WO2022163600A1 - 中空粒子 - Google Patents

中空粒子 Download PDF

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Publication number
WO2022163600A1
WO2022163600A1 PCT/JP2022/002494 JP2022002494W WO2022163600A1 WO 2022163600 A1 WO2022163600 A1 WO 2022163600A1 JP 2022002494 W JP2022002494 W JP 2022002494W WO 2022163600 A1 WO2022163600 A1 WO 2022163600A1
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Prior art keywords
hollow particles
mass
parts
hollow
particles
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PCT/JP2022/002494
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English (en)
French (fr)
Japanese (ja)
Inventor
真司 渡邉
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Zeon Corp
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Zeon Corp
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Application filed by Zeon Corp filed Critical Zeon Corp
Priority to US18/272,429 priority Critical patent/US12215178B2/en
Priority to CN202280011028.8A priority patent/CN116745027B/zh
Priority to KR1020237023949A priority patent/KR20230132462A/ko
Priority to EP22745821.3A priority patent/EP4286423A4/en
Priority to JP2022578383A priority patent/JP7798041B2/ja
Publication of WO2022163600A1 publication Critical patent/WO2022163600A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/10—Esters
    • C08F222/1006—Esters of polyhydric alcohols or polyhydric phenols
    • C08F222/102—Esters of polyhydric alcohols or polyhydric phenols of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F22/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides or nitriles thereof
    • C08F22/10—Esters
    • C08F22/1006—Esters of polyhydric alcohols or polyhydric phenols, e.g. ethylene glycol dimethacrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
    • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
    • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/06—Making microcapsules or microballoons by phase separation
    • B01J13/14—Polymerisation; cross-linking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/06—Making microcapsules or microballoons by phase separation
    • B01J13/14—Polymerisation; cross-linking
    • B01J13/16—Interfacial polymerisation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/06—Making microcapsules or microballoons by phase separation
    • B01J13/14—Polymerisation; cross-linking
    • B01J13/18—In situ polymerisation with all reactants being present in the same phase
    • B01J13/185—In situ polymerisation with all reactants being present in the same phase in an organic phase
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/20—After-treatment of capsule walls, e.g. hardening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/20—After-treatment of capsule walls, e.g. hardening
    • B01J13/203—Exchange of core-forming material by diffusion through the capsule wall
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F12/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F12/34—Monomers containing two or more unsaturated aliphatic radicals
    • C08F12/36—Divinylbenzene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/18—Suspension polymerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/34—Monomers containing two or more unsaturated aliphatic radicals
    • C08F212/36—Divinylbenzene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/32—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof from compositions containing microballoons, e.g. syntactic foams
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/10—Esters
    • C08F222/1006—Esters of polyhydric alcohols or polyhydric phenols
    • C08F222/104—Esters of polyhydric alcohols or polyhydric phenols of tetraalcohols, e.g. pentaerythritol tetra(meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2800/00—Copolymer characterised by the proportions of the comonomers expressed
    • C08F2800/20—Copolymer characterised by the proportions of the comonomers expressed as weight or mass percentages
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2810/00—Chemical modification of a polymer
    • C08F2810/20—Chemical modification of a polymer leading to a crosslinking, either explicitly or inherently

Definitions

  • the present disclosure relates to hollow particles.
  • Hollow particles are particles that have cavities inside the particles, and can scatter light well and have low light transmittance compared to solid particles whose insides are substantially filled with resin. Therefore, it is widely used as an organic pigment with excellent optical properties such as opacity and whiteness, and as a masking agent in water-based paints and paper coating compositions. In recent years, it has also been used as a lightening agent and a heat insulating agent for resins and paints used in various fields such as automobiles, electricity, electronics, and construction.
  • hollow particles may be included in the insulating resin layer for the purpose of suppressing the occurrence of crosstalk and an increase in transmission loss.
  • Crosstalk and transmission loss in an electronic circuit board can be suppressed by reducing the dielectric constant and dielectric loss tangent of the insulating resin layer. Since the inside of the hollow particles is hollow, attempts have been made to reduce the dielectric constant and the dielectric loss tangent of the insulating resin layer by adding the hollow particles.
  • Insulating resin layers used in electronic materials are also required to have adhesiveness, dimensional stability, and the like when used as lamination materials or bonding materials.
  • an insulating resin layer may be laminated on a metal plate such as a copper-clad laminate.
  • a metal plate such as a copper-clad laminate.
  • CTE coefficient of thermal expansion
  • the insulating resin layer is made to contain an inorganic filler such as silica.
  • Patent Literatures 1 and 2 describe a technique of adding hollow particles to a resin composition for use as an electronic material in order to achieve a low dielectric constant and a low dielectric loss tangent.
  • Patent Document 1 discloses hollow particles obtained by suspending a solution of a mixture of divinylbenzene, an initiator, and hexadecane in an aqueous solution of polyvinyl alcohol, followed by suspension polymerization. . Further, Patent Document 1 discloses that a copper-clad laminate using a resin composition containing hollow particles has a reduced coefficient of thermal expansion.
  • Patent Document 2 discloses hollow particles obtained by adding an oil component obtained by mixing an epoxy skeleton component and an organic solvent to an aqueous solution containing a curing agent and a water-soluble emulsifier, emulsifying the mixture, and performing interfacial polymerization.
  • the ratio of the average linear expansion coefficient ⁇ 2 at a temperature 10 to 50° C. higher than the glass transition temperature to the average linear expansion coefficient ⁇ 1 at a temperature 10 to 50° C. lower than the glass transition temperature is It is shown that when it is 3 or less, the occurrence of wrinkles and warpage near the glass transition temperature is suppressed.
  • An object of the present disclosure is to provide hollow particles with a reduced coefficient of thermal expansion.
  • the present inventor focused on the permeability of the shell of the hollow particles to a polar solvent, and adjusted the composition and formation method of the shell so that the hollow particles having a shell that is difficult for acetone to penetrate have a low coefficient of thermal expansion. I found
  • the present disclosure relates to hollow particles comprising a shell containing a resin and a hollow portion surrounded by the shell,
  • the porosity is 50% or more
  • the volume average particle diameter is 1.0 ⁇ m or more
  • the shell contains, as the resin, a polymer containing 70 to 100 parts by mass of crosslinkable monomer units in 100 parts by mass of all monomer units, a coefficient of thermal expansion at 80 to 200° C. of 10.0 ⁇ 10 ⁇ 5 /° C. or less;
  • Add 0.1 mg of hollow particles to 4 mL of acetone, shake for 10 minutes at a shaking speed of 100 rpm, and then leave to stand for 48 hours.
  • Hollow particles are provided in which the particles are less than 10% by weight.
  • the hollow particles of the present disclosure can have a thermal expansion coefficient of 6.0 ⁇ 10 ⁇ 5 /° C. or less at 25 to 80° C.
  • the hollow particles of the present disclosure can have a dielectric constant of 1.6 or less at a frequency of 1 GHz.
  • the dielectric loss tangent at a frequency of 1 GHz can be 0.010 or less.
  • the polymer contained in the shell contains, as the crosslinkable monomer unit, a bifunctional crosslinkable monomer unit derived from a bifunctional crosslinkable monomer,
  • the content of the bifunctional crosslinkable monomer unit may be 70 to 100 parts by mass in 100 parts by mass of the total monomer units of the polymer.
  • the polymer contained in the shell contains, as the crosslinkable monomer unit, a trifunctional or higher crosslinkable monomer unit derived from a trifunctional or higher crosslinkable monomer.
  • the content of the trifunctional or higher crosslinkable monomer unit may be 5 to 50 parts by mass based on 100 parts by mass of the total monomer units of the polymer.
  • the polymer contained in the shell is a hydrophilic non-crosslinking polymer derived from a hydrophilic non-crosslinking monomer having a solubility in distilled water at 20° C. of 0.3 g/L or more. further comprising a monomeric unit;
  • the content of the hydrophilic non-crosslinkable monomer unit is 2 to 15 parts by mass, and the content of the crosslinkable monomer unit is 70 to 98 parts by mass. It may be parts by mass.
  • the crosslinkable monomer unit contains a crosslinkable monomer derived from a (meth)acrylic crosslinkable monomer having a (meth)acryloyl group as a polymerizable functional group.
  • hollow particles with a reduced coefficient of thermal expansion can be provided.
  • FIG. 4 is a schematic diagram showing one embodiment of the suspension in the suspension step
  • a polymerizable monomer is a compound having a functional group capable of addition polymerization (in the present disclosure, sometimes simply referred to as a polymerizable functional group).
  • a compound having an ethylenically unsaturated bond as a functional group capable of addition polymerization is generally used as the polymerizable monomer.
  • Polymerizable monomers include non-crosslinkable monomers and crosslinkable monomers.
  • a non-crosslinkable monomer is a polymerizable monomer having only one polymerizable functional group, and a crosslinkable monomer has two or more polymerizable functional groups, and crosslinks are formed in the resin by a polymerization reaction. It is a polymerizable monomer to form.
  • a polymerizable monomer having a solubility in distilled water at 20°C of 0.3 g/L or more is referred to as a hydrophilic monomer, and a solubility in distilled water at 20°C is less than 0.3 g/L. is called a non-hydrophilic monomer.
  • the hollow particle of the present disclosure is a hollow particle comprising a shell containing a resin and a hollow portion surrounded by the shell,
  • the porosity is 50% or more
  • the volume average particle diameter is 1.0 ⁇ m or more
  • the shell contains, as the resin, a polymer containing 70 to 100 parts by mass of crosslinkable monomer units in 100 parts by mass of all monomer units, a coefficient of thermal expansion at 80 to 200° C. of 10.0 ⁇ 10 ⁇ 5 /° C. or less;
  • Add 0.1 mg of hollow particles to 4 mL of acetone, shake for 10 minutes at a shaking speed of 100 rpm, and then leave to stand for 48 hours. It is characterized in that the particles are less than 10% by weight.
  • the hollow particles of the present disclosure are particles comprising a resin-containing shell (outer shell) and a hollow portion surrounded by the shell.
  • the hollow portion is a hollow space clearly distinguished from the shell of the hollow particle formed by resin material.
  • the shell of the hollow particle may have a porous structure, in which case the hollow portion has a size that can be clearly distinguished from a large number of minute spaces uniformly distributed within the porous structure. have.
  • the hollow portion of the hollow particles can be confirmed, for example, by SEM observation of the cross section of the particles or by TEM observation of the particles as they are.
  • the hollow portion of the hollow particles is filled with air or a gas such as nitrogen, or is in a reduced pressure state close to vacuum.
  • the hollow particles have a hollow portion inside the particles, various compositions, molded articles, etc. to which the hollow particles are added can be imparted with properties such as weight reduction, heat insulation, and low dielectric constant. Since the hollow particles of the present disclosure are particles with a reduced coefficient of thermal expansion (CTE), the CTE can be further reduced in various compositions, molded articles, etc. to which the hollow particles of the present disclosure are added.
  • the polymer contained in the shell contains 70 to 100 parts by mass of crosslinkable monomer units in 100 parts by mass of the total monomer units, so the crosslinkable monomer occupying the shell The body unit content is high, and it is presumed that the covalent bond network is densely spread in the shell.
  • the hollow particles of the present disclosure have less than 10% by mass of hollow particles that precipitate in acetone in the immersion test, so that the shell has a dense structure that makes it difficult for acetone to permeate, and the hollow particles of the present disclosure are It is presumed that the crosslinked structure in the shell has become more dense.
  • the hollow particles of the present disclosure have a low CTE because the porosity is 50% or more, the proportion of hollow parts in the particles is sufficiently large, that is, the proportion of shells in the particles is sufficiently small, and the shells are dense. It is presumed that this is because, due to the structure, it has excellent heat resistance and is less susceptible to dimensional changes due to heat. Further, the hollow particles of the present disclosure are particles with reduced dielectric constant and dielectric loss tangent.
  • the hollow particles of the present disclosure have a porosity of 50% or more, a sufficiently large ratio of hollow portions in the particles, and furthermore, the shell has a dense structure, so that molecular motion is significantly restricted and dielectric relaxation is suppressed. It is presumed to exhibit excellent dielectric properties because it is unlikely to occur.
  • the hollow particles of the present disclosure are excellent in shell strength, deformation or crushing is unlikely to occur, and an increase in relative dielectric constant due to deformation or crushing of the hollow particles is suppressed, so that a low dielectric constant can be maintained. Conceivable.
  • Hollow particles of the present disclosure are particles with a reduced coefficient of thermal expansion (CTE).
  • the hollow particles of the present disclosure have a thermal expansion coefficient of 10.0 ⁇ 10 ⁇ 5 /° C. or less at 80 to 200° C., and can be 9.9 ⁇ 10 ⁇ 5 /° C. or less according to a preferred embodiment. It can be 9.8 ⁇ 10 ⁇ 5 /° C. or less.
  • the lower limit of the thermal expansion coefficient at 80 to 200° C. of the hollow particles of the present disclosure is not particularly limited, but is usually 5.0 ⁇ 10 ⁇ 5 /° C. or higher.
  • the coefficient of thermal expansion at 25 to 80° C. can be 6.0 ⁇ 10 ⁇ 5 /° C.
  • the thermal expansion coefficient ⁇ p of the hollow particles is the thermal expansion coefficient ⁇ c of the molded plate of the resin composition composed of the matrix resin and the hollow particles, the thermal expansion coefficient ⁇ r of the matrix resin alone, and the thermal expansion coefficient ⁇ r of the molded plate.
  • ⁇ p ( ⁇ c ⁇ SG r ⁇ r )/W p formula (E)
  • the thermal expansion coefficient is measured within a predetermined temperature range in accordance with JIS K7197:2012.
  • the matrix resin for example, an epoxy resin is used, and additives for curing the resin such as a curing agent and a curing catalyst may be included.
  • the hollow particles of the present disclosure are particles with reduced dielectric constant and dielectric loss tangent.
  • the dielectric constant at a frequency of 1 GHz can be 1.6 or less, and according to a more preferred embodiment, 1.5 or less.
  • the lower limit of the dielectric constant of the hollow particles of the present disclosure is not particularly limited, but is usually 1.0 or more.
  • the dielectric loss tangent at a frequency of 1 GHz can be 0.010 or less, and according to a more preferred embodiment, 0.009 or less.
  • the lower limit of the dielectric loss tangent of the hollow particles of the present disclosure is not particularly limited, it is usually 0.001 or more.
  • the dielectric constant and dielectric loss tangent of hollow particles are measured using a perturbation-type measuring device under the condition of a measurement frequency of 1 GHz.
  • the hollow particles of the present disclosure have a porosity of 50% or more, preferably 60% or more.
  • the porosity is equal to or higher than the above lower limit, the hollow particles have low CTE, relative permittivity and dielectric loss tangent, and are excellent in lightness, heat resistance and heat insulation.
  • the upper limit of the porosity of the hollow particles of the present disclosure is not particularly limited, it is preferably 90% or less, more preferably 85% or less, from the viewpoint of suppressing a decrease in the strength of the hollow particles and making them difficult to crush. , more preferably 80% or less.
  • the porosity of the hollow particles of the present disclosure is calculated from the apparent density D1 and the true density D0 of the hollow particles.
  • the method for measuring the apparent density D1 of hollow particles is as follows. First, a measuring flask with a volume of 100 cm 3 is filled with about 30 cm 3 of hollow particles, and the mass of the filled hollow particles is accurately weighed. The volumetric flask filled with hollow particles is then filled precisely to the marked line with isopropanol, taking care not to introduce air bubbles. Accurately weigh the mass of isopropanol added to the volumetric flask, and calculate the apparent density D 1 (g/cm 3 ) of the hollow particles based on the following formula (I).
  • Apparent density D 1 [mass of hollow particles]/(100-[mass of isopropanol]/[specific gravity of isopropanol at measurement temperature])
  • the apparent density D1 corresponds to the specific gravity of the entire hollow particle when the hollow portion is regarded as part of the hollow particle.
  • the method for measuring the true density D0 of the hollow particles is as follows. After pre-pulverizing the hollow particles, about 10 g of pulverized pieces of the hollow particles are filled into a volumetric flask having a capacity of 100 cm 3 , and the mass of the filled pulverized pieces is accurately weighed. After that, isopropanol is added to the volumetric flask in the same manner as the above apparent density measurement, the mass of isopropanol is accurately weighed, and the true density D 0 (g/cm 3 ) of the hollow particles is calculated based on the following formula (II). do.
  • True density D 0 [mass of pulverized pieces of hollow particles]/(100-[mass of isopropanol]/[specific gravity of isopropanol at measurement temperature])
  • the true density D0 corresponds to the specific gravity of only the shell portion of the hollow particles. As is clear from the above measurement method, the hollow portion is not considered part of the hollow particle when calculating the true density D0 .
  • the porosity (%) of the hollow particles is calculated by the following formula (III) from the apparent density D1 and the true density D0 of the hollow particles.
  • Formula (III) Porosity (%) 100 - (apparent density D 1 / true density D 0 ) x 100
  • the hollow particles of the present disclosure have a volume average particle size of 1.0 ⁇ m or more.
  • the volume average particle diameter of the hollow particles is at least the above lower limit, the cohesiveness of the hollow particles becomes small, so that excellent dispersibility can be exhibited, and the insulating resin layer of the electronic circuit board can be incorporated. It is suitable for use as a material for electronic circuit boards because it does not easily cause wiring defects.
  • the lower limit of the volume average particle diameter of the hollow particles of the present disclosure is preferably 3.0 ⁇ m or more, more preferably 5.0 ⁇ m or more, and even more preferably 7.0 ⁇ m or more.
  • the upper limit of the volume average particle diameter of the hollow particles of the present disclosure is not particularly limited, but the strength of the hollow particles is improved, the thickness of the shell tends to be uniform, and it is easy to use as a material for electronic circuit boards. Therefore, it is preferably 30.0 ⁇ m or less, more preferably 20.0 ⁇ m or less, and still more preferably 15.0 ⁇ m or less.
  • the particle size distribution (volume average particle size (Dv)/number average particle size (Dn)) of the hollow particles may be, for example, 1.1 or more and 2.5 or less. When the particle size distribution is 2.5 or less, particles with little variation in compressive strength characteristics and heat resistance among particles can be obtained. Moreover, when the particle size distribution is 2.5 or less, for example, when manufacturing a sheet-like compact, a product having a uniform thickness can be manufactured.
  • the volume average particle diameter (Dv) and number average particle diameter (Dn) of the hollow particles are obtained, for example, by measuring the particle diameter of the hollow particles with a laser diffraction particle size distribution analyzer, and calculating the number average and volume average, respectively. The values obtained can be taken as the number average particle size (Dn) and volume average particle size (Dv) of the particles.
  • the particle size distribution is obtained by dividing the volume average particle size by the number average particle size.
  • the lower limit of the thickness of the shell of the hollow particles of the present disclosure is preferably 0.1 ⁇ m or more, more preferably 0.3 ⁇ m or more, and still more preferably 0.5 ⁇ m or more from the viewpoint of improving the strength of the hollow particles
  • the upper limit is preferably 6 ⁇ m or less, more preferably 4 ⁇ m or less, even more preferably 2 ⁇ m or less, and even more preferably 1 ⁇ m or less, from the viewpoint of increasing the porosity.
  • the thickness of the shell of the hollow particles is at least the above lower limit, the strength of the shell is improved.
  • the shell has a dense structure that makes it difficult for acetone to permeate.
  • the thickness of the shell of the hollow particles is obtained by calculating the inner diameter r of the hollow particles by the following formula (1) using the volume average particle diameter R and the porosity of the hollow particles, and using the inner diameter r and the volume average particle diameter R can be calculated by the following formula (2).
  • Shell thickness (Rr)/2 Formula (2)
  • the difference between the shell thickness calculated in this way and the average thickness of the shell at 20 points actually measured is usually within ⁇ 10% of these average values.
  • the calculated shell thickness can be regarded as the shell thickness of the hollow particles.
  • the thickness at each point of the shell of the hollow particle used to obtain the average value of the thickness of the shell at 20 points can be measured, for example, by observing a fragment of the shell obtained by splitting the hollow particle with an SEM. can be done.
  • the shape of the hollow particles of the present disclosure is not particularly limited as long as a hollow portion is formed inside, and examples thereof include spherical, ellipsoidal, irregular shapes, and the like. Among these, a spherical shape is preferable because of ease of production.
  • Hollow particles may have one or more hollows.
  • the shell of the hollow particle and, in the case of having two or more hollow portions, partition walls separating adjacent hollow portions may be porous.
  • the inside of the particles preferably has only one hollow portion.
  • the hollow particles may have an average circularity of 0.950 to 0.995.
  • An example of the image of the shape of the hollow particles is a bag made of a thin film and inflated with gas, the cross-sectional view of which is the hollow particle 100 in (5) of FIG. 1 described later.
  • a thin film is provided on the outside and the inside is filled with gas.
  • the particle shape can be confirmed by, for example, SEM or TEM. Further, the shape of the inside of the particle can be confirmed by SEM or TEM after slicing the particle by a known method.
  • the hollow particles of the present disclosure contain, as the resin in the shell, a polymer containing 70 to 100 parts by mass of crosslinkable monomer units in 100 parts by mass of all monomer units.
  • the polymer forms the skeleton of the shell of the hollow particle, and by including the crosslinkable monomer units in the above ratio, the shell of the hollow particle of the present disclosure has a dense covalent bond network. It becomes what was done.
  • the content of the crosslinkable monomer unit in 100 parts by mass of the total monomer units reduces the CTE, dielectric constant and dielectric loss tangent of the hollow particles, and improves the strength of the hollow particles.
  • the amount is preferably 98 parts by mass or less, more preferably 97 parts by mass or less.
  • the crosslinkable monomer unit is a monomer unit derived from a crosslinkable monomer, and the content of the crosslinkable monomer unit in the polymer is less than 100 parts by mass.
  • the monomer units other than the crosslinkable monomer units are non-crosslinkable monomer units derived from non-crosslinkable monomers.
  • the polymer is typically a first polymerizable monomer and a second polymerizable monomer obtained by a first polymerization reaction and a second polymerization reaction in the method for producing hollow particles of the present disclosure, which will be described later.
  • the crosslinkable monomer unit and the non-crosslinkable monomer unit contained in the polymer are usually the first polymerizable monomer and the second polymerizable monomer described later. It is derived from the polymer.
  • the specific contents of the crosslinkable monomer and the non-crosslinkable monomer used for synthesizing the polymer are as described later in the method for producing hollow particles of the present disclosure.
  • the polymer includes, as crosslinkable monomer units, bifunctional crosslinkable monomer units derived from a bifunctional crosslinkable monomer, and trifunctional or higher functional units derived from a trifunctional or higher crosslinkable monomer.
  • a crosslinkable monomer unit derived from a bifunctional crosslinkable monomer may be referred to as a "bifunctional crosslinkable monomer unit", and a trifunctional or higher crosslinkable monomer
  • a crosslinkable monomeric unit derived from a polymer may be referred to as a "trifunctional or higher crosslinkable monomeric unit”.
  • the content of the bifunctional crosslinkable monomer unit in 100 parts by mass of the total monomer units of the polymer is not particularly limited.
  • the lower limit is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, from the viewpoint of lowering the CTE and improving the strength of the hollow particles.
  • the upper limit may be 100 parts by mass or less, but from the viewpoint of sufficiently containing a trifunctional or higher crosslinkable monomer unit or a hydrophilic non-crosslinkable monomer unit described later, it is preferably 98 parts by mass. It is not more than 95 parts by mass, more preferably not more than 90 parts by mass.
  • the content of the trifunctional or higher crosslinkable monomer unit in 100 parts by mass of the total monomer units of the polymer is not particularly limited.
  • the lower limit is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more, from the viewpoint of lowering the CTE and improving the strength of the hollow particles.
  • the upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and sufficiently contains bifunctional or higher crosslinkable monomer units or hydrophilic non-crosslinkable monomer units described later. From the point of view of increasing
  • the crosslinkable monomer unit contained in the polymer contains a crosslinkable monomer unit derived from a (meth)acrylic crosslinkable monomer having a (meth)acryloyl group as a polymerizable functional group. good too.
  • the hollow particles of the present disclosure are excellent in strength and heat resistance, and furthermore, the adhesiveness of the resin composition to which the hollow particles of the present disclosure are added can be improved.
  • the content of the crosslinkable monomer unit derived from the (meth)acrylic crosslinkable monomer is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and still more preferably 90 parts by mass or more in 100 parts by mass of the crosslinkable monomer unit, and the crosslinkable monomer unit is (meth)acrylic crosslinked may be composed of a single monomeric unit.
  • the specific content of the (meth)acrylic crosslinkable monomer is as described later in the method for producing hollow particles of the present disclosure.
  • the polymer preferably further contains a non-crosslinking monomer unit, and may contain a hydrophilic non-crosslinking monomer unit having a solubility of 0.3 g/L or more in distilled water at 20°C. More preferably, it preferably contains a hydrophilic non-crosslinking monomer unit derived from the second polymerizable monomer described later.
  • the polymer contains a combination of crosslinkable monomer units and non-crosslinkable monomer units, the mechanical properties of the shell of the hollow particles are improved. By containing non-crosslinkable monomer units, the shell tends to have a dense structure, so the CTE, dielectric constant and dielectric loss tangent of the hollow particles tend to decrease, and the strength of the hollow particles tends to improve.
  • the content of the non-crosslinkable monomer units in 100 parts by mass of the total monomer units is 0 to 30 parts by mass, and from the viewpoint of improving the strength of the hollow particles, it is preferably 2 to 25 parts. parts by mass, more preferably 4 to 15 parts by mass.
  • the content of the hydrophilic non-crosslinking monomer units in 100 parts by mass of the total monomer units improves the strength of the hollow particles, and the CTE, dielectric constant and dielectric of the hollow particles From the viewpoint of reducing the tangent, it is preferably 2 to 15 parts by mass, more preferably 3 to 13 parts by mass, and even more preferably 4 to 10 parts by mass.
  • the content of the polymer is preferably 90% by mass or more, more preferably 95% by mass or more, based on 100% by mass of the total solid content of the shell.
  • the shell provided by the hollow particles of the present disclosure may further contain polar components.
  • polar components include organic acids or metal salts thereof, and polar resins.
  • the specific content of the polar component is as described later in the method for producing hollow particles of the present disclosure.
  • the inclusion of a polar component in the shell of the hollow particles and its content can be confirmed by, for example, pyrolysis gas chromatography.
  • the total content of the organic acid or its metal salt in the shell is preferably 0.0001 to 0.1% by mass. and more preferably 0.001 to 0.01% by mass.
  • the content of the polar resin in the shell is preferably 0.1 to 10.0 mass%, more preferably 0. .3 to 8.0% by mass.
  • the hollow particles of the present disclosure are obtained by adding 0.1 mg of the hollow particles to 4 mL of acetone in an environment of 25 ° C., shaking for 10 minutes at a shaking speed of 100 rpm, and then standing for 48 hours. , less than 10% by weight of hollow particles precipitate in acetone.
  • the proportion of hollow particles that precipitate in acetone in the immersion test is an index of the denseness of the shell of the hollow particles. is estimated to be In addition, it is presumed that the denser the shell of the hollow particles, the lower the CTE, dielectric constant and dielectric loss tangent of the hollow particles.
  • the proportion of hollow particles that precipitate in acetone in the immersion test may be less than 10% by mass, and more preferably less than 5% by mass.
  • hollow particles having a porosity of 50% or more in order to make the amount of hollow particles that precipitate in acetone in the immersion test less than 10% by mass, for example, as in the method for producing hollow particles of the present disclosure, which will be described later, there is a problem.
  • the step of subjecting the turbid liquid to a polymerization reaction when the polymerization conversion of the first polymerizable monomer containing a specific amount or more of the crosslinkable monomer is 93% by mass or more, it is a hydrophilic monomer.
  • the hollow Particles may be produced.
  • hollow particles of the present disclosure preferably have 5 or less hollow particles out of 100 hollow particles that have continuous pores or shell defects in SEM observation.
  • hollow particles include those in which the shell does not have a communicating hole through which the hollow portion and the outer space of the particle communicate, and those in which the shell has one or two or more communicating holes, and the hollow portion communicates with the outside of the particle through the communicating hole.
  • the diameter of the communicating pores is usually about 10 to 500 nm.
  • the communicating pores may impart beneficial functions to the hollow particles, they also reduce the strength of the hollow particles and make them susceptible to crushing because they are portions where the shell is missing. Hollow particles may also have crack-like shell defects that are extremely large relative to the size of the particles.
  • a crack having a length of 1 ⁇ m or more generally significantly deteriorates the strength of the hollow particle and is recognized as a shell defect.
  • the number of hollow particles having continuous pores or shell defects out of 100 hollow particles is considered to be 5 or less. be able to.
  • the amount of precipitated hollow particles may be 10% by mass or more in the hollow particle immersion test described above. Therefore, in the hollow particle immersion test described above, when the amount of precipitated hollow particles is less than 10% by mass, it means that the shell has extremely few communicating pores and shell defects, and the shell has a dense crosslinked structure. Conceivable.
  • the hollow particles of the present disclosure are produced by, for example, A step of preparing a mixture containing a first polymerizable monomer containing a crosslinkable monomer, a hydrocarbon solvent, a dispersion stabilizer, and an aqueous medium; A step of preparing a suspension in which droplets of a monomer composition containing the first polymerizable monomer and the hydrocarbon solvent are dispersed in the aqueous medium by suspending the mixed liquid.
  • the solubility in distilled water at 20°C is 0.3 g/L or more. It can be obtained by a method for producing hollow particles in which a second polymerizable monomer is added and further subjected to a polymerization reaction.
  • a mixed liquid containing the first polymerizable monomer, a hydrocarbon solvent, a dispersion stabilizer, and an aqueous medium is suspended to obtain the first polymerizable monomer and carbonization.
  • Suspension in which droplets having a distribution structure in which the hydrogen-based solvent undergoes phase separation, the first polymerizable monomer is unevenly distributed on the surface side, and the hydrocarbon-based solvent is unevenly distributed in the center are dispersed in the aqueous medium. It follows the basic technique of preparing a liquid and subjecting this suspension to a polymerization reaction to harden the surface of the droplets to form hollow particles having a hollow space filled with a hydrocarbon solvent.
  • the more polymerizable functional groups that remain unreacted the coarser the crosslinked structure of the shell.
  • the hollow particle immersion test it is believed that 10% by mass or more of the hollow particles are precipitated in acetone.
  • a suspension in which droplets of a monomer composition containing a first polymerizable monomer rich in a crosslinkable monomer are dispersed in an aqueous medium is subjected to a polymerization reaction.
  • the second polymerizable monomer which is a hydrophilic monomer, is added.
  • the reaction rate of the entire polymerizable monomers including the first polymerizable monomer and the second polymerizable monomer can be improved.
  • particles having a shell containing a polymer of the first polymerizable monomer and a hollow portion filled with a hydrocarbon-based solvent obtained by the first polymerization reaction are referred to as the first and the composition containing the first precursor particles is sometimes referred to as the first precursor composition.
  • Particles having a shell containing a polymer of the first polymerizable monomer and the second polymerizable monomer obtained by the second polymerization reaction and a hollow portion filled with a hydrocarbon-based solvent is sometimes referred to as a second precursor particle, considering it as an intermediate of hollow particles in which the hollow portion is filled with gas, and the composition containing the second precursor particles is referred to as the second precursor composition sometimes referred to as the second precursor composition sometimes referred to as
  • the solubility of the second polymerizable monomer in distilled water at 20° C. is equal to or higher than the above specific value. It tends to be entrapped within the shell of one precursor particle.
  • the second polymerizable monomer which is a hydrophilic monomer, has affinity with both the first polymerizable monomer and the aqueous medium, so when added to the first precursor composition, , is incorporated into the shell formed by the first polymerizable monomer and is believed to promote thermal motion of the shell.
  • the second polymerizable monomer is incorporated into the shell formed by the first polymerizable monomer, and the polymerization reaction proceeds while the thermal movement of the shell is promoted. progresses, the reaction rate is high, and the polymerization reaction of the second polymerizable monomer incorporated in the shell and the polymerizable functional groups of the first polymerizable monomer remaining unreacted is sufficient.
  • the crosslinked structure becomes denser, so it is presumed that a shell is formed that makes it difficult for acetone to permeate.
  • the method for producing hollow particles includes a step of preparing a mixed solution, a step of preparing a suspension, and a step of subjecting the suspension to a polymerization reaction, and may further include steps other than these. Moreover, as long as it is technically possible, two or more of the above steps and other additional steps may be performed simultaneously as one step, or their order may be changed. For example, the preparation and suspension of the mixed solution may be performed simultaneously in one step, such as adding the materials for preparing the mixed solution while simultaneously suspending the mixture.
  • a preferable example of the method for producing the hollow particles is a production method including the following steps.
  • Polymerization step (3-1) Second One polymerization step By performing a first polymerization reaction of subjecting the suspension to a polymerization reaction until the polymerization conversion rate of the first polymerizable monomer reaches 93% by mass or more, the first polymerizable monomer Step of preparing a first precursor composition containing first precursor particles having a shell containing a monomeric polymer and a hollow portion filled with a hydrocarbon solvent
  • Second Polymerization step By adding a second polymerizable monomer having a solubility of 0.3 g/L or more in distilled water at 20°C to the first precursor composition and performing a second polymerization reaction, A second precursor comprising second precursor particles
  • Step of preparing a composition (4) Solid-liquid separation step A step of solid-liquid separation of the second precursor composition to obtain second precursor particles containing a hydrocarbon-based solvent in their hollow portions, and (5) Solvent removal step A step of removing the hydrocarbon-based solvent contained in the second precursor particles obtained in the solid-liquid separation step to obtain hollow particles
  • FIG. 1 is a schematic diagram showing an example of the above manufacturing method.
  • (1) to (5) in FIG. 1 correspond to the above steps (1) to (5).
  • White arrows between each figure indicate the order of each step.
  • FIG. 1 is only a schematic diagram for explanation, and the manufacturing method is not limited to the one shown in the diagram.
  • the structures, dimensions and shapes of the materials used in the manufacturing methods of the present disclosure are not limited to the structures, dimensions and shapes of the various materials in these figures.
  • (1) of FIG. 1 is a cross-sectional schematic diagram showing one embodiment of the liquid mixture in the liquid mixture preparation step. As shown in this figure, the mixture contains an aqueous medium 1 and a low-polarity material 2 dispersed in the aqueous medium 1 .
  • the low-polarity material 2 means a material that has low polarity and is difficult to mix with the aqueous medium 1 .
  • the low polar material 2 contains a first polymerizable monomer and a hydrocarbon solvent.
  • (2) of FIG. 1 is a cross-sectional schematic diagram showing one embodiment of the suspension in the suspension step.
  • the suspension comprises an aqueous medium 1 and droplets 10 of a monomer composition dispersed in the aqueous medium 1 .
  • the droplet 10 of the monomer composition contains the first polymerizable monomer and the hydrocarbon-based solvent, but the distribution within the droplet is not uniform.
  • the hydrocarbon-based solvent 4a and the material 4b other than the hydrocarbon-based solvent containing the first polymerizable monomer are phase-separated, and the hydrocarbon-based solvent 4a is in the center. It has a structure in which it is unevenly distributed, the material 4b other than the hydrocarbon solvent is unevenly distributed on the surface side, and a dispersion stabilizer (not shown) adheres to the surface.
  • (3) of FIG. 1 shows one implementation of a composition (second precursor composition) containing hollow particles (second precursor particles) containing a hydrocarbon-based solvent in the hollow portion obtained by the polymerization step. It is a cross-sectional schematic diagram which shows a form.
  • the composition includes an aqueous medium 1 and hollow particles (second precursor particles) 20 dispersed in the aqueous medium 1 and containing a hydrocarbon solvent 4a in their hollow portions.
  • the shell 6 forming the outer surface of the second precursor particle 20 is formed by the polymerization of the first polymerizable monomer in the droplet 10 of the monomer composition and the second polymer that is added later. It is formed by polymerization of polymerizable monomers.
  • FIG. 1(4) is a schematic cross-sectional view showing an embodiment of hollow particles (second precursor particles) containing a hydrocarbon-based solvent in the hollow portion after the solid-liquid separation step. (4) of FIG. 1 shows a state where the aqueous medium 1 is removed from the state of (3) of FIG. (5) of FIG.
  • FIG. 1 is a schematic cross-sectional view showing one embodiment of the hollow particles after the solvent removal step.
  • (5) of FIG. 1 shows a state in which the hydrocarbon-based solvent 4a is removed from the state of (4) of FIG.
  • the hydrocarbon-based solvent 4a is removed from the state of (4) of FIG.
  • Liquid mixture preparation step This step is a step of preparing a liquid mixture containing a first polymerizable monomer, a hydrocarbon solvent, a dispersion stabilizer, and an aqueous medium.
  • the mixed liquid may further contain a polar component.
  • the mixed liquid preferably contains an oil-soluble polymerization initiator as a polymerization initiator.
  • the mixed solution may further contain other materials such as a suspension stabilizer as long as the effects of the present disclosure are not impaired.
  • A first polymerizable monomer, (B) polar component, (C) oil-soluble polymerization initiator, (D) hydrocarbon solvent, (E) dispersion stabilizer, (F ) will be explained in the order of the aqueous medium.
  • the first polymerizable monomer contains at least a crosslinkable monomer, and further contains a non-crosslinkable monomer within a range that does not impair the effects of the present disclosure. good too.
  • a (meth)acrylic polymer having a (meth)acryloyl group as a polymerizable functional group is used because the polymerization reaction is easy to stabilize and hollow particles with high heat resistance can be obtained. can be preferably used.
  • a hydrocarbon monomer composed of carbon and hydrogen can also be preferably used.
  • Crosslinkable monomer Since the crosslinkable monomer has a plurality of polymerizable functional groups, the monomers can be linked together, and the crosslink density of the shell can be increased.
  • crosslinkable monomers include divinylbenzene, divinyldiphenyl, divinylnaphthalene, diallyl phthalate, diallylamine, allyl (meth) acrylate, vinyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate.
  • examples of hydrophilic crosslinkable monomers having a solubility in distilled water at 20° C. of 0.3 g/L or more include ethylene glycol dimethacrylate, diethylene glycol diacrylate, and allyl methacrylate. , vinyl methacrylate, 2-hydroxy-3-methacrylpropyl acrylate, diallylamine and the like.
  • the crosslinkable monomer contained in the first polymerizable monomer may be a hydrophilic crosslinkable monomer having a solubility in distilled water at 20° C. of 0.3 g/L or more, or 0.3 g/L or more. It may be less than 3 g/L of non-hydrophilic crosslinkable monomer, and is not particularly limited.
  • the first polymerizable monomer contains, as a crosslinkable monomer, at least one selected from bifunctional crosslinkable monomers and trifunctional or higher crosslinkable monomers.
  • a crosslinkable monomer from the viewpoint of lowering the CTE of the hollow particles, it is preferable to contain at least a bifunctional crosslinkable monomer, and from the viewpoint of further improving the strength of the hollow particles, a bifunctional crosslinkable monomer and a trifunctional or higher functional
  • the first polymerizable monomer contains a trifunctional or higher crosslinkable monomer, it is excellent in that the covalent bond network can be more densely spread in the shell, but the first polymerization There is a tendency that unreacted polymerizable functional groups tend to remain after the reaction.
  • the first polymerizable monomer contains a trifunctional or higher crosslinkable monomer
  • a hydrophilic monomer is added as the second polymerizable monomer to form the second polymerizable monomer.
  • the polymerization reaction is easy to stabilize, and hollow particles having excellent strength and heat resistance can be obtained, and the obtained hollow particles are included.
  • a (meth)acrylic crosslinkable monomer having a (meth)acryloyl group as a polymerizable functional group is preferred from the viewpoint that the adhesiveness of the resin composition to be used is improved.
  • the bifunctional crosslinkable monomer used for the first polymerizable monomer includes allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol di(meth) )
  • Bifunctional (meth)acrylic crosslinkable monomers such as acrylates are preferable, and among them, ethylene glycol di(meth)acrylate and pentaerythritol di(meth)acrylate are more preferable.
  • the (meth)acrylic crosslinkable monomer may be a crosslinkable monomer having at least one (meth)acryloyl group as a polymerizable functional group, but all polymerizable functional groups is preferably a (meth)acryloyl group.
  • the content of the (meth)acrylic crosslinkable monomer is the crosslinkability contained in the first polymerizable monomer.
  • the crosslinkable monomer contained in the first polymerizable monomer is , (meth)acrylic crosslinkable monomers.
  • the crosslinkable monomer contained in the first polymerizable monomer includes hydrocarbon-based crosslinked monomers such as divinylbenzene, divinylbiphenyl, and divinylnaphthalene. divinylbenzene is more preferred among these.
  • the content of the crosslinkable monomer is preferably 75 to 100 parts by mass, more preferably 80 to 100 parts by mass, still more preferably 85 to 100 parts by mass, and more More preferably 90 to 100 parts by mass.
  • the polymer contained in the formed shell contains 70 to 100 mass parts of the crosslinkable monomer unit in 100 mass parts of the total monomer units. It tends to be a polymer containing moieties.
  • the content of the crosslinkable monomer units in the shell of the hollow particles is sufficiently large, the covalent bond network is densely spread in the shell, resulting in the CTE, relative permittivity and dielectric loss tangent of the hollow particles. can be reduced and the strength of the hollow particles can be improved.
  • the content of the bifunctional crosslinkable monomer in 100 parts by mass of the first polymerizable monomer is not particularly limited, but the lower limit is 70 parts by mass or more, more preferably 75 parts by mass, from the viewpoint of reducing the CTE, dielectric constant and dielectric loss tangent of the hollow particles and improving the strength of the hollow particles.
  • the upper limit may be 100 parts by mass or less, preferably 95 parts by mass or less, more preferably 95 parts by mass or less, from the viewpoint of sufficiently containing trifunctional or higher crosslinkable monomer units. is 90 parts by mass or less.
  • the trifunctional or higher crosslinkable monomer in 100 parts by mass of the first polymerizable monomer
  • the content of is not particularly limited, but the lower limit is preferably 5 parts by mass or more from the viewpoint of reducing the CTE, dielectric constant and dielectric loss tangent of the hollow particles and improving the strength of the hollow particles. It is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and the upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. From the point of content, it is more preferably 30 parts by mass or less, and still more preferably 25 parts by mass or less.
  • the first polymerizable monomer may further contain a non-crosslinkable monomer.
  • a monovinyl monomer is preferably used as the non-crosslinkable monomer.
  • a monovinyl monomer is a compound having one polymerizable vinyl functional group.
  • Monovinyl monomers include, for example, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and (meth)acrylic acid alkyl esters having an alkyl group of 6 or more carbon atoms; styrene, vinyltoluene, ⁇ -methyl Aromatic vinyl monomers such as styrene, p-methylstyrene and halogenated styrene; Monoolefin monomers such as ethylene, propylene and butylene; Diene monomers such as butadiene and isoprene; Vinyl carboxylates such as vinyl acetate ester monomers; vinyl halide monomers such as vinyl chloride; vinylidene halide monomers such as vinylidene chloride; vinylpyridine monomers; ) Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate having an alkyl group of 1 to 5 carbon atoms (meth
  • polar group-containing non-crosslinking monomer for example, a non-crosslinking monomer containing a polar group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group, an amino group, a polyoxyethylene group and an epoxy group is preferably exemplified. be able to.
  • carboxyl group-containing monomers such as ethylenically unsaturated carboxylic acid monomers such as (meth)acrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid and butentricarboxylic acid ; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxyl group-containing monomers such as 4-hydroxybutyl (meth) acrylate; sulfonic acid group-containing monomers such as styrenesulfonic acid; dimethyl amino group-containing monomers such as aminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; polyoxyethylene group-containing monomers such as methoxypolyethylene glycol (meth) acrylate; glycidyl (meth) acrylate, allyl glycidyl ether,
  • Examples include epoxy group-containing monomers such as
  • non-crosslinking monomers can be used alone or in combination of two or more.
  • a hydrophilic non-crosslinkable monomer is preferable, and an alkyl group having 1 to 5 carbon atoms (Meth)acrylic acid alkyl esters having is more preferred, (meth)acrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms are more preferred, and methyl (meth)acrylate is even more preferred.
  • polymerizable monomers other than crosslinkable monomers are non-crosslinkable monomers.
  • the content of the non-crosslinkable monomer in the first polymerizable monomer is preferably 0 to 25 parts by mass in 100 parts by mass of the first polymerizable monomer, and the first polymerizable monomer From the viewpoint of suppressing the decrease in reactivity of the polymer, reducing the CTE, dielectric constant and dielectric loss tangent of the hollow particles, and improving the strength of the hollow particles, non-crosslinking in the first polymerizable monomer
  • the content of the polymerizable monomer is more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less, and the first polymerizable monomer is a non-crosslinkable monomer It is particularly preferred that it contains no body.
  • the content of the first polymerizable monomer in the mixed liquid is not particularly limited, but from the viewpoint of the balance between the porosity of the hollow particles, the particle diameter and the mechanical strength, the amount of the components in the mixed liquid excluding the aqueous medium It is usually 15 to 55% by mass, more preferably 25 to 40% by mass, based on 100% by mass of the total mass.
  • the amount of the first polymerizable monomer relative to the total mass of 100 mass% of the solid content excluding the hydrocarbon solvent among the materials that become the oil phase in the mixed liquid is preferably 90% by mass or more, more preferably 95% by mass or more.
  • the mixture may further contain a polar component.
  • a polar component By including a polar component in the mixed liquid, it is possible to obtain hollow particles that are less likely to be crushed even if the porosity is high.
  • the polar component an organic acid or a metal salt thereof, or a polar resin to be described later can be used.
  • organic acids include rosin acid and higher fatty acids.
  • Higher fatty acids include, for example, higher fatty acids having 10 to 25 carbon atoms that do not contain carbon atoms in the carboxyl group.
  • metals used in metal salts of organic acids include alkali metals such as Li, Na and K, and alkaline earth metals such as Mg and Ca. and K are more preferred.
  • the total content of the organic acid or its metal salt is preferably 0 with respect to a total of 100 parts by mass of the first polymerizable monomer and the hydrocarbon solvent. 0.0001 parts by mass or more and 0.1 parts by mass or less, more preferably 0.001 parts by mass or more and 0.01 parts by mass or less, and still more preferably 0.0015 parts by mass or more and 0.006 parts by mass or less .
  • the content is at least the lower limit, the shell thickness of the hollow particles can be easily controlled, and the strength of the hollow particles can be improved.
  • the content is equal to or less than the upper limit, it is possible to suppress a decrease in the content of the polymerizable monomer, thereby suppressing a decrease in shell strength and further suppressing crushing of the hollow particles. .
  • a polar resin refers to a polymer containing repeating units containing heteroatoms. Specific examples include acrylic resins, polyester resins, vinyl resins containing heteroatoms, and the like.
  • the polar resin may be a homopolymer or copolymer of a heteroatom-containing monomer, or a copolymer of a heteroatom-containing monomer and a heteroatom-free monomer. .
  • the polar resin is a copolymer of a heteroatom-containing monomer and a heteroatom-free monomer, all repeating units constituting the copolymer are easy to control the particle size of the hollow particles.
  • the proportion of heteroatom-containing monomer units is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more.
  • the number average molecular weight (Mn) of the polar resin is not particularly limited, but is preferably in the range of 3000 to 20000 in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran. , more preferably in the range of 4000 or more and 17000 or less, and still more preferably in the range of 6000 or more and 15000 or less.
  • GPC gel permeation chromatography
  • the content of the polar resin is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 100 parts by mass of the first polymerizable monomer. It is 0.3 parts by mass or more and 8.0 parts by mass or less, more preferably 0.5 parts by mass or more and 8.0 parts by mass or less.
  • the content is at least the lower limit, the shell thickness of the hollow particles can be easily controlled, and the strength of the hollow particles can be improved.
  • the content is equal to or less than the upper limit, it is possible to suppress a decrease in the content of the polymerizable monomer, thereby suppressing a decrease in shell strength and further suppressing crushing of the hollow particles. .
  • the mixture preferably contains an oil-soluble polymerization initiator as the polymerization initiator.
  • an emulsion polymerization method using a water-soluble polymerization initiator and a suspension polymerization method using an oil-soluble polymerization initiator.
  • Suspension polymerization can be carried out by using an agent.
  • the oil-soluble polymerization initiator is not particularly limited as long as it is lipophilic and has a solubility in water of 0.2% by mass or less.
  • oil-soluble polymerization initiators examples include benzoyl peroxide, lauroyl peroxide, t-butyl peroxide-2-ethylhexanoate, 2,2'-azobis(2,4-dimethylvaleronitrile), azobisisobutyronitrile. etc.
  • the content of the oil-soluble polymerization initiator is preferably 0.1 to 10 parts by mass, more preferably It is 0.5 to 7 parts by mass, more preferably 1 to 5 parts by mass.
  • the content of the oil-soluble polymerization initiator is 0.1 to 10 parts by mass, the polymerization reaction is sufficiently advanced, and the possibility that the oil-soluble polymerization initiator remains after the completion of the polymerization reaction is small, and unexpected side reactions do not occur. is likely to progress.
  • a hydrocarbon solvent is used as the non-polymerizable and sparingly water-soluble organic solvent.
  • the hydrocarbon-based solvent functions as a spacer material that forms a hollow inside the particles.
  • a suspension is obtained in which droplets of the monomer composition containing the hydrocarbon solvent are dispersed in the aqueous medium.
  • the hydrocarbon-based solvent with low polarity tends to gather inside the droplets of the monomer composition.
  • the hydrocarbon-based solvent is distributed in the droplets, and the materials other than the hydrocarbon-based solvent are distributed around the periphery according to their respective polarities. Then, in the polymerization step to be described later, an aqueous dispersion containing hollow particles encapsulating the hydrocarbon-based solvent is obtained. That is, the hydrocarbon-based solvent gathers inside the particles, so that a hollow portion filled with the hydrocarbon-based solvent is formed inside the obtained precursor particles.
  • hydrocarbon solvent is not particularly limited.
  • hydrocarbon solvents include saturated hydrocarbon solvents such as butane, pentane, normal hexane, cyclohexane, heptane and octane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; carbon disulfide and carbon tetrachloride; A solvent having relatively high volatility such as The porosity of the hollow particles can be adjusted by changing the amount of the hydrocarbon-based solvent in the mixed liquid. In the suspension step described later, the polymerization reaction proceeds in a state in which the oil droplets containing the crosslinkable monomer and the like enclose the hydrocarbon solvent. Porosity tends to be high.
  • the hydrocarbon solvent preferably has a saturated hydrocarbon solvent content of 50% by mass or more in 100% by mass of the total amount of the hydrocarbon solvent.
  • the ratio of the saturated hydrocarbon-based solvent is preferably 60% by mass or more, more preferably 80% by mass, in order to further suppress the generation of porous particles and to easily make the hollow part of each hollow particle uniform. % by mass or more.
  • the hydrocarbon-based solvent a hydrocarbon-based solvent having 4 to 7 carbon atoms is preferable.
  • a hydrocarbon compound having 4 to 7 carbon atoms is easily included in the first precursor particles during the polymerization step, and can be easily removed from the second precursor particles during the solvent removal step.
  • hydrocarbon solvents having 5 or 6 carbon atoms are particularly preferred.
  • the hydrocarbon-based solvent preferably has a boiling point of 130° C. or lower, more preferably 100° C. or lower, because it is easily removed in the solvent removal step described below.
  • the hydrocarbon-based solvent preferably has a boiling point of 50° C. or higher, more preferably 60° C. or higher, because it is easily included in the first precursor particles.
  • the hydrocarbon-based solvent preferably has a dielectric constant of 3 or less at 20°C.
  • the relative dielectric constant is one of the indices that indicate the degree of polarity of a compound.
  • the dielectric constant of the hydrocarbon-based solvent is sufficiently low as 3 or less, phase separation proceeds rapidly in droplets of the monomer composition, and hollows are likely to be formed.
  • solvents having a dielectric constant of 3 or less at 20° C. are as follows. The value in parenthesis is the relative permittivity value. Heptane (1.9), normal hexane (1.9), cyclohexane (2.0), benzene (2.3), toluene (2.4).
  • dielectric constant at 20 ° C. As a method for measuring the dielectric constant at 20°C, for example, a dielectric constant test conforming to 23 of JISC 2101:1999 and carried out at a measurement temperature of 20°C can be mentioned.
  • the content of the hydrocarbon-based solvent in the mixed liquid is 50 parts by mass or more and 500 parts by mass or less with respect to the total mass of 100 parts by mass of the first polymerizable monomer. It is preferable because the particle diameter can be easily controlled, the porosity can be easily increased while maintaining the strength of the hollow particles, and the amount of residual hydrocarbon solvent in the particles can be easily reduced.
  • the content of the hydrocarbon-based solvent in the mixed liquid is more preferably 60 parts by mass or more and 400 parts by mass or less, more preferably 70 parts by mass with respect to 100 parts by mass of the total mass of the first polymerizable monomer. It is from 80 parts by mass to 300 parts by mass, more preferably from 80 parts by mass to 200 parts by mass.
  • the dispersion stabilizer is an agent that disperses droplets of the monomer composition in the aqueous medium in the suspension step.
  • it is easy to control the particle size of the droplets in the suspension, the particle size distribution of the obtained hollow particles can be narrowed, and the strength of the hollow particles is improved by suppressing the shell from becoming too thin. From the viewpoint of suppressing the decrease, it is preferable to use an inorganic dispersion stabilizer as the dispersion stabilizer.
  • inorganic dispersion stabilizers examples include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide.
  • inorganic compounds such as oxides; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide and ferric hydroxide; These inorganic dispersion stabilizers can be used singly or in combination of two or more.
  • poorly water-soluble inorganic metal salts such as sulfates, carbonates, phosphates and metal hydroxides are preferred, metal hydroxides are more preferred, and magnesium hydroxide is particularly preferred.
  • the poorly water-soluble inorganic metal salt is preferably an inorganic metal salt having a solubility of 0.5 g or less in 100 g of water.
  • a poorly water-soluble inorganic dispersion stabilizer is dispersed in an aqueous medium in the form of colloidal particles, that is, a colloidal dispersion containing the poorly water-soluble inorganic dispersion stabilizer colloidal particles.
  • the colloidal dispersion containing the sparingly water-soluble inorganic dispersion stabilizer colloidal particles includes, for example, at least one selected from alkali metal hydroxides and alkaline earth metal hydroxides, and a water-soluble polyvalent metal salt (hydroxide excluding alkaline earth metal salts) in an aqueous medium.
  • Alkali metal hydroxide salts include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like.
  • Alkaline earth metal hydroxides include barium hydroxide and calcium hydroxide.
  • the water-soluble polyvalent metal salt may be any water-soluble polyvalent metal salt other than the compounds corresponding to the alkaline earth metal hydroxides. Examples include magnesium chloride, magnesium phosphate, magnesium sulfate, and the like.
  • magnesium metal salts such as calcium chloride, calcium nitrate, calcium acetate and calcium sulfate; aluminum metal salts such as aluminum chloride and aluminum sulfate; barium salts such as barium chloride, barium nitrate and barium acetate; zinc chloride and zinc nitrate , zinc salts such as zinc acetate; Among these, magnesium metal salt, calcium metal salt, and aluminum metal salt are preferred, magnesium metal salt is more preferred, and magnesium chloride is particularly preferred.
  • the water-soluble polyvalent metal salts can be used either singly or in combination of two or more.
  • the method of reacting at least one selected from the alkali metal hydroxides and alkaline earth metal hydroxides described above with the water-soluble polyvalent metal salt described above in an aqueous medium is not particularly limited.
  • a method of mixing an aqueous solution of at least one selected from alkali metal salts and alkaline earth metal hydroxides with an aqueous solution of a water-soluble polyvalent metal salt can be mentioned.
  • the content of the dispersion stabilizer is not particularly limited, but is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the total mass of the first polymerizable monomer and the hydrocarbon solvent. It is preferably 1.0 to 8.0 parts by mass.
  • the content of the dispersion stabilizer is equal to or higher than the above lower limit, the droplets of the monomer composition can be sufficiently dispersed so as not to coalesce in the suspension.
  • the content of the dispersion stabilizer is equal to or less than the above upper limit, it is possible to prevent the viscosity of the suspension from increasing during granulation, and to avoid the problem of the suspension clogging the granulator. can.
  • the content of the dispersion stabilizer is usually 2 parts by mass or more and 15 parts by mass or less, preferably 3 parts by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the aqueous medium.
  • the aqueous medium means a medium selected from the group consisting of water, hydrophilic solvents, and mixtures of water and hydrophilic solvents.
  • the hydrophilic solvent in the present disclosure is not particularly limited as long as it mixes well with water and does not cause phase separation.
  • hydrophilic solvents include alcohols such as methanol and ethanol; tetrahydrofuran (THF); dimethylsulfoxide (DMSO) and the like.
  • aqueous media it is preferable to use water because of its high polarity.
  • a liquid mixture is obtained by mixing each of the above-mentioned materials and other materials as necessary and stirring them appropriately.
  • an oil containing a lipophilic material such as (A) the first polymerizable monomer, (B) a polar component, (C) an oil-soluble polymerization initiator, and (D) a hydrocarbon solvent
  • the phase is dispersed in an aqueous phase containing (E) a dispersion stabilizer and (F) an aqueous medium with a particle size of about several millimeters.
  • the state of dispersion of these materials in the mixed liquid can be observed with the naked eye depending on the type of material.
  • the mixed solution may be obtained by simply mixing each of the above-mentioned materials and other materials as necessary and stirring them as appropriate. It is preferred that an oil phase containing a polar monomer, a polar component and a hydrocarbon solvent and an aqueous phase containing a dispersion stabilizer and an aqueous medium are separately prepared in advance and mixed to prepare a mixed solution. .
  • a colloidal dispersion obtained by dispersing a sparingly water-soluble inorganic dispersion stabilizer in the form of colloidal particles in an aqueous medium can be preferably used as the aqueous phase.
  • Suspension step is a step of preparing a suspension in which droplets of a monomer composition containing a hydrocarbon solvent are dispersed in an aqueous medium by suspending the mixed solution described above. is.
  • the suspension method for forming droplets of the monomer composition is not particularly limited.
  • Product name horizontal in-line disperser such as Cavitron; manufactured by IKA; product name: vertical in-line disperser such as DRS 2000/5; K. Homomixer MARK II type, etc.
  • droplets of the monomer composition containing the lipophilic material and having a particle size of about 1 to 60 ⁇ m are uniformly dispersed in the aqueous medium.
  • Such droplets of the monomer composition are difficult to observe with the naked eye, and can be observed with a known observation instrument such as an optical microscope.
  • a known observation instrument such as an optical microscope.
  • the hydrocarbon-based solvent with low polarity tends to collect inside the droplets.
  • the obtained droplets have the hydrocarbon solvent distributed inside and the material other than the hydrocarbon solvent distributed around the periphery.
  • FIG. 2 is a schematic diagram showing one embodiment of the suspension in the suspension process.
  • a droplet 10 of the monomer composition in FIG. 2 is schematically shown in cross section. Note that FIG. 2 is only a schematic diagram, and the suspension in the present disclosure is not necessarily limited to that shown in FIG. Part of FIG. 2 corresponds to (2) of FIG. 1 described above.
  • FIG. 2 shows how droplets 10 of the monomer composition and the first polymerizable monomer 4 c dispersed in the aqueous medium 1 are dispersed in the aqueous medium 1 . Droplet 10 is formed by surrounding oil-soluble monomer composition 4 with dispersion stabilizer 3 .
  • the monomer composition contains an oil-soluble polymerization initiator 5, as well as a first polymerizable monomer and a hydrocarbon solvent (none of which are shown).
  • the droplets 10 are fine oil droplets containing the monomer composition 4, and the oil-soluble polymerization initiator 5 generates polymerization initiation radicals inside the fine oil droplets. Therefore, precursor particles having a desired particle size can be produced without excessively growing fine oil droplets.
  • an oil-soluble polymerization initiator there is no opportunity for the polymerization initiator to come into contact with the polymerizable monomer 4c dispersed in the aqueous medium 1. Therefore, by using an oil-soluble polymerization initiator, it is possible to suppress the by-production of excessive resin particles such as solid particles having a relatively small particle size in addition to the target resin particles having hollow portions.
  • the polymerization step is carried out in two stages.
  • the first polymerization reaction is performed by subjecting the suspension to a polymerization reaction until the polymerization conversion rate of the first polymerizable monomer reaches 93% by mass or more.
  • a first precursor composition is prepared comprising first precursor particles having a shell comprising a polymer of polymerizable monomers and a hollow space filled with a hydrocarbon solvent.
  • the droplets of the monomer composition containing the hydrocarbon-based solvent are subjected to the polymerization reaction, so that the polymerization reaction easily progresses while maintaining the shape.
  • the size and porosity of the obtained hollow particles can be easily adjusted by adjusting the amount of the hydrocarbon solvent, the amount of the polar component, the type of the dispersion stabilizer, and the like. be able to.
  • the polarity of the hydrocarbon-based solvent is low with respect to the shell of the first precursor particles, and the hydrocarbon-based solvent serves as the shell. Since it is difficult to adapt to the , phase separation is likely to occur sufficiently, resulting in only one hollow portion.
  • the polymerization system is not particularly limited, and for example, a batch system (batch system), a semi-continuous system, a continuous system, or the like can be employed.
  • the polymerization temperature is preferably 40-80°C, more preferably 50-70°C.
  • the rate of temperature rise when raising the temperature to the polymerization temperature is preferably 10° C./h to 60° C./h, more preferably 15° C./h to 55° C./h.
  • the reaction time of the first polymerization reaction is preferably 0.5 to 5 hours, more preferably 1 to 3 hours.
  • the first polymerization reaction is carried out until the polymerization conversion rate of the first polymerizable monomer reaches 93% by mass or more, preferably 95% by mass or more, more preferably 97% by mass or more, More preferably, it is carried out until it reaches 99% by mass or more.
  • the polymerization conversion rate is defined as the mass of the solid content of the first precursor particles obtained by the first polymerization reaction, and the amount of the first polymerizable monomer remaining unreacted after the first polymerization reaction. It is obtained from the following formula (A) from the mass of the body.
  • the solid content is all components except the solvent, and the liquid polymerizable monomer and the like are included in the solid content.
  • the mass of the unreacted first polymerizable monomer can be measured using gas chromatography (GC).
  • Polymerization conversion rate (mass%) 100 - (mass of unreacted first polymerizable monomer/mass of solid content of first precursor particles) x 100 Formula (A)
  • the first precursor composition obtained in the first polymerization step has a solubility of 0.3 g/L or more in distilled water at 20°C.
  • a shell containing a polymer of the first polymerizable monomer and the second polymerizable monomer, and carbonization A second precursor composition is prepared that includes second precursor particles having a hollow space filled with a hydrogen-based solvent.
  • the polymerization reaction proceeds with the second polymerizable monomer incorporated into the shell of the first precursor particles.
  • the shell of the first precursor particles remained unreacted in the shell because the incorporation of the second polymerizable monomer promotes thermal movement. It is presumed that the polymerizable functional group of the first polymerizable monomer and the polymerization reaction of the second polymerizable monomer proceed to form a dense crosslinked structure.
  • the second polymerizable monomer is not particularly limited as long as it is a polymerizable monomer having a solubility of 0.3 g/L or more in distilled water at 20°C. From the viewpoint of reducing the modulus and dielectric loss tangent and improving the strength of the hollow particles, a non-crosslinking monomer having a solubility of 0.3 g / L or more in distilled water at 20 ° C., that is, a hydrophilic non-crosslinking monomer Ammers are preferred.
  • the hydrophilic non-crosslinking monomer used as the second polymerizable monomer include the same hydrophilic non-crosslinking monomers that can be used as the first polymerizable monomer. be able to.
  • (meth)acrylic acid alkyl esters having an alkyl group having 1 to 5 carbon atoms, (meth ) At least one selected from the group consisting of nitrile acrylate, derivatives thereof, and polar group-containing non-crosslinkable monomers is preferred.
  • the number of carbon atoms in the alkyl group of the (meth)acrylic acid alkyl esters is preferably 1-4, more preferably 1-3.
  • methyl (meth)acrylate is particularly preferable.
  • epoxy group-containing monomers epoxy group-containing monomers, hydroxyl group-containing monomers, and amino group-containing monomers are preferred.
  • Glycidyl (meth)acrylate is preferred as the epoxy group-containing monomer as the polar group-containing non-crosslinkable monomer, and 2-hydroxyethyl methacrylate is preferred as the hydroxyl group-containing monomer.
  • a hydrophilic crosslinkable monomer having a solubility of 0.3 g/L or more in distilled water at 20° C. can also be used.
  • the hydrophilic crosslinkable monomer used as the second polymerizable monomer include the same hydrophilic crosslinkable monomers that can be used as the first polymerizable monomer. .
  • a hydrophilic crosslinkable monomer containing a hydroxyl group or an amino group is preferable.
  • hydrophilic crosslinkable monomer containing a hydroxyl group for example, 2-hydroxy-3-methacrylpropyl acrylate can be preferably used, and as the hydrophilic crosslinkable monomer containing an amino group, diallylamine is preferably used. can be used.
  • the second polymerizable monomer the second polymerizable monomer is easily incorporated into the shell of the first precursor particles to promote thermal motion, and the strength of the hollow particles is improved. , preferably 2 g/L or more, more preferably 10 g/L or more, still more preferably 15 g/L or more, in distilled water at 20°C.
  • the upper limit of the solubility of the second polymerizable monomer in distilled water at 20° C. is not particularly limited, it is usually 80 g/L or less.
  • the second polymerizable monomer is incorporated into the shell of the first precursor particles to facilitate thermal motion, thereby reducing the CTE, dielectric constant and dielectric loss tangent of the hollow particles and increasing the strength of the hollow particles.
  • the molecular weight of the second polymerizable monomer is preferably 200 or less, more preferably 100 or less, from the viewpoint of easy improvement.
  • the lower limit of the molecular weight of the second polymerizable monomer is not particularly limited, and is usually 50 or more.
  • the amount of the second polymerizable monomer to be added is preferably 3 to 15 parts by mass, more preferably 4 to 10 parts by mass, per 100 parts by mass of the first polymerizable monomer.
  • the amount of the second polymerizable monomer added is at least the above lower limit, the effect of promoting the polymerization reaction by the addition of the second polymerizable monomer is improved, and the crosslinked structure of the shell of the hollow particles is formed.
  • the denser particles reduce the CTE, dielectric constant and dielectric loss tangent of the hollow particles and improve the strength of the hollow particles.
  • the amount of the second polymerizable monomer to be added is equal to or less than the above upper limit, the decrease in the content ratio of the first polymerizable monomer to the total polymerizable monomers used for forming the shell is suppressed. be able to. Since the first polymerizable monomer contains a large amount of the crosslinkable monomer, a crosslinked structure formed by the crosslinkable monomer can be formed by suppressing a decrease in the content of the first polymerizable monomer. It is possible to obtain hollow particles containing a large amount and having excellent strength.
  • the polymerization system is not particularly limited, and for example, the same polymerization system as used in the first polymerization reaction can be employed.
  • the polymerization temperature is preferably 40-80°C, more preferably 50-70°C.
  • the reaction time of the second polymerization reaction is preferably 1 to 6 hours, more preferably 2 to 4 hours.
  • the residual amount of unreacted polymerizable monomers after the second polymerization reaction can be preferably 750 ppm or less, more preferably 500 ppm or less, still more preferably 300 ppm or less.
  • the residual amount of unreacted polymerizable monomers after the second polymerization reaction refers to the solid content mass of the hollow particles obtained by the second polymerization reaction. is the mass ratio of the monomer.
  • the mass of the unreacted polymerizable monomer can be measured using gas chromatography (GC).
  • Solid-liquid separation step In this step, solid-liquid separation is performed on the second precursor composition containing hollow particles (second precursor particles) containing a hydrocarbon solvent obtained by the polymerization step described above. This is a step of obtaining a solid content containing the second precursor particles.
  • a method for solid-liquid separation of the second precursor composition is not particularly limited, and a known method can be used.
  • the solid-liquid separation method include centrifugation, filtration, static separation, etc. Among them, centrifugation or filtration can be employed. may be adopted.
  • an optional step such as a pre-drying step may be carried out before carrying out the below-described solvent removal step.
  • the pre-drying step include a step of pre-drying the solid content obtained after the solid-liquid separation step using a drying device such as a dryer or a drying device such as a hand dryer.
  • Solvent removal step This step is a step of removing the hydrocarbon-based solvent included in the hollow particles (second precursor particles) obtained in the solid-liquid separation step. By removing the hydrocarbon-based solvent contained in the second precursor particles in air, the hydrocarbon-based solvent inside the second precursor particles is replaced with air, and hollow particles filled with gas are obtained. be done.
  • the term “in air” in this step means an environment in which no liquid exists outside the second precursor particles, and a hydrocarbon-based solvent is removed from the outside of the second precursor particles. It means an environment where there is only a very small amount of liquid that does not affect the "In air” can be rephrased as a state in which the second precursor particles are not present in the slurry, or can be rephrased as a state in which the second precursor particles are present in the dry powder. That is, in this step, it is important to remove the hydrocarbon-based solvent in an environment where the second precursor particles are in direct contact with the external gas.
  • a method for removing the hydrocarbon-based solvent in the second precursor particles in the air is not particularly limited, and a known method can be adopted.
  • the method include a vacuum drying method, a heat drying method, a flash drying method, or a combination of these methods.
  • the heating temperature must be higher than the boiling point of the hydrocarbon-based solvent and lower than the highest temperature at which the shell structure of the second precursor particles does not collapse. Therefore, depending on the composition of the shell in the second precursor particles and the type of hydrocarbon solvent, for example, the heating temperature may be 50 to 200°C, 70 to 200°C, or 100 to 200°C. good. Due to the drying operation in air, the hydrocarbon-based solvent inside the second precursor particles is replaced by the external gas, resulting in hollow particles in which the hollow portion is filled with gas.
  • the drying atmosphere is not particularly limited, and can be appropriately selected depending on the use of the hollow particles. Air, oxygen, nitrogen, argon, etc. can be considered as the dry atmosphere, for example. Further, hollow particles whose insides are temporarily vacuumed can also be obtained by once filling the insides of the hollow particles with gas and then drying them under reduced pressure.
  • the second precursor may be removed by replacing the hydrocarbon solvent contained in the particles with the aqueous medium of the slurry.
  • an inert gas through the second precursor composition at a temperature equal to or higher than the boiling point of the hydrocarbon-based solvent minus 35°C, carbonization included in the second precursor particles is performed.
  • a hydrogen-based solvent can be removed.
  • the boiling point of the hydrocarbon-based solvent in the solvent removal step is It is the boiling point of the solvent with the highest boiling point among the solvents used, that is, the highest boiling point among a plurality of boiling points.
  • the temperature at which the inert gas is bubbled through the second precursor composition is higher than the temperature obtained by subtracting 30°C from the boiling point of the hydrocarbon solvent in order to reduce the residual amount of the hydrocarbon solvent in the hollow particles. It is preferably the temperature, and more preferably the temperature is equal to or higher than the temperature minus 20°C.
  • the temperature during bubbling is usually a temperature equal to or higher than the polymerization temperature in the polymerization step.
  • the temperature during bubbling may be 50° C. or higher and 100° C. or lower.
  • the bubbling inert gas is not particularly limited, but examples thereof include nitrogen and argon.
  • the bubbling conditions are appropriately adjusted according to the type and amount of the hydrocarbon solvent so that the hydrocarbon solvent contained in the second precursor particles can be removed.
  • the gas may be bubbled in an amount of 1-3 L/min for 1-10 hours.
  • an aqueous slurry in which the aqueous medium is included in the second precursor particles is obtained.
  • the hollow particles obtained by solid-liquid separation of this slurry are dried to remove the aqueous medium in the hollow particles, thereby obtaining hollow particles in which the hollow portion is filled with gas.
  • the hydrocarbon-based solvent in the second precursor particles is removed in air to obtain hollow particles whose hollow portions are filled with gas.
  • the latter method has the advantage that the residual hydrocarbon solvent can be reduced by bubbling with an inert gas.
  • the hydrocarbon-based solvent contained in the second precursor particles is replaced with water, if the same volume of water as the hydrocarbon-based solvent that escapes from the particles does not enter the particles, the obtained hollow resin particles There is a problem of collapsing. As means for preventing this, it is conceivable, for example, to adjust the pH of the slurry to 7 or higher, and then remove the hydrocarbon-based solvent after the shells of the particles are swollen with an alkali. In this case, since the shell of the particle acquires flexibility, the replacement of the hydrocarbon-based solvent and water inside the particle progresses rapidly.
  • the hydrophobic organic solvent contained in the precursor particles is removed without solid-liquid separation of the slurry-like precursor composition obtained in the polymerization step.
  • a method for example, under a predetermined pressure (high pressure, normal pressure or reduced pressure), a method of evaporating and distilling the hydrophobic organic solvent included in the precursor particles from the precursor composition; under a predetermined pressure (high pressure a method of introducing an inert gas such as nitrogen, argon, or helium or water vapor into the precursor composition under atmospheric pressure, normal pressure, or reduced pressure to evaporate it.
  • (6-a) Washing step The washing step is to remove the dispersion stabilizer remaining in the second precursor composition containing the second precursor particles before the solid-liquid separation step. This is a step of washing by adding an alkali.
  • the dispersion stabilizer used is an acid-soluble inorganic dispersion stabilizer, it is preferable to wash by adding an acid to the second precursor composition containing the second precursor particles.
  • the dispersion stabilizer used is an alkali-soluble inorganic compound, it is preferable to add an alkali to the second precursor composition containing the second precursor particles for washing.
  • the acid is added to the second precursor composition containing the second precursor particles, and the pH is adjusted to preferably 6.5. Below, it is preferable to adjust to 6 or less, more preferably.
  • inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as formic acid and acetic acid can be used. , in particular sulfuric acid, is preferred.
  • the hollow portion re-replacement step is a step of replacing the gas or liquid inside the hollow particles with another gas or liquid.
  • the environment inside the hollow particles can be changed, molecules can be selectively confined inside the hollow particles, and the chemical structure inside the hollow particles can be modified according to the application.
  • the hollow particles of the present disclosure are excellent in strength, so they are not easily crushed during kneading with other materials and during molding after kneading. Since it has excellent effects as a vibration damping material, etc., it is suitable as an additive for molded articles, and is particularly preferably used as an additive for molded articles made of resin.
  • the hollow particles of the present disclosure are, for example, a molded body formed using a thermoplastic or thermosetting resin, and a material containing a thermoplastic or thermosetting resin and an organic or inorganic fiber. It can also be contained as a filler in the molded article.
  • hollow particles of the present disclosure include, for example, members such as light reflecting materials, heat insulating materials, sound insulating materials, and low dielectric materials used in various fields such as automobiles, electricity, electronics, construction, aviation, and space, and food containers. , Sports shoes, footwear such as sandals, home appliance parts, bicycle parts, stationery, tools, filaments for 3D printers, etc.
  • the hollow particles of the present disclosure have a low CTE, a low dielectric constant and a low dielectric loss tangent, and are therefore suitably used as additives for resin compositions used in the fields of electricity or electronics.
  • the hollow particles of the present disclosure are suitably used as a material for an electronic circuit board.
  • the hollow particles of the present disclosure can also be used as interlayer insulating materials, dry film resists, solder resists, bonding wires, magnet wires, semiconductor sealing materials, epoxy sealing materials, mold underfills, underfills, die bond pastes, It is also suitably used as an additive in semiconductor materials such as buffer coat materials, copper-clad laminates, flexible substrates, high-frequency device modules, antenna modules, and in-vehicle radars.
  • the hollow particles of the present disclosure have a high porosity, are resistant to crushing, and have excellent heat resistance. It also satisfies the required heat resistance.
  • the hollow particles of the present disclosure are also useful as plastic pigments with excellent gloss, hiding power, and the like.
  • the hollow particles of the present disclosure can enclose useful ingredients such as fragrances, chemicals, agricultural chemicals, and ink ingredients inside by means of immersion treatment, reduced pressure or pressure immersion treatment, etc. Therefore, various It can be used for various purposes.
  • the resin composition of the present disclosure is characterized by containing the hollow particles of the present disclosure and a matrix resin.
  • the resin composition of the present disclosure is generally obtained by mixing or kneading the hollow particles of the present disclosure, a matrix resin, and additives added as necessary, and is, for example, a pellet.
  • the hollow particles of the present disclosure are less likely to be crushed during mixing or kneading and subsequent molding. effect is exhibited.
  • the matrix resin used in the resin composition of the present disclosure is not particularly limited, it is preferably a thermoplastic resin or a thermosetting resin.
  • the thermoplastic resin a known one can be used and is not particularly limited, but examples include polyolefins such as polypropylene and polyethylene; polyamides such as PA6, PA66 and PA12; Ether ketone ketone, polyvinyl chloride, polystyrene, poly(meth)acrylate, polycarbonate, polyvinylidene fluoride, acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), polyphenylene ether, polyphenylene sulfide, polyester, polytetra Examples include fluoroethylene, thermoplastic elastomers, and the like.
  • thermoplastic resins can be used alone or in combination of two or more.
  • thermosetting resin known ones can be used, and there is no particular limitation, but for example, phenolic resin, melamine resin, urea resin, unsaturated polyester resin, epoxy resin, polyurethane resin.
  • thermosetting resins silicon-based resins, alkyd-based resins, thermosetting modified polyphenylene ether-based resins, thermosetting polyimide-based resins, benzoxazine-based resins, urea-based resins, allyl-based resins, aniline-based resins, maleimide-based resins, bismaleimide triazine-based resins
  • thermosetting resins can be used alone or in combination of two or more.
  • the thermosetting resin is preferably used together with additives for curing the resin, such as curing agents and curing catalysts.
  • the curing agent and curing catalyst known ones can be used, and they may be appropriately selected according to the type of resin. , benzoxazines, cyanate esters, and carbodiimides. Moreover, when the resin composition of the present disclosure contains a thermosetting resin, it may further contain a solvent or the like for dissolving or dispersing each component, if necessary.
  • the matrix resin is preferably an insulating resin.
  • the insulating resin is not particularly limited, and examples include epoxy resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, silicon resins, benzoxazine resins, melamine resins, urea resins, Examples include allyl-based resins, phenol-based resins, unsaturated polyester-based resins, polyurethane-based resins, aniline-based resins, and the like.
  • epoxy-based resins thermosetting polyimide-based resins, modified polyphenylene ether-based resins, silicon-based resins, benzoxazine-based resins, and melamine-based resins are suitable.
  • These insulating resins may be used alone, or two or more of them may be used in combination.
  • the content of the matrix resin in 100% by mass of the total mass of the resin composition of the present disclosure is not particularly limited, but is preferably 50 to 95% by mass.
  • the content of the matrix resin is at least the above lower limit, the resin composition is excellent in moldability when formed into a molded article, and the obtained molded article is excellent in mechanical strength.
  • the content of the matrix resin is equal to or less than the above upper limit, the hollow particles of the present disclosure can be sufficiently contained, so that the hollow particles of the present disclosure contribute to weight reduction, low CTE, Performance such as low dielectric constant can be imparted.
  • the content of the matrix resin includes the content of additives for curing the resin, such as curing agents and curing catalysts. .
  • the content of the hollow particles of the present disclosure is not particularly limited, it is preferably 5 to 50 wt% in the total mass of 100 mass% of the resin composition of the present disclosure.
  • the hollow particles of the present disclosure can impart properties such as weight reduction, CTE reduction, and dielectric constant reduction to the resin composition.
  • the content of the hollow particles is equal to or less than the above upper limit, the matrix resin can be sufficiently contained, so that moldability and mechanical strength can be improved.
  • the resin composition of the present disclosure contains, in addition to the hollow particles and the matrix resin of the present disclosure, additives such as ultraviolet absorbers, colorants, heat stabilizers, fillers, etc., as necessary within a range that does not impair the effects of the present disclosure. or may further contain a solvent or the like.
  • the resin composition of the present disclosure may further contain organic or inorganic fibers such as carbon fibers, glass fibers, aramid fibers and polyethylene fibers.
  • the resin composition of the present disclosure can be obtained, for example, by mixing the hollow particles of the present disclosure, a matrix resin, and additives, solvents, etc. added as necessary.
  • the matrix resin in the resin composition of the present disclosure is a thermoplastic resin
  • the hollow particles of the present disclosure and, if necessary, additives are added to the molten thermoplastic resin and melted. You may mix by kneading.
  • the resin composition of the present disclosure obtained in this way may be a liquid resin composition, and the resin composition of the present disclosure is a resin molded product obtained by molding the liquid resin composition by a known method. good too.
  • the resin composition of the present disclosure can be used as a molded article.
  • the molding of the resin composition of the present disclosure effectively exhibits the effects of the hollow particles of the present disclosure, such as weight reduction, CTE reduction, and dielectric constant reduction.
  • the resin composition of the present disclosure contains a thermoplastic resin as a matrix resin and is a liquid resin composition obtained by melting the resin, the liquid resin composition is subjected to extrusion molding, injection molding, press molding, A molded body can be obtained by molding into a desired shape by a known molding method such as compression molding.
  • the resin composition of the present disclosure is a liquid resin composition in which hollow particles or the like are contained in a liquid matrix resin before the curing reaction, or a liquid resin composition in which each component is dissolved or dispersed in a solvent
  • a molded body can be obtained by coating the liquid resin composition on a support, and drying and curing as necessary.
  • the material of the support include resins such as polyethylene terephthalate and polyethylene naphthalate; and metals such as copper, aluminum, nickel, chromium, gold and silver.
  • a known method can be used, and examples thereof include dip coating, roll coating, curtain coating, die coating, slit coating, gravure coating and the like.
  • the drying temperature is preferably a temperature at which the matrix resin is not cured, and is generally 20°C or higher and 200°C or lower, preferably 30°C or higher and 150°C or lower.
  • the drying time is usually 30 seconds to 1 hour, preferably 1 minute to 30 minutes.
  • the curing reaction of the resin composition is carried out according to the type of matrix resin, and is not particularly limited. When a matrix resin that is cured by heating is included, the heating temperature for the curing reaction is appropriately adjusted according to the type of resin, and is not particularly limited, but is usually 30° C. or higher and 400° C. or lower, preferably 70° C. or higher. 300° C.
  • the curing time is 5 minutes or more and 5 hours or less, preferably 30 minutes or more and 3 hours or less.
  • the heating method is not particularly limited, and may be performed using, for example, an electric oven.
  • the matrix resin contained in the liquid resin composition obtained by dissolving or dispersing each component in a solvent may be a thermosetting resin or a thermoplastic resin.
  • the shape of the molded body is not particularly limited, and can be various shapes that can be molded using the resin composition of the present disclosure. Any shape such as a three-dimensional shape can be used.
  • the fibers in the molded article may be in the form of a non-woven fabric.
  • the molded article may be a molded article of a resin composition obtained by adding the hollow particles of the present disclosure to the fiber-reinforced plastic containing the resin and fibers as described above.
  • the resin composition of the present disclosure includes, for example, light reflecting materials, heat insulating materials, sound insulating materials and low dielectric materials used in various fields such as automobiles, electricity, electronics, construction, aviation, and space. Examples include containers, sports shoes, footwear such as sandals, household appliance parts, bicycle parts, stationery, and tools. Since the resin composition of the present disclosure has a low CTE, a low dielectric constant and a low dielectric loss tangent, it is particularly suitable for use in insulating resin layers used in the fields of electricity or electronics.
  • Example 1 (1) Mixed Solution Preparation Step First, the following materials were mixed to form an oil phase.
  • First polymerizable monomer 80 parts of ethylene glycol dimethacrylate and 20 parts of pentaerythritol tetraacrylate 2,2'-azobis (2,4-dimethylvaleronitrile) (oil-soluble polymerization initiator, manufactured by Wako Pure Chemical Industries, Ltd., Product name: V-65) 3 parts Rosic acid 0.007 parts Cyclohexane 120 parts
  • Second polymerizable monomer 80 parts of ethylene glycol dimethacrylate and 20 parts of pentaerythritol tetraacrylate 2,2'-azobis (2,4-dimethylvaleronitrile) (oil-soluble polymerization initiator, manufactured by Wako Pure Chemical Industries, Ltd., Product name: V-65) 3 parts Rosic acid 0.007 parts Cyclohexane 120 parts
  • 17.1 parts of magnesium chloride water-soluble polyvalent metal salt
  • Solvent removal step The second precursor particles obtained in the solid-liquid separation step are heat-treated in a vacuum dryer under vacuum conditions at 200°C for 6 hours, thereby encapsulating the particles. Hollow particles of Example 1 were obtained by removing the hydrocarbon solvent. The obtained hollow particles were confirmed to be spherical and to have hollow portions from the results of scanning electron microscope observation and porosity values.
  • Example 2 In Example 1, except that the material of the second polymerizable monomer added in the above "(3) Polymerization step" was as shown in Table 1, the procedure was the same as in Example 1, and Examples 2 to 3 and 8 hollow particles were produced.
  • Example 4 In Example 1, the same procedure as in Example 1 was performed except that the material and amount of the first polymerizable monomer were as shown in Table 1 in the above "(1) mixed liquid preparation step". Hollow particles of Example 4 were produced.
  • Example 5-6 In Example 1, except that the amount of the second polymerizable monomer added in the above "(3) polymerization step" was as shown in Table 1, the procedure was the same as in Example 1, Examples 5 to 5 6 hollow particles were produced.
  • Example 7 In Example 1, the material and amount of the first polymerizable monomer and the material and amount of the hydrocarbon-based solvent were as shown in Table 1 in the above "(1) mixed liquid preparation step", Hollow particles of Example 7 were produced in the same procedure as in Example 1.
  • Example 1 In Example 1, in the above “(3) polymerization step", except that the second polymerizable monomer was not added and the second polymerization reaction was not performed, the procedure was the same as in Example 1. Comparative Hollow particles of Example 1 were produced.
  • Example 2 In Example 1, in the above "(3) Polymerization step", 5 parts of styrene (solubility in distilled water at 20°C: 0.2 g/L) was used instead of 5 parts of methyl acrylate as the second polymerizable monomer. Hollow particles of Comparative Example 2 were produced in the same manner as in Example 1, except for adding
  • Comparative Example 3 In Example 1, the hollow particles of Comparative Example 3 were prepared in the same procedure as in Example 1, except that the amount of the hydrocarbon-based solvent was changed as shown in Table 1 in the above "(1) mixed liquid preparation step". manufactured.
  • Example 4 In Example 1, the material and amount of the first polymerizable monomer were as shown in Table 1 in the above "(1) Mixture preparation step", and the second polymer in the above "(3) Polymerization step". Hollow particles of Comparative Example 4 were produced in the same procedure as in Example 1, except that no polymerizable monomer was added and the second polymerization reaction was not performed.
  • Example 5 In Example 1, the material and amount of the first polymerizable monomer and the material and amount of the hydrocarbon-based solvent were as shown in Table 1 in the above "(1) mixed liquid preparation step", and the above "( Hollow particles of Comparative Example 5 were produced in the same procedure as in Example 1, except that the second polymerizable monomer was not added and the second polymerization reaction was not performed in 3) Polymerization step. .
  • Polymerization conversion rate (mass%) 100 - (mass of unreacted first polymerizable monomer/mass of solid content of first precursor particles) x 100 Formula (A) ⁇ GC conditions>
  • Table 2 shows the content ratio (% by mass) of each monomer unit in the polymer contained in the shell for the hollow particles obtained in each example and each comparative example. Further, the hollow particles obtained in each example and each comparative example were subjected to the following measurements and evaluations. Table 2 shows the results.
  • volume average particle size of hollow particles The particle size of hollow particles is measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, trade name: SALD-2000), and the volume average is calculated. particle size.
  • the hollow particles obtained in each comparative example have a CTE at 80 to 200 ° C. and a CTE at 25 to 80 ° C. compared to the examples using the same type of crosslinkable monomer. It had a high dielectric constant and a high dielectric loss tangent at a frequency of 1 GHz.
  • the hollow particles obtained in Comparative Examples 1, 2, 4 and 5 10% by mass or more of the hollow particles precipitated in acetone in the above immersion test, and the shell density was insufficient. It is presumed that the modulus and dissipation factor were not sufficiently reduced.
  • Comparative Examples 1 and 5 since the second polymerizable monomer was not added, it is presumed that the denseness of the shell was insufficient.
  • Comparative Example 2 instead of a hydrophilic monomer having a solubility of 0.3 g/L or more in distilled water at 20°C as the second polymerizable monomer, a solubility in distilled water at 20°C was 0.2 g. /L of styrene was used, presumably resulting in insufficient shell density.
  • Comparative Example 4 methyl methacrylate was added to the mixture in one step together with the first polymerizable monomer instead of as the second polymerizable monomer, and the polymerization reaction was performed in one step. It is presumed that the shell became insufficiently dense.
  • Comparative Example 3 since the hollow particles obtained in Comparative Example 3 had a low porosity and an insufficient size of the hollow portion, it is presumed that the CTE, dielectric constant and dielectric loss tangent were not sufficiently reduced.
  • the hollow particles obtained in each example had low CTE at 80 to 200° C. and low CTE at 25 to 80° C., and low dielectric constant and dielectric loss tangent at a frequency of 1 GHz.
  • the hollow particles obtained in Examples 1 to 8 had a porosity of 50% or more and a sufficiently large proportion of the hollow portion in the particles, that is, the proportion of the shell in the particles was sufficiently reduced, and the shell However, it contains a polymer containing 70 to 100 parts by mass of crosslinkable monomer units in 100 parts by mass of the total monomer units, and the hollow particles that precipitate in acetone in the immersion test are less than 10% by mass. It is presumed that the CTE, relative permittivity and dielectric loss tangent were sufficiently reduced because of the dense structure.

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EP4299640A4 (en) * 2021-02-26 2025-04-30 Zeon Corporation Thermal conductivity regulating agent and molded body
CN116848161B (zh) * 2021-02-26 2025-10-28 日本瑞翁株式会社 中空颗粒
WO2023074651A1 (ja) * 2021-10-29 2023-05-04 日本ゼオン株式会社 中空粒子、中空粒子の製造方法、樹脂組成物、及び成形体

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