A dyeing method for industrial production of gaucho

Abstract

The present application belongs to the field of textile dyeing and finishing, and relates to a dyeing method for industrial preparation of gauze, comprising the following steps: 1) dip dyeing and hot baking of silk fabric (silk white blank); 2) performing color fixing treatment on the dip-dyed / hot-baked fabric by using an enzyme treatment solution; 3) repeatedly performing step 1) and step 2) on the fabric obtained in step 2) in sequence, and the number of repetitions is 1-3 times, to obtain a gauze dyeing product. The method is simple and easy to implement, has high efficiency, and controllable cost, and can be used for industrial preparation of gauze products.

Description

Technical Field

[0001] This invention belongs to the field of textile dyeing and finishing, and relates to an industrial method for dyeing ramie fabric. Background Technology

[0002] Langsha silk originated in the Lingnan region of my country and is one of China's national geographical indication products. It is a classic silk product deeply loved by domestic consumers. Langsha silk uses eco-friendly dyeing and finishing techniques, and the fabric has a unique double-sided color structure and excellent wearing performance.

[0003] The dyeing process for yam yarn is extremely complex, and traditionally it relies entirely on manual labor, proceeding in the following order: crushing yam tubers → preparing yam dye solution → dyeing the silk → sun exposure → repeating the dyeing / sun exposure process approximately 30 times → obtaining the sun-dried yam yarn product. In the preparation of yam yarn, the dyeing / sun exposure process is the most laborious and time-consuming, and is largely constrained by geographical and climatic conditions, making it difficult to achieve cross-regional and industrialized production. The product obtained after 30 dyeing / sun exposure processes is sun-dried yam yarn fabric, which can be directly used to make garments. The purpose of repeated dyeing / sun exposure is to allow the yam pigment to be deposited more firmly and extensively on the front side of the silk fabric (the sun-exposed side), creating a two-sided color effect (darker color on the front, lighter color on the back), and giving the finished fabric good colorfastness. Silk dyed repeatedly with yam pigment without sun exposure lacks a two-sided color effect, has very low colorfastness, and the pigment easily detaches from the fabric, making it difficult to meet the requirements of garments for two-sided colorfastness and colorfastness. This limitation makes the industrial production of yam yarn difficult, primarily due to the lack of color-fixing technology; industrial methods cannot achieve the color-fixing effect of sun exposure. Without a color-fixing process, simply relying on repeated dyeing / drying by machines makes it difficult to achieve continuous deposition of yam pigment on the fabric surface, because during dyeing, previously deposited pigment dissolves in the dye bath and detaches from the fabric. To address the dyeing and color-fixing issues in the preparation of yam yarn, the industry has adopted several alternative methods. These include using simulated sunlight (UV / IR lamps) to treat fabrics dyed with yam yarn pigment for color fixation (patents WO2018040887A1 and CN206157370U), pretreating silk fabrics with chemical auxiliaries (Research on Deepening Dyeing with Yam Yam Dye and its Imitation Xiangyun Yarn Dyeing and Finishing Process. Master's Thesis, Zhejiang Sci-Tech University, 2022), and treating with silicone resin after dyeing (CN202011557401.9). However, these methods have several drawbacks. For example, the first method involves complex equipment and high energy consumption, while the latter two use chemically synthesized auxiliaries, deviating from the concept of yam yarn as a purely natural, healthy, and environmentally friendly product, and failing to achieve the traditional double-sided color-changing effect of yam yarn, making them unacceptable to the industry and consumers. Therefore, the primary technical challenge for the industrial production of yam yarn is solving the dyeing and color-fixing problem during repeated dyeing processes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for dyeing silk fabrics with yam pigment using natural biological enzymes with high efficiency and high fastness.

[0005] To solve the above-mentioned technical problems, the present invention provides an industrial-scale dyeing method for preparing ramie silk, comprising the following steps:

[0006] 1) Dyeing and heating of silk fabric (silk blank):

[0007] Immersion dyeing: Immerse the silk fabric in a yam dye solution with a concentration of 5g / L to 20g / L and a temperature of 50±2℃ for 5±1s to obtain the dyed fabric.

[0008] Heat drying: The dyed fabric is heat dried using a heat drying device; during heat drying, the heating temperature of the upper side of the fabric (which becomes the right side after dyeing) is adjusted to 100℃~150℃ (preferably 115~150℃), and the heating temperature of the lower side of the fabric (which becomes the reverse side after dyeing) is 50℃~100℃ (preferably 62~100℃), and the temperature difference between the upper and lower sides of the fabric is ≥50℃; the heat drying time is 2±0.1min, to obtain the first dyed / heat dried fabric;

[0009] The first-dyeing / heat-drying fabric is then repeatedly dyed and heated; the process is repeated 4 times, that is, the total number of dyeing and heating steps is 5, resulting in a repeatedly dyed / heat-dried fabric.

[0010] Note: When drying, always place the fabric in the drying equipment with the same side facing the same direction, that is, always with the right side up and the wrong side down;

[0011] 2) Color fixing of dyed fabrics:

[0012] The biological enzyme preparation is dissolved in pure water to prepare an enzyme treatment solution with a concentration of 0.1 g / L to 1.5 g / L;

[0013] According to the enzyme treatment solution: repeatedly dyed / heat-dried fabric = 40% to 100% by weight, the enzyme treatment solution is sprayed onto the front side of the repeatedly dyed / heat-dried fabric using a spraying device, and then rolled into a tube. The color-fixing reaction is carried out for at least 5 hours under the environmental conditions of 35℃ to 45℃ and relative humidity of 85% to 100%.

[0014] Finally, heat-dry at 120±5℃ for 90±3s;

[0015] This indicates that the above color-fixing reaction time should generally not exceed 24 hours (i.e., it can be controlled to be 5 to 24 hours); otherwise, it will only lead to a decrease in production efficiency.

[0016] 3) Repeat steps 1) and 2) on the fabric obtained in step 2) for 1 to 3 times. That is, the total number of color-fixing treatments from step 1) dyeing / heat drying to step 2) is 2 to 4 times to obtain ramie silk (ramie silk dyed product).

[0017] An improvement to the dyeing method for the industrial preparation of ramie silk according to the present invention:

[0018] The biological enzyme preparation is catechol oxidase (also known as polyphenol oxidase or tyrosinase).

[0019] As a further improvement to the dyeing method for the industrial preparation of ramie silk of the present invention:

[0020] In step 1), the concentration of the yam dye solution is 11-20 g / L.

[0021] As a further improvement to the dyeing method for the industrial preparation of ramie silk of the present invention, in step 2):

[0022] The enzyme treatment solution has a mass concentration of 0.5 g / L to 1.0 g / L.

[0023] Enzyme treatment solution: 60-85% by weight of repeatedly dyed / heat-dried fabrics;

[0024] The color-fixing reaction temperature is 37–42℃, the relative humidity is 88–95%, and the color-fixing reaction time is 13–24 hours.

[0025] As a further improvement to the dyeing method for industrial preparation of ramie silk of the present invention, the number of repetitions in step 3) is 2 to 3 times, that is, the total number of times of dyeing / heat drying in step 1) to color fixing in step 2) is 3 to 4.

[0026] This invention addresses the shortcomings of repeated dyeing processes in the industrial production of yam silk products, such as complex equipment, high energy consumption, use of chemically synthesized products, unsatisfactory double-sided coloring effect, and low color fastness. It provides a method for dyeing silk with yam pigment using natural biological enzymes, achieving high efficiency and high fastness.

[0027] The principle of this invention is as follows: Under the action of catechol oxidase, dioscorea condensed tannin pigments with a catechol structure are polymerized or catalytically oxidized into quinones, reducing the water solubility of the dioscorea pigments. This improves the color fastness of the fabric dyed with dioscorea pigments and further achieves efficient dyeing based on good color fixation. Furthermore, the capillary effect generated by the temperature difference between the two sides of the fabric during heat drying (the side with higher temperature dries faster, and the side with lower temperature dries slower) causes more dioscorea pigments to migrate to the front side of the fabric, achieving a two-sided color effect.

[0028] Compared with other methods, the beneficial technical effects of this invention are:

[0029] Firstly, it does not use sunlight or simulated sunlight for color fixing, thus avoiding reliance on the natural environment and expensive simulated sunlight equipment. Furthermore, it avoids the problems of products that are not natural, environmentally friendly, or authentic, which are caused by the current industry's extensive use of chemical synthetic products for dyeing and color fixing.

[0030] Secondly, this method has high dyeing efficiency, requires fewer dyeing cycles, and produces products with good color fixation.

[0031] Third, this dyeing and fixing method is simple, energy-efficient, and easy to implement on conventional dyeing and finishing equipment.

[0032] In summary, this invention provides an industrial-scale dyeing method for preparing yam yarn. The silk fabric immersed in yam dye is dried under conditions of temperature difference, and the dyeing process is repeated a certain number of times using polyphenol oxidase. After multiple repetitions, the dyed fabric achieves high color depth, good color fastness, and a two-sided color effect. This method is simple, efficient, and cost-controllable, and can be used for the industrial-scale preparation of yam yarn products. Detailed Implementation

[0033] 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:

[0034] Fresh yam root tubers were crushed to a particle size of less than 5 mm. Water was added to the yam root tubers at a weight ratio of (1.4 ± 0.5): 1 and the mixture was extracted at 55 ± 5 °C with stirring for 0.5 to 3 hours. The extract was then filtered through a 50-mesh sieve to obtain yam dye solution, and the mass concentration of the dye solution was tested using a refractometer.

[0035] Generally speaking:

[0036] Extraction at 60℃ for 2 hours yielded a dioscorea stain solution with a concentration of approximately 18.8 g / L;

[0037] Extraction at 55℃ for 2 hours yielded a dioscorea stain solution with a concentration of approximately 15.2 g / L;

[0038] Extraction at 50℃ for 1 hour yielded a dioscorea stain solution with a concentration of approximately 11.0 g / L;

[0039] Extraction at 50℃ for 0.5 hours yielded a yam stain solution with a concentration of approximately 7.4 g / L.

[0040] Catechol oxidase (also known as polyphenol oxidase or tyrosinase, EC 1.10.3.1, activity 1000 U / mg) is available from Guangdong Mingtong Biotechnology Co., Ltd.; horseradish peroxidase (EC 1.11.1.7, activity 250 U / mg) and laccase (EC 1.10.3.2, activity 50 U / mg) are available from Hangzhou Mike Chemical Instrument Co., Ltd.

[0041] All the following examples use the same raw silk fabric, spun by electric spinning, with a weight of 130g / m². 3 .

[0042] Example 1: A dyeing method for industrially preparing ramie silk, comprising the following steps:

[0043] 1) Dyeing and heat treatment of silk fabrics:

[0044] Immersion dyeing: Immerse the raw silk fabric in a yam dye solution with a mass concentration of 15.2 g / L and a temperature of 50±2℃ for 5 seconds, then remove it to obtain the dyed fabric.

[0045] Heat drying: Place the dyed fabric into a heat drying device, adjust the heating temperature of the upper side of the fabric (which becomes the right side after dyeing) to 130℃, and adjust the heating temperature of the lower side of the fabric (which becomes the reverse side after dyeing) to 75℃, that is, the temperature difference between the upper side and the lower side of the fabric is 55℃. Heat dry the fabric for 2 minutes under the above heating conditions to obtain the first dyed / heat dried fabric.

[0046] The first-dyeing / heat-drying fabric is then subjected to four more dyeing-heat-drying processes; that is, the total number of dyeing-heat-drying processes is five, resulting in a dyed / heat-drying fabric that has been repeatedly dyed five times.

[0047] Note: When drying, always place the fabric in the drying equipment with the same side facing the same direction, that is, always with the right side up and the wrong side down.

[0048] 2) Color fixing of dyed fabrics:

[0049] Catechol oxidase was dissolved in pure water to prepare an enzyme treatment solution with a concentration of 0.7 g / L.

[0050] According to the enzyme treatment solution: repeatedly dyed / heat-dried fabric = 60% by weight, the enzyme treatment solution was sprayed onto the front side of the repeatedly dyed / heat-dried fabric using a spraying device, and then rolled into a tube and subjected to a color-fixing reaction for 16 hours under an environment of 40°C and 95% relative humidity.

[0051] Finally, bake at 120℃ for 90 seconds;

[0052] 3) Repeat steps 1) and 2) on the fabric obtained in step 2) three times, that is, the total number of color-fixing treatments from step 1) dyeing / heat drying to step 2) is 4 times, to obtain the dyed silk fabric product.

[0053] Examples 2 to 4 are obtained by changing the process parameters (specifically as shown in Table 1 below) compared to Example 1, while the rest are the same as Example 1; thus, Examples 2 to 4 are obtained accordingly.

[0054] Table 1

[0055]

[0056]

[0057] The dyed silk fabrics obtained in Examples 1 to 4 were tested and analyzed:

[0058] The color depth (K / S value) of the front and back sides of the ramie-dyed product was tested using a conventional spectrophotometer; the color fastness to washing was tested using AATCC 61-2003 "Household and Commercial Washing Fastness: Rapid Method"; and the color fastness to dry and wet rubbing on the front side of the fabric was tested using GB / T 3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Rubbing". The test results are shown in Table 2.

[0059] Table 2

[0060]

[0061] turn out:

[0062] The K / S values ​​of the front and back sides of the ramie-dyed fabric obtained in Example 1 are 8.3 and 3.4, respectively, exhibiting a clear two-sided color difference effect, and the color depth of the front side reaches the color depth of traditional sun-dried ramie fabrics. The wash fastness of this ramie-dyed fabric is grade 4-5; the dry rubbing fastness and wet rubbing fastness are grade 3-4 and grade 3, respectively, reaching or even exceeding the color fastness of traditional sun-dried ramie fabrics (wash fastness is generally grade 4, dry rubbing fastness is generally grade 3-4, and wet rubbing fastness is generally grade 2-3).

[0063] The ramie-dyed fabric obtained in Example 2 has K / S values ​​of 8.1 and 3.2 on the front and back sides, respectively, exhibiting a clear two-sided color difference effect, and the color depth on the front side reaches the color depth of traditional sun-dried ramie fabrics. The ramie-dyed fabric has a wash fastness of 4-5; its dry rubbing and wet rubbing fastness are 4 and 3, respectively, reaching or even exceeding the color fastness of traditional sun-dried ramie fabrics.

[0064] The ramie-dyed fabric obtained in Example 3 has K / S values ​​of 7.8 and 3.1 on the front and back sides, respectively, exhibiting a clear two-sided color difference effect, and the color depth on the front side reaches the color depth of traditional sun-dried ramie fabrics. The ramie-dyed fabric has a wash fastness of 4-5; its dry rubbing fastness and wet rubbing fastness are 3-4 and 3, respectively, reaching or even exceeding the color fastness of traditional sun-dried ramie fabrics.

[0065] The ramie-dyed fabric obtained in Example 4 has K / S values ​​of 6.5 and 3.0 on the front and back sides, respectively, exhibiting a clear two-sided color difference effect, and the color depth on the front side reaches the color depth of traditional sun-dried ramie fabrics. The ramie-dyed fabric has a wash fastness of grade 4; its dry rubbing fastness and wet rubbing fastness are grades 3-4 and 3, respectively, reaching the color fastness of traditional sun-dried ramie fabrics.

[0066] Therefore, the ramie dyed fabric obtained by the processing method of the present invention has two different colors on both sides and good color fastness.

[0067] Comparative Example 1: Compared to Example 2, the concentration of the yam dye solution was changed to 4.2 g / L; the rest was the same as in Example 2.

[0068] Comparative Example 2: Compared to Example 2, the heating temperature on the front side of the fabric was changed to 130°C and the heating temperature on the reverse side of the fabric was changed to 110°C, that is, the temperature difference between the front and reverse sides of the fabric was changed to 20°C; the rest is the same as Example 2.

[0069] Comparative Example 3: Compared to Example 2, the concentration of catechol oxidase was changed to 0.05 g / L, and the rest was the same as in Example 2.

[0070] Comparative Example 4: Compared to Example 2, the color-fixing reaction temperature was changed to 30°C, and the rest was the same as Example 2.

[0071] Comparative Example 5: Compared to Example 2, the relative humidity of the color-fixing reaction was changed to 75%, and the rest was the same as in Example 2.

[0072] Comparative Example 6: Compared to Example 2, the color-fixing reaction time was changed to 3.5 hours, and the rest was the same as Example 2.

[0073] Comparative Example 7, referring to patent CN202011557401.9 (natural dyeing method using yam), steps (1) to (3) in Example 1 of that patent were performed to obtain yam-dyed fabric.

[0074] Comparative Example 8: Compared to Example 2, the catechol oxidase treatment solution was replaced with a horseradish peroxidase treatment solution, while the concentration and amount of the treatment solution remained unchanged, and the rest were the same as in Example 2.

[0075] Comparative Example 9: Compared to Example 2, the catechol oxidase treatment solution was replaced with laccase treatment solution, while the concentration and amount of the treatment solution remained unchanged, and the rest were the same as in Example 2.

[0076] The dyed silk products obtained from Comparative Examples 1 to 9 were tested and analyzed (using the same testing and analysis methods as above). The test results are shown in Table 3 below.

[0077] Table 3

[0078]

[0079] In Comparative Example 1, the concentration of the yam dye solution did not meet the requirements of this invention. The resulting dyed fabric had a K / S value of only 4.1 on the front side, significantly lower than the color depth of the front side of traditional sun-dried yam fabric (K / S value above 6.0). The front side color was too light, noticeably different from the appearance of traditional sun-dried yam fabric. Therefore, if the concentration of the yam dye used is too low, less yam pigment is deposited on the fabric surface, resulting in a lighter fabric color and ultimately failing to obtain a yam yarn dyed product similar to traditional sun-dried yam fabric.

[0080] In Comparative Example 2, the temperature difference between the front and back sides of the fabric did not meet the requirements of this invention. The resulting dyed fabric had a K / S value of 6.8 on the front and 6.4 on the back, with a difference of only 0.4 between the two sides. This is far less than the color depth difference between the front and back sides of traditional sun-dried yam fabric (K / S value difference greater than 3.0). The resulting dyed fabric did not exhibit a significant two-sided color difference effect, clearly differing from the appearance characteristics of traditional sun-dried yam fabric. This is because the temperature difference between the front and back sides is small, the drying rates on both sides are similar, the capillary effect is not significant, and the amount of yam pigment migrating to the front side of the fabric is small. Therefore, if the drying temperature and temperature difference between the front and back sides of the fabric do not meet the requirements of this invention, a yam yarn dyed product similar to traditional sun-dried yam fabric cannot be obtained.

[0081] In Comparative Example 3, the concentration of catechol oxidase did not meet the requirements of this invention. The resulting dyed fabric had a K / S value of 5.3 on the front and 2.1 on the back, indicating that the color on the front was too light and significantly different from the appearance of traditional sun-dried hyacinth fabrics. The dyed fabric exhibited a water wash fastness of grade 3, a dry rubbing fastness of grade 2-3, and a wet rubbing fastness of grade 2, which was significantly worse than traditional sun-dried hyacinth fabrics. The resulting dyed fabric had significantly lower color depth and color fastness than sun-dried hyacinth fabrics prepared using traditional processes. This is because the concentration of catechol oxidase was low, resulting in only a portion of the hyacinth pigment being polymerized or catalytically oxidized into quinones. Therefore, if the concentration of catechol oxidase used is too low, a hyacinth yarn dyed product with good color depth and color fastness cannot be obtained.

[0082] In Comparative Example 4, the fixation reaction temperature of catechol oxidase was significantly lower than the requirements of this invention. The resulting dyed fabric had a K / S value of 5.7 on the front and 2.8 on the back, with a lighter color on the front, significantly different from the appearance of traditional sun-dried hyacinth fabrics. The color fastness to washing was grade 3, the color fastness to dry rubbing was grade 2-3, and the color fastness to wet rubbing was grade 2, significantly worse than traditional sun-dried hyacinth fabrics. The resulting dyed fabric had significantly lower color depth and color fastness than sun-dried hyacinth fabrics prepared by traditional processes. This is because the optimal temperature range for catechol oxidase activity is 35-45℃. If the temperature is too low or too high, the activity of catechol oxidase will be inhibited, reducing the catalytic effect and adversely affecting the catalytic reaction of hyacinth pigment. Therefore, if the catalytic reaction temperature (fixation reaction temperature) of the catechol oxidase used is too low, a dyed hyacinth yarn product with good color depth and color fastness cannot be obtained.

[0083] In Comparative Example 5, the relative humidity of the catechol oxidase fixation reaction conditions was significantly lower than the requirements of this invention. The resulting dyed fabric had a K / S value of 5.6 on the front and 2.5 on the back, with a lighter color on the front, significantly different from the appearance of traditional sun-dried hyacinth fabrics. The color fastness to washing was grade 3-4, the color fastness to dry rubbing was grade 3, and the color fastness to wet rubbing was grade 2, essentially half a grade lower than traditional sun-dried hyacinth fabrics. The resulting dyed fabric had significantly worse color depth and color fastness than sun-dried hyacinth fabrics prepared by traditional processes. This is because the lower ambient humidity caused the enzyme solution on the fabric to evaporate easily, the fabric surface to dry easily, and the activity of catechol oxidase to decrease, affecting the catalytic reaction effect of catechol oxidase and resulting in a significant reduction in the amount of hyacinth pigment reacting on the fabric surface. Therefore, if the relative humidity conditions of the catechol oxidase used are too low, a dyed hyacinth fabric product with good color depth and color fastness cannot be obtained.

[0084] In Comparative Example 6, the fixation reaction time of catechol oxidase was significantly shorter than required by this invention. The resulting dyed fabric had a K / S value of 5.2 on the front and 2.1 on the back, with a lighter color on the front, significantly different from the appearance of traditional sun-dried hyacinth fabrics. The color fastness to washing was grade 2-3, the color fastness to dry rubbing was grade 2, and the color fastness to wet rubbing was grade 2, significantly worse than traditional sun-dried hyacinth fabrics. The resulting dyed fabric had significantly lower color depth and color fastness than sun-dried hyacinth fabrics prepared by traditional processes. This is because the reaction time of catechol oxidase catalyzing the hyacinth pigment was too short, resulting in only a small amount of hyacinth pigment reacting on the fabric surface. Therefore, if the catalytic reaction time of the catechol oxidase used is too short, a dyed hyacinth yarn product with good color depth and color fastness cannot be obtained.

[0085] Comparative Example 7: The obtained dyed fabric has a K / S value of 6.7 on both the front and back sides, with no color difference between the two sides, significantly different from the two-sided color difference effect of traditional sun-dried yam fabrics. The dyed fabric has a water washing color fastness of 1-2, a dry rubbing color fastness of 1, and a wet rubbing color fastness of 1, indicating very poor color fastness. This is because the method lacks the crucial color fixation step. Even with 30 repeated immersion / heat drying processes, the dyed fabric cannot achieve good color fastness. This is because heat drying alone cannot firmly bond the yam pigment to the fabric surface. Therefore, a color fixation step is essential for repeated dyeing.

[0086] Comparative Example 8: The obtained dyed fabric had a K / S value of 5.2 on the front and 2.6 on the back. The color on the front was significantly lighter than that of the ramie dyed product obtained in Example 2, and also less deep than that of traditional sun-dried ramie fabric. The dyed fabric exhibited poor colorfastness to washing (grade 2), dry rubbing (grade 2), and wet rubbing (grade 1). This is because, although the horseradish peroxidase used for color fixation has been reported in the literature to catalyze the polymerization of phenolic substances such as phenol, it may actually exhibit some selectivity in its catalysis of the substrate. Furthermore, it has low catalytic activity towards bisphenol-containing substances like ramie tannin pigment, thus failing to achieve a color-fixing effect. Therefore, the use of catechol oxidase in the color-fixing step is crucial.

[0087] Comparative Example 9: The K / S value of the obtained dyed fabric on the front side was 5.9, and the K / S value on the back side was 3.0. The color depth of the fabric on the front side was significantly different from that of the ramie dyed product obtained in Example 2, and also inferior to traditional sun-dried ramie fabric. The color fastness to washing of the dyed fabric was grade 3, the color fastness to dry rubbing was grade 2-3, and the color fastness to wet rubbing was grade 2, indicating relatively poor color fastness. This is because the laccase activity (the laccase activity used in this example was 50 U / mg, which is already a relatively high activity among commercially available laccase products) is much lower than that of catechol oxidase. Under the same enzyme concentration conditions, the effect of catalyzing diosgenin pigments with a catechol structure is significantly less than that of catechol oxidase. Although it also achieved a relatively obvious color-fixing effect, it was significantly inferior to the color-fixing effect of catechol oxidase. Therefore, it is evident that catechol oxidase reagent is indispensable in the color-fixing step during repeated dyeing.

[0088] 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 dyeing method for industrially preparing ramie silk, characterized in that... Includes the following steps: 1) Dyeing and heat treatment of silk fabrics: Immersion dyeing: Immerse the silk fabric in a yam dyeing solution with a concentration of 5g / L~20g / L and a temperature of 50±2℃ for 5±1s to obtain the dyed fabric. Heat drying: The dyed fabric is heat dried using a heat drying device; during heat drying, the heating temperature of the upper side of the fabric is adjusted to 100℃~150℃, the heating temperature of the lower side of the fabric is 50℃~100℃, and the temperature difference between the upper and lower sides of the fabric is ≥50℃; the heat drying time is 2 ±0.1min, and the first dyed / heat dried fabric is obtained. Repeat the dyeing-drying process on the fabric that was first dipped / heat-dried; The process is repeated four times to obtain a repeatedly dyed / heat-dried fabric. 2) Color fixing of dyed fabrics: The biological enzyme preparation was dissolved in pure water to prepare an enzyme treatment solution with a concentration of 0.5 g / L to 1.0 g / L; the biological enzyme preparation was catechol oxidase. According to the weight ratio of enzyme treatment solution to repeatedly dyed / heat-dried fabric = 40% to 100%, the enzyme treatment solution is sprayed onto the front side of the repeatedly dyed / heat-dried fabric using a spraying device, and then rolled into a tube. The color-fixing reaction is carried out for 13 to 24 hours under the environmental conditions of 37 to 42°C and 88 to 95% relative humidity. Finally, heat-dry at 120±5℃ for 90±3s; 3) Repeat steps 1) and 2) on the fabric obtained in step 2) 1 to 3 times to obtain lan shawl.

2. The dyeing method for industrial-scale preparation of ramie silk according to claim 1, characterized in that... In step 1), the concentration of the yam stain solution is 11~20 g / L.

3. The dyeing method for industrial-scale preparation of ramie silk according to claim 2, characterized in that... In step 2): Enzyme treatment solution: 60~85% by weight of repeatedly dyed / heat-dried fabrics.

4. The industrial-scale dyeing method for preparing ramie silk according to any one of claims 1 to 3, characterized in that: Step 3) is repeated 2 to 3 times.

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