Ink-jet printing ink composition, ink-jet printing ink and ink-jet direct plate-making material

Abstract

The application provides an ink-jet printing ink composition, an ink-jet printing ink and an ink-jet direct plate-making material. The ink-jet printing ink composition comprises: 10-60 parts by weight of a UV curable prepolymer, 1-10 parts by weight of a photoinitiator and 30-80 parts by weight of an active diluent monomer. The UV curable prepolymer comprises an organosilicon modified epoxy acrylate prepolymer, so as to improve the water resistance and the adhesive force of the plate material formed by using the ink composition, and further enhancing the printing durability.

Description

Inkjet printing ink composition, inkjet printing ink and inkjet direct platemaking plate

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311439770.1, filed on October 31, 2024, entitled “Inkjet printing ink composition, inkjet printing ink and inkjet direct platemaking plate,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of inkjet printing technology, and in particular to an inkjet printing ink composition, inkjet printing ink, and an inkjet direct-to-plate plate. Background Art

[0004] As an additive manufacturing printing process, inkjet printing offers advantages such as energy conservation, environmental protection, and data variability. UV inkjet printing is VOC-free, allows for rapid material shaping, and enables three-dimensional printing and platemaking through layer-by-layer printing, thus offering significant advantages in gravure platemaking. Most UV inkjet inks on the market utilize free radical photocuring systems, which offer fast curing speeds and inexpensive raw materials. However, free radical photocuring suffers from severe oxygen inhibition, which can lead to poor surface curing. The free radical photocuring process also causes volume shrinkage, which can affect the product's adhesion properties.

[0005] A Chinese patent application, publication number CN103991270A, provides a reusable gravure roller and printing method based on inkjet printing. The entire surface of the gravure roller is provided with a number of cells of equal depth and evenly arranged. Using inkjet printing technology, oil-repellent ink droplets are sprayed into the cells in the non-image area to produce a printing plate. After printing, the ink droplets in the cells are cleaned and the plate can be remade. The gravure roller obtained by this method can be reused, but the production process of the gravure roller is the same as that of existing gravure rollers, requiring copper plating, electroengraving, and chrome plating, resulting in high production costs and complex processes. Furthermore, the platemaking inks used are hot-melt and conventional UV-curable inks, which have poor wear resistance and low printability.

[0006] Summary of the Invention

[0007] The present application provides an inkjet printing ink composition, an inkjet printing ink, and an inkjet direct-to-plate plate material, so as to improve the water resistance and adhesion of the plate material and thus enhance the run time.

[0008] The first aspect of the present application provides an inkjet printing ink composition, which includes: 10-60 parts by weight of a UV prepolymer, 1-10 parts by weight of a photoinitiator, and 30-80 parts by weight of a reactive diluent monomer, wherein the UV prepolymer includes a silicone-modified epoxy acrylate prepolymer.

[0009] In any embodiment of the first aspect of the present application, the organosilicon-modified epoxy acrylate prepolymer has a structure shown in Formula I,

[0010] wherein m is any integer from 1 to 50, each R1 is independently any one of a C1-C50 alkylene group, a C2-C50 alkenylene group, and a C6-C30 arylene group; preferably, each R1 is independently any one of a C1-C20 alkylene group, a C2-C20 alkenylene group, and a C6-C20 arylene group; preferably, each R1 is independently any one of a C1-C8 alkylene group, a C2-C6 alkenylene group, and a phenyl group; R2 is any one of a hydroxyl group, a C1-C10 alkoxy group, and a phenoxy group; preferably, R2 is any one of a hydroxyl group, a C1-C3 alkoxy group, and a phenoxy group; preferably, R2 is a hydroxyl group, a methoxy group, or a phenoxy group.

[0011] In any embodiment of the first aspect of the present application, the number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 20,000-80,000; preferably, the number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 30,000-60,000.

[0012] In any embodiment of the first aspect of the present application, the UV prepolymer further includes one or more of polyurethane acrylate prepolymer, polyester acrylate prepolymer, acrylate prepolymer, and silicone oligomer, and preferably the mass content of silicone-modified epoxy acrylate prepolymer in the UV prepolymer is greater than 50%.

[0013] In any embodiment of the first aspect of the present application, the photoinitiator includes a free radical photoinitiator and a cationic photoinitiator; the molar ratio of the free radical photoinitiator to the cationic photoinitiator is (4-8):1.

[0014] In any embodiment of the first aspect of the present application, the free radical photoinitiator is selected from one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-isopropylthioxanthone, benzophenone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, and α-hydroxyisopropylbenzophenone; and / or the cationic photoinitiator is selected from one or more of diphenyl hexafluoroarsenic acid iodonium salt, benzanilide salt, and benzoylphenothiazine salt.

[0015] In any embodiment of the first aspect of the present application, the active diluent monomer includes an acrylate monomer containing a vinyl ether at the end, and preferably the active diluent monomer is selected from one or more of vinyl ether-tetramethylene acrylate, vinyl ether-1,6-hexanediol diacrylate, vinyl ether diethylene glycol diacrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-dipropylene glycol diacrylate, and vinyl ether-pentaerythritol triacrylate.

[0016] In any embodiment of the first aspect of the present application, the inkjet printing ink composition further comprises 0.01-5 parts by weight of an auxiliary agent, wherein the auxiliary agent comprises fluorine-modified polysilane, and preferably the fluorine-modified polysiloxane comprises polytrifluoropropylmethylsiloxane or organic fluorine polydimethylsiloxane.

[0017] The second aspect of the present application provides an inkjet printing ink, which is formed by mixing the inkjet printing ink composition provided by any embodiment of the first aspect. Preferably, the rotational viscosity of the inkjet printing ink at 25°C is 3mPa·s-30mPa·s.

[0018] The third aspect of the present application provides an inkjet direct platemaking plate, which is prepared by an inkjet direct platemaking process. The ink used in the inkjet direct platemaking process is the inkjet printing ink provided by any embodiment of the above-mentioned second aspect. Preferably, the surface energy of the inkjet direct platemaking plate is 32mN / m-36mN / m; preferably, the cell depth of the inkjet direct platemaking plate is 10μm-100μm, and further preferably 30μm-60μm.

[0019] In any embodiment of the third aspect of the present application, the inkjet direct platemaking process includes using an inkjet printer to print ink layer by layer onto a roller plate base or a flat plate base, and then photocuring to form a gravure cell structure to obtain a plate material. Preferably, the photocuring molding uses a UV-LED light source, further preferably the wavelength of the UV-LED light source is between 365nm and 410nm, and more preferably the light intensity of the UV-LED light source is greater than 6W / cm 2 .

[0020] The organosilicon-modified epoxy acrylate prepolymer in the inkjet printing ink composition of the present application can participate in free radical photocuring reaction and cationic photocuring reaction at the same time, can effectively reduce oxygen inhibition, achieve high curing speed and high crosslinking density, and excellent water resistance. Moreover, the organosilicon-modified epoxy acrylate prepolymer can significantly reduce the brittleness of epoxy resin, increase toughness and elasticity of chain segments, improve adhesion, so that the ink formed by the composition of the present application can realize multi-layer superposition printing on a roller or flat plate substrate, alleviate the brittle cracking and shedding of the ink layer, and the printing resistance is extremely high, and even the printing resistance of the plate formed by some embodiments can reach 50,000 prints. In addition, since cationic oxidation sensitization can only be triggered when the energy is very high, the ink formed by the ink composition of the present application has high system storage stability under normal conditions and is not prone to conjunctival curing. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are further described in detail with reference to the following examples. The detailed description of the following examples is used to illustrate the principles of the present invention, but is not intended to limit the scope of the present invention, that is, the present invention is not limited to the described examples.

[0022] As analyzed in the background technology of this application, the inkjet direct platemaking plate in the prior art has insufficient press life. In order to solve this problem, this application provides an inkjet printing ink composition, inkjet printing ink and inkjet direct platemaking plate.

[0023] In a first embodiment of the present application, an inkjet printing ink composition is provided, which includes: 10-60 parts by weight of a UV prepolymer, 1-10 parts by weight of a photoinitiator, and 30-80 parts by weight of a reactive diluent monomer, wherein the UV prepolymer includes a silicone-modified epoxy acrylate prepolymer.

[0024] The organosilicon-modified epoxy acrylate prepolymer in the inkjet printing ink composition of the present application can participate in free radical photocuring reaction and cationic photocuring reaction at the same time, can effectively reduce oxygen inhibition, achieve high curing speed and high crosslinking density, and excellent water resistance. Moreover, the organosilicon-modified epoxy acrylate prepolymer can significantly reduce the brittleness of epoxy resin, increase toughness and elasticity of chain segments, improve adhesion, so that the ink formed by the composition of the present application can realize multi-layer superposition printing on a roller or flat plate substrate, alleviate the brittle cracking and shedding of the ink layer, and the printing resistance is extremely high, and even the printing resistance of the plate formed by some embodiments can reach 50,000 prints. In addition, since cationic oxidation sensitization can only be triggered when the energy is very high, the ink formed by the ink composition of the present application has high system storage stability under normal conditions and is not prone to conjunctival curing.

[0025] The organosilicon-modified epoxy acrylate prepolymer used in the present application can be prepared by a known preparation method or a commercial organosilicon-modified epoxy acrylate prepolymer.

[0026] In some embodiments, the inkjet printing ink composition includes: 30-50 parts by weight of a UV prepolymer, 6-10 parts by weight of a photoinitiator, and 35-65 parts by weight of a reactive diluent monomer.

[0027] In some embodiments of the present application, the organosilicon-modified epoxy acrylate prepolymer has a structure shown in Formula I,

[0028] wherein m is any integer from 1 to 50, each R1 is independently any one of a C1-C50 alkylene group, a C2-C50 alkenylene group, and a C6-C30 arylene group; preferably, each R1 is independently any one of a C1-C20 alkylene group, a C2-C20 alkenylene group, and a C6-C20 arylene group; preferably, each R1 is independently any one of a C1-C8 alkylene group, a C2-C6 alkenylene group, and a phenyl group; R2 is any one of a hydroxyl group, an alkoxy group, and a phenoxy group; preferably, R2 is any one of a hydroxyl group, a C1-C3 alkoxy group, and a phenoxy group; preferably, R2 is a hydroxyl group, a methoxy group, or a phenoxy group.

[0029] The silicone-modified epoxy acrylate prepolymer grafts silicone groups between the two epoxy acrylate groups, enhancing the elasticity of the prepolymer chain segments and significantly improving the prepolymer's flexibility, water resistance, and heat resistance. Furthermore, the hydroxyl, methoxy, and phenoxy groups in the silicone groups exhibit excellent adhesion to metals, thus enhancing the ink's adhesion to the substrate using R2. Furthermore, a 1:1 molar ratio of epoxy to acrylate groups significantly reduces the curing shrinkage of the acrylate, improving adhesion.

[0030] In addition, when R1 is selected from C1-C50 alkylene or C2-C50 alkenylene, the alicyclic epoxy group has no benzene ring and will not photolyze to produce quinone intermediates like bisphenol A epoxy, causing yellowing of the system and brittleness of the ink layer.

[0031] In some embodiments, m in the above formula I may preferably be 1-30, 1-20, 1-15, etc., for example, it may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 20, 25, 30, 35, 40, 45 or 50.

[0032] In some embodiments, R1 is independently methylene, ethylene, propylene, vinylidene, propenylene, or phenyl, preferably R1 is independently methylene, ethylene, vinylidene, or phenyl, and more preferably R1 is independently methylene, ethylene, or vinylidene.

[0033] In some embodiments, the number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 20,000-80,000; preferably, the number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 30,000-60,000. This number average molecular weight range results in a viscosity of the resulting ink of less than 30 mPa·s. Furthermore, if the prepolymer molecular weight is too low, the number of active groups is too small, which affects the performance of the prepolymer. If the prepolymer molecular weight is too high, the viscosity is too high, and the amount of prepolymer added to the ink to meet good printing requirements is very small, resulting in a lack of significant performance effect of the prepolymer. Furthermore, if the molecular weight of the prepolymer is too high, the chain segments are too long, the cross-linking rate is reduced, and the improvement in the ink's water resistance is insufficient.

[0034] In some embodiments, the UV prepolymer further comprises one or more of a polyurethane acrylate prepolymer, a polyester acrylate prepolymer, an acrylate prepolymer, or a silicone oligomer. Preferably, the weight content of the silicone-modified epoxy acrylate prepolymer in the UV prepolymer is greater than 50%. A content greater than 50% can more effectively reduce oxygen inhibition and volume shrinkage, significantly improving the system's flexibility and water resistance, and further enhancing print run. The combination of silicone-modified epoxy acrylate prepolymers with conventional UV prepolymers can significantly reduce product costs.

[0035] Those skilled in the art can adjust the polymerization rate of the prepolymer and the mechanical properties of the resulting cured product by adjusting the composition of the photoinitiator. In some embodiments, the photoinitiator includes a free radical photoinitiator and a cationic photoinitiator; the molar ratio of the free radical photoinitiator to the cationic photoinitiator is (4-8):1. The free radical photoinitiator is used to initiate the free radical photocuring reaction, and the higher the proportion of the free radical photoinitiator, the greater the photocuring speed and crosslinking density, and the better the water resistance of the resulting plate. When the molar ratio of the free radical photoinitiator to the cationic photoinitiator is (4-8):1, the sensitization efficiency of the cationic photoinitiator is also high, which can greatly improve the volume shrinkage defect caused by free radical photocuring, better improve the toughness and adhesion of the resulting plate, and further enhance the run time.

[0036] The free radical photoinitiator and cationic photoinitiator used in the present application are selected from the corresponding initiator types commonly used in the prior art. In some embodiments, the free radical photoinitiator includes but is not limited to one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-isopropylthioxanthone, benzophenone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, and α-hydroxyisopropylbenzophenone.

[0037] In some embodiments, the cationic photoinitiator includes, but is not limited to, one or more of diphenyl iodonium hexafluoroarsenate salts, benzanilide salts, and benzoylphenothiazine salts.

[0038] The free radical initiator in the above-mentioned inkjet printing ink composition can absorb energy with a wavelength of 365nm-405nm. The generated free radicals can be oxidized and sensitized by the cationic photoinitiator, initiating cationic polymerization, so that the initiation wavelength of the cationic photoinitiator transitions from 250-300nm to 365-405nm, realizing UV-LED cationic light curing and avoiding the high energy consumption and ozone pollution of mercury lamps.

[0039] In addition, experiments have found that cationic initiators such as diphenyl iodonium hexafluoroarsenate, benzanilide, and benzoylphenothiazine can be easily sensitized, with an initiation wavelength of 365-405 nm and high initiation efficiency.

[0040] The reactive diluent monomer can be selected from conventional photoinitiated reactive diluent monomers. In some embodiments, the reactive diluent monomer comprises an acrylate monomer containing a terminal vinyl ether. Vinyl ether-modified acrylate reactive diluent monomers have higher reactivity, significantly increasing the reaction rate. Furthermore, vinyl ether-modified acrylates significantly increase the compatibility and solubility of the prepolymer and cationic initiator, resulting in improved storage stability of the system.

[0041] In some embodiments, the reactive diluent monomer includes but is not limited to one or more of vinyl ether-tetramethylene glycol acrylate, vinyl ether-1,6-hexanediol diacrylate, vinyl ether-diethylene glycol diacrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-dipropylene glycol diacrylate, and vinyl ether-pentaerythritol triacrylate.

[0042] In some embodiments, the inkjet printing ink composition further includes 0.01-5 parts by weight of an auxiliary agent, wherein the auxiliary agent includes a fluorine-modified polysilane. Due to the improved hydrophobicity of the fluorine-modified polysilane, the ink formed by the ink composition containing the fluorine-modified polysilane has a lower surface energy and better wear resistance after curing. In some embodiments, the fluorine-modified polysilane includes but is not limited to polytrifluoropropylmethylsiloxane and organofluorine polydimethylsiloxane.

[0043] In the second embodiment of the present application, an inkjet printing ink is provided. The inkjet printing ink is mixed with any one of the inkjet printing ink compositions of the first embodiment described above. Preferably, the rotational viscosity of the inkjet printing ink at 25° C. is 3 mPa·s-30 mPa·s.

[0044] The organosilicon-modified epoxy acrylate prepolymer in the inkjet printing ink of the present application can participate in free radical photocuring reaction and cationic photocuring reaction at the same time, which can effectively reduce oxygen inhibition, achieve high curing speed and high crosslinking density, and excellent water resistance. In addition, the organosilicon-modified epoxy acrylate prepolymer can significantly reduce the brittleness of epoxy resin, increase toughness and elasticity of chain segments, improve adhesion, so that the ink can be printed in multiple layers on a roller or flat plate substrate, alleviate the brittle cracking and shedding of the ink layer, and have extremely high printability. Even the printability of the plate formed by some embodiments can reach 50,000 prints. In addition, since cationic oxidation sensitization can only be triggered when the energy is very high, the ink of the present application has high system storage stability under normal conditions and is not prone to conjunctival curing.

[0045] The third embodiment of the present application provides an inkjet direct platemaking plate, which is prepared by an inkjet direct platemaking process. The ink used in the inkjet direct platemaking process is the inkjet printing ink provided in the second embodiment. The surface energy of the inkjet direct platemaking plate is preferably 32mN / m-36mN / m.

[0046] The plate material of the present application has excellent water resistance and extremely high press life. In some embodiments, the press life of the plate material can even reach 50,000 prints. Using the above-mentioned ink, an unlimited number of overlapping prints can be performed, so the cell depth of the inkjet direct plate material can be adjusted at will. The cell depth of different areas can also be controlled and adjusted. Plates with different cell depths can be used for different printing patterns and color requirements. The cell depth of the inkjet direct plate material is controllable between 10μm and 100μm. In some embodiments, the cell depth of the inkjet direct plate material is 30μm to 60μm, and the printing effect is good.

[0047] In some embodiments, the above-mentioned inkjet direct platemaking process includes using an inkjet printer to print ink layer by layer onto a roller plate base or a flat plate base, and then photocuring to form a gravure cell structure to obtain a plate material. Preferably, the photocuring is performed using a UV-LED light source, and further preferably, the wavelength of the UV-LED light source is between 365nm and 410nm. In some embodiments, the wavelength of the UV-LED light source is selected from one or more of 365nm, 375nm, 385nm, 395nm, and 405nm. More preferably, the light intensity of the UV-LED light source is greater than 6W / cm 2 .

[0048] The above-mentioned inkjet printer can be purchased commercially, and the print head is a print head suitable for a UV system, preferably but not limited to Ricoh, Komei, Kyocera, Starlight, Epson, Xaar, Fuji, Samba, Toshiba, Samsung, and Panasonic print heads.

[0049] The following examples and comparative examples will further illustrate the beneficial effects of the present application, but the scope of the present invention is not limited to these examples.

[0050] Compound Description:

[0051] The sources of the above-mentioned silicone-modified epoxy acrylate prepolymers are as follows:

[0052] Silicone-modified epoxy acrylate prepolymers A1-A5 were all from Boxing, Guangdong.

[0053] Example 1

[0054] 4 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1 wt% of 2-isopropylthioxanthone, and 1 wt% of benzoylphenothiazine salt, accounting for the total ink volume, are added to a mixture of 40 wt% of vinyl ether-tetrahydrofuran acrylate and 23 wt% of vinyl ether-dipropylene glycol diacrylate and stirred until completely dissolved. 30 wt% of organosilicon-modified epoxy acrylate prepolymer A1 (molecular weight 35,000) and 1 wt% of organofluorinated polydimethylsiloxane (purchased from Efcona) are then added thereto and stirred and dispersed evenly to obtain a photocurable inkjet ink B1.

[0055] On a clean metal roller, use a Ricoh G5 printhead to print the light-curable inkjet ink B1 layer by layer onto the roller. Print 4 layers at a light intensity of 8W / cm 2 , a UV-LED light source with a wavelength of 395nm is used for photocuring to construct the gravure cell structure, and a roller C1 suitable for gravure printing is obtained.

[0056] Example 2

[0057] 5.5 wt% of α-hydroxyisopropyl benzophenone and 1 wt% of diphenyl iodonium hexafluoroarsenate, accounting for the total amount of the ink, are added to 48 wt% of vinyl ether-diethylene glycol diacrylate and stirred until completely dissolved. Then, 25 wt% of silicone-modified epoxy acrylate prepolymer A1 (molecular weight 35,000) and 20% of polyurethane acrylate (molecular weight 50,000, purchased from Double Bond Chemical) and 0.5 wt% of organofluorinated polydimethylsiloxane (purchased from Efcona) are added and stirred and dispersed evenly to obtain a photocurable inkjet ink B2.

[0058] On a clean metal roller, use a Ricoh G5 nozzle to print the light-curable inkjet ink B2 layer by layer onto the roller. Print 4 layers with a light intensity of 8W / cm 2 , a UV-LED light source with a wavelength of 365nm is used for photocuring to construct the gravure cell structure, and a roller C2 suitable for gravure printing is obtained.

[0059] Example 3

[0060] 5wt% (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 3wt% benzophenone and 2wt% benzanilide salt, accounting for the total amount of ink, are added to 47wt% vinyl ether-diethylene glycol diacrylate and stirred until completely dissolved. Then, 40wt% of silicone-modified epoxy acrylate prepolymer A2 (molecular weight 60,000) and 3wt% polytrifluoropropyl methylsiloxane (purchased from Hubei Fangde New Materials Co., Ltd.) are added thereto and stirred and dispersed evenly to obtain photocurable inkjet ink B3.

[0061] On a clean metal roller, use a Ricoh G5 nozzle to print the light-curable inkjet ink B2 layer by layer onto the roller. Print 4 layers with a light intensity of 12W / cm 2 , a UV-LED light source with a wavelength of 385nm is used for photocuring to construct the mesh structure of the gravure, and a roller C3 suitable for gravure printing is obtained.

[0062] Example 4

[0063] 5.5 wt% of 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone and 1 wt% of diphenyl iodonium hexafluoroarsenate, accounting for the total ink volume, were added to 42 wt% of vinyl ether-2-phenoxyethyl acrylate and stirred until completely dissolved. 50 wt% of silicone-modified epoxy acrylate prepolymer A3 (molecular weight 50,000) and 1.5 wt% of polytrifluoropropylmethylsiloxane (purchased from Hubei Fangde New Materials Co., Ltd.) were added thereto and stirred and dispersed evenly to obtain a photocurable inkjet ink B4.

[0064] On a clean metal roller, use a Ricoh Komei 1024i printhead to print the light-curable inkjet ink B4 onto the roller layer by layer. Print 4 layers at a light intensity of 15W / cm 2 , a mixed UV-LED light source with a wavelength of 365nm and 405nm in a ratio of 1:5 is used for photocuring to construct the gravure cell structure, and a roller C4 suitable for gravure printing is obtained.

[0065] Example 5

[0066] 4 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1 wt% of 2-isopropylthioxanthone, and 1 wt% of benzoylphenothiazine salt, which account for 4 wt% of the total ink, are added to 35 wt% of vinyl ether-1,6-hexanediol diacrylate and stirred until completely dissolved. Then, 35 wt% of silicone-modified epoxy acrylate prepolymer A3 (molecular weight 50,000) and 22% of polyester acrylate (molecular weight 50,000, purchased from Double Bond Chemical) and 2 wt% of organic fluorine polydimethylsiloxane (purchased from Efcona) are added thereto and stirred and dispersed evenly to obtain a photocurable inkjet ink B5.

[0067] On a clean metal roller, use an Epson 3200 nozzle to print the light-curable inkjet ink B5 layer by layer onto the roller. Print 8 layers at a light intensity of 10W / cm 2 , UV-LED light source with a wavelength of 395nm is used for photocuring to construct the gravure cell structure, and a roller C5 suitable for gravure printing is obtained.

[0068] Example 6

[0069] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the content of organosilicon-modified epoxy acrylate prepolymer A1 (molecular weight 35,000) was 10%, to obtain light-curable ink B6.

[0070] The resulting roller C6 is suitable for gravure printing.

[0071] Example 7

[0072] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the organosilicon-modified epoxy acrylate prepolymer was A4 (molecular weight 20,000), to obtain light-curable ink B7.

[0073] The resulting roller C7 is suitable for gravure printing.

[0074] Example 8

[0075] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the organosilicon-modified epoxy acrylate prepolymer was A5 (molecular weight 80,000), and a light-curing ink B8 was obtained.

[0076] The resulting roller C8 is suitable for gravure printing.

[0077] Example 9

[0078] Ink was prepared and plate printing was performed according to the method of Example 1, except that the prepolymer was 50% silicone-modified epoxy acrylate prepolymer A1 (molecular weight 35,000) and 50% polyurethane acrylate (purchased from Double Bond Chemical) to obtain photocurable ink B9.

[0079] The resulting roller C9 is suitable for gravure printing.

[0080] Example 10

[0081] Ink was prepared and plate printing was performed according to the method of Example 1, except that the prepolymer was 30% of silicone-modified epoxy acrylate prepolymer A1 (molecular weight 35,000) and 70% of polyurethane acrylate (purchased from Double Bond Chemical), to obtain light-curable ink B10.

[0082] The resulting roller C10 is suitable for gravure printing.

[0083] Example 11

[0084] Ink was prepared and plate printing was performed according to the method of Example 1, except that the total content of the photoinitiator was 1%, including 0.6 wt % of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 0.2 wt % of 2-isopropylthioxanthone, and 0.2 wt % of benzoylphenothiazine salt to obtain photocurable ink B11.

[0085] The resulting roller C11 is suitable for gravure printing.

[0086] Example 12

[0087] Ink was prepared and platemaking printing was performed according to the method of Example 1, except that the ratio of the free radical photoinitiator to the cationic photoinitiator in the photoinitiator was 8:1, including 4.26 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1.07 wt% of 2-isopropylthioxanthone, and 0.67 wt% of benzoylphenothiazine salt, to obtain light-curable ink B12.

[0088] The resulting roller C12 is suitable for gravure printing.

[0089] Example 13

[0090] Ink was prepared and platemaking printing was performed according to the method of Example 1, except that the ratio of the free radical photoinitiator to the cationic photoinitiator in the photoinitiator was 3:1, including 3.6 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 0.9 wt% of 2-isopropylthioxanthone, and 1.5 wt% of benzoylphenothiazine salt, to obtain light-curable ink B13.

[0091] The resulting roller C13 is suitable for gravure printing.

[0092] Example 14

[0093] Ink was prepared and plate printing was performed according to the method of Example 1, except that the ratio of the free radical photoinitiator to the cationic photoinitiator in the photoinitiator was 9:1, including 4.32 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1.08 wt% of 2-isopropylthioxanthone, and 0.6 wt% of benzoylphenothiazine salt, to obtain light-curable ink B14.

[0094] The resulting roller C14 is suitable for gravure printing.

[0095] Example 15

[0096] Ink was prepared and plate printing was performed according to the method of Example 1, except that the active diluent was a mixture of 15 wt % vinyl ether-tetramethylene acrylate and 15 wt % vinyl ether-dipropylene glycol diacrylate to obtain light-curable ink B15.

[0097] The resulting roller C15 is suitable for gravure printing.

[0098] Example 16

[0099] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the content of organic fluorinated polydimethylsiloxane (purchased from Efcona) was 5%, to obtain light-curable ink B16.

[0100] The resulting roller C16 is suitable for gravure printing.

[0101] Example 17

[0102] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the cationic initiator was triarylsulfonium hexafluorophosphate salt, to obtain a photocurable inkjet ink B17.

[0103] The resulting roller C17 is suitable for gravure printing.

[0104] Example 18

[0105] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the reactive diluents were 40 wt % of tetramethylene acrylate and 23 wt % of dipropylene glycol diacrylate, to obtain a photocurable inkjet ink B18.

[0106] The resulting roller C18 is suitable for gravure printing.

[0107] Example 19

[0108] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the auxiliary agent was polyether silane (purchased from Changhui Chemical), to obtain light-curable inkjet ink B19.

[0109] The resulting roller C19 is suitable for gravure printing.

[0110] Comparative Example 1

[0111] Ink was prepared and plate-making printing was performed according to the method of Example 1, except that the prepolymer was polyurethane acrylate (molecular weight 35,000, purchased from Double Bond Chemical), to obtain light-curable inkjet ink B20.

[0112] The resulting roller C20 is suitable for gravure printing.

[0113] Comparative Example 2

[0114] 4 wt% of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1 wt% of 2-isopropylthioxanthone, and 1 wt% of triaryl sulfonium hexafluorophosphate, accounting for the total ink volume, are added to a mixture of 40 wt% of tetrahydrofuran acrylate and 23 wt% of dipropylene glycol diacrylate and stirred until completely dissolved. Then, 30 wt% of polyurethane acrylate (molecular weight 35,000, purchased from Double Bond Chemical) and 1 wt% of polyether silane (purchased from Changhui Chemical) are added thereto and stirred and dispersed evenly to obtain the photocurable inkjet ink B21.

[0115] On a clean metal roller, use a Ricoh G5 printhead to print the light-curable inkjet ink B1 layer by layer onto the roller. Print 4 layers at a light intensity of 8W / cm 2 , a UV-LED light source with a wavelength of 395nm is used for photocuring to construct the gravure cell structure, and a roller C21 suitable for gravure printing is obtained.

[0116] Test Case

[0117] (1) Viscosity test

[0118] Testing equipment: Rheometer (Anton Paar Shanghai Trading Co., Ltd.), model: MCR 302.

[0119] (2) Surface energy test after ink curing

[0120] Testing equipment: KRUSS portable contact angle meter, model: MSA.

[0121] (3) Stability test

[0122] Test method: After the ink has been placed stably for a period of time, test the viscosity. If the viscosity changes by less than 3% from the initial value, the stability is qualified.

[0123] (4) Cross-linking rate

[0124] Test method: Place 1g of ink on a glass slide and test the double bond and epoxy conversion rate of the ink under UV-LED light source in a Fourier transform infrared spectrometer equipped with a UV-LED light source, which is the cross-linking rate.

[0125] (5) Cell depth

[0126] Test equipment: Kosaka step tester, model: ET200A.

[0127] (6) Flexibility

[0128] Draw a 30-micron thick film of ink on the plastic film. After curing, fold the film 180 degrees in half. Observe the creases under a magnifying glass. If there is no breakage, it is qualified.

[0129] (7) Adhesion test

[0130] Test method: Adhesion is tested using the 100-grid scratching method according to GBT9286-1998 Scratch test for paint and varnish films. Grade 0 is the best adhesion and Grade 5 is the worst.

[0131] (8) Water resistance

[0132] Test method: Soak the sample in tap water at room temperature (20-35℃) for a certain period of time, then take it out of the water. If the film is intact without blistering, peeling, or whitening, and passes the adhesion test, then the water resistance is qualified.

[0133] (9) Printing durability

[0134] Testing equipment: gravure printing machine + stainless steel scraper.

[0135] The above test results are recorded in Table 1.

[0136] As can be seen from the data in Table 1, the photocurable inkjet ink of the present invention has low surface energy after curing, good storage stability, and can be stably stored for more than 15 months. The ink has a high curing crosslinking rate, good adhesion, good flexibility, good water resistance, and high print run.

[0137] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An inkjet printing ink composition, characterized in that The inkjet printing ink composition comprises: 10-60 parts by weight of UV prepolymer, 1-10 parts by weight of photoinitiator, and 30-80 parts by weight of active diluent monomer, wherein the UV prepolymer comprises silicone-modified epoxy acrylate prepolymer.

2. The inkjet printing ink composition according to claim 1, characterized in that The organosilicon-modified epoxy acrylate prepolymer has a structure shown in Formula I, wherein m is any integer of 1-50, each R1 is independently any one of C1-C50 alkylene, C2-C50 alkenylene, and C6-C30 arylene; preferably, each R1 is independently any one of C1-C20 alkylene, C2-C20 alkenylene, and C6-C20 arylene, preferably, each R1 is independently any one of C1-C8 alkylene, C2-C6 alkenylene, and phenyl; R2 is any one of hydroxyl, C1-C10 alkoxy, and phenoxy, preferably, R2 is any one of hydroxyl, C1-C3 alkoxy, and phenoxy, preferably, R2 is hydroxyl, methoxy, or phenoxy.

3. The inkjet printing ink composition according to claim 1 or 2, characterized in that: The number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 20,000-80,000; preferably, the number average molecular weight of the organosilicon-modified epoxy acrylate prepolymer is 30,000-60,000.

4. The inkjet printing ink composition according to any one of claims 1 to 3, characterized in that The UV prepolymer further comprises one or more of polyurethane acrylate prepolymer, polyester acrylate prepolymer, acrylate prepolymer and silicone oligomer. Preferably, the mass content of the silicone-modified epoxy acrylate prepolymer in the UV prepolymer is greater than 50%.

5. The inkjet printing ink composition according to any one of claims 1 to 4, characterized in that The photoinitiator includes a free radical photoinitiator and a cationic photoinitiator; the molar ratio of the free radical photoinitiator to the cationic photoinitiator is (4-8):

1.

6. The inkjet printing ink composition according to claim 5, characterized in that: The free radical photoinitiator is selected from one or more of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-isopropylthioxanthone, benzophenone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, and α-hydroxyisopropylbenzophenone; and / or the cationic photoinitiator is selected from one or more of diphenyl hexafluoroarsenate iodonium salt, benzanilide salt, and benzoylphenothiazine salt.

7. The inkjet printing ink composition according to any one of claims 1 to 6, characterized in that The active diluent monomer includes an acrylate monomer containing a vinyl ether at the end, and preferably the active diluent monomer is selected from one or more of vinyl ether-tetrahydrofuran acrylate, vinyl ether-1,6-hexanediol diacrylate, vinyl ether diethylene glycol diacrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-2-phenoxyethyl acrylate, vinyl ether-dipropylene glycol diacrylate, and vinyl ether-pentaerythritol triacrylate.

8. The inkjet printing ink composition according to any one of claims 1 to 7, characterized in that The inkjet printing ink composition further comprises 0.01-5 parts by weight of an auxiliary agent, wherein the auxiliary agent comprises fluorine-modified polysilane, and preferably the fluorine-modified polysilane comprises polytrifluoropropylmethylsiloxane and organic fluorine polydimethylsiloxane.

9. An inkjet printing ink, characterized in that: The inkjet printing ink is prepared by mixing the inkjet printing ink composition according to any one of claims 1 to 8, and preferably the rotational viscosity of the inkjet printing ink at 25° C. is 3 mPa·s-30 mPa·s.

10. An inkjet direct platemaking plate material, which is prepared by an inkjet direct platemaking process, characterized in that: The ink used in the inkjet direct platemaking process is the inkjet printing ink described in claim 9, and the surface energy of the inkjet direct platemaking plate is preferably 32mN / m-36mN / m; preferably, the cell depth of the inkjet direct platemaking plate is 10μm-100μm, and more preferably 30μm-60μm.

11. The inkjet direct platemaking plate according to claim 10, characterized in that: The inkjet direct platemaking process comprises using an inkjet printer to print the ink layer by layer onto a roller plate base or a flat plate base, and then photocuring to form a cell structure of a gravure plate to obtain a plate material. Preferably, the photocuring uses a UV-LED light source, and further preferably, the wavelength of the UV-LED light source is between 365nm and 410nm, and more preferably, the light intensity of the UV-LED light source is greater than 6W / cm 2 .

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