A preparation method of micro-prismatic pattern anti-counterfeiting film and anti-counterfeiting film

Abstract

The invention belongs to the technical field of micro-prismatic anti-counterfeiting films, and specifically relates to a preparation method of a micro-prismatic pattern anti-counterfeiting film and the anti-counterfeiting film. A micro-prismatic layer is flatly spread with a reflective resin liquid, the reflective resin liquid includes nano-scale metal particles with positive charge, and a parallel electric field causes the metal particles to move toward a molded surface of the micro-prismatic layer; a reflective layer is formed through photocuring; glue is coated on a molded surface filling layer of the micro-prismatic layer, a transparent base film with a holographic anti-counterfeiting pattern is bonded to the reflective film, and the micro-prismatic pattern anti-counterfeiting film is prepared; the nano-scale metal particles with positive charge dispersed in the reflective resin liquid are directed to move toward a lower metal plate through a parallel electric field formed between two metal plates, so that the nano-scale metal particles are gathered on the molded surface of the micro-prismatic layer; and a reflective layer is formed through photocuring without using a vapor deposition method, and the reflective layer and the molded surface filling layer of the micro-prismatic layer are formed simultaneously. The method has the advantages of simple method, low production cost and high production efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-prismatic anti-counterfeiting films, and in particular relates to a preparation method of a micro-prismatic pattern anti-counterfeiting film and the anti-counterfeiting film. Background Art

[0002] In order to improve the anti-counterfeiting property of anti-counterfeiting films, the prior art uses micro-prismatic reflective technology, which usually forms a pattern or shape composed of micro-prismatic units on a base film, and then evaporates a metal reflective layer on the surface of the micro-prismatic units. In order to protect the metal reflective layer and make the micro-prismatic units flat, a layer of resin needs to be coated, and then a holographic imaging layer and a sealing layer can be formed in sequence. However, the method of evaporating a metal reflective layer on the surface of a micro-prismatic unit has the problems of high production cost and strict preparation conditions, as well as long preparation time for the evaporation equipment and the evaporation process, and low production efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing a micro-prismatic anti-counterfeiting film and the anti-counterfeiting film, thereby reducing production costs and improving production efficiency.

[0004] The present invention provides a method for preparing a micro-prismatic anti-counterfeiting film, comprising the following steps:

[0005] Spreading transparent resin liquid in the mold cavity, curing it to form a micro-prism layer, and then removing it from the mold;

[0006] The micro-prism layer is placed with the molded surface facing upwards and is flatly spread with a reflective resin liquid, wherein the reflective resin liquid includes dispersed positively charged nano-scale metal particles, a metal plate is respectively arranged on the upper and lower sides of the micro-prism layer, and a voltage is applied between the two metal plates, so that the lower metal plate is positively charged and the upper metal plate is negatively charged, thereby forming a parallel electric field, and causing the positively charged nano-scale metal particles to move toward the molded surface of the micro-prism layer;

[0007] Afterwards, a reflective layer and a surface filling layer of the micro-prism layer are formed on the surface of the micro-prism layer through photocuring to obtain a reflective film;

[0008] Then, a transparent base film is taken, and a holographic anti-counterfeiting pattern is prepared on the transparent base film to obtain a holographic anti-counterfeiting layer, and then the holographic anti-counterfeiting layer is compounded with a reflective film to obtain a micro-prismatic pattern anti-counterfeiting film; or, a holographic anti-counterfeiting pattern is directly prepared on the side of the reflective film away from the mold filling layer to obtain a micro-prismatic pattern anti-counterfeiting film.

[0009] Optionally, the method for preparing the holographic anti-counterfeiting pattern is to directly prepare the holographic anti-counterfeiting pattern on the transparent base film by one of UV lithography, screen printing, roller printing, and laser engraving. A master plate may be prepared by UV lithography or laser engraving first, and then the holographic anti-counterfeiting pattern is prepared on the transparent base film by laminating the master plate. Furthermore, a specific anti-counterfeiting pattern may be formed on the transparent base film by inkjet printing.

[0010] Optionally, the positive pole of a DC power source is connected to the upper metal plate, and the negative pole of a DC power source is connected to the lower metal plate, the potential difference between the two metal plates is 2-10 kV, and the distance between the two metal plates is 10-55 cm.

[0011] Optionally, the area of ​​adjacent sides of the two metal plates is 2-5 times the area of ​​the microprism layer.

[0012] Optionally, the parallel electric field acts for 2-10 minutes.

[0013] Optionally, the micro-prism layer has a flat edge. After the micro-prism layer is separated from the mold, the micro-prism layer is firstly fixed flatly on the clamping member, and then the reflective resin liquid is spread flatly on the micro-prism layer.

[0014] Optionally, after the micro-prism layer is fixed on the clamping member and covered with reflective resin liquid, multiple layers are stacked between two metal plates.

[0015] Optionally, the clamping member includes a bottom plate for supporting the micro-prismatic layer and a frame pressing plate arranged on the top surface of the bottom plate, and the bottom plate and the frame pressing plate are connected and cooperated with each other through bolts to clamp the edge of the micro-prismatic layer.

[0016] Optionally, the reflective resin liquid includes the following components in parts by weight:

[0017] 30-80 parts of polyurethane acrylate, 0.1-5 parts of nano-scale metal particles, 0.5-2 parts of UV curing agent, 0.5-5 parts of leveling agent and 1-5 parts of quaternary ammonium salt cationic surfactant.

[0018] Optionally, the nano-scale metal particles are one or more of nano-gold powder, nano-silver powder, nano-aluminum powder, nano-zinc powder and nano-copper powder.

[0019] Optionally, the particle size of the nano-gold powder is 20 nm, the particle size of the nano-silver powder is 25 nm, the particle size of the nano-aluminum powder is 30 nm, the particle size of the nano-zinc powder is 50 nm, and the particle size of the nano-copper powder is 20 nm.

[0020] Optionally, the UV curing agent is diphenyliodonium hexafluorophosphate or UV-184, the leveling agent is BYK-333, and the quaternary ammonium salt cationic surfactant is dodecyldimethylbenzylammonium chloride or hexadecyltrimethylammonium chloride.

[0021] Optionally, the method for preparing the reflective resin liquid comprises the following steps:

[0022] In parts by weight, nano-scale metal particles, UV curing agent, leveling agent and quaternary ammonium salt cationic surfactant are first added to an organic solvent and stirred and dispersed, and then polyurethane acrylate is added and mixed evenly. The organic solvent is one or more combinations of anhydrous ethanol, anhydrous n-propanol and n-butanol.

[0023] An anti-counterfeiting film is prepared by adopting the preparation method of the micro-prismatic pattern anti-counterfeiting film.

[0024] The beneficial effects of the present invention are that, through the parallel electric field formed between the two metal plates, the nano-scale metal particles with positive charges dispersed in the reflective resin liquid are directed to move toward the metal plate below, so that the nano-scale metal particles are gathered on the mold surface of the micro-prism layer, and then the reflective layer is formed through photocuring without using the evaporation method, and the reflective layer and the mold surface filling layer of the micro-prism layer are formed at the same time, which has the advantages of simple method, low production cost and high production efficiency; in addition, the method of preparing the micro-prism pattern anti-counterfeiting film by directly preparing the holographic anti-counterfeiting pattern on the side of the reflective film away from the mold surface filling layer further simplifies the process steps and improves the production efficiency.

[0025] In the process of preparing the microprismatic pattern anti-counterfeiting film, a reflective layer can be formed on multiple microprismatic layers at the same time, which greatly improves the production efficiency; by adding metal powders of different types and proportions, the reflective film can reflect a special brilliance, which is beneficial to enhance the anti-counterfeiting property of the anti-counterfeiting film. However, it is difficult to prepare such a reflective film using the existing vapor deposition method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the preparation principle of the reflective layer provided in Example 1 of the present invention;

[0027] Figure 2 A schematic diagram of the preparation principle of the reflective layer provided in Example 3 of the present invention;

[0028] Figure 3 This is a schematic structural diagram of the micro-prismatic anti-counterfeiting film provided in Example 1 of the present invention.

[0029] In the figure: 10, microprism layer; 11, reflective layer; 12, profile filling layer; 13, holographic anti-counterfeiting layer; 20, clamping part; 31, metal plate; 32, DC power supply. DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing a micro-prismatic anti-counterfeiting film, comprising the following steps:

[0031] Spreading transparent resin liquid in the mold cavity, curing it to form a micro-prism layer 10, and then removing it from the mold;

[0032] The micro-prism layer 10 is placed with its molded surface facing upwards and is flatly covered with a reflective resin liquid, wherein the reflective resin liquid includes dispersed positively charged nano-scale metal particles. A metal plate 31 is respectively arranged on the upper and lower sides of the micro-prism layer 10, and a voltage is applied between the two metal plates 31, so that the lower metal plate 31 is positively charged and the upper metal plate 31 is negatively charged, thereby forming a parallel electric field, so that the positively charged nano-scale metal particles move toward the molded surface of the micro-prism layer 10;

[0033] Afterwards, a reflective layer 11 is formed on the surface of the micro-prism layer 10 through photocuring to obtain a reflective film;

[0034] Then, a transparent base film is taken, and a holographic anti-counterfeiting pattern is prepared on the transparent base film to form a holographic anti-counterfeiting layer 13. Subsequently, glue is applied on the surface filling layer 12 of the microprism layer 10, and the transparent base film with the holographic anti-counterfeiting pattern is bonded to the reflective film to obtain a microprism pattern anti-counterfeiting film.

[0035] Compared with the prior art, the preparation method of the micro-prismatic pattern anti-counterfeiting film provided by the present invention uses a parallel electric field formed between two metal plates 31 to make the nano-scale metal particles with positive charge dispersed in the reflective resin liquid move toward the metal plate 31 below, so that the nano-scale metal particles are gathered on the surface of the micro-prismatic layer 10, and then form the reflective layer 11 through photocuring without using the evaporation method, and the reflective layer 11 and the surface filling layer 12 of the micro-prismatic layer 10 are formed at the same time, which has the advantages of simple method, low production cost and high production efficiency; in addition, the method of preparing the micro-prismatic pattern anti-counterfeiting film by directly preparing the holographic anti-counterfeiting pattern on the side of the reflective film away from the surface filling layer 12 further simplifies the process steps and improves the production efficiency.

[0036] Example 1

[0037] Preparation of reflective resin liquid:

[0038] In parts by weight, first, stir and disperse 2 parts of nano-scale silver powder, 1 part of diphenyliodonium hexafluorophosphate, 1 part of BYK-333, 1.5 parts of dodecyl dimethyl benzyl ammonium chloride and 30 parts of anhydrous isopropyl alcohol for 5 minutes; then add 35 parts of polyurethane acrylate, continue stirring for 10 minutes to mix evenly, and dodecyl dimethyl benzyl ammonium chloride makes the nano-scale silver powder have a positive charge.

[0039] Preparation of micro-prismatic anti-counterfeiting film:

[0040] Pour polyester acrylate into the mold cavity and flatten it, and form a micro-prism layer 10 after UV light curing. After leaving the mold, the micro-prism layer 10 is flatly fixed on the clamping member 20, with the mold surface of the micro-prism layer 10 facing upward, and then pour the above-mentioned reflective resin liquid and scrape it flat for self-leveling. A metal plate 31 is respectively arranged on the upper and lower sides of the micro-prism layer 10, and the positive pole of the DC power supply 32 is connected to the upper metal plate 31, and the negative pole of the DC power supply 32 is connected to the lower metal plate 31. The potential difference between the two metal plates 31 is 2kV, and the distance between the two metal plates 31 is 12cm, forming a parallel electric field, so that the nano-scale silver particles with positive charge move to the mold surface of the micro-prism layer 10, and the action time is 5min; thereafter, after UV light curing, a reflective layer 11 and a mold surface filling layer 12 of the micro-prism layer 10 are formed on the mold surface of the micro-prism layer 10, and a reflective film is obtained, such as Figure 1 The preparation principle diagram of the light reflecting layer 11 is shown;

[0041] Then, a TPU transparent base film is taken, and a lamination roller is used to laminarize the TPU transparent base film, and a holographic pattern is embossed onto the TPU transparent base film. The molding temperature is 80° C., and the molding speed is 36 m / min. A holographic anti-counterfeiting pattern is prepared on the transparent base film to obtain a holographic anti-counterfeiting layer 13. Subsequently, glue is applied on the side of the reflective film away from the mold surface filling layer 12, and then the holographic anti-counterfeiting layer 13 is bonded and compounded with the reflective film to obtain a micro-prismatic pattern anti-counterfeiting film, the structure of which is as follows: Figure 3 As shown in the figure, the thickness of the TPU transparent base film is 20 μm, and the thickness of the micro-prismatic pattern anti-counterfeiting film is 162 μm.

[0042] Example 2

[0043] Preparation of reflective resin liquid:

[0044] In parts by weight, first, stir and disperse 2 parts of nano-scale silver powder, 1 part of diphenyliodonium hexafluorophosphate, 1 part of BYK-333, 2 parts of dodecyl dimethyl benzyl ammonium chloride and 30 parts of anhydrous isopropyl alcohol for 5 minutes; then add 35 parts of polyurethane acrylate, continue stirring for 10 minutes to mix evenly, and dodecyl dimethyl benzyl ammonium chloride makes the nano-scale silver powder have a positive charge.

[0045] Preparation of micro-prismatic anti-counterfeiting film:

[0046] Pour polyester acrylate into the mold cavity and flatten it, and form a micro-prism layer 10 after UV light curing. After leaving the mold, the micro-prism layer 10 is flatly fixed on the clamping member 20, with the mold surface of the micro-prism layer 10 facing upward, and then pour the above-mentioned reflective resin liquid and scrape it flat for self-leveling. A metal plate 31 is respectively arranged on the upper and lower sides of the micro-prism layer 10, and the positive electrode of the DC power supply 32 is connected to the upper metal plate 31, and the negative electrode of the DC power supply 32 is connected to the lower metal plate 31. The potential difference between the two metal plates 31 is 2kV, and the distance between the two metal plates 31 is 10cm, so as to form a parallel electric field, so that the nano-scale silver particles with positive charge move to the mold surface of the micro-prism layer 10, and the action time is 5min; thereafter, after UV light curing, a reflective layer 11 and a mold surface filling layer 12 of the micro-prism layer 10 are formed on the mold surface of the micro-prism layer 10 to obtain a reflective film;

[0047] Then, a TPU transparent base film is taken, and a lamination roller is used to laminarize the TPU transparent base film, and a holographic pattern is embossed onto the TPU transparent base film. The molding temperature is 80°C, and the molding speed is 36 m / min. A holographic anti-counterfeiting pattern is prepared on the transparent base film to obtain a holographic anti-counterfeiting layer 13. Subsequently, glue is applied on the side of the reflective film away from the mold surface filling layer 12, and then the holographic anti-counterfeiting layer 13 is bonded and compounded with the reflective film to obtain a micro-prismatic pattern anti-counterfeiting film. The thickness of the TPU transparent base film is 20 μm, and the thickness of the micro-prismatic pattern anti-counterfeiting film is 166 μm.

[0048] Example 3

[0049] Preparation of reflective resin liquid:

[0050] In parts by weight, first stir and disperse 1 part of nano-grade gold powder, 3 parts of nano-grade zinc powder, 42 parts of UV-18, 32 parts of BYK-33, 3 parts of hexadecyltrimethylammonium chloride and 60 parts of anhydrous ethanol for 15 minutes; then add 75 parts of polyurethane acrylate and continue stirring for 20 minutes to mix evenly. Dodecyldimethylbenzylammonium chloride makes the nano-grade silver powder have a positive charge.

[0051] Preparation of micro-prismatic anti-counterfeiting film:

[0052] Pour polyester acrylate into the mold cavity and flatten it. After UV curing, form a micro-prism layer 10. After leaving the mold, flatten and fix the micro-prism layer 10 on the clamping member 20 with the molded surface facing upward. Then pour the reflective resin liquid and scrape it flat to form a self-leveling layer. Figure 2As shown, three clamping members 20 are stacked and assembled together and fixed between two upper and lower metal plates 31. The positive electrode of a DC power supply 32 is connected to the upper metal plate 31, and the negative electrode of the DC power supply 32 is connected to the lower metal plate 31. The potential difference between the two metal plates 31 is 5 kV, and the distance between the two metal plates 31 is 25 cm, forming a parallel electric field, so that the nano-scale silver particles with positive charges move toward the mold surface of the micro-prism layer 10, and the action time is 6 minutes; thereafter, a reflective layer 11 and a mold surface filling layer 12 of the micro-prism layer 10 are formed on the mold surface of the micro-prism layer 10 through UV light curing, thereby obtaining a reflective film;

[0053] Then, a TPU transparent base film is taken, and a lamination roller is used to laminarize the TPU transparent base film, and a holographic pattern is embossed onto the TPU transparent base film. The molding temperature is 80°C, and the molding speed is 36 m / min. A holographic anti-counterfeiting pattern is prepared on the transparent base film to obtain a holographic anti-counterfeiting layer 13. Subsequently, glue is applied on the side of the reflective film away from the mold surface filling layer 12, and then the holographic anti-counterfeiting layer 13 is bonded and compounded with the reflective film to obtain a micro-prismatic pattern anti-counterfeiting film. The thickness of the TPU transparent base film is 20 μm, and the average thickness of the micro-prismatic pattern anti-counterfeiting film is 163 μm.

[0054] Example 4

[0055] Preparation of micro-prismatic anti-counterfeiting film:

[0056] Pour polyester acrylate into the mold cavity and flatten it, and form a micro-prism layer 10 after UV light curing. After leaving the mold, the micro-prism layer 10 is flatly fixed on the clamping member 20, with the mold surface of the micro-prism layer 10 facing upward, and then pour the above-mentioned reflective resin liquid and scrape it flat for self-leveling. A metal plate 31 is respectively arranged on the upper and lower sides of the micro-prism layer 10, and the positive electrode of the DC power supply 32 is connected to the upper metal plate 31, and the negative electrode of the DC power supply 32 is connected to the lower metal plate 31. The potential difference between the two metal plates 31 is 2kV, and the distance between the two metal plates 31 is 12cm, so as to form a parallel electric field, so that the nano-scale silver particles with positive charge move to the mold surface of the micro-prism layer 10, and the action time is 5min; thereafter, after UV light curing, a reflective layer 11 and a mold surface filling layer 12 of the micro-prism layer 10 are formed on the mold surface of the micro-prism layer 10, so as to obtain a reflective film;

[0057] Then, a lamination roller was used to laminarize the side of the reflective film that was away from the mold surface filling layer 12, and the holographic pattern was embossed onto the TPU transparent base film. The molding temperature was 80°C, and the molding speed was 36 m / min. A holographic anti-counterfeiting pattern was prepared on the side of the reflective film that was away from the mold surface filling layer 12, and a micro-prismatic pattern anti-counterfeiting film was prepared. The thickness of the micro-prismatic pattern anti-counterfeiting film was 128 μm.

[0058] Comparative Example 1

[0059] Preparation of micro-prismatic anti-counterfeiting film:

[0060] Polyester acrylate is poured into the mold cavity and flattened, and a micro-prism layer 10 is formed after UV light curing. After being separated from the mold, the micro-prism layer 10 is flatly fixed on the clamping member 20, with the mold surface of the micro-prism layer 10 facing upward, and then the reflective resin liquid prepared in Example 1 is poured on it and scraped and self-leveled. A metal plate 31 is respectively arranged on the upper and lower sides of the micro-prism layer 10, and the positive electrode of the DC power supply 32 is connected to the upper metal plate 31, and the negative electrode of the DC power supply 32 is connected to the lower metal plate 31. The potential difference between the two metal plates 31 is 1.5 kV, and the distance between the two metal plates 31 is 12 cm, so that a parallel electric field is formed, so that the nano-scale silver particles with positive charge move toward the mold surface of the micro-prism layer 10, and the action time is 5 minutes; thereafter, a reflective layer 11 and a mold surface filling layer 12 of the micro-prism layer 10 are formed on the mold surface of the micro-prism layer 10 through UV light curing, and a reflective film is obtained; the rest is the same as Example 1.

[0061] Comparative Example 2

[0062] Preparation of micro-prismatic anti-counterfeiting film:

[0063] Pour polyester acrylate into the mold cavity and spread it flat, and form a micro-prism layer 10 after UV light curing. After leaving the mold, the micro-prism layer 10 is flatly fixed on the clamping member 20 with the molded surface of the micro-prism layer 10 facing upward, and then pour the reflective resin liquid prepared in Example 1 and scrape it flat to make it self-leveling, and leave it for 5 minutes; thereafter, it is cured by UV light to obtain a reflective film; the rest is the same as Example 1.

[0064] Comparative Example 3

[0065] Preparation of reflective resin liquid: In parts by weight, first stir and disperse 2 parts of nano-scale silver powder, 1 part of diphenyliodonium hexafluorophosphate, 1 part of BYK-333, 0.6 parts of dodecyl dimethyl benzyl ammonium chloride and 30 parts of anhydrous isopropyl alcohol for 5 minutes; then add 35 parts of polyurethane acrylate and continue stirring for 10 minutes to mix evenly. Dodecyl dimethyl benzyl ammonium chloride makes the nano-scale silver powder have a positive charge.

[0066] The method of Example 1 was adopted to prepare a micro-prismatic anti-counterfeiting film.

[0067] Comparative Example 4

[0068] Preparation of reflective resin liquid: In parts by weight, first stir and disperse 2 parts of nano-scale silver powder, 41 parts of UV-18, 31 parts of BYK-33, 0.6 parts of dodecyl dimethyl benzyl ammonium chloride and 30 parts of anhydrous isopropyl alcohol for 5 minutes; then add 35 parts of polyurethane acrylate and continue stirring for 10 minutes to mix evenly. Dodecyl dimethyl benzyl ammonium chloride makes the nano-scale silver powder have a positive charge.

[0069] The method of Example 1 was adopted to prepare a micro-prismatic anti-counterfeiting film.

[0070] Comparative Example 5

[0071] Preparation of reflective resin liquid: by weight, first stir and disperse 2 parts of nano silver powder, 41 parts of UV-18, 31 parts of BYK-33 and 30 parts of anhydrous isopropyl alcohol for 5 minutes; then add 35 parts of polyurethane acrylate and continue stirring for 10 minutes to mix evenly.

[0072] The method of Example 1 was adopted to prepare a micro-prismatic anti-counterfeiting film.

[0073] Results test:

[0074] The reflectivity of the reflective films of the above embodiments and comparative examples was tested, and the results are shown in Table 1.

[0075] Table 1

[0076]

[0077] From the comparison between the embodiment and comparative examples 1 and 2, it can be seen that the positively charged metal particles need to be aggregated toward the surface of the microprism layer 10 under the action of an electric field, and then photocured to form a reflective layer 11 with good reflectivity, and the intensity of the electric field has a great influence on the quality of the reflective layer 11.

[0078] From Comparative Examples 3 and 5, it can be seen that the quaternary ammonium salt cationic surfactant makes the metal particles carry positive charge, which gathers to the surface of the microprismatic layer 10 under the action of the electric field, and then forms a reflective layer 11 with good reflectivity through photocuring, which is conducive to clearer identification of the prepared microprismatic pattern anti-counterfeiting film.

[0079] It can be seen from Comparative Examples 3 and 4 that diphenyliodonium hexafluorophosphate has the effect of making the metal particles carry positive charges, which can reduce the amount of quaternary ammonium salt cationic surfactants used and improve the reflectivity of the reflective layer 11.

[0080] It can be seen from Example 3 that in the process of preparing the microprismatic pattern anti-counterfeiting film, a reflective layer 11 can be formed simultaneously on multiple microprismatic layers 10, which greatly improves the production efficiency; by adding metal powders of different types and proportions, the reflective film can reflect a special luster, which is beneficial to enhance the anti-counterfeiting property of the anti-counterfeiting film obtained, while it is difficult to prepare such a reflective film using the existing vapor deposition method.

[0081] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0082] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a micro-prismatic anti-counterfeiting film, characterized in that: The following steps are involved: Spreading transparent resin liquid in the mold cavity, curing it to form a micro-prism layer, and then removing it from the mold; The micro-prism layer is placed with the molded surface facing upwards and is flatly spread with a reflective resin liquid, wherein the reflective resin liquid includes dispersed positively charged nano-scale metal particles, a metal plate is respectively arranged on the upper and lower sides of the micro-prism layer, and a voltage is applied between the two metal plates, so that the lower metal plate is positively charged and the upper metal plate is negatively charged, thereby forming a parallel electric field, and causing the positively charged nano-scale metal particles to move toward the molded surface of the micro-prism layer; Afterwards, a reflective layer and a surface filling layer of the micro-prism layer are formed on the surface of the micro-prism layer through photocuring to obtain a reflective film; Then, a transparent base film is taken, and a holographic anti-counterfeiting pattern is prepared on the transparent base film to obtain a holographic anti-counterfeiting layer, and then the holographic anti-counterfeiting layer is compounded with a reflective film to obtain a micro-prismatic pattern anti-counterfeiting film; The micro-prism layer has a flat edge. After the micro-prism layer is separated from the mold, the micro-prism layer is first fixed flatly on the clamping piece, and then the reflective resin liquid is spread on it. After the micro-prism layer is fixed on the clamping piece and spread with the reflective resin liquid, it is stacked in multiple layers between two metal plates.

2. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 1, characterized in that: The positive pole of the DC power supply is connected to the upper metal plate, and the negative pole of the DC power supply is connected to the lower metal plate. The potential difference between the two metal plates is 2-10 kV, and the distance between the two metal plates is 10-55 cm.

3. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 1, characterized in that: The area of ​​the adjacent sides of the two metal plates is 2-5 times the area of ​​the microprism layer.

4. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 1, characterized in that: The reflective resin liquid comprises the following components in parts by weight: 30-80 parts of polyurethane acrylate, 0.1-5 parts of nano-scale metal particles, 0.5-2 parts of UV curing agent, 0.5-5 parts of leveling agent and 1-5 parts of quaternary ammonium salt cationic surfactant.

5. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 4, characterized in that: The nano-scale metal particles are one or more of nano-gold powder, nano-silver powder, nano-aluminum powder, nano-zinc powder and nano-copper powder.

6. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 4, characterized in that: The UV curing agent is diphenyliodonium hexafluorophosphate or UV-184, the leveling agent is BYK-333, and the quaternary ammonium salt cationic surfactant is dodecyl dimethyl benzyl ammonium chloride or hexadecyl trimethyl ammonium chloride.

7. The method for preparing the micro-prismatic anti-counterfeiting film according to claim 4, characterized in that: The method for preparing the reflective resin liquid comprises the following steps: In parts by weight, nano-scale metal particles, UV curing agent, leveling agent and quaternary ammonium salt cationic surfactant are first added to an organic solvent and stirred and dispersed, and then polyurethane acrylate is added and mixed evenly.

8. An anti-counterfeiting film, characterized in that: The anti-counterfeiting film is prepared by the method for preparing the micro-prismatic pattern anti-counterfeiting film according to any one of claims 1 to 3.

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