Direct-injection ink for digital printing cotton cloth and preparation method of direct-injection ink

Abstract

The invention provides direct-injection ink for digital printing cotton cloth and a preparation method of the direct-injection ink. The direct-injection ink for the digital printing cotton cloth comprises color paste, resin and a cross-linking agent, the color paste is self-dispersing pigment color paste, and the resin comprises styrene acrylate and polycarbonate type polyurethane. The color paste is self-dispersing pigment color paste, the dispersion stability in an aqueous solution is good, styrene acrylate is introduced on the basis of the self-dispersing pigment color paste, the adsorption capacity on the pigment is further improved, the polyhydric alcohol chain segment in the other resin, namely the poly-carbon type polyurethane, endows the resin with good flexibility, and the color paste is good in dispersion stability in the aqueous solution. The isocyanate chain segment endows the resin with good rubbing fastness. More importantly, under the action of the cross-linking agent, the poly-carbon polyurethane and the styrene acrylate are cross-linked, so that the color density can be further improved; meanwhile, the formed resin film reduces the water absorption and improves the water resistance of the ink.

Description

Technical Field

[0001] The invention relates to the technical field of textile digital inkjet printing ink, and in particular to a digital printed cotton cloth direct-jet ink and a preparation method thereof. Background Art

[0002] Compared with traditional printing, digital printing has the advantages of low energy consumption, simple production process and production flexibility, and is widely used in the textile field. Among them, digital printing of paint is applicable to a wide range of fabrics. After printing, it is baked at high temperature to obtain the finished product, without steaming and washing, which greatly reduces the production cost. However, since the self-ground color paste used in paint ink is a physical effect in which the oily groups on the surface of the colorant are connected to the oily groups of the dispersant, external conditions such as temperature and pressure can easily cause it to break, resulting in the instability of the pigment in water and easy agglomeration, resulting in low ink color brightness, poor color fastness and poor printing fluency. In order to overcome these technical difficulties, further optimization and improvement are needed in terms of chemical composition, manufacturing process and other aspects. Summary of the invention

[0003] The first object of the present invention is to provide a digital printed cotton cloth direct-jet ink, which is used to solve the problems of low color vividness and poor color fastness of existing direct-jet inks.

[0004] The second object of the present invention is to provide a method for preparing a digitally printed cotton cloth direct-jet ink, wherein the method is used to prepare the above-mentioned digitally printed cotton cloth direct-jet ink.

[0005] To achieve the first purpose of the present invention, the present invention provides a digital printed cotton cloth direct-jet ink, which includes a color paste, a resin and a cross-linking agent; the color paste is a self-dispersing pigment color paste, and the resin includes styrene acrylate and polycarbon type polyurethane, wherein the molecular weight of the polycarbon type polyurethane is in the range of 8000 to 12000, and the glass transition temperature of the polycarbon type polyurethane is -20°C to 0°C, the molecular weight of the styrene acrylate is in the range of 1500 to 3000, and the glass transition temperature of the styrene acrylate is greater than 80°C.

[0006] As can be seen from the above scheme, the color paste is a self-dispersible pigment color paste with good dispersion stability in aqueous solution. On the basis of the self-dispersible pigment color paste, styrene acrylate is introduced to further increase the adsorption capacity of the pigment. At the same time, it has good compatibility with other components in the ink, further plays the role of dispersing the pigment and enhancing the stability of the pigment in the aqueous solution. The styrene acrylate with a glass transition temperature greater than 80°C is easy to dry on the surface of the cotton fabric during the printing process to form a microfilm, which helps the pigment to stay on the surface, inhibits the penetration of the ink, and improves the color density. The molecular weight of styrene acrylate is 1500-3000. The small molecular weight is conducive to reducing the viscosity of the color paste, increasing fluidity, and improving the uniformity of the printed color. The glass transition temperature of polycarbon polyurethane is -20°C to 0°C, which can give the ink suitable viscosity and good fluidity. The polyol segment in the polycarbon polyurethane gives the resin good flexibility, and the isocyanate segment gives the resin good rubbing fastness. The molecular weight of polycarbonate polyurethane is between 8000 and 12000. The larger the molecular weight, the better the tensile strength. At the same time, the larger the molecular weight, the longer the molecular chain, the stronger the interaction between molecules, and the water resistance of the ink. Moreover, under the action of the cross-linking agent, polycarbonate polyurethane and styrene acrylate are cross-linked to form a cross-linked network structure, that is, polycarbonate polyurethane wraps styrene acrylate to form a colloid. The formed cross-linked network structure helps the ink to form a film quickly on the surface of the fabric and fix the pigment on the surface. The cross-linked network structure will fill the gaps in the cotton fabric, which is conducive to further improving the color density. At the same time, it inhibits the penetration of water molecules into the film, reduces the water absorption rate, and improves the water resistance of the ink.

[0007] A further solution is that the mass percentage ratio of the resin to the color paste is 1:2 to 1:3; the mass percentage ratio of the resin to the cross-linking agent is 6:1 to 6:2.

[0008] It can be seen from the above scheme that within the above range, the smoothness of printing is guaranteed while improving the ink color density and color fastness.

[0009] A further solution is that the mass percentage of styrene acrylate to color paste is 1:6 to 1:9; the mass percentage of polycarbonate polyurethane to styrene acrylate is 1.5:1 to 2:1.

[0010] It can be seen from the above scheme that the number of particles formed by polycarbonate polyurethane is certain. When too much styrene acrylate is added, several particles will fuse together to wrap more styrene acrylate, resulting in a larger particle size. The increase in particle size leads to a decrease in the double electric layer effect and the repulsive force between ions, which affects storage stability. Too large emulsion particle size will also reduce the resin from entering the fiber gap to form a tighter bond with it, reducing the color density. Within the above range, the particle size is moderate to ensure that the printing color density is not affected.

[0011] A further solution is that the particle size range of the color paste is: D50<130nm, D50~D100: 120~260nm; the particle size range of the polycarbonate polyurethane is: D50<100nm, D50~D100: 80~120nm.

[0012] As can be seen from the above scheme, a narrow particle size distribution range can reduce viscosity and effectively avoid blockage during printing. The reduction in resin particle size enhances the bonding strength between layers and is conducive to uniform printing.

[0013] In a further embodiment, the pigment in the self-dispersible pigment paste is modified with sodium aminophenylphosphate.

[0014] As can be seen from the above scheme, the self-dispersing color paste is modified by aminophenyl phosphate sodium, the phosphate group chemically reacts with the surface of the color powder, the chemical bond formed is not easy to break, and the pigment has good dispersion stability in the water-soluble solution. In addition, the phosphate group is anionic, while the pre-treatment liquid is cationic, which is conducive to anchoring in the fabric and enhancing color fastness.

[0015] In a further embodiment, the cross-linking agent is a blocked isocyanate.

[0016] It can be seen from the above scheme that blocked isocyanate can undergo cross-linking reaction with the resin and the fiber surface, giving the ink good adhesion.

[0017] A further solution is that the digital printed cotton direct-jet ink further comprises a surfactant, and the surfactant is selected from one or more of surfnol 465, surfnol 485, surfnol 604, and surfnol 104E.

[0018] It can be seen from the above scheme that the above surfactant has good wetting properties and can improve the fluidity of the ink and its adhesion to the cloth.

[0019] A further solution is that the digital printed cotton direct-jet ink also includes a solvent, and the solvent is selected from one or more of propylene glycol, propylene glycol, butylene glycol, ethylene glycol, glycerol, diethylene glycol, and polyethylene glycol.

[0020] It can be seen from the above scheme that the above solvent has good moisturizing properties.

[0021] A further solution is that the digital printed cotton direct-jet ink also includes a pH regulator, and the pH regulator is triethanolamine or AMP-95.

[0022] A further solution is that, by mass percentage, the digital printed cotton ink includes 20% to 45% of color paste, 15% to 20% of resin, 0.5% to 2% of surfactant, 0.1% to 0.3% of bactericide, 15% to 50% of solvent, 1% to 10% of cross-linking agent, 0.1% to 0.5% of pH regulator and the balance of deionized water.

[0023] It can be seen from the above scheme that the ink prepared by the above mass percentage has high color vividness and high color fastness.

[0024] In order to achieve the second purpose of the present invention, the present invention provides a method for preparing a digital printed cotton cloth direct-jet ink, which is used to prepare a digital printed cotton cloth direct-jet ink described in any of the above schemes, and the preparation method comprises the following steps: S1: according to mass percentage, 15% to 20% of resin, 0.5% to 2% of surfactant, 0.1% to 0.3% of fungicide, 15% to 50% of solvent, 1% to 10% of cross-linking agent, 0.1% to 0.5% of pH regulator and deionized water are stirred at 800 to 1000 rpm for 30 minutes to 45 minutes; S2: after the above solution is evenly dispersed, 20% to 45% of color paste is added and stirred at 800 to 1000 rpm for 1 hour to 2 hours; S3: after the above solution is filtered, the digital printed cotton cloth direct-jet ink is obtained. DETAILED DESCRIPTION

[0025] The digital printed cotton cloth direct-jet ink provided by the present invention comprises, by mass percentage, 20% to 45% of color paste, 15% to 20% of resin, 0.5% to 2% of surfactant, 0.1% to 0.3% of bactericide, 15% to 50% of solvent, 1% to 10% of cross-linking agent, 0.1% to 0.5% of pH regulator and the balance of deionized water.

[0026] The color paste is a self-dispersible pigment color paste. Preferably, the pigment in the self-dispersible pigment color paste is modified by sodium aminophenylphosphate, and specifically can be selected from one of CAB-O-JET 400B, CAB-O-JET 450C, CAB-O-JET 465M, and CAB-O-JET470Y.

[0027] The resin includes styrene acrylate and polycarbonate polyurethane, wherein the molecular weight of the polycarbonate polyurethane is in the range of 8000 to 12000, and the glass transition temperature of the polycarbonate polyurethane is -20°C to 0°C, and the molecular weight of the styrene acrylate is in the range of 1500 to 3000, and the glass transition temperature of the styrene acrylate is greater than 80°C.

[0028] The crosslinking agent is a blocked isocyanate.

[0029] The surfactant is selected from one or more of surfnol 465, surfnol 485, surfnol 604 and surfnol 104E.

[0030] The solvent is selected from one or more of glycerol, propylene glycol, butylene glycol, ethylene glycol, glycerol, diethylene glycol, and polyethylene glycol.

[0031] The pH regulator is triethanolamine or AMP-95.

[0032] The fungicide can be purchased from Lonza, preferably Natrulon™ PC-15.

[0033] The above materials can all be purchased on the market.

[0034] The mass percentage ratio of the resin to the color paste is 1:2 to 1:3; the mass percentage ratio of the resin to the crosslinking agent is 6:1 to 6:2. The mass percentage ratio of styrene acrylate to the color paste is 1:6 to 1:9; the mass percentage ratio of polycarbonate polyurethane to styrene acrylate is 1.5:1 to 2:1.

[0035] The particle size range of the color paste is: D50<130nm, D50~D100: 120~260nm; the particle size range of the polycarbonate polyurethane is: D50<100nm, D50~D100: 80~120nm.

[0036] The preparation method of the digital printed cotton cloth direct-jet ink of the present invention can be used to prepare the above-mentioned digital printed cotton cloth direct-jet ink, and the preparation method comprises the following steps:

[0037] S1: According to the mass percentage, 15% to 20% of resin, 0.5% to 2% of surfactant, 0.1% to 0.3% of fungicide, 15% to 50% of solvent, 1% to 10% of cross-linking agent, 0.1% to 0.5% of pH regulator and deionized water are stirred at 800 to 1000 rpm for 30 to 45 minutes;

[0038] S2: After the above solution is evenly dispersed, add 20% to 45% of the color paste and stir at 800 to 1000 rpm for 1 to 2 hours;

[0039] S3: The above solution is filtered to obtain digital printing cotton direct-jet ink.

[0040] The present invention will be further described below with reference to the embodiments.

[0041] The digital printing cotton cloth direct-jet ink of the present invention is prepared according to the mass percentage composition shown in Table 1 and Table 2 below.

[0042] Table 1

[0043]

[0044] Table 2

[0045]

[0046]

[0047] According to Table 1 and Table 2 and the above preparation method, black digital direct-jet cotton coating ink, blue digital direct-jet cotton coating ink, magenta digital direct-jet textile coating ink and yellow digital direct-jet textile coating ink of each embodiment and comparative example were prepared.

[0048] The above embodiments and comparative examples were subjected to performance tests.

[0049] 1. Printing Fluency

[0050] The above-prepared ink was printed with an Epson 3200 nozzle. The machine continuously printed 50 meters. If the number of broken holes was less than 3 holes, it was considered qualified. The results are shown in Table 3.

[0051] Table 3

[0052] Example 1 Fluency qualified Comparative Example 1 Failure Example 2 Fluency qualified Comparative Example 2 Failure Example 3 Fluency qualified Comparative Example 3 Fluency qualified Example 4 Fluency qualified Comparative Example 4 Fluency is not qualified Example 5 Fluency qualified Comparative Example 5 Fluency qualified Example 6 Fluency qualified Comparative Example 6 Fluency is not qualified Example 7 Fluency qualified Comparative Example 7 Fluency is not qualified Comparative Example 8 Fluency is not qualified Comparative Example 9 Fluency is not qualified

[0053] 2. Color fastness

[0054] 1. Adhesion test: The printed pattern is subjected to a pressure of 5kg and placed in a 60℃ oven for 24h);

[0055] 2. Dry rubbing fastness test:

[0056] The dry friction cloth is fixed on the friction head, and then 10 reciprocating friction cycles are performed on the printed color strip to observe the color staining on the dry friction cloth. The test results are graded according to the color staining, where: no color on the friction cloth surface: 4-5; the color on the friction cloth surface is lighter: 2-3; the color on the friction cloth surface is dark and covers a wide area: 1-2.

[0057] 3. Wet rubbing fastness test:

[0058] Replace the sample, soak the friction cloth with water, use the squeeze device to ensure that the moisture content of the friction cloth reaches 95% to 100%, use the wet friction cloth to test the dry rubbing fastness, and finally let the wet friction cloth dry naturally and observe the staining on the friction cloth. Test results, the test results are rated according to the staining, where: no color on the friction cloth surface: 4-5; the friction cloth surface color is lighter: 2-3; the friction cloth surface color is dark and covers a wide area: 1-2.

[0059] 4. Washing fastness

[0060] Put the cotton cloth with the printed color strips into 40℃ water, wash for 30 minutes, repeat three times. After washing, dry the wet cotton cloth at 60℃ for three minutes. Use a color density meter to measure the color density and compare it with the color density of the original sample. Rating by color density decay rate, where: decay rate 0%-5%: 4-5; decay rate 5%-10%: 2-3; decay rate greater than 10%: 1-2.

[0061] The test results are shown in Table 4.

[0062] Table 4

[0063]

[0064]

[0065] 3. Color Density

[0066] A color block with 100% ink volume was printed on the printer, and after drying, it was tested using an American X-RITE colorimeter, and the LAB value was recorded. Table 5 shows the color density test results.

[0067] Table 5

[0068]

[0069]

[0070] According to Tables 1 to 5, Comparative Example 1 does not use polycarbonate polyurethane compared to Example 1; Comparative Example 2 does not use blocked isocyanate compared to Example 2; the limited range of the resin: color paste of Examples 3 and 4 is in the range of 1:2 to 1:3, and Comparative Example 3 increases the amount of resin compared to Example 3, and the ratio of resin: color paste is 1:1; Comparative Example 4 changes the ratio between the resin and the color paste compared to Example 4, and the ratio of resin: color paste is 1:4; the limited range of the resin: cross-linking agent of Examples 5 and 6 is in the range of 6:1 to 6:2, and Comparative Example 5 reduces the amount of isocyanate compared to Example 5. The amount of resin: cross-linking agent is about 7:1; the amount of isocyanate is increased in Comparative Example 6 compared with Example 6, and the ratio of resin: cross-linking agent is 2:1; the limited range of polycarbon type polyurethane: styrene acrylate in Example 6 is within the range of 1.5:1 to 2:1, Comparative Example 7 does not use styrene acrylate compared with Example 6, Comparative Example 8 increases the amount of styrene acrylate compared with Example 6, and the ratio of polycarbon type polyurethane: styrene acrylate is 1:1, and Comparative Example 9 increases the amount of polycarbon type polyurethane compared with Example 6, and the ratio of polycarbon type polyurethane: styrene acrylate is 3:1.

[0071] According to the results of fluidity in Table 3, it is shown that the self-dispersing color paste modified by sodium aminophenylphosphate has good stability in the ink, is not easy to agglomerate, and avoids printing clogging; it also shows that the flexibility of polycarbon type polyurethane can give the ink good printing fluidity; exceeding the limited range of polycarbon type polyurethane: color paste and polycarbon type polyurethane: cross-linking agent, the solid content is too high, which will lead to the problem of poor fluidity.

[0072] According to the color fastness results in Table 4, it is shown that the phosphate groups in the self-dispersing color paste enhance the color fastness; the isocyanate segments impart good rubbing fastness to the ink.

[0073] According to the color density results in Table 5, it is shown that the self-dispersing colorant has good dispersibility in the ink, and the further modification of the colorant by styrene acrylate effectively enhances the color density.

[0074] The digital printed cotton direct-jet ink of the present invention utilizes a phosphoric acid group as the modified group of the self-dispersing color paste, has good stability in aqueous solution, and provides excellent color adhesion. On this basis, the pigment affinity group styrene acrylate is added to enhance the stability and color density of the pigment in the solution, and the two synergistically improve the color of the printed pattern. In addition, the polyol segment in the polycarbon polyurethane is used to give the resin good flexibility, corresponding to the appropriate viscosity, and further by reducing the particle size range of the polycarbon polyurethane and the color paste, the risk of plugging is avoided, so that the ink has good printing smoothness. Under the action of the cross-linking agent, the polycarbon polyurethane and styrene acrylate are cross-linked to form a cross-linked network structure, that is, the polycarbon polyurethane wraps the styrene acrylate to form a colloid. The formed cross-linked network structure helps the ink to quickly form a film on the surface of the fabric to fix the pigment on the surface, and the cross-linked network structure will fill the gaps of the cotton fabric, which is conducive to further improving the color density; at the same time, it inhibits the penetration of water molecules into the inside of the film, reduces the water absorption rate, and improves the water resistance of the ink.

[0075] 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 digital printing cotton cloth direct-jet ink, characterized in that: The digital printed cotton direct-jet ink comprises a color paste, a resin and a cross-linking agent; The color paste is a self-dispersing pigment color paste, and the resin includes styrene acrylate and polycarbonate polyurethane; The molecular weight of the polycarbon type polyurethane is in the range of 8000 to 12000, and the glass transition temperature of the polycarbon type polyurethane is -20°C to 0°C; the molecular weight of the styrene acrylate is in the range of 1500 to 3000, and the glass transition temperature of the styrene acrylate is greater than 80°C.

2. A digital printing cotton cloth direct-jet ink as claimed in claim 1, characterized in that: The mass percentage of the resin and the color paste is 1:2 to 1:3; The mass percentage of the resin and the cross-linking agent is 6:1 to 6:

2.

3. A digital printing cotton cloth direct-jet ink as claimed in claim 1, characterized in that: The mass percentage of the styrene acrylate and the color paste is 1:6 to 1:9; The mass percentage of the polycarbonate polyurethane and the styrene acrylate is 1.5:1 to 2:

1.

4. A digital printing cotton cloth direct-jet ink as claimed in claim 1, characterized in that: The pigment in the self-dispersible pigment paste is modified by sodium aminophenylphosphate.

5. A digital printing cotton cloth direct-jet ink according to any one of claims 1 to 4, characterized in that: The cross-linking agent is a blocked isocyanate.

6. A digital printing cotton cloth direct-jet ink according to any one of claims 1 to 4, characterized in that: The digital printed cotton cloth direct-jet ink further comprises a surfactant, and the surfactant is selected from one or more of surfnol 465, surfnol 485, surfnol 604, and surfnol 104E.

7. A digital printing cotton cloth direct-jet ink according to any one of claims 1 to 4, characterized in that: The digital printing cotton cloth direct-jet ink also includes a solvent, and the solvent is selected from one or more of propylene glycol, propylene glycol, butylene glycol, ethylene glycol, glycerol, diethylene glycol, and polyethylene glycol.

8. A digital printing cotton cloth direct-jet ink according to any one of claims 1 to 4, characterized in that: The digital printed cotton direct-jet ink further comprises a pH regulator, and the pH regulator is triethanolamine or AMP-95.

9. A digital printing cotton cloth direct-jet ink according to any one of claims 1 to 4, characterized in that: Measured by mass percentage, the digital printed cotton ink includes 20% to 45% of color paste, 15% to 20% of resin, 0.5% to 2% of surfactant, 0.1% to 0.3% of fungicide, 15% to 50% of solvent, 1% to 10% of cross-linking agent, 0.1% to 0.5% of pH regulator and the balance of deionized water.

10. A method for preparing a digitally printed cotton direct-jet ink, the method being used to prepare a digitally printed cotton direct-jet ink as claimed in any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: S1: According to the mass percentage, 20% to 45% of the color paste, 15% to 20% of the resin, 0.5% to 2% of the surfactant, 0.1% to 0.3% of the fungicide, 15% to 50% of the solvent, 1% to 10% of the cross-linking agent, 0.1% to 0.5% of the pH regulator and the balance of deionized water are stirred at 800 to 1000 rpm for 30 to 40 minutes; S2: After the above solution is evenly dispersed, add 20% to 45% of the color paste and stir at 800 to 1000 rpm for 1 to 2 hours; S3: The above solution is filtered to obtain digital printing cotton direct-jet ink.

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