JP7622362B2 - Resin particles - Google Patents

Description

The present invention relates to resin particles.

Patent Document 1 proposes a resin composition that includes "a cellulose acylate (A) having a group having a hydrocarbon chain with 5 or more carbon atoms at its side chain, a polyester resin (B), and an ester compound (C) having a molecular weight of 250 to 2000, in which the mass ratio ((B)/(A)) of the polyester resin (B) to the cellulose acylate (A) is 0.05 to 0.5, and the mass ratio ((C)/(A)) of the ester compound (C) to the cellulose acylate (A) is 0.02 to 0.15."

Patent Document 2 proposes a cellulose-based resin in which "a cardanol analog or a derivative thereof, which contains cardanol and cardol and has a cardol content of 3.0% by mass or more, is bonded to the cellulose or derivative thereof by utilizing the cellulose hydroxyl groups of the cellulose or derivative thereof and the phenolic hydroxyl groups of the cardanol analog."

JP 2019-151794 A JP 2015-081326 A

The object of the present invention is to provide a resin particle containing cellulose acylate (A), an aromatic compound (B) that does not have a functional group that reacts with the cellulose acylate (A) and has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to the aromatic group, and an ester compound (C) that has a long-chain hydrocarbon group, the mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is less than 0.15 or exceeds 0.8, the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is less than 0.02 or exceeds 0.10, the mass loss rate after 90 days in water at 50°C and pH 7.8 exceeds 30%, or the hydrophobicity degree is less than 30, and the resin particle has excellent resistance to hydrolysis in water while having biodegradability.

The above-mentioned problems can be solved by the following means: <1> A cellulose acylate (A),
an aromatic compound (B) which does not have a functional group reactive with the cellulose acylate (A) and has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
and (C) an ester compound having a long chain hydrocarbon group,
a mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is 0.15 or more and 0.8 or less;
The resin particles have a mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) of 0.02 or more and 0.10 or less.
<2> The resin particles according to <1>, wherein the cellulose acylate (A) has two or more kinds of acyl groups.
<3> The resin particles according to <1> or <2>, wherein the aromatic compound (B) is a cardanol compound (B1).
<4> The resin particles according to <3>, wherein the cardanol compound (B1) is at least one compound selected from the group consisting of a compound represented by the following general formula (CDN1) and a compound represented by the following general formula (CDN1-e):

(In general formula (CDN1), R ¹ represents an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. R ² represents a hydroxy group, a carboxy group, an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. P 2 represents an integer of 0 to 4. When P 2 is 2 or more, a plurality of R ^2s may be the same group or different groups.)

(In general formula (CDN1-e), L _EP represents a single bond or a divalent linking group. In general formula (CDN1-e), R ¹ , R ² and P2 have the same meanings as R ¹ , R ² and P2 in general formula (CDN1), respectively.)
<5> The resin particles according to any one of <1> to <4>, wherein the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups.
<6> The resin particles according to <5>, wherein the two or more long-chain hydrocarbon groups of the ester compound (C) are hydrocarbon groups having 8 to 20 carbon atoms.
<7> The resin particles according to <6>, wherein at least one of the two or more hydrocarbon groups having 8 to 20 carbon atoms contained in the ester compound (C) is a stearyl group.
<8> The resin particles according to any one of <1> to <7>, wherein a mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is 0.20 or more and 0.40 or less.
<9> The resin particles according to any one of <1> to <8>, wherein a mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is 0.03 or more and 0.07 or less.
<10> Cellulose acylate (A),
an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
and an ester compound (C) having a long chain hydrocarbon group,
Resin particles having a mass loss rate of 30% or less after 90 days in water at 50°C and pH 7.8.
<11> Cellulose acylate (A),
an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
and an ester compound (C) having a long chain hydrocarbon group,
Resin particles having a hydrophobicity of 30 or more as measured by the following method.
(Method of measuring hydrophobicity)
50 g of distilled water is placed in a 300 ml beaker and stirred with a stirrer. 0.2 g of resin particles are placed in the beaker and dispersed in the distilled water. Methanol is dripped into the beaker with a dropper. The amount of methanol dripped when all the resin particles have settled is defined as Me (g), and the hydrophobicity is calculated by the following formula.
Hydrophobicity=Me/(Me+50)
<12> The resin particles according to any one of <1> to <11>, having a volume average particle size of 3 μm or more and 100 μm or less.
<13> The resin particles according to any one of <1> to <12>, wherein a large diameter particle size distribution index GSDv is 1.50 or less.

According to the invention related to <1>, in resin particles containing cellulose acylate (A), an aromatic compound (B) that does not have a functional group that reacts with the cellulose acylate (A) and has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to the aromatic group, and an ester compound (C) that has a long-chain hydrocarbon group, the resin particles are biodegradable and have excellent resistance to hydrolysis in water compared to when the mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is less than 0.15 or exceeds 0.8, or the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is less than 0.02 or exceeds 0.10.

According to the invention related to <2>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to when the cellulose acylate (A) has one type of acyl group.

According to the invention related to <3> or <4>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to when the aromatic compound (B) is bisphenol A.

According to the invention of item <5>, <6> or <7>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to when the ester compound (C) is cetyl 2-ethylhexanoate.

According to the invention related to <8>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to when the mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is less than 0.20 or exceeds 0.40.

According to the invention related to <9>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, as compared with a case in which the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is less than 0.03 or exceeds 0.07.

According to the invention related to <10>, in resin particles containing cellulose acylate (A), an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group, and an ester compound (C) having a long-chain hydrocarbon group, the resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, as compared with resin particles in which the mass loss rate after 90 days in water at 50°C and pH 7.8 exceeds 30%.

According to the invention related to <11>, in resin particles containing cellulose acylate (A), an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group, and an ester compound (C) having a long-chain hydrocarbon group, the resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to resin particles having a hydrophobicity degree of less than 30.

According to the invention related to <12>, resin particles are provided which are biodegradable and have excellent resistance to hydrolysis in water, compared to resin particles having a volume average particle size of less than 3 μm or more than 100 μm.

According to the invention related to <13>, resin particles are provided that are biodegradable and have excellent resistance to hydrolysis in water, compared to those in which the large diameter particle size distribution index GSDv exceeds 1.50.

Hereinafter, an embodiment of the present invention will be described as an example. The description and examples are merely illustrative of the embodiment, and are not intended to limit the scope of the present invention.
In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.
Each component may contain multiple types of the corresponding substance.
When referring to the amount of each component in a composition, if the composition contains multiple substances corresponding to each component, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

In this specification, the cellulose acylate (A), the aromatic compound (B), and the ester compound (C) are also referred to as component (A), component (B), and component (C), respectively.

<Resin Particles>
First Embodiment
The resin particles according to the first embodiment contain a cellulose acylate (A), an aromatic compound (B) which does not have a functional group that reacts with the cellulose acylate (A) and which has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group, and an ester compound (C) which has a long-chain hydrocarbon group.
The mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is 0.15 or more and 0.8 or less, and the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is 0.02 or more and 0.10 or less.

The resin particles according to the first embodiment have the above-mentioned configuration, and are biodegradable while also having excellent resistance to hydrolysis in water. The reason for this is presumed to be as follows.

Cellulose is known as a resin that is rapidly biodegradable, but due to its poor moldability, it has been difficult to produce resin particles containing cellulose.
In order to impart moldability to cellulose, it is common to use cellulose acylate (A) in which some of the hydroxyl groups of cellulose are substituted with acyl groups, and to add a plasticizer. However, the cellulose acylate (A) has a problem that its biodegradability is slower than that of cellulose.

The resin particles according to the first embodiment contain cellulose acylate (A) (i.e., component (A)) and aromatic compound (B) (i.e., component (B)) which does not have a functional group that reacts with the cellulose acylate (A) and has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group. This enhances the biodegradability of the resin particles according to the first embodiment.
The long-chain aliphatic group of component (B) has a low affinity with component (A), and therefore has a repulsive force between component (A). On the other hand, the phenolic hydroxyl group and the monoglycidyl ether group directly bonded to the aromatic group have a high affinity with component (A). In this way, since component (B) has a site with low affinity and a site with low affinity between component (A) and component (A), it is considered that component (A) and component (B) are mixed in a nearly uniform state. For this reason, the resin particles according to the first embodiment are easily caused to thermally decompose component (A) by the phenolic hydroxyl group or glycidyl ether group of component (B), and biodegradability is enhanced. This effect is exhibited when the mass ratio ((B)/(A)) of component (A) to component (B) is in the range of 0.15 to 0.8.

However, resin particles containing components (A) and (B) may undergo hydrolysis in water at temperatures of 40°C or higher, which may accelerate biodegradability. Therefore, resin particles containing components (A) and (B) may have poor durability in water.

The resin particles according to the first embodiment contain a component (A), a component (B), and an ester compound (C) having a long-chain hydrocarbon group (i.e., component (C)). This allows the resin particles according to the first embodiment to have excellent resistance to hydrolysis in water while ensuring biodegradability.
The ester group of component (C) interacts with the acyl group of component (A) to increase the affinity with (A). On the other hand, the long-chain hydrocarbon group of component (C) has a low affinity with component (A) and is easily oriented on the surface of the resin particle. In other words, the resin particle according to the first embodiment has a hydrophobic particle surface. Therefore, water is less likely to penetrate into the resin particle, and the resistance to hydrolysis in water is improved.
In addition, the ester group of component (C) also has an affinity with the phenolic hydroxyl group or monoglycidyl ether group of component (B) and suppresses the thermal decomposition of component (A) caused by the phenolic hydroxyl group or the monoglycidyl ether group, which is also a factor in improving the resistance to hydrolysis in water.
This effect is enhanced when the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is 0.02 or more and 0.10 or less.

Therefore, the resin particles according to the first embodiment are biodegradable and have excellent resistance to hydrolysis in water.

Second Embodiment
The resin particles according to the second embodiment contain a component (A), a component (B), and a component (C).
In addition, the mass loss rate after 90 days in water at 50° C. and pH 7.8 is 30% or less.

The resin particles according to the second embodiment, due to the above-mentioned configuration, are biodegradable and have excellent resistance to hydrolysis in water. The reason for this is presumed to be as follows.

As described above, the resin particles contain the component (A) and the component (B), and thus become biodegradable resin particles.
In addition, the resin particles further contain component (C), which improves the resistance to hydrolysis in water. Furthermore, the resin particles according to the second embodiment have a mass loss rate of 30% or less after 90 days in water at 50° C. and pH 7.8. This indicates that the resin particles have high resistance to hydrolysis in water.
For example, by making the mass ratio of component (A) to component (B) ((B)/(A)) 0.15 or more and 0.8 or less, and the mass ratio of component (A) to component (C) ((C)/(A)) 0.02 or more and 0.10 or less, resin particles are likely to have a mass loss rate of 30% or less after 90 days in water at 50°C and pH 7.8.

Therefore, the resin particles according to the second embodiment are biodegradable and have excellent resistance to hydrolysis in water.

Third Embodiment
The resin particles according to the third embodiment contain a component (A), a component (B), and a component (C).
In addition, the hydrophobicity measured by the following method is 30 or more.
(Method of measuring hydrophobicity)
50 g of distilled water is placed in a 300 ml beaker and stirred with a stirrer. 0.2 g of resin particles are placed in the beaker and dispersed in the distilled water. Methanol is dripped into the beaker with a dropper. The amount of methanol dripped when all the resin particles have settled is defined as Me (g), and the hydrophobicity is calculated by the following formula.
Hydrophobicity=Me/(Me+50)

The resin particles according to the third embodiment, due to the above-mentioned configuration, are biodegradable and have excellent resistance to hydrolysis in water. The reason for this is presumed to be as follows.

As described above, the resin particles contain the component (A) and the component (B), and thus become biodegradable resin particles.
In addition, the resin particles further contain component (C), and the hydrophobicity of the resin particle surface is increased by the above-mentioned mechanism. Furthermore, the resin particles according to the third embodiment have a hydrophobicity of 30 or more as measured by the above-mentioned method. This indicates that the surface of the resin particles has high hydrophobicity. Therefore, water is less likely to penetrate into the resin particles, and the resistance to hydrolysis in water is improved.
For example, by making the mass ratio of component (A) to component (B) ((B)/(A)) 0.15 or more and 0.8 or less, and the mass ratio of component (A) to component (C) ((C)/(A)) 0.02 or more and 0.10 or less, resin particles are likely to have a hydrophobicity of 30 or more as measured by the above-mentioned method.

Therefore, the resin particles according to the third embodiment are biodegradable and have excellent resistance to hydrolysis in water.

Hereinafter, the resin particles corresponding to the resin particles according to the first, second, and third embodiments (hereinafter also referred to as "resin particles according to this embodiment") will be described in detail. However, an example of the resin particles of the present invention may be any of the resin particles according to the first, second, and third embodiments.

The resin particles according to this embodiment are described in detail below.

(Cellulose Acylate (A): Component (A))
Cellulose acylate (A) is a cellulose derivative in which at least a part of the hydroxyl groups in cellulose is substituted with an acyl group (acylation). The acyl group is a group having the structure -CO-R ^AC (R ^AC represents a hydrogen atom or a hydrocarbon group).

Cellulose acylate (A) is, for example, a cellulose derivative represented by the following general formula (CA):

In the general formula (CA), A ¹ , A ² and A ³ each independently represent a hydrogen atom or an acyl group, and n represents an integer of 2 or more. However, at least a part of n A ¹ s, n A ² s and n A ^{3 s} represent an acyl group. The n A ¹ s in a molecule may all be the same, some may be the same or different from each other. Similarly, the n A ² s and n A ³ s in a molecule may all be the same, some may be the same or different from each other.

The acyl group represented by A ¹ , A ² and A ³ may have a hydrocarbon group that is linear, branched or cyclic, but is preferably linear or branched, and more preferably linear.

The hydrocarbon group in the acyl group represented by A ¹ , A ² and A ³ may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, but is more preferably a saturated hydrocarbon group.

The acyl groups represented by ^A1 , ^A2 and ^A3 are preferably acyl groups having a carbon number of 1 to 6. That is, the cellulose acylate (A) is preferably a cellulose acylate (A) having an acyl group having a carbon number of 1 to 6. The cellulose acylate (A) having an acyl group having a carbon number of 1 to 6 is more likely to give resin particles having excellent impact resistance than the cellulose acylate (A) having an acyl group having a carbon number of 7 or more.

The acyl group represented by A ¹ , A ² and A ³ may be a group in which a hydrogen atom in the acyl group is substituted with a halogen atom (e.g., a fluorine atom, a bromine atom, an iodine atom), an oxygen atom, a nitrogen atom or the like, but is preferably unsubstituted.

Examples of the acyl group represented by A ¹ , A ² and A ³ include a formyl group, an acetyl group, a propionyl group, a butyryl group (butanoyl group), a propenoyl group, a hexanoyl group, etc. Among these, the acyl group is preferably an acyl group having 2 to 4 carbon atoms from the viewpoint of improving the biodegradability and hydrolysis resistance in water of the resin particles.

The acyl groups represented by A ¹ , A ² and A ³ preferably contain two or more kinds of acyl groups, from the viewpoint of improving the biodegradability and resistance to hydrolysis in water of the resin particles.

Examples of cellulose acylates (A) include cellulose acetate (cellulose monoacetate, cellulose diacetate (DAC), cellulose triacetate), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), etc.

As the cellulose acylate (A), from the viewpoint of improving the biodegradability of the resin particles and resistance to hydrolysis in water, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) are preferred, with cellulose acetate propionate (CAP) being more preferred.

The cellulose acylate (A) may be used alone or in combination of two or more.

The weight average degree of polymerization of cellulose acylate (A) is preferably 200 to 1,000, more preferably 500 to 1,000, and even more preferably 600 to 1,000, from the viewpoint of excellent moldability, impact resistance, or toughness of the resin particles.

The weight-average degree of polymerization of the cellulose acylate (A) is determined from the weight-average molecular weight (Mw) by the following procedure.
First, the weight average molecular weight (Mw) of the cellulose acylate (A) is measured in terms of polystyrene using tetrahydrofuran with a gel permeation chromatography apparatus (GPC apparatus: Tosoh Corporation, HLC-8320GPC, column: TSKgel α-M).
Next, the degree of polymerization of cellulose acylate (A) is calculated by dividing the molecular weight of the constituent unit of cellulose acylate (A). For example, when the substituent of cellulose acylate is an acetyl group, the molecular weight of the constituent unit is 263 when the degree of substitution is 2.4, and 284 when the degree of substitution is 2.9.

From the viewpoint of improving the biodegradability and hydrolysis resistance in water of the resin particles, the substitution degree of cellulose acylate (A) is preferably 1.5 or more and 2.9 or less, more preferably 1.6 or more and 2.8 or less, even more preferably 1.7 or more and 2.7 or less, and particularly preferably 1.8 or more and 2.7 or less.

In cellulose acetate propionate (CAP), the ratio of the degree of substitution of acetyl groups to propionyl groups (acetyl groups/propionyl groups) is preferably 0.01 or more and 1 or less, more preferably 0.05 or more and 0.1 or less, from the viewpoint of improving the biodegradability and resistance to hydrolysis in water of the resin particles.

In cellulose acetate butyrate (CAB), the ratio of the degree of substitution of acetyl groups to butyryl groups (acetyl groups/butyryl groups) is preferably 0.05 or more and 3.5 or less, more preferably 0.08 or more and 3.0 or less, from the viewpoint of improving the biodegradability of the resin particles and resistance to hydrolysis in water.

The degree of substitution of cellulose acylate (A) is an index showing the degree to which hydroxyl groups of cellulose are substituted with acyl groups. In other words, the degree of substitution is an index showing the degree of acylation of cellulose acylate (A). Specifically, the degree of substitution means the intramolecular average number of substitutions in which three hydroxyl groups in a D-glucopyranose unit of cellulose acylate are substituted with acyl groups. The degree of substitution is determined from the integral ratio of the peaks of cellulose-derived hydrogen and acyl group-derived hydrogen in ^1H -NMR (JMN-ECA/manufactured by JEOL RESONANCE).

(Aromatic compound (B): component (B))
The aromatic compound (B) does not have a functional group that reacts with the cellulose acylate (A), and contains, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group. It is an aromatic compound having the formula:
That is, the aromatic compound (B) does not have a functional group that reacts with the cellulose acylate (A), has a long-chain aliphatic group, and has at least one of a phenolic hydroxyl group and a monoglycidyl ether group. It is a compound.
Here, examples of the long-chain aliphatic group include saturated aliphatic groups (alkyl groups) and unsaturated aliphatic groups (alkenyl groups, alkynyl groups) having 6 to 30 carbon atoms (preferably 10 to 20 carbon atoms). The aliphatic group may be linear, branched or cyclic, with linear or branched being preferred, and linear being more preferred.

Examples of aromatic compounds (B) include compounds in which a phenolic hydroxyl group is substituted on a monocyclic ring, a condensed ring (a polycyclic ring having two or more aromatic rings), a polynuclear ring (a polycyclic ring in which aromatic rings are bonded together by carbon-carbon bonds), or a heterocyclic ring (a monocyclic heterocyclic ring, a condensed ring containing a heterocyclic ring, a polynuclear ring containing a heterocyclic ring, etc.) together with a long-chain aliphatic group.

Specific examples of the aromatic compound (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.
Among these, from the viewpoint of improving biodegradability, the cardanol compound (B1) is preferred as the aromatic compound (B).

The cardanol compound (B1) refers to a component contained in a naturally derived compound made from cashew (for example, the compounds represented by the following structural formulas (b-1) to (b-4)) or a derivative of the above component.

The cardanol compound (B1) may be a mixture of naturally occurring compounds derived from cashews (hereinafter also referred to as a "cashew-derived mixture").

The cardanol compound (B1) may be a derivative from a cashew-derived mixture. Examples of derivatives from cashew-derived mixtures include the following mixtures and simple substances:

- A mixture in which the composition ratio of each component in the cashew-derived mixture has been adjusted - A single entity in which only a specific component is isolated from the cashew-derived mixture - A mixture containing a modified product obtained by modifying a component in the cashew-derived mixture - A mixture containing a polymer obtained by polymerizing a component in the cashew-derived mixture - A mixture containing a modified polymer obtained by modifying and polymerizing a component in the cashew-derived mixture - A mixture containing a modified product obtained by further modifying a component in the mixture in which the composition ratio has been adjusted - A mixture containing a polymer obtained by further polymerizing a component in the mixture in which the composition ratio has been adjusted - A mixture containing a modified polymer obtained by further modifying and polymerizing a component in the mixture in which the composition ratio has been adjusted - A modified product obtained by further modifying the isolated single entity - A polymer obtained by further polymerizing the isolated single entity - A modified polymer obtained by further modifying and polymerizing the isolated single entity Here, the single entity also includes polymers such as dimers and trimers.

From the viewpoint of improving the biodegradation rate of the resin particles, it is preferable that the cardanol compound (B1) is at least one compound selected from the group consisting of compounds represented by general formula (CDN1) and polymers obtained by polymerizing the compounds represented by general formula (CDN1).

In the general formula (CDN1), R ¹ represents an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. R ² represents a hydroxyl group, a carboxyl group, an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. P2 represents an integer of 0 to 4. When P2 is 2 or more, the multiple R ^2s may be the same group or different groups.

In general formula (CDN1), the alkyl group which may have a substituent represented by R ¹ is preferably an alkyl group having 3 to 30 carbon atoms, more preferably an alkyl group having 5 to 25 carbon atoms, and further preferably an alkyl group having 8 to 20 carbon atoms.
Examples of the substituent include a hydroxy group; a substituent containing an ether bond, such as an epoxy group or a methoxy group; and a substituent containing an ester bond, such as an acetyl group or a propionyl group.
Examples of the alkyl group which may have a substituent include a pentadecane-1-yl group, a heptan-1-yl group, an octan-1-yl group, a nonan-1-yl group, a decan-1-yl group, an undecane-1-yl group, a dodecane-1-yl group, and a tetradecane-1-yl group.

In general formula (CDN1), the unsaturated aliphatic group represented by R ¹ which has a double bond and which may have a substituent 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 unsaturated aliphatic group preferably has 1 or more and 3 or less double bonds.
Examples of the substituent include those exemplified as the substituent for the alkyl group.
Examples of the unsaturated aliphatic group having a double bond and optionally having a substituent include a pentadec-8-en-1-yl group, a pentadeca-8,11-dien-1-yl group, a pentadeca-8,11,14-trien-1-yl group, a pentadec-7-en-1-yl group, a pentadeca-7,10-dien-1-yl group, and a pentadeca-7,10,14-trien-1-yl group.

In the general formula (CDN1), R ¹ is preferably a pentadec-8-en-1-yl group, a pentadeca-8,11-dien-1-yl group, a pentadeca-8,11,14-trien-1-yl group, a pentadec-7-en-1-yl group, a pentadeca-7,10-dien-1-yl group, or a pentadeca-7,10,14-trien-1-yl group.

In general formula (CDN1), preferred ^examples of the alkyl group which may have a substituent and the unsaturated aliphatic group which has a double bond and may have a substituent, represented by ^R2 , include the same as those exemplified above as the alkyl group which may have a substituent and the unsaturated aliphatic group which has a double bond and may have a substituent, represented by R1.

The compound represented by the general formula (CDN1) may be further modified. For example, it may be epoxidized. From the viewpoint of improving the biodegradation rate of the resin particles, it is preferable that the compound represented by the general formula (CDN1) has a structure in which the hydroxy group is replaced with the following group (EP), that is, the compound represented by the general formula (CDN1-e) below.

In the group (EP) and general formula (CDN1-e), L _EP represents a single bond or a divalent linking group. In general formula (CDN1-e), R ¹ , R ² and P2 have the same meanings as R ¹ , R ² and P2 in general formula (CDN1), respectively.

In the group (EP) and the general formula (CDN1-e), examples of the divalent linking group represented by L _EP 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 -CH ₂ CH ₂ OCH ₂ CH ₂ - group, and the like.
Examples of the substituent include the same as those exemplified as the substituent for R ¹ in formula (CDN1).

_LEP is preferably a methylene group.

A polymer formed by polymerizing a compound represented by general formula (CDN1) refers to a polymer formed by polymerizing at least two or more compounds represented by general formula (CDN1) with or without a linking group.

An example of a polymer formed by polymerizing a compound represented by general formula (CDN1) is a compound represented by the following general formula (CDN2).

In the general formula (CDN2), R ¹¹ , R ¹² and R ¹³ each independently represent an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. R ²¹ , R ²² and R ²³ each independently represent a hydroxyl group, a carboxyl group, an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. P21 and P23 each independently represent an integer of 0 to 3, and P22 represents an integer of 0 to 2. ^{L 1} and L ² each independently represent a divalent linking group. n represents an integer of 0 to 10. When P21 is 2 or more, a plurality of R ²¹ , when P22 is 2 or more, a plurality of R ²² , and when P23 is 2 or more, a plurality of R ²³ may each be the same group or different groups. When n is 2 or more, the multiple R ¹² , R ²² and L ¹ may be the same or different groups, and when n is 2 or more, the multiple P22 may be the same or different numbers.

In general formula (CDN2), preferred examples of the alkyl group which may have a substituent and the unsaturated aliphatic group which has a double bond and may have a substituent represented by R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ^{22 and} R 23 include those listed as R ¹ in general formula (CDN1).

In general formula (CDN2), examples of the divalent linking group represented by ^L1 and ^L2 include 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).
Examples of the substituent include the same as those exemplified as the substituent for R ¹ in formula (CDN1).

In general formula (CDN2), n is preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less.

The compound represented by the general formula (CDN2) may be further modified. For example, it may be epoxidized, specifically, a compound in which the hydroxy group of the compound represented by the general formula (CDN2) is replaced with a group (EP), that is, a compound represented by the following general formula (CDN2-e).

In general formula (CDN2-e), R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² , R ²³ , P21, P22, P23, L ¹ , L ² and n are each synonymous with R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² , R ²³ , P21, P22, P23, L ¹ , L ² and n in general formula (CDN2), respectively.
In formula (CDN2-e), L _EP1 , L _EP2 and L _EP3 each independently represent a single bond or a divalent linking group. When n is 2 or more, a plurality of L _EP2's may be the same or different groups.

In general formula (CDN2-e), preferred examples of the divalent linking group represented by L _EP1 , L _EP2 and L _EP3 include those recited as the divalent linking group represented by L _EP in general formula (CDN1-e).

The polymer formed by polymerization of the compound represented by the general formula (CDN1) may be, for example, a polymer formed by three-dimensional cross-linking polymerization of at least three or more compounds represented by the general formula (CDN1) with or without a linking group. The polymer formed by three-dimensional cross-linking polymerization of the compound represented by the general formula (CDN1) may be, for example, a compound represented by the following structural formula.

In the above structural formula, R ¹⁰ , R ²⁰ and P20 are the same as R ¹ , R ² and P2 in general formula (CDN1). L ¹⁰ represents a single bond or a divalent linking group. A plurality of R ¹⁰ , R ²⁰ and L ¹⁰ may be the same group or different groups. A plurality of P ²⁰ may be the same number or different numbers.

In the above structural formula, examples of the divalent linking group represented by ^L10 include 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).
Examples of the substituent include the same as those exemplified as the substituent for R ¹ in formula (CDN1).

The compound represented by the above structural formula may be further modified, for example, epoxidized. Specifically, the compound may have a structure in which the hydroxyl group of the compound represented by the above structural formula is replaced with a group (EP), and examples thereof include the compound represented by the following structural formula, that is, a polymer in which the compound represented by the general formula (CDN1-e) is three-dimensionally cross-linked and polymerized.

In the above structural formula, R ¹⁰ , R ²⁰ and P20 are respectively defined as R ¹ , R ² and P2 in general formula (CDN1-e). L ¹⁰ represents a single bond or a divalent linking group. A plurality of R ¹⁰ , R ²⁰ and L ¹⁰ may be the same group or different groups. A plurality of P ²⁰ may be the same number or different numbers.

In the above structural formula, examples of the divalent linking group represented by ^L10 include 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).
Examples of the substituent include the same as those exemplified as the substituent for R ¹ in formula (CDN1).

From the viewpoint of improving the transparency of the resin molded body, the cardanol compound (B1) preferably contains a cardanol compound (B1) having an epoxy group, and is more preferably a cardanol compound (B1) having an epoxy group.

As the cardanol compound (B1), commercially available products may be used. Examples of commercially available products include NX-2024, Ultra LITE 2023, NX-2026, GX-2503, NC-510, LITE 2020, NX-9001, NX-9004, NX-9007, NX-9008, NX-9201, and NX-9203 manufactured by Cardolite Corporation, and LB-7000, LB-7250, and CD-5L manufactured by Tohoku Kako Co., Ltd. Examples of commercially available cardanol compounds having an epoxy group include NC-513, NC-514S, NC-547, LITE513E, and Ultra LTE 513 manufactured by Cardolite Corporation.

From the viewpoint of improving the biodegradation rate of the resin molded body, the hydroxyl value of the cardanol compound (B1) is preferably 100 mgKOH/g or more, more preferably 120 mgKOH/g or more, and even more preferably 150 mgKOH/g or more. The hydroxyl value of the cardanol compound (B1) is measured according to ISO 14900 Method A.

When a cardanol compound (B1) having an epoxy group is used as the cardanol compound (B1), the epoxy equivalent is preferably 300 or more and 500 or less, more preferably 350 or more and 480 or less, and even more preferably 400 or more and 470 or less, from the viewpoint of improving the transparency of the resin molded product. The epoxy equivalent of the cardanol compound (B1) having an epoxy group is measured in accordance with ISO 3001.

From the viewpoint of improving the biodegradation rate of the resin molded article, the molecular weight of the cardanol compound (B1) is preferably 250 or more and 1,000 or less, more preferably 280 or more and 800 or less, and even more preferably 300 or more and 500 or less.

The cardanol compound (B1) may be used alone or in combination of two or more.

(Ester compound (C): component (C))
The ester compound (C) has an ester group and a long-chain hydrocarbon group.

A long-chain hydrocarbon group is a hydrocarbon group with 8 or more carbon atoms.

From the viewpoint of improving resistance to hydrolysis in water, the number of carbon atoms in the long-chain hydrocarbon group is preferably 12 or more and 20 or less, more preferably 13 or more and 19 or less, and even more preferably 14 or more and 18 or less.

The long-chain hydrocarbon group may be a saturated or unsaturated hydrocarbon group, but is preferably a saturated hydrocarbon group.

The long-chain hydrocarbon group may be linear, branched, or cyclic, but is preferably linear or branched, and more preferably linear.

The long-chain hydrocarbon group may be a group in which the hydrogen atoms in the long-chain hydrocarbon group are substituted with halogen atoms (e.g., fluorine atoms, bromine atoms, iodine atoms), oxygen atoms, nitrogen atoms, etc., but is preferably unsubstituted.

Specific examples of the long-chain hydrocarbon group include octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl (cetyl), heptadecyl, octadecyl (stearyl), nonadecyl, and eicosyl groups.
From the viewpoint of improving resistance to hydrolysis in water, the long-chain hydrocarbon group is preferably a hexadecyl group (cetyl group) or an octadecyl group (stearyl group), and more preferably an octadecyl group (stearyl group).

From the viewpoint of improving resistance to hydrolysis in water, it is preferable that the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups.

When the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups, the number of carbon atoms in the long-chain hydrocarbon groups is preferably 12 or more and 20 or less, more preferably 13 or more and 19 or less, and even more preferably 14 or more and 18 or less, from the viewpoint of improving resistance to hydrolysis in water.

When the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups, it is preferable that at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 17 to 20 carbon atoms, and at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 15 to 18 carbon atoms, it is more preferable that at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 18 or 19 carbon atoms, and at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 16 to 18 carbon atoms, it is even more preferable that at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 18 carbon atoms, and at least one of the two or more long-chain hydrocarbon groups is a long-chain hydrocarbon group having 16 or 18 carbon atoms.

Specifically, for example, when the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups, it is preferable that at least one of the two or more long-chain hydrocarbon groups is a heptadecyl group, an octadecyl group (stearyl group), a nonadecyl group, or an eicosyl group, and at least one of the two or more long-chain hydrocarbon groups is a pentadecyl group, a hexadecyl group (cetyl group), a heptadecyl group, or an octadecyl group (stearyl group), and at least one of the two or more long-chain hydrocarbon groups is a pentadecyl group, a hexadecyl group (cetyl group), a heptadecyl group, or an octadecyl group (stearyl group). It is more preferable that one of the two or more long-chain hydrocarbon groups is an octadecyl group (stearyl group) or a nonadecyl group, and at least one of the two or more long-chain hydrocarbon groups is a hexadecyl group (cetyl group), a heptadecyl group, or an octadecyl group (stearyl group), and it is even more preferable that at least one of the two or more long-chain hydrocarbon groups is an octadecyl group (stearyl group), and at least one of the two or more long-chain hydrocarbon groups is a hexadecyl group (cetyl group) or an octadecyl group (stearyl group).

Specific examples of the ester compound having two or more long-chain hydrocarbon groups include pentadecyl stearate, cetyl stearate, heptadecyl stearate, and stearyl stearate.
From the viewpoint of improving the hydrolysis resistance of the resin particles in water, the ester compound having two or more long chain hydrocarbon groups is preferably at least one of cetyl stearate and stearyl stearate.

The ester compound (C) may be used alone or in combination of two or more types.

(Content or mass ratio of components (A) to (C))
Mass ratio of component (A) to component (B) ((B)/(A))
The mass ratio of component (A) to component (B) ((B)/(A)) is 0.15 or more and 0.8 or less.

If the mass ratio ((B)/(A)) is less than 0.15, the thermal decomposition action of component (A) by component (B) becomes insufficient, and a high biodegradation rate cannot be obtained.
Therefore, the mass ratio ((B)/(A)) is set to 0.15 or more.
However, if the mass ratio ((B)/(A)) exceeds 0.8, the biodegradation rate becomes too fast, and the durability of the resin particles when used in water may decrease. Therefore, from the viewpoint of suppressing an excessive biodegradation rate, the mass ratio ((B)/(A)) is set to 0.80 or less.

From the viewpoint of improving the biodegradation rate while maintaining the durability of the resin particles during use, the mass ratio ((B)/(A)) is preferably 0.20 or more and 0.40 or less, and more preferably 0.20 or more and 0.35 or less.

Mass ratio of component (A) to component (C) ((C)/(A))
The mass ratio of component (A) to component (C) ((C)/(A)) is 0.02 or more and 0.10 or less.

If the mass ratio ((C)/(A)) is less than 0.02, the amount of component (C) oriented on the surface of the resin particles will be small, and resistance to hydrolysis in water will decrease. Therefore, the mass ratio ((C)/(A)) is set to 0.02 or more.
However, if the mass ratio ((C)/(A)) exceeds 0.10, the component (C) will be in excess, and the component (C) will tend to aggregate and crystallize. As a result, the layer of component (C) formed on the surface will tend to crack, and resistance to hydrolysis in water will decrease. Therefore, the mass ratio ((C)/(A)) is set to 0.10 or less.

From the viewpoint of improving the hydrolysis resistance of the resin particles in water, the mass ratio ((C)/(A)) is preferably 0.03 or more and 0.07 or less, and more preferably 0.04 or more and 0.05 or less.

--Content of component (A)--
From the viewpoint of improving the biodegradation rate, it is preferable to contain the component (A) as a main component.
Here, the component (A) being the main component means that the mass ratio of the component (A) to the entire resin particles is the largest.

Specifically, the total amount of component (A) is preferably 50% by mass or more and 90% by mass or less, more preferably 53% by mass or more and 85% by mass or less, and even more preferably 60% by mass or more and 82% by mass or less, based on the total amount of the resin particles.

(Other ingredients)
The resin particles according to this embodiment may contain other components.
Examples of other components include plasticizers, flame retardants, compatibilizers, release agents, light resistance agents, weather resistance agents, colorants, pigments, modifiers, anti-drip agents, antistatic agents, hydrolysis inhibitors, fillers, reinforcing agents (glass fibers, carbon fibers, talc, clay, mica, glass flakes, milled glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.), acid acceptors for preventing release of acetic acid (oxides such as magnesium oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and hydrotalcite; calcium carbonate; talc; etc.), and reactive trapping agents (for example, epoxy compounds, acid anhydride compounds, carbodiimides, etc.).
The content of each of the other components is preferably 0% by mass or more and 5% by mass or less based on the total amount of the resin particles, where "0% by mass" means that no other components are included.

The resin particles according to the present embodiment may contain other resins other than the component (A) and the component (B). However, when the other resins are contained, the content of the other resins relative to the total amount of the resin particles is preferably 5% by mass or less, and preferably less than 1% by mass. It is more preferable that the other resins are not contained (i.e., 0% by mass).
Examples of other resins include conventionally known thermoplastic resins, specifically, polycarbonate resins; polypropylene resins; polyester resins; polyolefin resins; polyester carbonate resins; polyphenylene ether resins; polyphenylene sulfide resins; polysulfone resins; polyethersulfone resins; polyarylene resins; polyetherimide resins; polyacetal resins; polyvinyl acetal resins; polyketone resins; polyether ketone resins; polyether ether ketone resins; polyaryl ketone resins; polyether nitrile resins; liquid crystal resins; polybenzimidazole resins; polypa Examples of the resin include lavane acid resins, vinyl polymers or copolymers obtained by polymerizing or copolymerizing one or more vinyl monomers selected from the group consisting of aromatic alkenyl compounds, methacrylic acid esters, acrylic acid esters, and vinyl cyanide compounds, diene-aromatic alkenyl compound copolymers, vinyl cyanide-diene-aromatic alkenyl compound copolymers, aromatic alkenyl compound-diene-vinyl cyanide-N-phenylmaleimide copolymers, vinyl cyanide-(ethylene-diene-propylene (EPDM))-aromatic alkenyl compound copolymers, vinyl chloride resins, and chlorinated vinyl chloride resins. These resins may be used alone or in combination of two or more.

(Mass reduction rate)
The resin particles according to this embodiment have a mass loss rate of 30% or less after 90 days in water at 50° C. and pH 7.8.
When the mass loss rate is 30% or less, the resin particles have improved resistance to hydrolysis in water.

The mass reduction rate is preferably 0% or more and 26% or less, more preferably 0% or more and 16% or less, even more preferably 0% or more and 11% or less, and most preferably 0% or more and 5% or less.

The mass loss rate is measured according to the procedure described in the Examples below.

(Hydrophobicity)
The resin particles according to this embodiment have a hydrophobicity of 30 or more as measured by the following method.
When the hydrophobicity is 30 or more, the resin particles have improved resistance to hydrolysis in water.

The hydrophobicity is preferably 30 or more and 95 or less, more preferably 35 or more and 90 or less, and even more preferably 40 or more and 85 or less.

The hydrophobicity is measured as follows.
(Method of measuring hydrophobicity)
50 g of distilled water is placed in a 300 ml beaker and stirred with a stirrer. 0.2 g of resin particles are placed in the beaker and dispersed in the distilled water. Methanol is dripped into the beaker with a dropper. The amount of methanol dripped when all the resin particles have settled is defined as Me (g), and the hydrophobicity is calculated by the following formula.
Hydrophobicity=Me/(Me+50)

(Shape of resin particles)
From the viewpoint of improving the resistance of the resin particles to hydrolysis in water, the resin particles according to this embodiment preferably have a volume average particle size of, for example, 3 μm or more and 100 μm or less.
The volume average particle size of the resin particles is more preferably from 5 μm to 50 μm, and further preferably from 8 μm to 30 μm.

From the viewpoint of improving the hydrolysis resistance of the resin particles in water, the large diameter particle size distribution index GSDv of the resin particles is, for example, preferably 1.50 or less, more preferably 1.30 or less, and even more preferably 1.20 or less.

The volume average particle size and the large particle size distribution index GSDv of the resin particles are measured as follows.
The particle size is measured using an LS particle size distribution measuring device "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 50% of the cumulative distribution is determined as the volume average particle size.
On the other hand, the cumulative particle size distribution is plotted from the small diameter side on a volume basis, and the particle size at 50% of the cumulative distribution is defined as the number average particle size D50v, and the particle size at 84% of the cumulative distribution is defined as the number particle size D84v. The large diameter side number particle size distribution index GSDv is calculated by the formula GSDv = (D84v/D50v) ^1/2 .

The resin particles can be produced, for example, by the following method.
1) A kneading and grinding method in which the components are kneaded, and the resulting kneaded product is ground and classified to obtain resin particles;
2) A dry manufacturing method in which granules obtained by the kneading and grinding method are changed in shape by mechanical impact force or thermal energy to obtain resin particles. 3) An aggregation and coalescence method in which particle dispersions of each component are mixed, the particles in the dispersion are aggregated and heat-fused to obtain resin particles. 4) A dissolution and suspension method in which an organic solvent in which each component is dissolved is suspended in an aqueous solvent to granulate resin particles containing each component.

Among these, wet methods such as the aggregation/coalescence method and the dissolution/suspension method are preferable from the viewpoint of obtaining resin particles having a volume average particle size and a large particle size distribution index GSDv within the above range.

Applications of the resin particles according to this embodiment include cosmetic base materials, rolling agents, abrasives, scrubbing agents, display spacers, materials for forming beads, light diffusing particles, resin reinforcing agents, refractive index control agents, biodegradation accelerators, fertilizers, water-absorbing particles, and granular toner particles.

The resin particles according to this embodiment will be described in more detail below with reference to examples. The materials, amounts used, ratios, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the resin particles according to this embodiment should not be interpreted as being limited by the specific examples shown below.

Here, "*" in Tables 1 to 4 means that it is outside the scope of the preferred embodiment of the present invention.

<Preparing each ingredient>
The following materials were prepared:

(Component (A))
CA1: Eastman Chemical "CAP482-20", cellulose acetate propionate, weight average degree of polymerization 716, acetyl group substitution degree 0.18, propionyl group substitution degree 2.49.
CA2: Eastman Chemical "CAB381-20", cellulose acetate butyrate, weight average degree of polymerization 595, acetyl group substitution degree 0.15, butyryl group substitution degree 1.74.
CA3: Daicel "L-20", cellulose acetate, weight average degree of polymerization 450, degree of acetyl group substitution 2.50.

(Component (B))
PHC1: Cardolite "NX-2503", hydroxyethylated cardanol, molecular weight 296-320
PHC2: Cardolite "Ultra LITE 513", glycidyl ether of cardanol, molecular weight 354-361.
・PHC3: Idemitsu Showa Shell "Bisphenol A"
・PHC4: Tokyo Chemical Industry "Phenol"
・PHC5: Mitsubishi Chemical "ODA", dioctyl adipate

(Component (C))
EC1: Kao "Excelpearl SS", stearyl stearate EC2: Tokyo Chemical Industry "Cetyl stearate"
EC3: High Alcohol Industry "EHC", 2-ethylhexanoic acid cetyl EC4: Tokyo Chemical Industry "Ethyl Acetate"
EC5: dodecyl octylate EC6: dodecyl icosylate EC7: dodecyl henosylate

<Preparation of resin pellets RE1 to RE30>
The cylinder temperature was adjusted based on the charged composition ratios shown in Tables 1 and 2, and kneading was performed using a twin-screw kneader (TEX41SS, manufactured by Toshiba Machine Co., Ltd.) to produce pellet-shaped resins RE1 to RE30 (hereinafter referred to as resin pellets RE1 to RE30).
In Table 2, "-" indicates that the corresponding component is not contained, or that the corresponding value has not been calculated because component (B) or component (C) is not contained.

Example 1
(Preparation of resin particles RPC1)
300 parts by mass of resin pellets (RE1) are completely dissolved in 700 parts by mass of methyl ethyl ketone. This is added to an aqueous liquid in which 100 parts by mass of calcium carbonate, 4 parts by mass of carboxymethyl cellulose, and 200 parts by mass of methyl ethyl ketone are dispersed in 1100 parts by mass of pure water, and stirred for 3 hours. 10 parts by mass of sodium hydroxide is added to this, heated to 80°C, and stirred for 3 hours to remove methyl ethyl ketone. After filtering the residue, the solid content is freeze-dried to obtain resin particles RPC1.

<Examples 2 to 27 and Comparative Examples 1 to 12>
(Preparation of resin particles RPC2 to 37)
Resin particles RPC2 to 37 were obtained in the same manner as resin particle RPC1, except that the resin pellets, the amount of each component in the aqueous liquid (amount of calcium carbonate, amount of carboxymethyl cellulose, amount of methyl ethyl ketone), the stirring time of the aqueous liquid, and the amount of sodium hydroxide added were changed according to Tables 3 and 4.

(Preparation of resin particles RPC38 and 39)
Commercially available cellulose-based particles, CELLULOBEADS D10 (manufactured by Daito Kasei) were prepared as resin particles RPC38, and BELLOCEA (manufactured by Daicel) was prepared as resin particles RPC39.

<Particle size, particle size distribution, hydrophobicity>
According to the method described above, the volume average particle size and the large particle size distribution index GSDv of the resin particles were measured using a LS particle size distribution measuring device Beckman Coulter LS13 320 (manufactured by Beckman Coulter, Inc.).
The degree of hydrophobicity was measured according to the method already described.

<Mass reduction rate>
The mass loss rate of the obtained resin particles was measured by the following procedure.

- Measurement of mass loss rate of resin particles -
50 g of the obtained resin particles were sealed in a bag made of #508/585-1μ nylon mesh (mesh size 1 μm) and immersed in distilled water adjusted to 50° C. and pH 7.8 for 90 days. Thereafter, the nylon mesh containing the resin particles was removed, and the resin particles in the nylon mesh were vacuum-dried. The mass of the resin particles after vacuum drying was measured, and the mass reduction rate of the resin particles was measured.

<Measurement of biodegradability>
Using the obtained resin particles, the aerobic biodegradability was measured according to a method conforming to ISO-14855-2 (2018), and the anaerobic biodegradability was measured according to a method conforming to ISO-14853 (2016). The time required to reach a biodegradability of 50% and 90% was evaluated as the biodegradation rate.

The above results show that the resin particles of this example are biodegradable and have excellent resistance to hydrolysis in water.

Claims (12)

Cellulose acylate (A),
an aromatic compound (B) which does not have a functional group reactive with the cellulose acylate (A) and has, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
(C) an ester compound having a long chain hydrocarbon group,
a mass ratio ((B)/(A)) of the cellulose acylate (A) to the aromatic compound (B) is 0.15 or more and 0.8 or less;
a mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is 0.03 or more and 0.10 or less;
The acyl group contained in the cellulose acylate (A) is an unsubstituted acyl group,
the resin particles do not contain any other resin than the cellulose acylate (A) and the aromatic compound (B), or the content of the other resin is 5% by mass or less based on the total amount of the resin particles;
The resin particles have a volume average particle size of 3 μm or more and 100 μm or less,
The resin particles have a large particle size distribution index GSDv of 1.50 or less . The resin particles according to claim 1, wherein the cellulose acylate (A) is a cellulose acylate having two or more types of acyl groups. The resin particles according to claim 1 or 2, wherein the aromatic compound (B) is a cardanol compound (B1). The resin particles according to claim 3, wherein the cardanol compound (B1) is at least one compound selected from the group consisting of compounds represented by the following general formula (CDN1) and compounds represented by the following general formula (CDN1-e):

(In general formula (CDN1), R ¹ represents an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. R ² represents a hydroxy group, a carboxy group, an alkyl group which may have a substituent, or an unsaturated aliphatic group which has a double bond and may have a substituent. P 2 represents an integer of 0 to 4. When P 2 is 2 or more, a plurality of R ^2s may be the same group or different groups.)

(In general formula (CDN1-e), L _EP represents a single bond or a divalent linking group. In general formula (CDN1-e), R ¹ , R ² and P2 have the same meanings as R ¹ , R ² and P2 in general formula (CDN1), respectively.) The resin particles according to any one of claims 1 to 4, wherein the ester compound (C) is an ester compound having two or more long-chain hydrocarbon groups. The resin particles according to claim 5, wherein the two or more long chain hydrocarbon groups of the ester compound (C) are hydrocarbon groups having 8 to 20 carbon atoms. The resin particles according to claim 6, wherein at least one of the two or more hydrocarbon groups having 8 to 20 carbon atoms contained in the ester compound (C) is a stearyl group. The mass ratio of the cellulose acylate (A) to the aromatic compound (B) ((B)/(A))
The resin particles according to any one of claims 1 to 7, wherein the value is 0.20 or more and 0.40 or less. The resin particles according to any one of claims 1 to 8, wherein the mass ratio ((C)/(A)) of the cellulose acylate (A) to the ester compound (C) is 0.03 or more and 0.07 or less. Cellulose acylate (A),
an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
(C) an ester compound having a long chain hydrocarbon group,
The mass loss rate after 90 days in water at 50°C and pH 7.8 is 16% or less,
The acyl group contained in the cellulose acylate (A) is an unsubstituted acyl group,
The resin particles have a volume average particle size of 3 μm or more and 100 μm or less,
The resin particles have a large particle size distribution index GSDv of 1.50 or less . Cellulose acylate (A),
an aromatic compound (B) having, together with a long-chain aliphatic group, at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to an aromatic group;
(C) an ester compound having a long chain hydrocarbon group,
The hydrophobicity measured by the following method is 50 or more,
The acyl group contained in the cellulose acylate (A) is an unsubstituted acyl group,
The resin particles have a volume average particle size of 3 μm or more and 100 μm or less,
The resin particles have a large particle size distribution index GSDv of 1.50 or less .
(Method of measuring hydrophobicity)
50 g of distilled water is placed in a 300 ml beaker and stirred with a stirrer. 0.2 g of resin particles are placed in the beaker and dispersed in the distilled water. Methanol is dripped into the beaker with a dropper. The amount of methanol dripped when all the resin particles have settled is defined as Me (g), and the hydrophobicity is calculated by the following formula.
Hydrophobicity=Me/(Me+50) The resin particles according to any one of claims 1 to 11 , wherein the acyl group of the cellulose acylate (A) is at least one selected from the group consisting of an acetyl group, a propionyl group, a butyryl group, and a hexanoyl group.