cellulose (CMC).

[0080] Example 5

[0081] The difference between Example 5 and Example 1 is that the silane coupling agent in Example 5 is γ-methacryloxypropyltrimethoxysilane (KH570).

[0082] Example 6

[0083] The difference between Example 6 and Example 1 is that the silane coupling agent in Example 6 is hexadecyltrimethoxysilane (HDTMS).

[0084] Example 7

[0085] The difference between Example 7 and Example 1 is that in step S4 of Example 7, the mass ratio of the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral is 9:1.

[0086] Example 8

[0087] The difference between Example 8 and Example 1 is that in step S4 of Example 8, the mass ratio of the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral is 22:1.

[0088] Example 9

[0089] The difference between Example 9 and Example 1 is that the mass ratio of ruthenium trichloride to titanium dioxide precursor in Example 9 is 1:17.

[0090] Example 10

[0091] The difference between Example 10 and Example 1 is that the mass ratio of ruthenium trichloride to titanium dioxide precursor in Example 9 is 1:21.

[0092] Comparative Example 1

[0093] The difference between Comparative Example 1 and Example 1 is that the titanium dioxide-ruthenium composition of Comparative Example 1 is not modified by a silane coupling agent.

[0094] Comparative Example 2

[0095] The difference between Comparative Example 2 and Example 1 is that the montmorillonite in Comparative Example 2 is not modified with polymethyl methacrylate.

[0096] Comparative Example 3

[0097] The difference between Comparative Example 3 and Example 1 is that in step S3 of Comparative Example 3, no linking agent is added.

[0098] Comparative Example 4

[0099] The difference between Comparative Example 4 and Example 1 is that in step S4 of Comparative Example 4, polymethyl methacrylate is directly added without adding montmorillonite.

[0100] Comparative Example 5

[0101] The difference between Comparative Example 5 and Example 1 is that no ruthenium trichloride solution is added in step S1 of Comparative Example 6, that is, titanium dioxide is not complexed with ruthenium.

[0102] Comparative Example 6

[0103] The difference between Comparative Example 6 and Example 1 is that the montmorillonite in Comparative Example 6 is replaced by silicon dioxide.

[0104] Application Examples 1 to 10 and Comparative Application Examples 1 to 8

[0105] Application Examples 1 to 10 and Comparative Application Examples 1 to 6 are application examples of Examples 1 to 10 and Comparative Examples 1 to 6, respectively, that is, the modified titanium dioxide of Examples 1 to 10 and Comparative Examples 1 to 6 are used to make inks, respectively, while Comparative Application Example 7 is a blank control group that directly uses unmodified titanium dioxide.

[0106] The inks of Application Examples 1 to 10 and Comparative Application Examples 1 to 7 comprise the following components in percentage: 30% titanium dioxide, 35% alkyd resin, 30% toluene, and 1% cobalt drier, wherein the cobalt drier is cobalt acetate tetrahydrate.

[0107] The ink of comparative application example 8 includes the following components in percentage: 30% titanium dioxide, 35% alkyd resin, 24% toluene, 1% cobalt drying agent, 3% dispersant, 1% leveling agent and 2% microcrystalline wax in each group; wherein, the dispersant is sodium hexametaphosphate, the cobalt drying agent is cobalt acetate tetrahydrate, and the leveling agent is polydimethylsiloxane.

[0108] The preparation method of each group of inks comprises the following steps:

[0109] Add titanium dioxide and half the solvent to a dispersing device and stir at high speed until a uniform slurry is formed. Then add the binder and continue stirring to thoroughly mix and disperse the resin and pigment. Add the remaining solvent and other additives. Grind further on a three-roll mill or sand mill until the desired fineness and uniformity are achieved. Filter to remove any impurities or aggregates, yielding the inks for Application Examples 1-10 and Comparative Application Examples 1-8, yielding 18 sets of samples.

[0110] In actual production, the ink formula can be adjusted to adjust product performance.

[0111] Performance Testing

[0112] The ink samples of Application Examples 1 to 10 and Comparative Application Examples 1 to 8 were subjected to the following tests:

[0113] 1. Fineness test

[0114] According to the national standard GB / T13217.3-2022, take 0.5g of ink and use a scraper fineness meter to scrape it from top to bottom. The fineness is expressed in microns (μm). The smaller the fineness, the better the dispersibility.

[0115] 2. Rheological properties test

[0116] Place the test ink into two iron boxes, each containing at least 15g of ink. Remove any bubbles, seal with cellophane, label, and then close the boxes. Place the boxes in a 75-80°C thermostat and a -15-20°C freezer for 72 hours. Remove and store at room temperature. After storing at room temperature for at least three hours, measure the fluidity of the ink and compare its fluidity with that of the ink that was not heated or frozen.

[0117] Characterize ink fluidity according to the national standard GB / T14624.3-2008. Take 1 mL of ink and place it in the fluidity tester. Cover with a glass slide and place a weight. Read the result after 15 minutes. Use a ruler to measure the sample and expand the diameter. The diameter indicates the fluidity.

[0118] 3. Gloss test

[0119] Take 0.5g of ink and drop it on the scraping paper. Place the scraper on the applied ink sample, make the scraper perpendicular to the scraping paper, scrape it from top to bottom into a thin layer, let it dry, and measure it with a gloss meter.

[0120] 4. Friction resistance test

[0121] Using a six-color gravure printing press, each ink group is printed onto the tipping paper surface via a gravure roller. The paper is then cut to the desired width to produce tipping paper samples. A 50.0mm x 230.0mm test sample is mounted on a friction table and rubbed 15 times back and forth using a friction tester. The printed surface is observed for color fading. The "Color Fastness Fading Scale" can be used for grading. The section with the greatest rubbing damage can be placed side by side with the unrubbed section. When the color difference between the rubbing-damaged section and the unrubbed section corresponds to a specific grade on the "Color Fastness Fading Scale," the paper is graded at that grade. Grade 5 is the best, and grade 1 is the worst. Grades between these two grades are considered intermediate, such as 2-3, meaning slightly better than 2 and slightly worse than 3.

[0122] Table 1 Performance data of each group of ink samples

[0123]

[0124] As can be seen from Table 1, the only variable in each group of inks is titanium dioxide, which indicates that the titanium dioxide in the ink samples of Application Examples 1 to 3 has good dispersibility, stability, glossiness and wear resistance.

[0125] Since no additives such as dispersants, leveling agents, and stabilizers were added to the ink of Comparative Application Example 7, its ink performance was poor and did not meet the national standards for ink fineness less than 20 μm and fluidity within the range of 28 to 36 mm. The ink of Comparative Application Example 8, although additives such as dispersants and leveling agents were added, its gloss, dispersibility, stability, and wear resistance were significantly lower than those of the ink of Application Example 1, indicating that the addition of the modified titanium dioxide of the present invention can effectively improve the performance of the ink.

[0126] In Application Example 4, the linker used in the titanium dioxide preparation process is sodium carboxymethyl cellulose (CMC). Because CMC has poor dispersibility, good hydrophilicity, and is prone to clumping, it results in poor adhesion between PMMA and montmorillonite, affecting the dispersibility, gloss, and mechanical properties of the titanium dioxide. Furthermore, CMC has thermal stability flaws. Prolonged heating above 80°C may denature the colloid, resulting in a significant decrease in viscosity and performance, thus affecting the high-temperature stability of the ink. In contrast, in Application Example 3, no linker was added, making it difficult for PMMA and montmorillonite to form a stable complex, which significantly affects the performance of the ink.

[0127] The silane coupling agents used in Application Examples 5 and 6 were KH570 and HDTMS, respectively. The inks' leveling, fineness, and stability were all lower than those in Application Example 1. This is because KH550 in Application Example 1 has more amino functional groups than the other two agents, providing additional reactivity and diverse chemical bonding methods, resulting in a tighter bond with PMMA and improving ink performance.

[0128] The amount of modified titanium dioxide-ruthenium composition added to the ink of Application Example 7 was too small, while the amount of modified titanium dioxide-ruthenium composition added in Application Example 8 was too high, resulting in reduced dispersibility and stability. This indicates that the preferred range is a mass ratio of the modified titanium dioxide-ruthenium composition to polymethyl methacrylate-layered silicate mineral of (10-20):1. Similarly, the mass ratio of ruthenium trichloride to titanium dioxide precursor in Application Examples 9 and 10 was not within the range of 1:(18-20), resulting in reduced ink performance.

[0129] In contrast, the titanium dioxide-ruthenium composition in the modified titanium dioxide of Application Example 1 is not modified with a silane coupling agent, and the dispersibility, stability and wear resistance of the ink are greatly reduced. This is because the silane coupling agent can significantly improve the interfacial compatibility and adhesion of polymethyl methacrylate (PMMA), thereby enabling the layered silicate minerals and ruthenium salts to better adhere to the titanium dioxide surface.

[0130] In contrast, the montmorillonite in the modified titanium dioxide of Application Example 2, which is not modified with polymethyl methacrylate, exhibits significantly reduced stability and abrasion resistance. This is because PMMA is chemically stable, which improves the weather and chemical resistance of the ink, especially under UV irradiation. PMMA's high hardness also improves the abrasion resistance of the ink, reducing wear on the printed surface.

[0131] Comparatively, the modified titanium dioxide in Application Example 4, which lacks montmorillonite, exhibits significantly lower gloss. This is because montmorillonite's flat particle structure provides better hiding power and higher gloss than spherical particles, thereby enhancing the high hiding power and gloss of the titanium dioxide. Furthermore, the layered structure of montmorillonite acts as a stabilizer, improving the ink's storage stability and reducing pigment settling and delamination.

[0132] In contrast, in Application Example 5, the modified titanium dioxide is not added with ruthenium, and its stability is significantly reduced. This is because ruthenium can provide the ink with good room temperature stability, low temperature stability and high temperature stability, and can also improve the wear resistance of the ink.

[0133] In the modified titanium dioxide of comparative application example 6, silicon dioxide replaces montmorillonite, and its dispersibility and stability are slightly reduced, but the glossiness and wear resistance of the ink are significantly reduced. Therefore, montmorillonite can improve the glossiness and wear resistance of the ink.

[0134] In summary, the titanium dioxide obtained by the above method has high dispersibility, stability, anti-adhesion, low abrasion and other properties, and a thin coating has high hiding and high gloss properties, which is suitable for ink printing.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing titanium dioxide for printing ink, characterized in that: The following steps are involved: S1: immersing a titanium dioxide precursor in a ruthenium salt solution, taking out the mixture, centrifugally drying it, and then annealing it to obtain a titanium dioxide-ruthenium composition; wherein the ruthenium salt is ruthenium trichloride, the titanium dioxide precursor is K2Ti4O9, and the mass ratio of the ruthenium salt to the titanium dioxide precursor is 1:(18-20); S2: surface-modifying the titanium dioxide-ruthenium composition with a silane coupling agent to obtain a modified titanium dioxide-ruthenium composition; S3: subjecting the silicate mineral dispersion to an in situ polymerization reaction in the presence of an initiator, methyl methacrylate monomer, and a linker to obtain polymethyl methacrylate-layered silicate mineral; the linker is acryloyloxyethyltrimethylammonium chloride; S4: adding the modified titanium dioxide-ruthenium composition to a dispersion of polymethyl methacrylate-layered silicate mineral and grinding to obtain a mixture; then preparing the mixture into a dispersion; centrifuging the solid and drying it to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is the titanium dioxide for printing ink.

2. The method for preparing titanium dioxide for printing ink according to claim 1, wherein: In the step S1, the immersion time is 10-18 hours; the annealing temperature is 500-600° C., and the time is 1-3 hours.

3. The method for preparing titanium dioxide for printing ink according to claim 1, wherein: In step S2, the modification method of the titanium dioxide-ruthenium composition includes the following steps: adding a solution to the titanium dioxide-ruthenium composition to prepare a dispersion, then adding a silane coupling agent solution to the titanium dioxide-ruthenium composition dispersion to carry out a grafting modification reaction, and after taking out, centrifuging and drying to obtain a titanium dioxide-ruthenium composition modified with a silane coupling agent; the grafting modification reaction temperature is 70-80°C and the time is 2-4 hours.

4. The method for preparing titanium dioxide for printing ink according to claim 1 or 3, wherein: In step S2, at least one of the following (I) to (III) is selected: (I) the silane coupling agent includes at least one of γ-methacryloxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and hexadecyltrimethoxysilane; (II) the mass ratio of the silane coupling agent to the titanium dioxide-ruthenium composition is 1:(8-11); (III) The mass concentration of the silane coupling agent solution is 1-2 wt %.

5. The method for preparing titanium dioxide for printing ink according to claim 1, wherein: In step S3, the silicate mineral dispersion is first mixed with a linker and a monomer, then heated, and then an initiator is added to carry out an in-situ polymerization reaction. After being taken out, it is filtered, washed, and dried to obtain polymethyl methacrylate-layered silicate mineral; wherein the temperature of the in-situ polymerization reaction is 55-65° C., and the time is 20-28 hours.

6. The method for preparing titanium dioxide for printing ink according to claim 1 or 5, wherein: In step S3, at least one of the following (I) to (IV) is selected: (I) The initiator is potassium persulfate; (II) The silicate mineral includes at least one of montmorillonite, vermiculite, muscovite, and kaolin. (III) the mass ratio of the monomer to the silicate mineral is (1.1-1.3):1; (IV) The mass ratio of the linker to the silicate mineral is (0.8~1):

1.

7. The method for preparing titanium dioxide for printing ink according to claim 1, wherein: In step S4, the modified titanium dioxide-ruthenium composition is first ground for 5 to 10 minutes, polymethyl methacrylate-layered silicate mineral is dissolved in water to form a dispersion, and the modified titanium dioxide-ruthenium composition is added to the polymethyl methacrylate-layered silicate mineral dispersion and ground for 20 to 30 minutes; after grinding, the mixture is added to water to form a dispersion, and the dispersion is centrifuged at a speed of 7000 to 10000 r / min for 5 to 10 minutes, and then washed to obtain a titanium dioxide-ruthenium composition coated with polymethyl methacrylate-layered silicate mineral, which is titanium dioxide for printing ink; wherein the mass ratio of the modified titanium dioxide-ruthenium composition to the polymethyl methacrylate-layered silicate mineral is (10 to 20):

1.

8. A titanium dioxide for printing ink, characterized in that: The titanium dioxide for printing ink is prepared by the preparation method of titanium dioxide for printing ink according to any one of claims 1 to 7.

9. Use of the titanium dioxide for printing ink according to any one of claims 1 to 7 in the preparation of printing ink.

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