A fabric based on saffron dyeing and a preparation method thereof

Abstract

This invention discloses a saffron-dyed fabric and its preparation method, relating to the field of saffron-dyed fabrics. The fabric includes a natural fiber substrate and a saffron pigment layer attached to the natural fiber substrate. The natural fiber substrate is selected from at least one of silk, wool, cotton, and linen. An alum mordant layer is fixed inside the natural fiber substrate, and the fabric surface is loaded with natural volatile aromatic substances from saffron. The fabric hue is any one of light yellow, bright yellow, orange-yellow, or orange-red. This invention enhances pigment binding by fixing an alum mordant layer inside the natural fiber substrate and employs a cool, ventilated, and naturally air-dried process to avoid high-temperature damage. Simultaneously, it combines multi-stage extraction and hue control technology to effectively solve the problems of low color fastness, easy loss of aroma, and limited hue. The fabric has the advantages of high color fastness, complete preservation of natural volatile aromatic substances, diverse hue selection from light yellow to orange-red, and uniform color.

Description

Technical Field

[0001] This invention relates to the field of saffron-dyed fabrics, specifically to a fabric based on saffron dyeing and its preparation method. Background Technology

[0002] Saffron, also known as crocus or saffron crocus, is a rare and high-end natural plant dye, fragrance, and medicinal raw material. Only the stigma filaments possess coloring properties, making the raw material expensive and suitable only for high-end textile custom dyeing. The core coloring substances in saffron are crocin and crocetin, which are water-soluble carotenoid glycosides and the only natural yellow plant pigments that simultaneously possess both coloring and fragrance functions.

[0003] The existing saffron plant dyeing process has the following core defects:

[0004] Poor color fastness and uneven dyeing: Conventional processes involve dyeing first and then mordating, resulting in weak bonding between pigments and fibers, making the fabric prone to fading after washing and sun exposure; the lack of standardized mordating pretreatment process leads to obvious color differences between the front and back of the fabric.

[0005] Low raw material utilization and high cost: Saffron raw material is expensive, and traditional single boiling extraction leaves a large amount of pigment residue. A large amount of effective pigment is discarded by the filter residue, which greatly increases the dyeing production cost.

[0006] Limited color control: Existing processes can only produce a single yellow color, and the hue cannot be adjusted with simple additives, making it difficult to cover the demand for multiple color systems such as light yellow, bright yellow, orange-yellow, and orange-red;

[0007] The finished product has no natural fragrance and is prone to aging and fading: High-temperature drying and sun exposure after dyeing will destroy the volatile fragrance substances of saffron and accelerate the photodecomposition of saffron pigments, causing the fabric to turn gray quickly after storage.

[0008] Poor fabric compatibility: The fabric material is not distinguished and chemical fibers and natural fibers are dyed in the same way. Chemical fibers can hardly be dyed, resulting in waste of raw materials.

[0009] There is no standardized ratio for the process parameters: there is no differentiated amount of saffron for thin scarves, thick shawls, and long garments, and small-area products are prone to over-feeding, resulting in cost waste.

[0010] Existing publicly available saffron dyeing techniques mostly only describe the simple process of boiling saffron in water for dyeing, failing to address the series of technical challenges mentioned above, such as fastness, color, raw material utilization, and aroma retention. These techniques cannot meet the market demands for high-end natural and eco-friendly fabrics, handmade scarves, and formal wear fabrics. There is an urgent need for a new type of saffron-dyed fabric and its standardized preparation method. Summary of the Invention

[0011] The purpose of this invention patent is to provide a fabric based on saffron dyeing and its preparation method.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a fabric based on saffron dyeing, comprising a natural fiber base and a saffron pigment layer attached to the natural fiber base; the natural fiber base is selected from at least one of silk, wool, cotton, and linen; an alum mordant layer is fixed inside the natural fiber base, and the fabric surface is loaded with natural volatile aromatic substances of saffron; the fabric hue is any one of light yellow, golden yellow, orange-yellow, or orange-red; the fabric is formed by naturally air-drying in a cool and ventilated place.

[0013] Furthermore, this paper also proposes a method for preparing fabrics based on saffron dyeing, including the following steps:

[0014] S1. Material preparation: The dyeing material is dried saffron filaments, the mordant is alum, and the base fabric is natural fiber fabric.

[0015] Feeding standard: 5-15g of dried saffron filaments and 5g of alum per 1kg of fabric;

[0016] S2. Fabric pretreatment: 1. Desizing and washing: Boil the fabric in a neutral soap or desizing agent solution for 20 minutes, and rinse thoroughly with clean water; 2. Pre-mordant treatment: Prepare an alum solution, control the water temperature at 40-50℃, immerse the wet fabric in the mordant solution for 30 minutes, and do not rinse after mordant treatment.

[0017] S3. Multi-stage extraction of saffron dye: Soak dried saffron filaments in cold water for 2 hours, boil over low heat and simmer for 30 minutes to obtain the first dye solution; add water to the residue for a second extraction, and combine the two filtrates.

[0018] S4. Constant temperature dyeing and hue control: 1. Combine dyeing solutions and heat to 60-70℃, add the pre-mordated wet fabric, continuously turn the fabric, and keep the temperature constant for 30-60 minutes; 2. After dyeing, turn off the heat, soak the fabric in the dyeing solution to cool and stand for 2-4 hours or seal overnight.

[0019] S5. Finishing after color fixing and air drying: Rinse the fabric with cold water until the rinse water is clear; place the fabric in a cool and ventilated place to air dry naturally for 24-48 hours; after air drying, wash lightly with cold water and neutral detergent, and air dry again to obtain the finished saffron-dyed fabric.

[0020] Preferably, in step S3, the amount of water added for the secondary extraction is 30% to 50% of the amount of water used for the primary extraction.

[0021] Preferably, in step S3, the dye solution is kept naturally alkaline, and the finished product is orange-red. Adding edible white vinegar to the dye solution to adjust the acidity results in a bright yellow finished product.

[0022] Preferably, in step S4, the constant temperature dyeing time is 40-60 minutes for orange-red fabrics and 30-40 minutes for light yellow and bright yellow fabrics.

[0023] Preferably, in step S5, the air-drying environment is shaded from direct sunlight, and the ambient temperature is controlled between 15 and 28°C.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This application provides a fabric and preparation method based on saffron dyeing. By fixing an alum mordant layer inside the natural fiber base to enhance the pigment binding force, and using a cool, ventilated, and natural air-drying process to avoid high-temperature damage, and combining multi-stage extraction and hue control technology, the problem of low color fastness, easy loss of aroma and single hue is effectively solved. It has the advantages of high color fastness, complete preservation of natural volatile aromatic substances, and a diverse selection of light yellow to orange-red hues with uniform color. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] In the saffron dyeing process, there are defects in color fastness due to weak binding force between pigment and fiber. Specifically, pigment is lost in large quantities under washing and sun exposure conditions. At the same time, the lack of standardized mordant pretreatment process results in a significant reduction in the uniformity of coloring on both sides of the fabric. The utilization rate of raw materials is limited by the single boiling extraction process, and effective pigments are discarded in the filter residue, resulting in the ineffective consumption of expensive raw materials. The lack of a color control mechanism results in the hue being fixed at a single yellow, making it impossible to achieve a continuous color range from light yellow to orange-red through auxiliaries. The high-temperature drying and sun exposure process accelerates the photodecomposition of saffron pigment and destroys volatile aroma substances, causing the finished product to lose its aroma and age and turn gray quickly. In addition, the process does not differentiate between fiber material characteristics, and uses the same treatment method for chemical fibers and natural fibers, resulting in almost no effective coloring of chemical fiber bases. The process parameters lack standards for the amount of material to be added for different product specifications, and lightweight fabrics are prone to cost waste due to excessive material addition. All of the above problems restrict the feasibility of producing high-end eco-friendly fabrics.

[0028] If the aforementioned technical problems persist, the dyed finished products will fail to meet the basic requirements of high-end textiles for color fastness and visual consistency. Raw material waste will further increase production costs. The limitation of a single hue will hinder the development of multi-color products. The lack of fragrance and rapid fading characteristics will weaken the market competitiveness of the products. Defects in the compatibility of chemical fibers will cause local dyeing failures in the fabric, ultimately causing the process to completely lose its application value in the field of handmade scarves and formal wear fabrics.

[0029] In this regard, this application provides a fabric based on saffron dyeing, comprising the natural fiber base and a saffron pigment layer attached to the natural fiber base;

[0030] The natural fiber base is selected from at least one of silk, wool, cotton, and linen;

[0031] The natural fiber base has an alum mordant layer fixed inside, and the fabric surface is loaded with natural volatile aromatic substances from saffron;

[0032] The fabric is any one of the following colors: light yellow, bright yellow, orange-yellow, or orange-red.

[0033] The fabric is dried naturally in a cool, ventilated place to take shape.

[0034] For ease of understanding, the following explains some key terms in this embodiment:

[0035] Natural fiber substrates refer to fibrous materials derived from nature, whose main components are protein or cellulose. These fibrous materials have good moisture absorption, breathability, and skin-friendliness, making them suitable as dyeing carriers. In this embodiment, the natural fiber substrate may include various types such as silk, wool, cotton, linen, or combinations thereof.

[0036] The saffron pigment layer refers to the colored area formed by the natural pigment extracted from saffron adhering to and penetrating into the interior of the natural fiber matrix. This pigment layer gives the fabric a specific color, and its formation process interacts with the molecular structure of the fiber material to achieve coloring.

[0037] Alum mordant layer refers to a layer formed during the dyeing process by using alum as a mordant to form a stable complex with the natural fiber substrate and saffron pigment, thereby fixing it inside the fiber. The main function of this mordant layer is to enhance the binding force between the pigment and the fiber and improve the color fastness.

[0038] Saffron's natural volatile aromatic substances refer to the volatile organic compounds with unique aromas contained in saffron. Under specific processing conditions, these substances can be retained and loaded onto the fabric surface, giving the fabric its natural aromatic properties.

[0039] Hue refers to the type or name of a color, such as light yellow, bright yellow, orange-yellow, or orange-red. In this embodiment, the hue of the fabric can be achieved by adjusting the dyeing process parameters to meet different color requirements.

[0040] Air drying in a cool, well-ventilated place refers to drying fabrics in a dark, temperature-appropriate, and well-ventilated environment, allowing moisture to evaporate naturally. This drying method helps protect the stability of saffron pigments and retains the volatile aromatic substances on the fabric surface.

[0041] This embodiment provides a fabric based on saffron dyeing. The fabric comprises a natural fiber base and a saffron pigment layer attached to the natural fiber base. The natural fiber base can be composed of various natural fiber materials; for example, silk can be used as the base, as its protein structure can form a good bond with the saffron pigment; or cellulose fibers such as cotton or linen can be used, as their hydrophilicity facilitates pigment adsorption. In the preparation process, the natural fiber base is first prepared, and then it is brought into contact with saffron pigment through methods such as dyeing, thereby allowing the pigment to adhere to the fiber surface and penetrate into the interior, forming a saffron pigment layer.

[0042] The natural fiber base is selected from at least one of silk, wool, cotton, and linen. For example, when producing high-end silk fabrics, silk can be chosen as the natural fiber base, as its luster and feel match the precious properties of saffron. When producing products with good warmth retention, wool can be chosen as the base. For everyday textiles, cotton or linen fibers offer economical and comfortable options. In practical applications, depending on the intended use and required characteristics of the final product, a single type of natural fiber can be selected, or different types of natural fibers can be blended to obtain a base fabric with composite properties.

[0043] The natural fiber substrate has an alum mordant layer fixed inside. Before dyeing, the natural fiber substrate can undergo pre-mordant treatment, for example, by soaking the fabric in an alum aqueous solution, allowing the alum molecules to penetrate into the fiber. As a common mordant, alum's metal ions can form stable complex structures with fiber molecules and saffron pigment molecules, thus firmly fixing the pigment inside the fiber. This internal fixation helps improve color fastness and reduces pigment loss during washing or rubbing.

[0044] The fabric surface is coated with natural volatile aromatic substances from saffron. During the dyeing and drying processes, by controlling the temperature and drying method, the aromatic volatile components of saffron can be retained and adsorbed or attached to the fabric surface. For example, avoiding high-temperature drying can effectively reduce the volatilization of these aromatic substances. This coating of aromatic substances gives the fabric a unique natural fragrance, enhancing the product's added value.

[0045] The fabric's hue can be any of light yellow, bright yellow, orange-yellow, or orange-red. The final hue of the fabric can be achieved by adjusting various parameters during the dyeing process. For example, different shades of yellow can be obtained by controlling factors such as the concentration of saffron pigment, dyeing time, and temperature. In some cases, the saffron pigment can also exhibit a hue change from yellow to orange-red by adjusting the pH value of the dye bath without introducing other dyes.

[0046] The fabric is naturally air-dried in a cool, well-ventilated place. After dyeing, the fabric is not dried at high temperatures, but rather left to air-dry in a cool, well-ventilated, and dark environment. This drying method avoids the damage that high temperatures can cause to the structure of saffron pigments and volatile aromatic substances, thus preserving the fabric's original color and natural fragrance. At the same time, natural air-drying also helps stabilize the fabric's fiber structure, preventing shrinkage or deformation caused by rapid drying.

[0047] In other embodiments, this application proposes a method for preparing a fabric based on saffron dyeing. The method includes the following steps:

[0048] S1. Material preparation: The dyeing material is dried saffron filaments, the mordant is alum, and the base fabric is this natural fiber fabric.

[0049] Feeding standard: 5-15g of dried saffron filaments and 5g of alum per 1kg of fabric;

[0050] S2. Fabric pretreatment: 1. Desizing and washing: Boil the fabric in a neutral soap or desizing agent solution for 20 minutes, and rinse thoroughly with clean water; 2. Pre-mordant treatment: Prepare an alum solution, control the water temperature at 40-50℃, immerse the wet fabric in the mordant solution for 30 minutes, and do not rinse after mordant treatment.

[0051] S3. Multi-stage extraction of saffron dye: Soak dried saffron filaments in cold water for 2 hours, boil over low heat and simmer for 30 minutes to obtain the first dye solution; add water to the residue for a second extraction, and combine the two filtrates.

[0052] S4. Constant temperature dyeing and hue control: 1. Combine dyeing solutions and heat to 60-70℃, add the pre-mordated wet fabric, continuously turn the fabric, and keep the temperature constant for 30-60 minutes; 2. After dyeing, turn off the heat, soak the fabric in the dyeing solution to cool and stand for 2-4 hours or seal overnight.

[0053] S5. Finishing after color fixing and air drying: Rinse the fabric with cold water until the rinse water is clear; place the fabric in a cool and ventilated place to air dry naturally for 24-48 hours; after air drying, wash lightly with cold water and neutral detergent, and air dry again to obtain the finished saffron-dyed fabric.

[0054] This application effectively solves the core problems of poor color fastness, low raw material utilization, and limited color control in existing technologies by combining multi-stage extraction of saffron dye with alum pre-mordant treatment using specific process parameters. Specifically, the multi-stage extraction process ensures the full extraction of pigment from dried saffron filaments, avoiding the waste of pigment residue caused by traditional single boiling extraction, and significantly improving raw material utilization. The alum pre-mordant treatment forms a stable complex structure inside the fiber, enhancing the binding force between the pigment and the fiber, thereby improving color fastness under washing and sun exposure conditions and solving the problem of color difference between the front and back of the fabric. The constant temperature dyeing and hue control steps achieve continuous hue changes from light yellow, bright yellow, orange-yellow to orange-red by precisely controlling the temperature and time range, overcoming the limitation of existing processes that can only obtain a single yellow color. The shade drying process is carried out in a light-proof and low-temperature environment, avoiding the damage of natural volatile aromatic substances of saffron to high-temperature drying and sun exposure, preserving the natural fragrance of the fabric, and preventing the graying phenomenon of the fabric caused by the photodecomposition of saffron pigment. Furthermore, standardized material feeding ratios and process parameter settings tailored to different fabric types improve process adaptability and avoid ineffective dyeing of synthetic fiber fabrics and excessive material feeding in small-area products. Through the above technical solutions, this application achieves high-quality, high-efficiency, and multi-color standardized production of saffron-dyed fabrics, meeting the market demand for high-end natural and ecological fabrics.

[0055] Furthermore, this application proposes that in step S3, the amount of water added for the secondary extraction is 30% to 50% of the amount used in the initial extraction. This is to precisely control the amount of solvent used in the secondary extraction process, ensuring sufficient dye extraction while avoiding excessive dilution of the dye solution due to excessive water, which would affect the subsequent dyeing effect. This ratio is set to optimize the dye extraction efficiency and the concentration of the dye solution.

[0056] Furthermore, this application proposes a scheme in step S3 where the dye solution remains naturally alkaline, resulting in an orange-red finished product; and where edible white vinegar is added to the dye solution to adjust the acidity, resulting in a bright yellow finished product. Maintaining the natural alkalinity of the dye solution refers to the pH state of the dye solution obtained after the multi-stage extraction of saffron filaments in step S3, without any additional pH adjustment. This natural alkalinity is an inherent characteristic of saffron pigment during dissolution and extraction in aqueous solution, and is the basis for obtaining a specific hue. Orange-red is the typical color exhibited by saffron pigment when combined with natural fibers in an alkaline or weakly alkaline environment. Edible white vinegar, as a common and mild acidifier, can safely and effectively change the pH of the dye solution, thereby affecting the color state of the pigment. One implementation method is to add edible white vinegar in batches and small amounts to the combined dye solution before or during the constant-temperature dyeing in step S4, while continuously stirring, and monitoring the pH value of the dye solution in real time using pH test paper or a pH meter until the desired acidity range is reached, for example, a pH value of around 6.0. A bright yellow finish refers to the hue of the dyed fabric obtained after dyeing under acidic conditions. Bright yellow is a typical color exhibited by saffron pigments when combined with natural fibers in an acidic environment, forming a striking contrast with the orange-red color under alkaline conditions.

[0057] The present application's solution achieves flexible control over the final hue of the dyed fabric by precisely adjusting the acidity and alkalinity of the saffron dye solution. In step S3 of the above preparation method, after multi-stage extraction of dried saffron filaments, the resulting dye solution is naturally weakly alkaline. Under this natural alkaline environment, the main coloring substances in saffron (such as crocin) exist in a specific chemical structure or aggregated state. When the pre-mordanted wet fabric is immersed in this dye solution for constant-temperature dyeing, the pigment molecules can be effectively adsorbed and fixed onto the natural fiber substrate, thereby giving the finished fabric a warm orange-red hue.

[0058] To obtain different hues, this application further proposes that adding edible white vinegar to the dye bath can effectively adjust its pH to acidic. In an acidic environment, the chemical structure of saffron pigment or its aggregation state in solution undergoes a reversible change, resulting in a bright yellow color. When fabric is dyed in this acidic dye bath, a bright and vibrant bright yellow finished fabric can be obtained. This method of simply adjusting the pH of the dye bath allows the same saffron dye bath to produce two distinctly different hues, greatly enriching the color choices for saffron-dyed fabrics, solving the problem of fixed hues in single dyeing methods, and providing a technical basis for personalized fabric customization.

[0059] Furthermore, this application further proposes a method for preparing the above-mentioned fabric based on saffron dyeing, wherein the constant temperature dyeing time of 40-60 min in step S4 is used for orange-red fabric, and 30-40 min is used for light yellow and bright yellow fabric.

[0060] The phrase "constant temperature dyeing time of 40-60 minutes for orange-red fabric" refers to extending the constant temperature dyeing process in step S4 for 40 to 60 minutes when preparing fabric with a target hue of orange-red. The constant temperature dyeing time is one of the key parameters affecting the amount of dye adsorbed and the depth of color. A longer dyeing time helps the saffron pigment layer to penetrate and adhere more fully to the natural fiber base, thereby obtaining a deeper and more saturated orange-red color.

[0061] This application achieves precise control over the dyeing process by correlating the dyeing time in the isothermal dyeing step S4 with the hue of the target fabric. Specifically, when preparing an orange-red fabric, a longer isothermal dyeing time, such as 40 to 60 minutes, is used. This allows the saffron pigment layer sufficient time to fully combine with the natural fiber substrate, resulting in a deeper and more saturated orange-red hue. Conversely, when the target hue is a light yellow or bright yellow fabric, a relatively shorter isothermal dyeing time, such as 30 to 40 minutes, is used. This helps limit the amount of dye adsorbed, preventing the color from becoming too dark, and thus accurately presenting the desired light yellow or bright yellow tone. This strategy of adjusting the dyeing time according to the target hue allows the degree of dye fixation on the natural fiber substrate to match the expected color depth, thereby improving the stability and controllability of the dyeing effect.

[0062] By employing the aforementioned technical solutions, the constant-temperature dyeing time can be precisely set for fabrics with different target hues, effectively solving the problem of difficulty in accurately controlling the final hue with a single dyeing time. This results in more stable and controllable fabric hues, enabling the flexible production of saffron-dyed fabrics in different shades such as light yellow, bright yellow, and orange-red, according to market demand or design requirements, significantly improving product diversity and the precision of the dyeing process.

[0063] Furthermore, this application proposes that in the finishing step after color fixing and air drying, the air drying environment be set to be shaded from direct sunlight, and the ambient temperature controlled between 15 and 28°C. Shading from light means avoiding exposure to visible light or ultraviolet radiation during the air drying process. Saffron pigment, as a natural plant dye, is sensitive to light, especially in humid conditions. Light exposure can accelerate its oxidation and decomposition, leading to color fading or unevenness. Shading from light can be achieved by air drying in a windowless or well-shaded indoor environment, or by using an opaque covering to shield the fabric from direct sunlight during air drying. Avoiding direct sunlight means ensuring that the fabric is not directly exposed to sunlight during the air drying process. Controlling the ambient temperature between 15 and 28°C means maintaining the surrounding air temperature within a specific suitable range during the air drying period. Excessively high temperatures may cause moisture evaporation to be too rapid, resulting in uneven dye migration and color spots, while also accelerating the volatilization of saffron's natural volatile aromatic substances; excessively low temperatures will prolong the air drying time, increasing the risk of the fabric becoming damp and developing microbial growth. Maintaining the temperature within the range of 15–28°C helps ensure that the fabric dries evenly and slowly, which is beneficial for the stable fixation of pigments and the effective retention of aromatic substances. This temperature range can be achieved by using temperature control equipment, adjusting the indoor ventilation system, or combining it with ambient humidity control.

[0064] This application's solution effectively inhibits the photo-oxidative degradation of saffron pigments by avoiding direct sunlight, especially direct sunlight, during the fabric's air-drying process, thus ensuring the stability and durability of the fabric's color. Simultaneously, precisely controlling the ambient temperature within the suitable range of 15–28℃ avoids both uneven pigment migration and excessively rapid volatilization of aromatic substances caused by high temperatures, and excessively long drying times and potential microbial contamination caused by low temperatures. This comprehensive environmental control measure allows the saffron pigments to be more stably fixed on the natural fiber substrate and maximizes the retention of saffron's natural volatile aromatic substances, thereby ensuring the finished fabric has a uniform and bright color and maintains its unique aroma. Based on the principle of natural air-drying in a cool, ventilated place, this solution significantly improves the quality and stability of saffron-dyed fabrics through meticulous management of light and temperature conditions.

[0065] The following example will provide a more detailed explanation of the above technical solution:

[0066] Manufacturer A is a high-end textile customization company that wants to produce a batch of saffron-dyed silk fabrics with a unique natural fragrance and good colorfastness.

[0067] Manufacturer A adopted the fabric dyeing technology based on saffron provided in this embodiment. First, Manufacturer A chose silk fabric because silk has excellent moisture absorption and luster, which can well showcase the color of saffron. Before dyeing, the silk fabric was pretreated by boiling it in a neutral soap or desizing agent solution for 20 minutes and rinsing it thoroughly with clean water. An alum solution was prepared, with the water temperature controlled at 40-50℃. The wet silk fabric was then immersed in the mordant solution for 30 minutes, allowing the alum molecules to fully penetrate and fix into the interior of the silk fibers, forming an alum mordant layer. After mordant dyeing, no rinsing was required; the fabric was dyed directly.

[0068] Meanwhile, the saffron dye solution is prepared. First, dried saffron filaments are soaked in cold water for 2 hours, then simmered over low heat for 30 minutes, and filtered to obtain the initial dye solution. Assuming 1000 mL of water was used for the initial extraction, 300 mL to 500 mL of water can be added for the second extraction of the residue. For example, 400 mL of water can be added for the second extraction, followed by simmering over low heat again and filtering. The resulting second dye solution is combined with the first dye solution to form the final saffron dye solution. This method ensures complete extraction of the dye while maintaining an appropriate concentration of the dye solution.

[0069] Subsequently, Manufacturer A immersed the pre-mordanted silk fabric in saffron dye solution for dyeing. The preparation of the dye solution and the dyeing process were carefully controlled to ensure that the saffron pigment could evenly adhere to and penetrate into the silk fibers, forming a uniform saffron pigment layer. During the dyeing process, Manufacturer A adjusted the dyeing temperature and hue according to market demand. If an orange-red fabric was desired, the combined dye solution was heated to 65°C, the pre-mordanted wet fabric was immersed in, the fabric was continuously turned over, and the dyeing process was maintained at a constant temperature for 50 minutes. During this process, the dye solution maintained its natural alkalinity without any pH adjustment. To obtain a bright yellow fabric, after heating the combined dye liquor to 60-70°C, before adding the pre-mordanted wet fabric, slowly add an appropriate amount of edible white vinegar to the dye liquor. For example, depending on the volume of the dye liquor and the target pH value, add the edible white vinegar in batches while stirring thoroughly until the pH value of the dye liquor shows acidity when tested with pH test paper. Then, immerse the pre-mordanted wet fabric in the acidified dye liquor, continuously turn the fabric, and set the constant temperature dyeing time to 35 minutes.

[0070] After dyeing, the silk fabric is not dried at high temperatures. Instead, it is placed in a specially designed drying chamber. The walls and ceiling of this chamber are constructed of opaque materials, and there are no windows to ensure a completely dark and sun-free environment for natural air drying. This method avoids the damage that high temperatures cause to the natural volatile aromatic compounds of saffron, allowing the silk fabric to retain and absorb the unique natural fragrance of saffron. Simultaneously, natural air drying protects the stability of the saffron pigments, preventing them from aging and fading rapidly due to light or high temperatures.

[0071] Finally, the silk fabric is rinsed with cold water until the rinse water is clear, and then placed in a cool and ventilated place to air dry naturally for 24 to 48 hours. After air drying, it is gently washed with cold water and neutral detergent, and then air dried again to obtain the finished saffron-dyed silk fabric.

[0072] Through the above process, Manufacturer A successfully produced a batch of silk fabrics with beautiful colors, a natural saffron fragrance, and excellent colorfastness. This silk fabric not only has even and long-lasting color but also emits a pleasant natural aroma, greatly enhancing the product's market competitiveness.

[0073] Based on the above examples, the technical solution of this embodiment demonstrates a significant technical contribution in solving the problems of the prior art.

[0074] Compared to the poor colorfastness and uneven dyeing problems commonly found in existing saffron dyeing processes, this embodiment significantly enhances the binding force between saffron pigment and fiber by fixing an alum mordant layer inside the natural fiber substrate. In the example above, after alum pre-mordination, the saffron pigment adheres more firmly to the inside of the fiber in the silk fabric, effectively avoiding the problems of weak pigment-fiber binding force in traditional processes, such as easy fading after washing and sun exposure, and obvious color difference between the front and back of the fabric. This internal fixing mordant method gives the dyed fabric superior washability and lightfastness.

[0075] To address the shortcomings of existing processes where finished products lack natural aroma and are prone to aging and fading, this embodiment effectively solves this problem by loading the fabric surface with the natural volatile aromatic substances of saffron and using a cool, ventilated, and natural air-drying method. In this example, the silk fabric avoids high-temperature drying and direct sunlight exposure after dyeing, allowing the precious volatile aromatic substances in saffron to be retained and adsorbed onto the surface of the silk fabric, giving the product a unique natural fragrance. At the same time, this gentle drying method also protects the structural stability of the saffron pigment, delaying the photodecomposition and oxidation processes of the pigment, thus making the fabric's color more durable and less prone to graying.

[0076] Furthermore, this embodiment overcomes the limitation of existing processes that only allow for single-color control by enabling the fabric hue to be any one of light yellow, bright yellow, orange-yellow, or orange-red. In the example, manufacturer A can obtain bright yellow silk fabric according to its needs, indicating that this technical solution can achieve the conversion of saffron pigment between different hues by adjusting process parameters, meeting the market demand for multi-color products, and not just being limited to a single yellow.

[0077] This embodiment further enhances fabric adaptability by specifying that the natural fiber base is selected from at least one of silk, wool, cotton, and linen. This contrasts with existing technologies that fail to differentiate fiber materials and directly dye both synthetic and natural fibers, leading to raw material waste. By selecting natural fibers with good affinity for saffron pigments, this embodiment ensures the stability of the dyeing effect and the effective utilization of raw materials.

[0078] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A fabric based on saffron dyeing, characterized in that, It includes a natural fibrous base and a saffron pigment layer attached to the natural fibrous base; The natural fiber base is selected from at least one of silk, wool, cotton, and linen; The natural fiber base has an alum mordant layer fixed inside, and the fabric surface is loaded with natural volatile aromatic substances from saffron. The fabric hue is any one of light yellow, bright yellow, orange-yellow or orange-red; The fabric is dried naturally in a cool, ventilated place to form its shape.

2. A method for preparing a fabric based on saffron dyeing as described in claim 1, characterized in that, Includes the following steps: S1. Material preparation: The dyeing material is dried saffron filaments, the mordant is alum, and the base fabric is natural fiber fabric. Feeding standard: 5-15g of dried saffron filaments and 5g of alum per 1kg of fabric; S2. Fabric pretreatment:

1. Desizing and washing: Boil the fabric in a neutral soap or desizing agent solution for 20 minutes, and rinse thoroughly with clean water; 2. Pre-mordant treatment: Prepare an alum solution, control the water temperature at 40-50℃, immerse the wet fabric in the mordant solution for 30 minutes, and do not rinse after mordant treatment. S3. Multi-stage extraction of saffron dye: Soak dried saffron filaments in cold water for 2 hours, boil over low heat and simmer for 30 minutes to obtain the first dye solution; add water to the residue for a second extraction, and combine the two filtrates. S4. Constant temperature dyeing and hue control:

1. Combine dyeing solutions and heat to 60-70℃, add the pre-mordated wet fabric, continuously turn the fabric, and keep the temperature constant for 30-60 minutes; 2. After dyeing, turn off the heat, soak the fabric in the dyeing solution to cool and stand for 2-4 hours or seal overnight. S5. Finishing after color fixing and air drying: Rinse the fabric with cold water until the rinse water is clear; place the fabric in a cool and ventilated place to air dry naturally for 24-48 hours; after air drying, wash lightly with cold water and neutral detergent, and air dry again to obtain the finished saffron-dyed fabric.

3. The method for preparing a fabric based on saffron dyeing according to claim 2, characterized in that, In step S3, the amount of water added for the second extraction is 30% to 50% of the amount of water used in the first extraction.

4. The method for preparing a fabric based on saffron dyeing according to claim 1, characterized in that, In step S3, the dye solution is kept naturally alkaline, and the finished product is orange-red. Adding edible white vinegar to the dye solution adjusts the acidity, and the finished product becomes bright yellow.

5. The method for preparing a fabric based on saffron dyeing according to claim 1, characterized in that, In step S4, the constant temperature dyeing time is 40-60 minutes for orange-red fabrics and 30-40 minutes for light yellow and bright yellow fabrics.

6. The method for preparing a fabric based on saffron dyeing according to claim 1, characterized in that, In step S5, the air-drying environment should be shaded from direct sunlight, and the ambient temperature should be controlled between 15 and 28°C.