High-remaining-fragrance microcapsule and preparation method thereof

Abstract

This invention belongs to the field of microencapsulation technology, and specifically relates to a high-lasting fragrance microcapsule and its preparation method. The preparation method of the high-lasting fragrance microcapsule provided by this invention includes the following steps: S101, mixing fragrance with hydrophilic particles and ultrasonically dispersing to obtain an oil phase; S102, mixing styrene-maleic anhydride copolymer, a strong acid-resistant anionic emulsifier, and a nonionic emulsifier, adjusting the pH, and stirring evenly to obtain an aqueous phase; S103, mixing melamine, formaldehyde, water, modifier A, and modifier B, heating and stirring, adjusting the pH, and cooling after the reaction to obtain a modified MF prepolymer; S104, adding the oil phase to the aqueous phase for emulsification to obtain an emulsion; S105, adding the modified MF prepolymer to the emulsion for crosslinking, adjusting the pH for curing, and then adding polyvinyl alcohol polymers and glutaraldehyde for secondary encapsulation to obtain the high-lasting fragrance microcapsule. The fragrance microcapsules prepared by this invention achieve a long-lasting fragrance effect and excellent wash resistance.

Description

Technical Field

[0001] This invention relates to the field of microcapsule technology, and in particular to a high-lasting fragrance microcapsule and its preparation method. Background Technology

[0002] With the improvement of living standards, people have many new demands for the functionality of clothing, such as fragrance, cooling sensation, and antibacterial properties. Microcapsules are small particles containing active ingredients or core substances encapsulated in a coating layer or shell. After microencapsulation, the color, shape, volume, mass, solubility, and storability of special core materials change. Under specific conditions, the core material is slowly released to exert its effects. Applying microencapsulation technology to fabrics can effectively improve their functionality, durability, and comfort.

[0003] In existing processes for manufacturing fabrics loaded with microcapsules, the core material is typically encapsulated with polymer materials to obtain microcapsules, which are then loaded onto the fabric through a finishing process. For example, patent CN114108316B discloses a method for preparing antibacterial textiles and the antibacterial textiles themselves. This patent uses anionic / nonionic composite emulsifiers to prepare plant essential oil emulsions; mixes the plant essential oil emulsions with end-capped cationic aqueous polyurethane emulsions and prepares plant essential oil microcapsules by spray drying; then coats the fabric with a coating solution containing the plant essential oil microcapsules, exhibiting excellent wash resistance.

[0004] For fragrance fabrics loaded with fragrance microcapsules, commercially available fragrance microcapsules are prone to losing some of their top fragrance components during processing due to heat and unstable emulsification interfaces. Furthermore, the commonly used polymer materials used for encapsulation are not dense enough, leading to rapid fragrance evaporation and shortening the lifespan of the microcapsules, thus affecting the consumer's wearing experience. On the other hand, the adhesion of the microcapsules to the fabric surface relies mainly on the adhesive drying process to form a film, resulting in poor wash resistance and further impacting the actual performance of the fabric.

[0005] Therefore, there is an urgent need to provide a fragrance microcapsule with high fragrance retention, high density, and high adhesion. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing high-lasting fragrance microcapsules to solve the problems of short fragrance retention time, poor fabric adhesion, and insufficient washability of existing fragrance microcapsules in related technologies.

[0007] In a first aspect, the present invention provides a method for preparing high-lasting fragrance microcapsules, comprising the following steps: S101, the fragrance is mixed with hydrophilic particles and ultrasonically dispersed to obtain the oil phase; S102, styrene-maleic anhydride copolymer, strong acid resistant anionic emulsifier, and nonionic emulsifier are mixed, the pH is adjusted to 2.5-4.1, and the mixture is stirred evenly to obtain an aqueous phase; S103, melamine, formaldehyde, water, modifier A and modifier B are mixed, heated and stirred, and the pH is adjusted to 8.0-9.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer; wherein modifier A is a mixed solution of gelatin and glutaraldehyde, and modifier B is a polyquaternary ammonium salt; S104, the oil phase is added to the aqueous phase for emulsification to obtain an emulsion; S105 involves adding modified MF prepolymer to an emulsion for cross-linking to form a shell material. The pH is then adjusted to 2.5-4.1 for curing. Subsequently, polyvinyl alcohol polymers and glutaraldehyde are added for secondary encapsulation to obtain high-fragrance microcapsules.

[0008] In some embodiments, in step S101, the mass fractions of each raw material in the oil phase are: 30-100 parts of fragrance and 0.1-1 parts of hydrophilic particles; in step S102, the mass fractions of each raw material in the aqueous phase are: 3-30 parts of styrene-maleic anhydride copolymer, 0.5-5 parts of strong acid-resistant anionic emulsifier, 0.5-5 parts of nonionic emulsifier, and 50-100 parts of water; in step S103, the mass fractions of each raw material in the modified MF prepolymer are: 1-10 parts of melamine, 1-30 parts of formaldehyde, 1-30 parts of water, 0.01-0.5 parts of modifier A, and 0.01-0.5 parts of modifier B.

[0009] In some embodiments, in step S101, the fragrance is an oily fragrance with an oil phase as the main component and a small amount of hydrophilic components.

[0010] In some embodiments, in step S101, the hydrophilic particles are at least one of hydrophilic silica and hydrophilic titanium dioxide particles. The hydrophilic particles can adsorb hydrophilic components in the fragrance.

[0011] In some embodiments, in step S102, the molecular weight of the styrene-maleic anhydride copolymer is not less than 1W.

[0012] In some embodiments, in step S102, the strong acid-resistant anionic emulsifier is a sulfonic acid emulsifier.

[0013] Preferably, the strong acid-resistant anionic emulsifier is at least one of Calfax® DB-45 (sodium dodecyl diphenyl ether disulfonate), Calfax® DBA-70 (71% active C-12 branched diphenyl ether disulfonate), DOWFAX™ 2A1 (sodium dodecyl diphenyl ether disulfonate), DOWFAX™ 8390 (alkyl diphenyl ether disulfonate), and Mersolat® H-95 (sodium secondary alkyl sulfonate).

[0014] In some embodiments, in step S102, the nonionic emulsifier is a polyoxyethylene ether emulsifier.

[0015] Preferably, the nonionic emulsifier is at least one of SAFOL® EN 90 (polyethoxylated fatty alcohol) and OP-10 (octylphenol polyoxyethylene ether-10).

[0016] In some embodiments, in step S103, the modifier B is at least one of PQ-28 (polyquaternium-28), PQ-56 (polyquaternium-56), and PQ-61 (polyquaternium-61).

[0017] In some embodiments, in step S103, the heating temperature is 60-90°C and the time is 70-190 min.

[0018] In some embodiments, in step S104, emulsification is carried out at room temperature, the emulsification speed is 1000-4000 rpm, and the time is 5-30 min.

[0019] In some embodiments, in step S105, the crosslinking time is 10 min-180 min and the curing time is 2-4 h; the secondary coating is performed at room temperature.

[0020] In some embodiments, the polyvinyl alcohol polymer is at least one of PVA1788, PVA1799, PVA2088, and PVA2488.

[0021] The fragrance microcapsules provided by this invention can be applied to textiles through textile padding, impregnation, coating, printing, etc., and can achieve functions such as strong fragrance retention, long-lasting fragrance retention, and high wash resistance.

[0022] The beneficial effects of the technical solution provided by this invention include: 1. High Fragrance Retention: This invention incorporates hydrophilic nanoparticles into the core material, which adsorb the hydrophilic components of the fragrance within the porous structure of the nanoparticles. This reduces the migration of these hydrophilic components into the aqueous phase during the emulsification and encapsulation process, thus preserving the fragrance. The encapsulation process does not involve heating, significantly reducing the loss of low-boiling-point and volatile components in the fragrance. Simultaneously, the use of a compound emulsifier comprising SMA, a strong acid-resistant anionic emulsifier, and a nonionic emulsifier maintains stable and efficient emulsification even under highly acidic conditions. Furthermore, the highly active strong acid-resistant anionic emulsifier enhances the adsorption performance of the modified MF prepolymer at the interface, while the cationic modified MF prepolymer further increases the migration rate to the interface. Combined with the strong acid-catalyzed melamine-formaldehyde crosslinking reaction, rapid encapsulation and a higher encapsulation rate are achieved. Therefore, more effective fragrance components are retained in the microcapsules, resulting in a high fragrance retention effect.

[0023] 2. Long-lasting fragrance: On the one hand, nanoparticles have a slow-release effect on the hydrophilic components in the fragrance; on the other hand, a composite emulsifier system with good emulsification and stability under acidic conditions is used to attract the cationic modified MF prepolymer to react and crosslink rapidly at the interface, forming a denser shell structure; then, the large number of hydroxyl groups of PVA react with the hydroxymethyl groups in the shell that have not yet fully reacted, embedding them into the triaza heterocyclic molecular chain of melamine resin, which improves the airtightness of the microcapsules, resulting in denser microcapsules and achieving a long-lasting fragrance effect.

[0024] 3. High wash resistance: The microcapsules prepared by cationic modified MF prepolymer have a positive charge on their surface, which forms electrostatic adsorption with most fabric substrates (containing a large number of hydroxyl groups, which are negatively charged), improving the adhesion of microcapsules to the fabric substrate surface and increasing the number of washes. Attached Figure Description

[0025] Figure 1 Microscopic photograph of the high-lasting fragrance microcapsules prepared in Example 1. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, the experimental methods in the following examples are conventional methods, and the experimental materials used are all commercially available products.

[0028] This invention provides a method for preparing high-lasting fragrance microcapsules, which can solve the problems of short fragrance retention time and poor adhesion of existing fragrance microcapsules on fabrics.

[0029] This invention provides a method for preparing high-lasting fragrance microcapsules, comprising the following steps: Step S101: By weight, mix 30-100 parts of fragrance with 0.1-1 parts of hydrophilic particles, and disperse by ultrasonication to obtain the oil phase; Step S102: By weight, mix 3-30 parts of styrene-maleic anhydride copolymer, 0.5-5 parts of strong acid resistant anionic emulsifier, 0.5-5 parts of nonionic emulsifier, and 50-100 parts of water, adjust the pH value to 2.5-4.1, stir evenly, and obtain an aqueous phase; Step S103: By weight, mix 1-10 parts of melamine, 1-30 parts of formaldehyde, 1-30 parts of water, 0.01-0.5 parts of modifier A and 0.01-0.5 parts of modifier B, heat and stir at 60-90℃ for 70-190 min, adjust the pH value to 8.0-9.0, and after the reaction is completed, cool down to obtain the modified MF prepolymer; Step S104: Add the oil phase to the aqueous phase at room temperature and emulsify at 1000-4000 rpm for 5-30 min to obtain an emulsion; In step S105, the modified MF prepolymer is added to the emulsion for crosslinking for 10-180 minutes by mass to form a shell. The pH value is adjusted to 2.5-4.1 and cured for 2-4 hours. Then, 0.05-5 parts of polyvinyl alcohol polymer and 0.05-5 parts of aldehyde are added for secondary coating to obtain high-fragrance microcapsules.

[0030] In step S101, the fragrance is an oil-based fragrance; the hydrophilic particles are at least one of hydrophilic silica and hydrophilic titanium dioxide particles.

[0031] In step S102, the strong acid-resistant anionic emulsifier is a sulfonic acid emulsifier, and the nonionic emulsifier is a polyoxyethylene ether emulsifier.

[0032] In step S103, modifier A is a mixed solution of gelatin and glutaraldehyde; modifier B is at least one of PQ-28 (polyquaternium-28), PQ-56 (polyquaternium-56), and PQ-61 (polyquaternium-61).

[0033] The following detailed description of the high-lasting fragrance microcapsules and their preparation method provided by the present invention, with reference to examples and comparative examples, is provided in detail below.

[0034] Example 1: (1) By weight, 50 parts of oily green apple flavoring and 0.25 parts of hydrophilic silica were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 5 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.2W, 0.6 parts of Calfax® DB-45, 2 parts of SAFOL® EN 90 and 100 parts of water, adjust the pH value to 3.0, stir evenly to obtain the aqueous phase; (3) By mass, 1.9 parts of melamine, 5 parts of formaldehyde, 15 parts of water, 0.3 parts of gelatin, 0.2 parts of glutaraldehyde and 0.05 parts of PQ-28 are mixed and heated and stirred at 65°C for 80 min. The pH value is adjusted to 8.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 2000 rpm for 10 min to obtain an emulsion; (5) By mass, the modified MF prepolymer is added to the emulsion for crosslinking for 50 min to form a shell material. The pH value is adjusted to 3.0 and cured for 3 h. Then, 0.2 parts of PVA1788 and 0.8 parts of glutaraldehyde are added at room temperature for secondary coating to obtain high-scent-retaining fragrance microcapsules.

[0035] Microscopic image of the high-lasting fragrance microcapsules prepared in Example 1 is shown below. Figure 1 ,from Figure 1 It can be seen that the flavor microcapsules prepared by the present invention have a regular morphology, no large-scale agglomeration, and the microcapsules as a whole present a regular spherical or near-spherical structure, without obvious adhesion or damage.

[0036] Example 2: (1) By weight, 60 parts of oily green apple flavoring and 0.3 parts of hydrophilic titanium dioxide were mixed and ultrasonically dispersed to obtain the oil phase; (2) By weight, mix 6 parts of styrene-maleic anhydride copolymer with a molecular weight of 2.5W, 3 parts of Calfax® DB-45, 1 part of DOWFAX™ 8390, 0.3 parts of OP-10 and 90 parts of water, adjust the pH value to 4.0, stir evenly to obtain the aqueous phase; (3) By mass, 8 parts of melamine, 28 parts of formaldehyde, 10 parts of water, 0.08 parts of gelatin, 0.3 parts of glutaraldehyde and 0.32 parts of PQ-56 are mixed and heated and stirred at 85°C for 100 min. The pH value is adjusted to 8.5. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 3000 rpm for 20 min to obtain an emulsion; (5) By mass, the modified MF prepolymer is added to the emulsion for cross-linking for 80 min to form a shell material. The pH value is adjusted to 3.5 and cured for 2.5 h. Then, 4 parts of PVA2088 and 0.5 parts of glutaraldehyde are added at room temperature for secondary coating to obtain high-fragrance microcapsules.

[0037] Example 3: (1) By weight, 80 parts of oily green apple flavoring and 0.6 parts of hydrophilic particles were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 5 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.8W, 4 parts of DOWFAX™ 2A1, 3 parts of SAFOL® EN 90 and 70 parts of water, adjust the pH value to 3.0, stir evenly to obtain an aqueous phase; (3) By mass, 3 parts melamine, 9 parts formaldehyde, 5 parts water, 0.03 parts gelatin, 0.06 parts glutaraldehyde and 0.2 parts PQ-61 are mixed and heated and stirred at 75°C for 100 min. The pH value is adjusted to 9.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 3500 rpm for 20 min to obtain an emulsion; (5) By mass, the modified MF prepolymer is added to the emulsion for crosslinking for 120 min to form a shell. The pH value is adjusted to 3.0 and cured for 2.5 h. Then, 0.1 parts of PVA2488 and 0.22 parts of glutaraldehyde are added at room temperature for secondary coating to obtain high-fragrance microcapsules.

[0038] Example 4: (1) By weight, 70 parts of oily green apple flavoring and 0.32 parts of hydrophilic particles were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, 18 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.5W, 0.6 parts of Mersolat® H-95, 0.8 parts of OP-10 and 80 parts of water are mixed, the pH value is adjusted to 2.5, and the mixture is stirred evenly to obtain an aqueous phase; (3) By mass, 5 parts melamine, 16 parts formaldehyde, 16 parts water, 0.12 parts gelatin, 0.36 parts glutaraldehyde and 0.33 parts PQ-56 are mixed and heated and stirred at 85°C for 110 min. The pH value is adjusted to 8.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 3000 rpm for 25 min to obtain an emulsion; (5) By mass, the modified MF prepolymer is added to the emulsion for crosslinking for 50 min to form a shell material. The pH value is adjusted to 3.0 and cured for 2.5 h. Then, 1.8 parts of PVA1788 and 0.32 parts of glutaraldehyde are added at room temperature for secondary coating to obtain high-scent-retaining fragrance microcapsules.

[0039] Example 5: (1) By weight, 65 parts of oily green apple flavoring and 0.33 parts of hydrophilic particles were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 6 parts of styrene-maleic anhydride copolymer with a molecular weight of 2W, 1.2 parts of Calfax® DBA-70, 1.2 parts of OP-10 and 80 parts of water, adjust the pH value to 4, stir evenly to obtain the aqueous phase; (3) By mass, 6.6 parts of melamine, 17.2 parts of formaldehyde, 25 parts of water, 0.2 parts of gelatin, 0.3 parts of glutaraldehyde and 0.06 parts of PQ-28 are mixed and heated and stirred at 65°C for 150 min. The pH value is adjusted to 9.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 1500 rpm for 20 min to obtain an emulsion; (5) By mass, the modified MF prepolymer was added to the emulsion for crosslinking for 60 min to form a shell material. The pH value was adjusted to 2.8 and cured for 3 h. Then, 3.9 parts of PVA1799 and 1.8 parts of glutaraldehyde were added at room temperature for secondary coating to obtain high-fragrance microcapsules.

[0040] Comparative Example 1: (1) By weight, 50 parts of oily green apple flavoring and 0.25 parts of hydrophilic silica were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 5 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.2W, 2 parts of SAFOL® EN90 and 100 parts of water, adjust the pH value to 3.0, stir evenly to obtain an aqueous phase; (3) By mass, 1.9 parts of melamine, 5 parts of formaldehyde, 15 parts of water, 0.3 parts of gelatin, 0.2 parts of glutaraldehyde and 0.05 parts of PQ-28 are mixed and heated and stirred at 65°C for 80 min. The pH value is adjusted to 8.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 2000 rpm for 10 min to obtain an emulsion; (5) By mass, the modified MF prepolymer is added to the emulsion for crosslinking for 50 min to form a shell. The pH value is adjusted to 3.0 and cured for 3 h. Then, 0.2 parts of PVA1788 and 0.8 parts of glutaraldehyde are added at room temperature for secondary coating to obtain the fragrance microcapsules.

[0041] Comparative Example 2: (1) By weight, 50 parts of oily green apple flavoring and 0.25 parts of hydrophilic silica were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 5 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.2W, 0.6 parts of Calfax® DB-45, 2 parts of SAFOL® EN 90 and 100 parts of water, adjust the pH value to 3.0, stir evenly to obtain the aqueous phase; (3) By mass, 1.9 parts of melamine, 5 parts of formaldehyde and 15 parts of water are mixed and heated and stirred at 65°C for 80 min. The pH value is adjusted to 8.0. After the reaction is completed, the temperature is lowered to obtain MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 2000 rpm for 10 min to obtain an emulsion; (5) By mass, add MF prepolymer to emulsion for crosslinking for 50 min to form shell material, adjust pH value to 3.0 and cure for 3 h, then add 0.2 parts PVA1788 and 0.8 parts glutaraldehyde at room temperature for secondary coating to obtain fragrance microcapsules.

[0042] Comparative Example 3: (1) By weight, 50 parts of oily green apple flavoring and 0.25 parts of hydrophilic silica were mixed and ultrasonically dispersed to obtain the oil phase; (2) By mass, mix 5 parts of styrene-maleic anhydride copolymer with a molecular weight of 1.2W, 0.6 parts of Calfax® DB-45, 2 parts of SAFOL® EN 90 and 100 parts of water, adjust the pH value to 3.0, stir evenly to obtain the aqueous phase; (3) By mass, 1.9 parts of melamine, 5 parts of formaldehyde, 15 parts of water, 0.3 parts of gelatin, 0.2 parts of glutaraldehyde and 0.05 parts of PQ-28 are mixed and heated and stirred at 65°C for 80 min. The pH value is adjusted to 8.0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer. (4) Add the oil phase to the aqueous phase at room temperature and emulsify at 2000 rpm for 10 min to obtain an emulsion; (5) By mass, add the modified MF prepolymer to the emulsion for crosslinking for 50 min to form a shell material, adjust the pH value to 3.0 and cure for 3 h to obtain high fragrance microcapsules.

[0043] Performance testing: The fragrance microcapsules of Examples 1-5 and Comparative Examples 1-3 were diluted with water to prepare a microcapsule aqueous solution with a mass concentration of 10%. Aqueous acrylic resin and fatty alcohol polyoxyethylene ether were added. The microcapsule aqueous solution was then applied to cotton fabric, and the cotton fabric was subjected to a water wash resistance test to examine the fragrance retention of the cotton fabric after multiple washes. The results are shown in Table 1. The full score for fragrance retention in Table 1 is set at 10 points. The score was determined based on the sensory fragrance retention before and after washing.

[0044] Table 1: Wash resistance test results of Examples 1-5 and Comparative Examples 1-3

[0045] As can be seen from Table 1, the fragrance microcapsules prepared in Examples 1-5 of this invention have a fragrance retention score of 7.6-8.8. The high fragrance retention microcapsules prepared initially have a rich fragrance retention, and after 10 machine washes, the fragrance retention score is 2.2-3.5, showing excellent water resistance.

[0046] The fragrance microcapsules of Comparative Example 1 without the addition of a strong acid-resistant anionic emulsifier scored 7.1 points and 2.1 points in fragrance retention after 10 machine washes, respectively, both lower than those of the fragrance microcapsules of Example 1. The inventors analyzed that this is because the addition of a strong acid-resistant anionic emulsifier can still maintain a stable and efficient emulsification effect under strong acid conditions, enhance the adsorption performance of the interface on the modified MF prepolymer, and the strong acid conditions catalyze the melamine-formaldehyde crosslinking reaction, which can achieve rapid encapsulation and a higher encapsulation rate, so that more of the effective fragrance components in the microcapsules are retained, achieving a high fragrance retention effect.

[0047] Comparative Example 2, the fragrance microcapsules without shell modification scored 7.3 points and 1.5 points in fragrance retention after 10 machine washes, respectively, both lower than the fragrance microcapsules of Example 1. The inventors analyzed that this is because the cationic modified MF prepolymer can form a denser shell structure with better encapsulation of the core material. On the other hand, the microcapsules prepared by the cationic modified MF prepolymer have a positively charged surface, which forms electrostatic adsorption with the fabric substrate, improving the adhesion of the microcapsules to the fabric substrate surface, thereby increasing the number of washes.

[0048] The fragrance retention of Comparative Example 3, which did not contain polyvinyl alcohol and glutaraldehyde, was 6.8 points and 1.8 points after 10 machine washes, respectively, both lower than that of the fragrance microcapsules in Example 1. The inventors analyzed that this was because after adding polyvinyl alcohol, a large number of hydroxyl groups in polyvinyl alcohol reacted with the hydroxymethyl groups in the shell material that had not yet fully reacted, embedding them into the triazine heterocyclic molecular chain of melamine resin, which improved the airtightness of the microcapsules, resulting in denser microcapsules and achieving a long-lasting fragrance effect.

[0049] In summary, the test results of Examples 1-5 and Comparative Examples 1-3 demonstrate that the technical solution of the present invention achieves a long-lasting fragrance effect through the synergistic effect of each component, and exhibits excellent water-wash resistance.

[0050] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0051] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0052] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method for preparing a high-lasting fragrance microcapsule, characterized in that, Includes the following steps: S101, the fragrance is mixed with hydrophilic particles and ultrasonically dispersed to obtain the oil phase; S102, styrene-maleic anhydride copolymer, strong acid resistant anionic emulsifier, and nonionic emulsifier are mixed, the pH is adjusted to 2.5-4.1, and the mixture is stirred evenly to obtain an aqueous phase; S103, melamine, formaldehyde, water, modifier A and modifier B are mixed, heated and stirred, and the pH is adjusted to 8.0-9.

0. After the reaction is completed, the temperature is lowered to obtain the modified MF prepolymer; wherein modifier A is a mixed solution of gelatin and glutaraldehyde, and modifier B is a polyquaternary ammonium salt; S104, the oil phase is added to the aqueous phase for emulsification to obtain an emulsion; S105, the modified MF prepolymer is added to the emulsion for cross-linking reaction, the pH is adjusted to 2.5-4.1 for curing, and then polyvinyl alcohol polymer and glutaraldehyde are added for secondary coating to obtain the high-fragrance microcapsules.

2. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S101, the fragrance is an oil-based fragrance; the hydrophilic particles are at least one of hydrophilic silica and hydrophilic titanium dioxide particles.

3. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S102, the strong acid-resistant anionic emulsifier is a sulfonic acid emulsifier, selected from at least one of Calfax® DB-45, Calfax® DBA-70, DOWFAX™ 2A1, DOWFAX™ 8390, and Mersolat® H-95; the nonionic emulsifier is a polyoxyethylene ether emulsifier, selected from at least one of SAFOL® EN 90 and OP-10.

4. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S103, the modifier B is at least one of polyquaternium-28, polyquaternium-56, and polyquaternium-61.

5. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S101, the mass fractions of each raw material in the oil phase are: 30-100 parts of fragrance and 0.1-1 parts of hydrophilic particles; in step S102, the mass fractions of each raw material in the aqueous phase are: 3-30 parts of styrene-maleic anhydride copolymer, 0.5-5 parts of strong acid-resistant anionic emulsifier, 0.5-5 parts of nonionic emulsifier, and 50-100 parts of water; in step S103, the mass fractions of each raw material in the modified MF prepolymer are: 1-10 parts of melamine, 1-30 parts of formaldehyde, 1-30 parts of water, 0.01-0.5 parts of modifier A, and 0.01-0.5 parts of modifier B.

6. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S105, the polyvinyl alcohol polymer is selected from at least one of polyvinyl alcohol 1788, polyvinyl alcohol 1799, polyvinyl alcohol 2088, and polyvinyl alcohol 2488.

7. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S103, the heating temperature is 60-90℃ and the time is 70-190min.

8. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S104, the emulsification speed is 1000-4000 rpm and the time is 5-30 min.

9. The method for preparing high-lasting fragrance microcapsules according to claim 1, characterized in that, In step S105, the crosslinking time is 10 min-180 min, and the curing time is 2-4 h; the secondary coating is carried out at room temperature.

10. A high-lasting fragrance microcapsule, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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