An inkjet printing water-based UV ink and a preparation method thereof

Abstract

The present application relates to a kind of water-based UV inkjet printing UV ink and its preparation method, belong to the technical field of UV ink.A kind of water-based UV inkjet printing UV ink preparation method includes the following steps: after the dehydration of dihydric alcohol is placed in reaction kettle, MDI, HDI and organotin catalyst are stirred and reacted, chain extender A and chain extender B continue to react, after mixing uniformly, cooling is carried out, neutralizing agent and deionized water are stirred and dispersed, to obtain polyurethane emulsion;Modified pigment, surfactant and 2 / 3 solvent are stirred uniformly, to obtain dispersion;Polyurethane emulsion and the remaining solvent are added to dispersion, and fully stirred and mixed, it is obtained.The UV ink synthesis method involved in the present application is simple, and the preparation condition is mild, and the solvent system friendly to environment can be used, so that large-scale production and application can be realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of UV ink, and relates to a kind of water-based UV ink for ink-jet printing and a preparation method thereof. BACKGROUND

[0002] UV curing ink-jet technology is an advanced printing technology that skillfully combines the convenience of ink-jet printing with the efficiency of photocuring systems. The main advantage of this technology is that it is more environmentally friendly during the printing process. In addition, it also has the characteristics of low energy consumption and rapid curing, which makes it have significant advantages in production efficiency. UV curing ink-jet technology is suitable for a variety of different substrates, whether it is paper, plastic or metal, it can provide excellent printing quality. Its excellent overall performance makes it a very promising technology in the field of industrial printing.

[0003] Water-based UV ink-jet ink is an innovative ink technology that combines the environmental characteristics of water-based ink and the rapid curing advantages of UV ink. This ink can be quickly printed and dried during the printing process, has low viscosity and thin film forming characteristics, almost no odor, providing users with a more comfortable and healthy working environment. However, the dispersion stability of the colorant has a decisive influence on the quality of the ink, although the existing water-based UV ink-jet ink has shown good printing smoothness, but the dispersion of the colorant pigment is poor, which leads to insufficient adhesion after the ink-jet ink is cured; in addition, water-based UV ink-jet ink must have weather resistance in the sun while being stored for a long time.

[0004] Patent document CN116102919A discloses a water-based ink and its printing process, the ink includes 25-35 parts by weight of water-based polyurethane, 8-12 parts by weight of water-based chlorovinyl emulsion, 23-37 parts by weight of fluorine-modified polyacrylate emulsion, 3-5 parts by weight of colorant, 1-2 parts by weight of silane coupling agent and 25 parts by weight of ethanol solution; the ink can improve the printing speed of PVC, and has weather resistance and low temperature resistance. However, in this patent document, the fluorine-modified polyacrylate mainly improves the weather resistance and hydrophobicity, and has limited direct contribution to adhesion. The amount of decoupling agent modified pigment is low, and the silane coupling agent may not be sufficient to fully improve the interfacial bonding force between the resin and the substrate, especially for the fluorine-modified component with high surface energy, the dispersion improvement is limited. SUMMARY

[0005] The present application aims to provide a kind of inkjet printing water-based UV ink and its preparation method, the present application provides a kind of aldehyde group-containing polyurethane compound, as ink binder, its adhesion performance and high temperature resistance performance are excellent, with good application value;The polyurethane compound provided in the present application is mainly obtained by grafting glycerol with propylene aldehyde, the aldehyde group of the main chain of polyurethane compound, so that it can interact with the amino group on the surface of polydopamine-coated pigment, increase the compatibility of pigment, improve the adhesion of ink and its high temperature resistance;The UV ink synthesis method involved in the present application is simple, the preparation condition is mild, and the environment-friendly solvent system can be used, so that large-scale production and application can be realized.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A preparation method of a kind of inkjet printing water-based UV ink includes the following steps:

[0008] S1, preparation of polyurethane emulsion: after dehydration, glycol is placed in a reaction kettle, MDI, HDI and organic tin catalyst are added and stirred to react, chain extender A and chain extender B are added to continue to react, chain extender C is added and uniformly mixed, then cooling is carried out, neutralizing agent and deionized water are added and stirred to disperse, to obtain polyurethane emulsion;

[0009] S2, preparation of dispersion: the modified pigment, surfactant and 2 / 3 solvent are uniformly stirred to obtain a dispersion;

[0010] S3, preparation of ink: polyurethane emulsion and the remaining solvent are added to the dispersion and fully stirred to mix, and the ink is obtained.

[0011] As a preferred technical solution of the present application, in step S1, the mass ratio of glycol, MDI, HDI, organic tin catalyst, chain extender A, chain extender B, chain extender C, neutralizing agent and deionized water is 22-26:2-3:11-14:0.15-0.18:1.2-1.4:1.5-1.8:0.6-0.8:2.0-2.4:70-80.

[0012] As a preferred technical solution of the present application, in step S1, the glycol is PBA, i.e. polybutylene adipate-1,4, Mn=1000;The organic tin catalyst is organic tin catalyst T-12;The chain extender A is 2,2-dimethylol butyric acid;The chain extender C is one or more of 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol;The neutralizing agent is triethylamine.

[0013] As a preferred technical scheme of the present application, in step S1, the stirring reaction is stirring at 65-80℃ for 1.5-2.0h; the time for the continued reaction is 1.0-1.5h; the cooling is cooling to room temperature; and the stirring and dispersing is stirring at 500-800r / min for 50-60min.

[0014] As a preferred technical scheme of the present application, in steps S2-S3, the stirring and uniforming is stirring at 500-800r / min for 40-50min; and the stirring and mixing is stirring at 800-1000r / min for 20-30min.

[0015] As a preferred technical scheme of the present application, in steps S2-S3, the mass ratio of the polyurethane emulsion, the modified pigment, the surfactant and the solvent is 30-35:20-23:2-3:50-62; the surfactant is an anionic surfactant, sodium dodecyl sulfonate; and the solvent is composed of an organic solvent and deionized water, specifically, the solvent is composed of isopropyl alcohol and deionized water at a mass ratio of 1:4.

[0016] As a preferred technical scheme of the present application, the preparation method of the chain extender B comprises: mixing propylene aldehyde, thioglycerol and n-hexane in a reaction kettle, adding a photoinitiator, treating under UV light irradiation, placing in a rotary evaporator to remove the solvent, and then washing with water and reducing pressure distillation.

[0017] As a preferred technical scheme of the present application, the UV light irradiation is 365nm ultraviolet irradiation for 3-4h; the mass ratio of the propylene aldehyde, the thioglycerol, the n-hexane and the photoinitiator is 10-13:22-28:20-30:0.7-0.8; and the photoinitiator is photoinitiator 1173.

[0018] As a preferred technical scheme of the present application, the preparation method of the modified pigment comprises the following steps:

[0019] Dopamine hydrochloride and 2 / 3 Tris-HCl buffer solution are mixed to obtain a dopamine hydrochloride solution, pigments and the remaining Tris-HCl buffer solution are mixed and ultrasonically treated, the dopamine hydrochloride solution is added and ultrasonically mixed and stirred, centrifuged, washed, and vacuum dried.

[0020] As a preferred technical scheme of the present application, the mass ratio of the dopamine hydrochloride, the Tris-HCl buffer and the pigment is 1.0-1.3:300-320:10-12; the ultrasonic mixing is 150-180W ultrasonic mixing for 10-15min; the stirring treatment is stirring at 180-200r / min for 10-12h; the centrifugation is centrifugation at 8000-10000r / min for 10min; the washing is washing 3 times with deionized water; the vacuum drying is vacuum drying at 60℃ until constant weight; and the concentration of the Tris-HCl buffer is 1M, and pH=8.5.

[0021] Advantages of the present application:

[0022] 1. The present application provides an aldehyde group-containing polyurethane compound, which has excellent adhesion and high temperature resistance as an ink binder, and has good application value.

[0023] 2. The polyurethane compound provided by the present application is mainly modified by grafting propylene aldehyde on thio-glycerol, and the aldehyde groups in the main chain of the polyurethane compound can interact with the amino groups on the surface of the polydopamine-coated pigment, thereby increasing the compatibility of the pigment, improving the adhesion of the ink, and improving the high temperature resistance of the ink.

[0024] 3. The UV ink synthesis method according to the present application is simple, has mild preparation conditions, and can use environmentally friendly solvent systems, so that large-scale production and application can be easily realized. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with the examples.

[0026] Example 1

[0027] A preparation method of the inkjet printing water-based UV ink includes the following steps.

[0028] S1, preparation of the polyurethane emulsion: after the dihydric alcohol is vacuumed at 110 DEG C, 0.09 MPa for 1 h, it is placed in a reaction kettle, MDI, HDI and organic tin catalyst are added, stirred at 65 DEG C for 1.5 h, chain extender A and chain extender B are added and reacted for 1.0 h, after mixing the chain extender C, it is cooled to room temperature, a neutralizing agent and deionized water are added and stirred at 500 r / min for 50 min, to obtain the polyurethane emulsion; wherein, the mass ratio of the dihydric alcohol, MDI, HDI, organic tin catalyst, chain extender A, chain extender B, chain extender C, neutralizing agent and deionized water is 22:2:11:0.15:1.2:1.5:0.6:2.0:70; the dihydric alcohol is poly-1, 4-butanediol adipate, Mn = 1000; the organic tin catalyst is organic tin catalyst T-12; the chain extender A is 2, 2-dimethylol butyric acid; the chain extender C is 1, 3-propanediol; the neutralizing agent is triethylamine;

[0029] S2, preparation of the dispersion: the modified pigment, surfactant and 2 / 3 solvent are stirred at 500 r / min for 40 min, to obtain the dispersion;

[0030] S3, preparation of the ink: the polyurethane emulsion and the remaining solvent are added to the dispersion and stirred at 800 r / min for 20 min, to obtain the ink.

[0031] The mass ratio of the polyurethane emulsion, modified pigment, surfactant and solvent is 30:20:2:50; the surfactant is sodium dodecyl sulfonate; the solvent is composed of isopropyl alcohol and deionized water with a mass ratio of 1:4;

[0032] The preparation method of the chain extender B comprises the following steps: the propyl aldehyde, thio-glycerol and n-hexane are mixed uniformly in a reaction kettle, a photoinitiator is added and irradiated by 365 nm ultraviolet light for 3 h, it is placed in a rotary evaporator to remove the solvent, and then washed with water and distilled under reduced pressure, to obtain the chain extender B; wherein, the UV light irradiation is 365 nm; the mass ratio of the propyl aldehyde, thio-glycerol, n-hexane and photoinitiator is 10:22:20:0.7; the photoinitiator is photoinitiator 1173.

[0033] The preparation method of the modified pigment comprises the following steps:

[0034] Dopamine hydrochloride and 2 / 3 Tris-HCl buffer solution are mixed to obtain a dopamine hydrochloride solution, pigments and the remaining Tris-HCl buffer solution are mixed for 10 minutes under ultrasonic waves of 150 W, the dopamine hydrochloride solution is added and mixed for 5 minutes under ultrasonic waves of 150 W, then stirring is performed at 180 r / min for 10 hours, centrifugation is performed at 8000 r / min for 10 minutes, washing is performed with deionized water for 3 times, and vacuum drying is performed at 60 DEG C until a constant weight is obtained, thereby obtaining the product; wherein the mass ratio of the dopamine hydrochloride, the Tris-HCl buffer solution and the pigments is 1.0:300:10; and the pigments are carbon black.

[0035] Example 2

[0036] A preparation method of an inkjet printing water-based UV ink comprises the following steps.

[0037] S1, preparation of the polyurethane emulsion: after dihydric alcohol is vacuumed at 110 DEG C and 0.09 MPa for 1 hour to remove water, the dihydric alcohol is placed in a reaction kettle, MDI, HDI and organic tin catalyst are added and stirred at 72 DEG C for 1.8 hours, chain extender A and chain extender B are added and reacted for 1.2 hours, chain extender C is added and uniformly mixed, then the temperature is lowered to room temperature, a neutralizing agent and deionized water are added and stirred at 650 r / min for 55 minutes, thereby obtaining the polyurethane emulsion; wherein the mass ratio of the dihydric alcohol, the MDI, the HDI, the organic tin catalyst, the chain extender A, the chain extender B, the chain extender C, the neutralizing agent and the deionized water is 24:2.5:12:0.16:1.3:1.6:0.7:2.2:75; the dihydric alcohol is poly-1, 4-butanediol adipate with Mn=1000; the organic tin catalyst is organic tin catalyst T-12; the chain extender A is 2, 2-dimethylol butyric acid; the chain extender C is 1, 3-propanediol; and the neutralizing agent is triethylamine;

[0038] S2, preparation of the dispersion: the modified pigments, a surfactant and 2 / 3 solvents are stirred at 650 r / min for 45 minutes, thereby obtaining the dispersion;

[0039] S3, preparation of the ink: the polyurethane emulsion and the remaining solvents are added to the dispersion and stirred at 900 r / min for 25 minutes, thereby obtaining the ink.

[0040] The mass ratio of the polyurethane emulsion, the modified pigments, the surfactant and the solvents is 32:22:2.5:56; the surfactant is sodium dodecyl sulfonate; and the solvents are composed of isopropyl alcohol and deionized water at a mass ratio of 1:4;

[0041] The preparation method of the chain extender B comprises the following steps: uniformly mixing propenal, thioglycerol and n-hexane in a reaction kettle, adding a photoinitiator, irradiating under 365nm ultraviolet light for 3.5h, placing in a rotary evaporator to remove the solvent, and then washing with water and performing reduced pressure distillation to obtain the chain extender B; wherein the UV light irradiation is UV light irradiation; the mass ratio of the propenal, the thioglycerol, the n-hexane and the photoinitiator is 12:25:25:0.75; and the photoinitiator is a photoinitiator 1173.

[0042] The preparation method of the modified pigment comprises the following steps:

[0043] Dopamine hydrochloride and 2 / 3 Tris-HCl buffer solution are mixed to obtain a dopamine hydrochloride solution, pigments and the remaining Tris-HCl buffer solution are mixed under ultrasonic waves of 165W for 12min, the dopamine hydrochloride solution is added and mixed under ultrasonic waves of 165W for 8min, then stirring is performed at 190r / min for 11h, centrifugation is performed at 9000r / min for 10min, washing is performed with deionized water for 3 times, and vacuum drying is performed at 60℃ until the weight is constant to obtain the modified pigment; wherein the mass ratio of the dopamine hydrochloride, the Tris-HCl buffer solution and the pigments is 1.2:310:11; and the pigments are carbon black.

[0044] Example 3

[0045] The preparation method of the inkjet printing water-based UV ink comprises the following steps.

[0046] S1, preparation of the polyurethane emulsion: after vacuumizing and removing water at 110℃ and 0.09MPa for 1h, glycol is placed in a reaction kettle, MDI, HDI and organotin catalyst are added and stirred at 80℃ for 2.0h, chain extender A and chain extender B are added and continue to react for 1.5h, chain extender C is added and uniformly mixed, then the temperature is lowered to room temperature, a neutralizing agent and deionized water are added and stirred at 800r / min for 60min to obtain the polyurethane emulsion; wherein the mass ratio of the glycol, the MDI, the HDI, the organotin catalyst, the chain extender A, the chain extender B, the chain extender C, the neutralizing agent and the deionized water is 26:3:14:0.18:1.4:1.8:0.8:2.4:80; the glycol is poly-1,4-butanediol adipate with Mn=1000; the organotin catalyst is organotin catalyst T-12; the chain extender A is 2,2-dimethylol butyric acid; the chain extender C is 1,3-propanediol; and the neutralizing agent is triethylamine.

[0047] S2, preparation of the dispersion liquid: the modified pigment, a surfactant and 2 / 3 solvent are stirred at 800r / min for 50min to obtain the dispersion liquid;

[0048] S3, preparation of the ink: the polyurethane emulsion and the remaining solvent are added to the dispersion liquid and stirred at 1000r / min for 30min to obtain the ink.

[0049] The mass ratio of the polyurethane emulsion, modified pigment, surfactant and solvent is 35:23:3:62; the surfactant is sodium dodecyl sulfonate; the solvent is composed of isopropyl alcohol and deionized water in a mass ratio of 1:4;

[0050] The preparation method of the chain extender B comprises the following steps: uniformly mixing propylene aldehyde, thioglycerol and n-hexane in a reaction kettle, adding a photoinitiator, irradiating under 365nm ultraviolet light for 4h, placing in a rotary evaporator to remove the solvent, and then washing with water and reducing pressure distillation; wherein the UV light irradiation is UV light irradiation; the mass ratio of the propylene aldehyde, thioglycerol, n-hexane and photoinitiator is 13:28:30:0.8; and the photoinitiator is photoinitiator 1173.

[0051] The preparation method of the modified pigment comprises the following steps:

[0052] Dopamine hydrochloride and 2 / 3 Tris-HCl buffer solution are mixed to obtain a dopamine hydrochloride solution, pigments and the remaining Tris-HCl buffer solution are mixed under ultrasonic waves at 180W for 15min, the dopamine hydrochloride solution is added and mixed under ultrasonic waves at 180W for 10min, then stirred at 200r / min for 12h, centrifuged at 10000r / min for 10min, washed with deionized water for 3 times, and dried at 60℃ under vacuum until the weight is constant; wherein the mass ratio of the dopamine hydrochloride, Tris-HCl buffer solution and pigments is 1.3:320:12; and the pigments are carbon black.

[0053] Comparative Example 1

[0054] Comparative Example 1 is different from Example 3 in that propylene aldehyde is used instead of chain extender B, and the other components, preparation steps and parameters are consistent.

[0055] Comparative Example 2

[0056] Comparative Example 2 is different from Example 3 in that thioglycerol is used instead of chain extender B, and the other components, preparation steps and parameters are consistent.

[0057] Comparative Example 3

[0058] Comparative Example 3 is different from Example 3 in that chain extender C is used instead of chain extender B, and the other components, preparation steps and parameters are consistent.

[0059] Comparative Example 4

[0060] Comparative Example 4 is different from Example 3 in that the pigments are not modified, and the other components, preparation steps and parameters are consistent.

[0061] The ink prepared in Examples 1-3 and Comparative Examples 1-4 was subjected to the following performance tests, and the test results are shown in Table 1.

[0062] Adhesion test: According to GB / T 9286-88, 1mm grid method was used.

[0063] Temperature resistance test: According to GB / T1735;

[0064] Table 1

[0065] adhesion (%) temperature resistance (°C) print pattern Example 1 98 265 clear pattern, normal color Example 2 97 263 clear pattern, normal color Example 3 95 258 clear pattern, normal color Comparative Example 1 82 213 relatively clear pattern, normal color Comparative Example 2 85 186 relatively clear pattern, normal color Comparative Example 3 76 182 partly unclear pattern, normal color Comparative Example 4 71 168 partly unclear pattern, partly light color

[0066] As can be seen from the test results in Table 1, compared with Comparative Examples 1-4, the UV ink prepared in Examples 1-3 has excellent adhesion and high temperature resistance, and the printing is smooth, and the color development effect is good.

[0067] The present application introduces multiple active hydroxyl groups by click reaction of propylene aldehyde and thioglycerol, which can react with isocyanate, so that the main chain of the polyurethane compound is introduced with aldehyde group, and the pigment is coated with dopamine, so that the surface of the pigment is rich in amino groups, which can interact with the aldehyde groups in the polyurethane emulsion, increase the dispersibility of the pigment, and improve the binding force between the pigment and the polyurethane compound, so that the UV ink has high hardness, high adhesion and high temperature resistance. The UV ink prepared by the present application has wide applicability and can be applied to various scenes such as textiles, wood and metal.

[0068] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the present application, and any indirect modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are within the scope of the present application.

Claims

1. A method for the preparation of an aqueous UV ink for inkjet printing, characterized in that, The preparation method comprises the following steps: S1, preparation of polyurethane emulsion: after dehydration, the dihydric alcohol is placed in a reaction kettle, MDI, HDI and organic tin catalyst are added and stirred to react, chain extender A and chain extender B are added to continue to react, chain extender C is added and uniformly mixed, then cooling is carried out, a neutralizing agent and deionized water are added and stirred to disperse, and the polyurethane emulsion is obtained; the dihydric alcohol is PBA; the chain extender A is 2,2-dimethylol butyric acid; the chain extender C is one or more of 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol; and the neutralizing agent is triethylamine; S2, preparation of dispersion liquid: the modified pigment, the surfactant and 2 / 3 solvent are uniformly stirred to obtain a dispersion liquid; S3, preparation of ink: the polyurethane emulsion and the remaining solvent are added to the dispersion liquid and fully stirred to mix, and the ink is obtained; The preparation method of the chain extender B comprises the following steps: propylene aldehyde, thio-glycerol and n-hexane are uniformly mixed in a reaction kettle, a photoinitiator is added, after UV light irradiation treatment, the mixture is placed in a rotary evaporator to remove the solvent, and then water washing and reduced pressure distillation are carried out, and the chain extender B is obtained. The preparation method of the modified pigment comprises the following steps: Dopamine hydrochloride and 2 / 3 Tris-HCl buffer solution are mixed to obtain a dopamine hydrochloride solution, the pigment and the remaining Tris-HCl buffer solution are mixed and ultrasonically treated, the dopamine hydrochloride solution is added and ultrasonically mixed and stirred, centrifuged, washed and vacuum dried, and the modified pigment is obtained.

2. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: In step S1, the mass ratio of the dihydric alcohol, MDI, HDI, organic tin catalyst, chain extender A, chain extender B, chain extender C, neutralizing agent and deionized water is 22-26:2-3:11-14:0.15-0.18:1.2-1.4:1.5-1.8:0.6-0.8:2.0-2.4:70-80.

3. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: In step S1, the stirring reaction is stirring at 65-80℃ for 1.5-2.0h; the time of the continuous reaction is 1.0-1.5h; and the stirring and dispersing is stirring at 500-800r / min for 50-60min.

4. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: In steps S2-S3, the uniform stirring is stirring at 500-800r / min for 40-50min; and the stirring and mixing is stirring at 800-1000r / min for 20-30min.

5. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: The mass ratio of the polyurethane emulsion, modified pigment, surfactant and solvent is 30-35:20-23:2-3:50-62; the surfactant is an anionic surfactant; and the solvent is composed of an organic solvent and deionized water.

6. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: In the preparation of the chain extender B, the UV light irradiation is 365nm ultraviolet irradiation for 3-4h; and the mass ratio of the propylene aldehyde, thio-glycerol, n-hexane and photoinitiator is 10-13:22-28:20-30:0.7-0.

8.

7. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: The mass ratio of the dopamine hydrochloride, Tris-HCl buffer solution and pigment is 1.0-1.3:300-320:10-12.

8. The method for preparing an inkjet printing water-based UV ink according to claim 1, characterized in that: The ultrasonic mixing is 150-180W ultrasonic for 10-15min; the stirring treatment is stirring at 180-200r / min for 10-12h.

9. An inkjet printing water-based UV ink prepared by the preparation method according to any one of claims 1-8.