Processing method for heat transfer printing fabric based on UV-printed three-dimensional graphics

Abstract

A processing method of heat transfer printing fabric based on UV-printed three-dimensional graphics is provided. The processing method includes the following steps: applying hot-melt adhesive onto a release layer, drying and preparing a hot-melt adhesive layer; performing UV inkjet printing on the hot-melt adhesive layer to form graphics, and laminating a protective layer onto the surface of the hot-melt adhesive layer to obtain a hot-melt adhesive layer with graphics; and removing the release layer from the hot-melt adhesive layer with graphics, spreading the hot-melt adhesive layer onto a fabric, pressing at a temperature of 140-160° C., removing the protective layer and obtaining printed fabric with three-dimensional graphics.

Description

CROSS-REFERENCE TO THE RELATED APPLICATIONS

[0001] This application is based upon and claims priority to Chinese Patent Application No. 202510097970.6, filed on Jan. 22, 2025, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention relates to a field of fabric printing technology, specifically involving a processing method for heat transfer printing fabric with ultraviolet (UV)-printed three-dimensional graphics.BACKGROUND

[0003] Three-dimensional colored graphics prepared by heat transfer printing are characterized by resistance to sunlight and water washing, strong color fastness and rich colors. Additionally, the graphics are highly realistic, with intricate designs, clear layers, and a strong sense of three-dimensionality, favorited by consumers.

[0004] Existing heat transfer printing processes mainly include offset printing, gravure or letterpress printing, screen printing and digital printing. However, these processes are relatively complex and require substantial investment in equipment. Screen printing, for example, includes the following steps: firstly, preparing screen and mixing colors; then applying the colors on engraving film or silicone rubber, followed by baking, cutting out desired graphic or patterns by laser, manually removing excess waste, and finally pressing. Preparing multi-colored graphics, especially graphics with a thickness greater than 0.3 millimeters, often requires multiple repetitions of the processes of preparing the screen, mixing colors, applying colors and baking. This process has high screen preparation costs, is complex, requires significant equipment investment, and is not suitable for small-batch production and personalized customization scenarios. If only single-color graphics are to be made, the process can be simplified. However, the process still requires inputting desired graphics on a computer using engraving film or silicone rubber, cutting out the desired graphics with a laser cutting machine, manually removing excess waste around the desired graphics, and then heat transfer printing the desired graphics onto fabrics. This process is still relatively complex and costly. For instance, Patent CN109440500A proposes a process of high-definition screen printing, which divides a pattern area and a non-pattern area on the fabric. Using the screen as a support, the screen is stretched on a frame to obtain a screen plate. A paste-blocking layer is applied to the area on the screen plate corresponding to the non-pattern area of the fabric. The pattern area of the fabric is then printed with paste to form a paste layer. This printing process eliminates the need for laser cutting and offers high positioning accuracy and good printing effects. However, the process of preparing the screen plate is complex and costly.

[0005] Patent CN110667293A proposes a positioning foil stamping method for digital inkjet heat transfer printing fabric. A release layer and an ink absorption layer are first coated on a carrier. A digital inkjet printing machine is used to print sublimation ink and digital inkjet hot-melt adhesive ink in register onto the carrier. The carrier is then combined with the polyester fabric to be printed and pressed to obtain a printed fabric with positioning hot-melt adhesive. This process eliminates steps of plate-making and printing of traditional foil stamping method, making it environmentally friendly and energy-saving, and significantly reducing production time and costs. However, this process relies on specific digital inkjet hot-melt adhesives, which are prone to clogging the nozzles and have slow curing speeds after printing. Printed products require a long drying period, resulting in a longer production cycle and an inability to meet demands of flexible production for multiple small batches and personalized custom printing.SUMMARY

[0006] The objective of the present invention is to overcome the deficiencies and shortcomings of existing printed fabric and to provide a processing method of heat transfer printing fabric based on UV-printed three-dimensional graphics, which can produce graphics with a strong dimensionality and adhesion. The processing method is simple and has a short production cycle, meeting the flexible production demands for a variety of patterns.

[0007] Another objective of the present invention is to provide a printed fabric.

[0008] The above objectives of the present invention are achieved through the following technical solutions:

[0009] The present invention protects a processing method of heat transfer printing fabric based on UV-printed three-dimensional graphics, including the following steps:

[0010] step 1, applying hot-melt adhesive onto a release layer, drying and preparing a hot-melt adhesive layer;

[0011] step 2, performing UV inkjet printing on the hot-melt adhesive layer to form graphics, and laminating a protective layer onto the surface of the hot-melt adhesive layer to obtain a hot-melt adhesive layer with graphics; and

[0012] step 3, removing the release layer from the hot-melt adhesive layer with graphics, spreading the hot-melt adhesive layer onto a fabric, pressing at a temperature of 140-160° C., removing the protective layer and obtaining printed fabric with three-dimensional graphics.

[0013] The processing method of heat transfer printing fabric based on UV-printed three-dimensional graphics according to the present invention involves UV inkjet printing on the hot-melt adhesive layer, wherein the ink dries and solidifies instantly after printing, resulting in high production efficiency and minimal ink diffusion. The hot-melt adhesive layer with graphics is then heat-transferred onto the fabric to produce graphics with a strong dimensionality and adhesion. By combining UV printing and heat transfer processes, the present invention can achieve three-dimensional graphics printing with multiple colors on fabric in one step. The processing method is simple and convenient, eliminating the need for plate making, scraping and laser cutting, resulting in a short production cycle and lower costs, thus meeting the flexible production demands for personalized custom printing.

[0014] In some embodiments, during the step 2, a UV irradiation is maintained throughout the UV inkjet printing process, with a UV light wavelength ranging from 365-425 nanometers (nm), preferably 365 nm.

[0015] In some embodiments, the UV inkjet printing process includes a secondary UV irradiation process, which includes:

[0016] step (1), a first UV irradiation, wherein a first UV light moves synchronously with inkjet printing components, causing the printed ink to solidify under the irradiation of the first UV light and forming printed graphics; and

[0017] step (2), a second UV irradiation, wherein the printed graphics formed in step (1) is further solidified and finalized under the irradiation of a second UV light.

[0018] The first UV irradiation allows the UV ink to solidify instantly, restricting ink diffusion and eliminating any need for additional drying treatment. After the second UV irradiation, graphics is further solidified and finalized, making a significant hardness difference between graphics area and surrounding hot-melt adhesive. This makes it easier to remove the surrounding hot-melt adhesive during the subsequent heat transfer process, preventing stringing and residue.

[0019] The ink used in the UV inkjet printing of the present invention has no specific restrictions and can be selected from commercially available conventional UV inks, including but not limited to UV ink from Hunan Shanxin New Material Science and Technology Co., Ltd., UV ink from Zhuhai Print-Rite New Materials Corporation Limited or soft UV ink from INKBANK Group Inc.

[0020] In some embodiments, during the step 3, the pressing time is 1-10 seconds, and the pressure is 0.1-1 megapascals (MPa).

[0021] In some embodiments, the fabric can be at least one of cotton fibers, linen fibers, nylon fibers, acrylic fibers, polyester fibers or animal furs.

[0022] The hot-melt adhesive used in the present invention can be selected from conventional materials in the field, including but not limited to polyamide (PA), ethylene-vinyl acetate copolymer (EVA), and / or thermoplastic polyurethane elastomer (TPU). Preferably, the hot-melt adhesive is EVA hot-melt adhesive or EVA / TPU composite hot-melt adhesive.

[0023] In some embodiments, a mass ratio of EVA to TPU in the EVA / TPU composite hot-melt adhesive is (1.4-3):1. The specific combination of EVA and TPU can overcome low tensile strength and poor water-washing resistance of EVA hot-melt adhesive, enhancing properties of resistance to deformation and color fastness to washing.

[0024] Preferably, the EVA / TPU composite hot-melt adhesive includes the following components in part by mass: 15-25 parts of TPU, 35-45 parts of EVA, 10-14 parts of tackifier resin, 3-8 parts of film-forming agent, 1-5 parts of viscosity modifier, 0.1-3 parts of hardening resin, 0.1-3 parts of dispersant, 0.1-3 parts of humectant, and 0.1-3 parts of curing agent.

[0025] Optionally, the tackifier resin is a polyvinyl acetate.

[0026] Optionally, the film-forming agent is a polyurethane resin and / or an acrylic resin.

[0027] Optionally, the viscosity modifier is a low-density polyethylene (LDPE) and / or a linear low-density polyethylene (LLDPE).

[0028] Optionally, the hardening resin is preferably at least one of homopolymer polypropylene, polypropylene block copolymer, or polypropylene random copolymer. The hardening resin is used to increase material's hardness, enhance shearability and facilitate waste removal.

[0029] Compared with prior art, the beneficial effects of the present invention are as follows:

[0030] The present invention provides a processing method of heat transfer printing fabric based on UV-printed three-dimensional graphics. The UV inkjet printing on a hot-melt adhesive layer allows the ink to dry and solidify instantly after printing, resulting in high production efficiency and restricting ink diffusion. A hot-melt adhesive layer with graphics is then heat-transferred onto a fabric to produce graphics with a strong dimensionality and adhesion. By combining UV printing and heat transfer processes, the present invention can achieve three-dimensional graphics printing with multiple colors on fabric in one step. The processing method is simple and convenient, eliminating the need for plate making, scraping and laser cutting, resulting in a short production cycle and lower costs, thus meeting the flexible production demands for personalized custom printing.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0032] FIGURE is a photograph of a product obtained from the processing method for heat transfer printing fabric with three-dimensional graphics in Embodiment 1 of the present invention.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present application is described in further detail below in conjunction with embodiments, the embodiments, however, do not limit the invention in any form. Unless otherwise stated, raw materials and reagents used in the following embodiments of the present invention are commercially available products.Embodiment 1

[0034] A processing method for heat transfer printing fabric with three-dimensional graphics includes the following steps.

[0035] Step 1 is, applying hot-melt adhesive onto a release layer, drying and preparing a hot-melt adhesive layer.

[0036] Specifically, a hot-melt adhesive coating is applied onto a surface of a 50 micrometer (μm) heavy-duty release film and dried. A coating machine has 7 sections of ovens, 4 meters long for each, with a transfer speed of 12 meter per minute. A first section of oven has a temperature of 70° C., a second section of oven has a temperature of 80° C., a third section of oven has a temperature of 110° C., a fourth section of oven has a temperature of 150° C., a fifth section of oven has a temperature of 150° C., a sixth section of oven has a temperature of 140° C., and a seventh section of oven has a temperature of 100° C. The coating thickness is 65 μm. After exiting the ovens, the heavy-duty release film passes through a cooling roller to cool down and is laminated with a 25 μm release film for winding to obtain a hot-melt adhesive film. Stepwise temperature allows the solvent to evaporate slowly, reducing issues such as pseudo-dry, bubbles, crystal dots, and solvent residue that may affect performance.

[0037] The hot-melt adhesive coating is prepared by thoroughly mixing the following components in part by mass at 60° C.: 20 parts of TPU (WHT-1150, Wanhua Chemical Group Co., Ltd.), 40 parts of EVA (150, Mitsui Chemicals, Japan), 12 parts of polyvinyl acetate (S0105, Wacker Chemie AG, Japan), 5 parts of polyurethane resin (627, Leader Formula Group, Taiwan), 2 parts of LDPE (1C7A, Sinopec Beijing Yanshan Company), 1 part of polypropylene (MU4016, Sinopec Beijing Yanshan Company), 2 parts of dispersant (330, Dongguan Risun New Material Company), 2 parts of humectant (TEGO 410, TEGO, Germany), 2 parts of curing agent (AE808, Guangzhou Yaxin New Material Company), 1 part of leveling agent (BYK-420, BYK, Germany), and 15 parts of solvent (toluene, acetone and N,N-Dimethylformamide (DMF)).

[0038] Step 2 is, performing UV inkjet printing on the hot-melt adhesive layer to form graphics and obtaining a hot-melt adhesive film with graphics.

[0039] Specifically, the 25 μm release film on the surface of the hot-melt adhesive film is removed. UV inkjet printing is carried out on the hot-melt adhesive film using a UV digital printer. UV ink is selected from Zhuhai Print-Rite New Materials Corporation Limited. An inkjet printing component of the UV digital printer is equipped with a first UV lamp (365 nanometers, 25 Watts), which is configured to move synchronously with an inkjet head to instantly cure the printed ink. A second UV lamp (365 nanometers, 30 Watts) is added downstream of a working table of the UV digital printer for irradiation, which is configured to cure and set the printed graphics. Then, a polyethylene (PE) protective film is applied to obtain a hot-melt adhesive film with graphics.

[0040] Step 3 is, spreading the hot-melt adhesive layer onto a fabric, pressing and obtaining printed fabric with three-dimensional graphics.

[0041] Specifically, the 50 μm heavy-duty release film underneath the hot-melt adhesive film with graphics is removed. The hot-melt adhesive film with graphics is then placed on a cotton fabric. A heat press machine is used to press it at 150° C. for 2 seconds, at a pressure of 0.6 MPa. The PE protective film is then removed, transferring the excess hot-melt adhesive around the graphics to the protective film, while the graphics are completely bonded to the cotton fabric, resulting in a printed fabric with three-dimensional graphics.Embodiment 2

[0042] A processing method for heat transfer printing fabric with three-dimensional graphics includes the following steps.

[0043] Step 1 is, applying hot-melt adhesive onto a release layer, drying and preparing a hot-melt adhesive layer.

[0044] Specifically, a hot-melt adhesive coating is applied onto a surface of a 50 μm heavy-duty release film and dried. A coating machine has a temperature of 150° C., with a transfer speed of 12 meter per minute. The coating thickness is 50 μm. After exiting the ovens, the heavy-duty release film passes through a cooling roller to cool down and is laminated with a 25 μm release film for winding to obtain a hot-melt adhesive film. The hot-melt adhesive coating has the same components as in Embodiment 1.

[0045] Step 2 is, performing UV inkjet printing on the hot-melt adhesive layer to form graphics and obtaining a hot-melt adhesive film with graphics.

[0046] Specifically, the 25 μm release film on the surface of the hot-melt adhesive film is removed. UV inkjet printing is carried out on the hot-melt adhesive film using a UV digital printer. UV ink is selected from INKBANK Group Inc. An inkjet printing component of the UV digital printer is equipped with a first UV lamp (365-425 nanometers, 25 Watts), which is configured to move synchronously with an inkjet head to instantly cure the printed ink. A second UV lamp is added downstream of a working table of the UV digital printer for irradiation, which is configured to cure and set the printed graphics. Then, a PE protective film is applied to obtain a hot-melt adhesive film with graphics.

[0047] Step 3 is, spreading the hot-melt adhesive layer onto a fabric, pressing and obtaining printed fabric with three-dimensional graphics.

[0048] Specifically, the 50 μm heavy-duty release film underneath the hot-melt adhesive film with graphics is removed. The hot-melt adhesive film with graphics is then placed on a cotton fabric. A heat press machine is used to press it at 155° C. for 1 second, at a pressure of 0.8 MPa. The PE protective film is then removed, transferring the excess hot-melt adhesive around the graphics to the protective film, while the graphics are completely bonded to the cotton fabric, resulting in a printed fabric with three-dimensional graphics.Embodiment 3

[0049] A processing method for heat transfer printing fabric with three-dimensional graphics includes the following steps.

[0050] Step 1 is, applying hot-melt adhesive onto a release layer, drying and preparing a hot-melt adhesive layer.

[0051] Specifically, a hot-melt adhesive coating is applied onto a surface of a 50 μm heavy-duty release film and dried. A coating machine has 7 sections of ovens, 4 meters long for each, with a transfer speed of 12 meter per minute. A first section of oven has a temperature of 70° C., a second section of oven has a temperature of 80° C., a third section of oven has a temperature of 110° C., a fourth section of oven has a temperature of 150° C., a fifth section of oven has a temperature of 150° C., a sixth section of oven has a temperature of 140° C., and a seventh section of oven has a temperature of 100° C. The coating thickness is 65 μm. After exiting the ovens, the heavy-duty release film passes through a cooling roller to cool down and is laminated with a 25 μm release film for winding to obtain a hot-melt adhesive film. Stepwise temperature allows the solvent to evaporate slowly, reducing issues such as pseudo-dry, bubbles, crystal dots, and solvent residue that may affect performance. The hot-melt adhesive coating has the same components as in Embodiment 1.

[0052] Step 2 is, performing UV inkjet printing on the hot-melt adhesive layer to form graphics and obtaining a hot-melt adhesive film with graphics.

[0053] Specifically, the 25 μm release film on the surface of the hot-melt adhesive film is removed. UV inkjet printing is carried out on the hot-melt adhesive film using a UV digital printer. UV ink is selected from Zhuhai Print-Rite New Materials Corporation Limited. An inkjet printing component of the UV digital printer is equipped with a first UV lamp (365-425 nanometers, 25 Watts), which is configured to move synchronously with an inkjet head to instantly cure the printed ink. Then, a PE protective film is applied to obtain a hot-melt adhesive film with graphics.

[0054] Step 3 is, spreading the hot-melt adhesive layer onto a fabric, pressing and obtaining printed fabric with three-dimensional graphics.

[0055] Specifically, the 50 μm heavy-duty release film underneath the hot-melt adhesive film with graphics is removed. The hot-melt adhesive film with graphics is then placed on a cotton fabric. A heat press machine is used to press it at 150° C. for 2 seconds, at a pressure of 0.6 MPa. The PE protective film is then removed, transferring the excess hot-melt adhesive around the graphics to the protective film, while the graphics are completely bonded to the cotton fabric, resulting in a printed fabric with three-dimensional graphics.Performance Testing1. Appearance Characterization

[0056] FIGURE shows a product obtained from Embodiment 1 and the protective film with excess hot-melt adhesive around the graphics. It can be seen that the product has rich and bright colors, with a three-dimensional structure. The edges of the graphics are clear and smooth, with no stringing or excess hot-melt adhesive residue. After tearing off the protective film, the excess hot-melt adhesive around the graphics adheres to the protective film, making waste removal easy. The overall process of the present invention is simple, with a short production cycle, no need for plate making and low preparation costs, and meets the demands for flexible production.2. Color Fastness to Rubbing

[0057] Products from the above embodiments were tested for color fastness to rubbing according to Chinese Standard GB / T 3920-2008. Gray scale assessment used a 5-grade card, where Grade 1 indicates the worst result and Grade 5 indicates the best. Results are shown in Table 1.TABLE 1Dry RubbingWet RubbingEmbodiment 143-4Embodiment 243Embodiment 33-42-3

[0058] The results indicate that the products obtained from the processing method for heat transfer printing fabric with three-dimensional graphics of the present invention have better color fastness to rubbing. Among them, the product from Embodiment 1, which underwent secondary UV irradiation, showed excellent color fastness to rubbing, especially with a significant improvement in color fastness to wet rubbing.

[0059] The above embodiments of the present invention are merely examples provided to clearly illustrate the invention and do not limit the implementation methods of the invention. Ordinary technicians in the field can make other changes or modifications based on the above description. It is neither necessary nor possible to exhaustively list all the implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A processing method of a heat transfer printing fabric based on ultraviolet (UV)-printed three-dimensional graphics, comprising the following steps:step 1, applying a hot-melt adhesive onto a release layer, drying, and preparing a hot-melt adhesive layer;step 2, performing a UV inkjet printing on the hot-melt adhesive layer to form graphics, and laminating a protective layer onto a surface of the hot-melt adhesive layer to obtain a hot-melt adhesive layer with the graphics; andstep 3, removing the release layer from the hot-melt adhesive layer with the graphics, spreading the hot-melt adhesive layer with the graphics onto a fabric, pressing at a temperature of 140-160° C., removing the protective layer and the hot-melt adhesive layer around the graphics, and obtaining the heat transfer printed fabric with the UV-printed three-dimensional graphics.

2. The processing method according to claim 1, wherein during the step 2, a UV irradiation is maintained throughout a process of the UV inkjet printing, with a UV light wavelength ranging from 365-425 nanometers (nm).

3. The processing method according to claim 1, wherein a process of the UV inkjet printing comprises a secondary UV irradiation process, comprising:step 1), a first UV irradiation, wherein a first UV light is configured to move synchronously with inkjet printing components, causing a printed ink to solidify under an irradiation of the first UV light and forming printed graphics; andstep 2), a second UV irradiation, wherein the printed graphics formed in the step 1) is further solidified and finalized under an irradiation of a second UV light.

4. The processing method according to claim 1, wherein during the step 3, a pressing time is 1-10 seconds, and a pressure is 0.1-1 megapascal (MPa).

5. The processing method according to claim 1, wherein the hot-melt adhesive is an ethylene-vinyl acetate copolymer (EVA) hot-melt adhesive or an EVA / thermoplastic polyurethane elastomer (TPU) composite hot-melt adhesive.

6. The processing method according to claim 5, wherein a mass ratio of EVA to TPU in the EVA / TPU composite hot-melt adhesive is (1.4-3):1.

7. The processing method according to claim 5, wherein the EVA / TPU composite hot-melt adhesive comprises the following components in part by mass: 15-25 parts of TPU, 35-45 parts of EVA, 10-14 parts of a tackifier resin, 3-8 parts of a film-forming agent, 1-5 parts of a viscosity modifier, 0.1-3 parts of a hardening resin, 0.1-3 parts of a dispersant, 0.1-3 parts of a humectant, and 0.1-3 parts of a curing agent.

8. The processing method according to claim 6, wherein the EVA / TPU composite hot-melt adhesive comprises the following components in part by mass: 15-25 parts of the TPU, 35-45 parts of the EVA, 10-14 parts of a tackifier resin, 3-8 parts of a film-forming agent, 1-5 parts of a viscosity modifier, 0.1-3 parts of a hardening resin, 0.1-3 parts of a dispersant, 0.1-3 parts of a humectant, and 0.1-3 parts of a curing agent.

9. The processing method according to claim 1, wherein during the step 1, the hot-melt adhesive has a coating thickness of 40-100 micrometers (μm).

10. The processing method according to claim 1, wherein the fabric is at least one of cotton fibers, linen fibers, nylon fibers, acrylic fibers, polyester fibers, or animal furs.

11. A fabric with graphics, wherein the fabric with the graphics is produced by the processing method according to claim 1.

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