Vehicle license plate laminate

Abstract

The present application relates to a kind of laminates for vehicle number plate, the laminates include in turn: protective layer, reflective material layer and metal substrate layer, wherein, the protective layer includes transparent resin layer and adhesive layer, the thickness of the transparent resin layer is 0.5 ~ 20 μm, the thickness of the adhesive layer is 0.5 ~ 20 μm, the adhesive layer includes hot melt adhesive, the melting point of the hot melt adhesive is 110 DEG C ~ 250 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of motor vehicle license plate manufacturing. Specifically, it relates to a motor vehicle license plate with a transparent hot stamping layer, wherein the hot stamping layer is transparent and serves as a protective layer for the license plate. Background Technology

[0002] Motor vehicle license plates have been mandated for use as identification for motor vehicles. They typically use characters (patterns, symbols, words / letters or numbers) to register or verify identity or other (legal) information.

[0003] Various types of vehicle license plates exist globally, and a protective layer is widely used to protect the inner layer containing the characters. For example:

[0004] Some vehicle license plates are made by coating metal with paint; both the background color and the number characters are painted, resulting in a license plate with no retroreflective properties. Other license plates are made by pasting various non-reflective films onto metal, with printed graphics on the films, and then applying a protective film or roller coating of varnish ink as a protective layer.

[0005] In addition, some vehicle license plates consist of a reflective material glued onto a metal surface (for example, a typical reflective material structure diagram is given in reference 1). The reflective material can be further printed with colored patterns, while the characters used for identification are opaque and colored via hot stamping. In other cases, the vehicle license plate consists of a reflective material glued onto a metal surface, with colored patterns printed on the outside of the reflective material, and then a protective film or a varnish ink is applied as a protective layer.

[0006] Currently, some countries in Africa and the Americas use more complex patterns, and some use inkjet printing on the outside of reflective materials. However, because inkjet printing inks do not have a protective film, their weather resistance is poor, and they fade severely within two or three years. To improve weather resistance, sometimes a protective film is applied after inkjet printing or a layer of varnish ink is rolled on to increase weather resistance.

[0007] In addition, in the above-mentioned method of applying a protective film as a protective layer, the protective film usually has a certain thickness and is a pressure-sensitive adhesive layer. By heating and applying pressure, the surface film is bonded to the inner layer, thereby playing a protective role.

[0008] In other aspects, it is known that there are many ways to make license plates. One common method is stamping. After stamping, the reflective material must not crack or have other defects. Then, the characters and borders can be colored by hot stamping or roller coating, or conversely, only the background can be colored while the characters and borders are not colored.

[0009] Another method is the peel-off method, where the reflective material characters and background color are separated after stamping. Then, the reflective material on the characters and borders is peeled off from the substrate. The substrate used in this method is usually colored, such as black, blue, or red. Alternatively, some countries use number plates where the design is first printed, but the characters and borders are not rolled or hot-stamped; instead, the reflective film is peeled off from the substrate.

[0010] During the stamping process for producing license plates, the mechanical impact during stamping may cause the protective film and adhesive on the reflective material to detach, or the protective film to crack. Even the reflective material itself may crack due to differences in tension. This will inevitably affect the performance or lifespan of the vehicle license plate.

[0011] In the peeling process, on the one hand, the adhesive layer connecting the reflective material to the metal substrate must not be too viscous; otherwise, the adhesive will stick to the substrate during peeling. On the other hand, due to the different tensions between the reflective material and the protective film on it, and because the protective film is relatively thick and not easily broken during stamping, it is also possible for the reflective film to detach entirely from the substrate during peeling.

[0012] The above methods are all designed to address the need for protective films on vehicle license plates with printed patterns on the reflective material.

[0013] Furthermore, when using varnish ink as a protective layer, it is usually applied by roller coating. Varnish ink has the following drawbacks: First, it has a strong odor and produces a high amount of volatile organic compounds (VOCs), significantly impacting the environment. Second, varnish ink cannot be roller-coated before character stamping because its stretchability can cause cracking or peeling during stamping. Third, roller coating or spraying after stamping can lead to ink buildup due to uneven surfaces, resulting in inconsistent surface thickness and affecting the retroreflective coefficient of the reflective material, thus reducing its performance. Finally, drying the ink requires significant energy and space, especially for large batches of vehicle license plates.

[0014] References:

[0015] Reference 1: CN101571607A Summary of the Invention

[0016] The problem the invention aims to solve

[0017] As mentioned above, when using an ink layer as a protective layer, there are various limitations due to factors such as environmental protection, preparation process, energy consumption, and site occupation.

[0018] Additionally, when patterns need to be sprayed onto the surface of the reflective material, the process typically involves printing or spraying the pattern onto one surface of the reflective material before attaching the other side of the reflective material to the metal plate of the license plate. Next, a protective film with a pressure-sensitive adhesive layer is laminated onto the patterned surface to form a protective layer. Then, the entire license plate is stamped to highlight numbers and other symbols. Through continuous practice, the following problems have been identified in this process:

[0019] In some cases, when the protective layer is applied to the reflective material surface, it needs to be cut as needed. Alternatively, after the license plate stamping process, in areas where the reflective material is not needed (such as protruding parts), the reflective material along with the protective layer needs to be cut and peeled off during stamping. Therefore, this requires the protective layer itself to have good cutability. During the stamping operation after the protective layer is applied, the protective layer and the reflective layer are stamped simultaneously. To ensure that the protective layer does not crack in the unstamped areas, it needs to have a certain degree of toughness. However, currently, when pressure-sensitive adhesives are used as the adhesive layer for the protective layer, there are certain problems in achieving both.

[0020] In addition, due to the need to meet the above two cutting requirements, the adhesive layer in the protective layer that contacts the reflective material usually uses pressure-sensitive adhesive. Although such adhesive is beneficial to meet the cutting requirements, it is actually prone to cracking of the protective layer and the reflective material surface during stamping because it has a certain degree of re-peelability.

[0021] Therefore, in view of the above-mentioned shortcomings of the prior art, the primary objective of this invention is to provide a laminate for use in vehicle (such as motor vehicles or non-motor vehicles) license plates, comprising a protective layer, a reflective layer, and a metal substrate layer, wherein the protective layer includes a transparent resin layer and an adhesive layer. Furthermore, the adhesive layer mainly comprises a hot-melt adhesive, and by optimizing the thickness and other characteristics of the adhesive layer and the transparent resin layer, the laminate exhibits good processability in license plate manufacturing. That is, the protective layer in the stamped area during cutting and stamping is easily cut off, and the stamping process does not cause undesirable cracking of the protective layer itself or between the protective layer and the reflective layer.

[0022] Solution for solving the problem

[0023] The above-mentioned technical problems can be solved by implementing the following technical solutions:

[0024] [1]. The present invention first provides a laminate for vehicle license plates, wherein the laminate comprises, in sequence:

[0025] Protective layer, reflective layer and metal substrate layer,

[0026] in,

[0027] The protective layer comprises a transparent resin layer and an adhesive layer, wherein the thickness of the transparent resin layer is 0.5–20 μm, and the thickness of the adhesive layer is 0.5–20 μm.

[0028] The adhesive layer includes a hot-melt adhesive with a melting point of 110°C to 250°C.

[0029] [2]. According to the laminate described in [1], the protective layer is a hot stamping layer; and a pattern layer is also provided on the surface of the reflective material layer adjacent to the protective layer.

[0030] [3]. The laminate according to [1] or [2], wherein the light transmittance of the transparent resin layer is 70% or more.

[0031] [4]. The laminate according to any one of [1] to [3], wherein the material of the transparent resin layer includes one or more of polyester resin, polycarbonate resin, polyolefin resin, polyacrylate resin or modified thereof.

[0032] [5]. The laminate according to any one of [1] to [4], wherein the hot melt adhesive includes one or more of PA hot melt adhesive, TPU hot melt adhesive, EVA hot melt adhesive or PES hot melt adhesive.

[0033] [6]. The laminate according to any one of [1] to [5], wherein the reflective material layer comprises a patternable surface layer, a support layer, a lens array layer, a focusing layer, a reflective layer and an adhesive layer.

[0034] [7]. The laminate according to any one of [1] to [6], wherein the material of the metal substrate layer is selected from any one of aluminum, aluminum alloy, iron or iron alloy.

[0035] [8]. Furthermore, the present invention also provides a vehicle license plate, wherein the vehicle license plate is obtained by processing the laminate according to any one of [1] to [7] above.

[0036] [9]. According to the vehicle license plate described in [8], wherein the processing includes stamping.

[0037]

[10] . According to the vehicle license plate described in [8] or [9], wherein the vehicle is a motor vehicle.

[0038] The effects of the invention

[0039] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0040] (1) By using hot melt adhesive with specific properties (instead of pressure-sensitive adhesive, which is currently commonly used) as the adhesive layer in the protective layer, the cutability of the adhesive layer of the cut and stamped parts can be ensured when cutting the protective layer and stamping the laminate, while also ensuring that the protective layer / reflective material layer in other parts does not crack.

[0041] (2) By optimizing the thickness of the transparent resin layer and the adhesive layer in the protective layer, the toughness of the entire protective layer can be taken into account while ensuring cutability.

[0042] (3) The method of the present invention can avoid the use of varnish ink as a protective layer, thus avoiding the volatilization of harmful gases and reducing energy and space consumption. Attached Figure Description

[0043] Figure 1 : A structural diagram of a laminated body in a specific embodiment of the present invention

[0044] A: Protective layer; B: Reflective material layer; C: Metal substrate layer

[0045] 1: Transparent resin layer; 2: Adhesive layer (hot melt adhesive); 3: Surface layer; 4: Support layer;

[0046] 5: Lens array layer; 6: Focusing layer; 7: Reflective layer; 8: Adhesive layer.

[0047] Figure 2 : A structural diagram of the reflective material layer in a laminated body according to a specific embodiment of the present invention

[0048] 2-1: Surface layer; 2-2: Air chamber; 2-3: Lens array layer (glass microspheres);

[0049] 2-4: Reflective layer; 2-5: Support layer; 2-6: Adhesive layer

[0050] Figure 3 : A structural diagram of the reflective material layer in a laminated body according to a specific embodiment of the present invention

[0051] 3-1: Surface layer; 3-2: Lens array layer (prism); 3-3: Reflective layer;

[0052] 3-4: Adhesive layer

[0053] Figure 4 : A structural diagram of the reflective material layer in a laminated body according to a specific embodiment of the present invention

[0054] 4-1: Surface layer; 4-2: Lens array layer (prism); 4-3: Air chamber;

[0055] 4-4: Support layer; 4-5: Adhesive layer

[0056] Figure 5 In one specific embodiment of the present invention, the structure after stamping of the laminated body

[0057] A: Protective layer; B: Reflective material layer; C: Metal substrate layer Detailed Implementation

[0058] The present invention will now be described in detail. The descriptions of the technical features described below are based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0059] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0060] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0061] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0062] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0063] In this specification, the terms "substantially" and "essentially" are used to indicate that the standard deviation from the theoretical model, theoretical data, or target data is within a range of 5%, preferably 3%, and more preferably 1%.

[0064] In this specification, the terms “comprising” and / or “including” are used to indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0065] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements can be combined in any suitable manner in various embodiments.

[0066] The present invention primarily provides a laminate for vehicle license plates, which can be processed by subsequent methods such as stamping to obtain the final license plate.

[0067] The laminated body comprises, in sequence, a protective layer, a reflective layer, and a metal substrate layer. The use of "in sequence" here refers only to the order in which the layers are stacked and does not limit the laminated body to only these three layers.

[0068] (vehicle)

[0069] The vehicle described in this invention can be a motor vehicle, a non-motor vehicle, or other vehicles with various specific functions.

[0070] Preferably, the vehicle of the present invention refers to a motor vehicle, including motor vehicles powered by petrochemical energy and new energy vehicles (hydrogen energy, lithium battery, hybrid power).

[0071] (protective layer)

[0072] The protective layer of this invention mainly serves to protect the laminate, especially the pattern on the surface of the reflective material layer on the laminate, so as to increase the durability of the final vehicle license plate.

[0073] Such a protective layer mainly includes a transparent resin layer located on the outermost layer of the laminate and an adhesive layer for bonding the transparent resin layer and the reflective material layer.

[0074] transparent resin layer

[0075] There are no particular limitations on the transparent resin layer that can be used in this invention, as long as it provides sufficient light transmittance. In some specific embodiments, the transparent resin layer may be made of transparent resin and optional additives.

[0076] In some specific embodiments of the present invention, the transparent resin may be selected from one or more of polyester resins, polycarbonate resins, polyolefin resins, polyacrylate resins, or their modifiers.

[0077] For polyester resins, they can be condensates of aliphatic, aromatic or alicyclic diols and diacids, preferably selected from PET, PBT, etc.

[0078] For polyolefin resins, they can be homopolymers of olefins, copolymers of multiple olefins, or copolymers of olefins with other polymerizable monomers, such as ethylene-vinyl acetate copolymers.

[0079] For acrylate resins, they can be polymers of one or more (meth)acrylates.

[0080] The modifications described above may include modifications to the main chain or side chain of the resin. In some preferred embodiments, the modifications include the introduction of halogen atoms, organosilicon structures, etc.

[0081] Furthermore, there are no particular restrictions in principle on the additives that can be used to form the transparent resin layer. In some specific embodiments, these additives may include one or more mixed additives such as UV protectants, antioxidants, and curing agents. In addition, in some cases, a protective release layer may be used on the surface of the transparent resin layer at the time of manufacture. To ensure a certain degree of release, additives such as silicone oil, talc, and wax may also be used.

[0082] The thickness of the transparent resin layer in this invention can be controlled within the range of 0.5 μm to 20 μm, preferably 0.8 μm to 10 μm, and most preferably 1 μm to 5 μm. If the transparent resin layer is too thin, it cannot provide good mechanical properties and weather protection; for example, cracking of the transparent resin layer may occur during the subsequent stamping process for producing license plates. If the transparent resin layer is too thick, it may result in poor cutability.

[0083] The light transmittance of the transparent resin layer of the present invention mainly refers to the total light transmittance in the visible light band. In some preferred embodiments, with the above-mentioned thickness, the light transmittance of the transparent resin layer can be 70% or more, more preferably 80% or more, and even more preferably 85% or more.

[0084] Adhesive layer

[0085] The adhesive layer of the present invention is used to bond the aforementioned transparent resin layer and reflective material layer (the surface layer). The adhesive layer of the present invention primarily comprises a hot-melt adhesive.

[0086] In some specific embodiments, the content of hot melt adhesive in the adhesive layer is 80% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more.

[0087] In the most preferred embodiment, the adhesive layer of the present invention is substantially entirely formed of a hot melt adhesive.

[0088] For the hot-melt adhesive of the present invention, its melting point is 110°C to 250°C, preferably 130°C to 220°C, and more preferably 140°C to 210°C. A melting point that is too low will result in poor cutability of the adhesive layer and may also cause cracking of the transparent resin layer itself during stamping, as well as cracking between the transparent resin layer and the reflective layer. A melting point that is too high will lead to difficulties in processing or use, or uneven adhesion.

[0089] The "melting point" of this invention is the temperature at which the viscosity of the hot melt adhesive reaches its lowest point when heated from low to high.

[0090] Furthermore, the thickness of the adhesive layer of the present invention can be 0.5 μm to 20 μm, preferably 0.8 μm to 10 μm, and most preferably 1 μm to 5 μm. If the thickness is too low, it will result in poor mechanical strength and adhesion; if the thickness is too high, it may lead to uneven adhesion and poor cutability during bonding.

[0091] Compared with the pressure-sensitive adhesives commonly used in the prior art, the hot melt adhesive used in this invention has better adhesion, while also balancing toughness and cutability, and has better processability.

[0092] (Reflective material layer)

[0093] There are no particular limitations on the reflective material layers that can be used in this invention, and commercially available varieties commonly used in the art can be used.

[0094] These reflective layers can be commercially available encapsulated glass microsphere reflective films, glass microsphere capsule reflective films, and prism reflective films, such as NIKKALITE brand reflective materials of SCL, ELG, FMG, UL, CRG, and ECE grades from Enshiai (Hangzhou) Film Co., Ltd. In other words, the reflective material surface can be PVC or PU, acrylic resin, PMMA, or PC-based reflective materials, and the retroreflective structure can be microsphere-type or prism-type.

[0095] In some preferred embodiments, the reflective material layer includes a patternable surface layer, a support layer, a transparent array layer, a focusing layer, a reflective layer, and an adhesive layer (such as...). Figure 1 (As shown).

[0096] surface layer

[0097] The aforementioned surface layer is typically a transparent layer, and this surface layer allows for the formation of various patterns through printing, etc., or such patterns can be embedded in such a transparent layer.

[0098] For such a surface layer, in some specific embodiments, the material may be selected from at least one of acrylic resin, alkyd resin, fluororesin, vinyl chloride resin, polyester, polyurethane resin, polyethylene terephthalate, and polycarbonate. Considering weather resistance and processability, at least one of acrylic resin, polyester, and vinyl chloride resin is preferred, while considering suitability for coloring or dispersibility of colorant during coloring, acrylic resin is preferred.

[0099] In some other specific embodiments, colored pigments or dyes may be added to the resin in the surface layer, preferably transparent pigments. Pigments or dyes can be the following:

[0100] Yellow: Colorants such as isoindoline, isoindoline, quinoline, anthraquinone, pyrazolone, flavanone, benzimidazolone, and nickel azo dyes.

[0101] Red: Coloring agents of anthraquinone, dinaphthalene, quinacrine, indigo, etc.

[0102] Blue: Phthalocyanine series, styracil reduction series, anthraquinone series, cobalt series, etc.

[0103] Green: Colorants such as phthalocyanine, emerald green, chromium oxide, and cadmium.

[0104] Brown: Iron oxide series coloring agent, or a combination of isoindole ketone series yellow coloring agent, naphthalene-benzene series red coloring agent and phthalocyanine series blue coloring agent;

[0105] Orange: Single color can be anthraquinone, pyrazolone, violet ketone, naphthalene-benzene, quinacrine, or a combination of isoindoleone yellow colorant and naphthalene-benzene red colorant;

[0106] White: Colorants based on phthaloyl, zinc, lead, etc.

[0107] Black: Colorants for carbon black, aniline black, dinaphthalene-impregnated benzene black, titanium black, etc.

[0108] Furthermore, in some specific embodiments, the thickness of the surface layer can be 10μm to 150μm, preferably 20μm to 60μm, and most preferably 30μm to 50μm.

[0109] support layer

[0110] Similar to the surface layer described above, the support layer can also be a transparent layer, and its material can be selected from at least one of acrylic resin, alkyd resin, fluororesin, vinyl chloride resin, polyester resin, polyurethane resin, and polycarbonate. Considering weather resistance and processability, at least one of acrylic resin, polyester, and vinyl chloride resin is preferred, while considering suitability for coloring or dispersibility of coloring agents, acrylic resin is preferred.

[0111] Similarly, it can have the same colored pigments or dyes as the surface layer.

[0112] Lens array layer

[0113] The lens array layer of the present invention can be a lens array layer formed of light-transmitting microspheres or prisms. In some specific embodiments, the lens array layer is at least partially embedded in the adjacent upper and lower layers, for example, the lens array layer is simultaneously partially embedded in the support layer and the focusing layer described below.

[0114] Furthermore, for the lens array layer of the present invention, the lens array is preferably a structural layer with retroreflective properties.

[0115] In some specific embodiments, the lens elements in the lens array are of any shape with refractive properties, such as light-transmitting microspheres or prisms. In some specific embodiments, the light-transmitting microspheres can be spherical, rod-shaped, ellipsoidal, or any combination thereof; in other specific embodiments, the prism is a serrated (triangular) prism.

[0116] The material of the microspheres or prisms is composed of at least one of glass, ceramic, polymer, and mineral. In some preferred embodiments, their refractive index can be 1.7 to 2.5, and most preferably 2.19 to 2.21. The (long) diameter of the microspheres is 10 μm to 150 μm, preferably 50 μm to 110 μm, and most preferably 60 μm to 110 μm.

[0117] Focusing layer

[0118] The focusing layer of this invention is a transparent focusing layer. There are no particular limitations on its material and structure; it is mainly used to focus reflected light, thereby visually improving the clarity of the reflective surface.

[0119] The material of the transparent focusing layer may include a transparent resin, which may be selected from at least one of acrylic resin, alkyd resin, fluororesin, vinyl chloride resin, polyester resin, polyurethane resin, and polycarbonate. Considering weather resistance and processability, at least one of acrylic resin, polyester, and vinyl chloride resin is preferred, and acrylic resin is more preferred.

[0120] In addition, from the perspective of imparting focusing properties, the boundary between the transparent focusing layer and the opaque layer described below has a continuously undulating curved surface structure. Such a curved surface provides a focusing effect through the structure concave towards the opaque layer.

[0121] reflective layer

[0122] For the reflective layer of the present invention, a metallic reflective film commonly used in the art can be used.

[0123] In some specific implementations, it can be a metal film, such as a film of aluminum (Al), silver (Ag), or gold (Au).

[0124] In other specific implementations, it can be a coating, namely, a highly reflective metal such as aluminum (Al), silver (Ag), or gold (Au) coated on the surface of a metal or resin film.

[0125] adhesive layer

[0126] The material of the adhesive layer in this invention is not particularly limited; commonly used pressure-sensitive adhesives in the art, such as (meth)acrylic pressure-sensitive adhesives, can be used. Alternatively, the adhesive layer can also be a layer formed by hot melt adhesive. However, from the perspective of re-peelability, pressure-sensitive adhesives are preferred.

[0127] When using pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive can be 10μm to 150μm, preferably 20μm to 60μm, and most preferably 30μm to 50μm.

[0128] The hot melt adhesive can be PA hot melt adhesive, TPU hot melt adhesive, EVA hot melt adhesive, or PES hot melt adhesive. The thickness of the hot melt adhesive can be 1μm to 150μm, preferably 3μm to 40μm, and most preferably 6μm to 30μm.

[0129] In other specific embodiments, other existing structures can also be used for the reflective material layer of the present invention, for example... Figures 2-4 The structure shown.

[0130] in Figure 2 and Figure 4 In this process, the lens array layer is (partially) placed in an air chamber. Figure 3 and Figure 4 The lens array layer is set up as a prism layer.

[0131] (Metal substrate layer)

[0132] There are no particular limitations on the metal substrate layer of the present invention, and various stampable metal substrates can be selected as needed or in accordance with local regulations.

[0133] In some specific implementations, the material of the metal substrate layer can be selected from any of aluminum, aluminum alloys, iron, iron alloys, etc.

[0134] (Preparation of vehicle license plates)

[0135] The vehicle license plate of the present invention is obtained by processing the above-described laminated body. In some preferred embodiments, the processing includes:

[0136] First, the pattern is printed onto the reflective material using a roll-to-roll inkjet printer. Then, the roll of reflective material is attached to an aluminum plate. The aluminum plate is then cut into the shape of the license plate. The license plate is then sent to a hot stamping machine to have a protective layer hot stamped on it. After the protective layer is hot stamped, the license plate is sent to a license plate stamping machine to stamp the characters. The reflective material and protective layer on the surface of the characters are then removed. Finally, the color of the number plate characters is rolled or hot stamped.

[0137] The process of the hot stamping protective layer of the present invention can be specifically listed as follows:

[0138] The hot stamping machine's processing speed is 1–10 m / min, with 2–5 m / min being optimal. Assuming the vehicle license plate thickness is greater than 1.1 mm, the distance between the rubber heating roller and the metal roller on the hot stamping machine should ideally be 0.7 mm–1 mm. The hot stamping temperature is 130℃–250℃, with 180℃–200℃ being optimal. These temperatures are not the machine's set temperatures, but rather the surface temperature of the rubber roller before hot stamping, and the temperature remains stable during the hot stamping process.

[0139] According to the above process, the protective layer exhibits excellent cutability during hot stamping. After hot stamping, the vehicle license plate with the hot stamping does not crack or peel off during the stamping process.

[0140] Example

[0141] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0142] Example 1

[0143] Using a MIMAKI JV33 roll-to-roll inkjet printer, the required printed pattern is printed onto the L851200LK reflective material from Enshiai (Hangzhou) Film Co., Ltd. The reflective material is then bonded to the aluminum plate for the license plate. A punch press equipped with a semi-finished license plate mold (license plate shape and mounting holes) then stamps out the semi-finished product. Next, a transparent protective layer (hot melt adhesive melting point 150℃, thickness 12μm; transparent resin layer 15μm) is hot-stamped on a hot-stamping machine at a speed of 3m / min and a roller temperature of 190℃. The hot-stamped license plate is then stamped again on a license plate character stamping machine. The stamped license plate characters are then coated or hot-stamped.

[0144] Example 2

[0145] The L851200LK reflective material from Enshiai (Hangzhou) Film Co., Ltd. is bonded to the aluminum plate for the license plate. Then, a punch press equipped with a semi-finished license plate mold (license plate shape and mounting holes) stamps out the semi-finished product. The desired pattern is then printed on a MIKAKI UJV-160 flatbed inkjet printer. Finally, a transparent protective layer (hot melt adhesive melting point 150℃, thickness 12μm; transparent resin layer 15μm) is hot-stamped on a hot-stamping machine at a speed of 3m / min and a roller temperature of 190℃. The hot-stamped license plate is then stamped again on a license plate character stamping machine. The stamped license plate characters are then coated or hot-stamped.

[0146] Comparative Example 1 :

[0147] Same as Example 1, except that the melting point of the hot melt adhesive is 100°C;

[0148] Comparative Example 2

[0149] Same as Example 1, except that the hot melt adhesive thickness is 25 μm;

[0150] Comparative Example 3

[0151] Same as in Example 1, except that the thickness of the transparent resin layer is 0.2 μm;

[0152] Comparative Example 4

[0153] Same as Example 1, except that the thickness of the transparent resin layer is 28 μm.

[0154] Result comparison:

[0155]

[0156] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0157] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A vehicle license plate, wherein the vehicle license plate is obtained by processing a laminated body, the processing including stamping, characterized in that, The laminate comprises, in sequence, a protective layer, a reflective material layer, and a metal substrate layer. in, The protective layer comprises a transparent resin layer and an adhesive layer directly adjacent to the transparent resin layer. The thickness of the transparent resin layer is 0.5–20 μm, and the thickness of the adhesive layer is 0.5–20 μm. The adhesive layer includes a hot melt adhesive with a melting point of 110°C to 250°C, and the content of the hot melt adhesive in the adhesive layer is more than 80% by mass. The hot melt adhesive includes one or more of PA hot melt adhesive, TPU hot melt adhesive, EVA hot melt adhesive or PES hot melt adhesive.

2. The number plate according to claim 1, characterized in that, The protective layer is a hot stamping layer; a pattern layer is also present on the surface of the reflective material layer adjacent to the protective layer.

3. The number plate according to claim 1 or 2, characterized in that, The light transmittance of the transparent resin layer is over 70%.

4. The number plate according to claim 1 or 2, characterized in that, The material of the transparent resin layer includes one or more of polyester resins, polycarbonate resins, polyolefin resins, polyacrylate resins, or their modifiers.

5. The number plate according to claim 1 or 2, characterized in that, The reflective material layer includes a patternable surface layer, a support layer, a lens array layer, a focusing layer, a reflective layer, and an adhesive layer.

6. The number plate according to claim 1 or 2, characterized in that, The material of the metal substrate layer is selected from any one of aluminum, aluminum alloy, iron, or iron alloy.

7. The number plate according to claim 1 or 2, characterized in that, The vehicle in question is a motor vehicle.

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