Microcapsule controlled-release efficient deodorization paper diaper and preparation method thereof

Abstract

The microcapsule controlled-release efficient deodorization paper diaper comprises a deodorization surface layer, a flow guide layer, a composite core body and a bottom layer which are sequentially compounded, the deodorization surface layer is coated with deodorization antibacterial liquid containing controlled-release microcapsules, the composite core body is composed of a rapid absorption layer and a deodorization water locking layer, the rapid absorption layer and the deodorization water locking layer both contain controlled-release microcapsules, and the bottom layer is coated with deodorization antibacterial liquid containing controlled-release microcapsules. The preparation method comprises the following steps: S1, preparing quaternary ammonium salt chitosan; s2, preparing an inner core layer of the controlled-release microcapsule; the preparation method comprises the following steps: S1, preparing a shell layer, S2, preparing quaternary ammonium salt chitosan, S3, preparing amphiphilic chitosan microspheres, S4, loading a natural plant extract on the amphiphilic chitosan microspheres, S5, coating the shell layer to prepare a controlled-release microcapsule, S6, preparing a deodorization surface layer, S7, preparing a composite core body, and S8, carrying out composite molding on the paper diaper. The deodorization efficiency and durability are obviously improved, and meanwhile, the paper diaper is kept dry and comfortable.

Description

Technical Field

[0001] The invention relates to the field of diaper technology, and in particular to a microcapsule controlled-release high-efficiency deodorizing diaper and a preparation method thereof. Background Art

[0002] During the wearing process of diapers, the retention of urine or loose stools and other excreta and the action of bacteria will produce odor. Diapers absorb urine during use, and urine contains urea, uric acid, ammonia and other components. These components will decompose and produce odor under the action of bacteria. If diapers are not replaced in time, urine will be retained in the diapers for a long time, which will aggravate the generation of odor. In addition, the pH and temperature of urine will also affect the generation of odor. In addition, various additives may be added to diapers during the production process, such as plant gums and additives. These additives themselves may have a certain odor. The above two sources of odor reduce the wearing experience of diapers to a certain extent.

[0003] Based on the above situation, in the prior art, the patent number CN202410771817.2 discloses an antibacterial and deodorizing diaper, which is made of the following raw materials in parts by weight: polylactic acid: 80-100 parts; bimodal polyethylene: 15-20 parts; pore-forming agent: 20-30 parts; antibacterial dispersion: 10-20 parts; plant-based fragrance extract: 5-10 parts; coupling agent: 1-2 parts; dispersant: 2-3 parts; cross-linking agent: 3-4 parts; antioxidant: 1-1.5 parts. The diaper is made of the above raw materials. After being manufactured, it has significant antibacterial and deodorizing effects, and at the same time has excellent tensile strength and flexibility; the diaper has good water absorption performance, can quickly absorb the moisture in the diaper, and is not easy to deform, increasing the liquid holding space, and can effectively prevent the liquid on the diaper from contacting the human body. At the same time, the addition of antibacterial dispersion can play an antibacterial and bactericidal role, wherein the plant-based flavor extract is one or more of jasmine, rose, wormwood, mint, citrus and other flavor extracts; the flavor extract is in the form of essential oil or aqueous solution.

[0004] However, the antibacterial and deodorizing diapers in the above-mentioned patents still have some deficiencies when used. Specifically, although plant-based fragrance extracts and antibacterial dispersions are added to diapers to provide deodorizing and antibacterial effects, these ingredients have not undergone special encapsulation treatment in the diapers. Therefore, as time goes by and the use process proceeds, these fragrance or antibacterial ingredients tend to gradually evaporate into the air, causing the deodorizing and antibacterial effects of the diapers to gradually weaken. In addition, the plant-based fragrance extracts and antibacterial dispersions dispersed in the diapers may be affected by the external environment (such as humidity, temperature, etc.), thereby further reducing their stability and effectiveness, which not only affects the continuous deodorizing and antibacterial performance of the diapers, but may also have a negative impact on the user's wearing experience. Summary of the invention

[0005] In view of the technical defects existing in the background technology, the present invention proposes a microcapsule controlled-release high-efficiency deodorizing diaper and a preparation method thereof, which solves the above technical problems and meets the actual needs. The specific technical solution is as follows: A microcapsule controlled-release high-efficiency deodorizing diaper comprises a deodorizing surface layer, a diversion layer, a composite core and a bottom layer which are compounded in sequence, wherein the surface of the deodorizing surface layer is coated with a deodorizing antibacterial liquid, the composite core comprises a rapid absorption layer and a deodorizing water-locking layer, the deodorizing antibacterial liquid and the deodorizing water-locking layer both contain controlled-release microcapsules, the controlled-release microcapsules comprise an inner core layer and an outer shell layer, the inner core layer is a porous chitosan material, a natural plant extract with a deodorizing effect is coated in the inner core layer, and the outer shell layer is composed of a mixture of quaternary ammonium salt chitosan, gelatin and polyvinyl alcohol.

[0006] The deodorant and antibacterial liquid comprises the following components by weight: 5-10 parts of controlled-release microcapsules, 5-10 parts of quaternary ammonium salt chitosan, 1-5 parts of hyaluronic acid, 1-5 parts of glycerol, and 50-70 parts of deionized water. The weight proportions of the components of the outer shell layer are: 5-10 parts of quaternary ammonium salt chitosan, 5-10 parts of gelatin and 50-60 parts of polyvinyl alcohol, and 50-60 parts of deionized water.

[0007] Furthermore, the natural plant extract is any one of tea tree essential oil or lavender essential oil.

[0008] Furthermore, the deodorizing and water-locking layer is composed of a first absorbent and an activated carbon non-woven fabric coated on the surface of the absorbent, and the components of the first absorbent include, by weight percentage: 30-35 parts of a polymer resin, 10-15 parts of controlled-release microcapsules, and 55-65 parts of fluff pulp. The rapid absorption layer is composed of a second absorbent and a coated woven fabric coated on the surface of the absorbent, and the components of the second absorbent include, by weight percentage: 25-30 parts of a highly absorbent resin and 50-60 parts of fluff pulp.

[0009] A method for preparing microcapsule controlled-release high-efficiency deodorizing diapers comprises the following steps: S1. Prepare quaternary ammonium salt chitosan. Heat chitosan I and dissolve it in isopropanol. Adjust the pH (pH=8-9). Then add a certain amount of 2,3-epoxypropyltrimethylammonium chloride. Stir and react at a constant temperature of 60-90℃ for 6-24 hours. After the reaction is completed, dialyze for 2-3 days to remove unreacted 2,3-epoxypropyltrimethylammonium chloride. Then, vacuum freeze-dry for 48 hours to obtain chitosan quaternary ammonium salt.

[0010] S2. Prepare the inner core layer of the controlled-release microcapsule. Add a certain amount of chitosan II and polyvinyl alcohol I into a 1wt.% acetic acid aqueous solution, heat to 75-80°C, stir and dissolve evenly to obtain a mixed solution, spray-dry the mixed solution at 105-115°C to obtain a mixed powder, add the mixed powder into a 0.5% NaOH aqueous solution, heat to 75-80°C, stir and wash to dissolve and remove the PVA component, centrifuge and separate the solid phase, wash with pure water until neutral, and obtain porous chitosan microspheres.

[0011] S3. Add porous chitosan microspheres to isopropanol solution, then slowly drop epoxy long-chain alkyl quaternary ammonium salt while stirring until the mixture is evenly stirred, then slowly drop sodium hydroxide solution while stirring. After the addition is complete, keep the mixture stirring in a 50°C water bath for 24 hours. After the product is dialyzed with deionized water for 3 days, lyophilize to obtain amphiphilic chitosan microspheres.

[0012] S4. Soak the amphiphilic chitosan in an ethanol solution containing 5% natural plant extracts, ultrasonicate for 24 hours, and filter to obtain composite amphiphilic chitosan microspheres.

[0013] S5, preparing the outer core layer of the controlled release microcapsule, dissolving 5 parts of the quaternary ammonium salt chitosan, 5 parts of gelatin and 60 parts of polyvinyl alcohol II in 60 parts of deionized water in step S1 to obtain an outer core layer material liquid, then adding the composite amphiphilic chitosan microspheres in step S4 to the outer core layer material liquid, stirring evenly, and then centrifuging to obtain a solid, and drying the solid at room temperature to obtain a controlled release microcapsule, wherein the molecular weight of the polyvinyl alcohol II is 2000, and the degree of alcoholysis is 80-90%.

[0014] S6. Mix 5 parts of controlled-release microcapsules, 5 parts of quaternary ammonium salt chitosan, 1 part of hyaluronic acid, 1 part of glycerol, and 70 parts of ethanol to obtain a deodorizing and antibacterial liquid, and then apply the deodorizing and antibacterial liquid on the surface layer to obtain a deodorizing surface layer.

[0015] S7. Evenly mix 35 parts of polymer resin, 15 parts of controlled release microcapsules, and 65 parts of fluff pulp, and then use core molding equipment to form a first absorbent body, and coat the outer layer of the first absorbent body with activated carbon non-woven fabric to obtain a deodorizing and water-locking layer. Evenly mix 30 parts of super absorbent resin and 60 parts of fluff pulp, and then use core molding equipment to form a second absorbent body, and wrap the outer layer of the second absorbent body with non-woven fabric to obtain a quick absorption layer. The quick absorption layer is compounded on the upper surface of the deodorizing and water-locking layer by hot melt adhesive to obtain a composite core.

[0016] S8, compounding the deodorizing surface layer, the guide layer, the composite core and the bottom layer in sequence to obtain a diaper.

[0017] Furthermore, in step S1, the mass ratio of 2,3-epoxypropyltrimethylammonium chloride to chitosan I is 3:1.2, the reaction time is 10 h, the reaction temperature is 75° C., and the molecular weight of chitosan I is 3000.

[0018] Further, in step S2, 2.0 g of chitosan II and 1.6 g of polyvinyl alcohol I are added to 100 mL of 1 wt.% acetic acid aqueous solution, heated to 75-80° C., stirred and dissolved evenly to obtain a mixed solution, the mixed solution is spray-dried at 105-115° C. to obtain a mixed powder, the mixed powder is added to a NaOH aqueous solution with a mass concentration of 0.5%, heated to 75-80° C., stirred and washed, the polyvinyl alcohol is dissolved and removed, the solid phase is separated by centrifugation, and washed with pure water until neutral to obtain porous chitosan microspheres, wherein the molecular weight of the chitosan II is 40-50 KDa, and the molecular weight of the polyvinyl alcohol I is 5000.

[0019] Further, in step S3, 1 g of porous chitosan microspheres is added to 20 mL of 50% isopropanol solution, and then epoxy long-chain alkyl quaternary ammonium salt is slowly added dropwise while stirring until the mixture is evenly stirred, and then 2.5 mL of 40% sodium hydroxide solution is slowly added dropwise while stirring. After the addition is completed, the mixture is stirred in a 50°C water bath for 24 hours. After the product is dialyzed with deionized water for 2 days, it is freeze-dried to obtain amphiphilic chitosan microspheres, wherein the mass ratio of the epoxy long-chain alkyl quaternary ammonium salt to the porous chitosan microspheres is 1:2, and the epoxy long-chain alkyl quaternary ammonium salt is 2-epoxypropyl dodecyl dimethyl quaternary ammonium salt.

[0020] The beneficial effects of the present invention are: Through the controlled-release microcapsule technology, natural plant extracts with deodorizing effect are encapsulated in the inner core of the porous chitosan material, and then wrapped with an outer shell layer, so as to realize the controlled release of deodorizing ingredients, thereby improving the deodorizing efficiency and prolonging the duration of the deodorizing effect. The quaternary ammonium salt chitosan in the outer shell layer itself has an antibacterial effect, and synergizes with the natural plant extract in the inner core to enhance the antibacterial performance of the diaper. The composite core design includes a fast absorption layer and a deodorizing and water-locking layer. The fast absorption layer can quickly absorb urine, while the deodorizing and water-locking layer effectively locks and absorbs the odor components in the urine through the synergistic effect of activated carbon non-woven fabric and controlled-release microcapsules, while keeping the surface of the diaper dry. DETAILED DESCRIPTION

[0021] The implementation mode of the present invention is described below in conjunction with relevant embodiments. The implementation mode of the present invention is not limited to the following embodiments, and the present invention relates to relevant necessary components in the technical field, which should be regarded as the known technology in the technical field and can be known and mastered by the technical personnel in the technical field.

[0022] A microcapsule controlled-release high-efficiency deodorizing diaper, comprising a deodorizing surface layer, a diversion layer, a composite core body and a bottom layer which are compounded in sequence, wherein the surface of the deodorizing surface layer is coated with a deodorizing antibacterial liquid, the composite core body comprises a rapid absorption layer and a deodorizing water-locking layer, the deodorizing antibacterial liquid and the deodorizing water-locking layer both contain controlled-release microcapsules, the controlled-release microcapsules comprise an inner core layer and an outer shell layer, the inner core layer is a porous chitosan material, a natural plant extract having a deodorizing effect is coated in the inner core layer, and the outer shell layer is composed of a mixture of quaternary ammonium salt chitosan, gelatin and polyvinyl alcohol; The deodorant and antibacterial liquid comprises the following components by weight: 5-10 parts of controlled-release microcapsules, 5-10 parts of quaternary ammonium salt chitosan, 1-5 parts of hyaluronic acid, 1-5 parts of glycerol, and 50-70 parts of deionized water. The weight proportions of the components of the outer shell layer are: 5-10 parts of quaternary ammonium salt chitosan, 5-10 parts of gelatin and 50-60 parts of polyvinyl alcohol, and 50-60 parts of deionized water.

[0023] In the structure of the controlled-release microcapsule of the present invention, the outer shell layer is composed of a mixture of quaternary ammonium salt chitosan, gelatin and polyvinyl alcohol. The above materials have good water solubility. When the diaper encounters urine, the outer shell layer can be quickly dissolved, so that the natural plant extract with deodorizing effect (such as tea tree essential oil or lavender essential oil) in the inner core layer can be quickly released, quickly neutralize the odor components in urine, and achieve a quick-response deodorizing effect. At the same time, the porous structure of the inner core of the controlled-release microcapsule can store a certain amount of natural plant extracts, so that the natural plant extracts can be continuously and slowly released, which prolongs the duration of the deodorizing effect and ensures that the diaper can still maintain good deodorizing performance during long-term use.

[0024] As one of the main components of the outer shell, quaternary ammonium chitosan itself has excellent antibacterial properties and can effectively inhibit the growth and reproduction of bacteria, reducing the odor and harmful substances produced by bacteria in urine. The natural plant extracts in the inner core layer also have certain antibacterial effects, and synergize with the quaternary ammonium chitosan in the outer shell to enhance the antibacterial properties of the diaper and provide a safer and healthier wearing environment for babies.

[0025] Controlled-release microcapsules are added to the deodorizing surface layer and the composite core respectively, which can effectively enhance the comprehensive performance of diapers in deodorization and antibacterial properties, thereby providing a good wearing experience. In addition, the addition of hyaluronic acid and glycerin to the antibacterial and deodorizing surface layer can moisturize the skin, reduce the irritation and damage of urine to the skin, and protect the baby's skin.

[0026] The composite core structure of the present invention includes a fast-absorbing layer and a deodorizing and water-locking layer, so that the diaper has excellent moisture absorption and water retention. The fast-absorbing layer can quickly absorb urine, while the deodorizing and water-locking layer effectively locks and absorbs excess moisture in urine and neutralizes odors through the synergistic effect of activated carbon non-woven fabric and controlled-release microcapsules, thereby keeping the surface of the diaper dry and clean.

[0027] As one of the preferred embodiments of the present invention, the natural plant extract is any one of tea tree essential oil or lavender essential oil.

[0028] Natural plant extracts (tea tree essential oil or lavender essential oil) play an important role in antibacterial and odor neutralization in microcapsule controlled-release high-efficiency deodorant diapers. Through the design of controlled-release microcapsules, continuous and effective release is achieved, which not only inhibits the growth and reproduction of bacteria, but also neutralizes the odor components in urine.

[0029] In terms of antibacterial properties, tea tree essential oil and lavender essential oil both have natural antibacterial properties. Tea tree essential oil contains a variety of ingredients with antibacterial activity, such as terpinen-4-ol, which can destroy the cell membrane of bacteria and inhibit the growth and reproduction of bacteria, thereby reducing the odor and harmful substances produced by bacteria in urine. Lavender essential oil also has antibacterial effects. The ingredients it contains, such as linalool and linalyl acetate, have inhibitory effects on a variety of bacteria and help keep the inside of diapers clean and hygienic.

[0030] In terms of neutralizing odors, tea tree essential oil and lavender essential oil both have a refreshing aroma. These aroma components can react with the odor components in urine and neutralize the odor through chemical or physical means, so that the diapers maintain a fresh and pleasant smell during use. In addition, these natural plant extracts can also release fragrance into the air through their volatile characteristics, thereby increasing the aroma of the diapers to enhance the user's wearing experience.

[0031] As one of the preferred embodiments of the present invention, the deodorizing and water-locking layer is composed of a first absorbent and an activated carbon non-woven fabric coated on the surface of the absorbent, and the components of the first absorbent include, by weight percentage: 30-35 parts of polymer resin, 10-15 parts of controlled-release microcapsules, and 55-65 parts of fluff pulp. The rapid absorption layer is composed of a second absorbent and a coated woven fabric coated on the surface of the absorbent, and the components of the second absorbent include, by weight percentage: 25-30 parts of super absorbent resin and 50-60 parts of fluff pulp.

[0032] The composite core of the present invention is a double-core structure, including a deodorizing and water-locking layer and a fast-absorbing layer. The deodorizing and water-locking layer and the fast-absorbing layer respectively use different absorbent materials, so that the diaper can quickly absorb and lock urine and keep the surface dry. The polymer resin and controlled-release microcapsules in the deodorizing and water-locking layer have excellent moisture absorption properties, can absorb and lock a large amount of urine, and prevent reverse osmosis. The highly absorbent resin in the fast-absorbing layer can quickly absorb urine, further improving the moisture absorption speed of the diaper.

[0033] Controlled-release microcapsules are an important component of the dual-core structure. The inner core layer is coated with natural plant extracts with antibacterial effects (such as tea tree essential oil or lavender essential oil). Under the action of controlled-release microcapsules, natural plant extracts can be continuously released, effectively inhibiting the growth and reproduction of bacteria and reducing the odor and harmful substances produced by bacteria in urine. The natural plant extracts in the controlled-release microcapsules not only have antibacterial effects, but can also neutralize the odor components in urine, so that the diapers maintain a fresh and pleasant smell during use.

[0034] The activated carbon non-woven fabric coating of the deodorizing and water-locking layer further enhances the deodorizing effect. The activated carbon in the activated carbon non-woven fabric has a strong adsorption capacity, which can adsorb and lock odor molecules to prevent them from spreading. The polymer resin has good hygroscopicity and water retention, and can absorb and lock a large amount of urine.

[0035] A method for preparing microcapsule controlled-release high-efficiency deodorizing diapers comprises the following steps: S1. Prepare quaternary ammonium salt chitosan. Heat chitosan I and dissolve it in isopropanol. Adjust the pH (pH=8-9). Then add a certain amount of 2,3-epoxypropyltrimethylammonium chloride. Stir and react at a constant temperature of 60-90°C for 6-24 hours. After the reaction is completed, dialyze for 2-3 days to remove unreacted 2,3-epoxypropyltrimethylammonium chloride. Then, freeze-dry in vacuum for 48 hours to obtain chitosan quaternary ammonium salt. S2, preparing the inner core layer of the controlled-release microcapsule, adding a certain amount of chitosan II and polyvinyl alcohol I to a 1wt.% acetic acid aqueous solution, heating to 75-80°C, stirring and dissolving to obtain a mixed solution, spray drying the mixed solution at a temperature of 105-115°C to obtain a mixed powder, adding the mixed powder to a 0.5% NaOH aqueous solution, heating to 75-80°C, stirring and washing to dissolve and remove the PVA component, centrifuging and separating the solid phase, and washing with pure water until neutral to obtain porous chitosan microspheres; S3. Add porous chitosan microspheres to isopropanol solution, then slowly drop epoxy long-chain alkyl quaternary ammonium salt while stirring until the mixture is evenly stirred, then slowly drop sodium hydroxide solution while stirring. After the addition is complete, keep the mixture stirring in a 50°C water bath for 24 hours. After the product is dialyzed with deionized water for 3 days, lyophilize to obtain amphiphilic chitosan microspheres.

[0036] S4. Soak the amphiphilic chitosan in an ethanol solution containing 5% natural plant extracts, ultrasonicate for 24 hours, and filter to obtain composite amphiphilic chitosan microspheres.

[0037] S5, preparing the outer core layer of the controlled release microcapsule, dissolving 5 parts of the quaternary ammonium salt chitosan, 5 parts of gelatin and 60 parts of polyvinyl alcohol II in 60 parts of deionized water in step S1 to obtain an outer core layer material liquid, then adding the composite amphiphilic chitosan microspheres in step S4 to the outer core layer material liquid, stirring evenly, and then centrifuging to obtain a solid, and drying the solid at room temperature to obtain a controlled release microcapsule, wherein the molecular weight of the polyvinyl alcohol II is 2000, and the degree of alcoholysis is 80-90%.

[0038] S6, 5 parts of controlled release microcapsules, 5 parts of quaternary ammonium salt chitosan, 1 part of hyaluronic acid, 1 part of glycerol, and 70 parts of ethanol are mixed to obtain a deodorant antibacterial liquid, and then the deodorant antibacterial liquid is applied on the surface of the surface layer to obtain a deodorant surface layer. S7. Evenly mix 35 parts of polymer resin, 15 parts of controlled release microcapsules, and 65 parts of fluff pulp, and then use core molding equipment to form a first absorbent body, and coat the outer layer of the first absorbent body with activated carbon non-woven fabric to obtain a deodorizing and water-locking layer. Evenly mix 30 parts of super absorbent resin and 60 parts of fluff pulp, and then use core molding equipment to form a second absorbent body, and wrap the outer layer of the second absorbent body with non-woven fabric to obtain a quick absorption layer. The quick absorption layer is compounded on the upper surface of the deodorizing and water-locking layer by hot melt adhesive to obtain a composite core.

[0039] S8, compounding the deodorizing surface layer, the guide layer, the composite core and the bottom layer in sequence to obtain a diaper.

[0040] In terms of the preparation method, the present invention firstly prepares porous chitosan microspheres from chitosan and polyvinyl alcohol by spray drying and chemical modification, and utilizes the solubility of polyvinyl alcohol in sodium hydroxide solution to form chitosan microspheres with a porous structure, thereby providing a carrier for the subsequent coating of natural plant extracts.

[0041] Next, the porous chitosan microspheres are immersed in an ethanol solution containing natural plant extracts, and the extracts are evenly infiltrated into the microspheres through ultrasonic treatment. Then, the composite amphiphilic chitosan microspheres are obtained by filtration. The deodorizing and antibacterial properties of the natural plant extracts are fixed inside the microspheres to achieve a controlled release effect.

[0042] Finally, the composite amphiphilic chitosan microspheres are added to the outer shell material liquid composed of quaternary ammonium chitosan, gelatin and polyvinyl alcohol, and the solid is obtained by stirring evenly and then centrifuging. The solid is then dried at room temperature to obtain controlled-release microcapsules. The water solubility of polyvinyl alcohol is utilized to form an outer shell layer that can quickly dissolve in water. This allows the controlled-release microcapsules to quickly release the natural extract in the inner core layer when encountering urine, thereby achieving the antibacterial and deodorizing effects.

[0043] The invention obtains a deodorizing and antibacterial liquid by mixing controlled-release microcapsules, quaternary ammonium salt chitosan, hyaluronic acid and glycerol in a certain proportion, adding deionized water for mixing, and then coating the liquid on a surface layer to obtain a deodorizing surface layer, thereby effectively utilizing the synergistic effect of the components, wherein the controlled-release microcapsules provide controlled-release deodorizing and antibacterial effects, the quaternary ammonium salt chitosan enhances antibacterial properties, and the hyaluronic acid and glycerol provide moisturizing and comfort.

[0044] The present invention prepares a first absorbent body by uniformly mixing a polymer resin, a controlled-release microcapsule and a fluff pulp, and then using a core-forming device to form the first absorbent body. The first absorbent body is then coated with an activated carbon non-woven fabric on the outer layer to obtain a deodorizing and water-locking layer. The hygroscopicity and water-retaining properties of the polymer resin, the deodorizing and antibacterial properties of the controlled-release microcapsules, and the adsorptive properties of the activated carbon non-woven fabric are used to achieve a deodorizing and water-locking effect. The highly absorbent resin and the fluff pulp are uniformly mixed, and then using a core-forming device to form the second absorbent body. The second absorbent body is then coated with a non-woven fabric on the outer layer to obtain a quick-absorbing layer. The quick-absorbing and water-retaining properties of the highly absorbent resin, and the air permeability and softness of the non-woven fabric are used to achieve a quick-absorbing and dry-keeping effect.

[0045] As one of the preferred embodiments of the present invention, in step S1, the mass ratio of 2,3-epoxypropyltrimethylammonium chloride to chitosan I is 3:1.2, the reaction time is 10 h, the reaction temperature is 75° C., and the molecular weight of chitosan I is 3000.

[0046] In step S1, chitosan I is heated and dissolved in isopropanol. Isopropanol is used as a solvent. Under alkaline conditions of pH 8 to 9, the amino groups (-NH 2 ) is more likely to undergo nucleophilic reactions and ring-opening reactions with epoxy groups, 2,3-epoxypropyltrimethylammonium chloride. This is a quaternary ammonium salt compound containing epoxy groups, whose epoxy groups can undergo ring-opening reactions with the amino groups on the chitosan molecules to form covalent bonds. At the same time, the introduction of quaternary ammonium salt groups gives chitosan cationic properties and enhances its antibacterial properties.

[0047] As one of the preferred embodiments of the present invention, in step S2, 2.0 g of chitosan II and 1.6 g of polyvinyl alcohol I are added to 100 mL of 1 wt.% acetic acid aqueous solution, heated to 75-80° C., stirred and dissolved evenly to obtain a mixed solution, and the mixed solution is spray-dried at a temperature of 105-115° C. to obtain a mixed powder, and the mixed powder is added to a NaOH aqueous solution with a mass concentration of 0.5%, heated to 75-80° C., stirred and washed, the polyvinyl alcohol is dissolved and removed, the solid phase is separated by centrifugation, and washed with pure water until neutral to obtain porous chitosan microspheres, wherein the molecular weight of the chitosan II is 40-50 KDa, and the molecular weight of the polyvinyl alcohol I is 5000.

[0048] In step S2, chitosan II and polyvinyl alcohol I are selected as main raw materials. Chitosan is a natural polysaccharide with good biocompatibility and degradability, while polyvinyl alcohol is a water-soluble polymer. The two can be combined to form a stable mixed solution. Chitosan II and polyvinyl alcohol I are added to an acetic acid aqueous solution, heated to 75-80°C and stirred to fully dissolve and mix the two. Then the mixed solution is sprayed into hot air through a sprayer. The hot air is used to dry the solution to evaporate rapidly to form tiny particles to obtain a mixed powder containing chitosan and polyvinyl alcohol. The mixed powder is added to a NaOH aqueous solution with a mass concentration of 0.5%. NaOH can react with polyvinyl alcohol to dissolve it, while chitosan remains stable under this condition. It is heated to 75-80°C and stirred to fully dissolve and wash away the polyvinyl alcohol. The solid phase (i.e., porous chitosan microspheres) is separated from the liquid phase by centrifugation, and then washed with pure water until neutral to remove residual NaOH and other impurities.

[0049] The molecular weight of chitosan II is 40-50KDa, and the molecular weight of polyvinyl alcohol I is 5000. Chitosan with a higher molecular weight of chitosan II can form a more stable microsphere structure, but has poor solubility; polyvinyl alcohol with a lower molecular weight of polyvinyl alcohol I is easier to remove, thereby forming a porous structure on the chitosan sphere.

[0050] As one of the preferred embodiments of the present invention, in step S3, 1 g of porous chitosan microspheres is added to 20 mL of 50% isopropanol solution, and then epoxy long-chain alkyl quaternary ammonium salt is slowly added dropwise while stirring until the mixture is evenly stirred, and then 2.5 mL of 40% sodium hydroxide solution is slowly added dropwise while stirring. After the addition is completed, the mixture is stirred in a 50°C water bath for 24 hours. After the product is dialyzed with deionized water for 2 days, it is freeze-dried to obtain amphiphilic chitosan microspheres, wherein the mass ratio of the epoxy long-chain alkyl quaternary ammonium salt to the porous chitosan microspheres is 1:2, and the epoxy long-chain alkyl quaternary ammonium salt is 2-epoxypropyl dodecyl dimethyl quaternary ammonium salt.

[0051] In step S3, the epoxy long-chain alkyl quaternary ammonium salt molecule contains an epoxy group, which is easy to undergo a ring-opening reaction under alkaline conditions (such as in the presence of sodium hydroxide solution). When the epoxy group contacts the active groups such as hydroxyl or amino groups on the porous chitosan microspheres, a ring-opening addition reaction will occur to form a covalent bond connection. After the ring-opening reaction, the epoxy long-chain alkyl quaternary ammonium salt introduces its long-chain alkyl and quaternary ammonium salt groups into the chitosan microspheres. The presence of the long-chain alkyl group significantly increases the lipophilicity of the chitosan microspheres, which makes the modified chitosan microspheres better compatible with oil-soluble or hydrophobic substances, and facilitates the subsequent S4 step (i.e., immersing in an ethanol solution containing natural plant extracts), thereby facilitating the amphiphilic chitosan microspheres to better adsorb and load the natural plant extracts, and helping to effectively fix the natural plant extracts with deodorizing effects in the controlled-release microcapsules during the preparation of diapers.

[0052] Example 1

[0053] A method for preparing microcapsule controlled-release high-efficiency deodorizing diapers comprises the following steps: S1. Prepare quaternary ammonium salt chitosan. Heat and dissolve chitosan I (molecular weight 3000) in isopropanol, adjust pH to 8-9, then add a certain amount of 2,3-epoxypropyltrimethylammonium chloride, and react at 75°C with constant temperature stirring for 10 h. After the reaction is completed, dialyze for 2-3 d to remove unreacted 2,3-epoxypropyltrimethylammonium chloride, and then vacuum freeze-dry for 48 h to obtain chitosan quaternary ammonium salt. The mass ratio of 2,3-epoxypropyltrimethylammonium chloride to chitosan I is 3:1.2.

[0054] S2. Add 2.0 g of chitosan II (molecular weight 40-50 KDa) and 1.6 g of polyvinyl alcohol I (molecular weight 5000) into 100 mL of 1 wt.% acetic acid aqueous solution, heat to 75-80°C, stir and dissolve evenly to obtain a mixed solution, spray dry the mixed solution at 105-115°C to obtain a mixed powder with a particle size of 50-100 μm, add the mixed powder into a NaOH aqueous solution with a mass concentration of 0.5%, heat to 75-80°C, stir and wash, dissolve and remove the polyvinyl alcohol, centrifuge and separate the solid phase, wash with pure water until neutral, and obtain porous chitosan microspheres.

[0055] S3, take 1g of porous chitosan microspheres and add it to 20mL of 50% isopropanol solution, then slowly add epoxy long-chain alkyl quaternary ammonium salt, stirring while adding, until the mixture is evenly stirred, then slowly add 2.5mL of 40% sodium hydroxide solution, stirring while adding, after the addition is completed, keep the mixture stirring in a 50℃ water bath for 24h, dialyze the product with deionized water for 2 days, and then freeze-dry to obtain amphiphilic chitosan microspheres, the mass ratio of the epoxy long-chain alkyl quaternary ammonium salt to the porous chitosan microspheres is 1:2, and the epoxy long-chain alkyl quaternary ammonium salt is 2-epoxypropyl dodecyl dimethyl quaternary ammonium salt.

[0056] S4. Soak the amphiphilic chitosan in an ethanol solution containing 5% natural plant extract (tea tree essential oil or lavender essential oil), ultrasonicate for 24 hours, and filter to obtain composite amphiphilic chitosan microspheres.

[0057] S5. Prepare the outer core layer of the controlled-release microcapsule. Dissolve 5 parts of the quaternary ammonium salt chitosan and 5 parts of gelatin and 60 parts of polyvinyl alcohol II (molecular weight of 2000 and degree of alcoholysis of 80-90%) in 60 parts of deionized water to obtain an outer core layer liquid. Then add the composite amphiphilic chitosan microspheres in step S4 to the outer core layer liquid, stir evenly, and then centrifuge to obtain a solid. Dry the solid at room temperature to obtain a controlled-release microcapsule.

[0058] S6. Mix 5 parts of controlled-release microcapsules, 5 parts of quaternary ammonium salt chitosan, 1 part of hyaluronic acid, 1 part of glycerol, and 70 parts of ethanol to obtain a deodorizing and antibacterial liquid, and then apply the deodorizing and antibacterial liquid on the surface layer in an amount of 5 gsm, and dry to obtain a deodorizing surface layer.

[0059] S7. Evenly mix 35 parts of polymer resin, 15 parts of controlled release microcapsules, and 65 parts of fluff pulp, and then use core molding equipment to form a first absorbent body, and coat the outer layer of the first absorbent body with activated carbon non-woven fabric to obtain a deodorizing and water-locking layer. Evenly mix 30 parts of super absorbent resin and 60 parts of fluff pulp, and then use core molding equipment to form a second absorbent body, and wrap the outer layer of the second absorbent body with non-woven fabric to obtain a quick absorption layer. The quick absorption layer is compounded on the upper surface of the deodorizing and water-locking layer by hot melt adhesive to obtain a composite core.

[0060] S8, compounding the deodorizing surface layer, the guide layer, the composite core and the bottom layer in sequence to obtain a diaper.

[0061] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, no quaternary ammonium salt chitosan is added in step S5.

[0062] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, no quaternary ammonium salt chitosan is added in step S6.

[0063] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, no controlled-release microcapsules are added in step S6.

[0064] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, no controlled-release microcapsules are added in step S7.

[0065] The antibacterial performance of the above-mentioned Example 1 and Comparative Examples 1-4 was tested respectively, the solubility of the outer shell layer of the controlled release microcapsules prepared in Example 1 and Comparative Examples 1-4 was tested, and the deodorizing ability of Example 1 and Comparative Examples 1-4 was evaluated. The results are shown in the following table: The deodorizing ability of Example 1 and Comparative Examples 1-4 was evaluated by the following method: 100 mL of 0.5% ammonia water was poured on the corresponding diaper samples of Example 1 and Comparative Examples 1-4 to wet the diapers to simulate the diapers after a baby urinates. Then the experimenter smelled the odor intensity of the ammonia, and the odor intensity was represented by 6 levels, namely: 0-no odor; 1-barely perceptible odor; 2-weak odor; 3-easily perceptible odor; 4-strong odor; 5-very strong odor.

[0066]

[0067] In terms of antibacterial performance, Example 1 has a complete addition of quaternary ammonium chitosan and controlled-release microcapsules, and the antibacterial rates against Escherichia coli and Staphylococcus aureus reached 97.2% and 95.6%, respectively, showing strong antibacterial performance. In Comparative Example 1, quaternary ammonium chitosan was not added to the outer core layer liquid, resulting in a decrease in the antibacterial rates of Escherichia coli and Staphylococcus aureus, but still maintained at a high level (94.8% and 92.3%), indicating that quaternary ammonium chitosan has a certain effect on enhancing the antibacterial performance. In Comparative Examples 2 and 3, quaternary ammonium chitosan and controlled-release microcapsules were omitted in the preparation process of the deodorizing antibacterial liquid, and the antibacterial performance further decreased. After the controlled-release microcapsules were omitted in Comparative Example 3, the antibacterial rate decreased more significantly, indicating that the controlled-release microcapsules played a major role in the antibacterial performance. In Comparative Example 4, no controlled-release microcapsules were added during the preparation of the composite core, and the antibacterial performance decreased the most, indicating that the controlled-release microcapsules play a key role in the overall antibacterial performance of the diaper.

[0068] In terms of water solubility of the controlled-release microcapsules, the rupture time and dissolution time of the shell layer of the controlled-release microcapsules in Example 1 and Comparative Examples 2-4 are relatively stable. The rupture time and dissolution time of the shell layer in Comparative Example 1 are slightly shortened because the lack of quaternary ammonium salt chitosan in the shell layer material liquid leads to an accelerated dissolution rate of the shell layer.

[0069] In terms of the deodorizing performance of the diapers, Example 1 adds controlled-release microcapsules to both the deodorizing surface layer and the composite core, indicating that the dual distribution of microcapsules in the surface layer and the core can synergistically release natural plant extracts (tea tree essential oil / lavender essential oil), quickly neutralize odor components such as ammonia in urine, and achieve long-term controlled release, ensuring that the deodorizing effect is lasting and stable. The deodorizing scores of Comparative Examples 1 and 2 are both 1, which is consistent with Example 1, indicating that the absence of quaternary ammonium salt chitosan has little effect on the deodorizing ability. The scores of Comparative Examples 3 and 4 are both 2, indicating that when only the surface layer or the core contains microcapsules, the deodorizing ability decreases significantly. Comparative Example 3 lacks the rapid release ability of the surface layer microcapsules and only relies on the slow release of the core microcapsules, resulting in insufficient neutralization of the initial odor. The core of Comparative Example 4 lacks the sustained release effect of the microcapsules, and the surface layer microcapsules cannot be released after the rapid release, resulting in a weakened deodorizing effect in the later stage.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A microcapsule controlled-release high-efficiency deodorizing diaper, characterized in that: The invention comprises a deodorizing surface layer, a diversion layer, a composite core body and a bottom layer which are compounded in sequence. The surface of the deodorizing surface layer is coated with a deodorizing antibacterial liquid. The composite core body comprises a quick absorption layer and a deodorizing water-locking layer. The deodorizing antibacterial liquid and the deodorizing water-locking layer both contain controlled-release microcapsules. The controlled-release microcapsules comprise an inner core layer and an outer shell layer. The inner core layer is a porous chitosan material. The inner core layer is coated with a natural plant extract having a deodorizing effect. The outer shell layer is composed of a mixture of quaternary ammonium salt chitosan, gelatin and polyvinyl alcohol. The deodorant and antibacterial liquid comprises the following components by weight: 5-10 parts of controlled-release microcapsules, 5-10 parts of quaternary ammonium salt chitosan, 1-5 parts of hyaluronic acid, 1-5 parts of glycerol, and 50-70 parts of deionized water. The weight proportions of the components of the outer shell layer are: 5-10 parts of quaternary ammonium salt chitosan, 5-10 parts of gelatin and 50-60 parts of polyvinyl alcohol, and 50-60 parts of deionized water.

2. The microcapsule controlled-release high-efficiency deodorizing diaper according to claim 1, characterized in that: The natural plant extract is any one of tea tree essential oil or lavender essential oil.

3. The microcapsule controlled-release high-efficiency deodorizing diaper according to claim 1, characterized in that: The deodorizing and water-locking layer is composed of a first absorbent and an activated carbon non-woven fabric coated on the surface of the absorbent. The components of the first absorbent include, by weight percentage, 30-35 parts of a polymer resin, 10-15 parts of controlled-release microcapsules, and 55-65 parts of fluff pulp. The rapid absorption layer is composed of a second absorbent and a coated woven fabric coated on the surface of the absorbent. The components of the second absorbent include, by weight percentage, 25-30 parts of a highly absorbent resin and 50-60 parts of fluff pulp.

4. A method for preparing a microcapsule controlled-release high-efficiency deodorizing diaper according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Prepare quaternary ammonium salt chitosan. Heat chitosan I and dissolve it in isopropanol. Adjust the pH (pH=8-9). Then add a certain amount of 2,3-epoxypropyltrimethylammonium chloride. Stir and react at a constant temperature of 60-90°C for 6-24 hours. After the reaction is completed, dialyze for 2-3 days to remove unreacted 2,3-epoxypropyltrimethylammonium chloride. Then, freeze-dry in vacuum for 48 hours to obtain chitosan quaternary ammonium salt. S2, preparing the inner core layer of the controlled-release microcapsule, adding a certain amount of chitosan II and polyvinyl alcohol I to a 1wt.% acetic acid aqueous solution, heating to 75-80°C, stirring and dissolving to obtain a mixed solution, spray drying the mixed solution at a temperature of 105-115°C to obtain a mixed powder, adding the mixed powder to a 0.5% NaOH aqueous solution, heating to 75-80°C, stirring and washing to dissolve and remove the PVA component, centrifuging and separating the solid phase, and washing with pure water until neutral to obtain porous chitosan microspheres; S3, adding porous chitosan microspheres to the isopropanol solution, and then slowly dropping epoxy long-chain alkyl quaternary ammonium salt, stirring while dropping, until the mixture is evenly stirred, and then slowly dropping sodium hydroxide solution, stirring while dropping, after the dropping is completed, the mixture is kept stirring in a 50°C water bath for 24 hours, the product is dialyzed with deionized water for 3 days, and then freeze-dried to obtain amphiphilic chitosan microspheres; S4, soaking the amphiphilic chitosan in an ethanol solution containing 5% natural plant extract, ultrasonicating for 24 hours, filtering, and obtaining composite amphiphilic chitosan microspheres; S5, dissolving 5 parts of quaternary ammonium salt chitosan, 5 parts of gelatin and 60 parts of polyvinyl alcohol II in 60 parts of deionized water in step S1 to obtain an outer core layer liquid, then adding the composite amphiphilic chitosan microspheres in step S4 to the outer core layer liquid, stirring evenly, and then centrifuging to obtain a solid, and drying the solid at room temperature to obtain a controlled release microcapsule, wherein the molecular weight of the polyvinyl alcohol II is 2000, and the degree of alcoholysis is 80% to 90%; S6, mixing 5 parts of controlled-release microcapsules, 5 parts of quaternary ammonium salt chitosan, 1 part of hyaluronic acid, 1 part of glycerol, and 70 parts of ethanol to obtain a deodorizing and antibacterial liquid, and then applying the deodorizing and antibacterial liquid on the surface layer to obtain a deodorizing surface layer; S7, 35 parts of polymer resin, 15 parts of controlled-release microcapsules, and 65 parts of fluff pulp are mixed evenly, and then a core forming device is used to form a first absorbent body, and an activated carbon non-woven fabric is coated on the outer layer of the first absorbent body to obtain a deodorizing and water-locking layer, 30 parts of superabsorbent resin and 60 parts of fluff pulp are mixed evenly, and then a core forming device is used to form a second absorbent body, and a non-woven fabric is wrapped on the outer layer of the second absorbent body to obtain a rapid absorption layer, and the rapid absorption layer is compounded on the upper surface of the deodorizing and water-locking layer by hot melt adhesive to obtain a composite core; S8, compounding the deodorizing surface layer, the guide layer, the composite core and the bottom layer in sequence to obtain a diaper.

5. The method for preparing a microcapsule controlled-release high-efficiency deodorizing diaper according to claim 4, characterized in that: In step S1, the mass ratio of 2,3-epoxypropyltrimethylammonium chloride to chitosan I is 3:1.2, the reaction time is 10 h, the reaction temperature is 75° C., and the molecular weight of chitosan I is 3000.

6. The method for preparing a microcapsule controlled-release high-efficiency deodorizing diaper according to claim 4, characterized in that: In step S2, 2.0 g of chitosan II and 1.6 g of polyvinyl alcohol I are added to 100 mL of 1 wt.% acetic acid aqueous solution, heated to 75-80° C., stirred and dissolved uniformly to obtain a mixed solution, and the mixed solution is spray-dried at a temperature of 105-115° C. to obtain a mixed powder, and the mixed powder is added to a NaOH aqueous solution with a mass concentration of 0.5%, heated to 75-80° C., stirred and washed, the polyvinyl alcohol is dissolved and removed, and the solid phase is separated by centrifugation and washed with pure water until neutral to obtain porous chitosan microspheres, wherein the molecular weight of the chitosan II is 40-50 KDa, and the molecular weight of the polyvinyl alcohol I is 5000.

7. The method for preparing a microcapsule controlled-release high-efficiency deodorizing diaper according to claim 4, characterized in that: In step S3, 1 g of porous chitosan microspheres is added to 20 mL of 50% isopropanol solution, and then epoxy long-chain alkyl quaternary ammonium salt is slowly added dropwise while stirring until the mixture is evenly stirred, and then 2.5 mL of 40% sodium hydroxide solution is slowly added dropwise while stirring. After the addition is completed, the mixture is stirred in a 50° C. water bath for 24 hours. The product is dialyzed with deionized water for 2 days and then freeze-dried to obtain amphiphilic chitosan microspheres. The mass ratio of the epoxy long-chain alkyl quaternary ammonium salt to the porous chitosan microspheres is 1:2, and the epoxy long-chain alkyl quaternary ammonium salt is 2-epoxypropyl dodecyl dimethyl quaternary ammonium salt.

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