Printing method for composite packaging material structure with built-in hidden anti-fake laser image-text

Abstract

The invention discloses a printing method for a composite packaging material structure with built-in hidden anti-fake laser images and texts. The method comprises the following steps: converting designed images and texts into digital images and texts; manufacturing a plate by using a laser photoetching machine to obtain an image-text nickel plate; making the digital image-text into a gravure plate; a high-precision micron-sized optical positioning mark is preset on a PET (Polyethylene Terephthalate) base film; printing transparent UV gloss oil by using a gravure plate, and dynamically adjusting the UV gloss oil coating position of a gravure press according to the real-time tracking of the position of the PET base film; performing film pressing on the PET base film on which gloss oil is completed and an image-text nickel plate, performing curing through an ultraviolet light curing lamp and then performing stripping, performing photocuring by adopting a photocuring process of pre-curing and then scanning an image through a scanning probe to compare and correct offset, and performing secondary full-curing to fix the pattern; coating and coloring the PET base film; carrying out vacuum aluminum plating on the coated PET base film; and compounding the PET base film subjected to vacuum aluminum plating with 200g roll white card, and feeding into a gravure press to finish printing. Precise overprinting of the local UV laser cold transfer pattern printed matter is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite packaging materials with anti-counterfeiting laser graphics, and specifically relates to a printing method for the structure of a composite packaging material with built-in latent anti-counterfeiting laser graphics. Background Art

[0002] The UV laser cold transfer stamping technology, commonly known as the C² process (Cast and Cure), is an innovative post-printing process that combines UV curing technology with holographic laser effect transfer. Traditional laser effects are mostly achieved through laser transfer paper, that is, after embossing laser patterns on PET or OPP films, aluminizing is carried out, and then it is compounded and embossed with paper and peeled off for transfer. This process has high costs, poor environmental protection, and the laser effect is easily covered by dark printing. With the improvement of environmental protection requirements and cost control pressure, the UV laser cold transfer stamping process has emerged. Its core breakthrough lies in that there is no need for aluminizing, and the holographic pattern of the transparent laser film is directly transferred to the surface of the printed matter through UV varnish, which not only retains the visual effect but also reduces material consumption. This process is achieved by printing varnish on a single-sheet glazing machine and then laminating with a prefabricated transfer film. The prefabricated film can be used more than 20 times, realizing the transparent laser cold transfer effect of the product, with both anti-counterfeiting and decorative functions, and combined with special plates (such as text or pattern laser films), enhancing the visual appeal of the product, and has been widely used in the fields of cigarette packages, wine labels, cosmetics, and high-end gift packaging.

[0003] The disadvantages of the existing UV laser cold transfer stamping technology are also relatively obvious, which limits its further application in the industry. The reasons are as follows: on the one hand, since the glazing varnish is very easy to overflow, the overprinting effect of local laser cold stamping transfer is generally ≥0.5mm, which cannot meet the registration requirements of high-grade fine products; on the other hand, the surface solvent resistance of the products processed by the UV laser cold transfer process is relatively poor, and the laser pattern can be damaged by applying water and sweat. If the surface is laminated again for protection or overcoated with varnish, the laser effect will directly disappear. These reasons have hindered the application and promotion of the UV laser cold transfer process in the packaging and printing industry. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a printing method for the structure of a composite packaging material with built-in latent anti-counterfeiting laser graphics, realizing accurate overprinting of local UV laser cold transfer pattern printed matter, with the laser pattern not easily damaged and better anti-counterfeiting effect.

[0005] The technical solution adopted by the present invention is: a printing method for the structure of a composite packaging material with built-in latent anti-counterfeiting laser graphics, the method comprising the following steps:

[0006] Step 1: Convert the designed graphics into digital graphics;

[0007] Step 2: Use a laser lithography machine to make a plate, and obtain a nickel plate with graphics and text.

[0008] Step 3: Make the digital graphics and text in Step 1 into an intaglio plate.

[0009] Step 4: Select a PET base film with a thickness of 16 - 20 um, and preset high-precision micron-level optical positioning marks on the PET base film.

[0010] Step 5: Use the intaglio plate in Step 3 to print transparent UV varnish. Combine with the multi-spectral sensor on the printing machine to track the position of the PET base film in real time. Adjust the coating position of the UV varnish on the intaglio printing machine by scanning the position change, with an error ≤ ±0.1 mm.

[0011] After printing the transparent UV varnish, laminate the PET base film with the nickel plate with graphics and text in Step 2. Cure it with an ultraviolet light curing lamp and then peel it off. Adopt a two-stage ultraviolet light curing process: After the first pre-curing, scan the image with a scanning probe to compare and correct the offset. The power of the UV lamp for pre-curing < 50%. Fix the pattern in the second full curing, and the power of the UV lamp for the second full curing is 100%. Ensure the pixel-level alignment of the laser layer and the printed layer. Obtain a PET base film layer with a local laser pattern through Step 6.

[0012] Step 7: Coat the base film in Step 6 with an adhesive layer and then send it into a coater for full-surface coating and coloring, with the background color mainly being dark.

[0013] Step 8: Send the coated PET base film into a vacuum aluminizing machine for vacuum aluminizing operation.

[0014] Step 9: Compound the PET dark film in Step 8 with a 200 g roll of white cardboard, and then send it into an intaglio printing machine for multi-color printing to obtain a packaging material with a hidden local laser cold transfer composite printing structure. The multi-spectral sensor on the printing machine tracks the optical positioning marks on the base film in real time to ensure the precise registration of the laser graphics and text with the later printed graphics and text.

[0015] Further, in Step 1 above, the designed graphics and text are processed and converted into digital graphics and text using vector software.

[0016] Further, in Step 2 above, at the bleeding position on the surface of the nickel plate with graphics and text, overprint registration lines and positioning tracking marks are made.

[0017] Further, in Step 3 above, at the bleeding position on the surface of the intaglio plate, the same overprint registration lines and positioning tracking marks as in Step 2 are engraved.

[0018] The beneficial effects of the present invention: Compared with the prior art, the effects of the present invention are as follows:

[0019] 1) The present invention breaks through the technical bottleneck that traditional full-scale laser cannot be locally positioned, enhances the high-end visual effect of packaging printed matter, and is applicable to high-value-added products such as tobacco and alcohol packaging.

[0020] 2) An integrated scanning image probe is used to automatically match the contour features of the laser pattern and the design draft, and the pressure of the impression roller and the tension of the base film are adjusted in real-time with feedback, realizing full-process closed-loop control.

[0021] 3) The final product has the metallic texture of aluminized materials and also has the anti-counterfeiting function of hidden laser graphics and texts.

[0022] 4) The structure of the composite packaging material obtained by the present invention is, from the inside to the outside in sequence: paper layer → water-based environmental protection glue layer → vacuum aluminized layer → nano-coating layer → local laser pattern + positioning cursor layer → PET base film → printed graphics and texts, forming a "laser layer embedded type" anti-counterfeiting barrier. The laser pattern layer is embedded between the coating color layer and the base film through a cold transfer process. To damage the laser pattern, it is necessary to simultaneously damage the printing layer and the base film layer, and the physical anti-counterfeiting strength is increased by more than 3 times.

[0023] 5) The hidden laser graphics and texts have non-replicable optical anti-counterfeiting characteristics. Utilizing the refractive index difference (Δn≥0.3) between the aluminized layer and the coating layer, the laser pattern presents a dynamic rainbow light effect at a specific angle, while the scanner can only obtain a blurred image because it cannot capture the holographic diffraction effect.

[0024] 6) The coating layer uses a dark material, which can widen the brightness contrast between the background color and the laser pattern. The hidden laser pattern appears under strong light for anti-counterfeiting.

[0025] 7) Breaking through the defect that traditional surface lasers are easily worn and replicated, the anti-counterfeiting verification can be quickly identified through strong light (such as a mobile phone flashlight), and it is applicable to high-security demand scenarios such as certificates and luxury goods. Description of the Drawings

[0026] Figure 1 It is a process flow chart of a printing method for the structure of a composite packaging material with built-in hidden anti-counterfeiting laser graphics and texts;

[0027] Figure 2 It is a schematic diagram of the structure of a composite packaging material with built-in hidden anti-counterfeiting laser graphics and texts;

[0028] In the figure, 1 is the PET base film layer; 2-1 is the local laser pattern layer; 2-2 is the positioning cursor layer;

[0029] 3 is the dark coating layer; 4 is the aluminized layer; 5 is the water-based glue layer; 6 is the paper layer;

[0030] 7-1 is the printed graphics and texts layer; 7-2 is the printed positioning cursor layer.

[0031] Figure 3Printing effect diagram of the printing structure (under strong light irradiation);

[0032] Figure 4 It is a laser pattern on a PET base film. Specific implementation manner

[0033] The present invention will be further introduced below in conjunction with specific embodiments.

[0034] Example 1: As Figures 1-4 shown, a printing method for a composite packaging material structure with built-in latent anti-counterfeiting laser graphics and texts, the method comprising the following steps:

[0035] Step 1: Convert the designed graphics and texts into digital graphics and texts;

[0036] In step 1, the designed graphics and texts are processed and converted into digital graphics and texts using ai or other vector software;

[0037] Step 2: Use a laser lithography machine to make a plate, and obtain a graphic nickel plate; at the bleeding position on the surface of the graphic nickel plate, make overprint registration lines and positioning tracking marks;

[0038] Step 3: Make the digital graphics and texts in step 1 into a gravure plate; at the bleeding position on the surface of the gravure plate, engrave the same overprint registration lines and positioning tracking marks as in step 2;

[0039] Step 4: Select a PET base film with a thickness of 16 - 20 um, and pre-set high-precision micron-level optical positioning marks on the PET base film;

[0040] Step 5: Print transparent UV varnish with the gravure plate in step 3, combine with a multi-spectral sensor on the printing machine to track the position of the PET base film in real time, and adjust the coating position of the UV varnish on the gravure printing machine by scanning the position change, with an error ≤ ±0.1 mm;

[0041] After printing the transparent UV varnish, laminate the PET base film with the graphic nickel plate in step 2, cure it by an ultraviolet light curing lamp and then peel it off. Adopt a two-stage ultraviolet light curing process: after the first pre-curing, scan the image with a scanning probe to compare and correct the offset, the power of the UV lamp for pre-curing < 50%, fix the pattern by secondary full curing, and the power of the UV lamp for secondary full curing is 100% to ensure pixel-level alignment of the laser layer and the printing layer, and obtain the PET base film layer 2 with local laser patterns through step 6;

[0042] Step 7: Coating the base film in step 6 with an adhesive layer and then sending it into a coater for full-surface coating and coloring, with the background color mainly being dark;

[0043] Step 8: Send the coated PET base film into a vacuum aluminizing machine for vacuum aluminizing operation;

[0044] Step 9: Composite the PET dark film obtained in Step 8 with 200g reel white cardboard, and then send it to an intaglio printing press for multi-color printing to obtain a packaging material with a hidden partial laser cold transfer composite printing structure. The multispectral sensor on the printing press tracks the optical positioning marks on the base film in real time to ensure the precise registration of the laser graphics position and the graphics printed later.

[0045] As Figure 2 shown, the composite packaging material structure includes a PET base film layer 1, a partial laser pattern layer 2-1, a positioning cursor layer 2-2, a dark coating layer 3, an aluminized layer 4, an aqueous glue layer 5, a paper layer 6, a printed graphics layer 7-1, and a printed positioning cursor layer 7-2. The paper layer 6, the aqueous environmental protection glue layer 5 (with a thickness of 5-10μm), the vacuum aluminized layer 4 (with a reflectivity ≥85%), and the nano-coating layer 3 (mainly made of dark materials) are arranged from the inside to the outside. A partial laser pattern layer 2-1 is arranged inside and positioning cursor layers 2-2 are arranged on both sides between the nano-coating layer 3 and the PET base film layer 1 (with a thickness of 12-25μm). A printed positioning cursor layer 7-2 facing the positioning cursor layer 2-2 is arranged on both sides outside the PET base film layer 1, and a printed graphics layer 7-1 facing the partial laser pattern layer 2-1 is arranged inside. Compared with the conventional structure, there is no PET base film layer in the conventional structure, and the UV laser graphics are on the printing layer and directly exposed outside, lacking protection and being easily damaged and imitated. In this application, with the PET base film layer, the partial laser pattern is set inside the PET base film layer. On the one hand, it plays a role in protecting the laser pattern and is not easily damaged. On the other hand, it is not necessary to be built into the PET base film layer, making it not easy to imitate and having a better anti-counterfeiting effect. The positioning cursor layer 2-2 and the printed positioning cursor layer 7-2 are set to facilitate registration positioning during the printing process and have a higher positioning accuracy.

[0046] As mentioned above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A method for printing a composite packaging material structure with hidden anti-counterfeiting laser images, characterized in that: The method comprises the following steps: Step 1: Convert the design graphics into digital graphics; Step 2: Use laser lithography to make a nickel plate with images and texts; Step 3: Make the digital image in step 1 into a gravure plate; Step 4: Select a PET base film with a thickness of 16-20um, and pre-set high-precision micron-level optical positioning marks on the PET base film; Step 5: Print transparent UV varnish with the gravure plate in step 3, and use the multi-spectral sensor on the printing press to track the position of the PET base film in real time, and dynamically adjust the UV varnish coating position of the gravure printing press, with an error of ≤±0.1mm; Step 6: After printing the transparent UV varnish, the PET base film is pressed with the nickel plate with the graphic in step 2, and peeled off after curing with a UV curing lamp. A two-stage UV curing process is adopted: after the first pre-curing, the image is scanned by a scanning probe to correct the offset, the power of the UV lamp for pre-curing is less than 50%, and the pattern is fixed by the second full curing. The power of the UV lamp for the second full curing is 100%, ensuring the pixel-level alignment of the laser layer and the printing layer. The PET base film layer with a local laser pattern is obtained through step 6; Step 7: After coating the base film in step 6 with a glue layer, send it into a coating machine for full-plate coating and coloring, with the base color mainly being dark; Step 8, sending the coated PET base film into a vacuum aluminum coating machine for vacuum aluminum coating; Step nine, compound the dark PET film in step eight with the 200g roll white card, and then send it into the gravure printing machine for multi-color printing to obtain a hidden partial laser cold transfer composite printing structure packaging material. The multi-spectral sensor on the printing machine tracks the optical positioning mark on the base film in real time to ensure that the position of the laser image and the image printed later are accurately registered.

2. The method for printing a composite packaging material structure with hidden anti-counterfeiting laser images and texts according to claim 1, characterized in that: In step one, the graphic and text designed are converted into digital graphics and text using vector software.

3. The method for printing a composite packaging material structure with hidden anti-counterfeiting laser images and texts according to claim 1, characterized in that: In step 2, make the overprint guide line and positioning tracking mark at the bleed position of the graphic nickel plate.

4. The method for printing a composite packaging material structure with hidden anti-counterfeiting laser images and texts according to claim 1, characterized in that: In step three, the same overprinting guide line and positioning tracking mark as in step two are engraved at the bleed position of the gravure plate.

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