阅读说明：本技术 生物降解性树脂颗粒 (Biodegradable resin particle ) 是由 大木正启 八百健二 吉川英昭 岩永猛 吉田和世 田口哲也 于 2021-06-04 设计创作，主要内容包括：本发明提供一种生物降解性树脂颗粒,其具有：包含生物降解性树脂的母颗粒；存在于上述母颗粒表面上的包含聚烯化亚胺、聚烯丙胺和聚乙烯胺中的至少一种阳离子性树脂的第一层；以及存在于上述第一层上的包含阴离子型或非离子型疏水性化合物的第二层。(The present invention provides a biodegradable resin particle having: a mother particle containing a biodegradable resin; a first layer containing at least one cationic resin selected from the group consisting of polyalkyleneimine, polyallylamine, and polyvinylamine, which is present on the surface of the mother particle; and a second layer comprising an anionic or nonionic hydrophobic compound present on the first layer.)

1. A biodegradable resin particle having:

a mother particle containing a biodegradable resin;

a first layer containing at least one cationic resin selected from the group consisting of polyalkyleneimine, polyallylamine, and polyvinylamine, which is present on the surface of the mother particle; and

a second layer comprising an anionic or nonionic hydrophobic compound present on the first layer.

2. The biodegradable resin particle according to claim 1, wherein said hydrophobic compound is at least one selected from the group consisting of a siloxane compound, a hydrocarbon compound, a fatty acid compound, an acrylic resin, a polyester resin, and a urethane resin.

3. The biodegradable resin particle according to claim 2, wherein said silicone compound is at least one member selected from the group consisting of dimethylpolysiloxane, methylpolysiloxane, MQ resin, and silicone rubber.

4. The biodegradable resin particle according to claim 2 or 3, wherein said hydrocarbon compound is at least one selected from the group consisting of paraffin wax, microcrystalline wax, polyethylene wax, and polypropylene wax.

5. The biodegradable resin particle according to any one of claims 2 to 4, wherein said fatty acid compound is at least one selected from the group consisting of carnauba wax, rice bran wax, candelilla wax, palm wax, castor oil wax, soybean oil wax, and sunflower oil wax.

6. The biodegradable resin particle according to claim 1-5, wherein said polyalkyleneimine is a polyalkyleneimine having a structural unit containing an alkylene group having 1-4 carbon atoms.

7. The biodegradable resin particle according to claim 6, wherein said polyalkyleneimine having a structural unit containing an alkylene group having 1 to 4 carbon atoms is a polyethyleneimine.

8. The biodegradable resin particle according to any one of claims 1 to 7, wherein said biodegradable resin is at least one selected from the group consisting of a cellulose resin and a polyester resin.

9. The biodegradable resin particle according to claim 8, wherein said biodegradable resin is a cellulose resin.

10. The biodegradable resin particle according to claim 9, wherein said cellulose resin is a cellulose acylate having two or more acyl groups.

11. The biodegradable resin particle according to claim 9 or 10, wherein said mother particle comprises at least one of an aromatic compound and a fatty acid ester,

the aromatic compound has no functional group that reacts with the cellulose resin, has a long-chain aliphatic group, and has at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to the aromatic group.

12. The biodegradable resin particle according to claim 11, wherein said aromatic compound is a cardanol compound.

13. The biodegradable resin particle according to claim 12, wherein said cardanol compound is at least one compound selected from the group consisting of a compound represented by general formula (CDN1) and a compound represented by general formula (CDN1-e),

[ solution 1]

In the general formula (CDN1), R¹Represents an alkyl group with or without a substituent, or an unsaturated group with or without a substituent and having a double bondAn aliphatic group; r²Represents a hydroxyl group, a carboxyl group, an alkyl group with or without a substituent, or an unsaturated aliphatic group with a double bond and with or without a substituent; p2 represents an integer of 0 to 4 inclusive; when P2 is 2 or more, plural Rs²Can be the same group or different groups;

[ solution 2]

In the general formula (CDN1-e), L_EPRepresents a single bond or a 2-valent linking group; in the general formula (CDN1-e), R¹、R²And P2 with R in formula (CDN1), respectively¹、R²And P2.

14. The biodegradable resin particle according to any one of claims 11 to 13, wherein said mother particle contains cellulose acetate-propionate as said cellulose resin and a cardanol compound as said aromatic compound.

15. The biodegradable resin particle according to any one of claims 11 to 13, wherein said mother particle contains cellulose acetate butyrate and said fatty acid ester as said cellulose resin.

16. The biodegradable resin particle according to any one of claims 1 to 15, wherein a mass ratio of a content of said cationic resin in said first layer to a content of said hydrophobic compound in said second layer is 0.1 to 10.

17. The biodegradable resin particle according to claim 16, wherein a content of said cationic resin in said parent particle is 0.1% by mass or more and 10% by mass or less.

18. The biodegradable resin particle according to any one of claims 1-17, wherein said cationic resin has a number average molecular weight of 10000 or more and 85000 or less.

19. A biodegradable resin particle having:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

the water contact angle of pellets obtained by pelletizing biodegradable resin particles is 70 DEG to 120 deg.

20. A biodegradable resin particle having:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

the aerobic biodegradation rate after 3 months as determined by a method according to ISO-14855-2 (2018) is 20% or less.

21. A biodegradable resin particle having:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

when the surface of the biodegradable resin particle is measured by X-ray photoelectron spectroscopy, the relationship among the carbon atomic weight Cs, the silicon atomic weight Sis and the oxygen atomic weight Os satisfies the formula A: (Cs + Sis)/Os ≧ 3.

22. The biodegradable resin particle according to claim 21, wherein a relationship among a carbon atomic weight Ce, a silicon atomic weight Sie, and an oxygen atomic weight Oe, when measured by X-ray photoelectron spectroscopy on a surface of said biodegradable resin particle after being subjected to surface etching for 3 minutes, satisfies formula B: (Ce + Sie)/Oe ≧ 3.

Technical Field

The present invention relates to biodegradable resin particles.

Background

Patent document 1 discloses "a cellulose material having improved biodegradability by being coated with a water-soluble polymer".

Patent document 1 discloses polyethyleneimine as a water-soluble polymer.

Patent document 2 discloses a "cosmetic method for changing the appearance of skin, changing the feel of skin, and/or protecting skin, which comprises a step of applying a self-supporting cosmetic sheet comprising at least 1 biocompatible and/or biodegradable hydrophobic polymer layer, the self-supporting cosmetic sheet having a thickness of 10 to 1000nm, preferably 30 to 500nm, more preferably 50 to 300nm, to the skin.

Patent document 2 discloses a layer containing polyethyleneimine as a hydrophobic polymer layer.

Patent document 3 discloses "a biodegradable resin composition obtained by compounding (a) a thermoplastic synthetic resin, (B) an inorganic filler, and (C) a biodegradable organic substance, wherein the amount of the component (a) is 49% by mass or less based on the total amount of the composition, and the compounding ratio of the component (B) to the component (C) ((B)/(C)) is in the range of 3/7 to 7/3 by mass ratio".

Patent document 3 discloses that at least one selected from the group consisting of liquid paraffin, metal soap, siloxane, side chain crystalline polyolefin, stearic acid, and polyglutamic acid is blended as the binder component (D) in the biodegradable resin composition.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-256579

Patent document 2: japanese laid-open patent publication No. 2015-512863

Patent document 3: japanese patent laid-open publication No. 2011-225643

Disclosure of Invention

Technical problem to be solved by the invention

An object of the present invention is to provide biodegradable resin particles having a temporal biodegradation rate (biodegradation rate) and a low initial biodegradation rate (initial biodegradation rate) as compared with biodegradable resin particles having only a layer containing at least one cationic resin selected from the group consisting of polyalkyleneimine, polyallylamine, and polyvinylamine on the surface of a mother particle containing a biodegradable resin.

Means for solving the problems

Specific means for solving the above technical problems include the following means.

<1> a biodegradable resin particle comprising:

a mother particle containing a biodegradable resin;

a first layer containing at least one cationic resin selected from the group consisting of polyalkyleneimine (polyalkyleneimine), polyallylamine (polyallylamine), and polyvinylamine (polyvinylamine) present on the surface of the above-mentioned mother particle; and

a second layer comprising an anionic or nonionic hydrophobic compound present on the first layer.

<2> the biodegradable resin particle according to <1>, wherein the hydrophobic compound is at least one selected from the group consisting of silicone compounds, hydrocarbon compounds, fatty acid compounds, acrylic resins, polyester resins, and urethane resins.

<3> the biodegradable resin particle according to <2>, wherein the silicone compound is at least one selected from the group consisting of dimethylpolysiloxane, methylpolysiloxane, MQ resin, and silicone rubber.

<4> the biodegradable resin particle according to <2> or <3>, wherein the hydrocarbon compound is at least one selected from the group consisting of paraffin wax, microcrystalline wax, polyethylene wax and polypropylene wax.

<5> the biodegradable resin particle according to any one of <2> to <4>, wherein the fatty acid compound is at least one selected from the group consisting of carnauba wax, rice bran wax, candelilla wax, palm wax, castor oil wax, soybean oil wax, and sunflower oil wax.

<6> the biodegradable resin particle according to any one of <1> to <5>, wherein the polyalkyleneimine has a structural unit containing an alkylene group having 1 to 4 carbon atoms.

<7> the biodegradable resin particle according to <6>, wherein the polyalkyleneimine having a structural unit containing an alkylene group having 1 to 4 carbon atoms is polyethyleneimine.

<8> the biodegradable resin particle according to any one of <1> to <7>, wherein the biodegradable resin is at least one selected from the group consisting of a cellulose resin and a polyester resin.

<9> the biodegradable resin particle according to <8>, wherein the biodegradable resin is a cellulose resin.

<10> the biodegradable resin particle according to <9>, wherein the cellulose resin is a cellulose acylate having two or more kinds of acyl groups.

<11> the biodegradable resin particle according to <9> or <10>, wherein the mother particle contains at least one of an aromatic compound having no functional group reactive with the cellulose resin, having a long-chain aliphatic group, and having at least one of a phenolic hydroxyl group and/or a monoglycidyl ether group directly bonded to an aromatic group, and a fatty acid ester.

<12> the biodegradable resin particle according to <11>, wherein the aromatic compound is a cardanol compound.

<13> the biodegradable resin particle according to <12>, wherein the cardanol compound 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 (CDN 1-e).

[ solution 1]

(general formula (CDN1) wherein R¹Represents an alkyl group with or without a substituent, or an unsaturated aliphatic group with or without a substituent and having a double bond. R²Represents a hydroxyl group, a carboxyl group, an alkyl group with or without a substituent, or an unsaturated aliphatic group with or without a substituent and a double bond. P2 represents an integer of 0 to 4. When P2 is 2 or more, plural Rs²The groups may be the same or different. )

[ solution 2]

(in the general formula (CDN1-e), L_EPRepresents a single bond or a 2-valent linking group. In the general formula (CDN1-e), R¹、R²And P2 with R in formula (CDN1), respectively¹、R²And P2. )

<14> the biodegradable resin particle according to any one of <11> to <13>, wherein the mother particle contains cellulose acetate propionate as the cellulose resin and a cardanol compound as the aromatic compound.

<15> the biodegradable resin particle according to any one of <11> to <13>, wherein the mother particle contains cellulose acetate butyrate and the fatty acid ester as the cellulose resin.

<16> the biodegradable resin particle according to any one of <1> to <15>, wherein a mass ratio of a content of the cationic resin in the first layer to a content of the hydrophobic compound in the second layer is 0.1 to 10.

<17> the biodegradable resin particle according to <16>, wherein a content of the cationic resin in the mother particle is 0.1 mass% or more and 10 mass% or less.

<18> the biodegradable resin particle according to any one of <1> to <17>, wherein the cationic resin has a number average molecular weight of 10000 to 85000.

<19> a biodegradable resin particle, which comprises:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

the water contact angle of pellets obtained by pelletizing biodegradable resin particles is 70 DEG to 120 deg.

<20> a biodegradable resin particle, which comprises:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

the aerobic biodegradation rate after 3 months as determined by a method according to ISO-14855-2 (2018) is 20% or less.

<21> a biodegradable resin particle, which comprises:

mother particle comprising biodegradable resin, and

a compound layer present on the surface of the above-mentioned mother particle,

when the surface of the biodegradable resin particle is measured by X-ray photoelectron spectroscopy, the relationship among the carbon atomic weight Cs, the silicon atomic weight Sis and the oxygen atomic weight Os satisfies the formula A: (Cs + Sis)/Os ≧ 3.

<22> the biodegradable resin particle as stated in <21>, wherein a relationship among a carbon atomic weight Ce, a silicon atomic weight Sie and an oxygen atomic weight Oe satisfies the formula B: (Ce + Sie)/Oe ≧ 3.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the aspect of <1>, <2>, <3>, <4>, <5>, <6>, <7> or <8>, there is provided a biodegradable resin particle having a temporal biodegradation rate and a slow initial biodegradation rate, as compared with a biodegradable resin particle having only a layer containing at least one cationic resin of polyalkyleneimine (polyethyleneimine), polyallylamine (polyallylamine) and polyvinylamine (polyvinylamine) on the surface of a mother particle containing a biodegradable resin.

According to the aspect <9>, there is provided biodegradable resin particles having a temporal biodegradation rate and a low initial biodegradation rate as compared with a case where the biodegradable resin is a polyester resin.

According to the aspect <10>, there is provided a biodegradable resin particle having a temporal biodegradation rate and a low initial biodegradation rate as compared with the case where the cellulose resin is a cellulose acylate having one kind of acyl group.

According to the aspect of <11>, there is provided a biodegradable resin particle having biodegradability and excellent hydrolysis resistance, even when a cellulose resin is contained as a biodegradable resin and at least one of an aromatic compound and a fatty acid ester is also contained, as compared with a biodegradable resin particle having only a layer containing at least one cationic resin of polyalkyleneimine, polyallylamine, and polyvinylamine on the surface of a mother particle containing a biodegradable resin.

According to the aspect <12> or <13>, there is provided a biodegradable resin particle having biodegradability and excellent hydrolysis resistance, as compared with a case where an alkyl-modified novolac epoxy resin is used as an aromatic compound.

According to the aspect of <14> or <15>, there is provided a biodegradable resin particle having biodegradability and excellent hydrolysis resistance, as compared with a case where a cellulose acetate-butyrate compound as a cellulose resin and a cardanol compound as an aromatic compound are contained in a mother particle, or a case where a cellulose acetate-propionate compound as a cellulose resin and a fatty acid ester are contained in a mother particle.

According to the aspect <16>, there is provided biodegradable resin particles having a temporal biodegradation rate and a slow initial biodegradation rate as compared with the case where the mass ratio of the cationic resin to the hydrophobic compound is less than 0.1 or more than 10.

According to the aspect <17>, there is provided biodegradable resin particles having a temporal biodegradation rate and a low initial biodegradation rate, as compared with the case where the content of the cationic resin relative to the parent particles is less than 0.1% by mass or more than 10% by mass.

According to the aspect <18>, there is provided biodegradable resin particles having a temporal biodegradation rate and a low initial biodegradation rate as compared with the case where the number average molecular weight of the cationic resin is less than 10000 or more than 85000.

According to the aspect <19>, there is provided a biodegradable resin particle having a temporal biodegradation rate and a low initial biodegradation rate as compared with a biodegradable resin particle having a compound layer on the surface of a mother particle comprising a biodegradable resin and having a water contact angle of a pellet obtained by granulating the biodegradable resin particle of less than 70 °.

According to the aspect <20>, there is provided a biodegradable resin pellet having a temporal biodegradation rate and a low initial biodegradation rate as compared with a biodegradable resin pellet having a compound layer on the surface of a mother pellet containing a biodegradable resin and a biodegradation rate of more than 20% under aerobic conditions after 3 months measured by a method according to ISO-14855-2 (2018).

According to the aspect <21>, there is provided a biodegradable resin particle having a compound layer on a surface of a mother particle containing a biodegradable resin and not satisfying the formula a: the biodegradable resin particles according to this embodiment have a biodegradation rate with time and a low initial biodegradation rate, as compared with the biodegradable resin particles of (Cs + Sis)/Os ≧ 3.

According to the aspect <22>, there is provided a biodegradable resin particle having a compound layer on a surface of a mother particle containing a biodegradable resin, but not satisfying the formula B: the biodegradable resin particles according to this embodiment have a lower initial biodegradation rate and a higher biodegradation rate with time than the biodegradable resin particles according to (Ce + Sie)/Oe ≧ 3.

Detailed Description

The following describes an embodiment as an example of the present invention. The description and examples are intended to illustrate embodiments and are not intended to limit the scope of the embodiments.

In the numerical ranges recited in the present specification in stages, the upper limit or the lower limit recited in one numerical range may be replaced with the upper limit or the lower limit recited in another numerical range in another stage. In addition, in the numerical ranges described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.

In the present specification, the term "step" includes not only an independent step but also a step that can achieve a desired purpose of the step even when the step cannot be clearly distinguished from other steps.

Each component may comprise two or more corresponding substances.

In the case where the amount of each component is mentioned, in the case where two or more substances corresponding to each component are present, the total amount of the two or more substances is referred to unless otherwise specified.

"(meth) acrylic acid" means at least one of acrylic acid and methacrylic acid, and "(meth) acrylate" means at least one of acrylate and methacrylate.

< biodegradable resin particles >

First embodiment

The biodegradable resin particle of the first embodiment has: a mother particle containing a biodegradable resin; a first layer containing at least one cationic resin of polyalkyleneimine, polyallylamine, and polyvinylamine present on the surface of the mother particle; and a second layer comprising an anionic or nonionic hydrophobic compound present on the first layer.

With the above configuration, the biodegradable resin particles according to the first embodiment can be produced as biodegradable resin particles having a biodegradation rate with time (for example, 12 months under aerobic conditions) and a biodegradation rate at an initial stage (for example, 3 months under aerobic conditions) that is slow. The reason for this is presumed as follows.

A rapid biodegradation rate is required for biodegradable resin particles. However, if the biodegradation rate is too high, the durability of the resin particles themselves is rapidly reduced. That is, it is required to maintain the function as resin particles for a certain period (for example, for a period of several years during use).

Therefore, a second layer containing an anionic or nonionic hydrophobic compound is provided on the surface of the mother particle containing a biodegradable resin, with a first layer containing at least one cationic resin selected from the group consisting of polyalkyleneimine, polyallylamine, and polyvinylamine interposed therebetween.

The presence of the first layer containing the cationic resin causes the anionic or nonionic hydrophobic compound to be adsorbed onto the surface of the mother particle to form a hydrophobic second layer, thereby increasing the surface hydrophobicity of the biodegradable resin particle. This slows down the initial biodegradation rate, and the resin particles can maintain their functions for a certain period of time. Since biodegradation of the hydrophobic biochemical compound in the second layer proceeds with time, biodegradability of the mother particle itself including the biodegradable resin is exerted over time.

Therefore, it is presumed that the biodegradable resin particles according to the first embodiment have a temporal biodegradation rate and a low initial biodegradation rate.

Second embodiment

The biodegradable resin particle according to the second embodiment has a parent particle containing a biodegradable resin and a compound layer present on the surface of the parent particle, and the water contact angle of a pellet obtained by granulating the biodegradable resin particle is 70 ° to 120 °.

With the above configuration, the biodegradable resin particles according to the second embodiment can be produced as biodegradable resin particles having a biodegradation rate with time (for example, 12 months under aerobic conditions) and a biodegradation rate at an initial stage (for example, 3 months under aerobic conditions) that is slow.

The reason for this is that, within the range of the contact angle, the surface of the compound layer in the biodegradable resin particle exhibits hydrophobicity, and the hydrolyzability of the biodegradable resin of the parent particle can be suppressed, whereby the initial biodegradation rate is lowered, and the function as the resin particle is maintained for a certain period of time. Further, since the decomposition of the component of the compound layer of the biodegradable resin particle continues over a certain period of time, the biodegradability of the mother particle itself containing the biodegradable resin is exerted over time.

Third embodiment

The biodegradable resin pellet according to the third embodiment has a mother pellet containing a biodegradable resin and a compound layer present on the surface of the mother pellet, and has a biodegradation rate of 20% or less under aerobic conditions after 3 months as measured by a method according to ISO-14855-2 (2018).

The biodegradable resin particle according to the third embodiment having the above-described configuration can be produced as a biodegradable resin particle having a biodegradation rate with time (for example, 12 months under aerobic conditions) and a biodegradation rate at an initial stage (for example, 3 months under aerobic conditions).

The reason for this is that the compound layer in the biodegradable resin pellet reduces the biodegradation rate under aerobic conditions after the above-mentioned 3 months, and the hydrolyzability of the biodegradable resin of the mother pellet is suppressed, whereby the initial biodegradation rate is lowered, and the function as the resin pellet is maintained for a certain period of time. Further, since the decomposition of the component of the compound layer of the biodegradable resin particle continues over a certain period of time, the biodegradability of the mother particle itself containing the biodegradable resin is exerted over time.

Fourth embodiment

The biodegradable resin pellet of the fourth embodiment has a mother pellet containing a biodegradable resin and a compound layer present on the surface of the mother pellet, and when the surface of the biodegradable resin pellet is measured by X-ray photoelectron spectroscopy (XPS), the relationship of the carbon atomic weight Cs, the silicon atomic weight Sis, and the oxygen atomic weight Os satisfies the formula a: (Cs + Sis)/Os ≧ 3.

With the above configuration, the biodegradable resin particles according to the fourth embodiment can be produced as biodegradable resin particles having a biodegradation rate with time (for example, 12 months under aerobic conditions) and a biodegradation rate at an initial stage (for example, 3 months under aerobic conditions) that is slow.

The reason for this is that the compound layer in the biodegradable resin particle increases the amount of carbon atoms and silicon atoms present on the surface of the biodegradable resin particle so as to satisfy formula a, thereby increasing the hydrophobicity of the surface of the biodegradable resin particle and suppressing the hydrolyzability of the biodegradable resin of the parent particle, thereby slowing down the initial biodegradation rate and maintaining the function as the resin particle for a certain period of time. Further, since the decomposition of the component of the compound layer of the biodegradable resin particle continues over a certain period of time, the biodegradability of the mother particle itself containing the biodegradable resin is exerted over time.

Further, by increasing the amount of carbon atoms and silicon atoms present on the surface of the particles, the lipophilicity of the surface of the biodegradable resin particles is increased, and the oil absorption of the resin particles is increased.

The conventional biodegradable resin particles are excellent in degradability under natural environment, while having a relatively hydrophilic structure, and therefore have low compatibility with oil or low oil absorption. For example, when conventional biodegradable resin particles are added to cosmetics or the like, if the oil absorption is low, makeup removal tends to occur due to sebum or the like. In addition, when conventional biodegradable resin particles are added to a coating material, the particles may aggregate into lumps if they have low oil absorption and poor compatibility with oil. Therefore, the biodegradable resin particles having a high oil absorption rate are not likely to cause removal of makeup even when added to a cosmetic, and are not likely to aggregate even when added to a paint, and are useful in the fields of cosmetics, paints, and the like.

Here, in the biodegradable resin particles according to the second to fourth embodiments, examples of the compound layer include: a two-layer compound layer comprising a first layer containing at least one cationic resin of polyalkyleneimine, polyallylamine, and polyvinylamine, and a second layer containing an anionic or nonionic hydrophobic compound present on the first layer.

In the biodegradable resin particles according to the second and third embodiments, for example, the compound layer is not particularly limited as long as the compound layer is provided with the above-described characteristics of the biodegradable resin particles according to the second and third embodiments.

The biodegradable resin particles (hereinafter, also referred to as "biodegradable resin particles of the present embodiment") that are the biodegradable resin particles according to any one of the first to fourth embodiments will be described in detail. However, an example of the biodegradable resin particle of the present invention may be a biodegradable resin particle that corresponds to any one of the biodegradable resin particles of the first to fourth embodiments.

The biodegradable resin particles according to the present embodiment will be described in detail below.

[ mother particle ]

The mother particle is a target particle forming the first layer and the second layer, and includes a biodegradable resin.

The mother particle includes particles containing a biodegradable resin as a main component, and specifically includes particles containing a biodegradable resin in an amount of preferably 90 mass%, more preferably 95 mass%, still more preferably 98 mass%, and particularly preferably 100 mass% with respect to the whole of the mother particle.

Biodegradable resins

The biodegradable resin is a resin that is decomposed into water and carbon dioxide by the action of microorganisms. Specifically, the biodegradable resin is a resin having a biodegradability of 50% or more in 1 month as measured by a method according to ISO-14855-2 (2018).

Examples of the biodegradable resin include polyester resins, natural polymers, and polyvinyl alcohols.

Examples of the polyester resin include aliphatic polyester resins and aliphatic aromatic polyester resins.

Examples of the aliphatic polyester resin include polylactic acid (PLA); polyglycolic acid (PGA); polyhydroxyalkanoic acids such as polyhydroxybutyrate, poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polycaprolactone, polybutylene succinate (PBS), polybutylene succinate/adipate (PBSA), and polyethylene succinate (PBA); and so on.

Examples of the aliphatic aromatic polyester resin include polybutylene adipate/terephthalate copolymer resin (PBAH), polytetramethylene adipate/terephthalate copolymer resin, and the like.

Examples of the natural polymer include starch, cellulose, chitin, chitosan, gluten, gelatin, zein, soybean protein, collagen, keratin, and the like.

Among these, as the biodegradable resin, at least one selected from the group consisting of cellulose resins and polyester resins is preferable, and cellulose resins are more preferable, from the viewpoint of increasing the rate of temporal biodegradation.

As the cellulose resin, cellulose acylate is preferable. Cellulose acylate is a cellulose derivative in which at least a part of hydroxyl groups in cellulose is substituted with acyl groups (in other words, acylation is performed). Acyl is of the formula-CO-R^AC(R^ACRepresents a hydrogen atom or a hydrocarbon group).

The cellulose acylate is, for example, a cellulose derivative represented by the following general formula (CA).

[ solution 1]

In the general formula (CA), A¹、A²And A³Each independently represents a hydrogen atom or an acyl group, and n represents an integer of 2 or more. Wherein n is A¹N number of A²And n is A³At least a part of (a) represents an acyl group. N number of A in molecule¹May be all the same, may be partially the same, or may be different from each other. Likewise, n A's in the molecule²And n is A³Or may be the same or partially the same or different from each other。

A¹、A²And A³In the acyl group, the hydrocarbon group in the acyl group may be linear, branched or cyclic, preferably linear or branched, more preferably linear.

A¹、A²And A³In the acyl group, the hydrocarbon group in the acyl group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, and is preferably a saturated hydrocarbon group.

A¹、A²And A³Among the acyl groups, preferred is an acyl group having 1 to 6 carbon atoms. That is, as the cellulose acylate, a cellulose acylate having an acyl group with 1 to 6 carbon atoms is preferable.

A¹、A²And A³The acyl group represented 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, and is preferably unsubstituted.

As A¹、A²And A³Examples of the acyl group include formyl, acetyl, propionyl, butyryl, acryloyl, and hexanoyl. Among these, the acyl group is preferably an acyl group having 2 to 4 carbon atoms, and more preferably an acyl group having 2 or 3 carbon atoms, because the rate of biodegradation of the resin particles is increased.

Examples of the cellulose acylate include cellulose acetate (e.g., cellulose monoacetate, cellulose Diacetate (DAC), cellulose triacetate), Cellulose Acetate Propionate (CAP), and Cellulose Acetate Butyrate (CAB).

The cellulose acylate is preferably a cellulose acylate having two or more acyl groups, from the viewpoint of increasing the biodegradation rate of the resin particles. Specifically, as the cellulose acylate, Cellulose Acetate Propionate (CAP) and Cellulose Acetate Butyrate (CAB) are preferable, and Cellulose Acetate Propionate (CAP) is more preferable, from the viewpoint of increasing the biodegradation rate of the resin particles.

The cellulose acylate may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The weight-average degree of polymerization of the cellulose acylate is preferably 200 to 1000, more preferably 500 to 1000, and still more preferably 600 to 1000.

The weight-average polymerization degree of cellulose acylate is determined from the weight-average molecular weight (Mw) in the following order.

First, the weight average molecular weight (Mw) of the cellulose acylate was measured in terms of polystyrene using a gel permeation chromatography apparatus (GPC apparatus: manufactured by Tosoh corporation, HLC-8320GPC, column: TSKgel. alpha. -M) using tetrahydrofuran.

Next, the polymerization degree of the cellulose acylate is determined by dividing the weight average molecular weight (Mw) of the cellulose acylate by the molecular weight of the structural unit of the cellulose acylate. For example, in the case where the substituent of the cellulose acylate is an acetyl group, the molecular weight of the structural unit is 263 when the substitution degree is 2.4 and 284 when the substitution degree is 2.9.

From the viewpoint of increasing the biodegradation rate of the resin particles, the degree of substitution of the cellulose acylate is preferably 2.1 to 2.9, more preferably 2.2 to 2.9, still more preferably 2.3 to 2.9, and particularly preferably 2.6 to 2.9.

In Cellulose Acetate Propionate (CAP), the ratio of the substitution degree of acetyl group to propionyl group (acetyl group/propionyl group) is preferably 0.01 to 1, more preferably 0.05 to 0.1, from the viewpoint of increasing the biodegradation rate of the resin particles.

In Cellulose Acetate Butyrate (CAB), the ratio of the degrees of substitution of acetyl groups and butyryl groups (acetyl/butyryl groups) is preferably 0.05 to 3.5, more preferably 0.5 to 3.0, from the viewpoint of increasing the rate of biodegradation of the resin particles.

The degree of substitution of cellulose acylate is an index indicating the degree of substitution of the hydroxyl group of cellulose with an acyl group. That is, the degree of substitution is an index indicating the degree of acylation of cellulose acylate. Specifically, the substitution degree is an intramolecular average of the number of substitutions by an acyl group in 3 hydroxyl groups on the D-glucopyranose unit of the cellulose acylate. Degree of substitution utilization¹H-NMR (JMN-ECA/JEOL RESONANCE Co., Ltd.)Production) was determined from the integral ratio of the peaks of hydrogen derived from cellulose and hydrogen derived from acyl groups.

These biodegradable resins may be used alone in 1 kind, or in 2 or more kinds.

Other ingredients-

Other ingredients may be included in the parent particle.

Examples of the other components include plasticizers, flame retardants, compatibilizers, mold release agents, light stabilizers, weather stabilizers, colorants, pigments, modifiers, anti-dripping agents, antistatic agents, hydrolysis stabilizers, fillers, reinforcing agents (glass fibers, carbon fibers, talc, clay, mica, glass flakes, ground glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.), acid acceptors for preventing acetic acid release (oxides such as magnesium oxide and aluminum oxide, metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide, hydrotalcite, etc.), calcium carbonate, talc, etc.), reactive trapping agents (for example, epoxy compounds, acid anhydride compounds, carbodiimide, etc.), and the like.

The content of the other components is preferably 0 mass% or more and 5 mass% or less, respectively, with respect to the total amount of the mother granules. Here, "0 mass%" means that the mother particle contains no other component.

Examples of the plasticizer include ester compounds, camphor, metal soaps, polyols, polyalkylene oxides, and the like. As the plasticizer, an ester compound is preferable in terms of improving the mechanical properties of the resin particles. The plasticizer may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Examples of the ester compound include fatty acid esters (e.g., adipic acid esters, citric acid esters, sebacic acid esters, azelaic acid esters, phthalic acid esters, and acetic acid esters), phosphoric acid esters, condensed phosphoric acid esters, ethylene glycol esters (e.g., ethylene benzoate), and modified fatty acid esters (e.g., epoxidized fatty acid esters). Examples of the ester include monoesters, diesters, triesters, and polyesters. Among them, dicarboxylic acid diesters (adipic acid diester, sebacic acid diester, azelaic acid diester, phthalic acid diester, etc.) are preferable.

As the plasticizer, adipic acid ester is preferable. Adipic acid ester has high affinity with cellulose acylate and is dispersed in the cellulose acylate in a nearly uniform state, whereby thermal fluidity can be further improved as compared with other plasticizers.

As the adipate ester, a mixture of the adipate ester and other components may be used. Examples of commercially available products of the mixture include daicatty 101 manufactured by Daihuachikushi chemical industry.

Examples of the fatty acid ester such as citrate, sebacate, azelate, phthalate, and acetate include esters of fatty acids and alcohols. Examples of the alcohol include monohydric alcohols such as methanol, ethanol, propanol, butanol, and 2-ethylhexanol; polyhydric alcohols such as glycerin, polyglycerin (e.g., diglycerin), pentaerythritol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, trimethylolethane, and sugar alcohols; and so on.

Examples of the glycol in the ethylene benzoate include ethylene glycol, diethylene glycol, and propylene glycol.

The epoxidized fatty acid ester is an ester compound having a structure in which a carbon-carbon unsaturated bond of an unsaturated fatty acid ester is epoxidized (i.e., oxetane). Examples of the epoxidized fatty acid ester include esters of fatty acids and alcohols in which a part or all of carbon-carbon unsaturated bonds in unsaturated fatty acids (for example, oleic acid, palmitoleic acid, vaccenic acid, linoleic acid, linolenic acid, nervonic acid, and the like) are epoxidized. Examples of the alcohol include monohydric alcohols such as methanol, ethanol, propanol, butanol, and 2-ethylhexanol; polyhydric alcohols such as glycerin, polyglycerin (e.g., diglycerin), pentaerythritol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, trimethylolpropane, trimethylolethane, and sugar alcohols; and so on.

The molecular weight (or weight average molecular weight) of the ester compound as the plasticizer is preferably 200 to 2000, more preferably 250 to 1500, and further preferably 280 to 1000. Unless otherwise specified, the weight average molecular weight of the ester compound is a value determined in accordance with the method for determining the weight average molecular weight of the cellulose acylate.

Here, when a cellulose resin is used as the biodegradable resin, it is particularly preferable that the mother particle contains the cellulose resin and at least one of an aromatic compound (hereinafter also referred to as "aromatic compound (B1)") and a fatty acid ester (hereinafter also referred to as "fatty acid ester (B2)") as a plasticizer, the aromatic compound (B1) having no functional group that reacts with the cellulose resin and having at least one of a long-chain aliphatic group, a phenolic hydroxyl group, and a monoglycidyl ether group directly bonded to the aromatic group.

The cellulose resin is not easily hydrolyzed when it is a single substance, but is difficult to mold due to poor flexibility, and it is preferable to add a plasticizer to the cellulose resin in order to impart flexibility. However, cellulose resins with plasticizers added thereto are susceptible to hydrolysis. Therefore, coating the second layer containing the hydrophobic compound on the mother particle containing the cellulose resin and the plasticizer is effective for securing biodegradability while imparting hydrolysis resistance.

On the other hand, in order to slow down the initial biodegradation rate, it is preferable that the second layer comprising the hydrophobic compound is firmly coated on the mother particle.

In this regard, when at least one of an aromatic compound (B1) and a fatty acid ester (B2) is used as the plasticizer contained in the mother particle, the first layer containing the cationic resin more firmly covers the surface of the mother particle, and functions as an adhesive layer between the surface of the mother particle and the second layer containing the hydrophobic compound. As a result, the second layer containing the hydrophobic compound is more firmly coated on the mother particle, and high hydrolysis resistance can be imparted to the biodegradable resin particle while ensuring biodegradability. The reason for this is presumed as follows.

Since the aromatic compound (B1) has a benzene ring, the benzene ring attracts electrons, and OH groups are biased to be acidic. Therefore, the reactivity with the cationic compound is high. Further, the fatty acid ester (B2) is a compound which is slightly acidic, and therefore has high reactivity with a cationic compound. As a result, the first layer containing the cationic resin more firmly covers the surface of the mother particle.

Therefore, it is presumed that the second layer containing the hydrophobic compound is more firmly coated on the mother particle, and can impart high hydrolysis resistance to the biodegradable resin particle while ensuring biodegradability. As a result, biodegradable resin pellets having excellent hydrolysis resistance while maintaining biodegradability were obtained.

In particular, when cellulose acetate propionate is used as a cellulose resin from the viewpoint of improving hydrolysis resistance while maintaining biodegradability, it is preferable to use a cardanol compound as an aromatic compound as a plasticizer.

In the same way, when cellulose acetate propionate is used as the cellulose resin, an aliphatic ester is preferably used as the plasticizer.

The aromatic compound (B1) will be explained below.

The aromatic compound (B1) is an aromatic compound having no functional group that reacts with the cellulose resin, has a long-chain aliphatic group, and has at least one of a phenolic hydroxyl group and a monoglycidyl ether group directly bonded to the aromatic group.

That is, the aromatic compound (B1) is a compound having no functional group that reacts with the cellulose acylate, having a long-chain aliphatic group, and having at least one of a phenolic hydroxyl group and a monoglycidyl ether group.

Examples of the long-chain aliphatic group include a saturated aliphatic group (i.e., an alkyl group) having 6 to 30 carbon atoms (preferably 10 to 20 carbon atoms) and an unsaturated aliphatic group (i.e., an alkenyl group or an alkynyl group) having 6 to 30 carbon atoms (preferably 10 to 20 carbon atoms). The aliphatic group may be linear, branched or cyclic, and is preferably linear or branched, more preferably linear.

Examples of the aromatic compound (B1) include compounds in which a long-chain aliphatic group is substituted with a single ring, a condensed ring (a polycyclic ring having 2 or more aromatic rings), a polycyclic ring (a polycyclic ring in which aromatic rings are bonded to each other via a carbon-carbon bond), a heterocyclic ring (a monocyclic heterocyclic ring, a condensed ring containing a heterocyclic ring, a polycyclic ring containing a heterocyclic ring, or the like), and a phenolic hydroxyl group is substituted with the heterocyclic ring.

Specific examples of the aromatic compound (B1) include cardanol compounds, phenol-aldehyde amine compounds, phenol resins, novolac-type epoxy resins, resol-type epoxy resins, phenol-modified palm oil, phenol-modified soybean oil, and phenol-modified linseed oil.

Among these, cardanol compound is preferable as the aromatic compound (B1) in terms of improving biodegradability.

The cardanol compound is a component (for example, a compound represented by the following structural formulae (b-1) to (b-4)) contained in a compound derived from a natural source using a cardanol as a raw material, or a derivative derived from the component.

[ solution 2]

The cardanol compound may also be a mixture of compounds derived from natural sources using cashews as a raw material (hereinafter also referred to as "cashew-derived mixture").

The cardanol compound may also be a derivative derived from a mixture of cashew sources. Examples of the derivative derived from the mixture derived from cashew nut include the following mixtures and single substances.

A mixture obtained by adjusting the composition ratio of each component in the cashew nut-derived mixture

A single substance obtained by separating only a specific component from a mixture derived from cashew nuts

Mixture containing modified product obtained by modifying component in cashew nut-derived mixture

Mixture containing polymer obtained by polymerizing components in cashew nut-derived mixture

A mixture containing a modified polymer obtained by modifying and polymerizing components in the cashew nut-derived mixture

A mixture containing a modified product obtained by further modifying the components in the mixture having the above-mentioned composition ratio adjusted

A mixture containing a polymer obtained by further polymerizing the components in the mixture having the above-mentioned composition ratio adjusted

A mixture containing a modified polymer obtained by modifying and polymerizing the components of the mixture having the above-mentioned composition ratio adjusted

A modified product obtained by further modifying the separated single substance

A polymer obtained by further polymerizing the separated single substance

A modified polymer obtained by further modifying and polymerizing the separated single substance

The single substance herein also includes multimers such as dimers and trimers.

The cardanol compound is preferably at least one compound selected from the group consisting of a compound represented by general formula (CDN1) and a polymer obtained by polymerizing a compound represented by general formula (CDN1), from the viewpoint of increasing the biodegradation rate of the resin particles.

[ solution 3]

In the general formula (CDN1), R¹Represents an alkyl group with or without a substituent, or an unsaturated aliphatic group with or without a substituent and having a double bond. R²Represents a hydroxyl group, a carboxyl group, an alkyl group with or without a substituent, or an unsaturated aliphatic group with or without a substituent and a double bond. P2 represents an integer of 0 to 4. When P2 is 2 or more, plural Rs²The groups may be the same or different.

In the general formula (CDN1), R¹The alkyl group having a substituent(s) is preferably an alkyl group having 3 to 30 carbon atoms, more preferably an alkyl group having 5 to 25 carbon atoms, and still more preferably an alkyl group having 8 to 20 carbon atoms.

Examples of the substituent include: a hydroxyl group; an ether bond-containing substituent such as an epoxy group or a methoxy group; substituents containing ester bonds such as acetyl and propionyl; and so on.

Examples of the alkyl group which may have a substituent include pentadecan-1-yl, heptane-1-yl, octane-1-yl, nonane-1-yl, decane-1-yl, undecane-1-yl, dodecane-1-yl, tetradecane-1-yl, and the like.

In the general formula (CDN1), R¹The unsaturated aliphatic group having a double bond and having or not having 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 still more preferably an unsaturated aliphatic group having 8 to 20 carbon atoms.

The number of double bonds of the unsaturated aliphatic group is preferably 1 to 3.

Examples of the substituent include those listed as substituents for the above-mentioned alkyl groups.

Examples of the unsaturated aliphatic group having a double bond and having or not having a substituent include pentadec-8-en-1-yl, pentadec-8, 11-dien-1-yl, pentadec-8, 11, 14-trien-1-yl, pentadec-7-en-1-yl, pentadec-7, 10-dien-1-yl, pentadec-7, 10, 14-trien-1-yl, and the like.

In the general formula (CDN1), as R¹Pentadec-8-en-1-yl, pentadec-8, 11-dien-1-yl, pentadec-8, 11, 14-trien-1-yl, pentadec-7-en-1-yl, pentadec-7, 10-dien-1-yl, pentadec-7, 10, 14-trien-1-yl are preferred.

In the general formula (CDN1), as R²The above-mentioned R is the same as the above-mentioned alkyl group having a substituent or not and the unsaturated aliphatic group having a double bond and having a substituent or not¹The preferable examples include alkyl groups having or not having a substituent and unsaturated aliphatic groups having a double bond and having or not having a substituent.

The compound represented by the general formula (CDN1) may be further modified. For example, the epoxy group may be performed, and in order to increase the biodegradation rate of the resin particles, specifically, a compound having a structure in which a hydroxyl group of 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), is preferable.

[ solution 4]

In the group (EP) and the general formula (CDN1-e), L_EPRepresents a single bond or a 2-valent linking group. In the general formula (CDN1-e), R¹、R²And P2 with R in formula (CDN1), respectively¹、R²And P2.

In the group (EP) and the general formula (CDN1-e), as L_EPExamples of the 2-valent linking group include an alkylene group (preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 1 carbon atom) having or not having a substituent, and-CH₂CH₂OCH₂CH₂-radicals and the like.

Examples of the substituent include R in the general formula (CDN1)¹The substituents in (1) above are exemplified.

As L_EPMethylene is preferred.

The polymer obtained by polymerizing the compound represented by the general formula (CDN1) means a polymer obtained by polymerizing at least 2 compounds represented by the general formula (CDN1) with or without a linking group.

Examples of the polymer obtained by polymerizing the compound represented by the general formula (CDN1) include a compound represented by the following general formula (CDN 2).

[ solution 5]

In the general formula (CDN2), R¹¹、R¹²And R¹³Each independently represents an alkyl group with or without a substituent, orAn unsaturated aliphatic group having a double bond and having or not having a substituent. R²¹、R²²And R²³Each independently represents a hydroxyl group, a carboxyl group, an alkyl group with or without a substituent, or an unsaturated aliphatic group with or without a substituent and having a double bond. P21 and P23 each independently represent an integer of 0 to 3, and P22 represents an integer of 0 to 2. L is¹And L²Each independently represents a 2-valent linking group. n represents an integer of 0 to 10 inclusive. When P21 is 2 or more, plural R's are present²¹When P22 is 2 or more, a plurality of R exist²²And when P23 is 2 or more, a plurality of R exist²³The groups may be the same or different. When n is 2 or more, a plurality of R exist¹²、R²²And L¹Each of P22 may be the same or different, and when n is 2 or more, the number of P22 present may be the same or different.

In the general formula (CDN2), as R¹¹、R¹²、R¹³、R²¹、R²²And R²³Examples of the substituted or unsubstituted alkyl group and the double-bonded substituted or unsubstituted unsaturated aliphatic group include R of the general formula (CDN1)¹And the groups listed are preferred examples.

In the general formula (CDN2), as L¹And L²Examples of the 2-valent linking group include an alkylene group (preferably an alkylene group having 2 to 30 carbon atoms, more preferably an alkylene group having 5 to 20 carbon atoms) which may have a substituent, and the like.

Examples of the substituent include R in the general formula (CDN1)¹The substituents in (1) above are exemplified.

In the general formula (CDN2), n is preferably 1 to 10, more preferably 1 to 5.

The compound represented by the general formula (CDN2) may be further modified. For example, epoxidation may be carried out, specifically, a compound having a structure in which a hydroxyl group of a compound represented by the general formula (CDN2) is replaced with a group (EP), that is, a compound represented by the following general formula (CDN 2-e).

[ solution 6]

In the general formula (CDN2-e), R¹¹、R¹²、R¹³、R²¹、R²²、R²³、P21、P22、P23、L¹、L²And n is independently from R in formula (CDN2)¹¹、R¹²、R¹³、R²¹、R²²、R²³、P21、P22、P23、L¹、L²And n have the same meaning.

In the general formula (CDN2-e), L_EP1、L_EP2And L_EP3Each independently represents a single bond or a 2-valent linking group. When n is 2 or more, a plurality of L exist_EP2The groups may be the same or different.

In the general formula (CDN2-e), as L_EP1、L_EP2And L_EP3The 2-valent linking group represented by the general formula (CDN1-e) can be similarly mentioned as L_EPThe 2-valent linking group shown is a preferred example.

The polymer obtained by polymerizing the compound represented by the general formula (CDN1) may be, for example, a polymer obtained by three-dimensionally crosslinking and polymerizing at least 3 compounds represented by the general formula (CDN1) with or without a linking group. Examples of the polymer obtained by three-dimensional crosslinking polymerization of the compound represented by the general formula (CDN1) include compounds represented by the following structural formulae.

[ solution 7]

In the above structural formula, R¹⁰、R²⁰And P20 with R in formula (CDN1), respectively¹、R²And P2. L is¹⁰Represents a single bond or a 2-valent linking group. There are a plurality of R¹⁰、R²⁰And L¹⁰The groups may be the same or different. The P20 s present in plural numbers may be the same number or different numbers.

In the above structural formula, as L¹⁰Examples of the 2-valent linking group include an alkylene group (preferably an alkylene group having 2 to 30 carbon atoms, more preferably an alkylene group having 5 to 20 carbon atoms) which may have a substituent, and the like.

Examples of the substituent include R in the general formula (CDN1)¹The substituents in (1) above are exemplified.

The compound represented by the above structural formula may be further modified, for example, may be epoxidized. Specifically, the compound may have a structure in which a hydroxyl group of the compound represented by the above structural formula is replaced with a group (EP), and examples thereof include a polymer obtained by three-dimensionally crosslinking and polymerizing a compound represented by the following structural formula, i.e., a compound represented by the general formula (CDN 1-e).

[ solution 8]

In the above structural formula, R¹⁰、R²⁰And P20 with R in the general formula (CDN1-e), respectively¹、R²And P2. L is¹⁰Represents a single bond or a 2-valent linking group. There are a plurality of R¹⁰、R²⁰And L¹⁰The groups may be the same or different. The P20 s present in plural numbers may be the same number or different numbers.

In the above structural formula, as L¹⁰Examples of the 2-valent linking group include an alkylene group (preferably an alkylene group having 2 to 30 carbon atoms, more preferably an alkylene group having 5 to 20 carbon atoms) which may have a substituent, and the like.

As mentioned aboveThe substituents may be similarly R in the general formula (CDN1)¹The substituents in (1) above are exemplified.

The cardanol compound preferably contains a cardanol compound having an epoxy group, and more preferably a cardanol compound having an epoxy group, from the viewpoint of improving the transparency of the resin molded body.

As the cardanol compound, a commercially available product can 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, NX-9203, LB-7000, LB-7250 and CD-5L, which are available from Cardolite corporation. Examples of commercially available products of epoxy group-containing cardanol compounds include NC-513, NC-514S, NC-547, LITE513E, and Ultra LTE 513 manufactured by Cardolite corporation.

From the viewpoint of increasing the biodegradation rate of the resin molded product, the hydroxyl value of the cardanol compound is preferably 100mgKOH/g or more, more preferably 120mgKOH/g or more, and still more preferably 150mgKOH/g or more. The hydroxyl value of the cardanol compound was measured according to method a of ISO 14900.

When a cardanol compound having an epoxy group is used as the cardanol compound, the epoxy equivalent thereof 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 resin molded body. The epoxy equivalent of the cardanol compound having an epoxy group was measured according to ISO 3001.

From the viewpoint of increasing the biodegradation rate of the resin molded product, the molecular weight of the cardanol compound is preferably 250 to 1000, more preferably 280 to 800, and even more preferably 300 to 500.

The cardanol compound can be used alone in 1 kind, or can be used together in more than 2 kinds.

The fatty acid ester (B2) is explained below.

The fatty acid ester (B2) may be any of a monoester, a diester, a triester, and a polyester.

Examples of the fatty acid ester (B2) include aliphatic monocarboxylic acid esters (e.g., acetic acid esters), aliphatic dicarboxylic acid esters (e.g., succinic acid esters, adipic acid esters, azelaic acid esters, sebacic acid esters, and stearic acid esters), aliphatic tricarboxylic acid esters (e.g., citric acid esters and isocitric acid esters), epoxidized fatty acid esters (e.g., epoxidized soybean oil, epoxidized linseed oil, epoxidized isobutyl rapeseed fatty acid, and epoxidized 2-ethylhexyl fatty acid esters), fatty acid methyl esters, and sucrose esters.

The fatty acid ester can be acylated with an alkylcarboxylic acid anhydride (for example, a linear or branched alkylcarboxylic acid anhydride having 2 to 6 carbon atoms (preferably 2 to 3 carbon atoms) such as acetic anhydride, propionic anhydride, butyric anhydride or valeric anhydride).

The fatty acid ester (B2) may suitably be an aliphatic dicarboxylic acid ester (particularly, an adipate ester or a sebacate ester) or an aliphatic tricarboxylic acid ester (particularly, a citrate ester).

Specific examples of the adipic acid ester include an adipic acid diester represented by the following general formula (AE) and an adipic acid polyester represented by the following general formula (APE).

[ solution 9]

In the general formula (AE), R^AE1And R^AE2Each independently represents an alkyl group or a polyoxyalkyl group [ - (C)_xH_2x-O)_y-R^A1](wherein, R^A1Represents an alkyl group, x represents an integer of 1 to 10, and y represents an integer of 1 to 10).

In the general formula (APE), R^AE1And R^AE2Each independently represents an alkyl group or a polyoxyalkyl group [ - (C)_xH_2x-O)_y-R^A1](wherein, R^A1Represents an alkyl group, x represents an integer of 1 to 10, y represents an integer of 1 to 10), R^AE3Represents an alkylene group. m1 represents an integer of 1 to 10, and m2 represents an integer of 1 to 20 inclusive.

In the general formulae (AE) and (APE), R is^AE1And R^AE2The alkyl group preferably has 1 to 12 carbon atomsMore preferably, an alkyl group having 4 to 10 carbon atoms is used, and still more preferably an alkyl group having 8 carbon atoms is used. R^AE1And R^AE2The alkyl group represented by the above general formula (I) may be linear, branched or cyclic, and is preferably linear or branched.

In the general formulae (AE) and (APE), R is^AE1And R^AE2Polyoxyalkyl [ - (C) of_xH_2x-O)_y-R^A1]R in (1)^A1The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. R^A1The alkyl group represented by the above general formula (I) may be linear, branched or cyclic, and is preferably linear or branched.

In the general formula (APE), as R^AE3The alkylene group is preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms. The alkylene group may be linear, branched or cyclic, and is preferably linear or branched.

In the general formula (APE), m1 is preferably an integer of 1 to 5, and m2 is preferably an integer of 1 to 10.

In the general formulae (AE) and (APE), the groups represented by the symbols may be substituted with a substituent. Examples of the substituent include an alkyl group, an aryl group, and a hydroxyl group.

As the adipate ester, a mixture of adipate ester and other components may be used. Examples of commercially available products of the mixture include daicatty 101 manufactured by Daihuachikushi chemical industry.

Examples of the sebacate include alkyl esters of sebacic acid having 1 to 12 (preferably 1 to 8) carbon atoms.

Examples of the citric acid ester include alkyl esters of citric acid having 1 to 12 (preferably 1 to 8) carbon atoms. The citric acid ester may be one acylated with an alkylcarboxylic acid anhydride (for example, a linear or branched alkylcarboxylic acid anhydride having 2 to 6 carbon atoms (preferably 2 to 3 carbon atoms) such as acetic anhydride, propionic anhydride, butyric anhydride or valeric anhydride).

The molecular weight (or weight average molecular weight) of the fatty acid ester (B2) is preferably 200 to 2000, more preferably 250 to 1500, and still more preferably 280 to 1000. Unless otherwise specified, the weight average molecular weight of the fatty acid ester (B2) is a value determined according to the method for determining the weight average molecular weight of cellulose acylate.

The content of the aromatic compound, the fatty acid ester, or the total of the aromatic compound and the fatty acid ester is preferably 1 mass% to 50 mass%, more preferably 1 mass% to 30 mass%, relative to the cellulose resin.

The mother particle may contain a resin other than the biodegradable resin. When other resin is contained, the content of the other resin may be 5% by mass or less, preferably less than 1% by mass, relative to the total amount of the resin composition. More preferably, the mother particle contains no other resin (i.e., 0 mass%).

Examples of the other resins include conventionally known thermoplastic resins, specifically, polycarbonate resins; a polypropylene resin; a polyester resin; a polyolefin resin; a polyester carbonate resin; a polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; polyether sulfone resin; a polyarylene resin; a polyetherimide resin; a polyacetal resin; a polyvinyl acetal resin; a polyketone resin; a polyetherketone resin; polyether ether ketone resin; a polyaryl ketone resin; a polyether nitrile resin; a liquid crystal resin; a polybenzimidazole resin; a polyoxamide resin; a vinyl polymer or copolymer obtained by polymerizing or copolymerizing 1 or more vinyl monomers selected from the group consisting of aromatic vinyl compounds, methacrylic acid esters, acrylic acid esters, and vinyl cyanide compounds; a diene-aromatic alkenyl compound copolymer; vinyl cyanide-diene-aromatic alkenyl compound copolymer; aromatic alkenyl-diene-vinyl cyanide-N-phenylmaleimide copolymer; ethylene cyanide- (ethylene-diene-propylene (EPDM)) -aromatic alkenyl compound copolymers; vinyl chloride resin; chlorinated vinyl chloride resin; and so on. These resins may be used singly or in combination of two or more.

[ first layer ]

The first layer is a resin layer present on the surface of the master particle. The first layer contains at least one cationic resin selected from the group consisting of polyalkyleneimine, polyallylamine, and polyvinylamine.

The cationic resin may be any of polyalkyleneimine, polyallylamine, and polyvinylamine, and polyalkyleneimine is preferable in terms of increasing the rate of temporal biodegradation and reducing the rate of initial biodegradation.

The polyalkyleneimine is preferably a polyalkyleneimine having a structural unit containing an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms) and more preferably a polyethyleneimine, from the viewpoints of increasing the rate of temporal biodegradation and reducing the rate of initial biodegradation.

In particular, polyethyleneimine is a compound having high adhesion and high water absorption. This is because the amino group of polyethyleneimine forms a hydrogen bond with a hydroxyl group, an ionic bond with a carboxyl group, and a covalent bond with a carbonyl group. The reason for this is that polyethyleneimine has a polar group (amino group) and a hydrophobic group (vinyl group) in the structure, and thus has a property of easily bonding with different substances.

Further, polyethyleneimine is a compound having high cationic properties. Thus, polyethyleneimine exists as polycation under the condition of water, and neutralizes and adsorbs anionic substances.

Further, polyethyleneimine is a highly reactive compound because it has a primary or secondary amino group with high reactivity. Thereby easily reacting with various compounds.

Therefore, when polyethyleneimine is used as the polyalkyleneimine, the second layer containing the hydrophobic compound more firmly coats the mother particle, and tends to have a time-dependent biodegradation rate and a low initial biodegradation rate.

The number average molecular weight of the cationic resin is preferably 300 to 100000, more preferably 10000 to 85000, and still more preferably 50000 to 80000, from the viewpoint of increasing the rate of temporal biodegradation and decreasing the rate of initial biodegradation.

The number average molecular weight of the cationic resin was measured in terms of polystyrene using tetrahydrofuran by a gel permeation chromatography apparatus (GPC apparatus: HLC-8320GPC, column: TSKgel. alpha. -M, manufactured by Tosoh corporation).

[ second layer ]

The second layer is a compound layer present on the first layer. And, the second layer comprises an anionic or nonionic hydrophobic compound.

Examples of the anionic or nonionic hydrophobic compound include compounds having an anionic group (-COOH (carboxyl group), -SO)₃H (sulfone group), etc.), and a hydrophobic compound having no cationic group and no anionic group.

The hydrophobic compound is a compound that imparts hydrophobicity (specifically, a water contact angle) to biodegradable resin particles described later.

Examples of the hydrophobic compound include a siloxane compound, a hydrocarbon compound, a fatty acid compound, an acrylic resin, a polyester resin, and a urethane resin.

Among these, at least one selected from the group consisting of silicone compounds, hydrocarbon compounds, fatty acid compounds, acrylic resins, polyester resins, and urethane resins is preferable from the viewpoint of increasing the rate of temporal biodegradation and decreasing the rate of initial biodegradation.

Examples of the silicone compound include dimethylpolysiloxane, methylpolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, methylcyclopolysiloxane, various modified silicone oils (alkyl-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, fluorine-modified silicone oil, amino-modified silicone oil, etc.), MQ resin, silicone rubber, and the like.

Among these, the silicone compound is preferably at least one selected from the group consisting of dimethylpolysiloxane, methylpolysiloxane, MQ resin, and silicone rubber, in view of increasing the rate of temporal biodegradation and reducing the rate of initial biodegradation.

Here, MQ resin means a resin having [ (CH) as a monofunctional siloxane unit₃)₃SiO_1/2]And as tetrafunctional siloxane units [ SiO ]_4/2]The siloxane resin of Q unit (2).

Commercially available silicone compounds include those manufactured by shin-Etsu chemical industries, Inc. (KM-902, KM-903, KM-910, KM-9729, POLON-MN-ST, KM-9737A, KM-9782, KM-9738A, KM-752T, POLON-MF-33, KM-9717, X-51-1302M (MQ resin), POLON-MF-56, KM-2002-L-1, KM-2002-T, KM-9772, KM-9749, POLON-MF-40, KM-9729, X-52-1133, etc.), and those manufactured by Asahi Kawakk Silicone K.K. (BELSIL DM3112 VP).

Examples of the hydrocarbon compound include petroleum waxes (paraffin wax, microcrystalline wax, petrolatum wax, and the like) and synthetic hydrocarbon waxes (polyethylene wax, polypropylene wax, polybutene wax, fischer tropsch wax, and the like).

Among these, the hydrocarbon compound is preferably at least one selected from the group consisting of paraffin wax, microcrystalline wax, polyethylene wax, and polypropylene wax, in order to increase the rate of temporal biodegradation and decrease the rate of initial biodegradation.

Commercially available products of the hydrocarbon compound include microcrystalline wax (EMUSTAR-0001, etc.) manufactured by Nippon Seikagaku K.K., paraffin wax (EMUSTAR-0135, etc.) manufactured by Nippon Seikagaku K.K., paraffin wax (AQUACER497, etc.) manufactured by BYK Seikagaku K.K., polyethylene wax (AQUACER507, AQUACER840, AQUACER1547, AQUACER272, etc.), polyethylene wax (Hitech E-2213, Hitech E-6324, etc.) manufactured by Toho chemical Co., Ltd., polypropylene wax (AQUACER593, etc.) manufactured by BYK Seik K, polypropylene (Hitech P-9018, Hitech P-5060P, etc.) manufactured by Toho chemical Co., Ltd.

Examples of the fatty acid compound include vegetable oils containing fatty acids (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 (jojoba oil), cocoa butter, shea butter, chinaberry oil, safflower oil, wood wax, candelilla wax, rice bran wax, carnauba wax, and the like).

Among these, at least one selected from the group consisting of carnauba wax, rice bran wax, candelilla wax, palm wax, castor oil wax, soybean oil wax, and sunflower oil wax is preferable from the viewpoint of increasing the temporal biodegradation rate and decreasing the initial biodegradation rate.

Commercially available products of the fatty acid compounds include carnauba wax (EMUSTAR-0413 (carnauba wax), rice bran wax (AQUASPROUT-7300, etc.) manufactured by Japan wax Kagaku corporation, palm wax (AQUASPROUT-7100, etc.) manufactured by Japan wax Kagaku corporation, castor oil wax (AQUASPROUT-7500, etc.) manufactured by Japan wax Kagaku corporation, soybean oil wax (AQUASPROUT-7200, etc.) manufactured by Japan wax Kagaku corporation, sunflower seed oil wax (AQUASPROUT-7400, etc.) manufactured by Japan wax Kagaku corporation, palm oil wax (Cuckoo Ace, etc.) manufactured by Japan wax Kagaku corporation, etc.

Examples of the acrylic resin include known acrylic resins such as a polymer of acrylic acid and a polymer of alkyl acrylate.

As the commercially available acrylic resins, there may be mentioned, for example, acrylic resins manufactured by Daihu chemical Co., Ltd. (3WX-2015, 3MF-320, 3MF-333, 3MF-407, etc.), and acrylic resins manufactured by DIC corporation (Coat SFC-6440, Voncoat CE-6270, Voncoat CE-6400, Voncoat CF-2800, etc.).

Examples of the polyester resin include known polyester resins such as polycondensates of polyhydric alcohols and polyhydric alcohols, and ring-opening polycondensates of cyclic lactams.

Examples of commercially available polyester resins include polyester resins (A-110F, A-160P, A-520, A-613D, A-615GE, A-640, A-645GH, A-647GEX, etc.) manufactured by Katsuga oil and fat Co.

Examples of the urethane resin include known urethane resins such as polyester polyurethane, polyether polyurethane, and polycarbonate polyurethane. As the urethane resin, a material having a shell layer of a urethane polymer around a core of an acrylic polymer can be used.

Examples of commercially available urethane resins include urethane resins manufactured by Dachen Fine chemical Co., Ltd. (WEM-031U, WEM-200U, WEM-321U, WEM-3000, WBR-016U, WBR-2101, etc.).

[ contents of respective layers ]

In the biodegradable resin particle of the present embodiment, the mass ratio of the content of the cationic resin in the first layer to the content of the hydrophobic compound in the second layer (content of the cationic resin/content of the hydrophobic compound) is preferably 0.05 to 20, more preferably 0.1 to 10, and still more preferably 0.1 to 3, from the viewpoint of increasing the temporal biodegradation rate and decreasing the initial biodegradation rate.

The content of the cationic resin in the mother particle is preferably 0.05 to 15 mass%, more preferably 0.1 to 10 mass%, and still more preferably 0.1 to 3 mass%, from the viewpoint of increasing the rate of temporal biodegradation and decreasing the rate of initial biodegradation.

In addition, the content of the hydrophobic compound in the mother particle is preferably 0.05 to 15 mass%, more preferably 0.1 to 10 mass%, and still more preferably 0.1 to 3 mass% in terms of increasing the temporal biodegradation rate and decreasing the initial biodegradation rate.

Here, the respective contents of the cationic resin and the hydrophobic compound (i.e., the content of the cationic resin in the first layer and the content of the hydrophobic compound in the second layer) were measured as follows. The content of the cationic resin is determined by the difference between the amount of the cationic resin treated and the amount of the cationic resin obtained by drying the treated supernatant. Similarly, the content of the hydrophobic compound is determined by the difference between the treatment amount of the hydrophobic compound and the hydrophobic compound obtained by drying the treated supernatant.

[ Properties of biodegradable resin particles ]

In the biodegradable resin particle of the present embodiment, the water contact angle of the pellet obtained by granulating the biodegradable resin particle is 70 ° to 120 °.

When the water contact angle is in the above range, the initial biodegradation rate decreases.

The water contact angle is preferably 72 ° to 110 °, more preferably 75 ° to 105 °.

Regarding the water contact angle, the biodegradable resin pellets thus produced were pelletized, and then 1. mu.l of water droplets were dropped on the pellet surface by a syringe using a contact angle meter (model: CA-X, manufactured by Kyowa interface science) under an environment of 23 ℃ for 1 minute and then measured.

The biodegradable resin pellet of the present embodiment has a biodegradability of 20% or less under aerobic conditions after 3 months, as measured by a method according to ISO-14855-2 (2018).

When the aerobic biodegradation rate after 3 months is in the above range, the initial biodegradation rate decreases.

The aerobic-condition biodegradation rate after 3 months is preferably 15% or less, more preferably 10% or less, and further preferably 5% or less. The lower limit is preferably 0%, for example, 1%.

The biodegradable resin pellet of the present embodiment has a ratio of the aerobic-condition biodegradation rate after 6 months to the aerobic-condition biodegradation rate after 3 months (aerobic-condition biodegradation rate after 6 months/aerobic-condition biodegradation rate after 3 months) measured by the method according to ISO-14855-2 (2018) of preferably 1.20 or more, more preferably 1.50 or more, and still more preferably 2.00 or more.

The ratio of the aerobic-condition biodegradation rate after 12 months and the aerobic-condition biodegradation rate after 3 months (aerobic-condition biodegradation rate after 12 months/aerobic-condition biodegradation rate after 3 months) measured by the method according to ISO-14855-2 (2018) is preferably 3.50 or more, more preferably 5.00 or more, further preferably 10.00 or more, further preferably 15.00 or more, and further preferably 20.00 or more.

In the biodegradable resin pellet of the present embodiment, when the surface of the biodegradable resin pellet is measured by X-ray photoelectron spectroscopy (XPS), the relationship among the carbon atomic weight Cs, the silicon atomic weight Sis, and the oxygen atomic weight Os satisfies the formula a: (Cs + Sis)/Os ≧ 3.

When formula a is satisfied, the initial biodegradation rate decreases. Further, the lipophilicity of the surface of the biodegradable resin particle is improved, and the oil absorption of the resin particle is improved.

The value of "(Cs + Sis)/Os" is preferably 4 or more, more preferably 7 or more, from the viewpoint of reducing the initial biodegradation rate and increasing the oil absorption rate. In view of the rate of temporal biodegradation, the upper limit of the value of "(Cs + Sis)/Os" is, for example, 95.

In order to set the value of "(Cs + Sis)/Os" in the above range, it is preferable to coat a second layer containing a hydrophobic compound on the mother particle.

In the biodegradable resin pellet of the present embodiment, when the surface of the biodegradable resin pellet after the surface etching for 3 minutes is measured by X-ray photoelectron spectroscopy (XPS), the relationship among the carbon atomic weight Ce, the silicon atomic weight Sie, and the oxygen atomic weight Oe preferably satisfies the formula B: (Ce + Sie)/Oe ≧ 3.

When the formula B is satisfied, the period during which the biodegradation rate is reduced becomes long. And easily maintain a high oil absorption. Further, even if a mechanical load is applied to the biodegradable resin particles (for example, the biodegradable resin particles are stirred by ultrasonic homogenization or the like), the oil absorption rate is not easily decreased.

The value of "(Ce + Sie)/Oe" is more preferably 4 or more, and still more preferably 7 or more, from the viewpoint of initial biodegradation rate maintenance and oil absorption maintenance. In view of the rate of biodegradation with time, the upper limit of the value of "(Ce + Sie)/Oe" is, for example, 95 or less.

In order to set the value of "(Ce + Sie)/Oe" in the above range, it is preferable that the mother particle is coated with a first layer containing a cationic resin and a second layer containing a hydrophobic compound in this order.

Here, the method of measuring each atomic weight (atom%) by X-ray photoelectron spectroscopy (XPS) is as follows. The measurement was performed on the produced biodegradable resin particles.

The XPS measurement apparatus used "PHI 5000 Versa Probe II manufactured by ULVAC. PHI", and the X-ray source used monochromatic AlK alpha rays, and the acceleration voltage was set at 15kV for measurement. Specifically, let the analysis region beThe number of each atom (carbon atom, silicon atom, and oxygen atom) is obtained based on the spectrum of each atom (carbon atom, silicon atom, and oxygen atom) measured, and each atomic weight (carbon atomic weight, silicon atomic weight, and oxygen atomic weight) with respect to the total atomic weight in the measurement region is calculated.

The carbon atomic weight, silicon atomic weight, and oxygen atomic weight when the surface of the biodegradable resin particle before etching was measured were determined as carbon atomic weight Cs, silicon atomic weight Sis, and oxygen atomic weight Os.

The carbon atomic weight, silicon atomic weight, and oxygen atomic weight of the biodegradable resin particle surface after the surface etching for 3 minutes were determined as the carbon atomic weight Ce, the silicon atomic weight Sie, and the oxygen atomic weight Oe.

Wherein, when the compound included in the second layer does not include silicon atoms, the silicon atom amount is 0 atom%.

The surface etching was performed on the biodegradable resin particles prepared as follows.

As an apparatus for etching, PHI5000 Versa Probe II manufactured by ULVAC. PHI was used, and etching was performed for 3 minutes under conditions of an acceleration voltage of 5kV and a scanning area of 2 mm. times.2 mm by an argon cluster etching method using argon as an etching gas.

The volume average particle diameter of the biodegradable resin particles is preferably 3 μm to 100 μm, more preferably 5 μm to 70 μm, and still more preferably 8 μm to 60 μm.

When the particle diameter of the biodegradable resin particles is 3 μm or more, the number of particles per unit weight is not too large, and thus the degradation of the biodegradation rate can be suppressed. On the other hand, when the particle diameter of the biodegradable resin particles is 100 μm or less, the specific surface area becomes high, and the biodegradation rate can be further improved.

Therefore, the volume average particle diameter of the biodegradable resin particles is preferably in the above range.

The large-diameter-side particle size distribution index GSDv of the biodegradable resin particles is preferably 1.5 or less, more preferably 1.3 or less, and still more preferably 1.2 or less.

When the particle size distribution of the biodegradable resin particles is nearly uniform, regular hydrolysis can be performed by providing a certain chance of contacting water, and the biodegradation rate can be further increased.

The volume average particle diameter and the major diameter side particle size distribution index GSDv of the biodegradable resin particles were measured as follows.

Particle diameters were measured by an LS particle size distribution measuring apparatus "Beckman Coulter LS 13320 (manufactured by Beckman Coulter corporation)", and cumulative distribution of particle diameters was plotted from the small diameter side on a volume basis, and a particle diameter at which the cumulative particle diameter reached 50% was obtained as a volume average particle diameter.

On the other hand, a cumulative distribution of particle diameters is plotted from the small diameter side on a volume basis, and a particle diameter at which 50% is cumulated is defined as a number average particle diameter D50v, and a particle diameter at which 84% is cumulated is defined as a number average particle diameter D84 v. And is represented by the formula GSDv ═ D84v/D50v^1/2And calculating the large-diameter side particle size distribution index GSDv.

[ Process for producing biodegradable resin particles ]

The method for producing the biodegradable resin particle according to the present embodiment includes, for example, a method including the steps of:

a first step of mixing an aqueous dispersion in which mother particles are dispersed with an aqueous solution containing a cationic resin; and

and a second step of taking out the mother particles from the mixed solution to obtain an aqueous dispersion in which the mother particles are dispersed, mixing the aqueous dispersion with an emulsion solution of an anionic or nonionic hydrophobic compound, and drying the mixture.

The following is a detailed description.

A first step

In the first step, mother granules are prepared.

The following methods can be mentioned as examples of the method for producing the mother particle.

1) Kneading each component, pulverizing the obtained kneaded product, and classifying to obtain granular material

2) Dry process for producing granular material by changing the shape of granular material obtained by kneading and pulverizing method by mechanical impact or thermal energy

3) An aggregation-combination method comprising mixing particle dispersions of the respective components, aggregating the particles in the dispersion, and heating and fusing the aggregated particles to obtain granules

4) Dissolving and suspending method comprising suspending an organic solvent in which each component is dissolved in an aqueous solvent and granulating a granular material containing each component

Among these, wet methods such as the coagulation-coagulation method and the dissolution suspension method are preferable from the viewpoint of obtaining biodegradable resin particles having a volume average particle diameter and a large-diameter side particle size distribution index GSDv, which will be described later.

Then, an aqueous dispersion in which the obtained mother particle is dispersed is prepared. The mother particles may be acid washed prior to preparing the aqueous dispersion.

Next, the aqueous dispersion in which the mother particles are dispersed is mixed with an aqueous solution containing a cationic resin. Thereby, for example, the hydroxyl group of the resin contained in the mother particle reacts with the amine site of the cationic resin to form a first layer.

A second step

In the second step, the mother particles forming the first layer are removed from the mixed solution. The mother particles are removed, for example, by filtering the mixed solution. The withdrawn mother granules may be washed with water. Thereby removing unreacted cationic resin.

Next, after preparing an aqueous dispersion in which the mother particles are dispersed, the aqueous dispersion is mixed with an emulsion solution of an anionic or nonionic hydrophobic compound. Thereby, an emulsion of the hydrophobic compound is adsorbed on the first layer of the mother particle.

Thereafter, when the mixed solution is dried, the emulsion state of the hydrophobic compound is broken, and the hydrophobic compound forms a film on the first layer. Thereby forming a second layer.

The biodegradable resin particles according to the present embodiment are obtained through the above steps.

Examples of the applications of the biodegradable resin particles of the present embodiment include particulate bodies of cosmetic base materials, rolling agents (ローリング), abrasives, scrubbing agents, display spacers, bead-forming materials, light diffusion particles, resin reinforcing agents, refractive index control agents, biodegradation accelerators, fertilizers, water-absorbing particles, and toner particles.

Examples

The resin composition and the resin molded article according to the present embodiment will be described in more detail below with reference to examples. The materials, amounts, proportions, treatment processes and the like shown in the following examples can be appropriately modified within a range not departing from the gist of the present invention. Therefore, the resin composition and the resin molded article of the present embodiment should not be construed as being limited to the specific examples shown below.

< preparation of respective materials >

The following materials were prepared.

[ biodegradable resin of mother particle ]

DAC: "L-50" manufactured by Daicel, Inc., cellulose diacetate and a weight-average degree of polymerization of 570

CAB: istmann chemical 'CAP 504-0.2', cellulose acetate propionate, weight average polymerization degree 133, acetyl substitution degree 0.04, propionyl substitution degree 2.09

CAP: cellulose acetate propionate, weight-average degree of polymerization 716, degree of substitution by acetyl group 0.18, degree of substitution by propionyl group 2.49

PLA: polylactic acid, weight average molecular weight 180000

PHA: polyhydroxyalkanoates

PBS: poly (butylene succinate) and weight average molecular weight of 200000

PBSA: polybutylene succinate-adipate with weight-average molecular weight of 110000

PBAT: polybutylene terephthalate-adipate with weight-average molecular weight of 100000

PETS: polyethylene terephthalate/succinate copolymer, weight average molecular weight 150000

[ plasticizer for mother particle ]

CDNl: cardolite 'NX-2503', hydroxyethylated cardanol, and having a molecular weight of 296-320

CDN 2: cardolite 'Ultra LITE 513', glycidyl ether of cardanol, and molecular weight of 354-361.

CDN 3: alkyl-modified novolak epoxy resin "EPICLON 865-alkyl-modified product" available from DIC corporation

DBA: adipic acid diisobutyl ester

ATBC: o-acetyl triethyl citrate

DPS: sebacic acid diisopropyl ester

[ cationic resin of the first layer ]

PEI: the number average molecular weight Mn of the polyethyleneimine and the material used is shown in table 1.

PAA: polyallylamine and the number average molecular weight Mn of the material used are shown in table 1.

PVAM: the number average molecular weight Mn of polyvinylamine and the material used are shown in table 1.

[ anionic or nonionic hydrophobic Compound of the second layer ]

EMUSTAR-0135: solid paraffin manufactured by Japan wax Fine Co., Ltd

POLON-MN-ST: dimethicone (dimethyl silicone) manufactured by shin-Etsu chemical Co., Ltd

KM-9717: MQ resin manufactured by shin-Etsu chemical industries Co., Ltd

Belsil DM3112 VP: dimethicone (dimethylsiloxane) manufactured by Asahi Wakka Silicone K.K.)

Hitech E-2213: polyethylene wax produced by Toho chemical Co., Ltd

Hitech P-9018: polypropylene wax manufactured by Toho chemical Co., Ltd

EMUSTAR-0413: carnauba wax manufactured by japan wax essences co

3 MF-320: acrylic resin manufactured by Dacheng Fine chemical Co., Ltd

A-647 GEX: polyester resin manufactured by Katsuma oil Co Ltd

WBR-016U: urethane resin produced by Dacheng Fine chemical Co., Ltd

Examples A1 to A30, B1 to B29, comparative examples A1 to A2, and B1 to B2

(preparation of resin pellets)

The pellets were kneaded at the compounding ratios shown in tables 1 to 2 by a twin-screw kneader (TEX 41SS, manufactured by TOSHIBA MACHINE Co., Ltd.) while adjusting the barrel temperature, to obtain resin compositions (hereinafter referred to as resin pellets) in pellet form.

(preparation of mother granule)

When DAC, CAB, and CAP were used as the resin, the mother particles were obtained as follows.

300g of the resin pellets were completely dissolved in 700g of methyl ethyl ketone. This was added to an aqueous liquid in which 100g of calcium carbonate, 4g of carboxymethyl cellulose, and 200g of methyl ethyl ketone were dispersed in 1100g of pure water, and the mixture was stirred for 3 hours. 10g of sodium hydroxide was added thereto, heated to 80 ℃ and stirred for 3 hours to remove methyl ethyl ketone. After the residue was filtered, it was again dispersed in pure water to obtain a slurry of mother particles.

On the other hand, when a resin other than DAC, CAB, and CAP is used as the resin, the mother particle is obtained as follows.

2000g of the resin pellets were melt-kneaded (kneader), and the kneaded product was rolled with 2 rolls and formed into a sheet, and then the formed product was cooled and coarsely pulverized with a pulverizer. This coarsely pulverized material was finely pulverized with a jet mill, thereby obtaining mother granules. The mother particles were dispersed in pure water to obtain a slurry of the mother particles.

(preparation of biodegradable resin pellets)

Biodegradable resin pellets were obtained as follows using the materials of the first layer and the second layer shown in tables 1 to 2, so that the content of each layer was in the amount shown in tables 1 to 2.

After the slurry of the mother particles was adjusted to 20% in terms of solid content, a predetermined amount of a solution of the cationic resin was added in terms of pure content relative to the amount of the solid content contained in the slurry, and the mixture was stirred at 25 ℃ for 1 hour. After completion of the stirring, the residue was filtered, redispersed in pure water, adjusted to 20% of solid content, and a predetermined amount of hydrophobic compound was added in terms of pure product relative to the amount of solid content contained in the slurry, followed by stirring at 25 ℃ for 1 hour. After completion of the stirring, the residue was filtered, and the solid content was freeze-dried to obtain biodegradable resin particles.

Through the above steps, biodegradable resin particles are obtained.

In comparative examples a2 and B2, the first layer was not formed, and the second layer was formed (addition treatment of the hydrophobic compound) at the same content as in examples a1 and B1, but the hydrophobic compound was not easily adsorbed, and the content in the second layer was 0.0001%.

< Properties of biodegradable resin particles >

The following characteristics of the biodegradable resin pellets were measured in accordance with the following methods. The results are shown in tables 1 to 2.

Water contact Angle (in the table, the contact Angle)

Volume average particle diameter D50v

Value of (Cs + Sis)/Os (noted in the Table as "(C + Si)/O ratio T ═ 0")

Value of (Ce + Sie)/Oe (noted as "(C + Si)/O ratio T-3" in the table)

< hydrolysis resistance >

The hydrolysis resistance of the biodegradable resin pellets was evaluated as follows. Here, the evaluation of hydrolysis resistance was conducted only on the biodegradable resin pellets of examples B1 to B29 and comparative examples B1 to B2.

50g of biodegradable resin pellets were sealed in a bag made of #508/585-1 μ nylon mesh (mesh size: 1 μm), and the bag was immersed in distilled water adjusted to 50 ℃ and pH7.8 for 90 days. Thereafter, the nylon net containing the resin particles was taken out, and the resin particles in the nylon net were vacuum-dried. The mass of the biodegradable resin particles after vacuum drying was measured, and the mass reduction rate of the biodegradable resin particles was measured. And evaluated according to the following criteria.

A: the mass reduction rate is more than 0 percent and less than 10 percent

B: the mass reduction rate is more than 10 percent and less than 20 percent

C: the mass reduction rate is more than 20 percent and less than 30 percent

D: the mass reduction rate is more than 30 percent

< oil absorption >

Initial oil absorption-

After 1g of biodegradable resin particles were dispersed in 10g of linseed oil, centrifugation was performed at 10000rpm for 20 minutes, and the supernatant was gently removed, the mass of the biodegradable resin particles was measured. The oil absorption was then calculated by the following formula.

Formula (la): oil absorption (mass increase after centrifugation/mass before dispersion in linseed oil) × 100

Oil absorption after stirring

1g of biodegradable resin particles was dispersed in 10g of linseed oil, and an ultrasonic homogenizer was placed in the obtained solution, and ultrasonic waves of 20kHz were irradiated to stir the solution for 10 minutes. The stirred solution was centrifuged at 10000rpm for 20 minutes, and the supernatant was gently removed, and then the mass of the biodegradable resin pellets was measured. And calculating the oil absorption rate by the formula.

The oil absorption was evaluated according to the following criteria.

(A) The method comprises the following steps Over 110 percent

(B) The method comprises the following steps 90% to 109%

(C) The method comprises the following steps 70% to 89% below

(D) The method comprises the following steps Less than 69%

< measurement of biodegradability >

The obtained biodegradable resin pellets were used to measure the biodegradation rate under aerobic conditions after 3 months, 6 months and 12 months by a method in accordance with ISO-14855-2 (2018). The results are shown in tables 1 to 2.

[ tables 1-2]

[ tables 2-2]

From the above results, it was found that the biodegradable resin particles of the present example had a biodegradation rate (biodegradation rate over time) and a lower initial biodegradation rate (initial biodegradation rate) as compared with the biodegradable resin particles of the comparative examples.

It is also found that the biodegradable resin particles of the present example also have a higher oil absorption rate than the biodegradable resin particles of the comparative example.

It is also found that the biodegradable resin particles of the present example, in which a specific plasticizer is added to a cellulose resin as a biodegradable resin and the obtained mother particle is sequentially coated with a first layer containing a cationic resin and a second layer containing a hydrophobic compound, are biodegradable and have excellent hydrolysis resistance.