LED-cured black printing ink

Abstract

The present application belongs to the technical field of iron printing ink, and particularly relates to a LED curing iron printing black ink. The conventional UV iron printing ink system has poor wrapping property for high pigment carbon black, the dispersion of the high pigment carbon black in the ink system is poor, the color development property of the obtained ink coating is not excellent enough, and the hiding power is not good enough. In view of the above problems, the present application provides a LED curing iron printing black ink, which introduces hydroxyl, lactone and pyrone functional groups in the structure of the base resin, so that the base resin and the high pigment carbon black have more similar structures, the compatibility is better, the base resin can better wrap and wet the high pigment carbon black, so that the dispersion of the high pigment carbon black is better, the color development property and the hiding power of the obtained LED curing iron printing ink coating are better, and a remarkable technical effect is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of iron printing ink, and particularly relates to an LED curing iron printing black ink. BACKGROUND

[0002] Iron printing ink is widely used in various fields and has been widely applied in various fields, such as printing of food, thermos bottles, toys, cosmetic boxes and the like. Most of the traditional iron printing ink is solvent-based and is not environmentally friendly. Although water-based iron printing ink is relatively environmentally friendly, the efficiency is low, and the comprehensive performance such as adhesion and water resistance is not ideal.

[0003] The solvent-free UV iron printing ink has fast curing speed and high efficiency, and the obtained ink coating has excellent performance in adhesion, water resistance and the like. The conventional UV resin has small molecular weight and usually only contains oxygen-containing functional groups such as hydroxyl and carboxyl groups, and can only wet coarse pigments, and the pigment wrapping property is not good enough, the ink color is not bright enough, especially the medium-high pigment carbon black, which has large specific surface area and high oil absorption, and is not easy to disperse. Therefore, the carbon black must be ground and dispersed by using a special high molecular dispersant (for example, EFKA-4310 high molecular dispersant) before being added into the resin system. Even so, the color of the obtained slurry is not black enough, the hiding power is not good enough, and the dispersion uniformity is relatively poor, which further affects the adhesion between the ink and the substrate and the appearance of the ink, and satisfactory results cannot be obtained. SUMMARY

[0004] The existing problems are that the conventional UV iron printing ink system has poor wrapping property for high pigment carbon black, the dispersion of the high pigment carbon black in the ink system is not good, the color development property of the obtained ink coating is not excellent, and the hiding power is not good enough. In view of the above problems, the present application provides an LED curing iron printing black ink, which comprises the following components in parts by weight:

[0005]

[0006] The modified acrylic resin is obtained by free radical polymerization of 4-acryloylmorpholine, dicyclopentyl methacrylate and tetrahydro-6-(3-pentenyl)-2H-pyran-2-one.

[0007] Specifically, the preparation method of the hydroxyl-modified polyurethane acrylate comprises the following steps:

[0008] (1) diethylene glycol dimethacrylate and mercaptoethanol undergo thiol-ene click chemistry reaction, the double bonds of diethylene glycol dimethacrylate are all consumed by the thiol in the reaction system, and the product A is obtained after the reaction is completed;

[0009] (2) the product A reacts with isophorone diisocyanate, the hydroxyl group of the product A reacts with the isocyanate group of the isophorone diisocyanate to form a urethane, after the reaction is completed, the isocyanate group in the reaction system is reduced to half of the original, after the reaction is completed, the product B is obtained, then the product B reacts with pentaerythritol triacrylate, the isocyanate group of the product B reacts with the hydroxyl group of the pentaerythritol triacrylate to form a urethane, after the reaction is completed, the isocyanate group in the reaction system is completely consumed, after the reaction is completed, the product C is obtained;

[0010] (3) the product C reacts with mercaptobutanol through thiol-ene click chemistry, the molar ratio of the double bond to the hydroxyl group in the reaction system is 1-2:1, after the reaction is completed, the carboxyl-modified polyurethane acrylate is obtained.

[0011] Specifically, the preparation method of the modified acrylic resin comprises the following steps:

[0012] (1) at room temperature, 4-acryloylmorpholine, 5-hydroxy-8-deca-ene acid-6-lactone, 6-pentyl-4-alkenyl-2-ketone, azobisisobutyronitrile and dioxane are uniformly mixed, the molar ratio of the 4-acryloylmorpholine to the 5-hydroxy-8-deca-ene acid-6-lactone and the 6-pentyl-4-alkenyl-2-ketone is 3:1:3, the addition amount of the azobisisobutyronitrile is 0.5% of the total weight of the polymerization monomers, the mass ratio of the 4-acryloylmorpholine to the dioxane is 1:9, then the reaction system is deoxygenated, and the temperature of the reaction system is raised to 70°C, the reaction is monitored by FTIR, the reaction is stirred until the double bond absorption peak in the reaction system disappears on the infrared spectrum, the reaction is completed, and the solvent is removed by reduced pressure distillation to obtain a solid product;

[0013] (2) after the solid product obtained in step (1) is washed with n-hexane, the solvent is removed by reduced pressure distillation to obtain the modified acrylic resin.

[0014] Specifically, the active monomer includes at least one of HDDA, PET4A and TPGDA.

[0015] Specifically, the high pigment carbon black includes at least one of Columbia (Bora) carbon black Raven 5000 Ultra III, Raven 5000 Ultra II, Raven 7000 and Raven 3500.

[0016] Specifically, the type of the photoinitiator is not particularly limited, and any photoinitiator capable of realizing the free radical photopolymerization of the ink system in the art can be used, preferably a free radical photoinitiator, and optionally the photoinitiator includes at least one of 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethyl benzoyl diphenyl phosphate and 4-chlorobenzophenone.

[0017] Specifically, the auxiliary agent comprises the following components in parts by weight:

[0018] a leveling agent 0.2-0.6 parts;

[0019] a dispersing agent 0.5-1.5 parts;

[0020] a defoaming agent 0.1-0.5 parts.

[0021] Specifically, the type of the leveling agent is not particularly limited, and any leveling agent used in a conventional UV ink system can be used, and a silicone leveling agent is preferred.

[0022] Specifically, the type of the defoaming agent is not particularly limited, and any defoaming agent used in a conventional UV ink system can be used, and a silicone defoaming agent or a polyether defoaming agent is preferred.

[0023] Specifically, the dispersing agent is a high molecular dispersing agent.

[0024] Specifically, 10-15 parts by weight of a filler is further included.

[0025] Specifically, the preparation method of the LED curing printing ink is as follows:

[0026] According to the formula amount, the raw materials are mixed at 40-50 DEG C, and then the temperature of the mixture is cooled to room temperature, and after uniform stirring and dispersion, the mixture is put into a grinding machine to grind to the required particle size.

[0027] The present application has the following beneficial effects:

[0028] (1) The LED curing printing ink obtained by the present application has better hiding power and color development;

[0029] (2) The present application introduces hydroxyl, lactone and pyrone functional groups in the structure of the base resin, so that the base resin has more similar structures with high pigment carbon black, and the compatibility is better, the base resin can better wrap and wet the high pigment carbon black, so that the dispersibility of the high pigment carbon black is better, and the color development and hiding power of the obtained LED curing printing ink coating are better;

[0030] (3) The present application finds through experiments that although the introduction of pyrone structure into the iron printing ink base resin can improve the color development and hiding power of the iron printing ink coating, not all pyrone derivatives can achieve satisfactory results. For example, the introduction of pyrone by 6-pentyl-4-enyloxy-2-ketone can indeed improve the color development and hiding power of the obtained ink coating, but it is difficult to achieve comparable technical effects by using pyrone derivatives containing long carbon chains, such as 6-[(Z)-non-4-enyl]oxan-2-one. The reason is that the steric hindrance effect of long carbon chain affects the beneficial interaction between pyrone and pigment carbon black, and further affects the wrapping of the base resin on the pigment carbon black. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 : Effect photos of color development and hiding power of the iron printing ink coating obtained in Example 1.

[0032] Figure 2 : Effect photos of color development and hiding power of the iron printing ink coating obtained in Comparative Example 1.

[0033] Figure 3 : Effect photos of color development and hiding power of the iron printing ink coating obtained in Comparative Example 2.

[0034] Figure 4 : Effect photos of color development and hiding power of the iron printing ink coating obtained in Comparative Example 3.

[0035] Figure 5 : Effect photos of color development and hiding power of the iron printing ink coating obtained in Comparative Example 4. DETAILED DESCRIPTION

[0036] The present application will be described in detail below in combination with examples. It should be understood that the following examples are only illustrative of the embodiments of the present application, and are not a limitation on the scope of the present application.

[0037] The hydroxyl-modified polyurethane acrylate used in the following examples of the present application is prepared according to the following steps:

[0038] S1: At room temperature, diethylene glycol dimethacrylate, photoinitiator 1173 and toluene are uniformly mixed, and then the temperature of the reaction system is raised to 50℃ to obtain a first mixed solution; the mass ratio of diethylene glycol dimethacrylate to photoinitiator 1173 is 23.2:0.04; the mass-volume ratio of diethylene glycol dimethacrylate to toluene is 3.82:7;

[0039] S2: continuously adding mercaptoethanol into the first mixed solution under inert gas protection, stirring and irradiating with LED lamp, monitoring the reaction by FTIR, until the absorption peak of double bond in the reaction system disappears in the infrared spectrum, the reaction is completed, stop adding, removing the solvent by distillation under reduced pressure, obtaining product A;

[0040] S3: mixing isophorone diisocyanate, dibutyl tin dilaurate and tetrahydrofuran uniformly at room temperature, then increasing the temperature of the reaction system to 70℃, obtaining the second mixed solution; the mass ratio of isophorone diisocyanate to dibutyl tin dilaurate is 14.3:0.02; the mass-volume ratio of isophorone diisocyanate to tetrahydrofuran is 3.02:6;

[0041] S4: continuously adding the product A into the second mixed solution under inert gas protection, monitoring the reaction by FTIR while stirring, continuously stirring at 70℃ until the absorption peak of isocyanate in the reaction system is reduced to half of the original in the infrared spectrum, stopping adding the product A, then adding hydroquinone into the reaction system, the adding amount of hydroquinone is 0.5% of the mass of the second mixed solution, continuously adding pentaerythritol triacrylate at the same time, stirring at 70℃ until the absorption peak of isocyanate in the reaction system disappears in the infrared spectrum, stopping adding, the reaction is completed, removing the solvent by distillation under reduced pressure, obtaining colorless viscous liquid;

[0042] S5: mixing the obtained colorless viscous liquid, photoinitiator 1173 and toluene uniformly at room temperature, the mass ratio of the colorless viscous liquid to photoinitiator 1173 and toluene is 20:1:60, then increasing the temperature of the reaction system to 50℃, adding mercaptobutanol into the reaction system under inert gas protection, the mass ratio of mercaptobutanol to colorless viscous liquid is 7:20.1 (so that the double bond in the reaction system is excessive relative to mercapto), then stirring and irradiating with LED lamp, monitoring the reaction by FTIR, stirring until the absorption peak of mercapto in the reaction system disappears in the infrared spectrum, the reaction is completed, removing the solvent by distillation under reduced pressure, obtaining hydroxyl modified polyurethane acrylate.

[0043] The preparation method of the modified acrylic resin used in the following examples of the application is as follows:

[0044] (1) 4-acryloylmorpholine, 5-hydroxy-8-deca-ene acid-6-lactone (CAS: 68959-28-4), 6-pentyl-4-alkenoxan-2-ketone (CAS: 74585-00-5), brand: Iodine, product number: P17017949), azobisisobutyronitrile, dioxane were mixed uniformly at room temperature, the molar ratio of 4-acryloylmorpholine to 5-hydroxy-8-deca-ene acid-6-lactone, 6-pentyl-4-alkenoxan-2-ketone was 3:1:3, the addition amount of azobisisobutyronitrile was 0.5% of the total weight of the polymer monomers, the mass ratio of 4-acryloylmorpholine to dioxane was 1:9, then the reaction system was deoxygenated, and the temperature of the reaction system was raised to 70 DEG C, FTIR was used to monitor the progress of the reaction, and the reaction was stopped when the double bond absorption peak in the reaction system disappeared on the infrared spectrum, and the solvent was removed by vacuum distillation, to obtain a solid product;

[0045] (2) After the solid product obtained in step (1) was washed with n-hexane, the solvent was removed by vacuum distillation to obtain a modified acrylic resin.

[0046] The photoinitiator used in the following examples of the application is 1-hydroxycyclohexyl phenyl ketone.

[0047] The leveling agent used in the following examples of the application is BYK361N.

[0048] The dispersing agent used in the following examples of the application is a high molecular dispersing agent, Evonik EFKA-4310 dispersing agent.

[0049] The defoaming agent used in the following examples of the application is BYK1797.

[0050] The filler used in the following examples of the application is talc, preferably, the average particle size can be at least one of 1500 mesh talc, 3000 mesh talc, 5000 mesh talc, and the average particle size of the talc used in the following examples of the application is 1500 mesh, which is purchased from Foshan Shunde Bozhen Chemical Co., Ltd.

[0051] The high pigment carbon black used in the following examples of the application is Columbia (Bora) carbon black Raven5000Ultra III.

[0052] The structural formula of 6-pentyl-4-alkenoxan-2-ketone used in the following examples of the application is as follows:

[0053]

[0054] The structural formula of 6-[(Z)-non-4-enyl]oxan-2-one used in the comparative example of the application is as follows:

[0055]

[0056] Example 1

[0057] An LED-cured black printing ink, in parts by weight, having the following composition:

[0058]

[0059] Example 2

[0060] An LED-cured black printing ink, in parts by weight, having the following composition:

[0061]

[0062]

[0063] Example 3

[0064] An LED-cured black printing ink, in parts by weight, having the following composition:

[0065] Example 4

[0066] An LED-cured black printing ink, in parts by weight, having the following composition:

[0067] Example 5

[0068] An LED-cured black printing ink, in parts by weight, having the following composition:

[0069]

[0070]

[0071] Comparative Example 1 is the same as Example 1 except that Comparative Example 1 uses the same weight parts of an unmodified conventional acrylic resin, DeGussa LP66 / 02N, instead of the modified acrylic resin in Example 1.

[0072] Comparative Example 2 is the same as Example 1 except that the modified acrylic resin in Comparative Example 2 is prepared as follows:

[0073] (1) 4-acryloylmorpholine, 5-hydroxy-8-deca-ene acid-6-lactone, azobisisobutyronitrile, dioxane were mixed uniformly at room temperature, the molar ratio of 4-acryloylmorpholine to 5-hydroxy-8-deca-ene acid-6-lactone was 1:1, the added amount of azobisisobutyronitrile was 0.5% of the total weight of the polymerization monomers, the mass ratio of 4-acryloylmorpholine to dioxane was 1:9, then the reaction system was deoxygenated, and the temperature of the reaction system was raised to 70°C, the reaction was monitored by FTIR, and the reaction was stopped when the double bond absorption peak in the reaction system disappeared in the infrared spectrum, then the solvent was removed by vacuum distillation, and a solid product was obtained;

[0074] (2) After the solid product obtained in step (1) was washed with n-hexane, the solvent was removed by vacuum distillation, and a modified acrylic resin was obtained.

[0075] Comparative Example 3 was the same as Example 1, except that the preparation method of the modified acrylic resin in Comparative Example 3 was as follows:

[0076] (1) 4-acryloylmorpholine, dicyclopentyl methacrylate, 6-pentyl-4-enoxyl-2-ketone, azobisisobutyronitrile, dioxane were mixed uniformly at room temperature, the molar ratio of 4-acryloylmorpholine to dicyclopentyl methacrylate, tetrahydro-6-(3-pentenyl)-2H-pyran-2-ketone was 3:1:3, the added amount of azobisisobutyronitrile was 0.5% of the total weight of the polymerization monomers, the mass ratio of 4-acryloylmorpholine to dioxane was 1:9, then the reaction system was deoxygenated, and the temperature of the reaction system was raised to 70°C, the reaction was monitored by FTIR, and the reaction was stopped when the double bond absorption peak in the reaction system disappeared in the infrared spectrum, then the solvent was removed by vacuum distillation, and a solid product was obtained;

[0077] (2) After the solid product obtained in step (1) was washed with n-hexane, the solvent was removed by vacuum distillation, and a modified acrylic resin was obtained.

[0078] Comparative Example 4 was the same as Example 1, except that the preparation method of the modified acrylic resin in Comparative Example 4 was as follows:

[0079] (1) at room temperature, 4-acryloylmorpholine, 5-hydroxy-8-deca-6- lactone, 6-[(Z)-non-4-enyl]oxan-2-one (CAS: 934298-76-7, brand: Aldrich, product number: P17423110), azobisisobutyronitrile, dioxane were mixed uniformly, the molar ratio of 4-acryloylmorpholine to 5-hydroxy-8-deca-6-lactone, 6-[(Z)-non-4-enyl]oxan-2-one was 3:1:3, the addition amount of azobisisobutyronitrile was 0.5% of the total weight of the polymerized monomers, the mass ratio of 4-acryloylmorpholine to dioxane was 1:9, then the reaction system was deoxygenated, and the temperature of the reaction system was raised to 70°C, the reaction was monitored by FTIR, and the reaction was stopped when the double bond absorption peak in the reaction system disappeared in the infrared spectrum, and the solvent was removed by reduced pressure distillation, to obtain a solid product;

[0080] (2) After the solid product obtained in step (1) was washed with n-hexane, the solvent was removed by reduced pressure distillation, to obtain a modified acrylic resin.

[0081] Performance test

[0082] The examples and comparative examples of the present application were mixed according to the corresponding formula amount at 50°C, and then the temperature of the mixture was cooled to room temperature, and after stirring and dispersing uniformly, it was put into a grinding machine to grind to an average particle size of 1 μm, to obtain an ink coating. Then the ink obtained in the examples and comparative examples was tested for related performance under the same photocuring conditions, and the specific test results are shown in Table 1. The color development of the ink obtained in Example 1 is shown in the accompanying drawing Figure 1 , the color development of the ink obtained in Comparative Example 1 is shown in the accompanying drawing Figure 2 , the color development of the ink obtained in Comparative Example 2 is shown in the accompanying drawing Figure 3 , the color development of the ink obtained in Comparative Example 3 is shown in the accompanying drawing Figure 4 , the color development of the ink obtained in Comparative Example 4 is shown in the accompanying drawing Figure 5 , and it can be seen from the drawings that the color development of the ink obtained in Example 1 is better, and the color of the iron printing ink coating is darker, blacker and brighter.

[0083] Ink coating flexibility: 180° folding observation of bursting.

[0084] Ink coating adhesion was determined according to GB / T9286-1998, ISO2409:1992 method.

[0085] Ink coating hiding power: the coating was applied on the surface of PET film material with a thickness of 10 μm, the ability to cover the white dots was observed.

[0086] Impact resistance of ink coating: falling dart impact

[0087] Performance tests were printed on tin except for hiding power which was printed on PET. The LED cured thickness of the ink coating was 10 μm.

[0088] Table 1

[0089] Test item Impact resistance (cm) Adhesion (grade) Flexibility Hiding power Example 1 64 0 No cracking No white spots visible Example 2 65 0 No cracking No white spots visible Example 3 70 0 No cracking No white spots visible Example 4 68 0 No cracking No white spots visible Example 5 71 0 No cracking No white spots visible Comparative Example 1 60 1 Cracking White spots visible, coating whitened Comparative Example 2 61 1 Slight cracking Few white spots, coating whitened Comparative Example 3 62 0 No cracking Few white spots Comparative Example 4 62 1 Slight cracking Few white spots

[0090] The above ideal embodiments according to the present application are used as an inspiration, and through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined by the scope of the claims.

Claims

1. A LED-cured flexo black ink, characterized in that, By weight parts, including the following ingredients: Hydroxyl modified polyurethane acrylate 40-70 parts; Modified acrylic resin 30-60 parts; Active monomer 20-40 parts; High pigment carbon black 4-6 parts; Photoinitiator 4-8 parts; Auxiliary 0.5-3 parts; The modified acrylic resin is obtained by free radical polymerization of 4-acryloyl morpholine, 5-hydroxy-8-deca-carbene acid-6-lactone, 6-pentyl-4-alkenyl-2-ketone; The preparation method of the modified acrylic resin comprises the following steps: (1) at room temperature, 4-acryloyl morpholine, 5-hydroxy-8-deca-carbene acid-6-lactone, 6-pentyl-4-alkenyl-2-ketone, azobisisobutyronitrile, dioxane are mixed uniformly, the molar ratio of 4-acryloyl morpholine, 5-hydroxy-8-deca-carbene acid-6-lactone, 6-pentyl-4-alkenyl-2-ketone is 3:1:3, the addition amount of azobisisobutyronitrile is 0.5% of the total weight of the polymer monomer, the mass ratio of 4-acryloyl morpholine to dioxane is 1:9, then the reaction system is deoxygenated, and the temperature of the reaction system is raised to 70℃, FTIR is used to monitor the progress of the reaction, the reaction is stirred until the double bond absorption peak in the reaction system disappears in the infrared spectrum, the reaction is completed, and the solvent is removed by reduced pressure distillation to obtain a solid product; (2) after washing the solid product obtained in step (1) with n-hexane, the solvent is removed by reduced pressure distillation to obtain the modified acrylic resin.

2. The LED-cured flexo black ink according to claim 1, wherein, The preparation method of the hydroxyl modified polyurethane acrylate comprises the following steps: (1) diethylene glycol dimethacrylate and mercaptoethanol undergo thiol-ene click chemistry reaction, the double bond of diethylene glycol dimethacrylate is completely consumed by the thiol in the reaction system, and product A is obtained after the reaction is completed; (2) product A reacts with isophorone diisocyanate, the hydroxyl group of product A reacts with the isocyanate group of isophorone diisocyanate to form a urethane, after the reaction is completed, the isocyanate group in the reaction system is reduced to half of the original, product B is obtained after the reaction is completed, and then product B reacts with pentaerythritol triacrylate, the isocyanate group of product B reacts with the hydroxyl group of pentaerythritol triacrylate to form a urethane, after the reaction is completed, the isocyanate group in the reaction system is completely consumed, and product C is obtained after the reaction is completed; (3) product C and mercapto butanol undergo thiol-ene click chemistry reaction, the molar ratio of double bond to hydroxyl group in the reaction system is 1-2:1, and the hydroxyl modified polyurethane acrylate is obtained after the reaction is completed.

3. The LED-cured flexo black ink according to claim 1, wherein, The high pigment carbon black includes at least one of Columbia carbon black Raven 5000 Ultra III, Raven 5000 Ultra II, Raven 7000, and Raven 3500.

4. The LED-cured flexo black ink according to claim 1, wherein, The photoinitiator is a free radical type photoinitiator.

5. The LED-cured flexo black ink according to claim 1, wherein, The auxiliary, by weight parts, includes the following ingredients: Leveling agent 0.2-0.6 parts; Dispersing agent 0.5-1.5 parts; Defoaming agent 0.1-0.5 parts.

6. The LED-cured flexo black ink according to claim 5, wherein, The leveling agent is a silicone leveling agent.

7. The LED-cured flexo black ink according to claim 5, wherein, The defoaming agent is a silicone defoaming agent.

8. The LED-cured flexo black ink according to claim 5, wherein, The dispersant is a high molecular dispersant.

9. The LED-cured flexo black ink according to claim 1, wherein, 10-15 parts by weight of a filler are also included.

10. A LED-cured flexographic black ink according to any one of claims 1 to 9, characterized in that, The preparation method is as follows: According to the formula amount, the raw materials are mixed at 40-50°C, and then the temperature of the mixture is cooled to room temperature. After stirring and uniformly dispersing, the mixture is put into a grinding machine to grind to the required particle size, and the product is obtained.

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