Jet printing waterproof dye ink for corrugated paper and preparation method thereof

Abstract

The invention provides jet printing waterproof dye ink for corrugated paper and a preparation method of the jet printing waterproof dye ink for the corrugated paper, the jet printing waterproof dye ink for the corrugated paper comprises a coloring agent, an organic solvent and a surfactant, the hydrophobic end of the water-soluble polymer dye and the pigment are attached to the surface of the corrugated paper to form a physical barrier, and the problems that dye ink is poor in waterproof performance and pigment ink is insufficient in brilliance are solved synergistically. The content ratio of the pigment to the water-soluble polymer dye is (3: 1)-(15: 1) in percentage by mass. The water-soluble polymer dye and the pigment ensure the bright color of the ink, and improve the waterproof and sun-proof performance and compatibility of the ink.

Description

Technical Field

[0001] The invention relates to the field of digital inkjet printing, and in particular to a waterproof dye ink for printing corrugated paper and a preparation method thereof. Background Art

[0002] In recent years, with the explosive growth of e-commerce, the corrugated paper packaging market has grown rapidly, and the global corrugated packaging market has grown faster than expected. Digital inkjet printing has the advantages of on-demand customization, no wastewater generation, and flexible customization, and is widely used in the field of corrugated paper printing.

[0003] At present, the digital printing solutions for corrugated paper on the market are mainly based on water-based inkjet ink, which has the advantage of being green and environmentally friendly. Water-based inkjet ink is divided into water-based pigment ink and water-based dye ink.

[0004] Water-based pigment ink has excellent wear resistance, abrasion resistance and waterproof properties when printed on corrugated paper because the colorant is pigment, which is insoluble in water and contains resin as a binder. However, the color saturation of the pigment is relatively low and it is difficult to meet the color requirements of corrugated boxes.

[0005] Water-based dye inks are brightly colored and can basically meet or reach the traditional color saturation, but because dyes are water-soluble molecules, they have the defect of poor waterproof performance and weak light fastness, which cannot meet the needs of outdoor applications. One of the current improvements is that after inkjet printing, a post-process (such as adding varnish, wax emulsion, etc.) is required to waterproof, which leads to complex processes and higher costs; or by adding modified polyurethane and acrylate resins to the ink composition to form a resin film on the ink surface to achieve excellent waterproof performance, but there is a problem of poor ink compatibility.

[0006] Therefore, it is necessary to develop a waterproof dye ink for printing that meets color requirements while ensuring waterproof and sun-resistant properties and compatibility. Summary of the invention

[0007] The first object of the present invention is to provide a waterproof dye ink for printing on corrugated paper, which is used to solve the problem that the existing waterproof dye ink for printing on corrugated paper cannot simultaneously meet the requirements of color, waterproof and sun-resistant performance and compatibility.

[0008] The second object of the present invention is to provide a preparation scheme for inkjet printing waterproof dye ink for corrugated paper, which is used to prepare the above-mentioned inkjet printing waterproof dye ink for corrugated paper.

[0009] To achieve the first purpose of the present invention, the present invention provides a waterproof dye ink for printing on corrugated paper, which includes a colorant, an organic solvent and a surfactant, wherein the colorant includes a water-soluble polymer dye and a pigment, the water-soluble polymer dye has a hydrophobic end, and the content ratio of the pigment to the water-soluble polymer dye is 3:1 to 15:1 by mass percentage.

[0010] As can be seen from the above scheme, water-soluble polymer dyes are a type of colored polymer compounds that combine dyes with polymer skeletons through covalent bonds. This combination method gives polymer dyes dual functions: it has the characteristics of high strength and easy film-forming properties of polymers, and also has the selective absorption and colorfulness of dyes to light. The mutual entanglement and cross-linking of polymer chains enable dye molecules to be closely arranged together to form a continuous and uniform film layer, thereby showing good film-forming properties; secondly, since polymer dyes have a huge molecular weight and belong to the category of polymers, they have a high binding force with fibers. This strong binding force makes it difficult for dye molecules to migrate or fall off when heated or subjected to other external forces, thereby showing excellent migration resistance and color fastness; at the same time, the polymer chain has good thermal stability and can maintain structural stability at high temperatures, thus also giving polymer dyes good heat resistance; the water-soluble polymer dyes in the present invention contain hydrophobic ends, and the penetration and diffusion of water molecules are reduced by introducing hydrophobic groups or using cross-linked structures, thereby enhancing the water resistance of the dye. In order to further enhance the waterproof performance of the ink, pigments are added to the colorant at the same time. The pigment is a fine powder colored substance with excellent water resistance. In addition, its surface will be treated with a surfactant or dispersant. When it is added to a water-soluble polymer dye with a hydrophobic end, it can ensure that the stability of the ink is not affected. When the ink is printed on corrugated paper and dried, the pigment powder is fixed on the surface of the carton to form a physical barrier, which prevents water from penetrating into the dyeing substance, further improving the waterproofness of the ink. On the other hand, the dye is modified to form a waterproof polymer dye, the hue becomes lighter, and the permeability on the carton is relatively strong. Adding a certain proportion of pigments enhances the waterproofness and the color brightness. Since the pigment provides color stability and hiding power, and the dye can produce stronger and more transparent colors, the combination can create a color effect with both hiding power and transparency. In addition, the pigment has strong sun resistance, which helps to enhance the light resistance of the ink. However, the ratio of pigment to water-soluble polymer dye is 3:1 to 15:1. The reason is that the water resistance of ink depends on the content of pigment in the ink, and the brightness of the color depends entirely on the content of water-soluble polymer dye in the ink. If the pigment content is too much, the ink is prone to insoluble matter, and the color on the carton will appear uneven and the touch will be poor. If the pigment content is too little, the water resistance of the ink is not good enough.

[0011] A further embodiment is that the water-soluble polymer dye is a water-soluble polymer dye having polyhydroxyl groups, specifically selected from Yellow R-01, Red R-01, Blue R-01 and The pigment is an organic pigment, specifically selected from at least one of Phthalocyanine Blue 15:3, Pigment Red 122, Pigment Yellow 155 and Pigment Black 7.

[0012] It can be seen from the above scheme that the above-mentioned water-soluble polymer dye mainly forms hydrogen bonds with cellulose molecules on the surface of corrugated paper through the hydroxyl groups in the dye, so that the dye can be better attached to the surface of the corrugated paper and has high color fastness.

[0013] A further embodiment is that the organic solvent comprises a first organic solvent and a second organic solvent, wherein the first organic solvent is at least one of ethylene glycol and glycerol; and the second organic solvent has a solubility parameter in the range of 15 (J / m 3 ) 1 / 2 Up to 20(J / m 3 ) 1 / 2 At least one of an ester solvent and an ether solvent. The ester solvent is selected from at least one of butyl acetate, dipropylene glycol methyl ether acetate and methyl 3-methoxypropionate; the ether solvent is selected from at least one of propylene glycol monomethyl ether and dialkyl ether.

[0014] It can be seen from the above scheme that the first organic solvent has good moisturizing properties, which can prevent the ink from drying out during printing, but cannot effectively dissolve water-soluble polymer dyes and pigments. The second organic solvent includes ether and ester solvents, which have better solubility and can better dissolve colorants. A series of polymer dyes are highly compatible with polyester / polyether, thereby improving the uniformity of dyeing; ether and ester solvents can also promote the chemical reaction between dyes and fibers, improving the dyeing fixation rate and color fastness; in addition, when selecting, the solubility parameters of the solvent should be considered. Solvents with low solubility parameters have relatively weak dissolving ability, and solvents with high solubility parameters may have higher volatility and affect the environment.

[0015] In a further embodiment, the second organic solvent includes an ester solvent and an ether solvent, and the ester solvent content is 1% to 3% and the ether solvent content is 1% to 3% by mass.

[0016] It can be seen from the above scheme that too little organic solvent may cause the polymer dyes and pigments to be unable to disperse evenly, thus affecting the stability of the ink, the density and water resistance of the ink coating. The dye exists in the dye solution as a suspension, and is prone to particle size growth, aggregation, agglomeration and even precipitation during high-temperature dyeing, affecting the uniformity and color fastness of dyeing; too much organic solvent may over-dissolve the dye, resulting in color lightening or high permeability. This is mainly because ester additives have strong solubility and penetration ability. After printing, the ink will enter the fiber from the fiber surface through the expanded fiber capillaries, resulting in a lighter color for the printed carton. Ether and ester solvents have good permeability on cartons and have a greater impact on color. Therefore, under the above ratio, the ink has good water resistance, color fastness, color brightness and uniformity.

[0017] A further solution is that, by mass percentage, the content ratio of the organic solvent to the colorant is 1:1 to 2:1.

[0018] A further solution is that the waterproof dye ink for printing corrugated paper also includes a surfactant, and the surfactant includes a polyether siloxane surfactant and / or a non-ionic surfactant. Specifically, the polyether siloxane surfactant is selected from at least one of WET240, WET250, WET260 and WET270; the non-ionic surfactant is preferably surfynol-465.

[0019] As can be seen from the above scheme, the surfactant is a polyether siloxane surfactant, which has strong acid and alkali resistance and hydrolysis resistance, which is very important for improving the hydrolysis resistance and weather resistance of the ink coating; the polyether-modified siloxane molecules have a smaller size and excellent wettability, and can effectively penetrate into the tiny gaps on the surface of the pigment, forming a uniform wetting film on its surface, which can improve the dispersibility of the pigment in the ink system and the wettability of the ink itself. In addition, polyether siloxane is both hydrophobic and hydrophilic. The hydrophobic group can connect to the colorant to reduce its surface tension, and the hydrophilic group connects to water to enhance the stability of the ink. At the same time, the unique structure and properties of the polyether siloxane surfactant provide super hydrophobic and super hydrophilic properties, which can form a waterproof coating on the ink coating, further enhancing the waterproof effect.

[0020] A further solution is that the ink for printing waterproof dyes for corrugated paper also includes a pH regulator, the pH regulator is triethanolamine, and the pH of the ink for printing waterproof dyes for corrugated paper is 7 to 9.

[0021] It can be seen from the above scheme that the dye is greatly affected by the pH value during the printing process. When the pH is too low, the cellulose fibers in the corrugated paper cannot ionize negative ions to form covalent bonds with the dye, causing the color to become lighter after printing; when the pH is too high, the water solubility of the dye decreases rapidly; the ink in the above pH value range has a good printing effect.

[0022] A further solution is that, measured by mass percentage, the waterproof dye ink for printing corrugated paper includes 20% to 45% of a colorant, 30% to 45% of an organic solvent, 0.1% to 0.5% of a surfactant, 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.3% of a pH regulator and the remainder of water.

[0023] It can be seen from the above scheme that the above-mentioned waterproof dye ink for printing corrugated paper has an excellent dyeing effect, and while having good waterproof properties, it also solves the problem of poor compatibility of water-soluble polymer dyes in ink.

[0024] In order to achieve the second purpose of the present invention, the present invention provides a method for preparing a waterproof dye ink for printing on corrugated paper, which is used to prepare a waterproof dye ink for printing on corrugated paper described in any of the above schemes, and the preparation method comprises the following steps: S1, adding 30% to 45% of an organic solvent, 0.1% to 0.5% of a surfactant, 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.3% of a pH regulator and water into a stirring barrel by mass percentage, stirring for 15min to 45min at a speed of 500rpm to 800rpm until the solution becomes uniform and transparent; S2, adding a pigment into the above solution, maintaining the speed of step S1, and continuing to stir for 30min to 60min to uniformly disperse the resin in the solution; S3, adding a water-soluble polymer dye to the solution prepared in step S2, maintaining the speed of step S1, and continuing to stir for 45min to 60min to obtain a waterproof dye ink for printing on corrugated paper. DETAILED DESCRIPTION

[0025] The invention provides a waterproof dye ink for printing on corrugated paper. The waterproof dye ink for printing on corrugated paper comprises, by mass percentage, 20% to 45% of a colorant, 30% to 45% of an organic solvent, 0.1% to 0.5% of a surfactant, 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.3% of a pH regulator and the remainder of water.

[0026] The colorant includes a water-soluble polymer dye and a pigment, the water-soluble polymer dye has a hydrophobic end, and the content ratio of the pigment to the water-soluble polymer dye is 3:1 to 15:1 by mass percentage. Preferably, the water-soluble polymer dye is a water-soluble polymer dye having polyhydroxyl groups, selected from Yellow R-01, RedR-01, Blue R-01 and At least one of Black R-01.

[0027] The pigment is an organic pigment, selected from at least one of phthalocyanine blue 15:3, pigment red 122, pigment yellow 155 and pigment black 7.

[0028] The organic solvent includes a first organic solvent and a second organic solvent, wherein the first organic solvent is at least one of ethylene glycol and glycerol; the second organic solvent has a solubility parameter in the range of 15 (J / m 3 ) 1 / 2 Up to 20(J / m 3 ) 1 / 2 At least one of an ester solvent and an ether solvent. The ester solvent is selected from at least one of butyl acetate, dipropylene glycol methyl ether acetate and methyl 3-methoxypropionate, and the ether solvent is selected from at least one of propylene glycol monomethyl ether and dialkyl ether. Preferably, the second organic solvent includes an ester solvent and an ether solvent, and the ester solvent content is 1% to 3% by mass, the ether solvent content is 1% to 3%, and the ratio of the organic solvent to the colorant content is 1:1 to 2:1.

[0029] The surfactant is a polyether siloxane surfactant, specifically at least one selected from WET240, WET250, WET260 and WET270 and a nonionic surfactant surfynol-465.

[0030] The antimicrobial agent is selected from Kathon.

[0031] The pH adjuster is triethanolamine, and the pH of the waterproof dye ink for printing on corrugated paper is 7 to 9.

[0032] The present invention provides a method for preparing a waterproof dye ink for printing on corrugated paper, which is used to prepare the above-mentioned waterproof dye ink for printing on corrugated paper. The preparation method comprises the following steps:

[0033] S1. Add 30% to 45% of organic solvent, 0.1% to 0.5% of surfactant, 0.1% to 0.3% of antibacterial agent, 0.1% to 0.3% of pH regulator and water into a stirring bucket by mass percentage, and stir for 15 to 45 minutes at a speed of 500 to 800 rpm until the solution becomes uniform and transparent;

[0034] S2, adding the pigment into the above solution, maintaining the speed of step S1, and continuing stirring for 30min to 60min to evenly disperse the resin in the solution;

[0035] S3, adding a water-soluble polymer dye to the solution prepared in step S2, maintaining the rotation speed of step S1, and continuing stirring for 45 minutes to 60 minutes to obtain a waterproof dye ink for printing on corrugated paper.

[0036] The following is a description with reference to specific embodiments.

[0037] The waterproof dye ink for printing on corrugated paper was prepared according to the mass percentages shown in Tables 1 and 2 below.

[0038] Table 1

[0039]

[0040] Table 2

[0041]

[0042]

[0043] The preparation method is as follows: S1, adding 30% to 45% of an organic solvent, 0.1% to 0.5% of a surfactant, 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.3% of a pH regulator and water into a stirring barrel by mass percentage, stirring for 15 minutes to 45 minutes at a rotation speed of 500 rpm to 800 rpm until the solution becomes uniform and transparent; S2, adding a pigment into the above solution, maintaining the rotation speed of step S1, continuing to stir for 30 minutes to 60 minutes, and uniformly dispersing the resin in the solution; S3, adding a water-soluble polymer dye to the solution prepared in step S2, maintaining the rotation speed of step S1, and continuing to stir for 45 minutes to 60 minutes to obtain a waterproof dye ink for printing corrugated paper.

[0044] It should be noted that the above examples and comparative examples are prepared using the same process parameters.

[0045] The above embodiments and comparative examples were subjected to performance tests.

[0046] 1. Stability test

[0047] (1) Aging test: The ink is placed in a 60°C environment for one week and two weeks of aging experiments to test its viscosity and surface tension. The ink is considered qualified if the viscosity and surface tension change rate is ≤10%.

[0048] (2) Freezing test: The ink is placed in a -18°C environment for a three-day freezing experiment to test its viscosity and surface tension. The ink is considered qualified if the viscosity and surface tension change rate is ≤10%.

[0049] (3) Insoluble matter test: Take 100g of ink and perform an aging and freezing test (the ink is placed in a -18°C environment) for three days. The aged ink is placed at room temperature and filtered through a negative pressure 0.45PP membrane. Visually inspect the filter screen for insoluble matter. No insoluble matter or trace amounts of insoluble matter are considered qualified.

[0050] 2. Fluency test

[0051] The ink uses EPSON I3200 nozzle as the test nozzle. After continuous printing for 100m, the mesh state is tested. If the broken holes are ≤3 holes, the fluidity is considered qualified.

[0052] 3. Waterproof performance test

[0053] Soak the printed color blocks in water for 2 hours, test the color density before and after soaking, and it is considered qualified if the attenuation rate is ≤10%.

[0054] The specific test results are shown in Tables 3 and 4 below.

[0055] Table 3

[0056]

[0057]

[0058] Table 4

[0059]

[0060]

[0061] It can be seen from the above test results that, compared with Example 1, no organic pigment is added to Comparative Example 1, and it can be seen that the performance in terms of printing fluency and waterproof performance is not as good as that in Example 1; Comparative Example 2 reduces the amount of organic pigment relative to Example 1, and the mass ratio of pigment to water-soluble polymer dye is less than 3:1-15:1, and it can be seen that the waterproof performance is not as good as that in Example 1; Comparative Example 3 does not add dye relative to Example 4, insoluble matter exists in the ink, and the printing fluency performance is not as good as that in Example 1; Comparative Example 4 reduces the amount of water-soluble polymer dye relative to Example 4, and the mass ratio of pigment to water-soluble polymer dye is greater than 3:1-15:1, insoluble matter exists in the ink, and the printing fluency performance and waterproof performance are not as good as those in Example 4; Comparative Example 5 For Example 2, the amount of organic solvent is reduced, the mass ratio of organic solvent: colorant is less than 1:1-2:1, insoluble matter exists in the ink, and the printing smoothness performance and waterproof performance are not as good as Example 2; Comparative Example 6 increases the amount of organic solvent relative to Example 3, the mass ratio of organic solvent: colorant is greater than 1:1-2:1, and the printing smoothness performance and waterproof performance of the ink are not as good as Example 3; Comparative Example 7 is set relative to Example 2 to reduce the amount of ester solvent added, the ester content is less than 1%-3%, insoluble matter exists in the ink, and the printing smoothness performance and waterproof performance are not as good as Example 2; Comparative Example 8 increases the amount of ester solvent relative to Example 3, the ester content is greater than 1%-3%, and the waterproof performance is not as good as Example 3.

[0062] In summary, the present invention provides a waterproof dye ink for printing corrugated paper, which has waterproof properties. The present invention first utilizes a water-soluble polymer dye, bonds the dye to polyurethane, forms a polyurethane molecular chain, and the hydrophobic group of the polyurethane molecular chain constructs the first waterproof barrier. Further, by adding organic pigment molecules to the colorant, the organic pigment particles themselves have excellent waterproof properties, and also form a physical barrier on the surface of the corrugated paper at the same time, so the waterproof effect of the ink is further enhanced. Secondly, when the water-soluble polymer dye and the organic pigment with a hydrophobic end are added to a solution with water as the main solvent, the ink will be incompatible, affecting the printing fluency. Therefore, two organic solvents are added in this paper, and organic solvents (polyesters, polyethers) with larger solubility coefficient values ​​are used to effectively dissolve water-soluble polymer dyes and pigments. Finally, in order to achieve a brightly colored result, the ratio of water-soluble polymer dyes and pigments is optimized. The main reason is that the color of the dye will become lighter after modification and the permeability of the dye on the surface of the corrugated paper is relatively strong, so the color effect will be enhanced by adding a certain proportion of organic pigments. At the same time, the ratio of organic solvents and colorants is adjusted to avoid color migration and deepen the color effect. Furthermore, ether and ester solvents can promote the reaction between dyes and paper fibers, increase the dyeing rate of ink, and further enhance the dyeing effect.

[0063] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A waterproof dye ink for printing on corrugated paper, characterized in that: The waterproof dye ink for printing corrugated paper comprises a colorant, an organic solvent and a surfactant, wherein the colorant comprises a water-soluble polymer dye and a pigment, the water-soluble polymer dye has a hydrophobic end, and the content ratio of the pigment to the water-soluble polymer dye is 3:1 to 15:1 in terms of mass percentage.

2. The waterproof dye ink for printing corrugated paper according to claim 1, characterized in that: The water-soluble polymer dye is a water-soluble polymer dye having polyhydroxyl groups; The pigment is an organic pigment.

3. The waterproof dye ink for printing corrugated paper according to claim 1, characterized in that: The organic solvent comprises a first organic solvent and a second organic solvent, wherein the first organic solvent is at least one of ethylene glycol and glycerol; the second organic solvent is a solvent having a solubility parameter in the range of 15 (J / m 3 ) 1 / 2 Up to 20(J / m 3 ) 1 / 2 At least one of an ester solvent and an ether solvent.

4. The waterproof dye ink for printing corrugated paper according to claim 3, characterized in that: The second organic solvent includes an ester solvent and an ether solvent. In terms of mass percentage, the content of the ester solvent is 1% to 3%, and the content of the ether solvent is 1% to 3%.

5. The waterproof dye ink for printing corrugated paper according to claim 1, characterized in that: In terms of mass percentage, the content ratio of the organic solvent to the colorant is 1:1 to 2:

1.

6. The waterproof dye ink for printing corrugated paper according to any one of claims 1 to 5, characterized in that: The waterproof dye ink for printing corrugated paper further comprises a surfactant, wherein the surfactant comprises a polyether siloxane-based surfactant and / or a nonionic surfactant.

7. The waterproof dye ink for printing corrugated paper according to any one of claims 1 to 5, characterized in that: The waterproof dye ink for printing on corrugated paper also includes a pH regulator, which is triethanolamine. The pH of the waterproof dye ink for printing on corrugated paper is 7 to 9.

8. The waterproof dye ink for printing corrugated paper according to any one of claims 1 to 5, characterized in that: Calculated by mass percentage, the waterproof dye ink for printing corrugated paper includes 20% to 45% of a colorant, 30% to 45% of an organic solvent, 0.1% to 0.5% of a surfactant, 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.5% of a pH regulator and the remainder of water.

9. A method for preparing a waterproof dye ink for printing on corrugated paper, characterized in that: Used to prepare a waterproof dye ink for printing corrugated paper as claimed in any one of claims 1 to 8, the preparation method comprises the following steps: S1. Add 30% to 45% of organic solvent, 0.1% to 0.5% of surfactant, 0.1% to 0.3% of antibacterial agent, 0.1% to 0.3% of pH regulator and water into a stirring bucket by mass percentage, and stir for 15 to 45 minutes at a speed of 500 to 800 rpm until the solution becomes uniform and transparent; S2, adding the pigment into the above solution, maintaining the rotation speed of step S1, and continuing stirring for 30min to 60min to evenly disperse the resin in the solution; S3, adding a water-soluble polymer dye to the solution prepared in step S2, maintaining the rotation speed of step S1, and continuing stirring for 45 minutes to 60 minutes to obtain the waterproof dye ink for printing on corrugated paper.

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