Processing method for deepening and fixing color of dye dye dyed silk of dioscorea cirrhosa

Abstract

The invention belongs to the field of dyeing and finishing of silk products, and particularly discloses a processing method for darkening and fixing color of dye-dyed silk of dioscorea cirrhosa, which comprises the following steps: preparing an oxidizing agent aqueous solution with the concentration of 1-50g / L, finishing the dye-dyed silk of dioscorea cirrhosa by using the oxidizing agent aqueous solution, and reacting at 40-100 DEG C for 1-10 minutes; the silk subjected to darkening and color fixing treatment is obtained; and washing the silk subjected to darkening and color fixing treatment with water, and then drying. The color depth of the silk treated by the method is remarkably increased, and the color fastness to washing and the color fastness to wet rubbing of the silk are both improved.

Description

Technical Field

[0001] This invention belongs to the field of dyeing and finishing of silk products (classic silk products), specifically a processing method for deepening and fixing the color of silk dyed with yam pigment. Background Technology

[0002] Xiangyun silk (also known as yam yarn) is a traditional Chinese silk treasure, and its production process is listed as a national intangible cultural heritage. Traditional Xiangyun silk uses mulberry silk as the base material, which is repeatedly dyed with yam juice, dried, and processed using special techniques such as covering with river mud. The finished product has a unique dark brown luster, cool and breathable properties, and a texture that is "soft as gauze and bright as lacquer." However, the traditional process has significant defects in color fastening, severely restricting the high-end and branded development of its products. Specifically: First, color fastness is poor. The traditional process relies on natural light and air oxidation for color fastening, which is greatly affected by weather, temperature, and humidity, easily leading to substandard color fastness (especially water washing and rubbing fastness). Its wet rubbing fastness is generally only grade 2, failing to meet the national standard (not lower than grade 3). Long-term use of Xiangyun silk products easily results in fading and whitening. Secondly, sun exposure is essentially the dyeing and color-fixing process, which is complex and inefficient due to its reliance on manual labor and weather conditions. It requires repeated dyeing and sun exposure dozens of times, with a production cycle of 15-20 days. It is highly dependent on manual labor, making standardized production difficult, resulting in low yield and high costs. Future industrial-scale preparation still needs to solve the problem of fixing dioscorea pigment on silk.

[0003] In recent years, researchers have attempted to improve color-fixing performance using chemical auxiliaries, such as metal salt mordants (the optimal process for dyeing and increasing the weight of silk fabrics with yam extract and the modification effect of metal ion post-treatment [J]. Sericultural Science, 2008, 34(4): 694-700), quaternary ammonium salts (research on the dyeing and finishing process of yam dye and its imitation of Xiangyun yarn [D]. Master's thesis of Zhejiang University of Technology, 2022), or artificial simulated sunlight (such as patent CN 202211539475.9). However, the following problems exist: color fixing with metal salts (such as commonly used ferrous sulfate, ferrous sulfate, copper sulfate, etc.) will change the inherent color of yam yarn and destroy the natural texture of yam yarn. The residual metal ions do not meet environmental protection standards. Quaternary ammonium salts have a fishy smell, which may bring consumers an unpleasant olfactory experience. Physical methods have high equipment investment and high energy consumption, resulting in high processing costs.

[0004] Therefore, given the needs of the consumer market and the industrial needs of producing ramie fabric, there is an urgent need to develop a green and efficient method for deepening and fixing the color of ramie fabric that can be seamlessly integrated with traditional processes, so as to improve color fastness while taking into account both eco-friendliness and the needs of large-scale production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a processing method for dyeing silk with yam pigment to deepen and fix the color.

[0006] To address the aforementioned technical problems, this invention provides a method for deepening and fixing the color of silk dyed with yam pigment, comprising the following steps: 1) Prepare an aqueous solution of oxidant with a concentration of 1~50 g / L (preferably 1.5~45 g / L), and use the aqueous solution of oxidant to finish the silk dyed with dioscorea pigment, and then react at 40~100 ℃ for 1~10 min (preferably at 42~95 ℃ for 2~8 min); to obtain the fabric (silk) after color enhancement and fixation treatment. 2) Wash and dry the fabric after the color-fixing treatment obtained in step 1) (and finally roll it up and put it into storage).

[0007] An improvement to the processing method of dyeing silk with yam pigment according to the present invention: The finishing method is spraying or padding; When spraying, the dosage of the oxidant aqueous solution is: 200±20 mL / m 2 Fabrics; When rolling is used, the liquid content of the rolling strip is controlled to be 95%~105% (preferably 102~103%). The padding liquid retention rate = (wet weight of the fabric after padding - dry weight of the fabric before padding) / dry weight of the fabric before padding.

[0008] As a further improvement to the processing method of dyeing silk with yam pigment of the present invention to deepen and fix the color: The oxidizing agent is at least one of sodium hypochlorite and sodium hypophosphite.

[0009] As a further improvement to the processing method of dyeing silk with yam pigment of the present invention to deepen and fix the color: The yam pigment-dyed silk includes yam yarn (also known as fragrant cloud yarn) made by the traditional sun-drying process and yam pigment-dyed silk prepared by the modern repeated dyeing / drying process.

[0010] As a further improvement to the processing method of dyeing silk with yam pigment of the present invention to deepen and fix the color: In step 2): the fabric after the color-fixing treatment is thoroughly washed with pure water (1 to 3 times, until the washing solution can no longer change the color of the potassium iodide test paper), and then dried at 120±10 ℃ for 20±2 s.

[0011] The principle of this invention is as follows: Dioscorea opposita pigment-dyed silk (Dioscorea opposita-dyed silk fabric) is treated with an oxidizing agent to oxidize the polyphenolic pigments of Dioscorea opposita into benzoquinones, altering the conjugated structure of the pigments. After treatment, the fabric changes from its original brown color to a darker brown, achieving the desired color deepening. Simultaneously, the oxidation treatment converts water-soluble Dioscorea opposita pigments into water-insoluble pigments, thereby fixing the Dioscorea opposita pigments to the silk surface and significantly improving the wash fastness and wet rubbing fastness of the Dioscorea opposita-dyed silk.

[0012] The treated fabric exhibits a significant increase in color depth, and its colorfastness to washing is improved to level 3-4 or higher, while its colorfastness to wet rubbing reaches level 3 or higher, fully meeting national standards. The method of this invention is economical and easily implemented on conventional equipment, resulting in low processing costs. Furthermore, this method is environmentally friendly, provides excellent colorfastness, and has significant application value. Detailed Implementation

[0013] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto: The yam pigment-dyed silk described in this invention is any one of the following: Fabric I: Traditional Xiangyun yarn finished product, color depth K / S value is 11.8, color fastness to washing is grade 3, color fastness to dry rubbing is grade 2-3, color fastness to wet rubbing is grade 2; Fabric II: A yam dyed fabric prepared by a modern repeated dyeing / drying process, with a color depth K / S value of 11.1, and color fastness to washing, dry rubbing, and wet rubbing all at grade 2. The dyeing process can be referenced from "Study on the Changes in Fabric Structure and Properties during the Preparation of Yam Yam" (Master's Thesis, Zhejiang Sci-Tech University, 2024): The silk fabric was repeatedly immersed and dried with 10 g / L yam dye liquor, repeated 20 times, with a liquor content of about 125% for each immersion, an immersion temperature of 45℃, an immersion time of 5 min, a liquor ratio of 1:30, and a drying temperature of 45℃.

[0014] The oxidants used were purchased from Shanghai Aladdin Reagent Co., Ltd., and were all of analytical grade.

[0015] Example 1-1: Prepare a 25 g / L sodium hypochlorite aqueous solution, and apply the sodium hypochlorite solution to the yam dyed silk (fabric II) by spraying at a dosage of 200 mL / m. 2 The fabric was heated at 50 ℃ for 6 min, and then thoroughly washed twice with pure water (until the washing solution could no longer change the color of the potassium iodide test paper). It was then dried at 120 ℃ (about 20 s) and finally rolled up and stored to obtain yam pigment-dyed silk with enhanced color fixation.

[0016] Examples 1-2: Prepare a 1.5 g / L sodium hypochlorite aqueous solution, and apply the sodium hypochlorite solution to the yam dyed silk (fabric II) by spraying at a dosage of 200 mL / m. 2 The fabric was heated at 80 ℃ for 3 min, and then thoroughly washed twice with pure water. It was then dried at 120 ℃ (about 20 s) and finally rolled up and stored to obtain yam pigment-dyed silk with enhanced color fixation.

[0017] Examples 1-3: Prepare a 10 g / L sodium hypochlorite aqueous solution. Apply the sodium hypophosphite solution to the yam pigment-dyed silk (fabric II) by padding. The padding liquid rate is 102%. React at 42 ℃ for 8 min. Finally, wash the color-fixed fabric twice with pure water and dry at 120 ℃ (about 20 s). Finally, roll it up and put it into storage to obtain the yam pigment-dyed silk with enhanced color fixation.

[0018] Examples 1-4: Sodium hypochlorite in Example 1-1 was replaced with sodium hypophosphite, the concentration remained unchanged, and the rest was the same as in Example 1-1.

[0019] Examples 1-5: Sodium hypochlorite in Examples 1-2 was replaced with sodium hypophosphite, while the concentration remained unchanged, and the rest was the same as in Examples 1-2.

[0020] Examples 1-6: Sodium hypochlorite in Examples 1-3 was replaced with sodium hypophosphite, while the concentration remained unchanged, and the rest was the same as in Examples 1-3.

[0021] Examples 1-7: The “25 g / L sodium hypochlorite aqueous solution” in Example 1-1 was replaced with the following composite oxidant aqueous solution: an aqueous solution of 12.5 g / L sodium hypochlorite and 12.5 g / L sodium hypophosphite; the rest is the same as in Example 1-1.

[0022] Example 2-1: Prepare a 45 g / L sodium hypophosphite aqueous solution. Apply the sodium hypophosphite solution to the ramie fabric (fabric I) by padding, with a padding liquid rate of 103%. React at 95 ℃ for 2 min. Finally, wash the color-fixed fabric twice with pure water and dry at 120 ℃ (about 20 s). Finally, roll it up and put it into storage to obtain the ramie fabric with deepened color fixation.

[0023] Example 2-2: A composite oxidant aqueous solution containing 2.5 g / L sodium hypochlorite and 2.5 g / L sodium hypophosphite was prepared. The composite oxidant aqueous solution was applied to the ramie fabric (fabric I) by padding, with a padding liquid rate of 102%. The reaction was carried out at 95 ℃ for 8 min. Finally, the fabric after color fixation treatment was thoroughly washed twice with pure water and dried at 120 ℃ (about 20 s). Finally, it was rolled up and stored to obtain the ramie fabric with deepened color fixation.

[0024] Test methods: The color fastness to washing of dyed products was tested using AATCC 61-2003 "Household and commercial washing fastness: rapid method"; the color fastness to dry / wet rubbing of dyed fabrics was tested using GB / T 3920-2008 "Textiles - Tests for color fastness - Color fastness to rubbing". The color depth index (K / S value) of the fabrics was tested using a DataColor SF600X colorimeter.

[0025] The color depth and color fastness test results of the products obtained in the above embodiments are shown in Table 1.

[0026] Table 1

[0027] According to Table 1, we can see that: Compared to the untreated yam pigment-dyed fabric (referred to as Fabric II, with a color depth K / S value of 11.1 and color fastness to washing, dry rubbing, and wet rubbing all at grade 2) produced using modern dyeing techniques, the K / S value of the fabric increased significantly after treatment using the methods described in Examples 1-1 to 1-7, demonstrating a remarkable color depth enhancement effect. Furthermore, the color fastness grades of the fabric increased from grade 2 to grade 3 or higher, meeting the requirements of relevant national standards, and the color fastness effect was also very significant. Examples 1-4 showed the best results.

[0028] Compared to the traditional ramie fabric finished product without color-fixing treatment (i.e., Fabric I, color depth K / S value of 11.8, color fastness to washing grade 3, color fastness to dry rubbing grade 2-3, color fastness to wet rubbing grade 2), after treatment by the methods used in Examples 2-1 and 2-2, the K / S value of the ramie fabric increased from 11.8, and the color-deepening effect was also significant; moreover, all color fastness grades were improved, and the color-fixing effect was also obvious.

[0029] The analysis results show that the method of the present invention has a significant effect on deepening and fixing the color of both yam-dyed silk (i.e., yam yarn, also known as fragrant cloud yarn) processed by traditional sun-drying process and yam pigment-dyed silk dyed by modern dyeing process.

[0030] Comparative Example 1-1: The oxidant in Example 1-1 was replaced with calcium hypochlorite, while the concentration remained unchanged (25 g / L). Other parameters were the same as in Example 1-1. The results are shown in Table 2.

[0031] The results showed that the K / S value of fabric II decreased from 11.1 to 9.5. This is because calcium ions complex with dioscorea tannin pigments, producing a light brown precipitate, which lightens the color of the fabric. Although hypochlorite ions in calcium hypochlorite have an oxidizing effect on dioscorea tannin pigments, the complexation reaction is faster than the oxidation reaction, and the resulting tannin-calcium complex prevents the oxidation reaction from occurring.

[0032] Comparative Examples 1-2: The oxidant in Examples 1-2 was replaced with hydrogen peroxide (concentration of 1.5%), and other parameters were the same as in Examples 1-2. The results are shown in Table 2.

[0033] The results showed that the K / S value of fabric II decreased significantly from 11.1 to 4.7, and the color fastness of all grades also decreased to grade 1-2. This indicates that hydrogen peroxide not only failed to deepen and fix the color of the fabric, but also had a bleaching effect. This may be because the oxidizing power of hydrogen peroxide is too strong, and the chemical reaction is too violent, destroying the structure of dioscorea pigment. This demonstrates that the choice of oxidant is crucial for deepening and fixing the color.

[0034] Comparative Examples 1-3: The oxidant in Example 1-1 was replaced with sodium chlorate, the concentration remained unchanged, and other parameters were the same as in Example 1-1. The results are shown in Table 2.

[0035] The results showed that the K / S value of fabric II decreased significantly from 11.1 to 6.2, and all color fastness properties decreased significantly. This indicates that sodium chlorate has a bleaching effect on dyed fabrics, similar to that of hydrogen peroxide.

[0036] Additionally, as is common knowledge, bromine-containing chemicals (such as sodium hypobromite) are not used in textile products, as they are highly corrosive to fabrics and harmful to the skin.

[0037] Comparative Example 2: The concentration of sodium hypochlorite aqueous solution used as oxidant in Examples 1-2 was reduced from 1.5 g / L to 0.5 g / L, while other parameters remained the same as in Examples 1-2. The results are shown in Table 2.

[0038] The results showed that the K / S value of fabric II only increased from 11.1 to 11.9. The wash fastness and dry rubbing fastness of the fabric were grade 2-3, an improvement of half a grade compared to before treatment, while the wet rubbing fastness remained at grade 2, showing no improvement. The color fastness of the dyed fabric treated under these conditions still did not meet the requirements of the relevant national standards (all color fastness grades should not be lower than 3). This indicates that the concentration of the oxidant used was low, and the effect of the color-fixing treatment was limited.

[0039] Comparative Example 3: The heat-drying reaction temperature of the fabric impregnated with oxidant in Examples 1-3 was replaced with 30°C instead of 42°C, while other parameters remained the same as in Examples 1-3. The results are shown in Table 2.

[0040] The results showed that the K / S value of fabric II increased only slightly from 11.1 to 12.1, indicating a very limited increase in color depth. The fabric's wash fastness was grade 3, and its dry and wet rubbing fastness was grades 2-3, showing a slight improvement in color fastness compared to before treatment. However, the resulting fabric still did not meet national standards. This demonstrates that a low reaction temperature resulted in limited color-fixing and deepening effects.

[0041] Comparative Example 4: The heat drying reaction time of the fabric impregnated with oxidant in Example 2-1 was replaced with 30 s instead of 2 min, while other parameters were the same as in Example 2-1. The results are shown in Table 2.

[0042] The results showed that the K / S value of fabric I only increased from 11.8 to 12.2, indicating a very limited increase in color depth. The fabric's wash fastness and dry rubbing fastness were grade 3, while its wet rubbing fastness was only grade 2-3. The color fastness grades of the treated fabric still did not meet the national standards. This demonstrates that a short heat treatment time is insufficient to achieve the desired color deepening and fixing effect.

[0043] Table 2

[0044] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A processing method for deepening and fixing the color of silk dyed with yam pigment, characterized in that... Includes the following steps: 1) Prepare an aqueous solution of oxidant with a concentration of 1~50 g / L, and use the aqueous solution of oxidant to finish the silk dyed with yam pigment, and then react at 40~100 ℃ for 1~10 min; to obtain the fabric after color-fixing treatment. 2) Wash and dry the fabric after the color-fixing treatment obtained in step 1).

2. The processing method for deepening and fixing the color of silk dyed with yam pigment according to claim 1, characterized in that: The finishing method is spraying or padding; When spraying, the dosage of the oxidant aqueous solution is: 200±20 mL / m 2 Fabrics; When rolling is used, the liquid content of the rolling strip should be controlled at 95%~105%.

3. The processing method for deepening and fixing the color of silk dyed with yam pigment according to claim 2, characterized in that: The oxidizing agent is at least one of sodium hypochlorite and sodium hypophosphite.

4. The processing method for deepening and fixing the color of silk dyed with yam pigment according to claim 3, characterized in that: The yam pigment-dyed silk includes Xiangyun yarn prepared by traditional techniques and yam pigment-dyed silk prepared by modern techniques.

5. A processing method for deepening and fixing the color of silk dyed with yam pigment according to any one of claims 1 to 4, characterized in that: In step 2): the fabric after the color-fixing treatment is thoroughly washed with pure water and then dried at 120±10℃ for 20±2s.

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