Hollow particles and methods for producing the same, and utilization of hollow particles

Abstract

Provided are: hollow particles with which the low dielectricity of an electrical material, which is obtained from a resin composition containing the hollow particles, can be achieved; a production method therefor; and a use of said hollow particles.　These hollow particles each have a layer composed of a silicone-based compound that contains: a total of 0.1-20 mol% of specified structural units having an amino group; and a total of 80-99.9 mol% of specified structural units not having an amino group.

Description

[Technical Field]

[0001] This invention relates to hollow particles, methods for producing the same, and the uses of hollow particles. [Background technology]

[0002] In recent years, in order to cope with the shift to 5G (high-speed networks) in the telecommunications industry, research has been conducted on developing resin materials with low transmission loss, that is, resin materials with low dielectric constant (Dk) and dielectric loss tangent (Df).

[0003] Methods for reducing the dielectric constant (low dielectric constant and low dielectric loss tangent) of resin materials include porous formation of the resin material using air with a Dk of 1, and the addition of hollow particles to the resin material.

[0004] The technology disclosed in Patent Document 1 achieves low dielectric constant of the interlayer insulating film by using a resin composition containing hollow silicone-based fine particles with a particle size of 10 to 1000 nm and polyimide or polytetrafluoroethylene. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2008 / 111393 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, there is room for improvement in reducing dielectric strength using conventional technologies.

[0007] One aspect of the present invention aims to provide hollow particles that can achieve low dielectric properties in electrical materials obtained from a resin composition containing hollow particles, a method for producing the same, and the use of the hollow particles. [Means for solving the problem]

[0008] One embodiment of the present invention includes the following aspects.

[0009] [1](a)R 1 SiO 3 / 2 units (where R 1 represents an alkyl group having 1 to 4 carbon atoms and having an amino group. The same applies hereinafter), R 1 Si(OH)O 2 / 2 units, and R 1 Si(OH)2O 1 / 2 a total of 0.1 to 20 mol% of one or more units selected from the group consisting of units, (b)R 2 SiO 3 / 2 units (where R 2 represents an alkyl group having 1 to 4 carbon atoms and not having an amino group. The same applies hereinafter), R 2 Si(OH)O 2 / 2 units, and R 2 Si(OH)2O 1 / 2 a total of 80 to 99.9 mol% of one or more units selected from the group consisting of units, hollow particles having a layer composed of a silicone-based compound containing

[0010] [2] Hollow particles having a layer composed of a silicone-based compound containing the following structural units (1) to (4), (1) and (2) in total are 0.1 to 20 mol%, (3) and (4) in total are 80 to 99.9 mol%, and the amount of Si-OSi(R 2 ) is 0.01 mmol / g or more, hollow particles: (1)R 1 SiO 3 / 2 units (where R 1 represents an alkyl group having 1 to 4 carbon atoms and having an amino group. The same applies hereinafter), R 1 Si(OH)O 2 / 2 units, and R 1 Si(OH)2O 1 / 2 one or more units selected from the group consisting of units; (2)R 1 Si(OSi(R 2 )3)O 2 / 2 units (where R 2Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 One or more units selected from a group of units; (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 One or more units selected from a group of units; (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 One or more units selected from a group of units.

[0011] [3] A method for producing a dispersion of hollow particles comprising the following steps: Step 1: A step of polymerizing acrylic monomers in an aqueous medium in the presence of a surfactant containing a cationic surfactant to produce particles containing an acrylic polymer; Step 2. On the surface of the particles containing the acrylic polymer obtained in Step 1, (a)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2A step of producing multilayer particles by arranging a condensate of silanes, which are raw materials for one or more units selected from a group of units, wherein the condensate contains a total of 0.1 to 20 mol% of one or more units described in (a) and a total of 80 to 99.9 mol% of one or more units described in (b); Step 3. A step to obtain a dispersion of hollow particles containing an organic solvent in the core, by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 2 using an organic solvent.

[0012] [4] A method for producing hollow particles comprising the following steps: Step 1. In the presence of a cationic surfactant, (1)R is applied to the surface of the particles containing the acrylic polymer. 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 A process for producing multilayer particles by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof; Step 2. A step to obtain hollow particles by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 1 using an organic solvent; Step 3. R constituting the hollow particles obtained in Step 2 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3Si(OH)2O 1 / 2 Reacting a sealing agent with one or more units selected from the group consisting of units, (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (wherein R 2 each represents the same or different alkyl group having 1 to 4 carbon atoms. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 Unit, (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Unit and R 3 Si(OSi(R 2 )3)2O 1 / 2 The step of sealing the hydroxyl groups to generate one or more units selected from the group consisting of units, (28) The total of (1) and (2) is 0.1 to 20 mol%, the total of (3) and (4) is 80 to 99.9 mol%, and the amount of Si-OSi(R 2 )3 is 0.01 mmol / g or more.

Advantages of the Invention

[0013] According to the hollow particles according to one aspect of the present invention, when dispersed in a matrix resin and used as a layer material such as a circuit board, the Dk of the layer material can be lowered.

[0014] The hollow particles according to another aspect of the present invention have a layer made of a silicone-based compound in which residual hydroxyl groups are sealed. Therefore, according to one aspect of the present invention, an electrical material obtained from a resin composition containing the hollow particles and a matrix resin can achieve very low Dk and Df.

Brief Description of the Drawings

[0015] [Figure 1] It is a TEM image for evaluating the presence or absence of intrusion of the matrix resin into the hollow particles of Example A2 and the dispersibility of the hollow particles. [Figure 2]These are TEM images used to evaluate whether the matrix resin penetrated the interior of the hollow particles in Comparative Example A2 and to assess the dispersibility of the hollow particles. [Modes for carrying out the invention]

[0016] One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents mentioned herein are incorporated herein by reference. Furthermore, unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)."

[0017] [Embodiment A] [1. Technical concept of Embodiment A of the present invention] While Patent Document 1 discloses insulating films using high molecular weight resins such as polyimide resins and fluororesins, it does not suggest whether insulating materials with a low dielectric constant can be obtained when using a matrix resin with a relatively low molecular weight before heat curing, such as epoxy resin. Furthermore, the hollow silicone particles in Patent Document 1 are hollowed out by first creating core-shell type particles and then removing the organic polymer from the core with an organic solvent. It is thought that the silicone compound of the shell has voids large enough for the organic polymer to diffuse through to the outside of the particle. Therefore, when using a resin with a relatively low molecular weight before heat curing, such as epoxy resin, as the matrix resin, there is a concern that the resin may penetrate into the hollow silicone particles, and the hollow portion may be partially or completely filled with the resin, preventing the acquisition of an insulating material with the expected low dielectric constant.

[0018] Embodiment A of the present invention has been made in view of the above problems, and its object is to disperse it in a matrix resin having a relatively low molecular weight before thermosetting, such as an epoxy resin, and when used as a layer material such as a circuit board, to provide hollow particles capable of reducing the dielectric constant of the layer material, particularly reducing the dielectric loss tangent.

[0019] As a result of intensive studies, the present inventors have found that when hollow particles having a layer made of a silicone-based compound containing an alkyl group having 1 to 4 carbon atoms and an amino group are dispersed in a matrix resin and used as a layer material such as a circuit board, the dielectric constant of the layer material can be lowered, and the present invention has been completed. The reason why the dielectric constant can be lowered is considered to be that the amino group reacts with the matrix resin and the structure of the layer covering the surface of the hollow particles becomes dense. As a result, the intrusion of the matrix resin into the core portion of the hollow particles is suppressed, and the non-hollowing of the hollow particles is suppressed. For the hollow particles according to Embodiment A of the present invention, the blending amount of the hollow particles in the matrix resin can be reduced, and while reducing the dielectric constant of the layer material, the strength and adhesion of the layer material can also be ensured. Incidentally, it is noted that Embodiment A of the present invention is not limited to the above-described presumed mechanism.

[0020] Generally, when an additive having a polar group is dispersed in a matrix resin and used as a layer material such as a circuit board, the layer material is considered to have a higher dielectric constant than when an additive having no polar group is added. The amino group is classified as a polar group. Therefore, it is surprising that the dielectric constant of the layer material could be lowered when hollow particles having an amino group were dispersed in a matrix resin and used as a layer material such as a circuit board.

[0021] [2. Hollow Particles] The hollow particles according to Embodiment A of the present invention are (a) R 1 SiO 3 / 2 units (wherein R 1 represents an alkyl group having 1 to 4 carbon atoms and having an amino group. The same shall apply hereinafter.), R 1 Si(OH)O 2 / 2 units, and R 1 Si(OH)2O1 / 2 One or more units selected from the group of units, totaling 0.1 to 20 mol%, (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 One or more units selected from the group of units, totaling 80-99.9 mol%, It has a layer made of a silicone-based compound containing [specific compound name].

[0022] (a) R 1 SiO 3 / 2 Examples of raw materials for the units include aminomethyltrimethoxysilane, aminomethyltriethoxysilane, aminomethyltripropoxysilane, aminoethyltrimethoxysilane, aminoethyltriethoxysilane, aminoethyltripropoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminopropyltripropoxysilane, aminobutyltrimethoxysilane, aminobutyltriethoxysilane, and aminobutyltripropoxysilane. For example, in the case of aminopropyltrimethoxysilane, examples include 3-aminopropyltrimethoxysilane.

[0023] (a) R 1 Si(OH)O 2 / 2 Units and R 1 Si(OH)2O 1 / 2 The unit is R, which is formed when the silanes used as raw materials undergo a condensation reaction after hydrolysis, leaving some hydroxyl groups unreacted. 1 SiO 3 / 2 This represents the unit used when a unit was not reached.

[0024] (b) R 2 SiO 3 / 2Examples of raw materials for the units include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, and butyltripropoxysilane.

[0025] (b) R 2 Si(OH)O 2 / 2 Units and R 2 Si(OH)2O 1 / 2 The unit is formed when the silanes used as raw materials undergo a condensation reaction after hydrolysis, and some hydroxyl groups remain unreacted, R 2 SiO 3 / 2 This represents the unit used when a unit was not reached.

[0026] According to the above configuration, since the unit of (a) has an alkyl group having 1 to 4 carbon atoms and an amino group, when hollow particles are dispersed in a matrix resin and used as a layer material for a circuit board or the like, the dielectric constant of the layer material can be lowered.

[0027] The lower limit of the proportion of (a) in the hollow particles is preferably 0.1 mol%, and more preferably 1 mol%. The upper limit of the proportion of (a) is preferably 20 mol%, and more preferably 15 mol%. If the proportion of (a) is less than 0.1 mol%, the number of amino groups is small, making it difficult to prevent the matrix resin from penetrating into the particle interior. If the proportion of (a) exceeds 20 mol%, the number of amino groups, which are polar groups, becomes too large, which may conversely hinder the low dielectric effect.

[0028] The lower limit of the proportion of (b) in the hollow particles is preferably 80 mol%, and more preferably 85 mol%. The upper limit of the proportion of (b) is preferably 99.9 mol%, and more preferably 99.0 mol%.

[0029] The hollow particles described above preferably have a particle diameter of 10 to 1000 nm. Particles smaller than 10 nm or larger than 1000 nm tend to be difficult to synthesize stably. In this invention, the particle diameter can be determined by first obtaining a TEM image of the particles, as in Example A described later, and then determining the outer diameter of the particles in the TEM image. More specifically, the outer diameter can be measured for each of 10 or more, more preferably 100 or more, and even more preferably 1000 or more particles, and the particle diameter can be determined as the average value of these measured values.

[0030] In this case, the dielectric properties of the layer material can be reduced, and the strength and flatness of the layer material are also good. The lower limit of the particle size is more preferably 20 nm, and even more preferably 30 nm. The upper limit of the particle size is more preferably 800 nm, and even more preferably 500 nm. When the particle size is within the above range, the strength and flatness of the layer material are further improved, and stable synthesis of particles becomes possible.

[0031] Preferably, the volume ratio of the internal space to the total volume of the hollow particles is 10 to 70%. If the volume ratio is less than 10%, the low dielectric effect of the layer material may not be sufficient. If the volume ratio exceeds 70%, the strength of the hollow particles themselves may be insufficient, and they may break during processing.

[0032] In this case, the dielectric properties of the layer material can be reduced, and the strength and adhesion of the layer material are also good. A lower limit of 15% in volume ratio is more preferable. A higher limit of 60% in volume ratio is more preferable.

[0033] [2. Method for producing a dispersion of hollow particles and a method for producing hollow particles] The method for producing hollow particles according to Embodiment A of the present invention is: Step 1: A step of polymerizing acrylic monomers in an aqueous medium in the presence of a surfactant containing a cationic surfactant to produce particles containing an acrylic polymer; Step 2. On the surface of the particles containing the acrylic polymer obtained in Step 1, (a)R 1 SiO 3 / 2 Unit (in the formula, R)1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 A step of producing multilayer particles by arranging a condensate of silanes, which are raw materials for one or more units selected from a group of units, wherein the condensate contains a total of 0.1 to 20 mol% of one or more units described in (a) and a total of 80 to 99.9 mol% of one or more units described in (b); Step 3. Extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 2 using an organic solvent, thereby obtaining a dispersion of hollow particles containing the organic solvent in the core, instead of the acrylic polymer; Step 4. A step to obtain hollow particles by drying the dispersion of hollow particles obtained in Step 3 to remove the organic solvent from inside the hollow particles. It has.

[0034] The method for producing a dispersion of hollow particles according to Embodiment A of the present invention may include the steps 1, 2, and 3 described above.

[0035] The acrylic polymer is preferably obtained by polymerizing acrylic acid esters and / or methacrylic acid esters in the presence of a cationic surfactant and an organic sulfur compound.

[0036] The particles containing the acrylic polymer (hereinafter referred to as the base particles) preferably have a weight-average molecular weight of less than 10,000 and a volume-average particle diameter of less than 500 nm. The composition of the base particles is not limited; for example, it may be a soft polymer such as butyl polyacrylate or butyl acrylate-butadiene copolymer, or a hard polymer such as butyl acrylate-styrene copolymer, butyl acrylate-acrylonitrile copolymer, butyl acrylate-styrene-acrylonitrile copolymer, or styrene-acrylonitrile copolymer. From the viewpoint of ease of removal in subsequent processes, a soft polymer is preferred.

[0037] Furthermore, the base particle composition is preferably a polymer using 50% by weight or more of butyl acrylate, and more preferably a polymer using 80% by weight or more of butyl acrylate.

[0038] The method for producing the base particles is not particularly limited, and known methods such as emulsion polymerization, micro-suspend polymerization, mini-emulsion polymerization, and aqueous dispersion polymerization can be used. Among these, production by emulsion polymerization is particularly preferred because it allows for easy control of particle size and is suitable for industrial production.

[0039] For example, it is preferable to use a surfactant (emulsifier) ​​similar to or the same as the cationic surfactant used in the synthesis of silicone-based compounds, as described later, during emulsion polymerization.

[0040] Radical polymerization initiators can be used for the polymerization of base particles. Specific examples of radical polymerization initiators include organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, and paramenthane hydroperoxide; inorganic peroxides such as potassium persulfate and ammonium persulfate; and azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile.

[0041] If the polymerization is carried out using a redox system such as ferrous sulfate-formaldehyde sulfoxylate sodium-ethylenediamine tetraacetyl acid 2Na salt, ferrous sulfate-glucose-sodium pyrophosphate, or ferrous sulfate-sodium pyrophosphate-sodium phosphate, polymerization can be completed efficiently even at low polymerization temperatures.

[0042] The base particles are preferably non-crosslinked polymers, considering that the removal of organic polymers (polymer components constituting the base particles) in a later stage may be carried out using organic solvents, and the weight-average molecular weight of the base particles is preferably low. Specifically, the weight-average molecular weight is preferably less than 10,000, and more preferably less than 7,000. To lower the weight-average molecular weight of the base particles, various means can be appropriately combined and selected, such as using a chain transfer agent, setting a high polymerization temperature, and using a large amount of initiator. As a chain transfer agent, t-dodecyl mercaptan, which is an organosulfur compound, is preferred. The amount of chain transfer agent used is preferably 1 to 30 parts by weight per 100 parts by weight of monomer.

[0043] While there are no specific lower limits on the weight-average molecular weight of the base particles, it is generally around 500 due to the difficulty of synthesis. The weight-average molecular weight can be measured, for example, by gel permeation chromatography (GPC) analysis (in polystyrene equivalent).

[0044] From the viewpoint of ensuring that hollow particles have a uniform porosity, a narrow particle size distribution of the base particles is preferable. Seed polymerization can be used to narrow the particle size distribution. Seed polymerization is a polymerization method in which seed particles are introduced, and then monomers of growth components are added and polymerization is carried out to grow the seed particles to a larger size.

[0045] Furthermore, in this embodiment A, it is preferable that the particle size of the base particles be smaller than the particle size of the hollow particles that are ultimately obtained.

[0046] Generally, the more surfactant (emulsifier) ​​used during emulsion polymerization, the smaller the average particle size of the resulting polymer can be.

[0047] The base particles used in this embodiment A may contain water-insoluble organic solvents such as toluene, benzene, xylene, and n-hexane, to facilitate the removal of the base particles in a later step, provided that the effects of the present invention are not impaired. The amount of organic solvent used is preferably 0 to 99% by weight, and more preferably 0 to 50% by weight, based on 100% by weight of the base particles. Using too much organic solvent may make it difficult to control the particle size distribution.

[0048] In this embodiment A, the particle size, particle size distribution, shell layer thickness, cavity size, and porosity of the hollow particles can be controlled by controlling the amount and ratio of base particles and silicone-based compounds used. The weight ratio of base particles to silicone-based compounds (base particles / silicone-based compound) is not necessarily limited, but is preferably 2 / 98 to 95 / 5, and more preferably 4 / 96 to 55 / 45. If the ratio is less than 2 / 98, the porosity of the final hollow particles may become too low. Conversely, if the ratio is greater than 95 / 5, the strength of the hollow particles may be insufficient, causing them to break during processing. Particles in which base particles are coated with a silicone-based compound are called core-shell particles.

[0049] In this embodiment A, the particle size of the core-shell particles and the ultimately obtained hollow particles is preferably less than 1000 nm. For optical and electronic material applications where transparency and thin-film formation are important, it is more preferable to have a particle size of less than 300 nm. The lower limit of the particle size is usually 10 nm or more.

[0050] To measure the porosity distribution of hollow particles, at least 10 particles are observed using TEM to measure their outer and inner diameters, and the average value of the porosity (the ratio of the volume of the internal cavity to the total volume of the particle) is calculated.

[0051] In this embodiment A, for example, core-shell particles coated with a silicone compound can be obtained by adding an emulsion, which is obtained by emulsifying a mixture of base particles and water containing a base catalyst at 5-120°C using a line mixer or homogenizer, all at once or continuously. Alternatively, the raw materials (a) and (b) can be emulsified separately and added separately. The emulsion can be added all at once or continuously. While this takes longer, continuous addition is preferable if stability and particle size distribution of the latex-like particles are important. If the base catalyst is added before the emulsion is added, and continuous addition is performed under conditions where hydrolysis and condensation reactions proceed immediately, the core-shell particles will grow significantly over time, resulting in a narrow particle size distribution similar to that of normal seed polymerization. Continuous addition for a relatively short period of time (less than 1 hour) can achieve both relatively good productivity and a narrow particle size distribution. As the cationic surfactant, any known cationic surfactant, such as amine salt type or quaternary ammonium salt type, can be used. Examples of cationic surfactants include alkylamine salts such as coconutamine acetate, laurylamine acetate, and stearylamine acetate; alkylbenzyldimethylammonium chlorides such as hexadecylbenzyldimethylammonium chloride and laurylbenzyldimethylammonium chloride; alkyltrimethylammonium chlorides such as lauryltrimethylammonium chloride, hexadecyltrimethylammonium chloride, stearyltrimethylammonium chloride, and cocoyltrimethylammonium chloride; and dialkyldimethyl chlorides such as didecyldimethylammonium and dialkyldimethylammonium. These cationic surfactants may be used individually or in combination of two or more. Among these cationic surfactants, lauryltrimethylammonium chloride is preferred.

[0052] Depending on the condensation reaction conditions of the silicone compound, the silicone compound may be formed not only on the surface of the base particles but also partially inside them. Since the silicone compound formed inside ultimately reduces the porosity of the hollow particles, its formation inside the particles must be prevented. This internal formation is presumed to be related to the rate of penetration, swelling, and condensation reaction of the silicone compound into the base particles. Therefore, it is preferable to advance the condensation reaction before sufficient penetration and swelling have occurred. Specifically, it is preferable to satisfy at least one of the following conditions (i) and (ii): (i) the continuous addition time of the silicone compound is 20 minutes or less, and (ii) the reaction temperature is 60°C or higher. Lowering the reaction temperature slows down the condensation reaction and tends to make it easier for the silicone compound to form inside the base particles. It is presumed that if the addition time of the silicone compound is extended, the silicone compound will penetrate and swell sufficiently, making it difficult to form a coating layer on the surface of the base particles. In this invention, the structure of the hollow particles can be controlled by optimizing the polymerization conditions of the silicone compound in this way.

[0053] In this embodiment A, cationic surfactants are preferably used, but other surfactants may be used in combination as needed. Other surfactants that can be used include anionic surfactants and nonionic surfactants. Specific examples of anionic surfactants include, for example, any known anionic surfactant such as fatty acid salt type, sulfate ester type, and sulfonate type. Examples include fatty acid soaps such as potassium oleate soap, potassium castor oil soap, semi-hardened beef tallow fatty acid sodium soap, semi-hardened beef tallow fatty acid potassium soap, and sodium stearate soap; alkyl sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkyl diphenyl ether disulfonates, alkylnaphthalene sulfonates, alkanesulfonates, and di(2-ethyl Examples include dialkyl sulfosuccinates such as hexyl) sulfosuccinate (sodium salt) and dioctyl sulfosuccinate (sodium salt); alkenyl succinates (dipotassium salt); alkyl phosphate esters; naphthalene sulfonic acid formalin condensates such as sodium salt of β-naphthalene sulfonic acid formalin condensate; polyoxyethylene alkylphenyl ether sulfates; polyoxyethylene alkyl ether sulfates such as polyoxyethylene lauryl ether sodium sulfate; polyoxyethylene alkyl sulfates; and polyoxyethylene styrene-phenyl ether sulfates. These anionic surfactants may be used individually or in combination of two or more.

[0054] Specific examples of nonionic surfactants include any known nonionic surfactants such as ester-type, ether-type, and ester-ether-type surfactants. Examples of such nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene myristyl ether, polyoxyethylene octyldodecyl ether, and polyoxyethylene tridecyl ether; polyoxyethylene alkylphenyl ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, and polyoxyethylene β-naphthyl ether; polyoxyalkylene alkyl ethers such as polyoxyethylene styrene-phenyl ether and polyoxyalkylene trialkyl ethers having 3 or more carbon atoms in the alkylene group; and sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monost Examples of nonionic surfactants include sorbitan fatty acid esters such as areates, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, and sorbitan trioleate; polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, and polyethylene glycol monooleate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, and polyoxyethylene sorbitan monooleate; polyoxyethylene alkylamines; glycerin fatty acid esters such as glycerol monostearate and glycerol monooleate; and oxyethylene-oxypropylene block polymers. These nonionic surfactants may be used individually or in combination of two or more. Among these nonionic surfactants, polyoxyethylene alkyl ethers are preferred.

[0055] Examples of base catalysts that can be used in this embodiment A include inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium phosphate, potassium phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate; amines such as ammonia, trimethylamine, triethylamine, diethylenetriamine, n-butylamine, dimethylaminoethanol, and triethanolamine; and quaternary ammonium salts such as tetramethylammonium hydroxide. Among these, inorganic bases, particularly disodium hydrogen phosphate, are preferred from the viewpoint of ease of removal from the product and the emulsification stability of organosiloxanes.

[0056] The conversion rate of the base particles and core-shell particles (the percentage of raw material monomers converted into polymer by polymerization reaction) can be calculated using the amount of solids obtained by drying each latex, as described in the Examples section below. A conversion rate of 60% or more is preferable, 70% or more is more preferable, and 75% or more is even preferable. If the conversion rate is less than 60%, a large amount of monomers that have not been converted into polymer will be present, which may result in a polymer with the intended composition not being obtained, and the effects of the present invention may not be fully realized.

[0057] In this embodiment A, if necessary, amino groups in the silicone compound can be used to graft polymerize another polymer after polymerization of core-shell particles or after isolation of the final hollow particles. Examples of polymers that can be graft polymerized include polyimides, polyamides, polyamideimides, and polyetherimides. After the amino groups in the silicone compound react with one of the polymer raw materials (e.g., dianhydrides, dicarboxylic acids or their activated products, carboxyl group-containing acid anhydrides, etc.) to form amide bonds, etc., the terminal acid anhydride groups, carboxyl groups and functional groups of their activated products derived from the molecular structure of the raw material further react with another polymer raw material (diamine, etc.) to increase the molecular weight. Alternatively, the molecular weight of the polymer can be increased in the liquid phase, etc., and then grafted by reacting it with amino groups on the particle surface. By applying the graft polymer to the hollow particles as described above, the dispersibility of the hollow particles in a matrix resin having a molecular structure similar to or the same as the graft polymer is improved, and it is expected that the heat resistance, optical properties, electrical properties, etc. of the hollow particles and the matrix resin can be further improved.

[0058] In this embodiment A, methods for removing the base particle portion from the core-shell particles include, for example, a method using an organic solvent or a method by combustion. The organic solvent used to remove the base particle portion from the core-shell particles is preferably one that dissolves the core base particle portion but does not dissolve the silicone-based compound that forms the shell. Specific examples include methyl ethyl ketone, toluene, benzene, xylene, n-hexane, and acetone. Furthermore, in this embodiment A, after removing the base particle portion, the core-shell particles can be further washed with an organic solvent. Specific examples of organic solvents that can be used for washing include methyl ethyl ketone, n-hexane, and methanol. A method for removing the base particle portion with an organic solvent includes, for example, heating the core-shell particles and the organic solvent, stirring and mixing to obtain solidified particles, allowing the solidified liquid to stand, and then filtering out the solidified particles.

[0059] The recovered solidified particles are dried at a temperature of 20 to 150°C for 1 minute to 48 hours, and under a vacuum environment if necessary, to obtain hollow particles.

[0060] [3. Resin composition] The resin composition according to this embodiment A contains the hollow particles and a matrix resin.

[0061] According to the above configuration, when the resin composition is used as a layer material for a circuit board, the dielectric constant can be lowered.

[0062] To obtain the resin composition of this embodiment A, hollow particles and a matrix resin can be blended using known methods. The blending method is not particularly limited. The hollow particles may be dispersed in a solvent or lubricant that is easily dispersed and compatible with the matrix resin, and this dispersion may be mixed with the matrix resin. Alternatively, the hollow particles in powder form may be added directly to the matrix resin and mixed. Furthermore, in this embodiment A, additives may be added to the resin composition as needed, as long as the effects of the present invention are achieved. Specific examples of solvents used include alcohols such as methanol, ethanol, propanol, butanol, and ethylene glycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ethers such as tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, and diethylene glycol dimethyl ether; hydroxyethers such as 2-methoxyethanol and 2-ethoxyethanol; phenols; aromatic hydrocarbons; chlorofluorocarbons (CFCs); and N,N-dimethylformamide and N-methyl-2-pyrrolidone.

[0063] The volume ratio of hollow particles to the total resin composition is preferably 0.1 to 50 vol%. In this case, the low dielectric constant of the resin composition, the strength of the layer material, and the adhesion are good. The lower limit of the volume ratio is more preferably 1 vol%, and even more preferably 5 vol%. The upper limit of the volume ratio is more preferably 40 vol%, and even more preferably 30 vol%.

[0064] As the matrix resin, any resin suitable as a material for the insulating layer of a circuit board can be used, but a thermosetting resin is preferred. Examples include epoxy resins, benzoxazine resins, bismaleimide resins, thermosetting polyimide resins, cyanate resins, bismaleimidotriazine resins, polyfunctional styrene compounds such as divinylbenzene, and modified polyphenylene ethers. Among the matrix resins mentioned above, epoxy resins are preferred because many of them are liquid and easy to incorporate hollow particles into, and because there is a wide variety of resins available, allowing for a broad selection of the necessary molecular structure according to the required physical properties. Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, brominated epoxy resins, hydrogenated epoxy resins, bisphenol S type epoxy resins, naphthalene type epoxy resins, phosphorus-containing epoxy resins, biphenyl type epoxy resins, trishydroxyphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, and dicyclopentadiene type epoxy resins. Alternatively, hydrogenated or halogenated versions of the epoxy resins can be used. These epoxy resins may be used individually or in combination of two or more types.

[0065] The matrix resin is preferably one that reacts with the amino groups of the hollow particles.

[0066] [4. Low dielectric materials] The low dielectric material according to this embodiment A is obtained from the resin composition. The low dielectric material is obtained, for example, by thermosetting the resin composition.

[0067] According to the above configuration, when a low-dielectric material is used as a layer material for a circuit board, the dielectric constant of the layer material is low. Therefore, the propagation speed of the circuit board does not decrease, and the transmission loss is small.

[0068] [5. Other uses] The hollow particles of the present invention can be used not only as insulating layers for circuit boards, but also in applications where general hollow particles are used. They can be used as materials with properties derived from their hollow structure (e.g., low refractive index, low dielectric constant, low specific gravity), as high-performance materials by encapsulating pigments, dyes, fragrances, pharmaceuticals, magnetic nanoparticles, etc., as nanoparticles, transparent materials, etc. by taking advantage of their small particle size, or as fillers, carriers, etc. by taking advantage of their uniform particle size and porosity. Specific examples of applications include anti-reflective coatings widely used in electrical products such as displays, optical products such as lenses, and building materials; inks used in general paints, electronic paper, polymerized toners, and displays; fillers for plastics, rubber, and paints; fillers for chromatography; wire grid polarizers used in liquid crystal displays and projectors; materials for diffusers in organic EL displays and lighting; electrical applications such as semiconductor nanoparticles, 3D photonic crystals, photoreceptors for electrophotography, transfer belts, and fixing belts; and magnetic nanoparticles. Applications include new cancer treatments using nanoparticles, drug delivery systems, gold colloids and their modifications, transdermal absorption formulations, and release control agents; use as modifiers for solvent-based pigments, materials for moisture-permeable fabrics, lightweight coated paper and cardboard, and sanitary materials such as antibacterial, breathable, and sustained-release porous films; separation membrane applications such as nanofiltration membranes, high-performance air filters, and anisotropic membranes with a dense internal layer; titanium dioxide as an environmental purification agent; and applications in cosmetics, light-regulating materials, adsorption materials, sound-insulating materials, heat-insulating materials, spacers, lightweighting agents, abrasives, shock absorption, vibration isolation, and vibration damping.

[0069] Embodiment A of the present invention may have the following configuration.

[0070] [1] (a)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 One or more units selected from the group of units, totaling 0.1 to 20 mol%, (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 One or more units selected from the group of units, totaling 80-99.9 mol%, Hollow particles having a layer made of a silicone-based compound containing [a specific compound].

[0071] [2] Hollow particles as described in [1], having a particle diameter of 10 to 1000 nm.

[0072] [3] A hollow particle according to [1] or [2], wherein the volume ratio of the internal space to the total volume is 10 to 70%.

[0073] A dispersion liquid obtained by dispersing any of the hollow particles described in [4], [1], to [3] in a solvent.

[0074] A resin composition comprising hollow particles as described in any of [5] [1] to [3] and at least a matrix resin.

[0075] [6] The resin composition according to [5], wherein the matrix resin is an epoxy resin.

[0076] A low dielectric material obtained from the resin composition described in [7], [5], or [6].

[0077] [8] Method for producing a dispersion of hollow particles comprising the following steps: Step 1: A step of polymerizing acrylic monomers in an aqueous medium in the presence of a surfactant containing a cationic surfactant to produce particles containing an acrylic polymer; Step 2. On the surface of the particles containing the acrylic polymer obtained in Step 1, (a)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 A step of producing multilayer particles by arranging a condensate of silanes, which are raw materials for one or more units selected from a group of units, wherein the condensate contains a total of 0.1 to 20 mol% of one or more units described in (a) and a total of 80 to 99.9 mol% of one or more units described in (b); Step 3. A step to obtain a dispersion of hollow particles containing an organic solvent in the core, by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 2 using an organic solvent.

[0078] A method for producing hollow particles, comprising the step of drying the dispersion of hollow particles obtained by the method for producing a dispersion of hollow particles described in [9] and [8] to remove the organic solvent inside the hollow particles and obtain hollow particles.

[0079] [Embodiment B] [1. Method for producing hollow particles] The method for producing hollow particles in Embodiment B of the present invention comprises the following steps 1 to 3: Step 1. In the presence of a cationic surfactant, (1)R is applied to the surface of the particles containing the acrylic polymer. 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 A process for producing multilayer particles by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof; Step 2. A step to obtain hollow particles by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 1 using an organic solvent; Step 3. R constituting the hollow particles obtained in Step 2 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 A hydroxyl group encapsulation step that generates one or more units selected from a group consisting of units, wherein the sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3. A process in which the amount is 0.01 mmol / g or more.

[0080] In the method for producing hollow particles of Embodiment B of the present invention, step 2 may be a step in which the acrylic polymer inside the multilayer particles obtained in step 1 is extracted and removed with an organic solvent, and then dried to obtain hollow particles.

[0081] The following describes each step.

[0082] [1-1. Process 1] Step 1 involves applying (1)R to the surface of particles containing an acrylic polymer in the presence of a cationic surfactant. 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 This process involves arranging silanes, which are raw materials for one or more units selected from a group of units, with condensates thereof to produce multilayer particles.

[0083] Of the constituent units of (1) and (3) above, R 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 The unit contains a silanol group. In this invention, by encapsulating the silanol group in step 3 described later, it is possible to realize hollow particles that can be used as materials for electrical materials having very low Dk and Df.

[0084] The particles containing the acrylic polymer may be formed from organic polymer particles (A), from an organic solvent (B), or from both organic polymer particles (A) and an organic solvent (B).

[0085] When the particles containing the acrylic polymer are formed from organic polymer particles (A) and an organic solvent (B), the weight ratio of organic polymer particles (A) to organic solvent (B) (organic polymer particles (A) / organic solvent (B)) is preferably in the range of 99 / 1 to 1 / 99.

[0086] Examples of polymers constituting the organic polymer particles (A) include the soft polymer and the hard polymer. From the viewpoint of polymerizability and / or solvent solubility, among these, butyl polyacrylate, butyl acrylate-butadiene copolymer, butyl acrylate-styrene copolymer, butyl acrylate-acrylonitrile copolymer, and butyl acrylate-styrene-acrylonitrile copolymer are preferred, and butyl polyacrylate is particularly preferred.

[0087] The organic solvent (B) can be any substance that is insoluble in water and can form particles with an emulsifier, such as toluene, benzene, xylene, and n-hexane. Of course, the organic solvent is not limited to these.

[0088] The method for producing the organic polymer particles (A) is not particularly limited, and known methods such as emulsion polymerization, micro-suspend polymerization, mini-emulsion polymerization, and aqueous dispersion polymerization can be used. Among these, it is preferable to produce the organic polymer particles (A) by emulsion polymerization because it allows for easy control of particle size and is suitable for industrial production.

[0089] A radical polymerization initiator may be used for the polymerization of the organic polymer constituting the organic polymer particles (A). Examples of radical polymerization initiators include those exemplified in Embodiment A. It is preferable to carry out the polymerization using a redox system, for example, ferrous sulfate-formaldehyde sulfoxylate sodium-ethylenediamine tetraacetyl acid 2Na salt, ferrous sulfate-glucose-sodium pyrophosphate, or ferrous sulfate-sodium pyrophosphate-sodium phosphate, because polymerization can be completed efficiently even at low polymerization temperatures.

[0090] The organic polymer constituting the organic polymer particles (A) is preferably a non-crosslinked polymer and / or a polymer with a low molecular weight, considering the subsequent step 2 (a step in which the acrylic polymer inside the multilayer particles obtained in step 1 (for example, the organic polymer constituting the organic polymer particles (A)) is extracted and removed using an organic solvent). The weight-average molecular weight of the organic polymer constituting the organic polymer particles (A) is preferably less than 30,000, and more preferably less than 10,000.

[0091] Methods for lowering the weight-average molecular weight of the organic polymer constituting the organic polymer particles (A) include, for example, at least one method selected from the group consisting of using a chain transfer agent, setting a high polymerization temperature, and using a large amount of initiator. Examples of chain transfer agents include t-dodecyl mercaptan and n-dodecyl mercaptan. The lower limit of the weight-average molecular weight of the organic polymer constituting the organic polymer particles (A) is not particularly limited, but from the standpoint of the difficulty of synthesis, it is generally around 2000. The weight-average molecular weight can be measured, for example, by analysis by gel permeation chromatography (GPC) (in polystyrene equivalent).

[0092] To narrow the particle size distribution of the aforementioned organic polymer particles (A), the organic polymer particles (A) can also be manufactured using a seed polymerization method. The volume-average particle size of the particles (e.g., latex-state organic polymer particles (A), core-shell particles) can be determined by light scattering. The volume-average particle size and particle size distribution can be measured, for example, using the EX-150 manufactured by MIOCROTRAC.

[0093] In step 1, for example, the volume ratio of the acrylic polymer-containing particles (cores) to the total volume of the multilayer particles can be adjusted by controlling the ratio of the weight of the acrylic polymer-containing particles to the weight of the condensate placed on the surface of the particles. The volume ratio of the acrylic polymer-containing particles (cores) to the total volume of the multilayer particles is preferably 10 to 70%, and more preferably 15 to 50%.

[0094] In step 1, for example, the volume-average particle diameter of the multilayer particles can be adjusted by controlling the weight of the acrylic polymer-containing particles and the weight of the condensate arranged on the surface of the particles (or by controlling the ratio of these weights). The volume-average particle diameter of the multilayer particles is preferably 10 nm to 1000 nm, and more preferably 20 nm to 500 nm.

[0095] In step 1, multilayer particles are produced in the presence of a cationic surfactant. Any known cationic surfactant, such as an amine salt type or a quaternary ammonium salt type, can be used as the cationic surfactant, but examples of such cationic surfactants include those exemplified in Embodiment A. Among these cationic surfactants, lauryltrimethylammonium chloride is preferred.

[0096] In step 1, multilayer particles may be produced in the presence of a nonionic surfactant. That is, in step 1, a cationic surfactant may be used as the surfactant, a nonionic surfactant may be used, or both a cationic surfactant and a nonionic surfactant may be used. As the nonionic surfactant, any known nonionic surfactant such as ester type, ether type, or ester-ether type can be used, but examples of such nonionic surfactants include the nonionic surfactant exemplified in Embodiment A. Among these nonionic surfactants, polyoxyethylene alkyl ether is preferred.

[0097] In step 1, multilayer particles may be produced in the presence of a basic catalyst. Examples of such basic catalysts include inorganic basic catalysts (e.g., sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate), amines (e.g., trimethylamine, triethylamine, pyridine, N,N-dimethylaminopyridine), and quaternary ammonium salts. Among these, disodium hydrogen phosphate is particularly preferred from the viewpoint of excellent emulsification stability of organosiloxanes.

[0098] In step 1, the polymerization reaction may proceed while heating. The heating temperature is not limited, but is preferably 5 to 120°C, and more preferably 20 to 80°C. With this configuration, an appropriate polymerization rate can be achieved.

[0099] In step 1, (1)R is applied to the surface of the particles containing the acrylic polymer. 1 SiO 3 / 2 Unit, R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2Multilayer particles (for example, two-layer particles having a core particle containing an acrylic polymer and a condensate covering the surface of the core particle) are produced by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof.

[0100] (1)R 1 SiO 3 / 2 Unit, R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 In the unit, R1 represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0101] R1SiO 3 / 2 Examples of raw materials for the unit include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane, and one or more of these can be used in combination as appropriate.

[0102] (3)R 3 SiO 3 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 R in the unit 3 This represents an alkyl group having 1 to 4 carbon atoms that does not contain an amino group. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0103] R 3 SiO 3 / 2 Examples of raw materials for the units include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane, and one or more of these can be used in combination as appropriate.

[0104] More specifically, in Step 1, an emulsifier (cationic surfactant and / or nonionic surfactant), and (1) R 1 SiO 3 / 2 units, R 1 Si(OH)O 2 / 2 units, and R 1 Si(OH)2O 1 / 2 units, one or more silanes as raw materials for units selected from the group consisting of, and (3) R 3 SiO 3 / 2 units, R 3 Si(OH)O 2 / 2 units, and R 3 Si(OH)2O 1 / 2 units, one or more silanes as raw materials for units selected from the group consisting of, and water, an emulsifier emulsified by a line mixer or a homogenizer, may be added batchwise or continuously to produce multilayer particles.

[0105] The addition of the emulsifier may be carried out batchwise or continuously. If the emulsifier is added continuously, it is preferable because it is easy to produce multilayer particles with good stability and easy to adjust the particle size distribution of the multilayer particles.

[0106] If a basic catalyst is added to the organic polymer particles (A) and / or the organic solvent (B) before adding the emulsifier, the conditions for the hydrolysis and condensation reactions to proceed immediately after the addition of the emulsifier can be adjusted. Under these conditions, if the emulsifier is added continuously to the organic polymer particles (A) and / or the organic solvent (B), the multilayer particles grow large over time, and multilayer particles with a narrow particle size distribution can be obtained, like normal seed polymerization. If the emulsifier is added continuously for a short time (for example, 30 minutes to 1 hour), multilayer particles can be produced with good productivity and multilayer particles with a narrow particle size distribution can be produced.

[0107] 〔1-2. Step 2〕 Step 2 is a step of obtaining hollow particles by extracting and removing the acrylic polymer inside the multilayer particles obtained in Step 1 with an organic solvent. When the inside of the multilayer particles obtained in Step 1 is formed by the organic polymer particles (A) and / or the organic solvent (B), Step 2 can be a step of obtaining hollow particles by extracting and removing the organic polymer particles (A) and / or the organic solvent (B) inside the multilayer particles obtained in Step 1 with an organic solvent.

[0108] As another form of Step 2, Step 2 may be a step of obtaining hollow particles by removing the acrylic polymer (or the organic polymer particles (A) and / or the organic solvent (B)) inside the multilayer particles obtained in Step 1 by combustion.

[0109] As the organic solvent, one that dissolves the acrylic polymer (or the organic polymer particles (A) and / or the organic solvent (B)) inside the multilayer particles (core) and does not dissolve the silicone-based compound on the surface (shell) of the multilayer particles can be used. Examples of the organic solvent include acetone, toluene, methyl ethyl ketone, benzene, xylene, and n-hexane. From the viewpoint of relatively low boiling point and easy removal, among these organic solvents, acetone, methyl ethyl ketone, and n-hexane are preferred.

[0110] Step 2 may include a step of drying the particles obtained in Step 2 to obtain hollow particles. Step 2 may be a step of obtaining hollow particles by extracting and removing the acrylic polymer inside the multilayer particles obtained in Step 1 with an organic solvent and then drying. More specifically, Step 2 may be a step of obtaining hollow particles by drying the particles obtained by extracting and removing the acrylic polymer inside the multilayer particles obtained in Step 1 with an organic solvent.

[0111] The method for drying the particles obtained in step 2 is not limited. For example, the particles obtained in step 2 can be dried in an oven at a temperature of 100°C to 150°C for 3 to 10 hours. Of course, the temperature and / or time can be set appropriately based on the amount and size of the particles.

[0112] [1-3. Process 3] Step 3 involves R, which constitutes the hollow particles obtained in Step 2. 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 This is a hydroxyl group encapsulation step that generates one or more units selected from a group of units. In step 3, the sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3 The amount is 0.01 mmol / g or more.

[0113] In other words, in step 3, the final product, hollow particles, is obtained by sealing at least some of the silanol groups contained in the shells of the hollow particles (unsealed particles) obtained in step 2 with a sealing agent. With this method, if a suitable sealing agent is selected, it is possible to selectively seal only the silanols, and the possibility of destroying other functional groups is low.

[0114] The encapsulant is not limited to, but examples include trimethylsilyl imidazole (N-trimethylsilyl imidazole), hexamethylene disilazane, trimethylchlorosilane, and N,O-trimethylsilylacetamide. These encapsulants may be used individually or in any combination of two or more.

[0115] (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Units, and R 1 Si(OSi(R 2 )3)2O 1 / 2 Units, and (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units, and R 3 Si(OSi(R 2 )3)2O 1 / 2 Each R2 in the unit represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0116] In step 3, the sum of (1) and (2) is 0.1 to 20 mol%, preferably 1 to 15 mol%, and more preferably 1 to 10 mol%. With this configuration, further reduction of dielectric constant (low dielectric constant and low dielectric loss tangent) of the electrical material obtained from the resin composition containing hollow particles can be achieved, and the reaction of the amino groups with the resin can also contribute to the dispersibility of the hollow particles in the resin composition.

[0117] In step 3, the sum of (3) and (4) is 80 to 99.9 mol%, preferably 85 to 99.0 mol%, and more preferably 90 to 99.0 mol%. With this configuration, further reduction of dielectric constant (low dielectric constant and low dielectric loss tangent) of the electrical material obtained from the resin composition containing hollow particles can be achieved.

[0118] In step 3, the Si-OSi(R 2 The amount of )3 is 0.01 mmol / g or more, preferably 0.15 mmol / g or more, and more preferably 0.25 mmol / g or more. With this configuration, further reduction of dielectric constant (reduction of dielectric loss tangent) can be achieved in the electrical material obtained from the resin composition containing hollow particles.

[0119] [2. Hollow particles] Embodiment B of the present invention is a hollow particle having a layer made of a silicone compound containing the following constituent units (1) to (4), The sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3. The amount is 0.01 mmol / g or more, and it is a hollow particle: (1)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 One or more units selected from a group of units; (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 One or more units selected from a group of units; (3)R 3SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 One or more units selected from a group of units; (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 One or more units selected from a group of units.

[0120] In the hollow particles of Embodiment B of the present invention, the sum of (1) and (2) is 0.1 to 20 mol%, preferably 1 to 15 mol%, and more preferably 1 to 10 mol%. With this configuration, further reduction of dielectric constant (reduction of dielectric loss tangent) of the electrical material obtained from the resin composition containing the hollow particles can be achieved, and the reaction of the amino group with the resin can also contribute to the dispersibility of the hollow particles in the resin composition.

[0121] In the hollow particles of Embodiment B of the present invention, the sum of (3) and (4) is 80 to 99.9 mol%, preferably 85 to 99.0 mol%, and more preferably 90 to 99.0 mol%. With this configuration, further reduction of dielectric constant (reduction of dielectric loss tangent) of the electrical material obtained from the resin composition containing hollow particles can be achieved.

[0122] In the hollow particle of Embodiment B of the present invention, the Si-OSi(R 2 The amount of )3 is 0.01 mmol / g or more, preferably 0.15 mmol / g or more, and more preferably 0.25 mmol / g or more. With this configuration, further reduction of dielectric constant (reduction of dielectric loss tangent) can be achieved in the electrical material obtained from the resin composition containing hollow particles.

[0123] (1)R 1SiO 3 / 2 Unit, R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 In the unit, R1 represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0124] R1SiO 3 / 2 Examples of raw materials for the unit include 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane, and one or more of these can be used in combination as appropriate.

[0125] (3)R 3 SiO 3 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 R in the unit 3 This represents an alkyl group having 1 to 4 carbon atoms that does not contain an amino group. Examples of such alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0126] R 3 SiO 3 / 2 Examples of raw materials for the units include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and ethyltripropoxysilane, and one or more of these can be used in combination as appropriate.

[0127] (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Units, and R 1 Si(OSi(R 2 )3)2O 1 / 2 Units, and (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units, and R 3Si(OSi(R 2 )3)2O 1 / 2 In the unit, each of R2 is the same or different and represents an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.

[0128] The hollow particles of Embodiment B of the present invention preferably have a remaining Si-OH (silanol group) amount of 0.35 mmol / g or less, more preferably 0.30 mmol / g or less, still more preferably 0.27 mmol / g or less, and most preferably 0.20 mmol / g or less. With such a configuration, further reduction in dielectric constant (reduction in dielectric constant and dielectric loss tangent) of an electrical material obtained from a resin composition containing the hollow particles can be achieved.

[0129] The hollow particles of Embodiment B of the present invention preferably have a particle diameter of 10 nm to 1000 nm, more preferably 20 nm to 500 nm. With such a configuration, not only can the hollow particles of Embodiment B of the present invention be easily synthesized, but also the flatness of an electrical material obtained from a resin composition containing the hollow particles and a matrix resin can be improved. In the present invention, the particle diameter of the hollow particles can be determined as the outer diameter of the particles in a TEM image obtained first, as described in the examples below. More specifically, the outer diameter can be measured for each of 10 or more (for example, 15 to 20) particles, more preferably 100 or more particles, and still more preferably 1000 or more particles, and the particle diameter can be determined as the average value of the measured values.

[0130] The hollow particles of Embodiment B of the present invention preferably have a volume ratio of the internal space to the total volume of 10 to 70%, more preferably 15 to 50%. With such a configuration, not only can reduction in dielectric constant (reduction in dielectric constant and dielectric loss tangent) of an electrical material obtained from a resin composition containing the hollow particles be achieved, but also the strength of the hollow particles can be increased.

[0131] 〔3. Resin Composition and Low-Dielectric Material〕 The resin composition of Embodiment B of the present invention contains hollow particles of Embodiment B of the present invention and a matrix resin.

[0132] The matrix resin is not limited to polyimide resin, and examples include polyimide resin, polyimide resin precursor, silicon-based resin, and fluororesin, and one or more of these can be used in combination as appropriate. From the viewpoint of obtaining the advantageous effect of providing an interlayer insulating film with excellent flatness and productivity, polyimide resin and polyimide resin precursor are preferred among these matrix resins.

[0133] Polyimide resins are a general term for polymers that contain imide bonds within their repeating units, and usually refer to aromatic polyimides in which aromatic compounds are directly linked by imide bonds.

[0134] Aromatic polyimides have a rigid and robust molecular structure because aromatic molecules form a conjugated structure via imide bonds. Due to the strong intermolecular forces of the imide bonds, aromatic polyimides possess the highest levels of thermal, mechanical, and chemical properties among all polymers.

[0135] A common method for producing aromatic polyimides is a two-step process, as follows: Equimolar polymerization of tetracarboxylic acid dianhydride and a diamine is performed to obtain polyamic acid (polyamic acid), a precursor of polyimide. This precursor is then subjected to heat treatment at 200°C or higher, or to dehydration and cyclization (imidation) using a catalyst to obtain polyimide. For example, amine compounds can be used as the catalyst. A carboxylic acid anhydride can also be used in combination with the catalyst-based dehydration and cyclization (imidation) process to rapidly remove water generated during imidation.

[0136] Modified compounds of polyimide resins can also be used as polyimide resins. For example, the melt flowability and toughness of the polyimide resin can be improved by introducing easily rotatable linking groups (e.g., -O-, -S-, CO-) between the benzene rings that make up the main chain. In addition, the melt flowability of the polyimide resin can be improved by introducing stable and bulky functional groups (e.g., phenyl groups, methyl groups) as side chains of the polyimide resin.

[0137] The resin composition of Embodiment B of the present invention can be obtained by known methods. To obtain the resin composition of Embodiment B of the present invention, for example, the hollow particles of Embodiment B of the present invention and the matrix resin can be blended by known methods. The blending method is not limited, but for example, a preferred method is to disperse the hollow particles of Embodiment B of the present invention in a solvent that is compatible with the matrix resin and in which the hollow particles of Embodiment B of the present invention are easily finely dispersed, and then mix this dispersion with the matrix resin.

[0138] Examples of the aforementioned solvents include alcohols (e.g., methanol, ethanol, propanol, ethylene glycol), ketones (e.g., methyl ethyl ketone, methyl isobutyl ketone), esters, phenols, aromatic hydrocarbons, chlorofluorocarbons (CFCs), N-methylpyrrolidone, and dimethylformamide. Of these, N-methylpyrrolidone and dimethylformamide are preferred from the viewpoint of compatibility with the matrix resin. Additives may be added to the resin composition of Embodiment B of the present invention as needed.

[0139] The weight ratio of the dispersion containing the hollow particles of Embodiment B of the present invention to the matrix resin is preferably in the range of 99 / 1 to 1 / 99, and more preferably in the range of 5 / 95 to 80 / 20. With this configuration, the strength of the dielectric material (e.g., a film-like dielectric material) obtained from the resin composition of Embodiment B of the present invention can be increased, and the dielectric strength of the dielectric material can be reduced.

[0140] The resin composition of Embodiment B of the present invention can be molded into a desired shape (for example, a sheet of a desired thickness).

[0141] The low dielectric material of Embodiment B of the present invention is obtained from the resin composition of Embodiment B of the present invention. For example, the low dielectric material of Embodiment B of the present invention can be obtained by heating and curing the resin composition of Embodiment B of the present invention. The low dielectric material of Embodiment B of the present invention may consist of the resin composition of Embodiment B of the present invention, or it may contain the resin composition of Embodiment B of the present invention and components other than the resin composition of Embodiment B of the present invention.

[0142] The low dielectric material of Embodiment B of the present invention can be molded into a desired shape (for example, a sheet of a desired thickness).

[0143] The low dielectric material of Embodiment B of the present invention may, for example, have a dielectric constant (Dk) (10 GHz / 50% RH) of 3.00 or less, 2.90 or less, 2.80 or less, 2.70 or less, 2.60, 2.50 or less, 2.40 or less, 2.30 or less, 2.20 or less, 2.10 or less, or 2.00 or less. The lower limit of the dielectric constant (Dk) is not limited and may be, for example, 0.01 or more, 0.05 or more, or 0.10 or more.

[0144] The low dielectric material of Embodiment B of the present invention may, for example, have a dielectric loss tangent (Df) (10 GHz / 50% RH) of 0.0040 or less, 0.0039 or less, 0.0038 or less, 0.0037 or less, 0.0036 or less, 0.0035 or less, 0.0034 or less, 0.0033 or less, 0.0032 or less, 0.0031 or less, 0.0030 or less, 0.0029 or less, 0.0028 or less, 0.0027 or less, 0.0026 or less, or 0.0025 or less. The lower limit of the dielectric loss tangent (Df) is not limited and may be, for example, 0.0001 or more, 0.0005 or more, or 0.0010 or more.

[0145] Embodiment B of the present invention may also have the following configuration.

[0146] [1] Hollow particles having a layer made of a silicone compound containing the following constituent units (1) to (4), The sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3 Hollow particles with a concentration of 0.01 mmol / g or more: (1)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 One or more units selected from a group of units; (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 unit One or more units selected from the group consisting of the following; (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 One or more units selected from a group of units; (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 One or more units selected from a group of units.

[0147] [2] The hollow particle described in [1], wherein the residual Si-OH content is 0.35 mmol / g or less.

[0148] [3] Hollow particles as described in [1] or [2], having a particle diameter of 10 to 1000 nm.

[0149] [4] A hollow particle according to any of [1] to [3], wherein the volume ratio of the internal space to the total volume is 10 to 70%.

[0150] A resin composition containing hollow particles as described in any of [5][1] to [4] and a matrix resin.

[0151] [6] The resin composition according to [5], wherein the matrix resin is a polyimide resin.

[0152] A low dielectric material obtained from the resin composition described in [7], [5], or [6].

[0153] [8] A method for producing hollow particles comprising the following steps: Step 1. In the presence of a cationic surfactant, (1)R is applied to the surface of the particles containing the acrylic polymer. 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 A process for producing multilayer particles by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof; Step 2. A step to obtain hollow particles by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 1 using an organic solvent; Step 3. R constituting the hollow particles obtained in Step 2 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 Unit, (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 A hydroxyl group encapsulation step that generates one or more units selected from a group consisting of units, The sum of (1) and (2) above is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3. A process in which the amount is 0.01 mmol / g or more.

[0154] [9] The method for producing hollow particles according to [8], wherein step 2 is a step of extracting and removing the acrylic polymer inside the multilayer particles obtained in step 1 with an organic solvent, and then drying them to obtain hollow particles.

[0155] [others] One embodiment of the present invention may have the following configuration:

[0156] [1](a)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O2 / 2 Units, and R 1 Si(OH)2O 1 / 2 One or more units selected from the group of units, totaling 0.1 to 20 mol%, (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 One or more units selected from the group of units, totaling 80-99.9 mol%, Hollow particles having a layer made of a silicone-based compound containing [a specific compound].

[0157] [2] Hollow particles having a layer made of a silicone compound containing the following constituent units (1) to (4), The sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3 Hollow particles with a concentration of 0.01 mmol / g or more: (1)R 1 SiO 3 / 2 Unit (in the formula, R) 1 This represents an alkyl group with 1 to 4 carbon atoms that has an amino group. The same applies below.) R 1 Si(OH)O 2 / 2 Units and R 1 Si(OH)2O 1 / 2 unit One or more units selected from the group consisting of the following; (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 These represent alkyl groups with 1 to 4 carbon atoms, which may be the same or different. (The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 unit One or more units selected from the group consisting of the following; (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 This represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below.) R 3 Si(OH)O 2 / 2 Units and R 3 Si(OH)2O 1 / 2 unit One or more units selected from the group consisting of the following; (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2 )3)2O 1 / 2 unit One or more units selected from the group consisting of the following.

[0158] [3] The hollow particle described in [2], wherein the residual Si-OH content is 0.35 mmol / g or less.

[0159] [4] A hollow particle as described in any of [1] to [3], having a particle diameter of 10 to 1000 nm.

[0160] [5] A hollow particle according to any of [1] to [4], wherein the volume ratio of the internal space to the total volume is 10 to 70%.

[0161] A dispersion liquid obtained by dispersing hollow particles described in any of [6][1] to [5] in a solvent.

[0162] A resin composition containing hollow particles as described in any of [7][1] to [6] and a matrix resin.

[0163] [8] The resin composition according to [7], wherein the matrix resin is an epoxy resin or a polyimide resin.

[0164] A low dielectric material obtained from the resin composition described in [9], [7], or [8].

[0165]

[10] A method for producing a dispersion of hollow particles comprising the following steps: Step 1: A step of polymerizing acrylic monomers in an aqueous medium in the presence of a surfactant containing a cationic surfactant to produce particles containing an acrylic polymer; Step 2. On the surface of the particles containing the acrylic polymer obtained in Step 1, (a)R 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (b)R 2 SiO 3 / 2 Unit (in the formula, R) 2 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 2 Si(OH)O 2 / 2 Units, and R 2 Si(OH)2O 1 / 2 A step of producing multilayer particles by arranging a condensate of silanes, which are raw materials for one or more units selected from a group of units, wherein the condensate contains a total of 0.1 to 20 mol% of one or more units described in (a) and a total of 80 to 99.9 mol% of one or more units described in (b); Step 3. A step to obtain a dispersion of hollow particles containing an organic solvent in the core, by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 2 using an organic solvent.

[0166] A method for producing hollow particles, comprising the step of drying the dispersion of hollow particles obtained by the method for producing a dispersion of hollow particles described in

[11]

[10] to remove the organic solvent inside the hollow particles and obtain hollow particles.

[0167]

[12] A method for producing hollow particles comprising the following steps: Step 1. In the presence of a cationic surfactant, (1)R is applied to the surface of the particles containing the acrylic polymer. 1 SiO 3 / 2 Unit (in the formula, R) 1 ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies below. ), R 1 Si(OH)O 2 / 2 Units, and R 1 Si(OH)2O 1 / 2 Silanes that serve as raw materials for one or more units selected from a group of units, and (3)R 3 SiO 3 / 2 Unit (in the formula, R) 3 ) represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies below. ), R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 A process for producing multilayer particles by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof; Step 2. A step to obtain hollow particles by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 1 using an organic solvent; Step 3. R constituting the hollow particles obtained in Step 2 1 Si(OH)O 2 / 2 Unit, R 1 Si(OH)2O 1 / 2 Unit, R 3 Si(OH)O 2 / 2 Units, and R 3 Si(OH)2O 1 / 2 (2)R 1 Si(OSi(R 2 )3)O 2 / 2 Unit (in the formula, R) 2 Each of these represents an alkyl group having 1 to 4 carbon atoms, either identical or different. The same applies hereinafter.) and R 1 Si(OSi(R 2 )3)2O 1 / 2 Unit, (4)R 3 Si(OSi(R 2 )3)O 2 / 2 Units and R 3 Si(OSi(R 2)3)2O 1 / 2 A hydroxyl group encapsulation step that generates one or more units selected from a group consisting of units, The sum of (1) and (2) above is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R 2 )3. A process in which the amount is 0.01 mmol / g or more.

[0168]

[13] The method for producing hollow particles according to

[12] , wherein step 2 is a step of extracting and removing the acrylic polymer inside the multilayer particles obtained in step 1 with an organic solvent, and then drying them to obtain hollow particles. [Examples]

[0169] [Example A] Embodiment A of the present invention will be described in more detail below with reference to Example A and Comparative Example A. The present invention is not limited to the following embodiments. Embodiment A of the present invention can be modified as appropriate to conform to the spirit of the above or below, and all such modifications are included within the technical scope of the present invention.

[0170] The measurements in Example A and Comparative Example A were carried out as follows.

[0171] [Conversion rate] The conversion rates of the base particles, core-shell particles, and silicone solid particles were calculated using the amount of solids obtained by drying each latex.

[0172] [Volume-average particle diameter] The volume-average particle size (nm) of core-shell particles was measured in latex form. A Nanotrac wave EX-150 from MIOCROTRAC was used as the measurement device. The measurement time was 120 seconds.

[0173] [Weight-average molecular weight of organic polymers] The weight-average molecular weight of organic polymers was measured by the following GPC analysis. System: Tosoh Corporation "HLC-82201", Columns: Tosoh Corporation "TSKgel SuperH5000", "TSKgel SuperH4000", "TSKgel SuperH3000", "TSKgel SuperH2000", Solvent: THF. The weight-average molecular weight was determined in polystyrene equivalent.

[0174] [Measurement of the ratio of the average particle diameter to the average volume of the internal space of hollow particles] The average particle diameter of hollow particles and the volume ratio of the internal space to the total volume were determined using a transmission electron microscope (TEM). Observation samples were obtained by dropping a solution containing dispersed hollow particles onto a grid mesh with a support film and drying to remove the solvent, or by dispersing hollow particles in TEM embedding resin, photocuring, and then cutting ultrathin sections with an ultramicrotome. The average particle diameter was defined as the average of the outer diameters of 10 particles in the observation photographs. Furthermore, the outer diameter and inner diameter (hollow diameter) were measured, and the average volume ratio was calculated according to the following formula: Volume ratio (%) = (Inner diameter / Outer diameter) 3 ×100.

[0175] [Amount of hollow particles added to epoxy resin composition] The amount (vol%) of hollow particles added to the epoxy resin composition was calculated according to the following formula, based on the weight of each component in the epoxy resin composition, the density of the epoxy resin, the density of the silicone compound constituting the hollow particles, the density of air, and the average volume ratio of the internal space of the hollow particles determined above. The density of each component was: epoxy resin: 1.17 g / cm³. 3 Silicone-based compounds: 1.26 g / cm³ 3 Air density: 0.001 g / cm³ 3 That's what I decided. Volume of epoxy resin = Weight of epoxy resin / Density of epoxy resin • Density of hollow particles = Density of air × (Average volume ratio / 100) + Density of silicone compound × (1 - Average volume ratio / 100) Volume of a hollow particle = Weight of the hollow particle / Density of the hollow particle • Amount of hollow particles added to the epoxy resin composition (vol%) = Volume of hollow particles / (Volume of epoxy resin + Volume of hollow particles) × 100.

[0176] [Confirmation of whether or not the hollow particles in the epoxy resin penetrate the interior and the dispersibility of the hollow particles] The presence or absence of epoxy resin penetration into the hollow particles and the dispersibility of the particles in the cured epoxy resin were confirmed using a transmission electron microscope (TEM). Small pieces of the cured epoxy resin containing hollow particles were embedded in TEM embedding resin, and ultrathin sections were cut using an ultramicrotome to be used as observation samples. RuO4 was used to stain the samples. The presence or absence of epoxy resin penetration was determined by comparing the contrast between the core of the hollow particles and the background (epoxy resin). Furthermore, the dispersibility was determined by the presence or absence of aggregates of hollow particles.

[0177] [Evaluation of dielectric properties of layered material (cured product)] For epoxy resin cured products with added hollow particles, the dielectric constant and dielectric loss tangent were measured overnight under controlled temperature and humidity conditions of 22-24°C and 45-55% relative humidity. This was done using a network analyzer E5071C (Keysight Technologies) connected to a cavity resonator dielectric constant measuring device (EM Lab Co., Ltd.) at a frequency of 10 GHz, 22-24°C, and 45-55% relative humidity.

[0178] (Example A1) In a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 60 parts by weight of pure water (total amount of water including various dilution waters), 2.2 parts by weight of polyoxyethylene alkyl ether, and 2.2 parts by weight of lauryltrimethylammonium chloride were added, and the mixture was heated to 50°C while stirring under a nitrogen stream. After 30 minutes, 0.00096 parts by weight of ethylenediamine tetraacetyl acid disodium salt / ferrous sulfate heptahydrate chelate complex and 0.38 parts by weight of sodium formaldehyde sulfoxylate were added, and then a mixture of 5.0 parts by weight of butyl acrylate, 1.0 part by weight of t-dodecyl mercaptan, and 0.0080 parts by weight of cumene hydroperoxide was added dropwise at a constant rate over 9 minutes. Ten minutes after the end of the dropwise addition, 0.0020 parts by weight of cumene hydroperoxide was added, and the mixture was polymerized for 90 minutes.

[0179] Next, 240 parts by weight of pure water warmed to 50°C (total amount of water including various dilution waters) and 0.019 parts by weight of ethylenediamine tetraacetyl acid 2Na salt / ferrous sulfate heptahydrate chelate complex were added and the mixture was stirred for 10 minutes. Then, a mixture of 95 parts by weight of butyl acrylate, 19 parts by weight of t-dodecyl mercaptan, and 0.15 parts by weight of cumene hydroperoxide was added dropwise at a constant rate over 190 minutes. At 40, 80, 120, and 160 minutes after the start of the dropwise addition of the mixture, a mixture of 0.15 parts by weight of polyoxyethylene alkyl ether and 0.15 parts by weight of lauryltrimethylammonium chloride were added, respectively. Ten minutes after the completion of the 190 minutes of dropwise addition, 0.048 parts by weight of cumene hydroperoxide was added, and post-polymerization was carried out for 90 minutes to obtain an organic polymer latex (Lx-1) that would serve as the base particle. The conversion rate calculated from the solid content of the obtained Lx-1 was 97%. The weight-average molecular weight of this organic polymer was 3900.

[0180] In a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 500 parts by weight of pure water (total amount of water including various dilution waters), 2.0 parts by weight of disodium hydrogen phosphate, and 125 parts by weight of the above-mentioned Lx- were added. The temperature was raised to 65°C and nitrogen purging was performed. After 30 minutes, a mixture of 72 parts by weight of pure water, 1.1 parts by weight of polyoxyethylene alkyl ether, 1.1 parts by weight of lauryltrimethylammonium chloride, and 72 parts by weight of methyltrimethoxysilane (MTMS), which had been homogenized in a homogenizer, was added dropwise to the reaction vessel over 10 minutes, and the polymerization reaction was carried out for 2 hours. Subsequently, a mixture of 3.0 parts by weight of pure water, 0.046 parts by weight of polyoxyethylene alkyl ether, 0.046 parts by weight of lauryltrimethylammonium chloride, and 3.0 parts by weight of 3-aminopropyltrimethoxysilane (3-APTMS), which had been homogenized beforehand, was added dropwise to the reaction vessel over 10 minutes, and the polymerization reaction was carried out for 2 hours to obtain latex-like core-shell particles. The conversion rate calculated from the solid content of the obtained latex was 77%. The volume-average particle size of these core-shell particles was 128 nm.

[0181] 100 parts by weight of latex core-shell particles were placed in a separable flask equipped with a stirrer, reflux condenser, and thermometer. 150 parts by weight of methyl ethyl ketone were added, and the mixture was stirred at room temperature for 30 minutes, then allowed to stand at room temperature for 1 hour. Subsequently, the mixture was stirred at 60°C for 30 minutes, then allowed to stand at 60°C for 1 hour, and then cooled to room temperature and allowed to stand overnight. The solidified particle layer and the clear solvent layer were then separated and filtered using filter paper. The recovered solidified particles were dispersed in a mixed solvent of 140 parts by weight of methanol and 60 parts by weight of hexane, and stirred at 45°C for 30 minutes. Then, the mixture was allowed to stand at 45°C for 1 hour, and then cooled to room temperature and allowed to stand. The solidified particle layer and the clear solvent layer were separated and filtered using filter paper. The recovered solidified particles were again dispersed in the same amount of methanol / hexane mixed solvent, and the same washing procedure was performed. Subsequently, the solidified particle layer and the transparent solvent layer were separated by natural filtration using filter paper. The recovered solidified particles were further dispersed in a mixed solvent of 160 parts by weight of methyl ethyl ketone and 40 parts by weight of hexane, and stirred at 45°C for 30 minutes. Then, it was allowed to stand at 45°C for 1 hour, and then cooled to room temperature and allowed to stand. The solidified particle layer and the transparent solvent layer were separated by natural filtration using filter paper. The recovered solidified particles were dried to obtain hollow particles (P-1).

[0182] The final hollow particle (P-1) had a composition containing (i) 3 mol% of unit (a) and 97 mol% of unit (b), (ii) an average particle diameter of 124 nm, and (iii) a volume ratio of internal space to total volume of 15%.

[0183] (Comparative Example A1) In a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 300 parts by weight of pure water (total amount of water including various dilution waters), 0.40 parts by weight of tripotassium phosphate, 0.20 parts by weight of sodium β-naphthalene sulfonic acid formalin condensate, and 12 parts by weight of sodium dodecylbenzenesulfonate were added. The mixture was then heated to 50°C while stirring under a nitrogen stream. After 30 minutes, 0.019 parts by weight of ethylenediamine tetraacetyl acid disodium salt / ferrous sulfate heptahydrate chelate complex and 0.18 parts by weight of sodium formaldehyde sulfoxylate were added. A mixture of 100 parts by weight of butyl acrylate, 30 parts by weight of t-dodecyl mercaptan, and 0.16 parts by weight of cumene hydroperoxide was then added dropwise at a constant rate over 180 minutes. Ten minutes after the dropwise addition was complete, 0.040 parts by weight of cumene hydroperoxide was added, and the mixture was polymerized for 90 minutes to obtain an organic polymer latex (Lx-2) to serve as a seed.

[0184] Next, in a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 400 parts by weight of pure water (total amount of water including various dilution waters), 0.32 parts by weight of tripotassium phosphate, 0.16 parts by weight of β-naphthalene sulfonic acid formalin condensate sodium salt, and 20 parts by weight of the Lx-2 obtained above were added, and the mixture was heated to 50°C while stirring under a nitrogen stream. After 30 minutes, 0.016 parts by weight of ethylenediamine tetraacetyl acid disodium salt / ferrous sulfate heptahydrate chelate complex and 0.16 parts by weight of sodium formaldehyde sulfoxylate were added, and then a mixture of 80 parts by weight of butyl acrylate, 24 parts by weight of t-dodecyl mercaptan, and 0.13 parts by weight of cumene hydroperoxide was added dropwise at a constant rate over 160 minutes. Ten minutes after the dropwise addition was complete, 0.040 parts by weight of cumene hydroperoxide was added, and post-polymerization was carried out for 90 minutes to obtain an organic polymer latex (Lx-3) that would serve as the base particle. The conversion rate calculated from the solid content of the obtained Lx-3 was 95%.

[0185] In a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 500 parts by weight of pure water (total amount of water including various dilution waters), 3.0 parts by weight of dodecylbenzenesulfonic acid, and 25 parts by weight of the Lx-3 obtained above were added. The temperature was raised to 80°C and nitrogen purging was performed. After 30 minutes, a mixture of 75 parts by weight of pure water, 0.38 parts by weight of sodium dodecylbenzenesulfonate, 71 parts by weight of methyltrimethoxysilane (MTMS), and 4 parts by weight of 3-methacryloxypropyltrimethoxysilane (3-MPTMS), which had been homogenized in a homogenizer, was added dropwise to the reaction vessel over 10 minutes, and the polymerization reaction was carried out for 4 hours to obtain latex-like core-shell particles. The conversion rate calculated from the solid content of the obtained latex was 96%. The volume-average particle size of these core-shell particles was 69 nm.

[0186] 100 parts by weight of latex core-shell particles were placed in a separable flask equipped with a stirrer, reflux condenser, and thermometer. 200 parts by weight of acetone were added, and the mixture was stirred at room temperature for 30 minutes, then allowed to stand at room temperature for 1 hour. Subsequently, the mixture was stirred at 50°C for 30 minutes, and then allowed to stand at 50°C for 1 hour. The solidified particle layer and the clear solvent layer were separated and filtered by natural filtration using filter paper. The recovered solidified particles were dispersed in a mixed solvent of 210 parts by weight of methanol and 90 parts by weight of hexane, and stirred at 50°C for 30 minutes. Then, the mixture was allowed to stand at 50°C for 1 hour. The solidified particle layer and the clear solvent layer were separated and filtered by natural filtration using filter paper. The recovered solidified particles were dispersed in 93 parts by weight of 2-propanol to obtain a solution of hollow particles (P-2).

[0187] The final hollow particle obtained (P-2) had (i) (a) units of 0 mol% and (b) units of 97 mol% (the remaining 3 mol% was RSiO 3 / 2 The composition contained the unit (wherein R is a 3-methacryloxypropyl group), (ii) the average particle size was 54 nm, and (iii) the volume ratio of the internal space to the total volume was 27%.

[0188] (Example A2) 0.796 g of hollow particles (P-1) from Example A1, 5.904 g of bisphenol A type epoxy resin (JER828US), and 0.178 g of 2-ethyl-4-methylimidazole as an epoxy resin curing agent were mixed in a rotary-orbit mixer to obtain an epoxy resin composition (the amount of hollow particles added to the mixture consisting of epoxy resin and hollow particles was 13 vol%). This composition was poured into a silicone tube and heated and cured in an oven at 60°C for 2 hours, 180°C for 2.5 hours, and 200°C for 1 hour. The dielectric constant and dielectric loss tangent of the cured product were evaluated and the results are shown in Table 1. In addition, the presence or absence of penetration of the epoxy resin into the hollow particles and the dispersibility of the hollow particles were evaluated from TEM observation of a separately prepared cured product and the results are shown in Table 1, and the TEM image (observation magnification 40,000x) is shown in Figure 1.

[0189] (Comparative example A2) 245.43 g of a solution of the hollow particles (P-2) from Comparative Example A1 (13.65 g as hollow particles), 99.83 g of bisphenol A type epoxy resin (JER828US), and 7.30 g of methyl ethyl ketone were placed in a round-bottom flask, mixed, and devastation under reduced pressure while heating to 80°C to obtain an epoxy resin in which hollow particles were dispersed. 2.02 g of epoxy resin was added to 2.59 g of this hollow particle-dispersed epoxy resin, and then 0.129 g of 2-ethyl-4-methylimidazole as an epoxy resin curing agent and 1.01 g of N,N-dimethylformamide as a solvent were mixed to obtain an epoxy resin solution composition (the amount of hollow particles added to the mixture of epoxy resin and hollow particles was 8 vol%). This solution composition was cast onto an aluminum substrate to form a thin film. The thin film, along with the aluminum substrate, was dried in an oven at 60°C, and then heated and cured at 180°C for 2 hours. The aluminum substrate was then etched off to obtain a thin film of cured epoxy resin. Table 1 shows the results of evaluating the dielectric constant and dielectric loss tangent of this cured product. In addition, Table 1 shows the results of evaluating the presence or absence of penetration into the hollow particles of the epoxy resin and the dispersion of the hollow particles from TEM observation of a separately prepared cured product, and Figure 2 shows the TEM image (observation magnification 40,000x).

[0190] (Comparative example A3) 7.009 g of bisphenol A type epoxy resin (JER828US) ​​and 0.212 g of 2-ethyl-4-methylimidazole as an epoxy resin curing agent were mixed in a rotary-orbit mixer to obtain an epoxy resin composition. This composition was poured into a silicone tube and heated and cured in an oven at 60°C for 2 hours, 180°C for 2.5 hours, and 200°C for 1 hour. The dielectric constant and dielectric loss tangent of the cured product were evaluated and the results are shown in Table 1.

[0191] (Comparative example A4) A separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, and thermometer was filled with a mixture of 300 parts by weight of pure water, 0.9 parts by weight of sodium dodecylbenzenesulfonate, 100 parts by weight of octamethylcyclotetrasiloxane, 8 parts by weight of tetraethoxysilane, and 4 parts by weight of 3-aminopropyldimethoxymethylsilane, which had been homogenized in a homogenizer. A mixture of 4 parts by weight of dodecylbenzenesulfonic acid and 36 parts by weight of pure water was then added, and the polymerization reaction was carried out at 80°C for 5 hours. The conversion rate, calculated from the solid content of the latex (Lx-4) of the resulting silicone solid particles, was 13%.

[0192] [Table 1] Table 1 shows that when the hollow particles of this embodiment were used, the epoxy resin did not penetrate into the hollow particles, resulting in a cured product with low dielectric constant and dielectric loss tangent. Furthermore, while Comparative Example A2 had large aggregates of hollow particles in the cured product and poor dispersibility, Example A2 did not show large aggregates of hollow particles and exhibited good dispersibility. It is presumed that the amino groups of the hollow particles contributed to the improvement of particle dispersibility. From Example A2 and Comparative Example A3, it can be seen that when the hollow particles of this embodiment were used, the dielectric constant was lower than that of the epoxy resin cured product alone without particles. Moreover, from Comparative Example A2 and Comparative Example A3, it can be seen that when hollow particles without amino groups were used, the epoxy resin penetrated into the hollow particles, so the low dielectric effect due to air could not be expected. Furthermore, it is estimated that the dielectric constant of the silicone compound in the particles (approximately 3.2) was higher than that of the epoxy resin alone. Therefore, in Comparative Example A2, the dielectric constant and dielectric loss tangent increased (did not become low dielectric) compared to the epoxy resin cured product alone without particles. Furthermore, from Example A1 and Comparative Example A4, it can be seen that in Comparative Example A4, which did not use the cationic surfactant essential in this embodiment, the conversion rate in the preparation of the silicone compound having an amino group was low at 13%, indicating that polymerization did not proceed sufficiently, and therefore the product with the intended composition was not obtained. On the other hand, in Example A1, which used a cationic surfactant, the conversion rate in the preparation of the silicone compound having an amino group was high at 77%, indicating that polymerization proceeded well, and it can be said that a product with the intended composition was substantially obtained.

[0193] [Example B] The present invention will be described in detail based on Example B, but the present invention is not limited to these Examples B. The measurements and tests in Example B and Comparative Example B were carried out as follows.

[0194] [Volume-average particle diameter] The volume-average particle size was measured in the same manner as in Example A.

[0195] [Confirmation of hollow particles] The hollow structure of the particles was confirmed using a transmission electron microscope (TEM). A particle solution, in which particles were dispersed in isopropyl alcohol, was dropped onto a TEM grid. After the isopropyl alcohol dried, the particles were observed. The contrast of the particles confirmed that they were hollow.

[0196] The average particle diameter of hollow particles and the volume ratio of the internal space to the total volume of the hollow particles were determined using a transmission electron microscope (TEM). Hollow particles were dispersed in TEM embedding resin, photocured, and then ultrathin sections were cut using an ultramicrotome to prepare the observation samples. The average particle diameter was defined as the average of the outer diameters of 15-20 particles shown in the observation photographs. The outer diameter and inner diameter (hollow diameter) were also measured, and the average volume ratio was calculated according to the following formula: Volume ratio (%) = (Inner diameter / Outer diameter) 3 ×100.

[0197] [Quantification of residual silanol groups] For hollow powder particles, the residual silanol groups were quantified using 29Si-solid-state NMR and 13C-solid-state NMR measurements with a VNMRS 600 (Agilent Technologies, formerly VARIAN). Details of the experimental conditions are shown below.

[0198] <29Si NMR> ·Resonance frequency: 119.19MHz, • Measurement mode: DP / MAS method (Direct Polarization method) ·Measurement nucleus: 29Si, • Sample rotation speed: 8kHz, ·Measurement temperature: room temperature • Total number of times: 1024.

[0199] <13C NMR> ·Resonance frequency: 150.85 MHz, • Measurement mode: DP / MAS method (Direct Polarization method) ·Measurement nucleus: 13C, • Sample rotation speed: 6kHz, ·Measurement temperature: room temperature, • Total number of times: 768.

[0200] Furthermore, the remaining silanol was quantified according to the following procedures (1) to (3): (1) From 29Si solid-state NMR, the T1 and T2 structures were quantified (total value of Si-OH groups and Si-O-CH3 groups). (2) The Si-O-CH3 group was quantified by 13C solid-state NMR. (3) Subtract the value of (2) from the value of (1) to quantify the Si-OH group.

[0201] [Quantitative determination of Si-OSi(R2)3] The concentration of Si-OSi(R2)3 was calculated by subtracting the remaining Si-OH groups in the sealed hollow particles from the remaining Si-OH groups in the hollow particles (unsealed particles) obtained in step 2.

[0202] [Evaluation of dielectric properties of particle composite films] A cavity resonator perturbation method complex dielectric constant evaluation device (Kanto Electronics Applied Development) was used as the measurement device, and the dielectric constant (Dk) and dielectric loss tangent (Df) of the particle composite film were measured according to the following conditions. ·Measurement frequency: 10GHz, ·Measurement environment: temperature 22℃~24℃, humidity 45%~55%, • Sample used for measurement: The obtained particle composite film was left for 24 hours under the measurement environment described above.

[0203] (Example B1) In a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer, 60 parts by weight of pure water (total amount of water including various dilution waters), 2.150 parts by weight of polyoxyethylene alkyl ether, and 2.15 parts by weight of lauryltrimethylammonium chloride were added, and the mixture was heated to 50°C under a nitrogen stream and stirred for 30 minutes. Next, 0.001 parts by weight of ethylenediaminetetraacetate disodium / ferrous sulfate heptahydrate and 0.375 parts by weight of sodium formaldehyde sulfoxylate were added to the same five-neck separable flask, followed by 5 parts by weight of butyl acrylate and t-dodecyl mercaptan. A mixture of 1 part by weight of [the substance] and 0.008 parts by weight of paracumene hydroperoxide was added. Then, 0.002 parts by weight of paracumene hydroperoxide was added to the five-neck separable flask and stirred for 1 hour, and then 240 parts by weight of warm pure water and 0.019 parts by weight of ethylenediaminetetraacetate disodium / ferrous sulfate heptahydrate were added. Then, a mixture of 95 parts by weight of butyl acrylate, 19 parts by weight of t-dodecyl mercaptan, and 0.152 parts by weight of paracumene hydroperoxide was continuously added to the five-neck separable flask over 3 hours and 10 minutes. During the continuous addition, 0.600 parts by weight of polyoxyethylene alkyl ether and 0.600 parts by weight of lauryltrimethylammonium chloride were added to the five-neck separable flask in four portions. Finally, 0.048 parts by weight of paracumene hydroperoxide was added to the five-neck separable flask, and polymerization was carried out after 1 hour to obtain a seed organic polymer latex (Lx-1). The volume-average particle size of this organic polymer latex was 83 nm.

[0204] Next, 60 parts by weight of pure water (total amount of water including various dilution waters) and 69.4 parts by weight of the aforementioned organic polymer latex (Lx-1) were added to a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer. The mixture was then heated to 50°C under a nitrogen stream and stirred for 30 minutes. Next, 0.006 parts by weight of ethylenediaminetetraacetate disodium / ferrous sulfate heptahydrate and 0.121 parts by weight of sodium formaldehyde sulfoxylate were added to the five-neck separable flask. A mixture of 30.600 parts by weight of butyl acrylate, 6.100 parts by weight of t-dodecyl mercaptan, and 0.050 parts by weight of paracumene hydroperoxide was then continuously added over 1 hour. During the continuous addition process, 0.600 parts by weight of polyoxyethylene alkyl ether and 0.600 parts by weight of lauryltrimethylammonium chloride were added to the five-neck separable flask in three separate additions. Finally, 0.015 parts by weight of paracumene hydroperoxide was added to the five-neck separable flask, and post-polymerization was carried out for 1 hour and 30 minutes to obtain organic polymer latex (Lx-2). The volume-average particle size of this organic polymer latex was 95 nm.

[0205] Next, 500 parts by weight of pure water (total amount of water including various dilution waters), 2 parts by weight of disodium hydrogen phosphate, and 57,600 parts by weight of the aforementioned organic polymer latex (Lx-2) were added to a five-neck separable flask equipped with a stirrer, reflux condenser, nitrogen inlet, monomer addition port, and thermometer. The five-neck separable flask was heated to 65-75°C and purged with nitrogen. Separately, a mixture of 73.8 parts by weight of pure water, 1,110 parts by weight of lauryltrimethylammonium chloride, 1,110 parts by weight of polyoxyethylene alkyl ether, and 73,800 parts by weight of methyltrimethoxysilane (MTMS) was added to the five-neck separable flask at a constant rate over 10 minutes. After the addition was complete, stirring was continued for 2 hours. Then, a mixed solution of 9,800 parts by weight of pure water, 0.150 parts by weight of lauryltrimethylammonium chloride, 0.150 parts by weight of polyoxyethylene alkyl ether, and 9,800 parts by weight of 3-aminopropyltrimethoxysilane (3-APTMS) was added to the five-necked separable flask at a constant rate over 10 minutes. Stirring was then continued for another 2 hours to obtain latex-like core-shell particles (Lx-3). The volume-average particle size of these core-shell particles was 125 nm.

[0206] To 100 parts by weight of latex-like core-shell particles (Lx-3), 100 parts by weight of methyl ethyl ketone was added and the mixture was stirred at 45°C for 30 minutes to obtain solidified particles. When the solution containing these solidified particles was allowed to stand, it separated into a solidified particle layer and a clear supernatant layer. The solidified particles were then filtered off by natural filtration using filter paper. 200 parts by weight of a mixed solvent of 76% by weight of acetone and 24% by weight of n-hexane was added to the solidified particles and the mixture was stirred at 45°C for 30 minutes. When the solution containing these solidified particles was allowed to stand, it separated into a solidified particle layer and a clear supernatant layer. The solidified particle layer was then filtered off by natural filtration using filter paper. The solidification and filtration with the same mixed solvent of 76% by weight of acetone and 24% by weight of n-hexane was repeated to recover the solidified particle layer. The mixture was then dried in an oven at 120°C for 5 hours to obtain hollow particles (P-1). The removal of organic polymers from the core-shell particles was confirmed by TEM. At this time, the volume ratio of the internal space to the total volume of the hollow particle (P-1) was 27%.

[0207] Next, 100 parts by weight of hollow particles (P-1) were dissolved in 2366 parts by weight of pyridine, and 592 parts by weight of trimethylsilylimidazole (TMSI), a silanol encapsulant, was added (TMSI:pyridine = 1:4). After reacting the hollow particles (P-1) with the silanol encapsulant at 75°C for 15 hours, hollow particles (P-2) with the remaining silanol groups encapsulated were obtained. The remaining silanol concentration was 0.26 mmol / g per 1 g of hollow particles (P-2). This corresponds to encapsulating 42% of the silanol groups remaining in the unencapsulated particles (Comparative Example B1, P-1). In other words, in hollow particles (P-2), of the 100 mol% of constituent units (1) to (4) contained in the layer made of a silicone compound, the total of constituent units (1) and (2) is 6 mol%, and the total of constituent units (3) and (4) is 94 mol%. These hollow particles (P-2) were dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a dispersion (D-1).

[0208] 100 mol of 2,2'-dimethylbiphenyl-4,4'-diamine (m-TB), 40 mol of pyromellitic dianhydride (PMDA), 40 mol of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), and 20 mol of 4,4'-oxydiphthalic anhydride (ODPA) were polymerized in N,N-dimethylformamide (DMF). During polymerization, a dispersion (D-1) was mixed to obtain a mixture (M-1) of 90% by weight of polyamic acid and 10% by weight of hollow particles (P-2).

[0209] To 100 parts by weight of this mixture (M-1), 50 parts by weight of a curing agent consisting of acetic anhydride / isoquinoline / DMF (20 parts by weight / 6 parts by weight / 24 parts by weight) was added, and the mixture was stirred and degassed at a temperature below 0°C. The resulting solution was cast onto aluminum foil and heated in an oven at 120°C for 180 seconds, after which a self-supporting gel film was peeled off the aluminum foil. The gel film was fixed to a metal frame and dried and imidized by heat treatment at 250°C for 60 seconds, followed by 300°C for 200 seconds, to obtain a particle composite film (PI-1) of hollow particles (P-2) and polyimide with a film thickness of 20 μm. At this time, the volume ratio of the internal space to the total volume of the hollow particles (P-2) was 43%. When the dielectric properties of this particle composite film (PI-1) were evaluated, the dielectric constant (Dk) was 2.62 (Table 2). This value was lower than the dielectric constant (Dk) of polyimide films (Comparative Example B2, PI-4) and particle composite films of silanol-unsealed hollow particles and polyimide (Comparative Example B1, PI-3). The dielectric loss tangent (Df) value was also lower than that of particle composite films of silanol-unsealed hollow particles and polyimide (Comparative Example B1, PI-3). Although the dielectric loss tangent (Df) value was higher than that of polyimide films (Comparative Example B2, PI-4), it can be said to be sufficiently low from the perspective of use in the telecommunications industry, such as 5G (high-speed network) applications.

[0210] (Example B2) 100 parts by weight of the hollow particle (P-1) from Example B1 was dissolved in 1000 parts by weight of toluene, and 681 parts by weight of hexamethylenedisilazane (HMDS), a silanol encapsulant, and 68 parts by weight of trifluoroacetic acid, a catalyst, were added. After reacting the hollow particle (P-1) with the silanol encapsulant at 60°C for 10 hours, hollow particle (P-3) with the remaining silanol groups encapsulated was obtained. The remaining silanol concentration was 0.17 mmol / g per 1 g of hollow particle (P-3). This corresponds to encapsulating 62% of the silanol groups remaining in the unencapsulated particles (Comparative Example B1, P-1). In other words, in the hollow particle (P-3), of the 100 mol% of constituent units (1) to (4) contained in the layer made of a silicone compound, the total of constituent units (1) and (2) is 6 mol%, and the total of constituent units (3) and (4) is 94 mol%. These hollow particles (P-3) were dispersed in NMP to obtain a dispersion (D-2).

[0211] 100 mol of m-TB, 40 mol of PMDA, 40 mol of BPDA, and 20 mol of ODPA were polymerized in DMF. During polymerization, a dispersion (D-2) was mixed in to obtain a mixture (M-2) of 90% by weight of polyamic acid and 10% by weight of hollow particles (P-3).

[0212] To 100 parts by weight of this mixture (M-2), 50 parts by weight of a curing agent consisting of acetic anhydride / isoquinoline / DMF (20 parts by weight / 6 parts by weight / 24 parts by weight) was added, and the mixture was stirred and degassed at a temperature below 0°C. The resulting solution was cast onto aluminum foil and heated in an oven at 120°C for 180 seconds, after which a self-supporting gel film was peeled off the aluminum foil. The gel film was fixed to a metal frame and dried and imidized by heat treatment at 250°C for 60 seconds, followed by 300°C for 200 seconds, to obtain a particle composite film (PI-2) of hollow particles (P-3) and polyimide with a film thickness of 20 μm. At this time, the volume ratio of the internal space to the total volume of the hollow particles (P-3) was 44%. When the dielectric properties of this particle composite film (PI-2) were evaluated, the dielectric constant (Dk) was 2.01 and the dielectric loss tangent (Df) was 0.0026 (Table 2). The dielectric constant (Dk) value was lower than that of the polyimide film (Comparative Example B2, PI-4) and the particle composite film of silanol-unsealed hollow particles and polyimide (Comparative Example B1, PI-3). The dielectric loss tangent (Df) value was also lower than that of the polyimide film (Comparative Example B2, PI-4) and the particle composite film of silanol-unsealed hollow particles and polyimide (Comparative Example B1, PI-3).

[0213] (Comparative Example B1) Hollow particles (P-1) were obtained in the same manner as in Example B1. The residual silanol concentration of the hollow particles (P-1) was quantified to be 0.45 mmol / g per 1 g of hollow particles (P-1). In other words, of the 100 mol% of constituent units (1) to (4) contained in the layer made of the silicone compound, the total of constituent units (1) and (2) was 7 mol%, and the total of constituent units (3) and (4) was 93 mol%. These hollow particles (P-1) were dispersed in NMP to obtain dispersion (D-3).

[0214] 100 mol of m-TB, 40 mol of PMDA, 40 mol of BPDA, and 20 mol of ODPA were polymerized in DMF. During polymerization, a dispersion (D-3) was mixed in to obtain a mixture (M-3) of 90% by weight of polyamic acid and 10% by weight of hollow particles (P-1).

[0215] To 100 parts by weight of this mixture (M-3), 50 parts by weight of a curing agent consisting of acetic anhydride / isoquinoline / DMF (20 parts by weight / 6 parts by weight / 24 parts by weight) was added, and the mixture was stirred and degassed at a temperature below 0°C. The resulting solution was cast onto aluminum foil and heated in an oven at 120°C for 180 seconds, after which a self-supporting gel film was peeled off the aluminum foil. The gel film was fixed to a metal frame and dried and imidized by heat treatment at 250°C for 60 seconds, followed by 300°C for 200 seconds, to obtain a particle composite film (PI-3) of silanol-unsealed hollow particles (P-1) and polyimide with a film thickness of 20 μm. At this time, the volume ratio of the internal space to the total volume of the hollow particles (P-1) was 36%. When the dielectric properties of this particle composite film (PI-3) were evaluated, the dielectric constant (Dk) was 2.96 and the dielectric loss tangent (Df) was 0.0046 (Table 2). The dielectric constant (Dk) value was lower than that of the polyimide film (Comparative Example B2, PI-4).

[0216] (Comparative example B2) 100 mol of m-TB, 40 mol of PMDA, 40 mol of BPDA, and 20 mol of ODPA were polymerized in DMF to obtain a polyamic acid solution.

[0217] To 100 parts by weight of this polyamic acid solution, 50 parts by weight of a curing agent consisting of acetic anhydride / isoquinoline / DMF (20 parts by weight / 6 parts by weight / 24 parts by weight) was added, and the mixture was stirred and degassed at a temperature below 0°C. The resulting solution was cast onto aluminum foil and heated in an oven at 120°C for 180 seconds, after which a self-supporting gel film was peeled off the aluminum foil. The gel film was fixed to a metal frame and dried and imidized by heat treatment at 250°C for 60 seconds, followed by 300°C for 200 seconds, to obtain a polyimide film (PI-4) with a thickness of 20 μm. When the dielectric properties of this polyimide film (PI-4) were evaluated, the dielectric constant (Dk) was 3.26 and the dielectric loss tangent (Df) was 0.0028 (Table 2). [Table 2] [Industrial applicability]

[0218] According to embodiments of the present invention, hollow particles exhibiting excellent low dielectric constant can be provided. Therefore, embodiments of the present invention can be suitably used to obtain circuit boards having excellent propagation speed and low transmission loss. For this reason, embodiments of the present invention can be suitably used in fields such as electronic equipment including communication devices.

Claims

1. (a) R １ SiO ３／２ Unit (in the formula, R) １ ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies hereinafter. ), R １ Si(OH)O ２／２ Units, and R １ Si(OH) ２ O １／２ One or more units selected from a group of units, totaling 0.1 to 15 mol%, (b) R ２ SiO ３／２ unit (wherein R ２ represents an alkyl group having 1 to 4 carbon atoms and no amino group. The same applies hereinafter.), R ２ Si(OH)O ２／２ unit, and R ２ Si(OH) ２ O １／２ One or more units selected from the group consisting of units, in total 85 to 99.9 mol%, and Hollow particles having a layer made of a silicone-based compound containing [a specific compound].

2. A hollow particle having a layer made of a silicone compound containing the following constituent units (1) to (4), The sum of (1) and (2) is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSI(R ２ ) ３ Hollow particles with a quantity of 0.01 mmol / g or more: (1) R １ SiO ３／２ Unit (in the formula, R) １ (This represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies hereafter.) R １ Si(OH)O ２／２ Units and R １ Si(OH) ２ O １／２ unit One or more units selected from the group consisting of the following; (2) R １ Si(OSi(R ２ ) ３ ) O ２／２ Unit (in the formula, R) ２ These represent alkyl groups having 1 to 4 carbon atoms, which may be the same or different. (The same applies hereinafter.) and R １ Si(OSi(R ２ ) ３ ) ２ O １／２ unit One or more units selected from the group consisting of the following; (3) Caution ３ SiO ３／２ Unit (in the formula, R) ３ This represents an alkyl group with 1 to 4 carbon atoms that does not contain an amino group. The same applies hereafter.) R ３ Si(OH)O ２／２ Units and R ３ Si(OH) ２ O １／２ unit One or more units selected from the group consisting of the following; (4) R ３ Si(OSi(R ２ ) ３ ) O ２／２ Units and R ３ Si(OSi(R ２ ) ３ ) ２ O １／２ unit One or more units selected from the group consisting of the following.

3. The hollow particle according to claim 2, wherein the residual Si-OH content is 0.35 mmol / g or less.

4. A hollow particle according to any one of claims 1 to 3, wherein the particle diameter is 10 to 1000 nm.

5. A hollow particle according to any one of claims 1 to 4, wherein the volume ratio of the internal space to the total volume is 10 to 70%.

6. A dispersion liquid obtained by dispersing the hollow particles described in any one of claims 1 to 5 in a solvent.

7. A resin composition comprising hollow particles according to any one of claims 1 to 6 and a matrix resin.

8. The resin composition according to claim 7, wherein the matrix resin is an epoxy resin or a polyimide resin.

9. A low dielectric material obtained from the resin composition according to claim 7 or 8.

10. A method for producing a dispersion of hollow particles, comprising the following steps: Step 1. A step of polymerizing acrylic monomers in an aqueous medium in the presence of a surfactant containing a cationic surfactant to produce particles containing an acrylic polymer; Step 2. On the surface of the particles containing the acrylic polymer obtained in Step 1, (a) R １ SiO ３／２ Unit (in the formula, R) １ ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies hereinafter. ), R １ Si(OH)O ２／２ Units, and R １ Si(OH) ２ O １／２ (b) R ２ SiO ３／２ Unit (in the formula, R) ２ ) represents an alkyl group having 1 to 4 carbon atoms that does not contain an amino group. The same applies hereinafter. ), R ２ Si(OH)O ２／２ Units, and R ２ Si(OH) ２ O １／２ A step of producing multilayer particles by arranging a condensate of silanes, which are raw materials for one or more units selected from a group of units, wherein the condensate contains a total of 0.1 to 20 mol% of one or more units described in (a) and a total of 80 to 99.9 mol% of one or more units described in (b); Step 3. A step to obtain a dispersion of hollow particles containing an organic solvent in the core, by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 2 using an organic solvent.

11. A method for producing hollow particles, comprising the step of drying the dispersion of hollow particles obtained by the method for producing a dispersion of hollow particles according to claim 10 to remove the organic solvent inside the hollow particles and obtain hollow particles.

12. A method for producing hollow particles, comprising the following steps: Step 1. In the presence of a cationic surfactant, (1) R is applied to the surface of the particles containing the acrylic polymer. １ SiO ３／２ Unit (in the formula, R) １ ) represents an alkyl group having 1 to 4 carbon atoms and containing an amino group. The same applies hereinafter. ), R １ Si(OH)O ２／２ Units, and R １ Si(OH) ２ O １／２ Silanes that serve as raw materials for one or more units selected from a group of units, and (3) R ３ SiO ３／２ Unit (in the formula, R) ３ ) represents an alkyl group having 1 to 4 carbon atoms that does not contain an amino group. The same applies hereinafter. ), R ３ Si(OH)O ２／２ Units, and R ３ Si(OH) ２ O １／２ A process for producing multilayer particles by arranging silanes, which are raw materials for one or more units selected from a group of units, and condensates thereof; Step 2. A step to obtain hollow particles by extracting and removing the acrylic polymer from inside the multilayer particles obtained in Step 1 using an organic solvent; Step 3. R that constitutes the hollow particles obtained in Step 2 １ Si(OH)O ２／２ unit, R １ Si(OH) ２ O １／２ unit, R ３ Si(OH)O ２／２ unit, and R ３ Si(OH) ２ O １／２ unit, reacting a sealing agent with one or more units selected from the group consisting of, (2) R １ Si(OSi(R ２ )) ３ O ２／２ unit (wherein R ２ each represents the same or different alkyl group having 1 to 4 carbon atoms. The same applies hereinafter.) and R １ Si(OSi(R ２ )) ３ ) ２ O １／２ unit, (4) R ３ Si(OSi(R ２ )) ３ O ２／２ unit and R ３ Si(OSi(R ２ )) ３ ) ２ O １／２ a step of sealing a hydroxyl group for generating one or more units selected from the group consisting of units The sum of (1) and (2) above is 0.1 to 20 mol%, and the sum of (3) and (4) is 80 to 99.9 mol%, and Si-OSi(R ２ ) ３ A process in which the quantity is 0.01 mmol / g or more.

13. The method for producing hollow particles according to claim 12, wherein step 2 is a step of extracting and removing the acrylic polymer inside the multilayer particles obtained in step 1 using an organic solvent, and then drying them to obtain hollow particles.

14. (a) A total of 0.1 to 20 mol% of one or more units selected from the group consisting of R1SiO3 / 2 units (wherein R1 represents an alkyl group having an amino group and having 1 to 4 carbon atoms; the same applies hereinafter), R1Si(OH)O2 / 2 units, and R1Si(OH)2O1 / 2 units, (b) A total of 80 to 99.9 mol% of one or more units selected from the group consisting of R₂SiO₃ / 2 units (wherein R₂ represents an alkyl group having 1 to 4 carbon atoms that does not have an amino group; the same applies hereinafter), R₂Si(OH)O₂ / 2 units, and R₂Si(OH)₂O₁ / 2 units, A low dielectric material obtained from a resin composition containing hollow particles having a layer made of a silicone compound containing a matrix resin.

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