Lyocell colorful fabric based on vegetable dye dyeing

Abstract

The invention provides a lyocell colorful fabric based on vegetable dye dyeing, and belongs to the technical field of textile printing and dyeing. The colorful fabric is obtained by dyeing with a vegetable dye and is woven from the following silk yarns: 30-40% of lyocell, 20-30% of mulberry silk, 15-20% of polyamide, 10-15% of PBS, 0-10% of acetate and 0-10% of polyester, and the organization structure of the colorful fabric is at least composed of more than five same silk yarn block surfaces or lines. The fabric not only has rich and bright colors, but also has the advantages of three-dimensional patterns, distinct gradation, simple process and the like.

Description

Technical Field

[0001] This application relates to a lyocell iridescent fabric dyed with plant dyes, belonging to the field of textile printing and dyeing technology. Background Technology

[0002] Textile printing and dyeing is a vital industry for people's livelihood. The quality of textiles directly affects wearing comfort and health. The drawbacks of synthetic dyes have attracted great attention from governments and experts worldwide. Solutions have been limited to restricting wastewater discharge from the printing and dyeing industry, banning the use of certain dyes, and limiting the heavy metal and formaldehyde content of textiles. However, these measures cannot fundamentally solve the problem of synthetic dyes seriously polluting the environment and harming human health. With increasing environmental awareness, a new trend of green consumption themed around returning to nature has emerged among consumers worldwide. Non-toxic, harmless, biodegradable, and renewable plant dyes are gradually becoming more widely known.

[0003] Plant dyes are natural coloring substances extracted from the roots, stems, leaves, flowers, and fruits of plants in nature. The extraction process does not involve fossil fuel-related chemicals and has the characteristics of wide availability, good environmental compatibility, biodegradability, and renewable raw materials. Not only do they pose minimal harm to the environment and human body, but they also have health benefits such as anti-oxidation, antibacterial, and UV protection. At the same time, the dyed fabrics have a natural, soft, and elegant color. These characteristics give them advantages that synthetic dyes cannot surpass, and the development prospects of dyeing will become increasingly broad.

[0004] Current research on the application of plant dyes in dyeing is extensive, but the dyeing effects tend to be rather limited. Textiles with multiple colors and patterns are more visually striking and appealing to consumers than those with a single color. To achieve fabric printing and dyeing effects with multiple colors and patterns, the following methods are typically used:

[0005] First, multi-color plant dye printing is used. However, when using screen printing, common multi-color printing facilities such as rollers and screen printing require plate making, which is costly. During the multi-color process, the printing paste needs to be screened, and the compatibility of the mordant and paste, as well as the stability of the paste, must be considered. Printing requires several processes such as overprinting, drying, steaming, and washing with different plant dye pastes, making the process complex and time-consuming. Digital printing, on the other hand, requires preparing stable inks from several colors of plant dyes. High requirements are placed on the purity, solubility, color intensity, and compatibility between the different colors of plant dyes. For example, CN103952922B prepares digital printing ink from reddish-brown plant dye extracted from natural tea tree fruit, viscosity modifiers, co-solvent polyether polyols, surface tension modifiers (polyether-modified polydimethylsiloxane surfactants), pH adjusters, humectants, and bactericides (benzisothiazolinone); CN105 Digital printing ink 586791A is composed of a reddish-brown pigment extracted from Isatis indigotica root, viscosity modifiers, cosolvents, surface tension modifiers, pH adjusters, humectants, bactericides, fixing agents, antioxidants, mildew inhibitors, and deionized water. CN106245356B first forms a black natural dye from tannic acid, hematoxylin, and ferrous sulfate, then combines the black natural dye raw materials, surfactants, hygroscopic cosolvents, rheology modifiers, preservatives, pH adjusters, and deionized water to create a water-based black natural dye inkjet printing ink. While these methods use a large amount of chemical auxiliaries to improve ink performance during preparation and printing, they still suffer from problems such as instability, unsatisfactory color fastness, inability to achieve deep colors, and limited color gamut in practical applications. Furthermore, no mature plant-based dye ink products are currently available on the market.

[0006] Secondly, a method using deepening agents (cationic auxiliaries, natural proteins, etc.) and different mordants (including partial and complete treatment) combined with plant dyeing or printing is employed. Similar to multi-color plant dye printing, this method suffers from complex processes, long processing times, and low efficiency, and is prone to staining during dyeing and washing. For example, CN108797157B uses cationic modification treatment, followed by natural dyeing, and finally printing with one or more combinations of mordants to obtain two-color printed fabrics. This method suffers from the problem of mutual interference between multiple mordants. CN108797157B involves plasma pretreatment followed by digital inkjet printing of an alkaline protein paste made of lime, soybean flour, and water, followed by sappanwood dyeing, mordant treatment, and ultrasonic washing. This method achieves a three-color printing effect on the fabric using only one natural dye. However, digital printing has high requirements for the particle size, viscosity, uniformity, and stability of the inkjet paste, which is difficult to meet with lime, soybean flour, and water, making the alkaline protein paste method difficult to implement.

[0007] Third, special techniques such as resist dyeing (tie-dye, batik, etc.), discharge dyeing, and heat transfer printing of plant flowers and leaves are used to dye with multi-colored plant dyes. Examples include CN1417400A, CN1056327A, and CN119777176A. These special techniques require multiple resist treatments such as tying or wax painting, dyeing, steaming, and washing. Furthermore, the processes of tying flowers or painting with wax and arranging plants are primarily manual, resulting in a large workload, low efficiency, interference between multiple colors, poor reproducibility of some patterns, and issues with wax pollution and recycling in batik. Summary of the Invention

[0008] In view of this, this application provides a Lyocell iridescent fabric based on plant dyeing, which can not only present a rich variety of colors, but also has large hue differences, three-dimensional patterns, distinct layers, and varied styles. It has the advantages of short preparation process, high production efficiency, good reproducibility, and green environmental protection, and can be used for industrial applications.

[0009] Specifically, this application is implemented through the following scheme:

[0010] A lyocell iridescent fabric based on plant dye dyeing, wherein the iridescent fabric is obtained by dyeing with plant dyes and woven from the following yarns:

[0011]

[0012]

[0013] The structure of the iridescent fabric consists of at least five or more blocks or lines of the same type of yarn.

[0014] In this application, Lyocell fiber is an environmentally friendly regenerated cellulose fiber with excellent hydrophilicity, moisture absorption, comfort, and drape, providing a good feel and wearing comfort for vibrant fabrics. Preferably, it is either filament or cross-linked Lyocell. Silk is a natural protein fiber formed from the coagulated silk fluid secreted by mature silkworms during cocooning, possessing advantages such as good luster, softness, breathability, strong moisture absorption, and wearing comfort. Plant dyes have excellent dyeing performance on silk, allowing for the selection of refined silk, raw silk, or spun silk according to the style requirements of the vibrant fabric. Polyamide (PA) fiber has advantages such as high strength and good abrasion resistance. This invention preferably uses bio-based polyamide fibers, such as PA56, PA54, and PA66. While enriching the colors, this invention addresses the issue of fabrics being too soft due to high Lyocell and silk content, providing a certain degree of structure and crispness, making the fabric less prone to wrinkles and easier to care for. PBS refers to polybutylene succinate fiber, which has good biocompatibility and bioabsorption. It can be completely biodegraded into carbon dioxide and water in 6 months via composting, is relatively inexpensive, and has excellent mechanical properties. Bio-based PBS fibers are preferred. Acetate combines the characteristics of natural and synthetic fibers, possessing both the feel and luster of silk, as well as smoothness, stiffness, and resistance to mildew and moths. Polyester fiber's greatest advantage is its excellent wrinkle resistance and shape retention, along with high strength and elastic recovery. The above fibers have different dyeing properties; combined with the requirements of the weave structure, after dyeing with plant dyes, the fabric can be given a vibrant color effect.

[0015] Furthermore, as a preferred option:

[0016] The weave structure is plain weave, twill weave, double warp, double weft, or double layer, etc.

[0017] The plant dyeing process includes two steps: dyeing with plant indigo dye and dyeing with other plant dyes. The other plant dyes are extracts of at least one of the following: rhubarb, scutellaria barbata, phellodendron amurense, scutellaria baicalensis, polygonum cuspidatum, arborvitae leaf, safflower, red yeast rice, fleeceflower root, cat's whiskers, purple-leaf plum, euphorbia humifusa, cornus officinalis, buckthorn, and grape skin.

[0018] The two steps of dyeing with plant dyes mentioned above only represent the necessary steps in the method of this invention; the order of the two steps is not particularly limited. Different components in the fabric of this invention exhibit different dyeing properties. Rhubarb has excellent dyeing effects on polyamide and mulberry silk; alum produces a golden yellow; ferrous sulfate produces an autumnal yellow on polyamide and a dark gray-green on mulberry silk; PBS dyeing is also good, producing a greenish-yellow (alum) and green; the color is relatively lighter on lyocell, acetate, and polyester. Phellodendron bark and alum can produce a bright yellow on mulberry silk and polyamide, a light yellow on lyocell and PBS, and essentially colorless on polyester; with ferrous sulfate, it can produce green on mulberry silk and polyamide, a light yellow-green on lyocell and PBS, and essentially colorless on polyester. Red yeast rice and alum can dye polyamide and mulberry silk red, PBS and acetate pink, and have virtually no color on lyocell and PET polyester. Qinglongyi is the dried green husk of walnuts. When combined with alum on polyamide, it appears brownish-red; on silk, it appears yellowish-brown; on PBS and ester, it appears tea-colored; and on lyocell, it appears light tea-colored. When combined with ferrous sulfate, it appears brownish-red on polyamide, brownish-brown on silk, and light gray with different colors on PBS, ester, and lyocell.

[0019] The dyeing process of the plant indigo dye is as follows: water intake – fabric intake – heating to 50-80℃ and running for 3-5 cycles at a heating rate of 1-3℃ / min – drainage – water addition at a liquor ratio of 1:5-1:20 – adding appropriate amounts of alkaline and reducing substances and running for 3-5 cycles – adding pre-reduced plant indigo – dyeing at room temperature for 5-20 cycles at a pH of 9-11.5, during which alkaline and reducing substances are added according to the pH and reduction potential – draining – water oxidation for 4-6 cycles – water washing for 2-4 cycles – acid washing for 4-6 cycles – adding deoxygenating enzyme and water washing for 4-6 cycles – dehydration (– drying).

[0020] More preferably:

[0021] The pre-reduced plant indigo refers to:

[0022] Step 1: Add an appropriate amount of alcohol and water to the indigo plant and stir until there is no dry powder.

[0023] Step 2: Dissolve the alkaline and reducing substances separately in an appropriate amount of water, then add them to Step 1, stir well, let stand for 30-60 minutes, control the pH value to be 10-11.5, and the reduction potential to be higher than -760mV.

[0024] The plant-based indigo is extracted from indigo plants such as woad, knotweed, and woad. The stems and leaves of these plants contain indigo glycosides, from which indigo dye can be extracted, making it a vat dye in the indigo family. Plant-based indigo with fewer impurities after purification is preferred to avoid defects caused by impurities and to facilitate uniform dyeing.

[0025] The alkaline substance is at least one of caustic soda, soda ash, and baking soda, and the reducing substance is at least one of sodium hydrosulfite and thiourea dioxide.

[0026] The purpose of heating the fabric after it is fed into the dyeing process is to fully wet the fabric, which facilitates the uniform application of dyes in subsequent dyeing. The addition of alkaline and reducing substances before dyeing is to remove oxygen from the working solution and the fabric, preventing the plant indigo from being oxidized after addition, and preparing the conditions for dyeing. The plant indigo pre-reduction solution can be added in multiple stages depending on the quantity, at least in two stages, to reduce color difference between the beginning and end. The pH value of room temperature dyeing is 9-10, which can reduce the damage of excessive alkalinity to silk, PBS, and cross-linked Lyocell, while improving the dyeing performance of plant indigo and enhancing the color difference after subsequent dyeing.

[0027] The influent oxidation is carried out by air oxidation. To ensure sufficient oxidation, the oxidation rate can be 1-5 g / L H2O2 depending on the depth and bath ratio.

[0028] The deoxygenase is a biological enzyme preparation that can remove residual H2O2, thus avoiding interference with subsequent dyeing with other plant dyes.

[0029] The dyeing process for plant dyes other than indigo is as follows: water intake – fabric intake – heating to 50-80℃ (heating is not required if it is a second dyeing), run for 2-5 cycles – add plant dye, heat to 40-60℃ and run for 10-20 cycles, control pH value to 2-5 – add mordant, run for 10-20 cycles at 40-60℃ – drain – wash with warm water at 40-60℃ – wash with cold water – dehydrate (– dry).

[0030] More preferably:

[0031] When adding other plant dyes and mordants in the above process, they can be added in multiple stages according to the amount used, at least in two stages, to reduce the color difference between the beginning and end.

[0032] The preferred pH value for the dyeing process is 3.5±1.

[0033] The preferred dyeing process involves a staged heating and holding process: first, the temperature is raised to 40℃ and run for 2-4 stages, then raised to 50℃ and run for 4-6 stages, and finally raised to 60℃ and run for 6-10 stages.

[0034] When staining at 40–60°C, the heating rate is 0.5–1.5°C / min.

[0035] The other plant dyes are selected from two or more of the following: rhubarb, purslane, phellodendron bark, scutellaria barbata, polygonum cuspidatum, arborvitae leaf, safflower, red yeast rice, fleeceflower root, cat's whiskers, purple-leaf plum, euphorbia humifusa, cornelian cherry, buckthorn, and grape skin.

[0036] The mordant is at least one of alum, ferrous sulfate, or cobalt sulfate.

[0037] The drying temperature is 110–160℃, preferably 120–140℃; the time is 30–90 seconds, which reduces the damage to plant dyes and some components of the fabric caused by prolonged high temperature.

[0038] The beneficial effects of the present invention are as follows:

[0039] 1. The lyocell iridescent fabric based on plant dyeing of the present invention has rich and bright colors, making the patterns more three-dimensional and layered. Different yarns can be selected according to actual needs to obtain iridescent fabrics of various styles, and the application range is wide.

[0040] 2. The Lyocell iridescent fabric based on plant dyeing of the present invention can be obtained by dyeing with equipment. The dyeing process is simple, and the color is uniform and the color fastness is excellent. It has the advantages of short preparation process, high production efficiency and good reproducibility, and is suitable for industrial application.

[0041] 3. The Lyocell iridescent fabric based on plant dyeing of the present invention is basically woven from natural and renewable silk threads; its dyeing process does not add any fossil energy synthetic organic auxiliaries, which is in line with the natural and environmentally friendly characteristics of plant dyeing, and is of great significance in the current context of global attention to green, low-carbon, environmental protection and sustainable development. Detailed Implementation

[0042] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the technical solutions of this application will be further described in detail below with reference to specific examples in the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit the technical solutions of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Example 1

[0044] This embodiment determines the proportion of yarns in each component of the fabric and adopts a plain weave checkered pattern structure. The composition of the Lyocell iridescent fabric is shown in Table 1.

[0045] Table 1: Composition of Plain Check Pattern Lyocell Iridescent Fabric

[0046] Composed of silk threads Example 1-1 Examples 1-2 Examples 1-3 Examples 1-4 80D Lyocell Filament 40 30 30 20 Refined mulberry silk filaments 25 30 30 30 70D Semi-photobio-based PA56 15 20 15 25 75D Bio-based PBS 15 10 10 5 100D acetate filament 0 10 7 5 60S PET yarn 10 0 8 15

[0047] Dyeing process:

[0048] Staining 1: Plant-based indigo staining

[0049] Pre-reduction of plant indigo: First, add 50mL of alcohol and 500g of water to 500g of plant indigo and stir until there is no dry powder. Then add 6.5L of water. Next, dissolve 50g of NaOH and 125g of sodium hydrosulfite in 3L of water and add them to the mixture. Stir well and let stand for 60 minutes. The pH value is 10.7 and the reduction potential is -813mV.

[0050] Dyeing vat water intake (100L) – Fabric intake (82m, 10kg) – Heating and running for 4 cycles (2℃ / min, 60℃) – Draining – Adding water (70L) – Adding a solution of 7g NaOH, 15g sodium hydrosulfite, and 300mL water and running for 4 cycles – Adding pre-reduced plant indigo solution in 2 cycles (filtered twice through a 200-mesh screen) – Dyeing at room temperature for 10 cycles (adding NaOH and sodium hydrosulfite according to pH and reduction potential) – Draining – Air oxidation for 4 cycles – Water intake (H2O2 2mL / L) and running for 4 cycles – Water washing for 4 cycles – Acid washing (acetic acid added in small amounts multiple times according to pH) for 4 cycles – Water washing for 4 cycles (deoxygenase 1mL / L).

[0051] Staining 2: Overcoloring of extracts from Phellodendron amurense and Cochineal

[0052] Water intake (70L) – Add plant dyes (10L each of Phellodendron bark extract and cochineal extract, filtered twice through a 200-mesh screen, pH 4.2) in 4 stages – Heat to 40℃ (1℃ / min) and run for 4 stages – Increase temperature to 50℃ (1℃ / min) and run for 6 stages – Increase temperature to 60℃ (1℃ / min) and run for 8 stages – Cool down to 40℃ and add mordant (150g alum, 4L hot water) in 2 stages – Heat to 40℃ (1℃ / min, pH 2.8) and run for 4 stages – Increase temperature to 50℃ (1℃ / min) and run for 6 stages – Increase temperature to 60℃ (1℃ / min) and run for 8 stages – Drain – Wash with warm water for 6 stages (60℃) – Wash with cold water for 4 stages – Dehydrate – Dry (130℃ × 60s).

[0053] Fabric performance testing after dyeing:

[0054] The Lyocell iridescent fabrics, each component listed in Table 1 and dyed with plant dyes, were tested separately. For color correlation testing, the fabric samples were placed in a standard light source color matching box using a D65 light source, with the light shining perpendicularly onto the fabric sample and observed at a 45° angle. Hue was categorized into nine colors: red, orange, yellow, green, blue, purple, blackish-gray, white, and brownish-red. Color differences were assessed based on a combination of hue, depth, and saturation, categorized into five levels with nine grades, ranging from level 1 to level 5. The feel / style was evaluated using multiple judges' results. Color fastness to rubbing, water, and perspiration was tested and rated according to national standards GB / T 3920-2024, GB / T5713-2013, and GB / T 3922-2013, respectively. The test results are shown in Table 2.

[0055] Table 2: Influence of different fabric compositions on the color and properties of dyed plain weave checkered Lyocell iridescent fabric

[0056]

[0057] As shown in Table 2, when the values ​​of each component fall within the given range (i.e., "Lyocell 30-40%, silk 20-30%, polyamide 15-20%, PBS 10-15%, acetate 0-10%, polyester 0-10%), the hand feel is soft and crisp without the addition of a hand-feel finishing agent (as in Examples 1-1, 1-2, and 1-3). However, when the proportions of each component fall outside the given range, such as in Examples 1-4, the hand feel is slightly worse, mainly because the content of Lyocell, PBS, and acetate, which have a better hand feel, is lower, while the content of polyamide and polyester, which have a stronger synthetic feel, is higher. After dyeing, the iridescent fabric has a rich variety of colors, up to about five, with each fiber typically producing one color. Furthermore, the fabric's overall color fastness to rubbing, perspiration, and water all reach level 3 or higher.

[0058] Example 2

[0059] In this embodiment, jacquard fabric was used to conduct experiments on different plant dye compositions.

[0060] Jacquard fabric yarn composition:

[0061]

[0062] Dyeing process:

[0063] The amounts of plant-based indigo dye and other plant dyes used in the dyeing process are shown in Table 3.

[0064] Table 3: Prescriptions of plant dyes used in this embodiment

[0065]

[0066] The specific parameter settings for the two processes are as follows:

[0067] Staining 1: Plant-based indigo staining

[0068] Pre-reduction of plant indigo: First, add 100mL of alcohol and 500g of water to 600g of plant indigo and stir until there is no dry powder. Then add 5.5L of water. Next, dissolve 60g of NaOH and 150g of sodium hydrosulfite in 6L of water and add them to the mixture. Stir well and let stand for 30 minutes. The pH value is 11.1 and the reduction potential is -798mV.

[0069] Dyeing vat water intake (116L) – Fabric intake (115m, 11.6kg) – Heating operation for 4 stages (2℃ / min, 60℃) – Drainage – Water intake (86L) – Adding a solution of 8g NaOH, 18g sodium hydrosulfite, and 500mL water, then running for 4 stages – Adding pre-reduced plant indigo solution in 4 stages (filtered twice through a 200-mesh screen) – Dyeing at room temperature for 12 stages (adding NaOH and sodium hydrosulfite according to pH and reduction potential) – Drainage – Air oxidation for 6 stages – Water intake (H2O2 3mL / L) for 4 stages – Water washing for 4 stages – Acid washing (acetic acid added in small amounts multiple times according to pH) for 4 stages – Water washing for 4 stages (deoxygenase 1mL / L).

[0070] Dyeing 2: Overlaying with other plant dyes

[0071] Water intake (55L, 55L, 35L, and 72L for Examples 2-1, 2-2, 2-3, and 2-4, respectively) – Add plant dye solution in 4 stages (dye composition shown in Table 3, filtered twice through a 200-mesh screen) – Heat to 40℃ (1℃ / min) and run for 6 stages – Increase temperature to 50℃ (1℃ / min) and run for 8 stages – Increase temperature to 60℃ (1℃ / min) and run for 10 stages – Cool down to 40℃ and add mordant (5L of ferrous sulfate and hot water) in 2 stages – Heat to 40℃ (1℃ / min) and run for 4 stages – Increase temperature to 50℃ (1℃ / min) and run for 6 stages – Increase temperature to 60℃ (1℃ / min) and run for 10 stages – Drain – Wash with warm water for 6 stages (60℃) – Wash with cold water for 4 stages – Dehydrate – Dry (130℃ × 50s).

[0072] Fabric performance testing after dyeing:

[0073] The Lyocell iridescent fabrics dyed with plant dyes in each embodiment were tested. For color correlation testing, the fabric samples were placed in a standard light source color matching box with a D65 light source, the light illuminating the fabric samples perpendicularly at a 45° angle. Hue was categorized into nine colors: red, orange, yellow, green, blue, purple, blackish-gray, white, and brownish-red, with those in between grouped as the closest. Color difference was assessed based on a comprehensive consideration of hue, depth, and saturation, categorized into five levels with nine grades, the highest being level 5 and the lowest level 1. Color fastness to rubbing, water, and perspiration was tested and rated according to national standards GB / T 3920-2024, GB / T 5713-2013, and GB / T 3922-2013, respectively. The test results are shown in Table 4.

[0074] Table 4: Effects of different plant dye compositions on the color and properties of dyed jacquard iridescent fabrics

[0075]

[0076] As shown in Table 4, after dyeing with plant indigo in dyeing step 1, dyeing with different plant dyes in dyeing step 2 results in significantly different levels of color richness and color differences in the resulting iridescent fabric. However, all five colors can be achieved, and the overall color fastness to rubbing, perspiration, and water can reach level 3 or higher. In contrast, Examples 2-2, as control examples, although using the same dyeing steps as this invention (first dyeing with plant indigo, then with other plant dyes), use different plant dyes in dyeing step 2, and the dyeing pH is outside the range of this invention. Therefore, although the colors are more numerous than those of conventional plant dye-dyed fabrics, the number of hues and color differences are less than in this invention, failing to achieve the rich color and significant hue differences of the iridescent fabric of this invention.

[0077] Example 3

[0078] This example demonstrates an experiment on the pH value during staining.

[0079] The composition of the yarn in the jacquard fabric being processed is as follows:

[0080]

[0081]

[0082] The pH values ​​for the two steps in the dyeing process are shown in Table 5.

[0083] Table 5: pH values ​​for plant dye staining in this embodiment

[0084] Plant dyes for dyeing Example 3-1 Example 3-2 Example 3-3 Examples 3-4 Staining 1 pH = 9.2 pH = 9.5 pH = 8.5 pH = 10.8 Staining 2 pH = 2.6 pH = 4.4 pH = 2.1 pH = 4.9

[0085] The specific parameter settings for the two processes are as follows:

[0086] Staining 1: Plant-based indigo staining

[0087] Pre-reduction of plant indigo: First, add 80mL of alcohol and 500g of water to 560g of plant indigo and stir until there is no dry powder. Then add 5L of water. Next, dissolve 56g of NaOH and 140g of sodium hydrosulfite in 5.5L of water and add them to the mixture. Stir well and let stand for 30 minutes. The pH value is 11.1 and the reduction potential is -798mV.

[0088] Dyeing vat water intake (87L) – Fabric intake (65m, 8.7kg) – Heating operation for 4 stages (2℃ / min, 50℃) – Drainage – Water intake (60L) – Add NaOH 6g, sodium hydrosulfite 15g, and water 500mL solution and run for 4 stages – Add pre-reduced plant indigo solution in 4 stages (filtered twice through a 200-mesh screen) – Dyeing at room temperature for 10 stages (dyeing pH values ​​are shown in Table 5; NaOH and sodium hydrosulfite are added during the process according to pH value and reduction potential) – Drainage – Air oxidation for 6 stages – Water intake (H2O 23mL / L) and run for 4 stages – Water washing for 4 stages – Acid washing (acetic acid added in small amounts multiple times according to pH value) for 4 stages – Water washing for 4 stages (deoxygenase 1mL / L).

[0089] Staining 2: Overcoloring with rhubarb and red yeast rice extracts

[0090] Water intake (50L) – Add plant dyes (10L each of rhubarb and red yeast rice extract for staining, filtered twice through a 200-mesh screen, staining pH values ​​are shown in Table 5) in 4 stages – Heat to 40℃ (1℃ / min) and run 4 stages – Increase temperature to 50℃ (1℃ / min) and run 6 stages – Increase temperature to 60℃ (1℃ / min) and run 8 stages – Cool down to 40℃ and add mordant (130g ferrous sulfate, 4L hot water) in 2 stages – Heat to 40℃ (1℃ / min) and run 4 stages – Increase temperature to 50℃ (1℃ / min) and run 6 stages – Increase temperature to 60℃ (1℃ / min) and run 8 stages – Drain – Wash with warm water for 6 stages (60℃) – Wash with cold water for 4 stages – Dehydrate – Dry (125℃×60s).

[0091] Fabric performance testing after dyeing:

[0092] The Lyocell iridescent fabrics dyed with plant dyes in each embodiment were tested. For color correlation testing, the fabric samples were placed in a standard light source color matching box using a D65 light source, with the light shining perpendicularly onto the fabric sample and observed at a 45° angle. Hue was categorized into nine colors: red, orange, yellow, green, blue, purple, blackish-gray, white, and brownish-red, with those in between grouped as the closest. Color difference was assessed by considering hue, depth, and saturation, and was assigned to 5 levels with 9 grades, the highest being level 5 and the lowest level 1. The color fastness to rubbing, water, and perspiration was tested and rated according to national standards GB / T 3920-2024, GB / T 5713-2013, and GB / T 3922-2013, respectively. The test results are shown in Table 6.

[0093] Table 6: Effects of different pH values ​​on the color and properties of dyed jacquard iridescent fabrics

[0094]

[0095] As shown in Table 6, for dyeing with plant-based indigo (Staining 1), the colorfastness is slightly worse at lower pH values; at higher pH values, it can damage the silk threads, especially when the PBS strength has been reduced to the point of breakage. Therefore, a dyeing pH of 9–10 is preferred. For dyeing with other plant-based dyes (Staining 2), the dyeing properties of fibers vary at different pH values, requiring adjustment based on the desired color effect. A pH of 2.5–4.5 yields better results, more uniform dyeing, and higher utilization of the plant dyes.

[0096] The above Examples 1-3 and their test results demonstrate that the Lyocell iridescent fabric dyed with plant dyes of the present invention has rich and vivid colors, and the patterns are more three-dimensional and layered. When different yarns are used to make up the fabric, various styles of iridescent fabrics can also be obtained (see Example 1), which has a wide range of applications. The dyeing process is simple and can be obtained by dyeing with equipment. The dyeing effect is uniform color and excellent color fastness. It has the advantages of short preparation process, high production efficiency and good reproducibility, and is suitable for industrial application.

[0097] The above-described embodiments are merely illustrative of several feasible implementations of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention, nor are the embodiments intended to limit the scope of protection in the claims of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention. All equivalent implementations or changes that do not depart from the present invention should be included in the technology of the present invention.

Claims

1. A lyocell iridescent fabric based on plant dye dyeing, characterized in that, The iridescent fabric is obtained by dyeing with plant-based dyes and is woven from the following threads: Lyocell 30-40%, 20-30% mulberry silk Polyamide 15~20%, PBS 10-15%, Acetate 0~10%, Polyester 0~10%, The structure of the iridescent fabric consists of at least five or more blocks or lines of the same type of yarn.

2. The Lyocell iridescent fabric based on plant dyeing according to claim 1, characterized in that: The weave structure is plain weave, twill weave, double warp, double weft, or double layer.

3. A Lyocell iridescent fabric based on plant dyeing according to claim 1 or 2, characterized in that, The plant dyeing process includes two steps: dyeing with plant indigo dye and dyeing with other plant dyes. The other plant dyes are extracts of at least one of the following: rhubarb, scutellaria barbata, phellodendron amurense, scutellaria baicalensis, polygonum cuspidatum, arborvitae leaf, safflower, red yeast rice, fleeceflower root, cat's whiskers, purple-leaf plum, euphorbia humifusa, cornus officinalis, buckthorn, and grape skin.

4. The Lyocell iridescent fabric based on plant dye dyeing according to claim 3, characterized in that, The dyeing process of the plant indigo dye is as follows: water intake – fabric intake – heating to 50~70℃ and running for 3~5 cycles at a heating rate of 1~3℃ / min – draining – adding water at a liquor ratio of 1:5~1:20 – adding appropriate amounts of alkaline and reducing substances and running for 3~5 cycles – adding pre-reduced plant indigo – dyeing at room temperature for 5~20 cycles at a pH of 9~11.5 – draining – water oxidation for 4~6 cycles – water washing for 2~4 cycles – acid washing for 4~6 cycles – adding deoxygenating enzyme and water washing for 4~6 cycles – dehydration.

5. A Lyocell iridescent fabric based on plant dyeing according to claim 4, characterized in that, The pre-reduced plant indigo refers to: Step 1: Add an appropriate amount of alcohol and water to the indigo plant and stir until there is no dry powder. Step 2: Dissolve the alkaline and reducing substances separately in an appropriate amount of water, then add them to Step 1, stir well, let stand for 30-60 minutes, control the pH value to 10-11.5, and the reduction potential to be higher than -760mV.

6. A lyocell iridescent fabric based on plant dyeing according to claim 4, characterized in that: The alkaline substance is at least one of caustic soda, soda ash, and baking soda, and the reducing substance is at least one of sodium hydrosulfite and thiourea dioxide.

7. A lyocell iridescent fabric based on plant dyeing according to claim 4, characterized in that: The pH value for staining at room temperature is 9-10.

8. A lyocell iridescent fabric based on plant dyeing according to claim 4, characterized in that: The influent oxidation process involves the addition of 1-5 g / L H2O2.

9. A Lyocell iridescent fabric based on plant dyeing according to claim 3, characterized in that, The dyeing process for other plant dyes is as follows: water intake – fabric intake – heating to 50~80℃, running 2~5 cycles – adding plant dyes, heating to 40~60℃, dyeing for 10~20 cycles, controlling pH value to 2~5 – adding mordant, running 40~60℃ for 10~20 cycles – draining – washing with water at 40~60℃ – washing with cold water – dehydration.

10. A Lyocell iridescent fabric based on plant dye dyeing according to claim 9, characterized in that, The staining process involves first raising the temperature to 40℃ and running 2-4 cycles, then raising the temperature to 50℃ and running 4-6 cycles, and finally raising the temperature to 60℃ and running 6-10 cycles.

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