Natural pigment composition and preparation method thereof

Abstract

The invention discloses a natural pigment composition and a preparation method thereof, and belongs to the technical field of pigments, the natural pigment composition comprises the following raw materials: a first pigment, a second pigment, a complexing agent and / or a coating framework material, the first pigment is a tea pigment, and the second pigment is one or more of curcumine, sunflower yellow pigment and safflower yellow. The invention also provides a preparation method of the natural pigment composition, which comprises the following steps: dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution; adding a complexing agent into the first mixed solution, and carrying out a complexing reaction to obtain a second solution; adding a coating framework material into the second solution, and carrying out oscillation reaction at 25-30 DEG C for 10-12 hours to obtain a third solution; and freeze-drying the third solution to obtain the natural pigment composition. The natural pigment composition disclosed by the invention is good in dyeing property and excellent in color fixing property.

Description

Technical Field

[0001] The invention relates to the technical field of pigments, and in particular to a natural pigment composition and a preparation method thereof. Background Art

[0002] Cellulose fibers include natural cellulose fibers and regenerated cellulose fibers. Natural cellulose fibers are directly taken from plant tissues without chemical treatment. The raw materials are generally spun and manufactured by mechanical methods and processed into shaped cloth. The most common ones are cotton and linen. Later, new natural cellulose fibers have also been launched, such as bamboo fiber and kapok fiber. Regenerated cellulose fibers use natural cellulose as raw material. During the manufacturing process, cellulose is converted into a soluble cellulose derivative, which is then extruded through a spinneret and enters a chemical bath, where it hardens into fibers. This method is also called wet spinning.

[0003] Natural plant dyes are green, environmentally friendly and harmless to the human body. Dyeing cellulose fabrics with natural dyes can not only give the product extremely high added value, but also meet people's requirements for pure natural clothing fabrics. However, the molecular structure of most natural dyes contains carboxyl, hydroxyl and other groups, which makes the pigments highly water-soluble, while the fiber surface lacks groups that can stably bind to the dyes. When dyeing on the fiber, the pigments tend to accumulate on the fiber surface, and most of them are mainly bound by van der Waals forces and hydrogen bonds, and the ability to diffuse into the fiber is small, the dyeing rate is low, and the color fastness is poor.

[0004] Natural pigments are commonly used in the field of dyeing cotton and linen textiles. They are loved by people for their natural coloring and rich colors. In the prior art, when natural pigments are used to dye cotton, linen and other textiles, technical problems such as coloring difficulty and poor color fastness will occur. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a natural pigment composition and a preparation method thereof, and solve the technical problems in the prior art that natural pigments are difficult to color and have poor color fastness.

[0006] In order to achieve the above technical purpose, the technical solution of the present invention provides a natural pigment composition, the raw materials of which include a first pigment, a second pigment, a complexing agent and / or a coating skeleton material, the first pigment is a tea pigment, and the second pigment is one or more of curcumin, sunflower yellow pigment, and safflower yellow pigment. The tea pigment in the present invention can be a tea pigment extracted from tea leaves such as green tea and black tea by alcohol extraction.

[0007] Preferably, the complexing agent is lanthanum chloride and ferric chloride, and the mass ratio of the two is 1:0.6-1.1, specifically 1:0.8, 1:1, etc., and the coating framework material is a metal organic framework material.

[0008] Preferably, the coating framework material is a zeolite imidazolate framework material.

[0009] Preferably, the pore size of the zeolite imidazolate framework material is 3-5 nm.

[0010] Preferably, the raw materials include 1-1.5 parts of the first pigment, 1.5-2.5 parts of the second pigment, 4-6 parts of the complexing agent, and 1.5-2 parts of the coating skeleton material in parts by mass.

[0011] A method for preparing the natural pigment composition described above comprises the following steps:

[0012] S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution;

[0013] S2, adding a complexing agent to the first mixed solution to carry out a complexing reaction to obtain a second solution;

[0014] S3, adding the coated skeleton material to the second solution and shaking for reaction at 25-30° C. for 10-12 hours to obtain a third solution;

[0015] S4, freeze-drying the third solution to obtain the natural pigment composition.

[0016] Preferably, the solute concentration of the first mixed solution in S1 is 2.5-4 g / L.

[0017] Preferably, the reaction temperature of the complexation reaction in S2 is 60-70°C.

[0018] An application of the above-mentioned natural pigment composition in textile dyeing comprises the following steps:

[0019] (1) mixing β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water, and reacting to obtain a modified solution;

[0020] (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to a solution bath ratio of 1:50-60, and obtaining the modified fabric after drying;

[0021] (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 15-18 g / L;

[0022] (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:40-50, and obtaining the dyed fabric after drying.

[0023] Preferably, the concentrations of β-cyclodextrin, chitosan, sodium hypophosphite and citric acid in the modified solution are 70-90 g / L, 40-60 g / L, 20-40 g / L and 50-70 g / L, respectively.

[0024] Preferably, the drying temperature is 70-80°C.

[0025] The lanthanum chloride in the natural pigment composition of the present invention is complexed with the phenolic hydroxyl groups in the first pigment and the second pigment (the tea pigment, curcumin, sunflower yellow pigment, and safflower yellow pigment all contain phenolic hydroxyl groups). The rare earth ion as the central ion has a strong complexation with the ligand containing the lone pair electron group, and acts as a cross-linking agent in the amorphous region of the fiber by means of the combination of coordination bonds and covalent bonds, so that the absorption peak of the dye molecule moves to the long wave, resulting in color change and deepening, and can provide the K / S value of the dyed silk fabric. In addition, the natural pigment composition can be applied to the process of textile dyeing to La 3+ It chelates with phenolic hydroxyl groups and amino and carboxyl groups on the fiber surface to improve the colorability of the pigment.

[0026] Ferric chloride (FeCl3) forms strong coordination bonds with multi-electron donor functional groups such as hydroxyl and carboxyl groups in pigment molecules by releasing trivalent Fe ions to achieve complexation. This process significantly improves the stability of pigments in different environments, improves the color fastness of the pigment dyeing process, and makes the color more durable and less susceptible to washing and friction.

[0027] At the same time, La 3+ and Fe 3+ As a complexing substance, La 3+ and Fe 3+ In the complexation, different coordination numbers and coordination geometries are exhibited, and this complementary effect can further enhance the structural stability and performance of the complex. 3+ Usually forms octahedral or tetragonal coordination, while Fe 3+ Different coordination structures can cover more types of pigment functional groups, enhance the overall complexing ability and improve the color fastness of the pigment.

[0028] At the same time, the present invention uses zeolite imidazolate skeleton material as the coating material for modifying pigments with lanthanum chloride and ferric chloride. Zeolite imidazolate skeleton material has a high surface area and a highly ordered pore structure, which can effectively coat and protect natural pigment molecules. This coating can provide a physical barrier to prevent the pigment molecules from being affected by environmental factors such as light, heat, and oxygen, thereby improving the stability and durability of the pigment. At the same time, this coating will not affect the color release behavior of the pigment; this type of material has good surface chemical properties and dispersibility, and can effectively and evenly disperse the pigment molecules. In applications such as textile dyeing, good dispersibility can ensure uniform dyeing and avoid color spots and color difference problems. The coating of zeolite imidazolate skeleton material can significantly improve the color fastness of the pigment and prevent the dyed textiles from fading under conditions such as washing, friction, and light. This not only improves the aesthetics of the textiles, but also extends their service life.

[0029] Pigment molecules in natural pigments (such as tea pigments, curcumin, etc.) usually contain multiple active groups such as hydroxyl, carboxyl, and phenolic hydroxyl groups, which can react with lanthanum ions or Fe 3+ The coordination bonds form complexes. The stability of the complexes formed is significantly improved due to the presence of coordination bonds, and they can resist the erosion of external environmental factors (such as light, heat, and oxidants).

[0030] After the complexation reaction is completed, it is coated with a zeolite imidazolate skeleton material. The zeolite imidazolate skeleton material has a highly ordered nanopore structure, and these pores can accurately and selectively adsorb the already complexed pigment molecules. Due to the complexation reaction, the size and surface charge of the color molecules change, which increases the adsorption advantage in specific pores. The coated pigment molecules are confined in the nanopores of the zeolite imidazolate skeleton material, forming a physical barrier, reducing the direct contact between the pigment molecules and the external environment, thereby enhancing their light resistance and antioxidant ability, and achieving improved color fixation.

[0031] The formation of the complex enhances the stability and coloring properties of the pigment molecules, while the coating provides an additional physical barrier, reducing the loss and decomposition of the pigment molecules during use, thereby significantly improving the coloring fastness.

[0032] When the natural pigment composition of the present invention is applied to cotton, linen and other fabrics, β-cyclodextrin and chitosan can be added to the fabric to be dyed for modification and finishing.

[0033] β-cyclodextrin has certain similarities with the cellulose molecules of textiles. They have the same structural unit glucose, connecting bond α-1.4 glycosidic bond and active functional group hydroxyl. At the same time, the fabric modified by β-cyclodextrin has an inclusion effect on curcumin, sunflower yellow and safflower yellow. Here, β-cyclodextrin is equivalent to playing a bridging role. β-cyclodextrin is first grafted on the surface of the textile and then dyed. The groups of β-cyclodextrin will adsorb the pigment molecules through inclusion and enhance the colorability of the pigment.

[0034] During dyeing, the tea polyphenols in the tea pigment and the chitosan on the fabric are bonded to each other by ionic bonds, and the bond energy is stronger than the van der Waals force, which can improve the dyeing rate of the pigment. At the same time, the electrostatic attraction between the dye anion and the protonated amino group of chitosan can also improve the dyeing rate of the dye. On the other hand, chitosan penetrates into the fiber, and when the pigment is combined, the pigment will also enter the fiber, further preventing the pigment from swelling, dissolving and falling off during the fastness test and wearing process, and improving the friction fastness of the pigment.

[0035] β-cyclodextrin effectively encapsulates natural pigment molecules through its hydrophilic outer wall and hydrophobic inner cavity, improving its solubility and dispersibility. The amino group in chitosan can form a coordination bond with the carboxyl or phenolic hydroxyl group on the dye molecule, enhancing the binding force between the pigment and the fiber. β-cyclodextrin provides an inclusion space to protect natural pigments and prevent pigment molecules from being directly affected by the external environment (such as light, oxidants, etc.); while chitosan forms a protective layer on the fiber surface, further enhancing the adhesion and stability of the pigment. The two work together to further improve the colorability and fastness of the pigment.

[0036] Compared with the prior art, the beneficial effects of the present invention include:

[0037] 1. The lanthanum chloride and ferric chloride in the natural pigment composition of the present invention are complexed with the phenolic hydroxyl group and carboxyl group in the first pigment and the second pigment, and chelated with the amino group and carboxyl group on the fiber surface, thereby improving the coloring property of the pigment;

[0038] 2. After complexation, the pigment molecules are coated and confined in the nanopores of the zeolite imidazolate framework material, forming a physical barrier, reducing the direct contact between the pigment molecules and the external environment, thereby enhancing the light resistance and antioxidant ability of the pigment and improving the color fixation;

[0039] 3. During the application process, the pigment composition of the present invention is first modified and finished on the textile to be treated. β-cyclodextrin and chitosan are first grafted onto the textile to be dyed. During the dyeing process, the dye anions and the protonated amino groups of chitosan are attracted by electrostatic attraction, and the pigment molecules also undergo inclusion reaction with β-cyclodextrin to achieve rapid coloring of the pigment.

[0040] 4. The pigment in the present invention is pre-treated by first complexing and then coating to improve the coloring and color fixation of the pigment. During the dyeing process, the active substances on the pigment molecules can be quickly and tightly combined with the finished textile. The preparation method of the present invention is simple, green and pollution-free. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] The preparation method of the zeolite imidazolate framework material of the present invention comprises the following steps: dissolving 0.5-2.5 parts of zinc nitrate and 2-4 parts of dimethyl imidazole in anhydrous methanol respectively by weight, mixing and stirring to obtain a suspended liquid; centrifuging to obtain a precipitate; washing with methanol, drying and grinding the washed precipitate to obtain the zeolite imidazolate framework material.

[0043] The raw materials used in the following examples were obtained as follows:

[0044] The method for obtaining green tea pigment is as follows: drying green tea leaves at 50°C to constant weight, and then crushing the tea leaves into powder with a particle size of less than 100 microns; adding the tea powder to 75wt% ethanol, with the mass ratio of the two being 1:10; extracting at 70°C for 2h, filtering to obtain an alcohol extraction solution; volatilizing the ethanol solvent at 45°C until the solvent is completely volatilized to obtain tea pigment.

[0045] Theabrownin is alcohol-extracted theabrownin with a purity of 40% and sold by Shaanxi Ronglin Biotechnology Co., Ltd.

[0046] The zeolite imidazolate framework material is prepared in the laboratory. The preparation process is as follows: 1.5 parts of zinc nitrate and 3.32 parts of dimethyl imidazole are fully dissolved in 70 parts of anhydrous methanol, respectively, and then the two are mixed, stirred at 200rpm for 24 hours under normal pressure and 25°C, to obtain a milky white suspension liquid, the liquid is poured into a centrifuge tube and placed in a centrifuge for 5 minutes at 8500rpm / min to obtain a milky white crystal precipitate, and methanol is poured into the precipitate for washing. The above steps are repeated three times to obtain a washed milky white crystal precipitate, which is placed in a vacuum drying oven at 70°C for 24 hours, and the dried reactant is taken out and placed in a mortar for full grinding to obtain the final product. The zeolite imidazolate framework material can be prepared according to the amount used.

[0047] Example 1

[0048] The present embodiment provides a natural pigment composition, whose raw materials include, by mass, 1 part of a first pigment, 1.5 parts of a second pigment, 2 parts of lanthanum chloride, 2 parts of ferric chloride, and 1.5 parts of a zeolite imidazolate framework material, wherein the pore size of the zeolite imidazolate framework material is 3 nm, the first pigment is a green tea pigment, and the second pigment is curcumin.

[0049] A method for preparing the natural pigment composition described above comprises the following steps:

[0050] S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution with a solute concentration of 2.5 g / L;

[0051] S2, adding lanthanum chloride and ferric chloride as complexing agents to the first mixed solution for complexing reaction at 60° C. for 40 min to obtain a second solution;

[0052] S3, adding the coated framework material zeolite imidazolate framework material to the second solution and shaking for reaction at 25° C. for 10 hours to obtain a third solution;

[0053] S4. Freeze-drying the third solution at -10°C until the water content is 2% to obtain the natural pigment composition.

[0054] An application of the natural pigment composition as described above in textile dyeing comprises the following steps:

[0055] (1) β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water are mixed to obtain a modified solution after reaction, wherein the concentrations of β-cyclodextrin, chitosan, sodium hypophosphite and citric acid in the modified solution are 80 g / L, 50 g / L, 30 g / L and 60 g / L respectively;

[0056] (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to a solution bath ratio of 1:50, soaking for 1 hour, at a temperature of 80° C., and drying at 120° C. for 10 minutes to obtain the modified fabric;

[0057] (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 15 g / L;

[0058] (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:40, dyeing temperature of 80° C., dyeing time of 50 min, and drying at 70° C. for 4 h to obtain the dyed fabric.

[0059] Example 2

[0060] The present embodiment provides a natural pigment composition, whose raw materials include, by mass, 1.5 parts of a first pigment, 2.5 parts of a second pigment, 3 parts of lanthanum chloride, 3 parts of ferric chloride, and 2 parts of a zeolite imidazolate framework material, wherein the pore size of the zeolite imidazolate framework material is 5 nm, the first pigment is theabrownin, and the second pigment is sunflower yellow pigment.

[0061] A method for preparing the natural pigment composition described above comprises the following steps:

[0062] S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution with a solute concentration of 4 g / L;

[0063] S2, adding lanthanum chloride and ferric chloride as complexing agents to the first mixed solution for complexing reaction at 70° C. for 40 min to obtain a second solution;

[0064] S3, adding the coated skeleton material to the second solution and shaking for 12 hours at 30° C. to obtain a third solution;

[0065] S4. Freeze-drying the third solution at -10°C until the water content is 2% to obtain the natural pigment composition.

[0066] An application of the natural pigment composition as described above in textile dyeing comprises the following steps:

[0067] (1) β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water are mixed to obtain a modified solution after reaction, wherein the concentrations of β-cyclodextrin, chitosan, sodium hypophosphite and citric acid in the modified solution are 80 g / L, 50 g / L, 30 g / L and 60 g / L respectively;

[0068] (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to a solution bath ratio of 1:60, soaking for 1 hour, at a temperature of 80° C., and drying at 130° C. for 10 minutes to obtain the modified fabric;

[0069] (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 18 g / L;

[0070] (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:50, the dyeing temperature being 80° C., the dyeing time being 50 min, and drying at 80° C. for 3 h to obtain the dyed fabric.

[0071] Example 3

[0072] The present embodiment provides a natural pigment composition, whose raw materials include, by mass, 1.2 parts of a first pigment, 2 parts of a second pigment, 2.5 parts of lanthanum chloride, 2.5 parts of ferric chloride, and 1.8 parts of a zeolite imidazolate framework material, wherein the pore size of the zeolite imidazolate framework material is 4 nm, the first pigment is a green tea pigment, and the second pigment is a safflower yellow pigment.

[0073] A method for preparing the natural pigment composition described above comprises the following steps:

[0074] S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution with a solute concentration of 3 g / L;

[0075] S2, adding lanthanum chloride and ferric chloride as complexing agents to the first mixed solution for complexing reaction at 65° C. for 40 min to obtain a second solution;

[0076] S3, adding the coated skeleton material to the second solution and shaking for 11 hours at 28° C. to obtain a third solution;

[0077] S4. Freeze-drying the third solution at -10°C until the water content is 2% to obtain the natural pigment composition.

[0078] An application of the natural pigment composition as described above in textile dyeing comprises the following steps:

[0079] (1) β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water are mixed to obtain a modified solution after reaction, wherein the concentrations of β-cyclodextrin, chitosan, sodium hypophosphite and citric acid in the modified solution are 80 g / L, 50 g / L, 30 g / L and 60 g / L respectively;

[0080] (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to the solution bath ratio of 1:55, soaking for 1 hour, at a temperature of 80° C., and drying at 125° C. for 10 minutes to obtain the modified fabric;

[0081] (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 16 g / L;

[0082] (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:45, dyeing temperature of 80° C., dyeing time of 50 min, and drying at 75° C. for 3.5 h to obtain the dyed fabric.

[0083] Example 4

[0084] The present embodiment provides a natural pigment composition, whose raw materials include, by mass, 1.5 parts of a first pigment, 2.5 parts of a second pigment, 2 parts of lanthanum chloride, 2 parts of ferric chloride, and 1.7 parts of a zeolite imidazolate framework material, wherein the pore size of the zeolite imidazolate framework material is 5 nm, the first pigment is a green tea pigment, and the second pigment is curcumin.

[0085] A method for preparing the natural pigment composition described above comprises the following steps:

[0086] S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution with a solute concentration of 4 g / L;

[0087] S2, adding lanthanum chloride and ferric chloride as complexing agents to the first mixed solution for complexing reaction at 60° C. for 40 min to obtain a second solution;

[0088] S3, adding the coated skeleton material to the second solution and shaking for 12 hours at 25° C. to obtain a third solution;

[0089] S4. Freeze-drying the third solution at -10°C until the water content is 2% to obtain the natural pigment composition.

[0090] An application of the natural pigment composition as described above in textile dyeing comprises the following steps:

[0091] (1) β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water are mixed to obtain a modified solution after reaction, wherein the concentrations of β-cyclodextrin, chitosan, sodium hypophosphite and citric acid in the modified solution are 80 g / L, 50 g / L, 30 g / L and 60 g / L respectively;

[0092] (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to a solution bath ratio of 1:50, soaking for 1 hour, at a temperature of 80° C., and drying at 120° C. for 10 minutes to obtain the modified fabric;

[0093] (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 15 g / L;

[0094] (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:40, the dyeing temperature being 80° C., the dyeing time being 50 min, and drying at 80° C. for 3 h to obtain the dyed fabric.

[0095] Comparative Example 1

[0096] This comparative example is similar to Example 1, except that in this comparative example, an equal amount of β-cyclodextrin is replaced by chitosan during the application of the natural pigment composition in textile dyeing.

[0097] Comparative Example 2

[0098] This comparative example is similar to Example 1, except that in this comparative example, an equal amount of chitosan is replaced by β-cyclodextrin during the application of the natural pigment composition in textile dyeing.

[0099] Comparative Example 3

[0100] This comparative example is similar to Example 1, except that in this comparative example, no zeolite imidazolate framework material is added to the natural pigment composition, and step S3 is not included in the preparation method of the natural pigment composition.

[0101] Comparative Example 4

[0102] This comparative example is similar to Example 1, except that in this comparative example, an equal amount of lanthanum chloride is replaced by ferric chloride in the natural pigment composition, and the ferric chloride is 4 parts.

[0103] Comparative Example 5

[0104] This comparative example is similar to Example 1, except that in this comparative example, an equal amount of ferric chloride in the natural pigment composition is replaced by 4 parts of lanthanum chloride.

[0105] The color fastness and color fixation of the natural pigment compositions in Examples 1-4 and Comparative Examples 1-5 during their application were tested, and the relevant test results are shown in Table 1, wherein the K / S value of each fabric was measured by evenly taking 8 points on the fabric using a Datacolor-600 spectrophotometer; the color fastness to rubbing was measured in accordance with GB / T3920-2008 "Textiles - Tests for Color Fastness - Fastness to Rubbing"; the color fastness to washing was measured in accordance with GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Soaping: Test 1"; the color fastness to sunlight was measured in accordance with GB / T8427-2008 "Textiles - Tests for Color Fastness - Color Fastness to Artificial Light - Arc: Xenon Arc".

[0106] Table 1 Test results of coloring and color fixation properties of natural pigment compositions

[0107]

[0108]

[0109] The data in the above table show that the addition of β-cyclodextrin and chitosan has a significant effect on the coloring and color fixation of the pigment; the zeolite imidazolate framework material has a significant effect on improving the color fixation of the pigment; at the same time, the addition of lanthanum chloride and ferric chloride has a better effect on the coloring of the pigment.

[0110] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A natural pigment composition, characterized in that The raw materials include a first pigment, a second pigment, a complexing agent and / or a coating skeleton material. The first pigment is tea pigment, and the second pigment is one or more of curcumin, sunflower yellow and safflower yellow.

2. The natural pigment composition according to claim 1, characterized in that The complexing agent is lanthanum chloride and ferric chloride, and the coating framework material is a metal organic framework material.

3. The natural pigment composition according to claim 2, characterized in that The coating framework material is a zeolite imidazolate framework material.

4. The natural pigment composition according to claim 1, characterized in that The raw materials include 1-1.5 parts of the first pigment, 1.5-2.5 parts of the second pigment, 4-6 parts of the complexing agent and 1.5-2 parts of the coating skeleton material by weight.

5. The natural pigment composition according to claim 1, characterized in that The mass ratio of lanthanum chloride to ferric chloride is 1:0.6-1.

1.

6. A method for preparing the natural pigment composition according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, dissolving the first pigment and the second pigment in deionized water to obtain a first mixed solution; S2, adding a complexing agent to the first mixed solution to carry out a complexing reaction to obtain a second solution; S3, adding the coated skeleton material to the second solution and shaking for reaction at 25-30° C. for 10-12 hours to obtain a third solution; S4, freeze-drying the third solution to obtain the natural pigment composition.

7. The method according to claim 6, characterized in that The solute concentration of the first mixed solution in S1 is 2.5-4 g / L.

8. The method according to claim 6, characterized in that The reaction temperature of the complexation reaction in S2 is 60-70°C.

9. Use of the natural pigment composition according to any one of claims 1 to 5 in textile dyeing, characterized in that: The following steps are involved: (1) mixing β-cyclodextrin, chitosan, sodium hypophosphite, citric acid and water, and reacting to obtain a modified solution; (2) placing the fabric to be dyed into the modified solution, modifying the fabric according to a solution bath ratio of 1:50-60, and obtaining the modified fabric after drying; (3) dissolving the natural pigment composition in deionized water to prepare a dyeing solution with a solute concentration of 15-18 g / L; (4) placing the modified fabric into the dyeing solution, dyeing the fabric according to a solution bath ratio of 1:40-50, dyeing the fabric at a temperature of 80-85° C. for 40-50 min, and drying to obtain the dyed fabric.

10. The use according to claim 9, characterized in that: The drying temperature is 70-80°C.

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