Fabric preparation method with one bath of digital printing sizing and bottom dyeing

Abstract

The invention discloses a digital printing sizing and bottom dyeing one-bath fabric preparation method which comprises the following steps: A, pretreating a semi-bleaching fabric to obtain a product A; b, sizing and bottom dyeing one-bath treatment is conducted, specifically, the product A is padded in sizing dye liquor, the sizing dye liquor is prepared from 5-50 g / L of reactive dye, 30-100 g / L of urea, 20-30 g / L of baking soda, 2-8 g / L of reserve salt and 10-35 g / L of sodium alginate, and a product B is obtained; c, carrying out digital printing and low-temperature treatment on the product B to obtain a product C; d, steaming and fixing the product C to obtain a finished product. Through the synchronous sizing and bottom dyeing process, bottom dyeing is synchronously completed during digital printing sizing, the problem that the reverse side is exposed is solved, and the method has the advantages of being short in technological process, stable in colored light, capable of saving energy, environmentally friendly and high in production efficiency.

Description

Technical Field

[0001] This invention relates to a method for preparing digitally printed fabrics, and more particularly to a method for preparing fabrics in which digital printing sizing and dyeing are carried out in the same bath. Background Technology

[0002] With the rapid development of technology, digital printing has achieved significant breakthroughs in printing speed, precision, and production costs, leading to a continuous increase in the market share of digitally printed fabrics. However, digitally printed fabrics are generally single-sided printed, with the reverse side appearing white (white showing on the reverse). This is because when digital printing ink is sprayed onto the fabric, it is limited to the surface and cannot penetrate into the fibers. When there are lint or other impurities on the fabric surface (lint is very common in cotton, rayon, linen, etc.), it prevents the ink from being sprayed onto the fabric. After washing, the lint is removed, resulting in undyed white spots, which reduces the quality of the product and makes it lack texture. To improve the quality of printed fabrics and ensure that both sides of the fabric are colored or that the pattern on the front of the fabric is printed through to the reverse side, a multi-step process of "dyeing the base → fixing the color → sizing → printing" is usually adopted, that is, first dyeing the base, then sizing, and finally printing.

[0003] However, the aforementioned processes not only increase production time and costs, but also result in lengthy processes, low production efficiency, high energy consumption, and large consumption of water, electricity, and steam. Furthermore, "dyeing" and "sizing" are two functional units that are strictly separated in time and space. The goal of dyeing is to allow the dye to fully combine with and fix the fiber, requiring a complete dyeing chemical process. The goal of sizing, on the other hand, is to make the fabric alkaline and form a thin film to prevent ink bleeding. These two processes have contradictory or even conflicting requirements regarding chemical concentration, pH value, and temperature. For example, adding the paste too early will hinder the diffusion of dye into the fiber, while insufficient fixation after dyeing before sizing will lead to damage to the base color in subsequent processes. Evaporation under alkaline conditions causes partial hydrolysis of the reactive dyes in the base dye, resulting in a lighter base color after washing (accompanied by color change or edge-to-center color difference), thus causing severe unevenness and color deviation on the fabric surface. The dyeing and printing results are as follows... Figure 1 As shown, Figure 1 In Figure A, the fabric is dyed, and in Figure B, the fabric is dyed and then digitally printed. After comparison, it was found that the fabric in Figure B is much lighter and redder than the fabric in Figure A, with a color difference of only 2-3 levels.

[0004] Therefore, when reactive dyeing and sizing are processed separately, it is difficult to control the color stability, which can easily lead to problems such as color deviation, lightening of the base color, color difference between the edge and center of the fabric, and white spots on the fabric surface. The deviation is 20-35%, which seriously affects the reliability of product quality.

[0005] Moreover, the above-mentioned processes generate a large amount of wastewater during production, putting significant pressure on environmental protection. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing fabrics in which digital printing sizing and base dyeing are performed simultaneously. This invention achieves simultaneous sizing and base dyeing during digital printing sizing, solving the problem of white showing on the reverse side. It also features a short process flow, stable color, energy saving, environmental friendliness, and high production efficiency.

[0007] The technical solution of this invention: A method for preparing fabric by simultaneously applying digital printing sizing and dyeing the base material, comprising the following steps: A. Pre-treat the semi-bleached fabric to obtain product A; B. Sizing and dyeing treatment in the same bath: Immerse product A in sizing dyeing solution. The composition of sizing dyeing solution includes: 5-50g / L of reactive dye, 30-100g / L of urea, 20-30g / L of sodium bicarbonate, 2-8g / L of anti-dyeing salt and 10-35g / L of sodium alginate to obtain product B. C. Digitally print product B and treat it at low temperature to obtain product C; D. Steam product C to fix its color, and obtain the finished product.

[0008] In the aforementioned method for preparing fabrics by simultaneously applying digital printing sizing and dyeing the base, the fabric in step A is pure cotton fabric, linen fabric, regenerated cellulose fabric, or blended fiber fabric.

[0009] In the aforementioned method for preparing fabrics by simultaneously applying sizing and dyeing the base material in digital printing, the reactive dye used in step B is an alkali-resistant dual-reactive dye. For example, Huntsman's Remazol series and DyStar's Drimarene series have alkali resistance and high reactivity.

[0010] In the aforementioned method for preparing fabrics by simultaneously applying sizing and dyeing the base in digital printing, in step B, the urea concentration is 50-80 g / L and the baking soda concentration is 22-28 g / L.

[0011] In the aforementioned method for preparing fabrics by simultaneously applying digital printing sizing and dyeing the base material, the low-temperature treatment in step C is 60-100℃, and the treatment time is ≤3min.

[0012] In the aforementioned method for preparing fabrics by simultaneously bathing digital printing sizing and dyeing, the printing ink used in step C for digital printing is a reactive dye with dual reactive groups.

[0013] In the aforementioned method for preparing fabrics using digital printing with simultaneous sizing and dyeing, the printing ink in step C, by weight, comprises: 5-15 parts of co-solvent, 10-25 parts of humectant, 5-20 parts of reactive dye with dual reactive groups, and 0.5-2 parts of pH buffer. The printing ink is commercially available or formulated according to a known recipe; its specific proportions can be adjusted based on the brand and color.

[0014] In the aforementioned method for preparing fabrics by simultaneously applying digital printing sizing and dyeing the base material, the co-solvent in step C is N-methyl-2-pyrrolidone.

[0015] In the aforementioned method for preparing fabrics by simultaneously applying digital printing sizing and dyeing the base material, the humectant in step C is glycerin and / or diethylene glycol.

[0016] In the aforementioned method for preparing fabrics by simultaneously applying digital printing sizing and dyeing the base material, step D specifically involves: fixing product C by steaming at 100-103℃ for 8-12 minutes to obtain the finished product.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a simultaneous sizing and dyeing process to complete the dyeing process simultaneously during digital printing sizing. In the unfixed state, through precise formula design, the dyeing system and the sizing system coexist in the same bath, delaying the color fixation reaction. Ultimately, simultaneous color fixation is achieved after printing, solving the problem of white showing on the reverse side and avoiding the color instability defects of traditional dyeing processes, with a hue deviation of <5%.

[0018] Specifically, a higher dosage of urea (30-100g / L) is used in the sizing and dyeing process. In addition to acting as a co-solvent and hygroscopic agent for the dye, it can form a high-concentration "protective" liquid environment during drying, creating a uniform and stable base color. This greatly reduces dye hydrolysis and the migration and aggregation of dye molecules to the fiber surface (i.e., "migration") caused by moisture evaporation. This fundamentally solves the problems of "white spots on the fabric surface" and "color difference between the edge and the center" caused by dye hydrolysis and migration in traditional dyeing processes.

[0019] In the simultaneous sizing and dyeing process, baking soda (20-30 g / L) is used in conjunction with a large amount of urea (30-100 g / L) and sodium alginate paste (10-35 g / L). During the low-temperature treatment stage, excess water is removed, dye migration is inhibited, and the activity of the alkali is delayed rather than completely fixed, creating conditions for subsequent simultaneous color fixing. Only in the subsequent steaming stage does the baking soda work together with the printing ink to promote the simultaneous covalent bonding of the base dye in the sizing solution and the pattern dye in the printing ink with the fiber for color fixing. This "simultaneous color fixing" mechanism is the fundamental reason why color deviation has been reduced from 20-35% in traditional processes to <5%.

[0020] This invention eliminates the dyeing and color-fixing processes, shortens the production process, saves 30-50% of water, reduces overall energy consumption by more than 30%, significantly reduces water, electricity and steam consumption, and improves production efficiency while saving energy and protecting the environment.

[0021] The fabric obtained by this invention has a uniform base color, fine pattern, soft hand feel, and a washing fastness of 3.5 for dark colors and 4 for light colors, indicating high quality.

[0022] This invention is applicable to cotton, linen, regenerated cellulose fabrics and blended fabrics, with no quantity limit, suitable for multi-variety production, and has wide applicability. Attached Figure Description

[0023] Figure 1 These are images of printed fabrics made using traditional techniques, where dyeing is done before printing. Image A shows the fabric after dyeing, while Image B shows the fabric after dyeing and then digitally printing.

[0024] Figure 2 This is a printed fabric diagram of Embodiment 1 of the present invention.

[0025] Figure 3 These are comparative fabric diagrams of Embodiment 1 and Comparative Example 1 of the present invention; wherein Figure A is the fabric of Embodiment 1, and Figure B is the fabric of Comparative Example 1. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0027] Example 1: A method for preparing fabrics for digital printing by simultaneously sizing and dyeing the substrate includes the following steps: A. Pre-treat the semi-bleached cotton fabric, arrange it according to the pattern requirements, and keep the fabric surface flat by straightening the weft and stretching the fabric to obtain product A. B. Sizing and dyeing treatment in the same bath: Immerse product A in sizing dyeing solution. The composition of sizing dyeing solution includes: 30g / L of alkali-resistant double reactive dye, 60g / L of urea, 25g / L of sodium bicarbonate, 4g / L of anti-dyeing salt S and 25g / L of sodium alginate paste to obtain product B. C. Digitally print product B and treat it at low temperature to obtain product C; the printing ink is commercially available, for example, by weight, the components of the printing ink include: 10 parts N-methyl-2-pyrrolidone, 10 parts glycerol, 5 parts diethylene glycol, 15 parts vinyl sulfone / monochlorotriazine iso-reactive dye, 1 part pH buffer, trace additives, and the balance is water; the low temperature treatment is at 80℃ for 1 min.

[0028] D. Fix product C by steaming at 102℃ for 10 minutes to covalently bond the dye with the fiber, then wash and finish to obtain the finished product.

[0029] Finished fabrics such as Figure 2 As shown, the base color is uniform, without color spots, and the color fastness is grade 4. It saves 35% of water and reduces energy consumption by 30%.

[0030] Comparative Example 1: This comparative example is basically the same as Example 1, except that: The composition of the sizing dyeing solution includes 15 g / L baking soda, 60 g / L urea, 4 g / L anti-dyeing salt S, and 8 g / L sodium alginate.

[0031] The finished products of Example 1 and Comparative Example 1 were compared, and the comparison figures are shown below. Figure 3 As shown, A is the fabric of Example 1, and B is the fabric of Comparative Example 1. It can be seen that the base color and pattern of the fabric of Comparative Example 1 are very light, the fabric is uneven, and there are patterns. If mass production is carried out, the phenomenon of unstable color and color difference between the edge and the center will occur.

[0032] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for preparing fabrics in which digital printing sizing and dyeing are performed in the same bath, characterized in that: Includes the following steps: A. Pre-treat the semi-bleached fabric to obtain product A; B. Sizing and dyeing treatment in the same bath: Immerse product A in sizing dyeing solution. The composition of sizing dyeing solution includes: 5-50g / L of reactive dye, 30-100g / L of urea, 20-30g / L of sodium bicarbonate, 2-8g / L of anti-dyeing salt and 10-35g / L of sodium alginate to obtain product B. C. Digitally print product B and treat it at low temperature to obtain product C; D. Steam product C to fix its color, and obtain the finished product.

2. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: The fabric used in step A is pure cotton, linen, regenerated cellulose, or blended fiber fabric.

3. The fabric preparation method for digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: The reactive dye used in step B is an alkali-resistant dual-reactive dye.

4. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: In step B, the urea concentration is 50-80 g / L, and the baking soda concentration is 22-28 g / L.

5. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: The low-temperature treatment in step C is 60-100℃, and the treatment time is ≤3min.

6. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: The printing ink used in step C of digital printing is a reactive dye with dual reactive groups.

7. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: The printing ink in step C, by weight, comprises: 5-15 parts of cosolvent, 10-25 parts of humectant, 5-20 parts of reactive dye with dual reactive groups, and 0.5-2 parts of pH buffer.

8. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 7, characterized in that: The co-solvent used in step C is N-methyl-2-pyrrolidone.

9. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 7, characterized in that: The moisturizer used in step C is glycerin and / or diethylene glycol.

10. The method for preparing fabric by digital printing sizing and dyeing in the same bath according to claim 1, characterized in that: Step D specifically involves steaming product C at 100-103℃ for 8-12 minutes to fix the color, thus obtaining the finished product.

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