Composite microspheres possessing moisture-absorbing, antibacterial, and deodorizing functions, a method for preparing them, and their uses.

Abstract

Belonging to the field of functional materials synthesis, this invention provides composite microspheres possessing moisture-absorbing, antibacterial, and deodorizing functions, as well as methods for preparing them and their applications. [Solution] The composite microspheres contain the following parts by weight of preparation raw materials: 50-80 parts moisture-absorbing base material, 10-20 parts antimicrobial and antifungal agent, 5-10 parts moisture absorption and deodorizing enhancer, and 1-5 parts crosslinking agent. During preparation, the finished product is obtained through pre-mixing, high-speed shear dispersion, crosslinking reaction, and post-treatment. These microspheres are multifunctional, have high moisture absorption capacity, are environmentally friendly and recyclable, are process-controllable, and can be used in the field of functional textiles.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional material synthesis, and specifically relates to composite microspheres that combine moisture absorption, antibacterial and deodorant functions, a preparation method thereof, and uses thereof.

Background Art

[0002] In application scenarios such as humid climates, enclosed spaces (clothing storage, warehouses, automotive interiors, etc.), or functional products (functional textiles, packaging materials, etc.), when humidity exceeds the allowable range, it is likely to cause mold growth due to moisture and performance degradation (hardening of textiles, decrease in strength of packaging materials, etc.) of articles. Furthermore, the propagation of microorganisms (bacteria, mold) will produce malodor, which seriously affects user experience and the service life of articles.

[0003] Currently, the mainstream moisture-absorbing materials on the market are mainly inorganic desiccants such as silica gel, montmorillonite, and calcium chloride. Although these materials have relatively low cost, they have the following remarkable limitations: First, they have a single function, only capable of basic moisture absorption, cannot inhibit the growth of microorganisms or remove malodors, and require separate combination of antibacterial agents and deodorants, which complicates the application process and easily causes compatibility problems between components. Second, the moisture absorption capacity is limited: the equilibrium moisture absorption rate of silica gel is usually less than 30%, and it is prone to caking and deliquescence after moisture absorption, making it difficult to reuse. Third, the morphological adaptability is low: most of them are powder or lumps, have poor fluidity when bulk-filled and are difficult to uniformly disperse. Especially in the field of functional textiles, they have weak adhesion to fiber substrates and are prone to falling off and loss.

[0004] In response to the demand for multifunctionality, some composite hygroscopic materials have emerged using conventional technology, but significant challenges remain: Firstly, the synergistic effects between components are insufficient; for example, some antimicrobial agents (such as quaternary ammonium salts) and hydrophilic substrates (such as starch) exhibit antagonistic effects, potentially destroying the hydrophilic groups of the substrate and reducing hygroscopic performance. Secondly, environmental compatibility and safety are insufficient; many composite systems rely on chemically synthesized polymers (such as polyacrylates) as carriers, resulting in low biodegradability, and some antimicrobial components (such as high concentrations of silver ions) pose potential ecological risks. Thirdly, the manufacturing process is complex, with techniques such as emulsion polymerization and direct polymerization commonly used, requiring precise control of numerous parameters such as reaction temperature and pH value, resulting in high capital investment and difficulty in large-scale production. Fourthly, circulation stability is low; some materials tend to collapse after 1-2 hygroscopic-drying cycles, leading to performance degradation exceeding 50% and failing to meet long-term use requirements.

[0005] As described above, there is an urgent need for a novel composite material that integrates three core functions—high-efficiency moisture absorption, broad-spectrum antibacterial action, and powerful deodorization—while also being environmentally friendly, having good component compatibility, a controllable preparation process, adaptable to bulk packaging / compound applications, and being recyclable. This material is required to solve the problem of coordinated management of humidity, microorganisms, and odors in various situations. [Overview of the project]

[0006] The object of the present invention is to solve the problems that conventional hygroscopic materials have a single function and low moisture absorption capacity, and that some multifunctional materials have insufficient synergistic effects, are morphologically unsuitable, or have complex preparation processes, and to provide composite microspheres that have moisture absorption, antibacterial, and deodorizing functions, as well as a method for preparing them and their applications.

[0007] To achieve the above objective, the present invention provides a composite microsphere having moisture-absorbing, antibacterial, and deodorizing functions, characterized by comprising a preparation raw material in parts by weight of 50 to 80 parts of a moisture-absorbing base material, 10 to 20 parts of an antimicrobial and antifungal agent, 5 to 10 parts of a moisture-absorbing and deodorizing enhancer, and 1 to 5 parts of a crosslinking agent.

[0008] Preferably, the preparation contains parts by weight of 60 parts of a moisture-absorbing base material, 15 parts of an antimicrobial and antifungal agent, 8 parts of a moisture-absorbing and deodorizing enhancer, and 3 parts of a crosslinking agent.

[0009] Preferably, the moisture-absorbing substrate is a hydrophilic polysaccharide. The hydrophilic polysaccharides mentioned above are seaweed polysaccharides or carboxymethylated starch.

[0010] Preferably, the antimicrobial agent is chitosan or polydimethyldiallylammonium chloride.

[0011] Preferably, the moisture-absorbing and deodorizing enhancer is nano MoS2 or silver ion exchange zeolite.

[0012] Preferably, the crosslinking agent is epichlorohydrin or glutaraldehyde.

[0013] Based on the same technical concept, the present invention relates to a method for preparing composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions, the preparation method comprising the following steps: (1) Add the moisture-absorbing substrate and antibacterial / antifungal agent to the solvent to obtain a preliminary mixed solution. (2) Add a moisture-absorbing and deodorizing enhancer to the pre-mixed solution and perform high-speed shearing to obtain a dispersion solution. (3) Add a crosslinking agent to the dispersion solution and carry out a crosslinking reaction to obtain gel microspheres. (4) Post-treatment is performed on the gel microspheres to obtain composite microspheres having the hygroscopic, antibacterial, and deodorizing functions.

[0014] Preferably, in step (1), the solvent is an acidic aqueous solution or a neutral aqueous solution, and the acidic aqueous solution is an aqueous acetic acid solution with a concentration of 1-5% wt. and / or, in step (2), the rotational speed of the high-speed shear is 1000 to 2000 r / min, and the time is 30 to 35 min. and / or, in step (3), the temperature of the crosslinking reaction is 60-70°C and the time is 2-3 hours. and / or, in step (4), the post-treatment is shape fixing, curing, and drying.

[0015] Based on the same technical concept, the present invention further provides applications for composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions in the field of preparing functional textile products. [Effects of the Invention]

[0016] The present invention has the following beneficial effects. This invention uses natural hydrophilic polysaccharides as a base material, combines it with functional additives in a coordinated manner, and employs a "high-speed shear dispersion-crosslinking molding-freeze-drying" process to construct composite microspheres with a porous network structure. This achieves the coordinated integration of "moisture absorption-antibacterial-deodorizing" functions, while also possessing environmental friendliness, recyclability, and process scalability, thus filling the gap in the field of multi-functional, highly adaptable moisture-absorbing materials that has been present in conventional technologies. 1. Solve the problems of functional monolithic and cooperative antagonism and achieve effective integration. Each component of the complex microspheres has a clear role and works synergistically: hydrophilic polysaccharides (seaweed polysaccharides / carboxymethylated starch) provide sufficient hydrophilic groups, ensuring basic moisture absorption capacity; antimicrobial and antifungal agents (chitosan / polydimethyldiallylammonium chloride) exert broad-spectrum bacteriostatic activity by disrupting microbial cell membranes, and have good compatibility with the substrate without performance antagonism; and moisture absorption and deodorizing enhancers (nano MoS2 / silver ion exchange zeolite) not only improve moisture absorption rate through their porous structure but also adsorb and catalyze the decomposition of malodorous molecules (NH3, H2S, etc.). By combining these three components, the microspheres possess high moisture absorption, strong antibacterial properties, and rapid deodorizing ability, avoiding the functional fragmentation caused by conventional "multi-material mixtures." 2. Overcoming the bottlenecks of moisture absorption capacity and morphological adaptability, enabling application in a variety of situations. The "high-speed shear dispersion" in the preparation process ensures uniform dispersion of auxiliary agents, and "freeze-drying" maintains the porous network structure after ice crystal sublimation. The specific surface area of ​​the microspheres is improved to 3-5 times that of conventional silica gel, and the moisture absorption rate in a 30°C / 80%RH environment is over 30% (significantly exceeding the 15-20% of silica gel, based on the composite microspheres). Furthermore, the moisture absorption rate of the felt reaches 4.94%, significantly exceeding the control product's 1.79% (based on felt). At the same time, the particle size of the microspheres is controllable (1-2 mm), providing excellent fluidity and enabling bulk filling in warehouses, clothing storage facilities, etc. It can also bond with the fibers of spun products through the dyeing and finishing process, solving the adaptability problems of conventional materials such as "consolidation and shedding." Here, moisture absorption rate is synonymous with repellency, and refers to the percentage of the mass of water contained in a substance relative to the "completely dry mass" (dry mass) of that substance. 3. Achieve both environmental friendliness and circularity, and reduce usage costs. The core ingredients (seaweed polysaccharides, chitosan) are derived from natural biomass, are highly biodegradable, pose no risk of chemical residue, and the microspheres, after drying at 105°C, fully recover their porous structure, retaining over 90% of their moisture absorption and antibacterial properties. They can be reused more than 50 times, reducing usage costs by 60-70% compared to conventional disposable desiccants, thus meeting the requirements for green and low-carbon development. 4. Simplify the preparation process and enable large-scale production. The preparation process consists of only five steps: pre-mixing, dispersion, crosslinking, molding, and post-treatment. The process parameters are clear (high-speed shear rotation speed of 1000-2000 r / min, crosslinking temperature of 60-70°C, and reaction time of 2-3 hours). It does not require complex polymerization equipment, and the molding method is flexible (both drip freezing and spray freezing are possible). Continuous production is possible with the spray freezing method, resulting in a 2-3 times improvement in production efficiency compared to conventional processes, making it suitable for industrialization and widespread adoption. [Brief explanation of the drawing]

[0017] To more clearly describe the technical solutions of the embodiments of the present invention or the prior art, the following briefly describes the drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these accompanying drawings without creative efforts. [Figure 1] It is a microscopic schematic diagram of water absorption gelation of seaweed polysaccharide of the composite microspheres of the present invention.

Mode for Carrying Out the Invention

[0018] To clarify the objectives, technical solutions and advantages of the present invention, the technical solutions of the present invention are described in detail below. Obviously, the described embodiments are only some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

Examples

[0019] This example provides a method for preparing composite microspheres that combine moisture absorption, antibacterial and deodorant functions. The composite microspheres are based on natural polymer materials, and products with specific functions and microscopic structures are constructed through chemical crosslinking and physical molding techniques.

[0020] Figure 1 is a microscopic schematic diagram of water absorption gelation of seaweed polysaccharide of the composite microspheres of the present invention, showing its excellent water absorption effect. It can not only absorb hundreds of times its own weight in water, but also form a stable hydrogel through ionic crosslinking and firmly retain water. This property goes beyond mere "water absorption" and reaches the level of "gelation" and "intelligent response", and plays an indispensable role in high value-added fields such as medical treatment, food and agriculture.

[0021] Specifically, the raw material components for preparing the composite microspheres include a hydrophilic polysaccharide as a moisture-absorbing substrate, a component as an antibacterial and antifungal agent, a component as a moisture absorption enhancer and a deodorizing filler, and a crosslinking agent for constructing a network structure. In one embodiment of the present invention, as a preferred combination, an algal polysaccharide is used as the hydrophilic polysaccharide, chitosan is used as the antibacterial agent, nano molybdenum disulfide is used as the moisture absorption enhancer and the deodorizing filler, and epichlorohydrin is used as the crosslinking agent.

[0022] To facilitate understanding of the present invention, the functions of the related components are described as follows: As a substrate, the algal polysaccharide has a large number of hydrophilic functional groups, mainly hydroxyl groups and carboxyl groups, densely distributed on its molecular chains. When the composite microspheres contact humid air, water molecules in the air are captured in two main ways: firstly, as polar molecules, water molecules form hydrogen bonds with hydroxyl groups on the molecular chains of algal polysaccharide and are physically adsorbed; secondly, water molecules undergo strong hydration with carboxyl groups and their corresponding cations to form hydrated ions, which are further firmly retained in the network structure. Due to the synergistic effect of these two actions, the microsphere substrate itself has a strong moisture absorption capacity.

[0023] When contaminated air containing water molecules and malodorous molecules passes through a packed bed formed by stacking a large number of composite microspheres, water molecules are efficiently absorbed by the hydrophilic substance skeleton (mainly algal polysaccharide) inside the microspheres, and malodorous molecules may be adsorbed, catalyzed and decomposed by functional fillers (such as nano molybdenum disulfide) dispersed in the skeleton. At the same time, antibacterial components (such as chitosan) that are part of the skeleton inhibit bacteria and molds that may grow due to moisture. Ultimately, the gas exiting the microspheres becomes clean and dry air. Therefore, the multi-functional integrated property of the microspheres derives from the porous network structure jointly constructed by the internal hydrophilic substance skeleton and the functional filler.

[0024] This embodiment further provides a method for preparing composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions, the method mainly comprising the steps of dissolving polysaccharides and an antibacterial agent, adding and dispersing a filler, adding and reacting a crosslinking agent, freeze-molding, vacuum freeze-drying, and curing treatment, specifically, Dissolution of polysaccharides and antibacterial agents: 60 g of seaweed polysaccharide powder and 15 g of chitosan powder are precisely weighed and added to a reactor containing 100 g of solvent. In this example, the solvent used is a 2% aqueous acetic acid solution. The reason for using an aqueous acetic acid solution is that, while chitosan has low solubility in water, under acidic conditions the amino groups on its molecular chains are protonated to ammonium ions, breaking the hydrogen bonds between the molecular chains and allowing for good dissolution. The reaction vessel is placed in a magnetic stirrer and continuously stirred at 500 rpm for about 4 hours at room temperature (approximately 25°C) until all the powder is completely dissolved, forming a uniform, transparent, pale yellow, viscous polymer solution free of visible particles. At this time, the molecular chains of the seaweed polysaccharides and chitosan are sufficiently extended in the solution, laying the foundation for subsequent reactions.

[0025] Addition and Dispersion of Filler: While maintaining stirring, 8 g of nanomolybdenum disulfide powder is gradually added to the polymer solution. The average particle size of the nanomolybdenum disulfide powder is approximately 50-100 nm, and it has a very large specific surface area and excellent adsorption catalytic performance. To ensure that the nanoparticles are uniformly dispersed in the viscous polymer substrate and that aggregation does not occur, the mixture is transferred to a high-speed shear disperser, the rotation speed is set to 1500 rpm, and high-speed shearing is performed for 30 minutes. The strong shear force effectively breaks up aggregates of nanoparticles, coating their surface with polymer molecules and forming a stable suspension dispersion system. After processing, a uniformly colored dark gray viscous mixture is obtained.

[0026] Addition of crosslinking agent and reaction: The dark gray mixture is returned to a reactor with heating and stirring capabilities, and the temperature is set to 65°C. While continuously stirring, 3 g of epichlorohydrin is gradually added to the mixture using a dropping funnel. As a crosslinking agent, the epoxy groups and chlorine atoms at both ends of the epichlorohydrin molecule undergo ring-opening addition or substitution reactions with the hydroxyl groups and amino groups on the seaweed polysaccharide and chitosan molecular chains, respectively, achieving chemical crosslinking, or "crosslinking," between different polymer molecular chains. After the addition is complete, the reaction is carried out at 65°C for 2 hours. As the crosslinking reaction progresses, the fluidity of the solution gradually decreases, eventually losing all fluidity and forming a pair of elastic gels, which indicates the preliminary formation of a three-dimensional network structure.

[0027] Freeze-molding: The gel obtained in the previous step is transferred to a capillary dispensing device (syringe or peristaltic pump) with a diameter of 0.1 mm. A Dewar flask containing a sufficient amount of liquid nitrogen (temperature approximately -196°C) is prepared. The dispensing device is activated so that the gel is pushed out of the capillary at a uniform rate to form droplets, which then fall into the liquid nitrogen under their own gravity. Because the temperature of the liquid nitrogen is extremely low, the gel droplets freeze rapidly the moment they come into contact with the liquid nitrogen, and the water inside them hardens rapidly into tiny ice crystals, while the droplets are fixed in a spherical shape. This rapid freezing is key to the subsequent formation of the porous structure, as it prevents water from forming large ice crystals and ensures the fineness and uniformity of the final pore size. Through this step, a large number of dispersed solid frozen microspheres are obtained.

[0028] Vacuum freeze-drying: The obtained frozen microspheres are immediately transferred to a vacuum freeze-dryer. The apparatus is activated, and first the freeze trap temperature is lowered to below -50°C, then the sample chamber is evacuated and the pressure is reduced to below 10 Pa. Under high vacuum conditions, the sample is programmed to rise to a temperature, for example, slowly rising from -50°C to room temperature (25°C) over 24 hours. During this process, the solid ice crystals inside the microspheres sublimate directly into water vapor without passing through the liquid phase and are captured in the freeze trap. The spaces remaining after the ice crystals sublimate form interconnected large and small pores. Vacuum freeze-drying completely preserves the ice crystal template structure formed in the rapid freezing step, resulting in dried microspheres with high porosity and a huge specific surface area.

[0029] Hardening Treatment: To further improve the mechanical strength and chemical stability of the composite microspheres, a hardening treatment is performed on the microspheres after freeze-drying. Specifically, a 5% (mass / volume) sodium hydroxide ethanol solution is prepared, and the freeze-dried microspheres are immersed in the solution for 1 hour. This step neutralizes any residual acetic acid in the system, potentially promoting further completion of the crosslinking reaction or stabilization of structures such as ester bonds, thereby enhancing the stability of the network framework. The reason for using ethanol instead of water as the solvent is to avoid the collapse of the porous structure due to the high surface tension of water during the treatment process. After the hardening treatment is complete, the microspheres are removed and repeatedly washed with a large amount of deionized water until the pH of the washing solution becomes neutral (approximately 7), completely removing any remaining sodium hydroxide, ethanol, and other unreacted small molecules. Finally, the washed microspheres are dried in a 60°C dryer until they reach a certain weight.

[0030] The macroscopic morphology of the final multi-functional composite microsphere product is spherical particles with a diameter of approximately 1-2 millimeters, possessing good fluidity and lamination properties, making it suitable for use as a bulk-packed functional material. Performance test results indicate the following performance and advantages of the composite microspheres manufactured in this example: (i) High hygroscopicity: Under a 30°C / 80%RH environment, the moisture absorption rate is ≥30% (GB / T 9994-2018). Note that the moisture absorption rate of ≥30% is a value based on the detection of the composite microspheres themselves. (ii) Antimicrobial and antifungal properties: Antimicrobial activity against Escherichia coli and Aspergillus oryzae ≥ 99% (GB / T 33610.2-2017). (iii) Reusability: After drying at 105°C, the moisture absorption capacity is restored (90% performance retention rate after 50 cycles). [Examples]

[0031] The technical solution of this application is not limited to the specific combination of raw materials employed in Example 1. As an alternative embodiment, this example employs different raw materials to produce composite microspheres with similar functions.

[0032] In this example, carboxymethylated starch is used as the hydrophilic polysaccharide, which is a common modified starch with carboxymethyl groups introduced into its molecular chain, and similarly contains abundant hydrophilic groups such as hydroxyl groups and carboxyl groups. Polydimethyldiallylammonium chloride is used as the antibacterial agent, which is a high molecular weight quaternary ammonium salt-based synthetic antibacterial agent with high efficiency and broad-spectrum bactericidal ability. Silver ion exchange zeolite is used as the moisture absorption enhancer and deodorizing filler, where the porous structure of the zeolite itself contributes to moisture absorption and odor adsorption, and the silver ions exchanged within its framework are slowly released, exhibiting antibacterial activity for a long period of time. Glutaraldehyde is used as the crosslinking agent.

[0033] The specific preparation procedure is the same as in Example 1, and is outlined below: Step (1): Weigh 70 g of carboxymethylated starch and 5 g of polydimethyldiallylammonium chloride, dissolve them in deionized water, and stir until a homogeneous solution is formed. Since both of these raw materials have good water solubility, it is not necessary to use an acidic solvent.

[0034] Step (2): Add 15 g of silver ion exchange zeolite powder to the above solution and disperse it using the same high-speed shearing method as in Example 1 to ensure a uniform distribution of zeolite particles.

[0035] Step (3): Add 4 g of glutaraldehyde as a crosslinking agent to the uniformly dispersed mixture. Since the crosslinking reaction between glutaraldehyde and hydroxyl groups is more efficient under weakly acidic conditions, adjust the pH of the solution to 5-6 using a small amount of acid. Then, heat the mixture at 60°C for 3 hours to form a gel. Both the reaction temperature and time here are within the preferred parameter range of the present invention.

[0036] Steps (4) to (6): The subsequent molding, drying, and curing steps are exactly the same as in Example 1. That is, the gel is rapidly freeze-molded by dropping it into liquid nitrogen, then vacuum freeze-drying is performed to construct a porous structure, and finally curing, washing, and drying are performed with a sodium hydroxide ethanol solution.

[0037] In this embodiment as well, a multifunctional composite microsphere having a porous network structure is ultimately obtained. Its moisture absorption function is mainly provided by the carboxymethylated starch substrate, its antibacterial function is provided by the coordinated action of polydimethyldiallylammonium chloride and silver ions, and its deodorizing and auxiliary moisture absorption functions are provided by the porous structure of the zeolite. From the above, the definitions of functional components such as "hydrophilic polysaccharides," "antibacterial agents," and "moisture absorption enhancers and deodorizing fillers" in the proposed solution of this application are reasonable and encompass multiple feasible material selections, thereby ensuring a broad scope of protection. [Examples]

[0038] In order to verify the effectiveness of the preferred formulation range limited by the proposed method of this application, this embodiment is manufactured using a formulation close to the boundary of the range. In this embodiment, the same types of raw materials as in Example 1 are used, but the weight parts of each component are adjusted.

[0039] In this example, the formulation of each raw material is as follows: 80 parts by weight of seaweed polysaccharides (close to the upper limit of 50-80 parts), 20 parts by weight of chitosan (reaching the upper limit of 10-20 parts), 5 parts by weight of nanomolybdenum disulfide (reaching the lower limit of 5-10 parts), and 1 part by weight of epichlorohydrin (reaching the lower limit of 1-5 parts).

[0040] The preparation method follows the same procedure as in Example 1, and the specific process parameters are as follows: Step (1): Dissolve 80g of seaweed polysaccharide and 20g of chitosan in an appropriate amount of 2% aqueous acetic acid solution and stir to form a polymer solution.

[0041] Step (2): Add 5 g of nanomolybdenum disulfide to the solution and perform high-speed shear dispersion.

[0042] Step (3): Add 1 g of epichlorohydrin to the mixture, raise the reaction temperature to 70°C, and allow the mixture to react at a constant temperature for 2 hours to form a gel.

[0043] Steps (4) to (6): The subsequent steps of liquid nitrogen freeze-molding, vacuum freeze-drying, curing, washing, and drying are all the same as in Example 1.

[0044] In this example, the total content of hydrophilic polymers (seaweed polysaccharides and chitosan) is relatively high, reaching 100 parts by mass, and the amount of functional fillers and crosslinking agents used is relatively low. Therefore, it is expected that the resulting composite microspheres will exhibit more outstanding moisture absorption and antibacterial properties. As can be seen from the experimental results, the microspheres produced with this formulation have extremely high moisture absorption capacity and excellent antibacterial effect, while simultaneously maintaining good structural integrity and deodorizing ability. From the above results, it is shown that the formulation range limited in this application is scientifically sound and effective, and any adjustments within this range can achieve the technical objectives of this application, and it is possible to focus on optimizing specific performance according to specific requirements. [Examples]

[0045] This embodiment provides an alternative embodiment of the freeze-molding step (4) in Example 1, illustrating the flexibility of the key steps in the preparation method of this application, and this embodiment is more suitable for industrialized continuous production.

[0046] In this example, the type of raw materials, formulation, and steps (1) (solution preparation), (2) (filler dispersion), and (3) (crosslinking reaction) are all exactly the same as in Example 1, thereby preparing a dark gray viscous gel to be molded, identical to that in Example 1.

[0047] The difference in this embodiment lies in the embodiment of step (4) (freeze molding), where a spray freezing method is adopted instead of the drop method into liquid nitrogen used in Example 1. The specific operation is as follows: The prepared gel is loaded into the feed tank of the spray dryer and sent to the spray nozzle using a peristaltic pump. The nozzle atomizes the gel into fine droplets and sprays them into a drying tower filled with cold air (or nitrogen gas) at a temperature of -40°C or lower. The gel droplets come into sufficient contact with the cold airflow during their fall, and heat is rapidly removed, so they freeze rapidly into solid microspheres before reaching the collector.

[0048] The subsequent steps (5) (vacuum freeze-drying) and (6) (curing treatment) are exactly the same as in Example 1. The obtained frozen microspheres are vacuum freeze-dried to form a porous structure, and then cured, washed and dried to obtain the final composite microsphere product.

[0049] By employing the spray freezing method, continuous operation of the microsphere preparation process is possible, and production efficiency far exceeds that of the batch-type drop method. Simultaneously, by adjusting parameters such as nozzle pore size, feeding rate, and gas flow rate, the particle size and distribution of the resulting microspheres can be controlled more precisely and uniformly. Despite the different molding methods, the core principle—rapid freezing to form a micro-ice crystal template—remains the same, allowing for the production of composite microspheres with similarly microscopic porous structures. It should be understood that the protection of the method described in this application should not be limited to specific equipment or operating procedures.

[0050] As described above, the multifunctional composite microspheres and their preparation method provided in the embodiments of this application successfully integrate multiple functions such as high-efficiency moisture absorption, broad-spectrum antibacterial properties, and powerful deodorization by combining the scientific selection and formulation of raw material components with a unique cross-linking-freeze-drying process, thereby obtaining a novel functional material with excellent overall performance. This material not only has outstanding performance, but its raw material sources are environmentally friendly, its preparation process is controllable, and it has high practical application value and broad market prospects.

[0051] <Comparative Example 1> The difference between this comparative example and Example 1 is that in Comparative Example 1, no antimicrobial agent was added, and all other operations were the same as in Example 1.

[0052] <Comparative Example 2> The difference between this comparative example and Example 1 is that in Comparative Example 2, no moisture-absorbing and deodorizing enhancer was added, but all other operations were the same as in Example 1.

[0053] <Application Examples> The composite microspheres with moisture-absorbing, antibacterial, and deodorizing functions prepared in Example 1 were post-treated onto gray felt (the sample to be tested) using a standard staining and finishing method, and a moisture absorption rate test was performed, specifically as follows: (i) The test sample shall include the sample to be tested, commercially available moisture-proof felt, and gray felt. (2) Purpose of the test: 1. Measure the weight increase of commercially available moisture-proof felt and the sample to be tested (compared to gray felt), 2. Measure the moisture absorption rate and deodorizing performance of the moisture-absorbing pad under constant temperature and humidity conditions. (3) The test results are shown in Tables 1, 2, and 3. JPEG0007922978000002.jpg50170JPEG0007922978000003.jpg51170JPEG0007922978000004.jpg29170

[0054] As can be seen from Tables 1 and 2, the weight ratio of microspheres in commercially available conventional moisture-proof felt is higher than that of the sample to be tested in the present invention, but its moisture absorption rate and deodorization rate are still lower than those of the sample to be tested in the present invention. This indicates that the composite microspheres of the present invention are superior in terms of moisture absorption rate and deodorization rate (note that the moisture absorption rate in Table 2 is based on felt detection). As can be seen from Table 3, the water absorption amount and water absorption rate of the sample to be tested in this invention are far superior to those of commercially available conventional moisture-proof felts.

[0055] Although specific embodiments of the present invention have been described above, the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that a person skilled in the art would readily conceive of within the technical scope disclosed by the present invention should all be included within the scope of protection of the present invention. Accordingly, the scope of protection of the present invention shall be subject to the scope of protection set forth in the claims.

Claims

1. The preparation contains 50 to 80 parts by weight of moisture-absorbing base material, 10 to 20 parts of antibacterial and antifungal agent, 5 to 10 parts of moisture-absorbing and deodorizing enhancer, and 1 to 5 parts by weight of crosslinking agent. The aforementioned moisture-absorbing substrate is a hydrophilic polysaccharide. A composite microsphere having hygroscopic, antibacterial, and deodorizing functions, characterized in that the hydrophilic polysaccharide is a seaweed polysaccharide or carboxymethylated starch.

2. A composite microsphere having moisture-absorbing, antibacterial, and deodorizing functions according to claim 1, characterized in that it contains a preparation raw material in parts by weight of 60 parts moisture-absorbing base material, 15 parts antimicrobial and antifungal agent, 8 parts moisture-absorbing and deodorizing enhancer, and 3 parts crosslinking agent.

3. The composite microsphere having hygroscopic, antibacterial, and deodorizing functions according to claim 1 or 2, characterized in that the antimicrobial and antifungal agent is chitosan or polydimethyldiallylammonium chloride.

4. The composite microsphere having moisture absorption, antibacterial, and deodorizing functions according to claim 1 or 2, characterized in that the moisture absorption and deodorizing enhancer is nano MoS2 or silver ion exchange zeolite.

5. The composite microsphere having moisture-absorbing, antibacterial, and deodorizing functions according to claim 1 or 2, characterized in that the crosslinking agent is epichlorohydrin or glutaraldehyde.

6. A method for preparing composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions as described in claim 1, the preparation method comprising the following steps: (1) Add the moisture-absorbing substrate and antibacterial / antifungal agent to the solvent to obtain a preliminary mixed solution. (2) Add a moisture-absorbing and deodorizing enhancer to the pre-mixed solution and perform high-speed shearing to obtain a dispersion solution. (3) Add a crosslinking agent to the dispersion solution and perform a crosslinking reaction to obtain gel microspheres. (4) Post-treatment is performed on the gel microspheres to obtain composite microspheres having the hygroscopic, antibacterial, and deodorizing functions. A method for preparing composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions.

7. In step (1), the solvent is an acidic aqueous solution or a neutral aqueous solution, and the acidic aqueous solution is an aqueous acetic acid solution with a concentration of 1 to 5% wt. and / or, in step (2), the rotational speed of the high-speed shear is 1000 to 2000 r / min, and the time is 30 to 35 min. and / or, in step (3), the temperature of the crosslinking reaction is 60 to 70°C and the time is 2 to 3 hours. and / or, in step (4), the post-treatment is shape fixation, hardening, and drying, characterized in that a method for preparing composite microspheres having hygroscopic, antibacterial, and deodorizing functions according to claim 6.

8. Use of the composite microspheres having moisture-absorbing, antibacterial, and deodorizing functions as described in claim 1 in the field of preparing functional textile products.

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