Hot stamping film for vehicle license plate

Abstract

The invention provides a hot stamping film for a vehicle license plate. The hot stamping film for the vehicle license plate does not comprise a release layer or a release agent, so that the bad problems of poor secondary hot stamping adherence and the like caused by the release agent or the release layer are solved, and excellent hot stamping adherence is realized. In addition, according to the hot stamping film for the vehicle license plate, a release layer structure is reduced, so that the production cost is also reduced. Besides, after the hot stamping film for the vehicle license plate is transferred to the vehicle license plate, the firmness is excellent, the weather resistance and the solvent resistance are excellent, and the hot stamping film can adapt to severe and complex construction environments.

Description

Technical Field

[0001] The invention relates to a hot stamping film for a vehicle number plate, in particular to a hot stamping film for a vehicle number plate which does not include a release layer or a release agent. Background Art

[0002] In order to solve the environmental problem, the motor vehicle license plate has changed from the original ink printing method to the hot stamping method for new energy motor vehicle license plates, because the hot stamping method is more environmentally friendly than the original ink printing method. The hot stamping process includes: using a hot stamping machine to use the temperature and pressure of the roller to soften the hot stamping layer and bond it to the substrate in a short time.

[0003] The hot stamping film consists of two layers, one is the PET film of the base material, and the other is the hot stamping layer that is finally stamped onto the motor vehicle license plate. The hot stamping layer is separated from the base material layer (PET) by heating and softening on the side close to the base material layer (PET), while the adhesive layer on the opposite side is combined with the motor vehicle license plate by heating and softening. Finally, the hot stamping layer combined with the motor vehicle license plate remains on the motor vehicle license plate, while the other layers remain on the base material film. Motor vehicle license plates use reflective film, and the surface layer of the reflective film varies depending on the manufacturer, and can be PVC, acrylic, PU, ​​etc. For the convenience of processing, motor vehicle license plate manufacturers generally keep the hot stamping film unchanged, while the reflective film used for motor vehicle license plates has different models from different manufacturers.

[0004] According to the requirements of the hot stamping process, the hot stamping layer needs to be separated from the substrate layer during hot stamping. Therefore, in order to facilitate hot stamping on the motor vehicle license plate and the hot stamping film is easily separated from the substrate, a release layer is generally provided. From the existing technology, the release layer and the transparent protective layer are usually combined together.

[0005] Patent document 1 discloses a thermal transfer film for motor vehicle license plates and its manufacturing method and application, including a PET base film layer and a thermal transfer layer, the PET base film layer and the thermal transfer layer are connected to each other, the thermal transfer layer includes a release layer, a color layer and a back adhesive layer connected in sequence, the release layer is made of thermoplastic acrylic resin A, polyethylene wax slurry, ultraviolet absorber, and light stabilizer, the color layer is made of toner, vinyl chloride-vinyl acetate-vinyl alcohol terpolymer, dispersant, and acrylic resin B, and the back adhesive layer is made of chlorinated polypropylene resin, chloroacetic acid resin, phenolic resin, and silicon powder. Patent document 1 uses the above design to enable the thermal transfer film to be hot-stamped at low temperature, with high production efficiency, high hot-stamping fastness, high hot-stamping stability, and low hot-stamping energy consumption. However, Patent document 1 does not disclose that two layers can be hot-stamped, that is, as long as the pigment layer and the hot-stamping adhesive layer other than the base film layer can be hot-stamped and meet the performance requirements of motor vehicle license plates.

[0006] Patent document 2 discloses that the thermal transfer film includes a tape base and a lubricating layer and a thermal transfer layer respectively arranged on both sides thereof; the thermal transfer layers are inner coating, cross-linking curing layer, color layer and top coating layer from close to the tape base to far from the tape base; the inner coating layer includes ethylene-hydroxyethyl acrylate copolymer, styrene-maleic anhydride copolymer, polytetrafluoroethylene wax micropowder, and antioxidant; the cross-linking curing layer includes melamine formaldehyde resin, polyether polyol, and silica matting powder; the color layer includes terpene phenolic resin, hydrogenated petroleum resin, and carbon black; the top coating layer includes high chlorinated polyethylene resin, styrene-butadiene-styrene block copolymer, and asphalt. The thermal transfer film of patent document 2 is used to make vehicle license plates, which is firm and reliable, has excellent weather resistance and chemical resistance, and can adapt to a variety of harsh and complex construction environments. However, patent document 2 does not disclose that two layers can achieve hot stamping, that is, as long as the pigment layer and the hot stamping adhesive layer other than the base film layer can achieve hot stamping and meet the performance requirements of motor vehicle license plates.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent document 1: CN115339254A

[0010] Patent document 2: CN112852247B Summary of the invention

[0011] Problem that the invention aims to solve

[0012] The heating method of hot stamping process is mainly to heat the rubber outside or inside the metal roller with rubber skin. The processes of various hot stamping machine manufacturers are different, and the heating temperature and actual temperature are different. In particular, as the rubber is used for a long time, the hardness changes, and the heat transfer effect decreases, it will affect the hot stamping.

[0013] Therefore, in the existing hot stamping process, there will be some small defects. For these small defects, sometimes two hot stampings are needed to cover the original defects. In order to facilitate the release of the hot stamping film from the substrate layer, the current hot stamping film usually uses a release agent. The release agent used will result in poor adhesion during the second hot stamping.

[0014] The present invention is made to solve the above-mentioned existing problems, and its purpose is to provide a hot stamping film for vehicle license plates, which does not include a release layer or a release agent, thereby being able to solve the above-mentioned problems such as poor secondary hot stamping adhesion caused by the release agent or the release layer, and achieve excellent hot stamping adhesion. In addition, since the hot stamping film for vehicle license plates of the present invention reduces the release layer structure, the production cost is also reduced. Here, even if the hot stamping film for vehicle license plates of the present invention does not include a release layer, it has excellent wear resistance.

[0015] Solutions for solving problems

[0016] The present inventors have conducted intensive studies to solve the above problems and have found that a hot stamping film for a vehicle number plate that does not include a release layer or a release agent can solve the above problems, thereby completing the present invention.

[0017] That is, the present invention is as follows.

[0018] [1]. A hot stamping film for a vehicle license plate, wherein the hot stamping film for a vehicle license plate comprises: a substrate layer, a color layer disposed on one side of the substrate layer, and an adhesive layer disposed on a side of the color layer opposite to the substrate layer,

[0019] Wherein, the hot stamping film for vehicle license plates does not include a release layer or a release agent.

[0020] [2] The hot stamping film for vehicle license plates according to [1], wherein the substrate layer satisfies one or more of the following conditions:

[0021] (1) The substrate layer is a polyethylene terephthalate substrate layer;

[0022] (2) The thickness of the substrate layer is 16 to 30 μm.

[0023] [3] The hot stamping film for vehicle license plates according to [1] or [2], wherein the color layer satisfies one or more of the following conditions:

[0024] (a) the color layer is formed of a color composition, the color composition comprising a resin and a colorant;

[0025] (b) the resin comprises vinyl chloride-vinyl acetate copolymer,

[0026] The vinyl chloride-vinyl acetate copolymer has a weight average molecular weight of 10,000 to 150,000, a glass transition temperature of 80° C. or less, and a softening point of less than 100° C.;

[0027] (c) the colorant comprises a pigment colorant or a dye colorant;

[0028] (d) the color composition further comprises at least one selected from a surfactant, a dispersant, a defoaming agent, an organic solvent and talc;

[0029] (e) The thickness of the color layer is 0.5 to 10 μm.

[0030] [4] The hot stamping film for vehicle license plates according to [1] or [2], wherein the adhesive layer satisfies one or more of the following conditions:

[0031] (i) the adhesive layer is formed of an adhesive layer composition, wherein the adhesive layer composition comprises at least one selected from an adhesive, an organic solvent, a resin and a colorant;

[0032] (ii) the adhesive comprises a thermoplastic acrylic,

[0033] The thermoplastic acrylic acid has a weight average molecular weight of 1,000 to 100,000, a glass transition temperature of 80° C. or less, a softening point of greater than 100° C., a hydroxyl value of 7 to 13 mgKOH / g, and an acid value of 17 to 23 mgKOH / g;

[0034] (iii) the organic solvent comprises ethyl acetate;

[0035] (iv) the resin comprises a non-crystalline polyester and / or a vinyl chloride-vinyl acetate copolymer,

[0036] The non-crystalline polyester has a weight average molecular weight of 10,000 to 100,000, a glass transition temperature of 30° C. or less, a hydroxyl value of 5 to 11 mgKOH / g, and an acid value of less than 2 mgKOH / g;

[0037] (v) The thickness of the adhesive layer is 0.5 to 10 μm.

[0038] [5] A method for manufacturing a hot stamping film for a vehicle license plate according to any one of [1] to [4], wherein the manufacturing method comprises:

[0039] Step A: coating a color composition on a substrate layer and drying to form a color layer;

[0040] Step B: coating the adhesive layer composition on the color layer and drying to form an adhesive layer.

[0041] [6] The manufacturing method according to claim 5, wherein:

[0042] In the step A, the drying temperature is 60 to 120° C. and the drying time is 0.5 to 5 min;

[0043] In the above step B, the drying temperature is 60 to 120° C., and the drying time is 0.5 to 5 minutes.

[0044] [7] The method according to [5] or [6], wherein the color composition comprises at least one selected from the group consisting of a resin, a colorant, a surfactant, a dispersant, a defoaming agent, an organic solvent and talc;

[0045] The adhesive layer composition comprises at least one selected from the group consisting of an adhesive, an organic solvent, a resin and a colorant.

[0046] [8]. A method for manufacturing a vehicle license plate, comprising: performing hot stamping using the hot stamping film for a vehicle license plate according to any one of [1] to [4].

[0047] [9]. Use of the hot stamping film for vehicle license plates according to any one of [1] to [4] to improve the hot stamping adhesion and / or wear resistance in the manufacture of vehicle license plates.

[0048] Effects of the Invention

[0049] The hot stamping film for vehicle number plates of the present invention does not include a release layer or a release agent, thereby solving the problem of poor secondary hot stamping adhesion due to the release agent or the release layer, and achieving excellent hot stamping adhesion. In addition, since the hot stamping film for vehicle number plates of the present invention reduces the release layer structure, the production cost is also reduced. In addition, even if the hot stamping film for vehicle number plates of the present invention does not include a release layer, it has excellent wear resistance.

[0050] After the hot stamping film for vehicle license plates of the present invention is transferred to the vehicle license plates, it has excellent firmness, weather resistance, solvent resistance and abrasion resistance, and can adapt to harsh and complex construction environments and application environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a cross-sectional view schematically showing the structure of the hot stamping film for vehicle number plates of the present invention.

[0052] Figure 2 is a photograph showing the abrasion resistance results of the hot stamping film of Example 1.

[0053] Figure 3 This is a photograph showing the abrasion resistance results of the hot stamping film of Comparative Example 1.

[0054] Description of Reference Numerals

[0055] 10 Hot stamping film for vehicle license plates

[0056] 1. Substrate layer

[0057] 2 Color Layers

[0058] 3. Adhesive 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 numerical values ​​A and B.

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

[0062] In this specification, the word "may" means both performing a certain process and 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 the present 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] In this specification, when the terms “include” and / or “comprise” are used, they indicate the existence of features, steps, operations, devices, components and / or their combinations.

[0066] In this specification, the 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 exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0067] <Hot stamping film for vehicle license plates>

[0068] In a first aspect of the present invention, a hot stamping film for a vehicle license plate is provided, comprising: a substrate layer, a color layer arranged on one side of the substrate layer, and an adhesive layer arranged on a side of the color layer opposite to the substrate layer, wherein the hot stamping film for a vehicle license plate does not include a release layer or a release agent.

[0069] The vehicle described in the present invention may be a motor vehicle, a non-motor vehicle, or other vehicles with various special functions.

[0070] In some preferred embodiments, 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).

[0071] In the present invention, the hot stamping film for vehicle number plates does not include a release layer or a release agent, thereby solving the problem of poor secondary hot stamping adhesion due to the release agent or release layer, and achieving excellent hot stamping adhesion. In addition, since the hot stamping film for vehicle number plates of the present invention reduces the release layer structure, the production cost is also reduced. In addition, the hot stamping film for vehicle number plates of the present invention has excellent wear resistance even if it does not include a release layer.

[0072] In some preferred embodiments, the hot stamping film for vehicle license plates of the present invention consists only of a substrate layer, a color layer and an adhesive layer.

[0073] Figure 1 FIG. 2 is a cross-sectional view schematically showing the structure of a hot stamping film for a vehicle license plate according to an embodiment of the present invention. Figure 1 As shown, the hot stamping film 10 for vehicle license plates includes: a substrate layer 1, a color layer 2 arranged on one side of the substrate layer 1, and an adhesive layer 3 arranged on the side of the color layer 2 opposite to the substrate layer 1.

[0074] In some preferred embodiments, the color layer 2 is preferably disposed on the entire surface of the substrate layer 1 , and the adhesive layer 3 is preferably disposed on the entire surface of the color layer 2 .

[0075] (Base material layer)

[0076] The substrate layer serves as a carrier of the hot stamping film for vehicle license plates, providing protection and support.

[0077] In some preferred embodiments, the substrate layer is preferably a polyethylene terephthalate (PET) substrate layer.

[0078] In some preferred embodiments, the thickness of the substrate layer is 16 to 30 μm, preferably 19 to 25 μm. If the thickness of the substrate layer is less than 16 μm, it is easy to wrinkle when heated for hot stamping, resulting in poor hot stamping performance and failure to provide good mechanical properties and weathering protection. If the thickness of the substrate layer is greater than 30 μm, it will affect the hot stamping temperature, slow heat transfer, and poor hot stamping performance.

[0079] In some specific embodiments, the thickness of the substrate layer is 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm.

[0080] The surface of the substrate layer may be subjected to a surface treatment as required. Examples of the surface treatment include frosting treatment. From the viewpoint of weather resistance of the surface layer of the hot stamping film, the surface of the substrate layer is preferably subjected to frosting treatment.

[0081] (Color layer)

[0082] Color layers are used to achieve specific colors.

[0083] In some preferred embodiments, the color layer is formed from a color composition.

[0084] In some preferred embodiments, the color composition comprises a resin and a colorant.

[0085] Examples of the resin include vinyl chloride vinyl acetate copolymers and acrylic resins. In terms of suitability during coloring and dispersibility during coloring with a colorant, vinyl chloride vinyl acetate copolymers are preferred.

[0086] The weight average molecular weight of the vinyl chloride vinyl acetate copolymer is preferably 10,000 to 150,000, the glass transition temperature (Tg) is preferably 80° C. or less, more preferably 59 to 79° C., and further preferably 69° C., and the softening point is preferably less than 100° C. When the vinyl chloride vinyl acetate copolymer is used as the resin in the color layer, the colorant can be effectively encapsulated, and the color layer has better solvent resistance, thereby further improving the stability of the hot stamping film.

[0087] As a colorant, a pigment or dye colorant can be used. As a pigment or dye colorant, it can be as follows:

[0088] Yellow: colorants of isoindolinone, isoindolinone, quinophthalone, anthraquinone, pyrazolone, flavanone, benzimidazolone, azonickel, etc.

[0089] Red: anthraquinone, perylene, quinacridone, indigo and other colorants;

[0090] Blue: phthalocyanine, vat dyeing, anthraquinone, cobalt and other colorants;

[0091] Green: colorants of phthalocyanine series, emerald green series, chromium oxide series, cadmium series, etc.

[0092] Brown: iron red series colorant, or isoindolinone series yellow colorant, perylene series red colorant and phthalocyanine series blue colorant;

[0093] Orange: Monochrome colors include anthraquinone series, pyrazolone series, perindolone series, perylene series, and quinacridone series. You can also use isoindolinone series yellow colorants and perylene series red colorants together.

[0094] White: phthalate, zinc, lead, etc. colorants;

[0095] Black: Colorants such as carbon black, aniline black, perylene black, and titanium black.

[0096] In some preferred embodiments, the color composition preferably further comprises at least one selected from the group consisting of a surfactant, a dispersant, a defoaming agent, an organic solvent and talc.

[0097] As a surfactant, dizinc sulfosuccinate sodium salt is mentioned, for example.

[0098] As an organic solvent, cyclohexanone is mentioned, for example.

[0099] In some preferred embodiments, based on 100 parts by weight of the total composition of the color composition, the content of the resin is 12 to 48 parts by weight, the content of the colorant is 12 to 48 parts by weight, the content of the surfactant is 0.1 to 3 parts by weight, the content of the dispersant is 0.1 to 3 parts by weight, the content of the defoaming agent is 0 to 3 parts by weight, the content of the organic solvent is 39 to 75 parts by weight, and the content of talc is 0 to 3 parts by weight.

[0100] By setting the content of the above components in the color composition within the above range, the color of the color layer can be made more uniform, and the hot stamping film has excellent transfer characteristics and print appearance in the transfer process and also has excellent solvent resistance.

[0101] In some preferred embodiments, the thickness of the color layer is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, and further preferably 1.5 to 5 μm. If the thickness of the color layer is less than 0.5 μm, the hiding power is insufficient and the solvent resistance is poor. If the thickness of the color layer is greater than 10 μm, it is easy to cause the hot stamping temperature to be too high, and the transfer characteristics and the imprint appearance will deteriorate.

[0102] In some specific embodiments, the color layer has a thickness of 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0103] (Glue layer)

[0104] In the present invention, the subbing layer is preferably formed of a subbing layer composition.

[0105] In some preferred embodiments, the subbing layer composition comprises an adhesive.

[0106] Examples of the adhesive include thermoplastic acrylic, EVA hot melt adhesive, PA hot melt adhesive, TPU hot melt adhesive, and PES hot melt adhesive, etc. These may be used alone or in combination of two or more.

[0107] In some preferred embodiments, the weight average molecular weight of the thermoplastic acrylic acid is preferably 1000 to 100000, the glass transition temperature (Tg) is preferably 80°C or less, more preferably 53 to 73°C, and further preferably 63°C, the softening point is preferably greater than 100°C, the hydroxyl value is preferably 7 to 13 mgKOH / g, more preferably 10 mgKOH / g, and the acid value is preferably 17 to 23 mgKOH / g, more preferably 20 mgKOH / g. By using the above thermoplastic acrylic acid, the adhesive property and the hot stamping property can be improved.

[0108] In some preferred embodiments, the glue layer composition further comprises a resin, a colorant and an organic solvent.

[0109] Examples of the resin include non-crystalline polyester and vinyl chloride-vinyl acetate copolymer.

[0110] In some preferred embodiments, the weight average molecular weight of the non-crystalline polyester is preferably 10,000 to 100,000, the glass transition temperature (Tg) is preferably 30°C or less, more preferably 3 to 20°C, and further preferably 8°C, the hydroxyl value is preferably 5 to 11 mgKOH / g, more preferably 8 mgKOH / g, and the acid value is preferably less than 2 mgKOH / g. By using the above non-crystalline polyester, the adhesive force and hot stamping performance of the adhesive layer can be improved.

[0111] As the vinyl chloride vinyl acetate and the colorant, for example, the vinyl chloride vinyl acetate and the colorant described in the above-mentioned color layer can be used.

[0112] As an organic solvent, ethyl acetate (EAC) is mentioned, for example.

[0113] In some preferred embodiments, based on 100 parts by weight of the total composition of the adhesive layer composition, the content of the adhesive is 10 to 90 parts by weight, the content of the organic solvent is 10 to 90 parts by weight, the content of the resin is 0 to 60 parts by weight, and the content of the colorant is 0 to 1.5 parts by weight.

[0114] By setting the content of the above components in the glue layer composition to be within the above range, excellent adhesive performance can be provided, and sufficient adhesive force can be provided to the vehicle license plate.

[0115] In some preferred embodiments, the thickness of the adhesive layer is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, and further preferably 1.5 to 5 μm. If the thickness of the adhesive layer is less than 0.5 μm, the adhesive force is too low and cannot provide suitable adhesion. If the thickness of the adhesive layer is greater than 10 μm, it is easy to cause the hot stamping temperature to be too high, and the transfer characteristics and imprint appearance will deteriorate.

[0116] In some specific embodiments, the thickness of the subbing layer is 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0117] <Method for manufacturing hot stamping film for vehicle license plate>

[0118] In a second aspect of the present invention, a method for manufacturing a hot stamping film for a vehicle license plate is provided, comprising:

[0119] Step A: coating a color composition on a substrate layer and drying to form a color layer;

[0120] Step B: coating the adhesive layer composition on the color layer and drying to form an adhesive layer.

[0121] Examples of the coating method include coating methods using a multicoater, a die coater, a gravure coater, an applicator, a rod coater, an air knife coater, a reverse roll coater, a lip coater, a dip coater, offset printing, flexographic printing, gravure printing, and screen printing.

[0122] As a drying method, heat drying etc. are mentioned, for example.

[0123] In the above step A, the drying temperature is preferably 60 to 120° C., and the drying time is preferably 0.5 to 5 minutes.

[0124] In the above step B, the drying temperature is preferably 60 to 120° C., and the drying time is preferably 0.5 to 5 minutes.

[0125] As the color composition and the glue layer composition, the color composition described in the above-mentioned color layer and the glue layer composition described in the above-mentioned glue layer can be used.

[0126] <Method for manufacturing vehicle number plate>

[0127] In a third aspect of the present invention, a method for manufacturing a vehicle license plate is provided, comprising: performing hot stamping using the hot stamping film for a vehicle license plate of the present invention.

[0128] In some preferred embodiments, a hot stamping machine is used to hot stamp the hot stamping film for the vehicle number plate.

[0129] In some preferred embodiments, the processing speed of the hot stamping machine is 1 to 10 m / min, preferably 2 to 5 m / min. Assuming that the thickness of the vehicle license plate is above 1.1 mm, the distance between the rubber heating roller on the hot stamping machine and the metal roller below is 0.7 to 1 mm. The hot stamping temperature is 130 to 250°C, preferably 180 to 200°C. The above temperature is not the equipment setting temperature, but the surface temperature of the rubber roller before hot stamping, and the temperature is stable during hot stamping.

[0130] <Use of hot stamping film for vehicle number plates to improve hot stamping adhesion and / or wear resistance in the manufacture of vehicle number plates>

[0131] In a fourth aspect of the present invention, there is provided use of a hot stamping film for vehicle number plates to improve hot stamping adhesion and / or wear resistance in manufacturing vehicle number plates.

[0132] Example

[0133] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0134] Example 1

[0135] A matte PET with a thickness of 20 μm manufactured by DuPont in Foshan, Guangzhou was used as the substrate.

[0136] 30 parts by weight of vinyl chloride-vinyl acetate copolymer, 15 parts by weight of color base (Black L0080), 0.1 parts by weight of sodium salt of dizinc sulfosuccinate, 0.1 parts by weight of dispersant (Lubrizol 32500), 0.1 parts by weight of defoamer (BYK 052), 0.1 parts by weight of talc and 54.6 parts by weight of cyclohexanone as a solvent were mixed and stirred to prepare a resin compound liquid for the color layer. Then, the resin compound liquid was applied on the above-mentioned PET layer. Thereafter, it was dried at 100°C for 5 minutes to form a color layer with a thickness of 2 μm.

[0137] 30 parts by weight of thermoplastic acrylic acid and 70 parts by weight of ethyl acetate (EAC) as a solvent were mixed, dissolved and stirred to prepare a resin compound liquid for the adhesive layer. The resin compound liquid was then applied to the color layer. After that, it was dried at 100°C for 5 minutes to form an adhesive layer with a thickness of 2 μm, thereby forming a hot stamping film for vehicle license plates. The evaluation results are shown in Table 1.

[0138] Example 2

[0139] A matte PET with a thickness of 20 μm manufactured by DuPont in Foshan, Guangzhou was used as the substrate.

[0140] 30 parts by weight of vinyl chloride-vinyl acetate copolymer, 15 parts by weight of color base (Black L0080), 0.1 parts by weight of sodium salt of dizinc sulfosuccinate, 0.1 parts by weight of dispersant (Lubrizol 32500), 0.1 parts by weight of defoamer (BYK 052), 0.1 parts by weight of talc and 54.6 parts by weight of cyclohexanone as a solvent were mixed and stirred to prepare a resin compound liquid for the color layer. Then, the resin compound liquid was applied on the above-mentioned PET layer. Thereafter, it was dried at 100°C for 5 minutes to form a color layer with a thickness of 2 μm.

[0141] 25 parts by weight of thermoplastic acrylic acid, 5 parts by weight of non-crystalline polyester (VYLON resin, manufactured by Toyobo Co., Ltd., Japan) and 70 parts by weight of ethyl acetate (EAC) as a solvent were mixed, dissolved and stirred to prepare a resin compound liquid for the adhesive layer. The resin compound liquid was then applied to the above-mentioned color layer. After that, it was dried at 100°C for 5 minutes to form an adhesive layer with a thickness of 2 μm, thereby forming a hot stamping film for vehicle license plates. The evaluation results are shown in Table 1.

[0142] Example 3

[0143] A matte PET with a thickness of 20 μm manufactured by DuPont in Foshan, Guangzhou was used as the substrate.

[0144] 30 parts by weight of vinyl chloride-vinyl acetate copolymer, 15 parts by weight of color base (Black L0080, manufactured by BASF), 0.1 parts by weight of sodium dizinc sulfosuccinate, 0.1 parts by weight of dispersant (Lubrizol 32500), 0.1 parts by weight of defoamer (BYK 052), 0.1 parts by weight of talc and 54.6 parts by weight of cyclohexanone as a solvent were mixed and stirred to prepare a resin compound liquid for the color layer. Then, the resin compound liquid was applied on the above-mentioned PET layer. Thereafter, it was dried at 100° C. for 5 minutes to form a color layer with a thickness of 2 μm.

[0145] 25 parts by weight of thermoplastic acrylic acid, 5 parts by weight of non-crystalline polyester (VYLON resin, manufactured by Toyobo Co., Ltd., Japan), 3 parts by weight of vinyl chloride-vinyl acetate copolymer, 1.5 parts by weight of colorant (Black L 0080, manufactured by BASF AG) and 65.5 parts by weight of ethyl acetate (EAC) as a solvent were mixed, dissolved and stirred to prepare a resin compound liquid for the adhesive layer. The resin compound liquid was then applied to the above-mentioned color layer. After that, it was dried at 100°C for 5 minutes to form an adhesive layer with a thickness of 2 μm, thereby forming a hot stamping film for vehicle license plates. The evaluation results are shown in Table 1.

[0146] Comparative Example 1

[0147] A biaxially oriented polyethylene terephthalate (PET) film with a thickness of 21 μm was used as the substrate. A release layer (acrylic modified silicone resin, with a silicone content of 20%, a thickness of 0.1 μm, purchased from Wacker Chemical (China) Co., Ltd.) was coated on one surface of the substrate and dried for later use.

[0148] Toluene and isopropanol were mixed in a volume ratio of 3:1 to obtain a mixed solvent. The mixed solvent was used to dissolve the following raw materials in weight percentage: 18.75% of ethylene-hydroxyethyl acrylate copolymer, 75% of styrene-maleic anhydride copolymer, 2.5% of polytetrafluoroethylene wax powder, and 3.75% of BHT antioxidant to prepare an inner coating composition, wherein the amount of the mixed solvent was 4 / 5 of the total mass of the ethylene-hydroxyethyl acrylate copolymer and the styrene-maleic anhydride copolymer. Then, the inner coating composition was applied to the other side surface of the above-mentioned substrate and dried at 120°C to form an inner coating with a thickness of 2 μm.

[0149] A crosslinking and curing layer composition was prepared by dissolving a mixture of the following raw materials in weight percentage: 44% melamine formaldehyde resin, 55% polyether polyol, and 1% silica matting powder using butanone, wherein the amount of butanone was 4 / 9 of the total mass of the melamine formaldehyde resin and the polyether polyol. Then, the crosslinking and curing layer composition was applied to the inner coating layer and dried at 100° C. to form a crosslinking and curing layer with a thickness of 1 μm.

[0150] A mixture of the following raw materials in weight percentages was dissolved in toluene: 36% terpene phenolic resin, 36% hydrogenated petroleum resin, and 28% carbon black, to prepare a color layer composition, wherein the amount of toluene was 2.5 times the total weight of the terpene phenolic resin and the hydrogenated petroleum resin. Then, the color layer composition was coated on the crosslinked cured layer and dried at 100° C. to form a color layer with a thickness of 2 μm.

[0151] Toluene was used to dissolve a mixture of the following raw materials in weight percentage: 39% of high chlorinated polyethylene resin, 28% of styrene-butadiene-styrene block copolymer, and 33% of asphalt to prepare a top coating composition, wherein the amount of toluene was 2 / 3 of the total weight of the high chlorinated polyethylene resin, styrene-butadiene-styrene block copolymer, and asphalt. Then, the top coating composition was applied on the color layer and dried at 120° C. to form a top coating layer with a thickness of 1 μm.

[0152] The inner coating layer, the cross-linked cured layer, the color layer and the top coating layer constitute a thermal transfer layer, thereby forming a thermal transfer film for a vehicle license plate.

[0153] <Evaluation Test>

[0154] The L8512 series reflective film of Encia (Hangzhou) Film Co., Ltd. was pasted on the aluminum plate and the Chinese license plate stamping characters were used to stamp out the license plate style. Then, the hot stamping machine of UTSCH Company of Germany was used for hot stamping. The speed was 4m / min, the gap between the metal roller and the rubber roller of the hot stamping machine was 1.8mm (the height of the license plate after hot stamping was 2mm), and the surface temperature of the rubber roller was 150℃, 170℃, and 190℃. Then, the evaluation was carried out according to the standard test of GAT 1083-2013 "Hot Stamping Film for Motor Vehicle License Plates". The score is a five-point system (1-5 points). The higher the score, the better the evaluation result, with score 1 being the worst and score 5 being the best.

[0155] Blot appearance:

[0156] The edges of the characters and border prints transferred to the surface of the license plate after hot stamping should be neat and free of burrs, the color of the printed surface should be uniform, and there should be no obvious defects such as peeling, warping, wrinkles, granular impurities, and missing printing.

[0157] The evaluation is conducted according to the following scoring criteria: the scoring is on a five-point scale (1-5 points), the higher the score, the better the evaluation result, with score 1 being the worst and score 5 being the best.

[0158] Adhesion performance:

[0159] After the adhesive tape peeling method test, the imprint should not fall off or warp.

[0160] The evaluation is conducted according to the following scoring criteria: the scoring is on a five-point scale (1-5 points), the higher the score, the better the evaluation result, with score 1 being the worst and score 5 being the best.

[0161] Solvent resistance:

[0162] Immerse the license plate sample in SAE40 lubricating oil, -20 diesel and 70 or above gasoline for 30 minutes respectively, take it out, wipe it dry and leave it for 1 hour. After the test, the imprint shall not show signs of fading, discoloration, fading, softening, wrinkling, blistering, cracking, delamination, curling or dissolution.

[0163] The evaluation is conducted according to the following scoring criteria: the scoring is on a five-point scale (1-5 points), the higher the score, the better the evaluation result, with score 1 being the worst and score 5 being the best.

[0164] Table 1

[0165]

[0166] It can be seen from Table 1 that the hot stamping films of Examples 1 to 3 not only have excellent hot stamping properties, but also can achieve excellent hot stamping adhesion, can solve the problem of poor secondary hot stamping adhesion due to the presence of a release agent or a release layer, and also have excellent solvent resistance.

[0167] In addition, the hot stamping film of Example 1 and the hot stamping film of Comparative Example 1 were evaluated for wear resistance as follows: the hot stamping film of Example 1 or the hot stamping film of Comparative Example 1 was placed under the grinding wheel using a TABER testing machine CS-10 grinding wheel, and a 100-cycle wear test was performed at a rotation speed of 30 r / min using the TABER testing machine.

[0168] like Figure 2 As shown, even though the hot stamping film of Example 1 does not include a release layer, it does not show whitening after 100 cycles of wear test, has excellent wear resistance, and can be widely used in environments such as harsh cleaning environments or frequent cleaning.

[0169] And as Figure 3 As shown, the hot stamping film of Comparative Example 1 showed obvious whitening after 100 cycles of wear test, and had poor wear resistance, and was not suitable for use in environments such as harsh cleaning environments or frequent cleaning.

[0170] Industrial Applicability

[0171] The hot stamping film for vehicle number plates of the present invention does not include a release layer or a release agent, thereby solving the problem of poor secondary hot stamping adhesion due to the presence of a release agent or a release layer, and achieving excellent hot stamping adhesion. In addition, since the hot stamping film for vehicle number plates of the present invention reduces the release layer structure, the production cost is also reduced. In addition, even if the hot stamping film for vehicle number plates of the present invention does not include a release layer, it has excellent wear resistance. After the hot stamping film for vehicle number plates of the present invention is transferred to the vehicle number plates, it has excellent firmness, and also has excellent weather resistance, solvent resistance and wear resistance, and can adapt to harsh and complex construction environments and application environments.

Claims

1. A hot stamping film for vehicle license plates, It is characterized in that The hot stamping film for vehicle license plates comprises: a substrate layer, a color layer arranged on one side of the substrate layer, and an adhesive layer arranged on a side of the color layer opposite to the substrate layer. Wherein, the hot stamping film for vehicle license plates does not include a release layer or a release agent.

2. The hot stamping film for vehicle license plate according to claim 1, It is characterized in that The substrate layer satisfies one or more of the following conditions: (1) The substrate layer is a polyethylene terephthalate substrate layer; (2) The thickness of the substrate layer is 16 to 30 μm.

3. The hot stamping film for vehicle license plate according to claim 1 or 2, It is characterized in that The color layer meets one or more of the following conditions: (a) the color layer is formed of a color composition, the color composition comprising a resin and a colorant; (b) the resin comprises vinyl chloride-vinyl acetate copolymer, The vinyl chloride-vinyl acetate copolymer has a weight average molecular weight of 10,000 to 150,000, a glass transition temperature of 80° C. or less, and a softening point of less than 100° C.; (c) the colorant comprises a pigment colorant or a dye colorant; (d) the color composition further comprises at least one selected from a surfactant, a dispersant, a defoaming agent, an organic solvent and talc; (e) The thickness of the color layer is 0.5 to 10 μm.

4. The hot stamping film for vehicle license plate according to claim 1 or 2, It is characterized in that The adhesive layer meets one or more of the following conditions: (i) the adhesive layer is formed of an adhesive layer composition, wherein the adhesive layer composition comprises at least one selected from an adhesive, an organic solvent, a resin and a colorant; (ii) the adhesive comprises a thermoplastic acrylic, The thermoplastic acrylic acid has a weight average molecular weight of 1,000 to 100,000, a glass transition temperature of 80° C. or less, a softening point of greater than 100° C., a hydroxyl value of 7 to 13 mgKOH / g, and an acid value of 17 to 23 mgKOH / g; (iii) the organic solvent comprises ethyl acetate; (iv) the resin comprises a non-crystalline polyester and / or a vinyl chloride-vinyl acetate copolymer, The non-crystalline polyester has a weight average molecular weight of 10,000 to 100,000, a glass transition temperature of 30° C. or less, a hydroxyl value of 5 to 11 mgKOH / g, and an acid value of less than 2 mgKOH / g; (v) The thickness of the adhesive layer is 0.5 to 10 μm.

5. A method for manufacturing the hot stamping film for vehicle license plates according to any one of claims 1 to 4, It is characterized in that The manufacturing method comprises: Step A: coating a color composition on a substrate layer and drying to form a color layer; Step B: coating the adhesive layer composition on the color layer and drying to form an adhesive layer.

6. The manufacturing method according to claim 5, It is characterized in that In the step A, the drying temperature is 60 to 120° C. and the drying time is 0.5 to 5 min; In the above step B, the drying temperature is 60 to 120° C., and the drying time is 0.5 to 5 min.

7. The manufacturing method according to claim 5 or 6, It is characterized in that The color composition comprises at least one selected from the group consisting of a resin, a colorant, a surfactant, a dispersant, a defoamer, an organic solvent and talc; The adhesive layer composition comprises at least one selected from the group consisting of an adhesive, an organic solvent, a resin and a colorant.

8. A method for manufacturing a vehicle license plate, wherein include: Hot stamping is performed using the hot stamping film for vehicle number plates according to any one of claims 1 to 4.

9. Use of the hot stamping film for vehicle number plates according to any one of claims 1 to 4 to improve hot stamping adhesion and / or wear resistance in the manufacture of vehicle number plates.

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