Nano essence capsule, preparation method and application

Abstract

The invention discloses a nano essence capsule, a preparation method and application, and relates to the technical field of nano materials, the preparation method of the nano essence capsule comprises the following steps: preparing mesoporous nano silicon dioxide, and carrying out first modification with a coupling agent to obtain a first intermediate product; modifying the first intermediate product for the second time by using a photosensitizer, and carrying out essence loading under an illumination condition to obtain a second intermediate product; mixing and reacting the second intermediate product with a polymeric monomer to prepare the nano essence capsule. Controllable release of fragrance can be achieved, meanwhile, the fragrance retention time of the fragrance can be prolonged, the fragrance problem of leather products can be effectively solved by adding the fragrance into a treating agent and coating the leather surfaces with the fragrance, and the friction resistance of the leather products can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and in particular to nano-fragrance capsules, their preparation methods, and applications. Background Technology

[0002] Fragrances are a class of small-molecule aroma compounds. Different fragrances can bring out a variety of aromatic scents and are widely used in perfumes, deodorants, and other fields. They can also be used in leather products. However, fragrances are volatile and easily oxidized, resulting in problems such as short fragrance retention time and low efficiency in practical use. Therefore, the design of fragrances as a source of aroma needs to consider the controllability and release rate of volatile substances. That is, the normal release of aroma should not be affected when needed, and the release rate should be moderate. When not needed, the aroma should be prevented from evaporating, thereby improving the efficiency of fragrance use and extending the fragrance retention time. At the same time, attention should also be paid to the protection of fragrance molecules. Currently, there are relevant patents or literature on the preparation of nano-fragrance capsules, but some have failed to achieve controllable release of fragrance. Under continuous release, the fragrance retention time is short. Others, although they have achieved the function of controllable release, have failed to control the release amount. This may result in an overly strong fragrance that causes discomfort and affects the service life of nano-fragrance capsules. In addition, the direct intervention of nanocapsules may also have dispersibility problems, which will affect the scratch resistance of the final leather product. Furthermore, with the increasing awareness of environmental protection, many oil-based production processes have been shifted to water-based processes. Therefore, the hydrophilicity of nano-fragrances is also an important property for their use in solvent-free environments.

[0003] Furthermore, leather can be mainly divided into animal leather and synthetic leather. Animal leather has a distinctive odor characteristic of fur, which cannot be completely eliminated even with processing measures. Additionally, the production process inevitably involves some organic agents, which can also impart unpleasant odors to the finished leather product. Moreover, the main components of animal leather are protein and fat, providing favorable conditions for mold growth. Therefore, it is highly susceptible to mold growth in hot and humid weather, where the proteins react to produce various amines, another source of the unpleasant odor. Synthetic leather production also involves a large amount of organic agents, similarly resulting in an unpleasant odor. Today, leather is widely used in automobiles, clothing, furniture, and other fields, and people are increasingly concerned about its odor. Therefore, leather production often requires adjustments to processes or raw materials to improve the odor of the finished product, which is often time-consuming, labor-intensive, and yields limited results. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes nano-fragrance capsules, preparation methods and applications, which can achieve controlled release of fragrance while improving its fragrance retention time. Adding it to the treatment agent and coating it on the surface of leather can effectively improve the odor problem and friction resistance of leather products.

[0005] The present invention proposes a method for preparing nano-fragrance capsules, the method steps of which are as follows:

[0006] S1: Preparation of mesoporous nano-silica, and first modification with a coupling agent to obtain the first intermediate product;

[0007] S2: The first intermediate product is modified a second time with a photosensitizer and then loaded with fragrance under light conditions to obtain the second intermediate product;

[0008] S3: The second intermediate product is mixed with the polymer monomer to prepare nano-fragrance capsules.

[0009] Preferably, the template agent for preparing S1 mesoporous nano silica is a poly(ethylene oxide-poly(propylene oxide-poly(ethylene oxide)) triblock copolymer and / or hexadecyl pyridine bromide.

[0010] Preferably, the coupling agent in S1 is one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; the solvent used for the first modification is one or more of N,N-dimethylformamide, acetonitrile, and aqueous ethanol solution; the reaction conditions for the first modification are 24 h at 30-70 °C; and the mass-volume ratio of mesoporous nano-silica to the coupling agent is 1 g: 1-3 ml.

[0011] Preferably, the photosensitizer in S2 is one or more of N-hydroxyethyl-3,3-dimethyl-6-nitroindolinespiropyran, 1,3,3-trimethylspiro[indole-2,3'-naphtho[2,1-b][1,4]oxazine], and 4-aminoazobenzene; the solvent used for the second modification is one or more of N,N-dimethylformamide, acetonitrile, and aqueous ethanol solution; the reaction conditions for the second modification are 24 h at 40-80 °C; and the mass ratio of the first intermediate product to the photosensitizer is 1:1-2.

[0012] Preferably, the fragrance in S2 is one or more of jasmine fragrance, rose fragrance, and osmanthus fragrance.

[0013] Preferably, the monomers in S3 are glycidyl methacrylate and dimethylaminoethyl methacrylate in a mass ratio of 2:1-4.

[0014] Preferably, the mass ratio of the second intermediate product to the polymerizing monomer in S3 is 1:10-15; the reaction conditions are 60~100℃ for 24h; and the solvent used in the reaction is one or more of N,N-dimethylformamide, acetonitrile, and aqueous ethanol solution.

[0015] The present invention proposes a nano-fragrance capsule, which is prepared by the above-described method.

[0016] The present invention proposes the application of a nano-fragrance capsule in leather, wherein the nano-fragrance capsule is as described above.

[0017] Preferably, the leather comprises a substrate and a surface treatment layer coated on the surface of the substrate, the surface treatment layer comprising the following raw materials in parts by weight: 100 parts of water-based treatment agent, 3-7 parts of the above-mentioned nano-fragrance capsules, and 4-8 parts of curing agent.

[0018] Beneficial technical effects of the present invention:

[0019] This invention uses nano-silica with a regular spatial group mesoporous structure as a fragrance carrier, modifies it with a photosensitizer, loads the fragrance into the uniform pores inside, and finally modifies the surface with polymers to obtain nano-fragrance capsules with long-lasting aroma retention and controllable release. This photosensitizing structure exhibits cis-trans isomerization, reversibly switching between two states. In darkness, it acts as a barrier to prevent fragrance volatilization, while under light, some groups in the structure rotate, facilitating the release of fragrance molecules, thus achieving the function of artificially controlling fragrance release. The polymer shell formed by soft polymer chains on the surface effectively slows down the fragrance release rate, allowing for fragrance release while avoiding an overly strong and unpleasant aroma, thereby increasing the lifespan of the fragrance capsule and maintaining a continuous aromatic atmosphere. Simultaneously, the silica shell effectively protects the fragrance from oxidation, improving the efficiency of fragrance use.

[0020] The polymer monomers of this invention are composed of glycidyl methacrylate and dimethylaminoethyl methacrylate. On one hand, the epoxy-active sites can form chemical bonds with the hydroxyl groups of leather and the treatment agent, thereby controlling the release rate of fragrance while enhancing the compatibility of the nanocapsules with the leather surface, preventing the nanocapsules from being worn away by external scratches, and improving scratch resistance. On the other hand, the polymer coating enhances the hydrophobicity of the nanoparticles. Therefore, to meet the requirements of water-based processes, the polymer chain is a binary copolymer with cationic hydrophilic groups, which allows the fragrance capsules to be uniformly dispersed in water. This allows them to be mixed in an aqueous treatment agent, and then the treatment agent can be applied to the leather surface to effectively improve the odor problem of traditional leather. Attached Figure Description

[0021] Figure 1This is a diagram illustrating the scratch resistance of the leather product proposed in this invention. Detailed Implementation

[0022] The present invention will be further explained below with reference to specific embodiments.

[0023] The poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer of this invention was purchased from Aladdin Biochemical Technology Co., Ltd.; tetraethyl orthosilicate, hexadecyl bromopyridine, γ-aminopropyltriethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, N-hydroxyethyl-3,3-dimethyl-6-nitroindolinespiropyran, 1,3,3-trimethylspiro[indole-2,3'-naphtho[2,1-b][1,4]oxazine], 4-aminoazobenzene, glycidyl methacrylate, and dimethylaminoethyl methacrylate were purchased from Anaiji Chemical; jasmine fragrance, rose fragrance, and osmanthus fragrance were purchased from Guangdong Mingkang Fragrance & Flavor Co., Ltd.

[0024] Example 1

[0025] 100.0 mL of distilled water and 16.0 mL of concentrated hydrochloric acid were poured into a 250 mL flask. Then, 3.0 g of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer was added and dissolved in the system by ultrasonic vibration. The mixture was then stirred magnetically at 800 rpm for 4.0 h in a 35 °C water bath. Next, 6.32 g of tetraethyl orthosilicate was added dropwise, and the mixture was stirred at 42 °C for 24 h. The mixture was then transferred to a PTFE-lined stainless steel autoclave and kept at 100 °C for 24 h. After cooling to room temperature, the white solid product was filtered off and washed three times with ethanol, then dried overnight under vacuum at 60 °C. Subsequently, the product was heated to 550 °C at a heating rate of 1.8 °C / min and calcined for 6 h to remove the template agent within the pores, yielding mesoporous silica nanoparticles.

[0026] 1.00 g of mesoporous silica was dispersed in an aqueous ethanol solution (V / V = 1 (1)), and then 1 mL of γ-glycidoxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane were added. The mixture was stirred at 50 °C for 24 h. Coupling agent modified mesoporous silica was obtained, washed several times with ethanol, and then dried in a vacuum oven.

[0027] 1g of the intermediate product from the previous step was dispersed in tetrahydrofuran, and then 1g of 4-aminoazobenzene was added. The mixture was refluxed at 80°C for 24h. After the reaction was completed, the mixture was washed with ethanol and dried. The product was then dispersed in osmanthus fragrance solution and stirred and loaded under light for 24h. After filtration, controllable release nano-fragrance capsules were obtained and stored in the dark.

[0028] 1g of nano-fragrance capsules were dispersed in 40mL of N,N-dimethylformamide, and then 10mg of azobisisobutyronitrile and 5mL of glycidyl methacrylate and dimethylaminoethyl methacrylate were added. The mixture was then subjected to vacuum-nitrogen purging and three cycles of degassing. The mixture was then reacted at 70℃ for 24h under nitrogen protection and in the dark to obtain polymer-coated mesoporous silica nano-fragrance capsules.

[0029] Mix 5g of the product from the previous step into 100g of water-based treatment agent, then add 6g of curing agent and mix to obtain a treatment agent layer slurry. Apply the treatment agent layer slurry to the surface of the leather and dry it. Then emboss it to obtain the finished leather product.

[0030] Example 2

[0031] In this solution, the amount of polymer-coated mesoporous silica nano-fragrance capsules used in the treatment agent is 3g, and all other conditions are the same as in Example 1.

[0032] Example 3

[0033] In this treatment, the amount of polymer-coated mesoporous silica nano-fragrance capsules used is 7g, and all other conditions are the same as in Example 1.

[0034] Comparative Example 1

[0035] A treatment agent layer slurry is prepared by mixing 100g of water-based treatment agent, 6g of curing agent, and 5g of uncoated polymer-controlled release nano-fragrance capsules. The treatment agent layer slurry is then used to treat the surface of the leather substrate, followed by embossing to obtain leather.

[0036] Comparative Example 2

[0037] A treatment agent layer slurry is prepared by mixing 100g of water-based treatment agent, 6g of curing agent, and 5g of osmanthus fragrance. The treatment agent layer slurry is then used to treat the surface of the leather substrate, followed by embossing to obtain leather.

[0038] Comparative Example 3

[0039] 100g of water-based treatment agent and 6g of curing agent are mixed to prepare a treatment agent layer slurry. The treatment agent layer slurry is used to treat the surface of the leather substrate, and then embossing is performed to obtain leather.

[0040] Comparative Example 4

[0041] The monomer used in this scheme is glycidyl methacrylate, and all other conditions are the same as in Example 1.

[0042] Comparative Example 5

[0043] The monomer used in this scheme is dimethylaminoethyl methacrylate, and all other conditions are the same as in Example 1.

[0044] The odor of the samples was determined according to ISO 8589:2007 standard. The tests were conducted in odor-free bottles, and each sample was tested in triplicate. The final score was the average value. The main evaluation criteria were the intensity of the irritant odor, the concentration of the aroma, and the leather odor. The specific scoring criteria are shown in Table 1.

[0045] Table 1 Leather Odor Scoring Criteria

[0046]

[0047] The odor of the leathers from Examples 1-3 and Comparative Examples 1-3 was evaluated under light conditions to test the effect of adding fragrance on the leather products. The results are shown in Table 2.

[0048] Table 2 Leather Odor Scoring under Light Conditions

[0049]

[0050] As shown in Table 2, Comparative Example 3, without added fragrance, has a distinct pungent odor and a noticeable leather smell. This is because most raw materials used in leather production have unpleasant odors. In contrast, Examples 1-3, Comparative Example 1, and Comparative Example 2, with added fragrance, exhibit a significantly reduced level of pungent odor and a distinct fragrance that masks the leather smell. This demonstrates that the addition of fragrance effectively improves the odor quality of leather products. Furthermore, the fragrance concentration in Example 1 is significantly lower than that in Comparative Example 1, indicating that the flexible polymer chain shell slows down the release rate of the fragrance, preventing excessive fragrance concentration.

[0051] After the leather samples of Examples 1-3, Comparative Examples 1 and 2 were placed in the dark for 12 hours, the odor of the samples was evaluated in the dark to test the controllability of the controllable release nano-fragrance capsules. The results are shown in Table 3.

[0052] Table 3 Odor scores of samples under dark conditions

[0053]

[0054] As shown in Table 3, compared with the data under light conditions in Table 2, the aroma concentration of Examples 1-3 and Comparative Example 1 with added photosensitive nano-fragrance capsules decreased significantly under dark conditions. This is because the photosensitive structure acts as a barrier under dark conditions, effectively preventing the volatilization of fragrance molecules. However, the aroma concentration of Comparative Example 2, which directly added fragrance, did not change significantly, indicating that the modification of the photosensitizer effectively controlled the release of fragrance.

[0055] After the samples from Examples 1-3, Comparative Examples 1 and 2 were placed under natural conditions for two weeks (natural changes in light and dark cycles), the odor of the samples was evaluated under light conditions to test the long-lasting effect of the nano-fragrance capsules with long aroma retention and controllable release. The results are shown in Table 4.

[0056] Table 4. Leather odor scores under light conditions after two weeks.

[0057]

[0058] As shown in Table 4, Examples 1-3, which incorporated nano-fragrance capsules with long-lasting aroma and controllable release, maintained a higher aroma concentration than Comparative Examples 1 and 2 after two weeks. This is because not only did the natural light-dark cycle reduce the fragrance release time, but the loading of nanomaterials also effectively protected the fragrance from oxidation. Furthermore, the flexible polymer chain shell further delayed fragrance volatilization, significantly improving the fragrance capsule's retention time. In summary, the fragrance capsules prepared by this invention achieve controlled release and control over the fragrance release rate, improving the efficiency and lifespan of the fragrance and better maintaining the aroma quality of leather products for a longer period.

[0059] The nanocapsules prepared in Examples 1-3, Comparative Examples 1, 4, and 5 were dispersed in purified water and allowed to stand for 3 hours. Their dispersion state was observed, and the hydrophilicity of the nanocapsules was tested. The results are shown in Table 5.

[0060] Table 5. Condition of the treatment agent

[0061]

[0062] As shown in Table 5, the nanocapsules prepared in Examples 1-3 and Comparative Example 5 can exist stably in aqueous solution due to the presence of hydrophilic poly(dimethylaminoethyl methacrylate) cationic polymer chains on their surface, which provides a prerequisite for the realization of aqueous processes. In contrast, the nanocapsules without hydrophilic polymer chains exhibit poor dispersibility in water.

[0063] The leathers prepared in Examples 1-3, Comparative Examples 1 and 5 were subjected to finger scratching. The surface condition of the leathers after finger scratching was observed, and the compatibility of the nanocapsules on the leather surface and in the treatment agent after drying was evaluated. The results are shown in Table 6 and 7. Figure 1 As shown.

[0064] Table 6. Leather surface condition after scratching.

[0065]

[0066] In the subsequent drying process, as the solution gradually evaporates, a large number of nanocapsules directly settle onto the surface of the treatment agent. As shown in Table 6, in Examples 1-3, the polyglycidyl methacrylate polymer chains on the surface of the nanocapsules have a large number of epoxy-active sites, which can chemically react with the treatment agent and the hydroxyl groups on the leather to form chemical bonds, resulting in stable existence on the leather surface, and no obvious marks are left when scratched. However, in Comparative Examples 1 and 5, after the nanocapsules are mixed into the treatment agent and treated on the leather surface, there are no chemical bonds, and the surface nanocapsules are easily scraped off. The visual difference between silica and the treatment agent will show obvious scratches, affecting the scratch resistance of the leather. Furthermore, once the surface fragrance capsules are scraped off, the fragrance enhancement effect will be greatly weakened.

[0067] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A method for preparing a nano-fragrance capsule, characterized in that, The method steps are as follows: S1: mesoporous nanosilica is prepared, and a first modification is performed with a coupling agent to obtain a first intermediate product; S2: a second modification is performed on the first intermediate product with a photosensitizer, and fragrance loading is performed under light conditions to obtain a second intermediate product; S3: the second intermediate product is mixed with a polymerization monomer to prepare a nanofragrance capsule.

2. The method for preparing nano-fragrance capsules according to claim 1, characterized in that, In S1, a template agent is polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and / or bromohexadecylpyridine.

3. The method for preparing nano-fragrance capsules according to claim 1, characterized in that, In S1, the coupling agent is one or more of γ-aminopropyl triethoxysilane, γ-glycidyl ether propyl trimethoxysilane and γ-methacryloyl propyl trimethoxysilane; the solvent used for the first modification is one or more of N,N-dimethylformamide, acetonitrile and an ethanol aqueous solution; the reaction conditions for the first modification are 40-80℃ for 24h; and the mass-volume ratio of mesoporous nanosilica to the coupling agent is 1g:1-3ml.

4. The method for preparing nano-fragrance capsules according to claim 1, characterized in that, In S2, the photosensitizer is one or more of N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, 1,3,3-trimethyl spiro[indoline-2,3'-naphtho[2,1-b][1,4]oxazine] and 4-aminoazobenzene; the solvent used for the second modification is one or more of N,N-dimethylformamide, acetonitrile and an ethanol aqueous solution; the reaction conditions for the second modification are 70-100℃ for 24h; and the mass ratio of the first intermediate product to the photosensitizer is 1:1-2.

5. The method for preparing nano-fragrance capsules according to claim 1, characterized in that, In S2, the fragrance is one or more of jasmine fragrance, rose fragrance and hanging flower fragrance.

6. The method of claim 1, wherein the nano-odorant capsule is prepared by the steps of: In S3, the polymerization monomer is glycidyl methacrylate and dimethylaminoethyl methacrylate in a mass ratio of 2:1-4.

7. The method for preparing nano-fragrance capsules according to claim 1, characterized in that, In S3, the mass ratio of the second intermediate product to the polymerization monomer is 1:10-15; the reaction conditions are 60-120℃ for 24h; and the solvent used for the reaction is one or more of N,N-dimethylformamide, acetonitrile and an ethanol aqueous solution.

8. A nanoflavor capsule characterized in that, The nanofragrance capsule is prepared by the preparation method of any one of claims 1-7.

9. Use of a nanocapsule of a perfume in leather, characterized in that, The nanofragrance capsule is as claimed in claim 8.

10. Use of the nanocapsules of the fragrance according to claim 9 in leather, characterized in that, The leather comprises a base body and a surface treatment layer coated on the surface of the base body, and the surface treatment layer contains the following raw materials in parts by weight: 100 parts of an aqueous treatment agent, 4-6 parts of the nanofragrance capsule of claim 8 and 4-8 parts of a curing agent.

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