Resin particles and method for producing the same

Abstract

The present invention relates to resin particles and a method for manufacturing the resin particles. The resin particles have resin mother particles and silica particles. The silica particles are present on the surface of the resin mother particles, contain a quaternary ammonium salt, and have a hydrophobized surface. When the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles before cleaning is set as detection temperature A, and the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles after cleaning is set as detection temperature B, the difference between the detection temperature A and the detection temperature B (detection temperature A - detection temperature B) is greater than 50°C.

Description

Technical Field

[0001] The present invention relates to resin particles and a method for manufacturing the resin particles. Background Art

[0002] Japanese Patent Application Laid-Open No. 2017-39618 proposes "a silica powder containing a plurality of silica particles in which a quaternary ammonium salt is introduced into a silica structure having "Si-O" bonds as repeating units".

[0003] Japanese Patent Application Laid-Open No. 2019-73418 proposes "a hydrophobic silica powder characterized in that (1) the degree of hydrophobicity is 50% or more; (2) the extraction amount X of at least one compound selected from the group consisting of quaternary ammonium ions, monoazo-based complexes, and inorganic acid root ions extracted using a mixed solvent of methanol and an aqueous methanesulfonic acid solution is 0.1% by mass or more; and (3) the above X and the extraction amount Y of the above compound extracted using water satisfy the relationship Y / X < 0.15".

[0004] Japanese Patent Application Laid-Open No. 2009-114338 proposes "a rubber composition characterized by containing fine particles of surface-treated zeolite as a rubber component with a diene-based rubber". Summary of the Invention

[0005] Technical Problem to be Solved by the Invention

[0006] The technical problem to be solved by the present invention is to provide a resin particle and a method for manufacturing the resin particle. When the resin particle contains a resin mother particle and silica particles present on the surface of the resin mother particle, and the silica particles are silica particles containing a quaternary ammonium salt and having a hydrophobic surface treatment, compared with the case where the detection temperature A of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particle before cleaning is set as the detection temperature A, and the detection temperature B of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particle after cleaning is set as the detection temperature B, the difference (detection temperature A - detection temperature B) between the above detection temperature A and the above detection temperature B is 50°C or less; or the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F BEFORE / the following F AFTER ) is less than 0.9 or greater than 1.1; or the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F SINTERING / the following F BEFORE ) is less than 5 or greater than 20, the resin particle of the present invention has a small charge amount and good dispersibility in a hydrophobic material.

[0007] Means for Solving the Technical Problem

[0008] According to the first aspect of the present invention, there is provided a resin particle having a resin mother particle and silica particles. The silica particles are present on the surface of the resin mother particle, contain a quaternary ammonium salt, and have a hydrophobized surface. When the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry of the resin particles before cleaning is defined as detection temperature A, and the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry of the resin particles after cleaning is defined as detection temperature B, the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) is greater than 50°C.

[0009] According to the second aspect of the present invention, there is provided a resin particle having a resin mother particle and silica particles. The silica particles are present on the surface of the resin mother particle, contain a quaternary ammonium salt, and have a hydrophobized surface. The ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F BEFORE / the following F AFTER ) is 0.9 or more and 1.1 or less, and the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F SINTERING / the following F BEFORE ) is 5 or more and 20 or less.

[0010] F BEFORE : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles before cleaning.

[0011] F AFTER : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles after cleaning.

[0012] F SINTERING : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles obtained by firing the silica particles before cleaning at 700°C.

[0013] According to the third aspect of the present invention, the above quaternary ammonium salt contains a compound represented by the following general formula (AM).

[0014]

[0015] (In the general formula (AM), R 1 , R 2 , R 3 and R 4 each independently represent an alkyl group, an aralkyl group or an aryl group which may or may not have a substituent, and X - represents an anion. In the general formula (AM), R 1 , R2 , R 3 and R 4 Two or more of them can be connected to each other to form a ring.)

[0016] According to the fourth aspect of the present invention, the number average particle diameter D50p of the above-mentioned silica particles is 5 nm or more and 200 nm or less.)

[0017] According to the fifth aspect of the present invention, the number average particle diameter D50p of the above-mentioned silica particles is 5 nm or more and 100 nm or less.)

[0018] According to the sixth aspect of the present invention, the proportion N of the amount of nitrogen element detected by oxygen-nitrogen analysis in the above-mentioned silica particles (N / silica particles × 100) is 0.01 or more and 1.0 or less.)

[0019] According to the seventh aspect of the present invention, the average pore diameter of the above-mentioned silica particles is 0.55 nm or more and 2.00 nm or less.)

[0020] According to the eighth aspect of the present invention, the electrostatic capacitance ratio of the above-mentioned resin particles (the following C AFTER / the following C BEFORE ) is 1.5 or less.)

[0021] C BEFORE : The electrostatic capacitance of the resin particles separated from the above-mentioned mixture after mixing the resin particles before cleaning and the glass particles under specific conditions.)

[0022] C AFTER : The electrostatic capacitance of the resin particles separated from the above-mentioned mixture after mixing the resin particles after cleaning and the glass particles under specific conditions.)

[0023] According to the ninth aspect of the present invention, the above-mentioned silica particles are silica particles further containing aluminum atoms.)

[0024] According to the tenth aspect of the present invention, the above-mentioned silica particles containing aluminum atoms are silica particles surface-treated with an aluminum compound.)

[0025] According to the eleventh aspect of the present invention, the ratio (Si / Al) of the amount of silicon element detected by X-ray photoelectron spectroscopy in the above-mentioned silica particles containing aluminum atoms to the amount of aluminum element detected by X-ray photoelectron spectroscopy is 0.01 or more and 0.30 or less.)

[0026] According to the twelfth aspect of the present invention, the volume average particle diameter D50v of the above-mentioned resin master particles is 1 μm or more and 40 μm or less.)

[0027] According to the 13th aspect of the present invention, the above resin masterbatch particles contain at least one of a vinyl-based resin and a polycondensation-based resin.

[0028] According to the 14th aspect of the present invention, the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) is 60°C or more and 120°C or less.

[0029] According to the 15th aspect of the present invention, there is provided a method for manufacturing the above resin particles, which has a step of producing silica particles and a step of attaching the produced silica particles to the surface of the resin masterbatch particles. The step of producing silica particles produces silica particles through the following steps: a preparation step of preparing a suspension containing silica particles; a first surface treatment step of mixing the above suspension with a quaternary ammonium salt and performing surface treatment on the above silica particles with the quaternary ammonium salt; and a second surface treatment step of performing surface treatment on the silica particles surface-treated with the quaternary ammonium salt using a silicone compound by supercritical treatment.

[0030] Advantages of the Invention

[0031] According to the above 1st, 3rd, 9th or 10th aspect, there is provided a resin particle. When the resin particle contains a resin masterbatch particle and silica particles present on the surface of the above resin masterbatch particle, and the above silica particles are silica particles containing a quaternary ammonium salt and having a hydrophobic surface treatment, compared with the following situation, the resin particle provided by the above aspect has less charge amount and good dispersibility in a hydrophobic material. The situation is: when the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particle before cleaning is set as detection temperature A, and the detection temperature of the pyrolysis product of the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particle after cleaning is set as detection temperature B, the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) is 50°C or less.

[0032] According to the above 2nd aspect, there is provided a resin particle. When the resin particle contains a resin masterbatch particle and silica particles present on the surface of the above resin masterbatch particle, and the above silica particles are silica particles containing a quaternary ammonium salt and having a hydrophobic surface treatment, compared with the ratio of the maximum value of the frequency of the pore diameter of the above silica particles being 2 nm or less (the above F BEFORE / the above F AFTER ) being less than 0.9 or greater than 1.1, or the ratio of the maximum value of the frequency of the pore diameter of the above silica particles being 2 nm or less (the above F SINTERING / the above F BEFORE ) being less than 5 or greater than 20, the resin particle provided by the above aspect has less charge amount and good dispersibility in a hydrophobic material.

[0033] According to the above-described fourth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the number average particle diameter D50p of the above-described silica particles is less than 5 nm or greater than 200 nm.

[0034] According to the above-described fifth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the number average particle diameter D50p of the above-described silica particles is less than 5 nm or greater than 100 nm.

[0035] According to the above-described sixth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the proportion (N / silica particle × 100) of the amount N of nitrogen element detected by oxygen-nitrogen analysis of the above-described silica particles is less than 0.01 or greater than 1.0.

[0036] According to the above-described seventh aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the average pore diameter of the above-described silica particles is less than 0.55 nm or greater than 2.00 nm.

[0037] According to the above-described eighth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the ratio of the electrostatic capacitances of the above-described resin particles (the above C AFTER / the above C BEFORE ) is greater than 1.5.

[0038] According to the above-described eleventh aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the ratio (Si / Al) of the amount Si of silicon element detected by X-ray photoelectron spectroscopy to the amount Al of aluminum element detected by X-ray photoelectron spectroscopy in the above-described silica particles containing aluminum atoms is less than 0.01 or greater than 0.30.

[0039] According to the above-described twelfth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the volume average particle diameter D50v of the above-described resin mother particles is less than 1 μm or greater than 40 μm.

[0040] According to the above-described thirteenth aspect, there is provided a resin particle which has a smaller charge amount and good dispersibility in a hydrophobic material as compared with the case where the above-described resin mother particles contain a resin other than a vinyl-based resin and a condensation-based resin.

[0041] According to the above-mentioned 14th solution, a resin particle is provided. Compared with the case where the difference between the above-mentioned detection temperature A and the above-mentioned detection temperature B (detection temperature A - detection temperature B) is less than 60°C or greater than 120°C, the resin particle provided by this solution has a small charge amount and good dispersibility in a hydrophobic material.

[0042] According to the above-mentioned 15th solution, a method for manufacturing a resin particle is provided. This manufacturing method can obtain a resin particle with a small charge amount and good dispersibility in a hydrophobic material. Detailed implementation manners

[0043] The implementation manners of the present invention will be described below. These descriptions and examples are used to illustrate the implementation manners and do not limit the scope of the implementation manners.

[0044] In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of the other numerical ranges described in other stages. In addition, in the numerical ranges described in the present invention, the upper limit value or the lower limit value of this numerical range can be replaced with the values shown in the examples.

[0045] Each component in this specification may contain two or more corresponding substances.

[0046] In this specification, when referring to the amounts of the respective components in the composition, when there are two or more substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the two or more substances present in the composition.

[0047] In this specification, the term "step" not only includes independent steps, but also includes this term even when it cannot be clearly distinguished from other steps as long as the desired purpose of this step can be achieved.

[0048] <Resin particles>

[0049] The resin particles of the first implementation manner contain resin master particles and silica particles present on the surface of the above-mentioned resin master particles.

[0050] Moreover, the above-mentioned silica particles contained in the resin particles of the first implementation manner are silica particles containing a quaternary ammonium salt and having a hydrophobic treatment on the surface.

[0051] In addition, in the resin particles of the first embodiment, when the detection temperature of the quaternary ammonium salt pyrolysis product obtained by pyrolysis mass spectrometry in the resin particles before cleaning is defined as detection temperature A, and the detection temperature of the quaternary ammonium salt pyrolysis product obtained by pyrolysis mass spectrometry in the resin particles after cleaning is defined as detection temperature B, the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) is greater than 50°C.

[0052] The resin particles of the second embodiment contain resin mother particles and silica particles present on the surface of the above resin mother particles.

[0053] Moreover, the above silica particles contained in the resin particles of the second embodiment are silica particles containing a quaternary ammonium salt and having a hydrophobized surface.

[0054] In addition, among the above silica particles contained in the resin particles of the second embodiment, the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F BEFORE / the following F AFTER ) is 0.9 or more and 1.1 or less, and the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less (the following F SINTERING / the following F BEFORE ) is 5 or more and 20 or less.

[0055] F BEFORE : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles before cleaning.

[0056] F AFTER : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles after cleaning.

[0057] F SINTERING : The maximum value of the frequency of the pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles after firing the silica particles before cleaning at 700°C.

[0058] Hereinafter, the resin particles of the first embodiment and the resin particles of the second embodiment are also collectively referred to as the resin particles of the present embodiment.

[0059] Silica particles are added to hydrophobic materials in various applications such as fillers and thixotropy imparting agents. However, existing silica particles tend to have a large charge amount on the particle surface. Therefore, in a mixture containing silica particles and a hydrophobic material, the silica particles are charged, and as a result, the mixture is charged.

[0060] In addition, the silica particles tend to aggregate in the mixture. Therefore, the mixture is liable to be locally and significantly charged at the portions where the silica particles have aggregated. As a result, the mixture is liable to accumulate static electricity at the portions where the silica particles are locally concentrated.

[0061] By having the above-described configuration, the resin particles of the present embodiment become resin particles having a small charge amount and excellent dispersibility in a hydrophobic material.

[0062] Moreover, for example, when the resin particles of the present embodiment are added to a hydrophobic material to form a mixture, the silica particles can be added to the hydrophobic material in a state where aggregation is suppressed.

[0063] The reason is not necessarily clear, but it is presumably as follows.

[0064] The silica particles contained in the resin particles of the present embodiment contain a quaternary ammonium salt. The quaternary ammonium salt has a positive charge, and compared with silica particles not containing a quaternary ammonium salt, the silica particles containing a quaternary ammonium salt tend to be less likely to be triboelectrically charged as a whole because of the presence of charges having a polarity opposite to that of the silica surface on the particle surface. As a result, the charge amount of the silica particles containing a quaternary ammonium salt is small. Along with this, the charge amount of the resin particles having silica particles containing a quaternary ammonium salt also decreases.

[0065] Moreover, in the resin particles of the first embodiment, the difference (detection temperature A - detection temperature B) between the detection temperature A, which is the detection temperature of the pyrolysis product from the quaternary ammonium salt obtained by pyrolysis mass spectrometry measured before and after cleaning, and the detection temperature B is greater than 50°C. Before and after cleaning the resin particles, the arrangement of the quaternary ammonium salt in the silica particles is different, and thus the detection temperature of the quaternary ammonium salt is different before and after cleaning. And the fact that the difference (detection temperature A - detection temperature B) between the detection temperature A and the detection temperature B is greater than 50°C indicates a state where the quaternary ammonium salt is not easily released from the silica particles. This is because, in the resin particles before cleaning, the quaternary ammonium salt contained in the silica particles exists deep in the pores of the silica particles.

[0066] For the above reasons, even when the resin particles of the first embodiment are added to a hydrophobic material or the like, the quaternary ammonium salt is not easily released from the silica particles, and the state where the charge amount of the silica particles is small can be maintained. Along with this, the charge amount of the resin particles having the silica particles also decreases.

[0067] In the resin particles of the second embodiment, the ratio of the maximum value of the frequency of the pore diameter of the silica particles being 2 nm or less before and after cleaning (the above F BEFORE / the above F AFTER) is 0.9 or more and 1.1 or less, and is the ratio of the maximum value of the frequency of the pore diameter of the silica particles before and after firing being 2 nm or less (the above F SINTERING / the above F BEFORE ) is 5 or more and 20 or less.

[0068] First, the ratio of the maximum value of the frequency of the pore diameter of the silica particles before and after firing being 2 nm or less (the above F SINTERING / the above F BEFORE ) being 5 or more and 20 or less indicates that since quaternary ammonium salts are present inside the pores of the silica particles before firing, the pores are mostly filled, but when the quaternary ammonium salts are removed by the firing step, pores are likely to appear on the silica surface. That is, it indicates that the silica particles contained in the resin particles of the second embodiment tend to contain quaternary ammonium salts inside the pores.

[0069] Moreover, the ratio of the maximum value of the frequency of the pore diameter of the silica particles before and after cleaning being 2 nm or less (the above F BEFORE / the above F AFTER ) being 0.9 or more and 1.1 or less indicates that the amount of quaternary ammonium salts entering the pores of the silica particles does not easily change before and after cleaning. That is, it indicates that even when cleaning is performed, the quaternary ammonium salts contained inside the pores of the silica particles do not easily dissociate.

[0070] For the above reasons, in the resin particles of the second embodiment, the quaternary ammonium salts entering the pores of the silica particles are in a state where they do not easily dissociate from the silica particles. Thus, even when the resin particles of the second embodiment are added to a hydrophobic material or the like, the quaternary ammonium salts do not easily dissociate from the silica particles, and the state of the silica particles having a small charge amount can be maintained. Along with this, the charge amount of the resin particles having such silica particles also decreases.

[0071] In addition, the surface of the silica particles contained in the resin particles of the present embodiment has been hydrophobized and has a tendency to have good affinity with hydrophobic materials. And since the resin particles of the present embodiment have silica particles with a hydrophobic surface treatment, they have good affinity with hydrophobic materials. Therefore, when the resin particles of the present embodiment are added to a hydrophobic material or the like, the dispersibility of the resin particles in the hydrophobic material is improved.

[0072] For the above reasons, the resin particles of the present embodiment become resin particles with a small charge amount and good dispersibility in a hydrophobic material by having the above configuration.

[0073] Further, for example, when the resin particles of the present embodiment are added to a hydrophobic material to form a mixture, the resin particles are well dispersed in the hydrophobic material. As a result, the silica particles contained in the resin particles are contained in the hydrophobic material in a state where aggregation is suppressed. In addition, since the resin particles of the present embodiment have a small charge amount, the charging of the mixture is also suppressed.

[0074] Next, an example of the resin particles of the present embodiment will be described in detail. It should be noted that the resin particles of the present embodiment may be resin particles corresponding to any one of the resin particles of the first and second embodiments.

[0075] (Resin master particle)

[0076] The resin master particle is a particle to which silica particles are attached.

[0077] Regarding the resin master particle, there are no particular limitations as long as it has a shape, particle size, and material (composition) to which silica particles can be attached, and it can be determined according to the use of the resin particles of the present embodiment and the relationship with the silica particles.

[0078] The resin master particle contains resin.

[0079] As the resin contained in the resin master particle, thermoplastic resins formed from various natural or synthetic polymer substances can be cited.

[0080] As the resin contained in the resin master particle, for example, the following resins are used alone or in combination: polyolefin resins such as polyethylene and polypropylene; polystyrene resins such as polystyrene and acrylonitrile / butadiene / styrene copolymer (ABS resin); acrylic resins such as polymethyl methacrylate and polybutyl acrylate; rubber-like (co)polymers such as polybutadiene and polyisoprene; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; vinyl resins such as vinyl chloride resin, vinyl aromatic resin, and polyvinyl resin; epoxy resin; conjugated diene resin; polyamide resin; polyacetal resin; polycarbonate resin; polyurethane resin; fluororesin; and so on.

[0081] As the resin contained in the resin master particle, from the aspect of not easily affecting the charge amount of the silica particles and obtaining resin particles with good dispersibility in the hydrophobic material, at least one of vinyl resins and polycondensation resins is preferred.

[0082] The vinyl resin refers to a resin obtained by polymerizing monomers having vinyl groups.

[0083] As vinyl-based resins, specifically, homopolymers of the following monomers or copolymers formed by combining two or more of these monomers, etc. can be cited: monomers having a styrene skeleton (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.); monomers having a (meth)acrylate skeleton (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.); monomers having an ethylenically unsaturated nitrile skeleton (e.g., acrylonitrile, methacrylonitrile, etc.); monomers having a vinyl ether skeleton (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.); monomers having a vinyl ketone skeleton (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.); monomers having an olefin skeleton (e.g., ethylene, propylene, butadiene, etc.); and so on.

[0084] Condensation resins refer to resins obtained through condensation reactions.

[0085] As condensation resins, polyester resins, polyamide resins, polyacetal resins, polycarbonate resins, polyurethane resins, etc. can be cited.

[0086] As condensation resins, polyester resins are more preferably used.

[0087] As polyester resins, specifically, condensates of polycarboxylic acids and polyols can be cited.

[0088] As polycarboxylic acids, for example, aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, pentenedioic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their acid anhydrides, or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters can be cited. Among these, as polycarboxylic acids, for example, it is preferred to use at least aliphatic dicarboxylic acids, their acid anhydrides or their lower alkyl esters, and more preferably to use aliphatic dicarboxylic acids, their acid anhydrides or their lower alkyl esters and aromatic dicarboxylic acids, their acid anhydrides or their lower alkyl esters.

[0089] As polycarboxylic acids, diacids can also be used in combination with polycarboxylic acids having a crosslinked structure or a branched structure with 3 or more carbon atoms. As polycarboxylic acids having 3 or more carbon atoms, for example, trimellitic acid, pyromellitic acid, their acid anhydrides or their lower (e.g., having 1 to 5 carbon atoms) alkyl esters, etc. can be cited.

[0090] Polycarboxylic acids can be used alone or in combination of two or more.

[0091] As the polyol, for example, aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.) can be cited. Among these, as the polyol, aliphatic diols and alicyclic diols are preferably used, and aliphatic diols are more preferably used.

[0092] As the polyol, a diol can also be used in combination with a polyol having a crosslinked structure or a branched structure and having 3 or more hydroxyl groups. As the polyol having 3 or more hydroxyl groups, for example, glycerin, trimethylolpropane, and pentaerythritol can be cited.

[0093] The polyol can be used alone or in combination of two or more.

[0094] From the aspect of not easily affecting the charge amount of the silica particles and being able to obtain resin particles having good dispersibility in a hydrophobic material, the volume average particle diameter D50v of the resin mother particles is preferably 1 μm or more and 40 μm or less, more preferably 3 μm or more and 20 μm or less, and still more preferably 4 μm or more and 10 μm or less.

[0095] The volume average particle diameter D50v of the resin mother particles is measured using a Coulter Multisizer II (manufactured by Beckman Coulter) and using ISOTON-II (manufactured by Beckman Coulter) as the electrolyte.

[0096] At the time of measurement, 0.5 mg or more and 50 mg or less of the measurement sample is added to 2 ml of a 5 mass% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. The sample is added to 100 ml or more and 150 ml or less of the electrolyte.

[0097] The electrolyte in which the sample is suspended is subjected to a dispersion treatment for 1 minute using an ultrasonic disperser, and the individual particle diameters in the range of 2 μm or more and 60 μm or less are measured using a pore having a pore diameter of 100 μm with a Coulter Multisizer II. The number of sampled particles is 50,000.

[0098] For the measured particle diameters, a cumulative distribution based on volume is plotted from the small diameter side, and the particle diameter at the cumulative 50% point is defined as the volume average particle diameter D50v.

[0099] The weight average molecular weight of the resin mother particles is preferably 5,000 or more and 100,000 or less, more preferably 10,000 or more and 60,000 or less, and still more preferably 20,000 or more and 30,000 or less.

[0100] The mass average molecular weight is defined as the value measured by the GPC (gel permeation chromatography) method. In the molecular weight measurement using GPC, GPC·HLC-8120GPC manufactured by Tosoh Corporation is used as the measurement device, column·TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation is used, and the measurement is carried out using a tetrahydrofuran (THF) solvent. The weight average molecular weight and the number average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

[0101] It should be noted that the resin masterbatch particles may contain additives such as ultraviolet absorbers and antioxidants depending on the intended use.

[0102] (Silica particles)

[0103] The details of the silica particles present on the surface of the resin masterbatch particles will be described below.

[0104] Here, as a method for making silica particles present on the surface of the resin masterbatch particles, a method of mixing silica particles with resin masterbatch particles described later can be cited.

[0105] - Composition of silica particles -

[0106] The silica particles are silica particles containing a quaternary ammonium salt and having a hydrophobic surface treatment.

[0107] Here, as a method for hydrophobic surface treatment of silica particles, it is described in the method for manufacturing silica particles described later.

[0108] · Quaternary ammonium salt

[0109] The silica particles contain a quaternary ammonium salt.

[0110] The quaternary ammonium salt can be used alone or in combination of two or more.

[0111] The quaternary ammonium salt is not particularly limited, and known quaternary ammonium salts can be applied.

[0112] From the aspect of further reducing the charge amount of resin particles, the quaternary ammonium salt preferably contains a compound represented by the general formula (AM). The compound represented by the general formula (AM) can be used alone or in combination of two or more.

[0113]

[0114] In the general formula (AM), R 1 , R 2 , R 3 and R 4 each independently represent an alkyl group, an aralkyl group or an aryl group which may or may not have a substituent, and X -Represents an anion.

[0115] As R 1 ~R 4 Examples of the alkyl group represented by R

[0116] include linear alkyl groups having 1 to 20 carbon atoms and branched alkyl groups having 3 to 20 carbon atoms.

[0117] Examples of the linear alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, etc.

[0118] Among the above groups, as the alkyl group represented by R 1 ~R 4 preferably include alkyl groups having 1 to 15 carbon atoms such as methyl, ethyl, butyl, and tetradecyl.

[0119] As R 1 ~R 4 Examples of the aralkyl group represented by R

[0120] include aralkyl groups having 7 to 30 carbon atoms.

[0121] Among the above groups, as the aralkyl group represented by R 1 ~R 4 preferably include aralkyl groups having 7 to 15 carbon atoms such as benzyl, phenethyl, phenylpropyl, and 4-phenylbutyl.

[0122] As R 1 ~R 4 Examples of the aryl group represented by R

[0123] include aryl groups having 6 to 20 carbon atoms such as phenyl, pyridyl, naphthyl, and anthryl.

[0124] Among the above groups, as the aryl group represented by R 1 ~R4 The aryl group represented is preferably an aryl group having 6 to 10 carbon atoms such as a phenyl group.

[0125] As X - Examples of the anion represented include organic anions and inorganic anions.

[0126] Examples of the organic anion include a polyfluoroalkylsulfonate ion, a polyfluoroalkylcarboxylate ion, a tetraphenylborate ion, an aromatic carboxylate ion, an aromatic sulfonate ion (such as a 1-naphthol-4-sulfonate ion), and the like.

[0127] Examples of the inorganic anion include MoO 4 2- , OH - , F - , Fe(CN) 6 3- , Cl - , Br - , NO 2 - , NO 3 - , CO 3 2- , PO 4 3- , SO 4 2- and the like.

[0128] In the general formula (AM), two or more of R 1 , R 2 , R 3 and R 4 can be linked to each other to form a ring. As R 1 , R 2 , R 3 and R 4 The rings formed by linking two or more of them include an alicyclic ring having 2 to 20 carbon atoms, a heterocyclic amine having 2 to 20 carbon atoms, and the like.

[0129] In the silica particles of the present embodiment, from the aspect of further reducing the charge amount of the resin particles, in the compound represented by the general formula (AM), R 1 , R 2 , R 3 and R 4 preferably each independently represent an alkyl group having 1 to 16 carbon atoms with or without a substituent or an aralkyl group having 7 to 10 carbon atoms.

[0130] The following shows X in the compound represented by the general formula (AM) -Examples of structures other than this are shown, but the present embodiment is not limited thereto.

[0131]

[0132] · Aluminum atom

[0133] The silica particles are preferably silica particles containing aluminum atoms.

[0134] In the silica particles containing aluminum atoms, the aluminum atoms tend to interact with the quaternary ammonium salts, and thus tend to more easily fix the quaternary ammonium salts to the silica particles. Therefore, the quaternary ammonium salts are less likely to be released from the silica particles, and the state of the silica particles with a small charge amount can be further maintained. Thus, the resin particles having silica particles containing aluminum atoms can further maintain the state of having a small charge amount.

[0135] From the aspect of maintaining the state of the resin particles with a small charge amount, aluminum atoms can be included in the silica particles by surface treatment with an aluminum compound.

[0136] Examples of the aluminum compound include compounds in which aluminum atoms are bonded to organic groups via oxygen atoms.

[0137] As the organic group (including the above oxygen atom) bonded to the aluminum atom in the aluminum compound, at least one group selected from the group consisting of an alkoxy group, an acyloxy group, an alkylacetoacetate group (anion of an alkylacetoacetate compound), and an acetylacetonate group (anion of an acetylacetone compound) is preferably used, and at least one group selected from the group consisting of an alkoxy group and an alkylacetoacetate group (anion of an alkylacetoacetate compound) is more preferably used.

[0138] Specific examples of the aluminum compound in which an organic group is bonded to an aluminum atom via an oxygen atom include aluminum alkoxides such as aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum isobutoxide, aluminum sec-butoxide, and aluminum tert-butoxide; chelates such as diisopropoxyaluminum (ethyl acetoacetate), aluminum tris(ethyl acetoacetate), bis(ethyl acetoacetate)·monoacetylacetone aluminum, and aluminum acetylacetonate; aluminum oxide organic acid salts such as aluminum oxide 2-ethylhexanoate and aluminum oxide laurate; complexes of β-diketones such as acetylacetonate and aluminum; complexes of β-keto esters such as ethyl acetoacetate and aluminum; complexes of carboxylic acids such as acetic acid, butyric acid, lactic acid, and citric acid with aluminum; and the like.

[0139] From the aspects of the controllability of the reaction rate, the shape, particle size, and particle size distribution of the obtained silica particles, the above aluminum compound is preferably an aluminum compound having one or more (more preferably two or more) alkoxy groups. That is, the aluminum compound is preferably an aluminum compound in which one or more (more preferably two or more) alkoxy groups (alkyl groups bonded to an aluminum atom through one oxygen atom) are bonded to the aluminum atom. From the aspects of the controllability of the reaction rate, the shape, particle size, and particle size distribution of the obtained silica composite particles, the number of carbon atoms of the alkoxy group is preferably 8 or less, more preferably 2 or more and 4 or less.

[0140] Among them, from the aspect of hardness uniformity, the above aluminum compound is particularly preferably at least one compound selected from the group consisting of (ethyl acetoacetate) diisopropoxyaluminum, tris(ethyl acetoacetato)aluminum, bis(ethyl acetoacetate)·mono(acetylacetonato)aluminum, and tris(acetylacetonato)aluminum.

[0141] Here, as a method for surface-treating silica particles with an aluminum compound, it is described in the method for manufacturing silica particles described later.

[0142] ·Ratio of the amount of nitrogen element N present (N / silica particles × 100)

[0143] From the aspect of further reducing the charge amount of resin particles, the ratio of the amount of nitrogen element N present (N / silica particles × 100) detected by oxygen / nitrogen analysis from the quaternary ammonium salt in the silica particles is preferably 0.01% or more, more preferably 0.02% or more and 1.00% or less, and further preferably 0.03% or more and 0.80% or less.

[0144] There is no particular limitation on the specific method for making the above ratio (N / silica particles × 100) within the above range. For example, methods such as adjusting the mixing ratio and time of the suspension containing silica particles and the quaternary ammonium salt in the manufacture of silica particles can be cited.

[0145] In oxygen / nitrogen analysis, a measurement with an oxygen / nitrogen analyzer (for example, EMGA-920 manufactured by Horiba, Ltd.) is performed for a cumulative time of 45 seconds to obtain the ratio of the amount of nitrogen element N present (N / whole particles × 100). In the case where a material containing nitrogen such as ammonia is used as a catalyst in the particle manufacturing step, a gas chromatograph mass spectrometer (for example, GCMS-TQ8040NX manufactured by Shimadzu Corporation) is used, and based on the calibration curve of known materials, the ratio of the amount of nitrogen element N present (N / whole particles × 100) of the nitrogen element-containing material used in the manufacturing step is obtained, and the difference is obtained as the amount of nitrogen element present from the quaternary ammonium salt.

[0146] ·Ratio of the amount of silicon element Si present (Si / Al)

[0147] From the aspect of further reducing the charge amount of resin particles, in the silica particles containing aluminum atoms, the ratio (Si / Al) of the abundance Si of silicon element detected by X-ray photoelectron spectroscopy to the abundance Al of aluminum element detected by X-ray photoelectron spectroscopy is preferably 0.01 or more and 0.30 or less, more preferably 0.03 or more and 0.2 or less, and still more preferably 0.05 or more and 0.1 or less.

[0148] There is no particular limitation on the specific method for making the above ratio (Si / Al) within the above range. For example, methods such as adjusting the mixing ratio and time of the suspension containing untreated silica particles and an aluminum compound during the manufacture of silica particles can be cited.

[0149] -Properties of silica particles-

[0150] ·The maximum value of the frequency obtained from the pore size distribution curve by the nitrogen adsorption method

[0151] In silica particles, from the aspect of further reducing the charge amount of resin particles, the ratio of the maximum value of the frequency of the pore diameter of silica particles being 2 nm or less (the following F BEFORE / the following F AFTER ) is preferably 0.9 or more and 1.1 or less, more preferably 0.95 or more and 1.1 or less, and still more preferably 0.97 or more and 1.15 or less.

[0152] In addition, in silica particles, from the aspect of further reducing the charge amount of resin particles, the ratio of the maximum value of the frequency of the pore diameter of silica particles being 2 nm or less (the following F SINTERING / the following F BEFORE ) is preferably 5 or more and 20 or less, more preferably 5 or more and 15 or less, and still more preferably 7 or more and 12 or less.

[0153] F BEFORE : The maximum value of the frequency of the pore diameter being 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles before cleaning.

[0154] F AFTER : The maximum value of the frequency of the pore diameter being 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles after cleaning.

[0155] F SINTERING : The maximum value of the frequency of the pore diameter being 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles obtained by firing the silica particles before cleaning at 700 °C.

[0156] Making the above ratio before and after cleaning (F BEFORE / FAFTER ) There is no particular limitation on the specific method within the above range. For example, a method of using a supercritical fluid in the manufacture of silica particles and surface-treating the silica particles with a quaternary ammonium salt can be cited, etc.

[0157] Making the above ratio (F SINTERING / F BEFORE ) There is no particular limitation on the specific method within the above range. For example, a method of using a supercritical fluid in the manufacture of silica particles and surface-treating the silica particles with a quaternary ammonium salt can be cited, etc.

[0158] Regarding the pore size distribution curve of the nitrogen adsorption method, it is derived from various calculation formulas based on the adsorption isotherm obtained by measuring the nitrogen adsorption amount. First, cool the silica particles as the adsorption material to the liquid nitrogen temperature (-196 °C), introduce nitrogen, and use the constant volume method or the gravimetric method to find its adsorption amount. Slowly increase the pressure of the introduced nitrogen, plot the nitrogen adsorption amount against each equilibrium pressure, and thus produce an adsorption isotherm. Based on this adsorption isotherm, use calculation formulas such as the MP method, HK method, SF method, CY method, etc. to find the pore size distribution curve with the frequency represented on the vertical axis and the pore diameter represented on the horizontal axis. From the obtained pore size distribution curve, find the maximum value of the frequency when the pore diameter is 2 nm or less.

[0159] · The cleaning method of the silica particles in the measurement of the maximum value of the frequency obtained from the pore size distribution curve of the nitrogen adsorption method

[0160] Clean the silica particles as follows.

[0161] Add 1 g of silica particles, 2.5 g of ethanol, and 2.5 g of ion-exchanged water to a 20 ml screw-cap sample bottle, mix them using an ultrasonic cleaner (for example, the bench-top ultrasonic cleaner W-113 manufactured by Honda Electronics Co., Ltd., frequency 45 Hz) to obtain a mixture. Then, centrifuge the above mixture in a centrifuge (for example, FB-4000 manufactured by KURABO Industries Ltd.) at 10,000 rpm for 30 minutes. After discarding the supernatant, take out the sedimented silica particles, repeat this operation 2 times, and dry the silica particles. Use this as the cleaned silica particles.

[0162] · The firing method of the silica particles in the measurement of the maximum value of the frequency obtained from the pore size distribution curve of the nitrogen adsorption method

[0163] Fire the silica particles as follows.

[0164] Add 1 g of silica particles to a 20-ml crucible for firing, and fire the silica particles under a nitrogen atmosphere at 600 °C for 1 hour using a firing machine (e.g., KM-100 manufactured by ADVANTEC Toyo K.K.). The obtained fired product is used as the fired silica particles.

[0165] · Number-average particle diameter D50p of silica particles

[0166] From the aspect of further reducing the charge amount of resin particles, the number-average particle diameter D50p of silica particles is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less, and still more preferably 10 nm or more and 80 nm or less.

[0167] The number-average particle diameter D50p of silica particles is determined as follows.

[0168] Photograph the silica particles using a scanning electron microscope (SEM), and determine the equivalent circle diameter (nm) of each of 100 randomly selected primary particles through image analysis. The equivalent circle diameter at the cumulative number 50% point (e.g., the 50th when the number of measurements is 100) from the small-diameter side in the distribution of the equivalent circle diameters is defined as the number-average particle diameter D50p.

[0169] · Average pore diameter of silica particles

[0170] From the aspect of further reducing the charge amount of resin particles, the average pore diameter of silica particles is preferably 0.55 nm or more and 2.00 nm or less, more preferably 0.55 nm or more and 1.50 nm or less, and still more preferably 0.55 nm or more and 1.00 nm or less.

[0171] Regarding the average pore diameter of silica particles, it is derived from various calculation formulas based on the adsorption isotherm obtained by measuring the nitrogen adsorption amount. First, cool the silica particles as the adsorption material to the liquid nitrogen temperature (-196 °C), introduce nitrogen, and determine its adsorption amount using the constant volume method or the gravimetric method. Slowly increase the pressure of the introduced nitrogen, plot the nitrogen adsorption amount against each equilibrium pressure, and thus prepare the adsorption isotherm. Based on this adsorption isotherm, calculate the average pore diameter using calculation formulas such as the MP method, HK method, SF method, and CY method.

[0172] The nitrogen adsorption measurement is carried out using a high-precision gas adsorption amount measurement device (e.g., BELSORP MAX II of Microtrac BEL) and ultra-high purity nitrogen under liquid nitrogen (77.4 K).

[0173] The specific method for making the average pore diameter of the silica particles within the above range is not particularly limited. For example, the following methods can be cited: 1) a method of adjusting the liquid composition during granulation; 2) a method of adjusting the dropping rate during particle granulation; 3) a method of adjusting the drying temperature; and so on.

[0174] - Method for manufacturing silica particles -

[0175] The method for manufacturing silica particles sequentially includes the following steps: a preparation step of preparing a suspension containing silica particles; a first surface treatment step of mixing the above suspension with a quaternary ammonium salt and performing surface treatment on the above silica particles using the quaternary ammonium salt; and a second surface treatment step of performing surface treatment on the silica particles after being surface-treated with the quaternary ammonium salt using a silicone compound by supercritical treatment.

[0176] The method for manufacturing silica particles has a first surface treatment step. In the first surface treatment step, a quaternary ammonium salt is fixed on the surface of the silica particles. Therefore, charges with opposite polarity to the silica surface exist on the particle surface using the quaternary ammonium salt, making it difficult to generate triboelectric charging and facilitating the production of silica particles with a small charge amount.

[0177] In addition, the method for manufacturing silica particles has a second surface treatment step. In the second surface treatment step, the surface of the silica particles that have been surface-treated with the quaternary ammonium salt is hydrophobized. Therefore, the silica particles have good affinity with hydrophobic materials. Also, when the resin particles of the present embodiment having the silica particles on the surface are added to a hydrophobic material or the like, the dispersibility of the resin particles in the hydrophobic material is improved.

[0178] The steps of the method for manufacturing silica particles will be described in detail below.

[0179] · Preparation step

[0180] The method for manufacturing silica particles includes a preparation step.

[0181] In the preparation step, a suspension containing silica particles is prepared.

[0182] As the preparation step, for example, it includes the step (1-a) of preparing a silica particle suspension containing silica particles.

[0183] In addition, as the preparation step, if necessary, step (1-b) can be included after the above step (1-a). In step (1-b), the above silica particle suspension is mixed with an aluminum compound, and the above silica particles are subjected to aluminum compound treatment.

[0184] As step (1-a), the following steps etc. can be cited for example:

[0185] (i) A step of mixing a solvent containing an alcohol with silica particles to prepare a silica particle suspension; (ii) A step of granulating the silica particles by the sol-gel method to obtain a silica particle suspension.

[0186] As the silica particles used in the above (i), sol-gel silica particles (silica particles obtained by the sol-gel method), aqueous colloidal silica particles, alcoholic silica particles, fumed silica particles obtained by the vapor phase method, fused silica particles, etc. can be cited.

[0187] The solvent containing an alcohol used in the above (i) can be a solvent of a single alcohol or a mixed solvent of an alcohol and other solvents. As the alcohol, lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol can be cited for example. As other solvents, water; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and cellosolve acetate; ethers such as dioxane and tetrahydrofuran; etc. can be cited. In the case of a mixed solvent, the proportion of the alcohol is preferably 80% by mass or more, more preferably 90% by mass or more.

[0188] Step (1-a) is preferably a step of granulating the silica particles by the sol-gel method to obtain a silica particle suspension.

[0189] More specifically, step (1-a) is preferably a sol-gel method including the following steps for example:

[0190] An alkaline catalyst solution preparation step of preparing an alkaline catalyst solution containing an alkaline catalyst in a solvent containing an alcohol, and

[0191] A silica particle generation step of supplying tetraalkoxysilane and an alkaline catalyst to the alkaline catalyst solution to generate silica particles.

[0192] The alkaline catalyst solution preparation step is preferably the following step: preparing a solvent containing an alcohol, and mixing the solvent with an alkaline catalyst to obtain an alkaline catalyst solution.

[0193] The solvent containing an alcohol can be a solvent of a single alcohol or a mixed solvent of an alcohol and other solvents. As the alcohol, lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol can be cited for example. As other solvents, water; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and cellosolve acetate; ethers such as dioxane and tetrahydrofuran; etc. can be cited. In the case of a mixed solvent, the proportion of the alcohol is preferably 80% by mass or more, more preferably 90% by mass or more.

[0194] An alkaline catalyst is a catalyst used to promote the reaction of tetraalkoxysilane (hydrolysis reaction and condensation reaction). Examples of the alkaline catalyst include ammonia, urea, monoamine, etc., and ammonia is particularly preferred.

[0195] From the aspect of improving the particle size uniformity and roundness of the generated silica particles, the concentration of the alkaline catalyst in the alkaline catalyst solution is preferably 0.5 mol / L or more and 1.0 mol / L or less, more preferably 0.6 mol / L or more and 0.8 mol / L or less, and further preferably 0.65 mol / L or more and 0.75 mol / L or less.

[0196] The silica particle generation step is the following step: tetraalkoxysilane and an alkaline catalyst are respectively supplied to the alkaline catalyst solution, and tetraalkoxysilane is reacted (hydrolysis reaction and condensation reaction) in the alkaline catalyst solution to generate silica particles.

[0197] In the silica particle generation step, after the core particles are generated by the reaction of tetraalkoxysilane at the initial stage of the supply of tetraalkoxysilane (core particle generation stage), the silica particles are generated through the growth of the core particles (core particle growth stage).

[0198] Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc. From the aspect of controlling the reaction rate or the shape uniformity of the generated silica particles, tetramethoxysilane or tetraethoxysilane is preferred.

[0199] Examples of the alkaline catalyst supplied to the alkaline catalyst solution include alkaline catalysts such as ammonia, urea, monoamine, quaternary ammonium salt, etc., and ammonia is particularly preferred. The alkaline catalyst supplied together with the tetraalkoxysilane may be of the same type as the alkaline catalyst pre-contained in the alkaline catalyst solution or may be of a different type, and preferably of the same type.

[0200] The supply mode of respectively supplying tetraalkoxysilane and an alkaline catalyst to the alkaline catalyst solution may be a continuous supply mode or an intermittent supply mode.

[0201] In the silica particle generation step, the temperature of the alkaline catalyst solution (temperature at the time of supply) is preferably 5°C or more and 50°C or less, and more preferably 15°C or more and 40°C or less.

[0202] In the silica particle generation step, the temperature of the alkaline catalyst solution (temperature at the time of supply) is preferably 5°C or more and 50°C or less, and more preferably 15°C or more and 40°C or less.

[0203] Step (1-b) is a step of mixing the silica particle suspension with an aluminum compound and subjecting the silica particles to aluminum compound treatment.

[0204] By undergoing step (1-b), the functional groups of the aluminum compound (such as organic groups like alkoxy groups) react with the silanol groups on the surface of the silica particles to form silica particles surface-treated with the aluminum compound.

[0205] Step (1-b) is carried out, for example, by adding an aluminum compound to the silica particle suspension and reacting it under stirring in a temperature range of, for example, 20°C or higher and 80°C or lower.

[0206] As the aluminum compound, a compound having an organic group bonded to an aluminum atom through an oxygen atom is preferred. As such a compound, for example, aluminum alkoxides such as aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum isobutoxide, aluminum sec-butoxide, aluminum tert-butoxide; chelates such as diisopropoxyaluminum (ethyl acetoacetate), aluminum tris(ethyl acetoacetate), bis(ethyl acetoacetate)·monoacetylacetone aluminum, aluminum acetylacetonate; aluminum oxide organic acid salts such as aluminum oxide 2-ethylhexanoate, aluminum oxide laurate; complexes of β-diketones such as acetylacetonate with aluminum; complexes of β-keto esters such as ethyl acetoacetate with aluminum; complexes of amines such as triethanolamine with aluminum; complexes of carboxylic acids such as acetic acid, butyric acid, lactic acid, citric acid with aluminum; and so on.

[0207] From the viewpoints of controlling the reaction rate or the shape, particle size, particle size distribution, etc. of the resulting aluminum-bonded silica particles, the aluminum compound is preferably an aluminum compound having one or more (preferably two or more) alkoxy groups. That is, the aluminum compound is preferably an aluminum compound having one or more (preferably two or more) alkoxy groups (alkyl groups bonded to an aluminum atom through one oxygen atom) bonded to the aluminum atom. From the viewpoints of controlling the reaction rate or the shape, particle size, particle size distribution, etc. of the resulting aluminum-bonded silica particles, the number of carbon atoms of the alkoxy group is preferably 8 or less, more preferably 2 or more and 4 or less.

[0208] Preferred specific examples of the aluminum compound include chelates such as diisopropoxyaluminum (ethyl acetoacetate), aluminum tris(ethyl acetoacetate), bis(ethyl acetoacetate)·monoacetylacetone aluminum, aluminum acetylacetonate.

[0209] Step (1-b) is preferably carried out by mixing the silica particle suspension with an alcohol solution containing an aluminum compound in an alcohol. Therefore, the method for manufacturing silica particles preferably further includes a step of preparing an alcohol solution containing an aluminum compound in an alcohol and carrying out this step in advance.

[0210] As the alcohol, for example, lower alcohols such as methanol, ethanol, n-propanol, isopropanol, and butanol can be cited.

[0211] When the aluminum compound is a compound having an alkoxy group, from the viewpoints of controlling the reaction rate or the shape, particle size, particle size distribution, etc. of the formed aluminum-bonded silica particles, the alcohol is preferably an alcohol having a carbon number less than the carbon number of the alkoxy group of the aluminum compound (specifically, for example, the difference in carbon number is 2 or more and 4 or less).

[0212] The alcohol may be the same type as the alcohol contained in the silica particle suspension or may be a different type, and more preferably the same type.

[0213] In the alcohol solution containing the aluminum compound, the concentration of the aluminum compound is preferably 0.05% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 5% by mass or less.

[0214] Regarding the total amount of the aluminum compound, from the viewpoints of controlling the reaction rate or the shape, particle size, particle size distribution, etc. of the formed aluminum-bonded silica particles, with respect to the solid content of the silica particle suspension, the lower limit is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more, and the upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

[0215] The surface treatment conditions for treating the silica particles with the aluminum compound are not particularly limited. For example, it is carried out by reacting the aluminum compound in the temperature range of 5°C or more and 50°C or less under stirring.

[0216] [First surface treatment step]

[0217] The method for manufacturing silica particles includes a first surface treatment step.

[0218] In the first surface treatment step, the above suspension is mixed with a quaternary ammonium salt to obtain a powder in which the above silica particles are surface-treated with the quaternary ammonium salt.

[0219] In the first surface treatment step, when using the step using a supercritical fluid, the quaternary ammonium salt easily penetrates into the pores of the silica particles, and silica particles can be obtained in which the quaternary ammonium salt contained in the silica particles is not easily detached even after washing.

[0220] In addition, silica particles in which the quaternary ammonium salt contained in the silica particles is not easily detached even after washing can also be obtained by the spray drying method.

[0221] As a preferred example of the quaternary ammonium salt, the same quaternary ammonium salts as those exemplified in the quaternary ammonium salts contained in the silica particles described above can be cited.

[0222] The total amount of the quaternary ammonium salt is preferably 0.5% by mass or more, more preferably 1.5% by mass or more and 10% by mass or less, and still more preferably 2% by mass or more and 5% by mass or less with respect to the solid content of the suspension containing silica particles.

[0223] The surface treatment conditions for treating the silica particles with the quaternary ammonium salt are not particularly limited. For example, it can be carried out by reacting the quaternary ammonium salt in the temperature range of 20°C or more and 50°C or less under stirring.

[0224] The first surface treatment step is carried out, for example, by mixing the silica particle suspension with an alcohol solution containing a quaternary ammonium salt in an alcohol. In addition, it is preferably carried out by passing a supercritical fluid. Therefore, the method for manufacturing silica particles preferably further includes a step of preparing an alcohol solution containing a quaternary ammonium salt in an alcohol, and this step is carried out in advance.

[0225] The alcohol in the alcohol solution containing the quaternary ammonium salt and the alcohol contained in the silica particle suspension may be of the same type or different types, and more preferably of the same type.

[0226] In the alcohol solution containing the quaternary ammonium salt in an alcohol, the concentration of the quaternary ammonium salt is preferably 0.05% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 6% by mass or less.

[0227] Examples of the substance used as the supercritical fluid include carbon dioxide, water, methanol, ethanol, acetone, etc. In the first surface treatment step, from the aspects of treatment efficiency and suppression of the generation of coarse particles, the step of using supercritical carbon dioxide is preferred.

[0228] Specifically, the first surface treatment step is carried out, for example, by the following operation.

[0229] The suspension containing the above-mentioned silica particles and the quaternary ammonium salt are charged into a closed reactor and mixed. Then, liquefied carbon dioxide is introduced into the closed reactor, and the closed reactor is heated and the pressure inside the closed reactor is increased using a high-pressure pump to make the carbon dioxide inside the closed reactor in a supercritical state. After that, liquefied carbon dioxide is allowed to flow into the closed reactor, and supercritical carbon dioxide is allowed to flow out of the closed reactor, thereby making supercritical carbon dioxide flow through the suspension inside the closed reactor. During the period when supercritical carbon dioxide flows through the suspension, the solvent is dissolved in the supercritical carbon dioxide and is removed by being entrained in the supercritical carbon dioxide flowing out of the closed reactor.

[0230] The temperature and pressure in the above-mentioned closed reactor are the temperature and pressure at which carbon dioxide becomes in a supercritical state. The critical point of carbon dioxide is 31.1 °C / 7.38 MPa. At this time, for example, the above-mentioned temperature and pressure are set to a temperature of 40 °C or higher and 200 °C or lower / a pressure of 10 MPa or higher and 30 MPa or lower.

[0231] The flow rate of the supercritical fluid in the first surface treatment step is preferably 80 mL / second or more and 240 mL / second or less.

[0232] [Second surface treatment step]

[0233] The method for manufacturing silica particles further includes a second surface treatment step after the above-mentioned first surface treatment step.

[0234] In the second surface treatment step, the silica particles surface-treated with the above-mentioned quaternary ammonium salt are surface-treated with an organosilicon compound.

[0235] By undergoing the second surface treatment step, the functional groups of the organosilicon compound react with the OH groups on the surface of the silica particles, and for example, there is a tendency to generate silica particles that contain atomic groups forming -Si-O-Si-R (R is an organic group) on the surface.

[0236] The second surface treatment step can use wet treatment or supercritical treatment.

[0237] In the second surface treatment step, from the aspect of obtaining resin particles with good dispersibility in a hydrophobic material, supercritical treatment is preferably used.

[0238] By undergoing the second surface treatment step, silica particles with a hydrophobized surface can be obtained.

[0239] The second surface treatment step using wet treatment is specifically carried out, for example, by the following operations. The silica particle suspension after the first surface treatment step is mixed using a stirrer and simultaneously heated to 60 °C, and an organosilicon compound is added for surface treatment. The duration of stirring is preferably 10 minutes or more and 24 hours or less, more preferably 20 minutes or more and 120 minutes or less, and further preferably 20 minutes or more and 90 minutes or less.

[0240] The second surface treatment step using supercritical treatment is specifically carried out, for example, by the following operations.

[0241] It is known that when using a supercritical fluid, the reaction efficiency between the organosilicon compound and the surface of the silica particles is good, and a high degree of surface treatment can be carried out.

[0242] Examples of substances used as supercritical fluids include carbon dioxide, water, methanol, ethanol, acetone, etc. From the aspects of processing efficiency and suppression of the generation of coarse particles, the second surface treatment step is preferably a step using supercritical carbon dioxide.

[0243] The powder, that is, silica particles surface-treated with a quaternary ammonium salt and an organosilicon compound are placed in a closed reactor equipped with a stirrer. Then, after introducing liquefied carbon dioxide, the closed reactor is heated and pressurized using a high-pressure pump to make the carbon dioxide in the closed reactor reach a supercritical state. After that, the stirrer is operated to stir the reaction system.

[0244] The temperature and pressure in the above-mentioned closed reactor are the temperature and pressure at which carbon dioxide becomes a supercritical state. The critical point of carbon dioxide is 31.1 °C / 7.38 MPa. At this time, for example, the above temperature and pressure are a temperature of 40 °C or higher and 200 °C or lower / a pressure of 10 MPa or higher and 30 MPa or lower. The duration of stirring is preferably 10 minutes or more and 24 hours or less, 20 minutes or more and 120 minutes or less, and more preferably 20 minutes or more and 90 minutes or less.

[0245] Examples of organosilicon compounds also include:

[0246] Silane compounds with lower alkyl groups such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, trimethylmethoxysilane;

[0247] Silane compounds with vinyl groups such as vinyltrimethoxysilane, vinyltriethoxysilane;

[0248] Silane compounds with epoxy groups such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane;

[0249] Silane compounds with styryl groups such as p-styryltrimethoxysilane, p-styryltriethoxysilane;

[0250] Silane compounds with aminoalkyl groups such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutyl)propylamine, N-phenyl-3-aminopropyltrimethoxysilane;

[0251] Silane compounds having isocyanate group alkyl such as 3 - isocyanatopropyltrimethoxysilane, 3 - isocyanatopropyltriethoxysilane;

[0252] Silazane compounds such as hexamethyldisilazane, tetramethyldisilazane; and so on.

[0253] [Solvent removal step]

[0254] The method for manufacturing silica particles may further include a solvent removal step as needed.

[0255] In the solvent removal step, the suspension containing the silica particles surface - treated with the quaternary ammonium salt is dried to remove the solvent, obtaining a powder. As drying, for example, thermal drying, spray drying, and supercritical drying can be cited.

[0256] In thermal drying and spray drying, at the end point of drying, the surface tension easily acts between the particles, so it is easy to generate coarse particles due to particle aggregation. However, by performing surface treatment with organosilicon compounds, the generation of coarse particles can be suppressed.

[0257] Spray drying can be carried out by a known method using a commercially available spray dryer (such as a rotary disk type, nozzle type, etc.). For example, it is carried out by spraying the spray liquid at a speed of 0.2 liters per hour or more and 1 liter per hour or less in a hot air stream. At this time, regarding the temperature of the hot air, it is preferably in the range where the inlet temperature is 70°C or more and 400°C or less, and the outlet temperature is 40°C or more and 120°C or less. Here, if the inlet temperature is less than 70°C, the drying of the solid components contained in the dispersion is insufficient. In addition, if it is higher than 400°C, the shape of the particles is deformed during spray drying. In addition, if the outlet temperature is less than 40°C, the drying degree of the solid components becomes poor and adheres to the inside of the device. A more preferable inlet temperature is in the range of 100°C or more and 300°C or less.

[0258] The concentration of silica particles in the silica particle suspension during spray drying is preferably in the range of 10% by weight or more and 30% by weight or less in terms of solid components.

[0259] In supercritical drying, by removing the solvent using a supercritical fluid, the surface tension between the particles does not easily act, and the primary particles contained in the suspension are dried in a state where aggregation is suppressed. Therefore, it is easy to obtain silica particles with high uniformity in particle size and surface - treated with a quaternary ammonium salt.

[0260] Substances used as supercritical fluids can include carbon dioxide, water, methanol, ethanol, acetone, etc. From the aspects of processing efficiency and suppression of the generation of coarse particles, the solvent removal step is preferably a step using supercritical carbon dioxide.

[0261] The solvent removal step is specifically carried out, for example, by the following operations.

[0262] The suspension is placed in a closed reactor, and then liquefied carbon dioxide is introduced. After that, the closed reactor is heated and pressurized inside the closed reactor using a high-pressure pump to make the carbon dioxide inside the closed reactor in a supercritical state. Then, the liquefied carbon dioxide is allowed to flow into the closed reactor, and the supercritical carbon dioxide flows out of the closed reactor, and the supercritical carbon dioxide is circulated in the suspension inside the closed reactor. During the period when the supercritical carbon dioxide circulates in the suspension, the solvent dissolves in the supercritical carbon dioxide, and the solvent is entrained in the supercritical carbon dioxide flowing out of the closed reactor and is removed.

[0263] The temperature and pressure inside the above-mentioned closed reactor are the temperature and pressure for making carbon dioxide in a supercritical state. The critical point of carbon dioxide is 31.1 °C / 7.38 MPa. At this time, for example, the temperature and pressure are set to a temperature of 40 °C or higher and 200 °C or lower / a pressure of 10 MPa or higher and 30 MPa or lower.

[0264] The flow rate of the supercritical fluid in the solvent removal step is preferably 80 mL / second or more and 240 mL / second or less.

[0265] For the obtained silica particles, it is preferable to perform crushing or screening as needed to remove coarse particles or aggregates. Crushing is carried out, for example, by dry crushing devices such as jet mills, vibration mills, ball mills, and pin-bar crushers. Screening is carried out, for example, by vibrating screens, air classifiers, etc.

[0266] (Properties of resin particles)

[0267] - Pyrolysis mass spectrometry analysis of resin particles -

[0268] In the resin particles of the present embodiment, when the detection temperature of the pyrolysis product from the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles before cleaning is set as detection temperature A, and the detection temperature of the pyrolysis product from the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles after cleaning is set as detection temperature B, the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) is greater than 50 °C.

[0269] By making the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) greater than 50 °C, the quaternary ammonium salt is not easily freed from the silica particles. Therefore, by making the difference between the above detection temperature A and the above detection temperature B (detection temperature A - detection temperature B) greater than 50 °C, the state of the resin particles with a small charge amount can be maintained.

[0270] From the aspect of maintaining a state where the resin particles have a small charge amount, the difference between the above-described detection temperature A and the above-described detection temperature B (detection temperature A - detection temperature B) is preferably greater than 50°C and 250°C or less, more preferably greater than 50°C and 200°C or less, further preferably 60°C or more and 175°C or less, particularly preferably 75°C or more and 150°C or less, and most preferably 75°C or more and 120°C or less.

[0271] From the aspect of maintaining a state where the resin particles have a small charge amount, the above-described detection temperature A is preferably 200°C or more and 700°C or less, more preferably 300°C or more and 500°C or less, further preferably 300°C or more and 400°C or less, and most preferably 300°C or more and 350°C or less.

[0272] In addition, from the aspect of maintaining a state where the resin particles have a small charge amount, the above-described detection temperature B is preferably 150°C or more and 600°C or less, more preferably 200°C or more and 400°C or less, further preferably 200°C or more and 350°C or less, and most preferably 200°C or more and 300°C or less.

[0273] Here, the "pyrolysis product of the quaternary ammonium salt" refers to the component that is volatilized in gaseous form due to the decomposition of the quaternary ammonium salt contained in the silica particles in the resin particles when the resin particles are heated using the pyrolysis device described below. Examples of the pyrolysis product of the quaternary ammonium salt include: a tertiary amine formed by the detachment of one of the four substituents bonded to the nitrogen atom of the quaternary ammonium salt; a secondary amine formed by the detachment of two of the four substituents bonded to the nitrogen atom of the quaternary ammonium salt; a primary amine formed by the detachment of three of the four substituents bonded to the nitrogen atom of the quaternary ammonium salt; and so on.

[0274] The "detection temperature from the pyrolysis product of the quaternary ammonium salt" refers to the temperature corresponding to the peak apex of the peak from the pyrolysis product of the quaternary ammonium salt in the EGA thermogram obtained using the pyrolysis device described below.

[0275] The measurement methods of the above-described detection temperature A and the above-described detection temperature B will be described below.

[0276] The above-described detection temperature A and the above-described detection temperature B are measured using GCMS-QP2020 NX manufactured by Shimadzu Corporation.

[0277] Weigh 10 mg of resin particles and load them into the pyrolysis device. Set the pyrolysis device and gas chromatography-mass spectrometer to the following conditions, conduct pyrolysis mass spectrometry analysis, and obtain the EGA thermogram and MS mass spectrum of the pyrolysis products generated from the resin particles. Then, identify the components contained in the peaks of the obtained EGA thermogram based on the measurement results of the MS mass spectrum. After that, determine the peak from the pyrolysis product of the quaternary ammonium salt among the peaks of the EGA thermogram, and take the temperature corresponding to the peak apex as the detection temperature A.

[0278] In the determination of the detection temperature B, weigh 10 mg of the resin particles that have been subjected to the following cleaning and load them into the pyrolysis device. Except for this, conduct the measurement using the same process as in the measurement process of the detection temperature A.

[0279] Here, the method for determining the peak from the pyrolysis product of the quaternary ammonium salt among the peaks of the EGA thermogram is as follows.

[0280] Conduct gas chromatography-mass spectrometry analysis on the components of each peak from the EGA thermogram, and confirm the MS mass spectrum obtained therefrom. Then, determine the MS mass spectrum in which the fragment ions generated from the pyrolysis product of the quaternary ammonium salt are detected. In the EGA thermogram, the peak corresponding to the MS mass spectrum in which the fragment ions generated from the pyrolysis product of the quaternary ammonium salt are detected is determined as the peak from the pyrolysis product of the quaternary ammonium salt.

[0281] It should be noted that the above determinations of the detection temperature A and the detection temperature B can be carried out with individual silica particles. In the case of conducting the measurement with individual silica particles, except for making the amount of silica particles loaded into the pyrolysis device be 0.5 mg, conduct the above determinations of the detection temperature A and the detection temperature B using the same process as above.

[0282] It should be noted that in the following cleaning, except for adding 0.5 mg of silica particles instead of resin particles, the same process is used.

[0283] When the silica particles pre-contain the same compound as the pyrolysis product of the quaternary ammonium salt, when conducting the above determinations of the detection temperature A and the detection temperature B with individual silica particles, conduct pre-cleaning of the silica particles using the following steps, and then conduct the above pyrolysis mass spectrometry analysis.

[0284] · Pre-cleaning

[0285] Add 1 g of silica particles and 5.0 g of methanol as the cleaning liquid to a 20-ml screw-cap sample bottle, and mix them using an ultrasonic cleaner (for example, the tabletop ultrasonic cleaner W-113 manufactured by Honda Denki Co., Ltd., with a frequency of 45 Hz) to obtain a mixture. Subsequently, centrifuge the above mixture in a centrifuge (for example, FB-4000 manufactured by KURABO Industries Ltd.) at 10,000 rpm for 30 minutes. After discarding the supernatant, take out the sedimented silica particles, and repeat this operation twice to dry the silica particles.

[0286] It should be noted that when the silica particles pre-contain a compound (such as trialkylamine) identical to the pyrolysis product of the quaternary ammonium salt, the identification of the compound identical to the pyrolysis product of the quaternary ammonium salt is carried out by analyzing the cleaning liquid after ultrasonic cleaning in the above pre-cleaning using HPLC (high performance liquid chromatography).

[0287] -Ratio of capacitance-

[0288] In the resin particles, from the aspect of further reducing the charge amount of the resin particles, the ratio of capacitance (hereinafter C AFTER / hereinafter C BEFORE ) is preferably 1.5 or less, more preferably 1.3 or less, and further preferably 1.1 or less.

[0289] C BEFORE : The capacitance of the resin particles separated from the mixture obtained by mixing the resin particles before cleaning and glass particles under specific conditions.

[0290] C AFTER : The capacitance of the resin particles separated from the mixture obtained by mixing the resin particles after cleaning and glass particles under specific conditions.

[0291] There is no particular limitation on the specific method for making the above ratio (C AFTER / C BEFORE ) within the above range. For example, a method of surface-treating silica particles with a quaternary ammonium salt using a supercritical fluid in the manufacture of silica particles can be cited.

[0292] There is no particular limitation on the glass particles, and the SPL series manufactured by Unitika Ltd. is used.

[0293] The specific conditions refer to the following conditions.

[0294] Mass ratio: resin particles / glass particles = 1 / 10

[0295] Mixing temperature: room temperature (10 °C)

[0296] Mixing device: Henschel mixer (e.g., FM mixer manufactured by Nippon Coke & Engineering Co., Ltd.)

[0297] Mixing time: 5 minutes

[0298] Mixing speed: 49 rpm

[0299] The capacitance is measured as follows.

[0300] 2 g of the sample after stirring with a TURBULA Shaker-Mixer is placed in a metal container with a stainless-steel wire mesh having a mesh size of 20 μm, and measured using a charge measurement device (e.g., TB-200 manufactured by Toshiba Chemical Corporation).

[0301] - Method for cleaning resin particles in the measurement of detection temperature B and capacitance measurement -

[0302] The resin particles are cleaned as follows.

[0303] Add 2 g of resin particles, 10 g of ethanol, and 10 g of ion-exchanged water to a 50-ml screw-cap sample bottle, mix using an ultrasonic cleaner (e.g., bench-top ultrasonic cleaner W-113, frequency 45 Hz manufactured by Honda Electronics Co., Ltd.) to obtain a mixture. Thereafter, the above mixture is centrifuged at 10,000 rpm for 30 minutes in a centrifuge (e.g., FB-4000 manufactured by KURABO Industries Ltd.), the supernatant is discarded, the sedimented resin particles are taken out, and this operation is repeated 2 times, and the resin particles are dried. These are used as the cleaned resin particles.

[0304] - Ratio of particle sizes -

[0305] The ratio of the number-average particle size D50p of silica particles to the volume-average particle size D50v of resin base particles (number-average particle size D50p of silica particles / volume-average particle size D50v of resin base particles) is preferably 0.002 or more and 0.05 or less, more preferably 0.004 or more and 0.02 or less, and still more preferably 0.008 or more and 0.015 or less.

[0306] (Method for manufacturing resin particles)

[0307] The resin particles of the present embodiment are obtained by attaching silica particles to the surface of resin base particles.

[0308] As a method for attaching silica particles to the surface of resin base particles, for example, a method of adding silica particles and resin base particles to a V-type mixer, a Henschel mixer, a Lodige mixer, etc. and stirring them can be cited, or silica particles can be attached to the surface of resin base particles in stages.

[0309] In the resin particles of the present embodiment, as described above, it is preferable that silica particles are attached to the surface of the resin base particles in a range where the calculated coating rate is 5% or more and 80% or less.

[0310] In order to make the attachment amount of the silica particles within the above range, it is sufficient to add silica particles in an amount of 0.1% by mass or more and 10% by mass or less based on the total mass of the resin base particles to a V-type blender, a Henschel mixer, a Lodige mixer, or the like.

[0311] Examples

[0312] Examples will be described below, but the present invention is not limited by any of these examples. It should be noted that in the following description, "parts" and "%" are all based on mass unless otherwise specified.

[0313] <Manufacture of silica particles>

[0314] [Silica particles S1 to S9]

[0315] (Preparation step)

[0316] Prepare a suspension containing silica particles as follows.

[0317] - Preparation of alkaline catalyst solution -

[0318] Add the amounts of methanol, ion-exchanged water, and 10% ammonia water (NH 4 OH) shown in Table 1 to a glass reaction vessel equipped with a metal stirring rod, a dropping head, and a thermometer, and stir and mix to obtain an alkaline catalyst solution.

[0319] - Granulation of silica particles by sol-gel method -

[0320] Adjust the temperature of the alkaline catalyst solution to 25°C, and displace the alkaline catalyst solution with nitrogen. Then, while stirring the alkaline catalyst solution, simultaneously add dropwise the amounts of tetramethoxysilane (TMOS) and 176 parts by mass of ammonia water (NH 3 ) with a catalyst (NH 4 OH) concentration of 4.4% to obtain a silica particle suspension.

[0321] - Preparation of alcohol solution containing quaternary ammonium salt -

[0322] Prepare an alcohol solution in which the quaternary ammonium salt of the type shown in Table 1 is diluted with butanol.

[0323] (First surface treatment step)

[0324] Adjust the temperature of the suspension of the above-mentioned silica particles to 25 °C, and add the above-mentioned alcohol solution adjusted to 25 °C. At this time, add the alcohol solution in such a way that the amount of the quaternary ammonium salt is the amount shown in Table 1 relative to 100 parts by mass of the solid component of the silica particle suspension. Then, stir at 30 °C for 30 minutes to obtain a suspension containing silica particles containing a quaternary ammonium salt.

[0325] Next, charge 300 parts by mass of the above-mentioned suspension containing silica particles containing a quaternary ammonium salt into a reaction tank, and add CO under stirring 2 , and raise the temperature and pressure in the reaction tank to 120 °C / 20 MPa. While stirring to maintain the temperature and pressure, flow in and out CO at a flow rate of 5 L / min 2 . Then, remove the solvent over 120 minutes to obtain a powder.

[0326] (Second surface treatment step)

[0327] Relative to 100 parts by mass of the powder remaining in the reaction tank, add 100 parts by mass of 1,1,1,3,3,3 - hexamethyldisilazane (HMDS). While stirring the material, fill the inside of the reaction tank with CO 2 , and raise the temperature and pressure in the reaction tank to 150 °C / 15 MPa. Continue stirring for 30 minutes while maintaining the temperature and pressure. Then, release the pressure until it reaches atmospheric pressure and cool to room temperature (25 °C). Then stop the stirrer to obtain silica particles as a powder.

[0328] [Silica particles CS1]

[0329] Silica particles are manufactured in the same manner as silica particles S1 except that the second surface treatment step is not performed.

[0330] [Silica particles S10]

[0331] (Preparation step)

[0332] - Preparation of alkaline catalyst solution -

[0333] Add the amounts of methanol, ion-exchanged water, and 10% ammonia water (NH 4 OH) shown in Table 1 to a glass reaction vessel equipped with a metal stir bar, a dropping funnel, and a thermometer, and stir and mix to obtain an alkaline catalyst solution.

[0334] - Granulation of silica particles by sol-gel method -

[0335] Adjust the temperature of the alkaline catalyst solution to 45 °C and displace the alkaline catalyst solution with nitrogen. Then, while stirring the alkaline catalyst solution, simultaneously add dropwise 186 parts by mass of tetraethoxysilane (TEOS) and ammonia water (NH 3 ) with a concentration of 4.4% (NH 4 OH) shown in Table 1 to produce a suspension of silica particles.

[0336] - Preparation of Alcohol Solution Containing Quaternary Ammonium Salt -

[0337] Prepare an alcohol solution by diluting the quaternary ammonium salt of the type shown in Table 1 with butanol.

[0338] - Quaternary Ammonium Salt Treatment and Surface Treatment (First and Second Surface Treatment Steps) -

[0339] Adjust the temperature of the suspension of the above silica particles to 25 °C and add the above alcohol solution adjusted to 25 °C. At this time, add the alcohol solution in such a way that the number of parts of the quaternary ammonium salt is the amount shown in Table 1 relative to 100 parts by mass of the solid content of the silica particle suspension. Then stir at 30 °C for 30 minutes to obtain a suspension containing silica particles with a quaternary ammonium salt.

[0340] Next, adjust the temperature of the suspension to 55 °C and add 100 parts by mass of 1,1,1,3,3,3 - hexamethyldisilazane (HMDS) relative to 100 parts by mass of the powder. While stirring the material, perform surface treatment for 1 hour to obtain a suspension of silica particles.

[0341] (Solvent Removal Step)

[0342] The removal of the solvent from the suspension of the above silica particles is carried out using a small spray dryer B - 290 (manufactured by Buchi Japan Co., Ltd.). Set the input temperature in the barrel to 200 °C and feed the silica particle suspension at a feed rate of 0.2 L / hour to obtain dried silica particles after solvent removal by spray drying.

[0343] [Silica Particles CS2]

[0344] Let the first surface treatment step be not performing quaternary ammonium salt surface treatment, that is, the following step. Except for this, manufacture silica particles using the same method as silica particles S1.

[0345] Charge 300 parts by mass of the suspension of the above silica particles into a reaction tank, add CO 2 while stirring, and raise the temperature and pressure in the reaction tank to 120 °C / 20 MPa. While maintaining the temperature and pressure, stir and feed CO at a flow rate of 5 L / min 2Inflow and outflow. Then, the solvent was removed over 120 minutes to obtain a powder.

[0346] [Silica particles CS3]

[0347] Silica particles were produced according to the production method described in Example 1 of Japanese Patent Application Laid-Open No. 2017-39618.

[0348]

[0349] [Silica particles SA11 to SA20]

[0350] (Preparation step)

[0351] First, suspensions in each example were prepared as follows. These suspensions contained silica particles containing aluminum atoms.

[0352] Methanol, ion-exchanged water, and 10% ammonia water (NH 4 OH) in the amounts shown in Table 2 were added to a glass reaction vessel equipped with a metal stir bar, a dropping funnel, and a thermometer, and stirred and mixed to obtain a basic catalyst solution.

[0353] The temperature of the basic catalyst solution was adjusted to 25°C, and the basic catalyst solution was purged with nitrogen. Then, while stirring the basic catalyst solution, a tetraethoxysilane (TMOS) in the amount shown in Table 2 and 176 parts by mass of ammonia water (NH 3 ) with a catalyst (NH 4 OH) concentration of 4.4% were simultaneously added dropwise to obtain a silica particle suspension.

[0354] An alcohol solution was prepared by diluting an aluminum compound ((ethyl acetoacetate) diisopropoxyaluminum, manufactured by Wako Pure Chemical Industries, Ltd.) with butanol to a concentration of 50%.

[0355] The temperature of the silica particle suspension was adjusted to 25°C, and the above-mentioned alcohol solution adjusted to 25°C was added. At this time, the alcohol solution was added in such a manner that 1 part by mass of the aluminum compound was added per 100 parts by mass of the solid content of the silica particle suspension. Then, the mixture was stirred for 30 minutes, whereby the aluminum compound reacted with the surface of the silica particles to perform surface treatment, and a suspension containing silica particles containing aluminum atoms was obtained.

[0356] (First surface treatment step)

[0357] An alcohol solution was prepared by diluting a quaternary ammonium salt of the type and concentration shown in Table 2 with methanol.

[0358] Adjust the temperature of the suspension of the above-mentioned silicon dioxide particles containing aluminum atoms to 25 °C, and add the above-mentioned alcohol solution adjusted to 25 °C. At this time, add the alcohol solution in such a manner that the concentration of the quaternary ammonium salt is the amount shown in Table 2 relative to 100 parts by mass of the solid component of the aluminum-bonded silicon dioxide particle suspension. Then, stir at 30 °C for 30 minutes, thereby causing the quaternary ammonium salt to react with the surface of the aluminum-bonded silicon dioxide particles and performing surface treatment to obtain a suspension containing silicon dioxide particles containing a quaternary ammonium salt and aluminum atoms.

[0359] (Second surface treatment step)

[0360] Add 30 parts by mass of 1,1,1,3,3,3-hexamethyldisilazane (HMDS) to the above-mentioned suspension containing silicon dioxide particles containing a quaternary ammonium salt and aluminum atoms. While stirring the material, fill the reaction tank with CO 2 and raise the temperature and pressure in the reaction tank to 150 °C / 15 MPa. While maintaining the temperature and pressure, stir for 30 minutes and flow CO 2 in and out at a flow rate of 5 L / min, and remove the solvent in 120 minutes to obtain silicon dioxide particles containing a quaternary ammonium salt and aluminum atoms as powders for each example.

[0361] [Silicon dioxide particle CSA4]

[0362] Except for not performing the second surface treatment step, silicon dioxide composite particles are manufactured using the same method as that for silicon dioxide particle SA11.

[0363] [Silicon dioxide particle CSA5]

[0364] Except for not performing the first surface treatment step, silicon dioxide composite particles are manufactured using the same method as that for silicon dioxide particle SA11.

[0365] [Silicon dioxide particle CSA6]

[0366] Granulate the silicon dioxide particles prepared by the sol-gel method in the preparation step into the following steps. Furthermore, without the first surface treatment step, and using the same method as that for silicon dioxide particle SA11 otherwise, silicon dioxide composite particles are manufactured.

[0367] Adjust the temperature of the alkaline catalyst solution to 25 °C, and displace the alkaline catalyst solution with nitrogen. Then, while stirring the alkaline catalyst solution, simultaneously dropwise add 176 parts by mass of tetramethoxysilane (TMOS) shown in Table 2, an alcohol solution containing the amount of quaternary ammonium salt shown in Table 2, and ammonia water (NH 3 ) with a concentration of 4.4% (NH 4 OH) to obtain a silicon dioxide particle suspension.

[0368]

[0369] The abbreviations in each table respectively refer to the following compounds.

[0370] ·TMBAC: Benzyltributylammonium chloride

[0371] ·TP-415: N,N-Dimethyl-N-tetradecyl-1-tetradecanaminium, hexa-μ-oxotetra-μ3-oxodi-μ5-oxotetradecaoxooctamolybdate(4-)(4:1)(N,N-dimethyl-N-tetradecyl-1-tetradecanaminium, hexa-μ-oxotetra-μ3-oxodi-μ5-oxotetradecaoxooctamolybdate(4-)(4:1))

[0372] ·P-51: Benzyltrimethylammonium chloride

[0373] ·ALCH: Diisopropylaluminum (ethyl acetoacetate)

[0374] <Manufacture of resin masterbatch particles>

[0375] The above substances were charged into a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen inlet tube in the proportions of 23 mol% of dimethyl terephthalate, 10 mol% of isophthalic acid, 15 mol% of dodecenyl succinic anhydride, 3 mol% of trimellitic anhydride, 5 mol% of bisphenol A ethylene oxide 2-mole adduct, and 45 mol% of bisphenol A propylene oxide 2-mole adduct. After replacing the inside of the reaction vessel with dry nitrogen gas, dibutyltin oxide was added as a catalyst in a proportion of 0.06 mol%. The mixture was stirred and reacted at about 190 °C for about 7 hours under a nitrogen stream. Further, the temperature was raised to about 250 °C, and after stirring and reacting for about 5.0 hours, the pressure inside the reaction vessel was reduced to 10.0 mmHg, and the stirring reaction was carried out under reduced pressure for about 0.5 hours to obtain a polyester resin.

[0376] Next, 100 parts of the polyester resin was melt-kneaded using a Banbury mixer-type kneader. The kneaded product was formed into a plate with a thickness of about 1 cm using a calender roll, coarsely pulverized to a few millimeters using a Fitz Mill-type pulverizer, finely pulverized using an IDS-type pulverizer, and then classified successively using an elbow jet-type classifier to obtain resin masterbatch particles A with a volume average particle diameter D50v of 7 μm.

[0377] <Examples 1 to 20, Comparative Examples 1 to 6>

[0378] 100 parts of the resin masterbatch of the combination described in Table 3 and 2.0 parts of silica particles were mixed using a Henschel mixer (manufactured by Mitsui Miike Seisakusho) under the conditions of 1,300 rpm for 3 minutes to obtain resin particles.

[0379] <Evaluation>

[0380] (Chargeability evaluation)

[0381] After mixing the resin particles before cleaning and glass particles described in the above capacitance ratio under specific conditions to form a mixture, the capacitance of the resin particles obtained in each example was measured using the same process as the measurement process of the capacitance (C BEFORE ) of the resin particles separated from the above mixture.

[0382] Based on the value of the obtained capacitance (C BEFORE ), the chargeability was evaluated according to the following evaluation criteria.

[0383] G1: C BEFORE Is 35 μF or less, strongly suppressing the increase in capacitance.

[0384] G2: C BEFORE Is greater than 35 μF and 48 μF or less, suppressing the increase in capacitance.

[0385] G3: C BEFORE Is greater than 48 μF and 60 μF or less, and the capacitance slightly increases.

[0386] G4: C BEFORE Is greater than 60 μF, and the capacitance increases.

[0387] (Friction resistance evaluation)

[0388] 55 parts of the resin particles obtained in each example and 100 parts of styrene-butadiene rubber were melt-kneaded using a Banbury mixer type kneader. The kneaded product was formed into a plate with a thickness of about 1 cm using calender rolls as a friction resistance evaluation sample. For the obtained friction resistance evaluation sample, a friction and wear test was performed using a Tribo Gear load-variable friction and wear tester HHS-2000 (manufactured by Shinto Kagaku Co., Ltd.), and the frictional force (gf) for one round trip was measured. For the same friction resistance evaluation sample, the frictional forces (gf) at a total of 5 different measurement positions were measured, and the arithmetic mean and standard deviation of the obtained values were calculated. Using the arithmetic mean and standard deviation, the arithmetic mean ratio (gf ave ) and the standard deviation ratio (gf sta ) were calculated through the following calculation formulas.

[0389] Arithmetic mean ratio (gf ave) = Arithmetic mean of Comparative Example 2 ÷ Arithmetic mean of each example × 100

[0390] Standard deviation ratio (gf sta ) = Standard deviation of Comparative Example 2 ÷ Standard deviation of each example × 100

[0391] Based on the obtained arithmetic mean ratio (gf ave ) and standard deviation ratio (gf sta ), the frictional resistance is evaluated according to the following criteria.

[0392] It should be noted that the higher the value of the arithmetic mean ratio (gf ave ) of the frictional resistance (gf), the greater the effect of suppressing the frictional resistance of the resin particles.

[0393] In addition, the higher the value of the standard deviation ratio (gf sta ) of the frictional resistance (gf), the better the resin particles are dispersed in the rubber.

[0394] - Evaluation criteria based on the arithmetic mean ratio (gf ave ) -

[0395] G1: The arithmetic mean ratio (gf ave ) is greater than 106, strongly suppressing the increase in frictional resistance.

[0396] G2: The arithmetic mean ratio (gf ave ) is greater than 100 and 106 or less, suppressing the increase in frictional resistance.

[0397] G3: The arithmetic mean ratio (gf ave ) is greater than 97 and 100 or less, with a slight increase in frictional resistance.

[0398] G4: The arithmetic mean ratio (gf ave ) is 97 or less, with an increase in frictional resistance.

[0399] - Evaluation criteria based on the standard deviation ratio (gf sta ) -

[0400] G1: The standard deviation ratio (gf sta ) is greater than 105, and the dispersibility of the resin particles in the rubber is very good.

[0401] G2: The standard deviation ratio (gf sta ) is greater than 100 and 105 or less, and the dispersibility of the resin particles in the rubber is good.

[0402] G3: The standard deviation ratio (gf sta ) is greater than 95 and 100 or less, and the dispersibility of the resin particles in the rubber is slightly poor.

[0403] G4: The standard deviation ratio (gf sta ) is 95 or less, and the dispersibility of the resin particles in the rubber is poor.

[0404]

[0405]

[0406] From the above results, it can be seen that the resin particles in this embodiment have a small charge amount and good dispersibility in the hydrophobic material.

Claims

1. A resin particle, which has: A resin master particle; and Silica particles, which are present on the surface of the above resin master particle, contain a quaternary ammonium salt, and the surface of the silica particles is hydrophobized, The detection temperature of the pyrolysis product from the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles before cleaning is set as detection temperature A, and the detection temperature of the pyrolysis product from the quaternary ammonium salt obtained by pyrolysis mass spectrometry in the resin particles after cleaning is set as detection temperature B. In this case, the difference between the above detection temperature A and the above detection temperature B, that is, detection temperature A - detection temperature B, is greater than 50 °C.

2. A resin particle, which has: A resin master particle; and Silica particles, which are present on the surface of the above resin master particle, contain a quaternary ammonium salt, and the surface of the silica particles is hydrophobized, The ratio of the maximum value of the frequency of the pore diameter of the above silica particles being 2 nm or less to the following F BEFORE / the following F AFTER is 0.9 or more and 1.1 or less. The ratio of the maximum value of the frequency of the pore diameter of the above silica particles being 2 nm or less to the following F SINTERING / the following F BEFORE is 5 or more and 20 or less. F BEFORE : The maximum value of the frequency of pores with a pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles before cleaning F AFTER : The maximum value of the frequency of pores with a pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the washed silica particles, F SINTERING : The maximum value of the frequency of pores with a pore diameter of 2 nm or less obtained from the pore size distribution curve by the nitrogen adsorption method in the silica particles after firing the silica particles before cleaning at 700 °C.

3. The resin particle according to claim 1 or claim 2, wherein, The above quaternary ammonium salt contains a compound represented by the following general formula (AM), General formula (AM) In general formula (AM), R 1 , R 2 , R 3 and R 4 each independently represent an alkyl group, an aralkyl group or an aryl group which may or may not have a substituent, and X− represents an anion; in general formula (AM), two or more of R 1 , R 2 , R 3 and R 4 may be linked to each other to form a ring.

4. The resin particle according to claim 1 or 2, wherein, The number average particle diameter D50p of the above silica particles is 5 nm or more and 200 nm or less.

5. The resin particle according to claim 4, wherein, The number average particle diameter D50p of the above silica particles is 5 nm or more and 100 nm or less.

6. The resin particle according to claim 1 or 2, wherein, The proportion of the amount of nitrogen element N detected by oxygen and nitrogen analysis in the above silica particles, that is, N / silica particles × 100, is 0.01 or more and 1.0 or less.

7. The resin particle according to claim 1 or 2, wherein, The average pore diameter of the above silica particles is 0.55 nm or more and 2.00 nm or less.

8. The resin particles according to claim 1 or 2, wherein the ratio of the electrostatic capacitance of the resin particles, namely the following C AFTER / the following C BEFORE is 1.5 or less. C BEFORE : The electrostatic capacitance of the resin particles separated from the above mixture after mixing the resin particles before cleaning with glass particles under specific conditions, C AFTER : The electrostatic capacitance of the resin particles separated from the above mixture after mixing the washed resin particles and glass particles under specific conditions to form a mixture.

9. The resin particle according to claim 1 or 2, wherein, The above silica particles are silica particles further containing aluminum atoms.

10. The resin particle according to claim 9, wherein, The above silica particles containing aluminum atoms are silica particles surface-treated with an aluminum compound.

11. The resin particle according to claim 9, wherein, The proportion of the amount of silicon element Si to the amount of aluminum element Al in the above silica particles containing aluminum atoms, that is, Si / Al, is 0.01 or more and 0.30 or less, The amount of silicon element Si and the amount of aluminum element Al are detected by X-ray photoelectron spectroscopy.

12. The resin particle according to claim 1 or 2, wherein, The volume average particle diameter D50v of the above resin master particle is 1 μm or more and 40 μm or less.

13. The resin particle according to claim 1 or 2, wherein, The above resin master particle contains at least one of a vinyl-based resin and a polycondensation-based resin.

14. The resin particle according to claim 1 or 2, wherein, The difference between the above detection temperature A and the above detection temperature B, that is, detection temperature A - detection temperature B, is 60 °C or more and 120 °C or less.

15. The method for manufacturing the resin particles according to any one of claims 1 to 14, comprising the following steps: A step of producing silica particles; and A step of attaching the produced silica particles to the surface of resin base particles, The step of producing silica particles in the step of producing silica particles produces silica particles through the following steps: A preparation step of preparing a suspension containing silica particles; A first surface treatment step of mixing the suspension with a quaternary ammonium salt and performing surface treatment on the silica particles with the quaternary ammonium salt; and A second surface treatment step of performing surface treatment on the silica particles surface-treated with the quaternary ammonium salt using a silicone compound by supercritical treatment.

Images