A persistent, stable and sustained-release fragrance-releasing and antibacterial microcapsule, its preparation method and application

Abstract

The present invention belongs to the technical field of functional porous carbon microcapsule preparation, and relates to a kind of long-lasting and stable sustained-release fragrance-releasing antibacterial microcapsule and its preparation method and application; It includes the following components: porous carbon microspheres 30-60%, small molecule essential oil 10-30%, organic matrix 20-50% and inorganic salt solution 10-30%. The fragrance-releasing antibacterial microcapsule of the present invention adopts bio-based porous carbon microspheres to load natural small molecule essential oil, and realizes organic-inorganic mineralization coating on the surface of microspheres by organic matrix and inorganic salt solution, so as to improve the hardness, heat resistance and other properties of microsphere particles, and realize stable sustained release of aromatic active substances, which can last for more than 2 years.

Description

Technical Field

[0001] The invention relates to the technical field of functional porous carbon microcapsule preparation, in particular to a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule and a preparation method and application thereof. Background Art

[0002] Traditional wood-based panels have long been criticized for formaldehyde emissions from adhesives, TVOC (total volatile organic compound) pollution, and odor. Although low-formaldehyde production has been achieved through technologies such as formaldehyde-free adhesives and formaldehyde scavengers, consumers' pursuit of natural health benefits continues to drive the industry's transformation towards higher value-added products. Currently, with the increasing demand for indoor environmental health and safety, the demand for antibacterial and fragrance-releasing functional wood-based panels is becoming increasingly prominent.

[0003] Natural plant extracts, thanks to their natural antibacterial properties (e.g., mugwort essential oil has an inhibition rate of >99% against Escherichia coli and Staphylococcus aureus) and fragrance-releasing properties (lasting for months), have become core functional carriers. However, the volatility and heat sensitivity of plant extracts result in poor stability and easy loss of active ingredients in traditional direct addition methods, limiting their application. Microencapsulation technology, which isolates active ingredients through a core-shell structure for sustained release, is currently widely used for encapsulating traditional Chinese medicine extracts (such as mugwort and isatis root) and has expanded into water-based coatings, sprays, and other fields.

[0004] In the manufacture of artificial boards, adding fragrance-releasing antibacterial microcapsules to adhesives can give the boards antibacterial (inhibit the growth of bacteria inside and outside the boards) and fragrance-releasing (purify odor) functions; for example, Guangdong Aigao Smart Home Co., Ltd. has successfully developed "Aixiang Board" that meets the LY / T 3230-2020 standard through the addition of Chinese herbal medicine powder and the compounding technology of essential oil microcapsules, achieving TVOC release and high-efficiency antibacterial properties; the Moganshan Plant Source Fragrance-Releasing Board developed by Zhejiang Shenghua Yunfeng Moganshan Co., Ltd. uses fragrance-locking technology to retain the natural fragrance of lavender. After 5,000 washes, the antibacterial rate is still >99.99%, and the TVOC release concentration meets the Level I standard. It also has health functions such as sleep aid and analgesia.

[0005] The high temperatures, high pressures, and acidic and alkaline environments experienced during wood-based panel processing can easily cause the wall materials of traditional microcapsules to collapse, resulting in the instantaneous release or dissociation of active ingredients, making it difficult to achieve a lasting effect. For example, while Chinese patent CN112176451 A utilizes a double-walled microcapsule structure (an inner layer of β-cyclodextrin and an outer layer of porous starch), effectively reducing the loss of encapsulated substances, the capsule wall still suffers from insufficient pressure and heat resistance.

[0006] Existing technologies face three major challenges: first, the microcapsule shell material has low mechanical strength, making it difficult to withstand processing stress; second, poor thermal stability, making it prone to failure at high temperatures; and third, insufficient sustained-release efficiency, failing to meet long-term functional requirements. A single organic or inorganic shell material struggles to achieve a balanced performance, and both materials and processes require further improvement. Summary of the Invention

[0007] One purpose of the present invention is to provide a long-lasting, stable and sustained-release aroma-releasing antibacterial porous carbon microsphere to solve the problem that existing microcapsules are not resistant to pressure and high temperature. The microspheres are loaded with small molecule essential oils and organic-inorganic mineralized coatings are achieved on the surface through an organic matrix and an inorganic salt solution to improve the hardness, heat resistance, corrosion resistance and other properties of the microcapsules, while also having a long-lasting, stable and sustained-release of aroma-releasing antibacterial active substances. The microcapsules can be suitable for use in artificial board adhesive systems.

[0008] The second object of the present invention is to provide a method for preparing long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules.

[0009] The third object of the present invention is to provide a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule for use in the preparation process of artificial board adhesives or paint films.

[0010] In order to achieve the first object of the invention, the present invention can be implemented by the following technical solution: a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule, which comprises the following components in percentage by mass:

[0011] Porous carbon microspheres 30-60%, small molecule essential oil 10-30%, organic matrix 20-50% and inorganic salt solution 10-30%.

[0012] The beneficial effects of adopting the above technical solution are as follows: (1) The present invention adopts bio-based porous carbon microspheres to load natural small molecule essential oils, and realizes organic-inorganic mineralization coating on the surface of the microspheres through an organic matrix and an inorganic salt solution to improve the hardness, heat resistance and other properties of the microsphere particles, thereby achieving stable sustained release of aromatic active substances for more than 2 years.

[0013] (2) The present invention uses natural plant essential oils as fragrance-releasing and antibacterial active substances, and self-assembles them into porous microspheres through plant-derived or animal-derived fibers, and then obtains porous carbon microsphere adsorption carriers through hydrothermal carbonization-activation. Due to the high hardness, porosity, and high specific surface area of the porous carbon microspheres, they can load more essential oil active substances and provide mechanical strength during the hot pressing process. At the same time, the thermal conductivity of carbon is low, and it can play a role in high-temperature protection of the biologically active components loaded inside it under short-term high-temperature conditions during the material production process. Then, polysaccharides or proteins are used. The organic matrix is coated, and finally an inorganic salt solution is introduced into the matrix to form an organic-inorganic mineral layer on the surface of the microspheres. On the one hand, the mineral layer containing inorganic ions can play a synergistic antiviral effect. At the same time, the mineral layer with hardness, heat resistance and acid and alkali resistance further improves the physical and mechanical properties and chemical stability of the porous carbon microspheres, thereby achieving dual protection of loaded active substances. The mineralized modified porous carbon microcapsules of the present invention can be widely used in the adhesive system and paint film system of artificial boards to achieve long-lasting and stable slow-release antibacterial and fragrance-releasing effects, with a validity period of up to several years.

[0014] In a specific embodiment of the present invention, the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing an organic precursor; the organic precursor includes a cellulose-rich plant source or an organic-rich animal source; the plant source includes any one of wood fiber, straw and plant residue; the animal source includes any one of chitin, animal bones and cuticle.

[0015] In one embodiment of the present invention, the porous carbon microspheres are prepared by the following method:

[0016] (11) crushing and grinding the plant source or animal source, and then acid washing and / or alkali washing to obtain pretreated product I;

[0017] (12) adding a binder to the pretreated material I, mixing them uniformly, and then spheroidizing them to obtain spherical particles with a diameter in the micrometer scale, thereby obtaining pretreated material II;

[0018] (13) The pretreated product II is then carbonized in nitrogen or argon at 500-1000 °C for 1-10 hours to obtain a spherical material with a diameter of 30-50 μm, a mesoporous pore size of 2-50 nm, and a specific surface area of 300-1500 m 2 / g porous carbon microspheres;

[0019] (14) The porous carbon microspheres are then activated and dried to obtain the final porous carbon microspheres.

[0020] In a specific embodiment of the present invention, the pickling agent is hydrochloric acid or sulfuric acid, the pickling agent concentration is 1M-5M, and the reaction time is 1-3 hours;

[0021] The alkaline washing agent is sodium hydroxide or potassium hydroxide; the reaction pH value is 11-12, the reaction temperature is 60-90° C., and the reaction time is 2-4 hours.

[0022] In a specific embodiment of the present invention, the addition amount of the binder is 5-30%; the binder includes any one or a mixture of several of polypropylene, polyethylene, polylactic acid, starch, gum arabic and gelatin.

[0023] In one embodiment of the present invention, the spheroidization treatment includes wet spheroidization, spray drying spheroidization, extrusion molding, spheronization, oscillation spheroidization or spray cooling spheroidization.

[0024] In a specific embodiment of the present invention, the activation treatment includes physical activation and / or chemical activation; physical activation includes high-temperature steam or nitrogen activation; the reagent used for the chemical activation includes sodium hydroxide, potassium hydroxide or hydrogen peroxide.

[0025] In a specific embodiment of the present invention, the small molecule essential oil is an oil compound extracted from a plant with a molecular weight of <300; the plant is any one of mint, tea tree, rosemary, thyme and eucalyptus.

[0026] In a specific embodiment of the present invention, the organic matrix is a polysaccharide or protein, including any one of gelatin, sodium alginate, hyaluronic acid and carboxycellulose.

[0027] In a specific embodiment of the present invention, the inorganic salt solution is a cationic solution, including any one of sodium chloride, copper sulfate, potassium nitrate, sodium carbonate or calcium chloride.

[0028] In order to achieve the second object of the invention, the present invention can be implemented by the following technical solution: providing a method for preparing a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule, comprising:

[0029] The formulated amount of small molecule essential oil is loaded on the porous carbon microspheres, and then the organic matrix and inorganic salt solution are coated on the porous carbon microspheres loaded with the small molecule essential oil in sequence to obtain long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules.

[0030] The beneficial effects of adopting the above technical scheme are as follows: the present invention adopts bio-based porous carbon microspheres to load natural small molecule essential oils, and realizes organic-inorganic mineralization coating on the surface of microspheres through organic matrix and inorganic salt solution to improve the hardness, heat resistance and other properties of microsphere particles, and realize stable sustained release of aromatic active substances, which can last for more than 2 years; In the present invention, essential oil molecules interact with the surface of porous carbon microspheres through van der Waals forces and hydrogen bonds, and essential oil molecules can be adsorbed on the surface or pores of carbon microspheres, ensuring the loading and stability of essential oils; the organic matrix layer is coated on the surface of porous carbon microspheres, enhancing the encapsulation and release control of essential oils and avoiding rapid volatilization of essential oils; the organic matrix layer provides an attachment surface for the inorganic mineral layer, and the inorganic mineral layer is stably coated on the matrix layer through chemical reaction or physical deposition, thereby improving the heat resistance stability and sustained release performance of the overall composite material; this capsule can be stably and persistently soluble in adhesives and surface coatings for artificial boards, realizing a long-lasting and stable antibacterial and fragrance-releasing effect without producing toxic side effects.

[0031] In one embodiment of the present invention, a method for preparing a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule is provided, comprising:

[0032] (1) Preparation of porous carbon microspheres;

[0033] (2) The porous carbon microspheres, small molecule essential oil, deionized water and ethanol are mixed and uniformly dispersed at 5000-8000 r / min for 2-10 min to prepare porous carbon microspheres loaded with small molecule essential oil; the mass ratio of the porous carbon microspheres, small molecule essential oil, deionized water and ethanol is 1:0.1-1:1-3:10-20.

[0034] (3) Adding 20-50% by mass of an organic matrix solution to the product obtained in step (2), and then adding 0.5-1.5% by mass of a coupling agent and 0.5-1.5% by mass of a dispersant, mixing, stirring until the organic matrix is completely dissolved, and then homogenizing and dispersing at 5000-8000 r / min for 5-15 minutes;

[0035] (4) Adding an inorganic salt solution with a mass fraction of 10-30% to the product obtained in step (3), stirring and dispersing at 800-1000 r / min for 2-4 hours, filtering and drying, and obtaining a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule with an organic-inorganic mineral layer as the surface shell.

[0036] The beneficial effects of the above technical solution are as follows: the present invention uses natural plant essential oils as fragrance-releasing and antibacterial active substances, self-assembles into porous microspheres through plant-derived or animal-derived fibers, and obtains porous carbon microsphere adsorption carriers through hydrothermal carbonization-activation; due to the high hardness, porosity, and high specific surface area characteristics of the porous carbon microspheres, they can load more essential oil active substances and provide mechanical strength during the hot pressing process; at the same time, the thermal conductivity of carbon is low, and under short-term high temperature conditions during the material production process, it will play a role in high-temperature protection of the biologically active components loaded inside it, and then it is coated with a polysaccharide or protein organic matrix, and finally on this base An inorganic salt solution is introduced into the body to form an organic-inorganic mineral layer on the surface of the microspheres; on the one hand, the mineral layer containing inorganic ions can play a synergistic antiviral effect, and at the same time, the mineral layer with hardness, heat resistance and acid and alkali resistance further improves the physical and mechanical properties and chemical stability of the porous carbon microspheres, thereby achieving dual protection of loaded active substances; due to the addition of coupling agents, dispersants, surfactants, etc. during the preparation process, it maintains good interfacial compatibility with water; the mineralized modified porous carbon microcapsules can be widely used in the adhesive system and paint film system of artificial boards to achieve long-lasting and stable slow-release antibacterial and fragrance-releasing effects, with a validity period of up to several years.

[0037] In a specific embodiment of the present invention, the coupling agent is a mixture of a silane coupling agent isocyanatepropyltriethoxysilane and a silane coupling agent vinyltrimethoxysilane, with a mass ratio of 2:1; and the dispersant is sodium polyacrylate.

[0038] In order to achieve the third object of the invention, the present invention provides the use of long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules in the preparation of adhesives or paint films for artificial boards.

[0039] The beneficial effects of adopting the above technical solution are as follows: the fragrance-releasing antibacterial microcapsules of the present invention can be widely used in the adhesive system and paint film system of artificial boards, achieving long-lasting and stable slow-release antibacterial and fragrance-releasing effects of artificial board products, with a validity period of up to several years; the active substances (such as natural fragrances and antibacterial agents) in the microcapsules are gradually released, utilizing the control performance of the shell to avoid their rapid release in the early stage, thereby ensuring that they can continue to exert their effects during long-term use.

[0040] In the adhesive system, the microcapsule carrier encapsulates the aroma and antibacterial ingredients, and slowly releases these ingredients in the glued board through the degradation or dissolution of the microcapsule shell, which not only achieves the antibacterial effect, but also continuously releases the aroma, improves the indoor air quality, and enhances the added value of the artificial board; when the artificial board is glued and cured, the aroma and antibacterial ingredients inside the microcapsule will gradually be released during the use of the board. This slow-release feature can ensure long-term and effective antibacterial and aroma-releasing effects, extend the service life of the product and reduce odor.

[0041] In the paint film system, microcapsules can provide long-lasting and stable antibacterial and aroma release effects through a similar sustained-release principle; adding microcapsules to the paint can enable the paint film to maintain the gradual release of antibacterial ingredients and aroma after curing, thereby providing antibacterial protection and a fresh aroma for the painted surface.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) By using porous carbon microspheres to load natural small molecule organic essential oils, the spherical structure is stable, efficient loading and high loading capacity are characterized. Compared with traditional microcapsule coating technology, it effectively overcomes the problems of microcapsule breakage caused by external stress and low raw material utilization during the preparation process.

[0044] (2) The porous carbon microspheres loaded with active substances are coated with organic-inorganic secondary mineralization to resist pressure layer by layer from the outside to the inside, reducing the structural damage to the extract components caused by the short high temperature and high pressure process, and slowly releasing the effective ingredients of the essential oil through the mesoporous and microporous pathways to achieve long-lasting antibacterial and fragrance-releasing effects.

[0045] (3) Due to the presence of the mineralized layer, the microspheres can be stably present in some acidic and alkaline environments, making them suitable for adhesive systems and surface paint film systems in the processing of artificial boards, enhancing the performance of adhesives and paint films, and giving them certain flame retardant, antibacterial and fragrance-releasing functions. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] A long-lasting, stable and sustained-release antibacterial microcapsule with fragrance release, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: 30% porous carbon microspheres, 30% small molecule essential oil, 20% organic matrix, and 20% inorganic salt solution;

[0049] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0050] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 1M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, which can be done by vacuum filtration or centrifugation to remove excess acid solution;

[0051] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions at 60-90°C for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0052] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder polypropylene, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0053] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, pore size of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0054] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0055] (2) Take 6 g of the pore size of 30 nm, good sphericity and total pore volume of 0.412 cm prepared in step (1). 3 / g, specific surface area of 323m 2 / g porous carbon microspheres, 6g agarwood essential oil was dissolved in a mixed solvent of 102g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0056] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 4 g of sodium alginate solution, 0.2 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane as a silane coupling agent, and 0.2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1;

[0057] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 4 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 1000 rpm for 4 h to obtain the dispersion.

[0058] Example 2

[0059] A long-lasting, stable and sustained-release antibacterial microcapsule with fragrance release, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 60%, small molecule essential oil 10%, organic matrix 20%, inorganic salt solution 10%;

[0060] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0061] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 5 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, which can be done by vacuum filtration or centrifugation to remove excess acid solution;

[0062] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0063] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder, polylactic acid, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0064] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2 nm-50 nm, and specific surface area of 300-1500 m 2 / g;

[0065] (14) The reaction product (3) is subjected to nitrogen activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of carbon, generating oxides and other chemical products, which remove carbon atoms in carbon and leave a large number of pores; chemical reagents usually react with carbon materials to generate volatile products, remove unnecessary impurities in carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0066] (2) Take 6 g of the pore size of 28 nm, good sphericity and total pore volume of 0.498 cm prepared in step (1). 3 / g, specific surface area of 417m 2 / g porous carbon microspheres, 1g agarwood essential oil was dissolved in a mixed solvent of 17g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0067] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 2 g of sodium alginate solution, 0.2 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane as a silane coupling agent, and 0.2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1;

[0068] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 1 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 1000 rpm for 4 h to obtain the dispersion.

[0069] Example 3

[0070] A long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 50%, small molecule essential oil 10%, organic matrix 20%, inorganic salt solution 20%;

[0071] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0072] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 3 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, which can be done by vacuum filtration or centrifugation to remove excess acid solution;

[0073] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0074] (12) The obtained pretreated material (1) is evenly mixed with 10% by mass of a binder polypropylene, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0075] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0076] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0077] (2) Take 5 g of the pore size of 21 nm, good sphericity and total pore volume of 0.502 cm prepared in step (1). 3 / g, specific surface area of 531m 2 / g porous carbon microspheres, 1g agarwood essential oil was dissolved in a mixed solvent of 17g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0078] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 2 g of sodium alginate solution, 4 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane, and 2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1.

[0079] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 2 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 900 rpm for 3 h to obtain the dispersion.

[0080] Example 4

[0081] A long-lasting, stable and sustained-release antibacterial microcapsule with fragrance release, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 40%, small molecule essential oil 10%, organic matrix 40%, and inorganic salt solution 10%;

[0082] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0083] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 1 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, and vacuum filtration or centrifugation can be used to remove excess acid solution;

[0084] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0085] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder polypropylene, and spherical particles having a diameter of micrometer scale are prepared by spray drying and spheroidization technology;

[0086] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0087] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0088] (2) Take 4 g of the pore size of 18 nm, good sphericity and total pore volume of 0.687 cm prepared in step (1). 3 / g, specific surface area of 582m 2 / g porous carbon microspheres, 1g agarwood essential oil was dissolved in a mixed solvent of 17g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0089] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 4 g of sodium alginate, 0.2 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane as a silane coupling agent, and 0.2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1.

[0090] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 1 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 900 rpm for 3 h to obtain the dispersion.

[0091] Example 5

[0092] A long-lasting, stable and sustained-release antibacterial microcapsule with fragrance, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 45%, small molecule essential oil 15%, organic matrix 20%, inorganic salt solution 20%;

[0093] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0094] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 1 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, and vacuum filtration or centrifugation can be used to remove excess acid solution;

[0095] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0096] (12) The obtained pretreated material (1) is evenly mixed with 10% by mass of a binder polypropylene, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0097] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0098] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0099] (2) Take 4.5 g of the pore size of 7 nm, good sphericity and total pore volume of 0.793 cm prepared in step (1). 3 / g, specific surface area of 665m 2 / g porous carbon microspheres, 1.5g agarwood essential oil was dissolved in a mixed solvent of 25.5g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0100] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 2 g of sodium alginate, 0.2 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane as a silane coupling agent, and 0.2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1;

[0101] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 2 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 800 rpm for 2 h to obtain the dispersion.

[0102] Example 6

[0103] A long-lasting, stable and sustained-release antibacterial microcapsule with fragrance release, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 35%, small molecule essential oil 20%, organic matrix 20%, inorganic salt solution 25%;

[0104] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0105] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 1 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, and vacuum filtration or centrifugation can be used to remove excess acid solution;

[0106] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0107] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder polypropylene, and spherical particles having a diameter of micrometer scale are prepared by spray drying and spheroidization technology;

[0108] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0109] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0110] (2) Take 3.5 g of the pore size of 5 nm, good sphericity and total pore volume of 0.774 cm prepared in step (1). 3 / g, specific surface area of 633m 2 / g porous carbon microspheres, 2g agarwood essential oil was dissolved in a mixed solvent of 34g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0111] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 2 g of sodium alginate solution, 4 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane, and 2 g of sodium polyacrylate were added thereto, and magnetic stirring was applied at 60°C until the sodium alginate was completely dissolved. The mixture was homogenized and dispersed at 8000 rpm for 15 min; the mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1.

[0112] (4) The dispersion obtained in step (3) was allowed to stand for defoaming, and then 2.5 g of calcium chloride solution was added thereto. The mixture was mechanically stirred at 800 rpm for 2 h to obtain the dispersion.

[0113] Comparative Example 1

[0114] A long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 50%, small molecule essential oil 10%, organic matrix 20%, inorganic salt solution 20%;

[0115] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0116] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 3 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, which can be done by vacuum filtration or centrifugation to remove excess acid solution;

[0117] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0118] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder polypropylene, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0119] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0120] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0121] (2) Take 5 g of the pore size of 21 nm, good sphericity and total pore volume of 0.502 cm prepared in step (1). 3 / g, specific surface area of 531m 2 / g porous carbon microspheres, 1g agarwood essential oil was dissolved in a mixed solvent of 17g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0122] The difference between Comparative Example 1 and Example 3 is that only the emulsified essential oil loading of step 1 is performed.

[0123] Comparative Example 2

[0124] A long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule, wherein the total mass of the microcapsule raw material is 100%, the mass percentages of the components in the raw material are as follows: porous carbon microspheres 50%, small molecule essential oil 10%, organic matrix 20%, inorganic salt solution 20%;

[0125] The preparation method of the above-mentioned long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises the following steps: (1) preparing porous carbon microspheres: the porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing organic precursors; the organic precursors include plant sources rich in cellulose or animal sources rich in organic matter; the plant sources include any one of wood fiber, straw and plant residues; the animal sources include any one of chitin, animal bones and cuticles; the specific preparation process includes:

[0126] (11) Select wood fiber as raw material and crush and grind it to obtain a uniform fiber powder, which is then chemically pretreated, usually including acid washing, alkaline washing or a combination thereof, to remove impurities, hemicellulose and other non-fiber components; acid washing: the fiber powder is mixed with a hydrochloric acid solution with a concentration of 3 M; acid washing is carried out at room temperature or under heating conditions at 50°C-80°C, and the reaction time is usually 1-3 hours; the fiber is thoroughly washed with deionized water until the washing solution is neutral; the acid washed fiber is dehydrated, which can be done by vacuum filtration or centrifugation to remove excess acid solution;

[0127] Alkali washing: Mix the fiber powder with sodium hydroxide solution, adjust the pH to about 12, and react under heating conditions of 60℃-90℃ for 2-4 hours. Wash repeatedly with deionized water until the pH of the washing solution is neutral, and then dehydrate;

[0128] (12) The obtained pretreated material (1) is evenly mixed with 5% by mass of a binder polypropylene, and spherical particles having a diameter of micrometers are prepared by spray drying and spheroidization technology;

[0129] (13) The obtained product (2) is carbonized in nitrogen or argon at 500-1000 °C for 1-10 h to obtain porous carbon microspheres with good spherical shape, sphere diameter of 30-50 μm, mesopore diameter of 2-50 nm, and specific surface area of 300-1500 m 2 / g;

[0130] (14) The reaction product (3) is subjected to a high-temperature steam activation treatment, which mainly utilizes the reaction of chemical reagents with carbon to destroy some carbon-carbon bonds of the carbon, generating oxides and other chemical products, which remove carbon atoms in the carbon and leave a large number of pores; the chemical reagents usually react with the carbon material to generate volatile products, remove unnecessary impurities in the carbon, and wash away residual salts or activators, and then dry to obtain the final porous carbon microspheres;

[0131] (2) Take 5 g of the pore size of 21 nm, good sphericity and total pore volume of 0.502 cm prepared in step (1). 3 / g, specific surface area of 531m 2 / g porous carbon microspheres, 1g agarwood essential oil was dissolved in a mixed solvent of 17g ethanol / deionized water, mixed with a glass rod, and then homogenized and dispersed in a homogenizer at a speed of 5000 rpm for 10min; the mass ratio of small molecule essential oil, ethanol, and deionized water was 1:15:2.

[0132] (3) After the dispersion prepared in step (2) was allowed to stand for defoaming, 2 g of sodium alginate solution, 0.2 g of a mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane as a silane coupling agent, and 0.2 g of sodium polyacrylate were added thereto. The mixture was stirred magnetically at 60°C until the sodium alginate was completely dissolved, and homogenized and dispersed at 8000 rpm for 15 min. The mass ratio of the mixture of isocyanatepropyltriethoxysilane and vinyltrimethoxysilane was 2:1.

[0133] The difference between Comparative Example 2 and Example 3 is that only the organic layer coating of step 2 is performed.

[0134] The properties of the products obtained in Examples 1-6 of the present invention and the products of Comparative Examples 1-2 are shown in Table 1:

[0135] Table 1 Technical parameters of porous carbon microspheres

[0136]

[0137] As can be seen from Table 1, the prepared examples and comparative examples all have a good spherical morphology, the particle size is maintained at 10-40 μm, and the aroma substance content is maintained at 5-30%; the thermal decomposition temperature of the microspheres treated with the organic matrix and inorganic mineralization is significantly improved and maintained at 300-500°C, while the thermal decomposition temperature of the microspheres with only organic matrix coating and without coating is significantly reduced.

[0138] In order to further illustrate that the porous carbon microspheres of the present invention have high temperature resistance, high pressure resistance, fragrance release and antibacterial effects, the samples of Examples 1-6 and Comparative Examples 1-2 were respectively added to the glue for impregnated film paper, and the addition amount was 0.5% of the adhesive. The impregnated film paper was impregnated for 30 seconds, dried in an oven at 105°C for 10 minutes, and then attached to the ecological board. After hot pressing at 180°C for 10 minutes, it was placed for 30 days and subjected to antibacterial testing. The results are shown in Table 3; referring to the forestry industry standard LY / T 3236-2020 "Odor classification and evaluation method of artificial boards and their products", samples treated with accelerated sustained release at 60°C for different times were enriched in a dryer for 24 hours, and the odor was sensory graded by the olfactory personnel by manual sniffing, and the fragrance release score was recorded at a fixed location and time. The number of repeated specimens for each condition was 3, and 3-4 people participated in the sniffing. The results were averaged. This method can be used to guide the fragrance release evaluation in a closed space, as shown in Table 2;

[0139] Table 2 Test results of fragrance release performance of porous carbon microspheres used in ecological boards

[0140]

[0141] It can be seen from the data in Table 2 that the porous carbon microspheres prepared in Examples 1-6 still have obvious woody and floral scents after being used in ecological boards at 60°C for 480 hours of accelerated release, while in Comparative Example 1, the sample prepared by porous carbon microspheres loaded only with antibacterial essential oils has a significantly weakened woody and floral scent of only 0.3 levels; the sample prepared by porous carbon microspheres coated with an organic layer in Comparative Example 2 has a better sustained release effect than that in Comparative Example 1, but not as good as that in Examples 1-3.

[0142] Table 3 Antibacterial activity test results of porous carbon microspheres used in ecological boards

[0143]

[0144] It can be seen from the data in Table 3 that the porous carbon microspheres prepared in Examples 1-6 still have anti-Escherichia coli E. coli and Staphylococcus aureus S. aureus effects after being used in the eco-board; it can be seen from Comparative Examples 1-2 that the antibacterial effect of the eco-board prepared by the porous carbon microspheres loaded only with antibacterial essential oils is significantly weakened; and the antibacterial performance of the porous carbon microspheres coated with the organic layer is improved, but is still lower than that of the porous carbon microspheres after organic-inorganic mineralization.

[0145] In summary, the present invention provides a method for preparing porous carbon microcapsules with good pressure resistance, heat resistance, corrosion resistance and long-lasting stable sustained release of high-load natural active fragrance-releasing antibacterial substances. Bio-based porous carbon microcapsules are loaded with natural small molecule essential oils, and organic-inorganic mineralization coating is achieved on the surface through an organic matrix and an inorganic salt solution to improve the hardness, heat resistance, corrosion resistance and other properties of the microsphere particles and the long-lasting stable sustained release of fragrance-releasing antibacterial active substances. The method can be suitable for the production process of artificial board adhesives.

Claims

1. A long-lasting, stable and sustained-release antibacterial microcapsule, characterized by: Calculated by mass percentage, it includes the following components: Porous carbon microspheres 30-60%, small molecule essential oil 10-30%, organic matrix 20-50% and inorganic salt solution 10-30%; The porous carbon microspheres are bio-based porous carbon microspheres, which are prepared by carbonizing an organic precursor; the organic precursor includes a plant source rich in cellulose or an animal source rich in organic matter; the plant source includes any one of wood fiber, straw and plant residue; the animal source includes any one of chitin, animal bones and cuticle; The porous carbon microspheres are prepared by the following method: (11) crushing and grinding the plant source or animal source, and then acid washing and / or alkali washing to obtain pretreated product I; (12) adding a binder to the pretreated material I, mixing them uniformly, and then spheroidizing them to obtain spherical particles with a diameter in the micrometer scale, thereby obtaining pretreated material II; (13) The pretreated product II is then carbonized in nitrogen or argon at 500-1000 °C for 1-10 hours to obtain a spherical material with a diameter of 30-50 μm, a mesoporous pore size of 2-50 nm, and a specific surface area of 300-1500 m 2 / g porous carbon microspheres; (14) activating the porous carbon microspheres and drying them to obtain the final porous carbon microspheres; The pickling agent is hydrochloric acid or sulfuric acid, the pickling agent concentration is 1-5M, and the reaction time is 1-3 hours; The alkaline washing agent is sodium hydroxide or potassium hydroxide; the reaction pH is 11-12, the reaction temperature is 60-90°C, and the reaction time is 2-4 hours; The addition amount of the binder is 5-30%; the binder includes any one or a mixture of polypropylene, polyethylene, polylactic acid, starch, gum arabic and gelatin; The spheroidization treatment includes wet spheroidization, spray drying spheroidization, extrusion molding, spheronization, oscillation spheroidization or spray cooling spheroidization; The activation treatment includes physical activation and / or chemical activation; physical activation includes high-temperature steam or nitrogen activation; the reagent used for chemical activation includes sodium hydroxide, potassium hydroxide or hydrogen peroxide; The organic matrix is a polysaccharide or protein, including any one of gelatin, sodium alginate, hyaluronic acid and carboxycellulose; The inorganic salt solution is a cationic solution, including any one of sodium chloride, copper sulfate, potassium nitrate or sodium carbonate; The preparation method of the said long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsules comprises: The formulated amount of small molecule essential oil is loaded onto porous carbon microspheres, and then the organic matrix and inorganic salt solution are coated on the porous carbon microspheres loaded with small molecule essential oil in sequence to obtain a long-lasting, stable and sustained-release fragrance-releasing antibacterial microcapsule; specifically: (1) Preparation of porous carbon microspheres; (2) mixing the porous carbon microspheres, small molecule essential oil, deionized water and ethanol, and uniformly dispersing them at 5000-8000 r / min for 2-10 min to prepare porous carbon microspheres loaded with small molecule essential oil; the mass ratio of the porous carbon microspheres, small molecule essential oil, deionized water and ethanol is 1:0.1-1:1-3:10-20; (3) Adding 20-50% by mass of an organic matrix solution to the product obtained in step (2), and then adding 0.5-1.5% by mass of a coupling agent and 0.5-1.5% by mass of a dispersant, mixing, stirring until the organic matrix is completely dissolved, and then homogenizing and dispersing at 5000-8000 r / min for 5-15 minutes; (4) Adding an inorganic salt solution with a mass fraction of 10-30% to the product obtained in step (3), stirring and dispersing the mixture at 800-1000 r / min for 2-4 h, filtering and drying the mixture, and obtaining a long-lasting, stable, sustained-release, fragrance-releasing antibacterial microcapsule having an organic-inorganic mineral layer as its surface shell.

2. The long-lasting, stable and sustained-release antibacterial microcapsule according to claim 1, characterized in that: The small molecule essential oil is an oil compound extracted from a plant, and its molecular weight is less than 300; the plant is any one of mint, tea tree, rosemary, thyme and eucalyptus.

3. The long-lasting, stable and sustained-release antibacterial microcapsule according to claim 1, characterized in that: The coupling agent is a mixture of silane coupling agent isocyanate propyl triethoxysilane and silane coupling agent vinyl trimethoxysilane, with a mass ratio of 2:1; the dispersant is sodium polyacrylate.

4. Use of the long-lasting, stable, sustained-release aroma-releasing antibacterial microcapsules according to any one of claims 1 to 3 in the preparation of adhesives or paint films for artificial boards.

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