Pearlescent material and method with pearlescent effect

Abstract

The present invention discloses a pearlescent material and method having a pearlescent effect. The pearlescent material comprises the following raw materials: cyclodextrin and gingerol. The method comprises the following steps: S1, preparing a cyclodextrin and gingerol solution; S2, mixing the cyclodextrin solution and the gingerol solution; S3, gradually increasing and decreasing the temperature; S4, cooling, filtering, and standing until the pearlescent material produces supramolecular aggregate crystals. The present invention provides supramolecular aggregated flaky crystals that exhibit stable and obvious pearlescent phenomenon.

Description

Technical Field

[0001] The present invention relates to the technical field of pearlescent materials, in particular to a pearlescent material with pearlescent effect and a method. Background Art

[0002] Pearlescent materials are essentially artificial simulations of a type of luster found in nature, such as natural pearls, shells, butterfly wings, or bird feathers. Pearlite typically has a lamellar structure with interlamellar spacing similar to the wavelength of visible light. Consequently, when visible light strikes such a surface, it exhibits significant interference, diffraction, or reflection, resulting in a soft, unique luster. Pearlescent materials are widely used in powder coatings, architectural coatings, pearlescent inks, pearlescent plastics, and cosmetics, adding an elegant candlelight sheen or metallic effect to products and enriching our visual environment.

[0003] Pearlescent pigments are typically produced by coating multiple layers of metal or metal oxides on top of the color, followed by a calcination process. These coating methods are complex and difficult to precisely control coating uniformity, affecting the desired color and gloss. Patent CN114958036A discloses a pearlescent pigment and its preparation method. This process utilizes an atomic layer deposition process. By controlling the precursor flow rate, deposition time, and deposition times, the thickness of the tungsten layer and adjacent overlying layers can be precisely controlled. A uniform and dense layer of tungsten metal is deposited on the pigment surface, significantly improving both brightness and chromaticity. While the process is simple, the number of repetitions is numerous. Furthermore, the reactor temperature is high, and excess reducing precursors and byproducts must be purged with gas, resulting in significant energy and material consumption, significantly impacting production costs. Furthermore, due to the low density of these pearlescent agents, they often accumulate on the product's upper surface, forming a floating layer that is unsightly for consumers.

[0004] Currently, pearlescent agents primarily include naturally derived shell powder, mica powder, and natural rubber, as well as organic compounds such as higher fatty acids, alcohols, esters, and stearates. Among these, ethylene glycol stearates are the most performant and widely used. Typically, they are combined with ethylene glycol monostearate and ethylene glycol distearate, acting as both a pearlescent agent and a thickener, functioning as an emulsifier, solubilizer, and lubricant. Pearlescent products are often prepared by directly incorporating pearlescent agents to achieve the desired pearlescent effect. However, the incorporation of pearlescent agents can increase the complexity of the formulation, resulting in significant additional costs. Furthermore, due to incompatibility with other ingredients, the inclusion of these pearlescent agents can negatively impact the stability of the resulting formulation. Therefore, the development of alternative crystalline pearlescent agents suitable for a variety of systems, achieving a pearlescent effect without any cross-talk with other ingredients, is crucial. A key focus of the invention in US Patent No. US20100105742A1 is achieving pearlescence in high-fat acid crystals, particularly in formulations containing components such as niacinamide that may inhibit the pearlescent effect. The key approach is to achieve a balance between crystal size, pearlescent effect, and emulsion stability by carefully controlling the addition of alkali metal hydroxide to neutralize fatty acids (i.e., alkali metal soaps), while also monitoring viscosity and temperature. However, this control is challenging, requiring multiple acidification cycles to adjust pH and precise temperature gradients. Furthermore, fatty chain compounds can charge hair, resulting in reduced gloss or a lack of volume. Summary of the Invention

[0005] To address the above problems, the present invention provides a pearlescent material and method with a pearlescent effect. By reacting β-cyclodextrin and gingerol in a certain proportion and controlling the temperature and stirring, uniform supramolecular aggregated lamellar crystals are formed, which exhibit a stable and obvious pearlescent phenomenon.

[0006] To achieve this object, the present invention provides the following technical solutions:

[0007] A first aspect of the present invention provides a pearlescent material having a pearlescent effect. The pearlescent material comprises the following raw materials: cyclodextrin and gingerol.

[0008] Preferably, the cyclodextrin is β-cyclodextrin with a concentration of 0.100-0.001 mol / L.

[0009] Preferably, the gingerol is 6-gingerol.

[0010] Preferably, the molar ratio of cyclodextrin to gingerol is 1:(0.1-20); further preferably, the molar ratio of cyclodextrin to gingerol is 1:(0.2-10); further preferably, the molar ratio of cyclodextrin to gingerol is 1:4.17 or 1:6.25.

[0011] A second aspect of the present invention provides a method for preparing a pearlescent material having a pearlescent effect, comprising the following steps:

[0012] S1, preparing cyclodextrin and gingerol solution;

[0013] S2, mixing the cyclodextrin solution and the gingerol solution;

[0014] S3, gradient heating and cooling;

[0015] S4, cooling, filtering, and standing until a pearlescent material of supramolecular aggregate crystals is produced.

[0016] Preferably, step S3 includes:

[0017] Two stages, the first stage: after stirring at a constant temperature of 40℃-60℃ for 2-5 hours, let it stand at 25℃ for 5-10 hours; the second stage: after stirring at a constant temperature of 40℃-60℃ for 8-12 hours, let it stand at 25℃ for 1-3 hours; or,

[0018] There are three stages. The first stage: stir at a constant temperature of 40℃-60℃ for 2-5 hours, and then let it stand at 25℃ for 5-10 hours. The second stage: stir at a constant temperature of 40℃-60℃ for 8-12 hours, and then let it stand at 25℃ for 5-10 hours. Continue stirring at a constant temperature of 40℃-60℃ for 1-3 hours, and then let it stand at 25℃ for 1-3 hours.

[0019] Preferably, in step S4, the density of the filter used for filtration is 0.22 μm-0.45 μm.

[0020] Preferably, the standing condition is 15-30° C. for 24-48 hours.

[0021] Preferably, the cyclodextrin is β-cyclodextrin with a concentration of 0.100-0.001 mol / L; and the gingerol is 6-gingerol.

[0022] The third aspect of the present invention provides the use of the pearlescent material having a pearlescent effect of the present invention, or the pearlescent material prepared by the method of the present invention in products in the fields of food, beverages, daily chemicals, and biomedical engineering.

[0023] Compared to the prior art, the beneficial effects and significant advancements achieved by applying the technical solution of the present invention are as follows: The present invention aims to provide a method for preparing materials exhibiting aggregation-induced pearlescence through host-guest construction without the introduction of any pearlescent agents and / or surfactants. This method results in a simplified and highly compatible supramolecular self-assembled crystalline pearlescent agent formulation. Furthermore, the present invention boasts high safety, environmental friendliness, and formulation compatibility, making it suitable for use in products requiring pearlescence, such as food, beverages, daily chemicals, and biopharmaceuticals. While also providing uncompromised stability during storage, this method will facilitate the development and application of new materials exhibiting aggregation-induced pearlescence based on cyclodextrin-gingerol host-guest construction in a wider range of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the embodiments of the present invention.

[0025] Figure 1 Liquid pearlescent effect diagram (A) Example 1; (B) Example 2.

[0026] Figure 2 Optical microscope images: (A) Example 1; (B) Example 2.

[0027] Figure 3 Transmission electron microscopy images (A) Example 1; (B) Example 2.

[0028] Figure 4 XRD patterns. (1) β-cyclodextrin; (2) 6-gingerol; (3) Example 1; (4) Example 2. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific examples. The examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes and modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0030] Example 1

[0031] A preparation method of a material with a pearlescent effect constructed from cyclodextrin and gingerol - a three-step gradient heating and / or cooling reaction, specifically comprising the following steps:

[0032] (1) Preparation of β-cyclodextrin aqueous solution: Prepare 0.006 mol / L β-cyclodextrin aqueous solution in a volumetric flask, stir under magnetic heating at 30°C and 300 rpm until completely dissolved, and store at 25°C for later use;

[0033] (2) Weighing gingerol: Weigh gingerol according to the molar ratio of β-cyclodextrin to gingerol of 1:4.17.

[0034] (3) Mixing β-cyclodextrin and gingerol: Add the prepared β-cyclodextrin aqueous solution directly into the container containing gingerol according to the proportion.

[0035] (4) Three-step gradient heating and / or cooling reaction: at 52°C, stir magnetically at 1000 rpm for 5 h, then stop heating and stirring, and let it stand at 25°C for 9 h; heat again at 52°C, stir magnetically at 1000 rpm for 11 h, then stop heating and stirring, and let it stand at 25°C for 10 h; heat a third time at 52°C, stir magnetically at 1000 rpm for 2 h, then stop heating and stirring, and let it stand at 25°C for 3 h.

[0036] (5) Filtration: Aspirate the sample with a 5 ml syringe and filter through a 0.45 μm needle filter membrane (nylon) to obtain a filtrate.

[0037] (6) Standing: Standing at 25°C for 36 hours to wait for the formation of supramolecular aggregate crystals to produce pearlescence.

[0038] Example 2

[0039] A preparation method for a pearlescent material constructed from cyclodextrin and gingerol - a two-step gradient heating and / or cooling reaction, specifically comprising the following steps:

[0040] (1) Preparation of β-cyclodextrin aqueous solution: Prepare 0.004 mol / L β-cyclodextrin aqueous solution in a volumetric flask, stir under magnetic heating at 30°C and 300 rpm until completely dissolved, and store at 25°C for later use;

[0041] (2) Weighing gingerol: Weigh gingerol according to the molar ratio of β-cyclodextrin to gingerol of 1:6.25.

[0042] (3) Mixing β-cyclodextrin and gingerol: Add the prepared β-cyclodextrin aqueous solution directly into the container containing gingerol according to the proportion.

[0043] (4) Two-step gradient heating and / or cooling reaction: at 52°C, stir magnetically at 1000 rpm for 5 h, then stop heating and stirring, and let it stand at 25°C for 9 h; heat again at 52°C, stir magnetically at 1000 rpm for 12 h, then stop heating and stirring, and let it stand at 25°C for 3 h.

[0044] (5) Filtration: Aspirate the sample with a 5 ml syringe and filter through a 0.45 μm needle filter membrane (nylon) to obtain a filtrate.

[0045] (6) Standing: Standing at 25°C for 36 hours to wait for the formation of supramolecular aggregate crystals to produce pearlescence.

[0046] Example 3

[0047] The pearlescent materials prepared in Example 1 and Example 2 were verified according to the following method.

[0048] 3.1 Liquid Pearlescent Effect

[0049] The sample was placed in a 10 mL white transparent centrifuge tube and photographed in a shooting box against a black background to reveal the liquid pearlescent effect by slight shaking. The results are as follows: Figure 1 As shown, Example 1 ( Figure 1 A) and Example 2 ( Figure 1 B) can produce pearlescent effect, and the liquid pearlescent effect of Example 1 is more obvious when distinguished by naked eyes.

[0050] 3.2. The pearlescent materials prepared in Example 1 and Example 2 were analyzed using an Olympus DP74 fluorescence inverted microscope (Olympus VR BX53 microscope, Olympus, Japan) and LC MICRO standard analysis software. 10 μL of the sample was transferred to a clean glass slide using a pipette, and then a cover glass was gently placed on the emulsion droplet for observation. The results are shown in FIG. Figure 2 As shown, under an optical microscope, the crystals in Example 1 mostly have regular flake or block structures. Compared with Example 2, the particles in Example 1 are smaller and more uniform in size, ranging from 5 to 16 μm, and tend to aggregate. In Example 2, the crystals are less aggregated, with a more regular flake-like rhombus shape, but the size uniformity is relatively weak, ranging from 4 to 23 μm.

[0051] 3.3. The pearlescent materials prepared in Example 1 and Example 2 were placed under a projection electron microscope (TEM, JEM-2100plus, Hitachi JEOL) to observe the internal morphology of the samples. Before TEM observation, the samples were dropped onto a 200-mesh copper grid, dried for 20 minutes, and observed at a voltage of 200 kV. The results are as follows: Figure 3 As shown in the TEM image, the lamellae of Example 1 are thicker, while the pearlescent material prepared in Example 2 exhibits a distinct loose and fractured state. The thickness and shape integrity of the crystal lamellae will affect the optical effects of the crystal on light, such as reflection, refraction, or interference, and thus produce varying degrees of pearlescence.

[0052] 3.4. The liquid pearlescent material needs to be frozen in a refrigerator at -80°C for 8 hours, and then vacuum dried at -50°C for 12 hours to obtain a powdered pearlescent material for powder X-ray diffraction (XRD) to determine the formation of inclusion complex crystals. XRD detection is carried out at an operating voltage of 40 kV and an operating current of 40 mA, with a scanning speed of 2° / min in the range of 5–50°. Data collection uses CuKa radiation The diffractometers were carried out on a Bruker D8-VENTURE equipped with a CMOS-based detector PHOTON 100. Figure 4 As shown, by comparing curves 1 (β-cyclodextrin) and 2 (6-gingerol) with curves 3 (Example 1) and 4 (Example 2), it is found that new diffraction peaks appear and characteristic diffraction peaks disappear in curves 3 and 4, confirming the formation of 6-gingerol / β-cyclodextrin inclusion complex, that is, the pearlescent material is a plate-like crystal constructed by the 6-gingerol / β-cyclodextrin inclusion complex unit.

[0053] In summary, pearlescent materials are supramolecular lamellar crystals constructed by 6-gingerol / β-cyclodextrin inclusion complex units. Compared with the two-stage preparation, the three-stage preparation of pearlescent materials has better pearlescent effect.

[0054] The applicant declares that, in the description of the above specification:

[0055] The descriptions of terms such as "this embodiment", "an embodiment of the present invention", "as shown in...", "further", "a further improved technical sub-scheme", etc., mean that the specific features, structures, materials or characteristics described in the embodiment or example are included in at least one embodiment or example of the present invention; in this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials or characteristics described may be combined or combined in an appropriate manner in any one or more embodiments or examples; in addition, a person of ordinary skill in the art may combine or combine different embodiments or examples and features of different embodiments or examples described in this specification without causing any contradiction.

[0056] Finally, it should be noted that:

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same.

[0058] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Non-essential improvements, adjustments or replacements made by those skilled in the art based on the contents of this specification are all within the scope of protection required by the present invention.

Claims

1. A pearlescent material having a pearlescent effect, characterized in that: The pearlescent material comprises the following raw materials: cyclodextrin and gingerol, wherein the cyclodextrin is β-cyclodextrin and the gingerol is 6-gingerol; The preparation method of the pearlescent material comprises the following steps: S1, preparing cyclodextrin and gingerol solution; S2, mixing the cyclodextrin solution and the gingerol solution; S3, gradient heating and cooling; S4, cooling, filtering, and standing until a pearlescent material of supramolecular aggregate crystals is produced; The specific operation of step S3 is as follows: three stages, the first stage: stirring at a constant temperature of 40°C-60°C for 2-5 hours, and then standing at 25°C for 5-10 hours; the second stage: stirring at a constant temperature of 40°C-60°C for 8-12 hours, and then standing at 25°C for 5-10 hours, continuing to stir at a constant temperature of 40°C-60°C for 1-3 hours, and then standing at 25°C for 1-3 hours.

2. The pearlescent material having a pearlescent effect according to claim 1, characterized in that: The molar ratio of the cyclodextrin to the gingerol is 1:(0.1-20).

3. A method for preparing a pearlescent material having a pearlescent effect, characterized in that: The following steps are involved: S1, preparing a cyclodextrin and gingerol solution, wherein the cyclodextrin is β-cyclodextrin and the gingerol is 6-gingerol; S2, mixing the cyclodextrin solution and the gingerol solution; S3, gradient heating and cooling; S4, cooling, filtering, and standing until a pearlescent material of supramolecular aggregate crystals is produced; The specific operation of step S3 is as follows: three stages, the first stage: stirring at a constant temperature of 40°C-60°C for 2-5 hours, and then standing at 25°C for 5-10 hours; the second stage: stirring at a constant temperature of 40°C-60°C for 8-12 hours, and then standing at 25°C for 5-10 hours, continuing to stir at a constant temperature of 40°C-60°C for 1-3 hours, and then standing at 25°C for 1-3 hours.

4. The method for preparing a pearlescent material having a pearlescent effect according to claim 3, wherein: In step S4, the density of the filter used for filtration is 0.22 μm-0.45 μm.

5. The method for preparing a pearlescent material having a pearlescent effect according to claim 3, wherein: In step S4, the standing condition is 15-30° C. for 24-48 hours.

6. Use of the pearlescent material having pearlescent effect according to any one of claims 1 to 2, or the pearlescent material prepared by the method according to any one of claims 3 to 5, in the preparation of daily chemical products.

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