UV printing process for special surface treatment

Abstract

The invention discloses a UV printing process for special surface treatment, and belongs to the technical field of printing processes, the process comprises the following steps: printing bottom layer UV ink on a printing stock, and irradiating by a UV curing lamp to cure the bottom layer ink; optical interference UV printing ink is printed on the cured bottom layer printing ink, and a UV curing lamp is used for irradiating so that the printing ink can be semi-cured; optical interference UV printing ink is printed on the semi-cured middle layer-1 printing ink, and a UV curing lamp is used for irradiating to cure the printing ink; high-gloss UV ink is printed on the cured middle layer-2 ink, and a UV curing lamp is used for irradiating to cure the ink. According to the process, through the design of middle-layer two-step printing, the interference effect is enhanced, and richer color gradient and layering sense are formed. From the bottom layer to the surface layer, the gloss and color are gradually changed, and a unique and attractive visual effect is presented.

Description

Technical Field

[0001] The invention belongs to the technical field of printing technology, and in particular relates to a UV printing technology for special surface treatment. Background Art

[0002] UV printing is a printing process that uses ultraviolet (UV) radiation to dry and cure ink. This process requires the use of ink containing photosensitizers in conjunction with UV curing lamps. UV printing plays an important role in the printing industry because it can provide a variety of advantages, such as high gloss effects, anti-scratch and anti-scratch properties, special functional touch, and glazing for special graphic surface treatments. UV inks have been widely used in offset printing, screen printing, inkjet, pad printing and many other fields.

[0003] The main purpose of UV printing is to increase the brightness and artistic effect of the product and protect the surface of the product because it has high hardness, corrosion resistance and friction resistance and is not easy to scratch. In addition, UV printing can speed up the completion of the job, especially in short-run printing, because it allows immediate post-press processing.

[0004] For UV printing processes with special surface treatments, this usually involves using specific inks and techniques to create specific effects. For example, UV inks with special effects, such as metallic effects, pearl effects, or matte effects, can be used to create unique visual effects on printed products. In addition, UV printing can also be used to print high-gloss or high-matte surfaces to produce specific tactile and visual effects.

[0005] In UV printing with special surface treatment, the surface of the printed product usually needs special treatment, such as coating, sandblasting or embossing, to increase its surface texture and visual effect. These treatments can be performed before or after printing, depending on the desired effect. Summary of the invention

[0006] The present invention provides a UV printing process for special surface treatment, which has an enhanced interference gloss gradient effect and high wear and scratch resistance. The specific scheme is as follows:

[0007] A UV printing process for special surface treatment includes the following steps:

[0008] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0009] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0010] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0011] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0012] Preferably, the bottom layer ink in S1 is selected from high adhesion and wear-resistant UV ink.

[0013] Preferably, in the printing described in S1, the printing thickness is 0.5-1 μm.

[0014] Preferably, in the curing described in S1, the irradiation power is 500-800 W / cm2 and the irradiation time is 10-15 seconds.

[0015] Preferably, the optical interference UV ink described in S2 has a viscosity of 10-20 mPa·s.

[0016] Preferably, the printing thickness in S2 is 1.5-2 μm.

[0017] Preferably, in the semi-curing step S2, the irradiation power is 400-600 W / cm2 and the irradiation time is 5-8 seconds.

[0018] Preferably, the optical interference UV ink in S3 has a viscosity of 25-40 mPa·s.

[0019] Preferably, the printing thickness in S3 is 2.5-3 μm.

[0020] Preferably, in the curing step S3, the irradiation power is 600-900 W / cm2 and the irradiation time is 15-20 seconds.

[0021] Preferably, the printing thickness in S4 is 2.5-3 μm.

[0022] Preferably, in the curing step S4, the irradiation power is 700-1000 W / cm2 and the irradiation time is 8-12 seconds.

[0023] Beneficial Effects

[0024] Enhanced interference gloss gradient effect: Through the design of two-step printing in the middle layer, not only the interference effect is enhanced, but also a richer color gradient and layering are formed. From the bottom layer to the surface layer, the gloss and color gradually change, presenting a unique and attractive visual effect.

[0025] High wear and scratch resistance: The high adhesion and wear-resistant ink of the bottom layer ensure that the overall printed product has excellent wear and scratch resistance, which is suitable for high-demand usage scenarios. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0029] The inks used in the following examples and comparative examples were purchased through commercial channels:

[0030] High adhesion and wear resistance UV ink: Manufacturer: INX Digital, model: INX-UV-HG-AF (high adhesion and wear resistance UV ink); Optical interference UV ink (low viscosity): Manufacturer: Hubergroup, model: Helioprint UV Optical Interference Low Viscosity (low viscosity optical interference UV ink); Optical interference UV ink (high viscosity): Manufacturer: Hubergroup, model: HelioprintUV OpticalInterference HighViscosity (high viscosity optical interference UV ink); High gloss UV ink: Manufacturer: Hubergroup, model: HelioprintUVHG (high gloss UV ink).

[0031] Embodiment 1 A UV printing process for special surface treatment comprises the following steps:

[0032] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0033] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0034] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0035] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0036] The curing was performed as described in S1, with an irradiation power of 500 W / cm and an irradiation time of 15 seconds.

[0037] S2 The optical interference UV ink viscosity is 10mPa·s.

[0038] S2 is semi-curing, with an irradiation power of 400 W / cm and an irradiation time of 8 seconds.

[0039] S3 The optical interference UV ink viscosity is 25mPa·s.

[0040] The curing was performed as described in S3, with an irradiation power of 600 W / cm and an irradiation time of 20 seconds.

[0041] The curing was performed as described in S4, with an irradiation power of 700 W / cm and an irradiation time of 12 seconds.

[0042] The printing thickness of each step S1-S4 is 2 μm.

[0043] Embodiment 2 A UV printing process for special surface treatment comprises the following steps:

[0044] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0045] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0046] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0047] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0048] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0049] S2 The optical interference UV ink viscosity is 20mPa·s.

[0050] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0051] S3 The optical interference UV ink viscosity is 40mPa·s.

[0052] The curing was performed as described in S3, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0053] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0054] The printing thickness of each step S1-S4 is 2 μm.

[0055] Embodiment 3 A UV printing process for special surface treatment comprises the following steps:

[0056] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0057] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0058] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0059] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0060] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0061] S2 The optical interference UV ink viscosity is 20mPa·s.

[0062] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0063] S3 The optical interference UV ink viscosity is 40mPa·s.

[0064] The curing was performed as described in S3, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0065] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0066] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 1.5 μm. The printing thickness of S3 is 2.5 μm. The printing thickness of S4 is 2.5 μm.

[0067] Embodiment 4 A UV printing process for special surface treatment comprises the following steps:

[0068] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0069] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0070] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0071] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0072] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0073] S2 The optical interference UV ink viscosity is 20mPa·s.

[0074] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0075] S3 The optical interference UV ink viscosity is 40mPa·s.

[0076] The curing was performed as described in S3, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0077] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0078] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 2 μm. The printing thickness of S3 is 3 μm. The printing thickness of S4 is 3 μm.

[0079] Comparative Example 1 A UV printing process comprises the following steps:

[0080] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0081] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0082] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0083] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0084] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0085] S2 The optical interference UV ink viscosity is 20mPa·s.

[0086] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0087] S3 The optical interference UV ink viscosity is 20mPa·s.

[0088] The curing was performed as described in S3, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0089] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0090] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 2 μm. The printing thickness of S3 is 3 μm. The printing thickness of S4 is 3 μm.

[0091] Comparative Example 2 A UV printing process comprises the following steps:

[0092] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0093] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0094] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0095] S4, surface layer printing: high gloss UV ink is printed onto the cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0096] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0097] S2 The optical interference UV ink viscosity is 40mPa·s.

[0098] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0099] S3 The optical interference UV ink viscosity is 40mPa·s.

[0100] The curing was performed as described in S3, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0101] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0102] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 2 μm. The printing thickness of S3 is 3 μm. The printing thickness of S4 is 3 μm.

[0103] Comparative Example 3 A UV printing process comprises the following steps:

[0104] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0105] S2, middle layer printing: Print the optical interference UV ink onto the cured ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0106] S3, surface layer printing: high gloss UV ink is printed onto the cured middle layer ink obtained in S2 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0107] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0108] S2 The optical interference UV ink viscosity is 40mPa·s.

[0109] The curing was performed as described in S2, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0110] The curing was performed as described in S3, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0111] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 3 μm. The printing thickness of S3 is 3 μm.

[0112] Comparative Example 4 A UV printing process comprises the following steps:

[0113] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0114] S2, middle layer printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0115] S3, surface layer printing: high gloss UV ink is printed on the cured middle layer ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and the UV curing lamp is used to irradiate the ink to cure it.

[0116] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0117] S2 The optical interference UV ink viscosity is 20mPa·s.

[0118] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0119] The curing was performed as described in S3, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0120] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 2 μm. The printing thickness of S3 is 3 μm.

[0121] Comparative Example 5 A UV printing process comprises the following steps:

[0122] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0123] S2, middle layer-1 printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0124] S3, middle layer-2 printing: Print the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0125] S4, surface layer printing: high gloss UV ink is printed onto the semi-cured middle layer-2 ink obtained in S3 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0126] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0127] S2 The optical interference UV ink viscosity is 40mPa·s.

[0128] The curing was performed as described in S2, with an irradiation power of 900 W / cm and an irradiation time of 15 seconds.

[0129] S3 The optical interference UV ink viscosity is 20mPa·s.

[0130] S3 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 5 seconds.

[0131] The curing was performed as described in S4, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0132] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 3 μm. The printing thickness of S3 is 2 μm. The printing thickness of S4 is 3 μm.

[0133] Comparative Example 6 A UV printing process comprises the following steps:

[0134] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0135] S2, middle layer printing: Print the optical interference UV ink onto the cured bottom layer ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to semi-cure the ink;

[0136] S3, surface layer printing: high gloss UV ink is printed onto the semi-cured middle layer ink obtained in S2 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0137] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0138] S2 The optical interference UV ink viscosity is 20mPa·s.

[0139] S2 is semi-curing, with an irradiation power of 600 W / cm and an irradiation time of 8 seconds.

[0140] The curing was performed as described in S3, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0141] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 5 μm. The printing thickness of S3 is 3 μm.

[0142] Comparative Example 7 A UV printing process comprises the following steps:

[0143] S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the bottom layer ink;

[0144] S2, middle layer printing: Print the optical interference UV ink onto the cured ink obtained in S1 through the printing screen to ensure that the ink is evenly distributed, and irradiate with a UV curing lamp to cure the ink;

[0145] S3, surface layer printing: high gloss UV ink is printed onto the cured middle layer ink obtained in S2 through a printing screen to ensure that the ink is evenly distributed, and the ink is cured by irradiation with a UV curing lamp.

[0146] The curing was performed as described in S1, with an irradiation power of 800 W / cm and an irradiation time of 10 seconds.

[0147] S2 The optical interference UV ink viscosity is 40mPa·s.

[0148] The curing was performed as described in S2, with an irradiation power of 900 W / cm and an irradiation time of 20 seconds.

[0149] The curing was performed as described in S3, with an irradiation power of 1000 W / cm and an irradiation time of 8 seconds.

[0150] The printing thickness of S1 is 1 μm. The printing thickness of S2 is 5 μm. The printing thickness of S3 is 3 μm.

[0151] Effect detection:

[0152] Enhanced detection of interference gloss gradient effects

[0153] Test standard document number: GB / T 9754-2007 "Determination of gloss of paints and varnishes (20°, 60°, 85°)"

[0154] Detailed detection steps:

[0155] Prepare the sample:

[0156] Select a coating sample with an interference gloss gradient effect and ensure that the surface is free of blemishes and dry.

[0157] Set up the gloss measurement equipment:

[0158] Use a gloss meter and set the measurement angles to 20°, 60°, and 85° according to GB / T 9754-2007. Ensure that the measuring equipment is calibrated and the light source is stable.

[0159] Measuring gloss:

[0160] Select multiple measurement points on the coating surface to ensure that the measurement points are evenly distributed and cover different areas of the interference gloss gradient effect. Use a gloss meter to measure the gloss of each measurement point and record the data in Table 1.

[0161] Analyze the data:

[0162] Compare the gloss data at different measurement points to evaluate the consistency and variation of the interference gloss gradient effect. You can draw a gloss distribution graph to visualize the interference gloss gradient effect.

[0163] Table 1 Sample gloss test data

[0164]

[0165]

[0166]

[0167] We know that the gloss gradient effect can be analyzed from the following perspectives:

[0168] Gloss value: The higher the gloss value, the stronger the surface's ability to reflect light, which usually means better interference effects. Gloss is usually measured on a scale called gloss units (GU), ranging from 0 to 100 or more. A high gloss value usually means a smoother surface, stronger reflections, and thus a more significant interference effect.

[0169] Uniformity of gradient effect: The gradient effect of interference gloss should be uniform and smooth, without sudden changes or jumps. Ideally, the gloss value should gradually increase as the viewing angle increases, forming a smooth transition. If the gradient effect is not uniform, it may affect the overall aesthetics and quality of the interference effect.

[0170] As can be seen from Table 1: Samples 3 and 4 have the highest gloss values ​​and are very close to each other, representing the best gradient effect. Samples 1 and 2 have the second highest gloss values ​​and are also very close to each other, but are significantly lower than 3 and 4. Sample 5 has a lower gloss value than 1 and 2, but is significantly higher than 6, 7, and 11. Samples 6, 7, and 11 have similar gloss values ​​and are at a medium level. Samples 8, 9, and 10 have the lowest gloss values ​​and are close to each other, representing the worst gloss effect. From the perspective of gradient, it can be seen that the gradients of Comparative Examples 4, 5, and 6 are not smooth, and there are sudden changes and jumps, and the effect is not good.

[0171] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0172] The present invention and its implementation methods are described above, and such description is not restrictive, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design methods and embodiments similar to the technical solution without creativity, which should all fall within the protection scope of the present invention.

Claims

1. A UV printing process for special surface treatment, characterized in that: The following steps are involved: S1. Bottom layer printing: Print the bottom layer UV ink onto the substrate, and irradiate with UV curing lamp to cure the bottom layer ink; S2, middle layer-1 printing: printing the optical interference UV ink onto the cured bottom layer ink obtained in S1, and irradiating with a UV curing lamp to semi-cure the ink; S3, middle layer-2 printing: printing the optical interference UV ink onto the semi-cured middle layer-1 ink obtained in S2, and irradiating with a UV curing lamp to cure the ink; S4, surface layer printing: high gloss UV ink is printed on the cured middle layer-2 ink obtained in S3, and the ink is cured by irradiation with a UV curing lamp.

2. The UV printing process for special surface treatment according to claim 1, characterized in that: The bottom layer ink in S1 is selected from high adhesion and wear-resistant UV ink; the printing in S1 has a printing thickness of 0.5-1 μm.

3. The UV printing process for special surface treatment according to claim 1, characterized in that: The curing is carried out as described in S1, with an irradiation power of 500-800 W / cm and an irradiation time of 10-15 seconds.

4. The UV printing process for special surface treatment according to claim 1, characterized in that: S2 The optical interference UV ink has a viscosity of 10-20 mPa·s.

5. The UV printing process for special surface treatment according to claim 1, characterized in that: S2 The printing thickness is 1.5-2 μm.

6. The UV printing process for special surface treatment according to claim 1, characterized in that: S2 is semi-curing, with an irradiation power of 400-600 W / cm2 and an irradiation time of 5-8 seconds.

7. The UV printing process for special surface treatment according to claim 1, characterized in that: S3 The optical interference UV ink has a viscosity of 25-40 mPa·s.

8. The UV printing process for special surface treatment according to claim 1, characterized in that: The printing thickness of S3 is 2.5-3 μm.

9. The UV printing process for special surface treatment according to claim 1, characterized in that: S3 is used for curing, with an irradiation power of 600-900 W / cm2 and an irradiation time of 15-20 seconds.

10. The UV printing process for special surface treatment according to claim 1, characterized in that: The printing thickness of S4 is 2.5-3 μm; the curing of S4 has an irradiation power of 700-1000 W / cm and an irradiation time of 8-12 seconds.

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