Hollow particles and their applications

Abstract

The subject of this invention is to provide a hollow particle capable of suppressing the aggregation of hollow particles in a dispersion medium and preventing the collapse of the hollow portion due to deformation, and its use therein. Specifically, the invention provides a hollow particle having a shell and a hollow portion surrounded by the shell, the hollow particle having an esterified surface.

Description

Technical Field

[0001] This invention relates to hollow particles and their uses.

[0002] Prior Technology

[0003] In the past, particles with internal pores were used as microcapsule particles to store the various substances contained within those pores.

[0004] Particles with internal gaps are called hollow particles and are used as light scattering materials, low-reflection materials, heat insulation materials, and low dielectric constant materials.

[0005] For example, Patent Document 1 and Patent Document 2 describe hollow particles obtained by polymerizing oil droplets containing a free radical reactive monomer and a hydrophobic organic solvent with low polymer compatibility with the monomer in an aqueous solution.

[0006] In addition, Patent Document 3 describes hollow organic-inorganic mixed microparticles with an organic and inorganic framework, a single-pore structure, an average particle size of 10 to 100 nm, a refractive index of less than 1.40, and surface-treated with a silane coupling agent.

[0007] Previous technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-80503

[0010] Patent Document 2: Japanese Patent Application Publication No. 2005-215315

[0011] Patent Document 3: Japanese Patent Application Publication No. 2009-242475 Summary of the Invention

[0012] The problem the invention aims to solve

[0013] The hollow particles described in patent documents 1 and 2 are prone to agglomeration in the dispersion medium because they have not undergone surface treatment.

[0014] Although the hollow particles described in Patent Document 3 are surface-treated with a silane coupling agent, they cannot maintain dispersion in a highly hydrophobic dispersion medium and instead aggregate.

[0015] In view of the above, the present invention aims to provide hollow particles that can suppress the agglomeration of hollow particles in a dispersion medium and prevent the collapse of the hollow portion due to deformation, and the use thereof.

[0016] Methods for solving problems

[0017] The inventors of this invention, through repeated research to achieve the aforementioned objectives, successfully developed the desired hollow particle and discovered that using this hollow particle could achieve the above objectives. This invention was completed based on such repeated research.

[0018] This invention discloses the following aspects of the invention.

[0019] Item 1. A hollow particle having a shell and a hollow portion surrounded by the shell, said hollow particle having an esterified surface.

[0020] Item 2. The hollow particle as described in Item 1, wherein the hollow particle has a surface treated with esterification by a phosphate compound.

[0021] Item 3. Hollow particles as described in Item 2, wherein the phosphate ester compound is a compound represented by the following formula (1).

[0022]

[0023] (In Formula 1, R1 represents a straight-chain or branched alkyl group with 3 to 19 carbon atoms, a straight-chain or branched alkoxy group with 3 to 19 carbon atoms, an allyl group, a (meth)acryloyl group, a (meth)acryloyloxy group, or a styryl group.)

[0024] R2 represents a hydrogen atom or a methyl group.

[0025] m represents a number greater than 0 and less than 30.

[0026] (n represents 1 or 2.)

[0027] Item 4. The hollow particle as described in any one of items 1 to 3, wherein,

[0028] The shell contains (meth)acrylic resin,

[0029] The (meth)acrylic resin contains polymers derived from (meth)acrylic reactive monomers having epoxy groups and / or polymers derived from (meth)acrylic reactive monomers having oxybutyl groups.

[0030] Item 5. The hollow particle as described in any one of Items 1 to 4, wherein the ratio η (absorbance ratio η: A1100 / A1720) of the infrared absorption spectrum obtained by measuring the hollow particle by ATR-FTIR is 0.800 or more and 2.000 or less.

[0031] Item 6. The hollow particle as described in any one of items 1 to 5, wherein the shell contains an inorganic component.

[0032] Item 7. Hollow particles as described in any one of items 1 to 6, wherein the average particle size is 10 to 200 nm.

[0033] Item 8. The hollow particle as described in any one of items 1 to 7, wherein the hollowness is 31.0 to 70.0% of the volume.

[0034] Item 9. A dispersion comprising hollow particles as described in any one of items 1 to 8.

[0035] Item 10. A coating agent comprising hollow particles as described in any one of items 1 to 8.

[0036] Item 11. A heat insulation film comprising hollow particles as described in any one of items 1 to 8.

[0037] Item 12. An antireflective film comprising hollow particles as described in any one of items 1 to 8.

[0038] Item 13. A light extraction membrane comprising hollow particles as described in any one of items 1 to 8.

[0039] Item 14. A low dielectric constant film comprising hollow particles as described in any one of items 1 to 8.

[0040] Item 15. A photosensitive resin composition comprising hollow particles as described in any one of items 1 to 8.

[0041] Effects of the invention

[0042] The hollow particles of this invention can suppress the aggregation of hollow particles in a dispersion medium and prevent the collapse of the hollow portion due to deformation. Because of these superior properties, the hollow particles of this invention are suitable for a wide range of applications, including dispersions, heat-insulating films, anti-reflective films, light extraction films, low-dielectric-constant films, and photosensitive resin compositions.

[0043] Implementation

[0044] The following provides a detailed description of the applicable embodiments of the present invention. The description of the constituent elements described below is based on representative embodiments and specific examples, and the present invention is not limited to these embodiments.

[0045] In this specification, the terms "contains" and "includes" include the concepts of "containing", "comprises", "substantially constitutes", and "consisting solely of".

[0046] In this specification, the upper or lower limit of a numerical range described in stages can be arbitrarily combined with the upper or lower limits of numerical ranges in other stages. Furthermore, the upper or lower limit of the numerical range described in this specification can be replaced by the values ​​shown in the embodiments or values ​​that can be explicitly derived from the embodiments. Additionally, in this specification, the values ​​before and after the word "to" encompass the range of upper or lower limits.

[0047] In this specification, "A and / or B" means "one of A and B" or "both of A and B", specifically, it means "A", "B", or "A and B".

[0048] In this instruction manual, room temperature refers to a temperature in the range of 20°C to 25°C.

[0049] In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylate" means acrylate or methacrylate.

[0050] In this specification, "(meth)acryloyl" means acryloyl "CH2=CHC(=O)-" or methacryloyl "CH2=C(CH3)-C(=O)-". In this specification, "(meth)acryloyloxy" means acryloyloxy "CH2=CHC(=O)O-" or methacryloyloxy "CH2=C(CH3)C(=O)O-".

[0051] In this specification, "polymer from monomer A" means a polymer containing constituent units from monomer A.

[0052] 1. Hollow particles

[0053] The hollow particles of the present invention have the following configurations (1) and (2):

[0054] (1) A hollow particle has a shell and a hollow part surrounded by the shell.

[0055] (2) Hollow particles have surfaces that have been esterified.

[0056] Because the hollow particles of the present invention possess the above-described structures (1) and (2), they can suppress the aggregation of hollow particles in the dispersion medium and prevent the collapse of the hollow portion due to deformation. Here, "preventing the collapse of the hollow portion due to deformation" means that the hollow particles can maintain a spherical shape.

[0057] The hollow particles of the present invention preferably have a surface treated with esterification by a phosphate compound.

[0058] As one implementation, the hollow particles preferably have their outer surface treated with a phosphate compound for esterification.

[0059] As one implementation, the hollow particle has a shell and a hollow portion surrounded by the shell, preferably with a phosphate ester compound attached to the surface of the shell.

[0060] As one implementation, the hollow particle has a shell and a hollow portion surrounded by the shell, the shell preferably having at least a portion of its outer surface covered with a phosphate ester compound.

[0061] As one implementation, the hollow particle has a shell and a hollow portion surrounded by the shell, and more preferably, at least a portion of the outer surface of the shell is coated with a phosphate ester compound.

[0062] As one implementation, the hollow particle has a shell and a hollow portion surrounded by the shell, and more preferably, at least a portion of the outer surface of the shell is covered with a layer made of a phosphate ester compound.

[0063] As one implementation, the outer surface of the shell being completely covered by phosphate ester compounds means that the outer surface of the shell is 100% covered by phosphate ester compounds.

[0064] As one implementation, the fact that a portion of the outer surface of the shell is covered with a phosphate compound means that the outer surface of the shell is typically more than 1% but less than 100% covered with a phosphate compound.

[0065] As one implementation, it is preferable that the phosphate ester compound is attached to the outer surface of the shell via electrostatic interaction, van der Waals forces, chemical bonds, etc. The chemical bonds are not particularly limited, and can be listed as covalent bonds, ionic bonds, coordination bonds, chelate bonds, hydrogen bonds, etc.

[0066] As one implementation, it is more preferable that the phosphate ester compound is attached to the outer surface of the shell via electrostatic interaction.

[0067] As one implementation, it is preferable that the phosphate compound is attached to the outer surface of the shell via an esterification reaction, and more preferably that the phosphate compound is attached via electrostatic interaction and also via an esterification reaction.

[0068] As one implementation, it is preferable that the outer surface of the shell has a phosphate ester compound attached via an esterification reaction, and more preferably a phosphate ester compound attached via an esterification reaction and electrostatic interaction.

[0069] As one implementation, it is preferable that a portion of the outer surface of the shell is coated with a phosphate ester compound via electrostatic interactions, van der Waals forces, or chemical bonds. Here, chemical bonds are not particularly limited and can include, for example, covalent bonds, ionic bonds, coordinate bonds, chelate bonds, and hydrogen bonds.

[0070] As one implementation, it is preferable that a portion of the outer surface of the shell is coated with a phosphate ester compound via electrostatic interaction.

[0071] As one implementation, it is preferable that at least a portion of the outer surface of the shell is chemically coated with a phosphate compound via an esterification reaction, and more preferably that the phosphate compound is coated via electrostatic interaction and chemically coated via an esterification reaction.

[0072] As one embodiment, the mass ratio of hollow particles to phosphate ester compound (mass of hollow particles: mass of phosphate ester compound) is preferably 100:1 to 100:1000, more preferably 100:20 to 100:100, even more preferably 100:26 to 100:75, still more preferably 100:26.5 to 100:50, and particularly preferably 100:27 to 100:40. A specific method for determining this mass ratio (mass of hollow particles: mass of phosphate ester compound) is described in the examples described later.

[0073] In this embodiment, the phosphate ester compound is preferably a compound represented by the following formula (1).

[0074]

[0075] (In formula (1), R1 is a straight-chain or branched alkyl group with 3 to 19 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19), a straight-chain or branched alkoxy group with 3 to 19 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19), an allyl (CH2=CHCH2-), (meth)acryloyl, (meth)acryloyloxy, or styryl (vinylphenyl).

[0076] R2 represents a hydrogen atom or a methyl group.

[0077] m represents a number between 0 and 30.

[0078] (n represents 1 or 2.)

[0079] In the above formula (1), m is the additional molar number of oxyethylene (-CH2CH2O-). In other words, m is a numerical value within the necessary range of 0 to 30 additional molar numbers when the total number of compounds shown in formula (1) is 1 mole.

[0080] In the above formula (1), m is preferably 1 or more and 25 or less, more preferably 5 or more and 20 or less, and even more preferably 8 or more and 15 or less.

[0081] In the above formula (1), R2 is preferably a hydrogen atom.

[0082] In the above formula (1), straight-chain or branched alkyl groups with 3 to 19 carbon atoms can be listed as follows: n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, etc.

[0083] In the above formula (1), straight-chain or branched alkoxy groups with 3 to 19 carbon atoms can be listed as follows: n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, n-hexoxy, cyclohexoxy, n-heptoxy, n-octoxy, 2-ethylhexoxy, tert-octoxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecanyloxy, n-hexadecyloxy, n-heptadecyloxy, n-octadecyloxy, n-nonadecanyloxy, etc.

[0084] In formula (1) above, R1 is preferably a straight-chain or branched alkyl group having 3 to 19 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19), or a straight-chain or branched alkoxy group having 3 to 19 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19).

[0085] More preferably, it is a straight-chain or branched alkyl group having 10 to 19 carbon atoms (10, 11, 12, 13, 14, 15, 16, 17, 18 or 19), or a straight-chain or branched alkoxy group having 10 to 19 carbon atoms (10, 11, 12, 13, 14, 15, 16, 17, 18 or 19).

[0086] More preferably, it is a straight-chain or branched alkyl group or a straight-chain or branched alkoxy group having 13 carbon atoms.

[0087] Particularly preferred are straight-chain alkyl or straight-chain alkoxy groups having 13 carbon atoms.

[0088] The preferred option is a straight-chain alkyl group with 13 carbon atoms.

[0089] As an implementation, phosphate ester compounds can be widely used from well-known commercially available products. Examples of commercially available products include: Phosphhanol ML-200, Phosphhanol BH-650, Phosphhanol ED-200, Phosphhanol RA-600, Phosphhanol ML-220, Phosphhanol ML-240, Phosphhanol RD-510Y, Phosphhanol RS-410, Phosphhanol RS-610, Phosphhanol RS-710, Phosphhanol RL-210, Phosphhanol RL-310, Phosphhanol RB-410, Phosphhanol RP-710, and Phosphhanol CP-120 (all manufactured by Toho Chemical Industry Co., Ltd.). These commercially available products can be used individually or in combination of two or more.

[0090] In this embodiment, the shell is preferably a (meth)acrylic resin containing a polymer derived from a (meth)acrylic reactive monomer having an epoxy group and / or a polymer derived from a (meth)acrylic reactive monomer having an oxybutyl group.

[0091] In this embodiment, the (meth)acrylic resin is preferably a polymer containing reactive monomers derived from (meth)acrylic acid, and more preferably a polymer containing both reactive monomers derived from (meth)acrylic acid and crosslinking monomers.

[0092] The (meth)acrylic resin is preferably a polymer containing a (meth)acrylic reactive monomer having an epoxy group and / or a (meth)acrylic reactive monomer having an oxybutyl group, and more preferably a polymer containing a (meth)acrylic reactive monomer having an epoxy group.

[0093] Epoxy groups and cyclobutane groups are functional groups that react with compounds having amino, carboxyl, sulfone, mercapto, hydroxyl, or isocyanate groups to form polymers.

[0094] Since (meth)acrylic reactive monomers have epoxy groups or cyclobutane groups, polymers with cross-linked structures (cross-linked polymers) can be manufactured by free radical polymerization of (meth)acrylic reactive monomers with epoxy groups or cyclobutane groups, followed by reaction of the epoxy groups or cyclobutane groups with cross-linking monomers.

[0095] (Meth)acrylic acid reactive monomers typically possess a (meth)acrylic acid reactive functional group. Examples of such (meth)acrylic acid reactive monomers include esters of (meth)acrylic acid with alcohols having 1 to 25 carbon atoms.

[0096] Esters of (meth)acrylic acid with alcohols having 1 to 25 carbon atoms include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, isooctyl methacrylate, n-nonyl methacrylate, isodecyl methacrylate, norborneol methacrylate, isoborneol methacrylate, adamantane methacrylate, lauryl methacrylate, tetradecyl methacrylate, isostearyl methacrylate, phenoxyethylene glycol mono(meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-ethylhexyl methacrylate, etc. These esters can be used individually or in combination of two or more.

[0097] The (meth)acrylic reactive monomers are preferably monomers having (meth)acrylic reactive functional groups and non-(meth)acrylic reactive functional groups.

[0098] Monomers with reactive (meth)acrylic acid groups and non-(meth)acrylic acid groups can be polymerized based on either of these two functional groups to produce polymer particles. The remaining functional group in these polymer particles reacts with a crosslinking monomer, thereby transforming these polymer particles into polymers with crosslinked structures (crosslinked polymers).

[0099] The (meth)acrylic reactive monomer is preferably a (meth)acrylic reactive monomer having an epoxy group or a (meth)acrylic reactive monomer having an oxycyclobutane group, and more preferably a (meth)acrylic reactive monomer having an epoxy group.

[0100] Examples of reactive monomers of (meth)acrylic acid with epoxy groups or with oxybutyl groups include glycidyl methacrylate, 4-hydroxybutyl methacrylate glycidyl ether, 3-ethyloxetane-3-ylmethyl methacrylate, and 3,4-epoxycyclohexyl methacrylate. These monomers can be used alone or in combination of two or more. Furthermore, the term "glycidyl methacrylate" refers specifically to glycidyl methacrylate (glycidyl methacrylate) and glycidyl acrylate (glycidyl acrylate).

[0101] In this embodiment, the ratio η (absorbance ratio η: absorbance A1100 / A1720) of the infrared spectrum obtained by ATR-FTIR measurement of hollow particles is preferably 0.800 or more and 2.000 or less, more preferably 0.810 or more and 1.750 or less, particularly preferably 0.820 or more and 1.500 or less, and even more preferably 0.825 or more and 1.250 or less.

[0102] As one implementation, the lower limit of the absorbance ratio η (A1100 / A1720) can be 0.800, 0.805, 0.810, 0.815, 0.820, 0.825 and 0.830, and the upper limit of the absorbance ratio η (A1100 / A1720) can be 2.000, 1.900, 1.800, 1.700, 1.600, 1.500, 1.400, 1.300, 1.200, 1.100 and 1.000, and these upper and lower limits can be combined arbitrarily.

[0103] The specific method for determining the absorbance ratio η (A1100 / A1720) is described in the examples described later.

[0104] In this embodiment, it is preferable that the shell contains inorganic components.

[0105] As one embodiment, the shell contains a (meth)acrylic resin, which is preferably a polymer containing a (meth)acrylic monomer having an epoxy group, a polymer containing a (meth)acrylic monomer having an oxybutyl group, or a polymer containing a (meth)acrylic reactive monomer having a silicon group.

[0106] As one embodiment, the shell contains a (meth)acrylic resin, more preferably a polymer derived from a (meth)acrylic monomer having an epoxy group, a polymer derived from a (meth)acrylic monomer having an oxybutyl group, a polymer derived from a (meth)acrylic reactive monomer having a silicon group, or a polymer derived from a crosslinking monomer containing a nitrogen atom.

[0107] As one embodiment, the shell contains (meth)acrylic resin, more preferably a polymer derived from (meth)acrylic monomers having an epoxy group or from (meth)acrylic monomers having an oxybutyl group, a polymer derived from (meth)acrylic reactive monomers having a silicon group, and a polymer derived from an amine compound (a polymer derived from a constituent unit containing an amine compound).

[0108] As an implementation aspect, examples of silicon-based (meth)acrylic acid reactive monomers include: 3-methacryloyloxypropyl dimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, 3-methacryloyloxypropyl methyldiethoxysilane, 3-methacryloyloxypropyl triethoxysilane, 3-propenoxypropyl trimethoxysilane, etc. These monomers can be used individually or in combination of two or more.

[0109] As one aspect of implementation, the amine compound is preferably an aliphatic amine compound and / or a heterocyclic amine compound, more preferably an aliphatic amine compound.

[0110] Examples of the aforementioned aliphatic amine compounds include: ethylenediamine, N,N,N',N'-tetramethylethylenediamine, propylenediamine, N,N,N',N'-tetramethylpropylenediamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, diethylenetriamine, N,N,N',N",N"-pentamethyldiethylenetriamine, triethylenetetramine, tetraethylenepentamine, 3,3'-diaminodipropylamine, butanediamine, pentanediamine, hexamethylenediamine, trimethylhexamethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl) ether, 2-[2-(dimethylamino)ethoxy]ethanol, triethanolamine, dimethylaminohexanol, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxospiro(5,5)undecane adduct, etc. These aliphatic amine compounds can be used individually or in combination of two or more.

[0111] As an implementation aspect, the aliphatic amine compound is preferably ethylenediamine.

[0112] Examples of heterocyclic amine compounds include: pyrrolidine, piperidine, piperazine, N-methylpiperazine, N,N'-dimethylpiperazine, N-aminoethylpiperazine, N,N',N'-trimethylaminoethylpiperazine, morpholine, methylmorpholine, ethylmorpholine, quinine ring (1-azabicyclo[2.2.2]octane), triethylenediamine (1,4-diazabicyclo[2.2.2]octane), pyrrole, pyrazole, pyridine, hexahydro-1,3,5-tris(3-dimethylaminopropyl)-1,3,5- Triazine, 1,8-diazabicyclo[5.4.0]-7-undecene, imidazole, 1-methylimidazolium, 2-methylimidazolium, 3-methylimidazolium, 4-methylimidazolium, 5-methylimidazolium, 1-ethylimidazolium, 2-ethylimidazolium, 3-ethylimidazolium, 4-ethylimidazolium, 5-ethylimidazolium, 1-n-propylimidazolium, 2-n-propylimidazolium, 1-isopropylimidazolium, 2-isopropylimidazolium, 1-n-butylimidazolium, 2-n-butylimidazolium, 1-isobutylimidazolium, 2-isobutylimidazolium, 2-Undecyl-1H-imidazolium, 2-Heptadecyl-1H-imidazolium, 1,2-Dimethylimidazolium, 1,3-Dimethylimidazolium, 2,4-Dimethylimidazolium, 2-Ethyl-4-methylimidazolium, 1-Phenylideneimidazolium, 2-Phenylidene-1H-imidazolium, 4-Methyl-2-phenyl-1H-imidazolium, 2-Phenylidene-4-methylimidazolium, 1-Benzyl-2-methylimidazolium, 1-Benzyl-2-phenylimidazolium, 1-Cyanoethyl-2-methylimidazolium, 1-Cyanoethyl-2-ethyl-4 1-Methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-bis(2-cyanethoxy)methylimidazole, 1-dodecyl-2-methyl-3-benzylimidazole onium chloride, 1-benzyl-2-phenylimidazole hydrochloride, etc. These heterocyclic amine compounds can be used alone or in combination of two or more.

[0113] As an implementation aspect, the heterocyclic amine compound is preferably piperazine and N-aminoaminoethylpiperazine.

[0114] In this embodiment, the average particle size of the hollow particles is preferably 10 nm to 200 nm, more preferably 30 nm to 150 nm. When the average particle size of the hollow particles is 10 nm or more, the aggregation between the hollow particles can be further suppressed, and the operability is improved. When the average particle size of the hollow particles is 200 nm or less, when the hollow particles are mixed with the coating agent, resin, etc., the dispersion of surface unevenness or particle interface can be further suppressed.

[0115] In this specification, the term "average particle size of hollow particles" refers to the average particle size of the hollow particles contained in the hollow particle dispersion. The dispersion medium containing the hollow particle dispersion is applicable to the dispersion medium shown in the examples of <dispersions containing hollow particles> described later. A particularly preferred dispersion medium for hollow particle dispersions is propylene glycol monomethyl ether acetate.

[0116] The specific method for determining the average particle size of hollow particles is described in the examples described later.

[0117] In this embodiment, the lower limit of the average particle size of the hollow particles can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm and 80 nm, and the upper limit of the average particle size of the hollow particles can be 200 nm, 190 nm, 180 nm, 170 nm, 160 nm, 150 nm, 140 nm, 130 nm, 120 nm, 110 nm, 100 nm and 90 nm. These upper and lower limits can be combined arbitrarily.

[0118] In this embodiment, the hollowness of the hollow particles is preferably 31.0 to 70% of their volume.

[0119] In this specification, the term "hollow ratio of hollow particles" refers to the hollow ratio of the adhesive in the hollow particles, and the term "hollow ratio of the adhesive in the hollow particles" refers to the volume fraction (volume %) of air contained in the hollow particles in the adhesive.

[0120] Examples of such adhesives include fluorinated resins, polyamide resins, acrylic resins, polyurethane resins, polyurethane acrylate resins, and butyraldehyde resins. Among these, acrylic resins are preferred, more preferably acrylic resins containing carboxyl groups, and even more preferably liquid acrylic resins containing carboxyl groups. These adhesives can be used individually or in combination of two or more.

[0121] The specific method for determining the hollowness of the hollow particle adhesive is described in the examples described later.

[0122] In this embodiment, the lower limit of the hollow particle hollowness percentage can be 31.0% by volume, 31.5% by volume, 32.0% by volume, 32.5% by volume, 33.0% by volume, 33.5% by volume, 34.0% by volume, and 34.5% by volume. The upper limit of the hollow particle hollowness percentage can be 70% by volume, 65% by volume, 60% by volume, 55% by volume, 50% by volume, 45% by volume, and 40% by volume. These upper and lower limits can be combined arbitrarily.

[0123] As one embodiment, the shell is preferably composed of at least one or more layers. As one embodiment, when the shell is composed of at least one or more layers, the layers constituting the shell can be a single layer or multiple layers (e.g., two layers, three layers, four layers).

[0124] <Any additives>

[0125] The hollow particles of this invention may contain additives without diminishing the invention. Examples of additives include: pigment particles (pigments), dyes, stabilizers, ultraviolet absorbers, defoamers, thickeners, heat stabilizers, leveling agents, lubricants, antistatic agents, etc. These additives may be used individually or in combination of two or more.

[0126] The pigment particles used in this technical field are not particularly limited. Specific examples of pigment particles include: iron oxide pigments such as mica iron oxide and iron black; lead oxide pigments such as red lead and yellow lead; titanium dioxide pigments such as titanium white (rutile titanium dioxide), titanium yellow, and titanium black; cobalt oxide; zinc oxide pigments such as zinc yellow; and molybdenum oxide pigments such as molybdenum red and molybdenum white. Pigment particles can be used individually or in combination of two or more.

[0127] <Dispersion containing hollow particles>

[0128] The following examples illustrate aspects of dispersions containing the hollow particles of this embodiment.

[0129] In this embodiment, the dispersion contains a dispersion medium and hollow particles of this embodiment. The dispersion medium is not particularly limited as long as it is a liquid that does not completely dissolve the hollow particles of this embodiment.

[0130] Examples of the aforementioned dispersion media include: natural water, purified water, distilled water, ion-exchange water, pure water, etc.

[0131] Alcohol solvents such as methanol, ethanol, butanol, isobutanol, and n-propanol;

[0132] Ketone solvents such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and diacetone alcohol;

[0133] Diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether and other ethylene glycol ether solvents;

[0134] Ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and other ethylene glycol ester solvents;

[0135] Ether solvents such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, and triethylene glycol dimethyl ether;

[0136] Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, and butyl lactate;

[0137] Hydrocarbon solvents such as toluene, xylene, solvent oil, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane;

[0138] Halogen-based solvents such as chloromethane, dichloromethane, chloroform, and carbon tetrachloride; etc. These dispersion media can be used individually or in combination of two or more.

[0139] <Applications>

[0140] The hollow particles of this embodiment can be used as additives in masterbatches for forming coatings, paints, paper, information recording paper, light diffusion films (optical sheets), heat insulation films, thermoelectric conversion materials, light guide plate inks, anti-reflective films, light extraction films, photosensitive resin films, photosensitive resin compositions, light diffusion plates, light guide plates, etc.; or as additives in cosmetics.

[0141] <Coating Agent>

[0142] Examples of coatings containing hollow particles in this embodiment are as follows.

[0143] In this aspect, the coating agent contains the hollow particles of this embodiment. In addition to the hollow particles of this embodiment, the coating agent may also contain an adhesive.

[0144] The adhesives described above can be any commonly used adhesives in this field. Examples of adhesives include thermosetting resins and thermoplastic resins.

[0145] More specifically, adhesives include, for example, fluoropolymer resins, polyamide resins, acrylic resins, polyurethane resins, acrylate polyurethane resins, and butyraldehyde resins. These adhesives can be used individually or in combination of two or more.

[0146] The adhesive described above can be a single polymer of a reactive monomer or a copolymer of multiple monomers.

[0147] Reactive monomers that can be used in the above adhesives include, for example:

[0148] Monofunctional reactive monomers of methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, cyclohexyl methacrylate, heptyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isodecanyl methacrylate, norborneol methacrylate, isoborneol methacrylate, adamantane methacrylate, lauryl methacrylate, tetradecyl methacrylate, isostearyl methacrylate, isoborneol methacrylate, phenoxyethylene glycol methacrylate, phenoxydiethylene glycol methacrylate, 2-ethylhexyl methacrylate, etc., and esters of methacrylic acid and alcohols having 1 to 25 carbon atoms;

[0149] Trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyltetroxide tri(meth)acrylate (neopentyltetroxide triacrylate or neopentyltetroxide trimethacrylate), neopentyltetroxide tetra(meth)acrylate, bisnepentyltetroxide hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyltetroxide di(meth)acrylate, trimethylolpropane tri(meth)acrylate, bistrimethylolpropane tetra(meth)acrylate, bisnepentyltetroxide penta(meth)acrylate Multifunctional reactive monomers such as acrylates, trinepentylenetetrol octa(meth)acrylate, tetranepentylenetetrol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerol tetra(meth)acrylate, adamantyl di(meth)acrylate, isocamphenyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, and bis(trimethylolpropane tetra(meth)acrylate; etc.

[0150] Furthermore, when using these reactive monomers, polymerization initiators that initiate a hardening reaction via ionizing radiation can be used. Examples of polymerization initiators include: imidazole derivatives, diimidazole derivatives, N-arylglycine derivatives, organic azido compounds, titanocerocene, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, thioxanone derivatives, etc.

[0151] In addition, examples of adhesives include inorganic adhesives that use hydrolysates of silanols. Examples of silanols include: tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, allyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxytrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane. Propyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-propylisocyanatetrimethoxysilane, 3-propylisocyanatetriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-ureapropyltrimethoxysilane, 3-ureapropyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiethoxysilane.

[0152] Adhesives can be widely used from well-known commercially available products. Examples of commercially available products include: ARUFON UC-3510 (average molecular weight 2000) manufactured by Toa Synthetic Co., Ltd.; NK ESTER A-TMM-3LM-N manufactured by Shin-Nakamura Chemical Co., Ltd.; and DIANAL LR-102 and DIANAL BR-106 manufactured by Mitsubishi Rae Co., Ltd. These can be used individually or in combination of two or more.

[0153] In this aspect, when the coating agent contains an adhesive and hollow particles in this embodiment, the content of hollow particles in the coating agent is adjusted appropriately according to the application, and is typically 0.1 to 1000 parts by mass relative to 100 parts by mass of the adhesive.

[0154] Coating agents typically contain a dispersion medium. The dispersion medium can be either water-based or oil-based.

[0155] Examples of water-based media include: water, alcohol solvents, and ethylene glycol ether solvents.

[0156] The above-mentioned oily solvents include: hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as dioxane and ethylene glycol diethyl ether; ethylene glycol ester solvents such as ethylene glycol monoethyl ether acetate and propylene glycol monomethyl ether acetate; etc.

[0157] In addition to the hollow particles of this embodiment, the coating agent may also contain hardeners, colorants, antistatic agents, leveling agents, etc.

[0158] There are no particular restrictions on the substrate to which the coating agent is applied; the substrate can be used depending on the application. For example, transparent substrates such as glass substrates and transparent resin substrates can be used for optical applications.

[0159] <Masterbatch>

[0160] The following examples illustrate aspects containing hollow particles as described in this embodiment.

[0161] In this embodiment, the masterbatch contains the hollow particles of this embodiment. In addition to the hollow particles of this embodiment, the masterbatch may also contain a base resin.

[0162] The aforementioned base resin can be any of the well-known thermoplastic resins commonly used in this field. Examples of thermoplastic resins include: (meth)acrylic resins, alkyl (meth)acrylate-styrene copolymer resins, polycarbonate resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, etc. These thermoplastic resins can be used individually or in combination of two or more.

[0163] From the viewpoint of further improving transparency, the aforementioned substrate resin is preferably selected from at least one of the group consisting of (meth)acrylic resin, alkyl (meth)acrylic ester-styrene copolymer resin, polycarbonate resin and polyester resin.

[0164] The aforementioned base resin may contain trace amounts of additives such as ultraviolet absorbers, heat stabilizers, colorants, and fillers.

[0165] In this aspect, the masterbatch can be manufactured by extrusion molding, injection molding, or other molding methods after the base resin and the hollow particles of this embodiment are melt-mixed.

[0166] In this respect, the hollow particle content in the masterbatch is preferably 0.1 to 60% by mass, more preferably 0.3 to 30% by mass, and even more preferably 0.4 to 10% by mass.

[0167] In this process, the masterbatch is pressed into a molded body using methods such as extrusion molding or injection molding. Furthermore, a new base resin can be added during molding.

[0168] The amount of the aforementioned base resin added is preferably such that the content of hollow particles in the final molded article is 0.1 to 60% by mass.

[0169] During molding, additives such as ultraviolet absorbers, heat stabilizers, colorants, and fillers can be added in small amounts.

[0170] <Cosmetic Materials>

[0171] The following are examples of cosmetics containing hollow particles from this embodiment.

[0172] In this aspect, the cosmetic material contains the hollow particles of this embodiment. Examples of cosmetic materials in this aspect include: solid cosmetic materials such as loose powder and foundation; powder cosmetic materials such as baby powder and talcum powder; and liquid cosmetic materials such as lotion, emulsion, cream, foundation, moisturizer, and primer.

[0173] The proportion of hollow particles in cosmetics varies depending on the type of cosmetic.

[0174] In the case of solid cosmetics such as loose powder and foundation, the hollow particle content in the cosmetic is preferably 1 to 20% by mass, more preferably 3 to 15% by mass.

[0175] In the case of powder cosmetics such as baby powder, the hollow particle content in the cosmetic is preferably 1 to 20% by mass, more preferably 3 to 15% by mass.

[0176] In the case of liquid cosmetics such as toners, lotions, creams, foundations, moisturizers, and primers, the hollow particle content in the cosmetic is preferably 1 to 15% by mass, more preferably 3 to 10% by mass.

[0177] In this regard, the aforementioned cosmetics, as other ingredients, may contain inorganic compounds such as mica and talc, coloring pigments such as iron oxide, titanium dioxide, ultramarine, Prussian blue, and carbon black, or synthetic dyes such as azo dyes, in order to improve optical performance or feel.

[0178] When cosmetics are in liquid form, there are no particular restrictions on the liquid medium; water, alcohol, hydrocarbons, silicone oil, plant or animal fats, etc., can be used.

[0179] In this regard, in addition to the other ingredients mentioned above, the cosmetics can be supplemented with various functionalities by adding additives commonly used in cosmetics, such as moisturizers, anti-inflammatory agents, whitening agents, UV protectants, disinfectants, antiperspirants, cooling agents, and fragrances.

[0180] Anti-reflective coating

[0181] The following examples illustrate aspects of antireflective films containing hollow particles, which are part of this embodiment.

[0182] In this embodiment, the antireflective film contains hollow particles. Examples of antireflective films in this embodiment include: films, sheet-like objects, etc.

[0183] In this respect, films or sheet-like objects containing hollow particles can be used as anti-reflective films because the air layer in the hollow part of the hollow particles reduces the refractive index.

[0184] In this respect, the antireflective film can be obtained by applying the coating agent to the substrate by known methods such as dip coating, spraying, spin coating, rotational coating or roller coating, and drying it. It can also be obtained by heating, ultraviolet irradiation, firing or so as necessary.

[0185] <Light Extraction Membrane>

[0186] The following are examples of light extraction films containing hollow particles from this embodiment.

[0187] In this embodiment, the light extraction film contains hollow particles. In LEDs, OLED lighting, and similar applications, the large refractive index difference between the air layer and the light-emitting layer easily traps the emitted light within the module. Therefore, a light extraction film is used to improve luminous efficiency.

[0188] In this regard, light extraction films can be categorized as membranes, sheet-like objects, etc. Membranes or sheet-like objects containing hollow particles, due to the reduced refractive index caused by the air layer in the hollow particle layer, can be used as light extraction films.

[0189] In this respect, the aforementioned light extraction film can be obtained by coating the substrate with the aforementioned coating agent by known methods such as dip coating, spraying, spin coating, rotational coating or roller coating, and drying it. It can also be obtained by heating, ultraviolet irradiation, firing or so as necessary.

[0190] Heat insulation film

[0191] The following are examples of heat-insulating films containing hollow particles of this embodiment.

[0192] In this embodiment, the heat insulation film contains hollow particles. Examples of heat insulation films include: films and sheet-like objects.

[0193] In this aspect, the film or sheet containing the hollow particles of this embodiment can be used as a heat insulation film because the hollow portion of the hollow particles has an air layer. Furthermore, because the average particle size of the hollow particles is small, the aforementioned heat insulation film has high transparency. In addition, because adhesives have difficulty penetrating the hollow portion of the hollow particles, the aforementioned heat insulation film has high heat insulation properties.

[0194] In this respect, the heat insulation film can be obtained by applying the above-mentioned coating agent to the substrate by well-known methods such as dip coating, spraying, spin coating, rotational coating or roller coating, and drying it. It can also be obtained by heating, ultraviolet irradiation, firing or so as necessary.

[0195] Low dielectric constant films

[0196] The following examples illustrate aspects of low dielectric constant films containing hollow particles from this embodiment.

[0197] In this aspect, the low dielectric constant film contains the hollow particles of this embodiment. Examples of low dielectric constant films include: films and sheet-like objects.

[0198] In this aspect, the film or sheet-like object containing the hollow particles of this embodiment can be used as a low dielectric constant film because the hollow portion of the hollow particles has an air layer. Furthermore, because the hollow particles have a small average particle size, the aforementioned low dielectric constant film has high transparency.

[0199] In this respect, the low dielectric constant film can be obtained by coating the above-mentioned coating agent onto the substrate by well-known methods such as dip coating, spraying, spin coating, rotation coating or roller coating, and drying. It can also be obtained by heating, ultraviolet irradiation, firing or so as necessary.

[0200] <Photosensitive Resin Composition>

[0201] The following examples illustrate photosensitive resin compositions containing hollow particles of this embodiment.

[0202] In this aspect, the photosensitive resin composition contains the hollow particles of this embodiment. Because the hollow portion of the hollow particles has an air layer, the photosensitive resin composition containing these hollow particles has a low refractive index. Furthermore, because the average particle size of the hollow particles is small, the aforementioned photosensitive resin composition has high transparency.

[0203] In this respect, the photosensitive resin composition can be obtained by applying the above-mentioned coating agent to the substrate by well-known methods such as dip coating, spraying, spin coating, rotation coating or roller coating, and drying. It can also be obtained by heating, ultraviolet irradiation, firing or so as necessary.

[0204] 2. Methods for manufacturing hollow particles

[0205] Hollow particles in this embodiment can typically be manufactured by surface-treating hollow particles in a hollow particle dispersion with a phosphate ester compound.

[0206] The method for manufacturing hollow particles according to this embodiment is described in detail below. The step of surface treating the hollow particles with a phosphate ester compound may also be described hereby simply as the "surface treatment step".

[0207] Unless otherwise specified, the details of the phosphate ester compound in the surface treatment steps are the same as those described in "1. Hollow Particles".

[0208] In the surface treatment step, the amount of phosphate ester compound used is preferably 10 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of hollow particles.

[0209] In the surface treatment steps, it is preferable to perform the following steps (1), (2), (3) and (4) in that order.

[0210] Step (1): Dissolve the phosphate compound in an organic solvent in a container.

[0211] Step (2): Add hollow particle dispersion and stir at room temperature to prepare slurry.

[0212] Step (3): Add the prepared slurry to an evaporator or the like, and remove the dispersion medium of the hollow particle dispersion and the organic solvent from step (1) from the slurry by vacuum distillation in a water bath or the like.

[0213] Step (4): Add organic solvent and perform solvent replacement in an evaporator to prepare a dispersion of hollow particles with phosphate ester compound surface treatment.

[0214] In step (1) above, the organic solvents can be listed as follows:

[0215] Lower alcohols such as methanol, ethanol, 1-propanol (n-propanol), 2-propanol (isopropanol), 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol;

[0216] Hydrocarbon solvents such as toluene, xylene, hexane, and cyclohexane;

[0217] Ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone;

[0218] Ester solvents such as ethyl acetate, methyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, and tert-butyl acetate;

[0219] Isopropyl ether, tetrahydrofuran, and other ether solvents;

[0220] Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and other ethylene glycol-based solvents;

[0221] Diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and other ethylene glycol-based solvents;

[0222] Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; etc. These organic solvents can be used individually or in combination of two or more.

[0223] In step (1) above, the phosphate ester compound is as described in “1. Hollow Particles” above.

[0224] In step (1) above, the amount of organic solvent used is preferably 500 parts by mass or more and 4000 parts by mass or less relative to 100 parts by mass of the phosphate ester compound, and more preferably 1000 parts by mass or more and 3500 parts by mass or less.

[0225] The method for manufacturing the hollow particle dispersion used in step (2) above will be described in the following section, "Method for Manufacturing Hollow Particle Dispersion".

[0226] In step (3) above, the temperature during vacuum distillation is preferably above 30°C and below 200°C.

[0227] In step (4) above, the temperature at which solvent replacement is performed is preferably above 30°C and below 200°C.

[0228] In step (4) above, the organic solvents can be listed as follows:

[0229] Lower alcohols such as methanol, ethanol, 1-propanol (n-propanol), 2-propanol (isopropanol), 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol;

[0230] Hydrocarbon solvents such as toluene, xylene, hexane, and cyclohexane;

[0231] Ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone;

[0232] Ester solvents such as ethyl acetate, methyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, and tert-butyl acetate;

[0233] Isopropyl ether, tetrahydrofuran, and other ether solvents;

[0234] Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and other ethylene glycol-based solvents;

[0235] Diethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and other ethylene glycol-based solvents;

[0236] Amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; etc. These organic solvents can be used individually or in combination of two or more.

[0237] <Method for manufacturing hollow particle dispersions>

[0238] Hollow particle dispersions can be manufactured via steps such as: a manufacturing step (polymerization step) to produce polymer particles containing a non-reactive solvent, a step to separate the non-reactive solvent phase from the polymer particles (phase separation step), a step to remove the non-reactive solvent as necessary (solvent removal step), and a step to disperse it in a medium (dispersion step).

[0239] Methods for manufacturing hollow particle dispersions can simultaneously carry out polymerization and phase separation steps of reactive monomer reactions, or can involve forming polymer particles before phase separation in the non-reactive solvent, followed by phase separation. The method of forming polymer particles first and then initiating phase separation is preferable because it suppresses pinhole formation and improves monodispersity.

[0240] In a method where polymer particles are formed before phase separation in a non-reactive solvent, polymer particles are produced by polymerizing reactive monomers having (meth)acrylic acid reactive functional groups and non-(meth)acrylic acid reactive functional groups, based on one of the two functional groups.

[0241] Non-reactive solvents can be mixed with reactive monomers first, or absorbed after the polymer particles are made, and thus contained in the polymer particles.

[0242] Next, through the polymerization of the residual functional groups among the two functional groups, the polymer and the non-reactive solvent phase separate, thereby obtaining microcapsule particles containing the non-reactive solvent. Afterwards, the non-reactive solvent is removed to obtain hollow particles.

[0243] As described above, by separating the polymerization step from the phase separation step, the following is achieved:

[0244] • The voids between polymers in the shell, present in previous manufacturing methods, are no longer present, thus suppressing the formation of pinholes in the resulting hollow particle shells; and

[0245] • The shape of microcapsule particles or hollow particles does not depend on oil droplets, but on the shape or particle size distribution of polymer particles before phase separation, making it easier to obtain microcapsule particles or hollow particles with high monodispersity.

[0246] The advantages are described below, along with an explanation of the manufacturing method.

[0247] (A) Aggregation step

[0248] The polymerization step involves polymerizing reactive monomers having (meth)acrylic acid reactive functional groups and non-(meth)acrylic acid reactive functional groups, based on either of the two functional groups, to produce polymer particles. Non-reactive solvents are either mixed with the reactive monomers beforehand or absorbed after the polymer particles are produced, and are thus contained within the polymer particles.

[0249] (a) Method for preparing polymer particles

[0250] As a method for producing polymer particles, any known method can be used, such as bulk polymerization, liquid polymerization, dispersion polymerization, suspension polymerization, and emulsion polymerization. Among these, suspension polymerization or emulsion polymerization, which is relatively simple to produce, is preferred. Furthermore, emulsion polymerization, which can more easily obtain polymer particles with high monodispersity, is even more preferred.

[0251] <Polymerization Initiator>

[0252] When performing polymerization, it is preferable to add a compound that reacts with the functional group that is the target of the polymerization reaction. This compound can be used as a polymerization initiator when polymerizing the reactive functional group of (meth)acrylic acid.

[0253] Polymerization initiators can be listed as: ammonium persulfate (ammonium perdisulfate), potassium persulfate, sodium persulfate, and other persulfates;

[0254] Organic peroxides include cumene hydroperoxide, di-tert-butyl peroxide, dicumene peroxide, benzoyl peroxide, lauroyl peroxide, dimethyl bis(tert-butylperoxy)hexane, dimethyl bis(tert-butylperoxy)hexyn-3, bis(tert-butylperoxyisopropyl)benzene, bis(tert-butylperoxy)trimethylcyclohexane, butyl bis(tert-butylperoxy)valerate, 2-ethylhexane peroxytert-butyl ester, benzoyl peroxide, p-menthane hydroperoxide, and tert-butyl peroxybenzoate, etc.

[0255] 2,2-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2-Azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2-Azobis(2-amidinylpropane) dihydrochloride, 2,2-Azobis[N-(2-carboxyethyl)-2-methylpropamidin] hydrate, 2,2-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride, 2,2-Azobis[2-(2-imidazolin-2-yl)propane], 2,2-Azobis(1-iminoyl)propane 1-Pyrrolidinyl-2-ethylpropane) dihydrochloride, 2,2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 4,4-azobis(4-cyanopentanoic acid), 2,2-azobisisobutyronitrile (2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2-isopropylbutyronitrile), 2,2-azobis(2,3-dimethylbutyronitrile), 2,2-azobis(2,4-dimethylbutyronitrile), 2,2-azobis(2,2-azobis(2,4-dimethylbutyronitrile), 2,2-azobis(2,3-dimethylbutyronitrile), 2,2-azobis(2,4 ...3-dimethylbutyronitrile), 2,2-azobis(2,3-dimethylbutyronitrile), 2,2-azobis(2,3-dimethylbutyron Bis(2-methylhexanonitrile), 2,2-azobis(2,3,3-trimethylbutyronitrile), 2,2-azobis(2,4,4-trimethylvaleronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2,4-dimethyl-4-ethoxyvaleronitrile), 2,2-azobis(2,4-dimethyl-4-n-butoxyvaleronitrile), 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2-azobis(N-butyl-2-propenyl) Azo compounds such as 2,2-azobis(N-cyclohexyl-2-methylpropionamide), 1,1-azobis(1-acetoxy-1-phenylethane), 1,1-azobis(cyclohexane-1-nitrile), dimethyl-2,2-azobis(2-methylpropionate), dimethyl 2,2-azodiisobutyrate, dimethyl-2,2'-azobis(2-methylpropionate), 2-(aminoformylazo)isobutyronitrile, and 4,4-azobis(4-cyanopentanoic acid) are used. These polymerization initiators can be used individually or in combination of two or more.

[0256] In addition, the above-mentioned persulfate and organic peroxide polymerization initiators can be combined with reducing agents such as sodium formaldehyde sulfoxylate, sodium bisulfite, ammonium bisulfite, sodium thiosulfate, ammonium thiosulfate, hydrogen peroxide, sodium hydroxymethanesulfinate, L-ascorbic acid and its salts, cuprous salts, and ferrous salts to be used as redox polymerization initiators.

[0257] In emulsified polymerization, the polymerization initiator is preferably a water-soluble polymerization initiator that can be emulsified in water.

[0258] Examples of water-soluble initiators mentioned above include: ammonium persulfate (ammonium perdisulfate), potassium persulfate, sodium persulfate, and other persulfates.

[0259] 2,2-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2-Azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2-Azobis(2-amidinylpropane) dihydrochloride, 2,2-Azobis[N-(2-carboxyethyl)-2-methylpropamidin] hydrate, 2,2-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} disalt Azo compounds such as salts, 2,2-azobis[2-(2-imidazolin-2-yl)propane], 2,2-azobis(1-imino-1-pyrrolyl-2-ethylpropane) dihydrochloride, 2,2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], and 4,4-azobis(4-cyanopentanoic acid):

[0260] These water-soluble polymerization initiators can be used individually or in combination of two or more.

[0261] The polymer particles described above are preferably polymerized first based on (meth)acrylic acid reactive functional groups, thereby containing unreacted non-(meth)acrylic acid reactive functional groups in the polymer particles. If polymerization is first carried out based on non-(meth)acrylic acid reactive functional groups, it may result in poor absorption of non-reactive solvents.

[0262] <Chain transfer agent>

[0263] Chain transfer agents can be used in the polymerization of reactive monomers. Examples of chain transfer agents include: n-hexanethiol, n-octylthiol, tert-octylthiol, n-dodecylthiol, tert-dodecylthiol, and other alkyl thiols.

[0264] Phenolic compounds such as α-methylstyrene dimer, 2,6-di-tert-butyl-4-methylphenol, and styrylated phenol;

[0265] Allyl compounds such as allyl alcohol;

[0266] Halogenated hydrocarbons such as dichloromethane, dibromomethane, and carbon tetrachloride;

[0267] These chain transfer agents can be used individually or in combination of two or more. The maximum amount of chain transfer agent used is 10 parts by mass relative to 100 parts by mass of the reactive monomer.

[0268] <surfactants>

[0269] Surfactants can be used in the polymerization of reactive monomers. There are no particular limitations on the types of surfactants used; for example, widely known surfactants can be used.

[0270] Surfactants can be categorized as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. These surfactants can be used individually or in combination of two or more. Among these surfactants, anionic surfactants are preferred.

[0271] The upper limit for the use of surfactants is typically 5 parts by mass, relative to 100 parts by mass of reactive monomers.

[0272] Anionic surfactants are widely available in commercially available products. For example, one such commercially available product is "Akuaron AR-1025" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.

[0273] <Dispersing agents>

[0274] When producing polymer particles, hydrophilic monomers can be used as reactive monomers other than those for (meth)acrylic acid. This is because hydrophilic monomers can act as dispersing agents, further enhancing dispersion stability during polymerization.

[0275] There are no particular limitations on the types of hydrophilic monomers mentioned above; for example, widely known hydrophilic monomers can be used. Examples of hydrophilic monomers include: carboxyl-containing vinyl monomers and their salts; sulfone-containing vinyl monomers and vinyl sulfate monoesters and their salts; phosphate-containing vinyl monomers and their salts; hydroxyl-containing vinyl monomers; nitrogen-containing vinyl monomers, etc. These hydrophilic monomers can be used individually or in combination of two or more.

[0276] Examples of vinyl monomers containing carboxyl groups include: maleic acid (anhydride), monoalkyl maleate esters, fumaric acid, monoalkyl fumarate esters, crotonic acid, itaconic acid, monoalkyl itaconic acid esters, ethylene glycol monoether of itaconic acid, citraconic acid, monoalkyl citraconic acid esters, cinnamic acid, and their salts. Examples of their salts include alkali metal salts (sodium salts, potassium salts, etc.), ammonium salts, amine salts, and quaternary ammonium salts of the aforementioned vinyl monomers containing carboxyl groups. The aforementioned vinyl monomers containing carboxyl groups and their salts can be used individually or in combination of two or more.

[0277] Vinyl monomers and vinyl sulfate monoesters containing sulfonic acid groups include, for example: vinyl sulfonic acid, (meth)allyl sulfonic acid, p-styrene sulfonic acid, sulfopropyl (meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl sulfonic acid, 2-(meth)acrylamidoamino-2,2-dimethylethanesulfonic acid, 2-(meth)acryloyloxyethanesulfonic acid, 3-(meth)acryloyloxy-2-hydroxypropanesulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, 3-(meth)acrylamido-2-hydroxypropanesulfonic acid, alkyl (C3 to 18) aryl sulfosuccinic acid, poly(n=2 to 30) oxyalkylene (ethylene, propylene, butene, etc.: can be mono, random or block) mono(meth)acrylate sulfate [poly(n=5 to 15) oxypropylene monomethacrylate sulfate, etc.] and their salts. Examples of their salts include: alkali metal salts (sodium salts, potassium salts, etc.), ammonium salts, amine salts, and quaternary ammonium salts of the aforementioned vinyl monomers containing sulfonic acid groups and vinyl sulfate monoesters. The aforementioned vinyl monomers containing sulfonic acid groups and vinyl sulfate monoesters and their salts can be used individually or in combination of two or more.

[0278] Among the aforementioned vinyl monomers containing sulfonic acid groups and vinyl sulfate monoesters and their salts, sodium p-styrene sulfonate is preferred from the viewpoint of further improving dispersion stability during polymerization.

[0279] Vinyl monomers containing phosphate groups include, for example, 2-hydroxyethyl (meth)acryloyl phosphate, phenyl-2-acryloyloxyethyl phosphate, and their salts. These salts include, for example, alkali metal salts (sodium salts, potassium salts, etc.), ammonium salts, amine salts, and quaternary ammonium salts of the aforementioned phosphate-containing vinyl monomers. The aforementioned phosphate-containing vinyl monomers and their salts can be used individually or in combination of two or more.

[0280] Examples of vinyl monomers containing hydroxyl groups include: hydroxystyrene, N-hydroxymethyl (meth)acrylamide, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, and (meth)allyl alcohol. These hydroxyl-containing vinyl monomers can be used individually or in combination of two or more.

[0281] Nitrogen-containing vinyl monomers include, for example, aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, (meth)acrylamide, N-methyl (meth)acrylamide, N-butylacrylamide, diacetone acrylamide, (meth)acrylonitrile, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylamide, etc., which are fourth-order compounds of vinyl monomers containing tertiary amines (substances quaternized using quaternizing agents such as chloromethane, dimethyl sulfate, benzyl chloride, and dimethyl carbonate).

[0282] (b) Absorption of non-reactive solvents

[0283] The absorption of the non-reactive solvent by the aforementioned polymer particles can be performed during or after the production of the polymer particles. Furthermore, the absorption of the non-reactive solvent can be carried out in the presence or absence of an immiscible dispersion medium. When carried out in the presence of a dispersion medium, the absorption of the non-reactive solvent can be performed efficiently, and is therefore preferred. When a solvent is used in the method for manufacturing the polymer particles, that medium can be used directly as the dispersion medium; alternatively, after the polymer particles are separated from the medium, they can be dispersed using other dispersion media.

[0284] For dispersion media containing the aforementioned polymer particles, adding an immiscible, non-reactive solvent and stirring for a certain period of time allows the polymer particles to absorb the non-reactive solvent.

[0285] The absorption of non-reactive solvents during the manufacture of the aforementioned polymer particles can be achieved by selecting appropriate dispersion media and non-reactive solvents. For example, when manufacturing polymer particles via emulsion polymerization in an aqueous solution, a non-reactive solvent immiscible with water can be added beforehand, allowing the production and absorption of polymer particles to occur simultaneously during the polymerization of reactive monomers. By simultaneously carrying out the production and absorption of polymer particles, the time spent on solvent absorption can be reduced.

[0286] <Dispersion Medium>

[0287] The dispersion medium is not particularly limited as long as it is a liquid that does not completely dissolve the polymer particles. Examples include: natural water, purified water, distilled water, ion-exchanged water, pure water, etc.

[0288] Alcohol solvents such as methanol, ethanol, butanol, isobutanol, and n-propanol;

[0289] Ketone solvents such as acetone, methyl ethyl ketone, methyl acetone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and diacetone alcohol;

[0290] Ether solvents such as ethylene glycol mono-n-propyl ether, diethylene glycol mono-n-propyl ether, and propylene glycol monomethyl ether;

[0291] Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, and butyl lactate;

[0292] Hydrocarbon solvents such as toluene, xylene, solvent oil, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane;

[0293] Halogen-based solvents such as chloromethane, dichloromethane, chloroform, and carbon tetrachloride;

[0294] These dispersion media can be used individually or in combination of two or more.

[0295] <Non-reactive solvents>

[0296] There are no particular limitations on non-reactive solvents as long as they are immiscible with the dispersion medium. Here, "immiscible with the dispersion medium" means that the solubility of the non-reactive solvent in the dispersion medium (at 25°C) is 10% by weight.

[0297] For example, when using ion-exchanged water as the dispersion medium, the following non-reactive solvents can be used: butane, pentane, hexane, cyclohexane, heptane, decane, hexadecane, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, 1,4-dioxane, chloromethane, dichloromethane, chloroform, carbon tetrachloride, etc. These non-reactive solvents can be used individually or in combination of two or more.

[0298] Although not specifically limited, the amount of non-reactive solvent added is 20 to 5000 parts by mass relative to 100 parts by mass of polymer particles. When it is less than 20 parts by mass, the hollow portion of the resulting microcapsule particles or hollow particles is too small, and the desired properties cannot be obtained. When it exceeds 5000 parts by mass, the hollow portion is too large and the strength of the resulting microcapsule particles or hollow particles decreases.

[0299] (B) Phase separation step

[0300] After the polymerization step, the remaining reactive functional groups are polymerized, and the polymer and non-reactive solvent phases are separated. Through phase separation, microcapsule particles containing non-reactive solvent can be obtained.

[0301] In this specification, the term "hollow in the hollow particle" does not only refer to the presence of air in the hollow part, but also includes the presence of gases other than air in the hollow part.

[0302] Furthermore, in this specification, hollow particles are not limited to hollow particles in which gas exists in the hollow portion, but also include microcapsule particles in which non-reactive solvents or other dispersion media exist in the hollow portion.

[0303] The added compound for polymerizing the residual reactive functional groups may be the same substance as the polymerization initiator for polymerizing (meth)acrylic acid reactive functional groups and the crosslinking agent (crosslinking monomer) for polymerizing non-(meth)acrylic acid reactive functional groups described in the above polymerization steps.

[0304] (C) Solvent removal (solvent replacement) step

[0305] If necessary, the non-reactive solvent encapsulated in the microcapsule particles can be removed or replaced to obtain hollow particles containing air and other solvents in the hollow part.

[0306] There are no particular limitations on the methods for removing non-reactive solvents; examples include vacuum distillation. The conditions for vacuum distillation are not particularly limited and can be appropriately selected according to the type of non-reactive solvent. The pressure used for vacuum distillation should be, for example, below 500 Pa. The temperature used for vacuum distillation should be, for example, above 30°C and below 200°C. The time used for vacuum distillation should be, for example, above 30 minutes and below 50 hours.

[0307] Alternatively, solvent replacement can be performed by replacing the non-reactive solvent. This operation involves, for example, adding a suitable dispersion medium to microcapsule particles or dispersions containing a non-reactive solvent, stirring to replace the non-reactive solvent inside the particles with the dispersion medium, and then removing excess non-reactive solvent and dispersion medium by vacuum distillation, centrifugation, ultrafiltration, or similar methods. The solvent replacement operation can be performed once or multiple times. Vacuum distillation is preferred to promote the esterification reaction. Heating is more preferably performed during vacuum distillation.

[0308] (D) Dispersion steps

[0309] Hollow particle dispersions, such as microcapsules containing non-reactive solvents obtained after a phase separation step, can maintain the state of a dispersion or be a dispersion after solvent displacement. In the case of solvent displacement, the existing solvent is removed after the phase separation step, and the hollow particles are then dispersed in the desired dispersion medium.

[0310] Examples of the aforementioned dispersion media include: natural water, purified water, distilled water, ion-exchange water, pure water, etc.

[0311] Alcohol solvents such as methanol, ethanol, butanol, isobutanol, and n-propanol;

[0312] Ketone solvents such as acetone, methyl ethyl ketone, methyl acetone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and diacetone alcohol;

[0313] Ether solvents such as ethylene glycol mono-n-propyl ether, diethylene glycol mono-n-propyl ether, and propylene glycol monomethyl ether;

[0314] Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, and butyl lactate;

[0315] Hydrocarbon solvents such as toluene, xylene, solvent oil, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane;

[0316] Halogen-based solvents such as chloromethane, dichloromethane, chloroform, and carbon tetrachloride;

[0317] Such dispersion media can be used individually or in combination of two or more. Example

[0318] The present invention will now be specifically described based on embodiments, but the invention is not limited to these embodiments. In the following embodiments and comparative examples, "room temperature" means a temperature in the range of 20°C to 25°C.

[0319] First, the measurement and evaluation methods in the examples will be explained. Hereinafter, the hollow particle propylene glycol monomethyl ether acetate dispersions obtained in Examples 1 to 3 will also be referred to as "hollow particle dispersions obtained in the examples," and the hollow particle alcohol dispersions obtained in the comparative examples will be referred to as "hollow particle dispersions obtained in the comparative examples." Furthermore, the hollow particle propylene glycol monomethyl ether acetate dispersions obtained in Examples 1 to 3 and the hollow particle alcohol dispersions obtained in the comparative examples will be collectively referred to as "hollow particle dispersions obtained in the examples and comparative examples."

[0320] <Average particle size of hollow particles contained in the hollow particle aqueous dispersion>

[0321] The average particle size of the hollow particles contained in the hollow particle dispersion was determined by the following method.

[0322] Specifically, the hollow particle aqueous dispersion A (solid concentration = 10% by mass) prepared in Example 1 was diluted with ion-exchanged water to a solid concentration of 0.3% by mass to prepare the hollow particle aqueous dispersion.

[0323] The Z-mean particle size of the prepared hollow particle aqueous dispersion (solids concentration = 0.3 wt%) was determined using a particle size analyzer (VASCOγ, Cordouan Technologies) under the following conditions. This Z-mean particle size includes the average particle size of the hollow particles in the hollow particle aqueous dispersion (solids concentration = 0.3 wt%).

[0324] • Measurement temperature: 25°C

[0325] • Optical path length: 100 μm

[0326] • Measurement time: 60 seconds

[0327] • Cumulative count: 3 times

[0328] • Analytical method: Cumulant

[0329] <Average particle size of the hollow particles contained in the propylene glycol monomethyl ether acetate dispersion>

[0330] The average particle size of the hollow particles contained in the propylene glycol monomethyl ether acetate dispersion was determined by the following method.

[0331] Specifically, the hollow particle dispersions obtained in the examples and comparative examples were further diluted with propylene glycol monomethyl ether acetate to a solids concentration of 0.3% by mass to prepare hollow particle propylene glycol monomethyl ether acetate dispersions.

[0332] The Z-mean particle size of the prepared hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3 wt%) was determined using a particle size analyzer (VASCOγ, Cordouan Technologies) under the following conditions. This Z-mean particle size includes the average particle size of the hollow particles in the propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3 wt%).

[0333] Particle size determination conditions

[0334] • Measurement temperature: 25°C

[0335] • Optical path length: 100 μm

[0336] • Measurement time: 60 seconds

[0337] • Cumulative count: 3 times

[0338] • Analytical method: Cumulant

[0339] <Adhesive hollowness>

[0340] The volume fraction of air contained in the hollow particles of the adhesive (adhesive hollow fraction) (volume %) was determined by the following method.

[0341] Specifically, in a glass bottle, 0.5 parts by mass of the hollow particle dispersion obtained in the examples or the hollow particle dispersion obtained in the comparative examples, 0.95 parts by mass of the carboxyl-containing acrylic resin ("ARUFON UC-3510" manufactured by Dong-A Synthetic Co., Ltd., with an average molecular weight of 2000) as a binder, and 0.5 parts by mass of methanol, each correctly measured, are uniformly mixed using an ultrasonic cleaner to obtain the hollow particle dispersion.

[0342] Next, the resulting hollow particle dispersion is dried in a vacuum dryer at 90°C for 16 hours to completely remove the organic solvents contained in the system by evaporation, thus obtaining an adhesive containing hollow particles.

[0343] The resulting adhesive containing hollow particles was stored in a constant temperature and humidity environment of 23°C and 55% for 30 minutes. The refractive index of the adhesive and the refractive index of the hollow particles contained within it were then measured using an Abbe refractometer (ATAGO Inc.'s "NAR-1T SOLID"). The refractive index of the adhesive was 1.468, and the refractive index of the shell of the hollow particles contained within it was 1.537.

[0344] The refractive index of air is set to 1.00 and the density of air is set to 0 (g / cm³). 3 The refractive index of the hollow particle shell containing the binder is 1.537, and the density of the hollow particle shell is 1.27 (g / cm³). 3 The adhesive has a refractive index of 1.468 and a density of 1.05 g / cm³. 3 Based on this, the volume fraction q (= binder hollowness) of the air in the hollow particles containing the binder is calculated (volume %) by solving the following [Maxwell-Garnett equation]. Furthermore, the density of the hollow particle shell mentioned above refers to the "shell density" shown in Table 2 below.

[0345] [Maxwell-Garnett equations]

[0346] (Na 2 -Nm 2 ) / (Na 2 +2Nm 2 ) = q(Np 2 -Nm 2 ) / (Np 2 +2Nm 2 )

[0347] <Ratio of phosphate ester compounds after solvent washing>

[0348] After washing the hollow particle dispersions obtained in the Examples and Comparative Examples with solvent three times, the content ratio of phosphate ester compounds on the outer surface of the shells of the hollow particles contained in the hollow particle dispersions obtained in the Examples and Comparative Examples was measured as [(mass of phosphate ester compound / (total mass of phosphate ester compound and hollow particles)) × 100] (mass%).

[0349] Specifically, 5 parts by mass of the hollow particle dispersion obtained in the example or 10 parts by mass of the hollow particle dispersion obtained in the comparative example were measured using the conical tube of a centrifuge. The dispersion was centrifuged using a centrifuge (Eppendorf Himac Technologies "CR22N") at a centrifugal acceleration of 42200G, and the supernatant in the conical tube was removed. Next, to wash the hollow particles with solvent, 10 g of propylene glycol monomethyl ether acetate was added as a solvent to redisperse the hollow particles, followed by another centrifugation to remove the supernatant in the conical tube. After three solvent washes with this propylene glycol monomethyl ether acetate, the particles were dried using a vacuum dryer (Tokyo Rika Kiki Co., Ltd., product name "VOS-310C") at a pressure of -0.1 MPa and 90°C for 3 hours to obtain a dried powder.

[0350] The obtained dried powder was subjected to ATR-FTIR infrared spectroscopy analysis under the following conditions to obtain an infrared absorption spectrum. The ratio of absorbance (A1350) to absorbance (A1385) of the obtained infrared absorption spectrum (absorbance ratio: A1350 / A1385) was calculated, and the ratio of phosphate ester compounds after solvent washing was determined using the detection line described below. The determined ratio of phosphate ester compounds was set as the content ratio of phosphate ester compounds on the outer surface of the shell of the hollow particles contained in the hollow particle dispersions obtained in the Examples and Comparative Examples [(mass of phosphate ester compounds / (total mass of phosphate ester compounds and hollow particles)) × 100] (mass%).

[0351] Absorbance (A1350) and absorbance (A1385) were measured using a measuring device called "Nicolet iS5" sold by Thermo Fisher Scientific, connected to the "iD5" manufactured by Thermo Fisher Scientific as an ATR accessory.

[0352] (ATR-FTIR measurement conditions)

[0353]

[0354] The absorbance (A1350) and absorbance (A1385) of the infrared absorption spectrum obtained under the above measurement conditions were obtained by the following peak processing.

[0355] Absorbance (A1350): A straight line is drawn from the infrared absorption spectrum at 1325 cm⁻¹. -1 Up to 1345 cm -1 The lowest absorbance between and from 1395 cm -1 Up to 1435 cm -1The lowest absorbance between these values ​​was used as the baseline, with an absorbance of 1345 cm⁻¹. -1 Up to 1355cm -1 The maximum absorbance between these values ​​is taken as absorbance (A1350).

[0356] Absorbance (A1385): A straight line is drawn from the infrared absorption spectrum at 1325 cm⁻¹. -1 Up to 1345 cm -1 The lowest absorbance between and from 1395 cm -1 Up to 1435 cm -1 The lowest absorbance between these values ​​was used as the baseline, with an absorbance of 1380 cm⁻¹. -1 Up to 1390cm -1 The maximum absorbance between these values ​​is taken as absorbance (A1385).

[0357] In addition, the test line involves adding, relative to the solid content concentration of hollow particle aqueous dispersion A (solid content concentration = 10% by mass) prepared in manufacturing example 1, 10%, 20%, 30%, 40%, and 50% by mass of polyoxyethylene alkyl ether phosphate ("Phosphanol RS-710" manufactured by Toho Chemical Industry Co., Ltd.) and the same mass of n-propanol as hollow particle aqueous dispersion A, to the container. After thorough stirring, the mixture is dried for 3 hours at a pressure of -0.1 MPa and 90°C using a vacuum dryer (manufactured by Tokyo Rika Kiki Co., Ltd., product name "VOS-310C") to obtain dried powder. The absorbance (A1350) and absorbance (A1385) ratio (absorbance ratio: A1350 / A1385) were calculated using the above method. The detection line was obtained by curve fitting the amount of polyoxyethylene alkyl ether phosphate added and the absorbance ratio (A1350 / A1385).

[0358] <Absorbance ratio η (A1100 / A1720)>

[0359] Five parts by mass of the hollow particle dispersion obtained in the example or 10 parts by mass of the hollow particle dispersion obtained in the comparative example were measured using the conical tube of a centrifuge. The dispersions were centrifuged using a centrifuge (Eppendorf Himac Technologies "CR22N") at a centrifugal acceleration of 42200G, and the supernatant in the conical tube was removed. Next, to wash the hollow particles with solvent, 10 g of propylene glycol monomethyl ether acetate was added as a solvent to redisperse the hollow particles, followed by another centrifugation to remove the supernatant in the conical tube. After three solvent washes of the hollow particles with this propylene glycol monomethyl ether acetate, the particles were dried for 3 hours using a vacuum dryer (Tokyo Rika Kiki Co., Ltd., product name "VOS-310C") at a pressure of -0.1 MPa and 90°C to obtain a dried powder.

[0360] The obtained dried powder was subjected to infrared spectroscopy analysis (ATR-FTIR) under the following conditions to obtain infrared absorption spectra. The ratio of absorbance (A1100) to absorbance (A1720) of the obtained infrared absorption spectra was calculated (absorbance ratio: A1100 / A1720).

[0361] Absorbance (A1100) and absorbance (A1720) were measured using a measuring device called "Nicolet iS5" sold by Thermo Fisher Scientific, connected to the "iD5" manufactured by Thermo Fisher Scientific as an ATR accessory.

[0362] (ATR-FTIR measurement conditions)

[0363]

[0364] The absorbance (A1100) and absorbance (A1720) of the infrared absorption spectrum obtained under the above measurement conditions were obtained by the following peak processing.

[0365] Absorbance (A1100): plotted linearly from the infrared absorption spectrum at 1005 cm⁻¹ -1 Up to 1025 cm -1 The lowest absorbance between and from 1200 cm -1 Up to 1215 cm -1 The lowest absorbance between these values ​​was used as the baseline, with an absorbance of 1090 cm⁻¹. -1 Up to 1130cm -1 The maximum absorbance between these values ​​is taken as absorbance (A1100).

[0366] Absorbance (A1720): Based on the 1550 cm⁻¹ infrared absorption spectrum. -1Up to 1815 cm -1 Using a straight line in the nearby region as the baseline, the absorbance is 1700 cm⁻¹. -1 Up to 1740 cm -1 The maximum absorbance between these values ​​is taken as absorbance (A1720).

[0367] The absorbance (A1100) obtained from infrared absorption spectroscopy is derived from the CO stretching vibration of the ester group or the CO stretching vibration of the ether group in the hollow particles, corresponding to the absorbance of the absorption spectrum.

[0368] The absorbance (A1720) obtained from infrared absorption spectroscopy is derived from the C=O stretching vibration of the carbonyl group in the hollow particles, corresponding to the absorbance of the absorption spectrum.

[0369] (Manufacturing Example 1) Manufacturing of hollow particle aqueous dispersion A (solid concentration = 10% by mass)

[0370] Add and dissolve 3600 parts by weight of ion-exchanged water, 1.6 parts by weight of anionic surfactant (Akuaron AR-1025 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), 8.0 parts by weight of sodium p-styrene sulfonate, and 8.0 parts by weight of ammonium persulfate in a 5L stainless steel beaker.

[0371] Add 172 parts by weight of glycidyl methacrylate, 28 parts by weight of 3-methacryloyloxypropyltriethoxysilane, 4.0 parts by weight of n-octyl mercaptan, and 200 parts by weight of toluene to the stainless steel beaker. Stir the mixture at room temperature for 10 minutes using an ultrasonic homogenizer (BRANSON, model SONIFIER450) to prepare an emulsion.

[0372] The prepared emulsion was placed in a 5L reactor equipped with a stirrer and a thermometer. The reactor was heated to 70°C while purging with nitrogen to create a nitrogen atmosphere. The polymerization reaction was carried out at 70°C for 2 hours with stirring. Next, 100 parts by weight of ethylenediamine were added, and the reactor was heated to 80°C under nitrogen atmosphere. The reaction was carried out at 80°C for 16 hours with stirring to obtain a hollow particle dispersion.

[0373] 4000 parts by mass of the obtained hollow particle dispersion were washed with 20000 parts by mass of ion-exchanged water using a ceramic filter with a fine pore size of 50 nm, and then appropriately concentrated and ion-exchanged water was added to bring the solids concentration to 10% by mass to obtain hollow particle aqueous dispersion A (solids concentration = 10% by mass).

[0374] The hollow particle aqueous dispersion A (solid fraction concentration = 10% by mass) contains hollow particles with an average particle size of 80.1 nm.

[0375] The formulation and properties of manufacturing Example 1 are shown in Table 1.

[0376] [Table 1]

[0377]

[0378] (Example 1)

[0379] In a 10L stainless steel beaker, add 120 parts by weight of polyoxyethylene alkyl ether phosphate ("Phosphanol RS-710" manufactured by Toho Chemical Industry Co., Ltd.) as a phosphate compound, and dissolve it with 1000 parts by weight of n-propanol, 600 parts by weight of propylene glycol methyl ether, and 2000 parts by weight of propylene glycol methyl ether acetate.

[0380] In addition, 2000 parts by weight of the hollow particle aqueous dispersion A (solid concentration = 10% by mass) obtained in Example 1 were added and stirred at room temperature for 15 minutes using an ultrasonic homogenizer to prepare the hollow particle dispersion.

[0381] 2000 parts by mass of the prepared hollow particle dispersion were added to a rotary evaporator with a 4L flask. The water, n-propanol, and propylene glycol monomethyl ether were distilled under reduced pressure at a water bath temperature of 70°C and a vacuum of 200 hPa. During the reduced pressure distillation, the hollow particle dispersion in the 4L flask was reduced to 2000 parts by mass, providing an appropriate residual hollow particle dispersion.

[0382] Next, 2000 parts by mass of propylene glycol monomethyl ether acetate were supplied to a 4L eggplant-shaped flask to form 2000 parts by mass of the hollow particle dispersion in a water bath at 70°C and 35 hPa, and solvent replacement was performed using a rotary evaporator.

[0383] After solvent displacement, the solution was cooled to room temperature to obtain a hollow particle propylene glycol monomethyl ether acetate dispersion. Furthermore, the temperature was maintained at 70°C during the solvent displacement process, and the vacuum level was adjusted appropriately from 200 hPa to 35 hPa.

[0384] The hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3% by mass) contains hollow particles with an average particle size of 87.9 nm. The shell density of the hollow particles in the hollow particle propylene glycol monomethyl ether acetate dispersion is 1.27 g / cm³. -3 The hollowness of the adhesive was 35.6% by volume, and the absorbance ratio η (A1100 / A1720) was 0.872. The ratio of phosphate ester compounds after solvent washing (the ratio of phosphate ester compounds adhering to the outer surface of the shell of the hollow particles in the propylene glycol monomethyl ether acetate dispersion of hollow particles obtained in Example 1) was 25.4% by mass.

[0385] (Example 2)

[0386] 120 parts by weight of polyoxyethylene alkyl ether phosphate (Phosphanol RS-710 manufactured by Toho Chemical Industry Co., Ltd.) as a phosphate ester compound were added to a 10L stainless steel flask and dissolved in 3000 parts by weight of n-propanol and 2000 parts by weight of propylene glycol methyl ether acetate.

[0387] In addition, 2000 parts by mass of the hollow particle aqueous dispersion A (solid concentration = 10% by mass) obtained in Example 1 were added and stirred at room temperature for 15 minutes using an ultrasonic homogenizer to prepare the hollow particle dispersion.

[0388] 2000 parts by mass of the prepared hollow particle dispersion were added to a rotary evaporator with a 4L flask. Ion-exchanged water, ion-exchanged water, and n-propanol were distilled under reduced pressure at a water bath temperature of 70°C and a vacuum degree of 200 hPa. During the reduced pressure distillation, the hollow particle dispersion in the 4L flask was reduced to 2000 parts by mass, providing an appropriate residual hollow particle dispersion.

[0389] Next, 2000 parts by mass of propylene glycol monomethyl ether acetate were supplied to a 4L eggplant-shaped flask to form 2000 parts by mass of the hollow particle dispersion in a water bath at 70°C and 35 hPa, and solvent replacement was performed using a rotary evaporator.

[0390] After solvent displacement, the solution was cooled to room temperature to obtain a hollow particle propylene glycol monomethyl ether acetate dispersion. Furthermore, the temperature was maintained at 70°C during the solvent displacement process, and the vacuum level was adjusted appropriately from 200 hPa to 35 hPa.

[0391] The hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3% by mass) contains hollow particles with an average particle size of 80.8 nm. The shell density of the hollow particles in the hollow particle propylene glycol monomethyl ether acetate dispersion is 1.27 g / cm³. 3 The hollowness of the adhesive was 34.6% by volume, and the absorbance ratio η (A1100 / A1720) was 0.882. The ratio of phosphate ester compounds after solvent washing (the ratio of phosphate ester compounds adhering to the outer surface of the shell of the hollow particles in the hollow particle propylene glycol monomethyl ether acetate dispersion obtained in Example 2) was 25.5% by mass.

[0392] (Example 3)

[0393] The amount of polyoxyethylene alkyl ether phosphate (Phosphanol RS-710, manufactured by Toho Chemical Industry Co., Ltd.) used as the phosphate compound was changed from 120 parts by weight to 80 parts by weight, and a hollow particle propylene glycol monomethyl ether acetate dispersion was obtained by the same method as in Example 2. 3000 parts by weight of n-propanol and 2000 parts by weight of propylene glycol monomethyl ether acetate were added to dissolve the phosphate compound.

[0394] The hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3% by mass) contains hollow particles with an average particle size of 84.0 nm. The shell density of the hollow particles in the hollow particle propylene glycol monomethyl ether acetate dispersion is 1.27 g / cm³. -3 The hollowness of the adhesive was 37.0% by volume, and the absorbance ratio η (A1100 / A1720) was 0.831. The ratio of phosphate ester compounds after solvent washing (the ratio of phosphate ester compounds adhering to the outer surface of the shell of the hollow particles in the hollow particle propylene glycol monomethyl ether acetate dispersion obtained in Example 3) was 21.7% by mass.

[0395] (Comparative Example 1)

[0396] 120 parts by weight of polyoxyethylene alkyl ether phosphate (Phosphanol RS-710 manufactured by Toho Chemical Industry Co., Ltd.) as a phosphate ester compound were added to a 10L stainless steel flask and dissolved in 1000 parts by weight of n-propanol, 600 parts by weight of propylene glycol methyl ether, and 2000 parts by weight of propylene glycol methyl ether acetate.

[0397] In addition, 2000 parts by mass of the hollow particle aqueous dispersion A (solid concentration = 10% by mass) obtained in Example 1 were added, and the mixture was stirred at room temperature for 15 minutes using an ultrasonic homogenizer to obtain a hollow particle alcohol dispersion. Furthermore, "hollow particle alcohol dispersion" refers to a dispersion in which hollow particles are dispersed in a mixed solution of n-propanol, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate.

[0398] The hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3% by mass) contained hollow particles with an average particle size of 656 nm. The shell density of the hollow particles in the obtained hollow particle alcohol dispersion was 1.27 g / cm³. -3 The hollowness of the adhesive was 30.9% by volume, and the absorbance ratio η (A1100 / A1720) was 0.777. The ratio of phosphate ester compounds after solvent washing (the ratio of phosphate ester compounds adhering to the outer surface of the shell of the hollow particles in the hollow particle alcohol dispersion obtained in Comparative Example 1) was 20.1% by mass.

[0399] (Comparative Example 2)

[0400] 120 parts by weight of polyoxyethylene alkyl ether phosphate (Phosphanol RS-710 manufactured by Toho Chemical Industry Co., Ltd.) as a phosphate ester compound were added to a 10L stainless steel flask and dissolved in 1000 parts by weight of n-propanol, 600 parts by weight of propylene glycol methyl ether, and 2000 parts by weight of propylene glycol methyl ether acetate.

[0401] In addition, 2000 parts by mass of the hollow particle aqueous dispersion A (solid concentration = 10% by mass) obtained in Example 1 were added and stirred at room temperature for 15 minutes using an ultrasonic homogenizer.

[0402] The stirred hollow particle dispersion was transferred to a 10L reactor and stirred at 70°C for 5 hours, then cooled to room temperature to obtain a hollow particle alcohol dispersion. Furthermore, "hollow particle alcohol dispersion" refers to a dispersion in which hollow particles are dispersed in a mixed solution of n-propanol, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate.

[0403] The hollow particle propylene glycol monomethyl ether acetate dispersion (solids concentration = 0.3% by mass) contains hollow particles with an average particle size of 352 nm. Regarding the hollow particles in the alcohol-based dispersion, the shell density is 1.27 g / cm³. -3 The hollowness of the adhesive was 30.9% by volume, and the absorbance ratio η (A1100 / A1720) was 0.786. The ratio of phosphate ester compounds after solvent washing (the ratio of phosphate ester compounds adhering to the outer surface of the shell of the hollow particles contained in the hollow particle propylene glycol monomethyl ether acetate dispersion obtained in Comparative Example 2) was 20.2% by mass.

[0404] The formulations and properties in the embodiments and comparative examples are shown in Table 2.

[0405] In Table 2, "when raw materials are loaded" refers to the time point when the mixture is stirred for 15 minutes using an ultrasonic homogenizer. "Ratio of phosphate ester compounds at the time of raw material loading" refers to the ratio (by mass) of the amount of phosphate ester compounds to the total amount of solids in the hollow particle aqueous dispersion A (solid concentration = 10% by mass) at the time of raw material loading.

[0406] Table 2

[0407]

[0408] [Examination of the results in Table 2]

[0409] Comparing the values ​​of "average particle size of hollow particles contained in hollow particle propylene glycol monomethyl ether acetate dispersion (solid concentration = 0.3% by mass)" in Examples 1 to 3 in Table 2 with the values ​​of Comparative Examples 1 to 2, it is shown that the hollow particles obtained in Examples 1 to 3 can suppress the aggregation of hollow particles in the dispersion medium.

[0410] Comparing the values ​​of “adhesive hollowness” in Examples 1 to 3 in Table 2 with the values ​​in Comparative Examples 1 to 2, it is shown that the hollow particles obtained in Examples 1 to 3 can prevent the collapse of the hollow part due to deformation.

[0411] In Examples 1 to 3, it is presumed that esterification reaction was induced on the outer surface of the hollow particle shell by vacuum distillation, resulting in the chemical attachment of phosphate ester compounds to the outer surface of the hollow particle shell. Furthermore, it is presumed that the hollow particles obtained in Examples 1 to 3 have phosphate ester compounds chemically attached to the outer surface of the shell by esterification reaction and phosphate ester compounds attached via electrostatic interaction.

[0412] On the other hand, in Comparative Examples 1 and 2, since no vacuum distillation was performed, no esterification reaction occurred on the outer surface of the hollow particle shell. As a result, it is speculated that the phosphate ester compound adhered to the outer surface of the hollow particle shell via electrostatic interaction.

[0413] In Examples 1 to 3, it is believed that the phosphate ester compound can chemically adhere to the outer surface of the hollow particle shell, thereby inhibiting the temporary detachment of the phosphate ester compound and improving dispersibility [in other words, the average particle size of the hollow particles contained in the propylene glycol monomethyl ether acetate dispersion (solid concentration = 0.3% by mass) is reduced].

Claims

1. A hollow particle having a shell and a hollow portion surrounded by the shell, said hollow particle having an esterified surface.

2. The hollow particle as described in claim 1, wherein, The hollow particles have a surface treated with esterification by a phosphate compound.

3. The hollow particle as described in claim 2, wherein, The phosphate ester compound is a compound represented by the following formula (1), In formula (1), R1 represents a straight-chain or branched alkyl group having 3 to 19 carbon atoms, a straight-chain or branched alkoxy group having 3 to 19 carbon atoms, an allyl group, a (meth)acryloyl group, a (meth)acryloyloxy group, or a styryl group. R2 represents a hydrogen atom or a methyl group; m represents a number greater than 0 and less than 30; n represents 1 or 2.

4. The hollow particle as described in claim 1, wherein, The shell contains (meth)acrylic resin, The (meth)acrylic resin contains polymers derived from (meth)acrylic reactive monomers having epoxy groups and / or polymers derived from (meth)acrylic reactive monomers having oxybutyl groups.

5. The hollow particle as described in claim 1, wherein, The ratio η (absorbance ratio η: A1100 / A1720) of the infrared absorption spectrum obtained by ATR-FTIR determination of the hollow particles is greater than 0.800 and less than 2.

000.

6. The hollow particle as described in claim 1, wherein, The shell contains inorganic components.

7. The hollow particle as described in claim 1, wherein, The average particle size is 10 to 200 nm.

8. The hollow particle as described in claim 1, wherein, Hollowness ratio 31.0% to 70.0% of volume.

9. A dispersion comprising hollow particles according to any one of claims 1 to 8.

10. A coating agent comprising hollow particles according to any one of claims 1 to 8.

11. A heat insulation film comprising hollow particles according to any one of claims 1 to 8.

12. An antireflective film comprising hollow particles according to any one of claims 1 to 8.

13. A light extraction membrane comprising hollow particles according to any one of claims 1 to 8.

14. A low dielectric constant film comprising hollow particles according to any one of claims 1 to 8.

15. A photosensitive resin composition comprising hollow particles according to any one of claims 1 to 8.

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