Transfer decorated film and method of making same

Abstract

The present application provides a kind of transfer decorative film, including substrate layer 1, texture layer 2, pyrolytic adhesive material layer 32 and varnish layer 4.The varnish layer 4 includes main body resin and high-density resin, and the density of the high-density resin is greater than 1.5g / cm 3 Pyrolytic adhesive material layer, when applied in client, injection molding area is subjected to high temperature and high pressure, and the corresponding area is debonded, which can be easily peeled off from the substrate, while other areas still maintain high adhesion. High-density resin and inorganic filler are added to the formula of varnish layer, the purpose of high-density resin is to sink near the pyrolytic adhesive material layer after film formation, and at the same time, provide lower surface energy, which is convenient for release with pyrolytic adhesive material layer. The inorganic filler can be large-particle-size transparent SiO2, which is to make the surface of varnish layer more smooth, which is convenient for release.

Description

Technical Field

[0001] This invention relates to the field of printing and lamination technology, and more specifically to a transfer decorative film and its preparation method. Background Technology

[0002] In-mold decoration (IMR) technology has gradually replaced various traditional processes due to its technological advantages, becoming a new decorative technology that balances efficiency, cost, and environmental protection. Currently, it is mainly used in 3C products, home appliances, and automotive interior and exterior trim. A typical IMR transfer film structure, from top to bottom, consists of a printing substrate layer, release layer, varnish protective layer, bonding layer, color layer, impact-resistant ink layer, and adhesive layer. The main functions of each layer are as follows: the release layer is used for separation of the part from the substrate during demolding; the varnish layer provides surface protection; the bonding layer enhances the adhesion between the color layer and the varnish layer and can sometimes be omitted; the color layer provides color and appearance; the impact-resistant ink acts as a barrier, protecting the color layer during high-temperature and high-pressure injection molding; and the adhesive layer provides adhesion to the injection-molded particles.

[0003] IMR technology can achieve conventional decorative surfaces with lower costs and higher production efficiency. However, compared with other decorative processes such as IML, INS, and even water transfer printing, IMR's shaping and surface texture capabilities are very limited. This is one of the important reasons why IMR technology cannot further capture more market share. In general, the color of IMR transfer decorative films is provided by the color layer, while the surface texture and gloss are provided by the substrate. Therefore, only certain gloss levels and very shallow brushed or textured surfaces can be achieved. Furthermore, due to the special nature of the IMR process, the brushed or textured surface texture cannot be made too deep; otherwise, excessive local stretching and pressure will cause cracking or other aesthetic defects.

[0004] Currently, typical technical solutions involve creating surface microstructures on the substrate through special brushing or other processing steps. For full-surface gloss adjustments, such as a matte finish, the surface microstructures can also be achieved directly in one step with the substrate. When the substrate is peeled off, the microstructures remain on the surface of the varnish layer, thus achieving the desired brushed pattern or matte surface. It's important to note that this solution offers very limited texture possibilities; it can only achieve partial brushed effects and a fixed gloss level, and cannot realize customized geometric patterns or other designs. Furthermore, the tactile feel it provides is also very weak. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a transfer decorative film and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] One aspect of the present invention provides a transfer decorative film, comprising a substrate layer 1, a texture layer 2, a thermal adhesive layer 32, and a varnish layer 4.

[0008] Furthermore, the varnish layer 4 comprises a base resin and a high-density resin, wherein the high-density resin has a density greater than 1.5 g / cm³. 3 .

[0009] Furthermore, in the varnish layer 4, based on 100 parts by weight of the main resin, the high-density resin comprises 10 to 20 parts.

[0010] Furthermore, the high-density resin of the varnish layer 4 is selected from at least one of polyvinylidene fluoride and polytetrafluoroethylene; the main resin is selected from at least one of polymethyl methacrylate and polyurethane.

[0011] Furthermore, the varnish layer 4 also includes filler, which is 2 to 8 parts by weight of 100 parts of the main resin.

[0012] Furthermore, the filler in the varnish layer 4 is selected from at least one of silica, alumina, magnesium oxide, calcium carbonate, barium sulfate, talc, soapstone, mica, bentonite, and kaolin. Preferably, the particle size of the filler is 2 to 10 μm.

[0013] Furthermore, within any temperature range above the glass transition temperature and below the resin decomposition temperature, the peel strength between the pyrolytic adhesive layer 32 and the varnish layer is less than 5 N / cm.

[0014] Furthermore, a release layer 31 is provided between the pyrolytic adhesive layer 32 and the texture layer 2.

[0015] Furthermore, the thickness of the pyrolytic adhesive layer 32 is 1–3 μm; the thickness of the varnish layer 4 is 20–50 μm.

[0016] A second aspect of the present invention also provides a method for preparing a transfer decorative film as described in the first aspect, characterized in that it includes the following steps: firstly printing a textured layer 2 with a customized pattern on the surface of a substrate 1, and then sequentially printing a pyrolytic adhesive layer 32 and a varnish layer 4.

[0017] Compared with the prior art, the present invention has the following advantages when applying the technical solution of the present invention:

[0018] (1) Thermally debonded material layer: When the customer applies it, the injection area is subjected to high temperature and high pressure, and the corresponding area debonds and can be easily peeled off from the substrate, while other areas still maintain high adhesion.

[0019] (2) High-density resin and inorganic filler are added to the formulation of the varnish layer. The purpose of the high-density resin is to sink to the vicinity of the thermally descaling material layer after film formation, and at the same time provide a lower surface energy to facilitate separation from the thermally descaling material layer.

[0020] (3) The inorganic filler can be transparent SiO2 with a larger particle size, in order to make the surface of the varnish layer smoother and easier to release. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] In the attached diagram:

[0023] Figure 1 A cross-sectional schematic diagram of a transfer decorative film provided according to an embodiment of the present invention is shown;

[0024] Figure 2 A cross-sectional schematic diagram is shown after the substrate layer 1, texture layer 2 and thermal adhesive layer 32 of the transfer decorative film provided according to an embodiment of the present invention have been peeled off.

[0025] The above figures include the following reference numerals: 1 is the substrate layer; 2 is the texture layer; 31 is the release layer; 32 is the thermal adhesive layer; and 4 is the varnish layer. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0029] Currently, the color of typical IMR transfer decorative films is provided by the color layer, while the surface texture and gloss are provided by the substrate. Therefore, only certain gloss levels and very shallow brushed or textured surfaces can be achieved. Furthermore, due to the specific nature of the IMR process, the brushed or textured surface cannot be made too deep; otherwise, excessive local stretching and pressure will cause cracking or other aesthetic defects. To address this issue, this application provides a transfer decorative film and its preparation method.

[0030] In a typical embodiment of this application, the present invention provides a transfer decorative film, including a substrate layer 1, a texture layer 2, a thermally desiccant layer 32, and a varnish layer 4. When applied to a client, the injection molding area is subjected to high temperature and high pressure, and the thermally desiccant layer 32 in the corresponding area desiccant layer debonds and can be easily peeled off from the substrate layer 1, while other areas still maintain high adhesion.

[0031] In a preferred embodiment, the varnish layer 4 comprises a base resin and a high-density resin, wherein the high-density resin has a density greater than 1.5 g / cm³. 3 The high-density resin can sink to the vicinity of the thermally descalable adhesive layer 32 after film formation, while providing a low surface energy to facilitate release from the thermally descalable adhesive layer 32.

[0032] In client applications, the injection molding area is subjected to high temperature and high pressure, and the corresponding thermal debonding material layer 32 debonds and can be easily peeled off from the substrate layer 1, while other areas still maintain high adhesion.

[0033] In a specific embodiment of this application, the varnish layer 4 comprises 100 parts by weight of the main resin and 10-20 parts by weight of the high-density resin. If the weight of the high-density resin is less than 10 parts, the high-density resin is insufficient, resulting in an insufficient thickness and density of the low surface energy layer. This leads to poor release performance and reduced surface testing durability of the finished product. If the weight of the high-density resin is more than 20 parts, the most direct consequence is increased cost, as the high-density resin is much more expensive than the main resin. Furthermore, the low surface energy of the high-density resin is detrimental to interlayer adhesion; adding too much will affect the subsequent interlayer adhesion.

[0034] To ensure compatibility with the formulation system of the clear coat layer, the high-density resin of the clear coat layer 4 is selected from at least one of polyvinylidene fluoride and polytetrafluoroethylene; the main resin is selected from at least one of polymethyl methacrylate and polyurethane.

[0035] To make the surface of the varnish layer 4 smoother, the varnish layer 4 further includes 2 to 8 parts of the filler, which is selected from at least one of silicon dioxide, aluminum oxide, magnesium oxide, calcium carbonate, barium sulfate, talc, soapstone powder, mica powder, bentonite, and kaolin.

[0036] In a preferred embodiment of this application, the particle size of the filler is 2–10 μm. If the particle size of the filler is less than 2 μm, it is too low and will not effectively increase slippage and facilitate peeling. Furthermore, the amount added should not be too high, as this can easily cause the film to become white and foggy. If the particle size of the filler is greater than 10 μm, it can also easily cause the film to become white and foggy.

[0037] In a preferred embodiment of this application, the light transmittance of the filler is >95%; otherwise, it will appear severely white and foggy, affecting the appearance.

[0038] In a specific embodiment of this application, the peel strength between the pyrolytic adhesive layer 32 and the varnish layer is less than 5 N / cm in any temperature range above the glass transition temperature and below the resin decomposition temperature.

[0039] In a specific embodiment of this application, a release layer 31 is provided between the pyrolytic adhesive layer 32 and the texture layer 2. The release layer 31 is a common release layer, which is intended to work with the texture layer to meet the stable peeling force required for demolding during the IMR process.

[0040] In a specific embodiment of this application, to verify the ease of peeling between the pyrolytic adhesive layer and the varnish layer of the transfer decorative film, the adhesive tape peel strength test was performed on the obtained transfer decorative film according to GB / T2792-2014. During room temperature storage and transportation, a certain interlayer adhesion must be maintained to prevent problems such as coating peeling. Therefore, under room temperature storage conditions, the peel strength between the pyrolytic adhesive layer and the varnish layer is less than 30 N / cm. The substrate layer 1, texture layer 2, and most of the pyrolytic adhesive layer 32 will be peeled off, leaving microstructures on the product surface, achieving the desired design and surface feel.

[0041] In a specific embodiment of this application, the thickness of the pyrolytic adhesive layer 32 is 1 to 3 μm, which can satisfy the requirement of uniform coating without defects; the thickness of the varnish layer 4 is 20 to 50 μm.

[0042] In a specific embodiment of this application, the texture layer 2 and the substrate layer 1 can be peeled off from the varnish layer 4, and after the texture layer 2 and the thermally disintegrating adhesive layer 32 are peeled off, an uneven feel is formed on the surface of the varnish layer.

[0043] Specifically, the material of the substrate layer 1 is selected from BOPP, BOPET, NY, and PVC; BOPET is preferred. The above-mentioned substrate has good stiffness and good transparency.

[0044] In a preferred embodiment of this application, the thickness of the substrate layer 1 is 30–100 μm.

[0045] In some specific embodiments of the present invention, the texture layer 2 is a two-component ink. The texture layer 2 is printed onto the substrate surface by a customized gravure printing roller or screen printing plate using a special ink formula. The ink formula is as follows: 33-38% methyl ethyl ketone, 2-7% butyl acetate, 35% modified hydroxy acrylic acid, 0-15% matte powder, 5-10% amino resin, 2-5% acid catalyst, 2-5% slip agent, and 0-2% other additives.

[0046] In some specific embodiments of the present invention, the main functions of each formulation component are as follows: Butanone and butyl acetate are solvents, including but not limited to the above two. The proportion of solvent added mainly depends on the on-site application viscosity and printing quality, while also considering the equipment drying capacity and film drying requirements; Modified hydroxy acrylic acid provides adhesion and key properties, requiring the addition of amino resin and acid catalyst to enhance film strength and interlayer adhesion. The amino resin and acid catalyst need to be added before formal application to ensure sufficient ink opening time. The amount of amino resin and acid catalyst needs to be carefully adjusted according to specific cases; Matte powder is mainly used to provide a customized gloss surface. Without addition, a high-gloss surface of 90-100 GU or higher can be achieved. Adding up to 15% can achieve an ultra-matte surface of 3 GU. The specific amount added needs to be adjusted according to the surface gloss designed by the customer; Slip agent is mainly used to reduce the adhesion between the texture layer and the subsequent release layer and varnish layer; Other additives mainly refer to commonly used additives used to adjust the printing film surface, ink leveling, and bubble performance.

[0047] The texture layer 2 can provide a customized gloss surface, achieving a surface design with a gloss range of 5GU to 100GU according to customer needs. At the same time, combined with different gloss substrates, it can achieve differentiated designs with different gloss levels in different areas.

[0048] In a specific embodiment of this application, the texture layer 2 further includes other additives, which are conventional additives in the art, such as leveling agents and defoamers. The addition of additives mainly addresses the problem of air bubbles in the ink, the leveling effect of the printed film, and the wetting effect between the ink and the substrate; the selected additives play an important role in the final printed appearance. The leveling agent is selected from at least one of ethanol, isopropanol, modified polysiloxane, or unmodified polysiloxane. In ink preparation, avoiding surface defects caused by air bubbles facilitates ink leveling on the substrate surface. This wetting agent can improve the wetting ability of the texture layer ink on the surface of BOPP, BOPET, or BOPA, enhance the adhesion between the texture layer and BOPP, BOPET, or BOPA, and also make the coating surface smoother and denser. The defoamer is selected from at least one of polydimethylsiloxane, ethanol, and polyoxypropylene glycerol ether. The defoamer used in this invention can eliminate small air bubbles formed by high-speed stirring and cross-linking reactions, eliminating the influence of air bubbles on the coating appearance.

[0049] In specific embodiments of this application, the texture layer 2 is generated using one or more of the following processes: screen printing, gravure printing, flexographic printing, or vacuum coating.

[0050] Secondly, this application provides a method for preparing a transfer decorative film, including the following steps: firstly, a textured layer 2 with a customized pattern is printed on the surface of a substrate 1, and then a pyrolytic adhesive layer 32 and a varnish layer 4 are printed sequentially.

[0051] Specifically, the textured layer is dried and cured; preferably, the drying parameters for the textured layer are 140–180°C for 30–120 seconds. The temperature should not exceed 180°C to avoid deformation of the pre-coated film.

[0052] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0053] Example 1

[0054] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of the main resin polymethyl methacrylate (density 1.15 g / cm³). 3 ) and 15 parts by weight of high-density polyvinylidene fluoride resin, wherein the density of the high-density resin is 1.78 g / cm³. 3 .

[0055] Example 2

[0056] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of the main resin polymethyl methacrylate (density 1.15 g / cm³). 3 ) and 20 parts by weight of high-density polyvinylidene fluoride resin, wherein the density of the high-density resin is 1.78 g / cm³. 3 .

[0057] Example 3

[0058] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of the main resin polymethyl methacrylate (density 1.15 g / cm³). 3 ) and 10 parts by weight of high-density polyvinylidene fluoride resin, wherein the density of the high-density resin is 1.78 g / cm³. 3 .

[0059] Example 4

[0060] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of the main resin polymethyl methacrylate (density 1.15 g / cm³). 3 ) and 15 parts by weight of high-density polytetrafluoroethylene resin, wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0061] Example 5

[0062] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 15 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0063] Example 6

[0064] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³.3 .

[0065] Example 7

[0066] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0067] Example 8

[0068] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size 2 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0069] Example 9

[0070] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size 10 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0071] Example 10

[0072] A transfer decorative film includes a substrate layer 1, a textured layer 2, a thermally disintegrating adhesive layer 32 (1 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0073] Example 11

[0074] A transfer decorative film includes a substrate layer 1, a textured layer 2, a thermally disintegrating adhesive layer 32 (3 μm thick), and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0075] Example 12

[0076] A transfer decorative film includes a substrate layer 1, a textured layer 2, a thermally adhesive layer 32 (2 μm thick), a release layer 31, and a varnish layer 4. The varnish layer 4 comprises, by weight, 100 parts by weight of a main resin polyurethane (density 1.1 g / cm³). 3 The mixture comprises 18 parts by weight of high-density polytetrafluoroethylene resin and 6 parts by weight of silica (particle size of 5 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0077] Example 13

[0078] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of the main resin polymethyl methacrylate and 15 parts by weight of high-density polyethylene, wherein the high-density polyethylene has a density of 0.96 g / cm³. 3 .

[0079] Example 14

[0080] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of the main resin polymethyl methacrylate and 7 parts by weight of the high-density resin polyvinylidene fluoride, wherein the high-density resin has a density of 1.78 g / cm³. 3 .

[0081] Example 15

[0082] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of the main resin polymethyl methacrylate and 24 parts by weight of the high-density resin polyvinylidene fluoride, wherein the high-density resin has a density of 1.78 g / cm³. 3 .

[0083] Example 16

[0084] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of a main resin polyurethane, 18 parts by weight of a high-density resin polytetrafluoroethylene, and 6 parts by weight of silica (1 μm particle size), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0085] Example 17

[0086] A transfer decorative film includes a substrate layer 1, a texture layer 2, a thermally disintegrating adhesive layer 32 (2 μm thick), and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of a main resin polyurethane, 18 parts by weight of a high-density resin polytetrafluoroethylene, and 6 parts by weight of silica (12 μm particle size), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0087] Comparative Example 1

[0088] A transfer decorative film includes a substrate layer 1, a texture layer 2, and a varnish layer 4. By weight, the varnish layer 4 comprises 100 parts by weight of a main resin polyurethane, 18 parts by weight of a high-density resin polytetrafluoroethylene, and 6 parts by weight of silica (particle size 12 μm), wherein the density of the high-density resin is 2.3 g / cm³. 3 .

[0089] Performance testing

[0090] The transfer decorative films obtained through Examples 1-17 and Comparative Example 1 were evaluated using the following test methods.

[0091] (1) Peel strength: The peel strength between the pyrolytic adhesive layer 32 and the varnish layer in Examples 1-17 was tested in any temperature range above the glass transition temperature and below the resin decomposition temperature, according to GB / T 2792-2014. The peel between the varnish layer and the texture layer in Comparative Example 1 was observed.

[0092] (2) Gloss: The gloss at a 60° angle was tested according to the standard method of GB / T 8807.

[0093] The specific test results of Examples 1-17 and Comparative Example 1 are shown in Table 1:

[0094] Table 1

[0095]

[0096]

[0097] The test results above show that: Comparative Example 1 does not contain a thermally descaling adhesive layer, and the textured layer and the varnish layer are completely inseparable. All embodiments include a thermally descaling adhesive layer. During client application, the injection molding area is subjected to high temperature and pressure, causing descaling in the corresponding area, allowing easy separation from the substrate, while other areas maintain high adhesion. The varnish layer formulation includes high-density resin and inorganic fillers. The purpose of the high-density resin is to sink to the vicinity of the thermally descaling adhesive layer after film formation, while providing a lower surface energy for easy release from the thermally descaling adhesive layer. The inorganic filler can be transparent SiO2 with a larger particle size, designed to make the surface of the varnish layer smoother and easier to release. In the embodiments of this application, the light transmittance of the filler is 95%; otherwise, whitening is more severe than fogging, affecting the appearance. If the weight percentage of high-density resin is less than 10 parts, insufficient high-density resin results in insufficient thickness and density of the low surface energy layer, leading to poorer release performance and reduced surface test durability of the finished product. If the weight percentage of high-density resin exceeds 20 parts, the most direct consequence is increased cost, as the high-density resin is much more expensive than the main resin. Secondly, the low surface energy of high-density resin is not conducive to interlayer adhesion, and adding too much will affect the subsequent interlayer adhesion.

[0098] The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A transfer decorative film, characterized in that, The coating comprises a substrate layer (1), a texture layer (2), a thermally degradable adhesive layer (32), and a varnish layer (4). The varnish layer (4) comprises a base resin and a high-density resin, wherein the density of the high-density resin is greater than 1.5 g / cm3. The high-density resin in the varnish layer (4) is 10 to 20 parts by weight of the base resin. The high-density resin in the varnish layer (4) is selected from at least one of polyvinylidene fluoride and polytetrafluoroethylene. The base resin is selected from at least one of polymethyl methacrylate and polyurethane. The thermally degradable adhesive layer (32) has a peel strength of less than 5 N / cm from the varnish layer in any temperature range above the glass transition temperature and below the resin decomposition temperature.

2. The transfer decorative film according to claim 1, characterized in that, The varnish layer (4) also includes filler, which is 2 to 8 parts by weight of 100 parts of the main resin.

3. The transfer decorative film according to claim 2, characterized in that, The filler in the varnish layer (4) is selected from at least one of silica, alumina, magnesium oxide, calcium carbonate, barium sulfate, talc, soapstone, mica, bentonite, and kaolin, and the particle size of the filler is 2~10 μm.

4. The transfer decorative film according to claim 1, characterized in that, A release layer (31) is also provided between the pyrolytic adhesive material layer (32) and the texture layer (2).

5. The transfer decorative film according to claim 1, characterized in that, The thickness of the pyrolytic adhesive layer (32) is 1~3μm; the thickness of the varnish layer (4) is 20~50μm.

6. The transfer decorative film according to any one of claims 1 to 5, characterized in that, The process includes the following steps: first, a textured layer (2) with a customized pattern is printed on the surface of the substrate (1), and then a pyrolytic adhesive layer (32) and a varnish layer (4) are printed in sequence.

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