Dual-curing ink

Abstract

The invention relates to the technical field of ink, and provides dual-curing ink which comprises the following components in percentage by mass: isobornyl acrylate, 1, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate, 1, 2, 4 The high-temperature-resistant acrylic resin is prepared from 2, 6-hexanediol diacrylate, tetrahydrofurfuryl alcohol-based acrylate, vinyl caprolactam, 2-hydroxy-3-phenoxypropyl acrylate, triphenylphosphine oxide, methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-acetone, 2-isopropyl thioxanthone, methylated amino resin, toner, a dispersing agent, a flatting agent and an acid catalyst. A preliminary curing structure is formed by photocuring, and thermal curing ensures that places which cannot be irradiated by light can be completely cured, so that the applicability and the reliability of the ink are improved. Compared with ink with a single curing mode, multiple indexes such as hardness, adhesive force, curing shrinkage rate and glossiness of a coating using the dual-curing ink can be remarkably improved, so that various performance requirements required by glass products and the like are met.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and in particular to a dual-curing ink. Background Art

[0002] In recent years, with the development of digital printing technology, the printing speed, resolution, color accuracy and other performance of digital printing equipment have continued to improve. All walks of life are reforming the printing process. Compared with traditional screen printing, digital printing does not require plate making, the process is simple, the accuracy and resolution are high, which greatly improves production efficiency and shows great superiority.

[0003] While digital printing technology offers numerous advantages, the corresponding inks have not kept pace. This is particularly true for difficult-to-adhere substrates like glass, where product performance struggles to meet customer needs. This has limited digital printing in many applications. The primary reason is that the light-curing inks used require low viscosity. These are primarily based on monomers such as acrylates, which have a high double bond density and large shrinkage, resulting in poor adhesion to these substrates. To improve ink adhesion to difficult-to-adhere substrates like glass, dual-curing methods are often employed. There are various dual-curing methods, such as light-curing + moisture-curing and free radical-curing + cationic-curing. Light-curing + moisture-curing, as the ink readily cures with water vapor when exposed to air, carries a significant risk of printhead clogging. Free radical-curing + cationic-curing, as a new curing technology, has found widespread application in the photoresist field, but its application in pigmented systems is significantly limited. This is primarily due to the difficulty in stabilizing the ink in pigmented systems and the resulting tendency to cause printhead clogging. Furthermore, most current cationic initiators are photoacid-generating initiators, which are sensitive to alkali. This can easily lead to curing failure if the substrate is alkaline or if the coating on the substrate contains alkaline substances (such as amino-based baking varnishes). In view of this, the present invention proposes a dual-curing ink of photocuring + thermal curing. The principle is to introduce hydroxyl-containing oligomers and amino resins into the photocuring ink. After photocuring, high-temperature baking (150℃~180℃) is used. The amino resin will be cured and cross-linked with the hydroxyl group to improve properties such as adhesion and chemical resistance. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a dual-cure ink comprising the following components by weight:

[0005] Isobornyl acrylate 26%~53%

[0006] 1,6-hexanediol diacrylate 0%~25%

[0007] Tetrahydrofurfuryl acrylate 8%~12%

[0008] Vinyl caprolactam 0%~15%

[0009] 2-Hydroxy-3-phenoxypropyl acrylate 0%~20%

[0010] Triphenylphosphine oxide 2%~6%

[0011] Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone 1% to 5%

[0012] 2-Isopropylthioxanthone 0%~3%

[0013] Methylated amino resin 5%~15%

[0014] Toner 2% to 6%

[0015] Dispersant 0.5%~3%

[0016] Leveling agent 0.5%~1%

[0017] Acid catalyst 0% to 2%.

[0018] Preferably, the weight proportion of the methyl etherified amino resin is 10%.

[0019] Preferably, the mass proportion of 1,6-hexanediol diacrylate is 15%.

[0020] Preferably, the mass proportion of vinyl caprolactam is 5%.

[0021] Preferably, the mass proportion of 2-hydroxy-3-phenoxypropyl acrylate is 10%.

[0022] Preferably, the acid catalyst accounts for 1% by mass.

[0023] Furthermore, the toner is adjusted according to the desired color of the ink.

[0024] Furthermore, the toner used for the red ink is Lily PM-122, the toner used for the yellow ink is Lily PM-1503, the toner used for the blue ink is BASF D7110F, and the toner used for the black ink is Cabot REGAL 250R.

[0025] Furthermore, the preparation method of the ink is as follows: first, isobornyl acrylate, 1,6-hexanediol diacrylate, tetrahydrofurfuryl acrylate, vinyl caprolactam, 2-hydroxy-3-phenoxypropyl acrylate, triphenylphosphine oxide, methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, and 2-isopropylthioxanthone are added to a material tank and stirred to dissolve. After complete dissolution, color powder and dispersant are added while stirring, and the mixture is evenly dispersed at a speed of 800 r / min. After dispersion, the mixture is added to a sand mill, the sand mill speed is adjusted to 2000 r / min, and the mixture is ground for a certain period of time. The particle size is tested every half hour. When the ink particle size D99 is below 500 nm, the material is discharged, and then a methylated amino resin, a leveling agent, and an acid catalyst are added. After high-speed dispersion, the mixture is evenly dispersed and filtered to obtain the finished product.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Compared with the light curing + moisture curing and free radical curing + cationic curing methods, the dual curing method of light curing + thermal curing adopted in the present invention has a long open time and is insensitive to both acid and alkali, and is particularly suitable for some substrates that can withstand high temperatures, such as metallic glass. The light curing + thermal curing method allows the ink to form a preliminary solidified structure during the light curing stage, and then achieves secondary curing by heating, ensuring that even places that are not exposed to light can be completely cured, thereby improving the applicability and reliability of the ink. Compared with inks with a single curing method, the hardness, adhesion, curing shrinkage, glossiness and other indicators of the coating using this dual curing ink can be significantly improved, thereby meeting the various performance requirements required for glass products and the like. The improvement of these properties enables this ink to adapt to a wider range of application fields, especially in industrial applications requiring high stability and durability, the advantages of this ink are particularly obvious. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the technical solutions in the specific implementation methods of the present invention are clearly and completely described below to further illustrate the present invention. Obviously, the specific implementation methods described are only part of the implementation methods of the present invention, rather than all styles.

[0029] The dual-cure ink of the present invention comprises the following components by weight:

[0030] Isobornyl acrylate 26%~53%

[0031] 1,6-hexanediol diacrylate 0%~25%

[0032] Tetrahydrofurfuryl acrylate 8%~12%

[0033] Vinyl caprolactam 0%~15%

[0034] 2-Hydroxy-3-phenoxypropyl acrylate (Changxing 620-100 in this example) 0% to 20%

[0035] Triphenylphosphine oxide 2%~6%

[0036] Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone 1% to 5%

[0037] 2-Isopropylthioxanthone 0%~3%

[0038] Methyl etherified amino resin (in this example, CYMEL303LF) 5% to 15%

[0039] Toner 2% to 6%

[0040] Dispersant (BYK-9151 in this example) 0.5% to 3%

[0041] Leveling agent (BYK-333 in this example) 0.5% to 1%

[0042] Acid catalyst (NACURE 2500 in this embodiment) 0% to 2%.

[0043] Among them, the mass proportion of 1,6-hexanediol diacrylate is preferably 15%, the mass proportion of vinyl caprolactam is preferably 5%, the mass proportion of 2-hydroxy-3-phenoxypropyl acrylate is preferably 10%, and the mass proportion of the acid catalyst is preferably 1%.

[0044] The toner is selected according to the required color of the ink. For example, when preparing red ink, the toner used is Lily PM-122, when preparing yellow ink, the toner used is Lily PM-1503, when preparing blue ink, the toner used is BASF D7110F, and when preparing black ink, the toner used is Cabot REGAL 250R.

[0045] The ink is prepared as follows: isobornyl acrylate, 1,6-hexanediol diacrylate, tetrahydrofurfuryl acrylate, vinyl caprolactam, 2-hydroxy-3-phenoxypropyl acrylate, triphenylphosphine oxide, methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, and 2-isopropylthioxanthone are placed in a material tank and stirred to dissolve. After complete dissolution, the colorant and dispersant are added while stirring, and the mixture is evenly dispersed at a speed of 800 r / min. After dispersion, the mixture is added to a sand mill, the sand mill speed is adjusted to 2000 r / min, and the mixture is ground for a certain period of time. The particle size is tested every half hour. When the ink particle size D99 is below 500 nm, the material is discharged, and then a methylated amino resin, a leveling agent, and an acid catalyst are added. The mixture is evenly dispersed at high speed and filtered to obtain the finished product.

[0046] To determine the composition and optimal content of the dual-cure ink of the present invention, a comparative experiment was conducted using black inks with different compositions. The experiment involved printing a 10cm x 10cm area of sample on clean glass using a RICOH Gen6 flatbed UV printer and curing the prints. The samples were then tested for surface setting, adhesion, water boiling resistance, and surface hardness. The testing methods for various physical properties are as follows.

[0047] The surface dryness test method is: finger pressure method.

[0048] Dip a clean towel in an appropriate amount of anhydrous ethanol and carefully wipe your finger to remove grease, dust, and other substances that may affect the test results. Once your finger is completely dry, apply even, gentle pressure to the ink surface. Use moderate pressure to avoid applying too little to accurately determine ink dryness or applying too much pressure to damage the ink layer. Apply pressure to different areas of the sample to ensure reliable test results.

[0049] After each finger press, observe whether there is ink adhesion on your finger, and also pay attention to whether there are depressions, deformations, or fingerprint residue on the ink surface. If there is ink adhesion on your finger, it means that the ink has not yet dried and is in the initial dry state. If there is no ink adhesion on your finger, but there are depressions or obvious fingerprints on the ink surface, it means that the ink is partially dry but not fully cured, which is the surface dry state. If there is no ink adhesion on your finger and there are no obvious depressions or fingerprints on the ink surface, it means that the ink is completely dry and is in the actual dry state.

[0050] Adhesion test method: 100 grid method.

[0051] 1. Preparation:

[0052] Test sample preparation: Ensure the test sample surface is clean and flat, and the coating is completely dry. If there is dust, oil or other impurities on the surface, it will affect the accuracy of the test results.

[0053] Tool preparation: Prepare tools such as a scriber knife, a soft brush, 3M tape, and an eraser.

[0054] 2. Grid operation:

[0055] Place the test sample on a flat plate with sufficient rigidity to prevent deformation of the sample during the cross-cutting process.

[0056] Hold the handle of the multi-blade cutter and make the multi-blade cutter perpendicular to the sample plane. Cut with uniform pressure, steady and non-vibrating technique at a certain speed (usually 20mm / s to 50mm / s).

[0057] 3. Cleaning: Use a soft brush to gently brush forward and backward along the two diagonal lines of the grid pattern 5 times each to remove debris and other impurities in the grid area.

[0058] 4. Apply the tape: Apply the 3M tape evenly to the test area after the grid is crossed, and rub the tape vigorously with an eraser to increase the contact area and strength between the tape and the test area to ensure full contact between the tape and the coating.

[0059] 5. Tear off the tape: Grab one end of the tape and quickly tear it off vertically. Repeat the test at the same location at least twice.

[0060] 6. Observation and Assessment: Carefully observe the coating flaking within the test area. The test area is graded from 0 to 5 according to ISO standards, with higher grades indicating better adhesion. Grade 5: The cut edge is completely smooth, with no flaking. Grade 4: A small amount of coating flaking occurs at the intersection of the cuts, but the affected cross-cut area must not exceed 5%. Grade 3: The coating flaks at the intersection of the cuts and / or along the cut edges, with the affected cross-cut area significantly exceeding 5% but not exceeding 15%. Grade 2: The coating partially or completely flaks in large pieces along the cut edge, and / or partially or completely peels off at different locations on the grid, with the affected cross-cut area significantly exceeding 15% but not exceeding 35%. Grade 1: The coating flaks in large pieces along the cut edge, and / or some squares partially or completely peel off, with the affected cross-cut area significantly exceeding 35% but not exceeding 65%. Grade 0: The degree of flaking exceeds Grade 1.

[0061] Boiling water resistance test method:

[0062] Place the prepared sample in a constant temperature water bath, turn on the heating device, bring the water to a boil, and maintain the water temperature within the specified temperature range for one hour. After the test time is up, remove the sample and observe whether there are any blistering, cracking, shedding, discoloration, or loss of gloss on the surface.

[0063] Surface hardness test method:

[0064] 1. Test tool preparation:

[0065] Pencil sharpener: used to sharpen pencils into a specific shape. Generally, the pencil lead is required to be exposed about 3mm and sharpened into a cylindrical shape with a flat end surface without gaps and burrs.

[0066] 400-grit sandpaper: used to polish the pencil lead before testing to make its end surface smoother and flatter, ensuring the accuracy of the test.

[0067] Weight: 750g, used to apply a certain amount of pressure to the pencil during the test.

[0068] Test platform: The surface must be flat and hard, such as a glass or metal plate, to ensure the stability of the sample during the test.

[0069] 2. Sample preparation:

[0070] Surface treatment: Clean the surface of the sample to be tested, remove oil, dust and other impurities, and ensure that the surface is flat, without scratches or unevenness.

[0071] Fixing: Fix the specimen to the test platform to ensure that it does not move or shake during the test. You can use tools such as clamps and tape to fix it.

[0072] 3. Test steps:

[0073] Pencil placement: Fix the pencil on the test platform so that it is at a 45° angle to the sample surface, and the front end of the pencil lead lightly touches the sample surface.

[0074] Apply pressure: Place a weight on top of the pencil so that the pencil applies 750g of pressure to the sample surface.

[0075] Scratch the pencil: Push the pencil across the sample surface at a speed of about 1 cm / s for a length of about 10 mm.

[0076] Observation: After scratching the sample, observe whether there are any scratches on the surface. If there are no scratches, change to a pencil with a lower hardness and continue the test. If there are scratches, record the pencil hardness at that time, which is the surface hardness value of the sample.

[0077] The experimental results are:

[0078] Table 1 Composition and content data of Examples 1 to 6

[0079]

[0080] Table 2 Experimental results of Examples 1 to 6

[0081] physical properties Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Surface dryness Initial Initial Basic surface dry Basic surface dry Basic surface dry Initial Surface hardness H H H~2H 2H 2H 2H Adhesion 5 5 5 5 4 3 Boiling water for 1 hour No shedding No shedding No shedding No shedding Falling off Falling off

[0082] It can be seen from Examples 1 to 6 that:

[0083] As the amount of 1,6-hexanediol diacrylate increases, the surface drying property improves, but decreases after reaching a certain amount. This shows that the appropriate addition of multifunctional monomers such as 1,6-hexanediol diacrylate is beneficial to improving the degree of crosslinking and thus improving the surface drying property. However, with the increase of multifunctional monomers, the number of reactive sites increases, molecular chain entanglement occurs, and steric hindrance increases, which slows down the reaction rate. In addition, the surface drying performance deteriorates due to oxygen inhibition.

[0084] When the amount of 1,6-hexanediol diacrylate increases to a certain level, the adhesion decreases, which is closely related to the curing shrinkage.

[0085] With the increase of the amount of 1,6-hexanediol diacrylate, the boiling resistance becomes worse.

[0086] In summary: when the dosage of 1,6-hexanediol diacrylate is 15%, a good balance can be achieved in surface drying, adhesion, water boiling resistance and surface hardness.

[0087] Table 3 Composition and content data of Examples 7 to 10

[0088] Element Example 7 Example 8 Example 9 Example 10 Isobornyl acrylate 43％ 38％ 33％ 28％ 1,6-Hexanediol Diacrylate 15％ 15％ 15％ 15％ Tetrahydrofurfuryl acrylate 10％ 10％ 10％ 10％ Vinyl caprolactam 0 5％ 10％ 15％ 2-Hydroxy-3-phenoxypropyl acrylate (Changxing 620-100) 10％ 10％ 10％ 10％ Triphenylphosphine oxide 4％ 4％ 4％ 4％ Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone 3％ 3％ 3％ 3％ 2-Isopropylthioxanthone 1％ 1％ 1％ 1％ Methyl etherified amino resin (Allnex CYMEL303LF) 10％ 10％ 10％ 10％ Toner 2％ 2％ 2％ 2％ Dispersant (BYK-9151) 1.5％ 1.5％ 1.5％ 1.5％ Leveling agent (BYK-333) 0.5％ 0.5％ 0.5％ 0.5％

[0089] Table 4 Experimental results of Examples 7 to 10

[0090] physical properties Example 7 Example 8 Example 9 Example 10 Surface dryness Initial Basic surface dry Basic surface dry Basic surface dry Surface hardness 1 hour to 2 hours 2H 2H 2H Adhesion 5 5 5 5 Boiling water for 1 hour No shedding No shedding Falling off Falling off

[0091] It can be seen from Examples 6 to 10 that:

[0092] With the increase of vinyl caprolactam dosage, the surface drying performance gradually improves and the surface hardness increases, but the boiling water resistance gradually deteriorates. It is appropriate to add 5%.

[0093] Table 5 Composition and content data of Examples 11 to 15

[0094]

[0095] Table 6 Experimental results of Examples 11 to 15

[0096] physical properties Example 11 Example 12 Example 13 Example 14 Example 15 Surface dryness Initial Initial Basic surface dry Basic surface dry Basic surface dry Surface hardness H 1 hour to 2 hours 2H 2H~3H 3H Adhesion 5 5 5 5 5 Boiling water for 1 hour No shedding No shedding No shedding Falling off Falling off

[0097] It can be seen from Examples 11 to 15 that:

[0098] As the amount of 2-hydroxy-3-phenoxypropyl acrylate increases, the surface dryness gradually improves and the surface hardness increases, but the water boiling resistance gradually deteriorates. It is appropriate to add 10%. The reason is that as the amount of 2-hydroxy-3-phenoxypropyl acrylate increases, the cross-linking degree increases and the thermal curing shrinkage increases, resulting in subsequent deterioration of water boiling resistance.

[0099] Table 7 Composition and content data of Examples 16 to 20

[0100]

[0101] Table 8 Experimental results of Examples 16 to 20

[0102] physical properties Example 16 Example 17 Example 18 Example 19 Example 20 Surface dryness Basic surface dry Basic surface dry Basic surface dry Initial Initial Surface hardness H H~2H 2H 2H 2H~3H Adhesion 5 5 5 5 4 Boiling water for 1 hour No shedding No shedding No shedding Falling off Falling off

[0103] It can be seen from Examples 16 to 20 that:

[0104] As the amount of methyl ether amino resin increases, the surface dryness becomes worse and the surface hardness increases. Considering the balance between surface dryness and hardness, the appropriate amount of methyl ether amino resin is 10%.

[0105] Table 9 Composition and content data of Examples 21 to 24 and Comparative Examples 25 to 29

[0106]

[0107]

[0108] Table 10 Experimental results of Examples 21 to 24 and Comparative Examples 25 to 29

[0109]

[0110] As can be seen from Examples 21 to 24, as the amount of acid catalyst (NACURE 2500) increases, the surface hardness gradually increases. After reaching a certain amount, the surface hardness improvement slows down and the boiling resistance gradually deteriorates. Therefore, the appropriate amount of acid catalyst (NACURE 2500) is 1%.

[0111] It can be seen from Comparative Examples 25 to 27 that with the increase in the amount of curing agent BL3175, the surface hardness gradually increases and the surface drying performance gradually deteriorates. It can be seen from Comparative Examples 27 to 29 that with the increase in the amount of organotin drier T-12 catalyst, the surface hardness increases, but the increase in surface hardness is not obvious after exceeding 1%. Generally speaking, when using the system of curing agent BL3175 plus organotin drier T-12 catalyst, it is difficult to achieve a balance between adhesion, water boiling resistance and surface drying performance. Therefore, the present invention uses a system of methyl etherified amino resin plus 2-hydroxy-3-phenoxypropyl acrylate.

[0112] The above describes the main technical features and basic principles of the present invention and the related advantages. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the concept or essential characteristics of the present invention. Therefore, from all perspectives, the above-mentioned specific embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all changes that come within the meaning and range of equivalents of the claims be included within the present invention.

[0113] In addition, it should be understood that although this specification is described according to various implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A dual-curing ink, characterized in that: Calculated by mass, it contains the following components: Isobornyl acrylate 26%~53% 1,6-hexanediol diacrylate 0%~25% Tetrahydrofurfuryl acrylate 8%~12% Vinyl caprolactam 0%~15% 2-Hydroxy-3-phenoxypropyl acrylate 0%~20% Triphenylphosphine oxide 2%~6% Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone 1% to 5% 2-Isopropylthioxanthone 0%~3% Methylated amino resin 5%~15% Toner 2% to 6% Dispersant 0.5%~3% Leveling agent 0.5%~1% Acid catalyst 0% to 2%.

2. The dual-cure ink according to claim 1, characterized in that: The weight proportion of methyl etherified amino resin is 10%.

3. The dual-cure ink according to claim 1, characterized in that: The mass proportion of 1,6-hexanediol diacrylate is 15%.

4. The dual-cure ink according to claim 1, characterized in that: The mass proportion of vinyl caprolactam is 5%.

5. The dual-cure ink according to claim 1, characterized in that: The mass proportion of 2-hydroxy-3-phenoxypropyl acrylate is 10%.

6. The dual-cure ink according to claim 1, characterized in that: The acid catalyst accounts for 1% by mass.

7. The dual-cure ink according to claim 1, characterized in that: Toner is adjusted according to the required color of ink.

8. The dual-cure ink according to claim 7, characterized in that: The toner used for the red ink is Lily PM-122, the toner used for the yellow ink is Lily PM-1503, the toner used for the blue ink is BASF D7110F, and the toner used for the black ink is Cabot REGAL 250R.

9. The dual-cure ink according to claim 1, characterized in that: The preparation method of the ink comprises the following steps: firstly, adding isobornyl acrylate, 1,6-hexanediol diacrylate, tetrahydrofurfuryl acrylate, vinyl caprolactam, 2-hydroxy-3-phenoxypropyl acrylate, triphenylphosphine oxide, methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, and 2-isopropylthioxanthone into a material tank, stirring and dissolving the mixture; after the mixture is completely dissolved, adding color powder and dispersant while stirring, and uniformly dispersing the mixture at a speed of 800 r / min; after the mixture is dispersed, adding the mixture into a sand mill, adjusting the speed of the sand mill to 2000 r / min, grinding the mixture for a certain period of time, testing the particle size every half an hour, releasing the material when the ink particle size D99 is below 500 nm, adding methyl etherified amino resin, a leveling agent, and an acid catalyst, uniformly dispersing the mixture at high speed, and filtering the mixture to finally obtain a finished product.

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