A kind of pretreatment process of digital printing of coating

Abstract

The invention discloses a coating digital printing pretreatment process, comprising applying a treatment liquid containing a cationic liquid on a fabric to obtain a product A with a moisture content of 60% to 80%, and then sequentially performing digital printing, baking and color fixing finishing on the product A, wherein the digital printing ink is an anionic ink, to obtain a finished product. The invention has the characteristics of improving the color yield, color vividness and color fastness of coating ink.

Description

Technical Field

[0001] The invention relates to a digital printing process, in particular to a coating digital printing pretreatment process. Background Art

[0002] Pigment digital printing is a printing method that uses digital technology to print, using pigment inks instead of traditional dye inks for printing.

[0003] The paint ink for paint digital printing uses nano-scale pigments, including pigment particles, resins, solvents, moisturizers and various additives. By adding resins and various additives to the ink, a stable dispersed suspension is formed. During printing, the nozzle is used to spray it onto the surface of the fabric under a certain pressure to achieve the purpose of printing. The pigment particles in the paint ink have no affinity for any fiber. The coloring principle of the paint ink is to rely on the adhesive in it to adhere the pigment particles to the surface of the fiber. The paint ink contains resin, and the nature and content of the resin are crucial to the performance of the paint ink. If the content of resin and pigment particles in the paint ink is too high, it will have a negative impact on the smoothness of the ink printing, while if the content of resin and pigment particles in the paint ink is low, the color fastness and color vividness will be reduced.

[0004] In order to improve the color fastness and color vividness of coating ink without affecting the smoothness of ink printing, the current conventional practice is to perform dry pretreatment on the fabric for coating digital printing, that is, rolling the pretreatment liquid and drying it before printing the coating. However, the fabric produced by this method has a low color yield, insufficient color vividness and saturation, and low color fastness. Summary of the invention

[0005] The object of the present invention is to provide a coating digital printing pretreatment process, which has the characteristics of improving the color yield, color vividness and color fastness of coating ink.

[0006] The technical solution of the present invention is a coating digital printing pretreatment process, which includes applying a treatment liquid containing a cationic liquid on a fabric to obtain a product A with a moisture content of 60% to 80%, and then digitally printing, baking and color fixing the product A in sequence, wherein the ink for digital printing is an anionic ink to obtain a finished product.

[0007] In the aforementioned pretreatment process for digital printing of coatings, the formula of the treatment liquid comprises the following components: 70-90 g / L of cationic liquid, 70-90 g / L of high molecular polymer, and the rest is water.

[0008] In the aforementioned paint digital printing pretreatment process, the method of applying the treatment liquid includes any one of full-width padding, single-sided spraying, partial spraying, single-sided scraping and partial scraping.

[0009] In the aforementioned paint digital printing pretreatment process, the parameters of digital printing include: the number of prints is 2 to 3 times, and the amount of ink used for each print is 228 μL.

[0010] In the aforementioned pretreatment process for digital printing of coatings, the baking temperature is 140-160° C., and the baking time is 3 min-5 min.

[0011] In the aforementioned pretreatment process for digital printing of coatings, the formula of the color fixing agent used for color fixing finishing includes: high-efficiency fastness improving agent T66: 50-70 g / L; softening agent: 20-60 g / L.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The present invention adopts a wet pretreatment process, applies a treatment liquid on the surface of the fabric in advance, and directly digitally prints without drying. The color of the fabric is improved by 30% compared with that after dry pretreatment, the color fastness to washing is improved by 0.5 level, the color fastness to dry friction is improved by 0.5 level, the color fastness to wet friction is improved by 1.5 level, and the multi-fiber staining is improved by half a level as a whole, so as to achieve the effect of simultaneously improving the color vividness and color fastness.

[0014] In particular, the black color fastness to wet friction reaches level 3.5, which solves the biggest problem of paint inkjet digital printing.

[0015] Compared with the dry pretreatment process, the present invention has fewer drying steps, saves operation procedures and time, reduces energy consumption, and lowers production costs.

[0016] Moreover, the printed fabric obtained by the method has a deep color and can reduce the amount of paint and ink used.

[0017] Therefore, the invention has the characteristics of improving the color yield, color vividness and color fastness of the coating ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the appearance of A1 and B1 of the present invention.

[0019] Figure 2 It is a schematic diagram of the wet rubbing and dry rubbing appearance of A1 and B1 of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0021] Embodiment 1:

[0022] A coating digital printing pretreatment process comprises the following steps:

[0023] S1. The semi-bleached cloth is dipped into the treatment liquid to obtain a product A with a moisture content of about 70%. The moisture content is designed so that the treatment liquid contained in the semi-bleached cloth can be fully combined with the coating ink for subsequent printing, and the operation is convenient, which can prevent the treatment liquid from excessively penetrating into the bottom surface of the semi-bleached cloth to cause the surface color of the semi-bleached cloth to be lost, and prevent the treatment liquid from being too little and unable to be fully combined with the coating ink, resulting in uneven dyeing.

[0024] The formula of the treatment liquid is: cationic liquid QM6000: 80g / L; high molecular polymer LS-710B: 80g / L, and the rest is water.

[0025] By adding a high molecular weight polymer to the treatment liquid and utilizing the high molecular weight polymer to enhance the cross-linking effect of the treatment liquid, the coating can be locked more securely.

[0026] S2, digitally print product A to obtain product B;

[0027] Among them, the coating ink for digital printing is anionic liquid, and the formula includes:

[0028] Anionic pigments: K black: 40g / L; Y yellow: 25g / L; C cyan: 20g / L; the solid content of the resin is 168g / L.

[0029] The printing parameters for digital printing are:

[0030] Print twice, and the amount of ink used for each print is 228μL.

[0031] S3, baking product B at 150°C for 3 min to obtain product C;

[0032] S4, dip and roll product C with a color fixing finishing agent, dry it, and perform color fixing and soft finishing to obtain a finished product.

[0033] The formula of the color fixing finishing agent is: high-efficiency fastness enhancer T66: 60g / L; softener: 40g / L, which can improve the color fastness and softness by half a level.

[0034] The present invention performs pre-treatment by impregnation and then does not dry, and directly performs digital printing. Since the wet-rolled treatment liquid contains liquid cationic liquid, and the coating ink is an anionic liquid, they attract and adsorb each other after contact, thereby locking the coating ink, preventing the coating ink from diffusing and bleeding, improving the reaction sufficiency of the coating ink and the treatment liquid, ensuring the clarity of the printing, and at the same time promoting the penetration of the pigment in the coating ink into the interior of the fiber, greatly improving the color fastness and color depth.

[0035] Compared with the dry pretreatment process, the present invention has fewer drying steps, saves operation procedures and time, reduces energy consumption, and lowers production costs.

[0036] Test experiment:

[0037] 1.1 Experimental Materials

[0038] Cotton plain cloth: 50*50 / 144*80. Konica coating ink: K black, Y yellow, C cyan. Coating treatment liquid (cationic liquid) QM6000. High-efficiency fastness enhancer T66.

[0039] 1.2 Equipment: sizing machine, digital printing machine, baking machine, stenter finishing machine.

[0040] 1.3 Process flow:

[0041] Comparative Example 1: Traditional paint digital printing dry pretreatment process, including the following process:

[0042] Semi-bleached cloth---padding treatment liquid---drying---digital printing---baking at 150℃ for 3min--color fixing and soft finishing.

[0043] The treatment solution formula in the rolling treatment solution step is:

[0044] Cationic liquid QM6000: 80g / L; the rest is water.

[0045] The ink formula in the digital printing step is:

[0046] K black: 40g / L; Y yellow: 25g / L; C cyan: 20g / L; Resin: 168g / L.

[0047] The printing parameters in the digital printing step are:

[0048] Print once, and the ink volume used for each print is 335μL.

[0049] The finishing agent formula used in the color fixing and softening finishing step includes:

[0050] Cationic softener: 40g / L.

[0051] Test method:

[0052] The same piece of cloth (acetate, cotton, nylon, polyester, acrylic, wool) was divided into two pieces, A and B, for comparison. Fabric A was subjected to the process of comparative example 1 to obtain dry digital printing fabric A1, and fabric B was subjected to the process of embodiment 1 to obtain wet digital printing fabric B1. A1 and B1 were tested for color light and fastness, and the test results are shown in FIG. Figure 1-2 and Table 1-2.

[0053] from Figure 1As can be seen from Table 1 (cotton 50*50 / 144*80 plain cloth), the color of fabric B1 after wet pretreatment is obviously darker than that of fabric A1 after dry pretreatment, and the F / S value is higher; the color of fabric B1 after wet pretreatment is significantly improved by 30% compared with fabric A1 after dry pretreatment, and the color fastness to washing is improved by 0.5 level, the color fastness to dry rubbing is improved by 0.5 level, and the color fastness to wet rubbing is improved by 1.5 level; Figure 2 (cotton 50*50 / 144*80 plain cloth), it can be seen that there is more color on A1, that is, the color fastness is poor and the color fades more, indicating that the fabric B1 after wet pretreatment has obviously better friction resistance than the fabric A1 after dry pretreatment.

[0054] Table 1. Performance indicators of A1 and B1

[0055]

[0056] Table 2. Washing resistance and staining performance index of different fiber fabrics

[0057]

[0058] It can be seen from Table 2 that the printing process of the present invention improves the multi-fiber staining by half a level compared with the dry printing process.

[0059] The method of the present invention basically meets the requirements of printing color fastness, and is basically the same as the rotary screen coating printing index. There are many ways to apply the pretreatment liquid on the cloth surface, such as full-width padding, single-sided spraying, scraper scraping, and partial spraying and scraping according to the pattern, to prevent the dye from penetrating into the bottom surface and causing the surface color to be lost. It can be selected according to different applications, is flexible to use, and is applicable to many types of cloth.

[0060] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A coating digital printing pretreatment process, characterized in that: The method comprises applying a treatment liquid containing a cationic liquid on the fabric to obtain a product A with a moisture content of 60% to 80%, and then sequentially performing digital printing, baking and color fixing finishing on the product A, wherein the ink for digital printing is an anionic ink, to obtain a finished product.

2. A pigment digital printing pretreatment process according to claim 1, characterized in that: The formula of the treatment liquid includes the following components: 70-90 g / L of cationic liquid, 70-90 g / L of high molecular polymer, and the rest is water.

3. A pigment digital printing pretreatment process according to claim 1, characterized in that: The application method of the treatment liquid includes any one of full-width padding, single-sided spraying, partial spraying, single-sided scraping and partial scraping.

4. A pigment digital printing pretreatment process according to claim 1, characterized in that: The parameters of digital printing include: the number of prints is 2 to 3 times, and the amount of ink used for each print is 228 μL.

5. A pigment digital printing pretreatment process according to claim 1, characterized in that: The baking temperature is 140-160°C, and the baking time is 3-5 minutes.

6. A pigment digital printing pretreatment process according to claim 1, characterized in that: The formula of the color fixing agent used for color fixing finishing includes: high-efficiency fastness improving agent T66: 50-70g / L; softening agent: 20-60g / L.

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