A method for manufacturing a high-aspect-ratio precision stamping plate with a double-layer microstructure

Abstract

The application belongs to the technical field of gold stamping process, and discloses a manufacturing method of high-depth-width-ratio precision gold stamping plate with double-layer microstructure. A high-depth-width-ratio original plate is printed by high-precision screen printing, screen printing ink is high-brightness thermoplastic ink, the screen printing is pre-cured and in an incomplete curing state, and then the original plate is secondarily molded by high-precision optical molding, the thermoplastic ink is positioned and molded with the high-precision optical molding original plate under heating, a specific microstructure is copied, and finally the original plate is cured under UV light source, the manufacturing of the double-layer structure original plate is completed, the metal nickel plate is copied through the process of silver immersion electroforming, and finally the non-text part is milled by CNC machining, the processing of the high-depth-width-ratio precision gold stamping plate with double-layer microstructure is completed. The pattern effect of the gold stamping plate manufactured by the application has rich pattern level information, can well express the primary and secondary of the image and the bright and dull contrast, the level expression is clear and high in precision, and the anti-fake requirement is met.

Description

Technical Field

[0001] This invention belongs to the field of hot stamping technology, and in particular relates to a method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure. Background Technology

[0002] Hot stamping is a common post-printing process used in packaging, serving as a finishing touch. Traditional hot stamping plates are processed using chemical etching or mechanical engraving methods.

[0003] Traditional etching processes primarily involve etching copper in a solution of hydrogen peroxide and copper trichloride to remove the non-image areas, leaving only the image areas. The main problems with etching are: 1. Difficulty in controlling the etching degree, resulting in poor image precision; the error in etched lines exceeds 0.04mm, making it difficult to create fine lines and prone to breakage; 2. The sloping edges of the etched images can cause smudging during hot stamping; 3. Poor edge smoothness, and the etched plates often have defects due to concentration and material issues; 4. Waste materials pollute the environment.

[0004] Traditional electro-engraving processes primarily use brass as the material. An electro-engraving machine uses a high-speed rotating blade to mill away the non-graphic / text areas. The main problems with electro-engraved plates are as follows: 1. During engraving, the thickness of the lines is determined by the blade. A blade that is too fine is prone to breakage, and a blade that is not fine enough results in thicker lines. Therefore, the finest line thickness in traditional electro-engraving is 0.03mm; 2. During engraving, the blade is conical. Although the tip is fine, the engraving depth is limited. For example, a fine line with a width of 0.03mm can only reach a depth of 0.015mm. It is difficult to achieve a depth-to-width ratio based on the blade height; 3. The edges of the graphics on the engraved plate are rough and uneven, making it difficult to create a mirror-like finish.

[0005] Therefore, the graphic processing of hot stamping plates produced by existing processes is relatively rough, generally consisting of dots, lines, and surfaces. Due to the outdated technology, even the precision of refractive lines can only reach 0.05mm, making it difficult to express the precise effect of graphic images and even more difficult to play a role in anti-counterfeiting.

[0006] In hot stamping, traditional hot stamping creates lines and indentations in a single process. However, due to limitations in precision, it's difficult to accurately represent the effects of hot stamping on graphics and images. Precision hot stamping, on the other hand, can express the light and shadow, layers, and other relationships of an image through changes in microstructure. Therefore, precision hot stamping can solve the problem of low precision in traditional hot stamping. However, precision hot stamping also faces the challenge of expressing the primary and secondary elements and strong contrasts of light and shadow on the same plane through structure, especially when it's difficult to obtain more information from the image at a wide viewing angle. Summary of the Invention

[0007] The purpose of this invention is to provide a method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure, so as to solve the above-mentioned technical problems.

[0008] To solve the above-mentioned technical problems, the specific technical solution of the present invention for a high aspect ratio precision hot stamping plate with a double-layer microstructure is as follows:

[0009] A method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure includes the following steps:

[0010] Step 1: Use vector software to process the hot stamping pattern into a precise line drawing;

[0011] Step 2: Import the precise line drawing vector file into the film printer to output high-precision film;

[0012] Step 3: Select high-mesh screen fabric for exposure with high-precision film;

[0013] Step 4: After stretching the high-mesh screen, apply developing gel and allow it to dry;

[0014] Step 5: Combine the high-precision film and high-mesh screen and expose them to create a high-precision screen printing plate;

[0015] Step 6: Using the high-precision screen printing plate from Step 5, select thermoplastic screen printing ink with low thixotropy to print the pattern on the PET film, and pre-UV cure to form a PET sheet.

[0016] Step 7: Create a high-precision optical molding master;

[0017] Step 8: Position the printed PET sheet with the optical molding original for a second molding, and then perform a second UV curing;

[0018] Step 9: Spray silver onto the PET sheet after secondary molding and electroform it to create a metal plate with a double-layer microstructure.

[0019] Furthermore, the line thickness of the precision line drawing in step 1 is 0.02mm-0.05mm, and the line width to gap ratio is 1:1. This line width to gap ratio is used to change the direction of light.

[0020] Further, in step 3: the high-mesh mesh is made of high-tensile polyester mesh or steel wire mesh, preferably steel wire mesh, and the high-mesh mesh is 420 mesh or higher.

[0021] Furthermore, the formulation of the low-thixotropic thermoplastic screen printing ink in step 6 is as follows: 70% modified polyurethane acrylate; 5-10% TMPTA monomer; 5-8% IBOA monomer; 3-6% benzophenone derivative; 1-2% TPO photoinitiator; 6% active amine; and 1-2% defoaming and leveling agent.

[0022] Furthermore, during printing in step 6, the pressure is 4-6 MPa, and the ink volume is controlled as follows: the squeegee is selected with a hardness of 80 or 90 degrees, the squeegee angle is 90 degrees, the power of the semi-cured UV curing lamp is 8KW, and the paper feed speed during semi-curing is 30 meters per minute.

[0023] Furthermore, the PET film in step 6 is 50µm or larger.

[0024] Furthermore, step 7 includes the following steps:

[0025] Step 7.1: Photolithography is used to photolithographically etch the hot stamping pattern into a photomask with a micro-nano structure image. The depth of the micro-nano structure is 1um-10um. By utilizing the different microstructures, different light sensations and textures are generated through light diffraction. The microstructure is used to express the visual characteristics of the graphic image.

[0026] Step 7.2: Immerse the photomask in silver and electroform it to create a nickel plate, which is the optical molding master.

[0027] Furthermore, step 8 includes the following steps:

[0028] Step 8.1: Accurately register the printed original pattern with the optically molded original;

[0029] Step 8.2: Perform secondary molding and secondary heating curing to form a double-layer original plate. The UV curing lamp for the secondary UV curing is 12KW, and the paper feed speed during the secondary curing is 15 meters per minute.

[0030] Furthermore, step 9 includes the following steps:

[0031] Step 9.1: The PET sheet with the double-layer microstructure pattern is immersed in silver and electroformed to replicate the nickel plate to obtain the hot stamping original;

[0032] Step 9.2: The nickel plate is CNC cut to remove the non-graphic parts, forming a high aspect ratio double-layer precision hot stamping plate.

[0033] The method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to the present invention has the following advantages:

[0034] Traditional precision hot stamping plates, with a depth of 1-2µm, require long setup times and demanding printing conditions during actual printing, resulting in poor brightness of the printed image. The high aspect ratio precision hot stamping plate produced by the method of this invention has a high aspect ratio; the deeper the hot stamping plate, the easier it is to replicate, resulting in a stronger texture and higher brightness in the hot stamping effect.

[0035] The use of thermoplastic screen printing inks is beneficial for mirror replication of microstructures in secondary molding. After mirror molding with a photomask, the microstructures on the surface of the plate achieve a mirror effect, and the finished plate has increased brightness during hot stamping.

[0036] In the secondary molding process, an optical original and a silkscreen PET printing plate are used for secondary positioning molding. The optical microstructure is replicated on the printing plate, which can present a special light and texture and also play an anti-counterfeiting role.

[0037] The plate processing adopts the electroforming replication process, which is convenient and economical. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to the present invention.

[0039] Figure 2 This is a high-precision screen printing pattern for the present invention;

[0040] Figure 3 is a rendering of the original secondary molding plate of the present invention;

[0041] Figure 4 is a schematic diagram of the dual-structure effect of the present invention;

[0042] Figure 5 is a schematic diagram of the secondary molding process of the present invention. Detailed Implementation

[0043] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure.

[0044] This invention discloses a method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure. The method employs high-precision screen printing to create a master plate with a high aspect ratio. The high-precision screen printing lines can reach a thickness of 0.02-0.05 mm, a line width to line spacing ratio of 1:1, and an aspect ratio exceeding 0.8. High-gloss thermoplastic ink is used for screen printing. After screen printing, the ink is pre-cured in an incompletely cured state, followed by a second molding process using a high-precision optical molding master plate. The thermoplastic ink is molded with the high-precision optical molding master plate under heating conditions to replicate a specific microstructure. Finally, the ink is cured under a UV light source to complete the production of the double-layer structure master plate. This is then replicated into a nickel plate through processes such as silver electroforming. Finally, the non-image areas are milled away using CNC machining, completing the processing of the high aspect ratio precision hot stamping plate with a double-layer microstructure.

[0045] like Figure 1 As shown, the specific processing steps of the present invention are as follows:

[0046] Step 1: Use vector software such as AI to process the hot stamping pattern into a precise line drawing. The precise line drawing is used to express the light and shadow layers and three-dimensional structure of the graphic image. The line thickness is 0.02mm-0.05mm, and the line width to gap ratio is 1:1. This line width to gap ratio is used to change the direction of light and achieve effects such as relief and flashing.

[0047] Step 2: Import the vector file (precise line drawing) into the film printer to output a high-precision film; the precision of traditional film printers cannot meet the requirements of this invention, so this invention requires the use of a high-precision film printer to ensure the clarity of the lines.

[0048] Step 3: Select a high-mesh screen for exposure with high-precision film. The aspect ratio is determined by the mesh count and opening rate of the screen. Therefore, high-tensile polyester mesh or steel wire mesh can be selected, preferably steel wire mesh. The high-mesh screen should be 420 mesh or higher, preferably 510 mesh.

[0049] Step 4: After stretching the high-mesh screen, apply developing gel and let it dry.

[0050] Step 5: Combine the high-precision film and high-mesh screen and expose them to create a high-precision screen printing plate.

[0051] Step 6: Using the high-precision screen printing plate from Step 5, select thermoplastic screen printing ink with low thixotropy to print the pattern (original pattern) on the PET film, and pre-UV cure to form a PET sheet. The effect is as follows: Figure 2 As shown.

[0052] The formulation of thermoplastic screen printing ink with low thixotropy is as follows: 70% modified polyurethane acrylate; 5-10% TMPTA monomer; 5-8% IBOA monomer; 3-6% benzophenone derivative; 1-2% TPO photoinitiator; 6% active amine; and 1-2% defoaming and leveling agent.

[0053] During printing, adjust the pressure and ink volume appropriately to ensure clear printing, smooth ink flow without bubbles, and a glossy surface. During curing, the ink should not be fully cured; it should remain in a semi-cured state until it sets, thus serving a shaping function. Preferably, the pressure is 4-6 MPa. Ink volume control methods include selecting a squeegee with a hardness of 80 or 90 and a squeegee angle of 90 degrees. The UV curing lamp power is 8 kW, and the paper feed speed during semi-curing is 30 meters per minute.

[0054] The PET film has a thickness of 50 μm or more, preferably 100 μm.

[0055] Step 7: Create a high-precision optical molding master:

[0056] Step 7.1: Use photolithography to photolithographically etch the hot stamping pattern into a photomask with a micro-nano structure image. The micro-nano structure image includes effects such as relief, laser, holography, or lens, and the depth of the micro-nano structure is between 1um and 10um. By utilizing the different microstructures, different light sensations and textures are generated through light diffraction, and the visual characteristics of the graphic image are expressed by the microstructure.

[0057] Step 7.2: Immerse the photomask in silver and electroform it to create a nickel plate (optical molding original).

[0058] Step 8: Position the printed PET sheet with the optical molding original for a second molding process, and then perform a second UV curing.

[0059] Step 8.1: Accurately register the printed original pattern with the optically molded original;

[0060] Step 8.2: As Figure 5 As shown, a second molding and second heating curing process is performed to form a double-layer original plate. The UV curing lamp for the second UV curing is 12KW, and the paper feed speed during the second curing is 15 meters per minute. The effect is as follows. Figure 3 As shown.

[0061] Step 9: Spray silver onto the PET sheet after secondary molding and electroform it to create a metal plate with a double-layer microstructure.

[0062] Step 9.1: The PET sheet with the double-layer microstructure pattern is impregnated with silver and electroformed to replicate the nickel plate, thus obtaining the hot stamping original; the effect is as follows. Figure 4 As shown.

[0063] Step 9.2: The nickel plate is CNC cut to remove the non-graphic parts, forming a high-depth double-layer precision hot stamping plate.

[0064] During hot stamping, the hot stamping equipment is equipped with a high aspect ratio double-layer precision hot stamping dies prepared in the above steps. Ordinary electroplated aluminum film is then used in a flat-pressing and then pressing manner to complete the hot stamping effect. The hot stamping effect produced using the method of this invention has rich pattern layer information, effectively expressing the primary and secondary elements of the image and strong contrast between light and matte, with clear and high-precision layer expression, and also meets anti-counterfeiting requirements.

[0065] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure, characterized in that, Includes the following steps: Step 1: Use vector software to process the hot stamping pattern into a precise line drawing; Step 2: Import the precise line drawing vector file into the film printer to output high-precision film; Step 3: Select high-mesh screen fabric for exposure with high-precision film; Step 4: After stretching the high-mesh screen, apply developing gel and allow it to dry; Step 5: Combine the high-precision film and high-mesh screen and expose them to create a high-precision screen printing plate; Step 6: Using the high-precision screen printing plate from Step 5, select thermoplastic screen printing ink with low thixotropy to print the pattern on the PET film, and pre-UV cure it. The film is in a semi-cured state until the ink is set, thus forming a PET sheet. The low-thixotropic thermoplastic screen printing ink formulation is as follows: 70% modified polyurethane acrylate; 5-10% TMPTA monomer; 5-8% IBOA monomer; 3-6% benzophenone derivative; 1-2% TPO photoinitiator; 6% active amine; and 1-2% defoaming and leveling agent. The printing pressure is 4-6 MPa. The ink volume control method is as follows: select a squeegee with a hardness of 80 or 90 degrees, a squeegee angle of 90 degrees, a UV curing lamp power of 8KW for semi-curing, and a paper feed speed of 30 meters per minute during semi-curing. Step 7: Create a high-precision optical molding master; Step 7.1: Photolithography is used to photolithographically etch the hot stamping pattern into a photomask with a micro-nano structure image. The depth of the micro-nano structure is 1um-10um. By utilizing the different microstructures, different light sensations and textures are generated through light diffraction. The microstructure is used to express the visual characteristics of the graphic image. Step 7.2: Immerse the photomask in silver and electroform it to create a nickel plate, i.e., the optical molding master plate; Step 8: Position the printed PET sheet with the optical molding original for a second molding, and then perform a second UV curing; Step 8.1: Accurately register the printed original pattern with the optically molded original; Step 8.2: Perform secondary molding and secondary heating curing to form a double-layer structure original. The UV curing lamp for the secondary UV curing is 12KW, and the paper feed speed during the secondary curing is 15 meters per minute. Step 9: Spray silver onto the PET sheet after secondary molding and electroform it to create a metal plate with a double-layer microstructure.

2. The method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to claim 1, characterized in that, The line thickness of the precision line drawing in step 1 is 0.02mm-0.05mm, and the line width to gap ratio is 1:

1. This line width to gap ratio is used to change the direction of light.

3. The method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to claim 1, characterized in that, Step 3: The mesh for high-mesh netting is high-tensile polyester netting or steel wire netting, with a mesh size of 420 mesh or higher.

4. The method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to claim 1, characterized in that, The PET film in step 6 is 50µm or larger.

5. The method for manufacturing a high aspect ratio precision hot stamping plate with a double-layer microstructure according to claim 1, characterized in that, Step 9 includes the following steps: Step 9.1: The PET sheet with the double-layer microstructure pattern is immersed in silver and electroformed to replicate the nickel plate to obtain the hot stamping original; Step 9.2: The nickel plate is CNC cut to remove the non-graphic parts, forming a high-depth double-layer precision hot stamping plate.

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