JP7443830B2 - Composite particles for deodorization, their manufacturing method, and deodorant - Google Patents

Description

The present invention relates to deodorizing composite particles, a method for producing the same, and a deodorant using the deodorizing composite particles.

In recent years, active efforts have been made to micronize cellulose fibers found in wood, which is a material with a low environmental impact, until at least one side of its structure is on the order of nanometers, and to use it as a new functional material.

For example, as shown in Patent Document 1, it is disclosed that micronized cellulose fibers, that is, cellulose nanofibers (hereinafter also referred to as CNFs), can be obtained by repeatedly subjecting wood cellulose to mechanical treatment using a blender or a grinder. There is. It has been reported that CNF obtained by this method has a minor axis diameter ranging from 10 to 50 nm and a major axis diameter ranging from 1 μm to 10 mm. This CNF is one-fifth lighter than steel, more than five times stronger, and has a huge specific surface area of more than 250 m ² /g, so it is expected to be used as a filler for reinforcing resins and as an adsorbent. ing.

In addition, active attempts are being made to produce CNF by chemically treating the cellulose fibers in wood so that they can be easily made fine, and then using a low-energy mechanical treatment using a household mixer to make the fibers fine. The method of the above chemical treatment is not particularly limited, but a method of introducing anionic functional groups into cellulose fibers to facilitate micronization is preferred. By introducing anionic functional groups into the cellulose fibers, the solvent can easily penetrate between the cellulose microfibril structures due to the osmotic pressure effect, and the energy required to refine the cellulose raw material can be significantly reduced.

The method for introducing the anionic functional group is not particularly limited, but for example, Non-Patent Document 1 discloses a method of selectively phosphoricating the surface of cellulose fine fibers using phosphoric esterifying treatment. ing. Further, Patent Document 2 discloses a method of carboxymethylating cellulose by reacting it with monochloroacetic acid or sodium monochloroacetate in a highly concentrated alkaline aqueous solution. Alternatively, carboxylic groups may be introduced by directly reacting cellulose with a carboxylic acid anhydride compound such as maleic acid or phthalic acid gasified in an autoclave.

In addition, a method of selectively oxidizing the surface of cellulose fine fibers using 2,2,6,6-tetramethylpiperidinyl-1-oxy radical (TEMPO), which is a relatively stable N-oxyl compound, as a catalyst. has also been reported (for example, see Patent Document 3). The oxidation reaction using TEMPO as a catalyst (TEMPO oxidation reaction) is an environmentally friendly chemical modification that proceeds in water at room temperature and pressure, and when applied to cellulose in wood, the reaction occurs inside the crystal. It is possible to selectively convert only the alcoholic primary carbons of the cellulose molecular chains on the crystal surface into carboxy groups without proceeding.

Cellulose single nanofibers (hereinafter also referred to as CSNF), which are dispersed into individual cellulose microfibril units in a solvent, are produced by the osmotic pressure effect accompanying the ionization of carboxy groups selectively introduced to the crystal surface by TEMPO oxidation. ) can be obtained. CSNF exhibits high dispersion stability derived from the carboxy groups on the surface. Wood-derived CSNF obtained from wood by the TEMPO oxidation reaction is a structure with a high aspect ratio of around 3 nm in short axis diameter and several tens of nm to several μm in long axis diameter, and its aqueous dispersion and molded body is reported to have high transparency. Further, Patent Document 4 reports that a laminated film obtained by coating and drying a CSNF dispersion has gas barrier properties.

A problem facing the practical application of CNF is that the solid content concentration of the resulting CNF dispersion is as low as about 0.1 to 5% by mass. For example, when attempting to transport a CNF dispersion, there is a problem in that it is equivalent to transporting a large amount of solvent, leading to a rise in transport costs and significantly impairing business viability. Further, when used as an additive for reinforcing resins, there are problems such as deterioration of addition efficiency due to low solid content and difficulty in compounding if water as a solvent is not compatible with the resin. Furthermore, when handled in a hydrated state, there is a risk that the hydrated CNF dispersion will rot, so measures such as refrigerated storage and preservative treatment are required, which may increase costs.

However, if the solvent of the CNF dispersion is simply removed by heat drying or the like, the CNF will aggregate, become keratinized, or form a film, making it difficult to stably function as an additive. Furthermore, since the solid content concentration of the CNF dispersion is low, the solvent removal step itself by drying requires a large amount of energy, which is another factor that impairs business viability.

As described above, handling CNF in the form of a dispersion liquid itself is a cause of impairing business viability, and therefore, it is strongly desired to provide a new handling mode that allows CNF to be handled easily.

As exemplified above, various studies have been made regarding the development of high-performance members that impart new functionality to micronized cellulose, including CNF or CSNF, which are carbon neutral materials.

On the other hand, the way pets are kept has changed in recent years.In the past, it was common to keep pets outdoors, such as in gardens, but due to the increase in condominiums and denser housing, more and more households are keeping pets indoors. ing. For this reason, pets often defecate indoors, and the use of pet toilets has become commonplace. When defecating indoors, the scattering of excrement and its odor become a problem, and many products are used to deal with this problem. These include pet litter and deodorizing spray.

There are two types of toilet litter: those that use water-absorbing polymers and bentonite powder to absorb and harden excrement, and those that use highly absorbent lump fibers or porous particles to adsorb excrement. However, all of them have little effect on odor prevention, and deodorants are often used in combination to compensate for this effect.

As a deodorant, a liquid agent containing a surfactant or porous inorganic particles as a deodorizing ingredient can be sprayed directly onto the source of the odor, or wiped off after spraying to suppress and remove the odor. (For example, Patent Document 5).

However, because they contain surfactants, they not only cause paint to peel off or stain on some flooring materials, but also surfactants are considered a problem as a contributing factor to environmental pollution. In addition, there is a concern that fine scratches may occur due to inorganic fine particles, and due to the high specific gravity of inorganic fine particles, precipitation and aggregation are likely to occur when dispersed in a liquid.

Thus, there is a strong desire for deodorizing materials that have low environmental impact and are excellent in deodorizing and dispersibility properties.

Japanese Patent Application Publication No. 2010-216021 International Publication No. 2014/088072 Japanese Patent Application Publication No. 2008-001728 International Publication No. 2013/042654 Japanese Patent Application Publication No. 2004-242516

Noguchi Y, Homma I, Matsubara Y. Complete nanofabrillation of cellulose prepared by phosphorylation. ellulose. 2017;24:1295.10.1007/s10570-017-1191-3

The present invention was made in view of the above circumstances, and provides a new deodorizing product that uses materials with low environmental impact without using surfactants, can remove and suppress bad odors, and is easy to handle. The object of the present invention is to provide composite particles, a method for producing the deodorizing composite particles, and a deodorant using the deodorizing composite particles.

The present invention has been made to solve the above problems, and a deodorizing composite particle according to one aspect of the present invention includes a core particle containing at least a biodegradable polymer , and at least a part of the surface of the core particle. The present invention is a composite particle having a covering layer, wherein the covering layer is made of finely divided cellulose, and the core particle is a deodorizing composite particle containing catechin .

In the deodorizing composite particles of the present invention, it is preferable that the core particles and the finely divided cellulose are bonded and inseparable.

A method for producing deodorizing composite particles according to one aspect of the present invention is a method for producing deodorizing composite particles characterized by sequentially comprising the following first to fourth steps.
1) First step: A step of defibrating the cellulose raw material in a solvent to obtain a dispersion of finely divided cellulose.
2) Second step: A step of obtaining a liquid mixture in which catechin is mixed with a liquid containing at least a biodegradable polymer.
3) Third step: emulsifying the droplets of the mixed liquid in the dispersion while covering at least a part of the surface of the droplets of the mixed liquid with the coating layer of the micronized cellulose. .
4) Fourth step: With at least a part of the surface of the droplet of the mixed liquid covered with the coating layer of the micronized cellulose, the droplet of the mixed liquid is solidified to form core particles. A step of making the core particles and the finely divided cellulose inseparable.

A deodorant according to one embodiment of the present invention is a deodorant characterized in that it contains the deodorizing composite particles of the present invention and is in the form of a powder with a solid content of 80% by mass or more.

Another deodorant of the present invention is a deodorant characterized in that the deodorant composite particles of the present invention are dispersed in a dispersion solvent and are in a liquid state.

Another deodorant of the present invention is a deodorant characterized in that the deodorizing composite particles of the present invention are blended into a base material and are shaped into granular chips.

According to the present invention, new deodorizing composite particles that can remove and suppress bad odors and are easy to handle using materials with low environmental impact, a method for producing the deodorizing composite particles, and the deodorizing composite particles are provided. A deodorant using composite particles can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of deodorizing composite particles according to a first embodiment of the present invention. It is a schematic diagram for explaining the manufacturing method of the composite particle for deodorization based on the second embodiment of this invention. 2 is a characteristic diagram showing the results of measuring the spectral transmission spectrum of the aqueous CNF dispersion obtained in Example 1. FIG. FIG. 2 is a characteristic diagram showing the results of measuring the steady-state viscoelasticity of the aqueous CNF dispersion obtained in Example 1 using a rheometer. 1 is a photographic image showing the results of observing the deodorizing composite particles obtained in Example 1 using a scanning electron microscope. 1 is a photographic image showing the results of observing the deodorizing composite particles obtained in Example 1 at high magnification using a scanning electron microscope.

Embodiments of the present invention will be described below with reference to the drawings. However, in each of the figures described below, mutually corresponding parts are given the same reference numerals, and descriptions of overlapping parts will be omitted as appropriate. Further, this embodiment is an example of a configuration for embodying the technical idea of the present invention, and the material, shape, structure, arrangement, dimensions, etc. of each part are not specified as described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

[Deodorizing composite particles]
FIG. 1 is a schematic diagram of deodorizing composite particles 4 according to the first embodiment of the present invention. The deodorizing composite particles 4 are composite particles having a core particle 3 made of at least one type of polymer and a coating layer 2 that covers at least a part of the surface of the core particle 3, and the coating layer 2 is made of fine particles. The core particles 3 are made of cellulose 1 and are characterized by having a functional component including a material having a deodorizing function. Further, it is preferable that the core particles 3 and CNF1 are bonded and inseparable.

The above-mentioned "micronized cellulose" means fibrous cellulose, and hereinafter, unless otherwise specified, it will be collectively referred to as CNF, including CSNF.

The above-mentioned "inseparable" means, for example, that the dispersion containing the deodorizing composite particles 4 is centrifuged to remove the supernatant, and then a solvent is added and redispersed to purify and wash the deodorizing composite particles 4. CNF1 and core particles 3 do not separate, and the state of coating of core particles 3 with CNF1 is maintained even after repeating the operation or the operation of repeatedly washing with a solvent by filtration washing using a membrane filter. means.

The coating state can be confirmed, for example, by observing the surface of the deodorizing composite particles 4 using a scanning electron microscope. Although the bonding mechanism between CNF1 and core particles 3 in the deodorizing composite particles 4 is not certain, since the deodorizing composite particles 4 are produced using an O/W type emulsion stabilized by CNF1 as a template, Since the droplets 5 are solidified with the CNF1 in contact with the droplets 5 inside the emulsion, at least a portion of the CNF1 present on the surface of the core particles 3 is contained in the deodorizing composite particles 4 obtained after solidification. It is expected that the particles will be incorporated into the core particles 3.

For the above reasons, it is presumed that CNF1 is physically immobilized on the core particles 3 after solidification, and eventually the core particles 3 and CNF1 reach an inseparable state.

As mentioned above, the O/W emulsion is also referred to as an oil-in-water emulsion, in which water is the continuous phase and oil is dispersed therein as oil droplets (oil particles). .

In addition, since the deodorizing composite particles 4 are produced using the O/W type emulsion stabilized by CNF1 as a template, the shape of the deodorizing composite particles 4 is a true spherical shape derived from the O/W type emulsion. is a feature. Specifically, the coating layer 2 made of CNF1 is formed with a relatively uniform thickness on the surface of the truly spherical core particle 3. The average thickness of the coating layer 2 can be determined by, for example, cutting the deodorizing composite particles 4 fixed with an embedding resin using a microtome and observing them with a scanning electron microscope, and then obtaining a cross-sectional image of the deodorizing composite particles 4 in the image. It can be calculated by measuring the thickness of the coating layer 2 at 100 random locations on the image and taking the average value.

Further, the deodorizing composite particles 4 are characterized in that they are uniformly coated with a coating layer 2 having a relatively uniform thickness, and specifically, the coefficient of variation of the thickness of the coating layer 2 mentioned above is 0. It is preferably 5 or less, more preferably 0.4 or less. If the coefficient of variation of the thickness of the coating layer 2 containing CNF1 exceeds 0.5, it may be difficult to recover the deodorizing composite particles 4, for example. Here, the coefficient of variation is the value obtained by dividing the standard deviation of the thickness of the coating layer 2 in the cross-sectional image of the deodorizing composite particles 4 observed at 100 random points on the screen by the average value. be.

The core particles 3 constituting the deodorizing composite particles 4 of the present invention have a functional component containing a material having a deodorizing function. Examples of materials having a deodorizing function include diphenols such as catechol, 4-methylcatechol, 5-methylcatechol, resorcinol, 2-methylresorcinol, 5-methylresorcinol, and hydroquinone; 4,4'-biphenyldiol; Biphenyldiols such as 3,4'-biphenyldiol; catechins such as catechin, epicatechin, epigallocatechin, and epicatechin gallate; catechol derivatives such as dopa, dopamine, chlorogenic acid, caffeic acid, paracoumaric acid, and tyrosine. Plant-derived polyphenols extracted from plants; examples include those derived from coffee, apples, grapes, teas (green tea, roasted tea, black tea, oolong tea, mate tea, etc.), persimmons, soybeans, cacao, rosemary, aloe, etc. .

Preferably, the functional component further includes at least one of a fragrance and a disinfectant. Since the core particles 3 have a functional component containing these materials, the composite particles of the present invention can have functions such as an aromatic effect and a bactericidal effect in addition to a deodorizing effect, and the effect of suppressing bad odors is further enhanced. . The functional component may be mixed directly with the polymerizable monomer or polymer, but if mixing is difficult, it may be mixed using a solvent that has an affinity for the polymerizable monomer or polymer and the functional component. Furthermore, the functional component does not need to be completely compatible with the polymerizable monomer or polymer, and may be in a state of being dispersed within the polymerizable monomer or polymer.

Flavors include natural fragrances extracted from animals and plants, synthetic fragrances chemically synthesized, and blended fragrances prepared by blending multiple types of fragrances. Examples of natural fragrances include floral fragrances such as jasmine, rose, carnation, lilac, cyclamen, lily of the valley, violet, lavender, and osmanthus; citrus fragrances such as orange, lemon, and lime; spices such as cinnamon and nutmeg; cypress essential oil; Examples include wood essential oils such as cypress essential oil and cedar essential oil. Examples of synthetic fragrances include hydrocarbons such as limonene, pinene, and camphene; alcohols such as linalool, geraniol, menthol, citronellol, and benzyl alcohol; aldehydes such as citral, citronellal, nonadienal, benzaldehyde, and cinnamic aldehyde; acetophenone; Ketones such as methylacetophenone, methylnonylketone, ilone, menthone, phenols such as methylanisole, eugenol, lactones such as decalactone, nonyllactone, undecalactone, linalyl acetate, geranyl acetate, benzyl acetate, terpinyl acetate, acetic acid Examples include esters such as citronellyl, methyl benzoate, ethyl benzoate, isoamyl benzoate, benzyl benzoate, methyl cinnamate, and ethyl cinnamate.

Bactericidal agents include ambam, sulfur, eclomesol, triphenyltin chloride, tripropyltin chloride, nickel chloride, benzalkonium chloride, basic copper chloride, basic copper sulfate, captan, guanidine, griseofulvin, chloramphenicol. , triphenyltin acetate, tributyltin acetate, nickel acetate, sodium hypochlorite, diclozoline, cycloheximide, ziclone, dithianon, zineb, dimethylambam, ziram, triphenyltin hydroxide, streptomycin, cerocidin, difortan, thiadiazine, thiabendazole , thiophanate, thiophanate methyl, triazine, nitrostyrene, novobiocin, validamycin, hydroxyisoxazole, fabam, folpet, propiquel, propineb, benomyl, polyoxin, polycarbamate, formaldehyde, mancozeb, maneb, methiram, MAF, PCP, etc. .

It is preferable that at least one type of polymer contained in the core particles 3 constituting the deodorizing composite particles 4 of the present invention is a biodegradable polymer. Biodegradability refers to the property of being consumed by microorganisms and decomposing into carbon dioxide gas, water, etc. The CNF1 used as the coating layer 2 of the present invention is also a biodegradable material, and the core particles 3 are also biodegradable, so the obtained deodorizing composite particles 4 are biodegradable composite particles and have an environmental impact. This makes it possible to reduce the Specifically, cellulose acetate derivatives such as cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate, polylactic acids such as polylactic acid, and copolymers of lactic acid and other hydroxycarboxylic acids; polybutylene succinate, polyethylene Dibasic acid polyesters such as succinate and polybutylene adipate, polycaprolactones such as polycaprolactone, copolymers of caprolactone and hydroxycarboxylic acid, polyhydroxybutyrate, and copolymers of polyhydroxybutyrate and hydroxycarboxylic acid. Polyhydroxybutyrates such as polymers, aliphatic polyesters such as polyhydroxybutyric acid, copolymers of polyhydroxybutyric acid and other hydroxycarboxylic acids, polyamino acids, polyester polycarbonates, natural resins such as rosin, etc. It will be done.

[Method for producing deodorizing composite particles]
FIG. 2 is a schematic diagram for explaining a method for manufacturing deodorizing composite particles 4 according to a second embodiment of the present invention. The method for producing deodorizing composite particles 4 according to the second embodiment of the present invention includes the first step)
A step of defibrating the cellulose raw material in a solvent to obtain a dispersion liquid 6 of CNF1. 2nd step) A step of obtaining a mixed liquid in which a functional component including at least one material having a deodorizing function is mixed with a liquid consisting of at least one type of polymerizable monomer or polymer. 3rd step) A step of emulsifying the droplets 5 of the mixed liquid in the dispersion 6 with at least a part of the surface of the droplets 5 of the mixed liquid covered with the coating layer 2 of CNF1 (see FIG. a)). 4th step) With at least a part of the surface of the droplet 5 of the mixed liquid covered with the coating layer 2 of CNF1, the droplet 5 of the mixed liquid is solidified to form the core particles 3. Step of making CNF1 inseparable (see FIG. 2(b)). It is characterized by sequentially including the above first to fourth steps.

The first to fourth steps will be explained in detail below.

<First step>
The first step is to obtain a CNF dispersion by defibrating the cellulose raw material in a solvent. First, various cellulose raw materials are dispersed in a solvent to form a suspension. The concentration of the cellulose raw material in the suspension is preferably 0.1% by mass or more and less than 10% by mass. If the concentration of the cellulose raw material in the suspension is less than 0.1% by mass, it is not preferable because there is a tendency for too much solvent to impair productivity. In addition, if the concentration of the cellulose raw material in the suspension is 10% by mass or more, the suspension tends to rapidly increase in viscosity as the cellulose raw material is defibrated, making uniform defibration processing difficult. do not have.

The solvent used for preparing the suspension preferably contains 50% by mass or more of water. When the proportion of water in the suspension is less than 50% by mass, dispersion of CNF1 tends to be inhibited in the step of defibrating the cellulose raw material in a solvent to obtain a CNF dispersion, which will be described later. Moreover, as the solvent contained other than water, a hydrophilic solvent is preferable. There are no particular limitations on the hydrophilic solvent, but alcohols such as methanol, ethanol, and isopropanol; and cyclic ethers such as tetrahydrofuran are preferred.

If necessary, for example, the pH of the suspension may be adjusted in order to improve the dispersibility of cellulose and CNF1 produced. Examples of alkaline aqueous solutions used for pH adjustment include sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia aqueous solution, tetramethylammonium hydroxide aqueous solution, tetraethylammonium hydroxide aqueous solution, tetrabutylammonium hydroxide aqueous solution, Examples include organic alkalis such as an aqueous solution of benzyltrimethylammonium hydroxide. An aqueous sodium hydroxide solution is preferred from the viewpoint of cost.

Subsequently, the suspension is subjected to a physical defibration treatment to refine the cellulose raw material. Physical defibration treatment methods are not particularly limited, but include, for example, high-pressure homogenizers, ultra-high-pressure homogenizers, ball mills, roll mills, cutter mills, planetary mills, jet mills, attritors, grinders, juicer mixers, homomixers, and ultrasonic homogenizers. , nanogenizers, and mechanical treatments such as underwater counter-impact. By performing such a physical defibration treatment, the cellulose in the suspension is refined, and a dispersion of cellulose (CNF) 1 is obtained, in which at least one side of the structure is refined to the order of nanometers. be able to. Further, the number average minor axis diameter and the number average major axis diameter of the obtained CNF1 can be adjusted by the time and number of times of the physical defibration treatment at this time.

In the above manner, a dispersion of cellulose 1 (CNF dispersion) is obtained, in which at least one side of the structure is micronized to the order of nanometers. The obtained dispersion can be used as it is or after dilution, concentration, etc., as a stabilizer for the O/W emulsion described below.

Generally, CNF1 has a fiber shape derived from a microfibril structure, and therefore, CNF1 used in the manufacturing method of this embodiment preferably has a fiber shape within the range shown below. That is, the shape of CNF1 is preferably fibrous. Further, the fibrous CNF1 may have a number average short axis diameter of 1 nm or more and 1000 nm or less, preferably 2 nm or more and 500 nm or less.

Here, if the number average minor axis diameter is less than 1 nm, a highly crystalline and rigid CNF fiber structure cannot be obtained, and it becomes difficult to stabilize the emulsion and carry out a polymerization reaction using the emulsion as a template. Tend. On the other hand, when the number average short axis diameter exceeds 1000 nm, the size becomes too large to stabilize the emulsion, and it tends to be difficult to control the size and shape of the composite particles 4 obtained. be.

Further, the number average major axis diameter is not particularly limited, but it is preferably 50 nm or more and 5 times or more the number average minor axis diameter. If the number average major axis diameter is less than 5 times the number average minor axis diameter, it is not preferable because it tends to become difficult to sufficiently control the size and shape of the composite particles.

Note that the number average short axis diameter of the CNF fibers is determined by measuring the short axis diameter (minimum diameter) of 100 fibers by, for example, transmission electron microscopy and atomic force microscopy, and finding the average value thereof. On the other hand, the number average major axis diameter of the CNF fibers is determined by measuring the major axis diameter (maximum diameter) of 100 fibers by, for example, transmission electron microscopy and atomic force microscopy, and finding the average value thereof.

Although the type and crystal structure of cellulose that can be used as a raw material for CNF1 are not particularly limited, it is preferable that the cellulose has a fiber shape derived from a microfibril structure. Moreover, it is preferable that the crystal structure of CNF1 is cellulose I type. Specifically, raw materials consisting of cellulose type I crystals include, in addition to wood-based natural cellulose, non-wood-based natural celluloses such as cotton linters, bamboo, hemp, bagasse, kenaf, bacterial cellulose, ascidian cellulose, and valonia cellulose. can be used. Furthermore, regenerated cellulose typified by rayon fibers and cupra fibers made of cellulose type II crystals can also be used.

From the viewpoint of ease of material procurement, it is preferable to use wood-based natural cellulose as the raw material. The wood-based natural cellulose is not particularly limited, and for example, those commonly used in the production of cellulose nanofibers, such as softwood pulp, hardwood pulp, and waste paper pulp, can be used. Softwood pulp is preferred because of its ease of purification and refinement.

Furthermore, the CNF raw material is preferably chemically modified. More specifically, it is preferable that an anionic functional group be introduced onto the crystal surface of the CNF raw material. This is because the introduction of anionic functional groups into the cellulose crystal surface makes it easier for the solvent to penetrate between the cellulose crystals due to the osmotic pressure effect, making it easier for the cellulose raw material to become finer.

The type and method of introduction of the anionic functional group to be introduced into the cellulose crystal surface are not particularly limited, but carboxy groups and phosphoric acid groups are preferred. Carboxy groups are more preferred because they can be easily introduced selectively onto the cellulose crystal surface.

The method for introducing carboxy groups onto the surface of cellulose fibers is not particularly limited. Specifically, for example, carboxymethylation may be performed by reacting cellulose with monochloroacetic acid or sodium monochloroacetate in a highly concentrated alkaline aqueous solution. Alternatively, carboxylic groups may be introduced by directly reacting cellulose with a carboxylic acid anhydride compound such as maleic acid or phthalic acid gasified in an autoclave. Furthermore, co-oxidants are used under relatively mild aqueous conditions in the presence of N-oxyl compounds such as TEMPO, which have high selectivity for the oxidation of alcoholic primary carbon while preserving the structure as much as possible. You may also use the same method. Oxidation using an N-oxyl compound is more preferable in terms of selectivity of the carboxyl group introduction site and reduction of environmental burden.

Here, as the N-oxyl compound, for example, TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxy radical), 2,2,6,6-tetramethyl-4-hydroxypiperidine- 1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-ethoxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetamido-2, 2,6,6-tetramethylpiperidine-N-oxyl, and the like. Among them, TEMPO, which has high reactivity, is preferred. The amount of the N-oxyl compound to be used may be a catalytic amount and is not particularly limited. Usually, it is about 0.01 to 5.0% by mass based on the solid content of the wood-based natural cellulose to be oxidized.

Examples of oxidation methods using N-oxyl compounds include a method in which wood-based natural cellulose is dispersed in water and oxidized in the presence of an N-oxyl compound. At this time, it is preferable to use a co-oxidizing agent together with the N-oxyl compound. In this case, in the reaction system, the N-oxyl compound is sequentially oxidized by a co-oxidizing agent to produce an oxoammonium salt, and the cellulose is oxidized by the oxoammonium salt. According to this oxidation treatment, the oxidation reaction proceeds smoothly even under mild conditions, and the efficiency of introducing carboxy groups is improved. When the oxidation treatment is performed under mild conditions, it is easier to maintain the crystal structure of cellulose.

Co-oxidants that can promote the oxidation reaction include, for example, halogens, hypohalous acid, halous acids, perhalogen acids, salts thereof, halogen oxides, nitrogen oxides, peroxides, etc. Any oxidizing agent, if any, can be used. Sodium hypochlorite is preferred because of its ease of availability and reactivity. The amount of the co-oxidant used is not particularly limited and may be an amount that can promote the oxidation reaction. Usually, it is about 1 to 200% by mass based on the solid content of the wood-based natural cellulose to be oxidized.

Furthermore, at least one compound selected from the group consisting of bromides and iodides may be used in combination with the N-oxyl compound and the co-oxidizing agent. This allows the oxidation reaction to proceed smoothly and improves the efficiency of introducing carboxy groups. As such a compound, sodium bromide or lithium bromide is preferable, and sodium bromide is more preferable in terms of cost and stability. The amount of the compound used may be any amount that can promote the oxidation reaction, and is not particularly limited. Usually, it is about 1 to 50% by mass based on the solid content of the wood-based natural cellulose to be oxidized.

The reaction temperature of the oxidation reaction is preferably 4°C or more and 80°C or less, more preferably 10°C or more and 70°C or less. If the reaction temperature of the oxidation reaction is less than 4° C., the reactivity of the reagent tends to decrease and the reaction time tends to become longer. When the reaction temperature of the oxidation reaction exceeds 80°C, side reactions are promoted, and the sample cellulose becomes lower molecular weight, resulting in the collapse of the highly crystalline and rigid CNF fiber structure, which is used as a stabilizer for O/W emulsions. This tends to be difficult.

Further, the reaction time of the oxidation treatment can be appropriately set in consideration of the reaction temperature, the desired amount of carboxy groups, etc., and is usually about 10 minutes to 5 hours, although it is not particularly limited.

The pH of the reaction system during the oxidation reaction is not particularly limited, but is preferably 9 to 11. When the pH is 9 or higher, the reaction can proceed efficiently. If the pH exceeds 11, side reactions may proceed and the decomposition of the cellulose sample may be accelerated. Further, in the oxidation treatment, as the oxidation progresses, the pH in the system decreases due to the production of carboxy groups, so it is preferable to maintain the pH of the reaction system at 9 to 11 during the oxidation treatment. A method for maintaining the pH of the reaction system at 9 to 11 includes, for example, a method of adding an alkaline aqueous solution in response to a decrease in pH.

Examples of the alkaline aqueous solution include sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonia aqueous solution, tetramethylammonium hydroxide aqueous solution, tetraethylammonium hydroxide aqueous solution, tetrabutylammonium hydroxide aqueous solution, and benzyltrimethylammonium hydroxide. Examples include organic alkalis such as aqueous solutions. An aqueous sodium hydroxide solution is preferred from the viewpoint of cost.

The oxidation reaction by the N-oxyl compound can be stopped, for example, by adding alcohol to the reaction system. At this time, it is preferable to maintain the pH of the reaction system within the above range. The alcohol to be added is preferably a low molecular weight alcohol such as methanol, ethanol, or propanol in order to quickly complete the reaction, and ethanol is particularly preferred in view of the safety of by-products produced by the reaction.

The reaction solution after the oxidation treatment may be directly subjected to the micronization process, but in order to remove catalysts such as N-oxyl compounds, impurities, etc., the oxidized cellulose contained in the reaction solution is recovered and washed with a cleaning solution. It is preferable. Oxidized cellulose can be recovered by a known method such as filtration using a glass filter or a nylon mesh with a pore size of 20 μm. Pure water is preferable as the cleaning liquid used for cleaning oxidized cellulose.

When the obtained TEMPO oxidized cellulose is defibrated, cellulose single nanofibers (CSNF) having a uniform fiber width of around 3 nm are obtained. When CSNF is used as a raw material for CNF1 of composite particles 5, the particle size of the resulting O/W emulsion tends to be uniform due to its uniform structure.

As described above, the CNF used in this embodiment can be obtained through the steps of oxidizing a cellulose raw material and micronizing it to form a dispersion. Further, the content of carboxyl groups introduced into CNF is preferably 0.1 mmol/g or more and 5.0 mmol/g or less, more preferably 0.5 mmol/g or more and 2.0 mmol/g or less.

Here, if the amount of carboxy groups is less than 0.1 mmol/g, there is a tendency that it becomes difficult to micronize and uniformly disperse cellulose because the solvent entry effect due to osmotic pressure effect does not work between cellulose microfibrils. be. Furthermore, if the amount of carboxy groups exceeds 5.0 mmol/g, cellulose microfibrils become low-molecular due to side reactions associated with chemical treatment, making it impossible to form a highly crystalline and rigid CNF fiber structure. It tends to be difficult to use as a stabilizer for type emulsions.

<Second process>
The second step is a step of obtaining a liquid mixture in which a liquid consisting of at least one type of polymerizable monomer or polymer is mixed with a functional component including at least one type of material having a deodorizing function. Specifically, this is a step of obtaining a liquid mixture that will become the emulsion droplets 5 (see FIG. 2(a)) that will be formed in the third step described below. There is a way.

The mixing ratio of the polymerizable monomer or polymer and the functional component is within the range of 50/50 to 95/5, preferably 70/30 to 90/10 in weight ratio of polymerizable monomer or polymer/functional component. is within the range of If the amount of the polymerizable monomer or polymer is lower than 50, it will be difficult to form composite particles, and if it is higher than 95, the effect of the functional component will be weakened.

(First example of second step)
The first example of the second step is a method in which the functional component is added to a liquid made of a polymerizable monomer containing a polymerization initiator to obtain a mixed liquid.

Polymerizable monomers that can be used to obtain a mixture of polymerizable monomers containing a functional component and an initiator include polymer monomers that have a polymerizable functional group in their structure. , which is liquid at room temperature, is not completely miscible with water, can form a polymer (high molecular polymer) through a polymerization reaction, and can be made into an emulsion when mixed with the CNF dispersion in the third step, i.e. It is not particularly limited as long as it is completely incompatible with water.

The polymerizable monomer has at least one polymerizable functional group. A polymerizable monomer having one polymerizable functional group is also referred to as a monofunctional monomer. Furthermore, a polymerizable monomer having two or more polymerizable functional groups is also referred to as a polyfunctional monomer. The type of polymerizable monomer is not particularly limited, but examples include (meth)acrylic monomers and vinyl monomers. Furthermore, it is also possible to use a polymerizable monomer (for example, ε-caprolactone, etc.) having a cyclic ether structure such as an epoxy group or an oxetane structure.

Note that the expression "(meth)acrylate" includes both "acrylate" and "methacrylate."

Examples of monofunctional (meth)acrylic monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl. (meth)acrylate, t-butyl (meth)acrylate, glycidyl (meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl ( meth)acrylate, isodecyl(meth)acrylate, lauryl(meth)acrylate, tridecyl(meth)acrylate, cetyl(meth)acrylate, stearyl(meth)acrylate, benzyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate, 3 -Methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phosphoric acid (meth)acrylate, ethylene oxide modified phosphoric acid (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide modified phenoxy (meth)acrylate, propylene oxide Modified phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide modified nonylphenol (meth)acrylate, propylene oxide modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyl Oxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen phthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl ( meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, adamantyl acrylate with monovalent mono(meth)acrylate derived from 2-adamantane and adamantane diol Examples include adamantane derivative mono(meth)acrylates such as.

Examples of difunctional (meth)acrylic monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, and nonanediol di(meth)acrylate. ) acrylate, ethoxylated hexanediol di(meth)acrylate, propoxylated hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate Di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl hydroxypivalate di(meth)acrylate, etc. Examples include meth)acrylate.

Examples of trifunctional or higher-functional (meth)acrylic monomers include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, and tris-2-hydroxy. Tri(meth)acrylates such as ethyl isocyanurate tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, etc. Trifunctional (meth)acrylate compounds, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta( Trifunctional or higher functional (meth)acrylate compounds such as meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane hexa(meth)acrylate, and some of these (meth)acrylates with alkyl groups or ε- Examples include polyfunctional (meth)acrylate compounds substituted with caprolactone.

As monofunctional vinyl monomers, liquids that are incompatible with water at room temperature are preferred, such as vinyl ethers, vinyl esters, aromatic vinyls, and especially styrene and styrene monomers.

Examples of (meth)acrylates among monofunctional vinyl monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, Lauryl (meth)acrylate, alkyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofur Furyl (meth)acrylate, allyl (meth)acrylate, diethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, heptafluorodecyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, ) acrylate, tricyclodecanyl (meth)acrylate, etc.

Examples of monofunctional aromatic vinyl monomers include styrene, such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylstyrene, isopropenyltoluene, isobutyltoluene, and tert-butylstyrene. , vinylnaphthalene, vinylbiphenyl, 1,1-diphenylethylene and the like.

Examples of the polyfunctional vinyl monomer include polyfunctional groups having an unsaturated bond such as divinylbenzene. A liquid that is incompatible with water at room temperature is preferred.

For example, specific examples of polyfunctional vinyl monomers include (1) divinyls such as divinylbenzene, 1,2,4-trivinylbenzene, and 1,3,5-trivinylbenzene, (2) ethylene glycol Dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexamethylene glycol dimethacrylate, neopentyl glycol dimethacrylate Dimethacrylates such as methacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2-bis(4-methacryloxydiethoxyphenyl)propane, (3) trimethylolpropane trimethacrylate, triethylolethane trimethacrylate, etc. Trimethacrylates, (4) Ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, 1,3-dipropylene glycol diacrylate, 1,4-dibutylene glycol diacrylate, 1,6 -Hexylene glycol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2-bis(4-acryloxypropoxyphenyl)propane, 2,2-bis(4-acryloxydiacrylate) diacrylates such as (ethoxyphenyl)propane, (5) triacrylates such as trimethylolpropane triacrylate and triethylolethane triacrylate, (6) tetraacrylates such as tetramethylolmethanetetraacrylate, (7) others, Examples include tetramethylene bis(ethyl fumarate), hexamethylene bis(acrylamide), triallyl cyanurate, and triallyl isocyanurate.

For example, specific examples of functional styrenic monomers include divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, divinylxylene, divinylbiphenyl, bis(vinylphenyl)methane, bis(vinylphenyl)ethane, bis(vinylphenyl)ethane, phenyl)propane, bis(vinylphenyl)butane, and the like.

In addition to these, polyether resins, polyester resins, polyurethane resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, etc. having at least one polymerizable functional group can be used. Yes, the material is not particularly limited.

The above polymerizable monomers may be used alone or in combination of two or more types.

Further, the polymerizable monomer may contain a polymerization initiator in advance. Examples of common polymerization initiators include radical initiators such as organic peroxides and azo polymerization initiators.

Examples of organic peroxides include peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxycarbonates, and peroxyesters.

Examples of the azo polymerization initiator include ADVN and AIBN.

For example, 2,2-azobis(isobutyronitrile) (AIBN), 2,2-azobis(2-methylbutyronitrile) (AMBN), 2,2-azobis(2,4-dimethylvaleronitrile) (ADVN) , 1,1-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2-azobisisobutyrate (MAIB), 4,4-azobis(4-cyanovaleric acid) (ACVA), 1, 1-azobis(1-acetoxy-1-phenylethane), 2,2-azobis(2-methylbutyramide), 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2- Azobis(2-methylamidinopropane) dihydrochloride, 2,2-azobis[2-(2-imidazolin-2-yl)propane], 2,2-azobis[2-methyl-N-(2-hydroxyethyl) propionamide], 2,2-azobis(2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2-azobis(N-butyl-2-methylpropionamide), 2,2 -azobis(N-cyclohexyl-2-methylpropionamide) and the like.

If a polymerizable monomer containing a polymerization initiator is used in the second step, the polymerization initiator will be included in the polymerizable monomer droplets 5 inside the emulsion particles when an O/W emulsion is formed. , the polymerization reaction progresses more easily when polymerizing the monomer inside the emulsion in the fourth step described below.

The weight ratio of the polymerizable monomer and polymerization initiator that can be used in the second step is not particularly limited, but it is usually 0.1 part by mass or more of the polymerization initiator per 100 parts by mass of the polymerizable monomer. preferable. If the amount of the polymerizable monomer is less than 0.1 part by mass, the polymerization reaction will not proceed sufficiently and the yield of composite particles 4 will tend to decrease, which is not preferable.

(Second example of second step)
A second example of the second step is a method in which a polymer that is solid at room temperature is dissolved in a solvent with low compatibility with the dispersion liquid, and the functional component is added to obtain a mixed liquid.

Polymers that can be used to obtain a mixed solution in which a functional component is added to a polymer that is solid at room temperature dissolved in a solvent with low compatibility with the CNF dispersion include the above-mentioned polymerizable monomers. Examples include polymers obtained by polymerizing. Further, as a solvent for dissolving a polymer that is solid at room temperature, a solvent having low compatibility with the CNF dispersion is preferable. When the solubility in water is high, emulsification tends to be difficult because the solvent easily dissolves from the polymer phase into the water phase. If there is no solubility in water, the solvent cannot migrate from the polymer phase, so it tends to be extremely difficult to obtain composite particles.

Further, the boiling point of the solvent for dissolving the polymer is preferably 90°C or lower. When the boiling point is higher than 90° C., the CNF dispersion liquid tends to evaporate before the solvent that dissolves the polymer, making it extremely difficult to obtain composite particles. Specific examples of the solvent for dissolving the polymer include dichloromethane, chloroform, 1,2-dichloroethane, and benzene.

(Third example of second step)
The third example of the second step is a method in which a polymer that is solid at room temperature is heated to a temperature above which it has fluidity to melt it, and the functional component is added to obtain a liquid mixture.

Examples of polymers that are solid at room temperature and can be used to melt a polymer that is solid at room temperature by heating it to a temperature at which it has fluidity or higher to obtain a liquid mixture with a functional component are: It has fluidity, and the temperature at which it has fluidity is the melting point or glass transition temperature. The melting point or glass transition temperature of the added polymer is preferably 40°C or higher and 90°C or lower.

When the melting point or glass transition temperature of the polymer is less than 40°C, it tends to be difficult to solidify at room temperature, making it extremely difficult to obtain a composite. Additionally, if the melting point or glass transition temperature of the polymer is 90°C or higher, water, which is the solvent for the CNF dispersion that is heated together, tends to vaporize rather than dissolve the polymer, making it difficult to form an emulsion. There is.

Therefore, specific examples of polymers that can be used in this embodiment include poly-S-methylheptene, polydecene, polyvinyl palmitate, polyvinyl stearate, cis-1,4-polychloroprene, and cis-1,4-polychloroprene. -1,3 pentadiene, it
trans-1,4-poly-1,3 hexadiene, it trans-1,4-poly-
1,3 heptadiene, it trans-1,4-poly-1,3 octadiene, polyhexamethylene oxide, polyoctamethylene oxide, polybutadiene oxide, polytetramethylene sulfide, polypentamethylene sulfide, polyhexamethylene sulfide, polymethylene thiol Examples include tetramethylene sulfide, polyethylenethiotetramethylene sulfide, polytrimethylene disulfide, and the like.

<3rd process>
In the third step, the droplets are emulsified in the CNF dispersion obtained in the first step, with at least a portion of the surface of the droplets of the mixed liquid obtained in the second step covered with a CNF coating layer. (See FIG. 2(a)).

More specifically, the mixed liquid obtained in the second step with no affinity is added to the CNF dispersion obtained in the first step, the mixed liquid is dispersed as droplets 5 in the CNF dispersion, and the liquid This is a step of coating at least a portion of the surface of the droplet 5 with CNF1 to produce an O/W type emulsion stabilized by CNF1.

The weight ratio of the CNF dispersion liquid and the mixed liquid that can be used in the third step is not particularly limited, but it is preferable that the mixed liquid is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of CNF fibers. If the mixed liquid is less than 1 part by mass, the yield of deodorizing composite particles 4 tends to decrease, which is not preferable. Moreover, if the mixed liquid exceeds 50 parts by mass, it tends to become difficult to uniformly coat the droplets 5 with CNF1, which is not preferable.

The method for producing the O/W emulsion is not particularly limited, but general emulsification treatments, such as various homogenizer treatments and mechanical stirring treatments, can be used. Specifically, high-pressure homogenizers, ultra-high-pressure homogenizers, all-purpose homogenizers, Mechanical treatments include ball mills, roll mills, cutter mills, planetary mills, jet mills, attritors, grinders, juicer mixers, homomixers, ultrasonic homogenizers, nanogenizers, underwater counter-impingement, paint shakers, and the like. Further, a combination of a plurality of mechanical treatments may be used.

For example, when using an ultrasonic homogenizer, a mixed liquid is added to the CNF dispersion obtained in the first step to obtain a mixed solvent, and the tip of the ultrasonic homogenizer is inserted into the mixed solvent to perform ultrasonic treatment. The processing conditions of the ultrasonic homogenizer are not particularly limited, but for example, the frequency is generally 20 kHz or higher, and the output is generally 10 W/cm ² or higher. Although the processing time is not particularly limited, it is usually about 10 seconds to 1 hour.

By the above ultrasonic treatment, the droplets 5 are dispersed in the CNF dispersion liquid, and emulsification progresses, and CNF1 is selectively adsorbed to the liquid/liquid interface between the droplets 5 and the CNF dispersion liquid. 5 is coated with CNF1 to form a stable structure as an O/W type emulsion. An emulsion that is stabilized by adsorption of solid matter at the liquid/liquid interface is academically referred to as a "Pickering emulsion." As mentioned above, the mechanism by which Pickering emulsions are formed by CNF fibers is not clear, but since cellulose has hydrophilic sites derived from hydroxyl groups and hydrophobic sites derived from hydrocarbon groups in its molecular structure, it is considered an amphiphilic emulsion. Since it exhibits medium properties, it is thought to be adsorbed at the liquid/liquid interface between the hydrophobic monomer and the hydrophilic solvent due to its amphipathic properties.

The O/W emulsion structure can be confirmed, for example, by optical microscopic observation. The particle size of the O/W emulsion is not particularly limited, but is usually about 0.1 μm to 1000 μm.

In the O/W emulsion structure, the CNF layer (coating layer 2) formed on the surface layer of the droplet 5
Although the thickness is not particularly limited, it is usually about 3 nm to 1000 nm. The thickness of the CNF layer (covering layer 2) can be measured using, for example, cryo-TEM.

<4th step>
The fourth step is to solidify the droplets 5 to form core particles 3 while covering at least a part of the surface of the droplets 5 of the mixed liquid with the coating layer 2 of CNF1. This is a step of covering at least a portion with CNF1 to make the core particles 3 and CNF1 inseparable (see FIG. 2(b)).

In the second step, when the method of the first example is used to obtain a mixed liquid by adding the functional component to a liquid consisting of a polymerizable monomer containing a polymerization initiator, the method of polymerizing the polymerizable monomer is particularly limited. It is not limited and can be appropriately selected depending on the type of polymerizable monomer and the type of polymerization initiator used. Examples of methods for polymerizing the above-mentioned polymerizable monomers include suspension polymerization.

The specific suspension polymerization method is not particularly limited either, and any known method can be used. For example, this is carried out by heating the O/W type emulsion prepared in the third step, in which the droplets 5 containing the functional component, the polymerization initiator, and the polymerizable monomer are coated with CNF 1 and stabilized, while stirring. be able to. The stirring method is not particularly limited, and any known method can be used, and specifically, a disperser or a stirrer can be used.

Alternatively, only heat treatment may be performed without stirring. Further, the temperature conditions during heating can be appropriately set depending on the type of polymerizable monomer and the type of polymerization initiator, but preferably 20 degrees or more and 90 degrees or less. If the heating temperature is less than 20 degrees Celsius, the reaction rate of polymerization tends to decrease, which is not preferable, and if it exceeds 90 degrees CNF dispersion liquid tends to evaporate, which is not preferable.

The time for the polymerization reaction can be appropriately set depending on the type of polymerizable monomer and the type of polymerization initiator, but is usually about 1 hour to 24 hours. Further, the polymerization reaction may be carried out by ultraviolet irradiation treatment, which is a type of electromagnetic wave. In addition to electromagnetic waves, particle beams such as electron beams may also be used.

In the second step, the polymer that is solid at room temperature was dissolved in a solvent with low compatibility with the dispersion liquid, and the functional component was added to obtain a mixed liquid using the method of the second example. In this case, the polymer can be solidified by heating the emulsion and volatilizing the solvent in which the polymer was dissolved. Temperature conditions during heating can be appropriately set depending on the type of solvent to be dissolved, but are preferably higher than the boiling point of the solvent and lower than 90 degrees. If the heating temperature is lower than the boiling point of the solvent, the movement of the solvent to the aqueous phase will be slow, and if it exceeds 90 degrees, the CNF dispersion liquid will tend to evaporate, which is not preferable.

In the second step, when the method of the third example is used, in which a polymer that is solid at room temperature is heated to a temperature above which it has fluidity and melted, and the functional component is added to obtain a mixed liquid, The polymer can be solidified by cooling the emulsion to a temperature below which the polymer has fluidity.

Through the steps described above, core particles 3 whose surfaces are at least partially covered with CNF and which are inseparable from CNF 1 are obtained as a dispersion in a dispersion solvent. Further, by removing the dispersion solvent, deodorizing composite particles 4 as a dry solid are obtained (see FIG. 2(c)).

That is, the state immediately after the solidification reaction is completed is a state in which a large amount of water and free CNF1 that do not contribute to the formation of the coating layer of the deodorizing composite particles 4 are mixed in the dispersion of the deodorizing composite particles 4. It becomes. Therefore, it is necessary to collect and refine the produced deodorizing composite particles 4.

As the recovery/purification method, washing by centrifugation or washing by filtration is preferable. A known method can be used as a cleaning method using centrifugation. Specifically, the deodorizing composite particles 4 are sedimented by centrifugation, the supernatant is removed, and the operation of redispersing in a water/methanol mixed solvent is repeated. Finally, the deodorizing composite particles 4 can be recovered by removing residual solvent from the sediment obtained by centrifugation.

Known methods can be used for filtration and cleaning, for example, repeating suction filtration with water and methanol using a PTFE membrane filter with a pore size of 0.1 μm, and finally removing residual solvent from the paste remaining on the membrane filter. The deodorizing composite particles 4 can then be recovered.

After removing excess solvent by centrifugation or filtration, it can be obtained as a dry solid by further heat drying in an oven. At this time, the obtained dry solid does not become film-like or aggregate-like, but is obtained as a fine-textured powder. Although the reason for this is not certain, it is known that normally, when the solvent is removed from the CNF dispersion, CNF1 particles strongly aggregate and form a film.

On the other hand, in the case of the dispersion liquid for obtaining the above deodorizing composite particles 4, since the CNF1 is a truly spherical composite particle fixed on the surface of the core particle 3, the CNF1 does not aggregate with each other even if the solvent is removed. Since there is no contact between the composite particles and only points between the composite particles, the dry solid is thought to be obtained as a fine-textured powder. In addition, since there is no aggregation of the deodorizing composite particles 4, it is easy to redisperse the deodorizing composite particles 4 obtained as a dry powder in a solvent, and even after redispersion, the surface of the core particles 3 Figure 2 shows dispersion stability derived from CNF1 bound to .

The dry powder of the deodorizing composite particles 4 is a dry solid that contains almost no solvent and can be redispersed in the solvent. Specifically, the solid content percentage can be 80% by mass or more, further 90% by mass or more, and furthermore 95% by mass or more. Since most of the solvent can be removed, favorable effects can be obtained from the viewpoints of, for example, reduction in transportation costs, prevention of spoilage, improvement in addition rate, and improvement in kneading efficiency with resin.

Note that when the solid content rate is increased to 80% by mass or more by drying treatment, since CNF1 easily absorbs moisture, there is a possibility that the solid content rate will decrease over time due to adsorption of moisture in the air. However, considering the technical concept of the present invention, which is characterized in that the deodorizing composite particles 4 can be easily obtained as a dry powder and can be redispersed, it is considered that It can be said that deodorizing composite particles manufactured by a dry solid manufacturing method including a step of increasing the solid content to 80% by mass or more fall within the technical scope of the present invention.

As described above, in the method for producing deodorizing composite particles of the present invention, an O/W Pickering emulsion using CNF1 is formed, and the droplets 5 inside the emulsion are solidified to form solid core particles 3. By doing so, it is possible to obtain deodorizing composite particles 4 in which the core particles 3 and CNF 1 are bonded and inseparable. By using CNF1, it is possible to form droplets 5 without using additives such as surfactants, and it is possible to obtain deodorizing composite particles 4 with high dispersibility.
[Deodorants]
By directly sprinkling the obtained deodorizing dry powder on pet excrement or its surroundings, the foreign odor or excrement itself will be adsorbed to the CNF that makes up the coating layer, and the odor will be deodorized by the functional ingredients contained within. Fragrances can be used to alleviate unpleasant odors, and disinfectants can be used to kill bacteria that cause unpleasant odors. In addition, since it is a powder, by sprinkling it on the excrement, if the excrement is solid, it will coat the surface of the excrement, and if the excrement is liquid, it will be absorbed by the coating layer of the deodorizing composite particles and excreted. It becomes easier to process things.

Furthermore, the obtained deodorizing composite particles can be used as a deodorizing liquid by dispersing them in a solvent. The solvent that can be used as a dispersion medium for dispersing the deodorizing composite particles is preferably water or an aqueous solvent prepared by adding a water-soluble alcohol or the like to water. Considering the volatility when the obtained deodorizing liquid is sprayed onto pet excrement, etc. and wiped off, a mixed solution of water and water-soluble alcohol is preferable. , those containing 30 to 80 parts by mass of a water-soluble alcohol component are preferred.

The mixing ratio of the dispersion medium and the deodorizing composite particles in the deodorizing liquid is preferably 0.1 to 30 parts by mass of the deodorizing composite particles to 100 parts by mass of the dispersion medium.

Further, the obtained deodorizing composite particles can be blended into a base material and formed into particles to be used as a deodorizing chip. Specifically, the deodorizing chip can be used as litter for pets. Pet litter is placed in a place where pets defecate, and the litter absorbs the excrement that comes into contact with the litter and disposes of the excrement. It makes it easier.

Base materials used to form deodorizing chips include pulp fibers, wood flour, kenaf flour, vegetable base materials such as okara, and mineral base materials such as bentonite, clay, attapulgite, sepiolite, and galeonite. can be mentioned. These base materials only absorb excrement, but by incorporating deodorizing composite particles into the base material, a deodorizing effect can be imparted. In addition, since deodorizing composite particles are composed of organic materials, if the base material is a flammable material, it can be disposed of by incineration, and if the base material is a biodegradable material, the core particles can be biodegraded. By making it into a polymer with properties, it will not decompose and pollute the soil even if it is buried in the soil.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and may include design changes within the scope of the gist of the present invention. In addition, the components shown in the above-described first embodiment of the deodorizing composite particles, the method of manufacturing the deodorizing composite particles of the second embodiment, and the application to a deodorant may be appropriately combined. Is possible.

Hereinafter, the present invention will be explained in detail based on Examples, but the technical scope of the present invention is not limited to these Examples. In each of the following examples, "%" indicates mass % (w/w%) unless otherwise specified.

<Example 1>
[First step: Step of obtaining CNF dispersion]
(TEMPO oxidation of wood cellulose)
70 g of softwood kraft pulp was suspended in 3500 g of distilled water, a solution of 0.7 g of TEMPO and 7 g of sodium bromide dissolved in 350 g of distilled water was added, and the mixture was cooled to 20°C. 450 g of an aqueous sodium hypochlorite solution having a concentration of 2 mol/L and a density of 1.15 g/mL was added dropwise thereto to start an oxidation reaction. The temperature in the system was always kept at 20° C., and the pH during the reaction was kept at 10 by adding a 0.5N aqueous sodium hydroxide solution. When the total amount of sodium hydroxide added to the weight of cellulose reached 3.50 mmol/g, about 100 mL of ethanol was added to stop the reaction. Thereafter, filtration and washing with distilled water was repeated using a glass filter to obtain oxidized pulp.

(Measurement of carboxy group amount of oxidized pulp)
0.1 g of solid content of the oxidized pulp and reoxidized pulp obtained by the TEMPO oxidation was weighed, dispersed in water at a concentration of 1%, and hydrochloric acid was added to adjust the pH to 2.5. Thereafter, the amount of carboxy groups (mmol/g) was determined by conductivity titration using a 0.5M aqueous sodium hydroxide solution. The result was 1.6 mmol/g.

(Defibration treatment of oxidized pulp)
1 g of the oxidized pulp obtained by the above TEMPO oxidation was dispersed in 99 g of distilled water and micronized using a juicer mixer for 30 minutes to obtain a CNF aqueous dispersion with a CNF concentration of 1%. The CNF dispersion was placed in a quartz cell with an optical path length of 1 cm, and the spectral transmission spectrum was measured using a spectrophotometer (manufactured by Shimadzu Corporation, "UV-3600"). The results are shown in FIG. As is clear from FIG. 3, the CNF aqueous dispersion exhibited high transparency.

Further, the number average minor axis diameter of CNF contained in the CNF aqueous dispersion was 3 nm, and the number average major axis diameter was 1110 nm. Furthermore, the results of steady viscoelasticity measurement using a rheometer are shown in FIG. As is clear from FIG. 4, the CNF dispersion exhibited thixotropic properties.

<Second step: Step of obtaining a mixed liquid containing functional components>
For 10 g of divinylbenzene (hereinafter also referred to as DVB), which is a polymerizable monomer, 1 g of 2,2-azobis-2,4-dimethylvaleronitrile (hereinafter also referred to as ADVN), which is a polymerization initiator, and as a function-generating component. 1 g of catechin (derived from green tea), which has a deodorizing effect, was dissolved.

<Third step: Step of producing O/W type emulsion>
Next, when the entire amount of the DVB/ADVN/catechin mixture was added to 40 g of a CNF dispersion with a CNF concentration of 1%, the DVB/ADVN/catechin mixture and the CNF dispersion each formed into two layers with high transparency. separated.

Next, the shaft of an ultrasonic homogenizer was inserted from the liquid level of the upper layer of the mixed liquid separated into two layers, and ultrasonic homogenizer treatment was performed for 3 minutes at a frequency of 24 kHz and an output of 400 W. The appearance of the mixed solution after treatment with an ultrasonic homogenizer was that of a cloudy emulsion. When a drop of the mixed solution was placed on a slide glass, sealed with a cover glass, and observed under an optical microscope, countless emulsion droplets of about 1 to several μm were formed, indicating that the dispersion was stabilized as an O/W emulsion. was confirmed.

<Fourth step: Step of obtaining deodorizing composite particles coated with CNF by polymerization reaction>
The O/W type emulsion dispersion was placed in a water bath at 70°C and treated for 8 hours while stirring with a stirrer to carry out a polymerization reaction. After 8 hours of treatment, the dispersion was cooled to room temperature. There was no change in the appearance of the dispersion before and after the polymerization reaction. When the obtained dispersion liquid was treated with a centrifugal force of 75,000 g (g is gravitational acceleration) for 5 minutes, a precipitate was obtained. The supernatant was removed by decantation to collect the sediment, which was then washed repeatedly with pure water and methanol using a PTFE membrane filter with a pore size of 0.1 μm.

The purified and collected product thus obtained was redispersed at a concentration of 1%, and the particle size was evaluated using a particle size distribution meter (NANOTRAC UPA-EX150, Nikkiso Co., Ltd.), and the average particle size was 2.1 μm. Next, the purified and collected product was air-dried and further vacuum-dried for 24 hours at a room temperature of 25 degrees Celsius to obtain a fine-textured dry powder (deodorizing composite particles).

(Shape observation using a scanning electron microscope)
The results of observing the obtained dry powder using a scanning electron microscope are shown in FIGS. 5 and 6. As is clear from Figure 5, by carrying out the polymerization reaction using the O/W type emulsion droplets as a template, countless true spherical deodorizing composite particles derived from the shape of the emulsion droplets were formed. This was confirmed. Further, as shown in FIG. 6, it was confirmed that the surface was uniformly covered with CNF having a width of several nm.

In addition, despite repeated washing by filtration, the surface of the deodorizing composite particles was equally and uniformly coated with CNF1. Core particle 3 and CNF1, which is CNF, were considered to be bonded, and it was shown that core particle 3 and CNF1 were inseparable.

(Evaluation of redispersibility)
When dry powder of deodorizing composite particles was added to pure water at a concentration of 1% and redispersed using a stirrer, it was easily redispersed and no aggregation was observed. Furthermore, when the particle size was evaluated using a particle size distribution meter, the average particle size was 2.1 μm, the same as before drying, and there was no signal indicating aggregation in the data from the particle size distribution meter.

The above results indicate that deodorizing composite particles can be obtained as powder without forming a film upon drying, and have good redispersibility, even though their surfaces are coated with CNF. It was done.

<Example 2>
In the second step of Example 1, conditions were the same as in Example 1, except that 7 g of DVB and 3 g of cellulose acetate butyrate (hereinafter also referred to as CAB), which is a biodegradable compound, were used instead of 10 g of DVB. The deodorizing composite particles according to Example 2 were prepared, and various evaluations were conducted in the same manner.

<Example 3>
Except that in the first step of Example 1, instead of TEMPO oxidation, a phosphoric acid esterified CNF dispersion obtained by performing a phosphoric acid esterification treatment according to Non-Patent Document 1 cited as a prior art document was used. The deodorizing composite particles according to Example 2 were produced under the same conditions as in Example 1, and various evaluations were performed in the same manner.

<Example 4>
In the third step of Example 1, 6 g of polystyrene (hereinafter referred to as PS) as a polymer forming the core particles 3 was dissolved in 4 g of dichloromethane (boiling point: 39.6° C.). The entire amount of the polystyrene/dichloromethane mixed solution was added to 40 g of the CNF dispersion used in Example 1.

Next, the above mixture was subjected to ultrasonic homogenizer treatment for 3 minutes at a frequency of 24 kHz and an output of 400 W in the same manner as in Example 1 to obtain an O/W emulsion dispersion.

Next, the O/W type emulsion dispersion was placed in a water bath at 70°C and treated for 8 hours while stirring with a stirrer to volatilize dichloromethane. After 8 hours of treatment, the dispersion was treated in the same manner as in Example 1 to obtain a dry powder (deodorizing composite particles).

<Example 5>
In the third step of Example 4, the same procedure as in Example 4 was used except that polycaprolactone (hereinafter also referred to as PCL), which is a biodegradable compound, was used instead of PS, and chloroform was used instead of dichloromethane. The deodorizing composite particles according to Example 5 were prepared under the same conditions, and various evaluations were conducted in the same manner.

<Example 6>
In the third step of Example 1, 10 g of polyhexamethylene oxide (hereinafter also referred to as PHMO, melting point: 58 ° C.) as a polymer forming the core particles 3 was added to 40 g of the CNF dispersion used in Example 1. did.

Next, the above mixed solution was heated to 80° C. using a water bath to melt the PHMO, and then subjected to ultrasonic homogenizer treatment for 3 minutes at a frequency of 24 kHz and an output of 400 W as in Example 1. , an O/W type emulsion dispersion was obtained.

Next, the O/W emulsion dispersion was cooled to room temperature. Finally, the above dispersion was treated in the same manner as in Example 1 to obtain a dry powder (deodorizing composite particles).

<Example 7>
In the third step of Example 6, conditions were the same as in Example 6, except that paraffin wax (hereinafter referred to as paraffin, melting point: 69°C), which is a biodegradable compound, was used instead of PHMO. The deodorizing composite particles according to Example 7 were produced and various evaluations were conducted in the same manner.

<Comparative example 1>
In the first step of Example 1, production of deodorizing composite particles according to Comparative Example 1 was attempted under the same conditions as in Example 1, except that pure water was used instead of the CNF dispersion.

<Comparative example 2>
The deodorizing composite particles according to Comparative Example 2 were prepared under the same conditions as in Example 1, except that in the first step of Example 1, a carboxymethyl cellulose (hereinafter also referred to as CMC) aqueous solution was used instead of TEMPO oxidation. I tried to make it.

<Comparative example 3>
The deodorizing product according to Comparative Example 3 was prepared under the same conditions as in Example 2, except that in the first step of Example 2, an 8% aqueous solution of polyvinyl alcohol (hereinafter also referred to as PVA) was used instead of the CNF dispersion. We attempted to create composite particles.

<Comparative example 4>
Comparative Example 4 was carried out under the same conditions as Example 1, except that a dispersion of commercially available polylactic acid fine particles (trade name: Toray Pearl PLA, Toray Industries, Ltd.) at a concentration of 1% was used instead of the composite particles of the present invention. We attempted to create composite particles for deodorization.

<Comparative example 5>
In the third step of Example 5, production of deodorizing composite particles according to Comparative Example 5 was attempted under the same conditions as Example 5, except that xylene (boiling point: 144 ° C.) was used instead of chloroform. .

<Comparative example 6>
Comparative Example 6 was carried out under the same conditions as Example 6 except that polybutyl acrylate (glass transition temperature: -54°C, melting point: 48°C) was used instead of PHMO in the third step of Example 6. An attempt was made to produce such deodorizing composite particles.

<Comparative example 7>
In the third step of Example 7, conditions were the same as in Example 7, except that amide wax (trade name: ITOHWAX-J630, melting point: 135°C, Yamakei Sangyo, hereinafter referred to as ITOWAX) was used instead of paraffin. An attempt was made to produce deodorizing composite particles according to Comparative Example 7.

<Comparative example 8>
A comparison was made under the same conditions as in Example 1, except that in the first step of Example 1, a 5% aqueous solution of sodium lauryl sulfate (hereinafter also referred to as SLS), which is a surfactant, was used instead of the CNF dispersion. An attempt was made to produce deodorizing composite particles according to Example 8.

[Evaluation criteria]
The suitability of the third step was determined as follows.
○: Formation of an O/W type emulsion is possible. ×: Formation of an O/W type emulsion is not possible. Whether or not the fourth step can be performed was determined as follows.
○: True spherical particles were obtained as the emulsion mold in the fourth step. ×: The above particles were not obtained. Furthermore, the redispersibility was evaluated as follows.
○: The obtained deodorizing composite particles were dispersed in the solvent (water) without agglomeration. ×: They were agglomerated without being dispersed. Regarding the evaluation of deodorizing properties, 1 g of deodorizing composite particles was placed in a 500 ml Erlenmeyer flask. and 0.1 g of ammonia were added to the flask, the flask was covered with a lid, and the flask was allowed to stand for 2 hours in an airtight state.The odor inside the flask was then sniffed to evaluate its deodorizing properties.
○: Ammonia odor cannot be felt from inside the flask. ×: Ammonia odor can be felt from inside the flask. The necessity of using a surfactant was determined as follows.
○: No surfactant was used in the manufacturing process of the deodorizing composite particles. ×: A surfactant was used in the manufacturing process of the deodorizing composite particles.

[Evaluation results]
The evaluation results of the above Examples 1 to 7 and Comparative Examples 1 to 8 are summarized in Table 1. In Table 1, the emulsion stabilizer refers to the additive used to stabilize the O/W emulsion in the third step, and for example, CNF in the first embodiment of the present invention Equivalent to. Furthermore, the diagonal lines in each cell in the comparative example in Table 1 indicate that the process became impossible to perform during each process, and the subsequent process was not performed.

As is clear from the evaluation results in Table 1, in Examples 1 to 7, deodorizing properties and dispersibility were achieved regardless of the type of CNF (TEMPO-oxidized CNF, phosphate-esterified CNF) or the type of core particles. It was confirmed that it is possible to produce deodorizing composite particles that do not require a surfactant during production, and that the present invention is successful in solving the problems of the present invention.

On the other hand, in Comparative Example 1, it was impossible to perform the third step. Specifically, even if the ultrasonic homogenizer treatment was carried out, the monomer layer and the CNF dispersion liquid layer remained separated into two layers, making it impossible to produce an O/W emulsion itself.

Furthermore, in Comparative Example 2, it was possible to form an O/W type emulsion in the third step. This is thought to be because CMC, like CNF, exhibited amphipathic properties and therefore functioned as an emulsion stabilizer. However, when the polymerization reaction was carried out in the subsequent fourth step, the emulsion collapsed, making it impossible to obtain composite particles using the O/W emulsion as a template. The reason for this is not certain, but since CMC is water-soluble, it is likely to be weak as a coating layer to maintain the emulsion shape during the polymerization reaction, and therefore the emulsion may collapse during the polymerization reaction. Conceivable.

Furthermore, in Comparative Example 3, polymerization was possible in the fourth step and recovery as a powder was achieved, but the resulting powder had poor redispersibility and deodorizing properties.

In addition, in Comparative Example 4, commercially available PLA fine particles with a similar structure and not coated with CNF were used, but when observing the shape with a scanning electron microscope, it was not possible to observe that the surface of the fine particles was coated with CNF. Ta.

Furthermore, in Comparative Example 5, it was possible to form an O/W type emulsion in the third step. However, in removing xylene in the fourth step, since water is used in the CNF dispersion, the temperature cannot be raised above the boiling point of xylene, so the droplets cannot be solidified, and the deodorizing composite No particles could be obtained.

Furthermore, in Comparative Example 6, it was possible to form an O/W type emulsion in the third step. However, even after cooling to room temperature in the fourth step, the polybutyl acrylate did not coagulate, the droplets could not be solidified, and deodorizing composite particles could not be obtained.

In addition, in Comparative Example 7, the temperature could not be raised higher than the boiling point of the water used for the CNF dispersion in the third step, and ITOWAX could not be melted, so it was difficult to form an O/W emulsion. I couldn't do that.

In addition, in Comparative Example 8, it was possible to polymerize in the fourth step and recover it as a powder, but a surfactant was used during the preparation, and the waste liquid released during the preparation was noticeably foamy. .

As explained above, the deodorizing composite particles of the present invention can be produced using materials with low environmental impact without using a surfactant during production, and are capable of removing and suppressing bad odors. Composite odor particles.

Moreover, the dry solid containing the deodorizing composite particles of the present invention is obtained as a fine-textured powder, and there is no aggregation of particles. Therefore, it is easy to redisperse the deodorizing composite particles obtained as a dry powder in a solvent again, and even after redispersion, the deodorizing composite particles obtained as a dry powder can be easily redispersed, and even after redispersion, the deodorizing composite particles derived from the CNF coating layer bonded to the surface of the deodorizing composite particles can be easily redispersed. Indicates dispersion stability.

Therefore, the deodorizing composite particles can be used as a deodorant in various forms such as dry powder, dispersion, and chip, and are easy to handle, have high dispersibility, and have a high deodorizing effect.

Moreover, according to the method for manufacturing deodorizing composite particles according to the present embodiment, it is possible to provide a method for manufacturing deodorizing composite particles that can be provided by a simple method.

Although the deodorizing composite particles of the present invention are intended to remove and suppress foreign odors caused by pet excrement, they can also be used for other types of foreign odors. Examples include garbage odor, cigarette odor, fabric odor such as bedding and curtains, household odor in the room, odor from shoe boxes and lockers, odor from sewage and drains, odor from oil such as kerosene, etc.

1... Micronized cellulose (cellulose nanofiber)
2...Coating layer 3...Core particles 4...Deodorizing composite particles 5...Droplets 6...Dispersion liquid

Claims (6)

A composite particle comprising a core particle containing at least a biodegradable polymer and a coating layer covering at least a part of the surface of the core particle,
The covering layer is made of finely divided cellulose,
the core particle contains catechin;
Composite particles for deodorization . The deodorizing composite particle according to claim 1, wherein the core particle and the finely divided cellulose are bonded and inseparable. A method for producing deodorizing composite particles, characterized by sequentially comprising the following first to fourth steps.
1) First step: A step of defibrating the cellulose raw material in a solvent to obtain a dispersion of finely divided cellulose.
2) Second step: A step of obtaining a liquid mixture in which catechin is mixed with a liquid containing at least a biodegradable polymer .
3) Third step: emulsifying the droplets of the mixed liquid in the dispersion while covering at least a part of the surface of the droplets of the mixed liquid with the coating layer of the micronized cellulose. .
4) Fourth step: With at least a part of the surface of the droplet of the mixed liquid covered with the coating layer of the micronized cellulose, the droplet of the mixed liquid is solidified to form core particles. A step of making the core particles and the finely divided cellulose inseparable. A deodorizer comprising the deodorizing composite particles according to claim 1 or 2 , which is in the form of a powder with a solid content of 80% by mass or more. A deodorant characterized in that the deodorizing composite particles according to claim 1 or 2 are dispersed in a dispersion solvent and are in a liquid state. A deodorant characterized in that the deodorizing composite particles according to claim 1 or 2 are blended into a base material and are shaped into granular chips.