Low-temperature soaping agent for reactive dyeing of silk fabric and soaping method

Abstract

The present invention discloses a low-temperature soaping agent for reactive dyeing of silk fabrics and a soaping method. By weight percentage, it consists of the following two components: 70%-80% of polyethoxy alkynediol gemini surfactants and 20%-30% of zwitterionic polyvinylpyridine derivatives. The present invention has the advantages of low consumption of the soaping agent, low soaping temperature, good soaping effect, high wet treatment color fastness, energy conservation and emission reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of textile dyeing, and particularly relates to a low-temperature soaping agent for reactive dyeing of silk fabrics and a soaping method. Background Art

[0002] Silk products are deeply favored by consumers due to their bright colors, gorgeous appearance, comfortable wearing, soft handfeel, and good drapability. Silk fabrics are commonly used as high-grade summer, spring and autumn fabrics, underwear, and decorations, which require both good color brightness and gloss, and high dyeing fastness. In actual production, acidic and neutral dyes are mainly used to dye silk fabrics, and direct dyes are selected for individual colors to make up for the deficiency of the acidic dye chromatogram. The acidic dye chromatogram is relatively complete and the colors are bright, but the wet treatment fastness such as soaping fastness and wet rubbing fastness is poor, especially the wet treatment fastness of acidic dyes with a triarylmethane structure is even worse. Neutral dyes mainly composed of 1:2 metal complex dyes, although their wet treatment fastness is better than that of weak acidic dyes, their colors are duller and are mainly used for dyeing dark and deep colors. Therefore, there are defects in the dyeing fastness and color brightness of existing medium and dark-colored dyed silk fabrics.

[0003] Reactive dyes are the only reactive dyes that can bind to silk fibers by covalent bonds. Therefore, dyeing silk fabrics with reactive dyes is expected to fundamentally solve the problem of poor wet treatment fastness such as soaping fastness and wet rubbing fastness existing in the current acidic and neutral dyeing of silk fabrics. Based on comprehensive literature reports and domestic experience in using reactive dyes for dyeing, the temperature of silk reactive dyeing is highly related to the type of reactive dyes selected. In the early stage when there were not many varieties of reactive dyes, more wool reactive dyes such as difluorochloropyrimidine type and α-bromoacrylamide type were used for dyeing at a high temperature of 90-95°C. Now, it tends to use medium-temperature reactive dyes for dyeing at 60-65°C, and the fixation reaction is generally carried out under alkaline conditions. This dyeing method has the benefit of energy saving. When using reactive dyes for dyeing, after the silk fabric is dyed, like the reactive dyeing of cotton fabrics, it is necessary to carry out high-temperature soaping at 90-95°C with a soaping agent to wash off the floating color (including hydrolyzed dyes and unreacted dyes) in order to obtain good wet treatment fastness. Although there is a covalent bond between reactive dyes and silk fibers, if the floating color is not removed sufficiently after dyeing, good wet treatment fastness cannot be obtained. The multi-step washing and soaping after reactive dyeing lead to an increase in water consumption and energy consumption. Therefore, how to reduce the washing process after reactive dyeing and lower the soaping temperature to achieve the purpose of water saving, energy saving and consumption reduction is an important topic worthy of research.

[0004] In actual production, crepe silk fabrics (such as double crepe and georgette) are usually dyed in a rope dyeing machine. For dark and intense color varieties, long-term high-temperature acid dyeing can easily lead to excessive friction between the fabric and the fabric, as well as between the fabric and the inner wall of the dyeing machine, resulting in fuzzing, pilling, and a worn appearance on the surface of the dyed product, that is, the appearance of gray injury defects. Therefore, how to reduce the dyeing temperature and washing temperature, and reduce or avoid the gray injury defects of dyed crepe silk fabrics is an important technical issue that should be concerned about in actual production. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of high energy consumption in high-temperature soaping of silk fabrics dyed with reactive dyes, gray injury defects easily occurring in high-temperature rope soaping of crepe fabrics, and poor wet treatment color fastness of dark and intense color varieties, and to provide a low-temperature soaping agent and a soaping method for reactive dyeing of silk fabrics.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0007] A low-temperature soaping agent for reactive dyeing of silk fabrics is composed of the following two components by weight percentage:

[0008] Polyethoxyalkynediol-based gemini surfactant 70%-80%,

[0009] Amphoteric ionic polyvinylpyridine derivative 20%-30%.

[0010] The polyethoxyalkynediol-based gemini surfactant has the following structural formula:

[0011] Where the number of ethoxy groups n + m = 30.

[0012] The amphoteric ionic polyvinylpyridine derivative has the following structural formula:

[0013]

[0014] A low-temperature soaping method for silk fabrics after reactive dyeing is to perform low-temperature soaping on the silk fabrics after reactive dyeing in a soaping bath containing the above-mentioned low-temperature soaping agent.

[0015] The concentration of the low-temperature soaping agent in the soaping bath is 0.75 - 1.25 g / L.

[0016] Sodium bicarbonate is also added to the soaping bath, and the concentration of sodium bicarbonate is 0.5 - 1 g / L.

[0017] The low-temperature soaping temperature is 60 - 70 °C, and the time is 15 - 25 min.

[0018] The low-temperature soaping agent for reactive dyeing of silk fabrics according to the present invention is composed of polyethoxyalkynediol gemini surfactants and zwitterionic polyvinylpyridine derivatives, which all play different important roles during the soaping process. The polyethoxyalkynediol gemini surfactants have super wetting effects, can promote the swelling of silk fibers at low temperatures, and thus are beneficial to the diffusion of hydrolyzed dyes dyed on silk fibers during the dyeing process from the inside of the fibers and desorption into the solution. The zwitterionic polyvinylpyridine derivatives can interact with or bind to the desorbed hydrolyzed dyes, thereby preventing the hydrolyzed dyes desorbed from the dyed fabric from redepositing on the fibers. When the low-temperature soaping agent is applied, the added sodium bicarbonate has two functions: on the one hand, it makes the soaping solution weakly alkaline, promoting the desorption of hydrolyzed dyes; on the other hand, it makes the silk fibers in a weakly alkaline environment, promoting the reaction of a small amount of unfixed but still reactive reactive dyes during the dyeing process with the silk fibers during the soaping process. The unique functions of the two components of the low-temperature soaping agent and the function of the added sodium bicarbonate during application can all effectively increase the removal amount of floating color on silk fabrics, improve the soaping efficiency, and endow the dyed silk fabrics with high color fastness to washing and rubbing.

[0019] The beneficial effects of the present invention are:

[0020] (1) The low-temperature soaping agent of the present invention has excellent wetting and fiber swelling promoting capabilities, and has advantages such as low foaming and no alkylphenol polyoxyethylene ether compounds (APEO).

[0021] (2) It has the advantages of low dosage of soaping agent, low soaping temperature, good soaping effect, high wet treatment color fastness, energy saving and emission reduction.

[0022] (3) During the soaping process, a small amount of unfixed but still reactive reactive dyes on the silk fibers can still continue to react with the silk fibers during the soaping process, which helps to improve the wet treatment color fastness of the dyed silk fabrics.

[0023] (4) It can reduce or avoid the gray injury defects caused by the friction between fabrics during the high-temperature rope soaping process of crepe fabrics. Specific embodiments

[0024] The technical solutions of the present invention will be further specifically described below through specific embodiments.

[0025] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0026] The polyethoxyalkynediol gemini surfactant in the present invention has the following structural formula:

[0027] wherein the number of ethoxy groups n + m = 30

[0028] The polyethoxyalkynediol gemini surfactant is a commercially available product Surfynol 485 (Air Products and Chemicals, Inc., USA).

[0029] The zwitterionic polyvinylpyridine derivative has the following structural formula:

[0030]

[0031] The zwitterionic polyvinylpyridine derivative is a commercially available product Chromabond S-100 (Specialty Chemicals Company, USA), and its molecular weight is 10 - 40×10 3 .

[0032] Example 1

[0033] (1) Prepare a low-temperature soaping agent according to the following mass percentages: 75% of polyethoxyalkynediol gemini surfactant and 25% of polyvinylpyridine derivative. Stir and mix evenly at room temperature to obtain the low-temperature soaping agent 1 for reactive dyeing of silk fabrics.

[0034] (2) Prepare a dyeing solution composed of 4% (relative to the fabric mass percentage) of reactive red LB-3BF, 70 g / L of sodium sulfate, and 0.3 g / L of leveling agent Peregal O. The bath ratio is 1:20. Add crepe silk fabrics, start dyeing at room temperature, raise the temperature to 60°C, add 2 g / L of soda ash and continue dyeing for 70 min. After dyeing, wash with clear water; after dyeing, perform soaping according to the following method: Immerse the dyed fabric washed with clear water in a mixed solution of 1 g / L of low-temperature soaping agent 1 and 0.5 g / L of sodium bicarbonate, and soap at 70°C for 20 min, and finally wash with clear water.

[0035] Example 2

[0036] (1) Prepare a low-temperature soaping agent according to the following mass percentages: 80% of polyethoxyalkynediol gemini surfactant and 20% of polyvinylpyridine derivative. Stir and mix evenly at room temperature to obtain the low-temperature soaping agent 2 for reactive dyeing of silk fabrics.

[0037] (2) Prepare a dyeing solution composed of 4% (relative to the fabric mass percentage) of reactive yellow LB-4RFN, 70 g / L of sodium sulfate, and 0.3 g / L of leveling agent Peregal O. The bath ratio is 1:20. Add crepe silk fabrics, start dyeing at room temperature, raise the temperature to 60°C, add 2 g / L of soda ash and continue dyeing for 70 min. After dyeing, wash with clear water; after dyeing, perform soaping according to the following method: Immerse the dyed fabric washed with clear water in a mixed solution of 1.25 g / L of low-temperature soaping agent 2 and 1 g / L of sodium bicarbonate, and soap at 60°C for 25 min, and finally wash with clear water.

[0038] Example 3

[0039] (1) Prepare a low-temperature soaping agent according to the following mass percentages: 70% of polyethoxy alkynediol gemini surfactant and 30% of polyvinylpyridine derivative. Stir and mix evenly at room temperature to obtain the low-temperature soaping agent 3 for reactive dyeing of silk fabrics.

[0040] (2) Prepare a dyeing solution composed of 4% (relative to the fabric mass percentage) of reactive dark blue LB-2GLN, 70 g / L of sodium sulfate, and 0.3 g / L of leveling agent Peregal O. The bath ratio is 1:20. Add the crepe silk fabric, start dyeing at room temperature, heat up to 60 °C, add 2 g / L of soda ash and continue dyeing for 70 min, and then wash with clear water after dyeing; after dyeing, carry out soaping according to the following method: Immerse the dyed fabric washed with clear water in a mixed solution of 0.75 g / L of low-temperature soaping agent 3 and 0.75 g / L of sodium bicarbonate, and carry out soaping at 70 °C for 15 min, and finally wash with clear water.

[0041] Control Example

[0042] Prepare three dyeing solutions respectively composed of 4% (relative to the fabric mass percentage) of reactive red LB-3BF, 4% (relative to the fabric mass percentage) of reactive yellow LB-4RFN, 4% (relative to the fabric mass percentage) of reactive dark blue LB-2GLN, 70 g / L of sodium sulfate, and 0.3 g / L of leveling agent Peregal O. The bath ratio is 1:20. Add the crepe silk fabric, start dyeing at room temperature, heat up to 60 °C, add 2 g / L of soda ash and continue dyeing for 70 min, and then wash with clear water after dyeing; after dyeing, carry out soaping according to the following method: Immerse the dyed fabric washed with clear water in a 3 g / L solution of commercially available soaping agent 506G at 90 °C for 15 min, and finally wash with clear water.

[0043] Collect the solutions after soaping above, and measure the absorbance of the soaping solution at the maximum absorption wavelength using an ultraviolet-visible absorption spectrometer. A high absorbance indicates a large amount of floating color washed off from the dyed silk fabric and good soaping effect. Respectively, according to Test Method 1 of GB / T 3921–2008 "Textiles - Tests for colour fastness - Colour fastness to soaping" and GB / T 3920–2008 "Textiles - Tests for colour fastness - Colour fastness to rubbing", measure the colour fastness to soaping and rubbing of the dyed silk fabric after soaping and washing with clear water. A high colour fastness grade also means good soaping effect. The test results are shown in Table 1 and Table 2.

[0044] As can be seen from Table 1, for silk fabrics dyed with three dyes, namely Reactive Red LB-3BF, Reactive Yellow LB-4RFN, and Reactive Dark Blue LB-2GLN, after soaping with the low-temperature soaping agent of the present invention at low temperature, the absorbance of the soaping liquor at the maximum absorption wavelength is significantly less than that of the soaping liquor of the commercially available soaping agent 506G soaped at 90°C. In addition, Table 2 shows that the wet treatment color fastness (soaping color fastness and wet rubbing color fastness) of the dyed fabrics obtained by soaping with the low-temperature soaping agent of the present invention at low temperature is generally half a grade higher than that of the dyed fabrics soaped with the commercially available soaping agent 506G at 90°C.

[0045] In addition, the silk fabrics dyed with reactive dyes and then soaped were visually observed for the condition of becoming old and pilling due to friction on the surface (i.e., greying). The surface of the silk fabrics dyed with reactive dyes and soaped at low temperature is smooth and has a soft luster, without greying, while the surface of the silk fabrics dyed with red and dark blue reactive dyes and soaped at high temperature has slight greying.

[0046] The above examples and comparative examples show that when the low-temperature soaping agent and soaping method of the present invention are used to soap the silk fabrics dyed with reactive dyes, good soaping effects can be obtained, the wet treatment color fastness of the deeply and darkly dyed silk fabrics is improved, and the surface of the silk fabrics is smooth, has a soft luster, and has no greying.

[0047] The above-described examples are only a preferred solution of the present invention and do not impose any formal restrictions on the present invention. There are other variations and modifications without exceeding the technical solutions described in the claims.

[0048] Absorbance of the soaping liquor of three silk fabrics dyed with reactive dyes in the examples and comparative examples in Table 1

[0049]

[0050] Dyeing fastness of three silk fabrics dyed with reactive dyes in the examples and comparative examples after soaping in Table 2

[0051]

[0052] The above-described examples are only a preferred solution of the present invention and do not impose any formal restrictions on the present invention. There are other variations and modifications without exceeding the technical solutions described in the claims.

Claims

1. A low-temperature soaping agent for reactive dyeing of silk fabrics, characterized in that, by weight percentage, it is composed of the following two components: Polyethoxy alkynediol gemini surfactant 70%-80%, Amphoteric polyvinylpyridine derivative 20%-30%; The polyethoxy alkynediol gemini surfactant has the following structural formula: , where the number of ethoxy groups n + m = 30; The amphoteric polyvinylpyridine derivative has the following structural formula: ； The low-temperature soaping temperature is 60-70°C.

2. A low-temperature soaping method for silk fabrics after reactive dyeing, characterized in that: The silk fabric after reactive dyeing is subjected to low-temperature soaping in a soaping bath containing the low-temperature soaping agent described in Claim 1; the low-temperature soaping temperature is 60-70°C and the time is 15-25 min.

3. According to the low-temperature soaping method described in Claim 2, characterized in that: The concentration of the low-temperature soaping agent in the soaping bath is 0.75-1.25 g / L.

4. According to the low-temperature soaping method described in Claim 2, characterized in that: Sodium bicarbonate is also added to the soaping bath, and the concentration of sodium bicarbonate is 0.5-1 g / L.

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