High-insulation high-shielding intaglio printing ink and preparation method thereof

Abstract

The invention relates to the technical field of printing ink, in particular to high-insulation and high-shielding intaglio printing ink and a preparation method thereof. The high-insulation and high-shielding intaglio printing ink is prepared from the following raw materials in percentage by weight: 15 to 25 percent of polar polyester resin, 6 to 10 percent of carbon black, 2 to 6 percent of organic bentonite, 2 to 5 percent of nano-scale filler, 4 to 6 percent of micron-scale filler, 1 to 2 percent of dispersing agent, 0.5 to 1.2 percent of silane coupling agent, 0.1 to 0.5 percent of flatting agent, 18 to 25 percent of mixed solvent and the balance of saturated polyester resin. The nanoscale filler is a boron nitride nanosheet or a mixture of the boron nitride nanosheet and nano silicon dioxide; the gravure printing ink has the advantage of simultaneously improving the covering power and insulativity of the gravure printing ink.

Description

Technical Field

[0001] This application relates to the technical field of printing inks, and in particular to a high-insulation, high-shield gravure printing ink and its preparation method. Background Technology

[0002] In the current gravure printing ink market, although there is a wide variety of products, inks specifically designed for high insulation and high opacity are relatively scarce. With the rapid development of the electronics industry, the demand for high-insulation, high-opacity gravure printing inks is increasing daily. Currently, 3C consumer electronics have become necessities in work and life, commonly including smartphones, laptops, and smartwatches. Compared to their functional requirements, appearance design is equally important. Not only are aesthetically pleasing, lightweight, and easy to carry required, but increasingly stringent size requirements are also being imposed.

[0003] Due to size requirements, the space occupied by batteries in electronic devices is becoming increasingly smaller, necessitating thinner battery pack insulation materials. Besides selecting thinner, more dimensionally stable, and lower-cost film materials, battery size can also be reduced by decreasing the thickness of the insulating black ink coating on the film surface. This necessitates a gravure black ink with superior hiding power and insulation properties, while also exhibiting excellent adhesion and flexibility on ultra-thin PET films. Regarding hiding power, commonly available high-hitting gravure insulating inks typically achieve full opacity (OD value of 4) with two coats and a total film thickness of 8 micrometers or more. However, achieving full opacity with only one coat and a total film thickness of 5-6 micrometers places even higher demands on hiding power. As for insulation, most commercially available products have a surface resistivity of around 10... 10 -10 11 For ink coatings with a surface resistivity between Ω and 10 Ω, which do not meet the needs of end customers, the surface resistivity is greater than or equal to 10 Ω. 12 Ω. Therefore, there is an urgent need to develop a gravure printing ink with high opacity and high insulation. Summary of the Invention

[0004] In order to simultaneously improve the hiding power and insulation of gravure printing ink, this application provides a high-insulation, high-shielding gravure printing ink and its preparation method.

[0005] In a first aspect, this application provides a high-insulation, high-shield gravure printing ink, employing the following technical solution: A high-insulation, high-shield gravure printing ink comprises the following raw materials in weight percentages: 15-25% polar polyester resin, 6-10% carbon black, 2-6% organic bentonite, 2-5% nano-sized filler, 4-6% micron-sized filler, 1-2% dispersant, 0.5-1.2% silane coupling agent, 0.1-0.5% leveling agent, 18-25% mixed solvent, and the balance being saturated polyester resin; The nanoscale filler is boron nitride nanosheets or a mixture of boron nitride nanosheets and nano-silica.

[0006] By adopting the above technical solution, the gravure printing ink prepared in this application incorporates polar polyester resin, whose polar groups can enhance the wettability and adhesion to the PET substrate through hydrogen bonding. Carbon black, acting as the primary shielding agent, provides high hiding power. The added organic bentonite, forming nanoscale silicate sheets, aligns under shear force during ink drying, creating a nanoscale layered framework that provides an adhesion substrate for micron-sized fillers. The added nanoscale fillers fill the pores on the ink surface. The organic bentonite, nanoscale fillers, and micron-sized fillers together create a micro / nanostructured surface in the ink. The hiding power of the fillers and carbon black, combined with the micro / nanostructure, enhances light dispersion. The effect of radiation significantly improves the hiding power, achieving full coverage at a thickness of 4μm, i.e., an OD value of over 4. Furthermore, the organic bentonite and nano-sized filler boron nitride possess high insulation and thermal conductivity, resulting in high insulation of the ink. The presence of organic bentonite also enhances the dispersibility of solid fillers. Organic bentonite can form a three-dimensional network adhesive structure within the system, exhibiting thixotropic properties, preventing solid fillers from settling, improving ink stability, and resulting in excellent micro-nano structures formed on the ink surface after drying. In summary, the gravure printing ink prepared in this application possesses both high insulation and high hiding power, and exhibits strong adhesion to PET, demonstrating significant application potential.

[0007] Preferably, the average particle size of the nanoscale filler is 30-100 nm.

[0008] By adopting the above technical solution, nanoscale fillers of this particle size can help form the micro-nano structure surface of ink, which is beneficial for dispersion in ink system.

[0009] Preferably, when the nanoscale filler is a mixture of boron nitride nanosheets and nano-silica, the mass percentage of the added nano-silica is ≤25% of the nanoscale filler.

[0010] By adopting the above technical solution, excessive addition of nano-silica is not conducive to improving its insulation properties. However, adding a certain amount of it to replace boron nitride nanosheets is beneficial to saving costs. Taking all factors into consideration, when the addition amount is ≤25%, it can balance the insulation of the ink and cost control.

[0011] Preferably, the micron-sized filler is a mixture of titanium dioxide and mica powder, wherein the mass ratio of titanium dioxide to mica powder is 1:(3-5).

[0012] By adopting the above technical solution, a small amount of titanium dioxide can work synergistically with carbon black to improve the hiding power of ink, but the amount should not be too much, as too much will easily lead to a decrease in the blackness of the ink color.

[0013] Preferably, the average particle size of the micron-sized filler is 1-5 μm.

[0014] By adopting the above technical solution, titanium dioxide of this particle size can form the micro-nano surface of ink, and has good dispersibility in the system and is not easy to settle.

[0015] Preferably, the dispersant is a fluorinated dispersant.

[0016] By adopting the above technical solution, the fluorocarbon chain of the fluorinated dispersant has extremely low surface energy, which can effectively prevent filler agglomeration and can synergize with the silane coupling agent. The former is adsorbed on the surface of the filler, and the latter reacts with the resin to form a stable interface structure of "filler-dispersant-coupling agent-resin".

[0017] Preferably, the molecular structure of the silane coupling agent contains one or more of hydroxyl, carboxyl, and epoxy groups.

[0018] By adopting the above technical solution, when the molecular structure of the silane coupling agent contains hydroxyl, carboxyl and epoxy groups, it can achieve better wettability with PET substrate.

[0019] Secondly, this application provides a method for preparing a high-insulation, high-shield gravure printing ink, employing the following technical solution: A method for preparing a high-insulation, high-shield gravure printing ink, comprising the following steps: S1. After mixing the saturated polyester resin and polar polyester resin evenly, add the organic bentonite, heat to 50-70℃, and premix for 30-60 minutes to obtain a pre-activated mixture. S2. Add nano-sized fillers and dispersants to the mixed solvent, disperse by ultrasonication, and then continue to perform high-speed shearing at a speed of 2500-4000 rpm for 0.5-2 h to obtain a nano-sized filler dispersion. S3. Add nano-sized filler dispersion and remaining raw materials to the pre-activated mixture, and shear at a shear rate of 1500-2500 rpm for 30-60 minutes to obtain high-insulation and high-opacity gravure printing ink.

[0020] By adopting the above technical solution, the interlayer spacing of organic bentonite can be expanded through pre-activation, creating conditions for subsequent nanofiller intercalation. The nanofiller can be fully dispersed through ultrasound and high-speed shearing. Then, the pre-activated mixture, nanofiller and remaining raw materials are mixed and sheared to make the raw materials uniformly mixed and the system stable.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. The gravure printing ink prepared in this application incorporates polar polyester resin, whose polar groups can enhance the wettability and adhesion to the PET substrate through hydrogen bonding. Carbon black serves as the primary shielding agent, providing high hiding power. Organic bentonite, forming nanoscale silicate sheets, aligns under shear force during ink drying, creating a nanoscale layered framework that provides an adhesion substrate for micron-sized fillers. The added nanoscale fillers fill the pores on the ink surface. The organic bentonite, nanoscale fillers, and micron-sized fillers together create a micro / nanostructured surface in the ink. The hiding power of the fillers and carbon black, combined with the enhanced light scattering effect of the micro / nanostructure, further contributes to this process. This significantly improves the hiding power, achieving full coverage at a thickness of 4 μm, meaning the OD value can reach above 4. Furthermore, the organic bentonite and nano-sized filler boron nitride possess high insulation and thermal conductivity, resulting in high insulation properties for the ink. The presence of organic bentonite also enhances the dispersibility of solid fillers. Organic bentonite can form a three-dimensional network adhesive structure within the system, exhibiting thixotropic properties, preventing solid fillers from settling and improving ink stability. This results in excellent micro-nano structures formed on the ink surface after drying. In summary, the gravure printing ink prepared in this application possesses both high insulation and high hiding power, and exhibits strong adhesion to PET, demonstrating significant application potential.

[0022] 2. The gravure printing inks prepared in this application all achieve an adhesion strength of 5B to PET substrates and a surface resistivity of 10. 12+ In terms of Ω and opacity, their OD values ​​can all reach above 4.0, with the highest reaching 4.5; indicating that the gravure printing ink prepared in this application has both high insulation and high opacity, and its wettability on PET substrate is excellent, which has great application potential in high-precision printing. Detailed Implementation

[0023] The following provides a more detailed description of this application in conjunction with specific details.

[0024] raw material All raw materials used in the embodiments of this application are commercially available products. The saturated polyester resin was purchased from Sanmu Group, model SM-515; the polar polyester resin was manufactured by Wanhua Chemical, model [missing information]. 5600; the dispersant is a fluorinated modified wetting agent, model BYK-348; the leveling agent is model HX3060; the carbon black is purchased from Tianjin Donghai Carbon, model TD-110, with a particle size of 50-70nm and a specific surface area of ​​200m². 2 / g; Organic bentonite was purchased from Zhejiang Fenghong New Material Co., Ltd., model FH-GC-2. Example

[0025] Example 1 A high-insulation, high-shield gravure printing ink, the raw materials and their amounts are shown in Table 1, and its preparation method is as follows: S1. After mixing the saturated polyester resin and polar polyester resin evenly, add the organic bentonite, heat to 65℃, and premix for 40 minutes to allow the organic bentonite to fully swell and achieve pre-activation of the organic bentonite, thus obtaining a pre-activated mixture. The mixed solvent is a mixture of ethyl acetate and propylene glycol methyl ether; the nanoscale filler is a mixture of boron nitride nanosheets and nano-silica with an average particle size of 50 nm and a mass ratio of boron nitride nanosheets to nano-silica of 3:1; the micron-scale filler is a mixture of titanium dioxide and mica powder with a mass ratio of titanium dioxide to mica powder of 1:4 and an average particle size of 1 μm; the silane coupling agent is KH560. S2. Add nano-sized fillers and dispersants to the mixed solvent, ultrasonically disperse for 20 min, and then continue high-speed shearing at a shearing speed of 3000 rpm for 1 h to obtain a nano-sized filler dispersion. S3. Add nano-sized filler dispersion and remaining raw materials to the pre-activated mixture, and shear at a shear rate of 2000 rpm for 40 min to obtain high-insulation and high-opacity gravure printing ink.

[0026] Table 1. Raw materials and their quantities (kg) in Example 1 Example 2 A high-insulation, high-shield gravure printing ink differs from Example 1 in that the mass ratio of boron nitride nanosheets to nano-silica is 4:1, while the remaining steps are the same as in Example 1.

[0027] Example 3 A high-insulation, high-opacity gravure printing ink differs from Example 1 in that it does not contain nano-silica in its nano-level filler, while the remaining steps are the same as in Example 1.

[0028] Example 4 A high-insulation, high-shield gravure printing ink differs from Example 1 in that the amount of organic bentonite added is 6 kg, while the remaining steps are the same as in Example 1.

[0029] Example 5 A high-insulation, high-shield gravure printing ink differs from Example 1 in that the amount of organic bentonite added is 2 kg, while the remaining steps are the same as in Example 1.

[0030] Comparative Example Comparative Example 1 A high-insulation, high-opacity gravure printing ink differs from Example 1 in that it does not contain organic bentonite in its raw materials, while the remaining steps are the same as in Example 1.

[0031] Comparative Example 2 A high-insulation, high-opacity gravure printing ink differs from Example 1 in that its nano-level filler is nano-silica, while the remaining steps are the same as in Example 1.

[0032] Comparative Example 3 A high-insulation, high-opacity gravure printing ink differs from Example 1 in that it does not contain titanium dioxide in its micron-level filler, while the remaining steps are the same as in Example 1.

[0033] Performance testing Detection methods / test methods Gravure printing inks were prepared according to the preparation methods of Examples 1-5 and Comparative Examples 1-3, and then tested according to the following testing methods. The test results are shown in Table 2.

[0034] The gravure printing inks prepared in Examples 1-5 and Comparative Examples 1-3 were coated and then tested. The coating substrate was a PET substrate, the coating film thickness was 4 μm, and all were coated in one step. The film thickness was tested by a film thickness tester, the hiding power was tested by an LH-230 high-precision transmittance tester, the resistance was tested by a surface resistivity meter, and the adhesion was tested by the cross-cut adhesion test.

[0035] Table 2 shows the test results of Examples 1-5 and Comparative Examples 1-3. As can be seen from Examples 1-5, Comparative Examples 1-3, and the test data in Table 2, the gravure printing inks prepared in this application all achieve an adhesion of 5B to the PET substrate and a surface resistivity of 10.12+ In terms of Ω and opacity, their OD values ​​can all reach above 4.0, with the highest reaching 4.5; indicating that the gravure printing ink prepared in this application has both high insulation and high opacity, and its wettability on PET substrate is excellent, which has great application potential in high-precision printing.

[0036] The test data from Example 1 and Comparative Example 1 show that the gravure printing ink prepared in this application contains polar polyester resin, whose polar groups can enhance the wettability and adhesion to the PET substrate through hydrogen bonding. Carbon black is used as the main shielding agent, and the added organic bentonite forms nanoscale silicate sheets. During ink drying, these sheets are oriented under shear force, forming a nanoscale layered framework that provides an adhesion substrate for the micron-sized fillers. The added nanoscale fillers fill the pores on the ink surface. The organic bentonite, nanoscale fillers, and micron-sized fillers together create a surface with a micro / nano structure in the ink. The hiding power of fillers and carbon black, combined with the enhanced light scattering effect of the micro-nano structure, significantly improves the hiding power. A thickness of 4 μm achieves full hiding power, meaning the OD value can reach above 4. Furthermore, organic bentonite and nano-sized filler boron nitride possess high insulation and thermal conductivity, resulting in high insulation of the ink. The presence of organic bentonite also improves the dispersibility of solid fillers. Organic bentonite can form a three-dimensional network adhesive structure within the system, exhibiting thixotropic properties, preventing solid fillers from settling, improving ink stability, and resulting in a well-formed micro-nano structure on the ink surface after drying. Based on Examples 4-5, the appropriate addition amount of organic bentonite is between 2-6%.

[0037] The test data from Examples 1-3 and Comparative Example 2 show that excessive addition of nano-silica is not conducive to improving its insulation properties. However, adding a certain amount of it to replace boron nitride nanosheets is beneficial for saving costs. Considering all factors, when the addition amount is ≤25%, it can balance the insulation properties of the ink and cost control.

[0038] The test data from Example 1 and Comparative Example 3 show that a small amount of titanium dioxide can work synergistically with carbon black to improve the hiding power of ink, but the amount should not be too much, as too much can easily lead to a decrease in the blackness of the ink color.

[0039] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A high-insulation, high-shield gravure printing ink, characterized in that: It comprises the following raw materials by weight percentage: 15-25% polar polyester resin, 6-10% carbon black, 2-6% organic bentonite, 2-5% nano-sized filler, 4-6% micron-sized filler, 1-2% dispersant, 0.5-1.2% silane coupling agent, 0.1-0.5% leveling agent, 18-25% mixed solvent, and the balance being saturated polyester resin; The nanoscale filler is boron nitride nanosheets or a mixture of boron nitride nanosheets and nano-silica.

2. The high-insulation, high-shield gravure printing ink according to claim 1, characterized in that: The average particle size of the nanoscale filler is 30-100 nm.

3. The high-insulation, high-shield gravure printing ink according to claim 1, characterized in that: When the nanoscale filler is a mixture of boron nitride nanosheets and nano-silica, the mass percentage of the added nano-silica is ≤25% of the nanoscale filler.

4. The high-insulation, high-shield gravure printing ink according to claim 1, characterized in that: The micron-sized filler is a mixture of titanium dioxide and mica powder, and the mass ratio of titanium dioxide to mica powder is 1:(3-5).

5. The high-insulation, high-shield gravure printing ink according to claim 4, characterized in that: The average particle size of the micron-sized filler is 1-5 μm.

6. The high-insulation, high-shield gravure printing ink according to claim 1, characterized in that: The dispersant is a fluorinated dispersant.

7. The high-insulation, high-shield gravure printing ink according to claim 1, characterized in that: The molecular structure of the silane coupling agent contains one or more of the following: hydroxyl, carboxyl, and epoxy groups.

8. A method for preparing a high-insulation, high-shield gravure printing ink according to any one of claims 1-7, characterized in that: It includes the following steps: S1. After mixing the saturated polyester resin and polar polyester resin evenly, add the organic bentonite, heat to 50-70℃, and premix for 30-60 minutes to obtain a pre-activated mixture. S2. Add nano-sized fillers and dispersants to the mixed solvent, disperse by ultrasonication, and then continue to perform high-speed shearing at a speed of 2500-4000 rpm for 0.5-2 h to obtain a nano-sized filler dispersion. S3. Add nano-sized filler dispersion and remaining raw materials to the pre-activated mixture, and shear at a shear rate of 1500-2500 rpm for 30-60 minutes to obtain high-insulation and high-opacity gravure printing ink.

Images