Technological method for painting on shoes

Abstract

The invention belongs to the technical field of shoe painting processes, and provides a process method for painting on shoes, which comprises the following steps: (1) vamp pretreatment: activating the surface of a vamp material by adopting plasma treatment equipment; (2) pattern design: generating a digital pattern adaptive to the vamp curved surface through three-dimensional modeling software, and segmenting the digital pattern into a plurality of layers of vector diagram files capable of being overlaid and painted; (3) ink jet control: adopting a piezoelectric ink jet printing head to spray environment-friendly UV curing ink on the vamp layer by layer according to the vector diagram file; (4) curing and shaping: carrying out stepped curing on each layer of ink by using a UV-LED light source; and (5) post-treatment: spraying a transparent wear-resistant coating, and performing hot air curing to form the protective film. According to the method, an activation-jet drawing-curing synergistic system is adopted,-Si-O-bond molecular-level combination is formed by plasma activation and UV ink chemical bonding, and interlayer stress cracks are inhibited through stepped curing.

Description

Technical Field

[0001] The present invention relates to the technical field of shoe spraying processes, and particularly to a spraying process method used for shoes. Background Art

[0002] Traditional upper decoration processes mainly rely on screen printing, heat transfer printing or hand painting, and have the following defects: 1. Poor adaptability: Pattern deformation and color breakage are likely to occur on curved upper surfaces, and it is difficult to achieve complex gradient effects; 2. Environmental protection issues: Solvent-based inks contain VOCs, and harmful gases are generated during the curing process; 3. Low efficiency: Multi-color patterns require multiple plate makings, and the yield rate is low; 4. Insufficient durability: Traditional coatings have poor abrasion resistance, and fading and peeling occur after long-term use. Therefore, there is an urgent need to develop a high-precision and environmentally friendly spraying process method for shoes. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-precision, environmentally friendly spraying process method for shoes to overcome the defects existing in the prior art.

[0004] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a spraying process method for shoes, including the following steps:

[0006] (1) Pretreatment of the upper: Use a plasma treatment device to activate the surface of the upper material, with a treatment power of 200 - 500W and a treatment time of 30 - 90 seconds;

[0007] (2) Pattern design: Generate a digital pattern adapted to the curved surface of the upper through 3D modeling software, and divide it into multiple layers of vector graphic files that can be superposed and sprayed;

[0008] (3) Inkjet control: Use a piezoelectric inkjet print head to spray environmentally friendly UV-curable ink layer by layer on the upper according to the vector graphic file at a resolution of 600 - 1200 dpi, with a spraying thickness of 10 - 50 μm for each layer;

[0009] (4) Curing and shaping: Use a UV-LED light source with a wavelength of 365 - 405 nm to perform stepwise curing on each layer of ink, with an initial curing energy of 100 - 300 mJ / cm 2 , and a final curing energy of 500 - 800 mJ / cm 2 ;

[0010] (5) Post-treatment: Spray a transparent wear-resistant coating and cure it with hot air at 60 - 80 °C to form a protective film.

[0011] Preferably, in the step (1), the gas for plasma treatment is a mixed gas of argon and oxygen, and the mixed volume ratio is 4:1.

[0012] Preferably, in the step (1), the power of the activation treatment is 200-500 W, and the time of the activation treatment is 30-90 s.

[0013] Preferably, in the step (3), the environment-friendly UV-curable ink comprises, by weight percentage: 40-60% of acrylate prepolymer, 3-8% of photoinitiator, 2-5% of nano-silica, 10-20% of pigment dispersion, and 0.5-2% of leveling agent.

[0014] Preferably, in the step (4), the temperature gradient of the stepwise curing is 10-25 °C, 30-50 °C, 55-65 °C, and the heating rate per stage does not exceed 5 °C / min.

[0015] Preferably, in the step (5), the transparent wear-resistant coating is a waterborne polyurethane resin.

[0016] Preferably, in the step (3), the distance between the inkjet print head and the shoe upper has a dynamic adjustment range of 1-5 mm, which is controlled by real-time feedback of a laser ranging sensor.

[0017] Beneficial effects:

[0018] An activation-spraying-curing cooperative system is adopted. Plasma activation and UV ink chemical bonding form a molecular-level bonding of -Si-O- bonds. Stepwise curing can inhibit interlayer stress cracks. Curved surface adaptive spraying is realized through laser ranging and piezoelectric nozzles. And adding nano-SiO2 to the UV-curable ink can enhance the rheological properties of the ink, adapt to high-resolution spraying, and no solvent is added throughout the process from the pretreatment liquid to the protective layer. Specific embodiments

[0019] The present invention provides a spraying process method used on shoes, comprising the following steps:

[0020] (1) Shoe upper pretreatment: The surface of the shoe upper material is activated by using a plasma treatment device;

[0021] (2) Pattern design: A digital pattern adapted to the curved surface of the shoe upper is generated through three-dimensional modeling software and segmented into a multi-layer vector graphic file that can be superimposed and sprayed;

[0022] (3) Inkjet control: A piezoelectric inkjet print head is used to spray the environment-friendly UV-curable ink layer by layer on the shoe upper according to the vector graphic file at a resolution of 600-1200 dpi, and the spraying thickness of each layer is 10-50 μm;

[0023] (4) Curing and shaping: Use a UV-LED light source with a wavelength of 365-405 nm to perform stepwise curing on each layer of ink, and the initial curing energy is 100-300 mJ / cm2 The final curing energy is 500 - 800 mJ / cm 2 ;

[0024] (5) Post - treatment: Spray a transparent wear - resistant coating and cure it with hot air at 60 - 80 °C to form a protective film.

[0025] In the present invention, in the step (1), the gas for plasma treatment is a mixed gas of argon and oxygen, and the mixing volume ratio is 4:1.

[0026] In the present invention, in the step (1), the power of the activation treatment is 200 - 500 W, preferably 250 - 450 W, further preferably 280 - 430 W, and more preferably 300 - 400 W.

[0027] In the present invention, the time of the activation treatment is 30 - 90 S, preferably 40 - 85 S, further preferably 50 - 80 S, and more preferably 60 - 70 S.

[0028] In the present invention, in the step (3), the environment - friendly UV - curable ink comprises, by weight percentage: 40 - 60% of acrylate prepolymer, 3 - 8% of photoinitiator, 2 - 5% of nano - silica, 10 - 20% of pigment dispersion, and 0.5 - 2% of leveling agent.

[0029] In the present invention, the environment - friendly UV - curable ink comprises 40 - 60% of acrylate prepolymer by weight percentage, preferably 43 - 58%, further preferably 45 - 55%, and more preferably 48 - 53%.

[0030] In the present invention, the environment - friendly UV - curable ink comprises 3 - 8% of photoinitiator by weight percentage, preferably 3.5 - 7.5%, further preferably 4 - 7%, and more preferably 4 - 6%.

[0031] In the present invention, the environment - friendly UV - curable ink comprises 2 - 5% of nano - silica by weight percentage, preferably 2.5 - 4.5%, further preferably 3 - 4.3%, and more preferably 3.3 - 4%.

[0032] In the present invention, the environment - friendly UV - curable ink comprises 10 - 20% of pigment dispersion by weight percentage, preferably 11 - 19%, further preferably 13 - 18%, and more preferably 15 - 17%.

[0033] In the present invention, the environment - friendly UV - curable ink comprises 0.5 - 2% of leveling agent by weight percentage, preferably 0.8 - 1.8%, further preferably 1 - 1.5%, and more preferably 1.1 - 1.3%.

[0034] In the present invention, in the step (4), the temperature gradient of stepwise curing is 10 - 25°C, 30 - 50°C, 55 - 65°C, and the heating rate per stage does not exceed 5°C / min.

[0035] In the present invention, in the step (3), the dynamic adjustment range of the distance between the inkjet print head and the shoe upper is 1 - 5 mm, and it is controlled by real-time feedback of a laser distance sensor.

[0036] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0037] Embodiment 1

[0038] An inkjet painting process method used for shoes includes the following steps:

[0039] (1) Pretreatment of the shoe upper: The surface of the shoe upper material is activated by a plasma treatment device; the power of the activation treatment is 210 W, and the time of the activation treatment is 32 s. The gas for plasma treatment is a mixed gas of argon and oxygen, and the mixed volume ratio is 4:1.

[0040] (2) Pattern design: A digital pattern adapted to the curved surface of the shoe upper is generated through 3D modeling software and divided into multiple layers of vector graphic files that can be superposed and inkjet printed;

[0041] (3) Inkjet control: A piezoelectric inkjet print head is used to spray environmentally friendly UV-curable ink layer by layer on the shoe upper according to the vector graphic file at a resolution of 600 - 1200 dpi, and the spraying thickness of each layer is 10 - 50 μm;

[0042] The environmentally friendly UV-curable ink includes by weight percentage: 40% acrylate prepolymer, 4% photoinitiator, 3% nano-silica, 12% pigment dispersion, 0.8% leveling agent.

[0043] The dynamic adjustment range of the distance between the inkjet print head and the shoe upper is 1 mm, and the color fastness (GB / T 3920) of the pattern on the surface of the shoe upper is ≥ 4 levels, and the weight loss of abrasion resistance (Taber test) is ≤ 20 mg / 1000 revolutions, which is controlled by real-time feedback of a laser distance sensor.

[0044] (4) Curing and shaping: A UV-LED light source with a wavelength of 365 nm is used to perform stepwise curing on each layer of ink, with an initial curing energy of 100 mJ / cm 2 , and a final curing energy of 500 mJ / cm 2 ; in the step (4), the temperature gradient of stepwise curing is 10°C, 30°C, 55°C, and the heating rate per stage does not exceed 5°C / min.

[0045] (5) Post-treatment: Spray a transparent wear-resistant coating and cure it with hot air at 60 °C to form a protective film. The transparent wear-resistant coating is a waterborne polyurethane resin. After curing, the film thickness is 5-15 μm and the pencil hardness is ≥3H.

[0046] Example 2

[0047] A spray painting process method used on shoes, comprising the following steps:

[0048] (1) Pretreatment of the shoe upper: Use a plasma treatment device to activate the surface of the shoe upper material; the power of the activation treatment is 300 W and the time of the activation treatment is 50 s.

[0049] In step (1), the gas for plasma treatment is a mixed gas of argon and oxygen, and the mixing volume ratio is 4:1.

[0050] (2) Pattern design: Generate a digital pattern adapted to the curved surface of the shoe upper through 3D modeling software and divide it into multiple layers of vector graphic files that can be superimposed and spray painted;

[0051] (3) Inkjet control: Use a piezoelectric inkjet print head to spray environmentally friendly UV-curable ink layer by layer on the shoe upper according to the vector graphic file at a resolution of 600-1200 dpi, and the spraying thickness of each layer is 10-50 μm;

[0052] The environmentally friendly UV-curable ink includes, by weight percentage: 51% acrylate prepolymer, 5% photoinitiator, 3% nano-silica, 15% pigment dispersion, 1.2% leveling agent.

[0053] The dynamic adjustment range of the distance between the empty inkjet print head and the shoe upper is 3 mm. The color fastness (GB / T 3920) of the pattern on the shoe upper surface is ≥4 levels by real-time feedback control of the laser distance sensor, and the weight loss of abrasion resistance (Taber test) is ≤20 mg / 1000 revolutions.

[0054] (4) Curing and shaping: Use a UV-LED light source with a wavelength of 380 nm to perform stepwise curing on each layer of ink. The initial curing energy is 200 mJ / cm 2 , and the final curing energy is 600 mJ / cm 2 ; the temperature gradient of stepwise curing is 15 °C, 40 °C, 60 °C, and the heating rate per stage does not exceed 5 °C / min.

[0055] (5) Post-treatment: Spray a transparent wear-resistant coating and cure it with hot air at 70 °C to form a protective film. The transparent wear-resistant coating is a waterborne polyurethane resin. After curing, the film thickness is 5-15 μm and the pencil hardness is ≥3H.

[0056] Example 3

[0057] A spray painting process method used on shoes, comprising the following steps:

[0058] (1) Pre-treatment of shoe upper: Activate the surface of the shoe upper material using a plasma treatment device; the power of the activation treatment is 500W, and the time of the activation treatment is 90S.

[0059] In step (1), the gas for plasma treatment is a mixed gas of argon and oxygen, and the mixed volume ratio is 4:1.

[0060] (2) Pattern design: Generate a digital pattern adapted to the shoe upper surface through 3D modeling software and divide it into multiple layers of vector graphic files that can be superimposed and spray-painted;

[0061] (3) Inkjet control: Use a piezoelectric inkjet print head to spray environmentally friendly UV-curable ink layer by layer on the shoe upper according to the vector graphic files at a resolution of 600 - 1200 dpi, and the spraying thickness of each layer is 10 - 50μm;

[0062] The environmentally friendly UV-curable ink includes, by weight percentage: 60% acrylate prepolymer, 8% photoinitiator, 5% nano-silica, 20% pigment dispersion, 2% leveling agent.

[0063] The dynamic adjustment range of the distance between the inkjet print head and the shoe upper is 5mm, and the color fastness (GB / T 3920) of the pattern on the shoe upper surface is ≥4 levels by real-time feedback control of a laser ranging sensor, and the weight loss of abrasion resistance (Taber test) is ≤20mg / 1000 revolutions.

[0064] (4) Curing and shaping: Use a UV-LED light source with a wavelength of 405nm to perform stepwise curing on each layer of ink, with an initial curing energy of 300mJ / cm 2 , and a final curing energy of 800mJ / cm 2 ; the temperature gradient for stepwise curing is 25℃, 50℃, 65℃, and the heating rate per stage does not exceed 5℃ / min.

[0065] (5) Post-treatment: Spray a transparent wear-resistant coating and cure it with hot air at 80℃ to form a protective film. The transparent wear-resistant coating is a water-based polyurethane resin, and the film thickness after curing is 5 - 15μm, and the pencil hardness ≥3H.

[0066] Performance test:

[0067] Table 1

[0068] Project Color fastness Wear resistance Film thickness Pencil hardness Example 1 ≥ Grade 4 No peeling off after 1000 times 5μm ≥3H Example 2 ≥ Grade 4 No peeling off after 1000 times 10μm ≥3H Example 3 ≥ Grade 4 No peeling off after 1000 times 15μm ≥3H

[0069] As can be seen from the above embodiments, the present invention provides a method for spraying on shoes, which adopts an activation-spraying-curing synergistic system, plasma activation and UV ink chemical bonding to form -Si-O-bond molecular level combination, and interlayer stress cracks can be suppressed through step curing. Adaptive spraying of curved surfaces is achieved through laser ranging and piezoelectric nozzles, and nano-SiO2 is added to UV curing ink to enhance the rheological properties of the ink, adapt to high-resolution spraying, and no solvent is added from the pretreatment liquid to the protective layer.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A spray painting process method used on shoes, characterized in that, It includes the following steps: (1) Upper surface pretreatment: Activate the surface of the upper material using a plasma treatment device; (2) Pattern design: Generate a digital pattern adapted to the curved surface of the upper through 3D modeling software and divide it into multi-layer vector graphic files that can be superimposed and sprayed; (3) Inkjet control: Use a piezoelectric inkjet print head to spray environmentally friendly UV-curable ink layer by layer on the upper according to the vector graphic files at a resolution of 600 - 1200 dpi, and the spraying thickness of each layer is 10 - 50 μm; (4) Curing and shaping: Use a UV-LED light source with a wavelength of 365 - 405 nm to step-cure each layer of ink. The initial curing energy is 100 - 300 mJ / cm 2 , and the final curing energy is 500 - 800 mJ / cm 2 ; (5) Post-treatment: Spray a transparent wear-resistant coating and cure it with hot air at 60 - 80 °C to form a protective film.

2. The method according to claim 1, wherein: In the step (1), the gas for plasma treatment is a mixed gas of argon and oxygen, and the mixing volume ratio is 4:

1.

3. The method according to claim 2, characterized in that, In the step (1), the power of the activation treatment is 200 - 500 W, and the time of the activation treatment is 30 - 90 S.

4. The method according to claim 1, wherein: In the step (3), the environmentally friendly UV-curable ink includes, by weight percentage: 40 - 60% acrylate prepolymer, 3 - 8% photoinitiator, 2 - 5% nano-silica, 10 - 20% pigment dispersion, 0.5 - 2% leveling agent.

5. The method according to claim 1, wherein: In the step (4), the temperature gradient for stepwise curing is 10 - 25 °C, 30 - 50 °C, 55 - 65 °C, and the heating rate in each stage does not exceed 5 °C / min.

6. The method according to claim 5, wherein: In the step (5), the transparent wear-resistant coating is a waterborne polyurethane resin.

7. The method according to any one of claims 1-6, characterized in that: In the step (3), the dynamic adjustment range of the distance between the inkjet print head and the upper is 1 - 5 mm, which is controlled by real-time feedback of a laser distance sensor.