Magnetic ceramic colorant as printing consumables and preparation method thereof

Abstract

The present invention discloses a magnetic ceramic pigment for use as a printing consumable. The pigment comprises at least three layers, comprising a core of soft magnetic material particles, a protective cosmetic layer in the middle, and a ceramic pigment as the outer layer. Furthermore, a method for preparing the magnetic ceramic pigment for use as a printing consumable is disclosed. The ceramic pigment exhibits magnetic properties, a pure color, and excellent solid-state fluidity. As a printing consumable, the pigment is suitable for use in ceramic laser printing systems that utilize magnetic forces as a migration force. This migration force provides improved controllability, effectively overcoming the technical shortcomings of current ceramic laser printing systems based on electrostatic adsorption.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic laser printing, in particular to a magnetic ceramic colorant used as a printing consumable material and using magnetic force as a migration force, and a preparation method thereof. Background Art

[0002] Ceramic inkjet printing, with its contactless, plate-free nature, has become a mainstream ceramic decoration technology. However, the ceramic ink used in this technology is a thermodynamically unstable suspension system with limited kinetic stability, making it prone to nozzle clogging. To address this, ceramic laser printing technology has been developed, drawing on the principles of office laser printers. Ceramic laser printers use solid ceramic powder as printing consumables, effectively addressing the current inkjet printing ink instability and clogging issues. Current ceramic laser printing still relies on electrostatic adsorption. However, unlike office laser printing, the toner used in office laser printing has a diameter of 5-10 μm, a nearly spherical shape, and weak inter-particle forces, resulting in excellent solid-state flowability. Furthermore, the toner has a low density and good conductivity, allowing electrostatic transfer even with larger toner particles. However, the ceramic pigment used in ceramic laser printing has a much higher density than toner. Therefore, for effective adsorption of the ceramic pigment under the same electrostatic strength conditions, the particle size must be reduced to nanometers or the electrostatic strength must be increased by 5-10 times. Ceramic pigments with nanometer-scale particle sizes are not only expensive to prepare, but also exhibit inconsistent coloration compared to macroscopic ceramic pigments of the same composition. More importantly, they can easily dissolve into the glaze and lose their color during actual use. Furthermore, ceramic pigments typically have poor electrical conductivity, making it difficult to increase their charge strength. Therefore, if magnetic effects were used instead of electrostatic effects as the migration force for transferring ceramic pigment powder, a magnetic ceramic laser printer could be developed. This could control the migration of the powder by adjusting the applied magnetic field strength, thereby overcoming the technical limitations of current ceramic laser printing methods based on electrostatic adsorption. Therefore, it is necessary to provide a magnetic ceramic pigment as a printing consumable. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art by providing a magnetic ceramic pigment with pure color and good solid-state fluidity, suitable for use as a printing consumable in ceramic laser printing systems that utilize magnetic forces as a migration force. Another object of the present invention is to provide a method for preparing the magnetic ceramic pigment used as a printing consumable.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] The present invention provides a magnetic ceramic pigment for use as a printing consumable, comprising at least three layers: a core of soft magnetic material particles, a middle layer of a protective cosmetic layer, and an outer layer of ceramic pigment. Furthermore, the ratio of the core radius: protective cosmetic layer thickness: outer ceramic pigment thickness is 1:0.01-2:2-6.

[0006] According to actual needs, in order to further improve the fluidity of the pigment, the magnetic ceramic pigment of the present invention further includes a hydrophobic modification layer on the surface.

[0007] In the above embodiment, the soft magnetic materials of the present invention are Fe3O4, ferrite (manganese zinc, nickel zinc), aluminum nickel cobalt (cast sintering), iron chromium cobalt (sintering), neodymium iron boron (sintering, bonding), samarium cobalt (sintering, bonding), and aluminum iron carbon (sintering), with a particle size of 0.5 to 3 μm. The protective cosmetic layer is composed of ZrSiO4, ZrO2, TiO2, Al2O3, and SiO2.

[0008] Another object of the present invention is achieved through the following technical solutions:

[0009] The method for preparing the magnetic ceramic colorant as a printing consumable provided by the present invention comprises the following steps:

[0010] (1) Preparation of coated core powder

[0011] The protective cosmetic layer is prepared on the surface of the soft magnetic material particles by a sol-gel method, a homogeneous precipitation method or an in-situ decomposition method to obtain a core-wrapped powder;

[0012] (2) Preparation of primary products

[0013] The coated core powder is mixed with ceramic pigment powder or frit by ball milling, and then calcined at 700-1300° C. to obtain a primary product as a bulk material;

[0014] (3) Preparation of magnetic ceramic pigments

[0015] The bulk material is ball-milled, separated by a magnet, pickled, and screened by a magnet (a magnet is used to separate powder with a magnetic core from powder without a magnetic core, and the powder with a magnetic core is pickled to remove powder whose protective cosmetic layer wrapped around the surface of the magnetic particles is destroyed by the crushing, and then the magnetic ceramic pigment is screened out by a magnet), and dried to obtain a magnetic ceramic pigment; alternatively, the bulk material is further mixed with an ethanol solution of fluorosilane and dried to obtain a magnetic ceramic pigment containing a surface hydrophobic modification layer.

[0016] Furthermore, in the step (1) of the preparation method of the present invention, an in-situ decomposition method is used to add soft magnetic material particles to an aqueous solution of ammonium zirconium carbonate with a concentration of 10-40% to form a stable suspension, wherein the amount of soft magnetic material particles is 10-50wt% of the aqueous solution of ammonium zirconium carbonate; the suspension is heated by a microwave oven to form a zirconium oxide layer on the surface of the soft magnetic material particles (taking advantage of the fact that soft magnetic material particles have a higher wave absorption capacity than water and are more likely to obtain a temperature higher than water during microwave heating; and ammonium zirconium carbonate will decompose into zirconium oxide when heated. In this way, ammonium zirconium carbonate will preferentially decompose on the surface of the soft magnetic material particles to form a zirconium oxide layer); the suspension after microwave treatment is dried and calcined at 500-900°C for 1-3 hours to obtain a core powder coated with a zirconium oxide layer. Alternatively, the suspension after microwave treatment is used The method is to prepare a silicon oxide layer on the surface of the zirconium oxide layer, and calcine it at a temperature above 1000°C in a non-oxidizing atmosphere to obtain a core powder coated with a ZrSiO4 layer.

[0017] Furthermore, the preparation of the magnetic ceramic pigment containing the surface hydrophobic modification layer of the present invention is as follows:

[0018] a. The hydrophobic modifier fluorosilane is added to anhydrous ethanol to prepare a fluorosilane ethanol solution having a concentration of 0.25 to 0.65% as a hydrophobic modifier solution; the dried magnetic ceramic pigment is added to the hydrophobic modifier solution in a mass ratio of hydrophobic modifier solution: magnetic ceramic pigment = 2 to 10:100, and after ultrasonic dispersion, a mixed suspension is obtained;

[0019] b. The mixed suspension is sealed and heated in an oven at 40 to 60°C for 0.5 to 2 hours. After the reaction is complete, the mixed solution is centrifuged and separated. The separated product is washed with anhydrous ethanol and dried to obtain a magnetic ceramic pigment having a surface hydrophobic modification layer.

[0020] The present invention has the following beneficial effects:

[0021] (1) With current technology, the applied magnetic field strength can reach several T, which can achieve a very high magnetic effect. Even for ceramic pigments with high density or large particle size, the force to migrate the corresponding particles can be obtained by changing the magnetic field strength. This makes ceramic pigments with magnetic core have better migration controllability than ceramic pigments with added electrostatic modifiers.

[0022] (2) The present invention uses soft magnetic material as the core material, which has a narrow hysteresis loop. Therefore, it is easy to control the magnetic attraction by controlling the magnetic field strength, and can accurately control the amount of attraction to the ceramic colorant, thereby controlling the chromaticity.

[0023] (3) Since soft magnetic materials contain many elements such as Fe and Mn, they are generally black or gray with a darker color. Therefore, a dense, white wrapping layer is prepared. On the one hand, the density of the wrapping layer is used to protect the soft magnetic material and prevent the diffusion of elements such as Fe and Mn into the outer ceramic pigment to prevent the color of the pigment from changing; on the other hand, the wrapping layer has the function of isolating the black color of the soft magnetic material, and to a certain extent reduces the interference and influence of the color of the soft magnetic core material on the color of the outer ceramic pigment, playing a cosmetic role.

[0024] (4) Soft magnetic materials have strong microwave absorption properties. Under certain microwave heating conditions, soft magnetic material particles are heated first, and the sol tends to gel on these heated particles, or the precipitate tends to deposit on the surface of the soft magnetic material particles. In this way, by controlling the microwave heating power and time, it is easy to control the thickness of the protective cosmetic layer. The process is simple and easy to control.

[0025] (5) Magnetic separation and acid washing can be used to easily and effectively distinguish between particles with a magnetic core and those without a magnetic core, as well as between intact magnetic particles and those with a damaged coating due to crushing. Through magnetic separation-acid washing-magnetic screening, ceramic particles with a structure of a soft magnetic core-an intact protective cosmetic layer-and ceramic pigment can be screened out, and the control process is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings:

[0027] Figure 1 This is a transmission electron microscope photograph of Fe3O4 powder coated with a dense zirconium oxide layer (thickness of 7nm) in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] Example 1:

[0029] The preparation method of the magnetic ceramic colorant used as a printing consumable in this embodiment comprises the following steps:

[0030] (1) Preparation of coated core powder

[0031] Weigh 5 g of Fe3O4 soft magnetic material particles with an average particle size of 0.5 μm, add 0.5 g of 10 wt% PEG solution and 25 g of water, put into a 500 mL beaker, and stir vigorously for 1 hour to form a stable suspension; then add 25 g of 27.48 wt% ammonium zirconium carbonate solution, continue stirring for 1 hour, use a household microwave oven, heat 18 times on medium heat mode, each time for 10 seconds, and then put the microwave-treated suspension into a 60 ° C oven to dry to obtain a powder; the powder is transferred to an alumina crucible, calcined at 900 ° C under N2 atmosphere protection, kept warm for 2 hours, cooled to room temperature, and ground to obtain Fe3O4 powder coated with a dense zirconium oxide layer (see Figure 1 );

[0032] (2) Preparation of primary products

[0033] 2.5 g of the above-mentioned Fe3O4 powder coated with dense zirconia was mixed with 50 g of red frit glaze (previously ball-milled to an average particle size of 2 μm) by dry ball milling for 51 minutes, then placed in a crucible and calcined at 1250°C for 1 hour to obtain a bulk material as the primary product.

[0034] (3) Preparation of magnetic ceramic pigments

[0035] The above-mentioned bulk material is wet-ball-milled for 2 hours to a particle size of 2 μm to obtain a suspension. A strong magnet is inserted into the suspension. After being taken out, the adsorbed magnetic powder is placed in 0.1M HCl for 1 hour to remove the powder whose zirconium oxide layer is damaged by ball milling. The powder is then absorbed by a strong magnet again, and the powder on the surface of the magnet is washed with distilled water to neutrality, and then placed in a blast drying oven to dry, thereby obtaining a magnetic ceramic pigment.

[0036] Alternatively, the obtained magnetic ceramic pigment is further subjected to hydrophobic modification, the steps of which are as follows:

[0037] a. The hydrophobic modifier heptafluorodecyltrimethoxysilane (CF3(CF2)7(CH2)2Si(OCH2CH3)3) was added to anhydrous ethanol to prepare a 0.25% fluorosilane ethanol solution as a hydrophobic modifier solution; the magnetic ceramic pigment was dried in an oven at 80°C for 12 hours, and then the magnetic ceramic pigment was added to the hydrophobic modifier solution at a mass ratio of hydrophobic modifier solution: magnetic ceramic pigment = 4.6:100, and ultrasonically vibrated for 1 hour to ensure that the ceramic pigment was fully dispersed in the hydrophobic modifier solution to obtain a mixed suspension;

[0038] b. The mixed suspension was sealed and heated in a 40°C oven for 1 hour. After the reaction was completed, the mixed solution was centrifuged and separated. The separated product was washed three times with anhydrous ethanol and then dried in a 60°C drying oven for 1 day to obtain a magnetic ceramic pigment containing a surface hydrophobic modification layer.

[0039] Example 2:

[0040] The method for preparing the magnetic ceramic colorant used as a printing consumable in this embodiment differs from that in the first embodiment in that:

[0041] Step (1) The preparation of the coated core powder is as follows:

[0042] In a 1000mL beaker, 80mL of ethanol, 16mL of deionized water and 1g of Fe3O4 soft magnetic material particles with an average particle size of 0.5μm after ultrasonication were added, and stirred with a polytetrafluoroethylene stirring rod. 1mL of 1wt% triblock polymer P123 was added, and after stirring for 0.5h, 3mL of 25wt% ammonia water was added. After stirring for another 0.5h, 1mL of tetraethyl orthosilicate TEOS was added. After the reaction was completed for 1h, the resulting precipitate was washed three times with deionized water and ethanol respectively. The dried powder was calcined at 1100℃ under N2 atmosphere protection, kept warm for 20min, cooled to room temperature, and ground to obtain Fe3O4 powder coated with a dense silica layer.

[0043] Example 3:

[0044] The method for preparing the magnetic ceramic colorant used as a printing consumable in this embodiment differs from that in the first embodiment in that:

[0045] Step (1) The preparation of the coated core powder is as follows:

[0046] 5 g of Fe3O4 soft magnetic material particles with an average particle size of 0.5 μm were weighed, added to 0.5 g of a 10 wt% PEG solution and 25 g of water, placed in a 500 mL beaker, and vigorously stirred for 1 hour to form a stable suspension. 25 g of a 27.48 wt% ammonium zirconium carbonate solution was then added, and stirring continued for 1 hour. The suspension was then heated in a household microwave oven at medium heat for 18 times, each for 10 seconds. The powder was adsorbed to the bottom of the beaker using a magnet, and after removing excess solution, it was washed three times with distilled water. Finally, 20 mL of distilled water was added and ultrasonicated to form suspension A.

[0047] Prepare Solution A: 9 mL of 28% concentrated ammonia, 16.25 mL of ethanol, and 24.75 mL of water in a 150 mL beaker and stir magnetically. Prepare Solution B: 4.5 mL of tetraethyl orthosilicate (TEOS) and 45.5 mL of ethanol in a 100 mL beaker and mix thoroughly. Quickly add Solution B to Solution A to form Solution C.

[0048] The above suspension A was added to solution C, and after rapid stirring, the reaction beaker was sealed with plastic wrap and the reaction was continued at room temperature for 2 hours. After the reaction, the powder was adsorbed on the bottom of the beaker with a magnet, the excess solution was removed, and the powder was washed three times with distilled water. After drying, it was calcined at 1000 ° C under N2 atmosphere protection for 20 minutes. After cooling to room temperature, it was ground to obtain Fe3O4 powder coated with a dense zirconium silicate layer.

Claims

1. A magnetic ceramic colorant as a printing consumable, characterized by: It has a four-layer wrapping structure consisting of an inner core, an intermediate layer, an outer layer, and a surface layer from the inside out. The inner core is soft magnetic material particles, the intermediate layer is a protective cosmetic layer, the outer layer is a ceramic pigment layer, and the surface layer is a hydrophobic modification layer. The chemical composition of the protective cosmetic layer is ZrSiO4, ZrO2, TiO2, Al2O3, and SiO2.

2. The magnetic ceramic colorant as a printing consumable according to claim 1, characterized in that: The inner core radius: the protective cosmetic layer thickness: the outer layer thickness = 1: 0.01-2: 2-6.

3. The magnetic ceramic colorant as a printing consumable according to claim 1, characterized in that: The soft magnetic material is Fe3O4, ferrite, aluminum nickel cobalt, iron chromium cobalt, neodymium iron boron, samarium cobalt, and aluminum iron carbon.

4. The magnetic ceramic colorant as a printing consumable material according to claim 1 or 3, characterized in that: The particle size of the soft magnetic material particles is 0.5 to 3 μm.

5. The method for preparing the magnetic ceramic colorant as a printing consumable material according to any one of claims 1 to 4, characterized in that The following steps are involved: (1) Preparation of coated core powder The protective cosmetic layer is prepared on the surface of the soft magnetic material particles by a sol-gel method, a homogeneous precipitation method or an in-situ decomposition method to obtain a core-wrapped powder; (2) Preparation of primary products The coated core powder is mixed with ceramic pigment powder or frit by ball milling, and then calcined at 700-1300° C. to obtain a primary product as a bulk material; (3) Preparation of magnetic ceramic pigments The block material is ball-milled, separated by a magnet, pickled, and screened by a magnet, dried, and then mixed with an ethanol solution of fluorosilane. The magnetic ceramic pigment containing a surface hydrophobic modification layer is obtained by drying.

6. The method for preparing a magnetic ceramic colorant as a printing consumable material according to claim 5, characterized in that: In the step (1), an in-situ decomposition method is adopted to add soft magnetic material particles into an aqueous solution of ammonium zirconium carbonate with a concentration of 10-40% to form a stable suspension, wherein the amount of soft magnetic material particles used is 10-50wt% of the aqueous solution of ammonium zirconium carbonate; the suspension is heated by a microwave oven to form a zirconium oxide layer on the surface of the soft magnetic material particles; the suspension after microwave treatment is dried and calcined at 500-900°C for 1-3 hours to obtain a core powder coated with the zirconium oxide layer.

7. The method for preparing a magnetic ceramic colorant as a printing consumable material according to claim 6, wherein: The suspension after microwave treatment is subjected to a Stöber method to prepare a silicon oxide layer on the surface of the zirconium oxide layer, and the suspension is calcined at a temperature above 1000° C. in a non-oxidizing atmosphere to obtain a core powder coated with a ZrSiO 4 layer.

8. The method for preparing a magnetic ceramic colorant as a printing consumable material according to claim 5, wherein: The preparation of the magnetic ceramic pigment containing the surface hydrophobic modification layer is as follows: a. A hydrophobic modifier, fluorosilane, is added to anhydrous ethanol to prepare a 0.25 to 0.65% fluorosilane ethanol solution as a hydrophobic modifier solution; the dried magnetic ceramic pigment is added to the hydrophobic modifier solution in a mass ratio of hydrophobic modifier solution: magnetic ceramic pigment = 2 to 10:100, and after ultrasonic dispersion, a mixed suspension is obtained; b. The mixed suspension is sealed and heated in an oven at 40 to 60°C for 0.5 to 2 hours. After the reaction is complete, the mixture is centrifuged and separated. The separated product is washed with anhydrous ethanol and dried to obtain a magnetic ceramic pigment having a surface hydrophobic modification layer.

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