UV-LED curing offset printing ink as well as preparation method and application thereof

Abstract

The invention discloses UV-LED (Ultraviolet-Light Emitting Diode) curing offset printing ink, which is characterized by comprising the following components in parts by mass: 40 to 60 parts of oligomer; 10 to 30 parts of an active monomer; 5 to 15 parts of a photoinitiator; 20 to 50 parts of pigment filler; and 0.1-2 parts of an auxiliary agent. The invention also discloses a preparation method and application of the compound. The UV-LED curing offset printing ink disclosed by the invention is good in demulsibility, good in transferability, high in curing speed, low in odor and relatively good in adhesive force to gold and silver card paper.

Description

Technical Field

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

[0002] Offset printing is a planar printing method based on the principle of water-oil immiscibility. UV offset inks are widely used in high-end packaging printing due to their instant curing, high efficiency, high gloss, and excellent resistance. They are typically composed of photoinitiators, oligomers, reactive monomers, pigments, fillers, and additives.

[0003] Currently available UV offset printing inks mainly improve gloss and curing speed by using epoxy acrylate oligomers and TMPTA monomers.

[0004] However, in pursuit of high curing efficiency, these types of UV offset printing inks often use large amounts of small-molecule photoinitiators (such as benzophenones) and low-molecular-weight reactive monomers. These substances are easily released from the UV offset printing ink film after curing and migrate to the surface of packaged food, posing a potential health risk.

[0005] Furthermore, reducing the amount of photoinitiator in UV offset inks to decrease migration can lead to new problems such as incomplete curing of UV offset inks, sticky ink layers, and decreased abrasion resistance. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of this invention is to provide a UV-LED curable offset printing ink, its preparation method and its uses.

[0007] Compared with existing UV-LED curable offset inks, the UV-LED curable offset ink of the present invention has better demulsification, better transferability, and faster curing speed.

[0008] A UV-LED curable offset printing ink, comprising the following components by weight: Oligomers: 40-60 parts; Active monomer: 10-30 parts; Photoinitiator: 5-15 parts; Pigment filler: 20-50 parts; Additives: 0.1-2 parts; In a preferred embodiment of the present invention, the oligomer is any one or more of polyester acrylate, polyurethane acrylate, polyether acrylate, epoxy acrylate, chlorinated polyester acrylate, modified rosin acrylate, and amine modified acrylate.

[0009] A mixture of polyester acrylate resin and epoxy acrylate resin is preferred, with a mixing ratio of 20:40-10:12.

[0010] In a preferred embodiment of the present invention, the active monomer is any one or more of the following: 1,4-hexanediol diacrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, cyclotrimethylolpropane methyl acetal acrylate, (n-ethoxylated)trimethylolpropane triacrylate, di(trimethylolpropane)triacrylate, glycerol acrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0011] Preferred materials include a mixture of trimethylolpropane triacrylate and dipropylene glycol diacrylate, a mixture of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, or trimethylolpropane triacrylate.

[0012] A more preferred mixing ratio is 5:3 for the mixture of trimethylolpropane triacrylate and dipropylene glycol diacrylate.

[0013] A more preferred mixing ratio is 9-10:5 for the mixture of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

[0014] In a preferred embodiment of the present invention, the photoinitiator is any one or more of the following: acylphosphooxide photoinitiator, α-hydroxyalkylphenyl ketone photoinitiator, benzoyl derivative photoinitiator, thioxanthone photoinitiator, or benzophenone and its derivatives photoinitiator.

[0015] In a preferred embodiment of the present invention, the acyl phosphorus oxide photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819).

[0016] In a preferred embodiment of the present invention, the α-hydroxyalkylphenyl ketone photoinitiator is any one or more of 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxy-cyclohexyl-phenyl methyl ketone (184), and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylpropanone (2959). In a preferred embodiment of the present invention, the α-aminoalkylphenyl ketone photoinitiator is any one or more of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (369), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (907), and 2-dimethylamino-2-benzyl-1-[4-(4-morpholino)phenyl]-1-butanone (379).

[0017] In a preferred embodiment of the present invention, the benzoyl derivative photoinitiator is α,α-dimethylbenzoyl ketal (BDK).

[0018] In a preferred embodiment of the present invention, the thioxanthone photoinitiator is any one or more of 2,4-diisopropylthioxanthone (ITX), 2-chlorothioxanthone (CTX), and 2,4-diethylthioxanthone (DETX).

[0019] In a preferred embodiment of the present invention, the benzophenone and its derivative photoinitiator is 4,4'-bis(dimethylamino)benzophenone (EMK).

[0020] Preferably, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 3-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-Hydroxy-cyclohexyl-phenyl ketone, 2,4-Diethylthioxanthone, Phenylacetylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Any one or more of 4,4'-bis(dimethylamino)benzophenone.

[0021] In a preferred embodiment of the present invention, the inorganic pigment is carbon black or titanium dioxide; the organic pigment is one or more of benzidine yellow, permanent yellow, golden red, lisol magenta, phthalocyanine blue, basic blue, phthalocyanine green, and carbazole violet.

[0022] In a preferred embodiment of the present invention, the filler is one or more of fumed silica, nano-calcium carbonate, talc, kaolin, and micro-wax powder.

[0023] In a preferred embodiment of the present invention, the additive is any one or more of a wetting and dispersing agent, a polymerization inhibitor, or a stabilizer; the dispersing agent is a high molecular weight block copolymer solution containing pigment affinity groups; and the polymerization inhibitor is one or more of phenols, aromatic amines, and aromatic hydroxynitro compounds.

[0024] In a preferred embodiment of the present invention, the UV-LED light source is one or more of 365nm, 385nm, or 395nm.

[0025] In a preferred embodiment of the present invention, it further includes 0-2 parts of a photosensitizer, wherein the photosensitizer is a tertiary amine photosensitizer.

[0026] A method for preparing a UV-LED curable offset printing ink includes the following steps: The photoinitiator and / or photosensitizer are completely dissolved in the active monomer. After complete dissolution and uniform stirring, the oligomer, pigments, fillers, and additives are added. The mixture is first stirred at a low speed (200-300 rpm), and then stirred at a high speed (800-1000 rpm) after the pigments and fillers are mixed into the resin mixture. The mixture is then ground on a three-roll mill with a grinding fineness of ≤10 μm. Once the standard is met, UV-LED offset printing white ink is obtained.

[0027] An application of a UV-LED curable offset printing ink, the application being a UV-LED curable offset printing ink suitable for gift box packaging.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: The UV-LED curable offset printing ink of the present invention has good deemulsification, good transferability, fast curing speed, low migration, low odor, and good adhesion to gold and silver cardboard. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, in the following descriptions, well-known structures and technologies are omitted to avoid unnecessarily obscuring the concept of the invention. Example 1

[0030]

[0031] The preparation method of Example 1 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide is completely dissolved in trimethylolpropane triacrylate and dipropylene glycol diacrylate. After complete dissolution and uniform mixing, polyester acrylate resin, epoxy acrylate resin, pigments and fillers, and GENORAD16 stabilizer are added. The mixture is first stirred at low speed (200-300 rpm), and then stirred at high speed (800-1000 rpm) after the pigments and fillers are mixed into the resin mixture until it is completely uniform. The mixture is then ground on a three-roll mill with a grinding fineness of ≤10 μm. Once the standard is met, UV-LED offset printing white ink is obtained. Example 2

[0032]

[0033] The preparation method of Example 2 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4-diethylthioxanthone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate. After complete dissolution and thorough mixing, the solution was dissolved in trimethylolpropane triacrylate. Then add polyester acrylate resin, epoxy acrylate resin, permanent yellow, benzidine yellow, talc, wax powder, Solsperse 39000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm). After the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until completely uniform. Then, grind the mixture on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, UV-LED offset printing yellow ink is obtained. Example 3

[0034]

[0035] The preparation method of Example 3 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, 4,4'-bis(dimethylamino)benzophenone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate. After the mixture is completely dissolved and stirred evenly, add polyester acrylate resin, epoxy acrylate resin, Lisol magenta, golden red, talc, wax powder, Solsperse 39000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm), and after the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until it is completely mixed evenly. Then, grind it on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, you will get UV-LED offset printing red ink. Example 4

[0036]

[0037] The preparation method of Example 4 is as follows: Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,4-diethylthioxanthone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate and dipentaerythritol hexaacrylate. After complete dissolution and thorough mixing, the solution was dissolved and stirred until homogeneous. Then add polyester acrylate resin, epoxy acrylate resin, carbon black, alkaline blue, talc powder, wax powder, Solsperse 24000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm), and after the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until completely uniform. Then, grind the mixture on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, UV-LED offset printing black ink is obtained. Example 5

[0038]

[0039] The preparation method of Example 5 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate and dipentaerythritol hexaacrylate. After the mixture is completely dissolved and stirred evenly, add polyester acrylate resin, epoxy acrylate resin, phthalocyanine blue, talc, wax powder, Solsperse 24000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm), and after the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until it is completely mixed evenly. Then, grind it on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, UV-LED offset printing blue ink is obtained.

[0040] Comparative Example 1

[0041] The preparation method of Comparative Example 1 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, 4,4'-bis(dimethylamino)benzophenone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate and (n-ethoxylated)trimethylolpropane triacrylate. After the mixture is completely dissolved and stirred evenly, add polyester acrylate resin, epoxy acrylate resin, Lisol magenta, golden red, talc, wax powder, Solsperse 39000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm), and after the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until it is completely mixed evenly. Then, grind it on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, you will get UV-LED offset printing red ink.

[0042] Comparative Example 2

[0043] The preparation method of Comparative Example 2 is as follows: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxy-cyclohexyl-phenyl ketone, and a tertiary amine photosensitizer were completely dissolved in trimethylolpropane triacrylate and dipentaerythritol hexaacrylate. After the mixture is completely dissolved and stirred evenly, add polyester acrylate resin, epoxy acrylate resin, permanent yellow, benzidine yellow, talc, wax powder, Solsperse 39000 dispersant, and GENORAD16 stabilizer. First, stir at low speed (200-300 rpm), and after the pigments and fillers are mixed into the resin mixture, stir at high speed (800-1000 rpm) until it is completely mixed evenly. Then, grind it on a three-roll mill. The grinding fineness should be ≤10um. After meeting the standard, you will get UV-LED offset printing yellow ink.

[0044] Comparative Example 3

[0045] The preparation method is the same as that of Comparative Example 2.

[0046] The UV-LED curable offset printing ink provided by this invention is suitable for sheet-fed or roll-fed printing. It primarily uses a UV-LED lamp, but can also be irradiated with a high-pressure mercury lamp or electron beam to instantly transform the ink from a liquid to a solid state, thereby achieving coloring on different paper substrates.

[0047] Viscosity testing: Brookfield CAP2000+L cone-plate viscometer (32℃ V:5R / V:15R); Emulsification test: Novomatics Lithotronic emulsifier was used; Solid content test: The solid content of the ink is tested according to GB / T 2793-1995 standard; Flowability test: Inclined plate flowability test (90° straight plate for 15 minutes); Adhesion test: YQM-1D ink viscosity tester (32℃, 800 rpm, 60 s); Ink viscosity test: Direct observation on the YQM-1D ink viscosity tester; Curing speed test: Using a 385nm UV-LED lamp, different curing energies were set, and the curing speed of the ink was observed (judged by whether the cured ink layer becomes sticky when pressed with a finger).

[0048] Adhesion test: 3M tape bonding method; Odor test: Subjective olfactory test method (cut the printed sample into 5cm*15cm pieces, immediately put them into a clean, odorless glass bottle and seal it. After placing it in a 50℃ oven for 1 hour, open the bottle stopper and smell the odor above the bottle mouth. It is divided into 1-5 levels, with level 1 being no odor, level 2 being a slight odor, level 3 being a noticeable odor, level 4 being a strong odor, and level 5 being an irritating odor). The test results of this invention are shown in the table below.

[0049] As shown in the test results in the table above: Viscosity and flowability are fundamental to the successful initiation and transfer of inks, and are important indicators for measuring ink transferability. Excessive viscosity and poor flowability generally result in poorer transferability. Viscosity should generally be controlled between 8 and 15 (32℃, 800 rpm, 60 seconds), and flowability should be controlled between 8 and 15 cm (90° straight plate, 15 minutes). In the examples, the viscosity was generally between 11 and 13 (except for white ink), and the flowability was ≥11 cm, indicating good transfer performance. In contrast, the viscosity of the comparative examples was generally above 17, and the flowability was ≤5 cm, indicating poor transfer performance.

[0050] Comparative Example 1 used 23 different active monomers from the present invention (15 parts of trimethylolpropane triacrylate + 8 parts of (n-ethoxylated)trimethylolpropane triacrylate), which resulted in a decrease in flowability (only 4 cm).

[0051] In Comparative Example 2, the active monomer content was only 5 parts, which was significantly low, but the oligomer content was as high as 58 parts (45 parts polyester acrylate + 8 parts epoxy acrylate + 5 parts dipentaerythritol hexaacrylate), resulting in a high viscosity of 15.8.

[0052] In Comparative Example 3, there were 14 parts of active monomer (4 parts of trimethylolpropane triacrylate + 10 parts of dipentaerythritol hexaacrylate) and 50 parts of oligomer, but the proportion of high-functionality monomers was too high, which affected the adhesion.

[0053] The UV-LED offset printing ink provided by this invention has low odor (virtually no volatile organic compounds), fast curing speed, good fluidity, excellent anti-emulsification properties, and good adhesion after curing. While using excessive high-functionality monomers can increase the curing rate, it affects the ink's fluidity, thus impacting color development and adhesion.

[0054] In summary, the UV-LED curable offset printing ink and its preparation method provided by this invention can produce UV-LED curable offset printing ink with low odor, good demulsibility, good transferability, high strength, and high curing speed, which can meet the requirements of the packaging and printing industry.

[0055] The foregoing has shown and described the basic principles and main features of the invention and the advantages of the invention.

[0056] Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A UV-LED curable offset printing ink, characterized in that, Calculated by parts by mass, it includes the following components: Oligomers: 40-60 parts; Active monomer: 10-30 parts; Photoinitiator: 5-15 parts; Pigment and filler: 20-50 parts; Additives: 0.1-2 parts; The oligomer is any one or more of polyester acrylate, polyurethane acrylate, polyether acrylate, epoxy acrylate, chlorinated polyester acrylate, modified rosin acrylate, and amine modified acrylate. The active monomer is any one or more of the following: 1,4-hexanediol diacrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, diethylene glycol diacrylate, cyclotrimethylolpropane methyl acetal acrylate, (n-ethoxylated)trimethylolpropane triacrylate, di(trimethylolpropane) triacrylate, glycerol acrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. The photoinitiator is any one or more of the following: acylphosphine oxide photoinitiator, α-hydroxyalkylphenyl ketone photoinitiator, benzoyl derivative photoinitiator, thioxanthone photoinitiator, or benzophenone and its derivatives photoinitiator.

2. The UV-LED curable offset printing ink as described in claim 1, characterized in that, The oligomer is a mixture of polyester acrylate resin and epoxy acrylate resin in a mixing ratio of 20:40-10:

12.

3. The UV-LED curable offset printing ink as described in claim 1, characterized in that, The active monomer is a mixture of trimethylolpropane triacrylate and dipropylene glycol diacrylate, a mixture of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate, or trimethylolpropane triacrylate.

4. The UV-LED curable offset printing ink as described in claim 1, characterized in that, The acyl phosphorus oxide photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819). The α-hydroxyalkylphenyl ketone photoinitiator is any one or more of 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 1-hydroxy-cyclohexyl-phenyl methyl ketone (184), and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylpropanone (2959). In a preferred embodiment of the present invention, the α-aminoalkylphenyl ketone photoinitiator is any one or more of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (369), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (907), and 2-dimethylamino-2-benzyl-1-[4-(4-morpholino)phenyl]-1-butanone (379); The benzoyl derivative photoinitiator is α,α-dimethylbenzoyl ketal (BDK). The thioxanthone photoinitiator is any one or more of 2,4-diisopropylthioxanthone (ITX), 2-chlorothioxanthone (CTX), and 2,4-diethylthioxanthone (DETX); The photoinitiator of benzophenone and its derivatives is 4,4'-bis(dimethylamino)benzophenone (EMK).

5. The UV-LED curable offset printing ink as described in claim 4, characterized in that, The photoinitiator is: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-Hydroxy-cyclohexyl-phenyl ketone, 2,4-Diethylthioxanthone, Phenylacetylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Any one or more of 4,4'-bis(dimethylamino)benzophenone.

6. The UV-LED curable offset printing ink as described in claim 1, characterized in that, The inorganic pigment is carbon black or titanium dioxide; the organic pigment is one or more of the following: benzidine yellow, permanent yellow, golden red, lisol magenta, phthalocyanine blue, basic blue, phthalocyanine green, and carbazole violet. The filler is one or more of the following: fumed silica, nano-calcium carbonate, talc, kaolin, and micro-wax powder; The additive is any one or more of wetting and dispersing agents, polymerization inhibitors, or stabilizers. The dispersing agent is a high molecular weight block copolymer solution containing pigment affinity groups. The polymerization inhibitor is one or more of phenols, aromatic amines, and aromatic hydroxynitro compounds.

7. The UV-LED curable offset printing ink as described in claim 1, characterized in that, The UV-LED light source is one or more of 365nm, 385nm, or 395nm.

8. The UV-LED curable offset printing ink as described in claim 1, characterized in that, It also includes 0-2 parts of photosensitizer, wherein the photosensitizer is a tertiary amine photosensitizer.

9. A method for preparing a UV-LED curable offset printing ink according to any one of claims 1-8, characterized in that, Includes the following steps: The photoinitiator and / or photosensitizer are completely dissolved in the active monomer. After complete dissolution and uniform stirring, the oligomer, pigments, fillers, and additives are added. The mixture is first stirred at a low speed (200-300 rpm), and then stirred at a high speed (800-1000 rpm) after the pigments and fillers are mixed into the resin mixture. The mixture is then ground on a three-roll mill with a grinding fineness of ≤10 μm. Once the standard is met, UV-LED offset printing white ink is obtained.

10. An application of a UV-LED curable offset printing ink as described in any one of claims 1-8, characterized in that, The application is a UV-LED curable offset printing ink suitable for gift box packaging.

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