JP7799268B2 - Polymer fine particles - Google Patents

Description

The present invention relates to polymeric microparticles.

Polymer microparticles composed of a copolymer of rotaxane and (meth)acrylate have been known (see, for example, Patent Document 1).

JP 2018-30928 A

Under these circumstances, the present inventors synthesized polymer microparticles with reference to Patent Document 1, and found that further improvements in mechanical properties (particularly fracture energy) were desirable.

In light of the above-mentioned circumstances, the present invention aims to provide polymeric microparticles with excellent mechanical properties (particularly breaking energy).

The inventors' research has revealed that the mechanical properties (particularly the fracture energy) of the resulting polymer microparticles change depending on the length (number of carbon atoms) of the rotaxane's axial molecule. Furthermore, it has been found that mechanical properties are improved when the axial molecule is short and has a specific range of carbon atoms, compared to when the axial molecule is a polymer, as in the examples of Patent Document 1. The present invention is based on this finding, and is specifically as follows.

(1) A polymeric microparticle comprising a copolymer of a rotaxane having a cyclic molecule and an axis molecule passing through the cyclic molecule, and a (meth)acrylate,
at least one of the cyclic molecule and the axial molecule has a polymerizable unsaturated group-containing group,
The polymeric fine particles have an axial molecule having 4 to 12 carbon atoms.
(2) The polymeric fine particles according to (1) above, wherein two or more kinds of (meth)acrylates are used in combination as the (meth)acrylate.
(3) The polymeric fine particles according to (1) or (2) above, wherein the ratio of the rotaxane to the (meth)acrylate is 0.001 to 10 mol %.
(4) The polymeric microparticle according to any one of (1) to (3) above, wherein both the cyclic molecule and the axial molecule have a polymerizable unsaturated group-containing group.
(5) Polymeric microparticles according to any one of (1) to (4) above, having a harmonic mean diameter of 2000 nm or less.
(6) Polymeric microparticles according to any one of (1) to (5) above, having a swelling degree of 18 or more.
(7) The polymeric fine particles according to any one of (1) to (6) above, wherein the polymerizable unsaturated group of the polymerizable unsaturated group-containing group is a vinyl group, an acrylic group, or a methacrylic group.
(8) Polymeric microparticles according to any one of (1) to (7) above, having a breaking elongation of more than 400%.
(9) Polymeric microparticles according to any one of (1) to (8) above, having a residual strain of more than 25%.

As shown below, the present invention can provide polymeric microparticles with excellent mechanical properties (particularly fracture energy).

The polymeric fine particles of the present invention will be described below.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In addition, in this specification, each component may be used alone or in combination of two or more. When two or more components are used in combination, the amount of the component refers to the total amount unless otherwise specified.
In addition, in this specification, (meth)acrylic means acrylic or methacrylic, and (meth)acrylate means acrylate or methacrylate.

[Polymer fine particles]
The polymeric microparticles of the present invention are
A polymeric microparticle comprising a copolymer of a rotaxane having a cyclic molecule and an axis molecule passing through the cyclic molecule, and a (meth)acrylate,
at least one of the cyclic molecule and the axial molecule has a polymerizable unsaturated group-containing group,
The polymer particles have an axial molecule having 4 to 12 carbon atoms.

[Specific Rotaxane]
The rotaxane used in the polymeric microparticle of the present invention (hereinafter also referred to as "specific rotaxane") is a rotaxane having a cyclic molecule and an axle molecule passing through the cyclic molecule, wherein the axle molecule has 4 to 12 carbon atoms.

<Cyclic molecules>
The cyclic molecule is not particularly limited, but specific examples include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, crown ethers, and derivatives thereof.
The cyclic molecule may have a substituent, such as a hydroxy group, an acetyl group, a propionyl group, a hexanoyl group, a methyl group, an ethyl group, a propyl group, a 2-hydroxypropyl group, a 1,2-dihydroxypropyl group, a cyclohexyl group, a butylcarbamoyl group, a hexylcarbamoyl group, a phenyl group, a polycaprolactone group, an alkoxysilane group, an acryloyl group, a methacryloyl group, a cinnamoyl group, a polymer chain (such as a polycaprolactone group or a polycarbonate group), or a derivative thereof.
The cyclic molecule is preferably a crown ether or a derivative of a crown ether, because this provides a better effect of the present invention.

The number of cyclic molecules contained in one specific rotaxane is not particularly limited, but it is preferably 1, as this provides a superior effect of the present invention.

<Axis molecule>
The axial molecule is a shaft-like (rod-like) molecule that passes through the cyclic molecule, and usually has bulky terminal functional groups at both ends thereof to prevent the cyclic molecule from being detached.

(Shaft-shaped part)
The axial molecule is not particularly limited, but is preferably a divalent aliphatic hydrocarbon group, more preferably an alkylene group, for reasons of superior effect of the present invention.
One or more carbon atoms constituting the divalent aliphatic hydrocarbon group may be replaced by -O-, -S-, -SO ₂ -, -N(R)- (R: hydrogen atom or substituent), -CO-, -COO-, -CONR- (R: hydrogen atom or substituent), or a group combining these.
For reasons of better effects of the present invention, the divalent aliphatic hydrocarbon group is preferably one in which at least one carbon atom constituting the divalent aliphatic hydrocarbon group is replaced by -O-, -S-, -SO ₂ -, -N(R)- (R: hydrogen atom or substituent), -CO-, -COO-, -CONR- (R: hydrogen atom or substituent), or a group combining these.

(terminal functional group)
As described above, the axial molecule generally has bulky terminal functional groups at both ends thereof to prevent the cyclic molecule from being released.
The terminal functional group is not particularly limited, and specific examples thereof include an aromatic hydrocarbon group, an aromatic heterocyclic group, a dinitrophenyl group, an adamantane group, a trityl group, a fluorescein group, a silsesquioxane group, a pyrene group, and derivatives thereof, each of which may have a substituent.
The axial molecule is preferably an aromatic hydrocarbon group which may have a substituent, and more preferably a phenyl group which may have a substituent, for reasons that the effects of the present invention are more excellent.

<Number of carbon atoms>
As mentioned above, the number of carbon atoms in the axial molecule is 4 to 12. Among these, it is preferable that the number is 6 to 10, because this provides a better effect of the present invention.
The "number of carbon atoms in the axis molecule" refers to the number of carbon atoms in the axis-like portion of the axis molecule, and does not include the number of carbon atoms in the terminal functional group described above and the number of carbon atoms in a substituent (for example, a polymerizable unsaturated group-containing group described later) that the axis molecule has.

<Polymerizable unsaturated group-containing group>
As described above, at least one of the cyclic molecule and the axis molecule has a polymerizable unsaturated group-containing group. In particular, it is preferable that both the cyclic molecule and the axis molecule have a polymerizable unsaturated group-containing group, because the effects of the present invention are more excellent. When both the cyclic molecule and the axis molecule have a polymerizable unsaturated group-containing group, a sliding effect of the specific rotaxane occurs, and flexibility and toughness are further improved.
Furthermore, when the above-mentioned axial molecule has the above-mentioned polymerizable unsaturated group-containing group, it is preferable that the axial portion of the axial molecule has the above-mentioned polymerizable unsaturated group-containing group.
The cyclic molecule and the axial molecule may each have two or more polymerizable unsaturated group-containing groups.

The polymerizable unsaturated group-containing group refers to a polymerizable unsaturated group or a group containing a polymerizable unsaturated group, and is a group represented by -LP (wherein L represents a single bond or a divalent linking group, and P represents a polymerizable unsaturated group).
The polymerizable unsaturated group of the polymerizable unsaturated group-containing group is not particularly limited, and specific examples thereof include a vinyl group, an acrylic group (acryloyl group), a methacrylic group (methacryloyl group), an acryloyloxy group, a methacryloyloxy group, etc. Among these, an acryloyloxy group and a methacryloyloxy group are preferred because they provide better effects of the present invention.

When L in the above -LP is a divalent linking group, specific examples include a divalent aliphatic hydrocarbon group (particularly an alkylene group), a divalent aromatic hydrocarbon group, -O-, -S-, -SO ₂ -, -N(R)- (R: hydrogen atom or substituent), -CO-, -COO-, -CONR- (R: hydrogen atom or substituent), and groups combining these.

<Manufacturing method>
The method for producing the specific rotaxane is not particularly limited, and it can be produced by combining known methods.

[(Meth)acrylate]
The (meth)acrylate used in the polymeric microparticles of the present invention is not particularly limited, and specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, isononyl (meth)acrylate, isodecynonyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and methyl (meth)acrylate. (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, benzyl (meth)acrylate, dicyclohexyl (meth)acrylate, 2-dicyclohexyloxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, nonanediol di(meth)acrylate, 2-morpholinoethyl (meth)acrylate, 9-anthryl (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trans-1,4-cyclohexanediol di(meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, Examples of the acrylate include methoxydipropylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, poly(ethylene glycol-tetramethylene glycol) (meth)acrylate, poly(propylene glycol-tetramethylene glycol) (meth)acrylate, polyethylene glycol-polypropylene glycol (meth)acrylate, and glycidyl (meth)acrylate.

The above-mentioned (meth)acrylate is preferably an ester of acrylic acid or methacrylic acid with an alcohol having 1 to 10 carbon atoms, more preferably an ester of acrylic acid or methacrylic acid with an alcohol having 1 to 5 carbon atoms, and even more preferably an ester of acrylic acid or methacrylic acid with an alcohol having 1 to 3 carbon atoms, because this provides a more excellent effect of the present invention.

The above (meth)acrylates may be used alone or in combination of two or more. However, to obtain better effects of the present invention, it is preferable to use two or more in combination, and it is more preferable to use a combination of methyl (meth)acrylate and ethyl (meth)acrylate or methoxyethyl (meth)acrylate.

[Other Monomers]
The polymeric microparticles of the present invention may be copolymerized with other monomers in addition to the above-mentioned specific rotaxane and the above-mentioned (meth)acrylate, but the total ratio of the specific rotaxane and (meth)acrylate to all monomers (specific rotaxane, (meth)acrylate, other monomers) is preferably 90 mol% or more, more preferably 95 mol% or more, for the reason that the effects of the present invention are more excellent. The upper limit of the total ratio of the specific rotaxane and (meth)acrylate to all monomers is not particularly limited, and is 100 mol%.

[Specific Rotaxane/(Meth)acrylate]
The ratio of the specific rotaxane to the (meth)acrylate is preferably 0.001 to 10 mol %, more preferably 0.01 to 1 mol %, for reasons of better effects of the present invention.

[Harmonic mean diameter]
The harmonic mean diameter of the polymeric microparticles of the present invention is not particularly limited, but is preferably 2000 nm or less, more preferably 1000 nm or less, and even more preferably 500 nm or less, because the effects of the present invention are more excellent. The lower limit of the harmonic mean diameter is also not particularly limited, but is preferably 10 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, and especially preferably 200 nm or more, because the effects of the present invention are more excellent.
The harmonic mean diameter is a harmonic mean diameter in DMF (dimethylformamide) measured by the cumulant method using a particle size measuring device (Zetasizer Nano S manufactured by Malvern Instruments).

[Swelling degree]
The swelling degree of the polymeric microparticles of the present invention is not particularly limited, but in order to obtain a more excellent effect of the present invention, it is preferably 10 or more, more preferably 18 or more, and even more preferably 20 or more. The upper limit of the swelling degree is not particularly limited, but in order to obtain a more excellent effect of the present invention, it is preferably 100 or less.
The swelling degree is a parameter expressed by the following formula.
Swelling degree = (D _h (DMF)) ³ / (D _h (water)) ³
Here, D _h (DMF) represents the harmonic mean diameter in DMF as described above, and D _h (water) represents the harmonic mean diameter in water, and the measurement method is the same as that for the harmonic mean diameter in DMF as described above, except that water is used instead of DMF.

[Molecular weight]
The weight average molecular weight of the polymeric fine particles of the present invention is not particularly limited, but is preferably 1,000 to 1,000,000, and more preferably 10,000 to 100,000, for reasons of better effects of the present invention.
The weight average molecular weight is a value calculated as a standard polystyrene based on a measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[Elongation at break]
The breaking elongation of the polymeric microparticles of the present invention is not particularly limited, but is preferably more than 400% because the effects of the present invention are more excellent. The upper limit of the breaking elongation is not particularly limited, but is preferably 1000% or less because the effects of the present invention are more excellent.
The breaking elongation was measured as follows.
A 5 cm square film (thickness: approximately 0.4 mm) was prepared using a dispersion of polymer microparticles (5% by mass, 7 mL) (centrifugally purified and dialyzed), and four 1 cm x 4 cm films were cut out from the obtained film, and a 2 mm notch was made in the center of the longitudinal direction using a diamond cutter. The obtained test specimens for tensile testing were subjected to a tensile test (load cell: 50 N, elongation rate: 10 mm/min, test temperature: 25 ° C.) using a Tensilon tensile tester.

[Residual strain]
The residual strain of the polymeric microparticles of the present invention is not particularly limited, but in order to obtain a more excellent effect of the present invention, it is preferably more than 25%, more preferably 30% or more, and even more preferably 40% or more. The upper limit of the residual strain is not particularly limited, but in order to obtain a more excellent effect of the present invention, it is preferably 80% or less.
The residual strain was measured as follows.
A 5 cm square film (thickness: approximately 0.4 mm) was prepared using a dispersion of polymer microparticles (5% by mass, 7 mL) (centrifugally purified, dialyzed), and a stress of 100 kPa was applied to the obtained film for 10 hours, followed by relaxation for 14 hours, after which the residual strain was measured.

[Application]
The polymeric fine particles of the present invention are useful as additives in, for example, rubber compositions, adhesive compositions, and coating compositions.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[Rotaxane Synthesis]
The specific rotaxane and the comparative rotaxane were synthesized as follows.

<Specific rotaxane>
A specific rotaxane was synthesized as follows.

(Synthesis of Axial Moiety Precursor)
6-Amino-1-hexanol (2.9 g) was added to a solution of 3,5-dimethylbenzaldehyde (3.3 g) in tetrahydrofuran (THF) (250 mL), and the mixture was stirred at room temperature for 24 hours. After the solvent was evaporated, the residue was dissolved in methanol (250 mL) and added dropwise to NaBH ₄ (2.9 g). The resulting mixture was stirred at room temperature for 5 hours, and after the solvent was evaporated, the residue was dissolved in chloroform (100 mL), and the organic phase was washed with distilled water. The resulting organic phase was dried over magnesium sulfate, and the organic solvent was evaporated to give N-(3,5-dimethylbenzyl)-6-hydroxyhexylamine (Compound 1) (5.8 g) as a colorless oil.
Next, the obtained compound 1 was dissolved in methanol (100 mL), and 12N aqueous hydrochloric acid solution (8 mL) was added. This mixed solution was added dropwise to diethyl ether (1 L), yielding a solid precipitate, which was then filtered. The obtained solid was added to a saturated aqueous solution of hexafluorophosphate ammonium salt, and the resulting solution was added dropwise to methanol, yielding a precipitate. After filtering the obtained precipitate, the solid was washed with water and dried to yield N-(3,5-dimethylbenzyl)-6-hydroxyhexylammonium hexafluorophosphate salt (compound 2) (1.4 g) as a white solid.

(Synthesis of cyclic molecules)
2-Isocyanatoethyl methacrylate (1.4 mL) and dibutyltin dilaurate (0.2 mL) were added to a solution of hydroxymethyldibenzo-24-crown-8-ether (1.9 g) in methylene chloride (45 mL) at 0°C, and the mixture was stirred at room temperature for 48 hours. The resulting mixture was concentrated to 10 mL and poured into hexane to obtain a precipitate. The precipitate was dissolved in an ethyl acetate/hexane mixed solution (2/3) and purified using a silica column. 2.5 g of the desired cyclic molecule (Compound 3) was obtained.

(Rotaxane synthesis)
A mixed solution of compound 2 (150 mg) and compound 3 (260 mg) in methylene chloride (1 mL) was irradiated with ultrasound at room temperature until it became transparent. Dibutyltin dilaurate (1 mg) and 3,5-dimethylphenyl isocyanate (160 mg) were added to the solution and stirred at room temperature for 5 hours. Methanol was then added to the solution to deactivate unreacted isocyanate. After distilling off the volatile components, the residue was dissolved in THF (4 mL). Triethylamine (810 mg) and 2-isocyanatoethyl methacrylate (620 mg) were added to the THF solution and stirred at room temperature for 2.5 days. After distilling off the volatile components from the solution, the target rotaxane (described below) (290 mg) was obtained by column purification. The resulting rotaxane is also referred to as a specific rotaxane (RC).

The obtained rotaxane is a rotaxane having a cyclic molecule (compound 3) and an axis molecule passing through the cyclic molecule,
the axis molecule has bulky terminal functional groups (dimethylphenyl groups) at both ends thereof to prevent the cyclic molecule from being detached,
the cyclic molecule has a polymerizable unsaturated group (methacryloyloxy group)-containing group,
the axial molecule has a polymerizable unsaturated group (methacryloyloxy group)-containing group (-C(=O)NHC ₂ H ₄ OC(=O)C(CH ₃ )=CH ₂ );
The number of carbon atoms in the above-mentioned axial molecule (excluding the terminal functional group and the polymerizable unsaturated group-containing group) is 8 (one methylene group, six hexylene groups, and one carbonyl group), and therefore it corresponds to the above-mentioned specific rotaxane.

<Comparative rotaxane>
A rotaxane was synthesized according to the same procedure as for the specific rotaxane described above, except that 12-amino-1-dodecanol was used instead of 6-amino-1-hexanol. The resulting rotaxane is also referred to as the comparative rotaxane (comparative RC).

The obtained rotaxane is a rotaxane having a cyclic molecule (compound 3) and an axis molecule passing through the cyclic molecule,
the axis molecule has bulky terminal functional groups (dimethylphenyl groups) at both ends thereof to prevent the cyclic molecule from being detached,
the cyclic molecule has a polymerizable unsaturated group (methacryloyloxy group)-containing group,
The axial molecule has a polymerizable unsaturated group (methacryloyloxy group)-containing group (-C(=O)NHC ₂ H ₄ OC(=O)C(CH ₃ )=CH ₂ ),
The number of carbon atoms in the above-mentioned axial molecule (excluding the terminal functional group and the polymerizable unsaturated group-containing group) is 14 (one methylene group, 12 dodecylene groups, and one carbonyl group), and therefore it does not fall under the category of the above-mentioned specific rotaxane.

[Synthesis of polymeric particles]
A mixed solution of monomers (water: 36 g, surfactant (sodium dodecylbenzenesulfonate): 0.1 g, hydrophobe (hexadecane): 0.46 g, total monomer concentration: 1600 mM) in the ratios [mol %] shown in Table 1 below was emulsified by ultrasonic irradiation (375 W, 3 minutes) using an ultrasonic homogenizer, and then an initiator (potassium persulfate) (0.1 g) was added to the resulting emulsion and a polymerization reaction was carried out at 70°C for 4 hours (stirring speed: 200 rpm (rotations per minute)) to obtain each polymer microparticle.

The abbreviations for the monomers in Table 1 below are as follows:
EA: Ethyl acrylate, MEA: 2-methoxyethyl acrylate, MMA: Methyl methacrylate, HDD: 1,6-hexanediol dimethacrylate (chemical cross-linking agent)
RC: specific rotaxane (RC) synthesized as described above
Comparative RC: Comparative rotaxane (Comparative RC) synthesized as described above

〔evaluation〕

<Fracture energy, elongation at break, and stress at break>
Each polymer microparticle dispersion (5% by mass, 7 mL) (centrifugally purified and dialyzed) was used to prepare a 5 cm square film (approximately 0.4 mm thick). Four 1 cm x 4 cm films were cut from the obtained film, and a 2 mm cut was made in the center of the longitudinal direction using a diamond cutter. In this way, test specimens for tensile testing were prepared.
The obtained test pieces were subjected to a tensile test using a Tensilon tensile tester (load cell: 50 N, elongation rate: 10 mm/min, test temperature: 25°C) to evaluate the fracture energy, fracture elongation, and fracture stress. The results are shown in Table 1. The greater the fracture energy, fracture elongation, and fracture stress, the better. It can be said that the greater the fracture energy, the more excellent the toughness.

<Residual strain>
A stress of 100 kPa was applied to the film prepared as described above for 10 hours, and then the film was allowed to relax for 14 hours, after which the residual strain was measured. The larger the residual strain, the better the toughness against brittle fracture. The residual strain is preferably more than 25%. It is believed that a residual strain of more than 25% further suppresses the rate of crack propagation in the rubber material.

In Table 1, D _h (water), D _h (DMF) and the degree of swelling are as described above.

As can be seen from Table 1, compared with Comparative Example 1, which is a polymeric microparticle synthesized without using a rotaxane, and Comparative Examples 2 to 4, which are polymeric microparticles synthesized using an HDD instead of a rotaxane, Examples 1 to 3, which are polymeric microparticles synthesized using a specific rotaxane, exhibited large fracture energy and excellent toughness. Furthermore, a comparison between Example 2, which is a polymeric microparticle synthesized using a specific rotaxane, and Comparative Example 5, which is a polymeric microparticle synthesized using a rotaxane other than the specific rotaxane as the rotaxane (comparison between embodiments in which the rotaxane content relative to the (meth)acrylate is 0.05 mol%) shows that Example 2, which is a polymeric microparticle synthesized using a specific rotaxane, exhibited excellent mechanical properties (fracture energy, elongation at break, and stress at break).
Comparing Examples 1 to 3, Examples 1 and 2, in which the ratio of the specific rotaxane to the (meth)acrylate was 0.01 to 0.15 mol%, exhibited better mechanical properties (fracture energy, elongation at break, and stress at break). Among them, Example 2, in which the ratio of the specific rotaxane to the (meth)acrylate was 0.04 to 0.1 mol%, exhibited even better mechanical properties (fracture energy, elongation at break, and stress at break).

Similarly, compared to Comparative Example 6, which is a polymer microparticle synthesized using a rotaxane other than the specific rotaxane, Example 4, which is a polymer microparticle synthesized using the specific rotaxane, exhibited a large fracture energy and excellent toughness.

Similarly, compared with Comparative Example 7, which is a polymeric microparticle synthesized without using a rotaxane, Comparative Examples 8 to 10, which are polymeric microparticles synthesized using an HDD instead of a rotaxane, and Comparative Example 11, which is a polymeric microparticle synthesized using a rotaxane other than the specific rotaxane as the rotaxane, Examples 5 to 7, which are polymeric microparticles synthesized using the specific rotaxane, had a large fracture energy and exhibited excellent toughness.
Comparing Examples 5 to 7, Examples 5 and 6, in which the ratio of the specific rotaxane to the (meth)acrylate was 0.01 to 0.15 mol%, exhibited better mechanical properties (fracture energy, elongation at break, and stress at break). Among them, Example 6, in which the ratio of the specific rotaxane to the (meth)acrylate was 0.04 to 0.1 mol%, exhibited even better mechanical properties (fracture energy, elongation at break, and stress at break).

Claims (6)

A polymeric microparticle comprising a copolymer of a rotaxane having a cyclic molecule and an axis molecule passing through the cyclic molecule, and a (meth)acrylate,
both the cyclic molecule and the axis molecule have a polymerizable unsaturated group-containing group,
the carbon number of the axis molecule is 4 to 12,
The polymeric fine particles have a ratio of the rotaxane to the (meth)acrylate of 0.001 to 0.20 mol %.
However, the number of carbon atoms in the axis molecule refers to the number of carbon atoms in the axis-shaped portion of the axis molecule, and does not include the number of carbon atoms in the terminal functional group of the axis molecule and the number of carbon atoms in the substituent of the axis molecule. The polymeric microparticles according to claim 1, wherein two or more types of (meth)acrylates are used in combination as the (meth)acrylate. 3. The polymeric microparticles according to claim 1, which have a swelling degree of 18 or more. 4. The polymeric microparticle according to claim 1 , wherein the polymerizable unsaturated group of the polymerizable unsaturated group-containing group is a vinyl group, an acrylic group, or a methacrylic group. The polymeric microparticles according to any one of claims 1 to 4 , having an elongation at break of more than 400%. The polymeric microparticles according to any one of claims 1 to 5 , having a residual strain of more than 25%.