Reactive anti-reducing agent for reactive ink and method for preparing the same

Abstract

The application belongs to the field of chemical industry, and particularly provides a reactive anti-reducing agent (reactive anti-reducing agent for reactive ink), which has a structural formula. The reactive anti-reducing agent has a molecular structure containing a nitro aromatic structure with an anti-reducing effect, a water-soluble sulfonic acid group, and a monochloro-s-triazine reactive group. The application also provides a preparation method of the reactive anti-reducing agent. The reactive anti-reducing agent can form a covalent bond with cotton fibers, inhibit the occurrence of a light reduction reaction of dyes on the cotton fibers, and achieve a persistent light fastness improvement effect on reactive dyeing cotton fabrics.

Description

TECHNICAL FIELD

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

[0002] Cotton fabric has excellent moisture absorption and air permeability, and is often used for close-fitting clothes and special environments with heat and humidity. In order to improve the added value of cotton fabric products, the cotton fabric needs to be dyed and finished. Reactive dyes are commonly used in cotton dyeing plants at present due to their advantages of complete color spectrum, bright color, low cost, excellent fastness, etc. For cotton fabric dyed with reactive dyes, the dye on the fabric is prone to fading when used outdoors. The main reason for fading is that the structure of the dye changes after the textile is irradiated by ultraviolet light and visible light in the high-energy region of sunlight, resulting in poor light fastness. The fading of the textile not only affects the appearance and use performance of the product, but also may affect human health due to the photodegradation products of the dye.

[0003] According to research, the mechanism of light-induced fading of dyes is related to light source, dye structure and type of dyed fibers. Among them, the medium wave ultraviolet (UVB) and long wave ultraviolet (UVA) have longer wavelengths, which can penetrate the atmosphere to reach the earth's surface with visible light in sunlight. The fabric is subjected to long-term irradiation of ultraviolet light, which causes the photodegradation of the dye and damages the application performance of the product.

[0004] From the structure of the dye, the red reactive dye parent body is mostly azo structure, and H acid (1-amino-8-naphthol-3, 6-disulfonic acid) is the most common coupling intermediate in azo structure. A series of red reactive dyes synthesized from H acid have lower light fastness than other two primary colors (yellow and blue) reactive dyes. This is because when the diazonium component couples with H acid, the electron cloud on the electron-donating group of H acid (under acidic conditions, the diazonium component is connected next to the amino group, and the amino group donates electrons; under alkaline conditions, the diazonium component is connected next to the hydroxyl group, and the hydroxyl group donates electrons) moves to the N=N direction, increasing the electron cloud density of N=N, causing N=N to be susceptible to photochemical reaction when irradiated by light, and ultimately resulting in lower light fastness of red dyes containing H acid.

[0005] Light fastness refers to the color durability of dyed textile 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 fabric, the greater the added value of the product. For example, the commonly used dye for red reactive ink in digital printing is C.I. Reactive Red 24:1, which has good water solubility and excellent soaping fastness. However, the light fastness of C.I. Reactive Red 24:1 on cotton fabric is only 3-4 levels, and the dye can easily fade under light conditions, causing the application performance of dyed and printed textiles to deteriorate. Effectively improving the light fastness of the dye is the focus of the entire textile printing and dyeing industry. The textile industry has attempted to use anti-reducing agents that resist photoreduction to modify the light stability of dyed cotton fabric, with the intention of improving light fastness by reducing the photoreduction of dyes in cotton fabric. However, the results show that the effect is 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 durable protective layer with cotton fibers, and effectively improve the light fastness.

[0006] The existing anti-reducing agent with resistance to photoreduction is dichlorotriazine anti-reducing agent A developed by Zhang Haiyan et al., which has a slow reaction rate and requires a long reaction time (6 hours). SUMMARY

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

[0008] To solve the above technical problems, the present application provides a reactive anti-reducing agent (reactive anti-reducing agent for reactive ink), whose structural formula is:

[0009]

[0010] The reactive anti-reducing agent of the present application has a molecular structure containing a nitroarene structure with anti-reducing effect, a water-soluble sulfonic acid group, and a monochlorotriazine reactive group.

[0011] The present application also provides a preparation method of the above-mentioned reactive anti-reducing agent, comprising the following steps:

[0012] 1) Cyanoformyl chloride undergoes a Friedel-Crafts acylation reaction with m-aminobenzenesulfonic acid to obtain a reaction solution containing intermediate (M1);

[0013] The intermediate (M1) is:

[0014]

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

[0016] Improvement of the preparation method of the reactive anti-reducing agent of the present application:

[0017] The step 1) is:

[0018] Ice cubes are added to cyanuric chloride for beating, to obtain a slurry; m-aminobenzenesulfonic acid is dissolved in deionized water to obtain a m-aminobenzenesulfonic acid aqueous solution;

[0019] According to the molar ratio of cyanuric chloride:m-aminobenzenesulfonic acid = 1-1.01:1; the m-aminobenzenesulfonic acid aqueous solution is added to the slurry, the pH is adjusted to 5-6 (sodium hydroxide is used as the acid-binding agent), and the reaction is carried out at a reaction temperature of 0-5℃ for 20-40 minutes, to obtain a reaction liquid containing the intermediate (M1);

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

[0021] The step 2) is:

[0022] The m-nitroaniline is added to the reaction liquid containing the intermediate (M1) obtained in step 1), the pH is adjusted to 6-7 (sodium hydroxide is used as the acid-binding agent), and the reaction is carried out at 40-45℃ for 5.5-6.5 hours, with the molar ratio of m-nitroaniline:cyanuric chloride = 1:1-1.01;

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

[0024] Note: Ehrlich reagent is used to detect the reaction end point.

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

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

[0027] The amount of deionized water is ensured to be able to dissolve the m-aminobenzenesulfonic acid.

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

[0029] The reaction equation of the present application is shown in formula 1.

[0030]

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

[0032] In the present invention, the nitroaromatic structure with anti-reduction effect can absorb superoxide anions, reduce the activation of the dye by ultraviolet rays in sunlight, 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 dye that is 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 integrate the anti-reduction agent and the cotton fabric through covalent bonding, thereby increasing the wash resistance of the anti-reduction agent.

[0033] By simultaneously introducing a sodium sulfonate water-soluble group, a nitroarene structure with anti-reduction properties, and a monochloro-s-triazine reactive group into the aromatic hydrocarbon structure, the present invention imparts good water solubility and reactivity with the hydroxyl groups of cotton fibers to the anti-reduction agent. When applied to cotton fabrics, the anti-reduction agent can be finished in a waterbath and form a strong covalent bond with the cotton fibers. The nitro group can absorb superoxide anions, reducing the effects of photoreduction reactions on dyes, thereby simultaneously improving 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 lasting light fastness improvement effect on cotton fabrics dyed with reactive dyes. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The specific embodiments 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 with reference to 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) Add an appropriate amount of crushed ice (about 50 g) to a 250 mL three-necked flask under ice bath conditions, add 1.84 g (0.1 mol) of cyanuric chloride, and stir under a mechanical stirrer for 30 to 40 minutes 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 m-aminobenzenesulfonic acid solution is added to the slurry for the Friedel-Crafts acylation reaction. During the reaction, sodium hydroxide solution is used as the 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. Ehrlich reagent is used to detect the reaction end point (when the reagent shows yellow color becoming lighter and lighter until colorless on filter paper, the reaction is determined to reach the end point). After the reaction is completed, the obtained reaction solution contains m-aminobenzenesulfonic acid and a mononuclear intermediate (intermediate M1 for short) of cyanuric chloride.

[0042]

[0043] (2) 1.38 g (0.1 mol) of m-nitroaniline is added to the reaction solution containing intermediate M1 obtained in step (1); sodium hydroxide solution is used to keep the pH at 6-7 during the reaction, and the reaction system is heated to 40-45°C in an oil bath, and the reaction time is about 6 h. Ehrlich reagent is used to detect the reaction end point.

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

[0045] The structure of the reactive anti-reducing agent R2 is as follows:

[0046]

[0047] 1 H NMR (400 MHz, DMSO-d6) δ 10.69 (s, 2H), 10.44 (s, 1H), 8.03 (dd, J = 9.2 Hz, 2H), 7.88 (d, J = 8.2 Hz, 4H), 7.65 (s, 1H), 7.48 (d, J = 7.6 Hz, 1H). ESIMS (m / z, 100%) : 421.098 [M-H]-.

[0048] The application of the reactive anti-reducing agent R2 of the present application on dyed cotton fabric is illustrated by experiments as follows.

[0049] Experiment 1, C.I. Reactive Red 24:1 is selected to print cotton fabric, and printing and dyeing experiments are carried out according to the following process formula.

[0050] Dye printing and dyeing process

[0051] Printing and dyeing paste:

[0052] Example 1: Preparation of paste (100 g) : In a 250 mL three necked flask, 3 g of sodium bicarbonate, 3 g of anhydrous sodium sulfate, 8 g of urea and 83 mL of water were added. The mixture was stirred vigorously using a mechanical stirrer until all the chemicals were dissolved in water. Finally, 3 g of sodium alginate was added to the flask and stirred for 4 h to obtain the paste.

[0053] Dye paste:

[0054] First, a C.I. Reactive Red 24:1 dye solution was prepared. 5 mL of water was measured and 0.25 g of C.I. Reactive Red 24:1 was added to the water. Then, 20 g of the prepared paste was weighed and 2 mL of the C.I. Reactive Red 24:1 dye solution was added to the paste using a 2 mL pipette. The mixture was stirred using a mechanical stirrer until it was homogeneous.

[0055] Printing process:

[0056] The prepared dye paste was printed on 10 x 20 cm cotton fabric using a magnetic printing machine. The printed fabric was dried (at 80 °C for 60 min) and then steamed at 100 °C for 12 min. The fabric was washed twice and then soaped (soap formulation: 0.2 g of anhydrous sodium carbonate, 100 mL of water, and 0.2 g of sodium dodecyl benzene sulfonate; soaping temperature: 90 °C; soaping time: 30 min). The fabric was dried (at 80 °C for 60 min) to obtain C.I. Reactive Red 24:1 dyed cotton fabric.

[0057] Experiment 2: The R2 obtained in the present application was applied to the C.I. Reactive Red 24:1 dyed cotton fabric obtained in Experiment 1 for finishing, and the color fading rate and light fastness of the dyed fabric were evaluated.

[0058] I. Single soaping:

[0059] I) The finishing process was as follows:

[0060] Finishing process formulation: R2 was used at 1%, 2%, and 3% (o.w.f), anhydrous sodium sulfate (Na2SO4) was 30 g / L, and anhydrous sodium carbonate (Na2CO3) was 10 g / L. The bath ratio was 1:30. The finishing process curve was Figure 1 . Specifically:

[0061] 1) The following three experimental groups were set up:

[0062] R2 was added to the C.I. Reactive Red 24:1 dyed cotton fabric obtained in Experiment 1 at room temperature. The amount of R2 used was 1%, 2%, and 3% (o.w.f), respectively.

[0063] The bath ratio was 1:30.

[0064] 2) Under stirring, increase the temperature to 90℃ at a rate of 2min / ℃, add anhydrous sodium sulfate (Na2SO4) to a concentration of 30g / L, and keep stirring for 30min, then add anhydrous sodium carbonate (Na2CO3) to a concentration of 10g / L, and keep stirring for 30min.

[0065] 3) Then, cool to room temperature, wash with water, soapy wash (soapy wash for 10min in a water bath at 95℃, the soapy wash solution is composed of soap chips 2g / L and anhydrous sodium carbonate 2g / L), then wash with water at room temperature, and finally dry (dry at 80℃ for 60min).

[0066] II) The dyed cotton fabric after R2 finishing and the dyed cotton fabric without finishing (blank, i.e., the dyed cotton fabric of C.I. Reactive Red 24:1 obtained in Experiment 1) are exposed to 35W xenon lamp light source for 20h or 44h, and the light source is 50cm away from the surface of the fabric;

[0067] Then, the K / S before and after exposure is determined according to GB / T 8427—2019 Textiles—Color Fastness to Artificial Light—Xenon Arc, so as to obtain the photobleaching rate F a The results are shown in Table 1 and Table 2.

[0068] Table 1, photobleaching rate of dyed cotton fabric after R2 finishing and dyed cotton fabric without finishing (blank) exposed to xenon lamp for 20h

[0069]

[0070] As can be seen from Table 1, the photobleaching rate of the dyed cotton fabric after R2 finishing exposed to xenon lamp for 20h is reduced by 6.09%, 7.90% and 3.47% respectively. The difference between the photobleaching rate of the dyed cotton fabric after R2 finishing at 2% (o.w.f) and the dyed cotton fabric without finishing is the smallest.

[0071] Table 2, photobleaching rate of dyed cotton fabric after R2 finishing and dyed cotton fabric without finishing exposed to xenon lamp for 44h

[0072]

[0073] The photobleaching rate Fa of the dyed cotton fabric after R2 finishing exposed to xenon lamp for 44h is reduced by 15.10%, 19.13% and 14.52% respectively. At 2% (o.w.f), the photobleaching rate Fa of the dyed cotton fabric after R2 finishing exposed to xenon lamp for 44h is reduced the most, indicating that the effect of resisting photoreduction is the best at this dosage of R2.

[0074] II) Change the "single soapy wash" in "one" to "ten soapy washes", i.e., the fabric obtained in step 3) above is subjected to 9 more soapy washes--washing with water at room temperature--drying;

[0075] And then according to GB / T 8427—2019 "Textiles - Colour fastness tests - Colour fastness to artificial light: Xenon arc" to detect the light fastness; the results are shown in Table 3 below.

[0076] Table 3, Xenon lamp after the light fastness of R2 finished dyeing cotton fabric and unfinished dyeing cotton fabric

[0077]

[0078] After multiple soaping, the light fastness grade of the fabric before and after soaping has little difference, indicating that the C.I. Reactive Red 24:1 dyed cotton fabric after R2 finishing has water resistance. After 20h xenon lamp exposure, the light fastness of the C.I. Reactive Red 24:1 dyed cotton fabric after 1% (o.w.f) R2 finishing increases by about 1 grade compared with the blank control; the light fastness of the C.I. Reactive Red 24:1 dyed cotton fabric after 2% (o.w.f) R2 finishing increases by about 1.5 grade compared with the blank control; the light fastness of the C.I. Reactive Red 24:1 dyed cotton fabric after 3% (o.w.f) R2 finishing increases by about 0.5 grade compared with the blank control.

[0079] After 44h xenon lamp exposure, the light fastness of the C.I. Reactive Red 24:1 dyed cotton fabric after 1% (o.w.f), 3% (o.w.f) R2 finishing increases by about 0.5 grade compared with the blank control; the light fastness of the C.I. Reactive Red 24:1 dyed cotton fabric after 2% (o.w.f) R2 finishing increases by about 1 grade compared with the blank control.

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

[0081] Comparative Example 1-1, change "m-nitroaniline" in Example 1 to "p-nitroaniline", keep the same molar amount, and the rest is the same as Example 1.

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

[0083]

[0084] Comparative Example 1-2, change "m-nitroaniline" in Example 1 to "o-nitroaniline", keep the same molar amount, 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, change "m-aminobenzenesulfonic acid" in Example 1 to "p-aminobenzenesulfonic acid", keep the molar amount 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, change "m-aminobenzenesulfonic acid" in Example 1 to "o-aminobenzenesulfonic acid", keep the molar amount 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 the corresponding experiments of 2% (o.w.f) on the finished dyeing cotton fabric xenon lamp exposure for 44h according to the above Experiment 1 and Experiment 2, and the results are as follows in Table 4 and Table 5:

[0094] Table 4, light-induced color fading rate of finished dyeing cotton fabric and un-finished dyeing cotton fabric xenon lamp exposure for 44h

[0095]

[0096] Table 5, corresponding light fastness grade of xenon lamp exposure for 44h

[0097] One soaping Ten soapings 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 enumeration is only a few specific embodiments of the present application. Obviously, the present application is not limited to the above embodiments, but can also have many variations. All variations that can be derived or inferred by those of ordinary skill in the art from the disclosure of the present application should be considered as falling within the scope of protection of the present application.

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, wherein 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 a 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, wherein: The step 1) is: Adding ice cubes to cyanuric chloride and beating the mixture to obtain a slurry; dissolving m-aminobenzenesulfonic acid in deionized water to obtain a m-aminobenzenesulfonic acid aqueous solution; According to the molar ratio of cyanuric chloride to m-aminobenzenesulfonic acid = 1-1.01:1; adding the m-aminobenzenesulfonic acid aqueous solution to the slurry, adjusting the pH to 5-6, and reacting at a reaction temperature of 0-5°C for 20-40 minutes to obtain a reaction solution containing the 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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