Environmentally friendly modified ink diluent and preparation method thereof

Abstract

The present invention relates to the field of printing, and specifically provides an environmentally friendly modified ink diluent and a preparation method thereof. The environmentally friendly modified ink diluent comprises the following raw materials by weight: 1-3 parts of a highly compatible dispersant, 2-4 parts of a modified emulsifier, and 55-65 parts of deionized water. The environmentally friendly modified ink diluent has the characteristics of low toxicity, low VOC emission, non-flammable and non-explosive, etc., is more friendly to the environment and the health of employees, and also enhances compatibility with printing equipment and improves the quality of printed products.

Description

Technical Field

[0001] The invention belongs to the field of printing, and in particular relates to an environmentally friendly modified ink diluent and a preparation method thereof. Background Art

[0002] Ink diluent is an auxiliary material used to adjust the viscosity and fluidity of ink. With the increasingly stringent environmental regulations, benzene-containing solvent-based inks have been banned. Currently, most printing companies use low-toxic mixed organic solvent-based diluents. For example, patent CN112680018B provides a diluent for printing Miniled backlight solder mask ink, in which butanone, white spirit and ethyl acetate as volatile liquids can accelerate the evaporation rate of ink. By combining isopropyl alcohol, ethylene glycol monobutyl ether and naphthalene, the toughness of the ink and the applicability can be effectively improved. Compared with traditional diluents, although this type of diluent reduces toxicity to a certain extent, it still has some limitations: first, the volatilization of low-toxic organic solvents during the drying process of ink will still affect the environment and the health of employees; second, organic solvents are flammable and explosive, with high potential risks.

[0003] Environmentally friendly ink diluents need to have the characteristics of low toxicity, low VOC emissions, good biodegradability, etc. Currently, only water-based ink diluents can truly meet the requirements of green environmental protection. Water-based environmentally friendly ink diluents are usually made of water and some additives. For example, patent CN117247695B discloses a diluent for water-based thermal transfer ink and a preparation method thereof, which includes a thickener, deionized water, a diluent, a dispersant and a defoaming agent. The diluent solves the problem of poor printing quality of ink diluents prepared with sodium alginate or starch as a thickener, but may still need to overcome challenges in terms of compatibility.

[0004] For this reason, there is an urgent need for an environmentally friendly ink diluent with high compatibility on the market. Summary of the invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides an environmentally friendly modified ink diluent and a preparation method thereof, which improves the quality of inkjet printing by changing the thixotropy of the ink while meeting the requirements of green printing, thereby solving the compatibility problem of the printing method.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] On one hand, the present invention provides an environmentally friendly modified ink diluent, which comprises the following raw materials in parts by weight: 1-3 parts of a highly compatible dispersant, 2-4 parts of a modified emulsifier and 55-65 parts of deionized water.

[0008] The ink diluent provided by the present invention is an aqueous diluent, which is mainly used to reduce the viscosity of the ink. It contains a small amount of organic solvent, which greatly reduces the emission of VOCs, improves the printing operation environment, and is beneficial to the health of employees; at the same time, it also reduces the fire hazards caused by static electricity and flammable solvents, and reduces the solvent odor remaining on the surface of the printed matter.

[0009] In some embodiments, the preparation steps of the highly compatible dispersant are as follows:

[0010] S1, stirring 2-mercaptoethanol and tripotassium phosphate-acetone solution for 5-20 min, then adding carbon disulfide and stirring for 5-20 min, then adding benzyl bromide and continuing stirring for 5-20 min, filtering after the stirring, washing, rotary evaporation, and purification to obtain reactant 1;

[0011] S2, stirring ε-caprolactone, the reactant 1 obtained in step S1, 1,8-diazabicyclo[5.4.0]undec-7-ene and tetrahydrofuran at 50-70° C. for 20-30 h, precipitating in methanol, and drying under vacuum at 30-50° C. to constant weight to obtain an amphiphilic block reactant 2;

[0012] S3, heating pentaerythritol, dimethylolpropionic acid and p-toluenesulfonic acid to 140-150° C. under inert gas protection, stirring for 2-4 hours, then cooling to 60-80° C., adding acetone and stirring until dissolved, precipitating in petroleum ether, filtering, and vacuum drying at room temperature to constant weight to obtain reactant 3;

[0013] S4, under the protection of inert gas, the reactant 3 obtained in step S3 and acrylic acid are stirred and dissolved at 100-120° C., then p-toluenesulfonic acid is added and stirred for 4-6 hours, and when the temperature is lowered to 50-70° C., anhydrous ethanol is added to dissolve, and the mixture is precipitated in deionized water to obtain a branched structure reactant 4;

[0014] S5. The reactant 2 obtained in step S2, the reactant 4 obtained in step S4 and azobisisobutyronitrile are stirred and dissolved in N,N-dimethylformamide, and then stirred at 70-90° C. for 10-14 hours. After stirring, the mixture is precipitated in ether, filtered, and vacuum dried at 50-70° C. to constant weight to obtain the highly compatible dispersant.

[0015] Since most inks are not miscible with water, in the actual printing process, whether it is inkjet printing or screen printing, if the printed product is to achieve good color and clarity quality, the ink must be evenly dispersed in the diluent to form a uniform ink slurry.

[0016] The highly compatible dispersant provided in the present application contains an amphiphilic block structure. On the one hand, its hydrophobic segment interacts with the dye particles to adsorb and encapsulate the dye; on the other hand, its hydrophilic segment has an electrostatic repulsion effect, which can stabilize the hydrophobic dye and the polymer inclusion complex, making the dispersion of the dye particles stable. However, the applicant found that the diluted ink was not completely compatible with inkjet printing, resulting in quality problems such as inconsistent colors during the printing process.

[0017] The ink used in inkjet printing is different from the traditional screen printing process in terms of viscosity and thixotropy: in order for the ink to be ejected smoothly from the nozzle, it is necessary to form sufficiently small droplets that will not block the nozzle, which requires low viscosity; and in order for the ejected ink droplets to adhere to the printing substrate and not spread around, causing the characters to become blurred, this requires good thixotropic properties. However, thixotropic properties and viscosity are two contradictory properties. For this reason, the applicant introduced a hyperbranched structure into the dispersant to improve the thixotropic properties of the ink; and through a carefully designed block structure, the dispersant tends to associate within the molecule and does not cause additional thickening. The combination of the two successfully improved the quality problems of inkjet printing and thus solved the compatibility problem of the printing method.

[0018] In some embodiments, the mass ratio of 2-mercaptoethanol, carbon disulfide and benzyl bromide in step S1 is 1:(2.84-3.02):(2.11-2.27).

[0019] In some embodiments, the mass ratio of ε-caprolactone to reactant 1 in step S2 is (1.95-2.08):1.

[0020] In some embodiments, the mass ratio of pentaerythritol to dimethylolpropionic acid in step S3 is 1:(3.87-4.01).

[0021] In some embodiments, the mass ratio of reactant 3 to acrylic acid in step S4 is 1:(0.38-0.39).

[0022] In some embodiments, the mass ratio of reactant 2 to reactant 4 in step S5 is (0.42-0.55):1.

[0023] The applicant avoids competitive adsorption inside the dispersant by specifically selecting the types and proportions of raw materials, thereby achieving the best dispersing effect.

[0024] In some embodiments, the preparation steps of the modified emulsifier are as follows: dissolve polyethylene polyamine in N,N-dimethylformamide, add valeric acid-N,N-dimethylformamide solution, stir at 80-100°C for 3-5h, and obtain the modified emulsifier by reduced pressure distillation.

[0025] In some embodiments, the mass ratio of the polyethylene polyamine to n-valeric acid is 1:(0.18-0.20).

[0026] On the basis of the above-mentioned dispersant, the applicant also found that although the printing quality has achieved uniform and clear color, the color of the printed product after increasing the dye concentration on certain substrates is not full and bright enough. For this reason, the present application enhances the color saturation of the printed product by modifying the emulsifier. On the one hand, by reducing the tension with the substrate surface, the adhesion and leveling of the ink are enhanced; on the other hand, the problem of the thixotropy of the ink slurry being affected due to the insufficient bonding between the long chain of the emulsifier and the molecular layer of the dispersant is avoided.

[0027] Another aspect of the present invention provides a method for preparing an environmentally friendly modified ink diluent, comprising the following steps: uniformly stirring a highly compatible dispersant, a modified emulsifier and deionized water to obtain the environmentally friendly modified ink diluent.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The environmentally friendly ink diluent provided by the present invention has the characteristics of low toxicity, low VOC emission, non-flammable and non-explosive, etc., which is more friendly to the environment and employee health. At the same time, it also enhances the compatibility with printing equipment and improves the quality of printed products.

[0030] 2. The highly compatible dispersant in the environmentally friendly ink diluent provided by the present invention can stabilize the dispersion of dye particles, and the highly compatible dispersant can adjust the thixotropic properties and viscosity, thereby improving the quality problem of inconsistent color of printed products caused by incomplete compatibility between ink and inkjet printing.

[0031] 3. The present invention reduces the tension between the ink and the surface substrate by modifying the emulsifier, enhances the adhesion and leveling of the ink, and solves the problem that the color of the printed product is not full and bright enough; and avoids the problem that the thixotropy of the slurry is affected by the insufficient bonding between the long chain of the emulsifier and the molecular layer of the dispersant through the specific selection of the types and proportions of the raw materials. DETAILED DESCRIPTION

[0032] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0033] In order to facilitate those skilled in the art to implement the present invention, some raw materials and manufacturers of the examples are described as follows: Polyethylene polyamine was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., Mw=275.

[0034] It should be noted that the post-treatment steps such as “rotary evaporation”, “recrystallization” and “distillation under reduced pressure” appearing in the following embodiments are selected by those skilled in the art according to actual operations.

[0035] Preparation Example 1

[0036] The preparation steps of highly compatible dispersant-A are as follows:

[0037] S1, 20 g of 2-mercaptoethanol and 54 g of tripotassium phosphate-400 mL of acetone solution were stirred for 15 min, then 58.5 g of carbon disulfide was added and stirred for 15 min, then 44 g of benzyl bromide was added and stirred for 15 min, after stirring, the mixture was filtered, washed with acetone for 3 times, rotary evaporated, and recrystallized to obtain reactant 1;

[0038] S2, 24 g of ε-caprolactone, 12 g of the reactant 1 obtained in step S1, 0.5 g of 1,8-diazabicyclo[5.4.0]undec-7-ene and 100 mL of tetrahydrofuran were stirred at 60° C. for 24 h, precipitated in methanol, and dried in vacuo at 40° C. to constant weight to obtain an amphiphilic block reactant 2;

[0039] S3, 13.8 g of pentaerythritol, 54 g of dimethylol propionic acid and 0.34 g of p-toluenesulfonic acid were heated to 145° C. under nitrogen protection, stirred for 3 h, then cooled to 70° C., acetone was added to dissolve, precipitated in petroleum ether, filtered, and dried in vacuum at room temperature to constant weight to obtain reactant 3;

[0040] S4. Under nitrogen protection, 40 g of the reactant 3 obtained in step S3 and 15.5 g of acrylic acid were stirred and dissolved at 110° C., and then 0.28 g of p-toluenesulfonic acid was added and stirred for 5 h. When the temperature was lowered to 60° C., anhydrous ethanol was added until dissolved, and the mixture was precipitated in deionized water to obtain a branched structure reactant 4.

[0041] S5. Dissolve 21.8 g of reactant 2 obtained in step S2, 47.2 g of reactant 4 obtained in step S4 and 0.64 g of azobisisobutyronitrile in 160 mL of N,N-dimethylformamide, and then stir at 80°C for 12 h. After stirring, precipitate in ether, filter, and vacuum dry at 60°C to constant weight to obtain highly compatible dispersant-A.

[0042] Preparation Example 2

[0043] The preparation steps of highly compatible dispersant-B are as follows:

[0044] S1, 20 g of 2-mercaptoethanol and 54 g of tripotassium phosphate-400 mL of acetone solution were stirred for 15 min, then 58.5 g of carbon disulfide was added and stirred for 15 min, then 44 g of benzyl bromide was added and stirred for 15 min, after stirring, the mixture was filtered, washed with acetone for 3 times, rotary evaporated, and recrystallized to obtain reactant 1;

[0045] S2. Stir 24 g of ε-caprolactone, 12 g of the reactant 1 obtained in step S1, 0.5 g of 1,8-diazabicyclo[5.4.0]undec-7-ene and 100 mL of tetrahydrofuran at 60° C. for 24 h, precipitate in methanol, and dry under vacuum at 40° C. to constant weight to obtain a highly compatible dispersant-B.

[0046] Preparation Example 3

[0047] The preparation steps of highly compatible dispersant-C are as follows:

[0048] The difference between this preparation example and preparation example 1 is that the amount of 2-mercaptoethanol used in step S1 is 22 g.

[0049] Preparation Example 4

[0050] The preparation steps of highly compatible dispersant-D are as follows:

[0051] The difference between this preparation example and preparation example 1 is that the amount of 2-mercaptoethanol used in step S1 is 18 g.

[0052] Preparation Example 5

[0053] The preparation steps of highly compatible dispersant-E are as follows:

[0054] The difference between this preparation example and preparation example 1 is that the amount of ε-caprolactone used in step S2 is 22.5 g.

[0055] Preparation Example 6

[0056] The preparation steps of high compatible dispersant-F are as follows:

[0057] The difference between this preparation example and preparation example 1 is that the amount of ε-caprolactone used in step S2 is 25.2 g.

[0058] Preparation Example 7

[0059] The preparation steps of highly compatible dispersant-G are as follows:

[0060] The difference between this preparation example and preparation example 1 is that the amount of reactant 2 used in step S5 is 18.8 g.

[0061] Preparation Example 8

[0062] The preparation steps of highly compatible dispersant-H are as follows:

[0063] The difference between this preparation example and preparation example 1 is that the amount of reactant 2 used in step S5 is 28.3 g.

[0064] Preparation Example 9

[0065] The preparation steps of modified emulsifier-A are as follows:

[0066] Dissolve 50 g of polyethylene polyamine in 300 mL of N,N-dimethylformamide, add 9.5 g of n-valeric acid-50 mL of N,N-dimethylformamide solution, stir at 90°C for 4 h, and distill under reduced pressure to obtain modified emulsifier-A.

[0067] Preparation Example 10

[0068] The preparation steps of modified emulsifier-B are as follows:

[0069] The difference between this preparation example and preparation example 9 is that the amount of n-valeric acid used is 8.6 g.

[0070] Preparation Example 11

[0071] The preparation steps of modified emulsifier-C are as follows:

[0072] The difference between this preparation example and preparation example 9 is that the amount of n-valeric acid used is 11 g.

[0073] Example 1

[0074] An environmentally friendly modified ink diluent, comprising the following raw materials, by weight: 2 parts of highly compatible dispersant-A, 3 parts of modified emulsifier-A and 60 parts of deionized water.

[0075] The preparation method of the environmentally friendly modified ink diluent in this embodiment comprises the following steps: the highly compatible dispersant-A, the modified emulsifier-A and the deionized water are stirred evenly to obtain the environmentally friendly modified ink diluent.

[0076] Example 2

[0077] An environmentally friendly modified ink diluent, comprising the following raw materials, by weight: 1 part of highly compatible dispersant-A, 2 parts of modified emulsifier-A and 55 parts of deionized water.

[0078] The preparation method of the environmentally friendly modified ink diluent in this embodiment comprises the following steps: the highly compatible dispersant-A, the modified emulsifier-A and the deionized water are stirred evenly to obtain the environmentally friendly modified ink diluent.

[0079] Example 3

[0080] An environmentally friendly modified ink diluent, comprising the following raw materials, by weight: 3 parts of highly compatible dispersant-A, 4 parts of modified emulsifier-A and 65 parts of deionized water.

[0081] The preparation method of the environmentally friendly modified ink diluent in this embodiment comprises the following steps: the highly compatible dispersant-A, the modified emulsifier-A and the deionized water are stirred evenly to obtain the environmentally friendly modified ink diluent.

[0082] Example 4

[0083] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-B.

[0084] Example 5

[0085] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-C.

[0086] Example 6

[0087] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-D.

[0088] Example 7

[0089] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-E.

[0090] Example 8

[0091] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-F.

[0092] Example 9

[0093] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-G.

[0094] Example 10

[0095] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the highly compatible dispersant-A is replaced by an equal portion of highly compatible dispersant-H.

[0096] Embodiment 11

[0097] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified emulsifier-A is replaced by an equal portion of modified emulsifier-B.

[0098] Example 12

[0099] This embodiment provides an environmentally friendly modified ink diluent and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified emulsifier-A is replaced by an equal portion of modified emulsifier-C.

[0100] Performance Testing

[0101] Preparation of dispersed ink: The environmentally friendly modified ink diluent provided in each embodiment is mixed with disperse yellow-232 to obtain ink, and the concentration of disperse yellow-232 in the ink is 8wt%.

[0102] 1. Compatibility test:

[0103] The obtained ink was inkjet printed and screen printed on a substrate of the same material, and the gloss was measured using a gloss meter at an incident angle of 60°. The compatibility of the diluent was shown by comparing the gloss.

[0104] 2. Adhesion test:

[0105] The adhesion test was carried out according to the standard GB / T9286-2021, and the results were divided into levels 5, 4, 3, 2, 1, and 0 from low to high.

[0106] The performance test is shown in Table 1;

[0107] Table 1

[0108]

[0109] It can be seen from the data in Table 1 that the inks of Examples 1-3 have strong adhesion; and under different printing methods, the glossiness difference is small, indicating that its compatibility is high. Compared with Example 1, the highly compatible dispersant used in the ink of Example 4 has no branched structure, which is not conducive to the thixotropic properties of the ink, not only resulting in a decrease in compatibility, but also affecting the tension between the ink and the surface of the substrate, thereby affecting the adhesion. Compared with Example 1, the highly compatible dispersant used in Examples 5-8 changes the amount of synthetic raw materials for the amphiphilic block reactants, which is not conducive to the regular formation of the block structure, resulting in its compatibility being affected. Compared with Example 1, the highly compatible dispersant used in Examples 9-10 changes the ratio of the amphiphilic block structure to the branched structure, making the thixotropic properties and viscosity of the ink inconsistent. Compared with Example 1, the modified emulsifier used in Examples 11-12 changes the content of the amino group, which is not conducive to the adhesion and leveling of the ink.

[0110] The embodiments described above do not impose any form of limitation on the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly modified ink diluent, characterized in that: The composition comprises the following raw materials by weight: 1-3 parts of a highly compatible dispersant, 2-4 parts of a modified emulsifier and 55-65 parts of deionized water; The preparation steps of the highly compatible dispersant are as follows: S1, stirring 2-mercaptoethanol and tripotassium phosphate-acetone solution for 5-20 min, then adding carbon disulfide and stirring for 5-20 min, then adding benzyl bromide and continuing stirring for 5-20 min, filtering after the stirring, washing, rotary evaporation, and recrystallization to obtain reactant 1; S2, stirring ε-caprolactone, the reactant 1 obtained in step S1, 1,8-diazabicyclo[5.4.0]undec-7-ene and tetrahydrofuran at 50-70° C. for 20-30 h, precipitating in methanol, and drying under vacuum at 30-50° C. to constant weight to obtain an amphiphilic block reactant 2; S3, heating pentaerythritol, dimethylolpropionic acid and p-toluenesulfonic acid to 140-150° C. under inert gas protection, stirring for 2-4 hours, then cooling to 60-80° C., adding acetone until dissolved, precipitating in petroleum ether, filtering, and vacuum drying at room temperature to constant weight to obtain reactant 3; S4, under the protection of inert gas, the reactant 3 obtained in step S3 and acrylic acid are stirred and dissolved at 100-120° C., then p-toluenesulfonic acid is added and stirred for 4-6 hours, and when the temperature is lowered to 50-70° C., anhydrous ethanol is added until dissolved, and the mixture is precipitated in deionized water to obtain a branched structure reactant 4; S5, stirring and dissolving the reactant 2 obtained in step S2, the reactant 4 obtained in step S4 and azobisisobutyronitrile in N,N-dimethylformamide, and then stirring at 70-90° C. for 10-14 hours. After the stirring is completed, precipitate in ether, filter, and vacuum dry at 50-70° C. to constant weight to obtain the highly compatible dispersant; In the step S1, the mass ratio of 2-mercaptoethanol, carbon disulfide and benzyl bromide is 1:(2.84-3.02):(2.11-2.27).

2. The environmentally friendly modified ink diluent according to claim 1, characterized in that: The mass ratio of ε-caprolactone to reactant 1 in step S2 is (1.95-2.08):

1.

3. The environmentally friendly modified ink diluent according to claim 1, characterized in that: The mass ratio of pentaerythritol to dimethylolpropionic acid in step S3 is 1:(3.87-4.01).

4. The environmentally friendly modified ink diluent according to claim 1, characterized in that: The mass ratio of reactant 3 to acrylic acid in step S4 is 1:(0.38-0.39).

5. The environmentally friendly modified ink diluent according to claim 1, characterized in that: In step S5, the mass ratio of reactant 2 to reactant 4 is (0.42-0.55):

1.

6. The environmentally friendly modified ink diluent according to claim 1, characterized in that: The preparation steps of the modified emulsifier are as follows: dissolving polyethylene polyamine in N,N-dimethylformamide, adding n-valeric acid-N,N-dimethylformamide solution, stirring at 80-100° C. for 3-5 hours, and performing reduced pressure distillation to obtain the modified emulsifier.

7. The environmentally friendly modified ink diluent according to claim 6, characterized in that: The mass ratio of the polyethylene polyamine to n-valeric acid is 1:(0.18-0.20).

8. A method for preparing the environmentally friendly modified ink diluent according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: uniformly stirring a highly compatible dispersant, a modified emulsifier and deionized water to obtain the environmentally friendly modified ink diluent.

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