Preparation process of UV process heat transfer film

Abstract

The invention relates to the technical field of preparation of heat transfer films, in particular to a preparation process of a UV process heat transfer film, which comprises the following steps: base film selection, base film surface treatment, release agent selection, release agent coating, UV paint coating, bridging agent selection, printing, photocuring and film stripping: stripping the photocured transfer film from the base film to form the final UV heat transfer film. According to the UV heat transfer film prepared by the process, the adhesive force of the pattern layer and the UV coating layer is better, the compactness is higher, the product quality is improved, and the service life of the UV heat transfer film is prolonged; in addition, the efficiency is improved more quickly during curing, the residual adhesive rate is low after demolding and stripping, and the product quality is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal transfer film preparation, and particularly relates to a preparation process of a UV process thermal transfer film. Background Art

[0002] Thermal transfer technology is a non-contact imaging technology that heats the printer's print head to transfer the ink on the thermal transfer ribbon to labels such as coated paper, silver-resistant paper, bright white PET or clothing, food packaging, electronic product packaging and other substrates, thereby obtaining text, images, QR codes and other information pre-set on the computer. It is favored by various fields because it can provide people with the information they need simply and quickly. However, the existing thermal transfer process still has problems such as insufficient adhesion between the printed coating and the UV coating, insufficient density of the coating affecting the appearance, and short service life. At the same time, there is a high rate of residual glue after peeling during demolding, which affects product quality.

[0003] Therefore, the above problems need to be solved urgently. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a preparation process of a UV process thermal transfer film to solve the above-mentioned technical problems.

[0005] Technical solution: In order to achieve the above-mentioned purpose, the present invention provides a preparation process of a UV process thermal transfer film, comprising the following steps: S1, base film selection: polyester film (PET) is selected as the base layer of the transfer film; S2, surface treatment of base film: the base film is treated with a corona method to increase its surface energy; S3, release agent selection: select a quick-drying release agent with excellent performance; S4, release agent coating: Use a coating machine to evenly coat the release agent on the base film to ensure the thickness and uniformity of the release layer.

[0006] S5, UV coating: evenly coating the UV coating on the release layer to form a UV coating layer, ensuring the thickness and uniformity of the coating; S7, bridging agent selection: select modified polyurethane resin as a bridging agent and apply it on the UV coating layer to form a bridging layer.

[0007] S8, printing: using gravure printing or screen printing to print the desired pattern on the bridging layer to form a pattern layer, and drying the printed pattern layer; S8, light curing: Use a UV light curing machine to light cure the coated film to form a stable coating; S9 film stripping: peel off the photocured transfer film from the base film to form the final UV thermal transfer film.

[0008] The principle of corona treatment of base film is to apply high-frequency and high-voltage electricity to the treatment equipment to generate high-frequency and high-voltage discharge, and produce small and dense purple-blue sparks. Various ions generated after air ionization accelerate and impact the plastic film in the treatment device under the action of strong electric field. The chemical bonds of plastic molecules are broken and degraded, increasing surface roughness and surface area. A large amount of ozone is also generated during discharge. Ozone is a strong oxidant that can oxidize plastic molecules and produce carbonyl and peroxide groups with strong polarity, thereby increasing its surface energy. This can improve the adhesion of the base film surface and improve product quality.

[0009] Choose a quick-drying release agent with excellent performance, which has a fast curing and film-forming speed to improve production efficiency.

[0010] A bridging agent is used to enhance the bonding force between the UV coating layer and the pattern layer, and the modified polyurethane resin has high strength, good corrosion resistance, flexibility and excellent bonding properties.

[0011] Further, the ratio of each component of the release agent is: 50-60 parts of fluorine-containing silicone, 10-20 parts of hydrogen-containing silicone oil, 5-10 parts of perfluoroalkylethylene, 30-50 parts of fluorine-containing acrylic monomer, 20-60 parts of alkylvinylpolysiloxane, 0.1-1 parts of catalyst, and 100-300 parts of solvent. By adopting alkylvinylpolysiloxane with a vinyl mass fraction of 0.1-0.5%, the curing film-forming speed of fluorosilicone resin can be increased, and high vinyl content can increase the cross-linking density of the cross-linked network and improve the compactness of the coating. By adopting perfluoroalkylethylene with a carbon number of 6-12, fluorosilicone resin can have a lower surface tension, can maintain a good release state during long-term use, and has a low residual glue rate after peeling. And the formed release film has a uniform color on the film surface, the overall system is stable, and there will be no problems of whitening and particle precipitation.

[0012] Furthermore, the UV coating includes hyperbranched epoxy modified resin: 40-42%, polyester modified acrylic: 17-18%, cellulose resin: 3-4%, TPO photoinitiator: 1-2%, photoinitiator: 2-3%, leveling agent: 0.5-1%, adhesion promoter: 1-2%, wetting agent: 1-0.5%, modified polyurethane resin: 20-22%, butyl ester: 3.5-9.5%, ethyl ester: 3-4%.

[0013] Furthermore, the thickness of the UV coating layer is 7-12 μm.

[0014] Furthermore, the preparation of the UV coating includes: A1, mix the selected raw materials according to the formula ratio, use a high-speed mixer to fully stir to ensure that the components are evenly dispersed. Avoid introducing air during the stirring process to avoid generating bubbles; A2. The stirred paint needs to be filtered to remove impurities and large particles to ensure the purity of the paint, and then the bubbles in the paint need to be removed by a vacuum degassing machine to prevent pinholes and bubbles from appearing on the surface of the coating.

[0015] Furthermore, the fineness of the UV coating is not greater than 8µm.

[0016] Furthermore, the polyester modified acrylic acid is prepared from methyl methacrylate, butyl acrylate, acrylic acid, tricarboxymethyl propane, dicumyl peroxide, neopentyl glycol, adipic acid and a diluent.

[0017] Furthermore, the leveling agent is one or a mixture of polysiloxane leveling agents, acrylic or acrylate leveling agents.

[0018] Furthermore, the light curing temperature is 50-70 degrees, and the curing time is 10-15 seconds.

[0019] Furthermore, the base film surface treatment also includes base film pretreatment, and the base film pretreatment includes improving flatness and surface cleaning. The base film pretreatment can effectively improve its adhesion, improve surface flatness and achieve the purpose of cleaning the surface.

[0020] It can be seen from the above technical solution that the present invention has the following beneficial effects: The UV thermal transfer film produced by this process has better adhesion and higher density between the pattern layer and the UV coating layer, which improves the product quality and its service life. In addition, the efficiency is improved more quickly during curing, and the low residual glue rate after film stripping further improves the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention provides a flow chart of a process for preparing a UV thermal transfer film. DETAILED DESCRIPTION

[0022] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0023] like Figure 1 As shown, a preparation process of a UV process thermal transfer film includes the following steps: S1, base film selection: Choose polyester film (PET) as the base layer of the transfer film; polyester film has good surface flatness and transparency, which can improve the quality and appearance of printed products; S2, surface treatment of base film: the base film is treated with a corona method to increase its surface energy; in addition, the surface treatment of the base film can also be carried out by chemical treatment.

[0024] S3, release agent selection: select a quick-drying release agent with excellent performance; S4, release agent coating: Use a coating machine to evenly coat the release agent on the base film to ensure the thickness and uniformity of the release layer.

[0025] S5, UV coating: evenly coating the UV coating on the release layer to form a UV coating layer, ensuring the thickness and uniformity of the coating; S7, bridging agent selection: select modified polyurethane resin as a bridging agent and apply it on the UV coating layer to form a bridging layer.

[0026] S8, printing: using gravure printing or screen printing to print the desired pattern on the bridging layer to form a pattern layer, and drying the printed pattern layer; S8, light curing: Use a UV light curing machine to light cure the coated film to form a stable coating; S9 film stripping: peel off the photocured transfer film from the base film to form the final UV thermal transfer film.

[0027] As a preferred embodiment, the ratio of the components of the release agent is: 50-60 parts of fluorine-containing silicone, 10-20 parts of hydrogen-containing silicone oil, 5-10 parts of perfluoroalkylethylene, 30-50 parts of fluorine-containing acrylic monomer, 20-60 parts of alkyl vinyl polysiloxane, 0.1-1 parts of catalyst, and 100-300 parts of solvent.

[0028] Among them, the UV coating includes hyperbranched epoxy modified resin: 40-42%, polyester modified acrylic: 17-18%, cellulose resin: 3-4%, TPO photoinitiator: 1-2%, photoinitiator: 2-3%, leveling agent: 0.5-1%, adhesion promoter: 1-2%, wetting agent: 1-0.5%, modified polyurethane resin: 20-22%, butyl ester: 3.5-9.5%, ethyl ester: 3-4%.

[0029] Specifically, the thickness of the UV coating layer is 7-12 μm.

[0030] Wherein, the preparation of the UV coating includes: A1, mix the selected raw materials according to the formula ratio, use a high-speed mixer to fully stir to ensure that the components are evenly dispersed. Avoid introducing air during the stirring process to avoid generating bubbles; A2. The stirred paint needs to be filtered to remove impurities and large particles to ensure the purity of the paint, and then the bubbles in the paint need to be removed by a vacuum degassing machine to prevent pinholes and bubbles from appearing on the surface of the coating.

[0031] Specifically, the fineness of the UV coating is no more than 8µm.

[0032] The polyester modified acrylic acid is prepared from methyl methacrylate, butyl acrylate, acrylic acid, tricarboxymethyl propane, diisopropylbenzene peroxide, neopentyl glycol, adipic acid and a diluent.

[0033] Wherein, the leveling agent is one or a mixture of polysiloxane leveling agent, acrylic or acrylate leveling agent.

[0034] Specifically, the light curing temperature is 50-70 degrees, and the curing time is 10-15 seconds. It should be noted that the light curing parameters are not unique, and need to be specifically customized according to factors such as coating thickness, ultraviolet intensity, added solvent, ambient temperature, etc.

[0035] Preferably, the base film pretreatment is further included before the base film surface treatment, and the base film pretreatment includes improving flatness and surface cleaning.

[0036] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A process for preparing a UV thermal transfer film, characterized in that: The steps include: S1, base film selection: polyester film (PET) is selected as the base layer of the transfer film; S2, surface treatment of base film: the base film is treated with a corona method to increase its surface energy; S3, release agent selection: select a quick-drying release agent with excellent performance; S4, release agent coating: Use a coating machine to evenly coat the release agent on the base film to ensure the thickness and uniformity of the release layer. S5, UV coating: evenly coating the UV coating on the release layer to form a UV coating layer, ensuring the thickness and uniformity of the coating; S7, bridging agent selection: select modified polyurethane resin as a bridging agent and apply it on the UV coating layer to form a bridging layer. S8， Printing: Use gravure printing or screen printing to print the desired pattern on the bridge layer to form a pattern layer, and dry the printed pattern layer; S8, light curing: Use a UV light curing machine to light cure the coated film to form a stable coating; S9 film stripping: peel off the photocured transfer film from the base film to form the final UV thermal transfer film.

2. The preparation process of a UV process thermal transfer film according to claim 1, characterized in that: The ratio of the components of the release agent is: 50-60 parts of fluorine-containing silicone, 10-20 parts of hydrogen-containing silicone oil, 5-10 parts of perfluoroalkylethylene, 30-50 parts of fluorine-containing acrylic monomer, 20-60 parts of alkyl vinyl polysiloxane, 0.1-1 parts of catalyst, and 100-300 parts of solvent.

3. The preparation process of a UV process thermal transfer film according to claim 1, characterized in that: The UV coating comprises 40-42% of hyperbranched epoxy modified resin, 17-18% of polyester modified acrylic acid, 3-4% of cellulose resin, 1-2% of TPO photoinitiator, 2-3% of photoinitiator, 0.5-1% of leveling agent, 1-2% of adhesion promoter, 1-0.5% of wetting agent, 20-22% of modified polyurethane resin, 3.5-9.5% of butyl ester and 3-4% of ethyl ester.

4. The process for preparing a UV thermal transfer film according to claim 1, characterized in that: The thickness of the UV coating layer is 7-12 μm.

5. The preparation process of a UV process thermal transfer film according to claim 1, characterized in that: The preparation of the UV coating comprises: A1, mix the selected raw materials according to the formula ratio, use a high-speed mixer to fully stir to ensure that the components are evenly dispersed. Avoid introducing air during the stirring process to avoid generating bubbles; A2. The stirred paint needs to be filtered to remove impurities and large particles to ensure the purity of the paint, and then the bubbles in the paint need to be removed by a vacuum degassing machine to prevent pinholes and bubbles from appearing on the surface of the coating.

6. The process for preparing a UV thermal transfer film according to claim 5, characterized in that: The fineness of the UV coating is no greater than 8µm.

7. The process for preparing a UV thermal transfer film according to claim 6, characterized in that: The polyester modified acrylic acid is prepared from methyl methacrylate, butyl acrylate, acrylic acid, tricarboxymethyl propane, dicumyl peroxide, neopentyl glycol, adipic acid and a diluent.

8. The process for preparing a UV thermal transfer film according to claim 3, characterized in that: The leveling agent is one or a mixture of polysiloxane leveling agents, acrylic acid or acrylic ester leveling agents.

9. The process for preparing a UV thermal transfer film according to claim 1, characterized in that: The light curing temperature is 50-70 degrees, and the curing time is 10-15 seconds.

10. The process for preparing a UV thermal transfer film according to claim 1, characterized in that: Before the surface treatment of the base film, the base film pretreatment is also included, and the base film pretreatment includes improving flatness and surface cleaning.

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