Wool fabric control product with banned azo dye as well as preparation method and application of wool fabric control product

Abstract

The invention provides a banned azo dye wool fabric quality control product as well as a preparation method and application thereof. The synthetic azo dye is adopted to prepare the wool fabric standard quality control product capable of generating the determined 2-naphthylamine content through reduction. The uniformity and the stability of the prepared quality control product can meet the requirements of CNASGL03 < Proficiency Verification Sample Uniformity and Stability Evaluation Guideline >.

Description

Technical Field

[0001] This invention belongs to the field of textile testing technology, specifically relating to a quality control product for wool fabrics containing prohibited azo dyes, its preparation method, and its application. Background Technology

[0002] Azo dyes are organic dyes containing at least one azo group (-N=N-) and with one or more aromatic ring structures attached to both ends of the azo group. Because azo dyes have many advantages, such as a wide range of colors, strong tinting strength, bright and long-lasting colors, high color fastness, simple manufacturing, and low price, they have become a widely used class of synthetic dyes in the textile printing and dyeing process. However, some prohibited azo dyes, after prolonged contact with the human body, especially when the color fastness of the product is poor, can enter the body through the skin. Under the action of sweat and metabolism, these dyes can be reduced and decomposed to produce carcinogenic aromatic amines, posing a health hazard. Therefore, the detection of prohibited azo dyes has become one of the most important safety performance indicators in textile quality testing.

[0003] Currently, the detection of prohibited azo dyes in textiles primarily employs gas chromatography / mass spectrometry (GC / MS) and high-performance liquid chromatography (HPLC). Commonly used domestic and international standards include GB / T 17592-2024, EN14362-1:2012, and ISO 14362-1:2017. The detection principle of prohibited azo dyes involves immersing a certain amount of textiles in a buffer solution with pH=6.0. At a specific temperature, the dye on the textiles is reduced by a reducing agent, producing aromatic amines. The amines are then extracted, concentrated, and diluted to a suitable volume before being detected using a suitable method. However, the sample pretreatment steps are complex and time-consuming. Furthermore, the complexity of the textile sample matrix can lead to significant errors in the detection of prohibited azo dyes, resulting in false positives and large discrepancies in test results. This poses considerable challenges to the detection of prohibited azo dyes and can, in severe cases, cause disputes and economic losses.

[0004] To effectively identify laboratory risks, discover discrepancies in laboratory test results, improve laboratory testing capabilities, and ensure the accuracy of test results, this invention prepares a standard sample of purple wool fabric containing a banned azo dye that can be reduced to 2-naphthylamine. With the implementation of laws in various countries banning the use of banned azo dyes, these dyes are no longer sold on the market, posing significant challenges to the preparation of standard samples that can reduce and degrade aromatic amines. Summary of the Invention

[0005] This invention utilizes synthesized azo dyes to prepare standard quality control samples for wool fabrics that can be reduced to produce a definite 2-naphthylamine content. The prepared samples are homogeneous and stable, meeting the requirements of CNAS GL03, "Guideline for the Evaluation of Homogeneity and Stability of Proficiency Testing Samples." The azo dyes used in this invention can be used to prepare quality control samples with accurate content for the detection of decomposable 2-naphthylamine dyes in textiles.

[0006] One of the objectives of this invention is to provide a quality control product for wool fabrics that are prohibited from using azo dyes, which is a wool fabric obtained by dyeing with azo dyes shown in formula (I) and / or formula (II);

[0007]

[0008] Where R is H, Cl, or Br.

[0009] According to the present invention, the azo dyes represented by formula (I) and / or formula (II) are obtained by reacting 2-naphthylamine diazonium salt and 2-naphthol compounds. The azo dyes represented by formula (I) and / or formula (II) are prepared by the following steps:

[0010] Step (1) 2-Naphthylamine is diazotized by adding sodium nitrite dropwise under acidic conditions to obtain a 2-naphthylamine diazonium salt solution;

[0011] Step (2) The 2-naphthylamine diazonium salt solution obtained in step (1) and the 2-naphthol compound are coupled under alkaline conditions, and the azo dye is obtained after post-treatment.

[0012] According to an embodiment of the present invention, step (1) specifically includes: stirring the components including 2-naphthylamine, glacial acetic acid, and inorganic acid until homogeneous, and then adding sodium nitrite dropwise under stirring conditions to carry out a diazotization reaction to obtain a 2-naphthylamine diazonium salt solution; preferably,

[0013] The inorganic acid is selected from at least one of concentrated hydrochloric acid, hydrobromic acid, concentrated sulfuric acid, and phosphoric acid;

[0014] The molar ratio of glacial acetic acid to 2-naphthylamine is (1-10):1, for example, it can be any ratio among 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1 or any ratio within the range of any two of the above ratios. Preferably, the molar ratio of glacial acetic acid to 2-naphthylamine is (5-7):1.

[0015] The molar ratio of the inorganic acid to 2-naphthylamine is (2-8):1, for example, it can be any ratio among 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any ratio within the range of any two of the above ratios. Preferably, the molar ratio of the inorganic acid to 2-naphthylamine is (2.5-5.5):1.

[0016] The molar ratio of 2-naphthylamine to sodium nitrite is 1:(1-5), for example, it can be any ratio of 1:1, 1:2, 1:3, 1:4, 1:5 or any ratio within the range of any two of the above ratios. Preferably, the molar ratio of 2-naphthylamine to sodium nitrite is 1:(1-3).

[0017] The temperature of the diazotization reaction is -5 to 20°C, for example, it can be any temperature among -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 10, 20°C or any two of the above temperature ranges. Preferably, the temperature of the diazotization reaction is -5 to 5°C.

[0018] The diazotization reaction time is 0.5 to 4 hours, for example, it can be any time from 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 hours or any two of the above time ranges. Preferably, the diazotization reaction time is 1 to 1.5 hours.

[0019] According to an embodiment of the present invention, step (2) specifically includes: mixing a 2-naphthol compound and an alkaline aqueous solution in an ice-water bath, adding the 2-naphthylamine diazonium salt solution obtained in step (1), reacting under alkaline conditions, adjusting the product obtained after the reaction to acidic conditions and continuing the reaction, and obtaining the azo dye by filtration and purification; preferably,

[0020] The 2-naphthol compounds are selected from at least one of 2-naphthol, 3-chloro-2-naphthol, 4-chloro-2-naphthol, 5-chloro-2-naphthol, 6-chloro-2-naphthol, 7-chloro-2-naphthol, 8-chloro-2-naphthol, 3-bromo-2-naphthol, 4-bromo-2-naphthol, 5-bromo-2-naphthol, 6-bromo-2-naphthol, 7-bromo-2-naphthol, and 8-bromo-2-naphthol.

[0021] The alkaline compound in the alkaline aqueous solution is selected from at least one of alkali metal compounds and ammonia water, preferably at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia water;

[0022] In the alkaline aqueous solution, the concentration of the alkaline compound is 0.2 to 5 mol / L, for example, it can be any concentration from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5 mol / L or a concentration value between any two of the above concentration values. Preferably, the concentration of the alkaline compound is 0.5 to 1 mol / L.

[0023] The molar ratio of the 2-naphthol compound to the alkaline compound in the alkaline aqueous solution is 1:(1 to 10), for example, it can be any ratio among 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any ratio within the range of any two of the above ratios. Preferably, the molar ratio of the 2-naphthol compound to the alkaline compound in the alkaline aqueous solution is 1:(1 to 5).

[0024] The molar ratio of the 2-naphthol compound to the 2-naphthylamine diazonium salt is 1:(0.7-2.5), for example, it can be any ratio among 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:2, 1:2.5 or any ratio within the range of any two of the above ratios. Preferably, the molar ratio of the 2-naphthol compound to the 2-naphthylamine diazonium salt is 1:(0.8-1.5).

[0025] The reaction conditions under alkaline conditions are: pH 8-9, temperature 0-20℃, and time 0.5-4h; the alkaline conditions can be adjusted using commonly used alkaline compounds, such as at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia water.

[0026] The reaction conditions under the acidic conditions are: pH 5-6, temperature 15-20℃, and time 0.5-4h; the acidic conditions can be adjusted by commonly used acidic compounds, such as at least one of hydrochloric acid, hydrobromic acid, concentrated sulfuric acid, and phosphoric acid.

[0027] The second objective of this invention is to provide a method for preparing the above-mentioned quality control product of wool fabric with prohibited azo dyes, comprising: mixing dye, auxiliaries and water to obtain a dye liquor, immersing pre-wetted wool fabric in the liquor after a first heating, maintaining the temperature for dyeing after a second heating, and washing and drying after cooling to obtain the quality control product of wool fabric with prohibited azo dyes; wherein the dye comprises the azo dye shown in formula (I) and / or formula (II).

[0028] According to the present invention, in the method for preparing the quality control product of the wool fabric with banned azo dyes:

[0029] The auxiliary agent is selected from at least one of ammonium sulfate, sodium acetate, urea, and sodium alkyl sulfonate;

[0030] In the dyeing solution, the concentration of the auxiliary agent can be added according to the commonly used concentration, for example, the concentration of the auxiliary agent is 1-20 g / L;

[0031] In the dyeing solution, the concentration of the azo dye is calculated from the absorbance-concentration standard curve obtained by a UV-Vis spectrophotometer. Preferably, the concentration of the azo dye is 0.001–0.06 g / L. Specifically, the absorbance of the dyeing solution is first calculated from the quality control concentration and dyeing rate of 2-naphthylamine, and then the concentration of the azo dye in the dyeing solution is calculated from the absorbance-concentration standard curve.

[0032] According to an embodiment of the present invention, the absorbance-concentration standard curve can be plotted using common methods. For example, a series of dye solutions with different concentrations are prepared, and the corresponding absorbances are measured using a UV-Vis spectrophotometer. Then, a curve is plotted with concentration as the abscissa and absorbance as the ordinate. The resulting curve equation is y = ax + b (Equation 1), where y is the absorbance of the azo dye solution, x is the concentration of the azo dye (mg / kg), a is the slope of the curve, and b is the intercept. When calculating the concentration of the dye in the dye solution, the absorbance value at the 2-naphthylamine quality control concentration is substituted into Equation 1. The absorbance value at the 2-naphthylamine quality control concentration is calculated using Equation 2.

[0033]

[0034] In Equation 2, C 浓度 γ is the quality control concentration of 2-naphthylamine (mg / kg), γ is the calibration coefficient (γ is determined based on the dyeing rate and 2-naphthylamine quality control concentration in Table 1; when the 2-naphthylamine quality control concentration is at the end of the range, the calibration coefficient γ takes the lower value), and ρ is the areal density of the wool fabric (g / m³). 2 .

[0035] Table 1. List of parameters for azo dyes

[0036] absorbance Dyeing rate / % Calibration coefficient γ 2-Naphthylamine quality control concentration (mg / Kg) 0-0.5 90 0.93 0-35 0.5-0.7 85 1.12 40-60 0.7-0.9 80 1.26 60-80 0.9-1 75 1.31 80-100

[0037] According to the present invention, in the method for preparing the quality control product of the wool fabric with banned azo dyes:

[0038] The conditions for the first temperature increase are: increasing the temperature at a rate of 2-5℃ / min to 45-60℃;

[0039] The conditions for the second heating are: heating at a rate of 0.5–2 °C / min to 85–100 °C;

[0040] The conditions for heat preservation and dyeing are: heat preservation and dyeing at 85-100℃ for 30-180 minutes;

[0041] The cooling conditions are as follows: cooling to 20-50℃ at a rate of 2-5℃ / min.

[0042] The third objective of this invention is to use the above-mentioned quality control product for wool fabrics containing prohibited azo dyes or the above-mentioned preparation method to prepare textiles containing prohibited azo dyes.

[0043] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0044] 1. The azo dye preparation process provided by this invention is simple and the raw materials are readily available;

[0045] 2. The azo dye provided by this invention can accurately determine the dye concentration required for preparing 2-naphthylamine quality control products, thereby preparing quality control products that meet the requirements;

[0046] 3. The method for preparing quality control products provided by the present invention can prepare textile quality control products with excellent uniformity and stability. Attached Figure Description

[0047] Figure 1 The absorbance curve of the azo dye prepared in Example 1 is shown.

[0048] Figure 2 The stability curve of the azo dye prepared in Example 1 is shown.

[0049] Figure 3 The absorbance curve of the azo dye prepared in Example 2 is shown.

[0050] Figure 4 The stability curve of the azo dye prepared in Example 2 is shown. Detailed Implementation

[0051] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0052] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0053] Example 1

[0054] Synthesis of azo dyes:

[0055] 1. Diazotization reaction

[0056] Take 0.01 mol of 2-naphthylamine, 3.7 mL of glacial acetic acid, and 0.055 mol of concentrated hydrochloric acid, and add them to a 100 mL flask placed in an ice-water bath. Start stirring and maintain the reaction temperature at 0–5 °C. Immediately add 1 mL of 15 mol / L NaNO2 solution dropwise, and react for 1 h to obtain a mustard-yellow diazonium salt solution.

[0057]

[0058] 2. Coupling reaction

[0059] Take 0.01 mol 2-naphthol, 0.01 mol NaOH, and 15 mL of water, add them to a 250 mL container, place it in an ice-water bath, and start stirring. Slowly add the prepared diazonium salt solution (while stirring in the ice-water bath) dropwise into the container; at this point, the liquid in the container turns red. Control the pH of the reaction solution in the container to 8–9 by adding 0.5 mol / L NaOH solution. After reacting for 2 hours (stirring and placing in an ice-water bath), add concentrated hydrochloric acid dropwise at room temperature to adjust the pH to 5–6, and stir the reaction for 1 hour. After the reaction is complete, pour out the liquid from the three-necked flask and filter it. Purify the azo dye by crystallization.

[0060]

[0061] Preparation of quality control samples for wool fabrics containing prohibited azo dyes: Prepare a quality control fabric sample with a 2-naphthylamine concentration of 30 mg / kg.

[0062] (1) Select wool fabric:

[0063] To check if the woven wool fabric has a clean and flawless appearance, the weight is 200g / m². 2 .

[0064] (2) Pretreatment of raw fabric: Weigh about 600g of raw fabric and put it into soft water at a ratio of 1:5. Soak for 30 minutes, take out the completely wet raw fabric and wring out the water.

[0065] (3) Dye solution preparation:

[0066] The absorbance of the azo dye obtained in Example 1 at different dye concentrations (0.005 g / L, 0.01 g / L, 0.02 g / L, and 0.025 g / L) was measured at λ = 538 nm using a UV-Vis spectrophotometer. A working curve of dye absorbance was constructed with dye concentration on the x-axis and absorbance on the y-axis, as shown below. Figure 1 As shown, the standard curve equation is obtained as: y = 38.122x - 0.0009 (Equation 1), and the linear correlation is 0.9999.

[0067] The absorbance of the dye solution is calculated using Equation 2.

[0068]

[0069] In Equation 2, C 浓度 The value is 30 mg / kg, the dyeing rate is 0.9, the calibration coefficient γ is 0.93, and the areal density ρ of the wool fabric is 200 g / m². 2The absorbance of the dye solution was calculated to be 0.352; then, the concentration of azo dye in the dye solution was calculated to be 0.0092 g / L using Formula 1.

[0070] The azo dye, ammonium sulfate, and water prepared above were mixed to obtain a dye solution, wherein the concentration of the azo dye was 0.0092 g / L and the concentration of the ammonium sulfate was 2.5 g / L.

[0071] 4. Add dye liquor at a mass ratio of 1:30, heat to 50°C at room temperature at a rate of 2°C / min, put in the fully wetted wool fabric, heat to 100°C at a rate of 1°C / min, keep warm for dyeing for 60 minutes, and then cool to room temperature at a rate of 2°C / min.

[0072] 5. Wash with cold water until no more color comes off, wring dry, and dry in a baking machine.

[0073] 6. After dyeing and drying, remove 1-2 cm from both ends of the sample along the warp direction and 0.2-0.3 cm from both ends of the sample along the weft direction. Seal the remaining sample in a polyethylene self-sealing bag and store it at room temperature, in a dry place, away from light.

[0074] Test Example 1: Stability Study of Dye Solution

[0075] The absorbance of the azo dye prepared in Example 1 was measured at its maximum absorption wavelength using a UV-Vis spectrophotometer for six consecutive weeks to investigate the stability of the azo dye. The absorbance changes were as follows: Figure 2 As shown.

[0076] from Figure 2 As can be seen from the results, the absorbance of the azo dye prepared in Example 1 did not change after 6 weeks of storage, indicating that the dye has good stability and can be used to prepare quality control samples for the detection of banned azo dyes.

[0077] Test Example 2: Testing of 2-naphthylamine content in woolen fabrics treated with azo dyes.

[0078] The uniformity and stability of dyed fabrics were tested according to the national standard GB / T 17592-2011 "Determination of Banned Azo Dyes in Textiles". The method is as follows:

[0079] Sample preparation: Weigh 1.0 g of sample (prepared into 5 mm × 5 mm pieces), place in a capped glass tube, add citrate buffer solution, and react thoroughly by shaking in a constant temperature water bath. Then, reduce with sodium dithionate solution. Elute and extract with diethyl ether using a silica gel column, concentrate using a rotary evaporator, and analyze using gas chromatography-mass spectrometry after adjusting the volume. This method is a general method for the detection of azo dyes in textiles, has undergone long-term validation, and is also the main detection method used in proficiency testing activities.

[0080] Uniformity test

[0081] In accordance with the requirements of CNAS-GL003 "Guidelines for the Evaluation of Homogeneity and Stability of Proficiency Testing Samples", the prepared samples were numbered, and 10 samples were randomly selected for homogeneity testing. Each sample was tested twice under repeated conditions, for a total of 20 tests, which were conducted in random order. The detection results of 2-naphthylamine are shown in Table 2.

[0082] Table 2 Results of Sample Uniformity Test

[0083]

[0084] One-way ANOVA was used, and the results are shown in Table 3.

[0085] Table 3. Analysis of variance results of the test results

[0086]

[0087] As can be seen from the results in Table 3, F < F crit This indicates that the quality control sample prepared in Example 1 is homogeneous.

[0088] Stability test

[0089] After completing the homogeneity test of the samples, 2-naphthylamine was tested every 3 months. Six samples were taken each time, randomly selected according to the requirements of CNAS-GL003 "Guidelines for the Evaluation of Homogeneity and Stability of Proficiency Testing Samples". The stability of the samples was evaluated using a t-test, calculated as follows:

[0090]

[0091] Let be the average of n measurements, μ be the reference value (using the average value from the uniformity test, 30.72), and S be the standard deviation of the n measurements. If t is less than t0... 0.05(n-1) This indicates that there is no significant difference between the stability test results and the reference value, and the sample is stable. The test results are shown in Table 4.

[0092] Table 4. Sample stability test results

[0093]

[0094] In Table 4, t for both tests is less than t0. 0.05(n-1) =2.015, indicating that the sample has good stability over time.

[0095] In summary, using the azo dye synthesized in Example 1, the dye concentration required to accurately prepare 30 mg / kg of 2-naphthylamine quality control material can be calculated using the formula. Following the prescribed dyeing process, the prepared samples were subjected to uniformity and stability tests according to the national standard GB / T17592-2011 "Determination of Prohibited Azo Dyes in Textiles". The average concentration of the sample after 20 tests was 30.72 mg / kg, and the uniformity and stability met the requirements of NAS-GL003 "Guideline for Evaluation of Uniformity and Stability of Proficiency Testing Samples", making it suitable for 2-naphthylamine quality control.

[0096] Example 2

[0097] Synthesis of azo dyes:

[0098] 1. Diazotization reaction

[0099] Take 0.01 mol of 2-naphthylamine, 4.0 mL of glacial acetic acid, and 0.055 mol of concentrated hydrochloric acid, and add them to a 100 mL flask placed in an ice-water bath. Start stirring and maintain the reaction temperature at 0–5 °C. Immediately add 1 mL of 20 mol / L NaNO2 solution dropwise, and react for 1 h to obtain a mustard-yellow diazonium salt solution.

[0100]

[0101] 2. Coupling reaction

[0102] Take 0.01 mol 4-chloro-2-naphthol, 0.01 mol NaOH, and 15 mL of water, add them to a 250 mL container, place it in an ice-water bath, and start stirring. Slowly add the prepared diazonium salt solution (while stirring in the ice-water bath) dropwise into the container until the solution changes color. Control the pH of the reaction solution in the container at 8–9 by adding 0.5 mol / L NaOH solution. After reacting for 3 hours (stirring and placing in an ice-water bath), add concentrated hydrochloric acid dropwise at room temperature to adjust the pH to 5–6, and stir the reaction for 1.5 hours. After the reaction is complete, pour out the mixture in the container and filter it. Purify the azo dye by crystallization.

[0103]

[0104] Preparation of quality control samples for wool fabrics containing prohibited azo dyes: Prepare a quality control fabric sample with a 2-naphthylamine concentration of 60 mg / kg.

[0105] (1) Select wool fabric:

[0106] To check if the woven wool fabric has a clean and flawless appearance, the weight is 200g / m². 2 .

[0107] (2) Pretreatment of raw fabric: Weigh about 600g of raw fabric and put it into soft water at a ratio of 1:5. Soak for 30 minutes, take out the completely wet raw fabric and wring out the water.

[0108] (3) Dye solution preparation:

[0109] The absorbance of the azo dye obtained in Example 2 at different dye concentrations (0.005 g / L, 0.01 g / L, 0.02 g / L, and 0.025 g / L) was measured at λ = 538 nm using a UV-Vis spectrophotometer. A working curve of dye absorbance was constructed with dye concentration on the x-axis and absorbance on the y-axis, as shown below. Figure 3 As shown, the standard curve equation is obtained as y = 35.428x - 0.0215 (Equation 3), and the linear correlation is 0.9977.

[0110] The absorbance of the dye solution is calculated using Equation 2:

[0111]

[0112] In Equation 2, C 浓度 The value is 60 mg / kg, the dyeing rate is 0.85, the calibration coefficient γ is 1.12, and the areal density ρ of the wool fabric is 200 g / m². 2 The absorbance of the dye solution was calculated to be 0.620; then, the concentration of the azo dye in the dye solution was calculated to be 0.018 g / L by substituting it into Equation 3.

[0113] The azo dye, ammonium sulfate, and water prepared above were mixed to obtain a dye solution, wherein the concentration of the azo dye was 0.018 g / L and the concentration of the ammonium sulfate was 2.5 g / L.

[0114] 4. Add dye liquor at a mass ratio of 1:30, heat to 50°C at room temperature at a rate of 2°C / min, put in the fully wetted wool fabric, heat to 100°C at a rate of 1°C / min, keep warm for dyeing for 60 minutes, and then cool to room temperature at a rate of 2°C / min.

[0115] 5. Wash with cold water until no more color comes off, wring dry, and dry in a baking machine.

[0116] 6. After dyeing and drying, remove 1-2 cm from both ends of the sample along the warp direction and 0.2-0.3 cm from both ends of the sample along the weft direction. Seal the remaining sample in a polyethylene self-sealing bag and store it at room temperature, in a dry place, away from light.

[0117] Test Example 3: Stability Study of Dye Solution

[0118] The absorbance of the azo dye prepared in Example 2 was measured at its maximum absorption wavelength using a UV-Vis spectrophotometer for six consecutive weeks to investigate the stability of the azo dye. The changes in absorbance are shown below. Figure 4 As shown.

[0119] from Figure 4 As can be seen from the results, the absorbance of the azo dye prepared in Example 2 did not change after being stored for 6 weeks, indicating that the dye has good stability and can be used to prepare quality control samples for the detection of banned azo dyes.

[0120] Test Example 4: Testing of 2-naphthylamine content in woolen fabrics treated with azo dyes

[0121] The uniformity and stability of dyed fabrics were tested according to the national standard GB / T 17592-2011 "Determination of Banned Azo Dyes in Textiles". The method is as follows:

[0122] Sample preparation: Weigh 1.0 g of sample (prepared into 5 mm × 5 mm pieces), place in a capped glass tube, add citrate buffer solution, and react thoroughly by shaking in a constant temperature water bath. Then, reduce with sodium dithionate solution. Elute and extract with diethyl ether using a silica gel column, concentrate using a rotary evaporator, and analyze using gas chromatography-mass spectrometry after adjusting the volume. This method is a general method for the detection of azo dyes in textiles, has undergone long-term validation, and is also the main detection method used in proficiency testing activities.

[0123] Uniformity test

[0124] In accordance with the requirements of CNAS-GL003 "Guidelines for the Evaluation of Homogeneity and Stability of Proficiency Testing Samples", the prepared samples were numbered, and 10 samples were randomly selected for homogeneity testing. Each sample was tested twice under repeated conditions, for a total of 20 tests, which were conducted in random order. The detection results of 2-naphthylamine are shown in Table 5.

[0125] Table 5. Sample uniformity test results

[0126]

[0127] One-way ANOVA was used, and the results are shown in Table 6.

[0128] Table 6. Analysis of Variance Results of the Detection Results

[0129]

[0130] As can be seen from the results in Table 6, F < F crit This indicates that the quality control sample prepared in Example 2 is homogeneous.

[0131] Stability test

[0132] After completing the homogeneity test of the samples, the 2-naphthylamine content was tested every 3 months, with 6 samples taken each time. Following the requirements of CNAS-GL003 "Guidelines for the Evaluation of Homogeneity and Stability of Proficiency Testing Samples", 6 samples were randomly selected each time. The t-test was used to evaluate the stability of the samples, and the calculation formula is as follows:

[0133]

[0134] Let be the average of n measurements, μ be the reference value (using the average value from the uniformity test, 60.46), and S be the standard deviation of the n measurements. If t is less than t0... 0.05(n-1) This indicates that there was no significant difference between the stability test results and the reference value, and the sample is stable. The detection results of 2-naphthylamine are shown in Table 7.

[0135] Table 7. Sample stability test results

[0136]

[0137] In Table 7, t for both tests is less than t0. 0.05(n-1) =2.015, indicating that the sample has good stability over time.

[0138] In summary, using the azo dye synthesized in Example 2, the dye concentration required to accurately prepare 60 mg / kg of 2-naphthylamine quality control material can be calculated using the formula. Following the prescribed dyeing process, the prepared samples were subjected to uniformity and stability tests according to the national standard GB / T17592-2011 "Determination of Prohibited Azo Dyes in Textiles". The average concentration of the sample after 20 tests was 60.46 mg / kg, and the uniformity and stability met the requirements of NAS-GL003 "Guideline for Evaluation of Uniformity and Stability of Proficiency Testing Samples", making it suitable for 2-naphthylamine quality control.

Claims

1. A quality control product for wool fabrics with prohibited azo dyes, which is a wool fabric obtained by dyeing with azo dyes as shown in formula (I) and / or formula (II); in, R can be H, Cl, or Br.

2. The quality control product for wool fabrics with banned azo dyes according to claim 1, characterized in that, The azo dyes represented by formula (I) and / or formula (II) are obtained by reacting 2-naphthylamine diazonium salt and 2-naphthol compounds.

3. The quality control product for wool fabrics with banned azo dyes according to claim 2, characterized in that, The azo dyes represented by formula (I) and / or formula (II) are prepared by the following steps: Step (1) 2-Naphthylamine is diazotized by adding sodium nitrite dropwise under acidic conditions to obtain a 2-naphthylamine diazonium salt solution; Step (2) The 2-naphthylamine diazonium salt solution obtained in step (1) and the 2-naphthol compound are coupled under alkaline conditions, and the azo dye is obtained after post-treatment.

4. The quality control product for wool fabrics with banned azo dyes according to claim 3, characterized in that, Step (1) specifically includes: stirring the components containing 2-naphthylamine, glacial acetic acid, and inorganic acid until homogeneous, then adding sodium nitrite dropwise under stirring to carry out a diazotization reaction, thereby obtaining a 2-naphthylamine diazonium salt solution; preferably, The inorganic acid is selected from at least one of concentrated hydrochloric acid, hydrobromic acid, concentrated sulfuric acid, and phosphoric acid; and / or, The molar ratio of glacial acetic acid to 2-naphthylamine is (1-10):1, preferably (5-7):1; and / or, The molar ratio of the inorganic acid to 2-naphthylamine is (2-8):1, preferably (2.5-5.5):1; and / or, The molar ratio of 2-naphthylamine to sodium nitrite is 1:(1-5), preferably 1:(1-3); and / or, The diazotization reaction is performed at a temperature of -5 to 20°C, preferably -5 to 5°C; and / or, The diazotization reaction takes 0.5 to 4 hours, preferably 1 to 1.5 hours.

5. The quality control product for wool fabrics with banned azo dyes according to claim 3, characterized in that, Step (2) specifically includes: mixing 2-naphthol compounds and an alkaline aqueous solution in an ice-water bath, adding the 2-naphthylamine diazonium salt solution obtained in step (1), reacting under alkaline conditions, adjusting the product obtained after the reaction to acidic conditions and continuing the reaction, filtering and purifying to obtain the azo dye; preferably, The 2-naphthol compounds are selected from at least one of 2-naphthol, 3-chloro-2-naphthol, 4-chloro-2-naphthol, 5-chloro-2-naphthol, 6-chloro-2-naphthol, 7-chloro-2-naphthol, 8-chloro-2-naphthol, 3-bromo-2-naphthol, 4-bromo-2-naphthol, 5-bromo-2-naphthol, 6-bromo-2-naphthol, 7-bromo-2-naphthol, and 8-bromo-2-naphthol; and / or, The alkaline compound in the alkaline aqueous solution is selected from at least one of alkali metal compounds and ammonia water, preferably at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia water; and / or, In the alkaline aqueous solution, the concentration of the alkaline compound is 0.2–5 mol / L, preferably 0.5–1 mol / L; and / or, The molar ratio of the 2-naphthol compound to the alkaline compound in the alkaline aqueous solution is 1:(1-10), preferably 1:(1-5); and / or, The molar ratio of the 2-naphthol compound to the 2-naphthylamine diazonium salt is 1:(0.7–2.5), preferably 1:(0.8–1.5); and / or, The reaction conditions under alkaline conditions are: pH 8–9, temperature 0–20°C, and time 0.5–4 h; and / or, The reaction conditions under acidic conditions are: pH 5-6, temperature 15-20℃, and time 0.5-4h.

6. A method for preparing a quality control sample of wool fabric with banned azo dyes as described in any one of claims 1 to 5, comprising: A dye solution is obtained by mixing azo dye, auxiliaries and water. After the first heating, the pre-wetted wool fabric is placed in the solution. After the second heating, the solution is kept warm and dyed. After cooling, the solution is washed with water and dried to obtain the quality control product of the wool fabric containing the prohibited azo dye. The dyes therein include the azo dyes shown in formula (I) and / or formula (II).

7. The preparation method according to claim 6, characterized in that, The auxiliary agent is selected from at least one of ammonium sulfate, sodium acetate, urea, and sodium alkyl sulfonate; and / or, The concentration of the auxiliary agent in the dye solution is 1-20 g / L.

8. The preparation method according to claim 6, characterized in that, The concentration of the azo dye in the dyeing solution is calculated from the absorbance-concentration standard curve obtained by a UV-Vis spectrophotometer. Preferably, the concentration of the azo dye is 0.001 to 0.06 g / L.

9. The preparation method according to claim 6, characterized in that, The conditions for the first temperature increase are: increasing the temperature at a rate of 2–5 °C / min to 45–60 °C; and / or, The conditions for the second heating are: heating at a rate of 0.5–2 °C / min to 85–100 °C; and / or, The conditions for the heat-preserving staining are: heat preservation and staining at 85–100℃ for 30–180 min; and / or, The cooling conditions are as follows: cooling to 20-50℃ at a rate of 2-5℃ / min.

10. The quality control product of the prohibited azo dye wool fabric according to any one of claims 1 to 5 or the preparation method according to any one of claims 6 to 9, used to prepare textiles with prohibited azo dyes.

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