Ultra-white high-solid white ink as well as preparation method and application thereof

Abstract

The invention discloses ultra-white high-solid white ink as well as a preparation method and application thereof, and belongs to the technical field of ink. The ink comprises the following components in parts by weight: 30-40 parts of high-purity titanium dioxide subjected to surface treatment, 35-45 parts of an acrylic resin and epoxy resin blending binder, 15-25 parts of an ester-alcohol composite solvent and 10-20 parts of a functional additive combination. The preparation method comprises the key processes of pre-dispersion, resin blending, gradient feeding, solvent blending, three-roller grinding and the like, and the grinding fineness is controlled to be smaller than or equal to 10 microns. By optimizing the component synergistic effect and process control, the technical bottlenecks of insufficient whiteness, low solid content, poor stability and the like of the traditional white ink are solved, and the white ink has the characteristics of efficient production and environmental friendliness.

Description

Technical Field

[0001] The present invention relates to the technical field of printing inks, and in particular to an ultra-white high-solid white ink and a preparation method and application thereof. Background Art

[0002] White ink is a common type of ink in the printing industry, widely used in packaging printing, decorative printing, and other fields. Whiteness and solids content are two important performance indicators for white ink. A higher whiteness can produce a brighter, purer white effect on printed products, enhancing the product's visual appeal. A high solids content, on the other hand, reduces ink usage for the same print thickness, improving production efficiency while also improving the ink's drying properties and printability.

[0003] However, the white inks currently on the market still have certain deficiencies in terms of whiteness and solids content. Some white inks lack sufficient whiteness to meet the high whiteness requirements of high-end products. Other inks, despite having a high solids content, are prone to problems during printing, such as poor leveling and excessively fast or slow drying, which impacts print quality and production efficiency. Furthermore, the weather and chemical resistance of some white inks need improvement, and they are prone to discoloration and fading over time. Therefore, the development of an ultra-white, high-solids, and well-balanced white ink is of great practical significance. Summary of the Invention

[0004] The present invention aims to provide an ultra-white high-solid white ink and a preparation method and application thereof.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: an ultra-white high-solid white ink, comprising the following components, in parts by weight: 30-40 parts of a white pigment, which is a high-purity titanium dioxide with an average particle size of 0.2-0.4 μm; 35-45 parts of a resin binder, which is composed of an acrylic resin and an epoxy resin in a mass ratio of 1:0.7-1:1; 15-25 parts of a solvent, which comprises an ester solvent and an alcohol solvent, wherein the ester solvent accounts for 60-80% of the total solvent amount and the alcohol solvent accounts for 20-40%; and 10-20 parts of an additive, which includes a dispersant, a leveling agent, a defoaming agent, a whitening agent, an anti-settling agent and a curing agent.

[0006] As a preferred technical solution of the present invention, the ester solvent is a mixture of butyl acetate and ethylene glycol butyl ether acetate, and the mass ratio of the two is 1:0.5-1:1; the alcohol solvent is a mixture of n-butanol and isopropanol, and the mass ratio of the two is 1:0.5-1:1.

[0007] As a preferred technical solution of the present invention, the dispersant is a polymer dispersant containing an anchoring group and a solvent-friendly segment, and the anchoring group is selected from at least one of a phosphate group, a carboxylic acid group or an amine group.

[0008] A method for preparing an ultra-white high-solid white ink comprises the following steps: Step a, pre-dispersion: mix the white pigment with part of the solvent (the initial amount of solvent added is 45%-55% of the total solvent), and stir at 800-1200 r / min for 15-25 minutes to form a pigment slurry; Step b, resin mixing: add acrylic resin and epoxy resin to the pigment slurry, stir at 400-600 r / min for 20-30 minutes to fully mix the resin and pigment slurry; Step c, adding additives: adding dispersant, leveling agent, defoamer, brightener and anti-settling agent in sequence, stirring at 300-500 r / min for 10-15 minutes to evenly disperse the additives in the ink; Step d, solvent adjustment: adding the remaining solvent according to the viscosity and solid content requirements of the ink, and replenishing the remaining solvent until the ink reaches a viscosity range suitable for the printing process; Step e, grinding and filtering: grinding with a three-roll mill to a fineness of ≤10 μm, and filtering through a 200-300 mesh filter.

[0009] A method for preparing an ultra-white high-solid white ink, wherein the grinding fineness in step e is controlled to be 5-8 μm.

[0010] The invention discloses an application of an ultra-white high-solid white ink, which is suitable for packaging printing or decorative printing, and is specifically used for printing on paper, plastic or metal substrates.

[0011] Compared with the prior art, the present invention has the following beneficial effects: Ultra-white effect: The use of high-purity titanium dioxide and brighteners gives the ink an extremely high whiteness, which can meet the demand for ultra-white effects of high-end products and improve the visual quality of printed products.

[0012] High solid content: Through the rational selection of resin binders and solvent systems, a high solid content is achieved while ensuring good printability. High solid content not only reduces ink usage and production costs, but also improves production efficiency and shortens drying time.

[0013] Good printability: The ink has moderate viscosity and drying speed, good leveling properties, and can be smoothly transferred and coated on various printing equipment. The surface of the printed ink film is flat and smooth, without defects such as pinholes, bubbles, and orange peel, ensuring printing quality.

[0014] Excellent physical and chemical properties: The blending system of acrylic resin and epoxy resin and the reasonable combination of additives give the ink good adhesion, hardness, abrasion resistance, weather resistance and chemical resistance, which can adapt to different usage environments and requirements and extend the service life of printed products.

[0015] Environmental performance: The solvents and additives used in the present invention all meet environmental protection requirements, reduce harm to the environment and human body, and have good environmental performance. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0017] The present invention discloses an ultra-white high-solid white ink, which comprises the following components in parts by weight: 30-40 parts of white pigment, which is high-purity titanium dioxide with an average particle size of 0.2-0.4μm, has extremely high refractive index and hiding power, and can give the ink excellent whiteness and hiding performance; the models of the auxiliary components in this embodiment are: dispersant BYK-190, leveling agent Dow Corning DC-29, defoaming agent TFGO830, anti-settling agent Cabot M-5 and curing agent Covestro 305. In this embodiment, titanium dioxide is used as the core pigment in the ink. When its average particle size is controlled at 0.2-0.4μm and has high purity, it can significantly improve the whiteness and hiding performance of the ink. The main reasons are as follows: Refractive index characteristics: The refractive index of titanium dioxide (rutile TiO2 is about 2.71) is much higher than that of other components in the ink (such as resin ≈1.5, solvent ≈1.3). This high refractive index causes light to scatter strongly within the ink layer, rather than being directly penetrated or absorbed, thereby enhancing hiding power. Mie scattering effect: When the titanium dioxide particle size approaches the wavelength of visible light (400-700nm, or 0.4-0.7μm), light scattering efficiency reaches its maximum. The particle size range of 0.2-0.4μm falls within the range of half to full wavelength of visible light, maximizing light reflection and scattering, significantly improving hiding power. Impurity control: High-purity titanium dioxide (TiO2 content ≥98%) reduces the presence of metallic impurities such as iron and chromium, preventing yellowing or loss of whiteness due to light absorption by impurities.

[0018] 35-45 parts of a resin binder, composed of acrylic resin and epoxy resin in a mass ratio of 1:0.7-1:1. In this embodiment, the acrylic resin has good film-forming properties, flexibility, and gloss, while the epoxy resin has excellent adhesion and chemical resistance. The blend of the two fully utilizes their respective advantages, resulting in an ink with excellent printability and physical and chemical properties.

[0019] 15-25 parts of solvent, including ester solvent and alcohol solvent, of which ester solvent accounts for 60-80% of the total solvent amount and alcohol solvent accounts for 20-40%; this mixed solvent system has good solubility and volatility, and can ensure a high solid content of the ink while making the ink have a suitable viscosity and drying speed.

[0020] 10-20 parts of additives, including dispersants, leveling agents, defoaming agents, brighteners, anti-settling agents and curing agents. Dispersants can effectively reduce the surface tension of white pigments, making them evenly dispersed in the ink and preventing agglomeration; leveling agents can improve the leveling properties of inks, making the surface of the printed ink film smoother; defoaming agents are used to eliminate bubbles generated during the preparation and printing of inks; brighteners can further improve the whiteness of inks, making them ultra-white; anti-settling agents can prevent white pigments from settling during storage, ensuring the stability of the ink; curing agents are used to cause epoxy resins to undergo cross-linking and curing reactions, thereby improving the hardness and wear resistance of the ink film.

[0021] The ester solvent is a mixture of butyl acetate and ethylene glycol butyl ether acetate, and the mass ratio of the two is 1:0.5-1:1; the alcohol solvent is a mixture of n-butanol and isopropanol, and the mass ratio of the two is 1:0.5-1:1.

[0022] The dispersant is a polymer dispersant containing an anchoring group and a solvent-friendly segment, and the anchoring group is selected from at least one of a phosphate group, a carboxylic acid group or an amine group. Typical dispersants include but are not limited to BYK-190, EFKA-4010, etc.

[0023] A method for preparing an ultra-white high-solid white ink comprises the following steps: Step a, pre-dispersion: mix the white pigment with part of the solvent and stir at 800-1200 r / min for 15-25 minutes to form a pigment slurry; Step b, resin mixing: add acrylic resin and epoxy resin to the pigment slurry, stir at 400-600 r / min for 20-30 minutes to fully mix the resin and pigment slurry; Step c, adding additives: adding dispersant, leveling agent, defoamer, brightener and anti-settling agent in sequence, stirring at 300-500 r / min for 10-15 minutes to evenly disperse the additives in the ink; Step d, solvent adjustment: according to the viscosity and solid content requirements of the ink, add the remaining solvent, control the amount by yourself, and add the remaining solvent to make the ink reach a viscosity range suitable for the printing process; Step e, grinding and filtering: grinding with a three-roll mill to a fineness of ≤10 μm, and filtering through a 200-300 mesh filter.

[0024] In step e of this embodiment, the grinding fineness is controlled to be 5-8 μm.

[0025] The invention discloses an application of an ultra-white high-solid white ink, which is suitable for packaging printing or decorative printing, and is specifically used for printing on paper, plastic or metal substrates.

[0026] The present invention has the following characteristics: Ultra-white effect: The use of high-purity titanium dioxide and brighteners gives the ink an extremely high whiteness, which can meet the demand for ultra-white effects of high-end products and improve the visual quality of printed products.

[0027] High solid content: Through the rational selection of resin binders and solvent systems, a high solid content is achieved while ensuring good printability. High solid content not only reduces ink usage and production costs, but also improves production efficiency and shortens drying time.

[0028] Good printability: The ink has moderate viscosity and drying speed, good leveling properties, and can be smoothly transferred and coated on various printing equipment. The surface of the printed ink film is flat and smooth, without defects such as pinholes, bubbles, and orange peel, ensuring printing quality.

[0029] Excellent physical and chemical properties: The blending system of acrylic resin and epoxy resin and the reasonable combination of additives give the ink good adhesion, hardness, abrasion resistance, weather resistance and chemical resistance, which can adapt to different usage environments and requirements and extend the service life of printed products.

[0030] Environmental performance: The solvents and additives used in the present invention all meet environmental protection requirements, reduce harm to the environment and human body, and have good environmental performance. Example 1

[0031] Ink composition: by weight, 32 parts of titanium dioxide, 20 parts of acrylic resin, 20 parts of epoxy resin, 10 parts of butyl acetate, 6 parts of ethylene glycol butyl ether acetate, 4 parts of n-butanol, 2 parts of isopropyl alcohol, 3 parts of dispersant, 2 parts of leveling agent, 1 part of defoaming agent, 2 parts of brightener, 2 parts of anti-settling agent, and 2 parts of curing agent.

[0032] Preparation method: Titanium dioxide is added to a mixed solvent of 6 parts butyl acetate, 2 parts n-butanol, and 2 parts isopropanol. Stir at 1000 rpm for 20 minutes to form a pigment slurry. Acrylic resin and epoxy resin are then added and stirred at 500 rpm for 25 minutes. Dispersant, leveling agent, defoamer, brightener, and anti-settling agent are then added in sequence and stirred at 400 rpm for 12 minutes. A curing agent is added before printing and stirred until uniform. The remaining solvent (4 parts butyl acetate, 4 parts ethylene glycol butyl ether acetate, and 2 parts n-butanol) is added to adjust the ink viscosity. The mixture is ground using a three-roll mill to a fineness of 8 μm. Finally, it is filtered through a 250-mesh filter to obtain an ultra-white, high-solids white ink. The test data in Example 1 are the best available data. Commercially available inks for Example 1 include Flint Group's NovaTec™ series solvent-based white inks, while commercially available inks for Example 2 include Siegwerk's Ecokett® general-purpose white inks.

[0033] The test data table after printing is as follows: Example 2

[0034] Ink composition: by weight, 35 parts of titanium dioxide, 22 parts of acrylic resin, 20 parts of epoxy resin, 12 parts of butyl acetate, 8 parts of ethylene glycol butyl ether acetate, 3 parts of n-butanol, 2 parts of isopropyl alcohol, 3.5 parts of dispersant, 2.5 parts of leveling agent, 1.5 parts of defoaming agent, 2.5 parts of brightener, 2.5 parts of anti-settling agent, and 2.5 parts of curing agent.

[0035] Preparation method: Similar to Example 1, except for the amounts of components and stirring parameters. Titanium dioxide was added to a mixed solvent of 8 parts butyl acetate, 3 parts n-butanol, and 2 parts isopropanol, and stirred at 800 rpm for 25 minutes. After adding the resin, the stirring speed was increased to 400 rpm for 30 minutes. After adding the additive, the stirring speed was increased to 300 rpm for 15 minutes. The mixture was then ground using a three-roll mill to a fineness of 7 μm. Finally, it was filtered through a 200-mesh filter.

[0036] The test data of Example 2 and Example 1 have little deviation, so no additional experimental data table is provided. Example 1 is the best data.

[0037] Example 3: Ink composition: by weight, 38 parts of titanium dioxide, 25 parts of acrylic resin, 18 parts of epoxy resin, 14 parts of butyl acetate, 10 parts of ethylene glycol butyl ether acetate, 4 parts of n-butanol, 3 parts of isopropyl alcohol, 4 parts of dispersant, 3 parts of leveling agent, 2 parts of defoaming agent, 3 parts of brightener, 3 parts of anti-settling agent, and 3 parts of curing agent.

[0038] Preparation method: Add titanium dioxide to a mixed solvent of 10 parts of butyl acetate, 4 parts of n-butanol and 3 parts of isopropanol, and stir at a stirring speed of 1200r / min for 15 minutes; after adding the resin, stir at a speed of 600r / min and stir for 20 minutes; after adding the additive, stir at a speed of 500r / min and stir for 10 minutes; grind with a three-roll mill, and control the grinding fineness to 6μm; finally filter through a 300-mesh filter.

[0039] The test data of the third embodiment is not much different from that of the first embodiment, so no additional experimental data table is provided.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An ultra-white high-solid white ink, characterized by: The invention comprises the following components in parts by weight: 30-40 parts of white pigment, which is high-purity titanium dioxide with an average particle size of 0.2-0.4 μm; 35-45 parts of resin binder, which is composed of acrylic resin and epoxy resin in a mass ratio of 1:0.7-1:1; 15-25 parts of solvent, which comprises ester solvent and alcohol solvent, of which ester solvent accounts for 60-80% of the total solvent amount and alcohol solvent accounts for 20-40%; 10-20 parts of additives, which include dispersant, leveling agent, defoaming agent, whitening agent, anti-settling agent and curing agent.

2. The ultra-white high-solid white ink according to claim 1, characterized in that: The ester solvent is a mixture of butyl acetate and ethylene glycol butyl ether acetate, and the mass ratio of the two is 1:0.5-1:1; the alcohol solvent is a mixture of n-butanol and isopropanol, and the mass ratio of the two is 1:0.5-1:

1.

3. The ultra-white high-solid white ink according to claim 2, characterized in that: The dispersant is a polymer dispersant containing an anchoring group and a solvent-friendly segment, and the anchoring group is selected from at least one of a phosphate group, a carboxylic acid group or an amine group.

4. A method for preparing the ultra-white high-solid white ink according to any one of claims 1 to 3, characterized in that The following steps are involved: Step a, pre-dispersion: mix the white pigment with part of the solvent and stir at 800-1200 r / min for 15-25 minutes to form a pigment slurry; Step b, resin mixing: add acrylic resin and epoxy resin to the pigment slurry, stir at 400-600 r / min for 20-30 minutes to fully mix the resin and pigment slurry; Step c, adding additives: adding dispersant, leveling agent, defoamer, brightener and anti-settling agent in sequence, stirring at 300-500 r / min for 10-15 minutes to evenly disperse the additives in the ink; Step d, solvent adjustment: adding the remaining solvent according to the viscosity and solid content requirements of the ink, and replenishing the remaining solvent until the ink reaches a viscosity range suitable for the printing process; Step e, grinding and filtering: grinding with a three-roll mill to a fineness of ≤10 μm, and filtering through a 200-300 mesh filter.

5. The preparation method according to claim 4, characterized in that: The grinding fineness in step e is controlled to be 5-8 μm.

6. The preparation method according to claim 4, characterized in that: The initial addition amount of solvent is 45%-55% of the total solvent.

7. A use of the ultra-white high-solid white ink according to any one of claims 1 to 6, characterized in that: The ink is suitable for the field of packaging printing or decorative printing.

8. The use according to claim 7, characterized in that: The ink is used in printing processes on paper, plastic or metal substrates.

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