Modified bentonite paste for active dye printing of cotton fabric, and preparation method and application thereof

Abstract

This invention relates to modified bentonite paste for reactive dye printing on cotton fabrics, its preparation method, and its applications. The modified bentonite paste of this invention is prepared by the following method: First, bentonite is reacted with dextrin to obtain a dextrin / bentonite modifier; then, polyethylene glycol is reacted with 2-chloroethyldiethylamine, and acidified with hydrochloric acid to obtain a polyethylene glycol-containing cationic modified ammonium salt; finally, the dextrin / bentonite modifier is mixed and reacted with the polyethylene glycol-containing cationic modified ammonium salt to obtain modified bentonite. The modified bentonite paste prepared by this invention, when used for reactive dye printing on cotton fabrics, produces printed fabrics with a desizing rate higher than 93%; good softness; high outline clarity; penetration rate higher than 87%; and high fastness to dry rubbing and washing, demonstrating excellent application prospects.

Description

Technical Field

[0001] This invention belongs to the field of paste preparation and application technology, specifically relating to modified bentonite paste for reactive dye printing on cotton fabrics, its preparation method and application. Background Technology

[0002] Printing paste is a high-molecular-weight compound that acts as a thickener and dye transfer agent in textile printing pastes. It is soluble in water or swells and disperses fully in water to form a thick colloidal solution. As an essential component of printing pastes, its rheological properties, water-holding capacity, reactivity with reactive dyes, and ease of washing directly affect the printing effect, such as the color of the printed fabric, the amount of color applied to the surface, the clarity of the pattern outline, the uniformity of printing, and the hand feel.

[0003] Reactive dye printing is currently the most common printing process for cellulosic fiber fabrics, and sodium alginate is mostly used as the printing paste. With the development of printing technology, the increasing requirements for the paste, and the rising price of sodium alginate, people are prompting the search for and research of alternatives to sodium alginate.

[0004] Bentonite is a type of clay rock, also known as montmorillonite clay rock. It is generally white or pale yellow, and can range in size from loose and soil-like to dense and hard. Its main chemical components are silicon dioxide, aluminum oxide, and water, and it also contains elements such as iron, magnesium, calcium, sodium, and potassium. The content of Na₂O and CaO significantly affects the physicochemical properties and processing performance of bentonite. Bentonite has strong hygroscopic and swelling properties, capable of absorbing 8 to 15 times its own volume of water, expanding in volume by several to 30 times. In aqueous media, it can disperse into gel-like and suspension states, and this solution exhibits certain viscosity, thixotropy, and lubricity. Bentonite is suspended in water and forms a paste when there is little water. These properties of bentonite make it suitable for use as a printing paste.

[0005] While bentonite possesses the potential to be used as a printing paste, its direct application in reactive dye printing still faces several drawbacks. Firstly, bentonite is difficult to paste; secondly, it cannot uniformly disperse chemical auxiliaries in a colloidal system; thirdly, its viscosity changes significantly upon dilution; and finally, bentonite has poor dye molecule transfer capabilities. These unfavorable factors limit the application of bentonite in printing pastes, necessitating technological breakthroughs to overcome these limitations. Summary of the Invention

[0006] In view of the above-mentioned drawbacks of the prior art, the purpose of this invention is to provide a modified bentonite paste for reactive dye printing on cotton fabrics, its preparation method and application.

[0007] The purpose of this invention is to provide a modified bentonite paste for reactive dye printing on cotton fabrics. The paste is prepared by the following method: First, bentonite is reacted with dextrin to obtain a dextrin / bentonite modifier; then, polyethylene glycol is reacted with 2-chloroethyldiethylamine and acidified with hydrochloric acid to obtain a polyethylene glycol-containing cationic modified ammonium salt; finally, the dextrin / bentonite modifier is mixed and reacted with the polyethylene glycol-containing cationic modified ammonium salt to obtain modified bentonite.

[0008] The purpose of this invention is to provide a method for preparing modified bentonite paste for reactive dye printing on cotton fabrics, the specific method comprising the following steps:

[0009] (1) Reaction of dextrin and bentonite: Dissolve dextrin and bentonite separately in distilled water and disperse them by ultrasonication for 2-4 hours to obtain dextrin aqueous solution and bentonite aqueous solution; mix the dextrin aqueous solution and bentonite aqueous solution at 60-70℃ and stir at constant temperature for 2-4 hours to obtain dextrin / bentonite modified aqueous solution.

[0010] Preferably, the ratio of dextrin (g) to distilled water (mL) in the dextrin aqueous solution is 1:10-12; the ratio of bentonite (g) to distilled water (mL) in the bentonite aqueous solution is 1:10-12; and the volume ratio of the dextrin aqueous solution to the bentonite aqueous solution is 1:3-5.

[0011] (2) Preparation of polyethylene glycol cationic modified ammonium salt: Dissolve polyethylene glycol in distilled water, adjust the pH of the solution to 10-11, add 2-chloroethyldiethylamine, adjust the reaction temperature to 40-50℃, and the reaction time to 3-5 hours; after the reaction, neutralize with 2-4wt% hydrochloric acid aqueous solution to pH 5-7 to obtain an aqueous solution containing polyethylene glycol cationic modified ammonium salt.

[0012] Preferably, the ratio of polyethylene glycol (g), distilled water (mL), and 2-chloroethyldiethylamine (g) is 1:10-12:0.1-0.3; the molecular weight of the polyethylene glycol is any one of 500, 1000, or 2000.

[0013] (3) Mixing reaction: At 60℃, the aqueous solution of yellow dextrin / bentonite modified material obtained in step (1) and the aqueous solution of polyethylene glycol cationic modified ammonium salt obtained in step (2) are mixed. The pH value of the solution is adjusted to 3-5 with 2-4 wt% hydrochloric acid aqueous solution. The reaction is stirred for 3-5 hours. After the reaction is completed, the pH value of the solution is adjusted to 6-7 with 20-30 wt% NaOH aqueous solution. The modified bentonite is obtained by spray drying.

[0014] Preferably, the ratio of the aqueous solution of dextrin / bentonite modified material obtained in step (1) to the aqueous solution of polyethylene glycol cationic modified ammonium salt obtained in step (2) is 1:0.2-0.4.

[0015] Another object of the present invention is to provide an application of modified bentonite paste for reactive dye printing on cotton fabrics. The application method is as follows: weigh the dyeing agents according to the color paste formula, dissolve the reactive dye, urea and anti-dye salt S in distilled water, mix them evenly to dissolve them; finally add the modified bentonite paste, stir evenly to obtain a color paste for reactive dye printing on cotton fabrics; print the obtained color paste on cotton fabrics.

[0016] Preferably, the pigment paste formulation is as follows: 20-24g of modified bentonite paste prepared according to the present invention; 3-5g of reactive dye; 10-14g of urea; 2-2.4g of anti-dyeing salt S; and water to 100g.

[0017] Preferably, the reactive dye is any one of Reactive Red P-2B, Reactive Turquoise Blue K-GP, and Reactive Brilliant Red K-2BP.

[0018] Preferably, the printing process is as follows: flat screen printing (scraping once) → drying (100℃, 3min) → steaming (102℃, 10min) → rinsing twice with cold water → soaping → washing with cold water → drying.

[0019] The present invention has the following significant advantages:

[0020] (1) This invention uses bentonite as raw material and takes advantage of its montmorillonite layered structure and its ability to swell and disperse in water into colloidal particles. It then uses ion exchange technology to insert an organic covering agent to produce modified bentonite.

[0021] (2) This invention modifies bentonite into a high-value cotton fabric reactive dye printing paste, which significantly improves the application value of bentonite.

[0022] (3) The organic modified clay paste prepared by the present invention is used for reactive dye printing on cotton fabrics. The printed fabrics produced have the advantages of a desizing rate of more than 93%, good softness, high outline clarity, penetration rate of more than 87%, and high fastness to dry rubbing and fastness to soaping. It has a good application prospect.

[0023] (4) The inventors of this application unexpectedly discovered that by combining bentonite with yellow dextrin, its plasticity is increased, which is beneficial to its paste formation; and by inserting long polyethylene glycol branches into the lamellar structure, its wettability of fabrics is increased, which is beneficial to the transfer of dye molecules. Detailed Implementation

[0024] The present invention is described in detail below with reference to the embodiments and comparative examples.

[0025] Main raw material sources: Reactive dye Reactive Red P-2B and anti-dyeing salt S were purchased from Zhejiang Runtu Co., Ltd.

[0026] Example 1

[0027] The preparation method of modified bentonite paste for reactive dye printing on cotton fabrics includes the following steps:

[0028] (1) Reaction of dextrin with bentonite: 10g of dextrin and 10g of bentonite were dissolved in 110mL of distilled water and ultrasonically dispersed for 3 hours to obtain dextrin aqueous solution and bentonite aqueous solution; at 65℃, 25mL of dextrin aqueous solution and 100mL of bentonite aqueous solution were mixed and stirred at a constant temperature for 3 hours to obtain dextrin / bentonite modified aqueous solution.

[0029] (2) Preparation of polyethylene glycol cationic modified ammonium salt: 10g of polyethylene glycol with a molecular weight of 1000 was dissolved in 110mL of distilled water, the pH of the solution was adjusted to 10.5, 2g of 2-chloroethyldiethylamine was added, the reaction temperature was adjusted to 45℃, and the reaction time was 4 hours. After the reaction was completed, the pH was neutralized to 6 with 3wt% hydrochloric acid aqueous solution to obtain an aqueous solution containing polyethylene glycol cationic modified ammonium salt.

[0030] (3) Mixing reaction: At 60℃, 100mL of the yellow dextrin / bentonite modified aqueous solution obtained in step (1) and 30mL of the polyethylene glycol cationic modified ammonium salt aqueous solution obtained in step (2) were mixed. The pH of the solution was adjusted to 4 with 3wt% hydrochloric acid aqueous solution. The reaction was stirred for 4 hours. After the reaction was completed, the pH of the solution was adjusted to 6.5 with 25wt% NaOH aqueous solution. The modified bentonite was obtained by spray drying.

[0031] Another object of the present invention is to provide an application of modified bentonite paste for reactive dye printing on cotton fabrics. The application method is as follows: The color paste formula is selected as follows: 22g of modified bentonite paste prepared according to the present invention; 4g of reactive dye; 12g of urea; 2.2g of anti-dye salt S; water is added to 100g; the dyes and chemicals are weighed according to the color paste formula; the reactive dye Reactive Blue K-GP, urea, and anti-dye salt S are dissolved in distilled water and mixed evenly until dissolved; finally, the modified bentonite paste is added and stirred evenly to obtain a color paste for reactive dye printing on cotton fabrics; the obtained color paste is then printed on cotton fabrics. The printing process is as follows: flat screen printing (scraping once) → drying (100℃, 3min) → steaming (102℃, 10min) → rinsing twice with cold water → soaping → washing with cold water → drying.

[0032] Example 2

[0033] The preparation method of modified bentonite paste for reactive dye printing on cotton fabrics includes the following steps:

[0034] (1) Reaction of dextrin with bentonite: 10g of dextrin and 10g of bentonite were dissolved in 100mL of distilled water and ultrasonically dispersed for 2 hours to obtain dextrin aqueous solution and bentonite aqueous solution; at 60℃, 25mL of dextrin aqueous solution and 75mL of bentonite aqueous solution were mixed and stirred at a constant temperature for 2 hours to obtain dextrin / bentonite modified aqueous solution.

[0035] (2) Preparation of polyethylene glycol cationic modified ammonium salt: 10g of polyethylene glycol with a molecular weight of 500 was dissolved in 100mL of distilled water, the pH of the solution was adjusted to 10, 1g of 2-chloroethyldiethylamine was added, the reaction temperature was adjusted to 40℃, and the reaction time was 3 hours. After the reaction was completed, the pH was neutralized to 5 with 2wt% hydrochloric acid aqueous solution to obtain an aqueous solution containing polyethylene glycol cationic modified ammonium salt.

[0036] (3) Mixing reaction: At 60℃, 100mL of the yellow dextrin / bentonite modified aqueous solution obtained in step (1) and 20mL of the polyethylene glycol cationic modified ammonium salt aqueous solution obtained in step (2) were mixed. The pH of the solution was adjusted to 3 with 2wt% hydrochloric acid aqueous solution. The reaction was stirred for 3 hours. After the reaction was completed, the pH of the solution was adjusted to 6 with 20wt% NaOH aqueous solution. The modified bentonite was obtained by spray drying.

[0037] Another object of the present invention is to provide an application of modified bentonite paste for reactive dye printing on cotton fabrics. The application method is as follows: The color paste formula is selected as follows: 20g of modified bentonite paste prepared according to the present invention; 3g of reactive dye; 10g of urea; 2.0g of anti-dye salt S; water is added to 100g; the dyes and chemicals are weighed according to the color paste formula; the reactive dye Reactive Blue K-GP, urea, and anti-dye salt S are dissolved in distilled water and mixed evenly until dissolved; finally, the modified bentonite paste is added and stirred evenly to obtain a color paste for reactive dye printing on cotton fabrics; the obtained color paste is then printed on cotton fabrics. The printing process is as follows: flat screen printing (scraping once) → drying (100℃, 3min) → steaming (102℃, 10min) → rinsing twice with cold water → soaping → washing with cold water → drying.

[0038] Example 3

[0039] The preparation method of modified bentonite paste for reactive dye printing on cotton fabrics includes the following steps:

[0040] (1) Reaction of dextrin with bentonite: 10g of dextrin and 10g of bentonite were dissolved in 120mL of distilled water and ultrasonically dispersed for 4 hours to obtain dextrin aqueous solution and bentonite aqueous solution; at 70℃, 25mL of dextrin aqueous solution and 125mL of bentonite aqueous solution were mixed and stirred at a constant temperature for 4 hours to obtain dextrin / bentonite modified aqueous solution.

[0041] (2) Preparation of polyethylene glycol cationic modified ammonium salt: 10g of polyethylene glycol with a molecular weight of 2000 was dissolved in 120mL of distilled water, the pH of the solution was adjusted to 11, 3g of 2-chloroethyldiethylamine was added, the reaction temperature was adjusted to 50℃, and the reaction time was 5 hours. After the reaction was completed, the pH was neutralized to 7 with 4wt% hydrochloric acid aqueous solution to obtain an aqueous solution containing polyethylene glycol cationic modified ammonium salt.

[0042] (3) Mixing reaction: At 60℃, 100mL of the yellow dextrin / bentonite modified aqueous solution obtained in step (1) and 40mL of the polyethylene glycol cationic modified ammonium salt aqueous solution obtained in step (2) were mixed. The pH of the solution was adjusted to 5 with 4wt% hydrochloric acid aqueous solution. The reaction was stirred for 5 hours. After the reaction was completed, the pH of the solution was adjusted to 7 with 30wt% NaOH aqueous solution. The modified bentonite was obtained by spray drying.

[0043] Another object of the present invention is to provide an application of modified bentonite paste for reactive dye printing on cotton fabrics. The application method is as follows: The color paste formula is selected as follows: 24g of modified bentonite paste prepared according to the present invention; 5g of reactive dye; 14g of urea; 2.4g of anti-dye salt S; water is added to 100g; the dyes and chemicals are weighed according to the color paste formula; the reactive dye Reactive Blue K-GP, urea, and anti-dye salt S are dissolved in distilled water and mixed evenly until dissolved; finally, the modified bentonite paste is added and stirred evenly to obtain a color paste for reactive dye printing on cotton fabrics; the obtained color paste is then printed on cotton fabrics. The printing process is as follows: flat screen printing (scraping once) → drying (100℃, 3min) → steaming (102℃, 10min) → rinsing twice with cold water → soaping → washing with cold water → drying.

[0044] Comparative Example A

[0045] Compared with Example 1, the reaction between dextrin and bentonite in step (1) was not carried out. Specifically, 10g of bentonite was dissolved in 110mL of distilled water and ultrasonically dispersed for 3 hours to obtain a bentonite aqueous solution. The "dextrin / bentonite modified aqueous solution" in step (3) was replaced with "bentonite aqueous solution". Other preparation and application methods remained unchanged from Example 1.

[0046] Comparative Example B

[0047] Compared with Example 1, steps (2) and (3) were omitted, and the aqueous solution of yellow dextrin / bentonite modified material prepared in step (1) was directly used in the paste. The application method remained unchanged from Example 1.

[0048] Comparative Example C

[0049] Compared with Example 1, the amount of “the aqueous solution of polyethylene glycol cationic modified ammonium salt obtained in step (2)” in step (3) was reduced from “30 mL” to “3 mL”, while the other preparation and application methods remained unchanged from Example 1.

[0050] Comparative Example D

[0051] Compared with Example 1, the amount of “the aqueous solution of polyethylene glycol cationic modified ammonium salt obtained in step (2)” in step (3) was increased from “30 mL” to “300 mL”, while the other preparation and application methods remained unchanged from Example 1.

[0052] Comparative Example E

[0053] DNY textile printing paste (produced by Hubei Daya Biotechnology Co., Ltd.) from the procurement market was used as the paste in this embodiment. The color paste was prepared by the method of Example 1 and printed on cotton fabric.

[0054] Application performance testing:

[0055] The viscosity of the pastes prepared in Examples 1-3 and Comparative Example AE was tested using a digital viscometer. The printing viscosity index (PVI value) was calculated as follows: Among them, η6 and η 0.6 The values ​​represent the viscosity of the paste at 6 r / min and 0.6 r / min, respectively. The test results are shown in Table 1.

[0056] The printed cotton fabrics obtained from Examples 1-3 and Comparative Example AE were subjected to relevant tests: the K / S value was measured using a computer colorimeter; the penetration rate was expressed as the ratio of the K / S value on the reverse side to the K / S value on the front side of the fabric; the color fastness to washing was tested according to GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Washing"; the color fastness to dry rubbing was tested according to GB / T3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Rubbing"; the formula for calculating the desizing rate is: m1 represents the mass of the printed and dried fabric, m2 represents the mass of the printed fabric after washing, and m0 represents the mass of the unprinted fabric; Fabric softness test: The softness of the printed fabric was tested using a fabric style meter; Outline sharpness test: The sharpness level was assessed visually; The test results are shown in Table 1.

[0057] Table 1. Performance Evaluation of Modified Bentonite Paste for Reactive Dye Printing on Cotton Fabrics

[0058]

[0059]

[0060] As shown in Table 1, comparing Example 1 and Comparative Example A reveals that the reaction between dextrin and bentonite is beneficial to improving the printing performance of the modified bentonite paste. Comparing Example 1 and Comparative Example B reveals that the long-chain polyethylene glycol in the modified bentonite paste is beneficial to its printing performance. Comparing Example 1, Comparative Examples C and D reveals that grafting an appropriate amount of long-chain polyethylene glycol onto bentonite is beneficial to its printing performance. Comparing Examples 1-3 and Comparative Example E reveals that, compared with existing commercial printing pastes on the market, the modified bentonite paste prepared by this invention and the cotton fabrics printed with it meet or exceed the standards of existing commercial printing pastes and their printed cotton fabrics in many test indicators.

Claims

1. A method for preparing a modified bentonite paste for reactive dye printing on cotton fabrics, characterized in that, The preparation method includes the following steps: Reaction of dextrin with bentonite: Dissolve dextrin and bentonite separately in distilled water and ultrasonically disperse for 2-4 hours to obtain dextrin aqueous solution and bentonite aqueous solution; mix the dextrin aqueous solution and bentonite aqueous solution at 60-70℃ and stir at a constant temperature for 2-4 hours to obtain dextrin / bentonite modified aqueous solution. Preparation of polyethylene glycol cationic modified ammonium salt: Polyethylene glycol is dissolved in distilled water, the pH of the solution is adjusted to 10-11, 2-chloroethyldiethylamine is added, the reaction temperature is adjusted to 40-50℃, and the reaction time is 3-5 hours; after the reaction is completed, the pH is neutralized to 5-7 with 2-4 wt% hydrochloric acid aqueous solution to obtain an aqueous solution containing polyethylene glycol cationic modified ammonium salt; Mixing reaction: At 60 °C, the aqueous solution of yellow dextrin / bentonite modified material obtained in step (1) and the aqueous solution of cation-modified ammonium salt of polyethylene glycol obtained in step (2) were mixed. The pH of the solution was adjusted to 3-5 with 2-4 wt% hydrochloric acid aqueous solution. The reaction was stirred for 3-5 hours. After the reaction was completed, the pH of the solution was adjusted to 6-7 with 20-30 wt% NaOH aqueous solution. The solution was spray-dried to obtain modified bentonite paste. In step (2), the ratio of polyethylene glycol, distilled water and 2-chloroethyldiethylamine is 1g: (10-12)mL: (0.1-0.3)g; the molecular weight of polyethylene glycol is any one of 500, 1000 or 2000. In step (3), the ratio of the aqueous solution of dextrin / bentonite modified material obtained in step (1) to the aqueous solution of cation-modified ammonium salt of polyethylene glycol obtained in step (2) is 1: (0.2-0.4).

2. The method for preparing modified bentonite paste for reactive dye printing on cotton fabrics according to claim 1, characterized in that, In step (1), the ratio of dextrin to distilled water in the dextrin aqueous solution is 1g: (10-12)mL; the ratio of bentonite to distilled water in the bentonite aqueous solution is 1g: (10-12)mL; and the volume ratio of dextrin aqueous solution to bentonite aqueous solution is 1: (3-5).

3. A modified bentonite paste for reactive dye printing on cotton fabrics, characterized in that, It is prepared by the method for preparing modified bentonite paste for reactive dye printing on cotton fabrics as described in any one of claims 1 to 2.

4. The application of a modified bentonite paste for reactive dye printing on cotton fabrics as described in claim 3, characterized in that, The application method is as follows: weigh the dyeing and chemical materials according to the color paste formula, dissolve the reactive dye, urea and anti-dye salt S in distilled water, mix evenly to dissolve it; finally add the modified bentonite paste, stir evenly, and prepare the reactive dye printing color paste for cotton fabrics; print the prepared color paste on the cotton fabric.

5. The application of the modified bentonite paste for reactive dye printing on cotton fabrics according to claim 4, characterized in that, The pigment paste formulation is as follows: 20-24g of modified bentonite paste prepared in this invention; 3-5g of reactive dye; 10-14g of urea; 2-2.4g of anti-dyeing salt S; and water to 100g.

6. The application of the modified bentonite paste for reactive dye printing on cotton fabrics according to claim 4, characterized in that, The reactive dye is any one of Reactive Red P-2B, Reactive Turquoise Blue K-GP, and Reactive Brilliant Red K-2BP.

7. The application of the modified bentonite paste for reactive dye printing on cotton fabrics according to claim 4, characterized in that, The printing process is as follows: flat screen printing, squeegee printing once → drying at 100℃ for 3 minutes → steaming at 102℃ for 10 minutes → rinsing twice with cold water → soaping → washing with cold water → drying.

Images