Ceramic flower paper preparation method based on laser printing technology and special cover oil thereof

Abstract

The application discloses a ceramic flower paper preparation method based on a laser printing technology and special cover oil, and the method comprises the following steps: preparing ceramic color materials into laser toner, printing patterns on special paper through a laser printer, and then hot-pressing and compounding with a film pre-coated with special cover oil, and then performing water transfer and decalcomania and high-temperature sintering; the cover oil is composed of acrylic acid copolymer, PVB, alcohol solvent and additives in specific proportions, so that the integrity of the printed pattern in the transfer process and complete decomposition and volatilization without defects during sintering are ensured. Through improvement of the physical properties of ceramic color materials, optimization of a process flow and a cover oil formula, the problems of high cost of plate making, insufficient production capacity, poor color performance and low environmental protection in traditional ceramic flower paper production are solved, a digital and personalized ceramic decoration production mode is realized, and the method is suitable for scenes of personalized customized ceramic tableware, artistic decorative ceramic products and the like.

Description

Technical Field

[0001] This invention relates to the field of ceramic decoration and printing materials technology, and in particular to a method for preparing ceramic decals based on laser printing technology and its special cover oil. Background Technology

[0002] Traditional ceramic decal production mainly relies on screen printing. While this technology is mature, it has many limitations: high plate-making costs and long cycles, making it difficult to achieve flexible production of small batches and multiple varieties; insufficient expressiveness for color gradients and high-precision images; and solvent evaporation during the production process, which is environmentally unfriendly.

[0003] Laser printing technology boasts advantages such as high precision, high efficiency, and variable data printing. If applied to the field of ceramic decals, it would greatly simplify the production process and enable personalized customization. However, directly using traditional ceramic pigments for laser printing faces significant challenges:

[0004] 1. Toner problem: The physical properties of traditional ceramic pigments (inorganic metal oxides), such as particle size, density, and charge, are completely incompatible with the requirements of laser toners, making them unusable for printing and transfer.

[0005] 2. Transfer problem: The printed pattern lacks an effective protective layer and transfer medium, and cannot be completely transferred to the ceramic body through water transfer decals like traditional decals.

[0006] 3. Firing issues: The lack of a special coating oil that can perfectly decompose and leave no ash residue during the firing process can easily lead to defects on the ceramic surface.

[0007] Therefore, developing a complete solution that is compatible with laser printing technology and covers everything from materials and printing to transfer and firing is an urgent problem to be solved in this field. Summary of the Invention

[0008] This invention provides a method for preparing ceramic decals based on laser printing technology and its dedicated cover oil. It aims to solve the problems of high plate-making costs, insufficient flexible production capacity, poor color performance, and low environmental friendliness in traditional ceramic decal production by improving the physical properties of ceramic pigments, designing dedicated cover oil, and optimizing the process flow.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A special cover ink for laser printing of ceramic decals, comprising, by weight percentage:

[0011] Film-forming resin: 42% to 60%, wherein the film-forming resin is a mixture of a copolymer of methyl methacrylate and butyl methacrylate and polyvinyl butyral; the molar ratio of methyl methacrylate to butyl methacrylate is 3:7, the glass transition temperature of the copolymer of methyl methacrylate and butyl methacrylate is 40°C to 60°C; the molecular weight of polyvinyl butyral is 50,000 to 80,000, and it is mixed with the copolymer at a mass ratio of 2:1;

[0012] Solvent: 37% to 55%, wherein the solvent is a mixture of ethanol and isopropanol in a mass ratio of 1:1;

[0013] Additives: 3%, comprising leveling agent, defoamer, plasticizer, and initiator; the leveling agent is polyether-modified polydimethylsiloxane, with a content of 0.5%; the defoamer is a non-silicone defoamer, with a content of 0.3%; the plasticizer is dibutyl phthalate, with a content of 1.6%; and the initiator is tert-butyl hydroperoxide, with a content of 0.6%.

[0014] Furthermore, the sum of the weight percentages of the film-forming resin, solvent, and additives is 100%.

[0015] This invention also provides a method for preparing ceramic decals based on laser printing technology. This method uses the aforementioned laser printing-specific cover oil for ceramic decals and specifically includes the following steps:

[0016] S10: Traditional inorganic ceramic pigments are ultra-finely pulverized to a particle size distribution between 5 and 15 micrometers. The pulverized pigments are then surface-modified using silane coupling agent KH-570. The modified pigments are then mixed with resin, charge control agent, and wax to produce ceramic toners in four colors: cyan, magenta, yellow, and black. The resin is a polyester resin; the charge control agent is a quaternary ammonium salt compound, added at 1% of the total pigment mass; and the wax component has a melting point of 70°C.

[0017] S20: The special water transfer paper is loaded into the printer paper tray. The surface of the special water transfer paper includes an ink-absorbing layer and a release layer. The ink-absorbing layer is made of sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 3:7 and has a thickness of 20 micrometers. The release layer is made of paraffin wax and stearic acid in a mass ratio of 4:1 and has a thickness of 10 micrometers. The design pattern is printed on the special water transfer paper under computer control. The printing resolution is set to 1200 dpi or higher, thereby obtaining a paper base with the printed pattern.

[0018] S30: A layer of transparent PET film pre-coated with special cover oil is placed on the printed pattern and then hot-pressed together with a hot press roller at a temperature of 180°C and a pressure of 0.5MPa to form a composite decorative paper film with a printed cover oil film and a paper base. The hot pressing time is 10 seconds. The thickness of the PET film is 50 micrometers and the tensile strength is greater than 150MPa.

[0019] S40: After cutting the composite paper film, soak it in warm water at 38℃ for 5 minutes to separate the printed cover oil film from the paper base, and then attach the printed cover oil film to the surface of the ceramic body; the surface roughness Ra value of the ceramic body is less than 0.5 micrometers.

[0020] S50: Place the ceramic body with the decals applied into the kiln, heat it to 500℃ at a rate of 2℃ per minute and hold it for 10 minutes, then continue to heat it to 900℃ and hold it for 10 minutes before letting it cool naturally.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. Simplified production process: The complex screen printing process is simplified into three steps: "computer design -> laser printing -> hot pressing and lamination", realizing the digitalization, personalization and on-demand production of ceramic decorations.

[0023] 2. High-quality output: By using a special cover oil and leveraging the high precision of laser printing, complex images such as photographs and gradients can be perfectly reproduced, greatly enhancing the artistic expression of ceramic decorations.

[0024] 3. Environmentally friendly and economical: It avoids the plate-making process, reduces the use and waste of solvents, and is especially suitable for small-batch orders, reducing production costs and inventory risks.

[0025] 4. Specialized Material System: The specialized ceramic toner and cover oil formula developed in this invention solves core technical challenges such as laser printing compatibility, pattern transfer integrity, and high-temperature firing without residue, ensuring the quality of the final product.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0028] Figure 1 A schematic diagram of the ceramic decal preparation method based on laser printing technology proposed in this invention. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0030] Example 1: This invention provides a special cover ink for laser printing of ceramic decals, the composition of which, by weight percentage, includes:

[0031] Film-forming resin: 42%. The film-forming resin is a mixture of a copolymer of methyl methacrylate (MMA) and butyl methacrylate (BMA) and polyvinyl butyral (PVB). In the copolymer of MMA and butyl methacrylate, the molar ratio is 3:7, and the glass transition temperature is in the range of 40 to 60°C. The molecular weight of polyvinyl butyral is 50,000 to 80,000, and it is mixed with the copolymer at a mass ratio of 2:1. The copolymer of MMA and BMA balances hardness and flexibility by adjusting the molar ratio (3:7) and the glass transition temperature (40°C-60°C). MMA provides a rigid structure, while BMA introduces flexible segments, giving the copolymer both sufficient hardness to maintain the film shape and flexibility to adapt to bending or friction. Polyvinyl butyral (PVB) is a highly tough and adhesive resin; its molecular weight of 50,000-80,000 ensures the formation of a continuous film. The addition of PVB significantly improves the flexibility and impact resistance of the film, while enhancing adhesion to substrates such as paper and plastics, preventing the film from peeling off due to high temperatures or friction during laser printing. Therefore, the copolymer provides the basic film-forming properties and hardness, while PVB supplements flexibility and adhesion. When mixed at a mass ratio of 2:1, they form a composite film that combines hardness, flexibility, and strong adhesion. This combination is particularly suitable for laser printing cover inks, as it can withstand the high temperatures (laser melting toner) during printing and resist the mechanical stress of frequent cover flipping.

[0032] Solvent: 55%, wherein the solvent is a mixture of ethanol and isopropanol in a mass ratio of 1:1;

[0033] Additives: 3%, comprising leveling agent, defoamer, plasticizer, and initiator; the leveling agent is polyether-modified polydimethylsiloxane, with a content of 0.5%; the defoamer is a non-silicone defoamer, with a content of 0.3%; the plasticizer is dibutyl phthalate, with a content of 1.6%; and the initiator is tert-butyl hydroperoxide, with a content of 0.6%.

[0034] Furthermore, the sum of the weight percentages of the film-forming resin, solvent, and additives is 100%.

[0035] It should be noted that the acrylic copolymer (MMA-BMA) of the film-forming resin undergoes thermal decomposition and cleaves the ester bonds and main chain with PVB at 400-600℃, generating CO2, H2O and low-molecular-weight hydrocarbons; as the temperature rises to 900-930℃, the remaining fragments undergo oxidation reaction with oxygen, completely converting into CO2 and H2O, leaving no solid residue.

[0036] The solvents, ethanol and isopropanol, have low boiling points and evaporate rapidly in the early stages of firing, carrying away moisture and low-boiling-point impurities from the surface oil layer. At the same time, the heat released by the combustion of alcohols can locally raise the temperature, accelerate the pyrolysis reaction of the surrounding polymers, form a catalytic effect, and ensure the overall decomposition efficiency.

[0037] The leveling agent (polyether-modified polydimethylsiloxane), defoamer (non-silicone defoamer), plasticizer (dibutyl phthalate), and initiator (tert-butyl hydrogen peroxide) in the additives all decompose into gases at firing temperatures of 400-900℃, and do not react with each other, allowing them to be discharged with the kiln airflow. Furthermore, the non-silicone defoamer eliminates bubbles generated during the initial firing stage due to solvent evaporation, preventing defects caused by residual gas; the initiator (tert-butyl hydrogen peroxide) thermally decomposes to generate free radicals, catalyzing polymer chain breakage and oxidation reactions, lowering the decomposition temperature, and ensuring complete gasification.

[0038] Therefore, the cover oil using the above components achieves complete gasification and decomposition during the firing process, leaving no solid residue, thus ensuring the integrity of the ceramic decal pattern and the absence of surface defects.

[0039] This invention also provides a method for preparing ceramic decals based on laser printing technology. This method uses the aforementioned laser printing-specific cover oil for ceramic decals and specifically includes the following steps:

[0040] S10: Toner Preparation and Loading

[0041] Traditional ceramic inorganic pigments are ultrafinely pulverized to achieve a particle size distribution between 5 and 15 μm. The ultrafine pulverization is performed using an air jet mill with a working pressure of 0.7 MPa and a classifying wheel speed of 2500 rpm. Because traditional ceramic pigments have poor interfacial bonding with organic matrices, as well as poor dispersibility and compatibility in toner systems, this invention performs surface modification treatment on the pulverized pigments. Silane coupling agent KH-570 is used as a modifier, added at 0.8% of the total pigment mass. The modification treatment temperature is controlled at 80℃ for 3 hours. Among them, silane coupling agent KH-570 is used as a special modifier because it has siloxane alkyl groups (-Si(OCH3)3) and organic functional groups (methacryloyloxy). After hydrolysis, the siloxane alkyl groups (-Si(OCH3)3) undergo a condensation reaction with the hydroxyl groups on the surface of ceramic pigments to form stable siloxane chemical bonds, which can enhance the interfacial bonding force between inorganic pigments and organic matrices. The methacryloyloxy group reacts chemically or physically with subsequently added resins, charge control agents and other organic components, which can improve the dispersibility and compatibility of pigments in toner systems.

[0042] The modified pigments were mixed with resin, charge control agent, and wax in a specific ratio. The resin used was a polyester resin with a softening point range of 80 to 120°C, and its addition amount was 50% to 60% of the total pigment mass. The charge control agent was a quaternary ammonium salt compound, and its addition amount was 1% of the total pigment mass. The wax component was a mixture of paraffin wax and polyethylene wax with a melting point of 70°C, and its addition amount was 8% of the total pigment mass. After mixing, the mixture was processed into ceramic toners in four colors: cyan (C), magenta (M), yellow (Y), and black (K) through crushing, grading, and ball milling. The ball milling time was set to 10 hours, the ball-to-powder ratio was 10:1, and the milling media was zirconia balls.

[0043] The prepared ceramic toner is filled into the drum cartridge, which is then installed into the laser printer.

[0044] S20: Pattern Printing

[0045] The special water transfer paper undergoes a special coating treatment. The ink-absorbing layer is composed of sodium carboxymethyl cellulose and polyvinyl alcohol in a 3:7 mass ratio, with a thickness of 20μm. The release layer is composed of paraffin wax and stearic acid in a 4:1 mass ratio, with a thickness of 10μm. The special water transfer paper is loaded into the printer's paper tray, and the designed color pattern is printed onto the paper under computer control. The printing resolution is set to 1200dpi or higher, and the printing speed is 20 pages per minute, thus obtaining a paper base with the printed pattern.

[0046] S30: Hot-press lamination

[0047] A layer of transparent PET film pre-coated with a special cover oil is placed over the printed pattern and then passed through a hot press. The temperature of the hot press is set to 180℃, the pressure is set to 0.5MPa, and the hot pressing time is 10 seconds, forming a composite decorative paper film of the printed cover oil film and the paper base. The PET film has a thickness of 50μm and a tensile strength greater than 150MPa.

[0048] S40: Water Transfer Decal

[0049] After cutting the laminated paper film, place it in a water bath at 38℃ for 5 minutes. The warm water dissolves the water-soluble adhesive layer on the special water transfer paper, separating the printed cover film from the paper base. Carefully apply the separated printed cover film to the ceramic substrate surface, smoothing it with a rubber squeegee and removing air bubbles and excess water. The surface roughness Ra value of the ceramic substrate should be less than 0.5μm.

[0050] S50: High-temperature firing

[0051] The ceramic body with the decals applied is placed in the kiln and heated to 500°C at a rate of 2°C per minute and held for 10 minutes. Then, the temperature is increased to 900°C and held for 10 minutes before being allowed to cool naturally.

[0052] This application provides application scenarios for the method of preparing ceramic decals, including but not limited to personalized custom ceramic tableware, artistic decorative ceramic products, and industrial identification ceramic parts. The method provided in this application enables flexible production needs for small batches and diverse varieties, meeting market demand for high-quality ceramic decorative materials.

[0053] Example 2, the difference between Example 2 and Example 1 is that: the special cover oil comprises, by weight percentage:

[0054] Film-forming resin: 53%, wherein the film-forming resin is a mixture of a copolymer of methyl methacrylate and butyl methacrylate and polyvinyl butyral; the molar ratio of methyl methacrylate to butyl methacrylate is 3:7, and the glass transition temperature is 40°C to 60°C; the molecular weight of polyvinyl butyral is 50,000 to 80,000, and it is mixed with the copolymer at a mass ratio of 2:1.

[0055] Solvent: 44%, wherein the solvent is a mixture of ethanol and isopropanol in a mass ratio of 1:1;

[0056] Additives: 3%, wherein the additives include leveling agent, defoamer, plasticizer and initiator; the leveling agent is polyether modified polydimethylsiloxane, with a content of 0.5%; the defoamer is a non-silicone defoamer, with a content of 0.3%; the plasticizer is dibutyl phthalate, with a content of 1.6%; the initiator is tert-butyl hydroperoxide, with a content of 0.6%.

[0057] Example 3, the difference between Example 3 and Example 1 is that: the special cover oil comprises, by weight percentage:

[0058] Film-forming resin: 60%, wherein the film-forming resin is a mixture of a copolymer of methyl methacrylate and butyl methacrylate and polyvinyl butyral; the molar ratio of methyl methacrylate to butyl methacrylate is 3:7, and the glass transition temperature is 40°C to 60°C; the molecular weight of polyvinyl butyral is 50,000 to 80,000, and it is mixed with the copolymer at a mass ratio of 2:1.

[0059] Solvent: 37%, wherein the solvent is a mixture of ethanol and isopropanol in a mass ratio of 1:1;

[0060] Additives: 3%, wherein the additives include leveling agent, defoamer, plasticizer and initiator; the leveling agent is polyether modified polydimethylsiloxane, with a content of 0.5%; the defoamer is a non-silicone defoamer, with a content of 0.3%; the plasticizer is dibutyl phthalate, with a content of 1.6%; the initiator is tert-butyl hydroperoxide, with a content of 0.6%.

[0061] Comparative Example 1: Ceramic decals were prepared using a traditional screen printing process and commercially available ordinary ceramic pigments were used. All other conditions were the same as in Example 1.

[0062] Comparative Example 2 uses laser printing technology to prepare ceramic decals, but does not use the special cover oil from Example 1. Instead, it uses cover oil YR-5088Y produced by Starco Company. All other conditions are the same as in Example 1.

[0063] The ceramic decals prepared in each embodiment and comparative example were applied to the ceramic body and placed in a kiln. The temperature was increased to 500°C at a rate of 2°C per minute and held for 10 minutes. Then the temperature was increased to 900°C and held for 10 minutes before natural cooling. The obtained ceramic patterns were tested for pore volume, pattern clarity, color vibrancy, and pattern integrity after firing.

[0064] Among them, the pore volume test was conducted using a porosity analyzer (Bestde 3H-2000PS2) to measure the pore volume;

[0065] The scoring criteria for pattern sharpness (out of 10 points) are based on observation of the sharpness of the pattern edges, the continuity of lines, and the degree of detail reproduction using the naked eye or an optical microscope (e.g., 10-50x magnification). Specifically, clear edges without blurring, jagged edges, or broken lines: 9-10 points; slightly blurry but still discernible: 7-8 points; severely blurry edges or broken lines: ≤6 points.

[0066] Color Vividness Rating (out of 10 points) Rating Criteria: Evaluation of color saturation, brightness, and match with the original design draft through comparison with a color chart (Pantone standard color chart). Specifically: Vivid color, no color difference: 9-10 points; Pale color or slight color difference: 7-8 points; Severely distorted or dull color: ≤6 points.

[0067] Post-firing pattern integrity rating (out of 10 points): The rating is based on visual inspection or low-power microscopy (e.g., 20-100x) to check for pattern integrity after firing, including the absence of cracks, peeling, blistering, or discoloration. Specifically, a complete and defect-free pattern: 9-10 points; minor cracks or localized peeling: 7-8 points; severe cracking or large-area peeling: ≤6 points.

[0068] The experimental results are shown in Table 1:

[0069] <![CDATA[Pore volume (cm 3 / g)]]> Image clarity rating (out of 10) Color vibrancy rating (out of 10) The integrity score of the pattern after firing (out of 10 points) Example 1 0.84 9.7 9.2 9.6 Example 2 0.872 9.6 9.8 9.4 Example 3 0.86 9.3 9.7 9.5 Comparative Example 1 0.65 7.2 6.8 7.0 Comparative Example 2 0.70 7.8 7.5 7.3

[0070] As shown in Table 1, the ceramic decals prepared in this application are superior to the comparative examples in terms of pattern clarity, color vibrancy, and pattern integrity after firing. Comparative Example 1, due to the use of traditional screen printing technology, suffers from high plate-making costs and insufficient color expression; Comparative Example 2, lacking a dedicated cover oil on its ceramic body, experienced partial pattern peeling during firing.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A special cover ink for laser printing of ceramic decals, characterized in that, Its composition, by weight percentage, includes: Film-forming resin: 42% to 60%, wherein the film-forming resin is a mixture of a copolymer of methyl methacrylate and butyl methacrylate and polyvinyl butyral; the molar ratio of methyl methacrylate to butyl methacrylate is 3:7, the glass transition temperature of the copolymer of methyl methacrylate and butyl methacrylate is 40°C to 60°C; the molecular weight of polyvinyl butyral is 50,000 to 80,000, and it is mixed with the copolymer at a mass ratio of 2:1; Solvent: 37% to 55%, wherein the solvent is a mixture of ethanol and isopropanol in a mass ratio of 1:1; Additives: 3%, comprising leveling agent, defoamer, plasticizer, and initiator; the leveling agent is polyether-modified polydimethylsiloxane, with a content of 0.5%; the defoamer is a non-silicone defoamer, with a content of 0.3%; the plasticizer is dibutyl phthalate, with a content of 1.6%; and the initiator is tert-butyl hydroperoxide, with a content of 0.6%. Furthermore, the sum of the weight percentages of the film-forming resin, solvent, and additives is 100%.

2. A method for preparing ceramic decals based on laser printing technology, characterized in that, The method for preparing ceramic decals uses the laser printing cover oil for ceramic decals as described in claim 1, and specifically includes the following steps: S10: Traditional inorganic ceramic pigments are ultra-finely pulverized to a particle size distribution between 5 and 15 micrometers. The pulverized pigments are then surface-modified using silane coupling agent KH-570. The modified pigments are then mixed with resin, charge control agent, and wax to produce ceramic toners in four colors: cyan, magenta, yellow, and black. The resin is a polyester resin; the charge control agent is a quaternary ammonium salt compound, added at 1% of the total pigment mass; and the wax component has a melting point of 70°C. S20: The special water transfer paper is loaded into the printer paper tray. The surface of the special water transfer paper includes an ink-absorbing layer and a release layer. The ink-absorbing layer is made of sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 3:7 and has a thickness of 20 micrometers. The release layer is made of paraffin wax and stearic acid in a mass ratio of 4:1 and has a thickness of 10 micrometers. The design pattern is printed on the special water transfer paper under computer control. The printing resolution is set to 1200 dpi or higher, thereby obtaining a paper base with the printed pattern. S30: A layer of transparent PET film pre-coated with special cover oil is placed on the printed pattern and then hot-pressed together with a hot press roller at a temperature of 180°C and a pressure of 0.5MPa to form a composite decorative paper film with a printed cover oil film and a paper base. The hot pressing time is 10 seconds. The thickness of the PET film is 50 micrometers and the tensile strength is greater than 150MPa. S40: After cutting the composite paper film, soak it in warm water at 38℃ for 5 minutes to separate the printed cover oil film from the paper base, and then attach the printed cover oil film to the surface of the ceramic body; the surface roughness Ra value of the ceramic body is less than 0.5 micrometers. S50: Place the ceramic body with the decals applied into the kiln, heat it to 500℃ at a rate of 2℃ per minute and hold it for 10 minutes, then continue to heat it to 900℃ and hold it for 10 minutes before letting it cool naturally.

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