A hot stamping film and a hot stamping method

Abstract

The application discloses a hot stamping film and a hot stamping method, wherein the hot stamping film comprises a substrate layer, an aluminized layer and a glue layer which are sequentially arranged from outside to inside, the substrate layer is made of transparent degradable high polymer material, and the glue layer is made of hot melt material. The hot stamping film is made of transparent degradable high polymer material, and under the action of high temperature of a hot stamping plate, the substrate layer under the hot stamping plate is in a glassy state, so that the whole hot stamping film falls off and is attached to the surface of a packaging substrate, thereby forming a hot stamping process. At this time, the transparent substrate layer is in the surface layer of the process, so that the initial hot stamping effect is not affected. However, after a period of time, with the contact between the substrate layer and water molecules in the air, the substrate layer is slowly degraded under the hydrolysis of the water molecules. In the degradation process, the substrate layer gradually changes from transparent to opaque, so that the change degree of the transparency can be used to indicate the time process.

Description

Technical Field

[0001] This invention relates to the field of hot stamping technology, and more particularly to a hot stamping film and a hot stamping method. Background Technology

[0002] In existing technologies, patterns obtained by electroplated aluminum hot stamping can only be used for decoration and do not have a timing function, making their functionality too limited. Furthermore, existing timing processes typically require the application of timing labels, which is costly. Summary of the Invention

[0003] Therefore, it is necessary to provide a hot stamping film that can provide a hot stamping process with a timing function after hot stamping, in order to solve the above problems.

[0004] In addition, a hot stamping method is also provided.

[0005] A hot stamping film includes a substrate layer, an aluminum plating layer, and an adhesive layer stacked sequentially from the outside to the inside. The substrate layer is made of a transparent biodegradable polymer material, and the adhesive layer is made of a hot melt material.

[0006] In one embodiment, the biodegradable polymer material is selected from at least one of polylactic acid, polylactic acid-glycolic acid copolymer, polycaprolactone, and polyethylene glycol.

[0007] In one embodiment, a partially perforated barrier layer is further provided on the side of the substrate layer away from the aluminum plating layer.

[0008] In one embodiment, the barrier layer material is UV varnish or water-based paraffin.

[0009] In one embodiment, the thickness of the aluminum plating layer is 0.01µm-0.02µm.

[0010] In one embodiment, the material used to prepare the adhesive layer is selected from at least one of ethylene and its copolymers hot melt adhesives, polyester hot melt adhesives, polyamide hot melt adhesives, and polyurethane hot melt adhesives.

[0011] In one embodiment, the adhesive layer contains a volatile dye or a colored sublimation material.

[0012] In one embodiment, the volatile dye is selected from at least one of guaiac blue hydrocarbons, guaiac blue hydrocarbon derivatives, azo dyes, and anthraquinone dyes.

[0013] In one embodiment, the sublimation material is selected from ferrocene, indigo, or elemental iodine.

[0014] The aforementioned hot stamping film has a substrate layer made of a transparent biodegradable polymer material. During hot stamping, under the high temperature of the hot stamping plate, the substrate layer below the plate is in a vitrified state, causing the hot stamping film to detach and adhere to the surface of the packaging substrate, thus forming the hot stamping process. At this time, the degradation process of the substrate layer is zero, and it is in a transparent state. However, after a period of time, as the substrate layer comes into contact with water molecules in the air, it undergoes slow degradation under the hydrolysis of water molecules. During the degradation process, the substrate layer will gradually change from transparent to opaque. Therefore, the degree of change in its transparency can be used to indicate the progress of time.

[0015] A hot stamping method includes the following steps:

[0016] A hot stamping plate and a hot stamping film are provided, wherein the hot stamping film is any one of the hot stamping films described in 1-9 above, and the hot stamping film includes a substrate layer;

[0017] The hot stamping process is performed on a printing substrate using the hot stamping plate and the hot stamping film, wherein the hot stamping temperature is higher than the melting point of the substrate layer. Attached Figure Description

[0018] Figure 1 A schematic diagram of the hot stamping film structure according to one embodiment;

[0019] Figure 2 A schematic diagram of a hot stamping film structure according to another embodiment;

[0020] Figure 3 This is a flowchart of a hot stamping method according to one embodiment. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is considered to be "connected" or "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "upper," "lower," "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0023] The following section provides a more detailed description of the hot stamping film and hot stamping method, in conjunction with the accompanying drawings and specific embodiments.

[0024] Please see Figure 1 One embodiment of the hot stamping film includes a substrate layer 10, an aluminum plating layer 20, and an adhesive layer 30 stacked together.

[0025] The substrate layer 10 is used to support the aluminum plating layer 20 and the adhesive layer 30. The substrate layer 10 is made of a transparent biodegradable film. On the one hand, because the substrate layer 10 is transparent, after the hot stamping film is hot stamped, the user can see the aluminum plating layer 20 located below the substrate layer 10 through the substrate layer 10. On the other hand, the substrate layer 10 is located on the outermost surface, so that after the hot stamping film is hot stamped, the substrate layer 10 located on the outer surface can fully contact the water molecules in the air, thereby allowing the substrate layer 10 to undergo hydrolysis under the action of water molecules. During the hydrolysis process, its transparency changes slowly. The process of transparency change can be used to indicate the progress of time, thus enabling the hot stamping film to have a timing function.

[0026] Specifically, biodegradable polymers can be polymerized from oligomers, forming ester bonds during the polymerization process. These bonds have a long chain structure at the microscopic level, with atoms on the chain connected by covalent bonds. During crystallization, the chain segments cannot move freely enough. Therefore, this structure hinders their regular stacking and arrangement, resulting in a large number of lattice defects inside the polymer crystal. Based on the number of lattice defects, the biodegradable polymer can be divided into two parts: an amorphous region and a crystalline region.

[0027] Biodegradable polymers can degrade under the action of water molecules. This degradation process is a continuous erosion process: First, water molecules penetrate into the biodegradable polymer, causing the polymer molecular chains to be in a relaxed state; second, the ester bonds in the biodegradable polymer undergo hydrolysis and breakage under the action of water; subsequently, the amorphous and crystalline regions of the molecular chains undergo hydrolysis and breakage successively under the action of water, causing the biodegradable polymer to be degraded from a high polymer to an oligomer. During this process, the color of the substrate layer 10 changes from transparent to opaque white.

[0028] Optionally, the biodegradable polymer material is selected from at least one of polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA), polyglycolic acid (PGA), polycaprolactone, and polyethylene glycol.

[0029] Polyglycolic acid (PGA), also known as polyglycolic acid or polyglycolic acid, is initially a translucent light yellowish-brown color. It is polymerized from glycolic acid. PGA has a melting point of around 225°C and exhibits strong hydrophilicity and a rapid hydrolysis rate. When its molecular weight exceeds 20,000, it can be stretched into films. Tests have shown the following relationship between molecular weight and film degradation time: at a molecular weight of 20,000, the complete degradation time under the influence of water molecules is approximately 100 days; at 40,000, it is approximately 220 days; and at 60,000, it is approximately 400 days. This makes it suitable for preparing hot stamping films with medium to short time cycles. The degradation time of PGA is positively correlated with its molecular weight; therefore, the time cycle of the hot stamping film can be controlled by adjusting the molecular weight of PGA. When polyhydroxyacetic acid polymers are hydrolyzed, the resulting product is an oligomer of glycolic acid. During the hydrolysis process, its color gradually changes from translucent yellowish-brown to opaque white.

[0030] Polylactic acid (PLA) can be polymerized from lactide. Its initial color is transparent and it has high weather resistance. The melting point of PLA is 160℃~190℃. Its film usually takes about 2 years to completely degrade under the action of water molecules. It is suitable for preparing hot stamping films with long time cycles. During the hydrolysis process, its color gradually changes from transparent to opaque white.

[0031] Polylactic acid-glycolic acid copolymer (PLGA) is initially transparent and has a melting point of 262°C. It can be polymerized from lactide and glycolide. The higher the proportion of glycolide, the shorter the degradation time, and vice versa. Therefore, the degradation time of polylactic acid-glycolic acid copolymer (PLGA) can be controlled by adjusting the ratio of lactide to glycolide. During the hydrolysis process, its color gradually changes from transparent to white.

[0032] Furthermore, biodegradable polymers possess terminal carboxyl groups, which can act as autocatalysts during the hydrolysis process. As the polymer degrades, the number of molecular chains increases, and the number of terminal carboxyl groups also increases rapidly. Under the autocatalytic effect of the terminal hydroxyl groups, the degradation rate will further accelerate. Therefore, the overall degradation rate of biodegradable polymers is slow at the beginning and fast at the end. Correspondingly, the color change rate of the timed hot stamping film also exhibits a slow start and fast finish. Therefore, as the timer deadline approaches, the psychological cue that the timer hot stamping film is about to reach the user will be significantly stronger.

[0033] Optionally, the biodegradable polymeric material having a terminal carboxyl group includes polyglycolic acid, polylactic acid, and polylactic acid-glycolic acid copolymer.

[0034] In another implementation, please refer to Figure 2 A partially perforated barrier layer 40 is also provided on the side of the substrate layer 10 away from the aluminum plating layer 20. The barrier layer 40 is transparent and can prevent water molecules from passing through, thereby preventing the substrate layer 10 below the barrier layer 40 from contacting water molecules and thus hydrolyzing.

[0035] Specifically, the barrier layer 40 is partially hollowed out. After the hot stamping film is hot stamped, the substrate layer 10 below the barrier layer 40 can be prevented from being hydrolyzed due to the barrier effect of the barrier layer 40, thus maintaining a transparent state for a long time. The substrate layer 10 below the hollowed-out part undergoes slow hydrolysis due to contact with water molecules. The transparency changes gradually during the hydrolysis process, thus forming specific graphics on the substrate layer 10 in the hollowed-out part. These graphics have both anti-counterfeiting and timing functions.

[0036] Optionally, the barrier layer 40 material includes, but is not limited to: UV varnish, water-based paraffin.

[0037] The aluminum plating layer 20 is formed by uniformly attaching a layer of aluminum atoms to the substrate layer 10 through vacuum evaporation to form an aluminum foil layer. The aluminum plating layer 20 is used to make the hot stamping film appear metallic.

[0038] In this embodiment, the thickness of the aluminum plating layer 20 is 0.01um-0.02um. By limiting the thickness of the aluminum plating layer 20, on the one hand, the aluminum plating layer 20 has a strong opacity while presenting a metallic color, which can prevent the background color below the hot stamping process from showing through after hot stamping; on the other hand, the aluminum plating layer 20 has a certain degree of air permeability. At this time, there are large gaps between aluminum atoms in the aluminum plating layer 20. When volatile dyes or colored sublimation materials are provided in the adhesive layer 30, the molecules of volatile dyes or colored sublimation materials can enter the substrate layer 10 through these gaps.

[0039] In another embodiment, the thickness of the aluminum plating layer 20 is greater than or equal to 0.03 μm. This thickness of aluminum plating layer 20 has extremely high opacity and extremely strong airtightness, so that the electroplated aluminum hot stamping presents a strong metallic color effect to the outside.

[0040] The adhesive layer 30 is made of hot melt adhesive material. During hot stamping, the adhesive layer 30 can melt at the hot stamping temperature, thereby adhering to the surface of the packaging substrate to form the hot stamping process.

[0041] Optionally, the materials used to prepare the adhesive layer 30 include, but are not limited to: ethylene and its copolymers hot melt adhesives, polyester hot melt adhesives, polyamide hot melt adhesives and polyurethane hot melt adhesives.

[0042] In this embodiment, a small amount of volatile dye or colored sublimation material is provided in the adhesive layer 30. The volatile dye or colored sublimation material can exist in the form of gaseous molecules after volatilization or sublimation. Under the action of vapor pressure, the volatile dye molecules or colored sublimation material molecules in the adhesive layer 30 can migrate towards the substrate layer 10 through the gaps between aluminum atoms. When the hot stamping film is applied to the surface of the packaging substrate, initially, because the biodegradable polymer material in the substrate layer 10 mainly exists in the form of high molecular weight polymers, its adsorption capacity for volatile dyes or colored sublimation material molecules is low. Therefore, the substrate layer 10 does not show color. As the biodegradable polymer material in the substrate layer 10 hydrolyzes, the biodegradable polymer material is hydrolyzed from high molecular weight polymers into low molecular weight polymers, creating tiny gaps between the low molecular weight polymers. These gaps can adsorb volatile dye molecules or colored sublimation material molecules. At this time, the substrate layer 10 has a binary color-changing effect: on the one hand, as the substrate layer 10 hydrolyzes, the substrate layer 10 gradually changes from transparent to opaque; on the other hand, as the substrate layer 10 adsorbs volatile dye molecules or colored sublimation material molecules, its color will gradually transition to the color of the volatile dye or colored sublimation material, making the color change of the substrate layer 10 more noticeable, thereby highlighting the timing effect and anti-counterfeiting effect of the hot stamping process.

[0043] Optionally, volatile dyes include, but are not limited to: guaiac blue, guaiac blue derivatives, azo dyes, and anthraquinone dyes.

[0044] Optionally, the sublimation materials include, but are not limited to: ferrocene, indigo and elemental iodine.

[0045] The aforementioned hot stamping film has a substrate layer 10 made of a transparent biodegradable polymer material. During hot stamping, under the high temperature of the hot stamping plate, the substrate layer 10 below the hot stamping plate is in a vitrified state, causing the hot stamping film to peel off as a whole and adhere to the surface of the packaging substrate, forming the hot stamping process. At this time, the degradation process of the substrate layer 10 is zero and it is in a transparent state. However, after a period of time, as the substrate layer 10 comes into contact with water molecules in the air, the substrate layer 10 undergoes slow degradation under the hydrolysis of water molecules. During the degradation process, the substrate layer 10 will gradually change from transparent to opaque. Therefore, the degree of change in its transparency can be used to indicate the time process.

[0046] Furthermore, during the hot stamping process, under the high temperature of the hot stamping plate, the substrate layer 10 undergoes a transformation from solid to glassy to solid. During this transformation, the molecular chains of the biodegradable polymer material are rearranged. Therefore, even if the substrate layer 10 material undergoes partial hydrolysis before hot stamping, the rearrangement of the molecular chains of the biodegradable polymer material can eliminate the opaque effect caused by hydrolysis in the substrate layer 10, achieving a visual "zeroing" from opaque to transparent, thereby making the timing function of the hot stamping film more accurate.

[0047] Please see Figure 3 One embodiment of the hot stamping method includes the following steps:

[0048] Step S10: Provide a hot stamping plate and a hot stamping film, wherein the hot stamping film is any one of the hot stamping films described above, and the hot stamping film includes a substrate layer 10.

[0049] Step S20: Perform hot stamping on the printing substrate using the hot stamping plate and the hot stamping film, wherein the hot stamping temperature is higher than the melting point of the substrate layer 10.

[0050] Specifically, the temperature of the hot stamping plate is higher than the melting point of the substrate layer 10. During the hot stamping process, the substrate layer 10 changes from a solid state to a glassy state under the high temperature and pressure of the hot stamping plate, and is completely detached from the roll of hot stamping film and attached to the packaging substrate to form the hot stamping process.

[0051] The following are specific examples.

[0052] Example 1

[0053] Please see Figure 1 This embodiment provides a hot stamping film, which includes a substrate layer 10, an aluminum plating layer 20 and an adhesive layer 30 stacked sequentially from the outside to the inside.

[0054] In this embodiment, the substrate layer 10 is a polyglycolic acid (PGA) film with a molecular weight of 20,000, the aluminum plating layer 20 has a thickness of 0.03 μm, and the adhesive layer 30 is an olefin and its copolymer hot melt adhesive.

[0055] The aforementioned hot stamping film has a substrate layer 10 made of a transparent biodegradable polymer material. During hot stamping, under the high temperature of the hot stamping plate, the substrate layer 10 below the hot stamping plate is in a vitrified state, causing the hot stamping film to peel off as a whole and adhere to the surface of the packaging substrate, forming the hot stamping process. At this time, the transparent substrate layer 10 is on the outermost layer of the process, so it does not affect the initial hot stamping effect. However, after a period of time, as the substrate layer 10 comes into contact with water molecules in the air, the substrate layer 10 undergoes slow degradation under the hydrolysis of water molecules. The degradation process takes about 100 days. During the degradation process, the substrate layer 10 will gradually change from transparent to opaque. Therefore, the degree of change in its transparency can be used to indicate the time progress.

[0056] Example 2

[0057] The hot stamping film provided in this embodiment is similar to the hot stamping film provided in Example 1, except that: (1) the substrate layer 10 is a polyhydroxyacetic acid (PGA) film with a molecular weight of 40,000; (2) the thickness of the aluminum plating layer 20 is 0.02 μm; (3) the adhesive layer 30 is a polyester hot melt adhesive, and the adhesive layer 30 contains the volatile dye guaiac blue hydrocarbon.

[0058] The hot stamping film described above contains a small amount of volatile dyes or colored sublimation materials in the adhesive layer 30. The volatile dyes or colored sublimation materials can exist in the form of gaseous molecules after volatilization or sublimation. Under the action of vapor pressure, the volatile dye molecules or colored sublimation material molecules in the adhesive layer 30 can migrate towards the substrate layer 10 through the gaps between aluminum atoms. When the hot stamping film is applied to the surface of the packaging substrate, initially, because the biodegradable polymer material in the substrate layer 10 mainly exists in the form of high molecular weight polymers, its adsorption capacity for volatile dyes or colored sublimation material molecules is low. Therefore, the substrate layer 10 does not show color. As the biodegradable polymer material in the substrate layer 10 hydrolyzes, the biodegradable polymer material is hydrolyzed from high molecular weight polymers into low molecular weight polymers, creating tiny gaps between the low molecular weight polymers. These gaps can adsorb volatile dye molecules or colored sublimation material molecules. At this time, the substrate layer 10 has a binary color-changing effect: on the one hand, as the substrate layer 10 hydrolyzes, the substrate layer 10 gradually changes from transparent to opaque, and its degradation process takes about 220 days; on the other hand, as the substrate layer 10 adsorbs volatile dye molecules or colored sublimation material molecules, its color will gradually transition to the color of volatile dyes or colored sublimation materials, making the color change of the substrate layer 10 more noticeable, thereby highlighting the timing effect and anti-counterfeiting effect of the hot stamping process.

[0059] Example 3

[0060] Please see Figure 2 The hot stamping film provided in this embodiment is similar to the hot stamping film provided in Embodiment 2, except that: (1) the substrate layer 10 is a polylactic acid (PLA) film; (2) the thickness of the aluminum plating layer 20 is 0.01 μm; (3) the adhesive layer 30 is a polyurethane hot melt adhesive, and the adhesive layer 30 contains sublimation material iodine; (4) a barrier layer 40 is also provided on the side of the substrate layer 10 away from the aluminum plating layer 20, and the barrier layer 40 is hollowed out. In this embodiment, the barrier layer 40 is water-based paraffin wax.

[0061] In the aforementioned hot stamping film, after the hot stamping film is hot stamped, the substrate layer 10 below the barrier layer 40 can be prevented from being hydrolyzed due to the barrier effect of the barrier layer 40, thus maintaining a transparent state for a long time. However, the substrate layer 10 below the hollowed-out area undergoes slow hydrolysis due to contact with water molecules, and its degradation process takes about 2 years. During the hydrolysis process, the transparency gradually changes, thus forming a graphic on the substrate layer 10 in the hollowed-out area. This graphic also has anti-counterfeiting and timing functions.

[0062] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A hot stamping film, characterized in that, The material comprises a substrate layer, an aluminum plating layer, and an adhesive layer, which are stacked sequentially from the outside to the inside. The substrate layer is made of a transparent and biodegradable polymer material, the adhesive layer is made of a hot-melt material, the aluminum plating layer has a thickness of 0.01µm-0.02µm, and the adhesive layer contains a sublimation material, which is elemental iodine.

2. The hot stamping film according to claim 1, characterized in that, The biodegradable polymer material is selected from at least one of the following: polylactic acid, polylactic acid-glycolic acid copolymer, polycaprolactone, and polyethylene glycol.

3. The hot stamping film according to claim 2, characterized in that, The substrate layer also has a partially perforated barrier layer on the side away from the aluminum plating layer.

4. The hot stamping film according to claim 3, characterized in that, The barrier layer material is UV varnish or water-based paraffin.

5. The hot stamping film according to claim 1, characterized in that, The material used to prepare the adhesive layer is selected from at least one of ethylene and its copolymers hot melt adhesives, polyester hot melt adhesives, polyamide hot melt adhesives, and polyurethane hot melt adhesives.

6. A hot stamping method, characterized in that, Includes the following steps: A hot stamping plate and a hot stamping film are provided, wherein the hot stamping film is the hot stamping film according to any one of claims 1-5, and the hot stamping film includes a substrate layer; The hot stamping process is performed on a printing substrate using the hot stamping plate and the hot stamping film, wherein the hot stamping temperature is higher than the melting point of the substrate layer.

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