Digital printed fabric pretreatment agent as well as preparation method and application thereof

Abstract

The invention provides a digital printing fabric pretreatment agent and a preparation method and application thereof, and relates to the technical field of digital ink-jet printing, the digital printing fabric pretreatment agent comprises the following components by mass: 15%-80% of a cationic polymer, 0.01%-10% of an inorganic salt, 0.01%-15% of a hydrophilic finishing agent, 0.01%-1% of an acidity regulator, and the balance of water; the cationic polymer contains a dye-philic group. The technical problems that in the prior art, a fabric pretreatment agent is insufficient in adsorption efficiency and single in function are solved, and the technical effects that the ink adsorption efficiency, the pattern definition, the color brightness and the color fastness are remarkably improved, and meanwhile the environmental protection property and the process adaptability are considered are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital inkjet printing, and in particular to a digital printing fabric pretreatment agent, a preparation method and application thereof. BACKGROUND

[0002] Due to the hydrophobicity (contact angle > 90°) and chemical inertness of polyester fibers, it is difficult for water-based ink to effectively wet and penetrate. During traditional digital inkjet printing, the ink is prone to spread on the surface of the fiber ("coffee ring effect"), resulting in blurred pattern edges and low color saturation; in addition, due to the lack of fixation sites, dispersed dyes cause severe thermal migration, affecting the washing and rubbing fastness.

[0003] The core functions of the digital printing fabric pretreatment agent include: 1) improving ink affinity, promoting ink adsorption and penetration; 2) controlling ink diffusion, preventing excessive penetration of ink on the fabric surface, and ensuring clear edges, especially for high-precision digital printing, which requires clear patterns; 3) improving color depth and fastness, enhancing the binding force between dyes and fibers, and reducing color fading after washing or rubbing.

[0004] Common fabric pretreatment agents generally include the following categories: one category is sodium alginate, sodium carboxymethyl cellulose or polyacrylate, etc. high molecular polymer, its mechanism of action is to form a thin layer on the surface of the fiber, hinder the gap between the fibers, so as to inhibit the diffusion of ink, at the same time increase the surface roughness to improve the adhesion of ink, but its shortcomings are also obvious, especially when applied to polyester and other chemical fiber fabrics, the color yield of the fabric is shallow, and the color loss is serious after washing; another category is hygroscopic fabric pretreatment agent, its main component contains polyhydric alcohol or hydrophilic surfactant, its function is to increase the hygroscopicity of the fiber, promote the dissolution and diffusion of dye ink, improve the color yield and uniformity. The advantages of this kind of fabric pretreatment agent are that the hand feeling of the finished fabric is not affected, and it is easy to wash off, but the disadvantage is that the adsorption of ink is weak, which can cause penetration and result in low pattern clarity.

[0005] In recent years, the mainstream fabric pretreatment agent, i.e. cross-linked fabric pretreatment agent, for example, uses quaternary ammonium salt cationic compounds to modify the fabric, which adsorbs anionic dyes or dye micelles through electrostatic interaction, thereby increasing the adsorption of dye ink and improving the color depth; its main component can produce cross-linking reaction with the fabric to form covalent bond, so as to enhance the combination of ink and fiber and improve the color fastness; at the same time, the formation of cross-linked network structure further controls the diffusion of ink on the fabric, thereby improving the high definition of inkjet printing. However, this method also has the following defects: 1) Insufficient adsorption efficiency: dye adsorption relying solely on charge interaction is a physical combination, and dye molecules are prone to desorption in subsequent washing or high temperature treatment (dye fixation rate is usually < 70%); 2) Functional single: traditional cationic agents only provide positive charge sites, which cannot be optimized for selective adsorption of different dye structures (such as disperse dyes containing sulfonic acid groups, azo groups) or different charge amounts of dye micelles.

[0006] Therefore, the present application is proposed. SUMMARY

[0007] One of the purposes of the present application is to provide a digital printing fabric pretreatment agent that can significantly improve ink adsorption efficiency, pattern clarity, and color fastness, while also considering environmental friendliness and process adaptability.

[0008] The second purpose of the present application is to provide a preparation method of a digital printing fabric pretreatment agent, which is simple, efficient, and has a high success rate, suitable for industrial production.

[0009] The third purpose of the present application is to provide an application of a digital printing fabric pretreatment agent, which can achieve high ink saving (low longitudinal permeability) and small color depth difference between the back and front of the fabric (high longitudinal permeability) while ensuring high-definition printing patterns.

[0010] In order to achieve the above purposes of the present application, the following technical solutions are adopted: In a first aspect, a digital printing fabric pretreatment agent includes the following components by mass percentage: Cationic polymer 15%-80%, inorganic salt 0.01%-10%, hydrophilic finishing agent 0.01%-15%, acidity regulator 0.01%-1%, and the balance of water; The cationic polymer contains dye-philic groups and has a chemical structure represented by Formula 1 or Formula 2: Formula 1; Formula 2; R is selected from at least one of methyl, phenyl, and styrene phenyl.

[0011] Further, the molecular weight of the cationic polymer represented by Formula 1 is 100,000-2,000,000.

[0012] Further, the molecular weight of the cationic polymer represented by Formula 2 is 100,000-3,000,000.

[0013] Further, the inorganic salt includes at least one of sodium chloride, calcium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate, and magnesium sulfate. Preferably, the inorganic salt is calcium chloride.

[0014] Further, the hydrophilic finishing agent comprises at least one of ethylene glycol, diethylene glycol, glycerol, PEG, urea, isomeric alcohol polyoxyethylene ether, acetylene glycol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and penetrant JFC. Preferably, the hydrophilic finishing agent is penetrant JFC. Preferably, the acidity regulator comprises at least one of glacial acetic acid, citric acid, dilute hydrochloric acid and dilute sulfuric acid. Preferably, the acidity regulator is glacial acetic acid.

[0015] Further, the water comprises deionized water.

[0016] In a second aspect, a preparation method of the digital printing fabric pretreatment agent is provided, comprising the following steps: First, the inorganic salt and the hydrophilic finishing agent are dissolved and mixed with water, and the pH value is adjusted to 3-5 by the acidity regulator, and then the cationic polymer is added and mixed to obtain the digital printing fabric pretreatment agent.

[0017] Further, the cationic polymer shown in formula 1 is obtained by reacting diamine with epichlorohydrin; Preferably, the diamine comprises at least one of dimethylamine, diphenylamine and diphenylstyrylamine.

[0018] Further, the cationic polymer shown in formula 2 is obtained by reacting ammonium chloride monomer with Na4EDTA; Preferably, the ammonium chloride monomer comprises at least one of dimethyl diallyl ammonium chloride monomer, phenyl diallyl ammonium chloride monomer and styrene phenyl diallyl ammonium chloride monomer; Preferably, the ammonium chloride monomer is reacted with Na4EDTA under the action of an initiator; Preferably, the initiator is composed of ammonium persulfate and sodium sulfite.

[0019] In a third aspect, the digital printing fabric pretreatment agent is applied in textile coating digital inkjet printing and dispersion direct spraying digital printing.

[0020] Compared with the prior art, the present application has at least the following beneficial effects: The digital printing fabric pretreatment agent provided by the application can be arranged on the fabric before digital inkjet printing, and the cationic polymer can not only adsorb the ink droplets with negative charge on the surface of the fabric by the cationic property, but also can effectively enhance the adsorption of the ink droplets by the pretreatment agent and the ability of preventing the ink droplets from penetrating horizontally by introducing the dye-favorable groups in the chemical structure and cooperating with the inorganic salt component; the metal cation of the inorganic salt introduced by the application can further enhance the combination of the anion dispersant wrapped outside the dye particles in the dye micelle in the ink droplets, effectively inhibiting the penetration; the cationic polymer can also adjust the vertical penetration of the ink droplets on the surface of the fabric by adjusting the molecular weight and cooperating with the hydrophilic finishing agent; in summary, the pretreatment agent of the application can significantly improve the ink adsorption efficiency, the pattern definition and the color fastness by the synergistic cooperation of the components and the ratio, and can also consider the environmental protection and the process adaptability.

[0021] The preparation method of the digital printing fabric pretreatment agent provided by the application is simple, efficient, has a high success rate and is suitable for industrial production.

[0022] The application of the digital printing fabric pretreatment agent provided by the application can ensure the high definition of the printed pattern, and can also realize the high depth of the pattern color on the surface of the fabric, the saving of ink (low vertical penetration) and the high penetration pattern effect (high vertical penetration) of reducing the color depth difference between the back and the front of the fabric according to different printing requirements. DETAILED DESCRIPTION

[0023] The technical solutions of the application will be described clearly and completely in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0024] According to the first aspect of the application, a digital printing fabric pretreatment agent is provided, which comprises the following components in percentage by mass: The cationic polymer is 15%-80%, the inorganic salt is 0.01%-10%, the hydrophilic finishing agent is 0.01%-15%, the acidity regulator is 0.01%-1%, and the balance is water. The cationic polymer contains dye-favorable groups and has a chemical structure shown in formula 1 or formula 2. Formula 1; Formula 2; R is selected from at least one of a methyl group, a phenyl group and a styrene phenyl group.

[0025] It should be noted that by molecular structure design, the dye affinity group is introduced on the basis of traditional cationization modification, which significantly improves the ink adsorption efficiency, pattern definition and color fastness, while taking into account environmental protection and process adaptability.

[0026] In the present application, the cationic polymer not only can adsorb the ink droplets with negative charge on the surface of the fabric by its cationic property, but also can effectively enhance the adsorption of the ink droplets by the pretreatment agent due to the introduction of the dye affinity group in the chemical structure, in combination with the inorganic salt component, thereby enhancing the ability to prevent ink droplets from penetrating horizontally; at the same time, the cationic polymer can also adjust the vertical penetration of the ink droplets on the surface of the fabric by adjusting the molecular weight, in combination with the hydrophilic finishing agent.

[0027] The typical but non-limiting mass percentage of the cationic polymer is, for example, 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80%; the typical but non-limiting mass percentage of the inorganic salt is, for example, 0.01%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%; the typical but non-limiting mass percentage of the hydrophilic finishing agent is, for example, 0.01%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%; and the typical but non-limiting mass percentage of water is, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%.

[0028] Under the synergistic cooperation of the components and their ratios, the pretreatment agent of the present application achieves the technical effect of significantly improving the ink adsorption efficiency, pattern definition and color fastness, while taking into account environmental protection and process adaptability.

[0029] In a preferred embodiment, the molecular weight of the cationic polymer represented by Formula 1 can be 100-200 million, and the typical but non-limiting molecular weight is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000 million.

[0030] In a preferred embodiment, the molecular weight of the cationic polymer represented by Formula 2 can be 100-300 million, and the typical but non-limiting molecular weight is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, 1800, 2000, 2500, 3000 million.

[0031] In the present application, the inorganic salt includes but is not limited to at least one of sodium chloride, calcium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate and magnesium sulfate, and can be further preferably calcium chloride.

[0032] In the present application, the hydrophilic finishing agent includes, but is not limited to, at least one of ethylene glycol, diethylene glycol, glycerol, PEG, urea, isomeric alcohol polyoxyethylene ether, acetylene glycol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and penetrant JFC, and can be further preferably penetrant JFC.

[0033] In the present application, the water includes, but is not limited to, deionized water.

[0034] According to a second aspect of the present application, a preparation method of the digital printing fabric pretreatment agent described in any one of the above is provided, including the following steps: First, the inorganic salt and the hydrophilic finishing agent are dissolved and mixed with water, and the pH value is adjusted to 3-5 by using an acidity regulator, and then a cationic polymer is added and mixed to obtain the digital printing fabric pretreatment agent.

[0035] The preparation method of the digital printing fabric pretreatment agent of the present application is simple, efficient, has high success rate, and is suitable for industrial production.

[0036] In a preferred embodiment, the cationic polymer represented by formula 1 can be obtained by reacting diamine with epichlorohydrin; wherein the diamine includes, but is not limited to, at least one of dimethylamine, diphenylamine, and diphenylstyrylamine.

[0037] Dimethylamine (or diphenylamine, diphenylstyrylamine) is added to a four-necked flask with a stirrer, placed in an oil bath and controlled to have a temperature of 5-15℃ in the flask, the stirrer is started, and epichlorohydrin is slowly and uniformly dropped, after the dropping is completed, the reaction is continued in a cold water bath for 1-3h, the dimethylamine solution is continuously dropped, after the dropping is completed, the reaction is continued for 0.5-2h, and then the temperature is increased to 30-80℃ and the reaction is continued for 1-5h to obtain a synthetic product, which is the cationic polymer; by controlling the reaction time and the reaction temperature, cationic polymers (formula 1) with different molecular weights can be obtained.

[0038] In a preferred embodiment, the cationic polymer represented by formula 2 can be obtained by reacting an ammonium chloride monomer with Na4EDTA; wherein the ammonium chloride monomer includes, but is not limited to, at least one of dimethyl diallyl ammonium chloride monomer, phenyl diallyl ammonium chloride monomer, and styrene phenyl diallyl ammonium chloride monomer.

[0039] It should be noted that the ammonium chloride monomer and Na4EDTA can react under the action of an initiator, and the initiator can be composed of ammonium persulfate and sodium sulfite.

[0040] Configuration 2g (10g water solution) initiator solution (the mass ratio of ammonium persulfate and sodium sulfite can be 1:1 to reduce the initiation system) is prepared for standby; then 200g of dimethyl (or phenyl, styrene phenyl) diallyl ammonium chloride monomer (60% content) is added into a reaction kettle provided with a reflux condenser, a thermometer and a stirrer, and 0.02g (0.01% of the monomer) of chelating agent Na4EDTA is added; then the pH value of the reaction system is adjusted to 7 by glacial acetic acid; after uniform stirring, the temperature is increased to 80 DEG C, and 1 / 8 of the initiator is added at one time; and the remaining initiator solution is continuously added slowly (within 2h) under the condition of constant temperature at 70 DEG C; then the reaction is kept for 2-3h; after the reaction is completed, the temperature is cooled to 50 DEG C to discharge, and the cationic polymer is obtained; by controlling the variable factors (monomer mass fraction, initiator to monomer dosage ratio and reaction time), cationic polymers (formula 2) of different molecular weights can be obtained.

[0041] According to a third aspect of the present application, the digital printing fabric pretreatment agent of any one of the above is applied in textile coating digital inkjet printing, dispersion direct jet digital printing.

[0042] It should be noted that when the pretreatment agent is applied to textile coating digital inkjet printing, the padding pretreatment agent process is adopted, and the pretreated fabric is dried at 80-105 DEG C, and then placed flat on the coating digital inkjet printer for inkjet printing, after printing, the fabric is dried at 140-180 DEG C for 60-90s using a pressing machine to complete printing; when the pretreatment agent is applied to textile dispersion direct jet digital printing, the padding pretreatment agent process is adopted, and the pretreated fabric is dried at 80-105 DEG C, and then placed flat on the dispersion direct jet digital inkjet printer for inkjet printing, after printing, the fabric is placed at a high temperature of 160-210 DEG C for 1-10min for color development to complete printing.

[0043] In summary, the application of the digital printing fabric pretreatment agent of the present application can ensure high definition of the printed pattern, and can also achieve high ink saving (low longitudinal permeability) and small color depth difference between the back and front of the fabric (high permeability pattern effect) for different printing requirements.

[0044] The application will be further described below by examples. Unless otherwise specified, the materials in the examples are prepared according to the existing method or directly purchased from the market.

[0045] Examples 1-6 Examples 1-6 provide a digital printing fabric pretreatment agent, and the components and their mass percentages are shown in Table 1.

[0046] Table 1

[0047] The cationic polymer used in Examples 1-6 is, in order, respectively: R is methyl; R is phenyl; R is styryl phenyl; R is styryl phenyl; R is phenyl; R is methyl; The inorganic salt is calcium chloride, and the hydrophilic finishing agent is penetrant JFC.

[0048] Example 7 This example provides a digital printing fabric pretreatment agent, which differs from Example 4 only in that the inorganic salt is magnesium chloride; The rest are the same as Example 4.

[0049] Example 8 This example provides a digital printing fabric pretreatment agent, which differs from Example 4 only in that the inorganic salt is potassium sulfate; The rest are the same as Example 4.

[0050] Example 9 This example provides a digital printing fabric pretreatment agent, which differs from Example 4 only in that the hydrophilic finishing agent is ethylene glycol; The rest are the same as Example 4.

[0051] Example 10 This example provides a digital printing fabric pretreatment agent, which differs from Example 4 only in that the hydrophilic finishing agent is isomeric alcohol polyoxyethylene ether; The rest are the same as Example 4.

[0052] Example 11 This example is a method for preparing the digital printing fabric pretreatment agent of Examples 1-10, comprising the following steps: First, the inorganic salt and the hydrophilic finishing agent are dissolved and mixed with water, and the pH value is adjusted to 3-5 with an acidity regulator, then the cationic polymer is added and mixed to obtain a digital printing fabric pretreatment agent.

[0053] Comparative Example 1 This comparative example provides a digital printing fabric pretreatment agent, which differs from Example 4 only in that the cationic polymer is replaced with an equal amount of sodium alginate; The rest are the same as Example 4; The preparation method refers to Example 11.

[0054] Comparative Example 2 This comparative example provides a digital printing fabric pretreatment agent, which is different from Example 4 only in that the cationic polymer is replaced by an equivalent amount of cationic polyacrylamide PAM (molecular weight 500,000); The rest are the same as Example 4; The preparation method refers to Example 11.

[0055] Comparative Example 3 This comparative example provides a digital printing fabric pretreatment agent, which is different from Example 4 only in that the mass percentage of the cationic polymer is 10%, and the amount of deionized water is correspondingly increased; The rest are the same as Example 4; The preparation method refers to Example 11.

[0056] Comparative Example 4 This comparative example provides a digital printing fabric pretreatment agent, which is different from Example 4 only in that the mass percentage of the cationic polymer is 85%, and the amount of deionized water is correspondingly reduced; The rest are the same as Example 4; The preparation method refers to Example 11.

[0057] Comparative Example 5 This comparative example provides a digital printing fabric pretreatment agent, which is different from Example 4 only in that the mass percentage of the inorganic salt is 12%, and the amount of deionized water is correspondingly reduced; The rest are the same as Example 4; The preparation method refers to Example 11.

[0058] Comparative Example 6 This comparative example provides a digital printing fabric pretreatment agent, which is different from Example 4 only in that the mass percentage of the hydrophilic finishing agent is 17%, and the amount of deionized water is correspondingly reduced; The rest are the same as Example 4; The preparation method refers to Example 11.

[0059] Test Example The digital printing fabric pretreatment agents of Examples 1-10 and Comparative Examples 1-6 are tested for performance, and the results are shown in Table 2.

[0060] Performance test method: The pretreatment agent is configured into a water solution with a concentration of 5%, and polyester fabric is treated by one dip and one roll, the roll pressure is adjusted to control the liquid rate to be 56%, and after dipping and rolling, the fabric is dried at 105 DEG C for 5 minutes, then the pretreated polyester fabric is jet printed with a digital printing machine and dispersed direct jet ink to print color block patterns and printing patterns, after printing, the pattern fabric is heat fused to develop color (developing color conditions: 190 DEG C*2min). The color block pattern polyester fabric after jet printing and developing color is tested by a datacolor colorimeter to test the front and back color characteristic values and intensity ratio, each sample is tested 3 times to take average values, and the fabric without pretreatment agent treatment is taken as a blank test standard sample (i.e. the test intensity ratio is 100%), the color block printing sample of the fabric treated by the pretreatment agent is taken as a test comparison sample, and the test intensity ratio is recorded; The printing pattern polyester fabric after jet printing and developing color is observed to test the white background staining and pattern edge definition after fabric washing. The color block pattern polyester fabric after jet printing and developing color is tested by dry and wet rubbing fastness, and the test method refers to GB / T3920-2008 "Textile color fastness test rubbing fastness".

[0061] Table 2

[0062] From the performance data in Table 2, it can be seen that under the synergistic cooperation of the components and their ratios, the ink adsorption efficiency, pattern definition and color fastness are significantly improved, and the technical effects of environmental protection and process adaptability are also considered.

[0063] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A digital printing fabric pretreatment agent, characterized by, Comprise the following components by mass percentage: Cationic polymer 15%-80%, inorganic salt 0.01%-10%, hydrophilic finishing agent 0.01%-15%, acidity regulator 0.01%-1%, and the balance water; The cationic polymer contains dye-philic groups, and has a chemical structure shown in formula 1 or formula 2: Formula 1; Formula 2; R is selected from at least one of methyl, phenyl and styrene phenyl.

2. The digital textile printing pretreatment agent according to claim 1, characterized in that, The cationic polymer shown in formula 1 has a molecular weight of 100-200 million.

3. The digital textile printing pretreatment agent according to claim 1, characterized in that, The cationic polymer shown in formula 2 has a molecular weight of 100-300 million.

4. The fabric pretreatment for digital printing according to any one of claims 1 to 3, characterized in that, The inorganic salt includes at least one of sodium chloride, calcium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate and magnesium sulfate; Preferably, the inorganic salt is calcium chloride.

5. The digital textile printing pretreatment agent according to claim 4, characterized in that, The hydrophilic finishing agent includes at least one of ethylene glycol, diethylene glycol, glycerol, PEG, urea, isomeric alcohol polyoxyethylene ether, acetylene glycol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and penetrant JFC; Preferably, the hydrophilic finishing agent is penetrant JFC; Preferably, the acidity regulator includes at least one of glacial acetic acid, citric acid, dilute hydrochloric acid and dilute sulfuric acid; Preferably, the acidity regulator is glacial acetic acid.

6. The digital textile printing pretreatment agent according to claim 1, characterized in that, The water includes deionized water.

7. A method of preparing the digital printing fabric pretreatment agent according to any one of claims 1 to 6, characterized in that, Comprise the following steps: First, the inorganic salt and the hydrophilic finishing agent are dissolved and mixed with water, and the pH value is adjusted to 3-5 with the acidity regulator, then the cationic polymer is added and mixed to obtain the digital printing fabric pretreatment agent.

8. The preparation method according to claim 7, characterized in that, The cationic polymer shown in formula 1 is obtained by reacting diamine with epichlorohydrin; Preferably, the diamine includes at least one of dimethylamine, diphenylamine and diphenylstyrylamine.

9. The preparation method according to claim 7, characterized in that, The cationic polymer shown in formula 2 is obtained by reacting ammonium chloride monomer with Na4EDTA; Preferably, the ammonium chloride monomer includes at least one of dimethyl diallyl ammonium chloride monomer, phenyl diallyl ammonium chloride monomer and styrene phenyl diallyl ammonium chloride monomer; Preferably, the ammonium chloride monomer reacts with Na4EDTA under the action of an initiator; Preferably, the initiator is composed of ammonium persulfate and sodium sulfite.

10. The digital printing fabric pretreatment agent of any one of claims 1-6 in textile coating digital inkjet printing, dispersion direct spray digital printing.

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