CN109021611B

CN109021611B - Extraction method and application of natural plant dye

Info

Publication number: CN109021611B
Application number: CN201811032235.3A
Authority: CN
Inventors: 陶建平
Original assignee: Zhejiang Jishan Printing&dyeing Co ltd
Current assignee: Zhejiang Jishan Printing&dyeing Co ltd
Priority date: 2018-09-05
Filing date: 2018-09-05
Publication date: 2021-02-19
Anticipated expiration: 2038-09-05
Also published as: CN109021611A

Abstract

The invention belongs to the field of textile dyeing and finishing, and particularly relates to a method for extracting cyrtomium fortunei natural plant dye and application thereof in a printing and dyeing process, wherein the method comprises the steps of 1) removing impurities from cyrtomium fortunei raw materials, cleaning, drying in the air, crushing into 80-150 meshes, then adding the obtained product into an extracting agent for soaking, and after cyrtomium fortunei is fully wetted, continuously adding a pH value regulator to regulate the pH value of a solution to be about 9-14; then adding extraction auxiliary agent, heating the solution to about 60-100 ℃, preserving the temperature for about 60-180min, and filtering; repeatedly extracting for about 3-5 times, mixing the leaching solutions obtained many times to obtain natural dye stock solution; 2) decompressing and concentrating the natural dye stock solution obtained in the step 1), and then freeze-drying to obtain powdery natural dye. The extraction process is simple, and the extraction efficiency can be unexpectedly improved by selecting the extraction auxiliary agent with a specific composition.

Description

Extraction method and application of natural plant dye

Technical Field

The invention belongs to the field of textile dyeing and finishing, and particularly relates to an extraction method of a cyrtomium fortunei natural plant dye and application of the cyrtomium fortunei natural plant dye in a printing and dyeing process.

Background

Along with the improvement of living standard of people, more and more people begin to advocate natural and healthy living style, people pay more and more attention to the aspects of self health, health care and the like, and the harm of part of synthetic dyes to human health and ecological environment is more and more remarkable. The existing research results show that twenty-three carcinogenic aromatic amines, more than one hundred synthetic dyes are possible to generate carcinogenic substances, and more than twenty synthetic dyes are allergic to the skin, so that the European Union successively issues regulations including forbidden dyes and other chemicals in recent years, such as the European Union 67/648/EC instruction, the European Union 2001/C96E/18 instruction, the European Union 2002/61/EC instruction, the European Union 2003/3/EC instruction, the ECO-Label new standard, the chemical REACH regulation and the like, which severely restricts the textile export in China. Moreover, the synthetic dyes also cause a great deal of pollution to the environment during the production process.

Compared with traditional synthetic dyes, natural dyes are concerned with due to their unique non-toxicity, harmlessness and no pollution, and many natural dyes using Chinese herbal medicines as raw materials also have health care functions for human bodies. The development of natural resources is more urgent due to the need for environmental protection. With the improvement of ecological environmental awareness of people, the development and application of natural dyes are inevitably and continuously developed under the development trend of increasingly paying attention to environmental protection and ecological dyeing and finishing processing.

The natural pigment has wide sources, so that the natural pigment is increasingly the key point for developing and obtaining novel dyes. The research of natural dyes mainly comprises the aspects of extraction process, dyeing performance, dyeing mechanism and the like. International research on natural dyes has mainly focused on asia, in particular, korea, japan, and the like. Research on natural dyes has become part of the technical partnership project, united nations' development program (UNDP), in developing countries. Although the history of natural plant dyeing applied in China is long, the research on the system development and utilization of natural dyes is very little except that some minority nationalities still adopt plant dyes to produce handicrafts after the natural dyes are replaced by synthetic dyes. Until the beginning of the 21 st century, with the international rise of natural dyes, the domestic research reports on natural dye dyeing are increasing.

The cyrtomium rhizome, also called as the canal and node of the cyrtomium, is a perennial herb of fern, and has short rhizome, leaf cluster, pinnate multiple leaves and small leaf sickle shape. It is cold, slightly bitter and slightly toxic. The main components of the medicine are complex phloroglucinol derivatives and the like, have antiviral effect and strong inhibitory effect on influenza virus, and have the effects of clearing away heat and toxic materials, expelling parasites, cooling blood, stopping bleeding and the like. It can be used for treating wind-heat type common cold, damp-heat type macula, hematemesis, hematochezia, and metrorrhagia.

The rhizoma Osmundae has high pigment content, and can be used as a natural brown dye for dyeing and printing textiles, and has antibacterial, antiviral, and mosquito larva killing effects. Therefore, the brown natural dye is extracted from the cyrtomium fortunei and applied to textile dyeing, and has very important significance for expanding the color spectrum and the application range of the natural dye, developing functional textiles and improving the grade and the additional value of the textiles.

For example, the method for extracting the cyrtomium fortunei natural dye disclosed in the Chinese patent CN01177542A comprises the steps of cleaning and airing the plant cyrtomium fortunei, mechanically crushing, then adding the plant cyrtomium fortunei into 5-20 times of water solution for soaking, adding sodium hydroxide, sodium carbonate, sodium silicate or sodium phosphate after the cyrtomium fortunei is fully wetted, adjusting the pH value of the solution to 10-13, heating to 95-100 ℃, preserving the temperature for 60-90 min, and filtering; leaching the filter residue with an alkali solution with the pH value of 10-13, filtering, and combining the two leaching solutions to obtain a natural dye stock solution; and then, concentrating, solidifying and crushing the extracted crude solution of the cyrtomium fortunei natural dye to obtain the powdery natural dye. Although the method provides a process for extracting the cyrtomium fortunei, the process has low extraction rate of natural pigments contained in the cyrtomium fortunei on the whole.

For example, the university of Zhejiang university of Master academic thesis "extraction of natural dye and its application in cotton fabric" discloses a conventional extraction process for Cyrtomium fortunei natural dye, wherein the optimal extraction conditions are as follows: 10g/L of accelerant ZS-L, the temperature is 100 ℃, the time is 180min, and the material ratio is 1: 30, the extraction times are 2 times. However, the reference is made throughout this document to no mention of what is specifically the accelerator ZS-l used.

Disclosure of Invention

Therefore, the technical problem to be solved by the present application is how to improve the extraction rate of the conventional cyrtomium fortunei natural dye extraction process on cyrtomium fortunei natural dye (i.e. effective components used as pigments), and how to utilize the cyrtomium fortunei natural dye to dye real silk fabrics.

In order to solve the above technical problems, the inventors of the present application have earnestly studied and found that an extraction process having a synergistic effect can significantly improve the extraction rate of a cyrtomium fortunei natural dye by optimizing and adjusting the process conditions during extraction, particularly by introducing an extraction aid having a specific composition, thereby solving the above technical problems. The technical scheme of the invention is as follows: the invention discloses a method for extracting a rhizoma dryopteris crassirhizomae natural dye, which comprises the following steps:

1) removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 80-150 mesh powder, soaking in extractant, adding pH regulator after rhizoma Osmundae is sufficiently wetted, and regulating pH to 9-14; then adding extraction auxiliary agent, heating the solution to about 60-100 ℃, preserving the temperature for about 60-180min, and filtering; repeatedly extracting for about 3-5 times, mixing the leaching solutions obtained many times to obtain natural dye stock solution;

2) decompressing and concentrating the natural dye stock solution obtained in the step 1), and then freeze-drying to obtain powdery natural dye.

The extractant is a mixed solvent of ethanol and water, and the volume content of the ethanol is about 50 to about 80 v.%, based on the total volume of the mixed solvent.

The pH regulator is preferably an alkali metal hydroxide, carbonate, silicate and/or phosphate, more preferably sodium hydroxide, sodium carbonate, sodium silicate and/or sodium phosphate.

The extraction auxiliary agent is clay selected from kaolin, bentonite and attapulgite; preferably a mixture of bentonite and attapulgite, wherein the amount of bentonite is from about 30 to about 50 wt.%, more preferably from about 35 to about 45 wt.%, more preferably about 40 wt.%. The bentonite is preferably sodium bentonite and organic bentonite, and more preferably organic bentonite.

The organic bentonite can be selected from commercial products, and can also be prepared by the following method:

firstly, water is taken as a dispersion medium, impurities in bentonite are removed to prepare a suspension with the bentonite content of about 15-18 wt.%, and then high-speed shearing dispersion is carried out to ensure that the particle size reaches the clay level; reacting the slurry with a quaternary ammonium salt having from 15 to 24 carbon atoms containing at least one group, the quaternary ammonium salt being about 20 to 40 wt.% of the amount of bentonite clay, heating the slurry appropriately, and controlling the pH of the reaction to be alkaline; then filtered, washed and dried at room temperature to 50 ℃.

The addition amount of the extraction aid is preferably 5-30g/L, and the volume of the solution is taken as a reference; more preferably 10 to 25 g/L; more preferably 15 g/L.

The material ratio in the step 1), i.e. the weight ratio of the cyrtomium fortunei raw material added into the extracting agent/(the weight of the solution obtained after the extracting agent and the cyrtomium fortunei raw material are mixed), is preferably 1: 10-1: 50, more preferably 1: 20-1: 40, most preferably 1: 25.

the particle size of the pulverized cyrtomium fortunei raw material in the step 1) is preferably about 100-130 meshes, and more preferably 120 meshes; the pH of the solution is preferably about 10-13, more preferably 11; the temperature at leaching is preferably about 70-90 deg.C, more preferably about 80 deg.C; the leaching time is preferably about 80-160min, more preferably about 120 min; the number of extraction times is preferably 4.

The application also discloses the application of the Cyrtomium fortunei natural dye obtained by the extraction method in the dyeing process of real silk fabrics, wool products and cotton fabrics.

1. The method comprises the steps of preparing dye liquor from natural dye of cyrtomium fortunei by adopting a conventional direct dyeing method without using a mordant, dyeing real silk fabrics or wool products, washing, drying, soaping, washing and drying to obtain brown real silk fabrics or wool products.

2. The method comprises preparing dye solution from rhizoma Osmundae natural dye, dyeing silk fabric or wool product, washing with water, drying, soaping, washing with water, drying, adding mixed rare earth chloride such as lanthanum chloride and cerium chloride, mordanting, washing with water, drying, soaping, washing with water, and drying.

3. The method comprises preparing dye solution from rhizoma Osmundae natural dye, dyeing silk fabric or wool product, washing with water, drying, soaping, washing with water, drying, adding metal aluminum salt such as aluminum sulfate, mordanting, washing with water, drying, soaping, washing with water, and drying to obtain reddish brown silk fabric or wool product.

4. The method comprises the steps of preparing dye liquor from cyrtomium fortunei natural dye by adopting a conventional dyeing-first mordant method, dyeing real silk fabric or wool products, washing, drying, soaping, washing and drying, then adding metal ferrous salt such as ferrous sulfate, carrying out mordant dyeing, washing, drying, soaping, washing and drying, and obtaining brown real silk fabric or wool products.

5. Adopting a conventional direct dyeing method, firstly sequentially modifying cotton fabrics by using commercially available cationic modifiers and polyethylene glycol; preparing a dye solution from a cyrtomium fortunei natural dye, and dyeing cotton fabrics; then washing and drying, and then soaping, washing and drying to obtain the brown cotton fabric.

The application has the beneficial effects that:

1. compared with the existing natural dye extraction, the extraction process is simple, and the extraction efficiency can be obviously improved by introducing a specific extraction auxiliary agent; and the preparation process is very environment-friendly and does not cause environmental pollution.

2. The Cyrtomium fortunei natural dye extracted by the application has the advantages of no toxicity, no harm, no pollution, biodegradability and strong environmental compatibility, and has excellent color fastness when being used for dyeing real silk fabrics, wool products and cotton fabrics.

3. The dyed fabric or product prepared from the Cyrtomium fortunei natural dye extracted by the method is safe to use, and does not have carcinogenic and teratogenic effects or cause anaphylactic reaction when being directly contacted with human skin; but also has certain health-care function of medicines, can play the roles of resisting bacteria and diminishing inflammation and can prevent mosquito bites.

4. The dyed fabric or product prepared by the Cyrtomium fortunei natural dye extracted by the method has uniform color, soft color and typical nature, and can meet the aesthetic requirements of modern people; and different colors, such as brown, reddish brown, yellowish brown, etc., can be obtained by selecting different mordants.

Additional advantages will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The following advantages are realized and attained, particularly in light of the chemical compositions, methods, and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.

Supplemental definition

The materials, compounds, compositions, and components described herein can be used in, or can be used in combination with, the methods and compositions described herein, or can be used in the practice of the methods and in the preparation of the compositions, or as products obtained by the methods. It is to be understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each and every combination and permutation of these compounds may not be explicitly made, each is specifically contemplated and described herein. For example, if an extraction aid component is disclosed and discussed, and a number of alternative solid state forms of that component are discussed, each and every combination and permutation of the possible reference aid components and solid state forms is specifically contemplated unless specifically indicated to the contrary. This concept applies to all aspects of this application, including but not limited to steps in methods of making and using the disclosed compositions. Thus, if there are a plurality of additional steps that can be performed it is understood that each of these additional steps can be performed by any specific embodiment or combination of embodiments of the disclosed methods, and that each such combination is specifically contemplated and should be considered disclosed.

In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:

it must be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include both one and more than one (i.e., two, including two) unless the context clearly dictates otherwise. Thus, for example, reference to "a pH adjuster as described" can include a single pH adjuster, or a mixture of two or more pH adjusters, and the like.

Unless otherwise indicated, numerical ranges in this application are approximate and thus may include values outside of the ranges. Ranges of values can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the numerical ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

Reference in the specification and concluding claims to parts by weight of a particular element or component in a composition or article refers to the weight relationship between that element or component and any other elements or components in the composition or article, expressed as parts by weight. Thus, in a composition comprising 2 parts by weight of component X and 5 parts by weight of component Y, X and Y are present in a weight ratio of 2:5 and are present in this ratio regardless of whether additional components are included in the composition.

Unless specifically indicated to the contrary, or implied by the context or customary practice in the art, all parts and percentages referred to herein are by weight and the weight percentages of a component are based on the total weight of the composition or product in which it is included.

Reference throughout this application to "comprising," "including," "having," and similar language is not intended to exclude the presence of any optional components, steps or procedures, whether or not any optional components, steps or procedures are specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all methods claimed through use of the term "comprising" may include one or more additional steps, apparatus parts or components and/or materials. In contrast, the term "consisting of … …" excludes any component, step, or procedure not specifically recited or recited. Unless otherwise specified, the term "or" refers to the listed members individually as well as in any combination.

Furthermore, the contents of any referenced patent or non-patent document in this application are incorporated by reference in their entirety, especially with respect to definitions disclosed in the art (where not inconsistent with any definitions specifically provided herein) and general knowledge.

Detailed Description

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and/or methods described and claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless otherwise indicated, parts are parts by weight, temperatures are in degrees Celsius or at ambient temperature, and pressures are at or near atmospheric. There are many variations and combinations of reaction conditions (e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges) and conditions that can be used to optimize the purity and yield of the product obtained by the process. Only reasonable routine experimentation will be required to optimize such process conditions.

Example 1:

removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 80 mesh, adding into mixed solvent of ethanol and water, and soaking at material ratio of 1: 10, and the volume content of ethanol in the mixed solvent is 50 v.%, based on the total volume of the mixed solvent. After the cyrtomium rhizome is fully wetted, continuously adding sodium carbonate, and adjusting the pH value of the solution to 9; then adding an extraction aid, namely a mixture of organic bentonite and attapulgite, wherein the addition amount of the extraction aid is 5g/L, and the content of the organic bentonite in the mixture is 30 wt.%; heating the solution to about 60 ℃, preserving the temperature for about 180min, and filtering; repeatedly extracting for about 3 times, and mixing the leaching solutions obtained for many times to obtain natural dye stock solution;

then, the obtained natural dye stock solution is firstly decompressed and concentrated, and then is frozen and dried to obtain powdery cyrtomium fortunei natural dye.

The organic bentonite is prepared by the following method:

firstly, water is taken as a dispersion medium, impurities in bentonite are removed, suspension with the bentonite content of about 16 wt.% is prepared, and then high-speed shearing dispersion is carried out, so that the particle size reaches the clay level; reacting the slurry with a quaternary ammonium salt having at least one group with 20 carbon atoms, the quaternary ammonium salt being about 30 wt.% of the amount of bentonite clay, heating to 60 ℃, and controlling the pH at 8 during the reaction; then filtered, washed and dried at 45 ℃.

The natural dye of the basket fern is prepared into dye liquor by adopting a conventional direct dyeing method without a mordant, the real silk fabric or the wool product is dyed, and then the real silk fabric or the wool product is washed and dried, and finally the brown real silk fabric or the brown wool product is obtained by soaping, washing and drying.

Example 2

Removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 150 mesh powder, adding into mixed solvent of ethanol and water, and soaking at a material ratio of 1: 50, and the volume content of ethanol in the mixed solvent is 80 v.%, based on the total volume of the mixed solvent. After the cyrtomium rhizome is fully wetted, continuously adding sodium hydroxide, and adjusting the pH value of the solution to be 14; then adding a mixture of an extraction aid, namely organic bentonite and attapulgite, wherein the addition amount of the extraction aid is 30g/L, the content of the organic bentonite in the mixture is 50 wt.%, heating the solution to about 100 ℃, preserving the temperature for about 60min, and filtering; repeatedly extracting for about 5 times, and mixing the leaching solutions obtained many times to obtain natural dye stock solution;

The organobentonite used was prepared according to the extraction method of example 1.

Example 3

Removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 100 mesh powder, adding into mixed solvent of ethanol and water, and soaking at material ratio of 1: 20, and the volume content of ethanol in the mixed solvent is 60 v.%, based on the total volume of the mixed solvent. After the cyrtomium rhizome is fully wetted, continuously adding sodium hydroxide, and adjusting the pH value of the solution to 10; then adding a mixture of an extraction aid, namely organic bentonite and attapulgite, wherein the addition amount of the extraction aid is 10g/L, the content of the organic bentonite in the mixture is 35 wt.%, heating the solution to about 70 ℃, preserving the temperature for about 160min, and filtering; repeatedly extracting for about 4 times, and mixing the leaching solutions obtained for multiple times to obtain natural dye stock solution;

Example 4

Removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 130 meshes, adding into a mixed solvent of ethanol and water, and soaking at a material ratio of 1: 40, and the volume content of ethanol in the mixed solvent is 70 v.%, based on the total volume of the mixed solvent. After the cyrtomium rhizome is fully wetted, continuously adding sodium phosphate, and adjusting the pH value of the solution to 13; then adding a mixture of an extraction aid, namely organic bentonite and attapulgite, wherein the addition amount of the extraction aid is 25g/L, the content of the organic bentonite in the mixture is 45 wt.%, heating the solution to about 90 ℃, keeping the temperature for about 80min, and filtering; repeatedly extracting for about 4 times, and mixing the leaching solutions obtained for multiple times to obtain natural dye stock solution;

Example 5

Removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 120 mesh, adding into mixed solvent of ethanol and water, and soaking at material ratio of 1: 25, and the volume content of ethanol in the mixed solvent is 65 v.%, based on the total volume of the mixed solvent. After the cyrtomium rhizome is fully wetted, continuously adding sodium phosphate, and adjusting the pH value of the solution to 11; then adding a mixture of an extraction aid, namely organic bentonite and attapulgite, wherein the addition amount of the extraction aid is 15g/L, the content of the organic bentonite in the mixture is 40 wt.%, heating the solution to about 80 ℃, preserving the temperature for about 120min, and filtering; repeatedly extracting for about 4 times, and mixing the leaching solutions obtained for multiple times to obtain natural dye stock solution;

Example 6

The preparation process is basically the same as that of example 5, except that: the bentonite is sodium bentonite.

Example 7

The preparation process is basically the same as that of example 5, except that: the bentonite used is commercially available organobentonite.

Example 8

The preparation process is basically the same as that of example 5, except that: the extraction aid used is only a single organobentonite.

Example 9

The preparation process is basically the same as that of example 5, except that: the extraction aid used is only a single attapulgite.

Example 10

The preparation process is basically the same as that of example 5, except that: the extraction aid used was only a single kaolin clay.

Example 11

The preparation process is basically the same as that of example 5, except that: the extraction auxiliary agent is a mixture of kaolin, bentonite and attapulgite, and the weight ratio of the kaolin to the bentonite to the attapulgite is 1: 1: 1.

example 12

The preparation process is basically the same as that of example 5, except that: the content of bentonite in the mixture of organic bentonite and attapulgite is 25 wt.%.

Example 13

The preparation process is basically the same as that of example 5, except that: the content of bentonite in the mixture of organic bentonite and attapulgite is 55 wt.%.

Comparative example 1

The preparation process is basically the same as that of example 5, except that: the rhizoma Osmundae has pulverized rhizoma Osmundae material with particle size of 70 mesh, pH of solution of 8, ethanol content of 40 v.% in mixed solvent as extractant, and extraction is repeated for 2 times.

Comparative example 2

The preparation process is basically the same as that of example 5, except that: the rhizoma Osmundae material has particle size of 160 mesh after pulverizing, pH of solution of 15, ethanol content of 90 v.% in mixed solvent used as extractant, and extraction is repeated for 5 times.

Comparative example 3

The preparation process is basically the same as that of example 5, except that: the addition amount of the extraction aid is 4g/L, and the material ratio is 1: 5.

comparative example 4

The preparation process is basically the same as that of example 5, except that: the addition amount of the extraction aid is 35g/L, and the material ratio is 1: 55.

comparative example 5

The preparation process is basically the same as that of example 5, except that: the addition amount of the extraction aid is 4g/L, and the material ratio is 1: 25.

comparative example 6

The preparation process is basically the same as that of example 5, except that: the extractant is only water, and is not a mixed solvent of ethanol and water.

Comparative example 7

The preparation process is basically the same as that of example 5, except that: the extractant is only ethanol, and is not a mixed solvent of ethanol and water.

Comparative example 8

The preparation process is basically the same as that of example 5, except that: no extraction aid was added.

Comparative example 9

The procedure of example 1 of CN01177542A was followed, wherein the filter residue was leached with 10 times the amount of aqueous solution.

Extraction Rate testing and test results

The extraction rates of the natural dyes of Cyrtomium fortunei of the preparation processes of examples 1 to 7 and comparative examples 1 to 8 were respectively tested, and the test results are shown in Table 1.

The extraction rate (%) of the rhizoma Osmundae natural dye is the weight of the finally obtained powdery rhizoma Osmundae natural dye/the weight of the pulverized rhizoma Osmundae raw material.

TABLE 1 extraction Rate data

As can be seen from the test results of table 1, the present application unexpectedly improves the extraction rate of cyrtomium fortunei natural dye by exploring and improving the extraction process conditions, one is by using a mixed solvent with a specific composition as an extracting agent, and the other is by introducing a specific kind of clay as an extraction aid; furthermore, comparing the extraction yields of example 5 with those of examples 8-13, it is also well demonstrated that the use of both organobentonite and attapulgite as extraction aids indeed produce a synergistic effect.

Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the compounds, compositions, and methods described herein.

Various modifications and changes can be made to the compounds, compositions, and methods described herein. Other aspects of the compounds, compositions, and methods described herein will be apparent from consideration of the specification and practice of the compounds, compositions, and methods disclosed herein. It is intended that the specification and examples be considered as exemplary.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A method for extracting a rhizoma Cyrtomii Falcati natural dye is characterized by comprising the following steps:

1) removing impurities from rhizoma Osmundae, cleaning, air drying, pulverizing into 80-150 mesh powder, adding into the extractant, soaking, adding pH regulator after rhizoma Osmundae is sufficiently wetted, and regulating pH of the solution to 9-14; then adding extraction auxiliary agent, heating the solution to 60-100 deg.C, keeping the temperature for about 60-180min, and filtering; repeatedly extracting for 3-5 times, mixing the leaching solutions obtained many times to obtain natural dye stock solution;

2) decompressing and concentrating the natural dye stock solution obtained in the step 1), and then freeze-drying to obtain powdery natural dye;

wherein the extraction auxiliary agent is a mixture of bentonite and attapulgite, wherein the content of the bentonite is 30-50 wt.%; the addition amount is 5-30g/L, and the volume of the solution is taken as a reference;

the extractant is a mixed solvent of ethanol and water, the volume content of the ethanol is 50-80 v.%, and the total volume of the mixed solvent is taken as a reference;

the material ratio in the step 1), namely the weight of the cyrtomium fortunei raw material added into the extracting agent/(the weight of the solution obtained after the extracting agent and the cyrtomium fortunei raw material are mixed) is 1: 10-1: 50.

2. the extraction method of claim 1, wherein the pH regulator is hydroxide, carbonate, silicate and/or phosphate of alkali metal.

3. The extraction process according to claim 1, wherein the bentonite is present in an amount of 35-45 wt.%.

4. The extraction method according to claim 3, wherein the bentonite is sodium bentonite and/or organic bentonite.

5. The extraction method as claimed in claim 1, wherein the pulverized rhizoma Osmundae material in step 1) has a particle size of 100-130 meshes; the pH value of the solution is 10-13; the temperature during leaching is 70-90 ℃; the leaching time is 80-160 min; the number of extraction times was 4.