Waterproof dye ink for corrugated paper and preparation method thereof

Abstract

The present application provides a kind of corrugated paper with printing waterproof dye ink and its preparation method, the corrugated paper with printing waterproof dye ink includes colorant, organic solvent and surfactant, wherein the colorant includes water-soluble polymer dye and pigment, the hydrophobic end of water-soluble polymer dye and pigment are attached to the surface of corrugated paper to form a physical barrier, which cooperates to overcome the poor water resistance of dye ink and the insufficient brilliance of pigment ink.The content ratio of pigment to water-soluble polymer dye is 3:1 to 15:1 by mass percentage. The water-soluble polymer dye and pigment ensure the bright color of the ink, while improving the water resistance, light resistance and compatibility of the ink.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of digital inkjet printing, and in particular to a kind of waterproof dye inkjet printing for corrugated paper and a preparation method thereof. BACKGROUND

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

[0003] At present, the main water-based inkjet ink is used in the corrugated paper digital printing scheme on the market, which has the advantage of green environmental protection. 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, scratch resistance and waterproof performance on corrugated paper because the coloring agent is pigment, which is insoluble in water, and contains resin as an adhesive. However, the color saturation of pigment is relatively low, which is difficult to meet the requirements of color saturation in corrugated paper box.

[0005] Water-based dye ink has bright color, which basically meets or reaches the traditional color saturation. However, due to the water-soluble molecules of dye, it has the defect of poor waterproof performance, and the light resistance is not strong, which cannot meet the demand of outdoor application. One of the current improvement methods is to add a post-process (such as adding varnish, wax emulsion, etc.) to waterproof after inkjet printing, which leads to complex process and higher cost. Or by adding modified polyurethane and acrylic ester resins in the ink composition, a resin film is formed on the surface of the ink to achieve excellent waterproof performance, but there is a problem of poor compatibility of the ink.

[0006] Therefore, it is necessary to develop a kind of inkjet waterproof dye ink that meets the color requirements and ensures the waterproof and light resistance performance and compatibility. SUMMARY

[0007] The first object of the present application is to provide a kind of inkjet waterproof dye ink for corrugated paper, which solves the problem that the existing inkjet waterproof dye ink for corrugated paper cannot meet the color, waterproof and light resistance performance and compatibility at the same time.

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

[0009] To achieve the first object of the present application, the present application provides a kind of corrugated paper with printing waterproof dye ink, which includes colorant, organic solvent and surfactant, wherein the colorant includes water-soluble polymer dye and pigment, the water-soluble polymer dye has hydrophobic end, and the content ratio of pigment to 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 dye is a kind of colored high molecular compound which combines dye and polymer backbone by covalent bond. This combination mode gives polymer dye double functions: it has high strength, easy film-forming property and other characteristics of high molecule, and also has selective light absorption and multicolor of dye. The mutual entanglement and crosslinking of polymer chain enable dye molecules to arrange closely together, forming continuous and uniform film layer, thus showing good film-forming property. Secondly, because polymer dye has huge molecular weight and belongs to high polymer category, its binding force with fiber is very high. This strong binding force makes dye molecules not easy to migrate or fall off when heated or subjected to other external forces, thus showing excellent migration resistance and color fastness. At the same time, the thermal stability of polymer chain is good, and it can maintain the stability of structure at high temperature, thus giving polymer dye good heat resistance. The water-soluble polymer dye in the present application contains hydrophobic end, which reduces the penetration and diffusion of water molecules by introducing hydrophobic group or using crosslinking structure, thus enhancing the water resistance of dye. In order to further enhance the waterproof performance of ink, pigment is added to the colorant at the same time. Pigment is a fine powder-like colored substance, and its water resistance is excellent. In addition, its surface is treated with surfactant or dispersant. When added to water-soluble polymer dye with hydrophobic end, it can ensure that the stability of ink is not affected, and when the ink is printed on corrugated paper and dried, the pigment powder fixed on the surface of the carton will form a physical barrier, avoiding water from penetrating into the dyed substance, thus further improving the waterproofness of the ink. On the other hand, the dye is modified to form water-resistant polymer dye, the color shade becomes lighter, and the penetration on the carton is relatively strong. The addition of a certain proportion of pigment enhances the waterproofness while enhancing the color brightness. Since pigment provides color stability and hiding power, and dye can produce stronger and more transparent color, the combination use can create color effect with both hiding power and transparency. In addition, the strong light resistance of pigment helps to enhance the light resistance of the ink. However, the content ratio of pigment to water-soluble polymer dye is 3:1 to 15:1, because the waterproofness of ink depends on the content of pigment in ink, and the brightness of color depends entirely on the content of water-soluble polymer dye in ink. If the content of pigment is too high, the ink is prone to appear insoluble, and the color on the carton will appear uneven and the touch feeling will be poor. If the content of pigment is too low, the waterproof performance of the ink is not excellent enough.

[0011] Further, the water-soluble polymer dye is a water-soluble polymer dye with multiple hydroxyl groups, and is specifically selected from at least one of Yellow R-01, Red R-01, Blue R-01 and Black R-01; and the pigment is an organic pigment, and is specifically selected from at least one of phthalocyanine blue 15:3, pigment red 122, pigment yellow 155, and pigment black 7.

[0012] As can be seen from the above solutions, the water-soluble polymer dye of the above type mainly forms hydrogen bonds between the hydroxyl groups in the dye and the cellulose molecules on the surface of the corrugated paper, so that the dye can better adhere to the surface of the corrugated paper, and the color fastness is high.

[0013] Further, 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; and the second organic solvent is at least one of an ester solvent and an ether solvent with a solubility parameter ranging from 15 (J / m 3 ) 1 / 2 to 20 (J / m 3 ) 1 / 2 . The ester solvent is at least one of butyl acetate, dipropylene glycol methyl ether acetate, and 3-methoxypropyl methyl acetate; and the ether solvent is at least one of propylene glycol monomethyl ether and a dialkyl ether.

[0014] As can be seen from the above solutions, the first organic solvent has good moisturizing properties, which can avoid the phenomenon of dry head of ink during printing, but cannot effectively dissolve the water-soluble polymer dye and the pigment. The second organic solvent includes ether and ester solvents, which have better solubility and can better dissolve the colorant, and The series of polymer dyes and polyester / polyether have high compatibility, thereby improving the uniformity of dyeing; the ether and ester solvents can also promote the chemical reaction between the dye and the fiber, thereby improving the fixation rate and color fastness of dyeing; in addition, when selecting, the solubility parameter of the solvent should be considered. The solvent with a low solubility parameter has relatively weak solubility, and the solvent with a high solubility parameter may have high volatility, which affects the environment.

[0015] Further, the second organic solvent includes an ester solvent and an ether solvent, and the content of the ester solvent is 1% to 3% by mass percentage, and the content of the ether solvent is 1% to 3% by mass percentage.

[0016] As can be seen from the above scheme, too little organic solvent can cause the macromolecular dye and pigment to be unable to be uniformly dispersed, thereby affecting the stability of the ink, the compactness and water resistance of the ink coating, and the dye existing in the dyeing solution in the form of a suspension, which is prone to particle size growth, aggregation, coagulation and even precipitation at high temperature dyeing, thereby affecting the uniformity and color fastness of dyeing; too much organic solvent can excessively dissolve the dye, resulting in a light color or high permeability phenomenon. This is mainly because the ester-based auxiliary has strong solubility and permeability, and after printing, the ink can enter the interior of the fiber from the surface of the fiber through the expanded capillary of the fiber, resulting in a light color of the printed carton. The ether-based and ester-based solvents have good permeability on the carton and have a large impact on the color. Therefore, under the above proportion, the ink has good water resistance, color fastness, color brightness and uniformity.

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

[0018] Further, the corrugated paper inkjet waterproof dye ink further comprises a surfactant, the surfactant comprises 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; and 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 resistance to acid and alkali and hydrolysis, which is important for improving the hydrolysis resistance and weather resistance of the ink coating; the polyether-modified siloxane molecule has a small size and excellent wetting property, can effectively penetrate into the small gaps on the surface of the pigment, form a uniform wetting film on the surface, and can improve the dispersibility of the pigment in the ink system and the wetting property of the ink itself. In addition, the polyether siloxane has both hydrophobicity and hydrophilicity, the hydrophobic group can connect the colorant, reduce the surface tension thereof, the hydrophilic group connects water, and the stability of the ink is enhanced. At the same time, the unique structure and properties of the polyether siloxane surfactant provide super-hydrophobicity and super-hydrophilicity, can form a waterproof coating on the ink coating, and further enhance the waterproof effect.

[0020] Further, the corrugated paper inkjet waterproof dye ink further comprises a pH adjuster, the pH adjuster is triethanolamine, and the pH of the corrugated paper inkjet waterproof dye ink is 7 to 9.

[0021] As can be seen from the above scheme, the dye is greatly affected by the pH value during printing, when the pH is too low, the cellulose fiber in the corrugated paper cannot be ionized to form a covalent bond with the dye, resulting in a light color after printing; when the pH is too high, the water solubility of the dye rapidly decreases; the ink has good printing effect in the above pH range.

[0022] Further, the corrugated paper inkjet waterproof dye ink includes 20-45% colorant, 30-45% organic solvent, 0.1-0.5% surfactant, 0.1-0.3% antibacterial agent, 0.1-0.3% pH regulator and the balance of water.

[0023] As can be seen from the above solutions, the corrugated paper inkjet waterproof dye ink has excellent dyeing effect, good waterproofness and solves the problem of poor compatibility of water-soluble polymer dye in the ink.

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

[0025] The present application provides a corrugated paper inkjet waterproof dye ink, which includes 20-45% colorant, 30-45% organic solvent, 0.1-0.5% surfactant, 0.1-0.3% antibacterial agent, 0.1-0.3% pH regulator and the balance of water in terms of mass percentage.

[0026] The colorant includes water-soluble polymer dye and 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. Preferably, the water-soluble polymer dye is a water-soluble polymer dye with multiple hydroxyl groups, which is selected from at least one of Yellow R-01, Red R-01, Blue R-01 and Black R-01.

[0027] The pigment is an organic pigment, and is at least one selected from 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 is at least one of an ester solvent and an ether solvent with a solubility parameter ranging from 15 (J / m 3 ) 1 / 2 to 20 (J / m 3 ) 1 / 2 ). The ester solvent is at least one selected from butyl acetate, dipropylene glycol methyl ether acetate, and 3-methoxypropyl methyl acetate, and the ether solvent is at least one selected from propylene glycol monomethyl ether and a dialkyl ether. Preferably, the second organic solvent includes the ester solvent and the ether solvent, the content of the ester solvent is 1% to 3% by mass percentage, the content of the ether solvent is 1% to 3% by mass percentage, and the content ratio of the organic solvent to the colorant is 1:1 to 2:1.

[0029] The surfactant is a polyether siloxane surfactant, specifically at least one selected from WET 240, WET 250, WET 260, and WET 270, and a nonionic surfactant surfynol-465.

[0030] The antibacterial agent is selected from carboxin.

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

[0032] The present application provides a preparation method of a waterproof dye ink for corrugated paper by jet printing, for preparing the above-mentioned waterproof dye ink for corrugated paper by jet printing, the preparation method comprising the following steps:

[0033] S1, 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 are added to a stirring barrel in mass percentage, and stirred at a speed of 500 rpm to 800 rpm for 15 min to 45 min until the solution becomes uniform and transparent;

[0034] S2, the pigment is put into the above-mentioned solution, the speed of step S1 is maintained, and stirring is continued for 30 min to 60 min, so that the resin is uniformly dispersed in the solution;

[0035] S3, a water-soluble high molecular dye is added to the solution prepared in step S2, the speed of step S1 is maintained, and stirring is continued for 45 min to 60 min, to obtain the waterproof dye ink for corrugated paper by jet printing.

[0036] The following is described in connection with specific embodiments.

[0037] The inkjet waterproof dye ink for corrugated paper was prepared according to the mass percentages shown in Table 1 and Table 2.

[0038] Table 1

[0039]

[0040] Table 2

[0041]

[0042]

[0043] The preparation method is as follows: S1, according to the mass percentages, 30% to 45% of the organic solvent, 0.1% to 0.5% of the surfactant, 0.1% to 0.3% of the antibacterial agent, 0.1% to 0.3% of the PH regulator and water are added into the stirring barrel, and stirred at a speed of 500 rpm to 800 rpm for 15 min to 45 min, until the solution becomes uniform and transparent; S2, the pigment is put into the above-mentioned solution, the speed of step S1 is maintained, and the stirring is continued for 30 min to 60 min, so that the resin is uniformly dispersed in the solution; S3, the water-soluble high molecular dye is added to the solution prepared in step S2, the speed of step S1 is maintained, and the stirring is continued for 45 min to 60 min, to obtain the inkjet waterproof dye ink for corrugated paper.

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

[0045] The performance of the above examples and comparative examples is tested.

[0046] 1. Stability test

[0047] (1) Aging test: the ink is placed in a 60℃ environment for one week and two weeks of aging test, and the viscosity and surface tension are tested, and the viscosity and surface tension change rate ≤10% is considered to be qualified.

[0048] (2) Freezing test: the ink is placed in a-18℃ environment for three days of freezing test, and the viscosity and surface tension are tested, and the viscosity and surface tension change rate ≤10% is considered to be qualified.

[0049] (3) Insoluble matter test: 100g of ink is subjected to aging and freezing (the ink is placed in a-18℃ environment) for three days, and the aged ink is placed at room temperature, subjected to negative pressure 0.45PP membrane filtration, and whether there is insoluble matter on the filter screen is observed, and no insoluble matter or a small amount of insoluble matter is considered to be qualified.

[0050] 2. Smoothness test

[0051] The ink EPSON I3200 nozzle was used as the test nozzle, and the nozzle state was tested after continuous printing of 100 m. The number of broken nozzles of less than 3 was considered to be qualified in terms of smoothness.

[0052] 3. Waterproof performance test

[0053] The printed color block was soaked in water for 2 hours, and the color density before and after soaking was tested. The attenuation rate of less than 10% was considered to be qualified.

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

[0055] Table 3

[0056]

[0057]

[0058] Table 4

[0059]

[0060]

[0061] From the above test results, it can be seen that Comparative Example 1 did not add organic pigments relative to Example 1, and it can be seen that the performance in terms of printing smoothness and waterproof performance is not as good as Example 1; Comparative Example 2 reduced the amount of organic pigments relative to Example 1, and the mass ratio of pigments to water-soluble polymer dyes was less than 3:1-15:1, and it can be seen that the waterproof performance is not as good as Example 1; Comparative Example 3 did not add dyes relative to Example 4, and the ink had insoluble substances, and the printing smoothness performance was not as good as Example 1; Comparative Example 4 reduced the amount of water-soluble polymer dyes relative to Example 4, and the mass ratio of pigments to water-soluble polymer dyes was greater than 3:1-15:1, and the ink had insoluble substances, and the printing smoothness performance and waterproof performance were not as good as Example 4; Comparative Example 5 reduced the amount of organic solvent relative to Example 2, and the mass ratio of organic solvent to colorant was less than 1:1-2:1, and the ink had insoluble substances, and the printing smoothness performance and waterproof performance were not as good as Example 2; Comparative Example 6 increased the amount of organic solvent relative to Example 3, and the mass ratio of organic solvent to colorant was greater than 1:1-2:1, and the ink printing smoothness performance and waterproof performance were not as good as Example 3; Comparative Example 7 reduced the amount of ester solvent relative to Example 2, and the ester content was less than 1%-3%, and the ink had insoluble substances, and the printing smoothness performance and waterproof performance were not as good as Example 2; Comparative Example 8 increased the amount of ester solvent relative to Example 3, and the ester content was greater than 1%-3%, and the waterproof performance was not as good as Example 3.

[0062] In summary, the present application provides a kind of printing waterproof dye ink for corrugated paper, with waterproof property.The present application first utilizes water-soluble polymer dye, bonds dye on polyurethane, forms polyurethane molecular chain, and the hydrophobic group of polyurethane molecular chain constructs the first waterproof barrier.Further, by adding organic pigment molecules into colorant, the waterproof performance of organic pigment particles is excellent enough, and also forms physical barrier on the surface of corrugated paper, so that the waterproof effect of ink is further enhanced.Secondly, when water-soluble polymer dye with hydrophobic end and organic pigment are added into solution with water as main solvent, ink will have incompatibility phenomenon, affecting printing fluency.Therefore, two kinds of organic solvents are added in this paper, and organic solvents (polyester, polyether) with larger solubility coefficient value are used to effectively dissolve water-soluble polymer dye and pigment.Finally, in order to achieve the result of bright color, the ratio of water-soluble polymer dye and pigment is optimized, the main reason is that the color of dye will become lighter after modification and the permeability of dye on the surface of corrugated paper is relatively strong, so by adding a certain proportion of organic pigment, the color effect can be enhanced.At the same time, the ratio of organic solvent and colorant is controlled to avoid color migration, and the color effect is deepened.Further, ether and ester solvents can promote the reaction of dye and paper fiber, can improve the dye uptake of ink, and further enhance the dyeing effect.

[0063] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of various changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application.The protection scope of the present application should be subject to the protection scope of claims.

Claims

1. A waterproof dye ink for printing on corrugated paper, characterized by: The waterproof dye ink for printing corrugated paper comprises 20% to 45% of a colorant, 30% to 45% of an organic solvent, and 0.1% to 0.5% of 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 by mass percentage; The water-soluble polymer dye is a water-soluble polymer dye having polyhydroxyl groups; the pigment is an organic pigment; 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 to 20(J / m 3 ) 1 / 2 At least one of an ester solvent and an ether solvent; The second organic solvent includes an ester solvent and an ether solvent. The content of the ester solvent in the waterproof ink for printing corrugated paper is 1% to 3% by mass, and the content of the ether solvent in the waterproof ink for printing corrugated paper is 1% to 3% by mass. Calculated by mass percentage, the content ratio of the organic solvent to the colorant is 1:1 to 2:

1.

2. The waterproof dye ink for printing on corrugated paper according to claim 1, wherein: The waterproof dye ink for printing corrugated paper further comprises a surfactant, which comprises a polyether siloxane-based surfactant and / or a nonionic surfactant.

3. The waterproof dye ink for printing on corrugated paper according to claim 1 or 2, 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.

4. The waterproof dye ink for printing on corrugated paper according to claim 1 or 2, characterized in that: Calculated by mass percentage, the waterproof dye ink for printing corrugated paper includes 0.1% to 0.3% of an antibacterial agent, 0.1% to 0.5% of a pH regulator, and the balance is water.

5. A method for preparing a waterproof dye ink for printing on corrugated paper, characterized in that: For preparing a waterproof dye ink for printing on corrugated paper according to any one of claims 1 to 4, the preparation method comprises the following steps: S1. Add 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 to a stirring bucket by mass. Stir at a speed of 500 to 800 rpm for 15 to 45 minutes until the solution becomes homogeneous and transparent. S2. Add the pigment to the above solution, maintain the rotation speed of step S1, and continue stirring for 30 minutes to 60 minutes to evenly disperse the pigment in the solution; S3. Add a water-soluble polymer dye to the solution prepared in step S2, maintain the rotation speed of step S1, and continue stirring for 45 minutes to 60 minutes to obtain the waterproof dye ink for printing on corrugated paper.

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