A kind of EVA composite transfer film and preparation method thereof

Abstract

The present invention relates to the field of transfer film technology, in particular to a kind of EVA composite transfer film and preparation method thereof.The EVA composite transfer film includes a PET base film, a first coating, a second coating, a laser film lamination, an aluminized layer, and a bonding layer stacked in sequence, wherein the first coating is composed of 99.5-99.9 parts and 0.1-0.5 parts of leveling agents, the second coating is composed of 99.70-99.95 parts of waterborne polyurethane modified resins and 0.05-0.30 parts of lubricants, and the bonding layer is composed of 40-50 parts of EVA, 10-15 parts of naphthenic oils, 0.1-0.3 parts of antioxidants, 10-15 parts of solution-polymerized butadiene styrene, 8-12 parts of organosilicon tackifiers, and 0.1-0.5 parts of photoinitiators. The EVA composite transfer film prepared by the present invention can conveniently separate the base film from the coating and the object to be attached after attachment, which is conducive to environmental protection and recycling, while having good mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of transfer films, in particular to an EVA composite transfer film and a preparation method thereof. Background Art

[0002] With the continuous development of thermal transfer technology, EVA composite transfer film, as an important transfer material, has been widely used in textiles, leather, electronic products and other fields. EVA is an ethylene-vinyl acetate copolymer with good flexibility, chemical resistance and weather resistance. It is often used to prepare various films, packaging materials, industrial materials, etc. However, in the existing technology, EVA composite transfer film has the following problems:

[0003] 1. When recycling waste products, the existing EVA composite film has too high fastness, making it difficult to separate the base film of the composite film from the adhered object, making recycling and sorting difficult and not conducive to environmental protection;

[0004] 2. The pattern transfer quality is also unstable, which is manifested in poor pattern clarity and color uniformity, affecting the transfer quality and product appearance quality.

[0005] Therefore, we propose an EVA composite transfer film and a preparation method thereof. Summary of the Invention

[0006] The object of the present invention is to provide an EVA composite transfer film and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A method for preparing an EVA composite transfer film comprises the following steps:

[0009] Step S1: uniformly mixing a water-based acrylic modified resin and a leveling agent to prepare a first coating; applying the first coating to the surface of the PET base film through an anilox roller, and drying to form a first coating layer;

[0010] Step S2: uniformly mixing a waterborne polyurethane modified resin and a lubricant to prepare a second coating; applying the second coating to the surface of the first coating using an anilox roller, and drying the coating to form a second coating;

[0011] Step S3: performing laser film pressing on the second coating layer to form a laser film pressing layer;

[0012] Step S4: Aluminum is plated on the surface of the laser film laminate by a vacuum aluminum plating process to form an aluminum plating layer;

[0013] Step S5: After the EVA hot melt adhesive is melted, it is coated on the surface of the aluminum-plated layer through an anilox roller. After solidification, an adhesive layer is formed, and the adhesive layer is slit and rolled to obtain an EVA composite transfer film.

[0014] Furthermore, the water-based acrylic modified resin in step S1 is water-soluble acrylic modified polyester resin 575-2, with a solid content of 75%.

[0015] Furthermore, the first coating in step S1 includes the following components by weight: 99.5-99.9 parts of water-based acrylic modified resin and 0.1-0.5 parts of leveling agent.

[0016] Furthermore, the wet coating amount of the first coating in step S1 is 6-8 g / m 2 .

[0017] Furthermore, the preparation process of the waterborne polyurethane modified resin in step S2 is as follows:

[0018] Step (1): Under nitrogen protection, the dried polytetramethylene glycol and dihydroxy-terminated silicone oil are mixed evenly, isophorone diisocyanate and dibutyltin dilaurate are added and mixed evenly, the temperature is raised to 70-80° C., and the reaction is carried out for 2-3 hours to obtain a polyurethane prepolymer;

[0019] Step (2): uniformly mixing a polyurethane prepolymer, 2,2-dihydroxymethylbutyric acid and 1,4-dihydroxybutane, raising the temperature to 80-90° C., reacting for 2-3 hours, adding hydroxyethyl methacrylate and mixing uniformly, cooling to 30-40° C., dripping 11-mercaptoundecanoxytrimethylsilane, dripping for 1-2 hours, and reacting for 2-3 hours; then adding triethylamine to adjust the pH to 6-7, adding deionized water for emulsification, adding isophorone diamine, and reacting for 1-2 hours to obtain a waterborne polyurethane modified resin.

[0020] In the above technical solution, bihydroxyl-terminated silicone oil and polytetramethylene glycol are used as raw materials, which react with isophorone diisocyanate to generate a polyurethane prepolymer. The bihydroxyl-terminated silicone oil serves as a modifier and is incorporated into the main chain structure of the polyurethane through emulsion copolymerization. After the chain extension reaction, hydroxyethyl methacrylate is added for end-capping treatment, and then 11-mercaptoundedecyloxytrimethylsilane is added. The siloxane and the hydrophobic long chain are connected to the end group through a click chemistry reaction, thereby reducing the free energy of the coating surface and enhancing the surface hydrophobicity. The excellent mechanical properties of polyurethane are combined with the outstanding hydrophobicity of silicone to produce a waterborne polyurethane modified resin.

[0021] Furthermore, in the step (1), the mass ratio of polytetrahydrofuran diol to dihydroxy-terminated silicone oil is 1:(0.06-0.10).

[0022] Furthermore, in the step (1), the mass of isophorone diisocyanate is 0.4-0.5 times the mass of polytetrahydrofuran diol.

[0023] Furthermore, in step (1), the mass of dibutyltin dilaurate is 0.4-0.6% of the mass of isophorone diisocyanate.

[0024] Furthermore, in step (2), the mass of 2,2-dihydroxymethylbutyric acid is 2-4% of the mass of the polyurethane prepolymer.

[0025] Furthermore, in step (2), the mass of the polyurethane prepolymer of 1,4-dihydroxybutane is 3-5%.

[0026] Furthermore, in step (2), the mass of hydroxyethyl methacrylate is 3-5% of the mass of the prepolymer.

[0027] Furthermore, in step (2), the mass of 11-mercaptoundedecyloxytrimethylsilane is 1.5-2.0 times the mass of hydroxyethyl methacrylate.

[0028] Furthermore, the mass of the deionized water in step (2) is 1.5-2.0 times the mass of the polyurethane prepolymer.

[0029] Furthermore, the mass of isophorone diamine in step (2) is 10-12% of the mass of the polyurethane prepolymer.

[0030] Furthermore, the second coating in step S2 includes the following components by weight: 99.70-99.95 parts of waterborne polyurethane modified resin and 0.05-0.30 parts of lubricant.

[0031] Furthermore, the lubricant is dimethyl silicone oil, which comes from Shandong Chuangyi Chemical Co., Ltd.

[0032] Furthermore, the mesh number of the anilox roller is 100-250 meshes.

[0033] Furthermore, the drying temperature is 70-90°C.

[0034] Furthermore, the wet coating amount of the second coating in step S2 is 6-8 g / m 2 .

[0035] Furthermore, the process conditions of the laser film pressing in step S3 are: temperature 155-175° C., speed 40-50 m / min.

[0036] Furthermore, the process conditions for vacuum aluminum plating in step S4 are: vacuum degree 0.001-0.010 Pa, aluminum evaporation temperature 1200-1400°C.

[0037] Furthermore, the thickness of the aluminum plating layer in step S4 is 0.05-0.08 μm.

[0038] Furthermore, the preparation process of the EVA hot melt adhesive in step S5 is as follows:

[0039] Step 1: Allyltriethoxysilane, dimethoxydimethylsilane and trimethoxymethylsilane are mixed evenly, the temperature is raised to 60-70°C, sodium hydroxide solution is added and mixed evenly, a mixed solution of boric acid and methanol is added dropwise for 1-2 hours, the mixture is reacted for 1-2 hours, and the mixture is filtered and distilled under reduced pressure to obtain an organosilicon tackifier;

[0040] Step 2: Mix EVA, cyclohexane oil and antioxidant evenly, heat to 120-130°C, add solution-polymerized styrene butadiene and silicone tackifier and mix evenly, cool to 110-120°C, add photoinitiator and mix evenly, cool to room temperature to prepare EVA hot melt adhesive.

[0041] In the above technical solution, a silicone thickener is prepared by reacting allyltriethoxysilane, dimethoxydimethylsilane, trimethoxymethylsilane and boric acid as raw materials; by adding a photoinitiator, after UV light exposure, the photoinitiator decomposes active free radicals, which can cause the random carbon-carbon double bonds in the soluble butadiene styrene and the carbon-carbon double bonds in the silicone thickener to undergo polymerization and cross-linking to form a three-dimensional network structure, thereby improving the cohesive strength of the EVA hot melt adhesive, thereby greatly improving the heat resistance of the hot melt adhesive; among them, cyclohexane oil as a plasticizer can improve the plasticity, flexibility and adhesion of the hot melt adhesive; the silicone thickener can increase the viscosity of the hot melt adhesive, improve its adhesion and bonding strength.

[0042] Furthermore, in the step 1, the mass ratio of allyltriethoxysilane, dimethoxydimethylsilane and trimethoxymethylsilane is 1:(0.8-1.0):(0.9-1.1).

[0043] Furthermore, the mass of the sodium hydroxide solution in step 1 is 3-5% of the mass of allyltriethoxysilane, and its concentration is 0.5-1.0 mol / L.

[0044] Furthermore, the mass ratio of the boric acid to methanol is 1:(3-4), and the mass of the boric acid is 0.4-0.6 times the mass of allyltriethoxysilane.

[0045] Furthermore, the EVA hot melt adhesive in step 2 includes the following components by weight: 40-50 parts of EVA, 10-15 parts of cyclohexane oil, 0.1-0.3 parts of antioxidant, 10-15 parts of solution-polymerized butadiene styrene, 8-12 parts of silicone tackifier, and 0.1-0.5 parts of photoinitiator.

[0046] Furthermore, the antioxidant is 2,6-di-tert-butyl-p-methylphenol.

[0047] Furthermore, the photoinitiator is methyl benzoylformate.

[0048] Furthermore, the melting temperature in step S5 is 140-150°C.

[0049] Furthermore, the curing process conditions in step S5 are: irradiation with 360-400nm ultraviolet light for 30-50min, irradiation intensity of 20-25mW / cm 2 .

[0050] Furthermore, the thickness of the bonding layer is 0.01-0.50 mm.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The present invention relates to an EVA composite transfer film and its preparation method. By combining the excellent mechanical properties of polyurethane with the outstanding hydrophobicity of silicone, a water-based polyurethane-modified resin is produced. This resin is then reacted with a lubricant to produce a second coating. This coating exhibits excellent film pressing properties, reduces the surface energy and viscosity of the coating, improves wettability and leveling, and prevents the applied film from sticking to the plate during film pressing, thereby enhancing the transfer process and pattern quality.

[0053] 2. The present invention provides an EVA composite transfer film and a preparation method thereof. By adding a photoinitiator and after UV irradiation, the photoinitiator decomposes active free radicals, which can cause the random carbon-carbon double bonds in the soluble butadiene styrene and the carbon-carbon double bonds in the silicone thickener to undergo polymerization and cross-linking to form a three-dimensional network structure, thereby improving the cohesive strength of the EVA hot melt adhesive, enhancing its bonding performance and heat resistance, and using it as a bonding layer to achieve bonding and reinforcement in the composite transfer film, while improving the heat resistance and strength of the transfer film.

[0054] 3. The EVA transfer film developed by the present invention can replace the existing composite film material EVA film. After lamination, the surface base film can be easily separated from the coating and the adhered object, which is conducive to environmental protection and recycling. In addition, the EVA transfer film has anti-scratch performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0056] Figure 1 It is a structural diagram of the EVA composite transfer film of the present invention. DETAILED DESCRIPTION

[0057] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0058] In this embodiment, the water-based acrylic modified resin is a water-soluble acrylic modified polyester resin 575-2 with a solid content of 75%, which is sourced from Jiangyin Liren Chemical Co., Ltd.; the leveling agent is BYK-358N, which is sourced from Dongguan Haoyouduo New Materials Co., Ltd.; the PET base film is 1040 mm wide and 75 μm thick, with the product number arb-YG5001, which is sourced from Xiamen Airibao New Materials Technology Co., Ltd.; the lubricant is dimethyl silicone oil, which is sourced from Shandong Chuangyi Chemical Co., Ltd.; the laser film is CY-H001 with a thickness of 0.3 mm, which is sourced from Dongguan Chaoyuan Plastic Technology Co., Ltd. Co., Ltd.; Aluminum: aluminum wire 0.2mm, item number 1060, aluminum content 99.6%, sourced from Dongguan Yangtai Metal Materials Co., Ltd.; Polytetramethylene glycol: Mn=2000, sourced from Jiangsu Haolong Chemical Co., Ltd.; Double-ended hydroxyl silicone oil: hydroxyl content 6-12%, sourced from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.; EVA: vinyl acetate content is 28%, South Korea Hanwha 1528, sourced from Suzhou Xianxianfa Plastic Technology Co., Ltd.; Naphthenic oil: Xinjiang Karamay 4010, sourced from Shandong Taichang Petrochemical Technology Co., Ltd.; Solution-polymerized butadiene styrene: brand SSBR 2150GC, styrene content 29%, sourced from Xiamen Mingjia New Materials Co., Ltd.

[0059] In the following examples and comparative examples, 1 part is equal to 10 g.

[0060] Example 1: A method for preparing an EVA composite transfer film, comprising the following steps:

[0061] Step S1: 99.5 parts of a water-based acrylic modified resin and 0.1 parts of a leveling agent are mixed evenly to prepare a first coating; the first coating is applied to the surface of the PET base film using an anilox roller and dried (drying temperature is 70° C.) to form a first coating layer;

[0062] Step S2: 99.70 parts of a waterborne polyurethane modified resin and 0.30 parts of a lubricant are mixed evenly to prepare a second coating; the second coating is applied to the surface of the first coating using an anilox roller and dried (drying temperature is 70° C.) to form a second coating;

[0063] Step S3: performing laser film pressing (temperature 155° C., speed 40 m / min) on the second coating layer to form a laser film pressing layer;

[0064] Step S4: Aluminum is plated on the surface of the laser film laminate by a vacuum aluminum plating process (vacuum degree 0.001 Pa, aluminum evaporation temperature 1200° C.) to form an aluminum plating layer;

[0065] Step S5: After the EVA hot melt adhesive is melted, it is coated on the surface of the aluminum coating layer through an anilox roller and solidified (irradiated with 360nm ultraviolet light for 30min, irradiation intensity 20mW / cm 2 ), forming an adhesive layer, slitting and winding, and preparing an EVA composite transfer film;

[0066] The preparation process of the waterborne polyurethane modified resin in step S2 is as follows:

[0067] Step (1): Under nitrogen protection, 50 parts of dried polytetramethylene glycol and 3 parts of dihydroxy-terminated silicone oil were mixed evenly, 20 parts of isophorone diisocyanate and 0.08 parts of dibutyltin dilaurate were added and mixed evenly, the mixture was heated to 70° C., and the mixture was reacted for 2 hours to obtain a polyurethane prepolymer;

[0068] Step (2): 70 parts of a polyurethane prepolymer, 1.4 parts of 2,2-dihydroxymethylbutyric acid, and 2.1 parts of 1,4-dihydroxybutane were mixed uniformly, the mixture was heated to 80° C., and the mixture was reacted for 2 h. 2.1 parts of hydroxyethyl methacrylate was added and the mixture was mixed uniformly. The mixture was cooled to 30° C., 3.15 parts of 11-mercaptoundedecyloxytrimethylsilane was added dropwise over a period of 1 h, and the mixture was reacted for 2 h. Triethylamine was then added to adjust the pH to 6, the mixture was emulsified in 105 parts of deionized water, and 7 parts of isophoronediamine were added and the mixture was reacted for 1 h to obtain a waterborne polyurethane modified resin.

[0069] The preparation process of the EVA hot melt adhesive in step S5 is as follows:

[0070] Step 1: 5 parts of allyltriethoxysilane, 4 parts of dimethoxydimethylsilane and 4.5 parts of trimethoxymethylsilane were mixed evenly, the temperature was raised to 60°C, 0.15 g of 0.5 mol / L sodium hydroxide solution was added and mixed evenly, and a mixed solution of 2 parts of boric acid and 6 parts of methanol was added dropwise for 1 hour, and the mixture was reacted for 1 hour. After filtration and vacuum distillation, an organosilicon tackifier was obtained;

[0071] Step 2: Mix 40 parts of EVA, 10 parts of cyclohexane oil and 0.1 parts of 2,6-di-tert-butyl-p-methylphenol, heat to 120°C, add 10 parts of soluble polybutadiene styrene and 8 parts of silicone tackifier and mix evenly, cool to 110°C, add 0.1 parts of methyl benzoylformate and mix evenly, cool to room temperature to prepare EVA hot melt adhesive.

[0072] Example 2: A method for preparing an EVA composite transfer film, comprising the following steps:

[0073] Step S1: 99.6 parts of a water-based acrylic modified resin and 0.4 parts of a leveling agent are mixed evenly to prepare a first coating; the first coating is applied to the surface of the PET base film using an anilox roller and dried (drying temperature is 80° C.) to form a first coating layer;

[0074] Step S2: 99.80 parts of a waterborne polyurethane modified resin and 0.20 parts of a lubricant are mixed evenly to prepare a second coating; the second coating is applied to the surface of the first coating using an anilox roller, and dried (drying temperature is 80° C.) to form a second coating;

[0075] Step S3: performing laser film pressing (temperature 160° C., speed 45 m / min) on the second coating layer to form a laser film pressing layer;

[0076] Step S4: Aluminum is plated on the surface of the laser film laminate by a vacuum aluminum plating process (vacuum degree 0.005 Pa, aluminum evaporation temperature 1300° C.) to form an aluminum plating layer;

[0077] Step S5: After the EVA hot melt adhesive is melted, it is coated on the surface of the aluminum layer through an anilox roller and solidified (irradiated with 380nm ultraviolet light for 40min, with an irradiation intensity of 22mW / cm 2 ), forming an adhesive layer, slitting and winding, and preparing an EVA composite transfer film;

[0078] The preparation process of the waterborne polyurethane modified resin in step S2 is as follows:

[0079] Step (1): Under nitrogen protection, 80 parts of dried polytetramethylene glycol and 6.4 parts of dihydroxy-terminated silicone oil were mixed evenly, 36 parts of isophorone diisocyanate and 0.18 parts of dibutyltin dilaurate were added and mixed evenly, the mixture was heated to 75° C., and the mixture was reacted for 2.5 hours to obtain a polyurethane prepolymer;

[0080] Step (2): 80 parts of a polyurethane prepolymer, 2.4 parts of 2,2-dihydroxymethylbutyric acid, and 3.2 parts of 1,4-dihydroxybutane were mixed uniformly, the mixture was heated to 85° C., and the mixture was reacted for 2.5 hours. 3.2 parts of hydroxyethyl methacrylate were added and the mixture was mixed uniformly. The mixture was cooled to 35° C., 6 parts of 11-mercaptoundedecyloxytrimethylsilane were added dropwise over a period of 1.5 hours, and the mixture was reacted for 2.5 hours. Triethylamine was then added to adjust the pH to 6.5, the mixture was emulsified in 150 parts of deionized water, and 8.8 parts of isophoronediamine were added and the mixture was reacted for 1.5 hours to obtain a waterborne polyurethane modified resin.

[0081] The preparation process of the EVA hot melt adhesive in step S5 is as follows:

[0082] Step 1: 10 parts of allyltriethoxysilane, 9 parts of dimethoxydimethylsilane and 10 parts of trimethoxymethylsilane were mixed evenly, the temperature was raised to 65°C, 0.4 parts of 0.8 mol / L sodium hydroxide solution were added and mixed evenly, and a mixed solution of 5 parts of boric acid and 18 parts of methanol was added dropwise for 1.5 hours, and the mixture was reacted for 1.5 hours. After filtration and vacuum distillation, an organosilicon tackifier was obtained;

[0083] Step 2: Mix 45 parts of EVA, 12 parts of cyclohexane oil and 0.2 parts of 2,6-di-tert-butyl-p-methylphenol, heat to 125°C, add 12 parts of soluble polybutadiene styrene and 10 parts of silicone tackifier and mix evenly, cool to 115°C, add 0.3 parts of methyl benzoylformate and mix evenly, cool to room temperature to prepare EVA hot melt adhesive.

[0084] Example 3: A method for preparing an EVA composite transfer film, comprising the following steps:

[0085] Step S1: 99.9 parts of a water-based acrylic modified resin and 0.1 parts of a leveling agent are mixed evenly to prepare a first coating; the first coating is applied to the surface of the PET base film using an anilox roller and dried (drying temperature is 90° C.) to form a first coating layer;

[0086] Step S2: 99.95 parts of a waterborne polyurethane modified resin and 0.05 parts of a lubricant are mixed evenly to prepare a second coating; the second coating is applied to the surface of the first coating using an anilox roller and dried (drying temperature is 90° C.) to form a second coating;

[0087] Step S3: performing laser film pressing (temperature 175° C., speed 50 m / min) on the second coating layer to form a laser film pressing layer;

[0088] Step S4: Aluminum is plated on the surface of the laser film laminate by a vacuum aluminum plating process (vacuum degree 0.010 Pa, aluminum evaporation temperature 1400° C.) to form an aluminum plating layer;

[0089] Step S5: After the EVA hot melt adhesive is melted, it is coated on the surface of the aluminum layer through an anilox roller and solidified (irradiated with 400nm ultraviolet light for 50min, with an irradiation intensity of 25mW / cm 2 ), forming an adhesive layer, slitting and winding, and preparing an EVA composite transfer film;

[0090] The preparation process of the waterborne polyurethane modified resin in step S2 is as follows:

[0091] Step (1): Under nitrogen protection, 80 parts of dried polytetramethylene glycol and 8 parts of dihydroxy-terminated silicone oil were mixed evenly, 40 parts of isophorone diisocyanate and 0.24 parts of dibutyltin dilaurate were added and mixed evenly, the mixture was heated to 80° C., and the mixture was reacted for 3 hours to obtain a polyurethane prepolymer;

[0092] Step (2): 85 parts of a polyurethane prepolymer, 3.4 parts of 2,2-dihydroxymethylbutyric acid, and 4.25 parts of 1,4-dihydroxybutane were mixed uniformly, the mixture was heated to 90° C., and the mixture was reacted for 3 hours. 4.25 parts of hydroxyethyl methacrylate were added and the mixture was mixed uniformly. The mixture was cooled to 40° C., 8.5 parts of 11-mercaptoundedecyloxytrimethylsilane were added dropwise over a period of 2 hours, and the mixture was reacted for 3 hours. Triethylamine was then added to adjust the pH to 7, the mixture was emulsified in 170 parts of deionized water, and 10.2 parts of isophoronediamine were added and the mixture was reacted for 2 hours to obtain a waterborne polyurethane modified resin.

[0093] The preparation process of the EVA hot melt adhesive in step S5 is as follows:

[0094] Step 1: 10 parts of allyltriethoxysilane, 10 parts of dimethoxydimethylsilane and 11 parts of trimethoxymethylsilane were mixed evenly, the temperature was raised to 70°C, 0.5 parts of 1.0 mol / L sodium hydroxide solution were added and mixed evenly, and a mixed solution of 6 parts of boric acid and 24 parts of methanol was added dropwise for 2 hours, and the mixture was reacted for 2 hours. After filtration and vacuum distillation, an organosilicon tackifier was obtained;

[0095] Step 2: Mix 50 parts of EVA, 15 parts of cyclohexane oil and 0.3 parts of 2,6-di-tert-butyl-p-methylphenol, heat to 130°C, add 15 parts of soluble polybutadiene styrene and 12 parts of silicone tackifier and mix evenly, cool to 120°C, add 0.5 parts of methyl benzoylformate and mix evenly, cool to room temperature to prepare EVA hot melt adhesive.

[0096] Comparative Example 1: The second coating in step S1 includes the following components by weight: 99.7 parts of aqueous polyurethane emulsion and 0.3 parts of lubricant; Comparative Example 1 does not include the preparation process of the aqueous polyurethane modified resin in step S1, and the aqueous polyurethane modified resin is replaced with an unmodified aqueous polyurethane emulsion of the same mass (model 1624, solid content of 38%, sourced from Shenzhen Yoshida Chemical Co., Ltd.), and the other steps and processes are the same as in Example 1.

[0097] Comparative Example 2: The EVA hot melt adhesive in step 2 includes the following components by weight: 40 parts of EVA, 10 parts of cyclohexane oil, 0.1 parts of antioxidant, 10 parts of solution-polymerized butadiene styrene, 1 part of silicone tackifier, and 0.1 parts of photoinitiator. Comparative Example 2 adds 1 part of silicone tackifier, and the other steps and processes are the same as Example 1.

[0098] Comparative Example 3: A method for preparing an EVA composite transfer film, comprising the following processes:

[0099] The preparation process of the waterborne polyurethane modified resin in step S2 is as follows:

[0100] Step (1): Under nitrogen protection, 80 parts of dried polytetramethylene glycol and 6.4 parts of dihydroxy-terminated silicone oil were mixed evenly, 36 parts of isophorone diisocyanate and 0.18 parts of dibutyltin dilaurate were added and mixed evenly, the mixture was heated to 75° C., and the mixture was reacted for 2.5 hours to obtain a polyurethane prepolymer;

[0101] Step (2): 80 parts of a polyurethane prepolymer, 2.4 parts of 2,2-dihydroxymethylbutyric acid, and 3.2 parts of 1,4-dihydroxybutane were mixed uniformly, the mixture was heated to 85° C., and the mixture was reacted for 2.5 hours. 3.2 parts of hydroxyethyl methacrylate were added and mixed uniformly. The mixture was cooled to 35° C., 1.6 parts of 11-mercaptoundedecyloxytrimethylsilane were added dropwise over a period of 1.5 hours, and the mixture was reacted for 2.5 hours. Triethylamine was then added to adjust the pH to 6.5, the mixture was emulsified in 150 parts of deionized water, and 8.8 parts of isophoronediamine were added and the mixture was reacted for 1.5 hours to obtain a waterborne polyurethane modified resin.

[0102] Compared with Example 2, the mass of 11-mercaptoundedecyloxytrimethylsilane in step (2) of Comparative Example 3 is 0.2 times the mass of hydroxyethyl methacrylate.

[0103] Comparative Example 4: A method for preparing an EVA composite transfer film, comprising the following processes:

[0104] The preparation process of the EVA hot melt adhesive in step S5 is as follows:

[0105] Step 1: 0.1 parts of allyltriethoxysilane, 10 parts of dimethoxydimethylsilane and 10 parts of trimethoxymethylsilane were mixed evenly, the temperature was raised to 65°C, 0.4 parts of 0.8 mol / L sodium hydroxide solution were added and mixed evenly, and a mixed solution of 5 parts of boric acid and 18 parts of methanol was added dropwise for 1.5 hours, and the mixture was reacted for 1.5 hours. After filtration and vacuum distillation, an organosilicon tackifier was obtained;

[0106] Step 2: Evenly mix 45 parts of EVA, 12 parts of naphthenic oil, and 0.2 parts of 2,6-di-tert-butyl-p-methylphenol, heat to 125°C, add 12 parts of soluble polybutadiene styrene and 10 parts of silicone tackifier, mix evenly, cool to 115°C, add 0.3 parts of methyl benzoylformate, mix evenly, and cool to room temperature to prepare EVA hot melt adhesive;

[0107] Compared with Example 2, the mass ratio of allyltriethoxysilane, dimethoxydimethylsilane and trimethoxymethylsilane in step 1 of Comparative Example 4 is 0.1:1:1, and the other steps are the same as those in Example 2.

[0108] Experiment: Take the EVA composite transfer films obtained in Examples 1-3 and Comparative Examples 1-4, prepare samples, test their properties and record the test results:

[0109] Tear strength was determined according to GB / T 16578.1-2008, Plastic Film and Sheeting — Determination of Tear Resistance — Part 1: Trouser Tear Method. The following experimental steps were used: a 150 mm long and 50 mm wide specimen was notched in the center with a length of 75 mm. The specimen was tested using a tensile testing machine at a speed of 200 mm / min, and the tear strength was calculated.

[0110] Transfer performance test: The EVA composite transfer film is made into a sample with a size of 100m×100mm. The sample is transferred to the surface of the substrate. The laser film lamination is directly presented. The quality of the laser film lamination is observed and the observation results are recorded to evaluate the transfer performance.

[0111] Test results

[0112] Tear strength kN / m Transfer performance Example 1 3.7 The pattern is complete and clear Example 2 4.2 The pattern is complete and clear Example 3 3.9 The pattern is complete and clear Comparative Example 1 3.2 Incomplete pattern Comparative Example 2 2.8 The pattern is complete and clear Comparative Example 3 3.3 The pattern is not clear Comparative Example 4 3.5 The pattern is complete and clear

[0113] According to the data in the above table, we can clearly draw the following conclusions:

[0114] 1. Compared with Examples 1-3, the transfer performance of the product obtained in Comparative Example 1 is reduced, indicating that compared with the unmodified aqueous polyurethane emulsion, the aqueous polyurethane modified resin prepared by the present invention has low surface energy and hydrophobic properties, thereby being able to better separate from the substrate during the transfer process, ensuring the complete transfer of the pattern and improving the quality of the transferred pattern.

[0115] 2. Compared with Examples 1-3, the tear strength of the product obtained in Comparative Example 2 decreased, indicating that reducing the amount of silicone tackifier will lead to a decrease in the performance of the hot melt adhesive; the transfer performance of the product obtained in Comparative Example 3 decreased, indicating that the performance of the water-based polyurethane modified resin prepared by the present invention is affected by its component ratio. By selecting a component ratio within the said range, a material with low surface energy and hydrophobic properties can be prepared, thereby improving the quality of the transfer pattern.

[0116] 3. Compared with Examples 1-3, the tear strength of the product obtained in Comparative Example 4 is reduced. It can be seen that the performance of the EVA hot melt adhesive prepared by the present invention is affected by the ratio of each reagent in its preparation process. By selecting a mass ratio within the range, an EVA hot melt adhesive with better strength is prepared.

[0117] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0118] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing an EVA composite transfer film, characterized in that: The steps include: Step S1: uniformly mixing a water-based acrylic modified resin and a leveling agent to prepare a first coating; applying the first coating to the surface of the PET base film through an anilox roller, and drying to form a first coating layer; Step S2: uniformly mixing a waterborne polyurethane modified resin and a lubricant to prepare a second coating; applying the second coating to the surface of the first coating using an anilox roller, and drying the coating to form a second coating; Step S3: performing laser film pressing on the second coating layer to form a laser film pressing layer; Step S4: Aluminum is plated on the surface of the laser film laminate by a vacuum aluminum plating process to form an aluminum plating layer; Step S5: After the EVA hot melt adhesive is melted, it is coated on the surface of the aluminum coating layer by an anilox roller. After solidification, an adhesive layer is formed, and the adhesive layer is slit and rolled to obtain an EVA composite transfer film; The preparation process of the waterborne polyurethane modified resin in step S2 is as follows: Step (1): Under nitrogen protection, the dried polytetramethylene glycol and dihydroxy-terminated silicone oil are mixed evenly, isophorone diisocyanate and dibutyltin dilaurate are added and mixed evenly, the mixture is heated to 70-80°C, and the mixture is reacted for 2-3 hours to obtain a polyurethane prepolymer; Step (2): uniformly mix the polyurethane prepolymer, 2,2-dihydroxymethylbutyric acid and 1,4-dihydroxybutane, heat to 80-90°C, react for 2-3h, add hydroxyethyl methacrylate and mix evenly, cool to 30-40°C, dropwise add 11-mercaptoundecanyloxytrimethylsilane, drip over 1-2h, and react for 2-3h; then add triethylamine to adjust the pH to 6-7, add deionized water for emulsification, add isophorone diamine, and react for 1-2h to obtain a waterborne polyurethane modified resin; The preparation process of the EVA hot melt adhesive in step S5 is as follows: Step 1: Allyltriethoxysilane, dimethoxydimethylsilane and trimethoxymethylsilane are mixed evenly, the temperature is raised to 60-70°C, sodium hydroxide solution is added and mixed evenly, a mixed solution of boric acid and methanol is added dropwise for 1-2 hours, the mixture is reacted for 1-2 hours, and the mixture is filtered and distilled under reduced pressure to obtain an organosilicon tackifier; Step 2: Mix EVA, cyclohexane oil and antioxidant evenly, heat to 120-130°C, add solution-polymerized styrene butadiene and silicone tackifier and mix evenly, cool to 110-120°C, add photoinitiator and mix evenly, cool to room temperature to prepare EVA hot melt adhesive.

2. The method for preparing an EVA composite transfer film according to claim 1, wherein: The first coating in step S1 includes the following components by weight: 99.5-99.9 parts of water-based acrylic modified resin and 0.1-0.5 parts of leveling agent.

3. The method for preparing an EVA composite transfer film according to claim 1, wherein: The second coating in step S2 includes the following components by weight: 99.70-99.95 parts of waterborne polyurethane modified resin and 0.05-0.30 parts of lubricant.

4. The method for preparing an EVA composite transfer film according to claim 1, wherein: The process conditions of the laser film pressing in step S3 are: temperature 155-175° C., speed 40-50 m / min.

5. The method for preparing an EVA composite transfer film according to claim 1, wherein: The process conditions for vacuum aluminum plating in step S4 are: vacuum degree 0.001-0.010 Pa, aluminum evaporation temperature 1200-1400°C.

6. The method for preparing an EVA composite transfer film according to claim 1, wherein: The EVA hot melt adhesive in step 2 comprises the following components by weight: 40-50 parts of EVA, 10-15 parts of naphthenic oil, 0.1-0.3 parts of antioxidant, 10-15 parts of solution-polymerized butadiene styrene, 8-12 parts of organosilicon tackifier, and 0.1-0.5 parts of photoinitiator.

7. The method for preparing an EVA composite transfer film according to claim 1, wherein: The curing process conditions in step S5 are: irradiation with 360-400 nm ultraviolet light for 30-50 min, with an irradiation intensity of 20-25 mW / cm 2 .

8. An EVA composite transfer film prepared according to the preparation method according to any one of claims 1 to 7.

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