High-precision cold-stamping printing one-piece flow process

Abstract

The invention discloses a high-precision cold stamping printing one-piece flow process. The process comprises the following steps that S1, surface cleaning is conducted on a printing stock; s2, the surface of the printing stock is coated with UV glue in an ink-jet printing mode; s3, after coating is completed, low-energy UV is adopted for pre-curing, and the energy density is lt; the thickness is 50mJ / cm, and forming a semi-cured adhesive layer; s4, the cold stamping film is attached to the UV glue through an air cushion type pressing roller, then UV full curing is conducted, the cold stamping film is peeled off after curing, and the pattern is reserved on the printing stock; s5, performing color ink overprinting on the hot-stamped pattern to obtain a printed product; and S6, on-line detection and slitting are conducted on the printed matter. According to the high-precision cold-stamping printing one-piece flow process, the whole process is completed in an on-line mode, step-by-step operation is not needed, the production efficiency can be remarkably improved, micron-order pattern control can be achieved through ink-jet coating glue, complex patterns are supported, the glue utilization rate is higher, cold-stamping films are only locally transferred, the waste film rate is reduced, ozone is not generated through LED-UV curing, and the production cost is reduced. And the device is more environment-friendly and lower in energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of printing, and particularly relates to a high-precision cold stamping printing one-piece flow process. Background Art

[0002] Hot stamping technology has a long history in our country and has been rapidly developed and widely applied in recent years. It covers multiple fields such as paper products, textiles, decoration materials, plastic products, etc., and is an important means for workpiece surface decoration.

[0003] As a kind of hot stamping technology, cold stamping printing has the advantages of not needing to make metal hot stamping plates, fast hot stamping speed, no need for heating devices, wide adaptability of hot stamping substrates, etc., providing new opportunities for printing enterprises. Its greatest advantage is less investment, or even no investment at all, high cost performance, which can help customers improve the added value of products and is cost-effective. At present, cold stamping printing technology has become a powerful competitor to hot stamping printing technology and is expanding from the narrow web flexographic printing field to other printing processes such as wide web flexographic printing, letterpress printing, web offset printing, and sheet-fed offset printing.

[0004] Problems existing in the existing cold stamping printing technology: 1. In terms of production efficiency: Traditional cold stamping printing processes usually need to be carried out step by step. For example, steps such as substrate pretreatment, glue coating, cold stamping film transfer, color ink overprinting, inspection and slitting may be completed separately in different equipment or processes. This not only increases the material handling and equipment debugging time in the production process but also easily leads to an extended production cycle and low overall production efficiency. 2. In terms of printing accuracy and quality: Traditional glue coating methods, such as screen printing, are difficult to achieve micron-level pattern control, and the cold stamping effect for complex graphics (such as thin lines, gradient dots) is not good. When printing products with fine patterns, due to the inability to accurately control the coating position and shape of the glue, problems such as blurred and deformed patterns are likely to occur, affecting the aesthetics and quality of the products. If the glue is not properly selected and processed, it is easy for the glue to penetrate the substrate of the cold stamping film, causing difficulties in subsequent peeling, or the adhesion between the cold stamping film and the substrate is insufficient, and the pattern is easy to fall off. During the process of laminating the cold stamping film and the substrate, the pressure distribution of the traditional pressing method is uneven, which is easy to cause mechanical extrusion damage to the hot stamping pattern, affecting the integrity and clarity of the pattern. Especially for some substrates with a soft texture, this extrusion damage is more obvious. 3. In terms of material utilization rate and environmental protection: The glue utilization rate of traditional screen printing methods is only 60 - 70%, and a large amount of glue is wasted during the printing process, increasing production costs. Some traditional curing methods will generate ozone, which is harmful to the environment and the health of operators. At the same time, traditional curing equipment has high energy consumption and does not conform to the current development trend of energy conservation and environmental protection.

[0005] Therefore, it is of great practical significance and market demand to develop a new process that overcomes the limitations of the existing cold stamping printing technology. Summary of the invention

[0006] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a high-precision cold stamping printing one-piece process with reasonable design. The whole process is completed in-line without step-by-step operation, which can significantly improve production efficiency by more than 30%. UV glue is applied by inkjet printing, which can achieve micron-level pattern control, improve glue utilization, and reduce cold stamping film waste. LED-UV curing is used, and no ozone is generated during the curing process, which is more environmentally friendly and has lower energy consumption than traditional UV light sources. It has broad application prospects.

[0007] The objective of the present invention is achieved through the following technical solutions: A high-precision cold stamping one-piece flow process includes the following steps: S1: Clean the surface of the substrate; S2: Apply UV glue on the surface of the substrate by inkjet printing; S3: After coating, low-energy UV is used for pre-curing with an energy density of <50mJ / cm² to form a semi-cured adhesive layer; S4: The cold foil film is laminated with UV glue through an air cushion laminating roller, and then fully cured by UV. After curing, the cold foil film is peeled off, and the pattern remains on the substrate; S5: overprinting color ink on the hot stamped pattern to obtain a printed product; S6: Perform online inspection and slitting on the printed matter.

[0008] The high-precision cold stamping printing one-piece process described in the present invention includes substrate pretreatment, glue coating, pre-curing control, cold stamping film transfer and online lamination, color ink overprinting and functionalization treatment, online detection and slitting. The whole process is completed online without step-by-step operation, and the production efficiency is improved by more than 30%. The use of inkjet glue coating can achieve micron-level pattern control, support complex graphics cold stamping (such as fine lines, gradient dots), glue utilization rate of more than 90% (traditional screen printing is only 60~70%), cold stamping film is only partially transferred, waste film rate is reduced by 50%, LED-UV curing is used without ozone generation, more environmentally friendly, and less energy consumption.

[0009] Furthermore, in the above-mentioned high-precision cold stamping one-piece flow process, in S1, for paper substrates, surface cleaning is performed by a combination of electrostatic dust removal and ion wind cleaning; for plastic substrates, surface cleaning is performed by plasma cleaning or corona treatment, wherein the parameters of plasma cleaning are set as follows: power of 200~300W, processing speed of 5~10m / min, argon or oxygen atmosphere; the parameters of corona treatment are set as follows: surface tension ≥38mN / m, frequency of 10~20kHz, and electrode gap of 1~2mm.

[0010] For paper substrates, a combination of electrostatic dust removal + ion wind cleaning is adopted. Electrostatic dust removal can effectively remove fiber debris on the paper surface, and ion wind cleaning can eliminate dust adsorbed by static electricity, avoiding glue coating defects. For plastic substrates, surface cleaning is carried out by plasma cleaning or corona treatment, which can significantly increase the surface polarity of the plastic and enhance the wettability of the glue. Plasma cleaning is preferred, followed by corona treatment.

[0011] Furthermore, in the above-mentioned one-piece flow process for high-precision cold stamping printing, in S2, UV glue is coated on the substrate surface by inkjet printing. The process parameters of inkjet printing are set as follows: the resolution of the inkjet head ≥ 600 dpi, the ink droplet volume is 6 - 12 pL, the thickness of the glue layer before curing is controlled at 5 - 8 μm, the inkjet printing speed is 20 - 30 m / min, and the nozzle temperature is 35 - 45 °C.

[0012] The thickness of the glue layer is controlled at 5 - 8 μm. If it is too thick, it is easy to cause glue overflow, and if it is too thin, it will affect the adhesion. Coating glue by inkjet printing can accurately control the shape of the glue pattern, without the need for plate making, reducing glue waste.

[0013] Furthermore, in the above-mentioned one-piece flow process for high-precision cold stamping printing, in S2, the viscosity of the UV glue < 200 cps and it is doped with a silane coupling agent.

[0014] A silane coupling agent is doped in the UV glue to enhance the chemical bonding strength with the cold stamping film.

[0015] Furthermore, in the above-mentioned one-piece flow process for high-precision cold stamping printing, in S2, the silane coupling agent is KH-570, and the doping amount is 1.5 - 2.5 wt% of the UV glue.

[0016] After the methoxy group of the KH-570 silane coupling agent is hydrolyzed, it forms a Si-O-Si chemical bond with the imaging layer of the cold stamping film, enhancing the interfacial bonding strength.

[0017] Furthermore, in the above-mentioned one-piece flow process for high-precision cold stamping printing, in S3, low-energy UV is used for pre-curing, the energy density is 20 - 40 mJ / cm², the wavelength is 365 nm, and the curing depth is controlled at 30 - 50% of the total thickness.

[0018] Using low-energy UV pre-curing to form a semi-cured glue layer can avoid the glue from penetrating into the substrate of the cold stamping film, resulting in difficulty in subsequent peeling.

[0019] Furthermore, in the above-mentioned one-piece flow process for high-precision cold stamping printing, in S4, an air-cushioned pressing roller is used for uniform pressing, and the pressure ≤ 5 kg / cm².

[0020] An air-cushioned pressing roller is adopted, and the pressure distribution is more uniform with local fluctuations <±5%. It can dynamically compensate for the thickness error of the printed matter (adapting within ±0.05 mm), reducing mechanical extrusion damage to the hot stamping pattern.

[0021] Furthermore, in the above high-precision cold stamping printing one-piece flow process, in S4, the cold stamping film adopts a five-layer composite structure, successively including a base film, an emulsified water-based wax, an imaging layer, an aluminized layer, and a protective layer.

[0022] Among them, the base film can adopt a PET film, the release layer can adopt an emulsified water-based wax, the imaging layer can adopt an organosilicon acrylic resin, and the protective layer can adopt an ink-friendly layer containing silicon dioxide.

[0023] Furthermore, in the above high-precision cold stamping printing one-piece flow process, in S4, the UV full curing adopts an LED-UV light source with an energy density ≥800 mJ / cm² and a wavelength of 365 nm.

[0024] Preferably, the energy density is 900~1200 mJ / cm². The high energy density can ensure complete cross-linking of the adhesive layer (double bond conversion rate ≥95%), while matching the temperature resistance of the protective layer of the cold stamping film, and the curing time is short. Usually, the curing time ≤0.5 seconds can make the adhesive layer completely cross-linked.

[0025] Furthermore, in the above high-precision cold stamping printing one-piece flow process, in S5, the ink for color ink overprinting adopts UV ink; the printing process of color ink overprinting adopts flexographic press in-line overprinting. The parameter settings of the flexographic press in-line overprinting are: the printing pressure is 0.8~1.2 kg / cm², the closed-loop CCD system error compensation frequency ≥100 Hz, LED-UV curing, and the maximum speed is 50 m / min.

[0026] Furthermore, in the above high-precision cold stamping printing one-piece flow process, in S5, a nano scratch-resistant coating is coated on the surface of the color ink layer to improve wear resistance. The nano scratch-resistant coating adopts a UV-curable nano composite coating (such as BYK-UV 3510), and the coating amount is 1.5~2.5 g / m². The curing conditions are LED-UV (385 nm, 500 mJ / cm²).

[0027] Furthermore, in the above high-precision cold stamping printing one-piece flow process, in S6, a high-resolution linear array camera is used to comprehensively detect the appearance quality, dimensional accuracy, color accuracy, etc. of the printed product, and defective products are removed; according to the customer's requirements and the use of the product, the slitting specifications and dimensions are determined, and laser slitting is adopted with a cutting accuracy of ±0.05 mm, reducing burrs. After slitting, it is automatically stacked + vacuum packaged to avoid secondary pollution.

[0028] Compared with the prior art, the present invention has the following beneficial effects: (1)The one - piece flow process for high - precision cold - stamping printing disclosed by the present invention includes steps such as substrate pretreatment, glue coating, pre - curing control, cold - stamping film transfer and online lamination, color ink overprinting and functionalization treatment, online inspection and slitting. The whole process is completed in - line without step - by - step operation, which avoids the pauses and conversion times between steps in traditional processes, making the production process more compact and smooth, and the production efficiency is increased by more than 30%. (2)In the one - piece flow process for high - precision cold - stamping printing disclosed by the present invention, low - energy UV is used for pre - curing after glue coating, with an energy density < 50mJ / cm², which can quickly form a semi - cured glue layer to prepare for the subsequent cold - stamping film lamination. For UV full - curing, an LED - UV light source is used with an energy density ≥ 800mJ / cm². This rapid curing method reduces the waiting time and improves the production rhythm. Color ink overprinting is carried out by in - line overprinting on a flexographic press, further accelerating the printing speed. (3)In the one - piece flow process for high - precision cold - stamping printing disclosed by the present invention, UV glue is coated by ink - jet printing, which can achieve micron - level pattern control and support cold - stamping of complex graphics. This precise coating method enables the glue utilization rate to reach more than 90%. (4)In the one - piece flow process for high - precision cold - stamping printing disclosed by the present invention, the cold - stamping film is only partially transferred, reducing the waste film rate. In traditional cold - stamping processes, due to the inability to precisely control the transfer area of the cold - stamping film, a large amount of cold - stamping film may be wasted. Through precise glue coating and lamination processes, the cold - stamping film is only transferred in the required pattern area, improving the utilization rate of the cold - stamping film and reducing the material cost. (5)In the one - piece flow process for high - precision cold - stamping printing disclosed by the present invention, LED - UV curing is used, and no ozone is generated during the curing process, which is more environmentally friendly. Throughout the printing process, whether it is the pre - curing or full - curing of the glue, and the curing of color ink overprinting, LED - UV light sources are used, reducing energy consumption and meeting the requirements of energy conservation and emission reduction. (6)In the one - piece flow process for high - precision cold - stamping printing disclosed by the present invention, an air - cushioned lamination roller is used for uniform pressure application, with a pressure ≤ 5kg / cm², a more uniform pressure distribution, and a local fluctuation < ± 5%. It can dynamically compensate for the thickness error of the substrate and reduce the mechanical extrusion damage to the hot - stamping pattern, enabling the cold - stamping film and the substrate to fit better and ensuring the integrity and clarity of the hot - stamping pattern. Detailed implementation mode

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the specific experimental data of Example 1, Example 2, Example 3 and Comparative Example 1. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention. Unless otherwise specified, the reagents, methods and equipment used in the embodiments of the present invention are conventional reagents, methods and equipment in the technical field.

[0030] The following Example 1, Example 2, Example 3 and Comparative Example 1 provide a cold stamping printing process.

[0031] Example 1 The cold stamping printing process of Example 1 includes the following steps: S1 Substrate selection and surface cleaning Select a paper substrate (art paper, with a grammage of 250 g / m² and a thickness of 0.3 mm), and perform surface cleaning by combining electrostatic dust removal and ion wind cleaning. Electrostatic dust removal effectively removes the fiber debris on the paper surface, and ion wind cleaning eliminates the dust adsorbed by static electricity, avoiding subsequent glue coating defects.

[0032] S2 Glue coating Use inkjet printing to coat UV glue (Henkel LOCTITE AA3526) on the surface of the above-mentioned paper substrate, and incorporate 2 wt% of KH-570 silane coupling agent into the UV glue. The process parameters of inkjet printing are set as follows: the resolution of the inkjet head is 600 dpi, the volume of the ink droplet is 8 pL, the thickness of the glue layer before curing is controlled at 6 μm, the inkjet printing speed is 25 m / min, and the temperature of the print head is 40 °C.

[0033] S3 Pre-curing Use low-energy UV for pre-curing, adopt an LED-UV light source, with an energy density of 30 mJ / cm² and a wavelength of 365 nm, and control the curing depth at 40% of the total thickness to form a semi-cured glue layer, avoiding the difficulty of subsequent peeling caused by the penetration of the glue into the substrate of the cold stamping film.

[0034] S4 Cold stamping film transfer and online lamination The cold stamping film adopts a five-layer composite structure, which is successively a base film (Toray Lumirror X10S, 14μm), a release layer (Michelman Michem® Emulsion 91735, 0.4μm), an imaging layer (Sihai SH-024, 1.5μm), an aluminized layer (vacuum aluminized, purity ≥99.9%, 40nm), and a protective layer (Degussa TEGO® Glide 410, 1.0μm). The cold stamping film is adhered to the UV glue through an air-cushioned pressing roller, the pressure is set to 3 kg / cm², the pressure distribution is uniform with a local fluctuation <±5%, and the thickness error of the paper substrate (adaptable within ±0.05mm) is dynamically compensated to reduce mechanical extrusion damage to the hot stamping pattern. Then, full UV curing is carried out using an LED-UV light source with an energy density of 1000 mJ / cm², a wavelength of 365nm, and a curing time of 0.3 seconds to ensure complete cross-linking of the glue layer. After curing, the cold stamping film is peeled off, and the pattern remains on the paper substrate.

[0035] S5 Overprinting of Color Ink and Functionalization Treatment The ink for overprinting color ink uses UV ink (SunCure Accuflex UV ink), and the printing process uses flexographic press in-line overprinting. The parameters are set as follows: printing pressure is 1.0 kg / cm² (ceramic anilox roll), closed-loop CCD system (error compensation frequency 120Hz), LED-UV curing (395nm, 600 mJ / cm², 0.3 seconds), and speed is 40 m / min. A nano scratch-resistant coating (BYK-UV 3510) is coated on the surface of the color ink layer, the coating amount is 2 g / m², and the curing condition is LED-UV (385nm, 500 mJ / cm²).

[0036] S6 On-line Detection and Slitting A high-resolution line array camera is used to comprehensively detect the appearance quality, dimensional accuracy, color accuracy, etc. of the printed matter prepared above, and defective products are removed; according to the customer's requirements and the use of the product, the slitting specifications and dimensions are determined, and laser slitting is used with a cutting accuracy of ±0.05mm to reduce burrs. After slitting, it is automatically stacked + vacuum packaged to avoid secondary pollution.

[0037] Example 2 The cold stamping printing process of Example 2 includes the following steps: S1 Selection of Substrate and Surface Cleaning A plastic substrate (BOPP, thickness 0.2mm) is selected, and surface cleaning is carried out by plasma cleaning. The parameters of plasma cleaning are set as follows: power is 250W, processing speed is 8m / min, and argon atmosphere.

[0038] S2 Glue Coating The UV glue (Henkel LOCTITE AA3526) is coated on the surface of the above-mentioned plastic substrate by inkjet printing, and 1.8 wt% of KH-570 silane coupling agent is incorporated. The process parameters of inkjet printing are set as follows: the resolution of the inkjet head is 700 dpi, the volume of the ink droplet is 10 pL, the thickness of the glue layer before curing is controlled at 7 μm, the inkjet printing speed is 22 m / min, and the temperature of the print head is 42 °C.

[0039] S3 Pre-curing Pre-curing is carried out using low-energy UV, with an energy density of 25 mJ / cm², a wavelength of 365 nm, and the curing depth is controlled at 35% of the total thickness to form a semi-cured glue layer, avoiding the difficulty of subsequent peeling caused by the penetration of the glue into the substrate of the cold stamping film.

[0040] S4 Cold stamping film transfer and online lamination The cold stamping film is the same as that in Example 1. The cold stamping film is adhered to the UV glue through an air-cushioned lamination roller, the pressure is set at 4 kg / cm², the pressure distribution is uniform with a local fluctuation of <±5%, and the thickness error of the plastic substrate is dynamically compensated (adaptive within ±0.05 mm), reducing the mechanical extrusion damage to the hot stamping pattern. Then, UV full-curing is carried out using an LED-UV light source, with an energy density of 1100 mJ / cm², a wavelength of 365 nm, and a curing time of 0.3 seconds to ensure complete cross-linking of the glue layer. After curing, the cold stamping film is peeled off, and the pattern remains on the plastic substrate.

[0041] S5 Color ink overprinting and functionalization The parameters of color ink overprinting are the same as those in Example 1. A nano scratch-resistant coating (BYK-UV 3510) is coated on the surface of the color ink layer, with a coating amount of 2.2 g / m², and the curing conditions are LED-UV (385 nm, 500 mJ / cm²).

[0042] S6 Online inspection and slitting The inspection and slitting methods are the same as those in Example 1.

[0043] Example 3 The cold stamping printing process of Example 3 includes the following steps: S1 Substrate selection and surface cleaning A paper substrate (art paper, with a grammage of 250 g / m² and a thickness of 0.3 mm) is selected, and the cleaning method is the same as that in Example 1.

[0044] S2 Glue coating The UV glue (Henkel LOCTITE AA3526) is coated on the surface of the above-mentioned paper substrate by inkjet printing, and 2.2 wt% of KH-570 silane coupling agent is incorporated. The process parameters of inkjet printing are set as follows: the resolution of the inkjet head is 800 dpi, the volume of the ink droplet is 6 pL, the thickness of the glue layer before curing is controlled at 5 μm, the inkjet printing speed is 28 m / min, and the temperature of the print head is 38 °C.

[0045] S3 Pre-curing Pre-curing is carried out with low-energy UV. An LED-UV light source is used, with an energy density of 35 mJ / cm² and a wavelength of 365 nm. The curing depth is controlled at 45% of the total thickness to form a semi-cured glue layer, avoiding the difficulty of subsequent peeling caused by the glue penetrating the substrate of the cold stamping film.

[0046] S4 Cold stamping film transfer and online lamination The cold stamping film is the same as that in Example 1. The cold stamping film is adhered to the UV glue through an air-cushioned laminating roller, and the pressure is set at 2.5 kg / cm². The pressure distribution is uniform with a local fluctuation of <±5%, and the thickness error of the paper substrate is dynamically compensated (adaptive within ±0.05 mm), reducing the mechanical extrusion damage to the hot stamping pattern. Then, UV full-curing is carried out. An LED-UV light source is used, with an energy density of 950 mJ / cm², a wavelength of 365 nm, and a curing time of 0.4 seconds to ensure complete cross-linking of the glue layer. After curing, the cold stamping film is peeled off, and the pattern remains on the paper substrate.

[0047] S5 Color ink overprinting and functionalization The parameters of color ink overprinting are the same as those in Example 1. A nano scratch-resistant coating (BYK-UV 3510) is coated on the surface of the color ink layer, with a coating amount of 1.8 g / m², and the curing conditions are LED-UV (385 nm, 500 mJ / cm²).

[0048] S6 Online detection and slitting The detection and slitting methods are the same as those in Example 1.

[0049] Comparative Example 1 For the cold stamping printing process of Comparative Example 1, traditional screen printing is used to coat the glue and UV ink. No silane coupling agent is incorporated into the glue. The cold stamping film uses an existing product (KURZ KPW-AL), and traditional mercury lamps are used for UV curing. Other aspects are basically the same as those in the example, including the following steps: S1 Substrate selection and surface cleaning A paper substrate (art paper, with a grammage of 250 g / m² and a thickness of 0.3 mm) is selected, and an ordinary cleaning method is used, only performing simple dust removal.

[0050] S2 Glue coating The above paper substrate is coated with UV glue (Henkel LOCTITE AA3526) by screen printing. The screen mesh count of the screen printing is 300 meshes, and the thickness of the glue layer before curing is controlled at 5 μm.

[0051] S3 Curing Curing is carried out using a traditional mercury lamp with an energy density of 900 mJ / cm², which has high energy consumption and generates ozone.

[0052] S4 Cold stamping film transfer and online lamination The cold stamping film is adhered to the UV glue through a common laminating roller, and the pressure is set at 2.5 kg / cm², with uneven pressure.

[0053] S5 Color ink overprinting The ink for color ink overprinting uses UV ink (SunCure Accuflex UV ink). The printing process uses screen printing technology. The screen mesh count of the screen printing is 300 meshes, and no nano scratch-resistant coating is applied.

[0054] S6 Online inspection and slitting The inspection and slitting methods are the same as those in Example 1.

[0055] Effect verification Experiments were conducted on the printed products obtained in Example 1, Example 2, Example 4, and Comparative Example 1. The experimental results are as follows: The production efficiency of Example 1 was increased by 35% compared with that of Comparative Example 1. The glue utilization rate reached 92%. The waste film rate of the cold stamping film was reduced by 52% compared with that of Comparative Example 1. The adhesion of the hot stamping pattern was detected to reach 4B (cross-cut method). The overprint accuracy of the color ink overprinting reached ±0.03 mm. The wear resistance of the nano scratch-resistant coating was tested by friction test (Taber test, CS-10 wheel, 500 g load). After 1000 times of friction, the coating showed no obvious wear.

[0056] The production efficiency of Example 2 was increased by 33% compared with that of Comparative Example 1. The glue utilization rate reached 91%. The waste film rate of the cold stamping film was reduced by 51% compared with that of Comparative Example 1. The adhesion of the hot stamping pattern reached 4B. The overprint accuracy of the color ink overprinting reached ±0.04 mm. The wear resistance of the nano scratch-resistant coating was tested by friction test (Taber test, CS-10 wheel, 500 g load). After 1000 times of friction, the coating showed no obvious wear.

[0057] The production efficiency of Example 3 was increased by 34% compared with that of Comparative Example 1. The glue utilization rate reached 93%. The waste film rate of the cold stamping film was reduced by 53% compared with that of Comparative Example 1. The adhesion of the hot stamping pattern reached 5B. The overprint accuracy of the color ink overprinting reached ±0.02 mm. The wear resistance of the nano scratch-resistant coating was tested by friction test (Taber test, CS-10 wheel, 500 g load). After 1000 times of friction, the coating showed basically no wear.

[0058] The glue utilization rate of Comparative Example 1 is only 65%, the waste film rate of the cold stamping film is as high as 70%, the adhesion of the hot stamping pattern is only 2B, the overprint accuracy of color ink overprinting reaches ±0.1 mm, the overall quality of the printed matter is poor, and the wear resistance is far inferior to that of Examples 1 to 3.

[0059] It can be seen from the comparison between the above Examples 1 to 3 and Comparative Example 1 that the high-precision cold stamping printing one-piece flow process of the present invention has significant advantages in terms of production efficiency, cost control, environmental protection and energy saving, printing quality, etc.

[0060] There are many specific application ways of the present invention, and the above description is only the preferred embodiment of the present invention. It should be noted that the above examples are only used to illustrate the present invention, and are not used to limit the protection scope of the present invention. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements can be made, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A high-precision cold stamping and printing one-piece flow process, characterized in that The steps include: S1: Clean the surface of the substrate; S2: Apply UV glue on the surface of the substrate by inkjet printing; S3: After coating, low-energy UV is used for pre-curing with an energy density of <50mJ / cm² to form a semi-cured adhesive layer; S4: The cold foil film is laminated with UV glue through an air cushion laminating roller, and then fully cured by UV. After curing, the cold foil film is peeled off, and the pattern remains on the substrate; S5: overprinting color ink on the hot stamped pattern to obtain a printed product; S6: Perform online inspection and slitting on the printed matter.

2. The one-piece flow process for high-precision cold stamping printing according to claim 1, wherein In S1, the surface of the paper substrate is cleaned by combining electrostatic dust removal and ion wind cleaning; For plastic substrates, the surface is cleaned by plasma cleaning or corona treatment; the parameters of plasma cleaning are set as follows: power of 200~300W, processing speed of 5~10m / min, argon or oxygen atmosphere; the parameters of corona treatment are set as follows: surface tension ≥38mN / m, frequency of 10~20kHz, and electrode gap of 1~2mm.

3. The high-precision cold stamping printing one-piece flow process according to claim 1, characterized in that In S2, UV glue is coated on the surface of the substrate by inkjet printing, and the process parameters of inkjet printing are set as follows: inkjet head resolution ≥ 600dpi, ink drop volume 6~12pL, glue layer thickness before curing is controlled at 5~8μm, inkjet printing speed is 20~30m / min, and nozzle temperature is 35~45℃.

4. The high-precision cold stamping printing one-piece flow process according to claim 1, characterized in that, In S2, the viscosity of the UV glue is less than 200 cps, and the UV glue is doped with a silane coupling agent.

5. The high-precision cold stamping printing one-piece flow process according to claim 4, characterized in that, In S2, the silane coupling agent is KH-570, and the amount added is 1.5-2.5 wt % of the UV glue.

6. The high-precision cold stamping printing one-piece flow process according to claim 1, characterized in that, In S3, LED-UV light source is used for pre-curing, with an energy density of 20-40 mJ / cm², a wavelength of 365 nm, and a curing depth controlled at 30-50% of the total thickness.

7. The high-precision cold stamping printing one-piece flow process according to claim 1, characterized in that, In S4, an air cushion type pressing roller is used to apply pressure uniformly, and the pressure is ≤5kg / cm².

8. The high-precision cold stamping printing one-piece flow process according to claim 1, characterized in that, In S4, the cold foil film adopts a five-layer composite structure, which includes a base film, an emulsified water-based wax, an imaging layer, an aluminum-plated layer and a protective layer in sequence.

9. The high-precision cold stamping printing one-piece flow process according to claim 1, wherein In S4, the UV full curing adopts an LED-UV light source with an energy density of ≥800mJ / cm² and a wavelength of 365nm.

10. The high-precision cold stamping printing one-piece flow process according to claim 1, wherein In S5, the ink for color ink overprinting is UV ink; the printing process of color ink overprinting adopts flexographic printing machine in-line overprinting, and the parameters of the flexographic printing machine in-line overprinting are set as follows: printing pressure is 0.8~1.2kg / cm², closed-loop CCD system error compensation frequency is ≥100Hz, LED-UV curing, and the maximum speed is 50m / min.