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WO2025230016A1 - Particules de silice à faible teneur en méthanol et organosol, et procédé de production associé - Google Patents

Particules de silice à faible teneur en méthanol et organosol, et procédé de production associé

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Publication number
WO2025230016A1
WO2025230016A1 PCT/JP2025/016668 JP2025016668W WO2025230016A1 WO 2025230016 A1 WO2025230016 A1 WO 2025230016A1 JP 2025016668 W JP2025016668 W JP 2025016668W WO 2025230016 A1 WO2025230016 A1 WO 2025230016A1
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WIPO (PCT)
Prior art keywords
group
silica particles
atom
sol
organosol
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/016668
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English (en)
Japanese (ja)
Inventor
和也 江原
豪 中田
圭吾 松本
歳幸 遠藤
真実 下吉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nissan Chemical Corp
Original Assignee
Nissan Chemical Corp
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Filing date
Publication date
Application filed by Nissan Chemical Corp filed Critical Nissan Chemical Corp
Publication of WO2025230016A1 publication Critical patent/WO2025230016A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds

Definitions

  • the present invention relates to silica particles containing aluminum atoms, and in particular to silica particles with a low methanol content, as well as an organosol containing such silica particles.
  • Silica sol is used in a variety of fields as an abrasive, functional inorganic filler, and more.
  • silica sol is stable and does not gel in alkaline conditions
  • acidic conditions the zeta potential of silica particles is small, resulting in little electrical repulsion.
  • silica sol is unstable and prone to gelling, it is often required to use silica sol in acidic conditions, such as in acidic abrasives, raw materials for ceramic fibers, and chromium-based surface treatment agents.
  • One known method for improving the stability of silica sol in the acidic range is to modify the surface of silica particles with an aluminum compound.
  • aluminosilicate sites are formed on the surface of silica particles by reaction between aluminate ions derived from the aluminum compound and silanol groups on the surface of the silica particles.
  • the aluminosilicate sites impart a negative charge to the silica particles, i.e., increase the negative zeta potential of the silica particles, thereby improving the dispersion stability of the silica particles in the dispersion medium. This improves the compatibility of silica particles with highly polar organic solvents and charged resins in particular.
  • Patent Document 1 a method for producing an acidic silica sol has been disclosed (see Patent Document 1 ), in which an aqueous alkali aluminate solution is added to a dispersion of solid silica particles so that the Al2O3 / SiO2 molar ratio is greater than 0.0006 and less than 0.004, and the resulting silica sol is heated at 80 to 250°C, followed by cation exchange.
  • a method for producing a silica sol which includes a step of cation-exchanging an aqueous alkali silicate solution containing aluminum atoms, and heating the resulting activated silicic acid at 80 to 300°C to obtain an aqueous solid silica sol, or a step of cation-exchanging an aqueous alkali silicate solution to which aluminum atoms have been added as an aluminate, and heating the resulting activated silicic acid at 80 to 300 °C to obtain an aqueous solid silica sol, followed by a step of solvent-substitution of the resulting silica sol with a nitrogen-containing solvent.
  • This method discloses a silica sol dispersed in a nitrogen-containing solvent, in which aluminum atoms are bonded to the surfaces of silica particles at a ratio of 800 to 20,000 ppm/ SiO2 in terms of Al2O3, forming aluminosilicate sites (see Patent Document 2).
  • hollow silica particles have a silica outer shell and a space inside the shell, and due to these characteristics, they have properties such as a low refractive index, low thermal conductivity (thermal insulation), and electrical insulation.
  • Hollow silica particles consist of a core corresponding to the hollow portion and an outer shell that forms the outside of the core.
  • An aqueous dispersion of hollow silica particles can be obtained by forming a silica layer on the outside of a template particle in an aqueous medium and then removing the template particle.
  • a method has been disclosed in which a core-shell particle having an aluminosilicate shell is produced by reacting a template core made of an organic polymer in a micellar or reverse micellar form with a silane compound and an aluminum precursor at a Si/Al molar ratio of 7 to 15, and then reacting this with a basic or acidic aqueous solution to simultaneously form pores in the shell (outer shell) and remove the core, followed by heating at 160 to 200°C for a hydrothermal reaction to produce a hollow silica sol with a densified shell (see Patent Document 3).
  • formaldehyde is subject to regulation due to its various harmful effects, including carcinogenicity, and its generation and reduction has become an issue in various materials fields.
  • the field of electronic materials which is one of the fields in which the silica sol is used, it is also desired to reduce formaldehyde in the system.
  • Another object of the present invention is to provide silica particles and silica sol with a reduced methanol content, and a method for producing the same.
  • the present invention provides aluminum atom-containing silica particles, the amount of aluminum atoms present in the entire silica particles is 120 to 50,000 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles;
  • the present invention relates to silica particles, characterized in that the methanol content is less than 800 ppm relative to the mass of the silica particles.
  • the methanol content is The temperature is set to 100°C or higher and 350°C or lower in 50°C increments, and the minimum temperature is set to such that the weight loss rate of the aluminum-atom-containing silica particles after 30 minutes of heating is 0.1 mass% or less.
  • the present invention relates to silica particles according to the first aspect.
  • the silica particles are solid silica particles, porous silica particles, or hollow silica particles, and have an average primary particle diameter of 10 to 140 nm as measured by a BET method.
  • the present invention relates to silica particles according to the first aspect.
  • the silica particles are at least partially coated with a silane compound
  • the silane compound is represented by the following formula (1) and formula (2):
  • R1 is a group bonded to a silicon atom, and each R1 is independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or represents an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si—C bond, or represents a combination of these groups;
  • R2 is a group or atom bonded to a silicon atom, and each R2 independently represents an alkoxy group having one or more carbon atoms, an acyloxy group,
  • At least one silane compound selected from the group consisting of compounds represented by The present invention relates to silica particles according to the first aspect.
  • the present invention relates to the silica particles according to the fourth aspect, in which the silane compound is a compound represented by the following formula (4) or formula (5):
  • R 9 and R 10 each independently represent an alkyl group having 1 to 10 carbon atoms, a hydrogen atom, or a combination of these groups
  • R 8 and R 12 each independently represent an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a group represented by formula (6)
  • R 11 independently represents an alkyl group having 1 to 10 carbon atoms or a combination of such groups
  • n represents an integer of 1 to 20
  • m represents an integer of 1 to 3.
  • a 2 , A 3 , and A 4 each independently represent a methylene group or an oxygen atom, and one of A 2 , A 3 , and A 4 represents an oxygen atom; R A represents a hydrogen atom or a methyl group; * indicates a bond directly connected to a silicon atom or a carbon atom.
  • the present invention relates to the silica particles according to the first aspect, in which a methanol content relative to the mass of the silica particles is less than 200 ppm.
  • a methanol content relative to a mass of the silica particles is less than 100 ppm.
  • the present invention relates to the silica particles according to the first aspect, in which a methanol content relative to a mass of the silica particles is less than 20 ppm.
  • an organosol comprising aluminum atom-containing silica particles, the amount of aluminum atoms present in the entire silica particles being 120 to 50,000 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles, and an organic solvent, wherein the organic solvent comprises at least one selected from the group consisting of ketones, ethers, esters, amides, glycols, and alcohols having two or more carbon atoms;
  • the methanol content in the organosol is less than 800 ppm; Regarding organosols.
  • the silica particles are at least partially coated with a silane compound, and the silane compound is represented by the following formula (7) and formula (8):
  • R 13 is a group bonded to a silicon atom, and each R 13 is independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or represents an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si—C bond, or represents a combination of these groups;
  • R 14 is a group or atom bonded to a silicon atom, and independently represents an alkoxy group having 2 or more carbon atoms, an acyl
  • At least one silane compound selected from the group consisting of compounds represented by The present invention relates to an organosol according to a ninth aspect.
  • the present invention relates to the organosol according to the ninth aspect, which further contains a basic compound.
  • the aluminum atom-containing silica particles in the organosol have an average secondary particle size of 15 to 200 nm as measured by a dynamic light scattering method, The silica particle concentration in the organosol is 1 to 70 mass%.
  • the present invention relates to an organosol according to a ninth aspect.
  • a resin composition comprising the organosol according to the ninth aspect and an organic resin component, wherein the organic resin component is
  • the present invention relates to a resin composition comprising at least one monomer selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, allyl compounds, isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfonyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, divinyl-containing compounds, diallyl-containing compounds, styrene, tetracarboxylic acid anhydrides, bismaleimides, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, and at least one silane compound selected from the group consisting of silane compounds
  • a method for producing the organosol according to the ninth aspect comprising:
  • the present invention relates to a method for producing an organosol, comprising the step of : subjecting a water-dispersed silica sol or a methanol-dispersed silica sol containing aluminum-atom-containing silica particles, the amount of aluminum atoms present in the entire silica particles being 120 to 50,000 ppm/ SiO2, calculated as Al2O3, relative to the mass of the silica particles, to heating under reduced pressure and/or ultrafiltration to replace the methanol with a water-soluble organic solvent other than methanol, thereby obtaining an organosol having a methanol content of less than 800 ppm.
  • the fifteenth aspect relates to a method for producing an organosol, further comprising a step of adding at least one silane compound selected from the group consisting of compounds represented by formula (7) and formula (8) to a sol containing the aluminum atom-containing silica particles, and heating and stirring the mixture at 10°C to 95°C for 0.1 to 20 hours.
  • R 13 is a group bonded to a silicon atom, and each R 13 is independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or represents an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si—C bond, or represents a combination of these groups;
  • R 14 is a group or atom bonded to a silicon atom, and independently represents an alkoxy group having 2 or more carbon atoms, an acyloxy group, a hydroxy group, or a halogen atom, or a combination of these groups or atoms; d represents an integer of 1 to 3;
  • the present invention relates to the method for producing an organosol according to the sixteenth aspect, in which the step of adding the silane compound and heating and stirring is carried out a plurality of times.
  • the solvent substitution step by heating under reduced pressure and/or ultrafiltration further comprising a step of adding a basic compound to increase the pH to 0.1 to 7.
  • the present invention relates to a method for producing an organosol according to any one of the fifteenth to seventeenth aspects.
  • the method further includes a step of replacing the water-soluble organic solvent with an organic solvent having a boiling point higher than that of the water-soluble organic solvent, which contains nitrogen atoms and/or oxygen atoms and has a boiling point of 200 to 300°C or lower.
  • the present invention relates to a method for producing an organosol according to a fifteenth aspect.
  • a method for producing silica particles according to the first aspect comprising a step of heating an organosol containing aluminum atom-containing silica particles and an organic solvent at 50° C. to 200° C.
  • the aluminum atom- containing silica particles have an amount of aluminum atoms present in the entire particle of 120 to 50,000 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles,
  • the organic solvent comprises at least one selected from the group consisting of ketones, ethers, esters, amides, glycols, and alcohols having two or more carbon atoms.
  • the present invention relates to a method for producing an organosol according to the 9th aspect, including a step of mixing the silica particles obtained by the production method according to the 19th aspect with an organic solvent to obtain an organosol having a methanol content of less than 800 ppm.
  • the present invention relates to the organosol according to the ninth aspect, in which the organosol is a sol that satisfies the following formula (X): Formula (X): 4 ⁇ (Pr)/(P0) ⁇ 0.5 (however, (P0) represents the average secondary particle size of the silica particles in the organosol as measured by a dynamic light scattering method, (Pr) represents the average secondary particle diameter of silica particles in a redispersed organosol obtained by removing the organic solvent from the organosol and then redispersing the silica particles in the same organic solvent as the organosol from which the organic solvent was removed at a silica particle concentration of 1 to 70 mass %, as determined by a dynamic light scattering method.
  • formula (X): 4 ⁇ (Pr)/(P0) ⁇ 0.5 (however, (P0) represents the average secondary particle size of the silica particles in the organosol as measured by a dynamic light scattering method, (Pr) represents the average secondary particle diameter of silic
  • the present invention makes it possible to provide silica particles or silica sol with a reduced methanol content. This makes it possible to provide materials that can suppress formaldehyde generation in various resin materials containing these silica particles and silica sol.
  • the present inventors were the first to discover that the presence of methanol in a system has an impact on the reduction of formaldehyde, particularly in the technical fields of silica particles and silica sols, and focused on the methanol content in silica particles and silica sols. Furthermore, to control the methanol content in silica particles, they first removed the solvent from organosilica sols to achieve particles with a low methanol content. Furthermore, in silica sols, the use of methanol and compounds that lead to methanol generation was controlled not only in the dispersion medium used in the sol, but also in the compounds used to modify the surface of silica particles in the sol and in other additives, thereby achieving a sol with a low methanol content.
  • silica particles for example, hollow silica particles and porous silica particles (described below), unlike solid silica particles, it is difficult to remove methanol when the methanol is trapped in the internal space of the silica particles. Therefore, a combination of these methods was used to achieve silica particles with a low methanol content.
  • silica particles and silica sol there have been no proposals to date that focus on reducing formaldehyde and the methanol content, but aim to reduce the methanol content. The present invention will be described in detail below.
  • the silica particles according to the present invention are particles containing aluminum atoms.
  • the amount of aluminum atoms present throughout the silica particles i.e., the aluminum atom content in the silica particles
  • the amount of aluminum atoms present throughout the silica particles is 120 to 50,000 ppm/ SiO2 (silica particles) in terms of Al2O3 relative to the mass of the silica particles.
  • it can be 300 to 20,000 ppm/ SiO2 , or 500 to 20,000 ppm/ SiO2 , or 500 to 10,000 ppm / SiO2 , or 500 to 5,000 ppm/ SiO2 , or 500 to 1,000 ppm/ SiO2 .
  • the amount of aluminum atoms present in the entire silica particles is expressed as "ppm/SiO 2 " as a unit showing the amount relative to the mass (g) of the silica particle.
  • the amount of aluminum atoms present in the entire silica particles can be determined by a dissolution method using a hydrofluoric acid aqueous solution (also called a hydrofluoric acid aqueous solution). Specifically, the silica particles are dissolved in a hydrofluoric acid aqueous solution, and the resulting solution is measured and analyzed using an ICP optical emission spectrometer, whereby the amount of aluminum atoms present in the entire silica particles can be expressed in terms of Al2O3 . More specifically, the silica sol is first dried to remove the dispersant, obtaining silica particles.
  • aqueous solution of hydrofluoric acid e.g., a mixture of 2.5 ml of nitric acid and 2.5 ml of 38% hydrofluoric acid
  • hydrofluoric acid e.g., a mixture of 2.5 ml of nitric acid and 2.5 ml of 38% hydrofluoric acid
  • the amount of aluminum atoms in the aqueous solution is measured using an ICP emission spectrometer to obtain the aluminum atom content (ppm) converted to Al2O3 .
  • This is then divided by the mass of the silica particles to obtain the amount of aluminum atoms present in the entire silica particles ( Al2O3 ( ppm )/ SiO2 ).
  • the aluminum atoms may exist as aluminosilicate.
  • the silica particles have aluminosilicate formed at least on the surface of the particles, and aluminosilicate may be formed not only on the particle surface but also inside the silica particles.
  • the "particle surface” can be defined as a region from which an aluminum compound can be eluted by a leaching method using a mineral acid
  • the "particle interior” can be defined as a region other than the elutable region.
  • the silica particles are hollow silica particles described later
  • the "particle interior” can refer to the deep part of the silica (SiO 2 )-containing outer shell of the hollow silica particles or the inner part of the outer shell (the part in contact with the internal space).
  • the leaching method uses an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid to elute aluminum atoms (which may be present as aluminosilicates (hereinafter also referred to as aluminum compounds)) onto the surface of target silica particles. More specifically, the dispersant from the target organosilica sol is first removed by evaporation or other methods, followed by heating and drying. The resulting silica gel is then ground into silica powder.
  • at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid
  • aluminum compounds aluminosilicates
  • the aqueous solution of the mineral acid is added to the silica powder to leach (elute) the aluminum atoms, and the filtrate obtained by centrifugal filtration is measured for its aluminum atom content using an ICP atomic emission spectrometer to obtain the aluminum atom content (ppm) converted to Al2O3 . This is then divided by the mass of the silica powder (powdered silica particles) to determine the amount of aluminum atoms present on the silica particle surface ( Al2O3 (ppm)/ SiO2 ) converted to Al2O3 .
  • the aluminum atom-containing silica particles according to the present invention can have an amount of aluminum atoms present on the surface of the silica particles of 100 to 20,000 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles, as measured by a leaching method.
  • the ratio of the amount of aluminum atoms present on the particle surface to the amount of aluminum atoms present in the entire particle i.e., the ratio (a)/(b) of the amount of aluminum atoms (in terms of Al 2 O 3 , relative to SiO 2 ) present on the silica particle surface obtained by measurement using the aforementioned leaching method to the amount of aluminum atoms (in terms of Al 2 O 3 , relative to SiO 2 ) present in the entire silica particle obtained by measurement using the aforementioned hydrofluoric acid aqueous solution, can be set to, for example, a range of 0.001 to 1.0.
  • the aluminum atom-containing silica particles of the present invention have a methanol content of less than 800 ppm relative to the mass of the particles, preferably less than 200 ppm, less than 100 ppm, particularly preferably less than 20 ppm.
  • the aluminum atom-containing silica particles of the present invention can have a methanol content of 0.1 ppm or more, 1 ppm or more, or 5 ppm or more relative to the mass of the particles, and can be 0.1 ppm or more and less than 800 ppm, 1 ppm or more and less than 800 ppm, 1 ppm or more and less than 200 ppm, 1 ppm or more and less than 100 ppm, 1 ppm or more and less than 20 ppm, or 5 ppm or more and less than 100 ppm.
  • ppm/SiO 2 when referring to the unit of methanol content, when indicating the methanol content relative to silica particles (mass), it is referred to as "pp
  • the methanol content of aluminum atom-containing silica particles By making the methanol content of aluminum atom-containing silica particles less than 800 ppm by weight, it can reduce the amount of formaldehyde that is generated by the oxidation of methanol and released outside of particles.From the viewpoint of reducing formaldehyde, the lower the methanol content of aluminum atom-containing silica particles by weight, the better.However, by making the methanol content of the particles by weight more than 0.1 ppm, the silanol group on the surface of the particles and methanol are bonded to form methoxy group, and the dispersibility of the particles in organic solvent and organic resin can be improved.
  • the temperature at which organic solvent components are sufficiently desorbed from the silica particles can be determined, for example, by measuring the weight at 30-minute intervals while heating at a constant temperature, and adopting that temperature if the weight loss rate after heating is 0.1% by mass or less.
  • the 30-minute heating period for measuring the weight loss rate can be started at 100°C and continued by increasing the temperature in 50°C increments up to 350°C until the weight loss rate reaches 0.1% by mass or less. If the weight loss rate after heating exceeds 0.1% by mass, the silica particles may not have been sufficiently dried by heating and may still contain volatile components (such as organic solvent components), so the heating temperature must be further increased to quantify the methanol content.
  • the heating temperature is preferably in the range of 100°C to 350°C, or 150°C to 350°C, from the viewpoint of measuring the amount of methanol generated by evaporation from the silica particles at the temperature used for film formation after mixing the silica particles with the resin.
  • a maximum heating temperature of 350°C is more preferable.
  • the heating conditions can be adjusted according to the dispersing medium.
  • the heating conditions can be 100 ° C and 30 minutes; when the ⁇ ° C is 150 ° C or more and less than 200 ° C, the heating conditions can be 150 ° C and 30 minutes; when the ⁇ ° C is 200 ° C or more and less than 250 ° C, the heating conditions can be 200 ° C and 30 minutes; when the ⁇ ° C is 250 ° C or more and less than 300 ° C, the heating conditions can be 250 ° C and 30 minutes; when the ⁇ ° C is 300 ° C or more and less than 350 ° C, the heating conditions can be 300 ° C and 30 minutes;
  • ⁇ Heating conditions> ⁇ boiling point of the organic solvent (° C.)+50, When 0 ⁇ 150, heating at 100°C for 30 minutes; When 150 ⁇ 200, heating at 150°C for 30 minutes; when 200 ⁇ 250, heating at 200°C for 30 minutes; when 250 ⁇ 300, heating at 250°C for 30 minutes; When 300 ⁇ 350, heating at 300°C for 30 minutes; When 350 ⁇ 400, heat at 350° C. for 30 minutes.
  • particles in which the amount of aluminum atoms present in the entire silica particles, calculated as Al 2 O 3, is 120 to 50,000 ppm/SiO 2 relative to the mass of the silica particles and the methanol content relative to the mass of the silica particles is less than 800 ppm will be referred to as aluminum atom-containing silica particles (A)
  • particles in which the amount of aluminum atoms present in the entire silica particles, calculated as Al 2 O 3 is 120 to 50,000 ppm/SiO 2 relative to the mass of the silica particles will be referred to as aluminum atom-containing silica particles (a).
  • the silica particles according to the present invention may be solid, porous, or hollow silica particles.
  • the porous silica particles are generally spherical particles with quasi-ordered pores, while the hollow silica particles have a silica (SiO 2 )-containing shell with a space inside.
  • the average primary particle diameter of the silica particles according to the present invention is expressed as a specific surface area diameter measured by a nitrogen adsorption method (BET method).
  • the silica particles are hollow silica particles
  • their specific gravity can be calculated from ⁇ 2.2 ⁇ (R1) - 2.2 ⁇ (R2) + 0.00129 ⁇ (R2) ⁇ / (R1), where (r1) is the average primary particle diameter of any 300 hollow silica particles observed with a transmission electron microscope (TEM) as described below, (r1) is the average shell thickness of the hollow silica particles, (r2) is the average primary particle diameter of the hollow silica particles, (r1) is the average shell thickness of the hollow silica particles, (r2) is the average primary particle diameter of the hollow silica particles, (r1) is the cube of the hollow silica particles, (r2) is the cube of the hollow silica particles, and (R2) is the cube of the hollow silica particles.
  • TEM transmission electron microscope
  • (R2) in the above formula can be treated as not existing, and in that case the specific gravity will be 2.2.
  • the average primary particle diameter of the silica particles in the present invention is 10 to 140 nm, and can be, for example, 10 to 100 nm, or 10 to 90 nm.
  • the specific surface area measured by the BET method can be, for example, 18 to 200 m 2 /g, or 50 to 160 m 2 /g, or 60 to 160 m 2 /g, or 70 to 160 m 2 /g, or 80 to 150 m 2 /g.
  • the average primary particle size of the aluminum atom-containing silica particles according to the present invention can also be shown by observation with a transmission electron microscope (TEM).
  • the average primary particle size as determined by TEM observation is 10 to 140 nm, and can be, for example, 10 to 100 nm, or 10 to 90 nm.
  • the silica particles are hollow silica particles, their shells can be observed with a transmission electron microscope (TEM).
  • the thickness of the shells of the hollow silica particles as observed with a transmission electron microscope can be, for example, in the range of 3.0 to 15.0 nm, or 3.0 to 12.0 nm, and preferably 3.0 to 8.0 nm.
  • the aluminum atom-containing silica particles according to the present invention can have a number density of silanol groups on the surface of the silica particles of, for example, 0.2 to 6.0 groups/nm 2 , or 0.5 to 5.0 groups/nm 2 , 0.5 to 3.0 groups/nm 2 , 0.5 to 2.0 groups/nm 2 , 0.7 to 2.0 groups/nm 2 , or 1.1 to 2.0 groups/nm 2 .
  • the number density of silanol groups on the silica particle surface to 0.2/nm2 or more , the negative charge of the silica particles increases, improving the dispersion stability of the silica particles in the dispersion medium.
  • the number density of silanol groups on the surface of silica particles can be measured, for example, by the Sears method described in "Determination of Specific Surface Area of Colloidal Silica by Titration with Sodium Hydroxide" (G. W. Sears, Jr., Analytical Chemistry, 28(12), 1981 (1956)).
  • the silica particles may have a surface charge amount (negative charge amount) calculated per 1 g of the silica particles in the range of, for example, 25 to 250 ⁇ eq/g, or 25 to 150 ⁇ eq/g, or 25 to 100 ⁇ eq/g, or 25 to 50 ⁇ eq/g, or 25 to 45 ⁇ eq/g.
  • a surface charge amount negative charge amount calculated per 1 g of the silica particles in the range of, for example, 25 to 250 ⁇ eq/g, or 25 to 150 ⁇ eq/g, or 25 to 100 ⁇ eq/g, or 25 to 50 ⁇ eq/g, or 25 to 45 ⁇ eq/g.
  • the amount of surface charge of silica particles varies depending, in part, on the amount of aluminum atoms (aluminosilicate) present in the silica particles.
  • the amount of aluminum atoms present in the entire silica particle is less than 120 ppm/SiO 2 , the stability of the silica particle tends to decrease.
  • the amount of aluminum atoms (in terms of Al 2 O 3 , relative to SiO 2 ) present in the entire silica particles is 50,000 ppm/SiO 2 or more, the particle size after doping tends to increase compared to the particle size measured by dynamic light scattering (DLS) before doping with aluminum atoms at the aqueous sol stage.
  • DLS dynamic light scattering
  • the aluminum atom-containing silica particles according to the present invention may have a carbon content measured by elemental analysis in the range of, for example, 0.1% by mass to 10.0% by mass.
  • elemental analysis a poor solvent and a good solvent are first selected for a hollow silica sol in which hollow silica particles to be measured are dispersed, and the hollow silica particles are separated from organic components not bonded to the hollow silica particles using a centrifuge or the like. The resulting mixture is then dried to remove even adsorbed water, thereby preparing a measurement sample.
  • the obtained measurement sample of silica particles is measured using an elemental analyzer to obtain the carbon content (%) in the sample.
  • the refractive index of the aluminum atom-containing silica particles according to the present invention can be in the range of, for example, 1.20 to 1.45, or 1.20 to 1.40, or 1.20 to 1.30.
  • the aluminum atom-containing silica particles may be at least partially coated with a silane compound.
  • coated with a silane compound refers to an embodiment in which the surface of a silica particle is coated with a silane compound, and also includes an embodiment in which a silane compound is bonded to the surface of a silica particle.
  • the "embodiment in which the surface of the silica particles is coated with a silane compound” may refer to an embodiment in which at least a portion of the surface of the silica particles is coated with a silane compound, i.e., it includes an embodiment in which the silane compound covers a portion of the surface of the silica particles and an embodiment in which the silane compound covers the entire surface of the silica particles. This embodiment does not require bonding between the silane compound and the surface of the silica particles.
  • an embodiment in which a silane compound is bonded to the surface of a silica particle means an embodiment in which a silane compound is bonded to at least a portion of the surface of a silica particle, i.e., an embodiment in which the silane compound is bonded to a portion of the surface of a silica particle, an embodiment in which the silane compound is bonded to a portion of the surface of a silica particle and covers at least a portion of the surface, and even an embodiment in which the silane compound is bonded to the entire surface of a silica particle and covers the entire surface. That is, the silane compound can function as a surface modifier for the aluminum atom-containing silica particles.
  • the silane compound may be at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2).
  • R 1 is a group bonded to a silicon atom, and each R 1 independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si-C bond, or a combination of these groups;
  • R2 is a group or atom bonded to the silicon atom, and independently represents an alkoxy group, an acyloxy group, a hydroxy group, or a halogen atom, or a combination of these groups or atoms; a represents an integer of 1 to 3.
  • the term "independently from each other” means that multiple groups can each independently represent the groups defined as options. That is, for example, in formula (1), when there are two or more R 1s (a is 2 to 3), the multiple R 1s may be the same group (e.g., all methyl groups) or a combination of different groups (when a is 2, for example, a methyl group and a phenyl group, or a methyl group and a (meth)acryloylpropyl group).
  • R 3 is a group bonded to a silicon atom, and each R 3 independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si-C bond, or a combination of these groups; R4 is a group or atom bonded to the silicon atom, and independently represents an alkoxy group, an acyloxy group, a hydroxy group, or a halogen atom, or a combination of these groups or atoms; Y is a group or atom bonded to the silicon atom and represents an alkylene group, an NH
  • alkyl groups include linear or branched alkyl groups having 1 to 18 carbon atoms and cyclic alkyl groups having 3 to 10 carbon atoms. Examples include, but are not limited to, methyl groups, ethyl groups, linear, branched, or cyclic propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, and decyl groups.
  • the halogenated alkyl group is an alkyl group substituted with one or more halogen atoms, and specific examples of such alkyl groups are the same as those mentioned above, i.e., linear or branched alkyl groups having 1 to 18 carbon atoms and cyclic alkyl groups having 3 to 10 carbon atoms.
  • the halogen atom include a fluorine atom (for example, as a trifluoropropyl group), a chlorine atom, a bromine atom, and an iodine atom.
  • the above-mentioned alkenyl group may be, for example, an alkenyl group having 2 to 10 carbon atoms, and may be linear, branched, or cyclic. Furthermore, the position of the double bond contained in the alkenyl group is not particularly limited. Examples include, but are not limited to, ethenyl groups (vinyl groups), linear, branched, or cyclic propenyl groups, butenyl groups, pentenyl groups, and hexenyl groups.
  • the aryl group may be, for example, an aryl group having 6 to 30 carbon atoms, such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-pyrenyl group, or a 2-pyrenyl group.
  • Examples of the organic group having an epoxy group include a glycidoxymethyl group, a glycidoxyethyl group, a glycidoxypropyl group, a glycidoxybutyl group, and a 2-(3,4-epoxycyclohexyl)ethyl group.
  • the (meth)acryloyl group refers to both an acryloyl group and a methacryloyl group.
  • Examples of organic groups having a (meth)acryloyl group include a methacryloyloxymethyl group, an acryloyloxymethyl group, a methacryloyloxyethyl group, an acryloyloxyethyl group, a 3-methacryloyloxypropyl group, and a 3-acryloyloxypropyl group.
  • the methacryloyloxy group and the acryloyloxy group are also referred to as a methacryloxy group and an acryloxy group.
  • Examples of the organic group having a mercapto group include an ethyl mercapto group, a 3-mercaptopropyl group, a butyl mercapto group, a hexyl mercapto group, an octyl mercapto group, and a mercaptophenyl group.
  • Examples of the organic group having an amino group include an aminomethyl group, a 2-aminoethyl group, a 3-aminopropyl group, an N-2-(aminoethyl)-3-aminopropyl group, an N-(1,3-dimethyl-butylidene)aminopropyl group, an N-phenyl-3-aminopropyl group, an N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl group, a dimethylaminoethyl group, and a dimethylaminopropyl group.
  • Examples of the organic group having a carboxy group include a carboxymethyl group, a carboxyethyl group, a carboxypropyl group, and a carboxybutyl group.
  • protected carboxy group refers to a carboxy group protected by a protecting group used in ordinary organic synthesis reactions.
  • carboxy group generating group refers to a group in which a carboxy group is esterified or amidated with alcohols, amines, or the like.
  • a specific example of a silane compound containing a protected carboxy group and an organic group having a carboxy group generating group is a silane coupling agent having a carboxylic acid ester structure.
  • the carboxylic acid ester moiety and the alkoxysilyl group may be linked by an alkylene group or an alkylene group containing a heteroatom (nitrogen atom, oxygen atom).
  • the carboxylic acid ester moiety of the silane coupling agent is hydrolyzed to a carboxylic acid, and if the silane coupling agent contains a nitrogen atom (heteroatom), it is hydrolyzed to an amino acid due to the presence of a carboxy group and an amino group. Therefore, the silane coupling agent can be used as an amino acid generator.
  • the product name X-88-475 manufactured by Shin-Etsu Chemical Co., Ltd., represented by formula (1-1), can be used.
  • alkoxy group examples include alkoxy groups having 1 to 10 carbon atoms, such as, but not limited to, methoxy, ethoxy, propoxy, and isopropoxy groups.
  • acyloxy group is a group derived by removing a hydrogen atom from the carboxy group (-COOH) of a carboxylic acid compound, and a specific example is an acyloxy group having 2 to 10 carbon atoms.
  • halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.
  • alkylene group examples include alkylene groups derived from the alkyl groups described above. Specific examples include, but are not limited to, linear, branched, or cyclic alkylene groups having 1 to 10 carbon atoms, such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decamethylene.
  • a specific example of the silane compound represented by the formula (1) is a silane compound represented by the following formula (3).
  • R5 and R6 are groups bonded to a silicon atom, and each independently represents an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 30 carbon atoms, or a (meth)acryloyl group, an alkenyl group, or an organic group having a carboxyl group-generating group, and which is bonded to a silicon atom via a Si-C bond;
  • R7 is a group bonded to a silicon atom, and independently represents an alkoxy group having 2 to 3 carbon atoms, or a combination of these groups. Specific examples of these groups include those mentioned above.
  • examples of the alkyl group having 1 to 3 carbon atoms include the alkyl groups having 1 to 3 carbon atoms mentioned above as specific examples of the alkyl group, and examples of the alkoxy group having 2 to 3 carbon atoms include the alkoxy groups having 2 to 3 carbon atoms mentioned above as specific examples of the alkoxy group.
  • silane compounds represented by the above formulas (1) and (2) include compounds represented by the following formulas:
  • R 9 and R 10 each independently represent an alkyl group having 1 to 10 carbon atoms, a hydrogen atom, or a combination of these groups
  • R 8 and R 12 each independently represent an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a group represented by formula (6)
  • R 11 independently represents an alkyl group having 1 to 10 carbon atoms or a combination of such groups
  • n represents an integer of 1 to 20
  • m represents an integer of 1 to 3.
  • a 2 , A 3 , and A 4 each independently represent a methylene group or an oxygen atom, and one of A 2 , A 3 , and A 4 represents an oxygen atom;
  • R A represents a hydrogen atom or a methyl group; * indicates a bond directly bonded to a silicon atom or a carbon atom.
  • Specific examples of these groups include those mentioned above, and examples of alkyl groups having 1 to 10 carbon atoms include the alkyl groups having 1 to 10 carbon atoms mentioned above as specific examples of alkyl groups.
  • silane compounds represented by the above formulas (1) and (2) include compounds that can form trimethylsilyl groups on the surfaces of silica particles.
  • examples of such compounds include compounds represented by the following formulas (1-2), (2-1) and (2-2).
  • R20 is an alkoxy group, such as a methoxy group or an ethoxy group.
  • Silane compounds represented by the formulas (1-2), (2-1), and (2-2) can be manufactured by Shin-Etsu Chemical Co., Ltd.
  • silane compounds represented by the above formulas (1) and (2) include, but are not limited to, the combination of a dialkoxysilane compound such as methylphenyldialkoxysilane or methyl(meth)acryloylpropyldialkoxysilane with hexamethyldisiloxane.
  • the silica particles at least partially coated with a silane compound can be obtained by adding the silane compound to a silica sol in which the silica particles are dispersed in an aqueous solvent or the like, and then heat-treating the mixture for about 0.1 to 20 hours at 10 to 95° C.
  • the amount of the silane compound added relative to the silica particles in the silica sol can be, for example, a mass ratio of silane compound/silica particles of 0.1 to 10.0.
  • the silica particles according to the present invention may be particles whose surfaces are coated with the silane compound or particles whose surfaces are bound to the silane compound at a ratio of 0.1 to 10 atoms per 1 nm2 of surface area.
  • the amount of the silane compound coated on the silica particles may be an amount such that the number of silicon atoms in the silane compound is, for example, about 0.1 to 10 atoms, or about 0.1 to 6 atoms, per 1 nm2 of the silica particle surface.
  • the treatment (reaction) of silica particles with the above-mentioned silane compound proceeds through a reaction between silanol groups generated by hydrolysis of the silane compound and hydroxyl groups (silanol groups) on the surface of the silica particles.
  • the presence of water is required for this hydrolysis, but if the silica sol is an aqueous solvent sol, the aqueous solvent can fulfill this role.
  • the silica sol is an organic solvent sol in which the aqueous medium has been replaced with an organic solvent, the water remaining in the organic solvent can fulfill this role.
  • water present in the organic solvent at 0.01 to 1% by mass can be used for the hydrolysis.
  • the hydrolysis can be carried out with or without a catalyst. If the silica particle surface is on the acidic side (pH less than 7), hydrolysis can be carried out without a catalyst.
  • a catalyst examples of the catalyst include metal chelate compounds, organic acids (acetic acid, oxalic acid, lactic acid, etc.), inorganic acids (hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc.), organic bases (heterocyclic amines, quaternary ammonium salts, sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, etc.), and inorganic bases (ammonia, sodium hydroxide, potassium hydroxide, etc.).
  • the present invention also relates to an organosol containing aluminum-atom-containing silica particles, in which the amount of aluminum atoms present in the entire silica particles is 120 to 50,000 ppm/ SiO2, calculated as Al2O3 , relative to the mass of the silica particles.
  • the methanol content in the organosol can be less than 800 ppm, for example, less than 200 ppm, less than 150 ppm, or less than 100 ppm.
  • the methanol content in the organosol can be 0.1 ppm or more, 1 ppm or more, or 5 ppm or more, and can be 0.1 ppm or more but less than 800 ppm, 1 ppm or more but less than 800 ppm, 1 ppm or more but less than 200 ppm, or 1 ppm or more but less than 100 ppm.
  • the methanol content in the sol can be measured using headspace-gas chromatography-mass spectrometry according to the aforementioned procedure.
  • the methanol content of the aluminum atom-containing silica particles contained in the sol is not particularly limited, and the silica particles may have a methanol content of less than 800 ppm.
  • the organic solvent may include a ketone, an ether, an ester, an amide, a glycol, or an alcohol having two or more carbon atoms.
  • the ketone may, for example, be a ketone having 1 to 10 carbon atoms, with aliphatic ketones being particularly preferred. Examples include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, cyclopentanone, and methyl cyclopentanone. Note that the "number of carbon atoms" in the examples of organic solvents refers to the total number of carbon atoms contained in the ketone and other compounds.
  • esters include, for example, ethers having 1 to 10 carbon atoms, and among these, aliphatic ethers are preferred. Examples include dimethyl ether, ethyl methyl ether, diethyl ether, tetrahydrofuran, and 1,4-dioxane.
  • esters include, for example, esters having 1 to 10 carbon atoms, and among these, aliphatic esters are preferably used.
  • examples include methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethyl acrylate, propyl acrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, dimethyl adipate, diethyl adipate, and dipropyl adipate.
  • amide examples include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and tetramethylurea.
  • glycol dihydric alcohol
  • examples of the glycol include methanediol, ethylene glycol, propylene glycol, and diethylene glycol.
  • Examples of the alcohol having two or more carbon atoms include alcohols having 2 to 10 carbon atoms, and among these, aliphatic alcohols are preferred.
  • the aliphatic alcohol may be any of primary, secondary, and tertiary alcohols, and it is also possible to use polyhydric alcohols such as the above-mentioned dihydric alcohols (glycols) and trihydric alcohols as the alcohols.
  • Examples of the monohydric primary alcohol include ethanol, 1-propanol, 1-butanol, and 1-hexanol.
  • Examples of the monohydric secondary alcohol include 2-propanol, 2-butanol, cyclohexanol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether.
  • the monohydric tertiary alcohol may, for example, be tert-butyl alcohol.
  • the trihydric alcohol includes glycerin.
  • the aluminum atom-containing silica particles may be at least partially coated with a silane compound.
  • the silane compound include the compounds represented by the above formulas (1) and (2), but in a preferred embodiment, silane compounds represented by the following formulas (7) and (8) can be used.
  • the silane compounds represented by the following formulas (7) and (8) do not produce methanol upon hydrolysis, and therefore can suppress the effect on the methanol content in the organosol according to the present invention.
  • R 13 is a group bonded to a silicon atom, and each R 13 is independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, or an aryl group, or represents an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group, and which is bonded to a silicon atom via a Si—C bond, or represents a combination of these groups;
  • R 14 is a group or atom bonded to a silicon atom, and independently represents an alkoxy group having 2 or more carbon atoms, an acyloxy group, a hydroxy group, or a halogen atom, or a combination of these groups or atoms; d represents an integer of 1 to 3;
  • R 14 is a group
  • the aluminum atom-containing silica particles preferably have an average particle size (DLS average particle size: Z-average particle size, harmonic mean particle size) measured by dynamic light scattering (DLS) of 15 to 200 nm, and can be, for example, in the range of 20 to 200 nm, 30 to 200 nm, or 40 to 200 nm, or 50 to 200 nm, or 50 to 180 nm, or 50 to 150 nm, or 50 to 120 nm, or 50 to 100 nm, or 100 to 200 nm, or 100 to 180 nm.
  • the DLS average particle size represents the average value of the secondary particle size (dispersed particle size), and it can be determined that the larger the DLS average particle size, the more the silica particles in the medium are in an agglomerated state.
  • the content of the aluminum atom-containing silica particles can be, for example, 1 to 70 mass %, or 5 to 40 mass %, and typically 10 to 30 mass %, based on the total amount of the organosol (100 mass %).
  • the silica particle concentration in a silica sol is a value determined by a calcination method, specifically, by calcining the target silica sol at, for example, 1000° C. for 30 minutes or more, and dividing the mass of the resulting calcination residue by the mass of the target silica sol.
  • the mass of the calcination residue is also sometimes referred to as the “silica solid content.”
  • the viscosity (25°C) of the organosol according to the present invention can be set, for example, in the range of 1.0 to 10.0 mPa ⁇ s. This viscosity can be adjusted appropriately using the organic solvent mentioned above.
  • the organosol according to the present invention may further contain a basic compound, which can adjust the pH of the organosol and the amount of surface charge. By adjusting the type and amount of the basic compound to be added, it is possible to adjust the surface charge amount of the silica particles to any desired value.
  • the surface charge amount of the silica particles in the organosol i.e., the surface charge amount (negative charge amount) calculated per gram of silica particles
  • the surface charge amount can be adjusted to 25 to 250 ⁇ eq/g, or alternatively, the surface charge amount can be set to a range of 25 to 150 ⁇ eq/g, 25 to 100 ⁇ eq/g, 25 to 50 ⁇ eq/g, or 25 to 45 ⁇ eq/g.
  • the pH of the organosol can be adjusted to, for example, 7 to 10 by adding a basic compound.
  • the basic compound can be either an inorganic base or an organic base, and can contain, for example, an amine, or an amine and ammonia.
  • the amine can be added and contained in an amount of 0.001 to 10% by mass, 0.01 to 10% by mass, or 0.1 to 10% by mass relative to the mass of the silica particles.
  • the amine may be, for example, an aliphatic amine or an aromatic amine, with aliphatic amines being preferred. At least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms can be used. These amines are water-soluble and are at least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms.
  • Examples of primary amines include monomethylamine, monoethylamine, monopropylamine, monoisopropylamine, monobutylamine, monoisobutylamine, monosec-butylamine, mono-tert-butylamine, monomethanolamine, monoethanolamine, monopropanolamine, monoisopropanolamine, monobutanolamine, monoisobutanolamine, monosec-butanolamine, and mono-tert-butanolamine.
  • secondary amines include dimethylamine, diethylamine, dipropylamine, diisopropylamine, N-methylethylamine, N-ethylisobutylamine, dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, N-methanolethylamine, N-methylethanolamine, N-ethanolisobutylamine, and N-ethylisobutanolamine.
  • tertiary amines include trimethylamine, triethylamine, tripropylamine, triisopropylamine, diisopropylethylamine, tributylamine, triisobutylamine, trisecbutylamine, tritertbutylamine, trimethanolamine, triethanolamine, tripropanolamine, triisopropanolamine, tributanolamine, triisobutanolamine, trisecbutanolamine, tritertbutanolamine, tripentylamine, 3-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl acrylate, and 2-(diethylamino)ethyl methacrylate.
  • the water solubility of the amine is preferably 80 g/L or more, or 100 g/L or more.
  • primary amines and secondary amines are preferred, with secondary amines being more preferred due to their low volatility and high solubility, such as diisopropylamine and diethanolamine.
  • Tertiary amines such as diisopropylethylamine and tripentylamine are also preferably used.
  • the pH of the organosol according to the present invention can be adjusted from acidic to alkaline.
  • the pH can be set to between 1 and less than 7 on the acidic side, and between 7 and 13 on the alkaline side.
  • the organosol can have a pH of 1 to 10, or 3 to 10. Adjustment to acidic is achieved by adding an inorganic or organic acid, and adjustment to alkaline is achieved by adding an inorganic or organic base (such as the basic compounds mentioned above).
  • the pH of the organosol is measured in the form of a sol of an organic solvent miscible with water. If the solvent is subsequently replaced with a hydrophobic organic solvent, the pH is measured in advance at the stage of a sol of a hydrophilic organic solvent such as methanol, or the pH is measured after adding a hydrophilic organic solvent to the sol of the hydrophobic solvent.
  • the dispersion medium is a hydrophilic organic solvent such as methanol sol or propylene glycol monomethyl ether sol
  • the pH can be measured using a solution prepared by mixing pure water and the sol in a mass ratio of 1:1.
  • the dispersion medium is a hydrophobic organic solvent such as methyl ethyl ketone sol
  • the pH can be measured using a solution prepared by mixing pure water, methanol, and the sol in a mass ratio of 1:1:1.
  • organosol containing the aluminum atom-containing silica particles of the present invention (hereinafter also referred to as "organosol") can be prepared by removing the solvent from the sol to form silica particles (dried product), which can then be dispersed again in an organic solvent to obtain a sol having good dispersibility (hereinafter also referred to as "redispersed organosol").
  • the initial organosol and the redispersed organosol may contain the same or different dispersion media (organic solvents), and the silica particle concentration in each organosol may be selected from the range of 1 to 70% by mass based on the total amount of the organosol (100% by mass).
  • the resulting (dried) silica particles may be pulverized to form powdered silica particles, taking into consideration their redispersibility in the subsequent organic solvent.
  • Redispersion can be achieved by, but is not limited to, a redispersion process such as stirring with a rotor or mechanical stirrer, ultrasonic vibration, or centrifugal defoaming.
  • the redispersion time is, for example, 24 hours.
  • the average particle size of the aluminum atom-containing silica particles in the redispersed organosol as determined by DLS may be within the same range as the average particle size of the particles in the initial organosol as determined by DLS.
  • the ratio of the average particle size of the sol before and after redispersion can be evaluated.
  • an organosol that satisfies ⁇ equation (X): 4 ⁇ (Pr)/(P0) ⁇ 0.5 ⁇ can be evaluated as having excellent redispersibility.
  • the initial organosol and redispersed organosol used in this evaluation are in the same solvent (dispersion medium), and the silica particle concentrations in both cases are set to 1 to 70 mass%.
  • the organosol containing aluminum-atom-containing silica particles of the present invention is produced by substituting a water-dispersed silica sol or a methanol - dispersed silica sol containing aluminum-atom-containing silica particles, the amount of aluminum atoms present in the entire silica particles being 120 to 50,000 ppm/ SiO2, calculated as Al2O3 , relative to the mass of the silica particles, with a water-soluble organic solvent other than methanol to obtain an organosol having a methanol content of less than 800 ppm.
  • the solvent substitution can be carried out, for example, by heating under reduced pressure and/or ultrafiltration.
  • the methanol content of the aluminum-atom-containing silica particles used in the production of this organosol is not particularly limited, and the silica particles may have a methanol content of less than 800 ppm relative to their mass.
  • the water-soluble organic solvent other than methanol can be appropriately selected from the organic solvents listed above under "Organosol" that meet the conditions.
  • the water-soluble organic solvent can be selected based on whether it is miscible with 5% by mass of pure water (i.e., does not undergo phase separation).
  • a water-soluble organic solvent having 2 to 10 carbon atoms or 2 to 6 carbon atoms can be selected, and examples of the water-soluble organic solvent having 2 to 10 carbon atoms include, but are not limited to, ethanol, propanol, isopropanol, butanol, 1,2-dibutanol, 1,3-dibutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, ⁇ -butyrolactone, 1,4-dioxane, tetrahydrofuran, dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, pyridine, ethyl lactate, 1,3-dimethyl-2-imidazolidinone
  • two or more water-soluble organic solvents may be mixed and selected.
  • these water-soluble organic solvents from the viewpoints of odor and ease of solvent substitution, ethanol, propanol, isopropanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether are desirable, and propanol, isopropanol, and propylene glycol monomethyl ether are more desirable.
  • a process can be carried out in which the surface of the aluminum atom-containing silica particles is treated with at least one silane compound selected from the group consisting of compounds represented by formula (1) and formula (2), particularly with at least one silane compound selected from the group consisting of compounds represented by formula (7) and formula (8).
  • this step may be carried out by adding the silane compound to an aqueous sol or organic solvent sol containing aluminum atom-containing silica particles, followed by heating and stirring at 10°C to 95°C for 0.1 to 20 hours.
  • the step of adding the silane compound and heating and stirring may be carried out multiple times, for example, 2 to 10 times, 2 to 8 times, 2 to 5 times, or 3 to 5 times.
  • a step of adding a basic compound to increase the pH by 0.1 to 7 may be included.
  • the basic compound to be added may be either an organic base or an inorganic base, and those listed above under [Basic Compound] can be used.
  • the method may include a step of substituting the water-soluble organic solvent with an organic solvent having a higher boiling point than the water-soluble organic solvent used in the solvent substitution step, containing nitrogen atoms and/or oxygen atoms, and having a boiling point of 200 to 300°C or lower.
  • the organic solvent having a nitrogen atom and/or an oxygen atom can be appropriately selected from the organic solvents listed above in the section [Organosol] so as to meet the conditions.
  • the solvent substitution can be carried out by heating under reduced pressure, for example, at a pressure of about 10 to 600 Torr and at a temperature of about 30 to 200°C.
  • the silane compound addition/heating and stirring step (a step of treating the surfaces of aluminum-atom-containing silica particles with a silane compound), the basic compound addition step (pH increase step), and the substitution step with an organic solvent having nitrogen atoms and/or oxygen atoms are optional, and can be performed in any order in combination with the solvent substitution step by heating under reduced pressure and/or ultrafiltration, each multiple times, for example, 2 to 10 times, 2 to 8 times, 2 to 5 times, or 3 to 5 times.
  • the aluminum atom-containing silica particles (A) according to the present invention having a methanol content of less than 800 ppm relative to the mass of the silica particles, can be produced by a process comprising heating an organosol containing the aluminum atom-containing silica particles (a) and an organic solvent at 50°C to 200°C under reduced pressure to remove the solvent and obtain silica particles.
  • the reduced pressure condition can be about 10 to 600 Torr.
  • the aluminum atom-containing silica particles (A) are particles having a low methanol content (particles with a low methanol content ) in which the amount of aluminum atoms present in the entire particle is 120 to 50,000 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles, and the methanol content relative to the mass of the silica particles is less than 800 ppm.
  • the aluminum atom-containing silica particles (a) may be any particles in which the amount of aluminum atoms present in the entire particle is 120 to 50,000 ppm/ SiO2 , calculated as Al2O3 , relative to the mass of the silica particles, and the methanol content of the particles (a) is not particularly limited.
  • the silica particles (A) can be made into particles with an even lower methanol content by undergoing this step.
  • the organic solvent can be appropriately selected from the organic solvents listed above in the section [Organosol].
  • the low-methanol-content silica particles (A) obtained in this process can be mixed with an organic solvent to obtain an organosol with a methanol content of less than 800 ppm.
  • This organic solvent can also be appropriately selected from the organic solvents listed above under [Organosol].
  • the organosol containing the aluminum atom-containing silica particles (a) and an organic solvent is produced by heating a water-dispersed silica sol containing aluminum atom-containing silica particles (a) under reduced pressure and/or by substituting the organic solvent by ultrafiltration or heating under reduced pressure.
  • the aluminum atom-containing silica particles (a) are solid silica particles
  • a water-dispersed silica sol containing the particles can be produced by the following method.
  • a water-dispersed sol of aluminum atom-containing solid silica particles (a1) can be obtained by subjecting an aqueous alkali silicate solution containing aluminum atoms, or an aqueous alkali silicate solution to which aluminum atoms have been added as an aluminate, to cation exchange, and heating the resulting activated silicic acid containing aluminate ions at 80 to 300°C.
  • the aluminate include sodium aluminate and potassium aluminate.
  • the aqueous alkali silicate solution include an aqueous sodium silicate solution and an aqueous potassium silicate solution.
  • the aqueous alkali silicate solution containing the aluminate can be obtained by adding a 0.1 to 30 mass % aqueous solution of the aluminate to an aqueous alkali silicate solution at a temperature of 20 to 100°C and stirring for 0.1 to 24 hours.
  • Cation exchange is carried out by contacting the aqueous solution of interest with a strongly acidic cation exchange resin in H form. After cation exchange, the aqueous solution can be contacted with an anion exchange resin, if necessary.
  • the activated silicic acid containing aluminate ions thus produced can be heated at 80 to 300°C for, for example, 0.1 to 24 hours to obtain a water-dispersed silica sol containing silica particles in which aluminosilicate sites are formed on the surface and inside of solid silica particles.
  • the aqueous dispersion sol of aluminum atom-containing solid silica particles (a1) can be obtained by adding aluminum atoms as an aluminate or separately adding aluminum atom-containing solid silica particles to an aqueous silica sol, and then heating the aqueous silica sol at 80 to 300° C.
  • the aqueous silica sol to which the aluminate is added is, so to speak, the aqueous silica sol of the raw material, that is, an aqueous sol containing silica particles that do not contain aluminum atoms (however, aluminum atoms are allowed to be contained at an impurity level).
  • aluminate examples include sodium aluminate and potassium aluminate, and these aluminates can be added to the aqueous silica sol (raw material) as a 0.1 to 30 mass % aqueous solution.
  • the aqueous silica sol (raw material) containing aluminate ions thus obtained is heated at 80 to 300°C for, for example, 0.1 to 24 hours to obtain a water-dispersed silica sol containing silica particles in which aluminosilicate sites are formed at least on the surface of the solid silica particles, or on the surface and inside thereof.
  • a water-dispersed silica sol containing the particles can be produced by the following steps.
  • Step (ii) is a step of adding an aluminum compound to the aqueous sol prepared in step (i) in a proportion of 0.0001 to 0.5 g, calculated as Al 2 O 3 , relative to the mass of the hollow silica particles, and maintaining the mixture at 40 to 260°C for 0.1 to 24 hours to obtain an aluminum atom-containing hollow silica aqueous sol (a2).
  • the hollow silica particles constituting the aqueous sol containing hollow silica particles (also referred to as hollow silica aqueous sol) prepared in step (i) have an outer shell containing silica and have a space inside the outer shell.
  • the "hollow silica particles" prepared in step (i) are, so to speak, raw material hollow silica particles, i.e., hollow silica particles that do not contain aluminum atoms (however, aluminum atoms are allowed to be contained at an impurity level).
  • the raw material hollow silica particles are obtained by forming a silica-based shell on the surface of a core portion, called a template, in an aqueous dispersion medium, and then removing the core portion (template).
  • the template can be made of either an organic material (e.g., hydrophilic organic resin particles such as polyethylene glycol, polystyrene, or polyester) or an inorganic material (e.g., hydrophilic inorganic compound particles such as calcium carbonate or sodium aluminate).
  • the aqueous sol containing hollow silica particles as the raw material prepared in step (i) can be any of a non-hydrothermally treated hollow silica aqueous sol, a hydrothermally treated hollow silica aqueous sol, or a mixture thereof.
  • the non-hydrothermally treated hollow silica aqueous sol is an aqueous sol of hollow silica particles that has been treated in an aqueous medium via a heating temperature of less than 100°C, for example, from 20°C to less than 100°C, or from 40°C to less than 100°C, or from 50°C to less than 100°C.
  • the hydrothermally treated hollow silica aqueous sol is an aqueous sol of hollow silica particles that has been treated in an aqueous medium via a heating temperature of from 100°C to 240°C, or from 110°C to 240°C.
  • the raw material hollow silica aqueous sol (non-hydrothermally treated hollow silica aqueous sol, hydrothermally treated hollow silica aqueous sol, or a mixture thereof) can be in a form in which the raw material hollow silica particles in the aqueous sol contain aluminum atoms in the step (ii) described below, specifically in a form in which aluminosilicate sites are formed on the outer shells of the hollow silica particles.
  • the raw material hollow silica aqueous sol can be selected so that aluminum atoms are present on the surface of the raw material hollow silica particles in a ratio of 120 to 50,000 ppm/ SiO2 (based on the mass of the hollow silica particles) in terms of Al2O3 , as measured by the so-called leaching method using a mineral acid.
  • step (ii) an aluminum compound is added to the raw material hollow silica aqueous sol prepared in step (i) above, followed by heating and maintaining to obtain an aluminum atom-containing hollow silica aqueous sol.
  • the aluminum compound acts on the raw material hollow silica particles from the outside (i.e., impregnation), causing aluminum atoms to be present on the surfaces of the hollow silica particles, i.e., forming aluminosilicate sites at least on the surfaces of the particles.
  • hollow silica particles obtained material after their formation
  • step (ii) it is preferable to impregnate the hollow silica particles with the aluminum compound so that the amount of aluminum atoms (in terms of Al 2 O 3 ) present throughout the hollow silica particles is in the above-mentioned specific ratio, as measured by the dissolution method using an aqueous hydrofluoric acid solution.
  • the aluminum compound used in step (ii) can be added in an amount of 0.0001 to 0.5 g, or 0.001 to 0.1 g, or 0.001 to 0.05 g, calculated as Al 2 O 3, relative to the mass of the hollow silica particles in the hollow silica aqueous sol.
  • the heating temperature in step (ii) is 40 to 260°C, or 50 to 260°C, or 60 to 240°C.
  • the heating temperature can be 40 to less than 100°C, or 50 to less than 100°C, or 60 to less than 100°C in the case of a non-hydrothermal treatment, and 100 to 260°C, or 150 to 240°C in the case of a hydrothermal treatment.
  • the heating time in step (ii) can be in the range of 0.1 to 48 hours, or 0.1 to 24 hours, or 0.1 to 10 hours, or 1 to 10 hours.
  • the aluminum compound includes at least one aluminum compound selected from the group consisting of aluminates, aluminum alkoxides, and hydrolysates thereof.
  • the aluminates include sodium aluminate, potassium aluminate, calcium aluminate, magnesium aluminate, ammonium aluminate, and amine aluminate.
  • the aluminum alkoxides include aluminum isopropoxide and aluminum butoxide.
  • the aluminum compound can be added to the hollow silica aqueous sol in the form of a solid or an aqueous solution, with the aqueous solution being preferred.
  • the concentration of the aluminum compound in the aqueous solution can be in the range of 0.01 to 20% by mass, 0.1 to 10% by mass, or 0.5 to 5% by mass.
  • the aluminum compound can be added while stirring the hollow silica aqueous sol. The addition may be completed before the heating, may be started before the heating and completed during the heating, or may be continued throughout the entire heating period.
  • the aqueous dispersion sol containing aluminum atom-containing silica particles (a) obtained by the above method may be subjected to a step of adding sulfuric acid to the aqueous sol and maintaining the sol at a predetermined temperature (a so-called leaching step) in order to dissolve into the liquid the aluminum atom-containing components that were not doped on the surface or inside of the silica particles and the metal impurities contained in the particles.
  • This step may be carried out by, for example, adding sulfuric acid in a proportion of about 1 ppm to 5000 ppm relative to the mass of the particles in the sol, and then maintaining the sol at 5 to 100°C for 0.1 to 48 hours.
  • the method may include a step of contacting the aqueous sol containing the aluminum atom-containing silica particles (a) with a cation exchange resin or an anion exchange resin before or after the addition of sulfuric acid and holding at a predetermined temperature, in order to remove metal-containing components remaining in the system, metal-containing components eluted into the liquid by the addition of sulfuric acid, and impurity basic components such as counter ion components eluted by the added sulfuric acid and affecting the stability of the sol.
  • the pH of the aqueous sol can be adjusted to 2-5, 2-4, or 2-3.
  • the silica particle concentration can be adjusted to 5 to 50% by mass, or 10 to 30% by mass, using an evaporator or an ultrafiltration device.
  • a step of treating the surfaces of the aluminum atom-containing silica particles with at least one silane compound selected from the group consisting of compounds represented by formula (1) and formula (2), particularly at least one silane compound selected from the group consisting of compounds represented by formula (7) and formula (8) can be carried out using the heating and stirring step described above, and this step can be carried out multiple times, for example, 2 to 10 times, 2 to 8 times, 2 to 5 times, or 3 to 5 times, as desired.
  • the water-dispersed sol containing the aluminum atom-containing silica particles (a) thus obtained can be converted into an organosol by a step of substituting an organic solvent by ultrafiltration or heating under normal pressure.
  • organic solvent include the organic solvents listed above in the section on [Organosol].
  • the pressure reduction conditions can be about 10 to 600 Torr, and the heating conditions can be about 30 to 200°C.
  • the conversion from an aqueous sol to a hydrophobic organic solvent sol can be achieved by solvent-substituting the aqueous medium with a hydrophilic organic solvent (such as an alcohol), followed by further solvent-substituting with a hydrophobic organic solvent, and moisture may remain during this process.
  • a hydrophilic organic solvent such as an alcohol
  • the residual moisture content in an alcohol sol of aluminum-atom-containing silica particles may be about 0.1 to 3.0% by mass, or about 0.1 to 1.0% by mass
  • the residual moisture content in an organic solvent sol of aluminum-atom-containing silica particles (wherein the dispersion medium is an organic solvent other than alcohol) may be about 0.01 to 0.5% by mass.
  • the present invention also relates to a resin composition comprising the organosol and an organic resin component.
  • the aluminum atom-containing silica particles can account for, for example, 1% by mass to 90% by mass
  • the organic resin component can account for, for example, 99% by mass to 10% by mass, based on the total solid content (100% by mass in total).
  • the solid content in the resin composition refers to all components other than the solvent, and can be the value calculated from the residue obtained by heating the resin composition at a temperature of about 200 to 300°C to remove the solvent.
  • this specification also discloses as subject matter of the invention an embodiment of a resin composition containing the aluminum atom-containing silica particles (A) (methanol content: less than 800 ppm/SiO 2 ) and an organic resin component, and an embodiment of a resin composition containing the aluminum atom-containing silica particles obtained by removing the dispersant from the organosol (methanol content: less than 800 ppm/sol) and an organic resin component.
  • A aluminum atom-containing silica particles
  • the resin composition can be produced by mixing the organosol with an organic resin component. Furthermore, when preparing the resin composition, an organic solvent can be further added as needed to achieve uniform mixing and dispersion of the components, and after achieving uniform mixing and dispersion, the organic solvent can be distilled off as needed to adjust the aluminum atom-containing silica particles and organic resin components to the desired concentrations.
  • organic resin component examples include (meth)acrylic compounds, polyfunctional (meth)acrylates, vinyl structure-containing compounds (vinyl-containing compounds, divinyl-containing compounds, allyl compounds, diallyl-containing compounds, styrene, ethylene, propylene, and cyclic olefin-containing compounds, etc.), isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfonyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, ester structure-containing compounds (tetracarboxylic acid anhydrides, lactone ring-containing compounds, lactide-containing compounds, etc.), bismaleimides, fluorine-containing compounds, and at least one silane compound selected from the group consisting of compounds represented by formulas (1) and (2), particularly at least one monomer selected from the group consisting of compounds represented by formulas (7) and (8), or a polymer
  • the organic resin component may be, for example, a thermosetting or photocurable resin material (curable resin).
  • curable resin examples include, but are not limited to, styrene-based resins, epoxy-based resins, thioepoxy resins, novolac-based resins, cyanate-based resins, phenol-based resins, acrylic-based resins, maleimide-based resins, polyester-based resins, urethane-based resins, polyurea resins, polyimide-based resins, polyamide-based resins, polyamic acid resins, polyhydroxyimide resins, polybenzoxazole resins, polybenzimidazole resins, polybenzothiazole resins, polyhydroxyamide resins, polyhydroxyazomethine resins, polyether-based resins, polybenzoxazine resins, polytetrafluoroethylene-based resins, cycloolefin polymer-based resins, unsaturated polyester-based resins, vinyl triazine-based
  • the resin composition of the present invention may contain various curing agents, such as an amine-based curing agent, an acid anhydride-based curing agent, a radical generator-based curing agent (thermal radical generator, photoradical generator), an acid generator-based curing agent (thermal acid generator or photoacid generator), or a base generator (thermal base generator, photobase generator), as needed, or a curing aid (organic phosphorus compound, quaternary phosphonium salt, quaternary ammonium salt, etc.). Furthermore, the resin composition of the present invention may contain conventional additives as needed.
  • various curing agents such as an amine-based curing agent, an acid anhydride-based curing agent, a radical generator-based curing agent (thermal radical generator, photoradical generator), an acid generator-based curing agent (thermal acid generator or photoacid generator), or a base generator (thermal base generator, photobase generator), as needed, or a curing aid (organic phosphorus compound, quaternary phosphonium salt
  • additives examples include surfactants (leveling agents), pigments, colorants, thickeners, adhesion promoters, sensitizers, antifoaming agents, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light resistance stabilizers, etc.), plasticizers, dissolution promoters, fillers, antistatic agents, development inhibitors (diazonaphthoquinone, etc.), etc.
  • surfactants leveling agents
  • pigments pigments
  • colorants thickeners
  • adhesion promoters sensitizers
  • antifoaming agents coatability improvers
  • lubricants stabilizers (antioxidants, heat stabilizers, light resistance stabilizers, etc.)
  • plasticizers antioxidants
  • dissolution promoters fillers
  • antistatic agents antistatic agents
  • development inhibitors diazonaphthoquinone, etc.
  • a photocurable resin composition is applied to a substrate to form a coating film, and the coating film is cured by irradiating it with light to obtain a cured product. Heating may also be performed before or after light irradiation.
  • the thermosetting organic resin component (curable resin), the curing agent (such as a thermal acid generator), and optionally the curing aid can be mixed to obtain a thermosetting varnish. Mixing can be carried out in a reaction vessel using a stirring blade or a kneader.
  • the aluminum atom-containing silica particles, organosol, and resin compositions containing the organosol according to the present invention are suitable for use in semiconductor device materials, semiconductor element materials, semiconductor resist materials, insulating film materials, copper-clad laminate materials, printed circuit board materials, printing plate materials, printing ink materials, pigments, paints, sealant materials, hard coat materials, 3D printing materials, anti-reflective film materials, automotive parts materials, electronic component materials, machine element parts, adhesive materials, battery materials, power generation materials, chargeability-imparting materials, conductivity-imparting materials, powder fluidity-imparting materials, cosmetic materials, flexible wiring materials, liquid crystal display materials, organic EL display materials, micro LED display materials, QD-EL display materials, flexible display materials, antenna materials, optical wiring materials, or sensing materials.
  • the aluminum atom-containing silica particles and organosol according to the present invention are silica particles and sol with a low methanol content, and are useful in various fields including the electronic materials field as materials that suppress the generation of formaldehyde caused by methanol.
  • thermosetting materials and photocurable materials using resin compositions containing the organosol of the present invention have characteristics such as transparency and small shrinkage upon curing, and can be used for coating or bonding electronic components, optical components (anti-reflection coatings), and precision mechanical components.
  • it can be used to bond mobile phone and camera lenses, optical elements such as light-emitting diodes (LEDs) and semiconductor lasers (LDs), liquid crystal panels, biochips, camera lenses and prisms, magnetic parts in hard disks of computers and the like, pickups in CD and DVD players (the part that captures the optical information reflected from the disc), speaker cones and coils, motor magnets, circuit boards, electronic parts, and parts inside automobile engines.
  • the present invention can also be used as a hard coating material (coating material) for surface protection of automobile bodies, lamps, electrical appliances, building materials, plastics, etc., and can be applied to, for example, automobile and motorcycle bodies, headlight lenses and mirrors, plastic lenses for eyeglasses, mobile phones, game consoles, optical films, ID cards, etc.
  • ink materials for printing on metals such as aluminum and plastics include inks for printing on cards such as credit cards and membership cards, switches on electrical appliances and office equipment, and keyboards, as well as inks for inkjet printers for CDs, DVDs, etc.
  • compositions can also be suitably used as an insulating resin for electronic materials such as anti-reflection films, semiconductor encapsulation materials, adhesives for electronic materials, printed wiring board materials, interlayer insulating film materials, and encapsulation materials for power modules, as well as an insulating resin for use in high-voltage equipment such as generator coils, transformer coils, and gas-insulated switchgears.
  • silica sols, product names, and abbreviations used are as follows: (Water-dispersed silica sol, organic solvent-dispersed silica sol) IPA-ST-ZL: Water-dispersed silica sol with an average primary particle size of 80 nm by the BET method (manufactured by Nissan Chemical Industries, Ltd., methanol content: 2% by mass, 30% by mass solid silica particle sol, amount of aluminum atoms present in the entire silica particles: 430 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles)
  • PGM-ST-ZL Water-dispersed silica sol having an average primary particle size of 80 nm by the BET method (manufactured by Nissan Chemical Industries, Ltd.; methanol content: 0 mass %, 30 mass % solid silica particle sol; amount of aluminum atoms present in the entire silica particles: 430 ppm/SiO 2 in terms of Al 2 O 3 relative
  • the concentration of silica particles in the target silica sol was calculated by placing the silica sol in a crucible, removing the solvent by heating on a hot plate, then calcining it in an electric furnace at 1000°C for 30 minutes, and weighing the calcination residue.
  • the sol prepared in each example contains sulfuric acid, an amine for adjusting the pH, etc., but the organic components such as the amine are almost completely lost by volatilization/thermal decomposition after the calcination, and the amount of these components, including sulfuric acid, added is very small, so the concentration calculated by the above method can be treated as the silica particle concentration in the silica sol.
  • pH Measurement of Water-Dispersed Silica Sol The pH of the water-dispersed silica sol was measured using a pH meter (manufactured by Toa DKK Corporation, trade name: MM-43X).
  • pH Measurement of Organic Solvent Dispersed Silica Sol The pH of the organic solvent-dispersed silica sol was measured using a pH meter (manufactured by Toa DKK Corporation, trade name: MM-43X) prepared by mixing a target sample containing the organic solvent-dispersed silica sol with methanol and pure water in a mass ratio of 1:1:1.
  • the average secondary particle size (dynamic light scattering particle size; Z-average particle size, harmonic mean particle size) measured by the DLS method was measured using a dynamic light scattering particle size analyzer (trade name: Zetasizer Nano, manufactured by Malvern Panalytical).
  • a dynamic light scattering particle size analyzer trade name: Zetasizer Nano, manufactured by Malvern Panalytical.
  • the specific surface area (S N2 ) of the hollow silica particles in the organic solvent-dispersed hollow silica sol as measured by the nitrogen adsorption method was measured by obtaining a measurement sample according to the following procedure and using the BET one-point method described above.
  • Four milliliters of the organic solvent-dispersed hollow silica sol to be measured was added to a 42-ml pear-shaped settling tube (manufactured by Thermo Fisher Scientifics, trade name: Nalgene Oak Ridge), and 4 ml of MEK and 20 ml of hexane were added. The mixture was left to stand for 5 minutes to cause cloudiness, separation, or precipitation due to aggregation.
  • the mixture was then centrifuged (temperature: 5°C, rotation speed: 20,000 rpm, time: 30 minutes) using a centrifuge (manufactured by Tomy Seiko Co., Ltd., trade name: High-Speed Refrigerated Centrifuge Suprema 21), and the supernatant was removed.
  • a centrifuge manufactured by Tomy Seiko Co., Ltd., trade name: High-Speed Refrigerated Centrifuge Suprema 21
  • Four milliliters of acetone was then added, and the precipitate formed by centrifugation was redissolved in a test tube mixer (As One Corporation, trade name: MVM-10), after which 20 mL of hexane was added.
  • the mixture was then centrifuged, and the supernatant was removed.
  • the average primary particle diameter determined by the nitrogen adsorption method was calculated using the specific surface area S N2 (m 2 /g) obtained by the nitrogen adsorption method above, converted into spherical particles, using the following formula.
  • Average primary particle size (nm) measured by nitrogen adsorption method 6002/ ⁇ specific gravity of silica particles ⁇ S N2 (m 2 /g) ⁇
  • the specific gravity of the silica particles was calculated from ⁇ 2.2 ⁇ (R1) ⁇ 2.2 ⁇ (R2) + 0.00129 ⁇ (R2) ⁇ /(R1) where (r1) is the average particle diameter of 300 randomly selected hollow silica particles observed by TEM, (r2) is the average shell thickness (thickness of the outer shell) of the hollow silica particles, (R1) is the cube of (r1), and (R2) is the cube of (r2).
  • (R2) was set to zero in the above formula, and the specific gravity was treated as 2.2.
  • the amount of aluminum in the obtained aqueous solution was measured using an ICP-OES analyzer (manufactured by Rigaku Corporation, trade name: CIROS120 EOP), and the amount of aluminum present in the entire silica particles was calculated in terms of Al2O3 (relative to the mass of the silica particles) ( Al2O3 (ppm)/ SiO2 silica particles).
  • the amount of water contained in the target silica sol was measured by Karl Fischer titration using a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd., trade name: MKA-610).
  • methanol content The methanol content of silica particles or organic solvent-dispersed silica sol was determined by heating a sample tube containing the target sample at 100°C for 30 minutes (Examples 1, 4 to 9, Comparative Examples 1 and 2), or at 150°C for 30 minutes in the cases where PGME was used (Examples 2, 3, 10 to 24), and analyzing the volatilized components using a headspace gas chromatograph mass spectrometer (HS-GCMS).
  • HS-GCMS headspace gas chromatograph mass spectrometer
  • HS-GCMS device configuration Headspace sampler: Product name 7697A (manufactured by Agilent Technologies) GC: Product name: Intuvo 9000GC System (manufactured by Agilent Technologies) MS: Product name 5977B (Agilent Technologies) Column: Product name DB-624 UI (Agilent Technologies) Heating program: Hold at 40°C for 1 minute, then heat to 260°C at 20°C/min, and hold at 260°C for 8 minutes.
  • Example 1 Preparation of low-methanol solid silica particles (IPA sol) 200 g of IPA-ST-ZL (water-dispersed solid silica particle sol: average secondary particle size by DLS method: 125 nm, pH: 3.77, water content: 1 mass%, methanol content: 2 mass%) was added to a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.6 g of pure water and 3.52 g of KBM-112 were added and heated at 60 ° C. for 3 hours. Thereafter, 2.74 g of HMDSO was added and heated at 60 ° C. for 3 hours. Thereafter, 0.04 g of DiPEA was added and heated at 60 ° C. for 1 hour.
  • IPA-ST-ZL water-dispersed solid silica particle sol: average secondary particle size by DLS method: 125 nm, pH: 3.77, water content: 1 mass%, methanol content: 2 mass%
  • the resulting sol (E1-Z) had an average secondary particle size by DLS method of 175 nm and a pH of 6.6.
  • the sol (E1-Z) was evaporated at 50°C and reduced to 60 Torr to remove the dispersion medium, yielding a silica particle powder.
  • the methanol content of this powder (silica particles) (E1-P) was 14 ppm relative to the mass of the silica particles, and the amount of aluminum atoms present in the entire silica particles was 430 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • the average secondary particle diameter of the redispersed sol (E1-ZR) measured by DLS method was 141 nm
  • Example 2 Preparation of low-methanol solid silica PGME sol 200 g of PGM-ST-ZL (water-dispersed solid silica particle sol: average secondary particle diameter by DLS method: 160 nm, pH: 3.76, water content: 1 mass%, methanol content: 120 ppm relative to the mass of silica particles, Al 2 O 3 content: 430 ppm relative to the mass of silica particles, /SiO 2 ) was added to a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.6 g of pure water and 4.28 g of KBE-112 were added and heated at 60°C for 3 hours.
  • PGM-ST-ZL water-dispersed solid silica particle sol: average secondary particle diameter by DLS method: 160 nm, pH: 3.76, water content: 1 mass%, methanol content: 120 ppm relative to the mass of silica particles, Al 2 O 3 content: 430 ppm relative to the mass of
  • the obtained sol (E2-Z) had an average secondary particle diameter of 123 nm as measured by DLS and a pH of 9.1.
  • the methanol content of this sol was 122 ppm, and the amount of aluminum atoms present in all silica particles in the sol was 430 ppm / SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 3 Preparation of low-methanol solid silica particles
  • the low-methanol solid silica PGME (E2-Z) sol obtained in Example 2 was decompressed to 100°C and 60 Torr to remove the dispersant, thereby obtaining a silica particle powder.
  • the methanol content of this powder (silica particles) (E3-P) was 16 ppm relative to the mass of the silica particles.
  • 1 g of the powder (silica particles) (E3-P) was placed in a 10 ml eggplant flask, PGME was added so that the concentration of the silica particles was 60% by mass, and the mixture was stirred with a magnetic stirrer for 2 hours.
  • Example 4 Preparation of low-methanol hollow silica IPA sol. 1,856 g of HKT-A20-40D (water-dispersed hollow silica particle sol: Ningbo Dilato Co., Ltd., trade name) was placed in a 3 L plastic container, and 32.2 g of a sodium aluminate aqueous solution diluted to a concentration of 1.0 mass% (calculated as Al 2 O 3 ) was added dropwise over 1 minute while stirring at 650 rpm using a mechanical stirrer equipped with a glass stirring blade. The mixture was then stirred at the same rotation speed for 30 minutes. An additional 643.6 g of pure water was added, and the mixture was stirred for an additional 20 minutes to obtain a mixture.
  • HKT-A20-40D water-dispersed hollow silica particle sol: Ningbo Dilato Co., Ltd., trade name
  • the resulting solution was then passed through a column packed with a cation exchange resin (product name: H-type Amberlite IR-120B) at a space velocity (SV) of 5/hour to obtain a water-dispersed sol of aluminum atom-containing hollow silica particles (A1).
  • a cation exchange resin product name: H-type Amberlite IR-120B
  • SV space velocity
  • Al2O3 space velocity
  • IPA methanol content: 6 ppm
  • UF ceramic ultrafiltration membrane manufactured by NGK Insulators, Ltd., molecular weight cutoff: 50,000.
  • the dispersion medium was replaced from water to IPA, yielding the target IPA sol (IPA-1).
  • the physical properties of the resulting IPA sol (IPA-1) were a silica particle concentration of 10 mass%, an average secondary particle diameter measured by DLS method of 66 nm, a water content of 1.8 mass%, and a methanol content of 6 ppm in the sol.
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 700 ppm/ SiO2, calculated as Al2O3 , relative to the mass of the silica particles.
  • the IPA sol (IPA-1) was heated under reduced pressure at 60°C and 100 Torr in an evaporator to remove the dispersion medium, yielding the target IPA sol (IPA-2).
  • the physical properties of the resulting IPA sol (IPA-2) were a silica particle concentration of 24% by mass, an average secondary particle diameter of 102 nm as determined by DLS, a water content of 1.8% by mass, and a methanol content of 6 ppm.
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 700 ppm/ SiO2, calculated as Al2O3 , relative to the mass of the silica particles.
  • Example 5 Preparation of low-methanol hollow silica particles 50 g of the IPA sol (IPA-2) obtained in Example 4 was added to a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.6 g of pure water and 1.27 g of KBM-112 were further added, followed by heating at 60°C for 3 hours. Thereafter, 3.43 g of HMDSO was added, followed by heating at 60°C for 3 hours. Thereafter, 0.01 g of DiPEA was further added, followed by heating at 60°C for 1 hour.
  • the obtained sol (E5-Z) had an average secondary particle diameter of 120 nm as measured by DLS and a pH of 6.7.
  • the sol (E5-Z) was heated in an evaporator at 50°C and 60 Torr under reduced pressure to remove the dispersing medium, thereby obtaining a silica particle powder (E5-P).
  • the methanol content of this powder (silica particles) was 6 ppm relative to the mass of the silica particles.
  • 1 g of the powder (silica particles) (E5-P) was placed in a 10 ml eggplant flask, IPA was added so that the concentration of the silica particles was 30% by mass, and the mixture was stirred with a magnetic stirrer for 2 hours. As a result, particles could no longer be confirmed in the system from the outside, and the Tyndall phenomenon was confirmed.
  • the amount of aluminum atoms present in the entire silica particles of the powder (silica particles) (E5-P) was 700 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles.
  • Example 6 Preparation of low-methanol hollow silica particles 200 g of the aqueous dispersion sol (A1) of aluminum atom-containing hollow silica particles obtained during the preparation of the IPA sol in Example 4 was placed in a 500 mL recovery flask. The pressure was reduced to 580 Torr using a rotary evaporator, and the solvent was replaced with MeOH while heating to 120 °C. Methanol was then added to adjust the concentration, yielding a 20 wt% MeOH dispersion sol (Me1) of aluminum atom-containing hollow silica particles. The physical properties of the obtained sol were pH 3.1, an average secondary particle diameter of 72 nm by DLS method, and a water content of 1.2 wt%.
  • MeOH-dispersed sol (Me1) was added to a 200 ml recovery flask, and while stirring with a magnetic stirrer, 4.28 g of KBM-502 was added and heated at 60 ° C. for 3 hours. Then, 2.74 g of HMDSO was added and heated at 60 ° C. for 3 hours. Then, 0.04 g of DiPEA was added and heated at 60 ° C. for 1 hour. In a rotary evaporator, the pressure was reduced to 500 Torr, and the solvent was replaced from MeOH to MEK while heating at 80 ° C.
  • MEK1 31 mass % MEK-dispersed sol
  • the obtained sol had an average secondary particle diameter of 64 nm by DLS method and a pH of 6.7.
  • MEK dispersion sol (MEK1) was evaporated at 50°C and a reduced pressure of 60 Torr to remove the dispersion medium, thereby obtaining a silica particle powder (E6-P).
  • the methanol content of this powder (silica particles) was 600 ppm relative to the mass of the silica particles.
  • the average secondary particle diameter of the redispersed sol (E6-ZR) measured by DLS method was 79 nm
  • the amount of aluminum atoms present in the entire silica particles of the powder (silica particles) (E6-P) was 700 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles.
  • Example 7 Preparation of low-methanol hollow silica IPA sol 60 g of the IPA sol (IPA-1) obtained in Example 4 was added to a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 1.07 g of DPFDEOS was further added, followed by heating at 60°C for 2 hours. Thereafter, 1.06 g of HMDSO was added, followed by heating at 60°C for 2 hours. Thereafter, 0.01 g of DiPEA was further added, followed by heating at 60°C for 1 hour.
  • the resulting sol (E7-Z) had an average secondary particle diameter of 86 nm as measured by DLS and a pH of 7.8.
  • the methanol content in this sol was 117 ppm.
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 700 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 8 Preparation of low-methanol hollow silica particles 30 g of the low-methanol hollow silica IPA sol (E7-Z) obtained in Example 7 was heated in an evaporator at 60°C under reduced pressure of 60 Torr to remove the dispersing medium, thereby obtaining a silica particle powder.
  • the methanol content of this powder (silica particles) (E8-P) was 199 ppm relative to the silica particles.
  • 1 g of the obtained silica particles (E8-P) was placed in a 10 ml eggplant flask, IPA was added so that the concentration of the silica particles was 20% by mass, and the mixture was stirred with a magnetic stirrer for 2 hours.
  • the average secondary particle diameter of the redispersed sol (E8-ZR) measured by the DLS method was 88 nm
  • the amount of aluminum atoms present in the entire silica particles of the powder (silica particles) (E8-P) was 700 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles.
  • Example 9 Preparation of low-methanol particles 60 g of the IPA sol (IPA-1) obtained in Example 4 was added to a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 0.843 g of KBE-112 was added, followed by heating at 60°C for 3 hours. Thereafter, 0.692 g of X-12-967-C was added, followed by heating at 60°C for 3 hours. Thereafter, 0.01 g of DiPEA was added, followed by heating at 60°C for 1 hour.
  • the obtained sol (E9-Z) had an average secondary particle diameter of 69 nm as measured by DLS and a pH of 4.3.
  • the sol (E9-Z) was evaporated at 60°C under reduced pressure of 50 Torr to remove the dispersion medium, thereby obtaining a silica particle powder (E9-P).
  • the methanol content of this powder (silica particles) was 185 ppm relative to the mass of the silica particles.
  • 1 g of the powder (silica particles) (E9-P) was placed in a 10 ml recovery flask, IPA was added so that the silica particle concentration was 20% by mass, and the mixture was stirred with a magnetic stirrer for 2 hours. As a result, particles could no longer be confirmed in the system from the outside, and the Tyndall effect was confirmed.
  • Example 10 Preparation of low-methanol hollow silica PGME sol (PGME-1) 1856 g of HKT-A20-40D (trade name, manufactured by Ningbo Dilato Co., Ltd.) was placed in a 3 L plastic container, and 32.2 g of a sodium aluminate aqueous solution diluted to a concentration of 1.0 mass% (calculated as Al 2 O 3 ) was added dropwise over 1 minute while stirring at 650 rpm using a mechanical stirrer equipped with a glass stirring blade. The mixture was then stirred at the same rotation speed for 30 minutes. 643.6 g of purified water was then added, and the mixture was stirred for an additional 20 minutes to obtain a mixture.
  • PGME-1 1856 g of HKT-A20-40D (trade name, manufactured by Ningbo Dilato Co., Ltd.) was placed in a 3 L plastic container, and 32.2 g of a sodium aluminate aqueous solution diluted to a concentration of 1.0
  • the resulting PGME sol (PGME-1) had a silica particle concentration of 14.9% by mass, an average secondary particle diameter of 67 nm measured by DLS , a water content of 0.5% by mass, a pH of 6.9, and a methanol content of 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 810 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 11 Preparation of low-methanol hollow silica PGME sol 70 g of the PGME sol (PGME-1) obtained in Example 10 was added to a 100 ml recovery flask, and 1.73 g of 3-TEPSA was further added while stirring with a magnetic stirrer, followed by heating at 70°C for 3 hours.
  • the obtained sol (E11-Z) had an average secondary particle diameter of 65 nm as measured by DLS and a pH of 3.5.
  • the methanol content in the sol was 47 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 810 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 12 Preparation of low-methanol hollow silica PGME sol and silica particles 30 g of the PGME sol (PGME-1) obtained in Example 10 was added to a 100 ml eggplant-shaped flask, and 0.929 g of 3-EPM was further added while stirring with a magnetic stirrer, followed by heating at 70°C for 3 hours.
  • the obtained sol (E12-Z) had an average secondary particle diameter of 65 nm as measured by DLS and a pH of 3.6.
  • the methanol content in the sol was 48 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 810 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 13 Preparation of low-methanol hollow silica particles 30 g of the low-methanol hollow silica PGME sol (E12-Z) obtained in Example 12 was heated in an evaporator at 70°C under reduced pressure of 40 Torr to remove the dispersing medium, thereby obtaining a silica particle powder.
  • the methanol content of this powder (silica particles) (E13-P) was 10 ppm relative to the silica particles.
  • 1 g of the obtained silica particles (E13-P) was placed in a 10 ml recovery flask, and PGME was added so that the concentration of the silica particles was 20% by mass. The mixture was then stirred for 24 hours using a magnetic stirrer.
  • the amount of aluminum atoms present in the entire silica particles of the powder (silica particles) (E13-P) was 810 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles.
  • Example 14 Preparation of low-methanol ion-exchanged hollow silica PGME sol (PGME-2) 1000 g of the PGME sol (PGME-1) obtained in Example 10 was added to a 2000 ml recovery flask, and 100 g of H-type cation exchange resin (manufactured by The Dow Chemical Company, trade name Amberlite IR-120B) that had been washed in advance with PGME was further added. Next, after stirring at 23°C for 5 hours, the H-type cation exchange resin was removed, and the target ion-exchanged PGME sol (PGME-2) was obtained.
  • H-type cation exchange resin manufactured by The Dow Chemical Company, trade name Amberlite IR-120B
  • the resulting ion-exchanged PGME sol (PGME-2) had a silica particle concentration of 14.9% by mass, an average secondary particle diameter of 67 nm as measured by DLS, a water content of 0.5% by mass, a pH of 3.4, and a methanol content of 66 ppm .
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 730 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 15 Preparation of low-methanol hollow PGME silica sol 70 g of the ion-exchanged PGME sol (PGME-2) obtained in Example 14 was added to a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 1.36 g of PTES was added, followed by heating at 70°C for 3 hours.
  • the resulting sol (E15-Z) had an average secondary particle diameter of 63 nm as determined by DLS, a water content of 0.5 mass%, and a pH of 3.9.
  • the methanol content in the sol was 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the resulting sol was 730 ppm/ SiO2 , calculated as Al2O3 , relative to the mass of the silica particles.
  • Example 16 Preparation of low-methanol hollow PGME silica sol 0.840 g of DMEVS was added to 30 g of the low-methanol hollow silica sol (E15-Z) obtained in Example 15, and the mixture was heated at 70°C for 3 hours. 0.01 g of TPnA was then added, and the mixture was heated at 70°C for 1 hour.
  • the resulting sol (E16-Z) had an average secondary particle diameter of 65 nm as determined by DLS, a water content of 0.5 mass%, and a pH of 8.2 .
  • the methanol content in the sol was 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 730 ppm/ SiO2, calculated as Al2O3 , relative to the mass of the silica particles.
  • Example 17 Preparation of low-methanol hollow silica particles A 100 ml eggplant-shaped flask containing 20 g of the low-methanol hollow silica sol (E16-Z) obtained in Example 16 was placed in and the pressure was reduced to 40 Torr at 70°C using an evaporator to remove the dispersant, thereby obtaining a silica particle powder. The methanol content of this powder (silica particles) (E17-P) relative to the silica particles was 21 pm. Furthermore, 1 g of the obtained silica particles (E17-P) was placed in a 10 ml recovery flask, and PGME was added so that the silica particle concentration became 20% by mass. The mixture was then stirred for 24 hours using a magnetic stirrer.
  • Example 18 Preparation of low-methanol hollow silica PGME sol 70 g of the ion-exchanged PGME sol (PGME-2) obtained in Example 14 was added to a 100 ml eggplant-shaped flask, and 1.47 g of KBE-502 was further added while stirring with a magnetic stirrer, followed by heating at 70°C for 3 hours.
  • the obtained sol (E18-Z) had an average secondary particle diameter of 66 nm measured by DLS, a water content of 0.5 mass%, and a pH of 3.9.
  • the methanol content in the sol was 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 730 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 19 Preparation of low-methanol hollow silica PGME sol 0.931 g of 3-EPM was added to 30 g of the low-methanol hollow silica PGME sol (E18-Z) obtained in Example 18, and the mixture was heated at 70°C for 3 hours.
  • the obtained sol (E19-Z) had an average secondary particle diameter of 66 nm measured by DLS, a water content of 0.5 mass%, and a pH of 3.9.
  • the methanol content in the sol was 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 730 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles.
  • Example 20 Preparation of low-methanol hollow silica particles A 100 ml recovery flask containing 20 g of the low-methanol hollow silica PGME sol (E19-Z) obtained in Example 19 was placed in and the pressure was reduced to 70°C and 40 Torr using an evaporator to remove the dispersant, yielding a silica particle powder.
  • the methanol content of this powder (silica particles) (E20-P) was 18 ppm relative to the silica particles.
  • 1 g of the obtained silica particles (E20-P) was placed in a 10 ml recovery flask, and PGME was added to adjust the silica particle concentration to 20% by mass.
  • Example 21 Preparation of low-methanol hollow silica PGME sol A low-methanol hollow PGME silica sol was prepared in the same manner as in Example 19, and 0.01 g of TPnA was further added thereto, followed by heating at 70°C for 1 hour.
  • the obtained sol (E21-Z) had an average secondary particle diameter of 66 nm measured by DLS, a water content of 0.5% by mass, and a pH of 7.6.
  • the methanol content in the sol was 66 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 730 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles .
  • Example 22 Preparation of low-methanol hollow silica particles A 100 ml recovery flask containing 20 g of the low-methanol hollow silica sol (E21-Z) obtained in Example 21 was placed in and the temperature was reduced to 60°C and 50 Torr using an evaporator to remove the dispersant, thereby obtaining a silica particle powder.
  • the methanol content of this powder (silica particles) (E22-P) was 14 ppm relative to the silica particles.
  • 1 g of the obtained silica particles (E22-P) was placed in a 10 ml recovery flask, and PGME was added so that the silica particle concentration became 20% by mass. The mixture was then stirred for 24 hours using a magnetic stirrer.
  • the amount of aluminum atoms present in the entire silica particles of the powder (silica particles) (E22-P) was 730 ppm/SiO 2 in terms of Al 2 O 3 relative to the mass of the silica particles.
  • Example 23 Preparation of low-methanol hollow PGME silica sol 120 g of the ion-exchanged PGME sol (PGME-2) obtained in Example 14 was added to a 200 ml eggplant-shaped flask, and 2.83 g of KBE-503 was further added while stirring with a magnetic stirrer, followed by heating at 70°C for 3 hours.
  • the obtained sol (E23-Z) had an average secondary particle diameter of 65 nm measured by DLS, a water content of 0.5% by mass, and a pH of 3.8.
  • the methanol content in the sol was 190 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 730 ppm/ SiO2 in terms of Al2O3 relative to the mass of the silica particles .
  • Example 24 Preparation of low-methanol hollow silica PGME sol (PGME-3) 1,856 g of HKT-A20-40D (trade name, manufactured by Ningbo Dilato Co., Ltd.) was placed in a 3 L plastic container, and 32.2 g of a sodium aluminate aqueous solution diluted to a concentration of 1.0 mass% (calculated as Al 2 O 3 ) was added dropwise over 1 minute while stirring at a rotation speed of 650 rpm using a mechanical stirrer equipped with a glass stirring blade. The mixture was then stirred at the same rotation speed for 30 minutes. 643.6 g of purified water was then added, and the mixture was stirred for an additional 20 minutes to obtain a mixture.
  • PGME-3 1,856 g of HKT-A20-40D (trade name, manufactured by Ningbo Dilato Co., Ltd.) was placed in a 3 L plastic container, and 32.2 g of a sodium aluminate aqueous solution diluted
  • the dispersion medium was replaced from water to PGME, yielding the target PGME sol (PGME-3).
  • the physical properties of the obtained PGME sol (PGME-3) were: silica particle concentration 10% by mass, average secondary particle diameter measured by DLS: 67 nm, water content 0.6% by mass, pH 5.9, and methanol content in the sol 88 ppm.
  • the amount of aluminum atoms present in all silica particles in the obtained sol was 810 ppm/ SiO2 , calculated as Al2O3 , relative to the mass of the silica particles.
  • Example 25 Resin composition containing low-methanol particles and epoxy resin 10 g of the particles (E1-P) obtained in Example 1 was placed in a 100 ml recovery flask, and 40 g of epoxy resin (trade name: Celloxide 2021P, manufactured by Daicel Corporation) was added thereto and stirred with a magnetic stirrer for 2 hours. No sediment was observed visually in the resulting mixture. The mixture was then left to stand for 10 days, but no sediment was observed. In addition, filtration was performed without clogging using a 5 ⁇ m diameter nylon filter (trade name: MemBrane-Solutions, LLC) to obtain the desired low-methanol particle and epoxy resin mixed resin composition.
  • a 5 ⁇ m diameter nylon filter trade name: MemBrane-Solutions, LLC
  • Example 26 Resin composition containing low-methanol particles and acid anhydride
  • 10 g of the particles (E3-P) obtained in Example 3 was placed in a 100 ml recovery flask, and 40 g of acid anhydride Rikacid MH-700 (manufactured by New Japan Chemical Co., Ltd.) was added, followed by stirring with a magnetic stirrer for 2 hours. No sediment was observed visually in the resulting mixture. The mixture was then left to stand for 10 days, but no sediment was observed.
  • filtration was performed without clogging using a 5 ⁇ m diameter nylon filter (trade name, manufactured by MemBrane-Solutions, LLC), to obtain the desired low-methanol particle and acid anhydride mixed resin composition.
  • Comparative Example 1 Preparation of Sol 200 g of PGM-ST-ZL (average secondary particle diameter by DLS method: 160 nm, pH: 3.76, water content: 1 mass%, methanol content: 120 ppm relative to silica particles) was added to a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.6 g of pure water and 3.7 g of KBM-112 were added and heated at 60 ° C. for 3 hours. Thereafter, 2.74 g of HMDSO was added and heated at 60 ° C. for 3 hours. Thereafter, 0.04 g of DiPEA was added and heated at 60 ° C. for 1 hour.
  • the obtained PGME sol had an average secondary particle diameter of 120 nm by DLS method and a pH of 7.0.
  • the methanol content of this PGME sol was 1000 ppm or more.
  • Comparative Example 2 The methanol content of the 20 mass % MEK dispersion sol (MEK1) of aluminum atom-containing hollow silica particles obtained as an intermediate in Example 6 was measured, and the result was that the methanol content of this sol was 1000 ppm or more.
  • compositions and physical properties of the silica particles obtained in the examples and comparative examples are shown in Table 1 (Table 1-1, Table 1-2, hereinafter the same).
  • a " ⁇ " in the "Methoxy Elimination” column indicates that methoxy elimination originated from the silane compound
  • "None” indicates that there was no methoxy elimination originating from the silane compound or that no silane compound was added
  • a "None” in the “Amine” column indicates that no amine was added
  • a "No data” in other columns indicates that data was not obtained
  • a "-” indicates that the corresponding form (organosol, particles, redispersible sol, etc.) was not prepared and data was not obtained.
  • the methanol content in the sol could be reduced to 6 to 122 ppm by treating silica sol dispersed in a solvent with a low methanol content with a surface treatment agent that does not have a leaving group that converts to methanol (Examples 2, 7, 11, 12, 15, 16, 18, 19, and 21), or by using ultrafiltration (Examples 4 and 24). Furthermore, the silica sol of Example 7, which was treated with a surface treatment agent having no leaving group that converts to methanol after reducing the methanol content in the sol by ultrafiltration, and the silica particles of Example 8, which were powdered by heating under reduced pressure, also showed a low methanol content of less than 200 ppm.
  • the sol of Comparative Example 1 obtained by treating the silica particles with a surface treatment agent having a leaving group that converts the silica particles to methanol had a methanol content of 1000 ppm or more because methanol derived from the leaving group remained in the solvent.

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Abstract

[Problème] Fournir : des particules de silice et un sol de silice présentant une teneur en méthanol réduite ; et un procédé de production associé. [Solution] Sont prévus : des particules de silice contenant des atomes d'aluminium, les particules de silice étant caractérisées en ce que la quantité d'atomes d'aluminium présents dans la totalité des particules de silice est comprise entre 120 et 50 000 ppm/SiO2 par rapport à la masse des particules de silice en termes d'Al2O3, et la teneur en méthanol par rapport à la masse des particules de silice est inférieure à 800 ppm ; et un organosol contenant lesdites particules de silice.
PCT/JP2025/016668 2024-05-02 2025-05-02 Particules de silice à faible teneur en méthanol et organosol, et procédé de production associé Pending WO2025230016A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08169709A (ja) * 1994-08-05 1996-07-02 Nissan Chem Ind Ltd シリカプロパノールゾルの製造法
JP2003081626A (ja) * 2001-05-17 2003-03-19 Degussa Ag 酸化アルミニウムによりドープされ、熱分解により製造された二酸化ケイ素をベースとする粒体、その製造方法およびその使用
JP2004143028A (ja) * 2002-08-28 2004-05-20 Nippon Aerosil Co Ltd アルミナドープ疎水化シリカ微粒子
JP2010189268A (ja) * 1998-12-21 2010-09-02 Jgc Catalysts & Chemicals Ltd 微粒子、微粒子分散ゾルおよび被膜付基材
JP2012140286A (ja) * 2010-12-28 2012-07-26 Jgc Catalysts & Chemicals Ltd 新規シリカ系中空微粒子、透明被膜付基材および透明被膜形成用塗料
WO2022097694A1 (fr) * 2020-11-04 2022-05-12 日産化学株式会社 Sol de silice contenant de l'aluminium dispersé dans un solvant contenant de l'azote, et composition de résine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08169709A (ja) * 1994-08-05 1996-07-02 Nissan Chem Ind Ltd シリカプロパノールゾルの製造法
JP2010189268A (ja) * 1998-12-21 2010-09-02 Jgc Catalysts & Chemicals Ltd 微粒子、微粒子分散ゾルおよび被膜付基材
JP2003081626A (ja) * 2001-05-17 2003-03-19 Degussa Ag 酸化アルミニウムによりドープされ、熱分解により製造された二酸化ケイ素をベースとする粒体、その製造方法およびその使用
JP2004143028A (ja) * 2002-08-28 2004-05-20 Nippon Aerosil Co Ltd アルミナドープ疎水化シリカ微粒子
JP2012140286A (ja) * 2010-12-28 2012-07-26 Jgc Catalysts & Chemicals Ltd 新規シリカ系中空微粒子、透明被膜付基材および透明被膜形成用塗料
WO2022097694A1 (fr) * 2020-11-04 2022-05-12 日産化学株式会社 Sol de silice contenant de l'aluminium dispersé dans un solvant contenant de l'azote, et composition de résine

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