Black tea or coffee extract reinforced HPC photon gel and preparation and application thereof
By introducing black tea or coffee extracts as background colors into HPC photonic gels, the problems of biotoxicity and limited functionality of traditional background materials are solved, visual recognition is improved, and antioxidant activity and unique flavor are added, achieving a combination of functionality and visual effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-06
- Publication Date
- 2026-04-14
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of functional materials technology, specifically to a black tea or coffee extract-reinforced HPC (hydroxypropyl cellulose) photonic gel, its preparation method, and its application as a 3D printing material. Background Technology
[0002] Structural color is a color produced by the interaction of light with the ordered structure formed at the micro or nanoscale of a material. It boasts advantages such as high color saturation, resistance to fading, and environmental friendliness, showing broad application prospects in optical displays, anti-counterfeiting packaging, smart sensing, and food materials. Hydroxypropyl cellulose (HPC) is an abundant and easily degradable polymer material that can form a chiral nematic liquid crystal phase and produce structural color in high-concentration aqueous solutions (60–70 wt%). However, to clearly display its structural color, a background color is often needed to enhance its contrast with the environment, thereby improving visual recognition. Furthermore, HPC gel exhibits significant shear-thinning behavior and rapid structural recovery ability, demonstrating excellent 3D printing adaptability. Through 3D printing technology, HPC can be used to construct photonic objects with rich geometric shapes and colors, and dynamic tunability.
[0003] In the application of photonic gels, a background material with high absorbency is usually introduced to enhance the contrast of the structural color of HPC photonic gels. However, existing background color materials suffer from problems such as biotoxicity, limited functionality, and lack of responsiveness, which seriously restricts the expansion of HPC photonic gel applications. Taking patent CN117050250A as an example, it uses carbon black as the gel background color, which can improve the visual recognition of the structural color, but carbon black itself has limited functionality and lacks bioactivity and responsiveness, which is not conducive to the development of multifunctional materials. Another patent CN116607227A uses carbon nanotubes as the background color, using their excellent conductivity to introduce electronic sensing functions into the material, but studies have shown that carbon nanotubes may induce lung inflammation, posing a potential biosafety risk.
[0004] Black tea pigment is a natural pigment found in black tea. It is formed through the oxidative polymerization of polyphenols during tea fermentation and mainly includes theaflavins, thearubigins, and some theabrownins. Black tea pigment has advantages such as bright color, good stability, non-toxicity, and non-allergenicity, and also possesses antioxidant and antibacterial functions. Coffee pigment is a natural pigment found in coffee. It is mainly composed of chlorogenic acid oxidation products, melanoidins, and polyphenols such as tannins, formed during the roasting of coffee beans through Maillard and caramelization reactions. Coffee pigment is brown in color and has advantages such as being environmentally friendly, highly biocompatible, and widely available. In addition, the unique aromas of black tea and coffee extracts can also impart unique flavors to materials. Therefore, using coffee or black tea extracts as the background color for HPC photonic gels is expected to improve the visual contrast of HPC photonic gels and may also provide antioxidant and other bioactive effects through the introduction of pigment molecules, as well as impart a unique flavor to HPC photonic gels. Summary of the Invention
[0005] To overcome the limitations and shortcomings of existing technologies, the technical problem to be solved by this invention is to provide a HPC photonic gel reinforced with black tea or coffee extract, its preparation method, and its application as a 3D printing material. By introducing black tea or coffee extract as a background color, the visual recognition of the structural color of the HPC photonic gel is improved while endowing the material with functional properties. On this basis, 3D printing technology is further used to prepare photonic gel materials with geometric structure, black tea or coffee aroma, rich colors, and functionality.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] In a first aspect, the present invention provides a method for preparing HPC photonic gel enhanced with black tea or coffee extract, comprising the following steps:
[0008] Step 1: Mix the black tea or coffee water extract with HPC at a mass ratio of 32-38%: 68-62% to obtain a mixture; the black tea or coffee water extract is obtained by the following method: mix black tea or coffee grounds with deionized water, heat to extract, and filter after extraction to obtain the black tea or coffee water extract;
[0009] Step 2: The mixture obtained in step (1) is placed in a water bath at 25-35℃ for 1.5-2 hours. The mixture is stirred thoroughly to ensure that the components are evenly distributed. Then, the air bubbles are removed by centrifugation at room temperature. The centrifuged gel is stored at 4-25℃ until the structural color is uniform, thus obtaining the HPC photonic gel reinforced with tea and coffee extracts.
[0010] The black tea or coffee water extract of this invention is obtained by the following method: mixing black tea or coffee grounds with deionized water, heating and extracting, and filtering after extraction to obtain the black tea or coffee water extract. In some embodiments, the mass ratio of black tea to deionized water is 10-40:1000, preferably 25:1000; the extraction conditions are: heating to 80-100℃ and extracting for 10-30 minutes, preferably heating to 100℃ and extracting for 20 minutes. In some embodiments, the mass ratio of coffee grounds to deionized water is 100-200:1000, preferably 150:1000; the extraction conditions are: heating to 70-90℃ and extracting under ultrasonic assistance for 60-100 minutes, preferably heating to 80℃ and extracting for 80 minutes at an ultrasonic power of 250 W.
[0011] Preferably, in step 2, the water bath temperature is 30-35℃, more preferably 33℃; and the water bath time is 1.5-2 hours, more preferably 2 hours.
[0012] Preferably, in step 2, the stirring time is 50-70 minutes, more preferably 60 minutes.
[0013] Preferably, in step 2, the centrifugation conditions are 10,000-12,000 rpm for 25-45 minutes, and more preferably, 12,000 rpm for 45 minutes.
[0014] Preferably, in step 2, the storage condition is 4°C.
[0015] In a second aspect, the present invention provides an HPC photonic gel prepared according to the preparation method described in the first aspect.
[0016] Thirdly, the present invention provides the application of the HPC photonic gel described in the second aspect as a 3D printing material.
[0017] In some implementations, the application specifically includes the following steps:
[0018] The HPC photonic gel described in the second aspect is filled into a 3D printing container, the temperature is raised to 70-90°C, and then the printing operation is performed.
[0019] Preferably, the printing temperature is 80°C.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] (1) The preparation method of HPC photonic gel enhanced by black tea or coffee extract described in this invention is simple to operate. It directly uses black tea or coffee water extract as the dissolving medium for HPC, without the need to further extract the pigments in black tea and coffee, thus shortening the preparation process. In addition, the material is safe, non-toxic, and environmentally friendly.
[0022] (2) In the HPC photonic gel system described in this invention, black tea and coffee water extracts are innovatively introduced as background colors to replace traditional black base materials, which can improve the visual recognition of HPC structural colors. At the same time, since black tea and coffee extracts also have physiological functional properties that are beneficial to the human body, such as antioxidant and other biological activities, this invention can also endow HPC photonic gel materials with antioxidant activity and other functional properties. In addition, thanks to the natural aroma substances contained in the extracts, the gel material also has the characteristic aroma of black tea or coffee.
[0023] (3) This invention uses HPC photonic gel as a 3D printing material. Even after high-temperature printing, it retains a distinct structural color, enabling the preparation of HPC photonic materials with geometric structures, characteristic aromas, vibrant colors, and functional properties, thus possessing broad application potential in numerous fields. In summary, the plant extract-enhanced HPC photonic gel constructed in this invention provides a new strategy for developing green and efficient photonic functional materials. Attached Figure Description
[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0025] Figure 1 A typical preparation flow diagram of HPC photonic gels reinforced with black tea and coffee extracts.
[0026] Figure 2 : Physical images of the HPC photonic gels prepared in Comparative Examples 1-2 and Examples 1-2.
[0027] Figure 3 : Physical images of the HPC photonic gels prepared in Examples 1-2 and 3-4.
[0028] Figure 4 : Physical images of the 3D printed HPC photonic materials prepared in Comparative Examples 3 and 5. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.
[0030] The material involved in this invention is HPC with a molecular weight of 100,000, purchased from China National Pharmaceutical Group Corporation.
[0031] The following is the specific implementation process.
[0032] Comparative Example 1:
[0033] Pure water (3.2 g, 32 wt%) was mixed with HPC (6.8 g, 68 wt%). The mixture was incubated in a water bath at 33°C for 2 hours. The mixture was then stirred for 60 minutes using a cantilever electric stirrer. After stirring, the mixture was centrifuged at 12,000 rpm for 45 minutes to remove air bubbles. The well-mixed gel was then stored in a refrigerator at 4°C until the structural color became uniform, resulting in a blue HPC photonic gel with no background color and a water content of 32%.
[0034] Comparative Example 2:
[0035] Pure water (3.8 g, 38 wt%) was mixed with HPC (6.2 g, 62 wt%). The mixture was incubated in a water bath at 33°C for 2 hours. The mixture was then stirred for 60 minutes using a cantilever electric stirrer. After stirring, the mixture was centrifuged at 12,000 rpm for 45 minutes to remove air bubbles. The well-mixed gel was then stored in a refrigerator at 4°C until the structural color became uniform, resulting in an orange HPC photonic gel with no background color and a water content of 38%.
[0036] Example 1:
[0037] Step 1: Weigh 25 g of black tea and add it to 1000 mL of deionized water (extraction material to liquid ratio is 1:40). Boil at 100℃ for 20 min. After filtering, remove the black tea residue to obtain a black tea pigment solution.
[0038] Step 2: Mix the black tea extract (3.2 g, 32 wt%) with HPC (6.8 g, 68 wt%) in a 33°C water bath for 2 hours. Then, stir the mixture with a cantilever electric stirrer for 60 min. After stirring, centrifuge at 12000 rpm for 45 min to remove air bubbles. Place the well-mixed gel in a 4°C refrigerator until the structural color is uniform, and obtain a blue HPC photonic gel reinforced with black tea extract and a water content of 32%.
[0039] Example 2:
[0040] Step 1: Weigh 25 g of black tea and add it to 1000 mL of deionized water (extraction material to liquid ratio is 1:40). Boil at 100℃ for 20 min. After filtering, remove the black tea residue to obtain a black tea pigment solution.
[0041] Step 2: Mix the black tea extract (3.8 g, 38 wt%) with HPC (6.2 g, 62 wt%) in a 33°C water bath for 2 hours. Then, stir the mixture with a cantilever electric stirrer for 60 min. After stirring, centrifuge at 12000 rpm for 45 min to remove air bubbles. Store the well-mixed gel in a 4°C refrigerator until the structural color is uniform, to obtain an orange HPC photonic gel reinforced with black tea extract and containing 38% water.
[0042] Example 3:
[0043] Step 1: Weigh 150g of coffee grounds and add them to 1000mL of deionized water. Extract the coffee grounds by ultrasonication at 80℃ and 250w for 80min. After filtration, remove the coffee grounds to obtain a coffee pigment solution.
[0044] Step 2: The coffee extract (3.2 g, 32 wt%) and HPC (6.8 g, 68 wt%) were mixed in a water bath at 33°C for 2 hours. Then, the mixture was stirred for 60 min using a cantilever electric stirrer. After stirring, the mixture was centrifuged at 12000 rpm for 45 min to remove air bubbles. The well-mixed gel was stored in a refrigerator at 4°C until the structural color was uniform, resulting in a blue HPC photonic gel reinforced with coffee extract and containing 32% water.
[0045] Example 4:
[0046] Step 1: Weigh 150g of coffee grounds and add them to 1000mL of deionized water. Extract the coffee grounds by ultrasonication at 80℃ and 250w for 80min. After filtration, remove the coffee grounds to obtain a coffee pigment solution.
[0047] Step 2: The coffee extract (3.8 g, 38 wt%) and HPC (6.2 g, 62 wt%) were mixed in a water bath at 33°C for 2 hours. Then, the mixture was stirred for 60 min using a cantilever electric stirrer. After stirring, the mixture was centrifuged at 12000 rpm for 45 min to remove air bubbles. The well-mixed gel was stored in a refrigerator at 4°C until the structural color became uniform, resulting in an orange HPC photonic gel reinforced with coffee extract and containing 38% water.
[0048] Comparative Example 3:
[0049] Step 1: The HPC photonic gel prepared in Comparative Example 2 was preheated to 33°C and equilibrated for 2 hours. Then, the HPC photonic gel was filled into the hopper. The filled hopper was then placed in an environment of 33°C for equilibration for 24 hours to make the gel structure color uniform.
[0050] Step 2: Use a mechanical screw to push the gel filled in Step 1 out of the nozzle. Once a continuous stream of gel is being extruded from the nozzle, begin printing. The printer parameters are set as follows: nozzle diameter: 0.84mm, fill density: 100%, print speed: 3.75mm / s.
[0051] Step 3: Place the printed product at room temperature for 24 minutes to obtain HPC photonic gel material with geometric structure and structural color without background color.
[0052] Example 5:
[0053] Step 1: The HPC photonic gel prepared in Example 4 was preheated to 33°C and equilibrated for 2 hours. Then, the HPC photonic gel was filled into the hopper. The filled hopper was then placed in an environment of 33°C for equilibration for 24 hours to make the gel structure color uniform.
[0054] Step 2: Use a mechanical screw to push the gel filled in Step 1 out of the nozzle. Once a continuous stream of gel is being extruded from the nozzle, begin printing. The printer parameters are set as follows: nozzle diameter: 0.84mm, fill density: 100%, print speed: 3.75mm / s.
[0055] Step 3: Place the printed product at room temperature for 24 minutes to obtain HPC photonic gel material with geometric structure and structural color reinforced by coffee extract.
[0056] Experimental results
[0057] The photonic gels prepared in Examples 1-2 and 1-4 were compared, such as... Figure 2 As shown in Figure 3, the structural color of the HPC photogel without added background color lacks visual recognition due to the absence of light absorption by the background color material. Although the structural color is not affected by the background color, it can still be seen that the HPC photogel has formed a structural color. However, the structural color of the photogel should have a very obvious difference between different water contents. Figure 2 In the three photonic gels without background color, there was no significant difference in structural colors among the different structures. However, by using black tea or coffee extracts as the dispersion medium for HPC, the structural colors of the HPC photonic gels exhibited clear visual recognition due to the inherent color of the extracts themselves.
[0058] Using the photonic gels prepared in Comparative Examples 2 and 4 as raw materials for 3D printing, HPC photonic gel materials with geometric structural colors and structural colors were obtained, such as... Figure 4As shown, coffee extract as a dispersion medium for HPC photonic gel did not affect the 3D printing performance of HPC photonic gel. HPC photonic gel can be 3D printed to form HPC photonic materials with different geometries. Although printed at a high temperature of 80°C, the HPC photonic materials can still exhibit obvious structural colors after equilibration at room temperature for 24 hours.
[0059] In summary, the HPC photonic gel enhanced with black tea or coffee extract developed in this invention fully leverages the inherent color advantages of black tea and coffee extracts, directly using them as a dispersion medium for HPC. This improves the visual recognition of the HPC photonic gel while also endowing it with antioxidant and other bioactive properties. Furthermore, using the HPC photonic gel as a raw material for 3D printing can produce HPC photonic materials with distinct structural colors and geometric structures, and possessing the characteristic aroma of coffee or black tea, making it widely applicable in numerous fields.
Claims
1. A method for preparing an HPC photonic gel reinforced with black tea or coffee extract, characterized in that: The preparation method includes the following steps: Step 1: Mix the black tea or coffee water extract with HPC at a mass ratio of 32-38%: 68-62% to obtain a mixture; the black tea or coffee water extract is obtained by the following method: mix black tea or coffee grounds with deionized water, heat to extract, and filter after extraction to obtain the black tea or coffee water extract; Step 2: The mixture obtained in step (1) is placed in a water bath at 25-35℃ for 1.5-2 hours. The mixture is stirred thoroughly to ensure that the components are evenly distributed. Then, the air bubbles are removed by centrifugation at room temperature. The centrifuged gel is stored at 4-25℃ until the structural color is uniform, thus obtaining HPC photonic gel reinforced with black tea or coffee extract.
2. The preparation method according to claim 1, characterized in that: In step 1, during the preparation of the black tea water extract, the mass ratio of black tea to deionized water is 10-40:1000, and the extraction conditions are: heating to 80-100℃ and extraction for 10-30 minutes.
3. The preparation method according to claim 1, characterized in that: In step 1, during the preparation of the coffee water extract, the mass ratio of coffee grounds to deionized water is 100-200:10000; the extraction conditions are: heating to 70-90℃ and extraction under ultrasonic assistance for 60-100 minutes.
4. The preparation method according to any one of claims 1-3, characterized in that: In step 2, the water bath temperature is 30-35℃; the water bath time is 1.5-2 hours.
5. The preparation method according to claim 4, characterized in that: In step 2, the water bath temperature is 33℃; the water bath time is 2 hours.
6. The preparation method according to any one of claims 1-3, characterized in that: In step 2, the stirring time is 50-70 minutes.
7. The preparation method according to any one of claims 1-3, characterized in that: In step 2, the storage temperature is 4℃.
8. An HPC photonic gel reinforced with black tea or coffee extract, prepared by any one of claims 1-7.
9. The application of the HPC photonic gel reinforced with black tea or coffee extract as described in claim 8 as a 3D printing material.
10. The application as described in claim 9, characterized in that: The application specifically includes the following steps: The HPC photonic gel, reinforced with the black tea or coffee extract, is filled into a 3D printing container, the temperature is raised to 70-90°C, and then the printing operation is performed.