Long-acting moisturizing colored leaf as well as preparation method and application thereof

Abstract

The invention provides a long-acting moisturizing colored leaf as well as a preparation method and application thereof, and belongs to the field of biomass materials. According to the method, pigments in natural plants are extracted, mixed with hygroscopic salts and introduced into the decolorized leaves in a vacuumizing mode, and chlorophyll, xanthophyll, rosewood pigments and the like contained in the pigments are water-insoluble substances, so that the color of the subsequently prepared colored leaves cannot be dissolved in water, and the color of the leaves cannot be dissolved in water; therefore, the coating does not fade when encountering water; meanwhile, due to introduction of hygroscopic salts, moisture in the colored leaves can be locked, moisture loss is avoided, moisture in air can be absorbed, and the colored leaves have a long-acting moisturizing effect, so that the colored leaves can be stored indoors for a long time, have good flexibility and are equivalent to new leaves; the problems that natural leaves discolor after being separated from plants, are easy to dry and crisp and are difficult to store are solved.

Description

Technical Field

[0001] The present invention relates to the field of biomass materials, and particularly to a long-acting moisturizing colored leaf and its preparation method and application. Background Art

[0002] Leaves are a natural renewable resource that is very abundant on Earth, and they are highly utilized in the manufacturing of materials and products. Using leaves as materials can reduce people's use of other non-renewable resources such as petroleum and coal. At the same time, leaves can be easily obtained in many places, and the collection cost is relatively low. In addition, due to their beautiful appearance and unique surface structure, they can be used to make various decorative items, fibers and other functional materials. However, while natural leaves have the above advantages, they also have problems such as discoloration after detaching from the plant and being prone to drying and brittleness, which are difficult to store. Therefore, in view of the above disadvantages of leaves, providing a non-drying colored leaf is of great significance for the effective utilization and treatment of biological waste resources, and enables leaves to have a wider application prospect in many fields such as art decoration, smart home, flexible electronic devices and humidity indication. Summary of the Invention

[0003] The purpose of the present invention is to provide a long-acting moisturizing colored leaf and its preparation method and application. The colored leaf prepared by the present invention will not be damaged even after operations such as bending and folding, can restore its original shape after being folded and then released, has good toughness, and will not fade after being soaked in water for 48 hours.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method of a long-acting moisturizing colored leaf, comprising the following steps:

[0006] (1) Extract the pigment in natural plants using an organic solution to obtain a pigment solution;

[0007] (2) Mix the pigment solution obtained in step (1) with a hygroscopic salt to obtain a colored hygroscopic solution;

[0008] (3) Mix the colored hygroscopic solution obtained in step (2) with decolorized leaves, and then perform a vacuum pumping treatment to obtain a long-acting moisturizing colored leaf.

[0009] Preferably, the natural plant in step (1) contains any one or more of plants containing anthocyanin, chlorophyll, lutein and brazilin pigment.

[0010] Preferably, the organic solution in step (1) is anhydrous ethanol or an ethanol aqueous solution.

[0011] Preferably, the hygroscopic salts in the step (2) are metal halides.

[0012] Preferably, the hygroscopic salts in the step (2) are one or more of calcium chloride, lithium chloride, magnesium chloride, zinc chloride, sodium iodide, calcium bromide, zinc bromide, sodium iodide and lithium iodide.

[0013] Preferably, the mass concentration of the hygroscopic salts in the colored hygroscopic solution in the step (2) is ≥1%.

[0014] Preferably, the method for preparing the decolorized leaves in the step (3) is to immerse the natural leaves in the decolorizing solution, and then perform sealing and decolorizing treatments in sequence to obtain the decolorized leaves.

[0015] Preferably, the time of the vacuum treatment in the step (3) is ≥2 h, and the degree of vacuum of the vacuum treatment is ≤80 kPa.

[0016] The present invention provides long-lasting moisture-retaining colored leaves prepared by the preparation method described in the above technical solution.

[0017] The present invention provides the application of the long-lasting moisture-retaining colored leaves described in the above technical solution in artistic decoration, smart home, flexible electronic devices and humidity indication.

[0018] The present invention provides a method for preparing long-lasting moisture-retaining colored leaves, comprising the following steps: (1) extracting pigments in natural plants with an organic solution to obtain a pigment solution; (2) mixing the pigment solution obtained in the step (1) with hygroscopic salts to obtain a colored hygroscopic solution; (3) mixing the colored hygroscopic solution obtained in the step (2) with decolorized leaves, and then performing vacuum treatment to obtain long-lasting moisture-retaining colored leaves. After extracting the pigments in natural plants and mixing them with hygroscopic salts, and introducing them into the decolorized leaves by means of vacuum, since the pigments contain substances such as chlorophyll, lutein and brazilin which are insoluble in water, the color of the subsequently prepared colored leaves will not dissolve in water, making it have the advantage of not losing color when encountering water; at the same time, due to the introduction of hygroscopic salts, it can lock the moisture in the colored leaves, avoid the loss of moisture, and can absorb the moisture in the air, making the colored leaves have a long-lasting moisture-retaining effect, so that the colored leaves can be stored indoors for a long time and have good flexibility, comparable to that of fresh leaves, solving the problems of difficult storage such as color change and easy drying and brittleness after natural leaves are separated from plants; the raw materials used are natural plant leaves, and partial plant wastes can be used, the raw material sources are rich, the cost is low, and at the same time, no auxiliary additives are introduced during the preparation process, which is non-toxic and harmless and has a good environmental protection effect.

[0019] The colored leaves prepared by the preparation method provided by the present invention have the advantages of rich raw material sources, colors derived from natural pigments, no color fading when exposed to water, long-term storage indoors, good flexibility, no addition of auxiliary additives, non-toxic and harmless, etc., and have great application potential in many fields such as art decoration, smart home, flexible electronic devices, and humidity indication.

[0020] The results of the examples show that the colored leaves prepared by the preparation method provided by the present invention will not be damaged even after operations such as bending and folding, can restore their original shape after folding and releasing, have good toughness, and the colored leaves will not fade after being soaked in water for 48 hours. Description of the Drawings

[0021] Figure 1 It is a physical picture of the decolorized leaves obtained in step (1) of Example 1;

[0022] Figure 2 It is a physical picture of the colored leaves prepared in Example 2;

[0023] Figure 3 It is a comparison diagram of the original state, bent state, curled state, and folded state of the colored leaves prepared in Example 3;

[0024] Figure 4 It is a comparison diagram of the states of the colored leaves in Example 3 after folding and releasing;

[0025] Figure 5 It is a comparison diagram of the states of the fresh bodhi leaves in Comparative Example 1 after folding and releasing;

[0026] Figure 6 It is a comparison diagram of the states of the dried bodhi leaves in Comparative Example 2 after folding and releasing;

[0027] Figure 7 It is a physical picture of the colored leaves prepared in Example 2 and Example 3 placed in water;

[0028] Figure 8 It is a physical picture of the colored leaves prepared in Example 2 and Example 3 placed in water for 48 hours. Detailed Embodiments

[0029] The present invention provides a preparation method for long-acting moisturizing colored leaves, comprising the following steps:

[0030] (1) Extract the pigments in natural plants using an organic solution to obtain a pigment solution;

[0031] (2) Mix the pigment solution obtained in step (1) with hygroscopic salts to obtain a colored hygroscopic solution;

[0032] (3) Mix the colored moisture-absorbing solution obtained in step (2) with the decolorized leaves, and then perform vacuum pumping to obtain long-lasting moisture-retaining colored leaves.

[0033] The present invention uses an organic solution to extract pigments from natural plants to obtain a pigment solution.

[0034] In the present invention, the natural plant preferably includes any one or more of plants containing anthocyanin, chlorophyll, lutein, and brazilin, more preferably any one or more of leguminous plants, large tree plants, rutaceous plants, ulmaceae plants, salicaceae plants, and ebenaceae plants, and further preferably powder of Pterocarpus santalinus, powder of Dalbergia cearensis, powder of Pterocarpus macrocarpus, powder of Pterocarpus dalbergioides, powder of Pterocarpus pedatus, powder of Pterocarpus indicus, powder of Pterocarpus cambodianus, leaves of Ficus religiosa, leaves of Citrus reticulata, leaves of Ulmus pumila, or leaves of Salix babylonica. The present invention uses the above natural plants, which contain more pigments and are easier to extract. At the same time, chlorophyll, lutein, brazilin, etc. extracted are substances insoluble in water. Therefore, the color of the colored leaves prepared subsequently will not dissolve in water, making it have the advantage of not fading when exposed to water.

[0035] In the present invention, the organic solution is preferably anhydrous ethanol or an ethanol aqueous solution; the mass concentration of the ethanol aqueous solution is preferably ≥50%, more preferably 50-100%. As an embodiment of the present invention, the mass concentration of the ethanol aqueous solution can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. The present invention uses anhydrous ethanol or an ethanol aqueous solution to extract natural plants, which can improve the extraction efficiency.

[0036] The present invention has no special limitation on the dosage relationship between the natural plant and the organic solution, which is determined according to the common technical knowledge of those skilled in the art, as long as the organic solution can completely immerse the natural plant.

[0037] In the present invention, the extraction temperature is preferably room temperature. The present invention has no special limitation on the extraction time, which is determined according to the common technical knowledge of those skilled in the art, as long as the pigments in the natural plant can be extracted as much as possible.

[0038] After the extraction, the present invention preferably further includes evaporating the extracted product or first performing evaporation treatment and then mixing it with absolute ethanol. The present invention has no special limitation on the specific operation of the evaporation treatment, and the solvent in the product can be evaporated according to the required color concentration. In the present invention, the step of first performing evaporation treatment and then mixing with absolute ethanol preferably means completely evaporating the solvent in the product and then adding absolute ethanol according to the remaining pigment mass and the concentration of the required pigment solution. The present invention has no special limitation on the dosage of the absolute ethanol, which can be determined according to the concentration of the required pigment solution. Through the evaporation treatment, the content of the organic solution can be reduced, so that the concentration of the pigment solution becomes deeper, and the required color concentration can be obtained; by first performing evaporation treatment and then mixing with absolute ethanol, the concentration of the pigment solution can be controlled.

[0039] After obtaining the pigment solution, the present invention mixes the pigment solution with a hygroscopic salt to obtain a colored hygroscopic solution.

[0040] In the present invention, the hygroscopic salt is preferably a metal halide, more preferably one or more of calcium chloride, lithium chloride, magnesium chloride, zinc chloride, sodium iodide, calcium bromide, zinc bromide, sodium iodide and lithium iodide, and further preferably calcium chloride.

[0041] In the present invention, the mass concentration of the hygroscopic salt in the colored hygroscopic solution is preferably ≥1%, more preferably 1-50%. As an embodiment of the present invention, the mass concentration of the hygroscopic salt in the colored hygroscopic solution can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%. By controlling the dosage of the hygroscopic salt, the present invention can regulate its moisturizing effect, thereby further improving its long-term moisturizing ability.

[0042] The present invention has no special limitation on the specific operation of mixing the pigment solution with the hygroscopic salt, which can be determined according to the common technical knowledge of those skilled in the art and can make them mix evenly.

[0043] After obtaining the colored hygroscopic solution, the present invention mixes the colored hygroscopic solution with decolorized leaves and then performs vacuum treatment to obtain long-term moisturizing colored leaves.

[0044] In the present invention, the preparation method of the decolorized leaves is preferably to immerse natural leaves in a decolorizing solution and then perform sealing and decolorizing treatments in sequence to obtain decolorized leaves.

[0045] In the present invention, the natural leaves preferably include the leaves of broad-leaved plants, more preferably the leaves of Ficus religiosa, willow, elm, peach or maple. By using the leaves of broad-leaved plants, the present invention has the advantages of good aesthetics and long moisturizing time.

[0046] The present invention has no special limitation on the specific operation of the enclosure, and it is only necessary to enclose the container containing natural leaves and the decolorizing solution.

[0047] In the present invention, the decolorizing solution is preferably a mixed solution of sodium chlorite, glacial acetic acid and water or a mixed solution of sodium hypochlorite, glacial acetic acid and water, and more preferably a mixed solution of sodium chlorite, glacial acetic acid and water. In the present invention, in the mixed solution of sodium chlorite, glacial acetic acid and water, the mass concentration of sodium chlorite is preferably 9-10%, more preferably 9.88%; the mass concentration of glacial acetic acid in the mixed solution of sodium chlorite, glacial acetic acid and water is preferably 0.15-0.3%, more preferably 0.21%; in the mixed solution of sodium hypochlorite, glacial acetic acid and water, the mass concentration of sodium hypochlorite is preferably 9-10%, more preferably 9.88%; the mass concentration of glacial acetic acid in the mixed solution of sodium hypochlorite, glacial acetic acid and water is preferably 0.15-0.3%, more preferably 0.21%. Sodium chlorite / sodium hypochlorite and glacial acetic acid in the decolorizing solution provided by the present invention are the effective components of the decolorizing solution, which can effectively remove the color of the leaves; by controlling the concentrations of sodium chlorite / sodium hypochlorite and glacial acetic acid in the decolorizing solution, a better decolorizing effect can be achieved.

[0048] The present invention preferably adds the effective components of the decolorizing solution during the decolorization treatment. In the present invention, the effective components of the decolorizing solution are preferably sodium chlorite / sodium hypochlorite and glacial acetic acid. In the present invention, the number of times of adding the effective components of the decolorizing solution is preferably 1-10 times. As an embodiment of the present invention, the number of times of adding the effective components of the decolorizing solution can be 1 time, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times or 10 times. In the present invention, the addition of the effective components of the decolorizing solution is preferably carried out under stirring conditions. The present invention has no special limitation on the addition amount of the effective components of the decolorizing solution, and it is only necessary to make the concentration of the effective components in the decolorizing solution after addition the same as that in the decolorizing solution at the beginning. The present invention has no special limitation on the stirring rate and time, and it is only necessary to make it evenly mixed. By adding the effective components of the decolorizing solution multiple times, the present invention can avoid the problem of incomplete decolorizing effect caused by too low concentration.

[0049] In the present invention, the temperature of the decolorization treatment is preferably 50-90°C; the time of the decolorization treatment is preferably 0.5-6 h. As an embodiment of the present invention, the temperature of the decolorization treatment can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C; the time of the decolorization treatment can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h. By controlling the parameters of the decolorization treatment, the present invention can further improve the decolorizing effect.

[0050] Preferably after the decolorization treatment, the product of the decolorization treatment is preferably washed in the present invention. The present invention has no special limitation on the specific operation of the washing, and it is only necessary to wash until the surface is neutral. By washing in the present invention, residual chemical components can be removed to avoid their influence on the color of the subsequent leaves.

[0051] The present invention has no special limitation on the dosages and mixing methods of the colored moisture-absorbing solution and the decolorized leaves, and it is only necessary to completely immerse the decolorized leaves in the colored moisture-absorbing solution.

[0052] In the present invention, the time of the vacuum pumping treatment is preferably ≥ 2 h, more preferably 2 - 12 h; the degree of vacuum of the vacuum pumping treatment is preferably ≤ 80 kPa. As an embodiment of the present invention, the time of the vacuum pumping treatment can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 12 h. The present invention has no special limitation on the specific operation of the vacuum pumping treatment, and it is only necessary to enable the pigments and hygroscopic salts in the colored moisture-absorbing solution to enter the decolorized leaves. By the vacuum pumping treatment in the present invention, the pigments and hygroscopic salts in the colored moisture-absorbing solution can enter the decolorized leaves, so that the leaves present the required color, and at the same time, they do not fade when encountering water and can be stored indoors for a long time.

[0053] After the vacuum pumping treatment is completed, the present invention preferably further includes flattening the product of the vacuum pumping treatment. In the present invention, the time of the flattening is preferably ≥ 10 min, more preferably 10 - 120 min. The present invention has no special limitation on the types and masses of the heavy objects used during the flattening, and heavy objects well-known to those skilled in the art can be used as long as the leaves can be flattened. As an embodiment of the present invention, the time of the flattening can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min; during the flattening, the mass required for every 100 cm 2 of the leaves is preferably ≥ 1 kg. By flattening in the present invention, the appearance of the colored leaves can be made flat and the aesthetics is good.

[0054] After extracting the pigments from natural plants and mixing them with hygroscopic salts, they are introduced into the decolorized leaves by means of vacuum pumping. Since the chlorophyll, lutein, brazilin and other substances contained in the pigments are insoluble in water, the colors of the subsequently prepared colored leaves will not dissolve in water, giving them the advantage of not fading when exposed to water. At the same time, due to the introduction of hygroscopic salts, they can lock the moisture in the colored leaves, avoid water loss, and can also absorb moisture in the air, enabling the colored leaves to have a long-term moisturizing effect. As a result, the colored leaves can be stored indoors for a long time and have good flexibility, comparable to that of fresh leaves, solving the problems of difficult storage such as color change and easy drying and brittleness after natural leaves are separated from plants. The raw materials used are natural plant leaves, and some plant wastes can also be used. The raw material sources are rich and the cost is low. At the same time, no auxiliary additives are introduced during the preparation process, which is non-toxic and harmless and has a good environmental protection effect.

[0055] The colored leaves prepared by using the preparation method provided by the present invention have the advantages of rich raw material sources, colors derived from natural pigments, not fading when exposed to water, being able to be stored indoors for a long time, having good flexibility, no auxiliary additives added, and being non-toxic and harmless, and have great application potential in many fields such as art decoration, smart home, flexible electronic devices and humidity indication.

[0056] The present invention also provides a long-term moisturizing colored leaf prepared by the preparation method described in the above technical solution.

[0057] While presenting the colors of nature, the long-term moisturizing colored leaf provided by the present invention can also absorb moisture for a long time, never dry out, and maintain the same flexibility as fresh leaves.

[0058] The present invention also provides the application of the long-term moisturizing colored leaf described in the above technical solution in art decoration, smart home, flexible electronic devices and humidity indication.

[0059] The long-term moisturizing colored leaf provided by the present invention can absorb moisture in the air, contain water inside, have electrical conductivity, and have a certain flexibility, and can be used as a flexible conductive material; using the electrical signal generated by rubbing the leaves, it can be used in a smart home system; by monitoring the change of the electrical conductivity of the leaves at different humidities, the indoor air humidity can be reflected to achieve humidity indication. The present invention has no special limitation on the specific operation of the application, and the application methods well-known to those skilled in the art can be adopted.

[0060] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in 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 in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] Example 1

[0062] A preparation method of long-acting moisturizing colored leaves comprises the following steps:

[0063] (1) Immerse natural bodhi leaves in a decolorizing solution, then successively perform sealing and decolorizing treatments. During the decolorizing treatment, the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, are added twice under stirring conditions, and the interval between each addition is 1 h. The natural bodhi leaves turn white, and finally the leaves are taken out and washed to neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water, and the mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature of the decolorizing treatment is 75°C, and the total time of the decolorizing treatment is 3 h;

[0064] (2) Immerse 50 g of red sandalwood powder in absolute ethanol, let it stand at room temperature. When the solution turns dark, filter out the red sandalwood powder, and after evaporation treatment, obtain a pigment solution;

[0065] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0066] (4) Immerse the decolorized leaves obtained in step (1) in the colored hygroscopic solution obtained in step (3), then perform vacuum pumping treatment, and finally flatten them with a heavy object to obtain long-acting moisturizing colored leaves; the time of the vacuum pumping treatment is 6 h, and the vacuum degree of the vacuum pumping treatment is 80 kPa; the flattening time is 120 min. When flattening, the required mass for every 100 cm 2 of leaves is 1 kg.

[0067] Example 2

[0068] A preparation method of long-acting moisturizing colored leaves comprises the following steps:

[0069] (1) Immerse natural bodhi leaves in the decolorizing solution, then successively carry out sealing and decolorizing treatments. During the decolorizing treatment process, add the active ingredients of the decolorizing solution, sodium hypochlorite and glacial acetic acid, twice under stirring conditions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves. The decolorizing solution is a mixed solution of sodium hypochlorite, glacial acetic acid and water. The mass concentration of sodium hypochlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%. The temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0070] (2) Immerse 50 g of rosewood powder in absolute ethanol, and let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution;

[0071] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution. The hygroscopic salts are calcium chloride. The mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0072] (4) Immerse the decolorized leaves obtained in step (1) in the colored hygroscopic solution obtained in step (3), then carry out vacuum pumping treatment, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves. The time of the vacuum pumping treatment is 6 h, and the vacuum degree of the vacuum pumping treatment is 80 kPa. The time of flattening is 120 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0073] Example 3

[0074] A preparation method of long-lasting moisturizing colored leaves comprises the following steps:

[0075] (1) Immerse natural bodhi leaves in the decolorizing solution, then successively carry out sealing and decolorizing treatments. During the decolorizing treatment process, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves. The decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%. The temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0076] (2) Immerse 50 g of willow leaves in absolute ethanol, and let it stand at room temperature. When the solution turns dark, filter out the willow leaves, and after evaporation treatment, obtain a pigment solution;

[0077] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0078] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum pumping, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum pumping is 6 h, and the vacuum degree for the vacuum pumping is 80 kPa; the time for flattening is 120 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0079] Example 4

[0080] A method for preparing long-lasting moisturizing colored leaves comprises the following steps:

[0081] (1) Immerse natural bodhi leaves into a decolorizing solution, then perform sealing and decolorizing treatments in sequence. During the decolorizing treatment process, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, and the interval between each addition is 1 h. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature for the decolorizing treatment is 75 °C, and the total time for the decolorizing treatment is 3 h;

[0082] (2) Immerse 50 g of rosewood powder into an ethanol aqueous solution with a mass concentration of 50%, and let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution;

[0083] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0084] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum pumping, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum pumping is 6 h, and the vacuum degree for the vacuum pumping is 80 kPa; the time for flattening is 120 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0085] Example 5

[0086] A method for preparing long-lasting moisturizing colored leaves comprises the following steps:

[0087] (1) Immerse the natural bodhi leaves in the decolorizing solution, and then perform sealing and decolorizing treatments in sequence. During the decolorizing treatment, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, under stirring conditions in two portions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves. The decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid, and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%. The temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h.

[0088] (2) Immerse 50 g of rosewood powder in an aqueous ethanol solution with a mass concentration of 75%, and let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution.

[0089] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution. The hygroscopic salts are calcium chloride. The mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%.

[0090] (4) Immerse the decolorized leaves obtained in step (1) in the colored hygroscopic solution obtained in step (3), then perform vacuum pumping treatment, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves. The time of the vacuum pumping treatment is 6 h, and the vacuum degree of the vacuum pumping treatment is 80 kPa. The time of flattening is 120 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0091] Example 6

[0092] A preparation method of long-lasting moisturizing colored leaves comprises the following steps:

[0093] (1) Immerse the natural bodhi leaves in the decolorizing solution, and then perform sealing and decolorizing treatments in sequence. During the decolorizing treatment, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, under stirring conditions in two portions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves. The decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid, and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%. The temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h.

[0094] (2) Immerse 50 g of rosewood powder in absolute ethanol, and let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution.

[0095] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 10%;

[0096] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum pumping, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum pumping is 6 h, and the degree of vacuum for the vacuum pumping is 80 kPa; the time for flattening is 120 min. When flattening, for every 100 cm 2 of leaves, the required mass is 1 kg.

[0097] Example 7

[0098] A method for preparing long-lasting moisturizing colored leaves, comprising the following steps:

[0099] (1) Immerse natural bodhi leaves into a decolorizing solution, then perform sealing and decolorizing treatments in sequence. During the decolorizing treatment, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, and the interval between each addition is 1 h. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0100] (2) Immerse 50 g of red sandalwood powder into absolute ethanol, let it stand at room temperature. When the solution turns dark, filter out the red sandalwood powder, and after evaporation treatment, obtain a pigment solution;

[0101] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 5%;

[0102] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum pumping, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum pumping is 6 h, and the degree of vacuum for the vacuum pumping is 80 kPa; the time for flattening is 120 min. When flattening, for every 100 cm 2 of leaves, the required mass is 1 kg.

[0103] Example 8

[0104] A method for preparing long-lasting moisturizing colored leaves, comprising the following steps:

[0105] (1) Immerse natural bodhi leaves in a decolorizing solution, then successively carry out sealing and decolorizing treatments. During the decolorizing treatment process, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water, and the mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0106] (2) Immerse 50 g of rosewood powder in absolute ethanol, let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution;

[0107] (3) Mix the pigment solution obtained in step (2) with a hygroscopic salt to obtain a colored hygroscopic solution; the hygroscopic salt is calcium chloride; the mass concentration of the hygroscopic salt in the colored hygroscopic solution is 20%;

[0108] (4) Immerse the decolorized leaves obtained in step (1) in the colored hygroscopic solution obtained in step (3), then carry out vacuum pumping treatment, and finally flatten with a heavy object to obtain long-lasting moisturizing colored leaves; the time of the vacuum pumping treatment is 2 h, and the vacuum degree of the vacuum pumping treatment is 80 kPa; the flattening time is 120 min. When flattening, the required mass for every 100 cm 2 of leaves is 1 kg.

[0109] Example 9

[0110] A preparation method of long-lasting moisturizing colored leaves, which is the following steps:

[0111] (1) Immerse natural bodhi leaves in a decolorizing solution, then successively carry out sealing and decolorizing treatments. During the decolorizing treatment process, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, with an interval of 1 h between each addition. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water, and the mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0112] (2) Immerse 50 g of rosewood powder in absolute ethanol, let it stand at room temperature. When the solution turns dark, filter out the rosewood powder, and after evaporation treatment, obtain a pigment solution;

[0113] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0114] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum treatment, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum treatment is 12 h, and the vacuum degree for the vacuum treatment is 80 kPa; the flattening time is 120 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0115] Example 10

[0116] A preparation method of long-lasting moisturizing colored leaves comprises the following steps:

[0117] (1) Immerse natural bodhi leaves into a decolorizing solution, then perform sealing and decolorizing treatments in sequence. During the decolorizing treatment, add the active ingredients of the decolorizing solution, sodium chlorite and glacial acetic acid, twice under stirring conditions, and the interval between each addition is 1 h. The natural bodhi leaves turn white. Finally, take out the leaves and wash them until neutral to obtain decolorized leaves; the decolorizing solution is a mixed solution of sodium chlorite, glacial acetic acid and water. The mass concentration of sodium chlorite in the mixed solution is 9.88%, and the mass concentration of glacial acetic acid is 0.21%; the temperature of the decolorizing treatment is 75 °C, and the total time of the decolorizing treatment is 3 h;

[0118] (2) Immerse 50 g of red sandalwood powder into absolute ethanol, let it stand at room temperature. When the solution turns dark, filter out the red sandalwood powder, and after evaporation treatment, obtain a pigment solution;

[0119] (3) Mix the pigment solution obtained in step (2) with hygroscopic salts to obtain a colored hygroscopic solution; the hygroscopic salts are calcium chloride; the mass concentration of the hygroscopic salts in the colored hygroscopic solution is 20%;

[0120] (4) Immerse the decolorized leaves obtained in step (1) into the colored hygroscopic solution obtained in step (3), then perform vacuum treatment, and finally flatten them with heavy objects to obtain long-lasting moisturizing colored leaves; the time for the vacuum treatment is 6 h, and the vacuum degree for the vacuum treatment is 80 kPa; the flattening time is 10 min. When flattening, the mass required for every 100 cm 2 of leaves is 1 kg.

[0121] Comparative Example 1

[0122] Fresh bodhi leaves.

[0123] Comparative Example 2

[0124] Dried bodhi leaves.

[0125] Figure 1 It is a physical picture of the decolorized leaves obtained in step (1) of Example 1. It can be seen from Figure 1 that after the decolorization treatment, the bodhi leaves are basically in a colorless state.

[0126] Figure 2 It is a physical picture of the colored leaves prepared in Example 2. It can be seen from Figure 2 that after the bodhi leaves are subjected to decolorization treatment and subsequent vacuum pumping treatment, the color changes from the original green to red, having good ornamental value.

[0127] Figure 3 It is a comparison diagram of the original state, bent state, curled state, and folded state of the colored leaves prepared in Example 3. It can be seen from Figure 3 that the colored leaves obtained by the preparation method of the present invention have good toughness and will not be damaged even after operations such as bending and folding.

[0128] Figure 4 It is a comparison diagram of the state of the colored leaves of Example 3 after folding and then releasing, Figure 5 It is a comparison diagram of the state of the fresh bodhi leaves of Comparative Example 1 after folding and then releasing, Figure 6 It is a comparison diagram of the state of the dried bodhi leaves of Comparative Example 2 after folding and then releasing. It can be seen from Figures 4 to 6 that the fresh bodhi leaves and the dried bodhi leaves cannot restore their original shapes after folding and then releasing, while the colored leaves prepared by the present invention can restore their original shapes after folding and then releasing, indicating that the colored leaves obtained by the preparation method of the present invention have good toughness.

[0129] Figure 7 It is a physical picture of the colored leaves prepared in Example 2 and Example 3 placed in water, Figure 8 It is a physical picture of the colored leaves prepared in Example 2 and Example 3 placed in water for 48 hours. It can be seen from Figure 7 and Figure 8 that the colored leaves prepared by the preparation method provided by the present invention will not fade after long-term contact with water.

[0130] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing long-lasting moisturizing colored leaves, comprising the following steps: (1) extracting pigments from natural plants using an organic solvent to obtain a pigment solution; (2) mixing the pigment solution obtained in step (1) with a hygroscopic salt to obtain a colored hygroscopic solution; (3) The colored hygroscopic solution obtained in step (2) is mixed with the decolorized leaves, and then vacuum treated to obtain colored leaves with long-lasting moisturizing properties.

2. The preparation method according to claim 1, characterized in that: The natural plants in step (1) contain any one or more of anthocyanins, chlorophyll, lutein and annatto pigments.

3. The preparation method according to claim 1, characterized in that: The organic solution in step (1) is anhydrous ethanol or ethanol aqueous solution.

4. The preparation method according to claim 1, characterized in that: The hygroscopic salt in step (2) is a metal halide.

5. The preparation method according to claim 1 or 4, characterized in that: The hygroscopic salt in step (2) is one or more of calcium chloride, lithium chloride, magnesium chloride, zinc chloride, sodium iodide, calcium bromide, zinc bromide, sodium iodide and lithium iodide.

6. The preparation method according to claim 1, characterized in that: The mass concentration of the hygroscopic salts in the colored hygroscopic solution in step (2) is ≥ 1%.

7. The preparation method according to claim 1, characterized in that: The method for preparing the decolorized leaves in step (3) is to immerse the natural leaves in a decolorizing solution, and then sequentially perform sealing and decolorizing treatments to obtain decolorized leaves.

8. The preparation method according to claim 1, characterized in that: The time of the vacuum treatment in step (3) is ≥2h, and the vacuum degree of the vacuum treatment is ≤80kPa.

9. Long-lasting and moisturizing colored leaves prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the long-lasting moisturizing colored leaves according to claim 9 in art decoration, smart home, flexible electronic devices and humidity indication.

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