Napkin dipping process with fragrance slow-release function

Abstract

The invention belongs to the technical field of daily necessity processing, and provides a napkin dipping process with a fragrance slow-release function, which comprises the following steps: S1, dissolving gelatin and Arabic gum in water at 50-60 DEG C according to a ratio of 1: 1 to form a wall material liquid, adding perfume, emulsifying at a high speed to obtain an emulsion, regulating the temperature and the pH to promote coagulation, curing by glutaraldehyde, and centrifugally freeze-drying to obtain microcapsule powder; s2, dispersing 5-10 wt% of the microcapsule powder in water-based acrylic resin, and adding 2-5 wt% of cyclodextrin and 1-3 wt% of nano silicon dioxide to prepare an impregnation liquid; s3, the napkin is sequentially subjected to pre-impregnation, vacuum impregnation and hot air curing, so that functional components in impregnation liquid are fixed to the surfaces and the interiors of paper fibers; s4, triggering the microcapsule to break through a friction effect to release 70-80% of main fragrance, and continuously releasing residual fragrance through cyclodextrin and nano silicon dioxide; through the synergistic effect of the core-shell structure microcapsules, the cyclodextrin and the nano silicon dioxide, the controlled release of fragrance is realized, and meanwhile, the use performance of the napkin is ensured.

Description

Technical Field

[0001] This invention belongs to the field of daily necessities processing technology, specifically a napkin impregnation process with a slow-release fragrance function. Background Technology

[0002] As consumers increasingly demand more diverse functions in daily necessities, scented napkins, offering a pleasant sensory experience during cleaning, are gradually becoming one of the mainstream products in the market. Currently, the industry's manufacturing technology for scented napkins mainly relies on traditional impregnation processes, but these processes have significant shortcomings in terms of fragrance release control, load uniformity, storage stability, and substrate performance maintenance.

[0003] Current technologies mostly employ a simple impregnation method, directly dissolving or dispersing fragrances in adhesives, lacking an effective slow-release control mechanism. In this type of process, fragrance molecules are directly exposed to the environment, easily losing their scent rapidly due to volatilization and diffusion. This results in an initially overly strong and pungent aroma that quickly dissipates and becomes odorless, typically lasting only 1-3 days, failing to meet consumers' demand for a sustained fragrance experience. Some technologies attempt to introduce single microcapsules to encapsulate the fragrance, but due to the lack of a secondary slow-release carrier, the fragrance is quickly released after the microcapsules rupture, still making it difficult to achieve a balance between instant burst and long-lasting fragrance.

[0004] Furthermore, due to the loose and porous structure of napkin fibers, simple soaking or spraying processes can easily cause fragrance to accumulate on the fiber surface, forming localized areas with excessively strong odors, while the internal fibers are not adequately loaded, affecting the overall user experience. At the same time, fragrances or microcapsules that have not undergone stabilization treatment are prone to degradation during storage due to temperature changes and oxidation, leading to the loss of fragrance components. After storage at 40℃ for 3 months, the fragrance retention rate is typically below 60%, severely impacting the product's shelf life and quality.

[0005] Meanwhile, existing technologies often use excessive amounts of water-based resins and other adhesives, or employ high-temperature, long-term curing processes, to enhance fragrance adhesion. This damages the bonding between napkin fibers, reduces softness, and significantly lowers tensile and wet tensile strength. As a result, napkins are prone to shedding and tearing during daily wiping, sacrificing their core functionality. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a napkin impregnation process with a sustained-release fragrance function. Through the synergistic effect of core-shell microcapsules, cyclodextrin, and nano-silica, the fragrance is released in a controlled manner while ensuring the napkin's performance, thus solving the problems mentioned in the background art.

[0007] A napkin impregnation process with slow-release fragrance includes the following steps:

[0008] S1. Dissolve gelatin and gum arabic in deionized water at 50-60℃ in a 1:1 mass ratio to form a wall material solution. Add oil-soluble fragrance and emulsify at high speed to form an O / W type emulsion. Cool to 40℃ and adjust pH to 4.5-5.5 to trigger composite coagulation. Add 0.5-1.0% glutaraldehyde to crosslink and solidify the capsule wall. After centrifugation, freeze dry to obtain microcapsule powder.

[0009] S2. Disperse the microcapsule powder obtained in step S1 at 5-10 wt% in an aqueous acrylic resin with a solid content of 20-30%, then add 2-5 wt% cyclodextrin and 1-3 wt% nano silica, and stir until uniform.

[0010] S3. The napkins are sequentially pre-impregnated, vacuum impregnated, and hot-air cured to fix the functional components in the impregnation solution onto the surface and interior of the paper fibers.

[0011] S4. The microcapsules are ruptured by friction to release 70-80% of the main fragrance. The remaining fragrance is continuously released through the adsorption-desorption balance of cyclodextrin and nano-silica, with a total sustained-release period of ≥7 days.

[0012] Preferably, the oil-soluble fragrance in step S1 is at least one of limonene and citronellol, and the particle size distribution of the microcapsule powder is 5-20 μm.

[0013] Preferably, the aqueous acrylic resin in step S2 is a core-shell emulsion with a glass transition temperature of 0-10°C, and the emulsion contains 0.1-0.5 wt% of a silane coupling agent.

[0014] Preferably, in step S2, the cyclodextrin is β-cyclodextrin or hydroxypropyl-β-cyclodextrin, and its molar inclusion ratio with the flavoring is 1:1-2:1.

[0015] Preferably, in step S2, the particle size of the nano-silica is 20-50 nm, and its surface is modified with KH-550 silane coupling agent, with a hydroxyl coverage of ≥30%.

[0016] Preferably, the pre-impregnation operation in step S3 involves immersing the sample in an impregnation solution at 50°C for 30 seconds, assisted by 100-200W ultrasound; the frequency of the ultrasound-assisted impregnation is 20-40kHz, and the power density is 0.5-1.0W / cm³. 2 Furthermore, the pre-impregnation process employs reciprocating stirring at a speed of 30-50 rpm.

[0017] Preferably, in step S3, the vacuum degree of vacuum impregnation is adjusted within the range of -0.06 to -0.09 MPa, and 2-3 pressure cycles are performed during the impregnation process. The pressure cycle involves going from atmospheric pressure to the set vacuum degree and then back to atmospheric pressure.

[0018] Preferably, in step S3, hot air curing is performed by drying at 80-100°C for 5-10 minutes.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention constructs a dual release mechanism through the synergistic effect of core-shell structured microcapsules and composite carriers: the microcapsules release 70-80% of the fragrance instantaneously under friction, creating an immediate sense of pleasure; the molecular inclusion effect of cyclodextrin and the physical adsorption effect of nano-silica achieve the slow desorption of the remaining fragrance.

[0021] 2. This invention employs a process combining ultrasonic-assisted pre-impregnation and vacuum pressure cyclic impregnation to ensure that functional components such as microcapsules and cyclodextrin are evenly distributed on the surface and internal pores of paper fibers, avoiding the off-flavor problem caused by localized fragrance aggregation in traditional processes. At the same time, the microcapsule wall material, which is cross-linked and cured with glutaraldehyde, forms a dense protective structure with high fragrance retention, significantly improving the shelf-life stability of the product.

[0022] 3. By optimizing the amount of water-based acrylic resin and the curing process, this invention achieves fragrance functionality while minimizing the impact on the physical properties of paper, thus meeting the strength requirements for daily wiping. Attached Figure Description

[0023] Figure 1 This is a flowchart of the process for impregnating napkins with a slow-release fragrance function according to the present invention. Detailed Implementation

[0024] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0025] As attached Figure 1 As shown:

[0026] Example 1:

[0027] 1. Microcapsule preparation:

[0028] Wall material solution: Dissolve 5g of gelatin and 5g of gum arabic in 180g of 55℃ deionized water and stir until completely dissolved;

[0029] Fragrance emulsion: Add 30g limonene (oil phase) and emulsify at 12000rpm for 8 minutes to form an O / W emulsion with an oil phase particle size of about 15μm;

[0030] Coagulation and curing: Cool to 40°C, adjust pH to 5.0 with 10% acetic acid, stir for 30 minutes; add 1g glutaraldehyde (0.5% relative to the total mass of the wall material), crosslink at 40°C for 60 minutes;

[0031] Post-processing: After centrifugation, freeze-drying was performed to obtain limonene microcapsule powder with a particle size of 8-18 μm.

[0032] 2. Preparation of impregnation solution:

[0033] Ingredients: 8g microcapsule powder, 65g water-based acrylic resin (25% solid content), 3g β-cyclodextrin, 2g nano silica (20-50nm, KH-550 modified), 22g deionized water;

[0034] Preparation: The microcapsules were dispersed in acrylic resin and ultrasonically dispersed at 300W for 10 minutes; cyclodextrin and nano-silica were added and stirred at 300rpm for 20 minutes.

[0035] 3. Three-stage impregnation:

[0036] Pre-impregnation: Napkins (35g / m²) 2 Immerse in 50℃ impregnation solution for 30 seconds, ultrasonically treat with 30kHz, 150W, and stir repeatedly at 40rpm.

[0037] Vacuum impregnation: Treat with a vacuum of -0.08MPa for 10 minutes, followed by two pressure cycles;

[0038] Hot air curing: Dry at 90℃ for 8 minutes.

[0039] 4. Performance Testing:

[0040] Fragrance release: The initial fragrance intensity (out of 10) after friction was 8.5 points, and it was 3.5 points on the 7th day, with a total sustained-release period of 10 days;

[0041] Stability: After 3 months of storage at 40℃, the flavor retention rate is 88%;

[0042] Physical properties: Tensile index 4.2 N·m / g, wet tensile index 1.2 N·m / g, a decrease of 8% compared to untreated paper.

[0043] Example 2:

[0044] 1. Microcapsule preparation:

[0045] Wall material solution: Dissolve 4g of gelatin and 4g of gum arabic in 150g of deionized water at 60℃;

[0046] Fragrance emulsion: Add 20g citronellol, emulsify at 15000rpm for 5 minutes, oil phase particle size is about 10μm;

[0047] Coagulation and curing: Adjust the pH to 4.5, add 0.8g glutaraldehyde (1.0% relative to the total mass of the wall material), and crosslink at 40℃ for 60 minutes;

[0048] Post-processing: After freeze-drying, citronellol microcapsule powder with a particle size of 5-15 μm is obtained.

[0049] 2. Preparation of impregnation solution:

[0050] Ingredients: 5g microcapsule powder, 60g water-based acrylic resin (30% solid content), 5g hydroxypropyl-β-cyclodextrin, 3g nano silica, 27g deionized water;

[0051] Preparation: Same as in Example 1.

[0052] 3. Three-stage impregnation:

[0053] Pre-impregnation: 50℃, 40kHz, 200W ultrasonic wave, 50rpm stirring;

[0054] Vacuum impregnation: -0.09MPa, 3 pressure cycles;

[0055] Hot air curing: Dry at 100℃ for 5 minutes.

[0056] 4. Performance Testing:

[0057] Fragrance release: initial strength 8.2 points, day 7 strength 3.2 points, sustained release period 9 days;

[0058] Stability: After 3 months of storage at 40℃, the flavor retention rate is 86%;

[0059] Physical properties: tensile index 4.0 N·m / g, wet tensile index 1.1 N·m / g, a decrease of 9%.

[0060] Comparative example: The impregnation process using existing technology that directly adds fragrance is employed, and the specific steps are as follows:

[0061] Preparation of impregnation solution: Disperse 5 wt% oil-soluble fragrance (limonene) directly in 65 wt% water-based acrylic resin (solid content 25%), add deionized water to make up the balance, and stir evenly;

[0062] Impregnation treatment: Impregnate the napkin (35g / m²) with water. 2 Soak in 50℃ impregnation solution for 60 seconds, drain naturally, and then dry in 80℃ hot air for 10 minutes;

[0063] Performance characteristics: Without microcapsule encapsulation and the synergistic effect of composite carriers, the fragrance is directly exposed to the environment and is simply fixed by resin film formation.

[0064] The parameter and performance comparison results are shown in the table below:

[0065]

[0066]

[0067] As shown above, this technology utilizes a dual mechanism of "instantaneous release from core-shell microcapsules + sustained release from cyclodextrin / nano silica," achieving a sustained release period of 9-10 days, which is more than three times longer than the traditional process (3 days). Even on the 7th day, the aroma intensity of Example 1 remains at 3.5 points, while the traditional process has virtually no aroma residue. This solves the defect of traditional products being "too strong initially and tasteless later," significantly improving the aroma sustained release performance.

[0068] The microcapsule wall material cross-linked with glutaraldehyde forms a dense protective structure, and after storage at 40°C for 3 months, the fragrance retention rate reaches 86-88%, which is much higher than the 52% of the traditional process. This is due to the physical barrier effect of the microcapsules on the fragrance, which effectively inhibits the volatilization and oxidative degradation of the fragrance and greatly enhances the stability of the fragrance.

[0069] Ultrasonic-assisted penetration effectively promotes rapid diffusion of the impregnation solution, while vacuum pressure circulation removes air from fiber pores, enhancing liquid-solid contact. This combined process ensures that functional components such as microcapsules and cyclodextrins are evenly distributed on and within the paper fibers. Compared to the localized aggregation problems of traditional processes, this technology results in napkins with a more even fragrance release and no irritating odors during use.

[0070] Optimized waterborne acrylic resin dosage (60-65 wt%) and curing conditions (short-time drying at 80-100℃) ensured the fixation of functional components while avoiding excessive paper hardening or strength loss. The tensile strength of the example decreased by only 8-9%, with a wet tensile index ≥1.1 N·m / g, meeting the strength requirements for daily wiping of napkins; while traditional processes, due to fragrances directly damaging fiber bonding, resulted in a strength decrease of up to 15%, failing to maintain good physical properties.

[0071] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible without substantially departing from the novel teachings and advantages of the subject matter described in this application. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the invention is not limited to the particular embodiments but extends to a variety of modifications that still fall within the scope of the appended claims.

[0072] It should be understood that numerous specific implementation decisions can be made during the development of any actual implementation method, and in any engineering or design project. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0073] It should be noted that 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A napkin impregnation process with a slow-release fragrance function, characterized in that, Includes the following steps: S1. Dissolve gelatin and gum arabic in deionized water at 50-60℃ in a 1:1 mass ratio to form a wall material solution. Add oil-soluble fragrance and emulsify at high speed to form an O / W type emulsion. Cool to 40℃ and adjust pH to 4.5-5.5 to trigger composite coagulation. Add 0.5-1.0% glutaraldehyde to crosslink and solidify the capsule wall. After centrifugation, freeze dry to obtain microcapsule powder. S2. Disperse the microcapsule powder obtained in step S1 at 5-10 wt% in an aqueous acrylic resin with a solid content of 20-30%, then add 2-5 wt% cyclodextrin and 1-3 wt% nano silica, and stir until uniform. S3. The napkins are sequentially pre-impregnated, vacuum impregnated, and hot-air cured to fix the functional components in the impregnation solution onto the surface and interior of the paper fibers. S4. The microcapsules are ruptured by friction to release 70-80% of the main fragrance. The remaining fragrance is continuously released through the adsorption-desorption balance of cyclodextrin and nano-silica, with a total sustained-release period of ≥7 days.

2. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S1, the oil-soluble fragrance is at least one of limonene and citronellol, and the particle size distribution of the microcapsule powder is 5-20 μm.

3. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S2, the aqueous acrylic resin is a core-shell emulsion with a glass transition temperature of 0-10°C, and the emulsion contains 0.1-0.5 wt% of a silane coupling agent.

4. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S2, the cyclodextrin is β-cyclodextrin or hydroxypropyl-β-cyclodextrin, and its molar inclusion ratio with the flavoring is 1:1-2:

1.

5. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S2, the particle size of the nano-silica is 20-50 nm, and its surface is modified with KH-550 silane coupling agent, with a hydroxyl coverage of ≥30%.

6. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S3, the pre-impregnation operation involves immersing the sample in a 50°C impregnation solution for 30 seconds, assisted by 100-200W ultrasound. The frequency of the ultrasound-assisted impregnation is 20-40kHz, and the power density is 0.5-1.0W / cm³. 2 Furthermore, the pre-impregnation process employs reciprocating stirring at a speed of 30-50 rpm.

7. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S3, the vacuum degree of vacuum impregnation is adjusted within the range of -0.06 to -0.09 MPa, and 2-3 pressure cycles are performed during the impregnation process. The pressure cycle involves going from atmospheric pressure to the set vacuum degree and then back to atmospheric pressure.

8. The napkin impregnation process with fragrance slow-release function as described in claim 1, characterized in that: In step S3, hot air curing involves drying at 80-100℃ for 5-10 minutes.

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