Rubber tube code spraying method based on multilayer UV curing ink

Abstract

The invention discloses a rubber tube code spraying method based on multilayer UV curing ink, and belongs to the technical field of rubber tube processing, and the method comprises the following steps: sequentially spraying a UV primer layer, a UV white ink identification layer and a UV protection layer on the surface of the outer wall of a rubber tube, and sequentially overlapping the UV primer layer, the UV white ink identification layer and the UV protection layer to form a rubber tube code spraying layer; wherein the UV primer layer and the UV protective layer are transparent adhesive layers; the UV primer forming the UV primer layer takes polyurethane acrylate containing isocyanate as a main resin component; uV white ink identification ink for forming the UV white ink identification layer takes epoxy acrylate resin as a main resin component; and the UV protection glue forming the UV protection layer takes amino-terminated fluorine-containing prepolymer modified acrylate resin as a main resin component. The marking layer can be firmly attached to the outer wall of the rubber pipe and is not prone to being affected by external factors (abrasion, corrosion, moisture and the like), and compared with the prior art, the marking layer is not prone to falling, color fading, blurring and the like in the machining or using process.

Description

Technical Field

[0001] This invention belongs to the field of hose processing technology and relates to a hose inkjet printing method based on multilayer UV-curable ink. Background Technology

[0002] The markings on hoses mainly serve to provide safety warnings, functional identification, and standardized management, ensuring that they can be used correctly and safely in various application scenarios. Hose markings include numbers, letters, words, symbols, and patterns.

[0003] Existing hose markings are generally obtained by inkjet printers on the outer surface of the hose. The processing speed is fast, but the markings are only a single layer attached to the outer wall of the hose. Not only are defects such as discoloration, blurring, and peeling prone to occur during the hose processing, vulcanization, and cleaning, but also during the long-term use of the hose, it is affected by external environmental wear, moisture, and chemical corrosion, which can also lead to defects such as discoloration, blurring, and peeling. Summary of the Invention

[0004] The purpose of this invention is to provide a method for marking rubber tubes based on multilayer UV-curable ink, which solves the problem that the markings on the surface of rubber tubes are prone to peeling off, blurring, or discoloration during processing or use.

[0005] The technical solution adopted in this invention is as follows: A method for marking rubber tubes based on multilayer UV-curable ink includes the following steps: sequentially spraying a UV primer layer, a UV white ink marking layer, and a UV protective layer onto the outer surface of the rubber tube; the UV primer layer, UV white ink marking layer, and UV protective layer are sequentially stacked to form a rubber tube marking layer; wherein, the UV primer layer and the UV protective layer are both transparent adhesive layers. The UV primer forming the UV base coat is mainly composed of isocyanate-containing polyurethane acrylate resin; the UV white ink marking ink forming the UV white ink marking layer is mainly composed of epoxy acrylate resin; and the UV protective adhesive forming the UV protective layer is mainly composed of amino-terminated fluorinated prepolymer modified acrylate resin.

[0006] Further, the UV primer comprises the following components in parts by weight: 100 parts of isocyanate-containing polyurethane acrylate, 5-7 parts of trimethylolpropane triacrylate, 10-12 parts of dipentaerythritol hexaacrylate, 3-5 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-2 parts of isocyanate end-capping agent, 2-3 parts of organosilicon coupling agent KH-550, 0.5-1 part of leveling agent, and 0.3-0.5 parts of fumed silica.

[0007] Furthermore, the UV white ink marking ink comprises the following components in parts by weight: 55 parts epoxy acrylate resin, 10-15 parts 1,6-hexanediol diacrylate, 8-12 parts neopentyl glycol polymethyl ethylene oxide diacrylate, 20-25 parts titanium dioxide, 2-4 parts photoinitiator TPO, 2-3 parts ethyl aminopropionate, 1-2 parts dispersant BYK-110, and 0.3-0.5 parts defoamer BYK-088.

[0008] Furthermore, the UV protective adhesive comprises the following components in parts by weight: 60 parts of amino-terminated fluorinated prepolymer modified acrylate resin, 5-8 parts of polymethyl methacrylate, 2-3 parts of 3-aminopropyltriethoxysilane, 8-12 parts of pentaerythritol tetraacrylate, 2-4 parts of photoinitiator BAPO, 1-2 parts of nano silica, and 0.5-1 part of UV absorber UV-531.

[0009] Furthermore, the leveling agent is leveling agent BYK-333.

[0010] Furthermore, the isocyanate capping agent is butanone oxime.

[0011] The aforementioned tube marking method based on multilayer UV-curable ink includes the following specific steps: S1. Use a glue sprayer to evenly spray UV primer onto the outer surface of the glue tube, controlling the wet film thickness to 8-12μm; after spraying, place the glue tube into a heating chamber to heat the primer layer to 130-135℃ and hold for 20-30 minutes; then place the glue tube under a UV curing device for UV irradiation, with a UV wavelength of 365nm and a light intensity of 100mW / cm². 2 The light exposure time is 3-5 seconds, forming a transparent base layer; S2. Use a small character inkjet printer to precisely spray UV white ink onto the base layer to form a label layer with a preset pattern or text; immediately after spraying, send the tube into a UV curing device for UV irradiation. The UV wavelength is 365nm and the irradiation intensity is 120mW / cm². 2 The light exposure time is 4-6 seconds, forming a UV white ink marking layer; S3. Use a spray gun to evenly spray UV protective adhesive onto the UV white ink marking layer, controlling the wet film thickness to 10-15μm. After spraying, send the tube into a UV curing device for full UV irradiation. The UV wavelength is 365nm, the light intensity is 150mW / cm², and the irradiation time is 8-12s, so that the UV base layer, UV white ink marking layer, and UV protective layer are completely cured and cross-linked to form an integrated structure, ultimately forming the tube coding layer.

[0012] Further, the preparation method of the UV primer includes the following steps: isocyanate-containing polyurethane acrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate are sequentially added to a stirred tank and stirred and mixed under a nitrogen protective atmosphere, with the mixing temperature controlled at 40-50℃; 2-hydroxy-2-methyl-1-phenyl-1-propanone is added to the stirred tank, and stirring is continued for 15-20 minutes, maintaining the temperature at 40-50℃; the temperature inside the stirred tank is lowered to 25-30℃, and isocyanate end-capping agent butanone oxime and organosilicon coupling agent KH-550 are added sequentially, and stirred evenly; finally, leveling agent BYK-333 and fumed silica are added, and the mixture is dispersed at high speed. After dispersion, the mixture is filtered through a 200-300 mesh filter to remove impurities and undispersed particles, obtaining the UV primer.

[0013] Further, the preparation method of the UV white ink marking ink includes the following steps: adding epoxy acrylate resin, 1,6-hexanediol diacrylate, and neopentyl glycol polymethyl ethylene oxide diacrylate into a dispersion vessel, stirring and mixing evenly, and controlling the mixing temperature at 30-40℃ to obtain a resin mixture; adding dispersant BYK-110 to the resin mixture, stirring for 5-10 minutes, and then gradually adding titanium dioxide while stirring; after the titanium dioxide is added, dispersing at high speed, and controlling the dispersion temperature at 35-45℃; sending the dispersed mixture into a sand mill for grinding, returning the ground mixture to the dispersion vessel, adding photoinitiator TPO, ethyl aminopropionate, and defoamer BYK-088, stirring and mixing, and filtering through a 300-400 mesh filter to obtain the UV white ink marking ink.

[0014] Further, the preparation method of the UV protective adhesive includes the following steps: adding amino-terminated fluorinated prepolymer modified acrylate resin, polymethyl methacrylate, and pentaerythritol tetraacrylate into a stirred tank and stirring and mixing at a temperature of 30-40°C; after stirring and mixing evenly, adding 3-aminopropyltriethoxysilane into the stirred tank, maintaining the temperature at 30-40°C, continuing to stir evenly, adding photoinitiator BAPO and ultraviolet absorber UV-531, stirring for 10-15 minutes, and then adding nano-silica and dispersing at high speed; filtering the dispersed mixture through a 200-300 mesh filter to remove impurities and agglomerated nanoparticles to obtain the UV protective adhesive.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention discloses a tube marking method based on multilayer UV-curable ink, which adopts a "sandwich" structure to sandwich the marking layer between the base adhesive layer and the protective layer. The base adhesive layer strengthens the adhesion between the marking layer and the outer wall surface of the tube, and the protective layer provides outer protection for the marking layer. The synergistic effect of the base adhesive layer and the protective layer enables the marking layer to adhere firmly to the outer wall surface of the tube and is not easily affected by external factors (wear, corrosion, moisture, etc.). Compared with the prior art, it is less likely to fall off, fade, or become blurred during processing or use. 2. Based on a multi-layer adhesive layer, this invention strengthens the interlayer bonding strength of the base layer, labeling layer, and protective layer by using isocyanate-containing polyurethane acrylate, epoxy acrylate resin, and amino-terminated fluorinated prepolymer-modified acrylate resin as the main resin components of the base layer, labeling layer, and protective layer, respectively. Chemical bonds are formed between the isocyanate, epoxy groups, and amino groups, thereby enhancing the interlayer bonding strength of the base layer, labeling layer, and protective layer. Furthermore, based on the photocuring mechanism of acrylate, the three adhesive layers can be simultaneously cross-linked and cured under ultraviolet light, simplifying the operation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart of a tube marking method based on multilayer UV-curable ink; Figure 2 This is a product image of inkjet printing within the scope of Embodiment 2 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0021] Example 1 like Figure 1 As shown, a preferred embodiment of the present invention provides a tube marking method based on multilayer UV-curable ink, comprising the following steps: S1. Using a spray gun, evenly spray UV primer onto the outer surface of the adhesive tube. The spraying pressure is 0.3-0.5 MPa, the spraying distance is 15-20 cm, and the wet film thickness is controlled at 8-12 μm. After spraying, place the adhesive tube into a heating chamber to heat the primer layer to 130-135℃ and hold for 20-30 minutes. Then, place the adhesive tube under a UV curing device for UV irradiation. The UV wavelength is 365 nm, and the light intensity is 100 mW / cm². 2 The light exposure time is 3-5 seconds, allowing the base coat to reach about 50% curing, forming a transparent base coat. S2. Use a small character inkjet printer to precisely spray UV white ink marking ink onto the base layer at a speed of 2-3 m / s to form a marking layer with a preset pattern or text. After spraying, immediately send the tube into a UV curing device for UV irradiation. The UV wavelength is 365nm and the light intensity is 120mW / cm². 2 The light exposure time is 4-6 seconds, which allows the white ink labeling layer to reach about 50% curing degree, forming a UV white ink labeling layer; S3. Use a spray gun to evenly spray UV protective adhesive onto the UV white ink marking layer. The spraying pressure is 0.4-0.6MPa, the spraying distance is 15-20cm, and the wet film thickness is controlled at 10-15μm. After spraying, send the tube into a UV curing device for full UV irradiation. The UV wavelength is 365nm, the light intensity is 150mW / cm², and the irradiation time is 8-12s. This will allow the UV base layer, UV white ink marking layer, and UV protective layer to fully cure and cross-link to form an integrated structure, ultimately forming the tube coding layer.

[0022] The UV primer comprises the following components in parts by weight: 100 parts isocyanate-containing polyurethane acrylate, 5 parts trimethylolpropane triacrylate, 10 parts dipentaerythritol hexaacrylate, 3 parts 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1 part isocyanate end-capping agent, 2 parts organosilicon coupling agent KH-550, 0.5 parts leveling agent, and 0.3 parts fumed silica.

[0023] The UV white ink marking ink comprises the following components in parts by weight: 55 parts epoxy acrylate resin, 10 parts 1,6-hexanediol diacrylate, 8 parts neopentyl glycol polymethyl ethylene oxide diacrylate, 20 parts titanium dioxide, 2 parts photoinitiator TPO, 2 parts ethyl aminopropionate, 1 part dispersant BYK-110, and 0.3 parts defoamer BYK-088.

[0024] The UV protective adhesive comprises the following components in parts by weight: 60 parts amino-terminated fluorinated prepolymer modified acrylate resin, 5 parts polymethyl methacrylate, 2 parts 3-aminopropyltriethoxysilane, 8 parts pentaerythritol tetraacrylate, 2 parts photoinitiator BAPO, 1 part nano silica, and 0.5 parts UV absorber UV-531.

[0025] The leveling agent is BYK-333.

[0026] The isocyanate capping agent is methyl ethyl ketone oxime.

[0027] The preparation method of the UV primer includes the following steps: Isocyanate-containing polyurethane acrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate are sequentially added to a stirred tank. Under a nitrogen protective atmosphere, the mixture is stirred at 800 r / min for 30 min, with the mixing temperature controlled at 50℃. 2-hydroxy-2-methyl-1-phenyl-1-propanone is added to the stirred tank, and stirring continues at 1000 r / min for 15 min, maintaining the temperature at 50℃. The temperature inside the stirred tank is lowered to 30℃, and isocyanate end-capping agent butanone oxime and organosilicon coupling agent KH-550 are added sequentially. The mixture is stirred at 800 r / min for 20 min. Finally, leveling agent BYK-333 and fumed silica are added, and the mixture is dispersed at 1200 r / min for 35 min. After dispersion, the mixture is filtered through a 200-300 mesh filter to remove impurities and undispersed particles, yielding the UV primer.

[0028] The preparation method of the UV white ink marking ink includes the following steps: epoxy acrylate resin, 1,6-hexanediol diacrylate, and neopentyl glycol polymethyl ethylene oxide diacrylate are added to a dispersion vessel and stirred at 600-800 r / min for 15-20 min, with the mixing temperature controlled at 40℃, to obtain a resin mixture; dispersant BYK-110 is added to the resin mixture, and after stirring for 5-10 min, titanium dioxide is gradually added while stirring. After the titanium dioxide is added, the mixture is stirred at 1500 r / min. The mixture was dispersed at high speed for 60 minutes at a rotation speed of 2500 r / min, with the dispersion temperature controlled at 45℃. The dispersed mixture was then sent to a sand mill for grinding, with zirconia beads as the grinding media. The grinding speed was 2500 r / min, and the grinding time was 2.5 h. The ground mixture was then returned to the dispersion vessel, and photoinitiator TPO, ethyl aminopropionate, and defoamer BYK-088 were added. The mixture was stirred at 1000 r / min for 20 minutes. After stirring, the mixture was filtered through a 300-400 mesh filter to obtain UV white ink marking ink.

[0029] The preparation method of the UV protective adhesive includes the following steps: amino-terminated fluorinated prepolymer modified acrylate resin, polymethyl methacrylate, and pentaerythritol tetraacrylate are added to a stirred tank and stirred at 1000 r / min for 30 min at 40°C; 3-aminopropyltriethoxysilane is added to the stirred tank, the temperature is maintained at 40°C, and stirring is continued at 1000 r / min for 20 min; then photoinitiator BAPO and UV absorber UV-531 are added, and stirring is continued for 15 min; then nano-silica is added, and high-speed dispersion is carried out at 11500 r / min for 30 min; the dispersed mixture is filtered through a 200-300 mesh filter to remove impurities and agglomerated nanoparticles, thus obtaining the UV protective adhesive.

[0030] The preparation method of isocyanate-containing polyurethane acrylate is as follows: Prepare 40 parts of isophorone diisocyanate, 25 parts of hydroxypropyl acrylate, 0.05 parts of dibutyltin dilaurate, 0.12 parts of hydroquinone, and 20 parts of anhydrous ethyl acetate; in a nitrogen-protected four-necked reactor, add isophorone diisocyanate and anhydrous ethyl acetate, stir and heat to 50°C, add hydroxypropyl acrylate dropwise at a rate of 1-2 drops / second, and keep the mixture at this temperature and stir for 2.5-3 hours. During this period, monitor the free -NCO content in the reaction system by di-n-butylamine titration until the free -NCO content drops to 4.0-4.5%. Add hydroquinone to the reaction system, continue stirring at this temperature for 0.5 hours, cool the reaction system to room temperature, and remove the anhydrous ethyl acetate by vacuum distillation to obtain isocyanate-containing polyurethane acrylate. The free -NCO content of this resin is stable at 4.0-4.5%.

[0031] The preparation method of fluorinated prepolymer-modified acrylate resin with terminal amino groups is as follows: using fluorinated acrylate monomer (perfluorooctyl ethyl acrylate) and butyl acrylate (mass ratio of 1:5) as comonomers and azobisisobutyronitrile (AIBN) as initiator, the copolymerization reaction is carried out in ethyl acetate solvent at 70°C for 4-6 hours to obtain a fluorinated prepolymer; amino groups are introduced at the end of the prepolymer molecular chain through an aminolysis reaction (ethylenediamine aminolysis) to obtain a fluorinated prepolymer with terminal amino groups; the fluorinated prepolymer with terminal amino groups is mixed with acrylate resin (methyl methacrylate-butyl acrylate copolymer) at a mass ratio of 1:10, xylene solvent is added, and the mixture is stirred and reacted at 85°C for 3-4 hours. The solvent is removed by vacuum distillation, and the mixture is cooled to room temperature to obtain fluorinated prepolymer-modified acrylate resin with terminal amino groups.

[0032] Example 2

[0033] Based on Example 1, the UV primer in this embodiment comprises the following components in parts by weight: 100 parts of isocyanate-containing polyurethane acrylate, 6 parts of trimethylolpropane triacrylate, 11 parts of dipentaerythritol hexaacrylate, 4 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1.5 parts of isocyanate end-capping agent, 3 parts of organosilicon coupling agent KH-550, 0.8 parts of leveling agent, and 0.4 parts of fumed silica.

[0034] The UV white ink marking ink comprises the following components in parts by weight: 55 parts epoxy acrylate resin, 13 parts 1,6-hexanediol diacrylate, 10 parts neopentyl glycol polymethyl ethylene oxide diacrylate, 23 parts titanium dioxide, 3 parts photoinitiator TPO, 3 parts ethyl aminopropionate, 2 parts dispersant BYK-110, and 0.4 parts defoamer BYK-088.

[0035] The UV protective adhesive comprises the following components in parts by weight: 60 parts of amino-terminated fluorinated prepolymer modified acrylate resin, 7 parts of polymethyl methacrylate, 3 parts of 3-aminopropyltriethoxysilane, 10 parts of pentaerythritol tetraacrylate, 3 parts of photoinitiator BAPO, 2 parts of nano-silica, and 0.8 parts of UV absorber UV-531. The remaining components are the same as in Example 1. The preparation methods for the UV primer, UV white ink marking ink, and UV protective adhesive are adjusted slightly according to Example 1. A sample image of the product printed in this example is shown below. Figure 2 As shown.

[0036] Example 3

[0037] Based on Example 1, the UV primer in this embodiment comprises the following components in parts by weight: 100 parts of isocyanate-containing polyurethane acrylate, 7 parts of trimethylolpropane triacrylate, 12 parts of dipentaerythritol hexaacrylate, 5 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2 parts of isocyanate end-capping agent, 3 parts of organosilicon coupling agent KH-550, 1 part of leveling agent, and 0.5 parts of fumed silica.

[0038] The UV white ink marking ink comprises the following components in parts by weight: 55 parts epoxy acrylate resin, 15 parts 1,6-hexanediol diacrylate, 12 parts neopentyl glycol polymethyl ethylene oxide diacrylate, 25 parts titanium dioxide, 4 parts photoinitiator TPO, 3 parts ethyl aminopropionate, 2 parts dispersant BYK-110, and 0.5 parts defoamer BYK-088.

[0039] The UV protective adhesive comprises the following components in parts by weight: 60 parts of amino-terminated fluorinated prepolymer modified acrylate resin, 8 parts of polymethyl methacrylate, 3 parts of 3-aminopropyltriethoxysilane, 12 parts of pentaerythritol tetraacrylate, 4 parts of photoinitiator BAPO, 2 parts of nano-silica, and 1 part of UV absorber UV-531. The remaining components are the same as in Example 1, with minor adjustments made to the preparation methods of the UV primer, UV white ink marking ink, and UV protective adhesive.

[0040] Comparative Example 1 Based on Example 2, but differing from Example 2, this comparative example provides a method for marking rubber tubes using multi-layer UV-curable ink without applying a primer and protective adhesive. The marking layer is directly printed, comprising the following steps: using a small character inkjet printer to precisely spray UV white ink marking ink onto the outer wall of the rubber tube at a speed of 2-3 m / s, forming a marking layer with a preset pattern or text; immediately after spraying, the rubber tube is placed in a UV curing device for UV irradiation, with a wavelength of 365 nm and an irradiation intensity of 120 mW / cm². 2The light exposure time is 20 seconds to allow the white ink marking layer to fully cure, forming a UV white ink marking layer. The components and preparation method of the sprayed UV white ink marking ink are described in Example 2.

[0041] Comparative Example 2 Based on Example 2, unlike Example 2, this comparative example provides a tube coding method based on multilayer UV-curable ink that does not spray a UV primer, and includes the following steps: S1. Use a small character inkjet printer to precisely spray UV white ink marking ink onto the outer wall of the tubing at a speed of 2-3 m / s, forming a marking layer with a preset pattern or text. After spraying, immediately place the tubing into a UV curing device for UV irradiation. The UV wavelength is 365nm, and the irradiation intensity is 120mW / cm². 2 The light exposure time is 4-6 seconds, which allows the white ink labeling layer to reach about 50% curing degree, forming a UV white ink labeling layer; S2. Use a spray gun to evenly spray UV protective adhesive onto the UV white ink marking layer. The spraying pressure is 0.4-0.6MPa, the spraying distance is 15-20cm, and the wet film thickness is controlled at 10-15μm. After spraying, send the tube into a UV curing device for full UV irradiation. The UV wavelength is 365nm, the light intensity is 150mW / cm², and the irradiation time is 8-12s, so that the UV white ink marking layer and UV protective layer are completely cured and cross-linked to form an integrated structure, ultimately forming the tube coding layer.

[0042] Comparative Example 3 Based on Example 2, unlike Example 2, this comparative example provides a tube coding method based on multilayer UV-curable ink that does not spray a protective adhesive, and includes the following steps: S1. Use a spray gun to evenly spray UV primer onto the outer wall of the adhesive tube. The spraying pressure is 0.3-0.5 MPa, the spraying distance is 15-20 cm, and the wet film thickness is controlled at 8-12 μm. After spraying, place the adhesive tube into a heating chamber to heat the primer layer to 130-135℃ and hold for 20-30 minutes. Then place the adhesive tube under a UV curing device for UV irradiation. The UV wavelength is 365 nm, and the light intensity is 100 mW / cm². 2 The light exposure time is 3-5 seconds, allowing the base coat to reach about 50% curing, forming a transparent base coat. S2. Use a small character inkjet printer to precisely spray UV white ink marking ink onto the base layer at a speed of 2-3 m / s to form a marking layer with a preset pattern or text. After spraying, immediately send the tube into a UV curing device for UV irradiation. The UV wavelength is 365nm and the light intensity is 120mW / cm². 2The light exposure time is 18-20 seconds, which allows the UV base adhesive layer and UV white ink marking layer to be fully cured and cross-linked to form an integrated structure, ultimately forming the tube coding layer.

[0043] Comparative Example 4 Based on Example 2, the difference from Example 2 is that the UV primer in this comparative example uses isocyanate-free polyurethane acrylate (model 230A2 polyurethane acrylate), and the UV primer in this comparative example also does not contain isocyanate end-capping agent. The rest of the components are the same as in Example 2.

[0044] Comparative Example 5 Based on Example 2, the difference is that the fluorinated prepolymer-modified acrylate resin in this comparative UV protective adhesive does not contain terminal amino groups. The preparation method is as follows: using fluorinated acrylate monomers (perfluorooctyl ethyl acrylate) and butyl acrylate (mass ratio 1:5) as comonomers, and azobisisobutyronitrile (AIBN) as an initiator, the copolymerization reaction is carried out in ethyl acetate solvent at 70°C for 4-6 hours to obtain a fluorinated prepolymer; the fluorinated prepolymer is then mixed with acrylate resin (methyl methacrylate-butyl acrylate copolymer) at a mass ratio of 1:10, xylene solvent is added, and the mixture is stirred and reacted at 85°C for 3-4 hours. The solvent is removed by vacuum distillation, and the mixture is cooled to room temperature to obtain the fluorinated prepolymer-modified acrylate resin. The remaining parts are consistent with Example 2.

[0045] Experimental Example 1 The appearance characteristics, abrasion resistance, corrosion resistance, and weather resistance of the hose markings prepared in Examples 1-3 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0046] Appearance feature inspection: Visual observation combined with 50x magnification is used, referring to the standard GB / T 9761-2008 "Visual colorimetric comparison of paints and varnishes". The inspection content includes whether the inkjet printing layer is flat and smooth, without bubbles, without cracks, etc., and the clarity of the marking (no jagged edges on the text, complete pattern). Abrasion resistance testing: Referring to Method 2 of GB / T 7424.2-2008 for abrasion resistance testing, adjustments were made to the method for the rubber tube. Rubber tubes from Examples 1-3 and Comparative Examples 1-5 that had undergone inkjet printing were selected, and samples with a length of 750 mm were cut to ensure the inkjet marking area was intact and free from initial damage. Three samples were prepared in parallel for each sample. The test environment was a temperature of 23℃±2℃ and a relative humidity of 50%±5%. Two pieces of white wool felt (5 mm thick) were completely soaked in distilled water, and excess water was squeezed out (until no dripping). The rubber tube sample was horizontally fixed on the support plate of the test device, with the inkjet marking layer facing upwards, between the two soaked wool felt pieces (the upper wool felt was tightly adhered to the inkjet layer). A nominal force of 10 N was applied to the wool felt, and the device was started to move the wool felt along the longitudinal axis of the rubber tube by 100 mm. The sample was moved back and forth within the stroke, and the number of rubbing cycles was set to 500 (one reciprocation is one cycle, frequency 30 times / minute). After the test, the sample was removed, and the surface moisture of the inkjet area was gently wiped with a clean soft cloth. After air drying for 30 minutes, the sample was tested to observe whether the inkjet layer faded or exposed the base layer. At the same time, a grayscale meter was used to measure the change rate of the grayscale value of the mark before and after friction (grayscale value change rate = |grayscale value after friction - grayscale value before friction| / grayscale value before friction × 100%). A change rate ≤ 5% is considered qualified, and there should be no obvious change visible to the naked eye. Corrosion resistance testing: acid resistance, alkali resistance, and oil resistance tests were conducted respectively, referring to standard GB / T 1763-1979 "Determination of Chemical Resistance of Coatings"; Acid resistance test: Immerse the sample in a 5% (mass fraction) hydrochloric acid solution at 25°C for 24 hours. After immersion, rinse with distilled water and air dry. Observe whether the coding layer is bubbling, peeling, fading or other abnormalities. Alkali resistance test: Immerse the sample in a 5% (mass fraction) sodium hydroxide solution at 25°C for 24 hours. After immersion, rinse with distilled water and air dry. Observe whether the coding layer is bubbling, peeling, fading or other abnormalities. Oil resistance test: Immerse the sample in engine oil at 40℃ for 24 hours. After immersion, wipe the surface oil with anhydrous ethanol and observe whether the inkjet printing layer has any abnormalities such as bubbling, peeling, or fading. Weather resistance testing: Xenon lamp aging test was conducted, referring to standard GB / T 1865-2009 "Artificial weathering and artificial radiation exposure of paints and varnishes - filtered xenon arc radiation". Test conditions: irradiance 1.5 W / (m²). 2 After continuous irradiation at 65℃ and 50% relative humidity for 1000 hours, observe whether the inkjet printing layer yellows, cracks, or peels off. At the same time, measure the yellowing index (ΔYI). ΔYI≤2 is excellent, ≤5 is qualified, and >5 is unqualified.

[0047] Table 1 Performance test results of hose markings Apparent features abrasion resistance Acid resistance Alkali resistance Oil-resistant Weather resistance Example 1 The inkjet printing layer is free of defects and the markings are clear. The coding layer showed no abnormalities, and the grayscale value variation rate was 1-2%. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer shows no abnormalities, and ΔYI < 2. Example 2 The inkjet printing layer is free of defects and the markings are clear. The inkjet printing layer showed no abnormalities, and the grayscale value change rate of the markings was less than 1%. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. No abnormalities were found in the inkjet printing layer ΔYI < 1 Example 3 The inkjet printing layer is free of defects and the markings are clear. The inkjet printing layer showed no abnormalities, and the grayscale value variation rate was 1-2%. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer shows no abnormalities, and ΔYI < 2. Comparative Example 1 The inkjet printing layer has air bubbles and the marking edges are jagged. The inkjet printing layer is exposed, the markings are severely faded, and the grayscale value change rate of the markings is greater than 35%. The inkjet printing layer is peeling off, and the markings are fading. The inkjet printing layer is peeling off, and the markings are fading. The inkjet printing layer is peeling off, and the markings are fading. The inkjet printing layer is severely yellowed and cracked, ΔYI>5 Comparative Example 2 The inkjet printing layer is free of defects and the markings are clear. The label has slightly faded, with a grayscale value change rate of 12-15%. The inkjet printing layer showed no abnormalities. The markings have faded and the coding layer has peeled off. Slight bubbling of the inkjet printing layer The inkjet printing layer shows slight yellowing, with no cracking or peeling, and ΔYI > 5. Comparative Example 3 The inkjet printing layer is free of defects and the markings are clear. The inkjet printing layer is exposed, the markings are severely faded, and the grayscale value change rate is greater than 20%. The inkjet printing layer is peeling off, and the markings are fading. The inkjet printing layer is peeling off, and the markings are fading. Faded logo Yellowing and cracking of the inkjet printing layer; ΔYI > 5 Comparative Example 4 The inkjet printing layer is free of defects and the markings are clear. The label has slightly faded, with a grayscale value change rate >5%. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. Slight peeling of the inkjet printing layer The inkjet printing layer shows slight yellowing but no cracking; ΔYI > 5. Comparative Example 5 The inkjet printing layer is free of defects and the markings are clear. The label has slightly faded, with a grayscale value change rate >5%. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. The inkjet printing layer showed no abnormalities. Yellowing of the inkjet printing layer, ΔYI>5 The three-layer structure of this application provides a coding layer with good wear resistance, corrosion resistance, and oil resistance, which solves the problems of easy peeling, blurring, and discoloration of the markings in Comparative Example 1 (existing technology directly uses single-layer coding).

[0048] The polyurethane acrylate containing isocyanate in Example 2 is replaced by the polyurethane acrylate described above as a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for inkjet printing on tubes based on multilayer UV-curable ink, characterized in that: Includes the following steps: A UV base coat, a UV white ink marking layer, and a UV protective layer are sequentially sprayed onto the outer surface of the tubing. These layers are then stacked to form the tubing coding layer. Both the UV base coat and the UV protective layer are transparent adhesive layers. The UV primer forming the UV base coat is mainly composed of isocyanate-containing polyurethane acrylate resin; the UV white ink marking ink forming the UV white ink marking layer is mainly composed of epoxy acrylate resin; and the UV protective adhesive forming the UV protective layer is mainly composed of amino-terminated fluorinated prepolymer modified acrylate resin.

2. The tube marking method based on multilayer UV-curable ink according to claim 1, characterized in that: The UV primer comprises the following components in parts by weight: 100 parts of isocyanate-containing polyurethane acrylate, 5-7 parts of trimethylolpropane triacrylate, 10-12 parts of dipentaerythritol hexaacrylate, 3-5 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-2 parts of isocyanate end-capping agent, 2-3 parts of organosilicon coupling agent KH-550, 0.5-1 part of leveling agent, and 0.3-0.5 parts of fumed silica.

3. The tube marking method based on multilayer UV-curable ink according to claim 1, characterized in that: The UV white ink marking ink comprises the following components in parts by weight: 55 parts epoxy acrylate resin, 10-15 parts 1,6-hexanediol diacrylate, 8-12 parts neopentyl glycol polymethyl ethylene oxide diacrylate, 20-25 parts titanium dioxide, 2-4 parts photoinitiator TPO, 2-3 parts ethyl aminopropionate, 1-2 parts dispersant BYK-110, and 0.3-0.5 parts defoamer BYK-088.

4. The tube marking method based on multilayer UV-curable ink according to claim 1, characterized in that: The UV protective adhesive comprises the following components in parts by weight: 60 parts of amino-terminated fluorinated prepolymer modified acrylate resin, 5-8 parts of polymethyl methacrylate, 2-3 parts of 3-aminopropyltriethoxysilane, 8-12 parts of pentaerythritol tetraacrylate, 2-4 parts of photoinitiator BAPO, 1-2 parts of nano silica, and 0.5-1 part of UV absorber UV-531.

5. The tube marking method based on multilayer UV-curable ink according to claim 2, characterized in that: The leveling agent is BYK-333.

6. The tube marking method based on multilayer UV-curable ink according to claim 2, characterized in that: The isocyanate capping agent is methyl ethyl ketone oxime.

7. The tube marking method based on multilayer UV-curable ink according to claim 1, characterized in that: The specific steps include the following: S1. Use a glue sprayer to evenly spray UV primer onto the outer surface of the glue tube, controlling the wet film thickness to 8-12μm; after spraying, place the glue tube into a heating chamber to heat the primer layer to 130-135℃ and hold for 20-30 minutes; then place the glue tube under a UV curing device for UV irradiation, with a UV wavelength of 365nm and a light intensity of 100mW / cm². 2 The light exposure time is 3-5 seconds, forming a transparent base layer; S2. Use a small character inkjet printer to precisely spray UV white ink onto the base layer to form a label layer with a preset pattern or text. After spraying, immediately send the tube into a UV curing device for UV irradiation. The UV wavelength is 365nm and the irradiation intensity is 120mW / cm². 2 The light exposure time is 4-6 seconds, forming a UV white ink marking layer; S3. Use a spray gun to evenly spray UV protective adhesive onto the UV white ink marking layer, and control the wet film thickness to 10-15μm. After the coating is completed, the tube is sent into a UV curing device for full UV irradiation. The UV wavelength is 365nm, the light intensity is 150mW / cm², and the irradiation time is 8-12s. This allows the UV base coat, UV white ink marking layer, and UV protective layer to be fully cured and cross-linked to form an integrated structure, ultimately forming the tube coding layer.

8. The tube marking method based on multilayer UV-curable ink according to claim 2, characterized in that: The preparation method of the UV primer includes the following steps: Isocyanate-containing polyurethane acrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate are sequentially added to a stirred tank and mixed under a nitrogen protective atmosphere, with the mixing temperature controlled at 40-50℃; 2-hydroxy-2-methyl-1-phenyl-1-propanone is added to the stirred tank, and stirring continues for 15-20 minutes, maintaining the temperature at 40-50℃; the temperature inside the stirred tank is lowered to 25-30℃, and isocyanate end-capping agent butanone oxime and organosilicon coupling agent KH-550 are added sequentially, and stirred until homogeneous; finally, leveling agent BYK-333 and fumed silica are added, and the mixture is dispersed at high speed. After dispersion, the mixture is filtered through a 200-300 mesh filter to remove impurities and undispersed particles, yielding the UV primer.

9. The tube marking method based on multilayer UV-curable ink according to claim 3, characterized in that: The preparation method of the UV white ink marking ink includes the following steps: epoxy acrylate resin, 1,6-hexanediol diacrylate, and neopentyl glycol polymethyl ethylene oxide diacrylate are added to a dispersion tank and stirred until uniformly mixed. The mixing temperature is controlled at 30-40℃ to obtain a resin mixture. Dispersant BYK-110 is added to the resin mixture and stirred for 5-10 minutes. Titanium dioxide is gradually added while stirring. After the titanium dioxide is added, it is dispersed at high speed, and the dispersion temperature is controlled at 35-45℃. The dispersed mixture is sent to a sand mill for grinding. The ground mixture is returned to the dispersion tank, and photoinitiator TPO, ethyl aminopropionate, and defoamer BYK-088 are added. The mixture is stirred and mixed. After stirring, it is filtered through a 300-400 mesh filter to obtain the UV white ink marking ink.

10. The tube marking method based on multilayer UV-curable ink according to claim 4, characterized in that: The preparation method of the UV protective adhesive includes the following steps: amino-terminated fluorinated prepolymer modified acrylate resin, polymethyl methacrylate, and pentaerythritol tetraacrylate are added to a stirred tank and stirred and mixed at a temperature of 30-40℃; after uniform mixing, 3-aminopropyltriethoxysilane is added to the stirred tank, the temperature is maintained at 30-40℃, and stirring is continued until uniform. Then, photoinitiator BAPO and UV absorber UV-531 are added, and the mixture is stirred for 10-15 minutes before adding nano-silica and dispersing at high speed; the dispersed mixture is filtered through a 200-300 mesh filter to remove impurities and agglomerated nanoparticles, thus obtaining the UV protective adhesive.

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