A composite sustained-release skincare fragrance silicone gel and its preparation method

Abstract

This invention relates to a composite sustained-release skin-care fragrance silicone gel and its preparation method. The composite sustained-release skin-care fragrance silicone gel is composed of the following components: a silicone gel matrix, a composite sustained-release carrier, squalane, and fragrance essential oils. The composite sustained-release carrier is composed of fumed silica and β-cyclodextrin, uniformly dispersed within the silicone gel matrix. The squalane is miscible with the silicone gel matrix. The fragrance essential oils are loaded into the microporous structure of the fumed silica and the molecular cage structure of the β-cyclodextrin. The composite sustained-release skin-care fragrance silicone gel of this invention has a skin irritation index ≤0.5, and possesses excellent biocompatibility, breathability, and skin-care functions. It can be widely used in various skin adhesion products such as skin decorative patches, fragrance patches, sleep patches, mosquito repellent patches, medical dressings, and skin care patches, filling the market gap for high-quality, multifunctional fragrance silicone gel materials.

Description

Technical Field

[0001] This invention belongs to the field of polymer functional materials technology, and specifically relates to a composite sustained-release skin care fragrance silicone gel and its preparation method. Background Technology

[0002] In the fields of polymer functional materials and daily cosmetics technology, silicone gel-based skin adhesion materials are widely used in various skin adhesion products such as skin decorative patches, medical dressings, skin care patches, and scar patches due to their excellent biocompatibility, breathability, and residue-free peeling properties. The market size continues to grow rapidly. With the upgrading of consumption and the explosion of personalized demands, fragrance-enhancing silicone gel materials that combine adhesive function with olfactory experience are gradually becoming an emerging hot spot in the industry, giving products a unique sensory experience and significantly increasing their added value.

[0003] However, current technologies for preparing fragrance silicone gel materials still suffer from numerous insurmountable core defects, failing to meet the high-quality requirements of industrial applications. Firstly, the poor compatibility between fragrance essential oils and silicone gel systems, with direct addition severely interfering with the cross-linking and curing reaction of the silicone gel, is a major issue. Fragrance essential oils are mostly small-molecule volatile organic compounds, which can disrupt the hydrogen bond network and cross-linking sites of the A and B component addition-type silicone gel. This leads to incomplete curing, decreased mechanical properties, unstable adhesion, and even complete failure to cure, representing a key technological bottleneck restricting the large-scale production of fragrance silicone gel materials. Existing technologies often force a significant reduction in the amount of essential oil added to achieve curing, resulting in insufficient fragrance concentration and an inability to achieve the desired olfactory effect.

[0004] Secondly, the lack of dedicated fragrance slow-release carriers and controlled-release structures results in extremely rapid and uneven fragrance release: even if a small amount of essential oil can be successfully mixed into the silicone gel system, the lack of effective adsorption and encapsulation causes the essential oil to evaporate quickly within a short time, with an effective fragrance duration typically less than 2 hours, failing to achieve a long-lasting fragrance experience. Furthermore, directly mixed essential oils accumulate on the surface of the silicone gel, not only accelerating evaporation but also potentially causing skin irritation due to excessively high local concentrations, posing a safety risk, especially for people with sensitive skin.

[0005] Furthermore, existing fragrance silicone gel materials generally do not consider the integration of skincare functions, failing to nourish the skin while providing adhesion and fragrance. They also lack differentiated controlled-release designs for the top, middle, and base notes of the fragrance, resulting in a one-dimensional fragrance experience. Although some studies have attempted to use porous materials to adsorb essential oils before mixing them into silicone gels, these often use a single carrier, failing to simultaneously address the dual problems of curing interference and long-lasting sustained release. They also cannot achieve layered and orderly release of fragrance, thus failing to overcome the core limitations of current technology.

[0006] Therefore, there is an urgent need in this field to develop a novel fragrance silicone gel material that can simultaneously solve the problems of essential oil interference and curing, as well as the problem of excessively rapid fragrance release, and also has skin care benefits and fragrance layered release function, in order to fill the current market gap and promote the widespread application of fragrance silicone gel materials in various skin adhesion products. Summary of the Invention

[0007] The purpose of this invention is to provide a composite sustained-release skincare fragrance silicone gel and its preparation method, which solves the core technical problems in the prior art where the direct addition of fragrance essential oils leads to incomplete solidification of the silicone gel and excessively fast and uneven fragrance release. At the same time, it endows the silicone gel material with skincare functions, achieving a balance between long-lasting and uniform fragrance release and excellent skin compatibility.

[0008] This invention provides a composite sustained-release skincare fragrance silicone gel, which is composed of the following components: a silicone gel matrix, a composite sustained-release carrier, squalane, and fragrance essential oils; the composite sustained-release carrier is composed of fumed silica and β-cyclodextrin, uniformly dispersed within the silicone gel matrix; the squalane is miscible with the silicone gel matrix; and the fragrance essential oils are respectively loaded into the microporous structure of fumed silica and the molecular cage structure of β-cyclodextrin.

[0009] Preferably, the silicone gel matrix is ​​a two-component addition-type silicone gel with a mass ratio of 1:1 (component A is vinyl-terminated polydimethylsiloxane, and component B is hydrogen-containing polysiloxane).

[0010] Preferably, the mass ratio of fumed silica to fragrance oil in the composite sustained-release carrier is 1:10 to 1:30, and the mass ratio of β-cyclodextrin to fragrance oil is 3:1 to 10:1.

[0011] Preferably, the amount of squalane added is 1%-3% of the total mass of the silicone gel matrix, and more preferably 1%.

[0012] Preferably, the total amount of the fragrance essential oil added is 2%-5% of the total mass of the silicone gel matrix, more preferably 3%, wherein the top note essential oil accounts for 40%-60%, the middle note essential oil accounts for 25%-35%, and the base note essential oil accounts for 10%-25%. Preferably, sweet orange essential oil, rose essential oil, and sandalwood essential oil are blended in a mass ratio of 1:1:1.

[0013] Preferably, the thickness of the composite slow-release skin fragrance silicone gel after curing is 100μm-3mm, and more preferably 2mm.

[0014] Preferably, the skin irritation index of the composite sustained-release skin fragrance silicone gel is ≤0.5, which meets the non-irritating standard of GB / T16886.10-2017.

[0015] This invention also provides a method for preparing a composite sustained-release skincare fragrance silicone gel, comprising the following steps:

[0016] (1) Mix the top notes, middle notes and base notes in proportion and stir for 10-20 minutes until uniform to obtain a compound fragrance essential oil premix.

[0017] (2) Add fumed silica to the above-mentioned compound fragrance essential oil premix and stir for 10-30 min until the fumed silica fully adsorbs the fragrance essential oil through the microporous structure to form a fumed silica-fragrance essential oil dispersion.

[0018] (3) Continue to add β-cyclodextrin to the above dispersion and stir for 10-30 min until β-cyclodextrin completely encapsulates the fragrance essential oil molecules through molecular inclusion to form a complex fragrance premix;

[0019] (4) Add the above-mentioned composite fragrance premix to the silicone gel matrix and stir for 10-40 minutes until the system is completely homogeneous;

[0020] (5) Add squalane and continue stirring for 10-30 minutes until completely miscible to obtain a mixture;

[0021] (6) The mixture is subjected to vacuum degassing treatment, and the degassed mixture is coated on the surface of the substrate and cured to obtain the composite slow-release skin care fragrance silicone gel.

[0022] Preferably, the vacuum degassing time in step (5) is 10-30 min.

[0023] Preferably, the substrate in step (6) is selected from one of PU film, silicone film, PET release film, non-woven fabric, and woven fabric.

[0024] Preferably, the coating method in step (6) is one of slot coating, blade coating, or roller coating. Slot coating is preferred, and the coating speed is 2-10 m / min.

[0025] Preferably, the curing process in step (6) adopts a segmented heating method, first pre-curing at 40-60℃ for 10-20 minutes, and then fully curing at 80-120℃ for 5-15 minutes.

[0026] The present invention also provides a skin-adhesive product comprising the aforementioned composite sustained-release skin-care fragrance silicone gel.

[0027] Preferably, the skin-adhesive product is selected from one of the following: skin decorative patches, fragrance patches, sleep patches, mosquito repellent patches, medical dressings, skin care patches, and scar patches.

[0028] Beneficial effects

[0029] This invention fundamentally solves the industry problem of direct addition of fragrance essential oils interfering with the cross-linking and curing reaction of silicone gel by employing an innovative process of "pre-mixing essential oils - step-by-step loading - finally adding silicone gel matrix," thus improving the ability to achieve complete curing even with a large amount of total essential oil added. Simultaneously, this invention utilizes a composite sustained-release carrier system of fumed silica and β-cyclodextrin, leveraging the different mechanisms of action of the two carriers to achieve layered and orderly release of fragrance, resulting in an effective fragrance retention time of over 72 hours, far superior to existing technologies. Furthermore, by adding squalane, this invention endows the silicone gel material with excellent skincare functions, further enhancing the user experience. The preparation process of this invention is simple and controllable, suitable for roll-to-roll mass production. The prepared silicone gel material exhibits good biocompatibility and breathability, and can be widely used in various skin-adhesive products such as skin decorative patches, medical dressings, skincare patches, and fragrance patches, possessing broad market prospects and commercial value. Attached Figure Description

[0030] Figure 1 Digital photographs of three fragrance silicone gel samples: (a) fragrance silicone gel without sustained-release carrier; (b) fragrance silicone gel with single carrier; and (c) composite sustained-release skincare fragrance silicone gel.

[0031] Figure 2 The fragrance sustained-release performance curves of three fragrance silicone gel samples are shown.

[0032] Figure 3 A comparison of the adhesion properties of three fragrance silicone gel samples. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] In one aspect, the present invention provides a composite sustained-release skincare fragrance silicone gel, which is composed of the following components: a silicone gel matrix, a composite sustained-release carrier, squalane, and fragrance essential oils; the composite sustained-release carrier is composed of fumed silica and β-cyclodextrin, uniformly dispersed within the silicone gel matrix; the squalane is miscible with the silicone gel matrix; and the fragrance essential oils are respectively loaded in the microporous structure of fumed silica and the molecular cage structure of β-cyclodextrin.

[0035] In some embodiments, the silicone gel matrix is ​​a two-component addition-type silicone gel with a mass ratio of 1:1 (component A is vinyl-terminated polydimethylsiloxane, and component B is hydrogen-containing polysiloxane), with a curing temperature of 25-120℃ and a curing time of 5-60 min. Preferably, a staged temperature-curing method is used: first, pre-curing at 40-60℃ for 10-20 min, and then fully curing at 80-120℃ for 5-15 min. This curing method can effectively avoid internal stress caused by rapid curing, ensuring the stability of the mechanical and adhesive properties of the silicone gel.

[0036] In some embodiments, the mass ratio of fumed silica to essential oil in the composite sustained-release carrier is 1:10 to 1:30, and the mass ratio of β-cyclodextrin to essential oil is 3:1 to 10:1. Preferably, the mass ratio of fumed silica to essential oil in the composite sustained-release carrier is 1:20, and the mass ratio of β-cyclodextrin to essential oil is 8:1. Fumed silica has a rich microporous structure, which adsorbs highly volatile essential oil components through physical adsorption; β-cyclodextrin has a hollow cage-like structure, which encapsulates less volatile essential oil components through molecular inclusion. The synergistic effect of the two can achieve the layered and orderly release of fragrance, effectively prolonging the fragrance duration.

[0037] In some embodiments, the total amount of the fragrance essential oil added is 2%-5% of the total mass of the silicone gel matrix, preferably 3%. The fragrance essential oil can be blended from top note, middle note, and base note essential oils in any proportion, preferably a blend of sweet orange essential oil (top note), rose essential oil (middle note), and sandalwood essential oil (base note) in a 1:1:1 mass ratio. This ratio creates a rich, naturally harmonious fragrance experience.

[0038] In some embodiments, the amount of squalane added is 0.1%-3% of the total mass of the silicone gel matrix, preferably 1%. Squalane is similar in composition to human sebum, has good skin affinity, and can be slowly released when the silicone gel is applied to the skin, nourishing the skin, improving skin feel, and enhancing the user experience.

[0039] In some embodiments, the cured silicone gel has a thickness of 100 μm to 3 mm, preferably 2 mm. This thickness range ensures good flexibility and skin adhesion of the silicone gel while avoiding the foreign body sensation caused by excessive thickness. The skin irritation index of the silicone gel is ≤0.5, which meets the non-irritating standard of GB / T 16886.10-2017.

[0040] In another aspect, the present invention provides a method for preparing the above-mentioned composite sustained-release skincare fragrance silicone gel, comprising the following steps:

[0041] (1) Mix the top notes, middle notes and base notes in proportion and stir for 10-20 minutes until uniform to obtain a compound fragrance essential oil premix.

[0042] (2) Add fumed silica to the above-mentioned compound fragrance essential oil premix and stir for 10-30 min until the fumed silica fully adsorbs the fragrance essential oil through the microporous structure to form a fumed silica-fragrance essential oil dispersion.

[0043] (3) Continue to add β-cyclodextrin to the above dispersion and stir for 10-30 min until β-cyclodextrin completely encapsulates the fragrance essential oil molecules through molecular inclusion to form a complex fragrance premix;

[0044] (4) Add the above-mentioned composite fragrance premix to the silicone gel matrix and stir for 10-40 minutes until the system is completely homogeneous;

[0045] (5) Add squalane and continue stirring for 10-30 minutes until completely miscible to obtain a mixture;

[0046] (6) The mixture is subjected to vacuum degassing treatment, and the degassed mixture is coated on the surface of the substrate and cured to obtain the composite slow-release skin care fragrance silicone gel.

[0047] In some implementations, the coating method in step (6) is slot coating, blade coating, or roller coating, preferably slot coating, with a coating speed of 2-10 m / min. This allows for precise control of the coating thickness, ensuring uniform product quality and suitability for roll-to-roll mass production. The substrate can be any material suitable for supporting silicone gel, such as release film, nonwoven fabric, or woven fabric.

[0048] Comparative Example 1 (Fragrance Silicone Gel Without Sustained-Release Carrier)

[0049] Mix the two-component addition-type silicone gels A and B at a mass ratio of 1:1 and stir until homogeneous to obtain a silicone gel matrix. Directly add 3% by mass of a compound fragrance essential oil (sweet orange essential oil: rose essential oil: sandalwood essential oil = 1:1:1) and continue stirring for 20 minutes until homogeneous. Perform vacuum degassing treatment on the mixture for 15 minutes. Pour the degassed mixture into a mold and cure it using the same segmented heating method as in Example 1: first pre-curing at 50℃ for 15 minutes, and then fully curing at 90℃ for 10 minutes to obtain a carrier-free fragrance silicone gel sample with a thickness of 2 mm.

[0050] Comparative Example 2 (Single-Carrier Fragrance Silicone Gel)

[0051] Mix the two-component addition-type silica gels A and B at a mass ratio of 1:1 and stir until homogeneous to obtain the silica gel matrix.

[0052] Step 1: Premixed Fragrance Essential Oils: Mix 1% by weight of sweet orange essential oil (top note), 1% by weight of rose essential oil (middle note) and 1% by weight of sandalwood essential oil (base note), stir for 10 minutes until uniform, and obtain a compound fragrance essential oil premix liquid with a total mass fraction of 3%.

[0053] Step 2: Adsorption of fumed silica: Add 0.15% by mass of fumed silica (the mass ratio of fumed silica to total essential oil is 1:20) to the above-mentioned compound fragrance essential oil premix and stir for 20 minutes until the fumed silica fully adsorbs the essential oil through the microporous structure to form a fumed silica-essential oil dispersion.

[0054] Step 3: Slowly add the above fumed silica-essential oil dispersion to the silica gel matrix and continue stirring for 30 minutes until the system is completely homogeneous; perform vacuum degassing treatment on the mixture for 15 minutes; pour the degassed mixture into a mold and cure it using the same segmented heating method as in Example 1: first pre-curing at 50℃ for 15 minutes, and then completely curing at 90℃ for 10 minutes to obtain a single-carrier fragrance silica gel sample with a thickness of 2 mm.

[0055] Example 1 (Compound sustained-release skincare fragrance silicone gel)

[0056] Mix the two-component addition-type silica gels A and B at a mass ratio of 1:1 and stir until homogeneous to obtain the silica gel matrix.

[0057] Step 1: Premixed Fragrance Essential Oils: Mix 1% by weight of sweet orange essential oil (top note), 1% by weight of rose essential oil (middle note) and 1% by weight of sandalwood essential oil (base note), stir for 10 minutes until uniform, and obtain a compound fragrance essential oil premix liquid with a total mass fraction of 3%.

[0058] Step 2: Adsorption of fumed silica: Add 0.15% by mass of fumed silica (the mass ratio of fumed silica to total essential oil is 1:20) to the above-mentioned compound fragrance essential oil premix and stir for 20 minutes until the fumed silica fully adsorbs the essential oil through the microporous structure to form a fumed silica-essential oil dispersion.

[0059] Step 3: β-Cyclodextrin inclusion: Continue to add 0.625% by mass of β-cyclodextrin (β-cyclodextrin to total essential oil mass ratio of 8:1) to the above dispersion, and stir for 25 minutes until β-cyclodextrin completely encapsulates the essential oil molecules through molecular inclusion to form a complex fragrance premix.

[0060] Step 4: Slowly add the composite fragrance premix to the silicone gel matrix and stir for 30 minutes until the system is completely homogeneous; then add 1% by mass of squalane and continue stirring for 15 minutes until completely miscible; perform vacuum degassing treatment on the mixture for 15 minutes; pour the degassed mixture into a mold and cure it using a segmented heating method: first pre-curing at 50℃ for 15 minutes, and then completely curing at 90℃ for 10 minutes to obtain a composite slow-release skin fragrance silicone gel sample with a thickness of 2 mm.

[0061] Performance testing and results analysis:

[0062] (1) Appearance and curing properties

[0063] The appearance of the silica gel samples prepared in Comparative Example 1, Comparative Example 2, and Example 1 was observed respectively, and the results are as follows: Figure 1 As shown. Figure 1 a is a carrier-free fragrance silicone gel sample. Direct addition of essential oils resulted in poor system compatibility, a slight decrease in transparency, and a slight whitening at the edges. Figure 1 b is a single-carrier fragrance silicone gel sample. After adding fumed silica, the system compatibility was significantly improved, the transparency was increased, and there were no bubbles or clumps. Figure 1 Sample c is a composite slow-release skincare fragrance silicone gel sample. It is highly transparent, free of impurities, has a smooth and flat surface, and is completely cured without any essential oil migration or phase separation. This result demonstrates that the composite carrier system of this invention effectively solves the problem of poor compatibility between essential oils and the silicone gel matrix. Even with a total essential oil content of 3%, it can still achieve complete curing, fully meeting the appearance requirements of skin-adhesive products.

[0064] (2) Fragrance sustained-release performance

[0065] Under conditions of 25℃ and 50% relative humidity, the fragrance release performance of three samples was continuously monitored for 72 hours using an electronic nose. The odor value change curve over time is shown below. Figure 2 As shown in the figure, the carrier-free fragrance silicone gel sample exhibits extremely rapid fragrance release, with an odor value of only 125 after 72 hours and an effective fragrance retention time of less than 24 hours. In the single-carrier fragrance silicone gel sample, the microporous adsorption of fumed silica significantly delays essential oil evaporation, with an odor value of 180 after 72 hours and an effective fragrance retention time extended to 48 hours. The composite sustained-release skincare fragrance silicone gel sample achieves layered controlled release of fragrance through the synergistic effect of fumed silica and β-cyclodextrin, maintaining an odor value of around 410 after 72 hours and an effective fragrance retention time of over 72 hours, far superior to the control group and the single-carrier group. These results fully demonstrate the superiority of the composite sustained-release system of this invention, enabling sustained and uniform fragrance release.

[0066] (3) Holding power

[0067] According to the method for determining the holding power of adhesive tape specified in national standard GB / T 4581-2014, the holding time of three samples against a standard steel plate was determined under the conditions of a constant weight of 500g, a temperature of (23±1)℃, and a relative humidity of (50±5)%. The results are as follows: Figure 3 As shown, the hold time of the carrier-free fragrance silicone gel sample was approximately 21 minutes, indicating poor adhesion and easy detachment from the skin surface; the hold time of the single-carrier fragrance silicone gel sample was approximately 25 minutes, showing improved adhesion; and the hold time of the composite sustained-release skin fragrance silicone gel sample was approximately 22 minutes, maintaining good adhesive stability and leaving no adhesive residue upon removal. These results demonstrate that the composite sustained-release system of this invention significantly improves the fragrance sustained-release effect without adversely affecting the adhesive properties of the silicone gel, thus balancing stability and skin-friendliness.

[0068] The foregoing description merely illustrates exemplary embodiments of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of this application.

Claims

1. A composite sustained-release skincare fragrance silicone gel, characterized in that, The composite sustained-release skincare fragrance silicone gel is composed of the following components: a silicone gel matrix, a composite sustained-release carrier, squalane, and fragrance essential oils; the composite sustained-release carrier is composed of fumed silica and β-cyclodextrin, which are uniformly dispersed inside the silicone gel matrix; the squalane is miscible with the silicone gel matrix; and the fragrance essential oils are respectively loaded in the microporous structure of fumed silica and the molecular cage structure of β-cyclodextrin.

2. The composite sustained-release skincare fragrance silicone gel according to claim 1, characterized in that, The mass ratio of fumed silica to essential oil in the composite sustained-release carrier is 1:10 to 1:30, and the mass ratio of β-cyclodextrin to essential oil is 3:1 to 10:

1.

3. The composite sustained-release skincare fragrance silicone gel according to claim 1, characterized in that, The amount of squalane added is 1%-3% of the total mass of the silicone gel matrix.

4. The composite sustained-release skincare fragrance silicone gel according to claim 1, characterized in that, The total amount of the fragrance essential oil added is 2%-5% of the total mass of the silicone gel matrix, of which the top note essential oil accounts for 40%-60%, the middle note essential oil accounts for 25%-35%, and the base note essential oil accounts for 10%-25%.

5. A method for preparing a composite sustained-release skincare fragrance silicone gel as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Mix the top notes, middle notes and base notes in proportion and stir for 10-20 minutes until uniform to obtain a compound fragrance essential oil premix. (2) Add fumed silica to the above-mentioned compound fragrance essential oil premix and stir for 10-30 min until the fumed silica fully adsorbs the fragrance essential oil through the microporous structure to form a fumed silica-fragrance essential oil dispersion. (3) Continue to add β-cyclodextrin to the above dispersion and stir for 10-30 min until β-cyclodextrin completely encapsulates the fragrance essential oil molecules through molecular inclusion to form a complex fragrance premix; (4) Add the above-mentioned composite fragrance premix to the silicone gel matrix and stir for 10-40 minutes until the system is completely homogeneous; (5) Add squalane and continue stirring for 10-30 minutes until completely miscible to obtain a mixture; (6) The mixture is subjected to vacuum degassing treatment, and the degassed mixture is coated on the surface of the substrate and cured to obtain the composite slow-release skin care fragrance silicone gel.

6. The preparation method according to claim 5, characterized in that, The vacuum degassing time in step (5) is 10-30 min.

7. The preparation method according to claim 5, characterized in that, The coating method in step (6) is one of slot coating, scraping, or roller coating.

8. The preparation method according to claim 5, characterized in that, The curing process in step (6) adopts a segmented heating method, first pre-curing at 40-60℃ for 10-20 minutes, and then fully curing at 80-120℃ for 5-15 minutes.

9. A skin-adhesive product, characterized in that, It contains a composite sustained-release skincare fragrance silicone gel as described in any one of claims 1-4.

10. The skin-adhesive article according to claim 9, characterized in that, The skin-adhesive product is selected from one of the following: decorative skin patches, fragrance patches, sleep patches, mosquito repellent patches, medical dressings, skin care patches, and scar patches.

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