Thermal response type microcapsule perfume and preparation method thereof

Abstract

The invention relates to the technical field of microcapsule encapsulation, and a novel preparation method is adopted to prepare microcapsule perfume. The microcapsule takes natural gelatin and paraffin as composite wall materials, a gradient structure is formed by optimizing the mass ratio (1: 2.5-1: 3.75), the gelatin provides mechanical support, and the paraffin endows hydrophobicity and thermal control release characteristics. Dissolving a solution in which the mass volume ratio of gelatin to water is (1: 2.5)-(1: 3) under an ultrasonic condition; mixing the molten paraffin with the liquid spice and the emulsifier to form an oil phase; the oil phase and the gelatin solution are mixed through magnetic stirring at the rotating speed larger than or equal to 800 rpm till the solid phase and the liquid phase are completely fused; after cooling and curing, separating to obtain the solid microcapsule. And when the temperature reaches the melting point (45-65 DEG C) of paraffin, the wall material is molten and quickly releases the perfume, and the slow release performance is excellent at normal temperature. The material is wide in application field and high in compatibility, and has the advantages of being green, safe, high in environmental stability and controllable in trigger release.

Description

Technical Field

[0001] The invention belongs to the technical field of microcapsule encapsulation, and particularly relates to a heat-responsive microcapsule fragrance using natural gelatin and paraffin as composite wall materials and a preparation method thereof. Background Art

[0002] Fragrances, as volatile aromatic substances, are widely used in perfumes, skincare products, detergents, and food. However, their volatility causes their aroma to rapidly fade during use, impacting product durability and user experience. Therefore, controlling the release rate of fragrances and extending their scent duration has become a key research topic.

[0003] Chinese invention patent CN201710396691.5 proposes a method for preparing microencapsulated fragrances using an emulsified solvent volatilization method. The method involves dissolving the fragrance and wall material in an organic solvent, dispersing the mixture in an aqueous phase, and removing the organic solvent by volatilization to form microcapsules. While this method effectively reduces fragrance volatility, it requires a large amount of organic solvent during the preparation process, resulting in environmental pollution and high costs. Chinese invention patent CN202310025874.1 utilizes an in-situ polymerization method to prepare fragrance microcapsules, using a methylated melamine resin prepolymer as the wall material. The addition of stabilizers and formaldehyde scavengers improves the stability and safety of the fragrance capsules. However, this method requires high equipment requirements and harsh reaction conditions, limiting its large-scale industrial production. Chinese invention patent CN202310884515 utilizes a temperature-sensitive material as the wall material to prepare microencapsulated fragrances via spray drying. While this method can achieve sustained release of fragrances, the high cost of temperature-sensitive materials and the strict temperature control requirements make it difficult to adapt to complex operating environments. There is an urgent need to develop a natural wall material microcapsule with high encapsulation efficiency, moisture resistance and temperature-triggered release; avoid the use of toxic cross-linking agents and simplify the preparation process. Summary of the Invention

[0004] To solve the above problems, the present invention provides a natural wall material microcapsule with high encapsulation efficiency, moisture resistance and temperature-triggered release and a preparation method thereof; avoids the use of toxic cross-linking agents and simplifies the preparation process.

[0005] To achieve the above objectives, the present invention provides a thermally responsive microencapsulated fragrance comprising a core material and a composite wall material, wherein the core material comprises a liquid fragrance; and the composite wall material comprises a coating layer formed by fusing gelatin and paraffin wax through ultrasonic dispersion and magnetic stirring, wherein the mass ratio of gelatin to paraffin wax is between 1:2.5 and 1:3.75. A higher mass ratio results in difficulty in solidifying the product, while a lower mass ratio results in incomplete encapsulation.

[0006] The above-mentioned heat-responsive microcapsule fragrance is characterized in that: the liquid fragrance is essential oil, the core material loading is 10%-15% (w / w); the melting point of the paraffin is 45-65°C, and the surface coverage is 80%-95%.

[0007] The above-mentioned heat-responsive microcapsule fragrance is characterized in that the particle size of the microcapsules is 10-200 μm.

[0008] The method for preparing the above-mentioned heat-responsive microcapsule fragrance is characterized by comprising:

[0009] 1) Dissolving a gelatin to water solution with a mass to volume ratio of 1:2.5 to 1:3 under ultrasonic conditions;

[0010] 2) mixing molten paraffin wax with liquid fragrance and emulsifier to form an oil phase;

[0011] 3) mixing the oil phase and the gelatin solution by magnetic stirring at a speed of ≥800 rpm until the solid and liquid phases are completely fused; cooling and solidifying, and separating to obtain solid microcapsules.

[0012] In the above preparation method, in step 1), the ultrasonic dissolution conditions are power 100-200W and frequency 40kHz.

[0013] In the above preparation method, in step 2), the emulsifier is a Tween series, and the addition amount is 0.1%-0.5% of the total mass of the oil phase;

[0014] In the above preparation method, in step 3), the cooling method is water-insulated cooling, the temperature is ≤25°C, and the time is ≥5 minutes.

[0015] Application of the above-mentioned thermal responsive microcapsule fragrance in the field of fragrance and / or cosmetics.

[0016] The embedding rate of the microcapsules obtained by the invention can reach over 90%, which can slow down the volatilization of spices and prolong the use time of products such as perfumes and aromatherapy.

[0017] When the temperature of the hot compress reaches above 35℃, the release of spices is triggered, and combined with the hot compress effect, it can better relieve muscle pain.

[0018] Positive effects of the present invention

[0019] The particle size is controlled between 100-500μm. By precisely controlling the particle size range of the capsule, it exhibits excellent adaptability in different application scenarios. For example, in fragrance sustained-release applications, the uniform particle size distribution ensures stable aroma release and avoids sudden concentration drops within a short period of time. In medical hot compress applications, the small particle size facilitates release, precisely delivering hot compress essential oils and effectively alleviating symptoms.

[0020] At room temperature (25°C), the 30-day release rate is less than 10%, demonstrating excellent stability under conventional storage conditions, effectively delaying the release and oxidation of the core material. This feature not only significantly extends the product's shelf life but also reduces the complexity of transportation and warehousing, allowing it to maintain stable performance without the need for special environmental control, providing reliable guarantees for commercial applications.

[0021] The microcapsules remained intact even in extremely humid environments with a relative humidity (RH) of 80% for seven days, avoiding performance degradation due to moisture absorption and swelling. This feature not only broadens the product's application scenarios but also enhances its reliability in complex environments, laying the foundation for cross-sector applications. DETAILED DESCRIPTION

[0022] 1. Product structure

[0023] Core material: Liquid fragrances such as tea tree oil and menthol are used, and the core material loading is precisely controlled at 10%-15% (mass percentage). This loading range has been carefully researched and determined to ensure that the microcapsules can release sufficient fragrance to exert their intended efficacy while also maintaining the stability and structural integrity of the microcapsules.

[0024] Composite wall material: A double-layer composite wall material structure achieves an optimized combination of functions. The inner layer is gelatin. With its unique physical and chemical properties, gelatin provides solid mechanical support for the microcapsules, effectively maintaining the microcapsule's morphological stability and making it resistant to deformation under various conditions. The outer layer is paraffin wax, with a melting point set between 45-65°C and a coverage rate of ≥80%. This high coverage of paraffin wax not only effectively isolates the core material from the external environment, preventing volatilization and oxidation of the core material, but also enables precise control of the core material's release under specific temperature conditions.

[0025] 2. Preparation Method

[0026] Step 1: Prepare the gelatin solution: Mix gelatin and deionized water in a mass-to-volume ratio of 1:2.5-1:3. Dissolve the gelatin solution at 40-60°C using an ultrasonic power of 100-200W. The appropriate temperature and ultrasonic power promote the uniform dispersion of gelatin molecules, allowing them to fully dissolve in the deionized water, forming a uniform and stable gelatin solution, which lays a good foundation for subsequent microcapsule preparation.

[0027] Step 2: Oil Phase Preparation: First, heat the paraffin wax to 60-80°C to melt it, creating conditions for uniform mixing of subsequent ingredients. Then, add the core material and a Tween-based emulsifier (0.1%-0.5% by weight of the oil phase). Ultrasonic mixing is used to fully blend the ingredients, forming a stable oil phase system. The addition of the emulsifier reduces the interfacial tension between the oil and water phases, promoting uniform mixing and improving the quality of the microcapsule preparation.

[0028] Step 3: Emulsification and Solidification: Slowly inject the prepared oil phase into the gelatin solution while stirring with a magnetic stirrer at a speed of ≥800 rpm for 10-30 minutes to ensure full contact and uniform mixing of the oil phase and gelatin solution, achieving solid-liquid fusion. This is followed by water-cooling, maintaining the temperature at ≤25°C for ≥5 minutes. The cooling process causes the gelatin to solidify, forming a microcapsule structure that encapsulates the core material. Finally, drying removes excess water from the microcapsules to obtain the finished microcapsules.

[0029] Example 1: Citrus essential oil microcapsules

[0030] 1. Raw materials:

[0031] Gelatin 8g, deionized water 20ml; paraffin 7.5g (melting point 52°C), citrus essential oil 2ml, Tween-80 0.05g.

[0032] 2. Craftsmanship:

[0033] Preparation of gelatin solution: In a 50°C water bath, add 8g of gelatin to 20ml of deionized water and use a 150W, 40kHz ultrasonic disperser to ultrasonically dissolve the gelatin until it is completely dissolved to form a uniform gelatin solution. Preparation of oil phase: Melt 7.5g of paraffin at 60°C, then add 2ml of citrus essential oil and 0.05g of Tween-80, and use an ultrasonic disperser to ultrasonically mix to ensure that the essential oil and Tween are evenly dispersed in the paraffin. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200rpm using a magnetic stirrer for 15 minutes. At the same time, cool to 20°C in water to allow the mixture to solidify and form microcapsules.

[0034] 3. Test results:

[0035] Particle size was determined to be 120±30 μm using a laser particle size analyzer. Aroma release test: After 30 days at room temperature (25°C), 10 mg of microcapsules were added to 50 mL of release medium. The mixture was shaken at a constant temperature. 1 mL of the supernatant was sampled periodically and the characteristic absorption peak intensity was measured using a UV spectrophotometer. The release rate was determined to be 8%. After 2 hours in a 60°C incubator, 10 mg of microcapsules were added to 50 mL of release medium. The mixture was shaken at a constant temperature. 1 mL of the supernatant was sampled periodically and the characteristic absorption peak intensity was measured using a UV spectrophotometer. The release rate was determined to be 83%.

[0036] Humidity resistance (RH 80%) test: No cracking after being placed in an environment with a relative humidity of 80% for 30 days.

[0037] Comparative Example 1-1: Single gelatin wall material

[0038] For microcapsules made from a single gelatin wall material, 8g of gelatin was added to 20mL of deionized water in a 50°C water bath and ultrasonically dissolved using a 150W, 40kHz ultrasonic disperser until the gelatin was completely dissolved, forming a uniform gelatin solution. 2mL of citrus essential oil was added and ultrasonically mixed using an ultrasonic disperser to ensure uniform dispersion of the essential oil in the gelatin. The resulting product had a relatively larger particle size and a wider distribution range. Aroma release was faster at both room and elevated temperatures. After 30 days at room temperature, the release rate was 30%, which is not conducive to sustained aroma release. Stability was poor in an environment with a relative humidity of 80%, with the particles rupturing after 15 days due to water absorption.

[0039] Comparative Example 1-2: Multi-paraffin wall material

[0040] Preparation of gelatin solution: In a 50°C water bath, add 2.5g of gelatin to 20ml of deionized water and use a 150W, 40kHz ultrasonic disperser to ultrasonically dissolve the gelatin until it is completely dissolved to form a uniform gelatin solution. Preparation of oil phase: Melt 7.5g of paraffin at 60°C, then add 2mL of citrus essential oil and 0.05g of Tween-80, and use an ultrasonic disperser to ultrasonically mix to ensure that the essential oil and Tween are evenly dispersed in the paraffin. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200rpm using a magnetic stirrer for 15min. At the same time, cool to 20°C in water to allow the mixture to solidify and form microcapsules.

[0041] After being placed at room temperature for 30 days, the release rate was 42%, the pores of the wall material were large, and the core material seeped out slowly. After being placed at 60°C for 2 hours, the release rate was 58%, the paraffin layer was too thick, and the diffusion of the core material was hindered after melting. After being placed at RH80% for 15 days, microscopic observation showed that oil seeped out of the surface, there was insufficient gelatin, and the wall material coating was incomplete.

[0042] Comparative Examples 1-3: Multi-gelatin wall material

[0043] Preparation of gelatin solution: In a 50°C water bath, add 9g of gelatin to 20mL of deionized water and use a 150W, 40kHz ultrasonic disperser to ultrasonically dissolve the gelatin until it is completely dissolved to form a uniform gelatin solution. Preparation of oil phase: Melt 3g of paraffin at 60°C, then add 2mL of citrus essential oil and 0.05g of Tween-80, and use an ultrasonic disperser to ultrasonically mix to ensure that the essential oil and Tween are evenly dispersed in the paraffin. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200rpm using a magnetic stirrer for 15min. At the same time, cool to 20°C in water to allow the mixture to solidify and form microcapsules.

[0044] After being placed at room temperature for 30 days, the release rate was 12%, the gelatin layer was dense, and the sustained release property was good. After being placed at 60℃ for 2 hours, the release rate was 65%, the paraffin was insufficient, and the heat triggering efficiency was low. After being placed at RH80% for 7 days, the microcapsules swelled and ruptured, the paraffin hydrophobic layer was too thin, and the moisture barrier failed.

[0045] Example 2: Menthol Microcapsules

[0046] 1. Raw materials:

[0047] Gelatin 10g, paraffin 15g (melting point 58°C), menthol 3ml.

[0048] 2. Craftsmanship:

[0049] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a uniform gelatin solution. Preparation of oil phase: Melt 15g of paraffin wax at 65°C, then add 3mL of menthol and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature and allow the mixture to solidify to form microcapsules.

[0050] 3. Test results:

[0051] The fabric containing menthol microcapsules was subjected to a standard wash procedure five times (water temperature 40°C, detergent concentration according to national standards). After each wash, 10 mg of the microcapsules were added to 50 mL of release medium, and the material was shaken at a constant temperature. 1 mL of the supernatant was sampled periodically and the intensity of the characteristic absorption peak was measured using an ultraviolet spectrophotometer. The release rate of the menthol microcapsules after five washes was determined to be 80%.

[0052] Comparative Example 2-1: Single gelatin wall material

[0053] Microcapsules were prepared using gelatin alone as the wall material. 10g of gelatin was added to sufficient deionized water in a 50°C water bath and sonicated using an ultrasonic disperser to form a uniform gelatin solution. 3mL of menthol was added and stirred at 1200rpm for 15 minutes using a magnetic stirrer. The solution was then cooled to room temperature to yield the product. Under the same experimental conditions, the encapsulation efficiency was lower than the 85% achieved with the gelatin and paraffin composite wall material in Example 2. The product was also subjected to the same standard washing procedure five times, resulting in a calculated release rate of 65%.

[0054] Comparative Example 2-2: Multi-paraffin wall material

[0055] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a homogeneous gelatin solution. Preparation of the oil phase: Melt 25g of paraffin wax at 65°C, then add 3ml of menthol and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature to allow the mixture to solidify and form microcapsules.

[0056] There is too much paraffin phase and the microcapsule wall material is too thick, which affects the release of aroma substances and the release rate is slightly lower than that of Example 2.

[0057] Comparative Example 2-3: Multi-gelatin wall material

[0058] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a homogeneous gelatin solution. Preparation of the oil phase: Melt 5g of paraffin wax at 65°C, then add 3ml of menthol and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature and allow the mixture to solidify to form microcapsules.

[0059] The paraffin content is reduced, the microcapsule structure is thinner, and the aroma components are easily released, and the release rate is higher than that of Example 2. However, the wall material has insufficient protection, resulting in a low encapsulation rate.

[0060] Example 3: Jasmine Microcapsules

[0061] 1. Raw materials:

[0062] 10g gelatin, 15g paraffin (melting point 56°C), 2.5ml jasmine essential oil.

[0063] 2. Craftsmanship:

[0064] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a homogeneous gelatin solution. Preparation of the oil phase: Melt 15g of paraffin wax at 63°C, then add 2.5ml of jasmine essential oil and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature and allow the mixture to solidify to form microcapsules.

[0065] 3. Test results:

[0066] The jasmine microcapsule product was placed in a temperature cycle of 40°C during the day and 25°C at night, with each cycle repeated daily. The aroma concentration in the environment was continuously monitored. Olfactory sensory evaluation combined with electronic nose detection technology showed that the product in Example 3 could release fragrance continuously for up to 120 days.

[0067] The jasmine microcapsule product was placed in an environment with an average relative humidity of 65%. The aroma concentration was measured at regular intervals using olfactory sensory evaluation and dynamic headspace adsorption-thermal desorption-gas chromatography-mass spectrometry (DHS-TD-GC-MS). The results showed that the product was able to maintain an effective aroma concentration for six months.

[0068] Comparative Example 3-1: Single gelatin wall material

[0069] Jasmine microcapsules were prepared using gelatin alone as the wall material. In a 50°C water bath, 10 grams of gelatin was added to sufficient deionized water and ultrasonically dissolved using an ultrasonic disperser to form a uniform gelatin solution. 2.5 mL of jasmine essential oil was added, and the mixture was stirred at 1200 rpm for 15 minutes using a magnetic stirrer. The solution was then cooled to room temperature to yield the product. Under the same experimental conditions, the encapsulation efficiency was only 55%, lower than the 80% achieved with the gelatin and paraffin composite wall material in Example 3, and the aroma release rate was only 45%.

[0070] Comparative Example 3-2: Multi-paraffin wall material

[0071] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a uniform gelatin solution. Preparation of the oil phase: Melt 25g of paraffin wax at 63°C, then add 2.5mL of jasmine essential oil and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature and allow the mixture to solidify to form microcapsules.

[0072] At room temperature, the fragrance release time is up to 135 days. At 65% relative humidity, the fragrance concentration can still be maintained for 6 months, but the fragrance release rate is only 60%.

[0073] Comparative Example 3-3: Multi-gelatin wall material

[0074] Preparation of gelatin solution: In a 50°C water bath, add 10g of gelatin to sufficient deionized water and ultrasonically dissolve it using an ultrasonic disperser to form a uniform gelatin solution. Preparation of the oil phase: Melt 5g of paraffin wax at 63°C, then add 2.5mL of jasmine essential oil and ultrasonically mix using an ultrasonic disperser. Mixing and solidification: Slowly add the oil phase to the gelatin solution and stir at 1200 rpm using a magnetic stirrer for 15 minutes. Then cool to room temperature and allow the mixture to solidify to form microcapsules.

[0075] At room temperature, the fragrance release period is only about 95 days. At 65% relative humidity, the effective fragrance concentration decreases rapidly within 6 months and decreases after 3 months. The fragrance release rate is only 70%.

[0076] Embodiment 4: lemon essential oil microcapsule

[0077] 1. Raw materials:

[0078] Lemon oil, 12g, food grade gelatin, 6g, paraffin (melting point 45°C) 18g, deionized water: 94ml 2. Process:

[0079] Gelatin dissolution: Dissolve 6 g of gelatin in 94 mL of deionized water in a 50°C water bath and continue stirring until completely dissolved. Paraffin melting: Melt 18 g of paraffin at 65°C. Ultrasonic dispersion: Slowly add the melted paraffin to the gelatin aqueous solution and use an ultrasonic disperser to treat for 40 minutes. Flavor addition: Add 12 g of lemon oil to the above mixture and continue stirring for 10 minutes. Magnetic stirring: Transfer the mixture to a magnetic stirrer and stir at 45°C for 1.5 hours. Curing and drying: Transfer the mixture to a spray dryer for spray drying. The dried microcapsules are sieved to the desired particle size (100-200 μm) and then packaged and stored.

[0080] 3. Test results:

[0081] Microencapsulated fragrances begin to release fragrance when the temperature reaches 45°C. They do not release fragrance at room temperature and are not easy to break in a humid environment. They can be used for precise release of fragrance during medical hot compresses, have a wider range of storage conditions, and a long shelf life.

[0082] Comparative Example 4-1: Single gelatin wall material

[0083] Dissolve 6g of gelatin in 94ml of deionized water in a 50°C water bath, stirring continuously until completely dissolved. Add 12g of lemon oil, transfer the mixture to a magnetic stirrer, and stir at 45°C for 1.5 hours. Transfer the mixture to a spray dryer and spray dry to obtain the product. Under the same storage conditions (room temperature, 60% relative humidity, and protected from light), after four months, microcapsules made solely of gelatin exhibited a noticeable change in aroma and a weakening due to oxidation of the lemon oil. They rapidly ruptured and released at 45°C, resulting in a poorly delayed release effect.

[0084] Comparative Example 4-2: Multi-paraffin wall material

[0085] Gelatin dissolution: Dissolve 6 g of gelatin in 94 mL of deionized water in a 50°C water bath and continue stirring until completely dissolved. Paraffin melting: Melt 24 g of paraffin at 65°C. Ultrasonic dispersion: Slowly add the melted paraffin to the gelatin aqueous solution and use an ultrasonic disperser to treat it for 40 minutes. Flavor addition: Add 12 g of lemon oil to the above mixture and continue stirring for 10 minutes. Magnetic stirring: Transfer the mixture to a magnetic stirrer and stir at 45°C for 1.5 hours. Curing and drying: Transfer the mixture to a spray dryer for spray drying. The dried microcapsules are sieved to the desired particle size (100-200 μm) and then packaged and stored.

[0086] The fragrance release begins after being heated to approximately 48°C, slightly higher than the original formula. After four months, the fragrance remains stable, with a concentration close to the original. The release rate is slower, with a long-lasting fragrance release, but the initial odor perception is weak. The increased proportion of paraffin creates a denser wall material, inhibiting premature fragrance release and improving storage stability. However, the higher release temperature may affect the immediate effect in some usage scenarios.

[0087] Comparative Example 4-3: Multi-gelatin wall material

[0088] Gelatin dissolution: Dissolve 6 g of gelatin in 94 mL of deionized water in a 50°C water bath and continue stirring until completely dissolved. Paraffin melting: Melt 9 g of paraffin at 65°C. Ultrasonic dispersion: Slowly add the melted paraffin to the aqueous gelatin solution and use an ultrasonic disperser to treat for 40 minutes. Flavor addition: Add 12 g of lemon oil to the above mixture and continue stirring for 10 minutes. Magnetic stirring: Transfer the mixture to a magnetic stirrer and stir at 45°C for 1.5 hours. Curing and drying: Transfer the mixture to a spray dryer for spray drying. The dried microcapsules are sieved to the desired particle size (100-200 μm) and then packaged and stored.

[0089] It can be released when the temperature is raised to 42℃. The fragrance will become weaker after four months. The release rate will be faster but the duration will be shorter, which is suitable for short-term release scenarios.

Claims

1. A heat-responsive microcapsule fragrance, characterized in that: include: core and composite wall materials, The core material includes liquid fragrance; The composite wall material is a coating layer formed by fusing gelatin and paraffin wax through ultrasonic dispersion-magnetic stirring, wherein the mass ratio of gelatin to paraffin wax is 1:2.5 to 1:3.

75.

2. The heat-responsive microcapsule fragrance according to claim 1, characterized in that: The liquid fragrance is essential oil, and the core material loading is 10%-15% (w / w); The melting point of the paraffin wax is 45-65° C., and the surface coverage is 80%-95%.

3. The heat-responsive microcapsule fragrance according to claim 1, characterized in that: The particle size of the microcapsules is 10-200 μm.

4. A method for preparing the heat-responsive microcapsule fragrance according to any one of claims 1 to 3, characterized in that: include: 1) Dissolving a gelatin to water solution with a mass to volume ratio of 1:2.5 to 1:3 under ultrasonic conditions; 2) mixing molten paraffin wax with liquid fragrance and emulsifier to form an oil phase; 3) mixing the oil phase and gelatin solution by magnetic stirring at a speed of ≥800 rpm until the solid and liquid phases are completely fused; After cooling and solidification, solid microcapsules are separated.

5. The preparation method according to claim 4, characterized in that: In step 1), the ultrasonic dissolution conditions are power 100-200W and frequency 40kHz.

6. The preparation method according to claim 4, characterized in that: In step 2), the emulsifier is a Tween series, and the addition amount is 0.1%-0.5% of the total mass of the oil phase.

7. The preparation method according to claim 4, characterized in that: In step 3), the cooling method is water-insulated cooling, the temperature is ≤ 25° C., and the time is ≥ 5 minutes.

8. Use of the heat-responsive microcapsule fragrance according to any one of claims 1 to 3 in the field of fragrances and / or cosmetics.