Printing method of high-shielding UV ink and high-shielding UV ink composition

Abstract

The invention provides a printing method of high-shielding UV ink and a high-shielding UV ink composition, and belongs to the technical field of UV ink printing.The printing method comprises the following steps that laser texturing and plasma treatment are conducted on the surface of a product, so that the surface cleanliness meets the requirement; printing 1-10 layers of bottom layer high-adhesive-force UV transparent ink on the qualified product subjected to surface treatment, and performing pre-curing operation on the bottom layer high-adhesive-force UV transparent ink; printing operation of 1-5 layers of surface high-shielding ink is carried out on the product, and final curing is carried out in a special curing mode; and performing appearance detection and grading on the cured product. According to the invention, the limitation of the traditional semitransparent ink is broken through, the problems of large color difference, white exposure, obvious seams, insufficient concealing capability and the like of the appearance are solved through a multi-layer structure and a special process, and the high-standard appearance requirement is met; high shielding rate, strong adhesive force, excellent chemical resistance and uniform curing are realized, and the comprehensive performance of the product is obviously superior to that of the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of UV ink printing, and in particular to a printing method of a high-shielding UV ink and a high-shielding UV ink composition. Background Art

[0002] In order to ensure light penetration and curing, traditional UV ink printing mostly uses translucent ink, which leads to problems such as large color difference, white exposure, obvious seams, and inability to effectively cover substrate defects in the product. It is difficult to meet the high-standard appearance requirements in the fields of electronics and decoration. High-shielding ink has poor light penetration and is prone to the phenomenon of "surface curing but internal wetness", resulting in insufficient adhesion and poor chemical resistance.

[0003] There is an urgent need for a UV ink and printing technology that can achieve high shielding effect, ensure complete curing of the ink, and improve appearance quality and performance stability.

[0004] To this end, a printing method for high-shielding UV ink and a high-shielding UV ink composition are proposed. Summary of the Invention

[0005] The present invention aims to solve the problems raised in the background technology and provides a printing method of high-shielding UV ink and a high-shielding UV ink composition.

[0006] The specific technical solutions are as follows:

[0007] A method for printing high-shielding UV ink comprises the following steps:

[0008] Laser roughening and plasma treatment are performed on the product surface to ensure that the surface cleanliness meets the requirements;

[0009] For products with qualified surface treatment, print 1-10 layers of high-adhesion UV transparent ink and pre-cure them;

[0010] Print 1-5 layers of high-shielding ink on the product and use a special curing method for final curing;

[0011] After curing, the product is inspected and graded for appearance.

[0012] In the above-mentioned high-shielding UV ink printing method, the parameters of the laser texturing process are: laser power 50-150W, scanning speed 100-500mm / s, and spot diameter 0.1-0.5mm;

[0013] The parameters of the plasma treatment are: the treatment gas is argon or air, the gas pressure is 10-100 Pa, and the treatment time is 10-60 s.

[0014] The above-mentioned high-shielding UV ink printing method, wherein the adhesion of the bottom layer high-adhesion UV transparent ink reaches ISO grade 0, the transmittance is ≥90%, and the pre-curing adopts UVLED light source with an energy density of 50-300mJ / cm 2 , curing time 1 to 10 seconds.

[0015] The above-mentioned high-shielding UV ink printing method, wherein the shielding rate of the surface high-shielding ink is ≥99%, and the chemical resistance meets the requirements of no obvious discoloration or falling off after immersion in 5% hydrochloric acid solution, 5% sodium hydroxide solution or 75% ethanol solution for 24 hours.

[0016] The above-mentioned high-shielding UV ink printing method, wherein the special curing method is: using a multi-band UV light source combination curing, including light sources with wavelengths of 365nm, 385nm and 405nm, with a total energy density of 300-1000mJ / cm 2 The curing time is 5 to 30 seconds, and the product maintains a rotation speed of 0 to 100 r / min during the curing process.

[0017] The above-mentioned high-shielding UV ink printing method, wherein the appearance inspection includes color difference inspection, requiring ΔE≤1.0, seam width ≤0.1mm, and no white exposure; the grading standard divides the products into grade A, grade B and grade C according to the test results, among which grade A products meet all appearance index requirements.

[0018] The above-mentioned high-shielding UV ink printing method, wherein the bottom layer high-adhesion UV transparent ink is composed of the following components in parts by weight: 50-70 parts of polyurethane acrylate, 20-30 parts of reactive diluent, 5-10 parts of photoinitiator, and 1-5 parts of adhesion promoter; the surface high-shielding ink is composed of the following components in parts by weight: 40-60 parts of epoxy resin acrylate, 15-25 parts of reactive diluent, 3-8 parts of photoinitiator, 20-35 parts of pigment filler, and 5-10 parts of chemical resistance additive.

[0019] The above-mentioned high-shielding UV ink printing method, wherein the active diluent in the bottom layer high-adhesion UV transparent ink is tripropylene glycol diacrylate and / or dipropylene glycol diacrylate, and the photoinitiator is 1-hydroxycyclohexyl phenyl ketone and / or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0020] In the above-mentioned printing method of high-shielding UV ink, the pigment filler in the surface high-shielding ink is titanium dioxide and / or carbon black, and the chemical resistance additive is a silane coupling agent and / or a fluorocarbon surfactant.

[0021] The present invention also provides a high-shielding UV ink composition for use in the above-mentioned high-shielding UV ink printing method, comprising a bottom layer of high-adhesion UV transparent ink and a surface high-shielding ink; the adhesion of the bottom layer of high-adhesion UV transparent ink reaches ISO grade 0, and the transmittance is ≥90%; the shielding rate of the surface high-shielding ink is ≥99%, and the chemical resistance satisfies the requirement of no obvious discoloration or falling off after immersion in a 5% hydrochloric acid solution, a 5% sodium hydroxide solution, or a 75% ethanol solution for 24 hours.

[0022] The present invention has the following beneficial effects:

[0023] 1. Solve the defects of existing technologies: Break through the limitations of traditional translucent inks. Through a multi-layer structure and special process, it solves problems such as large color difference, white exposure, obvious seams, and insufficient concealing ability, meeting high-standard appearance requirements.

[0024] 2. Comprehensive performance improvement: Achieve high masking rate (masking substrate base color and defects), strong adhesion (ink layer is not easy to fall off), excellent chemical resistance (adapt to chemical environment) and uniform curing (no internal undrying hidden dangers), the overall performance of the product is significantly better than existing technologies.

[0025] 3. Strong process compatibility: Layered printing and modular ink design can adapt to different substrates (such as metal, plastic), broadening the application scenarios of UV inks (such as electronic equipment housings, decorative materials, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a method for printing high-shielding UV ink provided in an embodiment of the present invention;

[0027] Figure 2 A graph showing changes in energy density versus curing time during the pre-curing process of the high-shielding UV ink provided by an embodiment of the present invention;

[0028] Figure 3 A graph showing changes in energy density versus curing time during the final curing process of the high-shielding UV ink provided by an embodiment of the present invention;

[0029] Figure 4 This is a comparison chart of the energy density during the pre-curing and final curing processes of the high-shielding UV ink provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0031] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0032] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inside", "outside" and the like indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] In the description of the present invention, unless otherwise expressly specified or limited, when the term "connection" or the like appears to indicate a connection relationship between components, such term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be internal communication between two components or an interaction between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0034] Example 1

[0035] Reference Figure 1-4 As shown, Figure 1 The process of printing method is shown; Figure 2 It shows how the energy density changes with the increase of curing time in the pre-curing stage. It can be seen from the figure that as the curing time increases, the energy density gradually increases until it reaches a maximum value and remains stable; Figure 3 The energy density in the final curing stage varies with curing time. Similar to the pre-curing stage, the energy density increases with curing time. However, the energy density in the final curing stage has a wider range and a more significant increasing trend. Figure 4 The energy density changes over curing time in the pre-curing and final curing stages were compared. The comparison shows that the energy density in the final curing stage is significantly higher than that in the pre-curing stage, and the energy density change trends in the two stages are different. This embodiment provides a high-shielding UV ink printing method, comprising the following steps:

[0036] S1: Laser roughening and plasma treatment are performed on the product surface to ensure that the surface cleanliness meets the requirements;

[0037] S2: For products with qualified surface treatment, print 1-10 layers of high-adhesion UV transparent ink and pre-cure them;

[0038] S3: Print 1-5 layers of high-shielding ink on the product and perform final curing using a special curing method. The degree of curing is quantified by the following equation: Where:

[0039] D is the degree of curing, which quantifies the degree of cross-linking of the ink from liquid to solid state and directly affects adhesion and chemical resistance;

[0040] n is the number of UV light source bands (n≥2). Multi-band light sources cover different photoinitiator absorption peaks to improve curing efficiency;

[0041] E_i is the energy density of the light source in the i-th band (mJ / cm 2 ), which determines the intensity of the light-initiated reaction. Insufficient energy leads to inadequate curing;

[0042] w_i is the weight coefficient of the i-th band (0<w i ≤1 and ), adjust the contribution of each band according to the ink formula, for example, the weight of the long wavelength (405nm) in high-shielding ink can be increased;

[0043] T is the transmittance of the bottom UV transparent ink, which characterizes the light transmission ability of the bottom transparent ink. The higher T is, the more conducive it is to the deep curing of the surface layer. <T≤1;

[0044] R is the rotation speed of the product during the curing process (r / min). Rotation improves the uniformity of light on the ink surface to avoid local over-curing or under-curing.

[0045] α and β are correction coefficients (α∈[0.8,1.2], β∈[0,0.1]), and D ≥ 0.9 must be ensured to determine complete curing. The compensation parameters adapted to different substrates and ink formulations are determined through process verification.

[0046] S4: After curing, the product is inspected and graded.

[0047] Through the above solution, a multi-layer printing process of "surface treatment → bottom layer printing pre-curing → surface layer printing final curing → detection and grading" is adopted. Through the layered printing design, the bottom transparent ink provides a light penetration channel for the surface layer curing, solving the problem of high-shielding ink curing obstruction; surface treatment enhances the bonding strength between the substrate and the ink, reducing the risk of ink falling off; the multi-layer structure covers the surface defects of the substrate, improving the appearance color difference, white exposure and seam problems.

[0048] Example scenario: For a three-band light source (365nm, 385nm, 405nm) curing process, set the following parameters:

[0049] E_1=300mJ / cm 2 (365nm light source energy density);

[0050] E_2=400mJ / cm 2 (385nm light source energy density);

[0051] E_3=200mJ / cm 2 (405nm light source energy density);

[0052] w_1=0.4 (365nm band weight);

[0053] w_2 = 0.35 (385 nm band weight);

[0054] w_3 = 0.25 (405 nm band weight);

[0055] T = 0.9 (bottom layer transmittance);

[0056] R = 50r / min (product rotation speed);

[0057] α=1.0,β=0.05.

[0058] Substituting the above equation into the calculation results is as follows:

[0059] D=5.52 (after standardization, D=0.92, i.e., 92%).

[0060] Among them, the theoretical value range of the degree of curing D should be 0-1 (0%~100%), but due to the dimensions and calculation methods of the parameters in the equation (such as the large value of the energy density E_i), direct calculation will obtain an intermediate value greater than 1 (such as 5.52 in the example), so it needs to be mapped to a reasonable range through proportional scaling.

[0061] Normalization Method: In practical applications, normalization must be performed based on the maximum theoretical output value of the equation. Assuming that under extreme parameters (such as extremely high energy density across all bands, maximum substrate transmittance, and appropriate rotational speed), the maximum calculated value of the equation is Dmax, then the normalization formula is: Dnormalized = actual calculated value / Dmax. In this example, process verification determined that when Dmax ≈ 6.0 (corresponding to 100% cure), Dnormalized = 5.52 / 6.0 = 0.92.

[0062] Result: When the curing degree D≥0.9, the high-shielding ink is judged to have reached the complete curing standard. The calculated result in the example is 92%, which meets the process requirements.

[0063] Technical effect:

[0064] 1. Accurately quantify the degree of curing: By coupling variables such as multi-band light source energy, bottom layer transmittance, and rotation speed through equations, the degree of curing can be numerically calculated, solving the uncertainty problem of "empirical curing" in traditional processes.

[0065] 2. Optimize process parameters: Based on the equation, the optimal curing parameter combination can be reversely derived. For example, under the premise of ensuring D ≥ 0.9, the curing efficiency and energy consumption can be balanced by adjusting E_i and R.

[0066] 3. Improve product consistency: The quantitative model eliminates the curing differences caused by parameter fluctuations in different production batches, and increases the curing qualification rate of high-shielding inks to over 95%.

[0067] 4. Expand process adaptability: By modifying the coefficients α and β, the equation can be adapted to different substrates such as metal and plastic, as well as ink formulations with different color and obscuration requirements.

[0068] Specifically, in this embodiment, the parameters of the laser texturing treatment are: laser power 50-150W, scanning speed 100-500mm / s, spot diameter 0.1-0.5mm; the parameters of the plasma treatment are: processing gas is argon or air, gas pressure 10-100Pa, and processing time 10-60s.

[0069] Through the combination of laser texturing and plasma treatment surface pretreatment, laser texturing can increase surface roughness, and plasma treatment removes surface impurities and oxides. The combination of the two can improve the surface activity of the substrate, significantly enhance the adhesion between the ink and the substrate, and ensure that the printed layer is not easy to fall off.

[0070] Specifically, in this embodiment, the adhesion of the bottom layer high adhesion UV transparent ink reaches ISO grade 0, the transmittance is ≥90%, and the pre-curing adopts UVLED light source with an energy density of 50-300mJ / cm 2 , curing time 1 to 10 seconds.

[0071] By using UV transparent ink with high adhesion and high transmittance on the bottom layer and pre-curing it, the high transmittance ensures that ultraviolet rays penetrate the bottom layer to reach the surface layer, providing light energy for the curing of the surface layer; pre-curing enables the bottom layer to form a preliminary cross-linked structure, which not only enhances the bonding strength with the substrate, but also provides a flat base for the surface layer printing, reducing leveling defects in subsequent printing.

[0072] Specifically, in this embodiment, the shielding rate of the surface high shielding ink is ≥99%, and the chemical resistance satisfies the requirement of no obvious discoloration or falling off after immersion in 5% hydrochloric acid solution, 5% sodium hydroxide solution or 75% ethanol solution for 24 hours.

[0073] The surface layer uses UV ink with high hiding rate and excellent chemical resistance. The high hiding rate ink covers the base color of the substrate and surface defects, achieving a "concealing" effect and solving the whitening problem of existing technology; the chemical resistance makes the product less likely to change color or fall off in acid, alkali or solvent environments, thereby increasing its service life.

[0074] Specifically, in this embodiment, the special curing method is: using a multi-band UV light source combination curing, including light sources with wavelengths of 365nm, 385nm and 405nm, with a total energy density of 300-1000mJ / cm 2 The curing time is 5 to 30 seconds, and the product maintains a rotation speed of 0 to 100 r / min during the curing process.

[0075] Through the combination of multi-band UV light source curing + product rotation, the multi-band light source covers the absorption wavelengths of different photoinitiators to ensure deep curing of the surface ink; product rotation allows the ink to receive uniform light, avoiding local insufficient curing, and solving the problem of "surface curing but internal undryness" of high-shielding inks in traditional curing methods.

[0076] Specifically, in this embodiment, the appearance inspection includes color difference inspection, which requires ΔE≤1.0, seam width≤0.1mm, and no white exposure; the grading standard divides the products into Grade A, Grade B and Grade C according to the inspection results, among which Grade A products meet all appearance index requirements.

[0077] By designing appearance inspection and grading standards, we eliminate products with appearance defects through systematic inspection, and use graded management to meet the needs of different scenarios, thereby improving product yield and market applicability.

[0078] Specifically, in this embodiment, the bottom layer high adhesion UV transparent ink is composed of the following components in parts by weight: 50-70 parts of polyurethane acrylate, 20-30 parts of reactive diluent, 5-10 parts of photoinitiator, and 1-5 parts of adhesion promoter; the surface high shielding ink is composed of the following components in parts by weight: 40-60 parts of epoxy resin acrylate, 15-25 parts of reactive diluent, 3-8 parts of photoinitiator, 20-35 parts of pigment filler, and 5-10 parts of chemical resistance additive.

[0079] The active diluent in the bottom layer high adhesion UV transparent ink is tripropylene glycol diacrylate and / or dipropylene glycol diacrylate, and the photoinitiator is 1-hydroxycyclohexyl phenyl ketone and / or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the pigment and filler in the surface high shielding ink is titanium dioxide and / or carbon black, and the chemical resistance additive is a silane coupling agent and / or a fluorocarbon surfactant.

[0080] Through the component design of the base and surface inks (such as polyurethane acrylate, epoxy resin acrylate, pigments, fillers, additives, etc.), the adhesion promoter in the base component strengthens the bond with the substrate; the pigments and fillers in the surface layer (such as titanium dioxide) improve the shielding rate, and the chemical resistance additives (such as silane coupling agents) enhance the chemical stability. The synergistic effect of each component realizes functional division of labor.

[0081] Example 2

[0082] This embodiment provides a high-shielding UV ink composition for use in the high-shielding UV ink printing method of Example 1, comprising a bottom layer of high-adhesion UV transparent ink and a surface high-shielding ink; the adhesion of the bottom layer of high-adhesion UV transparent ink reaches ISO grade 0, and the transmittance is ≥90%; the shielding rate of the surface high-shielding ink is ≥99%, and the chemical resistance meets the requirement of no obvious discoloration or shedding after immersion in a 5% hydrochloric acid solution, a 5% sodium hydroxide solution, or a 75% ethanol solution for 24 hours.

[0083] Through the system design of "transparent high-adhesion base layer + high-shielding and chemical-resistant surface layer", a "functional complementarity and performance synergy" overall structure is formed, fundamentally solving the contradiction between appearance and curing of existing technologies from the material level.

[0084] This embodiment also provides a table showing the effect of multi-band light source energy density on the degree of curing (n=3 bands), as follows:

[0085]

[0086] Note: bottom layer transmittance T = 0.9, rotation speed R = 50 r / min, α = 1.0, β = 0.05; actual degree of curing is calculated by measuring the curing exothermic peak area by differential scanning calorimetry (DSC).

[0087] A comparison table between this embodiment and traditional semi-transparent UV ink printing technology is as follows:

[0088] Performance indicators Method of the present invention Traditional technology Improvement Shielding rate (%) 99.5±0.2 85±3 +17.1％ Color difference ΔE 0.8±0.1 2.5±0.3 -68％ Seam width (mm) 0.08±0.02 0.3±0.05 -73.3％ Curing qualification rate (%) 98±1 75±5 +30.7％ Chemical resistance test pass rate 100 80±4 +25％

[0089] The performance comparison table of printing with different layers is as follows:

[0090] Bottom printing layers Surface printing layers Adhesion (ISO grade) Shielding rate (%) Curing time (s) 2 1 Level 1 95 15 6 (best) 3 Level 0 99.5 25 10 5 Level 0 99.8 40

[0091] Technical conclusion: 6 layers of base coat + 3 layers of surface coat are the optimal combination, achieving adhesion level 0 and a masking rate of 99.5% within a curing time of 25 seconds, taking into account both performance and efficiency.

[0092] The deviation analysis between the calculated value and the measured value is as follows:

[0093] Experiment number Calculate the degree of curing D Measured curing degree D' Deviation (ΔD = D - D') Error rate (%) 1 0.85 0.83 +0.02 +2.4 2 0.92 0.91 +0.01 +1.1 3 0.78 0.76 +0.02 +2.6 4 0.98 0.97 +0.01 +1.0

[0094] Statistical results: The average error rate of the 10 sets of experimental data was 1.8%, and the maximum error was ≤3%, which proved that the calculated value of the equation was highly consistent with the actual curing degree and could be used for process parameter optimization.

[0095] Example of parameter optimization guided by equations

[0096] Initial question: A batch of products had a bottom layer transmittance of T = 0.85, resulting in a calculated curing degree value of D = 0.88 (not meeting the standard)

[0097] Equation optimization: By increasing the energy density E3 of the 405nm light source from 200mJ / cm 2 Up to 250mJ / cm 2 , and adjust the weight coefficient w3 from 0.25 to 0.3

[0098] Optimization results: D = 0.91, the measured curing degree is 0.90, which meets the standard; compared with the traditional trial and error method, the parameter adjustment time is shortened from 8 hours to 2 hours.

[0099] Description of experimental methods

[0100] Adhesion test: ISO2409 100-grid test, using 3M600 tape for peeling, level 0 means no peeling;

[0101] Transmittance and shielding rate: UV-Vis spectrophotometer, wavelength range 200-800nm;

[0102] Curing degree: DSC test (heating rate 10 ° C / min, N2 atmosphere), curing degree = 1-(uncured sample exothermic peak area / fully cured sample exothermic peak area);

[0103] Color difference detection: CIELab color difference formula, using Datacolor650 colorimeter, standard light source D65;

[0104] Chemical resistance: GB / T1763-1979 "Determination of resistance of paint films to chemical reagents", observe changes in appearance after immersion.

[0105] The above experimental data are based on the average value of three repeated tests, with a standard deviation of ≤5%, which proves that the method of the present invention is significantly superior to the existing technology in terms of shielding performance, curing effect, appearance quality, etc., and the equation model has good practicality and accuracy.

[0106] In summary, the printing method of high-shielding UV ink provided in this embodiment has the following advantages:

[0107] 1. Solve the defects of existing technologies: Break through the limitations of traditional translucent inks. Through a multi-layer structure and special process, it solves problems such as large color difference, white exposure, obvious seams, and insufficient concealing ability, meeting high-standard appearance requirements.

[0108] 2. Comprehensive performance improvement: Achieve high masking rate (masking substrate base color and defects), strong adhesion (ink layer is not easy to fall off), excellent chemical resistance (adapt to chemical environment) and uniform curing (no internal undrying hidden dangers), the overall performance of the product is significantly better than existing technologies.

[0109] 3. Strong process compatibility: Layered printing and modular ink design can adapt to different substrates (such as metal, plastic), broadening the application scenarios of UV inks (such as electronic equipment housings, decorative materials, etc.).

[0110] How it works

[0111] 1. Surface treatment principle: Laser texturing increases surface roughness through physical etching, while plasma treatment removes pollutants and introduces polar groups through chemical reactions. The two together increase the surface energy of the substrate and enhance the mechanical bite and chemical bonding with the ink.

[0112] 2. Layered printing curing principle:

[0113] 2.1 After the bottom transparent ink is pre-cured, a "light transmission channel" is formed, and ultraviolet rays can penetrate the bottom layer to reach the high-shielding ink on the surface layer;

[0114] 2.2 The photoinitiator in the surface ink absorbs multi-band UV light energy to initiate polymerization. At the same time, the product rotates to ensure uniform light exposure, achieving full thickness curing from the bottom layer to the surface layer;

[0115] 2.3 The functional division of the base layer and the surface layer (the base layer focuses on adhesion, and the surface layer focuses on shielding and chemical resistance) achieves synergy through material design and process coordination.

[0116] 3. Ink curing principle: Photoinitiator generates active free radicals under ultraviolet ray irradiation, which initiates cross-linking polymerization of resin (such as polyurethane acrylate, epoxy resin acrylate) and active diluent, converting liquid ink into solid film.

[0117] How to use

[0118] 1. Substrate pretreatment: Laser texturing and plasma treatment are performed on the product surface to remove impurities such as oil, oxides, etc., and improve surface cleanliness and activity.

[0119] 2. Bottom layer printing: Print 1-10 layers of bottom layer high adhesion UV transparent ink on the pretreated substrate. Pre-curing (UVLED light source irradiation) is performed after each layer is printed to form a transparent and strong bottom layer film.

[0120] 3. Surface printing: Print 1-5 layers of high-shielding UV ink on the bottom layer, and use a multi-band UV light source combination (such as 365nm, 385nm, 405nm) with product rotation for final curing to ensure that the ink is fully cross-linked.

[0121] 4. Quality control: After curing, the product is inspected for appearance (color difference, seams, white exposure, etc.), graded according to standards, and qualified products are screened.

[0122] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A printing method for high-shielding UV ink, characterized in that: The following steps are involved: Laser roughening and plasma treatment are performed on the product surface to ensure that the surface cleanliness meets the requirements; For products with qualified surface treatment, print 1-10 layers of high-adhesion UV transparent ink and pre-cure them; Print 1-5 layers of high-shielding ink on the product and use a special curing method for final curing; After curing, the product is inspected and graded for appearance.

2. The printing method of high-shielding UV ink according to claim 1, characterized in that: The parameters of the laser texturing process are: laser power 50-150W, scanning speed 100-500mm / s, and spot diameter 0.1-0.5mm; The parameters of the plasma treatment are: the treatment gas is argon or air, the gas pressure is 10-100 Pa, and the treatment time is 10-60 s.

3. The printing method of high-shielding UV ink according to claim 1, characterized in that: The adhesion of the bottom layer high adhesion UV transparent ink reaches ISO grade 0, the transmittance is ≥90%, and the pre-curing adopts UVLED light source with an energy density of 50-300mJ / cm 2 , curing time 1 to 10 seconds.

4. The printing method of high-shielding UV ink according to claim 1, characterized in that: The high-shielding ink on the surface has a shielding rate of ≥99%, and has chemical resistance such that there is no obvious discoloration or falling off after being immersed in a 5% hydrochloric acid solution, a 5% sodium hydroxide solution or a 75% ethanol solution for 24 hours.

5. The printing method of high-shielding UV ink according to claim 1, characterized in that: The special curing method is to use a multi-band UV light source combination for curing, including light sources with wavelengths of 365nm, 385nm and 405nm, with a total energy density of 300-1000mJ / cm 2 The curing time is 5 to 30 seconds, and the product maintains a rotation speed of 0 to 100 r / min during the curing process.

6. The printing method of high-shielding UV ink according to claim 1, characterized in that: The appearance inspection includes color difference inspection, which requires ΔE≤1.0, seam width≤0.1mm, and no white exposure; the grading standard divides the products into Grade A, Grade B and Grade C according to the test results, among which Grade A products meet all appearance index requirements.

7. The method for printing high-shielding UV ink according to any one of claims 1 to 6, characterized in that: The bottom layer high-adhesion UV transparent ink is composed of the following components in parts by weight: 50-70 parts of polyurethane acrylate, 20-30 parts of reactive diluent, 5-10 parts of photoinitiator, and 1-5 parts of adhesion promoter; the surface high-shielding ink is composed of the following components in parts by weight: 40-60 parts of epoxy resin acrylate, 15-25 parts of reactive diluent, 3-8 parts of photoinitiator, 20-35 parts of pigment and filler, and 5-10 parts of chemical resistance additive.

8. The method for printing high-shielding UV ink according to claim 7, characterized in that: The active diluent in the bottom layer high-adhesion UV transparent ink is tripropylene glycol diacrylate and / or dipropylene glycol diacrylate, and the photoinitiator is 1-hydroxycyclohexyl phenyl ketone and / or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

9. The method for printing high-shielding UV ink according to claim 7, characterized in that: The pigments and fillers in the surface high-shielding ink are titanium dioxide and / or carbon black, and the chemical resistance additives are silane coupling agents and / or fluorocarbon surfactants.

10. A high-shielding UV ink composition for use in the printing method of the high-shielding UV ink according to any one of claims 1 to 9, characterized in that: It includes a bottom layer of high-adhesion UV transparent ink and a surface high-shielding ink; the adhesion of the bottom layer of high-adhesion UV transparent ink reaches ISO grade 0, and the transmittance is ≥90%; the shielding rate of the surface high-shielding ink is ≥99%, and the chemical resistance meets the requirements of no obvious discoloration or falling off after immersion in 5% hydrochloric acid solution, 5% sodium hydroxide solution or 75% ethanol solution for 24 hours.

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