Photochromic contact lens developing fragrance volatile carriers and methods for making the same

Abstract

The application relates to the technical field of daily aromatherapy and photochromic functional products, and discloses a photochromic invisible fragrance volatile carrier and a preparation method thereof, the preparation method being as follows: pretreatment of degreasing, cleaning and drying is carried out on a porous volatile base material; an invisible pattern is formed on the surface of the pretreated porous volatile base material by using photochromic ink through printing or coating; low-temperature pre-drying is carried out on the printed porous volatile base material, so that the photochromic ink is semi-solidified in the surface layer capillary port of the porous volatile base material, and the ink is prevented from penetrating into the deep micropores in the interior of the porous volatile base material. The ink and the protective layer can only penetrate into 1 / 3 to 1 / 2 of the depth of the surface layer micropores of the porous base material, a surface layer semi-inlaid anchoring structure is formed, the core area in the interior of the base material is reserved as an essential oil volatile channel, and the effect that the carrier is breathable and oil-proof and the basic fragrance diffusion efficiency is not sacrificed is achieved.

Description

Technical Field

[0002] This application relates to the technical field of daily-use fragrances and photochromic functional products, specifically to a photochromic invisible developing fragrance volatile carrier and its preparation method. Background Technology

[0004] With the improvement of living standards, flameless aromatherapy diffusers, as a type of home furnishing product that can continuously emit fragrance and enhance the atmosphere of a space, have been widely welcomed by consumers. Traditional flameless aromatherapy diffuser carriers (such as fiber sticks, rattan, and porous polymer sticks) usually only have the function of adsorbing and evaporating essential oils, and their appearance is mostly solid color, lacking visual interactivity and decorative interest.

[0005] To enhance the competitive differentiation of fragrance products, some volatile carriers with surface patterned prints have emerged on the market. However, these conventional prints are always visible in natural light but invisible in the dark, resulting in a monotonous visual effect and failing to achieve the highly interactive experience of being invisible in daily life but visible under light.

[0006] In recent years, photochromic or UV-excited fluorescent materials have begun to be explored for application in various consumer products. However, directly applying these materials to fragrance volatile carriers faces several technical challenges:

[0007] First, there is a contradiction between oil resistance and stability. Aromatherapy essential oils, as strong solvents, have a strong dissolving and corrosive effect on conventional photochromic inks or fluorescent materials. If the photochromic material is printed directly on the carrier surface, the color layer is very prone to swelling, dissolving, and peeling off during long-term contact with the essential oil, and may even cause the essential oil to become contaminated and cloudy.

[0008] Secondly, there is a contradiction between coating corrosion protection and capillary pore blockage. The common solution in existing technologies is to apply an oil-resistant protective varnish to the outside of the color-changing layer. However, the core function of a fragrance carrier relies on its rich network of microscopic capillary pores. Once a conventional protective topcoat is applied, the capillary pores are easily and completely blocked, preventing the essential oils from evaporating and directly causing the carrier to lose its fundamental function as a fragrance diffuser.

[0009] Third, the conflict between the protective layer and light excitation. Commercially available weather-resistant protective coatings (such as clear varnishes) typically contain UV absorbers in their formulations to prevent substrate aging. Using such coatings as a protective layer directly blocks the excitation of ultraviolet light, preventing the underlying invisible materials from being triggered and rendering the color-developing function completely ineffective. Summary of the Invention

[0011] The purpose of this application is to provide a photochromic invisible developing fragrance volatile carrier and its preparation method, so as to solve the technical problems mentioned in the background art.

[0012] To achieve the above objectives, this application provides the following technical solution: a photochromic invisible developing fragrance evaporator, comprising:

[0013] Porous volatile substrate, invisible photochromic layer disposed on the surface of the porous volatile substrate, and essential oil resistant protective layer covering the outside of the invisible photochromic layer;

[0014] The essential oil-resistant protective layer is a transparent and ultraviolet-transmitting protective coating; the essential oil-resistant protective layer is formed by mixing a transparent ultraviolet-transmitting protective coating with a silane coupling agent added at 0.5%-1.5% of the weight of the protective coating and curing it on the surface of a porous volatile substrate.

[0015] The essential oil-resistant protective layer and the invisible photochromic layer together fill part of the micropores on the surface of the porous volatile substrate, forming a shallow anchoring structure that blocks the penetration of essential oils; wherein, the average penetration depth of the invisible photochromic layer and the essential oil-resistant protective layer in the micropores on the surface of the porous volatile substrate is 1 / 3 to 1 / 2 of the depth of the micropores.

[0016] Preferably, the porous volatile substrate is one or more of the following: porous fiber rods, rattan, reed rods, gypsum, ceramics, and porous polymer materials with hydrophilic modification on the surface that are rich in free hydroxyl groups; the diameter of the porous volatile substrate is 2-12 mm and the length is 100-200 mm.

[0017] Preferably, the material of the invisible photochromic layer is one of colorless ultraviolet-excited fluorescent material, ultraviolet photochromic material, and sunlight-chromic material; the dry film thickness of the invisible photochromic layer is 2-8 μm.

[0018] Preferably, the silane coupling agent is KH-570; the dry film thickness of the essential oil-resistant protective layer is 5-12 μm.

[0019] A method for preparing a photochromic invisible developing fragrance volatile carrier includes the following steps:

[0020] S1. Substrate pretreatment: Degreasing, cleaning, and drying pretreatment of porous volatile substrates;

[0021] S2. Invisible Pattern Printing: Invisible patterns are formed on the surface of a pretreated porous volatile substrate by printing or coating with photochromic ink;

[0022] S3. Low-temperature pre-curing: The printed porous volatile substrate is pre-dried at low temperature, so that the photochromic ink is semi-cured at the surface capillary opening of the porous volatile substrate, preventing the ink from penetrating into the deep micropores inside the porous volatile substrate.

[0023] S4. Protective layer coating and final curing: Add silane coupling agent to the transparent oil-resistant protective coating and mix evenly; apply the mixed coating to the area with the invisible photochromic layer, and after curing, obtain the finished product.

[0024] Preferably, in step S1, the drying pretreatment conditions are baking at 60°C for 20-30 minutes.

[0025] Preferably, in step S2, the viscosity of the photochromic ink at 25°C is 2500-4500 mPa·s; the printing method is screen printing, and the screen used is 250-350 mesh.

[0026] Preferably, in step S3, the low-temperature pre-drying temperature is 50°C and the time is 8-12 minutes.

[0027] Preferably, in step S4, the added silane coupling agent is KH-570, and the addition mass is 0.5%-1.5% of the transparent essential oil-resistant protective coating; the viscosity of the transparent essential oil-resistant protective coating at 25°C is 1500-3000 mPa·s; the coating method is dip coating or spray coating; the curing method is UV curing or hot air curing, the energy of UV curing is 800-1200 mJ / cm², and the conditions for hot air curing are curing at 60-70°C for 10-30 minutes.

[0028] Preferably, the wet film thickness of the photochromic ink is 10-25 μm, and the wet film thickness of the mixed transparent essential oil-resistant protective coating is 8-20 μm. By controlling the wet film thickness and the low-temperature pre-curing in step S3, the average penetration depth of the photochromic ink and the transparent essential oil-resistant protective coating in the micropores of the porous volatile substrate surface is limited to 1 / 3-1 / 2 of the micropore depth.

[0029] Compared with the prior art, the beneficial effects of this application are:

[0030] 1) Under the synergistic effect of ink viscosity of 2500-4500 mPa·s, screen mesh of 250-350 mesh, and protective dry film thickness of 5-12 μm, the ink and protective layer can only penetrate to a depth of 1 / 3 to 1 / 2 of the micropores on the surface of the porous substrate, forming a semi-embedded anchoring structure on the surface. This structure not only utilizes the roughness of the substrate to provide a certain physical interlocking force, but more importantly, it preserves the core area inside the substrate as a channel for essential oil evaporation, achieving the effect of a carrier that is breathable but not oil-permeable, without sacrificing the basic aroma diffusion efficiency.

[0031] 2) This invention incorporates a specially designed low-temperature pre-curing step in its preparation process. This step breaks away from the conventional approach of using volatile solvents, utilizing a specific temperature and time window to induce a polymeric phase transition in the photochromic ink. This allows the photochromic ink to semi-cur at the surface capillary openings of the porous volatile substrate, preventing the ink from penetrating into the deep micropores within the substrate. This mechanism blocks the mutual solubility and edge diffusion of the subsequently applied low-viscosity protective coating with the underlying ink, thus ensuring that the developed pattern after excitation exhibits excellent edge sharpness and clarity.

[0032] 3) This invention incorporates a specific proportion of silane coupling agent in a trace amount into a transparent UV-transmitting protective coating. One end of the coupling agent molecule undergoes dehydration condensation with the free hydroxyl groups on the surface of the porous substrate, while the other end cross-links and entangles with the invisible photochromic layer and the outer protective layer, forming a chemical bond bridge at the three-phase interface. This resists the erosion of essential oil molecules and gives the product a longer service life.

[0033] 4) This invention employs a transparent and UV-transmitting protective coating, avoiding the shortcomings of conventional weather-resistant varnishes that contain UV absorbers and thus shield the excitation light source. This outer layer acts as a targeted filter film, remaining colorless and invisible under indoor natural light and ordinary LED lighting, preventing accidental triggering; however, it only produces a high-saturation display / fluorescence effect when exposed to specific ultraviolet light or direct sunlight, transmitting the excitation wavelength. This highly sensitive triggering mechanism brings highly interactive and differentiated visual experiences to flameless fragrance products. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with specific embodiments.

[0037] The raw materials and reagents used in the following specific embodiments are all commercially available conventional products. In addition: colorless UV-excited fluorescent ink: commercially available, 365nm excitation; transparent oil-resistant protective coating: commercially available, transparent UV-transmitting protective coating; silane coupling agent KH-570: commercially available, industrial grade.

[0038] Example 1

[0039] This embodiment prepares a photochromic invisible developing fragrance volatile carrier, including the following steps:

[0040] S1. Substrate pretreatment: Select porous fiber rods with a diameter of 3mm and a length of 105mm as porous volatile substrates, and bake them in an oven at 60℃ for 20 minutes to perform degreasing and dehumidification pretreatment to ensure surface cleanliness.

[0041] S2. Invisible pattern printing: Using colorless UV-excited fluorescent ink with a viscosity of 2600 mPa·s (25℃), a 250-mesh screen is used to screen print on the upper 50mm area of ​​the pretreated porous fiber rod to form an invisible pattern of the preset text, and the wet film thickness is controlled to be 10μm.

[0042] S3. Low-temperature pre-curing: The printed porous fiber rods are pre-dried at 50°C for 8 minutes to initially fix the ink, and the dry film thickness is 2μm to obtain an invisible photochromic layer;

[0043] S4. Protective Layer Coating and Final Curing: Add silane coupling agent KH-570 to a transparent, oil-resistant protective coating with a viscosity of 1500 mPa·s at a mass ratio of 0.6% and mix ultrasonically until homogeneous. Apply the mixed coating to the area with the invisible photochromic layer, controlling the wet film thickness to 8 μm; then cure with hot air at 60°C for 10 minutes, achieving a dry film thickness of 5 μm. After cooling, perform performance testing. Once qualified, package and store to obtain the finished product.

[0044] Example 2

[0045] This embodiment prepares a photochromic invisible developing fragrance volatile carrier, including the following steps:

[0046] S1. Substrate pretreatment: Select rattan with a diameter of 4.5mm and a length of 150mm as a porous volatile substrate, put it in an oven at 60℃ and bake for 25 minutes to perform degreasing and dehumidification pretreatment to ensure surface cleanliness;

[0047] S2. Invisible pattern printing: Using colorless UV-excited fluorescent ink with a viscosity of 3400 mPa·s (25℃), a 300-mesh screen is used to screen print on the upper 50mm area of ​​the pretreated rattan to form an invisible pattern with a preset pattern, and the wet film thickness is controlled to be 18μm.

[0048] S3. Low-temperature pre-curing: Place the printed rattan at 50℃ for 10 minutes to pre-dry the ink, so that the dry film thickness is 5μm, and an invisible photochromic layer is obtained.

[0049] S4. Protective Layer Coating and Final Curing: Add silane coupling agent KH-570 to a transparent, oil-resistant protective coating with a viscosity of 2200 mPa·s at a mass ratio of 1.2% and mix thoroughly. Lightly spray the mixed coating onto the area with the invisible photochromic layer, controlling the wet film thickness to 15 μm; then cure using a UV curing device with a UV curing energy of 1000 mJ / cm², achieving a dry film thickness of 8 μm. After cooling, the finished product is obtained.

[0050] Example 3

[0051] This embodiment prepares a photochromic invisible developing fragrance volatile carrier, including the following steps:

[0052] S1. Substrate pretreatment: Select a porous polymer material with a diameter of 8mm and a length of 195mm as a porous volatile substrate, and bake it in an oven at 60℃ for 30 minutes to perform degreasing and dehumidification pretreatment to ensure surface cleanliness.

[0053] S2. Invisible pattern printing: Using UV photochromic ink with a viscosity of 4500 mPa·s (25℃), a 350 mesh screen is used to screen print on the upper 50mm area of ​​the pretreated substrate to form an invisible pattern with a preset mark, and the wet film thickness is controlled to be 25μm.

[0054] S3. Low-temperature pre-curing: The printed substrate is pre-dried at 50°C for 12 minutes to initially fix the ink, and the dry film thickness is 8μm, thus obtaining an invisible photochromic layer;

[0055] S4. Protective Layer Coating and Final Curing: Add silane coupling agent KH-570 to a transparent, oil-resistant protective coating with a viscosity of 3000 mPa·s at a mass ratio of 1.4% and mix thoroughly. Apply the mixed coating to the area with the invisible photochromic layer, controlling the wet film thickness to 20 μm; then cure with hot air at 70°C for 30 minutes, achieving a dry film thickness of 12 μm. After cooling, the finished product is obtained.

[0056] Comparative Example 1 (without essential oil-resistant protective layer) The difference between this comparative example and Example 2 is that step S4 is omitted, that is, it is directly used as the finished product after the low temperature pre-curing in S3, without a transparent essential oil-resistant protective layer.

[0057] Comparative Example 2 (Missing Low Temperature Pre-curing Step) The difference between this comparative example and Example 2 is that the low temperature pre-curing step S3 is omitted. After printing in S2, the protective layer in S4 is directly sprayed and finally cured.

[0058] Comparative Example 3 (Ink viscosity is not within the scope of this application) The difference between this comparative example and Example 2 is that in step S2, the viscosity of the colorless UV-excited fluorescent ink used was adjusted to 800 mPa·s (too low), while the other steps and parameters were the same as in Example 2.

[0059] Comparative Example 4 (The protective layer uses a conventional UV-blocking coating) The difference between this comparative example and Example 2 is that in step S4, the transparent UV-transmitting protective coating is replaced with a commercially available transparent clear varnish containing UV absorbers, and KH-570 is not added. The remaining steps and parameters are the same.

[0060] Performance Testing: The fragrance evaporation carriers prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to the following performance tests. A blank rattan cane of the same specifications, without any printing or coating treatment, was selected as a blank control group.

[0061] (1) Visual color development and pattern clarity test: The appearance of each group of samples was observed under natural indoor light; then, the upper printed area of ​​the sample was irradiated with a 365nm ultraviolet lamp to observe the development effect and edge clarity. The test results are shown in Table 1.

[0062] Table 1: Visual effects and pattern clarity test.

[0063] Example 1 Colorless, completely invisible Instantly activates fluorescence, making the text appear clear. Sharp edges, no smudging Example 2 Colorless, completely invisible Instantly ignites fluorescence, producing a clear pattern. Sharp edges, no smudging Example 3 Colorless, completely invisible Instant color change and clear labeling Sharp edges, no smudging Comparative Example 1 Colorless, completely invisible Instantly ignites fluorescence, producing a clear pattern. Sharp edges, no smudging Comparative Example 2 Colorless, completely invisible Fluorescence is instantly triggered, blurring the pattern. Severe smearing and diffusion at the edges Comparative Example 3 Colorless, completely invisible The color rendering is extremely weak. Ink spreads into deep pores Comparative Example 4 Colorless, completely invisible No color development / luminescence phenomenon /

[0064] As shown in Table 1, Examples 1-3 exhibited clear color development and sharp edges after light exposure, while the pattern in Comparative Example 2 was severely blurred. The core mechanism lies in the absence of the "low-temperature pre-curing (50℃ × 8-12 min)" step specifically designed in this invention. The pre-curing step in this invention is not only for solvent evaporation, but more importantly, it utilizes this specific temperature and time window to induce a phase change in the polymer resin within the photochromic ink. This allows the photochromic ink to semi-cur at the surface capillary openings of the porous volatile substrate, preventing the ink from penetrating into the deep micropores within the substrate. This effectively prevents the subsequent application of a low-viscosity protective coating from mixing with the uncured ink and from edge penetration and diffusion, making it a key process for ensuring the high clarity of the hidden pattern.

[0065] (2) Essential oil resistance and volatility test: Each group of samples (including the blank control group) was inserted into a glass bottle containing an equal amount of standard flameless aromatherapy essential oil and continuously soaked for 30 days. Observe whether the essential oil changes color or becomes cloudy, and whether the printed pattern peels off or dissolves. On the 7th day, the amount of essential oil volatilized (weight loss) of each group was recorded. With the volatilization amount of the blank control group as 100%, the relative volatility of each group was calculated. The test results are shown in Table 2.

[0066] Table 2: Essential oil resistance and volatility test.

[0067] Blank control group Clear, without discoloration / 100% Example 1 Clear, without discoloration The coating is intact and the color develops normally under light. 97.5% Example 2 Clear, without discoloration The coating is intact and the color develops normally under light. 98.1% Example 3 Clear, without discoloration The coating is intact and the color develops normally under light. 96.8% Comparative Example 1 It became cloudy and showed fluorescent contamination. The ink dissolves and peels off in large quantities, causing color development failure. 98.5% Comparative Example 2 Clear, without discoloration The coating is intact, but the color appears blurry under light. 96.5% Comparative Example 3 Clear, without discoloration The coating is intact, but the color development under light is weak. 72.4% Comparative Example 4 Clear, without discoloration The coating is intact and does not show color when exposed to light. 97.0%

[0068] As shown in Table 2, Comparative Example 1 failed after 30 days because the fluorescent ink was completely dissolved by the essential oil due to the lack of an essential oil-resistant protective layer. In contrast, Examples 1-3 maintained normal color development under light even after 30 days of immersion, and the essential oil remained clear. This is not only due to the physical isolation of the protective layer, but more importantly, to the specially designed micro-composite materials in the protective layer of this invention: the addition of 0.5%-1.5% of the silane coupling agent KH-570. The porous fiber / rattan substrate surface is rich in hydroxyl groups. One end of the coupling agent dehydrates and condenses with the hydroxyl groups on the substrate surface, while the other end crosslinks with the outer protective layer and the inner fluorescent ink, forming a chemical bond bridge. This solves the technical bottleneck of traditional commercially available materials easily swelling and falling off in fragrance essential oils.

[0069] (3) Multi-light source excitation comparison experiment: Objective: To verify the uniqueness and sensitivity of the color development triggering conditions. Procedure: The diffuser sticks of Examples 1-3 and Comparative Examples 1-4 were placed under ordinary LED lighting (normal state), D65 standard artificial daylight (simulating indoor natural light), and 365nm / 395nm specific wavelength ultraviolet lamps, respectively. The color development state under different light source conditions was recorded. The test results are shown in Table 3.

[0070] Table 3: Comparison test of excitation from multiple light sources.

[0071] Example 1 Colorless Invisibility Colorless Invisibility Instantly stimulated development, text is clear Example 2 Colorless Invisibility Colorless Invisibility Instant excitation and development, clear pattern Example 3 Colorless Invisibility Colorless Invisibility Instantaneous excitation and development, clear marking Comparative Example 1 Colorless Invisibility Colorless Invisibility Instant excitation and development, clear pattern Comparative Example 2 Colorless Invisibility Colorless Invisibility It was activated instantly, but the pattern was blurry. Comparative Example 3 Colorless Invisibility Colorless Invisibility The color rendering is extremely weak. Comparative Example 4 Colorless Invisibility Colorless Invisibility No color development / luminescence phenomenon was observed.

[0072] As shown in Table 3, Examples 1-3 remained invisible under both ordinary LED lighting and D65 indoor natural light, only becoming visible under specific ultraviolet light sources. Comparative Example 4 used a commercially available clear varnish, which typically contains ultraviolet absorbers to prevent UV aging, preventing the internal fluorescent layer from receiving light and resulting in a complete loss of color rendering. This demonstrates that the specially selected transparent ultraviolet-transmitting protective coating of this invention precisely acts as a targeted filter, neither blocking the ultraviolet excitation band nor interfering with everyday indoor diffuse reflection light, achieving a highly contrasting and uniquely sensitive interactive visual experience.

[0073] (4) Photo-induced fatigue and repeated triggering experiment: Objective: To verify the service life and cycle performance of the color-developing material. Since Comparative Examples 2-4 already had obvious defects in the initial color development stage, this group of experiments focused on examining the durability of Examples 1-3 and Comparative Example 1. Procedure: The above-mentioned diffuser sticks soaked in essential oil were placed in the ultraviolet aging test chamber, and the cycle was set to "10 minutes of ultraviolet irradiation on - 30 minutes of normal return on". After several cycles, the color development state and color saturation under ultraviolet excitation were measured again. The test results are shown in Table 4.

[0074] Table 4: Photo-induced fatigue and repeated triggering durability test.

[0075] Example 1 Clear and sharp color rendering, strong light emission The colors are clear and sharp, with no visible color decay. Clear color rendering with only very slight attenuation and strong interactivity Example 2 Clear and sharp color rendering, strong light emission The colors are clear and sharp, with no visible color decay. Clear color rendering with only very slight attenuation and strong interactivity Example 3 Clear and sharp color rendering, strong light emission The colors are clear and sharp, with no visible color decay. The colors are clear and bright, with only slight fading, and highly interactive. Comparative Example 1 Clear and sharp color rendering, strong light emission The color development is significantly weakened, and the ink is accompanied by leaching contamination. Color development completely failed, and the coating peeled off over a large area.

[0076] As shown in Table 4, after up to 500 cycles of high-intensity cyclic aging tests involving UV irradiation and subsequent restoration to normal operation, the color development of Examples 1-3 remained clearly visible with almost no visible attenuation; while Comparative Example 1, lacking a dedicated protective layer, showed complete color failure, with large areas of coating peeling off. This further confirms the synergistic stability between the outer UV-transmitting protective film and the underlying invisible ink of this invention. The protective layer prevents essential oil molecules from entering the molecular gaps of the photochromic material, avoiding the quenching and photo-oxidative degradation of luminescent groups in the solvent environment, and endowing the volatile carrier with resistance to photo-fatigue.

[0077] (5) Dynamic Comparison Experiment of Evaporation Efficiency and Porosity: Objective: To prove that the basic aroma diffusion function was not sacrificed after adding the protective layer and color developing material. Procedure: Two parallel control groups were set up. Group A was a commercially available ordinary porous fiber aroma diffuser stick of the same material (i.e., an untreated blank substrate), and Group B was a UV-developed aroma diffuser stick prepared in Example 1. The two groups were inserted into glass bottles containing equal amounts of the same essential oil and placed in a constant temperature and humidity environment (25℃, 60% relative humidity). For 7 consecutive days, the overall weight change of the essential oil bottle was weighed every 24 hours, the cumulative amount of essential oil volatilized was recorded, and the change in volatilization rate was plotted. The test results are shown in Table 5.

[0078] Table 5: Dynamic Monitoring of Cumulative Evaporation of Essential Oils (Unit: g)

[0079] Day 1 1.60 g 1.55 g 96.2% Day 3 4.50 g 4.40 g 98.1% Day 5 7.20 g 7.00 g 95.9% Day 7 10.00 g 9.75 g 97.2%

[0080] As shown in Table 5, the relative evaporation efficiency of Examples 1-3 is as high as 96% or more, and their dynamic evaporation rate curves (Group A and Group B in Table 5) almost completely overlap; while the evaporation efficiency of Comparative Example 3 (using a low-viscosity ink of 800 mPa·s) drops to 72.4%. The present invention utilizes a synergistic combination of ink viscosity 2500-4500 mPa·s, screen printing 250-350 mesh, and protective dry film 5-12 μm. Within this range, the ink and protective liquid can only penetrate to a depth of 1 / 3 to 1 / 2 of the micropores on the surface of the porous substrate. This structure allows the core area and deep microporous channels inside the substrate to be preserved as much as possible.

[0081] The penetration depth of the invisible photochromic layer and the essential oil-resistant protective layer in the micropores of the porous volatile substrate can be measured by the following method: After cutting along the cross-section of the porous volatile substrate, the penetration boundary of the resin-cured layer in the pores of the substrate is observed using a scanning electron microscope (SEM) at a magnification of 500-2000 times. Combined with energy dispersive spectroscopy (EDS) to perform line scanning of silicon (derived from silane coupling agent KH-570), the depth d1 of the co-penetration area of ​​the protective layer and ink is determined. By comparing it with the overall radial depth (or overall thickness) d0 of the porous volatile substrate, the penetration ratio d1 / d0 is calculated.

[0082] In summary, this invention successfully overcomes the core defects of traditional color developing materials, such as easy failure and easy clogging of capillaries in a fragrance environment, and endows the product with a long-lasting, stable and highly interactive developing effect without sacrificing the basic fragrance diffusion function.

[0083] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0085] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A photochromic invisible developing fragrance evaporator, characterized in that, include: Porous volatile substrate, invisible photochromic layer disposed on the surface of the porous volatile substrate, and essential oil resistant protective layer covering the outside of the invisible photochromic layer; The essential oil-resistant protective layer is a transparent and ultraviolet-transmitting protective coating; the essential oil-resistant protective layer is formed by mixing a transparent ultraviolet-transmitting protective coating with a silane coupling agent added at 0.5%-1.5% of the weight of the protective coating and curing it on the surface of a porous volatile substrate. The essential oil-resistant protective layer and the invisible photochromic layer together fill part of the micropores on the surface of the porous volatile substrate, forming a shallow anchoring structure that blocks the penetration of essential oils; wherein, the average penetration depth of the invisible photochromic layer and the essential oil-resistant protective layer in the micropores on the surface of the porous volatile substrate is 1 / 3 to 1 / 2 of the depth of the micropores.

2. The photochromic invisible developing fragrance evaporator according to claim 1, characterized in that: The porous volatile substrate is one or more of the following: porous fiber rods, rattan, reed rods, gypsum, ceramics, and high molecular porous materials with hydrophilic modification of the surface to be rich in free hydroxyl groups; the diameter of the porous volatile substrate is 2-12 mm and the length is 100-200 mm.

3. The photochromic invisible developing fragrance evaporator according to claim 1, characterized in that: The material of the invisible photochromic layer is one of colorless ultraviolet-excited fluorescent material, ultraviolet photochromic material, and sunlight-chromic material; the dry film thickness of the invisible photochromic layer is 2-8 μm.

4. The photochromic invisible developing fragrance evaporator according to claim 1, characterized in that: The silane coupling agent is KH-570; the dry film thickness of the essential oil resistant protective layer is 5-12 μm.

5. A method for preparing a photochromic invisible developing fragrance volatile carrier as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Substrate pretreatment: Degreasing, cleaning, and drying pretreatment of porous volatile substrates; S2. Invisible Pattern Printing: Invisible patterns are formed on the surface of a pretreated porous volatile substrate by printing or coating with photochromic ink; S3. Low-temperature pre-curing: The printed porous volatile substrate is pre-dried at low temperature, so that the photochromic ink is semi-cured at the surface capillary opening of the porous volatile substrate, preventing the ink from penetrating into the deep micropores inside the porous volatile substrate. S4. Protective layer coating and final curing: Add silane coupling agent to the transparent oil-resistant protective coating and mix evenly; apply the mixed coating to the area with the invisible photochromic layer, and after curing, obtain the finished product.

6. The preparation method according to claim 5, characterized in that: In step S1, the drying pretreatment conditions are baking at 60°C for 20-30 minutes.

7. The preparation method according to claim 5, characterized in that: In step S2, the viscosity of the photochromic ink at 25°C is 2500-4500 mPa·s; the printing method is screen printing, and the screen used is 250-350 mesh.

8. The preparation method according to claim 5, characterized in that: In step S3, the low-temperature pre-drying temperature is 50°C and the time is 8-12 minutes.

9. The preparation method according to claim 5, characterized in that: In step S4, the added silane coupling agent is KH-570, and the addition mass is 0.5%-1.5% of the transparent essential oil-resistant protective coating; the viscosity of the transparent essential oil-resistant protective coating at 25°C is 1500-3000 mPa·s; the coating method is dip coating or spray coating; the curing method is UV curing or hot air curing, the energy of UV curing is 800-1200 mJ / cm², and the conditions for hot air curing are curing at 60-70°C for 10-30 minutes.

10. The preparation method according to any one of claims 5-9, characterized in that: The wet film thickness of the photochromic ink is 10-25 μm, and the wet film thickness of the mixed transparent essential oil-resistant protective coating is 8-20 μm. By controlling the wet film thickness and the low-temperature pre-curing in step S3, the average penetration depth of the photochromic ink and the transparent essential oil-resistant protective coating in the micropores of the porous volatile substrate surface is limited to 1 / 3-1 / 2 of the micropore depth.