Laminate for vehicle number plate

Abstract

The present invention relates to a laminate for a vehicle number plate. The laminate sequentially comprises: a protective layer, a reflective material layer and a metal substrate layer, wherein the protective layer includes a transparent resin layer and an adhesive layer, the thickness of the transparent resin layer being 0.5-20 μm, and the thickness of the adhesive layer being 0.5-20 μm. The adhesive layer includes a hot melt adhesive, and the melting point of the hot melt adhesive is 110-250°C.

Description

Laminated body for vehicle number plates Technical Field

[0001] The invention belongs to the field of motor vehicle number plate preparation, and in particular relates to a motor vehicle number 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 Art

[0002] Motor vehicle license plates have been compulsorily used for identification of motor vehicles, and are usually marked with characters (patterns, symbols, words / letters or numbers) to register or verify identity or other (legal) information.

[0003] There are various motor vehicle number plates in the world, and a protective layer is widely used to protect the inner layer with characters, such as:

[0004] Some motor vehicle number plates are made by coating the metal with paint. The background color and the number plate characters are all painted, and the plate as a whole has no retro-reflective properties. Other motor vehicle number plates are made by gluing various non-retro-reflective films onto the metal. The films may have various printed images and texts, and then a protective film or roller-coated varnish ink layer is applied as a protective layer.

[0005] Alternatively, some motor vehicle number plates are made of reflective material bonded to metal (for example, Reference 1 provides a typical reflective material structure diagram). The interior of the reflective material may be further printed with a color pattern, and the characters used for identification are opaque and applied by hot stamping. In other cases, motor vehicle number plates are made of reflective material bonded to metal, with a color pattern printed on the exterior, and then a protective film or roller-coated varnish ink is applied as a protective layer.

[0006] Currently, some countries in Africa and America use more complex designs, and some use inkjet printing on the outside of reflective materials. However, because inkjet printing inks lack a protective film, they have poor weather resistance and fade severely within two to three years. To improve weather resistance, a protective film is sometimes applied after printing, or a layer of varnish ink is roller-coated 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. The surface film and the inner layer are bonded by heating and pressurizing, thereby playing a protective role.

[0008] In other aspects, there are many ways to make license plates. A common one is stamping (Embossed), and after stamping, the reflective material cannot have defects such as cracking. Then, the characters and borders can be colored by hot stamping or roller coating, or conversely, only the background is colored, while the characters and borders are not colored.

[0009] Another method is peel-off. After stamping, the reflective material on the characters and border is separated from the background color. The reflective material on the characters and border is then peeled off from the base plate. Typically, the base plate used in this method is colored, such as black, blue, or red. Alternatively, some countries use number plates where the design is spray-painted first. The characters and border are not roller-coated or hot-stamped, but the reflective film is peeled off the base plate.

[0010] During the stamping process of license plates, the mechanical impact of stamping can cause the protective film on the reflective material to separate from the glue of the reflective material, or the protective film to crack. Even the reflective material can crack due to the difference in tension between the protective film and the reflective material. This will inevitably affect the performance and service life of the motor vehicle number plate.

[0011] In the peeling method, the adhesive layer connecting the reflective material to the metal substrate must not be too sticky, otherwise the glue will stick to the substrate during peeling. Furthermore, due to the different tensions between the reflective material and the protective film, and the thick protective film being less susceptible to being cut during punching, the reflective sheeting may become detached from the substrate during peeling.

[0012] The above methods are all designed to meet the need for protective films for motor vehicle number plates with spray-painted patterns on the outside of the reflective material.

[0013] In addition, when using varnish ink as a protective layer, it is usually carried out by roller coating. Varnish ink has the following defects: first, the ink has a strong odor and produces a lot of volatile organic compounds (VOCs), which has a great impact on the environment. Moreover, varnish ink cannot be roller-coated before the characters are stamped, because the stretchability of the ink will cause cracking or falling off during stamping. When roller-coating or spraying after stamping, the uneven surface will easily cause ink accumulation, and the uneven surface thickness will affect the retroreflection coefficient of the reflective material, that is, it will reduce the performance of the retroreflection coefficient. In addition, since the ink needs to be dried, the drying of large batches of motor vehicle number plates requires energy and space.

[0014] References:

[0015] Reference 1: CN101571607A

[0016] Summary of the Invention

[0017] Problems to be solved by the invention

[0018] As mentioned above, when the ink layer is used as the protective layer, there are limitations due to various factors such as environmental protection, preparation process, energy consumption and site occupation.

[0019] Furthermore, when a pattern is required on the reflective material, the pattern is typically printed or sprayed on one surface before the other side is attached to the metal plate of the license plate. A protective film with a pressure-sensitive adhesive layer is then applied to the patterned surface to form a protective layer. The entire license plate is then stamped to highlight symbols such as numbers. Through continuous practice, the following issues have been identified during this process:

[0020] In some cases, when the protective layer is attached to the surface of the reflective material, it must be cut and severed as needed. Alternatively, after the license plate stamping process, the reflective material and the protective layer must be cut and peeled off together during stamping at the part where the reflective material is not needed (such as the protruding part). Therefore, this requires the protective layer itself to have good cutting properties. During the stamping operation after the protective layer is attached, the protective layer and the reflective layer are stamped at the same time. In order to ensure that the protective layer does not crack in the part that is not stamped, the protective layer is required to have a certain toughness. However, when the protective layer currently uses a pressure-sensitive adhesive as the adhesive layer, there are certain problems in taking both into account.

[0021] In addition, due to the need to meet the above-mentioned two-time cutting requirements, the adhesive layer in the protective layer that contacts the reflective material in the past usually uses a pressure-sensitive adhesive. Although such an adhesive is conducive to meeting the cutting requirements, in fact, due to its certain re-peelability, it is also easy to cause cracks between the protective layer and the reflective material surface during punching.

[0022] Therefore, in view of the above-mentioned deficiencies in the prior art, the primary purpose of the present invention is to provide a laminate that can be used for vehicle (e.g., motor vehicle or non-motor vehicle) number plates, comprising a protective layer, a reflective material layer, and a metal substrate layer, wherein the protective layer comprises a transparent resin layer and an adhesive layer. Furthermore, the adhesive layer primarily comprises a hot-melt adhesive, and by optimizing the thickness and other properties of the adhesive layer and the transparent resin layer, the laminate exhibits good workability in the manufacture of number plates. Specifically, the protective layer can be easily severed in the areas being punched during cutting and stamping, and the punching process does not cause undesirable cracking in the protective layer itself or between the protective layer and the reflective material layer.

[0023] Solutions for solving problems

[0024] The above technical problems can be solved by implementing the following technical solutions:

[0025] [1] The present invention first provides a laminate for a vehicle number plate, wherein the laminate comprises:

[0026] Protective layer, reflective material layer and metal substrate layer,

[0027] in,

[0028] The protective layer includes a transparent resin layer and an adhesive layer. The thickness of the transparent resin layer is 0.5 to 20 μm, and the thickness of the adhesive layer is 0.5 to 20 μm.

[0029] The adhesive layer includes a hot melt adhesive having a melting point of 110° C. to 250° C.

[0030] [2] The laminate according to [1], wherein the protective layer is a hot stamping layer; and a pattern layer is further provided on the surface of the reflective material layer adjacent to the protective layer.

[0031] [3] The laminate according to [1] or [2], wherein the light transmittance of the transparent resin layer is 70% or more.

[0032] [4] The laminate according to any one of [1] to [3], wherein the material of the transparent resin layer comprises one or more of a polyester resin, a polycarbonate resin, a polyolefin resin, a polyacrylate resin, or modified products thereof.

[0033] [5] The laminate according to any one of [1] to [4], wherein the hot melt adhesive comprises one or more of PA hot melt adhesive, TPU hot melt adhesive, EVA hot melt adhesive or PES hot melt adhesive.

[0034] [6] The laminate according to any one of [1] to [5], wherein the reflective material layer includes a surface layer capable of forming a pattern, a support layer, a lens array layer, a focusing layer, a reflective layer, and an adhesive layer.

[0035] [7] The laminate according to any one of [1] to [6], wherein the material of the metal base material layer is selected from any one of aluminum, aluminum alloy, iron, and iron alloy.

[0036] [8]. Furthermore, the present invention also provides a vehicle number plate, wherein the vehicle number plate is obtained by processing the laminated body described in any one of [1] to [7] above.

[0037] [9]. The vehicle number plate according to [8], wherein the processing includes stamping.

[0038]

[0010] . The vehicle number plate according to [8] or [9], wherein the vehicle is a motor vehicle.

[0039] Effects of the Invention

[0040] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0041] (1) By using a hot melt adhesive with specific properties (instead of the currently commonly used pressure-sensitive adhesive) as the adhesive layer in the protective layer, when cutting the protective layer and punching the laminate, the adhesive layer of the cut and punched parts can be ensured to have excellent cutting properties, and at the same time, the protective layer / reflective material layer in other parts can be ensured not to crack.

[0042] (2) By optimizing the thickness of the transparent resin layer and the thickness of the adhesive layer in the protective layer, it is possible to ensure the cutting properties while taking into account the toughness of the entire protective layer.

[0043] (3) The method of the present invention can avoid the use of varnish ink as a protective layer, thereby avoiding the volatilization of harmful gases and reducing energy and space consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1: Structural diagram of a laminate in a specific embodiment of the present invention

[0045] A: Protective layer; B: Reflective material layer; C: Metal substrate layer

[0046] 1: Transparent resin layer; 2: Adhesive layer (hot melt adhesive); 3: Surface layer; 4: Support layer;

[0047] 5: Lens array layer; 6: Focusing layer; 7: Reflection layer; 8: Adhesive layer.

[0048] Figure 2: Structural diagram of the reflective material layer in a laminate according to a specific embodiment of the present invention

[0049] 2-1: surface layer; 2-2: air chamber; 2-3: lens array layer (glass beads);

[0050] 2-4: Reflective layer; 2-5 Support layer; 2-6: Adhesive layer

[0051] Figure 3: Structural diagram of the reflective material layer in a laminate according to a specific embodiment of the present invention

[0052] 3-1: surface layer; 3-2: lens array layer (prism); 3-3: reflection layer;

[0053] 3-4: Adhesive layer

[0054] Figure 4: Structural diagram of the reflective material layer in a laminate according to a specific embodiment of the present invention

[0055] 4-1: surface layer; 4-2: lens array layer (prism); 4-3: air chamber;

[0056] 4-4: support layer; 4-5 adhesive layer

[0057] Figure 5: In a specific embodiment of the present invention, the structure of the laminate after stamping

[0058] A: Protective layer; B: Reflective material layer; C: Metal substrate layer DETAILED DESCRIPTION

[0059] The following is a detailed description of the present invention. The following description of the technical features is 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:

[0060] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0061] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0062] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0063] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0064] In this specification, the use of “substantially” or “essentially” means that the standard deviation from a theoretical model, theoretical data or target data is within a numerical range of 5%, preferably 3%, and more preferably 1%.

[0065] When the terms “include” and / or “comprising” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0066] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0067] The present invention primarily provides a laminate for a vehicle number plate, which can be processed into a final number plate through subsequent processing such as stamping.

[0068] The laminate comprises, in sequence, a protective layer, a reflective material layer, and a metal substrate layer. The term "in sequence" used here simply refers to the order of stacking and does not limit the laminate to only comprising the above three layers.

[0069] (vehicle)

[0070] The vehicle described in the present invention may be a motor vehicle, a non-motor vehicle, or other vehicles with various special functions.

[0071] Preferably, the vehicle of the present invention refers to a motor vehicle, which includes motor vehicles powered by petrochemical energy and motor vehicles powered by new energy (hydrogen energy, lithium batteries, hybrid power).

[0072] (Protective layer)

[0073] The protective layer of the present invention mainly plays a role in protecting the laminate, especially protecting the pattern on the surface of the reflective material layer on the laminate, so as to increase the durability of the final vehicle number plate.

[0074] Such a protective layer mainly includes a transparent resin layer located at the outermost layer of the laminate and an adhesive layer for bonding the transparent resin layer and the reflective material layer.

[0075] Transparent resin layer

[0076] In principle, there is no particular limitation on the transparent resin layer that can be used in the present invention, as long as it provides sufficient light transmittance. In some specific embodiments, the transparent resin layer is made of a material including a transparent resin and an optional auxiliary agent.

[0077] As for the transparent resin, in some specific embodiments of the present invention, it can be selected from one or more of polyester resins, polycarbonate resins, polyolefin resins, polyacrylate resins, or modified products thereof.

[0078] The polyester resin may be a condensate of an aliphatic, aromatic or alicyclic diol and a diacid, preferably PET, PBT, etc.

[0079] The polyolefin resin may be a homopolymer of olefin, a copolymer of multiple olefins, or a copolymer of olefin and other polymerizable monomers, such as ethylene-vinyl acetate copolymer.

[0080] The acrylic ester resin may be a polymer of one or more (meth)acrylates.

[0081] The modification mentioned above may include modification of the main chain or side chain of the resin. In some preferred embodiments, the modification includes introduction of halogen atoms, organosilicon structures, and the like.

[0082] Furthermore, there are no particular limitations on the additives 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. Furthermore, in some cases, the transparent resin layer may be coated with a protective release layer before leaving the factory. To ensure adequate release properties, additives such as silicone oil, talc, and wax may also be used.

[0083] The thickness of the transparent resin layer of the present 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 may not provide good mechanical properties and weather resistance. For example, during the subsequent stamping process to produce the license plate, the transparent resin layer may crack. If the transparent resin layer is too thick, it may result in poor cutting performance.

[0084] The light transmittance of the transparent resin layer of the present invention mainly refers to the total light transmittance of light in the visible light band. In some preferred embodiments, under 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.

[0085] Adhesive layer

[0086] The adhesive layer of the present invention is used to bond the transparent resin layer and the reflective material layer (the surface layer). The adhesive layer of the present invention mainly comprises a hot melt adhesive.

[0087] In some specific embodiments, the content of the 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.

[0088] In the most preferred embodiment, the adhesive layer of the present invention is formed substantially entirely of a hot melt adhesive.

[0089] The hot melt adhesive of the present invention has a melting point of 110°C to 250°C, preferably 130°C to 220°C, and more preferably 140°C to 210°C. A too low melting point will result in poor shearing properties 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 material layer. A too high melting point may lead to difficulties in processing and use, or uneven bonding.

[0090] The "melting point" of the present invention is the temperature at which the hot melt adhesive reaches its lowest viscosity when heated from low to high.

[0091] 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. A thickness that is too low results in poor mechanical strength and adhesion, while a thickness that is too high may lead to uneven bonding and poor shearing properties.

[0092] Compared with the pressure-sensitive adhesive commonly used in the prior art, the hot melt adhesive used in the present invention has better adhesion while also being able to balance the relationship between toughness and cutting properties, and has better workability.

[0093] (Reflective material layer)

[0094] In principle, there is no particular limitation on the reflective material layer that can be used in the present invention, and conventional commercially available materials in the art can be used.

[0095] These reflective layers can be commercially available encapsulated glass microbead reflective sheeting, glass microbead capsule reflective sheeting, or prismatic reflective sheeting, such as NIKKALITE brand SCL, ELG, FMG, UL, CRG, and ECE grades from ENSI (Hangzhou) Film Co., Ltd. In other words, the reflective surface can be PVC, PU, ​​acrylic resin, PMMA, or PC, and the retroreflective structure can be either microbead or prismatic.

[0096] In some preferred embodiments, the reflective material layer includes a surface layer capable of forming a pattern, a support layer, a transparent array layer, a focusing layer, a reflective layer, and an adhesive layer (as shown in FIG. 1 ).

[0097] surface layer

[0098] The surface layer mentioned above can usually be a transparent layer, and the surface layer allows various patterns to be formed by printing, etc., or such patterns can also be embedded in such a transparent layer.

[0099] For such a surface layer, in some specific embodiments, its material can 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. Considering suitability during coloring or dispersibility during coloring with a colorant, acrylic resin is preferred.

[0100] In some other specific embodiments, a colored pigment or dye may be added to the resin in the surface layer, and the pigment or dye is preferably a transparent pigment. The pigment or dye colorant may be as follows:

[0101] Yellow: colorants such as isoindolinone, isoindolinone, quinophthalone, anthraquinone, pyrazolone, flavanone, benzimidazolone, and azonickel;

[0102] Red: anthraquinone-based, perylene-based, quinacridone-based, indigo-based, and other colorants;

[0103] Blue: phthalocyanine series, onium vat dyeing series, anthraquinone series, cobalt series and other colorants;

[0104] Green: phthalocyanine, emerald green, chromium oxide, cadmium and other colorants;

[0105] Brown: iron red series colorant, or combined with isoindolinone series yellow colorant, perylene series red colorant and phthalocyanine series blue colorant;

[0106] Orange: Single-color colors include anthraquinone series, pyrazolone series, perinone series, perylene series, and quinacridone series. Isoindolone series yellow colorants and perylene series red colorants can also be used in combination.

[0107] White: phthalein, zinc, lead, etc. colorants;

[0108] Black: Colorants such as carbon black, aniline black, perylene black, and titanium black.

[0109] Furthermore, in some specific embodiments, the thickness of the surface layer may be 10 μm to 150 μm, preferably 20 μm to 60 μm, and most preferably 30 μm to 50 μm.

[0110] Support layer

[0111] Similar to the above-mentioned surface layer, 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 during coloring or dispersibility during coloring with a colorant, acrylic resin is preferred.

[0112] Likewise, it may have the same colored pigments or dyes as the surface layer.

[0113] lens array layer

[0114] The lens array layer of the present invention can be a lens array layer formed of light-transmitting microbeads or prisms. In some specific embodiments, the lens array layer is at least partially embedded in two adjacent layers above and below it, for example, the lens array layer is partially embedded in both the support layer and the focusing layer described below.

[0115] Furthermore, for the lens array layer of the present invention, it is preferred that the lens array be a structural layer having retroreflective properties.

[0116] In some specific embodiments, the lens units included in the lens array are of any shape with a refractive function, such as light-transmitting microbeads or prisms. In some specific embodiments, the light-transmitting microbeads can be spherical, rod-shaped, ellipsoidal, or any combination thereof; in other specific embodiments, the prisms are sawtooth (triangular) prisms.

[0117] The material of the microbeads or prisms is composed of at least one of glass, ceramics, polymers, and minerals. 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 microbeads is 10 μm to 150 μm, preferably 50 μm to 110 μm, and most preferably 60 μm to 110 μm.

[0118] Focus Layer

[0119] The focusing layer of the present invention is a transparent focusing layer. In principle, there is no particular limitation on its material and structure. It is mainly used to focus the reflected light, thereby visually improving the clarity of the reflecting surface.

[0120] 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.

[0121] 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, and such a curved surface provides a focusing effect by being concave toward the structure of the opaque layer.

[0122] reflective layer

[0123] As the reflective layer of the present invention, a metallic reflective film commonly used in the art can be used.

[0124] In some specific embodiments, it may be a metal film, such as a film of aluminum (Al), silver (Ag), or gold (Au).

[0125] In some other specific embodiments, it can be a coating, that is, coating the surface of a metal or resin film with highly reflective metals such as aluminum (Al), silver (Ag), gold (Au), etc.

[0126] adhesive layer

[0127] The material of the adhesive layer of the present invention is not particularly limited, and commonly used pressure-sensitive adhesives in the art, such as (meth)acrylic pressure-sensitive adhesives, can be used. Alternatively, the adhesive layer can be formed of a hot melt adhesive. However, from the perspective of removability, pressure-sensitive adhesives are preferably used.

[0128] In the case of using a pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive may be 10 μm to 150 μm, preferably 20 μm to 60 μm, and most preferably 30 μm to 50 μm.

[0129] The hot melt adhesive may 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 may be 1 μm to 150 μm, preferably 3 μm to 40 μm, and most preferably 6 μm to 30 μm.

[0130] In some other specific embodiments, the reflective material layer of the present invention may also adopt other existing structures, such as the structures shown in FIG. 2 to FIG. 4 .

[0131] In FIG. 2 and FIG. 4 , the lens array layer is (partially) placed in an air chamber, while in FIG. 3 and FIG. 4 , the lens array layer is arranged in the form of a prism layer.

[0132] (Metal substrate layer)

[0133] In principle, there is no particular limitation on the metal substrate layer of the present invention, and various stampable metal substrates can be selected according to needs or local regulations.

[0134] In some specific embodiments, the material of the metal substrate layer can be selected from any one of aluminum, aluminum alloy, iron, iron alloy, etc.

[0135] (Preparation of vehicle number plates)

[0136] The vehicle number plate of the present invention is obtained by processing the above-mentioned laminate. In some preferred embodiments, the above-mentioned processing includes:

[0137] First, a roll-to-roll inkjet printer prints the pattern on a reflective material. The roll of reflective material is then attached to an aluminum plate. The aluminum plate is then punched out to the size of the license plate. The plate is then sent to a hot stamping machine to be hot-stamped with a protective layer. The plate, now hot-stamped, is then sent to a plate stamping machine to be stamped with the characters. The reflective material and protective layer are then removed from the surface of the characters. The color of the number plate characters is then roller-coated or hot-stamped.

[0138] The process of the hot stamping protective layer of the present invention can be specifically listed as follows:

[0139] The hot stamping machine's processing speed is between 1 and 10 m / min, with an optimal range of 2 to 5 m / min. Assuming the thickness of the vehicle number plate is at least 1.1 mm, the ideal distance between the hot stamping machine's rubber heated roller and the metal roller below is 0.7 to 1 mm. The hot stamping temperature is between 130°C and 250°C, with an optimal range of 180°C to 200°C. This temperature is not the machine's set temperature, but the surface temperature of the rubber roller before hot stamping, and the temperature remains stable during hot stamping.

[0140] The above process provides excellent shear resistance during hot stamping. After hot stamping, the hot stamped motor vehicle number plate does not crack or fall off during the stamping process.

[0141] Example

[0142] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0143] Example 1

[0144] Using a MIMAKI JV33 roll-to-roll inkjet printer, the desired design is printed on L851200LK reflective material from NCI (Hangzhou) Film Co., Ltd. The reflective material is then bonded to the aluminum plate used for the license plate. A punch press equipped with a semi-finished license plate mold (with the license plate shape and mounting holes) is then used to stamp the semi-finished product. A transparent protective layer (hot melt adhesive with a melting point of 150°C and a thickness of 12μm; the transparent resin layer is 15μm) is then applied using a hot stamping machine. The hot stamping machine speed is set at 3m / min, and the hot stamping roller temperature is 190°C. The stamped license plate is then stamped again using a number plate character stamping machine. The stamped license plate characters are then either roller-coated or hot stamped.

[0145] Example 2

[0146] L851200LK reflective material from NCI (Hangzhou) Film Co., Ltd. is laminated to the aluminum plate used for license plates. The semi-finished plate is then punched out using a punch press equipped with a mold for the plate's shape and mounting holes. The desired design is then printed on a MIKAKI UJV-160 flatbed inkjet printer. A transparent protective layer (hot melt adhesive with a melting point of 150°C and a thickness of 12μm; the transparent resin layer is 15μm) is then applied using a hot stamping machine. The hot stamping machine speed is set at 3m / min, and the hot stamping roller temperature is 190°C. The stamped number plate is then stamped again using a number plate character stamping machine. The stamped number plate's character color is then either roller-coated or hot stamped.

[0147] Comparative Example 1:

[0148] Same as Example 1, except that the melting point of the hot melt adhesive is 100°C;

[0149] Comparative Example 2

[0150] Same as Example 1, except that the hot melt adhesive thickness is 25 μm;

[0151] Comparative Example 3

[0152] Same as Example 1, except that the thickness of the transparent resin layer is 0.2 μm;

[0153] Comparative Example 4

[0154] Same as Example 1, except that the thickness of the transparent resin layer is 28 μm.

[0155] Results comparison:

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

[0157] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not 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 selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A laminate for a vehicle number plate, characterized in that: The stacked body comprises in sequence: Protective layer, reflective material layer and metal substrate layer, in, The protective layer includes a transparent resin layer and an adhesive layer. The thickness of the transparent resin layer is 0.5 to 20 μm, and the thickness of the adhesive layer is 0.5 to 20 μm. The adhesive layer includes a hot melt adhesive having a melting point of 110° C. to 250° C.

2. The laminate according to claim 1, wherein The protective layer is a hot stamping layer; and a pattern layer is further provided on the surface of the reflective material layer adjacent to the protective layer.

3. The laminate according to claim 1 or 2, wherein: The light transmittance of the transparent resin layer is greater than 70%.

4. The laminate according to any one of claims 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 products thereof.

5. The laminate according to any one of claims 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.

6. The laminate according to any one of claims 1 to 5, wherein The reflective material layer includes a surface layer capable of forming a pattern, a supporting layer, a lens array layer, a focusing layer, a reflective layer and an adhesive layer.

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

8. A vehicle number plate, characterized in that: The vehicle number plate is obtained by processing the laminate according to any one of claims 1 to 7.

9. The vehicle number plate according to claim 8, characterized in that: The processing includes stamping processing.

10. The vehicle number plate according to claim 8 or 9, characterized in that: The vehicle is a motor vehicle.

Images