Anti-counterfeiting flexible packaging bag and preparation method thereof

Abstract

The invention belongs to the technical field of anti-counterfeiting flexible packaging bags, and particularly relates to an anti-counterfeiting flexible packaging bag and a preparation method thereof.A packaging bag body is provided with side organ folding edges and sequentially comprises a base layer, an adhesion layer and an outer covering layer from inside to outside. Hollowed-out parts are arranged on the inner sides of the folded edges of the outer coating layer, and the corresponding adhesion layer contains color-changing substances; a reaction part containing a reaction substance is arranged on the inner side of the folded edge on the opposite side of the hollow part, and a barrier film is coated outside the reaction part. During preparation, the processes of loading the color-changing substance on the adhesion layer, processing the hollow part on the outer coating layer, fixing the reaction part, coating the barrier film, folding, forming and packaging are sequentially completed. During verification, the barrier film is damaged, the reaction substance reacts with the color-changing substance to develop color, and a two-dimensional code is formed through the hollow part for scanning verification. The anti-fake safety is improved, operation is convenient and fast, the side organ folded edges can protect key structures, and the packaging box is suitable for various food packaging scenes.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anti-fake soft packaging bags, and particularly relates to an anti-fake soft packaging bag and a preparation method thereof. BACKGROUND

[0002] At present, the food industry is developing rapidly, and food safety is of great concern to consumers. Traditional food packaging has limited information, making it difficult for consumers to fully understand the true situation of the food and easily doubt the quality. The two-dimensional code with traceability function can allow consumers to conveniently obtain food information, effectively reduce concerns about safety, and thus enhance the willingness to purchase and trust in the brand.

[0003] However, such two-dimensional code digital anti-fake labels have obvious defects. Unscrupulous vendors can copy the corresponding anti-fake labels by scanning a printer, and then sell the counterfeit products with the copied labels, greatly increasing the difficulty of law enforcement and threatening the safety of consumers' lives and property. The anti-fake codes commonly used in the market are printed in plaintext form on the surface of the packaging bag due to cost and ease of production, which are easy to be copied and have low overall anti-fake level. Food packaging bags with anti-fake traceability codes or two-dimensional code functions can effectively prevent counterfeiting and have important significance and role in ensuring food safety, combating counterfeiting and substandard products, optimizing enterprise management and assisting supervision, and have irreplaceable value for promoting the healthy development of the food industry and protecting public food safety. SUMMARY

[0004] The present application aims to provide an anti-fake soft packaging bag and a preparation method thereof to solve the problem of easy copying of two-dimensional code digital anti-fake labels.

[0005] To achieve the above-mentioned purpose, one aspect of the present application provides a technical solution: an anti-fake soft packaging bag, comprising a packaging bag body, the packaging bag body adopts a side organ fold edge, and the packaging bag body is composed of an inner layer, an attached layer and an outer cover layer from inside to outside. The outer cover layer is provided with a hollow part on the inner side of the fold edge. The attached layer corresponding to the hollow part contains a color-changing substance. The hollow pattern corresponds to the color blocks of the identification two-dimensional code. The outer cover layer on the inner side of the fold edge opposite to the hollow part is provided with a reaction part. The reaction part contains a reaction substance that causes the color-changing substance to develop color. The outer surface of the reaction part is covered with a barrier film.

[0006] The working principle and beneficial effects of this solution are as follows: When the packaging bag is unopened, the barrier film on the outer surface of the reaction section acts as an isolation and protection, physically separating the reaction section from the exposed adhesive layer of the perforated section. At this time, the exposed adhesive layer of the perforated section does not change color and remains colorless. When verification of anti-counterfeiting information is required, because the packaging bag uses a side accordion fold, the fold where the reaction section is located corresponds to the fold where the perforated section is located in the sealed state, breaking the barrier film outside the reaction section and allowing the reactive substance in the reaction section to come into contact with the color-changing substance in the adhesive layer. Under the action of the reactive substance, the color-changing substance changes color, revealing a QR code pattern consistent with the preset pattern through the perforated section of the outer layer. Users can scan this QR code and compare it with the information in the database to complete the anti-counterfeiting verification.

[0007] This invention offers the following advantages: First, the QR code is not pre-printed plain text; it requires breaking the barrier film to trigger a reaction and reveal its color, making it difficult to counterfeit an uncolored QR code. Second, consumers can trigger the color reveal simply by pressing and folding the edge, without the need for complex tools, facilitating quick and easy anti-counterfeiting verification while also adding fun. Third, the accordion-folded outer layer provides physical protection for the reaction section and the perforated section located inside the fold. During transportation, storage, and daily handling, the outer layer of the fold can prevent direct friction and collision from external objects, avoiding accidental damage to the barrier film of the reaction section, loss of the reactive substance, or abnormal display of the QR code pattern due to friction deformation of the perforated section, ensuring that the anti-counterfeiting function can be used normally when verification is required.

[0008] Optionally, the cutout pattern of the cutout portion includes a partial identification QR code, and a plain text portion is provided next to the cutout portion, with the remaining identification QR code printed on the plain text portion. The cutout portion and the plain text portion constitute a complete identification QR code.

[0009] Optionally, the outer covering layer consists of an inner and outer covering layer and an outer outer covering layer from the inside to the outside. The hollow part is disposed on the inner and outer covering layers. The hollow pattern of the hollow part includes a partial identification QR code. The outer outer covering layer is provided with a C-shaped tear line. The plain text part is disposed within the part surrounded by the tear line on the inner side of the outer outer covering layer. The hollow part and the plain text part are combined at the connection of the C-shaped tear line to form a complete identification QR code.

[0010] Optionally, the reactant includes weakly alkaline calcium hydroxide, and the colorant includes phenolphthalein. Upon contact, the coating changes from colorless to red. The alkaline substance exhibits strong stability, making it suitable for packaging applications requiring long-term storage.

[0011] Optionally, the reactants include potassium iodate and citric acid, and the color-developing substance includes starch. Upon contact, the coating changes from colorless to blue. All raw materials are food-grade solids, exhibiting high stability and non-volatility, making them suitable for long-term food packaging.

[0012] Optionally, the reaction substance comprises sodium bicarbonate, and the color developing substance comprises anthocyanin. After contact, the adhesive layer changes from colorless or light color to blue or purple. The raw materials are all food-grade solids, non-irritating, and highly safe, suitable for low-temperature or room-temperature food packaging.

[0013] Another aspect of the present application provides a preparation method of the above-mentioned anti-fake soft packaging bag, comprising the following steps: S1: machining a hollow part on the outer cover layer by a laser cutting device, the hollow pattern corresponding to the color block of the identification two-dimensional code; S11: loading the pre-set color changing substance to a partial area of the adhesive layer, and drying the adhesive layer after loading; S12: loading the pre-set reaction substance to a partial area of the outer surface of the outer cover layer to form a reaction part, and then using a wax paper as a barrier film to completely cover the outer surface of the reaction part; S2: sequentially compounding the base layer, the adhesive layer and the outer cover layer from inside to outside, and when compounding, the area of the adhesive layer loaded with the color changing substance overlaps with the hollow part of the outer cover layer; S3: performing side concertina folding processing on the compound film formed after step S2 by a folding edge device, so that the folding edge where the reaction part is located and the folding edge where the hollow part is located are in opposite positions in a natural packaging state; S4: cutting the compound film after folding edge processing in step S3 into single packaging bag blanks by a cutting device, and performing sealing processing on the edges of the packaging bag blanks by a sealing machine.

[0014] Optionally, the reaction substance comprises calcium hydroxide, the calcium hydroxide is mixed with a small amount of food-grade filler to be pressed into a flaky shape and attached to the inner side of the folding edge; the color developing substance comprises phenolphthalein, the phenolphthalein powder is mixed with a food-grade ethanol solution, and after adding an aqueous adhesive, it is coated on the specified area of the adhesive layer by a gravure coating process, and after drying, the ethanol volatilizes to form a colorless solid coating.

[0015] Optionally, the reaction substance comprises potassium iodate and citric acid, the potassium iodate and the citric acid are mixed in a mass ratio of 1:3, a small amount of food-grade carrier is added, and the mixture is attached to the inner side of the folding edge by a dry powder coating process; the color developing substance comprises starch, the starch is mixed with a food-grade adhesive, a slurry is prepared, and the slurry is coated on the specified area of the adhesive layer by a gravure coating.

[0016] Optionally, the reaction substance comprises sodium bicarbonate, the sodium bicarbonate is mixed with a small amount of food-grade filler, pressed into a flaky shape, and attached to the inner side of the folding edge; the color developing substance comprises anthocyanin, the anthocyanin powder is mixed with a food-grade aqueous resin, and coated on the specified area of the adhesive layer by a roller coating process, and after drying, a colorless or light-colored solid coating is formed. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1It is the whole schematic view of a kind of anti-fake soft packing bag in the embodiment one of the present application; Figure 2 It is the schematic view of side organ folding edge in the embodiment one of the present application; Figure 3 It is the schematic view of the hollow part in the embodiment one of the present application; Figure 4 It is the schematic view of the hollow part in the embodiment two of the present application; Figure 5 It is the schematic view of the hollow part in the embodiment three of the present application. DETAILED DESCRIPTION

[0018] It is further detailed by specific implementation in the following: The mark in the drawing of specification includes: packing bag body 1, base layer 11, attached layer 12, outer covering layer 13, inner and outer covering layer 131, outer outer covering layer 132, side organ folding edge 2, hollow part 3, plaintext part 4, reaction part 5, barrier film 6.

[0019] Embodiment one This embodiment is basically as shown in Figure 1 、 2 : a kind of anti-fake soft packing bag, based on the color change system of calcium hydroxide and phenolphthalein, including packing bag body 1, packing bag body 1 adopts side organ folding edge 2, packing bag body 1 is from inside to outside in turn base layer 11, attached layer 12, outer covering layer 13.Base layer 11 selects food-grade polyethylene film, with good sealing property and solvent resistance, for isolating content and outer layer structure.Attached layer 12 selects plant fiber film, attached layer 12 is loaded color developing substance corresponding to the position of the hollow part 3 of outer covering layer 13, color developing substance is phenolphthalein in this embodiment, and forms colorless solid coating by gravure coating process.As shown in Figure 3 , outer covering layer 13 selects polyester film resistant to friction, is provided with the hollow part 3 corresponding to the part color block of identification two-dimensional code in the inside of folding edge, the hollow part 3 connection is equipped with plaintext part 4, plaintext part 4 prints the remaining part of identification two-dimensional code, the hollow part 3 and plaintext part 4 are divided according to the longitudinal axis of identification two-dimensional code, and form complete identification two-dimensional code after combination.Reaction part 5 is located in the inside of folding edge of outer covering layer 13 and the position opposite to hollow part 3, and contains weakly alkaline calcium hydroxide as reactant, the outer surface of reaction part 5 is coated with wax paper as barrier film 6, for isolating reactant and attached layer 12.

[0020] Phenolphthalein is a solid white powder, safe at low doses, is a traditional acid-base indicator; calcium hydroxide is a white powder solid, belongs to food-grade additives, with weak alkaline, stable chemical properties, can be stored for a long time in dry state. In dry state, phenolphthalein solid and calcium hydroxide solid are both colorless, after contact, trace amount of moisture in the air or a small amount of moisture makes a small amount of calcium hydroxide dissolved, the solution is weakly alkaline, phenolphthalein isomerizes under weakly alkaline conditions, from colorless lactone form to red quinone structure, thus showing obvious red color.

[0021] A method for preparing a soft anti-counterfeiting packaging bag, comprising the following sequential steps: S1: selecting a polyester film as the material of the outer cover layer 13, processing the hollow part 3 on the outer cover layer 13 through a laser cutting device, the hollow pattern corresponds to the left half of the color block of the identification two-dimensional code, and the right half of the identification two-dimensional code is printed as the plaintext part 4 beside the hollow part 3 on the surface of the outer cover layer 13.

[0022] S11: selecting a plant fiber film as the material of the attachment layer 12, mixing phenolphthalein powder with a small amount of food-grade ethanol solution, a small amount of ethanol helps the phenolphthalein powder to dissolve, adding 5% of the water-based adhesive polyvinyl alcohol to stir uniformly, coating the mixed solution on the attachment layer 12 through a gravure coating process, and drying after coating to form a colorless solid coating after the complete evaporation of ethanol; S12: mixing calcium hydroxide powder and food-grade calcium carbonate filler according to a mass ratio of 8:2, pressing into a thin sheet, attaching on the outer cover layer 13 through hot melt adhesive to form the reaction part 5, and using wax paper as a barrier layer to completely cover the outer surface of the reaction part 5; S2: sequentially compounding the base layer 11, the attachment layer 12 and the outer cover layer 13 from inside to outside, and loading the color-changing substance to the part of the attachment layer 12 corresponding to the hollow part 3 during compounding; S3: processing the side concertina fold 2 of the composite film formed after S2 through a folding edge device, and ensuring that the fold edge where the reaction part 5 is located and the fold edge where the hollow part 3 is located are in opposite positions in the natural packaging state; S4: cutting the composite film after S3 into a single packaging bag blank through a cutting device, and sealing the edges of the packaging bag blank through a sealing machine.

[0023] When unopened, the barrier film 6 isolates the reaction part 5 from the attachment layer 12, and the hollow part 3 has no color display, and the plaintext part 4 alone cannot form a complete two-dimensional code. When verifying, since the packaging bag adopts the side organ fold edge 2, the fold edge where the reaction part 5 is located corresponds to the fold edge where the hollow part 3 is located in the packaging state. By breaking the wax paper barrier film 6, pressing the fold edge makes the calcium hydroxide in the reaction part 5 contact with the phenolphthalein in the attachment layer 12. The phenolphthalein changes from colorless to red under weak alkaline conditions. The red pattern is displayed through the outer cover layer 13 of the hollow part 3, and combined with the right half of the two-dimensional code of the plaintext part 4 to form a complete identification two-dimensional code. The user scans the complete two-dimensional code to complete the anti-fake verification by comparing with the database.

[0024] The structures such as the hollow part 3, the plaintext part 4, the reaction part 5, and the attachment layer 12 can be processed using existing mature materials, without complex processes, facilitating industrialized production, and without significantly increasing the manufacturing cost of the packaging bag.

[0025] Example Two The difference between this embodiment and Example One is that this embodiment provides an anti-fake soft packaging bag based on the color change system of potassium iodate, citric acid, and starch. The attachment layer 12 adopts non-woven fabric, and the attachment layer 12 loads the color developing substance starch at the position corresponding to the hollow part 3 of the outer cover layer 13 to form a colorless coating layer. As shown in Figure 4 The outer cover layer 13 is provided with a hollow part 3, and the hollow pattern corresponds to all color blocks of the identification two-dimensional code. The reaction part 5 contains the reactants potassium iodate and citric acid, and the mass ratio of potassium iodate to citric acid is 1:3.

[0026] Starch is a white powder solid, food grade, harmless, and widely used in food processing; potassium iodate is a white crystal solid, food grade iodine supplement additive, and citric acid is a white crystal solid, food grade acidity regulator, harmless. In a dry state, starch, potassium iodate, and citric acid are all colorless solids and do not react with each other. When the reaction part 5 contacts with the attachment layer 12 and there is a trace of moisture, the citric acid is dissolved, and an acidic environment is provided after dissolution; the potassium iodate is reduced under acidic conditions to generate free iodine I2; the iodine combines with starch to form a blue complex, realizing the color developing process from colorless to blue.

[0027] A preparation method of an anti-fake soft packaging bag, the difference between this embodiment and Example One is that steps S1 to S12: S1: A laser cutting device is used to process a hollow part 3 on the outer cover layer 13 corresponding to all color blocks of the identification two-dimensional code; S11: The attachment layer 12 adopts non-woven fabric, starch and food grade adhesive carboxymethyl cellulose are mixed in a mass ratio of 3:1 to form a slurry, which is coated on the attachment layer 12 by gravure coating process and then dried; S12: mix potassium iodate and citric acid with a mass ratio of 1:3, add 10% food-grade carrier malt dextrin, and attach it to the outer cover layer 13 by dry powder coating process to form the reaction part 5; When unopened, the barrier film 6 isolates the reaction substance from the attached layer 12, and the hollow part 3 has no color display. When verified, since the packaging bag adopts the side organ fold edge 2, the fold edge where the reaction part 5 is located corresponds to the fold edge where the hollow part 3 is located in the packaging state, the barrier film 6 is damaged, the potassium iodate and citric acid react to generate elemental iodine under the action of a small amount of water, the elemental iodine in the reaction part 5 is contacted with the starch in the attached layer 12 by pressing the fold edge, and the starch coating layer in the attached layer 12 changes from colorless to blue under the action of the elemental iodine, and the blue pattern is displayed through the hollow part 3 to form a complete two-dimensional code, which can be scanned to complete the verification.

[0028] Example three The difference between this embodiment and example one is that this embodiment provides a kind of anti-fake soft packaging bag based on the discoloration system of sodium bicarbonate and anthocyanin. The attached layer 12 loads the color developing substance anthocyanin to form a colorless or light-colored solid coating. As shown in Figure 5 The outer cover layer 13 is composed of inner and outer cover layers 131 and outer outer cover layers 132 from inside to outside, the hollow part 3 is arranged on the inner and outer cover layers 131, the hollow pattern corresponds to the left half of the color block of the identification two-dimensional code, the outer outer cover layer 132 is provided with a C-shaped tear line, the plaintext part 4 is arranged in the part surrounded by the tear line on the inner side of the outer outer cover layer 132, the plaintext part 4 prints the right half of the identification two-dimensional code, and the hollow part 3 and the plaintext part 4 are combined into a complete identification two-dimensional code at the connection of the C-shaped tear line. The reaction part 5 contains the reaction substance sodium bicarbonate.

[0029] Anthocyanin is a light-colored powder solid, such as purple cabbage extract, grape skin extract, natural pigment, harmless, and has antioxidant properties; sodium bicarbonate is a white crystalline solid, a food-grade leavening agent, commonly known as baking soda, harmless. In dry state, sodium bicarbonate is colorless, and anthocyanin is light-colored or colorless in acidic or neutral dry environment. After contact, a small amount of water makes sodium bicarbonate dissolve and release OH⁻, forming a weak alkaline environment, and the molecular structure of anthocyanin changes under alkaline conditions, changing from light color / colorless to blue or purple, such as purple cabbage anthocyanin showing blue, grape skin anthocyanin showing purple.

[0030] A kind of preparation method of anti-fake soft packaging bag, the difference between this embodiment and example one is that steps S1 to S12: S1: the outer cover layer 13 is composed of inner and outer cover layers 131 and outer outer cover layers 132 from inside to outside, the inner and outer cover layers 131 are processed by laser cutting equipment to form the hollow part 3, the hollow pattern corresponds to the left half of the color block of the identification two-dimensional code, the outer outer cover layer 132 is processed by die cutting equipment to form a C-shaped tear line, the right half of the identification two-dimensional code is printed in the part surrounded by the tear line as the plaintext part 4, and dried and solidified after printing; S11: mixing anthocyanin powder with food-grade aqueous resin polyvinyl alcohol at a mass ratio of 1:5, coating on the adhesive layer 12 by roller coating process, and then drying; S12: mixing sodium bicarbonate with a small amount of food-grade filler corn starch, pressing into a sheet, and attaching on the outer cover layer 13 by hot melt adhesive to form the reaction part 5, and using wax paper as the barrier film 6 to completely cover the outer surface of the reaction part 5.

[0031] When not opened, the barrier film 6 prevents the reaction from occurring, and the hollow part 3 has no obvious color. When verified, the outer cover layer 132 is torn along the C-shaped tear line, exposing the hollow part 3 of the inner and outer cover layer 131 and the plaintext part 4 of the outer layer. Since the packaging bag uses a side organ fold 2, the fold where the reaction part 5 is located corresponds to the fold where the hollow part 3 is located in the packaging state, the barrier film 6 is damaged, the reaction part 5 is dipped in a small amount of moisture, and the sodium bicarbonate of the reaction part 5 is pressed to contact the anthocyanin of the adhesive layer 12. Under weak alkaline conditions, anthocyanin changes from colorless or light color to blue or purple, which is visible through the hollow part 3, and the plaintext part 4 is combined to form a complete two-dimensional code at the tear-off place, which can be scanned to verify the anti-counterfeiting information.

[0032] The above is only an embodiment of the present application, which is not limited to this embodiment. The specific structure and characteristics of the scheme and other common knowledge are not described in detail here. The ordinary skilled person in the art knows all the ordinary technical knowledge in the field of the invention before the filing date or the priority date, can know all the prior art in this field, and has the ability to apply conventional experimental means before that date. The ordinary skilled person in the art can improve and implement this scheme based on their own ability under the guidance of this application. Some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement this application. It should be noted that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be considered as the protection scope of the present application. These will not affect the effect and practicality of the patent. The protection scope of this application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A type of anti-counterfeiting flexible packaging bag, characterized in that: The product includes a packaging bag body with a side accordion fold. From the inside out, the packaging bag body consists of a base layer, an attachment layer, and an outer covering layer. The outer covering layer has a perforated section located inside the fold. The attachment layer corresponding to the perforated section contains a color-changing substance. The perforated pattern corresponds to the color block of the QR code. The outer covering layer corresponding to the perforated section inside the fold has a reaction section containing a reactive substance that makes the color-changing substance develop color. The outer surface of the reaction section is covered with a barrier film.

2. The anti-counterfeiting flexible packaging bag according to claim 1, characterized in that: The hollowed-out pattern of the hollowed-out part includes a partial identification QR code, and a plain text part is provided next to the hollowed-out part, on which the remaining identification QR code is printed. The hollowed-out part and the plain text part constitute a complete identification QR code.

3. The anti-counterfeiting flexible packaging bag according to claim 2, characterized in that: The outer covering consists of an inner and outer covering and an outer outer covering from the inside out. The hollow part is set on the inner and outer coverings. The hollow pattern of the hollow part includes a partial identification QR code. The outer outer covering has a C-shaped tear line. The plain text part is set in the part surrounded by the tear line on the inner side of the outer outer covering. The hollow part and the plain text part are combined at the connection of the C-shaped tear line to form a complete identification QR code.

4. The anti-counterfeiting flexible packaging bag according to claim 1, characterized in that: The reactants include weakly alkaline calcium hydroxide, and the colorimetric substance includes phenolphthalein.

5. The anti-counterfeiting flexible packaging bag according to claim 1, characterized in that: The reactants include potassium iodate and citric acid, and the colorimetric substance includes starch.

6. The anti-counterfeiting flexible packaging bag according to claim 1, characterized in that: The reactants include sodium bicarbonate, and the colorant includes anthocyanins.

7. A method for preparing an anti-counterfeiting flexible packaging bag, characterized in that: Includes the following steps: S1: A hollowed-out section is processed on the outer coating using laser cutting equipment, and the hollowed-out pattern corresponds to the color block of the QR code for recognition; S11: Load the preset color-changing substance onto a portion of the adhesion layer, and dry the adhesion layer after loading is complete; S12: Load the preset reactant onto a portion of the outer surface of the outer coating to form a reaction section, and then use wax paper as a barrier film to completely cover the outer surface of the reaction section. S2: The base layer, the adhesive layer and the outer layer are compounded in the order from the inside to the outside. During the compounding process, the area where the color-changing material is loaded onto the adhesive layer overlaps with the perforated part of the outer layer. S3: The composite film formed after step S2 is folded using a folding device to make the folded edge of the reaction part and the folded edge of the hollow part in a relative position in the natural encapsulation state. S4: Cut the composite film folded in step S3 into individual packaging bag blanks using a cutting device, and seal the edges of the packaging bag blanks using a sealing machine.

8. The anti-counterfeiting flexible packaging bag and its preparation method according to claim 7, characterized in that: The reactant contains calcium hydroxide, which is mixed with a small amount of food-grade filler and pressed into a thin sheet to be attached to the inside of the folded edge. The colorant contains phenolphthalein, which is mixed with food-grade ethanol solution, and after adding an aqueous binder, it is coated onto a designated area of ​​the adhesion layer by a gravure coating process. After drying, the ethanol evaporates to form a colorless solid coating.

9. The anti-counterfeiting flexible packaging bag and its preparation method according to claim 7, characterized in that: Optionally, the reactants include potassium iodate and citric acid. Potassium iodate and citric acid are mixed at a mass ratio of 1:3, and a small amount of food-grade carrier is added and applied to the inside of the folded edge through a dry powder coating process. The colorant includes starch. Starch is mixed with a food-grade adhesive to form a slurry, which is then coated onto a designated area of ​​the adhesive layer through gravure coating.

10. The anti-counterfeiting flexible packaging bag and its preparation method according to claim 7, characterized in that: Optionally, the reactant contains sodium bicarbonate, which is mixed with a small amount of food-grade filler and pressed into a sheet to be attached to the inside of the folded edge; the colorant contains anthocyanin, which is mixed with food-grade water-based resin and coated onto a designated area of ​​the adhesive layer by a roller coating process, and after drying, forms a colorless or light-colored solid coating.

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