A madder dyed fabric and a method for producing the same

Abstract

The application discloses a hibiscus fabric and a preparation method thereof. The fabric is dyed by at least one of natural fiber fabric, chemical fiber fabric and blended or interwoven fabric of natural fiber and chemical fiber with hibiscus natural dye. The hibiscus natural dye is prepared by extracting and purifying hibiscus plant raw material with distilled water or pure water. The dyeing process of the fabric is carried out under the temperature condition below 60 DEG C. The dyeing wastewater can be recycled after treatment. The hibiscus fabric and the preparation method thereof adopt pure water to extract hibiscus pigment, and the dye does not contain heavy metal mordant and chemical synthetic components. The dyed fabric is skin-friendly and non-toxic, and meets the ecological textile standard. Through optimization of the extraction and dyeing process, the dyeing temperature is controlled below 60 DEG C, the damage of high temperature to anthocyanin pigment structure is effectively avoided, the natural color of the hibiscus dye is maintained, and the energy consumption is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of natural plant dyeing technology, specifically to a hollyhock-dyed fabric and its preparation method. Background Technology

[0002] With the improvement of people's living standards and the enhancement of environmental awareness, consumers have put forward higher requirements for the safety and eco-friendliness of textiles. Although traditional synthetic dyes have a complete color spectrum and good color fastness, their production process is often accompanied by serious environmental pollution, and some synthetic dyes contain carcinogenic aromatic amines or heavy metals, posing a potential threat to human health. Hollyhock, as a common ornamental plant, has petals rich in anthocyanin pigments, which are characterized by bright colors and natural non-toxicity. Existing hollyhock dyeing technology still has many shortcomings: 1. The extraction process is crude, resulting in low pigment purity, leading to dull colors and unstable hues in dyed fabrics; 2. The dyeing conditions are harsh, often requiring high temperature and high pressure or the addition of large amounts of chemical mordants to improve the dyeing rate and color fastness, which not only destroys the structure of natural pigments but also violates the original intention of eco-friendly textiles; 3. Water resources are wasted seriously, and dyeing wastewater is discharged directly without treatment, causing environmental pollution. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects and provide a hollyhock dyed fabric and its preparation method, which is low-temperature, environmentally friendly, requires no chemical mordants and can realize wastewater recycling, and can effectively solve the problems in the background technology.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A hollyhock-dyed fabric, wherein the fabric is made of at least one of natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers, and is dyed with hollyhock natural dye. The hollyhock natural dye is obtained by extracting and purifying hollyhock plant raw materials with distilled water or pure water. The dyeing process of the fabric is carried out at a temperature below 60°C, and the dyeing wastewater can be recycled after treatment.

[0005] The hollyhock natural dye is a pure plant extract, and its components include only water-soluble anthocyanin pigments and water, and it does not contain chemically synthesized dye components or heavy metal mordants.

[0006] Preferably, the natural fiber fabric includes plant fiber fabric and animal fiber fabric.

[0007] Preferably, the plant fiber fabric is selected from at least one of cotton fiber fabric, hemp fiber fabric, kapok fiber fabric or coconut shell fiber fabric, and the animal fiber fabric is selected from at least one of sheep wool fiber fabric, cashmere fiber fabric, mulberry silk fiber fabric, tussah silk fiber fabric or camel hair fiber fabric.

[0008] Preferably, the chemical fiber fabric includes man-made fiber fabric and synthetic fiber fabric.

[0009] Preferably, the man-made fiber fabric is selected from at least one of viscose fiber fabric, acetate fiber fabric, cupro fiber fabric, modal fiber fabric or lyocell fiber fabric, and the synthetic fiber fabric is selected from at least one of polyester fabric, nylon fabric, acrylic fabric, polypropylene fabric, spandex fabric or vinylon fabric.

[0010] Preferably, the hollyhock natural dye is a pure plant extract, whose components include only water-soluble anthocyanin pigments and water, and does not contain chemically synthesized dye components or heavy metal mordant residues.

[0011] A method for preparing hollyhock-dyed fabric, the method comprising the following steps: S1: Hollyhock natural dye extraction process, using hollyhock flowers as raw material, distilled water or pure water as extraction solvent, and obtaining hollyhock natural dye extract through immersion, filtration and purification. S2: Dye solution preparation process, the hollyhock natural dye extract obtained in step S1 is mixed with water to prepare the dye solution; S3: Fabric pretreatment process, which pretreats at least one of the following fabrics: natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers. S4: Low-temperature dyeing process, in which the fabric after the pretreatment in step S3 is immersed in the dyeing solution prepared in step S2 and dyed at a temperature below 60°C. S5: Post-dyeing treatment process, which involves washing, fixing and drying the fabric after dyeing in step S4. S6: Dyeing wastewater recycling process, collecting the dyeing wastewater generated in steps S4 and S5, and reusing it in step S2 dyeing solution preparation and / or step S5 water washing process after purification treatment.

[0012] Preferably, the hollyhock natural dye extraction process in step S1 specifically includes: drying and pulverizing hollyhock flowers, mixing them with distilled water or pure water as solvent at a material-to-liquid ratio of 1:10 to 1:50, adjusting the pH value to 2 to 5, extracting at 40°C to 65°C for 30 to 120 minutes, filtering to remove flower residue, and obtaining a crude extract of hollyhock flower pigment; the purification step uses macroporous adsorption resin column chromatography or membrane separation to purify the crude extract, collecting the eluent, concentrating under reduced pressure to obtain the hollyhock natural dye extract.

[0013] Preferably, the dyeing temperature of the low-temperature dyeing process in step S4 is 20°C to 50°C, the dyeing time is 30 to 120 minutes, and the liquor ratio is 1:10 to 1:40; and no chemical mordant or synthetic fixing agent is added in this process.

[0014] Preferably, the dyeing wastewater recycling process in step S6 specifically includes: after the dyeing wastewater is treated by filtration, adsorption or membrane separation to remove impurities, it is directly reused in the dyeing solution preparation in step S2 and / or the water washing process in step S5, and the recycling rate of the dyeing wastewater is not less than 70%; the preparation method adopts industrial-scale production equipment.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This application uses pure water to extract hollyhock pigment. The dye does not contain heavy metal mordants or chemically synthesized components, and the dyed fabric is skin-friendly and non-toxic, meeting the standards for eco-textiles. By optimizing the extraction and dyeing process, the dyeing temperature is controlled below 60℃, effectively avoiding the damage of high temperatures to the anthocyanin pigment structure, maintaining the natural color of the hollyhock dye, and significantly reducing energy consumption. A complete wastewater recycling mechanism has been established. After treatment, the dyeing wastewater is reused for solution preparation and washing, with a recycling rate of over 70%, significantly reducing wastewater discharge and water consumption, and lowering production costs. The method of this application is applicable to various fabrics such as cotton, linen, silk, wool, and recycled fibers, and has broad industrial application prospects. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the preparation method of the hollyhock-dyed fabric of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 The present invention provides a technical solution: A hollyhock-dyed fabric, wherein the fabric is made of at least one of natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers, and is dyed with hollyhock natural dye. The hollyhock natural dye is obtained by extracting and purifying hollyhock plant raw materials with distilled water or pure water. The dyeing process of the fabric is carried out at a temperature below 60°C, and the dyeing wastewater can be recycled after treatment.

[0019] Natural fiber fabrics include plant fiber fabrics and animal fiber fabrics.

[0020] Plant fiber fabrics are selected from at least one of cotton fiber fabrics, hemp fiber fabrics, kapok fiber fabrics, or coconut shell fiber fabrics, while animal fiber fabrics are selected from at least one of sheep wool fiber fabrics, cashmere fiber fabrics, mulberry silk fiber fabrics, tussah silk fiber fabrics, or camel hair fiber fabrics.

[0021] Chemical fiber fabrics include man-made fiber fabrics and synthetic fiber fabrics.

[0022] The man-made fiber fabric is selected from at least one of viscose fiber fabric, acetate fiber fabric, cupro fiber fabric, modal fiber fabric or lyocell fiber fabric, and the synthetic fiber fabric is selected from at least one of polyester fabric, nylon fabric, acrylic fabric, polypropylene fabric, spandex fabric or vinylon fabric.

[0023] Hollyhock natural dye is a pure plant extract. Its components include only water-soluble anthocyanin pigments and water, and it does not contain chemically synthesized dyes or heavy metal mordants.

[0024] A method for preparing hollyhock-dyed fabric, the method comprising the following steps: S1: Hollyhock natural dye extraction process, using hollyhock flowers as raw material, distilled water or pure water as extraction solvent, and obtaining hollyhock natural dye extract through immersion, filtration and purification. S2: Dye solution preparation process, the hollyhock natural dye extract obtained in step S1 is mixed with water to prepare the dye solution; S3: Fabric pretreatment process, which pretreats at least one of the following fabrics: natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers. S4: Low-temperature dyeing process, in which the fabric after the pretreatment in step S3 is immersed in the dyeing solution prepared in step S2 and dyed at a temperature below 60°C. S5: Post-dyeing treatment process, which involves washing, fixing and drying the fabric after dyeing in step S4. S6: Dyeing wastewater recycling process, collecting the dyeing wastewater generated in steps S4 and S5, and reusing it in step S2 dyeing solution preparation and / or step S5 water washing process after purification treatment.

[0025] The extraction process of hollyhock natural dye in step S1 specifically includes: drying and pulverizing hollyhock flowers, mixing them with distilled water or pure water at a ratio of 1:10 to 1:50, adjusting the pH to 2 to 5, extracting at 40℃ to 65℃ for 30 to 120 minutes, filtering to remove flower residue, and obtaining a crude extract of hollyhock flower pigment; the purification step uses macroporous adsorption resin column chromatography or membrane separation to purify the crude extract, collecting the eluent, concentrating under reduced pressure to obtain the hollyhock natural dye extract.

[0026] In step S4, the low-temperature dyeing process involves a dyeing temperature of 20°C to 50°C, a dyeing time of 30 to 120 minutes, and a liquor ratio of 1:10 to 1:40; and no chemical mordants or synthetic fixing agents are added in this process.

[0027] The dyeing wastewater recycling process in step S6 specifically includes: after removing impurities by filtration, adsorption or membrane separation, the dyeing wastewater is directly reused in the dyeing solution preparation in step S2 and / or the water washing process in step S5, and the recycling rate of the dyeing wastewater is not less than 70%; the preparation method adopts industrial-scale production equipment.

[0028] Example 1: Preparation of hollyhock-dyed cotton fabric This embodiment provides a method for preparing hollyhock-dyed cotton fabric, including the following steps: 1. Extraction of natural hollyhock dye: Take dried, deep red hollyhock petals, crush them and pass them through a 40-mesh sieve. Add distilled water at a material-to-liquid ratio of 1:20 (g / mL), adjust the pH value to 3.0 with citric acid, and extract in a 50℃ water bath for 60 minutes with constant stirring. Filter to remove flower residue to obtain crude hollyhock pigment extract. Purify the crude extract by chromatography using an AB-8 macroporous adsorption resin column. First, wash away impurities with distilled water, then elute with 50% ethanol. Collect the red eluent, concentrate under reduced pressure to remove ethanol, and obtain a high-purity hollyhock natural dye extract. 2. Preparation of staining solution: Mix the above extract with distilled water at a volume ratio of 1:10 to prepare the staining solution; 3. Fabric pretreatment: Take pure cotton plain weave fabric, desizing, scouring, and bleaching it, then wash it with water until neutral, and dry it for later use. 4. Low-temperature dyeing: Immerse the pretreated cotton fabric in the dyeing solution with a liquor ratio of 1:20, and dye at a constant temperature of 45℃ for 60 minutes. No chemical mordants are added during the dyeing process. 5. Post-treatment and wastewater reuse: After dyeing, the fabric is taken out, the floating dye is rinsed with a small amount of cold water, and then dried after being treated with natural tannic acid solution for color fixation. The dyeing residue and initial wash wastewater are collected, and after being treated with activated carbon adsorption and ultrafiltration membrane filtration to remove impurities, the pigment concentration is tested. After adding an appropriate amount of fresh dye extract, it is reused in the preparation of the next batch of dyeing solution.

[0029] Tests showed that the cotton fabric produced in this embodiment has a soft and natural color, presenting an elegant purplish-red hue. The color fastness (washing resistance and abrasion resistance) both reach level 3-4 or above, and no heavy metal residues were detected in the fabric.

[0030] Example 2: Preparation of Hollyhock-dyed Silk Fabric The difference between this embodiment and Embodiment 1 is that: the dyeing object is mulberry silk fabric; in the extraction process, the extraction temperature is adjusted to 40℃, the extraction time is 90 minutes, and the pH value is adjusted to 2.5; in the low-temperature dyeing process, the dyeing temperature is controlled at 30℃, and the dyeing time is 90 minutes; in the wastewater recycling process, the wastewater is treated and reused in the washing process.

[0031] The silk fabric prepared in this embodiment has a smooth hand feel, a unique natural luster, and high color vibrancy, demonstrating the good affinity of marshmallow pigment for protein fibers.

[0032] Example 3: Industrial-scale preparation and verification of wastewater recycling efficiency This embodiment uses industrial-scale production equipment for verification.

[0033] The natural dye of hollyhock is extracted according to the method of claim 8, and the viscose fiber fabric is dyed according to the low-temperature dyeing process of claim 9 (dyeing temperature 50°C, time 45 minutes).

[0034] Wastewater recycling: Dyeing and washing wastewater (approximately 1000L) is collected and treated by a filtration, adsorption, and membrane separation system. The treated water is clear with a significantly reduced COD value. The treated water is directly reused for the preparation of the dyeing solution and washing in the next batch. After five consecutive batches of recycling tests, the recycling rate of dyeing wastewater reached 78%, and the color difference (ΔE) of the subsequent batches of fabrics was less than 1.0, indicating that wastewater recycling did not have a negative impact on dyeing quality.

[0035] Comparative Example 1 (existing technology) used a traditional high-temperature boiling method to extract marshmallow pigment (100℃, 60 minutes), and then dyed cotton fabric at 90℃, adding alum as a mordant. The dyeing wastewater was directly discharged. The results showed that the fabric obtained in Comparative Example 1 was dark yellow with uneven color and significant damage to fabric strength (caused by high temperature). In contrast, the fabrics obtained in Examples 1-3 of this invention had pure color, good hand feel, and achieved zero emissions and low-cost operation.

[0036] Example Performance Testing and Data Analysis To verify the actual technical effects of the hollyhock-dyed fabric and its preparation method described in this invention, the applicant selected typical samples (black hollyhock plant-dyed fabric and hollyhock plant-dyed silk fabric) prepared using the method of this embodiment and commissioned a third-party authoritative testing institution with CMA, CNAS, and ilac-MRA qualifications to conduct relevant performance tests. The test results are shown in the table below: Table 1: Combustion performance test results

[0037] Table 2: UV protection performance test results Summary of Data Analysis and Technological Advantages Based on the test data from the aforementioned authoritative third-party testing organization with internationally recognized ilac-MRA accreditation, the following conclusions can be drawn, fully demonstrating the beneficial effects of the present invention: Excellent flame retardant safety: Table 1 shows that the black hollyhock plant-dyed fabric prepared by this invention exhibits excellent performance in flammability tests. The damaged lengths in the warp and weft directions are 84 mm and 90 mm, respectively, far below the standard limit (≤150 mm); the afterflame time and smoldering time are both 0.0 seconds, and no molten droplets that would cause the degreased cotton to burn are produced. This indicates that the fabric has excellent flame-retardant properties, effectively delaying the spread of fire and significantly improving the safety of textile use, making it particularly suitable for scenarios with high fire protection requirements.

[0038] Excellent UV protection: Table 2 shows that the measured UV protection factor (UPF) of the hollyhock plant-dyed silk fabric is greater than 50, far exceeding the national standard (>40); the long-wave ultraviolet transmittance T(UVA)AV is only 0.15%, far below the standard limit (<5%). This proves that while hollyhock natural dyes give the fabric a unique color, they also endow the fabric with excellent UV resistance, effectively blocking UVA and UVB radiation, providing good sun protection and skin care, and demonstrating the multifunctional advantages of natural plant dyeing.

[0039] The authority and reliability of the data: The above test results were all issued by authoritative institutions with CMA (Certification and Accreditation for Testing and Inspection Organizations), CNAS (China National Accreditation Service for Conformity Assessment), and ilac-MRA (International Laboratory Accreditation Cooperation Multilateral Recognition Agreement). This means that the technical effects of this invention not only meet Chinese national standards, but its testing capabilities and data quality have also reached internationally recognized levels, fully demonstrating that the technical solution of this invention is mature and reliable, and has extremely high practical value and prospects for promotion.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hollyhock-dyed fabric, characterized in that, The fabric is made of at least one of natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers, dyed with hollyhock natural dye. The hollyhock natural dye is obtained by extracting and purifying hollyhock plant raw materials with distilled water or pure water. The dyeing process of the fabric is carried out at a temperature below 60°C, and the dyeing wastewater can be recycled after treatment.

2. The hollyhock-dyed fabric according to claim 1, characterized in that, The natural fiber fabrics include plant fiber fabrics and animal fiber fabrics.

3. The hollyhock-dyed fabric according to claim 2, characterized in that, The plant fiber fabric is selected from at least one of cotton fiber fabric, hemp fiber fabric, kapok fiber fabric or coconut shell fiber fabric, and the animal fiber fabric is selected from at least one of sheep wool fiber fabric, cashmere fiber fabric, mulberry silk fiber fabric, tussah silk fiber fabric or camel hair fiber fabric.

4. The hollyhock-dyed fabric according to claim 1, characterized in that, The chemical fiber fabrics include man-made fiber fabrics and synthetic fiber fabrics.

5. The hollyhock-dyed fabric according to claim 4, characterized in that, The man-made fiber fabric is selected from at least one of viscose fiber fabric, acetate fiber fabric, cupro fiber fabric, modal fiber fabric or lyocell fiber fabric, and the synthetic fiber fabric is selected from at least one of polyester fabric, nylon fabric, acrylic fabric, polypropylene fabric, spandex fabric or vinylon fabric.

6. The hollyhock-dyed fabric according to claim 1, characterized in that, The hollyhock natural dye is a pure plant extract, and its components include only water-soluble anthocyanin pigments and water, and it does not contain chemically synthesized dye components or heavy metal mordants.

7. A method for preparing a hollyhock-dyed fabric, characterized in that, The method for preparing the hollyhock-dyed fabric according to any one of claims 1-6 comprises the following steps: S1: Hollyhock natural dye extraction process, using hollyhock flowers as raw material, distilled water or pure water as extraction solvent, and obtaining hollyhock natural dye extract through immersion, filtration and purification. S2: Dye solution preparation process, the hollyhock natural dye extract obtained in step S1 is mixed with water to prepare the dye solution; S3: Fabric pretreatment process, which pretreats at least one of the following fabrics: natural fiber fabric, chemical fiber fabric, and blended or interwoven fabric of natural and chemical fibers. S4: Low-temperature dyeing process, in which the fabric after the pretreatment in step S3 is immersed in the dyeing solution prepared in step S2 and dyed at a temperature below 60°C. S5: Post-dyeing treatment process, which involves washing, fixing and drying the fabric after dyeing in step S4. S6: Dyeing wastewater recycling process, collecting the dyeing wastewater generated in steps S4 and S5, and reusing it in step S2 dyeing solution preparation and / or step S5 water washing process after purification treatment.

8. The method for preparing hollyhock-dyed fabric according to claim 7, characterized in that, The hollyhock natural dye extraction process in step S1 specifically includes: drying and pulverizing hollyhock flowers, mixing them with distilled water or pure water at a material-to-liquid ratio of 1:10 to 1:50, adjusting the pH to 2 to 5, extracting at 40°C to 65°C for 30 to 120 minutes, filtering to remove flower residue, and obtaining a crude extract of hollyhock flower pigment; the purification step uses macroporous adsorption resin column chromatography or membrane separation to purify the crude extract, collecting the eluent, concentrating under reduced pressure to obtain the hollyhock natural dye extract.

9. The method for preparing hollyhock-dyed fabric according to claim 7, characterized in that, The low-temperature dyeing process described in step S4 has a dyeing temperature of 20°C to 50°C, a dyeing time of 30 to 120 minutes, and a liquor ratio of 1:10 to 1:40; and no chemical mordants or synthetic fixing agents are added in this process.

10. The method for preparing hollyhock-dyed fabric according to claim 7, characterized in that, The dyeing wastewater recycling process in step S6 specifically includes: after removing impurities by filtration, adsorption or membrane separation, the dyeing wastewater is directly reused in the dyeing solution preparation in step S2 and / or the water washing process in step S5, and the recycling rate of the dyeing wastewater is not less than 70%; the preparation method adopts industrial-scale production equipment.

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