High-flash silver sand transfer backing paper printing method based on photoetching and film pressure technology

Abstract

The invention discloses a high-flash silver sand transfer backing paper printing method based on photoetching and film pressing technologies, which comprises the following steps of: scanning the appearance effect of high-speed bright silver frosted PET (Polyethylene Terephthalate) composite paper through a high-power scanner to obtain a fine picture, performing makeup and platemaking on the picture according to a printing width to obtain a laser engraving nickel plate, and performing printing on the laser engraving nickel plate to obtain the high-flash silver sand transfer backing paper. A PET base film is coated with a UV transparent coating and then subjected to film pressing with a nickel plate, a PET base film plate face with the concave-convex shape of high-flash silver frosted particles is obtained under ultraviolet light curing, finally, transfer body paper with the laser diffuse reflection effect of the high-flash silver frosted transfer structure is obtained through a film pressing composite transfer technology, and then the transfer body paper with the laser diffuse reflection effect of the high-flash silver frosted transfer structure is obtained by combining priming varnish and back coating protection. And online printing production is realized. By means of the method, it can be guaranteed that the trademark has the appearance effect of the high-flash silver frosted composite material, and all the defects of the composite material can be effectively overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of high-shiny silver sand transfer base paper printing, and relates to a high-shiny silver sand transfer base paper printing method based on photolithography and film pressing technology. Background Art

[0002] The high-end cigarette labels and cosmetics produced by the printing process of high-shiny silver frosted special ink coated on PET base film composite materials have a very gorgeous and elegant appearance and a very significant decorative effect. After being applied and promoted on the "Guiyan (Hard Small Country Liquor Fragrance)" cigarette label products, they have received great market attention. However, since its shiny effect depends on the reflection of the crystal cross section of the crystalline particles of the high-shiny silver frosted ink, the coating thickness of the frosted ink layer on the PET base film is very high. The corresponding PET base film is thicker than ordinary composite paper, with a thickness of about 20-40um, and the conventional composite film thickness is generally 12-16um. Since the average particle size of the main crystalline particles of the high-shiny silver frosted ink is greater than 10um, the distribution of the surface of each crystal during coating production is random. At present, there is no technical solution to control the cross section of each grain to be arranged in a consistent direction. Therefore, the composite material printing process using frosted PET film coating has the following problems: 1) The slight difference in the arrangement of silver sand particles leads to a particularly large color difference between batches of base paper raw materials. The average color difference △E ≥ 1.8 is tested. When combined with the difference in each printing production control, the color difference is very likely to exceed the industry control standard of △E>2.5; 2) Trademarks made of PET-based film composite materials are prone to warping and deformation during processing due to the difference in water absorption performance on both sides, and jamming occurs during molding on the machine, affecting operating efficiency; 3) Moreover, the PET base film is non-degradable and will cause environmental problems such as white pollution. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a high-shiny silver sand transfer base paper printing method based on photolithography and film pressing technology, which can not only ensure that the trademark has the appearance effect of a high-shiny silver frosted composite material, but also effectively avoid all the shortcomings of the composite material.

[0005] The technical solution adopted by the present invention is: a high-shiny silver sand transfer base paper printing method based on photolithography and film pressing technology, the method comprising the following steps: Step 1: Scan the image. Determine the standard sample of high-shiny silver frosted PET composite paper according to the customer's sample requirements, select a clean, tidy and clear sample, and scan the image with a high-magnification scanning device with a resolution greater than 1200DPI and not higher than 6000DPI; Step 2: Image processing: layout according to the printing machine width, which is 740*610mm or 730*515mm, and convert the image scanned in step 1 into a high-resolution digital file. This step realizes the analog-to-digital conversion of the high-shining silver sand graphic image; Step 3: Laser engraving nickel plate production, nickel plate substrate selection: use high-purity electrolytic nickel plate (purity ≥ 99.99%), the surface must be flat and free of impurities; laser system selection: use fiber laser, wavelength 355nm, engraving accuracy 5-30μm; working parameters: power: 10-50W; scanning speed: 100-2000mm / s, high-speed engraving requires synchronous adjustment of pulse frequency; focus control: use dynamic focusing lens to ensure that the laser spot diameter is ≤20μm; engraving mode: directly ablate grooves or microstructures on the nickel surface through vector scanning to form the uneven shape of the photolithography pattern; this step realizes the multi-faceted three-dimensional processing of high-shining silver sand digital graphic images; Step 4: Imprint the base film, select a PET base film with a thickness of 14-17um, and process the PET base film. The processing process includes dust removal and static electricity removal. The dust removal operation is to directly adhere large particles on the surface of the base film through a sticky roller, and use a high-speed airflow (0.3-0.6MPa) to blow away loose particles. The air knife angle is 30°~45° (to avoid damaging the surface of the base film). At the same time, the ionized airflow neutralizes static electricity. Cleaning speed: synchronized with the production line speed (usually 100-120 m / min, adjusted according to the thickness of the base film). The roll feeding requires the end face to be neat, the left and right swing error is ≤1.0-1.5mm, and the winding tension is stable. The base film is coated with a peeling layer, a glue layer and a UV transparent coating in turn through multiple sets of coating rollers, and then immediately compounded with a nickel plate before the UV transparent coating dries. The pressure is 1.5-2.5kg, and it is baked and dried by a UV curing machine, and then peeled off to obtain a PET base film with an uneven surface; this step realizes the microscopic multi-faceted three-dimensional structure of a highly shiny silver sand digital graphic image; Step 5: Send the PET base film in step 4 to a high vacuum winding aluminum plating machine for aluminum plating to increase the apparent metal effect of the product; Step 6: Compound and transfer the vacuum aluminum-plated PET base film to the paper. The film surface glue is coated with an anilox roller. The PET base film and the composite paper are separated from the peeling layer. The glue layer, the aluminum-plated layer and the UV transparent coating containing a microscopic multi-faceted three-dimensional structure are transferred to the surface of the paper to achieve transfer and deplasticization treatment respectively. Step 7: Processing: Apply special varnish to the printed surface after transfer. The special varnish is a colorless transparent liquid. The standard viscosity is 18-25S when measured with a Caien No. 3 cup. At the same time, the back of the paper is back-coated. The solid content of the back-coating liquid is 25-30%. The standard viscosity is 17-20S when measured with a Caien No. 3 cup. Step 8: In-line printing production, the paper processed in step 7 is printed in-line.

[0006] Furthermore, the thickness of the electrolytic nickel plate is 0.1-0.5 mm, and the purity is ≥99.99%.

[0007] Furthermore, in the above step three, the laser engraving of the nickel plate is performed by at least three times of photolithography superposition to form a three-dimensional texture effect.

[0008] Furthermore, the glue in the above step six is ​​water-based transfer glue, with a solid content of >40% and a transfer amount of 4.5-6.0 g / ㎡; the composite transfer pressure is 2.0-3.0 kg, the printing roll tension is 5.0-7.5 kg, and the drying temperature is 95-110°C.

[0009] Furthermore, the inks required for printing the main pattern produced by the online printing in the above step eight use matte inks and high-transparency inks with strong contrast, and the relative contrast coefficient is greater than 60%, thereby increasing the contrast effect of the product.

[0010] Beneficial effects of the present invention: Compared with the prior art, the present invention has the following effects: 1) Since the pictures are converted into high-resolution digital files using CAD or vector software, the color difference of the entire batch of paper is △E<1.0. The visual effect is consistent when observed from any angle, eliminating the color difference problem caused by the difference in particles of high-shiny silver frosted ink used in the original process, and the diffuse reflection layer is more uniform and smooth; 2) The final finished product trademark material eliminates the PET film, reducing resource waste and the formation of white pollution; 3) Removing the PET base film also avoids the inherent deformation and warping problems of composite paper raw materials, improves the controllability of production quality, and increases the input-output ratio of each batch from the original 85%-90% to 95%-97.5%, reducing production costs and improving production efficiency; 4) Determine the laser engraving parameters through experiments. In this case, according to the appearance of the "Guiyan (hard small country wine aroma)" composite material, select a cell depth of 5-6um; a screen angle of 45° and a screen line number of 200L, and superimpose the photolithography three times to maximize the simulation of the diffuse reflection effect of the original particles coated with high-gloss silver frosted ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a process flow chart of a high-shiny silver sand transfer paper printing method based on photolithography and film pressing technology; Figure 2 This is the effect picture of the high-shiny silver sand transfer paper 1 obtained by photolithography and film pressing technology (rougher effect); Figure 3This is the effect picture of the high-shiny silver sand transfer paper 2 obtained by photolithography and film pressing technology (thinner effect); Figure 4 It is a high-shiny silver sand composite paper with PET base film using the original process. DETAILED DESCRIPTION

[0012] The present invention is further described below in conjunction with specific embodiments.

[0013] Example 1: Figure 1-4 As shown, a high-shiny silver sand transfer paper printing method based on photolithography and film pressing technology comprises the following steps: Step 1: Scan the image. Determine the standard sample of high-shiny silver frosted PET composite paper according to the customer's sample requirements, select a clean, neat and clear sample, and use a high-magnification scanning device to scan the image. Set the resolution to >1200DPI, up to 6000DPI; Step 2: Image processing, layout according to the printing machine width, generally 740*610mm or 730*515mm, and convert the image into a high-resolution digital file; Step three, production of laser engraved nickel plate, selection of nickel plate substrate: use high-purity electrolytic nickel plate (thickness 0.1-0.5mm), the surface must be flat and free of impurities to ensure laser engraving accuracy and electroforming effect. Laser system selection: use fiber laser, wavelength 355nm (ultraviolet), engraving accuracy (5-30μm), working parameters are: power: 10-50W (adjust according to the thickness of the nickel plate to avoid excessive heat affected zone). Scanning speed: 100-2000mm / s, high-speed engraving requires synchronous adjustment of pulse frequency. Focus control: Use dynamic focusing lens to ensure that the laser spot diameter is ≤20μm. Engraving mode: Use vector scanning to directly ablate grooves or microstructures on the nickel surface to form a negative shape of the photolithography pattern. In particular, in order to enhance the final tactile and visual effects of the material, this step requires three or more photolithography superpositions to form a three-dimensional texture effect; The laser engraving parameters were determined through experiments. According to the appearance of the composite material of "Guiyan (hard Xiaoguo wine aroma)", the cell depth was selected to be 5-6um; the screen angle was 45° and the number of screen lines was 200L. The photolithography was superimposed three times, and finally the diffuse reflection effect presented by the original particles coated with high-shiny silver frosted ink was simulated to the maximum extent. Step 4: Imprinting the base film. This step includes conventional PET base film processing. The base film thickness is 14-17um. The processing process includes dust removal and static removal. The end surface is required to be neat, the left and right swing error is ≤1.0-1.5mm, and the winding tension is stable. After coating the peeling layer, glue layer and UV transparent coating, it is immediately compounded with the nickel plate with a pressure of 1.5-2.5kg. After baking in a UV curing machine, it is immediately peeled off to obtain a PET base film with an uneven surface; Step 5, feeding the PET base film in step 4 into a high vacuum winding aluminum coating machine for aluminum coating; Step 6: Transfer the vacuum aluminum-plated PET film to the paper. The film surface glue is coated with an anilox roller. The glue is water-based transfer glue with a solid content of >40% and a transfer amount of 4.5-6.0g / ㎡. The composite transfer pressure is 2.0-3.0kg, the printing roll tension is 5.0-7.5kg, and the drying temperature is 95-110℃. Step 7, process treatment. Compared with the conventional transfer printing process, in order to protect the photolithographic surface image and increase the adhesion of the printing ink, the printed surface after transfer needs to be coated with a special varnish. The varnish used in this case is a colorless transparent liquid with a viscosity of 18-25 seconds. It can enhance the surface tension and diffuse reflection effect of the material and reduce color difference. In order to protect the transfer paper from absorbing moisture / losing water during production, a back coating process is added to ensure that the printing layer is uniform and flat to avoid warping problems; Step 8, in-line printing production, compared with the original PET composite material, the main pattern printing of high-shiny silver frosted transfer paper requires high-hiding and high-transparency inks with large differences in hiding power to highlight the appearance of the product.

[0014] The present invention provides a printing process of a high-shiny silver frosted transfer base paper based on photolithography and film pressing technology, which can ensure that the trademark has the appearance effect of a high-shiny silver frosted composite material and effectively avoid all the shortcomings of the composite material. The specific process is to scan the appearance effect of the high-speed bright silver frosted PET composite paper through a high-power scanner (1200dpi) to obtain a fine picture, and then make a plate according to the printing width (740*610mm or 730*515mm) to obtain a laser engraved nickel plate, and then coat the PET base film with a UV transparent coating and press it with the nickel plate, and obtain a PET base film layout with a high-shiny silver frosted particle concave and convex shape under ultraviolet light curing, and finally use a film pressing composite transfer process to obtain a transfer base paper with a high-shiny silver frosted transfer structure laser diffuse reflection effect, and then combine it with a primer varnish and a back coating protection to realize in-line printing production, replacing the traditional printing process of high-shiny silver frosted PET composite materials.

[0015] In summary, the cost of the printing process of the high-shiny silver frosted transfer backing paper using the photolithography and film pressing technology of the present invention retains the advantages of the original process and also has the following beneficial effects: 1) Since the pictures are converted into high-resolution digital files using CAD or vector software, the color difference of the entire batch of paper is △E<1.0. The visual effect is consistent when observed from any angle, eliminating the color difference problem caused by the difference in particles of high-shiny silver frosted ink used in the original process, and the diffuse reflection layer is more uniform and smooth; 2) The trademark material eliminates the PET film, reducing resource waste and the formation of white pollution; 3) The inherent deformation and warping problems of composite paper raw materials are avoided, the controllability of production quality is improved, and the input-output ratio of each batch is increased from the original 85%-90% to 95%-97.5%, which reduces production costs and improves production efficiency.

[0016] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A high-shiny silver sand transfer paper printing method based on photolithography and film pressing technology, characterized in that: The method comprises the following steps: Step 1: Scan the image. Determine the standard sample of high-shiny silver frosted PET composite paper according to the customer's sample requirements, select a clean, tidy and clear sample, and scan the image with a high-magnification scanning device with a resolution greater than 1200DPI and not higher than 6000DPI; Step 2: Process the image and layout it according to the printing width, which is 740*610mm or 730*515mm, and convert the image scanned in step 1 into a high-resolution digital file; Step 3: Laser engraving nickel plate production, nickel plate substrate selection: use high-purity electrolytic nickel plate, the surface must be flat and free of impurities; laser system selection: use fiber laser, wavelength 355nm, engraving accuracy 5-30μm; working parameters: power: 10-50W; scanning speed: 100-2000mm / s, high-speed engraving requires synchronous adjustment of pulse frequency; focus control: use dynamic focusing lens to ensure that the laser spot diameter is ≤20μm; engraving mode: directly ablate grooves or microstructures on the nickel surface through vector scanning to form the uneven shape of the photolithography pattern; Step 4: Imprint the base film, select the PET base film with a thickness of 14-17um, and process the PET base film. The processing process includes dust removal and static removal. The dust removal operation is to directly adhere large particles on the surface of the base film through a sticky roller, and use high-speed airflow to blow away loose particles. The air knife angle is 30°~45°; at the same time, the ionized airflow neutralizes static electricity; the cleaning speed is synchronized with the production line speed; the roll feeding requires the end face to be neat, the left and right swing error is ≤1.0-1.5mm, and the winding tension is stable; the PET base film is coated with a peeling layer, a glue layer and a UV transparent coating in sequence through multiple groups of coating rollers, and then immediately compounded with a nickel plate before the UV transparent coating dries, with a pressure of 1.5-2.5kg, and baked and dried by a UV curing machine, and then peeled off to obtain a PET base film with an uneven surface; this step realizes the microscopic multi-faceted three-dimensional structure of a high-shiny silver sand digital graphic image; Step 5: Send the PET base film in step 4 to a high vacuum winding aluminum plating machine for aluminum plating to increase the apparent metal effect of the product; Step 6: Compound and transfer the vacuum aluminum-plated PET base film to the paper. The film surface glue is coated with an anilox roller. The PET base film and the composite paper are separated from the peeling layer. The glue layer, the aluminum-plated layer and the UV transparent coating containing a microscopic multi-faceted three-dimensional structure are transferred to the surface of the paper to achieve transfer and deplasticization treatment respectively. Step 7: Processing: Apply special varnish to the printed surface after transfer. The special varnish is a colorless transparent liquid, measured with a Zain No. 3 cup, with a standard viscosity of 18-25S; At the same time, the back of the paper is back-coated, with a back-coating liquid solid content of 25-30%, measured by Caien No. 3 cup, and a standard viscosity of 17-20S; Step 8: In-line printing production, the paper processed in step 7 is printed in-line.

2. The high-shining silver sand transfer paper printing method based on photolithography and film pressing technology according to claim 1 is characterized in that: The thickness of the electrolytic nickel plate is 0.1-0.5mm.

3. A high-shiny silver sand transfer backing paper printing method based on photolithography and film pressing technology according to claim 1 or 2, characterized in that: In step 3, the laser engraved nickel plate is made by at least three times of photolithography superposition to form a three-dimensional texture effect.

4. A high-shiny silver sand transfer backing paper printing method based on photolithography and film pressing technology according to claim 1 or 2, characterized in that: The glue in step six is ​​water-based transfer glue, with a solid content of >40% and a transfer amount of 4.5-6.0 g / ㎡; the composite transfer pressure is 2.0-3.0 kg, the printing roll tension is 5.0-7.5 kg, and the drying temperature is 95-110°C.

5. The high-shiny silver sand transfer backing paper printing method based on photolithography and film pressing technology according to claim 1 or 2, characterized in that: In step eight, the inks required for printing the main pattern produced by the online printing are matte inks and highly transparent inks with strong contrast, and the relative contrast coefficient is greater than 60%, so as to increase the contrast effect of the product.

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