Reactive anti-reducing agent for active ink and preparation method of reactive anti-reducing agent

Abstract

The invention belongs to the field of chemical engineering, and particularly provides a reactive anti-reducing agent (reactive anti-reducing agent for active ink), the structural formula of the reactive anti-reducing agent is # imgabs0, and the molecular structure of the reactive anti-reducing agent simultaneously contains a nitro-aromatic structure with an anti-reducing effect, a sulfonic acid water-soluble group and a monochlorotriazine reactive group. The invention also provides a preparation method of the reactive anti-reducing agent. The reactive anti-reducing agent provided by the invention can form covalent bond combination with cotton fibers, inhibits the photoreduction reaction of dyes on the cotton fibers, and achieves the effect of persistently improving the color fastness to light for cotton fabrics dyed by reactive dyes.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a reactive anti-reducing agent and a preparation method thereof. Background Art

[0002] Cotton fabrics have excellent moisture absorption and breathability, and are often used for underwear and in special environments that are hot and humid. In order to increase the added value of cotton fabric products, cotton fabrics need to be dyed and finished. Reactive dyes are currently commonly used cotton dyes in printing and dyeing factories because of their advantages such as complete color spectrum, bright colors, low cost, and excellent fastness. For cotton fabrics dyed with reactive dyes, the dyes on the fabrics are prone to fading when used outdoors. The main reason for fading is that after the textiles are exposed to ultraviolet rays and visible light in the high-energy zone of sunlight, the dye structure changes, resulting in poor light fastness. The fading of textiles not only affects the appearance and performance of the product, but the dye photodegradation products may also have an impact on human health.

[0003] According to research, the photofading mechanism of dyes is related to the light source, dye structure and dye fiber type. Among them, medium-wave ultraviolet rays (UVB) and long-wave ultraviolet rays (UVA) have longer wavelengths and can penetrate the atmosphere to reach the earth's surface along with the visible light in sunlight. Fabrics are exposed to ultraviolet rays for a long time, which will cause photodegradation of dyes and damage the application performance of products.

[0004] From the dye structure point of view, the red reactive dye matrix is ​​mostly azo structure, and H acid (1-amino-8-naphthol-3,6-disulfonic acid) is the most common coupling intermediate in the azo structure. The light fastness of a series of red reactive dyes synthesized with H acid is lower than that of the other two primary colors (yellow and blue) reactive dyes. This is because when the diazo component and H acid undergo coupling reaction, the electron cloud on the electron-donating group of H acid (the diazo component is connected to the amino group under acidic conditions, and the amino group donates electrons; the diazo component is connected to the hydroxyl group under alkaline conditions, and the hydroxyl group donates electrons) moves toward the N=N direction, increasing the electron cloud density of N=N, causing N=N to easily undergo photochemical reactions when exposed to light, which ultimately manifests as low light fastness of red dyes containing H acid.

[0005] Light fastness refers to the color durability of dyed textiles when exposed to sunlight, and is one of the important indicators for evaluating the quality of dyed cotton fabric products. The higher the light fastness of dyed cotton fabrics, the greater the added value of the product. For example, the commonly used dye for digital printing red reactive ink is CI Reactive Red 24:1, which has good water solubility and excellent soap fastness. However, the light fastness of CI Reactive Red 24:1 on cotton fabrics is only level 3 to 4, and the dye is prone to fading and discoloration under light conditions, causing the application performance of dyed and printed textiles to deteriorate. Effectively improving the light fastness of dyes is the focus of the entire textile printing and dyeing industry. The textile industry has tried to use anti-reducing agents that resist photoreduction to perform light stabilization modification on dyed cotton fabrics, intending to improve light fastness from the perspective of reducing the photoreduction reaction of dyes in cotton fabrics, but the effect was found to be limited. Therefore, it is an urgent need for the printing and dyeing industry to develop a reactive anti-reducing agent that can be dissolved in water and form a lasting protection with cotton fibers, and effectively improve light fastness.

[0006] The currently available anti-reducing agent that can resist photoreduction is: dichloro-s-triazine anti-reducing agent A developed by Zhang Haiyan et al., which has a slow reaction rate and a long reaction time (6 hours). Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a reactive anti-reducing agent and a preparation method thereof.

[0008] In order to solve the above technical problems, the present invention provides a reactive anti-reducing agent (reactive anti-reducing agent for active ink), the structural formula of which is:

[0009]

[0010] The reactive anti-reduction agent of the present invention has a molecular structure containing a nitro aromatic hydrocarbon structure with an anti-reduction effect, a sulfonic acid water-soluble group and a monochloro-s-triazine reactive group.

[0011] The present invention also provides a method for preparing the reactive anti-reducing agent, comprising the following steps:

[0012] 1) A Friedel-Crafts acylation reaction is carried out between cyanuric chloride and m-aminobenzenesulfonic acid to obtain a reaction solution containing an intermediate (M1);

[0013] The intermediate (M1) is:

[0014]

[0015] 2) The reaction solution containing the intermediate (M1) undergoes Friedel-Crafts acylation reaction with m-nitroaniline to obtain a reactive anti-reducing agent (R2).

[0016] As an improvement of the preparation method of the reactive anti-reducing agent of the present invention:

[0017] The step 1) is:

[0018] Adding ice cubes to cyanuric chloride for slurrying to obtain slurry; dissolving m-aminobenzenesulfonic acid in deionized water to obtain m-aminobenzenesulfonic acid aqueous solution;

[0019] According to the molar ratio of cyanuric chloride to m-aminobenzenesulfonic acid = 1-1.01:1; adding m-aminobenzenesulfonic acid aqueous solution to the slurry, adjusting the pH to 5-6 (using sodium hydroxide as an acid binding agent), reacting at a reaction temperature of 0-5°C for 20-40 minutes to obtain a reaction solution containing the intermediate (M1);

[0020] Note: Use Ehrlich reagent to detect the end point of the reaction; after the reaction is completed, a condensation intermediate of m-aminobenzenesulfonic acid and cyanuric chloride is obtained;

[0021] The step 2) is:

[0022] Add m-nitroaniline to the reaction solution containing the intermediate (M1) obtained in step 1), adjust the pH to 6-7 (using sodium hydroxide as an acid-binding agent), and react at 40-45° C. for 5.5-6.5 hours, with a molar ratio of m-nitroaniline to cyanuric chloride of 1:1-1.01;

[0023] The obtained reaction solution is subjected to post-treatment to obtain a reactive anti-reducing agent (R2).

[0024] Note: Use Ehrlich reagent to detect the reaction endpoint.

[0025] As a further improvement of the preparation method of the reactive anti-reducing agent of the present invention, in step 1):

[0026] The weight ratio of cyanuric chloride to ice is 1:25-30, and the beating time is 20-40 minutes;

[0027] The amount of deionized water used is sufficient to dissolve the m-aminobenzenesulfonic acid.

[0028] As a further improvement of the preparation method of the reactive anti-reducing agent of the present invention, the post-treatment in step 2) is: acid precipitation and filtration of the obtained reaction liquid, and vacuum drying of the obtained filter cake to obtain the reactive anti-reducing agent (R2).

[0029] The reaction equation of the present invention is shown in Formula 1.

[0030]

[0031] Formula 1, Synthesis route of reactive anti-reducing agent

[0032] In the present invention, the nitroaromatic structure with anti-reduction effect can absorb superoxide anions, reduce the activation of ultraviolet rays in sunlight on the dye, and thus inhibit the photoreduction reaction of the dye; the sulfonic acid water-soluble group can enable the anti-reduction agent to be used together with the reactive dyes that are also water-soluble in the water system for dyeing and finishing of cotton fabrics; the role of the reactive group (monochloro-s-triazine) is to make the anti-reduction agent and the cotton fabric bonded together through covalent bonding, thereby increasing the wash resistance of the anti-reduction agent.

[0033] The present invention introduces sodium sulfonate water-soluble groups, nitro aromatic structures with anti-reduction effects and monochlorotriazine reactive groups into aromatic structures at the same time, thereby giving the anti-reduction agent good water solubility and reactivity with cotton fiber hydroxyl groups. When applied to cotton fabrics, the anti-reduction agent can be finished by water bath method and form a strong covalent bond with the cotton fibers. The nitro group can absorb superoxide anions, reduce the influence of photoreduction reaction on dyes, and thus simultaneously improve the light fastness of reactive dye-dyed cotton fabrics.

[0034] In summary, the reactive anti-reducing agent described in the present invention can form a covalent bond with cotton fibers, inhibit the occurrence of dye photoreduction reaction on cotton fibers, and achieve a durable light fastness improvement effect on cotton fabrics dyed with reactive dyes. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0036] Figure 1 This is the finishing process curve of dyed cotton fabric with reactive anti-reducing agent. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0038] Example 1: A method for preparing a reactive anti-reducing agent, comprising the following steps:

[0039] (1) In an ice bath, add an appropriate amount of crushed ice (about 50 g) and 1.84 g (0.1 mol) of cyanuric chloride to a 250 mL three-necked flask, and stir for 30 to 40 minutes with a mechanical stirrer to obtain a slurry.

[0040] Dissolve 1.75 g (0.1 mol) of m-aminobenzenesulfonic acid in an appropriate amount of deionized water to obtain an aqueous solution of m-aminobenzenesulfonic acid; the amount of deionized water used is only sufficient to ensure that the m-aminobenzenesulfonic acid is dissolved.

[0041] The aqueous solution of m-aminobenzenesulfonic acid is added to the slurry for Friedel-Crafts acylation reaction. During the reaction, sodium hydroxide solution is used as an acid-binding agent, the pH is kept at 5-6, the reaction temperature is 0-5°C, and the reaction time is about half an hour. The end point of the reaction is detected by using Ehrlich reagent (when the reagent shows on the filter paper that the yellow color becomes lighter and lighter until it is colorless, it is determined that the reaction has reached the end point). After the reaction is completed, the obtained reaction solution contains a condensed intermediate of m-aminobenzenesulfonic acid and cyanuric chloride (hereinafter referred to as intermediate M1).

[0042]

[0043] (2) Add 1.38 g (0.1 mol) of m-nitroaniline to the reaction solution containing the intermediate M1 obtained in step (1); adjust the pH of the reaction to 6-7 with sodium hydroxide solution, heat the reaction system in an oil bath to 40-45° C., and react for about 6 hours. Use Ehrlich reagent to detect the end point of the reaction.

[0044] After the reaction is completed, acid precipitation (add 20 ml of 36% hydrochloric acid), suction filtration, and vacuum drying (vacuum drying at 0°C to constant weight) are performed to obtain about 3.92 g (0.0092 mol) of reactive anti-reducing agent R2, with a yield of 93%.

[0045] The reactive anti-reducing agent R2 has the following structural formula:

[0046]

[0047] 1 H NMR (400MHz, DMSO-d6) δ10.69 (s, 2H), 10.44 (s, 1H), 8.03 (dd, J = 9.2Hz, 2H), 7.88 (d, J=8.2Hz, 4H), 7.65 (s, 1H), 7.48 (d, J=7.6Hz, 1H). ESIMS (m / z, 100%): 421.098 [MH]-.

[0048] The following experiment illustrates the application of the reactive anti-reducing agent R2 of the present invention on dyed cotton fabrics.

[0049] Experiment 1: CI Reactive Red 24:1 was selected for printing on cotton fabrics, and the printing and dyeing experiment was carried out according to the following process formula.

[0050] Dyeing and printing process

[0051] Printing and dyeing paste:

[0052] Take the preparation of 100g paste as an example: add 3g sodium bicarbonate, 3g anhydrous sodium sulfate, 8g urea and 83mL water into a 250mL three-necked flask, and stir vigorously with a mechanical stirrer to dissolve all the above drugs in the water. Finally, add 3g sodium alginate into the three-necked flask and stir for 4h for later use.

[0053] Dye paste:

[0054] First, prepare CI Reactive Red 24:1 dye solution, measure 5 mL of water, and then weigh 0.25 g of CI Reactive Red 24:1 and dissolve it in it. Then weigh 20 g of the prepared paste, use a 2 mL pipette to draw 2 mL of CI Reactive Red 24:1 dye solution and drop it into the paste, and use a mechanical stirrer to stir evenly.

[0055] Printing and dyeing process:

[0056] The prepared dye paste was printed on a 10×20 cm cotton fabric using a magnetic printing machine, and dried (80°C for 60 minutes). Then steamed at 100°C for 12 minutes; washed twice, followed by soaping (soap solution formula: 0.2 g anhydrous sodium carbonate, 100 mL water, 0.2 g sodium dodecylbenzene sulfonate, soaping temperature 90°C, soaping time 30 minutes), and drying (80°C for 60 minutes) to obtain CI Reactive Red 24:1 dyed cotton fabric.

[0057] Experiment 2: R2 obtained in the present invention was applied to the finishing of cotton fabric dyed with CI Reactive Red 24:1 obtained in Experiment 1, and the fading rate and light fastness of the dyed fabric were evaluated.

[0058] 1. Just a single soap wash:

[0059] 1) The post-finishing process is as follows:

[0060] Finishing process formula: R2 dosage is 1%, 2%, 3% (owf), anhydrous sodium sulfate (Na2SO4) is 30g / L, anhydrous sodium carbonate (Na2CO3) is 10g / L, and the bath ratio is 1:30. The finishing process curve is Figure 1 . Specifically:

[0061] 1) Set up the following three experimental groups:

[0062] At room temperature, R2 aqueous solution was added to the CI Reactive Red 24:1 dyed cotton fabric obtained in Experiment 1, and the dosage of R2 was 1%, 2%, and 3% (owf), respectively;

[0063] Bath ratio 1:30.

[0064] 2) While stirring, heat to 90°C at a rate of 2 min / °C, add anhydrous sodium sulfate (Na2SO4) to a concentration of 30 g / L, stir and react for 30 minutes, then add anhydrous sodium carbonate (Na2CO3) to a concentration of 10 g / L, stir and react for 30 minutes.

[0065] 3) Then cool to room temperature, wash with water, soap wash (soap wash in 95℃ water bath for 10min, the formula of soap wash liquid is 2g / L soap flakes, 2g / L anhydrous sodium carbonate), wash with water at room temperature again, and finally dry (dry at 80℃ for 60 minutes).

[0066] 2) Expose the R2 treated dyed cotton fabric and the untreated dyed cotton fabric (blank, i.e., the CI Reactive Red 24:1 dyed cotton fabric obtained in Experiment 1) under a 35W xenon lamp light source for 20h or 44h, with the light source 50cm away from the fabric surface;

[0067] Then, the K / S before and after exposure was measured according to GB / T 8427-2019 "Textiles - Tests for Color Fastness to Artificial Light: Xenon Arc Light" to obtain the light-induced fading rate F a The results are shown in Tables 1 and 2 below.

[0068] Table 1. Light-induced fading rate of dyed cotton fabric after R2 finishing and unfinished dyed cotton fabric (blank) after xenon lamp exposure for 20 hours

[0069]

[0070] As can be seen from Table 1, the light-induced fading rates of dyed cotton fabrics treated with R2 after 20 hours of xenon lamp exposure were reduced by 6.09%, 7.90% and 3.47% respectively. The difference in light-induced fading rates between the dyed cotton fabric treated with 2% (owf) R2 and the untreated dyed cotton fabric was the smallest.

[0071] Table 2. Light-induced fading rate of dyed cotton fabrics after R2 treatment and untreated dyed cotton fabrics exposed to xenon lamp for 44 hours

[0072]

[0073] The light fading rate Fa of dyed cotton fabrics after R2 finishing was reduced by 15.10%, 19.13% and 14.52% respectively after 44 hours of xenon lamp exposure. At 2% (owf), the light fading rate Fa of dyed cotton fabrics after R2 finishing was reduced the most after 44 hours of xenon lamp exposure, indicating that R2 has the best anti-light reduction effect at this dosage.

[0074] 2. Change "single soap wash" in "a" to "soap wash ten times", that is, the fabric obtained in step 3) above is repeatedly subjected to 9 times of soap wash - room temperature water washing - drying;

[0075] Then, the color fastness to light was tested in accordance with GB / T 8427-2019 “Textiles - Tests for Color Fastness - Artificial Light: Xenon Arc Light”; the results are shown in Table 3 below.

[0076] Table 3. Color fastness to light of dyed cotton fabrics after R2 finishing and unfinished dyed cotton fabrics after xenon lamp exposure

[0077]

[0078] After multiple soap washing, the light fastness grades of the fabric before and after soap washing are not much different, indicating that the cotton fabric dyed with CI Reactive Red 24:1 after R2 finishing has water resistance. When exposed to xenon lamp for 20 hours, the light fastness of the dyed cotton fabric after 1% (owf) R2 finishing is increased by about 1 grade compared with the blank control of CI Reactive Red 24:1 dyed cotton fabric; the light fastness of the dyed cotton fabric after 2% (owf) R2 finishing is increased by about 1.5 grades compared with the blank control of CI Reactive Red 24:1 dyed cotton fabric; the light fastness of the dyed cotton fabric after 3% (owf) R2 finishing is increased by about 0.5 grade compared with the blank control of CI Reactive Red 24:1 dyed cotton fabric.

[0079] When exposed to xenon lamp for 44 hours, the light fastness of the dyed cotton fabrics treated with 1% (owf) and 3% (owf) R2 increased by about 0.5 level compared with the blank control of CI Reactive Red 24:1 dyed cotton fabric; the light fastness of the dyed cotton fabrics treated with 2% (owf) R2 increased by about 1 level compared with the blank control of CI Reactive Red 24:1 dyed cotton fabric.

[0080] In summary, the R2 structure has a weak oxidation function and has a good effect in improving light fastness.

[0081] Comparative Example 1-1: The "m-nitroaniline" in Example 1 was replaced with "p-nitroaniline", the molar amount remained unchanged, and the rest was the same as Example 1.

[0082] The structural formula of the reactive anti-reducing agent is:

[0083]

[0084] Comparative Example 1-2: The "m-nitroaniline" in Example 1 is replaced by "o-nitroaniline", the molar amount remains unchanged, and the rest is the same as Example 1.

[0085] The structural formula of the reactive anti-reducing agent is:

[0086]

[0087] Comparative Example 2-1: The "m-aminobenzenesulfonic acid" in Example 1 is replaced by "p-aminobenzenesulfonic acid", the molar amount remains unchanged, and the rest is the same as Example 1.

[0088] The structural formula of the reactive anti-reducing agent is:

[0089]

[0090] Comparative Example 2-2: The "m-aminobenzenesulfonic acid" in Example 1 is replaced with "o-aminobenzenesulfonic acid", the molar amount remains unchanged, and the rest is the same as Example 1.

[0091] The structural formula of the reactive anti-reducing agent is:

[0092]

[0093] The reactive anti-reducing agents obtained in the above four comparative examples were subjected to corresponding experiments according to the above Experiments 1 and 2, with 2% (owf) finishing and dyeing of cotton fabrics by xenon lamp exposure for 44 hours. The results are shown in Tables 4 and 5:

[0094] Table 4. Light-induced fading rate of dyed cotton fabrics after finishing and unfinished dyed cotton fabrics exposed to xenon lamp for 44 hours

[0095]

[0096] Table 5. Color fastness to light corresponding to xenon lamp exposure for 44 hours

[0097] Soap once Soap ten times Comparative Example 1-1 3～4 3 Comparative Example 1-2 3～4 3 Comparative Example 2-1 3～4 3 Comparative Example 2-2 3～4 3

[0098] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. Reactive anti-reducing agent, characterized in that The structural formula is:

2. The method for preparing the reactive anti-reducing agent according to claim 1, characterized in that The steps include: 1) A Friedel-Crafts acylation reaction is carried out between cyanuric chloride and m-aminobenzenesulfonic acid to obtain a reaction solution containing an intermediate; The intermediate is: 2) The reaction solution containing the intermediate undergoes Friedel-Crafts acylation reaction with m-nitroaniline to obtain a reactive anti-reducing agent.

3. The method for preparing the reactive anti-reducing agent according to claim 2, characterized in that: The step 1) is: Adding ice cubes to cyanuric chloride for slurrying to obtain slurry; dissolving m-aminobenzenesulfonic acid in deionized water to obtain m-aminobenzenesulfonic acid aqueous solution; According to the molar ratio of cyanuric chloride to m-aminobenzenesulfonic acid = 1 to 1.01:1; adding the m-aminobenzenesulfonic acid aqueous solution to the slurry, adjusting the pH to 5 to 6, and reacting at a reaction temperature of 0 to 5° C. for 20 to 40 minutes to obtain a reaction solution containing an intermediate; The step 2) is: Add m-nitroaniline to the reaction solution containing the intermediate obtained in step 1), adjust the pH to 6-7, and react at 40-45° C. for 5.5-6.5 hours, with a molar ratio of m-nitroaniline to cyanuric chloride of 1:1-1.01; The obtained reaction solution is subjected to post-treatment to obtain a reactive anti-reducing agent.

4. The method for preparing the reactive anti-reducing agent according to claim 3, characterized in that In the step 1): Cyanuric chloride: ice cube = 1:25-30 weight ratio, beating time is 20-40 minutes; The amount of deionized water used is sufficient to dissolve the m-aminobenzenesulfonic acid.

5. The method for preparing the reactive anti-reducing agent according to claim 3 or 4, characterized in that The post-treatment in step 2) is as follows: acid precipitation and filtration of the obtained reaction solution, and vacuum drying of the obtained filter cake to obtain a reactive anti-reducing agent.

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