Cellulose particles

Abstract

To provide a cellulosic particle that is superior in biodegradability and flexibility.SOLUTION: A cellulosic particle contains a first component that is cellulose, and a second component that is at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having a long-chain aliphatic group and at least one of a phenolic hydroxyl group or a monoglycidyl ether group directly bound to an aromatic group, and a (meth)acrylic compound (C).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to cellulose particles.

Background Art

[0002] Patent Document 1 proposes "an oil-based solid cosmetic containing surface-treated spherical cellulose powder having an average particle diameter of 1.0 to 30.0 μm." Patent Document 2 proposes "resin beads formed of a resin containing cellulose as a main component, having a cumulative 50% particle diameter based on volume of 50 μm or less, a sphericity of 0.7 to 1.0, a surface smoothness of 70 to 100%, a solidity of 50 to 100%, a biodegradation rate measured in accordance with JIS K6950:2000 (ISO 14851:1999) for 5 days of 20% or more, and a cellulose content in the resin of 90 to 100% by mass."

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide cellulose particles that are excellent in biodegradability and flexibility as compared with the case of not containing at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group together with a long-chain aliphatic group, and a (meth)acrylic acid-based compound (C) in cellulose particles containing cellulose.

Means for Solving the Problems

[0005] The above problems will be solved by the following means: <1> The first component is cellulose, Cellulose particles comprising a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C), at least one of these, and a second component selected from this group. <2> The content of the first component is 70% by mass or more and 95% by mass or less of the total content of the first and second components. <1> Cellulose particles as described above. <3> The total content of the second component is 5% by mass or more and 30% by mass or less, relative to the total content of the first and second components. <1> or <2> Cellulose particles as described above. <4> The fatty acid derivative (A) is a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms. <1> ~ <3> Cellulose particles as described in any one of the following. <5> The octanol / water partition coefficient of the fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms is 5 to 10. <4> Cellulose particles as described above. <6> The fatty acid derivative (A) is a fatty acid ethanolamide. <1> ~ <5> Cellulose particles as described in any one of the following. <7> The aromatic compound (B) is an aromatic compound (B0) having an aliphatic group having 8 to 20 carbon atoms, a phenolic hydroxyl group, and at least one of a monoglycidyl ether group directly bonded to the aromatic group. <1> ~ <3> Cellulose particles as described in any one of the following. <8> The octanol / water partition coefficient of the aromatic compound (B0) is between 5 and 20. <7> Cellulose particles as described above. <9> A mother particle containing the first component and the second component, A coating layer that covers the aforementioned mother particles, comprising at least one selected from the group consisting of polyamine compounds, waxes, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds, has <1> ~ <8> Cellulose particles as described in any one of the following. <10> The polyamine compound is at least one selected from the group consisting of polyethyleneimine and polylysine. <9> Cellulose particles as described above. <11> The wax is carnauba wax. <9> or <10> Cellulose particles as described above. <12> The coating layer comprises a first coating layer that covers the mother particles and contains the polyamine compound, and a second coating layer that covers the first coating layer and contains the wax. <9> ~ <11> Cellulose particles as described in any one of the following. <13> The second coating layer further contains a polyvalent metal salt <12> Cellulose particles as described above. <14> At least one external additive selected from the group consisting of silicon-containing compound particles and metal soap particles is added externally. <1> ~ <13> Cellulose particles as described in any one of the following. <15> The silicon-containing compound particles are silica particles. <14> Cellulose particles as described above. <16> The volume-average particle diameter is 3 μm or more and less than 10 μm. <1> ~ <15> Cellulose particles as described in any one of the following. <17> The GSDv (Grain Size Distribution Index) on the larger diameter side is between 1.0 and 1.7. <1> ~ <16> Cellulose particles as described in any one of the following. <18> The sphericity is 0.90 or higher. <1> ~ <17> Cellulose particles as described in any one of the following. <19> The number-average molecular weight of the cellulose is 37,000 or more. <1> ~ <18> Cellulose particles as described in any one of the following. <20> The number-average molecular weight of the cellulose is 45,000 or more. <19> Cellulose particles as described above. <21> The surface smoothness is 80% or higher. <1> ~ <20> Cellulose particles as described in any one of the following. [Effects of the Invention]

[0006] <1> , <6> , or <7> According to the present invention, cellulose particles containing cellulose are provided that are superior in biodegradability and flexibility compared to cases in which at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group together with a long-chain aliphatic group, and a (meth)acrylic acid compound (C). <2> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the content of the first component is less than 70% by mass or more than 95% by mass of the total content of the first and second components. <3> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the total content of the second component is less than 5% by mass or more than 30% by mass relative to the total content of the first and second components. <4> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the fatty acid derivative (A) is a fatty acid derivative having fewer than 10 carbon atoms or more than 25 saturated aliphatic groups. <5> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the octanol / water partition coefficient of a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms is less than 5 or greater than 10.

[0007] <8> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the octanol / water partition coefficient of the aromatic compound (B0) is less than 5 or greater than 20. <9> , or <10> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to single-layer cellulose particles mainly composed of cellulose. <11> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the wax is diisostearyl malate. <12> According to the invention, cellulose particles are provided that have superior biodegradability and flexibility compared to cases where the coating layer covers the mother particles and has only a first coating layer containing a polyamine compound. <13> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to the case in which the second coating layer does not contain polyvalent metal salts. <14> , or <15> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where fatty acid ester particles or stearyl stearate particles are added externally.

[0008] <16> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the volume average particle diameter is less than 3 μm or greater than 10 μm. <17> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the large diameter side particle size distribution index GSDv is less than 1.0 or greater than 1.7. <18> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the sphericity is less than 0.90. <19> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the number-average molecular weight of cellulose is less than 37,000. <20> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the number-average molecular weight of cellulose is less than 45,000. <21> According to the invention, cellulose particles are provided that are superior in biodegradability and flexibility compared to cases where the surface smoothness is less than 80%. [Modes for carrying out the invention]

[0009] The following describes an example embodiment of the present invention. These descriptions and examples are illustrative and do not limit the scope of the invention. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0010] Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition.

[0011] <Cellulose particles> The cellulose particles according to this embodiment include a first component which is cellulose, and a second component which is at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C).

[0012] The cellulose particles according to this embodiment exhibit excellent biodegradability and flexibility due to the above configuration. The reason for this is presumed to be as follows.

[0013] Cellulose-containing particles (hereinafter referred to as cellulose particles) have the advantage of being highly biodegradable due to their cellulose content. However, cellulose particles tend to become hard due to their cellulose content, which has sometimes limited their applications. To impart flexibility to cellulose particles, it is preferable to use cellulose particles that contain components other than cellulose along with the cellulose itself. However, cellulose tends to have low compatibility with components other than cellulose.

[0014] In contrast, the cellulose particles according to this embodiment contain, along with a first component which is cellulose, a second component which is more flexible than cellulose (i.e., at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a long-chain aliphatic group, a phenolic hydroxyl group, and a monoglycidyl ether group directly bonded to an aromatic group, and a (meth)acrylic acid compound (C)). Although not certain, it is thought that a sea-island structure, consisting of a sea portion made of the first component and an island portion made of the second component, is likely to form in the cellulose particles. Furthermore, the first and second components have low compatibility, and the size of the island region made of the second component tends to be large. Consequently, the flexibility of the island region tends to greatly influence the flexibility of the cellulose particles. Therefore, it is presumed that the cellulose particles according to this embodiment have excellent flexibility. Furthermore, since the cellulose particles according to this embodiment contain cellulose, they also exhibit excellent biodegradability.

[0015] From the above, it is presumed that the cellulose particles according to this embodiment have excellent biodegradability and flexibility due to the above configuration.

[0016] (Component 1) The cellulose particles according to this embodiment contain a first component which is cellulose. The number-average molecular weight of cellulose is preferably 37,000 or more, and more preferably 45,000 or more. The upper limit of the number-average molecular weight of cellulose is not particularly limited, but it may be, for example, 100,000 or less.

[0017] By setting the number-average molecular weight of cellulose to 37,000 or higher, it becomes easier to produce cellulose particles with superior flexibility. The reason for this is presumed to be as follows: As the molecular weight of cellulose increases, the number of terminal hydroxyl groups decreases, resulting in fewer hydrogen bonds being formed at the ends. This prevents the rigid cellulose molecular chain from becoming too long, thus imparting flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0018] Furthermore, by setting the number-average molecular weight of cellulose to 37,000 or higher, it is easier to obtain cellulose particles that are highly biodegradable and maintain their flexibility over time. By setting the number-average molecular weight of cellulose to 37,000 or higher, the initial biodegradation rate can be more easily suppressed. This makes it easier to suppress chipping of the cellulose particle surface or deformation of the cellulose particles due to biodegradation, resulting in less change in flexibility over time. In addition, the disintegration of cellulose particles due to biodegradation becomes more uniform, and biodegradability is also improved.

[0019] The number-average molecular weight of cellulose is measured using gel permeation chromatography (differential refractometer Optilab T-rEX / Wyatt Technology, multi-angle light scattering detector DAWN HELEOS II / Wyatt Technology, column TSKgel α-M and α-3000, one of each / Tosoh Corporation) with dimethylacetamide (with 0.1M lithium chloride added) as the solvent.

[0020] The content of the first component is preferably 70% by mass or more and 95% by mass or less of the total content of the first and second components. By keeping the content of the first component within the above range, it is easier to obtain cellulose particles that are more biodegradable and flexible. The reason for this is presumed to be as follows. By setting the content of the first component to 70% by mass or more of the total content of the first and second components, the cellulose content in the cellulose particles increases. As a result, the biodegradability of the cellulose particles is more easily improved. Furthermore, by limiting the content of the first component to 95% by mass or less of the total content of the first and second components, the cellulose content in the cellulose particles does not become too high. Therefore, a decrease in the flexibility of the cellulose particles can be suppressed. Based on the above, it is presumed that by keeping the content of the first component within the above range, it is easier to obtain cellulose particles that are more biodegradable and flexible.

[0021] Furthermore, from the viewpoint of obtaining cellulose particles with excellent biodegradability and flexibility, the content of the first component is more preferably 75% by mass or more and 90% by mass or less, and even more preferably 80% by mass or more and 85% by mass or less, relative to the total content of the first and second components.

[0022] From the viewpoint of providing cellulose particles with excellent biodegradability and flexibility, the content of the first component is preferably 75% to 90% by mass, more preferably 80% to 90% by mass, and even more preferably 85% to 90% by mass, relative to the total amount of cellulose particles. However, if the cellulose particles have a coating layer as described later, the content of the first component refers to its content relative to the entire mother particle containing the first and second components on which the coating layer is formed.

[0023] (Second component) The cellulose particles according to this embodiment include a fatty acid derivative (A), a long-chain aliphatic group, an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group, and a (meth)acrylic acid compound (C).

[0024] -Fatty acid derivative (A)- Fatty acid derivative (A) is a compound obtained by reacting the carboxyl group of a fatty acid with another functional group. Other functional groups include, for example, amino groups and hydroxyl groups. In other words, examples of fatty acid derivatives (A) include fatty acid amides and fatty acid esters. Here, fatty acids are defined by the general formula C n H m This refers to compounds that can be represented as COOH (where n and m are integers).

[0025] The fatty acid derivative (A) is preferably a fatty acid derivative having a saturated aliphatic group having 10 to 25 carbon atoms, more preferably a fatty acid derivative having a saturated aliphatic group having 12 to 20 carbon atoms, and even more preferably a fatty acid derivative having a saturated aliphatic group having 14 to 18 carbon atoms.

[0026] By using a fatty acid derivative (A) that has a saturated aliphatic group with 10 to 25 carbon atoms, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. By using a fatty acid derivative (A) that has a saturated aliphatic group with 10 to 25 carbon atoms, the compatibility between cellulose acylate, a raw material used in the production of cellulose particles, and the fatty acid derivative (A) is easily increased. As a result, it is thought that a sea-island structure consisting of a sea portion made up of the first component and an island portion made up of the second component is more easily formed in the cellulose particles, and the size of the island region made up of the second component tends to increase. Based on the above, it is presumed that this will result in cellulose particles that are more flexible.

[0027] The octanol / water partition coefficient (hereinafter also referred to as the O / W coefficient) of a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms is preferably 5 to 10, preferably 6 to 9, and preferably 7 to 8.

[0028] Here, the octanol / water partition coefficient is a value calculated as follows: The sample is dissolved in a mixture of octanol and water in a mass ratio of 1 / 1, and the concentration of the substance in octanol (Co) and the concentration of the substance in water (Cw) are measured. The octanol / water partition coefficient (O / W coefficient) is then calculated using the following formula (1). Equation (1): O / W coefficient = Log(Co / Cw) (In equation (1), "Log" means common logarithm.) The concentration of the substance in octanol (Co) and the concentration of the substance in water (Cw) are measured as follows. The test follows OECD test guidelines. More specifically, the sample is dissolved in a 1:1 mass mixture of 1-octanol and water, centrifuged, and completely separated into two layers. A suitable amount of octanol solution is collected from the 1-octanol layer using a pipette. Air is pre-inhaled into the syringe, and the solution is quickly collected from the aqueous layer by passing it through the 1-octanol layer while expelling the air. For each solution, the test concentration is quantified using an ion chromatograph (Metrohm 930 Compact IC).

[0029] When the octanol / water partition coefficient (O / W coefficient) of a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms is set to 5 to 10, it tends to produce cellulose particles with superior flexibility. The reason for this is presumed to be as follows. When the O / W coefficient of a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms is set to 5 to 10, the compatibility between cellulose acylate, a raw material used in the production of cellulose particles, and the fatty acid derivative (A) tends to increase. Therefore, it is thought that a sea-island structure, consisting of a sea portion made of the first component and an island portion made of the second component, is more easily formed in the cellulose particle, and the size of the island region made of the second component tends to increase. Based on the above, it is presumed that this will result in cellulose particles that are more flexible.

[0030] From the viewpoint of increasing the flexibility of cellulose particles, the fatty acid derivative (A) is preferably a fatty acid amide. The fatty acid amide is preferably a fatty acid amide obtained by amidating a fatty acid and an amine.

[0031] As for the fatty acids used in the synthesis of fatty acid amides, saturated fatty acids are preferred from the viewpoint of increasing the flexibility of cellulose particles, saturated fatty acids having 10 to 25 carbon atoms are more preferred, saturated fatty acids having 15 to 20 carbon atoms are even more preferred, and octacosanoic acid is particularly preferred. Examples of amines used in the synthesis of fatty acid amides include primary amines and secondary amines. From the viewpoint of improving the flexibility of cellulose particles, it is preferable that the amine used in the synthesis of fatty acid amides is an amine having one or more hydroxyl groups (hereinafter also referred to as an amino alcohol). From the viewpoint of improving the flexibility of cellulose particles, it is preferable that the amine used in the synthesis of fatty acid amides has a structure in which an amino group and a hydroxyl group are bonded to a divalent hydrocarbon group. The divalent hydrocarbon group preferably has 1 to 10 carbon atoms, and more preferably 2 to 5 carbon atoms. Examples of ethanolamines used in the synthesis of fatty acid amides include methanolamine, ethanolamine, 3-amino-1-propanol, 4-amino-1-butanol, and diethanolamine.

[0032] The fatty acid derivative (A) is preferably a fatty acid amide (hereinafter also referred to as a fatty acid ethanolamide) obtained by amidating a fatty acid and an amino alcohol.

[0033] Using fatty acid ethanolamide as the fatty acid derivative (A) tends to result in cellulose particles with superior flexibility. The reason for this is presumed to be as follows. By using fatty acid ethanolamide as the fatty acid derivative (A), the compatibility between cellulose acylate, a raw material used in the production of cellulose particles, and the fatty acid derivative (A) is easily increased. Therefore, it is thought that a sea-island structure consisting of a sea portion made up of the first component and an island portion made up of the second component is more easily formed in the cellulose particles, and the size of the island region made up of the second component tends to increase. Based on the above, it is presumed that this will result in cellulose particles that are more flexible.

[0034] Specifically, the fatty acid ethanolamide is preferably a compound represented by the following formula (A-1).

[0035] [ka]

[0036] In formula (A-1), R1 is the residue obtained by removing the carboxyl group from a fatty acid, and is preferably a saturated aliphatic group having 10 to 25 carbon atoms, and more preferably a saturated aliphatic group having 15 to 20 carbon atoms. Furthermore, R2 and R3 represent the residue obtained by removing one amino group from ethanolamine. R2 and R3 are preferably a hydrocarbon group having a hydrogen atom or a hydroxyl group, respectively. The number of carbon atoms in the hydrocarbon group having a hydroxyl group is preferably 1 to 10, and more preferably 2 to 5. R2 and R3 may be the same or different.

[0037] -Aromatic compound (B)- This section describes aromatic compounds (B) (hereinafter also simply referred to as "aromatic compounds (B)") which have at least one of a long-chain aliphatic group, a phenolic hydroxyl group, and a monoglycidyl ether group directly bonded to an aromatic group.

[0038] The long-chain aliphatic group is preferably an aliphatic group having 8 to 20 carbon atoms (or 10 to 18 carbon atoms). In other words, the aromatic compound (B) is preferably an aromatic compound (B0) (hereinafter also simply referred to as "aromatic compound (B0)") which has an aliphatic group having 8 to 20 carbon atoms (or 10 to 18 carbon atoms), a phenolic hydroxyl group, and at least one of a monoglycidyl ether group directly bonded to the aromatic group.

[0039] Long-chain aliphatic groups include saturated aliphatic groups (alkyl groups) and unsaturated aliphatic groups (alkenyl groups, alkynyl groups) having 8 to 20 carbon atoms (preferably 10 to 20 carbon atoms). The aliphatic group may be linear, branched, or cyclic, but linear and branched are preferred, and linear is more preferred.

[0040] By using aromatic compound (B0) as aromatic compound (B), it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. By using aromatic compound (B0) as aromatic compound (B), the compatibility between cellulose acylate, a raw material used in the production of cellulose particles, and aromatic compound (B) is easily increased. Therefore, it is thought that a sea-island structure consisting of a sea portion made of the first component and an island portion made of the second component is more easily formed in the cellulose particles, and the size of the island region made of the second component tends to increase. Based on the above, it is presumed that this will result in cellulose particles that are more flexible.

[0041] The octanol / water partition coefficient of the aromatic compound (B0) is preferably 5 to 20, more preferably 7 to 18, and even more preferably 10 to 15. The procedure for calculating the octanol / water partition coefficient is as previously described.

[0042] Setting the O / W coefficient of the aromatic compound (B0) to between 5 and 20 tends to result in more flexible cellulose particles. The reason for this is presumed to be as follows. Setting the O / W coefficient of the aromatic compound (B0) to between 5 and 20 tends to increase the compatibility between cellulose acylate, a raw material used in the production of cellulose particles, and the aromatic compound (B). Therefore, it is thought that a sea-island structure, consisting of a sea portion made of the first component and an island portion made of the second component, is more easily formed in the cellulose particles, and the size of the island region made of the second component tends to increase. Based on the above, it is presumed that this will result in cellulose particles that are more flexible.

[0043] Aromatic compounds (B) include compounds in which a phenolic hydroxyl group is substituted along with a long-chain aliphatic group in monocycles, fused rings (polycycles having two or more aromatic rings), polynuclear rings (polycycles in which aromatic rings are linked by carbon-carbon bonds), and heterocycles (monocycles of heterocycles, fused rings containing heterocycles, polynuclear rings containing heterocycles, etc.).

[0044] Examples of aromatic compounds (B) include cardanol compounds, phenalkamine compounds, phenol resins, phenol novolac type epoxy resins, phenol resol type epoxy resins, phenol-modified palm oil, phenol-modified soybean oil, and phenol-modified linseed oil.

[0045] From the viewpoint of obtaining cellulose particles with excellent biodegradability and flexibility, cardanol compound (D1) is preferred as aromatic compound (B). Cardanol compounds (D1) refer to components contained in naturally derived compounds made from cashews (for example, compounds represented by the following structural formulas (d-1) to (d-4)) or derivatives of said components.

[0046] [ka]

[0047] The cardanol compound (D1) may also be a mixture of naturally derived compounds using cashews as a raw material (hereinafter also referred to as "cashew-derived mixture").

[0048] The cardanol compound (D1) may also be a derivative from a cashew-derived mixture. Examples of derivatives from cashew-derived mixtures include the following mixtures and individual compounds.

[0049] • A mixture in which the composition ratio of each component in a cashew-derived mixture has been adjusted. • Elemental components isolated from a cashew-derived mixture. • A mixture containing a modified product in which the components of the cashew-derived mixture have been altered. • A mixture containing polymers obtained by polymerizing components from a cashew-derived mixture. • A mixture containing a modified polymer obtained by modifying and polymerizing components in a cashew-derived mixture. • A mixture containing a modified body, which is obtained by further modifying the components of the mixture whose composition ratio has been adjusted. • A mixture containing a polymer obtained by further polymerizing the components in the mixture whose composition ratio has been adjusted. • A mixture containing a modified polymer obtained by further modifying and polymerizing the components of the mixture whose composition ratio has been adjusted. • Modified bodies obtained by further modifying the isolated element described above. • Polymers obtained by further polymerizing the isolated element. • Modified polymer obtained by further modifying and polymerizing the isolated element. Here, the term "elementary substance" includes macromers such as dimers and trimers.

[0050] From the viewpoint of improving the biodegradation rate of cellulose particles, the cardanol compound (D1) is preferably at least one compound selected from the group consisting of compounds represented by general formula (CDN1) and polymers obtained by polymerizing compounds represented by general formula (CDN1).

[0051] [ka]

[0052] In the general formula (CDN1), R 1 R represents an alkyl group which may have substituents, or an unsaturated aliphatic group which has a double bond and may have substituents. 2 R represents a hydroxyl group, a carboxyl group, an optionally substituted alkyl group, or an optionally substituted unsaturated aliphatic group having a double bond. P2 represents an integer between 0 and 4. When P2 is 2 or greater, there are multiple R groups. 2 These may be the same group or different groups.

[0053] In the general formula (CDN1), R 1The alkyl group which may have substituents represented by is preferably an alkyl group having 3 to 30 carbon atoms, more preferably an alkyl group having 5 to 25 carbon atoms, and even more preferably an alkyl group having 8 to 20 carbon atoms. Examples of substituents include hydroxyl groups; substituents containing ether bonds such as epoxy groups and methoxy groups; substituents containing ester bonds such as acetyl groups and propionyl groups; and so on. Examples of alkyl groups that may have substituents include pentadecane-1-yl, heptane-1-yl, octan-1-yl, nonane-1-yl, decane-1-yl, undecane-1-yl, dodecane-1-yl, and tetradecane-1-yl groups.

[0054] In the general formula (CDN1), R 1 The unsaturated aliphatic group having a double bond and which may have substituents is preferably an unsaturated aliphatic group having 3 to 30 carbon atoms, more preferably an unsaturated aliphatic group having 5 to 25 carbon atoms, and even more preferably an unsaturated aliphatic group having 8 to 20 carbon atoms. The number of double bonds in the unsaturated aliphatic group is preferably between 1 and 3. Examples of substituents include those listed above as substituents of alkyl groups. Examples of unsaturated aliphatic groups having a double bond and which may have substituents include pentadeca-8-en-1-yl group, pentadeca-8,11-dien-1-yl group, pentadeca-8,11,14-trien-1-yl group, pentadeca-7-en-1-yl group, pentadeca-7,10-dien-1-yl group, and pentadeca-7,10,14-trien-1-yl group.

[0055] In the general formula (CDN1), R 1Examples thereof include a pentadeca-8-en-1-yl group, a pentadeca-8,11-dien-1-yl group, a pentadeca-8,11,14-trien-1-yl group, a pentadeca-7-en-1-yl group, a pentadeca-7,10-dien-1-yl group, and a pentadeca-7,10,14-trien-1-yl group.

[0056] In the general formula (CDN1), R 2 Examples of the alkyl group which may have a substituent represented by and the unsaturated aliphatic group which has a double bond and may have a substituent include those exemplified as the alkyl group which may have a substituent represented by the above R 1 and the unsaturated aliphatic group which has a double bond and may have a substituent, and are preferably the same.

[0057] The compound represented by the general formula (CDN1) may be further modified. For example, it may be epoxidized. Specifically, it may be a compound having a structure in which the hydroxy group possessed by the compound represented by the general formula (CDN1) is replaced with the following group (EP), that is, a compound represented by the following general formula (CDN1-e).

[0058] [Chemical formula]

[0059] In the group (EP) and the general formula (CDN1-e), L EP represents a single bond or a divalent linking group. In the general formula (CDN1-e), R 1 , R 2 and P2 are respectively synonymous with R 1 , R 2 and P2 in the general formula (CDN1).

[0060] In the group (EP) and the general formula (CDN1-e), examples of the divalent linking group represented by LEP include an alkylene group which may have a substituent (preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 1 carbon atom), a -CH2CH2OCH2CH2- group, and the like. The substituents mentioned above include R of the general formula (CDN1). 1 The substituents listed in the above are similarly included.

[0061] A methylene group is preferred as the LEP.

[0062] A polymer obtained by polymerizing compounds represented by the general formula (CDN1) refers to a polymer obtained by polymerizing at least two or more compounds represented by the general formula (CDN1), with or without the use of linking groups.

[0063] Examples of polymers obtained by polymerizing compounds represented by the general formula (CDN1) include the compound represented by the following general formula (CDN2).

[0064] [ka]

[0065] In the general formula (CDN2), R 11 , R 12 and R 13 Each of these independently represents an optionally substituted alkyl group or an optionally substituted unsaturated aliphatic group having a double bond. 21 , R 22 and R 23 Each of these independently represents a hydroxyl group, a carboxyl group, an optionally substituted alkyl group, or an optionally substituted unsaturated aliphatic group having a double bond. P21 and P23 each independently represent an integer between 0 and 3, and P22 represents an integer between 0 and 2. 1 and L 2 Each of these independently represents a divalent linking group. n represents an integer between 0 and 10 (inclusive). There are multiple R groups when P21 is 2 or greater. 21 When P22 is 2 or more, there are multiple R 22 , and when P23 is 2 or more, there are multiple R 23 Each of these may be the same group or different groups. When n is 2 or greater, there may be multiple R 12 , R22 and L 1 Each of these may be the same group or different groups, and if there are multiple P22s when n is 2 or greater, they may be the same number or different numbers.

[0066] In the general formula (CDN2), R 11 , R 12 , R 13 , R 21 , R 22 and R 23 The alkyl group which may have substituents represented by and the unsaturated aliphatic group which has a double bond and may have substituents include the R of the general formula (CDN1). 1 The examples listed above are also desirable examples.

[0067] In the general formula (CDN2), L 1 and L 2 Examples of the divalent linking group represented by include alkylene groups which may have substituents (preferably alkylene groups having 2 to 30 carbon atoms, more preferably alkylene groups having 5 to 20 carbon atoms). The substituents mentioned above include R of the general formula (CDN1). 1 The substituents listed in the above are similarly included.

[0068] In the general formula (CDN2), n is preferably between 1 and 10, and more preferably between 1 and 5.

[0069] The compound represented by the general formula (CDN2) may be further modified. For example, it may be epoxidized, and specifically, it may be a compound in which the hydroxyl group of the compound represented by the general formula (CDN2) is replaced by a group (EP), that is, a compound represented by the general formula (CDN2-e) below.

[0070] [ka]

[0071] In the general formula (CDN2-e), R 11 , R 12 , R 13 , R 21 , R 22 , R 23 , P 21 , P 22 , P 23 , L 1 , L 2 and n are R in the general formula (CDN2), respectively. 11 , R 12 , R 13 , R 21 , R 22 , R 23 , P 21 , P 22 , P 23 , L 1 , L 2 This is synonymous with n. In the general formula (CDN2-e), L EP1 , L EP2 and L EP3 Each of these independently represents a single bond or a divalent linking group. When n is 2 or more, there are multiple L EP2 These may be the same group or different groups.

[0072] In the general formula (CDN2-e), L EP1 , L EP2 and L EP3 The divalent linking group represented by is L in the general formula (CDN1-e). EP The divalent linking groups represented by are listed as similarly preferred examples.

[0073] A polymer obtained by polymerizing a compound represented by the general formula (CDN1) may be, for example, a polymer obtained by three or more compounds represented by the general formula (CDN1) being three-dimensionally crosslinked polymerized with or without linking groups. An example of a polymer obtained by three-dimensionally crosslinking polymerizing a compound represented by the general formula (CDN1) is a compound represented by the following structural formula.

[0074] [ka]

[0075] In the above structural formula, R 10 , R 20 P20 and P20 are R in the general formula (CDN1), respectively. 1 , R 2 And it is synonymous with P2. L 10 R represents a single bond or a divalent linking group. There are multiple R's. 10 , R 20 and L 10 Each of these may be the same group or different groups. The multiple P20s may be the same number or different numbers.

[0076] In the above structural formula, L 10 Examples of the divalent linking group represented by include alkylene groups which may have substituents (preferably alkylene groups having 2 to 30 carbon atoms, more preferably alkylene groups having 5 to 20 carbon atoms). The substituents mentioned above include R of the general formula (CDN1). 1 The substituents listed in the above are similarly included.

[0077] The compound represented by the above structural formula may be further modified, for example, by epoxidization. Specifically, it may be a compound in which the hydroxyl group of the compound represented by the above structural formula is replaced by a group (EP), for example, a polymer obtained by three-dimensionally crosslinking polymerization of the compound represented by the following structural formula, i.e., the compound represented by the general formula (CDN1-e).

[0078] [ka]

[0079] In the above structural formula, R 10 , R 20 P20 and P20 are R in the general formula (CDN1-e), respectively. 1 , R 2 And it is synonymous with P2. L 10 R represents a single bond or a divalent linking group. There are multiple R's. 10, R 20 and L 10 may each be the same group or different groups. The plurality of P20 may be the same number or different numbers.

[0080] In the above structural formula, the divalent linking group represented by L 10 includes, for example, an alkylene group which may have a substituent (preferably an alkylene group having 2 to 30 carbon atoms, more preferably an alkylene group having 5 to 20 carbon atoms), and the like. Examples of the above substituents include those listed as substituents in R 1 of the general formula (CDN1). <​​​​​​​​​When using a cardanol compound (D1) having an epoxy group, its epoxy equivalent is preferably 300 to 500, more preferably 350 to 480, and even more preferably 400 to 470, from the viewpoint of improving the transparency of the cellulose particles. The epoxy equivalent of the cardanol compound (D1) having an epoxy group is measured in accordance with ISO 3001.

[0084] The weight-average molecular weight of the cardanol compound (D1) is preferably 250 to 1000, more preferably 280 to 800, and even more preferably 300 to 500, from the viewpoint of improving the heat resistance and flexibility of the cellulose particles. The weight-average molecular weight of cardanol compound (D1) is measured in polystyrene equivalent using a gel permeation chromatography system (GPC system: Tosoh Corporation, HLC-8320GPC, column: TSKgelα-M) with tetrahydrofuran as the eluent.

[0085] Cardanol compounds (D1) may be used individually or in combination of two or more.

[0086] -(meth)acrylic acid-based compounds (C)- (Meth)acrylic acid compound (C) is a polymer whose constituent unit is a monomer selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid derivatives. Here, (meth)acrylic means acrylic or methacrylic.

[0087] (Meth)acrylic acid derivatives are compounds obtained by reacting the carboxyl group of (meth)acrylic acid with other functional groups, and examples include (meth)acrylamide and (meth)acrylic acid ester. As the (meth)acrylic acid derivative, (meth)acrylic acid esters are preferred. (Meth)acrylic acid esters are compounds obtained by esterifying the carboxyl group of (meth)acrylic acid with a compound having a hydroxyl group, and have at least one ester group. Examples of (meth)acrylic acid esters include alkyl (meth)acrylates having 1 to 30 carbon atoms (or 1 to 20 carbon atoms), hydroxyalkyl (meth)acrylates, and glyceryl methacrylate. The (meth)acrylic acid compound (C) may have a crosslinked structure.

[0088] (Meth)acrylic acid compound (C) may contain other monomers other than (meth)acrylic acid and (meth)acrylic acid derivatives as constituent units. Other monomers include, for example, vinylpyrrolidone.

[0089] Examples of (meth)acrylic acid compounds (C) include compounds with the INCI name "ACRYLATES / C10-30 ALKYL ACRYLATE CROSSPOLYMER ((Acrylates / Alkyl Acrylate (C10-30)) Crosspolymer)", compounds with the INCI name "(Acrylates / Ethylhexyl Acrylate / Dimethicone Methacrylate) Copolymer", compounds with the INCI name "(Acrylates / VP) Crosspolymer", compounds with the INCI name "(Acrylates / Hydroxyalkyl Acrylate) Copolymer", compounds with the INCI name "(Acrylates / Alkyl Acrylate (C10-30)) Crosspolymer", compounds with the INCI name "(Acrylates / Alkyl Succinate (C1,2) / Hydroxyalkyl Acrylate) Copolymer", and compounds with the INCI name "Alkyl Polyacrylate (C10-30)".

[0090] -Total content of the second component- The total content of the second component is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, and even more preferably 15% by mass or more and 20% by mass or less, relative to the total content of the first and second components.

[0091] By setting the content of the second component to 5% to 30% by mass relative to the total content of the first and second components, it is easier to obtain cellulose particles that are more biodegradable and flexible. The reason for this is presumed to be as follows. By setting the content of the second component to 5% by mass or more relative to the total content of the first and second components, the size of the island region consisting of the second component tends to increase, improving the flexibility of the cellulose particles. By limiting the content of the second component to 30% by mass or less relative to the total content of the first and second components, the content of the second component in the cellulose particles does not become too high. Therefore, the decrease in the biodegradability of the cellulose particles is suppressed. Based on the above, it is presumed that by keeping the content of the first component within the above range, it is easier to obtain cellulose particles that are more biodegradable and flexible.

[0092] (Cellulose particles with a coating layer) The cellulose particles according to this embodiment are preferably cellulose particles (hereinafter also referred to as "cellulose particles having a coating layer") having a mother particle containing a first component and a second component, and a coating layer covering the mother particle, the coating layer containing at least one selected from the group consisting of polyamine compounds, waxes, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds.

[0093] By using the above configuration for the cellulose particles according to this embodiment, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. Polyamine compounds, or linear saturated fatty acids, tend to adopt a structure in which relatively long linear chains rise outward from the particle surface due to the ionic affinity of their amino or carboxylic acid groups to the hydroxyl groups of cellulose. Hydroxy fatty acids, on the other hand, readily form a sponge-like structure as their hydroxyl groups bond with the hydroxyl groups of cellulose, causing relatively long linear chains to spread outwards at an angle from the hydroxyl group, intertwining with each other. This higher-order structure of the coating layer allows for excellent flexibility when external forces are applied, as the deformation of the higher-order structure absorbs the force. Waxes and amino acid-based compounds self-aggregate on the cellulose surface, easily forming flat, island-like coatings with appropriate gaps on the particle surface. We believe that this island-like structure allows for high force absorption even in small amounts, resulting in excellent flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0094] -Mother particle- The parent particle contains a first component and a second component. The first and second components contained in the mother particles are the same as the first and second components described above, and the preferred ranges are also the same.

[0095] -Coating layer- The coating layer contains at least one selected from the group consisting of polyamine compounds, waxes, linear saturated fatty acids, hydroxy fatty acids, and amino acid-based compounds.

[0096] • Polyamine compounds Polyamine compounds are a general term for aliphatic hydrocarbons that have two or more primary amino groups. Examples of polyamine compounds include polyalkyleneimines, polyallylamines, polyvinylamines, and polylysine. As for the polyalkylene imine, from the viewpoint of improving biodegradability, polyalkylene imines having constituent units with alkylene groups having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms) are preferred, and polyethyleneimine is more preferred. Examples of polyallylamines include homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, and dimethylallylamine. Examples of polyvinylamines include those produced by hydrolyzing poly(N-vinylformamide) with an alkali, specifically "PVAM-0595B" manufactured by Mitsubishi Chemical Corporation. Polylysine may be extracted from natural products, produced by transformed microorganisms, or chemically synthesized.

[0097] It is preferable that the polyamine compound is at least one selected from the group consisting of polyethyleneimine and polylysine. By applying at least one polyamine compound selected from the group consisting of polyethyleneimine and polylysine, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. Among polyamine compounds, polyethyleneimine and polylysine have high cationic properties and a stronger affinity for cellulose hydroxyl groups. Therefore, they adsorb strongly to cellulose particles and are less likely to detach during manufacturing and use, resulting in superior flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0098] The polyamine compound content is preferably 0.2% by mass or more and 2% by mass or less relative to the total amount of cellulose particles.

[0099] ·wax Examples of waxes include vegetable oils containing fatty acids, hydrocarbon waxes, and diesters. Examples of vegetable oils containing fatty acids include castor oil, tung oil, linseed oil, shortening, corn oil, soybean oil, sesame oil, rapeseed oil, sunflower oil, rice oil, camellia oil, coconut oil, palm oil, walnut oil, olive oil, peanut oil, almond oil, jojoba oil, cocoa butter, shea butter, neem oil, safflower oil, wood wax, candelilla wax, rice wax, carnauba wax, and damask rose flower wax. Examples of hydrocarbon waxes include petroleum waxes (paraffin wax, microcrystalline wax, petrolatum wax, etc.) and synthetic hydrocarbon waxes (polyethylene wax, polypropylene wax, polybutene wax, Fischer-Tropsch wax, etc.). Examples of diesters include diesters of dibasic acids such as malic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanediic acid, and alcohols having 10 to 25 carbon atoms.

[0100] Carnauba wax is preferred as the wax. Applying carnauba wax as the wax makes it easier to create cellulose particles with superior flexibility. The reason for this is presumed to be as follows: Carnauba wax contains fatty acids as its components. The terminal carboxylic acids of fatty acids have a high affinity for the hydroxyl groups of cellulose, resulting in strong adsorption to the particle surface and resistance to detachment during manufacturing and use. Therefore, it can exhibit superior flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0101] The wax content is preferably 0.1% by mass or more and 2% by mass or less, and more preferably 0.2% by mass or more and 1% by mass or less, relative to the total amount of cellulose particles.

[0102] • Straight-chain saturated fatty acids Straight-chain saturated fatty acids are saturated fatty acids that have a linear structure. As for the linear saturated fatty acid, it is preferable that it be a linear saturated fatty acid with 14 to 22 carbon atoms, from the viewpoint of obtaining cellulose particles with superior flexibility or superior biodegradability. Examples of straight-chain saturated fatty acids with 14 to 22 carbon atoms include behenic acid, arachidic acid, and palmitic acid.

[0103] The linear saturated fatty acid content is preferably 2% by mass or more and 15% by mass or less, and more preferably 5% by mass or more and 10% by mass or less, relative to the total amount of cellulose particles.

[0104] • Hydroxy fatty acids Hydroxy fatty acids are fatty acids that contain a hydroxyl group. Examples of hydroxy fatty acids include those with 14 to 20 carbon atoms. Examples of hydroxy fatty acids with 14 to 20 carbon atoms include hydroxystearic acid, hydroxypaltimic acid, and hydroxymyristic acid.

[0105] The hydroxy fatty acid content is preferably 1% by mass or more and 10% by mass or less, relative to the total cellulose particles, and more preferably 3% by mass or more and 10% by mass or less.

[0106] • Amino acid compounds Amino acid compounds refer to amino acids and amino acid derivatives. An amino acid derivative is a compound in which one or more hydrogen atoms or functional groups contained in an amino acid are replaced by other substituents. As for the amino acid-based compound, an amino acid derivative is preferred. Examples of amino acid derivatives include lauroyl lysine, laurylarginine, and myristylleucine.

[0107] The content of amino acid compounds is preferably 2% by mass or more and 10% by mass or less relative to the total amount of cellulose particles.

[0108] • Layer structure of the coating layer The coating layer may include a first coating layer that coats the mother particles and contains at least one selected from the group consisting of polyamine compounds, polyvinyl alcohol, polyvinylpyrrolidone, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds, and a second coating layer that coats the first coating layer and contains wax.

[0109] In particular, it is preferable that the coating layer comprises a first coating layer that coats the mother particles and contains at least one selected from the group consisting of polyamine compounds, linear saturated fatty acids, and hydroxy fatty acids, and a second coating layer that coats the first coating layer and contains wax. The coating layer, having both the first coating layer and the second coating layer, tends to produce cellulose particles with superior flexibility. The reason for this is presumed to be as follows. As described above, polyamine compounds, linear saturated fatty acids, and hydroxy fatty acids all have an affinity for the hydroxyl groups of cellulose and are adsorbed onto the particle surface. Their relatively long linear structures are either facing outwards or entangled on the particle surface. When carnauba wax is applied to this, the carnauba wax self-aggregates on the surface of the first layer, forming island structures. These flexible islands are created on the cushion formed by the first layer, resulting in superior flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0110] • Polyvalent metal salts The second coating layer preferably contains a polyvalent metal salt. The second coating layer, by containing polyvalent metal salts, tends to form cellulose particles with superior flexibility. The reason for this is presumed to be as follows: The wax contained in the second layer has poor adhesion to the layer below. Therefore, it tends to develop coating defects due to self-aggregation. By including a polyvalent metal salt along with the wax in the second coating layer, the polyvalent metal salt adheres almost uniformly to the entire wax, and from that point, almost uniform aggregation occurs over a wide area. This suppresses the occurrence of coating defects due to self-aggregation and improves the adhesion of the second coating layer. Furthermore, when the adhesion of the second coating layer is improved, the flexibility of the cellulose particles tends to improve. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0111] A polyvalent metal salt is a compound composed of two or more valent metal ions and anions. Examples of metal ions with a valency of 2 or higher that constitute polyvalent metal salts include ions of calcium, magnesium, copper, nickel, zinc, barium, aluminum, titanium, strontium, chromium, cobalt, and iron. Anions that constitute polyvalent metal salts include inorganic ions and organic ions. Examples of inorganic ions include chloride ions, bromide ions, iodide ions, nitrate ions, sulfate ions, hydroxide ions, etc. Examples of organic ions include organic acid ions, such as carboxylate ions.

[0112] Examples of polyvalent metal salts include aluminum sulfate, polyaluminum chloride, iron chloride, and calcium hydroxide.

[0113] The content of polyvalent metal salts relative to the wax content is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 5% by mass or less, and even more preferably 0.3% by mass or more and 1% by mass or less.

[0114] • Content of components in the first and second coating layers The total content of polyamine compounds, polyvinyl alcohol, polyvinylpyrrolidone, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds relative to the entire first coating layer is preferably 90% by mass or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less. The total content of wax and polyvalent metal salts relative to the entire second coating layer is preferably 90% by mass or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less.

[0115] -External additives- The cellulose particles according to this embodiment may have at least one external additive selected from the group consisting of silicon-containing compound particles, metal soap particles, amino acid-based compound particles, fatty acid ester particles, metal oxide particles, and hydroxy fatty acid particles.

[0116] In particular, it is preferable that the cellulose particles according to this embodiment are externally supplemented with at least one additive selected from the group consisting of silicon-containing compound particles and metal soap particles. The cellulose particles according to this embodiment tend to become more flexible due to the addition of the above-mentioned external additive. The reason for this is presumed to be as follows. Silicon-containing compound particles adhere to cellulose particles via electrostatic charge. At this time, since the silicon-containing compound particles are softer than the cellulose particles, when an external force is applied, the silicon-containing particles deform first, resulting in flexibility. With conventional cellulose particles, flexibility is limited to the particle size of the silicon-containing particles because they do not deform due to their hardness. However, the cellulose particles in this embodiment are also flexible, so when the silicon compound deforms to a certain extent, the cellulose particles deform next. As a result, excellent flexibility is achieved. Metal soap particles partially fuse to and adhere to cellulose particles, but are slightly softer than cellulose particles, exhibiting superior flexibility for the same reason as silicon-containing particles. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0117] Silicon-containing compound particles refer to particles that contain silicon. The silicon-containing compound particles may be particles containing only silicon, or particles containing silicon and other elements.

[0118] The silicon-containing compound particles are preferably silica particles. Silica particles can be any particles whose main component is silica, i.e., SiO2, and may be crystalline or amorphous. Furthermore, silica particles may be particles manufactured using silicon compounds such as water glass or alkoxysilane as raw materials, or particles obtained by crushing quartz.

[0119] By using silica particles as silicon-containing compound particles, it is easier to obtain cellulose particles that are more flexible. The reason for this is presumed to be as follows: Silica particles exhibit particularly strong electrostatic adhesion to cellulose particles among silicon-containing compound particles. Therefore, they are less likely to slip and detach when external forces are applied, resulting in superior flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0120] Metal soap particles are particles whose main component is metal soap. Here, particles whose main component is metal soap refer to particles in which the metal soap content is 90% by mass or more of the total particle size.

[0121] Metallic soaps are fatty acid metal salts formed by the bonding of fatty acids with metals. Examples of fatty acid metal salts include metal salts of fatty acids having 10 to 25 carbon atoms (preferably 12 to 22 carbon atoms). Examples of fatty acid metal salts having 10 to 25 carbon atoms include metal salts of stearic acid, palmitic acid, lauric acid, oleic acid, linoleic acid, and ricinoleic acid. Examples of metals in fatty acid metal salts include divalent metals. Examples of metals in fatty acid metal salts include magnesium, calcium, aluminum, barium, and zinc.

[0122] Fatty acid ester particles are particles whose main component is fatty acid ester particles. Here, particles whose main component is fatty acid ester particles refer to particles in which the content of fatty acid ester particles relative to the total particle is 90% by mass or more.

[0123] Examples of fatty acid esters include esterified products of saturated fatty acids having 10 to 25 carbon atoms and alcohols having 10 to 25 carbon atoms. Examples of fatty acid esters include stearyl stearate, stearyl laurate, and stearyl palmitate.

[0124] Metal oxide particles are particles whose main component is a metal oxide. Here, particles whose main component is metal oxide refer to particles in which the metal oxide content is 90% by mass or more of the total particle size.

[0125] As for metal oxides, oxides of metals other than silicon can be used. Examples of metal oxides include zinc oxide, magnesium oxide, iron oxide, aluminum oxide, and calcium oxide.

[0126] The amount of external additive added is preferably 0.01% by mass or more and 2% by mass or less, relative to the total mass of cellulose particles (cellulose particles without external additive).

[0127] (Volume-average particle size and large-diameter particle size distribution index GSDv) The volume-average particle diameter of the cellulose particles according to this embodiment is preferably 3 μm or more and less than 10 μm, more preferably 4 μm or more and 9 μm or less, and even more preferably 5 μm or more and 8 μm or less.

[0128] By setting the volume-average particle diameter of the cellulose particles according to this embodiment to 3 μm or more and less than 10 μm, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. When the volume-average particle diameter of cellulose particles is 3 μm or more, the amount of deformation that can be physically performed in response to external forces increases, and the effect of exhibiting flexibility tends to improve. On the other hand, since the cellulose particles according to this embodiment have particularly excellent surface flexibility, when the volume-average particle diameter of cellulose particles is 10 μm or less, the volume ratio of the core to the surface decreases, and the effect of exhibiting flexibility tends to improve. Therefore, when the volume-average particle size of cellulose particles is between 3 μm and 10 μm, the amount of deformation is sufficient, and the volume ratio of the surface is also high, making it easy to exhibit excellent flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0129] In this embodiment, the GSDv (Grain Size Distribution Index) for the number of large-diameter cellulose particles is preferably 1.0 or more and 1.7 or less, more preferably 1.0 or more and 1.5 or less, and even more preferably 1.0 or more and 1.3 or less.

[0130] By setting the GSDv (Grain Size Distribution Index) of the large-diameter side of the cellulose particles in this embodiment to 1.0 or more and 1.7 or less, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. When GSDv is set to 1.7 or less, the number and proportion of fine and coarse particles decrease, particle deformation tends to increase, particles with a high surface volume ratio are present, and the flexibility effect tends to be enhanced. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0131] The volume-average particle size and the large-diameter particle size distribution index (GSDp) of cellulose particles are measured as follows: The particle size is measured using the LS particle size distribution analyzer "Beckman Coulter LS13 320 (manufactured by Beckman Coulter)," and the cumulative particle size distribution is plotted from the smallest diameter side on a volume basis. The particle size at which the cumulative distribution reaches 50% is determined as the volume-average particle size. On the other hand, the cumulative particle size distribution is plotted from the smallest diameter side based on volume, and the particle size at which the cumulative distribution reaches 50% is defined as the number-average particle size D50v, and the particle size at which the cumulative distribution reaches 84% ​​is defined as the number-particle size D84v. Then, the large-diameter side number-particle size distribution index GSDv is given by the formula GSDv=(D84v / D50v) 1 / 2 It is calculated as follows.

[0132] (Sphericity) The sphericity of the cellulose particles according to this embodiment is preferably 0.90 or higher, more preferably 0.95 or higher, and even more preferably 0.97 or higher.

[0133] By setting the sphericity of the cellulose particles according to this embodiment to 0.90 or higher, it is easier to obtain cellulose particles with superior flexibility. The reason for this is presumed to be as follows. Cellulose is a crystalline polymer, and crystallization is more likely to occur where there are protrusions on the particle surface. Furthermore, the higher the degree of crystallinity, the harder the cellulose particles become. By achieving a sphericity of 0.90 or higher, the area proportion of the protrusions is reduced, resulting in excellent flexibility. Based on the above, it can be inferred that this process is likely to result in cellulose particles with superior flexibility.

[0134] Sphericity is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the cellulose particles to be measured are collected by suction, a flattened flow is formed, and a still image of the particles is captured by instantaneous strobe flashing. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the sphericity is 3500. If the cellulose particles contain external additives, the cellulose particles to be measured are dispersed in water containing a surfactant, and then ultrasonically treated to remove the external additives. These cellulose particles are then used as the target for measurement.

[0135] (Surface smoothness) The surface smoothness of the cellulose particles according to this embodiment is preferably 80% or more, more preferably 82% to 99%, and even more preferably 84% to 98%.

[0136] By setting the surface smoothness of the cellulose particles according to this embodiment to 80% or more, it is easier to obtain cellulose particles that are more biodegradable and flexible. The reason for this is presumed to be as follows. By achieving a surface smoothness of 80% or more, the number of surface protrusions is reduced. As a result, the repulsive force against external stress in the areas originating from surface protrusions decreases, making it easier to improve flexibility. In addition, because contact with microorganisms becomes more uniform, biodegradation proceeds more uniformly on the surface of cellulose particles, making it easier to improve biodegradability. Based on the above, it is presumed that this will easily result in cellulose particles that are more biodegradable and flexible.

[0137] Surface smoothness is measured using the following procedure. The smoothness M of individual cellulose particles is calculated using the following formula by observing SEM images (magnification 5,000x) of cellulose particles taken with a scanning electron microscope (SEM). The arithmetic mean of the smoothness M of 10 or more arbitrarily selected cellulose particles is then defined as the surface smoothness. The closer the smoothness M value is to 1, the smoother the surface of the cellulose particle is. M = (1 - (S3) / (S2)) × 100 In the above formula, S2 represents the area (projected area) occupied by the cellulose particles in the image, and S3 represents the sum of "the area outside the outline of the circle with the same projected area as S2, and inside the outline of the cellulose particles in the image" and "the area inside the outline of the circle with the same projected area as S2, and outside the outline of the cellulose particles in the image" when the cellulose particles in the image and a circle with the same projected area as S2 are superimposed. The method for superimposing the cellulose particles in the image with a circle having the same projected area as S2 is as follows. When superimposing a circle with the same projected area as S2 onto a cellulose particle in an image, the two images are superimposed in such a way that the area of ​​the overlapping region (the area inside the outline of the circle with the same projected area as S2, and inside the outline of the cellulose particle in the image) is maximized.

[0138] <Method for producing cellulose particles> A method for producing cellulose particles preferably includes a step of producing a particle precursor containing cellulose acylate and a second component (particle precursor production step) and a step of saponifying the cellulose acylate contained in the particle precursor (saponification step).

[0139] -Particle precursor manufacturing process- A particle precursor is produced by any of the following methods (1) to (5): cellulose acylate and a second component (at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group together with a long-chain aliphatic group, and a (meth)acrylic acid compound (C)).

[0140] (1) A kneading and grinding method in which each component is kneaded, the resulting kneaded material is ground and classified to obtain granular material. (2) Dry manufacturing method in which granular material obtained by the kneading and grinding method is changed in shape by mechanical impact force or thermal energy to obtain granular material. (3) Coagulation and coagulation method: Mixing particle dispersions of each component, agglomerating and heating the particles in the dispersion to obtain granular material. (4) Dissolution suspension method: The organic solvent in which each component is dissolved is suspended in an aqueous solvent to granulate a granular material containing each component. (5) A kneading and dissolving method in which each component and a binder are kneaded together, extruded to form pellets, and the resulting pellets are granulated by stirring them in a solvent that dissolves only the binder.

[0141] Here, each component described in (1) to (5) above refers to a component comprising cellulose acylate and at least one selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C).

[0142] Here, cellulose acylate is a cellulose derivative in which at least one of the hydroxyl groups in cellulose is replaced (acylated) with an aliphatic acyl group. Specifically, at least one of the hydroxyl groups in cellulose is -CO-R AC (R AC represents an aliphatic hydrocarbon group. ) This is a cellulose derivative substituted with ).

[0143] -Saponification process- Next, the cellulose acylate contained in the particle precursor is saponified. Through this process, the aliphatic acyl groups in cellulose acylate are hydrolyzed, and cellulose is converted back into cellulose.

[0144] The saponification process is carried out, for example, by adding sodium hydroxide to a dispersion of particle precursors and stirring the dispersion.

[0145] -Coating layer formation process- When producing cellulose particles having a coating layer, it is preferable to include a step of forming the coating layer (coating layer formation step) after the saponification step. In this process, when forming a coating layer, the particles obtained through the saponification process are used as the base particles to form the coating layer.

[0146] First, prepare an aqueous dispersion in which the mother particles are dispersed. Before preparing the aqueous dispersion, it is advisable to acid wash the mother particles.

[0147] Next, the aqueous dispersion containing the mother particles is mixed with an aqueous solution containing the compounds that constitute the first coating layer. This causes a reaction between, for example, the hydroxyl groups of the resin contained in the mother particles and the amine sites and carboxylic acid sites of the surface treatment polymer, forming the first coating layer. Then, the aqueous dispersion containing the mother particles with the first coating layer is mixed with an emulsion containing the compounds that constitute the second coating layer. This forms the second coating layer. Then, cellulose particles having a coating layer are extracted from the mixture. The extraction of cellulose particles having a coating layer is carried out, for example, by filtering the mixture. The extracted cellulose particles having a coating layer are preferably washed with water. This removes any unreacted surface treatment polymer. Then, the cellulose particles according to this embodiment are obtained by drying the cellulose particles having a coating layer. -External addition process- External additives may be added to the obtained cellulose particles. External additive processes include, for example, adding external additives to cellulose particles using a mixing mill, V-type blender, Henschel mixer, or Rejdigge mixer.

[0148] By producing cellulose particles according to this embodiment through the above process, it becomes easier to obtain cellulose particles with excellent biodegradability and flexibility. The reason for this is not entirely clear, but it is presumed to be as follows. The second component tends to be compatible with cellulose acylate in a certain amount. Therefore, the resin particle precursor obtained in the above resin particle precursor manufacturing process is in a state where cellulose acylate and the second component are compatible in a certain amount. Consequently, when the cellulose acylate is changed to cellulose in the subsequent saponification process, the compatibility with the second component decreases, making it easier for a sea-island structure to form in the cellulose particle, consisting of a sea portion made of the first component and an island portion made of the second component. From the above, it is presumed that by producing cellulose particles according to this embodiment through the above process, it becomes easier to obtain cellulose particles with excellent biodegradability and flexibility.

[0149] <Application> Applications of the cellulose particles according to this embodiment include cosmetics, rolling agents, abrasives, scrubbing agents, display spacers, bead molding materials, light diffusing particles, resin reinforcing agents, refractive index control agents, biodegradation accelerators, fertilizers, water-absorbing particles, toner particles, and antiblocking particles in granular form.

[0150] The cellulose particles according to this embodiment are preferably used in cosmetics. In particular, cosmetic additives are preferred as the primary use of cellulose particles according to this embodiment. Because the cellulose particles according to this embodiment have excellent flexibility, when used as a cosmetic additive, they tend to spread well on the skin when the cosmetic is applied to the skin.

[0151] The cellulose particles according to this embodiment can be used as cosmetic additives in, for example, base makeup cosmetics (e.g., makeup base, concealer, foundation, face powder, etc.); makeup cosmetics (e.g., lipstick, gloss, lip liner, blush, eyeshadow, eyeliner, mascara, eyebrow products, nail products, nail care cosmetics, etc.); and skincare cosmetics (e.g., facial cleansers, makeup removers, lotions, emulsions, serums, packs, face masks, eye and lip care cosmetics, etc.). In particular, from the viewpoint of requiring flexibility and biodegradability, the resin particles according to this embodiment are preferably used as cosmetic additives in makeup cosmetics. [Examples]

[0152] Examples are described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0153] <Preparation of each ingredient> I prepared the following materials.

[0154] (Cellulose acylate) Cel1: Daicel "L-20", cellulose acetate, number average molecular weight 47,000. • Cel2: Daicel "L-50", cellulose acetate, number average molecular weight 58,000. Cel3: Eastman Chemical "CAP482-20", cellulose acetate propionate, number average molecular weight 75,000. • Cel4: Eastman Chemical "CAB381-20", cellulose acetate butyrate, number average molecular weight 70,000. Cel5: Eastman Chemical "CA398-6", cellulose acetate, number average molecular weight 35,000. Cel6: Eastman Chemical "CAP482-0.5", cellulose acetate propionate, number average molecular weight 25,000. Cel7: Eastman Chemical "CAP-504-0.2", cellulose acetate propionate, number average molecular weight 15,000.

[0155] (Second component) -Fatty acid derivative (A)- • Add1: Kawaken Fine Chemicals "Amizol ODE", Oleic Acid Diethanolamide • Add2: Kawaken Fine Chemicals "Amizol CME", coconut oil fatty acid monoethanolamide • Add21: Kawaken Fine Chemicals "Amizol SDHE", stearic acid diethanolamide • Add22: Kawaken Fine Chemicals "Amizol PLME-A", Lauric Acid Monoisopropanolamide

[0156] -(meth)acrylic acid-based compounds (C)- • Add3: Sumitomo Seika "AQUPEC HV-501ER", INCI name "Acrylates / C10-30 Alkyl Acrylate Crosspolymer" • Add4: Sekisui Chemical Co., Ltd. "ACP-8C", INCI name "((Acrylates / Ethylhexyl Acrylate) Crosspolymer) Copolymer" • Add5: NOF Corporation "CERACUTE-F", INCI name "(Glyceryl Methacrylate / Stearyl Methacrylate) Copolymer" • Add6: Sekisui Chemical Co., Ltd. "LMX-5C", INCI name "Methyl methacrylate crosspolymer" • Add7: Ashland Japan "UltraThix P-100", INCI name "(Acrylates / Vinylpyrrolidone) Crosspolymer" • Add8: Dow Chemical "ACUDYN 1000 Polymer", INCI name "(Acrylates / Hydroxyalkyl Acrylate) Copolymer" • Add9: Dow Chemical "Antaron Sensory", INCI name "(vinylpyrrolidone / acrylates / lauryl methacrylate) copolymer"

[0157] -others- • Add10: Tokyo Chemical Industry Co., Ltd., Triethyl Citrate • Add11: Higher Alcohol Industry "KAK-DIBA", Diisobutyl Adipate • Add12: Daihachi Chemical "Daifatty101", dibasic acid ester mixture

[0158] -Aromatic compound (B)- • Add13: Cardlight "GX2053", Cardanol • Add31: DIC, 4-octylphenol • Add32: Fujifilm Wako Pure Chemical Industries, 4-dodecylphenol • Add33: Fujifilm Wako Pure Chemical Industries, 4-2,2-dibutyl-octylphenol

[0159] (Compounds that constitute the first coating layer) -Polyamine compounds- • Fir1: Nippon Shokubai "Epomin SP-003", polyethyleneimine, molecular weight 300 • Fir2: Nippon Shokubai "Epomin SP-006", polyethyleneimine, molecular weight 600 • Fir3: Nippon Shokubai "Epomin SP-012", polyethyleneimine, molecular weight 1200 ·Fir4: Nippon Shokubai's "Epomin SP-018", polyethyleneimine, molecular weight 1800 ·Fir5: Nippon Shokubai's "Epomin SP-200", polyethyleneimine, molecular weight 1000 ·Fir6: Nippon Shokubai's "Epomin HM-2000", polyethyleneimine, molecular weight 30000 ·Fir7: Nippon Shokubai's "Epomin P-1000", polyethyleneimine, molecular weight 70000 ·Fir8: Nitto Boehringer Medical's "PAA-01", polyallylamine, molecular weight 1600 ·Fir9: Nitto Boehringer Medical's "PAA-03", polyallylamine, molecular weight 3000 ·Fir10: Nitto Boehringer Medical's "PAA-05", polyallylamine, molecular weight 5000 ·Fir11: Nitto Boehringer Medical's "PAA-08", polyallylamine, molecular weight 8000 ·Fir12: Nitto Boehringer Medical's "PAA-15C", polyallylamine, molecular weight 15000 ·Fir13: Nitto Boehringer Medical's "PAA-25", polyallylamine, molecular weight 25000 ·Fir14: Mitsubishi Chemical's "Gosenol N-300", polyvinyl alcohol ·Fir15: JNC's "Polylysine 10", polylysine ·Fir16: Ichimaru Pharcos's "Polylysine 10", polylysine

[0160] - Polyvinyl alcohol, and polyvinyl pyrrolidone - ·Fir17: Mitsubishi Chemical's "Gosenol N-300", polyvinyl alcohol ·Fir18: Nippon Shokubai's "K-30", polyvinyl pyrrolidone

[0161] - Straight-chain saturated fatty acid - ·Fir19: NOF Corporation's "NAA-222S", behenic acid (22 carbon atoms) ·Fir20: Fujifilm Wako Pure Chemical Corporation, arachidic acid (20 carbon atoms) ·Fir21: FUJIFILM Wako Pure Chemical Industries, Palmitic acid (14 carbon atoms) ·Fir22: FUJIFILM Wako Pure Chemical Industries, Lauric acid (12 carbon atoms) ·Fir23: FUJIFILM Wako Pure Chemical Industries, Lignoceric acid (24 carbon atoms)

[0162] -Hydroxy fatty acid- ·Fir24: Ito Oil Manufacturing "12-Hydroxystearic acid", Hydroxystearic acid ·Fir25: NOF Corporation, Hydrogenated castor oil fatty acid

[0163] -Amino acid-based compound- ·Fir26: Ajinomoto "Amihope LL", Lauroyl lysine

[0164] (Compound constituting the second coating layer) -Wax- ·Sec1: SENKA "CN-100", Carnauba wax ·Sec2: Toagosei "TOWAX-1F3", Carnauba wax ·Sec3: Toagosei "TOWAX-1F6", Carnauba wax ·Sec4: Toagosei "TOWAX-1F8", Carnauba wax ·Sec5: Toagosei "TOWAX-1F12", Carnauba wax ·Sec6: Toagosei "TOWAX-5B2", Carnauba wax ·Sec7: Toagosei "TOWAX-1B4", Carnauba wax ·Sec8: Toagosei "TOWAX-4F2", Candelilla wax ·Sec9: Toagosei "TOWAX-4F3", Candelilla wax ·Sec10: Toagosei "TOWAX-4F4", Candelilla wax ·Sec11: Toagosei "TOWAX-6B2", Damask rose flower wax ·Sec12: Toagosei "TOWAX-6F2", Sunflower seed wax ·Sec13: Ogura Chemical Industry Co., Ltd., Rice wax Sec14: Boso Oils "SS-1", rice wax • Sec15: Nisshin Oillio "Cosmoll 222", Diisostearyl Malate

[0165] -Polyvalent metal salts- Sec21: Fujifilm Wako Pure Chemical Industries, Aluminum Sulfate Sec22: Fujifilm Wako Pure Chemical Industries, Polyaluminum Chloride Sec23: Fujifilm Wako Pure Chemical Industries, Iron Chloride Sec24: Fujifilm Wako Pure Chemical Industries, Calcium Hydroxide

[0166] (External additive) -Silicon-containing compound particles- • Sur1: Aerosil Japan "AEROSIL R972", dimethylsilylated silica particles, volume average particle size = 16 nm • Sur2: Japan Aerosil "AEROSIL RY200S", dimethicone silica particles, volume average particle size = 12nm

[0167] -Metal soap particles- • Sur3: NOF Corporation "MZ-2", zinc stearate particles, volume-average particle size = 1.5 μm • Sur4: NOF "Magnesium Stearate S", magnesium stearate particles, volume-average particle size = 1 μm

[0168] - Fatty acid ester particles - • Sur6: Kao "Excepearl SS", stearyl stearate particles, volume-average particle size = 1 μm -Metal oxide particles- • Sur7: Sakai Chemical "FINEX-50", zinc oxide particles, volume-average particle size = 1.5 μm The volume-average particle size of the external additive was measured using the same procedure as that used for the volume-average particle size of the cellulose particles.

[0169] <Example 1> (Particle precursor production process) 800 parts of Cel1 as cellulose acetate and 200 parts of Add1 as the second component were kneaded using a twin-screw kneading apparatus (manufactured by Toshiba Machine Co., Ltd., TEX41SS) with the cylinder temperature adjusted to 220°C to produce resin in pellet form (hereinafter referred to as resin pellets). 130 parts of the resin pellets are completely dissolved in 870 parts of ethyl acetate. This is added to an aqueous liquid containing 50 parts of calcium carbonate and 500 parts of pure water and stirred for 3 hours (hereinafter referred to as "the first stirring time"). To this, a solution obtained by dispersing 4 parts of carboxymethyl cellulose (hereinafter also referred to as "CMC") and 200 parts of methyl ethyl ketone in 600 parts of pure water is added, and the mixture is stirred with a high-speed emulsifier for 5 minutes. To this, 10 parts of sodium hydroxide is added, and the mixture is heated to 80°C and stirred for 3 hours to remove ethyl acetate and methyl ethyl ketone. Hydrochloric acid of the same amount as sodium hydroxide is added thereto, and after filtering the residue, it is dispersed again in pure water to obtain a particle precursor dispersion (solid content concentration: 10%).

[0170] (Saponification step) 17.5 parts of a 20% aqueous sodium hydroxide solution is added to 500 parts of the particle precursor dispersion, and the mixture is stirred at a saponification temperature of 30°C for 6 hours. Hydrochloric acid is added to the saponified slurry to adjust the pH to 7, and then filtration and washing are repeated until the conductivity of the filtrate becomes 10 μs / cm or less to obtain cellulose particles.

[0171] (Examples 2 to 20, Comparative Examples 1 to 3) (Particle precursor production step) A particle precursor dispersion (solid content concentration: 10%) was obtained by the same procedure as in Example 1 (particle precursor production step) except that the type of cellulose acetate, the amount of cellulose acetate added, the type of the second component, the amount of the second component added, and the cylinder temperature were as shown in Table 1 during the production of the resin pellets.

[0172] (Saponification step) Cellulose particles were obtained by the same procedure as in the (saponification step) of Example 1.

[0173] (Example 21) (Particle precursor production step) A particle precursor dispersion (solid content concentration 10%) was obtained using the same procedure as in Example 1 (particle precursor manufacturing process).

[0174] (saponification process) Cellulose particles were obtained using the same procedure as in Example 1 (saponification step).

[0175] (Coating layer formation process) A mother particle dispersion was obtained by mixing 1,000 parts of cellulose particles, which are the mother particles, with 10,000 parts of deionized water. Five parts of Fir16 were added to the mother particle dispersion as a compound constituting the first coating layer, and the mixture was stirred for 1 hour to form a coating layer. The cellulose particles with the coating layer were filtered and washed repeatedly until the conductivity of the filtrate was 10 μs / cm or less, thereby obtaining cellulose particles with a coating layer.

[0176] <Examples 22-38> In the (coating layer formation process), cellulose particles having a coating layer were obtained using the same procedure as in Example 21, except that the type of compound constituting the first coating layer ("first layer compound" in Table 1) was as shown in Table 1.

[0177] <Example 39> (Particle precursor production process) A particle precursor dispersion (solid content concentration 10%) was obtained using the same procedure as in Example 1 (particle precursor manufacturing process).

[0178] (saponification process) Cellulose particles were obtained using the same procedure as in Example 1 (saponification step).

[0179] (Coating layer formation process) A mother particle dispersion was obtained by mixing 1,000 parts of cellulose particles, which are the mother particles, with 10,000 parts of deionized water. Five parts of Fir16 were added to the mother particle dispersion as a compound constituting the first coating layer, and the mixture was stirred for one hour to form the first coating layer, thus obtaining a cellulose particle dispersion having the first coating layer. Next, 4 parts of Sec1 as wax and 50 parts of pure water were stirred in a high-speed emulsifier to prepare a second coating layer forming emulsion. The entirety of the second coating layer forming emulsion was added to the cellulose particle dispersion having the first coating layer, and the mixture was stirred for 24 hours to form the second coating layer, thereby obtaining a cellulose particle dispersion having both the first and second coating layers. Cellulose particles having a first and second coating layer were repeatedly filtered and washed until the conductivity of the filtrate was 10 μs / cm or less, thereby obtaining cellulose particles having a first and second coating layer.

[0180] <Examples 40-56> In the (coating layer formation process), cellulose particles having the first and second coating layers were obtained using the same procedure as in Example 39, except that the amount of compound constituting the first coating layer, the type of wax, and the amount of wax added were as shown in Table 1.

[0181] <Example 57> (Particle precursor manufacturing process), (Saponification process), and (Coating layer formation process) Cellulose particles having first and second coating layers were obtained using the same procedure as in Example 39.

[0182] (External addition process) To 30 parts of cellulose particles having a first and second coating layer, 0.6 parts of Sur1 was added as an external additive, and the mixture was combined in a mixing mill (Wonder Crusher, manufactured by Osaka Chemical Co., Ltd.) to obtain cellulose particles containing the external additive.

[0183] <Examples 58-64> In the (external additive step), cellulose particles containing the external additive were obtained using the same procedure as in Example 57, except that the type and amount of the external additive were as shown in Table 1.

[0184] <Examples 65-72> Cellulose particles having first and second coating layers were obtained using the same procedure as in Example 39, except that the amount of calcium carbonate added, the first stirring time, and the amount of sodium hydroxide added in the particle precursor manufacturing process were as shown in Table 1.

[0185] <Example 73> Cellulose particles having a coating layer were obtained using the same procedure as in Example 39, except that the step of adding 5 parts of Fir16 as a compound constituting the first coating layer to the mother particle dispersion and stirring for 1 hour was omitted in the (coating layer formation step).

[0186] <Comparative Example 4> (Particle precursor production process) 130 parts of Cel1 as cellulose acylate were completely dissolved in 870 parts of ethyl acetate. This was added to an aqueous solution containing 55 parts of calcium carbonate and 500 parts of pure water, and stirred for 2 hours. A solution of 5 parts of carboxymethylcellulose and 200 parts of methyl ethyl ketone dispersed in 600 parts of pure water was added, and the mixture was stirred for 5 minutes using a high-speed emulsifier. 10 parts of sodium hydroxide were added, and the mixture was heated to 80°C and stirred for 3 hours to remove ethyl acetate and methyl ethyl ketone. An equal amount of dilute hydrochloric acid was added to the mixture, the residue was filtered, and then dispersed again in pure water to obtain a particle precursor dispersion (solid content concentration 10%).

[0187] (saponification process) Cellulose particles were obtained using the same procedure as in Example 1 (saponification step).

[0188] <Comparative Example 5> (Particle precursor manufacturing process) and (Saponification process) Cellulose particles were obtained using the same procedure as in Comparative Example 4.

[0189] (Coating layer formation process) Cellulose particles having a coating layer were obtained using the same procedure as in Example 21 (coating layer formation step), except that the cellulose particles obtained by the above procedure were used as mother particles, and the amount of compound constituting the first coating layer added per 100 parts of mother particles was changed as shown in Table 1.

[0190] <Comparative Example 6> (Particle precursor manufacturing process) and (Saponification process) Cellulose particles were obtained using the same procedure as in Comparative Example 4.

[0191] (Coating layer formation process) Cellulose particles having the first and second coating layers were obtained using the same procedure as in Example 39 (coating layer formation step), except that the cellulose particles obtained by the above procedure were used as mother particles, and the amount of compound constituting the first coating layer added per 100 parts of mother particles was changed as shown in Table 1.

[0192] <Comparative Example 7> (Particle precursor manufacturing process), (Saponification process), and (Coating layer formation process) Cellulose particles having first and second coating layers were obtained using the same procedure as in Comparative Example 6.

[0193] Cellulose particles having an external additive were obtained using the same procedure as in Example 57 (external additive step), except that cellulose particles having the first and second coating layers obtained by the above procedure were used.

[0194] <Examples 74-77> (Particle precursor manufacturing process), (Saponification process), and (Coating layer formation process) Cellulose particles having the first and second coating layers were obtained using the same procedure as in Example 39, except that the type of wax was changed as shown in Table 1 during the coating layer formation process, and the polyvalent metal salts listed in Table 1 were added in the amounts shown in Table 1 along with the wax and pure water when preparing the second coating layer forming emulsion.

[0195] (External addition process) Cellulose particles having an external additive were obtained using the same procedure as in Example 57, except that cellulose particles having the first and second coating layers obtained by the above procedure were used.

[0196] <Comparative Examples 8-12> The following particles were used as cellulose particles in each example. Comparative Example 8: CELLULOBEADS D10 (manufactured by Daito Kasei Co., Ltd.) Comparative Example 9: OTS-0.5A CELLULOBEADS D10 (manufactured by Daito Chemical Co., Ltd.) Comparative example 10: S-STM CELLULOBEADS D-5 (manufactured by Daito Kasei Co., Ltd.) Comparative Example 11: Self-flow C25 (manufactured by JNC Corporation) Comparative Example 12: Self-flow TA25 (manufactured by JNC Corporation)

[0197] <Comparative Examples 13-16> Cellulose particles were obtained for each example following the procedure below. Comparative Example 13: Cellulose particles were obtained according to the procedure described in Example 1 of Japanese Patent Publication No. 6872068. Comparative Example 14: Cellulose particles were obtained according to the procedure described in Example 2 of Japanese Patent Publication No. 6872068. Comparative Example 15: Cellulose particles were obtained according to the procedure described in Example 1 of Japanese Patent Publication No. 2021-021044. Comparative Example 16: Cellulose particles were obtained according to the procedure described in Example 1 of Japanese Patent Publication No. 2021-021045.

[0198] <Examples 78-82> Cellulose particles were obtained using the same procedure as in Example 1, except that the type of the second component was changed as shown in Table 1 during the particle precursor manufacturing process.

[0199] <Examples 83-92> Cellulose particles having a coating layer were obtained using the same procedure as in Example 21, except that the type of compound constituting the first coating layer and the amount of compound added to the first coating layer were changed as shown in Table 1 during the (coating layer formation process).

[0200] <Example 93> In the (coating layer formation process), cellulose particles having first and second coating layers were obtained using the same procedure as in Example 39, except that the type of compound constituting the first coating layer (referred to as "first layer compound" in Table 1) and the amount of compound added to the first coating layer were as shown in Table 1.

[0201] <Example 94> Cellulose particles having the first and second coating layers were obtained using the same procedure as in Example 93, except that when preparing the second coating layer forming emulsion in the (coating layer formation process), the polyvalent metal salts listed in Table 1 were added together with wax and pure water in the amounts listed in Table 1.

[0202] <Example 95> (Particle precursor manufacturing process), (Saponification process), and (Coating layer formation process) Cellulose particles having first and second coating layers were obtained using the same procedure as in Example 94.

[0203] (External addition process) To 30 parts of cellulose particles having a first and second coating layer, 0.6 parts of Sur1 was added as an external additive, and the mixture was combined in a mixing mill (Wonder Crusher, manufactured by Osaka Chemical Co., Ltd.) to obtain cellulose particles containing the external additive.

[0204] <Rating> The cellulose particles obtained in each example were used to evaluate their biodegradability and flexibility.

[0205] (Biodegradability assessment) The biodegradation rate after 60 days was measured and calculated in accordance with JIS K6950:2000 (ISO 14851:1999).

[0206] (Flexibility assessment) The Young's modulus was calculated using a microcompression tester (MCT-510, Shimadzu Corporation). Specifically, cellulose particles were scattered on the sample stage, and the initial position was adjusted so that a single particle was contained within the indenter tip while observing with an optical microscope. Compression was performed at a sample stage movement speed of 0.2 μm / s, and the test force corresponding to the displacement was continuously detected. The measurement was terminated when the particles were completely crushed. The obtained stress-strain curve was represented by two straight lines with different slopes. The intersection of these two lines was defined as the yield point (εy, σy), and the slope of the line from the origin was defined as the apparent Young's modulus Ey, as shown in the following formula. Table 2 shows the values ​​obtained from the following formula. (Equation) Ey = σy / εy

[0207] [Table 1-1]

[0208] [Table 1-2]

[0209] [Table 1-3]

[0210] [Table 1-4]

[0211] [Table 2-1]

[0212] [Table 2-2]

[0213] [Table 2-3]

[0214] [Table 2-4]

[0215] The content of the first and second components in Table 2 were calculated as follows. Ten g of cellulose particles without a coating layer or external additives were placed in 500 g of tetrahydrofuran and stirred at 50°C for 4 hours. The mixture was then filtered to recover the cellulose particles. The recovered cellulose particles were dried at 40°C for 8 hours, and the mass Wp (g) was measured. The content of the first component (in parts) was determined using (Equation 1-1), and the content of the second component (in parts) was determined using (Equation 1-2). (Formula 1-1) First component content = (Wp / 10)×100 (Formula 1-2) Second component content = ((10-Wp) / 10)×100

[0216] From the above results, it can be seen that the cellulose particles of this embodiment have excellent biodegradability and flexibility.

Claims

1. The first component is cellulose, The second component is selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C), The fatty acid derivative (A) is a fatty acid derivative having a saturated aliphatic group with 10 to 25 carbon atoms. Cellulose particles having a saturated aliphatic group with 10 to 25 carbon atoms, wherein the octanol / water partition coefficient of the fatty acid derivative is 5 to 10.

2. A first component which is cellulose, The second component is selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C), Cellulose particles wherein the fatty acid derivative (A) is a fatty acid ethanolamide.

3. A first component which is cellulose, The second component is selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C), The aromatic compound (B) is an aromatic compound (B0) having an aliphatic group having 8 to 20 carbon atoms, a phenolic hydroxyl group, and at least one of a monoglycidyl ether group directly bonded to the aromatic group. Cellulose particles having an octanol / water partition coefficient of aromatic compound (B0) between 5 and 20.

4. A first component which is cellulose, The second component is selected from the group consisting of a fatty acid derivative (A), an aromatic compound (B) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group along with a long-chain aliphatic group, and a (meth)acrylic acid compound (C), A mother particle containing the first component and the second component, A coating layer that covers the aforementioned mother particles, comprising at least one selected from the group consisting of polyamine compounds, waxes, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds, It has, The coating layer comprises a first coating layer that covers the mother particles and contains the polyamine compound, and a second coating layer that covers the first coating layer and contains the wax. The second coating layer further contains cellulose particles containing a polyvalent metal salt.

5. Cellulose particles according to any one of claims 1 to 4, wherein the content of the first component is 70% by mass or more and 95% by mass or less of the total content of the first component and the second component.

6. Cellulose particles according to any one of claims 1 to 5, wherein the total content of the second component is 5% by mass or more and 30% by mass or less, relative to the total content of the first component and the second component.

7. The cellulose particles according to any one of claims 2 to 4, wherein the fatty acid derivative (A) is a fatty acid derivative having a saturated aliphatic group having 10 to 25 carbon atoms.

8. The cellulose particles according to claim 7, wherein the octanol / water partition coefficient of the fatty acid derivative having a saturated aliphatic group having 10 to 25 carbon atoms is 5 to 10.

9. The cellulose particles according to claim 1, claim 3, or claim 4, wherein the fatty acid derivative (A) is a fatty acid ethanolamide.

10. The cellulose particle according to claim 1, claim 2, or claim 4, wherein the aromatic compound (B) is an aromatic compound (B0) having at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to the aromatic group, together with an aliphatic group having 8 to 20 carbon atoms.

11. The cellulose particles according to claim 10, wherein the octanol / water partition coefficient of the aromatic compound (B0) is 5 or more and 20 or less.

12. A mother particle containing the first component and the second component, A coating layer that covers the aforementioned mother particles, comprising at least one selected from the group consisting of polyamine compounds, waxes, linear saturated fatty acids, hydroxy fatty acids, and amino acid compounds, Cellulose particles according to any one of claims 1 to 3, having the characteristics of the claims.

13. The cellulose particle according to claim 12, wherein the polyamine compound is at least one selected from the group consisting of polyethyleneimine and polylysine.

14. The cellulose particles according to claim 12 or claim 13, wherein the wax is carnauba wax.

15. The cellulose particle according to any one of claims 12 to 14, wherein the coating layer comprises a first coating layer that coats the mother particle and contains the polyamine compound, and a second coating layer that coats the first coating layer and contains the wax.

16. The cellulose particles according to claim 15, further comprising a polyvalent metal salt in the second coating layer.

17. Cellulose particles according to any one of claims 1 to 16, wherein at least one external additive selected from the group consisting of silicon-containing compound particles and metal soap particles is added externally.

18. The cellulose particles according to claim 17, wherein the silicon-containing compound particles are silica particles.

19. Cellulose particles according to any one of claims 1 to 18, wherein the volume-average particle diameter is 3 μm or more and less than 10 μm.

20. Cellulose particles according to any one of claims 1 to 19, wherein the large diameter side particle size distribution index GSDv is 1.0 or more and 1.7 or less.

21. Cellulose particles according to any one of claims 1 to 20, wherein the sphericity is 0.90 or higher.

22. The cellulose particles according to any one of claims 1 to 21, wherein the number-average molecular weight of the cellulose is 37,000 or more.

23. The cellulose particles according to claim 22, wherein the number-average molecular weight of the cellulose is 45,000 or more.

24. Cellulose particles according to any one of claims 1 to 23, wherein the surface smoothness is 80% or more.

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