A kind of testing method of acid dye color fastness to water

Abstract

The invention discloses a test method for color fastness to water of acid dyes, comprising the following steps: 1) cutting at least two pieces of fabrics of equal mass of the same specification, wherein one piece of fabric adopts a standard dye, and the other fabrics adopt a dye to be tested, dyeing under the same conditions, and obtaining a standard dyed fabric and a dyed fabric to be tested after drying; the standard dye is a standard dye corresponding to the dye to be tested; 2) dissolving phosphate-free washing powder to obtain a phosphate-free washing powder solution; 3) immersing the standard dyed fabric and the dyed fabric to be tested in an equal amount of phosphate-free washing powder solution, stirring, and taking out after standing for a certain period of time; 4) taking the phosphate-free washing powder solution after soaking the standard dyed fabric and the dyed fabric to be tested in step 3), measuring its absorption intensity in the visible light range respectively, and comparing, and obtaining the test result of color fastness to water. The test method of the present invention can realize the quantitative test of color fastness to water, so as to obtain more accurate test results.

Description

Technical Field

[0001] The invention belongs to the technical field of textile dyeing detection, and in particular relates to a method for testing the water fastness of acid dyes. Background Art

[0002] Color fastness refers to the resistance of the color of textiles to various effects during processing and use. Among them, color fastness to water immersion is an important indicator for evaluating the color fastness of textiles in regular household washing. Color fastness to water immersion is affected by the properties of the fabric itself on the one hand, and is closely related to the quality of the dyes used for fabric dyeing on the other hand. However, there are currently no relevant test standards for color fastness to water immersion, resulting in the lack of a unified standard test method as a basis for various manufacturers. The test methods used by different companies are different. Therefore, it is difficult for dye manufacturers, downstream textile industries and end customers to form a consistent understanding of the quality of textile color fastness to water immersion.

[0003] On the other hand, most of the current testing methods use qualitative testing methods, drawing on the test methods of water fastness or soap fastness, and assessing the grade through human visual observation. This test method of assessing the grade by qualitative observation will cause differences in grade assessment due to factors such as different observers and different ambient light, which will lead to low accuracy of the test results of water fastness, causing disputes when conducting product quality appraisal.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for testing the color fastness of acid dyes to water immersion. The light absorption intensity of the aqueous solution obtained after the dyed fabric is soaked in water is measured to quantitatively characterize the color fastness to water immersion of the dyed fabric to be tested, thereby realizing the quantitative test of the color fastness to water immersion and improving the accuracy of the test results. At the same time, the test results are obtained by comparing the dye to be tested with the standard dye, which is conducive to unifying the test standards among different production enterprises.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] A method for testing the color fastness of acid dyes to water immersion, comprising the following steps:

[0008] 1) cutting at least two pieces of fabrics of the same specifications and of the same mass, wherein one piece of fabric is dyed with a standard dye and the other piece of fabric is dyed with a dye to be tested, dyeing them under the same conditions, and drying them to obtain a standard dyed fabric and a dyed fabric to be tested; the standard dye is a standard dye corresponding to the dye to be tested;

[0009] 2) dissolving the non-phosphorus washing powder to obtain a non-phosphorus washing powder solution;

[0010] 3) Immerse the standard dyed fabric and the dyed fabric to be tested in equal amounts of phosphorus-free detergent solution, stir, and take out after standing for a certain period of time;

[0011] 4) Taking the phosphorus-free washing powder solution after soaking the standard dyed fabric and the dyed fabric to be tested in step 3), respectively measuring the absorption intensity thereof in the visible light range, and comparing them to obtain the test result of the color fastness to water immersion.

[0012] In the above scheme, the standard dye is consistent with the type of dye to be tested, and the color fastness to water immersion has been generally recognized in the industry. Therefore, different types of dyes to be tested have different standard dyes. When testing the color fastness to water immersion, the corresponding standard dye is selected as a reference according to the type of dye to be tested.

[0013] In the test, the absorbance intensity of the water solution obtained after the dyed fabric is soaked in water is measured to quantitatively characterize the color fastness to water of the dyed fabric, thereby realizing the quantitative test of the color fastness to water, and improving the accuracy of the test results. At the same time, each time the test is performed, the standard dye is tested together with the dye to be tested, so that the standard dye and the dye to be tested are used to dye the fabric and subsequently process the fabric under exactly the same test conditions, and the absorbance intensity of the water solution obtained after the standard dyed fabric is soaked with the standard dye and the water solution obtained after the dyed fabric to be tested is soaked with the test dye are respectively measured and compared, and the absorption intensity value of the water solution obtained from the dyed fabric to be tested is not directly used, which eliminates the errors caused by different dyeing equipment, operators, experimental equipment and other uncontrollable environmental factors as much as possible, and is also conducive to unifying the test standards for color fastness to water among different production enterprises.

[0014] On the other hand, compared with the test method in the prior art of soaking the dyed fabric in water and then drying it for colorimetry, the above scheme directly measures the soaking water solution, eliminating the time for drying the dyed fabric after taking it out, thereby simplifying the test process, shortening the time required for testing, and helping to improve test efficiency.

[0015] Further, step 4) specifically includes the following steps:

[0016] 41) Take the non-phosphorus washing powder solution after soaking the standard dyed fabric and the non-phosphorus washing powder solution after soaking the dyed fabric to be tested, and use a UV-visible spectrophotometer to measure their absorption curves in the visible light range, and obtain the absorption curve C of the non-phosphorus washing powder solution after soaking the standard dyed fabric in the visible light range. 标准 , and the absorption curve C in the visible light range after the dyed fabric to be tested is soaked in the non-phosphorus washing powder solution 待测 ;

[0017] 42) Calculate the absorption curve C obtained in step 41) respectively 标准 and absorption curve C 待测 The integral value in the visible light range is used to obtain the visible light absorption intensity Integ after the standard dyed fabric is soaked in the phosphorus-free washing powder solution. 标准 , and the visible light absorption intensity Integ after the dyed fabric to be tested is soaked in the non-phosphate washing powder solution 待测 ;

[0018] 43) Calculate Integer 待测 With Integ 标准 The relative ratio R of the dyed fabric to be tested is obtained to obtain the water fastness of the dyed fabric to be tested, where:

[0019]

[0020] In the above scheme, after the absorption curve is measured, the absorption curve can be integrated by computer software to obtain the absorption intensity, and then the color of the phosphorus-free washing powder solution after the fabric is soaked can be digitized, thereby achieving the purpose of quantitatively characterizing the color fastness to water washing and improving the accuracy of the test results. Using the ratio of the absorption intensity obtained by the standard dye to the absorption intensity obtained by the dye to be tested as the test result of the color fastness to water washing is conducive to unifying the test standards and obtaining generally recognized test results.

[0021] When the calculated R is greater than 100%, it means that the color of the non-phosphorus washing powder solution after the dyed fabric to be tested is darker than the color of the standard dyed fabric soaking solution, that is, the dye to be tested is more severely decolorized, and thus the color fastness to water soaking is worse than the standard dye. When R is less than 100%, it means that the color of the non-phosphorus washing powder solution after the dyed fabric to be tested is lighter than the color of the standard dyed fabric soaking solution, that is, the degree of decolorization of the dye to be tested is lighter, and thus the color fastness to water soaking is better than the standard dye. When R=100%, it means that the color fastness to water soaking of the dye to be tested is basically the same as that of the standard dye.

[0022] Therefore, for the test results obtained by the above test method, if R>100%, it is judged as an unqualified product, and if R≤100%, it is judged as a qualified product.

[0023] Furthermore, after obtaining the water fastness of the dyed fabric to be tested, the test process is sorted and recorded, and the data obtained during the test process is archived.

[0024] In the above scheme, the measurement of the absorption curve and the calculation of the integral value (i.e., absorption intensity) can be completed by computer software, which reduces the number of manual operation steps and facilitates the recording and archiving of experimental data. The accumulation of experimental data in different testing processes makes it easier for manufacturers to understand the trend of product quality changes, which is conducive to optimizing product quality.

[0025] Furthermore, the concentration of the phosphorus-free laundry detergent solution in step 2) is 0.5-1.5 g / L, preferably 0.8-1.2 g / L, and more preferably 1 g / L.

[0026] Furthermore, the phosphorus-free washing powder includes 6% to 10% by mass of sodium dodecylbenzene sulfonate.

[0027] Further, in step 3), the phosphorus-free laundry detergent solution is heated to 55-65° C., and then the standard dyed fabric and the dyed fabric to be tested are immersed therein;

[0028] Preferably, the phosphorus-free laundry detergent solution is heated to 60°C.

[0029] Further, the standard dyed fabric and the dyed fabric to be tested are placed in a phosphorus-free laundry detergent solution kept at 55 to 65° C. for 0.5 to 1.5 h;

[0030] Preferably, the standard dyed fabric and the dyed fabric to be tested are placed in a phosphorus-free washing powder solution kept at 60° C. for 1 hour.

[0031] In the above scheme, the temperature of the phosphorus-free washing powder solution is controlled by water bath insulation, so that when the dyed fabric is left standing in the phosphorus-free washing powder solution, the temperature of the phosphorus-free washing powder solution is always maintained at the temperature when the dyed fabric is immersed.

[0032] Furthermore, in step 3), the bath ratio of the standard dyed fabric / the dyed fabric to be tested is 1:40 to 1:60, preferably 1:50.

[0033] In the above scheme, the bath ratio is the ratio between the mass (unit: g) of a single piece of fabric in step 1) and the volume (unit: ml) of the non-phosphorus washing powder solution required for soaking a piece of dyed fabric in step 3). By controlling the concentration of the non-phosphorus washing powder solution, the heating temperature, the soaking time of the dyed fabric, and the bath ratio of the dyed fabric, the color of the non-phosphorus washing powder solution obtained after the standard dyed fabric is soaked in water presents an appropriate color change, thereby providing a more accurate test result. Among them, the concentration and heating temperature of the non-phosphorus washing powder have a greater influence on the rate of decolorization of the dyed fabric, and controlling them within an appropriate range is more conducive to controlling the accuracy of the test results.

[0034] Furthermore, in step 1), the fabric is dyed to a dyeing depth of 1% to 5%, preferably 4%.

[0035] In the above scheme, for fabrics dyed with the same dye, if the dyeing depth of the fabrics is not exactly the same, even under the same soaking conditions, the obtained dyed fabric soaked in water with phosphorus-free laundry detergent solution will show different shades of color changes. Too dark or too light a color will cause the calculation accuracy of the absorption intensity ratio to decrease. Controlling the dyeing depth within an appropriate range can further improve the accuracy of the test results.

[0036] During actual testing, the dyeing depth required when the dye to be tested is used in actual products can be directly used. The test results obtained in this way can more truly reflect the water fastness of the textile products dyed with the dye to be tested, thereby more accurately controlling product quality.

[0037] Furthermore, when dyeing the fabric in step 1), the dye solution immersed in the fabric is heated to 98-100° C. at a uniform rate and kept warm for 30-40 minutes;

[0038] Preferably, the heating rate during the uniform heating process is 1 to 2°C / min;

[0039] More preferably, the temperature is increased to 98°C at a heating rate of 1.5°C / min and maintained at this temperature for 30 min.

[0040] In the above scheme, after the insulation process is completed, wait for the dye solution to cool down naturally, and then take out the fabric after the temperature drops to a certain degree, such as to 70°C, to avoid the risk of burns due to excessive temperature.

[0041] Furthermore, the fabric is washed after dyeing, and then dried at 60-80°C, preferably at 70°C.

[0042] Furthermore, when testing multiple dyes of the same variety but different batches, if it is not possible to test multiple dyes at the same time, at least ensure that the fabrics in step 1) are of the same type during each test, and try to ensure that the same batch of standard dyes are used during each test.

[0043] Since different fabric types will also have a certain impact on the test results, using the same type of fabric in multiple tests and comparing the multiple test results obtained in multiple test processes can more accurately reflect the differences in the water fastness performance of different batches of the same type of dye to be tested.

[0044] Although the standard dyes are standard dyes whose performance parameters are within the specified range, there are still some differences between different batches. If conditions permit, try to use the same batch of standard dyes as a reference for different batches of dyes to be tested during multiple tests, which can more accurately reflect the differences in water fastness between different batches of dyes to be tested.

[0045] During actual testing, the type of fabric used in the test process can be selected according to the type of fabric used by the dye to be tested in actual production, thereby being able to more truly reflect the water fastness level of the dyed fabric after the dye to be tested is dyed on a specific type of fabric.

[0046] Currently in the textile industry, the indicator of color fastness to water immersion has received more widespread attention during the use of nylon-spandex fabrics after dyeing. In step 1) of the above test method, the fabric is selected as nylon-spandex fabric, for example, nylon-spandex fabric containing 80% by mass of nylon and 20% by mass of spandex, and the obtained test results have a wider range of application.

[0047] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art.

[0048] In the test method of the present invention, the absorbance intensity of the soaking water solution obtained after the dyed fabric is soaked in water is measured to quantitatively characterize the color fastness to soaking in water of the dyed fabric, thereby realizing the quantitative test of the color fastness to soaking in water and improving the accuracy of the test result. At the same time, the standard dye and the dye to be tested are used to dye the fabric and subsequently process it under completely the same test conditions, and the absorbance intensity of the soaking water solution obtained by the standard dye and the absorbance intensity of the soaking water solution obtained by the dye to be tested are compared, and the relative ratio R of the two is taken as the test result, and the numerical value of the absorption intensity obtained by the dye to be tested is not directly used, so as to eliminate the errors caused by different dyeing equipment, operators, experimental equipment and other uncontrollable environmental factors as much as possible, and it is also conducive to unifying the test standard of the color fastness to soaking in water among different production enterprises.

[0049] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are a part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0051] Figure 1 is the process curve of dyeing in step 1) of Example 1 of the present invention;

[0052] Figure 2is the absorption curve of the solution after immersion measured in Example 1 of the present invention;

[0053] Figure 3 is the process curve of dyeing in step 1) of Example 2 of the present invention;

[0054] Figure 4 is the absorption curve of the solution after immersion measured in Example 2 of the present invention;

[0055] Figure 5 is the process curve of dyeing in step 1) of Example 3 of the present invention;

[0056] Figure 6 It is the absorption curve of the solution after immersion measured in Example 3 of the present invention.

[0057] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments are clearly and completely described below. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0059] Example 1

[0060] This example tests the water fastness of nylon-spandex fabric dyed with acid black 172. Acid black 172 dye whose water fastness has been recognized by customers is selected as a standard dye (referred to as standard dye A), and three dyes to be tested (respectively referred to as dyes to be tested A1, A2 and A3) are tested.

[0061] The basic parameters of the standard dye A used in this example are shown in Table 1 below.

[0062] Table 1 Basic parameters of standard dye A

[0063] Appearance Color light strength Moisture Water insoluble matter Solubility CIE L CIE CIE b CIE C CIE Black uniform powder Reddish 100％ 6.07％ 0.18％ 80g / L 16.44 0.23 -3.44 3.35 273.88

[0064] The test method specifically includes the following steps:

[0065] 1) Cut four pieces of nylon-spandex fabric (80% nylon, 20% spandex) with a mass of 1g for standby use. Weigh 0.25g of each of the standard dye A and the dyes to be tested A1, A2, and A3, and dissolve them separately. After they are fully dissolved, use 250ml volumetric flasks to make up the volume respectively. Transfer 40ml of the prepared solution to the dye vat, and add 10ml of acetic acid / sodium acetate buffer solution with pH=4.5 and 50ml of deionized water to make four equal concentration dye solutions of different dyes with a dyeing depth of 4%. Four pieces of nylon-spandex fabric are placed in one dye solution respectively and dyed in an infrared color tester. During the dyeing process, the dye solution is heated from 40°C to 98°C at a heating rate of 1.5°C / min, then kept warm for 30min, and then naturally cooled to 70°C. The dyeing process curve is as follows: Figure 1 As shown;

[0066] After dyeing, the fabric was fully washed with water and then dried in an oven at 70° C. to obtain a standard dyed fabric A dyed with a standard dye A, and test dyed fabrics A1, A2, and A3 dyed with test dyes A1, A2, and A3, respectively;

[0067] 2) dissolving a phosphorus-free washing powder containing sodium dodecylbenzene sulfonate (mass fraction 6% to 10%) to obtain a phosphorus-free washing powder solution with a concentration of 1 g / L;

[0068] 3) Heat the non-phosphate detergent solution to 60°C, transfer 50 ml to four beakers respectively, place the standard dyed fabric A and the dyed fabrics A1, A2, and A3 to be tested in the beakers respectively, stir gently with a glass rod to make the dyed fabrics completely immersed in the non-phosphate detergent solution, keep warm in a 60°C water bath, let stand for 1 hour and then take out;

[0069] 4) Using a UV-visible spectrophotometer, measure the absorption curve of four portions of non-phosphorus detergent solution after soaking dyed fabrics in the visible light range. The measurement results are as follows: Figure 2 As shown; then the SCT transmission colorimetric mixing system software is used to calculate the integral values ​​of the four absorption curves in the visible light range to obtain the absorption intensity, and the relative ratio R of the absorption intensity obtained by the test dyes A1, A2, and A3 to the absorption intensity obtained by the standard dye A is calculated respectively. The results are shown in the following Table 2;

[0070] 5) Organize and record the test process and archive the data obtained during the test.

[0071] Table 2 Absorption intensity and relative ratio R test results

[0072] Standard Dye A Dye to be tested A1 Dye to be tested A2 Dye to be tested A3 Absorption intensity 0.596 0.591 0.639 0.559 Relative ratio R(%) — 99.18 107.27 93.82

[0073] It can be seen from the above test results that R=107.27%>100% obtained by the tested dye A2, indicating that the color of the non-phosphate washing powder solution after soaking in water is darker than that of the standard dye A, and the dye fading is more serious, so the color fastness to soaking in water is worse than that of the standard dye A, and it is an unqualified product; R=93.82%<100% of the tested dye A3, indicating that the color of the non-phosphate washing powder solution after soaking in water is lighter than that of the standard dye, and the degree of dye fading is lighter, so the color fastness to soaking in water is better than that of the standard dye A, and it is a qualified product; R=99.18% obtained by the tested dye 1 is close to 100%, indicating that the color of the non-phosphate washing powder solution after soaking in water is close to that of the standard dye, so the color fastness to soaking in water is equivalent to that of the standard dye, and it is a qualified product.

[0074] By using the test method in this embodiment, the test results obtained can not only reflect the performance of the dye to be tested compared with the standard dye in terms of color fastness to water immersion, but also quantitatively reflect the specific level of color fastness to water immersion, thereby improving the accuracy and precision of the color fastness to water immersion test.

[0075] Example 2

[0076] In this embodiment, the water fastness of taslon fabric dyed with acid red 405 was tested. Acid red 405, whose water fastness has been recognized by customers, was selected as a standard dye (referred to as standard dye B), and three dyes to be tested (respectively referred to as test dyes B1, B2 and B3) were tested.

[0077] The basic parameters of the standard dye B used in this example are shown in Table 3 below.

[0078] Table 3 Basic parameters of standard dye B

[0079] Appearance Color light strength Moisture Water insoluble matter Solubility CIE L CIE CIE b CIE C CIE Red uniform powder Light blue 100％ 5.92％ 0.16％ 80g / L 32.69 41.85 0.77 41.86 1.06

[0080] The test method specifically includes the following steps:

[0081] 1) Cut four pieces of taslon fabric with a mass of 1g for use, weigh 0.25g of standard dye B and test dyes B1, B2, and B3 respectively, dissolve them separately, and use 250ml volumetric flasks to make up to volume after they are fully dissolved; transfer 10ml of the prepared solution to the dye vat respectively, and add 4ml of acetic acid / sodium acetate buffer solution with pH=4.5 and 86ml of deionized water to make four equal concentration dye solutions of different dyes, with a dyeing depth of 1%; put four pieces of taslon fabric into one dye solution respectively, and dye them in an infrared color tester. During the dyeing process, the dye solution is heated from 40°C to 98°C at a heating rate of 1.5°C / min, then kept warm for 30min, and then naturally cooled to 70°C. The dyeing process curve is as follows: Figure 3 As shown;

[0082] After dyeing, the fabric was fully washed with water and then dried in an oven at 70° C. to obtain a standard dyed fabric B dyed with a standard dye B, and test dyed fabrics B1, B2, and B3 dyed with test dyes B1, B2, and B3, respectively;

[0083] 2) dissolving a phosphorus-free washing powder containing sodium dodecylbenzene sulfonate (mass fraction 6% to 10%) to obtain a phosphorus-free washing powder solution with a concentration of 1 g / L;

[0084] 3) Heat the non-phosphorus detergent solution to 60°C, transfer 50 ml to four beakers respectively, place the standard dyed fabric B and the dyed fabrics to be tested B1, B2, and B3 into the beakers respectively, stir gently with a glass rod to make the dyed fabrics completely immersed in the non-phosphorus detergent solution, keep warm in a 60°C water bath, let stand for 1 hour and then take out;

[0085] 4) Using a UV-visible spectrophotometer, measure the absorption curve of four portions of non-phosphorus detergent solution after soaking dyed fabrics in the visible light range. The measurement results are as follows: Figure 4 As shown; then the SCT transmission colorimetric mixing system software is used to calculate the integral values ​​of the four absorption curves in the visible light range to obtain the absorption intensity, and the relative ratio R of the absorption intensity obtained by the test dyes B1, B2, and B3 to the absorption intensity obtained by the standard dye B is calculated respectively. The results are shown in the following Table 4;

[0086] 5) Organize and record the test process and archive the data obtained during the test.

[0087] Table 4 Absorption intensity and relative ratio R test results

[0088] Standard Dye B Dye to be tested B1 Dye to be tested B2 Dye to be tested B3 Absorption intensity 0.216 0.271 0.235 0.214 Relative ratio R(%) — 113.23 108.74 99.02

[0089] In this embodiment, R=113.23% obtained by the tested dye B1, and R=108.74% obtained by the tested dye B2, both greater than 100%, are unqualified products; R=99.02<100% obtained by the tested dye B3 is a qualified product.

[0090] Example 3

[0091] In this embodiment, the water fastness of nylon-spandex fabric dyed with acid yellow 128 was tested. Acid yellow 128, whose water fastness has been recognized by customers, was selected as a standard dye (referred to as standard dye C), and three dyes to be tested (respectively referred to as test dyes C1, C2 and C3) were tested.

[0092] The basic parameters of the standard dye C used in this example are shown in Table 5 below.

[0093] Table 5 Basic parameters of standard dye C

[0094] Appearance Color light strength Moisture Water insoluble matter Solubility CIE L CIE CIE b CIE C CIE Yellow uniform powder Reddish 100％ 5.99％ 0.11％ 30g / L 69.87 17.55 62.51 64.93 74.31

[0095] The test method specifically includes the following steps:

[0096] 1) Cut four pieces of nylon-spandex fabric (80% nylon, 20% spandex) with a mass of 1g for use. Weigh 0.25g of each of the standard dye C and the dyes to be tested C1, C2, and C3, and dissolve them separately. After they are fully dissolved, use 250ml volumetric flasks to make up to volume. Transfer 30ml of the prepared solution to the dye vat, and add 10ml of acetic acid / sodium acetate buffer solution with pH=4.5 and 60ml of deionized water to make four dye solutions of equal concentrations of different dyes, with a dyeing depth of 3%. Put four pieces of nylon-spandex fabric into one dye solution respectively, and dye them in an infrared color tester. During the dyeing process, heat the dye solution from 40℃ to 98℃ at a heating rate of 1.5℃ / min, then keep it warm for 30min, and then naturally cool it to 70℃. The dyeing process curve is as follows: Figure 5 As shown;

[0097] After dyeing, the fabric was fully washed with water and then dried in an oven at 70° C. to obtain a standard dyed fabric C dyed with the standard dye C, and test dyed fabrics C1, C2, and C3 dyed with the test dyes C1, C2, and C3, respectively;

[0098] 2) dissolving a phosphorus-free washing powder containing sodium dodecylbenzene sulfonate (mass fraction 6% to 10%) to obtain a phosphorus-free washing powder solution with a concentration of 1 g / L;

[0099] 3) Heat the non-phosphate detergent solution to 60°C, transfer 50 ml to four beakers respectively, place the standard dyed fabric C and the dyed fabrics to be tested C1, C2, and C3 into the beakers respectively, stir gently with a glass rod to make the dyed fabrics completely immersed in the non-phosphate detergent solution, keep warm in a 60°C water bath, let stand for 1 hour and then take out;

[0100] 4) Using a UV-visible spectrophotometer, measure the absorption curve of four portions of non-phosphorus detergent solution after soaking dyed fabrics in the visible light range. The measurement results are as follows: Figure 6 As shown; then the SCT transmission colorimetric mixing system software is used to calculate the integral values ​​of the four absorption curves in the visible light range to obtain the absorption intensity, and the relative ratio R of the absorption intensity obtained by the test dyes C1, C2, and C3 to the absorption intensity obtained by the standard dye C is calculated respectively. The results are shown in the following Table 6;

[0101] 5) Organize and record the test process and archive the data obtained during the test.

[0102] Table 6 Absorption intensity and relative ratio R test results

[0103] Standard Dye C Dye to be tested C1 Dye to be tested C2 Dye to be tested C3 Absorption intensity 0.426 0.469 0.384 0.395 Relative ratio R(%) — 110.20 90.15 92.63

[0104] In this embodiment, R=110.20% obtained by the tested dye C1>100%, which is an unqualified product; R=90.15 obtained by the tested dye C2, and R=92.63% obtained by the tested dye C3, both less than 100%, are qualified products.

[0105] Comparative Example 1

[0106] In this comparative example, the color fastness to water immersion is tested on the dyed fabrics obtained by dyeing with the dyes A1, A2 and A3 in Example 1 with reference to the test method of GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Soaping".

[0107] Specifically, the fabric type and dyeing conditions used in this comparative example are the same as those in Example 1, and the soaping liquid is replaced by the 1 g / L phosphate-free laundry detergent in Example 1. The preparation method of the combined sample in GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Soaping" and the subsequent treatment and comparison rating method after taking out the combined sample after washing are completed are referred to to obtain the rating of the color fastness to water immersion.

[0108] Table 7 below shows the test results of the water fastness of the dyes A1, A2 and A3 respectively obtained by using the test methods in Example 1 and Comparative Example 1.

[0109] Table 7 Comparison of test results of Example 1 and Comparative Example 1

[0110] Dye to be tested A1 Dye to be tested A2 Dye to be tested A3 Relative ratio R obtained in Example 1 99.18 107.27 93.82 Comparative Example 1 Grade 4 4 4

[0111] As can be seen from Table 7, since the human eye has a limit to the recognition of color differences, when the difference between two colors is not large, the human eye cannot distinguish the difference between the two, so the color fastness to water of the dyes A1, A2 and A3 obtained by the colorimetric rating method is the same level. However, the test method in Example 1 can accurately distinguish that the dyes A1 and A3 to be tested are qualified products, and the dye A2 to be tested is an unqualified product in terms of the indicator of color fastness to water, and there are obvious differences in the color fastness to water of the three.

[0112] It can be seen that the test results obtained by the test method of Example 1 are more objective and accurate. At the same time, because an instrument that is more sensitive to color differences is used in Example 1 and the test data is processed by software, the accuracy of the test results is further improved.

[0113] Test Example 1

[0114] This test example investigates the effect of different concentrations of the non-phosphate detergent solution on the test results. Only the concentration of the non-phosphate detergent solution used for soaking is changed. Other test conditions are the same as those in Example 1. The test results are shown in Table 8 below.

[0115] Table 8 Effect of phosphorus-free laundry detergent solution concentration on water fastness test results

[0116]

[0117]

[0118] As can be seen from Table 8 above, when the concentration of the non-phosphorus washing powder solution is too low (0.2 g / L), the color of the soaking solution obtained by the standard dye A is lighter and the absorption intensity is very low. Correspondingly, the color of the soaking solution obtained by each dye to be tested is also relatively lighter, and the R value of the test result is closer to 100% than the R value obtained by increasing the non-phosphorus washing powder solution. For example, the R value obtained by the dye A3 to be tested in the non-phosphorus washing powder solution at a concentration of 0.2 g / L is 99.12%, and the R value obtained in the non-phosphorus washing powder solution at a concentration of 1.5 g / L is 92.74%.

[0119] Especially for the dyes to be tested whose color fastness to water is close to that of the standard dyes, when the concentration of the non-phosphate detergent solution is too low, it may be impossible to accurately distinguish the performance of the dyes from the standard dyes due to the insufficient precision of the measuring instrument, thus causing erroneous test results. For example, when the concentration of the non-phosphate detergent solution of the dye A1 to be tested is 0.2g / L, the R value obtained is 100.06%>100%, which is judged as an unqualified product. When the concentration of the non-phosphate detergent solution is increased to 1-2g / L, the R value obtained is close to 99%, which is less than 100%, and it is actually a qualified product. It can be seen that after increasing the concentration of the non-phosphate detergent solution, the difference between the dye to be tested and the standard dye can be more clearly distinguished, and the test results are more accurate.

[0120] At the same time, when the concentration of the non-phosphorus washing powder solution is greater than or equal to 0.8g / L, the R value of the dye to be tested is significantly different from 100%, and when the concentration of the non-phosphorus washing powder solution is 1.2-2g / L, the R value of each dye to be tested no longer changes significantly. In order to avoid the non-phosphorus washing powder solution concentration being too high and affecting the absorption strength of the soaking water solution, or causing the waste of the non-phosphorus washing powder, the concentration of the non-phosphorus washing powder solution in this solution is preferably 0.8-1.2g / L, more preferably 1g / L.

[0121] Test Example 2

[0122] This test example investigates the influence of different temperatures of the non-phosphorus washing powder solution on the test results. Only the temperature of the non-phosphorus washing powder solution when the dyed fabric is immersed in the non-phosphorus washing powder solution is changed. Other test conditions are the same as those in Example 1. The test results are shown in the following Table 9.

[0123] Table 9 Effect of non-phosphorus detergent solution temperature on water fastness test results

[0124]

[0125]

[0126] It can be seen from Table 9 above that when the temperature of the phosphorus-free laundry detergent solution is low, the color of the aqueous solution obtained by standard dye A is lighter and the absorption intensity is lower. Correspondingly, the color of the aqueous solution obtained by each dye to be tested is also relatively lighter, and the R value of the test result is closer to 100%.

[0127] For dyes to be tested whose color fastness to water fastness is close to that of standard dyes, if the temperature of the non-phosphate washing powder solution is low, resulting in a low absorption intensity of the obtained water solution, the R value may be inaccurate due to the insufficient precision of the measuring instrument, and thus the performance of the dye to be tested and the standard dye cannot be accurately distinguished, resulting in erroneous test results. For example, when the temperature of the non-phosphate washing powder solution is 45°C, the R value obtained by the dye to be tested A1 is 100.61%>100%, which is judged as an unqualified product. When the temperature of the non-phosphate washing powder solution is increased to 60-75°C, the R value obtained is close to 99%, which is less than 100%, and it is actually a qualified product. It can be seen that after the temperature of the non-phosphate washing powder solution is increased, the absorption intensity of the water solution obtained by the standard dye A is increased, so the difference between the dye to be tested and the standard dye can be distinguished more clearly, and the test results are more accurate.

[0128] At the same time, when the temperature of the non-phosphorus washing powder solution is greater than or equal to 55° C., for the dyes A2 and A3 to be tested, the measured R values ​​are already significantly different from 100%, while for the dye A1 to be tested, its performance is closest to the standard dye, and when the temperature of the non-phosphorus washing powder solution is 60-75° C., accurate test results can also be obtained. In this solution, the temperature of the non-phosphorus washing powder solution is preferably 55-65° C., more preferably 60° C.

[0129] Test Example 3

[0130] This test example investigates the effect of different soaking times of dyed fabrics in a phosphorus-free laundry detergent solution on the test results. Only the standing time of the dyed fabrics after being immersed in the phosphorus-free laundry detergent solution is changed. Other test conditions are the same as those in Example 1. The test results are shown in Table 10 below.

[0131] Table 10 Effect of immersion time on water fastness test results

[0132]

[0133] As can be seen from Table 10 above, when the soaking time is too short (10 minutes), the color of the soaking solution obtained by the standard dye A is lighter and the absorption intensity is lower. Correspondingly, the color of the soaking solution obtained by each test dye is also relatively lighter, and the R value of the test result is closer to 100% than the R value obtained when the soaking time is longer. For example, the R value obtained by the test dye A1 when the soaking time is 10 minutes is 99.81%, while the R value obtained when the soaking time is 1 hour is 99.18%.

[0134] Especially for the dye to be tested whose color fastness to water immersion is close to that of the standard dye, if the immersion time is insufficient, it may be impossible to accurately distinguish the performance of the dye and the standard dye due to the insufficient precision of the measuring instrument, thereby causing erroneous test results. After appropriately extending the immersion time, the difference between the dye to be tested and the standard dye can be clearly distinguished, and the test result is more accurate. At the same time, in order to ensure the test efficiency and avoid unnecessary extension of the immersion time, the preferred immersion time in this scheme is 30min to 1.5h, more preferably 1h.

[0135] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A method for testing the color fastness of acid dyes to water, characterized in that: The steps include: 1) cutting at least two pieces of fabrics of the same specifications and of the same mass, wherein one piece of fabric is dyed with a standard dye and the other piece of fabric is dyed with a dye to be tested, dyeing them under the same conditions, and drying them to obtain a standard dyed fabric and a dyed fabric to be tested; the standard dye is a standard dye corresponding to the dye to be tested; 2) dissolving the non-phosphorus washing powder to obtain a non-phosphorus washing powder solution; 3) Immerse the standard dyed fabric and the dyed fabric to be tested in equal amounts of phosphorus-free detergent solution, stir, and take out after standing for a certain period of time; 4) taking the phosphorus-free washing powder solution after soaking the standard dyed fabric and the dyed fabric to be tested in step 3), measuring the absorption intensity thereof in the visible light range respectively, and comparing them to obtain the test result of the color fastness to water immersion; Step 4) specifically includes the following steps: 41) Take the non-phosphorus washing powder solution after soaking the standard dyed fabric and the non-phosphorus washing powder solution after soaking the dyed fabric to be tested, and use a UV-visible spectrophotometer to measure their absorption curves in the visible light range, and obtain the absorption curve C of the non-phosphorus washing powder solution after soaking the standard dyed fabric in the visible light range. 标准 , and the absorption curve C in the visible light range after the dyed fabric to be tested is soaked in the non-phosphorus washing powder solution 待测 ; 42) Calculate the absorption curve C obtained in step 41) respectively 标准 and absorption curve C 待测 The integral value in the visible light range is used to obtain the visible light absorption intensity Integ after the standard dyed fabric is soaked in the phosphorus-free washing powder solution. 标准 , and the visible light absorption intensity Integ after the dyed fabric to be tested is soaked in the non-phosphate washing powder solution 待测 ; 43) Calculate Integer 待测 With Integ 标准 The relative ratio R of the dyed fabric to be tested is obtained to obtain the water fastness of the dyed fabric to be tested, where:

2. The method for testing the color fastness of acid dyes to water immersion according to claim 1, characterized in that: The concentration of the phosphorus-free washing powder solution in step 2) is 0.5-1.5 g / L.

3. The method for testing the color fastness of acid dyes to water immersion according to claim 2, characterized in that: The concentration of phosphorus-free laundry detergent solution is 0.8-1.2 g / L.

4. The method for testing the color fastness of acid dyes to water immersion according to claim 3, characterized in that: The concentration of phosphorus-free laundry detergent solution is 1g / L.

5. The method for testing the color fastness of acid dyes to water immersion according to claim 2, characterized in that: The phosphorus-free washing powder comprises 6% to 10% by mass of sodium dodecylbenzene sulfonate.

6. The method for testing the color fastness of acid dyes to water immersion according to any one of claims 1 to 5, characterized in that: In step 3), the phosphorus-free washing powder solution is heated to 55-65° C., and then the standard dyed fabric and the dyed fabric to be tested are immersed in the solution.

7. The method for testing the color fastness of acid dyes to water immersion according to claim 6, characterized in that: The phosphorus-free washing powder solution was heated to 60°C.

8. The method for testing the color fastness of acid dyes to water immersion according to claim 6, characterized in that: The standard dyed fabric and the dyed fabric to be tested are placed in a phosphorus-free laundry detergent solution kept at 55-65°C for 0.5-1.5h.

9. The method for testing the color fastness of acid dyes to water immersion according to claim 8, characterized in that: The standard dyed fabric and the dyed fabric to be tested are placed in a phosphorus-free laundry detergent solution kept at 60°C for 1 hour.

10. The method for testing the color fastness of acid dyes to water immersion according to any one of claims 1 to 5, characterized in that: In step 3), the bath ratio of the standard dyed fabric to the dyed fabric to be tested is 1:40 to 1:

60.

11. The method for testing the color fastness of acid dyes to water immersion according to claim 10, characterized in that: The bath ratio is 1:

50.

12. The method for testing the color fastness of acid dyes to water immersion according to any one of claims 1 to 5, characterized in that: In step 1), the fabric is dyed with a dyeing depth of 1% to 5%.

13. The method for testing the color fastness of acid dyes to water immersion according to claim 12, characterized in that: The dyeing depth was 4%.

14. The method for testing the color fastness of acid dyes to water immersion according to claim 12, characterized in that: When dyeing the fabric in step 1), the dye solution immersed in the fabric is heated to 98-100° C. at a uniform rate and kept warm for 30-40 minutes.

15. The method for testing the color fastness of acid dyes to water immersion according to claim 14, characterized in that: The heating rate during the uniform heating process is 1-2°C / min.

16. The method for testing the color fastness of acid dyes to water immersion according to claim 15, characterized in that: The temperature was raised to 98°C at a heating rate of 1.5°C / min and kept at this temperature for 30 min.

17. The method for testing the color fastness of acid dyes to water immersion according to claim 14, characterized in that: After dyeing, the fabric is washed and then dried at 60-80°C.

18. The method for testing the color fastness of acid dyes to water immersion according to claim 17, characterized in that: The drying temperature is 70°C.

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