A uv-led-cured intaglio printing ink, its preparation method and application

Abstract

The application discloses a UV-LED curing intaglio printing ink, and raw materials for preparing the UV-LED curing intaglio printing ink include 20-40 wt% of a prepolymer, 20-60 wt% of a monomer, 2-50 wt% of a pigment, 3-8 wt% of a photoinitiator, 0.2-0.4 wt% of a photosensitizer, 0.5-6 wt% of a dispersant and 0.5-1 wt% of an antifoaming agent, the monomer containing a hydroxyl group or / and an acidic group accounts for 1-10 wt% of the total raw material mass of the ink, the photoinitiator is a cleavage type acyl phosphine oxide, and the photosensitizer is a photosensitizer with a benzalacetone free radical group. The application adopts the cleavage type acyl phosphine oxide as the photoinitiator, and simultaneously combines the photosensitizer with the benzalacetone free radical group to carry out a combination structure and function, so that the initiation efficiency of the ink is obviously improved while the ink has good viscosity and adhesion, and then the curing speed of the printing ink is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of gravure printing technology, specifically to a UV-LED cured gravure printing ink, its preparation method, and its application. Background Technology

[0002] Ink is a material widely used in printing, writing, and painting. It works by suspending pigments or dyes in a liquid medium, giving them fluidity and adhesion, thus enabling printing and painting on various surfaces. In the printing industry, there are many types of inks, mainly divided into solvent-based inks, water-based inks, and UV inks. Solvent-based inks are prone to environmental pollution and health threats due to the evaporation of organic solvents, and also pose flammability and explosiveness risks. Water-based inks suffer from slow evaporation rates and poor adhesion; moreover, current water-based ink systems often use co-solvents, resulting in the generation of organic waste gas. UV ink systems are gradually gaining widespread use due to their solvent-free nature, high production efficiency, and good resistance to abrasion and acids / alkalis after curing.

[0003] Traditional UV curing equipment primarily relies on mercury lamps for energy, but it suffers from several drawbacks, including: 1) short lifespan and high power consumption; 2) significant heat radiation during curing leading to substrate deformation; 3) mercury pollution, potentially causing heavy metal contamination; and 4) the need for preheating before operation, making it complex to use. In contrast, UV-LED curing (using LEDs to emit ultraviolet light for curing) offers advantages such as: 1) long lifespan; 2) low power consumption, no heavy metal pollution sources, and energy efficiency; 3) no preheating required, easy start-up and shutdown; and 4) a cold light source resulting in minimal substrate deformation. Based on these characteristics, UV-LED is particularly suitable for gravure plastic film printing. However, gravure printing produces thicker, more detailed, and more vibrant images, demanding not only high-quality curing equipment but also high viscosity, adhesion, and curing speed of the ink. For instance, UV-LED ink curing relies on ultraviolet light penetrating the coating to reach the ink's base, achieving ink drying and substrate adhesion. However, gravure printing involves thicker coatings, making it difficult for ultraviolet light to penetrate them. Furthermore, the pigments in UV-LED inks are mostly black or dark-colored, exhibiting strong absorption of ultraviolet light. This significantly reduces the initiation efficiency of the photoinitiator, resulting in a slower curing speed. Therefore, UV-LED inks used in gravure printing need to overcome the adverse effects of dark pigment absorption of ultraviolet light and their large thickness to improve the curing speed and meet the demands of actual production. However, how to improve the curing speed while maintaining good viscosity and adhesion remains a challenge. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that existing UV-LED inks for gravure printing are difficult to improve curing speed while maintaining good viscosity and adhesion of the ink, thereby providing a UV-LED curable gravure printing ink, its preparation method and application to solve the above problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A UV-LED curable gravure printing ink, wherein the raw materials for preparing the UV-LED curable gravure printing ink include: 20-40 wt% prepolymer, 20-60 wt% monomer, 2-50 wt% pigment, 3-8 wt% photoinitiator, 0.2-0.4 wt% photosensitizer, 0.5-6 wt% dispersant and 0.5-1 wt% defoamer, wherein the monomers containing hydroxyl and / or acidic groups account for 1-10 wt% of the total raw material mass of the ink, the photoinitiator is a pyrolytic acylphosphine oxide, and the photosensitizer is a photosensitizer with benzylidene ketone free groups.

[0007] Preferably, the raw materials for preparing the UV-LED curable gravure printing ink include: 25 wt% prepolymer, 30 wt% monomer, 35 wt% pigment, 6.2 wt% photoinitiator, 0.3 wt% photosensitizer, 3 wt% dispersant and 0.5 wt% defoamer, wherein the monomers containing hydroxyl or / and acidic groups account for 8 wt% of the total raw material mass of the ink.

[0008] Preferably, the prepolymer is at least one selected from polyurethane acrylate, polyester acrylate, and polyether acrylate;

[0009] And / or, the monomers that do not contain hydroxyl or / and acidic groups are at least one of neopentyl glycol diacrylate (NPGDA), tripropylene glycol diacrylate (TPGDA), triethylene glycol diacrylate (TEGDA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), acrylmorpholine (ACMO), ethoxylated trimethylolpropane triacrylate (TMP3EOTA), and isobornyl acrylate (IBOA).

[0010] Preferably, the mass ratio of the prepolymer to the monomer is 1.0:(0.8-3.0);

[0011] And / or, the pigment is a magnetic pigment.

[0012] Preferably, the magnetic pigment is at least one of iron, cobalt, nickel, or an alloy composed of at least two of the elements selected from iron, cobalt, and nickel, iron oxide, and rare earth elements.

[0013] Preferably, the cleavage-type acylphosphine oxide is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819), 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO), and ethyl 2,4,6-trimethylbenzoylphenylphosphine acid (TPO-L).

[0014] Preferably, the dispersant is at least one of the following: a polymer copolymer containing pigment affinity groups, a mixture of a compound containing pigment affinity groups and organosilicon, an ammonium polyacrylate, a high molecular weight block copolymer solution containing pigment affinity groups, an acrylate copolymer solution with basic pigment affinity groups, a copolymer having acidic groups, and an acrylate copolymer containing pigment affinity groups; wherein the pigment affinity groups are anchoring groups or groups capable of forming a double charge layer;

[0015] And / or, the defoamer is Tego-920.

[0016] The present invention also provides a method for preparing UV-LED curable gravure printing ink, which is used to prepare the above-mentioned UV-LED curable gravure printing ink.

[0017] Preferably, the preparation method includes: mixing the prepolymer and monomer under conditions without ultraviolet irradiation, then adding an antifoaming agent and a dispersant and mixing, then adding a photoinitiator and a photosensitizer and mixing, and finally adding pigment and mixing to obtain a dispersion. The dispersion is then ground and filtered to obtain the UV-LED curable gravure printing ink. That is, in this invention, the dispersant and other substances are first evenly dispersed before adding the pigment. If all substances are added in one step, uneven dispersion is likely to occur.

[0018] Preferably, the grinding process is carried out to a particle size of ≤5μm.

[0019] The present invention also provides the application of the UV-LED curable gravure printing ink prepared by the above-mentioned UV-LED curable gravure printing ink preparation method in gravure printing on plastic substrates.

[0020] In this invention, the monomer containing hydroxyl and / or acidic groups includes monomers containing hydroxyl groups, monomers containing acidic groups, or monomers containing both hydroxyl and acidic groups. Generally, due to their special structures, suppliers only indicate the presence of these groups, without specifying their exact structural formulas or types. For example, SR 9051NS, Sartoma.

[0021] In this invention, the photosensitizer with benzylidene ketone free groups includes: 1208, Shanghai Lianzhi.

[0022] The technical solution of this invention has the following advantages:

[0023] A UV-LED curable gravure printing ink is disclosed. The raw materials for preparing the UV-LED curable gravure printing ink include: 20-40 wt% prepolymer, 20-60 wt% monomer, 2-50 wt% pigment, 3-8 wt% photoinitiator, 0.2-0.4 wt% photosensitizer, 0.5-6 wt% dispersant, and 0.5-1 wt% defoamer. The monomers containing hydroxyl and / or acidic groups account for 1-10 wt% of the total raw material mass of the ink. The photoinitiator is a pyrolytic acylphosphine oxide, and the photosensitizer is a photosensitizer with benzylidene ketone free groups. This invention uses a pyrolytic acylphosphine oxide as the photoinitiator, combined with a photosensitizer with benzylidene ketone free groups, to achieve a combined structure and effect. This significantly improves the initiation efficiency of the ink while ensuring good viscosity and adhesion, thereby greatly increasing the curing speed of the printing ink. Detailed Implementation

[0024] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0025] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0026] The raw materials used in the following embodiments and comparative examples are:

[0027] Prepolymers (Polyester acrylate 1: PO 94F, BASF; Polyester acrylate 2: CN 2270NS, Sartoma; Polyester acrylate 3: CN 2273, Sartoma);

[0028] Monomers without hydroxyl or / and acidic groups (ethoxylated trimethylolpropane triacrylate: EM2380, Changxing Chemical; acrylmorpholine: ACMO, Jiuri Chemical; cyclotrimethylolpropane methyl acetal acrylate: EM212, Changxing Chemical; monofunctional acrylate: DM-013, Double Bond Chemistry);

[0029] Monomers containing hydroxyl and / or acidic groups (trifunctional acrylates containing acidic groups: SR 9051NS, Sartoma);

[0030] Cracked acylphosphine oxide photoinitiators (ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), IGM Corporation; bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819), IGM Corporation);

[0031] Isopropylthioxanthone photoinitiator (ITX, IGM Corporation);

[0032] Photosensitizers containing benzyl ketone free radicals (1208, Shanghai Lianzhi);

[0033] Tertiary amine photosensitizers (IGM, EDB);

[0034] Dispersant (copolymer containing acidic groups: Tech 598, Tiger Additives);

[0035] Defoamer (Tego 920; Evonik).

[0036] Example 1

[0037] This embodiment provides a UV-LED curable gravure printing ink, the composition and ratio of which are as follows: 15wt% polyester acrylate 1, 10wt% polyester acrylate 3, 19wt% trimethylolpropane triacrylate ethoxylate, 18wt% N-acryloylmorpholine, 2wt% trifunctional acrylate containing acidic groups, 22wt% ferrite, 4wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 4wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.2wt% photosensitizer, 5.3wt% copolymer containing acidic groups, and 0.5wt% defoamer.

[0038] The aforementioned UV-LED curable gravure printing ink is prepared using the following process steps:

[0039] Under natural light conditions, the monomers are mixed and stirred until a clear, transparent liquid is obtained. The prepolymer is slowly added and stirred for 20 minutes until homogeneous. The dispersant and defoamer are added to the liquid and stirred for 20 minutes until homogeneous. The photoinitiator and photosensitizer are added to the liquid and stirred for 30 minutes until homogeneous. The ferrite magnetic pigment is added to the liquid and stirred for 50 minutes until homogeneous. The mixture is then ground twice to form beads with a particle size of 0.8-1.0 mm. After grinding, the mixture is filtered through a 4 μm pore size filter to obtain the final product.

[0040] Example 2

[0041] This embodiment provides a UV-LED curable gravure printing ink, the composition and ratio of which are: 15wt% polyester acrylate 2, 15wt% polyester acrylate 3, 8.5wt% cyclotrimethylolpropane methyl acetal acrylate, 8wt% monofunctional acrylate, 8wt% trifunctional acrylate containing acidic groups, 36wt% ferrite, 3wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 3wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.2wt% photosensitizer, 2.8wt% copolymer containing acidic groups, and 0.5wt% defoamer.

[0042] The aforementioned UV-LED curable gravure printing ink is prepared using the following process steps:

[0043] Under natural light conditions, the monomers are mixed and stirred until a clear, transparent liquid is obtained. The prepolymer is slowly added and stirred for 20 minutes until homogeneous. The dispersant and defoamer are added to the liquid and stirred for 20 minutes until homogeneous. The photoinitiator and photosensitizer are added to the liquid and stirred for 30 minutes until homogeneous. The ferrite magnetic pigment is added to the liquid and stirred for 50 minutes until homogeneous. The mixture is then ground twice to form beads with a particle size of 0.8-1.0 mm. After grinding, the mixture is filtered through a 4 μm pore size filter to obtain the final product.

[0044] Example 3

[0045] This embodiment provides a UV-LED curable gravure printing ink. The composition and ratio of the UV-LED curable gravure printing ink are as follows: 15wt% polyester acrylate 1, 10wt% polyester acrylate 3, 11wt% trimethylolpropane triacrylate ethoxylate, 11wt% N-acryloylmorpholine, 8wt% trifunctional acrylate containing acidic groups, 35wt% ferrite, 3wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 3.2wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.3wt% photosensitizer, 3wt% copolymer containing acidic groups, and 0.5wt% defoamer.

[0046] The aforementioned UV-LED curable gravure printing ink is prepared using the following process steps:

[0047] Under natural light conditions, the monomers are mixed and stirred until a clear, transparent liquid is obtained. The prepolymer is slowly added and stirred for 20 minutes until homogeneous. The dispersant and defoamer are added to the liquid and stirred for 20 minutes until homogeneous. The photoinitiator and photosensitizer are added to the liquid and stirred for 30 minutes until homogeneous. The ferrite magnetic pigment is added to the liquid and stirred for 50 minutes until homogeneous. The mixture is then ground twice to form beads with a particle size of 0.8-1.0 mm. After grinding, the mixture is filtered through a 4 μm pore size filter to obtain the final product.

[0048] Example 4

[0049] This embodiment provides a UV-LED curable gravure printing ink. The composition and ratio of the UV-LED curable gravure printing ink are as follows: 10wt% polyester acrylate 1, 10wt% polyester acrylate 3, 30wt% trimethylolpropane triacrylate ethoxylate, 29wt% N-acryloylmorpholine, 1wt% trifunctional acrylate containing acidic groups, 15.1wt% ferrite, 1.5wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1.5wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.4wt% photosensitizer, 0.5wt% copolymer containing acidic groups, and 1wt% defoamer.

[0050] The aforementioned UV-LED curable gravure printing ink is prepared using the following process steps:

[0051] Under natural light conditions, the monomers are mixed and stirred until a clear, transparent liquid is obtained. The prepolymer is slowly added and stirred for 20 minutes until homogeneous. The dispersant and defoamer are added to the liquid and stirred for 20 minutes until homogeneous. The photoinitiator and photosensitizer are added to the liquid and stirred for 30 minutes until homogeneous. The ferrite magnetic pigment is added to the liquid and stirred for 50 minutes until homogeneous. The mixture is then ground twice to form beads with a particle size of 0.8-1.0 mm. After grinding, the mixture is filtered through a 4 μm pore size filter to obtain the final product.

[0052] Example 5

[0053] This embodiment provides a UV-LED curable gravure printing ink, the composition and ratio of which are as follows: 20wt% polyester acrylate 1, 20wt% polyester acrylate 3, 19wt% trimethylolpropane triacrylate ethoxylate, 18wt% N-acryloylmorpholine, 2wt% trifunctional acrylate containing acidic groups, 6.3wt% ferrite, 4wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 4wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.2wt% photosensitizer, 6wt% copolymer containing acidic groups, and 0.5wt% defoamer.

[0054] The aforementioned UV-LED curable gravure printing ink is prepared using the following process steps:

[0055] Under natural light conditions, the monomers are mixed and stirred until a clear, transparent liquid is obtained. The prepolymer is slowly added and stirred for 20 minutes until homogeneous. The dispersant and defoamer are added to the liquid and stirred for 20 minutes until homogeneous. The photoinitiator and photosensitizer are added to the liquid and stirred for 30 minutes until homogeneous. The ferrite magnetic pigment is added to the liquid and stirred for 50 minutes until homogeneous. The mixture is then ground twice to form beads with a particle size of 0.8-1.0 mm. After grinding, the mixture is filtered through a 4 μm pore size filter to obtain the final product.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 1 is that no dispersant was added, while the other conditions are the same as in Example 1.

[0058] Comparative Example 2

[0059] The difference between this comparative example and Example 1 is that no photosensitizer was added, while the other conditions were the same as in Example 1.

[0060] Comparative Example 3

[0061] The difference between this comparative example and Example 2 is that the composition and ratio of the UV-LED curable gravure printing ink are as follows: 5.5 wt% polyester acrylate 2, 5.5 wt% polyester acrylate 3, 15.1 wt% cyclotrimethylolpropane methyl acetal acrylate, 14.2 wt% monofunctional acrylate, 14.2 wt% trifunctional acrylate containing acidic groups, 36 wt% ferrite, 3 wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 3 wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 0.2 wt% photosensitizer, 3 wt% copolymer containing acidic groups, and 0.5 wt% defoamer. Other conditions are the same as in Example 2.

[0062] Comparative Example 4

[0063] The difference between this comparative example and Example 1 is that no monomer containing hydroxyl or / and acidic groups is added. That is, the trifunctional acrylate containing acidic groups in Example 1 is replaced with the same amount of N-acryloylmorpholine, and other conditions are the same as in Example 1.

[0064] Comparative Example 5

[0065] The difference between this comparative example and Example 1 is that all monomers used are monomers containing hydroxyl groups and / or acidic groups. That is, the trimethylolpropane triacrylate and N-acryloylmorpholine in Example 1 are replaced with the same amount of trifunctional acrylates containing acidic groups. Other conditions are the same as in Example 1.

[0066] Comparative Example 6

[0067] The difference between this comparative example and Example 1 is that the cleavage-type acylphosphine oxide (3 wt% ethyl 2,4,6-trimethylbenzoylphenylphosphonate + 3 wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) is replaced with 6 wt% isopropylthioxanthone photoinitiator (IGM Corporation, ITX), while other conditions are the same as in Example 1.

[0068] Comparative Example 7

[0069] The difference between this comparative example and Example 1 is that the photosensitizer with benzylidene ketone free groups (1208, Shanghai Lianzhi) was replaced with a tertiary amine photosensitizer (IGM, EDB), while the other conditions were the same as in Example 1.

[0070] Comparative Example 8

[0071] The difference between this comparative example and Example 1 is that the photosensitizer with benzyl ketone free groups (1208, Shanghai Lianzhi) was replaced with 4,4'-bis(N,N-dimethylamino)benzophenone photosensitizer (milchone, CAS: 90-94-8), while other conditions were the same as in Example 1.

[0072] Test Example 1

[0073] The UV-LED inks prepared in the examples and comparative examples were printed onto PET films using a printing press to create specific images with a thickness of 10 μm and a width of 2 mm. The images were then cured using Heraeus LED curing equipment. Simultaneously, the ink properties (viscosity, drying speed, adhesion) were tested using the following methods:

[0074] Viscosity test: The inks in the examples and comparative examples were prepared according to the specified ratios, and their viscosity was measured using a rotational viscometer;

[0075] Drying speed test: The inks used in the examples and comparative examples were printed onto a PET pre-coated film using a small gravure proofing machine. The emission spectrum of the LED light source was 385nm, and the light intensity was approximately 10W / cm². 2 The power is 1.3kW, and the dimming range is 10%-100%. Curing is performed at 50% power. The drying speed is measured when the cured coating shows no scratches when lightly scratched with a fingernail.

[0076] Adhesion test: For the cured coatings of the examples and comparative examples, the peel strength test was conducted using 600# tape. No significant peeling was observed at a 90° peel angle. The adhesion strength was represented by the ratio of the area of ​​the unremoved coating to the printed area; a larger ratio indicates stronger adhesion. The test results are shown in Table 1.

[0077] Table 1

[0078]

[0079]

[0080] As can be seen from the results in Table 1, Examples 1-5, when printed on PET pre-coated surfaces using rotary gravure printing, exhibit viscosity, drying speed, and adhesion that meet the gravure printing requirements for plastic substrates. However, Comparative Examples 1-7 show significantly worse results compared to Examples 1-5. Specifically, tests indicate that the inks in Comparative Examples 1-7 do not provide good ink retention, curing speed, and adhesion, and therefore cannot improve the printing performance of the inks. Specifically, in Comparative Example 1, no dispersant was added, resulting in increased ink viscosity, slower curing speed, and poorer printing appearance; in Comparative Example 2, no photosensitizer was added, leading to slower ink curing speed; in Comparative Example 3, the prepolymer / monomer ratio was too low, resulting in decreased ink viscosity but slower drying speed and poorer adhesion; in Comparative Example 4, no monomers containing hydroxyl or acidic groups were added, resulting in poor ink adhesion; in Comparative Example 5, all monomers containing hydroxyl or acidic groups were used, leading to increased ink viscosity and decreased curing speed; in Comparative Example 6, no pyrolytic phosphine oxide type photoinitiator was used, and photosensitizers containing benzylidene ketone radicals could not form a combined structure-activity relationship with it, resulting in a decreased curing speed; in Comparative Examples 7 and 8, no photosensitizers containing benzylidene ketone radicals were added, and they could not form a combined structure-activity relationship with pyrolytic phosphine oxide type photoinitiators, resulting in a decreased curing speed.

[0081] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A UV-LED-curable intaglio printing ink, characterized in that The raw materials for preparing the UV-LED curable gravure printing ink include: 20-40 wt% prepolymer, 20-60 wt% monomer, 2-50 wt% pigment, 3-8 wt% photoinitiator, 0.2-0.4 wt% photosensitizer, 0.5-6 wt% dispersant and 0.5-1 wt% defoamer. Among the monomers, monomers containing hydroxyl and / or acidic groups account for 1-10 wt% of the total raw material mass of the ink. The photoinitiator is a pyrolytic acylphosphine oxide, and the photosensitizer is a photosensitizer with benzylidene ketone free groups.

2. The UV-LED-curable intaglio printing ink according to claim 1, characterized in that The raw materials for preparing the UV-LED curable gravure printing ink include: 25 wt% prepolymer, 30 wt% monomer, 35 wt% pigment, 6.2 wt% photoinitiator, 0.3 wt% photosensitizer, 3 wt% dispersant and 0.5 wt% defoamer, wherein monomers containing hydroxyl or / and acidic groups account for 8 wt% of the total raw material mass of the ink.

3. The UV-LED-curing intaglio printing ink according to claim 1 or 2, characterized in that The prepolymer is at least one of polyurethane acrylate, polyester acrylate, and polyether acrylate; And / or, the monomers that do not contain hydroxyl or / and acidic groups are at least one of neopentyl glycol diacrylate, dipropylene glycol diacrylate, diethylene glycol diacrylate, cyclotrimethylolpropane methyl acetal acrylate, acryloylmorpholine, ethoxylated trimethylolpropane triacrylate, and isobornyl acrylate.

4. The UV-LED-curable intaglio printing ink according to any one of claims 1 to 3, characterized in that The mass ratio of the prepolymer to the monomer is 1.0:(0.8-3.0); And / or, the pigment is a magnetic pigment.

5. The UV-LED-curable intaglio printing ink according to claim 4, characterized in that The magnetic pigment is at least one of iron, cobalt, nickel, or an alloy composed of at least two of the elements selected from iron, cobalt, and nickel, iron oxide, and rare earth elements.

6. The UV-LED-curable intaglio printing ink according to any one of claims 1 to 5, characterized in that The cleavage-type acylphosphine oxide is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, and ethyl 2,4,6-trimethylbenzoylphenylphosphine acid.

7. The UV-LED curable gravure printing ink according to any one of claims 1-6, characterized in that, The dispersant is at least one of the following: a polymer copolymer containing pigment affinity groups, a mixture of a compound containing pigment affinity groups and organosilicon, ammonium polyacrylate, a high molecular weight block copolymer solution containing pigment affinity groups, an acrylate copolymer solution with alkaline pigment affinity groups, a copolymer having acidic groups, and an acrylate copolymer containing pigment affinity groups. And / or, the defoamer is Tego-920.

8. A method for preparing a UV-LED curable gravure printing ink, characterized in that, Used to prepare the UV-LED curable gravure printing ink according to any one of claims 1-7.

9. The preparation method according to claim 8, characterized in that, The preparation method includes: mixing the prepolymer and monomer under conditions without ultraviolet irradiation, then adding defoamer and dispersant and mixing, then adding photoinitiator and photosensitizer and mixing, and finally adding pigment and mixing to obtain a dispersion. The dispersion is then ground and filtered to obtain UV-LED curable gravure printing ink.

10. The application of the UV-LED curable gravure printing ink prepared by the method of any one of claims 1-7 or the UV-LED curable gravure printing ink of claim 8 or 9 in gravure printing on plastic substrates.

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