Mixed color structure yarn dyed fabric and preparation method thereof

Abstract

The invention discloses a preparation method of a mixed color structure yarn-dyed fabric, which comprises the following steps: completely dissolving caffeic acid in deionized water, then adding a potassium iodate solution, stirring for reaction, centrifuging and washing to obtain poly caffeic acid nano microspheres; repeating the steps, and changing the conditions of caffeic acid and potassium iodate to obtain poly-caffeic acid nano-microspheres with different particle sizes; respectively dispersing the poly-caffeic acid nano-microspheres with different particle sizes in water to obtain microsphere dispersion liquids with different particle sizes; uniformly mixing the microsphere dispersion liquids with different particle sizes to obtain a mixed dispersion liquid, and then adding waterborne polyurethane to obtain a microsphere assembly liquid; and immersing the fabric in the microsphere assembly liquid, and carrying out self-assembly to obtain the mixed color structure yarn-dyed fabric. According to the preparation method disclosed by the invention, the poly-caffeic acid nano-microspheres with different particle sizes are mixed and deposited, so that fabrics with various structural colors can be rapidly prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of structural color, and particularly to a preparation method of a mixed-color structural color fabric and a mixed-color structural color fabric prepared by using the preparation method. Background Art

[0002] Structural color is generated by the physical interaction between light and specific periodic microstructures or nanostructures in materials, involving phenomena such as interference, diffraction, and scattering, and has the characteristics of environmental protection, bright colors, and never fading.

[0003] In recent years, microsphere self-assembly has become one of the most commonly used methods for constructing structural color fabrics due to its high controllability during the assembly process and the excellent optical properties of the assembled structures. In order to achieve a bright color decoration effect, researchers have been actively developing full-spectrum photonic crystal structural colors.

[0004] The main method currently adopted is to use nano-microspheres of different sizes to construct photonic crystals with different photonic bandgaps, thereby generating a series of structural colors (such as patent application numbers 202211404041.8 and 202411378179.4). However, producing each structural color requires microspheres of precise sizes, which makes the process more complex. In addition, some studies have obtained inspiration from the additive mixing of chemical colors and selected poly(styrene-methyl methacrylate) microspheres of three different sizes (234 nm, 178 nm, 152 nm) to represent the three primary colors (red, green, blue) (reference: Surf. Interfaces, 2024, 51, 104805). These microspheres are mixed in pairs and sprayed onto a dark wood substrate in different proportions to obtain uniform structural colors that almost cover the entire visible spectrum, thus expanding the potential application of mixed microsphere assembly in the field of structural color generation. However, due to the influence of incoherent scattered light, it is still a challenge to obtain high-saturation mixed-color structural colors on white fabrics.

[0005] When using the most common white fabric as the substrate, the structural colors obtained by commonly used microspheres such as polystyrene and silica microspheres usually appear white, and it is necessary to introduce black light-absorbing substances to absorb incoherent scattered light (such as carbon powder, graphene). The addition of these additional substances is likely to reduce the uniformity of the structural color, and the amount introduced will affect the saturation of the structural color. Therefore, it is difficult to obtain bright structural colors only by dark microspheres on the surface of white fabrics.

[0006] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available before the filing date of this patent application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] In view of this, in order to overcome the defects of the prior art, the object of the present invention is to provide a preparation method of a mixed-color structural color fabric.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A preparation method of a mixed-color structural color fabric includes the following steps:

[0010] Completely dissolve caffeic acid in deionized water, then add potassium iodate solution, stir and react, and after centrifugation and washing with water, obtain polycaffeic acid nano-microspheres;

[0011] Repeat the above steps, change the conditions of caffeic acid and potassium iodate to obtain polycaffeic acid nano-microspheres with different particle sizes;

[0012] Disperse the polycaffeic acid nano-microspheres with different particle sizes in water respectively to obtain microsphere dispersion liquids with different particle sizes;

[0013] Mix two microsphere dispersion liquids with different particle sizes evenly to obtain a mixed dispersion liquid, and then add waterborne polyurethane to obtain a microsphere assembly liquid;

[0014] Immerse the fabric in the microsphere assembly liquid and obtain a mixed-color structural color fabric after self-assembly.

[0015] Compared with the coated microspheres, the preparation process of directly preparing polycaffeic acid nano-microspheres from caffeic acid and potassium iodate in the present invention only requires one-step polymerization, and the operation is simple and convenient. Moreover, it mainly uses green natural phenolic acid polycaffeic acid as the raw material, without involving the use of styrene or silica, etc., and is more environmentally friendly.

[0016] According to some preferred embodiments of the present invention, the condition of changing caffeic acid and potassium iodate is: fixing the concentration ratio of potassium iodate to caffeic acid and increasing the concentration of caffeic acid, and the particle size of the polycaffeic acid microspheres increases.

[0017] According to some preferred embodiments of the present invention, the condition of changing caffeic acid and potassium iodate is: fixing the concentration of caffeic acid and increasing the concentration ratio of potassium iodate to caffeic acid, and the particle size of the polycaffeic acid microspheres first increases and then decreases. Specifically, when the concentration ratio of potassium iodate to caffeic acid is in the range of 0.2:1 to 0.7:1, the particle size gradually increases, and when it is in the range of 0.7:1 to 3:1, the particle size gradually decreases.

[0018] According to some preferred embodiments of the present invention, the concentration of caffeic acid is 4 - 15 mmol / L.

[0019] According to some preferred embodiments of the present invention, the concentration ratio of potassium iodate to caffeic acid is 0.2:1 - 3:1.

[0020] According to some preferred embodiments of the present invention, the reaction temperature of the stirring reaction is 50 - 100 °C, and the reaction time is 1 - 6 h.

[0021] According to some preferred embodiments of the present invention, the particle size of the polycaffeic acid microspheres is 150 - 300 nm.

[0022] According to some preferred embodiments of the present invention, the mass fraction of the microsphere dispersion is 3% - 10%.

[0023] According to some preferred embodiments of the present invention, when the mixed dispersion contains two different particle sizes of polycaffeic acid nano - microspheres, the volume ratio between the microsphere dispersion of the polycaffeic acid nano - microspheres with a smaller particle size and the microsphere dispersion of the polycaffeic acid nano - microspheres with a larger particle size is 0.3:1 - 5:1. Preferably, microspheres with two different particle sizes and different color systems are mixed. If three particle sizes are mixed, the degree of chaos is too high to produce structural color. At the same time, the intermediate color formed by mixing microspheres with two different particle sizes and different color systems is called a mixed color.

[0024] According to some preferred embodiments of the present invention, it is preferred that the particle size difference between the two different particle sizes of polycaffeic acid nano - microspheres is more than 20 nm, so that more abundant colors can be formed after the two different particle sizes of polycaffeic acid nano - microspheres are compounded in different proportions, avoiding the situation where the difference between the two primary colors is too small to achieve the mixed - color effect.

[0025] According to some preferred embodiments of the present invention, the addition amount of the aqueous polyurethane is 5% - 20% of the total mass of the microsphere assembly liquid.

[0026] According to some preferred embodiments of the present invention, the conditions for self - assembly are gravity self - assembly at 40 - 90 °C for 1 - 5 h.

[0027] According to some preferred embodiments of the present invention, the material of the fabric is wool, silk, cotton, polyester or nylon.

[0028] In some embodiments of the present invention, the preparation method of the mixed - color structural - color fabric specifically includes the following steps:

[0029] Step S1: Completely dissolve caffeic acid in deionized water, then add potassium iodate solution, stir and react. After centrifugation and washing with water, polycaffeic acid nano - microspheres with corresponding particle sizes are obtained.

[0030] Repeat step S1 and change the concentration of caffeic acid or the concentration ratio of potassium iodate to caffeic acid to obtain polycaffeic acid nano - microspheres with different particle sizes. Specifically, under the condition of fixing the concentration ratio of potassium iodate to caffeic acid, the particle size of polycaffeic acid microspheres increases with the increase of caffeic acid concentration. Under the condition of fixing the caffeic acid concentration, the particle size of polycaffeic acid microspheres first increases and then decreases with the increase of the concentration ratio of potassium iodate to caffeic acid.

[0031] Step S2: Disperse the polycaffeic acid nano - microspheres with different particle sizes in water respectively to obtain microsphere dispersion liquids with different particle sizes. The mass fraction of the microsphere dispersion liquid is 3% - 10%.

[0032] Step S3: Mix two polycaffeic acid nano - microsphere dispersion liquids with different particle sizes according to a certain volume ratio to obtain a mixed dispersion liquid. Then add water - borne polyurethane to obtain a microsphere assembly liquid.

[0033] Step S4: Immerse the fabric in the microsphere assembly liquid and perform gravity self - assembly at 40 - 90 °C for 1 - 5 h to obtain a fabric with a mixed structural color.

[0034] The present invention also provides a fabric with a mixed structural color prepared according to the above - mentioned preparation method.

[0035] Compared with the existing traditional technologies, the beneficial effects of the present invention are as follows: In the preparation method of the fabric with a mixed structural color of the present invention, the use of polycaffeic acid nano - microspheres with different particle sizes for mixed deposition can quickly prepare fabrics with various structural colors. At the same time, the excellent light - absorbing characteristics of polycaffeic acid nano - microspheres avoid the influence of incoherent scattered light in the microsphere assembly structure, and bright structural colors can be constructed on the surface of white fabrics without the need for additional black additives. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is the reflection spectrum of three mixed - structural - color fabrics prepared in Example 1 of the present invention;

[0038] Figure 2 It is the scanning electron microscope pictures of the surfaces of three - color fabrics prepared in Example 1 of the present invention;

[0039] Figure 3 It is the reflection spectrum of three mixed - structural - color fabrics prepared in Example 2 of the present invention. Detailed Embodiments

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The preparation method of the color-mixed structural color fabric of the present invention uses polycaffeic acid nano-microspheres with different particle sizes for mixed deposition, and can quickly prepare fabrics with various structural colors. The synthesis of polycaffeic acid microspheres is simple in operation and environmentally friendly. At the same time, the excellent light absorption characteristics of polycaffeic acid nano-microspheres avoid the influence of incoherent scattered light in the microsphere assembly structure, thereby improving the color saturation of the structural color, and can solve the problem that it is impossible to quickly obtain a structural color fabric with a complete chromatogram and bright colors in the prior art.

[0042] Specifically, the preparation method of the color-mixed structural color fabric of the present invention includes the following steps:

[0043] Step S1: Completely dissolve caffeic acid in deionized water, then add potassium iodate solution, stir and react, and after centrifugation and washing with water, polycaffeic acid nano-microspheres with corresponding particle sizes are obtained.

[0044] Among them, the concentration of caffeic acid is 4-15 mmol / L; the concentration ratio of potassium iodate to caffeic acid is 0.2:1-3:1; the reaction temperature of the stirring reaction is 50-100 °C, and the reaction time is 1-6 h. The particle size of the prepared polycaffeic acid nano-microspheres is 150-300 nm.

[0045] Repeat step S1 and change the concentration of caffeic acid or the concentration ratio of potassium iodate to caffeic acid to obtain polycaffeic acid nano-microspheres with different particle sizes.

[0046] Specifically, under the condition of fixing the concentration ratio of potassium iodate to caffeic acid, the particle size of polycaffeic acid microspheres increases with the increase of the concentration of caffeic acid. Under the condition of fixing the concentration of caffeic acid, the particle size of polycaffeic acid microspheres first increases and then decreases with the increase of the concentration ratio of potassium iodate to caffeic acid. Specifically, when the concentration ratio of potassium iodate to caffeic acid is in the range of 0.2:1 to 0.7:1, the particle size gradually increases, and when it is in the range of 0.7:1 to 3:1, the particle size gradually decreases.

[0047] Compared with the coated microspheres, the preparation process of directly preparing polycaffeic acid nano-microspheres from caffeic acid and potassium iodate in the present invention only requires one-step polymerization, which is simple and convenient in operation. Moreover, it mainly uses the green natural phenolic acid polycaffeic acid as the raw material, without involving the use of styrene or silica, etc., and is more environmentally friendly.

[0048] Step S2: Disperse polycaffeic acid nanospheres with different particle sizes in water respectively to obtain microsphere dispersions with different particle sizes. The mass fraction of the microsphere dispersion is 3%-10%.

[0049] Step S3: Mix two microsphere dispersions of polycaffeic acid nanospheres with different particle sizes according to a certain volume ratio to obtain a mixed dispersion. Subsequently, add waterborne polyurethane to obtain a microsphere assembly liquid.

[0050] The solid content of the waterborne polyurethane is 15-20%, preferably 16%. The addition amount of the waterborne polyurethane is 5%-20% of the total mass of the microsphere assembly liquid.

[0051] When the mixed dispersion contains two polycaffeic acid nanospheres with different particle sizes, the volume ratio between the microsphere dispersion of the polycaffeic acid nanospheres with a smaller particle size and the microsphere dispersion of the polycaffeic acid nanospheres with a larger particle size is 0.3:1-5:1. Preferably, the particle size difference between the two polycaffeic acid nanospheres with different particle sizes is more than 20 nm, so that richer colors can be formed after the two polycaffeic acid nanospheres with different particle sizes are compounded in different proportions, and the mixing effect cannot be achieved due to too small difference between the two primary colors.

[0052] In the present invention, when two microspheres with different particle sizes are mixed and assembled, the average particle size of the microspheres in the assembled structure changes, so that the maximum reflection wavelength of the structural color fabric changes. Therefore, the color of the mixed-color structural color fabric is determined by the particle size and ratio of the two mixed microspheres, and the color of the mixed-color structural color fabric is the intermediate color of the colors corresponding to the two mixed microspheres. For example, when microspheres with a particle size of 198±10 nm (green) and 256±10 nm (magenta) are mixed and assembled at ratios of 0.3:1, 1:1, and 3:1 respectively, the obtained colors are pink, orange, and yellow.

[0053] Step S4: Immerse the fabric in the microsphere assembly liquid, and perform gravity self-assembly at 40-90°C for 1-5 h to obtain a mixed-color structural color fabric. The material of the fabric is wool, silk, cotton, polyester or nylon.

[0054] Example 1

[0055] The preparation method of the mixed-color structural color fabric in this example includes the following steps:

[0056] 0.936 g of caffeic acid was added to a round-bottom flask containing 630 mL of deionized water, and continuously stirred at 80 °C until completely dissolved. Subsequently, 20 mL of a pre-dissolved potassium iodate solution (1.113 g) was slowly added, and magnetically stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was centrifuged at 8000 rpm / min for 10 min, and then washed three times with deionized water to obtain polycaffeic acid nanospheres with a particle size of 198 ± 10 nm. Similarly, when the amount of caffeic acid was changed to 1.638 g and the amount of potassium iodate was changed to 1.947 g, with other reaction conditions unchanged, polycaffeic acid microspheres with a particle size of 256 ± 10 nm were obtained.

[0057] The above two kinds of microspheres with different particle sizes were ultrasonically dispersed in deionized water to obtain a nanosphere dispersion with a mass fraction of 4%. Subsequently, 1.5 mL, 1 mL, and 0.5 mL of the microsphere dispersion with a particle size of 198 ± 10 nm were respectively mixed with 0.5 mL, 1 mL, and 1.5 mL of the microsphere dispersion with a particle size of 256 ± 10 nm, and 300 μL of an aqueous polyurethane emulsion (solid content 16%) was sequentially added to the three groups of mixed dispersions, and ultrasonically treated for 30 min to make them uniformly mixed to obtain the final mixed assembly solution.

[0058] Then, 2 mL of each of the above three groups of mixed assembly solutions was aspirated and dropped into three petri dishes (diameter 3.5 cm) containing white cotton fabric samples; self-assembled at a constant temperature (80 °C) for 3 h, and structural colors of yellow, orange, and pink could be obtained on the surface of the cotton fabric respectively.

[0059] Furthermore, on different regions of the same fabric, the above three groups of mixed assembly solutions can be used to form structural colors of yellow, orange, and pink. That is, two kinds of microspheres of green (198 ± 10 nm microspheres) and magenta (256 ± 10 nm microspheres) can be mixed in different proportions to obtain a variety of different intermediate colors and applied to the fabric.

[0060] Figure 1 Reflectance spectra of three kinds of mixed structural color fabrics prepared in Example 1 Figure 2 Scanning electron microscope pictures of the surfaces of three kinds of color fabrics prepared in Example 1. It can be seen from Figure 1 that the reflection peaks of the reflectance spectra of the three kinds of mixed-color fabrics are located between green and magenta, indicating that the three colors are intermediate colors of green (198 ± 10 nm microspheres) and magenta (256 ± 10 nm microspheres). Figure 2 The scanning electron microscope pictures show that there are two kinds of microspheres with different particle sizes on the surfaces of the three kinds of mixed-color fabrics, and the proportion of the larger particle size microspheres gradually increases from yellow, orange to pink.

[0061] Example 2

[0062] The preparation method of the color-mixed structural color fabric in this embodiment includes the following steps:

[0063] Add 1.638 g of caffeic acid into a round-bottom flask containing 630 mL of deionized water, and continuously stir at a constant temperature of 80 °C until completely dissolved. Subsequently, slowly add 20 mL of a pre-dissolved potassium iodate solution (1.947 g), and magnetically stir at 80 °C for 3 h. After the reaction is completed, centrifuge the reaction solution at a speed of 8000 rpm / min for 10 min, and then wash it three times with deionized water to obtain polycaffeic acid nanospheres with a particle size of 256 ± 10 nm. Similarly, change the dosage of caffeic acid to 0.585 g and the dosage of potassium iodate to 0.696 g, and keep other reaction conditions unchanged to obtain polycaffeic acid microspheres with a particle size of 154 ± 10 nm.

[0064] Ultrasonically disperse the above two kinds of microspheres with different particle sizes in deionized water to obtain a nanosphere dispersion with a mass fraction of 4%. Subsequently, respectively mix 1.5 mL, 1 mL, and 0.5 mL of the microsphere dispersion with a particle size of 154 ± 10 nm with 0.5 mL, 1 mL, and 1.5 mL of the microsphere dispersion with a particle size of 256 nm, and sequentially add 300 μL of an aqueous polyurethane emulsion (solid content 16%) to the three groups of mixed dispersions, and ultrasonically mix for 30 min to make them uniformly mixed to obtain the final mixed assembly liquid.

[0065] Then suck 2 mL of each of the above three groups of mixed assembly liquids and drop them into three petri dishes (diameter 3.5 cm) containing white cotton fabric samples; self-assemble at a constant temperature (80 °C) for 3 h to obtain structural colors of green, yellowish-green, and light red on the surface of the cotton fabric respectively.

[0066] Figure 3 Figure

[0067] Example 3

[0068] The preparation method of the color-mixed structural color fabric in this embodiment includes the following steps:

[0069] 0.936 g of caffeic acid was added to a round-bottom flask containing 630 mL of deionized water, and continuously stirred at 80 °C until completely dissolved. Subsequently, 20 mL of a pre-dissolved potassium iodate solution (1.113 g) was slowly added, and magnetically stirred at 80 °C for 3 h. After the reaction was completed, the reaction solution was centrifuged at 8000 rpm / min for 10 min, and then washed three times with deionized water to obtain polycaffeic acid nanospheres with a particle size of 198 ± 10 nm. Similarly, when the amount of caffeic acid was changed to 0.585 g and the amount of potassium iodate was changed to 0.696 g, with other reaction conditions remaining unchanged, polycaffeic acid microspheres with a particle size of 154 ± 10 nm were obtained.

[0070] The above two kinds of microspheres with different particle sizes were ultrasonically dispersed in deionized water to obtain a nanosphere dispersion with a mass fraction of 4%. Subsequently, 1.5 mL, 1 mL, and 0.5 mL of the microsphere dispersion with a particle size of 154 ± 10 nm were respectively mixed with 0.5 mL, 1 mL, and 1.5 mL of the microsphere dispersion with a particle size of 198 ± 10 nm, and 300 μL of an aqueous polyurethane emulsion (solid content 16%) was successively added to the three groups of mixed dispersions, and ultrasonically treated for 30 min to make them uniformly mixed to obtain the final mixed assembly solution.

[0071] Then, 2 mL of each of the above three groups of mixed assembly solutions was aspirated and dropped into three petri dishes (diameter 3.5 cm) containing white silk fabric samples; self-assembled at a constant temperature (80 °C) for 3 h, and light blue, cyan, and light green structural colors could be obtained on the silk fabric surface respectively. The three colors were the mixed structural colors of blue (154 ± 10 nm microspheres) and green (198 ± 10 nm microspheres).

[0072] The structural color fabric prepared in Patent CN113106759A uses polystyrene microspheres coated with polycaffeic acid as the building blocks. This kind of microsphere requires two preparation processes during the preparation, with cumbersome steps. One is the synthesis of polystyrene microspheres, and the other is the coating of polycaffeic acid on its surface. Moreover, only six colors can be obtained, and one kind of microsphere with a certain particle size corresponds to one kind of structural color fabric. The preparation process of the polythioresin microspheres used in the examples of Patent CN202310699804.4 is very complicated, and organic solvent acetone is also used. In contrast, the method of the present invention uses polycaffeic acid microspheres directly polymerized from caffeic acid, and the preparation process is simpler and faster. In addition, in the method of the present invention, two or more structural colors can be obtained with two kinds of microspheres with different particle sizes, which can broaden the structural color chromatogram. In the present invention, the preparation process of polycaffeic acid microspheres does not require the addition of organic solvents, only two raw materials, caffeic acid and potassium iodate, and the preparation is simpler and greener.

[0073] The microspheres with different particle sizes in the present invention can be combined in any mixing ratio, and the resulting colors are all different. Mixing green microspheres and red microspheres can obtain many intermediate colors between green and red. It is very difficult to prepare these intermediate colors with microspheres of the same particle size, because microspheres of corresponding particle sizes need to be prepared separately for each color. The particle sizes of the microspheres corresponding to two similar colors may only differ by 1 - 3 nm, which is very difficult to control during the preparation process. Generally, a difference of 10 - 20 nm is relatively easy. Therefore, it is difficult to obtain intermediate colors with similar colors using microspheres of a single particle size in the prior art. However, by using the method in this application, it is very easy to compound and obtain intermediate colors with similar colors, and the operation is simple, green, and environmentally friendly. At the same time, polycaffeic acid microspheres are single-component and simple to synthesize. Without coating polystyrene microspheres, bright structural colors can be constructed on the surface of white fabrics without additional black additives.

[0074] The purpose of the present invention is to prepare a single structural color by mixing microspheres of multiple particle sizes. Fabrics with different structural colors will be obtained after mixing and depositing microspheres of different particle sizes in different proportions. For the preparation method of the color-mixed structural color fabric of the present invention, caffeic acid is completely dissolved in deionized water, and then potassium iodate solution is added. After stirring at an appropriate temperature, polycaffeic acid nano-microspheres are obtained; then, the nano-microsphere dispersions with different particle sizes are mixed in pairs, and aqueous polyurethane is added to obtain a microsphere assembly solution; the fabric is immersed in the microsphere assembly solution, and after gravity self-assembly under appropriate temperature conditions, a color-mixed structural color fabric is obtained. The preparation method provided by the present invention is fast, convenient, and low-cost. The color-mixed structural color fabric prepared has a complete chromatogram and bright colors, effectively broadening the color range of structural color fabrics and having important application value in textile coloring. Compared with the prior art, the caffeic acid used in the present invention has a wide source and good biocompatibility, and is green and environmentally friendly for the preparation of structural color fabrics; polycaffeic acid nano-microspheres have excellent light absorption characteristics, and bright structural colors can be constructed on the surface of white fabrics without additional black additives; the preparation of the color-mixed structural color fabric is simple in operation, easy to control the conditions, and has a high color saturation; the method of the present invention is applicable to a variety of fabrics, including polyester, silk, wool, nylon, etc.

[0075] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and their purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a mixed color structured fabric, characterized in that: It includes the following steps: Completely dissolve caffeic acid in deionized water, then add potassium iodate solution, stir and react, and after centrifugation and washing with water, obtain polycaffeic acid nanospheres; Repeat the above steps, change the conditions of caffeic acid and potassium iodate to obtain polycaffeic acid nanospheres with different particle sizes; Disperse the polycaffeic acid nanospheres with different particle sizes in water respectively to obtain microsphere dispersion liquids with different particle sizes; Mix the microsphere dispersion liquids with different particle sizes evenly to obtain a mixed dispersion liquid, and then add aqueous polyurethane to obtain a microsphere assembly liquid; Immerse the fabric in the microsphere assembly liquid and obtain a multi-color structural color fabric after self-assembly.

2. The preparation method according to claim 1, characterized in that: The conditions for changing caffeic acid and potassium iodate are: fixing the concentration ratio of potassium iodate to caffeic acid and increasing the concentration of caffeic acid, and the particle size of the polycaffeic acid microspheres increases.

3. The preparation method according to claim 1, characterized in that: The conditions for changing caffeic acid and potassium iodate are: fixing the concentration of caffeic acid and increasing the concentration ratio of potassium iodate to caffeic acid, and the particle size of the polycaffeic acid microspheres first increases and then decreases.

4. The preparation method according to claim 1, wherein: The concentration of the caffeic acid is 4 - 15 mmol / L.

5. The preparation method according to claim 1, characterized in that: The concentration ratio of potassium iodate to caffeic acid is 0.2:1 - 3:

1.

6. The preparation method according to claim 1, wherein: The reaction temperature of the stirring reaction is 50 - 100 °C, and the reaction time is 1 - 6 h.

7. The preparation method according to claim 1, wherein: The particle size of the polycaffeic acid microspheres is 150 - 300 nm.

8. The preparation method according to claim 1, characterized in that: The mass fraction of the microsphere dispersion liquid is 3% - 10%.

9. The preparation method according to claim 1, wherein: When the mixed dispersion liquid contains two kinds of polycaffeic acid nanospheres with different particle sizes, the volume ratio between the microsphere dispersion liquid of the polycaffeic acid nanospheres with a smaller particle size and the microsphere dispersion liquid of the polycaffeic acid nanospheres with a larger particle size is 0.3:1 - 5:

1.

10. The preparation method according to claim 1, characterized in that: The addition amount of the aqueous polyurethane is 5% - 20% of the total mass of the microsphere assembly liquid.

11. The preparation method according to claim 1, characterized in that: The conditions for the self-assembly are gravity self-assembly at 40 - 90 °C for 1 - 5 h.

12. The preparation method according to claim 1, characterized in that: The material of the fabric is wool, silk, cotton, polyester or nylon.

13. A multi-color structural color fabric prepared by the preparation method according to any one of claims 1 - 12.

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