A thermal sublimation retransfer film for metal substrates

Abstract

The present invention relates to the field of thermal transfer technology, and in particular to a thermal sublimation retransfer film for metal substrates. The thermal sublimation retransfer film comprises a substrate, a release layer and a dye receiving layer; the components of the dye receiving layer include a dye receiving resin and a bonding resin; the dye receiving resin is one of a carboxyl type binary copolymer chlorovinyl resin, a carboxyl type ternary copolymer chlorovinyl resin, a chloro-acid resin, an acrylonitrile-styrene copolymer, and a PVP resin; and the bonding resin is one of a polyester, an epoxy modified acrylic resin, and a polyurethane. The thermal sublimation retransfer film can ensure high color concentration when used for thermal sublimation soft label printing, and can also directly thermally transfer patterns to the surface of an untreated metal substrate.

Description

Technical Field

[0001] The invention relates to the technical field of thermal transfer, in particular to a thermal sublimation retransfer film for metal substrates. Background Art

[0002] Thermal transfer film is a special printing film that has a pattern pre-printed on the surface of a PET film. Under the combined action of heat and pressure, the pattern is transferred and attached to the surface of the substrate. It is often used to replace screen printing technology because it can achieve a perfect transition of colors.

[0003] At present, there is no retransfer film on the market that can be directly transferred to metal substrates after thermal sublimation printing. The main reasons are the following: 1. Thermal sublimation ribbon image printing requires a special dye receiving coating, otherwise the dye acceptance is poor and the color concentration is very low. 2. The surface of the substrate is complicated, and a layer of coating must be pre-heat-transferred to improve the adhesion of the substrate surface before the thermal transfer of the pattern can be achieved. Therefore, this method has the defects of a relatively cumbersome operation process and high cost. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a thermal sublimation retransfer film for metal substrates.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] The present invention provides a thermal sublimation retransfer film for metal substrates, comprising a substrate, a release layer arranged on the substrate, and a dye receiving layer arranged on the release layer;

[0007] The components of the dye receiving layer include a dye receiving resin and a bonding resin;

[0008] The dye receiving resin is one of carboxyl binary copolymer chlorovinyl resin, carboxyl ternary copolymer chlorovinyl resin, chloroform resin, acrylonitrile-styrene copolymer, and PVP resin; the bonding resin is one of polyester, epoxy modified acrylic resin, and polyurethane.

[0009] Furthermore, the dye receiving resin is a carboxyl type ternary copolymer chlorovinyl resin; the bonding resin is polyester; the mass fraction of the carboxyl type ternary copolymer chlorovinyl resin is 19 parts, and the mass fraction of the polyester is 2-5 parts.

[0010] Furthermore, in the carboxyl-type ternary copolymer chlorovinyl resin, the molar mass ratio of vinyl chloride monomer to vinyl acetate monomer is in the range of 80:20-90:10.

[0011] Furthermore, the dye receiving layer also includes an adhesion promoter, a liquid lubricant and an organic solvent; in the dye receiving layer, the adhesion promoter has a mass fraction of 1 to 3 parts, the liquid lubricant has a mass fraction of 1 to 5 parts, and the first organic solvent has a mass fraction of 50 to 80 parts.

[0012] Furthermore, the adhesion promoter is a resin adhesion promoter, a silane coupling agent adhesion promoter or a titanate coupling agent adhesion promoter.

[0013] Further, the release layer comprises an adhesive resin and a bonding resin;

[0014] The attachment resin is one of vinyl chloride-vinyl acetate copolymer, acrylic resin, chlorinated resin, highly chlorinated polyethylene resin, chlorinated polyvinyl chloride resin, and chlorinated polyethylene resin; the bonding resin is one of polyurethane resin, polyester resin, and polycarbonate resin.

[0015] Furthermore, the attachment resin is a vinyl chloride-vinyl acetate copolymer; the bonding resin is a polyurethane resin; the mass fraction of the vinyl chloride-vinyl acetate copolymer is 10-80 parts, and the mass fraction of the polyurethane resin is 2-5 parts.

[0016] Furthermore, the release layer also includes an anti-hydrolysis agent and a second organic solvent; the mass fraction of the anti-hydrolysis agent is 1 part to 5 parts, and the mass fraction of the second organic solvent is 50 parts to 80 parts.

[0017] Furthermore, the thickness of the dye receiving layer is 5-15 μm, and the thickness of the release layer is 1-5 μm.

[0018] Furthermore, the material of the substrate is PET; the thickness of the substrate 1 is 20-125 μm, and the weight is 30-100 g / m 2 .

[0019] The beneficial effects of the present invention are:

[0020] (1) In the thermal sublimation retransfer film for metal substrates of the present invention, the dye receiving resin is one of carboxyl type binary copolymer chlorovinyl acetate resin, carboxyl type ternary copolymer chlorovinyl acetate resin, chloroform resin, acrylonitrile-styrene copolymer, and PVP resin, wherein the carboxyl type binary copolymer chlorovinyl acetate resin and the carboxyl type ternary copolymer chlorovinyl acetate resin are particularly preferred, which can improve the adhesion of the dye on the surface of the metal substrate after being transferred to the metal substrate;

[0021] (2) The thermal sublimation retransfer film for metal substrates of the present invention can ensure that the dye receiving layer can well receive the dye and has good interlayer adhesion with the release layer by using a dye receiving resin and a bonding resin as components of the dye receiving layer;

[0022] (3) The thermal sublimation retransfer film for metal substrates of the present invention ensures that the dye receiving layer will not peel off from the substrate under high-speed printing by using an adhesive resin and an adhesive resin. At the same time, during thermal transfer, the dye receiving layer is helped to be smoothly separated from the substrate to the surface of the metal substrate;

[0023] (4) The thermal sublimation retransfer film for metal substrates of the present invention can ensure high color concentration while being used for thermal sublimation soft label printing, and can also directly thermally transfer patterns to the surface of untreated metal substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the structure of each layer of the thermal sublimation retransfer film for metal substrates of the present invention.

[0025] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0026] 1. Substrate; 2. Release layer; 3. Dye receiving layer. DETAILED DESCRIPTION

[0027] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0028] like Figure 1 As shown, the thermal sublimation retransfer film for metal substrates of the present invention comprises a substrate 1, a release layer 2 arranged on the substrate 1, and a dye receiving layer 3 arranged on the release layer 2; the components of the dye receiving layer 3 include a dye receiving resin and a bonding resin; wherein the dye receiving resin is one of a carboxyl type binary copolymer chlorovinyl resin, a carboxyl type ternary copolymer chlorovinyl resin, a chloroform resin, an acrylonitrile-styrene copolymer, and a PVP resin; and the bonding resin is one of a polyester, an epoxy-modified acrylic resin, and a polyurethane.

[0029] The thermal sublimation retransfer film of the present invention can improve the adhesion of the dye on the surface of the metal substrate after being transferred to the metal substrate by using a dye receiving resin and a bonding resin as components of the dye receiving layer 3. It can also ensure that the dye receiving layer 3 can well receive the dye and has good interlayer adhesion with the release layer 2.

[0030] The thermal sublimation retransfer film of the present invention is particularly suitable for soft label printing.

[0031] The dye receiving layer 3 of the present invention mainly functions to receive the dye during the thermal sublimation ribbon image printing process, and has good coloring ability, and has better interlayer adhesion with the release layer 2, and is not easy to peel off.

[0032] Preferably, the dye receiving resin is a carboxyl-type ternary copolymer chloroacetic acid resin, in which the molar mass ratio of vinyl chloride monomer to vinyl acetate monomer is in the range of 80:20-90:10; in the carboxyl-type ternary copolymer chloroacetic acid resin, the ternary chloroacetic acid contains polar groups, and the hydroxyl or carboxyl type can coordinate with the metal to form a chemical bond, thereby increasing the adhesion between the dye receiving layer 3 and the metal substrate; therefore, the dye receiving layer 3 of the present invention is more suitable for metal substrates than other materials such as glass substrates.

[0033] Preferably, the bonding resin is polyester; polyester can exhibit excellent bonding properties, and has excellent flexibility, bendability, applicability, corrosion resistance, durability, heat resistance, and solvent solubility.

[0034] Preferably, the adhesion promoter is a resin adhesion promoter, a silane coupling agent adhesion promoter, a titanate coupling agent adhesion promoter, an organic polymer compound or the like.

[0035] The adhesion promoter can improve the bonding force between the dye receiving layer 3 and the metal substrate and the release layer 2.

[0036] In the heat sublimation printing process, the heat sublimation ribbon contacts the dye receiving layer 3, and by heating, the dye is transferred to the dye receiving layer 3. Heating easily causes the resin component of the dye receiving layer 3 to melt and produce the problem of bonding, and the problem of the dye receiving layer 3 anti-sticking ribbon may also occur when printing patterns. Therefore, a lubricant is added to the dye receiving layer 3 of the present invention, and a solid or liquid lubricant can be selected.

[0037] Preferably, liquid silicone oil is used as the lubricant. In order not to affect the adhesion of the retransfer film of the present invention on the metal substrate, epoxy-modified organic siloxane is further preferably used as the lubricant, or silicone oil with reactive groups is cross-linked and cured with epoxy resin.

[0038] Generally, there is no particular limitation on the first organic solvent of the dye receiving layer 3, as long as the resin component can be dissolved in a suitable organic solvent and the viscosity at 25° C. is within 100-500 mPa·s. For example, the first organic solvent may be acetone, 2-butanone, cyclohexanone, ethyl acetate, butyl acetate, propyl acetate, toluene, xylene, DMF, etc.

[0039] Further preferably, the first organic solvent is a mixed solution of 2-butanone and toluene, and the mass ratio of 2-butanone to toluene is controlled between 8:2 and 1:1.

[0040] Preferably, the components of the dye receiving layer 3 of the present invention are as follows: 19 parts by weight of carboxyl-type ternary copolymer chlorovinyl resin, 2-5 parts by weight of polyester, 1-3 parts by weight of adhesion promoter, 1-5 parts by weight of liquid lubricant, and 50-80 parts by weight of the first organic solvent.

[0041] Preferably, the thickness of the dye receiving layer 3 is 5-15 μm; more preferably, the thickness of the dye receiving layer 3 is 5-10 μm.

[0042] The release layer 2 of the present invention mainly functions to impart a certain adhesion to the dye receiving layer 3 during thermal sublimation printing.

[0043] The release layer 2 of the present invention comprises an attachment resin and an adhesive resin; the attachment resin is one of vinyl chloride-vinyl acetate copolymer, acrylic resin, chlorinated polyethylene resin, chlorinated polyvinyl chloride resin, and chlorinated polyethylene resin; the adhesive resin is one of polyurethane resin, polyester resin, and polycarbonate resin; it can ensure that the dye receiving layer 3 will not peel off from the substrate 1 under high-speed printing. At the same time, during thermal transfer, it helps the dye receiving layer 3 to be smoothly separated from the substrate 1 to the surface of the metal substrate.

[0044] Preferably, the attachment resin is vinyl chloride-vinyl acetate copolymer; it can make the dye receiving layer 3 adhere well to the substrate 1 and can also ensure smooth peeling during transfer.

[0045] Preferably, in the vinyl chloride-vinyl acetate copolymer, the molar mass ratio of vinyl chloride monomer to vinyl acetate monomer is in the range of 80:20-90:10.

[0046] Preferably, the adhesive resin is polyurethane resin; polyurethane has excellent high tension, high tensile strength, strong toughness and aging resistance, and is a mature environmentally friendly material. It has the characteristics of high strength, good toughness, wear resistance, cold resistance, oil resistance, aging resistance, and weather resistance that other plastic materials cannot match.

[0047] Because the polyurethane resin coating film surface absorbs water and shrinks under high temperature and high humidity environment, it is necessary to add an anti-hydrolysis agent to increase its storage performance.

[0048] Preferably, the weight fraction of the anti-hydrolysis agent is 1-2.5 parts; if the amount of the anti-hydrolysis agent added is too little, the storage property will not be significantly improved, and if too much is added, the cost will be too high and the anti-hydrolysis performance will not be significantly improved.

[0049] There is no particular limitation on the type of the second organic solvent, as long as the resin component of the release layer 2 can be dissolved in a suitable organic solvent and the viscosity at 25° C. is within 100-500 mPa·s. For example, the organic solvent may be acetone, 2-butanone, cyclohexanone, ethyl acetate, butyl acetate, propyl acetate, toluene, xylene, DMF, etc. The mass fraction of the second organic solvent is 50-80 parts.

[0050] Preferably, the second organic solvent is a mixed solution of 2-butanone and toluene, and the ratio of 2-butanone to toluene is controlled between 8:2 and 1:1.

[0051] Preferably, the thickness of the release layer 2 is 1-5 μm; more preferably, the thickness of the release layer 2 is 1-3 μm.

[0052] The material of the substrate 1 of the present invention is PET, which is a common material used for packaging printing on the market.

[0053] Preferably, the thickness of the substrate 1 is 20-125 μm, and the weight is 30-100 g / m 2 .

[0054] The technical solution of the present invention is illustrated by means of specific embodiments below:

[0055] Embodiment 1:

[0056] The retransfer film of this embodiment has a base 1 with a thickness of 50 μm and a weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0057] The specific components and weight percentages of release layer 2 are: 19 parts of dichlorovinyl resin (SOLBIN-C Nissin Chemical), 2 parts of polyurethane (R-6835 Hunan Jinliyuan), 0.5 parts of anti-hydrolysis stabilizer (S-7000 Beijing Baiyuan Chemical), 39.25 parts of 2-butanone, and 39.25 parts of toluene. The coating is applied by a gravure coater, and the coating thickness is 2 μm.

[0058] The specific components and mass fractions of the dye receiving layer 3 are: polyester (670 Japan Toyobo) 10 parts, carboxyl type ternary copolymer chlorovinyl resin (SOLBIN-M5 Nissin Chemical) 15 parts, polyurethane (R-6835 Hunan Jinliyuan) 5 parts, adhesion promoter (Addbond 2325 Digao Chemical) 1 part, epoxy modified silicone oil (KF-105 Shin-Etsu silicone) 0.5 parts, 2-butanone 34.25 parts, toluene 34.25 parts. Use a gravure coater to coat, the coating thickness is 8 μm.

[0059] Example 2

[0060] The retransfer film of this embodiment has a base 1 with a thickness of 50 μm and a weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0061] The specific components and weight fractions of release layer 2 are: 19 parts of dichlorovinyl resin (H15 / 42 Wacker, Germany), 2 parts of polyurethane (TPU-5778 Lubrizol), 1.5 parts of anti-hydrolysis stabilizer (S-7000, Beijing Baiyuan Chemical), 38.75 parts of 2-butanone, and 38.75 parts of toluene. The coating is applied using a gravure coater, and the coating thickness is 2 μm.

[0062] The scheme of the dye receiving layer 3 is the same as that of Example 1.

[0063] Example 3

[0064] The retransfer film of this embodiment has a base 1 with a thickness of 50 μm and a weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0065] The scheme of release layer 2 is consistent with that of embodiment 1.

[0066] The specific components and mass fractions of the dye receiving layer 3 are: 20 parts of ternary chloroacetic acid resin (H15 / 45M German Wacker), 5 parts of acrylic modified epoxy resin (A-102 Xieyu New Materials), 1 part of polyisocyanate curing agent (MHG-80B Asahi Chemical Multi-Nite), 0.3 parts of plasticizer (A110 Maoheng Chemical), 0.5 parts of epoxy modified silicone oil (KF-105 Shin-Etsu Silicone), 36.6 parts of 2-butanone, and 36.6 parts of toluene. The coating was applied using a gravure coater, and the coating thickness was 8 μm.

[0067] Example 4

[0068] The retransfer film of this embodiment has a base 1 with a thickness of 50 μm and a weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0069] The scheme of release layer 2 is consistent with that of embodiment 2.

[0070] The specific components and mass fractions of the dye receiving layer 3 are: polyester (670 Japan Toyobo) 15 parts, vinyl chloride-vinyl acetate copolymer (CP450 Korea Hanhua) 15 parts, polyurethane (901H Wanhua Chemical) 5 parts, adhesion promoter (Addbond2325 Di Gao Chemical) 1 part, epoxy modified silicone oil (KF-105 Shin-Etsu Silicone) 0.5 parts, 2-butanone 31.75 parts, toluene 31.75 parts. Use a gravure coater to coat, the coating thickness is 8 μm.

[0071] Example 5

[0072] The retransfer film of this embodiment has a base 1 with a thickness of 50 μm and a weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0073] The scheme of release layer 2 is consistent with that of Example 1.

[0074] The specific components and mass fractions of the dye receiving layer 3 are: 15 parts of carboxyl type ternary copolymer chlorovinyl resin (SOLBIN-M5 Nissin Chemical), 6 parts of epoxy modified acrylic resin (SWA 5101 Kunshan Sanwang Resin Co., Ltd.), 5 parts of polyurethane (901H Wanhua Chemical), 1 part of adhesion promoter (LTH Digao Chemical), 0.3 parts of polyethylene wax (BYK-991 German Bick), 0.3 parts of dispersant (BYK-163 German Bick), 36.2 parts of 2-butanone, and 36.2 parts of toluene. The coating was applied using a gravure coater, and the coating thickness was 8 μm.

[0075] Comparative Example 1

[0076] The retransfer film of this comparative example has a substrate 1 with a thickness of 50 μm and a gram weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0077] There is no release layer 2 and dye receiving layer 3.

[0078] Comparative Example 2

[0079] The retransfer film of this comparative example 1 has a substrate 1 with a thickness of 50 μm and a gram weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0080] The release layer 2 is consistent with that in Example 1, but without the dye receiving layer 3.

[0081] Comparative Example 3

[0082] The retransfer film of this comparative example 1 has a substrate 1 with a thickness of 50 μm and a gram weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0083] The specific components and weight fractions of the release layer 2 are: 19 parts of vinyl chloride-vinyl acetate copolymer (MLC-14-55 Pangao Chemical), 40.5 parts of 2-butanone, and 40.5 parts of toluene. The release layer 2 is coated using a gravure coater, and the coating thickness is 2 μm.

[0084] The dye receiving layer 3 is the same as that of Example 1.

[0085] Comparative Example 4

[0086] The retransfer film of this comparative example 1 has a substrate 1 with a thickness of 50 μm and a gram weight of 35 g / m 2PET film, the manufacturer is Guangdong Shunming Products.

[0087] The release layer 2 is consistent with that in Example 1.

[0088] The specific components and weight percentages of the dye receiving layer 3 are: 20 parts of tertiary chloroacetic acid (H15 / 45M Wacker, Germany), 0.3 parts of plasticizer (A110 Maoheng Chemical), 0.5 parts of epoxy modified silicone oil (KF-105 Shin-Etsu Silicone), 39.6 parts of 2-butanone, and 39.6 parts of toluene. The coating was applied using a gravure coater, and the coating thickness was 8 μm.

[0089] Comparative Example 5

[0090] The retransfer film of this comparative example 1 has a substrate 1 with a thickness of 50 μm and a gram weight of 35 g / m 2 PET film, the manufacturer is Guangdong Shunming Products.

[0091] The specific components and weight fractions of release layer 2 are: 20 parts of polyurethane (R-6835 Hunan Jinliyuan), 0.5 parts of anti-hydrolysis stabilizer (S-7000 Beijing Baiyuan Chemical), 39.75 parts of 2-butanone, and 39.75 parts of toluene. The coating is applied using a gravure coater, and the coating thickness is 2 μm.

[0092] The dye receiving layer 3 is the same as that of Example 1.

[0093] The retransfer films of the above-mentioned embodiments and comparative examples were subjected to performance tests. The specific performance test scheme is as follows. The test results are shown in Tables 1 and 2.

[0094] The printing test was conducted using a DNP DS620 thermal sublimation printer, the original DNP DS620 ribbon was used, and the coated retransfer film was used for printing test. The color density test pattern was a 255 grayscale image, the color uniformity test pattern was a 150 grayscale image, and the print sample size was 6×6 inches. The color density was tested using an X-Rite i1-PRO3 colorimeter, and the color density was taken as the average of 256 points. The transfer was performed by hot pressing the metal substrate surface at a high temperature of 140-180°C.

[0095] The adhesion test uses the German BYK-white grid knife test, and the grade refers to the ISO 2409 cross-cut test standard, as shown below:

[0096] 0: The cutting edge is completely smooth; no grid is missing.

[0097] 1: A small amount of coating falls off at the intersection of the cuts. The cross-cut area affected cannot be greater than 5%.

[0098] 2: Coating is peeling off at the cut edges and / or intersections. The affected cut area is greater than 5% but less than 15%.

[0099] 3: The coating has partially or completely fallen off in large pieces along the cut edge and / or partially or completely fallen off in different parts of the grid. The affected cut area is greater than 15% but less than 35%.

[0100] 4: Coating is falling off in large pieces along the cut edge and / or some cells are partially or completely falling off. The affected cut area is greater than 35% but less than 65%.

[0101] 5: Any degree of shedding beyond Level 4.

[0102] The friction resistance test refers to GB17497.1-2012.

[0103] The MCJ-01A friction tester independently developed and produced by Jinan Languang Electromechanical Technology Co., Ltd. was used to test the wear resistance of the samples. The friction pressure was 20±0.2N, the friction speed was 43 times / min, and the number of frictions was 40 times. The wear resistance of the samples was determined by visual inspection, and the judgment criteria are as follows:

[0104] √: The ink layer on the printed surface does not show through (fade) or stain the paper surface due to friction;

[0105] ×: The ink layer on the printed surface is exposed (fading) or the paper surface is stained due to friction.

[0106] The solvent resistance friction test standard is as follows:

[0107] Tie white cotton gauze to the bottom of the tool with a 1.0kg weight, dip it in 95% alcohol, and then use the white cotton gauze to move back and forth 300 times on the printed pattern. Use the X-Rite i1-PRO3 colorimeter to test the optical density before and after solvent friction, and calculate the ratio of optical density after test / optical density before test. The judgment criteria are as follows:

[0108] √: Optical density after test / optical density before test ≥ 0.8;

[0109] ×: optical density after test / optical density before test < 0.8;

[0110] ※Optical density-the light density absorbed by the object being tested.

[0111] Table 1 Performance test results of Examples 1-5

[0112]

[0113] Table 2 Performance test results of comparative examples 1-5

[0114]

[0115] It can be seen from the above test results that the various properties of Examples 1-5 are significantly better than those of Comparative Examples 1-5.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermal sublimation retransfer film for metal substrates, comprising a substrate (1), a release layer (2) arranged on the substrate (1), and a dye receiving layer (3) arranged on the release layer (2); characterized in that: The dye receiving layer (3) comprises a dye receiving resin and a bonding resin; The dye receiving resin is a carboxyl type ternary copolymer chlorovinyl resin; the bonding resin is polyester; the mass fraction of the carboxyl type ternary copolymer chlorovinyl resin is 19 parts, and the mass fraction of the polyester is 2-5 parts; In the carboxyl type ternary copolymer chlorovinyl resin, the molar mass ratio of vinyl chloride monomer to vinyl acetate monomer is in the range of 80:20-90:10; The dye receiving layer (3) further comprises an adhesion promoter, a liquid lubricant and a first organic solvent; in the dye receiving layer (3), the adhesion promoter comprises 1 to 3 parts, the liquid lubricant comprises 1 to 5 parts, and the first organic solvent comprises 50 to 80 parts by weight; The release layer (2) comprises an adhesive resin and an adhesive resin; The attachment resin is a vinyl chloride-vinyl acetate copolymer; the bonding resin is a polyurethane resin; the mass fraction of the vinyl chloride-vinyl acetate copolymer is 10 to 80 parts, and the mass fraction of the polyurethane resin is 2 to 5 parts.

2. The thermal sublimation retransfer film for metal substrates according to claim 1, characterized in that: The adhesion promoter is a resin adhesion promoter, a silane coupling agent adhesion promoter or a titanate coupling agent adhesion promoter.

3. The thermal sublimation retransfer film for metal substrates according to claim 1, characterized in that: The release layer (2) further comprises an anti-hydrolysis agent and a second organic solvent. In the release layer (2), the mass fractions of the various components are: the mass fraction of the anti-hydrolysis agent is 1 part to 5 parts, and the mass fraction of the second organic solvent is 50 parts to 80 parts.

4. The thermal sublimation retransfer film for metal substrates according to claim 1, characterized in that: The thickness of the dye receiving layer (3) is 5-15 μm, and the thickness of the release layer (2) is 1-5 μm.

5. The thermal sublimation retransfer film for metal substrates according to claim 1, characterized in that: The material of the substrate (1) is PET; the thickness of the substrate (1) is 20-125 μm, and the weight is 30-100 g / m 2 .

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